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Sample records for phosphines

  1. Phosphine

    Integrated Risk Information System (IRIS)

    Phosphine ; CASRN 7803 - 51 - 2 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Effect

  2. Mechanisms of Phosphine Toxicity

    PubMed Central

    Nath, Nisa S.; Bhattacharya, Ishita; Tuck, Andrew G.; Schlipalius, David I.; Ebert, Paul R.

    2011-01-01

    Fumigation with phosphine gas is by far the most widely used treatment for the protection of stored grain against insect pests. The development of high-level resistance in insects now threatens its continued use. As there is no suitable chemical to replace phosphine, it is essential to understand the mechanisms of phosphine toxicity to increase the effectiveness of resistance management. Because phosphine is such a simple molecule (PH3), the chemistry of phosphorus is central to its toxicity. The elements above and below phosphorus in the periodic table are nitrogen (N) and arsenic (As), which also produce toxic hydrides, namely, NH3 and AsH3. The three hydrides cause related symptoms and similar changes to cellular and organismal physiology, including disruption of the sympathetic nervous system, suppressed energy metabolism and toxic changes to the redox state of the cell. We propose that these three effects are interdependent contributors to phosphine toxicity. PMID:21776261

  3. Confirmation of Circumstellar Phosphine

    NASA Astrophysics Data System (ADS)

    Agúndez, M.; Cernicharo, J.; Decin, L.; Encrenaz, P.; Teyssier, D.

    2014-08-01

    Phosphine (PH3) was tentatively identified a few years ago in the carbon star envelopes IRC +10216 and CRL 2688 from observations of an emission line at 266.9 GHz attributable to the J = 1-0 rotational transition. We report the detection of the J = 2-1 rotational transition of PH3 in IRC +10216 using the HIFI instrument on board Herschel, which definitively confirms the identification of PH3. Radiative transfer calculations indicate that infrared pumping in excited vibrational states plays an important role in the excitation of PH3 in the envelope of IRC +10216, and that the observed lines are consistent with phosphine being formed anywhere between the star and 100 R * from the star, with an abundance of 10-8 relative to H2. The detection of PH3 challenges chemical models, none of which offer a satisfactory formation scenario. Although PH3 holds just 2% of the total available phosphorus in IRC +10216, it is, together with HCP, one of the major gas phase carriers of phosphorus in the inner circumstellar layers, suggesting that it could also be an important phosphorus species in other astronomical environments. This is the first unambiguous detection of PH3 outside the solar system, and is a further step toward a better understanding of the chemistry of phosphorus in space.

  4. CONFIRMATION OF CIRCUMSTELLAR PHOSPHINE

    SciTech Connect

    Agúndez, M.; Cernicharo, J.; Encrenaz, P.; Teyssier, D.

    2014-08-01

    Phosphine (PH{sub 3}) was tentatively identified a few years ago in the carbon star envelopes IRC +10216 and CRL 2688 from observations of an emission line at 266.9 GHz attributable to the J = 1-0 rotational transition. We report the detection of the J = 2-1 rotational transition of PH{sub 3} in IRC +10216 using the HIFI instrument on board Herschel, which definitively confirms the identification of PH{sub 3}. Radiative transfer calculations indicate that infrared pumping in excited vibrational states plays an important role in the excitation of PH{sub 3} in the envelope of IRC +10216, and that the observed lines are consistent with phosphine being formed anywhere between the star and 100 R {sub *} from the star, with an abundance of 10{sup –8} relative to H{sub 2}. The detection of PH{sub 3} challenges chemical models, none of which offer a satisfactory formation scenario. Although PH{sub 3} holds just 2% of the total available phosphorus in IRC +10216, it is, together with HCP, one of the major gas phase carriers of phosphorus in the inner circumstellar layers, suggesting that it could also be an important phosphorus species in other astronomical environments. This is the first unambiguous detection of PH{sub 3} outside the solar system, and is a further step toward a better understanding of the chemistry of phosphorus in space.

  5. Phosphonate–Phosphinate Rearrangement

    PubMed Central

    2014-01-01

    LiTMP metalated dimethyl N-Boc-phosphoramidates derived from 1-phenylethylamine and 1,2,3,4-tetrahydronaphthalen-1-ylamine highly selectively at the CH3O group to generate short-lived oxymethyllithiums. These isomerized to diastereomeric hydroxymethylphosphonamidates (phosphate–phosphonate rearrangement). However, s-BuLi converted the dimethyl N-Boc-phosphoramidate derived from 1-phenylethylamine to the N-Boc α-aminophosphonate preferentially. Only s-BuLi deprotonated dimethyl hydroxymethylphosphonamidates at the benzylic position and dimethyl N-Boc α-aminophosphonates at the CH3O group to induce phosphonate–phosphinate rearrangements. In the former case, the migration of the phosphorus substituent from the nitrogen to the carbon atom followed a retentive course with some racemization because of the involvement of a benzyllithium as an intermediate. PMID:25525945

  6. Phosphine oxide surfactants revisited.

    PubMed

    Stubenrauch, Cosima; Preisig, Natalie; Laughlin, Robert G

    2016-04-01

    This review summarizes everything we currently know about the nonionic surfactants alkyl dimethyl (CnDMPO) and alkyl diethyl (CnDEPO) phosphine oxide (PO surfactants). The review starts with the synthesis and the general properties (Section 2) of these compounds and continues with their interfacial properties (Section 3) such as surface tension, surface rheology, interfacial tension and adsorption at solid surfaces. We discuss studies on thin liquid films and foams stabilized by PO surfactants (Section 4) as well as studies on their self-assembly into lyotropic liquid crystals and microemulsions, respectively (Section 5). We aim at encouraging colleagues from both academia and industry to take on board PO surfactants whenever possible and feasible because of their broad variety of excellent properties. PMID:26869216

  7. Simple unprecedented conversion of phosphine oxides and sulfides to phosphine boranes using sodium borohydride.

    PubMed

    Rajendran, Kamalraj V; Gilheany, Declan G

    2012-01-21

    A variety of phosphine oxides and sulfides can be efficiently converted directly to the corresponding phosphine boranes using oxalyl chloride followed by sodium borohydride. Optically active P-stereogenic phosphine oxides can be converted stereospecifically to phosphine boranes with inversion of configuration by treatment with Meerwein's salt followed by sodium borohydride. PMID:22022704

  8. Chiral phosphines in nucleophilic organocatalysis

    PubMed Central

    Xiao, Yumei; Sun, Zhanhu

    2014-01-01

    Summary This review discusses the tertiary phosphines possessing various chiral skeletons that have been used in asymmetric nucleophilic organocatalytic reactions, including annulations of allenes, alkynes, and Morita–Baylis–Hillman (MBH) acetates, carbonates, and ketenes with activated alkenes and imines, allylic substitutions of MBH acetates and carbonates, Michael additions, γ-umpolung additions, and acylations of alcohols. PMID:25246969

  9. Phosphine Catalysis of Allenes with Electrophiles

    PubMed Central

    Wang, Zhiming; Xu, Xingzhu; Kwon, Ohyun

    2014-01-01

    Nucleophilic phosphine catalysis of allenes with electrophiles is one of the most powerful and straightforward synthetic strategies for the generation of highly functionalized carbocycle or heterocycle structural motifs, which are present in a wide range of bioactive natural products and medicinally important substances. The reaction topologies can be controlled through judicious choice of the phosphine catalyst and the structural variations of starting materials. This Tutorial Review presents selected examples of nucleophilic phosphine catalysis using allenes and electrophiles. PMID:24663290

  10. Phosphine photochemistry in Saturn's atmosphere

    NASA Astrophysics Data System (ADS)

    Kaye, J. A.; Strobel, D. F.

    1983-10-01

    The phosphine photochemistry on Saturn is studied with a 1D photochemical model. The PH3 concentration is rapidly depleted with height (scale height 3.5 km) in the upper troposphere. Formation of P, a probable precursor of P4, (a potential red chromophore in the atmosphere), is highly improbable unless the rate constant for the recombination reaction PH + H2 + M yields PH3 + M is less than 10 to the -41st cm exp 6/molecule-squared sec. Coupling of PH3 and hydrocarbon photochemistry, specifically the C2H2 catalyzed photodissociation of CH, is important. Column production rates of the organophosphorus compounds CH3PH2 and HCP of 3 x 10 to the 8th/sq cm sec are predicted, with potentially observable column densities of greater than 1 x 10 to the 17th/sq cm.

  11. Phosphine photochemistry in Saturn's atmosphere

    NASA Technical Reports Server (NTRS)

    Kaye, J. A.; Strobel, D. F.

    1983-01-01

    The phosphine photochemistry on Saturn is studied with a 1D photochemical model. The PH3 concentration is rapidly depleted with height (scale height 3.5 km) in the upper troposphere. Formation of P, a probable precursor of P4, (a potential red chromophore in the atmosphere), is highly improbable unless the rate constant for the recombination reaction PH + H2 + M yields PH3 + M is less than 10 to the -41st cm exp 6/molecule-squared sec. Coupling of PH3 and hydrocarbon photochemistry, specifically the C2H2 catalyzed photodissociation of CH, is important. Column production rates of the organophosphorus compounds CH3PH2 and HCP of 3 x 10 to the 8th/sq cm sec are predicted, with potentially observable column densities of greater than 1 x 10 to the 17th/sq cm.

  12. [Phosphinic analog of methionine inhibits growth of leucosis cell L1210 and transforms to phosphinic analog of S-adenosylmethionine].

    PubMed

    Khomutov, R M; Zhukov, Iu N; Khomutov, A R; Khurs, E N; Kramer, D L; Miller, J T; Porter, C W

    2000-09-01

    A phosphinic analogue of methionine bearing a phosphinic H(OH)(O)P fragment in place of the carboxyl group inhibited the growth of the L1210 cells and was intracellularly transformed to the phosphinic analogue of S-adenosylmethionine. PMID:11036532

  13. CYTOGENETIC EFFECTS OF PHOSPHINE INHALATION BY RODENTS

    EPA Science Inventory

    Phosphine (PH3) is a highly toxic grain fumigant that can be produced from the reaction of metal phosphides with water. o determine the in vivo cytogenetic effects of inhalation of PH3, male CD-1 mice were exposed to either 0, 5, 10, or 15 ppm target concentrations of PH3 for 6 h...

  14. Reducing injury of lettuce from phosphine fumigation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Low temperature fumigation with pure phosphine free of ammonia has been used in recent years for postharvest pest control on some fresh fruits and vegetables. However, long fumigation treatments cause injuries to lettuce. It is unknown what factors contributed to the injuries. It is important to min...

  15. Palladium-Catalyzed α-Arylation of Benzylic Phosphine Oxides

    PubMed Central

    Montel, Sonia; Jia, Tiezheng

    2014-01-01

    A novel approach to prepare diarylmethyl phosphine oxides from benzyl phosphine oxides via deprotonative cross-coupling processes (DCCP) is reported. The optimization of the reaction was guided by High-Throughput Experimentation (HTE) techniques. The Pd(OAc)2/Xantphos-based catalyst enabled the reaction between benzyl diphenyl or dicyclohexyl phosphine oxide derivatives and aryl bromides in good to excellent yields (51–91%). PMID:24295336

  16. Phosphinate inhibitor for scale squeeze applications

    SciTech Connect

    Pardue, J.E.; Kneller, J.F.

    1991-05-28

    This patent describes an improved squeeze treatment for preventing and removing scale from the surfaces of oil wells and the formations adjacent to the casing of these wells, the squeeze treatment being of the type wherein the injection of the flood water is stopped, a solution containing scale inhibitor is introduced under increased pressure into the wellbore penetrating the formation adjacent to the wellbore. The improvement comprises: using as the scale inhibitor a predominantly phosphinate containing composition.

  17. Perfluoropropenyl-containing phosphines from HFC replacements.

    PubMed

    Brisdon, Alan K; Ali Ghaba, Hana; Beutel, Bernd; Ejgandi, Amina; Egjandi, Amina; Addaraidi, Arij; Pritchard, Robin G

    2015-12-01

    A series of new perfluoropropenyl-containing phosphines of the type R3-nP(E-CF[double bond, length as m-dash]CFCF3)n (R = Ph, iPr, n = 1, 2; R = tBu, n = 2) have been prepared from the reaction of the hydrofluoroolefin Z-CF3CF[double bond, length as m-dash]CFH (HFO-1225ye) with base and the appropriate chlorophosphine, while reaction with Cl2PCH2CH2PCl2 gave (CF3CF[double bond, length as m-dash]CF)2PCH2CH2P(CF[double bond, length as m-dash]CFCF3)2, the first example of a bidentate perfluoroalkenyl-containing phosphine. An alternative route to these phosphines based on the room- or low-temperature deprotonation of CF3CF2CH2F (HFC-236ea) gives mainly the E-isomer, but also a small amount of the Z-isomer, the ratio of which depends on the reaction temperature. All of the phosphines could be readily oxidised with either H2O2 or urea·H2O2, and the phosphine selenides R3-nP(Se)(E-CF[double bond, length as m-dash]CFCF3)n (R = Ph, n = 1,2; R = iPr, n = 1; R = tBu, n = 2) were also prepared. The steric and electronic properties of these ligands were determined based on their platinum(ii), palladium(ii) and molybdenum carbonyl complexes. The crystal structures of (CF3CF[double bond, length as m-dash]CF)2PCH2CH2P(CF[double bond, length as m-dash]CFCF3)2, (CF3CF[double bond, length as m-dash]CF)2P(O)CH2CH2P(O)(CF[double bond, length as m-dash]CFCF3)2, iPr2P(Se)(CF[double bond, length as m-dash]CFCF3)2, trans-[PtCl2{Ph(3-n)P(E-CF[double bond, length as m-dash]CFCF3)n}2] (n = 1 or 2), trans-[PdCl2{R2P(E-CF[double bond, length as m-dash]CFCF3)}2] (R = Ph, iPr) and [Mo(CO)4{(CF3CF[double bond, length as m-dash]CF)2PCH2CH2P(CF[double bond, length as m-dash]CFCF3)2}] are reported. PMID:26212860

  18. Preparation of phosphines through C–P bond formation

    PubMed Central

    Wauters, Iris; Debrouwer, Wouter

    2014-01-01

    Summary Phosphines are an important class of ligands in the field of metal-catalysis. This has spurred the development of new routes toward functionalized phosphines. Some of the most important C–P bond formation strategies were reviewed and organized according to the hybridization of carbon in the newly formed C–P bond. PMID:24991257

  19. Phosphine and phosphine oxide groups in metal-organic frameworks detected by P K-edge XAS.

    PubMed

    Morel, F L; Pin, S; Huthwelker, T; Ranocchiari, M; van Bokhoven, J A

    2015-02-01

    Phosphine metal-organic frameworks (P-MOFs) are crystalline porous coordination polymers that contain phosphorus functional groups within their pores. We present the use of X-ray absorption spectroscopy (XAS) at the P K-edge to determine the phosphine to phosphine oxide ratio in two P-MOFs with MIL-101 topology. The phosphorus oxidation state is of particular interest as it strongly influences the coordination affinity of these materials for transition metals. This method can determine the oxidation state of phosphorus even when the material contains paramagnetic nuclei, differently from NMR spectroscopy. We observed that phosphine in LSK-15 accounts for 72 ± 4% of the total phosphorus groups and that LSK-12 contains only phosphine oxide. PMID:25523824

  20. Comparison of Aromatic Dithio-phosphinic and Phosphinic Acid Derivatives for Minor Actinide Extraction

    SciTech Connect

    Harrup, Mason K.; Peterman, Dean R.; Greenhalgh, Mitchell R.; Luther, Thomas A.; Klaehn, John

    2008-07-01

    A new extractant for the separation of actinide(III) and lanthanide(III), bis(o-trifluoromethylphenyl) phosphinic acid (O-PA) was synthesized. The synthetic route employed mirrors one that was employed to produce the sulfur containing analog bis(o-trifluoromethylphenyl) dithio-phosphinic acid (S-PA). Multinuclear NMR spectroscopy was used for elementary characterization of the new O-PA derivative. This new O-PA extractant was used to perform Am(III)/Eu(III) separations and the results were directly compared to those obtained in identical separation experiments using S-PA, an extractant that is known to exhibit separation factors of {approx}100,000 at low pH. The separations data are presented and discussed in terms comparing the nature of the oxygen atom as a donor to that of the sulfur atom in extractants that are otherwise identical. (authors)

  1. Mitsunobu Reactions Catalytic in Phosphine and a Fully Catalytic System

    PubMed Central

    Buonomo, Joseph A; Aldrich, Courtney C

    2015-01-01

    The Mitsunobu reaction is renowned for its mild reaction conditions and broad substrate tolerance, but has limited utility in process chemistry and industrial applications due to poor atom economy and the generation of stoichiometric phosphine oxide and hydrazine by-products that complicate purification. A catalytic Mitsunobu reaction using innocuous reagents to recycle these by-products would overcome both of these shortcomings. Herein we report a protocol that is catalytic in phosphine (1-phenylphospholane) employing phenylsilane to recycle the catalyst. Integration of this phosphine catalytic cycle with Taniguchi’s azocarboxylate catalytic system provided the first fully catalytic Mitsunobu reaction. PMID:26347115

  2. Hydroxyalkyl phosphine compounds for use as diagnostic and therapeutic pharmaceuticals

    DOEpatents

    Katti, K.V.; Singh, P.R.; Reddy, V.S.; Katti, K.K.; Volkert, W.A.; Ketring, A.R.

    1999-03-02

    This research discloses a compound and method of making a compound for use as a diagnostic or therapeutic pharmaceutical comprises a functionalized hydroxyalkyl phosphine ligand and a metal combined with the ligand. 16 figs.

  3. Imide/Arylene Ether Copolymers Containing Phosphine Oxide

    NASA Technical Reports Server (NTRS)

    Jensen, Brian J.; Partos, Richard D.

    1993-01-01

    Phosphine oxide groups react with oxygen to form protective phosphate surface layers. Series of imide/arylene ether block copolymers containing phosphine oxide units in backbone synthesized and characterized. In comparison with commercial polyimide, these copolymers display better resistance to etching by oxygen plasma. Tensile strengths and tensile moduli greater than those of polyarylene ether homopolymer. Combination of properties makes copolymers attractive for films, coatings, adhesives, and composite matrices where resistance to atomic oxygen needed.

  4. Genes related to mitochondrial are differentially expressed in phosphine-resistant and -susceptible Tribolium castaneum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phosphine is a valuable fumigant to control pest populations in stored grains and grain products. However, recent studies indicate a substantial increase in phosphine resistance in major stored-cereal pests worldwide. To understand the molecular bases of phosphine resistance in insects, we used RNA-...

  5. Comparative Toxicity of Fumigants and a Phosphine Synergist Using a Novel Containment Chamber for the Safe Generation of Concentrated Phosphine Gas

    PubMed Central

    Valmas, Nicholas; Ebert, Paul R.

    2006-01-01

    Background With the phasing out of ozone-depleting substances in accordance with the United Nations Montreal Protocol, phosphine remains as the only economically viable fumigant for widespread use. However the development of high-level resistance in several pest insects threatens the future usage of phosphine; yet research into phosphine resistance mechanisms has been limited due to the potential for human poisoning in enclosed laboratory environments. Principal Findings Here we describe a custom-designed chamber for safely containing phosphine gas generated from aluminium phosphide tablets. In an improvement on previous generation systems, this chamber can be completely sealed to control the escape of phosphine. The device has been utilised in a screening program with C. elegans that has identified a phosphine synergist, and quantified the efficacy of a new fumigant against that of phosphine. The phosphine-induced mortality at 20°C has been determined with an LC50 of 732 ppm. This result was contrasted with the efficacy of a potential new botanical pesticide dimethyl disulphide, which for a 24 hour exposure at 20°C is 600 times more potent than phosphine (LC50 1.24 ppm). We also found that co-administration of the glutathione depletor diethyl maleate (DEM) with a sublethal dose of phosphine (70 ppm, phosphine in a laboratory environment has now been substantially reduced by the implementation of our novel gas generation chamber. We have also identified a novel phosphine synergist, the glutathione depletor DEM, suggesting an effective pathway to be targeted in future synergist research; as well as quantifying the efficacy of a potential alternative to phosphine, dimethyl disulphide. PMID:17205134

  6. Mechanism of phosphine borane deprotection with amines: the effects of phosphine, solvent and amine on rate and efficiency.

    PubMed

    Lloyd-Jones, Guy C; Taylor, Nicholas P

    2015-03-27

    The kinetics of borane transfer from simple tertiary phosphine borane adducts to a wide range of amines have been determined. All data obtained, including second-order kinetics, lack of cross-over, and negative entropies of activation for reaction of triphenylphosphine borane with quinuclidine and triethylamine, are consistent with a direct (SN 2-like) transfer process, rather than a dissociative (SN 1-like) process. The identities of the amine, phosphine, and solvent all impact substantially on the rate (k) and equilibrium (K) of the transfer, which in some cases vary by many orders of magnitude. P-to-N transfer is more efficient with cyclic amines in apolar solvents due to reduced entropic costs and ground-state destabilisation. Taken as a whole, the data allow informed optimisation of the deprotection step from the stand-point of rate, or synthetic convenience. In all cases, both reactants should be present at high initial concentration to gain kinetic benefit from the bimolecularity of the process. Ultimately, the choice of amine is dictated by the identity of the phosphine borane complex. Aryl-rich phosphine boranes are sufficiently reactive to allow use of diethylamine or pyrrolidine as a volatile low polarity solvent and reactant, whereas more alkyl-rich phosphines benefit from the use of more reactive amines, such as 1,4-diaza[2.2.2]bicyclooctane (DABCO), in apolar solvents at higher temperatures. PMID:25704230

  7. Phosphinic peptides as potent inhibitors of zinc-metalloproteases.

    PubMed

    Georgiadis, Dimitris; Dive, Vincent

    2015-01-01

    The development of transition-state analogs is a major objective in enzymology, not only for developing potent inhibitors of enzymes but also for dissecting enzyme catalytic mechanisms. Phosphinic peptides, which share closed structural similarities with the transition-state of peptide substrate upon hydrolysis, have thus been considered for identifying potent inhibitors of proteases. Focusing on the zinc-proteases family, this review presents the most important synthetic efforts performed to obtain the desired compounds. Crystal structures of the phosphinic peptides in interaction with their zinc-protease targets are reported to illustrate the structural features which may explain the potency of these compounds and how they contribute to uncover key enzyme catalytic residues. Based on a remarkable metabolic stability, phosphinic peptides can be used to probe the in vivo function of zinc-proteases. Progress on chemistry and better understanding on the functional roles of zinc-proteases should allow transferring these compounds from shelf to clinic. PMID:25370521

  8. Resistance of Lasioderma serricorne (Coleoptera: Anobiidae) to Fumigation with Phosphine.

    PubMed

    Sağlam, Özgür; Edde, Peter A; Phillips, Thomas W

    2015-10-01

    Lasioderma serricorne (F.) is a serious pest of stored products that is known to be resistant to the fumigant pesticide gas phosphine. This study investigated resistance in populations from the southeastern United States, and determined if a recommended treatment schedule could kill resistant insects. A laboratory assay for adult insects was developed that used a discriminating concentration of 50 ppm phosphine applied to insects for 20 h at 25°C followed by 7 d of recovery in air. Survivors were classified as resistant. L. serricorne from six different field populations associated with stored tobacco were surveyed with the assay and all had resistant individuals. Four populations had greater than 90% of their insects resistant. Two industry-recommended treatment schedules were evaluated in laboratory fumigations against mixed life stage cultures of the four most resistant populations: the first at 200 ppm for 4 d at 25°C for controlling phosphine-susceptible L. serricorne and the second at 600 ppm for 6 d at 25°C intended to control phosphine-resistant beetles. The four populations with the highest frequency of resistant individuals from the field sampling study were not controlled by the "normal" treatment intended for susceptible insects. The higher concentration treatment greatly reduced beetle progeny from mixed-stage colony jars, but there were substantial numbers of surviving adults from all four highly resistant populations that represented unacceptable levels of control. PMID:26453739

  9. Characterizing Exoplanet Atmospheres : A Complete Line List for Phosphine

    NASA Astrophysics Data System (ADS)

    Sousa-Silva, C.; Yurchenko, S. N.; Tennyson, J.

    2013-09-01

    The ability to characterise the atmospheres of cool stars, brown dwarfs and exoplanets requires fundamental data for all species contributing significantly to their opacity. However, with notable exceptions such as water and ammonia, existing molecular line lists are not sufficiently accurate or complete to allow for a full spectroscopic analysis of these bodies. ExoMol (www.exomol.com [1]) is a project that aims to rectify this by generating comprehensive line lists for all molecules likely to be detected in the atmospheres of cool astrophysical objects in the foreseeable future. The spectral data is generated by employing ab initio quantum mechanical methods, performing empirical refinement based on experimental spectroscopic data and harnessing high performance computing. Here we present our work on phosphine, (PH3), an equilateral pyramidal molecule (the phosphorus analogue to ammonia). Phosphine is known to be important for the atmospheres of giant-planets, cool stars and many other astronomical bodies. Rotational transition features of phosphine have been found in the far- infrared spectra of Saturn and Jupiter [2, 3], where it is a marker for vertical convection zones. A computed room temperature line list of phosphine is presented here [4], illustrated in the accompanying figure 1. This line list is a precursor to a high temperature equivalent to be produced in the near future, necessary for the analysis of cool stars and brown dwarfs. All the transitions' energy levels and Einstein A-coefficients were computed using the program TROVE [5].

  10. Submicromolar Phosphinic Inhibitors of E. coli Aspartate Transcarbamoylase

    PubMed Central

    Coudray, Laëtitia; Kantrowitz, Evan R.; Montchamp, Jean-Luc

    2009-01-01

    The design, syntheses, and enzymatic activity of two submicromolar competitive inhibitors of aspartate transcarbamoylase (ATCase) are described. The phosphinate inhibitors are analogs of N-phosphonacetyl-L-aspartate (PALA) but have a reduced charge at the phosphorus moiety. The mechanistic implications are discussed in terms of a possible cyclic transition-state during enzymatic catalysis. PMID:19097895

  11. Aerobic addition of secondary phosphine oxides to vinyl sulfides: a shortcut to 1-hydroxy-2-(organosulfanyl)ethyl(diorganyl)phosphine oxides

    PubMed Central

    Malysheva, Svetlana F; Artem’ev, Alexander V; Gusarova, Nina K; Belogorlova, Nataliya A; Albanov, Alexander I; Liu, C W

    2015-01-01

    Summary Secondary phosphine oxides react with vinyl sulfides (both alkyl- and aryl-substituted sulfides) under aerobic and solvent-free conditions (80 °C, air, 7–30 h) to afford 1-hydroxy-2-(organosulfanyl)ethyl(diorganyl)phosphine oxides in 70–93% yields. PMID:26664618

  12. Henry's law constant for phosphine in seawater: determination and assessment of influencing factors

    NASA Astrophysics Data System (ADS)

    Fu, Mei; Yu, Zhiming; Lu, Guangyuan; Song, Xiuxian

    2013-07-01

    The Henry's Law constant ( k) for phosphine in seawater was determined by multiple phase equilibration combined with headspace gas chromatography. The effects of pH, temperature, and salinity on k were studied. The k value for phosphine in natural seawater was 6.415 at room temperature (approximately 23°C). This value increases with increases in temperature and salinity, but no obvious change was observed at different pH levels. At the same temperature, there was no significant difference between the k for phosphine in natural seawater and that in artificial seawater. This implies that temperature and salinity are major determining factors for k in marine environment. Double linear regression with Henry's Law constants for phosphine as a function of temperature and salinity confirmed our observations. These results provide a basis for the measurement of trace phosphine concentrations in seawater, and will be helpful for future research on the status of phosphine in the oceanic biogeochemical cycle of phosphorus.

  13. Experimental and theoretical investigations of the stereoselective synthesis of p-stereogenic phosphine oxides.

    PubMed

    Copey, Laurent; Jean-Grard, Ludivine; Framery, Eric; Pilet, Guillaume; Robert, Vincent; Andrioletti, Bruno

    2015-06-15

    An efficient enantioselective strategy for the synthesis of variously substituted phosphine oxides has been developed, incorporating the use of (1S,2S)-2-aminocyclohexanol as the chiral auxiliary. The method relies on three key steps: 1)?Highly diastereoselective formation of P(V) oxazaphospholidine, rationalized by a theoretical study; 2)?highly diastereoselective ring-opening of the oxazaphospholidine oxide with organometallic reagents that takes place with inversion of configuration at the P atom; 3)?enantioselective synthesis of phosphine oxides by cleavage of the remaining P-O bond. Interestingly, the use of a P(III) phosphine precursor afforded a P-epimer oxazaphospholidine. Hence, the two enantiomeric phosphine oxides can be synthesized starting from either a P(V) or a P(III) phosphine precursor, which constitutes a clear advantage for the stereoselective synthesis of sterically hindered phosphine oxides. PMID:25980800

  14. Oxygen plasma resistant phosphine oxide containing imide/arylene copolymers

    NASA Technical Reports Server (NTRS)

    Jensen, Brian J.

    1993-01-01

    A series of oxygen plasma resistant imide/arylene ether copolymers were prepared by reacting anhydride-terminated poly(amide acids) and amine-terminated polyarylene ethers containing phosphine oxide units. Inherent viscosities for these copolymers ranged from 0.42 to 0.80 dL/g. After curing, the resulting copolymers had glass transition temperatures ranging from 224 C to 228 C. Solution cast films of the block copolymers were tough and flexible with tensile strength, tensile moduli, and elongation at break up to 16.1 ksi, 439 ksi, and 23 percent, respectively at 25 C and 9.1 ksi, 308 ksi and 97 percent, respectively at 150 C. The copolymers show a significant improvement in resistance to oxygen plasma when compared to the commercial polyimide Kapton. The imide/arylene ether copolymers containing phosphine oxide units are suitable as coatings, films, adhesives, and composite matrices.

  15. Rhodium catalysed hydroformylation of alkenes using highly fluorophilic phosphines.

    PubMed

    Adams, Dave J; Bennett, James A; Cole-Hamilton, David J; Hope, Eric G; Hopewell, Jonathan; Kight, Jo; Pogorzelec, Peter; Stuart, Alison M

    2005-12-21

    Highly fluorophilic phosphines incorporating at least one aromatic ring containing two directly attached perfluoroalkyl groups have been synthesised, their partition coefficients (organic phase : fluorous phase) measured and their electronic properties probed using (1)J(PtP) data for their trans-[PtCl(2)L(2)] complexes. These phosphines have been used as modifying ligands for the rhodium catalysed hydroformylation of 1-octene in perfluorocarbon solvents. Catalyst activity, regioselectivity and the levels of rhodium leaching to the product phase vary with the substitution patterns of the modifying ligands that do not correlate with the electronic properties or partition coefficients of these ligands, but can be interpreted in terms of differences in the resting states of the catalysts. PMID:16311639

  16. Action of phosphine on production of aflatoxins by various Aspergillus strains isolated from foodstuffs.

    PubMed Central

    Leitao, J; de Saint-Blanquat, G; Bailly, J R

    1987-01-01

    Phosphine is a food fumigant, used until now as an insecticide and rodenticide. The present work researches the action of phosphine treatment on growth and aflatoxin production of 23 Aspergillus strains. Production of aflatoxins B1, B2, G1, and G2 decreased in almost all cases by a ratio of 10 to 100. Phosphine treatment therefore seems favorable to prevent growth of various Aspergillus strains, in the context of keeping food safe. PMID:3426212

  17. Retrievals of Jovian Tropospheric Phosphine from Cassini/CIRS

    NASA Technical Reports Server (NTRS)

    Irwin, P. G. J.; Parrish, P.; Fouchet, T.; Calcutt, S. B.; Taylor, F. W.; Simon-Miller, A. A.; Nixon, C. A.

    2004-01-01

    On December 30th 2000, the Cassini-Huygens spacecraft reached the perijove milestone on its continuing journey to the Saturnian system. During an extended six-month encounter, the Composite Infrared Spectrometer (CIRS) returned spectra of the Jovian atmosphere, rings and satellites from 10-1400 cm(exp -1) (1000-7 microns) at a programmable spectral resolution of 0.5 to 15 cm(exp -1). The improved spectral resolution of CIRS over previous IR instrument-missions to Jupiter, the extended spectral range, and higher signal-to-noise performance provide significant advantages over previous data sets. CIRS global observations of the mid-infrared spectrum of Jupiter at medium resolution (2.5 cm(exp -1)) have been analysed both with a radiance differencing scheme and an optimal estimation retrieval model to retrieve the spatial variation of phosphine and ammonia fractional scale height in the troposphere between 60 deg S and 60 deg N at a spatial resolution of 6 deg. The ammonia fractional scale height appears to be high over the Equatorial Zone (EZ) but low over the North Equatorial Belt (NEB) and South Equatorial Belt (SEB) indicating rapid uplift or strong vertical mixing in the EZ. The abundance of phosphine shows a similar strong latitudinal variation which generally matches that of the ammonia fractional scale height. However while the ammonia fractional scale height distribution is to a first order symmetric in latitude, the phosphine distribution shows a North/South asymmetry at mid latitudes with higher amounts detected at 40 deg N than 40 deg S. In addition the data show that while the ammonia fractional scale height at this spatial resolution appears to be low over the Great Red Spot (GRS), indicating reduced vertical mixing above the approx. 500 mb level, the abundance of phosphine at deeper levels may be enhanced at the northern edge of the GRS indicating upwelling.

  18. Phosphine-mediated Highly Enantioselective Spirocyclization with Ketimines as Substrates.

    PubMed

    Han, Xiaoyu; Chan, Wai-Lun; Yao, Weijun; Wang, Yongjiang; Lu, Yixin

    2016-05-23

    Phosphine-catalyzed enantioselective annulation reactions involving ketimines are a daunting synthetic challenge owing to the intrinsic low reactivity of ketimine substrates. A highly enantioselective [3+2] cycloaddition reaction that makes use of isatin-derived ketimines as reaction partners was developed. Notably, both simple and γ-substituted allenoates could be utilized, and various 3,2'-pyrrolidinyl spirooxindoles with a tetrasubstituted stereocenter were obtained in excellent yields and with nearly perfect enantioselectivity (>98 % ee in all cases). PMID:27080309

  19. Retrievals of jovian tropospheric phosphine from Cassini/CIRS

    NASA Astrophysics Data System (ADS)

    Irwin, P. G. J.; Parrish, P.; Fouchet, T.; Calcutt, S. B.; Taylor, F. W.; Simon-Miller, A. A.; Nixon, C. A.

    2004-11-01

    On December 30th, 2000, the Cassini-Huygens spacecraft reached the perijove milestone on its continuing journey to the Saturnian System. During an extended six-month encounter, the Composite Infrared Spectrometer (CIRS) returned spectra of the jovian atmosphere, rings and satellites from 10-1400 cm -1 (1000-7 μm) at a programmable spectral resolution of 0.5 to 15 cm -1. The improved spectral resolution of CIRS over previous IR instrument-missions to Jupiter, the extended spectral range, and higher signal-to-noise performance provide significant advantages over previous data sets. CIRS global observations of the mid-infrared spectrum of Jupiter at medium resolution (2.5 cm -1) have been analysed both with a radiance differencing scheme and an optimal estimation retrieval model to retrieve the spatial variation of phosphine and ammonia fractional scale height in the troposphere between 60° S and 60° N at a spatial resolution of 6°. The ammonia fractional scale height appears to be high over the Equatorial Zone (EZ) but low over the North Equatorial Belt (NEB) and South Equatorial Belt (SEB) indicating rapid uplift or strong vertical mixing in the EZ. The abundance of phosphine shows a similar strong latitudinal variation which generally matches that of the ammonia fractional scale height. However while the ammonia fractional scale height distribution is to a first order symmetric in latitude, the phosphine distribution shows a North/South asymmetry at mid latitudes with higher amounts detected at 40° N than 40° S. In addition the data show that while the ammonia fractional scale height at this spatial resolution appears to be low over the Great Red Spot (GRS), indicating reduced vertical mixing above the ˜500 mb level, the abundance of phosphine at deeper levels may be enhanced at the northern edge of the GRS indicating upwelling.

  20. Advances in Nucleophilic Phosphine Catalysis of Alkenes, Allenes, Alkynes, and MBHADs

    PubMed Central

    Fan, Yi Chiao

    2014-01-01

    In nucleophilic phosphine catalysis, tertiary phosphines undergo conjugate additions to activated carbon–carbon multiple bonds to form β-phosphonium enolates, β-phosphonium dienolates, β-phosphonium enoates, and vinyl phosphonium ylides as intermediates. When these reactive zwitterionic species react with nucleophiles and electrophiles, they may generate carbo- and heterocycles with multifarious molecular architectures. This Article describes the reactivities of these phosphonium zwitterions, the applications of phosphine catalysis in the syntheses of biologically active compounds and natural products, and recent developments in the enantioselective phosphine catalysis. PMID:24196409

  1. Advances in Homogeneous Catalysis Using Secondary Phosphine Oxides (SPOs): Pre-ligands for Metal Complexes.

    PubMed

    Achard, Thierry

    2016-01-01

    The secondary phosphine oxides are known to exist in equilibrium between the pentavalent phosphine oxides (SPO) and the trivalent phosphinous acids (PA). This equilibrium can be displaced in favour of the trivalent tautomeric form upon coordination to late transition metals. This tutorial review provides the state of the art of the use of secondary phosphine oxides as pre-ligands in transition metal-catalysed reactions. Using a combination of SPOs and several metals such as Pd, Pt, Ru, Rh and Au, a series of effective and original transformations have been obtained and will be discussed here. PMID:26931212

  2. Experiments in Thermodynamics and Kinetics of Phosphine Substitution in (p-Cymene)RuCl[subscript 2](PR[subscript 3])

    ERIC Educational Resources Information Center

    Ozerov, Oleg V.; Fafard, Claudia M.; Hoffman, Norris W.

    2007-01-01

    This manuscript describes a set of three experiments that investigates the thermodynamic and kinetic aspects of phosphine substitution at a Ru center. In the first experiment, the students synthesize a Ru organometallic complex containing a phosphine ligand. In the second, equilibria for phosphine substitution involving several different

  3. Experiments in Thermodynamics and Kinetics of Phosphine Substitution in (p-Cymene)RuCl[subscript 2](PR[subscript 3])

    ERIC Educational Resources Information Center

    Ozerov, Oleg V.; Fafard, Claudia M.; Hoffman, Norris W.

    2007-01-01

    This manuscript describes a set of three experiments that investigates the thermodynamic and kinetic aspects of phosphine substitution at a Ru center. In the first experiment, the students synthesize a Ru organometallic complex containing a phosphine ligand. In the second, equilibria for phosphine substitution involving several different…

  4. Oxygenated phosphine fumigation for control of Nasonovia ribisnigri (Homoptera: Aphididae) on harvested lettuce

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A laboratory study was conducted to compare phosphine fumigations under the normal and superatmospheric oxygen levels on toxicity against Nasonovia ribisnigri (Mosley) and effects on postharvest quality of romaine and head lettuce. Low temperature phosphine fumigation was effective against the aphi...

  5. Synthesis and reactivity of α-cationic phosphines: the effect of imidazolinium and amidinium substituents.

    PubMed

    Haldón, Estela; Kozma, Ágnes; Tinnermann, Hendrik; Gu, Lianghu; Goddard, Richard; Alcarazo, Manuel

    2016-02-01

    Mono- and dicationic phosphines have been synthesized through the reaction of chloroimidazolinium or chloroamidinium salts with secondary or primary phosphines respectively. The resulting ligands, which depict a significantly reduced donor ability compared with their neutral analogues, have been used to design Pt(ii) and Au(i) complexes that effectively catalyse the hydroarylation of alkynes. PMID:26174600

  6. Parameterization of phosphine ligands reveals mechanistic pathways and predicts reaction outcomes.

    PubMed

    Niemeyer, Zachary L; Milo, Anat; Hickey, David P; Sigman, Matthew S

    2016-06-01

    The mechanistic foundation behind the identity of a phosphine ligand that best promotes a desired reaction outcome is often non-intuitive, and thus has been addressed in numerous experimental and theoretical studies. In this work, multivariate correlations of reaction outcomes using 38 different phosphine ligands were combined with classic potentiometric analyses to study a Suzuki reaction, for which the site selectivity of oxidative addition is highly dependent on the nature of the phosphine. These studies shed light on the generality of hypotheses regarding the structural influence of different classes of phosphine ligands on the reaction mechanism(s), and deliver a methodology that should prove useful in future studies of phosphine ligands. PMID:27219707

  7. Reversible Carbon Dioxide Binding by Simple Lewis Base Adducts with Electron-Rich Phosphines.

    PubMed

    Buß, Florenz; Mehlmann, Paul; Mück-Lichtenfeld, Christian; Bergander, Klaus; Dielmann, Fabian

    2016-02-17

    For the efficient utilization of carbon dioxide as feedstock in chemical synthesis, low-energy-barrier CO2 activation is a valuable tool. We report a metal-free approach to reversible CO2 binding under mild conditions based on simple Lewis base adducts with electron-rich phosphines. Variable-temperature NMR studies and DFT calculations reveal almost thermoneutral CO2 binding with low-energy barriers or stable CO2 adduct formation depending on the phosphines donor ability. The most basic phosphine forms an air-stable CO2 adduct that was used as phosphine transfer agent, providing a convenient access to transition-metal complexes with highly electron-rich phosphine ligands relevant to catalysis. PMID:26824487

  8. Polyimides Containing Pendent Phosphine Oxide Groups for Space Applications

    NASA Technical Reports Server (NTRS)

    Thompson, C. M.; Smith, J. G., Jr.; Watson, K. A.; Connell, J. W.

    2002-01-01

    As part of an ongoing materials development activity to produce high performance polymers that are durable to the space environment, phosphine oxide containing polyimides have been under investigation. A novel dianhydride was prepared from 2,5-dihydroxyphenyldiphenylphosphine oxide in good yield. The dianhydride was reacted with commercially available diamines, and a previously reported diamine was reacted with commercially available dianhydrides to prepare isomeric polyimides. The physical and mechanical properties, particularly thermal and optical properties, of the polymers were determined. One material exhibited a high glass transition temperature, high tensile properties, and low solar absorptivity. The chemistry, physical, and mechanical properties of these resins will be discussed.

  9. Toxicity of phosphine to Carposina niponensis (Lepidoptera: Carposinadae) at low temperature.

    PubMed

    Bo, Liu; Fanhua, Zhang; Yuejin, Wang

    2010-12-01

    Carposina niponensis Matsumura (Lepidoptera: Carposinadae), is widely distributed in pome fruit production areas in China and presents a problem in some export markets because it is considered a quarantine pest by some countries. Methyl bromide is the only fumigant used for fumigation of apples (Malus spp.) for export. However, phosphine is a candidate replacement that can be applied directly at low temperature. Here, laboratory tests showed that tolerance of different stages of C. niponensis to phosphine fumigation at 0 degrees C differed greatly; first-second-instar larvae were the least tolerant stage and the mature fifth instars were the most tolerant stage. In the mature larvae, fumigation tests, with a range of phosphine concentrations from 0.42 to 1.95 mg/liters and exposure periods of 24 h to 14 d at 0 degrees C indicated narcosis when phosphine concentration was > or = 1.67 mg/liter and that a 15.52-8.14-d fumigation period was required to achieve 99% mortality with different phosphine concentrations. The expression of C(0.7)T = k was obtained, which indicated that exposure time was much more important than concentration of phosphine in mortality of mature larvae of C. niponensis. All results suggested that phosphine fumigation at low temperature offers promising control of C. niponensis infestation in pome fruit. PMID:21309217

  10. Line Intensities of the Phosphine Dyad at 10 mu m

    SciTech Connect

    Brown, Linda R.; Sams, Robert L.; Kleiner, Isabelle; Cottaz, C; Sagui, L

    2002-10-01

    Over 1000 measured line intensities of phosphine (PH3) are reported for the 830 to 1310 cm-1 region that contains the two lowest fundamentals in Coriolis interaction. These measurements are fitted to 1.5% for v2 at 992.13 cm-1 for v4 at 1118.31 cm-1, respectively, using five intensity parameters that include three Herman-Wallis type terms. In addition, some 60 intensities of the 2v2-v2 hot band are modeled. The corresponding assignments and line positions of the dyad from previous work [L. Fusina and G. Di Lonardo, J. Mol. Struct. 517-518, 67-78 (2000)] are combined with the present intensity study to provide an improved PH3 database for planetary studies. The total integrated intensity for the dyad is 156.(4) cm-2atm-1 at 296 K.

  11. Biosynthesis of Phosphonic and Phosphinic Acid Natural Products

    PubMed Central

    Metcalf, William W.; van der Donk, Wilfred A.

    2009-01-01

    Natural products containing carbon-phosphorus bonds (phosphonic and phosphinic acids) have found widespread use in medicine and agriculture. Recent years have seen a renewed interest in the biochemistry and biology of these compounds with the cloning of the biosynthetic gene clusters for several family members. This review discusses the commonalities and differences in the molecular logic that lies behind the biosynthesis of these compounds. The current knowledge regarding the metabolic pathways and enzymes involved in the production of a number of natural products, including the approved antibiotic fosfomycin, the widely used herbicide phosphinothricin, and the clinical candidate for treatment of malaria FR900098, is presented. Many of the enzymes involved in the biosynthesis of these compounds catalyze chemically and biologically unprecedented transformations and a wealth of new biochemistry has been revealed through their study. These studies have also suggested new strategies for natural product discovery. PMID:19489722

  12. Reaction paths of phosphine dissociation on silicon (001).

    PubMed

    Warschkow, O; Curson, N J; Schofield, S R; Marks, N A; Wilson, H F; Radny, M W; Smith, P V; Reusch, T C G; McKenzie, D R; Simmons, M Y

    2016-01-01

    Using density functional theory and guided by extensive scanning tunneling microscopy (STM) image data, we formulate a detailed mechanism for the dissociation of phosphine (PH3) molecules on the Si(001) surface at room temperature. We distinguish between a main sequence of dissociation that involves PH2+H, PH+2H, and P+3H as observable intermediates, and a secondary sequence that gives rise to PH+H, P+2H, and isolated phosphorus adatoms. The latter sequence arises because PH2 fragments are surprisingly mobile on Si(001) and can diffuse away from the third hydrogen atom that makes up the PH3 stoichiometry. Our calculated activation energies describe the competition between diffusion and dissociation pathways and hence provide a comprehensive model for the numerous adsorbate species observed in STM experiments. PMID:26747816

  13. Enantioselective Cyclizations of Silyloxyenynes Catalyzed by Cationic Metal Phosphine Complexes

    PubMed Central

    Brazeau, Jean-François; Zhang, Suyan; Colomer, Ignacio; Corkey, Britton K.; Toste, F. Dean

    2012-01-01

    The discovery of complementary methods for enantioselective transition-metal-catalyzed cyclization with silyloxyenynes has been accomplished using chiral phosphine ligands. Under palladium catalysis, 1,6-silyloxyenynes bearing a terminal alkyne led to the desired 5-membered ring with high enantioselectivities (up to 91% ee). As for reactions under cationic gold catalysis, 1,6- and 1,5-silyloxyenynes bearing an internal alkyne furnished the chiral cyclopentane derivatives with excellent enantiomeric excess (up to 94% ee). Modification of the substrate by incorporating an α,β-unsaturation led to the discovery of a tandem cyclization. Remarkably, using silyloxy-1,3-dien-7-ynes under gold catalysis conditions provided the bicyclic derivatives with excellent diastereo- and enantioselectivities (up to >20:1 dr and 99% ee). PMID:22296571

  14. Enantioselective cyclizations of silyloxyenynes catalyzed by cationic metal phosphine complexes.

    PubMed

    Brazeau, Jean-François; Zhang, Suyan; Colomer, Ignacio; Corkey, Britton K; Toste, F Dean

    2012-02-01

    The discovery of complementary methods for enantioselective transition metal-catalyzed cyclization with silyloxyenynes has been accomplished using chiral phosphine ligands. Under palladium catalysis, 1,6-silyloxyenynes bearing a terminal alkyne led to the desired five-membered ring with high enantioselectivities (up to 91% ee). As for reactions under cationic gold catalysis, 1,6- and 1,5-silyloxyenynes bearing an internal alkyne furnished the chiral cyclopentane derivatives with excellent enantiomeric excess (up to 94% ee). Modification of the substrate by incorporating an α,β-unsaturation led to the discovery of a tandem cyclization. Remarkably, using silyloxy-1,3-dien-7-ynes under gold catalysis conditions provided the bicyclic derivatives with excellent diastereo- and enantioselectivities (up to >20:1 dr and 99% ee). PMID:22296571

  15. Reaction paths of phosphine dissociation on silicon (001)

    NASA Astrophysics Data System (ADS)

    Warschkow, O.; Curson, N. J.; Schofield, S. R.; Marks, N. A.; Wilson, H. F.; Radny, M. W.; Smith, P. V.; Reusch, T. C. G.; McKenzie, D. R.; Simmons, M. Y.

    2016-01-01

    Using density functional theory and guided by extensive scanning tunneling microscopy (STM) image data, we formulate a detailed mechanism for the dissociation of phosphine (PH3) molecules on the Si(001) surface at room temperature. We distinguish between a main sequence of dissociation that involves PH2+H, PH+2H, and P+3H as observable intermediates, and a secondary sequence that gives rise to PH+H, P+2H, and isolated phosphorus adatoms. The latter sequence arises because PH2 fragments are surprisingly mobile on Si(001) and can diffuse away from the third hydrogen atom that makes up the PH3 stoichiometry. Our calculated activation energies describe the competition between diffusion and dissociation pathways and hence provide a comprehensive model for the numerous adsorbate species observed in STM experiments.

  16. Effects of phosphine fumigation on survivorship of Epiphyas postvittana (Lepidoptera: Tortricidae) eggs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Light brown apple moth (LBAM), Epiphyas postvittana (Walker), eggs were subjected to regular and oxygenated phosphine fumigations at different temperatures to compare their susceptibilities to the two different fumigation methods and determine effective treatments in laboratory tests. LBAM eggs wer...

  17. Hydroxymethyl phosphine compounds for use as diagnostic and therapeutic pharmaceuticals and method of making same

    DOEpatents

    Katti, Kattesh V.; Karra, Srinivasa Rao; Berning, Douglas E.; Smith, C. Jeffrey; Volkert, Wynn A.; Ketring, Alan R.

    1999-01-01

    A compound and method of making a compound for use as a diagnostic or therapeutic pharmaceutical comprises at least one functionalized hydroxyalkyl phosphine donor group and one or more sulfur or nitrogen donor and a metal combined with the ligand.

  18. Hydroxymethyl phosphine compounds for use as diagnostic and therapeutic pharmaceuticals and method of making same

    DOEpatents

    Katti, Kattesh V.; Karra, Srinivasa Rao; Berning, Douglas E.; Smith, C. Jeffrey; Volkert, Wynn A.; Ketring, Alan R.

    2000-01-01

    A compound and method of making a compound for use as a diagnostic or therapeutic pharmaceutical comprises at least one functionalized hydroxyalkyl phosphine donor group and one or more sulfur or nitrogen donor and a metal combined with the ligand.

  19. Phosphine-free palladium-catalyzed direct bisarylation of pyrroles with aryl iodides on water.

    PubMed

    Cho, Beom Shin; Bae, Hyun Jung; Chung, Young Keun

    2015-05-15

    The Pd-catalyzed bisarylation of pyrroles with aryl iodides on water is described. The reaction proceeds under mild reaction conditions, i.e., relatively low temperature (40 °C) and phosphine-free. PMID:25919427

  20. 40 CFR 721.10135 - Phosphinic acid, P,P-diethyl-, zinc salt (2:1).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Phosphinic acid, P,P-diethyl-, zinc... Specific Chemical Substances § 721.10135 Phosphinic acid, P,P-diethyl-, zinc salt (2:1). (a) Chemical... acid, P,P-diethyl-, zinc salt (2:1) (PMN P-05-11; CAS No. 284685-45-6) is subject to reporting...

  1. 40 CFR 721.10135 - Phosphinic acid, P,P-diethyl-, zinc salt (2:1).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Phosphinic acid, P,P-diethyl-, zinc... Specific Chemical Substances § 721.10135 Phosphinic acid, P,P-diethyl-, zinc salt (2:1). (a) Chemical... acid, P,P-diethyl-, zinc salt (2:1) (PMN P-05-11; CAS No. 284685-45-6) is subject to reporting...

  2. 40 CFR 721.10135 - Phosphinic acid, P,P-diethyl-, zinc salt (2:1).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Phosphinic acid, P,P-diethyl-, zinc... Specific Chemical Substances § 721.10135 Phosphinic acid, P,P-diethyl-, zinc salt (2:1). (a) Chemical... acid, P,P-diethyl-, zinc salt (2:1) (PMN P-05-11; CAS No. 284685-45-6) is subject to reporting...

  3. 40 CFR 721.10135 - Phosphinic acid, P,P-diethyl-, zinc salt (2:1).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Phosphinic acid, P,P-diethyl-, zinc... Specific Chemical Substances § 721.10135 Phosphinic acid, P,P-diethyl-, zinc salt (2:1). (a) Chemical... acid, P,P-diethyl-, zinc salt (2:1) (PMN P-05-11; CAS No. 284685-45-6) is subject to reporting...

  4. 40 CFR 721.10135 - Phosphinic acid, P,P-diethyl-, zinc salt (2:1).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Phosphinic acid, P,P-diethyl-, zinc... Specific Chemical Substances § 721.10135 Phosphinic acid, P,P-diethyl-, zinc salt (2:1). (a) Chemical... acid, P,P-diethyl-, zinc salt (2:1) (PMN P-05-11; CAS No. 284685-45-6) is subject to reporting...

  5. Effect of Low-Temperature Phosphine Fumigation on the Survival of Bactrocera correcta (Diptera: Tephritidae).

    PubMed

    Liu, Tao; Li, Li; Zhang, Fanhua; Gong, Shaorun; Li, Tianxiu; Zhan, Guoping; Wang, Yuejin

    2015-08-01

    This laboratory-based study examined the effects of low-temperature phosphine fumigation on the survival of the eggs and larvae of the guava fruit fly, Bactrocera correcta (Bezzi). Individual flies at different developmental stages, from 6-h-old eggs to third instars, were exposed to 0.92 mg/liter phosphine for 1-7 d at 5°C. We found that 12-h-old eggs and third instars were the most tolerant to phosphine. Increasing phosphine concentrations from 0.46 to 4.56 mg/liter increased mortality in these two stages. However, increased exposure times were required to achieve equal mortality rates in 12-h-old eggs and third instars when phosphine concentrations were ≥4.56 and ≥3.65 mg/liter, respectively. C(n)t = k expression was obtained at 50, 90, and 99% mortality levels, and the toxicity index (n) ranged from 0.43 to 0.77 for the two stages. The synergistic effects of a controlled atmosphere (CA) with elevated CO2 levels were also investigated, and we found that a CO2 concentration between 10% and 15% under CA conditions was optimal for low-temperature phosphine fumigation. PMID:26470302

  6. A novel family of (1-aminoalkyl)(trifluoromethyl)- and -(difluoromethyl)phosphinic acids analogues of ?-amino acids

    PubMed Central

    Pavlenko, Natalia V; Oos, Tatiana I; Gerus, Igor I; Doeller, Uwe; Willms, Lothar

    2014-01-01

    Summary A series of novel (1-aminoalkyl)(trifluoromethyl)- and -(difluoromethyl)phosphinic acids analogues of proteinogenic and nonproteinogenic ?-amino acids were prepared. The synthetic methodology was based on nucleophilic addition of (trifluoromethyl)phosphinic acid or (difluoromethyl)phosphinic acid or its ethyl ester to substrates with C=N or activated C=C double bonds. Analogues of glycine, phenylglycine, alanine, valine, proline, aminomalonic and aspartic acids were thus prepared. Three-component one-pot reactions of (trifluoromethyl)phosphinic acid and dibenzylamine with aldehydes were also tested to prepare the title compounds. PMID:24778725

  7. Performance of phosphine in fumigation of bagged paddy rice in indoor and outdoor stores.

    PubMed

    Rajendran, S; Muralidharan, N

    2001-10-01

    Phosphine fumigation trials were carried out on bag-stacks of paddy rice to study the differences in gas loss rates and concentration-time (Ct) products achieved during the treatment of indoor and outdoor stacks. Stacks (89-132t) were fumigated singly under 250&mgr;m thick polyethylene sheeting, which was sealed with a double layer of sand-snakes to the concrete floor. Phosphine was applied as an aluminium phosphide formulation and the fumigations continued for 7 days. In the first experiment, stacks of paddy rice with moisture contents ranging from 12.2 to 13.7% were held in either indoor or in outdoor storage and subjected to fumigation at the rate of 2, 3 or 4g of phosphine/tonne. The outdoor stacks held relatively low levels of phosphine with Ct products for the indoor stacks of 135, 171 and 294gh/m(3), respectively, whilst the corresponding values for the outdoor stacks were 70, 85 and 166gh/m(3) only. The average gas loss rate was 14.5% per day for the indoor stacks and 29.5% for the outdoor stacks. In the second experiment, old stacks of paddy rice inside a godown, one each with grains at 8.8 and 9.8% moisture content, were fumigated at 3g phosphine/tonne. Release of phosphine was delayed and fumigant sorption was less and therefore higher Ct products of 204 and 216gh/m(3) were achieved. In the stacks built outdoors, the resident infestations of Rhyzopertha dominica, Cryptolestes sp. and Oryzaephilus surinamensis were completely controlled despite lower Ct products. On the other hand, in the stacks of old paddy, R. dominica survived the treatment. Subsequent testing showed that the population had a degree of resistance to phosphine. PMID:11463397

  8. Recent Developments in the Chemistry of N-Heterocyclic Phosphines

    NASA Astrophysics Data System (ADS)

    Gudat, Dietrich

    This chapter gives a survey on five- and six-membered phosphorus-nitrogen heterocyclic compounds whose rings combine a phosphazene (>N-P = N-) or phosphazane (>N-P(X)-N<) unit with an unsaturated C2 or C3 building block. Representatives contain structurally diverse species like aromatic 1,3,2-diazaphosphinines and (benzo)-1,3,2-diazaphospholes, cationic counterparts of subvalent main-group carbene analogues like 1,3,2-diazaphospholenium ions and phosphenium-diketiminates, and neutral heterocycles like 1,3,2-diazaphospholenes featuring unusual structures and reactivities. The exploration of these species developed rapidly in the last two decades in the wake of cutting edge research on multiple bonding and low coordination in the chemistry of heavier main-group elements, and the discovery of stable carbenes. This review summarizes the elaboration of synthetic approaches for different types of N-heterocyclic phosphine derivatives, discusses their characterization by physical and computational methods which furnished a thorough understanding of structure and bonding, and finally highlights accomplishments in the exploration of the chemical properties at the border of classical organic heterocyclic chemistry and molecular inorganic chemistry.

  9. A computed room temperature line list for phosphine

    NASA Astrophysics Data System (ADS)

    Sousa-Silva, Clara; Yurchenko, Sergei N.; Tennyson, Jonathan

    2013-06-01

    An accurate and comprehensive room temperature rotation-vibration transition line list for phosphine (31PH3) is computed using a newly refined potential energy surface and a previously constructed ab initio electric dipole moment surface. Energy levels, Einstein A coefficients and transition intensities are computed using these surfaces and a variational approach to the nuclear motion problem as implemented in the program TROVE. A ro-vibrational spectrum is computed, covering the wavenumber range 0-8000 cm-1. The resulting line list, which is appropriate for temperatures up to 300 K, consists of a total of 137 million transitions between 5.6 million energy levels. Several of the band centres are shifted to better match experimental transition frequencies. The line list is compared to the most recent HITRAN database and other laboratorial sources. Transition wavelengths and intensities are generally found to be in good agreement with the existing experimental data, with particularly close agreement for the rotational spectrum. An analysis of the comparison between the theoretical data created and the existing experimental data is performed, and suggestions for future improvements and assignments to the HITRAN database are made.

  10. Phosphine derivatives of sparfloxacin - Synthesis, structures and in vitro activity

    NASA Astrophysics Data System (ADS)

    Komarnicka, Urszula K.; Starosta, Radosław; Guz-Regner, Katarzyna; Bugla-Płoskońska, Gabriela; Kyzioł, Agnieszka; Jeżowska-Bojczuk, Małgorzata

    2015-09-01

    We synthesized two derivatives of sparfloxacin (HSf): aminomethyl(diphenyl)phosphine (PSf) and its oxide (OPSf). The compounds were characterized by NMR spectroscopy, MS and elemental analysis. In addition, the molecular structures of the compounds were determined using DFT and X-ray (OPSf) analysis. The antibacterial activity of HSf and both derivatives was tested against four reference and fifteen clinical Gram-positive and Gram-negative strains of bacteria (sensitive or resistant to fluoroquinolones). The results showed that the activity of PSf was similar to or higher than the activity of HSf, while OPSf was found significantly less active. The compounds were also tested in vitro toward the following cancer cell lines: mouse colon carcinoma (CT26) and human lung adenocarcinoma (A549). Regardless of the cancer cell line, derivatization of HSf resulted in the gradual increase of cytotoxicity. OPSf exhibited the highest one (4 h - incubation time: IC50(CT26) = 51.0 ± 1.2; IC50(A549) = 74.9 ± 1.4 and 24 h: IC50(CT26) = 109.2 ± 8.8; IC50(A549) = 52.7 ± 9.2).

  11. Phosphine absorption in the 5-micron window of Jupiter

    NASA Technical Reports Server (NTRS)

    Beer, R.; Taylor, F. W.

    1979-01-01

    Since the original suggestion by Gillett et al. (1969) it has generally been assumed that the region of partial transparency near 5 micron in Jupiter's atmosphere (the 5-micron window) is bounded by the nu sub 4 NH3 at 6.1 micron and the nu sub 3 CH4 band at 3.3 micron. New measurements of Jupiter and of laboratory phosphine (PH3) samples show that PH3 is a significant contributor to the continuum opacity in the window and in fact defines its short-wavelength limit. This has important implications for the use of 5-micron observations as a means to probe the deep atmospheric structure of Jupiter. The abundance of PH3 which results from a comparison of Jovian and laboratory spectra is about 3 to 5 cm-am. This is five to eight times less than that found by Larson et al. (1977) in the same spectral region, but is in good agreement with the result of Tokunaga et al. (1979) from 10-micron observations.

  12. Synthesis of p-aminophenyl aryl H-phosphinic acids and esters via cross-coupling reactions: elaboration to phosphinic acid pseudopeptide analogues of pteroyl glutamic acid and related antifolates.

    PubMed

    Yang, Yonghong; Coward, James K

    2007-07-20

    The synthesis of suitably protected p-aminophenyl H-phosphinic acids and esters from the corresponding para-substituted aryl halides has been accomplished via the Pd-catalyzed cross-coupling reaction of anilinium hypophosphite, either in the absence or presence of a tetraalkyl orthosilicate, to provide the free H-phosphinic acid or the corresponding ester, respectively. Subsequent conjugate addition of either a PIII species or phosphorus anion, generated in situ from either the free H-phosphinic acid or ester, to a 2-methylene glutaric acid ester provided the aryl phosphinic acid analogue of p-aminobenzoyl glutamic acid. Alkylation of these suitably protected p-aminophenyl phosphinic acid esters with a 6-(bromomethyl)pteridine or the corresponding (bromomethyl)pyridopyrmidine, followed by hydrolytic removal of protecting groups, provided the target aryl phosphinic acid analogues of folic acid and related antifolates. Alternatively, for the synthesis of the folate or 5-deazafolate analogues on a slightly larger scale, reductive amination with either N2-acetyl or N2-pivaloyl-6-formylpterin or the corresponding formylpyridopyrmidine and the same suitably protected p-aminophenyl phosphinic acid esters, followed by removal of protecting groups, is preferred. In the course of this research, it was observed that the nucleophilicity of both the aniline nitrogen and various PIII species derived from p-aminophenyl phosphinic acid derivatives is significantly reduced compared to that of the unsubstituted counterpart. PMID:17602593

  13. Perfluoroalkyl phosphonic and phosphinic acids as proton conductors for anhydrous proton-exchange membranes.

    PubMed

    Herath, Mahesha B; Creager, Stephen E; Kitaygorodskiy, Alex; DesMarteau, Darryl D

    2010-09-10

    A study of proton-transport rates and mechanisms under anhydrous conditions using a series of acid model compounds, analogous to comb-branch perfluorinated ionomers functionalized with phosphonic, phosphinic, sulfonic, and carboxylic acid protogenic groups, is reported. Model compounds are characterized with respect to proton conductivity, viscosity, proton, and anion (conjugate base) self-diffusion coefficients, and Hammett acidity. The highest conductivities, and also the highest viscosities, are observed for the phosphonic and phosphinic acid model compounds. Arrhenius analysis of conductivity and viscosity for these two acids reveals much lower activation energies for ion transport than for viscous flow. Additionally, the proton self-diffusion coefficients are much higher than the conjugate-base self-diffusion coefficients for these two acids. Taken together, these data suggest that anhydrous proton transport in the phosphonic and phosphinic acid model compounds occurs primarily by a structure-diffusion, hopping-based mechanism rather than a vehicle mechanism. Further analysis of ionic conductivity and ion self-diffusion rates by using the Nernst-Einstein equation reveals that the phosphonic and phosphinic acid model compounds are relatively highly dissociated even under anhydrous conditions. In contrast, sulfonic and carboxylic acid-based systems exhibit relatively low degrees of dissociation under anhydrous conditions. These findings suggest that fluoroalkyl phosphonic and phosphinic acids are good candidates for further development as anhydrous, high-temperature proton conductors. PMID:20602408

  14. Comparative effects of gamma irradiation and phosphine fumigation on the quality of white ginseng

    NASA Astrophysics Data System (ADS)

    Kwon, J.-H. J.-H.; Byun, M.-W. M.-W.; Kim, K.-S. K.-S.; Kang, I.-J. I.-J.

    2000-03-01

    The hygienic, physicochemical, and organoleptic qualities of white ginseng were monitored during 6 months under accelerated conditions (40°C, 90% r.h.) by observing its microbial populations, disinfestation, and some quality attributes following either gamma irradiation at 2.5-10 kGy or commercial phosphine (PH 3) fumigation. In a comparative study, both treatments were found to be effective for disinfecting the stored samples. Phosphine showed no appreciable decontaminating effects on microorganisms contaminated including coliforms, while 5 kGy irradiation was sufficient to control all microorganisms related to the quality of the packed samples. Irradiation at 5 kGy caused negligible changes in physicochemical attributes of the samples, such as ginsenosides, amino acids, fatty acids, and organoleptic properties, whereas phosphine fumigation was found detrimental to sensory flavor ( P<0.01). Quality deterioration occurred in the commercially-packed samples was in the following order: the control, 10 kGy-, phosphine-, and 2.5-5 kGy-treated samples. Accordingly, irradiation at <5 kGy was found to be an effective alternative to phosphine fumigation for white ginseng.

  15. Phosphine fumigation and residues in dry-cured ham in commercial applications.

    PubMed

    Zhao, Y; Abbar, S; Phillips, T W; Schilling, M W

    2015-09-01

    Dry-cured hams often become infested with ham mites (Tyrophagus putrescentiae) during the aging process. Methyl bromide has been used to fumigate dry cured ham plants and is the only available fumigant that is effective at controlling ham mite infestations. However, methyl bromide will eventually be phased out of all industries. This research was designed to determine the efficacy of phosphine fumigation at controlling ham mites and red-legged beetles and any impact of phosphine fumigation on the sensory quality and safety of dry cured hams. Fumigation trials were conducted in simulated ham aging houses and commercial ham aging houses. Mite postembryonic mortality was 99.8% in the simulated aging houses and >99.9% in commercial aging houses three weeks post fumigation. Sensory tests with trained panelists indicated that there were no detectable differences (P > 0.05) between phosphine fumigated and control hams. In addition, residual phosphine concentration was below the legal limit of 0.01 ppm in ham slices that were taken from phosphine fumigated hams. PMID:25951409

  16. Biomolecule conjugation strategy using novel water-soluble phosphine-based chelating agents

    DOEpatents

    Katti, Kattesh V.; Gali, Hariprasad; Volkert, Wynn A.

    2004-08-24

    This invention describes a novel strategy to produce phosphine-functionalized biomolecules (e.g. peptides or proteins) for potential use in the design and development of site-specific radiopharmaceuticals for diagnosis or therapy of specific cancers. Hydrophilic alkyl phosphines, in general, tend to be oxidatively unstable. Therefore, incorporation of such phosphine functionalities on peptide (and other biomolecule) backbones, without oxidizing the P.sup.III centers, is difficult. In this context this discovery reports on a new technology by which phosphines, in the form of bifunctional chelating agents, can be directly incorporated on biomolecular backbones using manual synthetic or solid phase peptide synthesis methodologies. The superior ligating abilities of phosphine ligands, with various diagnostically (e.g. TC-99m) or therapeutically (e.g. Re186/188, Rh-105, Au-199) useful radiometals, coupled with the findings that the resulting complexes demonstrate high in vivo stability makes this approach useful in the development of radiolabeled biomolecules for applications in the design of tumor-specific radiopharmaceuticals.

  17. Bis(aminomethyl)phosphinic Acid, a Highly Promising Scaffold for the Development of Bacterial Urease Inhibitors

    PubMed Central

    2014-01-01

    Inhibitors of bacterial ureases are considered to be promising compounds in the treatment of infections caused by Helicobacter pylori in the gastric tract and/or by urealytic bacteria (e.g., Proteus species) in the urinary tract. A new, extended transition state scaffold, bis(aminomethyl)phosphinic acid, was successfully explored for the construction of effective enzyme inhibitors. A reliable methodology for the synthesis of phosphinate analogues in a three-component Mannich-type reaction was elaborated. The obtained molecules were assayed against ureases purified from Sporosarcina pasteurii and Proteus mirabilis, and aminomethyl(N-n-hexylaminomethyl)phosphinic acid was found to be the most potent inhibitor, with a Ki = 108 nM against the S. pasteurii enzyme. PMID:25699141

  18. Bis(aminomethyl)phosphinic Acid, a Highly Promising Scaffold for the Development of Bacterial Urease Inhibitors.

    PubMed

    Macegoniuk, Katarzyna; Dziełak, Anna; Mucha, Artur; Berlicki, Łukasz

    2015-02-12

    Inhibitors of bacterial ureases are considered to be promising compounds in the treatment of infections caused by Helicobacter pylori in the gastric tract and/or by urealytic bacteria (e.g., Proteus species) in the urinary tract. A new, extended transition state scaffold, bis(aminomethyl)phosphinic acid, was successfully explored for the construction of effective enzyme inhibitors. A reliable methodology for the synthesis of phosphinate analogues in a three-component Mannich-type reaction was elaborated. The obtained molecules were assayed against ureases purified from Sporosarcina pasteurii and Proteus mirabilis, and aminomethyl(N-n-hexylaminomethyl)phosphinic acid was found to be the most potent inhibitor, with a K i = 108 nM against the S. pasteurii enzyme. PMID:25699141

  19. Synthesis and reactivity of a zwitterionic palladium allyl complex supported by a perchlorinated carboranyl phosphine.

    PubMed

    Estrada, Jess; Woen, David H; Tham, Fook S; Miyake, Garret M; Lavallo, Vincent

    2015-06-01

    A zwitterionic palladium complex of a phosphine bearing a perchlorinated carba-closo-dodecaborate anion as a ligand substituent is reported. A single-crystal X-ray diffraction study reveals that, in the solid state, one of the chlorides of the carborane cage occupies a coordination site of the square-planar complex. However, in solution, the P-carborane bond of the ligand is rapidly rotating at temperatures as low as -90 °C, which demonstrates the carborane substituent's weak coordinative ability even though this anion is covalently linked to the phosphine ligand. The complex is thermally stable and catalyzes the vinyl addition polymerization of norbornene. PMID:25965071

  20. Enantioselective total synthesis of (+)-ibophyllidine via an asymmetric phosphine-catalyzed [3 + 2] annulation†

    PubMed Central

    Andrews, Ian P.

    2012-01-01

    In this study we performed the total synthesis of the terpene indole alkaloid (+)-ibophyllidine through a pathway involving asymmetric phosphine catalysis, with our novel l-4-hydroxyproline–derived chiral phosphine mediating the key [3 + 2] annulation. Hydrogenation of the [3 + 2] adduct allowed the rapid formation of the stereochemically dense pyrrolidine ring of (+)-ibophyllidine in excellent yield with exceptionally high levels of both diastereo- and enantioselectivity. We constructed the remainder of the pentacyclic skeleton through an intramolecular alkylation and an intramolecular aza-Morita–Baylis–Hillman reaction. PMID:22798981

  1. Multicomponent reactions of phosphines, enynedioates and benzylidene malononitriles generated highly substituted cyclopentenes through an unexpected phosphine α-addition-δ-evolvement of an anion pathway.

    PubMed

    Chuang, Shih-Ching; Sung, Shih-Ping; Deng, Jie-Cheng; Chiou, Mong-Feng; Hsu, Day-Shin

    2016-02-21

    Multicomponent reactions of phosphines, enynedioates and benzylidene malononitriles provide highly substituted syn-selective cyclopentenes appending the phosphorus ylide moiety in good yield with a diastereoselectivity of up to 100% through resonance-derived 1,5-dipolar species as the key intermediates, via the nucleophilic α(δ')-attack of phosphines toward enynedioates followed by addition to benzylidene malononitriles and 5-exo-dig cyclization. Through computational analyses, the overall reactions for the formation of syn- and anti-diastereomers are both exothermic with 65.6 and 66.3 kcal mol(-1) at the B3LYP-D3/6-31G(d) level of theory and were found to be kinetically controlled, which favours the formation of syn-diastereomers. PMID:26806006

  2. Copper-catalyzed tandem phosphination-decarboxylation-oxidation of alkynyl acids with H-phosphine oxides: a facile synthesis of β-ketophosphine oxides.

