Science.gov

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. 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.

  3. 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

  4. HUMAN GENOTOXICITY: PESTICIDE APPLICANTS AND PHOSPHINE

    EPA Science Inventory

    Fumigant applicators who, 6 weeks to 3 months earlier, were exposed to phosphine, a common grain fumigant, or to phosphine and other pesticides had significantly increased stable chromosome rearrangements, primarily translocations in G-banded lymphocytes. ess stable aberrations i...

  5. 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 MoritaBaylisHillman (MBH) acetates, carbonates, and ketenes with activated alkenes and imines, allylic substitutions of MBH acetates and carbonates, Michael additions, ?-umpolung additions, and acylations of alcohols. PMID:25246969

  6. Reductive Catenation of Phosphine Antimony Complexes.

    PubMed

    Chitnis, Saurabh S; Burford, Neil; Weigand, Jan J; McDonald, Robert

    2015-06-26

    Reactions of triarylphosphines with fluoroantimony(III) triflates give phosphine antimony(III) complexes, which undergo spontaneous reductive elimination of fluorophosphonium cations. The resulting phosphine antimony(I) complexes catenate to give the first examples of cationic antimony bicyclic compounds, [(R3P)4Sb6](4+), featuring a bicyclo[3.1.0]hexastibine framework stabilized by four phosphine ligands. The unprecedented 14-electron redox process illustrates the generality of the reductive catenation method. PMID:26037929

  7. 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.

  8. 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.

  9. 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...

  10. Phosphine from rocks: mechanically driven phosphate reduction?

    PubMed

    Glindemann, Dietmar; Edwards, Marc; Morgenstern, Peter

    2005-11-01

    Natural rock and mineral samples released trace amounts of phosphine during dissolution in mineral acid. An order of magnitude more phosphine (average 1982 ng PH3 kg rock and maximum 6673 ng PH3/kg rock) is released from pulverized rock samples (basalt, gneiss, granite, clay, quartzitic pebbles, or marble). Phosphine was correlated to hardness and mechanical pulverization energy of the rocks. The yield of PH3 ranged from 0 to 0.01% of the total P content of the dissolved rock. Strong circumstantial evidence was gathered for reduction of phosphate in the rock via mechanochemical or "tribochemical" weathering at quartz and calcite/marble inclusions. Artificial reproduction of this mechanism by rubbing quartz rods coated with apatite-phosphate to the point of visible triboluminescence, led to detection of more than 70 000 ng/kg PH3 in the apatite. This reaction pathway may be considered a mechano-chemical analogue of phosphate reduction from lightning or electrical discharges and may contribute to phosphine production via tectonic forces and processing of rocks. PMID:16294866

  11. Palladium-Catalyzed ?-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 (5191%). PMID:24295336

  12. Homo- and Heteropolynuclear Clusters of Phosphine Triphenolates.

    PubMed

    Liang, Lan-Chang; Chou, Kuan-Wei; Su, Wei-Jia; Chen, Han-Sheng; Hsu, Yu-Lin

    2015-12-01

    The synthesis and structural characterization of a series of homo- and heteropolynuclear clusters constructed with a potentially tetradentate phosphine triphenolate ligand are presented. Treatment of tris(3,5-di-tert-butyl-2-hydroxyphenyl)phosphine (H3[O3P]) with 3 equiv of nBuLi in diethyl ether at -35 C affords hexanuclear Li6[O3P]2(OEt2)2 (1) as colorless crystals. In situ lithiation of H3[O3P] with 3 equiv of nBuLi in THF at -35 C followed by metathetical reactions with MnCl2 or NiCl2(DME) gives crystals of forest green pentanuclear MnLi4[O3P]2(THF)3 (2) or dark brown tetranuclear Ni2Li2[O3P]2(THF)2 (3), respectively. Alkane elimination of ZnR2 (R = Me, Et) with H3[O3P] in THF at 25 C generates high yields of colorless crystalline trinuclear Zn3[O3P]2(THF)2 (4). The cluster structures of 1-4 were all determined by single crystal X-ray diffraction studies. These molecules represent the first examples of metal complexes supported by phosphine triphenolate derivatives. The cluster 2 contains a paramagnetic core of high spin Mn(II) (S = 5/2) as indicated by solution and solid state magnetic susceptibility measurements. PMID:26587884

  13. 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 ureaH2O2, 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

  14. 40 CFR 180.225 - Phosphine; tolerances for residues.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Phosphine; tolerances for residues. 180.225 Section 180.225 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Specific Tolerances § 180.225 Phosphine; tolerances for residues....

  15. 40 CFR 180.225 - Phosphine; tolerances for residues.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Phosphine; tolerances for residues...) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Specific Tolerances § 180.225 Phosphine; tolerances for residues. (a) General. (1) Tolerances are established for...

  16. 7 CFR 305.7 - Phosphine treatment schedules.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 5 2010-01-01 2010-01-01 false Phosphine treatment schedules. 305.7 Section 305.7 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE PHYTOSANITARY TREATMENTS Chemical Treatments 305.7 Phosphine treatment schedules. Treatmentschedule...

  17. Phosphine-induced physiological and biochemical responses in rice seedlings.

    PubMed

    Mi, Lina; Niu, Xiaojun; Lu, Meiqing; Ma, Jinling; Wu, Jiandong; Zhou, Xingqiu

    2014-04-01

    Paddy fields have been demonstrated to be one of the major resources of atmospheric phosphine and may have both positive and negative effects on rice plants. To elucidate the physiological and biochemical responses of rice plants to phosphine, rice seedlings (30 d old) were selected as a model plant and were treated with different concentrations of phosphine (0, 1.4, 4.2, and 7.0 mg m(-3)). Antioxidant enzymes, including superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), and lipid peroxidation measured via malondialdehyde (MDA) were determined as indicators of the physiological and biochemical responses of the rice seedlings to phosphine exposure. Increasing concentrations of phosphine treatment enhanced the activity of SOD, POD, and CAT. In addition, the MDA content increased with increasing concentrations of phosphine. These results suggested that antioxidant enzymes played important roles in protecting rice seedlings from ROS damage. Moreover, rice seedlings were able to cope with the oxidative stress induced by low concentrations of phosphine via an increase in antioxidant enzymatic activities. However, oxidative stress may not fully be prevented when the plants were exposed to higher concentrations of phosphine. PMID:24405968

  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 production potential of various wastewater and sewage sludge sources

    SciTech Connect

    Devai, I.; DeLaune, R.D.; Patrick, W.H. Jr.; Devai, G.; Czegeny, I.

    1999-05-01

    A laboratory incubation procedure followed by gas chromatographic detection was used to measure phosphine production potential in representative wastewater and sewage sludge sources. Phosphine production potential was determined by measuring the rate of phosphine formation in samples incubated under laboratory conditions over a seven day period when both electron donors and the targeted electron acceptor were not limiting factors. Results of their experiments showed that except the primary effluent and secondary effluent wastewater samples all other samples studied (influent wastewater, various type of sludge and sediment sources) produced phosphine. The minimum phosphine production potential value (0.39 pg/ml wastewater/day) was measured in composite influent wastewater samples while the maximum (268 pg/g wet sludge/day) was measured in sediment samples collected from an open-air sewage treatment plant.

  20. Phosphine in paddy fields and the effects of environmental factors.

    PubMed

    Niu, Xiaojun; Wei, Aishu; Li, Yadong; Mi, Lina; Yang, Zhiquan; Song, Xiaofei

    2013-11-01

    Ambient levels of phosphine (PH3) in the air, phosphine emission fluxes from paddy fields and rice plants, and the distribution of matrix-bound phosphine (MBP) in paddy soils were investigated throughout the growing stages of rice. The relationships between MBP and environmental factors were analyzed to identify the principal factors determining the distribution of MBP. The phosphine ambient levels ranged from 2.3680.6060 ng m(-3) to 24.836.529 ng m(-3) and averaged 14.254.547 ng m(-3). The highest phosphine emission flux was 22.543.897 ng (m(2)h)(-1), the lowest flux was 7.644.83 ng (m(2)h)(-1), and the average flux was 14.174.977 ng (m(2)h)(-1). Rice plants transport a significant portion of the phosphine emitted from the paddy fields. The highest contribution rate of rice plants to the phosphine emission fluxes reached 73.73% and the average contribution was 43.00%. The average MBP content of 111.6 ng kg(-1)fluctuated significantly in different stages of rice growth and initially increased then decreased with increasing depth. The peak MBP content in each growth stage occurred approximately 10 cm under the surface of paddy soils. Pearson correlation analyses and stepwise multiple regression analysis showed that soil temperature (Ts), acid phosphatase (ACP) and total phosphorus (TP) were the principal environmental factors, with correlative rankings of Ts>ACP>TP. PMID:23876504

  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 Taniguchis azocarboxylate catalytic system provided the first fully catalytic Mitsunobu reaction. PMID:26347115

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

    PubMed

    Buonomo, Joseph A; Aldrich, Courtney C

    2015-10-26

    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

  3. 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.

  4. 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.

  5. Tentative detection of phosphine in IRC +10216

    NASA Astrophysics Data System (ADS)

    Agndez, M.; Cernicharo, J.; Pardo, J. R.; Gulin, M.; Phillips, T. G.

    2008-07-01

    Aims: The JK = 10-00 rotational transition of phosphine (PH3) at 267 GHz has been tentatively identified with a T_MB ~ 40 mK spectral line observed with the IRAM 30-m telescope in the C-star envelope IRC +10216. Methods: A radiative transfer model was used to fit the observed line profile. Results: The derived PH3 abundance relative to H2 is 6 10-9, although it may have a large uncertainty due to the lack of knowledge about the spatial distribution of this species. If our identification is correct, it implies that PH3 has a similar abundance to what is reported for HCP in this source and that these two molecules (HCP and PH3) together take up about 5% of phosphorus in IRC +10216. The abundance of PH3, like that of other hydrides in this source, is not well explained by conventional gas-phase LTE and non-LTE chemical models, and may imply formation on grain surfaces. Based on observations carried out with the IRAM 30-m telescope and the Caltech Submillimeter Observatory (CSO). IRAM is supported by INSU/CNRS (France), MPG (Germany), and IGN (Spain). The CSO is operated by the California Institute of Technology under funding from the National Science Foundation, Grant No. AST-0540882.

  6. 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-...

  7. 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

  8. 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

  9. Synthesis and structural characterization of isolable phosphine coinage metal ?-complexes

    PubMed Central

    Shapiro, Nathan D.; Toste, F. Dean

    2008-01-01

    The chemical community has recently witnessed a dramatic increase in the application of cationic gold(I)-phosphine complexes as homogeneous catalysts for organic synthesis. The majority of gold(I)-catalyzed reactions rely on nucleophilic additions to carboncarbon multiple bonds, which have been activated by coordination to a cationic gold(I) catalyst. However, structural evidence for coordination of cationic gold(I) complexes to alkynes has been limited. Here, we report the crystal structure of a gold(I)-phosphine ?2-coordinated alkyne. Related Ag(I) and Cu(I) complexes have been synthesized for comparison. The crystallization of these complexes was enabled by tethering a labile alkyne ligand to a strongly coordinating triarylphosphine. This approach also proved applicable to crystallization of the first gold(I)-phosphine ?2-coordinated alkene.

  10. Submicromolar Phosphinic Inhibitors of E. coli Aspartate Transcarbamoylase

    PubMed Central

    Coudray, Latitia; 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; Artemev, 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, 730 h) to afford 1-hydroxy-2-(organosulfanyl)ethyl(diorganyl)phosphine oxides in 7093% yields. PMID:26664618

  12. 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

  13. 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.

  14. 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.

  15. Biaryl Phosphine Ligands in Palladium-Catalyzed Amination

    PubMed Central

    Surry, David S.

    2012-01-01

    Palladium-catalyzed amination of aryl halides has undergone rapid development in the last 12 years. This has been largely driven by implementation of new classes of ligands. Biaryl phosphines have proven to provide especially active catalysts in this context. This review discusses the applications that these catalysts have found in C-N cross-coupling in heterocycle synthesis, pharmaceuticals, materials science and natural product synthesis. PMID:18663711

  16. Zirconium-catalyzed intermolecular hydrophosphination using a chiral, air-stable primary phosphine.

    PubMed

    Bange, Christine A; Ghebreab, Michael B; Ficks, Arne; Mucha, Neil T; Higham, Lee; Waterman, Rory

    2016-02-01

    Catalytic hydrophosphination of alkenes using a chiral, air-stable primary phosphine, (R)-[2'-methoxy(1,1'-binapthalen)-2-yl]phosphine, (R)-MeO-MOPH2, proceeds under mild conditions with a zirconium catalyst, [?(5)-N,N,N,N,C-(Me3SiNCH2CH2)2NCH2CH2NSiMe2CH]Zr (1), to selectively furnish anti-Markovnikov, air-stable secondary phosphines or tertiary phosphines with slight modification of the protocol. An intermediate in the catalysis, [(N3N)Zr(R)-MeO-MOPH] (4), was structurally characterized. PMID:26530894

  17. 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

  18. Effects of phosphine on the neural regulation of gas exchange in Periplaneta americana.

    PubMed

    Woodman, James D; Haritos, Victoria S; Cooper, Paul D

    2008-04-01

    Phosphine is used for fumigating stored commodities, however an understanding of the physiological response to phosphine in insects is limited. Here we show how the central pattern generator for ventilation in the central nervous system (CNS) responds to phosphine and influences normal resting gas exchange. Using the American cockroach, Periplaneta americana, that perform discontinuous gas exchange (DGE) at rest, we simultaneously measure ventilatory nervous output from the intact CNS, VCO(2) and water loss from live specimens. Exposure to 800 ppm phosphine at 25 degrees C for 2 h (n=13) during recording did not cause any mortality or obvious sub-lethal effects. Within 60 s of introducing phosphine into the air flow, all animals showed a distinct CNS response accompanied by a burst release of CO(2). The initial ventilatory response to phosphine displaced DGE and was typically followed by low, stable and continuous CO(2) output. CNS output was highest and most orderly under normoxic conditions during DGE. Phosphine caused a series of ventilatory CNS spikes preceding almost complete cessation of CNS output. Minimal CNS output was maintained during the 2 h normoxic recovery period and DGE was not reinstated. VCO(2) was slightly reduced and water loss significantly lower during the recovery period compared with those rates prior to phosphine exposure. A phosphine narcosis effect is rejected based on animals remaining alert at all times during exposure. PMID:18158274

  19. 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

  20. Structural, spectroscopic and computational examination of the dative interaction in constrained phosphine-stibines and phosphine-stiboranes.

    PubMed

    Chalmers, Brian A; Bhl, Michael; Athukorala Arachchige, Kasun S; Slawin, Alexandra M Z; Kilian, Petr

    2015-05-11

    A series of phosphine-stibine and phosphine-stiborane peri-substituted acenaphthenes containing all permutations of pentavalent groups -SbCln Ph4-n (5-9), as well as trivalent groups -SbCl2 , -Sb(R)Cl, and -SbPh2 (2-4, R=Ph, Mes), were synthesised and fully characterised by single crystal diffraction and multinuclear NMR spectroscopy. In addition, the bonding in these species was studied by DFT computational methods. The P-Sb dative interactions in both series range from strongly bonding to non-bonding as the Lewis acidity of the Sb acceptor is decreased. In the pentavalent antimony series, a significant change in the P-Sb distance is observed between -SbClPh3 and -SbCl2 Ph2 derivatives 6 and 7, respectively, consistent with a change from a bonding to a non-bonding interaction in response to relatively small modification in Lewis acidity of the acceptor. In the Sb(III) series, two geometric forms are observed. The P-Sb bond length in the SbCl2 derivative 2 is as expected for a normal (rather than a dative) bond. Rather unexpectedly, the phosphine-stiborane complexes 5-9 represent the first examples of the ?(4) P??(6) Sb structural motif. PMID:25820876

  1. 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

  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. PHOSPHINE-MEDIATED HEINZ BODY FORMATION AND HEMOGLOBIN OXIDATION IN HUMAN ERYTHROCYTES

    EPA Science Inventory

    Exposure of hen erythrocytes in vitro to phosphine (PH 3) induces the development of Heinz body lesions. he lower limit for phosphine mediated Heinz body formation is 1.25 ppm for a four hour exposure. t exposure levels of 3.0 ppm or higher all erythrocytes are observed to contai...

  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. P-Arylation of Dialkyl Phosphites and Secondary Phosphine Oxides with Arynes.

    PubMed

    Chen, Qian; Yan, Xinxing; Du, Zhiyun; Zhang, Kun; Wen, Chunxiao

    2016-01-01

    The novel P-arylation of dialkyl phosphites and secondary phosphine oxides with arynes has been achieved. The reactions produce dialkyl arylphosphonates in 71-99% yield and tertiary phosphine oxides in 68-92% yield under mild conditions. PMID:26651021

  6. Unprecedented selective aminolysis: Aminopropyl phosphine as a building block for a new family of air stable mono-, bis-, and tris-primary phosphines

    SciTech Connect

    Prabhu, K.R.; Pillarsetty, N.; Gali, H.; Katti, K.V.

    2000-02-23

    A serious impediment to using primary and secondary phosphines as general-purpose reagents to develop new chemistry is associated with their unpleasant pyrophoric nature and extreme hydrolytic, thermal, and oxidative instabilities. In particular, primary phosphines with ``user friendly'' properties (e.g., good oxidative/thermal stability, low volatility) would be extremely important not only from the synthetic point of view but also for potential application (e.g., in dendrimers formation). As part of ongoing research on the fundamental main group and organic chemistry of functionalized phosphorus compounds, the authors report, herein, unprecedented selectivity in the reaction of 3-aminopropyl primary phosphine 3, with the methyl ester in the presence of free acid, amide, and thiol to produce air stable amide, carboxylate, and thiol functionalized primary phosphines.

