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Sample records for ni-based organometallic compounds

  1. Organometallic chemistry of bimetallic compounds

    SciTech Connect

    Casey, C.P.

    1991-07-01

    This report consists of six sections: heterobimetallic dihydrides, early-late transition metal heterobimetallic compounds, amphiphilic carbene complexes and hydroxycarbene complexes, diiron compounds with bridging hydrocarbon ligands, diphosphine chelates with natural bite angles near 120 degrees, and synthesis and reactions of M=M compounds. (WET)

  2. Nonsteroidal Anti-inflammatory-Organometallic Anticancer Compounds.

    PubMed

    Păunescu, Emilia; McArthur, Sarah; Soudani, Mylène; Scopelliti, Rosario; Dyson, Paul J

    2016-02-15

    Compounds that combine metal-based drugs with covalently linked targeted organic agents have been shown, in some instances, to exhibit superior anticancer properties compared to the individual counterparts. Within this framework, we prepared a series of organometallic ruthenium(II)- and osmium(II)-p-cymene complexes modified with the nonsteroidal anti-inflammatory drugs (NSAIDs) indomethacin and diclofenac. The NSAIDs are attached to the organometallic moieties via monodentate (pyridine/phosphine) or bidentate (bipyridine) ligands, affording piano-stool Ru(II) and Os(II) arene complexes of general formula [M(η(6)-p-cymene)Cl2(N)], where N is a pyridine-based ligand, {2-(2-(1-(4-chlorobenzoyl)-5-methoxy-2-methyl-1H-indol-3-yl)acetoxy)ethyl-3-(pyridin-3-yl)propanoate} or {2-(2-(2-((2,6-dichlorophenyl)amino)phenyl)acetoxy)ethyl-3-(pyridin-3-yl)propanoate}, [M(η(6)-p-cymene)Cl2(P)], where P is a phosphine ligand, {2-(2-(1-(4-chlorobenzoyl)-5-methoxy-2-methyl-1H-indol-3-yl)acetoxy)ethyl-4-(diphenylphosphanyl)benzoate} or {2-(2-(2-((2,6-dichlorophenyl)amino)phenyl)acetoxy)ethyl-4-(diphenylphosphanyl)benzoate, and [M(η(6)-p-cymene)Cl(N,N')][Cl], where N,N' is a bipyridine-based ligand, (4'-methyl-[2,2'-bipyridin]-4-yl)methyl-2-(1-(4-chlorobenzoyl)-5-methoxy-2-methyl-1H-indol-3-yl)acetate), (4'-methyl-[2,2'-bipyridin]-4-yl)methyl-2-(2-((2,6-dichlorophenyl)amino)phenyl)acetate), (bis(2-(2-(1-(4-chlorobenzoyl)-5-methoxy-2-methyl-1H-indol-3-yl)acetoxy)ethyl)[2,2'-bipyridine]-5,5'-dicarboxylate), or (bis(2-(2-(2-((2,6-dichlorophenyl)amino)phenyl)acetoxy)ethyl)[2,2'-bipyridine]-5,5'-dicarboxylate). The antiproliferative properties of the complexes were assessed in human ovarian cancer cells (A2780 and A2780cisR, the latter being resistant to cisplatin) and nontumorigenic human embryonic kidney (HEK-293) cells. Some of the complexes are considerably more cytotoxic than the original drugs and also display significant cancer cell selectivity. PMID:26824462

  3. Molecular switches in carbon-rich organometallic compounds: Theoretical aspects

    NASA Astrophysics Data System (ADS)

    Costuas, Karine

    2015-01-01

    Organometallic complexes associated with an appropriate choice of ancillary ligands reveal to have a wide range of physical properties leading to promising applications when incorporated in nano-size devices. The challenge is to design innovative multifunctional compounds based on redox active carbon-rich organometallics associated with spin carriers and/or photochromic units. A multidisciplinary approach in this area has proved to be efficient in a series a systems combining carbon-rich bridging ligands and redox metallic moieties. In this domain, the role of theoretical investigations based on quantum mechanics tools have a crucial role in rationalizing and in helping designing systems possessing target properties.

  4. Molecular switches in carbon-rich organometallic compounds: Theoretical aspects

    SciTech Connect

    Costuas, Karine

    2015-01-22

    Organometallic complexes associated with an appropriate choice of ancillary ligands reveal to have a wide range of physical properties leading to promising applications when incorporated in nano-size devices. The challenge is to design innovative multifunctional compounds based on redox active carbon-rich organometallics associated with spin carriers and/or photochromic units. A multidisciplinary approach in this area has proved to be efficient in a series a systems combining carbon-rich bridging ligands and redox metallic moieties. In this domain, the role of theoretical investigations based on quantum mechanics tools have a crucial role in rationalizing and in helping designing systems possessing target properties.

  5. A Review of the Tissue Residue Approach for Organic and Organometallic Compounds in Aquatic Organisms

    EPA Science Inventory

    This paper reviews the tissue residue approach (TRA) for toxicity assessment as it applies to organic chemicals and some organometallic compounds (tin, mercury, and lead). Specific emphasis was placed on evaluating key factors that influence interpretation of critical body resid...

  6. Facile Separation of Regioisomeric Compounds by a Heteronuclear Organometallic Capsule.

    PubMed

    Zhang, Wen-Ying; Lin, Yue-Jian; Han, Ying-Feng; Jin, Guo-Xin

    2016-08-24

    Owing to the often-similar physical and chemical properties of structural isomers of organic molecules, large efforts have been made to develop efficient strategies to isolate specific isomers. However, facile separation of regioisomeric compounds remains difficult. Here we demonstrate a universal organometallic capsule in which two silver centers are rigidly separated from each other by two tetranuclear [Rh4] pyramidal frustums, which selectively encapsulate a specific isomer from mixtures. Not only is the present heterometallic capsule suitable as a host for the encapsulation of a series of aromatic compounds, but also the receptor shows widely differing specificity for the various isomers. Direct experimental evidence is provided for the selective encapsulation of a series of para (p)-disubstituted benzene derivatives, such as p-xylene, p-dichlorobenzene, p-dibromobenzene, and p-diiodobenzene. The size and shape matching, as well as the Ag-π interactions, are the main forces governing the extent of molecular recognition. The encapsulated guest p-xylene can be released by using the solid-liquid solvent washing strategy, and the other guest molecules are easily liberated by using light stimulus. PMID:27463561

  7. Group 9 organometallic compounds for therapeutic and bioanalytical applications.

    PubMed

    Ma, Dik-Lung; Chan, Daniel Shiu-Hin; Leung, Chung-Hang

    2014-12-16

    CONSPECTUS: Compared with organic small molecules, metal complexes offer several distinct advantages as therapeutic agents or biomolecular probes. Carbon atoms are typically limited to linear, trigonal planar, or tetrahedral geometries, with a maximum of two enantiomers being formed if four different substituents are attached to a single carbon. In contrast, an octahedral metal center with six different substituents can display up to 30 different stereoisomers. While platinum- and ruthenium-based anticancer agents have attracted significant attention in the realm of inorganic medicinal chemistry over the past few decades, group 9 complexes (i.e., iridium and rhodium) have garnered increased attention in therapeutic and bioanalytical applications due to their adjustable reactivity (from kinetically liable to substitutionally inert), high water solubility, stability to air and moisture, and relative ease of synthesis. In this Account, we describe our efforts in the development of group 9 organometallic compounds of general form [M(C(∧)N)2(N(∧)N)] (where M = Ir, Rh) as therapeutic agents against distinct biomolecular targets and as luminescent probes for the construction of oligonucleotide-based assays for a diverse range of analytes. Earlier studies by researchers had focused on organometallic iridium(III) and rhodium(III) half-sandwich complexes that show promising anticancer activity, although their precise mechanisms of action still remain unknown. More recently, kinetically-inert group 9 complexes have arisen as fascinating alternatives to organic small molecules for the specific targeting of enzyme activity. Research in our laboratory has shown that cyclometalated octahedral rhodium(III) complexes were active against Janus kinase 2 (JAK2) or NEDD8-activating enzyme (NAE) activity, or against NO production leading to antivasculogenic activity in cellulo. At the same time, recent interest in the development of small molecules as modulators of protein

  8. Preparation of nanoparticles and organometallic compounds via the SMAD technique

    NASA Astrophysics Data System (ADS)

    Ponce, Audaldo A.

    The SMAD method is a versatile synthetic technique for preparation of organometallic compounds, colloids and nanostructured materials from metals and semiconductors. In this work we use this technique to prepare beta-diketonate complexes of Ba and Cu, nanoparticles of Fe-SiO and copper, and for first time nanoparticles of ionic salt-like compounds. The evaporation and cocondensation of Fe, SiO, and an organic solvent, produces nanoparticles of Fe-SiO that when heat treated and passivated, acquire a core-shell structure that protects the iron core from oxidation, preserving its magnetic properties. beta-Diketonate complexes of Ba and Cu have been prepared free of water and with a considerable purity. Moreover, a striking finding was the dependence of the reactivity of the copper particles with their size toward the formation of the beta-diketonate complex. Nanocrystalline particles of copper have been prepared, and their chemical and catalytic reactivity have been tested in the Ullman reaction and the hydrogenation of CO2 to form CH3OH. Their chemical reactivity in the Ullman reaction is proportional to their surface area, and more reactive that those found in literature, with a maximum yield of 90% biphenyl at 150°C after 6 h. for the Cu*/toluene sample. Their catalytic activity tested using nanocrystalline ZnO as a support, resulted in a maximum conversion of 80% from CO2 to CH3OH. Nanocrystalline LiF particles have been successfully prepared with surface areas of 230--520 m2/g and with crystallite size of 5--10 nm. These particles present resistance to sintering when heated from room temperature up to 200°C. These samples can be densified without crystallite growth.

  9. 40 CFR 721.10414 - Polycyclic polyamine diester organometallic compound (generic) (P-10-358).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Polycyclic polyamine diester organometallic compound (generic) (P-10-358). 721.10414 Section 721.10414 Protection of Environment ENVIRONMENTAL... compound (generic) (P-10-358). (a) Chemical substance and significant new uses subject to reporting....

  10. 40 CFR 721.10414 - Polycyclic polyamine diester organometallic compound (generic) (P-10-358).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Polycyclic polyamine diester organometallic compound (generic) (P-10-358). 721.10414 Section 721.10414 Protection of Environment ENVIRONMENTAL... compound (generic) (P-10-358). (a) Chemical substance and significant new uses subject to reporting....

  11. 40 CFR 721.10414 - Polycyclic polyamine diester organometallic compound (generic) (P-10-358).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Polycyclic polyamine diester organometallic compound (generic) (P-10-358). 721.10414 Section 721.10414 Protection of Environment ENVIRONMENTAL... compound (generic) (P-10-358). (a) Chemical substance and significant new uses subject to reporting....

  12. Model for the Vaporization of Mixed Organometallic Compounds in the Metalorganic Chemical Vapor Deposition of High Temperature Superconducting Films

    NASA Technical Reports Server (NTRS)

    Meng, Guangyao; Zhou, Gang; Schneider, Roger L.; Sarma, Bimal K.; Levy, Moises

    1993-01-01

    A model of the vaporization and mass transport of mixed organometallics from a single source for thin film metalorganic chemical vapor deposition is presented. A stoichiometric gas phase can be obtained from a mixture of the organometallics in the desired mole ratios, in spite of differences in the volatilities of the individual compounds. Proper film composition and growth rates are obtained by controlling the velocity of a carriage containing the organometallics through the heating zone of a vaporizer.

  13. Using Molecular Modeling in Teaching Group Theory Analysis of the Infrared Spectra of Organometallic Compounds

    ERIC Educational Resources Information Center

    Wang, Lihua

    2012-01-01

    A new method is introduced for teaching group theory analysis of the infrared spectra of organometallic compounds using molecular modeling. The main focus of this method is to enhance student understanding of the symmetry properties of vibrational modes and of the group theory analysis of infrared (IR) spectra by using visual aids provided by…

  14. Organometallic chemistry of bimetallic compounds. Final progress report

    SciTech Connect

    Casey, C.P.

    1991-07-01

    This report consists of six sections: heterobimetallic dihydrides, early-late transition metal heterobimetallic compounds, amphiphilic carbene complexes and hydroxycarbene complexes, diiron compounds with bridging hydrocarbon ligands, diphosphine chelates with natural bite angles near 120 degrees, and synthesis and reactions of M=M compounds. (WET)

  15. Five-membered metallacycles of titanium and zirconium--attractive compounds for organometallic chemistry and catalysis.

    PubMed

    Rosenthal, Uwe; Burlakov, Vladimir V; Bach, Marc A; Beweries, Torsten

    2007-05-01

    In these days a renaissance of metallacycles as an increasingly important class of organometallic compounds for synthetic and catalytic applications is evident, making such very attractive for a plethora of investigations. Titanocene and zirconocene bis(trimethylsilyl)acetylene complexes, regarded as three-membered metallacycles (1-metallacyclopropenes), present a rich chemistry towards unsaturated molecules. By elimination of the alkyne these complexes form by reaction with unsaturated compounds five-membered titana- and zirconacycles, all of which are relevant to stoichiometric and catalytic C-C coupling and cleavage reactions of unsaturated molecules. PMID:17471397

  16. Absorption of organic compounds and organometallics on ceramic substrates for wear reduction

    SciTech Connect

    Kennedy, P.J.; Agarwala, V.S.

    1996-12-31

    The concept of employing thermally stable compounds (that is, metal oxides) as high temperature vapor phase ceramic lubricants was investigated. A major part of this study was devoted to the development of various calorimetric and tribological techniques that could be used to determine interfacial reactions between thermally stable compounds and ceramic substrates such as zirconia and alumina. This interaction is pivotal in understanding the mechanism of high temperature lubricity. The approach consisted of selecting low sublimation temperature materials and measuring their thermodynamic interactions as vapors with the ceramic substrates. The materials studied included two easily sublimable organic compounds (that is, naphthalene and salicylic acid) and several organometallics (for example, copper phthalocyanine). Thermodynamic data such as heat of adsorption, packing density, and reversibility of the adsorption were obtained on some of these compounds and were related to wear characteristics. All of these compounds provided effective lubrication at room temperature. Copper phthalocyanine was an effective lubricant at temperatures up to 400 C.

  17. Thermal lens and all optical switching of new organometallic compound doped polyacrylamide gel

    NASA Astrophysics Data System (ADS)

    Badran, Hussain Ali

    In this work thermal lens spectrometry (TLS) is applied to investigate the thermo-optical properties of new organometallic compound containing azomethine group, Dichloro bis [2-(2-hydroxybenzylideneamino)-5-methylphenyl] telluride platinum(II), doped polyacrylamide gel using transistor-transistor logic (TTL) modulated cw 532 nm laser beam as an excitation beam modulated at 10 Hz frequency and probe beam wavelength 635 nm at 14 mW. The technique is applied to determine the thermal diffusivities, ds/dT and the linear thermal expansion coefficient of the sample. All-optical switching effects with low background and high stability are demonstrated.

  18. Anti-leishmanial activity of heteroleptic organometallic Sb(v) compounds.

    PubMed

    Ali, Muhammad Irshad; Rauf, Muhammad Khawar; Badshah, Amin; Kumar, Ish; Forsyth, Craig M; Junk, Peter C; Kedzierski, Lukasz; Andrews, Philip C

    2013-12-28

    In seeking new drugs for the treatment of the parasitic disease Leishmaniasis, an extensive range of organometallic antimony(v) dicarboxylates of the form [SbR3(O2CR')2] have been synthesised, characterised and evaluated. The organometallic moieties (R) in the complexes vary in being Ph, tolyl (o, m or p), or benzyl. The carboxylates are predominantly substituted benzoates with some compounds incorporating acetato or cinnamato ligands. The crystal structures of [Sb(p-Tol)3(O2CC6H2-3,4,5-(OMe)3)2]·0.5PhMe and [SbPh3(m-CH3C6H4CH2CO2)2] were determined and shown to adopt a typical trigonal pyramidal geometry, being monomeric with a five coordinate Sb centre. In total, the biological activity of 26 Sb(v) compounds was assessed against the Leishmania major parasite, and also human fibroblast skin cells to give a measure of general toxicity. Of these, 11 compounds (predominantly substituted benzoates with m- or p-tolyl ligands) proved to be highly effective against the parasite amastigotes at concentrations of 0.5-3.5 μM, while being non-toxic towards the mammalian cells at levels below 25 μM, making them highly promising drug candidates. PMID:24077559

  19. A review of the tissue residue approach for organic and organometallic compounds in aquatic organisms.

    PubMed

    McElroy, Anne E; Barron, Mace G; Beckvar, Nancy; Driscoll, Susan B Kane; Meador, James P; Parkerton, Tom F; Preuss, Thomas G; Steevens, Jeffery A

    2011-01-01

    This paper reviews the tissue residue approach (TRA) for toxicity assessment as it applies to organic chemicals and some organometallic compounds (Sn, Hg, and Pb) in aquatic organisms. Specific emphasis was placed on evaluating key factors that influence interpretation of critical body residue (CBR) toxicity metrics including data quality issues, lipid dynamics, choice of endpoints, processes that alter toxicokinetics and toxicodynamics, phototoxicity, species- and life stage-specific sensitivities, and biotransformation. The vast majority of data available on TRA is derived from laboratory studies of acute lethal responses to organic toxicants exhibiting baseline toxicity. Application of the TRA to various baseline toxicants as well as substances with specific modes of action via receptor-mediated processes, such as chlorinated aromatic hydrocarbons, pesticides, and organometallics is discussed, as is application of TRA concepts in field assessments of tissue residues. In contrast to media-based toxicity relationships, CBR values tend to be less variable and less influenced by factors that control bioavailability and bioaccumulation, and TRA can be used to infer mechanisms of toxic action, evaluate the toxicity of mixtures, and interpret field data on bioaccumulated toxicants. If residue-effects data are not available, body residues can be estimated, as has been done using the target lipid model for baseline toxicants, to derive critical values for risk assessment. One of the primary unresolved issues complicating TRA for organic chemicals is biotransformation. Further work on the influence of biotransformation, a better understanding of contaminant lipid interactions, and an explicit understanding of the time dependency of CBRs and receptor-mediated toxicity are all required to advance this field. Additional residue-effects data on sublethal endpoints, early life stages, and a wider range of legacy and emergent contaminants will be needed to improve the ability

  20. Systems and methods for solar energy storage, transportation, and conversion utilizing photochemically active organometallic isomeric compounds and solid-state catalysts

    DOEpatents

    Vollhardt, K. Peter C.; Segalman, Rachel A; Majumdar, Arunava; Meier, Steven

    2015-02-10

    A system for converting solar energy to chemical energy, and, subsequently, to thermal energy includes a light-harvesting station, a storage station, and a thermal energy release station. The system may include additional stations for converting the released thermal energy to other energy forms, e.g., to electrical energy and mechanical work. At the light-harvesting station, a photochemically active first organometallic compound, e.g., a fulvalenyl diruthenium complex, is exposed to light and is photochemically converted to a second, higher-energy organometallic compound, which is then transported to a storage station. At the storage station, the high-energy organometallic compound is stored for a desired time and/or is transported to a desired location for thermal energy release. At the thermal energy release station, the high-energy organometallic compound is catalytically converted back to the photochemically active organometallic compound by an exothermic process, while the released thermal energy is captured for subsequent use.

  1. Cyclopentadienyl-ruthenium(II) and iron(II) organometallic compounds with carbohydrate derivative ligands as good colorectal anticancer agents.

    PubMed

    Florindo, Pedro R; Pereira, Diane M; Borralho, Pedro M; Rodrigues, Cecília M P; Piedade, M F M; Fernandes, Ana C

    2015-05-28

    New ruthenium(II) and iron(II) organometallic compounds of general formula [(η(5)-C5H5)M(PP)Lc][PF6], bearing carbohydrate derivative ligands (Lc), were prepared and fully characterized and the crystal structures of five of those compounds were determined by X-ray diffraction studies. Cell viability of colon cancer HCT116 cell line was determined for a total of 23 organometallic compounds and SAR's data analysis within this library showed an interesting dependency of the cytotoxic activity on the carbohydrate moiety, linker, phosphane coligands, and metal center. More importantly, two compounds, 14Ru and 18Ru, matched oxaliplatin IC50 (0.45 μM), the standard metallodrug used in CC chemotherapeutics, and our leading compound 14Ru was shown to be significantly more cytotoxic than oxaliplatin to HCT116 cells, triggering higher levels of caspase-3 and -7 activity and apoptosis in a dose-dependent manner. PMID:25923600

  2. Organometallic chemistry of bimetallic compounds. Progress report, January 1992--July 1995

    SciTech Connect

    Casey, C.P.

    1994-07-01

    Four main projects at the interface between organometallic chemistry and homogeneous catalysis were pursued. All were designed to give increased understanding of the mechanisms of organometallic reactions related to homogeneous and heterogeneous catalysis. In addition, a minor study involving {eta}{sup 5}-to {eta}{sup 1}-cyclopentadienyl ring slippage in catalysis was completed.

  3. Electromagnetic absorption and conductivity of organometallic TiOx-Py plasma compounds

    NASA Astrophysics Data System (ADS)

    González-Salgado, Francisco; Olayo, Maria Guadalupe; García-Rosales, Genoveva; Gómez, Lidia Maria; González-Torres, Maribel; Cruz, Guillermo J.

    2016-05-01

    Organometallic compounds made of titanium oxide (TiOx) and pyrrole (Py) were synthesized by plasma to combine the photoelectronic activity of TiO and Py in hybrid materials with potential use in photostimulated processes as photoelectronic devices in pollutant degradation or in solar photocollectors. The Ti precursors were based on titanium tetrapropoxide combined with Py in 1:1 mass ratio in a vacuum tubular glass reactor under resistive electrical glow discharges of water vapor plasmas. The TiOx-Py hybrid compounds with x in the 2.75-3.55 interval absorbed electromagnetic radiation in two regions with different intensities. The first and most intense one was from approximately 190 to 350 nm and the other from roughly 350 to 900 nm, which indicates that in the first interval, the TiO fraction dominates the absorption and that the activity of the second region belonged to Py segments. The electrical conductivity was in the (10-6-10-10) S/m interval with activation energy in the (0.015-2.42) eV range, depending on the reaction time and synthesis conditions.

  4. In silico characterization of a fourfold magnesium organometallic compound in PTCDA thin films.

    PubMed

    Zazza, Costantino; Sanna, Nico; Palma, Amedeo

    2009-12-31

    In this contribution, using first principles calculations within a density functional theory framework, we report, for the first time, evidence for the formation of a fourfold magnesium organometallic compound upon metal deposition on perylene-3,4,9,10-tetracarboxyl dianhydride (PTCDA) organic semiconductor. Current investigation clearly indicates that in the bulk of the organic crystallographic structure the magnesium atom mainly interacts with three PTCDA molecules. The reactive metal is bound both to carboxylic oxygen atoms of the anhydride-end moieties and to a perylene carbon atom which changes its hybridization state, from sp(2) to sp(3), in the presence of metal impurities. In turn, the analysis of the electronic structure of the reacted system prevalently reveals the formation of four covalent bonds, as a consequence of a weak charge transfer toward the organic material. Such a result confirms the capability of the PTCDA thin films to host metal atoms providing, inside their structural empty channels, a rather accessible and soft chemical environment. Interestingly, in the light of these findings and of previous works, a relationship between first ionization potential of the doping metal and the character of the newly formed chemical bonds is confirmed. PMID:19788293

  5. Theoretical Study of Indium Compounds of Interest for Organometallic Chemical Vapor Deposition

    NASA Technical Reports Server (NTRS)

    Cardelino, B. H.; Moore, C. E.; Cardelino, C. A.; Frazier, D. O.; Backmann, K. J.

    2000-01-01

    The structural. electronic and therinochemical properties of indium compounds which are of interest in halide transport and organometallic chemical vapor deposition processes have been studied by ab initio and statistical mechanics methods. The compounds reported include: indium halides and hydrides (InF, InCl, InCl3, InH, InH2, InH3); indium clusters (In2, In3); methylindium, dimethylindium, and their hydrogen derivatives [In(CH3), In(CH3)H, In(CH3)H2, In(CH3)2, In(CH3)2H]; dimethyl-indium dimer [In2(CH3)4], trimethyl-indium [In(CH3)3]; dehydrogenated methyl, dimethyl and trimethylindium [In(CH3)2CH2, In(CH3)CH2, In(CH2)], trimethylindium adducts with ammonia, trimethylamine and hydrazine [(CH3)3In:NH3, (CH3)3In:N(CH3)3, (CH3)3In:N(H2)N(H2)]; dimethylamino-indium and methylimino-indium [In(CH3)2(NH2), In(CH3)(NH)]; indium nitride and indium nitride dimer (InN, In2N2), indium phosphide, arsenide and antimonide ([InP, InAs, InSb). The predicted electronic properties are based on density functional theory calculations; the calculated thermodynamic properties are reported following the format of the JANAF (Joint Army, Navy, NASA, Air Force) Tables. Equilibrium compositions at two temperatures (298 and 1000 K) have been analyzed for groups of competing simultaneous reactions.

  6. Transition-metal organometallic compounds as cocatalysts in olefin polymerization with MgCl{sub 2}-supported catalysts

    SciTech Connect

    Galimberti, M.; Piemontesi, F.; Giannini, U.; Albizzati, E.

    1993-12-06

    Zirconium tetrabenzyl was used as the cocatalyst in olefin polymerization together with MgCl{sub 2}-supported titanium catalysts. Its behavior was compared with those of aluminum and titanium organometallic compounds. In propylene polymerization performed with a MgCl{sub 2}/TiCl{sub 4} catalyst containing ethyl benzoate as the internal donor and with tetrabenzylzirconium as the cocatalyst, a polypropylene with 93 as its isostatic index was obtained, without the need of any external donor. They present a tentative explanation, based on the study of the interaction between the different components of the catalytic system.

  7. Protective Actions of 17β-Estradiol and Progesterone on Oxidative Neuronal Injury Induced by Organometallic Compounds

    PubMed Central

    Ishihara, Yasuhiro; Takemoto, Takuya; Yamazaki, Takeshi

    2015-01-01

    Steroid hormones synthesized in and secreted from peripheral endocrine glands pass through the blood-brain barrier and play a role in the central nervous system. In addition, the brain possesses an inherent endocrine system and synthesizes steroid hormones known as neurosteroids. Increasing evidence shows that neuroactive steroids protect the central nervous system from various harmful stimuli. Reports show that the neuroprotective actions of steroid hormones attenuate oxidative stress. In this review, we summarize the antioxidative effects of neuroactive steroids, especially 17β-estradiol and progesterone, on neuronal injury in the central nervous system under various pathological conditions, and then describe our recent findings concerning the neuroprotective actions of 17β-estradiol and progesterone on oxidative neuronal injury induced by organometallic compounds, tributyltin, and methylmercury. PMID:25815107

  8. Rationalization of the inhibition activity of structurally related organometallic compounds against the drug target cathepsin B by DFT.

    PubMed

    Casini, Angela; Edafe, Fabio; Erlandsson, Mikael; Gonsalvi, Luca; Ciancetta, Antonella; Re, Nazzareno; Ienco, Andrea; Messori, Luigi; Peruzzini, Maurizio; Dyson, Paul J

    2010-06-21

    A series of organometallic compounds of general formula [(arene)M(PTA)(n)X(m)]Y (arene = eta(6)-C(10)H(14), eta-C(5)Me(5)); M = Ru(ii), Os(ii), Rh(iii) and Ir(iii); X = Cl, mPTA; Y = OTf, PF(6)) have been screened for their cytotoxicity and ability to inhibit cathepsin B in vitro, in comparison to the antimetastatic compound NAMI-A. The Ru and Os analogues and NAMI-A showed similar enzyme inhibition properties (with IC(50) values in the low muM range), whereas the Rh(iii) and Ir(iii) compounds were inactive. In order to build up a rational for the observed differences, DFT calculations of the metal complexes adducts with N-acetyl-l-cysteine-N'-methylamide, a mimic for the Cys residue in the cathepsin B active site, were performed to provide insights into binding thermodynamics in solution. Initial structure-activity relationships have been defined with the calculated binding energies of the M-S bonds correlating well with the observed inhibition properties of the compounds. PMID:20467693

  9. Phase Transition Enthalpy Measurements of Organic and Organometallic Compounds. Sublimation, Vaporization and Fusion Enthalpies From 1880 to 2015. Part 1. C1 - C10

    NASA Astrophysics Data System (ADS)

    Acree, William; Chickos, James S.

    2016-09-01

    A compendium of phase change enthalpies published in 2010 is updated to include the period 1880-2015. Phase change enthalpies including fusion, vaporization, and sublimation enthalpies are included for organic, organometallic, and a few inorganic compounds. Part 1 of this compendium includes organic compounds from C1 to C10. Part 2 of this compendium, to be published separately, will include organic and organometallic compounds from C11 to C192. Sufficient data are presently available to permit thermodynamic cycles to be constructed as an independent means of evaluating the reliability of the data. Temperature adjustments of phase change enthalpies from the temperature of measurement to the standard reference temperature, T = 298.15 K, and a protocol for doing so are briefly discussed.

  10. First-principles study of the organometallic S =1/2 kagome compound Cu(1,3-bdc)

    NASA Astrophysics Data System (ADS)

    Liu, Zheng; Mei, Jia-Wei; Liu, Feng

    2015-10-01

    Cu(1,3-benzenedicarboxylate) [Cu(1,3-bdc)] contains structurally perfect kagome planes formed by Cu2 + ions without the presence of diamagnetic defects. This organometallic compound should serve as a precious platform to explore quantum frustrated magnetism, yet the experimental results so far are mysterious, leading to questions such as, "Is Cu(1,3-bdc) just a trivial weak ferromagnet?" Using the density functional theory, we have systematically studied the electronic and magnetic properties of Cu(1,3-bdc), putting forth a theoretical basis to clarify this novel material. We present numerical evidence of a dominating antiferromagnetic (AFM) exchange between nearest-neighbor (NN) Cu2 + as experimentally extracted from the high-temperature susceptibility data. We further show that beyond the NN AFM exchange, the additional interactions in Cu(1,3-bdc) have similar strength as those in the well-studied kagome antiferromagnet, herbertsmithite, by designing a comparative study. In the end, we discuss our understanding of the phase transition and FM signals observed under low temperature.

  11. Effects of Reaction Conditions on the Properties of Spherical Silver Powders Synthesized by Reduction of an Organometallic Compound

    NASA Astrophysics Data System (ADS)

    Chiang, Ying-Jung; Wang, Sea-Fue; Lu, Chun-An; Lin, Hong-Ching

    2014-09-01

    Silver powders were synthesized by reducing a silver organometallic compound, silver 2-ethylhexanoate, with di- n-octylamine. The effects of preparation conditions on the characteristics of the powders were investigated. Silver powders prepared from silver 2-ethylhexanoate and di- n-octylamine in the ratio 2:1 (MA21) at 150°C for 3 h had the best characteristics (average particle size 277 nm, narrow particle-size distribution, high tap density of 4.0 g/cm3), and were also obtained in high yield (98%). Use of an excessive amount of di- n-octylamine resulted in intense thermolysis and a low yield of silver powders of irregular morphology with a wide particle-size distribution. As the proportion of silver 2-ethylhexanoate was increased, the silver powders obtained had a bimodal particle-size distribution and a relatively low tap density. Silver films seemed to have high resistivity when the temperature used for synthesis of the silver powders was too low or reaction time was insufficient. The electrical resistivities of silver films prepared from MA21 powders and sintered at 300°C and 500°C for 30 min were 3.8 × 10-6 Ω cm and 2.3 × 10-6 Ω cm, respectively, close to that of bulk silver.

  12. From carbanions to organometallic compounds: quantification of metal ion effects on nucleophilic reactivities.

    PubMed

    Corral-Bautista, Francisco; Klier, Lydia; Knochel, Paul; Mayr, Herbert

    2015-10-12

    The influence of the metal on the nucleophilic reactivities of indenyl metal compounds was quantitatively determined by kinetic investigations of their reactions with benzhydrylium ions (Ar2 CH(+) ) and structurally related quinone methides. With the correlation equation log k2 =sN (N+E), it can be derived that the ionic indenyl alkali compounds are 10(18) to 10(24) times more reactive (depending on the reference electrophile) than the corresponding indenyltrimethylsilane. PMID:25951612

  13. Aromatic amine N-oxide organometallic compounds: searching for prospective agents against infectious diseases.

    PubMed

    Rodríguez Arce, Esteban; Mosquillo, M Florencia; Pérez-Díaz, Leticia; Echeverría, Gustavo A; Piro, Oscar E; Merlino, Alicia; Coitiño, E Laura; Maríngolo Ribeiro, Camila; Leite, Clarice Q F; Pavan, Fernando R; Otero, Lucía; Gambino, Dinorah

    2015-08-28

    In search of prospective agents against infectious diseases, 1,1'-bis(diphenylphosphino)ferrocene pyridine-2-thiolato-1-oxide M(ii) hexafluorophosphate compounds [M(mpo)(dppf)](PF6), where M = palladium or platinum, were synthesized and fully characterized in the solid state and in solution using experimental and DFT computational techniques. The compounds are isomorphous and the M(ii) transition metal ions are in a nearly planar trapezoidal cis-coordination bound to the pyridine-2-thiolato-1-oxide (mpo) and to the 1,1'-bis(diphenylphosphino)ferrocene molecules, both acting as bidentate ligands. Both compounds showed high cytotoxic activity on Trypanosoma cruzi and Mycobacterium tuberculosis (MTB) and acceptable selectivities towards MTB, but good to excellent selectivity index values as anti-T. cruzi compounds. The inclusion of the ferrocene moiety (dppf ligand) improved the selectivity towards the parasite when compared to the previously reported [M(mpo)2] complexes. Related to the probable mechanism of action of the complexes, molecular docking studies on modelled T. cruzi NADH-fumarate reductase (TcFR) predicted that both be very good inhibitors of the enzyme. The effect of the compounds on the enzyme activity was experimentally confirmed using T. cruzi protein extracts. According to all obtained results, both [M(mpo)(dppf)](PF6) compounds could be considered prospective anti-trypanosomal agents that deserve further research. PMID:26203896

  14. Assessment of background concentrations of organometallic compounds (methylmercury, ethyllead and butyl- and phenyltin) in French aquatic environments.

    PubMed

    Cavalheiro, Joana; Sola, Cristina; Baldanza, Julie; Tessier, Emmanuel; Lestremau, François; Botta, Fabrizio; Preud'homme, Hugues; Monperrus, Mathilde; Amouroux, David

    2016-05-01

    The aim of this work is to estimate background concentrations of organometallic compounds, such as tributyltin (TBT), dibutyltin (DBT), monobutyltin (MBT), triphenyltin (TPhT), diphenyltin (DPhT), monophenyltin (MPhT), methylmercury (MeHg), inorganic mercury (iHg) and diethyllead (Et2Pb) in the aquatic environment at the French national scale. Both water and sediment samples were collected all over the country, resulting in 152 water samples and 123 sediment samples collected at 181 sampling points. Three types of surface water bodies were investigated: rivers (140 sites), lakes (19 sites) and coastal water (42 sites), spread along the 11 French river basins. The choice of sites was made on the basis of previous investigation results and the following target criteria: reference, urban sites, agricultural and industrial areas. The analytical method was properly validated for both matrices prior to analysis, resulting in low limits of quantification (LOQ), good precision and linearity in agreement with the Water Framework Directive demands. The results were first evaluated as a function of their river basins, type of surrounding pressure and water bodies. Later, background concentrations at the French national scale were established for both water and sediment matrices, as well as their threshold, i.e., the concentration that distinguishes background from anomalies or contaminations. Background concentrations in water are ranging between <0.04-0.14 ng Hg. L(-1) for MeHg, <0.14-2.10 ng Hg. L(-1) for iHg, <1.0-8.43 ng Pb. L(-1) for Et2Pb and 0.49-151 ng Sn. L(-1), <0.08-3.04 ng Sn. L(-1) and <0.08-0.25 ng Sn. L(-1) for MBT, DBT and TBT, respectively. For sediments, background concentrations were set as <0.09-1.11 ng Hg. g(-1) for MeHg, <0.06-24.3 ng Pb. g(-1) for Et2Pb and <1.4-13.4 ng Sn. g(-1), <0.82-8.54 ng Sn. g(-1), <0.25-1.16 ng Sn. g(-1) and <0.08-0.61 ng Sn. g(-1) for MBT, DBT, TBT and DPhT, respectively. TBT occurs in higher concentrations

  15. An Organometallic Compound which Exhibits a DNA Topology-Dependent One-Stranded Intercalation Mode.

    PubMed

    Ma, Zhujun; Palermo, Giulia; Adhireksan, Zenita; Murray, Benjamin S; von Erlach, Thibaud; Dyson, Paul J; Rothlisberger, Ursula; Davey, Curt A

    2016-06-20

    Understanding how small molecules interact with DNA is essential since it underlies a multitude of pathological conditions and therapeutic interventions. Many different intercalator compounds have been studied because of their activity as mutagens or drugs, but little is known regarding their interaction with nucleosomes, the protein-packaged form of DNA in cells. Here, using crystallographic methods and molecular dynamics simulations, we discovered that adducts formed by [(η(6) -THA)Ru(ethylenediamine)Cl][PF6 ] (THA=5,8,9,10-tetrahydroanthracene; RAED-THA-Cl[PF6 ]) in the nucleosome comprise a novel one-stranded intercalation and DNA distortion mode. Conversely, the THA group in fact remains solvent exposed and does not disrupt base stacking in RAED-THA adducts on B-form DNA. This newly observed DNA binding mode and topology dependence may actually be prevalent and should be considered when studying covalently binding intercalating compounds. PMID:27184539

  16. Organometallic Radiopharmaceuticals

    NASA Astrophysics Data System (ADS)

    Alberto, Roger

    Although molecular imaging agents have to be synthesized ultimately from aqueous solutions, organometallic complexes are becoming more and more important as flexible yet kinetically stable building blocks for radiopharmaceutical drug discovery. The diversity of ligands, targets, and targeting molecules related to these complexes is an essential base for finding novel, noninvasive imaging agents to diagnose and eventually treat widespread diseases such as cancer. This review article covers the most important findings toward these objectives accomplished during the past 3-4 years. The two major available organometallic building blocks will be discussed in the beginning together with constraints for market introduction as imposed by science and industry. Since targeting radiopharmaceuticals are a major focus of current research in molecular imaging, attempts toward so-called technetium essential radiopharmaceuticals will be briefly touched in the beginning followed by the main discussion about the labeling of targeting molecules such as folic acid, nucleosides, vitamins, carbohydrates, and fatty acids. At the end, some new strategies for drug discovery will be introduced together with results from organometallic chemistry in water. The majority of the new results have been achieved with the [99mTc(OH2)3(CO)3]+ complex which will, though not exclusively, be a focus of this review.

  17. Synthesis of a sugar-organometallic compound 1,1‧-difurfurylferrocene and its microwave preparation of carbon/iron oxide nanocomposite

    NASA Astrophysics Data System (ADS)

    Zhao, Shanyu; Cooper, Daniel C.; Xu, Haixun; Zhu, Pinghua; Suggs, J. William

    2013-01-01

    In order to synthesize a carbon-metal or metal oxide combination sphere, carbonaceous resource furfural 1 was introduced, which was nucleophilic treated with 1,1‧-dilithioferrocene 2 to form a sugar-organometallic compound: ferrocenyl monosaccharide derivative 1,1‧-difurfurylferrocene 3. 1,1‧-Difurfurylferrocene 3 can be hydrothermally treated in a microwave reactor to give 300-500 nm microspheres with the α-Fe2O3 or Fe3O4 nanocrystals formed on the surface, which may be favorable for new magnetic materials preparation or instead of iron with other metal ions, versatile carbon/metal composites will be possibly synthesized for catalysis, drug delivery and magnetic uses.

  18. Organometallic neptunium(III) complexes.

    PubMed

    Dutkiewicz, Michał S; Farnaby, Joy H; Apostolidis, Christos; Colineau, Eric; Walter, Olaf; Magnani, Nicola; Gardiner, Michael G; Love, Jason B; Kaltsoyannis, Nikolas; Caciuffo, Roberto; Arnold, Polly L

    2016-08-01

    Studies of transuranic organometallic complexes provide a particularly valuable insight into covalent contributions to the metal-ligand bonding, in which the subtle differences between the transuranium actinide ions and their lighter lanthanide counterparts are of fundamental importance for the effective remediation of nuclear waste. Unlike the organometallic chemistry of uranium, which has focused strongly on U(III) and has seen some spectacular advances, that of the transuranics is significantly technically more challenging and has remained dormant. In the case of neptunium, it is limited mainly to Np(IV). Here we report the synthesis of three new Np(III) organometallic compounds and the characterization of their molecular and electronic structures. These studies suggest that Np(III) complexes could act as single-molecule magnets, and that the lower oxidation state of Np(II) is chemically accessible. In comparison with lanthanide analogues, significant d- and f-electron contributions to key Np(III) orbitals are observed, which shows that fundamental neptunium organometallic chemistry can provide new insights into the behaviour of f-elements. PMID:27442286

  19. Organometallic neptunium(III) complexes

    NASA Astrophysics Data System (ADS)

    Dutkiewicz, Michał S.; Farnaby, Joy H.; Apostolidis, Christos; Colineau, Eric; Walter, Olaf; Magnani, Nicola; Gardiner, Michael G.; Love, Jason B.; Kaltsoyannis, Nikolas; Caciuffo, Roberto; Arnold, Polly L.

    2016-08-01

    Studies of transuranic organometallic complexes provide a particularly valuable insight into covalent contributions to the metal–ligand bonding, in which the subtle differences between the transuranium actinide ions and their lighter lanthanide counterparts are of fundamental importance for the effective remediation of nuclear waste. Unlike the organometallic chemistry of uranium, which has focused strongly on UIII and has seen some spectacular advances, that of the transuranics is significantly technically more challenging and has remained dormant. In the case of neptunium, it is limited mainly to NpIV. Here we report the synthesis of three new NpIII organometallic compounds and the characterization of their molecular and electronic structures. These studies suggest that NpIII complexes could act as single-molecule magnets, and that the lower oxidation state of NpII is chemically accessible. In comparison with lanthanide analogues, significant d- and f-electron contributions to key NpIII orbitals are observed, which shows that fundamental neptunium organometallic chemistry can provide new insights into the behaviour of f-elements.

  20. Synthesis of organometallic-based biologically active compounds: In vitro antibacterial, antifungal and cytotoxic properties of some sulfonamide incorporated ferrocences.

    PubMed

    Chohan, Zahid H

    2009-02-01

    Sulfonamides incorporated ferrocene (SIF) have been synthesized by the condensation reaction of sulfonamides (sulfanilamide, sulfathiazole or sulfamethaxazole) with 1,1'-diacetylferrocene. The synthesized compounds (SIF(1)-SIF(4)) have been characterized by their physical, spectral and analytical properties and have been screened for their in vitro antibacterial properties against pathogenic bacterial strains e.g., Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis Staphylococcus aureus and Salmonella typhi and for antifungal activity against Trichophyton longifusus, Candida albicans, Aspergillus flavus, Microsporum canis, Fusarium solani and Candida glaberata using Agar-well diffusion method. Most of the compounds showed good antibacterial activity whereas, all the compounds exhibited significant antifungal activity. Brine shrimp bioassay was also carried out for in vitro cytotoxic properties against Artemia salina. PMID:18608785

  1. Iron(III)-Salophene: An Organometallic Compound with Selective Cytotoxic and Anti-Proliferative Properties in Platinum-Resistant Ovarian Cancer Cells

    PubMed Central

    Singh, Rakesh K.; Strongin, Robert M.; McCourt, Carolyn K.; Brard, Laurent

    2008-01-01

    Background In this pioneer study to the biological activity of organometallic compound Iron(III)-salophene (Fe-SP) the specific effects of Fe-SP on viability, morphology, proliferation, and cell-cycle progression on platinum-resistant ovarian cancer cell lines were investigated. Methodology/Principal Findings Fe-SP displayed selective cytotoxicity against SKOV-3 and OVCAR-3 (ovarian epithelial adenocarcinoma) cell lines at concentrations between 100 nM and 1 µM, while the viability of HeLa cells (epithelial cervix adenocarcinoma) or primary lung or skin fibroblasts was not affected. SKOV-3 cells in contrast to fibroblasts after treatment with Fe-SP revealed apparent hallmarks of apoptosis including densely stained nuclear granular bodies within fragmented nuclei, highly condensed chromatin and chromatin fragmentation. Fe-SP treatment led to the activation of markers of the extrinsic (Caspase-8) and intrinsic (Caspase-9) pathway of apoptosis as well as of executioner Caspase-3 while PARP-1 was deactivated. Fe-SP exerted effects as an anti-proliferative agent with an IC50 value of 300 nM and caused delayed progression of cells through S-phase phase of the cell cycle resulting in a complete S-phase arrest. When intra-peritoneally applied to rats Fe-SP did not show any systemic toxicity at concentrations that in preliminary trials were determined to be chemotherapeutic relevant doses in a rat ovarian cancer cell model. Conclusion/Significance The present report suggests that Fe-SP is a potent growth-suppressing agent in vitro for cell lines derived from ovarian cancer and a potential therapeutic drug to treat such tumors in vivo. PMID:18509533

  2. Organometallic compounds of the lanthanides. 42/sup 1/ bis(dimethyloxyethane)lithium bis(cyclopentadienyl)bis(trimethylsilyl)lanthanide complexes

    SciTech Connect

    Schumann, H.; Nickel, S.; Loebel, J.; Pickardt, J.

    1988-09-01

    The trichlorides of Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu react with NaC/sub 5/H/sub 5/ in tetrahydrofuran in the presence of dimethoxyethane (dme) with formation of bis(cyclopentadienyl)lanthanide chloride complexes of the types (C/sub 5/H/sub 5/)/sub 2/Ln(/mu/-Cl)/sub 2/Na(dme). The reactions of these organolanthanide halide complexes with (trimethylsilyl)lithium in dme yield compounds of the type (Li(dme)/sub 2/)((C/sub 5/H/sub 5/)/sub 2/Ln(SiMe/sub 3/)/sub 2/) (Ln = Sm, Dy, Ho, Er, Tm, Lu). C/sub 5/H/sub 5//sub 2/Sm(/mu/-Cl)/sub 2/Na(dme) reacts with (trimethylgermyl)lithium in dme/pentane with formation of (Li(dme)/sub 3/)((C/sub 5/H/sub 5/)/sub 3/SmClSm(C/sub 5/H/sub 5/)/sub 3/) (7a.). The new compounds have been characterized by elemental analyses and IR and NMR spectra. The structure of (Li(dme)/sub 3/)(C/sub 5/H/sub 5/)/sub 3/SmClSm(C/sub 5/H/sub 5/)/sub 3/ (7a) has been elucidated through complete X-ray analysis. The crystals are monoclinic with a = 14.00 (1) /angstrom/, b = 13.38 (2) /angstrom/, c = 23.49 (3) /angstrom/, /beta/ = 93.37 (9)/degree/, space group P2/sub 1//n,Z = 4, and R = 0.0411 for 4671 reflections. The (Cp/sub 3/SmClSmCp/sub 3/)/sup /minus// anion consists of two Cp/sub 3/Sm units bridged by a chlorine atom with Sm-Cl distances of 2.827 (2) and 2.798 (2) /angstrom/.

  3. Organometallic Salts Generate Optical Second Harmonics

    NASA Technical Reports Server (NTRS)

    Marder, Seth R.; Perry, Joseph W.

    1991-01-01

    Series of organometallic salts exhibit large second-order dielectric susceptibilities, as evidenced by generation of second harmonics when illuminated at visible and near-infrared wavelengths. Investigations of these and related compounds continue with view toward development of materials for use as optical second-harmonic generators, electro-optical modulators, optical switches, piezoelectric sensors, and parametric crystals.

  4. Organometallic Chemistry of Molybdenum.

    ERIC Educational Resources Information Center

    Lucas, C. Robert; Walsh, Kelly A.

    1987-01-01

    Suggests ways to avoid some of the problems students have learning the principles of organometallic chemistry. Provides a description of an experiment used in a third-year college chemistry laboratory on molybdenum. (TW)

  5. Detection of toxic organometallic complexes in wastewaters using algal assays.

    PubMed

    Wong, S L; Nakamoto, L; Wainwright, J F

    1997-05-01

    Chlorella (a unicellular green alga) and Cladophora (a filamentous alga) were used in algal assays to identify the presence and toxicity of organometallic complexes in four industrial wastewaters. Toxicities of inorganic Pb and organometallic compounds (trimethyl, tetramethyl and tetraethyl leads, cacodylic acid and Cu-picolinate) were examined, using algal cells grown in 10% BBM solution. Inorganic Pb and organometallic compounds altered the fine structure of Chlorella cells in a distinguishable manner. X-ray microanalysis revealed that organometallic compounds accumulated in the neutral lipids of Cladophora cells. By applying the above techniques to the wastewater assays, two of the four wastewaters tested were found to contain organometallic complexes. Wastewater from a chemical company contained only traces of organo-Cu, but one mining effluent contained significant quantities of organo-Cu and organo-Pb, and traces of organo-Cr and organo-Tl (thallium). These studies suggest that X-ray microanalysis of algae may be a useful tool in identifying aquatic systems contaminated with metals and organometallic compounds. PMID:9175500

  6. Coupling of a gas chromatograph to a simultaneous-detection inductively coupled plasma mass spectrograph for speciation of organohalide and organometallic compounds

    SciTech Connect

    Barnes, James H.; Schilling, G; Sperline, Roger; Denton, M Bonner B.; Young, Erick T.; Barinaga, Charles J.; Koppenaal, David W.; Hieftje, Gary M.

    2004-06-01

    A gas chromatograph (GC) has been coupled to an inductively coupled plasma Mattauch-Herzog geometry mass spectrograph (ICP-MHMS) equipped with a novel detector array. In its current state of development the detector array, termed the focal plan camera (FPC), permits the simultaneous monitoring of up to 15 m/z values. A heated line was used to transfer the capillary-column effluent from the GC to the ICP torch, though due to instrument operating conditions, the transfer line was terminated 50 mm ahead of the ICP torch. Minimal tailing was observed, with the most severe effect seen for high-boiling analytes. With the coupling, absolute limits of detection are in the tens to hundreds of femtogram regime for organometallic species and in the single pictogram regime for halogenated hydrocarbons.

  7. Sterically Hindered Square-Planar Nickel(II) Organometallic Complexes: Preparation, Characterization, and Substitution Behavior

    ERIC Educational Resources Information Center

    Martinez, Manuel; Muller, Guillermo; Rocamora, Merce; Rodriguez, Carlos

    2007-01-01

    The series of experiments proposed for advanced undergraduate students deal with both standard organometallic preparative methods in dry anaerobic conditions and with a kinetic study of the mechanisms operating in the substitution of square-planar complexes. The preparation of organometallic compounds is carried out by transmetallation or…

  8. Synthesis of functionalized materials using aryloxo-organometallic compounds toward spinel-like MM'2O4 (M = Ba2+, Sr2+; M' = In3+, Al3+) double oxides.

    PubMed

    John, Łukasz; Kosińska-Klähn, Magdalena; Jerzykiewicz, Lucjan B; Kępiński, Leszek; Sobota, Piotr

    2012-09-17

    The predesigned single-source precursors [Ba{(μ-ddbfo)(2)InMe(2)}(2)] (1), [Me(2)In(μ-ddbfo)](2) (2), [Sr{(μ-ddbfo)(2)AlMe(2)}(2)] (4), and [Me(2)Al(μ-ddbfo)](2) (5) (ddbfoH = 2,3-dihydro-2,2-dimethylbenzofuran-7-ol) for spinel-like double oxides and group 13 oxide materials were prepared via the direct reaction of the homoleptic aryloxide [M(ddbfoH)(4)](ddbfo)(2)·ddbfoH (M = Ba(2+), Sr(2+) (3)) and InMe(3) or AlMe(3) in toluene. In all of the reactions, there was an organometallic-driven abstraction of the OH protons from the 7-benzofuranols in the Ba(2+) and Sr(2+) cation sphere. All compounds were characterized by elemental analysis, (1)H NMR, and FT-IR spectroscopy. In addition, the molecular structures of 1, 2, and 3 were determined by single-crystal X-ray diffraction. The oxide products derived from the compounds mentioned above were studied using elemental analysis, Raman spectroscopy, X-ray powder diffraction, and scanning and transmission electron microscopy equipped with an energy-dispersive spectrometer. Moreover, their specific surface area and mesopore size distribution were evaluated using nitrogen porosimetry. Preliminary investigations of the Eu-doped SrAl(2)O(4) and In(2)O(3) phosphors revealed that the oxides obtained could be considered as matrices for lanthanide ions. PMID:22931100

  9. Precursor approach to lanthanide dioxo monocarbodiimides Ln2O2CN2 (Ln=Y, Ho, Er, Yb) by insertion of CO2 into organometallic Ln-N compounds.

    PubMed

    Zeuner, Martin; Pagano, Sandro; Schnick, Wolfgang

    2008-01-01

    We present two organometallic precursor approaches leading to the hitherto-unknown dioxo monocarbodiimides (Ln(2)O(2)CN(2)) of the late lanthanides Ho, Er, and Yb as well as yttrium. One involves insertion of CO(2), and the other one is a straightforward route using a molecular single-source precursor. To this end the reactivity of the activated amido lanthanide compound [(Cp(2)ErNH(2))(2)] towards carbon dioxide absorption under supercritical conditions was studied. Selective insertion of CO(2) into the amido complex yielded the single-source precursor [Er(2)(O(2)CN(2)H(4))Cp(4)], which was characterized by vibrational spectroscopy and thermal and elemental analyses. Ammonolysis of this amorphous compound at 700 degrees C affords Er(2)O(2)CN(2). To gain deeper insight into the structural characteristics of the amorphous precursor, a similar molecular carbamato complex was synthesized and fully characterized. X-ray structure analysis of the dimeric complex [Cp(4)Ho(2){mu-eta(1):eta(2)-OC(OtBu)NH}] shows an unusual bonding mode of the tert-butylcarbamate ligand, which acts as both a bridging and side-on chelating group. Ammonolysis of this compound also yielded dioxo monocarbodiimides, and therefore the crystalline carbamato complex turned out to be an alternative precursor for the straightforward synthesis of Ln(2)O(2)CN(2). Analogously, the dioxo monocarbodiimides of Y, Ho, Er, and Yb were synthesized by this route. The crystal structures were determined from X-ray powder diffraction data and refined by the Rietveld method (Ln=Ho, Er). Further spectroscopic characterization and elemental analysis evidenced the existence of phase-pure products. The dioxo monocarbodiimides of holmium and erbium crystallize in the trigonal space group P[over]3m1. According to X-ray powder diffraction, they adopt the Ln(2)O(2)CN(2) (Ln=Ce-Gd) structure type. PMID:18058884

  10. Preparation of activated carbons with mesopores by use of organometallics

    SciTech Connect

    Yamada, Yoshio; Yoshizawa, Noriko; Furuta, Takeshi

    1996-12-31

    Activated carbons are commercially produced by steam or CO{sub 2} activation of coal, coconut shell and so on. In general the carbons obtained give pores with a broad range of distribution. The objective of this study was to prepare activated carbons from coal by use of various organometallic compounds. The carbons were evaluated for pore size by nitrogen adsorption experiments.

  11. Organometallic Chemistry. Final Progress Report

    SciTech Connect

    2003-07-14

    The Gordon Research Conference (GRC) on Organometallic Chemistry was held at Salve Regina, Newport, Rhode Island, 7/21-26/02. Emphasis was placed on current unpublished research and discussion of the future target areas in this field.

  12. Organometallics Roundtable 2011

    SciTech Connect

    Gladysz, John A.; Ball, Zachary T.; Bertrand, Guy; Blum, Suzanne A.; Dong, Vy M.; Dorta, Reto; Hahn, F. Ekkehardt; Humphrey, Mark; Jones, William D.; Klosin, Jerzy; Manners, Ian; Marks, Tobin J.; Mayer, James M.; Rieger, Bernhard; Ritter, Joachim C.; Sattelberger, Alfred P.; Schomaker, Jennifer M.; Wing-Wah Yam, Vivian

    2012-01-09

    We are living in an era of unprecedented change in academic, industrial, and government-based research worldwide, and navigating these rough waters requires "all hands on deck". Toward this end, Organometallics has assembled a panel of seventeen experts who share their thoughts on a variety of matters of importance to our field. In constituting this panel, an attempt was made to secure representation from a number of countries and career stages, as well as from industry. We were fortunate that so many busy experts could take the time to spend with us. The following pages constitute an edited transcript of the panel discussion held on August 29, 2011, which was structured around the 10 questions summarized in the side bar and repeated below.

  13. Hydrogenation properties of nanostructured Ti2Ni-based alloys and nanocomposites

    NASA Astrophysics Data System (ADS)

    Balcerzak, M.; Jakubowicz, J.; Kachlicki, T.; Jurczyk, M.

    2015-04-01

    Mechanical alloying and annealing at 1023 K for 0.5 h under an argon atmosphere were used to prepare Ti2Ni-based nanocrystalline alloys and their nanocomposites. Ti2Ni alloy was chemically modified by Pd and multi-walled carbon nanotubes. An objective of the present study is to provide data on hydrogenation properties of Ti2Ni-based alloys and compounds containing Pd and/or multi-walled carbon nanotubes. Alloys and composites were characterized by X-ray diffraction, scanning electron microscopy equipped with an electron energy dispersive spectrometer, transmission electron microscopy, atomic force microscopy to evaluate phase composition, crystal structure, grain size, particle morphology and distribution of catalyst element. Hydrogenation/dehydrogenation properties and hydriding kinetics of materials were measured using a Sievert's apparatus. Hydrogenation properties of nanostructured Ti2Ni-based alloy and Ti2Ni-based nanocomposites were compared with those of the binary Ti2Ni compound. In present work we shown how mechanical alloying method and chemical modification by Pd and MWCNTs affected hydrogen storage properties of Ti2Ni alloy. The highest hydrogen capacity obtained for nanostructured Ti2Ni + Pd alloy equaled 2.1 wt.%. Up to our knowledge it is the highest hydrogen storage capacity obtained so far for Ti2Ni-based materials.

  14. NEW APPLICATIONS OF LC-MS AND LC-MS2 TOWARD UNDERSTANDING THE ENVIRONMENTAL FATE OF ORGANOMETALLICS

    EPA Science Inventory

    Over the last 40 years, many organometallic compounds have been synthesized and used in a variety of consumer, agricultural, and industrial products. Including wastewater effluents, leaching, and direct land and water applications, there are many pathways that can disperse organo...

  15. Use of ionic liquids as coordination ligands for organometallic catalysts

    DOEpatents

    Li, Zaiwei; Tang, Yongchun; Cheng; Jihong

    2009-11-10

    Aspects of the present invention relate to compositions and methods for the use of ionic liquids with dissolved metal compounds as catalysts for a variety of chemical reactions. Ionic liquids are salts that generally are liquids at room temperature, and are capable of dissolving a many types of compounds that are relatively insoluble in aqueous or organic solvent systems. Specifically, ionic liquids may dissolve metal compounds to produce homogeneous and heterogeneous organometallic catalysts. One industrially-important chemical reaction that may be catalyzed by metal-containing ionic liquid catalysts is the conversion of methane to methanol.

  16. Organometallic Chemistry and Catalysis in Industry.

    ERIC Educational Resources Information Center

    Parshall, George W.; Putscher, Richard E.

    1986-01-01

    Traces the growth in the industrial usage of organometallic chemistry from 1950 to 1977, pointing out that this growth involved the production of commodity chemicals. Indicates that one of the early successes of organometallic chemistry was the discovery of ethylene polymerization catalysts. (JN)

  17. Anticancer Organometallic Osmium(II)-p-cymene Complexes.

    PubMed

    Păunescu, Emilia; Nowak-Sliwinska, Patrycja; Clavel, Catherine M; Scopelliti, Rosario; Griffioen, Arjan W; Dyson, Paul J

    2015-09-01

    Osmium compounds are attracting increasing attention as potential anticancer drugs. In this context, a series of bifunctional organometallic osmium(II)-p-cymene complexes functionalized with alkyl or perfluoroalkyl groups were prepared and screened for their antiproliferative activity. Three compounds from the series display selectivity toward cancer cells, with moderate cytotoxicity observed against human ovarian carcinoma (A2780) cells, whereas no cytotoxicity was observed on non-cancerous human embryonic kidney (HEK-293) cells and human endothelial (ECRF24) cells. Two of these three cancer-cell-selective compounds induce cell death largely via apoptosis and were also found to disrupt vascularization in the chicken embryo chorioallantoic membrane (CAM) model. Based on these promising properties, these compounds have potential clinical applications. PMID:26190176

  18. Angle-resolved spectroscopy study of Ni-based superconductor SrNi2As2

    NASA Astrophysics Data System (ADS)

    Zeng, L.-K.; Richard, P.; van Roekeghem, A.; Yin, J.-X.; Wu, S.-F.; Chen, Z. G.; Wang, N. L.; Biermann, S.; Qian, T.; Ding, H.

    2016-07-01

    We performed an angle-resolved photoemission spectroscopy study of the Ni-based superconductor SrNi2As2 . Electron and hole Fermi surface pockets are observed, but their different shapes and sizes lead to very poor nesting conditions. The experimental electronic band structure of SrNi2As2 is in good agreement with first-principles calculations after a slight renormalization (by a factor 1.1), confirming the picture of Hund's exchange-dominated electronic correlations decreasing with increasing filling of the 3 d shell in the Fe-, Co-, and Ni-based compounds. These findings emphasize the importance of Hund's coupling and 3 d -orbital filling as key tuning parameters of electronic correlations in transition-metal pnictides.

  19. Organometallic chemistry meets crystal engineering to give responsive crystalline materials.

    PubMed

    Bacchi, A; Pelagatti, P

    2016-01-25

    Dynamically porous crystalline materials have been obtained by engineering organometallic molecules. This feature article deals with organometallic wheel-and-axle compounds, molecules with two relatively bulky groups (wheels) connected by a linear spacer. The wheels are represented by half-sandwich Ru(ii) moieties, while the spacer can be covalent or supramolecular in character. Covalent spacers are obtained using divergent bidentate ligands connecting two [(arene)RuX2] groups. Supramolecular spacers are instead obtained by exploiting the dimerization of COOH or C(O)NH2 groups appended to N-based ligands. A careful choice of ligand functional groups and X ligands leads to the isolation of crystalline materials with remarkable host-guest properties, evidenced by the possibility of reversibly capturing/releasing volatile guests through heterogenous solid-gas reactions. Structural correlations between the crystalline arrangement of the apohost and the host-guest compounds allow us to envisage the structural path followed by the system during the exchange processes. PMID:26673552

  20. Combinatorial sythesis of organometallic materials

    DOEpatents

    Schultz, Peter G.; Xiang, Xiaodong; Goldwasser, Isy

    2002-07-16

    Methods and apparatus for the preparation and use of a substrate having an array of diverse materials in predefined regions thereon. A substrate having an array of diverse materials thereon is generally prepared by delivering components of materials to predefined regions on a substrate, and simultaneously reacting the components to form at least two materials. Materials which can be prepared using the methods and apparatus of the present invention include, for example, covalent network solids, ionic solids and molecular solids. More particularly, materials which can be prepared using the methods and apparatus of the present invention include, for example, inorganic materials, intermetallic materials, metal alloys, ceramic materials, organic materials, organometallic materials, non-biological organic polymers, composite materials (e.g., inorganic composites, organic composites, or combinations thereof), etc. Once prepared, these materials can be screened for useful properties including, for example, electrical, thermal, mechanical, morphological, optical, magnetic, chemical, or other properties. Thus, the present invention provides methods for the parallel synthesis and analysis of novel materials having useful properties.

  1. Patterns in Organometallic Chemistry with Application in Organic Synthesis.

    ERIC Educational Resources Information Center

    Schwartz, Jeffrey; Labinger, Jay A.

    1980-01-01

    Of interest in this discussion of organometallic complexes are stoichiometric or catalytic reagents for organic synthesis in the complex transformations observed during synthesis for transition metal organometallic complexes. Detailed are general reaction types from which the chemistry or many transition metal organometallic complexes can be…

  2. Organometallic Antitumour Agents with Alternative Modes of Action

    NASA Astrophysics Data System (ADS)

    Casini, Angela; Hartinger, Christian G.; Nazarov, Alexey A.; Dyson, Paul J.

    The therapeutic index of drugs that target DNA, a ubiquitous target present in nearly all cells, is low. Nevertheless, DNA has remained the primary target for medicinal chemists developing metal-based anticancer drugs, although DNA has been essentially abandoned in favour of non-genomic targets by medicinal chemists developing organic drugs. A number of organometallic drugs that target proteins/enzymes have been developed and these compounds, based on ruthenium, osmium and gold, are described in this chapter. Targets include cathepsin B, thioredoxin reductases, multidrug resistance protein (Pgp), glutathione S-transferases and kinases. It is found that compounds that inhibit these various targets are active against metastatic tumours, or tumours that are resistant to classical DNA damaging agents such as cisplatin, and therefore offer considerable potential in clinical applications.

  3. Automated building of organometallic complexes from 3D fragments.

    PubMed

    Foscato, Marco; Venkatraman, Vishwesh; Occhipinti, Giovanni; Alsberg, Bjørn K; Jensen, Vidar R

    2014-07-28

    A method for the automated construction of three-dimensional (3D) molecular models of organometallic species in design studies is described. Molecular structure fragments derived from crystallographic structures and accurate molecular-level calculations are used as 3D building blocks in the construction of multiple molecular models of analogous compounds. The method allows for precise control of stereochemistry and geometrical features that may otherwise be very challenging, or even impossible, to achieve with commonly available generators of 3D chemical structures. The new method was tested in the construction of three sets of active or metastable organometallic species of catalytic reactions in the homogeneous phase. The performance of the method was compared with those of commonly available methods for automated generation of 3D models, demonstrating higher accuracy of the prepared 3D models in general, and, in particular, a much wider range with respect to the kind of chemical structures that can be built automatically, with capabilities far beyond standard organic and main-group chemistry. PMID:24998944

  4. Organometallic vapor phase epitaxial growth of InP using new phosphorus sources

    NASA Astrophysics Data System (ADS)

    Larsen, C. A.; Chen, C. H.; Kitamura, M.; Stringfellow, G. B.; Brown, D. W.; Robertson, A. J.

    1986-06-01

    Two organophosphorus compounds, isobutylphosphine and tertiarybutylphosphine, have been investigated for their possible use as precursors in the organometallic vapor phase epitaxy process. They are the first nonhydride compounds to be used as phosphorus sources. Pyrolysis studies show that the first decomposition products are phosphine and various organic compounds. The phosphine then pyrolyzes to give phosphorus. The materials are less pyrophoric and less toxic than phosphine, and so are safer to use. The compounds have been used to grow epitaxial layers of InP on InP and GaAs substrates. The layers exhibit photoluminescence and electrical properties which are similar to those of layers grown with phosphine.

  5. Noninvasive Fluid Level Sensor for Organometallic Sources

    NASA Technical Reports Server (NTRS)

    Gerdes, W.

    1986-01-01

    Two ultrasonic methods available for measuring level of organometallic liquid in stainless-steel (or other homogeneous solid) container. Methods require no disassembly or weighing of container. Commercially available ultrasonic flaw detectors, some of which have digital readouts and computer interfaces, used in techniques. Both methods used in crystal growth to determine level of liquids contained in sealed, opaque containers.

  6. Advances in organometallic synthesis with mechanochemical methods.

    PubMed

    Rightmire, Nicholas R; Hanusa, Timothy P

    2016-02-14

    Solvent-based syntheses have long been normative in all areas of chemistry, although mechanochemical methods (specifically grinding and milling) have been used to good effect for decades in organic, and to a lesser but growing extent, inorganic coordination chemistry. Organometallic synthesis, in contrast, represents a relatively underdeveloped area for mechanochemical research, and the potential benefits are considerable. From access to new classes of unsolvated complexes, to control over stoichiometries that have not been observed in solution routes, mechanochemical (or 'M-chem') approaches have much to offer the synthetic chemist. It has already become clear that removing the solvent from an organometallic reaction can change reaction pathways considerably, so that prediction of the outcome is not always straightforward. This Perspective reviews recent developments in the field, and describes equipment that can be used in organometallic synthesis. Synthetic chemists are encouraged to add mechanochemical methods to their repertoire in the search for new and highly reactive metal complexes and novel types of organometallic transformations. PMID:26763151

  7. Cytotoxic properties of a new organometallic platinum(II) complex and its gold(I) heterobimetallic derivatives.

    PubMed

    Serratrice, Maria; Maiore, Laura; Zucca, Antonio; Stoccoro, Sergio; Landini, Ida; Mini, Enrico; Massai, Lara; Ferraro, Giarita; Merlino, Antonello; Messori, Luigi; Cinellu, Maria Agostina

    2016-01-14

    A novel platinum(ii) organometallic complex, [Pt(pbi)(Me)(DMSO)], bearing the 2-(2'-pyridyl)-benzimidazole (pbiH) ligand, was synthesized and fully characterized. Interestingly, the reaction of this organometallic platinum(ii) complex with two distinct gold(i) phosphane compounds afforded the corresponding heterobimetallic derivatives with the pbi ligand bridging the two metal centers. The antiproliferative properties in vitro of [Pt(pbi)(Me)(DMSO)] and its gold(i) derivatives as well as those of the known coordination platinum(ii) and palladium(ii) complexes with the same ligand, of the general formula [MCl2(pbiH)], were comparatively evaluated against A2780 cancer cells, either sensitive or resistant to cisplatin. A superior biological activity of the organometallic compound clearly emerged compared to the corresponding platinum(ii) complex; the antiproliferative effects are further enhanced upon attaching the gold(i) triphenylphosphine moiety to the organometallic Pt compound. Remarkably, these novel metal species are able to overcome nearly complete resistance to cisplatin. Significant mechanistic insight into the study compounds was gained after investigating their reactions with a few representative biomolecules by electrospray mass spectrometry and X-ray crystallography. The obtained results are comprehensively discussed. PMID:26609781

  8. Preparation of uranium compounds

    DOEpatents

    Kiplinger, Jaqueline L; Montreal, Marisa J; Thomson, Robert K; Cantat, Thibault; Travia, Nicholas E

    2013-02-19

    UI.sub.3(1,4-dioxane).sub.1.5 and UI.sub.4(1,4-dioxane).sub.2, were synthesized in high yield by reacting turnings of elemental uranium with iodine dissolved in 1,4-dioxane under mild conditions. These molecular compounds of uranium are thermally stable and excellent precursor materials for synthesizing other molecular compounds of uranium including alkoxide, amide, organometallic, and halide compounds.

  9. A ferroelectric olefin-copper(I) organometallic polymer with flexible organic ligand (R)-MbVBP

    NASA Astrophysics Data System (ADS)

    Wang, Guo-Xi; Xing, Zheng; Chen, Li-Zhuang; Han, Guang-Fan

    2015-07-01

    Hydrothermal treatment of (R)-2-methyl-1,4-bis(4-vinylbenzyl)piperazine [(R)-MbVBP] and CuCl afforded a novel olefin-copper(I) coordination compound. Introducing the flexible ligand (R)-MbVBP allowed the olefin-copper(I) organometallic compound to crystallize in a polar point group P21. The compound was ferroelectric, and its electric hysteresis loop showed a remnant polarization (Pr) of 0.13-0.32 μC cm-2 and a coercive field (Ec) of 3.5-11 kV cm-1.