    PubMed

    Zhang, Pengbo; Zhang, Liangliang; Gao, Yuzhen; Xu, Jian; Fang, Hua; Tang, Guo; Zhao, Yufen

    2015-05-01

    The general method for the tandem phosphination-decarboxylation-oxidation of alkynyl acids under aerobic conditions has been developed. In the presence of CuSO4·5H2O and TBHP, the reactions provide a novel access to β-ketophosphine oxides in good to excellent yields. This transformation allows the direct formation of a P-C bond and the construction of a keto group in one reaction. PMID:25855268

  3. An Entry to Stable Mixed Phosphine-Osmium-NHC Polyhydrides.

    PubMed

    Buil, María L; Cardo, Juan J F; Esteruelas, Miguel A; Fernández, Israel; Oñate, Enrique

    2016-05-16

    An entry to mixed phosphine-osmium-NHC polyhydride complexes is described, starting from the five-coordinate hydrido-alkylidyne compounds [OsHCl(≡CPh)(IPr)(PR3)]OTf (IPr = 1,3-bis(2,6-disopropylphenyl)imidazolylidene; OTf = CF3SO3; PR3 = P(i)Pr3 (1), PPh3 (2)). The experimental procedure involves the borylation of the Os-C triple bond of 1 and 2 with NaBH4 and the subsequent alcoholysis of the borylation products OsH2Cl(η(2)-H-BCH2Ph)(IPr)(PR3) (PR3 = P(i)Pr3 (3), PPh3 (4)) or OsH2(η(2):η(2):H2BCH2Ph)(IPr)(P(i)Pr3) (5). Stirring of 3 in 2-propanol affords the five coordinate chloride-trihydride OsH3Cl(IPr)(P(i)Pr3)2 (6), which reacts with NaBH4 to give OsH3(κ(2)-H2BH2)(IPr)(P(i)Pr3) (7). This trihydride-tetrahydrideborate derivative and its PPh3 counterpart OsH3(κ(2)-H2BH2)(IPr)(PPh3) (8) can be also obtained in a one-pot procedure, starting from 1 and 2 and using methanol at -60 °C instead of 2-propanol as alcoholysis agent. The bonding situation in 7 and 8, analyzed by DFT calculations using AIM and NBO methods, resembles that found in B2H6 and contrasts with the bonding situation in the bis-σ-borane derivative 5. Stirring of 7 and 8 in 2-propanol leads to the corresponding d(2)-hexahydride derivatives OsH6(IPr)(PR3) (PR3 = P(i)Pr3 (9), PPh3 (10)), which reduce the C≡N triple bond of benzonitrile and promote the subsequent chelate-assisted ortho-CH bond activation of the resulting phenylmethanimine, to form the trihydride compounds OsH3{κ(2)-N,C-(NH═CH-C6H4)}(IPr)(PR3)2 (PR3 = P(i)Pr3 (11), PPh3 (12)), containing a stabilized orthometalated aldimine. PMID:27145380

  4. High temperature partition functions and thermodynamic data for ammonia and phosphine

    NASA Astrophysics Data System (ADS)

    Sousa-Silva, Clara; Hesketh, Nicholas; Yurchenko, Sergei N.; Hill, Christian; Tennyson, Jonathan

    2014-07-01

    The total internal partition function of ammonia (14NH3) and phosphine (31PH3) are calculated as a function of temperature by explicit summation of 153 million (for PH3) and 7.5 million (for NH3) theoretical rotation-vibrational energy levels. High accuracy estimates are obtained for the specific heat capacity, Cp, the Gibbs enthalpy function, gef, the Helmholtz function, hcf, and the entropy, S, of gas phase molecules as a function of temperature. In order to reduce the computational costs associated with the high rotational excitations, only the A-symmetry energy levels are used above a certain threshold of the total angular momentum number J. With this approach levels are summed up to dissociation energy for values of Jmax=45 and 100 for ammonia (Emax=41 051 cm-1) and phosphine (Emax=28 839.7 cm-1), respectively. Estimates of the partition function are converged for all temperatures considered for phosphine and below 3000 K for ammonia. All other thermodynamic properties are converged to at least 2000 K for ammonia and fully converged for phosphine.

  5. Phosphaannulation by palladium-catalyzed carbonylation of C-H bonds of phosphonic and phosphinic acids.

    PubMed

    Shin, Seohyun; Jeong, Yeonseok; Jeon, Woo Hyung; Lee, Phil Ho

    2014-06-01

    An efficient phosphaannulation by Pd-catalyzed carbonylation of C-H bonds of phosphonic and phosphinic acids for the synthesis of oxaphosphorinanone oxides is reported. These compounds are novel phosphorus heterocyclic scaffolds, thus opening a new avenue to sequential C-C/C-O bond formation in one pot. PMID:24856076

  6. Effects of Outside Air Temperature on Movement of Phosphine Gas in Concrete Elevator Bins

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Studies that measured the movement and concentration of phosphine gas in upright concrete bins over time indicated that fumigant movement was dictated by air currents, which in turn, were a function of the difference between the average grain temperature and the average outside air temperature durin...

  7. Fumigation with Phosphine for Postharvest Insect Control on Lettuce, Broccoli, and Strawberries

    Technology Transfer Automated Retrieval System (TEKTRAN)

    U.S. exported lettuce, broccoli, and strawberries often harbor western flower thrips (Frankliniella occidentalis), a quarantined pest in Taiwan, and therefore require quarantine treatment. Pure phosphine fumigation at a low temperature of 2°C was studied as an alternative to methyl bromide to contro...

  8. Oxygenated phosphine fumigation for postharvest control of light brown apple moth on lettuce

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Postharvest treatment for light brown apple moth (LBAM), Epiphyas postvittana (Walker), is needed to safe guard domestic distribution and export of U.S. fresh fruits and vegetables including lettuce as the pest becomes established in California with risk of potential spread. Oxygenated phosphine fu...

  9. LOW TEMPERATURE PHOSPHINE FUMIGATION FOR POSTHARVEST PEST CONTROL ON FRESH VEGETABLES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    U.S. exported lettuce, broccoli, asparagus, and strawberries often harbor western flower thrips (Frankliniella occidentalis), a quarantined pest in Taiwan, and therefore require quarantine treatment. Fumigation with pure phosphine at a low temperature of 2°C was studied to control western flower t...

  10. Hydroxyalkyl phosphine gold complexes for use as diagnostic and therapeutic pharmaceuticals and method of making same

    DOEpatents

    Katti, K.V.; Berning, D.E.; Volkert, W.A.; Ketring, A.R.

    1998-12-01

    A complex and method for making a diagnostic or therapeutic pharmaceutical includes a ligand comprising at least one hydroxyalkyl phosphine donor group bound to a gold atom to form a gold-ligand complex that is stable in aqueous solutions containing oxygen, serum and other body fluids. 20 figs.

  11. Hydroxymethyl phosphine compounds for use as diagnostic and therapeutic pharmaceuticals and method of making same

    DOEpatents

    Katti, K.V.; Karra, S.R.; Berning, D.E.; Smith, C.J.; Volkert, W.A.; Ketring, A.R.

    1999-01-05

    A compound and method of making a compound for use as a diagnostic or therapeutic pharmaceutical comprises at least one functionalized hydroxyalkyl phosphine donor group and one or more sulfur or nitrogen donor and a metal combined with the ligand. 21 figs.

  12. Hydroxyalkyl phosphine gold complexes for use as diagnostic and therapeutic pharmaceuticals and method of making same

    DOEpatents

    Katti, Kattesh V.; Berning, Douglas E.; Volkert, Wynn A.; Ketring, Alan R.

    1998-01-01

    A complex and method for making same for use as a diagnostic or therapeutic pharmaceutical includes a ligand comprising at least one hydroxyalkyl phosphine donor group bound to a gold atom to form a gold-ligand complex that is stable in aqueous solutions containing oxygen, serum and other body fluids.

  13. Phosphinate stabilised ZnO and Cu colloidal nanocatalysts for CO2 hydrogenation to methanol.

    PubMed

    Brown, N J; Weiner, J; Hellgardt, K; Shaffer, M S P; Williams, C K

    2013-12-01

    Colloidal solutions of ZnO-Cu nanoparticles can be used as catalysts for the reduction of carbon dioxide with hydrogen. The use of phosphinate ligands for the synthesis of the nanoparticles from organometallic precursors improves the reductive stability and catalytic activity of the system. PMID:24141490

  14. Nickel phosphine catalysts with pendant amines for electrocatalytic oxidation of alcohols.

    PubMed

    Weiss, Charles J; Wiedner, Eric S; Roberts, John A S; Appel, Aaron M

    2015-04-11

    Nickel phosphine complexes with pendant amines have been found to be electrocatalysts for the oxidation of primary and secondary alcohols, with turnover frequencies as high as 3.3 s(-1). These complexes are the first electrocatalysts for alcohol oxidation based on non-precious metals, which will be critical for use in fuel cells. PMID:25753760

  15. Penguins significantly increased phosphine formation and phosphorus contribution in maritime Antarctic soils

    PubMed Central

    Zhu, Renbin; Wang, Qing; Ding, Wei; Wang, Can; Hou, Lijun; Ma, Dawei

    2014-01-01

    Most studies on phosphorus cycle in the natural environment focused on phosphates, with limited data available for the reduced phosphine (PH3). In this paper, matrix-bound phosphine (MBP), gaseous phosphine fluxes and phosphorus fractions in the soils were investigated from a penguin colony, a seal colony and the adjacent animal-lacking tundra and background sites. The MBP levels (mean 200.3 ng kg−1) in penguin colony soils were much higher than those in seal colony soils, animal-lacking tundra soils and the background soils. Field PH3 flux observation and laboratory incubation experiments confirmed that penguin colony soils produced much higher PH3 emissions than seal colony soils and animal-lacking tundra soils. Overall high MBP levels and PH3 emissions were modulated by soil biogeochemical processes associated with penguin activities: sufficient supply of the nutrients phosphorus, nitrogen, and organic carbon from penguin guano, high soil bacterial abundance and phosphatase activity. It was proposed that organic or inorganic phosphorus compounds from penguin guano or seal excreta could be reduced to PH3 in the Antarctic soils through the bacterial activity. Our results indicated that penguin activity significantly increased soil phosphine formation and phosphorus contribution, thus played an important role in phosphorus cycle in terrestrial ecosystems of maritime Antarctica. PMID:25394572

  16. Factors Affecting Energy Barriers for Pyramidal Inversion in Amines and Phosphines: A Computational Chemistry Lab Exercise

    ERIC Educational Resources Information Center

    Montgomery, Craig D.

    2013-01-01

    An undergraduate exercise in computational chemistry that investigates the energy barrier for pyramidal inversion of amines and phosphines is presented. Semiempirical calculations (PM3) of the ground-state and transition-state energies for NR[superscript 1]R[superscript 2]R[superscript 3] and PR[superscript 1]R[superscript 2]R[superscript 3] allow…

  17. Temporary Protection of H-Phosphinic Acids as a Synthetic Strategy.

    PubMed

    Coudray, Laëtitia; Montchamp, Jean-Luc

    2009-09-01

    H-Phosphinates obtained through various methodologies are protected directly via reaction with triethyl orthoacetate. The resulting products can be manipulated easily, and various synthetic reactions are presented. For example, application to the synthesis of aspartate transcarbamoylase (ATCase) or kynureninase inhibitors are illustrated. Other reactions, such as Sharpless' asymmetric dihydroxylation, or Grubbs' olefin cross-metathesis are also demonstrated. PMID:24273443

  18. Temporary Protection of H-Phosphinic Acids as a Synthetic Strategy

    PubMed Central

    Coudray, Laëtitia

    2013-01-01

    H-Phosphinates obtained through various methodologies are protected directly via reaction with triethyl orthoacetate. The resulting products can be manipulated easily, and various synthetic reactions are presented. For example, application to the synthesis of aspartate transcarbamoylase (ATCase) or kynureninase inhibitors are illustrated. Other reactions, such as Sharpless’ asymmetric dihydroxylation, or Grubbs’ olefin cross-metathesis are also demonstrated. PMID:24273443

  19. Hessian fly mortality by phosphine-carbon dioxide fumigation and postharvest drying

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hessian fly, Mayetiola destructor (Say), puparia, the stage of regulatory concern that may be found in weeds contaminating exported hay, may be controlled with a phosphine and carbon dioxide gas mixture dispensed from cylinders at a minimum dose of 750 ppm, temperature of 20°C (68°F) or higher, and ...

  20. Factors Affecting Energy Barriers for Pyramidal Inversion in Amines and Phosphines: A Computational Chemistry Lab Exercise

    ERIC Educational Resources Information Center

    Montgomery, Craig D.

    2013-01-01

    An undergraduate exercise in computational chemistry that investigates the energy barrier for pyramidal inversion of amines and phosphines is presented. Semiempirical calculations (PM3) of the ground-state and transition-state energies for NR[superscript 1]R[superscript 2]R[superscript 3] and PR[superscript 1]R[superscript 2]R[superscript 3] allow

  1. Coinage metal coordination chemistry of stable primary, secondary and tertiary ferrocenylethyl-based phosphines.

    PubMed

    Azizpoor Fard, M; Rabiee Kenaree, A; Boyle, P D; Ragogna, P J; Gilroy, J B; Corrigan, J F

    2016-02-21

    Ferrocene-based phosphines constitute an important auxiliary ligand in inorganic chemistry. Utilizing the (ferrocenylethyl)phosphines (FcCH2CH2)3-nHnP (Fc = ferrocenyl; n = 2, 1; n = 1, 2; n = 0, 3) the synthesis of a series of coordination complexes [(FcCH2CH2)3-nHnPCuCl]4 (n = 2, 1-CuCl; n = 0, 3-CuCl), [(FcCH2CH2)2HPCuCl] (2-CuCl), {[(FcCH2CH2)H2P]2AgCl}2 (1-AgCl), [(FcCH2CH2)2HPAgCl] (2-AgCl), [(FcCH2CH2)3PAgCl]4 (3-AgCl), [(FcCH2CH2)3PM(OAc)]4 (M = Cu, 3-CuOAc M = Ag, 3-AgOAc), [(FcCH2CH2)3-nHnPAuCl] (n = 1, 2-AuCl; n = 0, 3-AuCl), via the reaction between the free phosphine and MX (M = Cu, Ag and Au; X = Cl, OAc), is described. The reaction between the respective phosphine with a suspension of metal-chloride or -acetate in a 1 : 1 ratio in THF at ambient temperature affords coordinated phosphine-coinage metal complexes. Varying structural motifs are observed in the solid state, as determined via single crystal X-ray analysis of 1-CuCl, 3-CuCl, 1-AgCl, 3-AgCl, 3-CuOAc, 3-AgOAc, 2-AuCl and 3-AuCl. Complexes 1-CuCl and 3-CuCl are tetrameric Cu(i) cubane-like structures with a Cu4Cl4 core, whereas silver complexes with primary and tertiary phosphine reveal two different structural types. The structure of 1-AgCl, unlike the rest, displays the coordination of two phosphines to each silver atom and shows a quadrangle defined by two Ag and two Cl atoms. In contrast, 3-AgCl is distorted from a cubane structure via elongation of one of the ClAg distances. 3-CuOAc and 3-AgOAc are isostructural with step-like cores, while complexes 2-AuCl and 3-AuCl reveal a linear geometry of a phosphine gold(i) chloride devoid of any aurophilic interactions. All of the complexes were characterized in solution by multinuclear (1)H, (13)C{(1)H} and (31)P NMR spectroscopic techniques; the redox chemistry of the series of complexes was examined using cyclic voltammetry. This class of complexes has been found to exhibit one reversible Fe(ii)/Fe(iii) oxidation couple, suggesting the absence of electronic communication between the ferrocenyl units on individual phosphine ligands as well as between different phosphines on the polymetallic cores. PMID:26792103

  2. Interaction of tertiary phosphines with lignin-type, alpha,beta-unsaturated aldehydes in water.

    PubMed

    Moiseev, Dmitry V; Patrick, Brian O; James, Brian R; Hu, Thomas Q

    2007-10-29

    To learn more about the bleaching action of pulps by (hydroxymethyl)phosphines, lignin chromophores, such as the alpha,beta-unsaturated aromatic aldehydes, sinapaldehyde, coniferylaldehyde, and coumaraldehyde, were reacted with the tertiary phosphines R2R'P [R = R' = Me, Et, (CH2)3OH, iPr, cyclo-C6H11, (CH2)2CN; R = Me or Et, R' = Ph; R = Ph, R' = Me, m-NaSO3-C6H4] in water at room temperature under argon. In all cases, initial nucleophilic attack of the phosphine occurs at the activated C=C bond to form a zwitterionic monophosphonium species. With the phosphines PR3 [R = Me, Et, (CH2)3OH] and with R2R'P (R = Me or Et, R' = Ph), the zwitterion undergoes self-condensation to give a bisphosphonium zwitterion that can react with aqueous HCl to form the corresponding dichloride salts (as a mixture of R,R- and S,S-enantiomers); X-ray structures are presented for the bisphosphonium chlorides synthesized from the Et3P and Me3P reactions with sinapaldehyde. With the more bulky phosphines, iPr3P, MePPh2, (cyclo-C6H11)3P, and Na[Ph2P(m-SO3-C6H4)], only an equilibrium of the monophosphonium zwitterion with the reactant aldehyde is observed. The weakly nucleophilic [NC(CH2)2]3P does not react with sinapaldehyde. An analysis of some exceptional 1H NMR data within the prochiral phosphorus centers of the bisphosphonium chlorides is also presented. PMID:17914858

  3. Synthesis and coordination chemistry of tridentate (PNN) amine enamido phosphine ligands with ruthenium.

    PubMed

    Wambach, T C; Lenczyk, C; Patrick, B O; Fryzuk, M D

    2016-04-01

    Tridentate amine-imine-phosphine ligands, R2PC5H7NC2H4NEt2 [(R)PNN(H)], where R = Pr(i) or Bu(t) are synthesized using a straightforward protocol of condensation, deprotonation, and addition of a chlorodialkylphosphine. Multinuclear NMR spectroscopy shows the ligands exist exclusively in the enamine tautomeric form in solution. Treating these ligands with RuHCl(PPr(i)3)2(CO) forms the desired coordination compounds, RuHCl[(R)PNN(H)](CO), where the imine tautomeric form of the ligands coordinates to ruthenium. Deuterium labelling experiments show Ru-H/N-D scrambling occurs during ligand coordination. Treating the RuHCl[(R)PNN(H)](CO) precursors with potassium tert-butoxide allows for the synthesis of two new ruthenium enamido-phosphine complexes, RuH[(R)PNN](CO), which were fully characterized. The structure of one of the derivatives was confirmed by X-ray crystallography (R = Pr(i)). The reactivity of the enamido-phosphine complexes with H2 and benzyl alcohol is also reported. For the enamido phosphine complex where R = Pr(i), the reaction with H2 is reversible and forms (RuH(CO)[(Pri)PNN(H)])2(μ-H)2, a hydride-bridged dimer that results from cooperative activation of H2. The reactivity of both amine-enamido-phosphine ruthenium compounds with benzyl alcohol establishes that the complexes are catalyst precursors for acceptorless dehydrogenation (AD), although the turnover frequencies measured using both catalyst precursors are modest. PMID:26916542

  4. Phosphines are ribonucleotide reductase reductants that act via C-terminal cysteines similar to thioredoxins and glutaredoxins

    PubMed Central

    Domkin, Vladimir; Chabes, Andrei

    2014-01-01

    Ribonucleotide reductases (RNRs) catalyze the formation of 2′-deoxyribonucleotides. Each polypeptide of the large subunit of eukaryotic RNRs contains two redox-active cysteine pairs, one in the active site and the other at the C-terminus. In each catalytic cycle, the active-site disulfide is reduced by the C-terminal cysteine pair, which in turn is reduced by thioredoxins or glutaredoxins. Dithiols such as DTT are used in RNR studies instead of the thioredoxin or glutaredoxin systems. DTT can directly reduce the disulfide in the active site and does not require the C-terminal cysteines for RNR activity. Here we demonstrate that the phosphines tris(2-carboxyethyl)phosphine (TCEP) and tris(3-hydroxypropyl)phosphine (THP) are efficient non-thiol RNR reductants, but in contrast to the dithiols DTT, bis(2-mercaptoethyl)sulfone (BMS), and (S)-(1,4-dithiobutyl)-2-amine (DTBA) they act specifically via the C-terminal disulfide in a manner similar to thioredoxin and glutaredoxin. The simultaneous use of phosphines and dithiols results in ~3-fold higher activity compared to what is achieved when either type of reductant is used alone. This surprising effect can be explained by the concerted action of dithiols on the active-site cysteines and phosphines on the C-terminal cysteines. As non-thiol and non-protein reductants, phosphines can be used to differentiate between the redox-active cysteine pairs in RNRs. PMID:24986213

  5. Diphosphine is an intermediate in the photolysis of phosphine to phosphorus and hydrogen. [Jupiter atmospheric chemistry

    NASA Technical Reports Server (NTRS)

    Ferris, J. P.; Benson, R.

    1980-01-01

    The photolysis of phosphine to red phosphorus (P4) and hydrogen is investigated in light of the potential significance of the reaction in the atmospheric chemistry of Jupiter. It is reported that the photolysis of PH3 at room temperature by a 206.2-nm light source gave rise to a product identified by its UV and IR spectra and gas chromatographic retention time as P2H4, the yield of which is found to increase to a maximum and then decrease to 20% of the maximum value with illumination time. A mechanism for phosphine photolysis including diphosphine formation as an intermediate step is proposed, and it is concluded that P2H4 is a likely constituent of the atmospheres of the Jovian planets.

  6. Rate constant for the reaction of atomic oxygen with phosphine at 298 K

    NASA Technical Reports Server (NTRS)

    Stief, L. J.; Payne, W. A.; Nava, D. F.

    1987-01-01

    The rate constant for the reaction of atomic oxygen with phosphine has been measured at 298 K using flash photolysis combined with time-resolved detection of O(3P) via resonance fluorescence. Atomic oxygen was produced by flash photolysis of N2O or NO highly diluted in argon. The results were shown to be independent of (PH3), (O), total pressure and the source of O(3P). The mean value of all the experiments is k1 = (3.6 + or -0.8) x 10 to the -11th cu cm/s (1 sigma). Two previous measurements of k1 differed by more than an order of magnitude, and the results support the higher value obtained in a discharge flow-mass spectrometry study. A comparison with rate data for other atomic and free radical reactions with phosphine is presented, and the role of these reactions in the aeronomy or photochemistry of Jupiter and Saturn is briefly considered.

  7. Hydrogen release from systems containing phosphine, borane, alane and galane: A mechanistic study

    NASA Astrophysics Data System (ADS)

    Nguyen, Vinh Son; Majumdar, D.; Leszczynski, Jerzy; Nguyen, Minh Tho

    2013-10-01

    The H2 release mechanism from phosphine borane and phosphine alane was investigated using quantum chemical methods (MP2/aug-cc-pVTZ geometry optimization and coupled-cluster energies were obtained through complete basis set extrapolation, CCSD(T)/CBS). The effect of catalysts borane, alane and galane on the processes was also explored. As the energy barriers for the release of H2 from BH3PH3 and AlH3PH3 are much higher than the B-P and Al-P bond energies, the presence of inherent catalysts can reduce substantially such energy barriers (using BH3 for BH3PH3, while AlH3 and GaH3 for AlH3PH3), and these systems could be useful as probable hydrogen source.

  8. Synthesis and Lanthanide Coordination Chemistry of Phosphine Oxide Decorated Dibenzothiophene and Dibenzothiophene Sulfone Platforms

    SciTech Connect

    Rosario-Amorin, Daniel; Ouizem, Sabrina; Dickie, D. A.; Paine, Robert T.; Cramer, Roger E.; Hay, Benjamin; Podair, Julien; Delmau, Laetitia Helene

    2014-01-01

    Syntheses for new ligands based upon dibenzothiophene and dibenzothiophene sulfone platforms, decorated with phosphine oxide and methylphosphine oxide donor groups, are described. Coordination chem. of 4, 6- bis(diphenylphosphinoylmethyl) dibenzothiophene (8) , 4, 6- bis(diphenylphosphinoylmethyl) dibenzothiophene- 5, 5- dioxide (9) and 4, 6- bis(diphenylphosphinoyl) dibenzothiophene- 5, 5- dioxide (10) with lanthanide nitrates, Ln(NO3) 3 (H2O) n is outlined, and crystal structure detns. reveal a range of chelation interactions on Ln(III) ions. The HNO3 dependence of the solvent extn. performance of 9 and 10 in 1, 2- dichloroethane for Eu(III) and Am(III) is described and compared against the extn. behavior of related dibenzofuran ligands (2, 3; R = Ph) and n- octyl(phenyl) - N, N- diisobutylcarbamoylmethyl phosphine oxide (4) measured under identical conditions.

  9. Synthesis and proton NMR studies of the electronic structure of ferric phosphine porphyrin complexes

    SciTech Connect

    Simonneaux, G.; Sodano, P.

    1988-11-02

    The preparation and spectral properties of low-spin ferric phosphine complexes of a series of synthetic and natural porphyrins have been reported. The proton NMR spectra of Fe(TPP)(PMe/sub 3/)/sub 2/ClO/sub 4/ and Fe(TPP)(PMe/sub 3/)(1-Melm)ClO/sub 4/ have been analyzed. The axial ligand hyperfine shifts have been separated into their dipolar and contact contributions by using both the dominant dipolar shifts for certain porphyrin positions and the magnetic anisotropy data derived from low-temperature ESR spectra. The contact shifts are shown to arise primarily from iron ..-->.. phosphine ..pi..* charge transfer. The trimethylphosphine H peak is shown to shift characteristically upfield on going from (Fe(TPP)PMe/sub 32/)/sup +/ to (Fe(TPP)(PMe/sub 3/)(1-MeIm))/sup +/, confirming that this resonance may serve as a new probe for hemoproteins. 25 references, 2 figures, 3 tables.

  10. Synthesis and Structural Studies of Calcium and Magnesium Phosphinate and Phosphonate Compounds

    NASA Astrophysics Data System (ADS)

    Bampoh, Victoria Naa Kwale

    The work presented herein describes synthetic methodologies leading to the design of a wide array of magnesium and calcium based phosphinate and phosphonates with possible applications as bone scaffolding materials or additives to bone cements. The challenge to the chemistry of the alkaline earth phosphonate target compounds includes poor solubility of compounds, and poorly understood details on the control of the metal's coordination environment. Hence, less is known on phosphonate based alkaline earth metal organic frameworks as compared to transition metal phosphonates. Factors governing the challenges in obtaining crystalline, well-defined magnesium and calcium solids lie in the large metal diameters, the absence of energetically available d-orbitals to direct metal geometry, as well as the overall weakness of the metal-ligand bonds. A significant part of this project was concerned with the development of suitable reaction conditions to obtain X-ray quality crystals of the reaction products to allow for structural elucidation of the novel compounds. Various methodologies to aid in crystal growth including hydrothermal methods and gel crystallization were employed. We have used phosphinate and phosphonate ligands with different number of phosphorus oxygen atoms as well as diphosphonates with different linker lengths to determine their effects on the overall structural features. An interesting correlation is observed between the dimensionality of products and the increasing number of donor oxygen atoms in the ligands as we progress from phosphinic acid to the phosphorous acids. As an example, monophosphinate ligand only yielded one-dimensional compounds, whereas the phosphonates crystallize as one and two-dimensional compounds, and the di- and triphosphonate based compounds display two or three-dimensional geometries. This thesis provides a selection of calcium and magnesium compounds with one-dimensional geometry, as represented in a calcium phosphinate to novel two-dimensional sheets of magnesium and pillared calcium phosphonates. The preparation of these novel compounds has led to the establishment of synthetic protocols that allow for the direct preparation of compounds with defined structural features.

  11. Enantioselective Synthesis of Isoquinolines: Merging Chiral-Phosphine and Gold Catalysis.

    PubMed

    Gao, Yu-Ning; Shi, Feng-Chen; Xu, Qin; Shi, Min

    2016-05-10

    The highly enantioselective synthesis of dihydroisoquinoline derivatives from aromatic sulfonated imines tethered with an alkyne moiety, through a one-pot asymmetric relay catalysis of chiral-phosphine and gold catalysts, is reported. Enantiomerically enriched dihydroisoquinoline derivatives were afforded in good yields and good-to-excellent ee values under mild conditions, based on the asymmetric aza-Morita-Baylis-Hillman reaction. Dihydroisoquinoline derivatives containing two chiral centers were also synthesized through further transformations. PMID:26990120

  12. Small Molecule Activation by Intermolecular Zr(IV)-Phosphine Frustrated Lewis Pairs.

    PubMed

    Metters, Owen J; Forrest, Sebastian J K; Sparkes, Hazel A; Manners, Ian; Wass, Duncan F

    2016-02-17

    We report intermolecular transition metal frustrated Lewis pairs (FLPs) based on zirconocene aryloxide and phosphine moieties that exhibit a broad range of small molecule activation chemistry that has previously been the preserve of only intramolecular pairs. Reactions with D2, CO2, THF, and PhCCH are reported. By contrast with previous intramolecular examples, these systems allow facile access to a variety of steric and electronic characteristics at the Lewis acidic and Lewis basic components, with the three-step syntheses of 10 new intermolecular transition metal FLPs being reported. Systematic variation to the phosphine Lewis base is used to unravel steric considerations, with the surprising conclusion that phosphines with relatively small Tolman steric parameters not only give highly reactive FLPs but are often seen to have the highest selectivity for the desired product. DOSY NMR spectroscopic studies on these systems reveal for the first time the nature of the Lewis acid/Lewis base interactions in transition metal FLPs of this type. PMID:26788963

  13. Ruthenium complexes of P-stereogenic phosphines with a heterocyclic substituent.

    PubMed

    Clavero, Pau; Grabulosa, Arnald; Rocamora, Mercè; Muller, Guillermo; Font-Bardia, Mercè

    2016-05-28

    The synthesis via phosphine-boranes of 13 new optically pure P-stereogenic diarylphosphines P(Het)PhR (Het = 4-dibenzofuranyl (DBF), 4-dibenzothiophenyl (DBT), 4-dibenzothiophenyl-S,S-dioxide (DBTO2) and 1-thianthrenyl (TA); R = OMe, Me, i-Pr, Fc (ferrocenyl)) following the Jugé-Stephan method is described. The ligands were designed with the aim of having a heteroatom in a position capable of interacting with a metal upon coordination. The ligands and their precursors have been fully characterised, including the determination of two crystal structures of phosphine-boranes. Ru neutral complexes of the type [RuCl2(η(6)-arene)(κP-P)] (arene = p-cymene and methyl benzoate) have been prepared and characterised, including three crystal structure determinations. Treatment of solutions of the complexes with TlPF6 allowed the preparation of well-defined cationic complexes [RuCl(η(6)-arene)(κ(2)P,S-P)]PF6 for DBT- and TA-based phosphines. The complexes possess a stereogenic Ru atom and in most of the cases they are present as a single isomer in solution. All the Ru complexes have been used in the asymmetric transfer hydrogenation of acetophenone in refluxing 2-propanol, with good activities and up to 70% ee. PMID:27117834

  14. Phosphine-free synthesis of Ag-In-Se alloy nanocrystals with visible emissions.

    PubMed

    Yao, Dong; Liu, Huiwen; Liu, Yi; Dong, Chunwei; Zhang, Kai; Sheng, Yu; Cui, Jianli; Zhang, Hao; Yang, Bai

    2015-11-28

    As promising heavy metal-free emitting materials, Ag-In-Se nanocrystals (NCs) are conventionally synthesized using organic phosphine agents and exhibit near-infrared emissions. In this work, we demonstrate a rapid phosphine-free approach for synthesizing Ag-In-Se alloy NCs with the emissions tunable to the visible region on the basis of the phosphine-free dissolution of Se powder. At room temperature, Se powder is reduced by dodecanethiol and dissolved in oleylamine to produce a Se precursor. The resultant Se precursor is highly active, which permits rapid synthesis at a relatively low temperature, such as at 90 °C for 150 s. By optimizing the size, structure, and composition, the photoluminescence quantum yield of the as-synthesized Ag-In-Se NCs is enhanced to up to 10%. The growth of the Ag-In-Se NCs involves composition and phase transition, which strongly depend on the reaction temperature. The Ag2Se nuclei form first, and the Ag-In-Se NCs are produced by doping In(3+) into the preformed Ag2Se nuclei. Tetragonal phase Ag-In-Se is obtained below 170 °C, while the orthorhombic phase appears over 190 °C. The potential of Ag-In-Se NCs as red emitting phosphors for lighting-emitting diodes is further demonstrated. PMID:26489872

  15. Designing Organic Phosphine Oxide Host Materials Using Heteroaromatic Building Blocks: Inductive Effects on Electroluminescence

    SciTech Connect

    Sapochak, Linda S.; Padmaperuma, Asanga B.; Vecchi, Paul A.; Cai, Xiuyu; Burrows, Paul E.

    2007-11-19

    Phosphine oxide substitution of small molecules with high triplet exciton energies allows development of vacuum sublimable, electron transporting host materials for blue OLEDs. Heteroaromatic building blocks (carbazole, dibenzofuran and dibenzothiophene) with ET ~ 3 eV were incorporated into phosphine oxide (PO) structures. External quantum efficiencies (EQEs) at lighting brightness (i.e., 800 cd/m2) reached as high as 9.8% at 5.2V for OLEDs using the heteroaromatic PO hosts doped with the sky blue phosphor, iridium(III)bis(4,6-(di-fluorophenyl)-pyridinato-N,C2’) picolinate (FIrpic). Comparing device properties at a similar current density (i.e., J = 13 mA/cm2) showed the dibenzothiophene-bridged PO compound exhibits the highest EQEs and lowest operating voltages at all phosphor dopant levels. These results are explained with respect to the effects of the inductive phosphine oxide substituents on electrochemical, photophysical and electroluminescence properties of the substituted heteroaromatic building blocks.

  16. Designing organic phosphine oxide host materials using heteroarmatic building blocks: inductive effects on electroluminescence

    NASA Astrophysics Data System (ADS)

    Sapochak, Linda S.; Padmaperuma, Asanga B.; Vecchi, Paul A.; Cai, Xiuyu; Burrows, Paul E.

    2007-09-01

    Phosphine oxide substitution of small molecules with high triplet exciton energies allows development of vacuum sublimable, electron transporting host materials for blue OLEDs. Heteroaromatic building blocks (carbazole, dibenzofuran and dibenzothiophene) with E T ~ 3 eV were incorporated into phosphine oxide (PO) structures. External quantum efficiencies (EQEs) at lighting brightness (i.e., 800 cd/m2) reached as high as 9.8% at 5.2V for OLEDs using the heteroaromatic PO hosts doped with the sky blue phosphor, iridium(III)bis(4,6-(di-fluorophenyl)-pyridinato-N,C 2,) picolinate (FIrpic). Comparing device properties at a similar current density (i.e., J = 13 mA/cm2) showed the dibenzothiophene-bridged PO compound exhibits the highest EQEs and lowest operating voltages at all phosphor dopant levels. These results are explained with respect to the effects of the inductive phosphine oxide substituents on electrochemical, photophysical and electroluminescence properties of the substituted heteroaromatic building blocks.

  17. Decomposition Products of Phosphine Under Pressure: PH2 Stable and Superconducting?

    PubMed

    Shamp, Andrew; Terpstra, Tyson; Bi, Tiange; Falls, Zackary; Avery, Patrick; Zurek, Eva

    2016-02-17

    Evolutionary algorithms (EAs) coupled with density functional theory (DFT) calculations have been used to predict the most stable hydrides of phosphorus (PHn, n = 1-6) at 100, 150, and 200 GPa. At these pressures phosphine is unstable with respect to decomposition into the elemental phases, as well as PH2 and H2. Three metallic PH2 phases were found to be dynamically stable and superconducting between 100 and 200 GPa. One of these contains five formula units in the primitive cell and has C2/m symmetry (5FU-C2/m). It comprises 1D periodic PH3-PH-PH2-PH-PH3 oligomers. Two structurally related phases consisting of phosphorus atoms that are octahedrally coordinated by four phosphorus atoms in the equatorial positions and two hydrogen atoms in the axial positions (I4/mmm and 2FU-C2/m) were the most stable phases between ∼160-200 GPa. Their superconducting critical temperatures (Tc) were computed as 70 and 76 K, respectively, via the Allen-Dynes modified McMillan formula and using a value of 0.1 for the Coulomb pseudopotential, μ*. Our results suggest that the superconductivity recently observed by Drozdov, Eremets, and Troyan when phosphine was subject to pressures of 207 GPa in a diamond anvil cell may result from these, and other, decomposition products of phosphine. PMID:26777416

  18. Evaluation of phosphine genotoxicity at occupational levels of exposure in New South Wales, Australia.

    PubMed Central

    Barbosa, A; Bonin, A M

    1994-01-01

    Phosphine has been claimed to cause chromosomal damage at exposures close to the current time weighted average exposure standard of 0.3 ppm (0.4 mg/m3). The current study involved 31 phosphine fumigators and 21 controls during the high fumigation season. All were volunteers and were evaluated for genotoxicity variables, including micronuclei in peripheral blood lymphocytes and urine mutagenicity. In parallel, all fumigators and 17 controls were evaluated for full haematology, multiple biochemical analysis, whole blood organochlorines, and whole blood and serum cholinesterase activity. The results for micronuclei showed no significant differences between fumigators and controls, but detected a strong association between age and increased frequency of micronuclei. Measurement of urine mutagenicity did not show any significant difference between fumigators and controls, but did show increased excretion of mutagens in smokers. All haematological and biochemical variables were within normal ranges, except for some non-specific changes in biochemistry. At monitored occupational exposures of < 2.4 ppm/h our results show no association between phosphine exposure and genotoxic or toxicological effects in fumigators. PMID:8000496

  19. Synthesis of phosphine and antibody-azide probes for in vivo Staudinger ligation in a pretargeted imaging and therapy approach.

    PubMed

    Vugts, Danielle J; Vervoort, Annelies; Stigter-van Walsum, Marijke; Visser, Gerard W M; Robillard, Marc S; Versteegen, Ron M; Vulders, Roland C M; Herscheid, J Koos D M; van Dongen, Guus A M S

    2011-10-19

    The application of intact monoclonal antibodies (mAbs) as targeting agents in nuclear imaging and radioimmunotherapy is hampered by the slow pharmacokinetics of these molecules. Pretargeting with mAbs could be beneficial to reduce the radiation burden to the patient, while using the excellent targeting capacity of the mAbs. In this study, we evaluated the applicability of the Staudinger ligation as pretargeting strategy using an antibody-azide conjugate as tumor-targeting molecule in combination with a small phosphine-containing imaging/therapeutic probe. Up to 8 triazide molecules were attached to the antibody without seriously affecting its immunoreactivity, pharmacokinetics, and tumor uptake in tumor bearing nude mice. In addition, two (89)Zr- and (67/68)Ga-labeled desferrioxamine (DFO)-phosphines, a (177)Lu-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA)-phosphine and a (123)I-cubyl phosphine probe were synthesized and characterized for their pharmacokinetic behavior in nude mice. With respect to the phosphine probes, blood levels at 30 min after injection were <5% injected dose per gram tissue, indicating rapid blood clearance. In vitro Staudinger ligation of 3.33 μM antibody-azide conjugate with 1 equiv of radiolabeled phosphine, relative to the azide, in aqueous solution resulted in 20-25% efficiency after 2 h. The presence of 37% human serum resulted in a reduced ligation efficiency (reduction max. 30% at 2 h), while the phosphines were still >80% intact. No in vivo Staudinger ligation was observed in a mouse model after injection of 500 μg antibody-azide, followed by 68 μg DFO-phosphine at t = 2 h, and evaluation in blood at t = 7 h. To explain negative results in mice, Staudinger ligation was performed in vitro in mouse serum. Under these conditions, a side product with the phosphine was formed and ligation efficiency was severely reduced. It is concluded that in vivo application of the Staudinger ligation in a pretargeting approach in mice is not feasible, since this ligation reaction is not bioorthogonal and efficient enough. Slow reaction kinetics will also severely restrict the applicability of Staudinger ligation in humans. PMID:21854058

  20. Formation of an iron phosphine-borane complex by formal insertion of BH₃ into the Fe-P bond.

    PubMed

    Frank, Nicolas; Hanau, Katharina; Flosdorf, Kimon; Langer, Robert

    2013-08-21

    A unique hydrido phosphine-borane iron(II) complex [(dppa)(Ph₂P-N-P(BH₃)Ph₂)Fe(H)] (1) was obtained by the reaction of iron(II) chloride and two equivalents of bis(diphenylphosphino)amine (dppa) with an excess of sodium borohydride in acetonitrile-ethanol mixtures. Detailed investigations of the reaction revealed that a mixture of cis- and trans-[(dppa)₂Fe(NCMe)₂]²⁺ is formed prior to the reduction by sodium borohydride. Depending on the solvent, different products were obtained by the reduction: in acetonitrile-ethanol mixtures the hydrido phosphine-borane complex 1 is formed by formal insertion of BH₃, while the reduction in pure acetonitrile results in the formation of the cationic complex trans-[(dppa)₂Fe(H)(NCMe)](BH₄) (4). Complex 4 is remarkably stable in ethanol and does not undergo phosphine-borane formation, even in the presence of excess sodium borohydride. This observation suggests that the phosphine-borane complex is generated by the reaction with the first equivalent of sodium borohydride with the participation of ethanol, followed by deprotonation or dihydrogen elimination. Experiments with similar diphosphine ligands, such as bis(diphenylphosphino)methane, did not yield a phosphine-borane complex, indicating the crucial role of the amine group in the observed reactivity. PMID:23811820

  1. Facile Insertion of Rh and Ir into a Boron-Phenyl Bond, Leading to Boryl/Bis(phosphine) PBP Pincer Complexes.

    PubMed

    Shih, Wei-Chun; Gu, Weixing; MacInnis, Morgan C; Timpa, Samuel D; Bhuvanesh, Nattamai; Zhou, Jia; Ozerov, Oleg V

    2016-02-24

    The unexpectedly facile insertion of Rh or Ir into a B-Ph bond (reversible for Rh) converts a borane/bis(phosphine) precursor into a boryl/bis(phosphine) PBP pincer ligand. Interconversions between the boryl/borane/borate central functionality are demonstrated in reactions with dihydrogen. PMID:26824249

  2. Liquid-liquid extraction of gallium(III) from acidic nitrate media with bis(2-ethylhexyl) phosphinic acid in toluene

    SciTech Connect

    Naik, M.T.; Dhadke, P.M.

    1999-09-01

    The distribution equilibria of gallium(III) between bis(2-ethylhexyl) phosphinic acid dissolved in toluene and acidic aqueous nitrate media has been investigated as a function of the concentration of extractant in organic phase and concentration of hydrogen ion and gallium(III) ion in aqueous phase. The extraction characteristics of bis(2-ethylhexyl) phosphinic acid are compared with that of bis(2-ethylhexyl) phosphoric acid to get further information. The stoichiometry of the extracted species is determined on the basis of slope analysis and IR spectra. Gallium is extracted by a cation exchange mechanism as GaR{sub 3} by bis(2-ethylhexyl) phosphinic acid and as GaR{sub 3}{center{underscore}dot}HR by bis(2-ethylhexyl) phosphoric acid. Temperature dependence of the extraction equilibrium is examined by temperature variation method. Both extraction processes are endothermic in nature and increase in temperature is favorable.

  3. Phosphine-free synthesis of Ag-In-Se alloy nanocrystals with visible emissions

    NASA Astrophysics Data System (ADS)

    Yao, Dong; Liu, Huiwen; Liu, Yi; Dong, Chunwei; Zhang, Kai; Sheng, Yu; Cui, Jianli; Zhang, Hao; Yang, Bai

    2015-11-01

    As promising heavy metal-free emitting materials, Ag-In-Se nanocrystals (NCs) are conventionally synthesized using organic phosphine agents and exhibit near-infrared emissions. In this work, we demonstrate a rapid phosphine-free approach for synthesizing Ag-In-Se alloy NCs with the emissions tunable to the visible region on the basis of the phosphine-free dissolution of Se powder. At room temperature, Se powder is reduced by dodecanethiol and dissolved in oleylamine to produce a Se precursor. The resultant Se precursor is highly active, which permits rapid synthesis at a relatively low temperature, such as at 90 °C for 150 s. By optimizing the size, structure, and composition, the photoluminescence quantum yield of the as-synthesized Ag-In-Se NCs is enhanced to up to 10%. The growth of the Ag-In-Se NCs involves composition and phase transition, which strongly depend on the reaction temperature. The Ag2Se nuclei form first, and the Ag-In-Se NCs are produced by doping In3+ into the preformed Ag2Se nuclei. Tetragonal phase Ag-In-Se is obtained below 170 °C, while the orthorhombic phase appears over 190 °C. The potential of Ag-In-Se NCs as red emitting phosphors for lighting-emitting diodes is further demonstrated.As promising heavy metal-free emitting materials, Ag-In-Se nanocrystals (NCs) are conventionally synthesized using organic phosphine agents and exhibit near-infrared emissions. In this work, we demonstrate a rapid phosphine-free approach for synthesizing Ag-In-Se alloy NCs with the emissions tunable to the visible region on the basis of the phosphine-free dissolution of Se powder. At room temperature, Se powder is reduced by dodecanethiol and dissolved in oleylamine to produce a Se precursor. The resultant Se precursor is highly active, which permits rapid synthesis at a relatively low temperature, such as at 90 °C for 150 s. By optimizing the size, structure, and composition, the photoluminescence quantum yield of the as-synthesized Ag-In-Se NCs is enhanced to up to 10%. The growth of the Ag-In-Se NCs involves composition and phase transition, which strongly depend on the reaction temperature. The Ag2Se nuclei form first, and the Ag-In-Se NCs are produced by doping In3+ into the preformed Ag2Se nuclei. Tetragonal phase Ag-In-Se is obtained below 170 °C, while the orthorhombic phase appears over 190 °C. The potential of Ag-In-Se NCs as red emitting phosphors for lighting-emitting diodes is further demonstrated. Electronic supplementary information (ESI) available: Additional characterization of Ag-In-Se and Ag2Se NCs. See DOI: 10.1039/c5nr04856g

  4. The relation between phosphine sorption and terminal gas concentrations in successful fumigation of food commodities.

    PubMed

    Reddy, Palvai Vanitha; Rajashekar, Yellappa; Begum, Khamrunissa; Leelaja, Bhadravathi Chandrappa; Rajendran, Somiahnadar

    2007-01-01

    Owing to increased tolerance and the development of resistance in stored product insects to the fumigant phosphine, in recent years there has been a shift in the target terminal concentration from 100 ppm (100 mL m(-3)) to a higher level of 1000 ppm to achieve 100% insect mortality in 7 day commodity treatments. Therefore, there is a need to investigate whether the revised target concentration could be achieved for food commodities fumigated with phosphine at the standard dose of 2 g m(-3) for 7 days under airtight conditions at > or = 25 degrees C. When different types of food commodity (total 74) were fumigated (300 g per replicate) with phosphine at 2 g m(-3) for 7 days, the terminal gas concentrations in the free space of the commodities varied from 0 to > 2000 ppm. In chambers containing no substrate, a 1417 ppm concentration was recorded. Paddy rice, most of the oilseeds, shelled tree nuts, butter beans, cardamom, green gram splits, coriander powder, rice bran and cocoa powder were more sorptive (> or =60%), such that the target concentration of 1000 ppm was not achieved at the end of 7 days. For these commodities, increased doses of 3-6 g m(-3) were required to attain 1000 ppm. In-shell almonds, green cardamom, in-shell peanuts, leaf tea, tamarind pulp and sunflower seeds were exceptionally sorptive (>90%), so that 0, 41, 112, 168, 203 and 217 ppm respectively were noted at the end of 7 days; the dose must exceed 6 g m(-3) for effective fumigation of these commodities. PMID:17051623

  5. Tris(pyrazolyl)phosphines with copper(i): from monomers to polymers.

    PubMed

    Tazelaar, Cornelis G J; Nicolas, Emmanuel; van Dijk, Tom; Broere, Daniël L J; Cardol, Mitchel; Lutz, Martin; Gudat, Dietrich; Slootweg, J Chris; Lammertsma, Koop

    2016-02-01

    The parent tris(pyrazolyl)phosphine and its 3,5-Me2, 3-Ph, and 3-t-Bu derivatives have been prepared by a simple procedure and show modest Lewis basicity of the phosphorus apex as was established by the magnitude of the (1)JP,Se coupling constant of the phosphine selenides. Because of the chelating properties of both the N- and P-sites, neutral phosphorus-centered scorpion ligands allow coordination modes that are unavailable to the abundantly used anionic tris(pyrazolyl)borate scorpionates as we established for Cu(i)-complexation. The substituted P-scorpion ligands only allow for N-coordination, as the P-apex is presumably less accessible. Two X-ray crystal structures were obtained for the Cu-complex of tris(3,5-dimethylpyrazolyl)-phosphine with acetonitrile and triphenylphosphine in the fourth coordination site. The parent P-scorpion ligand can chelate with both its pyrazolyl groups and its P-apex with the product depending on the ratio in which it is mixed with the Cu(i) complex. Reacting two equivalents of the ligand with [Cu(MeCN)4][PF6] resulted in a complex in which Cu is coordinated to the three pyrazolyl groups of one ligand and to the P-apex of the other ligand as confirmed by an X-ray crystal structure determination and a DFT computational analysis. Reacting the ligand and the Cu(i) complex in an equimolar ratio resulted in a remarkable one-dimensional P-scorpion coordination polymer for which a single crystal X-ray structure could be determined. A detailed analysis of the structural features is presented. PMID:26596769

  6. Genetic Conservation of Phosphine Resistance in the Rice Weevil Sitophilus oryzae (L.).

    PubMed

    Nguyen, Tam T; Collins, Patrick J; Duong, Tu M; Schlipalius, David I; Ebert, Paul R

    2016-05-01

    High levels of resistance to phosphine in the rice weevil Sitophilus oryzae have been detected in Asian countries including China and Vietnam, however there is limited knowledge of the genetic mechanism of resistance in these strains. We find that the genetic basis of strong phosphine resistance is conserved between strains of S. oryzae from China, Vietnam, and Australia. Each of 4 strongly resistant strains has an identical amino acid variant in the encoded dihydrolipoamide dehydrogenase (DLD) enzyme that was previously identified as a resistance factor in Rhyzopertha dominica and Tribolium castaneum. The unique amino acid substitution, Asparagine > Threonine (N505T) of all strongly resistant S. oryzae corresponds to the position of an Asparagine > Histidine variant (N506H) that was previously reported in strongly resistant R. dominica. Progeny (F16 and F18) from 2 independent crosses showed absolute linkage of N505T to the strong resistance phenotype, indicating that if N505T was not itself the resistance variant that it resided within 1 or 2 genes of the resistance factor. Non-complementation between the strains confirmed the shared genetic basis of strong resistance, which was supported by the very similar level of resistance between the strains, with LC50 values ranging from 0.20 to 0.36mg L(-1) for a 48-h exposure at 25 °C. Thus, the mechanism of high-level resistance to phosphine is strongly conserved between R. dominica, T. castaneum and S. oryzae. A fitness cost associated with strongly resistant allele was observed in segregating populations in the absence of selection. PMID:26774057

  7. Prediction of 31P nuclear magnetic resonance chemical shifts for phosphines

    NASA Astrophysics Data System (ADS)

    Tong, Jianbo; Liu, Shuling; Zhang, Shengwan; Li, Shengshi Z.

    2007-07-01

    Quantitative relationships of the 31P NMR chemical shifts of the phosphorus atoms in 291 phosphines with the atomic ionicity index (INI) and stereoscopic effect parameters ( ɛα, ɛβ, ɛγ) were primarily investigated in this paper for modeling some fundamental quantitative structure-spectroscopy relationships (QSSR). The results indicated that the 31P NMR chemical shifts of phosphines can be described as the quantitative equation by multiple linear regression (MLR): δp (ppm) = -174.0197 - 2.6724 INI + 40.4755 ɛα + 15.1141 ɛβ - 3.1858 ɛγ, correlation coefficient R = 0.9479, root mean square error (rms) = 13.9, and cross-validated predictive correlation coefficient was found by using the leave-one-out procedure to be Q2 = 0.8919. Furthermore, through way of random sampling, the estimative stability and the predictive power of the proposed MLR model were examined by constructing data set randomly into both the internal training set and external test set of 261 and 30 compounds, respectively, and then the chemical shifts were estimated and predicted with the training correlation coefficient R = 0.9467 and rms = 13.4 and the external predicting correlation coefficient Qext = 0.9598 and rms = 10.8. A partial least square model was developed that produced R = 0.9466, Q = 0.9407 and Qext = 0.9599, respectively. Those good results provided a new, simple, accurate and efficient methodology for calculating 31P NMR chemical shifts of phosphines.

  8. Asymmetric Synthesis of Chiral Atropisomeric Bis-Aryl Organophosphorus from Menthyl H-Phosphinate.

    PubMed

    Ma, Yan-Na; Yang, Shang-Dong

    2016-04-01

    This review describes new methods for the synthesis of chiral monophosphine ligands with menthyl phenylphosphinate as a chiral auxiliary through asymmetric Suzuki-Miyaura cross-coupling reactions and asymmetric C-H functionalization. The chiral menthyl phenylphosphinate as a chiral auxiliary is easy to prepare and the menthyl group can easily be transformed into other functional groups, with the chiral center synchronously remaining. These methodologies provide highly efficient and practical strategies for the synthesis of novel axially chiral biaryl monophosphine oxides and their corresponding phosphines. Meanwhile, these reactions are easy to handle and exhibit wide scope for substrates with excellent diastereomeric ratios. PMID:26991107

  9. Photochemical dimerization and functionalization of alkanes, ethers, primary and secondary alcohols, phosphine oxides and silanes

    DOEpatents

    Crabtree, Robert H.; Brown, Stephen H.

    1989-01-01

    The space-time yield and/or the selectivity of the photochemical dimerization of alkanes, ethers, primary and secondary alcohols, phosphine oxides and primary, secondary and tertiary silanes with Hg and U.V. light is enhanced by refluxing the substrate in the irradiated reaction zone at a temperature at which the dimer product condenses and remains condensed promptly upon its formation. Cross-dimerization of the alkanes, ethers and silanes with primary alcohols is disclosed, as is the functionalization to aldehydes of the alkanes with carbon monoxide.

  10. Photochemical dimerization and functionalization of alkanes, ethers, primary and secondary alcohols, phosphine oxides and silanes

    DOEpatents

    Crabtree, R.H.; Brown, S.H.

    1989-10-17

    The space-time yield and/or the selectivity of the photochemical dimerization of alkanes, ethers, primary and secondary alcohols, phosphine oxides and primary, secondary and tertiary silanes with Hg and U.V. light is enhanced by refluxing the substrate in the irradiated reaction zone at a temperature at which the dimer product condenses and remains condensed promptly upon its formation. Cross-dimerization of the alkanes, ethers and silanes with primary alcohols is disclosed, as is the functionalization to aldehydes of the alkanes with carbon monoxide.

  11. Reduction of 4-azidonaphthalimide with different phosphine ligands and exploration of their spectroscopic properties

    NASA Astrophysics Data System (ADS)

    Xu, Shou De; Fang, Cheng Hui; Tian, Guang Xuan; Chen, Yi; Dou, Ye Hong; Kou, Jun Feng; Wu, Xiang Hua

    2015-12-01

    A convenient, high efficient method for the reduction of 4-azidonaphthalimide to 4-aminonaphthalimide (1) by using PMe3 has been developed. Several 4-substituted 1,8-naphthalimide iminophosphoranes were also successfully synthesized. Their structures were characterized by NMR and MS analyses. The structures of compounds 2 and 3 were also confirmed by single crystal X-ray diffraction analysis. Their optoelectronic properties of these naphthalimides were investigated. The results indicated that their optical properties could be tuned by different phosphine ligands, which make them novel potential organic luminescent materials.

  12. Water-Soluble Iridium-NHC-Phosphine Complexes as Catalysts for Chemical Hydrogen Batteries Based on Formate.

    PubMed

    Horváth, Henrietta; Papp, Gábor; Szabolcsi, Roland; Kathó, Ágnes; Joó, Ferenc

    2015-09-21

    Molecular hydrogen, obtained by water electrolysis or photocatalytic water splitting, can be used to store energy obtained from intermittent sources such as wind and solar power. The storage and safe transportation of H2 , however, is an open and central question in such a hydrogen economy. Easy-to-synthesize, water-soluble iridium-N-heterocyclic carbene-phosphine (Ir(I) -NHC-phosphine) catalysts show unprecedented high catalytic activity in dehydrogenation of aqueous sodium formate. Fast reversible generation and storage of hydrogen can be achieved with these catalysts by a simple decrease or increase in the hydrogen pressure, respectively. PMID:26289830

  13. Antioxidant Enzyme Inhibitor Role of Phosphine Metal Complexes in Lung and Leukemia Cell Lines

    PubMed Central

    Keleş, Tuğba; Serindağ, Osman

    2014-01-01

    Phosphine metal complexes have been recently evaluated in the field of cancer therapy. In this research, the cytotoxic effects of some metal phosphines {[PdCl2((CH2OH)2PCH2)2NCH3] (C1), [RuCl2(((CH2OH)2PCH2)2NCH3)2] (C2), [PtCl2((Ph2PCH2)2NCH3)(timin)2] (C3)} on K562 (human myelogenous leukemia cell line) and A549 (adenocarcinomic human alveolar basal epithelial cells) cells were investigated using the MTT test. C1 and C2 are water-soluble metal complexes, which may have some advantages in in vitro and in vivo studies. The effects of the above-mentioned metal complexes on thioredoxin reductase (TrxR) (EC: 1.8.1.9), glutathione peroxidase (GPx) (EC: 1.11.1.9), and catalase (Cat) (EC: 1.11.1.6) enzymes were also tested. The results of this research showed that all three metal complexes indicated dose-dependent cytotoxicity on A549 and K562 cell lines and that the complexes inhibited different percentages of the TrxR, GPx, and Cat enzymes of these tumor cells. PMID:25610346

  14. Effects of Phosphine-Carbene Substitutions on the Electrochemical and Thermodynamic Properties of Nickel Complexes

    SciTech Connect

    Galan, Brandon R.; Wiedner, Eric S.; Helm, Monte L.; Linehan, John C.; Appel, Aaron M.

    2014-05-12

    Nickel(II) complexes containing chelating N-heterocyclic carbene-phosphine ligands ([NiL2](BPh4)2, for which L = [MeIm(CH2)2PR2]) have been synthesized for the purpose of studying how this class of ligand effects the electrochemical properties compared to the nickel bis- diphosphine analogues. The nickel complexes were synthesized and characterized by x-ray crystallography and electrochemical methods. Based on the half wave potentials (E1/2), substitution of an NHC for one of the phosphines in a diphoshine ligand results in shifts in potential to 0.6 V to 1.2 V more negative than the corresponding nickel bis-diphosphine complexes. These quantitative results highlight the substantial effect that NHC ligands can have upon the electronic properties of the metal complexes. BRG, JCL, and AMA acknowledge the support by the US Department of Energy Basic Energy Sciences, Division of Chemical Sciences, Geosciences & Biosciences. MLH acknoledges the support of the Center for Molecular Electrocatalysis, an Energy Frontier Research Center funded by the US Department of Energy, Office of Science, Office of Basic Energy Sciences. Pacific Northwest National Laboratory is operated by Battelle for the US Department of Energy.

  15. /sup 31/P and /sup 119/Sn NMR of adducts of tin tetrahalides with tertiary phosphines

    SciTech Connect

    Yashina, N.S.; Gefel, E.I.; Kosina, A.N.; Petrosyan, V.S.; Reutov, O.A.

    1986-10-01

    The donor-acceptor interaction of SnX/sub 4/ (X = Cl, Br) with tertiary phosphines (nBu/sub 3/P, Me/sub 2/PhP, Ph/sub 3/P) has been studied by /sup 31/P and /sup 119/Sn spectroscopy over a broad range of temperatures and with varous donor-acceptor ratios (D/A) in solutions in methylene chloride. An analysis of the direct spin-spin coupling constants /sup 1/J(/sup 119/Sn-/sup 31/P) and the multiplicity in the /sup 119/Sn NMR spectra made it possible to propose a complexation mechanism, which includes the formation of intermediate ionic structures along with the molecular complexes AD and AD/sub 2/. It has been shown that an excess of the acceptor is not a sufficient condition for the formation of the complex AD. The coexistence of cis and trans isomers of the AD/sub 2/ complexes in solution has been established, and the dependence of /sup 1/J(/sup 119/Sn-/sup 31/P) on the geometry of the P-Sn-P fragment in the octahedral complexes has been demonstrated. The use of low-temperature NMR made it possible, in most cases, to suppress the occurrence of the redox reaction between the compounds of Sn(IV) and the tertiary phosphines.

  16. Atomistic Simulations of Perfluoro Phosphonic and Phosphinic Acid Membranes and Comparisons to Nafion

    SciTech Connect

    Idupulapati, Nagesh B.; Devanathan, Ramaswami; Dupuis, Michel

    2011-03-31

    We used classical molecular dynamics (MD) simulations to investigate the nanoscale morphology and proton transport properties of perfluoro phosphonic (FPA) and phosphinic acid (FPA-I) membranes as they are being considered for use in low temperature fuel cells. We systematically investigated these properties as a function of the hydration level. The changes in nanostructure, in transport dynamics of water and hydronium ions, and in water network percolation were extracted from MD simulations and compared with Nafion. Phosphonic and phosphinic acid moieties in FPA and FPA-I, have lower acidity than sulfonic acid in Nafion, yet the diffusion of water was observed to be faster in FPA and FPA-I than in Nafion, particularly at low hydration levels. However this did not give rise to notable differences in hydronium ion diffusion and water network percolation for these membranes over Nafion. Similar observations were also reported by our group recently in a study of perfluoro-sulfonyl imide membranes carrying stronger super-acids than sulfonic acid of Nafion. These findings together suggest no strong apparent correlation between the acidity strength of the functional acid groups and the dynamics of water and hydronium ions in hydrated polymer electrolyte membranes (PEMs) with similar fluorocarbon backbones and acidic group-carrying side chains. This work was supported by the US Department of Energy Basic Energy Sciences' Chemical Sciences, Geosciences & Biosciences Division. Pacific Northwest National Laboratory is operated by Battelle for the US Department of Energy.

  17. Activation of Single-Component Nickel(II) Polyethylene Catalysts via Phase Transfer of Fluorous Phosphine Ligands.

    PubMed

    Xi, Zhenxing; Bazzi, Hassan S; Gladysz, John A

    2015-09-01

    The nickel salicylaldiminato phosphine complexes [1,2,3-C6H3(9-anthracenyl)O(CH═N(2,6-C6H3(iPr)2)]Ni(Me)[P(4-C6H4R)3] (4; R = a, (CH2)2Rf8; b, (CH2)3Rf8; c, H (Rf8 = (CF2)7CF3)) are prepared from the corresponding phosphines 3a-c and nickel NCMe adduct (46-68%). These are applied as catalysts for ethylene polymerization in toluene and fluorous/toluene liquid/liquid biphasic mixtures. Under the latter conditions, the fluorous phosphines 3a,b that must dissociate to generate the active catalyst migrate to the fluorous phase (partition coefficients 97.5:2.5 and 66.6:33.4 vs <0.5:>99.5 for 4a,b). Catalysts 4a,b show marked accelerations under biphasic conditions, but 4c (which has a lipophilic phosphine ligand) does not. Under all conditions, 4a,b are faster catalysts than the Ni(Ph)(PPh3) analogue, a previously reported benchmark. PMID:26300472

  18. Phosphine-catalyzed [4 + 1] annulation between α,β-unsaturated imines and allylic carbonates: synthesis of 2-pyrrolines.

    PubMed

    Tian, Junjun; Zhou, Rong; Sun, Haiyun; Song, Haibin; He, Zhengjie

    2011-04-01

    In this report, a phosphine-catalyzed [4 + 1] annulation between α,β-unsaturated imines and allylic carbonates is described. This reaction represents the first realization of catalytic [4 + 1] cyclization of 1,3-azadienes with in situ formed phosphorus ylides, which provides highly efficient and diastereoselective synthesis of 2-pyrrolines. PMID:21384931

  19. Pure phosphine fumigation treatment at low temperature for postharvest control of western flower thrips on lettuce, broccoli, asparagus, and strawberries

    Technology Transfer Automated Retrieval System (TEKTRAN)

    U.S. exported lettuce, broccoli, asparagus, and strawberries often harbor western flower thrips (Frankliniella occidentalis), a quarantined pest in Taiwan, and therefore require quarantine treatment. Pure phosphine fumigation at a low temperature of 2°C was studied as an alternative fumigant to meth...

  20. Synthesis of vinylphosphines and unsymmetric diphosphines: iron-catalyzed selective hydrophosphination reaction of alkynes and vinylphosphines with secondary phosphines.

    PubMed

    Itazaki, Masumi; Katsube, Shinya; Kamitani, Masahiro; Nakazawa, Hiroshi

    2016-02-11

    Iron complex-catalyzed regioselective single hydrophosphination of terminal arylalkynes with secondary phosphines was achieved. Unsymmetric 1,2-bis(phosphino)ethanes with different phosphino groups were obtained by using our catalytic systems. The structures of the obtained vinylphosphine, unsymmetric 1,2-bis(phosphino)ethane, and iron catalyst precursors were confirmed by single crystal X-ray diffraction studies. PMID:26805625

  1. Enantioselective [4 + 2]-Annulation of Oxadienes and Allenones Catalyzed by an Amino Acid Derived Phosphine: Synthesis of Functionalized Dihydropyrans.

    PubMed

    Ni, Huanzhen; Yao, Weijun; Waheed, Abdul; Ullah, Nisar; Lu, Yixin

    2016-05-01

    An enantioselective [4 + 2]-annulation process between cyano-activated oxadienes and allenones is developed. An l-valine-derived phosphine was efficient in catalyzing the reaction, and a wide range of highly functionalized dihydropyrans were prepared in high yields and with excellent enantioselectivities. PMID:27091405

  2. Copper(I)-Catalyzed Asymmetric Pinacolboryl Addition of N-Boc-imines Using a Chiral Sulfoxide-Phosphine Ligand.

    PubMed

    Wang, Ding; Cao, Peng; Wang, Bing; Jia, Tao; Lou, Yazhou; Wang, Min; Liao, Jian

    2015-05-15

    Highly efficient and enantioselective copper(I)-catalyzed pinacolboryl addition of N-Boc-imines is reported. By using a single chiral sulfoxide-(dialkyl)phosphine (SOP) ligand, both enantiomeric isomers of α-amino boronic esters were obtained through an achiral counteranion switch. PMID:25906191

  3. Anticancer Agents: Does a Phosphonium Behave Like a Gold(I) Phosphine Complex? Let a "Smart" Probe Answer!

    PubMed

    Ali, Moussa; Dondaine, Lucile; Adolle, Anais; Sampaio, Carla; Chotard, Florian; Richard, Philippe; Denat, Franck; Bettaieb, Ali; Le Gendre, Pierre; Laurens, Véronique; Goze, Christine; Paul, Catherine; Bodio, Ewen

    2015-06-11

    Gold phosphine complexes, such as auranofin, have been recognized for decades as antirheumatic agents. Clinical trials are now underway to validate their use in anticancer or anti-HIV treatments. However, their mechanisms of action remain unclear. A challenging question is whether the gold phosphine complex is a prodrug that is administered in an inactive precursor form or rather that the gold atom remains attached to the phosphine ligand during treatment. In this study, we present two novel gold complexes, which we compared to auranofin and to their phosphonium analogue. The chosen ligand is a phosphine-based smart probe, whose strong fluorescence depends on the presence of the gold atom. The in vitro biological action of the gold complexes and the phosphonium derivative were investigated, and a preliminary in vivo study in healthy zebrafish larvae allowed us to evaluate gold complex biodistribution and toxicity. The different analyses carried out showed that these gold complexes were stable and behaved differently from phosphonium and auranofin, both in vitro and in vivo. Two-photon microscopy experiments demonstrated that the cellular targets of these gold complexes are not the same as those of the phosphonium analogue. Moreover, despite similar IC50 values in some cancer cell lines, gold complexes displayed a low toxicity in vivo, in contrast to the phosphonium salt. They are therefore suitable for future in vivo investigations. PMID:25973667

  4. Iridium(I) N-Heterocyclic Carbene (NHC)/Phosphine Catalysts for Mild and Chemoselective Hydrogenation Processes.

    PubMed

    Kerr, William J; Mudd, Richard J; Brown, Jack A

    2016-03-24

    The directed chemoselective hydrogenation of olefins has been established by using iridium(I) catalysts, which feature a tuned NHC/phosphine ligand combination. This selective reduction process has been demonstrated in a wide array of solvents, including more environmentally acceptable media, also allowing further refinement of hydrogenation selectivity. PMID:26854284

  5. Oxygenated phosphine fumigation for control of light brown apple moth, Epiphyas postvittana (Lepidoptera: Tortricidae), eggs on cut-flowers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Light brown apple moth, Epiphyas postvittana, eggs were subjected to oxygenated phosphine fumigation treatments on cut flowers to determine efficacy and safety. Five cut flower species: roses, lilies, tulips, gerbera daisy, and pompon chrysanthemums, were fumigated in separate groups with 2500 ppm ...

  6. Chloridotris(pentafluorobenzenethiolato-?S)[tris(4-fluorophenyl)phosphine-?P]osmium(IV)

    PubMed Central

    Arias, Asdrbal; Melndez, Lidia; Berns, Sylvain; Arroyo, Maribel

    2010-01-01

    The title complex, [Os(C6F5S)3Cl(C18H12F3P)], displays a trigonal-bipyramidal OsIV coordination geometry with the S atoms of three thiolate ligands occupying the equatorial positions. The thiolate pentafluorophenyl substituents are all placed above the equatorial plane, forming a claw-like cavity which accommodates the chloride ligand with a normal OsCl bond length. The phosphine ligand trans to the chloride ligand reveals a short OsP bond length compared to other chloridephosphine OsIV complexes (average = 2.40?). This strong bonding indicates that the inductive effect of the F atoms in the phosphine does not affect significantly its basicity, compared to triphenylphosphine. This feature is also consistent with the known poor trans influence of Cl?. The crystal packing involves ?? contacts between inversion-related thiolate C6F5 rings, with a centroidcentroid separation of 3.659?(8)?. PMID:21580558

  7. Microstructure degradation of YSZ in Ni/YSZ anodes of SOFC operated in phosphine-containing fuels

    SciTech Connect

    Chen, Yun; Chen, Song; Hackett, Gregory; Finklea, Harry; Zondlod, John; Celik, Ismail; Song, Xueyan; Gerdes, Kirk

    2013-03-07

    The interaction of trace (ppm) phosphine with the nickel/yttria stabilized zirconia (YSZ) anode of commercial solid oxide fuel cells has been investigated and evaluated for both synthesis gas and hydrogen fuels in an effort to examine P–Y reactions. The Ni poisoning effects reported in literature were confirmed and degradation was examined by electrochemical methods and post-test microstructural and chemical analyses. The results indicate that P-induced degradation rates and mechanisms are fuel dependent and that degradation of cells operated in synthesis gas (syngas) with phosphine is more severe than that of cells operated in hydrogen with phosphine. As reported in published literature, a cell operated in syngas containing 10 ppm phosphine demonstrated significant microstructural degradation within the Ni phase, including formation of Ni–P phases concentrated on the outer layer of the anode and significant pitting corrosion in the Ni grains. In this research, a previously undetected YPO{sub 4} phase is observed at the YSZ/YSZ/Ni triple grain junctions located at the interface with the YSZ electrolyte. Tetragonal YSZ (t-YSZ) and cubic-YSZ (c-YSZ) domains with sizes of several tens of nanometers are also newly observed along the Ni/YSZ interface. These observations contrast with data obtained for a cell operated in dry hydrogen with phosphine, where no YPO{sub 4} phase is observed and the alternating t-YSZ and c-YSZ domains at the Ni/YSZ interface are smaller with typical sizes of 5–10 nm. The data imply that electrolyte attack by P is a potentially debilitating mode of degradation in SOFC anodes, and that the associated reaction mechanisms and rates are worthy of further examination.

  8. Flotation performances and adsorption mechanism of α-hydroxyoctyl phosphinic acid to cassiterite

    NASA Astrophysics Data System (ADS)

    Li, Fangxu; Zhong, Hong; Zhao, Gang; Wang, Shuai; Liu, Guangyi

    2015-10-01

    In this paper, the flotation performances and adsorption mechanism of α-hydroxyoctyl phosphinic acid (HPA) to cassiterite were investigated by adsorption experiments, micro-flotation tests, zeta potential measurements, Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analyses. The micro-flotation results indicated that compared with styrene phosphonic acid (SPA), diphosphonic acid (DPA), benzohydroxamic acid (BHA) and salicylhydroxamic acid (SHA), HPA exhibited excellent collecting power to cassiterite and superior selectivity against magnetite or hematite over a wide pH range. The results of adsorption experiments and zeta potential deduced that HPA chemisorb on cassiterite surfaces. The results of FTIR inferred HPA chemisorb onto cassiterite surfaces through its P and O atoms with the P-H and O-H bonds broken. XPS analysis further demonstrated HPA react with Sn species by formation of Sn-O-P and Sn-P bond.

  9. Observations of the J = 10 manifold of the pure rotational band of phosphine on Saturn

    NASA Technical Reports Server (NTRS)

    Haas, M. R.; Erickson, E. F.; Goorvitch, D.; Mckibbin, D. D.; Rank, D. M.

    1986-01-01

    Saturn was observed in the vicinity of the J = 10 manifold of the pure rotational band of phosphine on 1984 July 10 and 12 from NASA's Kuiper Airborne Observatory with the facility far-infrared cooled grating spectrometer. On each night observations of the full disk plus rings were made at 4 to 6 discrete wavelengths which selectively sampled the manifold and the adjacent continuum. The previously reported detection of this manifold is confirmed. After subtraction of the flux due to the rings, the data are compared with disk-averaged models of Saturn. It is found that PH3 must be strongly depleted above the thermal inversion (approx. 70 mbar). The best fitting models consistent with other observational constaints indicate that PH3 is significantly depleted at even deeper atmospheric levels ( or = 500 mbar), implying an eddy diffusion coefficient for Saturn of 10 to the 4 cm sq/sec.

  10. Phosphine Oxides as Stabilizing Ligands for the Palladium-Catalyzed Cross-Coupling of Potassium Aryldimethylsilanolates

    PubMed Central

    Denmark, Scott E.; Smith, Russell C.; Tymonko, Steven A.

    2012-01-01

    The palladium-catalyzed cross-coupling reaction of potassium (4-methoxyphenyl)dimethylsilanolate (K+1−) with aryl bromides has been demonstrated using triphenylphosphine oxide as a stabilizing ligand. Unsymmetrical biaryls can be prepared from a variety of aryl bromides in good yield with short reaction times. Qualitative kinetics studies compared effects of different phosphine oxides on the rate of cross-coupling and established the beneficial effect of these ligands in the reaction of electron-rich arylsilanolates. The improved yield and reproducibility of the cross-coupling of several bromides was demonstrated by direct comparison of reactions performed with and without triphenylphosphine oxide under non-rigorous exclusion of oxygen. PMID:23162169

  11. Nickel Phosphine Catalysts with Pendant Amines for Electrocatalytic Oxidation of Alcohols

    SciTech Connect

    Weiss, Charles J.; Wiedner, Eric S.; Roberts, John A.; Appel, Aaron M.

    2015-01-01

    Nickel phosphine complexes with pendant amines have been found to be electrocatalysts for the oxidation of primary and secondary alcohols, with turnover frequencies as high as 3.3 s-1. These complexes are the first electrocatalysts for alcohol oxidation based on non-precious metals, which will be critical for use in fuel cells. The research by CJW, ESW, and AMA was supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences & Biosciences. The research by JASR was supported as part of the Center for Molecular Electrocatalysis, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science. Pacific Northwest National Laboratory is operated by Battelle for the US Department of Energy.