  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. Phosphinate-containing heterocycles: A mini-review

    PubMed Central

    Berger, Olivier

    2014-01-01

    Summary This review provides an overview of recent efforts towards the synthesis of phosphinate heterocycles R1R2P(O)(OR). Our laboratory and others have been involved in this field and as a result new PC, PN, and PO containing heterocyclic motifs are now available through a variety of methods. While developing rapidly, this area is still in its infancy so that biological testing of the compounds has not yet been conducted and applications are rare. The growing availability of synthetic methods will undoubtedly change this situation in the near future. PMID:24778726

  9. 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.

  10. Spontaneous dehydrocoupling in peri-substituted phosphine-borane adducts.

    PubMed

    Taylor, Laurence J; Surgenor, Brian A; Wawrzyniak, Piotr; Ray, Matthew J; Cordes, David B; Slawin, Alexandra M Z; Kilian, Petr

    2016-02-01

    Bis(borane) adducts Acenap(PiPr2BH3)(PRHBH3) (Acenap = acenaphthene-5,6-diyl; 4a, R = Ph; 4b, R = ferrocenyl, Fc; 4c, R = H) were synthesised by the reaction of excess H3BSMe2 with either phosphino-phosphonium salts [Acenap(PiPr2)(PR)](+)Cl(-) (1a, R = Ph; 1b, R = Fc), or bis(phosphine) Acenap(PiPr2)(PH2) (3). Bis(borane) adducts 4a-c were found to undergo dihydrogen elimination at room temperature, this spontaneous catalyst-free phosphine-borane dehydrocoupling yields BH2 bridged species Acenap(PiPr2)(?-BH2)(PRBH3) (5a, R = Ph; 5b, R = Fc; 5c, R = H). Thermolysis of 5c results in loss of the terminal borane moiety to afford Acenap(PiPr2)(?-BH2)(PH) (14). Single crystal X-ray structures of 3, 4b and 5a-c are reported. PMID:26314761

  11. Do phosphine resistance genes influence movement and dispersal under starvation?

    PubMed

    Kaur, Ramandeep; Ebert, Paul R; Walter, Gimme H; Swain, Anthony J; Schlipalius, David I

    2013-10-01

    Phosphine resistance alleles might be expected to negatively affect energy demanding activities such as walking and flying, because of the inverse relationship between phosphine resistance and respiration. We used an activity monitoring system to quantify walking of Rhyzopertha dominica (F.) and a flight chamber to estimate their propensity for flight initiation. No significant difference in the duration of walking was observed between the strongly resistant, weakly resistant, and susceptible strains of R. dominica we tested, and females walked significantly more than males regardless of genotype. The walking activity monitor revealed no pattern of movement across the day and no particular time of peak activity despite reports of peak activity of R. dominica and Tribolium castaneum (Herbst) under field conditions during dawn and dusk. Flight initiation was significantly higher for all strains at 28 degrees C and 55% relative humidity than at 25, 30, 32, and 35 degrees C in the first 24 h of placing beetles in the flight chamber. Food deprivation and genotype had no significant effect on flight initiation. Our results suggest that known resistance alleles in R. dominica do not affect insect mobility and should therefore not inhibit the dispersal of resistant insects in the field. PMID:24224272

  12. 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

  13. Synthesis of P,N-Heterocycles from ?-Amino-H-Phosphinates: Conformationally Restricted ?-Amino Acid Analogs

    PubMed Central

    Queffelec, Clmence; Ribire, Patrice; Montchamp, Jean-Luc

    2009-01-01

    P,N-Heterocycles (3-hydroxy-1,3-azaphospholane and 3-hydroxy-1,3-azaphosphorinane-3-oxide) are synthesized in moderate yield from readily available ?-amino-H-phosphinates and aldehydes or ketones via an intramolecular Kabachnik-Fields reaction. The products are conformationally restricted phosphinic analogs of ?-amino acids. The multi-gram scale syntheses of the H2N(CH2)nPO2H2 phosphinic precursors (n = 1, 2, 3) and some derivatives are also described. PMID:18855477

  14. Green, Palladium-Catalyzed Synthesis of Benzylic H-phosphinates from Hypophosphorous Acid and Benzylic Alcohols

    PubMed Central

    Coudray, Latitia

    2013-01-01

    Benzylic alcohols cross-couple directly with concentrated H3PO2 using Pd/xantphos (1 or 2 mol-%). Depending on the substrate, DMF at 110C, or t-AmOH at reflux with a Dean-Stark trap, can be used. A broad range of benzylic alcohols reacted successfully in moderate to good yields. The preparation of other organophosphorus compounds (phosphinic and phosphonic acids) is also demonstrated. Asymmetric reaction with (R)-1-(2-naphthyl)ethanol provided the corresponding H-phosphinic acid in 77% ee. The methodology provides a green, PCl3-free, entry into benzylic-H-phosphinic acids. PMID:23349619

  15. Dynamic control of chirality in phosphine ligands for enantioselective catalysis

    PubMed Central

    Zhao, Depeng; Neubauer, Thomas M.; Feringa, Ben L.

    2015-01-01

    Chirality plays a fundamental role in biology and chemistry and the precise control of chirality in a catalytic conversion is a key to modern synthesis most prominently seen in the production of pharmaceuticals. In enantioselective metal-based catalysis, access to each product enantiomer is commonly achieved through ligand design with chiral bisphosphines being widely applied as privileged ligands. Switchable phosphine ligands, in which chirality is modulated through an external trigger signal, might offer attractive possibilities to change enantioselectivity in a catalytic process in a non-invasive manner avoiding renewed ligand synthesis. Here we demonstrate that a photoswitchable chiral bisphosphine based on a unidirectional light-driven molecular motor, can be used to invert the stereoselectivity of a palladium-catalysed asymmetric transformation. It is shown that light-induced changes in geometry and helicity of the switchable ligand enable excellent selectivity towards the racemic or individual enantiomers of the product in a Pd-catalysed desymmetrization reaction. PMID:25806856

  16. 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.

  17. 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

  18. 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

  19. 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.

  20. 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.

  1. 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...

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

    SciTech Connect

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

    2000-04-25

    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.

  3. Oxidation of phosphine by iron(III) chloride complexes supported on activated charcoal

    SciTech Connect

    Rakitskaya, T.L.; Kostyukova, I.S.; Red'ko, T.D.

    1988-06-01

    It has been discovered that iron(III) chloride complexes supported on activated charcoal oxidize phosphine under normal conditions. The process accelerates as the concentration of the chloride ions and the proton acid increases.

  4. 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

  5. Correction: Bifunctional ligands in combination with phosphines and Lewis acidic phosphoniums for the carbonylative Sonogashira reaction.

    PubMed

    Tan, Chen; Wang, Peng; Liu, Huan; Zhao, Xiao-Li; Lu, Yong; Liu, Ye

    2016-01-11

    Correction for 'Bifunctional ligands in combination with phosphines and Lewis acidic phosphoniums for the carbonylative Sonogashira reaction' by Chen Tan et al., Chem. Commun., 2015, 51, 10871-10874. PMID:26660541

  6. Oxidative hydroxylation of phosphine in aqueous alcohol solutions of p-benzoquinone

    NASA Astrophysics Data System (ADS)

    Polimbetova, G. S.; Borangazieva, A. K.; Ibraimova, Zh. U.; Ergozhin, E. E.; Mukhitdinova, B. A.

    2014-05-01

    The oxidation of phosphine in aqueous alcohol solution of benzoquinone in the presence of iodide ions is studied. Kinetic measurements, redox potentiometry, and gas chromatography are used to determine the kinetic regularities of the oxidative hydroxylation of phosphine, and a single-stage redox mechanism is proposed for this reaction. It is found that the iodine resulting from the oxidation of I- ions by quinone is the reagent responsible for the formation of phosphorus-containing products.

  7. Double Asymmetric Induction During the Addition of (RP )-Menthyl Phenyl Phosphine Oxide to Chiral Aldimines.

    PubMed

    Zhou, Zhong-Yang; Zhang, He; Yao, Lan; Wen, Jing-Hong; Nie, Shao-Zhen; Zhao, Chang-Qiu

    2016-02-01

    P,C-Stereogenic ?-amino phosphine oxides were prepared from the addition of (RP )-menthyl phenyl phosphine oxide to chiral aldimines under neat condition at 80?C in up to 91:9 drC and 99% yields. The diastereoselectivity was mainly induced by chiral phosphorus that showed matched or mismatched induction with (S)- or (R)-aldimines, respectively. Chirality 28:132-135, 2016. 2015 Wiley Periodicals, Inc. PMID:26608546

  8. Hydroxyproline-Derived Pseudoenantiomeric [2.2.1] Bicyclic Phosphines: Asymmetric Synthesis of (+)- and (?)-Pyrrolines

    PubMed Central

    2015-01-01

    We have prepared two new diastereoisomeric 2-aza-5-phosphabicyclo[2.2.1]heptanes from naturally occurring trans-4-hydroxy-l-proline in six chemical operations. These syntheses are concise and highly efficient, with straightforward purification. When we used these chiral phosphines as catalysts for reactions of ?-substituted allenoates with imines, we obtained enantiomerically enriched pyrrolines in good yields with excellent enantioselectivities. These two diastereoisomeric phosphines functioned as pseudoenantiomers, providing their chiral pyrrolines with opposite absolute configurations. PMID:25099350

  9. 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...

  10. 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...

  11. 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...

  12. 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...

  13. 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...

  14. Biomimetic peptide-based models of [FeFe]-hydrogenases: utilization of phosphine-containing peptides.

    PubMed

    Roy, Souvik; Nguyen, Thuy-Ai D; Gan, Lu; Jones, Anne K

    2015-09-01

    Two synthetic strategies for incorporating diiron analogues of [FeFe]-hydrogenases into short peptides via phosphine functional groups are described. First, utilizing the amine side chain of lysine as an anchor, phosphine carboxylic acids can be coupled via amide formation to resin-bound peptides. Second, artificial, phosphine-containing amino acids can be directly incorporated into peptides via solution phase peptide synthesis. The second approach is demonstrated using three amino acids each with a different phosphine substituent (diphenyl, diisopropyl, and diethyl phosphine). In total, five distinct monophosphine-substituted, diiron model complexes were prepared by reaction of the phosphine-peptides with diiron hexacarbonyl precursors, either (?-pdt)Fe2(CO)6 or (?-bdt)Fe2(CO)6 (pdt = propane-1,3-dithiolate, bdt = benzene-1,2-dithiolate). Formation of the complexes was confirmed by UV/Vis, FTIR and (31)P NMR spectroscopy. Electrocatalysis by these complexes is reported in the presence of acetic acid in mixed aqueous-organic solutions. Addition of water results in enhancement of the catalytic rates. PMID:26223293

  15. 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

  16. Distinction between coordination and phosphine ligand oxidation: interactions of di- and triphosphines with Pn(3+) (Pn = P, As, Sb, Bi).

    PubMed

    Chitnis, Saurabh S; Vos, Kevin A; Burford, Neil; McDonald, Robert; Ferguson, Michael J

    2015-12-24

    Reactions of polydentate phosphines with sources of Pn(3+) (Pn = P, As, Sb, Bi) yield complexes of Pn(1+) (Pn = P, As) or Pn(3+) (Pn = Sb, Bi) acceptors. The distinction between coordination of a phosphine center to Pn and oxidation of a phosphine ligand is dependent on Pn. The first structurally verified triphosphine complexes of Sb(iii) and Bi(iii) acceptors are reported. PMID:26569099

  17. Influence of structure of the metal salts of phosphinates on the performance of the fire-retardant polymers

    NASA Astrophysics Data System (ADS)

    Liu, Xueqing; Liu, Jiyan; Guo, Yuanhao; Cakmak, Miko

    2015-05-01

    Dialkylphosphinate salts (I) and amide-containing phosphinate salts(II) with varying metal cation and organic groups were used as flame retardants for epoxy resin(EP), poly(butylene terephthalate) (PBT) correspondingly. Their flame retardancy, mechanical properties, thermal stability, compatibility between phosphinate salts and polymer, and leaching of the salts from the polymer were investigated with respect to the structure of phosphinate salts.

  18. PC bond formation via PH addition of a fluoroaryl phosphinic acid to ketones

    PubMed Central

    Orthaber, Andreas; Albering, Jrg H.; Belaj, Ferdinand; Pietschnig, Rudolf

    2010-01-01

    The synthesis, structure and reactivity of the fluoroaryl phosphinic acid HF4C6P(O)HOH is reported and compared to a sterically comparable yet non-fluorinated analog with similar size. The fluoroaryl phosphinic acid undergoes reversible PH addition to the carbonyl functionality of ketones under formation of a PC bond which is retained in the resulting ?-hydroxy phosphinic acid. The latter shows an extended 2D hydrogen bonded network in the solid state. PMID:21072125

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

    PubMed

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

    2014-01-01

    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

  20. 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

  1. 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).

  2. 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.

  3. 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.

  4. 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

  5. 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

  6. 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.

  7. 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.

  8. 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

  9. Palladium-catalyzed asymmetric addition of diarylphosphines to ?,?-unsaturated sulfonic esters for the synthesis of chiral phosphine sulfonate compounds.

    PubMed

    Lu, Junzhu; Ye, Jinxing; Duan, Wei-Liang

    2013-10-01

    Highly stereoselective addition of diarylphosphines to ?,?-unsaturated sulfonic esters catalyzed through a PCP pincer-Pd complex is developed to synthesize chiral phosphine sulfonic esters with excellent enantioselectivity (up to 99.5% ee). The transformation of the chiral adduct into a useful palladium phosphine sulfonate complex is also demonstrated. PMID:24050605

  10. Targeted synthesis of electroactive porous organic frameworks containing triphenyl phosphine moieties.

    PubMed

    Pei, Cuiying; Ben, Teng; Guo, Han; Xu, Jun; Deng, Feng; Xiang, Zhonghua; Cao, Dapeng; Qiu, Shilun

    2013-10-13

    A novel electroactive porous aromatic framework (JUC-Z4-Cl) was designed and synthesized via Yamamoto-type Ullmann cross-coupling reaction with the monomer tris(4-chlorophenyl)phosphine. By simple redox chemical reactions, stable, reductive, porous polytri(p-phenyl)phosphine (JUC-Z4) and polytri(p-phenyl)phosphine oxide (JUC-Z5) could be obtained as off-white powders. The structures of JUC-Z4 and JUC-Z5 were confirmed using magic-angle spinning nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, etc. The microporous architectures exhibit high stability (471C for JUC-Z4 and 484C for JUC-Z5) and large surface area (793 and 648 m g? for JUC-Z4 and JUC-Z5, respectively). JUC-Z4 also exhibits efficient recognition ability of greenhouse gases from dry air. PMID:24000364

  11. Synthesis of a hybrid m-terphenyl/o-carborane building block: applications in phosphine ligand design.

    PubMed

    Lugo, Christopher A; Moore, Curtis E; Rheingold, Arnold L; Lavallo, Vincent

    2015-03-01

    A hybrid terphenyl/o-carborane ligand building block is synthesized by the reaction of m-terphenylalkyne with B10H14. This sterically demanding substituent can be installed into ligands, as demonstrated by the preparation of carboranylphosphine. The bulky phosphine reacts with [ClRh(CO)2]2 to produce monophosphine complex ClRhL(CO)2, which subsequently extrudes CO under vacuum to afford the dimeric species [ClRhL(CO)]2. The latter complex does not react with excess phosphine and is resistant toward cyclometalation, which is in contrast to related o-carborane phosphine complexes. Data from a single-crystal X-ray diffraction study are utilized to quantify the steric impact of the ligand via the percent buried volume approach. PMID:25668570

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

    PubMed

    Macegoniuk, Katarzyna; Dzie?ak, Anna; Mucha, Artur; Berlicki, ?ukasz

    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

  13. 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

  14. Fixed-charge phosphine ligands to explore gas-phase coinage metal-mediated decarboxylation reactions.

    PubMed

    Vikse, Krista; Khairallah, George N; McIndoe, J Scott; O'Hair, Richard A J

    2013-05-14

    A combination of multistage mass spectrometry experiments and density functional theory (DFT) calculations were used to examine the decarboxylation reactions of a series of metal carboxylate complexes bearing a fixed-charge phosphine ligand, [(O3SC6H4)(C6H5)2PM(I)O2CR](-) (M = Cu, Ag, Au; R = Me, Et, benzyl, Ph). Collision-induced dissociation (CID) of these complexes using an LTQ linear ion mass spectrometer results in three main classes of reactions being observed: (1) decarboxylation; (2) loss of the phosphine ligand; (3) loss of carboxylic acid. The gas-phase unimolecular chemistry of the resultant decarboxylated organometallic ions, [(O3SC6H4)(C6H5)2PM(I)R](-), were also explored using CID experiments, and fragment primarily via loss of the phosphine ligand. Energy-resolved CID experiments on [(O3SC6H4)(C6H5)2PM(I)O2CR](-) (M = Cu, Ag, Au; R = Me, Et, benzyl, Ph) using a Q-TOF mass spectrometer were performed to gain a more detailed understanding of the factors influencing coinage metal-catalyzed decarboxylation and DFT calculations on the major fragmentation pathways aided in interpretation of the experimental results. Key findings are that: (1) the energy required for loss of the phosphine ligand follows the order Ag < Cu < Au; (2) the ease of decarboxylation of the coordinated RCO2 groups follows the order of R: Ph < PhCH2 < Me < Et; (3) in general, copper is best at facilitating decarboxylation, followed by gold then silver. The one exception to this trend is when R = Ph and M = Au which has the highest overall propensity for decarboxylation. The influence of the phosphine ligand on decarboxylation is also considered in comparison with previous studies on metal carboxylates that do not contain a phosphine ligand. PMID:23467311

  15. Mitochondrial uncouplers act synergistically with the fumigant phosphine to disrupt mitochondrial membrane potential and cause cell death.