  10. Mechanistic study of organometallic vapor phase epitaxy

    SciTech Connect

    Stringfellow, G.B.

    1990-12-31

    Only AsH{sub 3} and PH{sub 3} have been used as the group V source molecules for organometallic vapor phase epitaxy (OMVPE) of III/V semiconductors until recently, since they have been the only precursors yielding device quality materials. This paper reviews recent work on the pyrolysis of individual organometallic molecules, with emphasis on the group V sources, including: (1) the methylarsines, di- and tri-methylarsine, (2) the ethylarsines, mono-, di-, and tri-ethylarsine, and (3) the singly substituted tertiarybutyl arsine and phosphine molecules. The pyrolysis and growth reactions occurring when both group III and group V precursors are present simultaneously, i.e., the reactions occuring during OMVPE growth of several III/V semiconductors, are also briefly reviewed.

  11. Mechanistic study of organometallic vapor phase epitaxy

    SciTech Connect

    Stringfellow, G.B.

    1990-01-01

    Only AsH{sub 3} and PH{sub 3} have been used as the group V source molecules for organometallic vapor phase epitaxy (OMVPE) of III/V semiconductors until recently, since they have been the only precursors yielding device quality materials. This paper reviews recent work on the pyrolysis of individual organometallic molecules, with emphasis on the group V sources, including: (1) the methylarsines, di- and tri-methylarsine, (2) the ethylarsines, mono-, di-, and tri-ethylarsine, and (3) the singly substituted tertiarybutyl arsine and phosphine molecules. The pyrolysis and growth reactions occurring when both group III and group V precursors are present simultaneously, i.e., the reactions occuring during OMVPE growth of several III/V semiconductors, are also briefly reviewed.

  12. Segregation of impurities at γ' (L12) / γ (fcc) interfaces in a Ni-based superalloy

    NASA Astrophysics Data System (ADS)

    Tafen, De Nyago; Gao, Michael

    2011-03-01

    One of the most technologically advanced energy conversion devices is the gas turbine used in aerospace jet engines and gas- fired land-based turbines for electricity generation, fabricated from Ni-based superalloys. However, these materials lack of long- term mechanical and microstructure stability, which is largely due to an excessive coarsening of γ ' that can cause substantial loss of creep resistance and mechanical instability at high temperatures. Theoretical prediction of the creep rate of these important compounds is very imperative, but yet is extremely challenging. Interfacial energy is one of the most important factors that control the coarsening kinetics of these important phases. It indirectly determines the creep resistance of the alloy through the coarsening rate of the strengthening precipitate phase. In this talk, we will present the results of various γ ' / γ interfaces of a Ni-based superalloy obtained using DFT calculations. Then, we will discuss the segregation of impurities at these interfaces. Minor alloying elements in superalloys can alter the interfacial energy between γ and γ ' , and change the strength behavior of the alloy. Alloying elements or impurity species can segregate to interfaces. A favorable segregation would result in enhancing the interfacial cohesion and thus lower the energy.

  13. In Situ Observation of Active Oxygen Species in Fe-Containing Ni-Based Oxygen Evolution Catalysts: The Effect of pH on Electrochemical Activity.

    PubMed

    Trześniewski, Bartek J; Diaz-Morales, Oscar; Vermaas, David A; Longo, Alessandro; Bras, Wim; Koper, Marc T M; Smith, Wilson A

    2015-12-01

    Ni-based oxygen evolution catalysts (OECs) are cost-effective and very active materials that can be potentially used for efficient solar-to-fuel conversion process toward sustainable energy generation. We present a systematic spectroelectrochemical characterization of two Fe-containing Ni-based OECs, namely nickel borate (Ni(Fe)-B(i)) and nickel oxyhydroxide (Ni(Fe)OOH). Our Raman and X-ray absorption spectroscopy results show that both OECs are chemically similar, and that the borate anions do not play an apparent role in the catalytic process at pH 13. Furthermore, we show spectroscopic evidence for the generation of negatively charged sites in both OECs (NiOO(-)), which can be described as adsorbed "active oxygen". Our data conclusively links the OER activity of the Ni-based OECs with the generation of those sites on the surface of the OECs. The OER activity of both OECs is strongly pH dependent, which can be attributed to a deprotonation process of the Ni-based OECs, leading to the formation of the negatively charged surface sites that act as OER precursors. This work emphasizes the relevance of the electrolyte effect to obtain catalytically active phases in Ni-based OECs, in addition to the key role of the Fe impurities. This effect should be carefully considered in the development of Ni-based compounds meant to catalyze the OER at moderate pHs. Complementarily, UV-vis spectroscopy measurements show strong darkening of those catalysts in the catalytically active state. This coloration effect is directly related to the oxidation of nickel and can be an important factor limiting the efficiency of solar-driven devices utilizing Ni-based OECs. PMID:26544169

  14. Tuning Electronic Structure, Redox, and Photophysical Properties in Asymmetric NIR-Absorbing Organometallic BODIPYs.

    PubMed

    Zatsikha, Yuriy V; Maligaspe, Eranda; Purchel, Anatolii A; Didukh, Natalia O; Wang, Yefeng; Kovtun, Yuriy P; Blank, David A; Nemykin, Victor N

    2015-08-17

    Stepwise modification of the methyl groups at the α positions of BODIPY 1 was used for preparation of a series of mono- (2, 4, and 6) and diferrocene (3) substituted donor-acceptor dyads in which the organometallic substituents are fully conjugated with the BODIPY π system. All donor-acceptor complexes have strong absorption in the NIR region and quenched steady-state fluorescence, which can be partially restored upon oxidation of organometallic group(s). X-ray crystallography of complexes 2-4 and 6 confirms the nearly coplanar arrangement of the ferrocene groups and the BODIPY π system. Redox properties of the target systems were studied using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). It was found that the first oxidation process in all dyads is ferrocene centered, while the separation between the first and the second ferrocene-centered oxidation potentials in diferrocenyl-containing dyad 3 is ∼150 mV. The density functional theory-polarized continuum model (DFT-PCM) and time-dependent (TD) DFT-PCM methods were used to investigate the electronic structure as well as explain the UV-vis and redox properties of organometallic compounds 2-4 and 6. TDDFT calculations allow for assignment of the charge-transfer and π → π* transitions in the target compounds. The excited state dynamics of the parent BODIPY 1 and dyads 2-4 and 6 were investigated using time-resolved transient spectroscopy. In all organometallic dyads 2-4 and 6 the initially excited state is rapidly quenched by electron transfer from the ferrocene ligand. The lifetime of the charge-separated state was found to be between 136 and 260 ps and demonstrates a systematic dependence on the electronic structure and geometry of BODIPYs 2-4 and 6. PMID:26220063

  15. The water soluble ruthenium(II) organometallic compound [Ru(p-cymene)(bis(3,5 dimethylpyrazol-1-yl)methane)Cl]Cl suppresses triple negative breast cancer growth by inhibiting tumor infiltration of regulatory T cells.

    PubMed

    Montani, Maura; Pazmay, Gretta V Badillo; Hysi, Albana; Lupidi, Giulio; Pettinari, Riccardo; Gambini, Valentina; Tilio, Martina; Marchetti, Fabio; Pettinari, Claudio; Ferraro, Stefano; Iezzi, Manuela; Marchini, Cristina; Amici, Augusto

    2016-05-01

    Ruthenium compounds have become promising alternatives to platinum drugs by displaying specific activities against different cancers and favorable toxicity and clearance properties. Here, we show that the ruthenium(II) complex [Ru(p-cymene)(bis(3,5-dimethylpyrazol-1-yl)methane)Cl]Cl (UNICAM-1) exhibits potent in vivo antitumor effects. When administered as four-dose course, by repeating a single dose (52.4mgkg-1) every three days, UNICAM-1 significantly reduces the growth of A17 triple negative breast cancer cells transplanted into FVB syngeneic mice. Pharmacokinetic studies indicate that UNICAM-1 is rapidly eliminated from kidney, liver and bloodstream thanks to its high hydrosolubility, exerting excellent therapeutic activity with minimal side effects. Immunohistological analysis revealed that the efficacy of UNICAM-1, mainly relies on its capacity to reverse tumor-associated immune suppression by significantly reducing the number of tumor-infiltrating regulatory T cells. Therefore, UNICAM-1 appears very promising for the treatment of TNBC. PMID:27038531

  16. Multifunctionality of organometallic quinonoid metal complexes: surface chemistry, coordination polymers, and catalysts.

    PubMed

    Kim, Sang Bok; Pike, Robert D; Sweigart, Dwight A

    2013-11-19

    rhodium complex showed catalytic activity in Suzuki-Miyaura type reaction. As a result of the excellent stability of the homogeneous catalyst [(quinone)Rh(COD)](-) in water, we also successfully demonstrated catalyst recycling in 1,2- and 1,4-addition reactions. The compound [(quinone)Ir(COD)](-) showed significantly poorer catalytic activity in 1,4-addition reactions. Following upon the excellent coordination ability of the quinonoid rhodium complexes to metal centers, we synthesized organometallic coordination polymer nanocatalysts and silica gel-supported quinonoid rhodium catalysts, the latter using a surface sol-gel technique. The resulting heterogeneous catalysts showed activity in the stereospecific polymerization of phenylacetylene. PMID:23745596

  17. Microporosity Prediction and Validation for Ni-based Superalloy Castings

    NASA Astrophysics Data System (ADS)

    Guo, J.; Beckermann, C.; Carlson, K.; Hirvo, D.; Bell, K.; Moreland, T.; Gu, J.; Clews, J.; Scott, S.; Couturier, G.; Backman, D.

    2015-06-01

    Microporosityin high performance aerospace castings can reduce mechanical properties and consequently degrade both component life and durability. Therefore, casting engineers must be able to both predict and reduce casting microporosity. A dimensionless Niyama model has been developed [1] that predicts local microporosity by accounting for local thermal conditions during casting as well as the properties and solidification characteristics of the cast alloy. Unlike the well-known Niyama criterion, application of the dimensionless Niyama model avoids the need to find a threshold Niyama criterion below which shrinkage porosity forms - a criterion which can be determined only via extensive alloy dependent experimentation. In the present study, the dimensionless Niyama model is integrated with a commercial finite element casting simulation software, which can now more accurately predict the location-specific shrinkage porosity volume fraction during solidification of superalloy castings. These microporosity predictions are validated by comparing modelled results against radiographically and metallographically measured porosity for several Ni-based superalloy equiaxed castings that vary in alloy chemistry with a focus on plates of changing draft angle and thickness. The simulation results agree well with experimental measurements. The simulation results also show that the dimensionless Niyama model can not only identify the location but also the average volume fraction of microporosity distribution in these equiaxed investment cast Ni-based superalloy experiments of relatively simple geometry.

  18. Autothermal reforming of propane over Ni-based hydrotalcite catalysts.

    PubMed

    Park, Sun-Young; Kim, Jong-Ho; Moon, Dong-Ju; Park, Nam-Cook; Kim, Young-Chul

    2010-05-01

    Ni-based hydrotalcite catalysts were investigated for ATR of propane in a fixed-bed flow reactor. The reactions were carried out with a H2O/C/O2 stream ratio of 3/1/0.73 at temperatures ranging from 300 to 700 degrees C. The solvents used in the manufacture of Ni-based catalysts noble metal/Ni/MgAl catalysts or substituted active material were changed in order to decrease the level of catalyst deactivation. The use of a mixture of ethanol and water during the formation of the Pd-Ni/MgAl catalyst produced a higher hydrogen yield than that using water only. In addition, the use of acetone in the synthesis of Ru-Ni/MgAl catalyst produced a higher hydrogen yield than using water only. This shows that the solvents used for the noble metals affect the degree of dispersion and particle size of the nickel and prevented carbon deposition resulting in the enhanced hydrogen selectivity and catalyst activity. Active metals were substituted during the preparation of hydrotalcite catalysts. Among the catalysts prepared with various ratio (Ni:Fe) tested at high temperature, the ratio, Ni:Fe = 75:25, showed best performance. There was less sintering of Ni particles due to substitution of the active metal at the optimal ratio. PMID:20358916

  19. Transuranic organometallics: The next generation

    SciTech Connect

    Zwick, B.D.; Sattelberger, A.P.; Avens, L.R.

    1990-01-01

    Neptunium and plutonium metal react cleanly with 3/2 equiv. I{sub 2} in aprotic ligating solvents, L, such as tetrahydrofuran (THF), pyridine (Py), and dimethylsulfoxide (DMSO) to give the triiodide complexes as tetrasolvates, AnI{sub 3}(L){sub 4} (An = Np, L = THF (1)); An = Pu, L = THF (2a), Py (2b), and DMSO (2c). These triiodide complexes are convenient precursors to new transuranic compounds. Reaction of the triiodide complexes 1 and 2a hexane with 3 equiv. of sodium bis(trimethylsilyl)amide give the volatile, solvate-free tris(silylamide) complexes, An(N(SiMe{sub 3}){sub 2}){sub 3} (An = Np, 3; An = Pu, 4). The silylamide complexes 3 and 4 undergo rapid reaction in hexane upon stoichiometric addition of HO-2,6-(t-C{sub 4}H{sub 9}){sub 2}C{sub 6}H{sub 3} to give the aryl oxide complexes An(O-2,6-(t-C{sub 4}H{sub 9}){sub 2}C{sub 6}H{sub 3}){sub 3} (An = Np, 5; An = Pu, 6). Preliminary investigations suggest that the aryl oxide complexes 5 and 6 react with lithium bis(trimethylsilyl)methanide, Li{sup +} CH(SiMe{sub 3}){sub 2}, in hexane to give the homoleptic alkyl complexes An(CH(SiMe{sub 3}){sub 2}){sub 3} (An = Np, 7; An = Pu, 8). The homoleptic silylamide, aryl oxide, and alkyl complexes are the first to be reported for transuranic elements. 17 refs.

  20. Sample treatment in chromatography-based speciation of organometallic pollutants.

    PubMed

    Gómez-Riza, J L; Morales, E; Giráldez, I; Sánchez-Rodas, D; Velasco, A

    2001-12-14

    Speciation analysis is nowadays performed routinely in many laboratories to control the quality of the environment, food and health. Chemical speciation analyses generally include the study of different oxidation state of elements or individual organometallic compounds. The determination of the different chemical forms of elements is still an analytical challenge, since they are often unstable and concentrations in different matrices of interest are in the microg l(-1) or even in the ng l(-1) range (e.g., estuarine waters) or ng g(-1) in sediments and biological tissues. For this reason, sensitive and selective analytical atomic techniques are being used as available detectors for speciation, generally coupled with chromatography for the time-resolved introduction of analytes into the atomic spectrometer. The complexity of these instrumental couplings has a straightforward consequence on the duration of the analysis, but sample preparation to separate and transfer the chemical species present in the sample into a solution to be accepted readily by a chromatographic column is the more critical step of total analysis, and demands considerable operator skills and time cost. Traditionally, liquid-liquid extraction has been employed for sample treatment with serious disadvantages, such as consumption, disposal and long-term exposure to organic solvent. In addition, they are usually cumbersome and time-consuming. Therefore, the introduction of new reagents such as sodium tetraethylborate for the simultaneous derivatization of several elements has been proposed. Other possibilities are based in the implementation of techniques for efficient and accelerated isolation of species from the sample matrix. This is the case for microwave-assisted extraction, solid-phase extraction and microextraction, supercritical fluid extraction or pressurized liquid extraction, which offer new possibilities in species treatment, and the advantages of a drastic reduction of the extraction

  1. Bifilm Defects in Ni-Based Alloy Castings

    NASA Astrophysics Data System (ADS)

    Campbell, John; Tiryakioğlu, Murat

    2012-08-01

    The Ni-base superalloys, which are normally melted and cast in a vacuum, entrain their surface-oxide film during turbulent pouring of the melt; unfortunately at this time, this process is universally practiced for investment castings of these materials. The entrained film becomes a bifilm crack automatically, so that cast alloys have a large population of cracks that controls their failure behavior. The problems of the growth of single crystals and the welding of polycrystalline alloys are reviewed to illustrate the central role of bifilms in the cracking of turbine blades, the heat-affected zones of welds, and the reliability of properties. It has been demonstrated that improved gravity pouring systems can reduce these problems significantly, but only countergravity filling of molds is expected to result in defect-free castings. Recent cases in which turbine blades failed in service are examined, and the central role of bifilm defects in these failures is discussed.

  2. Microwave properties of Ni-based ferromagnetic inverse opals

    NASA Astrophysics Data System (ADS)

    Kostylev, M.; Stashkevich, A. A.; Roussigné, Y.; Grigoryeva, N. A.; Mistonov, A. A.; Menzel, D.; Sapoletova, N. A.; Napolskii, K. S.; Eliseev, A. A.; Lukashin, A. V.; Grigoriev, S. V.; Samarin, S. N.

    2012-11-01

    Investigations of microwave properties of Ni-based inverse ferromagnetic opal-like film with the [111] axis of the fcc structure along the normal direction to the film have been carried out in the 2-18 GHz frequency band. We observed multiple spin wave resonances for the magnetic field applied perpendicular to the film, i.e., along the [111] axis of this artificial crystal. For the field applied in the film plane, a broad band of microwave absorption is observed, which does not contain a fine structure. The field ranges of the responses observed are quite different for these two magnetization directions. This suggests a collective magnetic ground state or shape anisotropy and collective microwave dynamics for this foam-like material. This result is in agreement with SQUID measurements of hysteresis loops for the material. Two different models for this collective behavior are suggested that satisfactorily explain the major experimental results.

  3. Organometallic Antitumor Compounds: Ferrocifens as Precursors to Quinone Methides.

    PubMed

    Wang, Yong; Pigeon, Pascal; Top, Siden; McGlinchey, Michael J; Jaouen, Gérard

    2015-08-24

    The synthesis and chemical oxidation profile of a new generation of ferrocifen derivatives with strong antiproliferative behavior in vitro is reported. In particular, the hydroxypropyl derivative HO(CH2 )3 C(Fc)=C(C6 H4 OH)2 (3 b) exhibited exceptional antiproliferative activity against the cancer cell lines HepG2 and MDA-MB-231 TNBC, with IC50 values of 0.07 and 0.11 μM, respectively. Chemical oxidation of 3 b yielded an unprecedented tetrahydrofuran-substituted quinone methide (QM) via internal cyclization of the hydroxyalkyl chain, whereas the corresponding alkyl analogue CH3 CH2 -C(Fc)=C(C6 H4 OH)2 merely formed a vinyl QM. The ferrocenyl group in 3 b plays a key role, not only as an intramolecular reversible redox "antenna", but also as a stabilized carbenium ion "modulator". The presence of the oxygen heterocycle in 3 b-QM enhances its stability and leads to a unique chemical oxidation profile, thus revealing crucial clues for deciphering its mechanism of action in vivo. PMID:26179051

  4. Organometallic Ru(II) Photosensitizers Derived from π-Expansive Cyclometalating Ligands: Surprising Theranostic PDT Effects.

    PubMed

    Sainuddin, Tariq; McCain, Julia; Pinto, Mitch; Yin, Huimin; Gibson, Jordan; Hetu, Marc; McFarland, Sherri A

    2016-01-01

    The purpose of the present study was to investigate the influence of π-expansive cyclometalating ligands on the photophysical and photobiological properties of organometallic Ru(II) compounds. Four compounds with increasing π conjugation on the cyclometalating ligand were prepared, and their structures were confirmed by HPLC, 1D and 2D (1)H NMR, and mass spectrometry. The properties of these compounds differed substantially from their Ru(II) polypyridyl counterparts. Namely, they were characterized by red-shifted absorption, very weak to no room temperature phosphorescence, extremely short phosphorescence state lifetimes (<10 ns), low singlet oxygen quantum yields (0.5-8%), and efficient ligand-centered fluorescence. Three of the metal complexes were very cytotoxic to cancer cells in the dark (EC50 values = 1-2 μM), in agreement with what has traditionally been observed for Ru(II) compounds derived from small C^N ligands. Surprisingly, the complex derived from the most π-expansive cyclometalating ligand exhibited no cytotoxicity in the dark (EC50 > 300 μM) but was phototoxic to cells in the nanomolar regime. Exceptionally large phototherapeutic margins, exceeding 3 orders of magnitude in some cases, were accompanied by bright ligand-centered intracellular fluorescence in cancer cells. Thus, Ru(II) organometallic systems derived from π-expansive cyclometalating ligands, such 4,9,16-triazadibenzo[a,c]napthacene (pbpn), represent the first class of potent light-responsive Ru(II) cyclometalating agents with theranostic potential. PMID:26672769

  5. (Mechanistic examination of organometallic electron transfer reactions: Annual report, 1989)

    SciTech Connect

    Not Available

    1989-01-01

    Our mechanistic examination of electron transfer reactions between organometallic complexes has required data from our stopped-flow infrared spectrophotometer that was constructed in the first year. Our research on organometallic electron transfer reaction mechanisms was recognized by an invitation to the Symposium on Organometallic Reaction Mechanisms at the National ACS meeting in Miami. We have obtained a reasonable understanding of the electron transfer reactions between metal cations and anions and between metal carbonyl anions and metal carbonyl dimers. In addition we have begun to obtain data on the outer sphere electron transfer between metal carbonyl anions and coordination complexes and on reactions involving cluster anions.

  6. [Mechanistic examination of organometallic electron transfer reactions: Annual report, 1989

    SciTech Connect

    Not Available

    1989-12-31

    Our mechanistic examination of electron transfer reactions between organometallic complexes has required data from our stopped-flow infrared spectrophotometer that was constructed in the first year. Our research on organometallic electron transfer reaction mechanisms was recognized by an invitation to the Symposium on Organometallic Reaction Mechanisms at the National ACS meeting in Miami. We have obtained a reasonable understanding of the electron transfer reactions between metal cations and anions and between metal carbonyl anions and metal carbonyl dimers. In addition we have begun to obtain data on the outer sphere electron transfer between metal carbonyl anions and coordination complexes and on reactions involving cluster anions.

  7. Determining the Quantum Efficiency for Activation of an Organometallic Photoinitiator for Cationic Polymerization: An Experiment for the Physical or Inorganic Chemistry Laboratory

    ERIC Educational Resources Information Center

    Hayes, David M.; Mahar, Maura; Schnabel, R. Chris; Shah, Paras; Lees, Alistair J.; Jakubek, Vladimir

    2007-01-01

    We present a new laboratory experiment on the photochemistry of organometallic [eta][superscript 5],[eta][superscript 6]-mixed-sandwich compounds, which is suitable for both the physical chemistry and inorganic chemistry laboratory. Specifically, students use 1,10-phenanthroline to trap the intermediate formed when…

  8. Organometallic electrochemistry based on electrolytes containing weakly-coordinating fluoroarylborate anions.

    PubMed

    Geiger, William E; Barrière, Frédéric

    2010-07-20

    -deficient organometallic compounds are subject to nucleophilic attack by the traditional family of electrolyte anions. With a view to testing the scope of the much less nucleophililic WCAs in providing a benign electrolyte anion for the generation of organometallic cation radicals, we carried out a series of studies on transition metal sandwich and half-sandwich compounds. The model compounds were chosen both for their fundamental importance and because their radical cations had been neither isolated nor spectrally characterized, despite many previous electrochemical investigations with traditional anions. The oxidation of prototypical organometallic compounds, such as the sandwich-structured ruthenocene and the piano-stool structured Cr(eta(6)-C(6)H(6))(CO)(3), Mn(eta(5)-C(5)H(5))(CO)(3), Re(eta(5)-C(5)H(5))(CO)(3), and Co(eta(5)-C(5)H(5))(CO)(2), gave the first definitive in situ characterization of their radical cations. In several cases, the kinetic stabilization of the anodic products allowed the identification of dimers or unique dimer radicals having weak metal-metal bonds and provided new preparative options for organometallic systems. In terms of thermodynamic effects, the lower ion-pairing abilities of WCAs and their good solubility in a broad range of solvents, including those of lower polarity, permitted a systematic study that yielded an integrated model of how to use solvent-electrolyte combinations to manipulate the E(1/2) differences of compounds undergoing multiple electron-transfer reactions. Although the efficacy of WCA-based electrolytes in organometallic anodic chemistry is now established, WCAs might further expand applications of organic redox chemistry. Other WCAs, including those derived from carboranes and fluorinated alkoxyaluminates, merit additional studies. PMID:20345126

  9. Use of column V alkyls in organometallic vapor phase epitaxy (OMVPE)

    NASA Technical Reports Server (NTRS)

    Ludowise, M. J.; Cooper, C. B., III

    1982-01-01

    The use of the column V-trialkyls trimethylarsenic (TMAs) and trimethylantimony (TMSb) for the organometallic vapor phase epitaxy (OM-VPE) of III-V compound semiconductors is reviewed. A general discussion of the interaction chemistry of common Group III and Group V reactants is presented. The practical application of TMSb and TMAs for OM-VPE is demonstrated using the growth of GaSb, GaAs(1-y)Sb(y), Al(x)Ga(1-x)Sb, and Ga(1-x)In(x)As as examples.

  10. High-sensitivity molecular organometallic resist for EUV (MORE)

    NASA Astrophysics Data System (ADS)

    Passarelli, James; Murphy, Michael; Del Re, Ryan; Sortland, Miriam; Dousharm, Levi; Vockenhuber, Michaela; Ekinci, Yasin; Neisser, Mark; Freedman, Daniel A.; Brainard, Robert L.

    2015-03-01

    We have developed organometallic carboxylate compounds [RnM(O2CR')2] capable of acting as negativetone EUV resists. Overall, the best and fastest resists contain antimony, are pentavalent and the carboxylate group contains a polymerizable olefin (e.g. acrylate, methacrylate or styrenecarboxylate). Evidence suggests that high sensitivity is achieved through the polymerization of olefins in the exposed region. We have performed a systematic sensitivity study of molecules of the type RnM(O2CR')2 where we have studied seven R groups, four main group metals (M), and three polymerizable carboxylate groups (O2CR'). We found that the greatest predictor of sensitivity of the RnSb(O2CR')2 resists is their level of polymerizable olefins. We mathematically define the polymerizable olefin loading (POL) as the ratio of the number of olefins vs. the number of non-hydrogen atoms. Linear and log plots of Emax vs. POL for a variety of molecules of the type R3Sb(O2CR')2 lend insight into the behaviour of these resists.

  11. Development of Organometallic S6K1 Inhibitors

    PubMed Central

    2015-01-01

    Aberrant activation of S6 kinase 1 (S6K1) is found in many diseases, including diabetes, aging, and cancer. We developed ATP competitive organometallic kinase inhibitors, EM5 and FL772, which are inspired by the structure of the pan-kinase inhibitor staurosporine, to specifically inhibit S6K1 using a strategy previously used to target other kinases. Biochemical data demonstrate that EM5 and FL772 inhibit the kinase with IC50 value in the low nanomolar range at 100 μM ATP and that the more potent FL772 compound has a greater than 100-fold specificity over S6K2. The crystal structures of S6K1 bound to staurosporine, EM5, and FL772 reveal that the EM5 and FL772 inhibitors bind in the ATP binding pocket and make S6K1-specific contacts, resulting in changes to the p-loop, αC helix, and αD helix when compared to the staurosporine-bound structure. Cellular data reveal that FL772 is able to inhibit S6K phosphorylation in yeast cells. Together, these studies demonstrate that potent, selective, and cell permeable S6K1 inhibitors can be prepared and provide a scaffold for future development of S6K inhibitors with possible therapeutic applications. PMID:25356520

  12. Organometallic carboxylate resists for extreme ultraviolet with high sensitivity

    NASA Astrophysics Data System (ADS)

    Passarelli, James; Murphy, Michael; Re, Ryan Del; Sortland, Miriam; Hotalen, Jodi; Dousharm, Levi; Fallica, Roberto; Ekinci, Yasin; Neisser, Mark; Freedman, Daniel A.; Brainard, Robert L.

    2015-10-01

    We have developed organometallic carboxylate compounds [RnM)] capable of acting as negative-tone extreme ultraviolet (EUV) resists. The most sensitive of these resists contain antimony, three R-groups and two carboxylate groups, and carboxylate groups with polymerizable olefins (e.g., acrylate, methacrylate, or styrenecarboxylate). Evidence suggests that high sensitivity is achieved through the polymerization of olefins in the exposed region. We have performed a systematic sensitivity study of the molecules of the type RnM) where we have studied seven R groups, four main group metals (M), and three polymerizable carboxylate groups (O2CR‧). The sensitivity of these resists was evaluated using Emax or dose to maximum resist thickness after exposure and development. We found that the greatest predictor of sensitivity of the RnSb) resists is their level of polymerizable olefins. We mathematically define the polymerizable olefin loading (POL) as the ratio of the number of olefins versus the number of nonhydrogen atoms. Linear and log plots of Emax versus POL for a variety of molecules of the type R3Sb) lend insight into the behavior of these resists.

  13. Non-metallocene organometallic complexes and related methods and systems

    DOEpatents

    Agapie, Theodor; Golisz, Suzanne Rose; Tofan, Daniel; Bercaw, John E.

    2010-12-07

    A non-metallocene organometallic complex comprising a tridentate ligand and a metal bonded to a tridentate ligand, wherein two substituted aryl groups in the tridentate ligand are connected to a cyclic group at the ortho position via semi-rigid ring-ring linkages, and selected so to provide the resulting non-metallocene organometallic complex with a C.sub.S geometry, a C.sub.1 geometry, a C.sub.2 geometry or a C.sub.2v geometry. Method for performing olefin polymerization with a non-metallocene organometallic complex as a catalyst, related catalytic systems, tridentate ligand and method for providing a non-metallocene organometallic complex.

  14. Some Tendencies in the Literature of Organometallic Chemistry

    ERIC Educational Resources Information Center

    Haiduc, Ionel

    1972-01-01

    A survey of the number of references published annually for individual elements or groups of elements suggests that the organometallic chemistry literature is approaching a phase of slower increase. (Author/NH)

  15. Supported organometallic complexes: Surface chemistry, spectroscopy, and catalysis

    SciTech Connect

    Marks, T.J.

    1990-02-01

    The goal of our program is to define those modes of interaction that take place between organometallic molecules and inorganic surfaces and, ultimately, to correlate various molecule-surface structures with catalytic properties.

  16. Advanced polymer chemistry of organometallic anions

    SciTech Connect

    Chamberlin, R.M.; Abney, K.D.; Balaich, G.J.; Fino, S.A.

    1997-11-01

    This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The objective of the project was to prepare and characterize new polymers incorporating cobalt dicarbollide. Specific goals were to prepare polymerizable cobalt dicarbollide monomers using the nucleophilic substitution route discovered in laboratories and to establish the reaction conditions required to form polymers from these complexes. This one-year project resulted in two publications (in press), and provided the foundation for further investigations into polymer synthesis and characterization using cobalt dicarbollide and other metallocarboranes. Interest in synthesizing organometallic polymers containing the cobalt bis(dicarbollide) anion is motivated by their possible application as cation exchange materials for the remediation of cesium-137 and strontium-90 from nuclear wastes.

  17. Ni-based nanoalloys: Towards thermally stable highly magnetic materials

    NASA Astrophysics Data System (ADS)

    Palagin, Dennis; Doye, Jonathan P. K.

    2014-12-01

    Molecular dynamics simulations and density functional theory calculations have been used to demonstrate the possibility of preserving high spin states of the magnetic cores within Ni-based core-shell bimetallic nanoalloys over a wide range of temperatures. We show that, unlike the case of Ni-Al clusters, Ni-Ag clusters preserve high spin states (up to 8 μB in case of Ni13Ag32 cluster) due to small hybridization between the electronic levels of two species. Intriguingly, such clusters are also able to maintain geometrical and electronic integrity of their cores at temperatures up to 1000 K (e.g., for Ni7Ag27 cluster). Furthermore, we also show the possibility of creating ordered arrays of such magnetic clusters on a suitable support by soft-landing pre-formed clusters on the surface, without introducing much disturbance in geometrical and electronic structure of the cluster. We illustrate this approach with the example of Ni13Ag38 clusters adsorbed on the Si(111)-(7×7) surface, which, having two distinctive halves to the unit cell, acts as a selective template for cluster deposition.

  18. Ni-based nanoalloys: Towards thermally stable highly magnetic materials

    SciTech Connect

    Palagin, Dennis Doye, Jonathan P. K.

    2014-12-07

    Molecular dynamics simulations and density functional theory calculations have been used to demonstrate the possibility of preserving high spin states of the magnetic cores within Ni-based core-shell bimetallic nanoalloys over a wide range of temperatures. We show that, unlike the case of Ni–Al clusters, Ni–Ag clusters preserve high spin states (up to 8 μ{sub B} in case of Ni{sub 13}Ag{sub 32} cluster) due to small hybridization between the electronic levels of two species. Intriguingly, such clusters are also able to maintain geometrical and electronic integrity of their cores at temperatures up to 1000 K (e.g., for Ni{sub 7}Ag{sub 27} cluster). Furthermore, we also show the possibility of creating ordered arrays of such magnetic clusters on a suitable support by soft-landing pre-formed clusters on the surface, without introducing much disturbance in geometrical and electronic structure of the cluster. We illustrate this approach with the example of Ni{sub 13}Ag{sub 38} clusters adsorbed on the Si(111)–(7×7) surface, which, having two distinctive halves to the unit cell, acts as a selective template for cluster deposition.

  19. Slip Analysis in a Ni-base Superalloy

    NASA Technical Reports Server (NTRS)

    Westbrooke, Eboni F.; Forero, Luis E.; Ebrahimi, Fereshteh

    2004-01-01

    A Ni-base superalloy single crystal with Gamma/Gamma' structure was tested at room temperature along the , <110> and <111> directions. Consistent with previously reported investigations, this alloy did not obey the Schmid law and the CRSS (critical resolved shear stress) was noticeably lower for the <111>-oriented samples. Furthermore, the strain hardening rate decreased and the degree of deformation localization increased in the order of <111>, and <110> orientations. The appearance and orientation of deformation traces were found to depend on the loading orientation as well as the amount of strain. In general, when Gamma'-particles were sheared, the traces followed the expected octahedral shear planes. It is demonstrated that the wavy deformation traces that do not follow the {111} planes are associated with changes in the gamma-channels width and the falling off of the gamma-particles. In this paper the evolution of deformation bands are discussed in terms of plastic localization at microscopic, mesoscopic and macroscopic levels.

  20. Local structure of Iridium organometallic catalysts covalently bonded to carbon nanotubes.

    NASA Astrophysics Data System (ADS)

    Blasco, J.; Cuartero, V.; Subías, G.; Jiménez, M. V.; Pérez-Torrente, J. J.; Oro, L. A.; Blanco, M.; Álvarez, P.; Blanco, C.; Menéndez, R.

    2016-05-01

    Hybrid catalysts based on Iridium N-heterocyclic carbenes anchored to carbon nanotubes (CNT) have been studied by XAFS spectroscopy. Oxidation of CNT yields a large amount of functional groups, mainly hydroxyl groups at the walls and carboxylic groups at the tips, defects and edges. Different kinds of esterification reactions were performed to functionalize oxidized CNT with imidazolium salts. Then, the resulting products were reacted with an Ir organometallic compound to form hybrid catalysts efficient in hydrogen transfer processes. XANES spectroscopy agree with the presence of Ir(I) in these catalysts and the EXAFS spectra detected differences in the local structure of Ir atoms between the initial Ir organometallic compound and the Ir complexes anchored to the CNT. Our results confirm that the halide atom, present in the Ir precursor, was replaced by oxygen from -OH groups at the CNT wall in the first coordination shell of Ir. The lability of this group accounts for the good recyclability and the good efficiency shown by these hybrid catalysts.

  1. Half-metallicity in 2D organometallic honeycomb frameworks.

    PubMed

    Sun, Hao; Li, Bin; Zhao, Jin

    2016-10-26

    Half-metallic materials with a high Curie temperature (T C) have many potential applications in spintronics. Magnetic metal free two-dimensional (2D) half-metallic materials with a honeycomb structure contain graphene-like Dirac bands with π orbitals and show excellent aspects in transport properties. In this article, by investigating a series of 2D organometallic frameworks with a honeycomb structure using first principles calculations, we study the origin of forming half-metallicity in this kind of 2D organometallic framework. Our analysis shows that charge transfer and covalent bonding are two crucial factors in the formation of half-metallicity in organometallic frameworks. (i) Sufficient charge transfer from metal atoms to the molecules is essential to form the magnetic centers. (ii) These magnetic centers need to be connected through covalent bonding, which guarantee the strong ferromagnetic (FM) coupling. As examples, the organometallic frameworks composed by (1,3,5)-benzenetricarbonitrile (TCB) molecules with noble metals (Au, Ag, Cu) show half-metallic properties with T C as high as 325 K. In these organometallic frameworks, the strong electronegative cyano-groups (CN groups) drive the charge transfer from metal atoms to the TCB molecules, forming the local magnetic centers. These magnetic centers experience strong FM coupling through the d-p covalent bonding. We propose that most of the 2D organometallic frameworks composed by molecule-CN-noble metal honeycomb structures contain similar half metallicity. This is verified by replacing TCB molecules with other organic molecules. Although the TCB-noble metal organometallic framework has not yet been synthesized, we believe the development of synthesizing techniques and facility will enable the realization of them. Our study provides new insight into the 2D half-metallic material design for the potential applications in nanotechnology. PMID:27541575

  2. Sulfur-bonded thiophenes in organometallic rhenium complexes and adsorption of isocyanides on gold

    SciTech Connect

    Robertson, M.J.

    1993-08-01

    This dissertation contains results of research conducted in two different areas: (1) organometallic synthesis and reactivity, and (2) organometallic surface chemistry. In the synthesis and reactivity studies, sulfur coordination of thiophene and benzo[b]thiophene to the metal center in organometallic rhenium complexes is examined. In the surface chemistry studies, diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) is used to analyze the adsorption of several isocyanides on the surface of gold powder. Results are compared and contrasted to known organometallic chemistry.

  3. Ultrafast studies of organometallic photochemistry: The mechanism of carbon-hydrogen bond activation in solution

    SciTech Connect

    Bromberg, S.E.

    1998-05-01

    When certain organometallic compounds are photoexcited in room temperature alkane solution, they are able to break or activate the C-H bonds of the solvent. Understanding this potentially practical reaction requires a detailed knowledge of the entire reaction mechanism. Because of the dynamic nature of chemical reactions, time-resolved spectroscopy is commonly employed to follow the important events that take place as reactants are converted to products. For the organometallic reactions examined here, the electronic/structural characteristics of the chemical systems along with the time scales for the key steps in the reaction make ultrafast UV/Vis and IR spectroscopy along with nanosecond Step-Scan FTIR spectroscopy the ideal techniques to use for this study. An initial study of the photophysics of (non-activating) model metal carbonyls centering on the photodissociation of M(CO){sub 6} (M = Cr, W, Mo) was carried out in alkane solutions using ultrafast IR spectroscopy. Next, picosecond UV/vis studies of the C-H bond activation reaction of Cp{sup *}M(CO){sub 2} (M = Rh, Ir), conducted in room temperature alkane solution, are described in an effort to investigate the origin of the low quantum yield for bond cleavage ({approximately}1%). To monitor the chemistry that takes place in the reaction after CO is lost, a system with higher quantum yield is required. The reaction of Tp{sup *}Rh(CO){sub 2} (Tp{sup *} = HB-Pz{sub 3}{sup *}, Pz{sup *} = 3,5-dimethylpyrazolyl) in alkanes has a quantum yield of {approximately}30%, making time resolved spectroscopic measurements possible. From ultrafast IR experiments, two subsequently formed intermediates were observed. The nature of these intermediates are discussed and the first comprehensive reaction mechanism for a photochemical C-H activating organometallic complex is presented.

  4. Atom-Precise Organometallic Zinc Clusters.

    PubMed

    Banh, Hung; Dilchert, Katharina; Schulz, Christine; Gemel, Christian; Seidel, Rüdiger W; Gautier, Régis; Kahlal, Samia; Saillard, Jean-Yves; Fischer, Roland A

    2016-03-01

    The bottom-up synthesis of organometallic zinc clusters is described. The cation {[Zn10 ](Cp*)6 Me}(+) (1) is obtained by reacting [Zn2 Cp*2 ] with [FeCp2 ][BAr4 (F) ] in the presence of ZnMe2 . In the presence of suitable ligands, the high reactivity of 1 enables the controlled abstraction of single Zn units, providing access to the lower-nuclearity clusters {[Zn9 ](Cp*)6 } (2) and {[Zn8 ](Cp*)5 ((t) BuNC)3 }(+) (3). According to DFT calculations, 1 and 2 can be described as closed-shell species that are electron-deficient in terms of the Wade-Mingos rules because the apical ZnCp* units that constitute the cluster cage do not have three, but only one, frontier orbitals available for cluster bonding. Zinc behaves flexibly in building the skeletal metal-metal bonds, sometimes providing one major frontier orbital (like Group 11 metals) and sometimes providing three frontier orbitals (like Group 13 elements). PMID:26846901

  5. Combinatorial screening of inorganic and organometallic materials

    DOEpatents

    Schultz, Peter G.; Xiang, Xiaodong; Goldwasser, Isy

    2002-01-01

    Methods and apparatus for the preparation and use of a substrate having an array of diverse materials in predefined regions thereon. A substrate having an array of diverse materials thereon is generally prepared by delivering components of materials to predefined regions on a substrate, and simultaneously reacting the components to form at least two materials. Materials which can be prepared using the methods and apparatus of the present invention include, for example, covalent network solids, ionic solids and molecular solids. More particularly, materials which can be prepared using the methods and apparatus of the present invention include, for example, inorganic materials, intermetallic materials, metal alloys, ceramic materials, organic materials, organometallic materials, non-biological organic polymers, composite materials (e.g., inorganic composites, organic composites, or combinations thereof), etc. Once prepared, these materials can be screened for useful properties including, for example, electrical, thermal, mechanical, morphological, optical, magnetic, chemical, or other properties. Thus, the present invention provides methods for the parallel synthesis and analysis of novel materials having useful properties.

  6. Tuning exchange interactions in organometallic semiconductors

    NASA Astrophysics Data System (ADS)

    Rawat, Naveen; Manning, Lane W.; Hua, Kim-Ngan; Headrick, Randall L.; Cherian, Judy G.; Bishop, Michael M.; McGill, Stephen A.; Furis, Madalina I.

    2015-09-01

    Organic semiconductors are emerging as a leading area of research as they are expected to overcome limitations of inorganic semiconductor devices for certain applications where low cost manufacturing, device transparency in the visible range or mechanical flexibility are more important than fast switching times. Solution processing methods produce thin films with millimeter sized crystalline grains at very low cost manufacturing prices, ideally suited for optical spectroscopy investigations of long range many-body effects in organic systems. To this end, we synthesized an entire family of organosoluble 3-d transition metal Pc's and successfully employed a novel solution-based pen-writing deposition technique to fabricate long range ordered thin films of mixtures of metal-free (H2Pc) molecule and organometallic phthalocyanines (MPc's). Our previous studies on the parent MPc crystalline thin films identified different electronic states mediating exchange interactions in these materials. This understanding of spin-dependent exchange interaction between delocalized π-electrons with unpaired d spins enabled the further tuning of these interactions by mixing CoPc and H2Pc in different ratios ranging from 1:1 to 1000:1 H2Pc:MPc. The magnitude of the exchange is also tunable as a function of the average distance between unpaired spins in these materials. Furthermore, high magnetic field (B < 25T) MCD and magneto-photoluminescence show evidence of spin-polarized band-edge excitons in the same materials.

  7. Organic or organometallic template mediated clay synthesis

    SciTech Connect

    Gregar, K.C.; Winans, R.E.; Botto, R.E.

    1992-12-31

    A method is given for incorporating diverse varieties of intercalants or templates directly during hydrothermal synthesis of clays such as hectorite or montmorillonite-type layer-silicate clays. For a hectorite layer-silicate clay, refluxing a gel of silica sol, magnesium hydroxide sol and LiF for 2 days with an organic or organometallic intercalant or template results in crystalline products containing either (a) organic dye molecules such as ethyl violet and methyl green, (b) dye molecules such as alcian blue based on a Cu(II)-phthalocyannine complex, or (c) transition metal complexes such as Ru(II)phenanthroline and Co(III)sepulchrate or (d) water-soluble porphyrins and metalloporphyrins. Montmorillonite-type clays are made by the method taught by US patent No. 3,887,454 issued to Hickson, June 13, 1975; however, a variety of intercalants or templates may be introduced. The intercalants or templates should have water-solubility, positive charge, and thermal stability under moderately basic (pH 9-10) aqueous reflux conditions or hydrothermal pressurized conditions for the montmorillonite-type clays.

  8. Organic or organometallic template mediated clay synthesis

    DOEpatents

    Gregar, K.C.; Winans, R.E.; Botto, R.E.

    1994-05-03

    A method is described for incorporating diverse varieties of intercalates or templates directly during hydrothermal synthesis of clays such as hectorite or montmorillonite-type layer-silicate clays. For a hectorite layer-silicate clay, refluxing a gel of silica sol, magnesium hydroxide sol and lithium fluoride for two days in the presence of an organic or organometallic intercalate or template results in crystalline products containing either (a) organic dye molecules such as ethyl violet and methyl green, (b) dye molecules such as alcian blue that are based on a Cu(II)-phthalocyannine complex, or (c) transition metal complexes such as Ru(II)phenanthroline and Co(III)sepulchrate or (d) water-soluble porphyrins and metalloporphyrins. Montmorillonite-type clays are made by the method taught by U.S. Pat. No. 3,887,454 issued to Hickson, Jun. 13, 1975; however, a variety of intercalates or templates may be introduced. The intercalates or templates should have (i) water-solubility, (ii) positive charge, and (iii) thermal stability under moderately basic (pH 9-10) aqueous reflux conditions or hydrothermal pressurized conditions for the montmorillonite-type clays. 22 figures.

  9. Organic or organometallic template mediated clay synthesis

    DOEpatents

    Gregar, Kathleen C.; Winans, Randall E.; Botto, Robert E.

    1994-01-01

    A method for incorporating diverse Varieties of intercalants or templates directly during hydrothermal synthesis of clays such as hectorite or montmorillonite-type layer-silicate clays. For a hectorite layer-silicate clay, refluxing a gel of silica sol, magnesium hydroxide sol and lithium fluoride for two days in the presence of an organic or organometallic intercalant or template results in crystalline products containing either (a) organic dye molecules such as ethyl violet and methyl green, (b) dye molecules such as alcian blue that are based on a Cu(II)-phthalocyannine complex, or (c) transition metal complexes such as Ru(II)phenanthroline and Co(III)sepulchrate or (d) water-soluble porphyrins and metalloporphyrins. Montmorillonite-type clays are made by the method taught by U.S. Pat. No. 3,887,454 issued to Hickson, Jun. 13, 1975; however, a variety of intercalants or templates may be introduced. The intercalants or templates should have (i) water-solubility, (ii) positive charge, and (iii) thermal stability under moderately basic (pH 9-10) aqueous reflux conditions or hydrothermal pressurized conditions for the montmorillonite-type clays.

  10. Modules for Introducing Organometallic Reactions: A Bridge between Organic and Inorganic Chemistry

    ERIC Educational Resources Information Center

    Schaller, Chris P.; Graham, Kate J.; Johnson, Brian J.

    2015-01-01

    Transition metal organometallic reactions have become increasingly important in the synthesis of organic molecules. A new approach has been developed to introduce organometallic chemistry, along with organic and inorganic chemistry, at the foundational level. This change highlights applications of organometallic chemistry that have dramatically…

  11. Estimate of conjugate gamma and gamma prime compositions in Ni-base superalloys

    NASA Technical Reports Server (NTRS)

    Dreshfield, R. L.

    1977-01-01

    Approaches for estimating the composition of the matrix phase of alloys from the melt composition are reviewed. The first method is based on assigning essentially fixed stoichiometry to precipitating phases and is typified by PHACOMP. The second method uses analytical geometry to interpret phase diagrams and is applicable to a two-phase region of a six-component Ni-base system. The geometric method is also applicable to commercial Ni-base superalloys.

  12. Mass Spectrometry Uncovers Molecular Reactivities of Coordination and Organometallic Gold(III) Drug Candidates in Competitive Experiments That Correlate with Their Biological Effects.

    PubMed

    Meier, Samuel M; Gerner, Christopher; Keppler, Bernhard K; Cinellu, Maria Agostina; Casini, Angela

    2016-05-01

    The reactivity of three cytotoxic organometallic gold(III) complexes with cyclometalated C,N,N and C,N ligands (either six- or five-membered metallacycles), as well as that of two representative gold(III) complexes with N-donor ligands, with biological nucleophiles has been studied by ESI-MS on ion trap and time-of-flight instruments. Specifically, the gold compounds were reacted with mixtures of nucleophiles containing l-histidine (imine), l-methionine (thioether), l-cysteine (thiol), l-glutamic acid (carboxylic acid), methylseleno-l-cysteine (selenoether), and in situ generated seleno-l-cysteine (selenol) to judge the preference of the gold compounds for binding to selenium-containing amino acid residues. Moreover, the gold compounds' reactivity was studied with proteins and nucleic acid building blocks. These experiments revealed profound differences between the coordination and organometallic families and even within the family of organometallics, which allowed insights to be gained into the compounds mechanisms of action. In particular, interactions with seleno-l-cysteine appear to reflect well the compounds' inhibition properties of the seleno-enzyme thioredoxin reductase and to a certain extent their antiproliferative effects in vitro. Therefore, mass spectrometry is successfully applied for linking the molecular reactivity and target preferences of metal-based drug candidates to their biological effects. Finally, this experimental setup is applicable to any other metallodrug that undergoes ligand substitution reactions and/or redox changes as part of its mechanism of action. PMID:26866307

  13. ROMP Synthesis of Iron-Containing Organometallic Polymers.

    PubMed

    Dragutan, Ileana; Dragutan, Valerian; Filip, Petru; Simionescu, Bogdan C; Demonceau, Albert

    2016-01-01

    The paper overviews iron-containing polymers prepared by controlled "living" ring-opening metathesis polymerization (ROMP). Developments in the design and synthesis of this class of organometallic polymers are highlighted, pinpointing methodologies and newest trends in advanced applications of hybrid materials based on polymers functionalized with iron motifs. PMID:26861276

  14. Organometalic carbosilane polymers containing vanadium and their preparation

    NASA Technical Reports Server (NTRS)

    Yajima, S.; Okamura, K.; Shishido, T.; Fukuda, K.

    1983-01-01

    The present invention concerns a new organometallic polymer material containing in part a vanadium-siloxane linkage (V-0-Si), which has excellent resistance to heat and oxidation and a high residue ratio after high temperature treatment in a non-oxidizing atmosphere, for example, nitrogen, argon, helium, ammonia, or hydrogen.

  15. Ligand Rearrangements of Organometallic Complexes inSolution

    SciTech Connect

    Shanoski, Jennifer E.

    2006-05-08

    Many chemical reactions utilize organometallic complexes as catalysts. These complexes find use in reactions as varied as bond activation, polymerization, and isomerization. This thesis outlines the construction of a new ultrafast laser system with an emphasis on the generation of tunable mid-infrared pulses, data collection, and data analysis.

  16. In –Situ Spectroscopic Investigation of Immobilized Organometallic Catalysts

    SciTech Connect

    Davis, Robert, J.

    2007-11-14

    Immobilized organometallic catalysts, in principle, can give high rates and selectivities like homogeneous catalysts with the ease of separation enjoyed by heterogeneous catalysts. However, the science of immobilized organometallics has not been developed because the field lies at the interface between the homogeneous and heterogeneous catalysis communities. By assembling an interdisciplinary research team that can probe all aspects of immobilized organometallic catalyst design, the entire reacting system can be considered, where the transition metal complex, the complex-support interface and the properties of the support can all be considered simultaneously from both experimental and theoretical points of view. Researchers at Georgia Tech and the University of Virginia are studying the fundamental principles that can be used to understand and design future classes of immobilized organometallic catalysts. In the framework of the overall collaborative project with Georgia Tech, our work focused on (a) the X-ray absorption spectroscopy of an immobilized Pd-SCS-O complex (b) the mode of metal leaching from supported Pd catalysts during Heck catalysis and (c) the mode of deactivation of Jacobsen’s Co-salen catalysts during the hydrolytic kinetic resolution of terminal epoxides. Catalysts containing supported Pd pincer complexes, functionalized supports containing mercapto and amine groups, and oligomeric Co-salen catalysts were synthesized at Georgia Tech and sent to the University of Virginia. Incorporation of Pd onto several different kinds of supports (silica, mercapto-functionalized silica, zeolite Y) was performed at the University of Virginia.

  17. Rational design of an organometallic glutathione transferase inhibitor

    SciTech Connect

    Ang, W.H.; Parker, L.J.; De Luca, A.; Juillerat-Jeanneret, L.; Morton, C.J.; LoBello, M.; Parker, M.W.; Dyson, P.J.

    2010-08-17

    A hybrid organic-inorganic (organometallic) inhibitor was designed to target glutathione transferases. The metal center is used to direct protein binding, while the organic moiety acts as the active-site inhibitor. The mechanism of inhibition was studied using a range of biophysical and biochemical methods.

  18. A "Classic Papers" Approach to Teaching Undergraduate Organometallic Chemistry

    ERIC Educational Resources Information Center

    Duncan, Andrew P.; Johnson, Adam R.

    2007-01-01

    We have structured an upper-level undergraduate course in organometallic chemistry on a selection of "classic" publications in the field. This approach offers students a richly contextual introduction to many of the fundamental tenets of the discipline. After a brief introduction to the field led by the faculty, the students themselves are…

  19. MALDI-TOFMS analysis of coordination and organometallic complexes: a nic(h)e area to work in.

    PubMed

    Wyatt, Mark F

    2011-07-01

    A mini-review of the characterisation of metal-containing compounds by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOFMS) is presented. Organometallic and coordination compounds have many varied applications, most notably in industrial catalytic processes and also in the electronics and healthcare sectors. In general, the compounds discussed, be they small or large molecules, have a high percentage metal content, rather than simply containing 'a metal atom'. A brief history of the field is given, but the main scope over the last 5 years is covered in some detail. How MALDI-TOFMS compliments electrospray for metal-containing compounds is highlighted. Perspectives on recent advances, such as solvent-free and air/moisture-sensitive sample preparation, and potential future challenges and developments, such as nanomaterials and metallodrug/metallometabolite imaging, are given. PMID:21744419

  20. Reaction mechanisms in the organometallic vapor phase epitaxial growth of GaAs

    NASA Technical Reports Server (NTRS)

    Larsen, C. A.; Buchan, N. I.; Stringfellow, G. B.

    1988-01-01

    The decomposition mechanisms of AsH3, trimethylgallium (TMGa), and mixtures of the two have been studied in an atmospheric-pressure flow system with the use of D2 to label the reaction products which are analyzed in a time-of-flight mass spectrometer. AsH3 decomposes entirely heterogeneously to give H2. TMGa decomposes by a series of gas-phase steps, involving methyl radicals and D atoms to produce CH3D, CH4, C2H6, and HD. TMGa decomposition is accelerated by the presence of AsH3. When the two are mixed, as in the organometallic vapor phase epitaxial growth of GaAs, both compounds decompose in concert to produce only CH4. A likely model is that of a Lewis acid-base adduct that forms and subsequently eliminates CH4.

  1. Iron-Catalyzed C-C Cross-Couplings Using Organometallics.

    PubMed

    Guérinot, Amandine; Cossy, Janine

    2016-08-01

    Over the last decades, iron-catalyzed cross-couplings have emerged as an important tool for the formation of C-C bonds. A wide variety of alkenyl, aryl, and alkyl (pseudo)halides have been coupled to organometallic reagents, the most currently used being Grignard reagents. Particular attention has been devoted to the development of iron catalysts for the functionalization of alkyl halides that are generally challenging substrates in classical cross-couplings. The high functional group tolerance of iron-catalyzed cross-couplings has encouraged organic chemists to use them in the synthesis of bioactive compounds. Even if some points remain obscure, numerous studies have been carried out to investigate the mechanism of iron-catalyzed cross-coupling and several hypotheses have been proposed. PMID:27573401

  2. A Study on the Abrasive Resistance of Ni Based Laser Coatings with WC Hard Phase

    NASA Astrophysics Data System (ADS)

    Iždinská, Zita; Brusilová, Alena; Iždinský, Karol

    2011-12-01

    Wear properties of composite laser cladding on the basis of Ni with a 50% presence of WC particles on the dependence of laser beam power output and speed of cladding were investigated in this paper. Properties are compared with reference Ni based laser claddings without WC particles. Laser beam power output of 4.3 and 3.7 kW and cladding speed of 3, 5 and 7 mm/s were used for the preparation of test pieces. All types of prepared claddings were compact without visible internal defects. With increased cladding speed, the hardness of Ni matrix decreased. Wear resistance of Ni based laser claddings with WC particles were dependent on the speed of laser cladding. The presence of WC particles increased the wear resistance of Ni based laser claddings 5 fold.

  3. A Review on Inertia and Linear Friction Welding of Ni-Based Superalloys

    NASA Astrophysics Data System (ADS)

    Chamanfar, Ahmad; Jahazi, Mohammad; Cormier, Jonathan

    2015-04-01

    Inertia and linear friction welding are being increasingly used for near-net-shape manufacturing of high-value materials in aerospace and power generation gas turbines because of providing a better quality joint and offering many advantages over conventional fusion welding and mechanical joining techniques. In this paper, the published works up-to-date on inertia and linear friction welding of Ni-based superalloys are reviewed with the objective to make clarifications on discrepancies and uncertainties reported in literature regarding issues related to these two friction welding processes as well as microstructure, texture, and mechanical properties of the Ni-based superalloy weldments. Initially, the chemical composition and microstructure of Ni-based superalloys that contribute to the quality of the joint are reviewed briefly. Then, problems related to fusion welding of these alloys are addressed with due consideration of inertia and linear friction welding as alternative techniques. The fundamentals of inertia and linear friction welding processes are analyzed next with emphasis on the bonding mechanisms and evolution of temperature and strain rate across the weld interface. Microstructural features, texture development, residual stresses, and mechanical properties of similar and dissimilar polycrystalline and single crystal Ni-based superalloy weldments are discussed next. Then, application of inertia and linear friction welding for joining Ni-based superalloys and related advantages over fusion welding, mechanical joining, and machining are explained briefly. Finally, present scientific and technological challenges facing inertia and linear friction welding of Ni-based superalloys including those related to modeling of these processes are addressed.

  4. The fragility of Al Ni-based glass-forming melts

    NASA Astrophysics Data System (ADS)

    Si, Pengchao; Bian, Xiufang; Zhang, Junyan; Li, Hui; Sun, Minhua; Zhao, Yan

    2003-08-01

    In the original description of fragility, Angell (1988 J. Phys. Chem. Solids 49 863) determined the degree of fragility from the curvature on an Arrhenius plot. This paper discusses a new measurement of the fragility value. The fragility of Al-Ni-based glass-forming melts, which is seldom reported in this field, can be analysed by using data from their viscosity and thermal properties. The fragility is observed to be very high, which is in very good agreement with the low glass-forming ability of Al-Ni-based alloys.

  5. Irradiation effects in oxide dispersion strengthened (ODS) Ni-base alloys for Gen. IV nuclear reactors

    NASA Astrophysics Data System (ADS)

    Oono, Naoko; Ukai, Shigeharu; Kondo, Sosuke; Hashitomi, Okinobu; Kimura, Akihiko

    2015-10-01

    Oxide particle dispersion strengthened (ODS) Ni-base alloys are irradiated by using simulation technique (Fe/He dual-ion irradiation) to investigate the reliability to Gen. IV high-temperature reactors. The fine oxide particles with less than 10 nm in average size and approximately 8.0 × 1022 m-3 in number density remained after 101 dpa irradiation. The tiny helium bubbles were inside grains, not at grain-boundaries; it is advantageous effect of oxide particles which trap the helium atoms at the particle-matrix interface. Ni-base ODS alloys demonstrated their great ability to overcome He embrittlement.

  6. Effects of Heat Treatments on Aluminum Oxide Coatings Deposited on Ni-BASED Alloy

    NASA Astrophysics Data System (ADS)

    Tang, Xiufeng; Luo, Fa; Hseih, Chunhan; Li, Xiangyu

    2015-12-01

    AlxOy films coated on both Ni-based superalloy and silica substrates were prepared by DC reactive magnetron sputtering. Post-deposition annealing was carried out on those as-deposited films. And then 1 h heat treatments were done on the annealed films at constant temperatures ranging from 600-900°C to simulate the high-temperature application. The AlxOy film heated at 600°C exhibited good film property. Bonding strength between the 600°C-heated AlxOy film and the Ni-based substrate was about 11.6 MPa.

  7. Effectiveness of various organometallics as antiwear additives in mineral oil

    NASA Technical Reports Server (NTRS)

    Buckley, D. H.

    1977-01-01

    Sliding friction experiments were conducted with 1045 steel contacting 302 stainless steel and lubricated with various organometallics in mineral oil. Auger emission spectroscopy was used to determine the element present in the wear contact zone. The results indicate that there are organometallics which are as effective an antiwear additives as the commonly used zinc dialkyl dithiophosphate. These include dimethyl cadmium, triphenyl lead thiomethoxide, and triphenyl tin chloride. The additives were examined in concentrations to 1 weight percent. With dimethyl cadmium at concentrations of 0.5 weight percent and above, cadmium was detected in the contact zone. Coincident with the detection of cadmium, a marked decrease in the friction coefficient was observed. All additives examined reduced friction, but only the aforementioned reduced wear to a level comparable to that observed with zinc dialkyl dithiophosphate.

  8. Supported organometallic complexes: Surface chemistry, spectroscopy, and catalysis

    SciTech Connect

    Marks, T.J.

    1991-01-01

    Adsorbing organometallic molecules onto the surfaces of inorganic supports such as Al{sub 2}O{sub 3}, MgCl{sub 2}, SiO{sub 2}, etc. can result in dramatic enhancements in catalytic activity. The reasons for this and the structures of the resulting surface organometallic centers are not well understood. We have addressed this problem using actinide and early transition metal complexes as model adsorbates. Characterization tools include catalytic and stoichiometric reaction chemistry, reaction kinetics and isotopic labeling, quantitative poisoning studies, model solution chemistry, and a wide array of surface-sensitive spectroscopies such as CPMAS NMR, EPR, and UV-VIS as well as titration calorimetry. These chemical and physical experiments are closely coupled to model solution chemistry to provide maximum information yield. 4 refs., 2 figs.

  9. Controlled Variable Oxidative Doping of Individual Organometallic Nanoparticles.

    PubMed

    Feng, Ann; Cheng, Wei; Holter, Jennifer; Young, Neil; Compton, Richard G

    2016-05-10

    The charging and controlled oxidative doping of single organometallic ferrocene nanoparticles is reported in aqueous sodium tetrafluoroborate using the nano-impacts method. It is shown that ferrocene nanoparticles of approximately 105 nm diameter are essentially quantitatively oxidatively doped with the uptake of one tetrafluoroborate anion per ferrocene molecule at suitably high overpotentials. By using lower potentials, it is possible to achieve low doping levels of single nanoparticles in a controlled manner. PMID:27038252

  10. An Organometallic Future in Green and Energy Chemistry?

    SciTech Connect

    Crabtree, Robert H

    2011-01-10

    The title topic is reviewed with selected examples taken from recent work, such as: the 'hydrogen borrowing' amine alkylation by alcohols; the dehydrogenative coupling of amine and alcohol to give amide; Ru complexes as solar cell photosensitizers; Ir organometallics as water oxidation catalyst precursors and as OLED emitters; as well as recent hydrogen storage strategies involving catalytic dehydrogenation of ammonia-borane and of organic heterocycles.

  11. New applications of Ziegler-Natta organometallic catalysts

    SciTech Connect

    Noskova, N.H.; Sokol'skii, D.V.

    1983-05-01

    The composition of Ziegler-Natta organometallic catalysts was discussed. These catalysts were found to be a set of definite complexes, including a polynuclear cluster complex, in dynamic equilibrium with each other. New applications were found for Ziegler-Natta catalysts, specifically, use for the mild activation of alkanes, reduction of carbon monoxide, and positional isomerization of unconjugated dienes into conjugated analogs which are promising in metal complex catalysis.

  12. Field-induced conductance switching by charge-state alternation in organometallic single-molecule junctions.

    PubMed

    Schwarz, Florian; Kastlunger, Georg; Lissel, Franziska; Egler-Lucas, Carolina; Semenov, Sergey N; Venkatesan, Koushik; Berke, Heinz; Stadler, Robert; Lörtscher, Emanuel

    2016-02-01

    Charge transport through single molecules can be influenced by the charge and spin states of redox-active metal centres placed in the transport pathway. These intrinsic properties are usually manipulated by varying the molecule's electrochemical and magnetic environment, a procedure that requires complex setups with multiple terminals. Here we show that oxidation and reduction of organometallic compounds containing either Fe, Ru or Mo centres can solely be triggered by the electric field applied to a two-terminal molecular junction. Whereas all compounds exhibit bias-dependent hysteresis, the Mo-containing compound additionally shows an abrupt voltage-induced conductance switching, yielding high-to-low current ratios exceeding 1,000 at bias voltages of less than 1.0 V. Density functional theory calculations identify a localized, redox-active molecular orbital that is weakly coupled to the electrodes and closely aligned with the Fermi energy of the leads because of the spin-polarized ground state unique to the Mo centre. This situation provides an additional slow and incoherent hopping channel for transport, triggering a transient charging effect in the entire molecule with a strong hysteresis and large high-to-low current ratios. PMID:26571004

  13. Computational Raman spectroscopy of organometallic reaction products in lithium and sodium-based battery systems.

    PubMed

    Sánchez-Carrera, Roel S; Kozinsky, Boris

    2014-11-28

    A common approach to understanding surface reaction mechanisms in rechargeable lithium-based battery systems involves spectroscopic characterization of the product mixtures and matching of spectroscopic features to spectra of pure candidate reference compounds. This strategy, however, requires separate chemical synthesis and accurate characterization of potential reference compounds. It also assumes that atomic structures are the same in the actual product mixture as in the reference samples. We propose an alternative approach that uses first-principles computations of spectra of the possible reaction products and by-products present in advanced battery systems. We construct a library of computed Raman spectra for possible products, achieving excellent agreement with reference experimental data, targeting solid-electrolyte interphase in Li-ion cells and discharge products of Li-air cells. However, the solid-state crystalline structure of Li(Na) metal-organic compounds is often not known, making the spectra computations difficult. We develop and apply a novel technique of simplifying spectra calculations by using dimer-like representations of the solid state structures. On the basis of a systematic investigation, we demonstrate that molecular dimers of Li(Na)-based organometallic material provide relevant information about the vibrational properties of many possible solid reaction products. Such an approach should serve as a basis to extend existing spectral libraries of molecular structures relevant for understanding the link between atomic structures and measured spectroscopic data of materials in novel battery systems. PMID:25310385

  14. Field-induced conductance switching by charge-state alternation in organometallic single-molecule junctions

    NASA Astrophysics Data System (ADS)

    Schwarz, Florian; Kastlunger, Georg; Lissel, Franziska; Egler-Lucas, Carolina; Semenov, Sergey N.; Venkatesan, Koushik; Berke, Heinz; Stadler, Robert; Lörtscher, Emanuel

    2016-02-01

    Charge transport through single molecules can be influenced by the charge and spin states of redox-active metal centres placed in the transport pathway. These intrinsic properties are usually manipulated by varying the molecule's electrochemical and magnetic environment, a procedure that requires complex setups with multiple terminals. Here we show that oxidation and reduction of organometallic compounds containing either Fe, Ru or Mo centres can solely be triggered by the electric field applied to a two-terminal molecular junction. Whereas all compounds exhibit bias-dependent hysteresis, the Mo-containing compound additionally shows an abrupt voltage-induced conductance switching, yielding high-to-low current ratios exceeding 1,000 at bias voltages of less than 1.0 V. Density functional theory calculations identify a localized, redox-active molecular orbital that is weakly coupled to the electrodes and closely aligned with the Fermi energy of the leads because of the spin-polarized ground state unique to the Mo centre. This situation provides an additional slow and incoherent hopping channel for transport, triggering a transient charging effect in the entire molecule with a strong hysteresis and large high-to-low current ratios.

  15. 2012 ORGANOMETALLIC CHEMISTRY GRC/GRS, JULY 7-13, 2012

    SciTech Connect

    Hillhouse, Gregory

    2012-07-13

    The 2012 Organometallic Chemistry Gordon Research Conference will highlight new basic science and fundamental applications of organometallic chemistry in industrial, academic, and national lab settings. Scientific themes of the conference will include chemical synthesis, reactivity, catalysis, polymer chemistry, bonding, and theory that involve transition-metal (and main-group) interactions with organic moieties.

  16. New Twists and Turns for Actinide Chemistry: Organometallic Infinite Coordination Polymers of Thorium Diazide.

    PubMed

    Monreal, Marisa J; Seaman, Lani A; Goff, George S; Michalczyk, Ryszard; Morris, David E; Scott, Brian L; Kiplinger, Jaqueline L

    2016-03-01

    Two organometallic 1D infinite coordination polymers and two organometallic monometallic complexes of thorium diazide have been synthesized and characterized. Steric control of these self-assembled arrays, which are dense in thorium and nitrogen, has also been demonstrated: infinite chains can be circumvented by using steric bulk either at the metallocene or with a donor ligand in the wedge. PMID:26865502

  17. Reactive codoping of GaAlInP compound semiconductors

    DOEpatents

    Hanna, Mark Cooper; Reedy, Robert

    2008-02-12

    A GaAlInP compound semiconductor and a method of producing a GaAlInP compound semiconductor are provided. The apparatus and method comprises a GaAs crystal substrate in a metal organic vapor deposition reactor. Al, Ga, In vapors are prepared by thermally decomposing organometallic compounds. P vapors are prepared by thermally decomposing phospine gas, group II vapors are prepared by thermally decomposing an organometallic group IIA or IIB compound. Group VIB vapors are prepared by thermally decomposing a gaseous compound of group VIB. The Al, Ga, In, P, group II, and group VIB vapors grow a GaAlInP crystal doped with group IIA or IIB and group VIB elements on the substrate wherein the group IIA or IIB and a group VIB vapors produced a codoped GaAlInP compound semiconductor with a group IIA or IIB element serving as a p-type dopant having low group II atomic diffusion.

  18. A synchrotron study of microstructure gradient in laser additively formed epitaxial Ni-based superalloy

    NASA Astrophysics Data System (ADS)

    Xue, Jiawei; Zhang, Anfeng; Li, Yao; Qian, Dan; Wan, Jingchun; Qi, Baolu; Tamura, Nobumichi; Song, Zhongxiao; Chen, Kai

    2015-10-01

    Laser additive forming is considered to be one of the promising techniques to repair single crystal Ni-based superalloy parts to extend their life and reduce the cost. Preservation of the single crystalline nature and prevention of thermal mechanical failure are two of the most essential issues for the application of this technique. Here we employ synchrotron X-ray microdiffraction to evaluate the quality in terms of crystal orientation and defect distribution of a Ni-based superalloy DZ125L directly formed by a laser additive process rooted from a single crystalline substrate of the same material. We show that a disorientation gradient caused by a high density of geometrically necessary dislocations and resultant subgrains exists in the interfacial region between the epitaxial and stray grains. This creates a potential relationship of stray grain formation and defect accumulation. The observation offers new directions on the study of performance control and reliability of the laser additive manufactured superalloys.