  12. Synthesis and characterization of aryl phosphine oxide containing thermoplastic polyimides and thermosetting polyimides with controlled reactivity

    NASA Astrophysics Data System (ADS)

    Zhuang, Hong

    1998-11-01

    Phosphorus containing monomers, bis(3-aminophenyl)methyl phosphine oxide (m-DAMPO) and bis(3-aminophenyl)phenyl phosphine oxide (m-DAPPO), were synthesized and incorporated into a thermoplastic poly(arylene ether imide) based upon 2,2sp'-bis (4-(3,4-dicarboxyphenoxy)phenyl) propane dianhydride and 1,3-phenylene diamine, in order to study their influence on flame resistance and other properties. DAMPO or DAPPO were quantitatively incorporated in concentrations of 25, 50, 75 and 100 mole percent, using the "one pot" ester-acid method. The number average molecular weights of the prepared materials were controlled to 20,000g/mol by off-setting the stoichiometry and endcapping with phthalic anhydride. This strategy enabled one to distinguish the effects of the phosphine oxide incorporation from the influence of molecular weight. The resulting copolymers demonstrated a significant increase in char yield as a function of the phosphine oxide content, thus suggesting improved fire resistance. Glass transition temperatures similar to the control were determined by DSC analysis. Analysis of the mechanical behavior of the DAMPO system at room temperature showed that tensile strength and elongation at failure values were comparable to the control system, while the DAPPO containing copolymers were surprisingly brittle. The influence of the reactive endgroup on the synthesis, cure behavior and network properties of thermosetting polyetherimides was investigated. Reactive phenylacetylene, acetylene and maleimide terminated poly(ether imide) oligomers were prepared and characterized. Optimal reaction conditions were established to produce fully endcapped oligomers with imidized structures and controlled molecular weight. The phenylacetylene endcapped system was synthesized by a conventional ester-acid method. The acetylene endcapped system was prepared via modified ester-acid method and the maleimide endcapped system was fabricated utilizing an amic-acid route. It was determined that phenylethynyl endcapped polymers could be thermally cured at high temperatures (350{-}380sp°C) providing good processibility. The networks exhibited thermal stability, chemical resistance and good adhesion strength, ideal as "primary" bonding adhesives. Acetylene and maleimide endcapped systems were prepared for application as "secondary" bonding materials, meaning that they are cured at a lower temperature than that of the Tg of the primary structure. Lap shear test results indicated good adhesion to titanium when cured at 250sp° C{-}280sp° C. The cured materials showed high glass transition temperatures and good thermal and thermo-oxidative stability as determined by DSC, TGA and DMA. Good chemical resistance was demonstrated via solvent extraction measurements. The influence of molecular weight between crosslinks (/line{M}sb{c}) on thermal and mechanical behavior was also investigated. Lower molecular weight oligomers exhibited lower Tg and cure temperatures, whereas the cured networks resulting from lower molecular weight oligomers afforded higher Tg and higher gel fractions, but reduced toughness.

  13. Cooperative titanocene and phosphine catalysis: accelerated C-X activation for the generation of reactive organometallics.

    PubMed

    Fleury, Lauren M; Kosal, Andrew D; Masters, James T; Ashfeld, Brandon L

    2013-01-18

    The study presented herein describes a reductive transmetalation approach toward the generation of Grignard and organozinc reagents mediated by a titanocene catalyst. This method enables the metalation of functionalized substrates without loss of functional group compatibility. Allyl zinc reagents and allyl, vinyl, and alkyl Grignard reagents were generated in situ and used in the addition to carbonyl substrates to provide the corresponding carbinols in yields up to 99%. It was discovered that phosphine ligands effectively accelerate the reductive transmetalation event to enable the metalation of C-X bonds at temperatures as low as -40 °C. Performing the reactions in the presence of chiral diamines and amino alcohols led to the enantioselective allylation of aldehydes. PMID:23094703

  14. Practical Peptide Synthesis Mediated by a Recyclable Hypervalent Iodine Reagent and Tris(4-methoxyphenyl)phosphine.

    PubMed

    Zhang, Chi; Liu, Shan-Shan; Sun, Bo; Tian, Jun

    2015-08-21

    6-(3,5-Bis(trifluoromethyl)phenyl)-1H,4H-2aλ(3)-ioda-2,3-dioxacyclopenta[hi]indene-1,4-dione (p-BTFP-iodosodilactone, 1a) was synthesized and demonstrated to be an efficient hypervalent iodine(III) reagent for the synthesis of dipeptides from various standard amino acids, including sterically hindered amino acids, in good to high yields within 30 min in the presence of tris(4-methoxyphenyl)phosphine. In addition, the combined system of 1a/(4-MeOC6H4)3P was used to synthesize the pentapeptide leu-enkephalin in protected form. It is worth noting that 1a can be regenerated readily after reaction. PMID:26252539

  15. Comparison of Aromatic Dithiophoshinic and Phosphinic Acid Derivatives for Minor Actinide Extraction

    SciTech Connect

    John R. Klaehn; Dean R. Peterman; Mason K. Harrup; Richard D. Tillotson; Mitchell R. Greenhalgh; Thomas A. Luther; Jack D. Law; Lee M. Daniels

    2008-03-01

    A new extractant for the separation of actinide(III) and lanthanide(III), bis(otrifluoromethylphenyl) phosphinic acid (O-PA) was synthesized. The synthetic route employed mirrors one that was employed to produce the sulfur containing analog bis(otrifluoromethylphenyl) dithiophosphinic acid (S-PA). Multinuclear NMR spectroscopy was used for elementary characterization of the new O-PA derivative. This new O-PA extractant was used to perform Am(III)/Eu(III) separations and the results were directly compared to those obtained in identical separation experiments using S-PA, an extractant that is known to exhibit separation factors of ~100,000 at low pH. The separations data are presented and discussed in terms comparing the nature of the oxygen atom as a donor to that of the sulfur atom in extractants that are otherwise identical.

  16. Comparison of Dithiophosphinic and Phosphinic Acid Derivatives for Minor Actinide Extraction

    SciTech Connect

    Mason K Harrup; Dean R. Peterman; Thomas A. Luther; Mitchell R. Greenhalgh; John R. Klaehn

    2008-03-01

    A new extractant for the separation of actinide(III) and lanthanide(III), bis(otrifluoromethylphenyl) phosphinic acid (O-PA) was synthesized. The synthetic route employed mirrors one that was employed to produce the sulfur containing analog bis(otrifluoromethylphenyl) dithiophosphinic acid (S-PA). Multinuclear NMR spectroscopy was used for elementary characterization of the new O-PA derivative. This new O-PA extractant was used to perform Am(III)/Eu(III) separations and the results were directly compared to those obtained in identical separation experiments using S-PA, an extractant that is known to exhibit separation factors of ~100,000 at low pH. The separations data are presented and discussed in terms comparing the nature of the oxygen atom as a donor to that of the sulfur atom in extractants that are otherwise identical.

  17. Preparation of cadmium selenide-polyolefin composites from functional phosphine oxides and ruthenium-based metathesis.

    PubMed

    Skaff, Habib; Ilker, M Firat; Coughlin, E Bryan; Emrick, Todd

    2002-05-22

    Cadmium selenide nanoparticles, prepared by known methods, were stabilized with functional phosphine oxide 1, then used to support the polymerization of cyclic olefins radially outward from the surface by ruthenium-catalyzed ring-opening metathesis polymerization (ROMP). The conversion of compound 1 into the new metathesis catalyst 3 by carbene exchange and the subsequent polymerization of cyclic olefins were observed spectroscopically by (1)H NMR to afford for example CdSe-polycyclooctene composite 6. Transmission electron micrographs on thin films of these composites showed good nanoparticle dispersion. This is in stark contrast to the substantial nanoparticle aggregation observed when similar polymerizations were performed in the presence of conventional TOPO-covered nanoparticles. The methods reported here to prepare composite product 6 are applicable to other cyclic olefins, and suggest that this chemistry will be useful for incorporating CdSe nanoparticles into a wide variety of polymer matrices. PMID:12010046

  18. Methyltrioxorhenium-catalyzed highly selective dihydroxylation of 1,2-allenylic diphenyl phosphine oxides.

    PubMed

    Hou, Junli; Chen, Yang; Ma, Dongmei; Cordes, Burghard; Wang, Jingyun; Wang, Xin; Khn, Fritz E; Guo, Hao; Zhou, Mingdong

    2015-05-01

    For the first time, methyltrioxorhenium (MTO) has been applied as a catalyst for the dihydroxylation of allenes in the presence of hydrogen peroxide as the oxidant. The regioselectivities turn out to be well controlled, affording ?-carbonyl-?-hydroxyl diphenyl phosphine oxides as the only product. The axial chirality of optically active allenes can also be nicely transferred to the chirality center of the products. Based on chirality transfer experiments and ESI-MS studies of (18)O-labeled products, a possible mechanism, proceeding via regioselective epoxidation of the electron-rich carbon-carbon double bond, a subsequent intermolecular nucleophilic attack of a water molecule on the in situ formed epoxide via neighboring group participation (NGP), followed by a rearrangement has been proposed as the major reaction pathway. PMID:25791269

  19. Effect of phosphines on the thermodynamics of the cobalt catalyzed hydroformylation system.

    SciTech Connect

    Klingler, R. J.; Chen, M. J.; Rathke, J. W.; Kramarz, K. W.; Chemical Engineering; BASF Corp.

    2007-01-01

    Thermodynamic parameters relevant to the phosphine-modified cobalt hydroformylation reaction are reported. Equilibrium constants for the hydrogenation of Co{sub 2}(CO){sub 6}L{sub 2} to yield HCo(CO){sub 3}L were determined using in situ {sup 1}H and {sup 31}P NMR spectroscopy between 75 and 175 C for various solvents and phosphine ligands. Special emphasis was placed on n-Bu{sub 3}P, as this ligand is prototypical of the Shell hydroformylation process. The resultant van't Hoff plots yield the enthalpy and entropy change (H = 7.0 {+-} 0.4 kcal/mol and {Delta}S = 2 {+-} 1 cal/mol {center_dot} K) for the case of L = n-Bu{sub 3}P in benzene solvent. These parameters were found to be relatively insensitive to changes in the solvent, suggesting that the hydride product is not very polar. Even for isobutyl alcohol solvent, the resultant enthalpy and entropy changes (H = 5.8 {+-} 0.4 kcal/mol and S = -2 {+-} 1 cal/mol {center_dot} K) were found to be similar to those obtained in benzene and dioxane. Analysis of the {sup 31}P NMR line widths allows rigorous lower limits to be established for the catalytically relevant Co-Co and Co-H bond energies in the case of L = n-Bu{sub 3}P (Co-Co 23 kcal/mol and Co-H 60 kcal/mol) relative to the previously reported values for the case of L = CO (Co-Co = 19 {+-} 2 kcal/mol and Co-H = 59 {+-} 1 kcal/mol).

  20. Time-dependent density functional theory study of the luminescence properties of gold phosphine thiolate complexes.

    PubMed

    Guidez, Emilie B; Aikens, Christine M

    2015-04-01

    The origin of the emission of the gold phosphine thiolate complex (TPA)AuSCH(CH3)2 (TPA = 1,3,5-triaza-7-phosphaadamantanetriylphosphine) is investigated using time-dependent density functional theory (TDDFT). This system absorbs light at 3.6 eV, which corresponds mostly to a ligand-to-metal transition with some interligand character. The P-Au-S angle decreases upon relaxation in the S1 and T1 states. Our calculations show that these two states are strongly spin-orbit coupled at the ground state geometry. Ligand effects on the optical properties of this complex are also discussed by looking at the simple AuP(CH3)3SCH3 complex. The excitation energies differ by several tenths of an electronvolt. Excited state optimizations show that the excited singlet and triplet of the (TPA)AuSCH(CH3)2 complex are bent. On the other hand, the Au-S bond breaks in the excited state for the simple complex, and TDDFT is no longer an adequate method. The excited state energy landscape of gold phosphine thiolate systems is very complex, with several state crossings. This study also shows that the formation of the [(TPA)AuSCH(CH3)2]2 dimer is favorable in the ground state. The inclusion of dispersion interactions in the calculations affects the optimized geometries of both ground and excited states. Upon excitation, the formation of a Au-Au bond occurs, which results in an increase in energy of the low energy excited states in comparison to the monomer. The experimentally observed emission of the (TPA)AuSCH(CH3)2 complex at 1.86 eV cannot be unambiguously assigned and may originate from several excited states. PMID:25793466

  1. Palladium(ii) complexes featuring a mixed phosphine-pyridine-iminophosphorane pincer ligand: synthesis and reactivity.

    PubMed

    Cheisson, Thibault; Auffrant, Audrey

    2016-02-01

    An original mixed ligand (labelled L) of formula PPh2-CH2-Pyr-CH2-N[double bond, length as m-dash]PPh3, combining a pyridine core with phosphine and iminophosphorane, was synthesised. Its coordination with palladium(ii) centers was studied. With [Pd(COD)Cl2], a cationic complex [LPdCl](Cl) 1, where L is coordinated in the pincer mode, was obtained. Chloride abstraction with silver salt in the presence of pyridine generated the dicationic complex [LPd(py)](BF4)2 (2). When reacting with a base such as potassium hexamethyldisilazane (KHMDS), 1 gave the neutral complex 3 [L*PdCl], wherein the benzylic position alpha to phosphine was selectively deprotonated, which induced dearomatisation of the pyridine ring. A similar complex [L*Pd(CH3)] (4) was obtained upon a reaction of [Pd(CH3)2(TMEDA)] and Lvia the departure of methane. Neutral complexes with the deprotonated ligand such as 3 yielded in the presence of deuterated methanol the corresponding deuterated complex, showing that the protonation is reversible with this ligand. Finally, upon attempting to dealkylate complex 4 using B(C6F5)3, an unexpected zwitterionic borated complex 5, resulting from the formation of a C-B bond in the benzylic position with restoration of the aromatic character of the pyridine, was isolated. Interestingly, when the metal was introduced after the ligand interacted with the borane reagent, another palladium complex formed, namely, [LPdMe][MeB(C6F5)3], originating from methyl abstraction. PMID:26419539

  2. Synthesis and fuel cell characterization of blend membranes from phenyl phosphine oxide containing flourinated novel polymers

    NASA Astrophysics Data System (ADS)

    Gürtekin Seden, Merve; Baştürk, Emre; Inan, Tülay Y.; Kayaman Apohan, Nilhan; Güngör, Atilla

    2014-12-01

    Novel fluorinated poly(arylene ether)'s are synthesized from polycondensation of bis (p-hydroxy-tetrafluoro) phenyl) phenyl phosphine oxide (PFPPO-OH) with 4,4‧-dichlorodiphenyl sulfone (DCDPS) and 2,2-bis(4-hydroxyphenyl)propane (Bisfenol A) (Copolymer 1a) or 2,2-bis(4-hydroxyphenyl) hexafluoropropane (Bisphenol AF) (Copolymer 1b). The fluorinated copolymers have been blended with sulphonated poly(ether ether ketone)-SPEEK by solvent casting method. The water uptake and proton conductivity of the blend membranes decreases with the increase of copolymer content as expected, but proton conductivity values are still comparable to that of Nafion117® membrane. Addition of hydrophobic copolymer 1b to the SPEEK caused increase in water vapor transmission. Methanol permeability of the membranes is decreased to 8.2 × 10-8 cm2 s-1 and 1.3 × 10-9 cm2 s-1 by addition of Copolymer 1a and 1b, respectively and they are much lower than that of Nafion® 117 (1.21E-06 (cm2 s-1). The blend membranes endure up to 6.5 h before it starts to dissolve. Hydrogen and oxygen permeability of the blend membranes is one-hundredth of the Nafion®. Fluorinated polymer improved chemical, mechanical, and hydrolytic stability and also phenyl phosphine oxide structure in the ionomer increased the thermal stability, gas and methanol permeability and overcomed the drawbacks of the Nafion® type membranes.

  3. Mono-Oxidation of Bidentate Bis-phosphines in Catalyst Activation: Kinetic and Mechanistic Studies of a Pd/Xantphos-Catalyzed C-H Functionalization.

    PubMed

    Ji, Yining; Plata, R Erik; Regens, Christopher S; Hay, Michael; Schmidt, Michael; Razler, Thomas; Qiu, Yuping; Geng, Peng; Hsiao, Yi; Rosner, Thorsten; Eastgate, Martin D; Blackmond, Donna G

    2015-10-21

    Kinetic, spectroscopic, crystallographic, and computational studies probing a Pd-catalyzed C-H arylation reaction reveal that mono-oxidation of the bis-phosphine ligand is critical for the formation of the active catalyst. The bis-phosphine mono-oxide is shown to be a hemilabile, bidentate ligand for palladium. Isolation of the oxidative addition adduct, with structural elucidation by X-ray analysis, showed that the mono-oxide was catalytically competent, giving the same reaction rate in the productive reaction as the Pd(II)/xantphos precursor. A dual role for the carboxylate base in both catalyst activation and reaction turnover was demonstrated, along with the inhibiting effect of excess phosphine ligand. The generality of the role of phosphine mono-oxide complexes in Pd-catalyzed coupling processes is discussed. PMID:26461028

  4. Low temperature phosphine fumigation of pre-chilled iceberg lettuce under insulation cover for postharvest control of western flower thrips, Frankliniella occidentalis (Thysanoptera: Thripidae).

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fumigation of chilled iceberg lettuce under an insulation cover was studied to develop economical alternatives to conduct low temperature phosphine fumigation for control of western flower thrips, Frankliniella occidentalis (Pergande), on exported lettuce. Vacuum cooled commercial iceberg lettuce o...

  5. Highly enantioselective synthesis of 3,4-dihydropyrans through a phosphine-catalyzed [4+2] annulation of allenones and β,γ-unsaturated α-keto esters.

    PubMed

    Yao, Weijun; Dou, Xiaowei; Lu, Yixin

    2015-01-14

    A phosphine-catalyzed novel [4+2] annulation process was devised employing allene ketones as C2 synthons and β,γ-unsaturated α-keto esters as C4 synthons. In the presence of an L-threonine-derived bifunctional phosphine, 3,4-dihydropyrans were obtained in high yields and with virtually perfect enantioselectivities. The synthetic value of the dihydropyran motif was demonstrated by a concise preparation of an anti-hypercholesterolemic agent. PMID:25401753

  6. A mechanistic investigation of phosphine migration and substitution in (Fe sub 2 Co(CO) sub 8 (PR sub 3 )(CCO)) sup minus

    SciTech Connect

    Ching, S.; Shriver, D.F. )

    1989-04-26

    The kinetics of phosphine migration from a metal to carbon site in a trimetallic cluster have been investigated. The rate of ligand migration is significantly decreased by bulky phosphines and is relatively insensitive to changes in phosphine basicity. Bridging phosphine and carbonyl ligands are proposed for the transition state, and pairwise exchange of these ligands is favored. Activation parameters for PR{sub 3} = PEt{sub 3}, PEt{sub 2}Ph, and PMePh{sub 2} are {Delta}H{double dagger} = +16.8 to +17.3 kcal/mol and {Delta}S{double dagger} = {minus}17 to {minus}21 cal/mol K. Reactions of small phosphines (P(OMe){sub 3}, PMe{sub 3}, and PMe{sub 2}Ph) contain an additional term in the rate law due to phosphine substitution for CO in (PPN)(Fe{sub 2}Co(CO){sub 8}(PR{sub 3})(CCO)), which gives (PPN)(Fe{sub 2}Co(CO){sub 8}(PR{sub 3})(CPR{sub 3})). This reaction is in competition with ligand migration. Competition experiments and the observed steric barrier to substitution lead to the proposal that two phosphine ligands initially coordinate to the Co metal center and this is followed by a rapid intramolecular migration of one phosphine to the capping carbon atom. In the course of these mechanistic studies (PPN)(Fe{sub 2}Co(CO){sub 8}(PMe{sub 3})(CPMe{sub 3})) has been isolated and characterized.

  7. Alpha-monodeuterated benzyl alcohols and phosphobetaines from reactions of aromatic aldehydes with a water/D2O-soluble phosphine.

    PubMed

    Moiseev, Dmitry V; James, Brian R; Hu, Thomas Q

    2006-12-11

    With the aim of learning more about the bleaching action of pulps by (hydroxymethyl)phosphines, we reacted several benzaldehydes, containing MeO, Me, OH, or halogen substituents, with tris(3-hydroxypropyl)phosphine, [HO(CH2)3]3P, in aqueous solution at 90 degrees C under argon. Effective reduction of the aldehydes to the corresponding benzyl alcohols with concomitant oxidation of the phosphine to the phosphine oxide takes place, the reaction proceeding via an initially formed phosphonium species. When the reactions are carried out in D2O, the benzyl alcohol product from 3,4-dimethoxybenzaldehyde contains one deuterium atom at the benzyl-carbon atom, consistent with the last step of the mechanism involving a carbanion intermediate. With syringaldehyde (3,5-dimethoxy-4-hydroxy-benzaldehyde), the reduction product (syringyl alcohol) is more reactive toward the phosphine than is the starting aldehyde, and a zwitterionic, phosphobetaine product is formed. In D2O, the zwitterion benzyl protons and protons of the hydroxypropyl-CH2 adjacent to the P atom undergo H/D exchange via presumed phosphorus ylide intermediates. Under the same aqueous reaction conditions, tris(3-hydroxypropyl)phosphine, [HO(CH2)3]3P (THPP), does not undergo redox reactions with aliphatic aldehydes but simply promotes a base-catalyzed self-condensation (aldol) reaction. THPP reduction of an aromatic ketone is sluggish, presumably because the carbonyl C-atom is less electrophilic than that present in an aromatic aldehyde. PMID:17140243

  8. Unmasking the Action of Phosphinous Acid Ligands in Nitrile Hydration Reactions Catalyzed by Arene-Ruthenium(II) Complexes.

    PubMed

    Tomás-Mendivil, Eder; Cadierno, Victorio; Menéndez, María I; López, Ramón

    2015-11-16

    The catalytic hydration of benzonitrile and acetonitrile has been studied by employing different arene-ruthenium(II) complexes with phosphinous (PR2OH) and phosphorous acid (P(OR)2OH) ligands as catalysts. Marked differences in activity were found, depending on the nature of both the P-donor and η(6)-coordinated arene ligand. Faster transformations were always observed with the phosphinous acids. DFT computations unveiled the intriguing mechanism of acetonitrile hydration catalyzed by these arene-ruthenium(II) complexes. The process starts with attack on the nitrile carbon atom of the hydroxyl group of the P-donor ligand instead of on a solvent water molecule, as previously suggested. The experimental results presented herein for acetonitrile and benzonitrile hydration catalyzed by different arene-ruthenium(II) complexes could be rationalized in terms of such a mechanism. PMID:26448635

  9. Remote plasma enhanced chemical vapor deposition of GaP with in situ generation of phosphine precursors

    NASA Technical Reports Server (NTRS)

    Choi, S. W.; Lucovsky, G.; Bachmann, Klaus J.

    1993-01-01

    Thin homoepitaxial films of gallium phosphide (GaP) were grown by remote plasma enhanced chemical vapor deposition utilizing in situ generated phosphine precursors. The GaP forming reaction is kinetically controlled with an activation energy of 0.65 eV. The increase of the growth rate with increasing radio frequency (rf) power between 20 and 100 W is due to the combined effects of increasingly complete excitation and the spatial extension of the glow discharge toward the substrate, however, the saturation of the growth rate at even higher rf power indicates the saturation of the generation rate of phosphine precursors at this condition. Slight interdiffusion of P into Si and Si into GaP is indicated from GaP/Si heterostructures grown under similar conditions as the GaP homojunctions.

  10. Remote plasma enhanced chemical vapor deposition of GaP with in situ generation of phosphine precursors

    NASA Technical Reports Server (NTRS)

    Choi, S. W.; Lucovsky, G.; Bachmann, K. J.

    1992-01-01

    Thin homoepitaxial films of gallium phosphide (GaP) have been grown by remote plasma enhanced chemical vapor deposition utilizing in situ-generated phosphine precursors. The GaP forming reaction is kinetically controlled with an activation energy of 0.65 eV. The increase of the growth rate with increasing radio frequency (RF) power between 20 and 100 W is due to the combined effects of increasingly complete excitation and the spatial extension of the glow discharge toward the substrate; however, the saturation of the growth rate at even higher RF power indicates the saturation of the generation rate of phosphine precursors at this condition. Slight interdiffusion of P into Si and Si into GaP is indicated from GaP/Si heterostructures grown under similar conditions as the GaP homojunctions.

  11. Modular solid-phase synthesis, catalytic application and efficient recycling of supported phosphine-phosphite ligand libraries.

    PubMed

    Heutz, Frank J L; Kamer, Paul C J

    2016-02-01

    In spite of decades of research in the field of homogeneous asymmetric catalysis the discovery of new high performance catalysts still relies heavily on trial-and-error. There is still a lack of efficient combinatorial methods which enable the synthesis and screening of vast ligand libraries, especially for bidentate phosphorus ligands. Here we present a highly modular solid-phase synthetic approach which provides facile access to libraries of phosphine-phosphite ligands in quantitative yield requiring only minimal work-up. The obtained library of supported phosphine-phosphites was successfully applied in rhodium catalyzed asymmetric hydrogenation obtaining high enantioselectivities up to 98%. Also, these polymer supported ligands could be successfully recycled under batch conditions exhibiting only a small decline of activity and no loss of selectivity. PMID:26486695

  12. Antitumor Activity of Gold(I), Silver(I) and Copper(I) Complexes Containing Chiral Tertiary Phosphines

    PubMed Central

    McKeage, Mark J.; Papathanasiou, Peter; Sjaarda, Allan; Swiegers, Gerhard F.; Waring, Paul; Wild, S. Bruce

    1998-01-01

    The in vitro cytotoxicities of a number of gold(I), silver(I) and copper(I) complexes containing chiral tertiary phosphine ligands have been examined against the mouse tumour cell lines P815 mastocytoma, B16 melanoma [gold(I) and silver(I) compounds] and P388 leukaemia [gold(I) complexes only] with many of the complexes having IC50 values comparable to that of the reference compounds cis-diamminedichloroplatinum(ll), cisplatin, and bis[1,2-bis(diphenylphosphino) ethane]gold(I) iodide. The chiral tertiary phosphine ligands used in this study include (R)-(2-aminophenyl)methylphenylphosphine; (R,R)-, (S,S)- and (R*,R*)-1,2-phenylenebis(methylphenylphosphine); and (R,R)-, (S,S)- and (R*,R*)-bis{(2-diphenylphosphinoethyl)phenylphosphino}ethane. The in vitro cytotoxicities of gold(I) and silver(I) complexes containing the optically active forms of the tetra(tertiary phosphine) have also been examined against the human ovarian carcinoma cell lines 41M and CH1, and the cisplatin resistant 41McisR, CH1cisR and SKOV-3 tumour models. IC50 values in the range 0.01 - 0.04 μM were determined for the most active compounds, silver(I) complexes of the tetra(tertiary phosphine). Furthermore, the chirality of the ligand appeared to have little effect on the overall activity of the complexes: similar IC50 data were obtained for complexes of a particular metal ion with each of the stereoisomeric forms of a specific ligand. PMID:18475846

  13. A phosphinate-based near-infrared fluorescence probe for imaging the superoxide radical anion in vitro and in vivo.

    PubMed

    Zhang, Jianjian; Li, Chuwen; Zhang, Rui; Zhang, Fengyuan; Liu, Wei; Liu, Xiaoyan; Lee, Simon Ming-Yuen; Zhang, Haixia

    2016-02-01

    A novel near-infrared (NIR), turn-on fluorescence probe containing a phosphinate group as a recognizing moiety for the selective detection of O2˙(-) with a low limit of detection (LOD, 9.9 nM) was developed. has good cell-membrane permeability, intracellular stability, and low cytotoxicity. In addition, we successfully applied the to visualize O2˙(-) in live zebrafish, mouse and, for the first time, in mouse liver. PMID:26783733

  14. Hydrogenation of unactivated enamines to tertiary amines: rhodium complexes of fluorinated phosphines give marked improvements in catalytic activity

    PubMed Central

    Tin, Sergey; Fanjul, Tamara

    2015-01-01

    Summary In the hydrogenation of sluggish unactivated enamine substrates, Rh complexes of electron-deficient phosphines are demonstrated to be far more reactive catalysts than those derived from triphenylphosphine. These operate at low catalyst loadings (down to 0.01 mol %) and are able to reduce tetrasubstituted enamines. The use of the sustainable and environmentally benign solvent (R)-limonene for the reaction is also reported with the amine isolated by acid extraction. PMID:26124864

  15. ExoMol line lists - VII. The rotation-vibration spectrum of phosphine up to 1500 K

    NASA Astrophysics Data System (ADS)

    Sousa-Silva, Clara; Al-Refaie, Ahmed F.; Tennyson, Jonathan; Yurchenko, Sergei N.

    2015-01-01

    A comprehensive hot line list is calculated for 31PH3 in its ground electronic state. This line list, called SAlTY, contains almost 16.8 billion transitions between 7.5 million energy levels and it is suitable for simulating spectra up to temperatures of 1500 K. It covers wavelengths longer than 1 μm and includes all transitions to upper states with energies below hc × 18 000 cm-1 and rotational excitation up to J = 46. The line list is computed by variational solution of the Schrödinger equation for the rotation-vibration motion employing the nuclear-motion program TROVE. A previously reported ab initio dipole moment surface is used as well as an updated `spectroscopic' potential energy surface, obtained by refining an existing ab initio surface through least-squares fitting to the experimentally derived energies. Detailed comparisons with other available sources of phosphine transitions confirms SAlTY's accuracy and illustrates the incompleteness of previous experimental and theoretical compilations for temperatures above 300 K. Atmospheric models are expected to severely underestimate the abundance of phosphine in disequilibrium environments, and it is predicted that phosphine will be detectable in the upper troposphere of many substellar objects. This list is suitable for modelling atmospheres of many astrophysical environments, namely carbon stars, Y dwarfs, T dwarfs, hot Jupiters and Solar system gas giant planets. It is available in full from the Strasbourg data centre, CDS, and at www.exomol.com.

  16. Scalable noninjection phosphine-free synthesis and optical properties of tetragonal-phase CuInSe2 quantum dots.

    PubMed

    Liu, Feng; Zhu, Jun; Xu, Yafeng; Zhou, Li; Dai, Songyuan

    2016-05-21

    Phosphine-free synthesis of CISe quantum dots (QDs) is highly desirable, yet it has been challenging. The main difficulty lies in achieving phosphine-free Se precursors. Most reported protocols for the synthesis of size-confined CISe QDs highly depend on the use of air-sensitive, toxic, and expensive alkylphosphines to prepare reactive Se precursors and to confine particle growth. Herein, we present a new amine/thiol combination-based route to Se precursors that may enable a general synthesis of phosphine-free selenide QDs. What's more, instead of the traditional "hot-injection" method, we also report the first one-pot noninjection synthesis of high quality CISe QDs enabled by our strategy. A very high chemical yield of ∼95% is demonstrated, as well as the facile gram-scale production of monodisperse CISe QDs. By simply adjusting the amount of 1-dodecanethiol used in the synthesis, we are able to produce CISe QDs with continuous tunability of the particle size from ∼2 nm to ∼10 nm, and hence their intrinsic optical properties. PMID:27137673

  17. Palladium(II) complexes with tris(2-carboxyethyl)phosphine, structure, reactions and cytostatic activity.

    PubMed

    Pruchnik, Hanna; Lis, Tadeusz; Latocha, Małgorzata; Zielińska, Aleksandra; Pruchnik, Florian P

    2016-03-01

    Water soluble and air stable P(RCOOH)3 (R=C2H4) (TCEP) is an efficient reducing agent used in biochemistry to break S-S bond in peptides, proteins and other compounds containing S-S bonds. The similarity between the coordination chemistry of Pd(II) and Pt(II) led to the investigations of antitumor activity of palladium(II) compounds however the Pd(II) complexes with TCEP were not investigated. New palladium(II) complexes with (TCEP): trans-[PdCl2(TCEP)2] (1) and trans-[Pd2(μ-Cl)2Cl2(TCEP)2] (2) were fully characterized by (1)H, (13)C, (31)P NMR, IR and ESI-MS spectroscopic techniques. Complexes are stable in non-aqueous DMSO and DMF. In aqueous solutions Cl ligands are substituted by COO groups of phosphines. Complex 2, after crystallization from water gives polymeric compound with bridging phosphine ligand [PdCl{P(RCOO-κO-μ-O')(RCOOH)2-κP}] (3). Structures of trans-[PdCl2{P(RCOOD)3}2] (1a), trans-[Pd2(μ-Cl)2PdCl2{P(RCOOD)3}2] (2a), and [PdCl{P(RCOO-κO-μ-O')(RCOOD)2-κP}]n (3a) have been determined by X-ray crystallography. NMR and ESI-MS spectra reveal that [PdP2(RCOO-κO)2(RCOO)n(RCOOH)4-n](n)(-) complexes are formed in aqueous solution of 1. Geometry optimization in the gas phase at the B3LYP/3-21G** level indicated that complex 2 with butterfly structure is more stable than that with coplanar coordination. In aqueous solution of 2, the main products [Pd2{P(RCOO-κO-μ-O')(RCOO-κO)(RCOOH)}2] and [Pd{P(RCOO-κO)2(RCOOH)}(H2O)] exist in equilibrium which depends on temperature: content of mononuclear compound increases as the temperature is raised. Complexes 1 and 2 are active agents against melanoma and breast cancer cells. PMID:26710241

  18. Cationic Gold Clusters Ligated with Differently Substituted Phosphines: Effect of Substitution on Ligand Reactivity and Binding

    SciTech Connect

    Johnson, Grant E.; Olivares, Astrid M.; Hill, David E.; Laskin, Julia

    2015-01-01

    We present a systematic study of the effect of the number of methyl (Me) and cyclohexyl (Cy) functional groups in monodentate phosphine ligands on the solution-phase synthesis of ligated sub-nanometer gold clusters and their gas-phase fragmentation pathways. Small mixed ligand cationic gold clusters were synthesized using ligand exchange reactions between pre-formed triphenylphosphine ligated (PPh3) gold clusters and monodentate Me- and Cy-substituted ligands in solution and characterized using electrospray ionization mass spectrometry (ESI-MS) and collision-induced dissociation (CID) experiments. Under the same experimental conditions, larger gold-PPh3 clusters undergo efficient exchange of unsubstituted PPh3 ligands for singly Me- and Cy-substituted PPh2Me and PPh2Cy ligands. The efficiency of ligand exchange decreases with an increasing number of Me or Cy groups in the substituted phosphine ligands. CID experiments performed for a series of ligand-exchanged gold clusters indicate that loss of a neutral Me-substituted ligand is preferred over loss of a neutral PPh¬3 ligand while the opposite trend is observed for Cy-substituted ligands. The branching ratio of the competing ligand loss channels is strongly correlated with the electron donating ability of the phosphorous lone pair as determined by the relative proton affinity of the ligand. The results indicate that the relative ligand binding energies increase in the order PMe3 < PPhMe2 < PPh2Me < PPh3< PPh2Cy < PPhCy2< PCy3. Furthermore, the difference in relative ligand binding energies increases with the number of substituted PPh3-mMem or PPh3-mCym ligands (L) exchanged onto each cluster. This study provides the first experimental determination of the relative binding energies of ligated gold clusters containing differently substituted monophosphine ligands, which are important to controlling their synthesis and reactivity in solution. The results also indicate that ligand substitution is an important parameter that must be considered in theoretical modeling of these complex systems

  19. Competing C-F activation pathways in the reaction of Pt(0) with fluoropyridines: phosphine-assistance versus oxidative addition.

    PubMed

    Nova, Ainara; Erhardt, Stefan; Jasim, Naseralla A; Perutz, Robin N; Macgregor, Stuart A; McGrady, John E; Whitwood, Adrian C

    2008-11-19

    A survey of computed mechanisms for C-F bond activation at the 4-position of pentafluoropyridine by the model zero-valent bis-phosphine complex, [Pt(PH3)(PH2Me)], reveals three quite distinct pathways leading to square-planar Pt(II) products. Direct oxidative addition leads to cis-[Pt(F)(4-C5NF4)(PH3)(PH2Me)] via a conventional 3-center transition state. This process competes with two different phosphine-assisted mechanisms in which C-F activation involves fluorine transfer to a phosphorus center via novel 4-center transition states. The more accessible of the two phosphine-assisted processes involves concerted transfer of an alkyl group from phosphorus to the metal to give a platinum(alkyl)(fluorophosphine), trans-[Pt(Me)(4-C5NF4)(PH3)(PH2F)], analogues of which have been observed experimentally. The second phosphine-assisted pathway sees fluorine transfer to one of the phosphine ligands with formation of a metastable metallophosphorane intermediate from which either alkyl or fluorine transfer to the metal is possible. Both Pt-fluoride and Pt(alkyl)(fluorophosphine) products are therefore accessible via this route. Our calculations highlight the central role of metallophosphorane species, either as intermediates or transition states, in aromatic C-F bond activation. In addition, the similar computed barriers for all three processes suggest that Pt-fluoride species should be accessible. This is confirmed experimentally by the reaction of [Pt(PR3)2] species (R = isopropyl (iPr), cyclohexyl (Cy), and cyclopentyl (Cyp)) with 2,3,5-trifluoro-4-(trifluoromethyl)pyridine to give cis-[Pt(F){2-C5NHF2(CF3)}(PR3)2]. These species subsequently convert to the trans-isomers, either thermally or photochemically. The crystal structure of cis-[Pt(F){2-C5NHF2(CF3)}(P iPr3)2] shows planar coordination at Pt with r(F-Pt) = 2.029(3) A and P(1)-Pt-P(2) = 109.10(3) degrees. The crystal structure of trans-[Pt(F){2-C5NHF2(CF3)}(PCyp3)2] shows standard square-planar coordination at Pt with r(F-Pt) = 2.040(19) A. PMID:18950168

  20. Genetic characterization of field-evolved resistance to phosphine in the rusty grain beetle, Cryptolestes ferrugineus (Laemophloeidae: Coleoptera).

    PubMed

    Jagadeesan, Rajeswaran; Collins, Patrick J; Nayak, Manoj K; Schlipalius, David I; Ebert, Paul R

    2016-02-01

    Inheritance of resistance to phosphine fumigant was investigated in three field-collected strains of rusty grain beetle, Cryptolestes ferrugineus, Susceptible (S-strain), Weakly Resistant (Weak-R) and Strongly Resistant (Strong-R). The strains were purified for susceptibility, weak resistance and strong resistance to phosphine, respectively, to ensure homozygosity of resistance genotype. Crosses were established between S-strain×Weak-R, S-strain×Strong-R and Weak-R×Strong-R, and the dose mortality responses to phosphine of these strains and their F1, F2 and F1-backcross progeny were obtained. The fumigations were undertaken at 25°C and 55% RH for 72h. Weak-R and Strong-R showed resistance factors of 6.3× and 505× compared with S-strain at the LC50. Both weak and strong resistances were expressed as incompletely recessive with degrees of dominance of -0.48 and -0.43 at the LC50, respectively. Responses of F2 and F1-backcross progeny indicated the existence of one major gene in Weak-R, and at least two major genes in Strong-R, one of which was allelic with the major factor in Weak-R. Phenotypic variance analyses also estimated that the number of independently segregating genes conferring weak resistance was 1 (nE=0.89) whereas there were two genes controlling strong resistance (nE=1.2). The second gene, unique to Strong-R, interacted synergistically with the first gene to confer a very high level of resistance (~80×). Neither of the two major resistance genes was sex linked. Despite the similarity of the genetics of resistance to that previously observed in other pest species, a significant proportion (~15 to 30%) of F1 individuals survived at phosphine concentrations higher than predicted. Thus it is likely that additional dominant heritable factors, present in some individuals in the population, also influenced the resistance phenotype. Our results will help in understanding the process of selection for phosphine resistance in the field which will inform resistance management strategies. In addition, this information will provide a basis for the identification of the resistance genes. PMID:26821660

  1. A theoretical study of the mechanism of phosphine-catalyzed hydroalkoxylation of methyl vinyl ketone.

    PubMed

    Wang, Xin; Li, Shuhua; Jiang, Yuansheng

    2005-12-01

    The mechanism of phosphine-catalyzed hydroalkoxylation of the methyl vinyl ketone has been investigated by the second-order Møller-Plesset perturbation theory and the conductor-like polarized continuum model. The free energy reaction profiles of the reaction in both gas phase and solution phase are explored and compared. Our results suggest that the first stage of the studied reaction is the generation of the base (the methoxide anion) with the help of trialkylphosphine, and the second stage is the hydroalkoxylation of the methyl vinyl ketone catalyzed by this base. In the first stage, trialkylphosphine first adds to the methyl vinyl ketone to form a phosphonium enolate intermediate and then this species deprotonates a methanol molecule to generate a methoxide anion. Both steps involve free energy barriers of about 20 kcal/mol. In the second stage, both the addition of the methoxide anion to the methyl vinyl ketone and the proton transfer process from methanol to the methoxyl enolate anion intermediate have activation free energies of about 16 kcal/mol. The reaction in the second stage is exothermic by 10.2 kcal/mol at room temperature. A comparison of the free energy reaction profiles in the gas phase and the solution phase demonstrated that the generation of the methoxide anion could only occur in the presence of the polar solvents. The mechanism proposed in the present work is in reasonable agreement with the known experimental facts. PMID:16863126

  2. Catalytic Oxidation of Alcohol via Nickel Phosphine Complexes with Pendant Amines

    SciTech Connect

    Weiss, Charles J.; Das, Partha Pratim; Higgins, Deanna LM; Helm, Monte L.; Appel, Aaron M.

    2014-09-05

    Nickel complexes were prepared with diphosphine ligands that contain pendant amines, and these complexes catalytically oxidize primary and secondary alcohols to their respective aldehydes and ketones. Kinetic and mechanistic studies of these prospective electrocatalysts were performed to understand what influences the catalytic activity. For the oxidation of diphenylmethanol, the catalytic rates were determined to be dependent on the concentration of both the catalyst and the alcohol. The catalytic rates were found to be independent of the concentration of base and oxidant. The incorporation of pendant amines to the phosphine ligand results in substantial increases in the rate of alcohol oxidation with more electron-donating substituents on the pendant amine exhibiting the fastest rates. We thank Dr. John C. Linehan, Dr. Elliott B. Hulley, Dr. Jonathan M. Darmon, and Dr. Elizabeth L. Tyson for helpful discussions. Research by CJW, PD, DLM, and AMA was supported by the US Department of Energy, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences & Biosciences. Research by MLH was supported as part of the Center for Molecular Electrocatalysis, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences. Pacific Northwest National Laboratory (PNNL) is a multiprogram national laboratory operated for DOE by Battelle.

  3. Zirconium extraction into octyl(phenyl)-N,N-diisobutylcarbamoylmethyl phosphine oxide and tributyl phosphate

    SciTech Connect

    Brewer, K.N.; Herbst, R.S.; Todd, T.A.; Christian, J.D.

    1998-07-01

    Classical slope analysis techniques were used to determine the octyl(phenyl)-N,N-diisobutylcarbamoylmethyl phosphine oxide (CMPO) and nitrate stoichiometries for the extraction of zirconium by CMPO diluted with diisopropylbenzene (DIPB). The equilibrium constant for the extraction of zirconium by CMPO was also determined using classical slope analysis techniques. The extraction of zirconium by TBP in n-dodecane was used as a control to verify the zirconium species as Zr{sup +4}, and to verify the experimental methodology. Equilibrium [CMPO]{sub org} and [TBP]{sub org} concentrations were determined by accounting for the extraction of HNO{sub 3} into both TBP and CMPO solvents. Nitric acid dissociation and aqueous phase activity coefficients were also taken into consideration. Organic activity coefficients, Zr{sup +4} activity coefficients, Zr{sup +4} hydrolysis, and consumption of TBP or CMPO by water were neglected. Nitrate and CMPO dependencies for the extraction of zirconium have been determined from this work to be: Zr{sub aq}{sup +4} + 4 NO{sub 3 aq}{sup {minus}} + 2 CMPO{sub org} {r_arrow} Zr(NO{sub 3}){sub 4} {sm_bullet} 2 CMPO{sub org}. An equilibrium constant of 1.13 {times} 10{sup 5} {+-} 1.48 {times} 10{sup 4} at 25 C was also determined for this reaction.

  4. A computational study: reactivity difference between phosphine- and amine-catalyzed cycloadditions of allenoates and enones.

    PubMed

    Huang, Gou-Tao; Lankau, Timm; Yu, Chin-Hui

    2014-02-21

    Allenoates and enones form cyclopentenes via a phosphine-catalyzed [3 + 2] cycloaddition while the amine-catalyzed [2 + 4] cycloaddition yields dihydropyrans or pyrans. The difference between these catalysts is studied with M06-2X/6-31+G* calculations. The addition of the catalyst to the allenoate is the first step in both pathways followed by the reaction with the enone. The formation of the [3 + 2] phosphorus-ylide is exergonic, and hence, the [3 + 2] cycloaddition is kinetically favored over the [2 + 4] addition. Amines do not stabilize [3 + 2] ammonium-ylides. However, electron-withdrawing groups on the enone enable [2 + 4] cycloadditions. The strength of the electron-withdrawing group further controls the α/γ regioselectivity of the [2 + 4] cycloaddition, and the analysis of the HOMO-LUMO interactions explains why only E-dihydropyrans from the direct γ-[2 + 4] cycloaddition have been observed in experiments. The quantum calculations further reveal a new path to the α-[2 + 4] product starting with an intermediate Rauhut-Currier reaction. This new path is kinetically favored over the direct amine-catalyzed α-[2 + 4] cycloaddition. PMID:24437625

  5. Gas phase ion chemistry and ab initio theoretical study of phosphine. I

    NASA Astrophysics Data System (ADS)

    Antoniotti, Paola; Operti, Lorenza; Rabezzana, Roberto; Splendore, Maurizio; Tonachini, Glauco; Vaglio, Gian Angelo

    1997-08-01

    Gas phase ion processes of phosphine have been studied by theoretical calculations and experimental techniques. Ab initio quantum chemical calculations have been performed on the ion/molecule reactions starting from P+ in PH3, as they have been observed by ion trapping. P+ gives P2Hn+ (n=1,2) product ions with loss of H2 or H in different pathways and also reacts in charge-exchange processes to form PH3+. The energies of transition structures, reaction intermediates, and final products, as well as their geometrical structures have been determined by theoretical methods. The initial step is formation of a triplet P2H3+ adduct of C3v symmetry (P-PH3+). A hydrogen atom can either be directly lost from the tetracoordinated phosphorus, or first undergo a shift to the other P atom (HP+-PH2), followed by P-H bond dissociation. Dissociation of H2 from P2H3+ can also occur from both the initial P-PH3+ and HP+-PH2 species yielding PPH+. The heats of formation of the P2Hn+ ionic species have also been computed and compared with experimental data reported in the literature.

  6. Doping limits of grown in situ doped silicon nanowires using phosphine.

    PubMed

    Schmid, Heinz; Björk, Mikael T; Knoch, Joachim; Karg, Siegfried; Riel, Heike; Riess, Walter

    2009-01-01

    Structural characterization and electrical measurements of silicon nanowires (SiNWs) synthesized by Au catalyzed vapor-liquid-solid growth using silane and axially doped in situ with phosphine are reported. We demonstrate that highly n-doped SiNWs can be grown without structural defects and high selectivity and find that addition of the dopant reduces the growth rate by less than 8% irrespective of the radius. This indicates that also the dopant incorporation is radius-independent. On the basis of electrical measurements on individual wires, contact resistivities as low as 1.2 x 10(-7) omega cm(-2) were extracted. Resistivity measurements reveal a reproducible donor incorporation of up to 1.5 x 1020 cm-3 using a gas phase ratios of Si/P = 1.5 x 10(-2). Higher dopant gas concentrations did not lead to an increase of the doping concentration beyond 1.5 x10(20) cm(-3). PMID:19099512

  7. Phosphine Oxide Based Electron Transporting and Hole Blocking Materials for Blue Electrophosphorescent Organic Light Emitting Devices

    SciTech Connect

    Von Ruden, Amber L.; Cosimbescu, Lelia; Polikarpov, Evgueni; Koech, Phillip K.; Swensen, James S.; Wang, Liang; Darsell, Jens T.; Padmaperuma, Asanga B.

    2010-10-26

    We report the design, synthesis, thermal, and photophysical properties of two phosphine oxide based electron transport/hole blocking materials, 2,6-bis(4-(diphenylphosphoryl)phenyl)pyridine (BM-A11) and 2,4-bis(4-(diphenyl-phosphoryl)phenyl)pyridine (BM-A10) for blue electrophosphorescent organic light emitting devices (OLEDs). The use of these materials in blue OLED with iridium (III) bis[(4,6-difluorophenyl)-pyridinato-N,C2’]picolinate (Firpic) as the phosphor was demonstrated. Using the dual host device architecture with BM-A10 as the ETM yields a maximum EQE of 8.9% with a power efficiency of 21.5 lm/W (4.0V and 35 cd/m2). When BM-A11 is used as the ETM, the maximum EQE and power efficiency improves to 14.9% and 48.4 lm/W, respectively (3.0V and 40 cd/m2).

  8. A photoionization mass spectroscopic study on the formation of phosphanes in low temperature phosphine ices.

    PubMed

    Turner, Andrew M; Abplanalp, Matthew J; Chen, Si Y; Chen, Yu T; Chang, Agnes H H; Kaiser, Ralf I

    2015-11-01

    Isovalency rationalizes fundamental chemical properties of elements in the same group, but often fails to account for differences in the molecular structure due to the distinct atomic sizes and electron-pair repulsion of the isovalent atoms. With respect to main group V, saturated hydrides of nitrogen are limited to ammonia (NH3) and hydrazine (N2H4) along with ionic and/or metal-bound triazene (N3H5) and potentially tetrazene (N4H6). Here, we present a novel approach for synthesizing and detecting phosphanes formed via non-classical synthesis exploiting irradiation of phosphine ices with energetic electrons, subliming the newly formed phosphanes via fractionated sublimation, and detecting these species via reflectron time-of-flight mass spectrometry (ReTOF) coupled with vacuum ultraviolet (VUV) single photon ionization. This approach is able to synthesize, to separate, and to detect phosphanes as large as octaphosphane (P8H10), which far out-performs the traditional analytical tools of infrared spectroscopy and residual gas analysis via mass spectrometry coupled with electron impact ionization that could barely detect triphosphane (P3H5) thus providing an unconventional tool to prepare complex inorganic compounds such as a homologues series of phosphanes, which are difficult to synthesize via classical synthetic methods. PMID:26242769

  9. New insights into steric and electronic effects in a series of phosphine ligands from the perspective of local quantum similarity using the Fukui function.

    PubMed

    Morales-Bayuelo, Alejandro; Caballero, Julio

    2015-03-01

    The field of molecular quantum similarity (MQS) was introduced by Carb-Dorca 30 years ago. MQS currently suffers from numerous bottlenecks, for example when studying similarities in chemical reactivity, because there is no clear guidance on the best methodology to follow. For this reason, we have revisited this topic here. Today's search tools and methodologies have made an important contribution to studying steric and electronic effects in phosphine ligands (PR3). In this contribution, we propose a hybrid methodology joining (MQS) and chemical reactivity. Additionally, a chemical reactivity study using global and local reactivity descriptors was performed in the context of density functional theory (DFT). Phosphines are ?-donor and ?-acceptor ligands, therefore reactivity descriptors allow us quantify the retrodonor process in terms of quantum similarity (QS). In this regard, new ways to characterize steric and electronic effects in phosphine ligands and their chemical bonds are presented in the QS context. PMID:25687904

  10. Air-stable platinum and palladium complexes featuring bis[2,4-bis(trifluoromethyl)phenyl]phosphinous acid ligands.

    PubMed

    Kurscheid, Boris; Neumann, Beate; Stammler, Hans-Georg; Hoge, Berthold

    2011-12-23

    Secondary phosphane oxides, R(2)P(O)H, are commonly used as preligands for transition-metal complexes of phosphinous acids, R(2)P-OH (R=alkyl, aryl), which are relevant as efficient catalysts in cross-coupling processes. In contrast to previous work by other groups, we are interested in the ligating properties of an electron-deficient phosphinous acid, (R(f))(2)P-OH, bearing the strongly electron-withdrawing and sterically demanding 2,4-bis(trifluoromethyl)phenyl group towards catalysis-relevant metals, such as palladium and platinum. The preligand bis[2,4-bis(trifluoromethyl)phenyl]phosphane oxide, (R(f))(2)P(O)H, reacts smoothly with solid platinum(II) dichloride yielding the trans-configured phosphinous acid platinum complex trans-[PtCl(2)({2,4-(CF(3))(2)C(6)H(3)}(2)POH)(2)]. The deprotonation of one phosphinous acid ligand with an appropriate base leads to the cis-configured monoanion complex cis-[PtCl(2)({2,4-(CF(3))(2)C(6)H(3)}(2)PO)(2)H](-), featuring the quasi-chelating phosphinous acid phosphinito unit, (R(f))(2)P-O-H···O=P(R(f))(2), which exhibits a strong hydrogen bridge substantiated by an O···O distance of 245.1(4) pm. The second deprotonation step is accompanied by a rearrangement to afford the trans-configured dianion trans-[PtCl(2)({2,4-(CF(3))(2)C(6)H(3)}(2)PO)(2)](2-). The reaction of (R(f))(2)P(O)H with solid palladium(II) dichloride initially yields a mononuclear palladium complex [PdCl(2)({2,4-(CF(3))(2)C(6)H(3)}(2)POH)(2)], which condenses under liberation of HCl to the neutral dinuclear palladium complex [Pd(2)(μ-Cl)(2){({2,4-(CF(3))(2)C(6)H(3)}(2)PO)(2)H}(2)]. The equilibrium between the mononuclear [PdCl(2)({2,4-(CF(3))(2)C(6)H(3)}(2)POH)(2)] and dinuclear [Pd(2)(μ-Cl)(2){({2,4-(CF(3))(2)C(6)H(3)}(2)PO)(2)H}(2)] palladium complexes is reversible and can be shifted in each direction by the addition of base or HCl, respectively. Treatment of palladium(II) hexafluoroacetylacetonate, [Pd(F(6)acac)(2)], with a slight excess of (R(f))(2)P(O)H yields the complex [Pd(F(6)acac)({2,4-(CF(3))(2)C(6)H(3)}(2)PO)(2)H]. The quasi-chelating phosphinous acid phosphinito unit, which is formed by the liberation of HF(6)acac, is characterized by a O···O distance of 244.1(3) pm. These transition metal complexes are stable towards air and moisture and can be stored for months without any evidence of decomposition. PMID:22147659

  11. Experimental and Computational Studies of the Isomerization Reactions of Bidentate Phosphine Ligands in Triosmium Clusters

    SciTech Connect

    Xue, Zhang; Kandala, Srikanth; Yang, Li; Watson, William H.; Wang, Xiaoping; Hrovat, David A.

    2011-01-01

    The diphosphine ligand 1,2-bis(diphenylphosphino)benzene (dppbz) reacts with the activated cluster 1,2-Os{sub 3}(CO){sub 10}(MeCN){sub 2} (1) at room temperature to furnish a mixture of the triosmium clusters 1,2-Os{sub 3}(CO){sub 10}(dppbz) (2) and 1,1-Os{sub 3}(CO){sub 10}(dppbz) (3), along with a trace amount of the hydride cluster HOs{sub 3}(CO){sub 9}[{mu}-1,2-PhP(C{sub 6}H{sub 4}-{eta}{sup 1})C{sub 6}H{sub 4}PPh{sub 2}] (4). The dppbz-bridged cluster 2 forms as the kinetically controlled product and irreversibly transforms to the corresponding chelated isomer 3 at ambient temperature. The disposition of the dppbz ligand in 2 and 3 has been established by X-ray crystallography and {sup 31}P NMR spectroscopy, and the kinetics for the conversion 2 {yields} 3 have been followed by UV-vis spectroscopy in toluene over the temperature range 318-343 K. The calculated activation parameters ({Delta}H{sub {+-}} = 21.6(3) kcal/mol; {Delta}S{sub {+-}} = -11(1) eu) and lack of CO inhibition support an intramolecular isomerization mechanism that involves the simultaneous migration of phosphine and CO groups about the cluster polyhedron. The reaction between 1 and the fluorinated diphosphine ligand 1,2-bis(diphenylphosphino)tetrafluorobenzene (dppbzF{sub 4}) was examined under similar reaction conditions and was found to afford the chelated cluster 1,1-Os{sub 3}(CO){sub 10}(dppbzF{sub 4}) (6) as the sole observable product. The absence of the expected bridged isomer 1,2-Os{sub 3}(CO){sub 10}(dppbzF{sub 4}) (5) suggests that the dppbzF{sub 4} ligand destabilizes 5, thus accounting for the rapid isomerization of 5 to 6. Near-UV irradiation of clusters 3 and 6 leads to CO loss and ortho metalation of an ancillary aryl group. The resulting hydride clusters 4 and HOs{sub 3}(CO){sub 9}[{mu}-1,2-PhP(C{sub 6}H{sub 4}-{eta}{sup 1})C{sub 6}F{sub 4}PPh{sub 2}] (7) have been isolated and fully characterized by spectroscopic and X-ray diffraction analyses. Both 4 and 7 react with added CO under mild conditions to regenerate 3 and 6, respectively, in quantitative yield. The rearrangements of bridged to chelated diphosphine complexes in this genre of decacarbonyl clusters have been investigated by DFT calculations. The computational results support a concerted process, involving the scrambling of equatorial CO and phosphine groups via a classical merry-go-round exchange scheme. The barriers computed for this mechanism agree well with those that have been measured, and steric compression within the bridged diphosphine groups of the reactants has been calculated to reduce the barrier heights for the rearrangement.

  12. Transition Metal Complexes of Phosphinous Acids Featuring a Quasichelating Unit: Synthesis, Characterization, and Hetero-bimetallic Complexes.

    PubMed

    Allefeld, Nadine; Bader, Julia; Neumann, Beate; Stammler, Hans-Georg; Ignat'ev, Nikolai; Hoge, Berthold

    2015-08-17

    Diorganophosphane oxides were employed as preligands for the synthesis of catalytically active transition metal complexes of the phosphinous acids (CF3)2POH and (C2F5)2POH. Their reactions with solid PtCl2 and PdCl2 led to the formation of mononuclear phosphinous acid complexes [Cl2M{P(R(f))2OH}2] (M = Pd, Pt; R(f) = C2F5, CF3), which can be crystallized, for example, as its pyridinium salts, 2[HPy](+)[Cl2Pd{P(CF3)2O}2](2-). In vacuo HCl is liberated from the neutral palladium complexes affording mixtures of di- and polynuclear complexes. Moreover, (C2F5)2POH was reacted with several β-diketonato complexes of palladium, platinum, and nickel yielding air- and moisture-stable complexes [(acac)M{[P(R(f))2O]2H}], featuring a quasichelating phosphinous acid phosphinito unit {P(R(f))2O···H···O(R(f))2P}(-). Treatment of [Ni(Cp)2] (Cp = cyclopentadienyl) and [(cod)RhCl]2 (cod = 1,5-cyclooctadiene) with (C2F5)2POH leads to the substitution of one Cp or chloro ligand by a quasichelating unit. The novel coordination compounds were characterized by NMR and IR spectroscopies, mass spectrometry, and X-ray diffraction analysis. The platinum complex [(acac)Pt{[P(C2F5)2O]2H}] (acac = acetylacetonato) was used for the construction of hetero-bimetallic complexes by the treatment with [(cod)RhCl]2 and [Ni(Cp)2]. The trinuclear bimetallic complex [{(acac)Pt[P(C2F5)2O]2}2Ni] is the first structurally characterized hetero-bimetallic species containing a bis(perfluoroalkyl)phosphinito bridge. PMID:26242286

  13. Evidence for a SN2-type pathway in the exchange of phosphines at a [PhSe]+ centre.

    PubMed

    Forfar, Laura C; Green, Michael; Haddow, Mairi F; Hussein, Sharifa; Lynam, Jason M; Slattery, John M; Russell, Christopher A

    2015-01-01

    A range of thio- and seleno-phosphonium cationic complexes [RE(PR'3)](+)[X](-) (R = Me, Ph; E = S, Se; X = GaCl4, SbF6) have been synthesised and structurally characterised. Reaction of [PhSPPh3][GaCl4] and [PhSePPh3][GaCl4] with P(t)Bu3 results in the ready transfer of the "RS(+)" and "RSe(+)" fragments from PPh3 to the stronger electron donor P(t)Bu3. NMR experiments combined with an Eyring analysis on the corresponding degenerate phosphine exchange reaction allowed the thermodynamic values for the phosphine exchange reaction of the sulfur cation (ΔH(‡) 18.7 ± 12.0 kJ mol(-1); ΔS(‡) -99.3 ± 36.3 J mol(-1) K(-1)) to be compared with the corresponding values (ΔH(‡) 2.4 ± 1.1 kJ mol(-1) and ΔS(‡) -58.1 ± 5.0 J mol(-1) K(-1)) for the [PhSePPh3](+) system. Importantly, the large negative entropy of activation and linear dependence on the rate of exchange are compatible with an SN2-type exchange process. This conclusion is supported by DFT calculations which confirm that the phosphine exchange process occurs via an associative mechanism. The rate of exchange was found to increase from sulfur to selenium and those with aryl substituents underwent exchange faster than those with alkyl substituents. PMID:25318556

  14. Phosphine and methylphosphine production by simulated lightning—a study for the volatile phosphorus cycle and cloud formation in the earth atmosphere

    NASA Astrophysics Data System (ADS)

    Glindemann, Dietmar; Edwards, Marc; Schrems, Otto

    Phosphine (PH 3), was recently found worldwide even in the remote atmosphere (Naturwissenschaften83(1996a)131; Atmos. Environ. 37(2003)24 29). It is of interest to find natural mechanisms which could produce phosphine gas and drive a volatile link of the atmospheric phosphorus cycle and the formation of phosphoric acid as possible condensation nuclei for clouds. Here, we report on simulated lightning exposing sodium phosphate in a reducing medium (methane model atmosphere or organic matter) for 5 s to a spark induced by microwave. The gas product analyzed by gas chromatography contained phosphine (yield up to 0.6 g kg -1 phosphate P) and methylphosphine (CH 3)PH 2 (yield up to 0.02 g kg -1 phosphate P). We suggest a plasma-chemical formation mechanism where organic compounds or methane or secondary hydrogen thereof reduce phosphate to phosphine of which a small fraction can subsequently react with methyl radicals to form methylphosphine. A small yield of 6 mg phosphine per kg phosphate P was even obtained in methane free medium, by simple plasmatic recombination of inorganic phosphorus. We believe that methane and hydrogen are useful model substances of pyrolytic gases with high reducing power which may form if lightning strikes biomass, soil and aerosol. These results suggest evidence that phosphine and methylphosphine (detectable in the field by intense garlic odor) are produced when atmospheric lightning strikes the ground or aerosol which is containing oxidized forms of phosphorus and chemical reductants. Additional reviewed data show that laboratory lightning was able to reduce a much more significant portion of phosphate to phosphite (up to 25% yield), methylphosphonic acid (up to 8.5% yield) and traces of hypophosphite in a matter of seconds.

  15. Susceptibility of Two Strains of the Confused Flour Beetle (Coleoptera: Tenebrionidae) Following Phosphine Structural Mill Fumigation: Effects of Concentration, Temperature, and Flour Deposits.

    PubMed

    Aulicky, R; Stejskal, V; Frydova, B; Athanassiou, C G

    2015-12-01

    In this study, we evaluated phosphine efficacy against two strains of the confused flour beetle, Tribolium confusum Jacquelin du Val (Coleoptera: Tenebrionidae), one laboratory strain, with no previous exposure to phosphine, and one field strain, originated from the flour mill on which we performed the fumigation. The standard Detia Degesh Phosphine Resistance Kit showed that the adults of the field strain of T. confusum required 4.4 × longer time to be knocked down than the laboratory strain. In order to assess the efficacy of phosphine in the field against these strains, aluminium phosphide (AlP) was applied in a flour mill in Czech Republic, in 2014. In this application, temperature among the six floors of the flour mill varied between 20 and 30°C, relative humidity (RH) between 44 and 78%, and phosphine concentration-time-products (CtP) between 24 and 38 g.m(-3).h(-1). Moreover, the insects were bioassayed in dishes that contained either no commodity or 1, 3, and 5 cm of flour. Nevertheless, despite these variations, all adults and larvae from both strains were dead, regardless of the floor, the quantity of the commodity, and the conditions prevailing. However, larval emergence from eggs that were used in the bioassays for both strains was recorded in some of the locations tested. In addition, larval emergence was negatively correlated with both temperature and RH. At the same time, emergence was generally similar between strains. The results of the present study illustrate that highly visible dead adults and larvae after the application of phosphine falsely imply good fumigation efficacy, given that a considerable number of eggs are very likely to survive in a wider range of conditions, and the concomitant larval emergence may result in rapid population grown right after the fumigation. PMID:26454878

  16. Transcriptional inhibition of the Catalase gene in phosphine-induced oxidative stress in Drosophila melanogaster.

    PubMed

    Liu, Tao; Li, Li; Zhang, Fanhua; Wang, Yuejin

    2015-10-01

    Phosphine (PH3) is a toxic substance to pest insects and is therefore commonly used in pest control. The oxidative damage induced by PH3 is considered to be one of the primary mechanisms of its toxicity in pest insects; however, the precise mode of PH3 action in this process is still unclear. In this study, we evaluated the responses of several oxidative biomarkers and two of the main antioxidant enzymes, catalase (CAT) and superoxide dismutase (SOD), after fumigation treatment with PH3 in Drosophila melanogaster as a model system. The results showed that larvae exposed to sub-lethal levels of PH3 (0.028 mg/L) exhibited lower aerobic respiration rates and higher levels of hydrogen peroxide (H2O2) and lipid peroxidation (LPO). Furthermore, unlike SOD, the activity and expression of CAT and its encoding gene were downregulated by PH3 in a time- and dose-dependent manner. Finally, the responses of six potential transcription factors of PH3 were determined by real-time polymerase chain reaction to explore the regulation mechanism of DmCAT by PH3. There were no significant effects of PH3 on three nuclear factor-kappa B homologs (DORSAL, DIF, and RELISH) or two activator protein-1 genes (JUN and FOS), while dramatic inhibition of DNA replication-related element factor (DREF) expression was observed after fumigation with PH3, suggesting that PH3 could inhibit the expression of DmCAT via the DRE/DREF system. These results confirmed that PH3 induces oxidative stress and targets CAT by downregulating its encoding gene in Drosophila. Our results provide new insight into the signal transduction mechanism between PH3 and its target genes. PMID:26453223

  17. Ambipolar Phosphine Derivatives to Attain True Blue OLEDs with 6.5% EQE.

    PubMed

    Kondrasenko, Ilya; Tsai, Zheng-Hua; Chung, Kun-You; Chen, Yi-Ting; Ershova, Yana Yu; Doménech-Carbó, Antonio; Hung, Wen-Yi; Chou, Pi-Tai; Karttunen, Antti J; Koshevoy, Igor O

    2016-05-01

    A family of new branched phosphine derivatives {Ph2N-(C6H4)n-}3P → E (E = O 1-3, n = 1-3; E = S 4-6, n = 1-3; E = Se 7-9, n = 1-3; E = AuC6F5 4-6, n = 1-3), which are the donor-acceptor type molecules, exhibit efficient deep blue room temperature fluorescence (λem = 403-483 nm in CH2Cl2 solution, λem = 400-469 nm in the solid state). Fine tuning the emission characteristics can be achieved varying the length of aromatic oligophenylene bridge -(C6H4)n-. The pyramidal geometry of central R3P → E fragment on the one hand disrupts π-conjugation between the branches to preserve blue luminescence and high triplet energy, while on the other hand provides amorphous materials to prevent excimer formation and fluorescence self-quenching. Hence, compounds 2, 3, 5, and 12 were used as emitters to fabricate nondoped and doped electroluminescent devices. The luminophore 2 (E = O, n = 2) demonstrates excellently balanced bipolar charge transport and good nondoped device performance with a maximum external quantum efficiency (EQEmax) of 3.3% at 250 cd/m(2) and Commission International de L'Eclairage (CIE) coordinates of (0.15, 0.08). The doped device of 3 (E = O, n = 3) shows higher efficiency (EQEmax of 6.5, 6.0 at 100 cd/m(2)) and high color purity with CIE (0.15, 0.06) that matches the HDTV standard blue. The time-resolved electroluminescence measurement indicates that high efficiency of the device can be attributed to the triplet-triplet annihilation to enhance generation of singlet excitons. PMID:27100797

  18. Ammonia, Phosphine, And Cloud Structure On Saturn Derived From 5-micron Spectra

    NASA Astrophysics Data System (ADS)

    Bjoraker, Gordon; Chanover, N.; Glenar, D.; Hewagama, T.

    2006-09-01

    The CSHELL spectrometer on NASA's Infrared Telescope Facility was used to observe Saturn at several settings between 5.07 and 5.27μm beginning in 2004 February through 2006 January at about the same time as Cassini/VIMS and CIRS were mapping the planet. At these wavelengths thermal radiation originates from the deep atmosphere (5 bars) and it is attenuated by two cloud layers considered to be composed of NH4SH and condensed NH3. In addition, there is a component of sunlight reflected from the upper (NH3) cloud that varies spatially on Saturn. CSHELL can spectrally resolve profiles of absorption lines of ammonia (NH3) and phosphine (PH3) on Saturn. These lines are very broad due to collisions with 3 to 5 bars of hydrogen. The Saturn spectrum exhibits several strong NH3 and PH3 lines, as well as Fraunhofer lines due to CO in the Sun. The spatial variation of this spectrum is dominated by the variable opacity of Saturn's cloud structure. Superimposed on this are smaller variations in the mixing ratios of NH3 and PH3. The abundances of these gases can be retrieved reliably in relatively cloud-free regions between 50 South and 65 South, which are analogous to Jupiter's belts and 5-micron hot spots. Elsewhere, it is more difficult to separate changes in cloud opacity from gas abundances. We use near-simultaneous CIRS observations which sound the 500-mbar level to provide an upper boundary condition to PH3. The 5-μm spectrum of Saturn's Equatorial Zone (10 South) is significantly different from a region near 60 South. The NH3 and PH3 lines are weaker and narrower in the EQZ, while the Fraunhofer lines are stronger. We will present synthetic spectra calculated from models which fit both regions and which explore the tradeoffs between gas mixing ratios and cloud opacity. This work was supported by NASA's Planetary Astronomy program.

  19. Evaluation of headspace solid-phase microextraction for analysis of phosphine residues in wheat.

    PubMed

    Ren, Yong Lin; Padovan, Benjamin; Desmarchelier, James M

    2012-01-01

    In headspace (HS) analysis, a fumigant is released from a commodity into a gas-tight container by grinding, heating, or microwaves. A new technique uses HS-solid-phase microextraction (SPME) for additional preconcentration of fumigant. HS-SPME was tested for detection of phosphine (PH3), chosen for examination because of its wide use on stored commodities. PH3 was applied to 50 g wheat in separate 250 mL sealed flasks, which were equipped either with a septum for conventional HS analysis or with one of four HS-SPME fibers [100 microm polydimethylsiloxane (PDMS), 85 microm carboxen (CAR)/PDMS, 75 microm CAR/PDMS, and 65 pm PDMS/divinylbenzene (DVB)]. The wheat was heated at 45 degrees C for 20 min. In conventional HS analysis, a gaseous aliquot (80 pL) was taken from the HS and injected into the GC instrument. In the HS-SPME procedure, the fiber was removed from the HS and exposed in the heated injection port of the GC instrument. In all cases, PH3 was determined under the same chromatographic conditions with a GC pulsed flame photometric detector. In a comparison of the efficacy of the fibers, the bipolar fibers (CAR/PDMS and PDMS/DVB) contained more PH3 than the aliquot in the conventional HS analysis; larger size bipolar fibers extracted PH3 more efficiently than smaller fibers (e.g., 85 > 75 > 65 microm). The nonpolar fiber (PDMS) contained no PH3. Four fortification levels of PH3 on wheat were tested: 0.01, 0.05, 0.1, and 0.3 microg/g. The response of each bipolar fiber increased with the fortification levels, but the conventional HS analysis detected no fumigant at the lowest fortification level of 0.01 mg/g. Under the conditions of the validation study, the LOD was in the range of 0.005-0.01 ng PH3/g wheat. PMID:22649943

  20. Impedance technology reveals correlations between cytotoxicity and lipophilicity of mono and bimetallic phosphine complexes.

    PubMed

    Fonteh, P; Elkhadir, A; Omondi, B; Guzei, I; Darkwa, J; Meyer, D

    2015-08-01

    Label free impedance technology enables the monitoring of cell response patterns post treatment with drugs or other chemicals. Using this technology, a correlation between the lipophilicity of metal complexes and the degree of cytotoxicity was observed. Au(L1)Cl (1), AuPd(L1)(SC4H8)Cl3 (1a) and Au(L2)Cl (2) [L1 = diphenylphosphino-2-pyridine; L2 = 2-(2-(diphenylphosphino)ethyl)-pyridine] were synthesised, in silico drug-likeness and structure-activity relationship monitored using impedance technology. Dose dependent changes in cytotoxicity were observed for the metal complexes resulting in IC50s of 12.5 ± 2.5, 18.3 ± 8.3 and 16.9 ± 0.5 µM for 1, 1a and 2 respectively in an endpoint assay. When a real time impedance assay was used, dose-dependent responses depicting patterns that suggested slower uptake (at a toxic 20 µM) and faster recovery of the cells (at the less toxic 10 µM) of the bimetallic complex (1a) compared to the monometallic complexes (1 and 2) was observed. These data agreed with the ADMET findings of lower aqueous solubility of 1a and non-ideal lipophilicity (AlogP98 of 6.55) over more water soluble 1 and 2 with ideal lipophilicity (4.91 and 5.03 respectively) values. The additional coordination of a Pd atom to the nitrogen atom of a pyridine ring, the sulfur atom of a tetrahydrothiophene moiety and two chlorine atoms in 1a could be contributing to the observed differences when compared to the monometallic complexes. This report presents impedance technology as a means of correlating drug-likeness of lipophilic phosphine complexes containing similar backbone structures and could prove valuable in filtering drug-like compounds in a drug discovery project. PMID:25829148

  1. Apparatus for purifying arsine, phosphine, ammonia, and inert gases to remove Lewis acid and oxidant impurities therefrom

    DOEpatents

    Tom, Glenn M.; Brown, Duncan W.

    1991-01-08

    An apparatus for purifying a gaseous mixture comprising arsine, phosphine, ammonia, and/or inert gases, to remove Lewis acid and/or oxidant impurities therefrom, comprising a vessel containing a bed of a scavenger, the scavenger including a support having associated therewith an anion which is effective to remove such impurities, such anion being selected from one or more members of the group consisting of: (i) carbanions whose corresponding protonated compounds have a pK.sub.a value of from about 22 to about 36; and (ii) anions formed by reaction of such carbanions with the primary component of the mixture.

  2. Redox-Controlled Olefin (Co)Polymerization Catalyzed by Ferrocene-Bridged Phosphine-Sulfonate Palladium Complexes.

    PubMed

    Chen, Min; Yang, Bangpei; Chen, Changle

    2015-12-14

    The facile and reversible interconversion between neutral and oxidized forms of palladium complexes containing ferrocene-bridged phosphine sulfonate ligands was demonstrated. The activity of these palladium complexes could be controlled using redox reagents during ethylene homopolymerization, ethylene/methyl acrylate copolymerization, and norbornene oligomerization. Specifically in norbornene oligomerization, the neutral complexes were not active at all whereas the oxidized counterparts showed appreciable activity. In situ switching between the neutral and oxidized forms resulted in an interesting "off" and "on" behavior in norbornene oligomerization. This work provides a new strategy to control the olefin polymerization process. PMID:26768533

  3. Induced Circular Dichroism in Phosphine Gold(I) Aryl Acetylide Urea Complexes through Hydrogen-Bonded Chiral Co-Assemblies.