    PubMed

    Valmas, Nicholas; Zuryn, Steven; Ebert, Paul R

    2008-10-30

    Phosphine is the most widely used fumigant for the protection of stored commodities against insect pests, especially food products such as grain. However, pest insects are developing resistance to phosphine and thereby threatening its future use. As phosphine inhibits cytochrome c oxidase (complex IV) of the mitochondrial respiratory chain and reduces the strength of the mitochondrial membrane potential (DeltaPsi(m)), we reasoned that mitochondrial uncouplers should act synergistically with phosphine. The mitochondrial uncouplers FCCP and PCP caused complete mortality in populations of both wild-type and phosphine-resistant lines of Caenorhabditis elegans simultaneously exposed to uncoupler and phosphine at concentrations that were individually nonlethal. Strong synergism was also observed with a third uncoupler DNP. We have also tested an alternative complex IV inhibitor, azide, with FCCP and found that this also caused a synergistic enhancement of toxicity in C. elegans. To investigate potential causes of the synergism, we measured DeltaPsi(m), ATP content, and oxidative damage (lipid hydroperoxides) in nematodes subjected to phosphine-FCCP treatment and found that neither an observed 50% depletion in ATP nor oxidative stress accounted for the synergistic effect. Instead, a synergistic reduction in DeltaPsi(m) was observed upon phosphine-FCCP co-treatment suggesting that this is directly responsible for the subsequent mortality. These results support the hypothesis that phosphine-induced mortality results from the in vivo disruption of normal mitochondrial activity. Furthermore, we have identified a novel pathway that can be targeted to overcome genetic resistance to phosphine. PMID:18755236

  16. Spectroscopic investigation of the phosphine and nitrous oxide reaction

    SciTech Connect

    Harris, D.G.

    1980-01-01

    The molecular structure of PO possesses several fetures which make it appear to be a viable laser candidate. The lowest excited electronic state is metastable, allowing a population to be built up in this reservoir. The metastable state may combine with a ground state PO molecular to form the excimer (PO)/sub 2/*. The excimer may radiatively decay emitting throughout the visible. The reactions of mixtures of phosphine and nitrous oxide were initiated by a fast electrical discharge. Film plates were taken of the emission spectra from 2300 to 9000 A. The high resolution spectra show a continuum emission beginning at 3250 A and extending throughout the visible spectrum. The continuum has molecular emission bands superimposed on it. Temporal emission studies indicate that the chemiluminescent intensity increases as the square of the reagent pressure. A standard lamp was used to correct the high resolution spectra for film response. It also allowed an estimate to be made of the photon yield of the reaction. The photon yield was found to increase linearly with pressure up to the highest pressure investigated, 666 torr, where it has the value 2 x 10/sup -4/. Flashlamp absorption and intracavity dye laser spectroscopy measurements could find no absorption which could be associated with an emitter of the continuum. Cavity tests carried out on the reaction showed no lasing action. Attempts to stimulate the chemiluminescent emission with a high power short pulse ruby laser were unsuccessful. The technique of intracavity dye laser spectroscopy which is sensitive to both loss or gain indicates that the media is transparent to 4 x 10/sup -5//cm in the region investigated, 5300 to 6500 A.

  17. Analogues of acyclic nucleosides derived from tris-(hydroxymethyl)phosphine oxide or bis-(hydroxymethyl)phosphinic acid coupled to DNA nucleobases.

    PubMed

    Nawrot, Barbara; Michalak, Olga; De Clercq, Erik; Stec, Wojciech J

    2004-11-01

    A series of novel acyclic nucleoside analogues containing bis-(hydroxymethyl)phosphinic acid (BHPA) or tris(hydroxymethyl)phosphine oxide (THPO) coupled with DNA nucleobases or with 5-fluorouracil were prepared and their antiviral activity was studied against cytomegalovirus (CMV), varicella-zoster virus (VZV), parainfluenza-virus type 3, reovirus-type 1, sindbis, coxsackie B4, punta toro, vesicular stomatitis and respiratory syncytial virus, herpes simplex virus-type 1 (KOS) and type 2 (G), vaccinia virus and herpes simplex virus-1 (TK- KOS ACVr). No specific antiviral effects were noted for any of test compounds against viruses evaluated, except thymine, cytosine and adenine derivatives of BHPA exerting borderline activity against respiratory syncytial virus at the 80 mg/ml concentration. PMID:15646645

  18. Multicomponent reactions of phosphines, enynedioates and benzylidene malononitriles generated highly substituted cyclopentenes through an unexpected phosphine ?-addition-?-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 ?(?')-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

  19. 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

  20. 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.

  1. 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 2C was studied to control western flower t...

  2. 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.

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

    PubMed

    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

  4. Synthesis of (phosphonomethyl)phosphinate pyrophosphate analogues via the phospha-Claisen condensation.

    PubMed

    Gelat, Fabien; Lacomme, Claire; Berger, Olivier; Gavara, Laurent; Montchamp, J-L

    2015-01-21

    Pyrophosphate analogues are of great importance especially for the design of biologically active molecules. The phospha-Claisen condensation allows for the rapid synthesis of (phosphonomethyl)phosphinate pyrophosphate analogues and building blocks that can be employed in numerous applications. PMID:25407406

  5. 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…

  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. 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

  8. 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...

  9. 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...

  10. 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

  11. 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

  12. Synthesis of anionic methylpalladium complexes with phosphine-sulfonate ligands and their activities for olefin polymerization.

    PubMed

    Kochi, Takuya; Yoshimura, Kenji; Nozaki, Kyoko

    2006-01-01

    Reaction of diarylphosphinobenzene-2-sulfonic acids with tertially amines, followed by addition of [PdMeCl(cod)], provided anionic methylpalladium(II) complexes with bidentate phosphine-sulfonate ligands, which show high activity for copolymerization of ethylene with methyl acrylate. PMID:16357956

  13. 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 20C (68F) or higher, and ...

  14. Lithium cation enhances anion binding in a tripodal phosphine oxide-based ditopic receptor

    PubMed Central

    Gavette, Jesse V.; Lara, Juven; Berryman, Orion B.; Zakharov, Lev N.; Haley, Michael M.; Johnson, Darren W.

    2012-01-01

    A tripodal ditopic receptor presents H-bond donors and a phosphine oxide to potential guests. In the idealized binding conformation, an endohedral P?O functionality provides enhanced halide binding in the presence of lithium with the greatest ??G observed for bromide, while minimal changes in Ka are observed in the presence of sodium. PMID:21655566

  15. 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.

  16. 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.

  17. 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

  18. 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

  19. Continuous real-time monitoring of phosphine concentrations in air using electrochemical detectors interfaced by radio telemetry.

    PubMed

    Thorn, Tommy G; Chodyniecki, Edward M; Ingold, Kenneth W; Long, Gerald A; Miller, Charles D; Robinson, Edward A; Cowan, F Scott; Thomas, Robert L

    2002-05-01

    This work involves the novel use of a radio telemetry-based system that continuously monitors phosphine using two different types of electrochemical detectors (ECD/RT). The ECD/RT units were used to monitor phosphine inside and at varying distances from large tobacco storage warehouses. A master controller unit transferred the data to a personal computer that received and displayed the data. Supervisory control and data acquisition software assimilated the data from each ECD/RT unit, displayed and updated it as new transmissions were received, and stored the data in secure databases. Phosphine concentrations outside five warehouses simultaneously under fumigation and at the facility boundaries were <0.3 parts per million (ppm). Phosphine levels ranged from 0 to 580 ppm inside sealed warehouses. A comparison was made between the data collected at an ECD/RT unit approximately 4 m downwind of a sealed warehouse and a colorimetric tube at the same location. The final phosphine concentration from the colorimetric method was 0.05 ppm and the average over the 20-minute collection period for the ECD/RT was 0.13 ppm. This system allows for continuous, remote monitoring around warehouses under fumigation and superior time resolution allowing timely response to fugitive emissions of phosphine. PMID:12026991

  20. 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

  1. Oxygenated Phosphine Fumigation for Control of Light Brown Apple Moth (Lepidoptera: Tortricidae) Eggs on Cut-Flowers.

    PubMed

    Liu, Samuel S; Liu, Yong-Biao; Simmons, Gregory S

    2015-08-01

    Light brown apple moth, Epiphyas postvittana (Walker), eggs were subjected to oxygenated phosphine fumigation treatments under 70% oxygen 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 2,500?ppm phosphine for 72?h at 5C. Egg mortality and postharvest quality of cut flowers were determined after fumigation. Egg mortalities of 99.7-100% were achieved among the cut flower species. The treatment was safe to all cut flowers except gerbera daisy. A 96-h fumigation treatment with 2,200?ppm phosphine of eggs on chrysanthemums cut flowers also did not achieve complete control of light brown apple moth eggs. A simulation of fumigation in hermetically sealed fumigation chambers with gerbera daisy showed significant accumulations of carbon dioxide and ethylene by the end of 72-h sealing. However, oxygenated phosphine fumigations with carbon dioxide and ethylene absorbents did not reduce the injury to gerbera daisy, indicating that it is likely that phosphine may directly cause the injury to gerbera daisy cut flowers. The study demonstrated that oxygenated phosphine fumigation is effective against light brown apple moth eggs. However, it may not be able to achieve the probit9 quarantine level of control and the treatment was safe to most of the cut flower species. PMID:26470303

  2. Sulfonated poly(arylene ether phosphine oxide ketone) block copolymers as oxidatively stable proton conductive membranes.

    PubMed

    Miyake, Junpei; Watanabe, Masahiro; Miyatake, Kenji

    2013-07-10

    The introduction of triphenylphosphine oxide moiety into the hydrophilic segments of aromatic multiblock copolymers provided outstanding oxidative stability and high proton conductivity. Our designed multiblock copolymers are composed of highly sulfonated phenylene ether phosphine oxide ketone units as hydrophilic blocks and phenylene ether biphenylene sulfone units as hydrophobic blocks. High molecular weight block copolymers (Mw = 204-309 kDa and Mn = 72-94 kDa) with different copolymer compositions (number of repeat unit in the hydrophobic blocks, X = 30, and that of hydrophilic blocks, Y = 4, 6, or 8) were synthesized, resulting in self-standing, transparent, and bendable membranes by solution-casting. The block copolymer membranes exhibited well-developed hydrophilic/hydrophobic phase separation, high proton conductivity, and excellent oxidative stability due to the highly sulfonated hydrophilic blocks, which contained phenylene rings with sulfonic acid groups and electron-withdrawing phosphine oxide or ketone groups. PMID:23803149

  3. 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.

  4. Syntheses and properties of phosphine-substituted ruthenium(II) polypyridine complexes with nitrogen oxides.

    PubMed

    Nakamura, Go; Kondo, Mio; Crisalli, Meredith; Lee, Sze Koon; Shibata, Akane; Ford, Peter C; Masaoka, Shigeyuki

    2015-10-21

    Four novel phosphine-substituted ruthenium(ii) polypyridine complexes with nitrogen oxides-trans(P,NO2)-[Ru(trpy)(Pqn)(NO2)]PF6 (trans-NO2), cis(P,NO2)-[Ru(trpy)(Pqn)(NO2)]PF6 (cis-NO2), [Ru(trpy)(dppbz)(NO2)]PF6 (PP-NO2), and cis(P,NO)-[Ru(trpy)(Pqn)(NO)](PF6)3 (cis-NO)-were synthesised (trpy = 2,2':6',2''-terpyridine, Pqn = 8-(diphenylphosphanyl)quinoline, and dppbz = 1,2-bis(diphenylphosphanyl)benzene). The influence of the number and position of the phosphine group(s) on the electronic structure of these complexes was investigated using single-crystal X-ray structural analysis, UV-vis absorption spectroscopy, and electrochemical measurements. The substitution lability of the nitrogen oxide ligand of each complex is discussed in comparison with that of the corresponding acetonitrile complexes. PMID:26373342

  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. 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.

  7. 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.

  8. 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.

  9. Dendritic (phosphine)gold(I) thiolate complexes: assessment of the molecular size through PGSE NMR studies.

    PubMed

    Fernndez, Eduardo J; Laguna, Antonio; Monge, Miguel; Montiel, Manuel; Olmos, M Elena; Prez, Javier; Snchez-Forcada, Eva

    2009-01-21

    The reactions of the tetraphosphine ligand DAB-G0-(PPh2)4 (DAB = 1,4-diaminobutane; G0 = Generation 0) or the octaphosphine ligand DAB-G1-(PPh2)8 (G1 = Generation 1) with the gold precursor [AuCl(tht)] (tht =tetrahydrothiophene) and the corresponding 4-substituted benzenethiolate lead to the (phosphine)gold(I) thiolate complexes [Au4(S-C6H4-X)4[(DAB-G0-(PPh2)4

  10. P-chiral phosphine-sulfonate/palladium-catalyzed asymmetric copolymerization of vinyl acetate with carbon monoxide.

    PubMed

    Nakamura, Akifumi; Kageyama, Takeharu; Goto, Hiroki; Carrow, Brad P; Ito, Shingo; Nozaki, Kyoko

    2012-08-01

    Utilization of palladium catalysts bearing a P-chiral phosphine-sulfonate ligand enabled asymmetric copolymerization of vinyl acetate with carbon monoxide. The obtained ?-polyketones have head-to-tail and isotactic polymer structures. The origin of the regio- and stereoregularities was elucidated by stoichiometric reactions of acylpalladium complexes with vinyl acetate. The present report for the first time demonstrates successful asymmetric coordination-insertion (co)polymerization of vinyl acetate. PMID:22823453

  11. Ethylene/allyl monomer cooligomerization by nickel/phosphine-sulfonate catalysts.

    PubMed

    Ito, Shingo; Ota, Yusuke; Nozaki, Kyoko

    2012-12-01

    Nickel(II) complexes bearing a phosphine-sulfonate ligand, [(R(2)PC(6)H(4)SO(3))NiMe(2,6-lutidine)] (R = cyclohexyl, 2-MeOC(6)H(4), and 2-[2',6'-(MeO)(2)C(6)H(3)]C(6)H(4), were synthesized and applied as catalysts for the cooligomerizations of ethylene and allyl monomers. PMID:23059906

  12. 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.

  13. 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

  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. 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

  17. 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

  18. 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

  19. 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.

  20. 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

  1. Thermochromic luminescence of copper iodide clusters: the case of phosphine ligands.

    PubMed

    Perruchas, Sandrine; Tard, Cdric; Le Goff, Xavier F; Fargues, Alexandre; Garcia, Alain; Kahlal, Samia; Saillard, Jean-Yves; Gacoin, Thierry; Boilot, Jean-Pierre

    2011-11-01

    Three copper(I) iodide clusters coordinated by different phosphine ligands formulated [Cu(4)I(4)(PPh(3))(4)] (1), [Cu(4)I(4)(Pcpent(3))(4)] (2), and [Cu(4)I(4)(PPh(2)Pr)(4)] (3) (PPh(3) = triphenylphosphine, Pcpent(3) = tricyclopentylphosphine, and PPh(2)Pr = diphenylpropylphosphine) have been synthesized and characterized by (1)H and (31)P NMR, elemental analysis and single crystal X-ray diffraction analysis. They crystallize in different space groups, namely, monoclinic P21/c, cubic Pa ?3, and tetragonal I ?42m for 1, 2, and 3, respectively. The photoluminescence properties of clusters 1 and 3 show reversible luminescence thermochromism with two highly intense emission bands whose intensities are temperature dependent. In accordance to Density Functional Theory (DFT) calculations, these two emission bands have been attributed to two different transitions, a cluster centered (CC) one and a mixed XMCT/XLCT one. Cluster 2 does not exhibit luminescence variation in temperature because of the lack of the latter transition. The absorption spectra of the three clusters have been also rationalized by time dependent DFT (TDDFT) calculations. A simplified model is suggested to represent the luminescence thermochromism attributed to the two different excited states in thermal equilibrium. In contrast with the pyridine derivatives, similar excitation profiles and low activation energy for these phosphine-based clusters reflect high coupling of the two emissive states. The effect of the Cu-Cu interactions on the emission properties of these clusters is also discussed. Especially, cluster 3 with long Cu-Cu contacts exhibits a controlled thermochromic luminescence which is to our knowledge, unknown for this family of copper iodide clusters. These phosphine-based clusters appear particularly interesting for the synthesis of original emissive materials. PMID:21957984

  2. 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

  3. 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.

  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. Self-assembled supramolecular clusters based on phosphines and coinage metals: tetrahedra, helicates, and mesocates.

    PubMed

    Lim, Sang Ho; Cohen, Seth M

    2013-07-15

    An array of coordination-driven supramolecular metal-ligand clusters has been synthesized using polytopic phosphine ligands and coinage metals (Cu(+), Ag(+), Au(+)). Rigid 3-fold or 2-fold symmetric phosphine ligands have been prepared: 1,3,5-tris((4-(diphenylphosphino)ethynyl)phenyl)benzene) (tppepb, L(1)), 1,4-bis((diphenylphosphino)ethynyl)benzene (1,4-dppeb, L(2)), 1,3-bis((diphenylphosphino)ethynyl)benzene (1,3-dppeb, L(3)), 2,6-bis((diphenylphosphino)ethynyl)pyridine (2,6-dppep, L(4)), and 1,5-bis((diphenylphosphino)ethynyl)naphthalene (1,5-dppen, L(5)). Self-assembly of these ligands with coinage metals produces four different types of metal-ligand clusters, or in some cases coordination polymers, depending on number and relative geometry of the phosphine donor atoms. Supramolecular tetrahedral clusters of the formula M4(L(1))4I4 (M = Cu(+), Ag(+), Au(+)) were obtained with the tppepb ligand, encapsulating solvent molecules (either CH2Cl2 or DMF) as guests within the central cavity of the clusters. The ligands 1,3-dppeb (L(3)) and 2,6-dppep (L(4)) give achiral, triple-stranded, dinuclear mesocates with the formula M2(L)3I2 (M = Cu(+) or Au(+)). In contrast, the ligand 1,4-dppeb (L(2)) generates a triple-stranded, dinuclear helicate with Cu(+), but a coordination polymer with Au(+) (both with the empirical formula M2(L(2))3I2). Finally, coordination polymers were obtained from 1,5-dppen (L(5)) with Cu(+). The clusters have been fully characterized by single crystal X-ray crystallography, high-resolution mass spectrometry, (1)H NMR, and (31)P NMR. PMID:23799780

  7. A Search for Phosphine in Circumstellar Envelopes: PH3 in IRC +10216 and CRL 2688?

    NASA Astrophysics Data System (ADS)

    Tenenbaum, E. D.; Ziurys, L. M.