  19. A synchrotron study of microstructure gradient in laser additively formed epitaxial Ni-based superalloy

    PubMed Central

    Xue, Jiawei; Zhang, Anfeng; Li, Yao; Qian, Dan; Wan, Jingchun; Qi, Baolu; Tamura, Nobumichi; Song, Zhongxiao; Chen, Kai

    2015-01-01

    Laser additive forming is considered to be one of the promising techniques to repair single crystal Ni-based superalloy parts to extend their life and reduce the cost. Preservation of the single crystalline nature and prevention of thermal mechanical failure are two of the most essential issues for the application of this technique. Here we employ synchrotron X-ray microdiffraction to evaluate the quality in terms of crystal orientation and defect distribution of a Ni-based superalloy DZ125L directly formed by a laser additive process rooted from a single crystalline substrate of the same material. We show that a disorientation gradient caused by a high density of geometrically necessary dislocations and resultant subgrains exists in the interfacial region between the epitaxial and stray grains. This creates a potential relationship of stray grain formation and defect accumulation. The observation offers new directions on the study of performance control and reliability of the laser additive manufactured superalloys. PMID:26446425

  20. A synchrotron study of microstructure gradient in laser additively formed epitaxial Ni-based superalloy

    SciTech Connect

    Xue, Jiawei; Zhang, Anfeng; Li, Yao; Qian, Dan; Wan, Jingchun; Qi, Baolu; Tamura, Nobumichi; Song, Zhongxiao; Chen, Kai

    2015-10-08

    Laser additive forming is considered to be one of the promising techniques to repair single crystal Ni-based superalloy parts to extend their life and reduce the cost. Preservation of the single crystalline nature and prevention of thermal mechanical failure are two of the most essential issues for the application of this technique. Here we employ synchrotron X-ray microdiffraction to evaluate the quality in terms of crystal orientation and defect distribution of a Ni-based superalloy DZ125L directly formed by a laser additive process rooted from a single crystalline substrate of the same material. We show that a disorientation gradient caused by a high density of geometrically necessary dislocations and resultant subgrains exists in the interfacial region between the epitaxial and stray grains. This creates a potential relationship of stray grain formation and defect accumulation. In conclusion, the observation offers new directions on the study of performance control and reliability of the laser additive manufactured superalloys.

  1. Shape Memory Effects in TiNi-based Alloys Subjected to Electroplastic Rolling

    NASA Astrophysics Data System (ADS)

    Potapova, A. A.; Resnina, N. N.; Stolyarov, V. V.

    2014-07-01

    One of the prospective methods for structure refinement is electroplastic rolling (EPR). The use of an electric current pulse during cold rolling enhances deformability (1.5-3 times for TiNi-based alloys). It was shown that EPR ( e > 1) with post-deformation annealing at 450-500 °C leads to nanostructure formation with a grain size of 60-120 nm. Also, EPR leads to an increase in functional properties of TiNi-based alloys. So, the recovery coefficient was revealed as being better than the undeformed alloy (90-96% for Ti49,2Ni50,8 and 75-80% for Ti50,0Ni50,0). In the Ti50,0Ni50,0 subjected to EPR up to strain 3.6 and subsequent annealing at 450 °C for 1 h, the superelasticity effect is found.

  2. Discontinuous Precipitation in Ni-Base Superalloys During Solution Heat Treatment

    NASA Astrophysics Data System (ADS)

    Welton, D.; D'Souza, N.; Kelleher, J.; Gardner, S.; Dong, Z. H.; West, G. D.; Dong, Hongbiao

    2015-09-01

    Discontinuous precipitation in single-crystal Ni-base superalloys during solution heat treatment has been studied. It is found that discontinuous precipitation occurs at temperatures approaching the solvus, where volume diffusion is dominant. Diffusion of Al ahead of the boundary leads to gamma prime precipitation and is accompanied by a loss in the driving force available for advancement of the grain boundary. The rate of gamma prime precipitation was tracked using in situ neutron diffraction during isothermal hold. Gamma prime precipitation is accompanied by super-saturation of Cr and W within the channels ahead of the interface. The driving force calculated for the initial stages of DP was [10-5 to 10-4] N/[ μm2 of the grain boundary]. The results provide an insight into discontinuous precipitation during solution heat treatment of Ni-base single-crystal alloys and are useful in optimizing the heat treatment process to avoid surface defect formation.

  3. Estimation of conjugate gamma and gamma-prime compositions in Ni-base superalloys

    NASA Technical Reports Server (NTRS)

    Dreshfield, R. L.

    1977-01-01

    To control the formation of unwanted phases, superalloy metallurgists have developed methods of estimating the composition of the matrix phase of alloys. That composition is then used to estimate the alloy's propensity toward sigma and other unwanted phase formations upon prolonged exposure to elevated temperatures in service. This paper reviews two approaches for estimating phase composition from the melt composition. One method is based on assigning essentially fixed stoichiometry to precipitating phases and is typified by 'PHACOMP'. The second method uses analytical geometry to interpret phase diagrams and is shown to be applicable to a two-phase region of a six-component Ni-base system. The geometric method is also shown to be applicable to commercial Ni-base superalloys.

  4. Microstructural Stability and Hot Deformation of γ- γ'- δ Ni-Base Superalloys

    NASA Astrophysics Data System (ADS)

    Detrois, Martin; Helmink, Randolph C.; Tin, Sammy

    2014-11-01

    Nickel-base superalloys exhibit excellent high-temperature mechanical and physical properties and remain the first choice for structural components in advanced gas turbine engines for the aerospace propulsion and power generation applications. In response to the increasing demand for more efficient solutions and tighter requirements linked to gas turbine technologies, the properties of nickel-base superalloys can be improved by modification of their thermo-mechanical and/or compositional attributes. Recent investigations have revealed the potential use of ternary eutectic γ- γ'- δ Ni-base superalloys in advanced gas turbines due to high temperature mechanical properties that are comparable to state-of-the-art polycrystalline Ni-base superalloys. With properties largely dependent on microstructural strengthening mechanisms, both the composition and thermo-mechanical processing parameters of this novel class of alloys need to be optimized concurrently. The hot deformation characteristics of four γ- γ'- δ Ni-base superalloys with varying levels of Nb were evaluated at temperatures and strain rates between 1353 K and 1433 K (1080 °C and 1160 °C) and 0.01 to 0.001/s, respectively. Evidence of dislocation-based plasticity was observed following deformation at low temperatures and high strain rates, while high temperatures and low strain rates promoted superplasticity in these alloys. The extent of the microstructural changes and the magnitude of the cavitation damage which occurred during deformation was found to vary as a function of the alloy composition.

  5. Effects of Ta on microstructure and microhardness of Ni based laser clad coating

    NASA Astrophysics Data System (ADS)

    Yu, Ting; Deng, Qilin; Dong, Gang; Yang, Jianguo

    2011-03-01

    Through addition of Tantalum, fine TaC particles were in situ synthesized in a NiCrBSi alloy laser clad composite coating. Microstructure, microhardness and abrasive wear resistance of the composite coating were investigated. The result showed that TaC particles were dispersed in Ni based alloy composite coating, refining the microstructure of the coating after laser cladding. Amount of coarse primary carbides such as M7C3 and eutectic of γ-Ni + M23C6 substantially decreased because the formation of TaC particles suppressed the formation of M7C3 and M23C6. On the one hand, fine TaC particles acted as hard phase, which improved the microhardness of the composite coating; on the other hand, a decrease in amount of the coarse M7C3 and eutectic of γ-Ni + M23C6 reduced the crack susceptibility of the Ni based composite coating. Also, Ta element improved the abrasive wear resistance of the Ni based coating.

  6. Fundamental organometallic reactions: Applications on the CYBER 205

    NASA Technical Reports Server (NTRS)

    Rappe, A. K.

    1984-01-01

    Two of the most challenging problems of Organometallic chemistry (loosely defined) are pollution control with the large space velocities needed and nitrogen fixation, a process so capably done by nature and so relatively poorly done by man (industry). For a computational chemist these problems are on the fringe of what is possible with conventional computers (large models needed and accurate energetics required). A summary of the algorithmic modification needed to address these problems on a vector processor such as the CYBER 205 and a sketch of findings to date on deNOx catalysis and nitrogen fixation are presented.

  7. Electronic configurations and magnetic anisotropy in organometallic metallocenes

    NASA Astrophysics Data System (ADS)

    Nawa, Kenji; Kitaoka, Yukie; Nakamura, Kohji; Akiyama, Toru; Ito, Tomonori

    2015-05-01

    Electronic configurations and magnetic anisotropy of organometallic metallocenes (MCp2s) were investigated by means of first principles calculations based on the constraint density functional theory. The results predict that the ground states for M = Cr, Mn, Fe, Co, and Ni are the 3E2 g, 2E2 g, 1A1 g, 2E1 g, and 3A2 g states, respectively. The magnetizations of the CoCp2 and NiCp2 energetically favor highly orienting along the perpendicular and parallel directions to the cyclopentadienyl (Cp) plane, respectively, and the others show almost no preference for the magnetic easy axis.

  8. Tabletop Extreme Ultraviolet Spectroscopy of Element-Specific Organometallic Photophysics

    NASA Astrophysics Data System (ADS)

    Vura-Weis, Josh

    High-harmonic extreme ultraviolet (XUV) spectroscopy has the potential to provide the elemental, oxidation-state, and spin-state specificity of core-level spectroscopy with the convenience and ultrafast time resolution of tabletop laser sources. We will show that M-edge spectroscopy of first-row transition metal complexes (3p -->3d excitation) is a sensitive probe of the electronic structure of organometallic complexes in solution. Furthermore, this technique can be used to determine the relaxation dynamics of these molecules in the first few femtoseconds to nanoseconds after photoexcitation.

  9. High-valent organometallic copper and palladium in catalysis.

    PubMed

    Hickman, Amanda J; Sanford, Melanie S

    2012-04-12

    Copper and palladium catalysts are critically important in numerous commercial chemical processes. Improvements in the activity, selectivity and scope of these catalysts could drastically reduce the environmental impact, and increase the sustainability, of chemical reactions. One rapidly developing strategy for achieving these goals is to use 'high-valent' organometallic copper and palladium intermediates in catalysis. Here we describe recent advances involving both the fundamental chemistry and the applications of these high-valent metal complexes in numerous synthetically useful catalytic transformations. PMID:22498623

  10. CVD Of Thin Films From Single Organometallic Precursors

    NASA Technical Reports Server (NTRS)

    Hepp, Aloysius F.; Barron, Andrew R.; Power, Michael B.; Macinnes, Andrew N.; Jenkins, Phillip P.

    1996-01-01

    Method of forming thin inorganic films involves chemical vapor deposition (CVD) from single organometallic precursors. No toxic constituents, minimizes impurities, and yields films having substantially uniform crystal structure and composition. Especially suitable for depositing high-quality passivating or buffer layers of GaS on GaAs semiconductor substrates. Also applicable to formation of high-quality films for purposes other than buffering or passivation, and to different materials in which another element from same group in periodic table of elements substituted for all or portion of each element in GaS/GaAs system.

  11. Supported organometallic complexes: Surface chemistry, spectroscopy, and catalysis

    SciTech Connect

    Marks, T.J.

    1992-02-01

    The long-range goal of this project is to elucidate and understand the surface chemistry and catalytic properties of well-defined, highly-reactive organometallic molecules (principally based upon abundant actinide, lanthanide, and early transition elements) adsorbed on metal oxides and halides. The nature of the adsorbed species is probed by a battery of chemical and physicochemical techniques, to understand the nature of the molecular-surface coordination chemistry and how this can give rise to extremely high catalytic activity. A complementary objective is to delineate the scope and mechanisms of the heterogeneous catalytic reactions, as well as to relate them both conceptually and functionally to model systems generated in solution.

  12. Antitumor and biological investigation of doubly cyclometalated ruthenium(ii) organometallics derived from benzimidazolyl derivatives.

    PubMed

    Elumalai, Palani; Jeong, Yong Joon; Park, Dae Won; Kim, Dong Hwan; Kim, Hyunuk; Kang, Se Chan; Chi, Ki-Whan

    2016-04-12

    In this study, we report the synthesis, anticancer and biological properties of three doubly cyclometalated phenylbenzimidazole derived ruthenium(ii) organometallics () and their corresponding three organic ligands. The structures of were fully characterized by various analytical techniques, and the meso stereoisomer of the doubly cyclometalated ruthenacycle was unambiguously confirmed by single crystal X-ray diffraction. The anticancer effects of the newly synthesized compounds were tested against selected human cancer cell lines AGS (gastric carcinoma), SK-hep-1 (hepatocellular carcinoma), and HCT-15 (colorectal carcinoma). The growth inhibitory effects of ruthenacycles on cancer cells were found to be considerably more effective against the abovementioned cancer cells than the reference drug oxaliplatin. Compound exhibited a more specific effect on the AGS cells. Gene-fishing and ELISA array were performed to analyze the target genes and cytokine secretion by . As a result, a significant reduction was observed in RPS21 by . Moreover, increased the secretion of cytokines such as IFNγ in macrophages and reduced the release of cytokines such as rantes and IGF-1. These results show that could be a very good anticancer drug through the regulation of the RPS21 gene and cytokines. PMID:26974823

  13. Towards cancer cell-specific phototoxic organometallic rhenium(I) complexes.

    PubMed

    Leonidova, Anna; Pierroz, Vanessa; Rubbiani, Riccardo; Heier, Jakob; Ferrari, Stefano; Gasser, Gilles

    2014-03-21

    Over the recent years, several Re(I) organometallic compounds have been shown to be toxic to various cancer cell lines. However, these compounds lacked sufficient selectivity towards cancer tissues to be used as novel chemotherapeutic agents. In this study, we probe the potential of two known N,N-bis(quinolinoyl) Re(I) tricarbonyl complex derivatives, namely Re(I) tricarbonyl [N,N-bis(quinolin-2-ylmethyl)amino]-4-butane-1-amine (Re-NH₂) and Re(I) tricarbonyl [N,N-bis(quinolin-2-ylmethyl)amino]-5-valeric acid (Re-COOH), as photodynamic therapy (PDT) photosensitizers. Re-NH₂ and Re-COOH proved to be excellent singlet oxygen generators in a lipophilic environment with quantum yields of about 75%. Furthermore, we envisaged to improve the selectivity of Re-COOH via conjugation to two types of peptides, namely a nuclear localization signal (NLS) and a derivative of the neuropeptide bombesin, to form Re-NLS and Re-Bombesin, respectively. Fluorescent microscopy on cervical cancer cells (HeLa) showed that the conjugation of Re-COOH to NLS significantly enhanced the compound's accumulation into the cell nucleus and more specifically into its nucleoli. Importantly, in view of PDT applications, the cytotoxicity of the Re complexes and their bioconjugates increased significantly upon light irradiation. In particular, Re-Bombesin was found to be at least 20-fold more toxic after light irradiation. DNA photo-cleavage studies demonstrated that all compounds damaged DNA via singlet oxygen and, to a minor extent, superoxide production. PMID:23982882

  14. Two-Photon Absorption in Organometallic Bromide Perovskites.

    PubMed

    Walters, Grant; Sutherland, Brandon R; Hoogland, Sjoerd; Shi, Dong; Comin, Riccardo; Sellan, Daniel P; Bakr, Osman M; Sargent, Edward H

    2015-09-22

    Organometallic trihalide perovskites are solution-processed semiconductors that have made great strides in third-generation thin film light-harvesting and light-emitting optoelectronic devices. Recently, it has been demonstrated that large, high-purity single crystals of these perovskites can be synthesized from the solution phase. These crystals' large dimensions, clean bandgap, and solid-state order have provided us with a suitable medium to observe and quantify two-photon absorption in perovskites. When CH3NH3PbBr3 single crystals are pumped with intense 800 nm light, we observe band-to-band photoluminescence at 572 nm, indicative of two-photon absorption. We report the nonlinear absorption coefficient of CH3NH3PbBr3 perovskites to be 8.6 cm GW(-1) at 800 nm, comparable to epitaxial single-crystal semiconductors of similar bandgap. We have leveraged this nonlinear process to electrically autocorrelate a 100 fs pulsed laser using a two-photon perovskite photodetector. This work demonstrates the viability of organometallic trihalide perovskites as a convenient and low-cost nonlinear absorber for applications in ultrafast photonics. PMID:26196162

  15. Polymeric Micelle-Mediated Delivery of DNA-Targeting Organometallic Complexes for Resistant Ovarian Cancer Treatment.

    PubMed

    Duan, Xiaopin; Liu, Demin; Chan, Christina; Lin, Wenbin

    2015-08-26

    Three half-sandwich iridium and ruthenium organometallic complexes with high cytotoxicity are synthesized, and their anticancer mechanisms are elucidated. The organometallic complexes can interact with DNA through coordination or intercalation, thereby inducing apoptosis and inhibiting proliferation of resistant cancer cells. The organometallic complexes are then incorporated into polymeric micelles through the polymer-metal coordination between poly(ethylene glycol)-b-poly(glutamic acid) [PEG-b-P(Glu)] and organometallic complexes to further enhance their anticancer effects as a result of the enhanced permeability and retention effect. The micelles with particle sizes of ≈60 nm are more efficiently internalized by cancer cells than the corresponding complexes, and selectively dissociate and release organometallic anticancer agents within late endosomes and lysosomes, thereby enhancing drug delivery to the nuclei of cancer cells and facilitating their interactions with DNA. Thus, the micelles display higher antitumor activity than the organometallic complexes alone with a lack of the systemic toxicity in a mouse xenograft model of cisplatin-resistant human ovarian cancer. These results suggest that the polymeric micelles carrying anticancer organometallic complexes provide a promising platform for the treatment of resistant ovarian cancer and other hard-to-treat solid tumors. PMID:25963931

  16. Development of ultrafast photochromic organometallics and photoinduced linkage isomerization of arene chromium carbonyl derivatives.

    PubMed

    To, Tung T; Heilweil, Edwin J; Duke, Charles B; Ruddick, Kristie R; Webster, Charles Edwin; Burkey, Theodore J

    2009-03-26

    We review recent studies of processes relevant to photoinduced linkage isomerization of organometallic systems with the goal of preparing organometallics with an efficient and ultrafast photochromic response. The organometallic system thus corresponds to two linkage isomers with different electronic environments that are responsible for different optical properties. Much of this work has focused on examining processes following irradiation of cyclopentadienyl manganese tricarbonyl derivatives (compounds 3-21) including solvent coordination, thermal relaxation, solvent displacement by tethered functional groups (chelation), dissociation of tethered functional groups, and linkage isomerization. A new platform is investigated for obtaining a photochromic response in new experiments with arene chromium dicarbonyl complexes. A photochromic response is observed for arene chromium dicarbonyl complexes with tethered pyridine and olefin functional groups based on light-driven linkage isomerization on the nanosecond time scale. Irradiation at 532 nm of 23 ([Cr{eta(6)-C(6)H(5)CH(2-Py-kappaN)CH(2)CH=CH(2)}(CO)(2)]) (Py = pyridine) results in the isomerization to 22 ([Cr{eta(6)-C(6)H(5)CH(2-Py)CH(2)-eta(2)-CH=CH(2)}(CO)(2)]), and 355 nm irradiation isomerizes 22 to 23. The ultrafast linkage isomerization has been investigated at room temperature in n-heptane solution on the picosecond to microsecond time scale with UV- or visible-pump and IR-probe transient absorption spectroscopy by comparing the dynamics with model compounds containing only a tethered pyridine. Irradiation of 24 ([Cr{eta(6)-C(6)H(5)(CH(2))(3)(2-Py)}(CO)(3)]) and 25 ([Cr{eta(6)-C(6)H(5)(CH(2))(2)(2-Py)}(CO)(3)]) at 289 nm induces CO loss to immediately yield a Cr-heptane solvent coordinated intermediate of the unsaturated Cr fragment, which then converts to the kappaN(1)-pyridine chelate within 200 and 100 ns, respectively. Irradiation of 26 ([Cr{eta(6)-C(6)H(5)CH(2)(2-Py)}(CO)(3)]) also induces CO loss to

  17. Investigation on corrosion and wear behaviors of nanoparticles reinforced Ni-based composite alloying layer

    NASA Astrophysics Data System (ADS)

    Xu, Jiang; Tao, Jie; Jiang, Shuyun; Xu, Zhong

    2008-04-01

    In order to investigate the role of amorphous SiO 2 particles in corrosion and wear resistance of Ni-based metal matrix composite alloying layer, the amorphous nano-SiO 2 particles reinforced Ni-based composite alloying layer has been prepared by double glow plasma alloying on AISI 316L stainless steel surface, where Ni/amorphous nano-SiO 2 was firstly predeposited by brush plating. The composition and microstructure of the nano-SiO 2 particles reinforced Ni-based composite alloying layer were analyzed by using SEM, TEM and XRD. The results indicated that the composite alloying layer consisted of γ-phase and amorphous nano-SiO 2 particles, and under alloying temperature (1000 °C) condition, the nano-SiO 2 particles were uniformly distributed in the alloying layer and still kept the amorphous structure. The corrosion resistance of composite alloying layer was investigated by an electrochemical method in 3.5%NaCl solution. Compared with single alloying layer, the amorphous nano-SiO 2 particles slightly decreased the corrosion resistance of the Ni-Cr-Mo-Cu alloying layer. X-ray photoelectron spectroscopy (XPS) revealed that the passive films formed on the composite alloying consisted of Cr 2O 3, MoO 3, SiO 2 and metallic Ni and Mo. The dry wear test results showed that the composite alloying layer had excellent friction-reduced property, and the wear weight loss of composite alloying layer was less than 60% of that of Ni-Cr-Mo-Cu alloying layer.

  18. Potential and limitations of microanalysis SEM techniques to characterize borides in brazed Ni-based superalloys

    SciTech Connect

    Ruiz-Vargas, J.; Siredey-Schwaller, N.; Noyrez, P.; Mathieu, S.; Bocher, P.; and others

    2014-08-15

    Brazed Ni-based superalloys containing complex phases of different Boron contents remain difficult to characterize at the micrometer scale. Indeed Boron is a light element difficult to measure precisely. The state-of-the-art microanalysis systems have been tested on a single crystal MC2 based metal brazed with BNi-2 alloy to identify boride precipitates. Effort has been made to evaluate the accuracy in Boron quantitation. Energy-dispersive and wavelength-dispersive X-ray spectroscopy attached to a Scanning Electron Microscope have first been used to determine the elemental composition of Boron-free phases, and then applied to various types of borides. Results have been compared to the ones obtained using a dedicated electron probe microanalysis, considered here as the reference technique. The most accurate method to quantify Boron using EDS is definitely by composition difference. A precision of 5 at.% could be achieved with optimized data acquisition and post-processing schemes. Attempts that aimed at directly quantifying Boron with various standards using EDS or coupled EDS/WDS gave less accurate results. Ultimately, Electron Backscatter Diffraction combined with localized EDS analysis has proved invaluable in conclusively identifying micrometer sized boride precipitates; thus further improving the characterization of brazed Ni-based superalloys. - Highlights: • We attempt to accurately identify Boron-rich phases in Ni-based superalloys. • EDS, WDS, EBSD systems are tested for accurate identification of these borides. • Results are compared with those obtained by electron probe microanalysis. • Boron was measured with EDS by composition difference with a precision of 5 at. %. • Additional EBSD in phase identification mode conclusively identifies the borides.

  19. Precipitate Phase Stability in γ- γ'- δ- η Ni-Base Superalloys

    NASA Astrophysics Data System (ADS)

    Detrois, Martin; Antonov, Stoichko; Helmink, Randolph C.; Tin, Sammy

    2014-12-01

    In response to the increasing temperature capability of the structural materials required for advanced gas turbine engines, new alloying concepts are required to develop materials with properties that are significantly better than existing nickel-base superalloys. Recent investigations have focused on the development of polycrystalline, ternary eutectic γ- γ'- δ Ni-base superalloys that use large volume fractions of the intermetallic δ phase to provide composite strengthening. While compositional changes enabled the formation of the δ phase precipitates, in some alloys an additional precipitate phase η was formed. As the effects of these phases on high-temperature mechanical properties are not well quantified, a better understanding of the thermodynamics and kinetics associated with the formation of these δ and η phase precipitates is required for future designs of Ni-base superalloys. A set of experimental alloys was investigated to understand the formation of the δ and η phase precipitates in Ni-base superalloys. When the alloy chemistry was observed to exhibit a compositional ratio of Al/(Nb+Ta+Ti) less than 1, δ and/or η phase precipitates formed, whereas a ratio greater than 1 resulted in conventional γ- γ' microstructures. For alloys in which δ and/or η phase precipitates were formed, the prevalent phase could be determined by evaluating the compositional ratio for (Nb+Ta)/(Al+Ti). Alloys that had ratios greater than 1 were largely composed of δ phase precipitates, whereas a ratio less than 1 resulted in the predominance of the η phase precipitates.

  20. Creep Damage Process of Ni-Base Superalloy Caused by Stress-Induced Anisotropic Atomic Diffusion

    NASA Astrophysics Data System (ADS)

    Suzuki, Ken; Ito, Hiroyuki; Inoue, Tatsuya; Miura, Hideo

    In order to make clear the mechanism of the directional coarsening of γ' phases (rafting) of Ni-base superalloy under uni-axial strain, molecular dynamics (MD) analysis was applied to analyze the effect of strain on the diffusion characteristics around the interface between different materials. In a Ni (001)/Al (001) interface structure, the stress induced diffusion of Al atoms perpendicular to the interface was found. The stress induced anisotropic diffusion of Al was also found in a Ni (001)/Ni3Al (001) interface. These results imply that it is highly possible the rafting occurs predominantly by the stress induced anisotropic diffusion of Al atoms.

  1. Measuring Depth-dependent Dislocation Densities and Elastic Strains in an Indented Ni-based Superalloy

    SciTech Connect

    Barabash, O.M.; Santella, M.; Barabash, R.I.; Ice, G.E.; Tischler, J.

    2011-12-14

    The indentation-induced elastic-plastic zone in an IN 740 Ni-based superalloy was studied by three-dimensional (3-D) x-ray microdiffraction and electron back scattering diffraction (EBSD). Large lattice reorientations and the formation of geometrically necessary dislocations are observed in the area with a radius of {approx}75 {mu}m. A residual compression zone is found close to the indent edge. An elastic-plastic transition is observed at {approx}20 {mu}m from the indent edge. Depth dependent dislocation densities are determined at different distances from the indent edge.

  2. Single and multijunction space solar cells grown by organometallic vapor phase epitaxy (OM-VPE)

    SciTech Connect

    Borden, P.G.; Gregory, P.E.; Larue, R.A.; Ludowise, M.J.

    1982-08-01

    Organometallic Vapor Phase Epitaxy (OM-VPE) is a versatile technique for growing III-V compound semiconductor solar cells. It has good uniformity and morphology, control that allows growth of extremely thin layers, and is a technique readily automated. The vehicle for the present discussion is a metal interconnected cascade (MIC/sup 2/) solar cell that has achieved 16.6% AM0 and 22% AM3 efficiency (uncorrected for 14% grid coverage). These are the best results reported to date for a cascade solar cell. Features include a 9-layer epitaxial structure, the thinnest of which is less than 1000 thick, a high-efficiency 30% AlGaAs top cell only 1.5 microns thick, a GaAs bottom cell that has survived the 780/sup 0/C, 20-minute top cell growth, and process yields greater than 4 cm/sup 2/ per wafer. The paper describes the cell design requirements, how it was grown by OM-VPE, and performance results.

  3. Effect of organometallic fuel additives on nanoparticle emissions from a gasoline passenger car.

    PubMed

    Gidney, Jeremy T; Twigg, Martyn V; Kittelson, David B

    2010-04-01

    Particle size measurements were performed on the exhaust of a car operating on a chassis dynamometer fueled with standard gasoline and gasoline containing low levels of Pb, Fe, and Mn organometallic additives. When additives were present there was a distinct nucleation mode consisting primarily of sub-10 nm nanoparticles. At equal molar dosing Mn and Fe gave similar nanoparticle concentrations at the tailpipe, whereas Pb gave a considerably lower concentration. A catalytic stripper was used to remove the organic component of these particles and revealed that they were mainly solid and, because of their association with inorganic additives, presumably inorganic. Solid nucleation mode nanoparticles of similar size and concentration to those observed here from a gasoline engine with Mn and Fe additives have also been observed from modern heavy-duty diesel engines without aftertreatment at idle, but these solid particles are a small fraction of the primarily volatile nucleation mode particles emitted. The solid nucleation mode particles emitted by the diesel engines are likely derived from metal compounds in the lubrication oil, although carbonaceous particles cannot be ruled out. Significantly, most of these solid nanoparticles emitted by both engine types fall below the 23 nm cutoff of the PMP number regulation. PMID:20192164

  4. Selective Organic and Organometallic Reactions in Water-Soluble Host-Guest Supramolecular Systems

    SciTech Connect

    Pluth, Michael D.; Raymond, Kenneth N.; Bergman, Robert G.

    2008-02-16

    Inspired by the efficiency and selectivity of enzymes, synthetic chemists have designed and prepared a wide range of host molecules that can bind smaller molecules with their cavities; this area has become known as 'supramolecular' or 'host-guest' chemistry. Pioneered by Lehn, Cram, Pedersen, and Breslow, and followed up by a large number of more recent investigators, it has been found that the chemical environment in each assembly - defined by the size, shape, charge, and functional group availability - greatly influences the guest-binding characteristics of these compounds. In contrast to the large number of binding studies that have been carried out in this area, the exploration of chemistry - especially catalytic chemistry - that can take place inside supramolecular host cavities is still in its infancy. For example, until the work described here was carried out, very few examples of organometallic reactivity inside supramolecular hosts were known, especially in water solution. For that reason, our group and the group directed by Kenneth Raymond decided to take advantage of our complementary expertise and attempt to carry out metal-mediated C-H bond activation reactions in water-soluble supramolecular systems. This article begins by providing background from the Raymond group in supramolecular coordination chemistry and the Bergman group in C-H bond activation. It goes on to report the results of our combined efforts in supramolecular C-H activation reactions, followed by extensions of this work into a wider range of intracavity transformations.

  5. Entrapment of an organometallic complex within a metal: a concept for heterogeneous catalysis.

    PubMed

    Yosef, Itzik; Abu-Reziq, Raed; Avnir, David

    2008-09-10

    A novel family of composite materials, organically doped metals, has been recently introduced. Here, we demonstrate their use as a new platform for heterogeneous catalysis, namely the doping of a metal with a catalytic organometallic complex. Specifically, a rhodium(I) catalyst, (RhCl(COD)(Ph2P(C6H4SO3Na))), ([Rh]), was physically entrapped within silver, thus creating a new type of catalytic material: [Rh]@Ag. Several aspects were demonstrated with the development of this heterogeneous catalyst: a metal can be used as a support for heterogenizing a homogeneous catalyst; the homogeneous catalyst is stabilized by the entrapment within the metal; the products of the composite catalyst are different compared to those obtained from the homogeneous one; and the adsorption of [Rh] on the surface of Ag and its entrapment are very different processes only the latter provided appreciable catalytic activity. Thus, while homogeneous [Rh] was entirely destroyed after converting styrene to ethylbenzne at 50%, [Rh]@Ag remained active after effecting the same reaction to a yield of 85% (compared to only 7% for [Rh] adsorbed on Ag), and while homogeneous [Rh] hydrogenated diphenylacetylene to bibenzyl (and was completely deactivated after one cycle) with no trace of cis-stilbene, [Rh]@Ag afforded that compound as the main product and could be reused. PMID:18702492

  6. CVD of SiC and AlN using cyclic organometallic precursors

    NASA Technical Reports Server (NTRS)

    Interrante, L. V.; Larkin, D. J.; Amato, C.

    1992-01-01

    The use of cyclic organometallic molecules as single-source MOCVD precursors is illustrated by means of examples taken from our recent work on AlN and SiC deposition, with particular focus on SiC. Molecules containing (AlN)3 and (SiC)2 rings as the 'core structure' were employed as the source materials for these studies. The organoaluminum amide, (Me2AlNH2)3, was used as the AlN source and has been studied in a molecular beam sampling apparatus in order to determine the gas phase species present in a hot-wall CVD reactor environment. In the case of SiC CVD, a series of disilacyclobutanes (Si(XX')CH2)2 (with X and X' = H, CH3, and CH2SiH2CH3), were examined in a cold-wall, hot-stage CVD reactor in order to compare their relative reactivities and prospective utility as single-source CVD precursors. The parent compound, disilacyclobutane, (SiH2CH2)2, was found to exhibit the lowest deposition temperature (ca. 670 C) and to yield the highest purity SiC films. This precursor gave a highly textured, polycrystalline film on the Si(100) substrates.

  7. Novel Two- and Three-Dimensional Organometallic-Organic Hybrid Materials Based on Polyphosphorus Complexes.

    PubMed

    Attenberger, Bianca; Peresypkina, Eugenia V; Scheer, Manfred

    2015-07-20

    The reaction of the silver salt Ag[Al{OC(CF3)3}4] (1) with the P2 ligand complex [Cp2Mo2(CO)4(η(2)-P2)] (2) and the organic ditopic linker trans-1,2-di(pyridine-4-yl)ethene (dpe) results in the formation of four novel organometallic-organic hybrid compounds. Depending on the reaction conditions, the two-dimensional networks [{Cp2Mo2(CO)4(μ4,η(1:1:2:2)-P2)}(μ,η(1:1)-C12H10N2)Ag]n[Al{OC(CF3)3}4]n·0.075nCH2Cl2·1.425nC6H6 (3) and [{Cp2Mo2(CO)4(μ3,η(2:2:2)-P2)}2(μ,η(1:1)-C12H10N2)3Ag2]n[Al{OC(CF3)3}4]2n·2nC7H8 (4) are accessible. The latter shows a two-dimensional (2D) → 2D interpenetration structure. Furthermore, the formation of a unique three-dimensional polymer [{Cp2Mo2(CO)4(μ4,η(1:1:2:2)-P2)}(μ,η(1:1)-C12H10N2)Ag]n[Al{OC(CF3)3}4]n·0.3nCH2Cl2 (5b) together with another 2D polymer [{Cp2Mo2(CO)4(μ4,η(1:1:2:2)-P2)}(μ,η(1:1)-C12H10N2)3Ag2]n[Al{OC(CF3)3}4]2n·0.75CH2Cl2·0.5C7H8 (5a) was observed. In three of these polymers, unprecedented organometallic nodes were realized including one, two, or even four silver cations. All products were characterized by X-ray structural analysis and classified by the structural characteristics in three different network topologies. PMID:26121218

  8. Supported organometallic complexes: Surface chemistry, spectroscopy, and catalysis. Progress report, March 15, 1988--July 14, 1989

    SciTech Connect

    Marks, T.J.

    1990-02-01

    The goal of our program is to define those modes of interaction that take place between organometallic molecules and inorganic surfaces and, ultimately, to correlate various molecule-surface structures with catalytic properties.

  9. Laser Direct Writing of Conductive Silver Film on Polyimide Surface from Decomposition of Organometallic Ink

    NASA Astrophysics Data System (ADS)

    Cai, Zhixiang; Zeng, Xiaoyan; Liu, Jianguo

    2011-03-01

    Laser direct writing of organometallic ink to manufacture silver films was investigated by using a continuous-wave, Yb-doped fiber laser beam at a wavelength of 1071 nm. The organometallic ink consisted of an organometallic silver complex and a carrier vehicle, which was prepared by reaction of silver oxide with ammonium carbamates in methanol. The organometallic silver decomposed at a laser power of 0.1 W. The electrical resistivity values of silver conductors that were fabricated at a laser power of 0.5 W were about four times that of bulk silver. The morphology and electrical properties of the silver film were observed to be controllable as a function of laser processing parameters. The fabricated silver film exhibited excellent adherence to the polyimide substrate surface according to evaluation using the peel-off testing method.

  10. Organometallic Iridium(III) Anticancer Complexes with New Mechanisms of Action: NCI-60 Screening, Mitochondrial Targeting, and Apoptosis

    PubMed Central

    2013-01-01

    Platinum complexes related to cisplatin, cis-[PtCl2(NH3)2], are successful anticancer drugs; however, other transition metal complexes offer potential for combating cisplatin resistance, decreasing side effects, and widening the spectrum of activity. Organometallic half-sandwich iridium (IrIII) complexes [Ir(Cpx)(XY)Cl]+/0 (Cpx = biphenyltetramethylcyclopentadienyl and XY = phenanthroline (1), bipyridine (2), or phenylpyridine (3)) all hydrolyze rapidly, forming monofunctional G adducts on DNA with additional intercalation of the phenyl substituents on the Cpx ring. In comparison, highly potent complex 4 (Cpx = phenyltetramethylcyclopentadienyl and XY = N,N-dimethylphenylazopyridine) does not hydrolyze. All show higher potency toward A2780 human ovarian cancer cells compared to cisplatin, with 1, 3, and 4 also demonstrating higher potency in the National Cancer Institute (NCI) NCI-60 cell-line screen. Use of the NCI COMPARE algorithm (which predicts mechanisms of action (MoAs) for emerging anticancer compounds by correlating NCI-60 patterns of sensitivity) shows that the MoA of these IrIII complexes has no correlation to cisplatin (or oxaliplatin), with 3 and 4 emerging as particularly novel compounds. Those findings by COMPARE were experimentally probed by transmission electron microscopy (TEM) of A2780 cells exposed to 1, showing mitochondrial swelling and activation of apoptosis after 24 h. Significant changes in mitochondrial membrane polarization were detected by flow cytometry, and the potency of the complexes was enhanced ca. 5× by co-administration with a low concentration (5 μM) of the γ-glutamyl cysteine synthetase inhibitor L-buthionine sulfoximine (L-BSO). These studies reveal potential polypharmacology of organometallic IrIII complexes, with MoA and cell selectivity governed by structural changes in the chelating ligands. PMID:23618382

  11. Organometallic Iridium(III) anticancer complexes with new mechanisms of action: NCI-60 screening, mitochondrial targeting, and apoptosis.

    PubMed

    Hearn, Jessica M; Romero-Canelón, Isolda; Qamar, Bushra; Liu, Zhe; Hands-Portman, Ian; Sadler, Peter J

    2013-01-01

    Platinum complexes related to cisplatin, cis-[PtCl2(NH3)2], are successful anticancer drugs; however, other transition metal complexes offer potential for combating cisplatin resistance, decreasing side effects, and widening the spectrum of activity. Organometallic half-sandwich iridium (Ir(III)) complexes [Ir(Cp(x))(XY)Cl](+/0) (Cp(x) = biphenyltetramethylcyclopentadienyl and XY = phenanthroline (1), bipyridine (2), or phenylpyridine (3)) all hydrolyze rapidly, forming monofunctional G adducts on DNA with additional intercalation of the phenyl substituents on the Cp(x) ring. In comparison, highly potent complex 4 (Cp(x) = phenyltetramethylcyclopentadienyl and XY = N,N-dimethylphenylazopyridine) does not hydrolyze. All show higher potency toward A2780 human ovarian cancer cells compared to cisplatin, with 1, 3, and 4 also demonstrating higher potency in the National Cancer Institute (NCI) NCI-60 cell-line screen. Use of the NCI COMPARE algorithm (which predicts mechanisms of action (MoAs) for emerging anticancer compounds by correlating NCI-60 patterns of sensitivity) shows that the MoA of these Ir(III) complexes has no correlation to cisplatin (or oxaliplatin), with 3 and 4 emerging as particularly novel compounds. Those findings by COMPARE were experimentally probed by transmission electron microscopy (TEM) of A2780 cells exposed to 1, showing mitochondrial swelling and activation of apoptosis after 24 h. Significant changes in mitochondrial membrane polarization were detected by flow cytometry, and the potency of the complexes was enhanced ca. 5× by co-administration with a low concentration (5 μM) of the γ-glutamyl cysteine synthetase inhibitor L-buthionine sulfoximine (L-BSO). These studies reveal potential polypharmacology of organometallic Ir(III) complexes, with MoA and cell selectivity governed by structural changes in the chelating ligands. PMID:23618382

  12. Flat Chern band in a two-dimensional organometallic framework.

    PubMed

    Liu, Zheng; Wang, Zheng-Fei; Mei, Jia-Wei; Wu, Yong-Shi; Liu, Feng

    2013-03-01

    By combining exotic band dispersion with nontrivial band topology, an interesting type of band structure, namely, the flat Chern band, has recently been proposed to spawn high-temperature fractional quantum Hall states. Despite the proposal of several theoretical lattice models, however, it remains doubtful whether such a "romance of flatland" could exist in a real material. Here, we present a first-principles design of a two-dimensional indium-phenylene organometallic framework that realizes a nearly flat Chern band right around the Fermi level by combining lattice geometry, spin-orbit coupling, and ferromagnetism. An effective four-band model is constructed to reproduce the first-principles results. Our design, in addition, provides a general strategy to synthesize topologically nontrivial materials by virtue of organic chemistry and nanotechnology. PMID:23521279

  13. Flat Chern Band in a Two-Dimensional Organometallic Framework

    NASA Astrophysics Data System (ADS)

    Liu, Zheng; Wang, Zheng-Fei; Mei, Jia-Wei; Wu, Yong-Shi; Liu, Feng

    2013-03-01

    By combining exotic band dispersion with nontrivial band topology, an interesting type of band structure, namely, the flat Chern band, has recently been proposed to spawn high-temperature fractional quantum Hall states. Despite the proposal of several theoretical lattice models, however, it remains doubtful whether such a “romance of flatland” could exist in a real material. Here, we present a first-principles design of a two-dimensional indium-phenylene organometallic framework that realizes a nearly flat Chern band right around the Fermi level by combining lattice geometry, spin-orbit coupling, and ferromagnetism. An effective four-band model is constructed to reproduce the first-principles results. Our design, in addition, provides a general strategy to synthesize topologically nontrivial materials by virtue of organic chemistry and nanotechnology.

  14. Flat Chern Band in a Two-Dimensional Organometallic Framework

    NASA Astrophysics Data System (ADS)

    Liu, Zheng; Wang, Zheng-Fei; Mei, Jia-Wei; Wu, Yong-Shi; Liu, Feng

    2013-03-01

    By combining exotic band dispersion with nontrivial band topology, an interesting type of band, namely the flat chern band (FCB), has recently been proposed, in which carriers experience strong Coulomb interaction as well as topological frustration that in together spawn unprecedented topological strongly-correlated electronic states, such as high-temperature fractional quantum hall state. Despite the proposal of several theoretical lattice models, however, it remains a doubt whether such a ``romance of flatland'' could exist in a real material. Here, we present a first-principles design to realize a nearly FCB right around the Fermi level in a two-dimensional (2D) Indium-Phenylene Organometallic Framework (IPOF). Our design in addition provides a general strategy to synthesize topologically nontrivial materials in virtue of organic chemistry and nanotechnology. Supported by DOE-BES and ARL

  15. Electronic configurations and magnetic anisotropy in organometallic metallocenes

    SciTech Connect

    Nawa, Kenji Kitaoka, Yukie; Nakamura, Kohji; Akiyama, Toru; Ito, Tomonori

    2015-05-07

    Electronic configurations and magnetic anisotropy of organometallic metallocenes (MCp{sub 2}s) were investigated by means of first principles calculations based on the constraint density functional theory. The results predict that the ground states for M = Cr, Mn, Fe, Co, and Ni are the {sup 3}E{sub 2g}, {sup 2}E{sub 2g}, {sup 1}A{sub 1g}, {sup 2}E{sub 1g}, and {sup 3}A{sub 2g} states, respectively. The magnetizations of the CoCp{sub 2} and NiCp{sub 2} energetically favor highly orienting along the perpendicular and parallel directions to the cyclopentadienyl (Cp) plane, respectively, and the others show almost no preference for the magnetic easy axis.

  16. Outer-Sphere Electrophilic Fluorination of Organometallic Complexes.

    PubMed

    Milner, Lucy M; Pridmore, Natalie E; Whitwood, Adrian C; Lynam, Jason M; Slattery, John M

    2015-08-26

    Organofluorine chemistry plays a key role in materials science, pharmaceuticals, agrochemicals, and medical imaging. However, the formation of new carbon-fluorine bonds with controlled regiochemistry and functional group tolerance is synthetically challenging. The use of metal complexes to promote fluorination reactions is of great current interest, but even state-of-the-art approaches are limited in their substrate scope, often require activated substrates, or do not allow access to desirable functionality, such as alkenyl C(sp(2))-F or chiral C(sp(3))-F centers. Here, we report the formation of new alkenyl and alkyl C-F bonds in the coordination sphere of ruthenium via an unprecedented outer-sphere electrophilic fluorination mechanism. The organometallic species involved are derived from nonactivated substrates (pyridine and terminal alkynes), and C-F bond formation occurs with full regio- and diastereoselectivity. The fluorinated ligands that are formed are retained at the metal, which allows subsequent metal-mediated reactivity. PMID:26270894

  17. Reactivity of Gold Complexes towards Elementary Organometallic Reactions.

    PubMed

    Joost, Maximilian; Amgoune, Abderrahmane; Bourissou, Didier

    2015-12-01

    For a while, the reactivity of gold complexes was largely dominated by their Lewis acid behavior. In contrast to the other transition metals, the elementary steps of organometallic chemistry-oxidative addition, reductive elimination, transmetallation, migratory insertion-have scarcely been studied in the case of gold or even remained unprecedented until recently. However, within the last few years, the ability of gold complexes to undergo these fundamental reactions has been unambiguously demonstrated, and the reactivity of gold complexes was shown to extend well beyond π-activation. In this Review, the main achievements described in this area are presented in a historical context. Particular emphasis is set on mechanistic studies and structure determination of key intermediates. The electronic and structural parameters delineating the reactivity of gold complexes are discussed, as well as the remaining challenges. PMID:26768342

  18. Organometallic Rhenium Complexes Divert Doxorubicin to the Mitochondria.

    PubMed

    Imstepf, Sebastian; Pierroz, Vanessa; Rubbiani, Riccardo; Felber, Michael; Fox, Thomas; Gasser, Gilles; Alberto, Roger

    2016-02-18

    Doxorubicin, a well-established chemotherapeutic agent, is known to accumulate in the cell nucleus. By using ICP-MS, we show that the conjugation of two small organometallic rhenium complexes to this structural motif results in a significant redirection of the conjugates from the nucleus to the mitochondria. Despite this relocation, the two bioconjugates display excellent toxicity toward HeLa cells. In addition, we carried out a preliminarily investigation of aspects of cytotoxicity and present evidence that the conjugates disrupt the mitochondrial membrane potential, are strong inhibitors of human Topoisomerase II, and induce apoptosis. Such derivatives may enhance the therapeutic index of the aggressive parent drug and overcome drug resistance by influencing nuclear and mitochondrial homeostasis. PMID:26799241

  19. Effect of exposure in steam or argon on the creep properties of Ni-based alloys: Creep properties of Ni-based alloys

    SciTech Connect

    Dryepondt, S.; Unocic, K. A.; Pint, B. A.

    2012-09-17

    Although expensive, Ni-based superalloys are of interest for the ultrasupercritical steam program because of their good creep and oxidation resistance at temperature above 700 C. However, the effect of steam oxidation on the alloy mechanical properties is unknown, and creep specimens of alloy CCA617, 740 and 230 were pre-oxidized for 2000 and 4000h in steam at 800 C before testing in air at the same temperature. Exposure in steam decreased the creep properties of alloy CCA617 compared with as fabricated material, had less of an effect on alloy 740, and did not affect alloy 230. Testing of a specimen repolished after steam exposure as well as microstructure observation indicate that the oxidation affected zone at the specimen surface is not responsible for the properties degradation. Surprisingly, a similar time anneal in an inert environment resulted in a drastic decrease of creep rupture life and an increase in the creep rate and elongation at rupture. TEM analysis revealed that the mechanical properties decrease for alloy CCA617 is related to the absence of precipitates in the grain.

  20. Scalable Synthesis of Piperazines Enabled by Visible-Light Irradiation and Aluminum Organometallics

    PubMed Central

    Suárez-Pantiga, Samuel; Colas, Kilian; Johansson, Magnus J; Mendoza, Abraham

    2015-01-01

    The development of more active C–H oxidation catalysts has inspired a rapid, scalable, and stereoselective assembly of multifunctional piperazines through a [3+3] coupling of azomethine ylides. A combination of visible-light irradiation and aluminum organometallics is essential to promote this transformation, which introduces visible-light photochemistry of main-group organometallics and sets the basis for new and promising catalysts. PMID:26337253

  1. A synchrotron study of microstructure gradient in laser additively formed epitaxial Ni-based superalloy

    DOE PAGESBeta

    Xue, Jiawei; Zhang, Anfeng; Li, Yao; Qian, Dan; Wan, Jingchun; Qi, Baolu; Tamura, Nobumichi; Song, Zhongxiao; Chen, Kai

    2015-10-08

    Laser additive forming is considered to be one of the promising techniques to repair single crystal Ni-based superalloy parts to extend their life and reduce the cost. Preservation of the single crystalline nature and prevention of thermal mechanical failure are two of the most essential issues for the application of this technique. Here we employ synchrotron X-ray microdiffraction to evaluate the quality in terms of crystal orientation and defect distribution of a Ni-based superalloy DZ125L directly formed by a laser additive process rooted from a single crystalline substrate of the same material. We show that a disorientation gradient caused bymore » a high density of geometrically necessary dislocations and resultant subgrains exists in the interfacial region between the epitaxial and stray grains. This creates a potential relationship of stray grain formation and defect accumulation. In conclusion, the observation offers new directions on the study of performance control and reliability of the laser additive manufactured superalloys.« less

  2. Castability of Traditionally Wrought Ni-Based Superalloys for USC Steam Turbines

    SciTech Connect

    Jablonski, P D; Cowen, C J; Hawk, J A; Evens, N; Maziasz, P

    2011-02-27

    The high temperature components within conventional coal fired power plants are manufactured from ferritic/martensitic steels. In order to reduce greenhouse gas emissions the efficiency of pulverized coal steam power plants must be increased. The proposed steam temperature in the Advanced Ultra Supercritical (A-USC) power plant is high enough (760°C) that ferritic/martensitic steels will not work due to temperature limitations of this class of materials; thus Ni-based superalloys are being considered. The full size castings are quite substantial: ~4in thick, several feet in diameter and weigh 5-10,000lb each half. Experimental castings were quite a bit smaller, but section size was retained and cooling rate controlled in order to produce relevant microstructures. A multi-step homogenization heat treatment was developed in order to better deploy the alloy constituents. The castability of two traditionally wrought Ni-based superalloys to which minor alloy adjustments have been made in order to improve foundry performance is further explored.

  3. Effect of Microstructure on the High Temperature Fatigue Properties of Two Ni-based Superalloys

    SciTech Connect

    Muralidharan, Govindarajan; Battiste, Rick; Kenik, Edward A; Bentley, James; Bunting, Bruce G

    2010-01-01

    There is significant need for Ni-based superalloys in the next generation automotive engine components such as exhaust valves. High temperature, high cycle fatigue life is one of the important properties required for such applications. The focus of this work is to evaluate the effect of microstructure on the high cycle fatigue properties of two Ni-based alloys, alloy 751, an alloy used in these applications at lower temperatures, and Waspaloy. High cycle fatigue lives of the alloys at 870oC were evaluated using in-situ high temperature fully reversed fatigue tests at 870oC and a nominal frequency of 30 Hz. Scanning electron microscopy and transmission electron microscopy were used to characterize the microstructure of the alloys. Computational modeling was used to calculate the equilibrium microstructure and microstructural coarsening at 870oC. Correlation of fatigue properties with microstructure of the alloys shows that for the experimental conditions used in the study, the fatigue life of Waspaloy, which has greater high temperature strength and larger volume fraction, is better than that of alloy 751.

  4. A study of microstructural characteristics of Ni-based superalloys at high temperatures. Final Report

    SciTech Connect

    Lal, R.B.; Aggarwal, M.D.

    1990-12-01

    The microstructural characteristics of the Ni-based superalloy MAR-M245(Hf) which is used in manufacturing the components of the Space Shuttle main engine are studied. These superalloys need optimum heat treatment to get the best results. To find out the optimum heat treatment, the techniques of differential thermal analysis (DTA) and the optical photomicrographs were utilized. In the first phase, the existing experimental equipment like cutting, grinding/polishing machines and metallurgical microscope were set up to cut/polish and take the photomicrographs. In the beginning of the project a Perkin Elmer differential thermal analyzer DTA1700 along with a temperature programmed and the needed computer interface was procured and made operational. In the second year a Leitz Metallux-3 hot state research microscope was also procured and installed for in-situ observation of the superalloy samples. The hot stage when tested for the first time alloyed the thermocouple with the Tantalum heating element and has now been installed. Samples of MAR-M246(Hf), MAR-M247, Waspaloy, Udimet-41, CMSX-3, and CMSX-3 (Polycrystalline and single crystals) were studied using a differential thermal analyzer and the results are reported. Photomicrographs of the Ni-based superalloy MAR-M246 (Hf) were recorded before and after heat treatment at certain temperatures. More heat treatments need to be done before a final inference can be reached.

  5. A study of microstructural characteristics of Ni-based superalloys at high temperatures

    NASA Technical Reports Server (NTRS)

    Lal, Ravindra B.; Aggarwal, M. D.

    1990-01-01

    The microstructural characteristics of the Ni-based superalloy MAR-M245(Hf) which is used in manufacturing the components of the Space Shuttle main engine are studied. These superalloys need optimum heat treatment to get the best results. To find out the optimum heat treatment, the techniques of differential thermal analysis (DTA) and the optical photomicrographs were utilized. In the first phase, the existing experimental equipment like cutting, grinding/polishing machines and metallurgical microscope were set up to cut/polish and take the photomicrographs. In the beginning of the project a Perkin Elmer differential thermal analyzer DTA1700 along with a temperature programmed and the needed computer interface was procured and made operational. In the second year a Leitz Metallux-3 hot state research microscope was also procured and installed for in-situ observation of the superalloy samples. The hot stage when tested for the first time alloyed the thermocouple with the Tantalum heating element and has now been installed. Samples of MAR-M246(Hf), MAR-M247, Waspaloy, Udimet-41, CMSX-3, and CMSX-3 (Polycrystalline and single crystals) were studied using a differential thermal analyzer and the results are reported. Photomicrographs of the Ni-based superalloy MAR-M246 (Hf) were recorded before and after heat treatment at certain temperatures. More heat treatments need to be done before a final inference can be reached.

  6. The Estimation of Localized Corrosion Behavior of Ni-Based Dental Alloys Using Electrochemical Techniques

    NASA Astrophysics Data System (ADS)

    Mareci, Daniel; Chelariu, Romeu; Iacoban, Sorin; Munteanu, Corneliu; Bolat, Georgiana; Sutiman, Daniel

    2012-07-01

    The aim of this study is to investigate the electrochemical behavior of the five non-precious Ni-based dental casting alloys in acidified artificial saliva. For comparison, nickel was also investigated. In order to study the localized corrosion resistance, the cyclic potentiodynamic polarization (CCP) and electrochemical impedance spectroscopy were performed. Scanning electron microscopy (SEM) observations were made after the CCP tests. The Ni-Cr alloys with chromium (14-18%) contents were susceptible to localized corrosion. The Ni-Cr-Mo alloy with contents of chromium (≈13%) and molybdenum (9%) presents a dangerous breakdown, but have a zero corrosion potential so that the difference between them is around 650 mV. The Ni-Cr-Mo alloys with higher chromium (22-25%) and molybdenum (9-11%) contents had a much larger passive range in the polarization curve and were immune to pitting corrosion. Pitting resistance equivalent (PRE) of about ≈54 could provide the Ni-based alloy with a good pitting corrosion resistance.

  7. Origin of synergistic effect over Ni-based bimetallic surfaces: A density functional theory study

    NASA Astrophysics Data System (ADS)

    Fan, Chen; Zhu, Yi-An; Xu, Yue; Zhou, Yan; Zhou, Xing-Gui; Chen, De

    2012-07-01

    Density functional theory calculations have been conducted to explore the physical origin of the synergistic effect over Ni-based surface alloys using methane dissociation as a probe reaction. Some late transition metal atoms (M = Cu, Ru, Rh, Pd, Ag, Pt, and Au) are substituted for surface Ni atoms to examine the variation in electronic structure and adsorption property of Ni(111). Two types of threefold hollow sites, namely, the Ni2M and Ni3 sites, are taken into account. The calculated results indicate that the variation in the CHx adsorption energy at the Ni2M and Ni3 sites is dominated by the ensemble and ligand effect, respectively, and the other factors such as surface and adsorbate distortion and electrostatic interaction affect the catalytic properties of the bimetallic surfaces to a smaller extent. Both the Brønsted-Evans-Polanyi relationship and the scaling correlation hold true on the Ni-based bimetallic surfaces. With the combination of these two linear energy relations, the corrected binding energy of atomic C is found to be a good descriptor for representing the catalytic activity of the alloyed surfaces. Considering the compromise between the catalytic activity and catalyst stability, we suggest that the Rh/Ni catalyst is a good candidate for methane dissociation.

  8. Organometallic catalysts for primary phosphoric acid fuel cells

    NASA Technical Reports Server (NTRS)

    Walsh, Fraser

    1987-01-01

    A continuing effort by the U.S. Department of Energy to improve the competitiveness of the phosphoric acid fuel cell by improving cell performance and/or reducing cell cost is discussed. Cathode improvement, both in performance and cost, available through the use of a class of organometallic cathode catalysts, the tetraazaannulenes (TAAs), was investigated. A new mixed catalyst was identified which provides improved cathode performance without the need for the use of a noble metal. This mixed catalyst was tested under load for 1000 hr. in full cell at 160 to 200 C in phosphoric acid H3PO4, and was shown to provide stable performance. The mixed catalyst contains an organometallic to catalyze electroreduction of oxygen to hydrogen peroxide and a metal to catalyze further electroreduction of the hydrogen peroxide to water. Cathodes containing an exemplar mixed catalyst (e.g., Co bisphenyl TAA/Mn) operate at approximately 650 mV vs DHE in 160 C, 85% H3PO4 with oxygen as reactant. In developing this mixed catalyst, a broad spectrum of TAAs were prepared, tested in half-cell and in a rotating ring-disk electrode system. TAAs found to facilitate the production of hydrogen peroxide in electroreduction were shown to be preferred TAAs for use in the mixed catalyst. Manganese (Mn) was identified as a preferred metal because it is capable of catalyzing hydrogen peroxide electroreduction, is lower in cost and is of less strategic importance than platinum, the cathode catalyst normally used in the fuel cell.

  9. Organometallic catalysts for primary phosphoric acid fuel cells

    NASA Astrophysics Data System (ADS)

    Walsh, Fraser

    1987-03-01

    A continuing effort by the U.S. Department of Energy to improve the competitiveness of the phosphoric acid fuel cell by improving cell performance and/or reducing cell cost is discussed. Cathode improvement, both in performance and cost, available through the use of a class of organometallic cathode catalysts, the tetraazaannulenes (TAAs), was investigated. A new mixed catalyst was identified which provides improved cathode performance without the need for the use of a noble metal. This mixed catalyst was tested under load for 1000 hr. in full cell at 160 to 200 C in phosphoric acid H3PO4, and was shown to provide stable performance. The mixed catalyst contains an organometallic to catalyze electroreduction of oxygen to hydrogen peroxide and a metal to catalyze further electroreduction of the hydrogen peroxide to water. Cathodes containing an exemplar mixed catalyst (e.g., Co bisphenyl TAA/Mn) operate at approximately 650 mV vs DHE in 160 C, 85% H3PO4 with oxygen as reactant. In developing this mixed catalyst, a broad spectrum of TAAs were prepared, tested in half-cell and in a rotating ring-disk electrode system. TAAs found to facilitate the production of hydrogen peroxide in electroreduction were shown to be preferred TAAs for use in the mixed catalyst. Manganese (Mn) was identified as a preferred metal because it is capable of catalyzing hydrogen peroxide electroreduction, is lower in cost and is of less strategic importance than platinum, the cathode catalyst normally used in the fuel cell.

  10. Tribromobenzene on Cu(111): Temperature-dependent formation of halogen-bonded, organometallic, and covalent nanostructures

    SciTech Connect

    Fan, Qitang; Wang, Tao; Zhu, Junfa; Liu, Liming; Zhao, Jin; Gottfried, J. Michael

    2015-03-14

    The temperature-controlled surface-assisted synthesis of halogen bonded, organometallic, and covalent nanostructures based on 1,3,5-tribromo-benzene (TriBB) was studied with scanning tunneling microscopy and X-ray photoemission spectroscopy in ultrahigh vacuum. Vapor deposition of TriBB onto a Cu(111) surface held at 90 K leads to the formation of large domains of a honeycomb-like organic monolayer structure stabilized by triangular nodes with Br⋯Br intermolecular bonds. Upon annealing the organic monolayer to ∼140 K, a new hexagonal close-packed structure with intact TriBB molecules connected by Cu adatoms is formed. Further warming up the sample to 300 K gives rise to the scission of C–Br bonds and formation of C–Cu–C bonds between phenyl fragments such that stable dendritic organometallic networks are formed. Larger islands of organometallic networks are obtained by maintaining the temperature of Cu(111) at 420 K during deposition of TriBB. Simultaneously, large islands of Br atoms are formed around the organometallic networks. Annealing the more extended organometallic network (prepared at 420 K) to 520 K leads to the formation of a branched covalent organic framework (COF) which comprises structural elements of porous graphene and is surrounded by Br islands. These organometallic networks and COFs appear as small dendritic and branched domains, most likely due to the steric influence exerted by the Br islands.

  11. Tribromobenzene on Cu(111): Temperature-dependent formation of halogen-bonded, organometallic, and covalent nanostructures

    NASA Astrophysics Data System (ADS)

    Fan, Qitang; Wang, Tao; Liu, Liming; Zhao, Jin; Zhu, Junfa; Gottfried, J. Michael

    2015-03-01

    The temperature-controlled surface-assisted synthesis of halogen bonded, organometallic, and covalent nanostructures based on 1,3,5-tribromo-benzene (TriBB) was studied with scanning tunneling microscopy and X-ray photoemission spectroscopy in ultrahigh vacuum. Vapor deposition of TriBB onto a Cu(111) surface held at 90 K leads to the formation of large domains of a honeycomb-like organic monolayer structure stabilized by triangular nodes with Br⋯Br intermolecular bonds. Upon annealing the organic monolayer to ˜140 K, a new hexagonal close-packed structure with intact TriBB molecules connected by Cu adatoms is formed. Further warming up the sample to 300 K gives rise to the scission of C-Br bonds and formation of C-Cu-C bonds between phenyl fragments such that stable dendritic organometallic networks are formed. Larger islands of organometallic networks are obtained by maintaining the temperature of Cu(111) at 420 K during deposition of TriBB. Simultaneously, large islands of Br atoms are formed around the organometallic networks. Annealing the more extended organometallic network (prepared at 420 K) to 520 K leads to the formation of a branched covalent organic framework (COF) which comprises structural elements of porous graphene and is surrounded by Br islands. These organometallic networks and COFs appear as small dendritic and branched domains, most likely due to the steric influence exerted by the Br islands.

  12. Preliminary Investigations of Joining Technologies for Attaching Refractory Metals to Ni-Based Superalloys

    SciTech Connect

    Gould, Jerry E.; Ritzert, Frank J.; Loewenthal, William S.

    2006-01-20

    In this study, a range of joining technologies has been investigated for creating attachments between refractory metal and Ni-based superalloys. Refractory materials of interest include Mo-47%Re, T-111, and Ta-10%W. The Ni-based superalloys include Hastelloy X and MarM 247. During joining with conventional processes, these materials have potential for a range of solidification and intermetallic formation-related defects. For this study, three non-conventional joining technologies were evaluated. These included inertia welding, electro-spark deposition (ESD) welding, and magnetic pulse welding (MPW). The developed inertia welding practice closely paralleled that typically used for the refractory metals alloys. Metallographic investigations showed that forging during inertia welding occurred predominantly on the refractory metal side. It was also noted that at least some degree of forging on the Ni-based superalloy side of the joint was necessary to achieve consistent bonding. Both refractory metals were readily weldable to the Hastelloy X material. When bonding to the MarM 247, results were inconsistent. This was related to the higher forging temperatures of the MarM 247, and subsequent reduced deformation on that material during welding. ESD trials using a Hastelloy X filler were successful for all material combinations. ESD places down very thin (5- to 10-{mu}m) layers per pass, and interactions between the substrates and the fill were limited (at most) to that layer. For the refractory metals, the fill only appeared to wet the surface, with minimal dilution effects. Microstructures of the deposits showed high weld metal integrity with maximum porosity on the order of a few percent. Some limited success was also obtained with MPW. In these trials, only the T-111 tubes were used. Joints were possible for the T-111 tube to the Hastelloy X bar stock, but the stiffness of the tube (resisting collapse) necessitated the use of very high power levels. These power levels

  13. Performance of Alumina-Forming Austenitic Steels, Fe-base and Ni-base alloys exposed to metal dusting environments

    SciTech Connect

    Vande Put Ep Rouaix, Aurelie; Unocic, Kinga A; Pint, Bruce A; Brady, Michael P

    2011-01-01

    A series of conventional Fe- and Ni- base, chromia- and alumina- forming alloys, and a newly developed creep-resistant, alumina-forming austenitic steel were developed and its performance relative to conventional Fe- and Ni-based chromia-forming alloys was evaluated in metal dusting environments with a range of water vapor contents. Five 500h experiments have been performed at 650 C with different water vapor contents and total pressures. Without water vapor, the Ni-base alloys showed greater resistance to metal dusting than the Fe-base alloys, including AFA. However, with 10-28% water vapor, more protective behavior was observed with the higher-alloyed materials and only small mass changes were observed. Longer exposure times are in progress to further differentiate performance.

  14. Interdiffusion Behavior of Pt-Diffused gamma+gamma' Coatings on Ni-Based Superalloys

    SciTech Connect

    Zhang, Ying; Stacy, J P; Pint, Bruce A; Haynes, James A; Hazel, Brian T; Nagaraj, Ben

    2008-01-01

    Platinum-diffused {gamma} + {gamma}{prime} coatings ({approx} 20 at.% Al, {approx} 22 at.% Pt) were synthesized on Rene 142 and Rene N5 Ni-based superalloys by electroplating the substrates with {approx} 7 {micro}m of Pt, followed by an annealing treatment in vacuum at 1175 C. In order to study the compositional and microstructural evolution of these coatings at elevated temperatures, interdiffusion experiments were carried out on coated specimens in the temperature range of 900-1050 C for various durations. Composition profiles of the alloying elements in the {gamma} + {gamma}{prime} coatings before and after diffusion experiments were determined by electron probe microanalysis. Although the change of the Al content in the coatings was minimal under these interdiffusion conditions, the decrease of the Pt content and increase of the diffusion depth of Pt into the substrate alloys were significant. A preliminary diffusion model was used to estimate the Pt penetration depth after diffusion.

  15. Reduction of chromium in Ni-base superalloys through element substitution and rapid solidification processing

    NASA Technical Reports Server (NTRS)

    Fraser, H. D.; Muddl, B. C.

    1982-01-01

    The reduction in the use of Cr in Ni base superalloys by the combined approaches of both elemental substitution and rapid solidification processing is studied. The elements Si, Zr, Y and Hf were chosen as potential partial substitutes for Cr in Waspaloy and IN 713LC sine their separate addition to other alloys has previously resulted in enhanced oxidation resistance. The roles of Cr and these replacement elements in determining the microstructure and properties are evaluated. The elements Si, Zr, and Y and Hf are used as partial replacements for Cr in the base superalloys and these resultant alloys are processed using rapid solidification techniques. The mechanical properties and oxidation resistance of the processed materials are evaluated. The microstructure is characterized using state of the art techniques (e.g. analytical transmission electron microscopy), and the mechanism by which these structures are produced is determined.

  16. A ternary Ni-Al-W EAM potential for Ni-based single crystal superalloys

    NASA Astrophysics Data System (ADS)

    Fan, Qin-Na; Wang, Chong-Yu; Yu, Tao; Du, Jun-Ping

    2015-01-01

    Based on experiments and first-principles calculations, a ternary Ni-Al-W embedded-atom-method (EAM) potential is constructed for the Ni-based single crystal superalloys. The potential predicts that W atoms do not tend to form clusters in γ(Ni), which is consistent with experiments. The impurity diffusion of W in γ(Ni) is investigated using the five-frequency model. The diffusion coefficients and the diffusion activation energy of W are in reasonable agreement with the data in literatures. By W doping, the lattice misfit between the two phases decreases and the elastic constants of γ‧(Ni3Al) increase. As for alloyed elements Co, Re and W, the pinning effect of solute atom on the γ(Ni)/γ‧(Ni3Al) misfit dislocation increases with the increasing of the atomic radius.

  17. A study of microstructural characteristics and differential thermal analysis of Ni-based superalloys

    NASA Technical Reports Server (NTRS)

    Aggarwal, M. D.; Lal, R. B.; Oyekenu, Samuel A.; Parr, Richard; Gentz, Stephen

    1989-01-01

    The objective of this work is to correlate the mechanical properties of the Ni-based superalloy MAR M246(Hf) used in the Space Shuttle Main Engine with its structural characteristics by systematic study of optical photomicrographs and differential thermal analysis. The authors developed a method of predicting the liquidus and solidus temperature of various nickel based superalloys (MAR-M247, Waspaloy, Udimet-41, polycrystalline and single crystals of CMSX-2 and CMSX-3) and comparing the predictions with the experimental differential thermal analysis (DTA) curves using Perkin-Elmer DTA 1700. The method of predicting these temperatures is based on the additive effect of the components dissolved in nickel. The results were compared with the experimental values.

  18. Microstructural and Mechanical Properties of Ni-Base Thermal Spray Coatings Deposited by Flame Spraying

    NASA Astrophysics Data System (ADS)

    Amokrane, Bradai Mohand; Abdelhamid, Sadeddine; Youcef, Mouadji; Abderrahim, Benabbas; Nedjemeddine, Bounar; Ahmed, Mammeri

    2011-10-01

    In this work, two different Ni-base powders, namely, ProXon 21021 (P21) and ProXon 21031 (P31), were sprayed onto a steel substrate 35CrMo4 using a thermal flame spray technique. The morphology and chemical composition of the phases that are present in the powders and coatings were characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). The hardness and wear resistance of the coatings were investigated. The XRD analysis revealed that the phases present in the coatings are different from the initial powders. In addition, some inhomogeneities such as oxides, porosity, and unmelted particles were observed by SEM. It was found that the P31 spray-coated exhibited higher microhardness, higher wear resistance, and significantly lower friction coefficient in comparison with those of P21 coatings.

  19. A study of microstructural characteristics of Ni-based superalloys at high temperatures

    NASA Technical Reports Server (NTRS)

    Lal, R. B.; Aggarwal, M. D.