    PubMed

    Dubarle-Offner, Julien; Moussa, Jamal; Amouri, Hani; Jouvelet, Benjamin; Bouteiller, Laurent; Raynal, Matthieu

    2016-03-14

    Phosphine gold(I) aryl acetylide complexes equipped with a central bis(urea) moiety form 1D hydrogen-bonded polymeric assemblies in solution that do not display any optical activity. Chiral co-assemblies are formed by simple addition of an enantiopure (metal-free) complementary monomer. Although exhibiting an intrinsically achiral linear geometry, the gold(I) aryl acetylide fragment is located in the chiral environment displayed by the hydrogen-bonded co-assemblies, as demonstrated by induced circular dichroism (ICD). PMID:26780877

  4. Single-Component Phosphinous Acid Ruthenium(II) Catalysts for Versatile C-H Activation by Metal-Ligand Cooperation.

    PubMed

    Zell, Daniel; Warratz, Svenja; Gelman, Dmitri; Garden, Simon J; Ackermann, Lutz

    2016-01-01

    Well-defined ruthenium(II) phosphinous acid (PA) complexes enabled chemo-, site-, and diastereoselective C-H functionalization of arenes and alkenes with ample scope. The outstanding catalytic activity was reflected by catalyst loadings as low as 0.75?mol?%, and the most step-economical access reported to date to angiotensin?II receptor antagonist blockbuster drugs. Mechanistic studies indicated a kinetically relevant C-X cleavage by a single-electron transfer (SET)-type elementary process, and provided evidence for a PA-assisted C-H ruthenation step. PMID:26639161

  5. Phosphinate chemistry in the 21st century: a viable alternative to the use of phosphorus trichloride in organophosphorus synthesis.

    PubMed

    Montchamp, Jean-Luc

    2014-01-21

    Organophosphorus compounds are important in everyday applications ranging from agriculture to medicine and are used in flame retardants and other materials. Although organophosphorus chemistry is known as a mature and specialized area, researchers would like to develop new methods for synthesizing organophosphorus compounds to improve the safety and sustainability of these chemical processes. The vast majority of compounds that contain a phosphorus-carbon bond are manufactured using phosphorus trichloride (PCl3) as an intermediate. However, these reactions require chlorine, and researchers would like to avoid the use of PCl3 and develop safer chemistry that also decreases energy consumption and minimizes waste. Researchers have already proposed and discussed two primary strategies based on elemental phosphorus (P4 or Pred) or on phosphine (PH3) as alternatives to PCl3. However, phosphinates, an important class of phosphorus compounds defined as any compound with a phosphorus atom attached to two oxygens, R(1)R(2)P(O)(OR) (R(1)/R(2) = hydrogen/carbon), offer another option. This Account discusses the previously neglected potential of these phosphinates as replacements of PCl3 for the preparation of organophosphorus compounds. Because of their strong reductive properties, industry currently uses the simplest members of this class of compounds, hypophosphites, for one major application: electroless plating. In comparison with other proposed PCl3 surrogates, hypophosphorous derivatives can offer improved stability, lower toxicity, higher solubility, and increased atom economy. When their reducing power is harnessed to form phosphorus-carbon or phosphorus-oxygen bonds, these compounds are also rich and versatile precursors to organophosphorus compounds. This Account examines the use of transition metal-catalyzed reactions such as cross-coupling and hydrophosphinylation for phosphorus-carbon bond formation. Because the most important industrial organophosphorus compounds include compounds triply or quadruply bound to oxygen, I also discuss controlled transfer hydrogenation for phosphorus-oxygen bond formation. I hope that this Account will further promote research in this novel and exciting yet much underdeveloped area of phosphinate activation. PMID:23909275

  6. Phosphinic Amide as Directing Group Enabling Palladium(II)-Catalyzed ortho C-H Alkenylation of Anilines without and with Alkylation at the Nitrogen Atom.

    PubMed

    Jiao, Lin-Yu; Ferreira, Andr V; Oestreich, Martin

    2016-02-01

    A phosphinic amide is introduced as a directing group for the ortho C-H alkenylation of anilines. The new donor group distinguishes itself from existing ones by assisting the C-H bond activation of anilides without (NH group) and with alkylation (NMe group) at the amide nitrogen atom. The reactivity is even reversed with the methyl-substituted anilide being more reactive than its unsubstituted counterpart. Electron-donating substituents at the arene ring enhance their reactivity while halogenation is not tolerated. The phosphinic amide also enables the C-7-selective C-H alkenylation of indoline. PMID:26370493

  7. Synthesis and evaluation of some novel phosphate and phosphinate derivatives of araA. Studies on the mechanism of action of phosphate triesters.

    PubMed Central

    McGuigan, C; Shackleton, J M; Tollerfield, S M; Riley, P A

    1989-01-01

    A number of novel phosphinate and phosphate triester derivatives of the anti-viral nucleoside analogue araA have been prepared. Spectroscopic and analytical data have been collected on both the reagents and the nucleotides. An in vitro assay indicated inhibition of DNA synthesis by mammalian cells, by each of the nucleotide derivatives, in the range 3-30 microM. Inhibition was reduced, but not abolished, for the phosphinates relative to the phosphates. These results are consistent with a mode of action involving release of the free nucleoside araA and the nucleotide araAMP. PMID:2602149

  8. Diversity through phosphine catalysis identifies octahydro-1,6-naphthyridin-4-ones as activators of endothelium-driven immunity.

    PubMed

    Cruz, Daniel; Wang, Zhiming; Kibbie, Jon; Modlin, Robert; Kwon, Ohyun

    2011-04-26

    The endothelium plays a critical role in promoting inflammation in cardiovascular disease and other chronic inflammatory conditions, and many small-molecule screens have sought to identify agents that prevent endothelial cell activation. Conversely, an augmented immune response can be protective against microbial pathogens and in cancer immunotherapy. Yet, small-molecule screens to identify agents that induce endothelial cell activation have not been reported. In this regard, a bioassay was developed that identifies activated endothelium by its capacity to trigger macrophage inflammatory protein 1 beta from primary monocytes. Subsequently, a 642-compound library of 39 distinctive scaffolds generated by a diversity-oriented synthesis based on the nucleophilic phosphine catalysis was screened for small molecules that activated the endothelium. Among the active compounds identified, the major classes were synthesized through the sequence of phosphine-catalyzed annulation, Tebbe reaction, Diels-Alder reaction, and in some cases, hydrolysis. Ninety-six analogs of one particular class of compounds, octahydro-1,6-naphthyridin-4-ones, were efficiently prepared by a solid-phase split-and-pool technique and by solution phase analog synthesis. Structure-function analysis combined with transcriptional profiling of active and inactive octahydro-1,6-naphthyridin-4-one analogs identified inflammatory gene networks induced exclusively by the active compound. The identification of a family of chemical probes that augment innate immunity through endothelial cell activation provides a framework for understanding gene networks involved in endothelial inflammation as well as the development of novel endothelium-driven immunotherapeutic agents. PMID:21383121

  9. Developing five-membered heterocycle substituted phosphinous acids as ligands for palladium-catalyzed Suzuki-Miyaura and Catellani reactions.

    PubMed

    Chang, Ting-Wei; Ho, Pei-Yun; Mao, Kuo-Chung; Hong, Fung-E

    2015-10-21

    A new category of secondary phosphine oxides (SPOs) (5a-5j) with/without benzo-fused five-membered heterocyclic substituents were prepared. These new compounds are air- and moisture-stable ligands and have the advantage of long-term storage. Some of the ligands as well as ligand coordinated palladium complexes (6f' and 6f'') and platinum complexes (7b_trans & 7i_trans) were prepared and their structures were determined using single crystal X-ray diffraction methods. The crystal structure of 6f' revealed the formation of diamond shape di-palladium complexes with a Pd2Cl2 core. As for the structures of 7b_trans & 7i_trans, the processes for the generation of the trans-form of the bis-phosphine ligand coordinated platinum complexes are shown. These SPOs exhibit notable efficiencies in palladium-catalyzed Suzuki-Miyaura reactions. Moreover, organic compounds (9k and 10c) with unexpected conformations were obtained from Heck-type Catellani reactions. Reaction pathways are proposed to accommodate the probable routes for the formation of all organic products. PMID:26370178

  10. Synthesis of Monomeric Fe(II) and Ru(II) Complexes of Tetradentate Phosphines

    SciTech Connect

    Jana, Barun; Ellern, Arkady; Pestovsky, Oleg; Sadow, Aaron; Bakac, Andreja

    2011-03-07

    rac-Bis[{l_brace}(diphenylphosphino)ethyl{r_brace}-phenylphosphino]methane (DPPEPM) reacts with iron(II) and ruthenium(II) halides to generate complexes with folded DPPEPM coordination. The paramagnetic, five-coordinate Fe(DPPEPM)Cl{sub 2} (1) in CD{sub 2}Cl{sub 2} features a tridentate binding mode as established by {sup 31}P{l_brace}{sup 1}H{r_brace} NMR spectroscopy. Crystal structure analysis of the analogous bromo complex, Fe(DPPEPM)Br{sub 2} (2) revealed a pseudo-octahedral, cis-{alpha} geometry at iron with DPPEPM coordinated in a tetradentate fashion. However, in CD{sub 2}Cl{sub 2} solution, the coordination of DPPEPM in 2 is similar to that of 1 in that one of the external phosphorus atoms is dissociated resulting in a mixture of three tridentate complexes. The chloro ruthenium complex cis-Ru({kappa}{sup 4}-DPPEPM)Cl{sub 2} (3) is obtained from rac-DPPEPM and either [RuCl{sub 2}(COD)]{sub 2} [COD = 1,5-cyclooctadiene] or RuCl{sub 2}(PPh{sub 3}){sub 4}. The structure of 3 in both the solid state and in CD{sub 2}Cl{sub 2} solution features a folded {kappa}{sup 4}-DPPEPM. This binding mode was also observed in cis-[Fe({kappa}{sup 4}-DPPEPM)(CH{sub 3}CN){sub 2}](CF{sub 3}SO{sub 3}){sub 2} (4). Addition of an excess of CO to a methanolic solution of 1 results in the replacement of one of the chloride ions by CO to yield cis-[Fe({kappa}{sup 4}-DPPEPM)Cl(CO)](Cl) (5). The same reaction in CH{sub 2}Cl{sub 2} produces a mixture of 5 and [Fe({kappa}{sup 3}-DPPEPM)Cl{sub 2}(CO)] (6) in which one of the internal phosphines has been substituted by CO. Complexes 2, 3, 4, and 5 appear to be the first structurally characterized monometallic complexes of {kappa}{sup 4}-DPPEPM.

  11. Phosphine-Catalyzed Annulations of Azomethine Imines: Allene-Dependent [3 + 2], [3 + 3], [4 + 3], and [3 + 2 + 3] Pathways

    PubMed Central

    Na, Risong; Jing, Chengfeng; Xu, Qihai; Jiang, Hui; Wu, Xi; Shi, Jiayan; Zhong, Jiangchun; Wang, Min; Benitez, Diego; Tkatchouk, Ekaterina; Goddard, William A.; Guo, Hongchao; Kwon, Ohyun

    2011-01-01

    In this paper we describe the phosphine-catalyzed [3 + 2], [3 + 3], [4 + 3], and [3 + 2 + 3] annulations of azomethine imines and allenoates. These processes mark the first use of azomethine imines in nucleophilic phosphine catalysis, producing dinitrogen-fused heterocycles, including tetrahydropyrazolo-pyrazolones, -pyridazinones, -diazepinones, and -diazocinones. Counting the two different reaction modes in the [3 + 3] cyclizations, there are five distinct reaction pathways—the choice of which depends on the structure and chemical properties of the allenoate. All reactions are operationally simple and proceed smoothly under mild reaction conditions, affording a broad range of 1,2-dinitrogen–containing heterocycles in moderate to excellent yields. A zwitterionic intermediate formed from a phosphine and two molecules of ethyl 2,3-butadienoate acted as a 1,5-dipole in the annulations of azomethine imines, leading to the [3 + 2 + 3] tetrahydropyrazolodiazocinone products. The incorporation of two molecules of an allenoate into an eight-membered-ring product represents a new application of this versatile class of molecules in nucleophilic phosphine catalysis. The salient features of this protocol—the facile access to a diverse range of nitrogen-containing heterocycles and the simple preparation of azomethine imine substrates—suggest that it might find extensive applications in heterocycle synthesis. PMID:21812448

  12. Enantioselective [3 + 2] annulation of α-substituted allenoates with β,γ-unsaturated N-sulfonylimines catalyzed by a bifunctional dipeptide phosphine

    PubMed Central

    Ni, Huanzhen; Yao, Weijun

    2016-01-01

    Summary The first enantioselective [3 + 2] annulation of α-substituted allenoates with β,γ-unsaturated N-sulfonylimines is described. In the presence of a dipeptide phosphine catalyst, a wide range of highly functionalized cyclopentenes bearing an all-carbon quaternary center were obtained in moderate to good yields and with good to excellent enantioselectivities. PMID:26977194

  13. Rhodium- and Iridium-Catalyzed Asymmetric Addition of Optically Pure P-Chiral H-Phosphinates to Aldehydes Leading to Optically Active α-Hydroxyphosphinates.

    PubMed

    Li, Qiang; Chen, Tieqiao; Xu, Qing; Han, Li-Biao

    2016-04-25

    Optically active α-hydroxyphosphinates with both C- and P-stereogenic centers are obtained by rhodium- or iridium-catalyzed substrate-directed stereoselective addition of the optically pure H-phosphinates to aldehydes. The reaction most probably proceeds by a transition-metal-catalyzed mechanism with hydridometal complexes as key intermediates in the catalytic cycle. PMID:26934717

  14. Reversible Dimerization of Phosphine-Stabilized Silylenes by Silylene Insertion into Si(II) -H and Si(II) -Cl σ-Bonds at Room Temperature.

    PubMed

    Rodriguez, Ricardo; Contie, Yohan; Mao, Yanli; Saffon-Merceron, Nathalie; Baceiredo, Antoine; Branchadell, Vicenç; Kato, Tsuyoshi

    2015-12-01

    Contrary to the classical silylene dimerization leading to a disilene structure, phosphine stabilized hydro- and chloro-silylenes (2 a,b) undergo an unique dimerization via silylene insertion into SiX σ-bonds (X=H, Cl), which is reversible at room temperature. DFT calculations indicate that the insertion reaction proceeds in one step in a concerted manner. PMID:26482125

  15. Experimental and computational exploration of the dynamic behavior of (PNP)BF2, a boron compound supported by an amido/bis(phosphine) pincer ligand.

    PubMed

    DeMott, Jessica C; Surawatanawong, Panida; Barnett, Shoshanna M; Chen, Chun-Hsing; Foxman, Bruce M; Ozerov, Oleg V

    2011-11-21

    The diarylamido/bis(phosphine) PNP pincer ligand (2-(i)Pr(2)P-4-MeC(6)H(3))(2)N has been evaluated as a scaffold for supporting a BF(2) fragment. Compound (PNP)BF(2) (6) was prepared by simple metathesis of (PNP)Li (5) with Me(2)SBF(3). NMR spectra of 6 in solution are of apparent C(2) symmetry, suggestive of a symmetric environment about boron. However, a combination of X-ray structural studies, low-temperature NMR investigations, and DFT calculations consistently establish that the ground state of this molecule contains a classical four-coordinate boron with a PNBF(2) coordination environment, with one phosphine donor in PNP remaining "free". Fortuitous formation of a single crystal of (PNP)BF(2)·HBF(4) (7), in which the "free" phosphine is protonated, furnished another structure containing the same PNBF(2) environment about boron for comparison and the two PNBF(2) environments in 6 and 7 are virtually identical. DFT studies on several other diarylamido/bis(phosphine) pincer (PNP)BF(2) systems were carried out and all displayed a similar four coordinate PNBF(2) environment in the ground state structures. The symmetric appearance of the room-temperature NMR spectra is explained by the rapid interconversion between two degenerate four-coordinate, C(1)-symmetric ground-state forms. Lineshape analysis of the (1)H and (19)F NMR spectra over a temperature range of 180-243 K yielded the activation parameters ΔH(‡) = 8.1(3) kcal mol(-1) and ΔS(‡) = -6.0(15) eu, which are broadly consistent with the calculated values. Calculations indicate that the exchange of phosphine donors at the boron center proceeds by an intrinsically dissociative mechanism. PMID:21956286

  16. Summary of GPC/DV results for space exposed poly(arylene ether phosphine oxides). Final report

    SciTech Connect

    Siochi, E.

    1995-09-01

    Gel Permeation Chromatography (GPC) was used to analyze poly(arylene ether phosphine oxide)s whose backbones were identical except for the ketone content and placement. These samples were exposed to low Earth orbit environment (predominantly atomic oxygen) on space shuttle flights. The materials and their unexposed controls were then characterized by GPC to investigate the effect of atomic oxygen on the molecular weight distributions. Analysis of the soluble portion of the samples revealed that there was significant loss of high molecular weight species. The presence of insoluble material also suggested that crosslinking was induced by the atomic oxygen exposure and that this very likely occurred at the high molecular weight portion of the molecular weight distribution.

  17. Catalytic reduction of hydrazine to ammonia by a mononuclear iron(II) complex on a tris(thiolato)phosphine platform.

    PubMed

    Chang, Ya-Ho; Chan, Pooi-Mun; Tsai, Yi-Fang; Lee, Gene-Hsiang; Hsu, Hua-Fen

    2014-01-21

    To provide the mechanistic information of nitrogenase at a molecular level, much effort has been made to develop synthetic metal complexes that have enzyme-like reactivity. Herein we obtain an iron(II) complex binding with a tris(thiolato)phosphine ligand, [P(Ph)4][Fe(PS3″)(CH3CN)] [1; PS3″ = P(C6H3-3-Me3Si-2-S)3(3-)] that catalyzes the reduction of hydrazine, an intermediate and a substrate of nitrogenase. The substrate- and product-bound adducts, [N(Bu)4][Fe(PS3″)(N2H4)] (2) and [N(Et)4][Fe(PS3″)(NH3)] (3), respectively, are also synthesized. This work provides the feasibility that the late stage of biological nitrogen fixation can be conducted at a single iron site with a sulfur-rich ligation environment. PMID:24377381

  18. A General, Simple Catalyst for Enantiospecific Cross Couplings of Benzylic Ammonium Triflates and Boronic Acids: No Phosphine Ligand Required

    PubMed Central

    Basch, Corey H.; Song, Ye-Geun; Watson, Mary P.

    2014-01-01

    Highly improved conditions for the enantiospecific cross coupling of benzylic ammonium triflates with boronic acids are reported. This method relies on the use of Ni(cod)2 without ancillary phosphine or N-heterocyclic carbene ligands as catalyst. These conditions enable the coupling of new classes of boronic acids and benzylic ammonium triflates. In particular, both heteroaromatic and vinyl boronic acids are well tolerated as coupling partners. In addition, these conditions enable the use of ammonium triflates with a variety of substituents at the benzylic stereocenter. Further, naphthyl-substitution is not required on the benzylic ammonium triflate; ammonium triflates with simple aromatic substituents also undergo this coupling. Good to high yields and levels of stereochemical fidelity are observed. This new catalyst system greatly expands the utility of enantiospecific cross couplings of these amine-derived substrates for the preparation of highly enantioenriched products. PMID:25364060

  19. The preparation of sol-gel materials doped with ionic liquids and trialkyl phosphine oxides for yttrium(III) uptake.

    PubMed

    Liu, Yinghui; Sun, Xiaoqi; Luo, Fang; Chen, Ji

    2007-12-01

    A new material (IL923SGs) composed of ionic liquids and trialkyl phosphine oxides (Cyanex 923) for Y(III) uptake was prepared via a sol-gel method. The hydrophobic ionic liquid 1-octyl-3-methylimidazolium hexafluorophosphate (C8mim+ PF6(-)) was used as solvent medium and pore templating material. The extraction of Y(III) by IL923SGs was mainly due to the complexation of metal ions with Cyanex 923 doped in the solid silica. Ionic liquid was stably doped into the silica gel matrix providing a diffusion medium for Cyanex 923, and this will result in higher removal efficiencies and excellent stability for metal ions separation. IL923SGs were also easily regenerated and reused in the subsequent removal of Y(III) in four cycles. PMID:17996530

  20. Summary of GPC/DV results for space exposed poly(arylene ether phosphine oxide)s

    NASA Technical Reports Server (NTRS)

    Siochi, Emilie

    1995-01-01

    Gel Permeation Chromatography (GPC) was used to analyze poly(arylene ether phosphine oxide)s whose backbones were identical except for the ketone content and placement. These samples were exposed to low Earth orbit environment (predominantly atomic oxygen) on space shuttle flights. The materials and their unexposed controls were then characterized by GPC to investigate the effect of atomic oxygen on the molecular weight distributions. Analysis of the soluble portion of the samples revealed that there was significant loss of high molecular weight species. The presence of insoluble material also suggested that crosslinking was induced by the atomic oxygen exposure and that this very likely occurred at the high molecular weight portion of the molecular weight distribution.

  1. Solid-State (63)Cu, (65)Cu, and (31)P NMR Spectroscopy of Photoluminescent Copper(I) Triazole Phosphine Complexes.

    PubMed

    Yu, Huaguang; Tan, Xiuzhen; Bernard, Guy M; Terskikh, Victor V; Chen, Jinglin; Wasylishen, Roderick E

    2015-07-30

    The results of a solid-state (63/65)Cu and (31)P NMR investigation of several copper(I) complexes with functionalized 3-(2'-pyridyl)-1,2,4-triazole and phosphine ligands that have shown potential in the preparation of photoluminescent devices are reported. For each complex studied, distinct NMR parameters, with moderate (63)Cu nuclear quadrupolar coupling constant (CQ) values ranging from -17.2 to -23.7 MHz, are attributed to subtle variations in the distorted four-coordinate environments about the copper nuclei. The spans of the copper chemical shift (CS) tensors, δ11-δ33, for the mono- and bisphosphine complexes are also similar, ranging from 1000 to 1150 ppm, but that for a complex with a strained bidentate phosphine ligand is only 650 ppm. The effects of residual dipolar and indirect spin-spin coupling arising from the (63/65)Cu- (31)P spin pairs, observed in the solid-state (31)P NMR spectra of these complexes, yield information about the orientations of the copper electric field gradient (EFG) tensors relative to the Cu-P bond. Variable-temperature (31)P NMR measurements for [Cu(bptzH)(dppe)]ClO4 (bptzH = 5-tert-butyl-3-(2'-pyridyl)-1,2,4-triazole; dppe = 1,2-bis(diphenylphosphino)ethane), undertaken to investigate the cause of the broad unresolved spectra observed at room temperature, demonstrate that the broadening arises from partial self-decoupling of the (63/65)Cu nuclei, a consequence of rapid quadrupolar relaxation. Ab initio calculations of copper EFG and CS tensors were performed to probe relationships between NMR parameters and molecular structure. The analysis demonstrated that CQ((63/65)Cu) is negative for all complexes studied here and that the largest components of the EFG tensors are generally coincident with δ11. PMID:26101890

  2. Characterization of trans-dioxotechnetium(V) and technetium(II)phosphine excited states and spectroelectrochemical detection of pertechnetate

    SciTech Connect

    Bryan, Samuel A.; Del Negro, Andy S.; Wang, Zheming; Hubler, Timothy L.; Heineman, William R.; Seliskar, Carl J.; Sullivan, Brian P.

    2006-06-01

    We report the first examples of excited-state luminescence from technetium complexes. We have examined a series of trans-dioxo complexes of Tc(V) and a Tc(I/II) phosphine complex and compare their respective photophysical properties with the corresponding rhenium analogues. When excited with a 415 nm laser, the Tc(V) complexes luminesce in the 700-800 nm range and have excited state lifetimes in the range of several microseconds at room temperature. The low-temperature luminescence spectra of the technetium complexes have also been investigated. Distinct vibrational band progressions are resolved in the low-temperature luminescence spectra. Excited state lifetimes at 5 K vary between tens of microseconds to several milliseconds for the dioxo-technetium complexes. In addition, a previously known Tc(I) complex, [Tc(DMPE) 3]+ which has been used as a radiography imaging agent has been demonstrated in our labs to fluoresce in the visible wavelength region upon a one-electron reversible oxidation to form the Tc(II), [Tc(DMPE)3]2+ complex in aqueous solution. The luminescence of [Tc(DMPE)3]2+ was observed by illuminating the solution complex with a 404 nm excitation while performing the reversible electrochemical experiment. In a recent application, we have focused on making thin chemically-selective films for sensing radioactive technetium compounds and in this effort have developed a fluorescence-based spectroelectrochemical sensor. Characterization of the new dioxo-technetium(V) and technetium(II)phosphine excited states as well as application of the respective chromophores for use in a spectroelectrochemical sensor for pertechnetate will be discussed.

  3. The induction of cell death by phosphine silver(I) thiocyanate complexes in SNO-esophageal cancer cells.

    PubMed

    Human, Zelinda; Munyaneza, Appollinaire; Omondi, Bernard; Sanabria, Natasha M; Meijboom, Reinout; Cronj, Marianne J

    2015-02-01

    Esophageal cancer is one of the least studied cancers and is found to be prominent in black South African males. It is mainly diagnosed in the late stages, and patients tend to have a low 5-year survival rate of only 10%. Silver is generally used as an antimicrobial agent, with limited reports on anticancer studies. In this study, dimeric silver(I) thiocyanate complexes were used containing a variation of 4-substitued triphenylphosphines, including [AgSCN(PPh(3))(2)](2) (1), [AgSCN{P(4-MeC(6)H(4))(3)}(2)](2) (2), [AgSCN{P(4-FC(6)H(4))(3)}(2)](2) (3) and [AgSCN{P(4-ClC(6)H(4))(3)}(2)](2) (4). All four complexes, with their respective phosphine ligands, PPh(3) (L1), P(4-MeC(6)H(4))(3) (L2), P(4-FC(6)H(4))(3) (L3) and P(4-ClC(6)H(4))(3) (L4), were subjected to in vitro toxicity studies in SNO-esophageal cancer cells, using an alamarBlue() assay. Morphological changes, including blebbing and apoptotic body formation, were observed. Phosphatidylserine externalization, a marker of apoptosis, was quantified by flow cytometry. The phosphine ligands L1-L4, on their own, had minimal effect on the malignant while complexes 1-4 resulted in significant cell death. A 10x decreased concentration of these complexes had similar effects than cisplatin, used as the positive control. These complexes show promise as anticancer agents. PMID:25547071

  4. Phosphine, isocyanide, and alkyne reactivity at pentanuclear molybdenum/tungsten-iridium clusters.

    PubMed

    Simpson, Peter V; Randles, Michael D; Gupta, Vivek; Fu, Junhong; Moxey, Graeme J; Schwich, Torsten; Morshedi, Mahbod; Cifuentes, Marie P; Humphrey, Mark G

    2015-04-28

    The trigonal bipyramidal clusters M2Ir3(μ-CO)3(CO)6(η(5)-C5H5)2(η(5)-C5Me4R) (M = Mo, R = Me 1a, R = H; M = W, R = Me, H) reacted with isocyanides to give ligand substitution products M2Ir3(μ-CO)3(CO)5(CNR′)(η(5)-C5H5)2(η(5)-C5Me4R) (M = Mo, R = Me, R′ = C6H3Me2-2,6 3a; M = Mo, R = Me, R′ = (t)Bu 3b), in which core geometry and metal atom locations are maintained, whereas reactions with PPh3 afforded M2Ir3(μ-CO)4(CO)4(PPh3)(η(5)-C5H5)2(η(5)-C5Me4R) (M = Mo, R = Me 4a, H 4c; M = W, R = Me 4b, H), with retention of core geometry but with effective site-exchange of the precursors’ apical Mo/W with an equatorial Ir. Similar treatment of trigonal bipyramidal MIr4(μ-CO)3(CO)7(η(5)-C5H5)(η(5)-C5Me5) (M = Mo 2a, W 2b) with PPh3 afforded the mono-substitution products MIr4(μ-CO)3(CO)6(PPh3)(η(5)-C5H5)(η(5)-C5Me5) (M = Mo 5a; M = W 5b), and further reaction of the molybdenum example 5a with excess PPh3 afforded the bis-substituted cluster MoIr4(μ3-CO)2(μ-CO)2(CO)4(PPh3)2(η(5)-C5H5)(η(5)-C5Me5) (6). Reaction of 1a with diphenylacetylene proceeded with alkyne coordination and C≡C cleavage, affording Mo2Ir3(μ4–η(2)-PhC2Ph)(μ3-CPh)2(CO)4(η(5)-C5H5)2(η(5)-C5Me5) (7a) together with an isomer. Reactions of 2a and 2b with PhC≡CR afforded MIr4(μ3–η(2)-PhC2R)(μ3-CO)2(CO)6(η(5)-C5H5)(η(5)-C5Me5) (M = Mo, R = Ph 8a; M = W, R = Ph 8b, H; M = W, R = C6H4(C2Ph)-3 9a, C6H4(C2Ph)-4), while addition of 0.5 equivalents of the diynes 1,3-C6H4(C2Ph)2 and 1,4-C6H4(C2Ph)2 to WIr4(μ-CO)3(CO)7(η(5)-C5H5)(η(5)-C5Me5) gave the linked clusters [WIr4(CO)8(η(5)-C5H5)(η(5)-C5Me5)]2(μ6–η(4)-PhC2C6H4(C2Ph)-X) (X = 3, 4). The structures of 3a, 4a–4c, 5b, 6, 7a, 8a, 8b and 9a were determined by single-crystal X-ray diffraction studies, establishing the core isomerization of 4, the site selectivity for ligand substitution in 3–6, the alkyne C≡C dismutation in 7, and the site of alkyne coordination in 7–9. For clusters 3–6, ease of oxidation increases on increasing donor strength of ligand, increasing extent of ligand substitution, replacing Mo by W, and decreasing core Ir content, the Ir-rich clusters 5 and 6 being the most reversible. For clusters 7–9, ease of oxidation diminishes on replacing Mo by W, increasing the Ir content, and proceeding from mono-yne to diyne, although the latter two changes are small. In situ UV-vis-near-IR spectroelectrochemical studies of the (electrochemically reversible) reduction process of 8b were undertaken, the spectra becoming increasingly broad and featureless following reduction. The incorporation of isocyanides, phosphines, or alkyne residues in these pentanuclear clusters all result in an increased ease of oxidation and decreased ease of reduction, and thereby tune the electron richness of the clusters. PMID:25791388

  5. Theoretical insights into the effect of amine and phosphine decoration on the photoluminescence of copper(i) and silver(i) coordination polymers.

    PubMed

    Bayse, Craig A; Harper, Lenora K; Ming, Jasprina L; Pike, Robert D

    2014-08-01

    Coinage metal cyanides (MCN) form photoluminescent 1D coordination polymers. The decoration of these chains with amine and phosphine ligands shifts the wavelength for photoluminescence into the visible region. Density-functional theory (DFT) and time-dependent DFT (TD-DFT) calculations of zigzag and helical models of decorated chains are used to show that the transitions that contribute to the experimental spectra are related to the π-π excitations previously shown for coinage metal cyanide chains. PMID:24840102

  6. Phosphine-catalyzed [4+1] annulation of 1,3-(aza)dienes with maleimides: highly efficient construction of azaspiro[4.4]nonenes.

    PubMed

    Yang, Mei; Wang, Tianyi; Cao, Shixuan; He, Zhengjie

    2014-11-14

    Phosphine-catalyzed [4+1] annulation of electron-deficient 1,3-dienes or 1,3-azadienes with maleimides has been successfully developed under very mild conditions, providing a convenient and highly efficient method for constructing 2-azaspiro[4.4]nonenes and 1,7-diazaspiro[4.4]nonenes. This reaction represents the first example of [4+1] cyclization between electron-deficient 4π-conjugated systems and non-allylic phosphorus ylides. PMID:25233907

  7. Enantioselective Synthesis of Spirobarbiturate-Cyclohexenes through Phosphine-Catalyzed Asymmetric [4 + 2] Annulation of Barbiturate-Derived Alkenes with Allenoates.

    PubMed

    Liu, Honglei; Liu, Yang; Yuan, Chunhao; Wang, Guo-Peng; Zhu, Shou-Fei; Wu, Yang; Wang, Bo; Sun, Zhanhu; Xiao, Yumei; Zhou, Qi-Lin; Guo, Hongchao

    2016-03-18

    An enantioselective synthesis of pharmaceutically important spirobarbiturates has been achieved via spirocyclic chiral phosphine-catalyzed asymmetric [4 + 2] annulation of barbiturate-derived alkenes with allenoates. With the use of this tool, various spirobarbiturate-cyclohexenes are obtained in good to excellent yields with excellent diastereo- and enantioselectivities. A wide range of α-substituted allenoates and barbiturate-derived alkenes were tolerated. PMID:26937706

  8. Chemistry and stereochemistry of the interaction of the water-soluble phosphine [HO(CH2)3]3P with cinnamaldehyde in aqueous media.

    PubMed

    Moiseev, Dmitry V; James, Brian R; Hu, Thomas Q

    2007-05-28

    To learn more about the bleaching action of pulps by (hydroxymethyl)phosphines, cinnamaldehyde was reacted with tris(3-hydroxypropyl)phosphine, [HO(CH2)3]3P (THPP), in aqueous solution at room temperature under argon. Self-condensation of the aldehyde into two isomeric products, 2-benzyl-5-phenyl-pent-2,4-dienal and 5-phenyl-2-(phenylmethylene)-4-pentenal, is observed; this implies initial nucleophilic attack of the phosphine at the beta-carbon of the alpha,beta-unsaturated aldehyde. Reaction in D2O gives the same products in which all but the phenyl and CHO protons are replaced by deuterons. NMR studies are consistent with carbanion formation and subsequent condensation of two phosphonium-containing aldehyde moieties to generate the products with concomitant elimination of phosphine oxide. In D2O in the presence of HCl, THPP reversibly attacks the aldehyde-C atom to form the (alpha-hydroxy)phosphonium derivative [PhCH=C(H)CH(OD)PR3]Cl (where R=(CH2)3OD), which slowly converts into the deuterated bisphosphonium salt [R3PCH(Ph)CD(H)CH(OD)PR3]Cl2 via the deuterated monophosphonium salt [R3PCH(Ph)CD(H)CHO]Cl. The phosphonium intermediates and phosphonium products in this chemistry, although having up to three chiral carbon centers, are formed with high stereoselectivity just in enantiomeric forms. In acetone-H2O (1:1 v/v), a cross-condensation of cinnamaldehyde with acetone to give 6-phenyl-3,5-hexadien-2-one is promoted by THPP via generation of OH-. PMID:17432851

  9. A diphenyl ether derived bidentate secondary phosphine oxide as a preligand for nickel-catalyzed C-S cross-coupling reactions.

    PubMed

    Wellala, Nadeesha P N; Guan, Hairong

    2015-11-28

    A new bidentate secondary phosphine oxide (SPO) was synthesized from diphenyl ether via ortho-lithiation, phosphorylation with PhP(Cl)NEt2, and hydrolysis in an acidic medium. Nickel(0) species ligated with this new SPO was established as a more effective catalyst than Ni(0)-Ph2P(O)H for the cross-coupling of aryl iodides with aryl thiols. PMID:26456099

  10. Photochemical C-H activation and ligand exchange reactions of CpRe(PPh{sub 3}){sub 2}H{sub 2}. Phosphine dissociation is not involved

    SciTech Connect

    Jones, W.D.; Rosini, G.P.; Maguire, J.A.

    1999-04-26

    The dihydride CpRe(PPh{sub 3}){sub 2}H{sub 2} (1) catalyzes H/D exchange between C{sub 6}D{sub 6} and other arenes or alkanes. Compound 1 also undergoes photochemical phosphine substitution with PMe{sub 3} to give CpRe(PPh{sub 3})(PMe{sub 3})H{sub 2} and then CpRe(PMe{sub 2}){sub 2}H{sub 2}. Mechanistic studies of these reactions are inconsistent with [CpRe(PPh{sub 3})H{sub 2}] as an intermediate. An alternative mechanism is presented proposing that the active species for H/D exchange is the 14-electron cyclic allyl intermediate [({eta}{sup 3}-C{sub 5}H{sub 7})Re(PPh{sub 3}){sub 2}] (E), in which both hydrides have migrated from the rhenium to the cyclopentadienyl ligand. This intermediate accounts for the fact that (1) deuterium does not exchange into the hydride ligands of complex 1 during the H/D exchange catalysis and (2) phosphine substitution occurs by an associative pathway. The precursor to intermediate E, [({eta}{sup 4}-C{sub 5}H{sub 6})Re(PPh{sub 3}){sub 2}H] (D), can undergo reversible orthometalation, allowing H/D exchange between the hydride ligands and the ortho phosphine positions. Evidence is presented to support this new mechanism as well as to rule out other feasible mechanisms.

  11. A facile phosphine-free method for synthesizing PbSe nanocrystals with strong optical limiting effects.

    PubMed

    Wang, Tian-Ming; Gao, Bao; Wang, Qiang; Zhao, Min; Kang, Kai-Bin; Xu, Zhu-Guo; Zhang, Hao-Li

    2013-05-01

    PbSe semiconductor nanocrystals (NCs) have attracted ever-growing interest owing to both their fundamental physics and potential applications in a diverse range of fields such as optoelectronic devices and nonlinear optics. The current fabrication strategy for colloidal PbSe NCs, however, frequently involves acutely toxic reagents and tedious reaction procedures, and is plagued by products with poorly controlled size and morphology. Herein, we report a facile, low-cost, and phosphine-free method for synthesizing PbSe NCs, which provides highly uniform NCs with tunable mid-IR absorption, and they are promising for bio-related applications. These high quality NCs were obtained by the reaction of elemental Se and PbCl2 in oleylamine as both the ligand and reaction medium. The high flexibility and reproducibility of the method reported in this study allows us to synthesize monodispersed PbSe NCs with well-controlled size and morphology. In addition, these products show strong optical limiting effects, and thus hold potential for developing nonlinear optical devices. PMID:23447458

  12. Ruthenium(III)/phosphine/pyridine complexes applied in the hydrogenation reactions of polar and apolar double bonds

    NASA Astrophysics Data System (ADS)

    Rodrigues, Claudia; Delolo, Fábio G.; Ferreira, Lucas M.; da S. Maia, Pedro I.; Deflon, Victor M.; Rabeah, Jabor; Brückner, Angelika; Norinder, Jakob; Börner, Armin; Bogado, André L.; Batista, Alzir A.

    2016-05-01

    In this work, five ruthenium(III) complexes containing phosphine and pyridine based ligands with general formula mer-[RuCl3(dppb)(N)] [where dppb = 1,4-bis(diphenylphosphino)butane and N = pyridine (py), 4-methylpyridine (4-Mepy), 4-vinylpyridine (4-Vpy), 4-tert-butylpyridine (4-tBupy) and 4-phenylpyridine (4-Phpy)] were synthesized and characterized using spectroscopic and electrochemical techniques, as well as magnetic susceptibility to check the paramagnetism of these compounds. These complexes were tested as catalytic precursors in hydrogenation reactions with cyclohexene, undecanal and cyclohexanecarboxaldehyde, as compounds bearing Cdbnd C and Cdbnd O groups. Broad screening was carried out in order to find the optimal reaction conditions with the highest conversion. It was found that by using a ratio of Ru-catalyst/substrate = 1:530 at 80 °C and 15 bar of H2 for 24 h, cyclohexene can be reduced. Hydrogenation of undecanal was possible using a Ru-catalyst/substrate ratio of 1:100 at 160 °C and 100 bar for 24 h, and for the reduction of cyclohexanecarboxaldehyde the reaction conditions were Ru-catalyst/substrate ratio of 1:100 at 160 °C and 50 bar for 24 h.

  13. Syntheses, characterization and antifungal activity of heteroleptic nickel(II) complexes with N-alkylsulfonyldithiocarbimates and phosphines

    NASA Astrophysics Data System (ADS)

    Vidigal, Antonio E. C.; Rubinger, Mayura M. M.; Oliveira, Marcelo R. L.; Guilardi, Silvana; Souza, Rafael A. C.; Ellena, Javier; Zambolim, Laércio

    2016-06-01

    Four nickel(II) complexes of general formula [Ni(RSO2Ndbnd CS2) (PPh3)2] where R = CH3 (2a), CH3CH2 (2b), CH3(CH2)3 (2c) and CH3(CH2)7 (2d) and PPh3 = triphenylphosphine; and two nickel(II) complexes of general formula [Ni(RSO2Ndbnd CS2)dppe] where R = CH3(CH2)3 (3c) and CH3(CH2)7 (3d) and dppe = 1,2-bis(diphenylphosphine)ethane) were prepared. These new complexes were obtained by the reaction of nickel(II) chloride hexahydrate with potassium N-alkylsulfonyldithiocarbimates and the appropriate phosphine using ethanol/water as solvent. The IR, UV-Vis and 1H, 13C and 31P NMR spectra, elemental analysis of Ni and the HR-ESI-MS were consistent with the formation of square planar nickel(II) complexes with mixed ligands. The structures of the compounds 2b and 2c were determined by single crystal X-ray diffraction. The compounds are isostructural and crystallize in the space group P 1 bar of the triclinic system. The activities of the complexes were investigated in vitro against Botrytis cinerea, Colletotrichum acutatum and Alternaria solani, fungi species that affect various commercially important plants. All the complexes were active.

  14. Copper(i) complexes with phosphine derived from sparfloxacin. Part II: a first insight into the cytotoxic action mode.

    PubMed

    Komarnicka, U K; Starosta, R; Płotek, M; de Almeida, R F M; Jeżowska-Bojczuk, M; Kyzioł, A

    2016-03-15

    In this paper we present a first insight into the cytotoxic action mode of copper(i) iodide or copper(i) thiocyanate complexes with a phosphine derivative of sparfloxacin (a 3(rd) generation fluoroquinolone antibiotic agent) and 2,9-dimethyl-1,10-phenanthroline or 2,2'-biquinoline as auxiliary ligands. The in vitro cytotoxic activity of the new complexes was tested against two cancer cell lines (CT26 - mouse colon carcinoma and A549 - human lung adenocarcinoma). An ICP-MS study revealed a marked time-dependent intracellular copper accumulation of the tested compounds. In addition, confocal microscopy imaging showed accumulation of the complexes inside whole cells and their emission of blue light. The complexes generate reactive oxygen species in the cancer cells, which was examined by using two different fluorescent probes. Moreover, (i) DNA intercalation studied by luminescence spectroscopy, circular dichroism and molecular docking, and (ii) plasmid DNA damage also demonstrate their significant cytotoxicity. All these observed biological effects contribute to the induction of apoptosis, observed at a great predominance. PMID:26674970

  15. Exploiting the Brønsted Acidity of Phosphinecarboxamides for the Synthesis of New Phosphides and Phosphines

    PubMed Central

    Jupp, Andrew R; Trott, Gemma; Payen de la Garanderie, Éléonore; Holl, James D G; Carmichael, Duncan; Goicoechea, Jose M

    2015-01-01

    We demonstrate that the synthesis of new N-functionalized phosphinecarboxamides is possible by reaction of primary and secondary amines with PCO− in the presence of a proton source. These reactions proceed with varying degrees of success, and although primary amines generally afford the corresponding phosphinecarboxamides in good yields, secondary amines react more sluggishly and often give rise to significant decomposition of the 2-phosphaethynolate precursor. Of the new N-derivatized phosphinecarboxamides available, PH2C(O)NHCy (Cy=cyclohexyl) can be obtained in sufficiently high yields to allow for the exploration of its Brønsted acidity. Thus, deprotonating PH2C(O)NHCy with one equivalent of potassium bis(trimethylsilyl)amide (KHMDS) gave the new phosphide [PHC(O)NHCy]−. In contrast, deprotonation with half of an equivalent gives rise to [P{C(O)NHCy}2]− and PH3. These phosphides can be employed to give new phosphines by reactions with electrophiles, thus demonstrating their enormous potential as chemical building blocks. PMID:25892576

  16. Water-Soluble Phosphine-Protected Au11 Clusters: Synthesis, Electronic Structure, and Chiral Phase Transfer in a Synergistic Fashion.

    PubMed

    Yao, Hiroshi; Iwatsu, Mana

    2016-04-01

    Synthesis of atomically precise, water-soluble phosphine-protected gold clusters is still currently limited probably due to a stability issue. We here present the synthesis, magic-number isolation, and exploration of the electronic structures as well as the asymmetric conversion of triphenylphosphine monosulfonate (TPPS)-protected gold clusters. Electrospray ionization mass spectrometry and elemental analysis result in the primary formation of Au11(TPPS)9Cl undecagold cluster compound. Magnetic circular dichroism (MCD) spectroscopy clarifies that extremely weak transitions are present in the low-energy region unresolved in the UV-vis absorption, which can be due to the Faraday B-terms based on the magnetically allowed transitions in the cluster. Asymmetric conversion without changing the nuclearity is remarkable by the chiral phase transfer in a synergistic fashion, which yields a rather small anisotropy factor (g-factor) of at most (2.5-7.0) × 10(-5). Quantum chemical calculations for model undecagold cluster compounds are then used to evaluate the optical and chiroptical responses induced by the chiral phase transfer. On this basis, we find that the Au core distortion is ignorable, and the chiral ion-pairing causes a slight increase in the CD response of the Au11 cluster. PMID:26986535

  17. Probing the Ag, Au, and Cu electrode/pyridine-α-hydroxymethyl biphenyl phosphine oxide isomer interface with SERS

    NASA Astrophysics Data System (ADS)

    Pięta, Ewa; Proniewicz, Edyta; Boduszek, Bogdan; Olszewski, Tomasz K.; Nattich-Rak, Małgorzata; Kim, Younkyoo

    2015-04-01

    The potential-dependent surface enhanced Raman scattering (SERS) and generalized two-dimensional correlation analysis (G2DCA) methods were used to characterize three pyridine-α-hydroxymethyl biphenyl phosphine oxide isomers: (diphenylphosphoryl)(pyridine-2-yl)methanol (α-Py), (diphenylphosphoryl)(pyridine-3-yl)methanol (β-Py), and (diphenylphosphoryl)(pyridine-4-yl)methanol (γ-Py). The aforementioned compounds were deposited onto Ag, Au, and Cu electrode surfaces under different applied electrode potentials in an aqueous solution at physiological pH. On the basis of the enhancement, broadening, and shift in wavenumbers of individual bands, the geometry of the investigated molecules and influence of substituent position on the adsorption mode (in the α-(2-), β-(3-), and γ-(4-) positions), electrode type, and applied electrode potential were examined. It was found that the SERS spectra are dominated by bands assigned to phenyl (Ph) and pyridine (Py) ring vibrations. However, some differences in the arrangement of the aforementioned fragments were observed with changes to the type of the metal surface and the applied electrode potential.

  18. Fourier transform infrared study on microemulsion system of potassium salt of bis(2-ethylhexyl) phosphinic acid (HA)

    NASA Astrophysics Data System (ADS)

    Zhou, Weijin; Shi, Nai; Wang, Yi; Chang, Zhiyuan; Wu, JinGuang

    1994-01-01

    To study microemulsion formation in a solvent extraction system is to probe into some basic principles of extraction chemistry in the light of combining extraction chemistry with surface chemistry. In our previous investigations, the microemulsions of the salts of HDEHP and PC88A have been studied systematically by FT-IR. In the experiment, we observed the change of peak positions and intensities of P equals O, P-O-C and P-O-H groups during saponification and hydration, and discovered that the peak of P-O-C splits apart into 1045 and 1075 cm-1. The vibration frequency of the P-O-C group in HDEHP and PC88A is quite close to the symmetric stretching frequency of the POO- group, and thus causes difficulties in the study of their peak position and absorbance variation. For this reason we synthesized bis(2-ethylhexyl) phosphinic acid without the P-O-C group. Infrared spectra in the range of 800 - 4000 cm-1 of this microemulsion system was studied.

  19. Addition of Zn during the phosphine-based synthesis of indium phospide quantum dots: doping and surface passivation

    PubMed Central

    Vinokurov, Alexander A; Lebedev, Oleg I; Kuznetsova, Tatiana A; Dorofeev, Sergey G

    2015-01-01

    Summary Zinc-doped InP(Zn) colloidal quantum dots (QDs) with narrow size distribution and low defect concentration were grown for the first time via a novel phosphine synthetic route and over a wide range of Zn doping. We report the influence of Zn on the optical properties of the obtained quantum dots. We propose a mechanism for the introduction of Zn in the QDs and show that the incorporation of Zn atoms into the InP lattice leads to the formation of Zn acceptor levels and a luminescence tail in the red region of the spectra. Using photochemical etching with HF, we confirmed that the Zn dopant atoms are situated inside the InP nanoparticles. Moreover, doping with Zn is accompanied with the coverage of the QDs by a zinc shell. During the synthesis Zn myristate covers the QD nucleus and inhibits the particle growth. At the same time the zinc shell leads to an increase of the luminescence quantum yield through the reduction of phosphorous dangling bonds. A scenario for the growth of the colloidal InP(Zn) QDs was proposed and discussed. PMID:26114082

  20. Synergistic extraction of rare earths with bis(2,4,4-trimethyl pentyl) dithiophosphinic acid and trialkyl phosphine oxide.

    PubMed

    Reddy, M L; Bosco Bharathi, J R; Peter, S; Ramamohan, T R

    1999-08-23

    Synergistic extraction of trivalent rare earths from nitrate solutions using mixtures of bis(2,4,4-trimethylpentyl)dithiophosphinic acid (Cyanex 301=HX) and trialkyl phosphine oxide (Cyanex 923=TRPO) in xylene has been investigated. The results demonstrate that these trivalent metal ions are extracted into xylene as MX(3).3HX with Cyanex 301 alone. In the presence of Cyanex 923, La(III) and Nd(III) are found to be extracted as MX(2).NO(3).TRPO. On the other hand, Eu(III), Y(III) and heavier rare earths are found to be extracted as MX(3).HX.2TRPO. The addition of a trialkylphosphine oxide to the metal extraction system not only enhances the extraction efficiency of these metal ions but also improves the selectivities significantly, especially between yttrium and heavier lanthanides. The separation factors between these metal ions were calculated and compared with that of commercially important extraction systems like di-2-ethylhexyl phosphoric acid. PMID:18967697

  1. Cyclic voltammetric study of the redox system of glutathione using the disulfide bond reductant tris(2-carboxyethyl)phosphine.

    PubMed

    Kizek, René; Vacek, Jan; Trnková, Libuse; Jelen, Frantisek

    2004-06-01

    The stabilization of the reduction state of proteins and peptides is very important for the monitoring of protein-protein, protein-DNA and protein-xenobiotic interactions. The reductive state of protein or peptide is characterized by the reactive sulfhydryl group. Glutathione in the reduced (GSH) and oxidized (GSSG) forms was studied by cyclic voltammetry. Tris(2-carboxyethyl)phosphine (TCEP) as the disulfide bond reductant and/or hydrogen peroxide as the sulfhydryl group oxidant were used. Cyclic voltammetry measurements, following the redox state of glutathione, were performed on a hanging mercury drop electrode (HMDE) in borate buffer (pH 9.2). It was shown that in aqueous solutions TCEP was able to reduce disulfide groups smoothly and quantitatively. The TCEP response at -0.25 V vs. Ag/AgCl/3 M KCl did not disturb the signals of the thiol/disulfide redox couple. The origin of cathodic and anodic signals of GSH (at -0.44 and -0.37 V) and GSSG (at -0.69 and -0.40 V) glutathione forms is discussed. It was shown that the application of TCEP to the conservation of sulfhydryl groups in peptides and proteins can be useful instrument for the study of peptides and proteins redox behavior. PMID:15110242

  2. Identification of phosphinate dipeptide analog inhibitors directed against the Plasmodium falciparum M17 leucine aminopeptidase as lead antimalarial compounds.

    PubMed

    Skinner-Adams, Tina S; Lowther, Jonathan; Teuscher, Franka; Stack, Colin M; Grembecka, Jolanta; Mucha, Artur; Kafarski, Pawel; Trenholme, Katharine R; Dalton, John P; Gardiner, Donald L

    2007-11-29

    Previous studies have pinpointed the M17 leucyl aminopeptidase of Plasmodium falciparum (PfLAP) as a target for the development of new antimalarials. This metallo-exopeptidase functions in the terminal stages of hemoglobin digestion and is inhibited by bestatin, a natural analog of Phe-Leu. By screening novel phosphinate dipeptide analogues for inhibitory activity against recombinant PfLAP, we have discovered two compounds, 4 (hPheP[CH2]Phe) and 5 (hPheP[CH2]Tyr), with inhibitory constants better than bestatin. These compounds are fast, tight-binding inhibitors that make improved contacts within the active site of PfLAP. Both compounds inhibit the growth of P. falciparum in vitro, exhibiting IC50 values against the chloroquine-resistant clone Dd2 of 20-40 and 12-23 muM, respectively. While bestatin exhibited some in vivo activity against Plasmodium chabaudi chabaudi, compound 4 reduced parasite burden by 92%. These studies establish the PfLAP as a prime target for the development of antimalarial drugs and provide important new lead compounds. PMID:17960925

  3. Chlorido(chloro­diphenyl­phosphine-κP)(diphenyl­piperidinophosphine-κP)(η5-penta­methyl­cyclo­penta­dien­yl)ruthenium(II)

    PubMed Central

    Jantscher, Florian; Kirchner, Karl; Mereiter, Kurt

    2009-01-01

    The title compound, [Ru(C10H15)Cl(C12H10ClP)(C17H20NP)], is a half-sandwich complex of RuII with the chloro­diphenyl­phosphine ligand formed from the diphenyl­piperidinophosphine and chlorine of the precursor complex [Ru(η5-C5Me5)(κ1P—Ph2PNC5H10)Cl2] by an unexpected reaction with NaBH4. The complex has a three-legged piano-stool geometry, with Ru—P bond lengths of 2.2598 (5) Å for the chloro­phosphine and 2.3303 (5) Å for the amino­phosphine. PMID:21583392

  4. Cytotoxicity in human cancer cells and mitochondrial dysfunction induced by a series of new copper(I) complexes containing tris(2-cyanoethyl)phosphines.

    PubMed

    Zanella, Alessandro; Gandin, Valentina; Porchia, Marina; Refosco, Fiorenzo; Tisato, Francesco; Sorrentino, Francesca; Scutari, Guido; Rigobello, Maria Pia; Marzano, Cristina

    2011-12-01

    Over the last few years a lot of research has been done to develop novel metal-based anti-cancer drugs, with the aim of improving clinical effectiveness, reducing general toxicity, and broadening the spectrum of activity. The search for novel metal-based antitumour drugs other than Pt agents includes the investigation of the cytotoxic activity of copper(I/II) compounds. Among these copper agents, particular attention has been recently devoted to hydrophilic copper(I) species bearing phosphines because of their noteworthy stability in aqueous media together with their remarkable in vitro cytotoxic activity. In this study we report on the synthesis, characterization and cytotoxic assays of a series of Cu(I) complexes with tris(2-cyanoethyl)phosphine (PCN) and bis(2-cyanoethyl)phenylphosphine (PCNPh). They were prepared by reaction of [Cu(CH(3)CN)(4)](+) or CuX(2) precursors with the pertinent phosphine in acetone or acetonitrile solutions producing compounds of the following formulation: [Cu(PCN)(2)](+) 2, [Cu(CH(3)CN)(PCN)](+) 3, [Cu(X)(PCN)] (X = Cl, 4; Br, 5), and [Cu(PCNPh)(2)](+) 6. The new copper(I) complexes were tested for their cytotoxic properties against a panel of several human tumour cell lines. Cellular copper uptake rate was correlated with cell growth inhibition in 2008 human ovarian cancer cells. Moreover, copper(I)-PCN complexes were evaluated for their ability to alter the most relevant mitochondrial pathophysiological parameters such as respiration, coupling, ATP-synthetase activity and membrane potential in isolated mitochondria. These data were correlated with changes in mitochondrial membrane potential and production of reactive oxygen species (ROS) in drug-treated 2008 cells. PMID:20567997

  5. Higher coordinate gold(I) complexes with the weak Lewis base tri(4-fluorophenyl) phosphine. Synthesis, structural, luminescence, and DFT studies

    NASA Astrophysics Data System (ADS)

    Agbeworvi, George; Assefa, Zerihun; Sykora, Richard E.; Taylor, Jared; Crawford, Carlos

    2016-03-01

    The structures and spectroscopic properties of two high coordinate gold(I) phosphine complexes with the TFFPP=tri(4-fluorophenyl)phosphine ligand are reported. Synthesis in a 1:3 metal to ligand ratio provided the compound [AuCl(TFFPP)3] (2) that crystallize in the P 1 bar space group, where the asymmetric unit consists of three independent molecules. In all three sites, two sets of bond angles display distinctly different ranges. The three P-Au-P angles have average values of 117.92°, 117.57°, and 114.78° for sites A, B, and C, with the corresponding P-Au-Cl angles of 98.31°, 99.05°, and 103.38°, respectively. The chloride ion coordinates as the fourth ligand, at the corresponding Au-Cl distance of 2.7337, 2.6825, and 2.6951 Å for the three sites. This distance is longer by 0.40-0.45 Å than the Au-Cl distance found in the mono TFFPP complex 1 (2.285 Å) indicating a weakening of the Au-Cl interaction as the coordination number increases. In compound 3, [Au(TFFPP)3]Cl·½CH2Cl2·H2O, the structure consists of three phosphine ligands bound to the gold(I) atom, but the Cl- exists as uncoordinated counter anion. The structural differences observed in the two complexes are attributable to crystal-packing effects caused by the introduction of H-bonding as well as enhanced intra and inter-molecular π-interaction in 3. The photoluminescence of the complexes compared with that of the ligand show ligand centered emission perturbed by the metal coordination. Theoretical DFT studies conducted on these complexes supports assignments of the electronic transitions observed in these systems.

  6. Probing the Carbon-phosphorus Bond Coupling in Low-temperature Phosphine PH3—Methane CH4 Interstellar Ice Analogues

    NASA Astrophysics Data System (ADS)

    Turner, Andrew M.; Abplanalp, Matthew J.; Kaiser, Ralf I.

    2016-03-01

    Phosphine, which has now been confirmed around the carbon-rich star IRC+10216, provides the first example of a phosphorus-containing single bond in interstellar or circumstellar media. While four compounds containing both phosphorus and carbon have been discovered, none contain a carbon-phosphorus single bond. Here, we show that this moiety is plausible from the reaction of phosphine with methane in electron-irradiated interstellar ice analogues. Fractional sublimation allows for detection of individual products at distinct temperatures using reflectron time-of-flight mass spectrometry (ReTOF) coupled with vacuum ultraviolet photoionization. This method produced phosphanes and methylphosphanes as large as P8H10 and CH3P8H9, which demonstrates that a phosphorus-carbon bond can readily form and that methylphosphanes sublime at 12-17 K higher temperatures than the non-organic phosphanes. Also, irradiated ices of phosphine with deuterated-methane untangle the reaction pathways through which these methylphosphanes were formed and identified radical recombination to be preferred over carbene/phosphinidene insertion reactions. In addition, these ReTOF results confirm that CH3PH2 and CH6P2 can form via insertion of carbene and phosphinidene and that the methylenediphosphine (PH2CH2PH2) isomer forms in the ices, although methylphosphine (CH3P2H3) is likely the more abundant isomer and that phosphanes and organophosphanes preferentially fragment via the loss of a phosphino group when photoionized. While the formation of methylphosphine is overall endoergic, the intermediates produced by interactions with energetic electrons proceed toward methylphosphine favorably and barrierlessly and provide plausible mechanisms toward hitherto unidentified interstellar compounds.

  7. Bis(phosphinic)diamido yttrium amide, alkoxide, and aryloxide complexes: an evaluation of lactide ring-opening polymerization initiator efficiency.

    PubMed

    Platel, Rachel H; White, Andrew J P; Williams, Charlotte K

    2011-08-15

    The synthesis and characterization of a series of bis(phosphinic)diamido yttrium alkoxide, amide, and aryloxide initiators are reported. The new complexes are characterized using multinuclear nuclear magnetic resonance (NMR) spectroscopy, elemental analysis, and, in some cases, X-ray crystallography. The alkoxide complexes are all dimeric in both the solid state and in solution, as are the amide complexes substituted with iso-propyl or phenyl groups on the phosphorus atoms. On the other hand, increasing the steric hindrance of the phosphorus substituents (tert-butyl), enables isolation of mononuclear yttrium amide complexes with either 2,2-dimethylpropylene or ethylene diamido ligand backbones. The complex of 2,6-di-tert-butyl-4-methylphenoxide is also mononuclear. All the new complexes are efficient initiators for rac-lactide ring-opening polymerization. The polymerization kinetics are compared and pseudo first order rate constants, k(obs), determined. The polymerization control is also discussed, by monitoring the number-averaged molecular weight, M(n), and polydispersity index, PDI, obtained using gel permeation chromatography (GPC). The alkoxide complexes are the most efficient initiators, showing very high rates and good polymerization control, behavior consistent with rapid rates of initiation. The phenoxide and amide complexes are less efficient as manifest by nonlinear regions in the kinetic plots, lower values for k(obs), and reduced polymerization control. One of the mononuclear yttrium amide complexes shows heteroselectivity in the polymerization of rac-lactide; however, this effect is reduced on changing the initiating group to phenoxide or on changing the ancillary ligand diamido backbone group. PMID:21749161

  8. High-efficiency turquoise-blue electrophosphorescence from a Pt(II)-pyridyltriazolate complex in phosphine oxide host

    SciTech Connect

    Bhansali, Unnat S; Polikarpov, Evgueni; Swensen, James S; Chen, Wei; Jia, Huiping; Gaspar, Daniel J; Gnade, Bruce E; Padmaperuma, Asanga B; Omary, Mohammad A

    2009-12-10

    We have demonstrated high-efficiency turquoise-blue electrophosphorescence from the complex Pt(ptp)2 = bis[3,5–bis(2–pyridyl)–1,2,4–triazolato]platinum(II) doped in the wide band-gap, ambipolar phosphine oxide host HM-A1 = 4-(diphenylphosphoryl)-N,N-diphenylaniline. For devices with 5% Pt(ptp)2 doping in HM-A1, we have achieved a peak external quantum efficiency and power efficiency of (11.8 ± 0.6) % and (61.2 ± 5.9) lm/W with high-pixel values of 13.1 % and 70.6 lm/W, respectively. These parameters maintained (10.6 ± 0.2) % and (40.3 ± 1.2) lm/W at a brightness of 1000 cd/m2 with high-pixel values of 10.8 % and 41.6 lm/W. Examination of several device structures suggests that the high performance is due to improved charge transport and exciton confinement in the emissive region. Devices with 1-10% doping concentration exhibit turquoise-blue emissions (λmax ~ 480 nm) with a monotonic decrease in monomer/excimer intensity ratio upon increasing the doping concentration. Devices with 5% doping exhibit sufficient blue contribution to attain white light upon combination with highly-doped or neat emissive layers of the same phosphor; the work herein represents a significant backdrop toward optimizing such white OLEDs given the performance metrics above, which to our knowledge represent the highest performance for OLEDs that exhibit blue emission maxima.

  9. Observing Initial Steps in Gold-Catalyzed Alkyne Transformations by Utilizing Bodipy-Tagged Phosphine-Gold Complexes.

    PubMed

    Vasiuta, Roman; Plenio, Herbert

    2016-04-25

    The Pd-catalyzed reactions of 3-chloro-bodipy with R2 PH (R=Ph, Cy) provide nonfluorescent bodipy-phosphines 3-PR2 -bodipy 3 a (R=Ph) and 3 b (R=Cy; quantum yield Φ<0.001). Metal complexes such as [AgCl(3 b)] and [AuCl(3 b)] were prepared and shown to display much higher fluorescence (Φ=0.073 and 0.096). In the gold complexes, the level of fluorescence was found to be qualitatively correlated with the electron density at gold. Consequently, the fluorescence brightness of [AuCl(3 b)] increases when the chloro ligand is replaced by a weakly coordinating anion, whereas upon formation of the electron-rich complex [Au(SR)(3 b)] the fluorescence is almost quenched. Related reactions of [AuCl(3 b)] with [Ag]ONf)] (Nf= nonaflate) and phenyl acetylenes enable the tracking of initial steps in gold-catalyzed reactions by using fluorescence spectroscopy. Treatment of [AuCl(3 b)] with [Ag(ONf)] gave the respective [Au(ONf)(3 b)] only when employing more than 2.5 equivalents of silver salt. The reaction of the "cationic" gold complex with phenyl acetylenes leads to the formation of the respective dinuclear cationic [{(3 b)Au}2 (CCPh)](+) and an increase in the level of fluorescence. The rate of the reaction of [Au(ONf)(3 b)] with PhCCH depends on the amount of silver salt in the reaction mixture; a large excess of silver salt accelerates this transformation. In situ fluorescence spectroscopy thus provides valuable information on the association of gold complexes with acetylenes. PMID:27011061

  10. Chiral Platinum(II) Complexes Featuring Phosphine and Chloroquine Ligands as Cytotoxic and Monofunctional DNA-Binding Agents.

    PubMed

    Villarreal, Wilmer; Colina-Vegas, Legna; Rodrigues de Oliveira, Clayton; Tenorio, Juan C; Ellena, Javier; Gozzo, Fábio C; Cominetti, Marcia Regina; Ferreira, Antonio G; Ferreira, Marco Antonio Barbosa; Navarro, Maribel; Batista, Alzir A

    2015-12-21

    Chiral molecules in nature are involved in many biological events; their selectivity and specificity make them of great interest for understanding the behavior of bioactive molecules, by providing information about the chiral discrimination. Inspired by these conformational properties, we present the design and synthesis of novel chiral platinum(II) complexes featuring phosphine and chloroquine ligands with the general formula [PtCl(P)2(CQ)]PF6 (where (P)2 = triphenylphosphine (PPh3) (5), 1,3-bis(diphenylphosphine)propane (dppp) (6), 1,4-bis(diphenylphosphine)butane (dppb) (7), 1,1'-bis(diphenylphosphine)ferrocene (dppf) (8), and CQ = chloroquine] and their precursors of the type [PtCl2(P)2] are described. The complexes were characterized by elemental analysis, absorption spectroscopy in the infrared and ultraviolet-visible (UV-vis) regions, multinuclear ((1)H, (13)C, (31)P, (15)N, and (195)Pt) NMR spectroscopy, cyclic voltammetry, and mass spectrometry (in the case of chloroquine complexes). The interactions of the new platinum-chloroquine complexes with both albumin (BSA), using fluorescence spectroscopy, and DNA, by four widely reported methods were also evaluated. These experiments showed that these Pt-CQ complexes interact strongly with DNA and have high affinities for BSA, in contrast to CQ and CQDP (chloroquine diphosphate), which interact weakly with these biomolecules. Additional assays were performed in order to investigate the cytotoxicity of the platinum complexes against two healthy cell lines (mouse fibroblasts (L929) and the Chinese hamster lung (V79-4)) and four tumor cell lines (human breast (MDA-MB-231 and MCF-7), human lung (A549), and human prostate (DU-145)). The results suggest that the Pt-CQ complexes are generally more cytotoxic than the free CQ, showing that they are promising as anticancer drugs. PMID:26606142

  11. Rapid genome wide mapping of phosphine resistance loci by a simple regional averaging analysis in the red flour beetle, Tribolium castaneum

    PubMed Central

    2013-01-01

    Background Next-generation sequencing technology is an important tool for the rapid, genome-wide identification of genetic variations. However, it is difficult to resolve the ‘signal’ of variations of interest and the ‘noise’ of stochastic sequencing and bioinformatic errors in the large datasets that are generated. We report a simple approach to identify regional linkage to a trait that requires only two pools of DNA to be sequenced from progeny of a defined genetic cross (i.e. bulk segregant analysis) at low coverage (<10×) and without parentage assignment of individual SNPs. The analysis relies on regional averaging of pooled SNP frequencies to rapidly scan polymorphisms across the genome for differential regional homozygosity, which is then displayed graphically. Results Progeny from defined genetic crosses of Tribolium castaneum (F4 and F19) segregating for the phosphine resistance trait were exposed to phosphine to select for the resistance trait while the remainders were left unexposed. Next generation sequencing was then carried out on the genomic DNA from each pool of selected and unselected insects from each generation. The reads were mapped against the annotated T. castaneum genome from NCBI (v3.0) and analysed for SNP variations. Since it is difficult to accurately call individual SNP frequencies when the depth of sequence coverage is low, variant frequencies were averaged across larger regions. Results from regional SNP frequency averaging identified two loci, tc_rph1 on chromosome 8 and tc_rph2 on chromosome 9, which together are responsible for high level resistance. Identification of the two loci was possible with only 5-7× average coverage of the genome per dataset. These loci were subsequently confirmed by direct SNP marker analysis and fine-scale mapping. Individually, homozygosity of tc_rph1 or tc_rph2 results in only weak resistance to phosphine (estimated at up to 1.5-2.5× and 3-5× respectively), whereas in combination they interact synergistically to provide a high-level resistance >200×. The tc_rph2 resistance allele resulted in a significant fitness cost relative to the wild type allele in unselected beetles over eighteen generations. Conclusion We have validated the technique of linkage mapping by low-coverage sequencing of progeny from a simple genetic cross. The approach relied on regional averaging of SNP frequencies and was used to successfully identify candidate gene loci for phosphine resistance in T. castaneum. This is a relatively simple and rapid approach to identifying genomic regions associated with traits in defined genetic crosses that does not require any specialised statistical analysis. PMID:24059691

  12. Importance of Intermolecular Hydrogen Bonding for the Stereochemical Control of Allene-Enone (3+2) Annulations Catalyzed by a Bifunctional, Amino Acid Derived Phosphine Catalyst.

    PubMed

    Holland, Mareike C; Gilmour, Ryan; Houk, K N

    2016-02-01

    The origin of stereoselectivity in the (3+2) annulation of allenes and enones catalyzed by an amino acid derived phosphine catalyst has been investigated by the use of dispersion-corrected density functional theory. An intermolecular hydrogen bond between the intermediate zwitterion and the enone was found to be the key interaction in the two enantiomeric transition states. Additional stabilization is provided by intermolecular hydrogen-bonding interactions between acidic positions on the catalyst backbone and the substrate. Enantioselectivity occurs because the intermolecular hydrogen bond in the transition state leading to the minor enantiomer is only possible at the expense of reactant distortion. PMID:26732907

  13. Genetic linkage analysis of the lesser grain borer Rhyzopertha dominica identifies two loci that confer high-level resistance to the fumigant phosphine.

    PubMed Central

    Schlipalius, David I; Cheng, Qiang; Reilly, Paul E B; Collins, Patrick J; Ebert, Paul R

    2002-01-01

    High levels of inheritable resistance to phosphine in Rhyzopertha dominica have recently been detected in Australia and in an effort to isolate the genes responsible for resistance we have used random amplified DNA fingerprinting (RAF) to produce a genetic linkage map of R. dominica. The map consists of 94 dominant DNA markers with an average distance between markers of 4.6 cM and defines nine linkage groups with a total recombination distance of 390.1 cM. We have identified two loci that are responsible for high-level resistance. One provides approximately 50x resistance to phosphine while the other provides 12.5x resistance and in combination, the two genes act synergistically to provide a resistance level 250x greater than that of fully susceptible beetles. The haploid genome size has been determined to be 4.76 x 10(8) bp, resulting in an average physical distance of 1.2 Mbp per map unit. No recombination has been observed between either of the two resistance loci and their adjacent DNA markers in a population of 44 fully resistant F5 individuals, which indicates that the genes are likely to reside within 0.91 cM (1.1 Mbp) of the DNA markers. PMID:12072472

  14. Synthesis of bis(3-{[2-(allyloxy)ethoxy]methyl}-2,4,6-trimethylbenzoyl)(phenyl)phosphine oxide – a tailor-made photoinitiator for dental adhesives

    PubMed Central

    Lamparth, Iris; Angermann, Jörg; Fischer, Urs Karl; Zeuner, Frank; Bock, Thorsten; Liska, Robert; Rheinberger, Volker

    2010-01-01

    Summary Because of the poor solubility of the commercially available bisacylphosphine oxides in dental acidic aqueous primer formulations, bis(3-{[2-(allyloxy)ethoxy]methyl}-2,4,6-trimethylbenzoyl)(phenyl)phosphine oxide (WBAPO) was synthesized starting from 3-(chloromethyl)-2,4,6-trimethylbenzoic acid by the dichlorophosphine route. The substituent was introduced by etherification with 2-(allyloxy)ethanol. In the second step, 3-{[2-(allyloxy)ethoxy]methyl}-2,4,6-trimethylbenzoic acid was chlorinated. The formed acid chloride showed an unexpected low thermal stability. Its thermal rearrangement at 180 °C resulted in a fast formation of 3-(chloromethyl)-2,4,6-trimethylbenzoic acid 2-(allyloxy)ethyl ester. In the third step, the acid chloride was reacted with phenylphosphine dilithium with the formation of bis(3-{[2-(allyloxy)ethoxy]methyl}-2,4,6-trimethylbenzoyl)(phenyl)phosphine, which was oxidized to WBAPO. The structure of WBAPO was confirmed by 1H NMR, 13C NMR, 31P NMR, and IR spectroscopy, as well as elemental analysis. WBAPO, a yellow liquid, possesses improved solubility in polar solvents and shows UV–vis absorption, and a high photoreactivity comparable with the commercially available bisacylphosphine oxides. A sufficient storage stability was found in dental acidic aqueous primer formulations. PMID:20502649

  15. Inorganic heterocyclic bis(phosphines): syntheses and structures of a 1,2-bis(diazasilaphosphetidino)ethane and its nickel, molybdenum, and rhodium complexes.

    PubMed

    Schranz, Ingo; Lief, Graham R; Midstokke, Steven J; Stahl, Lothar

    2002-12-16

    Synthesis and characterization of a new, highly electron-rich, chelating bis(phosphine), based on the ethanediyl-linked inorganic heterocycle [Me(2)Si(mu-N(t)Bu)(2)P], are reported. Treatment of nickel chloride with this bis(phosphine) afforded square-planar cis-[[Me(2)Si(mu-N(t)Bu)(2)PCH(2)](2)NiCl(2)], which features isometric nickel-chloride (2.2220(8) A) and nickel-phosphorus (2.1572(8) A) bonds. The ligand reacted with cis-[(piperidine)(2)Mo(CO)(4)] to form colorless cis-[[Me(2)Si(mu-N(t)Bu)(2)PCH(2)](2)Mo(CO)(4)], which has distorted octahedral geometry and long Mo-P bonds (2.5461(18) A). Because of its potential applications in hydrogenation catalysis cis-[[Me(2)Si(mu-N(t)()Bu)(2)PCH(2)](2)Rh(COD)]BF(4) was synthesized. This square-planar, cationic rhodium(I) complex, having symmetrical Rh-P (2.250(2) A) and Rh-C (2.305(6) A) bonds, is structurally related to bis(phospholano)- and bis(phosphetano)rhodium species. PMID:12470091

  16. Structure-Guided, Single-Point Modifications in the Phosphinic Dipeptide Structure Yield Highly Potent and Selective Inhibitors of Neutral Aminopeptidases

    PubMed Central

    2014-01-01

    Seven crystal structures of alanyl aminopeptidase from Neisseria meningitides (the etiological agent of meningitis, NmAPN) complexed with organophosphorus compounds were resolved to determine the optimal inhibitor–enzyme interactions. The enantiomeric phosphonic acid analogs of Leu and hPhe, which correspond to the P1 amino acid residues of well-processed substrates, were used to assess the impact of the absolute configuration and the stereospecific hydrogen bond network formed between the aminophosphonate polar head and the active site residues on the binding affinity. For the hPhe analog, an imperfect stereochemical complementarity could be overcome by incorporating an appropriate P1 side chain. The constitution of P1′-extended structures was rationally designed and the lead, phosphinic dipeptide hPhePψ[CH2]Phe, was modified in a single position. Introducing a heteroatom/heteroatom-based fragment to either the P1 or P1′ residue required new synthetic pathways. The compounds in the refined structure were low nanomolar and subnanomolar inhibitors of N. meningitides, porcine and human APNs, and the reference leucine aminopeptidase (LAP). The unnatural phosphinic dipeptide analogs exhibited a high affinity for monozinc APNs associated with a reasonable selectivity versus dizinc LAP. Another set of crystal structures containing the NmAPN dipeptide ligand were used to verify and to confirm the predicted binding modes; furthermore, novel contacts, which were promising for inhibitor development, were identified, including a π–π stacking interaction between a pyridine ring and Tyr372. PMID:25192493

  17. The coordination of perrhenate and pertechnetate to thorium(IV) in the presence of phosphine oxide or phosphate ligands.