    2008-06-01

    We present the results of a search for the JK=10-->00 transition of PH3 (phosphine) at 267 GHz toward several circumstellar envelopes using the Arizona Radio Observatory 10 m Submillimeter Telescope (SMT). In the carbon-rich shells of IRC +10216 and CRL 2688, we have detected emission lines exactly at the PH3 frequency. Toward the oxygen-rich supergiant VY Canis Majoris, only an upper limit was obtained, while in the evolved carbon-rich proto-planetary nebula CRL 618, the transition is contaminated by vibrationally excited HC3N (?7 = 4). The line shape in IRC +10216 appears to consist of two distinct components: a flat-topped profile with a width of ~28 km s-1, as is typical for this source, and a narrower feature approximately 4 km s-1 wide. The narrow component likely arises from the inner envelope (r<8R*) where the gas has not reached the terminal expansion velocity, or it is nonthermal emission. Based on the broader component, the abundance of PH3 with respect to H2 is estimated to be 5 10-8 in a region with a radius of r<150R*. If the narrower component is thermal, it implies a phosphine abundance of ~5 10-7 close to the stellar photosphere (r<8R*). In CRL 2688, the PH 3 abundance is less constrained, with plausible values ranging from 3 10 -8 to 4 10-7, assuming a spherical distribution. Phosphine appears to be present in large concentrations in the inner envelope of C-rich AGB stars, and thus may function as a parent molecule for other phosphorus species.

  8. Ruthenium Complexes Stabilized by Bidentate Enamido-Phosphine Ligands: Aspects of Cooperative H2 Activation.

    PubMed

    Wambach, Truman C; Fryzuk, Michael D

    2015-06-15

    Four bidentate, hybrid ligands ((R)(NP)(R')H) featuring imine-nitrogen and alkyl-phosphine donors linked by a cyclopentyl ring were synthesized. The ortho position of the aryl group attached to nitrogen is varied such that R is Me or Pr(i); additionally, the groups decorating phosphorus (R') are varied between Bu(t) or Pr(i). The addition of each ligand to RuHCl(PPr(i)3)2(CO) in the presence of KOBu(t) generates four enamido-phosphine complexes RuH{(R)(NP)(R')}(PPr(i)3)(CO) that were characterized by NMR spectroscopy, elemental analyses, and, in the case of R = Pr(i) and R' = Bu(t) or Pr(i), X-ray crystallography. Depending on R', the reaction of RuH{(R)(NP)(R')}(PPr(i)3)(CO) with H2 generates varying amounts of the imine-phosphine complex RuH2{(R)(NP)(R')H}(PPr(i)3)(CO). Insights into the mechanism of H2 activation by these enamido derivatives were explored using RuH{(Pr)(NP)(Pri)}(PPr(i)3)(CO), for which an intermediate was identified as the dihydrogen-dihydride complex, RuH2(H2){(Pri)(NP)(Pri)H}(PPr(i)3)(CO), on the basis of the T1,min value of 22 ms for the (1)H NMR resonance at ? -7.2 at 238 K (measured at 400 MHz). The N donor of the enamine tautomeric form of the ligand is protonated by H2 or D2 and dissociates from Ru. Tautomerization of the enamine to the imine form of the dissociated arm is involved in formation of the final product. PMID:26044815

  9. Improved fumigation process for stored foodstuffs by using phosphine in sealed chambers.

    PubMed

    Formato, Andrea; Naviglio, Daniele; Pucillo, Gian Pio; Nota, Giorgio

    2012-01-11

    In this paper we present an innovative device designed and constructed to improve the fumigation process for stored foodstuffs with the use of phosphine gas in sealed chambers. The device allowed a considerable reduction in phosphine production time (from about 5 to 7 days for traditional systems to 2 days for the equipment considered), maintaining the system below the inflammability threshold, and at the same time achieving the total exhaustion of aluminum (or magnesium) phosphide so as to avoid toxic residues at the end of the process. With the standard device currently available on the market, after the normal 5-7 day fumigating period, the powder residue contains as much as 1-2% (w/w) of phosphide. Thus the residues, according to current legislation, have to be considered toxic and harmful. To overcome this disadvantage, appropriate modifications were made to the cylindrical tray used for the fumigation process: a nebulizer was installed, which has the function of increasing the moisture of the air spreading around the phosphide pellets and allowing a more rapid reaction with phosphide. Moreover, the cylindrical tray was also heated by means of an electrical resistance, and temperature was checked by a thermostat, so as to always obtain the same efficiency, independently of outside temperature, for both hot and cold periods, since reaction speed depends on the system temperature considered. In addition, a control device for air saturation allows condensation processes to be avoided. Using the modified cylindrical tray we performed tests to determine the best values of humidity and temperature for the process concerned, avoiding phosphine concentrations that might result in a fire hazard, and the remixing of phosphide pellets inside the cylindrical tray. Our experimental data allowed us to obtain a mathematical model used to gain an insight into the process in question. PMID:22133005

  10. Phosphine-Catalyzed Formation of CarbonSulfur Bonds: Catalytic Asymmetric Synthesis of ?-Thioesters

    PubMed Central

    Sun, Jianwei; Fu, Gregory C.

    2010-01-01

    A method for the catalytic asymmetric ? sulfenylation of carbonyl compounds has been developed. In the presence of an appropriate catalyst, thiols not only add to the ? position of allenoates, overcoming their propensity to add to the ? position in the absence of a catalyst, but do so with very good enantioselectivity. Sulfur nucleophiles are now added to the three families of nucleophiles (carbon, nitrogen, and oxygen) that had earlier been shown to participate in catalyzed ? additions. The phosphine catalyst of choice, TangPhos, had previously only been employed as a chiral ligand for transition metals, not as an efficient enantioselective nucleophilic catalyst. PMID:20222657

  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. (Methanol-?O)(perchlorato-?O)bis(triphenylphosphine-?P)silver(I)

    PubMed Central

    Cui, Li-Na; Jin, Qiong-Hua; Hu, Ke-Yi; Zhang, Cun-Lin

    2010-01-01

    In the title complex, [Ag(ClO4)(CH3OH)(C18H15P)2], the angles around the central Ag+ ion indicate that it is in a distorted tetrahedral coordination. The coordination sphere of silver is formed by two P atoms of two triphenylphosphine ligands, one O atom of a perchlorate anion and one O atom of a methanol molecule. The crystal structure is stablized by a bifurcated intermolecular OH?O hydrogen bond, involving the OH donor from methanol and two acceptor O atoms from the perchlorate anion, so forming a zigzag chain propagating in [010]. PMID:21588194

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

    DOEpatents

    Crabtree, Robert H. (Bethany, CT); Brown, Stephen H. (East Haven, CT)

    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.

  14. 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.

  15. Facile, Catalytic Dehydrocoupling of Phosphines Using ?-Diketiminate Iron(II) Complexes.

    PubMed

    King, Andrew K; Buchard, Antoine; Mahon, Mary F; Webster, Ruth L

    2015-11-01

    Catalytic dehydrocoupling of primary and secondary phosphines has been achieved for the first time using an iron pre-catalyst. The reaction proceeds under mild reaction conditions and is successful with a range of diarylphosphines. A proton acceptor is not needed for the transformation to take place, but addition of 1-hexene does allow for turnover at 50?C. The catalytic system developed also facilitates the dehydrocoupling of phenylphosphane and dicyclohexylphosphane. A change in solvent switches off dehydrocoupling to allow hydrophosphination of alkenes. PMID:26406999

  16. Loss of phosphine from unsealed bins of wheat at six combinations of grain temperature and grain moisture content.

    PubMed

    Reed; Pan

    2000-07-01

    Hard red winter wheat (1.4 t) at 11.1 or 13.5% moisture content (wet basis) and 20, 25, or 30 degrees C was fumigated with tablets of an aluminum phosphide formulation in unsealed, cylindrical grain bins of corrugated metal. The fumigant leakage rate was manipulated to approximate that commonly encountered in farm and commercial-scale bins of this type. Phosphine concentration profiles were recorded and phosphine loss and sorption were characterized to determine which conditions provided the greatest probability of successful fumigation in these bins. Phosphine leakage and sorption were both positively related to grain temperature and moisture content. The fumigant concentration profiles were compared with previously-published data relating temperature to the developmental rate and fumigant susceptibility of lesser grain borer eggs, which are phosphine-resistant but become less resistant as they age. The mean phosphine concentration observed at the time corresponding to one-half of the calculated egg development time was compared to the lethal concentration (LC(99)) for a 2-day exposure at each temperature-moisture combination. In the low-moisture grain at 20 degrees C, the observed fumigant concentration was below the lethal concentration, due to the long development time under these conditions. At 25 and 30 degrees C in the low-moisture wheat, the likelihood of complete kill appeared more favorable because the fumigant concentration remained above the published LC(99) for more than half of the egg development time. In the wheat with 13.5% moisture content, rapid fumigant sorption and loss resulted in phosphine concentrations below the LC(99) at one-half of the development time at 20 or 25 degrees C. At 30 degrees C, due to the very rapid development rate, the observed phosphine concentration exceeded the LC(99) half-way through the egg development period despite the rapid rate of fumigant sorption and loss. Repeated fumigation of the same grain reduced the rate at which phosphine sorbed into the grain. PMID:10758265

  17. 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

  18. 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.

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

    NASA Astrophysics Data System (ADS)

    Grtekin Seden, Merve; Ba?trk, Emre; Inan, Tlay Y.; Kayaman Apohan, Nilhan; Gngr, 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.

  20. Synthesis of tetrakis (hydroxymethyl) phosphonium chloride by high-concentration phosphine in industrial off-gas.

    PubMed

    Huang, Xiaofeng; Wei, Yanfu; Zhou, Tao; Qin, Yangsong; Gao, Kunyang; Ding, Xinyue

    2013-01-01

    With increasing consumption of phosphate rock and acceleration of global phosphate production, the shortage of phosphate resources is increasing with the development and utilization of phosphate. China's Ministry of Land and Resources has classified phosphate as a mineral that cannot meet China's growing demand for phosphate rock in 2010. The phosphorus chemical industry is one of the important economic pillars for Yunnan province. Yellow phosphorus production in enterprises has led to a significant increase in the amount of phosphorus sludge. This paper focuses on phosphine generation in the process of phosphoric sludge utilization, where the flame retardant tetrakis (hydroxymethyl) phosphonium chloride (THPC) is synthesized by high concentrations of phosphine. The optimum conditions are determined at a space velocity of 150 h(-1), a reaction temperature of 60 C, 0.75 g of catalyst, and a ratio of raw materials of 4:1. Because of the catalytic oxidation of copper chloride (CuCl2), the synthesis of THPC was accelerated significantly. In conclusion, THPC can be efficiently synthesized under optimal conditions and with CuCl2 as a catalyst. PMID:23863426

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

    PubMed Central

    Kele?, Tu?ba; Serinda?, 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

  2. 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.

  3. /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.

  4. Phosphine resistance in India is characterised by a dihydrolipoamide dehydrogenase variant that is otherwise unobserved in eukaryotes.

    PubMed

    Kaur, R; Subbarayalu, M; Jagadeesan, R; Daglish, G J; Nayak, M K; Naik, H R; Ramasamy, S; Subramanian, C; Ebert, P R; Schlipalius, D I

    2015-09-01

    Phosphine (PH3) fumigation is the primary method worldwide for controlling insect pests of stored commodities. Over-reliance on phosphine, however, has led to the emergence of strong resistance. Detailed genetic studies previously identified two loci, rph1 and rph2, that interact synergistically to create a strong resistance phenotype. We compared the genetics of phosphine resistance in strains of Rhyzopertha dominica and Tribolium castaneum from India and Australia, countries having similar pest species but widely differing in pest management practices. Sequencing analysis of the rph2 locus, dihydrolipoamide dehydrogenase (dld), identified two structurally equivalent variants, Proline49>Serine (P49S) in one R. dominica strain and P45S in three strains of T. castaneum from India. These variants of the DLD protein likely affect FAD cofactor interaction with the enzyme. A survey of insects from storage facilities across southern India revealed that the P45/49S variant is distributed throughout the region at very high frequencies, in up to 94% of R. dominica and 97% of T. castaneum in the state of Tamil Nadu. The abundance of the P45/49S variant in insect populations contrasted sharply with the evolutionary record in which the variant was absent from eukaryotic DLD sequences. This suggests that the variant is unlikely to provide a strong selective advantage in the absence of phosphine fumigation. PMID:25853517

  5. 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 2C was studied as an alternative fumigant to meth...

  6. 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, Vronique; 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

  7. Advances in postharvest pest control on perishable commodities using ultralow oxygen treatment and low temperature phosphine funigation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Recent research in postharvest pest control on fresh fruits and vegetables for export to markets have resulted in promising ultralow oxygen (ULO) treatments and low temperature phosphine fumigation treatments for a variety of pests on different commodities. Lettuce aphid (Nasonovia ribisnigri), wes...

  8. 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

  9. 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

  10. Phosphine-Catalyzed ?,?-Umpolung Domino Reaction of Allenic Esters: Facile Synthesis of Tetrahydrobenzofuranones Bearing a Chiral Tetrasubstituted Stereogenic Carbon Center.

    PubMed

    Takizawa, Shinobu; Kishi, Kenta; Yoshida, Yasushi; Mader, Steffen; Arteaga, Fernando Arteaga; Lee, Shoukou; Hoshino, Manabu; Rueping, Magnus; Fujita, Makoto; Sasai, Hiroaki

    2015-12-14

    An enantio-, diastereo-, regio-, and chemoselective phosphine-catalyzed ?,?-umpolung domino reaction of allenic esters with dienones has been developed for the first time. The designed sequence, involving oxy-Michael and Rauhut-Currier reactions, produced highly functionalized tetrahydrobenzofuranones, bearing a chiral tetrasubstituted stereogenic center, in up to 96?% ee. PMID:26537173

  11. 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

  12. 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 ...

  13. Treatment of California stone fruit with methyl bromide or phosphine to eliminate peach twig borer, Anarsia lineatella

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The goal of this project is to develop postharvest chamber fumigations that ensure complete mortality of peach twig borer (PTB) in California stone fruit exports; results from preliminary toxicological and phytotoxicological research are presented. Fumigations with 1500 ppm phosphine over a 24 h ex...

  14. 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 PY 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 NiP 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 510 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.

  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. 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.

    1985-01-01

    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 constraints 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.

  18. 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.

  19. 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.

  20. 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

  1. High solubilities of small hydrocarbons in trihexyl tetradecylphosphonium bis(2,4,4-trimethylpentyl) phosphinate.

    PubMed

    Liu, Xiangyang; Afzal, Waheed; Yu, Guangren; He, Maogang; Prausnitz, John M

    2013-09-12

    Experimental solubilities are reported for methane, ethane, ethylene, propane, and propylene in trihexyl tetradecylphosphonium bis(2,4,4-trimethylpentyl) phosphinate [P(14)666][TMPP] from 313 to 353 K up to 6.7 MPa. A literature review on solubilities of small hydrocarbons in ionic liquids shows that solubilities in [P(14)666][TMPP] are appreciably larger than those in other ionic liquids. Contrary to solubilities in ionic liquids studied earlier, solubilities of paraffins (ethane and propane) in [P(14)666][TMPP] are larger than those of the corresponding olefins (ethylene and propylene). Because, at fixed temperature, the vapor pressure of an olefin is larger than that of the corresponding paraffin, the relative volatility of the olefin exceeds that of the corresponding paraffin, contrary to the relative volatility observed in conventional extractive distillation with polar solvents where the volatility of the paraffin exceeds that of the corresponding olefin. PMID:23947453

  2. 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-2a?(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

  3. 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.

  4. Free atmospheric phosphine concentrations and fluxes in different wetland ecosystems, China.

    PubMed

    Han, Chao; Geng, Jinju; Hong, Yuning; Zhang, Rui; Gu, Xueyuan; Wang, Xiaorong; Gao, Shixiang; Glindemann, Dietmar

    2011-02-01

    Atmospheric phosphine (PH(3)) fluxes from typical types of wetlands and PH(3) concentrations in adjacent atmospheric air were measured. The seasonal distribution of PH(3) in marsh and paddy fields were observed. Positive PH(3) fluxes are significantly related to high air temperature (summer season) and increased vegetation. It is concluded that vegetation speeds up the liberation of PH(3) from soils, while water coverage might function as a diffusion barrier from soils or sediments to the atmosphere. The concentrations of atmospheric PH(3) (ng m(-3)) above different wetlands decrease in the order of paddy fields (51.8 3.1) > marsh (46.5 20.5) > lake (37.0 22.7) > coastal wetland (1.71 0.73). Highest atmospheric PH(3) levels in marsh are found in summer. In paddy fields, atmospheric PH(3) concentrations in flourishing stages are higher than those in slowly growing stages. PMID:21071123

  5. 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...

  6. 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

  7. Axial-ligand substitution reactions of dirhodium(II) tetraacetate with phosphines and phosphites in acetonitrile

    SciTech Connect

    Aquino, M.A.S.; Macartney, D.H.

    1987-08-12

    The kinetic and thermodynamic parameters for the axial-ligand substitution reactions of the bis(acetonitrile) adduct of dirhodium(II) tetraacetate with a variety of phosphines and phosphites in acetonitrile have been measured. The rate-determining formation of the Rh/sub 2/(O/sub 2/CCH/sub 3/)/sub 4/(CH/sub 2/CN)PR/sub 3/ adduct occurs with a rate constant that is independent of the nature of the ligand: k/sub 1/(25.0/sup 0/C) = (1.05 +/- 0.05) x 10/sup 5/ M/sup -1/ s/sup -1/, ..delta..H/sub 1//sup ++/ = 10.9 +/- 0.6 kcal mol/sup -1/, and ..delta..S/sub 1//sup ++/ = 1 +/- 2 cal K/sup -1/ mol/sup -1/. Slightly higher rate constants (1.6 x 10/sup 5/ M/sup -1/ s/sup -1/ at 25.0/sup 0/C) were found for several diphosphines (PPh/sub 2/(CH/sub 2/)/sub n/PPh/sub 2/, n = 2-4) and are attributed to the presence of two ligand coordination sites. A dissociative mechanism is proposed for substitution of the axially coordinated acetonitrile, and the rate parameters are compared with values reported for substitutions of oxygen-donor solvent molecules on the dirhodium(II) complex. The stability constants for the mono- and bisadducts have been measured at 25/sup 0/C with K/sub 1//K/sub 2/ approx. 20. The dependence of K/sub 1/ and K/sub 2/ on the nature of the phosphine or phosphite correlates well with the sigma-donor strength of the ligand, with ..pi..-acceptor strengths and steric effects being relatively insignificant.