    1987-01-01

    The microstructure of the Ni-based superalloy MAR-M246 (Hf) which is used in manufacturing the components of the Space Shuttle Main Engine was investigated. In the first year, the superalloy will be studied using optical photomicrographs and the differential thermal analysis. During this period, the existing experimental equipment like cutting, grinding/polishing machines, metallurgical microscope will be used to but/polish and take the photomicrographs. At present, only a 35 mm camera attachment with the olympus inverted metallurgical microscope is being used. Due to this, there was considerable delay in processing photographs. A Perkin-Elmer Differential Thermal Analyzer (DTA-1700) was ordered and finally installed on April 28, 1987. Preliminary test runs were made on silver as well as MAR-M246 (Hf).

  20. Ni-base superalloy powder-processed porous layer for gas cooling in extreme environments

    DOE PAGESBeta

    White, Emma M. H.; Heidloff, Andrew J.; Byrd, David J.; Anderson, Ross D.; Anderson, Iver E.

    2016-05-26

    Extreme high temperature conditions demand novel solutions for hot gas filters and coolant access architectures, i.e., porous layers on exposed components. These high temperatures, for example in current turbine engines, are at or exceeding current material limits for high temperature oxidation/corrosion, creep resistance, and, even, melting temperature. Thus novel blade designs allowing greater heat removal are required to maintain airfoil temperatures below melting and/ or rapid creep deformation limits. Gas atomized Ni-base superalloy powders were partially sintered into porous layers to allow full-surface, transpirational cooling of the surface of airfoils. Furthermore, these powder-processed porous layers were fully characterized for surface,more » morphology, cross-sectional microstructure, and mechanical strength characteristics. A sintering model based on pure Ni surface diffusion correlated well with the experimental results and allowed reasonable control over the partial sintering process to obtain a specified level of porosity within the porous layer.« less

  1. Rapid solidification characteristics in melt spinning a Ni-base superalloy

    NASA Technical Reports Server (NTRS)

    Huang, S. C.; Laforce, R. P.; Ritter, A. M.; Goehner, R. P.

    1985-01-01

    The solidification kinetics involved in the process of melt spinning a Ni-base superalloy have been characterized. Through a correlation of ribbon thickness to melt puddle residence time, it was found that the solidification front velocity, V, is typically about 100 mm/sec at the ribbon surface not in contact with the spinning wheel. The rate of solidification varies within the ribbon, increasing with decreasing distance, S, from the wheel-contact surface as V = 3.65/s. Ribbon microstructure and texture characteristics are discussed in light of this kinetics result. The thickness-vs-time correlation was further analyzed to yield information about thermal history during ribbon formation. These thermal results are generally consistent with those deduced from dendrite arm spacing measurements.

  2. Modeling of Thermal Expansion Coefficients of Ni-Based Superalloys Using Artificial Neural Network

    NASA Astrophysics Data System (ADS)

    Bano, Nafisa; Nganbe, Michel

    2013-04-01

    The objective of this work is to model the thermal expansion coefficients of various Ni-based superalloys used in gas turbine components. The thermal expansion coefficient is described as a function of temperature, chemical composition including Ni, Cr, Co, Mo, W, Ta, Nb, Al, Ti, B, Zr, and C contents as well as heat treatment including solutionizing and aging. Experimental values are well described and their relative changes well correlated by the model. Because gas turbine engine components operate under severe loading conditions and at high and varying temperatures, the prediction of their thermal expansion coefficient is crucial. The model developed in this work can be useful for design optimizations for minimizing thermo-mechanical stresses between the base alloys and potential protective coatings or adjacent components. It can substantially contribute to improve the performance and service life of gas turbine components.

  3. Role of Elemental Sublimation during Solution Heat Treatment of Ni-Based Superalloys

    NASA Astrophysics Data System (ADS)

    D'Souza, N.; Simmonds, S.; West, G. D.; Dong, H. B.

    2013-10-01

    The role of elemental evaporation on the microstructural stability of blade surfaces has been investigated on solutioned and aged samples of Ni-based single-crystal superalloys. Evaporation of Ni and Cr at the casting surface during solution heat treatment leads to the formation of a Ni- and Cr-depleted layer at the surface. Nucleation and growth of γ' phase occur within this layer through subsequent long-range diffusion of Re, Ta, and W between the γ' layer and the substrate. Beyond a critical Ni and Cr loss, incipient melting initiates at the surface and principally γ' and TCP phases are stabilized with de-stabilization of γ phase. Nucleation of TCP phases occurs at grain boundaries arising from cellular recrystallization during the ramp-up cycle. Therefore, on quenching, a range of microstructures are observed at the casting surface.

  4. The effect of microstructure on the fatigue behavior of Ni base superalloys

    NASA Technical Reports Server (NTRS)

    Antolovich, S. D.; Jayaraman, N.

    1983-01-01

    Nickel-base superalloys are used in jet engine components such as disks, turbine blades, and vanes. Improvements in the fatigue behavior will allow the life to be extended or the payloads to be increased. The first part of the present investigation deals primarily with the effects of microstructural variations on the fatigue crack propagation (FCP) behavior of nickel-base alloys, while the second part is concerned with low-cycle fatigue (LCF) behavior of Ni base systems. Waspaloy at low temperature is considered, taking into account material heat treatment and test procedures, a composite plot of Waspaloy FCP data, Paris law fatigue crack propagation constants, monotonic tensile data, and overload FCP test results for Waspaloy. It is found that the FCP and overload behavior of nickel-base alloys may be markedly improved by heat treating. Attention is given to effects of cyclic deformation on microstructure and substructure, environmental damage, and an environmental/deformation model of high temperature LCF.

  5. Development of Ni-based Sulfur Resistant Catalyst for Diesel Reforming

    SciTech Connect

    Gunther Dieckmann

    2006-06-30

    In order for diesel fuel to be used in a solid oxide fuel cell auxiliary power unit, the diesel fuel must be reformed into hydrogen, carbon monoxide and carbon dioxide. One of the major problems facing catalytic reforming is that the level of sulfur found in low sulfur diesel can poison most catalysts. This report shows that a proprietary low cost Ni-based reforming catalyst can be used to reform a 7 and 50 ppm sulfur containing diesel fuel for over 500 hours of operation. Coking, which appears to be route of catalyst deactivation due to metal stripping, can be controlled by catalyst modifications, introduction of turbulence, and/or by application of an electromagnetic field with a frequency from {approx}50 kHz to 13.56 MHz with field strength greater than about 100 V/cm and more preferably greater about 500 V/cm.

  6. Analysis of WC/Ni-Based Coatings Deposited by Controlled Short-Circuit MIG Welding

    NASA Astrophysics Data System (ADS)

    Vespa, P.; Pinard, P. T.; Gauvin, R.; Brochu, M.

    2012-06-01

    This study investigates the recently developed controlled short-circuit metal inert gas (CSC-MIG) welding system for depositing WC/Ni-based claddings on carbon steel substrates. WC/Ni-based coatings deposited by CSC-MIG were analyzed by optical light microscopy and scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS) and electron backscatter diffraction (EBSD) capabilities. X-ray diffraction (XRD) and hardness measurements of depositions are also reported. The CSC-MIG welding system provides a significant amount of user control over the current waveform during welding and has lower heat input when compared with traditional MIG welding. Heat input for the analyzed coatings ranged from 10.1 to 108.7 J/mm. Metallurgically bonded coatings free from spatter and with 0.75% average porosity were produced. It was found that the detrimental decarburization of the WC particles seen in thermal spray systems does not occur when welding with the CSC-MIG. Precipitation of a reaction layer around the reinforcing phase was identified as WC; the average thickness of which increases from 3.8 to 7.2 μm for the low and high heat input condition, respectively. Precipitation of newly formed WC particles was observed; their size distribution increased from D 50 of 2.4 μm in the low heat input weldment to 6.75 μm in the high heat input weldment. The level of dilution of the reinforcing phase increases significantly with heat input. The hardness of the deposited coatings decreases from 587 HV10 to 410 HV10 when the energy input was increased from 10.1 to 108.7 J/mm.

  7. Microstructural characterization of a new mechanically alloyed Ni-base ODS superalloy powder

    SciTech Connect

    Seyyed Aghamiri, S.M.; Shahverdi, H.R.; Ukai, S.; Oono, N.; Taya, K.; Miura, S.; Hayashi, S.; Okuda, T.

    2015-02-15

    The microstructure of a new Ni-base oxide dispersion strengthened superalloy powder was studied for high temperature gas turbine applications after the mechanical alloying process. In this study, an atomized powder with a composition similar to the CMSX-10 superalloy was mechanically alloyed with yttria and Hf powders. The mechanically alloyed powder included only the supersaturated solid solution γ phase without γ′ and yttria provided by severe plastic deformation, while after the 3-step aging, the γ′ phase was precipitated due to the partitioning of Al and Ta to the γ′ and Co, Cr, Re, W, and Mo to the γ phase. Mechanical alloying modified the morphology of γ′ to the new coherent γ–γ′ nanoscale lamellar structure to minimize the elastic strain energy of the precipitation, which yielded a low lattice misfit of 0.16% at high temperature. The γ′ lamellae aligned preferentially along the elastically soft [100] direction. Also, the precipitated oxide particles were refined in the γ phase by adding Hf from large incoherent YAlO{sub 3} to fine semi-coherent Y{sub 2}Hf{sub 2}O{sub 7} oxide particles with the average size of 7 nm and low interparticle spacing of 76 nm. - Highlights: • A new Ni-base ODS superalloy powder was produced by mechanical alloying. • The nanoscale γ–γ′ lamellar structure was precipitated after the aging treatment. • Fine semi-coherent Y{sub 2}Hf{sub 2}O{sub 7} oxide particles were precipitated by addition of Hf.

  8. Generation, Characterization, and Tunable Reactivity of Organometallic Fragments Bound to a Protein Ligand.

    PubMed

    Key, Hanna M; Clark, Douglas S; Hartwig, John F

    2015-07-01

    Organotransition metal complexes catalyze important synthetic transformations, and the development of these systems has rested on the detailed understanding of the structures and elementary reactions of discrete organometallic complexes bound to organic ligands. One strategy for the creation of new organometallic systems is to exploit the intricate and highly structured ligands found in natural metalloproteins. We report the preparation and characterization of discrete rhodium and iridium fragments bound site-specifically in a κ(2)-fashion to the protein carbonic anhydrase as a ligand. The reactions of apo human carbonic anhydrase with [Rh(nbd)2]BF4 or [M(CO)2(acac)] (M=Rh, Ir) form proteins containing Rh or Ir with organometallic ligands. A colorimetric assay was developed to quantify rapidly the metal occupancy at the native metal-binding site, and (15)N-(1)H NMR spectroscopy was used to establish the amino acids to which the metal is bound. IR spectroscopy and EXAFS revealed the presence and number of carbonyl ligands and the number total ligands, while UV-vis spectroscopy provided a signature to readily identify species that had been fully characterized. Exploiting these methods, we observed fundamental stoichiometric reactions of the artificial organometallic site of this protein, including reactions that simultaneously form and cleave metal-carbon bonds. The preparation and reactivity of these artificial organometallic proteins demonstrate the potential to study a new genre of organometallic complexes for which the rates and outcomes of organometallic reactions can be controlled by genetic manipulation of the protein scaffold. PMID:26020584

  9. Understanding the electron-stimulated surface reactions of organometallic complexes to enable design of precursors for electron beam-induced deposition

    NASA Astrophysics Data System (ADS)

    Spencer, Julie A.; Rosenberg, Samantha G.; Barclay, Michael; Wu, Yung-Chien; McElwee-White, Lisa; Howard Fairbrother, D.

    2014-12-01

    Standard practice in electron beam-induced deposition (EBID) is to use precursors designed for thermal processes, such as chemical vapor deposition (CVD). However, organometallic precursors that yield pure metal deposits in CVD often create EBID deposits with high levels of organic contamination. This contamination negatively impacts the deposit's properties (e.g., by increasing resistivity or decreasing catalytic activity) and severely limits the range of potential applications for metal-containing EBID nanostructures. To provide the information needed for the rational design of precursors specifically for EBID, we have employed an ultra-high vacuum (UHV) surface science approach to identify the elementary reactions of organometallic precursors during EBID. These UHV studies have demonstrated that the initial electron-induced deposition of the surface-bound organometallic precursors proceeds through desorption of one or more of the ligands present in the parent compound. In specific cases, this deposition step has been shown to proceed via dissociative electron attachment, involving low-energy secondary electrons generated by the interaction of the primary beam with the substrate. Electron beam processing of the surface-bound species produced in the initial deposition event usually causes decomposition of the residual ligands, creating nonvolatile fragments. This process is believed to be responsible for a significant fraction of the organic contaminants typically observed in EBID nanostructures. A few ligands (e.g., halogens) can, however, desorb during electron beam processing while other ligands (e.g., PF3, CO) can thermally desorb if elevated substrate temperatures are used during deposition. Using these general guidelines for reactivity, we propose some design strategies for EBID precursors. The ultimate goal is to minimize organic contamination and thus overcome the key bottleneck for fabrication of relatively pure EBID nanostructures.

  10. New Molecular Architecture for Electrically Conducting Materials Based on Unsymmetrical Organometallic-Dithiolene Complexes

    NASA Astrophysics Data System (ADS)

    Kubo, Kazuya; Kato, Reizo

    New molecular architecture for highly conducting molecular materials was developed with use of unsymmetrical organometallic-dithiolene complexes. The new architecture has various advantages including easy modification of their molecular and electronic features. Organometallic complexes based on unsymmetrical Au(III)-dithiolene complexes [(ppy)Au(C8H4S8 or C8H4S6O2)] were prepared for new cationic components of molecular conductors. These unsymmetrical organometallic complexes can provide various cation radical salts [(ppy)Au(S-S)]2[anion][solvent] n (S-S = C8H4S8 or C8H4S6O2, anion = PF6 -, BF4 -, AsF6 -, TaF6 -, solvent = PhCl, n = 0-0.5) by constant current electrolysis of their benzonitrile or chlorobenzene solutions containing (Bu4N)(anion) as electrolyte. [(ppy)Au(C8H4S8)]2[PF6] under pressure is the first molecular metal based on the organometallic component. In this review, principle of the molecular architecture based on the unsymmetrical organometallic-dithiolene complexes and physical properties of their cation radical salts are discussed.

  11. Switching on Elusive Organometallic Mechanisms with Photoredox Catalysis

    PubMed Central

    Terrett, Jack A.; Cuthbertson, James D.; Shurtleff, Valerie W.; MacMillan, David W. C.

    2015-01-01

    Transition metal-catalyzed cross-coupling reactions have become one of the most utilized carbon–carbon and carbon–heteroatom bond-forming reactions in chemical synthesis. More recently, nickel catalysis has been shown to participate in a wide variety of C–C bond forming reactions, most notably Negishi, Suzuki–Miyaura, Stille, Kumada, and Hiyama couplings1,2. Despite the tremendous advances in C–C fragment couplings, the ability to forge C–O bonds in a general fashion via nickel catalysis has been largely unsuccessful. The challenge for nickel-mediated alcohol couplings has been the mechanistic requirement for the critical C–O bond forming step (formally known as the reductive elimination step) to occur via a Ni(III) alkoxide intermediate. In this manuscript, we demonstrate that visible light-excited photoredox catalysts can modulate the preferred oxidation states of nickel alkoxides in an operative catalytic cycle, thereby providing transient access to Ni(III) species that readily participate in reductive elimination. Using this synergistic merger of photoredox and nickel catalysis, we have developed a highly efficient and general carbon–oxygen coupling reaction using abundant alcohols and aryl bromides. More significantly, we have developed a general strategy to “switch on” important yet elusive organometallic mechanisms via oxidation state modulations using only weak light and single-electron transfer (SET) catalysts. PMID:26266976

  12. Switching on elusive organometallic mechanisms with photoredox catalysis.

    PubMed

    Terrett, Jack A; Cuthbertson, James D; Shurtleff, Valerie W; MacMillan, David W C

    2015-08-20

    Transition-metal-catalysed cross-coupling reactions have become one of the most used carbon-carbon and carbon-heteroatom bond-forming reactions in chemical synthesis. Recently, nickel catalysis has been shown to participate in a wide variety of C-C bond-forming reactions, most notably Negishi, Suzuki-Miyaura, Stille, Kumada and Hiyama couplings. Despite the tremendous advances in C-C fragment couplings, the ability to forge C-O bonds in a general fashion via nickel catalysis has been largely unsuccessful. The challenge for nickel-mediated alcohol couplings has been the mechanistic requirement for the critical C-O bond-forming step (formally known as the reductive elimination step) to occur via a Ni(III) alkoxide intermediate. Here we demonstrate that visible-light-excited photoredox catalysts can modulate the preferred oxidation states of nickel alkoxides in an operative catalytic cycle, thereby providing transient access to Ni(III) species that readily participate in reductive elimination. Using this synergistic merger of photoredox and nickel catalysis, we have developed a highly efficient and general carbon-oxygen coupling reaction using abundant alcohols and aryl bromides. More notably, we have developed a general strategy to 'switch on' important yet elusive organometallic mechanisms via oxidation state modulations using only weak light and single-electron-transfer catalysts. PMID:26266976

  13. Deciphering Halogen Competition in Organometallic Halide Perovskite Growth

    DOE PAGESBeta

    Keum, Jong Kahk; Ovchinnikova, Olga S.; Chen, Shiyou; Du, Mao-Hua; Ivanov, Ilia N; Rouleau, Christopher; Geohegan, David B.; Xiao, Kai

    2016-03-01

    Organometallic halide perovskites (OHPs) hold great promise for next-generation, low-cost optoelectronic devices. During the chemical synthesis and crystallization of OHP thin films a major unresolved question is the competition between multiple halide species (e.g. I-, Cl-, Br-) in the formation of the mixed halide perovskite crystals. Whether Cl- ions are successfully incorporated into the perovskite crystal structure or alternatively, where they are located, is not yet fully understood. Here, in situ X-ray diffraction measurements of crystallization dynamics are combined with ex situ TOF-SIMS chemical analysis to reveal that Br- or Cl- ions can promote crystal growth, yet reactive I- ionsmore » prevent them from incorporating into the lattice of the final perovskite crystal structure. The Cl- ions are located in the grain boundaries of the perovskite films. These findings significantly advance our understanding of the role of halogens during synthesis of hybrid perovskites, and provide an insightful guidance to the engineering of high-quality perovskite films, essential for exploring superior-performance and cost-effective optoelectronic devices.« less

  14. Synthesis and properties of novel, electroactive organometallic polymers

    SciTech Connect

    Not Available

    1987-01-01

    The object of this research is to synthesize a number of organometallic polymers based on 1,8-dimetallocenylnaphthalene (1) as a monomeric structural unit, and to examine the physical properties of these substances, especially their electrical conductance. In such polymers contiguous metallocene units are held face-to-face in a columnar array, so that conduction, in the partially oxidized material can in principal be achieved through {pi}-orbital interaction of neighboring metallocene units. The author has shown that low molecular weight polymers, based on 1 (M=Fe or Ru) can be prepared by palladium catalyzed coupling of ferrocenylzinc halides with 1,8-diiodonaphthalene, and now propose to define reaction conditions for the preparation of much higher molecular weight polymers. The synthesis of analogous polymers incorporating cobalt and nickel, through the use of cobaltocene and nickelocene in the coupling reaction, will also be examined. Other mixed metal polymeric systems, in which two transition metals alternate along the chain, may be preparable from 1,8-bis(cyclopentadienyl)naphthalene 3, recently synthesized in our laboratories. The preparation of 3 should also provide and opportunity for the synthesis of unique polymeric systems based on linear dimeric, trigonal trimeric and tetrahedral tetrameric cyclopentadienylmetal complexes. These syntheses will be examined. Finally, the application of the coupling-polymerization reaction to 1,4-dihalobenzenes will also be examined. 34 refs., 3 figs.

  15. Deciphering Halogen Competition in Organometallic Halide Perovskite Growth.

    PubMed

    Yang, Bin; Keum, Jong; Ovchinnikova, Olga S; Belianinov, Alex; Chen, Shiyou; Du, Mao-Hua; Ivanov, Ilia N; Rouleau, Christopher M; Geohegan, David B; Xiao, Kai

    2016-04-20

    Organometallic halide perovskites (OHPs) hold great promise for next-generation, low-cost optoelectronic devices. During the chemical synthesis and crystallization of OHP thin films, a major unresolved question is the competition between multiple halide species (e.g., I(-), Cl(-), Br(-)) in the formation of the mixed-halide perovskite crystals. Whether Cl(-) ions are successfully incorporated into the perovskite crystal structure or, alternatively, where they are located is not yet fully understood. Here, in situ X-ray diffraction measurements of crystallization dynamics are combined with ex situ TOF-SIMS chemical analysis to reveal that Br(-) or Cl(-) ions can promote crystal growth, yet reactive I(-) ions prevent them from incorporating into the lattice of the final perovskite crystal structure. The Cl(-) ions are located in the grain boundaries of the perovskite films. These findings significantly advance our understanding of the role of halogens during synthesis of hybrid perovskites and provide an insightful guidance to the engineering of high-quality perovskite films, essential for exploring superior-performing and cost-effective optoelectronic devices. PMID:26931634

  16. Coordination of dibensothiophenes and corannulenes to organometallic ruthenium (II) fragments

    SciTech Connect

    Vecchi, Paul Anthony

    2005-05-01

    This dissertation contains five papers in the format required for journal publication which describe (in part) my research accomplishments as a graduate student at Iowa State University. This work can be broadly categorized as the binding of weakly-coordinating ligands to cationic organometallic ruthenium fragments, and consists of two main areas of study. Chapters 2-4 are investigations into factors that influence the binding of dibenzothiophenes to {l_brace}Cp'Ru(CO){sub 2}{r_brace}{sup +} fragments, where Cp' = {eta}{sup 5}-C{sub 5}H{sub 5} (Cp) and {eta}{sup 5}-C{sub 5}Me{sub 5} (Cp*). Chapters 5 and 6 present the synthesis and structural characterization of complexes containing corannulene buckybowls that are {eta}{sup 6}-coordinated to {l_brace}Cp*Ru{r_brace}{sup +} fragments. The first chapter contains a brief description of the difficulty in lowering sulfur levels in diesel fuel along with a review of corannulene derivatives and their metal complexes. After the final paper is a short summary of the work herein (Chapter 7). Each chapter is independent, and all equations, schemes, figures, tables, references, and appendices in this dissertation pertain only to the chapter in which they appear.

  17. Degradation of organometallic perovskite solar cells induced by trap states

    NASA Astrophysics Data System (ADS)

    Song, Dandan; Ji, Jun; Li, Yaoyao; Li, Guanying; Li, Meicheng; Wang, Tianyue; Wei, Dong; Cui, Peng; He, Yue; Mbengue, Joseph Michel

    2016-02-01

    The degradation of organometallic perovskite solar cells (PSCs) is the key bottleneck hampering their development, which is typically ascribed to the decomposition of perovskite (CH3NH3PbI3). In this work, the degradation of PSCs is observed to be significant, with the decrease in efficiency from 18.2% to 11.5% in ambient air for 7 days. However, no obvious decomposition or structural evolution of the perovskite was observed, except the notable degradation phenomenon of the device. The degradation of PSCs derives from deteriorated photocurrent and fill factor, which are proven to be induced by increased trap states for enlarged carrier recombination in degraded PSCs. The increased trap states in PSCs over storage time are probably induced by the increased defects at the surface of perovskite. The trap states induced degradation provides a physical insight into the degradation mechanisms of PSCs. Moreover, as the investigations were performed on real PSCs instead of individual perovskite films, the findings here present one of their actual degradation mechanisms.

  18. Record Multiphoton Absorption Cross-Sections by Dendrimer Organometalation.

    PubMed

    Simpson, Peter V; Watson, Laurance A; Barlow, Adam; Wang, Genmiao; Cifuentes, Marie P; Humphrey, Mark G

    2016-02-12

    Large increases in molecular two-photon absorption, the onset of measurable molecular three-photon absorption, and record molecular four-photon absorption in organic π-delocalizable frameworks are achieved by incorporation of bis(diphosphine)ruthenium units with alkynyl linkages. The resultant ruthenium alkynyl-containing dendrimers exhibit strong multiphoton absorption activity through the biological and telecommunications windows in the near-infrared region. The ligated ruthenium units significantly enhance solubility and introduce fully reversible redox switchability to the optical properties. Increasing the ruthenium content leads to substantial increases in multiphoton absorption properties without any loss of optical transparency. This significant improvement in multiphoton absorption performance by incorporation of the organometallic units into the organic π-framework is maintained when the relevant parameters are scaled by molecular weights or number of delocalizable π-electrons. The four-photon absorption cross-section of the most metal-rich dendrimer is an order of magnitude greater than the previous record value. PMID:26797727

  19. Switching on elusive organometallic mechanisms with photoredox catalysis

    NASA Astrophysics Data System (ADS)

    Terrett, Jack A.; Cuthbertson, James D.; Shurtleff, Valerie W.; MacMillan, David W. C.

    2015-08-01

    Transition-metal-catalysed cross-coupling reactions have become one of the most used carbon-carbon and carbon-heteroatom bond-forming reactions in chemical synthesis. Recently, nickel catalysis has been shown to participate in a wide variety of C-C bond-forming reactions, most notably Negishi, Suzuki-Miyaura, Stille, Kumada and Hiyama couplings. Despite the tremendous advances in C-C fragment couplings, the ability to forge C-O bonds in a general fashion via nickel catalysis has been largely unsuccessful. The challenge for nickel-mediated alcohol couplings has been the mechanistic requirement for the critical C-O bond-forming step (formally known as the reductive elimination step) to occur via a Ni(III) alkoxide intermediate. Here we demonstrate that visible-light-excited photoredox catalysts can modulate the preferred oxidation states of nickel alkoxides in an operative catalytic cycle, thereby providing transient access to Ni(III) species that readily participate in reductive elimination. Using this synergistic merger of photoredox and nickel catalysis, we have developed a highly efficient and general carbon-oxygen coupling reaction using abundant alcohols and aryl bromides. More notably, we have developed a general strategy to `switch on' important yet elusive organometallic mechanisms via oxidation state modulations using only weak light and single-electron-transfer catalysts.

  20. Investigation on corrosion behavior of Ni-based alloys in molten fluoride salt using synchrotron radiation techniques

    NASA Astrophysics Data System (ADS)

    Liu, Min; Zheng, Junyi; Lu, Yanling; Li, Zhijun; Zou, Yang; Yu, Xiaohan; Zhou, Xingtai

    2013-09-01

    Ni-based alloys have been selected as the structural materials in molten-salt reactors due to their high corrosion resistance and excellent mechanical properties. In this paper, the corrosion behavior of some Ni-based superalloys including Inconel 600, Hastelloy X and Hastelloy C-276 were investigated in molten fluoride salts at 750 °C. Morphology and microstructure of corroded samples were analyzed using scanning electron microscope (SEM), synchrotron radiation X-ray microbeam fluorescence (μ-XRF) and synchrotron radiation X-ray diffraction (SR-XRD) techniques. Results from μ-XRF and SR-XRD show that the main depleted alloying element of Ni-based alloys in molten fluoride salt is Cr. In addition, the results indicate that Mo can enhance the corrosion resistance in molten FLiNaK salts. Among the above three Ni-based alloys, Hastelloy C-276 exhibits the best corrosion resistance in molten fluoride salts 750 °C. Higher-content Mo and lower-content Cr in Hastelloy C-276 alloy were responsible for the better anti-corrosive performance, compared to the other two alloys.

  1. Study of the HVOF Ni-Based Coatings' Corrosion Resistance Applied on Municipal Solid-Waste Incinerators

    NASA Astrophysics Data System (ADS)

    Guilemany, J. M.; Torrell, M.; Miguel, J. R.

    2008-06-01

    Oxidation of exchanger steel tubes causes important problems in Municipal Solid-Waste Incinerator (MSWI) plants. The present paper shows a possible solution for this problem through High-Velocity Oxygen Fuel (HVOF) thermal spray coatings. A comparative study was carried out between powder and wire Ni-based thermal spray coatings (with the same composition). These optimized coatings were compared based on their microstructure, wear properties (ASTM G99-90, ASTM G65-91), and erosion-corrosion (E-C) resistance. An E-C test designed in the Thermal Spray Centre was performed to reproduce the mechanisms that take place in a boiler. Studying the results of this test, the wire HVT Inconel coating sprayed by propylene appears to be the best alternative. A commercial bulk material with a composition similar to Ni-based coatings was tested to find the products of the oxidation reactions. The protective mechanisms of these materials were assessed after studying the results obtained for HVOF coatings and the bulk material where the presence of nickel and chromium oxides as a corrosion product can be seen. Kinetic evolution of the Ni-based coatings can be studied by thermogravimetric analysis. The protection that Inconel coatings give to the tube through the difference of the gain mass can be seen. Ni-based HVOF coatings by both spray conditions are a promising alternative to MSWI protection against chlorine environments, and their structures have a very important role.

  2. Superior reactivity of skeletal Ni-based catalysts for low-temperature steam reforming to produce CO-free hydrogen.

    PubMed

    Zhang, Chengxi; Zhang, Peng; Li, Shuirong; Wu, Gaowei; Ma, Xinbin; Gong, Jinlong

    2012-03-14

    This paper describes the utilization of skeletal Ni-based catalysts for steam reforming of ethanol to produce CO-free hydrogen, which could be superior in the application of fuel cells. Assistant metals play different roles in the reaction; Pt and Cu suppress the methanation and enhance H(2) production, while Co promotes the methanation. PMID:22297434

  3. Combining Organometallic Reagents, the Sulfur Dioxide Surrogate DABSO, and Amines: A One-Pot Preparation of Sulfonamides, Amenable to Array Synthesis**

    PubMed Central

    Deeming, Alex S; Russell, Claire J; Willis, Michael C

    2015-01-01

    We describe a method for the synthesis of sulfonamides through the combination of an organometallic reagent, a sulfur dioxide equivalent, and an aqueous solution of an amine under oxidative conditions (bleach). This simple reaction protocol avoids the need to employ sulfonyl chloride substrates, thus removing the limitation imposed by the commercial availability of these reagents. The resultant method allows access to new chemical space, and is also tolerant of the polar functional groups needed to impart favorable physiochemical properties required for medicinal chemistry and agrochemistry. The developed chemistry is employed in the synthesis of a targeted 70 compound array, prepared using automated methods. The array achieved a 93 % success rate for compounds prepared. Calculated molecular weights, lipophilicities, and polar surface areas are presented, demonstrating the utility of the method for delivering sulfonamides with drug-like properties. PMID:25431118

  4. Combining organometallic reagents, the sulfur dioxide surrogate DABSO, and amines: a one-pot preparation of sulfonamides, amenable to array synthesis.

    PubMed

    Deeming, Alex S; Russell, Claire J; Willis, Michael C

    2015-01-19

    We describe a method for the synthesis of sulfonamides through the combination of an organometallic reagent, a sulfur dioxide equivalent, and an aqueous solution of an amine under oxidative conditions (bleach). This simple reaction protocol avoids the need to employ sulfonyl chloride substrates, thus removing the limitation imposed by the commercial availability of these reagents. The resultant method allows access to new chemical space, and is also tolerant of the polar functional groups needed to impart favorable physiochemical properties required for medicinal chemistry and agrochemistry. The developed chemistry is employed in the synthesis of a targeted 70 compound array, prepared using automated methods. The array achieved a 93% success rate for compounds prepared. Calculated molecular weights, lipophilicities, and polar surface areas are presented, demonstrating the utility of the method for delivering sulfonamides with drug-like properties. PMID:25431118

  5. Organometallic Palladium Complexes with a Water-Soluble Iminophosphorane Ligand as Potential Anticancer Agents

    PubMed Central

    Carreira, Monica; Calvo-Sanjuán, Rubén; Sanaú, Mercedes; Marzo, Isabel; Contel, María

    2012-01-01

    The synthesis and characterization of a new water-soluble iminophosphorane ligand TPA=N-C(O)-2BrC6H4 (C,N-IM; TPA = 1,3,5-triaza-7-phosphaadamantane) 1 is reported. Oxidative addition of 1 to Pd2(dba)3 affords the orthopalladated dimer [Pd(μ-Br){C6H4(C(O)N=TPA-kC,N)-2}]2 (2) as a mixture of cis and trans isomers (1:1 molar ratio) where the iminophosphorane moeity behaves as a C,N-pincer ligand. By addition of different neutral or monoanionic ligands to 2, the bridging bromide can be cleaved and a variety of hydrophilic or water-soluble mononuclear organometallic palladium(II) complexes of the type [Pd{C6H4(C(O)N=TPA-kC,N)-2}(L-L)] (L-L = acac (3); S2CNMe2 (4); 4,7-Diphenyl-1,10-phenanthrolinedisulfonic acid disodium salt C12H6N2(C6H4SO3Na)2 (5)); [Pd{C6H4(C(O)N=TPA-kC,N)-2}(L)Br] (L = P(mC6H4SO3Na)3 (6); P(3-Pyridyl)3 (7)) and, [Pd(C6H4(C(O)N=TPA)-2}(TPA)2Br] (8) are obtained as single isomers. All new complexes were tested as potential anticancer agents and their cytotoxicity properties were evaluated in vitro against human Jurkat-T acute lymphoblastic leukemia cells, normal T-lymphocytes (PBMC) and DU-145 human prostate cancer cells. Compounds [Pd(μ-Br){C6H4(C(O)N=TPA-kC,N)-2}]2 (2) and [Pd{C6H4(C(O)N=TPA-kC,N)-2}(acac)] 3 (which has been crystallographically characterized) display the higher cytotoxicity against the above mentioned cancer cell lines while being less toxic to normal T-lymphocytes (peripheral blood mononuclear cells: PBMC). In addition, 3 is very toxic to cisplatin resistant Jurkat shBak indicating a cell death pathway that may be different to that of cisplatin. The interaction of 2 and 3 with plasmid (pBR322) DNA is much weaker than that of cisplatin pointing to an alternative biomolecular target for these cytotoxic compounds. All the compounds show an interaction with human serum albumin (HSA) faster than that of cisplatin. PMID:23066172

  6. [Development of new synthetic method using organometallic complexes and an application toward natural product synthesis].

    PubMed

    Mori, Miwako

    2005-01-01

    Recently, many organometallic complexes, such as palladium, nickel, ruthenium, titanium complexes and others, were used for synthetic organic chemistry. We have developed many novel synthetic methods using these organometallic complexes for synthetic organic chemistry. As the organometallic complexes, nickel, chromium, molybdenum, ruthenium, zirconium, titanium, and palladium complexes, were used. Furthermore, bimetallic complexes having silicon-tin and silicon-zirconium bonds were investigated. On the other hand, utilization of gases in synthetic organic chemistry has been also developed. 1 atm pressure of gases such as CO, CO(2), N(2), ethylene and acetylene, could be used and the reaction procedure is very simple, that a balloon filled with a gas is connected on the top of the flask. Using our novel synthetic methods, we have synthesized many natural products and biologically active substances, such as cephalotaxin, mesembrine, tubifoline, strychnine, stemoamide, lycopodine, pumiliotoxin C, beta-lactam, carbapenam and benzodiazepinone derivatives. PMID:15635281

  7. Preliminary Investigations of Joining Technologies for Attaching Refractory Metals to Ni-Based Superalloys

    NASA Technical Reports Server (NTRS)

    Gould, Jerry E.; Ritzert, Frank J.; Loewenthal, William S.

    2006-01-01

    In this study, a range of joining technologies has been investigated for creating attachments between refractory metal and Ni-based superalloys. Refractory materials of interest include Mo-47%Re, T-111, and Ta-10%W. The Ni-based superalloys include Hastelloy X and MarM 247. During joining with conventional processes, these materials have potential for a range of solidification and intermetallic formation-related defects. For this study, three non-conventional joining technologies were evaluated. These included inertia welding, electro-spark deposition (ESD) welding, and magnetic pulse welding (MPW). The developed inertia welding practice closely paralleled that typically used for the refractory metals alloys. Metallographic investigations showed that forging during inertia welding occurred predominantly on the nickel base alloy side. It was also noted that at least some degree of forging on the refractory metal side of the joint was necessary to achieve consistent bonding. Both refractory metals were readily weldable to the Hastelloy X material. When bonding to the MarM 247, results were inconsistent. This was related to the higher forging temperatures of the MarM 247, and subsequent reduced deformation on that material during welding. ESD trials using a Hastelloy X filler were successful for all material combinations. ESD places down very thin (5- to 10- m) layers per pass, and interactions between the substrates and the fill were limited (at most) to that layer. For the refractory metals, the fill only appeared to wet the surface, with minimal dilution effects. Microstructures of the deposits showed high weld metal integrity with maximum porosity on the order of a few percent. Some limited success was also obtained with MPW. In these trials, only the T-111 tubes were used. Joints were possible for the T-111 tube to the Hastelloy X bar stock, but the stiffness of the tube (resisting collapse) necessitated the use of very high power levels. These power levels

  8. The direct synthesis of organic and organometallic-containing MICA-type aluminosilicates

    SciTech Connect

    Carrado, K.A.; Awaluddin, A.

    1993-08-01

    Layer-silicate clay structures can provide supramolecular organization for catalysis, chiral reactions, colloid science, and electron transfer. The authors have successfully modified the experimental preparations of several different layer silicates in order to incorporate a wide variety of organic and organometallic molecules in the clay galleries. Synthesis and physical characterization of these materials are described and compared to ion-exchanged natural clay analogs. In addition, the photophysical properties of organometallic Ru(II) complexes incorporated by direct hydrothermal crystallization into synthetic clays were measured. 3 tabs, 21 refs.

  9. Bimodal X-ray and Infrared Imaging of an Organometallic Derivative of Praziquantel in Schistosoma mansoni.

    PubMed

    Clède, Sylvain; Cowan, Noemi; Lambert, François; Bertrand, Hélène C; Rubbiani, Riccardo; Patra, Malay; Hess, Jeannine; Sandt, Christophe; Trcera, Nicolas; Gasser, Gilles; Keiser, Jennifer; Policar, Clotilde

    2016-06-01

    An organometallic derivative of praziquantel was studied directly in worms by using inductively coupled plasma-mass spectrometry (ICP-MS) for quantification and synchrotron-based imaging. X-ray fluorescence (XRF) and IR absorption spectromicroscopy were used for the first time in combination to directly locate this organometallic drug candidate in schistosomes. The detection of both CO (IR) and Cr (XRF) signatures proved that the Cr(CO)3 core remained intact in the worms. Images showed a preferential accumulation at the worm's tegument, consistent with a possible targeting of the calcium channel but not excluding other biological targets inside the worm. PMID:26991635

  10. Theoretical evidence of photo-induced charge transfer from DNA to intercalated ruthenium (II) organometallic complexes

    NASA Astrophysics Data System (ADS)

    Chantzis, Agisilaos; Very, Thibaut; Daniel, Chantal; Monari, Antonio; Assfeld, Xavier

    2013-07-01

    The absorption spectrum of two ruthenium (II) organometallic complexes intercalated into DNA is studied at the quantum mechanic/molecular mechanic level. The macromolecular environment is taken into account as to include geometric, electrostatic and polarization effects that can alter the excitation energy and oscillator strength. The inclusion of DNA base pairs into the quantum mechanic partition allows us for the first time to clearly evidence the presence of charge transfer excited states involving an electron withdraw from DNA base pairs to the organometallic complex.

  11. Molecular metal catalysts on supports: organometallic chemistry meets surface science.

    PubMed

    Serna, Pedro; Gates, Bruce C

    2014-08-19

    Recent advances in the synthesis and characterization of small, essentially molecular metal complexes and metal clusters on support surfaces have brought new insights to catalysis and point the way to systematic catalyst design. We summarize recent work unraveling effects of key design variables of site-isolated catalysts: the metal, metal nuclearity, support, and other ligands on the metals, also considering catalysts with separate, complementary functions on supports. The catalysts were synthesized with the goal of structural simplicity and uniformity to facilitate incisive characterization. Thus, they are essentially molecular species bonded to porous supports chosen for their high degree of uniformity; the supports are crystalline aluminosilicates (zeolites) and MgO. The catalytic species are synthesized in reactions of organometallic precursors with the support surfaces; the precursors include M(L)2(acetylacetonate)1-2, with M = Ru, Rh, Ir, or Au and the ligands L = C2H4, CO, or CH3. Os3(CO)12 and Ir4(CO)12 are used as precursors of supported metal clusters, and some such catalysts are made by ship-in-a-bottle syntheses to trap the clusters in zeolite cages. The simplicity and uniformity of the supported catalysts facilitate precise structure determinations, even in reactive atmospheres and during catalysis. The methods of characterizing catalysts in reactive atmospheres include infrared (IR), extended X-ray absorption fine structure (EXAFS), X-ray absorption near edge structure (XANES), and nuclear magnetic resonance (NMR) spectroscopies, and complementary methods include density functional theory and atomic-resolution aberration-corrected scanning transmission electron microscopy for imaging of individual metal atoms. IR, NMR, XANES, and microscopy data demonstrate the high degrees of uniformity of well-prepared supported species. The characterizations determine the compositions of surface metal complexes and clusters, including the ligands and the metal

  12. Synthesis and evaluation of new polynuclear organometallic Ru(II), Rh(III) and Ir(III) pyridyl ester complexes as in vitro antiparasitic and antitumor agents.

    PubMed

    Chellan, Prinessa; Land, Kirkwood M; Shokar, Ajit; Au, Aaron; An, Seung Hwan; Taylor, Dale; Smith, Peter J; Riedel, Tina; Dyson, Paul J; Chibale, Kelly; Smith, Gregory S

    2014-01-14

    New polynuclear organometallic Platinum Group Metal (PGM) complexes containing di- and tripyridyl ester ligands have been synthesised and characterised using analytical and spectroscopic techniques including (1)H, (13)C NMR and infrared spectroscopy. Reaction of these polypyridyl ester ligands with either [Ru(p-cymene)Cl2]2, [Rh(C5Me5)Cl2]2 or [Ir(C5Me5)Cl2]2 dimers yielded the corresponding di- or trinuclear organometallic complexes. The polyaromatic ester ligands act as monodentate donors to each metal centre and this coordination mode was confirmed upon elucidation of the molecular structures for two of the dinuclear complexes. The di- and trinuclear PGM complexes synthesized were evaluated for inhibitory effects on the human protozoal parasites Plasmodium falciparum strain NF54 (chloroquine sensitive), Trichomonas vaginalis strain G3 and the human ovarian cancer cell lines, A2780 (cisplatin-sensitive) and A2780cisR (cisplatin-resistant) cell lines. All of the complexes were observed to have moderate to high antiplasmodial activities and the compounds with the best activities were evaluated for their ability to inhibit formation of synthetic hemozoin in a cell free medium. The in vitro antitumor evaluation of these complexes revealed that the trinuclear pyridyl ester complexes demonstrated moderate activities against the two tumor cell lines and were also less toxic to model non-tumorous cells. PMID:24121555

  13. Atom probe tomography of Ni-base superalloys Allvac 718Plus and Alloy 718.

    PubMed

    Viskari, L; Stiller, K

    2011-05-01

    Atom probe tomography (APT) allows near atomic scale compositional- and morphological studies of, e.g. matrix, precipitates and interfaces in a wide range of materials. In this work two Ni-base superalloys with similar compositions, Alloy 718 and its derivative Allvac 718Plus, are subject for investigation with special emphasis on the latter alloy. The structural and chemical nuances of these alloys are important for their properties. Of special interest are grain boundaries as their structure and chemistry are important for the materials' ability to resist rapid environmentally induced crack propagation. APT has proved to be suitable for analyses of these types of alloys using voltage pulsed APT. However, for investigations of specimens containing grain boundaries and other interfaces the risk for early specimen fracture is high. Analyses using laser pulsing impose lower electrical field on the specimen thereby significantly increasing the success rate of investigations. Here, the effect of laser pulsing was studied and the derived appropriate acquisition parameters were then applied for microstructural studies, from which initial results are shown. Furthermore, the influence of the higher evaporation field experienced by the hardening γ' Ni(3)(Al,Nb) precipitates on the obtained results is discussed. PMID:21295914

  14. Hot Deformation Processing Map and Microstructural Evaluation of the Ni-Based Superalloy IN-738LC

    NASA Astrophysics Data System (ADS)

    Sajjadi, S. A.; Chaichi, A.; Ezatpour, H. R.; Maghsoudlou, A.; Kalaie, M. A.

    2016-04-01

    Hot deformation behavior of the Ni-based superalloy IN-738LC was investigated by means of hot compression tests over the temperature range of 1000-1200 °C and strain rate range of 0.01-1 s-1. The obtained peak flow stresses were related to strain rate and temperature through the hyperbolic sine equation with activation energy of 950 kJ/mol. Dynamic material model was used to obtain the processing map of IN-738LC. Analysis of the microstructure was carried out in order to study each domain's characteristic represented by the processing map. The results showed that dynamic recrystallization occurs in the temperature range of 1150-1200 °C and strain rate of 0.1 s-1 with the maximum power dissipation efficiency of 35%. The unstable domain was exhibited in the temperature range of 1000-1200 °C and strain rate of 1 s-1 on the occurrence of severe deformation bands and grain boundary cracking.

  15. Control of Interfacial Reactivity Between ZrB2 and Ni-Based Brazing Alloys

    NASA Astrophysics Data System (ADS)

    Valenza, F.; Muolo, M. L.; Passerone, A.; Cacciamani, G.; Artini, C.

    2012-05-01

    Transition metals diborides (Ti,Zr,Hf)B2 play a key role in applications where stability at extremely high temperatures and damage tolerance are required; however, much research has still to be done to optimize the joining of these materials to themselves or to other high-temperature materials. In this study, the reactivity at the solid-liquid interface between ZrB2 ceramics and Ni-based brazing alloys has been addressed; it is shown how the reactivity and the dissolution of the solid phase can be controlled and even suppressed by adjusting the brazing alloy composition on the basis of thermodynamic calculations. Wetting experiments on ZrB2 ceramics by Ni, Ni-B 17 at.%, and Ni-B 50 at.% were performed at 1500 and 1200 °C by the sessile drop technique. The obtained interfaces were characterized by optical microscopy and SEM-EDS, and interpreted by means of the ad hoc-calculated B-Ni-Zr ternary diagram. A correlation among microstructures, substrate dissolution, shape of the drops, spreading kinetics, and the phase diagram was found. The effect on the interfacial reactivity of Si3Ni4 used as a sintering aid and issues related to Si diffusion into the brazing alloy are discussed as well.

  16. Kinetics and Mechanisms of γ′ Reprecipitation in a Ni-based Superalloy

    PubMed Central

    Masoumi, F.; Shahriari, D.; Jahazi, M.; Cormier, J.; Devaux, A.

    2016-01-01

    The reprecipitation mechanisms and kinetics of γ′ particles during cooling from supersolvus and subsolvus temperatures were studied in AD730TM Ni-based superalloy using Differential Thermal Analysis (DTA). The evolution in the morphology and distribution of reprecipitated γ′ particles was investigated using Field Emission Gun Scanning Electron Microscopy (FEG-SEM). Depending on the cooling rate, γ′ particles showed multi or monomodal distribution. The irregularity growth characteristics observed at lower cooling rates were analyzed in the context of Mullins and Sekerka theory, and allowed the determination of a critical size of γ′ particles above which morphological instability appears. Precipitation kinetics parameters were determined using a non-isothermal JMA model and DTA data. The Avrami exponent was determined to be in the 1.5–2.3 range, suggesting spherical or irregular growth. A methodology was developed to take into account the temperature dependence of the rate coefficient k(T) in the non-isothermal JMA equation. In that regard, a function for k(T) was developed. Based on the results obtained, reprecipitation kinetics models for low and high cooling rates are proposed to quantify and predict the volume fraction of reprecipitated γ′ particles during the cooling process. PMID:27338868

  17. First-principles study of magnetic properties of Fe-Ni based alloys

    NASA Astrophysics Data System (ADS)

    Onoue, M.; Trimarchi, G.; Freeman, A. J.

    2013-03-01

    Investigations of the magnetic properties of Fe-Ni based alloys are important from the fundamental as well as technological points of view. Furthermore, the magnetization at saturation and Curie temperature (TC) of FeNi can be tuned for specific applications by alloying with other metallic species. We have performed electronic structure calculations on Fe-Ni- M alloys, where M are 3d transition metals, to determine how the magnetization depends on the species M and alloy composition. Electronic band structure and total energies are calculated by the Korringa-Kohn-Rostoker method within the coherent-potential-approximation (KKR-CPA). For the KKR-CPA calculations, we use the generalized gradient approximation of the exchange and correlation functional. In the case of Fe0.50Ni0.45M0 . 05 (M=Sc, Ti, V, Cr, Mn, and Co), the early 3 d atoms have antiparallel magnetic moments to the Fe or Ni, whereas the late ones, Mn and Co, have a parallel magnetic moment. Supported by the NU-Boeing Alliance

  18. Electron phonon coupling in Ni-based binary alloys with application to displacement cascade modeling

    DOE PAGESBeta

    Samolyuk, German D.; Stocks, George Malcolm; Stoller, Roger E.

    2016-04-01

    Energy transfer between lattice atoms and electrons is an important channel of energy dissipation during displacement cascade evolution in irradiated materials. On the assumption of small atomic displacements, the intensity of this transfer is controlled by the strength of electron–phonon (el–ph) coupling. The el–ph coupling in concentrated Ni-based alloys was calculated using electronic structure results obtained within the coherent potential approximation. It was found that Ni0.5Fe0.5, Ni0.5Co0.5 and Ni0.5Pd0.5 are ordered ferromagnetically, whereas Ni0.5Cr0.5 is nonmagnetic. Since the magnetism in these alloys has a Stoner-type origin, the magnetic ordering is accompanied by a decrease of electronic density of states atmore » the Fermi level, which in turn reduces the el–ph coupling. Thus, the el–ph coupling values for all alloys are approximately 50% smaller in the magnetic state than for the same alloy in a nonmagnetic state. As the temperature increases, the calculated coupling initially increases. After passing the Curie temperature, the coupling decreases. The rate of decrease is controlled by the shape of the density of states above the Fermi level. Introducing a two-temperature model based on these parameters in 10 keV molecular dynamics cascade simulation increases defect production by 10–20% in the alloys under consideration.« less

  19. Influence of coarsened and rafted microstructures on the thermomechanical fatigue of a Ni-base superalloy

    DOE PAGESBeta

    Kirka, M. M.; Brindley, K. A.; Neu, R. W.; Antolovich, S. D.; Shinde, S. R.; Gravett, P. W.

    2015-08-17

    The aging of the microstructure of Ni-base superalloys during service is mainly characterized by coarsening and rafting of the γ' precipitates. The influence of these different aged microstructures on thermomechanical fatigue (TMF) under either continuously cycled (CC) and creep-fatigue (CF) was investigated. Three different aged microstructures, generated through accelerated aging and pre-creep treatments, were studied: stress-free coarsened γ', rafted with orientation perpendicular to loading direction (N-raft), and rafted with orientation parallel to loading direction (P-raft). Under most conditions, the aged microstructures were less resistant to TMF than the virgin microstructure; however, there were exceptions. Both stress-free coarsened and N-raft microstructuresmore » resulted in a reduction in TMF life under both CC and CF conditions in comparison to the virgin material. P-raft microstructure also resulted in reduction in TMF life under CC conditions; however, an increase in life over that of the virgin material was observed under CF conditions. Finally, these differences are discussed and hypothesized to be related to the interactions of the dislocations in the γ channels with γ' precipitates.« less

  20. Unexpected δ-Phase Formation in Additive-Manufactured Ni-Based Superalloy

    NASA Astrophysics Data System (ADS)

    Idell, Y.; Levine, L. E.; Allen, A. J.; Zhang, F.; Campbell, C. E.; Olson, G. B.; Gong, J.; Snyder, D. R.; Deutchman, H. Z.

    2016-03-01

    An as-built and solutionized Ni-based superalloy built by additive manufacturing through a direct metal laser sintering technique is characterized to understand the microstructural differences as compared to the as-wrought alloy. Initially, each layer undergoes rapid solidification as it is melted by the laser; however, as the part is built, the underlying layers experience a variety of heating and cooling cycles that produce significant microsegregation of niobium which allows for the formation of the deleterious δ-phase. The as-built microstructure was characterized through Vickers hardness, optical microscopy, scanning and transmission electron microscopy, electron back-scattering diffraction, x-ray diffraction, and synchrotron x-ray microLaue diffraction. The isothermal formation and growth of the δ-phase were characterized using synchrotron-based in situ small angle and wide angle x-ray scattering experiments. These experimental results are compared with multicomponent diffusion simulations that predict the phase fraction and composition. The high residual stresses and unexpected formation of the δ-phase will require further annealing treatments to be designed so as to remove these deficiencies and obtain an optimized microstructure.

  1. Study of microstructural characteristics of Ni-based superalloys at high temperatures. Semiannual technical report

    SciTech Connect

    Lal, R.B.; Aggarwal, M.D.

    1988-11-01

    The microstructural characteristics of the Ni-based superalloy MAR-M246(Hf) which is used in manufacturing the components of the Space Shuttle's main engine have been studied. These superalloys need optimal heat treatment to get the best results. To find the optimum heat treatment the technique of differential thermal analysis and the optical photomicrographs are being planned to be utilized. In the first phase, the existing experimental equipment like cutting, grinding/polishing machines and metallurgical microscope have been set up to cut/polish and take the photomicrographs. In the beginning of this year an order was placed for the Leitz Mettalux-3 microscope with a hot stage for in-situ observation of the superalloy samples. The hot stage was tested for the first time, alloying the thermocouple with the Tantulum heating element and has not been installed finally by the supplier. A Perkin Elmer Differential Thermal Analyzer (DTA 1700) was procured in the first year of the project. Samples of MAR-M246(Hf), MAR-M247, Waspaloy, Udimet-41, CMSX-2 and CMSX-3 (polycrystalline and single crystals) have been studied using differential thermal analyzer.

  2. Burner Rig Hot Corrosion of Five Ni-Base Alloys Including Mar-M247

    NASA Technical Reports Server (NTRS)

    Nesbitt, James A.; Helmink, R.; Harris, K.; Erickson, G.

    2000-01-01

    The hot corrosion resistance of four new Ni-base superalloys was compared to that of Mar-M247 by testing in a Mach 0.3 burner rig at 900 C for 300 1-hr cycles. While the Al content was held the same as in the Mar-M247, the Cr and Co levels in the four new alloys were decreased while other strengthening elements (Re, Ta) were increased. Surprisingly, despite their lower Cr and Co contents, the hot corrosion behavior of all four new alloys was superior to that of the Mar-M247 alloy. The Mar-M247 alloy began to lose weight almost immediately whereas the other four alloys appeared to undergo an incubation period of 50-150 1-hr cycles. Examination of the cross-sectional microstructures showed regions of rampant corrosion attack (propagation stage) in all five alloys after 300 1-hr cycles . This rampant corrosion morphology was similar for each of the alloys with Ni and Cr sulfides located in an inner subscale region. The morphology of the attack suggests a classic "Type I", or high temperature, hot corrosion attack.

  3. Carbon Deposition Onto Ni-Based Catalysts for Combined Steam/CO2 Reforming of Methane.

    PubMed

    Li, Peng; Park, Yoon Hwa; Moon, Dong Ju; Park, Nam Cook; Kim, Young Chul

    2016-02-01

    The present study was performed to suppress carbon deposition by Ce and Fe onto Ni-based catalysts in combined steam/CO2 reforming of methane (CSCRM), which is a process for producing synthesis gas (H2:CO = 2:1) for gas-to-liquids (GTL). The catalytic reaction was evaluated at 900 degrees C and 20 bar with a reactant feed ratio CH4:CO2:H20:Ar = 1:0.8:1.3:1 and gas hourly space velocity GHSV = 25,000 h(-1). The Ce and Fe modified Ni/gamma-A120, catalyst was characterized by BET surface area analysis, X-ray diffraction (XRD), H2 temperature-programmed reduction (TPR), H2 chemisorption, CO2 temperature-programmed desorption (TPD) and SEM. Ce- and Fe-modified Ni/Al2O3 catalysts exhibited remarkable activity and stability during the CSCRM over the course of 50 hours. It suggested that the Ni(12)-Ce(5)-Fe(5)/Al2O3 catalyst shows highly dispersed Ni particles with strong metal-to-support interaction (SMSI) as well as excellent catalytic activity. PMID:27433622

  4. Development of Ni-based multilayers for future focusing soft gamma ray telescopes

    NASA Astrophysics Data System (ADS)

    Girou, David A.; Massahi, Sonny; Sleire, Erlend K.; Jakobsen, Anders C.; Christensen, Finn E.

    2015-09-01

    Ni-based multilayers are a possible solution to extend the upper energy range of hard X-ray focusing telescopes currently limited at ≈79:4 keV by the Pt-K absorption edge. In this study 10 bilayers multilayers with a constant bilayer thickness were coated with the DC magnetron sputtering facility at DTU Space, characterized at 8 keV using X-ray reectometry and fitted using the IMD software. Ni/C multilayers were found to have a mean interface roughness ≈ 1:5 times lower than Ni/B4C multilayers. Reactive sputtering with ≈ 76% of Ar and ≈ 24% of N2 reduced the mean interface roughness by a factor of ≈ 1:7. It also increased the coating rate of C by a factor of ≈ 3:1 and lead to a coating process going ≈ 1:6 times faster. Honeycomb collimation proved to limit the increase in mean interface roughness when the bilayer thickness increases at the price of a coating process going ≈ 1:9 times longer than with separator plates. Finally a Ni/C 150 bilayers depth-graded mutilayer was coated with reactive sputtering and honeycomb collimation and then characterized from 10 keV to 150 keV. It showed 10% reectance up to 85 keV.

  5. Wear Characteristics of Ni-Based Hardfacing Alloy Deposited on Stainless Steel Substrate by Laser Cladding

    NASA Astrophysics Data System (ADS)

    Awasthi, Reena; Limaye, P. K.; Kumar, Santosh; Kushwaha, Ram P.; Viswanadham, C. S.; Srivastava, Dinesh; Soni, N. L.; Patel, R. J.; Dey, G. K.

    2015-03-01

    In this study, dry sliding wear characteristics of the Ni-based hardfacing alloy (Ni-Mo-Cr-Si) deposited on stainless steel SS316L substrate by laser cladding have been presented. Dry sliding wear behavior of the laser clad layer was evaluated against two different counter bodies, AISI 52100 chromium steel (~850 VHN) and tungsten carbide ball (~2200 VHN) to study both adhesive and abrasive wear characteristics, in comparison with the substrate SS316L using ball on plate reciprocating wear tester. The wear resistance was evaluated as a function of load and sliding speed for a constant sliding amplitude and sliding distance. The wear mechanisms were studied on the basis of wear surface morphology and microchemical analysis of the wear track using SEM-EDS. Laser clad layer of Ni-Mo-Cr-Si on SS316L exhibited much higher hardness (~700 VHN) than that of substrate SS316L (~200 VHN). The laser clad layer exhibited higher wear resistance as compared to SS316L substrate while sliding against both the counterparts. However, the improvement in the wear resistance of the clad layer as compared to the substrate was much higher while sliding against AISI 52100 chromium steel than that while sliding against WC, at the same contact stress intensity.

  6. Electron–phonon coupling in Ni-based binary alloys with application to displacement cascade modeling

    NASA Astrophysics Data System (ADS)

    Samolyuk, G. D.; Béland, L. K.; Stocks, G. M.; Stoller, R. E.

    2016-05-01

    Energy transfer between lattice atoms and electrons is an important channel of energy dissipation during displacement cascade evolution in irradiated materials. On the assumption of small atomic displacements, the intensity of this transfer is controlled by the strength of electron–phonon (el–ph) coupling. The el–ph coupling in concentrated Ni-based alloys was calculated using electronic structure results obtained within the coherent potential approximation. It was found that Ni0.5Fe0.5, Ni0.5Co0.5 and Ni0.5Pd0.5 are ordered ferromagnetically, whereas Ni0.5Cr0.5 is nonmagnetic. Since the magnetism in these alloys has a Stoner-type origin, the magnetic ordering is accompanied by a decrease of electronic density of states at the Fermi level, which in turn reduces the el–ph coupling. Thus, the el–ph coupling values for all alloys are approximately 50% smaller in the magnetic state than for the same alloy in a nonmagnetic state. As the temperature increases, the calculated coupling initially increases. After passing the Curie temperature, the coupling decreases. The rate of decrease is controlled by the shape of the density of states above the Fermi level. Introducing a two-temperature model based on these parameters in 10 keV molecular dynamics cascade simulation increases defect production by 10–20% in the alloys under consideration.

  7. Mechanically alloyed Ni-base alloys for heat-resistant applications

    SciTech Connect

    Wilson, R.K.; Fischer, J.J.

    1995-12-31

    INCONEL alloys MA 754 and MA 758 are nickel-base oxide dispersion-strengthened (ODS) alloys made by mechanical alloying (MA). Commercial use of Ma Ni-base alloys to date has been predominantly in aerospace applications of alloy MA 754 as turbine engine vanes. Both alloys are suitable for industrial heat treating components and other heat resistant alloy applications. Field trials and commercial experience in such applications of MA alloys are being gained while high temperature property characterization and new product form development continue. Hot isostatic pressing (HIP) is the standard consolidation method for billets from which large bar and plate are produced for industrial applications of MA. This paper describes production of standard mill shapes from HIP billets, and it presents information on current and potential uses of MA alloys in applications such as: skid rails for use in high temperature walking beam furnaces, heat treating furnace components, components for handling molten glass, and furnace tubes. The paper includes comparison of the properties obtained in alloy MA 754 (20% Cr) and alloy MA 758 (30% Cr).

  8. Atomic-scale properties of Ni-based FCC ternary, and quaternary alloys

    SciTech Connect

    Tamm, Artur; Aabloo, Alvo; Klintenberg, Mattias; Stocks, Malcolm; Caro, Alfredo

    2015-08-26

    The aim of our study is to characterize some atomic-scale properties of Ni-based FCC multicomponent alloys. For this purpose, we use Monte Carlo method combined with density functional theory calculations to study short-range order (SRO), atomic displacements, electronic density of states, and magnetic moments in equimolar ternary NiCrCo, and quaternary NiCrCoFe alloys. The salient features for the ternary alloy are a negative SRO parameter between Ni Cr and a positive between Cr Cr pairs as well as a weakly magnetic state. For the quaternary alloy we predict negative SRO parameter for Ni Cr and Ni Fe pairs and positive for Cr Cr and Fe Fe pairs. Atomic displacements for both ternary and quaternary alloys are negligible. In contrast to the ternary, the quaternary alloy shows a complex magnetic structure. The electronic structure of the ternary and quaternary alloys shows differences near the Fermi energy between a random solid solution and the predicted structure with SRO. Despite that, the calculated EXAFS spectra does not show enough contrast to discriminate between random and ordered structures. Finally, the predicted SRO has an impact on point-defect energetics, electron phonon coupling and thermodynamic functions and thus, SRO should not be neglected when studying properties of these two alloys.

  9. Electron-phonon coupling in Ni-based binary alloys with application to displacement cascade modeling.

    PubMed

    Samolyuk, G D; Béland, L K; Stocks, G M; Stoller, R E

    2016-05-01

    Energy transfer between lattice atoms and electrons is an important channel of energy dissipation during displacement cascade evolution in irradiated materials. On the assumption of small atomic displacements, the intensity of this transfer is controlled by the strength of electron-phonon (el-ph) coupling. The el-ph coupling in concentrated Ni-based alloys was calculated using electronic structure results obtained within the coherent potential approximation. It was found that Ni0.5Fe0.5, Ni0.5Co0.5 and Ni0.5Pd0.5 are ordered ferromagnetically, whereas Ni0.5Cr0.5 is nonmagnetic. Since the magnetism in these alloys has a Stoner-type origin, the magnetic ordering is accompanied by a decrease of electronic density of states at the Fermi level, which in turn reduces the el-ph coupling. Thus, the el-ph coupling values for all alloys are approximately 50% smaller in the magnetic state than for the same alloy in a nonmagnetic state. As the temperature increases, the calculated coupling initially increases. After passing the Curie temperature, the coupling decreases. The rate of decrease is controlled by the shape of the density of states above the Fermi level. Introducing a two-temperature model based on these parameters in 10 keV molecular dynamics cascade simulation increases defect production by 10-20% in the alloys under consideration. PMID:27033732

  10. Sample-Size Effects on the Compression Behavior of a Ni-BASED Amorphous Alloy

    NASA Astrophysics Data System (ADS)

    Liang, Weizhong; Zhao, Guogang; Wu, Linzhi; Yu, Hongjun; Li, Ming; Zhang, Lin

    Ni42Cu5Ti20Zr21.5Al8Si3.5 bulk metallic glasses rods with diameters of 1 mm and 3 mm, were prepared by arc melting of composing elements in a Ti-gettered argon atmosphere. The compressive deformation and fracture behavior of the amorphous alloy samples with different size were investigated by testing machine and scanning electron microscope. The compressive stress-strain curves of 1 mm and 3 mm samples exhibited 4.5% and 0% plastic strain, while the compressive fracture strength for 1 mm and 3 mm rod is 4691 MPa and 2631 MPa, respectively. The compressive fracture surface of different size sample consisted of shear zone and non-shear one. Typical vein patterns with some melting drops can be seen on the shear region of 1 mm rod, while fish-bone shape patterns can be observed on 3 mm specimen surface. Some interesting different spacing periodic ripples existed on the non-shear zone of 1 and 3 mm rods. On the side surface of 1 mm sample, high density of shear bands was observed. The skip of shear bands can be seen on 1 mm sample surface. The mechanisms of the effect of sample size on fracture strength and plasticity of the Ni-based amorphous alloy are discussed.

  11. Kinetics and Mechanisms of γ‧ Reprecipitation in a Ni-based Superalloy

    NASA Astrophysics Data System (ADS)

    Masoumi, F.; Shahriari, D.; Jahazi, M.; Cormier, J.; Devaux, A.

    2016-06-01

    The reprecipitation mechanisms and kinetics of γ‧ particles during cooling from supersolvus and subsolvus temperatures were studied in AD730TM Ni-based superalloy using Differential Thermal Analysis (DTA). The evolution in the morphology and distribution of reprecipitated γ‧ particles was investigated using Field Emission Gun Scanning Electron Microscopy (FEG-SEM). Depending on the cooling rate, γ‧ particles showed multi or monomodal distribution. The irregularity growth characteristics observed at lower cooling rates were analyzed in the context of Mullins and Sekerka theory, and allowed the determination of a critical size of γ‧ particles above which morphological instability appears. Precipitation kinetics parameters were determined using a non-isothermal JMA model and DTA data. The Avrami exponent was determined to be in the 1.5–2.3 range, suggesting spherical or irregular growth. A methodology was developed to take into account the temperature dependence of the rate coefficient k(T) in the non-isothermal JMA equation. In that regard, a function for k(T) was developed. Based on the results obtained, reprecipitation kinetics models for low and high cooling rates are proposed to quantify and predict the volume fraction of reprecipitated γ‧ particles during the cooling process.

  12. Kinetics and Mechanisms of γ' Reprecipitation in a Ni-based Superalloy.

    PubMed

    Masoumi, F; Shahriari, D; Jahazi, M; Cormier, J; Devaux, A

    2016-01-01

    The reprecipitation mechanisms and kinetics of γ' particles during cooling from supersolvus and subsolvus temperatures were studied in AD730(TM) Ni-based superalloy using Differential Thermal Analysis (DTA). The evolution in the morphology and distribution of reprecipitated γ' particles was investigated using Field Emission Gun Scanning Electron Microscopy (FEG-SEM). Depending on the cooling rate, γ' particles showed multi or monomodal distribution. The irregularity growth characteristics observed at lower cooling rates were analyzed in the context of Mullins and Sekerka theory, and allowed the determination of a critical size of γ' particles above which morphological instability appears. Precipitation kinetics parameters were determined using a non-isothermal JMA model and DTA data. The Avrami exponent was determined to be in the 1.5-2.3 range, suggesting spherical or irregular growth. A methodology was developed to take into account the temperature dependence of the rate coefficient k(T) in the non-isothermal JMA equation. In that regard, a function for k(T) was developed. Based on the results obtained, reprecipitation kinetics models for low and high cooling rates are proposed to quantify and predict the volume fraction of reprecipitated γ' particles during the cooling process. PMID:27338868

  13. A study of microstructural characteristics of Ni-based superalloys at high temperatures

    NASA Technical Reports Server (NTRS)

    Lal, R. B.; Aggarwal, M. D.

    1988-01-01

    The microstructural characteristics of the Ni-based superalloy MAR-M246(Hf) which is used in manufacturing the components of the Space Shuttle's main engine have been studied. These superalloys need optimal heat treatment to get the best results. To find the optimum heat treatment the technique of differential thermal analysis and the optical photomicrographs are being planned to be utilized. In the first phase, the existing experimental equipment like cutting, grinding/polishing machines and metallurgical microscope have been set up to cut/polish and take the photomicrographs. In the beginning of this year an order was placed for the Leitz Mettalux-3 microscope with a hot stage for in-situ observation of the superalloy samples. The hot stage was tested for the first time, alloying the thermocouple with the Tantulum heating element and has not been installed finally by the supplier. A Perkin Elmer Differential Thermal Analyzer (DTA 1700) was procured in the first year of the project. Samples of MAR-M246(Hf), MAR-M247, Waspaloy, Udimet-41, CMSX-2 and CMSX-3 (polycrystalline and single crystals) have been studied using differential thermal analyzer.

  14. Influence of coarsened and rafted microstructures on the thermomechanical fatigue of a Ni-base superalloy

    SciTech Connect

    Kirka, M. M.; Brindley, K. A.; Neu, R. W.; Antolovich, S. D.; Shinde, S. R.; Gravett, P. W.

    2015-08-17

    The aging of the microstructure of Ni-base superalloys during service is mainly characterized by coarsening and rafting of the γ' precipitates. The influence of these different aged microstructures on thermomechanical fatigue (TMF) under either continuously cycled (CC) and creep-fatigue (CF) was investigated. Three different aged microstructures, generated through accelerated aging and pre-creep treatments, were studied: stress-free coarsened γ', rafted with orientation perpendicular to loading direction (N-raft), and rafted with orientation parallel to loading direction (P-raft). Under most conditions, the aged microstructures were less resistant to TMF than the virgin microstructure; however, there were exceptions. Both stress-free coarsened and N-raft microstructures resulted in a reduction in TMF life under both CC and CF conditions in comparison to the virgin material. P-raft microstructure also resulted in reduction in TMF life under CC conditions; however, an increase in life over that of the virgin material was observed under CF conditions. Finally, these differences are discussed and hypothesized to be related to the interactions of the dislocations in the γ channels with γ' precipitates.

  15. Development of Microstructural Damage in Ni-Based Alloys During Creep

    NASA Astrophysics Data System (ADS)

    Yonemura, Mitsuharu; Semba, Hiroyuki; Igarashi, Masaaki

    2016-04-01

    Ni-based model alloys with a base composition of Ni-20 mass pct Cr-3 mass pct Mo that were precipitation strengthened by the γ' phase were studied in regards to their failure mechanisms as part of the fundamental research for achieving a creep rupture strength of 100 MPa at 1023 K (750 °C) and 105 hours. The microstructure, which was interrupted by transient creep, as well as the minimum creep rate and accelerated creep at 1123 K (850 °C) and 80 MPa was observed. The microstructure around the grain boundaries was altered remarkably with strain-induced grain boundary migration, while the γ' particle size increased linearly inside the grains with increasing temperature and time. Furthermore, the volume fraction of the γ' phase and the amount of precipitation on the grain boundary were associated with the size of the precipitate-free zone (PFZ), which is a major factor in creep damage. The appropriate precipitations inside the grains and at the grain boundaries were very effective for suppressing PFZ. Consequently, the creep properties can be improved by controlling PFZ in the proximity of grain boundaries for a superior balance of creep strength and ductility.