    PubMed

    Sutton, Andrew D; May, Iain; Sharrad, Clint A; Sarsfield, Mark J; Helliwell, Madeleine

    2006-12-28

    A series of thorium(IV) perrhenato- and pertechnetato-complexes with P[double bond, length as m-dash]O donor ligands have been prepared and characterised both in the solid state and in solution. Isostructural complexes of general formula [Th(MO(4))(4)(L)(4)], where M = Re or Tc and L = triethylphosphate (TEP) (2 and 7), tri-iso-butylphosphate (TiBP) (3 and 8) and tri-n-butylphosphine oxide (TBPO) (4 and 9) have been prepared from the novel starting materials [Th(ReO(4))(4)] x 4H(2)O (1) and [Th(TcO(4))(4)] x 4H(2)O (6). The reaction of or with triphenylphosphine oxide (TPPO) in MeOH has also led to the synthesis of [Th(MO(4))(3)(TPPO)(3)(OCH(3))(HOCH(3))] (M = Re (5) or Tc (10)). While the structural characterisation of 4 and 9 has been previously described, we report for the first time the structural characterisation of 2 and 5, with a partial structural refinement of 3. Vibrational spectroscopic analysis confirms that the Tc complexes not characterised by single crystal X-ray diffraction are indeed isostructural with the perrhenate complexes with the same P[double bond, length as m-dash]O donor ligand. In all cases, monodentate coordination of the Group 7 tetraoxo anion is observed. (31)P NMR spectroscopy indicates that in all the phosphine oxide-based complexes there is one dominant solution species. For the phosphate based systems, the presence of pertechnetate appears to inhibit P[double bond, length as m-dash]O donor ligand complexation in solution, whereas a significant proportion of each phosphate remains coordinated to Th(IV) when perrhenate is present as the counter ligand. These results give some indication as to the mechanism of pertechnetate co-extraction with tetravalent cations in the presence of tri-n-butyl phosphate in the Plutonium and Uranium Recovery by Extraction (PUREX) process. PMID:17146538

  18. Effect of the Phosphine Steric and Electronic Profile on the Rh-Promoted Dehydrocoupling of Phosphine–Boranes

    PubMed Central

    2014-01-01

    The electronic and steric effects in the stoichiometric dehydrocoupling of secondary and primary phosphine–boranes H3B·PR2H [R = 3,5-(CF3)2C6H3; p-(CF3)C6H4; p-(OMe)C6H4; adamantyl, Ad] and H3B·PCyH2 to form the metal-bound linear diboraphosphines H3B·PR2BH2·PR2H and H3B·PRHBH2·PRH2, respectively, are reported. Reaction of [Rh(L)(η6-FC6H5)][BArF4] [L = Ph2P(CH2)3PPh2, ArF = 3,5-(CF3)2C6H3] with 2 equiv of H3B·PR2H affords [Rh(L)(H)(σ,η-PR2BH3)(η1-H3B·PR2H)][BArF4]. These complexes undergo dehydrocoupling to give the diboraphosphine complexes [Rh(L)(H)(σ,η2-PR2·BH2PR2·BH3)][BArF4]. With electron-withdrawing groups on the phosphine–borane there is the parallel formation of the products of B–P cleavage, [Rh(L)(PR2H)2][BArF4], while with electron-donating groups no parallel product is formed. For the bulky, electron rich, H3B·P(Ad)2H no dehydrocoupling is observed, but an intermediate Rh(I) σ phosphine–borane complex is formed, [Rh(L){η2-H3B·P(Ad)2H}][BArF4], that undergoes B–P bond cleavage to give [Rh(L){η1-H3B·P(Ad)2H}{P(Ad)2H}][BArF4]. The relative rates of dehydrocoupling of H3B·PR2H (R = aryl) show that increasingly electron-withdrawing substituents result in faster dehydrocoupling, but also suffer from the formation of the parallel product resulting from P–B bond cleavage. H3B·PCyH2 undergoes a similar dehydrocoupling process, and gives a mixture of stereoisomers of the resulting metal-bound diboraphosphine that arise from activation of the prochiral P–H bonds, with one stereoisomer favored. This diastereomeric mixture may also be biased by use of a chiral phosphine ligand. The selectivity and efficiencies of resulting catalytic dehydrocoupling processes are also briefly discussed. PMID:24617924

  19. Gas-phase ion chemistry and ab initio theoretical study of phosphine. II. Reactions of PH+ with PH3

    NASA Astrophysics Data System (ADS)

    Antoniotti, Paola; Operti, Lorenza; Rabezzana, Roberto; Tonachini, Glauco; Vaglio, Gian Angelo

    1998-12-01

    The gas-phase ion chemistry of phosphine has been investigated by ab initio theoretical calculations and experimental techniques. Following a previous study of H and H2 loss pathways from the 3P-PH3+ adduct (generated by 3P+ reacting with PH3), the quantum chemical study of these processes has been extended to the ion-molecule reactions starting from 2PH+ reacting with PH3, as observed by ion trapping. In these experiments, PH+ reacts to give P2Hn+ (n=2,3) product ions, with loss of H2 or H in different pathways, and also reacts in charge-exchange processes to form PH and PH3+. Moreover, elimination of two hydrogen molecules has been observed leading to the formation of the P2+ ion species. All these processes take place at similar rates, their constants ranging from 1.2 to 5.5×10-10 cm3 molecule-1 s-1. The geometrical structures and energies of transition structures, reaction intermediates, and final products have been determined by ab initio theoretical methods. The initial step is formation of the 2HP-PH3+ adduct. Then, a hydrogen atom can be directly lost either from dicoordinated or tetracoordinated phosphorus, to give 3P-PH3+ or 1HP=PH2+, respectively. Alternatively, one hydrogen can first undergo a displacement from the latter to the former P atom to give 2H2P-PH2+. This migration can then be followed by P-H bond dissociation, yielding again 1HP=PH2+. Dissociation of H2 can also occur, from either the initial HPPH3+ or rearranged H2P-PH2+ isomeric ions, yielding the 2HP=PH+ or 2H2P=P+ ions, respectively. These last species are related by a H-migration process. A last H2 loss from H2P=P+ produces 2P2+. Other pathways were explored, but proved not to be viable. The heats of formation of the P2Hn+ (n=0-4) ionic species have also been computed and reported with the experimental data in the literature.

  20. Design of a Brønsted acid with two different acidic sites: synthesis and application of aryl phosphinic acid-phosphoric acid as a Brønsted acid catalyst.

    PubMed

    Momiyama, N; Narumi, T; Terada, M

    2015-12-11

    A Brønsted acid with two different acidic sites, aryl phosphinic acid-phosphoric acid, has been synthesized. Its catalytic performance was assessed in the hetero-Diels-Alder reaction of aldehyde hydrates with Danishefsky's diene, achieving high reaction efficiency. PMID:26445921

  1. Metal-metal multiply bonded complexes of technetium. 1. Synthesis and structural characterization of phosphine complexes that contain a Tc-Tc multiple bond

    SciTech Connect

    Burns, C.J.; Burrell, A.K.; Cotton, F.A.

    1994-05-11

    A series of triply metal-metal bonded ditechnetium(II) phosphine complexes with the general formula Tc{sub 2}Cl{sub 4}(PR{sub 3}){sub 4} (PR{sub 3} = PEt{sub 3}, PPr{sup n}{sub 3}, PMePh{sub 2}, PMe{sub 2}Ph) have been prepared from mononuclear Tc(IV) precursors and fully characterized. Two-electron reduction of the Tc(IV) bis(phosphine) complexes TcCl{sub 4}(PR{sub 3}){sub 2} (PR{sub 3} = PEt{sub 3}, PPr{sup n}{sub 3}, PMePh{sub 2}, PMe{sub 2}Ph) with finely divided zinc in aromatic solvents or tetrahydrofuran results in the formation of the corresponding electron-rich triply bonded compounds Tc{sub 2}Cl{sub 4}(PR{sub 3}){sub 4} in high yield. These are the first phosphine complexes of technetium that possess a metal-metal bond. The solid-state structures of the PEt{sub 3}, PMe{sub 2}Ph, and PMePh{sub 2} derivatives have been investigated by X-ray crystallography and are described in detail. Similar to the analogous dirhenium(II) complexes, the molecules adopt an eclipsed M{sub 2}L{sub 8} conformation with approximate D{sub 2d} symmetry. The Tc-Tc bond lengths are 2.133(3), 2.127(1), and 2.1384(5) {angstrom} for Tc{sub 2}Cl{sub 4}(PEt{sub 3}){sub 4}, Tc{sub 2}Cl{sub 4}(PEt{sub 3}){sub 4}, Tc{sub 2}Cl{sub 4}(PMe{sub 2}Ph){sub 4}, and Tc{sub 2}Cl{sub 4}(PMePh{sub 2}){sub 4}, respectively. Structural and spectroscopic evidence indicates that these dimers contain an electron-rich Tc-Tc triple bond with a {sigma}{sup 2}-{pi}-{sup 4}{delta}{sup 2}{delta}*{sup 2} ground-state electronic configuration. Electrochemical studies reveal that each compound undergoes two reversible one-electron oxidation processes, which presumably produce the corresponding Tc{sub 2}{sup 5+} and Tc{sub 2}{sup 6+} dinuclear species. {sup 1}H HMR, {sup 31}P({sup 1}H) NMR, and UV-vis spectroscopic data are presented for each compound.

  2. Diverse Tp*-Capped W-Cu-S Clusters from One-Pot Assembly Involving in Situ Thiolation of Phosphines.

    PubMed

    Zhao, Xin; Zhou, Feng; Liu, Quan; Chen, Qiu-Fang; Yang, Jun-Yi; Zhang, Wen-Hua; Song, Ying-Lin; Lang, Jian-Ping

    2016-02-15

    In the absence/presence of S8, the one-pot assembly of [Et4N][Tp*WS3] [1; Tp* = hydridotris(3,5-dimethylpyrazol-1-yl)borate] with [Cu(MeCN)4]PF6 and bis- or tetraphosphine ligands 1,2-bis(diphenylphosphino)ethane (dppe), 1,3-bis(diphenylphosphino)propane (dppp), 1,4-bis(diphenylphosphino)butane (dppb), and N,N,N',N'-tetrakis(diphenylphosphinomethyl)ethylenediamine (dppeda) produces six W-Cu-S clusters, namely, [(Tp*WS3Cu2Cl)2(dppe)] (2), [Tp*WS3Cu4(dppp)2(μ4-Cl)(μ-Cl)]PF6·MeCN (3·MeCN), [(Tp*WS3Cu3)2(μ4-Cl)(μ-Cl)2(dpppS2)] (4), [(Tp*WS3Cu2Cl)2(dppbS2)]·2MeCN·2H2O (5·2MeCN·2H2O), [(Tp*WS3Cu3Cl2)2(dppbS2)] (6), and [(Tp*WS3Cu3)2(Ph2PS2)3(μ6-Cl)0.5](PF6)0.5·0.75CH2Cl2 (7·0.75CH2Cl2). Compounds 2-7 are characterized by elemental analysis, IR, UV-vis, (1)H and (31)P{(1)H} NMR, electrospray ionization mass spectrometry, and X-ray crystallography. For 2, the dppe ligand bridges a pair of butterfly-shaped [Tp*WS3Cu2] cores to form a double-butterfly-shaped structure. For 4, the dppp ligand is susceptible toward S association and forms an in situ generated dpppS2 ligand, supporting an octanuclear double-half-open-cubane structure and contrasting an analogous system wherein a pentanuclear motorcycle-shaped cationic cluster 3 is formed with the absence of S8. A longer dppb ligand readily converts to S-based ligands in 5 and 6, subsequently serving as bridges between a pair of a butterfly-shaped (5) and nest-shaped (6) clusters. Further use of a tetraphosphine ligand, dppeda, in the cluster formation, with the presence of S8, leads to an unexpected ligand degradation to give the [Ph2PS2](-) anions. Three [Ph2PS2](-) anions juxtapose a pair of nest-shaped cluster cores to yield an octanuclear cluster, 7, featuring a cage to encapsulate μ6-Cl(-). The third-order nonlinear-optical (NLO) properties of 2-7 in N,N-dimethylformamide, investigated using a Z-scan technique at 532 nm, show that 2-6 have a reverse saturable absorption, while 7 has a notable saturable absorption. All of 2-7 exhibit a self-focusing effect with hyperpolarizability γ values in the range of 4.71 × 10(-30)-1.02 × 10(-29) esu, which are 440-1000 times higher than that of 1. The formation of 4-7 from 1 through the in situ thiolation of phosphine ligands presents a new approach to the design and assembly of the W-Cu-S clusters with interesting structural arrays and better NLO properties. PMID:26811914

  3. Aspects of the cleavage of phosphines with potassium: Synthesis and reactivity of lithium and potassium bis(p-(dimethylamino)phenyl)phosphide

    SciTech Connect

    Toth, I.; Hanson, B.E.; Davis, M.E. )

    1990-03-01

    The cleavage of the triarylphosphines P(p-C{sub 6}H{sub 4}NMe{sub 2}){sub 3} and PhP(p-C{sub 6}H{sub 4}NMe{sub 2}){sub 2} with potassium in ether solvents was found to occur at room temperature. Cleavage of the mixed phosphine PhP(p-C{sub 6}H{sub 4}NMe{sub 2}){sub 2} was found to give a mixture of products that reflects the relative stability of the phosphides KP(Ph)(p-C{sub 6}H{sub 4}NMe{sub 2}) and KP(p-C{sub 6}H{sub 4}NMe{sub 2}){sub 2}. Cleavage with lithium resulted in the scrambling of the aryl groups so that the products LiPPh{sub 2} and P(Ph){sub 2}(p-C{sub 6}H{sub 4}NMe{sub 2}) also were obtained.

  4. Phosphine-Catalyzed Doubly Stereoconvergent ?-Additions of Racemic Heterocycles to Racemic Allenoates: The Catalytic Enantioselective Synthesis of Protected ?,?-Disubstituted ?-Amino Acid Derivatives

    PubMed Central

    2015-01-01

    Methods have recently been developed for the phosphine-catalyzed asymmetric ?-addition of nucleophiles to readily available allenoates and alkynoates to generate useful ?,?-unsaturated carbonyl compounds that bear a stereogenic center in either the ? or the ? position (but not both) with high stereoselectivity. The utility of this approach would be enhanced considerably if the stereochemistry at both termini of the new bond could be controlled effectively. In this report, we describe the achievement of this objective, specifically, that a chiral phosphepine can catalyze the stereoconvergent ?-addition of a racemic nucleophile to a racemic electrophile; through the choice of an appropriate heterocycle as the nucleophilic partner, this new method enables the synthesis of protected ?,?-disubstituted ?-amino acid derivatives in good yield, diastereoselectivity, and enantioselectivity. PMID:26192217

  5. A totally phosphine-free synthesis of metal telluride nanocrystals by employing alkylamides to replace alkylphosphines for preparing highly reactive tellurium precursors.

    PubMed

    Yao, Dong; Liu, Yi; Zhao, Wujun; Wei, Haotong; Luo, Xintao; Wu, Zhennan; Dong, Chunwei; Zhang, Hao; Yang, Bai

    2013-10-21

    Despite the developments in the wet chemical synthesis of high-quality semiconductor nanocrystals (NCs) with diverse elemental compositions, telluride NCs are still irreplaceable materials owing to their excellent photovoltaic and thermoelectric performances. Herein we demonstrate the dissolution of elemental tellurium (Te) in a series of alkylamides by sodium borohydride (NaBH4) reduction at relatively low temperature to produce highly reactive precursors for hot-injection synthesis of telluride NCs. The capability to tune the reactivity of Te precursors by selecting injection temperature permits control of NC size over a broad range. The current preparation of Te precursors is simple, economical, and totally phosphine-free, which will promote the commercial synthesis and applications of telluride NCs. PMID:24056800

  6. Isomorphism in the structural chemistry of two-coordinate adducts of diphenyl(2-formylphenyl)phosphine and triphenylphosphine with gold(I) halides

    NASA Astrophysics Data System (ADS)

    Dunstan, Samuel P. C.; Healy, Peter C.; Sobolev, Alexandre N.; Tiekink, Edward R. T.; White, Allan H.; Williams, Michael L.

    2014-08-01

    Single crystal X-ray structure determinations are recorded for diphenyl(2-formylphenyl)phosphine gold(I) halides [Ph2(Ph-CHO)PAuX], X = Cl, Br and I, and for redeterminations of enhanced precision for triphenylphosphine gold(I) halides [Ph3PAuX], X = Cl, Br, I, and SCN0.91Br0.09. These complexes, other than [Ph2(Ph-CHO)PAuCl], together with a diverse array of other structures, crystallize as an isomorphous series in the orthorhombic space group P212121a = 9.804(1)-11.906(3), b = 11.771(2)-12.996(3) and c = 12.871(1)-14.169(3) . In these complexes, introduction of the formyl group results in only minor differences between the conformations of the two phosphine ligands and the corresponding Au-P, Au-X, and Au-P-X bond lengths and angles. The crystal packings of [Ph3PAuX] for X = Cl, Br, I and of [Ph2(Ph-CHO)PAuX] for X = Br and I show that, while these structures are isomorphous, different supramolecular synthons may be present, suggesting global packing considerations are all-important rather than specific supramolecular interactions. This is borne out by the different packing found for the centrosymmetric [Ph2(Ph-CHO)PAuCl] structure. Crystallization of the mixed anion structure [Ph3PAuSCN0.91Br0.09] in the above P212121 lattice rather than the P21/c lattice reported for pure [Ph3PAuSCN] suggests that co-crystallization with bromide may impose constraints on packing considerations which favor crystallization in the P212121 lattice.

  7. A totally phosphine-free synthesis of metal telluride nanocrystals by employing alkylamides to replace alkylphosphines for preparing highly reactive tellurium precursors

    NASA Astrophysics Data System (ADS)

    Yao, Dong; Liu, Yi; Zhao, Wujun; Wei, Haotong; Luo, Xintao; Wu, Zhennan; Dong, Chunwei; Zhang, Hao; Yang, Bai

    2013-09-01

    Despite the developments in the wet chemical synthesis of high-quality semiconductor nanocrystals (NCs) with diverse elemental compositions, telluride NCs are still irreplaceable materials owing to their excellent photovoltaic and thermoelectric performances. Herein we demonstrate the dissolution of elemental tellurium (Te) in a series of alkylamides by sodium borohydride (NaBH4) reduction at relatively low temperature to produce highly reactive precursors for hot-injection synthesis of telluride NCs. The capability to tune the reactivity of Te precursors by selecting injection temperature permits control of NC size over a broad range. The current preparation of Te precursors is simple, economical, and totally phosphine-free, which will promote the commercial synthesis and applications of telluride NCs.Despite the developments in the wet chemical synthesis of high-quality semiconductor nanocrystals (NCs) with diverse elemental compositions, telluride NCs are still irreplaceable materials owing to their excellent photovoltaic and thermoelectric performances. Herein we demonstrate the dissolution of elemental tellurium (Te) in a series of alkylamides by sodium borohydride (NaBH4) reduction at relatively low temperature to produce highly reactive precursors for hot-injection synthesis of telluride NCs. The capability to tune the reactivity of Te precursors by selecting injection temperature permits control of NC size over a broad range. The current preparation of Te precursors is simple, economical, and totally phosphine-free, which will promote the commercial synthesis and applications of telluride NCs. Electronic supplementary information (ESI) available: Detailed experimental procedure, and additional characterization of CdTe, HgTe, PbTe and Ag7Te4 NCs. See DOI: 10.1039/c3nr03553k

  8. Gas phase monitoring of reactions under InP MOVPE growth conditions for the decomposition of tertiarybutyl phosphine and related precursors

    NASA Astrophysics Data System (ADS)

    Fan, G. H.; Hoare, R. D.; Pemble, M. E.; Povey, I. M.; Taylor, A. G.; Williams, J. O.

    1992-11-01

    Ex-situ Fourier transform infrared spectroscopy has been used to study the decomposition of tertiarybutylphosphine (TBP), trimethylindium (TMIn) and mixtures of TBP and TMIn under MOCVD conditions using dihydrogen as a carrier gas. IR bands due to TBP, TMIn, phosphine, isobutene, isobutane, ethene and methane have been monitored as a function of susceptor temperature. The decomposition of TBP alone in dihydrogen is observed to commence at temperatures above 773 K and is accompanied by the formation of isobutene, phosphine and isobutane. The pyrolysis of TBP is observed to be complete at temperatures in excess of 973 K. For TMIn in dihydrogen, the only observable product at temperatures greater than 573 K is methane. For TBP in the presence of TMIn a room temperature reaction is observed, the only detachable product of which is methane. The implication is that TMIn reacts in some way with TBP, possibly forming an "adduct" or polymer; however, decomposition products from TBP are not observed until temperatures are in excess of 573 K, while decomposition is observed to be complete at temperatures of 873 K. Once again isobutene, isobutane and phospine formation accompanies the TBP decomposition at 573K. At temperatures in excess of 900 K, both methane and ethene were observed during both of these experiments and are assumed to arise via the decomposition of isobutene. The deposited product on the reactor wall was found to be InP and phosphorus (rhombohedral) by X-ray diffraction. Some mechanistic steps for these reactions are proposed. In addition, preliminary data for the decomposition of cyclohexylphosphine are presented.

  9. Divergence in the reactivity between amine- and phosphine-catalyzed cycloaddition reactions of allenoates with enynals: one-pot gold-catalyzed synthesis of trisubstituted benzofurans from the [3 + 2] cycloadduct via 1,2-alkyl migration and dehydrogenation.

    PubMed

    Kumari, A Leela Siva; Swamy, K C Kumara

    2015-04-17

    Regioselective synthesis of functionalized dihydropyran derivatives by DABCO-catalyzed [2 + 4] cycloaddition of allenoates with enynals or enynones has been developed. Phosphine-catalyzed [3 + 2] cycloaddition of allenoates with enynals provides 1,1-alkyne (aldehyde)-substituted cyclopentenes wherein enynals act as electrophiles. These alkyne-tethered cyclopentenes upon [Au]/[Ag] catalysis lead to substituted benzofurans via 1,2-alkyl migration and dehydrogenation (aromatization). One-pot reaction of allenoates with enynals using sequential phosphine and gold catalysis is also reported. The cyclopentene obtained from the PPh3-catalyzed reaction of allenoate H2C═C═CH(COO-t-Bu) with enynal undergoes decarboxylation under the [Au]/[Ag] catalysis and forms a carboxylate-free benzofuran. The structures of key products are confirmed by single-crystal X-ray analysis. PMID:25793444

  10. Extraction mechanism of Sc(III) and separation from Th(IV), Fe(III) and Lu(III) with bis(2,4,4-trimethylpentyl)phosphinic acid in n-hexane from sulphuric acid solutions

    SciTech Connect

    Wang, Chun; Li, Deqian )

    1994-06-01

    The extraction equilibrium data of sulphuric acid and scandium(III) with bis(2,4,4-trimethylpentyl)phosphinic acid (H[BTMPP]) from sulphuric acid solutions have been obtained. There are two extraction mechanisms of scandium(III) with H[BTMPP] at different ranges of aqueous acidity. The extraction of Sc(III) proceeds according to a cation exchange reaction at lower aqueous acidity and to a solvating reaction at higher acidity. The practicability of separating Sc(III) from Th(IV),Fe(III) and Lu(III) by controlling the aqueous acidity was discussed. The effect of temperature on extraction of Sc(III) was observed and thermodynamic functions were calculated. IR and NMR spectra were made for organic extracts. The extraction characteristics of H[BTMPP] and di(2-ethylhexyl)phosphinic acid (H[DEHP]) were contrasted to obtain more information about extraction with H[BTMPP]. 12 refs., 6 figs., 1 tab.

  11. (Benzyl-diphenyl-phosphine-3κP)[μ-bis(diphenyl-arsino)methane-1:2κAs:As']nona-carbonyl-1κC,2κC,3κC-triangulo-triruthenium(0).

    PubMed

    Shawkataly, Omar Bin; Khan, Imthyaz Ahmed; Yeap, Chin Sing; Fun, Hoong-Kun

    2009-01-01

    The asymmetric unit of the title triangulo-triruthenium compound, [Ru(3)(C(25)H(22)As(2))(C(19)H(17)P)(CO)(9)], consists of two crystallographically independent mol-ecules of the triangulo-triruthenium complex, A and B. The bis-(diphenyl-arsino)methane ligand bridges an Ru-Ru bond and the monodentate phosphine ligand bonds to the third Ru atom. Both the phosphine and arsine ligands are equatorial with respect to the Ru(3) triangle. In addition, each Ru atom carries one equatorial and two axial terminal carbonyl ligands. With regard to the three phosphine-substituted rings, the benzyl ring makes dihedral angles of 41.0 (3) and 43.9 (3)° with the other two benzene rings in mol-ecule A; these angles are 49.8 (3) and 56.8 (3)° in mol-ecule B. The dihedral angles between the two benzene rings are 76.1 (3) and 88.2 (3)° for the two diphenyl-arsino groups in mol-ecule A and 71.3 (3) and 78.1 (3)° in mol-ecule B. In the crystal packing, mol-ecules are linked into chains via inter-molecular C-H⋯O hydrogen bonds. Weak inter-molecular C-H⋯π inter-actions further stabilize the crystal structure. PMID:21579968

  12. Reactivity of the latent 12-electron fragment [Rh(PiBu3)2]+ with aryl bromides: aryl-Br and phosphine ligand C-H activation.

    PubMed

    Townsend, Nell S; Chaplin, Adrian B; Abu Naser, M; Thompson, Amber L; Rees, Nicholas H; Macgregor, Stuart A; Weller, Andrew S

    2010-07-26

    Oxidative addition of aryl bromides to 12-electron [Rh(PiBu(3))(2)][BAr(F)(4)] (Ar(F)=3,5-(CF(3))(2)C(6)H(3)) forms a variety of products. With p-tolyl bromides, Rh(III) dimeric complexes result [Rh(PiBu(3))(2)(o/p-MeC(6)H(4))(mu-Br)](2)[BAr(F)(4)](2). Similarly, reaction with p-ClC(6)H(4)Br gives [Rh(PiBu(3))(2)(p-ClC(6)H(4))(mu-Br)](2)[BAr(F)(4)](2). In contrast, the use of o-BrC(6)H(4)Me leads to a product in which toluene has been eliminated and an isobutyl phosphine has undergone C-H activation: [Rh{PiBu(2)(CH(2)CHCH(3)CH(2))}(PiBu(3))(mu-Br)](2)[BAr(F)(4)](2). Trapping experiments with ortho-bromo anisole or ortho-bromo thioanisole indicate that a possible intermediate for this process is a low-coordinate Rh(III) complex that then undergoes C-H activation. The anisole and thioanisole complexes have been isolated and their structures show OMe or SMe interactions with the metal centre alongside supporting agostic interactions, [Rh(PiBu(3))(2)(C(6)H(4)OMe)Br][BAr(F)(4)] (the solid-state structure of the 5-methyl substituted analogue is reported) and [Rh(PiBu(3))(2)(C(6)H(4)SMe)Br][BAr(F)(4)]. The anisole-derived complex proceeds to give [Rh{PiBu(2)(CH(2)CHCH(3)CH(2))}(PiBu(3))(mu-Br)](2)[BAr(F)(4)](2), whereas the thioanisole complex is unreactive. The isolation of [Rh(PiBu(3))(2)(C(6)H(4)OMe)Br][BAr(F)(4)] and its onward reactivity to give the products of C-H activation and aryl elimination suggest that it is implicated on the pathway of a sigma-bond metathesis reaction, a hypothesis strengthened by DFT calculations. Calculations also suggest that C-H bond cleavage through phosphine-assisted deprotonation of a non-agostic bond is also competitive, although the subsequent protonation of the aryl ligand is too high in energy to account for product formation. C-H activation through oxidative addition is also ruled out on the basis of these calculations. These new complexes have been characterised by solution NMR/ESIMS techniques and in the solid-state by X-ray crystallography. PMID:20572181

  13. Cyclam Derivatives with a Bis(phosphinate) or a Phosphinato-Phosphonate Pendant Arm: Ligands for Fast and Efficient Copper(II) Complexation for Nuclear Medical Applications.

    PubMed

    David, Tomáš; Kubíček, Vojtěch; Gutten, Ondrej; Lubal, Přemysl; Kotek, Jan; Pietzsch, Hans-Jürgen; Rulíšek, Lubomír; Hermann, Petr

    2015-12-21

    Cyclam derivatives bearing one geminal bis(phosphinic acid), -CH2PO2HCH2PO2H2 (H2L(1)), or phosphinic-phosphonic acid, -CH2PO2HCH2PO3H2 (H3L(2)), pendant arm were synthesized and studied as potential copper(II) chelators for nuclear medical applications. The ligands showed good selectivity for copper(II) over zinc(II) and nickel(II) ions (log KCuL = 25.8 and 27.7 for H2L(1) and H3L(2), respectively). Kinetic study revealed an unusual three-step complex formation mechanism. The initial equilibrium step leads to out-of-cage complexes with Cu(2+) bound by the phosphorus-containing pendant arm. These species quickly rearrange to an in-cage complex with cyclam conformation II, which isomerizes to another in-cage complex with cyclam conformation I. The first in-cage complex is quantitatively formed in seconds (pH ≈5, 25 °C, Cu:L = 1:1, cM ≈ 1 mM). At pH >12, I isomers undergo nitrogen atom inversion, leading to III isomers; the structure of the III-[Cu(HL(2))] complex in the solid state was confirmed by X-ray diffraction analysis. In an alkaline solution, interconversion of the I and III isomers is mutual, leading to the same equilibrium isomeric mixture; such behavior has been observed here for the first time for copper(II) complexes of cyclam derivatives. Quantum-chemical calculations showed small energetic differences between the isomeric complexes of H3L(2) compared with analogous data for isomeric complexes of cyclam derivatives with one or two methylphosphonic acid pendant arm(s). Acid-assisted dissociation proved the kinetic inertness of the complexes. Preliminary radiolabeling of H2L(1) and H3L(2) with (64)Cu was fast and efficient, even at room temperature, giving specific activities of around 70 GBq of (64)Cu per 1 μmol of the ligand (pH 6.2, 10 min, ca. 90 equiv of the ligand). These specific activities were much higher than those of H3nota and H4dota complexes prepared under identical conditions. The rare combination of simple ligand synthesis, very fast copper(II) complex formation, high thermodynamic stability, kinetic inertness, efficient radiolabeling, and expected low bone tissue affinity makes such ligands suitably predisposed to serve as chelators of copper radioisotopes in nuclear medicine. PMID:26615961

  14. Production of Galactooligosaccharides Using β-Galactosidase Immobilized on Chitosan-Coated Magnetic Nanoparticles with Tris(hydroxymethyl)phosphine as an Optional Coupling Agent

    PubMed Central

    Chen, Su-Ching; Duan, Kow-Jen

    2015-01-01

    β-Galactosidase was immobilized on chitosan-coated magnetic Fe3O4 nanoparticles and was used to produce galactooligosaccharides (GOS) from lactose. Immobilized enzyme was prepared with or without the coupling agent, tris(hydroxymethyl)phosphine (THP). The two immobilized systems and the free enzyme achieved their maximum activity at pH 6.0 with an optimal temperature of 50 °C. The immobilized enzymes showed higher activities at a wider range of temperatures and pH. Furthermore, the immobilized enzyme coupled with THP showed higher thermal stability than that without THP. However, activity retention of batchwise reactions was similar for both immobilized systems. All the three enzyme systems produced GOS compound with similar concentration profiles, with a maximum GOS yield of 50.5% from 36% (w·v−1) lactose on a dry weight basis. The chitosan-coated magnetic Fe3O4 nanoparticles can be regenerated using a desorption/re-adsorption process described in this study. PMID:26047337

  15. Halloysite-nanotubes supported FeNi alloy nanoparticles for catalytic decomposition of toxic phosphine gas into yellow phosphorus and hydrogen.

    PubMed

    Tang, Xuejiao; Li, Lili; Shen, Boxiong; Wang, Chengjun

    2013-05-01

    The FeNi alloy nanoparticles (FeNi and BFeNi) supported on natural halloysite nanotubes (HNTs) were prepared for catalytic decomposition of toxic phosphine (PH?) to yellow phosphorus and hydrogen. The Fourier transform infrared spectroscopy, X-ray diffraction, inductively coupled plasma, scanning electron microscope, and hydrogen temperature-programmed reduction tests were carried out to characterize the physicochemical properties of HNTs and the prepared nano-catalysts. Nearly 100% PH? was decomposed into yellow phosphorus and hydrogen at 420 C with prepared FeNi/HNTs catalysts. Metallic Ni and Fe?O? could be the catalytic active sites in FeNi/HNTs for PH? decomposition under the low temperature. The boron (B) additives decrease the catalytic activity of FeNi/HNTs for PH? decomposition due to the formation of the spinal NiFe?O? and Fe?B which replace the active Fe?O? and metallic Ni in catalysts. The developed FeNi/HNTs are low-cost and effective catalysts for air-pollution control and recycle of the hazardous waste PH? gas in industry. PMID:23490180

  16. A phosphine gold(I) pi-alkyne complex: tuning the metal-alkyne bond character and counterion position by the choice of the ancillary ligand.

    PubMed

    Zuccaccia, Daniele; Belpassi, Leonardo; Rocchigiani, Luca; Tarantelli, Francesco; Macchioni, Alceo

    2010-04-01

    The intra- and interionic structures of a mononuclear phosphine gold(I) alkyne complex [(PAr(F)(3))Au(2-hexyne)]BF(4) [1BF(4); Ar(F) = 3,5-bis(trifluoromethyl)phenyl] and its analogous complex [(NHC)Au(2-hexyne)]BF(4) [2BF(4); NHC = 1,3-bis(diisopropylphenyl)imidazol-2-ylidene] have been investigated by combining 1D and 2D multinuclear NMR spectroscopy and density functional theory calculations. It has been found that alkyne in 1BF(4) is depleted of its electron density to a greater extent than that in 2BF(4). This correlates with the Deltadelta((13)C) NMR of the carbon-carbon triple bond. Instead, 2BF(4) is much more "kinetically stable" than 1BF(4). (19)F-(1)H HOESY NMR experiments indicate that the counterion locates close to the gold atom in 1BF(4) (differently from that previously observed in the few other gold(I) ion pairs studied), exactly where the computed Coulomb potential indicates that partial positive charge accumulates. PMID:20222666

  17. Collaborative flowsheet development studies using cobalt dicarbollide and phosphine oxide for the partitioning of radionuclides from Idaho Chemical Processing Plant high-activity liquid waste with centrifugal contactors

    SciTech Connect

    Law, J.D.; Herbst, R.S.; Todd, T.A.

    1996-12-31

    Two solvent extraction technologies under development in Russia for the partitioning of radionuclides from radioactive wastes were tested at the Idaho Chemical Processing Plant (ICPP) with simulated high-activity liquid waste (HAW) on a continuous basis using 24 stages of 2-cm diameter centrifugal contactors. Two flowsheet tests were conducted with chlorinated cobalt dicarbollide (ChCoDiC) to evaluate the separation of cesium and strontium from ICPP HAW. Also, a flowsheet test was performed with a derivative of phosphine oxide (POR) to evaluate the separation of actinides, rare earths, and technetium from ICPP HAW. All experiments utilized a non-radioactive HAW simulant prepared to emulate the macro (or matrix) constituents of actual ICPP HAW at their average tank composition. The behavior of the species of interest was monitored using the stable forms of Sr and Cs, europium as a surrogate for americium, and rhenium as a surrogate for technetium. Removal efficiencies and distribution coefficients were determined for each flowsheet at steady-state conditions. Results of this testing indicate the POR and ChCoDiC processes can be used to effectively treat ICPP HAW. This series of tests is a continuation of ongoing efforts to evaluate the applicability of these Russian developed technologies to U.S. nuclear wastes under the auspices of a joint program between the U.S. Department of Energy and the Russian Ministry of Atomic Energy.

  18. Exponential Sum Absorption Coefficients of Phosphine from 2750 to 3550/cm for Application to Radiative Transfer Analyses on Jupiter and Saturn

    NASA Technical Reports Server (NTRS)

    Temma, T.; Baines, K. H.; Butler, R. A. H.; Brown, L. R.; Sagui, L.; Kleiner, I.

    2006-01-01

    PH3 exponential sum k coefficients were computed between 2750 and 3550/cm (2.82-3.64 (microns), in view of future application to radiative transfer analyses of Jupiter and Saturn in a phosphine absorption band near 3 microns. The temperature and pressure of this data set cover the ranges from 80 to 350 K and from 10 (exp -3)to 10(exp 1) bars, respectively. Transmission uncertainty incurred by the use of the k coefficients is smaller than a few percent as long as the radiation is confined above an altitude of a few bars in the giant planets. In spectral regions of weak absorption at high pressures close to 10 bars, contributions from far wings of strong absorption lines must be carefully taken into account. Our data set helps map the three-dimensional distribution of PH3 on the giant planets, revealing their global atmospheric dynamics extending down to the deep interior. The complete k coefficient data set of this work is available at the Web site of the NASA Planetary Data System Atmospheres Node.

  19. Octahedral metal carbonyls. 62. The mechanism of piperidine (pip) displacement by phosphines and phosphites (L') from cis-(pip)(L)W(CO)/sub 4/ complexes in chlorobenzene

    SciTech Connect

    Asali, K.J.; Basson, S.S.; Tucker, J.S.; Hester, B.C.; Cortes, J.E.; Awad, H.H.; Dobson, G.R.

    1987-09-02

    Parallel thermal and pulsed laser flash photolysis studies of cis-(pip)(L)W(CO)/sub 4/ complexes (pip = piperidine; L = phosphines and phosphites) in their reactions with L' in chlorobenzene (CB) solvent and in CB/CH mixtures (CH = cyclohexane) indicate these reactions to proceed via reversible fission of the W-pip bond to produce square-pyramidal ((L)W(CO)/sub 4/) intermediates in which L occupies a position in the equatorial plane. These species undergo very rapid competitive reaction with pip, with L', and with CB to afford, ultimately, the thermally stable cis-(L')(L)W(CO)/sub 4/ products, which may undergo subsequent isomerization. The competition ratios for reactions of chlorobenzene, pip, and L' with ((L)W(CO)/sub 5/) have been measured photochemically and/or thermally, and these ratios have assisted in the identification of cis-((CB)(L)W(CO)/sub 4/), in which CB functions as a coordinating ligand, as the predominant species formed after photolysis. Rate constants and activation parameters for most steps in the ligand-substitution process are reported and are discussed in terms of the steric and electronic properties of both coordinated L, incoming L', and solvent.

  20. On-line preconcentration with a novel alkyl phosphinic acid extraction resin coupled with inductively coupled plasma mass spectrometry for determination of trace rare earth elements in seawater.

    PubMed

    Fu, Qiang; Yang, Limin; Wang, Qiuquan

    2007-06-15

    A newly synthesized alkyl phosphinic acid resin (APAR) was used for on-line preconcentration of trace rare earth elements (REES, lanthanides including yttrium) and then determined by inductively coupled plasma mass spectrometry. REEs in seawater could be on-line concentrated on the APAR packed column (4.6mm i.d.x50mm in length), and eluted from the column with 0.5mL 0.1molL(-1) nitric acid within 30s. An enrichment factor of nearly 400 was achieved for all REEs when the seawater sample volume was 200mL, while the matrix and coexisting spectrally interfering ions such as barium, tin and antimony could be simultaneously separated. The detection limits of this proposed method for REEs were in the range from 1.43pgL(-1) of holmium to 12.7pgL(-1) of lanthanum. The recoveries of REEs were higher than 97.9%, and the precision of the relative standard deviation (R.S.D., n=6) was less than 5%. The method has been applied to the determination of soluble REEs in seawater. PMID:19071752

  1. Effects of phosphine on structure and reductive elimination reactions of (C sub 5 Me sub 5 )Rh(PR sub 3 )PhH complexes

    SciTech Connect

    Jones, W.D.; Kuykendall, V.L. )

    1991-06-12

    The complexes (C{sub 5}Me{sub 5})Rh(PR{sub 3})X{sub 2}, (C{sub 5}Me{sub 5})Rh(PR{sub 3})PhX, (C{sub 5}Me{sub 5})Rh(PR{sub 3})PhH, and (C{sub 5}Me{sub 5})Rh(PR{sub 3})H{sub 2} have been prepared for several members of the series where X = Cl or Br and PR{sub 3} = PPh{sub 3}, PMe{sub 2}Ph, PMe{sub 3}, PMe{sub 2}(t-Bu), PMe{sub 2}(n-Bu), or P(n-Bu){sub 3}. The rates at which the phenyl hydride complexes reductively eliminate benzene have been measured. Four members of the series have been structurally characterizeed, and a comparison is made between the steric and electronic requirements of the phosphine and the rate of benzene elimination, showing the importance of both effects. The crystal structures for the different complexes are reported. 14 refs., 5 figs., 6 tabs.

  2. A structural insight into the P1S1 binding mode of diaminoethylphosphonic and phosphinic acids, selective inhibitors of alanine aminopeptidases.

    PubMed

    Węglarz-Tomczak, Ewelina; Berlicki, Łukasz; Pawełczak, Małgorzata; Nocek, Bogusław; Joachimiak, Andrzej; Mucha, Artur

    2016-07-19

    N'-substituted 1,2-diaminoethylphosphonic acids and 1,2-diaminoethylphosphinic dipeptides were explored to unveil the structural context of the unexpected selectivity of these inhibitors of M1 alanine aminopeptidases (APNs) versus M17 leucine aminopeptidase (LAP). The diaminophosphonic acids were obtained via aziridines in an improved synthetic procedure that was further expanded for the phosphinic pseudodipeptide system. The inhibitory activity, measured for three M1 and one M17 metalloaminopeptidases of different sources (bacterial, human and porcine), revealed several potent compounds (e.g., Ki = 65 nM of 1u for HsAPN). Two structures of an M1 representative (APN from Neisseria meningitidis) in complex with N-benzyl-1,2-diaminoethylphosphonic acid and N-cyclohexyl-1,2-diaminoethylphosphonic acid were determined by the X-ray crystallography. The analysis of these structures and the models of the phosphonic acid complexes of the human ortholog provided an insight into the role of the additional amino group and the hydrophobic substituents of the ligands within the S1 active site region. PMID:27100031

  3. Determination of phosphine and other fumigants in air samples by thermal desorption and 2D heart-cutting gas chromatography with synchronous SIM/Scan mass spectrometry and flame photometric detection.

    PubMed

    Fahrenholtz, Svea; Hühnerfuss, Heinrich; Baur, Xaver; Budnik, Lygia Therese

    2010-12-24

    Fumigants and volatile industrial chemicals are particularly hazardous to health when a freight container is fumigated or the contaminated material is introduced into its enclosed environment. Phosphine is now increasingly used as a fumigant, after bromomethane--the former fumigant of choice--has been banned by the Montreal Protocol. We have enhanced our previously established thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS) method by integrating a second gas chromatographic dimension and a flame photometric detector to allow the simultaneous detection of phosphine and volatile organic compounds (VOCs), providing a novel application. A thermal desorption system is coupled to a two dimensional gas chromatograph using both mass spectrometric and flame photometric detection (TD-2D-GC-MS/FPD). Additionally, the collection of mass spectrometric SIM and Scan data has been synchronised, so only a single analysis is now sufficient for qualitative scanning of the whole sample and for sensitive quantification. Though detection limits for the herewith described method are slightly higher than in the previous method, they are in the low μL m(-3) range, which is not only below the respective occupational exposure and intervention limits but also allows the detection of residual contamination after ventilation. The method was developed for the separation and identification of 44 volatile substances. For 12 of these compounds (bromomethane, iodomethane, dichloromethane, 1,2-dichlorethane, benzene, tetrachloromethane, 1,2-dichloropropane, toluene, trichloronitromethane, ethyl benzene, phosphine, carbon disulfide) the method was validated as we chose the target compounds due to their relevance in freight container handling. PMID:21084090

  4. [μ-Bis(diphenyl-arsino)methane-1:2κAs:As']nona-carbonyl-1κC,2κC,3κC-tricyclo-hexyl-phosphine-3κP-triangulo-triruthenium(0).

    PubMed

    Shawkataly, Omar Bin; Khan, Imthyaz Ahmed; Yeap, Chin Sing; Fun, Hoong-Kun

    2009-01-01

    In the title triangulo-triruthenium compound, [Ru(3)(C(25)H(22)As(2))(C(18)H(33)P)(CO)(9)], the bis-(diphenyl-arsino)methane ligand bridges an Ru-Ru bond and the monodentate phosphine ligand bonds to the third Ru atom. Both the phosphine and arsine ligands are equatorial with respect to the Ru(3) triangle. In addition, each Ru atom carries one equatorial and two axial terminal carbonyl ligands. All three cyclo-hexane rings are disordered over two positions with site occupancies of 0.628 (6) and 0.372 (6). The mean planes of these three phosphine-substituted cyclo-hexane rings make dihedral angles of 53.0 (8), 68.3 (6) and 89.9 (7)° (major components), and 46.7 (14), 41.3 (11) and 75.8 (10)° (minor components) with each other. The dihedral angles between the two phenyl rings are 85.0 (2) and 88.1 (2)° for the two diphenyl-arsino groups. Two cyclo-hexane rings adopt a chair conformation whereas the other adopts a slightly twisted chair conformation for the major components; these conformations are similiar for the minor components. Intra-molecular C-H⋯O hydrogen bonds stabilize the mol-ecular structure. In the crystal packing, the mol-ecules are linked together into chains via inter-molecular C-H⋯O hydrogen bonds down the a axis. Weak inter-molecular C-H⋯π inter-actions further stabilize the crystal structure. PMID:21578646

  5. Potent suppression of Kv1.3 potassium channel and IL-2 secretion by diphenyl phosphine oxide-1 in human T cells.

    PubMed

    Zhao, Ning; Dong, Qian; Du, Li-Li; Fu, Xiao-Xing; Du, Yi-Mei; Liao, Yu-Hua

    2013-01-01

    Diphenyl phosphine oxide-1 (DPO-1) is a potent Kv1.5 channel inhibitor that has therapeutic potential for the treatment of atrial fibrillation. Many other Kv1.5 channel blockers also potently inhibit the Kv1.3 channel, but whether DPO-1 blocks Kv1.3 channels has not been investigated. The Kv1.3 channel is highly expressed in activated T cells, which is considered a favorable target for immunomodulation. Accordingly, we hypothesized that DPO-1 may exert immunosuppressive and anti-inflammatory effects by inhibiting Kv1.3 channel activity. In this study, DPO-1 blocked Kv1.3 current in a voltage-dependent and concentration-dependent manner, with IC₅₀ values of 2.58 µM in Jurkat cells and 3.11 µM in human peripheral blood T cells. DPO-1 also accelerated the inactivation rate and negatively shifted steady-state inactivation. Moreover, DPO-1 at 3 µM had no apparent effect on the Ca²⁺ activated potassium channel (K(Ca)) current in both Jurkat cells and human peripheral blood T cells. In Jurkat cells, pre-treatment with DPO-1 for 24 h decreased Kv1.3 current density, and protein expression by 48±6% and 60±9%, at 3 and 10 µM, respectively (both p<0.05). In addition, Ca²⁺ influx to Ca²⁺-depleted cells was blunted and IL-2 production was also reduced in activated Jurkat cells. IL-2 secretion was also inhibited by the Kv1.3 inhibitors margatoxin and charybdotoxin. Our results demonstrate for the first time that that DPO-1, at clinically relevant concentrations, blocks Kv1.3 channels, decreases Kv1.3 channel expression and suppresses IL-2 secretion. Therefore, DPO-1 may be a useful treatment strategy for immunologic disorders. PMID:23717641

  6. Comparative assessment of the environmental hazards of and exposure to perfluoroalkyl phosphonic and phosphinic acids (PFPAs and PFPiAs): Current knowledge, gaps, challenges and research needs.

    PubMed

    Wang, Zhanyun; Cousins, Ian T; Berger, Urs; Hungerbühler, Konrad; Scheringer, Martin

    2016-01-01

    Perfluoroalkyl phosphonic and phosphinic acids (PFPAs and PFPiAs) are sub-groups of per- and polyfluoroalkyl substances (PFASs) that have been commercialized since the 1970s, particularly as defoamers in pesticide formulations and wetting agents in consumer products. Recently, C4/C4 PFPiA and its derivatives have been presented as alternatives to long-chain PFASs in certain applications. In this study, we systematically assess the publicly available information on the hazardous properties, occurrence, and exposure routes of PFPAs and PFPiAs, and make comparisons to the corresponding properties of their better-known carboxylic and sulfonic acid analogs (i.e. PFCAs and PFSAs). This comparative assessment indicates that [i] PFPAs likely have high persistence and long-range transport potential; [ii] PFPiAs may transform to PFPAs (and possibly PFCAs) in the environment and biota; [iii] certain PFPAs and PFPiAs can only be slowly eliminated from rainbow trout and rats, similarly to long-chain PFCAs and PFSAs; [iv] PFPAs and PFPiAs have modes-of-action that are both similar to, and different from, those of PFCAs and PFSAs; and [v] the measured levels of PFPAs/PFPiAs in the global environment and biota appear to be low in comparison to PFCAs and PFSAs, suggesting, for the time being, low risks from PFPAs and PFPiAs alone. Although risks from individual PFPAs/PFPiAs are currently low, their ongoing production and use and high persistence will lead to increasing exposure and risks over time. Furthermore, simultaneous exposure to PFPAs, PFPiAs and other PFASs may result in additive effects necessitating cumulative risk assessments. To facilitate effective future research, we highlight possible strategies to overcome sampling and analytical challenges. PMID:26922149

  7. Gas phase ion chemistry and ab initio theoretical study of phosphine. III. Reactions of PH2+ and PH3+ with PH3

    NASA Astrophysics Data System (ADS)

    Antoniotti, Paola; Operti, Lorenza; Rabezzana, Roberto; Tonachini, Glauco; Vaglio, Gian Angelo

    2000-01-01

    The gas phase ion chemistry of phosphine has been investigated by ab initio theoretical calculations and experimental techniques. Following previous studies dealing with 3P+ and PH+ reacting with PH3, the quantum chemical study of these processes has been extended to the ion/molecule reactions starting from PH2+ and PH3 (reaction a) or PH3+ and PH3 (reaction b), as observed by ion trapping. In these experiments, PH2+ reacts to give P2Hn+ (n=1,3) product ions, with loss of H2 through different pathways. These processes take place at quite different rates, their constants being 2.6 and 7.6×10-10 cm3 molecule-1 s-1, respectively. The geometrical structures and energies of transition structures, reaction intermediates, and final products have been determined by ab initio theoretical methods. The initial step of the reaction of PH2+ with PH3 is formation of the H2P-PH3+ adduct. Then, a hydrogen molecule can be directly lost either from tricoordinated or tetracoordinated phosphorus, to give P-PH3+ or HP=PH2+, respectively. The shift of one H atom in HP=PH2+ produces the bridged HP(H)PH+ ion, from which further dissociation of H2 yields PPH+. The initial step of the reaction of PH3+ with PH3 is formation of the H3P-PH3+ adduct. Then inversion of the H atoms in the PH3 group transforms the adduct in an electrostatic complex. This last species is related by a dissociation process to the PH2 and PH4+ products. The heats of formation of the P2Hn+ (n=1-6) ionic species have been computed and compared with the experimental data in the literature.

  8. Potent Suppression of Kv1.3 Potassium Channel and IL-2 Secretion by Diphenyl Phosphine Oxide-1 in Human T Cells

    PubMed Central

    Zhao, Ning; Dong, Qian; Du, Li-Li; Fu, Xiao-Xing; Du, Yi-Mei; Liao, Yu-Hua

    2013-01-01

    Diphenyl phosphine oxide-1 (DPO-1) is a potent Kv1.5 channel inhibitor that has therapeutic potential for the treatment of atrial fibrillation. Many other Kv1.5 channel blockers also potently inhibit the Kv1.3 channel, but whether DPO-1 blocks Kv1.3 channels has not been investigated. The Kv1.3 channel is highly expressed in activated T cells, which is considered a favorable target for immunomodulation. Accordingly, we hypothesized that DPO-1 may exert immunosuppressive and anti-inflammatory effects by inhibiting Kv1.3 channel activity. In this study, DPO-1 blocked Kv1.3 current in a voltage-dependent and concentration-dependent manner, with IC50 values of 2.58 µM in Jurkat cells and 3.11 µM in human peripheral blood T cells. DPO-1 also accelerated the inactivation rate and negatively shifted steady-state inactivation. Moreover, DPO-1 at 3 µM had no apparent effect on the Ca2+ activated potassium channel (KCa) current in both Jurkat cells and human peripheral blood T cells. In Jurkat cells, pre-treatment with DPO-1 for 24 h decreased Kv1.3 current density, and protein expression by 48±6% and 60±9%, at 3 and 10 µM, respectively (both p<0.05). In addition, Ca2+ influx to Ca2+-depleted cells was blunted and IL-2 production was also reduced in activated Jurkat cells. IL-2 secretion was also inhibited by the Kv1.3 inhibitors margatoxin and charybdotoxin. Our results demonstrate for the first time that that DPO-1, at clinically relevant concentrations, blocks Kv1.3 channels, decreases Kv1.3 channel expression and suppresses IL-2 secretion. Therefore, DPO-1 may be a useful treatment strategy for immunologic disorders. PMID:23717641

  9. Photoluminescence properties of four-coordinate gold(I)-phosphine complexes of the types [Au(diphos)2]PF6 and [Au2(tetraphos)2](PF6)2.

    PubMed

    Delfs, Christopher D; Kitto, Heather J; Stranger, Robert; Swiegers, Gerhard F; Wild, S Bruce; Willis, Anthony C; Wilson, Gerard J

    2003-07-14

    Numerous reports describe the photoluminescence of two- and three-coordinate gold(I)-phosphine complexes, but emission in their analogous four-coordinate complexes is almost unknown. This work examines the luminescence of tetrahedral gold(I) complexes of the types [Au(diphos)(2)]PF(6) (diphos = 1,2-bis(diphenylphosphino)ethane, 1) and [Au(2)(tetraphos)(2)](PF(6))(2) (tetraphos = (R,R)-(+/-)/(R,S)-1,1,4,7,10,10-hexaphenyl-1,4,7,10-tetraphosphadecane, (R,R)-(+/-)/(R,S)-2). Although nonemitting in solution, these complexes luminesce with an intense yellow color (lambda(max) 580-620 nm) at 293 K in the solid state or when immobilized as molecular dispersions within solid matrixes. The excited-state lifetimes of the emissions (tau 4.1-9.4 micros) are markedly dependent on the inter- and intramolecular phenyl-phenyl pairing interactions present. At 77 K in an ethanol glass, two transitions are observed: a minor emission at lambda(max) 415-450 nm and a major emission at lambda(max) 520-595 nm. For [Au(1)(2)]PF(6), lifetimes of tau 251.0 +/- 20.5 micros were determined for the former transition and tau 14.9 +/- 4.6 micros for the latter. Density functional theory (DFT) calculations and comparative studies indicate that the former of these emissions involves triplet LMCT pi(Ph) --> Au(d)-P(p) transitions associated with individual P-phenyl groups. The latter emissions, which are the only ones observed at 293 K, are assigned to LMCT pi(Ph-Ph) --> Au(d)-P(p) transitions associated with excited P-phenyl dimers. Other tetrahedral gold(I)-phosphine complexes containing paired P-Ph substituents display similar emissions. The corresponding phosphine ligands, whether free, protonated, or bound to Ag(I), do not exhibit comparable emissions. Far from being rare, luminescence in four-coordinate Au(I)-phosphine complexes appears to be general when stacked P-phenyl groups are present. PMID:12844321

  10. Pd(OAc)2/DABCO as an efficient and phosphine-free catalytic system for the synthesis of single and double Weinreb amides by the aminocarbonylation of aryl iodides.

    PubMed

    Gadge, Sandip T; Bhanage, Bhalchandra M

    2014-08-14

    This work reports a mild, stable and efficient Pd(OAc)2/DABCO catalysed protocol for the synthesis of single and double Weinreb amides. Double Weinreb amides, having 1,4-phenylene- and biphenylene-linkers - important backbones for the synthesis of biologically active symmetrical resorcylate oligomer units - were synthesized by the double carbonylation of aryl diiodides. Notably, the reaction does not require any expensive or air/moisture sensitive phosphine ligands. DABCO was found to be an inexpensive and stable ligand for the Pd(OAc)2 catalysed carbonylation of aryl iodides under an atmospheric pressure of carbon monoxide, and offered excellent yields of the single and double Weinreb amides. PMID:24967832

  11. A photochemical study of the kinetics of the reactions of NH2 with phosphine, ethylene, and acetylene using flash photolysis-laser induced fluorescence. Ph.D. Thesis Catholic Univ. of America; [ammonia in the atmosphere of Jupiter

    NASA Technical Reports Server (NTRS)

    Bosco, S. R.

    1982-01-01

    The photochemistry of the reactions of NH2 was investigated in an attempt to explain the existence of an abundance of ammonia in the Jovian atmosphere. The production of ammonia reservoirs from the coupling of ammonia with other atmospheric constituents was considered. The rate constants for the reactions of NH2 radicals with phosphine, acetylene, and ethylene were measured. Flash photolysis was used for the production of NH2 radicals and laser induced fluorescence was employed for radical detection. It was determined that the rates of the reactions were too slow to be significant as a source of ammonia reservoirs in the Jovian atmosphere.

  12. New and versatile ternary ligand system for technetium radiopharmaceuticals: water soluble phosphines and tricine as coligands in labeling a hydrazinonicotinamide-modified cyclic glycoprotein IIb/IIIa receptor antagonist with 99mTc.

    PubMed

    Edwards, D S; Liu, S; Barrett, J A; Harris, A R; Looby, R J; Ziegler, M C; Heminway, S J; Carroll, T R

    1997-01-01

    A hydrazinonicotinamide-functionalized cyclic platelet glycoprotein IIb/IIIa (GPIIb/IIIa) receptor antagonist [cyclo(D-Val-NMeArg-Gly-Asp-Mamb(5-(6-(6-hydrazinonicotin amido) hexanamide))) (HYNIC-tide)] was labeled with 99mTc using tricine and a water soluble phosphine (TPPTS, trisodium triphenylphosphine-3,3',3"-trisulfonate; TPPDS, disodium triphenylphosphine-3,3'-disulfonate; or TPPMS, sodium triphenylphosphine-3-monosulfonate] as coligands. The synthesis of technetium complexes, [99mTc(HYNICtide)(L)(tricine)] (1, L = TPPTS; 2, L = TPPDS; 3, L = TPPMS), can be performed in one or two steps in high yield and with high specific activity (> or = 20,000 Ci/mmol). For example, the reaction of the HYNICtide, [99mTc]pertechnetate, stannous chloride, and tricine at pH 4-5 and room temperature results in the complex [99mTc(HYNICtide)(tricine)2], which reacts with TPPTS (50 degrees C for 30 min) to give complex 1 in > or = 90% yield as determined by radio-HPLC. Complexes 1-3 are formed as equal mixtures of two isomeric forms and are stable for > or = 6 h in the reaction mixture and in dilute solution. Both isomeric forms of complex 1 were found by a platelet-binding assay to contain the 99mTc-labeled HYNICtide and possess biological activity. The composition of these complexes was determined to be 1:1:1:1 for Tc:HYNICtide:L:tricine through a series of mixed ligand experiments on the tracer (99mTc) level. Surprisingly, this composition is maintained over a wide range of relative ligand ratios. The relative bonding capability of the three phosphine coligands to the Tc was determined by spiking various amounts of TPPDS or TPPMS into TPPTS and falls in the order TPPMS > TPPDS > TPPTS. The lipophilicity of the [99m Tc]HYNICtide complexes can be systematically varied by the choice of the phosphine and aminocarboxylate coligands. Using the combination of tricine and a phosphine ligand, HYNIC-derivatized peptides or other small molecules can be labeled with 99mTc in high specific activity and with high stability for potential use as radiopharmaceuticals. PMID:9095354

  13. Phosphine-stabilised Au{sub 9} clusters interacting with titania and silica surfaces: The first evidence for the density of states signature of the support-immobilised cluster

    SciTech Connect

    Andersson, Gunther G. E-mail: vladimir.golovko@canterbury.ac.nz Al Qahtani, Hassan S.; Golovko, Vladimir B. E-mail: vladimir.golovko@canterbury.ac.nz; Alvino, Jason F.; Bennett, Trystan; Wrede, Oliver; Mejia, Sol M.; Metha, Gregory F. E-mail: vladimir.golovko@canterbury.ac.nz; Adnan, Rohul; Gunby, Nathaniel; Anderson, David P.

    2014-07-07

    Chemically made, atomically precise phosphine-stabilized clusters Au{sub 9}(PPh{sub 3}){sub 8}(NO{sub 3}){sub 3} were deposited on titania and silica from solutions at various concentrations and the samples heated under vacuum to remove the ligands. Metastable induced electron spectroscopy was used to determine the density of states at the surface, and X-ray photoelectron spectroscopy for analysing the composition of the surface. It was found for the Au{sub 9} cluster deposited on titania that the ligands react with the titania substrate. Based on analysis using the singular value decomposition algorithm, the series of MIE spectra can be described as a linear combination of 3 base spectra that are assigned to the spectra of the substrate, the phosphine ligands on the substrate, and the Au clusters anchored to titania after removal of the ligands. On silica, the Au clusters show significant agglomeration after heat treatment and no interaction of the ligands with the substrate can be identified.

  14. Identification and characterization of mechanism of action of P61-E7, a novel phosphine catalysis-based inhibitor of geranylgeranyltransferase-I.

    PubMed

    Chan, Lai N; Fiji, Hannah D G; Watanabe, Masaru; Kwon, Ohyun; Tamanoi, Fuyuhiko

    2011-01-01

    Small molecule inhibitors of protein geranylgeranyltransferase-I (GGTase-I) provide a promising type of anticancer drugs. Here, we first report the identification of a novel tetrahydropyridine scaffold compound, P61-E7, and define effects of this compound on pancreatic cancer cells. P61-E7 was identified from a library of allenoate-derived compounds made through phosphine-catalyzed annulation reactions. P61-E7 inhibits protein geranylgeranylation and blocks membrane association of geranylgeranylated proteins. P61-E7 is effective at inhibiting both cell proliferation and cell cycle progression, and it induces high p21(CIP1/WAF1) level in human cancer cells. P61-E7 also increases p27(Kip1) protein level and inhibits phosphorylation of p27(Kip1) on Thr187. We also report that P61-E7 treatment of Panc-1 cells causes cell rounding, disrupts actin cytoskeleton organization, abolishes focal adhesion assembly and inhibits anchorage independent growth. Because the cellular effects observed pointed to the involvement of RhoA, a geranylgeranylated small GTPase protein shown to influence a number of cellular processes including actin stress fiber organization, cell adhesion and cell proliferation, we have evaluated the significance of the inhibition of RhoA geranylgeranylation on the cellular effects of inhibitors of GGTase-I (GGTIs). Stable expression of farnesylated RhoA mutant (RhoA-F) results in partial resistance to the anti-proliferative effect of P61-E7 and prevents induction of p21(CIP1/WAF1) and p27(Kip1) by P61-E7 in Panc-1 cells. Moreover, stable expression of RhoA-F rescues Panc-1 cells from cell rounding and inhibition of focal adhesion formation caused by P61-E7. Taken together, these findings suggest that P61-E7 is a promising GGTI compound and that RhoA is an important target of P61-E7 in Panc-1 pancreatic cancer cells. PMID:22028818

  15. Synthesis and reactivity of new rhenium(I) complexes containing iminophosphorane-phosphine ligands: application to the catalytic isomerization of propargylic alcohols in ionic liquids.

    PubMed

    Garca-lvarez, Joaqun; Dez, Josefina; Gimeno, Jos; Seifried, Christine M; Vidal, Cristian

    2013-05-01

    [ReBr(CO)5] reacts with the iminophosphorane-phosphine ligands Ph2PCH2P(?NR)Ph2 (R = P(?O)(OEt)2 (1a), P(?O)(OPh)2 (1b), P(?S)(OEt)2 (1c), P(?S)(OPh)2 (1d), 4-C6F4CHO (1e), 4-C6F4CN (1f), 4-C5F4N (1g)) affording the neutral complexes [ReBr(?(2)-P,X-Ph2PCH2P{?NP(?X)(OR)2}Ph2)(CO)3] (X = O, R = Et (2a), Ph (2b); X = S, R = Et (2c), Ph (2d)) and [ReBr{?(2)-P,N-Ph2PCH2P(?NR)Ph2}(CO)3] (R = P(?O)(OEt)2 (3a), P(?O)(OPh)2 (3b), 4-C6F4CHO (3e), 4-C6F4CN (3f), 4-C5F4N (3g)). The reactivity of the cationic complex [Re(?(3)-P,N,S-Ph2PCH2P{?NP(?S)(OPh)2}Ph2)(CO)3][SbF6] (4d) has been explored allowing the synthesis of the cationic [Re(L)(?(2)-P,S-Ph2PCH2P{?NP(?S)(OPh)2}Ph2)(CO)3][SbF6] (L = acetone (5a), CH3C?N (5b), pyridine (5c), PPh3 (5d)) and the neutral [ReY(?(2)-P,S-Ph2PCH2P{?NP(?S)(OPh)2}Ph2)(CO)3] (Y = Cl (6a), I (6b), N3 (6c)) complexes. The catalytic activity of complex 4d in the regioselective isomerization of terminal propargylic alcohols HC?CCR(1)R(2)(OH) into ?,?-unsaturated aldehydes R(1)R(2)C?CHCHO or ketones R(3)R(4)C?CR(1)COMe (if R(2) = CHR(3)R(4)) under neutral conditions in ionic liquids has being studied. Isolation and X-ray characterization of the key intermediate rhenium(I) oxocyclocarbene complex [Re{?C(CH2)3O}(?(2)-P,S-Ph2PCH2P{?NP(?S)(OPh)2}Ph2)(CO)3][SbF6] (5e) seems to indicate that the catalytic reaction proceeds through tautomerization of the terminal alkynols to yield vinilydene-type species. PMID:23594134

  16. A very peculiar family of N-heterocyclic phosphines: unusual structures and the unique reactivity of 1,3,2-diazaphospholenes.

    PubMed

    Gudat, D

    2016-04-14

    This Perspective gives an account of the peculiar electronic and molecular structures of N-heterocyclic phosphines featuring either a single 1,3,2-diazaphospholene (DAP) ring with an exocyclic P-substituent X or two DAP rings linked by a P-P bond (bis-diazaphospholenyls), respectively, and their impact on the chemical properties of these molecules. The bonding situation in simple DAPs is epitomized by strong hyperconjugation between endocyclic π-type electrons and the exocyclic P-X bond. This interaction may induce a perceptible ionic polarization of the P-X bond which can persist even in the limit of a vanishing electronegativity gradient between P and X, and becomes visible in unusual geometric distortions of molecular structures and a unique chemical behaviour. Structural distortions are particularly evident in bond lengthening effects in P-halogen and P-phosphino derivatives R2P-DAP (with R2P ≠ DAP) which span the whole range from covalent molecules to contact ion pairs with a close relation to frustrated Lewis-pairs. The most significant impact on the chemical properties is found for P-phosphino- and P-hydrogen derivatives where reactions at substantially accelerated rates or totally new reaction modes can be observed, and new stoichiometric and first catalytic processes exploiting these features are currently emerging. The recently discovered bis-diazaphospholenyls differ from the simple derivatives as their central bond remains unpolarised as a consequence of the symmetric molecular structure. The occurrence of low-energy P-P bond homolysis that was nonetheless observed in one case is according to the results of thermochemical studies of P-P bond fission reactions attributable to the effects of steric congestion and induces chemical reactivity that can be considered complementary to that of the simple R2P-DAPs. Some concluding remarks will pay attention to a facet of DAP reactivity that has so far been widely neglected but is currently receiving increasing attention, namely well-defined ring-opening processes. PMID:26863391

  17. Self-Assembly of Homochiral Double Helix and Side-by-Side Helix Conformers of Double-Stranded Disilver(I)- and Digold(I)-Tetra(tertiary phosphine) Helicates.

    PubMed

    Airey, Anthea L.; Swiegers, Gerhard F.; Willis, Anthony C.; Wild, S. Bruce

    1997-04-01

    The enantiomers of the (R,R)-(+/-) diastereomer of the chelating C(2)-tetra(tertiary phosphine) (R,R)-(+/-)-1,1,4,7,10,10-hexaphenyl-1,4,7,10-tetraphosphadecane, (R,R)-(+/-)/(R,S)-1, spontaneously self-assemble into homochiral double-stranded disilver(I) and digold(I) helicates of the type [M(2)(tetraphos)(2)]X(2) upon reaction with appropriate silver(I) and gold(I) salts. The corresponding copper(I) complex is mononuclear. Crystal and molecular structures of Delta-(-)-[Cu{(R,R)-1}]PF(6).EtOH, Lambda-(-)-[Ag(2){(R,R)-1}(2)](PF(6))(2), and Lambda-(-)-[Au(2){(R,R)-1}(2)](PF(6))(2).CH(2)Cl(2) are reported. The structure determinations on the silver and gold complexes are the first to be performed on enantiomerically pure dimetal helicates with chiral ligands. The dinuclear silver complex crystallizes with one molecule each of the left-handed (Lambda) D(2)-double helix and C(2)-side-by-side helix conformers of the cation and associated anions in each unit cell, whereas crystals of the analogous gold complex contain only the side-by-side helix and associated anions. The absolute configuration(s) of the metal stereocenter(s) in each complex is S. Conductance measurements in acetonitrile indicated considerable rearrangement of the mononuclear copper complex into the dinuclear helicate complex, whereas the silver and gold complexes conducted as di-univalent salts under similar conditions. Energy minimization calculations of the structures of the disilver complex cation with use of the program SPARTAN 3.0 predicted the structures observed with considerable accuracy, especially the conformations of the chiral central ten-membered ring in the complex and the relationship of the helicity of this ring to the stereoselective formation of the double helix and side-by-side helix structures. The resolution of (R,R)-(+/-)-1 is the first on a tetra(tertiary phosphine). The more-soluble (R,R)-(+/-) form of the ligand was separated in high yield from the less-soluble (R,S) form by selective extraction with tetrahydrofuran, whereupon it was resolved by the method of metal complexation with the readily prepared homochiral complex (+)-di(&mgr;-chloro)bis[(R)-1-[1-(dimethylamino)ethyl]-2-phenyl-C(2),N]dipalladium(II)-1-dichloromethane, (R)-2.CH(2)Cl(2). The enantiomers of the phosphine were obtained by liberation from the diastereomeric complexes (R(C)),(R(P),R(P))- and (R(C)),(S(P),S(P))-3 (X = PF(6)) and brought to optical purity by crystallization from acetone-ethanol, giving colorless needles having mp 88 degrees C and [alpha](21)(D) +20.5 (c 1.0, CH(2)Cl(2)) (S,S enantiomer) and [alpha](21)(D) -20.5 (c 1.0, CH(2)Cl(2)) (R,R enantiomer). The crystal and molecular structures of (R(C)),(R(P),R(P))-3 (X = PF(6)) have been determined. The complete optical purity of each enantiomer of the tetra(tertiary phosphine) was confirmed in each case by the quantitative repreparation of the diastereomeric palladium complex from which it was liberated. PMID:11669747

  18. Undeca­carbonyl-1κ3 C,2κ4 C,3κ4 C-[tris­(3-chloro­phen­yl)phosphine-1κP]-triangulo-triruthenium(0)

    PubMed Central

    Shawkataly, Omar bin; Pankhi, Mohd. Aslam A.; Yeap, Chin Sing; Fun, Hoong-Kun

    2010-01-01

    In the title triangulo-triruthenium compound, [Ru3(C18H12Cl3P)(CO)11], one equatorial carbonyl group has been substituted by the monodentate phosphine ligand, leaving one equatorial and two axial carbonyl substituents on the Ru atom. The remaining two Ru atoms each carry two equatorial and two axial terminal carbonyl ligands. The three benzene rings make dihedral angles of 87.83 (17), 69.91 (17) and 68.26 (17)° with each other. In the crystal structure, mol­ecules are linked into dimers by inter­molecular C—H⋯O hydrogen bonds. The mol­ecular structure is stabilized by an intra­molecular C—H⋯O hydrogen bond. PMID:21579060

  19. Undeca-carbonyl-1κC,2κC,3κC-[tris-(3-chloro-phen-yl)phosphine-1κP]-triangulo-triruthenium(0).

    PubMed

    Shawkataly, Omar Bin; Pankhi, Mohd Aslam A; Yeap, Chin Sing; Fun, Hoong-Kun

    2010-01-01

    In the title triangulo-triruthenium compound, [Ru(3)(C(18)H(12)Cl(3)P)(CO)(11)], one equatorial carbonyl group has been substituted by the monodentate phosphine ligand, leaving one equatorial and two axial carbonyl substituents on the Ru atom. The remaining two Ru atoms each carry two equatorial and two axial terminal carbonyl ligands. The three benzene rings make dihedral angles of 87.83 (17), 69.91 (17) and 68.26 (17)° with each other. In the crystal structure, mol-ecules are linked into dimers by inter-molecular C-H⋯O hydrogen bonds. The mol-ecular structure is stabilized by an intra-molecular C-H⋯O hydrogen bond. PMID:21579060

  20. Regiodivergent Enantioselective γ-Additions of Oxazolones to 2,3-Butadienoates Catalyzed by Phosphines: Synthesis of α,α-Disubstituted α-Amino Acids and N,O-Acetal Derivatives.