  8. Highly sensitive determination of dialkyl phosphinate acids in environmental samples by ion chromatography tandem mass spectrometry.

    PubMed

    Niu, Yu-Min; Liang, Yong; Liu, Ji-Yan; Liu, Jing-Fu

    2015-05-15

    Dialkyl phosphinate acids (DPAs) are the hydrolysates of aluminum dialkyl phosphinates (ADPs), one class of emerging phosphorus flame retardants since brominated flame retardants have been gradually phased out in recent years. It has been found that once dissolved in water, ADPs are completely hydrolyzed and exist as DPAs. However, there is no report on the determination of DPAs in environmental water samples. For the first time, we developed a method for the analysis of trace DPAs and ADPs in different environmental samples, including waters, soils and sediments. In this proposed method, MAX cartridges were employed for the purification, and ion chromatography (IC) tandem mass spectrometry (MS) method with large volume injection (200?L) and postcolumn addition of methanol and NH3H2O were employed for the determination of DPAs and ADPs. The matrix effects were <16% for water samples and <25% for soil/sediment samples, which were greatly improved in comparison to the liquid chromatography (LC) tandem MS determination. Determined at three fortified levels of 0.02?g/L, 0.2?g/L and 1.0?g/L, the mean recoveries were from 75.8% to 110.2%, with an acceptable coefficient of variation (3.3-20%, n=6) for water samples. The limits of the method were 3.5-9.3ng/L for DPAs in environmental water samples, and 0.06-0.09?g/kg for DPAs and ADPs in soil and sediment samples. For soil and sediment samples, results determined by the present IC-MS method were in good agreement with that determined by LC-MS in our previous study. PMID:25836050

  9. 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

  10. 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

  11. Phosphine, Aerosols and Temperature Variations in Saturn's Upper Troposphere from Cassini/CIRS Observations

    NASA Astrophysics Data System (ADS)

    Fletcher, Leigh N.; Irwin, P. G.; Teanby, N. A.; Orton, G. S.; Parrish, P. D.; Calcutt, S. B.; Bowles, N.; de Kok, R.; Howett, C.; Taylor, F. W.; Cassini/CIRS Team

    2006-09-01

    Thermal infrared data from the Cassini Composite Infrared Spectrometer (CIRS, Flasar et al., 2004) has been used to produce global maps of temperature, para-hydrogen fraction, phosphine and ammonia distribution in the 60-800 mbar region with a high spatial resolution that can only be achieved by the Cassini orbiter. Since orbital insertion in July 2004, CIRS has recorded thousands of spectra in both the far (10 - 600 cm-1) and mid (600 - 1400 cm-1) infrared, at a variety of apodized spectral resolutions (0.5 - 15.0 cm-1) and viewing geometries, covering both hemispheres of the gas giant. Each of these maps will be used to discuss zonal and meridional motions within Saturn's upper troposphere. Tropospheric temperature variations are shown to occur on the same scale as the prograde and retrograde jets in Saturn's atmosphere (Porco et al., 2005), superimposed onto a much larger seasonal asymmetry. The presence of a double-lobed tropopause structure, first identified by Voyager/IRIS (Hanel et al. (1981)), which is most obvious at the northern and southern equatorial belts and more prevalent in southern summer than northern winter, will be discussed. Phosphine mapping is extended into the northern hemisphere as Cassini's orbit rises to higher inclinations, and as this is a disequilibrium species in Saturn's cold upper troposphere (Orton et al., 2000, 2001) it may be used as a tracer for the upwelling of constituent-rich air from deeper within the atmosphere. Small variations in NH3 and the para-hydrogen fraction with latitude will also be discussed in this context. Flasar, F.M. et al. (2004). Space Science Rev., 115:169-297. Hanel et al. (1981). Science, 212, 192 Orton, G.S. et al. (2000, 2001). Icarus, 146:48-59, Icarus, 149:489-490. Porco, C.C. et al. (2005). Science, 307:1243-1247. Acknowledgements: This work is funded by the UK Particle Physics and Astronomy Research council.

  12. 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.

  13. 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

  14. Azido(benzonitrile-?N)[hydridotris(pyrazol-1-yl-?N 2)borato](triphenylphosphine-?P)ruthenium(II)

    PubMed Central

    Huang, Chiung-Cheng; Chen, Han-Gung; Lo, Yih Hsing; Lai, Wen-Rong; Lin, Chia-Her

    2010-01-01

    Facile ligand substitution is observed when the rutheniumazide complex, [RuN3(Tp)(PPh3)2] [Tp,HB(pz)3, pz = pyrazolyl, PPh3 = triphenylphosphine] is treated with benzonitrile, yielding the title compound, [Ru(C9H10BN6)(N3)(C7H5N)(C18H15P)]. The asymmetric unit contains two crystallographically independent molecules. In each one, the RuII atom is six-coordinated in a distorted octahedral geometry by five N atoms from an htpb ligand, an azide ligand and a benzonitrile ligand and one P atom from a triphenylphosphine (tpp) ligand. The azide group is almost linear and is coordinated to Ru with an average RuNN angle of 124.9?(3). PMID:21587768

  15. Azido-(benzonitrile-?N)[hydrido-tris(pyrazol-1-yl-?N)borato](triphenyl-phosphine-?P)ruthenium(II).

    PubMed

    Huang, Chiung-Cheng; Chen, Han-Gung; Lo, Yih Hsing; Lai, Wen-Rong; Lin, Chia-Her

    2010-01-01

    Facile ligand substitution is observed when the ruthenium-azide complex, [RuN(3)(Tp)(PPh(3))(2)] [Tp,HB(pz)(3), pz = pyrazol-yl, PPh(3) = triphenyl-phosphine] is treated with benzo-nitrile, yielding the title compound, [Ru(C(9)H(10)BN(6))(N(3))(C(7)H(5)N)(C(18)H(15)P)]. The asymmetric unit contains two crystallographically independent mol-ecules. In each one, the Ru(II) atom is six-coordinated in a distorted octa-hedral geometry by five N atoms from an htpb ligand, an azide ligand and a benzonitrile ligand and one P atom from a triphenyl-phosphine (tpp) ligand. The azide group is almost linear and is coordinated to Ru with an average Ru-N-N angle of 124.9?(3). PMID:21587768

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

    PubMed

    Toms-Mendivil, Eder; Cadierno, Victorio; Menndez, Mara I; Lpez, Ramn

    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 ?(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

  17. 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

  18. 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.

  19. 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.

  20. Synthesis of 2-azaspiro[4.4]nonan-1-ones via phosphine-catalysed [3+2]-cycloadditions

    SciTech Connect

    Yong, Sarah R.; Williams, Morwenna C.; Pyne, Stephen G.; Ung, Alison T.; Skelton, Brian W.; White, Allan H.; Turner, Peter

    2008-10-03

    The phosphine-catalyzed [3+2]-cycloaddition of the 2-methylene {gamma}-lactams 4 and 5 and the acrylate 6 with the ylides derived from the ethyl ester, the amide or the chiral camphor sultam derivative of 2-butynoic acid (7a-c) give directly, or indirectly after reductive cyclization, spiro-heterocyclic products. The acid 32 underwent Curtius rearrangement and then acid hydrolysis to give two novel spiro-cyclic ketones, 41 and 42.

  1. 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

  2. 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

  3. 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

  4. 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.

  5. Catalytic hydrogenolysis of biphenylene with platinum, palladium, and nickel phosphine complexes

    SciTech Connect

    Edelbach, B.L.; Vicic, D.A.; Lachicotte, R.J.; Jones, W.D.

    1998-10-26

    The catalytic hydrogenolysis of biphenylene was carried out using Pt, Pd, and Ni phosphine complexes under an atmosphere of H{sub 2} between 56 and 120 C. The Pt species Pt(PEt{sub 3}){sub 3}, (PEt{sub 3}){sub 2}Pt(2,2{prime}-biphenyl), 1, trans-(PEt{sub 3}){sub 2}PtH{sub 2}, and trans-(PEt{sub 3}){sub 2}Pt({alpha}-biphenyl)H, 4, were all viable catalysts. The resting state species in each case was complex 4. At 80 C under an atmosphere of H{sub 2}, 4 reductively eliminates biphenyl and forms trans-(PEt{sub 3}){sub 2}PtH{sub 2}. Free PEt{sub 3} inhibits the rate of reductive elimination from 4 and the overall rate of hydrogenolysis. The novel Pt(IV) dihydride trans,cis-(PEt{sub 3}){sub 2}Pt(2,2{prime}-biphenyl)H{sub 2} was synthesized and characterized by X-ray analysis. trans-cis-(PEt{sub 3}){sub 2}Pt(2,2{prime}-biphenyl)H{sub 2} undergoes unimolecular reductive elimination to give 2. On the basis of these results a catalytic cycle is proposed. A mixture of [(dippe)PtH]{sub 2} and (dippe)PtH{sub 2} (dippe = bis(diisopropylphosphino)ethane) was also capable of catalyzing the hydrogenolysis of biphenylene under an atmosphere of H{sub 2} at 120 C. The rate of hydrogenolysis increases as the concentration of biphenylene, H{sub 2}, and (dippe)PtH{sub 2} increases. These observations are consistent with the C-C bond activation of biphenylene occurring via (dippe)PtH{sub 2}, not [(dippe)Pt{sup 0}]. The rate of catalytic hydrogenolysis was not affected by the length of the chelating phosphine bridge. The Ni complex [(dippe)NiH]{sub 2} was the most efficient catalyst for the hydrogenolysis of bisphenylene (16 turnovers/day at 56 C). The resting state species was (dippe)Ni(2,2{prime}-biphenyl).

  6. 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

  7. 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

  8. 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

  9. 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

  10. 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).

  11. 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.

  12. 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

  13. Toxicity of phosphine on the developmental stages of rust-red flour beetle, Tribolium castaneum Herbst over a range of concentrations and exposures.

    PubMed

    Manivannan, S

    2015-10-01

    The susceptibility of the developmental stages of rust-red flour beetle, Tribolium castaneum to a range of concentrations of phosphine over varying durations from 24 to 168h was reconnoitered in the laboratory at 25??2C. Responses of the life stages exposed to phosphine were compared with those of un-treated controls over 24, 48, 72, 96, 120, 144 and 168h exposures and mortality was assessed after 14days. Among the life stages tested, pupae were more tolerant to phosphine followed by the egg and the larval instars. At 24h, the maximum LC50 value was observed in case of egg; 1.571mgL(-1); followed by the pupae, 6(th) instar, 4(th) instar and 2(nd) instar larvae with LC50 values of 1.184, 0.336, 0.212 and 0.081mgL(-1) respectively. However, continued exposure of the developmental stages to phosphine, recorded maximum LC values in the pupae followed by egg and the larval instars. A linear increase in the mortality response was witnessed in all the insect stages when the exposure periods were extended from 24 to 168h with increasing concentrations of phosphine, conversely significant increase in mortality was greatly apparent during the initial treatment periods. PMID:26396434

  14. Synthesis of P-stereogenic diarylphosphinic amides by directed lithiation: transformation into tertiary phosphine oxides via methanolysis, aryne chemistry and complexation behaviour toward zinc(ii).

    PubMed

    Del guila-Snchez, Miguel A; Navarro, Yolanda; Garca Lpez, Jess; Guedes, Guilherme P; Lpez Ortiz, Fernando

    2016-02-01

    The highly diastereoselective synthesis of P-stereogenic phosphinic amides via directed ortho lithiation (DoLi) of (SC)-P,P-diphenylphosphinic amides with t-BuLi followed by electrophilic quench reactions is described. Functionalised derivatives containing a wide variety of ortho substituents (Cl, Br, I, OH, N3, SiMe3, SnMe3, P(O)Ph2, Me, allyl, (t)BuOCO) have been prepared in high yields with diastereomeric ratios up to 98?:?2. The X-ray diffraction structure of the ortho-stannylated and ortho-iodo compounds showed that the pro-S P-phenyl ring was stereoselectively ortho-deprotonated by the organolithium base. The usefulness of the method is supported by two key transformations, the synthesis of P-stereogenic methyl phosphinates through replacement of the chiral auxiliary by a methoxy group and the first example of the insertion of benzyne into the P-N bond of a P-stereogenic phosphinic amide. A DFT study of this reaction showed that the insertion proceeds through a [2 + 2] cycloaddition and a subsequent ring-opening with retention of the P-configuration. Explorative coordination chemistry of the new P-stereogenic ligands provided access to a chiral phosphinic amide-phosphine oxide Zn(ii) complex, the crystal structure of which is reported. PMID:26370566

  15. 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

  16. Evaluation of sorbent materials for the sampling and analysis of phosphine, sulfuryl fluoride and methyl bromide in air.

    PubMed

    Magnusson, R; Rittfeldt, L; stot, C

    2015-01-01

    Phosphine (PH3), sulfuryl fluoride (SO2F2) and methyl bromide (CH3Br) are highly toxic chemical substances commonly used for fumigation, i.e., pest control with gaseous pesticides. Residues of fumigation agents constitute a health risk for workers affected, and therefore accurate methods for air sampling and analysis are needed. In this study, three commercial adsorbent tubes; Carbosieve SIII, Air Toxics and Tenax TA, were evaluated for sampling these highly volatile chemicals in air and their subsequent analysis by thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS). The breakthrough volume (BTV) of each fumigant was experimentally determined on the different adsorbents at concentrations at or above their permissible exposure limits, using a method based on frontal chromatography of generated fumigant atmospheres. Carbosieve SIII, a molecular sieve possessing a very high specific area, proved to be a better adsorbent than both Air Toxics and Tenax TA, resulting in at least a 4-fold increase of the BTV50%. BTV50% for Carbosieve SIII at 20C was measured as 4.7L/g, 5.5L/g and 126L/g for phosphine, sulfuryl fluoride and methyl bromide, respectively, implying safe sampling volumes of 1.9L, 2.2L and 50L, respectively, for a commercial tube packed with 800mg Carbosieve SIII. The temperature dependence of BTV was strong for Carbosieve SIII, showing a reduction of 3-5%/C in breakthrough volume within the range -20 to 40C. Furthermore, although Carbosieve SIII reportedly has a higher affinity for water than most other adsorbents, relative humidity had only a moderate influence on the retention capacity of phosphine. Overall, the applicability of Carbosieve SIII adsorbent sampling in combination with TD-GC-MS analysis was demonstrated for highly volatile fumigants. PMID:25512126

  17. 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

  18. Influence of environmental, structural, and behavioral factors on the presence of phosphine in worker areas during fumigations in grain elevators.

    PubMed

    Reed, C

    2001-02-01

    Data-logging gas monitors with electrochemical cells sensitive to phosphine (PH3) were used to characterize concentrations of this common grain fumigant in and around grain elevators during fumigations. Twenty-four grain fumigations were observed, and each was monitored over a 5- to 8-day period. Phosphine gas, generated from aluminum phosphide fumigant applied to the grain, generally moved upward toward the grain surface and exited the bin at bin-top openings to the outside air or to enclosed worker areas. The upward air currents appeared to be the result of chimney effects, e.g., pressure differences resulting from buoyant air inside the warm grain and cooler, denser, ambient air. Significant wind effects on the PH3 concentration were also observed in the air between the grain surface and the bin roof. In enclosed areas located at the bin-top level, monitors located near the fill port or the fumigant dispenser recorded PH3 concentrations in excess of the exposure limit of 0.3 parts per million (ppm) about 35% of the time during grain fumigations. Phosphine concentrations between 0.31 and 1.0 ppm were observed 17.3% of the time, and concentrations in the ranges of 1.01-3.0, 3.01-10.0, and >10 ppm constituted 11.8%, 5.5%, and 0.3% of all readings, respectively, in bin-top worker areas. The likelihood of recording PH3 concentrations >0.3 ppm depended on ventilation practices. Fans in tunnels and open windows at aboveground locations appeared to greatly reduce the likelihood of high PH3 concentrations in enclosed areas. PMID:11398899

  19. Synthesis, Structure, and Magnetism of Mono- and Binuclear Manganese(II) Compounds of Nitronyl Nitroxide Substituted Phosphine Oxides.

    PubMed

    Rancurel, Corinne; Leznoff, Daniel B.; Sutter, Jean-Pascal; Golhen, Stphane; Ouahab, Lahcne; Kliava, Janis; Kahn, Olivier

    1999-10-18

    Complexes of manganese(II)-containing aminoxyl radical substituted phosphine oxide ligands are reported. The compounds [(o-nitronyl nitroxide-phenyl)diphenylphosphine oxide]bis(hexafluoroacetylacetonato)manganese(II), 3, and bis{[(p-nitronyl nitroxide-phenyl) diphenylphosphine oxide]bis(hexafluoroacetylacetonato)manganese(II)}, 4, prepared by addition of the free radical phosphine oxides to Mn(hfac)(2), were structurally characterized. Complex 3 is mononuclear, containing an O,O-chelating ortho-substituted radical phosphine oxide ligand, while in 4 the para-substituted ligands bridge two Mn(hfac)(2) units to yield a binuclear molecular rectangle. The magnetic behavior of both systems is dominated by a strong antiferromagnetic Mn(II)-aminoxyl interaction (J = -213 (3), -218 (4) cm(-)(1) with H = -JS(Mn).S(rad)) to give effective S = 2 ground state units. The S = 3 excited state is populated at high temperatures. At low temperatures a decrease in chi(M)T in both complexes is attributable primarily to inter- or intramolecular antiferromagnetic interactions rather than zero-field splitting (ZFS) of the S = 2 ground state. For the bimetallic compound, the magnetic data indicate that ligand-mediated interactions between the Mn(II) spin carriers are weak. The powder EPR spectra of both systems have been recorded and successfully simulated, giving a ZFS parameter D = 0.112 cm(-)(1). Crystals of 3 are triclinic, space group P&onemacr; with a = 10.6672(19) , b = 13.270(6) , c = 15.363(3) , alpha = 93.84(2) degrees, beta = 108.054(16) degrees, gamma = 105.69(3) degrees, and Z = 2. Crystals of 4 are monoclinic, space group P2(1)/a with a = 12.463(6) , b = 19.315(3) , c = 17.084(9) , alpha = 90 degrees, beta = 98.49(2) degrees, gamma = 90 degrees, and Z = 2. PMID:11671201

  20. 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

  1. 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.