  16. Grain growth of Ni-based superalloy IN718 coating fabricated by pulsed laser deposition

    NASA Astrophysics Data System (ADS)

    Zhang, Yaocheng; Yang, Li; Dai, Jun; Huang, Zedong; Meng, Tao

    2016-06-01

    The pulsed laser deposited Ni-based superalloy coating was fabricated with successive 12 layers using single tracks. The microstructure of the deposited coating was observed by scanning electron microscopy (SEM). The grain growth and the grain boundary misorientation were investigated by electron backscatter diffraction (EBSD), the precipitation phase was determined by transmission electron microscope (TEM). The results showed that the dendrites were the most common microstructure in the coating, and the dendritic growth orientation was paralleled to the direction of the laser deposition. The dendrite got coarser and its space was increased with increasing laser deposited layers. Most grains grew along the preferential grain orientation <001> and formed anisotropy with grain boundaries misorientation angle about 2° in the pulsed laser deposited coating. The grain size along the texture orientation was 3-10 times larger than that in the transverse orientation. The cross section microhardness of the coating ranged between 240-280 HV, and decreased along the depositional direction due to the reasons of the variation of eutectic morphology, grain size distribution, grain misorientation and a small amounts of strengthening phase precipitation.

  17. Creep Properties and Deformation Mechanisms of a FGH95 Ni-based Superalloy

    NASA Astrophysics Data System (ADS)

    Xie, Jun; Tian, Su-gui; Zhou, Xiao-ming

    2013-07-01

    By means of full heat treatment, microstructure observation, lattice parameters determination, and the measurement of creep curves, an investigation has been conducted into the microstructure and creep mechanisms of FGH95 Ni-based superalloy. Results show that after the alloy is hot isostatically pressed, coarse γ' phase discontinuously distributes along the previous particle boundaries. After solution treatment at high temperature and aging, the grain size has no obvious change, and the amount of coarse γ' phase decreases, and a high volume fraction of fine γ' phase dispersedly precipitates in the γ matrix. Moreover, the granular carbides are found to be precipitated along grain boundaries, which can hinder the grain boundaries' sliding and enhance the creep resistance of the alloy. By x-ray diffraction analysis, it is indicated that the lattice misfit between the γ and γ' phases decreases in the alloy after full heat treatment. In the ranges of experimental temperatures and applied stresses, the creep activation energy of the alloy is measured to be 630.4 kJ/mol. During creep, the deformation mechanisms of the alloy are that dislocations slip in the γ matrix or shear into the γ' phase. Thereinto, the creep dislocations move over the γ' phase by the Orowan mechanism, and the < { 1 10 } rangle super-dislocation shearing into the γ' phase can be decomposed to form the configuration of (1/3) < { 1 12 } rangle super-Shockleys' partials and the stacking fault.

  18. Mechanisms of High Temperature/Low Stress Creep of Ni-Based Superalloy Single Crystals

    SciTech Connect

    Michael J. Mills

    2009-03-05

    Cast nickel-based superalloys are used for blades in land-based, energy conversion and powerplant applications, as well as in aircraft gas turbines operating at temperatures up to 1100 C, where creep is one of the life-limiting factors. Creep of superalloy single crystals has been extensively studied over the last several decades. Surprisingly, only recently has work focused specifically on the dislocation mechanisms that govern high temperature and low stress creep. Nevertheless, the perpetual goal of better engine efficiency demands that the creep mechanisms operative in this regime be fully understood in order to develop alloys and microstructures with improved high temperature capability. At present, the micro-mechanisms controlling creep before and after rafting (the microstructure evolution typical of high temperature creep) has occurred have yet to be identified and modeled, particularly for [001] oriented single crystals. This crystal orientation is most interesting technologically since it exhibits the highest creep strength. The major goal of the program entitled ''Mechanisms of High Temperature/Low Stress Creep of Ni-Based Superalloy Single Crystals'' (DOE Grant DE-FG02-04ER46137) has been to elucidate these creep mechanisms in cast nickel-based superalloys. We have utilized a combination of detailed microstructure and dislocation substructure analysis combined with the development of a novel phase-field model for microstructure evolution.

  19. The Portevin-Le Chatelier Effect in the Ni-Based Superalloy IN100

    NASA Astrophysics Data System (ADS)

    Fernandez-Zelaia, Patxi; Adair, Benjamin S.; Barker, Vincent M.; Antolovich, Stephen D.

    2015-12-01

    The Portevin-Le Chatelier (PLC) effect has been studied in the Ni-based superalloy IN100 which is currently used as a disk material in jet engines. A series of tensile tests was carried out at 588 K, 755 K, and 922 K (315 °C, 482 °C, and 649 °C) at plastic strain rates ranging from a low of 6.21 × 10-6 s-1 to a high of 4.92 × 10-2 s-1. The activation energy was determined using the slope of a line on a strain rate/temperature graph which divided the area of the graph into two regions: (1) "PLC behavior observed," and (2) "No PLC behavior observed." A new statistical approach was developed to objectively differentiate between a true PLC effect and experimental uncertainty ( i.e., "noise"). The value of the activation energy was found to be 1.14 eV/atom, which strongly suggests that the rate controlling process was bulk diffusion of C in the lattice. A qualitative model, based on the Orowan equation and slip band dislocation mechanics, was proposed, which unifies the seemingly disparate ideas of the process being controlled by a single atom/dislocation interaction while at the same time exhibiting significant strains during PLC load drops.

  20. Microstructure evolution and mechanical property of pulsed laser welded Ni-based superalloy

    NASA Astrophysics Data System (ADS)

    Ma, Guangyi; Wu, Dongjiang; Niu, Fangyong; Zou, Helin

    2015-09-01

    For evaluating the microstructure evolution and mechanical property of Ni-based Hastelloy C-276 weld joint by the pulsed laser welding, the influence of pulsed laser welding on the microstructure and mechanical property of the weld joint is investigated by the analysis of the microstructure morphology, microhardness, phase structure and tensile property. The results indicate that, in the fusion zone three sections are divided on the basis of the patterns of grain structures. In the weld joint, the element segregation is found, but the trend of brittle phase's formation is weakened. The weld microhardness presents just a little higher than that of base metal, and there is no obvious the softened heat affected zone. Meanwhile in the weld joint, the phase structure is still the face-center cubic with the tiny shift of peak positions and widened Full Width at Half-Maximum. The yield strength of weld joint is the same as that of base metal, and the tensile strength is nearly 90% of that of base metal. The decreased tensile strength is mainly attributed to the dislocation piling-up.

  1. Resistance to sulfur poisoning of Ni-based alloy with coinage (IB) metals

    NASA Astrophysics Data System (ADS)

    Xu, Xiaopei; Zhang, Yanxing; Yang, Zongxian

    2015-12-01

    The poisoning effects of S atom on the (1 0 0), (1 1 0) and (1 1 1) metal surfaces of pure Ni and Ni-based alloy with IB (coinage) metals (Cu, Ag, Au) are systematically studied. The effects of IB metal dopants on the S poisoning features are analyzed combining the density functional theory (DFT) results with thermodynamics data using the ab initio atomistic thermodynamic method. It is found that introducing IB doping metals into Ni surface can shift the d-band center downward from the Fermi level and weaken the adsorption of S on the (1 0 0) and (1 1 0) surfaces, and the S tolerance ability increases in the order of Ni, Cu/Ni, Ag/Ni and Au/Ni. Nevertheless, on the (1 1 1) surface, the S tolerance ability increases in the order of Ag/Ni (or Cu/Ni), Ni, and Au/Ni. When we increase the coverage of the IB metal dopants, we found that not only Au, but Cu and Ag can increase its S tolerance. We therefore propose that alloying can increase its S tolerance and alloying with Au would be a better way to increase the resistance to sulfur poisoning of the Ni anode as compared with the pure Ni and the Ag- or, Cu-doped Ni materials.

  2. Atomic-scale properties of Ni-based FCC ternary, and quaternary alloys

    DOE PAGESBeta

    Tamm, Artur; Aabloo, Alvo; Klintenberg, Mattias; Stocks, Malcolm; Caro, Alfredo

    2015-08-26

    The aim of our study is to characterize some atomic-scale properties of Ni-based FCC multicomponent alloys. For this purpose, we use Monte Carlo method combined with density functional theory calculations to study short-range order (SRO), atomic displacements, electronic density of states, and magnetic moments in equimolar ternary NiCrCo, and quaternary NiCrCoFe alloys. The salient features for the ternary alloy are a negative SRO parameter between Ni Cr and a positive between Cr Cr pairs as well as a weakly magnetic state. For the quaternary alloy we predict negative SRO parameter for Ni Cr and Ni Fe pairs and positive formore » Cr Cr and Fe Fe pairs. Atomic displacements for both ternary and quaternary alloys are negligible. In contrast to the ternary, the quaternary alloy shows a complex magnetic structure. The electronic structure of the ternary and quaternary alloys shows differences near the Fermi energy between a random solid solution and the predicted structure with SRO. Despite that, the calculated EXAFS spectra does not show enough contrast to discriminate between random and ordered structures. Finally, the predicted SRO has an impact on point-defect energetics, electron phonon coupling and thermodynamic functions and thus, SRO should not be neglected when studying properties of these two alloys.« less

  3. Solubility and Dissolution Rate of Ni Base Alloy to Molten Ag-Cu-Pd Brazing Filler

    NASA Astrophysics Data System (ADS)

    Ikeshoji, Toshi-Taka; Watanabe, Yuki; Suzumura, Akio; Yamazaki, Takahisa

    During the brazing process of the rocket engine’s nozzle skirt assembly made from Fe-Ni based super alloy pipes with Pd based brazing filler, the erosion corrosion pits were sometimes engraved on those pipes’ surface. The corrosion is considered to be assisted by the dynamic flow of the molten brazing filler. In order to estimate the amount of erosion corrosion and to prevent it, the solubility and the dissolution rate of Ni to the molten Ag-Cu-Pd brazing filler are measured experimentally. The Ni crucible poured with the Ag-Cu-Pd brazing filler was heated up to 1320K and quenched after the various keeping time. The microstructure of the solidified brazing filler part’s cross sections was observed, and the amount of the dissolved Ni was estimated using the image processing technique. The solubility was about 5.53mass%and the initial dissolution rate was 6.28 × 10-3mass%/s. Using these data, more elaborate dynamic flow simulation will be able to conduct.

  4. Photodissociation dynamics of organometallic compounds: Study of the dihydride complex H2Fe(CO)4

    SciTech Connect

    Heitz, M. C.; Daniel, C.

    1996-04-01

    The photodissociation of the dihydride complex H2Fe(CO)4 has been investigated by a theoretical approach, involving time-dependent wave packet propagations on potential energy surfaces (PES) obtained from CASSCF-MRCI calculations. A two dimensions simulation is proposed, allowing the study of two concurrents processes, namely photoinduced elimination of molecular hydrogen vs loss of a carbonyl ligand. Three singlet excited states {sup 1}bA1(x{sup 2}-y{sup 2}{yields}{sigma}g*), {sup 1}aB2(x{sup 2}-y{sup 2}{yields}{sigma}u*), {sup 1}aB1(yz{yields}{sigma}g*) has been identified in the range of energy corresponding to the experimental absorption spectrum. Wave packets propagations performed separately on the three PES describe the elementary processes contributing to the photochemical behavior of the molecule. The absorption spectrum reflecting these different processes, has been calculated, using the time dependent formalism.

  5. DISTRIBUTION OF ORGANIC AND ORGANOMETALLIC COMPOUNDS IN SEDIMENTS FROM THE GULF OF MEXICO

    EPA Science Inventory

    In 1994, over 200 sediment samples were collected in accordance with EPA's Environmental Monitoring and Assessment (EMAP) probabilistic sampling protocol from coastal and estuarine locations in the Louisianian Province (Gulf of Mexico). Organic extracts of homogenized aliquots we...

  6. Organometallic single source precursors for chemical vapor deposition of metal chalcogenides

    NASA Astrophysics Data System (ADS)

    Seidler, Dean Jerry

    The group 14--16 compounds with the general formula (Bn2SnE)3, (Bn3Sn)2E, and Bn 2Sn(EBn)2, where E = S or Se, were synthesized and investigated as potential single-source precursors for the preparation of tin chalcogenides. Each precursor was pyrolyzed under an inert atmosphere. Decomposition took place at relatively mild conditions (<400°C). The cyclic molecules, (Bn2SnS)3 and (Bn2SnSe)3, produced tin sulfide and tin selenide, respectively. The samples were XRD phase pure, and combustion analysis indicated less than 1% carbon present in the final product. The acyclic precursors, (Bn3Sn)2S and (Bn 3Sn)2Se, yielded a mixture of the tin chalcogenide and elemental tin with carbon content <1%. The pyrolysis of Bn2Sn(SBn) 2 and Bn2Sn(SeBn)2 produced SnS2 and SnSe2, respectively, with carbon contamination <3%. The only volatile by-product detected from the pyrolysis of these compounds was bibenzyl, indicating all of the tin and chalcogen were left behind in the solid state product. Solid solutions could be generated by combining (Bn 2SnS)3 and (Bn2SnSe)3, and pyrolyzing the mixture. Combinations of Bn2Sn(SBn)2 and Bn 2Sn(SeBn)2 yielded products with some solid solution character; however, some phase separation was indicated in the XRD patterns. Bn3SnSBn and (tert-Bu2SnS)2 were pyrolyzed to produce bulk samples of SnS and also used as single-source precursors for the chemical vapor deposition of thin films of SnS on glass and halite substrates. The composition and morphology of the products, both as bulk materials and thin films, were influenced by the structure of the organometallic precursor, the nature of the leaving group attached to the metal (or chalcogen), and the nature of the film substrate.

  7. Automated detection and characterization of microstructural features: application to eutectic particles in single crystal Ni-based superalloys

    NASA Astrophysics Data System (ADS)

    Tschopp, M. A.; Groeber, M. A.; Fahringer, R.; Simmons, J. P.; Rosenberger, A. H.; Woodward, C.

    2010-03-01

    Serial sectioning methods continue to produce an abundant amount of image data for quantifying the three-dimensional nature of material microstructures. Here, we discuss a methodology to automate detecting and characterizing eutectic particles taken from serial images of a production turbine blade made of a heat-treated single crystal Ni-based superalloy (PWA 1484). This method includes two important steps for unassisted eutectic particle characterization: automatically identifying a seed point within each particle and segmenting the particle using a region growing algorithm with an automated stop point. Once detected, the segmented eutectic particles are used to calculate microstructural statistics for characterizing and reconstructing statistically representative synthetic microstructures for single crystal Ni-based superalloys. The significance of this work is its ability to automate characterization for analysing the 3D nature of eutectic particles.

  8. New organic and organometallic salts for second-order nonlinear optics

    NASA Technical Reports Server (NTRS)

    Marder, Seth R.; Perry, Joseph W.; Tiemann, Bruce G.; Schaefer, William P.; Groves, Paul C.

    1989-01-01

    A series of organometallic and organic salts, in which the cation has been designed to have a large molecular hyperpolarizability, has been prepared. Variation of the counterion (anion) in many cases leads to materials with large powder second harmonic generation (SHG) efficiencies, the highest of which is roughly 2000 times that of a urea reference.

  9. Immobilization of two organometallic complexes into a single cage to construct protein-based microcompartments.

    PubMed

    Maity, Basudev; Fukumori, Kazuki; Abe, Satoshi; Ueno, Takafumi

    2016-04-01

    Natural protein-based microcompartments containing multiple enzymes promote cascade reactions within cells. We use the apo-ferritin protein cage to mimic such biocompartments by immobilizing two organometallic Ir and Pd complexes into the single protein cage. Precise locations of the metals and their accumulation mechanism were studied by X-ray crystallography. PMID:27021005

  10. Reaction of Glyconitriles with Organometallic Reagents: Access to Acyl β-C-Glycosides.

    PubMed

    Guisot, Nicolas E S; Ella Obame, Idriss; Ireddy, Prathap; Nourry, Arnaud; Saluzzo, Christine; Dujardin, Gilles; Dubreuil, Didier; Pipelier, Muriel; Guillarme, Stéphane

    2016-03-18

    A new strategy for the synthesis of acyl β-C-glycosides is described. The reactivity of glyconitriles toward organometallic reagents such as organomagnesium or organolithium derivatives was studied, affording acyl β-C-glycosides in moderate to good yields. In this study, glycal formation was efficiently prevented by deprotonating the hydroxyl group in position 2 of the glyconitriles during the process. PMID:26926714

  11. Organometallic macromolecules with piano stool coordination repeating units: chain configuration and stimulated solution behaviour.

    PubMed

    Cao, Kai; Ward, Jonathan; Amos, Ryan C; Jeong, Moon Gon; Kim, Kyoung Taek; Gauthier, Mario; Foucher, Daniel; Wang, Xiaosong

    2014-09-11

    Theoretical calculations illustrate that organometallic macromolecules with piano stool coordination repeating units (Fe-acyl complex) adopt linear chain configuration with a P-Fe-C backbone surrounded by aromatic groups. The macromolecules show molecular weight-dependent and temperature stimulated solution behaviour in DMSO. PMID:25036387

  12. Application of Organometallic Catalysis to the Commercial Production of L-DOPA.

    ERIC Educational Resources Information Center

    Knowles, W. S.

    1986-01-01

    Shows how asymmetric organometallic catalysts can be used to make complex organic molecules with extremely high enantioselectivity. The molecule considered is l-3, 4-dihydroxyphenylalanine (L-DOPA), an amino acid which was found to be effective in the treatment of Parkinson's disease. (JN)

  13. Highly selective electrocatalytic dehydrogenation at low applied potential catalyzed by an Ir organometallic complex.

    PubMed

    Bonitatibus, Peter J; Rainka, Matthew P; Peters, Andrea J; Simone, Davide L; Doherty, Mark D

    2013-11-21

    A homogeneous organometallic Ir complex was shown to catalyze the electro-oxidation of 4-methoxybenzyl alcohol to p-anisaldehyde at a very low applied potential with remarkably high selectivity and Faradaic efficiency. In the chemical catalysis, when stoichiometric oxidant and anionic base were used to separately accept electrons and protons, aldehyde selectivity was in agreement with electrolysis results. PMID:24091876

  14. Determination of cleavage planes and fracture characterization of Ni-based single crystal superalloys

    NASA Technical Reports Server (NTRS)

    Merrill, John M.; Wilcox, Roy C.

    1992-01-01

    The room temperature fracture behavior of the Ge Rene N-4, CMSX-2, and CMSX-4C single crystal Ni-based superalloys was studied. All crystals were grown along the (001) direction and tensile tested in both helium and hydrogen atmospheres. A stereoscopic technique developed for use with a scanning electron microscope was applied to determine cleavage planes. Planar gamma(') morphologies also were examined to help determine cleavage planes. Helium charged specimens failed on a number of planes including the (111), (110), and (320). In most cases planes of the (111)-type initiated at the notch region and became smaller and smaller as they moved in radially. Tensile strengths in helium averaged 1000 MPa higher than that of the hydrogen charged specimens. Specimens tested in hydrogen generally failed on (100)-type planes originating from the notch region. This (100) region comprised 60 to 80 percent of the total fracture surface on most samples and appeared as large flat planes perpendicular to the growth direction of the crystal. The interior regions contained (100)-type planes as well as (321), (320), (210), and (111)-types. Hydrogen charged specimens also showed a high percentage of large cracks oriented at 90 deg to one another, indicative of the (100)-type fracture. The Ge Rene N4 and the CMSX-4C samples contained 3-5 percent gamma/gamma(') eutectic, while the CMSX-2 samples had little or no gamma/gamma(') eutectic. The relationship between gamma/gamma(') eutectic and the fracture surface has not been fully determined, but it is thought that the gamma/gamma(') eutectic may serve as a possible trapping site for hydrogen.

  15. Magnetic Properties of FeNi-Based Thin Film Materials with Different Additives.

    PubMed

    Liang, Cai; Gooneratne, Chinthaka P; Wang, Qing Xiao; Liu, Yang; Gianchandani, Yogesh; Kosel, Jurgen

    2014-09-01

    This paper presents a study of FeNi-based thin film materials deposited with Mo, Al and B using a co-sputtering process. The existence of soft magnetic properties in combination with strong magneto-mechanical coupling makes these materials attractive for sensor applications. Our findings show that FeNi deposited with Mo or Al yields magnetically soft materials and that depositing with B further increases the softness. The out-of-plane magnetic anisotropy of FeNi thin films is reduced by depositing with Al and completely removed by depositing with B. The effect of depositing with Mo is dependent on the Mo concentration. The coercivity of FeNiMo and FeNiAl is reduced to less than a half of that of FeNi, and a value as low as 40 A/m is obtained for FeNiB. The surfaces of the obtained FeNiMo, FeNiAl and FeNiB thin films reveal very different morphologies. The surface of FeNiMo shows nano-cracks, while the FeNiAl films show large clusters and fewer nano-cracks. When FeNi is deposited with B, a very smooth morphology is obtained. The crystal structure of FeNiMo strongly depends on the depositant concentration and changes into an amorphous structure at a higher Mo level. FeNiAl thin films remain polycrystalline, even at a very high concentration of Al, and FeNiB films are amorphous, even at a very low concentration of B. PMID:25587418

  16. Gamma prime precipitation mechanisms and solute partitioning in Ni-base alloys

    NASA Astrophysics Data System (ADS)

    Rojhirunsakool, Tanaporn

    Nickel-base superalloys have been emerged as materials for gas turbines used for jet propulsion and electricity generation. The strength of the superalloys depends mainly from an ordered precipitates of L12 structure, so called gamma prime (gamma') dispersed within the disorder gamma matrix. The Ni-base alloys investigated in this dissertation comprise both model alloy systems based on Ni-Al-Cr and Ni-Al-Co as well as the commercial alloy Rene N5. Classical nucleation and growth mechanism dominates the gamma' precipitation process in slowed-cooled Ni-Al-Cr alloys. The effect of Al and Cr additions on gamma' precipitate size distribution as well as morphological and compositional development of gamma' precipitates were characterized by coupling transmission electron microscopy (TEM) and 3D atom probe (3DAP) techniques. Rapid quenching Ni-Al-Cr alloy experiences a non-classical precipitation mechanism. Structural evolution of the gamma' precipitates formed and subsequent isothermal annealing at 600 °C were investigated by coupling TEM and synchrotron-based high-energy xray diffraction (XRD). Compositional evolution of the non-classically formed gamma' precipitates was determined by 3DAP and Langer, Bar-on and Miller (LBM) method. Besides homogeneous nucleation, the mechanism of heterogeneous gamma' precipitation involving a discontinuous precipitation mechanism, as a function of temperature, was the primary focus of study in case of the Ni-Al-Co alloy. This investigation coupled SEM, SEM-EBSD, TEM and 3DAP techniques. Lastly, solute partitioning and enrichment of minor refractory elements across/at the gamma/ gamma' interfaces in the commercially used single crystal Rene N5 superalloy was investigated by using an advantage of nano-scale composition investigation of 3DAP technique.

  17. Density functional theory study of the thermodynamic and elastic properties of Ni-based superalloys

    NASA Astrophysics Data System (ADS)

    Wu, Xiaoxia; Wang, Chongyu

    2015-07-01

    The thermophysical properties of Ni-based single-crystal superalloys were investigated using first-principles calculations combined with the quasiharmonic approximation. The effect of alloying elements X (X = Re, Ru, Ta, W, Mo, Cr, and Co) on the thermophysical properties of the γ-Ni and γ‧-Ni3Al phases was investigated. The calculations showed that alloying can effectively adjust the lattice misfit between the two phases, and Cr can suppress lattice misfit and may improve the creep resistance of alloys. At 0 K, doping with refractory elements leads to tetragonal shear softening of the γ-Ni phase. For γ-Ni, Re, Ru, Cr, and Co slightly increase c44, while Mo, W, and Ta decrease c44. Importantly, high-temperature relative hardening was found to occur close to the service temperature of the superalloy, at which Ru and Cr increase c‧ and Mo and W increase c44 of γ-Ni. For the γ‧-Ni3Al phase, all of the alloying elements except Co considerably increase c‧ and c44. Re and W at the Al site were found to most effectively harden the γ‧-Ni3Al phase. The thermophysical and elastic properties were fully understood by analysis of the electronic structures and phonon spectra. It was found that the electronic density of states (DOS) can account for elastic hardening due to alloying. The phonon spectra along with electronic DOS analysis showed that alloying not only strengthens the first nearest neighbor Ni-X bond through additional d-d hybridization, but it is also important for stiffening the second nearest neighbor Al-X bonding through p-band filling.

  18. Corrosion behavior of Ni-based structural materials for electrolytic reduction in lithium molten salt

    NASA Astrophysics Data System (ADS)

    Cho, Soo Haeng; Park, Sung Bin; Lee, Jong Hyeon; Hur, Jin Mok; Lee, Han Soo

    2011-05-01

    In this study, the corrosion behavior of new Ni-based structural materials was studied for electrolytic reduction after exposure to LiCl-Li 2O molten salt at 650 °C for 24-216 h under an oxidizing atmosphere. The new alloys with Ni, Cr, Al, Si, and Nb as the major components were melted at 1700 °C under an inert atmosphere. The melt was poured into a preheated metallic mold to prepare an as-cast alloy. The corrosion products and fine structures of the corroded specimens were characterized by scanning electron microscope (SEM), Energy Dispersive X-ray Spectroscope (EDS), and X-ray diffraction (XRD). The corrosion products of as cast and heat treated low Si/high Ti alloys were Cr 2O 3, NiCr 2O 4, Ni, NiO, and (Al,Nb,Ti)O 2; those of as cast and heat treated high Si/low Ti alloys were Cr 2O 3, NiCr 2O 4, Ni, and NiO. The corrosion layers of as cast and heat treated low Si/high Ti alloys were continuous and dense. However, those of as cast and heat treated high Si/low Ti alloys were discontinuous and cracked. Heat treated low Si/high Ti alloy showed the highest corrosion resistance among the examined alloys. The superior corrosion resistance of the heat treated low Si/high Ti alloy was attributed to the addition of an appropriate amount of Si, and the metallurgical evaluations were performed systematically.

  19. In vitro and in vivo evaluation of porous TiNi-based alloy as a scaffold for cell tissue engineering.

    PubMed

    Kokorev, Oleg V; Hodorenko, Valentina N; Chekalkin, Timofey L; Kim, Ji-Soon; Kang, Seung-Baik; Dambaev, Georgiy Ts; Gunther, Victor E

    2016-01-01

    This study aims to look into the applicability of a porous TiNi-based shape memory alloy (SMA) scaffold as an incubator for bone marrow mesenchymal cells, hepatocytes, and pancreatic islet cells. The porous TiNi-based SMA used was fabricated using a self-propagating high-temperature synthesis (SHS) technique, in which scaffold blocks measuring 4 × 4 × 10 mm were prepared. In vitro tests were done using mesenchymal stem cells (MSC) isolated from mature bone marrow of CBA/j inbred mice, and cultured in 3 different culture media - Control medium, Osteogenic medium, and Chondrogenic medium. Hepatocytes and islet cells were isolated from the livers and pancreatic glands of Wistar rats respectively, seeded on porous TiNi-based SMA scaffolds, and cultured. The scaffolds were then implanted into the abdominal cavity of Wistar rats and later harvested, at days 7, 14, 21, and 28, post-implantation. SEM imaging was performed with pre-implanted scaffolds at day 0 and harvested scaffolds at days 7, 14, 21, and 28, post-implantation. Based on weight increase percentages, the in vitro study revealed that the osteogenic group showed a 2-fold increase, and the chondrogenic group showed a 1.33-fold increase, compared to the control group. The in vivo study, on the other hand, showed that from day 7 post-implantation, the cellular in-growth gradually invaded the inner porous structure from the periphery towards the center, and at day-28 post-implantation, all pores were closed and completely filled with cells and the extracellular matrix. The results show that porous TiNi-based SMA is a unique biocompatible incubator for cell cultures and can be successfully used for tissue bioengineering and artificial organs. PMID:25613028

  20. Electrochemical performance and capacity degradation mechanism of single-phase La-Mg-Ni-based hydrogen storage alloys

    NASA Astrophysics Data System (ADS)

    Liu, Jingjing; Li, Yuan; Han, Da; Yang, Shuqin; Chen, Xiaocui; Zhang, Lu; Han, Shumin

    2015-12-01

    La-Mg-Ni-based hydrogen storage alloys are a promising candidate for the negative electrode materials of nickel metal hydride batteries. However, their fast capacity degradation hinders them from more extensive application. In this study, the electrochemical performance and capacity degradation mechanism of single-phase La2MgNi9, La3MgNi14 and La4MgNi19 alloys are studied from the perspective of their constituent subunits. It is found that the rate capability and cycling stability of the alloy electrodes increase with higher [LaNi5]/[LaMgNi4] subunit ratio, while the discharge capacity shows a reverse trend. Degradation study shows that the inter-molecular strains in the alloys are the main reason that leads to the fast capacity degradation of La-Mg-Ni-based alloys. The strains are caused by the difference in the expansion/contraction properties between [LaNi5] and [LaMgNi4] subunits during charge/discharge which is mainly observed in the H-dissolved solid solution instead of hydride. It is also found that the strains can be relieved by adjusting [LaNi5]/[LaMgNi4] subunit ratio of the alloys, thus achieving less pulverization and oxidation, and better cycling stability. We expect our findings can inspire new thoughts on improving the electrochemical performance of La-Mg-Ni-based alloys by tuning their superlattice structures.

  1. Effect of La2O3 Addition on Microstructure and Wear Behavior of Electrospark Deposited Ni-BASED Coatings

    NASA Astrophysics Data System (ADS)

    Yuxin, Gao; Jian, Yi

    2013-12-01

    La2O3 doped Ni-based coatings have been prepared by electrospark deposition technique. The effect of La2O3 on the microstructure, hardness and wear behavior of the as-prepared Ni-based coatings is investigated by using X-ray diffractometer, scanning electron microscope, wear tribometer and Vickers hardness tester. Results indicates that the microstructure, hardness and wear resistance of La2O3 doped Ni-based coatings are effectively improved as compared to the undoped one, and the coating with the addition of 2.5 wt.% La2O3 shows the optimal improvement effects. The addition of La2O3 can reduce the defects, refine grains and increase hardness of the coating, which can inhibit the nucleation and propagation of cracking, consequently resist cutting and fracture during the wear process. Moreover, the addition of La2O3 leads to changes in abrasion mechanism of the coatings, and the reasons resulting in different abrasion mechanisms are discussed.

  2. Enhancing Sulfur Tolerance of Ni-Based Cermet Anodes of Solid Oxide Fuel Cells by Ytterbium-Doped Barium Cerate Infiltration.

    PubMed

    Li, Meng; Hua, Bin; Luo, Jing-Li; Jiang, San Ping; Pu, Jian; Chi, Bo; Li, Jian

    2016-04-27

    Conventional anode materials for solid oxide fuel cells (SOFCs) are Ni-based cermets, which are highly susceptible to deactivation by contaminants in hydrocarbon fuels. Hydrogen sulfide is one of the commonly existed contaminants in readily available natural gas and gasification product gases of pyrolysis of biomasses. Development of sulfur tolerant anode materials is thus one of the critical challenges for commercial viability and practical application of SOFC technologies. Here we report a viable approach to enhance substantially the sulfur poisoning resistance of a Ni-gadolinia-doped ceria (Ni-GDC) anode through impregnation of proton conducting perovskite BaCe0.9Yb0.1O3-δ (BCYb). The impregnation of BCYb nanoparticles improves the electrochemical performance of the Ni-GDC anode in both H2 and H2S containing fuels. Moreover, more importantly, the enhanced stability is observed in 500 ppm of H2S/H2. The SEM and XPS analysis indicate that the infiltrated BCYb fine particles inhibit the adsorption of sulfur and facilitate sulfur removal from active sites, thus preventing the detrimental interaction between sulfur and Ni-GDC and the formation of cerium sulfide. The preliminary results of the cell with the BCYb+Ni-GDC anode in methane fuel containing 5000 ppm of H2S show the promising potential of the BCYb infiltration approach in the development of highly active and stable Ni-GDC-based anodes fed with hydrocarbon fuels containing a high concentration of sulfur compounds. PMID:27052726

  3. Effects of electroless composite plating Ni-Cu-P on the electrochemical properties of La-Mg-Ni-based hydrogen storage alloy

    NASA Astrophysics Data System (ADS)

    Yang, Shuqin; Liu, Hongping; Han, Shumin; Li, Yuan; Shen, Wenzhuo

    2013-04-01

    In order to improve the overall electrochemical performances of La-Mg-Ni-based hydrogen storage alloy, electroless composite plating Ni-Cu-P treatment was applied to La0.88Mg0.12Ni2.95Mn0.10Co0.55Al0.10 alloy powders. SEM observation showed that the composite treatment resulted in spherical particles more densely depositing on the alloy surface, and subsequently EDS analysis indicated that the particles should be Ni-Cu-P compounds. These particle coatings enhanced the conductivity and the catalytic activity, besides acting as a protective layer, thereby improving the electrochemical properties of the alloy. The discharge capacity of the alloy electrode noticeably increased from 338 mA/g to 361 mA/g. The capacity retention after 200 charge/discharge cycles and the high rate dischargeability (HRD) at 1500 mA/g discharge current density of the alloy electrode increased from 76.0% and 27.7% to 84.8% and 37.0%, respectively. The superior HRD value is believed to be ascribed to the improved kinetics from the compact metallic layers on the surface.

  4. Confined Synthesis of Organometallic Chains and Macrocycles by Cu-O Surface Templating.

    PubMed

    Fan, Qitang; Dai, Jingya; Wang, Tao; Kuttner, Julian; Hilt, Gerhard; Gottfried, J Michael; Zhu, Junfa

    2016-03-22

    The bottom-up construction of low-dimensional macromolecular nanostructures directly on a surface is a promising approach for future application in molecular electronics and integrated circuit production. However, challenges still remain in controlling the formation of these nanostructures with predetermined patterns (such as linear or cyclic) or dimensions (such as the length of one-dimensional (1D) chains). Here, we demonstrate that a high degree of structural control can be achieved by employing a Cu(110)-(2×1)O nanotemplate for the confined synthesis of organometallic chains and macrocycles. This template contains ordered arrays of alternating stripes of Cu-O chains and bare Cu, the widths of which are controllable. Using scanning tunneling microscopy and low-energy electron diffraction, we show that well-defined, ordered 1D zigzag organometallic oligomeric chains with uniform lengths can be fabricated on the Cu stripes (width >5.6 nm) of the Cu(110)-(2×1)O surface. In addition, the lengths of the meta-terphenyl (MTP)-based chains can be adjusted by controlling the widths of the Cu stripes within a certain range. When reducing the widths of Cu stripes to a range of 2.6 to 5.6 nm, organometallic macrocycles including tetramer (MTP-Cu)4, hexamer (MTP-Cu)6, and octamer (MTP-Cu)8 species are formed due to the spatial confinement effect and attraction to the Cu-O chains. An overview of all formed organometallic macrocycles on the Cu stripes with different widths reveals that the origin of the formation of these macrocycles is the cis-configured organometallic dimer (MTP)2Cu3, which was observed on the extremely narrow Cu stripe with a width of 1.5 nm. PMID:26928582

  5. Do Organometallic CH4-Me(+p) Adducts and X4H(+) (X = P, As) Clusters Undergo Two-Electron Three-Center Interactions? Some Aspects of Discussion.

    PubMed

    Lobayan, Rosana M; Bochicchio, Roberto C

    2015-07-01

    Most of the systems possessing true two-electron three-center interactions are electron deficient compounds like boron hydrids, closo-boranes, and some organic ions such as butonium cations. In this work, we perform a detailed study of the electron distribution for two different types of systems to which likewise interactions has been adjudicated: organometallic CH4-Me(+p) (p = 1, 2) adducts with Me, alkaline and earth alkaline metallic ions of Li, Na, K, Be, Mg, Ca in their stable gaseous phase and X4H(+) (X = P, As) simple clusters. For this purpose, topological analysis of the electron density decomposed into its effectively paired and unpaired contributions has been carried out looking for complex interactions. PMID:26061421

  6. Fast Electron Transfer Exchange at Self-Assembled Monolayers of Organometallic Ruthenium(II) σ-Arylacetylide Complexes.

    PubMed

    Mulas, Andrea; Hervault, Yves-Marie; He, Xiaoyan; Di Piazza, Emmanuel; Norel, Lucie; Rigaut, Stéphane; Lagrost, Corinne

    2015-06-30

    A new series of ruthenium organometallic carbon-rich complexes, exhibiting fast electron transfer kinetics combined to a low oxidation potential, was synthesized for self-assembled monolayer (SAM) formation on gold surfaces. The molecules consist of highly conjugated ruthenium(II) mono(σ-arylacetylide) or bis(σ-arylacetylide) complexes functionalized with different bridge units with specific (protected) anchoring groups that possess high affinity for gold, such as thiol, carbodithioate, and isocyanide. Single component and mixed SAMs were prepared and fully characterized by wettability studies, infrared reflection absorption spectroscopy (IRRAS), X-ray photoelectron spectroscopy (XPS), and electrochemical analyses. By applying the Laviron's formalism, fast electron transfer kinetics (≈10(4) s(-1)) were found at the derived self-assemblies while no significant effect could have been evidenced with variation of the bridging unit and of the anchoring moiety. Interestingly, a hexyl aliphatic spacer in the bridging unit with a thiol group and dilution with suitable nonelectroactive thiols lead to better SAM organization and packing, in comparison with undiluted complexes with shorter spacers. Such features make these compounds suitable alternatives to the widely used ferrocene center as redox-active building blocks for reversible charge storage devices. PMID:26053314

  7. Convergent study of Ru-ligand interactions through QTAIM, ELF, NBO molecular descriptors and TDDFT analysis of organometallic dyes

    NASA Astrophysics Data System (ADS)

    Sánchez-Coronilla, Antonio; Sánchez-Márquez, Jesús; Zorrilla, David; Martín, Elisa I.; de los Santos, Desireé M.; Navas, Javier; Fernández-Lorenzo, Concha; Alcántara, Rodrigo; Martín-Calleja, Joaquín

    2014-08-01

    We report a theoretical study of a series of Ru complexes of interest in dye-sensitised solar cells, in organic light-emitting diodes, and in the war against cancer. Other metal centres, such as Cr, Co, Ni, Rh, Pd, and Pt, have been included for comparison purposes. The metal-ligand trends in organometallic chemistry for those compounds are shown synergistically by using three molecular descriptors: quantum theory of atoms in molecules (QTAIM), electron localisation function (ELF) and second-order perturbation theory analysis of the natural bond orbital (NBO). The metal-ligand bond order is addressed through both delocalisation index (DI) of QTAIM and fluctuation index (λ) of ELF. Correlation between DI and λ for Ru-N bond in those complexes is introduced for the first time. Electron transfer and stability was also assessed by the second-order perturbation theory analysis of the NBO. Electron transfer from the lone pair NBO of the ligands toward the antibonding lone pair NBO of the metal plays a relevant role in stabilising the complexes, providing useful insights into understanding the effect of the 'expanded ligand' principle in supramolecular chemistry. Finally, absorption wavelengths associated to the metal-to-ligand charge transfer transitions and the highest occupied molecular orbital (HOMO)--lowest unoccupied molecular orbital (LUMO) characteristics were studied by time-dependent density functional theory.

  8. Nanoscaled tin dioxide films processed from organotin-based hybrid materials: an organometallic route toward metal oxide gas sensors.

    PubMed

    Renard, Laetitia; Babot, Odile; Saadaoui, Hassan; Fuess, Hartmut; Brötz, Joachim; Gurlo, Aleksander; Arveux, Emmanuel; Klein, Andreas; Toupance, Thierry

    2012-11-01

    Nanocrystalline tin dioxide (SnO(2)) ultra-thin films were obtained employing a straightforward solution-based route that involves the calcination of bridged polystannoxane films processed by the sol-gel process from bis(triprop-1-ynylstannyl)alkylene and -arylene precursors. These films have been thoroughly characterized by FTIR, contact angle measurements, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), atomic force (AFM) and scanning electron (SEM) microscopies. Annealing at a high temperature gave 30-35 nm thick cassiterite SnO(2) films with a mean crystallite size ranging from 4 to 7 nm depending on the nature of the organic linker in the distannylated compound used as a precursor. In the presence of H(2) and CO gases, these layers led to highly sensitive, reversible and reproducible responses. The sensing properties were discussed in regard to the crystallinity and porosity of the sensing body that can be tuned by the nature of the precursor employed. Organometallic chemistry combined with the sol-gel process therefore offers new possibilities toward metal oxide nanostructures for the reproducible and sensitive detection of combustible and toxic gases. PMID:23011110

  9. MICROSTRUCTURE OF LONG-TERM AGED IN617 NI-BASE SUPERALLOY

    SciTech Connect

    Wu, Quanyan; Shingledecker, John P; Vasudevan, Vijay; Swindeman, Robert W

    2008-01-01

    The microstructure of the Ni-base superalloy IN617 that had undergone prolonged aging (approximately 65,000 hours) at a series of temperatures from 482 C to 871 C has been characterized by microhardness measurements, optical microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Cr23C6, Mo-rich eta-M6C, and Ti(C,N) constitute the major primary coarse precipitates both within the grains and along the grain boundaries. The secondary carbides were mostly fine Cr23C6, which had a cube-on-cube orientation relationship (OR) with the fcc matrix, and at long times were present in cuboidal and plate-shape forms within the grains and as films along the grain boundaries. Fine, eta-M6C carbides were also observed at low to intermediate temperatures with an OR given by [011] carbide//[011] matrix, carbide// matrix. The coarse eta-M6C carbides increased in extent at 871 C, whereas the counterpart fine carbides were absent. The phase was found to be present at all aging temperatures up to 871 C, with a volume fraction ranging from very low to approximately 5 pct at 593 C, where the peak in microhardness occurs. The observations have also suggested that the presence of a very small amount of at temperatures as high as 871 C at long times may be associated with a reaction between the fine eta-carbides and the matrix. Ultrafine precipitates of the intermetallic phase Ni2(Cr,Mo) with the Pt2Mo-type structure was observed in addition to in samples aged for 28,300 hours at the lowest aging temperature of 482 C. These precipitates were absent in samples aged at higher temperatures. The various observations made have suggested that the long-term thermal stability of the IN617 alloy is reasonably good over a wide temperature range of 538 C to 704 C, whereas at higher temperatures (871 C), the substantial decrease in the volume fraction of and coarsening and clustering of the carbides lead to a large drop in the microhardness. A modified time

  10. Room temperature synthesis of Ni-based alloy nanoparticles by radiolysis.

    SciTech Connect

    Nenoff, Tina Maria; Berry, Donald T.; Lu, Ping; Leung, Kevin; Provencio, Paula Polyak; Stumpf, Roland Rudolph; Huang, Jian Yu; Zhang, Zhenyuan

    2009-09-01

    Room temperature radiolysis, density functional theory, and various nanoscale characterization methods were used to synthesize and fully describe Ni-based alloy nanoparticles (NPs) that were synthesized at room temperature. These complementary methods provide a strong basis in understanding and describing metastable phase regimes of alloy NPs whose reaction formation is determined by kinetic rather than thermodynamic reaction processes. Four series of NPs, (Ag-Ni, Pd-Ni, Co-Ni, and W-Ni) were analyzed and characterized by a variety of methods, including UV-vis, TEM/HRTEM, HAADF-STEM and EFTEM mapping. In the first focus of research, AgNi and PdNi were studied. Different ratios of Ag{sub x}- Ni{sub 1-x} alloy NPs and Pd{sub 0.5}- Ni{sub 0.5} alloy NP were prepared using a high dose rate from gamma irradiation. Images from high-angle annular dark-field (HAADF) show that the Ag-Ni NPs are not core-shell structure but are homogeneous alloys in composition. Energy filtered transmission electron microscopy (EFTEM) maps show the homogeneity of the metals in each alloy NP. Of particular interest are the normally immiscible Ag-Ni NPs. All evidence confirmed that homogeneous Ag-Ni and Pd-Ni alloy NPs presented here were successfully synthesized by high dose rate radiolytic methodology. A mechanism is provided to explain the homogeneous formation of the alloy NPs. Furthermore, studies of Pd-Ni NPs by in situ TEM (with heated stage) shows the ability to sinter these NPs at temperatures below 800 C. In the second set of work, CoNi and WNi superalloy NPs were attempted at 50/50 concentration ratios using high dose rates from gamma irradiation. Preliminary results on synthesis and characterization have been completed and are presented. As with the earlier alloy NPs, no evidence of core-shell NP formation occurs. Microscopy results seem to indicate alloying occurred with the CoNi alloys. However, there appears to be incomplete reduction of the Na{sub 2}WO{sub 4} to form the W

  11. Organometallic Nanostructures of 1,4-DIBROMO-2,5-DIIODOBENZENE by Metal Ions Construction on Hopg Surface

    NASA Astrophysics Data System (ADS)

    Li, Wei; Wang, Zhongping; Leng, Xinli; Lu, Yan; Liu, Xiaoqing; Wang, Li

    2016-03-01

    Different organometallic nanostructures on highly oriented pyrolytic graphite (HOPG) have been synthesized by different metal ions coordinating with 1,4-Dibromo-2,5-diiodobenzene (C6H2Br2I2). Scanning tunneling microscopy (STM) images directly demonstrated the transformation of the nanostructure from self-assembled nanostructures formed by C6H2Br2I2 through halogen bond into organometallic network, formed by the dehalogenated C6H2Br2I2 molecules covalent bonded with metal ions. Moreover, by varying the concentrations of C6H2Br2I2 molecules or valence states of metal ions, organometallic structures with different shapes and sizes have been fabricated, which illustrates that the concentrations and valence states of the metal ions play important roles in the organometallic nanostructures.

  12. The Development and Study of Surface Bound Ruthenium Organometallic Complexes

    NASA Astrophysics Data System (ADS)

    Abbott, Geoffrey Reuben

    The focus of this project has been on the use of mono-diimine ruthenium organometallic complexes, of the general structure [H(Ru)(CO)(L)2(L') 2][PF6] (L=PPh3, DPPENE and L'=Bpy, DcBpy, MBpyC, Phen, AminoPhen) bound to surfaces as luminescent probes. Both biological and inorganic/organic hybrid surfaces have been studied. The complexes were characterized both bound and unbound using standard analytical techniques such as NMR, IR and X-ray crystallography, as well as through several photophysical methods as well. Initially the study focused on how the photophyscial properties of the complexes were affected by incorporation into biological membranes. It was found that by conjugating the probes to a more rigid cholesterol moiety that luminescence was conserved, compared to conjugation with a far more flexible lipid moiety, where luminescence was either lost or reduced. Both the cholesterol and lipid conjugates were able to insert into a lipid membrane, and in the more rigid environment some of the lipid conjugates regained some of their luminescence, but often blue shifted and reduced, depending on the conjugation site. Silica Polyamine Composites (SPCs) were a hybrid material developed in the Rosenberg Lab as useful metal separation materials, that could be easily modified, and had several benefits over current commercially available polymers, or inorganic materials. These SPCs also provided an opportunity for the development of a heterogeneous platform for luminescent complexes as either catalysts or sensors. Upon binding of the luminescent Ru complexes to the surface no loss, or major change in luminescence was seen, however, when bound to the rigid surface a significant increase in excited state lifetime was measured. It is likely that through binding and interacting with the surface that the complexes lost non-radiative decay pathways, resulting in the increase in lifetime, however, these interactions do not seem to affect the energy level of the MLCT band in a

  13. Shape-Controlled Synthesis of Ni-Based Nanoparticles and Patterning for Carbon Nanofiber Growth

    NASA Astrophysics Data System (ADS)

    Sarac, Mehmet Fahri

    nickel phosphide were investigated. Ni3C1-x NPs were synthesized through thermolysis of nickel acetylacetonate, with oleylamine as a reducing agent and 1-octadecene (ODE) as the solvent. Trioctylephosphine (TOP) was added as ligand and inhibited the formation of dendritic shapes, as well as inhibiting the incorporation of carbon. This was found to create Ni NPs which were spherical, while comparable findings have been observed from the use of octadecane (ODA) and trioctylphosphine oxide (TOPO) as solvents, but these have been observed to have fewer, larger branches than when using ODE, while producing Ni rather than Ni3C 1-x NPs at 230 °C. Incorporating carbon from TOPO or ODA in Ni NPs required higher temperatures, while conversion of the dendritic NPs through this approach led to several voids in branches (rather than larger single voids for the spherical NPs). These studies have generated important knowledge about the synthesis of Ni-based NPs and of their catalysis of VACNF growth. We have shown that ligands encapsulating Ni NPs have a critical role in preventing the NPs from agglomerating during the growth of VACNFs, giving a monodisperse VACNF diameter distribution. The ligands were converted into protective graphitic shells, but if the ligands are intentionally removed after deposition onto the substrate but before initiating VACNF growth, then a polydisperse VACNF diameter distribution are obtained, with a larger average diameter. We have also demonstrated VACNF growth on several metal substrates, where addition of Si micropowder allows the growth of Si-enriched coatings that make the VACNFs mechanically rigid. Recommendations for ongoing research include investigating the conversion chemistry of Ni NPs into nickel chalcogenides or other transition bimetallic NPs and to explore application for nanomaterials in catalysis, plasmonics, electronics, and medicine.

  14. Comparative thermal stability characteristics and isothermal oxidation behavior of an aluminized and a Pt-aluminized Ni-base superalloy

    SciTech Connect

    Tawancy, H.M.; Sridhar, N.; Abbas, N.M.; Rickerby, D.

    1995-11-01

    It is the objective of this paper to compare the thermal stability characteristics and isothermal oxidation behavior of an aluminide coating and a Pt-aluminide coating of the same Al content on a Ni-base superalloy. Addition of Pt to an aluminide coating was found to improve its thermal stability as well as its capability for selective oxidation of Al resulting in a purer scale of slower growth rate. This was correlated with the greater diffusional stability of the Pt-aluminide coating restricting the transport of substrate elements into the outer coating layers.

  15. Reduced Dwell-Fatigue Resistance in a Ni-Base Superalloy After Short-Term Thermal Exposure

    NASA Astrophysics Data System (ADS)

    Hörnqvist, Magnus; Viskari, Leif

    2014-06-01

    The effect of short-term thermal exposure on microstructure and dwell-fatigue resistance of Ni-base superalloy 718Plus was investigated. Contrary to previous studies performed after long-term exposure, an increase in the dwell-fatigue crack growth rate was observed, which was connected to a small increase in the size of the hardening precipitates. The proposed controlling mechanism was the stress relaxation rate at the crack tip, and based on this a schematic model for the development of the properties during exposure is presented.

  16. Antimicrobial Organometallic Dendrimers with Tunable Activity against Multidrug-Resistant Bacteria.

    PubMed

    Abd-El-Aziz, Alaa S; Agatemor, Christian; Etkin, Nola; Overy, David P; Lanteigne, Martin; McQuillan, Katherine; Kerr, Russell G

    2015-11-01

    Multidrug-resistant pathogens are an increasing threat to public health. In an effort to curb the virulence of these pathogens, new antimicrobial agents are sought. Here we report a new class of antimicrobial organometallic dendrimers with tunable activity against multidrug-resistant Gram-positive bacteria that included methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus faecium. Mechanistically, these redox-active, cationic organometallic dendrimers induced oxidative stress on bacteria and also disrupted the microbial cell membrane. The minimum inhibitory concentrations, which provide a quantitative measure of the antimicrobial activity of these dendrimers, were in the low micromolar range. AlamarBlue cell viability assay also confirms the antimicrobial activity of these dendrimers. Interestingly, these dendrimers were noncytotoxic to epidermal cell lines and to mammalian red blood cells, making them potential antimicrobial platforms for topical applications. PMID:26452022

  17. Aromatic Methoxylation and Hydroxylation by Organometallic High-Valent Nickel Complexes.

    PubMed

    Zhou, Wen; Schultz, Jason W; Rath, Nigam P; Mirica, Liviu M

    2015-06-24

    Herein we report the synthesis and reactivity of several organometallic Ni(III) complexes stabilized by a modified tetradentate pyridinophane ligand containing one phenyl group. A room temperature stable dicationic Ni(III)-disolvento complex was also isolated, and the presence of two available cis coordination sites in this complex offers an opportunity to probe the C-heteroatom bond formation reactivity of high-valent Ni centers. Interestingly, the Ni(III)-dihydroxide and Ni(III)-dimethoxide species can be synthesized, and they undergo aryl methoxylation and hydroxylation that is favored by addition of oxidant, which also limits the β-hydride elimination side reaction. Overall, these results provide strong evidence for the involvement of high-valent organometallic Ni species, possibly both Ni(III) and Ni(IV) species, in oxidatively induced C-heteroatom bond formation reactions. PMID:26053329

  18. Writing nanopatterns with electrochemical oxidation on redox responsive organometallic multilayers by AFM

    NASA Astrophysics Data System (ADS)

    Song, Jing; Hempenius, Mark A.; Jing Chung, Hong; Julius Vancso, G.

    2015-05-01

    Nanoelectrochemical patterning of redox responsive organometallic poly(ferrocenylsilane) (PFS) multilayers is demonstrated by electrochemical dip pen lithography (EDPN). Local electrochemical oxidation and Joule heating of PFS multilayers from the tip are considered as relevant mechanisms related to structure generation. The influence of applied bias potential, tip velocity, and multilayer thickness on the pattern height and width were investigated.Nanoelectrochemical patterning of redox responsive organometallic poly(ferrocenylsilane) (PFS) multilayers is demonstrated by electrochemical dip pen lithography (EDPN). Local electrochemical oxidation and Joule heating of PFS multilayers from the tip are considered as relevant mechanisms related to structure generation. The influence of applied bias potential, tip velocity, and multilayer thickness on the pattern height and width were investigated. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr01206f

  19. Energy and chemicals from the selective electrooxidation of renewable diols by organometallic fuel cells.

    PubMed

    Bellini, Marco; Bevilacqua, Manuela; Filippi, Jonathan; Lavacchi, Alessandro; Marchionni, Andrea; Miller, Hamish A; Oberhauser, Werner; Vizza, Francesco; Annen, Samuel P; Grützmacher, H

    2014-09-01

    Organometallic fuel cells catalyze the selective electrooxidation of renewable diols, simultaneously providing high power densities and chemicals of industrial importance. It is shown that the unique organometallic complex [Rh(OTf)(trop2NH)(PPh3)] employed as molecular active site in an anode of an OMFC selectively oxidizes a number of renewable diols, such as ethylene glycol , 1,2-propanediol (1,2-P), 1,3-propanediol (1,3-P), and 1,4-butanediol (1,4-B) to their corresponding mono-carboxylates. The electrochemical performance of this molecular catalyst is discussed, with the aim to achieve cogeneration of electricity and valuable chemicals in a highly selective electrooxidation from diol precursors. PMID:25082272

  20. Molecular Models of Ruthenium(II) Organometallic Complexes

    ERIC Educational Resources Information Center

    Coleman, William F.

    2007-01-01

    This article presents the featured molecules for the month of March, which appear in the paper by Ozerov, Fafard, and Hoffman, and which are related to the study of the reactions of a number of "piano stool" complexes of ruthenium(II). The synthesis of compound 2a offers students an alternative to the preparation of ferrocene if they are only…

  1. Regioselective nucleophilic addition of organometallic reagents to 3-geminal bis(silyl) N-acyl pyridinium.

    PubMed

    Wu, Ya; Li, Linjie; Li, Hongze; Gao, Lu; Xie, Hengmu; Zhang, Zhigao; Su, Zhishan; Hu, Changwei; Song, Zhenlei

    2014-04-01

    A regioselective nucleophilic addition to 3-geminal bis(silyl) N-acyl pyridinium has been described. Geminal bis(silane) shows contrasting roles that lead to different regioselectivities for the addition of different nucleophiles: its steric effect dominates to favor 1,6-addition of alkyl, vinyl, and aryl organometallic reagents; its directing effect dominates to favor 1,2-addition of less sterically demanding alkynyl Grignard reagents. PMID:24666415

  2. Molecular tectonics: heterometallic coordination networks based on a Pt(II) organometallic metallatecton.

    PubMed

    Zigon, Nicolas; Kyritsakas, Nathalie; Hosseini, Mir Wais

    2015-08-28

    Combinations of a neutral organometallic tecton based on a square planar Pt(ii) complex bearing two triphenylphosphine groups and two 4-ethynylpyridyl coordinating moieties in trans positions, with various metal halides (MX2, M = Co(ii), Ni(ii), Cd(ii), X = Cl(-) or Br(-)) lead to the formation of 2D grid type heterobimetallic coordination networks in the crystalline phase. PMID:26204438

  3. Enhancement of Selectivity of an Organometallic Anticancer Agent by Redox Modulation.

    PubMed

    Romero-Canelón, Isolda; Mos, Magdalena; Sadler, Peter J

    2015-10-01

    Combination with redox modulators can potentiate the anticancer activity and maximize the selectivity of organometallic complexes with redox-based mechanisms of action. We show that nontoxic doses of l-buthionine sulfoximine increase the selectivity of organo-Os complex FY26 for human ovarian cancer cells versus normal lung fibroblasts to 63-fold. This increase is not due to changes in the mechanism of action of FY26 but to the decreased response of cancer cells to oxidative stress. PMID:26397305

  4. Progress toward cascade cells made by OM-VPE. [organometallic vapor phase epitaxy

    NASA Technical Reports Server (NTRS)

    Borden, P. G.; Larue, R. A.; Ludowise, M. J.

    1982-01-01

    Organometallic Vapor Phase Epitaxy (COM-VPE) was used to make a sophisticated monolithic cascade cell, with a peak AMO efficiency of 16.6%, not corrected for 14% grid coverage. The cell has 9 epitaxial layers. The top cell is 1.35 microns thick with a 0.1 micron thich emitter. Both cells are heteroface n-p structures. The cascade cell uses metal interconnects. Details of growth and processing are described.

  5. Organometallic Polymer Coatings for Geothermal-Fluid-Sprayed Air-Cooled Condensers: Preprint

    SciTech Connect

    Gawlik, K.; Sugama, T.; Jung, D.

    2002-08-01

    Researchers are developing polymer-based coating systems to reduce scaling and corrosion of air-cooled condensers that use a geothermal fluid spray for heat transfer augmentation. These coating systems act as barriers to corrosion to protect aluminum fins and steel tubing; they are formulated to resist the strong attachment of scale. Field tests have been done to determine the corrosion and scaling issues related to brine spraying and a promising organometallic polymer has been evaluated in salt spray tests.

  6. Enhancement of Selectivity of an Organometallic Anticancer Agent by Redox Modulation

    PubMed Central

    2015-01-01

    Combination with redox modulators can potentiate the anticancer activity and maximize the selectivity of organometallic complexes with redox-based mechanisms of action. We show that nontoxic doses of l-buthionine sulfoximine increase the selectivity of organo-Os complex FY26 for human ovarian cancer cells versus normal lung fibroblasts to 63-fold. This increase is not due to changes in the mechanism of action of FY26 but to the decreased response of cancer cells to oxidative stress. PMID:26397305

  7. 2011 Organometallic Chemistry (July 10-15, 2011, Salve Regina University, Newport, RI)

    SciTech Connect

    Dr. Emilio Bunel

    2011-07-15

    Organometallic chemistry has played and will continue to play a significant role in helping us understand the way bonds are made or broken in the presence of a transition metal complex. Current challenges range from the efficient exploitation of energy resources to the creative use of natural and artificial enzymes. Most of the new advances in the area are due to our extended understanding of processes at a molecular level due to new mechanistic studies, techniques to detect reaction intermediates and theory. The conference will bring the most recent advances in the field including nanocatalysis, surface organometallic chemistry, characterization techniques, new chemical reactivity and theoretical approaches along with applications to organic synthesis and the discovery of new materials. The Conference will bring together a collection of investigators who are at the forefront of their field, and will provide opportunities for junior scientists and graduate students to present their work in poster format and exchange ideas with leaders in the field. Six outstanding posters will be selected for short talks. The collegial atmosphere of this Conference, with programmed discussion sessions as well as opportunities for informal gatherings in the afternoons and evenings, provides an avenue for scientists from different disciplines to brainstorm and promotes cross-disciplinary collaborations in the various research areas represented. Graduate students and postdoctoral fellows should also consider participating in the Gordon Research Seminar on Organometallic Chemistry (July 9-10, same location) which is specially designed to promote interaction and discussion between junior scientists.

  8. Electron configuration and correlation effects in organometallic molecules from constraint density functional theory

    NASA Astrophysics Data System (ADS)

    Nawa, Kenji; Nakamura, Kohji; Akiyama, Toru; Ito, Tomonori; Weinert, Michael

    2015-03-01

    Interest in single organometallic molecule and that adsorbed on solid surfaces has rapidly increased because of possible novel applications. For molecules with transition metals (TMs), the d-electron configuration is an essential aspect of their electronic and magnetic properties, and correlation effects can not be excluded. Here, we investigate systematically the electron configuration and correlation effects for prototypical organometallic molecules of tridimensional metallocene (TMCp2) and planer phthalocyanine (TMPc). Calculations were carried out based on the constraint density functional theory (DFT) by using the full-potential linearized augmented plane wave method that incorporates an on-site Coulomb interaction correction + U . We find that these correlation effects play a key role in determining the ground state of the electron configuration for the organometallic molecules. The calculated ground states of TMCp2, where TM =Cr, Mn, Fe, Co, and Ni, obtained by constraint DFT with +U reproduce the experimentally determined structures of 3E2 g , 6A1 g , 1A1 g , 2E1 g , and 3A2 g , respectively. Results for the TMPc will be also presented.

  9. Amphiphilic nanocapsules entangled with organometallic coordination polymers for controlled cargo release.

    PubMed

    Liang, Guodong; Ni, Huan; Bao, Suping; Zhu, Fangming; Gao, Haiyang; Wu, Qing; Tang, Ben Zhong

    2014-06-01

    A class of new amphiphilic nanocapsules entangled with organometallic coordination polymers has been developed for the first time. Poly(2-(N,N-dimethyl amino)ethyl methacrylate)-b-polystyrene capped with β-cyclodextrin (β-CD) (CD-PDMAEMA-b-PS) is first synthesized using sequent RAFT polymerization of styrene and 2-(N,N-dimethyl amino)ethyl methacrylate with xanthate modified β-CD as chain transfer agent. The end group of β-CD is allowed to include 4,4'-bipyridine through host-guest inclusion to yield PDMAEMA-b-PS terminated with an inclusion complex of β-CD and bipyridine (bpy-PDMAEMA-b-PS), which is then used as surfactant to prepare emulsion droplets in toluene/water mixture. Upon addition of Ni(II), bipyridine coordinates with Ni(II) to form coordination polymers in the periphery of emulsion droplets, affording amphiphilic capsules entangled with organometallic coordination polymers, as confirmed by GPC, (1)H NMR, SEM, TEM, DLS, and so on. The organometallic coordination polymer capsules are capable of encapsulating organic cargoes. Interestingly, encapsulated cargoes can be extracted from the capsules without damaging the capsules. Such capsules are potential candidates for encapsulating and controlled release of organic cargoes. PMID:24828951

  10. Synthesis of Some "Cobaloxime" Derivatives: A Demonstration of "Umpolung" in the Reactivity of an Organometallic Complex

    NASA Astrophysics Data System (ADS)

    Jameson, Donald L.; Grzybowski, Joseph J.; Hammels, Deb E.; Castellano, Ronald K.; Hoke, Molly E.; Freed, Kimberly; Basquill, Sean; Mendel, Angela; Shoemaker, William J.

    1998-04-01

    This article describes a four-reaction sequence for the synthesis of two organometallic "cobaloxime" derivatives. The concept of "Umpolung" or reversal of reactivity is demonstrated in the preparation of complexes. The complex Co(dmgH)2(4-t-BuPy)Et is formed by the reaction of a cobalt (I) intermediate (cobalt in the role of nucleophile) with ethyl iodide. The complex Co(dmgH)2(4-t-BuPy)Ph is formed by the reaction of PhMgBr with a cobalt (III) intermediate (cobalt in the role of electrophile). All the products contain cobalt in the diamagnetic +3 oxidation state and are readily characterized by proton and carbon NMR. The four reaction sequence may be completed in two 4-hour lab periods. Cobaloximes are well known as model complexes for Vitamin B-12 and the experiment exposes students to aspects of classical coordination chemistry, organometallic chemistry and bioinorganic chemistry. The experiment also illustrates an important reactivity parallel between organic and organometallic chemistry.

  11. Investigation of organometallic reaction mechanisms with one and two dimensional vibrational spectroscopy

    SciTech Connect

    Cahoon, James Francis

    2008-12-01

    One and two dimensional time-resolved vibrational spectroscopy has been used to investigate the elementary reactions of several prototypical organometallic complexes in room temperature solution. The electron transfer and ligand substitution reactions of photogenerated 17-electron organometallic radicals CpW(CO)3 and CpFe(CO)2 have been examined with one dimensional spectroscopy on the picosecond through microsecond time-scales, revealing the importance of caging effects and odd-electron intermediates in these reactions. Similarly, an investigation of the photophysics of the simple Fischer carbene complex Cr(CO)5[CMe(OMe)] showed that this class of molecule undergoes an unusual molecular rearrangement on the picosecond time-scale, briefly forming a metal-ketene complex. Although time-resolved spectroscopy has long been used for these types of photoinitiated reactions, the advent of two dimensional vibrational spectroscopy (2D-IR) opens the possibility to examine the ultrafast dynamics of molecules under thermal equilibrium conditions. Using this method, the picosecond fluxional rearrangements of the model metal carbonyl Fe(CO)5 have been examined, revealing the mechanism, time-scale, and transition state of the fluxional reaction. The success of this experiment demonstrates that 2D-IR is a powerful technique to examine the thermally-driven, ultrafast rearrangements of organometallic molecules in solution.

  12. Assessing the Effects of Radiation Damage on Ni-base Alloys for the Prometheus Space Reactor System

    SciTech Connect

    T. Angeliu

    2006-01-19

    Ni-base alloys were considered for the Prometheus space reactor pressure vessel with operational parameters of {approx}900 K for 15 years and fluences up to 160 x 10{sup 20} n/cm{sup 2} (E > 0.1 MeV). This paper reviews the effects of irradiation on the behavior of Ni-base alloys and shows that radiation-induced swelling and creep are minor considerations compared to significant embrittlement with neutron ,exposure. While the mechanism responsible for radiation-induced embrittlement is not fully understood, it is likely a combination of helium embrittlement and solute segregation that can be highly dependent on the alloy composition and exposure conditions. Transmutation calculations show that detrimental helium levels would be expected at the end of life for the inner safety rod vessel (thimble) and possibly the outer pressure vessel, primarily from high energy (E > 1 MeV) n,{alpha} reactions with {sup 58}Ni. Helium from {sup 10}B is significant only for the outer vessel due to the proximity of the outer vessel to the Be0 control elements. Recommendations for further assessments of the material behavior and methods to minimize the effects of radiation damage through alloy design are provided.

  13. Microstructure chemistry and mechanical properties of Ni-based superalloy Rene N4 under irradiation at room temperature

    SciTech Connect

    Sun, C.; Kirk, M.; Li, M.; Hattar, Khalid Mikhiel; Wang, Y.; Anderoglu, O.; Valdez, J.; Uberuaga, B. P.; Dickerson, R.; Maloy, S. A.

    2015-06-14

    Nickel superalloys with cubic L12 structured γ' (Ni3(Al, Ti)) precipitates exhibit high strength at high temperatures and excellent corrosion resistance when exposed to water. Unlike prior studies on irradiation damage of other Ni-based superalloys, our study on Rene N4 involves much larger γ' precipitates, ~450 nm in size, a size regime where the irradiation-induced disordering and dissolution kinetics and the corresponding mechanical property evolution are unknown. Under heavy ion irradiation at room temperature, the submicron-sized γ' precipitates were fully disordered at ~0.3 dpa and only later partially dissolved after 75 dpa irradiation. Nanoindentation experiments indicate that the mechanical properties of the alloy change significantly, with a dramatic decrease in hardness, with irradiation dose. Three contributions to the change in hardness were examined: defect clusters, disordering and dissolution. Moreover, the generation of defect clusters in the matrix and precipitates slightly increased the indentation hardness, while disordering of the submicron-sized γ' precipitates resulted in a dramatic decrease in the total hardness, which decreased further during the early stages of the intermixing between γ' precipitates and matrix (<18 dpa). As a result, controlling the long-range-ordering and chemical intermixing can be used to tailor the mechanical properties of Ni-based superalloys under irradiation.

  14. New Constitutive Model for Hot Deformation Behaviors of Ni-Based Superalloy Considering the Effects of Initial δ Phase

    NASA Astrophysics Data System (ADS)

    Lin, Y. C.; He, Min; Zhou, Mi; Wen, Dong-Xu; Chen, Jian

    2015-09-01

    The hot deformation behaviors of a typical Ni-based superalloy are investigated by uniaxial tensile tests over wide ranges of strain rate and deformation temperature. The experimental results show that the flow stress is sensitive to strain, strain rate, and deformation temperature. Especially, initial δ phase (Ni3Nb) has a special effect on the flow stress. The initial δ phase can enhance the work-hardening behavior and result in the increased peak stress at relatively small strains. With the further straining, the initial δ phase can stimulate the dynamic recrystallization and promote the dynamic-softening behaviors. Considering the synthetical effects of deformation temperature, strain, strain rate, and initial δ phase on the hot deformation behaviors, a new phenomenological constitutive model is proposed. In the proposed model, the peak stress and material constant are expressed as functions of Zener-Hollomon parameter and the initial content of δ phase. A good agreement between the predicted and measured results shows that the proposed model can give an accurate and precise estimate of the hot deformation behaviors for the studied Ni-based superalloy.

  15. Assessing the Effects of Radiation Damage on Ni-base Alloys for the Prometheus Space Reactor System

    SciTech Connect

    T Angeliu; J Ward; J Witter

    2006-04-04

    Ni-base alloys were considered for the Prometheus space reactor pressure vessel with operational parameters of {approx}900 K for 15 years and fluences up to 160 x 10{sup 20} n/cm{sup 2} (E > 0.1 MeV). This paper reviews the effects of irradiation on the behavior of Ni-base alloys and shows that radiation-induced swelling and creep are minor considerations compared to significant embrittlement with neutron exposure. While the mechanism responsible for radiation-induced embrittlement is not fully understood, it is likely a combination of helium embrittlement and solute segregation that can be highly dependent on the alloy composition and exposure conditions. Transmutation calculations show that detrimental helium levels would be expected at the end of life for the inner safety rod vessel (thimble) and possibly the outer pressure vessel, primarily from high energy (E > 1 MeV) n,{alpha} reactions with {sup 58}Ni. Helium from {sup 10}B is significant only for the outer vessel due to the proximity of the outer vessel to the BeO control elements. Recommendations for further assessments of the material behavior and methods to minimize the effects of radiation damage through alloy design are provided.