    PubMed

    Wang, Tianli; Yu, Zhaoyuan; Hoon, Ding Long; Phee, Claire Yan; Lan, Yu; Lu, Yixin

    2016-01-13

    Phosphine-catalyzed regiodivergent enantioselective C-2- and C-4-selective γ-additions of oxazolones to 2,3-butadienoates have been developed. The C-4-selective γ-addition of oxazolones occurred in a highly enantioselective manner when 2-aryl-4-alkyloxazol-5-(4H)-ones were employed as pronucleophiles. With the employment of 2-alkyl-4-aryloxazol-5-(4H)-ones as the donor, C-2-selective γ-addition of oxazolones took place in a highly enantioselective manner. The C-4-selective adducts provided rapid access to optically enriched α,α-disubstituted α-amino acid derivatives, and the C-2-selective products led to facile synthesis of chiral N,O-acetals and γ-lactols. Theoretical studies via DFT calculations suggested that the origin of the observed regioselectivity was due to the distortion energy that resulted from the interaction between the nucleophilic oxazolide and the electrophilic phosphonium intermediate. PMID:26629975

  1. Regioselective complexation of unprotected carbohydrates by platinum(II). Synthesis, structure, complexation equilibria, and hydrogen-bonding in carbonate-derived bis(phosphine)platinum(II) diolate and alditolate complexes

    SciTech Connect

    Andrews, M.A.; Voss, E.J.; Gould, G.L.; Klooster, W.T.; Koetzle, T.F. )

    1994-06-29

    Treatment of bis(phosphine)platinum(II) carbonate complexes (LL)Pt(CO[sub 3]) (e.g., LL = 1,3-bis(diphenylphosphino)propane) with vicinal diols (i.e., HOCR[sup 1]R[sup 2]CR[sup 3]R[sup 4]OH) gives equilibrium conversion to the corresponding diolate complexes (LL)Pt(OCR[sup 1]R[sup 2]CR[sup 3]R[sup 4]O), which are readily isolated in good yield. From competition experiments, relative diol complexation constants were determined as a function of both the diol and the phosphine substituents and found to span a range of over 10[sup 4]. Corresponding triolate and alditolate complexes were similarly prepared, for which very distinct equilibrium isomeric regioselectivities are observed, favoring complexation of [gamma],[delta]-threo diols. An X-ray structure of (dppp)Pt(D-mannitolate) shows that the mannitol is bonded to the platinum as its dianion via the oxygens on C3 and C4 to form a 2,5-dioxaplatinacyclopentane chelate ring and that three different strong intramolecular hydrogen-bonding interactions are present between the hydroxyl hydrogens and the metallacycle oxygens (O-O) (av) = 2.65(2) [angstrom], forming five-, six-, and seven-membered rings. Crystal data for PtP[sub 2]O[sub 6]C[sub 33]H[sub 38]-CH[sub 2]Cl[sub 2]: P2[sub 1]2[sub 1]2[sub 1], Z = 4, T = 20 [degree]C, a = 11.225(2) [angstrom], b = 15.875(3) [angstrom], c = 19.964(4) [angstrom], R(F[sub 0]) = 0.058, R[sub w](F[sub o]) = 0.062. 78 refs., 4 figs., 6 tabs.

  2. Quantum dynamics on a three-sheeted six-dimensional ab initio potential-energy surface of the phosphine cation: Simulation of the photoelectron spectrum and the ultrafast radiationless decay dynamics

    NASA Astrophysics Data System (ADS)

    Bhattacharyya, Swarnendu; Dai, Zuyang; Domcke, Wolfgang

    2015-11-01

    A diabatic three-sheeted six-dimensional potential-energy surface has been constructed for the ground state and the lowest excited state of the PH3+ cation. Coupling terms of Jahn-Teller and pseudo-Jahn-Teller origin up to eighth order had to be included to describe the pronounced anharmonicity of the surface due to multiple conical intersections. The parameters of the diabatic Hamiltonian have been optimized by fitting the eigenvalues of the potential-energy matrix to ab initio data calculated at the CASSCF/MRCI level employing the correlation-consistent triple-ζ basis. The theoretical photoelectron spectrum of phosphine and the non-adiabatic nuclear dynamics of the phosphine cation have been computed by propagating nuclear wave packets with the multiconfiguration time-dependent Hartree method. The theoretical photoelectron bands obtained by Fourier transformation of the autocorrelation function agree well with the experimental results. It is shown that the ultrafast non-radiative decay dynamics of the first excited state of PH3+ is dominated by the exceptionally strong Jahn-Teller coupling of the asymmetric bending vibrational mode together with a hyperline of conical intersections with the electronic ground state induced by the umbrella mode. Time-dependent population probabilities have been computed for the three adiabatic electronic states. The non-adiabatic Jahn-Teller dynamics within the excited state takes place within ≈5 fs. Almost 80% of the excited-state population decay to the ground state within about 10 fs. The wave packets become highly complex and delocalized after 20 fs and no further significant transfer of electronic population seems to occur up to 100 fs propagation time.

  3. Tertiary phosphine complexes of the f-block metals. Preparation of pentamethylcyclopentadienyl-tertiary phosphine complexes of ytterbium(II), ytterbium(III), and europium(II). Crystal structure of Yb(Me/sub 5/C/sub 5/)/sub 2/Cl(Me/sub 2/PCH/sub 2/PMe/sub 2/)

    SciTech Connect

    Tilley, T.D.; Andersen, R.A.; Zalkin, A.

    1983-03-16

    The diphosphine, Me/sub 2/PCH/sub 2/CH/sub 2/PMe/sub 2/, reacts with M(Me/sub 5/C/sub 5/)/sub 2/(OEt/sub 2/) to give insoluble M(Me/sub 5/C/sub 5/)/sub 2/(Me/sub 2/PCH/sub 2/CH/sub 2/PMe/sub 2/), where M is Eu or Yb. In contrast, Me/sub 2/PCH/sub 2/PMe/sub 2/ gives the hydrocarbon-soluble complexes M(Me/sub 5/C/sub 5/)/sub 2/(Me/sub 2/PCH/sub 2/PMe/sub 2/), where M is Eu or Yb. The ytterbium complex reacts with YbCl/sub 3/ in toluene to give Yb(Me/sub 5/C/sub 5/)/sub 2/Cl(Me/sub 2/PCH/sub 2/PMe/sub 2/), and the crystal structure shows that the phosphine is acting as a monodentate ligand. Yb(Me/sub 5/C/sub 5/)/sub 2/Cl(Me/sub 2/PCH/sub 2/PMe/sub 2/) crystallizes in the monoclinic space group P2/sub 1//c with a = 16.358 (6) A, b = 8.595 (4) A, c - 20.712 (7) A, ..beta.. = 104.75 (4)/sup 0/, V = 2816 A/sup 3/, and d(calcd) = 1.45 g cm/sup -3/ for Z = 4 and mol wt = 615.15. Diffraction data were collected with a CAD-4 automated diffractometer, and the structure was refined to R = 0.054 for 3309 reflections with 4/sup 0/ < 2theta < 45/sup 0/ (Mo K..cap alpha.. radiation). The Yb is coordinated to the two Me/sub 5/C/sub 5/ groups, to the chlorine atom, and to one phosphorus atom of the bis(dimethylphosphino)methane ligand. The Yb-P and Yb-Cl distances are 2.94 and 2.53 A, respectively. The centroids of the C/sub 5/Me/sub 5/ ligands and the Cl and P atoms are in an approximate tetrahedral arrangement about the Yb atom.

  4. [μ-Bis(diphenyl-arsino)methane-1:2κAs:As']nona-carbonyl-1κC,2κC,3κC-[(penta-fluoro-phen-yl)diphenyl-phosphine-3κP]-triangulo-triruthenium(0) chloro-form monosolvate.

    PubMed

    Shawkataly, Omar Bin; Khan, Imthyaz Ahmed; Yeap, Chin Sing; Fun, Hoong-Kun

    2010-01-01

    The asymmetric unit of the title triangulo-triruthenium compound, [Ru(3)(C(25)H(22)As(2))(C(18)H(10)F(5)P)(CO)(9)]·CHCl(3), contains one mol-ecule of the triangulo-triruthenium complex and one mol-ecule of the disordered chloro-form solvent. The bis-(diphenyl-arsino)methane ligand bridges an Ru-Ru bond and the monodentate phosphine ligand bonds to the third Ru atom. Both the arsine and phosphine ligands are equatorial with respect to the Ru(3) triangle. In addition, each Ru atom carries one equatorial and two axial terminal carbonyl ligands. The phosphine-substituted benzene rings make dihedral angles of 68.43 (15), 65.14 (14) and 89.75 (14)° with each other. The dihedral angles between the two benzene rings are 80.70 (15) and 84.53 (16)° for the two diphenyl-arsino groups. In the crystal packing, the mol-ecules are linked into a plane parallel to bc by inter-molecular C-H⋯O and C-H⋯F hydrogen bonds. Weak inter-molecular C-H⋯π inter-actions further stabilize the crystal structure. PMID:21579648

  5. [μ-Bis(diphenyl­arsino)methane-1:2κ2 As:As′]nona­carbonyl-1κ3 C,2κ3 C,3κ3 C-[(penta­fluoro­phen­yl)diphenyl­phosphine-3κP]-triangulo-triruthenium(0) chloro­form monosolvate

    PubMed Central

    Shawkataly, Omar bin; Khan, Imthyaz Ahmed; Yeap, Chin Sing; Fun, Hoong-Kun

    2010-01-01

    The asymmetric unit of the title triangulo-triruthenium compound, [Ru3(C25H22As2)(C18H10F5P)(CO)9]·CHCl3, contains one mol­ecule of the triangulo-triruthenium complex and one mol­ecule of the disordered chloro­form solvent. The bis­(diphenyl­arsino)methane ligand bridges an Ru—Ru bond and the monodentate phosphine ligand bonds to the third Ru atom. Both the arsine and phosphine ligands are equatorial with respect to the Ru3 triangle. In addition, each Ru atom carries one equatorial and two axial terminal carbonyl ligands. The phosphine-substituted benzene rings make dihedral angles of 68.43 (15), 65.14 (14) and 89.75 (14)° with each other. The dihedral angles between the two benzene rings are 80.70 (15) and 84.53 (16)° for the two diphenyl­arsino groups. In the crystal packing, the mol­ecules are linked into a plane parallel to bc by inter­molecular C—H⋯O and C—H⋯F hydrogen bonds. Weak inter­molecular C—H⋯π inter­actions further stabilize the crystal structure. PMID:21579648

  6. [μ-Bis(diphenyl-arsino)methane-1:2κAs:As']nona-carbonyl-1κC,2κC,3κC-[tris-(4-fluoro-phen-yl)phosphine-3κP]-triangulo-triruthenium(0).

    PubMed

    Shawkataly, Omar Bin; Khan, Imthyaz Ahmed; Yeap, Chin Sing; Fun, Hoong-Kun

    2009-01-01

    In the title triangulo-triruthenium compound, [Ru(3)(C(25)H(22)(As(2))(C(18)H(12)F(3)P)(CO)(9)], the bis-(diphenyl-arsino)methane ligand bridges an Ru-Ru bond and the monodentate phosphine ligand bonds to the third Ru atom. Both the phosphine and arsine ligands are equatorial with respect to the Ru(3) triangle. Additionally, each Ru atom carries one equatorial and two axial terminal carbonyl ligands. The three phosphine-substituted rings make dihedral angles of 87.76 (13), 57.43 (13) and 73.81 (12)° with each other. The dihedral angles between the pairs of rings are 69.78 (14) and 83.38 (16)° for the two diphenyl-arsino groups. In the crystal packing, mol-ecules are linked by inter-molecular C-H⋯F and C-H⋯O hydrogen bonds, forming two-dimensional planes parallel to the ab plane. These planes are also linked by inter-molecular C-H⋯O hydrogen bonds into a three-dimensional framework. Inter-molecular C-H⋯π inter-actions further stabilize the crystal structure. PMID:21578643

  7. [μ-Bis(diphenyl-arsino)methane-1:2κAs:As']nona-carbonyl-1κC,2κC,3κC-[tris-(4-methyl-phen-yl)-phosphine-3κP]-triangulo-triruthenium(0).

    PubMed

    Shawkataly, Omar Bin; Khan, Imthyaz Ahmed; Yeap, Chin Sing; Fun, Hoong-Kun

    2009-01-01

    In the title triangulo-triruthenium compound, [Ru(3)(C(25)H(22)As(2))(C(21)H(21)P)(CO)(9)], the bis-(diphenyl-arsino)methane ligand bridges a Ru-Ru bond and the monodentate phosphine ligand bonds to the third Ru atom. Both the phosphine and arsine ligands are equatorial with respect to the Ru(3) triangle. Additionally, each Ru atom carries one equatorial and two axial terminal carbonyl ligands. The three phenyl rings of the phosphine make dihedral angles of 86.89 (19), 82.1 (2) and 63.0 (2)° with each other. The dihedral angles between the two phenyl rings are 73.8 (2) and 82.2 (3)° for the two diphenyl-arsino groups. An intra-molecular C-H⋯O hydrogen bond stabilizes the mol-ecular structure. In the crystal packing, mol-ecules are linked into chains down the b axis via inter-molecular C-H⋯O hydrogen bonds. PMID:21579935

  8. [μ-Bis(diphenyl­arsino)methane-1:2κ2 As:As′]nona­carbonyl-1κ3 C,2κ3 C,3κ3 C-[tris­(4-fluoro­phen­yl)phosphine-3κP]-triangulo-triruthenium(0)

    PubMed Central

    Shawkataly, Omar bin; Khan, Imthyaz Ahmed; Yeap, Chin Sing; Fun, Hoong-Kun

    2009-01-01

    In the title triangulo-triruthenium compound, [Ru3(C25H22(As2)(C18H12F3P)(CO)9], the bis­(diphenyl­arsino)methane ligand bridges an Ru—Ru bond and the monodentate phosphine ligand bonds to the third Ru atom. Both the phosphine and arsine ligands are equatorial with respect to the Ru3 triangle. Additionally, each Ru atom carries one equatorial and two axial terminal carbonyl ligands. The three phosphine-substituted rings make dihedral angles of 87.76 (13), 57.43 (13) and 73.81 (12)° with each other. The dihedral angles between the pairs of rings are 69.78 (14) and 83.38 (16)° for the two diphenyl­arsino groups. In the crystal packing, mol­ecules are linked by inter­molecular C—H⋯F and C—H⋯O hydrogen bonds, forming two-dimensional planes parallel to the ab plane. These planes are also linked by inter­molecular C—H⋯O hydrogen bonds into a three-dimensional framework. Inter­molecular C—H⋯π inter­actions further stabilize the crystal structure. PMID:21578643

  9. [μ-Bis(diphenyl­arsino)methane-1:2κ2 As:As′]nona­carbonyl-1κ3 C,2κ3 C,3κ3 C-[tris­(4-methyl­phen­yl)­phosphine-3κP]-triangulo-triruthenium(0)

    PubMed Central

    Shawkataly, Omar bin; Khan, Imthyaz Ahmed; Yeap, Chin Sing; Fun, Hoong-Kun

    2010-01-01

    In the title triangulo-triruthenium compound, [Ru3(C25H22As2)(C21H21P)(CO)9], the bis­(diphenyl­arsino)methane ligand bridges a Ru—Ru bond and the monodentate phosphine ligand bonds to the third Ru atom. Both the phosphine and arsine ligands are equatorial with respect to the Ru3 triangle. Additionally, each Ru atom carries one equatorial and two axial terminal carbonyl ligands. The three phenyl rings of the phosphine make dihedral angles of 86.89 (19), 82.1 (2) and 63.0 (2)° with each other. The dihedral angles between the two phenyl rings are 73.8 (2) and 82.2 (3)° for the two diphenyl­arsino groups. An intra­molecular C—H⋯O hydrogen bond stabilizes the mol­ecular structure. In the crystal packing, mol­ecules are linked into chains down the b axis via inter­molecular C—H⋯O hydrogen bonds. PMID:21579935

  10. Unraveling the formation of HCPH(X2A') molecules in extraterrestrial environments: crossed molecular beam study of the reaction of carbon atoms, C(3Pj), with phosphine, PH3(X1A1).

    PubMed

    Guo, Y; Gu, X; Zhang, F; Sun, B J; Tsai, M F; Chang, A H H; Kaiser, R I

    2007-05-01

    The reaction between ground state carbon atoms, C(3P(j)), and phosphine, PH3(X(1)A1), was investigated at two collision energies of 21.1 and 42.5 kJ mol(-1) using the crossed molecular beam technique. The chemical dynamics extracted from the time-of-flight spectra and laboratory angular distributions combined with ab initio calculations propose that the reaction proceeds on the triplet surface via an addition of atomic carbon to the phosphorus atom. This leads to a triplet CPH3 complex. A successive hydrogen shift forms an HCPH2 intermediate. The latter was found to decompose through atomic hydrogen emission leading to the cis/trans-HCPH(X(2)A') reaction products. The identification of cis/trans-HCPH(X(2)A') molecules under single collision conditions presents a potential pathway to form the very first carbon-phosphorus bond in extraterrestrial environments like molecular clouds and circumstellar envelopes, and even in the postplume chemistry of the collision of comet Shoemaker-Levy 9 with Jupiter. PMID:17428038

  11. Configurationally homogeneous diastereomers of a linear hexa(tertiary phosphine): Enantioselective self-assembly of a double-stranded parallel helicate of the type (P)-[Cu3(hexaphos)2](PF6)3

    PubMed Central

    Bowyer, Paul K.; Cook, Vernon C.; Gharib-Naseri, Nahid; Gugger, Paul A.; Rae, A. David; Swiegers, Gerhard F.; Willis, Anthony C.; Zank, Johann; Wild, S. Bruce

    2002-01-01

    Three configurationally homogeneous diastereomers of the linear hexa(tertiary phosphine) Ph2PCH2CH2P(Ph)CH2CH2P(Ph)CH2CH2P(Ph)CH2CH2P(Ph)CH2CH2PPh2 (hexaphos) have been isolated in enantiomerically pure form, namely (R,S,S,R)-, (R,S,S,S)-, and (S,S,S,S)-hexaphos. The strongly helicating (R,S,S,R)-(−) form of the ligand combines with copper(I) ions to generate by stereoselective self-assembly the P enantiomer of a parallel helicate of the type [Cu3(hexaphos)2](PF6)3, which has been characterized by x-ray crystallography. Theoretical modeling of the cation indicates that it is the relationship between the helicities of the two 10-membered rings containing the three copper ions, each of which has the twist-boat–chair–boat conformation, and the configurations of the three chiral, tetrahedral copper stereocenters of P configuration that determines the stereochemistry of the parallel and double α-helix conformers of the double-stranded trinuclear metal helicate. PMID:11929976

  12. Efficient general procedure to access a diversity of gold(0) particles and gold(I) phosphine complexes from a simple HAuCl4 source. Localization of homogeneous/heterogeneous system's interface and field-emission scanning electron microscopy study.

    PubMed

    Zalesskiy, Sergey S; Sedykh, Alexander E; Kashin, Alexey S; Ananikov, Valentine P

    2013-03-01

    Soluble gold precatalysts, aimed for homogeneous catalysis, under certain conditions may form nanoparticles, which dramatically change the mechanism and initiate different chemistry. The present study addresses the question of designing gold catalysts, taking into account possible interconversions and contamination at the homogeneous/heterogeneous system's interface. It was revealed that accurate localization of boundary experimental conditions for formation of molecular gold complexes in solution versus nucleation and growth of gold particles opens new opportunities for well-known gold chemistry. Within the developed concept, a series of practical procedures was created for efficient synthesis of soluble gold complexes with various phosphine ligands (R3P)AuCl (90-99% yield) and for preparation of different types of gold materials. The effect of the ligand on the particles growth in solution has been observed and characterized with high-resolution field-emission scanning electron microscopy (FE-SEM) study. Two unique types of nanostructured gold materials were prepared: hierarchical agglomerates and gold mirror composed of ultrafine smoothly shaped particles. PMID:23276227

  13. Decacarbonyl-1κC,2κC,3κC-bis-[tris-(3-chloro-phen-yl)phosphine]-1κP,2κP-triangulo-triruthenium(0) monohydrate.

    PubMed

    Shawkataly, Omar Bin; Pankhi, Mohd Aslam A; Yeap, Chin Sing; Fun, Hoong-Kun

    2010-01-01

    The asymmetric unit of the title triangulo-triruthenium compound, [Ru(3)(C(18)H(12)Cl(3)P)(2)(CO)(10)]·H(2)O, consists of one triangulo-triruthenium complex and one disordered water solvent molecule. Two of the 3-chloro-phenyl rings are disordered over two positions with refined site occupancies of 0.671 (3)/0.329 (3) and 0.628 (3)/0.372 (3). The water mol-ecule is disordered over two positions with refined site occupancies of 0.523 (7) and 0.477 (7). Two equatorial carbonyl groups have been substituted by the two monodentate phosphine ligands, leaving one equatorial and two axial carbonyl substituents on the two Ru atoms. The remaining Ru atom carries two equatorial and two axial terminal carbonyl ligands. In the crystal structure, mol-ecules are linked into columns along the a axis by inter-molecular C-H⋯Cl and C-H⋯O hydrogen bonds. The mol-ecular structure is stabilized by weak intra-molecular C-H⋯O hydrogen bonds. PMID:21579061

  14. Decacarbonyl-1κ3 C,2κ3 C,3κ4 C-bis­[tris­(3-chloro­phen­yl)phosphine]-1κP,2κP-triangulo-triruthenium(0) monohydrate

    PubMed Central

    Shawkataly, Omar bin; Pankhi, Mohd. Aslam A.; Yeap, Chin Sing; Fun, Hoong-Kun

    2010-01-01

    The asymmetric unit of the title triangulo-triruthenium compound, [Ru3(C18H12Cl3P)2(CO)10]·H2O, consists of one triangulo-triruthenium complex and one disordered water solvent molecule. Two of the 3-chloro­phenyl rings are disordered over two positions with refined site occupancies of 0.671 (3)/0.329 (3) and 0.628 (3)/0.372 (3). The water mol­ecule is disordered over two positions with refined site occupancies of 0.523 (7) and 0.477 (7). Two equatorial carbonyl groups have been substituted by the two monodentate phosphine ligands, leaving one equatorial and two axial carbonyl substituents on the two Ru atoms. The remaining Ru atom carries two equatorial and two axial terminal carbonyl ligands. In the crystal structure, mol­ecules are linked into columns along the a axis by inter­molecular C—H⋯Cl and C—H⋯O hydrogen bonds. The mol­ecular structure is stabilized by weak intra­molecular C—H⋯O hydrogen bonds. PMID:21579061

  15. The N domain of human angiotensin-I-converting enzyme: the role of N-glycosylation and the crystal structure in complex with an N domain-specific phosphinic inhibitor, RXP407.

    PubMed

    Anthony, Colin S; Corradi, Hazel R; Schwager, Sylva L U; Redelinghuys, Pierre; Georgiadis, Dimitris; Dive, Vincent; Acharya, K Ravi; Sturrock, Edward D

    2010-11-12

    Angiotensin-I-converting enzyme (ACE) plays a critical role in the regulation of blood pressure through its central role in the renin-angiotensin and kallikrein-kinin systems. ACE contains two domains, the N and C domains, both of which are heavily glycosylated. Structural studies of ACE have been fraught with severe difficulties because of surface glycosylation of the protein. In order to investigate the role of glycosylation in the N domain and to create suitable forms for crystallization, we have investigated the importance of the 10 potential N-linked glycan sites using enzymatic deglycosylation, limited proteolysis, and mass spectrometry. A number of glycosylation mutants were generated via site-directed mutagenesis, expressed in CHO cells, and analyzed for enzymatic activity and thermal stability. At least eight of 10 of the potential glycan sites are glycosylated; three C-terminal sites were sufficient for expression of active N domain, whereas two N-terminal sites are important for its thermal stability. The minimally glycosylated Ndom389 construct was highly suitable for crystallization studies. The structure in the presence of an N domain-selective phosphinic inhibitor RXP407 was determined to 2.0 Å resolution. The Ndom389 structure revealed a hinge region that may contribute to the breathing motion proposed for substrate binding. PMID:20826823

  16. Bis{[μ-bis­(diphenyl­arsino)methane-1:2κ2 As:As′]nona­carbonyl-1κ3 C,2κ3 C,3κ3 C-[tris­(4-chloro­phen­yl)phosphine-3κP]-triangulo-triruthenium(0)} chloro­form monosolvate

    PubMed Central

    Shawkataly, Omar bin; Khan, Imthyaz Ahmed; Yeap, Chin Sing; Fun, Hoong-Kun

    2010-01-01

    The asymmetric unit of the title triangulo-triruthenium compound, 2[Ru3(C25H22As2)(C18H12Cl3P)(CO)9]·CHCl3, consists of two mol­ecules (A and B) of the triangulo-triruthenium complex and one mol­ecule of chloro­form solvent. The bis­(diphenyl­arsino)methane ligand bridges an Ru—Ru bond and the monodentate phosphine ligand bonds to the third Ru atom. Both the phosphine and arsine ligands are equatorial with respect to the Ru3 triangle. In addition, each Ru atom carries one equatorial and two axial terminal carbonyl ligands. The three phosphine-substituted benzene rings make dihedral angles of 73.5 (3), 57.2 (3) and 75.7 (3)° with each other in mol­ecule A, while these angles are 60.7 (3), 86.8 (3) and 54.9 (3)° in mol­ecule B. The dihedral angles between the two benzene rings are 87.3 (3) and 89.6 (3)° for the two diphenyl­arsino groups in mol­ecule A and 85.6 (3) and 87.7 (3)° in mol­ecule B. In the crystal packing, the mol­ecules are linked into a three-dimensional framework via inter­molecular C—H⋯O and C—H⋯Cl hydrogen bonds. Weak inter­molecular C—H⋯π inter­actions furture stabilize the crystal structure. The crystal studied was an inversion twin, the refined ratio of twin components being 0.480 (7):0.520 (7). PMID:21579981

  17. [μ-Bis(diphenyl­arsino)methane-1:2κ2 As:As′]nona­carbonyl-1κ3 C,2κ3 C,3κ3 C-tricyclo­hexyl­phosphine-3κP-triangulo-triruthenium(0)

    PubMed Central

    Shawkataly, Omar bin; Khan, Imthyaz Ahmed; Yeap, Chin Sing; Fun, Hoong-Kun

    2009-01-01

    In the title triangulo-triruthenium compound, [Ru3(C25H22As2)(C18H33P)(CO)9], the bis­(diphenyl­arsino)methane ligand bridges an Ru—Ru bond and the monodentate phosphine ligand bonds to the third Ru atom. Both the phosphine and arsine ligands are equatorial with respect to the Ru3 triangle. In addition, each Ru atom carries one equatorial and two axial terminal carbonyl ligands. All three cyclo­hexane rings are disordered over two positions with site occupancies of 0.628 (6) and 0.372 (6). The mean planes of these three phosphine-substituted cyclo­hexane rings make dihedral angles of 53.0 (8), 68.3 (6) and 89.9 (7)° (major components), and 46.7 (14), 41.3 (11) and 75.8 (10)° (minor components) with each other. The dihedral angles between the two phenyl rings are 85.0 (2) and 88.1 (2)° for the two diphenyl­arsino groups. Two cyclo­hexane rings adopt a chair conformation whereas the other adopts a slightly twisted chair conformation for the major components; these conformations are similiar for the minor components. Intra­molecular C—H⋯O hydrogen bonds stabilize the mol­ecular structure. In the crystal packing, the mol­ecules are linked together into chains via inter­molecular C—H⋯O hydrogen bonds down the a axis. Weak inter­molecular C—H⋯π inter­actions further stabilize the crystal structure. PMID:21578646

  18. Bis{[μ-bis-(diphenyl-arsino)methane-1:2κAs:As']nona-carbonyl-1κC,2κC,3κC-[tris-(4-chloro-phen-yl)phosphine-3κP]-triangulo-triruthenium(0)} chloro-form monosolvate.

    PubMed

    Shawkataly, Omar Bin; Khan, Imthyaz Ahmed; Yeap, Chin Sing; Fun, Hoong-Kun

    2009-01-01

    The asymmetric unit of the title triangulo-triruthenium compound, 2[Ru(3)(C(25)H(22)As(2))(C(18)H(12)Cl(3)P)(CO)(9)]·CHCl(3), consists of two mol-ecules (A and B) of the triangulo-triruthenium complex and one mol-ecule of chloro-form solvent. The bis-(diphenyl-arsino)methane ligand bridges an Ru-Ru bond and the monodentate phosphine ligand bonds to the third Ru atom. Both the phosphine and arsine ligands are equatorial with respect to the Ru(3) triangle. In addition, each Ru atom carries one equatorial and two axial terminal carbonyl ligands. The three phosphine-substituted benzene rings make dihedral angles of 73.5 (3), 57.2 (3) and 75.7 (3)° with each other in mol-ecule A, while these angles are 60.7 (3), 86.8 (3) and 54.9 (3)° in mol-ecule B. The dihedral angles between the two benzene rings are 87.3 (3) and 89.6 (3)° for the two diphenyl-arsino groups in mol-ecule A and 85.6 (3) and 87.7 (3)° in mol-ecule B. In the crystal packing, the mol-ecules are linked into a three-dimensional framework via inter-molecular C-H⋯O and C-H⋯Cl hydrogen bonds. Weak inter-molecular C-H⋯π inter-actions furture stabilize the crystal structure. The crystal studied was an inversion twin, the refined ratio of twin components being 0.480 (7):0.520 (7). PMID:21579981

  19. (Benzyl­diphenyl­phosphine-3κP)[μ-bis(diphenyl­arsino)methane-1:2κ2 As:As′]nona­carbonyl-1κ3 C,2κ3 C,3κ3 C-triangulo-triruthenium(0)

    PubMed Central

    Shawkataly, Omar bin; Khan, Imthyaz Ahmed; Yeap, Chin Sing; Fun, Hoong-Kun

    2010-01-01

    The asymmetric unit of the title triangulo-triruthenium compound, [Ru3(C25H22As2)(C19H17P)(CO)9], consists of two crystallographically independent mol­ecules of the triangulo-triruthenium complex, A and B. The bis­(diphenyl­arsino)methane ligand bridges an Ru—Ru bond and the monodentate phosphine ligand bonds to the third Ru atom. Both the phosphine and arsine ligands are equatorial with respect to the Ru3 triangle. In addition, each Ru atom carries one equatorial and two axial terminal carbonyl ligands. With regard to the three phosphine-substituted rings, the benzyl ring makes dihedral angles of 41.0 (3) and 43.9 (3)° with the other two benzene rings in mol­ecule A; these angles are 49.8 (3) and 56.8 (3)° in mol­ecule B. The dihedral angles between the two benzene rings are 76.1 (3) and 88.2 (3)° for the two diphenyl­arsino groups in mol­ecule A and 71.3 (3) and 78.1 (3)° in mol­ecule B. In the crystal packing, mol­ecules are linked into chains via inter­molecular C—H⋯O hydrogen bonds. Weak inter­molecular C—H⋯π inter­actions further stabilize the crystal structure. PMID:21579968

  20. Reactivity of a Fe(III)-Bound Methoxide Supported with a Tris(thiolato)phosphine Ligand: Activation of C-Cl Bond in CH2Cl2 by Nucleophilic Attack of a Fe(III)-OCH3 Moiety.

    PubMed

    Chang, Kai-Chun; Huang, Ching-Ju; Chang, Ya-Ho; Wu, Zong-Han; Kuo, Ting-Shen; Hsu, Hua-Fen

    2016-01-19

    Two mononuclear nonheme Fe(III) complexes, [PPh4][Fe(III)(PS3″)(OCH3)] (1) and [PPh4][Fe(III)(PS3″)(Cl)] (2), supported by a tris(benzenethiolato)phosphine derivative PS3″ (PS3″ = P(C6H3-3-Me3Si-2-S)3(3-)) have been synthesized and characterized. The structures resolved from X-ray crystallography show that Fe(III) centers in both complexes adopt distorted trigonal-bipyramidal geometry with a methoxide or a chloride binding in the axial position. The magnetic data for both are consistent with intermediate-spin Fe(III) centers with a C3 symmetry (S = 3/2 ground state). The bound methoxide in 1 is labile and can be replaced by a CH3CN molecule. The forming Fe(III)-CH3CN species can be further reduced by cobaltcene quantitatively to a stable Fe(II)-CH3CN complex, [Fe(PS3″)(CH3CN)](-). One-electron oxidation of 2 by ferrocenium gave a Fe(IV) analogue, [Fe(IV)(PS3″)(Cl)]. Importantly, the Fe(III)-OCH3 moiety in complex 1 acts as a strong nucleophile that activates the C-Cl bond in CH2Cl2, leading to the formation of complex 2 quantitatively. Complex 1 also reacts with other electrophiles, benzyl chloride and benzyl bromide, to generate Fe(III)-X species (X = Cl or Br). The reactions were investigated and monitored by UV-vis-NIR, NMR, and ESI-MS spectroscopies. PMID:26699874

  1. Bioinspired Hydrogenase Models: The Mixed-Valence Triiron Complex [Fe3(CO)7(μ-edt)2] and Phosphine Derivatives [Fe3(CO)7-x (PPh3) x (μ-edt)2] (x = 1, 2) and [Fe3(CO)5(κ(2)-diphosphine)(μ-edt)2] as Proton Reduction Catalysts.

    PubMed

    Rahaman, Ahibur; Ghosh, Shishir; Unwin, David G; Basak-Modi, Sucharita; Holt, Katherine B; Kabir, Shariff E; Nordlander, Ebbe; Richmond, Michael G; Hogarth, Graeme

    2014-03-24

    The mixed-valence triiron complexes [Fe3(CO)7-x (PPh3) x (μ-edt)2] (x = 0-2; edt = SCH2CH2S) and [Fe3(CO)5(κ(2)-diphosphine)(μ-edt)2] (diphosphine = dppv, dppe, dppb, dppn) have been prepared and structurally characterized. All adopt an anti arrangement of the dithiolate bridges, and PPh3 substitution occurs at the apical positions of the outer iron atoms, while the diphosphine complexes exist only in the dibasal form in both the solid state and solution. The carbonyl on the central iron atom is semibridging, and this leads to a rotated structure between the bridged diiron center. IR studies reveal that all complexes are inert to protonation by HBF4·Et2O, but addition of acid to the pentacarbonyl complexes results in one-electron oxidation to yield the moderately stable cations [Fe3(CO)5(PPh3)2(μ-edt)2](+) and [Fe3(CO)5(κ(2)-diphosphine)(μ-edt)2](+), species which also result upon oxidation by [Cp2Fe][PF6]. The electrochemistry of the formally Fe(I)-Fe(II)-Fe(I) complexes has been investigated. Each undergoes a quasi-reversible oxidation, the potential of which is sensitive to phosphine substitution, generally occurring between 0.15 and 0.50 V, although [Fe3(CO)5(PPh3)2(μ-edt)2] is oxidized at -0.05 V. Reduction of all complexes is irreversible and is again sensitive to phosphine substitution, varying between -1.47 V for [Fe3(CO)7(μ-edt)2] and around -1.7 V for phosphine-substituted complexes. In their one-electron-reduced states, all complexes are catalysts for the reduction of protons to hydrogen, the catalytic overpotential being increased upon successive phosphine substitution. In comparison to the diiron complex [Fe2(CO)6(μ-edt)], [Fe3(CO)7(μ-edt)2] catalyzes proton reduction at 0.36 V less negative potentials. Electronic structure calculations have been carried out in order to fully elucidate the nature of the oxidation and reduction processes. In all complexes, the HOMO comprises an iron-iron bonding orbital localized between the two iron atoms not ligated by the semibridging carbonyl, while the LUMO is highly delocalized in nature and is antibonding between both pairs of iron atoms but also contains an antibonding dithiolate interaction. PMID:24748710

  2. Bioinspired Hydrogenase Models: The Mixed-Valence Triiron Complex [Fe3(CO)7(μ-edt)2] and Phosphine Derivatives [Fe3(CO)7–x(PPh3)x(μ-edt)2] (x = 1, 2) and [Fe3(CO)5(κ2-diphosphine)(μ-edt)2] as Proton Reduction Catalysts

    PubMed Central

    2014-01-01

    The mixed-valence triiron complexes [Fe3(CO)7–x(PPh3)x(μ-edt)2] (x = 0–2; edt = SCH2CH2S) and [Fe3(CO)5(κ2-diphosphine)(μ-edt)2] (diphosphine = dppv, dppe, dppb, dppn) have been prepared and structurally characterized. All adopt an anti arrangement of the dithiolate bridges, and PPh3 substitution occurs at the apical positions of the outer iron atoms, while the diphosphine complexes exist only in the dibasal form in both the solid state and solution. The carbonyl on the central iron atom is semibridging, and this leads to a rotated structure between the bridged diiron center. IR studies reveal that all complexes are inert to protonation by HBF4·Et2O, but addition of acid to the pentacarbonyl complexes results in one-electron oxidation to yield the moderately stable cations [Fe3(CO)5(PPh3)2(μ-edt)2]+ and [Fe3(CO)5(κ2-diphosphine)(μ-edt)2]+, species which also result upon oxidation by [Cp2Fe][PF6]. The electrochemistry of the formally Fe(I)–Fe(II)–Fe(I) complexes has been investigated. Each undergoes a quasi-reversible oxidation, the potential of which is sensitive to phosphine substitution, generally occurring between 0.15 and 0.50 V, although [Fe3(CO)5(PPh3)2(μ-edt)2] is oxidized at −0.05 V. Reduction of all complexes is irreversible and is again sensitive to phosphine substitution, varying between −1.47 V for [Fe3(CO)7(μ-edt)2] and around −1.7 V for phosphine-substituted complexes. In their one-electron-reduced states, all complexes are catalysts for the reduction of protons to hydrogen, the catalytic overpotential being increased upon successive phosphine substitution. In comparison to the diiron complex [Fe2(CO)6(μ-edt)], [Fe3(CO)7(μ-edt)2] catalyzes proton reduction at 0.36 V less negative potentials. Electronic structure calculations have been carried out in order to fully elucidate the nature of the oxidation and reduction processes. In all complexes, the HOMO comprises an iron–iron bonding orbital localized between the two iron atoms not ligated by the semibridging carbonyl, while the LUMO is highly delocalized in nature and is antibonding between both pairs of iron atoms but also contains an antibonding dithiolate interaction. PMID:24748710

  3. [μ-Bis(diphenyl-arsino)methane-1:2κAs:As']nona-carbonyl-1κC,2κC,3κC-[diphen-yl(phenyl-sulfanylmeth-yl)phosphine-3κP]-triangulo-triruthenium(0) chloro-form hemisolvate.

    PubMed

    Shawkataly, Omar Bin; Khan, Imthyaz Ahmed; Yeap, Chin Sing; Fun, Hoong-Kun

    2010-01-01

    The asymmetric unit of the title triangulo-triruthenium cluster, [Ru(3)(C(25)H(22)As(2))(C(19)H(17)PS)(CO)(9)]·0.5CHCl(3), contains of one mol-ecule of the triangulo-triruthenium complex and half a mol-ecule of the disordered (two positions of equal weight) chloro-form solvent. The bis-(diphenyl-arsino)methane ligand bridges an Ru-Ru bond and the monodentate phosphine ligand bonds to the third Ru atom. Both the arsine and phosphine ligands are equatorial with respect to the Ru(3) triangle. In addition, each Ru atom carries one equatorial and two axial terminal carbonyl ligands. The benzene ring of phenyl-thio-methyl is disordered over two positions with refined site occupancies of 0.788 (11) and 0.212 (11). In the crystal packing, mol-ecules are linked into chains along b axis by inter-molecular C-H⋯O hydrogen bonds. Weak inter-molecular C-H⋯π inter-actions further stabilize the crystal structure. PMID:21579685

  4. [μ-Bis(diphenyl­arsino)methane-1:2κ2 As:As′]nona­carbonyl-1κ3 C,2κ3 C,3κ3 C-[diphen­yl(phenyl­sulfanylmeth­yl)phosphine-3κP]-triangulo-triruthenium(0) chloro­form hemisolvate

    PubMed Central

    Shawkataly, Omar bin; Khan, Imthyaz Ahmed; Yeap, Chin Sing; Fun, Hoong-Kun

    2010-01-01

    The asymmetric unit of the title triangulo-triruthenium cluster, [Ru3(C25H22As2)(C19H17PS)(CO)9]·0.5CHCl3, contains of one mol­ecule of the triangulo-triruthenium complex and half a mol­ecule of the disordered (two positions of equal weight) chloro­form solvent. The bis­(diphenyl­arsino)methane ligand bridges an Ru—Ru bond and the monodentate phosphine ligand bonds to the third Ru atom. Both the arsine and phosphine ligands are equatorial with respect to the Ru3 triangle. In addition, each Ru atom carries one equatorial and two axial terminal carbonyl ligands. The benzene ring of phenyl­thio­methyl is disordered over two positions with refined site occupancies of 0.788 (11) and 0.212 (11). In the crystal packing, mol­ecules are linked into chains along b axis by inter­molecular C—H⋯O hydrogen bonds. Weak inter­molecular C—H⋯π inter­actions further stabilize the crystal structure. PMID:21579685

  5. Stereodynamics of sterically crowded metal-phosphine complexes: trans-[(t-Bu){sub 2}P(l-Pr)]{sub 2}MCl{sub 2} [M = Pt(II) and Pd(II)]. One-dimensional dynamic and two-dimensional chemical exchange NMR studies, X-ray crystallographic studies, molecular conformation trapping, and molecular mechanics calculations

    SciTech Connect

    DiMeglio, C.M.; Ahmed, K.J.; Luck, L.A.; Weltin, E.E.

    1992-10-29

    By using complementary techniques including dynamic NMR (DNMR) spectroscopy, X-ray crystallography, molecular conformation trapping and molecular mechanics calculations, incisive pictures of the stereodynamics of two sterically crowded Pd(II) and Pt(II) complexes have been elucidated. X-ray crystallography shows that the molecular geometry in the only crystalline modification (P2{sub 1}/a space group) of trans-[(t-Bu){sub 2}P(i-Pr)]{sub 2}PdCl{sub 2} (1) has C{sub i} symmetry. The isopropyl groups are mutually anti; the dihedral angle between the two P-CH bonds is 180{degrees}. For the isopropyl group on each phosphine ligand, one methyl group is anti and the other gauche ot the palladium atom. There are significant torsions about Pd-P,P-(i-Pr) and P-(t-Bu) bonds including a dihedral angle between proximate P-CH and Pd-Cl bonds of 21.6{degrees}. On the basis of the hypotheses that (a) when placed in solution, the conformation of each phosphine ligand of 1 will adopt an essentially exclusive preference for that in the crystal and (b) the two phosphines act essentially independently of each other, four stable diastereomeric equilibrium conformations are predicted. In two diastereomeric conformations, the isopropyl groups are mutually syn with dihedral angles between the P-CH bonds of 44{degrees} (C{sub 2} symmetry) and 0{degrees} (C{sub s} symmetry). In the other two diastereomeric forms, the isopropyl groups are mutually anti with dihedral angles between the P-CH bonds of 136{degrees} (C{sub 2} symmetry) and 180{degrees} (C{sub i} symmetry). Two-dimensional {sup 31}P({sup 1}H) NMR chemical exchange spectroscopy in conjunction with theoretical simulations of the one-dimensional {sup 31}P({sup 1}H) and {sup 13}C({sup 1}H)DNMR spectra do reveal the presence of four diastereomeric equilibrium conformations and allow elucidation of the preferred conformational interconversion pathways. 32 refs., 8 figs., 1 tab.

  6. (4-Ethenylphen-yl)diphenyl-phosphine selenide.

    PubMed

    Phasha, Zanele H; Makhoba, Sizwe; Muller, Alfred

    2012-09-01

    In the title mol-ecule, C(10)H(17)PSe, the P atom has a distorted tetra-hedral environment resulting in an effective cone angle of 165°. The benzene ring makes dihedral angles of 70.04 (8) and 77.28 (8)° with the phenyl rings, while the dihedral angle between the phenyl rings is 62.95 (8)°. In the crystal, mol-ecules are linked by C-H⋯π inter-actions. PMID:22969582

  7. Phosphine photochemistry in the atmosphere of Saturn

    NASA Astrophysics Data System (ADS)

    Kaye, J. A.; Strobel, D. F.

    1984-09-01

    The photochemistry of PH3 in the atmosphere of Saturn is studied, including the effects of coupling with the photochemistries of NH3 and hydrocarbons. The vertical concentration of PH3 is found to be extremely sensitive to the eddy diffusion coefficient (K) profile used. If K is roughly 10,000 sq cm/sec in the upper troposphere, PH3 should be depleted there with a scale height of about 3.5 km. An upper limit of 100,000 sq cm/sec is estimated for K. If the gas phase concentration of P2H4 can be neglected, production of molecular phophorus is very unlikely unless the spin-forbidden recombination reaction PH+H2+M - PH3+M occurs with an exceptionally low rate. Coupling of PH3 and hydrocarbon photochemistries is very important. Possible observable amounts of the organophosphorus molecules CH3PH2 and HCP are tentatively predicted.

  8. 40 CFR 721.6020 - Phosphine, dialkylyphenyl.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... with information on the location and availability of MSDSs does not apply when an MSDS is not required under § 721.72(c). The provision of § 721.72(g) requiring placement of specific information in an MSDS does not apply when an MSDS is not required under § 721.72(c). (iii) Disposal. Requirements...

  9. 40 CFR 721.6020 - Phosphine, dialkylyphenyl.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... with information on the location and availability of MSDSs does not apply when an MSDS is not required under § 721.72(c). The provision of § 721.72(g) requiring placement of specific information in an MSDS does not apply when an MSDS is not required under § 721.72(c). (iii) Disposal. Requirements...

  10. 40 CFR 721.6020 - Phosphine, dialkylyphenyl.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... with information on the location and availability of MSDSs does not apply when an MSDS is not required under § 721.72(c). The provision of § 721.72(g) requiring placement of specific information in an MSDS does not apply when an MSDS is not required under § 721.72(c). (iii) Disposal. Requirements...

  11. 40 CFR 721.6020 - Phosphine, dialkylyphenyl.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... with information on the location and availability of MSDSs does not apply when an MSDS is not required under § 721.72(c). The provision of § 721.72(g) requiring placement of specific information in an MSDS does not apply when an MSDS is not required under § 721.72(c). (iii) Disposal. Requirements...

  12. 40 CFR 721.6020 - Phosphine, dialkylyphenyl.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... with information on the location and availability of MSDSs does not apply when an MSDS is not required under § 721.72(c). The provision of § 721.72(g) requiring placement of specific information in an MSDS does not apply when an MSDS is not required under § 721.72(c). (iii) Disposal. Requirements...

  13. Phosphine photochemistry in the atmosphere of Saturn

    NASA Technical Reports Server (NTRS)

    Kaye, J. A.; Strobell, D. F.

    1984-01-01

    The photochemistry of PH3 in the atmosphere of Saturn is studied, including the effects of coupling with the photochemistries of NH3 and hydrocarbons. The vertical concentration of PH3 is found to be extremely sensitive to the eddy diffusion coefficient (K) profile used. If K is roughly 10,000 sq cm/sec in the upper troposphere, PH3 should be depleted there with a scale height of about 3.5 km. An upper limit of 100,000 sq cm/sec is estimated for K. If the gas phase concentration of P2H4 can be neglected, production of molecular phophorus is very unlikely unless the spin-forbidden recombination reaction PH+H2+M - PH3+M occurs with an exceptionally low rate. Coupling of PH3 and hydrocarbon photochemistries is very important. Possible observable amounts of the organophosphorus molecules CH3PH2 and HCP are tentatively predicted.

  14. Phosphine-free synthesis of high-quality reverse type-I ZnSe/CdSe core with CdS/CdxZn1 - xS/ZnS multishell nanocrystals and their application for detection of human hepatitis B surface antigen

    NASA Astrophysics Data System (ADS)

    Shen, Huaibin; Yuan, Hang; Niu, Jin Zhong; Xu, Shasha; Zhou, Changhua; Ma, Lan; Li, Lin Song

    2011-09-01

    Highly photoluminescent (PL) reverse type-I ZnSe/CdSe nanocrystals (NCs) and ZnSe/CdSe/CdS/CdxZn1 - xS/ZnS core/multishell NCs were successfully synthesized by a phosphine-free method. By this low-cost, 'green' synthesis route, more than 10 g of high-quality ZnSe/CdSe/CdS/CdxZn1 - xS/ZnS NCs were synthesized in a large scale synthesis. After the overgrowth of a CdS/CdxZn1 - xS/ZnS multishell on ZnSe/CdSe cores, the PL quantum yields (QYs) increased from 28% to 75% along with the stability improvement. An amphiphilic oligomer was used as a surface coating agent to conduct a phase transfer experiment, core/multishell NCs were dissolved in water by such surface modification and the QYs were still kept above 70%. The as-prepared water dispersible ZnSe/CdSe/CdS/CdxZn1 - xS/ZnS core/multishell NCs not only have high fluorescence QYs but also are extremely stable in various physiological conditions. Furthermore, a biosensor system (lateral flow immunoassay system, LFIA) for the detection of human hepatitis B surface antigen (HBsAg) was developed by using this water-soluble core/multishell NCs as a fluorescent label and a nitrocellulose filter membrane for lateral flow. The result showed that such ZnSe/CdSe/CdS/CdxZn1 - xS/ZnS core/multishell NCs were excellent fluorescent labels to detect HBsAg. The sensitivity of HBsAg detection could reach as high as 0.05 ng ml - 1.

  15. Development of an extractive spectrophotometric method for estimation of uranium in ore leach solutions using 2-ethylhexyl phosphonic acid-mono-2-ethylhexyl ester (PC88A) and tri-n-octyl phosphine oxide (TOPO) mixture as extractant and 2-(5-bromo-2-pyridylozo)-5-diethyl aminophenol (Br-PADAP) as chromophore.

    PubMed

    Biswas, Sujoy; Pathak, P N; Roy, S B

    2012-06-01

    An extractive spectrophotometric analytical method has been developed for the determination of uranium in ore leach solution. This technique is based on the selective extraction of uranium from multielement system using a synergistic mixture of 2-ethylhexyl phosphonic acid-mono-2-ethylhexyl ester (PC88A) and tri-n-octyl phosphine oxide (TOPO) in cyclohexane and color development from the organic phase aliquot using 2-(5-Bromo-2-pyridylazo)-5-diethyl aminophenol (Br-PADAP) as chromogenic reagent. The absorption maximum (λ(max)) for UO(2)(2+)-Br-PADAP complex in organic phase samples, in 64% (v/v) ethanol containing buffer solution (pH 7.8) and 1,2-cyclohexylenedinitrilotetraacetic acid (CyDTA) complexing agent, has been found to be at 576 nm (molar extinction coefficient, ɛ: 36,750 ± 240 L mol(-1)cm(-1)). Effects of various parameters like stability of complex, ethanol volume, ore matrix, interfering ions etc. on the determination of uranium have also been evaluated. Absorbance measurements as a function of time showed that colored complex is stable up to > 24h. Presence of increased amount of ethanol in colored solution suppresses the absorption of a standard UO(2)(2+)-Br-PADAP solution. Analyses of synthetic standard as well as ore leach a solution show that for 10 determination relative standard deviation (RSD) is < 2%. The accuracy of the developed method has been checked by determining uranium using standard addition method and was found to be accurate with a 98-105% recovery rate. The developed method has been applied for the analysis of a number of uranium samples generated from uranium ore leach solutions and results were compared with standard methods like inductively coupled plasma emission spectrometry (ICPAES). The determined values of uranium concentrations by these methods are within ± 2%. This method can be used to determine 2.5-250 μg mL(-1) uranium in ore leach solutions with high accuracy and precision. PMID:22381794

  16. Silica with immobilized phosphinic acid-derivative for uranium extraction.

    PubMed

    Budnyak, Tetyana M; Strizhak, Alexander V; Gładysz-Płaska, Agnieszka; Sternik, Dariusz; Komarov, Igor V; Kołodyńska, Dorota; Majdan, Marek; Tertykh, Valentin А

    2016-08-15

    A novel adsorbent benzoimidazol-2-yl-phenylphosphinic acid/aminosilica adsorbent (BImPhP(O)(OH)/SiO2NH2) was prepared by carbonyldiimidazole-mediated coupling of aminosilica with 1-carboxymethylbenzoimidazol-2-yl-phenylphosphinic acid. It was obtained through direct phosphorylation of 1-cyanomethylbenzoimidazole by phenylphosphonic dichloride followed by basic hydrolysis of the nitrile. The obtained sorbent was well characterized by physicochemical methods, such as differential scanning calorimetry-mass spectrometry (DSC-MS), surface area and pore distribution analysis (ASAP), scanning electron microscopy (SEM), X-ray photoelectron (XPS) and Fourier transform infrared (FTIR) spectroscopies. The adsorption behavior of the sorbent and initial silica gel as well as aminosilica gel with respect to uranium(VI) from the aqueous media has been studied under varying operating conditions of pH, concentration of uranium(VI), contact time, and desorption in different media. The synthesized material was found to show an increase in adsorption activity with respect to uranyl ions in comparison with the initial compounds. In particular, the highest adsorption capacity for the obtained modified silica was found at the neutral pH, where one gram of the adsorbent can extract 176mg of uranium. Under the same conditions the aminosilica extracts 166mg/g, and the silica - 144mg/g of uranium. In the acidic medium, which is common for uranium nuclear wastes, the synthesized adsorbent extracts 27mg/g, the aminosilica - 16mg/g, and the silica - 14mg/g of uranium. It was found that 15% of uranium ions leached from the prepared material in acidic solutions, while 4% of uranium can be removed in a phosphate solution. PMID:27177215

  17. [4-(Dimethyl-amino)-phen-yl]diphenyl-phosphine selenide.

    PubMed

    Davis, Wade L; Muller, Alfred

    2012-11-01

    In the title compound, C(20)H(20)NPSe, the P atom lies in a distorted tetra-hedral environment. The Tolman cone angle is 157° indicating steric crowding at this atom. In the crystal, weak C-H⋯Se inter-actions create linked dimeric units and C-H⋯π inter-actions are also observed. PMID:23284470

  18. Tris(4-methyl-phen-yl)phosphine selenide.

    PubMed

    Muller, Alfred

    2010-01-01

    In the title mol-ecule, C(21)H(21)PSe or PSe(C(7)H(7))(3), the P atom has a distorted PSeC(3) tetra-hedral environment, formed by the Se atom [P=Se = 2.1119 (5) Å] and three aryl rings. Two short intra-molecular C-H⋯Se contacts occur. In the crystal, weak inter-molecular C-H⋯Se inter-actions link the mol-ecules into zigzag double chains propagating in [100]. The previous report of this structure [Zhdanov et al. (1953 ▶). Dokl. Akad. Nauk SSSR (Russ.) (Proc. Nat. Acad. Sci. USSR), 92, 983-985] contained no geometrical data. PMID:21522754

  19. 7 CFR 305.7 - Phosphine treatment schedules.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...-4 NAP1 50 or above 2.1 grams/cubic meter 120 T203-g-3 NAP 50 or above 2.1 grams/cubic meter 120 T301-a-6 NAP 50 or above 60 grams/1000 ft3 120 T301-d-1-2 NAP 50 or above 36 grams/1000 ft3 72 T311 NAP 50 or above 60 grams/1000 ft3 168 1 Normal atmospheric pressure....

  20. One-Pot Phosphine-Catalyzed Syntheses of Quinolines

    PubMed Central

    Khong, San; Kwon, Ohyun

    2012-01-01

    In this study we developed an efficient one-pot procedure for the preparation of 3-substituted and 3,4-disubstituted quinolines from stable starting materials (activated acetylenes reacting with o-tosylamidobenzaldehydes and o-tosylamidophenones, respectively) under mild conditions. The reaction appears to operate under a general base catalysis mechanism, instigated by the β-phosphonium enoate α-vinyl anion generated in situ through nucleophilic addition of PPh3 to the activated alkyne. Michael addition of the deprotonated tosylamides to the activated alkynes and subsequent rapid aldol cyclization led to the formation of labile N-tosyldihydroquinoline intermediates. Driven by aromatization, detosylation of the dihydroquinoline intermediates occurred readily in the presence of dilute aqueous HCl to give the final quinoline products. PMID:22928667

  1. 40 CFR 180.225 - Phosphine; tolerances for residues.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    .... Commodity Parts per million Almond 0.1 Avocado 0.01 Banana 0.01 Barley, grain 0.1 Cabbage, Chinese, bok choy 0.01 Cabbage, Chinese, napa 0.01 Cacao bean, dried bean 0.1 Cashew 0.1 Citron, citrus 0.01...

  2. 40 CFR 180.225 - Phosphine; tolerances for residues.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    .... Commodity Parts per million Almond 0.1 Avocado 0.01 Banana 0.01 Barley, grain 0.1 Cabbage, Chinese, bok choy 0.01 Cabbage, Chinese, napa 0.01 Cacao bean, dried bean 0.1 Cashew 0.1 Citron, citrus 0.01...

  3. 40 CFR 180.225 - Phosphine; tolerances for residues.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    .... Commodity Parts per million Almond 0.1 Avocado 0.01 Banana 0.01 Barley, grain 0.1 Cabbage, Chinese, bok choy 0.01 Cabbage, Chinese, napa 0.01 Cacao bean, dried bean 0.1 Cashew 0.1 Citron, citrus 0.01...

  4. 40 CFR 180.225 - Phosphine; tolerances for residues.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    .... Commodity Parts per million Almond 0.1 Avocado 0.01 Banana 0.01 Barley, grain 0.1 Cabbage, Chinese, bok choy 0.01 Cabbage, Chinese, napa 0.01 Cacao bean, dried bean 0.1 Cashew 0.1 Citron, citrus 0.01...

  5. 40 CFR 180.225 - Phosphine; tolerances for residues.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    .... Commodity Parts per million Almond 0.1 Avocado 0.01 Banana 0.01 Barley, grain 0.1 Cabbage, Chinese, bok choy 0.01 Cabbage, Chinese, napa 0.01 Cacao bean, dried bean 0.1 Cashew 0.1 Citron, citrus 0.01...

  6. Phosphine-Mediated Iterative Arene Homologation Using Allenes.

    PubMed

    Zhang, Kui; Cai, Lingchao; Jiang, Xing; Garcia-Garibay, Miguel A; Kwon, Ohyun

    2015-09-01

    A PPh3-mediated multicomponent reaction between o-phthalaldehydes, nucleophiles, and monosubstituted allenes furnishes functionalized non-C2-symmetric naphthalenes in synthetically useful yields. When the o-phthalaldehydes were reacted with 1,3-disubstituted allenes in the presence of PPh2Et, naphthalene derivatives were also obtained in up to quantitative yields. The mechanism of the latter transformation is straightforward: aldol addition followed by Wittig olefination and dehydration. The mechanism of the former is a tandem ?-umpolung/aldol/Wittig/dehydration process, as established by preparation of putative reaction intermediates and mass spectrometric analysis. This transformation can be applied iteratively to prepare anthracenes and tetracenes using carboxylic acids as pronucleophiles. PMID:26295504

  7. Response of light brown apple moth to oxygenated phosphine fumigation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The light brown apple moth (LBAM), Epiphyas postvittana (Walker), poses a serious threat to California agriculture and is currently quarantined by several major trading partners. Fumigation is the only tool to assure pest-free postharvest vegetable and fruit products. However, current fumigants for ...

  8. The Reduction of a Nitrile (CN) Group by Sodium Borohydride. The Preparation of Phosphine--Amine and Phosphine--Iimidate Complesex of Tungsten Carbonyl.

    ERIC Educational Resources Information Center

    Faust, Kristen E.; Storhoff, Bruce N.

    1989-01-01

    Describes an experiment for advanced-level undergraduate students for extending student experiences involving recording and interpreting infrared (IR) and nuclear magnetic resonance (NMR) spectra from reactions of organometallic compounds. Experimental procedures, analyses and structural assignments, and suggestions for extension and modification…

  9. Paramagnetic Rh(III) complexes from reactions of phosphines with hydride-bridged and nonbridged rhodium phthalocyanine dimers: Metal-to-ligand charge transfer induced by phosphines

    SciTech Connect

    Chen, M.J.; Utschig, L.M.; Rathke, J.W.

    1998-11-02

    The paramagnetic rhodium phthalocyanine complex (RPc)(PMe{sub 3}){sub 2}Rh (4) (RPc = dianion of 1,4,8,11,15,18,22,25-octa-n-pentylphthalocyanine) has been prepared by the reaction of trimethylphosphine (PMe{sub 3}) with hydride-bridged and nonbridged rhodium phthalocyanine dimers. The reaction of the {mu}-hydrido complex (RPcH)Rh({mu}-H)Rh(RPc) (5) (RPcH = RPc with one of its meso nitrogens protonated) with PMe{sub 3} at {minus}10 C produces (RPc)(PMe{sub 3})RhH (6), which further reacts with PMe{sub 3} to produce 4 and H{sub 2} at higher temperatures. If the solution of 6 is allowed to warm in the absence of free PMe{sub 3}, H{sub 2} is also liberated and 6 is converted to an equal number of moles of 4 and [(RPc)Rh]{sub 2}(PMe{sub 3}) (7). In contrast, the reaction of 5 with pyridine (py) produces (RPc)(py)-RhH (11), which does not react with additional pyridine. Alternatively, 4 is generated by the reaction of the Rh-Rh bonded dimer [(RPc)Rh]{sub 2} (1) with PMe{sub 3}. In this reaction, the formation of 7 as an intermediate may be shown by the titration of 1 with PMe{sub 3}. Complex 1 reacts with 4 to produce (RPc)Rh{sup {minus}} (10) and (RPc)(PMe{sub 3}){sub 2}-Rh{sup +} (9). A redox exchange between 4 and 9 ensues. The cobalt analogue of 4, i.e., (RPc)(PMe{sub 3}){sub 2}Co (12), was generated reversibly by the reaction of (RPc)Co (13) with PMe{sub 3} at low temperatures. The {sup 1}H NMR and the ESR spectra of 4, 12, and 13 indicate that while 13 is a metal-centered radical, 4 and 12 are best described as ligand-centered radicals.

  10. Enhanced lasing properties of dissymmetric Eu(III) complex with bidentate phosphine ligands.

    PubMed

    Nakamura, Kazuki; Hasegawa, Yasuchika; Kawai, Hideki; Yasuda, Naoki; Kanehisa, Nobuko; Kai, Yasushi; Nagamura, Toshihiko; Yanagida, Shozo; Wada, Yuji

    2007-04-26

    The luminescent and lasing properties of Eu(III) complexes were enhanced by using an dissymmetric Eu(III) complex. The photophysical properties (the emission spectral shapes, the emission lifetimes, the emission quantum yields, and the stimulated emission cross section (SEC)) were found to be dependent on the geometrical structures of Eu(III) complexes. The geometrical structures of Eu(III) complexes were determined by X-ray single crystal analyses. The symmetrical group of Eu(hfa)3(BIPHEPO) (tris(hexafluoroacetylacetonato)europium(III) 1,1'-biphenyl-2,2'-diylbis(diphenylphosphine oxide)) was found to be C1, which was more dissymmetric than Eu(hfa)3(TPPO)2 (tris(hexafluoroacetylacetonato)europium(III) 1,2-phenylenebis(diphenylphosphine oxide): C2 symmetry) and Eu(hfa)3(OPPO)2 (tris(hexafluoroacetylacetonato)europium(III) 1,2-phenylenebis(diphenylphosphine oxide): C2 symmetry). The analytical data were supported by Judd-Ofelt analysis. The most dissymmetrical Eu(III) complex, Eu(hfa)3(BIPHEPO), showed large electron transition probability and large SEC (4.64 x 10(-20) cm2). The SEC of Eu(hfa)3(BIPHEPO) was superior to even the values of Nd-glass laser for practical use (1.6-4.5 x 10(-20) cm2). The lasing properties of Eu(III) complexes in polymer thin film were measured by photopumping of a Nd:YAG laser (355 nm). The threshold energy of lasing oscillation was found to be 0.05 mJ. The increasing rate of the lasing intensity of Eu(hfa)3(BIPHEPO) as a function of the excitation energy was much larger than that of Eu(hfa)3(TPPO)2 and Eu(hfa)3(OPPO)2. The dissymmetrical structure of Eu(hfa)3(BIPHEPO) promoted the enhancement of the lasing property. PMID:17391010

  11. SEASONAL AND SPATIAL CHANGES IN INSECT DENSITY IN COMMERCIAL ELEVATOR BINS: IMPLICATIONS FOR PHOSPHINE FUMIGATION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Results of a 5-year, area-wide IPM program for managing insect pests in commercial grain elevators in Kansas and Oklahoma showed that insects generally invaded stored grain from the top of the grain mass. In stored wheat, the rusty grain beetle was the most common insect species from June-September,...

  12. The Mechanochemical Reaction of Palladium(II) Chloride with a Bidentate Phosphine

    ERIC Educational Resources Information Center

    Berry, David E.; Carrie, Philippa; Fawkes, Kelli L.; Rebner, Bruce; Xing, Yao

    2010-01-01

    This experiment describes the reaction of palladium(II) chloride with 1,5-bis(diphenylphosphino)pentane by grinding the two powders together in the solid state. The product is the precursor for the metalation reaction at one of the methylene carbon atoms of the ligand's backbone. The final product is known to be a catalyst for Suzuki-Miyaura…

  13. Synthesis, structural characterization and reactivity of a bis(phosphine)(silyl) platinum(II) complex

    NASA Astrophysics Data System (ADS)

    Li, Yong-Hua; Yang, Cheng-Long; Lai, Wen-Yong; Huang, Zheng-Feng; Wang, Shi; Wang, Lian-Hui; Huang, Wei

    2015-10-01

    Treatment of 1,2-C6H4(SiH3)(SiH3) (1) with Pt(dcpe)(PEt3)2 (dcpe = Cy2PCH2CH2PCy2) in dry toluene at room temperature in the ratio of 1:1 leads to the complex {1,2-C6H4(SiH2)(SiH2)}PtII(dcpe) (2), which can react with proton organic reagent bearing hydroxy group with low steric hindrance to form a tetra-alkoxy substituted silyl platinum(II) compound (3). The structures of complexes (2) and (3) were unambiguously determined by multinuclear NMR spectroscopic studies and single crystal X-ray analysis.

  14. Luminescence in phosphine-stabilized copper chalcogenide cluster molecules--a comparative study.

    PubMed

    Eichhöfer, Andreas; Buth, Gernot; Lebedkin, Sergei; Kühn, Michael; Weigend, Florian

    2015-10-01

    The electronic properties of a series of eight copper chalcogenide clusters including [Cu12S6(dpppt)4] (dpppt = Ph2P(CH2)5PPh2), [Cu12Se6(dppo)4] (dppo = Ph2P(CH2)8PPh2), [Cu12S6(dppf)4] (dppf = Ph2PCpFeCpPPh2), [Cu12S6(PPh2Et)8], [Cu12S6(PEt3)8], [Cu24S12(PEt2Ph)12], [Cu20S10(PPh3)8], and [Cu20S10(P(t)Bu3)8] were investigated by absorption and photoluminescence (PL) spectroscopy as well as time-dependent density functional theory calculations. Major features of the experimental electronic absorption spectra are generally well-reproduced by the spectra simulated from the calculated singlet transitions. Visualization of the nonrelaxed difference densities indicates that for all compounds transitions at higher energies (above ∼2.5 eV, i.e., below ∼495 nm) predominantly involve excitations of electrons from orbitals of the cluster core to ligand orbitals. Conversely, the natures of the lower-energy transitions are found to be highly sensitive to the specifics of the ligand surface. Bright red PL (centered at ∼650-700 nm) in the solid state at ambient temperature is found for complexes with all 'Cu12S6' (E = S, Se) cores as well as the dimeric 'Cu24S12', although in [Cu12S6(dppf)4], the PL appears to be efficiently quenched by the ferrocenyl groups. Of the two isomeric 'Cu20S10' complexes the prolate cluster [Cu20S10(PPh3)8] shows a broad emission that is centered at ∼820 nm, whereas the oblate cluster [Cu20S10(P(t)Bu3)8] displays a relatively weak orange emission at ∼575 nm. The emission of all complexes decays on the time scale of a few microseconds at ambient temperature. A very high photostability is quantitatively estimated for the representative complex [Cu12S6(dpppt)4] under anaerobic conditions. PMID:26378617

  15. CHIRAL-AT-METAL OSMIUM(VI) PHOSPHINE COMPLEXES. (R829553)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  16. Direct Hydrogenation of Biobased Carboxylic Acids Mediated by a Nitrogen-centered Tridentate Phosphine Ligand.

    PubMed

    Deng, Li; Kang, Bin; Englert, Ulli; Klankermayer, Jrgen; Palkovits, Regina

    2016-01-01

    A novel nitrogen-centered tridentate ligand was identified from a series of multidentate ligands and applied for the direct hydrogenation of 9 biogenic acids into alcohols, lactones and esters with high yields. Comparison of substrates and ruthenium precursors suggested that the Ru(II) hydride cationic species was more active to transform acids than the corresponding lactone or esters. PMID:26749183

  17. trans-(Ethene-1,2-di-yl)bis-(diphenyl-phosphine selenide).

    PubMed

    Phasha, Zanele; Makhoba, Sizwe; Muller, Alfred

    2012-01-01

    In the title mol-ecule, C(26)H(22)P(2)Se(2), both P atoms have distorted tetra-hedral environments, resulting in effective cone angles of 177 and 174°. Inversion twinning was detected and refined to a ratio of 0.35:0.65. Weak inter-molecular C-H⋯Se inter-actions are observed. PMID:22259547

  18. rac-[2-(Dicyclohexylphosphanyl)phenyl](phenyl)phosphinic diisopropyl-amide-borane hemihydrate.

    PubMed

    Evans, Stephen J; Renison, C Alicia; Williams, D Bradley G; Muller, Alfred

    2013-02-01

    In the title compound, C(30)H(48)BNOP(2)·0.5H(2)O, the water molecule is disordered about an inversion centre. Both phospho-rus atoms shows distortions in their tetra-hedral environments with the cyclo-hexyl substituents disordered over two orientations in a 0.851 (3):0.149 (3) occupancy ratio. The crystal structure is assembled via O-H⋯O inter-actions between pairs of phosphininc amide mol-ecules and water molecules, creating hydrogen-bonded dimers with graph-set R(2) (4)(8) along [001]. Weak C-H⋯O inter-actions are also observed. PMID:23424555

  19. Bis(2,4-dimeth-oxy-phen-yl)(phen-yl)phosphine selenide.

    PubMed

    Muller, Alfred

    2010-01-01

    In the title mol-ecule, C(22)H(23)O(4)PSe, the P atom has a distorted tetra-hedral environment formed by the selenide atom [P=Se = 2.1219 (5) Å] and three aryl rings. The orientations of the meth-oxy groups in the two 2,4-dimeth-oxy-phenyl ligands are distinct, as seen from the torsion angles: C-C-O-C = 14.7 (3) and 175.97 (17)° in one ligand, and -9.1 (2) and 5.1 (3)° in the other. In the crystal, weak inter-molecular C-H⋯Se inter-actions link the mol-ecules into zigzag chains propagated in [010]. PMID:21522806

  20. Bis(2-meth-oxy-phen-yl)(phen-yl)phosphine selenide.

    PubMed

    Muller, Alfred

    2010-01-01

    The title compound, C(20)H(19)O(2)PSe or SePPh(2-OMe-C(6)H(3))(2), crystallizes with two distinct orientations for the meth-oxy groups. The Se=P bond is 2.1170 (7) Å and the cone angle is 176.0°. Intra-molecular C-H⋯Se inter-actions occur. In the crystal, mol-ecules are linked by inter-molecular C-H⋯Se inter-actions. PMID:21522797

  1. Dicyclo-hex-yl[4-(dimethyl-amino)-phen-yl]phosphine selenide.

    PubMed

    Phasha, Zanele H; Makhoba, Sizwe; Muller, Alfred

    2012-01-01

    In the title mol-ecule, C(20)H(32)NPSe, the P atom has a distorted tetra-hedral environment resulting in an effective cone angle of 172°. Weak inter-molecular C-H⋯Se inter-actions are observed. PMID:22259525

  2. (2-{[2-(diphenyl-phosphino)phen-yl]thio}-phen-yl)diphenyl-phosphine sulfide.

    PubMed

    Alvarez-Larena, Angel; Martinez-Cuevas, Francisco J; Flor, Teresa; Real, Juli

    2012-11-01

    In the title compound, C(36)H(28)P(2)S(2), the dihedral angle between the central benzene rings is 66.95 (13)°. In the crystal, molecules are linked via C(ar)-H⋯π and π-π inter-actions [shortest centroid-centroid distance between benzene rings = 3.897 (2) Å]. PMID:23284423

  3. Synthesis of diaryl ketones via a phosphine-free Fukuyama reaction.

    PubMed

    Kunchithapatham, Kamala; Eichman, Chad C; Stambuli, James P

    2011-12-21

    The synthesis of unsymmetrical diaryl ketones via the Fukuyama coupling of thioesters and organozinc reagents is described. Typically, the synthesis of diaryl ketones using this methodology provides low yields. The simple complex, Pd(dba)(2), was found to convert a variety of aryl thioesters to diaryl ketones in good yields. PMID:22037521

  4. Nucleophilic Substitution Reactions Using Phosphine Nucleophiles: An Introduction to Phosphorus-31 NMR

    ERIC Educational Resources Information Center

    Sibbald, Paul A.

    2015-01-01

    Nuclear magnetic resonance (NMR) spectroscopy is commonly used in modern synthetic chemistry to monitor the conversion of reactants to products. Since instruction in the use of NMR spectroscopy typically does not occur until after the introduction of nucleophilic substitution reactions, organic chemistry students are not able to take advantage of

  5. Design and Characterization of Phosphine Iron Hydrides: Toward Hydrogen-Producing Catalysts.

    PubMed

    Weber, Katharina; Weyhermüller, Thomas; Bill, Eckhard; Erdem, Özlen F; Lubitz, Wolfgang

    2015-07-20

    Diamagnetic iron chloro compounds [(P(Ph)2N(Ph)2)FeCp*Cl] [1Cl] and [(P(Cy)2N(Ph)2)FeCp*Cl] [2Cl] and the corresponding hydrido complexes [(P(Ph)2N(Ph)2)FeCp*H] [1H] and [(P(Cy)2N(Ph)2)FeCp*H] [2H] have been synthesized and characterized by NMR spectroscopy, electrochemical studies, electronic absorption, and (57)Fe Mössbauer spectroscopy (P(Ph)2N(Ph)2 = 1,3,5,7-tetraphenyl-1,5-diphospha-3,7-diazacyclooctane, P(Cy)2N(Ph)2 = 1,5-dicyclohexyl-3,7-diphenyl-1,5-diphospha-3,7-diazacyclooctane, Cp* = pentamethylcyclopentadienyl). Molecular structures of [2Cl], [1H], and [2H], derived from single-crystal X-ray diffraction, revealed that these compounds have a typical piano-stool geometry. The results show that the electronic properties of the hydrido complexes are strongly influenced by the substituents at the phosphorus donor atoms of the P(R)2N(Ph)2 ligand, whereas those of the chloro complexes are less affected. These results illustrate that the hydride is a strong-field ligand, as compared to chloride, and thus leads to a significant degree of covalent character of the iron hydride bonds. This is important in the context of possible catalytic intermediates of iron hydrido species, as proposed for the catalytic cycle of [FeFe] hydrogenases and other synthetic catalysts. Both hydrido compounds [1H] and [2H] show enhanced catalytic currents in cyclic voltammetry upon addition of the strong acid trifluoromethanesulfonimide [NHTf2] (pKa(MeCN) = 1.0). In contrast to the related complex [(P(tBu)N(Bn))2FeCp(C6F5)H], which was reported by Liu et al. (Nat. Chem. 2013, 5, 228-233) to be an electrocatalyst for hydrogen splitting, the here presented hydride complexes [1H] and [2H] show the tendency for electrocatalytic hydrogen production. Hence, the catalytic direction of this class of monoiron compounds can be reversed by specific ligand modifications. PMID:26132460

  6. Complexes between hypohalous acids and phosphine derivatives. Pnicogen bond versus halogen bond versus hydrogen bond.

    PubMed

    Li, Qingzhong; Zhu, Hongjie; Zhuo, Hongying; Yang, Xin; Li, Wenzuo; Cheng, Jianbo

    2014-11-11

    The complexes of HOBr:PH2Y (Y=H, F, Cl, Br, CH3, NH2, OH, and NO2), HOCl:PH2F, and HOI:PH2F have been investigated with ab initio calculations at the MP2/aug-cc-pVTZ level. Four types of structures (1, 2, 3a, and 3b) were observed for these complexes. 1 is stabilized by an O⋯P pnicogen bond, 2 by a P⋯X halogen bond, 3a by a H⋯P hydrogen bond and a P⋯X pnicogen bond, and 3b by H⋯P and H⋯Br hydrogen bonds. Their relative stability is related to the halogen X of HOX and the substituent Y of PH2Y. These structures can compete with interaction energy of -10.22∼-29.40 kJ/mol. The HO stretch vibration shows a small red shift in 1, a small irregular shift in 2, but a prominent red shift in 3a and 3b. The XO stretch vibration exhibits a smaller red shift in 1, a larger red shift in 2, but an insignificant blue shift in 3a and 3b. The PY stretch vibration displays a red shift in 1 but a blue shift in 2, 3a, and 3b. The formation mechanism, stability, and properties of these structures have been analyzed with molecular electrostatic potentials, orbital interactions, and non-covalent interaction index. PMID:24878434

  7. Complexes between hypohalous acids and phosphine derivatives. Pnicogen bond versus halogen bond versus hydrogen bond

    NASA Astrophysics Data System (ADS)

    Li, Qingzhong; Zhu, Hongjie; Zhuo, Hongying; Yang, Xin; Li, Wenzuo; Cheng, Jianbo

    2014-11-01

    The complexes of HOBr:PH2Y (Y = H, F, Cl, Br, CH3, NH2, OH, and NO2), HOCl:PH2F, and HOI:PH2F have been investigated with ab initio calculations at the MP2/aug-cc-pVTZ level. Four types of structures (1, 2, 3a, and 3b) were observed for these complexes. 1 is stabilized by an O⋯P pnicogen bond, 2 by a P⋯X halogen bond, 3a by a H⋯P hydrogen bond and a P⋯X pnicogen bond, and 3b by H⋯P and H⋯Br hydrogen bonds. Their relative stability is related to the halogen X of HOX and the substituent Y of PH2Y. These structures can compete with interaction energy of -10.22 ∼ -29.40 kJ/mol. The Hsbnd O stretch vibration shows a small red shift in 1, a small irregular shift in 2, but a prominent red shift in 3a and 3b. The Xsbnd O stretch vibration exhibits a smaller red shift in 1, a larger red shift in 2, but an insignificant blue shift in 3a and 3b. The Psbnd Y stretch vibration displays a red shift in 1 but a blue shift in 2, 3a, and 3b. The formation mechanism, stability, and properties of these structures have been analyzed with molecular electrostatic potentials, orbital interactions, and non-covalent interaction index.