  2. 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.

  3. The influence of the combination of carboxylate and phosphinate pendant arms in 1,4,7-triazacyclononane-based chelators on their 68Ga labelling properties.

    PubMed

    Mt, Gbor; ime?ek, Jakub; Pniok, Miroslav; Kertsz, Istvn; Notni, Johannes; Wester, Hans-Jrgen; Galuska, Lszl; Hermann, Petr

    2015-01-01

    In order to compare the coordination properties of 1,4,7-triazacyclononane (tacn) derivatives bearing varying numbers of phosphinic/carboxylic acid pendant groups towards 68Ga, 1,4,7-triazacyclononane-7-acetic-1,4-bis(methylenephosphinic) acid (NOPA) and 1,4,7- triazacyclononane-4,7-diacetic-1-[methylene(2-carboxyethyl)phosphinic] acid (NO2AP) were synthesized using Mannich reactions with trivalent or pentavalent forms of H-phosphinic acids as phosphorus components. Stepwise protonation constants logK1-3 12.06, 3.90 and 1.95, and stability constants with GaIII and CuII, logKGaL 24.01 and logKCuL 16.66, were potentiometrically determined for NOPA. Both ligands were labelled with 68Ga and compared with NOTA (tacn-N,N',N?-triacetic acid) and NOPO, a TRAP-type [tacn-N,N',N?- tris(methylenephosphinic acid)] chelator. At pH 3, NOPO and NOPA showed higher labelling efficiency (binding with lower ligand excess) at both room temperature and 95 C, compared to NO2AP and NOTA. Labelling efficiency at pH = 0-3 correlated with a number of phosphinic acid pendants: NOPO > NOPA > NO2AP > NOTA; however, it was more apparent at 95 C than at room temperature. By contrast, NOTA was found to be labelled more efficiently at pH > 4 compared to the ligands with phosphinic acids. Overall, replacement of a single phosphinate donor with a carboxylate does not challenge 68Ga labelling of TRAP-type chelators. However, the presence of carboxylates facilitates labelling at neutral or weakly acidic pH. PMID:26197305

  4. 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

  5. Phosphine-induced oxidative stress in Hepa 1c1c7 cells.

    PubMed

    Hsu, C H; Quistad, G B; Casida, J E

    1998-11-01

    Phosphine (PH3), from hydrolysis of metal phosphides, is an important insecticide (aluminum phosphide) and rodenticide (zinc phosphide) and is considered genotoxic and cytotoxic in mammals. This study tests the hypothesis that PH3-induced genotoxicity and cytotoxicity are associated with oxidative stress by examining liver (Hepa 1c1c7) cells for possible relationships among cell death, increases in reactive oxygen species (ROS) and lipid peroxidation, and elevated 8-hydroxyguanine (8-OH-Gua) in DNA. PH3 was generated from 0.5 mM magnesium phosphide (Mg3P2) to give 1 mM PH3 as the nominal and maximal concentration. This level causes 31% cell death at 6 h, measured by lactate dehydrogenase leakage, with appropriate dependence on concentration and time. The intracellular ROS level is elevated within 0.5 h following exposure to PH3, peaking at 235% of the control by about 1 h. Lipid peroxidation (measured as malondialdehyde plus 4-hydroxyalkenals) is increased up to 504% by PH3 at 6 h in a time-dependent manner. The level of 8-OH-Gua in DNA, a biomarker of mutagenic oxidative DNA damage analyzed by GC/MS, increases to 259% at 6 h after PH3 treatment. Antioxidants significantly attenuate the PH3-induced ROS formation, lipid peroxidation, 8-OH-Gua formation in DNA, and cell death, with the general order for effectiveness of GSH (5 mM) and D-mannitol (10 mM) (hydroxyl radical scavengers), then Tempol (2.5 mM) and sodium azide (3 mM) (superoxide anion and singlet oxygen scavengers, respectively). These studies support the hypothesis that PH3-induced mutagenic and cytotoxic effects are due to increased ROS levels, probably hydroxyl radicals, initiating oxidative damage. PMID:9928684

  6. 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

  7. 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 phosphineborane 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 1M 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 (1M vs. 4mM, 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

  8. Spectroscopic and magnetic properties of an iodo Co(I) tripodal phosphine complex.

    PubMed

    Rose, Michael J; Bellone, Donatela E; Di Bilio, Angel J; Gray, Harry B

    2012-10-14

    Reaction of the tripodal phosphine ligand 1,1,1-tris((diphenylphosphino)phenyl)ethane (PhP3) with CoI(2) spontaneously generates a one-electron reduced complex, [(PhP3)Co(I)(I)] (1). The crystal structure of 1 reveals a distorted tetrahedral environment, with an apical Co-I bond distance of ~2.52 . Co(II/I) redox occurs at an unusually high potential (+0.38 V vs. SCE). The electronic absorption spectrum of 1 exhibits an MLCT peak at 320 nm (? = 8790 M(-1) cm(-1)) and a d-d feature at 850 nm (? = 840 M(-1) cm(-1)). Two more d-d bands are observed in the NIR region, 8650 (? = 450) and 7950 cm(-1) (? = 430 M(-1) cm(-1)). Temperature dependent magnetic measurements (SQUID) on 1 (solid state, 20-300 K) give ?(eff) = 2.99(6) ?(B), consistent with an S = 1 ground state. Magnetic susceptibilities below 20 K are consistent with a zero field splitting (zfs) |D| = 8 cm(-1). DFT calculations also support a spin-triplet ground state for 1, as optimized (6-31G*/PW91) geometries (S = 1) closely match the X-ray structure. EPR measurements performed in parallel mode (X-band; 0-15,000 G, 15 K) on polycrystalline 1 or frozen solutions of 1 (THF/toluene) exhibit a feature at g? 4 that arises from a (?m = 2) transition within the M(S) = <+1,-1> manifold. Below 10 K, the EPR signal decreases significantly, consistent with a solution zfs parameter (|D|? 8 cm(-1)) similar to that obtained from SQUID measurements. Our work provides an EPR signature for high-spin Co(I) in trigonal ligation. PMID:22903546

  9. 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.

  10. 31P{1H}NMR and carbonyl force constants of unsymmetrical bidentate phosphine complexes of group (VI) metal carbonyls

    NASA Astrophysics Data System (ADS)

    Jesu Raj, Joe Gerald; Pathak, Devendra Deo; Kapoor, Pramesh N.

    2015-05-01

    In our present work we report synthesis of an unsymmetrical diphos ligand, 1-diphenylphosphino-2-di-m-tolylphosphinoethane and its coordinate complexes with group (VI) metal carbonyls such as Cr(CO)6 Mo(CO)6 and W(CO)6. The synthesized ligand and its complexes have been completely characterized by elemental analyses, FTIR, 1HNMR, 31P{1H}NMR and FAB mass spectrometry methods. Special emphasis has been given to calculations of carbonyl force constants. Based on the spectroscopic evidences it has been confirmed that these metal carbonyl complexes with the ditertiary phosphine ligand showed cis geometry in their molecular structure.

  11. Synthesis, structures and anti-malaria activity of some gold(I) phosphine complexes containing seleno- and thiosemicarbazonato ligands.

    PubMed

    Molter, Anja; Rust, Jrg; Lehmann, Christian W; Deepa, Ganesh; Chiba, Peter; Mohr, Fabian

    2011-10-14

    A series of both mono- and dinuclear gold(I) phosphine complexes containing monoanionic seleno- and thiosemicarbazones as ligands were prepared and fully characterized by spectroscopic methods and, in some cases, by single crystal X-ray diffraction. The in vitro anti-malaria activity of some of these compounds was investigated in chloroquine sensitive strains of Plasmodium falciparum. The IC(50) results show that the sulfur containing compounds exhibit activity similar to that of chloroquine, whilst the selenium derivatives display only moderate anti-malaria activity. PMID:21879088

  12. 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

  13. 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

  14. Vinylarene/CO copolymerization and vinylarene/polar vinyl monomer/CO terpolymerization using palladium/phosphine-sulfonate catalysts.

    PubMed

    Kageyama, Takeharu; Ito, Shingo; Nozaki, Kyoko

    2011-02-01

    Palladium/phosphine-sulfonate complexes were effective for the alternating copolymerization of vinylarenes with carbon monoxide (CO). The obtained copolymers had iso-enriched microstructures with ll selectivity of up to circa 60%. The catalytic system was successfully applied to the terpolymerization of vinylarene and polar vinyl monomers with CO to produce novel terpolymers, which could not be obtained by using previously developed catalysts. NMR and DSC analyses suggested that vinylarene/CO units and polar vinyl monomer/CO units were randomly distributed in the terpolymer main chains. PMID:21254443

  15. 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

  16. Sodium phenoxide-phosphine oxides as extremely active Lewis base catalysts for the Mukaiyama aldol reaction with ketones.

    PubMed

    Hatano, Manabu; Takagi, Eri; Ishihara, Kazuaki

    2007-10-25

    A highly efficient Mukaiyama aldol reaction between ketones and trimethylsilyl enolates catalyzed by sodium phenoxide-phosphine oxides as simple homogeneous Lewis base catalysts (0.5-10 mol %) was developed, which minimized competing retro-aldol reaction. For a variety of aromatic ketones and aldimines, aldol and Mannich-type products with an alpha-quaternary carbon center were obtained in good to excellent yields. Up to 100 mmol scale of benzophenone and trimethylsilyl enolate with 0.5 mol % of catalyst was established in 97% yield (34.8 g). PMID:17894505

  17. 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

  18. 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

  19. Molecular structures of some tertiary phosphine betaines in their crystalline adducts

    NASA Astrophysics Data System (ADS)

    Li, Song-Lin; Mak, Thomas C. W.

    1996-10-01

    Direct reaction of Ph 3P and Ph 2P(CH 2) 2PPh 2 with acrylic acid in AcOEt-acetone yielded the tertiary phosphine betaine triphenylphosphoniopropionate, Ph 3P +(CH 2) 2CO -2 (L 1), and the novel double betaine ethylenebis(diphenylphosphoniopropionate) -O 2C(CH 2) 2Ph 2P +(CH 2) 2Ph 2P +(CH 2) 2CO -2(L 2), respectively. Reaction of Ph 3P with fumaric acid in AcOEt/acetone did not afford the corresponding betaine derivative Ph 3P +CH(CO 2H)CH 2CO -2, but decarboxylates to L 1 in situ. Four adducts of L 1, L 2 and Ph 3P +(CH 2) 3CO -2 (L 3) have been prepared and characterized by single-crystal X-ray analysis. In L 12H 2O, 1, two betaine molecules are joined by donor hydrogen bonds from solvated H 2O molecules to form ten-membered rings which are further linked by hydrogen bonds to form chains extending parallel to [1 0 0]. In (HL 1) 2(O 2CCH?CHCO 2)HO 2CCH?CHCO 2H2H 2O, 2, the fumaric acid molecules, fumarate anions and water molecules are interlinked by hydrogen bonds to form layers with an interlayer separation of {1}/{c}? = 10.713(4) ; the HL 1 cations are sandwiched between adjacent layers and connected to them through hydrogen bonding. In L 2(CH 3) 2CO5H 2O, 3, two independent L 2 molecules adopt different orientations and are cross-linked by hydrogen bonds with the water molecules to form layers with an interlayer spacing of {1}/{a}? = 10.341(a) ; the (CH 3) 2CO molecules are sandwiched between adjacent layers. In [(HL 3) 2(NO 3)]NO 3, 4, two independent HL 3 cations are joined by one of the NO -3 group to form a dimeric cation.

  20. 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.

  1. Tuning the depth of bowl-shaped phosphine hosts: capsule and pseudo-cage architectures in host-guest complexes with C60 fullerene.

    PubMed

    Yamamura, Masaki; Sukegawa, Kimiya; Nabeshima, Tatsuya

    2015-08-01

    Bowl-shaped phosphine molecules, whose bowl geometry can be controlled by a variation of the axial substituent, were synthesized, and used as host molecules to encapsulate C60. Host molecules with relatively shallow bowls formed a chiral capsule, while hosts with deeper bowls formed an achiral pseudo-cage. PMID:26120943

  2. A Stereoselective Synthesis of Phosphinic Acid Phosphapeptides Corresponding to Glutamyl-?-glutamate and Incorporation into Potent Inhibitors of Folylpoly-?-glutamyl Synthetase

    PubMed Central

    Bartley, David M.; Coward, James K.

    2007-01-01

    Radical addition of H3PO2 to N-/C-protected vinyl glycine led to the corresponding H-phosphinic acid in excellent yield. The non-nucleophilic H-phosphinic acid was converted to a nucleophilic PIII species, RP(OTMS)2, which was used in two approaches to the target phosphinic acid containing pseudopeptide. New methodology was developed that led to excellent yields in the reaction of RP(OTMS)2 with unactivated electrophiles, including an acyclic homoallylic bromide. However, en route to the target pseudopeptide, Arbuzov reaction of RP(OTMS)2 with a cyclic homoallylic bromide, (R)-3-(bromomethyl)-cyclopent-1-ene, led to a rearranged allylic phosphinic acid rather than the desired homoallylic derivative, a putative glutarate surrogate. Conjugate addition of RP(OTMS)2 to ?-methylene glutarate containing a chiral auxiliary resulted in only modest diastereoselectivity. Purification by flash chromatography provided protected derivatives of both diastereomers of the pseudopeptide. Following global deprotection, coupling of (S)-H-Glu-?[?(P(O)(OH)(CH2))]-(S)-Glu- OH and (S)-H-Glu-?-[?(P(O)(OH)(CH2))]-(R)-Glu-OH to (4-amino-4-deoxy-10-methyl)pteroyl azide led to the target compounds for biochemical study as inhibitors of the ATP-dependent ligase, folylpoly-?-glutamate synthetase. PMID:16095295

  3. 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.

  4. A facile phosphine-free colloidal synthesis of Cu2SnS3 and Cu2ZnSnS4 nanorods with a controllable aspect ratio.

    PubMed

    Wang, Jian-Jun; Liu, Pai; Ryan, Kevin M

    2015-09-18

    Cu2SnS3 (CTS) nanorods were synthesized with a controllable aspect ratio via a facile phosphine-free colloidal synthesis. This synthesis can be readily extended to obtain Cu2ZnSnS4 (CZTS) nanorods with tunable Zn content. PMID:26235602

  5. 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

  6. REACTIONS OF {eta}{sup 5}-CYCLOPENTADIENYLCOBALT(III) ALKYLS WITH COBALT(I) PHOSPHINES AND IRON CARBONYLS. EVIDENCE FOR DIRECT {eta}{sup 5} -CYCLOPENTADIENYL AND TRIMETHYLPHOSPHINE GROUP TRANSFER BETWEEN METAL CENTERS

    SciTech Connect

    Bryndza, H.E.; Bergman, R.G.

    1980-08-01

    We have found that {eta}{sup 5}-methylcyclopentadienyl- (triphenylphosphine)dimethylcobalt(III) (1) undergoes intermolecular cyclopentadienyl ligand exchange with {eta}{sup 5}-cyclopentadienylbistriphenylphosphinecobalt(I). The unsubstituted cyclopentadienyl(triphenylphosphine)dimethylco-balt(III) undergoes exchange of phosphine for carbon monoxide with both Fe(CO){sub 4} and Fe(CO){sub 5} by two different mechanisms. The first involves electrophilic displacement of coordinated phosphine by unsaturated Fe(CO){sub 4} and the second takes place by electrophilic displacement of CO from Fe(CO){sub 5} by the unsaturated CpCoMe{sub 2} fragment (generated by phosphine dissociation from the saturated starting material).

  7. Hydrogen Peroxide and Di(hydroperoxy)propane Adducts of Phosphine Oxides as Stoichiometric and Soluble Oxidizing Agents.

    PubMed

    Ahn, Shin Hye; Cluff, Kyle J; Bhuvanesh, Nattamai; Blmel, Janet

    2015-11-01

    Aqueous hydrogen peroxide is widely used as an oxidizing agent in industry and academia. Herein, the hydrogen peroxide adducts of phosphine oxides, [tBu3 PO?H2 O2 ]2 and [Ph3 PO?H2 O2 ]2 ?H2 O2 , are described. Additionally, the corresponding di(hydroperoxy)propane adducts R3 PO?(HOO)2 CMe2 (R=Cy, Ph) were synthesized and characterized. All adducts could be obtained as large single crystals suitable for structural characterization by X-ray crystallography and solid-state NMR spectroscopy. The di(hydroperoxy)propane adducts are soluble in organic solvents which enables oxidation reactions in one phase. As the adducts are solid and molecular, they can easily be applied stoichiometrically. No loss of oxidizing power occurs upon long-term storage of the single crystals at room temperature or the powders at -20?C. PMID:26457679

  8. 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

  9. 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.

  10. 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.