  16. Selectivity of Ni-based surface alloys toward hydrazine adsorption: A DFT study with van der Waals interactions

    NASA Astrophysics Data System (ADS)

    He, Yan-Bin; Jia, Jian-Feng; Wu, Hai-Shun

    2015-06-01

    We use dispersion corrected DFT calculations (DFT + D3) to investigate the selectivity of Ni-based surface alloys toward hydrazine adsorption. A series of Ni-M (M = Fe, Pt, Ir, Pd and Rh) alloy films were investigated, namely Ni15/M1/Ni(1 1 1), Ni14/M2/Ni(1 1 1), Ni12/M4/Ni(1 1 1) and Ni8/M8/Ni(1 1 1). Our results show that the doped atoms of Ir, Rh and Fe provide stronger adsorption sites than the Ni atom on the Ni(1 1 1) surface, while the doped atoms of Pt and Pd provide weaker adsorption sites. By analyzing the most favorable adsorption of hydrazine on Ni-M alloy surfaces we found that Ni8Fe8/Ni(1 1 1), Ni8Rh8/Ni(1 1 1), Ni15Ir1/Ni(1 1 1) and Ni14Ir2/Ni(1 1 1) present enhanced adsorption properties if compared to the pure Ni(1 1 1) surface, and seem to be better candidates for hydrazine catalysis, which are in agreement with that found by experiments. The correlation between d-band center position and adsorption energies of top modes in the Ni or doped atom has been calculated at DFT + D3 level to provide further insight into the Ni-based surface alloy properties for hydrazine adsorption.

  17. Microstructure chemistry and mechanical properties of Ni-based superalloy Rene N4 under irradiation at room temperature

    DOE PAGESBeta

    Sun, C.; Kirk, M.; Li, M.; Hattar, Khalid Mikhiel; Wang, Y.; Anderoglu, O.; Valdez, J.; Uberuaga, B. P.; Dickerson, R.; Maloy, S. A.

    2015-06-14

    Nickel superalloys with cubic L12 structured γ' (Ni3(Al, Ti)) precipitates exhibit high strength at high temperatures and excellent corrosion resistance when exposed to water. Unlike prior studies on irradiation damage of other Ni-based superalloys, our study on Rene N4 involves much larger γ' precipitates, ~450 nm in size, a size regime where the irradiation-induced disordering and dissolution kinetics and the corresponding mechanical property evolution are unknown. Under heavy ion irradiation at room temperature, the submicron-sized γ' precipitates were fully disordered at ~0.3 dpa and only later partially dissolved after 75 dpa irradiation. Nanoindentation experiments indicate that the mechanical properties ofmore » the alloy change significantly, with a dramatic decrease in hardness, with irradiation dose. Three contributions to the change in hardness were examined: defect clusters, disordering and dissolution. Moreover, the generation of defect clusters in the matrix and precipitates slightly increased the indentation hardness, while disordering of the submicron-sized γ' precipitates resulted in a dramatic decrease in the total hardness, which decreased further during the early stages of the intermixing between γ' precipitates and matrix (<18 dpa). As a result, controlling the long-range-ordering and chemical intermixing can be used to tailor the mechanical properties of Ni-based superalloys under irradiation.« less

  18. Dislocation decorrelation and relationship to deformation microtwins during creep of a y' precipitate strengthened Ni-based superalloy

    SciTech Connect

    Unocic, R. R.; Zhou, N.; Kovarik, Libor; Shen, C.; Wang, Y.; Mills, M. J.

    2011-11-01

    The evolution of microtwins during high temperature creep deformation in a strengthened Ni-base superalloy has been investigated through a combination of creep testing, TEM characterization, theoretical modeling and computer simulation. Experimentally, microtwin nucleation sources were identified and their evolution was tracked by characterizing the deformation substructure at different stages of the creep deformation. Initially, deformation is highly localized around stress concentrators such as carbides, borides and serrated grain boundaries, which act as sources of a/2<110> matrix type dislocations. Due to microstructural effects such as fine channels between particles and low matrix stacking fault energies, the a/2<110> matrix dislocations dissociate into a/6<112> Shockley partials, which were commonly observed to be decorrelated from one another, creating extended intrinsic stacking faults in the matrix. As deformation progress further, microtwins form via partial dislocations cooperatively shearing both and phases on adjacent {111} glide planes. The TEM observations lead directly to an analysis of dislocation-precipitate interactions. Through phase field simulations and theoretical analysis based on Orowan looping, the important processes of dislocation dissociation and decorrelation are modeled in detail, providing comprehensive insight into the microstructural features and applied stress conditions that favor the microtwinning deformation mode in strengthened Ni-based superalloys.

  19. Dislocation decorrelation and relationship to deformation microtwins during creep of a precipitate strengthened Ni-based superalloy

    SciTech Connect

    Unocic, Raymond R; Zhou, Ning; Kovarik, Libor; Shen, Chen; Wang, Yunzhi; Mills, Michael J.

    2011-01-01

    The evolution of microtwins during high temperature creep deformation in a strengthened Ni-base superalloy has been investigated through a combination of creep testing, transmission electron microscopy (TEM), theoretical modeling, and computer simulation. Experimentally, microtwin nucleation sources were identified and their evolution was tracked by characterizing the deformation substructure at different stages of creep deformation. Deformation is highly localized around stress concentrators such as carbides, borides and serrated grain boundaries, which act as sources of a/2<110> matrix-type dislocations. Due to fine channels between particles, coupled with the low matrix stacking fault energy, the a/2<110> matrix dislocations dissociate into a/6<112> Shockley partials, which were commonly observed to be decorrelated from one another, creating extended intrinsic stacking faults in the matrix. Microtwins are common and form via Shockley partial dislocations cooperatively shearing both and phases on adjacent {111} glide planes. The TEM observations lead directly to an analysis of dislocation-precipitate interactions. Through phase field simulations and theoretical analyses based on Orowan looping, the important processes of dislocation dissociation and decorrelation are modeled in detail, providing comprehensive insight into the microstructural features and applied stress conditions that favor the microtwinning deformation mode in strengthened Ni-based superalloys.

  20. Intercalation compounds involving inorganic layered structures

    PubMed

    Constantino; Barbosa; Bizeto; Dias

    2000-01-01

    Two-dimensional inorganic networks can shown intracrystalline reactivity, i.e., simple ions, large species as Keggin ions, organic species, coordination compounds or organometallics can be incorporated in the interlayer region. The host-guest interaction usually causes changes in their chemical, catalytic, electronic and optical properties. The isolation of materials with interesting properties and making use of soft chemistry routes have given rise the possibility of industrial and technological applications of these compounds. We have been using several synthetic approaches to intercalate porphyrins and phthalocyanines into inorganic materials: smectite clays, layered double hydroxides and layered niobates. The isolated materials have been characterized by elemental and thermal analysis, X-ray diffraction, surface area measurements, scanning electronic microscopy, electronic and resonance Raman spectroscopies and EPR. The degree of layer stacking and the charge density of the matrices as well their acid-base nature were considered in our studies on the interaction between the macrocycles and inorganic hosts. PMID:10932103

  1. The role of the substrate structure in the on-surface synthesis of organometallic and covalent oligophenylene chains.

    PubMed

    Dai, Jingya; Fan, Qitang; Wang, Tao; Kuttner, Julian; Hilt, Gerhard; Gottfried, J Michael; Zhu, Junfa

    2016-07-27

    The influences of the substrate structure on the formation of one-dimensional organometallic and covalent oligomers on a Cu(110) surface were studied using scanning tunneling microscopy (STM), X-ray photoemission spectroscopy (XPS), and low energy electron diffraction (LEED) in ultrahigh vacuum (UHV). Vapor deposition of submonolayer 4,4''-dibromo-meta-terphenyl (DMTP) onto a Cu(110) surface at 300 K leads to scission of C-Br bonds and the formation of organometallic chains (cis/trans and all-trans) connected by C-Cu-C bonds. Larger islands (120 × 120 nm(2)) of all-trans zigzag organometallic chains as sole products were obtained by the deposition of DMTP onto Cu(110) held at 383 K. The domains are oriented along two directions with an angle of ±13° relative to the [0 0 1] direction due to the two-fold symmetry of the Cu(110) surface lattice. This study reveals at a sub-molecular level that the organometallic chains firstly lose copper atoms and then undergo C-C coupling into oligophenylene chains at a substrate temperature around 417 K. Annealing the large islands of organometallic chains at 458 K results in the formation of completely C-C covalently bonded zigzag oligophenylene chains. The zigzag angle of 125° slightly deviates from the ideal value of 120°. This is attributed to a stretching of the zigzag oligophenylene chains due to substrate template effects. PMID:27411742

  2. Organometallic rotaxane dendrimers with fourth-generation mechanically interlocked branches

    PubMed Central

    Wang, Wei; Chen, Li-Jun; Wang, Xu-Qing; Sun, Bin; Li, Xiaopeng; Zhang, Yanyan; Shi, Jiameng; Yu, Yihua; Zhang, Li; Liu, Minghua; Yang, Hai-Bo

    2015-01-01

    Mechanically interlocked molecules, such as catenanes, rotaxanes, and knots, have applications in information storage, switching devices, and chemical catalysis. Rotaxanes are dumbbell-shaped molecules that are threaded through a large ring, and the relative motion of the two components along each other can respond to external stimuli. Multiple rotaxane units can amplify responsiveness, and repetitively branched molecules—dendrimers—can serve as vehicles for assembly of many rotaxanes on single, monodisperse compounds. Here, we report the synthesis of higher-generation rotaxane dendrimers by a divergent approach. Linkages were introduced as spacer elements to reduce crowding and to facilitate rotaxane motion, even at the congested periphery of the compounds up to the fourth generation. The structures were characterized by 1D multinuclear (1H, 13C, and 31P) and 2D NMR spectroscopy, MALDI-TOF-MS, gel permeation chromatography (GPC), and microscopy-based methods including atomic force microscopy (AFM) and transmission electron microscopy (TEM). AFM and TEM studies of rotaxane dendrimers vs. model dendrimers show that the rotaxane units enhance the rigidity and reduce the tendency of these assemblies to collapse by self-folding. Surface functionalization of the dendrimers with ferrocenes as termini produced electrochemically active assemblies. The preparation of dendrimers with a well-defined topological structure, enhanced rigidity, and diverse functional groups opens previously unidentified avenues for the application of these materials in molecular electronics and materials science. PMID:25902491

  3. Organometallic rotaxane dendrimers with fourth-generation mechanically interlocked branches.

    PubMed

    Wang, Wei; Chen, Li-Jun; Wang, Xu-Qing; Sun, Bin; Li, Xiaopeng; Zhang, Yanyan; Shi, Jiameng; Yu, Yihua; Zhang, Li; Liu, Minghua; Yang, Hai-Bo

    2015-05-01

    Mechanically interlocked molecules, such as catenanes, rotaxanes, and knots, have applications in information storage, switching devices, and chemical catalysis. Rotaxanes are dumbbell-shaped molecules that are threaded through a large ring, and the relative motion of the two components along each other can respond to external stimuli. Multiple rotaxane units can amplify responsiveness, and repetitively branched molecules--dendrimers--can serve as vehicles for assembly of many rotaxanes on single, monodisperse compounds. Here, we report the synthesis of higher-generation rotaxane dendrimers by a divergent approach. Linkages were introduced as spacer elements to reduce crowding and to facilitate rotaxane motion, even at the congested periphery of the compounds up to the fourth generation. The structures were characterized by 1D multinuclear ((1)H, (13)C, and (31)P) and 2D NMR spectroscopy, MALDI-TOF-MS, gel permeation chromatography (GPC), and microscopy-based methods including atomic force microscopy (AFM) and transmission electron microscopy (TEM). AFM and TEM studies of rotaxane dendrimers vs. model dendrimers show that the rotaxane units enhance the rigidity and reduce the tendency of these assemblies to collapse by self-folding. Surface functionalization of the dendrimers with ferrocenes as termini produced electrochemically active assemblies. The preparation of dendrimers with a well-defined topological structure, enhanced rigidity, and diverse functional groups opens previously unidentified avenues for the application of these materials in molecular electronics and materials science. PMID:25902491

  4. A neutral organometallic fluoro complex can be a good ligand.

    PubMed

    Coue, Laurent; Cuesta, Luciano; Morales, Dolores; Halfen, Jason A; Pérez, Julio; Riera, Lucía; Riera, Víctor; Miguel, Daniel; Connelly, Neil G; Boonyuen, Supakorn

    2004-04-19

    The reaction of the complex [Mo(OTf)(eta(3)-C(3)H(4)-Me-2)(CO)(2)(phen)] (1) (OTf = trifluoromethylsulfonate; phen = 1,10-phenanthroline) with tetrabutylammonium fluoride trihydrate afforded the fluoride complex [MoF(eta(3)-C(3)H(4)-Me-2)(CO)(2)(phen)] (2). The IR spectrum and the oxidation potential of 2 reflect the fact that its metal center is more electron-rich than that of the chloro analogue [MoCl(eta(3)-C(3)H(4)-Me-2)(CO)(2)(phen)]. Compound 2 reacted with 1 affording the homobinuclear complex [[Mo(eta(3)-C(3)H(4)-Me-2)(CO)(2)(phen)](2)(mu-F)][OTf] (3), with a fluoride bridge. Compound 2 also reacts with the species generated in situ by triflate abstraction from [M(OTf)(CO)(3)('N-N')] (M = Mn, Re; 'N-N' = 2,2'-bipyridine (bipy), phen) using NaBAr'(4) (Ar' = 3,5-bis(trifluoromethyl)phenyl), affording the heterobinuclear complexes [[Mo(eta(3)-C(3)H(4)-Me-2)(CO)(2)(phen)](mu-F)[M(CO)(3)('N--N')

  5. An Advanced Organometallic Lab Experiment with Biological Implications: Synthesis and Characterization of Fe[subscript 2](µ-S[subscript 2])(C0)[subscript 6

    ERIC Educational Resources Information Center

    Barrett, Jacob; Spentzos, Ariana; Works, Carmen

    2015-01-01

    The organometallic complex Fe[subscript 2](µ-S[subscript 2])(CO)[subscript 6] has interesting biological implications. The concepts of bio-organometallic chemistry are rarely discussed at the undergraduate level, but this experiment can start such a conversation and, in addition, teach valuable synthetic techniques. The lab experiment takes a…

  6. 10,000-Hour Cyclic Oxidation Behavior at 982 C (1800 F) of 68 High-Temperature Co-, Fe-, and Ni-Base Alloys

    NASA Technical Reports Server (NTRS)

    Barrett, Charles A.

    1997-01-01

    Sixty-eight high temperature Co-, Fe-, and Ni-base alloys were tested for 10-one thousand hour cycles in static air at 982 C (1800 F). The oxidation behavior of the test samples was evaluated by specific weight change/time data, x-ray diffraction of the post-test samples, and their final appearance. The gravimetric and appearance data were combined into a single modified oxidation parameter, KB4 to rank the cyclic oxidation resistance from excellent to catastrophic. The alloys showing the 'best' resistance with no significant oxidation attack were the alumina/aluminate spinel forming Ni-base turbine alloys: U-700, NASA-VIA and B-1900; the Fe-base ferritic alloys with Al: TRW-Valve, HOS-875, NASA-18T, Thermenol and 18SR; and the Ni-base superalloy IN-702.

  7. Interdiffusion behavior between NiAlHf coating and Ni-based single crystal superalloy with different crystal orientations

    NASA Astrophysics Data System (ADS)

    Wang, Ruili; Gong, Xueyuan; Peng, Hui; Ma, Yue; Guo, Hongbo

    2015-01-01

    NiAlHf coatings were deposited onto Ni-based single crystal (SC) superalloy with different crystal orientations by electron beam physical vapor deposition (EB-PVD). The effects of the crystal orientations of the superalloy substrate on inter-diffusion behavior between the substrate and the NiAlHf coating were investigated. Substrate diffusion zone (SDZ) containing needle-like μ phases and interdiffusion zone (IDZ) mainly consisting of the ellipsoidal and rod-like μ phases were formed in the SC alloy after heat-treatment 10 h at 1100 °C. The thickness of secondary reaction zone (SRZ) formed in the SC alloy with (0 1 1) crystal orientation is about 14 μm after 50 h heat-treatment at 1100 °C, which is relatively thicker than that in the SC alloy with (0 0 1) crystal orientation, whereas the IDZ revealed similar thickness.

  8. Fabrication of High-Pressure Cold-Sprayed Coating on Ni-Based Superalloy for High-Temperature Corrosive Conditions

    NASA Astrophysics Data System (ADS)

    Singh, Harminder

    2015-11-01

    The surface behavior of the Ni-based superalloy (composition similar to UNS N06075) is altered in this study by depositing a 298- µm-thick coating for various erosive-corrosive and wear applications at a high temperature. The 50%Ni-50%Cr coating was developed by a high-pressure cold-spraying method. The coating microstructure was studied by various characterization techniques. The unmelted solid particles formed the coating structure, which is homogeneous, dense, hard, and free from cracks, oxides, and other defects. The coating composition and microstructure is suitable for providing protection to the substrate under high-temperature corrosive conditions. The developed coating performed well, with degradation rate of 0.47 mm/year, in the chlorine-based highly corrosive conditions of actual waste incinerator at 900°C.

  9. V-Notched Bar Creep Life Prediction: GH3536 Ni-Based Superalloy Under Multiaxial Stress State

    NASA Astrophysics Data System (ADS)

    Zhang, D. X.; Wang, J. P.; Wen, Z. X.; Liu, D. S.; Yue, Z. F.

    2016-07-01

    In this study, creep experiments on smooth and circumferential V-type notched round bars were conducted in GH3536 Ni-based superalloy at 750 °C to identify notch strengthening effect in notched specimens. FE analysis was carried out, coupled with continuum damage mechanics (CDM), to analyze stress distribution and damage evolution under multiaxial stress state. The creep deformation of smooth specimens and the rupture life of both smooth and notched specimens showed good agreement between experimental results and FE analysis predictions; the creep rupture life for the notched specimen was successfully predicted via the "skeletal point" concept. Both creep damage analysis and the observed fracture morphology suggest that creep rupture started first at the root in the V-type notched specimens, and shifted to the region close to the notch root when the notch was relatively shallow compared to U-type notched specimens.

  10. V-Notched Bar Creep Life Prediction: GH3536 Ni-Based Superalloy Under Multiaxial Stress State

    NASA Astrophysics Data System (ADS)

    Zhang, D. X.; Wang, J. P.; Wen, Z. X.; Liu, D. S.; Yue, Z. F.

    2016-05-01

    In this study, creep experiments on smooth and circumferential V-type notched round bars were conducted in GH3536 Ni-based superalloy at 750 °C to identify notch strengthening effect in notched specimens. FE analysis was carried out, coupled with continuum damage mechanics (CDM), to analyze stress distribution and damage evolution under multiaxial stress state. The creep deformation of smooth specimens and the rupture life of both smooth and notched specimens showed good agreement between experimental results and FE analysis predictions; the creep rupture life for the notched specimen was successfully predicted via the "skeletal point" concept. Both creep damage analysis and the observed fracture morphology suggest that creep rupture started first at the root in the V-type notched specimens, and shifted to the region close to the notch root when the notch was relatively shallow compared to U-type notched specimens.

  11. Swift heavy ion induced surface modification for tailoring coercivity in Fe-Ni based amorphous thin films

    SciTech Connect

    Thomas, Senoy; Thomas, Hysen; Anantharaman, M. R.; Avasthi, D. K.; Tripathi, A.; Ramanujan, R. V.

    2009-02-01

    Fe-Ni based amorphous thin films were prepared by thermal evaporation. These films were irradiated by 108 MeV Ag{sup 8+} ions at room temperature with fluences ranging from 1x10{sup 12} to 3x10{sup 13} ions/cm{sup 2} using a 15 UD Pelletron accelerator. Glancing angle x-ray diffraction studies showed that the irradiated films retain their amorphous nature. The topographical evolution of the films under swift heavy ion (SHI) bombardment was probed using atomic force microscope and it was noticed that surface roughening was taking place with ion beam irradiation. Magnetic measurements using a vibrating sample magnetometer showed that the coercivity of the films increases with an increase in the ion fluence. The observed coercivity changes are correlated with topographical evolution of the films under SHI irradiation. The ability to modify the magnetic properties via SHI irradiation could be utilized for applications in thin film magnetism.

  12. A synchrotron study of defect and strain inhomogeneity in laser-assisted three-dimensionally-printed Ni-based superalloy

    NASA Astrophysics Data System (ADS)

    Li, Yao; Qian, Dan; Xue, Jiawei; Wan, Jingchun; Zhang, Anfeng; Tamura, Nobumichi; Song, Zhongxiao; Chen, Kai

    2015-11-01

    Synchrotron X-ray microdiffraction was employed to investigate the inhomogeneous distribution of defect and residual strain in the transitional region between the dendritic and stray grains in a laser-assisted 3D printed Ni-based superalloy. The dendritic region was found to be under tensile strain transversely to the primary dendrite arm directions. The dendrite edges, where high level of strains and geometrically necessary dislocations were detected, were discerned as low angle grain boundaries. High angle grain boundaries were observed in the stray grain region, and the orientation of the strain tensor in this region varied dramatically at the micron scale, in contrast with the more or less homogeneous distribution in the dendritic region.

  13. X-ray Microdiffraction and EBSD Study of FSP Induced Structural/Phase Transitions in a Ni-based Superalloy

    SciTech Connect

    Barabash, Oleg M; Barabash, Rozaliya; Ice, Gene E; Feng, Zhili; Gandy, Dr. David

    2009-01-01

    Severe plastic deformation during Friction Stir Processing (FSP) of an IN738 Ni-based superalloy was studied by means of X-ray polychromatic microdiffraction, EBSD, scanning electron and optical microscopies. Modeling of the physical properties and phase composition was also performed. Several distinct zones are formed during FSP including a stir zone (SZ), a thermal-mechanical affected zone (TMAZ) and a heat affected zone (HAZ). Each zone has distinct microstructure after FSP. The initial dendrite structure is preserved in the HAZ, while strengthening ??-phase particles partially dissolve and coagulate. Plastic deformation of the base material dendrites takes place in the TMAZ and a large number of geometrically necessary dislocations are formed. The extent of deformation increases toward the SZ and the dendrite structure is completely destroyed in the SZ and replaced by a fine submicrocrystalline microstructure.

  14. Effect of oxygen content and heat treatment on carbide precipitation behavior in PM Ni-base superalloys

    NASA Astrophysics Data System (ADS)

    Liu, Heng-san; Zhang, Lin; He, Xin-bo; Qu, Xuan-hui; Zhu, Hong-min; Zhang, Guo-qing

    2012-09-01

    The influence of oxygen content and heat treatment on the evolution of carbides in a powder metallurgy (PM) Ni-base superalloy was characterized. The results reveal that oxygen content has little influence on the precipitation of carbides inside the particles. However, under the consolidated state, stable Ti oxides on the particle surface act as nuclei for the precipitation of prior particle boundaries (PPB). Also, oxygen can diffuse internally along grain boundaries under compressive stress, which favors the precipitation of carbides inside the particles. Therefore, a higher amount of carbides will appear with more oxygen content in the case of consolidated alloys. It is also observed that PPB can be disrupted into discontinuous particles at 1200°C, but this carbide network is hard to be eliminated completely. The combined MC-M23C6 morphology approves the nucleation and growth mechanism of carbide evolution.

  15. The wetting characteristics and surface tension of some Ni-based alloys on yttria, hafnia, alumina, and zirconia substrates

    NASA Technical Reports Server (NTRS)

    Kanetkar, C. S.; Kacar, A. S.; Stefanescu, D. M.

    1988-01-01

    The surface tension and wetting characteristics of four commercial Ni-based alloys (UD718, Waspaloy, UD720, and UD520), pure Ni, and three special alloys (Ni-20 percent Cr, Ni-20 percent Cr-1 percent Al, and Ni-20 percent Cr-4 percent Al) on various ceramic substrates (including alumina, zirconia, hafnia, and yttria) were investigated using sessile drop experiments. Most of the systems studied exhibited a nonwetting behavior. Wetting improved with holding time at a given temperature to the point that some systems, such as Ni-20Cr on alumina, Ni-20Cr-4Al on alumina and on yttria, became marginally wetting. Wetting characteristics were apparently related to constitutional undercooling, which in turn could be affected by the metal dissolving some of the substrate during measurements.

  16. Microsegregation and Secondary Phase Formation During Directional Solidification of the Single-Crystal Ni-Based Superalloy LEK94

    NASA Astrophysics Data System (ADS)

    Lopez-Galilea, Inmaculada; Huth, Stephan; Fries, Suzana G.; Warnken, Nils; Steinbach, Ingo; Theisen, Werner

    2012-12-01

    A multicomponent phase-field method coupled to thermodynamic calculations according to the CALPHAD method was used to simulate microstructural evolution during directional solidification of the LEK94 commercial single-crystal Ni-based superalloy using a two-dimensional unit cell approximation. We demonstrate quantitative agreement of calculated microsegregation profiles and profiles determined from casting experiments as well as calculated fraction solid curves with those determined in differential thermal analysis (DTA) measurements. Finally, the role of solidification rate on dendrite morphology and precipitation of the secondary phases is investigated and a new measure of the dendrite morphology is presented to quantify the effect of back diffusion on the amount of secondary phases.

  17. The Structure-Phase Compositions of Powder Ni - based Coatings after Modification by DC Plasma Jet Irradiation

    NASA Astrophysics Data System (ADS)

    Alontseva, D.; Ghassemieh, E.

    2015-10-01

    This paper presents the results of investigation of the structure-phase compositions of Ni-based coatings deposited by plasma jet on steel substrates after modification by direct current (DC) plasma jet irradiation. Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM) and X-ray Diffraction (XRD) are used in the current study. The phase structures and morphology of precipitation of strengthening phases from solid solution are defined. The irradiation of the coatings leads to the evolution of the structural-phase state of coatings: an increase in the volume fraction of hardening intermetallic phases, the formation of sufficiently homogeneous fine-grained structure in the irradiated coatings. There is a mutual penetration of the substrate main element Fe into the coating and base coating elements Ni into the substrate as a result of the coating treatment by a pulse DC plasma jet.

  18. Regeneration of Sulfur Deactivated Ni-based Biomass Syngas Cleaning Catalysts

    SciTech Connect

    Li, Liyu; Howard, Christopher J.; King, David L.; Gerber, Mark A.; Dagle, Robert A.; Stevens, Don J.

    2010-09-14

    Nickel-based catalysts have been widely tested in decomposing tar and methane in hot biomass syngas cleanup researches. However these catalysts can be easily deactivated by the sulfur compounds in syngas due to the strong sulfur adsorption effect on the Ni surface. Here we report on a new regeneration process, which can effectively and efficiently regenerate the sulfur-poisoned Ni reforming catalysts. This process consists of four sequential treatments: 1) controlled oxidation at 750oC in 1% O2, 2) decomposition at 900oC in Ar, 3) reduction at 900oC in 2% H2, and 4) reaction at 900oC under reforming condition. The duration of this 4-step regeneration process is only about 8 hours, which is shorter than that of the conventional steaming regeneration treatment.

  19. Configurationally Stable, Enantioenriched Organometallic Nucleophiles in Stereospecific Pd-Catalyzed Cross-Coupling Reactions: An Alternative Approach to Asymmetric Synthesis

    PubMed Central

    Wang, Chao-Yuan; Derosaa, Joseph

    2015-01-01

    Several research groups have recently developed methods to employ configurationally stable, enantioenriched organometallic nucleophiles in stereospecific Pd-catalyzed cross-coupling reactions. By establishing the absolute configuration of a chiral alkyltin or alkylboron nucleophile prior to its use in cross-coupling reactions, new stereogenic centers may be rapidly and reliably generated with preservation of the known initial stereochemistry. While this area of research is still in its infancy, such stereospecific cross-coupling reactions may emerge as simple, general methods to access diverse, optically active products from common enantioenriched organometallic building blocks. This minireview highlights recent progress towards the development of general, stereospecific Pd-catalyzed cross-coupling reactions using configurationally stable organometallic nucleophiles. PMID:26388985

  20. Organometallic synthesis, reactivity and catalysis in the solid state using well-defined single-site species

    PubMed Central

    Pike, Sebastian D.; Weller, Andrew S.

    2015-01-01

    Acting as a bridge between the heterogeneous and homogeneous realms, the use of discrete, well-defined, solid-state organometallic complexes for synthesis and catalysis is a remarkably undeveloped field. Here, we present a review of this topic, focusing on describing the key transformations that can be observed at a transition-metal centre, as well as the use of well-defined organometallic complexes in the solid state as catalysts. There is a particular focus upon gas–solid reactivity/catalysis and single-crystal-to-single-crystal transformations. PMID:25666064

  1. Exploration geochemical technique for the determination of preconcentrated organometallic halides by ICP-AES

    USGS Publications Warehouse

    Motooka, J.M.

    1988-01-01

    An atomic absorption extraction technique which is widely used in geochemical exploration for the determination of Ag, As, Au, Bi, Cd, Cu, Mo, Pb, Sb, and Zn has been modified and adapted to a simultaneous inductively coupled plasma-atomic emission instrument. the experimental and operating parameters are described for the preconcentration of the metals into their organometallic halides and for the determination of the metals. Lower limits of determination are equal to or improved over those for flame atomic absorption (except Au) and ICP results are very similar to the accepted AA values, with precision for the ICP data in excess of that necessary for exploration purposes.

  2. Simulation and testing of a vertical organometallic vapor phase epitaxy reactor

    NASA Astrophysics Data System (ADS)

    Sani, R. A.; Barmawi, M.; Mindara, J. Y.

    1998-02-01

    The purpose of the study is to design a single wafer vertical organo-metallic vapor phase epitaxy (OMVPE) reactor which gives a uniform deposition around the symmetry axis. The vertical reactor under the consideration consist of a diffuser and a system of coaxial cylinders to laminarize the flow which may lead to a uniform deposition without rotating the susceptor. The simulation shows that for a susceptor with a radius of 2.5 cm, a uniformity can be achieved in a region of a radius of 2 cm within 1% for certain operating condition. The result is compared with the experimental measurement of TiO2 deposition from TTIP.

  3. 2001 Gordon Research Conference on Organometallic Chemistry. Final progress report [agenda and attendee list

    SciTech Connect

    Burns, Carol

    2001-07-27

    The Gordon Research Conference on Organometallic Chemistry was held at Salve Regina University, Newport, Rhode Island, July 22-27, 2001. The conference had 133 participants. The attendees represented the spectrum of endeavor in this field, coming from academia, industry, and government laboratories, and included US and foreign scientists, senior researchers, young investigators, and students. Emphasis was place on current unpublished research and discussion of the future target areas in this field. There was a conscious effort to stimulate lively discussion about the key issues in the field today. Time for formal presentations was limited in the interest of group discussions; poster sessions were held.

  4. Modular self-assembly, characterization, and host-guest chemistry of nanoscale organometallic architectures

    SciTech Connect

    Manna, J.; Kuehl, C.J.; Stang, P.J.; Muddiman, D.C.; Smith, R.D.

    1997-12-31

    The supramolecular synthesis and chemistry of organic macrocycles has been the focus of considerable study for over thirty years. In contrast, the chemistry of analogous inorganic and organometallic macrocycles is in it infancy; little is know about the stability, spectroscopic and physical properties, and chemistry of these species. We will report on the design of several unique supramolecular macrocycles and the characterization of these species by a range of spectroscopic techniques, including electrospray-ionization Fourier transform ion cyclotron resonance spectrometry. Preliminary data concerning the host-guest chemistry of these macrocycles will also be presented.

  5. Synthesis and characterization of azo-containing organometallic thin films for all optical switching applications

    NASA Astrophysics Data System (ADS)

    Gatri, R.; Fillaut, J.-L.; Mysliwiec, J.; Szukalski, A.; Bartkiewicz, S.; El-Ouazzani, H.; Guezguez, I.; Khammar, F.; Sahraoui, B.

    2012-05-01

    Novel photoresponsive materials based on azo-containing bifunctional ruthenium-acetylides have been synthesized. All optical switching based on the Optical Kerr Effect in the organometallic thin films based on ruthenium(II) acetylides containing an azobenzene moiety as a photochromic unit in the main pi-conjugated system dispersed in a poly(methyl methacrylate) matrix has been observed. The excitation beam was delivered from a picosecond laser at wavelength 532 nm while dynamics of induced sample birefringence was probed by a non-absorbed linearly polarized beam of cw He-Ne laser (632.8 nm). The influence of ruthenium part on dynamics of molecular motions has been shown.

  6. Exceptionally large two- and three-photon absorption cross-sections by OPV organometalation.

    PubMed

    Gao, Beibei; Mazur, Leszek M; Morshedi, Mahbod; Barlow, Adam; Wang, Huan; Quintana, Cristóbal; Zhang, Chi; Samoc, Marek; Cifuentes, Marie P; Humphrey, Mark G

    2016-07-01

    Oligo(p-phenylenevinylene)s (OPVs) containing up to 8 PV units and end-functionalized by ruthenium alkynyl groups have been prepared and their nonlinear absorption properties assessed using the Z-scan technique and employing low repetition rate femtosecond pulses. Exceptionally large two-photon absorption (ca. 12 500 GM at 725 nm) and three-photon absorption cross sections (ca. 1.6 × 10(-76) cm(6) s(2) at 1100 nm) are found for the 8PV-containing example, highlighting the potential of an "organometalation" approach to NLO-efficient organic materials. PMID:27297290

  7. The solid-state synthesis of metal nanoparticles from organometallic precursors.

    PubMed

    Wostek-Wojciechowska, Dorota; Jeszka, Jeremiasz K; Amiens, Catherine; Chaudret, Bruno; Lecante, Pierre

    2005-07-01

    Nanoparticles (NPs), average size of 2-5 nm, of ruthenium, cobalt, and rhodium have been prepared by an original method, namely the solid-state decomposition under dihydrogen of an organometallic precursor either dispersed in polymer films or directly as nanocrystals. The NPs dispersion, size, and morphology are investigated by transmission electron microscopy, and their structure by wide angle X-ray scattering. Infrared spectroscopy, after adsorption of carbon monoxide on the metal NPs surfaces, evidences a nonoxidized surface of high reactivity. PMID:15914154

  8. Self-Sufficient Formaldehyde-to-Methanol Conversion by Organometallic Formaldehyde Dismutase Mimic.

    PubMed

    van der Waals, Dominic; Heim, Leo E; Vallazza, Simona; Gedig, Christian; Deska, Jan; Prechtl, Martin H G

    2016-08-01

    The catalytic networks of methylotrophic organisms, featuring redox enzymes for the activation of one-carbon moieties, can serve as great inspiration in the development of novel homogeneously catalyzed pathways for the interconversion of C1 molecules at ambient conditions. An imidazolium-tagged arene-ruthenium complex was identified as an effective functional mimic of the bacterial formaldehyde dismutase, which provides a new and highly selective route for the conversion of formaldehyde to methanol in absence of any external reducing agents. Moreover, secondary amines are reductively methylated by the organometallic dismutase mimic in a redox self-sufficient manner with formaldehyde acting both as carbon source and reducing agent. PMID:27380865

  9. Preparation of low-resistivity n-type ZnSe by organometallic chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Stutius, W.

    1981-03-01

    Low-resistivity n-type ZnSe with p<0.05 W cm and n≳1017 cm-3 has been grown epitaxially on (100) GaAs substrates by a low-pressure low-temperature organometallic chemical vapor deposition process. Triethylaluminum is used as a dopant. The as-grown layers show a strong near-band-gap photoluminescence peak. The much weaker photoluminescence intensity at longer wavelength indicates that the concentration of deep centers is lower than in doped ZnSe prepared by other methods.

  10. Supported organometallic complexes: Surface chemistry, spectroscopy, and catalysis. Progress report, February 1, 1991--January 31, 1992

    SciTech Connect

    Marks, T.J.

    1992-02-01

    The long-range goal of this project is to elucidate and understand the surface chemistry and catalytic properties of well-defined, highly-reactive organometallic molecules (principally based upon abundant actinide, lanthanide, and early transition elements) adsorbed on metal oxides and halides. The nature of the adsorbed species is probed by a battery of chemical and physicochemical techniques, to understand the nature of the molecular-surface coordination chemistry and how this can give rise to extremely high catalytic activity. A complementary objective is to delineate the scope and mechanisms of the heterogeneous catalytic reactions, as well as to relate them both conceptually and functionally to model systems generated in solution.

  11. Effect of Mo and nano-Nd2O3 on the microstructure and wear resistance of laser cladding Ni-based alloy coatings

    NASA Astrophysics Data System (ADS)

    Ding, Lin; Hu, Shengsun; Quan, Xiumin; Shen, Junqi

    2016-04-01

    Three kinds of coatings were successfully prepared on Q235 steel by laser cladding technique through adulterating with Mo and nano-Nd2O3 into Ni-based alloys. The effect of Mo and nano-Nd2O3 on the microstructure and properties of Ni-based coatings was investigated systematically by means of optical microscopy, X-ray diffraction, scanning electron microscopy, energy-dispersive spectroscopy, and microhardness testing and wear testing. The results indicated a certain amount of fine grains and polygonal equiaxed grains synthesized after adding Mo and nano-Nd2O3. Both the microhardness and wear resistance of Ni-based coatings improved greatly with a moderate additional amount of Mo and nano-Nd2O3. The largest improvement in microhardness was 31.9 and 14.7 %, and the largest reduction in loss was 45.0 and 30.7 %, respectively, for 5.0 wt% Mo powders and 1.0 wt% nano-Nd2O3. The effect of Mo on microhardness and wear resistance of laser cladding Ni-based alloy coatings is greater than the effect of nano-Nd2O3.

  12. Implantation of Y- and Hf-ions into a F-doped Ni-base superalloy improving the oxidation resistance at high temperatures

    NASA Astrophysics Data System (ADS)

    Zschau, H.-E.; King, F.; Galetz, M. C.; Schütze, M.

    2015-12-01

    The surface modification of Ni-base alloys with low Al-contents (between 2 and 5 wt.%) with fluorine leads to the formation of a protective alumina scale under high temperature service conditions. The combined implantation of fluorine and reactive elements (Y, Hf) can increase the adherence of this alumina scale needed for technical applications.

  13. Interplay between experiments and calculations for organometallic clusters and caged clusters

    NASA Astrophysics Data System (ADS)

    Nakajima, Atsushi

    2015-12-01

    Clusters consisting of 10-1000 atoms exhibit size-dependent electronic and geometric properties. In particular, composite clusters consisting of several elements and/or components provide a promising way for a bottom-up approach for designing functional advanced materials, because the functionality of the composite clusters can be optimized not only by the cluster size but also by their compositions. In the formation of composite clusters, their geometric symmetry and dimensionality are emphasized to control the physical and chemical properties, because selective and anisotropic enhancements for optical, chemical, and magnetic properties can be expected. Organometallic clusters and caged clusters are demonstrated as a representative example of designing the functionality of the composite clusters. Organometallic vanadium-benzene forms a one dimensional sandwich structure showing ferromagnetic behaviors and anomalously large HOMO-LUMO gap differences of two spin orbitals, which can be regarded as spin-filter components for cluster-based spintronic devices. Caged clusters of aluminum (Al) are well stabilized both geometrically and electronically at Al12X, behaving as a "superatom".

  14. Interplay between experiments and calculations for organometallic clusters and caged clusters

    SciTech Connect

    Nakajima, Atsushi

    2015-12-31

    Clusters consisting of 10-1000 atoms exhibit size-dependent electronic and geometric properties. In particular, composite clusters consisting of several elements and/or components provide a promising way for a bottom-up approach for designing functional advanced materials, because the functionality of the composite clusters can be optimized not only by the cluster size but also by their compositions. In the formation of composite clusters, their geometric symmetry and dimensionality are emphasized to control the physical and chemical properties, because selective and anisotropic enhancements for optical, chemical, and magnetic properties can be expected. Organometallic clusters and caged clusters are demonstrated as a representative example of designing the functionality of the composite clusters. Organometallic vanadium-benzene forms a one dimensional sandwich structure showing ferromagnetic behaviors and anomalously large HOMO-LUMO gap differences of two spin orbitals, which can be regarded as spin-filter components for cluster-based spintronic devices. Caged clusters of aluminum (Al) are well stabilized both geometrically and electronically at Al{sub 12}X, behaving as a “superatom”.

  15. Synthesis and Microstructural Investigations of Organometallic Pd(II) Thiol-Gold Nanoparticles Hybrids

    PubMed Central

    2008-01-01

    In this work the synthesis and characterization of gold nanoparticles functionalized by a novel thiol-organometallic complex containing Pd(II) centers is presented. Pd(II) thiol,trans, trans-[dithiolate-dibis(tributylphosphine)dipalladium(II)-4,4′-diethynylbiphenyl] was synthesized and linked to Au nanoparticles by the chemical reduction of a metal salt precursor. The new hybrid made of organometallic Pd(II) thiol-gold nanoparticles, shows through a single S bridge a direct link between Pd(II) and Au nanoparticles. The size-control of the Au nanoparticles (diameter range 2–10 nm) was achieved by choosing the suitable AuCl4−/thiol molar ratio. The size, strain, shape, and crystalline structure of these functionalized nanoparticles were determined by a full-pattern X-ray powder diffraction analysis, high-resolution TEM, and X-ray photoelectron spectroscopy. Photoluminescence spectroscopy measurements of the hybrid system show emission peaks at 418 and 440 nm. The hybrid was exposed to gaseous NOxwith the aim to evaluate the suitability for applications in sensor devices; XPS measurements permitted to ascertain and investigate the hybrid –gas interaction. PMID:21350592

  16. Competing magnetic orderings and tunable topological states in two-dimensional hexagonal organometallic lattices

    NASA Astrophysics Data System (ADS)

    Kim, Hyun-Jung; Li, Chaokai; Feng, Ji; Cho, Jun-Hyung; Zhang, Zhenyu

    2016-01-01

    The exploration of topological states is of significant fundamental and practical importance in contemporary condensed matter physics, for which the extension to two-dimensional (2D) organometallic systems is particularly attractive. Using first-principles calculations, we show that a 2D hexagonal triphenyl-lead lattice composed of only main group elements is susceptible to a magnetic instability, characterized by a considerably more stable antiferromagnetic (AFM) insulating state rather than the topologically nontrivial quantum spin Hall state proposed recently. Even though this AFM phase is topologically trivial, it possesses an intricate emergent degree of freedom, defined by the product of spin and valley indices, leading to Berry curvature-induced spin and valley currents under electron or hole doping. Furthermore, such a trivial band insulator can be tuned into a topologically nontrivial matter by the application of an out-of-plane electric field, which destroys the AFM order, favoring instead ferrimagnetic spin ordering and a quantum anomalous Hall state with a nonzero topological invariant. These findings further enrich our understanding of 2D hexagonal organometallic lattices for potential applications in spintronics and valleytronics.

  17. Towards 9 weight percent, reversible, room temperature hydrogen adsorbents: Hydrogen saturated organometallic bucky balls

    NASA Astrophysics Data System (ADS)

    Zhao, Yufeng

    2005-03-01

    A new concept for high-capacity hydrogen absorbents is introduced by first-principles calculations. Transition metal (TM) atoms bound to fullerenes are proposed as a medium for high density, room temperature, ambient pressure storage of hydrogen. TMs bind to C60 or C48B12 by charge transfer interactions to produce stable organometallic bucky balls (OBBs) and bind to multiple dihydrogen molecules through the so-called Kubas interaction [1]. A particular scandium OBB can bind as many as eleven hydrogen atoms per TM, ten of which are bound in the form of dihydrogen molecular ligands that can be adsorbed and desorbed reversibly. In this case, the calculated binding energy is around 0.3 eV/H2, which is ideal for use on-board vehicles. The theoretical maximum retrievable H2 storage density is about 9 weight percent. This work was supported by the U.S. DOE EERE, BES/MS, and BES/CS under contract No. DEAC36-99GO10337. [1] G.J. Kubas, J. Organometallic Chem. 635, 37 (2001).

  18. Transporting and shielding photosensitisers by using water-soluble organometallic cages: a new strategy in drug delivery and photodynamic therapy.

    PubMed

    Therrien, Bruno

    2013-06-24

    Skin photosensitivity remains one of the main limitations in photodynamic therapy. In this Concept article a strategy to overcome this limitation is described, in which the photosensitizer is hidden inside the hydrophobic cavity of a water-soluble organometallic cage. The metallacage not only protects the photosensitizer from light, it also facilitates its delivery to cancer cells. PMID:23737435

  19. The effect of variations of cobalt content on the cyclic oxidation resistance of selected Ni-base superalloys

    NASA Technical Reports Server (NTRS)

    Barrett, C. A.

    1986-01-01

    Cobalt levels were systematically varied in the Ni-base turbine alloys U-700 (cast), U-700m(PM/HIP), Waspaloy, Mar-M-247, In-738, Nimonic-115, U-720, and SX-R-150. The cobalt levels ranged from 0 wt % to the nominal commercial content in each alloy. The alloys were tested in cyclic oxidation in static air at 1000, 1100 and 1150 C for 500, 200 and 100 hr respectively. An oxidation attack parameter, Ka derived from the specific weight change versus time data was used to evaluate the oxidation behavior of the alloys along with X-ray diffraction analysis of the surface oxides. The alloys tend to form either Cr2O3/chromite spinel or Al2O3/aluminate spinel depending on the CR/Al ratio in the alloys. Alloys with a ratio of 3.5 or higher tend to favor the Cr oxides while those under 3.0 form mostly Al oxides. In general the Al2O3/aluminate spinel forming alloys have the better oxidation resistance. Increased cobalt content lowers the scaling resistance of the higher Cr alloys while a 5.0 wt % Co content is optimum for the Al controlling alloys. The refractory metals, particularly Ta, appear beneficial to both types of oxides perhaps due to the formation of the omni-present trirutile Ni(Ta,Cb,Mo,W)2O6. Both scales break down as increasing amounts of NiO is formed.

  20. The effect of variations of cobalt content on the cyclic oxidation resistance of selected Ni-base superalloys

    NASA Technical Reports Server (NTRS)

    Barrett, Charles A.

    1987-01-01

    Cobalt levels were systematically varied in the Ni-base turbine alloys U-700 (cast), U-700m (PM/HIP), Waspaloy, Mar-M-247, In-738, Nimonic-115, U-720, and SX-R-150. the cobalt levels ranged from 0 wt pct to the nominal commercial content in each alloy. the alloys were tested in cyclic oxidation in static air at 1000, 1100 and 1150 C for 500, 200, and 100 hr, respectively. An oxidation attack parameter, Ka, derived from the specific weight change versus time data was used to evaluate the oxidation behavior of the alloys along with X-ray diffraction analysis of the surface oxides. The alloys tend to form either Cr2O3/chromite spinel or Al2O3/aluminate spinel depending on the Cr/Al ratio in the alloys. Alloys with a ratio of 3.5 or higher tend to favor the Cr oxides while those under 3.0 form mostly Al oxides. In general the Al2O3/aluminate spinel forming alloys have the better oxidation resistance. Increased cobalt content lowers the scaling resistance of the higher Cr allys while a 5.0 wt pct Co content is optimum for the Al controlling alloys. The refractory metals, particularly Ta, appear beneficial to both types of oxides, perhaps due to the formation of the omnipresent trirutile Ni(Ta, Cb, Mo, W)2O6. Both scales break down as increasing amounts of NiO are formed.

  1. Optical and analytical electron microscopy of ductility-dip cracking in Ni-base filler metal 52 -- Initial studies

    SciTech Connect

    Cola, M.J.; Teter, D.F.

    1998-01-01

    Microcharacterization studies were performed on weld-metal microstructures of a Ni-base filler metal. Specimens were taken from the fusion zone and the weld-metal heat-affected zone of transverse- and spot-Varestraint welds. The filler metal was first deposited onto a steel substrate by hot-wire, gas tungsten arc welding before specimen removal. Optical microscopy indicates the crack morphology is intergranular and is along high-angle, migrated grain boundaries. At low magnifications, scanning electron microscopy reveals a relatively smooth fracture surface. However, at higher magnifications the grain faces exhibit microductility. Analytical electron microscopy reveals high-angle, migrated grain boundaries decorated with MC (Ti, Cr) and M{sub 23}C{sub 6} (Cr, Ni, Fe) precipitates ranging from 10 to 200 n. Auger electron spectroscopy of pre-strained Gleeble specimens fractured in situ revealed internal ductility-dip cracks decorated with magnesium aluminate (MgAl{sub 2}O{sub 4}) spinel particles (1,000 nm).

  2. Real-time microstructure imaging by Laue microdiffraction: A sample application in laser 3D printed Ni-based superalloys

    NASA Astrophysics Data System (ADS)

    Zhou, Guangni; Zhu, Wenxin; Shen, Hao; Li, Yao; Zhang, Anfeng; Tamura, Nobumichi; Chen, Kai

    2016-06-01

    Synchrotron-based Laue microdiffraction has been widely applied to characterize the local crystal structure, orientation, and defects of inhomogeneous polycrystalline solids by raster scanning them under a micro/nano focused polychromatic X-ray probe. In a typical experiment, a large number of Laue diffraction patterns are collected, requiring novel data reduction and analysis approaches, especially for researchers who do not have access to fast parallel computing capabilities. In this article, a novel approach is developed by plotting the distributions of the average recorded intensity and the average filtered intensity of the Laue patterns. Visualization of the characteristic microstructural features is realized in real time during data collection. As an example, this method is applied to image key features such as microcracks, carbides, heat affected zone, and dendrites in a laser assisted 3D printed Ni-based superalloy, at a speed much faster than data collection. Such analytical approach remains valid for a wide range of crystalline solids, and therefore extends the application range of the Laue microdiffraction technique to problems where real-time decision-making during experiment is crucial (for instance time-resolved non-reversible experiments).

  3. Synthesis of Vertically Aligned ZnO Nanorods on Ni-Based Buffer Layers Using a Thermal Evaporation Process

    NASA Astrophysics Data System (ADS)

    Kuo, Dong-Hau; He, Jheng-Yu; Huang, Ying-Sheng

    2012-03-01

    Uniform, vertically aligned ZnO nanorods have been grown mainly on Au-coated and ZnO-coated sapphire substrates, ZnO- and GaN-coated substrates, or self-catalyzing substrates. Conventionally, Ni-coated substrates have resulted in thick rods with diameter more than 250 nm, rods with nonuniform distribution in diameter, or rods with an alignment problem. In the best result in this paper, slender, uniform, vertically aligned, solely UV-emitting ZnO nanorods with diameter of 110 ± 25 nm and length of 30 ± 10 μm have been successfully grown at 700°C for 2 h on sapphire substrates covered with Ni-based buffer layers by using metallic zinc and oxygen as reactants. Scanning electron microscopy and room-temperature photoluminescence have been used to investigate the effects of process conditions on the slenderness and vertical alignment of the ZnO rods. To develop the desired ZnO nanorods, etched sapphire substrates, a second metallic Sn buffer layer on top of a spin-coated nickel oxide layer, polyvinyl alcohol binder at 10% concentration in solution of iron nitrate, and pyrolysis and reduction reactions were involved. Defect photoemission for thick ZnO rods is attributed to insufficient oxygen supply during the growth process with fixed oxygen flow rate.

  4. Tailoring the physical properties of Ni-based single-phase equiatomic alloys by modifying the chemical complexity

    NASA Astrophysics Data System (ADS)

    Jin, K.; Sales, B. C.; Stocks, G. M.; Samolyuk, G. D.; Daene, M.; Weber, W. J.; Zhang, Y.; Bei, H.

    2016-02-01

    Equiatomic alloys (e.g. high entropy alloys) have recently attracted considerable interest due to their exceptional properties, which might be closely related to their extreme disorder induced by the chemical complexity. In order to understand the effects of chemical complexity on their fundamental physical properties, a family of (eight) Ni-based, face-center-cubic (FCC), equiatomic alloys, extending from elemental Ni to quinary high entropy alloys, has been synthesized, and their electrical, thermal, and magnetic properties are systematically investigated in the range of 4-300 K by combining experiments with ab initio Korring-Kohn-Rostoker coherent-potential-approximation (KKR-CPA) calculations. The scattering of electrons is significantly increased due to the chemical (especially magnetic) disorder. It has weak correlation with the number of elements but strongly depends on the type of elements. Thermal conductivities of the alloys are largely lower than pure metals, primarily because the high electrical resistivity suppresses the electronic thermal conductivity. The temperature dependence of the electrical and thermal transport properties is further discussed, and the magnetization of five alloys containing three or more elements is measured in magnetic fields up to 4 T.

  5. The wetting characteristics and surface tension of some ni-based alloys on yttria, hafnia, alumina, and zirconia substrates

    NASA Astrophysics Data System (ADS)

    Kanetkar, C. S.; Kacar, A. S.; Stefanescu, D. M.

    1988-07-01

    Sessile drop experiments were carried out in order to measure surface tensions and to investigate wetting characteristics of some Ni-based alloys on various ceramic substrates. The liquid-vapor surface tension (γLV) was found to be 1.764 N/m for pure Ni, 1.45 ± 0.11 N/m for Ni-20 pct Cr, 1.29 ± 0.06 N/m for Ni-20 pct Cr-1 pct Al, and 1.31 ± 0.09 N/m for Ni-20 pct Cr-4 pct Al. The commercial alloys UD520, UD718, UD720, and WASPALOY* showed non-wetting behavior on zirconia but wetting tendency on alumina substrates. Ni-20 pct Cr-1 pct Al showed non-wetting behavior on alumina, hafnia, and yttria substrates whereas Ni-20 pct Cr and Ni-20 pct Cr-4 pct Al were observed to be non-wetting on hafnia but wetting on yttria and alumina substrates. All the systems that exhibited wetting behavior were found to be non-wetting in the beginning; however, wet-ting improved with time. The wetting characteristics were apparently related to impurification of droplets during measurements, which is reflected in the solidification structure, rather than to the presence of oxides on the surface.

  6. Thin Co/Ni-based bottom pinned spin-transfer torque magnetic random access memory stacks with high annealing tolerance

    NASA Astrophysics Data System (ADS)

    Tomczak, Y.; Swerts, J.; Mertens, S.; Lin, T.; Couet, S.; Liu, E.; Sankaran, K.; Pourtois, G.; Kim, W.; Souriau, L.; Van Elshocht, S.; Kar, G.; Furnemont, A.

    2016-01-01

    Spin-transfer torque magnetic random access memory (STT-MRAM) is considered as a replacement for next generation embedded and stand-alone memory applications. One of the main challenges in the STT-MRAM stack development is the compatibility of the stack with CMOS process flows in which thermal budgets up to 400 °C are applied. In this letter, we report on a perpendicularly magnetized MgO-based tunnel junction (p-MTJ) on a thin Co/Ni perpendicular synthetic antiferromagnetic layer with high annealing tolerance. Tunnel magneto resistance (TMR) loss after annealing occurs when the reference layer loses its perpendicular magnetic anisotropy due to reduction of the CoFeB/MgO interfacial anisotropy. A stable Co/Ni based p-MTJ stack with TMR values of 130% at resistance-area products of 9 Ω μm2 after 400 °C anneal is achieved via moment control of the Co/Ta/CoFeB reference layer. Thinning of the CoFeB polarizing layer down to 0.8 nm is the key enabler to achieve 400 °C compatibility with limited TMR loss. Thinning the Co below 0.6 nm leads to a loss of the antiferromagnetic interlayer exchange coupling strength through Ru. Insight into the thickness and moment engineering of the reference layer is displayed to obtain the best magnetic properties and high thermal stability for thin Co/Ni SAF-based STT-MRAM stacks.

  7. Tailoring the physical properties of Ni-based single-phase equiatomic alloys by modifying the chemical complexity

    DOE PAGESBeta

    Jin, Ke; Sales, Brian C.; Stocks, George Malcolm; Samolyuk, German D.; Daene, Markus; Weber, William J.; Zhang, Yanwen; Bei, Hongbin

    2016-02-01

    We discovered that equiatomic alloys (e.g. high entropy alloys) have recently attracted considerable interest due to their exceptional properties, which might be closely related to their extreme disorder induced by the chemical complexity. To understand the effects of chemical complexity on their fundamental physical properties, a family of (eight) Ni-based, face-center-cubic (FCC), equiatomic alloys, extending from elemental Ni to quinary high entropy alloys, has been synthesized, and their electrical, thermal, and magnetic properties are systematically investigated in the range of 4–300 K by combining experiments with ab initio Korring-Kohn-Rostoker coherent-potential-approximation (KKR-CPA) calculations. The scattering of electrons is significantly increased duemore » to the chemical (especially magnetic) disorder. It has weak correlation with the number of elements but strongly depends on the type of elements. Thermal conductivities of the alloys are largely lower than pure metals, primarily because the high electrical resistivity suppresses the electronic thermal conductivity. Moreover, the temperature dependence of the electrical and thermal transport properties is further discussed, and the magnetization of five alloys containing three or more elements is measured in magnetic fields up to 4 T.« less

  8. Observations on the oxidation of Mn-modified Ni-base Haynes 230 alloy under SOFC exposure conditions

    SciTech Connect

    Yang, Z Gary; Xia, Gordon; Stevenson, Jeffry W.; Singh, Prabhakar

    2005-07-01

    The commercial Ni-base Haynes 230 alloy (Ni-Cr-Mo-W-Mn) was modified with two increased levels of Mn (1 and 2 wt per cent) and evaluated for its oxidation resistance under simulated SOFC interconnect exposure conditions. Oxidation rate, oxide morphology, oxide conductivity and thermal expansion were measured and compared with commercial Haynes 230. It was observed that additions of higher levels of Mn to the bulk alloy facilitated the formation of a bi-layered oxide scale that was comprised of an outer M3O4 (M=Mn, Cr, Ni) spinel-rich layer at the oxide – gas interface over a Cr2O3-rich sub-layer at the metal – oxide interface. The modified alloys showed higher oxidation rates and the formation of thicker oxide scales compared to the base alloy. The formation of a spinel-rich top layer improved the scale conductivity, especially during the early stages of the oxidation, but the higher scale growth rate resulted in an increase in the area-specific electrical resistance over time. Due to their face-centered cubic crystal structure, both commercial and modified alloys demonstrated a coefficient of thermal expansion that was higher than that of typical anode-supported and electrolyte-supported SOFCs.

  9. Evaluation of Closed Stress Corrosion Cracks in Ni-Based Alloy Weld Metal Using Subharmonic Phased Array

    NASA Astrophysics Data System (ADS)

    Horinouchi, Satoshi; Ikeuchi, Masako; Shintaku, Yohei; Ohara, Yoshikazu; Yamanaka, Kazushi

    2012-07-01

    Closed stress corrosion cracks (SCCs) have been generated in Ni-based alloy weld metal in nuclear power plants. The ultrasonic inspection is difficult because of the crack closure. For the application of new inspection methods and training/educating of inspection engineers, realistic closed SCC specimens are required. However, there is no means for forming such SCC specimens in a reasonable amount of time. Here, we present a two-step method. The first step is to form an open SCC in chemical solution. The second step is to close the SCC by generating oxide films between the crack faces in high-temperature pressurized water (HTPW). To verify the crack closure, we used a closed-crack imaging apparatus, the subharmonic phased array for crack evaluation (SPACE). Consequently, we found that parts of the SCC after 1321 h immersion were closed in the HTPW. Thus, we verified the two-step method for forming realistic closed SCC specimens in a reasonable amount of time.

  10. Tailoring the physical properties of Ni-based single-phase equiatomic alloys by modifying the chemical complexity

    PubMed Central

    Jin, K.; Sales, B. C.; Stocks, G. M.; Samolyuk, G. D.; Daene, M.; Weber, W. J.; Zhang, Y.; Bei, H.

    2016-01-01

    Equiatomic alloys (e.g. high entropy alloys) have recently attracted considerable interest due to their exceptional properties, which might be closely related to their extreme disorder induced by the chemical complexity. In order to understand the effects of chemical complexity on their fundamental physical properties, a family of (eight) Ni-based, face-center-cubic (FCC), equiatomic alloys, extending from elemental Ni to quinary high entropy alloys, has been synthesized, and their electrical, thermal, and magnetic properties are systematically investigated in the range of 4–300 K by combining experiments with ab initio Korring-Kohn-Rostoker coherent-potential-approximation (KKR-CPA) calculations. The scattering of electrons is significantly increased due to the chemical (especially magnetic) disorder. It has weak correlation with the number of elements but strongly depends on the type of elements. Thermal conductivities of the alloys are largely lower than pure metals, primarily because the high electrical resistivity suppresses the electronic thermal conductivity. The temperature dependence of the electrical and thermal transport properties is further discussed, and the magnetization of five alloys containing three or more elements is measured in magnetic fields up to 4 T. PMID:26832223

  11. An Improved Arrhenius Constitutive Model and Three-Dimensional Processing Map of a Solution-Treated Ni-Based Superalloy

    NASA Astrophysics Data System (ADS)

    Li, Hong-Bin; Feng, Yun-Li

    2016-01-01

    The hot deformation behaviors of a solution-treated Ni-based superalloy are investigated by hot compression tests over wide ranges of strain rate and forming temperature. Based on the experimental data, the effects of forming temperature and strain rate on the hot deformation behaviors are discussed in detail. Considering the effects of strain on material constants, comprehensive constitutive models are developed to describe the relationships between the flow stress, strain rate and forming temperature for the studied superalloy. The three-dimensional processing map is constructed to optimize the hot working parameters. Meanwhile, the microstructures are analyzed to correlate with the processing map. It is found that the flow stress is sensitive to the forming temperature, strain rate and deformation degree. With the increase of forming temperature or the decrease of strain rate, the flow stress significantly decreases. The predicted flow stresses agree well with experimentally measured results, which confirm that the developed constitutive model can accurately estimate the flow stress of the studied superalloy. The three-dimensional processing map shows that the optimum deformation windows for hot working are the domains with 980-1,040°C or 0.001-0.1 s^{-1} when the strain is 0.6. Also, it is found that the dynamically recrystallized grain size increases with the increase of forming temperature or the decrease of strain rate.

  12. An Improved Arrhenius Constitutive Model and Three-Dimensional Processing Map of a Solution-Treated Ni-Based Superalloy

    NASA Astrophysics Data System (ADS)

    Li, Hong-Bin; Feng, Yun-Li

    2016-01-01

    The hot deformation behaviors of a solution-treated Ni-based superalloy are investigated by hot compression tests over wide ranges of strain rate and forming temperature. Based on the experimental data, the effects of forming temperature and strain rate on the hot deformation behaviors are discussed in detail. Considering the effects of strain on material constants, comprehensive constitutive models are developed to describe the relationships between the flow stress, strain rate and forming temperature for the studied superalloy. The three-dimensional processing map is constructed to optimize the hot working parameters. Meanwhile, the microstructures are analyzed to correlate with the processing map. It is found that the flow stress is sensitive to the forming temperature, strain rate and deformation degree. With the increase of forming temperature or the decrease of strain rate, the flow stress significantly decreases. The predicted flow stresses agree well with experimentally measured results, which confirm that the developed constitutive model can accurately estimate the flow stress of the studied superalloy. The three-dimensional processing map shows that the optimum deformation windows for hot working are the domains with 980-1,040°C or 0.001-0.1 {s}^{-1} when the strain is 0.6. Also, it is found that the dynamically recrystallized grain size increases with the increase of forming temperature or the decrease of strain rate.

  13. Real-time microstructure imaging by Laue microdiffraction: A sample application in laser 3D printed Ni-based superalloys

    PubMed Central

    Zhou, Guangni; Zhu, Wenxin; Shen, Hao; Li, Yao; Zhang, Anfeng; Tamura, Nobumichi; Chen, Kai

    2016-01-01

    Synchrotron-based Laue microdiffraction has been widely applied to characterize the local crystal structure, orientation, and defects of inhomogeneous polycrystalline solids by raster scanning them under a micro/nano focused polychromatic X-ray probe. In a typical experiment, a large number of Laue diffraction patterns are collected, requiring novel data reduction and analysis approaches, especially for researchers who do not have access to fast parallel computing capabilities. In this article, a novel approach is developed by plotting the distributions of the average recorded intensity and the average filtered intensity of the Laue patterns. Visualization of the characteristic microstructural features is realized in real time during data collection. As an example, this method is applied to image key features such as microcracks, carbides, heat affected zone, and dendrites in a laser assisted 3D printed Ni-based superalloy, at a speed much faster than data collection. Such analytical approach remains valid for a wide range of crystalline solids, and therefore extends the application range of the Laue microdiffraction technique to problems where real-time decision-making during experiment is crucial (for instance time-resolved non-reversible experiments). PMID:27302087

  14. Initial assessment of Ni-base alloy performance in 0.1 MPa and supercritical CO2

    DOE PAGESBeta

    Pint, B. A.; Keiser, J. R.

    2015-09-25

    There is considerable interest in increasing the working temperature of both open and closed supercritical CO2 (sCO2) cycles to ≥700 °C. At these temperatures, it is unlikely that any Fe-base alloys have suitable strength and therefore the focus is on Ni-base alloys for this application. To begin addressing the lack of compatibility data under these conditions, initial work exposed a wide range of candidate alloys in 500-h exposures at 20 MPa (200 bar) CO2 at 650 -750 °C in high purity CO2. In general, the reaction products were thin and protective in these exposures. A smaller group of alloy couponsmore » focusing on chromia- and alumina-forming alloys was exposed for 500h in 0.1 MPa (1bar) air, CO2, CO2+O2 and CO2+H2O for comparison. Thus, the thin surface oxides formed were very similar to those formed at high pressure and no clear detrimental effect of CO2 oxidation or O2 or H2O impurities could be observed in these exposures.« less

  15. Modeling on the Solidification of 1J51 Fe-Ni-Based Alloy Ingot Under Vacuum Conditions

    NASA Astrophysics Data System (ADS)

    Zhang, Lifeng; Gao, Chen; Li, Chongwei; Peng, Jie

    2014-07-01

    In this article, a numerical simulation model on the solidification of 1J51 Fe-Ni based alloy under vacuum conditions was established using ProCAST software (ESI Group, Paris, France). The calculated temperature profiles of the mold and the solidification profile of the ingot were compared with the measurement, showing a reasonable agreement. The validated model was then used to study the effects of the insulation condition, filling rate, and maximum filling fraction on the solidification state and porosity distribution of the ingot. It was indicated that the shrinkage cavity position of ingot with zirconia fiber was lower than that without zirconia fiber, and the likelihood of centerline shrinkage porosity was independent of the insulation method. The position of macroporosity varied little when the filling rate was from 2.17 kg/s to 5.17 kg/s, while serious solidification defects occurred in the body of ingot when the filling rate was lower than 4.17 kg/s. Increasing the maximum filling fraction had a positive impact on the rise of shrinkage cavity position, but it was hardly advisable because the metal yield decreased with the increase of the maximum filling fraction. Considering the above parameters discussed in this article, it was proposed to remove the zirconia fiber layer for the industrial practice.

  16. Influences of synthesis methods and modifier addition on the properties of Ni-based catalysts supported on reticulated ceramic foams

    NASA Astrophysics Data System (ADS)

    Nikolić, Vesna; Kamberović, Željko; Anđić, Zoran; Korać, Marija; Sokić, Miroslav; Maksimović, Vesna

    2014-08-01

    A method of synthesizing Ni-based catalysts supported on α-Al2O3-based foams was developed. The foams were impregnated with aqueous solutions of metal chlorides under an air atmosphere using an aerosol route. Separate procedures involved calcination to form oxides and drying to obtain chlorides on the foam surface. The synthesized samples were subsequently reduced with hydrogen. With respect to the Ni/Al2O3 catalysts, the chloride reduction route enabled the formation of a Ni coating without agglomerates or cracks. Further research included catalyst modification by the addition of Pd, Cu, and Fe. The influences of the additives on the degree of reduction and on the low-temperature reduction effectiveness (533 and 633 K) were examined and compared for the catalysts obtained from oxides and chlorides. Greater degrees of reduction were achieved with chlorides, whereas Pd was the most effective modifier among those investigated. The reduction process was nearly complete at 533 K in the sample that contained 0.1wt% Pd. A lower reduction temperature was utilized, and the calcination step was avoided, which may enhance the economical and technological aspects of the developed catalyst production method.

  17. Real-time microstructure imaging by Laue microdiffraction: A sample application in laser 3D printed Ni-based superalloys.

    PubMed

    Zhou, Guangni; Zhu, Wenxin; Shen, Hao; Li, Yao; Zhang, Anfeng; Tamura, Nobumichi; Chen, Kai

    2016-01-01

    Synchrotron-based Laue microdiffraction has been widely applied to characterize the local crystal structure, orientation, and defects of inhomogeneous polycrystalline solids by raster scanning them under a micro/nano focused polychromatic X-ray probe. In a typical experiment, a large number of Laue diffraction patterns are collected, requiring novel data reduction and analysis approaches, especially for researchers who do not have access to fast parallel computing capabilities. In this article, a novel approach is developed by plotting the distributions of the average recorded intensity and the average filtered intensity of the Laue patterns. Visualization of the characteristic microstructural features is realized in real time during data collection. As an example, this method is applied to image key features such as microcracks, carbides, heat affected zone, and dendrites in a laser assisted 3D printed Ni-based superalloy, at a speed much faster than data collection. Such analytical approach remains valid for a wide range of crystalline solids, and therefore extends the application range of the Laue microdiffraction technique to problems where real-time decision-making during experiment is crucial (for instance time-resolved non-reversible experiments). PMID:27302087

  18. Detached Melt Nucleation during Diffusion Brazing of a Technical Ni-based Superalloy: A Phase-Field Study

    NASA Astrophysics Data System (ADS)

    Böttger, B.; Apel, M.; Laux, B.; Piegert, S.

    2015-06-01

    Advanced solidification processes like welding, soldering, and brazing are often characterized by their specific solidification conditions. But they also may include different types of melting processes which themselves are strongly influenced by the initial microstructures and compositions of the applied materials and therefore are decisive for the final quality and mechanical properties of the joint. Such melting processes are often not well- understood because - compared to other fields of solidification science - relatively little research has been done on melting by now. Also, regarding microstructure simulation, melting has been strongly neglected in the past, although this process is substantially different from solidification due to the reversed diffusivities of the involved phases. In this paper we present phase-field simulations showing melting, solidification and precipitation of intermetallic phases during diffusion brazing of directionally solidified and heat-treated high-alloyed Ni- based gas turbine blade material using different boron containing braze alloys. Contrary to the common belief, melting of the base material is not always planar and can be further accompanied by detached nucleation and growth of a second liquid phase inside the base material leading to polycrystalline morphologies of the joint after solidification. These findings are consistent with results from brazed laboratory samples, which were characterized by EDX and optical microscopy, and can be explained in terms of specific alloy thermodynamics and inter-diffusion kinetics. Consequences of the gained new understanding for brazing of high- alloyed materials are discussed.