  8. Nucleophilic Substitution Reactions Using Phosphine Nucleophiles: An Introduction to Phosphorus-31 NMR

    ERIC Educational Resources Information Center

    Sibbald, Paul A.

    2015-01-01

    Nuclear magnetic resonance (NMR) spectroscopy is commonly used in modern synthetic chemistry to monitor the conversion of reactants to products. Since instruction in the use of NMR spectroscopy typically does not occur until after the introduction of nucleophilic substitution reactions, organic chemistry students are not able to take advantage of…

  9. Chain-end-functionalized polyphosphazenes via a one-pot phosphine-mediated living polymerization.

    PubMed

    Wilfert, Sandra; Henke, Helena; Schoefberger, Wolfgang; Brüggemann, Oliver; Teasdale, Ian

    2014-06-01

    A simple polymerization of trichlorophosphoranimine (Cl3 P = N-SiMe3 ) mediated by functionalized triphenylphosphines is presented. In situ initiator formation and the subsequent polymerization progress are investigated by (31) P NMR spectroscopy, demonstrating a living cationic polymerization mechanism. The polymer chain lengths and molecular weights of the resulting substituted poly(organo)phosphazenes are further studied by (1) H NMR spectroscopy and size exclusion chromatography. This strategy facilitates the preparation of polyphosphazenes with controlled molecular weights and specific functional groups at the α-chain end. Such well-defined, mono-end-functionalized polymers have great potential use in bioconjugation, surface modification, and as building blocks for complex macromolecular constructs. PMID:24700544

  10. Chain-End-Functionalized Polyphosphazenes via a One-Pot Phosphine-Mediated Living Polymerization

    PubMed Central

    Wilfert, Sandra; Henke, Helena; Schoefberger, Wolfgang; Brüggemann, Oliver; Teasdale, Ian

    2014-01-01

    A simple polymerization of trichlorophosphoranimine (Cl3P = N−SiMe3) mediated by functionalized triphenylphosphines is presented. In situ initiator formation and the subsequent polymerization progress are investigated by 31P NMR spectroscopy, demonstrating a living cationic polymerization mechanism. The polymer chain lengths and molecular weights of the resulting substituted poly(organo)phosphazenes are further studied by 1H NMR spectroscopy and size exclusion chromatography. This strategy facilitates the preparation of polyphosphazenes with controlled molecular weights and specific functional groups at the α-chain end. Such well-defined, mono-end-functionalized polymers have great potential use in bioconjugation, surface modification, and as building blocks for complex macromolecular constructs. PMID:24700544

  11. Phosphine oxide type bipolar host material for high quantum efficiency in thermally activated delayed fluorescent device.

    PubMed

    Kim, Bo Seong; Lee, Jun Yeob

    2014-06-11

    Highly efficient thermally activated delayed fluorescence devices were developed using a bipolar host material, 2,7-bis(diphenylphosphoryl)-9-phenyl-9H-carbazole (PPO27), derived from carbazole and diphenylphosphine oxide. The PPO27 host was effective for good charge balance and energy transfer from the PPO27 host to thermally activated delayed fluorescence dopant. The PPO27 device doped with (4s,6s)-2,4,5,6-tetra(9H-carbazol-9-yl)isophthalonitrile dopant could realize a high quantum efficiency of 24.2%. PMID:24773083

  12. From Mesomorphic Phosphine Oxide to Clustomesogens Containing Molybdenum and Tungsten Octahedral Cluster Cores.

    PubMed

    Cîrcu, Viorel; Molard, Yann; Amela-Cortes, Maria; Bentaleb, Ahmed; Barois, Philippe; Dorcet, Vincent; Cordier, Stéphane

    2015-09-01

    New clustomesogens (i.e., metal atom clusters containing liquid crystalline (LC) materials) have been obtained by grafting neutral cyanobiphenyl (CB)- or cholesteryl-containing tailor-made dendritic mesomorphic triphenylphosphine oxide ligands on luminescent (M6 Cl(i) 8 )(4+) octahedral cluster cores (M=Mo, W). The LC properties were studied by a combination of polarizing optical microscopy (POM), differential scanning calorimetry (DSC), and X-ray powder diffraction analyses. While the organic ligands showed various mesophase types ranging from nematic, SmA columnar (SmACol ), SmA, and SmC phases, it turned out that the corresponding clustomesogens formed layered phases (SmA) over a wide range of temperatures that depend on the nature and density of mesogenic groups employed. Intrinsic luminescence properties of the cluster precursors are preserved over the entire range of LC phase existence. PMID:26211657

  13. Investigation of technetium complexes containing bidentate arsine and phosphine ligands: some applications to nuclear medicine

    SciTech Connect

    Glavan, K.A.

    1982-01-01

    New and previously reported di-, ter-, and penta-valent technetium complexes having the formulae (TcD/sub 2/X/sub 2/)Y, (TcD/sub 2/X/sub 2/), (TcD/sub 2/Cl/sub 4/)Y, and (TcD/sub 2/O/sub 2/)TcO/sub 4/, where D is o-phenylenebis(dimethylarsine) (diars), 1,2-bis(diphenylarsino)ethane (dae), or 1,2-bis(dimethylphosphino)ethane (dmpe), X is F, Cl, Br, or I, and Y is F/sup -/, Cl/sup -/, Br/sup -/, I/sub 3//sup -/, ClO/sub 4//sup -/, PF/sub 6//sup -/, or CF/sub 3/SO/sub 3//sup -/, have been synthesized. The complexes were characterized by elemental analysis, optical and vibrational spectroscopy, magnetic susceptibility, and single-crystal X-ray analysis. The chemical and spectral data for the six-coordinate halo complexes are consistent with a trans octahedral coordination geometry, being typical for (MD/sub 2/X/sub 2/)/sup +,0/ complexes.

  14. Solar cells made by laser-induced diffusion directly from phosphine gas

    SciTech Connect

    Turner, G.B.; Tarrant, D.; Pollock, G.; Pressley, R.; Press, R.

    1981-12-15

    A new method for making p-n junctions based on immersion in a transparent dopant gas followed by irradiation with a pulsed laser is presented. An alexandrite laser was used, operating at 0.73 ..mu..m where photolysis of the dopant gas PH/sub 3/ does not occur. Multiple pulses of 2.2--2.7 J/cm/sup 2/ were used to make Si solar cells with total area efficiencies up to 8.6% without benefit of antireflection coatings.

  15. Borane-protected phosphines are redox-active radioprotective agents for endothelial cells

    PubMed Central

    Crowe, Megan E.; Lieven, Christopher J.; Thompson, Alex F.; Sheibani, Nader; Levin, Leonard A.

    2015-01-01

    Exposure to radiation can damage endothelial cells in the irradiated area via the production of reactive oxygen species. We synthesized phosphine–borane complexes that reduce disulfide bonds and had previously been shown to interfere with redox-mediated signaling of cell death. We hypothesized that this class of drugs could interfere with the downstream effects of oxidative stress after irradiation and rescue endothelial cells from radiation damage. Cultured bovine aortic endothelial cells were plated for clonogenic assay prior to exposure to varying doses of irradiation from a 137Cs irradiator and treated with various concentrations of bis(3-propionic acid methyl ester)phenylphosphine borane complex (PB1) at different time points. The clone-forming ability of the irradiated cells was assessed seven days after irradiation. We compared the radioprotective effects of PB1 with the aminothiol radioprotectant WR1065 and known superoxide scavengers. PB1 significantly protected bovine aortic endothelial cells from radiation damage, particularly when treated both before and after radiation. The radioprotection with 1 µM PB1 corresponded to a dose-reduction factor of 1.24. Radioprotection by PB1 was comparable to the aminothiol WR1065, but was significantly less toxic and required much lower concentrations of drug (1 µM vs. 4 mM, respectively). Superoxide scavengers were not radioprotective in this paradigm, indicating the mechanisms for both loss of clonogenicity and PB1 radioprotection are independent of superoxide signaling. These data demonstrate that PB1 is an effective redox-active radioprotectant for endothelial cells in vitro, and is radioprotective at a concentration approximately 4 orders of magnitude lower than the aminothiol WR1065 with less toxicity. PMID:26188467

  16. Bis-phosphine allene ligand: coordination chemistry and preliminary applications in catalysis.

    PubMed

    Vanitcha, Avassaya; Damelincourt, Cecilia; Gontard, Geoffrey; Vanthuyne, Nicolas; Mouriès-Mansuy, Virginie; Fensterbank, Louis

    2016-05-21

    A 1,3-bis-diphenylphosphine allene can give rise to new coordination complexes with palladium, platinum and gold metals. These complexes were fully characterized by NMR, HRMS and X-ray diffraction analysis. For gold(i), the corresponding dinuclear complex has been used in a series of diagnostic catalytic reactions and gave promising preliminary results in asymmetric catalysis. PMID:27104618

  17. A Phosphine-Coordinated Boron-Centered Gomberg-Type Radical.

    PubMed

    Rosenthal, Amos J; Devillard, Marc; Miqueu, Karinne; Bouhadir, Ghenwa; Bourissou, Didier

    2015-08-01

    The P-coordinated boryl radical [Ph2P(naphthyl)BMes]˙ (Mes=mesityl) was prepared by (electro)chemical reduction of the corresponding borenium salt or bromoborane. Electron paramagnetic resonance (EPR) analysis in solution and DFT calculations indicate large spin density on boron (60-70%) and strong P-B interactions (P→B σ donation and B→P negative hyperconjugation). The radical is persistent in solution and participates in a Gomberg-type dimerization process. The associated quinoid-type dimer has been characterized by single-crystal X-ray diffraction. PMID:26118986

  18. Bond cleavage reactions in oxygen and nitrogen heterocycles by a rhodium phosphine complex

    SciTech Connect

    Jones, W.D.; Dong, L.; Myers, A.W. )

    1995-02-01

    The reactions of (C[sub 5]Me[sub 5])Rh(PMe[sub 3])PhH with furan, 2,5-dimethylfuran, 2,3-dihydrofuran, dibenzofuran, pyrrole, 1-methylpyrrole, 2,5-dimethylpyrrole, 1,2,5-trimethylpyrrole, carbazole, 9-methylcarbazole, pyrrolidine, pyridine, 3,5-lutidine, 2,4,6-collidine, pyrazole, 3-methylpyrazole, and piperidine have been investigated. While the oxygen heterocycles give only C-H activation, the nitrogen heterocycles yield C-H and N-H insertion products. The chloro derivative (C[sub 5]Me[sub 5])Rh(PMe[sub 3])[2-(1-methylpyrrole)]Cl was found to crystallize in the monoclinic space group C2/c with a = 13.753 (6) A, b = 9.665 (5) A, c = 30.14 (2) A, [beta] = 99.77 (5)-[degree], Z = 8, and V = 3949 (4.1) A[sup 3] while (C[sub 5]Me[sub 5])Rh(PMe[sub 5])[2-(3,5-lutidine)]Cl was found to crystallize in the monoclinic space group P2[sub 1]/c with a = 14.976 (8) A, b = 8.613 (5) A, c = 17.12 (2) A, [beta] = 101.90 (6)[degree], Z = 4, and V = 2160 (5.2) A[sup 3]. 30 refs., 2 figs., 3 tabs.

  19. Solvent Control of Surface Plasmon-Mediated Chemical Deposition of Au Nanoparticles from Alkylgold Phosphine Complexes.

    PubMed

    Muhich, Christopher L; Qiu, Jingjing; Holder, Aaron M; Wu, Yung-Chien; Weimer, Alan W; Wei, Wei David; McElwee-White, Lisa; Musgrave, Charles B

    2015-06-24

    Bottom-up approaches to nanofabrication are of great interest because they can enable structural control while minimizing material waste and fabrication time. One new bottom-up nanofabrication method involves excitation of the surface plasmon resonance (SPR) of a Ag surface to drive deposition of sub-15 nm Au nanoparticles from MeAuPPh3. In this work we used density functional theory to investigate the role of the PPh3 ligands of the Au precursor and the effect of adsorbed solvent on the deposition process, and to elucidate the mechanism of Au nanoparticle deposition. In the absence of solvent, the calculated barrier to MeAuPPh3 dissociation on the bare surface is <20 kcal/mol, making it facile at room temperature. Once adsorbed on the surface, neighboring MeAu fragments undergo ethane elimination to produce Au adatoms that cluster into Au nanoparticles. However, if the sample is immersed in benzene, we predict that the monolayer of adsorbed solvent blocks the adsorption of MeAuPPh3 onto the Ag surface because the PPh3 ligand is large compared to the size of the exposed surface between adsorbed benzenes. Instead, the Au-P bond of MeAuPPh3 dissociates in solution (Ea = 38.5 kcal/mol) in the plasmon heated near-surface region followed by the adsorption of the MeAu fragment on Ag in the interstitial space of the benzene monolayer. The adsorbed benzene forces the Au precursor to react through the higher energy path of dissociation in solution rather than dissociatively adsorbing onto the bare surface. This requires a higher temperature if the reaction is to proceed at a reasonable rate and enables the control of deposition by the light induced SPR heating of the surface and nearby solution. PMID:26036274

  20. Solid Molecular Phosphine Catalysts for Formic Acid Decomposition in the Biorefinery.

    PubMed

    Hausoul, Peter J C; Broicher, Cornelia; Vegliante, Roberta; Göb, Christian; Palkovits, Regina

    2016-04-25

    The co-production of formic acid during the conversion of cellulose to levulinic acid offers the possibility for on-site hydrogen production and reductive transformations. Phosphorus-based porous polymers loaded with Ru complexes exhibit high activity and selectivity in the base-free decomposition of formic acid to CO2 and H2 . A polymeric analogue of 1,2-bis(diphenylphosphino)ethane (DPPE) gave the best results in terms of performance and stability. Recycling tests revealed low levels of leaching and only a gradual decrease in the activity over seven runs. An applicability study revealed that these catalysts even facilitate selective removal of formic acid from crude product mixtures arising from the synthesis of levulinic acid. PMID:27043017

  1. Crystal structure of tert-butyl­diphenyl­phosphine oxide

    PubMed Central

    Agbeworvi, George; Assefa, Zerihun; Sykora, Richard E.; Taylor, Jared D.

    2015-01-01

    In the structure of the title triorganophosphine oxide, C16H19OP, the P—O bond is 1.490 (1) Å. The P atom has a distorted tetrahedral geometry. The O atom inter­acts with both phenyl groups of a neighboring mol­ecule [C⋯O = 2.930 (3) and 2.928 (4) Å]. The C—O interaction directs an extended supramolecular arrangement along the a-axis. PMID:26090188

  2. Phosphinogold(I) Dithiocarbamate Complexes: Effect of the Nature of Phosphine Ligand on Anticancer Properties

    PubMed Central

    2015-01-01

    The reactions of potassium salts of the dithiocarbamates L {where L = pyrazolyldithiocarbamate (L1), 3,5-dimethylpyrazolyldithiocarbamate (L2), or indazolyldithiocarbamate (L3)} with the gold precursors [AuCl(PPh3)], [Au2Cl2(dppe)], [Au2Cl2(dppp)], or [Au2Cl2(dpph)] lead to the new gold(I) complexes [AuL(PPh3)] (1–3), [Au2L2(dppe)] (4–6), [(Au2L2)(dppp)] (7–9), and [Au2(L)2(dpph)] (10–12) {where dppe = 1,2-bis(diphenylphosphino)ethane, dppp = 1,3-bis(diphenylphosphino)propane, and dpph = 1,6-bis(diphenylphosphino)hexane}. These gold compounds were characterized by a combination of NMR and infrared spectroscopy, microanalysis, and mass spectrometry; and in selected cases by single-crystal X-ray crystallography. Compounds 4–6, which have dppe ligands, are unstable in solution for prolonged periods, with 4 readily transforming to the Au18 cluster [Au18S8(dppe)6]Cl2 (4a) in dichloromethane. Compounds 1–3 and 7–12 are all active against human cervical epithelioid carcinoma (HeLa) cells, but the most active compounds are 10 and 11, with IC50 values of 0.51 μM and 0.14 μM, respectively. Compounds 10 and 11 are more selective toward HeLa cells than they are toward normal cells, with selectivities of 25.0 and 70.5, respectively. Further tests, utilizing the 60-cell-line Developmental Therapeutics Program at the National Cancer Institute (U.S.A.), showed 10 and 11 to be active against nine other types of cancers. PMID:24476103

  3. Highly selective Markovnikov hydroboration of alkyl-substituted terminal alkenes with a phosphine-copper(i) catalyst.

    PubMed

    Iwamoto, Hiroaki; Kubota, Koji; Ito, Hajime

    2016-05-21

    A new method has been developed for the Markovnikov hydroboration of alkyl-substituted terminal alkenes. Notably, the use of a bulky bisphosphine-copper(i) catalyst system resulted in high regioselectivity to afford secondary alkylboronates from the corresponding terminal alkenes (branch/linear = 92 : 8-97 : 3). This method also exhibited good functional group compatibility. PMID:26975671

  4. Insight into the electronic effect of phosphine ligand on Rh catalyzed CO2 hydrogenation by investigating the reaction mechanism.

    PubMed

    Ni, Shao-Fei; Dang, Li

    2016-02-01

    Improving the catalytic efficiency of CO2 hydrogenation is a big challenge in catalysed CO2 recycling and H2 conservation. The detailed mechanism of [Rh(PCH2X(R)CH2P)2](+) (X(R) = CH2, N-CH3, CF2) catalyzed CO2 hydrogenation is studied to obtain insights into the electronic effect of the substituents at diphosphine ligand on the catalytic efficiency. The most favorable reaction mechanism is found to be composed of three steps: (1) oxidative addition of dihydrogen onto the Rh center of the catalyst; (2) the first hydride abstraction by base from the Rh dihydride complexes; (3) the second hydride transfer from the Rh hydride complexes to CO2. It was found that the transition state for the first hydride abstraction from the Rh dihydride complex is the TOF-determining transition state (TDTS) in the most favorable mechanism. The energetic span (δE) of the cycle is suggested related to the thermodynamic hydricity of the Rh dihydride complex. Model catalyst [Rh(PCH2CF2CH2P)2](+) with a strong σ electron withdrawing group on the diphosphine ligand provides higher hydricity in the Rh dihydride complex and lower activation energy when compared with the other two catalysts. Our study shows that it is the σ electron withdrawing ability rather than the electron donating ability that enhances the catalytic efficiency in catalyzed CO2 hydrogenation. This finding will benefit ligand design in transition metal catalysts and lead to more efficient methods for CO2 transformation. PMID:26804824

  5. P,P-Bis[4-(dimethyl-amino)-phen-yl]-N,N-bis-(propan-2-yl)phosphinic amide.

    PubMed

    Evans, Stephen J; Renison, C Alicia; Williams, D Bradley G; Muller, Alfred

    2013-02-01

    The mol-ecular structure of the title compound, C(22)H(34)N(3)OP, adopts a distorted tetra-hedral geometry at the P atom, with the most noticeable distortion being for the O-P-N angle [117.53 (10)°]. An effective cone angle of 187° was calculated for the compound. In the crystal, weak C-H⋯O inter-actions create infinite chains along [100], whereas C-H⋯π inter-actions propagating in [001] generate a herringbone motif. PMID:23424479

  6. Nature of hydrogen interactions with Ni(II) complexes containing cyclic phosphine ligands with pendant nitrogen bases

    PubMed Central

    Wilson, Aaron D.; Shoemaker, R. K.; Miedaner, A.; Muckerman, J. T.; DuBois, Daniel L.; DuBois, M. Rakowski

    2007-01-01

    Studies of the role of proton relays in molecular catalysts for the electrocatalytic production and oxidation of H2 have been carried out. The electrochemical production of hydrogen from protonated DMF solutions catalyzed by [Ni(P2PhN2Ph)2(CH3CN)](BF4)2, 3a (where P2PhN2Ph is 1,3,5,7-tetraphenyl-1,5-diaza-3,7-diphosphacyclooctane), permits a limiting value of the H2 production rate to be determined. The turnover frequency of 350 s−1 establishes that the rate of H2 production for the mononuclear nickel catalyst 3a is comparable to those observed for Ni-Fe hydrogenase enzymes. In the electrochemical oxidation of hydrogen catalyzed by [Ni(P2CyN2Bz)2](BF4)2, 3b (where Cy is cyclohexyl and Bz is benzyl), the initial step is the reversible addition of hydrogen to 3b (Keq = 190 atm−1 at 25°C). The hydrogen addition product exists as three nearly isoenergetic isomers 4A–4C, which have been identified by a combination of one- and two-dimensional 1H, 31P, and 15N NMR spectroscopies as Ni(0) complexes with a protonated amine in each cyclic ligand. The nature of the isomers, together with calculations, suggests a mode of hydrogen activation that involves a symmetrical interaction of a nickel dihydrogen ligand with two amine bases in the diphosphine ligands. Single deprotonation of 4 by an external base results in a rearrangement to [HNi(P2CyN2Bz)2](BF4), 5, and this reaction is reversed by the addition of a proton to the nickel hydride complex. The small energy differences associated with significantly different distributions in electron density and protons within these molecules may contribute to their high catalytic activity. PMID:17360385

  7. Synthesis and evaluation of glycopolymeric decorated gold nanoparticles functionalized with gold-triphenyl phosphine as anti-cancer agents.

    PubMed

    Adokoh, Christian K; Quan, Stephen; Hitt, Mary; Darkwa, James; Kumar, Piyush; Narain, Ravin

    2014-10-13

    In this study, statistical glyco-dithiocarbamate (DTC) copolymers were synthesized by reversible addition-fragmentation chain transfer polymerization (RAFT) and subsequently used to prepare glyconanoparticles and conjugated glyconanoparticles with the anticancer drug, gold(I) triphenylphosphine. These glyconanoparticles and the corresponding conjugates were then tested for their in vitro cytotoxicity in both normal and cancer cell lines using Neutral Red assay. The glyconanoparticles and their Au(I)PPh3 conjugates were all active against MCF7 and HepG2 cells, but galactose-functionalized glyconanoparticles {P(GMA-EDAdtc(AuPPh3)-st-LAEMA)AuNP} were found to be the most cytotoxic to HepG2 cells (IC50 ∼ 4.13 ± 0.73 μg/mL). The p(GMA-EDAdtc(AuPPh3)-st-LAEMA)AuNP was found to be a 4-fold more potent antitumor agent in HepG2 cells, and the overexpressed asialoglycoprotein (ASGPR) receptors revealed to play an important role in the cytotoxicity, presumably by the enhanced uptake. In addition, the glyconanoparticles Au(I) conjugates are found to be significantly more toxic as compared to the standard chemotherapeutic reagents such as cisplatin and cytarabine. PMID:25162942

  8. Interaction of hydrated protons with octyl-phenyl-N,N-diisobutylcarbamoylmethyl phosphine oxide (CMPO): NMR and theoretical study.

    PubMed

    Kříž, Jaroslav; Dybal, Jiří; Makrlík, Emanuel; Vaňura, Petr

    2011-10-01

    Interaction of octyl-phenyl-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO, the 'classical' rare metal extraction agent) with fully ionized hydrated protons (HP) was studied in acetonitrile-d(3) using (1)H, (13)C, (31)P NMR, PFG NMR and magnetic relaxation. The experimental results were confronted with high-precision ab initio DFT calculations. Relative chemical shifts of NMR signals of CMPO (0.01 mol/L) under the presence of HP in the molar ratio β = 0-2.0 mol/mol show binding between CMPO and HP. Self-diffusion measurements using (1)H PFG NMR demonstrate that larger complexes with higher content of CMPO are generally formed at β < 0.75. Analyzing the collective dependence of (13)C and (31)P NMR chemical shifts on β by the use of program LETAGROP, we obtained very good fitting for the assumed coexistence of two complexes (CMPO)(2)·HP (C(2)) and CMPO.HP (C(1)). The logarithms of the respective stabilization constants log K(i) were found to be 7.518 (C(2)) and 4.581 (C(1)). The system dynamics was studied by measuring the transverse (1)H NMR relaxation using CPMG sequence with varying delays t(p) between the π pulses in the mixtures with β = 0.4-0.8. The following exchange correlation times were obtained: τ(10) = 2.35 × 10(-5), τ(20) = 0.82 × 10(-4), τ(21) = 0.45 × 10(-3) s. The DFT calculations support the conclusion that the complexes C(1) and C(2) are the main species in the mixtures of CMPO with HP. They also agree with the NMR and FTIR observation that the main site to which H(3) O(+) is bound is the P=O group, whereas the amide group does not form a strong bond with the ion when excess water molecules are present. PMID:21898583

  9. Extraction of actinides and fission products by octyl(phenyl)-N,N-diisobutylcarbamoylmethyl-phosphine oxide from nitric acid media.

    PubMed

    Mathur, J N; Murali, M S; Natarajan, P R; Badheka, L P; Banerji, A

    1992-05-01

    Extraction of promethium(III), uranium(VI), plutonium(IV), americium(III), zirconium(IV), ruthenium(III), iron(III) and palladium(II) has been carried out with a mixture of octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) and tributyl phosphate (TBP) in dodecane. The effects of nitric acid, TBP and CMPO concentrations on the extraction of these metal ions have been studied. The nature of the species of the above metal ions extracted into the organic phase has been suggested. PMID:18965406

  10. Coinage metal complexes with bridging hybrid phosphine-NHC ligands: synthesis of di- and tetra-nuclear complexes.

    PubMed

    Simler, Thomas; Braunstein, Pierre; Danopoulos, Andreas A

    2016-03-15

    A series of P-NHC-type hybrid ligands containing both PR2 and N-heterocyclic carbene (NHC) donors on meta-bis-substituted phenylene backbones, , and (R = Cy, tBu, Ph, respectively), was accessed through a modular synthesis from a common precursor, and their coordination chemistry with coinage metals was explored and compared. Metallation of ·n(HBr) (n = 1, 2) with Ag2O gave the pseudo-cubane [Ag4Br4()2], isostructural to [Ag4Br4()2] (R = Cy, tBu) (T. Simler, P. Braunstein and A. A. Danopoulos, Angew. Chem., Int. Ed., 2015, 54, 13691), whereas metallation of ·HBF4 (R = Ph, tBu) led to the dinuclear complexes [Ag2()2](BF4)2 which, in the solid state, feature heteroleptic Ag centres and a 'head-to-tail' (HT) arrangement of the bridging ligands. In solution, interconversion with the homoleptic 'head-to-head' (HH) isomers is facilitated by ligand fluxionality. 'Head-to-tail' [Cu2Br2()2] (R = Cy, tBu) dinuclear complexes were obtained from ·HBr and [Cu5(Mes)5], Mes = 2,4,6-trimethylphenyl, which also feature bridging ligands and heteroleptic Cu centres. Although the various ligands led to structurally analogous complexes for R = Cy, tBu and Ph, the rates of dynamic processes occurring in solution are dependent on R, with faster rates for R = Ph. Transmetallation of both NHC and P donor groups from [Ag4Br4()2] to Au(I) by reaction with [AuCl(THT)] (THT = tetrahydrothiophene) led to transfer and to the dinuclear complex [Au2Cl2] with one ligand bridging the two Au centres. Except for the silver pseudo-cubanes, all other complexes do not exhibit metallophilic interactions. PMID:26886084

  11. Line positions and intensities of the phosphine (PH3) Pentad near 4.5 μm

    SciTech Connect

    Devi, V. Malathy; Kleiner, Isabelle; Sams, Robert L.; Brown, Linda R.; Benner, D. C.; Fletcher, Leigh N.

    2014-04-01

    In order to improve the spectroscopic database for remote sensing of the giant planets, line positions and intensities are determined for the five bands (2ν2, ν2 + ν4, 2ν4, ν1 and ν3) that comprise the Pentad of PH3 between 1950 and 2450 cm−1. Knowledge of PH3 spectral line parameters in this region is important for the exploration of dynamics and chemistry on Saturn, (using existing Cassini/VIMS observations) and future near-IR data of Jupiter from Juno and ESA’s Jupiter Icy Moons Explorer (JUICE). For this study, spectra of pure PH3 from two Fourier transform spectrometers were obtained: (a) five high-resolution (0.00223 cm−1), high signal-to-noise (∼1800) spectra recorded at room temperature (298.2 K) with the Bruker IFS 125HR Fourier transform spectrometer (FTS) at the Pacific Northwest National Laboratory (PNNL), Richland, Washington and (b) four high-resolution (at 0.0115 cm−1 resolution), high signal-to-noise (∼700) spectra recorded at room temperature in the region 1800–5200 cm−1 using the McMath-Pierce Fourier transform spectrometer located at the National Solar Observatory (NSO) on Kitt Peak. Individual line parameters above 2150 cm−1 were retrieved by simultaneous multispectrum fittings of all five Bruker spectra, while retrievals with the four Kitt Peak spectra were done in the 1938–2168 cm−1 range spectrum by spectrum and averaged. In all, positions and intensities were obtained for more than 4400 lines. These included 53 A+A− split pairs of transitions (arising due to vibration–rotation interactions (Coriolis-type interaction) between the ν3 and ν1 fundamental bands) for K″ = 3, 6, and 9. Over 3400 positions and 1750 intensities of these lines were ultimately identified as relatively unblended and modeled up to J = 14 and K = 12 with rms values of 0.00133 cm−1 and 7.7%, respectively. The PH3 line parameters (observed positions and measured intensities with known quantum assignments) and Hamiltonian constants are reported. Comparisons with other recent studies are discussed.

  12. (2-{[2-(diphenyl­phosphino)phen­yl]thio}­phen­yl)diphenyl­phosphine sulfide

    PubMed Central

    Alvarez-Larena, Angel; Martinez-Cuevas, Francisco J.; Flor, Teresa; Real, Juli

    2012-01-01

    In the title compound, C36H28P2S2, the dihedral angle between the central benzene rings is 66.95 (13)°. In the crystal, molecules are linked via Car—H⋯π and π–π inter­actions [shortest centroid–centroid distance between benzene rings = 3.897 (2) Å]. PMID:23284423

  13. Taking TiF4 complexes to extremes--the first examples with phosphine co-ligands.

    PubMed

    Jura, Marek; Levason, William; Petts, Edmund; Reid, Gillian; Webster, Michael; Zhang, Wenjian

    2010-11-14

    The first soft donor adducts of TiF(4), [TiF(4)(diphosphine)] (diphosphine = o-C(6)H(4)(PMe(2))(2), R(2)P(CH(2))(2)PR(2), R = Me or Et) have been prepared from [TiF(4)(MeCN)(2)] and the diphosphines in rigorously anhydrous CH(2)Cl(2), as extremely moisture sensitive yellow solids, and characterised by multinuclear NMR ((1)H, (31)P, (19)F), IR and UV/vis spectroscopy. The crystal structure of [TiF(4){Et(2)P(CH(2))(2)PEt(2)}] has been determined and shows a distorted six-coordinate geometry with disparate Ti-F(transF) and Ti-F(transP) distances and long Ti-P bonds. Weaker soft donor ligands including Ph(3)P, Ph(2)P(CH(2))(2)PPh(2), o-C(6)H(4)(PPh(2))(2), Ph(2)As(CH(2))(2)AsPh(2), o-C(6)H(4)(AsMe(2))(2) and (i)PrS(CH(2))(2)S(i)Pr do not form stable complexes with TiF(4), although surprisingly, fluorotitanate(IV) salts of the previously unknown doubly protonated ligand cations [LH(2)][Ti(4)F(18)] (L = o-C(6)H(4)(PPh(2))(2), o-C(6)H(4)(AsMe(2))(2) and (i)PrS(CH(2))(2)S(i)Pr) are formed in some cases as minor by-products. The structure of [o-C(6)H(4)(PPh(2)H)(2)][Ti(4)F(18)] shows the first authenticated example of a diprotonated o-phenylene-diphosphine. The synthesis and full spectroscopic characterisation are reported for a range of TiF(4) adducts with hard N- or O-donor ligands for comparison purposes, along with crystal structures of [TiF(4)(thf)(2)], [TiF(4)(Ph(3)EO)(2)]·2CH(2)Cl(2) (E = P or As), and [TiF(4)(bipy)]. PMID:20882256

  14. High-efficiency turquoise-blue electrophosphorescence from a Pt(II)-pyridyltriazolate complex in a phosphine oxide host

    NASA Astrophysics Data System (ADS)

    Bhansali, Unnat S.; Polikarpov, Evgueni; Swensen, James S.; Chen, Wei-Hsuan; Jia, Huiping; Gaspar, Daniel J.; Gnade, Bruce E.; Padmaperuma, Asanga B.; Omary, Mohammad A.

    2009-12-01

    We demonstrate high-efficiency turquoise-blue electrophosphorescence from bis[3,5-bis(2-pyridyl)-1,2,4-triazolato]platinum(II) [Pt(ptp)2] doped in 4-(diphenylphosphoryl)-N ,N-diphenylaniline(HM-A1). Organic light-emitting diodes (OLEDs) with 5% Pt(ptp)2:HM-A1 attain peak power efficiency of 61.2 lm/W, versus 40.8 lm/W for analogous devices employing the standard turquoise-blue phosphor bis[(4,6-difluorophenyl)-pyridinato-N,C2'](picolinato)iridium(III) (FIrpic). Devices with x% Pt(ptp)2:HM-A1 exhibit blue emission maxima (λmax˜480 nm) with monotonic increase in excimer/monomer intensity ratio at higher doping levels within 1%-10%, causing color shift toward green and less charge balance. This work represents a significant step toward optimizing future white OLEDs from the same phosphor via combination of low-doped and higher-doped or neat films.

  15. New Ru complexes containing the N-tridentate bpea and phosphine ligands: consequences of meridional vs facial geometry.

    PubMed

    Mola, Joaquim; Rodrguez, Montserrat; Romero, Isabel; Llobet, Antoni; Parella, Teodor; Poater, Albert; Duran, Miquel; Sol, Miquel; Benet-Buchholz, Jordi

    2006-12-25

    The synthesis and isolation of the complex cis,fac-[RuIICl2(bpea)(PPh3)][3; bpea = N,N-bis(2-pyridylmethyl)ethylamine] and three geometrical isomers of the complex [RuIICl(bpea)(dppe)](BF4) [4; dppe = (1,2-diphenylphosphino)ethane], trans,fac (4a), cis,fac (4b), and mer(down) (4c), have been described (see Chart 1 for a drawing of their structures). These complexes have been characterized through analytical, spectroscopic (IR, UV/vis, and 1D and 2D NMR), and electrochemical (cyclic voltammetry) techniques. In addition, complexes 3, 4a, and 4b have been further characterized in the solid state through monocrystal X-ray diffraction analysis. The molecular and electronic structures of isomers 4a, 4b, 4c, and 4d (the mer(up) isomer) have also been studied by means of density functional theory (DFT) calculations. Furthermore, their low-energy electronic transitions have been simulated using time-dependent DFT approaches, which have allowed unraveling of their metal-to-ligand charge-transfer nature. Complexes 3 and 4a-c are capable of catalyzing H-transfer types of reactions between alcohols and aromatic ketones such as acetophenone and 2,2-dimethylpropiophenone (DP). A strong influence of the facial versus meridional geometry in the bpea ligand coordination mode is observed for these catalytic reactions, with the meridional isomer being much more active than the facial one. The meridional isomer is even capable of carrying out the H-transfer reaction of bulky substrates such as DP at room temperature. PMID:17173407

  16. Mass spectrometric studies of phosphine pyrolysis and OMVPE growth of InP. [organometallic vapor phase epitaxy

    NASA Technical Reports Server (NTRS)

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

    1987-01-01

    The mechanism of PH3 decomposition was studied by using D2 as a carrier gas and analyzing the reaction products with a mass spectrometer. The effects of InP and silica surfaces were investigated. The only gaseous product below 600 C is H2. Since any gas-phase H atoms would produce HD, the reaction occurs entirely on the surface. The slow step is the unimolecular removal of the first hydrogen atom, with an activation energy of 36.0 kcal/mole on InP surfaces. The reaction on InP is first-order for PH3 concentrations as high as 15 percent, so the surface is not saturated at those conditions. When trimethylindium (TMIn) is added to the gas mixture, the mechanism changes dramatically, probably proceeding via an unstable intermediate adduct of TMIn and PH3 which eliminates CH4 upon formation. This concerted reaction lowers the pyrolysis temperatures of both PH3 and TMIn.

  17. Nonlinear optical absorption and fluorescence of phosphine-substituted bithiophenes in the violet-blue spectral region

    NASA Astrophysics Data System (ADS)

    Wang, Jianwei; Zhao, Qun; Lawson, Christopher M.; Gray, Gary M.

    2011-06-01

    The nonlinear optical absorptions of two 5,5‧-bis(diphenylphosphino)-2,2‧-bithiophene derivatives, Ph2(X)P(C4H2S)2P(X)Ph2 (X = O, 1; S, 2), have been investigated by direct transmission measurement with both picosecond and nanosecond laser pulses from 420 nm to 480 nm. Saturated dichloromethane solutions of 1 and 2 exhibit strong nonlinear optical absorptions in this violet-blue spectral region with that of 2 being stronger at all wavelengths. In the picosecond regime, at 420 nm, the transmittance rapidly falls to 50% when the incident fluence is 0.22 J/cm2 for 1 and 0.11 J/cm2 for 2. Two-photon absorption appears to be the primary mechanism for this nonlinear absorption. The two-photon absorption coefficients β for 1 (2.1 cm/GW) and 2 (4.4 cm/GM) were obtained by fitting the measurement of transmittance as the function of incident beam intensity at 420 nm. These β values are comparable with some of the best results obtained for organic materials in the green, red and infrared spectral region. Both compounds also show fluorescence with an emission peak at 390 nm for 1 and 400 nm for 2. The fluorescence of 1 is considerably stronger than is that of 2. The combination of the wide band gap and strong fluorescence emission of 1 makes it a promising candidate as a host material for blue organic light emitting diodes.

  18. Tri(1-adamantyl)phosphine: Expanding the Boundary of Electron-Releasing Character Available to Organophosphorus Compounds.

    PubMed

    Chen, Liye; Ren, Peng; Carrow, Brad P

    2016-05-25

    We report here the remarkable properties of PAd3, a crystalline air-stable solid accessible through a scalable SN1 reaction. Spectroscopic data reveal that PAd3, benefiting from the polarizability inherent to large hydrocarbyl groups, exhibits unexpected electron releasing character that exceeds other alkylphosphines and falls within a range dominated by N-heterocyclic carbenes. Dramatic effects in catalysis are also enabled by PAd3 during Suzuki-Miyaura cross-coupling of chloro(hetero)arenes (40 examples) at low Pd loading, including the late-stage functionalization of commercial drugs. Exceptional space-time yields are demonstrated for the syntheses of industrial precursors to valsartan and boscalid from chloroarenes with ∼2 × 10(4) turnovers in 10 min. PMID:27164163

  19. Coordination Chemistry Inside Polymeric Nanoreactors: Interparticle Metal Exchange and Ionic Compound Vectorization in Phosphine-Functionalized Amphiphilic Polymer Latexes.

    PubMed

    Chen, Si; Gayet, Florence; Manoury, Eric; Joumaa, Ahmad; Lansalot, Muriel; D'Agosto, Franck; Poli, Rinaldo

    2016-04-25

    Stable latexes of hierarchically organized core-cross-linked polymer micelles that are functionalized at the core with triphenylphosphine (TPP@CCM) have been investigated by NMR spectroscopic analysis at both natural (ca. pH 5) and strongly basic (pH 13.6) pH values after core swelling with toluene. The core-shell interface structuring forces part of the hydrophilic poly(ethylene oxide) (PEO) chains to reside inside the hydrophobic core at both pH values. Loading the particle cores with [Rh(acac)(CO)2 ] (acac=acetylacetonate) at various Rh/P ratios yielded polymer-supported [Rh(acac)(CO)(TPP)] (TPP=triphenylphosphine). The particle-to-particle rhodium migration is very fast at natural pH, but slows down dramatically at high pH, whereas the size distribution of the nanoreactors remains unchanged. The slow migration at pH 13.6 leads to the generation of polymer-anchored [Rh(OH)(CO)(TPP)2 ], which is also generated immediately upon the addition of NaOH to the particles with a [Rh(acac)(CO)] loading of 50 %. Similarly, treatment of the same particles with NaCl yielded polymer-anchored [RhCl(CO)(TPP)2 ]. Interparticle coupling occurs during these rapid processes. These experiments prove that the major contribution to metal migration is direct core-core contact. The slow migration at the high pH value, however, must result from a pathway that does not involve core-core contact. The facile penetration of the polymer cores by NaOH and NaCl results from the presence of shell-linked poly(ethylene oxide) methyl ether functions both outside and inside the polymer core-shell interface. PMID:27001452

  20. Photochromic and electrochromic properties of oxo-centred triruthenium compounds with a dithienylethene bis(phosphine) ligand.

    PubMed

    Dai, Feng-Rong; Li, Bin; Shi, Lin-Xi; Zhang, Li-Yi; Chen, Zhong-Ning

    2009-12-14

    The reaction of 1,2-bis(5-(diphenylphosphino)-2-methylthien-3-yl) cyclopentene (PPh(2)-DTE-PPh(2)) with the triruthenium cluster precursor [Ru(3)O(OAc)(6)(py)(2)(CH(3)OH)](PF(6)) (1) gave monomeric or dimeric derivatives [Ru(3)O(OAc)(6)(py)(2){PPh(2)-DTE-PPh(2)}](PF(6)) ([2]PF(6)) and [{Ru(3)O(OAc)(6)(py)(2)}(2){mu-PPh(2)-DTE-PPh(2)}](PF(6))(2) ([3]PF(6)). Reduction of [2](+) and [3](2+) afforded one- or two-electron-reduced neutral products Ru(3)O(OAc)(6)(py)(2){PPh(2)-DTE-PPh(2)} (2) and {Ru(3)O(OAc)(6)(py)(2)}(2){mu-PPh(2)-DTE-PPh(2)} ()3, respectively. These triruthenium complexes show remarkable photochromism through photochemical ring-closing (UV light irradiation) and ring-opening (Vis light irradiation) processes as well as electrochromic properties through oxidation/reduction in the triruthenium cluster. Both the photochromic and electrochromic properties of 2 and 3 are highly reversible. PMID:19921059

  1. Size-dependent stability toward dissociation and ligand binding energies of phosphine-ligated gold cluster ions

    SciTech Connect

    Johnson, Grant E.; Priest, Thomas A.; Laskin, Julia

    2014-01-01

    The stability of sub-nanometer size gold clusters ligated with organic molecules is of paramount importance to the scalable synthesis of monodisperse size-selected metal clusters with highly tunable chemical and physical properties. For the first time, a Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR-MS) equipped with surface induced dissociation (SID) has been employed to investigate the time and collision energy resolved fragmentation behavior of cationic doubly charged gold clusters containing 7-9 gold atoms and 6-7 triphenylphosphine (TPP) ligands prepared by reduction synthesis in solution. The TPP ligated gold clusters are demonstrated to fragment through three primary dissociation pathways: (1) Loss of a neutral TPP ligand from the precursor gold cluster, (2) asymmetric fission and (3) symmetric fission and charge separation of the gold core resulting in formation of complementary pairs of singly charged fragment ions. Threshold energies and activation entropies of these fragmentation pathways have been determined employing Rice-Ramsperger-Kassel-Marcus (RRKM) modeling of the experimental SID data. It is demonstrated that the doubly charged cluster ion containing eight gold atoms and six TPP ligands, (8,6)2+, exhibits exceptional stability compared to the other cationic gold clusters examined in this study due to its large ligand binding energy of 1.76 eV. Our findings demonstrate the dramatic effect of the size and extent of ligation on the gas-phase stability and preferred fragmentation pathways of small TPP-ligated gold clusters.

  2. Palladium(II)-Catalyzed Synthesis of Sulfinates from Boronic Acids and DABSO: A Redox-Neutral, Phosphine-Free Transformation.

    PubMed

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

    2016-01-11

    A redox-neutral palladium(II)-catalyzed conversion of aryl, heteroaryl, and alkenyl boronic acids into sulfinate intermediates, and onwards to sulfones and sulfonamides, has been realized. A simple Pd(OAc)2 catalyst, in combination with the sulfur dioxide surrogate 1,4-diazabicyclo[2.2.2]octane bis(sulfur dioxide) (DABSO), is sufficient to achieve rapid and high-yielding conversion of the boronic acids into the corresponding sulfinates. Addition of C- or N-based electrophiles then allows conversion into sulfones and sulfonamides, respectively, in a one-pot, two-step process. PMID:26596861

  3. Selective extraction of metal ions with polymeric extractants by ion exchange/redox

    DOEpatents

    Alexandratos, Spiro D.

    1987-01-01

    The specification discloses a method for the extraction of metal ions having a reduction potential of above about +0.3 from an aqueous solution. The method includes contacting the aqueous solution with a polymeric extractant having primary phosphinic acid groups, secondary phosphine oxide groups, or both phosphinic acid and phosphine oxide groups.

  4. A radioimmunoassay for SQ 27,519, the active phosphinic acid-carboxylic diacid of the prodrug fosinopril in human serum

    SciTech Connect

    Tu, J.I.; Brennan, J.; Stouffer, B.; Eckelman, W.C. )

    1990-07-01

    Fosinopril (SQ 28,555) is a member of a new chemical class of angiotensin converting enzyme inhibitors being developed by The Squibb Institute for Medical Research. During or following absorption, fosinopril, a prodrug, is hydrolyzed pharmacologically to the active diacid, SQ 27,519. A specific radioimmunoassay (RIA) for the measurement of SQ 27,519 in human serum has been developed. The assay utilizes a specific SQ 27,519 antibody, 125I-iodohistamine-SQ 27,519 radiolabel, and human serum standards. Satisfactory zero binding and assay sensitivity are achieved after a 2-h incubation at room temperature. Separation of the antibody-bound and free radiolabeled antigens is achieved by using polyethylene glycol-goat anti-rabbit gamma globulin separant. Recovery efficiencies ranged from 97.2 to 109.4%. The assay exhibited little or no cross-reactivity with captopril. Cross-reactivities for prodrug (SQ 28,555) and phenolic SQ 27,519 were 5 and 9%, respectively. Intra-assay variability (3.3-5.6%) and interassay variability (7.1-6.6%) were observed. Linear regression analysis indicates that RIA and (14C) thin-layer radiochromatography (TLRC) methods gave a highly significant correlation (RIA = 1.0 (14C)TLRC + 0.17, r = 0.991). Pharmacokinetic profiles of patient sera containing SQ 27,519 obtained by RIA and (14C)TLRC are identical. The RIA has been used routinely in support of the bioavailability and pharmacokinetic studies of fosinopril in humans.

  5. Titanocene-phosphine derivatives as precursors to cytotoxic heterometallic TiAu2 and TiM (M = Pd, Pt) compounds. Studies of their interactions with DNA.

    PubMed

    González-Pantoja, Jose F; Stern, Michael; Jarzecki, Andrzej A; Royo, Eva; Robles-Escajeda, Elisa; Varela-Ramírez, Armando; Aguilera, Renato J; Contel, María

    2011-11-01

    A series of tri- and bimetallic titanium-gold, titanium-palladium, and titanium-platinum derivatives of the general formulas [Ti{η(5)-C(5)H(4)(CH(2))(n)PPh(2)(AuCl)}(2)]·2THF [n = 0 (1); n = 2 (2); n = 3 (3)] and [TiCl(2){η(5)-C(5)H(4)κ-(CH(2))(n)PPh(2)}(2)(MCl(2))]·2THF [M = Pd, n = 0 (4); n = 2 (5); n = 3 (6) ; M = Pt, n = 0 (7); n = 2 (8); n = 3 (9)] have been synthesized and characterized by different spectroscopic techniques and mass spectrometry. The molecular structures of compounds 1-9 have been investigated by means of density functional theory calculations. The calculated IR spectra of the optimized structures fit well with the experimental IR data obtained for 1-9. The stability of the heterometallic compounds in deuterated solvents [CDCl(3), dimethyl sulfoxide (DMSO)-d(6), and mixtures 50:50 DMSO-d(6)/D(2)O and 1:99 DMSO-d(6)/D(2)O at acidic and neutral pH] has been evaluated by (31)P and (1)H NMR spectroscopy showing a higher stability for these compounds than for Cp(2)TiCl(2) or precursors [Ti{η(5)-C(5)H(4)(CH(2))(n)PPh(2)}(2)]. The new compounds display a lower acidity (1-2 units) than Cp(2)TiCl(2). The decomposition products have been identified over time. Complexes 1-9 have been tested as potential anticancer agents, and their cytotoxicity properties were evaluated in vitro against HeLa human cervical carcinoma and DU-145 human prostate cancer cells. TiAu(2) and TiPd compounds were highly cytotoxic for these two cell lines. The interactions of the compounds with calf thymus DNA have been evaluated by thermal denaturation (1-9) and by circular dichroism (1, 3, 4, and 7) spectroscopic methods. All of these complexes show a stronger interaction with DNA than that displayed by Cp(2)TiCl(2) at neutral pH. The data are consistent with electrostatic interactions with DNA for TiAu(2) compounds and for a covalent binding mode for TiM (M = Pd, Pt) complexes. PMID:21958150

  6. Scanning tunneling microscopy study of low temperature silicon epitaxy on hydrogen/silicon(001) and phosphine adsorption on silicon(111)-7x7

    NASA Astrophysics Data System (ADS)

    Ji, Jeong-Young

    A three-chamber ultra-high-vacuum (UHV) system with preparation, scanning tunneling microscopy (STM), and chemical vapor deposition (CVD) chambers was designed and built. Here, one can perform surface preparation, STM e-beam lithography, precursor gas dosing, ion sputtering, silicon epitaxy, and various measurements such as reflection high energy electron diffraction (RHEED), low energy electron diffraction (LEED), and Auger electron spectroscopy (AES). Processes performed in the ultra-clean preparation and gas-filled CVD chambers can be monitored by transferring the samples back to the STM chamber to take topographical images. Si deposition on H-terminated Si(001)-2x1 surfaces at temperatures 300--530 K was studied by scanning tunneling microscopy. Hydrogen apparently hinders Si adatom diffusion and enhances surface roughening. Post-growth annealing transfers the top layer atoms downward to fill in vacancies in the lower layer, restoring the crystallinity of the thin film. Hydrogen is shown to remain on the growth front up to at least 10 ML. Si deposition onto the H/Si(001)-3x1 surface at 530 K suggests that dihydride units further suppress Si adatom diffusion and increase surface roughness. PH3 adsorption on Si(111)-7x7 was studied for various exposures between 0.3--60 L at room temperature by means of the scanning-tunneling-microscopy (STM). PH3-, PH2-, H-reacted, and unreacted adatoms can be identified by analyzing STM images at different sample biases. Most of PH3 adsorbs dissociatively on the surface at initial exposure, generating H and PH2 adsorption sites, followed by molecular adsorption of PH3. Rest atoms are more reactive than the adatoms and PH 2-reacted rest atom sites are also observed in STM images. Statistical analysis shows that center adatoms are more reactive than corner adatoms and the saturation P coverage is ˜0.22 ML. Finally, 900 K annealing of a PH 3 dosed surface results in a disordered, partially P-covered surface and PH3 dosing at 900 K forms the same surface reconstruction as a P2-adsorbed surface at similar temperature.

  7. Low-temperature superstructure of [(N,N-diisobutyl­carbamo­yl)meth­yl]oct­yl(phen­yl)phosphine oxide (CMPO)

    PubMed Central

    Pojarová, Michaela; Fejfarová, Karla; Makrlík, Emanuel

    2011-01-01

    At 120 K, the title compound, C24H42NO2P, crystallizes in a unit cell with a doubled a parameter compared with the room-temperature structure. There are four mol­ecules in the asymmetric unit, one of which shows extensive disorder in a 0.588 (3):0.412 (3) ratio. In the crystal, numerous C—H⋯O inter­actions link the mol­ecules. PMID:22199779

  8. Phosphine-Free, Heterogeneous Palladium-Catalyzed Atom-Efficient Carbonylative Cross-Coupling of Triarylbismuths with Aryl Iodides: Synthesis of Biaryl Ketones.

    PubMed

    Hao, Wenyan; Liu, Haiyi; Yin, Lin; Cai, Mingzhong

    2016-05-20

    A novel and highly efficient heterogeneous palladium-catalyzed carbonylative cross-coupling of aryl iodides with triarylbismuths has been developed that proceeds smoothly at atmospheric CO pressure and provides a general and powerful tool for the preparation of various valuable biaryl ketones with high atom economy, good to excellent yield, and recyclability of the catalyst. The reaction is the first example of Pd-catalyzed carbonylative cross-coupling for the construction of biaryl ketones using triarylbismuths as substrates. PMID:27129099

  9. Synthesis, structure, and electrochemistry of di- and zerovalent nickel, palladium, and platinum monomers and dimers derived from an enantiopure (S,S)-tetra(tertiary phosphine).

    PubMed

    Kitto, Heather J; Rae, A David; Webster, Richard D; Willis, Anthony C; Wild, S Bruce

    2007-09-17

    The ligand (S,S)-1,1,4,7,10,10-hexaphenyl-1,4,7,10-tetraphosphadecane, (S,S)-tetraphos, reacts with hexa(aqua)nickel(II) chloride in the presence of trimethylsilyl triflate (TMSOTf) in dichloromethane to give the yellow square-planar complex [Ni{(R,R)-tetraphos}](OTf)2, which has been crystallographically characterized as the square-pyramidal, acetonitrile adduct [Ni(NCMe){(R,R)-tetraphos}]OTf. Cyclic voltammograms of the nickel(II) complex in dichloromethane and acetonitrile at 20 degrees C showed two reduction processes at negative potentials with oxidative (E(p)(ox)) and reductive (E(p)(red)) peak separations similar to those observed for ferrocene/ferrocenium under identical conditions, suggesting two one-electron steps. The cyclic voltammetric data for the divalent nickel complex in acetonitrile at temperatures below -20 degrees C were interpreted according to reversible coordination of acetonitrile to the nickel(I) and nickel(0) complexes. The divalent palladium and platinum complexes [M{(R,R)-tetraphos}](PF6)2 and [M2{(R,R)-tetraphos}2](OTf)4 have been prepared. The reduction potentials for the complexes [M{(R,R)-tetraphos}](PF6)2 increase in the order nickel(II) < palladium(II) < platinum(II). The reaction of (S,S)-tetraphos with bis(cycloocta-1,5-diene)nickel(0) in benzene affords orange [Ni{(R,R)-tetraphos}], which slowly rearranges into the thermodynamically more stable, yellow, double-stranded helicate [Ni2{(R,R)-tetraphos}2]; the crystal structures of both complexes have been determined. The reactions of (S,S)-tetraphos with [M(PPh3)4] in toluene (M = Pd) or benzene (M = Pt) furnish the double-stranded helicates [M2{(R,R)-tetraphos}2]; the palladium complex crystallizes from hot benzene as the 2-benzene solvate and was structurally characterized by X-ray crystallography. In each of the three zerovalent complexes, the coordinated (R,R)-tetraphos stereospecifically generates tetrahedral M(PP)2 stereocenters of M configuration. PMID:17696428

  10. Gold(I)-phosphine-N-heterocycles: biological activity and specific (ligand) interactions on the C-terminal HIVNCp7 zinc finger.

    PubMed

    Abbehausen, Camilla; Peterson, Erica J; de Paiva, Raphael E F; Corbi, Pedro P; Formiga, André L B; Qu, Yun; Farrell, Nicholas P

    2013-10-01

    The syntheses and the characterization by chemical analysis, (1)H and (31)P NMR spectroscopy, and mass spectrometry of a series of linear triphenylphosphine gold(I) complexes with substituted N-heterocycle ligands (L), [(PPh3)Au(I)(L)](+), is reported. The reaction of [(PPh3)Au(L)](+) (L = Cl(-) or substituted N- heterocyclic pyridine) with the C-terminal (Cys3His) finger of HIVNCp7 shows evidence by mass spectrometry (ESI-MS) and (31)P NMR spectroscopy of a long-lived {(PPh3)Au}-S-peptide species resulting from displacement of the chloride or pyridine ligand by zinc-bound cysteine with concomitant displacement of Zn(2+). In contrast, reactions with the Cys2His2 finger-3 of the Sp1 transcription factor shows significantly reduced intensities of {(PPh3)Au} adducts. The results suggest the possibility of systematic (electronic, steric) variations of "carrier" group PR3 and "leaving" group L as well as the nature of the zinc finger in modulation of biological activity. The cytotoxicity, cell cycle signaling effects, and cellular accumulation of the series are also reported. All compounds display cytotoxicity in the micromolar range upon 96 h continuous exposure to human tumor cells. The results may have relevance for the reported inhibition of viral load in simian virus by the gold(I) drug auranofin. PMID:24063530

  11. Studies toward an ideal fluorescence method to measure palladium in functionalized organic molecules: effects of sodium borohydride, temperature, phosphine ligand, and phosphate ions on kinetics.

    PubMed

    Song, Fengling; Carder, Evan J; Kohler, Clare C; Koide, Kazunori

    2010-12-01

    Residual metals in fine chemicals are currently detected by using inductively coupled plasma mass spectrometry, which requires expensive instrumentation and does not have high-throughput capabilities. Although fluorescent probes can be amenable to high-throughput analyses of metals, the utility of such analyses is limited due to the lack of generality. Herein, we report a significant improvement (≈19-fold) to our previously reported catalysis-based fluorescent probe for palladium. Specifically, we found that slightly elevated temperature dramatically improved the generality of the method and that the deallylation reaction of the nonfluorescent compound 1 was accelerated by phosphate ions in aqueous media. This method was capable of detecting 0.2 ppb palladium. We demonstrated reasonably accurate palladium detection in various active pharmaceutical ingredients and highly functionalized organic compounds. PMID:20938936

  12. Crystal structure of a samarium(III) nitrate chain cross-linked by a bis-carbamoyl-methyl-phosphine oxide ligand.

    PubMed

    Stoscup, Julie A; Staples, Richard J; Biros, Shannon M

    2014-10-01

    In the title compound poly[aqua-bis-(μ-nitrato-κ(4) O,O':O,O'')tetra-kis-(nitrato-κ(2) O,O'){μ4-tetra-ethyl [(ethane-1,2-diyl)bis(aza-nedi-yl)bis-(2-oxo-ethane-2,1-di-yl)]di-phospho-nate-κ(2) O,O'}disamarium(III)], [Sm2(NO3)6(C14H30N2O8P2)(H2O)] n , a 12-coordinate Sm(III) and a nine-coordinate Sm(III) cation are alternately linked via shared bis-bidentate nitrate anions into a corrugated chain extending parallel to the a axis. The nine-coordinate Sm(III) atom of this chain is also chelated by a bidentate, yet flexible, carbamoyl-methyl-phoshine oxide (CMPO) ligand and bears one water mol-ecule. This water mol-ecule is hydrogen bonded to nitrate groups bonded to the 12-coordinate Sm(III) cation. The CMPO ligand, which lies about an inversion center, links neighboring chains along the c axis, forming sheets parallel to the ac plane. Hydrogen bonds between the amide NH group and metal-bound nitrate anions are also present in these sheets. The sheets are packed along the b axis through only van der Waals inter-actions. PMID:25484648

  13. Aryl-palladium-NHC complex: efficient phosphine-free catalyst precursors for the carbonylation of aryl iodides with amines or alkynes.

    PubMed

    Zhang, Chunyan; Liu, Jianhua; Xia, Chungu

    2014-12-21

    A series of aryl-palladium-NHC compounds was prepared according to the reported methods and their catalytic activity in the carbonylation of aryl iodides to synthesize ?-keto amides and alkynones was examined. These practical aryl-palladium-NHC complexes have shown highly efficient catalyzed carbonylation and Sonogashira carbonylation reactions, with high turnover number in synthesis of ?-keto amides (TON = 4300) and in synthesis of alkynones (TON = 980). PMID:25350346

  14. Laboratory Measurements of the W-band (3.2 mm) Properties of Phosphine (PH3) and Ammonia (NH3) Under Simulated Conditions for the Outer Planets

    NASA Astrophysics Data System (ADS)

    Mohammed, P. N.; Steffes, P. G.

    2003-05-01

    A model, based on the Van Vleck-Weisskopf lineshape, was developed for the centimeter-wavelength opacity of PH3, which provides an order of magnitude improvement over previous models (Hoffman et al. ICARUS 152, 172-184, 2001). This formalism utilizes line intensities from the JPL (Pickett et al. 1998) catalog which have been selectively weighted to fit the centimeter wavelength laboratory data. The collisionally induced rotational lines which are lower in frequency than the first rotational line of J = 1 to 0 (267 GHz) have not been measured directly, thus in order to fit the data, weightings were given to those lines below 40 GHz. New laboratory measurements are currently being conducted to investigate whether this model is also accurate at 94 GHz (3.2 mm) under conditions for the outer planets. Preliminary measurements at room temperature agree well with this centimeter-wave formalism for PH3 opacity suggesting that the intensities of only the first 40 lines of the JPL catalog need to be weighted. Further measurements of the opacity and refractivity of PH3 in a hydrogen/helium (H2/He) atmosphere are being conducted at 94 GHz (3.2 mm) at pressures of 0.5, 1 and 2 bars and at temperatures of 210 K and 193 K. Additionally, new high-precision laboratory measurements of the opacity and refractivity of NH3 in an H2/He atmosphere will be conducted under the same frequency, temperature and pressure conditions described for PH3. These new measurements will better constrain the NH3 opacity model for use over a broader wavelength range. Results of measurements of both PH3 and NH3 can be used to better interpret maps of Saturn's emission at this wavelength and can potentially deduce spatial variations in the abundances of both gases in the atmosphere of Saturn. This work is supported by the NASA Planetary Atmospheres Program under grant NAG5-12122.

  15. Single-step co-deposition of nanostructured tungsten oxide supported gold nanoparticles using a gold-phosphine cluster complex as the gold precursor

    NASA Astrophysics Data System (ADS)

    Molkenova, Anara; Sarip, Rozie; Sathasivam, Sanjay; Umek, Polona; Vallejos, Stella; Blackman, Chris; Hogarth, Graeme; Sankar, Gopinathan

    2014-12-01

    The use of a molecular gold organometallic cluster in chemical vapour deposition is reported, and it is utilized, together with a tungsten oxide precursor, for the single-step co-deposition of (nanostructured) tungsten oxide supported gold nanoparticles (NPs). The deposited gold-NP and tungsten oxide supported gold-NP are highly active catalysts for benzyl alcohol oxidation; both show higher activity than SiO2 supported gold-NP synthesized via a solution-phase method, and tungsten oxide supported gold-NP show excellent selectivity for conversion to benzaldehyde.

  16. Molecular and biochemical evidence on the protection of cardiomyocytes from phosphine-induced oxidative stress, mitochondrial dysfunction and apoptosis by acetyl-l-carnitine.

    PubMed

    Baghaei, Amir; Solgi, Reza; Jafari, Abbas; Abdolghaffari, Amir Hossein; Golaghaei, Alireza; Asghari, Mohammad Hossein; Baeeri, Maryam; Ostad, Seyed Nasser; Sharifzadeh, Mohammad; Abdollahi, Mohammad

    2016-03-01

    The aim of the present study was to investigate the efficacy of acetyl-l-carnitine (ALCAR) on pathologic changes of mitochondrial respiratory chain activity, ATP production, oxidative stress, and cellular apoptosis/necrosis induced by aluminum phosphide (AlP) poisoning. The study groups included: the Sham that received almond oil only; the AlP that received oral LD50 dose of aluminum; the AC-100, AC-200, and AC-300 which received concurrent oral LD50 dose of AlP and single 100, 200, and 300mg/kg of ALCAR by intraperitoneal injection. After 24h, the rats were sacrificed; the heart and blood sample were taken for measurement of biochemical and mitochondrial factors. The results specified that ALCAR significantly attenuated the oxidative stress (elevated ROS and plasma iron levels) caused by AlP poisoning. ALCAR also increased the activity of cytochrome oxidase, which in turn amplified ATP production. Furthermore, flow cytometric assays and caspase activity indicated that ALCAR prohibited AlP-induced apoptosis in cardiomyocytes. PMID:26773361

  17. Spirobifluorene-2,7-dicarbazole-4'-phosphine Oxide as Host for High-Performance Single-Layer Green Phosphorescent OLED Devices.

    PubMed

    Thiery, Sébastien; Tondelier, Denis; Geffroy, Bernard; Jacques, Emmanuel; Robin, Malo; Métivier, Rémi; Jeannin, Olivier; Rault-Berthelot, Joëlle; Poriel, Cyril

    2015-10-01

    A new host material based on the 2,7,4'-substituted spirobifluorene platform has been designed and used in single-layer phosphorescent OLED with very high efficiency (EQE = 13.2%) and low turn-on voltage (2.4 V). This performance is among the best reported for green single-layer PhOLEDs and may open new avenues in the design of host materials for single-layer devices. PMID:26371550

  18. Extraction and coordination studies of a carbonyl-phosphine oxide scorpionate ligand with uranyl and lanthanide(iii) nitrates: structural, spectroscopic and DFT characterization of the complexes.

    PubMed

    Matveeva, Anna G; Vologzhanina, Anna V; Goryunov, Evgenii I; Aysin, Rinat R; Pasechnik, Margarita P; Matveev, Sergey V; Godovikov, Ivan A; Safiulina, Alfiya M; Brel, Valery K

    2016-03-15

    Hybrid scorpionate ligand (OPPh2)2CHCH2C(O)Me () was synthesized and characterized by spectroscopic methods and X-ray diffraction. The selected coordination chemistry of with UO2(NO3)2 and Ln(NO3)3 (Ln = La, Nd, Lu) has been evaluated. The isolated mono- and binuclear complexes, namely, [UO2(NO3)2] (), [{UO2(NO3)}2(μ2-O2)]·EtOH (), [La(NO3)32]·2.33MeCN (), [Nd(NO3)32]·3MeCN (), [Nd(NO3)22](+)·(NO3)(-)·EtOH () and [Lu(NO3)32] () have been characterized by IR spectroscopy and elemental analysis. Single-crystal X-ray structures have been determined for complexes . Intramolecular intraligand π-stacking interactions between two phenyl fragments of the coordinated ligand(s) were observed in all complexes . The π-stacking interaction energy was estimated from Bader's AIM theory calculations performed at the DFT level. Solution properties have been examined using IR and multinuclear ((1)H, (13)C, and (31)P) NMR spectroscopy in CD3CN and CDCl3. Coordination modes of vary with the coordination polyhedron of the metal and solvent nature showing many coordination modes: P(O),P(O), P(O),P(O),C(O), P(O),C(O), and P(O). Preliminary extraction studies of U(vi) and Ln(iii) (Ln = La, Nd, Ho, Yb) from 3.75 M HNO3 into CHCl3 show that scorpionate extracts f-block elements (especially uranium) better than its unmodified prototype (OPPh2)2CH2. PMID:26888745

  19. A Significantly Twisted Spirocyclic Phosphine Oxide as a Universal Host for High-Efficiency Full-Color Thermally Activated Delayed Fluorescence Diodes.

    PubMed

    Li, Jing; Ding, Dongxue; Tao, Youtian; Wei, Ying; Chen, Runfeng; Xie, Linghai; Huang, Wei; Xu, Hui

    2016-04-01

    A universal thermally activated delayed fluorescence (TADF) host, 4'-diphenylphosphinoylspiro[fluorene-9,9'-xanthene] (SFXSPO), is constructed with a highly distorted and asymmetric configuration and disordered molecular packing in its solid state. SFXSPO successfully endows its full-color TADF diodes with state-of-the-art performance, e.g., the record external quantum efficiency of 22.5% and 19.1% and internal quantum efficiency of ≈100% for its yellow TADF diodes and single-host full-TADF nearly-white-emitting devices, respectively. PMID:26923460

  20. Facile synthesis of phosphine free ultra-small PbSe nanocrystals and their light harvesting studies in ETA solar cells.

    PubMed

    Akhtar, Javeed; Banski, Mateusz; Malik, Mohammad Azad; Revaprasadu, Neerish; Podhorodecki, Artur; Misiewicz, Jan

    2014-11-21

    Ultra-small PbSe nanocrystals (NCs) were synthesized via a 'one-pot' approach in olive oil as the reaction medium and capping agent. The optical spectra showed discernible blue shifts in the absorption band edges (570-780 nm) due to strong quantum confinement effects and photoluminescence (PL) spectra showed significant strong emission peaks in the range of 780-850 nm. The broad peaks in the powder X-ray diffraction (p-XRD) pattern indicate the ultra-small size of the as-prepared NCs. These NCs were used to construct an extremely thin absorber (ETA) solar device after surface modification. The preliminary results indicate their potential as light harvesting entities in nanostructure based solar cells. PMID:25247625

  1. Cyclometallated platinum(II) complexes of benzylidene-2,6-di-isopropylphenylamine containing bidentate phosphines: synthesis, structural properties and reactivity studies.

    PubMed

    Zheng, Feng; Hutton, Alan T; van Sittert, Cornelia G C E; Gerber, Wilhelmus J; Mapolie, Selwyn F

    2015-01-28

    The reaction of the cyclometallated complex [PtCl(N^C)(dmso)], 1 (N^C represents the cyclometallated Schiff base, benzylidene-2,6-diisopropylphenylamine), with 1,1'-bis(diphenylphosphino)ferrocene, dppf, bis(diphenylphosphino)methane, dppm, or 1,2-bis(diphenylphosphino)ethane, dppe, in a 2 : 1 ratio or an equimolar ratio using acetone as the solvent produced the corresponding binuclear or mononuclear diphosphine platinum complexes. In the case of the mononuclear complexes, the diphosphines act as either a bidentate ligand or a monodentate ligand depending on the size of the bite angle of the diphosphines, while in the case of the binuclear complexes, the diphosphines act as a bridging ligand between the two metal centres. The solid state structures of some of the binuclear as well as mononuclear species are reported. The mononuclear derivatives were found to show different behaviour in solution and in the solid state when compared to the binuclear analogues. This behaviour is also influenced by the nature of the diphosphine ligands employed. PMID:25504380

  2. Extraction from HNO{sub 3} solutions and separation of Pu(IV) from Am(III) by diphenyl(dialkyl carbamoylmethyl)phosphine oxides

    SciTech Connect

    Litvina, M.N.; Chmutova, M.K.; Nesterova, N.P.

    1995-03-01

    Five carbamoylmethylphosphine oxide (CMPO) extractants with phenyl substituents on the P atom and alkyl groups (butyl, octyl, isoamyl) or cyclic hydrocarbons (piperidine, morpholine) on the N atom are used to study the extraction of Pu(IV) from HNO{sub 3} solutions by CMPO in a polar aromatic fluorinated diluent as a function of [HNO{sub 3}] and [CMPO]. All studied CMPOs quantitatively extract Pu(IV) from HNO{sub 3} with distribution coefficients that are 2-3 orders of magnitude greater than those of Am(III). The elements Pu and Am can be separated during back-extraction.

  3. Kinetic aspects for the reduction of CO₂ and CS₂ with mixed-ligand ruthenium(II) hydride complexes containing phosphine and bipyridine.

    PubMed

    Huang, Jing; Chen, Jinzhu; Gao, Hui; Chen, Limin

    2014-09-15

    A new water-soluble ruthenium hydride complex [Ru(H)(bpy)2(PTA)]PF6 (bpy = 2,2'-bipyridine, PTA = 1,3,5-triaza-7-phosphaadamantane) (1a) was prepared. 1a reacted with CO2 and CS2 to give the corresponding formate and dithioformate complexes, respectively. Both the insertions of CO2 and CS2 into the Ru-H bond of 1a followed second-order kinetics. The second-order rate constant (k2) of CO2 insertion reaction varied from (9.40 ± 0.41) × 10(-4) M(-1) s(-1) in acetone to (1.13 ± 0.08) × 10(-1) M(-1) s(-1) in methanol; moreover, the ln(k2) is in good linear relationship with the acceptor number (AN) of the solvent used. Although, the k2 of CS2 insertion reaction ranged from (3.43 ± 0.10) M(-1) s(-1) in methanol to (24.0 ± 0.5) M(-1) s(-1) in N,N-dimethylformamide, which is 1000 times faster than CO2 insertion. Generally, the k2 of CS2 insertion increased with the static dielectric constant (D(s)) of the reaction medium investigated. For comparison purposes, we further investigated the reactivity of [Ru(H)(bpy)2(PPh3)]PF6 (PPh3 = triphenylphosphine) (1b) with CO2 and CS2. 1b reacted with CO2 slowly in the methanol with a k2 of (1.46 ± 0.09) × 10(-3) M(-1) s(-1), yielding a formate complex [Ru(η(1)-OC(H)═O)(bpy)2(PPh3)]PF6 (2b). The reaction of 1b with CS2 is 1000 times faster than that of CO2. The structures of 1a, 1b, and 2b were determined by X-ray crystallographic analysis. PMID:25167462

  4. (Ammine)(carbon-yl)[hydridotris(pyrazol-1-yl-κN(2))borato](triphenyl-phosphine-κP)ruthenium(II) chloride dichloro-methane disolvate.