  11. 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

  12. 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

  13. Facile Phosphine-Free Synthesis of CdSe/ZnS Core/Shell Nanocrystals Without Precursor Injection.

    PubMed

    Zhu, Chang-Qing; Wang, Peng; Wang, Xin; Li, Yan

    2008-01-01

    A new simple method for synthesis of core/shell CdSe/ZnS nanocrystals (NCs) is present. By adapting the use of cadmium stearate, oleylamine, and paraffin liquid to a non-injection synthesis and by applying a subsequent ZnS shelling procedure to CdSe NCs cores using Zinc acetate dihydrate and sulfur powder, luminescent CdSe/ZnS NCs with quantum yields of up to 36% (FWHM 42-43 nm) were obtained. A seeding-growth technique was first applied to the controlled synthesis of ZnS shell. This method has several attractive features, such as the usage of low-cost, green, and environmentally friendlier reagents and elimination of the need for air-sensitive, toxic, and expensive phosphines solvent. Furthermore, due to one-pot synthetic route for CdSe/ZnS NCs, the approach presented herein is accessible to a mass production of these NCs. PMID:21777485

  14. Facile Phosphine-Free Synthesis of CdSe/ZnS Core/Shell Nanocrystals Without Precursor Injection

    NASA Astrophysics Data System (ADS)

    Zhu, Chang-Qing; Wang, Peng; Wang, Xin; Li, Yan

    2008-06-01

    A new simple method for synthesis of core/shell CdSe/ZnS nanocrystals (NCs) is present. By adapting the use of cadmium stearate, oleylamine, and paraffin liquid to a non-injection synthesis and by applying a subsequent ZnS shelling procedure to CdSe NCs cores using Zinc acetate dihydrate and sulfur powder, luminescent CdSe/ZnS NCs with quantum yields of up to 36% (FWHM 42 43 nm) were obtained. A seeding-growth technique was first applied to the controlled synthesis of ZnS shell. This method has several attractive features, such as the usage of low-cost, green, and environmentally friendlier reagents and elimination of the need for air-sensitive, toxic, and expensive phosphines solvent. Furthermore, due to one-pot synthetic route for CdSe/ZnS NCs, the approach presented herein is accessible to a mass production of these NCs.

  15. Mechanistic studies on the formation of linear polyethylene chain catalyzed by palladium phosphine-sulfonate complexes: experiment and theoretical studies.

    PubMed

    Noda, Shusuke; Nakamura, Akifumi; Kochi, Takuya; Chung, Lung Wa; Morokuma, Keiji; Nozaki, Kyoko

    2009-10-01

    Linear polyethylene propagation starting from Pd phosphine-sulfonate complexes, Pd(CH(3))(L)(Ar(2)PC(6)H(4)SO(3)) (L = 2,6-lutidine, Ar = o-MeOC(6)H(4) (2a) and L = pyridine, Ar = Ph (2b)), was studied both experimentally and theoretically. Experimentally, highly linear polyethylene was obtained with Pd(CH(3))(L)(Ar(2)PC(6)H(4)SO(3)) complexes 2a and 2b. Formation of a long alkyl-substituted palladium complex (3) was detected as a result of ethylene oligomerization on a palladium center starting from methylpalladium complex. Additionally, well-defined ethyl and propyl complexes (6(Et) and 6(Pr)) were synthesized as stable n-alkyl palladium complexes. In spite of the existence of beta-hydrogens, the beta-hydride elimination to give 1-alkenes was very slow or negligible in all cases. On the other hand, isomerization of 1-hexene in the presence of a methylpalladium/phosphine-sulfonate complex 2a indicated that this catalyst system actually undergoes beta-hydride elimination and reinsertion to release internal alkenes. On the theoretical side, the relative energies were calculated for intermediates and transition states for chain-growth, chain-walking, and chain-transfer on the basis of the starting model complex Pd(n-C(3)H(7))(pyridine)(o-Me(2)PC(6)H(4)SO(3)) (8). First, cis/trans isomerization process via the Berry's pseudorotation was proposed for the Pd/phosphine-sulfonate system. The second oxygen atom of sulfonate group is involved in the isomerization process as the associative ligand, which is one of the most unique natures of the sulfonate group. Chain propagation was suggested to take place from the less stable alkylPd(ethylene) complex 10' with the TS of 27.4/27.7 ((E+ZPC)/G) kcal/mol. Possible beta-hydride elimination was suggested to occur under low concentration of ethylene: the highest-energy transition state to override for beta-hydride elimination was either >37.4/25.3 kcal/mol (TS(9-12)) or 29.1/27.4 kcal/mol (TS(8'-9') to reach 12'). The ethylene insertion to the iso-alkylpalladium species (14') is allowed via a TS of 28.6/29.1 kcal/mol (TS(14'-15')), slightly higher in energy than that for the normal-alkylpalladium species (TS(10'-11')). Easy chain transfer was suggested to proceed from the more stable PdH(olefin) complex 12' if beta-hydride elimination to 12' does take place. Thus, the production of linear polyethylene with high molecular weight under ethylene pressure suggests that the cis and trans PdH(alkene)(phosphine-sulfonate) complexes (12 and 12') are merely accessible in the presence of excess amount of ethylene. PMID:19746977

  16. 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

  17. 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

  18. 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.

  19. Phosphine-stabilised Au? clusters interacting with titania and silica surfaces: the first evidence for the density of states signature of the support-immobilised cluster.

    PubMed

    Andersson, Gunther G; Golovko, Vladimir B; Alvino, Jason F; Bennett, Trystan; Wrede, Oliver; Mejia, Sol M; Al Qahtani, Hassan S; Adnan, Rohul; Gunby, Nathaniel; Anderson, David P; Metha, Gregory F

    2014-07-01

    Chemically made, atomically precise phosphine-stabilized clusters Au9(PPh3)8(NO3)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 Au9 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. PMID:25005298

  20. Molybdenum complexes supported by mixed NHC/phosphine ligands: activation of N2 and reaction with P(OMe)3 to the first meta-phosphite complex.

    PubMed

    Gradert, Christian; Stucke, Nadja; Krahmer, Jan; Nther, Christian; Tuczek, Felix

    2015-01-12

    Molybdenum(0) dinitrogen complexes, supported by the mixed NHC/phosphine pincer ligand PCP, exhibit an extreme activation of the N2 ligand due to a very ?-electron-rich metal center. The low thermal stability of these compounds can be increased using phosphites instead of phosphines as coligands. Through an amalgam reduction of [MoCl3(PCP)] in the presence of trimethyl phosphite and N2 the highly activated and room-temperature stable dinitrogen complex [Mo(N2)(PCP)(P(OMe)3)2] is obtained. As a second product, the first transition metal complex containing the meta-phosphite ligand P(O)(OMe) originates from this reaction. PMID:25413972

  1. An Electronic Rationale for Observed Initiation Rates in Ruthenium-Mediated Olefin Metathesis: Charge Donation in Phosphine And N-Heterocyclic Carbene Ligands

    SciTech Connect

    Getty, K.; Delgado-Jaime, M.U.; Kennepohl, P.

    2009-06-01

    Ru K-edge XAS data indicate that second generation ruthenium-based olefin metathesis precatalysts (L = N-heterocyclic carbene) possess a more electron-deficient metal center than in the corresponding first generation species (L = tricyclohexylphosphine). This surprising effect is also observed from DFT calculations and provides a simple rationale for the slow phosphine dissociation kinetics previously noted for second-generation metathesis precatalysts.

  2. Conformational and solvation studies via computer simulation of the novel large scale diastereoselectively synthesized phosphinic MMP inhibitor RXP03 diluted in selected solvents.

    PubMed

    Matziari, Magdalini; Dellis, Dimitris; Dive, Vincent; Yiotakis, Athanasios; Samios, Jannis

    2010-01-14

    Structure-activity relationship studies, regarding the influence of side chains of phosphinic pseudotripeptidic inhibitors on matrix metalloproteinases (MMPs), provided potent and selective inhibitors for this family of structurally and functionally related proteases. Among them, phosphinic pseudopeptide CbzPhepsi[P(O)(OH)CH(2)] phenylpropyl TrpNH(2), known as RXP03, has been extensively used for in vivo and in vitro studies so far. The large quantities of RXP03 required for in vivo studies, as well as the necessity for diastereoisomeric purity, motivated us to further explore and develop an efficient synthetic methodology, which allows separation of the four diastereoisomers of RXP03 based on the astonishing observed differences in solubility of the four isomers in various solvents. This fact prompted us to examine theoretically the conformational differences of these four isomers via computer simulations in the solvents used experimentally. Given the fact that the four examined diastereoisomeric forms of the phosphinic peptides exhibit different behavior in terms of potency and selectivity profiles toward zinc-metalloproteases, this theoretical study provides valuable information on the conformation of phosphinic inhibitors and therefore improves the design and synthesis of active structures. The differences in solubility of RXP03 diastereoisomers in the used solvents were examined in terms of intra- and intermolecular structure. It is found that the different solubility of the RRS and RSS diastereoisomers in EtOH is a result of the different number of hydrogen bonds formed by each isomer with EtOH molecules. In the case of SRS and SSS in Et(2)O, their different solubility might be attributed to the different intramolecular hydrogen bonds formed on these diastereoisomers. PMID:20014753

  3. Crystal structure of poly[(?3-thiocyanato-?3 N:S:S)(trimethylphosphine sulfide-?S)copper(I)

    PubMed Central

    Corfield, Peter W. R.

    2014-01-01

    In the title compound, [Cu(NCS)(C3H9PS)]n, the thiocyanate ions bind the CuI atoms covalently, forming infinite CuSCNCu chains parallel to the a axis. Each CuI atom is also coordinated to a trimethylphosphine sulfide group via a CuS bond. Two crystallographically independent chains propagate in opposite directions, and are held together in a ribbon arrangement by long bonds between CuI atoms in the first chain and thiocyanate S atoms in the second, with CuS = 2.621?(1)?. The geometry around the CuI atoms in the first chain is distorted tetrahedral, with angles involving the long CuS bond much less than ideal, and the SCuN angle between the phosphine sulfide S atom and the thiocyanate N atom opening out to 133.19?(9). Each CuI atom in the second chain appears to be disordered between two positions 0.524?(4)? apart, with occupancy factors of 0.647?(6) and 0.353?(6). The CuI atom in the major site is in a distorted trigonalplanar configuration, with the SCuN angle between the phosphine sulfide and the thiocyanate N atom again opened out, to 137.01?(15). The CuI atom in the minor site, however, forms in addition a long bond [CuS = 2.702?(5)?] to the phosphine sulfide of the first chain, not the thiocyanate S atom, to provide a further link between the chains. PMID:25484723

  4. Utility of Bifunctional N-Heterocyclic Phosphine (NHP)-Thioureas for Metal-Free Carbon-Phosphorus Bond Construction toward Regio- and Stereoselective Formation of Vinylphosphonates.

    PubMed

    Mulla, Karimulla; Aleshire, Kyle L; Forster, Paul M; Kang, Jun Yong

    2016-01-01

    An efficient and practical protocol for completely regioselective and highly stereoselective synthesis of vinyldiazaphosphonates from N-heterocyclic phosphine (NHP) and allenes via phospha-Michael/intramolecular nucleophilic substitution reaction has been developed. This transformation enabled the synthesis of valuable densely functionalized vinyldiazaphosphonates with a ?-, ?-unsaturated ester moiety under mild reaction conditions. Synthetic utility of vinyldiazaphosphonates was demonstrated by a series of synthetic manipulations. PMID:26639442

  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 ?-? excitations previously shown for coinage metal cyanide chains. PMID:24840102

  6. Tris(3-hydroxypropyl)phosphine (THPP): A mild, air-stable reagent for the rapid, reductive cleavage of small-molecule disulfides.

    PubMed

    McNulty, James; Krishnamoorthy, Venkatesan; Amoroso, Dino; Moser, Michael

    2015-10-01

    Tris(3-hydroxypropyl)phosphine (THPP) is demonstrated to be a versatile, water-soluble and air-stable reducing agent, allowing for the rapid, irreversible reductive cleavage of disulfide bonds in both aqueous and buffered aqueous-organic media. The reagent shows exceptional stability at biological pH under which condition it permits the rapid reduction of a wide range of differentially functionalized small-molecule disulfides. PMID:26318995

  7. 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

  8. 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.

  9. In vitro antitumour activity of water soluble Cu(I), Ag(I) and Au(I) complexes supported by hydrophilic alkyl phosphine ligands.

    PubMed

    Santini, Carlo; Pellei, Maura; Papini, Grazia; Morresi, Barbara; Galassi, Rossana; Ricci, Simone; Tisato, Francesco; Porchia, Marina; Rigobello, Maria Pia; Gandin, Valentina; Marzano, Cristina

    2011-02-01

    Hydrophilic, monocationic [M(L)(4)]PF(6) complexes (M = Cu or Ag; L: thp = tris(hydroxymethyl)phosphine, L: PTA = 1,3,5-triaza-7-phosphaadamantane, L: thpp = tris(hydroxypropyl)phosphine) were synthesized by ligand exchange reaction starting from [Cu(CH(3)CN)(4)]PF(6) or AgPF(6) precursors at room temperature in the presence of an excess of the relevant phosphine. The related [Au(L)(4)]PF(6) complexes (L = thp, PTA or thpp) were synthesized by metathesis reactions starting from [Au(L)(4)]Cl at room temperature in the presence of equimolar quantity of TlPF(6). The three series of complexes [M(L)(4)]PF(6) were tested as cytotoxic agents against a panel of several human tumour cell lines also including a defined cisplatin resistant cell line. These investigations have been carried out in comparison with the clinically used metallodrug cisplatin and preliminary structure-activity relationships are presented. The best results in terms of in vitro antitumour activity were achieved with metal-thp species and, among the coinage metal complexes, copper derivatives were found to be the most efficient drugs. Preliminary studies concerning the mechanism of action of these [M(L)(4)]PF(6) species pointed to thioredoxin reductase as one of the putative cellular targets of gold and silver complexes and provided evidence that copper derivatives mediated their cytotoxic effect through proteasome inhibition. PMID:21194623

  10. Occurrence of matrix-bound phosphine in polar ornithogenic tundra ecosystems: effects of alkaline phosphatase activity and environmental variables.

    PubMed

    Zhu, Renbin; Ma, Dawei; Ding, Wei; Bai, Bo; Liu, Yashu; Sun, Jianjun

    2011-09-01

    Phosphine (PH(3)), a reduced phosphorus compound, is a highly toxic and reactive atmospheric trace gas. In this study, a total of ten ornithogenic soil/sediment profiles were collected from tundra ecosystems of east Antarctica and Arctic, and matrix-bound phosphine (MBP), the phosphorus fractions and alkaline phosphatase activity (APA) were analyzed. High MBP concentrations were found in these profiles with the range from 39.59 ng kg(-1) dw to 11.77 ?g kg(-1) dw. MBP showed a consistent vertical distribution pattern in almost all the soil profiles, and its concentrations increased at soil surface layers and then decreased with depths. MBP levels in the ornithogenic soils were two to three orders of magnitude lower than those in ornithogenic sediments. The yield of PH(3) as a fraction of total P in all the profiles ranged from 10(-5) to 10(-9) mgPH(3) mg(-1)P with higher mean PH(3) yield in the ornithogenic sediments. The ornithogenic soils showed high concentrations of total phosphorus (TP), organic phosphorus (OP), inorganic phosphorus (IP) and metal elements (Cu, Zn, Mn, Fe, Al and Ca) but low MBP levels, vice versa for the ornithogenic sediments. No correlation had been obtained between MBP concentrations and IP, OP and TP. There existed an exponential correlation (r=0.67, p<0.01) between MBP and soil/sediment moisture. MBP concentrations showed a significant positive correlation with APA (r=0.668, p<0.0001), total organic carbon (r=0.501, p<0.0001), total hydrogen (r=0.483, p<0.0001) and total sulfur (r=0.398, p<0.001), indicating that the production of MBP is associated with microbially mediated factors rather than the contents of TP, IP and OP in the P-enriched ornithogenic soils/sediments. Our results indicated that MBP is an important gaseous link in the phosphorus biogeochemical cycles of ornithogenic tundra ecosystems in Antarctica and Arctic. PMID:21762959

  11. Joint Recovery of f-Elements Using Solvent Based on Carbamoyl-phosphine Oxides Heading Toward ORGA-Process

    SciTech Connect

    Ozawa, M.; Babain, V.; Shadrin, A.; Strelkov, S.; Kiseleva, R.; Murzin, A.

    2007-07-01

    Development of the recovery system which allows realizing joint recovery of all the actinides from the HLW is one of the relevant questions in radiochemistry. Carbamoyl-phosphine oxides (CMPO) were proposed and studied as extractant for rare-earth and transplutonium elements (RE and TPE) recovery from HLW with high acidity, for example TRUEX- and SETFICS-process. Organic system CMPO with TBP in kerosene is usually used as a solvent. However, low solubility of actinide adducts with CMPO results in third phase formation when the actinides concentration in organic phase is high. Application of fluorinated polar diluents increases the solubility of CMPO adducts with actinides in organic phase. It was shown that solvent based on carbamoyl-phosphonate in fluorinated polar diluents allows to recover both uranium and minor actinides concurrently, and there was no precipitation or third phase formation even at high uranium concentration in organic phase. The f-elements joint recovery process based on this solvent was proposed. Solvent containing octyl-phenyl-N,N-di-isobutyl-carbamoyl-methylene-phosphine oxide (O{phi}D[iB]CMPO) in polar diluent meta-nitro-benzo-trifluoride (fluoro-pole-732) was screened out for these studies. And, combined use of them with TBP modifier allows to provide uranium and europium (americium) high recovery characteristics concurrently with an opportunity of attainment of f-elements high concentration in organic phase. As it was indicated, precipitates or third phase was absent even when uranium content in organic phase was 100 g/l. Recovery efficiency to europium remained sufficiently high for its effective recovery. Organic phase saturation about 100% from theoretical attains in europium recovery with this system. Increasing of (O{phi}D[iB]CMPO) concentration in recovery system from 0.2 to 0.8 M results in europium content increasing in organic phase, but no third phase formation is observed. The highest possible europium content in organic phase is about 30 g/l for system with 0.2 M O{phi}D[iB]CMPO and 60- 65 g/l for system with 0.8 M O{phi}D[iB]CMPO. Proposed mixture solvent can be used in joint recovery of all f-elements directly from the dissolver solution of nuclear spent fuel - ORGA-process (abbreviation of Organo-phosphoryl-fluoro-pole solvent for Recovery of Group of Actinides). The ORGA flowsheet is expected to be highly proliferation-resistant, because TRU group and U will separately be recovered by proposed aqueous, salt-free complexants. (authors)

  12. 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

  13. Dissociation and reduction of covalent ?-lactoglobulin-quinone adducts by dithiothreitol, tris(2-carboxyethyl)phosphine, or sodium sulfite.