  19. Low cycle fatigue and creep-fatigue behavior of Ni-based alloy 230 at 850 C

    SciTech Connect

    Chen, Xiang; Yang, Zhiqing; Sokolov, Mikhail A; ERDMAN III, DONALD L; Mo, Kun; Stubbins, James

    2013-01-01

    Strain-controlled low cycle fatigue (LCF) and creep-fatigue testing of Ni-based alloy 230 were carried out at 850 C. The material creep-fatigue life decreased compared with its low cycle fatigue life at the same total strain range. Longer hold time at peak tensile strain further reduced the material creep-fatigue life. Based on the electron backscatter diffraction, a novel material deformation characterization method was applied, which revealed that in low cycle fatigue testing as the total strain range increased, the deformation was segregated to grain boundaries since the test temperature was higher than the material equicohesive temperature and grain boundaries became weaker regions compared with grains. Creep-fatigue tests enhanced the localized deformation, resulting in material interior intergranular cracking, and accelerated material damage. Precipitation in alloy 230 helped slip dispersion, favorable for fatigue property, but grain boundary cellular precipitates formed after material exposure to the elevated temperature had a deleterious effect on the material low cycle fatigue and creep-fatigue property.

  20. Effects of thermal aging on microstructures of low alloy steel-Ni base alloy dissimilar metal weld interfaces

    NASA Astrophysics Data System (ADS)

    Choi, Kyoung Joon; Kim, Jong Jin; Lee, Bong Ho; Bahn, Chi Bum; Kim, Ji Hyun

    2013-10-01

    In this study, the advanced instrumental analysis has been performed to investigate the effect of long-term thermal aging on the microstructural evolution in the fusion boundary region between weld metal and low alloy steel in dissimilar metal welds. A representative dissimilar weld mock-up made of Alloy 690-Alloy 152-A533 Gr. B was fabricated and aged at 450 °C for 2750 h. The micro- and nano-scale characterization were conducted mainly near in a weld root region by using optical microscopy, scanning electron microscopy, transmission electron microscopy, and three dimensional atom probe tomography. It was observed that the weld root was generally divided into several regions including dilution zone in the Ni-base alloy weld metal, fusion boundary, and heat-affected zone in the low alloy steel. A steep gradient was shown in the chemical composition profile across the interface between A533 Gr. B and Alloy 152. The precipitation of carbides was also observed along and near the fusion boundary of as-welded and aged dissimilar metal joints. It was also found that the precipitation of Cr carbides was enhanced by the thermal aging near the fusion boundary.

  1. Effect of Creep and Oxidation on Reduced Creep-Fatigue life of Ni-based Alloy 617 at 850 C

    SciTech Connect

    Chen, Xiang; Yang, Zhiqing; Sokolov, Mikhail A; ERDMAN III, DONALD L; Mo, Kun; Stubbins, James

    2014-01-01

    Low cycle fatigue (LCF) and creep fatigue testing of Ni-based alloy 617 was carried out at 850 C. Compared with its LCF life, the material s creep fatigue life decreases to different extents depending on test conditions. To elucidate the microstructure-fatigue property relationship for alloy 617 and the effect of creep and oxidation on its fatigue life, systematic microstructural investigations were carried out using scanning electron microscopy, energy-dispersive X-ray spectroscopy, and electron backscatter diffraction (EBSD). In LCF tests, as the total strain range increased, deformations concentrated near high angle grain boundaries (HAGBs). The strain hold period in the creep fatigue tests introduced additional creep damage to the material, which revealed the detrimental effect of the strain hold time on the material fatigue life in two ways. First, the strain hold time enhanced the localized deformation near HAGBs, resulting in the promotion of intergranular cracking of alloy 617. Second, the strain hold time encouraged grain boundary sliding, which resulted in interior intergranular cracking of the material. Oxidation accelerated the initiation of intergranular cracking in alloy 617. In the crack propagation stage, if oxidation was promoted and the cyclic oxidation damage was greater than the fatigue damage, oxidation-assisted intergranular crack growth resulted in a significant reduction in the material s fatigue life.

  2. Deactivation Mechanisms of Ni-Based Tar Reforming Catalysts As Monitored by X-ray Absorption Spectroscopy

    SciTech Connect

    Yung, Matthew M.; Kuhn, John N.

    2010-12-06

    Deactivation mechanisms of alumina-supported, Ni-based catalysts for tar reforming in biomass-derived syngas were evaluated using extended X-ray absorption fine structure (EXAFS) spectroscopy. Catalysts were characterized before and after catalytic reaction cycles and regeneration procedures, which included oxidation by a mixture of steam and air, and reduction in hydrogen. Qualitative analysis of the EXAFS spectra revealed that oxidation of a portion of the Ni in the catalysts to form an oxide phase and/or a sulfide phase were likely scenarios that led to catalyst deactivation with time-on-stream and with increased reaction cycles. Deactivation through carbon deposition, phosphorus poisoning, or changes in particle size were deemed as unlikely causes. Quantitative analysis of the EXAFS spectra indicated sulfur poisoning occurred with time-on-stream, and the contaminating species could not be completely removed during the regeneration protocols. The results also verified that Ni-containing oxide phases (most likely a spinel also containing Mg and Al) formed and contributed to the deactivation. This study validates the need for developing catalyst systems that will protect Ni from sulfur poisoning and oxide formation at elevated reaction and regeneration temperatures.

  3. Microstructural Characterisation of Non-Magnetic Ni-BASED Biaxially Textured Substrates for Hts Coated Conductor Applications

    NASA Astrophysics Data System (ADS)

    Villa, E.; Tuissi, A.; Tomov, R.; Evetts, J. E.

    For the production of HTS coated conductor devices, NiV and NiCr (Ni-based alloys) are the most important, non-magnetic, high strength and biaxially textured substrates developed from pure Ni. The Ni88V12 and Ni85Cr15 (at. %) alloys have been melted in Plasma Arc Furnace and textured tapes have been prepared, after heavy cold rolling, by recrystallization heat treatment under high vacuum. The suitable working conditions have been found to obtain not only the {100} <001> cube texture but also the correct grain shape and size for the following deposition process. Out of plane orientation of these substrates has been investigated by θ-2θ X-ray diffraction measurements and in plane orientation study has been completed by pole figures. The microstructure has been observed by optical microscopy: it has been carried out on samples obtained after an annealing treatment (Grain Size Adjustment) and on recrystallized samples in different conditions. As preliminary mechanical investigation the microhardness values have been detected for each step of the working procedure. The accuracy of the cubic texture and the grain structure are affected by the processing condition, in particular the temperature of the GSA seems a very important parameter which influences the final characteristics of the tapes.

  4. First-Principles Molecular Dynamics Studies of Organometallic Complexes and Homogeneous Catalytic Processes.

    PubMed

    Vidossich, Pietro; Lledós, Agustí; Ujaque, Gregori

    2016-06-21

    Computational chemistry is a valuable aid to complement experimental studies of organometallic systems and their reactivity. It allows probing mechanistic hypotheses and investigating molecular structures, shedding light on the behavior and properties of molecular assemblies at the atomic scale. When approaching a chemical problem, the computational chemist has to decide on the theoretical approach needed to describe electron/nuclear interactions and the composition of the model used to approximate the actual system. Both factors determine the reliability of the modeling study. The community dedicated much effort to developing and improving the performance and accuracy of theoretical approaches for electronic structure calculations, on which the description of (inter)atomic interactions rely. Here, the importance of the model system used in computational studies is highlighted through examples from our recent research focused on organometallic systems and homogeneous catalytic processes. We show how the inclusion of explicit solvent allows the characterization of molecular events that would otherwise not be accessible in reduced model systems (clusters). These include the stabilization of nascent charged fragments via microscopic solvation (notably, hydrogen bonding), transfer of charge (protons) between distant fragments mediated by solvent molecules, and solvent coordination to unsaturated metal centers. Furthermore, when weak interactions are involved, we show how conformational and solvation properties of organometallic complexes are also affected by the explicit inclusion of solvent molecules. Such extended model systems may be treated under periodic boundary conditions, thus removing the cluster/continuum (or vacuum) boundary, and require a statistical mechanics simulation technique to sample the accessible configurational space. First-principles molecular dynamics, in which atomic forces are computed from electronic structure calculations (namely, density

  5. Distinctive Reaction Pathways at Base Metals in High-Spin Organometallic Catalysts.

    PubMed

    Holland, Patrick L

    2015-06-16

    Inexpensive "base" metals are more affordable and sustainable than precious metals and also offer opportunities to discover new mechanisms for selective catalytic reactions. Base metal complexes can have high-spin electronic configurations that are rare in precious metal complexes. This Account describes some concepts relevant to high-spin organometallic complexes, focusing on our recent work with β-diketiminate complexes of iron and cobalt. Even though high-spin organometallic complexes have some unfamiliar spectroscopic properties, they can be studied using NMR spectroscopy as well as techniques that focus on the magnetism brought about by the unpaired electrons. Understanding the mechanisms of reactions using these complexes can be complicated, because complexes with a high-spin electronic configuration may need to change spin states to avoid high barriers for reaction. These spin-state changes can be rapid, and the ability of an excited spin state to "cut through" the barrier for a reaction can lead to spin acceleration. These concepts, originally developed by Poli, Shaik, Schwarz, and Harvey, are applied here to the fundamental organometallic reaction of β-hydride elimination (BHE). Experimentally validated density-functional calculations show spin acceleration in BHE using three-coordinate iron(II) and cobalt(II) complexes. A square-planar transition state is particularly beneficial for accelerating BHE when a high-spin iron(II) complex goes from an S = 2 ground state to an S = 1 transition state or when a high-spin cobalt(II) complex goes from an S = 3/2 ground state to an S = 1/2 transition state. The relative energies of the spin states can be controlled with the choice of the supporting ligand. Using an appropriate ligand, isomerization of 1-alkenes to their Z-2 isomers can be catalyzed in high yields using the cobalt(II) alkyl complexes as catalysts. Though an earlier paper attributed the regioselectivity and stereoselectivity to the preferred geometry

  6. Toward new organometallic architectures: synthesis of carbene-centered rhodium and palladium bisphosphine complexes. stability and reactivity of [PC(BIm)PRh(L)][PF6] pincers.

    PubMed

    Plikhta, Andriy; Pöthig, Alexander; Herdtweck, Eberhardt; Rieger, Bernhard

    2015-10-01

    In this article, we report the synthesis of a tridentate carbene-centered bisphosphine ligand precursor and its complexes. The developed four-step synthetic strategy of a new PC(BIm)P pincer ligand represents the derivatization of benzimidazole in the first and third positions by (diphenylphosphoryl)methylene synthone, followed by phosphine deprotection and subsequent insertion of a noncoordinating anion. The obtained ligand precursor undergoes complexation, with PdCl2 and [μ-OCH3Rh(COD)]2 smoothly forming the target organometallics [PC(BIm)PPdCl][PF6] and [PC(BIm)PRh(L)][PF6] under mild hydrogenation conditions. A more detailed study of the rhodium complexes [PC(BIm)PRh(L)][PF6] reveals significant thermal stability of the PC(BIm)PRh moiety in the solid state as well as in solution. The chemical behavior of 1,3-bis(diphenylphosphinomethylene)benzimidazol-2-ylrhodium acetonitrile hexafluorophosphate has been screened under decarbonylation, hydrogenation, and hydroboration reaction conditions. Thus, the PC(BIm)PRh(I) complex is a sufficiently stable compound, with the potential to be applied in catalysis. PMID:26390389

  7. 1H, 13C, 15N and 195Pt NMR studies of Au(III) and Pt(II) chloride organometallics with 2-phenylpyridine.

    PubMed

    Pazderski, Leszek; Pawlak, Tomasz; Sitkowski, Jerzy; Kozerski, Lech; Szłyk, Edward

    2009-11-01

    (1)H, (13)C, (15)N and (195)Pt NMR studies of gold(III) and platinum(II) chloride organometallics with N(1),C(2')-chelated, deprotonated 2-phenylpyridine (2ppy*) of the formulae [Au(2ppy*)Cl(2)], trans(N,N)-[Pt(2ppy*)(2ppy)Cl] and trans(S,N)-[Pt(2ppy*)(DMSO-d(6))Cl] (formed in situ upon dissolving [Pt(2ppy*)(micro-Cl)](2) in DMSO-d(6)) were performed. All signals were unambiguously assigned by HMBC/HSQC methods and the respective (1)H, (13)C and (15)N coordination shifts (i.e. differences between chemical shifts of the same atom in the complex and ligand molecules: Delta(1H)(coord) = delta(1H)(complex) - delta(1H)(ligand), Delta(13C)(coord) = delta(13C)(complex) - delta(13C)(ligand), Delta(15N)(coord) = delta(15N)(complex) - delta(15N)(ligand)), as well as (195)Pt chemical shifts and (1)H-(195)Pt coupling constants discussed in relation to the known molecular structures. Characteristic deshielding of nitrogen-adjacent H(6) protons and metallated C(2') atoms as well as significant shielding of coordinated N(1) nitrogens is discussed in respect to a large set of literature NMR data available for related cyclometallated compounds. PMID:19691018

  8. Rational Design of Polynuclear Organometallic Assemblies from a Simple Heteromultifunctional Ligand.

    PubMed

    Zhang, Long; Lin, Yue-Jian; Li, Zhen-Hua; Jin, Guo-Xin

    2015-10-28

    In modern coordination chemistry, supramolecular coordination complexes take advantage of ligand design to control the shapes and sizes of such architectures. Here we describe how to utilize starting building blocks and a multifunctional ligand to rationally design and synthesize different types of discrete assemblies. Using a hydroxamate ligand featuring two pair of chelating sites together with half-sandwich iridium and rhodium fragments, we were able to construct a series multinuclear organometallic macrocycles and cages through stepwise coordination-driven self-assembly. Experimental observations, supported by computational work, show that selective coordination modes were ascribed to the significant electronic density differences of the two chelating sites, (O,O') and (N,N'). The results underline the advantages of the discrimination between soft and hard binding sites, and suggest that hydroxamic acids can be used as a versatile class of facile multifunctional scaffold for the construction of novel two-dimensional and three-dimensional architectures. PMID:26440304

  9. Performance of Density Functional Theory and Relativistic Effective Core Potential for Ru-Based Organometallic Complexes.

    PubMed

    Paranthaman, Selvarengan; Moon, Jiwon; Kim, Joonghan; Kim, Dong Eon; Kim, Tae Kyu

    2016-04-01

    Herein a performance assessment of density functionals used for calculating the structural and energetic parameters of bi- and trimetallic Ru-containing organometallic complexes has been performed. The performance of four popular relativistic effective core potentials (RECPs) has also been assessed. On the basis of the calculated results, the MN12-SX (range-separated hybrid functional) demonstrates good performance for calculating the molecular structures, while MN12-L (local functional) performs well for calculating the energetics, including that of the Ru-Ru bond breaking process. The choice of appropriate density functional is a crucial factor for calculating the energetics. The LANL08 demonstrates the lowest performance of the RECPs for calculating the molecular structures, especially the Ru-Ru bond length. PMID:26986051

  10. On-Surface Observation of the Formation of Organometallic Complex in a Supramolecular Network

    NASA Astrophysics Data System (ADS)

    Li, Yibao; Cheng, Linxiu; Liu, Chunhua; Liu, Wei; Fan, Yulan; Fan, Xiaolin; Zeng, Qingdao

    2015-06-01

    The on-surface formation of organometallic monomers or oligomers, especially in supramolecular network, attracts an extensive interest for chemists and material scientist. In this work, we have investigated metal coordination between zinc (II) phthalocyanine (ZnPc) and 1, 3-di (4-pyridyl) propane (dipy-pra) in the 2, 6, 11-tricarboxydecyloxy-3, 7, 10-triundecyloxy triphenylene (asym-TTT) supramolecular template by means of scanning tunneling microscopy (STM) on highly oriented pyrolytic graphite (HOPG) substrate under ambient conditions. The experimental results demonstrate that every two ZnPc molecules in one nano-reactor connect with each other through one dipy-pra molecule by metal-coordination interaction. In this coordinating process, the template of asym-TTT supramolecular networks plays a significant role.

  11. Metal-organometallic polymers and frameworks derived from facially metalated arylcarboxylates

    NASA Astrophysics Data System (ADS)

    Kumalah Robinson, Sayon A.

    The interest in coordination polymers, also known as metal-organic frameworks, has risen drastically over the past 2 decades. In this time, the field has matured and given rise to a diverse range of crystalline structures possessing various functionalities. Coordination polymers are typically formed from the self assembly of metal ions which serve as nodes and organic ligands which act as bridges. By the careful selection of the organic ligand and the metal ion, the overall physical properties of the material may be tuned. In this work, the use of organometallic bridging ligands are explored using facially metalated aryl carboxylates ligands to synthesize metal-organometallic frameworks (MOMFs). Therefore, with the aim of synthesizing [CpM]+-functionalized (M = FeII, RuII; Cp = cyclopentadienyl) coordination polymers and metal organic frameworks, various [CpFe]+and [CpRu] + functionalized aryl carboxylates were synthesized and characterized. In particular, the [CpFe]+-functionalized benzoic, terephthalic and trimesic acids as well as the [CpRu]+-functionalized terephthalic acid were made. Using the [CpFe]+ complexes of the benzoic and terephthalic acid as bridging ligands, a number of 1D and 2D coordination polymers were synthesized. For instance, the reaction of [CpFe]+-functionalized benzoic acid with CdCl2 yielded the 1D chain of [Cd(benzoate)Cl 2]˙H2O whilst the reaction of [CpFe]+-functionalized terephthalic acid with Cu(NO3)2˙6H2O yielded a 2D square grid sheet. Using the [CpFe]+-functionalized terephthalic acid, a series of polymorphic, 3D metal-organometallic frameworks of the general formula [M3(terephthalate)4(mu-H2O)2(H 2O)2][NO3]2˙xsolvent (M = Co II, NiII ; solvent = EtOH, DMF, H2O) were synthesized and fully characterized. The polymorphic nature of these frameworks may be attributed to the different orientations that the [CpFe]+ moiety may adapt within the cavities in the 3D frameworks. The selectivity of the desolvated forms of the polymorphs for

  12. On-Surface Observation of the Formation of Organometallic Complex in a Supramolecular Network

    PubMed Central

    Li, Yibao; Cheng, Linxiu; Liu, Chunhua; Liu, Wei; Fan, Yulan; Fan, Xiaolin; Zeng, Qingdao

    2015-01-01

    The on-surface formation of organometallic monomers or oligomers, especially in supramolecular network, attracts an extensive interest for chemists and material scientist. In this work, we have investigated metal coordination between zinc (II) phthalocyanine (ZnPc) and 1, 3-di (4-pyridyl) propane (dipy-pra) in the 2, 6, 11-tricarboxydecyloxy-3, 7, 10-triundecyloxy triphenylene (asym-TTT) supramolecular template by means of scanning tunneling microscopy (STM) on highly oriented pyrolytic graphite (HOPG) substrate under ambient conditions. The experimental results demonstrate that every two ZnPc molecules in one nano-reactor connect with each other through one dipy-pra molecule by metal-coordination interaction. In this coordinating process, the template of asym-TTT supramolecular networks plays a significant role. PMID:26061532

  13. A Photoferroelectric Perovskite-Type Organometallic Halide with Exceptional Anisotropy of Bulk Photovoltaic Effects.

    PubMed

    Sun, Zhihua; Liu, Xitao; Khan, Tariq; Ji, Chengmin; Asghar, Muhammad Adnan; Zhao, Sangen; Li, Lina; Hong, Maochun; Luo, Junhua

    2016-05-23

    Perovskite-type ferroelectrics composed of organometallic halides are emerging as a promising alternative to conventional photovoltaic devices because of their unique photovoltaic effects (PVEs). A new layered perovskite-type photoferroelectric, bis(cyclohexylaminium) tetrabromo lead (1), is presented. The material exhibits an exceptional anisotropy of bulk PVEs. Upon photoexcitation, superior photovoltaic behaviors are created along its inorganic layers, which are composed of corner-sharing PbBr6 octahedra. Semiconducting activity with remarkable photoconductivity is achieved in the vertical direction, showing sizeable on/off current ratios (>10(4) ), which compete with the most active photovoltaic material CH3 NH3 PbI3 . In 1 the temperature-dependence of photovoltage coincides fairly well with that of polarization, confirming the dominant role of ferroelectricity in such highly anisotropic PVEs. This finding sheds light on bulk PVEs in ferroelectric materials, and promotes their application in optoelectronic devices. PMID:27088882

  14. Lattice-Directed Formation of Covalent and Organometallic Molecular Wires by Terminal Alkynes on Ag Surfaces.

    PubMed

    Liu, Jing; Chen, Qiwei; Xiao, Lianghong; Shang, Jian; Zhou, Xiong; Zhang, Yajie; Wang, Yongfeng; Shao, Xiang; Li, Jianlong; Chen, Wei; Xu, Guo Qin; Tang, Hao; Zhao, Dahui; Wu, Kai

    2015-06-23

    Surface reactions of 2,5-diethynyl-1,4-bis(phenylethynyl)benzene on Ag(111), Ag(110), and Ag(100) were systematically explored and scrutinized by scanning tunneling microscopy, molecular mechanics simulations, and density functional theory calculations. On Ag(111), Glaser coupling reaction became dominant, yielding one-dimensional molecular wires formed by covalent bonds. On Ag(110) and Ag(100), however, the terminal alkynes reacted with surface metal atoms, leading to one-dimensional organometallic nanostructures. Detailed experimental and theoretical analyses revealed that such a lattice dependence of the terminal alkyne reaction at surfaces originated from the matching degree between the periodicities of the produced molecular wires and the substrate lattice structures. PMID:25990647

  15. Radical SAM catalysis via an organometallic intermediate with an Fe-[5'-C]-deoxyadenosyl bond.

    PubMed

    Horitani, Masaki; Shisler, Krista; Broderick, William E; Hutcheson, Rachel U; Duschene, Kaitlin S; Marts, Amy R; Hoffman, Brian M; Broderick, Joan B

    2016-05-13

    Radical S-adenosylmethionine (SAM) enzymes use a [4Fe-4S] cluster to cleave SAM to initiate diverse radical reactions. These reactions are thought to involve the 5'-deoxyadenosyl radical intermediate, which has not yet been detected. We used rapid freeze-quenching to trap a catalytically competent intermediate in the reaction catalyzed by the radical SAM enzyme pyruvate formate-lyase activating enzyme. Characterization of the intermediate by electron paramagnetic resonance and (13)C, (57)Fe electron nuclear double-resonance spectroscopies reveals that it contains an organometallic center in which the 5' carbon of a SAM-derived deoxyadenosyl moiety forms a bond with the unique iron site of the [4Fe-4S] cluster. Discovery of this intermediate extends the list of enzymatic bioorganometallic centers to the radical SAM enzymes, the largest enzyme superfamily known, and reveals intriguing parallels to B12 radical enzymes. PMID:27174986

  16. Lateral epitaxial overgowth of GaAs by organometallic chemical vapor deposition

    NASA Technical Reports Server (NTRS)

    Gale, R. P.; Mcclelland, R. W.; Fan, J. C. C.; Bozler, C. O.

    1982-01-01

    Lateral epitaxial overgrowth of GaAs by organometallic chemical vapor deposition has been demonstrated. Pyrolytic decomposition of trimethylgallium and arsine, without the use of HCl, was used to deposit GaAs on substrates prepared by coating (110) GaAs wafers with SiO2, then using photolithography to open narrow stripes in the oxide. Lateral overgrowth was seeded by epitaxial deposits formed on the GaAs surfaces exposed by the stripe openings. The extent of lateral overgrowth was investigated as a function of stripe orientation and growth temperature. Ratios of lateral to vertical growth rates greater than five have been obtained. The lateral growth is due to surface-kinetic control for the two-dimensional growth geometry studied. A continuous epitaxial GaAs layer 3 microns thick has been grown over a patterned mask on a GaAs substrate and then cleaved from the substrate.

  17. Synthesis and characterization of nanowire coils of organometallic coordination polymers for controlled cargo release.

    PubMed

    Liang, Guodong; Ni, Huan; Bao, Suping; Zhu, Fangming; Gao, Haiyang; Wu, Qing

    2014-06-12

    Nanowire coils of organometallic coordination polymers have been synthesized for the first time by using the emulsion periphery polymerization technique. An amphiphilic triblock copolymer terminated with inclusion complex of β-cyclodextrin and 4,4'-bipyridine self-assembles into oil-in-water emulsion in a toluene/water mixture. Subsequent coordination of bipyridine with Ni(II) in periphery of emulsions results in the formation of coordination polymer nanowire coils. The nanowire coils are composed of nanowires with diameter of 2 nm. Nanowire coils exhibit enhanced thermal stability in contrast to their parent triblock copolymer. Interestingly, nanowire coils are capable of encapsulating organic cargoes. Encapsulated cargoes can be selectively extracted from nanowire coils without damaging nanowire coils. Nanowire coils are potential candidates for encapsulating and controlled release of organic cargoes. PMID:24842771

  18. Precision design of ethylene- and polar-monomer-based copolymers by organometallic-mediated radical polymerization.

    PubMed

    Kermagoret, Anthony; Debuigne, Antoine; Jérôme, Christine; Detrembleur, Christophe

    2014-03-01

    The copolymerization of ethylene with polar monomers is a major challenge when it comes to the manufacture of materials with potential for a wide range of commercial applications. In the chemical industry, free-radical polymerization is used to make a large proportion of such copolymers, but the forcing conditions result in a lack of fine control over the architecture of the products. Herein we introduce a synthetic tool, effective under mild experimental conditions, for the precision design of unprecedented ethylene- and polar-monomer-based copolymers. We demonstrate how an organocobalt species can control the growth of the copolymer chains, their composition and the monomer distribution throughout the chain. By fine tuning the ethylene pressure during polymerization and by exploiting a unique reactive mode of the end of the organometallic chain, novel block-like copolymer structures can be prepared. This highly versatile synthetic platform provides access to a diverse range of polymer materials. PMID:24557131

  19. Precision design of ethylene- and polar-monomer-based copolymers by organometallic-mediated radical polymerization

    NASA Astrophysics Data System (ADS)

    Kermagoret, Anthony; Debuigne, Antoine; Jérôme, Christine; Detrembleur, Christophe

    2014-03-01

    The copolymerization of ethylene with polar monomers is a major challenge when it comes to the manufacture of materials with potential for a wide range of commercial applications. In the chemical industry, free-radical polymerization is used to make a large proportion of such copolymers, but the forcing conditions result in a lack of fine control over the architecture of the products. Herein we introduce a synthetic tool, effective under mild experimental conditions, for the precision design of unprecedented ethylene- and polar-monomer-based copolymers. We demonstrate how an organocobalt species can control the growth of the copolymer chains, their composition and the monomer distribution throughout the chain. By fine tuning the ethylene pressure during polymerization and by exploiting a unique reactive mode of the end of the organometallic chain, novel block-like copolymer structures can be prepared. This highly versatile synthetic platform provides access to a diverse range of polymer materials.

  20. Anodic Deposition of a Robust Iridium-Based Water-Oxidation Catalyst from Organometallic Precursors

    SciTech Connect

    Blakemore, James D; Schley, Nathan D; Olack, G.; Incarvito, Christopher D; Brudvig, Gary W; Crabtree, Robert H

    2011-01-01

    Artificial photosynthesis, modeled on natural light-driven oxidation of water in Photosystem II, holds promise as a sustainable source of reducing equivalents for producing fuels. Few robust water-oxidation catalysts capable of mediating this difficult four-electron, four-proton reaction have yet been described. We report a new method for generating an amorphous electrodeposited material, principally consisting of iridium and oxygen, which is a robust and long-lived catalyst for water oxidation, when driven electrochemically. The catalyst material is generated by a simple anodic deposition from Cp*Ir aqua or hydroxo complexes in aqueous solution. This work suggests that organometallic precursors may be useful in electrodeposition of inorganic heterogeneous catalysts.

  1. On-Surface Observation of the Formation of Organometallic Complex in a Supramolecular Network.

    PubMed

    Li, Yibao; Cheng, Linxiu; Liu, Chunhua; Liu, Wei; Fan, Yulan; Fan, Xiaolin; Zeng, Qingdao

    2015-01-01

    The on-surface formation of organometallic monomers or oligomers, especially in supramolecular network, attracts an extensive interest for chemists and material scientist. In this work, we have investigated metal coordination between zinc (II) phthalocyanine (ZnPc) and 1, 3-di (4-pyridyl) propane (dipy-pra) in the 2, 6, 11-tricarboxydecyloxy-3, 7, 10-triundecyloxy triphenylene (asym-TTT) supramolecular template by means of scanning tunneling microscopy (STM) on highly oriented pyrolytic graphite (HOPG) substrate under ambient conditions. The experimental results demonstrate that every two ZnPc molecules in one nano-reactor connect with each other through one dipy-pra molecule by metal-coordination interaction. In this coordinating process, the template of asym-TTT supramolecular networks plays a significant role. PMID:26061532

  2. Quantum Monte Carlo study of charged transition-metal organometallic cluster systems

    NASA Astrophysics Data System (ADS)

    Tokar, Kamil; Derian, Rene; Stich, Ivan

    2015-03-01

    Using accurate fixed-node quantum Monte Carlo (QMC) methods we study 1D clusters formed by transition metal atoms separated by benzene molecules (TMBz), both positively and negatively charged. TMBz are among the most important π-bonded organometallics, which, however, often require charged states for experimental studies. We have performed a systematic study of ground-sate spin multiplets, ionization potentials, electron affinities, and dissociation energies of vanadium-benzene cationic and anionic half- and full-sandwiches. By comparison of QMC and DFT results, we find a very strong impact of electronic correlation on properties of these systems, such as dissociation energies, where ~1 eV energy corrections are found. In particular, the anions are unstable at the DFT level and are stabilized only at the QMC level after sophisticated optimization of the trial wavefunction. Supported by APVV-0207-11 and VEGA (2/0007/12) projects.

  3. Computational Estimate of the Photophysical Capabilities of Four Series of Organometallic Iron(II) Complexes.

    PubMed

    Dixon, Isabelle M; Boissard, Gauthier; Whyte, Hannah; Alary, Fabienne; Heully, Jean-Louis

    2016-06-01

    In this study, we examine a large range of organometallic iron(II) complexes with the aim of computationally identifying the most promising ones in terms of photophysical properties. These complexes combine polypyridine, bis(phosphine), and carbon-bound ligands. Density functional theory has allowed us to establish a comparative Jablonski diagram displaying the lowest singlet, triplet, and quintet states. All of the proposed FeN5C or FeN3P2C complexes unfavorably possess a lowest triplet state of metal-centered (MC) nature. Among the FeN4C2 and FeN2P2C2 series, the carbene complexes display the least favorable excited-state distribution, also having a low-lying (3)MC state. Validating our design strategy, we are now able to propose seven iron(II) complexes displaying a lowest excited state of triplet metal-to-ligand charge-transfer nature. PMID:27228301

  4. Organometallic Complexes Anchored to Conductive Carbon for Electrocatalytic Oxidation of Methane at Low Temperature.

    PubMed

    Joglekar, Madhura; Nguyen, Vinh; Pylypenko, Svitlana; Ngo, Chilan; Li, Quanning; O'Reilly, Matthew E; Gray, Tristan S; Hubbard, William A; Gunnoe, T Brent; Herring, Andrew M; Trewyn, Brian G

    2016-01-13

    Low-temperature direct methane fuel cells (DMEFCs) offer the opportunity to substantially improve the efficiency of energy production from natural gas. This study focuses on the development of well-defined platinum organometallic complexes covalently anchored to ordered mesoporous carbon (OMC) for electrochemical oxidation of methane in a proton exchange membrane fuel cell at 80 °C. A maximum normalized power of 403 μW/mg Pt was obtained, which was 5 times higher than the power obtained from a modern commercial catalyst and 2 orders of magnitude greater than that from a Pt black catalyst. The observed differences in catalytic activities for oxidation of methane are linked to the chemistry of the tethered catalysts, determined by X-ray photoelectron spectroscopy. The chemistry/activity relationships demonstrate a tangible path for the design of electrocatalytic systems for C-H bond activation that afford superior performance in DMEFC for potential commercial applications. PMID:26492385

  5. Reactivity of seventeen- and nineteen-valence electron complexes in organometallic chemistry

    NASA Technical Reports Server (NTRS)

    Stiegman, Albert E.; Tyler, David R.

    1986-01-01

    A guideline to the reactivity of 17- and 19-valence electron species in organometallic chemistry is proposed which the authors believe will supersede all others. The thesis holds that the reactions of 17-electron metal radicals are associatively activated with reactions proceeding through a 19-valence electron species. The disparate reaction chemistry of the 17-electron metal radicals are unified in terms of this associative reaction pathway, and the intermediacy of 19-valence electron complexes in producing the observed products is discussed. It is suggested that related associatively activated pathways need to be considered in some reactions that are thought to occur by more conventional routes involving 16- and 18-electron intermediates. The basic reaction chemistry and electronic structures of these species are briefly discussed.

  6. The Effect of CeO2 Addition on the Microstructure and Properties of Ni-Based Flame-Spray Coatings

    NASA Astrophysics Data System (ADS)

    Zhang, Zhenyu; Liang, Bunv; Guo, Hongjian

    2014-04-01

    Ni-based alloy with different amount of CeO2 powders were flame sprayed and melted onto 1045 carbon steel substrate. Microstructure and properties of the coatings were studied by XRD, field emission gun scanning electron microscope (FEGSEM) and SEM analyses. The wear behavior of the coatings was investigated under dry sliding wear conditions, and was compared with that of the coatings without CeO2, The results show that the microstructure of the coating with CeO2 differs widely from the coating without CeO2, the novel microstructure is beneficial for wear resistance. Abrasive wear tests without lubricant and analysis of the worn surfaces revealed that the Ni-based alloy coatings with the addition of 0.8% CeO2 exhibit higher wear resistance.

  7. Performance of chromia- and alumina-forming Fe- and Ni-base alloys exposed to metal dusting environments: The effect of water vapor and temperature

    DOE PAGESBeta

    Rouaix-Vande Put, Aurelie; Unocic, Kinga A.; Brady, Michael P.; Pint, Bruce A.

    2015-11-18

    Fe- and Ni-base alloys including an alumina-forming austenitic alloy were exposed for 500 h under metal dusting environments with varying temperature, gas composition and total pressure. For one H2–CO–CO2–H2O environment, the increase in temperature from 550 to 750 °C generally decreased metal dusting. When H2O was added to a H2–CO–CO2 environment at 650 °C, the metal dusting attack was reduced. Even after 5000 h at a total pressure of 9.1 atm with 20%H2O, the higher alloyed specimens retained a thin protective oxide. Lastly, for gas mixtures containing little or no H2O, the Fe-base alloys were less resistant to metal dustingmore » than Ni-base alloys.« less

  8. Kinetic Study on the Effect of Chromium Addition to Ni-Based Catalysts for the Steam-CO2 Reforming of Methane.

    PubMed

    Park, Yoon-Hwa; Li, Peng; Moon, Dong-Ju; Park, Nam-Cook; Kim, Young-Chul

    2016-02-01

    In the present work, the kinetic effects of Ni-based catalysts containing various amounts of Cr on the steam-CO2 reforming (SCR) of methane were studied. Kinetic expressions for the SCR of methane over the Ni-based catalysts have been proposed using the power-law rate expression, based on the kinetic data obtained. In addition, the Arrhenius equation was used for calculating the activation energy. Analysis of the data revealed four simple results. Firstly, the partial pressure of CH4 exerts a major influence on the CH4 conversion rates. Secondly, the CH4 conversion rate is inversely proportional to the partial pressure of CO2. Thirdly, the partial pressure of steam has a very slight effect on the reaction rates. Finally, all the catalysts studied have similar apparent activation energies. PMID:27433614

  9. Growth and characterization of an organometallic tri-allylthiourea complex nonlinear optical crystals

    NASA Astrophysics Data System (ADS)

    Perumal, R.; Moorthy Babu, S.

    2008-04-01

    A novel family of allylthiourea metal complexes was identified for photonic applications with allylthiourea serving as a double ligand, and II (B) group metals were chosen as a co-ordination metal. This family belongs to an island-type organometallic category. A series of optically negative nonlinear optical (NLO) crystals (ATCC, ATCB, ATMC and ATMB) have been prepared. Their SHG efficiency was an order of magnitude higher than that of the well-known organic crystal, urea. The properties of allylthiourea complex with central atom Cd were compared with the crystals with another central atom Hg. The latter has longer transparency cut-off wavelength, higher thermal stability and SHG efficiencies. These organometallic tri-allylthiourea complex crystals were grown from the aqueous solution by temperature-lowering technique. Comprehensive studies of synthesis, solubility, crystal growth and the general properties including structural, spectral, optical and thermal properties were analyzed by conducting various characterization techniques. They were synthesized in the de-ionized water and the solubilities of each material were determined by employing thermogravimetric analysis. The growth conditions were analyzed in terms of the pH value of the mother solution because it plays a vital role during the growth. Their structural properties were examined by recording the powder X-ray diffraction pattern. The crystal formation and the metal co-ordination were confirmed by the spectral analysis. The transmission spectrum of these crystals shows a wide transparent UV-vis-NIR band. The thermal behavior of these complexes was studied from the thermal studies. Their NLO efficiencies were analyzed through the Kurt'z technique.

  10. Recent progress in GaInAsSb thermophotovoltaics grown by organometallic vapor phase epitaxy

    SciTech Connect

    Wang, C.A.; Choi, H.K.; Oakley, D.C.; Charache, G.W.

    1998-06-01

    Studies on the materials development of Ga{sub 1{minus}x}In{sub x}As{sub y}Sb{sub 1{minus}y} alloys for thermophotovoltaic (TPV) devices are reviewed. Ga{sub 1{minus}x}In{sub x}As{sub y}Sb{sub 1{minus}y} epilayers were grown lattice matched to GaSb substrates by organometallic vapor phase epitaxy (OMVPE) using all organometallic precursors including triethylgallium, trimethylindium, tertiarybutylarsine, and trimethylantimony with diethyltellurium and dimethylzinc as the n- and p-type dopants, respectively. The overall material quality of these alloys depends on growth temperature, In content, V/III ratio, substrate misorientation, and to a lesser extent, growth rate. A mirror-like surface morphology and room temperature photoluminescence (PL) are obtained for GaInAsSb layers with peak emission in the wavelength range between 2 and 2.5 {micro}m. The crystal quality improves for growth temperature decreasing from 575 to 525 C, and with decreasing In content, as based on epilayer surface morphology and low temperature PL spectra. A trend of smaller full width at half-maximum for low temperature PL spectra is observed as the growth rate is increased from 1.5 to 2.5 and 5 {micro}m/h. In general, GaInAsSb layers grown on (100) GaSb substrates with a 6{degree} toward (111)B misorientation exhibited overall better material quality than layers grown on the more standard substrate (100)2{degree} toward (110). Consistent growth of high performance lattice-matched GaInAsSb TPV devices is also demonstrated.

  11. Organometallic Polymers.

    ERIC Educational Resources Information Center

    Carraher, Charles E., Jr.

    1981-01-01

    Reactions utilized to incorporate a metal-containing moiety into a polymer chain (addition, condensation, and coordination) are considered, emphasizing that these reactions also apply to smaller molecules. (JN)

  12. Effect of variations of cobalt content on the cyclic oxidation resistance of selected Ni-base superalloys

    SciTech Connect

    Barrett, C.A.

    1986-03-01

    Cobalt levels were systematically varied in the Ni-base turbine alloys U-700 (cast), U-700m(PM/HIP), Waspaloy, Mar-M-247, In-738, Nimonic-115, U-720, and SX-R-150. The cobalt levels ranged from 0 wt % to the nominal commercial content in each alloy. The alloys were tested in cyclic oxidation in static air at 1000, 1100 and 1150 C for 500, 200 and 100 hr respectively. An oxidation attack parameter, Ka derived from the specific weight change versus time data was used to evaluate the oxidation behavior of the alloys along with X-ray diffraction analysis of the surface oxides. The alloys tend to form either Cr/sub 2/O/sub 3//chromite spinel or Al/sub 2/O/sub 3//aluminate spinel depending on the CR/Al ratio in the alloys. Alloys with a ratio of 3.5 or higher tend to favor the Cr oxides while those under 3.0 form mostly Al oxides. In general the Al/sub 2/O/sub 3//aluminate spinel forming alloys have the better oxidation resistance. Increased cobalt content lowers the scaling resistance of the higher Cr alloys while a 5.0 wt % Co content is optimum for the Al controlling alloys. The refractory metals, particularly Ta, appear beneficial to both types of oxides perhaps due to the formation of the omni-present trirutile Ni(Ta,Cb,Mo,W)2O6. Both scales break down as increasing amounts of NiO is formed.

  13. Hydrodeoxygenation of prairie cordgrass bio-oil over Ni based activated carbon synergistic catalysts combined with different metals.

    PubMed

    Cheng, Shouyun; Wei, Lin; Zhao, Xianhui; Kadis, Ethan; Cao, Yuhe; Julson, James; Gu, Zhengrong

    2016-06-25

    Bio-oil can be upgraded through hydrodeoxygenation (HDO). Low-cost and effective catalysts are crucial for the HDO process. In this study, four inexpensive combinations of Ni based activated carbon synergistic catalysts including Ni/AC, Ni-Fe/AC, Ni-Mo/AC and Ni-Cu/AC were evaluated for HDO of prairie cordgrass (PCG) bio-oil. The tests were carried out in the autoclave under mild operating conditions with 500psig of H2 pressure and 350°C temperature. The catalysts were characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) and transmission electron microscope (TEM). The results show that all synergistic catalysts had significant improvements on the physicochemical properties (water content, pH, oxygen content, higher heating value and chemical compositions) of the upgraded PCG bio-oil. The higher heating value of the upgraded bio-oil (ranging from 29.65MJ/kg to 31.61MJ/kg) improved significantly in comparison with the raw bio-oil (11.33MJ/kg), while the oxygen content reduced to only 21.70-25.88% from 68.81% of the raw bio-oil. Compared to raw bio-oil (8.78% hydrocarbons and no alkyl-phenols), the Ni/AC catalysts produced the highest content of gasoline range hydrocarbons (C6-C12) at 32.63% in the upgraded bio-oil, while Ni-Mo/AC generated the upgraded bio-oil with the highest content of gasoline blending alkyl-phenols at 38.41%. PMID:26902668

  14. Effects of sintering temperature on the microstructural evolution and wear behavior of WCp reinforced Ni-based coatings

    NASA Astrophysics Data System (ADS)

    Chen, Chuan-hui; Bai, Yang; Ye, Xu-chu

    2014-12-01

    This article focuses on the microstructural evolution and wear behavior of 50wt%WC reinforced Ni-based composites prepared onto 304 stainless steel substrates by vacuum sintering at different sintering temperatures. The microstructure and chemical composition of the coatings were investigated by X-ray diffraction (XRD), differential thermal analysis (DTA), scanning and transmission electron microscopy (SEM and TEM) equipped with energy-dispersive X-ray spectroscopy (EDS). The wear resistance of the coatings was tested by thrust washer testing. The mechanisms of the decomposition, dissolution, and precipitation of primary carbides, and their influences on the wear resistance have been discussed. The results indicate that the coating sintered at 1175°C is composed of fine WC particles, coarse M6C (M=Ni, Fe, Co, etc.) carbides, and discrete borides dispersed in solid solution. Upon increasing the sintering temperature to 1225°C, the microstructure reveals few incompletely dissolved WC particles trapped in larger M6C, Cr-rich lamellar M23C6, and M3C2 in the austenite matrix. M23C6 and M3C2 precipitates are formed in both the γ/M6C grain boundary and the matrix. These large-sized and lamellar brittle phases tend to weaken the wear resistance of the composite coatings. The wear behavior is controlled simultaneously by both abrasive wear and adhesive wear. Among them, abrasive wear plays a major role in the wear process of the coating sintered at 1175°C, while the effect of adhesive wear is predominant in the coating sintered at 1225°C.

  15. Effects of alloying element and temperature on the stacking fault energies of dilute Ni-base superalloys

    NASA Astrophysics Data System (ADS)

    Shang, S. L.; Zacherl, C. L.; Fang, H. Z.; Wang, Y.; Du, Y.; Liu, Z. K.

    2012-12-01

    A systematic study of stacking fault energy (γSF) resulting from induced alias shear deformation has been performed by means of first-principles calculations for dilute Ni-base superalloys (Ni23X and Ni71X) for various alloying elements (X) as a function of temperature. Twenty-six alloying elements are considered, i.e., Al, Co, Cr, Cu, Fe, Hf, Ir, Mn, Mo, Nb, Os, Pd, Pt, Re, Rh, Ru, Sc, Si, Ta, Tc, Ti, V, W, Y, Zn, and Zr. The temperature dependence of γSF is computed using the proposed quasistatic approach based on a predicted γSF-volume-temperature relationship. Besides γSF, equilibrium volume and the normalized stacking fault energy (ΓSF = γSF/Gb, with G the shear modulus and b the Burgers vector) are also studied as a function of temperature for the 26 alloying elements. The following conclusions are obtained: all alloying elements X studied herein decrease the γSF of fcc Ni, approximately the further the alloying element X is from Ni on the periodic table, the larger the decrease of γSF for the dilute Ni-X alloy, and roughly the γSF of Ni-X decreases with increasing equilibrium volume. In addition, the values of γSF for all Ni-X systems decrease with increasing temperature (except for Ni-Cr at higher Cr content), and the largest decrease is observed for pure Ni. Similar to the case of the shear modulus, the variation of γSF for Ni-X systems due to various alloying elements is traceable from the distribution of (magnetization) charge density: the spherical distribution of charge density around a Ni atom, especially a smaller sphere, results in a lower value of γSF due to the facility of redistribution of charges. Computed stacking fault energies and the related properties are in favorable accord with available experimental and theoretical data.

  16. Crystal and molecular structures of selected organic and organometallic compounds and an algorithm for empirical absorption correction

    SciTech Connect

    Karcher, B.

    1981-10-01

    Cr(CO)/sub 5/(SCMe/sub 2/) crystallizes in the monoclinic space group P2/sub 1//a with a = 10.468(8), b = 11.879(5), c = 9.575(6) A, and ..beta.. = 108.14(9)/sup 0/, with an octahedral coordination around the chromium atom. PSN/sub 3/C/sub 6/H/sub 12/ crystallizes in the monoclinic space group P2/sub 1//n with a = 10.896(1), b = 11.443(1), c = 7.288(1) A, and ..beta.. = 104.45(1)/sup 0/. Each of the five-membered rings in this structure contains a carbon atom which is puckered toward the sulfur and out of the nearly planar arrays of the remaining ring atoms. (RhO/sub 4/N/sub 4/C/sub 48/H/sub 56/)/sup +/(BC/sub 24/H/sub 20/)/sup -/.1.5NC/sub 2/H/sub 3/ crystallizes in the triclinic space group P1 with a = 17.355(8), b = 21.135(10), c = 10.757(5) A, ..cap alpha.. = 101.29(5), ..beta.. = 98.36(5), and ..gamma.. = 113.92(4)/sup 0/. Each Rh cation complex is a monomer. MoP/sub 2/O/sub 10/C/sub 16/H/sub 22/ crystallizes in the monoclinic space group P2/sub 1//c with a = 12.220(3), b = 9.963(2), c = 20.150(6) A, and ..beta.. = 103.01(3)/sup 0/. The molybdenum atom occupies the axial position of the six-membered ring of each of the two phosphorinane ligands. An empirical absorption correction program was written.

  17. Speciation of inorganic and organometallic compounds in solid biological samples by thermal vaporization and plasma emission spectrometry

    SciTech Connect

    Hanamura, S.; Smith, B.W.; Winefordner, J.D.

    1983-11-01

    By means of thermal vaporization, inorganic, organic, and metallorganic species are separated and elemental emission in a microwave plasma is detected as a function of vaporization temperature. Solid samples of 250 mg or more are used to avoid problems with sample heterogeneity. The precision of characteristic appearance temperatures is +/-2/sup 0/C. The single electrode atmosphere pressure microwave plasma system is extremely tolerant to the introduction of water, organic solvents, and air. The measurement system contained a repetition wavelength scan device to allow background correction. The plasma temperature was 5500 K. The system was used to measure C, H, N, O, and Hg in orchard leaves and in tuna fish. 9 figures, 5 tables.

  18. NMR studies in chemistry. I. Organometallic tin and geramanium compounds. II. The sorbitol pathway in intact lenses

    SciTech Connect

    Williams, W.F.

    1985-01-01

    Nuclear magnetic resonance spectroscopy has been utilized in the study of two very different chemical problems. The bonding and structure of various cyclopropyl derivatives of tin and germanium has been investigated by means of Sn-119, Ge-73, C-13, and H-1 NMR spectroscopy. Intact rabbit lenses have also been studied using NMR spectroscopy with regard to diabetic cataract formation. C-13 and P-31 NMR spectroscopies have been utilized in the study of the sorbitol pathway and aldose reductase inhibition.

  19. Deformation-phase transformation coupling mechanism of white layer formation in high speed machining of FGH95 Ni-based superalloy

    NASA Astrophysics Data System (ADS)

    Du, Jin; Liu, zhanqiang; Lv, Shaoyu

    2014-02-01

    Ni-based superalloy represents a significant metal portion of the aircraft critical structural and engine components. When these critical structural components in aerospace industry are manufactured with the objective to reach high reliability levels and excellent service performance, surface integrity is one of the most relevant parameter used for evaluating the quality of finish machined surfaces. In the study of surface integrity, the formation white layer is a very important research topic. The formation of white layer on the Ni-based superalloy machined surface will reduce the machined parts service performance and fatigue life. This paper was conducted to determine the effects of cutting speed on white layer formation in high speed machining of FGH95 Ni-based superalloy. Optical microscope, scanning electron microscope and X-ray diffraction were employed to analyze the elements and microstructures of white layer and bulk materials. The statistical analysis for grain numbers was executed to study the influence of cutting speed on the grain refinement in the machined surface. The investigation results showed that white layer exhibits significantly different microstructures with the bulk materials. It shows densification, no obvious structural features characteristic. The microstructure and phase of Ni-based solid solution changed during cutting process. The increase of cutting speed causes the increase of white layer thickness when the cutting speed is less than 2000 m/min. However, white layer thickness reduces with the cutting speed further increase. The higher the cutting speed, the more serious grains refinement in machined surface. 2-D FEM for machining FGH95 were carried out to simulate the cutting process and obtained the cutting temperature field, cutting strain field and strain rate field. The impact mechanisms of cutting temperature, cutting strain and strain rates on white layer formation were analyzed. At last, deformation-phase transformation

  20. Compound matrices

    NASA Astrophysics Data System (ADS)

    Kravvaritis, Christos; Mitrouli, Marilena

    2009-02-01

    This paper studies the possibility to calculate efficiently compounds of real matrices which have a special form or structure. The usefulness of such an effort lies in the fact that the computation of compound matrices, which is generally noneffective due to its high complexity, is encountered in several applications. A new approach for computing the Singular Value Decompositions (SVD's) of the compounds of a matrix is proposed by establishing the equality (up to a permutation) between the compounds of the SVD of a matrix and the SVD's of the compounds of the matrix. The superiority of the new idea over the standard method is demonstrated. Similar approaches with some limitations can be adopted for other matrix factorizations, too. Furthermore, formulas for the n - 1 compounds of Hadamard matrices are derived, which dodge the strenuous computations of the respective numerous large determinants. Finally, a combinatorial counting technique for finding the compounds of diagonal matrices is illustrated.

  1. Unusually Strong Long-Distance Metal-Metal Coupling in Bis(ferrocene)-Containing BOPHY: An Introduction to Organometallic BOPHYs.

    PubMed

    Rhoda, Hannah M; Chanawanno, Kullapa; King, Alexander J; Zatsikha, Yuriy V; Ziegler, Christopher J; Nemykin, Victor N

    2015-12-01

    The first organometallic BOPHY (BOPHY=bis(difluoroboron)-1,2-bis{(pyrrol-2-yl)methylene}hydrazine) containing two ferrocene substituents was prepared through a Knoevenagel condensation between tetramethyl substituted BOPHY and ferrocene carboxaldehyde. An unprecedentedly strong long-range (≈17.2 Å) metal-metal coupling in this new complex was investigated using electrochemical, spectroelectrochemical, and chemical oxidation methods. Electrochemical data is indicative of a 200 mV separation between the first and the second ferrocene-centered oxidation processes. Formation of the mixed-valence states and appearance and disappearance of two NIR bands were observed during stepwise oxidation of the first organometallic BOPHY. The electronic structure and the nature of the excited states in this new chromophore were studied by DFT and TDDFT calculations. PMID:26449288

  2. Search for the ground-state electronic configurations of correlated organometallic metallocenes from constraint density functional theory

    NASA Astrophysics Data System (ADS)

    Nawa, Kenji; Kitaoka, Yukie; Nakamura, Kohji; Imamura, Hiroshi; Akiyama, Toru; Ito, Tomonori; Weinert, M.

    2016-07-01

    The ground-state electronic configurations of the correlated organometallic metallocenes, M Cp2,M =V , Cr, Mn, Fe, Co, and Ni, are investigated using constraint density functional theory combined with nonempirical Ueff parameters determined from linear-response theory. The relative stability of the various d -orbital electronic configurations of these organometallic molecules is found to be sensitive to the amount of correlation. Using nonempirical values of Ueff, the calculated electronic configurations are in agreement with the experiments: 4A2 g ,3E2 g ,6A1 g ,1A1 g ,2E1 g , and 3A2 g for the VCp2,CrCp2,MnCp2,FeCp2,CoCp2 , and NiCp2, respectively.

  3. 'Clickable' ZnO nanocrystals: the superiority of a novel organometallic approach over the inorganic sol-gel procedure.

    PubMed

    Grala, Agnieszka; Wolska-Pietkiewicz, Małgorzata; Danowski, Wojciech; Wróbel, Zbigniew; Grzonka, Justyna; Lewiński, Janusz

    2016-05-31

    We demonstrate for the first time a highly efficient Cu(i)-catalyzed alkyne-azide cycloaddition reaction on the surface of ZnO nanocrystals with retention of their photoluminescence properties. Our comparative studies highlight the superiority of a novel self-supporting organometallic method for the preparation of brightly luminescent and well-passivated ZnO nanocrystals over the traditional sol-gel procedure. PMID:27156855

  4. Facile synthesis of one-dimensional organometallic-organic hybrid polymers based on a diphosphorus complex and flexible bipyridyl linkers.

    PubMed

    Elsayed Moussa, M; Attenberger, B; Peresypkina, E V; Fleischmann, M; Balázs, G; Scheer, M

    2016-08-21

    The selective synthesis of a series of new "ladderlike" one-dimensional organometallic-organic hybrid polymers is shown. The polymers are obtained from the reaction of the diphosphorus ligand complex [Cp2Mo2(CO)4(η(2)-P2)] with the copper salt [Cu(CH3CN)4]BF4 in the presence of flexible organic bipyridyl linkers in high selectivity. This unique behaviour is supported by DFT calculations. PMID:27444554

  5. Supported f-element organometallic complexes surface chemistry and catalysis: Technical progress report, March 15, 1987-December 28, 1987

    SciTech Connect

    Marks, T.J.; Burwell, R.L. Jr.

    1987-01-01

    The goal of this research program is to understand how the reactivity of organometallic molecules is dramatically altered by adsorption on inorganic supports such as ..gamma..-alumina, silica, magnesium chloride, etc. While the initial focus of this research concerned the catalytic properties of organoactinides adsorbed on alumina, the effort has now expanded in a number of new directions. These include new supports, new surface spectroscopic techniques, detailed studies of reaction kinetics, new metals, and new connections with solution chemistry.

  6. Antibacterial properties and mode of action of new triaryl butene citrate compounds.

    PubMed

    El Arbi, Mehdi; Théolier, Jérémie; Pigeon, Pascal; Jellali, Karim; Trigui, Fatma; Top, Siden; Aifa, Sami; Fliss, Ismail; Jaouen, Gérard; Hammami, Riadh

    2014-04-01

    The aim of this study was to evaluate the antibacterial activity of newly synthesized triaryl butene analogues of tamoxifen. Several compounds were synthesized and converted to citrate salts to ensure greater solubility. Four compounds showed significant antibacterial activity at micromolar concentrations against Gram-positive and Gram-negative foodborne pathogens including Listeria monocytogenes, Listeria ivanovii, Enterococcus faecalis, Staphylococcus aureus and Escherichia coli. Two compounds at 50 μM, caused only 7.8 and 11% hemolysis. One of these as well as the remaining two caused high K(+) and Na(+) efflux from bacterial cells. Ultrastructural alterations were also visible using transmission electron microscopy, which revealed severe damage of the inner or outer membrane of E. coli. L. ivanovii showed swelling, corrugations and similar damage indicating a loss of cell-wall integrity. Organometallic compounds may offer interesting opportunities for the design of novel classes of antimicrobial compounds. PMID:24602786

  7. Effects of alloying element and temperature on the stacking fault energies of dilute Ni-base superalloys.

    PubMed

    Shang, S L; Zacherl, C L; Fang, H Z; Wang, Y; Du, Y; Liu, Z K

    2012-12-19

    A systematic study of stacking fault energy (γ(SF)) resulting from induced alias shear deformation has been performed by means of first-principles calculations for dilute Ni-base superalloys (Ni(23)X and Ni(71)X) for various alloying elements (X) as a function of temperature. Twenty-six alloying elements are considered, i.e., Al, Co, Cr, Cu, Fe, Hf, Ir, Mn, Mo, Nb, Os, Pd, Pt, Re, Rh, Ru, Sc, Si, Ta, Tc, Ti, V, W, Y, Zn, and Zr. The temperature dependence of γ(SF) is computed using the proposed quasistatic approach based on a predicted γ(SF)-volume-temperature relationship. Besides γ(SF), equilibrium volume and the normalized stacking fault energy (Γ(SF) = γ(SF)/Gb, with G the shear modulus and b the Burgers vector) are also studied as a function of temperature for the 26 alloying elements. The following conclusions are obtained: all alloying elements X studied herein decrease the γ(SF) of fcc Ni, approximately the further the alloying element X is from Ni on the periodic table, the larger the decrease of γ(SF) for the dilute Ni-X alloy, and roughly the γ(SF) of Ni-X decreases with increasing equilibrium volume. In addition, the values of γ(SF) for all Ni-X systems decrease with increasing temperature (except for Ni-Cr at higher Cr content), and the largest decrease is observed for pure Ni. Similar to the case of the shear modulus, the variation of γ(SF) for Ni-X systems due to various alloying elements is traceable from the distribution of (magnetization) charge density: the spherical distribution of charge density around a Ni atom, especially a smaller sphere, results in a lower value of γ(SF) due to the facility of redistribution of charges. Computed stacking fault energies and the related properties are in favorable accord with available experimental and theoretical data. PMID:23172684

  8. Design of Ni-base superalloys and MCrAlY coatings from first-principles and computational thermodynamics

    NASA Astrophysics Data System (ADS)

    Liu, Xuan

    This thesis explores the thermodynamics of Ni-base superalloys and metallic coatings used in the protection of these alloys. First, a thermodynamic description of the Nb-Re binary system is developed by means of the CALculation of PHAse Diagrams (CALPHAD) method supplemented by first-principles calculations based on density functional theory (DFT) and experimental data in the literature. In addition to terminal solution phases in the Nb-Re system, there are two intermetallic phases, sigma (sigma) and chi (chi), all modeled with sublattice models. Special quasi-random structures (SQS) are employed to mimic the random mixing of the bcc, hcp, and fcc solid solution phases from first-principles. Finite temperature thermodynamic properties of end-members and dilute mixing in each sublattice of the complex sigma and chi phases are predicted from first-principles calculations and the Debye-Gruneisen model. The utility of the Debye-Gruneisen model is then investigated with respect to its fitting parameter known as the scaling factor, and it is found that the prediction of finite-temperature properties can be improved by modification of this factor. This scaling factor is studied using bcc, fcc, hcp systems and the Mg-Zn binary system due to the abundance of thermodynamic data. Predicted Debye temperatures (thetaD), using a calculated scaling factor, show good agreement with experiments and improvements over the scaling factor derived by Moruzzi et al. Finite-temperature thermodynamic properties of intermetallics are investigated to show the efficiency and improved accuracy of the calculated scaling factor. However, for the intermetallic Mg2Zn11, the Debye-Gruneisen model cannot account for anomalous lattice dynamics at low temperatures. The calculated scaling factor is then used throughout the present work for finite-temperature predictions. Another missing piece of the literature includes the thermodynamics of Al-Co-Cr-Ni bond coat system used in the protection of

  9. Organometallically Anisotropic Growth of Ultralong Sb2Se3 Nanowires with Highly Enhanced Photothermal Response.

    PubMed

    Chen, Guihuan; Zhou, Jun; Zuo, Jian; Yang, Qing

    2016-02-01

    Ultralong orthorhombic Sb2Se3 nanowires have been successfully fabricated via an alternative facile organometallic synthetic route from the reaction of triphenylantimony(III) with dibenzyldiselenide in oleylamine at 180-240 °C without any other additives. The formation and growth mechanism of the Sb2Se3 nanowires is intensively investigated, and it is found that the anisotropic growth of the nanowires with almost constant diameters is resulted from the synergistic effects of the intrinsic property of the orthorhombic crystal structure and the weak binding assistance of oleylamine, and the length of the nanowires can be elongated easily by increasing reaction time in the synthetic route. Moreover, the photothermal response of the Sb2Se3 nanowires is first evaluated under illumination of UV light (320-390 nm), and it is especially noted that the Sb2Se3 nanowires exhibit highly enhanced photothermal responses (more than two times the intensity) as compared to the bulk Sb2Se3. In addition, the Sb2Se3 nanowires show excellent light-to-heat performance, which is superior to that of the nanostructured titanium dioxide and silicon powder under the same conditions. PMID:26744773

  10. Atmospheric pressure synthesis of photoluminescent hybrid materials by sequential organometallic vapor infiltration into polyethylene terephthalate fibers

    SciTech Connect

    Akyildiz, Halil I.; Mousa, Moataz Bellah M.; Jur, Jesse S.

    2015-01-28

    Exposing a polymer to sequential organometallic vapor infiltration (SVI) under low pressure conditions can significantly modify the polymer's chemical, mechanical, and optical properties. We demonstrate that SVI of trimethylaluminum into polyethylene terephthalate (PET) can also proceed readily at atmospheric pressure, and at 60 °C the extent of reaction determined by mass uptake is independent of pressure between 2.5 Torr and 760 Torr. At 120 °C, however, the mass gain is 50% larger at 2.5 Torr relative to that at 760 Torr, indicating that the precursor diffusion in the chamber and fiber matrix decreases at higher source pressure. Mass gain decreases, in general, as the SVI process temperature increases both at 2.5 Torr and 760 Torr attributed to the faster reaction kinetics forming a barrier layer, which prevents further diffusion of the reactive species. The resulting PET/Al-O{sub x} product shows high photoluminescence compared to untreated fibers. A physical mask on the polymer during infiltration at 760 Torr is replicated in the underlying polymer, producing an image in the polymer that is visible under UV illumination. Because of the reduced precursor diffusivity during exposure at 760 Torr, the image shows improved resolution compared to SVI performed under typical 2.5 Torr conditions.

  11. Electronic and magnetic properties of silicon supported organometallic molecular wires: a density functional theory (DFT) study.

    PubMed

    Liu, Xia; Tan, Yingzi; Li, Xiuling; Wu, Xiaojun; Pei, Yong

    2015-08-28

    The electronic and magnetic properties of transition metal (TM = Sc, Ti, V, Cr and Mn) atom incorporated single and double one-dimensional (1D) styrene molecular wires confined on the hydrogen-terminated Si(100) surface are explored for the first time by means of spin-polarized density functional theory, denoted as Si-[TM(styrene)]. It is unveiled that TM atoms bind asymmetrically to the adjacent phenyl rings, which leads to novel electronic and magnetic properties in stark contrast to the well-studied gas phase TM-benzene molecular wires. Si-[Mn(styrene)]∞ and Si-[Cr(styrene)]∞ single molecular wires (SMWs) are a ferromagnetic semiconductor and half metal, respectively. Creation of H-atom defects on the silicon surface can introduce an impurity metallic band, which leads to novel half-metallic magnetism of a Si-[Mn(styrene)]∞ system. Moreover, double molecular wires (DMWs) containing two identical or hetero SMWs are theoretically designed. The [Mn(styrene)]∞-[Cr(styrene)]∞ DMW exhibits half-metallic magnetism where the spin-up and spin-down channels are contributed by two single molecular wires. Finally, we demonstrate that introducing a TM-defect may significantly affect the electronic structure and magnetic properties of molecular wires. These studies provide new insights into the structure and properties of surface supported 1-D sandwiched molecular wires and may inspire the future experimental synthesis of substrate confined organometallic sandwiched molecular wires. PMID:26219748

  12. Organometallic Probe for the Electronics of Base-Stabilized Group 11 Metal Cations.

    PubMed

    Braunschweig, Holger; Ewing, William C; Kramer, Thomas; Mattock, James D; Vargas, Alfredo; Werner, Christine

    2015-08-24

    A number of trimetalloborides have been synthesized through the reactions of base-stabilized coinage metal chlorides with a dimanganaborylene lithium salt in the hope of using this organometallic platform to compare and evaluate the electronics of these popular coinage metal fragments. The adducts of Cu(I), Ag(I), and Au(I) ions, stabilized by tricyclohexylphosphine (PCy3), N-1,3-bis(4-methylphenyl)imidazol-2-ylidene (ITol), or 1-(2,6-diisopropylphenyl)-3,3,5,5-tetramethylpyrrolidin-2-ylidene (CAAC), with [{Cp(CO)2Mn}2B](-) were studied spectroscopically, structurally, and computationally. The geometries of the adducts fall into two classes, one symmetric and one asymmetric, each relying on the combined characteristics of both the metal and ligand. The energetic factors proposed as the causes of the structural differences were investigated by ETS-NOCV (extended transition state-natural orbitals for chemical valence) analysis, which showed the final geometry to be controlled by the competition between the tendency of the coinage metal to adopt a higher or lower coordination number and the willingness of the cationic fragment to participate in back-bonding interactions. PMID:26178571

  13. Strong magnetic interactions through weak bonding interactions in organometallic radicals: combined experimental and theoretical study.

    PubMed

    Cauchy, Thomas; Ruiz, Eliseo; Jeannin, Olivier; Nomura, Mitsushiro; Fourmigué, Marc

    2007-01-01

    The magnetic properties of a series of three neutral radical organometallic complexes of general formula [CpNi(dithiolene)]. have been investigated by a combination of X-ray crystal structure analysis and magnetic susceptibility measurements, while the assignment of the exchange coupling constants to the possible exchange pathways has been accomplished with the help of calculations based on density functional theory (DFT). The syntheses and X-ray structures of [CpNi(adt)] (adt=acrylonitrile-2,3-dithiolate) and [CpNi(tfd)] (tfd=1,2-bis(trifluoromethyl)ethene-1,2-dithiolate) complexes are described, while [CpNi(mnt)] (mnt=maleonitriledithiolate) was reported earlier. In the three complexes, we observed strong antiferromagnetic coupling that could not be explained solely by short SS intermolecular contacts. Our calculations indicated that spin density in these complexes is strongly delocalized on the NiS2 moiety, with up to 20% on the Cp ring. As a consequence, CpCp and Cpdithiolene overlap interactions have been identified as responsible for antiferromagnetic couplings. The [CpNi(adt)] complex thus has a value J=-369.5 cm(-1) for an exchange interaction through a pi stacking due to the CpCp overlap. PMID:17661321

  14. Preparation of nanocrystalline metal oxides and intermetallic phases by controlled thermolysis of organometallic coordination polymers

    NASA Astrophysics Data System (ADS)

    Rehbein, Marcus; Epple, Matthias; Fischer, R. Dieter

    2000-06-01

    Organometallic coordination polymers of the super-Prussian blue type [(Me 3Sn) nM(CN) 6] (Me=CH 3; n=3, 4; M=Fe, Co, Ru) were subjected to thermolysis in different atmospheres (air, argon, hydrogen/nitrogen). In air, oxides were found: Fe 2O 3/SnO 2 (crystalline and nanocrystalline), Co 2SnO 4 and RuO 2. In argon and in hydrogen, the intermetallic phases FeSn 2, CoSn 2, Ru 3Sn 7 and Fe 3SnC were obtained. A detailed mechanistic study was carried out using thermogravimetry (TG), X-ray diffraction (XRD), X-ray absorption spectroscopy (EXAFS) at Fe, Co, Ru and Sn K-edges, infrared spectroscopy (IR) and elemental analysis. Below 250°C, Me 3SnCN and (CN) 2 are released, whereas above 250°C oxidation or pyrolysis leads to the corresponding oxides or intermetallic phases. Polymeric cyanides containing at least two metals have turned out to be suitable precursors to prepare well-defined oxides and intermetallic phases at comparatively low temperature.

  15. Elucidation of the organometallic vapor phase epitaxial growth mechanism for InP

    NASA Technical Reports Server (NTRS)

    Buchan, N. I.; Larsen, C. A.; Stringfellow, G. B.

    1987-01-01

    A new technique for tracing the organometallic vapor epitaxial growth is reported. The pyrolysis of PH3, alone and in the presence of trimethylindium (TMIn), and of TMIn alone was studied by conducting the epitaxial growth of InP in D2 as the carrier gas, tracing growth reactions by mass spectrometric analysis of the product molecules. The TMIn alone pyrolyzes mostly homogeneously in the gas phase, while the PH3 pyrolysis is completely heterogeneous at the InP surface. Adding TMIn to PH3 results in a dramatic decrease in the pyrolysis temperature. PH3 molecules which interact with TMIn in the gas phase pyrolyze at temperatures as low as 250, and those decomposing without TMIn interaction pyrolyze at temperatures approximately 200 C higher. Similarly, the presence of PH3 lowers the TMIn pyrolysis temperature by at least 50 C. TMIn alone in D2 produces mainly CH3D molecules. For high PH3:TMIn ratios, CH4 is the only carbon-containing reaction product.

  16. InAsBi alloys grown by organometallic vapor phase epitaxy

    NASA Astrophysics Data System (ADS)

    Huang, K. T.; Chiu, C. T.; Cohen, R. M.; Stringfellow, G. B.

    1993-11-01

    InAsBi is a III/V alloy with potential application for detectors in the 8-12 μm region of the spectrum. Growth of InAs 1- xBi x, with x ≤ 0.054, at 350°C by atmospheric pressure organometallic vapor phase epitaxy has been made possible by using a new combination of precursors, ethyldimethylindium (EDMIn), tertiarybutylarsine (TBAs) and trimethylbismuth (TMBi). Results were obtained using a V/III ratio between 21 and 22. With these conditions, a Bi distribution coefficient of 1.746 was measured. X-ray diffraction verifies that Bi incorporates substitutionally into the zincblende structure. For x < 0.045, it was possible to suppress whisker formation and obtain excellent surface morphology. Measurement of photoluminescence for x ≤ 0.037 indicates good crystal quality. The measured rate of change of bandgap with Bi concentration, d Eg/d x = -55 meV/%Bi, indicates that a 77 K bandgap energy of E = 0.10 eV should be reached with an alloy composition of InAs 0.94Bi 0.06.