    PubMed

    Hu, Ting-Chuan; Ye, Jun-Xlan; He, Sheng-Ting; Chiang, Guan-Ru; Lo, Yih-Hsing

    2012-11-01

    In the title compound, [Ru(CO)(NH(3))(C(9)H(10)BN(6))(C(18)H(15)P)]Cl·2CH(2)Cl(2), the coordination environment around the Ru(II) atom is distorted octa-hedral. One of the Ru-N(Tp) [Tp = hydridotris(pyrazol-1-yl)borate] bond lengths is slightly longer than the other two as a result of the influence of the trans CO ligand. In the crystal, N-H⋯Cl hydrogen bonds link the complex cations and Cl(-) anions. π-π inter-actions between the pyrazole rings [centroid-centroid distance = 3.764 (3) Å] are also present. PMID:23284343

  5. Electronic communication in phosphine substituted bridged dirhenium complexes - clarifying ambiguities raised by the redox non-innocence of the C4H2- and C4-bridges.

    PubMed

    Li, Yan; Blacque, Olivier; Fox, Thomas; Luber, Sandra; Polit, Walther; Winter, Rainer F; Venkatesan, Koushik; Berke, Heinz

    2016-04-01

    The mononuclear rhenium carbyne complex trans-[Re(C[triple bond, length as m-dash]CSiMe3)([triple bond, length as m-dash]C-Me)(PMe3)4][PF6] (2) was prepared in 90% yield by heating a mixture of the dinitrogen complex trans-[ReCl(N2)(PMe3)4] (1), TlPF6, and an excess of HC[triple bond, length as m-dash]CSiMe3. 2 could be deprotonated with KOtBu to the vinylidene complex trans-[Re(C[triple bond, length as m-dash]CSiMe3)([double bond, length as m-dash]C[double bond, length as m-dash]CH2)(PMe3)4] (3) in 98% yield. Oxidation of 3 with 1.2 equiv. of [Cp2Fe][PF6] at -78 °C gave the Cβ-C'β coupled dinuclear rhenium biscarbyne complex trans-[(Me3SiC[triple bond, length as m-dash]C)(PMe3)4Re[triple bond, length as m-dash]C-CH2-CH2-C[triple bond, length as m-dash]Re(PMe3)4(C[triple bond, length as m-dash]CSiMe3)][PF6]2 (5) in 92% yield. Deprotonation of 5 with an excess of KOtBu in THF produced the diamagnetic trans-[(Me3SiC[triple bond, length as m-dash]C)(PMe3)4Re[double bond, length as m-dash]C[double bond, length as m-dash]CH-CH[double bond, length as m-dash]C[double bond, length as m-dash]Re(PMe3)4(C[triple bond, length as m-dash]CSiMe3)] complex (E-6(S)) in 87% yield with an E-butadienediylidene bridge. Density functional theory (DFT) calculations of E-6(S) confirmed its singlet ground state. The Z-form of 6 (Z-6(S)) could not be observed, which is in accord with its DFT calculated 17.8 kJ mol(-1) higher energy. Oxidation of E-6 with 2 equiv. of [Cp2Fe][PF6] resulted in the stable diamagnetic dicationic trans-[(Me3SiC[triple bond, length as m-dash]C)(PMe3)4Re[triple bond, length as m-dash]C-CH[double bond, length as m-dash]CH-C[triple bond, length as m-dash]Re(PMe3)4(C[triple bond, length as m-dash]CSiMe3)][PF6]2 complex (E-6[PF6]2) with an ethylenylidene dicarbyne structure of the bridge. The paramagnetic mixed-valence (MV) complex E-6[PF6] was obtained by comproportionation of E-6(S) and E-6[PF6]2 or by oxidation of E-6(S) with 1 equiv. of [Cp2Fe][PF6]. The dicationic trans-[(Me3SiC[triple bond, length as m-dash]C)(PMe3)4Re[triple bond, length as m-dash]C-C[triple bond, length as m-dash]C-C[triple bond, length as m-dash]Re(PMe3)4(C[triple bond, length as m-dash]CSiMe3)][PF6]2 (7[PF6]2) complex, attributed a butynedi(triyl) bridge structure, was obtained by deprotonation of E-6[PF6]2 with KOtBu followed by oxidation with 2 equiv. of [Cp2Fe][PF6]. The neutral complex 7 could be accessed best by reduction of 7[PF6]2 with KH in the presence of 18-crown-6. According to DFT calculations 7 possesses two equilibrating electronic states: diamagnetic 7(S) and triplet 7(F) with ferromagnetically coupled spins. The latter is calculated to be 5.2 kcal mol(-1) lower in energy than 7(S). There is experimental evidence that 7(S) prevails in solution. 7 could not be isolated in the crystalline state and is unstable transforming mainly by H-abstraction to give E-6(S). UV-Vis-NIR spectroscopy for the dinuclear rhenium complexes E-6(S), E-6[PF6] and E-6[PF6]2, as well as EPR spectroscopic and variable-temperature magnetization measurements for the MV complex E-6[PF6] were also conducted. Spectro-electrochemical reduction studies on 7[PF6]2 allowed the characterization of the mono- and direduced forms of 7(+) and 7 by means of IR- and UV-Vis-NIR-spectroscopy and revealed the chemical fate of the higher reduced form. PMID:26936132

  6. Synthesis of Ruthenium Carbonyl Complexes with Phosphine or Substituted Cp Ligands, and Their Activity in the Catalytic Deoxygenation of 1,2-Propanediol

    SciTech Connect

    Bullock, R.M.; Ghosh, P.; Fagan, P.J.; Marshall, W.J.; Hauptman, E.

    2009-07-20

    A ruthenium hydride with a bulky tetra-substituted Cp ligand, (Cp{sup iPr{sub 4}})Ru(CO){sub 2}H (Cp{sup iPr{sub 4}} = C{sub 5}(i-C{sub 3}H{sub 7}){sub 4}H) was prepared from the reaction of Ru{sub 3}(CO){sub 12} with 1,2,3,4-tetraisopropylcyclopentadiene. The molecular structure of (Cp{sup iPr{sub 4}})Ru(CO){sub 2}H was determined by X-ray crystallography. The ruthenium hydride complex (C{sub 5}Bz{sub 5})Ru(CO){sub 2}H (Bz = CH{sub 2}Ph) was similarly prepared. The Ru-Ru bonded dimer, [(1,2,3-trimethylindenyl)Ru(CO){sub 2}]{sub 2}, was produced from the reaction of 1,2,3-trimethylindene with Ru{sub 3}(CO){sub 12}, and protonation of this dimer with HOTf gives {l_brace}[(1,2,3-trimethylindenyl)Ru(CO){sub 2}]{sub 2}-({mu}-H){r_brace}{sup +}OTf{sup -}. A series of ruthenium hydride complexes CpRu(CO)(L)H [L = P(OPh){sub 3}, PCy{sub 3}, PMe{sub 3}, P(p-C{sub 6}H{sub 4}F){sub 3}] were prepared by reaction of Cp(CO){sub 2}RuH with added L. Protonation of (Cp{sup iPr{sub 4}})Ru(CO){sub 2}H, Cp*Ru(CO){sub 2}H, or CpRu(CO)[P-(OPh){sub 3}]H by HOTf at -80 C led to equilibria with the cationic dihydrogen complexes, but H{sub 2} was released at higher temperatures. Protonation of CpRu[P(OPh){sub 3}]{sub 2}H with HOTf gave an observable dihydrogen complex, {l_brace}CpRu[P-(OPh){sub 3}]{sub 2}({eta}{sup 2}-H{sub 2}){r_brace}+OTf{sup -} that was converted at -20 C to the dihydride complex {l_brace}CpRu[P(OPh){sub 3}]{sub 2}(H){sub 2}{r_brace}{sup +}OTf{sup -}. These Ru complexes serve as catalyst precursors for the catalytic deoxygenation of 1,2-propanediol to give n-propanol. The catalytic reactions were carried out in sulfolane solvent with added HOTf under H{sub 2} (750 psi) at 110 C.

  7. Carboranylphosphinic Acids: A New Class of Purely Inorganic Ligands.

    PubMed

    Oleshkevich, Elena; Teixidor, Francesc; Choquesillo-Lazarte, Duane; Sillanpää, Reijo; Viñas, Clara

    2016-03-01

    Purely inorganic carboranyl phosphinates were prepared, and the influence of the cluster on the reactivity of the phosphinate group was studied. Electron-withdrawal by the carboranyl carbon atoms, combined with space-filling efficiency and enhanced aromaticity of the cluster cage, renders the phosphorus more difficult to oxidize. This enables carboranyl phosphinates to survive harsh oxidizing conditions, a property which is uncommon in organic phosphinates. PMID:26638876

  8. Synergistic extraction of Eu(III) and Am(III) by thenoyltrifluoroacetone and neutral donor extractants: (Carbamoylmethyl)phosphine oxide and 2,6-bis((diphenylphosphino)methyl)pyridine N,P,P,-trioxide

    SciTech Connect

    Rao, L.; Xia, Y.; Rapko, B.M.; Martin, P.F.

    1998-07-01

    Solvent extraction of Eu(III) and Am(III) from weakly acidic solutions with octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) and 2,6-bis((diphenylphosphino)methyl)pyridine N,P,P-trioxide (NOPOPO) in 1,2-dichloroethane was studied on a comparative basis. NOPOPO was found to exhibit unusually high extractability for Eu(III) and Am(III), probably due to its trifunctional nature, sufficient steric flexibility and basicity of the functional groups. Both CMPO and NOPOPO demonstrated synergistic effects in extraction of Eu(III) and Am(III) when used in combination with thenoyltrifluoroacetone (HTTA). However, the stoichiometry of the extracted species with CMPO/HTTA and NOPOPO/HTTA was different under similar experimental conditions. The extractant dependencies of the synergistic extractions suggest that the extracted species are the adduct complexes, M(ClO{sub 4})(TTA){sub 2}(CMPO){sub 2} and M(ClO{sub 4}){sub 2}(TTA)(NOPOPO){sub 2}, respectively. It was also observed that CMPO and CMPO/HTTA in dichloroethane extracted Eu(III) and Am(III) equally well, with very similar extraction constants. However, NOPOPO and NOPOPO/HTTA in dichloroethane demonstrated a slight preference for Eu(III) over Am(III), with the extraction constants for Eu(III) more than one order of magnitude higher than that for Am(III).

  9. Synthesis, characterization, X-ray structure and in vitro antimycobacterial and antitumoral activities of Ru(II) phosphine/diimine complexes containing the "SpymMe2" ligand, SpymMe2=4,6-dimethyl-2-mercaptopyrimidine.

    PubMed

    do Nascimento, Fábio B; Von Poelhsitz, Gustavo; Pavan, Fernando R; Sato, Daisy N; Leite, Clarice Q F; Selistre-de-Araújo, Heloisa S; Ellena, Javier; Castellano, Eduardo E; Deflon, Victor M; Batista, Alzir A

    2008-09-01

    The reaction of cis-[RuCl(2)(dppb)(N-N)], dppb=1,4-bis(diphenylphosphino)butane, complexes with the ligand HSpymMe(2), 4,6-dimethyl-2-mercaptopyrimidine, yielded the cationic complexes [Ru(SpymMe(2))(dppb)(N-N)]PF(6), N-N=bipy (1) and Me-bipy (2), bipy=2,2'-bipyridine and Me-bipy=4,4'-dimethyl-2,2'-bipyridine, which were characterized by spectroscopic and electrochemical techniques and X-ray crystallography and elemental analysis. Additionally, preliminary in vitro tests for antimycobacterial activity against Mycobacterium tuberculosis H37Rv ATCC 27264 and antitumor activity against the MDA-MB-231 human breast tumor cell line were carried out on the new complexes and also on the precursors cis-[RuCl(2)(dppb)(N-N)], N-N=bipy (3) and Me-bipy (4) and the free ligands dppb, bipy, Me-bipy and SpymMe(2). The minimal inhibitory concentration (MIC) of compounds needed to kill 90% of mycobacterial cells and the IC(50) values for the antitumor activity were determined. Compounds 1-4 exhibited good in vitro activity against M. tuberculosis, with MIC values ranging between 0.78 and 6.25microg/mL, compared to the free ligands (MIC of 25 to >50microg/mL) and the drugs used to treat tuberculosis. Complexes 1 and 2 also showed promising antitumor activity, with IC(50) values of 0.46+/-0.02 and 0.43+/-0.08microM, respectively, against MDA-MB-231 breast tumor cells. PMID:18614238

  10. Green synthesis of Pd/CuO nanoparticles by Theobroma cacao L. seeds extract and their catalytic performance for the reduction of 4-nitrophenol and phosphine-free Heck coupling reaction under aerobic conditions.

    PubMed

    Nasrollahzadeh, Mahmoud; Sajadi, S Mohammad; Rostami-Vartooni, Akbar; Bagherzadeh, Mojtaba

    2015-06-15

    We report the green synthesis of palladium/CuO nanoparticles (Pd/CuO NPs) using Theobroma cacao L. seeds extract and their catalytic activity for the reduction of 4-nitrophenol and Heck coupling reaction under aerobic conditions. The catalyst was characterized using the powder XRD, TEM, EDS, UV-vis and FT-IR. This method has the advantages of high yields, elimination of surfactant, ligand and homogeneous catalysts, simple methodology and easy work up. The catalyst can be recovered from the reaction mixture and reused several times without any significant loss of catalytic activity. PMID:25721860

  11. Synthesis and characterization of technetium(III) and technetium(II) complexes with mixed phosphine-, chloride, and nitrogen-donor ligands. X-ray crystal structure of TcCl sub 3 (PPh sub 3 )(bpy)

    SciTech Connect

    Breikss, A.I.; Nicholson, T.; Davison, A. ); Jones, A.G. )

    1990-02-21

    The synthesis and characterization of Tc(III) complexes of the types TcCl{sub 3}(PMe{sub 2}Ph)(LL) and TcCl{sub 2}(PMe{sub 2}Ph){sub 2}(LL){sup +}, the neutral Tc(II) series TcCl{sub 2}(PMe{sub 2}Ph){sub 2}(LL), and the Tc(II) complex TcCl(PMe{sub 2}Ph){sub 3}(bpy){sup +} are reported (LL = 2,2{prime}-bipyridine (bpy), 1,10-phenanthroline (phen), 2,2{prime}-bipyrimidine (bpm)). The Tc(III) complexes exhibit contact-shifted {sup 1}H NMR spectra with relatively narrow line widths; the Tc(II) species give less well-defined spectra. The electrochemistry of these complexes is discussed as well. An x-ray structure determination of TcCl{sub 3}(PPh{sub 3})(bpy) was performed. Crystal data for C{sub 28}H{sub 23}Cl{sub 3}N{sub 2}PTc: monoclinic, space group = P2{sub 1}/n, a = 10.980 (2) {angstrom}, b = 24.336 (5) {angstrom}, c = 10.172 (2) {angstrom}, {beta} = 106.89 (1){degree}, V = 2,600.9 (8) {angstrom}{sup 3} to give Z = 4. Structure solution and refinement based on 4,366 reflections converged at R = 0.057 and R{sub w} = 0.074. 25 refs., 4 figs., 5 tabs.

  12. Metal-metal multiply-bonded complexes of technetium. 3. Preparation and characterization of phosphine complexes of technetium possessing a metal-metal bond order of 3.5

    SciTech Connect

    Cotton, F.A.; Haefner, S.C.; Sattelberger, A.P.

    1996-03-27

    Two new ditechnetium complexes possessing Tc-Tc bonds with a formal bond order of 3.5 have been prepared in high yield. Mild chemical oxidation of Tc{sub 2}Cl{sub 4}(PMe{sub 2}Ph){sub 4} with ferrocenium hexafluorophosphate in acetonitrile produces [Tc{sub 2}Cl{sub 4}(PMe{sub 2}Ph){sub 4}][PF{sub 6}] (1) in 82% yield. One-electron oxidation of Tc{sub 2}Cl{sub 4}(PMe{sub 2}Ph){sub 4} by ferrocenium hexafluorophosphate in the presence of ppnCl (ppn = bis(triphenylphosphine)iminium) yielded the neutral compound Tc{sub 2}Cl{sub 5}(PMe{sub 2}Ph){sub 3} (2) in 89% yield. Both species are paramagnetic, as evidenced by EPR spectroscopy, and possess a {sigma}{sup 2}{pi}{sup 4}{delta}{sup 2}{delta}{sup *} ground state electronic configuration on the basis of structural and spectroscopic data. The solid state structures of three forms of 1 have been investigated by X-ray crystallography together with the structure of 2. Electrochemical studies reveal that both compounds are capable of undergoing a one-electron oxidation and a one-electron reduction to yield the respective Tc{sub 2}{sup 6+} and Tc{sub 2}{sup 4+} dinuclear cores. IR, EPR, and UV-vis spectroscopic data are presented for compounds 1 and 2.

  13. Synthesis of tetraphosphine macrocycles using copper(i) templates.

    PubMed

    Nell, Bryan P; Swor, Charles D; Henle, E Adrian; Zakharov, Lev N; Rinehart, N Ian; Nathan, Aditya; Tyler, David R

    2016-05-10

    The synthesis of phosphine macrocycles is a relatively underdeveloped area and no standard synthetic routes have emerged. Accordingly, two general synthetic routes to tetradentate phosphine macrocycles were investigated. Both routes use Cu(i) ions as template ions because, unlike other metals such as Pd(ii) and Pt(ii), the Cu(i) ions can be removed from the macrocyclic complex without degrading the macrocycle ligand. The first route involves the coupling of two bidentate secondary phosphines bonded to Cu(i) using 1,3-dibromopropane or 1,4-dibromobutane. Using this route, tetradentate phosphine macrocycles with either -(CH2)3OCH3 or Ph groups bonded to the P atoms were synthesized. Macrocycle phosphines containing the -(CH2)3OCH3 groups were investigated for their potential water-solubility, but experiments showed these phosphines were not water soluble. The second synthetic route involved the alkylation of an open-chain, mixed tertiary-secondary, tetradentate phosphine coordinated to Cu(i). Following formation of the macrocyclic ligand, the Cu(i) template was removed by reaction with aqueous KCN to yield the free macrocyclic phosphine. This route was demonstrated for the preparation of the macrocyclic phosphine ligand 1,5,9,13-tetraphenyl-1,5,9,13-tetraphosphacycloheptadecane. Following demetallation, this macrocyclic ligand was coordinated to Fe(ii) and Co(ii) to form the corresponding macrocyclic phosphine complexes. PMID:27103545

  14. Recent Developments in the Addition of Phosphinylidene-Containing Compounds to Unactivated Unsaturated Hydrocarbons: Phosphorus-Carbon Bond-Formation via Hydrophosphinylation and Related Processes

    PubMed Central

    Coudray, Laëtitia

    2012-01-01

    Summary The reactions of phosphinylidene-containing compounds with unactivated unsaturated hydrocarbons are reviewed. The review is organized by phosphorus-containing functional group types. Free-radical and metal-catalyzed additions of R1R2P(O)H to alkenes, alkynes, and related compounds, deliver functionalized organophosphorus compounds RP(O)R1R2, including H-phosphinates, phosphinates, tertiary phosphine oxides, and phosphonates. The review covers the literature up to February 2008. PMID:23308039

  15. Conjugate and method for forming aminomethyl phosphorus conjugates

    DOEpatents

    Katti, Kattesh V.; Berning, Douglas E.; Volkert, Wynn A.; Ketring, Alan R.; Churchill, Robert

    1999-01-01

    A method of forming phosphine-amine conjugates includes reacting a hydroxymethyl phosphine group of an amine-free first molecule with at least one free amine group of a second molecule to covalently bond the first molecule with the second molecule through an aminomethyl phosphorus linkage and the conjugates formed thereby.

  16. Poly(arylene ether)s That Resist Atomic Oxygen

    NASA Technical Reports Server (NTRS)

    Connell, John W.; Hergenrother, Paul; Smith, Joseph G., Jr.

    1994-01-01

    Novel poly(arylene ether)s containing phosphine oxide (PAEPO's) made via aromatic nucleophilic displacement reactions of activated aromatic dihalides (or, in some cases, activated aromatic dinitro compounds) with new bisphenol monomers containing phosphine oxide. Exhibited favorable combination of physical and mechanical properties and resistance to monatomic oxygen in oxygen plasma environment. Useful as adhesives, coatings, films, membranes, moldings, and composite matrices.

  17. Hydroformylation: An Old Yet New Industrial Route to Alcohols.

    ERIC Educational Resources Information Center

    Pruett, Roy L.

    1986-01-01

    Discusses trends in hydroformylation chemistry, considering these catalysis and ligands: (1) cobalt, (2) cobalt-phosphine, and (3) rhodium-phosphine. Indicates that rhodium technology will grow in domination of hydroformylation practice. In addition, processes adapted to special cases of functional olefins and to higher olefins can be expected.…

  18. Umpolung of methylenephosphonium ions in their manganese half-sandwich complexes and application to the synthesis of chiral phosphorus-containing ligand scaffolds.

    PubMed

    Valyaev, Dmitry A; Filippov, Oleg A; Lugan, Noël; Lavigne, Guy; Ustynyuk, Nikolai A

    2015-05-18

    Half-sandwich manganese methylenephosphonium complexes [Cp(CO)2Mn(η(2)-R2P=C(H)Ph)]BF4 were obtained in high yield through a straightforward reaction sequence involving a classical Fischer-type manganese complex and a secondary phosphine as key starting materials. The addition of various nucleophiles (Nu) to these species took place regioselectively at the double-bonded carbon center of the coordinated methylenephosphonium ligand R2P(+)=C(H)Ph to produce the corresponding chiral phosphine complexes [Cp(CO)2Mn(κ(1)-R2P-C(H)(Ph)Nu)], from which the phosphines were ultimately recovered as free entities upon simple irradiation with visible light. The synthetic potential of this umpolung approach is illustrated herein by the preparation of novel chiral pincer-type phosphine-NHC-phosphine ligand architectures. PMID:25832414

  19. Interaction of some extreme-pressure type lubricating compounds with an iron surface

    NASA Technical Reports Server (NTRS)

    Buckley, D. H.

    1973-01-01

    An iron surface was exposed to the extreme-pressure type lubricant benzyl chloride, dichlorophenyl phosphine, dichlorophenyl phosphine sulfide, ophenyl phosphine oxide. Iron, in the sputter-cleaned state, was exposed to these materials statically and during dynamic friction experiments. With benzyl chloride only chlorine adsorbed to the surface, and with dichlorophenyl phosphine no adsorption occurred, while the addition of sulfur to that same molecular structure resulted in the promotion of carbon and chlorine adsorption. substitution of oxygen for sulfur in the dichlorobenzyl phosphine molecule resulted in carbon, chlorine, and oxygen adsorption. With none of the phosphorus containing molecules was phosphorus detected on the surface. Sliding in an atmosphere of benzyl chloride promoted adsorption of chlorine to the iron surface. Increases in load resulted in a decrease in the surface concentration of iron chloride.

  20. Phospha-Michael Addition as a New Click Reaction for Protein Functionalization.

    PubMed

    Lee, Yan-Jiun; Kurra, Yadagiri; Liu, Wenshe R

    2016-03-15

    A new type of click reaction between an alkyl phosphine and acrylamide was developed and applied for site-specific protein labeling in vitro and in live cells. Acrylamide is a small electrophilic olefin that readily undergoes phospha-Michael addition with an alkyl phosphine. Our kinetic study indicated a second-order rate constant of 0.07 m(-1)  s(-1) for the reaction between tris(2-carboxyethyl)phosphine and acrylamide at pH 7.4. To demonstrate its application in protein functionalization, we used a dansyl-phosphine conjugate to successfully label proteins that were site-specifically installed with N(ɛ) -acryloyl-l-lysine and employed a biotin-phosphine conjugate to selectively probe human proteins that were metabolically labeled with N-acryloyl-galactosamine. PMID:26756316

  1. Systems and strippable coatings for decontaminating structures that include porous material

    DOEpatents

    Fox, Robert V.; Avci, Recep; Groenewold, Gary S.

    2011-12-06

    Methods of removing contaminant matter from porous materials include applying a polymer material to a contaminated surface, irradiating the contaminated surface to cause redistribution of contaminant matter, and removing at least a portion of the polymer material from the surface. Systems for decontaminating a contaminated structure comprising porous material include a radiation device configured to emit electromagnetic radiation toward a surface of a structure, and at least one spray device configured to apply a capture material onto the surface of the structure. Polymer materials that can be used in such methods and systems include polyphosphazine-based polymer materials having polyphosphazine backbone segments and side chain groups that include selected functional groups. The selected functional groups may include iminos, oximes, carboxylates, sulfonates, .beta.-diketones, phosphine sulfides, phosphates, phosphites, phosphonates, phosphinates, phosphine oxides, monothio phosphinic acids, and dithio phosphinic acids.

  2. Polyphosphazine-based polymer materials

    DOEpatents

    Fox, Robert V.; Avci, Recep; Groenewold, Gary S.

    2010-05-25

    Methods of removing contaminant matter from porous materials include applying a polymer material to a contaminated surface, irradiating the contaminated surface to cause redistribution of contaminant matter, and removing at least a portion of the polymer material from the surface. Systems for decontaminating a contaminated structure comprising porous material include a radiation device configured to emit electromagnetic radiation toward a surface of a structure, and at least one spray device configured to apply a capture material onto the surface of the structure. Polymer materials that can be used in such methods and systems include polyphosphazine-based polymer materials having polyphosphazine backbone segments and side chain groups that include selected functional groups. The selected functional groups may include iminos, oximes, carboxylates, sulfonates, .beta.-diketones, phosphine sulfides, phosphates, phosphites, phosphonates, phosphinates, phosphine oxides, monothio phosphinic acids, and dithio phosphinic acids.

  3. Brønsted acid-catalyzed intramolecular nucleophilic substitution of the hydroxyl group in stereogenic alcohols with chirality transfer.

    PubMed

    Bunrit, Anon; Dahlstrand, Christian; Olsson, Sandra K; Srifa, Pemikar; Huang, Genping; Orthaber, Andreas; Sjöberg, Per J R; Biswas, Srijit; Himo, Fahmi; Samec, Joseph S M

    2015-04-15

    The hydroxyl group of enantioenriched benzyl, propargyl, allyl, and alkyl alcohols has been intramolecularly displaced by uncharged O-, N-, and S-centered nucleophiles to yield enantioenriched tetrahydrofuran, pyrrolidine, and tetrahydrothiophene derivatives with phosphinic acid catalysis. The five-membered heterocyclic products are generated in good to excellent yields, with high degree of chirality transfer, and water as the only side-product. Racemization experiments show that phosphinic acid does not promote SN1 reactivity. Density functional theory calculations corroborate a reaction pathway where the phosphinic acid operates as a bifunctional catalyst in the intramolecular substitution reaction. In this mechanism, the acidic proton of the phosphinic acid protonates the hydroxyl group, enhancing the leaving group ability. Simultaneously, the oxo group of phosphinic acid operates as a base abstracting the nucleophilic proton and thus enhancing the nucleophilicity. This reaction will open up new atom efficient techniques that enable alcohols to be used as nucleofuges in substitution reactions in the future. PMID:25803790

  4. Methods for removing contaminant matter from a porous material

    DOEpatents

    Fox, Robert V. [Idaho Falls, ID; Avci, Recep [Bozeman, MT; Groenewold, Gary S. [Idaho Falls, ID

    2010-11-16

    Methods of removing contaminant matter from porous materials include applying a polymer material to a contaminated surface, irradiating the contaminated surface to cause redistribution of contaminant matter, and removing at least a portion of the polymer material from the surface. Systems for decontaminating a contaminated structure comprising porous material include a radiation device configured to emit electromagnetic radiation toward a surface of a structure, and at least one spray device configured to apply a capture material onto the surface of the structure. Polymer materials that can be used in such methods and systems include polyphosphazine-based polymer materials having polyphosphazine backbone segments and side chain groups that include selected functional groups. The selected functional groups may include iminos, oximes, carboxylates, sulfonates, .beta.-diketones, phosphine sulfides, phosphates, phosphites, phosphonates, phosphinates, phosphine oxides, monothio phosphinic acids, and dithio phosphinic acids.

  5. Resolution of P-stereogenic P-heterocycles via the formation of diastereomeric molecular and coordination complexes (a review).

    PubMed

    Bagi, Pter; Ujj, Viktria; Czugler, Mtys; Fogassy, Elemr; Keglevich, Gyrgy

    2016-02-01

    TADDOL derivatives and the Ca(2+)-salts of tartaric acid derivatives were found to be versatile and generally applicable resolving agents for the preparation of the enantiomers of P-stereogenic heterocyclic phosphine oxides and phosphinates via the formation of the corresponding diastereomeric molecular and coordination complexes. A few of the diastereomeric intermediates were characterized by single crystal X-ray crystallography to gain insights into the binding mode of the corresponding heterocyclic phosphine oxide ("guest") and the resolving agent ("host") and to study the underlying phenomenon of enantiomeric recognition. PMID:26564410

  6. Synthesis and Characterization of Mixed Substituent P-n-Propyl-N-trimethylphosphoranimines

    SciTech Connect

    Klaehn, John Ray; Luther, Thomas Alan; Harrup, Mason Kurt; Stewart, Frederick Forrest

    2003-07-01

    One approach to the synthesis of polyphosphazenes is the condensation polymerization of phosphoranimines. In this work, several novel P-n-propyl-N-trimethylsilylphosphoranimines have been synthesized and characterized. Modifications to the literature synthetic routes were required to obtain the precursor phosphines. The N-trimethylsilylphosphoranimines were obtained though oxidation of the phosphine with bromine and then subsequent nucleophilic displacement using lithium phenoxide. These phosphoranimines were stable for long periods of time under dry inert conditions. NMR analyses revealed complex splitting patterns beyond typical coupling due to the stereocenter at phosphorus. We report several approaches to the n-propyl containing phosphines

  7. Synthesis of γ-hydroxypropyl P-chirogenic (±)-phosphorus oxide derivatives by regioselective ring-opening of oxaphospholane 2-oxide precursors.

    PubMed

    Binyamin, Iris; Meidan-Shani, Shoval; Ashkenazi, Nissan

    2015-01-01

    The synthesis of P-chirogenic (±)-phosphine oxides and phosphinates via selective nucleophilic ring opening of the corresponding oxaphospholanes is described. Two representative substrates: the phosphonate 2-ethoxy-1,2-oxaphospholane 2-oxide and the phosphinate 2-phenyl-1,2-oxaphospholane 2-oxide were reacted with various Grignard reagents to produce a single alkyl/aryl product. These products may possess further functionalities in addition to the phosphorus center such as the γ-hydroxypropyl group which results from the ring opening and π-donor moieties such as aryl, allyl, propargyl and allene which originates from the Grignard reagent. PMID:26425187

  8. Phosphorus-based fatty acid methyl esters.

    PubMed

    Katir, Nadia; El Kadib, Abdelkrim; Castel, Annie

    2013-09-01

    With the aim of designing novel transformable fatty acid diesters, various strategies for introducing phosphorus arms to the fatty backbone have been examined. While lithiated phosphine reacts classically to brominated fatty esters to afford the mono-addition product, the synthesis of phosphorylated diesters was found to be difficult, a fact related to the bulkiness of fatty acids and phosphine reagents. A base-induced dehydrochlorination reaction using ArPCl2 and hydroxy-terminated fatty esters resulted in metastable diester for which hydrolytic cleavage undergo phosphine oxidation and expulsion of one fatty chain. Alternatively, ArPOCl2 alleviates this drawback and provides stable, phosphorylated fatty acid diesters. PMID:23845998

  9. Synthesis of ?-hydroxypropyl P-chirogenic ()-phosphorus oxide derivatives by regioselective ring-opening of oxaphospholane 2-oxide precursors

    PubMed Central

    Binyamin, Iris; Meidan-Shani, Shoval

    2015-01-01

    Summary The synthesis of P-chirogenic ()-phosphine oxides and phosphinates via selective nucleophilic ring opening of the corresponding oxaphospholanes is described. Two representative substrates: the phosphonate 2-ethoxy-1,2-oxaphospholane 2-oxide and the phosphinate 2-phenyl-1,2-oxaphospholane 2-oxide were reacted with various Grignard reagents to produce a single alkyl/aryl product. These products may possess further functionalities in addition to the phosphorus center such as the ?-hydroxypropyl group which results from the ring opening and ?-donor moieties such as aryl, allyl, propargyl and allene which originates from the Grignard reagent. PMID:26425187

  10. Phosphonium Formation by Facile Carbon-Phosphorus Reductive Elimination from Gold(III).

    PubMed

    Kawai, Hiroyuki; Wolf, William J; DiPasquale, Antonio G; Winston, Matthew S; Toste, F Dean

    2016-01-20

    A recent trend in homogeneous gold catalysis has been the development of oxidative transformations relying on Au(I)/Au(III) redox cycling. Typically, phosphine-supported Au(I) precatalysts are used in the presence of strong oxidants to presumably generate phosphine Au(III) intermediates. Herein, we disclose that such Au(III) complexes can undergo facile Caryl-P reductive elimination to afford phosphonium salts, which have been spectroscopically and crystallographically characterized. Mechanistic studies indicate that this process occurs from cationic species at temperatures as low as -20 C but can be accelerated in the presence of nucleophiles, such as acetonitrile and phosphines, via a five-coordinate intermediate. Importantly, this study highlights that irreversible Caryl-P reductive elimination is a feasible decomposition or activation pathway for phosphine-supported Au(III) catalysts and should not be ignored in future reaction development. PMID:26744765

  11. High yield carbonylation of halo-hydrocarbons

    SciTech Connect

    Epstein, R.A.

    1987-05-26

    A process is described for carbonylating halo-hydrocarbons comprising carbonylating the halo-hydrocarbon in the presence of an alcohol, CO, a hindered amine base in conjunction with a palladium catalyst and an excess of phosphine.

  12. Elastomer-modified phosphorus-containing imide resins

    NASA Technical Reports Server (NTRS)

    Varma, I. K.; Fohlen, G. M.; Parker, J. A. (Inventor)

    1983-01-01

    Phosphine oxide-containing polyimide resins modified by elastomers, are disclosed which have improved mechanical properties. These products are particularly useful in the production of fiber or fabric-reinforced composites or laminates.

  13. Gold(I)-Catalyzed Enantioselective Intramolecular Hydroamination of Allenes with Ureas

    PubMed Central

    Li, Hao; Lee, Seong Du; Widenhoefer, Ross A.

    2011-01-01

    Enantioselective intramolecular hydroamination of N-allenyl ureas catalyzed by an enantiomerically enriched bis(gold) phosphine complex forms pyrrolidine derivatives in good yield with up to 93% ee. PMID:21909160

  14. Combined (Super 31)P and (Super 1)H NMR Experiments in the Structural Elucidation of Polynuclear Thiolate Complexes

    ERIC Educational Resources Information Center

    Cerrada, Elena; Laguna, Mariano

    2005-01-01

    A facile synthesis of two gold(I) complexes with 1,2-benzenedithiolate ligand and two different bidentate phosphines are described. A detailed sequence of NMR experiments is suggested to determine the structure of the compounds.

  15. Chemoselective ligation

    DOEpatents

    Saxon, Eliana; Bertozzi, Carolyn R.

    2010-02-23

    The present invention features a chemoselective ligation reaction that can be carried out under physiological conditions. In general, the invention involves condensation of a specifically engineered phosphine, which can provide for formation of an amide bond between the two reactive partners resulting in a final product comprising a phosphine moiety, or which can be engineered to comprise a cleavable linker so that a substituent of the phosphine is transferred to the azide, releasing an oxidized phosphine byproduct and producing a native amide bond in the final product. The selectivity of the reaction and its compatibility with aqueous environments provides for its application in vivo (e.g. on the cell surface or intracellularly) and in vitro (e.g., synthesis of peptides and other polymers, production of modified (e.g., labeled) amino acids).

  16. Chemoselective ligation

    DOEpatents

    Saxon, Eliana; Bertozzi, Carolyn Ruth

    2011-12-13

    The present invention features a chemoselective ligation reaction that can be carried out under physiological conditions. In general, the invention involves condensation of a specifically engineered phosphine, which can provide for formation of an amide bond between the two reactive partners resulting in a final product comprising a phosphine moiety, or which can be engineered to comprise a cleavable linker so that a substituent of the phosphine is transferred to the azide, releasing an oxidized phosphine byproduct and producing a native amide bond in the final product. The selectivity of the reaction and its compatibility with aqueous environments provides for its application in vivo (e.g., on the cell surface or intracellularly) and in vitro (e.g., synthesis of peptides and other polymers, production of modified (e.g., labeled) amino acids).

  17. Chemoselective ligation

    DOEpatents

    Saxon, Eliana; Bertozzi, Carolyn

    2003-05-27

    The present invention features a chemoselective ligation reaction that can be carried out under physiological conditions. In general, the invention involves condensation of a specifically engineered phosphine, which can provide for formation of an amide bond between the two reactive partners resulting in a final product comprising a phosphine moiety, or which can be engineered to comprise a cleavable linker so that a substituent of the phosphine is transferred to the azide, releasing an oxidized phosphine byproduct and producing a native amide bond in the final product. The selectivity of the reaction and its compatibility with aqueous environments provides for its application in vivo (e.g., on the cell surface or intracellularly) and in vitro (e.g., synthesis of peptides and other polymers, production of modified (e.g., labeled) amino acids).

  18. Chemoselective ligation

    DOEpatents

    Saxon, Eliana; Bertozzi, Carolyn Ruth

    2010-11-23

    The present invention features a chemoselective ligation reaction that can be carried out under physiological conditions. In general, the invention involves condensation of a specifically engineered phosphine, which can provide for formation of an amide bond between the two reactive partners resulting in a final product comprising a phosphine moiety, or which can be engineered to comprise a cleavable linker so that a substituent of the phosphine is transferred to the azide, releasing an oxidized phosphine byproduct and producing a native amide bond in the final product. The selectivity of the reaction and its compatibility with aqueous environments provides for its application in vivo (e.g., on the cell surface or intracellularly) and in vitro (e.g., synthesis of peptides and other polymers, production of modified (e.g., labeled) amino acids).

  19. Chemoselective ligation

    DOEpatents

    Saxon, Eliana; Bertozzi, Carolyn R.

    2011-05-10

    The present invention features a chemoselective ligation reaction that can be carried out under physiological conditions. In general, the invention involves condensation of a specifically engineered phosphine, which can provide for formation of an amide bond between the two reactive partners resulting in a final product comprising a phosphine moiety, or which can be engineered to comprise a cleavable linker so that a substituent of the phosphine is transferred to the azide, releasing an oxidized phosphine byproduct and producing a native amide bond in the final product. The selectivity of the reaction and its compatibility with aqueous environments provides for its application in vivo (e.g., on the cell surface or intracellularly) and in vitro (e.g., synthesis of peptides and other polymers, production of modified (e.g., labeled) amino acids).

  20. Chemoselective ligation

    DOEpatents

    Saxon, Eliana; Bertozzi, Carolyn

    2006-10-17

    The present invention features a chemoselective ligation reaction that can be carried out under physiological conditions. In general, the invention involves condensation of a specifically engineered phosphine, which can provide for formation of an amide bond between the two reactive partners resulting in a final product comprising a phosphine moiety, or which can be engineered to comprise a cleavable linker so that a substituent of the phosphine is transferred to the azide, releasing an oxidized phosphine byproduct and producing a native amide bond in the final product. The selectivity of the reaction and its compatibility with aqueous environments provides for its application in vivo (e.g., on the cell surface or intracellularly) and in vitro (e.g., synthesis of peptides and other polymers, production of modified (e.g., labeled) amino acids).

  1. Chemoselective ligation

    DOEpatents

    Saxon, Eliana; Bertozzi, Carolyn R.

    2011-04-12

    The present invention features a chemoselective ligation reaction that can be carried out under physiological conditions. In general, the invention involves condensation of a specifically engineered phosphine, which can provide for formation of an amide bond between the two reactive partners resulting in a final product comprising a phosphine moiety, or which can be engineered to comprise a cleavable linker so that a substituent of the phosphine is transferred to the azide, releasing an oxidized phosphine byproduct and producing a native amide bond in the final product. The selectivity of the reaction and its compatibility with aqueous environments provides for its application in vivo (e.g., on the cell surface or intracellularly) and in vitro (e.g., synthesis of peptides and other polymers, production of modified (e.g., labeled) amino acids).

  2. SOLVENT EXTRACTION PROCESS FOR URANIUM FROM CHLORIDE SOLUTIONS

    DOEpatents

    Blake, C.A. Jr.; Brown, K.B.; Horner, D.E.

    1960-05-24

    An improvement was made in a uranium extraction process wherein the organic extractant is a phosphine oxide. An aqueous solution containing phosphate ions or sulfate ions together with uranium is provided with a source of chloride ions during the extraction step. The presence of the chloride ions enables a phosphine oxide to extract uranium in the presence of strong uranium- complexing ions such as phosphate or sulfate ions.

  3. Catalyst-Switchable Regiocontrol in the Direct Arylation of Remote C–H Groups in Pyrazolo[1,5-a]pyrimidines**

    PubMed Central

    Bedford, Robin B; Durrant, Steven J; Montgomery, Michelle

    2015-01-01

    The regiodivergent palladium-catalyzed C–H arylation of pyrazolo[1,5-a]pyrimidine has been achieved, wherein the switch in regioselectivity between positions C3 and C7 is under complete catalyst control. A phosphine-containing palladium catalyst promotes the direct arylation at the most acidic position (C7), whereas a phosphine-free catalyst targets the most electron-rich position (C3). PMID:26095315

  4. Direct phosphonation of quinoxalin-2(1H)-ones under transition-metal-free conditions.

    PubMed

    Gao, Ming; Li, Yi; Xie, Lijuan; Chauvin, Remi; Cui, Xiuling

    2016-02-01

    A direct C-H bond phosphonation of quinoxalin-2(1H)-ones with H-phosphonates, H-phosphinates or H-phosphine oxides has been developed. A wide variety of heteroaryl phosphonates were obtained in up to 92% yield for 20 examples under transition-metal-free conditions. This protocol tolerates a broad scope of substrates and features practicality, high efficiency, environmental friendliness and atom economy. PMID:26779573

  5. Methods for suppressing isomerization of olefin metathesis products

    SciTech Connect

    Firth, Bruce E.; Kirk, Sharon E.; Gavaskar, Vasudeo S.

    2015-09-22

    A method for suppressing isomerization of an olefin metathesis product produced in a metathesis reaction includes adding an isomerization suppression agent to a mixture that includes the olefin metathesis product and residual metathesis catalyst from the metathesis reaction under conditions that are sufficient to passivate at least a portion of the residual metathesis catalyst. The isomerization suppression agent is phosphorous acid, a phosphorous acid ester, phosphinic acid, a phosphinic acid ester or combinations thereof. Methods of refining natural oils are described.

  6. The role of cocatalysts in the catalytic nitrogen reduction by sodium amalgam

    SciTech Connect

    Shilova, A.K.; Efimov, O.N.; Makhaev, V.D.; Shilov, A.E.

    1995-03-01

    Polyvinyl alcohol (PVA), phosphatidylcholine (PC), and organic phosphines are cocatalysts of the nitrogen reduction by sodium amalgam in which polynuclear molybdenum complexes serve as catalysts. PVA and PC are adsorbed on the amalgam surface and involve catalytic complexes, thus facilitating their contact with a reducing agent. Phosphines retard the decay of the catalytic centers in the course of the reaction, thus increasing the yield of the reduction products.

  7. Kit for preparing Tc (III)-99m myocardial imaging agents that are effective in humans

    SciTech Connect

    Deutsch, E.A.; Libson, K.F.

    1990-09-18

    This patent describes a myocardial imaging agent for humans that is a technetium (III) complex ligated in the planar positions by a tetradenate ligand such as (acac){sub 2}en and in the axial positions by an ether containing phosphine ligand such as tris(3-methoxy-1-propyl)-phosphine. The agent exhibits extremely rapid blood clearance after injection into a human and has a sufficiently high heart/liver and heart/lung ratios to provide effective myocardial images.

  8. Real-time bioluminescence imaging of glycans on live cells.

    PubMed

    Cohen, Allison S; Dubikovskaya, Elena A; Rush, Jason S; Bertozzi, Carolyn R

    2010-06-30

    Cell-surface glycans are attractive targets for molecule imaging due to their reflection of cellular processes associated with development and disease progression. In this paper, we describe the design, synthesis, and biological application of a new phosphine probe for real-time imaging of cell-surface glycans using bioluminescence. To accomplish this goal, we took advantage of the bioorthogonal chemical reporter technique. This strategy uses a two-step labeling procedure in which an unnatural sugar analogue containing a functional handle is (1) incorporated into sugar-bearing proteins via the cell's own biosynthetic machinery and then (2) detected with an exogenously added probe. We designed phosphine-luciferin reagent 1 to activate bioluminescence in response to Staudinger ligation with azide-labeled glycans. We chose to use a phosphine probe because, despite their slow reaction kinetics, they remain the best-performing reagents for tagging azidosugars in mice. Given the sensitivity and negligible background provided by bioluminescence imaging (BLI), we reasoned that 1 might be able to overcome some of the limitations encountered with fluorescent phosphine probes. In this work, we synthesized the first phosphine-luciferin probe for use in real-time BLI and demonstrated that azide-labeled cell-surface glycans can be imaged with 1 using concentrations as low as single digit nanomolar and times as little as 5 min, a feat that cannot be matched by any previous fluorescent phosphine probes. Even though we have only demonstrated its use in visualizing glycans, it can be envisioned that this probe could also be used for bioluminescence imaging of any azide-containing biomolecule, such as proteins and lipids, since azides have been previously incorporated into these molecules. The phosphine-luciferin probe is therefore poised for many applications in real-time imaging in cells and whole animals. These studies are currently in progress in our laboratory. PMID:20527879

  9. Synthesis of low color, atomic oxygen resistant polyimides

    NASA Technical Reports Server (NTRS)

    MacInnes, Dave

    1995-01-01

    The purpose of this project was to develop low color, atomic oxygen resistant polyimides for potential applications on spacecraft in low earth orbit. The material is needed in order to protect satellites and spacecraft from the gases and radiation found at those altitudes. Phosphorous containing polyimides have been shown to be especially resistant to corrosion and weight loss under oxygen plasma. Unfortunately the color of these phosphorous containing polyimides is still too high for them to be good heat insulators. While they are not as effective as teflon, the current material of choice. polyimides are much less dense than teflon and would be especially valuable if they could be made with low color. The approach taken was to synthesize a monomer which would contain the elements needed for giving the final polyimide its desired properties. In particular the monomer should incorporate phosphine or phosphine oxides and have bulky side groups to block any color forming charge transfer structures. The target molecule, 3,5-di-(trifluoromethylphenyl)-bis(3-aminophenyl) phosphine oxide, (containing both a phosphine oxide group and a bulky ditrifluoromethylphenyl group) was synthesized via three reactions in overall yield of 21 percent. In addition, a model compound, bis(3-phenylamine) phenyl phosphine oxide, was synthesized two different ways in order to establish the conditions for the nitration of phosphine oxides and their reduction to the amine. Finally, a trisubstituted phosphine oxide was synthesized. In all, seven phosphorus containing organic compounds were synthesized, purified and characterized. The model compound was reacted with oxydiphthalic anhydride to form a polyamic acid with inherent viscosity of 0.34. This material was cast into a film and heated, forming a normally colored fairly strong polyimide with a Tg of 240 C. The target compound was reacted with 6-fluorodiphthalic anhydride to give a polyamic acid with inherent viscosity of 0.19 and cast to give a heavily cracked colored film with a Tg of 230 C.

  10. Synthesis of low color, atomic oxygen resistant polyimides

    SciTech Connect

    Macinnes, D.

    1995-12-01

    The purpose of this project was to develop low color, atomic oxygen resistant polyimides for potential applications on spacecraft in low earth orbit. The material is needed in order to protect satellites and spacecraft from the gases and radiation found at those altitudes. Phosphorous containing polyimides have been shown to be especially resistant to corrosion and weight loss under oxygen plasma. Unfortunately the color of these phosphorous containing polyimides is still too high for them to be good heat insulators. While they are not as effective as teflon, the current material of choice. polyimides are much less dense than teflon and would be especially valuable if they could be made with low color. The approach taken was to synthesize a monomer which would contain the elements needed for giving the final polyimide its desired properties. In particular the monomer should incorporate phosphine or phosphine oxides and have bulky side groups to block any color forming charge transfer structures. The target molecule, 3, 5-di-(trifluoromethylphenyl)-bis(3-aminophenyl) phosphine oxide, (containing both a phosphine oxide group and a bulky ditrifluoromethylphenyl group) was synthesized via three reactions in overall yield of 21 percent. In addition, a model compound, bis(3-phenylamine) phenyl phosphine oxide, was synthesized two different ways in order to establish the conditions for the nitration of phosphine oxides and their reduction to the amine. Finally, a trisubstituted phosphine oxide was synthesized. In all, seven phosphorus containing organic compounds were synthesized, purified and characterized. The model compound was reacted with oxydiphthalic anhydride to form a polyamic acid with inherent viscosity of 0.34. This material was cast into a film and heated, forming a normally colored fairly strong polyimide with a Tg of 240 C.

  11. Solid-phase synthesis of chiral 3,4-diazaphospholanes and their application to catalytic asymmetric allylic alkylation

    PubMed Central

    Landis, Clark R.; Clark, Thomas P.

    2004-01-01

    Functionalized chiral diazaphospholanes ligate to a variety of transition metals, yielding chiral, catalytically active, metal complexes. Previous work has established that amino acid derivatization of the carboxyl groups of (R,R)-N,N′-phthaloyl-2,3-(2-carboxyphenyl)-phenyl-3,4-diazaphospholane (1) yields phosphines that are excellent ligands for palladium-catalyzed asymmetric allylic alkylation reactions. Alanine functionalization is particularly effective for allylic alkylation of 1,3-dimethylallyl acetate. Standard Merrifield resins and amino acid coupling methods are used to synthesize the bead-attached phosphine having the topology bead-linker-lAla-(R,R)-1-lAla-OMe, as a 1:1 mixture of linkage isomers. Use of this supported phosphine in Pd-catalyzed asymmetric allylic alkylation yields 92% enantiomeric excess, matching prior solution-phase results. A 20-member collection of amino acid-functionalized phosphines on beads with the topology bead-linker-AA2-AA1-1-AA1-AA2 was synthesized by using parallel solid-state methods and screened for efficacy in allylic alkylation. Resulting enantioselectivities indicate that the AA1 position has the strongest effect on the reaction. Catalyst activities can vary widely with the nature of the phosphine ligand and the reaction conditions. Meaningful analysis of intrinsic catalytic activities awaits identification of the structure and abundance of the active catalyst. PMID:14985503

  12. Transition metal chemistry of main group hydrazides. 16. (Phosphanyl)hydrazines R{sub 2}PN(Me)N(Me)PR{sub 2} as a novel class of chelating bis(phosphines). Synthesis, coordination chemistry, and X-ray structures of cis-[PdCl{sub 2}[(p-BrC{sub 6}H{sub 4}O){sub 2}PN-(Me)N(Me)P(OC{sub 6}H{sub 4}Br-p){sub 2}

    SciTech Connect

    Reedy, V.S.; Katti, K.V.; Barnes, C.L.

    1995-10-25

    The alkoxy- and aryloxy-functionalized bis(phosphanyl)hydrazines of the type (OR){sub 2}PN(Me)N(Me)P(OR){sub 2} were obtained from the reactions of the corresponding alcohols and phenols with Cl{sub 2}PN(Me)N(Me)PCl{sub 2} in the presence of Et{sub 3}N. Interaction of these ligands with group 6 metal carbonyl precursors M(CO){sub 4}(NHC{sub 5}H{sub 10}){sub 2}(M=Mo, W) gave the tetracarbonyl complexes of the type cis-[M(CO){sub 4}(OR){sub 2}PN(Me)N(Me)P(OR){sub 2}]. The reactions of the alkoxy and aryloxy-functionalized bis(phosphanyl)hydrazines with Pd(PhCN){sub 2}(Cl){sub 2} or with Pt(COD)Cl{sub 2} resulted in the formation of the complexes of the type cis[MCl{sub 2}(OR){sub 2}PN(Me)N(Me)P(OR){sub 2}]. The ligands are bound cis to the metal center(s) in all the complexes. The structures of all the complexes have been established by combination of spectroscopic and elemental analysis. As representative examples, the authors have determined the structures of cis-[W(CO){sub 4}[(OPh){sub 2}PN(Me)N(Me)P(OPh){sub 2}

  13. Preparation of tetraalkyl phosphine complexes of the f-block metals. Crystal structure of Th(CH/sub 2/Ph)/sub 4/(Me/sub 2/PCH/sub 2/CH/sub 2/PMe/sub 2/) and U(CH/sub 2/Ph)/sub 3/Me(Me/sub 2/PCH/sub 2/CH/sub 2/PMe/sub 2/)

    SciTech Connect

    Edwards, P.G.; Andersen, R.A.; Zalkin, A.

    1984-01-01

    Reaction of 4 molar equiv of PhCH/sub 2/Li with MCl/sub 4/(Me/sub 2/PCH/sub 2/CH/sub 2/PMe/sub 2/)/sub 2/ gives M(CH/sub 2/Ph)/sub 4/ (Me/sub 2/PCH/sub 2/CH/sub 2/PMe/sub 2/), where M is Th or U. Reaction of a mixture of 3 molar equiv of PhCH/sub 2/Li and 1 molar equiv of MeLi with MCl/sub 4/(Me/sub 2/PCH/sub 2/CH/sub 2/PMe/sub 2/)/sub 2/ gives the unsymmetrical alkyls M(CH/sub 2/Ph)/sub 3/Me(Me/sub 2/PCH/sub 2/CH/sub 2/PMe/sub 2/), where M is Th or U. The molecular structure of Th(CH/sub 2/C/sub 6/H/sub 5/)/sub 4/(Me/sub 2/PCH/sub 2/CH/sub 2/PMe/sub 2/) and U(CH/sub 2/C/sub 6/H/sub 5/)/sub 3/Me(Me/sub 2/PCH/sub 2/CH/sub 2/PMe/sub 2/) were determined by single-crystal X-ray diffraction methods, and the crystal parameters are reported. In the Th complex there are two independent molecules in the unit cell. The Th atoms are each bonded to four benzyl groups and to two phosphorus atoms from the bis(dimethylphosphino)ethane ligand; the average Th-C distance is 2.55 (2) A, and the average Th-P distance is 3.17 (3) A. In the U complex the uranium atom is bonded to a methyl group, three benzyl groups, and the two phosphorus atoms of the bis(dimethylphosphino)ethane ligand. The U-C(methyl) distance is 2.41 (1) A; the average U-C(benzyl) distance is 2.50 (4) A. 23 references, 3 figures, 7 tables.

  14. Heterogeneous catalyst for the production of acetic anhydride from methyl acetate

    DOEpatents

    Ramprasad, Dorai; Waller, Francis Joseph

    1999-01-01

    This invention relates to a process for producing acetic anhydride by the reaction of methyl acetate, carbon monoxide, and hydrogen at elevated temperatures and pressures in the presence of an alkyl halide and a heterogeneous, bifunctional catalyst that contains an insoluble polymer having pendant quaternized phosphine groups, some of which phosphine groups are ionically bonded to anionic Group VIII metal complexes, the remainder of the phosphine groups being bonded to iodide. In contrast to prior art processes, no accelerator (promoter) is necessary to achieve the catalytic reaction and the products are easily separated from the catalyst by filtration. The catalyst can be recycled for consecutive runs without loss in activity. Bifunctional catalysts for use in carbonylating dimethyl ether are also provided.

  15. Method for separating metal chelates from other materials based on solubilities in supercritical fluids

    DOEpatents

    Wai, Chien M.; Smart, Neil G.; Phelps, Cindy

    2001-01-01

    A method for separating a desired metal or metalloi from impurities using a supercritical extraction process based on solubility differences between the components, as well as the ability to vary the solvent power of the supercritical fluid, is described. The use of adduct-forming agents, such as phosphorous-containing ligands, to separate metal or metalloid chelates in such processes is further disclosed. In preferred embodiments, the extraction solvent is supercritical carbon dioxide and the chelating agent is selected from the group consisting of .beta.-diketones; phosphine oxides, such as trialkylphosphine oxides, triarylphosphine oxides and alkylarylphosphine oxides; phosphinic acids; carboxylic acids; phosphates, such as trialkylphosphates, triarylphosphates and alkylarylphosphates; crown ethers; dithiocarbamates; phosphine sulfides; phosphorothioic acids; thiophosphinic acids; halogenated analogs of these chelating agents; and mixtures of these chelating agents. In especially preferred embodiments, at least one of the chelating agents is fluorinated.

  16. High Efficiency InP Solar Cells from Low Toxicity Tertiarybutylphosphine

    NASA Technical Reports Server (NTRS)

    Hoffman, Richard W., Jr.; Fatemi, Navid S.; Wilt, David M.; Jenkins, Phillip P.; Brinker, David J.; Scheiman, David A.

    1994-01-01

    Large scale manufacture of phosphide based semiconductor devices by organo-metallic vapor phase epitaxy (OMVPE) typically requires the use of highly toxic phosphine. Advancements in phosphine substitutes have identified tertiarybutylphosphine (TBP) as an excellent precursor for OMVPE of InP. High quality undoped and doped InP films were grown using TBP and trimethylindium. Impurity doped InP films were achieved utilizing diethylzinc and silane for p and n type respectively. 16 percent efficient solar cells under air mass zero, one sun intensity were demonstrated with Voc of 871 mV and fill factor of 82.6 percent. It was shown that TBP could replace phosphine, without adversely affecting device quality, in OMVPE deposition of InP thus significantly reducing toxic gas exposure risk.

  17. Synthesis and characterization of poly(ether ketone)s containing phosphorus and fluorine

    SciTech Connect

    Youngman, P.W.; Fitch, J.W.; Cassidy, P.E.

    1996-10-01

    Because of the excellent properties exhibited by fluorinated poly(ether ketone)s, modifications were sought to further improve this polymer toward atomic oxygen resistance. For this purpose a phosphorous-containing monomer [bis(4-fluorophenyl)phenyl phosphine oxide] was synthesized and incorporated into a poly(ether ketone) backbone by reaction with 2,2-bis[4-(4-fluorobenzoyl)phenyl]hexafluoropropane in varying proportions with bisphenol AF to produce polymers with different amounts of the phosphine oxide repeating unit in the backbone. Colorless, film-forming materials were produced with a slight increase in Tg due to the phosphine oxide function. The incorporation of this moiety also resulted in a very small increase in the dielectric constant and an improved resistance to atomic oxygen ablation.

  18. High efficiency InP solar cells from low toxicity tertiarybutylphosphine and trimethylindium by OMVPE

    SciTech Connect

    Hoffman, R.W. Jr.; Fatemi, N.S.; Wilt, D.M.; Brinker, D.J.; Jenkins, P.P.; Scheiman, D.A.

    1994-12-31

    Large scale manufacture of phosphide based compound semiconductor devices by organo-metallic vapor phase epitaxy (OMVPE) typically requires the use of highly toxic phosphine. Advancements in phosphine substitutes have identified tertiarybutylphosphine (TBP) as an excellent precursor for OMVPE of InP. High quality undoped and doped InP films were grown using TBP and trimethylindium. Impurity doped InP films were achieved utilizing diethylzinc and silane for p-type and n-type respectively. 16% efficient solar cells under air mass zero, one sun intensity were demonstrated with V{sub oc} of 871 mV and fill factor of 82.6%. It was shown that TBP could replace phosphine, without adversely affecting device quality, in OMVPE deposition of InP thus significantly reducing toxic gas exposure risk.

  19. Heterogeneous catalyst for the production of acetic anhydride from methyl acetate

    DOEpatents

    Ramprasad, D.; Waller, F.J.

    1999-04-06

    This invention relates to a process for producing acetic anhydride by the reaction of methyl acetate, carbon monoxide, and hydrogen at elevated temperatures and pressures in the presence of an alkyl halide and a heterogeneous, bifunctional catalyst that contains an insoluble polymer having pendant quaternized phosphine groups, some of which phosphine groups are ionically bonded to anionic Group VIII metal complexes, the remainder of the phosphine groups being bonded to iodide. In contrast to prior art processes, no accelerator (promoter) is necessary to achieve the catalytic reaction and the products are easily separated from the catalyst by filtration. The catalyst can be recycled for consecutive runs without loss in activity. Bifunctional catalysts for use in carbonylating dimethyl ether are also provided.

  20. A computational study on the insertion of CO2 into (PSiP)palladium allyl σ-bond.

    PubMed

    Wang, Qin; Guo, Cai-Hong; Ren, Ying; Wu, Hai-Shun

    2015-05-01

    The insertion of CO2 into the (PSiP)palladium-allyl bond has been investigated using DFT. Three possible modes of CO2 insertion into (PSiP)Pd-allyl bond have been calculated, that is, direct 1.2-insertion mode, metallo-ene mode, and SE2 mode. The metallo-ene mode is the most favorable via the six-membered ring transition state. The results of calculations are consistent with the regioselectivity observed experimentally. The steric and electronic effects of different phosphine substituents have been evaluated by ONIOM and energy decomposition analysis (EDA) methods. For the phosphine substituents P(i-Pr)2 and PPh2, the contribution of electronic effect is greater than that of steric effect for the CO2 insertion into (PSiP)Pd-allyl bond; while for the phosphine substituent PMe2, the contribution of steric effect is slightly greater than that of electronic effect. PMID:25893517

  1. [Stereocontrolled synthesis of phosphinyl dipeptide isosteres using an asymmetric center at the phosphorus atom].

    PubMed

    Yamagishi, Takehiro

    2014-01-01

    Phosphinyl dipeptide isosteres (PDIs) are important compounds for the development of potent and selective inhibitors of various aspartic proteases and Zn metalloproteases. The stereochemistry of PDIs affects their biological activity. PDIs were prepared successfully using the concept of asymmetric induction from the chiral phosphorus atom of the phosphinate moiety to the neighboring carbon atom. This methodology involves diastereoselective ?-alkylation and ?'-alkylation of P-chiral phosphinate derivatives, prepared through lipase-catalyzed kinetic resolution, which produces Phe-Ala type and Pro-Phe type PDIs. The synthesis of Leu-Pro type PDIs in a protected form was achieved through a cross-coupling reaction of stereodefined ?-amino-H-phosphinate with alkenyl triflate, followed by diastereoselective hydrogenation of the alkene moiety. PMID:25174361

  2. Statistical Analysis of Near-Infrared Spectra of Saturn and Rings Pre-Cassini

    NASA Astrophysics Data System (ADS)

    Jezewski, Sean

    2007-10-01

    Medium resolution near-infrared spectra of Saturn were acquired at NASA/InfraRed Telescope Facility (IRTF) with Spex prior to the arrival of Cassini at Saturn. The data were acquired in a cross-dispersed mode, with a slit of 15 x 0.5 arc sec, with a resolution comparable to Cassini/VIMS data. Phosphine is a species of interest, as it is only present when dredged from the deep atmosphere. The temporal variation of the global distribution of various chemical species, such as phosphine, is mapped by utilizing an IDL-based suite of tools designed for post-processing of the extracted spectra. These tools were developed for the analysis of the recent Jovian North Temperate Belt (NTBs) disturbance (Yanamandra-Fisher et al., DPS 2007). The pre-Cassini spectra of Saturn provide a valuable window to trace the distribution of phosphine in the southern hemisphere and its subsequent global distribution. This analysis will map the temporal evolution of various species, especially phosphine, as function of latitude and longitude from 2001 to 2004. Initial results indicate variability of phosphine increasing from the southern pole towards the equator and increasing in time towards southern solstice in late 2002/early 2003. A principle component analysis (PCA), will be performed on the spatial maps to illustrate any underlying spatial relations between the various species and physical models. The results of this study will extend the results of Cassini/VIMS, to understand the seasonal variations of phosphine. This research was performed by SWJ at the Jet Propulsion Laboratory under the auspices of an USRP summer internship.

  3. Coordination Chemistry of Cyclic Disilylated Germylenes and Stannylenes with Group 11 Metals

    PubMed Central

    2014-01-01

    Reactions of Et3P adducts of bissilylated germylenes and stannylenes with gold, silver, and copper cyanides led to cyanogermyl or -stannyl complexes of the respective metals. In the course of the reaction the phosphine moved to the metal, while the cyanide migrated to the low-coordinate group 14 element. The respective gold complexes were found to be monomeric, whereas the silver and copper complexes exhibited a tendency to dimerize in the solid state. Attempts to abstract the phosphine ligand with B(C6F5)3 led only to the formation of adducts with the borane coordinating to the cyanide nitrogen atom. PMID:25550678

  4. Electrochemical reduction of CO{sub 2} catalyzed by small organophosphine dendrimers containing palladium

    SciTech Connect

    Miedaner, A.; Curtis, C.J.; DuBois, D.L.; Barkley, R.M.

    1994-11-23

    The sequential addition of diethyl vinylphosphonate to primary phosphines followed by reduction with lithium aluminum hydride can be used to synthesize small dendrimers containing up to 15 phosphorus atoms. A second approach uses the addition of bis((diethylphosphino)ethyl)phosphine to tetravinylsilane to produce a dendrimer containing 12 phosphorus atoms. The connectivities of these ligands are established unambiguously by {sup 31}P NMR spectroscopy. These dendrimers react with [Pd(CH{sub 3}CN){sub 4}](BF{sub 4}){sub 2} to produce metalated dendrimers which catalyze the electrochemical reduction of CO{sub 2} to CO. Relationships between catalytic properties and dendrimer structure are discussed.

  5. Phosphorus-containing imide resins

    NASA Technical Reports Server (NTRS)

    Varma, I. K.; Fohlen, G. M.; Parker, J. A. (Inventor)

    1983-01-01

    Bis- and tris-imides derived from tris (m-aminophenyl) phosphine oxides by reaction with maleic anhydride or its derivatives, and addition polymers of such imides, including a variant in which a mono-imide is condensed with a dianhydride and the product is treated with a further quantity of maleic anhydride. Such monomers or their oligomes may be used to impregnate fibers and fabrics which when cured, are flame resistant. Also an improved method of producing tris (m-aminophenyl) phosphine oxides from the nitro analogues by reduction with hydrazine hydrate using palladized charcoal or Raney nickel as the catalyst is described.

  6. Phosphorus-containing imide resins

    NASA Technical Reports Server (NTRS)

    Varma, I. K.; Fohlen, G. M.; Parker, J. A. (Inventor)

    1985-01-01

    Cured polymers of bis and tris-imides derived from tris(m-aminophenyl) phosphine oxides by reaction with maleic anhydride or its derivatives, and addition polymers of such imides, including a variant in which a monoimide is condensed with a dianhydride and the product is treated with a further quantity of maleic anhydride prior to curing are disclosed and claimed. Such polymers are flame resistant. Also disclosed are an improved method of producing tris(m-aminophenyl) phosphine oxides from the nitro analogues by reduction with hydrazine hydrate using palladized charcoal or Raney nickel as the catalyst and fiber reinforced cured resin composites.

  7. Zinc Phosphide Poisoning

    PubMed Central

    Doğan, Erdal; Güzel, Abdulmenap; Çiftçi, Taner; Aycan, İlker; Çetin, Bedri; Kavak, Gönül Ölmez

    2014-01-01

    Zinc phosphide has been used widely as a rodenticide. Upon ingestion, it gets converted to phosphine gas in the body, which is subsequently absorbed into the bloodstream through the stomach and the intestines and gets captured by the liver and the lungs. Phosphine gas produces various metabolic and nonmetabolic toxic effects. Clinical symptoms are circulatory collapse, hypotension, shock symptoms, myocarditis, pericarditis, acute pulmonary edema, and congestive heart failure. In this case presentation, we aim to present the intensive care process and treatment resistance of a patient who ingested zinc phosphide for suicide purposes. PMID:25101186

  8. An electrochemical study for corrosion inhibition of iron by some organic phosphonium chloride derivatives in acid media

    NASA Astrophysics Data System (ADS)

    Khaled, K. F.

    2004-05-01

    The inhibiting action of (chloromethyl) triphenyl phosphonium chloride (CTP), tetraphenyl phosphonum chloride (TP), triphenyl phosphine oxide (TPO), triphenyl (phenylmethyl) phosphonium chloride (TPM) and triphenyl phosphine (TPP) on the corrosion of iron in 1 M HCl solution was studied using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). Experimental results revealed that CTP, TP, TPO, and TPM act as inhibitors for iron in acid environments, while TPP is an accelerator. These compounds are mixed-type inhibitors and the inhibition efficiency increased with increasing concentrations. Equivalent circuits of the investigated systems are suggested.

  9. Photocatalytic CO2 Reduction Using Cu(I) Photosensitizers with a Fe(II) Catalyst.

    PubMed

    Takeda, Hiroyuki; Ohashi, Kenji; Sekine, Akiko; Ishitani, Osamu

    2016-04-01

    Photocatalytic systems developed from complexes with only abundant metals, i.e., Cu(I)(dmp)(P)2(+) (dmp =2,9-dimethyl-1,10-phenanthroline; P = phosphine ligand) as a redox photosensitizer and Fe(II)(dmp)2(NCS)2 as a catalyst, produced CO as the main product by visible light irradiation. The best photocatalysis was obtained using a Cu(I) complex with a tetradentate dmp ligand tethering two phosphine groups, where the turnover number and quantum yield of CO formation were 273 and 6.7%, respectively. PMID:27015323

  10. Multiphosphine-Oxide Hosts for Ultralow-Voltage-Driven True-Blue Thermally Activated Delayed Fluorescence Diodes with External Quantum Efficiency beyond 20.

    PubMed

    Zhang, Jing; Ding, Dongxue; Wei, Ying; Han, Fuquan; Xu, Hui; Huang, Wei

    2016-01-20

    Highly efficient low-voltage-driven -true-blue thermally activated -delayed fluorescence diodes are realized through employing a tri-phosphine oxide host (2,2',4-tris(di(phenyl) -phosphoryl)-diphenylether (DPETPO)) with a record external quantum efficiency of 23.0% and the lowest onset voltage of 2.8 V to date. PMID:26588189

  11. Difluorotris(perfluoralkyl)phosphoranes

    SciTech Connect

    Semenii, V.Ya.; Stepanov, V.A.; Ignat'ev, N.V.; Furin, G.G.; Yagupol'skii, L.M.

    1986-05-20

    By the electrochemical fluorination of trialkylphosphine oxides difluorotris(perfluoroalkyl)phosphoranes were obtained in yields which fell as the alkyl chain was lengthened. In the reactions of difluorotris(perfluoroalkyl)phosphoranes with hexamethyldisiloxane the corresponding phosphine oxides are formed, and in an HF medium these are converted back into the difluorophosphoranes.

  12. Aggregation-induced emission of a novel conjugated phosphonium salt and its application in mitochondrial imaging

    NASA Astrophysics Data System (ADS)

    Chen, Wen-dan; Zhang, Da-wei; Gong, Wei-tao; Lin, Yuan; Ning, Gui-ling

    2013-06-01

    A new conjugated phosphonium salt TPP was synthesized readily from phosphine-triggered ring-opening of 2,4,5-triphenylpyrylium salt. In aqueous solution, it exhibited interesting AIEE properties and self-assembled into fluorescent nanoparticles, which can be used as a fluorescence probe to image mitochondria in cells.

  13. Dried Fruits and Nuts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Current control of postharvest insect pests of dried fruits and tree nuts relies heavily on fumigants such as methyl bromide or phosphine. There is mounting pressure against the general use of chemical fumigants due to atmospheric emissions, safety or health concerns, and an increased interest in or...

  14. [Ir(P-OP)]-catalyzed asymmetric hydrogenation of diversely substituted C═N-containing heterocycles.

    PubMed

    Núñez-Rico, José Luis; Vidal-Ferran, Anton

    2013-04-19

    Iridium(I) complexes of enantiomerically pure phosphine-phosphite ligands ([Ir(Cl)(cod)(P-OP)]) efficiently catalyze the enantioselective hydrogenation of diverse C═N-containing heterocyclic compounds (benzoxazines, benzoxazinones, benzothiazinones, and quinoxalinones; 25 examples, up to 99% ee). A substrate-to-catalyst ratio as high as 2000:1 was reached. PMID:23573959

  15. Enantioselective synthesis of (–)-chloramphenicol via silver-catalysed asymmetric isocyanoacetate aldol reaction† †Electronic supplementary information (ESI) available: Experimental procedures, characterisation data, copies of 1H and 13C NMR spectra, and HPLC traces. See DOI: 10.1039/c5ob02141c Click here for additional data file.

    PubMed Central

    Franchino, Allegra; Jakubec, Pavol

    2015-01-01

    The highly enantio- and diastereoselective aldol reaction of isocyanoacetates catalysed by Ag2O and cinchona-derived amino phosphines applied to the synthesis of (–)- and (+)-chloramphenicol is described. The concise synthesis showcases the utility of this catalytic asymmetric methodology for the preparation of bioactive compounds possessing α-amino-β-hydroxy motifs. PMID:26510469

  16. Enantioselective synthesis of (-)-chloramphenicol via silver-catalysed asymmetric isocyanoacetate aldol reaction.

    PubMed

    Franchino, Allegra; Jakubec, Pavol; Dixon, Darren J

    2016-01-01

    The highly enantio- and diastereoselective aldol reaction of isocyanoacetates catalysed by Ag2O and cinchona-derived amino phosphines applied to the synthesis of (-)- and (+)-chloramphenicol is described. The concise synthesis showcases the utility of this catalytic asymmetric methodology for the preparation of bioactive compounds possessing α-amino-β-hydroxy motifs. PMID:26510469

  17. The 1982 NASA/ASEE summer faculty fellowship research program, abstracts of research projects, 1st and 2nd-year fellows

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Phosphine photolysis in Jupiter's atmosphere is discussed in relation to organic chemical evolution. Workload in AFTI F-16 test flights, infrared observations of M17, and the relation between rock and vegetation types are presented. Orbiter transfer vehicle aerothermodynamics simulation problems are also discussed.

  18. 40 CFR 721.10370 - Phosphonic acid, p-octyl-, lanthanum (3+) salt (2:1).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Phosphonic acid, p-octyl-, lanthanum... New Uses for Specific Chemical Substances § 721.10370 Phosphonic acid, p-octyl-, lanthanum (3+) salt... substance identified as phosphinic acid, p-octyl-, lanthanum (3+) salt (2:1) (PMN P-10-99; CAS No....

  19. 40 CFR 721.10370 - Phosphonic acid, p-octyl-, lanthanum (3+) salt (2:1).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Phosphonic acid, p-octyl-, lanthanum... New Uses for Specific Chemical Substances § 721.10370 Phosphonic acid, p-octyl-, lanthanum (3+) salt... substance identified as phosphinic acid, p-octyl-, lanthanum (3+) salt (2:1) (PMN P-10-99; CAS No....

  20. 40 CFR 721.10370 - Phosphonic acid, p-octyl-, lanthanum (3+) salt (2:1).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Phosphonic acid, p-octyl-, lanthanum... New Uses for Specific Chemical Substances § 721.10370 Phosphonic acid, p-octyl-, lanthanum (3+) salt... substance identified as phosphinic acid, p-octyl-, lanthanum (3+) salt (2:1) (PMN P-10-99; CAS No....