  17. Study of surface relief gratings on azo organometallic films in picosecond regime.

    PubMed

    Luc, J; Bouchouit, K; Czaplicki, R; Fillaut, J-L; Sahraoui, B

    2008-09-29

    Materials for optical data storage and optical information processing must exhibit good holographic properties. Many materials for these applications have been already proposed. Here we describe a grating inscription process characterized by short inscription time and long-time stability. A series of ruthenium-acetylide organometallic complexes containing an azobenzene fragment were synthesized. Photo-induced gratings were produced by short pulse (16 ps, 532 nm) laser irradiation. The surface relief gratings formed at the same time were observed by atomic force microscope. In this work, we highlight the short inscription times brought into play as well as the good temporal stability of these gratings stored at room temperature. We study the influence of the polarization states and the light intensity of writing beams on the dynamics of the surface relief gratings formation and we compare these results with those of a known representative of azobenzene derivative (Disperse Red 1). Lastly, we show that it is possible to write two-dimensional surface relief gratings. PMID:18825202

  18. p-type Mesoscopic Nickel Oxide/Organometallic Perovskite Heterojunction Solar Cells

    PubMed Central

    Wang, Kuo-Chin; Jeng, Jun-Yuan; Shen, Po-Shen; Chang, Yu-Cheng; Diau, Eric Wei-Guang; Tsai, Cheng-Hung; Chao, Tzu-Yang; Hsu, Hsu-Cheng; Lin, Pei-Ying; Chen, Peter; Guo, Tzung-Fang; Wen, Ten-Chin

    2014-01-01

    In this article, we present a new paradigm for organometallic hybrid perovskite solar cell using NiO inorganic metal oxide nanocrystalline as p-type electrode material and realized the first mesoscopic NiO/perovskite/[6,6]-phenyl C61-butyric acid methyl ester (PC61BM) heterojunction photovoltaic device. The photo-induced transient absorption spectroscopy results verified that the architecture is an effective p-type sensitized junction, which is the first inorganic p-type, metal oxide contact material for perovskite-based solar cell. Power conversion efficiency of 9.51% was achieved under AM 1.5 G illumination, which significantly surpassed the reported conventional p-type dye-sensitized solar cells. The replacement of the organic hole transport materials by a p-type metal oxide has the advantages to provide robust device architecture for further development of all-inorganic perovskite-based thin-film solar cells and tandem photovoltaics. PMID:24755642

  19. Magnetically-induced electric polarization in an organo-metallic magnet

    SciTech Connect

    Zapf, W S; Fabris, F W; Balakirev, F F; Francoual, S M; Kenzelmann, M; Chen, Y

    2009-01-01

    The coupling between magnetic order and ferroelectricity has been under intense investigation in a wide range of transition metal oxides. The strongest coupling is obtained in so-called magnetically induced multiferroics where ferroelectricity arises directly from magnetic order that breaks inversion symmetry. However, it has been difficult to find non-oxide based materials in which these effects occur. Here we present a study of copper dimethyl sulfoxide dichloride (CDC), an organometallic quantum magnet containing S =1/1 Cu spins, in which a switchable electric polarization arises from field-tuned magnetic order. Fast magnetic field pulses allow us to perform sensitive measurements of the electric polarization and demonstrate that the electric state is present only if the magnetic order is non-collinear. Furthermore, we show that the electric polarization can be switched in a stunning hysteretic fashion. Because the magnetic order in CDC is mediated by large organic molecules, our study shows that magnetoelectric interactions can exist in this important class of materials, opening the road to designing magnetoelectrics and multiferroics using large molecules as building blocks. Further, we demonstrate that CDC undergoes a magnetoelectric quantum phase transition -the first of its kind, where both ferroelectric and magnetic order emerge simultaneously as a function of magnetic field at very low temperatures.

  20. Time resolved infrared studies of C-H bond activation by organometallics

    SciTech Connect

    Asplund, M.C. |

    1998-06-01

    This work describes how step-scan Fourier Transform Infrared spectroscopy and visible and near infrared ultrafast lasers have been applied to the study of the photochemical activation of C-H bonds in organometallic systems, which allow for the selective breaking of C-H bonds in alkanes. The author has established the photochemical mechanism of C-H activation by Tp{sup *}Rh(CO){sub 2}(Tp{sup *} = HB-Pz{sup *}{sub 3}, Pz = 3,5-dimethylpyrazolyl) in alkane solution. The initially formed monocarbonyl forms a weak solvent complex, which undergoes a change in Tp{sup *} ligand connectivity. The final C-H bond breaking step occurs at different time scales depending on the structure of the alkane. In linear solvents, the time scale is <50 ns and cyclic alkanes is {approximately}200 ps. The reactivity of the Tp{sup *}Rh(CO){sub 2} system has also been studied in aromatic solvents. Here the reaction proceeds through two different pathways, with very different time scales. The first proceeds in a manner analogous to alkanes and takes <50 ns. The second proceeds through a Rh-C-C complex, and takes place on a time scale of 1.8 {micro}s.

  1. 3D ordered nanostructures fabricated by nanosphere lithography using an organometallic etch mask

    NASA Astrophysics Data System (ADS)

    Ling, Xing Yi; Acikgoz, Canet; Phang, In Yee; Hempenius, Mark A.; Reinhoudt, David N.; Vancso, G. Julius; Huskens, Jurriaan

    2010-08-01

    A new approach for fabricating porous structures on silicon substrates and on polymer surfaces, using colloidal particle arrays with a polymer mask of a highly etch-resistant organometallic polymer, is demonstrated. Monolayers of silica particles, with diameters of 60 nm, 150 nm, 300 nm, or 500 nm, were deposited either on a silicon substrate or on a surface coated with polyethersulfone (PES), and the voids of the arrays were filled with poly(ferrocenylmethylphenylsilane) (PFMPS). Argon ion sputtering removed the excess PFMPS on the particles which enabled removal of the particles with HF. Further pattern transfer steps with reactive ion etching for different time intervals provided structures in silicon or in a PES layer. Free-standing PES membranes exhibiting regular arrays of circular holes with high porosity were fabricated by using cellulose acetate as a sacrificial layer. The pores obtained on silicon substrates after etching were used as molds for nanoimprint lithography (NIL). A combination of the techniques of nanosphere lithography (NSL) and NIL has resulted in 3D nanostructures with a hemispherical shape (inherited from the nanoparticles) which was obtained both in silicon and in PMMA.

  2. Development of a methodology to assess organometallic effects on bioenergetic systems

    SciTech Connect

    Packer, L.; Mehlhorn, R.J.

    1981-06-01

    A methodology for assessing the impact of subacute concentrations of organometallic agents on bioenergetic and oxidative damage processes in animals, cells and energy transducing subcellular organelles is being developed. Several of the assays are noninvasive and thus lend themselves to human tests. At the whole-animal level we utilize a treadmill chamber where physiological parameters of exercising animals are monitored. These include parameters of whole animals' work performance such as oxygen consumption, carbon dioxide evolution and endurance. Oxidative damage can be monitored in experiments by analyzing expired air of the animals for ethane and n-pentane. These alkanes correlate with lipid peroxidation in vivo. At the cellular and subcellular levels, respiratory activity, lipid peroxidation and free radical species are assayed. Respiratory activity is measured in muscle homogenates and isolated mitochondria using substrates which feed into different segments of the electron transport chain. To demonstrate how these assay procedures correlate, iron deficiency anemia in rats was analyzed. Physiologically, iron deficiency caused a 90% decrease in endurance which correlated with an 80% decrease in pyruvate-malate oxidation rates in muscle homogenates. Significant but smaller effects were seen in hemoglobin/hematocrit levels (50% decrease) and in maximal oxygen consumption (50% decrease). Tissue free-radical signals observed by ESR at room temperature increased with exercise.

  3. One-Step Liquid-Phase Synthesis of Carbon Nanotubes with Catalyst Precursors of Organometallic Complexes

    NASA Astrophysics Data System (ADS)

    Yamagiwa, Kiyofumi; Kikitsu, Tomoka; Yamashita, Shunsuke; Kuwano, Jun

    2011-01-01

    This paper describes a simple, low cost one-step liquid-phase process for the synthesis of highly aligned carbon nanotube (CNT) arrays (HACNTAs). Highly pure HACNTAs were grown on a stainless steel substrate by resistance-heating in methanol solution containing one of the organometallic complex catalyst precursors, ferrocene Fe(C5H5)2 and iron pentacarbonyl Fe(CO)5. Effects of the catalyst precursors on the formation and morphologies of HACNTAs were examined. A small amount of non-aligned multi-walled CNTs (MWCNTs) were grown from 1 mM Fe(C5H5)2 methanol solution. Highly pure HACNTAs composed of MWCNTs were readily grown from 10 and 40 mM Fe(C5H5)2 methanol solutions by this one-step liquid-phase process. From the Fe(CO)5 methanol solution, HACNTAs were prepared even at a very low Fe(CO)5 concentration of 0.01 mM, which was about 1/1000 lower than that of Fe(C5H5)2. The optimal low concentration is attributed to the low decomposition temperature of Fe(CO)5.

  4. Organometallic Complex Formed by an Unconventional Radical S-Adenosylmethionine Enzyme.

    PubMed

    Dong, Min; Horitani, Masaki; Dzikovski, Boris; Pandelia, Maria-Eirini; Krebs, Carsten; Freed, Jack H; Hoffman, Brian M; Lin, Hening

    2016-08-10

    Pyrococcus horikoshii Dph2 (PhDph2) is an unusual radical S-adenosylmethionine (SAM) enzyme involved in the first step of diphthamide biosynthesis. It catalyzes the reaction by cleaving SAM to generate a 3-amino-3-carboxypropyl (ACP) radical. To probe the reaction mechanism, we synthesized a SAM analogue (SAMCA), in which the ACP group of SAM is replaced with a 3-carboxyallyl group. SAMCA is cleaved by PhDph2, yielding a paramagnetic (S = 1/2) species, which is assigned to a complex formed between the reaction product, α-sulfinyl-3-butenoic acid, and the [4Fe-4S] cluster. Electron-nuclear double resonance (ENDOR) measurements with (13)C and (2)H isotopically labeled SAMCA support a π-complex between the C═C double bond of α-sulfinyl-3-butenoic acid and the unique iron of the [4Fe-4S] cluster. This is the first example of a radical SAM-related [4Fe-4S](+) cluster forming an organometallic complex with an alkene, shedding additional light on the mechanism of PhDph2 and expanding our current notions for the reactivity of [4Fe-4S] clusters in radical SAM enzymes. PMID:27465315

  5. Polybenzimidazole compounds

    DOEpatents

    Klaehn, John R.; Peterson, Eric S.; Wertsching, Alan K.; Orme, Christopher J.; Luther, Thomas A.; Jones, Michael G.

    2010-08-10

    A PBI compound that includes imidazole nitrogens, at least a portion of which are substituted with an organic-inorganic hybrid moiety. At least 85% of the imidazole nitrogens may be substituted. The organic-inorganic hybrid moiety may be an organosilane moiety, for example, (R)Me.sub.2SiCH.sub.2--, where R is selected from among methyl, phenyl, vinyl, and allyl. The PBI compound may exhibit similar thermal properties in comparison to the unsubstituted PBI. The PBI compound may exhibit a solubility in an organic solvent greater than the solubility of the unsubstituted PBI. The PBI compound may be included in separatory media. A substituted PBI synthesis method may include providing a parent PBI in a less than 5 wt % solvent solution. Substituting may occur at about room temperature and/or at about atmospheric pressure. Substituting may use at least five equivalents in relation to the imidazole nitrogens to be substituted or, preferably, about fifteen equivalents.

  6. A convenient method for the computer-aided molecular design of carborane containing compounds.

    PubMed

    Johnsamuel, Jayaseharan; Byun, Youngjoo; Jones, Thomas P; Endo, Yasuyuki; Tjarks, Werner

    2003-10-01

    Computer-aided molecular design (CAMD) of carborane containing compounds is of growing interest for scientists involved in boron neutron capture therapy (BNCT) and other pharmaceutical applications. However, the complex organo-metallic structures of carboranes pose difficulties in modeling and docking of these structures. This is the first report of a new strategy for modeling and docking of carborane containing molecules with the readily available software packages HyperChem, SYBYL and FlexX. It is intended as a guide for boron chemists interested in using CAMD of carborane containing agents for medical applications such as BNCT. PMID:12951095

  7. Coordination Chemistry of [Co(acac)2 ] with N-Doped Graphene: Implications for Oxygen Reduction Reaction Reactivity of Organometallic Co-O4 -N Species.

    PubMed

    Han, Jongwoo; Sa, Young Jin; Shim, Yeonjun; Choi, Min; Park, Noejung; Joo, Sang Hoon; Park, Sungjin

    2015-10-19

    Hybridization of organometallic complexes with graphene-based materials can give rise to enhanced catalytic performance. Understanding the chemical structures within hybrid materials is of primary importance. In this work, archetypical hybrid materials are synthesized by the reaction of an organometallic complex, [Co(II) (acac)2 ] (acac=acetylacetonate), with N-doped graphene-based materials at room temperature. Experimental characterization of the hybrid materials and theoretical calculations reveal that the organometallic cobalt-containing species is coordinated to heterocyclic groups in N-doped graphene as well as to its parental acac ligands. The hybrid material shows high electrocatalytic activity for the oxygen reduction reaction (ORR) in alkaline media, and superior durability and methanol tolerance to a Pt/C catalyst. Based on the chemical structures and ORR experiments, the catalytically active species is identified as a Co-O4 -N structure. PMID:26331625

  8. Coupling the Phase Field Method for diffusive transformations with dislocation density-based crystal plasticity: Application to Ni-based superalloys

    NASA Astrophysics Data System (ADS)

    Cottura, M.; Appolaire, B.; Finel, A.; Le Bouar, Y.

    2016-09-01

    A phase field model is coupled to strain gradient crystal plasticity based on dislocation densities. The resulting model includes anisotropic plasticity and the size-dependence of plastic activity, required when plasticity is confined in region below few microns in size. These two features are important for handling microstructure evolutions during diffusive phase transformations that involve plastic deformation occurring in confined areas such as Ni-based superalloys undergoing rafting. The model also uses a storage-recovery law for the evolution of the dislocation density of each glide system and a hardening matrix to account for the short-range interactions between dislocations. First, it is shown that the unstable modes during the morphological destabilization of a growing misfitting circular precipitate are selected by the anisotropy of plasticity. Then, the rafting of γ‧ precipitates in a Ni-based superalloy is investigated during [100] creep loadings. Our model includes most of the important physical phenomena accounted for during the microstructure evolution, such as the presence of different crystallographic γ‧ variants, their misfit with the γ matrix, the elastic inhomogeneity and anisotropy, the hardening, anisotropy and viscosity of plasticity. In agreement with experiments, the model predicts that rafting proceeds perpendicularly to the tensile loading axis and it is shown that plasticity slows down significantly the evolution of the rafts.

  9. Performance of chromia- and alumina-forming Fe- and Ni-base alloys exposed to metal dusting environments: The effect of water vapor and temperature

    SciTech Connect

    Rouaix-Vande Put, Aurelie; Unocic, Kinga A.; Brady, Michael P.; Pint, Bruce A.

    2015-11-18

    Fe- and Ni-base alloys including an alumina-forming austenitic alloy were exposed for 500 h under metal dusting environments with varying temperature, gas composition and total pressure. For one H2–CO–CO2–H2O environment, the increase in temperature from 550 to 750 °C generally decreased metal dusting. When H2O was added to a H2–CO–CO2 environment at 650 °C, the metal dusting attack was reduced. Even after 5000 h at a total pressure of 9.1 atm with 20%H2O, the higher alloyed specimens retained a thin protective oxide. Lastly, for gas mixtures containing little or no H2O, the Fe-base alloys were less resistant to metal dusting than Ni-base alloys.

  10. Volatile organometallic complexes suitable for use in chemical vapor depositions on metal oxide films

    DOEpatents

    Giolando, Dean M.

    2003-09-30

    Novel ligated compounds of tin, titanium, and zinc are useful as metal oxide CVD precursor compounds without the detriments of extreme reactivity yet maintaining the ability to produce high quality metal oxide coating by contact with heated substrates.

  11. Multipurpose Compound

    NASA Technical Reports Server (NTRS)

    1983-01-01

    Specially formulated derivatives of an unusual basic compound known as Alcide may be the answer to effective treatment and prevention of the disease bovine mastitis, a bacterial inflammation of a cow's mammary gland that results in loss of milk production and in extreme cases, death. Manufactured by Alcide Corporation the Alcide compound has killed all tested bacteria, virus and fungi, shortly after contact, with minimal toxic effects on humans or animals. Alcide Corporation credits the existence of the mastitis treatment/prevention products to assistance provided the company by NERAC, Inc.

  12. Electronic and magnetic properties of silicon supported organometallic molecular wires: a density functional theory (DFT) study

    NASA Astrophysics Data System (ADS)

    Liu, Xia; Tan, Yingzi; Li, Xiuling; Wu, Xiaojun; Pei, Yong

    2015-08-01

    The electronic and magnetic properties of transition metal (TM = Sc, Ti, V, Cr and Mn) atom incorporated single and double one-dimensional (1D) styrene molecular wires confined on the hydrogen-terminated Si(100) surface are explored for the first time by means of spin-polarized density functional theory, denoted as Si-[TM(styrene)]. It is unveiled that TM atoms bind asymmetrically to the adjacent phenyl rings, which leads to novel electronic and magnetic properties in stark contrast to the well-studied gas phase TM-benzene molecular wires. Si-[Mn(styrene)]∞ and Si-[Cr(styrene)]∞ single molecular wires (SMWs) are a ferromagnetic semiconductor and half metal, respectively. Creation of H-atom defects on the silicon surface can introduce an impurity metallic band, which leads to novel half-metallic magnetism of a Si-[Mn(styrene)]∞ system. Moreover, double molecular wires (DMWs) containing two identical or hetero SMWs are theoretically designed. The [Mn(styrene)]∞-[Cr(styrene)]∞ DMW exhibits half-metallic magnetism where the spin-up and spin-down channels are contributed by two single molecular wires. Finally, we demonstrate that introducing a TM-defect may significantly affect the electronic structure and magnetic properties of molecular wires. These studies provide new insights into the structure and properties of surface supported 1-D sandwiched molecular wires and may inspire the future experimental synthesis of substrate confined organometallic sandwiched molecular wires.The electronic and magnetic properties of transition metal (TM = Sc, Ti, V, Cr and Mn) atom incorporated single and double one-dimensional (1D) styrene molecular wires confined on the hydrogen-terminated Si(100) surface are explored for the first time by means of spin-polarized density functional theory, denoted as Si-[TM(styrene)]. It is unveiled that TM atoms bind asymmetrically to the adjacent phenyl rings, which leads to novel electronic and magnetic properties in stark contrast to

  13. Mechanistic Studies at the Interface Between Organometallic Chemistry and Homogeneous Catalysis

    SciTech Connect

    Casey, Charles P

    2012-11-14

    Mechanistic Studies at the Interface Between Organometallic Chemistry and Homogeneous Catalysis Charles P. Casey, Principal Investigator Department of Chemistry, University of Wisconsin - Madison, Madison, Wisconsin 53706 Phone 608-262-0584 FAX: 608-262-7144 Email: casey@chem.wisc.edu http://www.chem.wisc.edu/main/people/faculty/casey.html Executive Summary. Our goal was to learn the intimate mechanistic details of reactions involved in homogeneous catalysis and to use the insight we gain to develop new and improved catalysts. Our work centered on the hydrogenation of polar functional groups such as aldehydes and ketones and on hydroformylation. Specifically, we concentrated on catalysts capable of simultaneously transferring hydride from a metal center and a proton from an acidic oxygen or nitrogen center to an aldehyde or ketone. An economical iron based catalyst was developed and patented. Better understanding of fundamental organometallic reactions and catalytic processes enabled design of energy and material efficient chemical processes. Our work contributed to the development of catalysts for the selective and mild hydrogenation of ketones and aldehydes; this will provide a modern green alternative to reductions by LiAlH4 and NaBH4, which require extensive work-up procedures and produce waste streams. (C5R4OH)Ru(CO)2H Hydrogenation Catalysts. Youval Shvo described a remarkable catalytic system in which the key intermediate (C5R4OH)Ru(CO)2H (1) has an electronically coupled acidic OH unit and a hydridic RuH unit. Our efforts centered on understanding and improving upon this important catalyst for reduction of aldehydes and ketones. Our mechanistic studies established that the reduction of aldehydes by 1 to produce alcohols and a diruthenium bridging hydride species occurs much more rapidly than regeneration of the ruthenium hydride from the diruthenium bridging hydride species. Our mechanistic studies require simultaneous transfer of hydride from ruthenium to

  14. Metal-carbonyl organometallic polymers, PFpP, as resists for high-resolution positive and negative electron beam lithography.

    PubMed

    Zhang, J; Cao, K; Wang, X S; Cui, B

    2015-12-25

    Metal-containing resists for electron beam lithography (EBL) are attracting attention owing to their high dry etching resistance and possibility for directly patterning metal-containing nanostructures. The newly developed organometallic metal carbonyl polymers, PFpP, can function as EBL resists with strong etching resistance. One significant feature of the PFpP resist is its high resolution. Line arrays with line-widths as narrow as 17 nm have been created. The resist can also be used in positive tone. PMID:26481609

  15. Organometallic molecular wires as versatile modules for energy-level alignment of the metal-molecule-metal junction.

    PubMed

    Sugimoto, Kaho; Tanaka, Yuya; Fujii, Shintaro; Tada, Tomofumi; Kiguchi, Manabu; Akita, Munetaka

    2016-04-30

    The organometallic Ru molecular wires 1-3 Ru(PR3)4(C[triple bond, length as m-dash]CC5H5N)2 [(PR3)4 = (dppe)2 (1), [P(OMe3)]4 (2), and (dmpe)2 (3)] show significantly higher conductance compared to their organic counterpart, 1,4-dipyridyl butadiyne (4). CV and UV-Vis measurements and DFT calculations suggest that the high-lying HOMOs of the Ru wires are the key factor for the high conductance. PMID:26996138

  16. Optical control of growth of AlxGa1 - xAs by organometallic molecular beam epitaxy

    NASA Astrophysics Data System (ADS)

    Aspnes, D. E.; Quinn, W. E.; Gregory, S.

    1990-12-01

    Using spectroellipsometry, we obtain information on the near-surface composition x of epitaxial AlxGa1-xAs layers during crystal growth by organometallic molecular beam epitaxy and use this information to regulate the flow of triethylaluminum to the growth surface. The resulting closed-loop control system maintains the imaginary part of the dielectric response of thick AlxGa1-xAs films constant to an equivalent compositional precision better than ±0.001 over extended periods of time.

  17. Organometallic chemical vapor deposition of silicon nitride films enhanced by atomic nitrogen generated from surface-wave plasma

    SciTech Connect

    Okada, H.; Kato, M.; Ishimaru, T.; Sekiguchi, H.; Wakahara, A.; Furukawa, M.

    2014-02-20

    Organometallic chemical vapor deposition of silicon nitride films enhanced by atomic nitrogen generated from surface-wave plasma is investigated. Feasibility of precursors of triethylsilane (TES) and bis(dimethylamino)dimethylsilane (BDMADMS) is discussed based on a calculation of bond energies by computer simulation. Refractive indices of 1.81 and 1.71 are obtained for deposited films with TES and BDMADMS, respectively. X-ray photoelectron spectroscopy (XPS) analysis of the deposited film revealed that TES-based film coincides with the stoichiometric thermal silicon nitride.

  18. Nitrogen adduction by three coordinate group 10 organometallic cations: platinum is favoured over nickel and palladium.

    PubMed

    Woolley, Matthew J; Khairallah, George N; Donnelly, Paul S; O'Hair, Richard A J

    2011-07-30

    Previous studies have shown that highly reactive product ions formed by collision-induced dissociation (CID) of precursor ions generated via electrospray can readily react with residual solvent or drying gases, especially in ion trap mass spectrometers. Here we report on the rapid addition of nitrogen to the coordinatively unsaturated organoplatinum cation, [(phen)Pt(CH(3))](+) (phen=1,10-phenanthroline) formed via decarboxylation of the acetate complex [(phen)Pt(O(2) CCH(3))](+). This contrasts with the related coordinatively unsaturated group 10 cations: addition of nitrogen to [(phen)Pd(CH(3))](+) occurs at longer reaction times, whereas addition of nitrogen to [(phen)Ni(CH(3))](+) is virtually non-existent. To better understand these reactions, density functional theory (DFT) calculations were carried out at the B3LYP/SDD6-31+G(d) level of theory to determine the N(2)-binding energies of [(phen)M(CH(3))](+). [(phen)Pt(CH(3))](+) has a higher binding energy to N(2) (1.06 eV) than either [(phen)Ni(CH(3))](+) (0.61 eV) or [(phen)Pd(CH(3))](+) (0.66 eV), consistent with the experimental ease of addition of nitrogen to the coordinatively unsaturated organometallic complexes, [(phen)M(CH(3))](+). Finally, [(phen)M(CH(3))](+) are reactive to other background gases, forming [(phen)M(O(2))](.+) (for M=Ni) in reactions with oxygen and undergoing water addition (for M=Ni, Pd and Pt) and water addition/CH(4) elimination reactions to yield [(phen)M(OH)](+) (for M=Ni and Pt). PMID:21698691

  19. Dual-targeting organometallic ruthenium(II) anticancer complexes bearing EGFR-inhibiting 4-anilinoquinazoline ligands.

    PubMed

    Zhang, Yang; Zheng, Wei; Luo, Qun; Zhao, Yao; Zhang, Erlong; Liu, Suyan; Wang, Fuyi

    2015-08-01

    We have recently demonstrated that complexation with (η(6)-arene)Ru(II) fragments confers 4-anilinoquinazoline pharmacophores a higher potential for inducing cellular apoptosis while preserving the highly inhibitory activity of 4-anilinoquinazolines against EGFR and the reactivity of the ruthenium centre to 9-ethylguanine (Chem. Commun., 2013, 49, 10224-10226). Reported herein are the synthesis, characterisation and evaluation of the biological activity of a new series of ruthenium(ii) complexes of the type [(η(6)-arene)Ru(N,N-L)Cl]PF6 (arene = p-cymene, benzene, 2-phenylethanol or indane, L = 4-anilinoquinazolines). These organometallic ruthenium complexes undergo fast hydrolysis in aqueous solution. Intriguingly, the ligation of (arene)Ru(II) fragments with 4-anilinoquinazolines not only makes the target complexes excellent EGFR inhibitors, but also confers the complexes high affinity to bind to DNA minor grooves while maintaining their reactivity towards DNA bases, characterising them with dual-targeting properties. Molecular modelling studies reveal that the hydrolysis of these complexes is a favourable process which increases the affinity of the target complexes to bind to EGFR and DNA. In vitro biological activity assays show that most of this group of ruthenium complexes are selectively active inhibiting the EGF-stimulated growth of the HeLa cervical cancer cell line, and the most active complex [(η(6)-arene)Ru(N,N-L13)Cl]PF6 (, IC50 = 1.36 μM, = 4-(3'-chloro-4'-fluoroanilino)-6-(2-(2-aminoethyl)aminoethoxy)-7-methoxyquinazoline) is 29-fold more active than its analogue, [(η(6)-arene)Ru(N,N-ethylenediamine)Cl]PF6, and 21-fold more active than gefitinib, a well-known EGFR inhibitor in use clinically. These results highlight the strong promise to develop highly active ruthenium anticancer complexes by ligation of cytotoxic ruthenium pharmacophores with bioactive organic molecules. PMID:26106875

  20. High-conductive organometallic molecular wires with delocalized electron systems strongly coupled to metal electrodes.

    PubMed

    Schwarz, Florian; Kastlunger, Georg; Lissel, Franziska; Riel, Heike; Venkatesan, Koushik; Berke, Heinz; Stadler, Robert; Lörtscher, Emanuel

    2014-10-01

    Besides active, functional molecular building blocks such as diodes or switches, passive components, for example, molecular wires, are required to realize molecular-scale electronics. Incorporating metal centers in the molecular backbone enables the molecular energy levels to be tuned in respect to the Fermi energy of the electrodes. Furthermore, by using more than one metal center and sp-bridging ligands, a strongly delocalized electron system is formed between these metallic "dopants", facilitating transport along the molecular backbone. Here, we study the influence of molecule-metal coupling on charge transport of dinuclear X(PP)2FeC4Fe(PP)2X molecular wires (PP = Et2PCH2CH2PEt2); X = CN (1), NCS (2), NCSe (3), C4SnMe3 (4), and C2SnMe3 (5) under ultrahigh vacuum and variable temperature conditions. In contrast to 1, which showed unstable junctions at very low conductance (8.1 × 10(-7) G0), 4 formed a Au-C4FeC4FeC4-Au junction 4' after SnMe3 extrusion, which revealed a conductance of 8.9 × 10(-3) G0, 3 orders of magnitude higher than for 2 (7.9 × 10(-6) G0) and 2 orders of magnitude higher than for 3 (3.8 × 10(-4) G0). Density functional theory (DFT) confirmed the experimental trend in the conductance for the various anchoring motifs. The strong hybridization of molecular and metal states found in the C-Au coupling case enables the delocalized electronic system of the organometallic Fe2 backbone to be extended over the molecule-metal interfaces to the metal electrodes to establish high-conductive molecular wires. PMID:25233125

  1. Redox Chemistry in Thin Layers of Organometallic Complexes Prepared Using Ion Soft Landing

    SciTech Connect

    Peng, Wen-Ping; Johnson, Grant E.; Fortmeyer, Ivy C.; Wang, Peng; Hadjar, Omar; Cooks, Robert G.; Laskin, Julia

    2011-01-01

    Soft landing (SL) of mass-selected ions is used to introduce catalytically-active metal complexes complete with organic ligands into the gas phase and then to transfer them as ions onto an inert surface. This is part of an effort to prepare materials with defined active sites and thus achieve molecular design of surfaces in a highly controlled way. Solution-phase electrochemical studies have shown that VIVO(salen) reacts in the presence of acid to form VVO(salen)+ and the deoxygenated VIII(salen)+ complex -- a key intermediate in the four electron reduction of O2 by vanadium-salen. In this work, the VVO(salen)+ and [NiII(salen)+H]+ complexes were generated by electrospray ionization and mass-selected before being deposited into an inert fluorinated self-assembled monolayer (FSAM) surface on gold. A time dependence study after ion deposition showed loss of O from VVO(salen)+ forming VIII(salen)+ over a four-day period, indicating a slow interfacial reduction process. Similar results were obtained when other protonated molecules were co-deposited with VVO(salen)+ on the FSAM surface. In all these experiments oxidation of the VIII(salen)+ product occurred upon exposure to oxygen or to air. The cyclic regeneration of VVO(salen)+ upon exposure to molecular oxygen and its subsequent reduction to VIII(salen)+ in vacuum completes the catalytic cycle of O2 reduction by the immobilized vanadium-salen species. Moreover, our results represent the first evidence of formation of reactive organometallic complexes on substrates in the absence of solvent. Remarkably, deoxygenation of the oxo-vanadium complex, previously observed only in highly acidic non-aqueous solvents, occurs on the surface in the UHV environment using an acid which is deposited into the inert monolayer. This acid can be a protonated metal complex, e.g. [NiII(salen)+H]+ or an organic acid such as protonated diaminododecane.

  2. Probing the chemistry, electronic structure and redox energetics in pentavalent organometallic actinide complexes

    SciTech Connect

    Graves, Christopher R; Vaughn, Anthony E; Morris, David E; Kiplinger, Jaqueline L

    2008-01-01

    Complexes of the early actinides (Th-Pu) have gained considerable prominence in organometallic chemistry as they have been shown to undergo chemistries not observed with their transition- or lanthanide metal counterparts. Further, while bonding in f-element complexes has historically been considered to be ionic, the issue of covalence remains a subject of debate in the area of actinide science, and studies aimed at elucidating key bonding interactions with 5f-orbitals continue to garner attention. Towards this end, our interests have focused on the role that metal oxidation state plays in the structure, reactivity and spectral properties of organouranium complexes. We report our progress in the synthesis of substituted U{sup V}-imido complexes using various routes: (1) Direct oxidation of U{sup IV}-imido complexes with copper(I) salts; (2) Salt metathesis with U{sup V}-imido halides; (3) Protonolysis and insertion of an U{sup V}-imido alkyl or aryl complex with H-N{double_bond}CPh{sub 2} or N{triple_bond}C-Ph, respectively, to form a U{sup V}-imido ketimide complex. Further, we report and compare the crystallographic, electrochemical, spectroscopic and magnetic characterization of the pentavalent uranium (C{sub 5}Me{sub 5}){sub 2}U({double_bond}N-Ar)(Y) series (Y = OTf, SPh, C{triple_bond}C-Ph, NPh{sub 2}, OPh, N{double_bond}CPh{sub 2}) to further interrogate the molecular, electronic, and magnetic structures of this new class of uranium complexes.

  3. Catalytic ionic hydrogenation of ketones using tungsten or molybdenum organometallic species

    DOEpatents

    Voges, Mark; Bullock, R. Morris

    2000-01-01

    The present invention is a process for the catalytic hydrogenation of ketones and aldehydes to alcohols at low temperatures and pressures using organometallic molybdenum and tungsten complexes. The functional group is selected from groups represented by the formulas R(C.dbd.O)R' and R(C.dbd.O)H, wherein R and R' are selected from hydrogen or any alkyl or aryl group. The active catalyst for the process has the form: [CpM(CO).sub.2 (PR*.sub.3) L].sup.+ A.sup.-, where Cp=.eta..sup.5 -R.sup..tangle-solidup..sub.m C.sub.5 H.sub.5-m and R.sup..tangle-solidup. represents an alkyl group or a halogen (F, Cl, Br, I) or R.sup..tangle-solidup. =OR' (where R'=H, an alkyl group or an aryl group) or R.sup..tangle-solidup. =CO.sub.2 R' (where R'=H, an alkyl group or an aryl group) and m=0 to 5; M represents a molybdenum atom or a tungsten atom; R*.sub.3 represents three hydrocarbon groups selected from a cyclohexyl group (C.sub.6 H.sub.11), a methyl group (CH.sub.3), and a phenyl group (C.sub.6 H.sub.5) and all three R* groups can be the same or different or two of the three groups can be the same; L represents a ligand; and A.sup.- represents an anion. In another embodiment, one, two or three of the R* groups can be an OR*.

  4. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2001-01-01

    Seawater and natural brines accounted for about 63% of US magnesium compounds production during 2000. Premier Services in Florida, Dow Chemical in Michigan, Martin Marietta Magnesia Specialties, and Rohm & Haas recovered dead-burned and caustic-calcined magnesias from seawater. And Premier Services' recoveries, in Nevada, were from magnasite.

  5. Laser photochemistry of gallium-containing compounds. [Trimethylgallium

    SciTech Connect

    Baughcum, S.L.; Oldenborg, R.C.

    1986-01-01

    The production of gas-phase gallium atoms in the photolysis of trimethylgallium has been investigated at 193 nm and at other laser wavelengths. Ground state (4 /sup 2/P/sup 0//sub 1/2) and metastable (4 /sup 2/P/sup 0//sub 3/2/) gallium atoms are detected using laser-induced fluorescence techniques. Our results indicate that gallium atoms continue to be produced at long times after the laser pulse. The observed dependence on photolysis laser fluence, trimethylgallium pressure, and buffer gas pressure are consistent with a mechanism in which highly excited gallium methyl radicals undergo unimolecular decomposition to produce gallium atoms. Since this process is observed to happen on the time scale of hundreds of microseconds, these results have important implications for studies of metal deposition and direct laser writing by laser photolysis of organometallic compounds. 31 refs., 5 figs.

  6. Investigation of the Hydrolysis of Perovskite Organometallic Halide CH3NH3PbI3 in Humidity Environment

    PubMed Central

    Zhao, Jiangtao; Cai, Bing; Luo, Zhenlin; Dong, Yongqi; Zhang, Yi; Xu, Han; Hong, Bin; Yang, Yuanjun; Li, Liangbin; Zhang, Wenhua; Gao, Chen

    2016-01-01

    Instability of emerging perovskite organometallic halide in humidity environment is the biggest obstacle for its potential applications in solar energy harvest and electroluminescent display. Understanding the detailed decay mechanism of these materials in moisture is a critical step towards the final appropriate solutions. As a model study presented in this work, in situ synchrotron radiation x-ray diffraction was combined with microscopy and gravimetric analysis to study the degradation process of CH3NH3PbI3 in moisture, and the results reveal that: 1) intermediate monohydrated CH3NH3PbI3·H2O is detected in the degradation process of CH3NH3PbI3 and the final decomposition products are PbI2 and aqueous CH3NH3I; 2) the aqueous CH3NH3I could hardly further decompose into volatile CH3NH2, HI or I2; 3) the moisture disintegrate CH3NH3PbI3 and then alter the distribution of the decomposition products, which leads to an incompletely-reversible reaction of CH3NH3PbI3 hydrolysis and degrades the photoelectric properties. These findings further elucidate the picture of hydrolysis process of perovskite organometallic halide in humidity environment. PMID:26924112

  7. Back-extraction of trace elements from organometallic-halide extracts for determination by flameless atomic absorption spectrometry

    USGS Publications Warehouse

    Clark, J.R.; Viets, J.G.

    1981-01-01

    The Methyl isobutyl ketone-Amine synerGistic Iodkte Complex (MAGIC) extraction system offers the advantage that a large number of trace elements can be rapidly determined with a single sample preparation procedure. However, many of the elements extracted by the MAGIC system form volatile organometallic halide salts when the organic extract is heated in the graphite furnace. High concentrations of some elements such as Cu and Zn extracted by the system from anomalous geological samples produce serious interferences when certain other elements are determined by flameless atomic absorption. Stripping systems have been developed using solutions of HNO3, H2SO4, and CH3COOH individually or combined with H2O2 in order to circumvent these problems. With these systems most of the elements in the organic extract can be sequentially stripped into an aqueous phase. Organometallic volatilization and the most serious interelement interferences, therefore, can be eliminated by stripping with various combinations of reagents in a series of steps.

  8. Black-extraction of trace elements from organometallic-halide extracts for determination by flameless atomic absorption spectrometry

    SciTech Connect

    Clark, J.R.; Viets, J.G.

    1981-01-01

    The Methyl isobutyl ketone-Amine synerGistic Iodide Complex (MAGIC) extraction system offers the advantage that a large number of trace elements can be rapidly determined with a single sample preparation procedure. However, many of the elements extracted by the MAGIC system form volatile organometallic halide salts when the organic extract is heated in the graphite furnace. High concentrations of some elements such as Cu and Zn extracted by the system from anomalous geological samples produce serious interferences when certain other elements are determined by flameless atomic absorption. Stripping systems have been developed using solutions of HNO/sub 3/, H/sub 2/SO/sub 4/, and CH/sub 3/COOH individually or combined with H/sub 2/O/sub 2/ in order to circumvent these problems. With these systems most of the elements in the organic extract can be sequentially stripped into an aqueous phase. Organometallic volatilization and the most serious interelement interferences, therefore, can be eliminated by stripping with various combinations of reagents in a series of steps.

  9. Optical properties of organometallic perovskite: An ab initio study using relativistic GW correction and Bethe-Salpeter equation

    NASA Astrophysics Data System (ADS)

    Ahmed, Towfiq; La-o-vorakiat, C.; Salim, T.; Lam, Y. M.; Chia, Elbert E. M.; Zhu, Jian-Xin

    2014-12-01

    In the development of highly efficient photovoltaic cells, solid perovskite systems have demonstrated unprecedented promise, with the figure of merit exceeding nineteen percent of efficiency. In this paper, we investigate the optical and vibrational properties of organometallic cubic perovskite CH3NH3PbI3 using first-principles calculations. For accurate theoretical description, we go beyond conventional density functional theory (DFT), and calculate optical conductivity using relativistic quasi-particle (GW) correction. Incorporating these many-body effects, we further solve Bethe-Salpeter equations (BSE) for excitons, and found enhanced optical conductivity near the gap edge. Due to the presence of organic methylammonium cations near the center of the perovskite cell, the system is sensitive to low-energy vibrational modes. We estimate the phonon modes of CH3NH3PbI3 using a small displacement approach, and further calculate the infrared (IR) absorption spectra. Qualitatively, our calculations of low-energy phonon frequencies are in good agreement with our terahertz measurements. Therefore, for both energy scales (around 1.5 eV and 0-20 meV), our calculations reveal the importance of many-body effects and their contributions to the desirable optical properties in the cubic organometallic perovskites system.

  10. Investigation of the Hydrolysis of Perovskite Organometallic Halide CH3NH3PbI3 in Humidity Environment

    NASA Astrophysics Data System (ADS)

    Zhao, Jiangtao; Cai, Bing; Luo, Zhenlin; Dong, Yongqi; Zhang, Yi; Xu, Han; Hong, Bin; Yang, Yuanjun; Li, Liangbin; Zhang, Wenhua; Gao, Chen

    2016-02-01

    Instability of emerging perovskite organometallic halide in humidity environment is the biggest obstacle for its potential applications in solar energy harvest and electroluminescent display. Understanding the detailed decay mechanism of these materials in moisture is a critical step towards the final appropriate solutions. As a model study presented in this work, in situ synchrotron radiation x-ray diffraction was combined with microscopy and gravimetric analysis to study the degradation process of CH3NH3PbI3 in moisture, and the results reveal that: 1) intermediate monohydrated CH3NH3PbI3·H2O is detected in the degradation process of CH3NH3PbI3 and the final decomposition products are PbI2 and aqueous CH3NH3I; 2) the aqueous CH3NH3I could hardly further decompose into volatile CH3NH2, HI or I2; 3) the moisture disintegrate CH3NH3PbI3 and then alter the distribution of the decomposition products, which leads to an incompletely-reversible reaction of CH3NH3PbI3 hydrolysis and degrades the photoelectric properties. These findings further elucidate the picture of hydrolysis process of perovskite organometallic halide in humidity environment.

  11. Investigation of the Hydrolysis of Perovskite Organometallic Halide CH3NH3PbI3 in Humidity Environment.

    PubMed

    Zhao, Jiangtao; Cai, Bing; Luo, Zhenlin; Dong, Yongqi; Zhang, Yi; Xu, Han; Hong, Bin; Yang, Yuanjun; Li, Liangbin; Zhang, Wenhua; Gao, Chen

    2016-01-01

    Instability of emerging perovskite organometallic halide in humidity environment is the biggest obstacle for its potential applications in solar energy harvest and electroluminescent display. Understanding the detailed decay mechanism of these materials in moisture is a critical step towards the final appropriate solutions. As a model study presented in this work, in situ synchrotron radiation x-ray diffraction was combined with microscopy and gravimetric analysis to study the degradation process of CH3NH3PbI3 in moisture, and the results reveal that: 1) intermediate monohydrated CH3NH3PbI3·H2O is detected in the degradation process of CH3NH3PbI3 and the final decomposition products are PbI2 and aqueous CH3NH3I; 2) the aqueous CH3NH3I could hardly further decompose into volatile CH3NH2, HI or I2; 3) the moisture disintegrate CH3NH3PbI3 and then alter the distribution of the decomposition products, which leads to an incompletely-reversible reaction of CH3NH3PbI3 hydrolysis and degrades the photoelectric properties. These findings further elucidate the picture of hydrolysis process of perovskite organometallic halide in humidity environment. PMID:26924112

  12. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2003-01-01

    Seawater and natural brines accounted for about 60 percent of U.S. magnesium compounds production during 2002. Dead-burned and caustic-calcined magnesias were recovered from seawater by Premier Chemicals in Florida. They were also recovered from well brines in Michigan by Dow Chemical, Martin Marietta Magnesia Specialties and Rohm & Haas. And they were recovered from magnesite in Nevada by Premier Chemicals.

  13. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2006-01-01

    In 2005, seawater and natural brines accounted for 51% of US magnesium compounds production. World magnesia production was estimated to be 14.5 Mt. Most of the production came from China, North Korea, Russia and Turkey. Although no specific production figures are available, Japan and the United States are estimated to account for almost one-half of the world's capacity from seawater and brines.

  14. Study on the anti-wear performance of Ni-base composite coating sucker joint that contains nano-diamond and nano-polytetrafluoroethylene.

    PubMed

    Wang, Wei-Zhang; Yan, Xiang-Zhen; Wang, Hai-Wen; Wang, Ming-Bo

    2009-02-01

    With the development of oilfields, the problem of eccentric wear between casing and sucker rod in rod-pumped wells operation is more and more severe. Investigations on the eccentric wear show that the abrasion of sucker rod joint is more serious than the sucker rod itself. A new method of producing the Ni-base composite coating that contains nano-diamond and nano-polytetrafluoroethylene (PTFE) on sucker joint obtained by electrodeposition is presented in this paper. The test results show that the anti-wear performance and hardness of the sucker rod improve significantly with the increase of nano-diamond. The addition of nano-PTFE particle is useful in reducing the friction factor. Field tests demonstrate that the life of the sucker rod joint is increased and the maintenance cycle of the rod-pumped well is prolonged. PMID:19441509

  15. Large-size ultrahigh strength Ni-based bulk metallic glassy matrix composites with enhanced ductility fabricated by spark plasma sintering

    SciTech Connect

    Xie Guoqiang; Louzguine-Luzgin, Dmitri V.; Kimura, Hisamichi; Inoue, Akihisa; Wakai, Fumihiro

    2008-03-24

    Ni-based bulk glassy alloy composites (GACs) simultaneously with ultrahigh strength and enhanced ductility and satisfying large-size requirements were fabricated by spark plasma sintering of gas-atomized Ni{sub 52.5}Nb{sub 10}Zr{sub 15}Ti{sub 15}Pt{sub 7.5} glassy alloy powder blend with ceramic or metal powders. No crystallization of metallic glassy matrix and good bonding state between the particles are responsible for good mechanical properties of the fabricated bulk GACs. The improvement of plastic ductility of the fabricated bulk GACs originates from the structural inhomogeneity caused by the particles inclusion. The additional particulates act as a resisting media causing deviation, branching, and multiplication of shear bands.

  16. Large-size ultrahigh strength Ni-based bulk metallic glassy matrix composites with enhanced ductility fabricated by spark plasma sintering

    NASA Astrophysics Data System (ADS)

    Xie, Guoqiang; Louzguine-Luzgin, Dmitri V.; Kimura, Hisamichi; Inoue, Akihisa; Wakai, Fumihiro

    2008-03-01

    Ni-based bulk glassy alloy composites (GACs) simultaneously with ultrahigh strength and enhanced ductility and satisfying large-size requirements were fabricated by spark plasma sintering of gas-atomized Ni52.5Nb10Zr15Ti15Pt7.5 glassy alloy powder blend with ceramic or metal powders. No crystallization of metallic glassy matrix and good bonding state between the particles are responsible for good mechanical properties of the fabricated bulk GACs. The improvement of plastic ductility of the fabricated bulk GACs originates from the structural inhomogeneity caused by the particles inclusion. The additional particulates act as a resisting media causing deviation, branching, and multiplication of shear bands.

  17. The Effect of Long-Term Thermal Exposure on the Microstructure and Stress Rupture Property of a Directionally Solidified Ni-Based Superalloy

    NASA Astrophysics Data System (ADS)

    Jiang, X. W.; Wang, D.; Xie, G.; Li, H.; Lou, L. H.; Zhang, J.

    2014-09-01

    Microstructural degradation and microstructure-property relationship during long-term thermal exposure in a directionally solidified Ni-based superalloy are systematically studied. The coarsening kinetics of γ' precipitation conforms well to the LSW model during the long-term thermal exposure. The detailed time dependence of MC decomposition during the long-term thermal exposure is revealed. Grain boundary coarsening was mainly facilitated by γ' and M23C6 precipitates coarsening in GBs region, and the GB coarsening kinetics conforms well to the JMAK theory. During different stages of the thermal exposure, dominant factors for the decrease of stress-rupture lifetime vary due to the evolution of multiple microstructures (γ' coarsening, MC decomposition, and grain boundary coarsening).

  18. The Effect of Long-Term Thermal Exposure on the Microstructure and Stress Rupture Property of a Directionally Solidified Ni-Based Superalloy

    NASA Astrophysics Data System (ADS)

    Jiang, X. W.; Wang, D.; Xie, G.; Li, H.; Lou, L. H.; Zhang, J.

    2014-12-01

    Microstructural degradation and microstructure-property relationship during long-term thermal exposure in a directionally solidified Ni-based superalloy are systematically studied. The coarsening kinetics of γ' precipitation conforms well to the LSW model during the long-term thermal exposure. The detailed time dependence of MC decomposition during the long-term thermal exposure is revealed. Grain boundary coarsening was mainly facilitated by γ' and M23C6 precipitates coarsening in GBs region, and the GB coarsening kinetics conforms well to the JMAK theory. During different stages of the thermal exposure, dominant factors for the decrease of stress-rupture lifetime vary due to the evolution of multiple microstructures ( γ' coarsening, MC decomposition, and grain boundary coarsening).

  19. Directional and single-crystal solidification of Ni-base superalloys: Part I. The role of curved isotherms on grain selection

    NASA Astrophysics Data System (ADS)

    D'Souza, N.; Ardakani, M. G.; McLean, M.; Shollock, B. A.

    2000-11-01

    The development of crystallographic texture during directional solidification has been quantitatively analyzed in columnar castings of the Ni-base superalloys, CMSX4 and CM186LC, produced with a range of cooling rates and liquidus front curvatures. It is proposed that the more diffuse crystallographic texture developed in CMSX4 relative to CM186LC results from a combination of the differing local orientation stability condition and the alloys’ solidification characteristics. The implications of these additional factors on the evolution of the axial grain texture, the grain orientations produced in singlecrystal processing, and the stability of spurious grains in processing CMSX4 are discussed. An experimental method is presented to quantitatively analyze the grain selection process in the case of curved liquidus isotherms by retaining the stereology of the primary <001> dendrite growth direction and the local thermal gradient vector. This can account for the stability of spuriously nucleated edge grains in a single-crystal matrix.

  20. Correction: NanoSIMS analysis of an isotopically labelled organometallic ruthenium(II) drug to probe its distribution and state in vitro.

    PubMed

    Lee, Ronald F S; Escrig, Stéphane; Croisier, Marie; Clerc-Rosset, Stéphanie; Knott, Graham W; Meibom, Anders; Davey, Curt A; Johnsson, Kai; Dyson, Paul J

    2015-11-28

    Correction for 'NanoSIMS analysis of an isotopically labelled organometallic ruthenium(II) drug to probe its distribution and state in vitro' by Ronald F. S. Lee et al., Chem. Commun., 2015, DOI: 10.1039/c5cc06983a. PMID:26507472

  1. Synthesis and Migratory-Insertion Reactivity of CpMo(CO)[subscript3](CH[subscript3]): Small-Scale Organometallic Preparations Utilizing Modern Glovebox Techniques

    ERIC Educational Resources Information Center

    Whited, Matthew T.; Hofmeister, Gretchen E.

    2014-01-01

    Experiments are described for the reliable small-scale glovebox preparation of CpMo(CO)[subscript 3](CH[subscript 3]) and acetyl derivatives thereof through phosphine-induced migratory insertion. The robust syntheses introduce students to a variety of organometallic reaction mechanisms and glovebox techniques, and they are easily carried out…

  2. Synthesis and Catalytic Activity of Ruthenium-Indenylidene Complexes for Olefin Metathesis: Microscale Experiments for the Undergraduate Inorganic or Organometallic Laboratories

    ERIC Educational Resources Information Center

    Pappenfus, Ted M.; Hermanson, David L.; Ekerholm, Daniel P.; Lilliquist, Stacie L.; Mekoli, Megan L.

    2007-01-01

    A series of experiments for undergraduate laboratory courses (e.g., inorganic, organometallic or advanced organic) have been developed. These experiments focus on understanding the design and catalytic activity of ruthenium-indenylidene complexes for olefin metathesis. Included in the experiments are the syntheses of two ruthenium-indenylidene…

  3. The design of a bipodal bis(pentafluorophenoxy)aluminate supported on silica as an activator for ethylene polymerization using surface organometallic chemistry.

    PubMed

    Sauter, Dominique W; Popoff, Nicolas; Bashir, Muhammad Ahsan; Szeto, Kai C; Gauvin, Régis M; Delevoye, Laurent; Taoufik, Mostafa; Boisson, Christophe

    2016-04-01

    A new class of well-defined activating supports for olefin polymerization was obtained via the surface organometallic chemistry approach. High activities in slurry polymerization of ethylene along with industrial-grade physical properties of the resulting polyethylene were obtained when these activators were combined with metallocene complexes in the presence of triisobutylaluminium. PMID:26899986

  4. A neutral branched platinum-acetylide complex possessing a tetraphenylethylene core: preparation of a luminescent organometallic gelator and its unexpected spectroscopic behaviour during sol-to-gel transition.

    PubMed

    Ren, Yuan-Yuan; Wu, Nai-Wei; Huang, Junhai; Xu, Zheng; Sun, Dan-Dan; Wang, Cui-Hong; Xu, Lin

    2015-10-21

    A neutral branched platinum-acetylide complex TPA possessing a tetraphenylethylene core was successfully prepared, which was found to form luminescent organometallic gels in ethyl acetate. Stimulated by temperature or F(-), the reversible gel-sol transition was realized. More interestingly, TPA exhibited an unexpected blue shift of the emission during the sol-to-gel transition. PMID:26323961

  5. Grubbs's Cross Metathesis of Eugenol with cis-2-butene-1, 4-diol to Make a Natural Product: An Organometallic Experiment for the Undergraduate Lab

    ERIC Educational Resources Information Center

    Taber, Douglass F.; Frankowski, Kevin J.

    2006-01-01

    A modified experimental procedure for the one-step synthesis that is suitable for the undergraduate organic lab is presented. In the course of work towards the more routine use of air-sensitive organometallic complexes such as the Grubb's catalyst, the natural product (E)-4-(4-hydroxy-3-methoxyphenyl) but-2-en-ol, 4, was synthesized.

  6. Syntheses and characterization of dichlorozirconium porphyrin complexes and their novel organometallic derivatives. X-ray structure of Zr(TPP)Cl[sub 2](THF)

    SciTech Connect

    Heejoon Kim; Dongmok Whang; Kimoon Kim ); Youngkyu Do )

    1993-02-03

    The chemistry of early transition metal porphyrin complexes, especially, that of the second- and third-row metal complexes has not been developed much due in part to their high oxophilicity. The authors have been interested in exploring zirconium and hafnium porphyrin complexes because they may show a rich organometallic chemistry as zirconocene derivatives do. The key entry to the organometallic zirconium porphyrin complexes would be Zr(porphyrin)Cl[sub 2], analogous to ZrCp[sub 2]Cl[sub 2]. The dichloride complex may be converted to organometallic [sigma]-complexes such as dialkyl complexes by the reactions with alkyllithium or Grignard reagents. It may also form organometallic [tau]-complexes by replacing the two chlorides with a cyclooctatetraenyl dianion or a dicarbollide dianion. Indeed, the authors have succeeded in preparing Zr(por)Cl[sub 2] (por = OEP, TPP) and their organometallic derivatives Zr(TPP)Me[sub 2] and Zr(OEP)([eta][sup 5]-C[sub 2]B[sub 9]H[sub 11]). They have presented the preliminary results on their syntheses and characterization by spectroscopy but have been unable to grow X-ray-quality crystals of either of the organometallic complexes until recently. When they finished the structural characterization of Zr(OEP)([eta][sup 5]C[sub 2]B[sub 9]H[sub 11]) by X-ray crystallography, however, Arnold and co-workers published the synthesis and characterization of Zr(OEP)Cl[sub 2] and several organometallic complexes derived from it, including Zr(OEP)(CH[sub 2]SiMe[sub 3])[sub 2] and Zr(OEP)([eta][sup 5]-C[sub 2]B[sub 9]H[sub 11]). Here they present their results on the syntheses and characterization of Zr(por)Cl[sub 2] (por = OEP, TPP), Zr(TPP)Me[sub 2], and Zr(OEP)([eta][sup 5]-C[sub 2]B[sub 9]H[sub 11]) and the X-ray structure of Zr(TPP)Cl[sub 2](THF). 22 refs., 2 tabs.

  7. Organometallic photovoltaics: a new and versatile approach for harvesting solar energy using conjugated polymetallaynes.

    PubMed

    Wong, Wai-Yeung; Ho, Cheuk-Lam

    2010-09-21

    Energy remains one of the world's great challenges. Growing concerns about limited fossil fuel resources and the accumulation of CO(2) in the atmosphere from burning those fuels have stimulated tremendous academic and industrial interest. Researchers are focusing both on developing inexpensive renewable energy resources and on improving the technologies for energy conversion. Solar energy has the capacity to meet increasing global energy needs. Harvesting energy directly from sunlight using photovoltaic technology significantly reduces atmospheric emissions, avoiding the detrimental effects of these gases on the environment. Currently inorganic semiconductors dominate the solar cell production market, but these materials require high technology production and expensive materials, making electricity produced in this manner too costly to compete with conventional sources of electricity. Researchers have successfully fabricated efficient organic-based polymer solar cells (PSCs) as a lower cost alternative. Recently, metalated conjugated polymers have shown exceptional promise as donor materials in bulk-heterojunction solar cells and are emerging as viable alternatives to the all-organic congeners currently in use. Among these metalated conjugated polymers, soluble platinum(II)-containing poly(arylene ethynylene)s of variable bandgaps (∼1.4-3.0 eV) represent attractive candidates for a cost-effective, lightweight solar-energy conversion platform. This Account highlights and discusses the recent advances of this research frontier in organometallic photovoltaics. The emerging use of low-bandgap soluble platinum-acetylide polymers in PSCs offers a new and versatile strategy to capture sunlight for efficient solar power generation. Properties of these polyplatinynes--including their chemical structures, absorption coefficients, bandgaps, charge mobilities, accessibility of triplet excitons, molecular weights, and blend film morphologies--critically influence the device

  8. Relating ionic liquids and polyethylene glycols to green chemistry, organometallic catalysis, and materials science

    NASA Astrophysics Data System (ADS)

    Klingshirn, Marc Allen

    The field of green chemistry has grown tremendously over the past years due to stricter environmental laws regulating the amount of toxic substances that are legally allowed into the environment. The objective of this work was to incorporate ILs and PEGs into gel type matrices and utilize them as solvent alternatives in hopes of helping advance the field of green chemistry and lowering environmental burden. Here, three new gel-type materials were studied. A PEG gel-silica sol composite and an IL-PEG gel were developed. Both materials were based on a cross-linked PEG hydrogel and its response to various inorganic salts. The new materials developed exhibited the same shrink-swell characteristics as the control PEG hydrogel, while the IL-PEG gel showed similar uptakes of linear alcohols from salt solutions. Additionally, when calcined, the PEG gel-silica sol composite was found to have unique morphologies that were dependent on PEG hydrogel concentration. The third material that was developed was a silica sol gel that was synthesized utilizing 1-butyl-3-methylimidazolium chloride as a (co)solvent. All previous work reported used ILs that had structures similar to surfactants that are traditionally used in creating high surface area materials. The work here presents a fundamental study of how short chained ILs can be used to produce high surface area materials and addresses questions such as how the IL orients itself within the matrix during the sol gel process. Another facet of the work involves the incorporation of ILs and PEGS into organometallic catalytic systems, specifically the hydroesterification of styrene and the copolymerization of styrene and carbon monoxide. The ILs' non-coordinating nature allows them to stabilize catalytically active charged species in addition to allowing for ease of catalyst recycling. The application of the presented work to the field of green chemistry includes the implementation of benign, non-volatile reaction media, specifically

  9. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2010-01-01

    Seawater and natural brines accounted for about 40 percent of U.S. magnesium compounds production in 2009. Dead-burned magnesia was produced by Martin Marietta Magnesia Specialties from well brines in Michigan. Caustic-calcined magnesia was recovered from seawater by Premier Chemicals in Florida, from well brines in Michigan by Martin Marietta and from magnesite in Nevada by Premier Chemicals. Intrepid Potash-Wendover, and Great Salt Lake Minerals Corp. recovered magnesium chloride brines from the Great Salt Lake in Utah. Magnesium hydroxide was produced from seawater by SPI Pharma in Delaware and Premier Chemicals in Florida, and by Martin Marietta from its operation mentioned above.

  10. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2002-01-01

    Seawater and natural brines accounted for about 60% of US magnesium compounds production in 2001. Dead-burned and caustic-calcined magnesias were recovered from seawater in Florida by Premier Chemicals. They were also recovered from Michigan well brines by Dow Chemical, Martin Marietta Magnesia Specialties and Rohm & Haas. And Premier Chemicals recovered dead-burned and caustic-calcined magnesias from magnesite in Nevada. Reilly Industries and Great Salt Lake Minerals recovered magnesium chloride brines from the Great Salt Lake in Utah.

  11. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2011-01-01

    Seawater and natural brines accounted for about 54 percent of U.S. magnesium compounds production in 2010. Dead-burned magnesia was produced by Martin Marietta Magnesia Specialties from well brines in Michigan. Caustic-calcined magnesia was recovered from seawater by Premier Magnesia in Florida, from well brines in Michigan by Martin Marietta and from magnesite in Nevada by Premier Magnesia. Intrepid Potash-Wendover and Great Salt Lake Minerals Corp. recovered magnesium chloride brines from the Great Salt Lake in Utah. Magnesium hydroxide was produced from seawater by SPI Pharma in Delaware and Premier Magnesia in Florida, and by Martin Marietta from its operation mentioned above.

  12. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2007-01-01

    Seawater and natural brines accounted for about 52 percent of U.S. magnesium compounds production in 2006. Dead-burned magnesia was produced by Martin Marietta Magnesia Specialties from well brines in Michigan. Caustic-calcined magnesia was recovered from sea-water by Premier Chemicals in Florida; from well brines in Michigan by Martin Marietta and Rohm and Haas; and from magnesite in Nevada by Premier Chemicals. Intrepid Potash-Wendover and Great Salt Lake Minerals recovered magnesium chloride brines from the Great Salt Lake in Utah. Magnesium hydroxide was produced from brucite by Applied Chemical Magnesias in Texas, from seawater by SPI Pharma in Delaware and Premier Chemicals in Florida, and by Martin Marietta and Rohm and Haas from their operations mentioned above. About 59 percent of the magnesium compounds consumed in the United States was used for refractories that are used mainly to line steelmaking furnaces. The remaining 41 percent was consumed in agricultural, chemical, construction, environmental and industrial applications.

  13. Intermetallic Compounds

    NASA Astrophysics Data System (ADS)

    Takagiwa, Y.; Matsuura, Y.; Kimura, K.

    2014-06-01

    We have focused on the binary narrow-bandgap intermetallic compounds FeGa3 and RuGa3 as thermoelectric materials. Their crystal structure is FeGa3-type (tetragonal, P42/ mnm) with 16 atoms per unit cell. Despite their simple crystal structure, their room temperature thermal conductivity is in the range 4-5-W-m-1-K-1. Both compounds have narrow-bandgaps of approximately 0.3-eV near the Fermi level. Because their Seebeck coefficients are quite large negative values in the range 350-<-| S 373K|-<-550- μV-K-1 for undoped samples, it should be possible to obtain highly efficient thermoelectric materials both by adjusting the carrier concentration and by reducing the thermal conductivity. Here, we report the effects of doping on the thermoelectric properties of FeGa3 and RuGa3 as n and p-type materials. The dimensionless figure of merit, ZT, was significantly improved by substitution of Sn for Ga in FeGa3 (electron-doping) and by substitution of Zn for Ga in RuGa3 (hole-doping), mainly as a result of optimization of the electronic part, S 2 σ.

  14. Spin-State Effects on the Thermal Dihydrogen Release from Solid-State [MH(η(2)-H 2)dppe2](+) (M = Fe, Ru, Os) Organometallic Complexes for Hydrogen Storage Applications.

    PubMed

    Abrecht, David G; Muñoz, Jorge A; Smith, Hillary L; Fultz, Brent

    2014-01-30

    Mössbauer spectroscopy, experimental thermodynamic measurements, and computational studies were performed to investigate the properties of molecular hydrogen binding to the organometallic fragments [MHdppe2](+) (M = Fe, Ru, Os; dppe =1,2-bis(diphenylphosphino)ethane) to form the dihydrogen complex fragments [MH(η(2)-H2)dppe2](+). Mössbauer spectroscopy showed that the dehydrogenated complex [FeHdppe2](+) adopts a geometry consistent with the triplet spin state, transitioning to a singlet state complex upon addition of the dihydrogen molecule in a manner similar to the previously studied dinitrogen complexes. From simulations, this spin transition behavior was found to be responsible for the strong binding behavior experimentally observed in the iron complex. Spin-singlet to spin-singlet transitions were found to exhibit thermodynamics consistent with the 5d > 3d > 4d binding trend observed for other transition metal dihydrogen complexes. Finally, the method for distinguishing between dihydrogen and dihydride complexes based on partial quadrupole splittings observed in Mössbauer spectra was confirmed, providing a tool for further characterization of these unique species for Mössbauer active compounds. PMID:24803973

  15. Spin-State Effects on the Thermal Dihydrogen Release from Solid-State [MH(η2-H2)dppe2]+ (M = Fe, Ru, Os) Organometallic Complexes for Hydrogen Storage Applications

    PubMed Central

    2015-01-01

    Mössbauer spectroscopy, experimental thermodynamic measurements, and computational studies were performed to investigate the properties of molecular hydrogen binding to the organometallic fragments [MHdppe2]+ (M = Fe, Ru, Os; dppe =1,2-bis(diphenylphosphino)ethane) to form the dihydrogen complex fragments [MH(η2-H2)dppe2]+. Mössbauer spectroscopy showed that the dehydrogenated complex [FeHdppe2]+ adopts a geometry consistent with the triplet spin state, transitioning to a singlet state complex upon addition of the dihydrogen molecule in a manner similar to the previously studied dinitrogen complexes. From simulations, this spin transition behavior was found to be responsible for the strong binding behavior experimentally observed in the iron complex. Spin-singlet to spin-singlet transitions were found to exhibit thermodynamics consistent with the 5d > 3d > 4d binding trend observed for other transition metal dihydrogen complexes. Finally, the method for distinguishing between dihydrogen and dihydride complexes based on partial quadrupole splittings observed in Mössbauer spectra was confirmed, providing a tool for further characterization of these unique species for Mössbauer active compounds. PMID:24803973

  16. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2012-01-01

    Seawater and natural brines accounted for about 57 percent of magnesium compounds produced in the United States in 2011. Dead-burned magnesia was produced by Martin Marietta Magnesia Specialties LLC from well brines in Michigan. Caustic-calcined magnesia was recovered from seawater by Premier Magnesia LLC in Florida, from well brines in Michigan by Martin Marietta and from magnesite in Nevada by Premier Magnesia. Intrepid Potash Wendover LLC and Great Salt Lake Minerals Corp. recovered magnesium chloride brines from the Great Salt Lake in Utah. Magnesium hydroxide was produced from seawater by SPI Pharma Inc. in Delaware and Premier Magnesia in Florida, and by Martin Marietta from its brine operation in Michigan.

  17. Bismaleimide compounds

    DOEpatents

    Adams, Johnnie E.; Jamieson, Donald R.

    1986-01-14

    Bismaleimides of the formula ##STR1## wherein R.sub.1 and R.sub.2 each independently is H, C.sub.1-4 -alkyl, C.sub.1-4 -alkoxy, C1 or Br, or R.sub.1 and R.sub.2 together form a fused 6-membered hydrocarbon aromatic ring, with the proviso that R.sub.1 and R.sub.2 are not t-butyl or t-butoxy; X is O, S or Se; n is 1-3; and the alkylene bridging group, optionally, is substituted by 1-3 methyl groups or by fluorine, form polybismaleimide resins which have valuable physical properties. Uniquely, these compounds permit extended cure times, i.e., they remain fluid for a time sufficient to permit the formation of a homogeneous melt prior to curing.

  18. Bismaleimide compounds

    DOEpatents

    Adams, J.E.; Jamieson, D.R.

    1986-01-14

    Bismaleimides of the formula shown in the diagram wherein R[sub 1] and R[sub 2] each independently is H, C[sub 1-4]-alkyl, C[sub 1-4]-alkoxy, Cl or Br, or R[sub 1] and R[sub 2] together form a fused 6-membered hydrocarbon aromatic ring, with the proviso that R[sub 1] and R[sub 2] are not t-butyl or t-butoxy; X is O, S or Se; n is 1--3; and the alkylene bridging group, optionally, is substituted by 1--3 methyl groups or by fluorine, form polybismaleimide resins which have valuable physical properties. Uniquely, these compounds permit extended cure times, i.e., they remain fluid for a time sufficient to permit the formation of a homogeneous melt prior to curing.

  19. Thermodynamic modeling of As and P incorporation In GaxIn1-xPyAs1-y epitaxial layers grown by organometallic vapor phase epitaxy

    NASA Astrophysics Data System (ADS)

    Jordan, A. S.

    1995-11-01

    The quaternary epitaxial film Gaxln1-x As1-y (Q) lattice-matched to InP is the active layer in lasers emitting between 1.1 and 1.55 μm. In this paper, we present a thermodynamic analysis of the group V incorporation in Q layers prepared by organometallic vapor phase epitaxy. We have recently given an equilibrium description of the combined pyrolysis of AsH3 and PH3 for any input flow rate and H2 dilution as a function of growth temperature and total pressure, ptot. To extend the treatment to gas-solid equilibrium, the Q solid is considered to be a quaternary regular solution subject to the constraint of mixing on both sublattices, for which activities were previously published. Knowing the free-energy of formation of the four bounding binary compounds, a root for yp at a given temperature, input flow rates and ptot is obtained by iteration that stops at values ofP_{As_4 } andP_{P_4 } simultaneously satisfying the free-energies of formation and the gas flow material balance as well as the site conservation constraint. At a constant ptot in complete thermodynamic equilibrium, yp slowly increases with temperature (800 1200K). Taking into account the incomplete decomposition of PH3 and considering the undecomposed fraction of PH3 as an “inert” gas, the analysis shows a rapid rise in yp with temperature in the deposition zone. Clearly, to attain the desirable thermodynamic regime at, say, ˜650°C, the use of an alternative source, such as tertiarybutylphosphine, is desirable. We present the solid composition, yp, as a function of temperature and PH3 flow rate for realistic parameters for Q materials emitting between 1.1 1.55 urn. We also show the predicted lattice mismatch and emission wavelength associated with yp. A preliminary comparison with experimental data obtained in our laboratory is in reasonable accord with the calculated results.

  20. Inhibition of the p53/hDM2 protein-protein interaction by cyclometallated iridium(III) compounds

    PubMed Central

    Liu, Li-Juan; He, Bingyong; Miles, Jennifer A.; Wang, Wanhe; Mao, Zhifeng; Che, Weng Ian; Lu, Jin-Jian; Chen, Xiu-Ping; Wilson, Andrew J.; Ma, Dik-Lung; Leung, Chung-Hang

    2016-01-01

    Inactivation of the p53 transcription factor by mutation or other mechanisms is a frequent event in tumorigenesis. One of the major endogenous negative regulators of p53 in humans is hDM2, a ubiquitin E3 ligase that binds to p53 causing proteasomal p53 degradation. In this work, a library of organometallic iridium(III) compounds were synthesized and evaluated for their ability to disrupt the p53/hDM2 protein-protein interaction. The novel cyclometallated iridium(III) compound 1 [Ir(eppy)2(dcphen)](PF6) (where eppy = 2-(4-ethylphenyl)pyridine and dcphen = 4, 7-dichloro-1, 10-phenanthroline) blocked the interaction of p53/hDM2 in human amelanotic melanoma cells. Finally, 1 exhibited anti-proliferative activity and induced apoptosis in cancer cell lines consistent with inhibition of the p53/hDM2 interaction. Compound 1 represents the first reported organometallic p53/hDM2 protein-protein interaction inhibitor. PMID:26883110