    PubMed

    Jongberg, Sisse; Lund, Marianne N; Otte, Jeanette

    2015-06-01

    Covalent protein-phenol adducts, generated by reaction of protein nucleophiles with quinones, have recently attracted increased attention because the interactions change the functionality and physicochemical properties of proteins in biological and food systems. The formation of such covalent adducts between ?-lactoglobulin (?-LG) and the quinone of 4-methylcatechol, 4-methylbenzoquinone (4MBQ), and subsequent reduction by dithiothreitol (DTT), tris(2-carboxyethyl)phosphine (TCEP), or sodium sulfite was investigated by mass spectrometry. The results showed that 19.0 8.8% of ?-LG reacted with 4MBQ when present in equimolar ratio at 20C (pH 8.0) to yield the protein-phenol adduct (?-LG-Q). Following treatment with sulfite, DTT, or TCEP, 75, 68, or 36%, respectively, of the formed ?-LG-Q adduct dissociated. Different reaction mechanisms were proposed for the reduction of ?-LG and ?-LG-Q by each of the reducing agents. These results show that on reductive sample preparation for analysis of protein samples, not only are protein polymers formed through oxidative disulfide bonds reduced into the individual protein constituents but also a large part of any protein-phenol adducts present will dissociate and, thus, give a false picture of the level of protein-protein interactions that have occurred in the sample. PMID:25700864

  14. 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

  15. Synergistic Effects of Oxygen on Phosphine and Ethyl Formate for the Control of Phthorimaea operculella (Lepidoptera: Gelechiidae).

    PubMed

    Kim, Hyun Kyung; Lee, Seon-Woo; Kim, Ju-Il; Yang, Jeong-Oh; Koo, Hyun-Na; Kim, Gil-Hah

    2015-12-01

    Phosphine (PH3) and ethyl formate (EF) are two potentially powerful postharvest fumigant insecticides. We investigated the effectiveness of both PH3 and EF as fumigants at all developmental stages of the potato tuber moth Phthorimaea operculella Zeller, and we also studied the synergistic effects of these fumigants under controlled atmospheres of 50 and 80% oxygen (O2). The larval stage of P. operculella was the most susceptible to fumigation with PH3 at both 5C and 20C. All of the developmental stages showed greater susceptibility to PH3 at 20C than at 5C, whereas the susceptibility of adult P. operculella to this fumigant was not affected by temperature. The toxicity of EF did not differ with temperature for any of the P. operculella developmental stages. The atmospheric oxidation of PH3 increased the toxicity of this fumigant toward all developmental stages at both temperatures. In contrast, no differences in toxicity were observed for oxidized EF compared with EF alone at any developmental stage. In conclusion, using fumigation tests, we showed that atmospherically oxidized PH3 was much more effective against P. operculella than PH3 alone, demonstrating a synergistic effect for this fumigant and O2. Therefore, treatment with PH3 and high concentrations of O2, as described in this study, could be useful for managing the postharvest pest P. operculella. PMID:26470389

  16. 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.

  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. 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

  19. 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

  20. 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.

  1. 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.

  2. 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

  3. 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[3,5bis(2pyridyl)1,2,4triazolato]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 (?max ~ 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.

  4. Selective extraction of U(VI) and some other metals from nitric acid media by poly-phosphine poly-oxides

    SciTech Connect

    Nogami, M.; Sugiyama, Y.; Ikeda, Y.; Maruyama, K.

    2008-07-01

    For the selective extraction of radionuclides from nitrate media, the extractabilities of organo-poly-phosphine poly-oxides were examined in the form of impregnated resins. It was found that the extractability of 1,1,3,5,5-pentaphenyl-1,3,5-tri-phospha-pentane trioxide (PPTPT) for U(VI) is quite unusual with very high values at both low and high concentrations of nitric acid, which is not observed for other types of extractants. Thus, this extractant might be promising for the selective extraction of U(VI) in very high concentrations of HNO{sub 3}. (authors)

  5. 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

  6. Structure and Reactivity of [(LPd)n(1,5-cyclooctadiene)] (n=12) Complexes Bearing Biaryl Phosphine Ligands

    PubMed Central

    Lee, Hong Geun; Milner, Phillip J.; Colvin, Michael T.; Andreas, Loren; Buchwald, Stephen L.

    2014-01-01

    The structure of the stable Pd(0) precatalyst [(1,5-cyclooctadiene)(LPd)2] (L = AdBrettPhos) for the Pd-catalyzed fluorination of aryl triflates has been further studied by solid state NMR and X-ray cystrallography of the analogous N-phenylmaleimide complex. The reactivity of this complex with CDCl3 to form a dearomatized complex is also presented. In addition, studies suggest that related bulky biaryl phosphine ligands form similar complexes, although the smaller ligand BrettPhos forms a monomeric [(1,5-cyclooctadiene)(LPd)] species instead. PMID:25346547

  7. 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

  8. 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 inhibitorenzyme 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 hPheP?[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 ?? stacking interaction between a pyridine ring and Tyr372. PMID:25192493

  9. 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

  10. Multifrequency time-resolved electron paramagnetic resonance investigations after photolysis of phosphine oxide photoinitiators. Dependence of triplet mechanism chemically induced dynamic electron polarization on microwave frequency.

    PubMed

    Makarov, Timofei N; Savitsky, Anton N; Mbius, Klaus; Beckert, Dieter; Paul, Henning

    2005-03-17

    Phosphinoyl radicals were produced in benzene solution by photolysis of three acylphosphine oxide photoinitiators, diphenyl-2,4,6-trimethylbenzoyl phosphine oxide (I), bis(2,6-dimethoxybenzoyl)-(2,4,4-trimethylpentyl) phosphine oxide (II), and bis(2,4,6-trimethylbenzoyl) phenylphospine oxide (III). The chemically induced dynamic electron polarization (CIDEP) of the radicals was measured by time-resolved electron paramagnetic resonance spectroscopy at different microwave frequencies/magnetic fields, in S- (2.8 GHz, 0.1 T), X- (9.7 GHz, 0.34 T), Q- (34.8 GHz, 1.2 T), and W-bands (95 GHz, 3.4 T). The CIDEP was found to be due to a triplet mechanism (TM) superimposed by a radical pair mechanism comprising ST(0) as well as ST(-) mixing. Contributions of the different CIDEP mechanisms were separated, and the dependence of the TM polarization on microwave frequency was determined. It agrees well with the numerical solution of the relevant stochastic Liouville equation, which proves the TM theory quantitatively. The applicability of previous approximate analytical formulas for the TM polarization is discussed. Parameters of the excited triplet state of III were estimated from the dependence of the TM polarization on microwave frequency. They are zero-field splitting constant 0.169 cm(-1)

  11. Structure, magnetism and colour in simple bis(phosphine)nickel(II) dihalide complexes: an experimental and theoretical investigation.

    PubMed

    Schultz, Madeleine; Plessow, Philipp-Nikolaus; Rominger, Frank; Weigel, Laura

    2013-12-15

    The complex [1,2-bis(di-tert-butylphosphanyl)ethane-?(2)P,P']diiodidonickel(II), [NiI2(C18H40P2] or (dtbpe-?(2)P)NiI2, [dtbpe is 1,2-bis(di-tert-butylphosphanyl)ethane], is bright blue-green in the solid state and in solution, but, contrary to the structure predicted for a blue or green nickel(II) bis(phosphine) complex, it is found to be close to square planar in the solid state. The solution structure is deduced to be similar, because the optical spectra measured in solution and in the solid state contain similar absorptions. In solution at room temperature, no (31)P{(1)H} NMR resonance is observed, but the very small solid-state magnetic moment at temperatures down to 4?K indicates that the weak paramagnetism of this nickel(II) complex can be ascribed to temperature independent paramagnetism, and that the complex has no unpaired electrons. The red [1,2-bis(di-tert-butylphosphanyl)ethane-?(2)P,P']dichloridonickel(II), [NiCl2(C18H40P2] or (dtbpe-?(2)P)NiCl2, is very close to square planar and very weakly paramagnetic in the solid state and in solution, while the maroon [1,2-bis(di-tert-butylphosphanyl)ethane-?(2)P,P']dibromidonickel(II), [NiBr2(C18H40P2] or (dtbpe-?(2)P)NiBr2, is isostructural with the diiodide in the solid state, and displays paramagnetism intermediate between that of the dichloride and the diiodide in the solid state and in solution. Density functional calculations demonstrate that distortion from an ideal square plane for these complexes occurs on a flat potential energy surface. The calculations reproduce the observed structures and colours, and explain the trends observed for these and similar complexes. Although theoretical investigation identified magnetic-dipole-allowed excitations that are characteristic for temperature-independent paramagnetism (TIP), theory predicts the molecules to be diamagnetic. PMID:24311488

  12. 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

  13. 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.

  14. Monochloro non-bridged half-metallocene-type zirconium complexes containing phosphine oxide-(thio)phenolate chelating ligands as efficient ethylene polymerization catalysts.

    PubMed

    Tang, Xiao-Yan; Wang, Yong-Xia; Liu, San-Rong; Liu, Jing-Yu; Li, Yue-Sheng

    2013-01-14

    A series of novel monochloro half-zirconocene complexes containing phosphine oxide-(thio)phenolate chelating ligands of the type, ClCp'Zr[X-2-R(1)-4-R(2)-6-(Ph(2)P=O)C(6)H(2)](2) (Cp' = C(5)H(5), 2a: X = O, R(1) = Ph, R(2) = H; 2b: X = O, R(1) = F, R(2) = H; 2c: X = O, R(1) = (t)Bu, R(2) = H; 2d: X = O, R(1) = R(2) = (t)Bu; 2e: X = O, R(1) = SiMe(3), R(2) = H; 2f: X = S, R(1) = SiMe(3), R(2) = H; Cp' = C(5)Me(5), 2g: X = O, R(1) = SiMe(3), R(2) = H), have been synthesized in high yields. These complexes were identified by (1)H {(13)C} NMR and elemental analyses. Structures for 2b, 2c and 2f were further confirmed by X-ray crystallography. Structural characterization of these complexes reveals crowded environments around the zirconium. Complexes 2b and 2c adopt six-coordinate, distorted octahedral geometry around the zirconium center, in which the equatorial positions are occupied by three oxygen atoms of two chelating phosphine oxide-bridged phenolate ligands and a chlorine atom. The cyclopentadienyl ring and one oxygen atom of the ligand are coordinated on the axial position. Complex 2f also folds a six-coordinate, distorted octahedral geometry around the Zr center, consisting of a Cp-Zr-O (in P=O) axis [177.16] and a distorted plane of two sulfur atoms and one oxygen atom of two chelating phosphine oxide-bridged thiophenolate ligands as well as a chlorine atom. When activated by modified methylaluminoxane (MMAO), all the complexes exhibited high activities towards ethylene polymerization at high temperature (75 C), giving high molecular weight polymers with unimodal molecular weight distribution. The formation of 14-electron, cationic metal alkyl species might come from the Zr-O (in phenol ring) bond cleavage based on the DFT calculations study. PMID:23073181

  15. Impact of Coordination Geometry, Bite Angle, and Trans Influence on Metal-Ligand Covalency in Phenyl-Substituted Phosphine Complexes of Ni and Pd.

    PubMed

    Donahue, Courtney M; McCollom, Samuel P; Forrest, Chelsie M; Blake, Anastasia V; Bellott, Brian J; Keith, Jason M; Daly, Scott R

    2015-06-15

    Despite the long-standing use of phosphine and diphosphine ligands in coordination chemistry and catalysis, questions remain as to their effects on metal-ligand bonding in transition metal complexes. Here we report ligand K-edge XAS, DFT, and TDDFT studies aimed at quantifying the impact of coordination geometry, diphosphine bite angle, and phosphine trans influence on covalency in M-P and M-Cl bonds. A series of four-coordinate NiCl2 and PdCl2 complexes containing PPh3 or Ph2P(CH2)nPPh2, where n = 1 (dppm), 2 (dppe), 3 (dppp), and 4 (dppb), was analyzed. The XAS data revealed that changing the coordination geometry from tetrahedral in Ni(PPh3)2Cl2 (1) to square planar in Ni(dppe)Cl2 (2) more than doubles the intensity of pre-edge features assigned to Ni-P and Ni-Cl 1s ? ?* transitions. By way of comparison, varying the diphosphine in Pd(dppm)Cl2 (4), Pd(dppp)Cl2 (6), and Pd(dppb)Cl2 (7) yielded Pd-P 1s ? ?* transitions with identical intensities, but a 10% increase was observed in the P K-edge XAS spectrum of Pd(dppe)Cl2 (5). A similar observation was made when comparing Ni(dppe)Cl2 (2) to Ni(dppp)Cl2 (3), and DFT and TDDFT calculations corroborated XAS results obtained for both series. Comparison of the spectroscopic and theoretical results to the diphosphine structures revealed that changes in M-P covalency were not correlated to changes in bite angles or coordination geometry. As a final measure, P and Cl K-edge XAS data were collected on trans-Pd(PPh3)2Cl2 (8) for comparison to the cis diphosphine complex Pd(dppe)Cl2 (5). Consistent with phosphine's stronger trans influence compared to chloride, a 35% decrease in the intensity of the Pd-P 1s ? ?* pre-edge feature and a complementary 34% increase in Pd-Cl 1s ? ?* feature was observed for 8 (trans) compared to 5 (cis). Overall, the results reveal how coordination geometry, ligand arrangement, and diphosphine structure affect covalent metal-phosphorus and metal-chloride bonding in these late transition metal complexes. PMID:25996554

  16. 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

  17. Third phase formation in the extraction of Nd(III) by octyl(phenyl)-N,N-diisobutyl carbamoyl methyl phosphine oxide (O{Phi}CMPO)

    SciTech Connect

    Suresh, A.; Brahmmananda Rao, C.V.S.; Sabharwal, K.N.; Srinivasan, T.G.; Vasudeva Rao, P.R.

    1999-01-01

    Third phase formation in the extraction of Nd(III) by 0.2 M Octyl(Phenyl)-N,N-Diisobutyl Carbamoyl methyl phosphine oxide (O{Phi}CMPO) in n-dodecane has been studied with tri-n-butyl phosphate (TBP) and tri-n-amyl phosphate (TAP) as modifiers to provide a comparison between these two modifier systems. The effect of concentration of TAP as modifier for the extraction of Nd(III) by 0.2 M O{Phi}CMPO has been studied. The extraction of Nd(III) by TAP/n-dodecane in the absence of O{Phi}CMPO has also been studied and the results are reported here.

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

    PubMed

    Kalek, Marcin; Fu, Gregory C

    2015-07-29

    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

  19. 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

  20. Phosphine-Catalyzed Addition/Cycloaddition Domino Reactions of ?'-Acetoxy Allenoate: Highly Stereoselective Access to 2-Oxabicyclo[3.3.1]nonane and Cyclopenta[a]pyrrolizine.

    PubMed

    Gu, Yiting; Hu, Pengfei; Ni, Chunjie; Tong, Xiaofeng

    2015-05-20

    Two classes of phosphine-catalyzed addition/cycloaddition domino reactions of ?'-acetoxy allenoate 1 have been developed. The reaction of 1 with 2-acyl-3-methyl-acrylonitrile 2 readily occurs to give 2-oxabicyclo[3.3.1]nonane 3, furnishing the ?'-addition/[4 + 4] cycloaddition domino sequence. In this sequence, ?'C of allenoate 1 is an electrophilic center, and its ?'C and ?C serve as a 1,4-dipole. When the other reaction partner is switched to 2-acyl-3-(2-pyrrole)-acrylonitrile 8, a ?-addition/[3 + 2] cycloaddition domino reaction is instead observed, in which allenoate 1 exhibits dual electrophilic reactivity of ?C and 1,3-dipole chemical behavior of ?C and ?'C. Furthermore, both of these two asymmetric variants have also been achieved with up to 93% ee. The domino reactions presented in this report are valuable for highly stereoselective construction of complex structures under mild reaction conditions. PMID:25905736

  1. Rhodium(III)-Catalyzed C-H Activation and Annulation with 1-Alkynylphosphine Sulfides: A Mild and Regioselective Access for the Synthesis of Bulky Phosphine Ligands.

    PubMed

    Li, Bin; Yang, Jie; Xu, Hong; Song, Haibin; Wang, Baiquan

    2015-12-18

    We reported herein rhodium(III)-catalyzed C-H activation and annulation reactions for the synthesis of bulky phosphine ligands by using 1-alkynylphosphine sulfides as key starting materials. In the presence of [Cp*RhCl2]2 (5 mol %) and CsOAc (2.0 equiv), various N-(pivaloyloxy)benzamides (3.0 equiv) could react smoothly with 1-alkynylphosphine sulfides at 40 C in MeOH/CF3CH2OH cosolvent without external oxidant. Using [Cp(Ph)RhCl2]2 as catalyst, the reaction can be performed under less loading of benzamides (2.0 equiv) and milder reaction conditions (25 C) with higher regioselectivity. In a sequential cyclization/desulfidation process, this new method provides a variety of bulky heteroarylphosphines with an isoquinolin-1(2H)-one motif. PMID:26595425

  2. 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.

  3. 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.

  4. 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

  5. Insertion of phosphinidene complexes into the P-H bond of secondary phosphine oxides: a new version of the phospha-Wittig synthesis of P[double bond, length as m-dash]C double bonds.

    PubMed

    Hao, Yanwei; Wu, Di; Tian, Rongqiang; Duan, Zheng; Mathey, Franois

    2016-01-01

    Terminal phosphinidene complexes [RP-W(CO)5], as generated at 60 C in the presence of copper chloride from the appropriate 7-phosphanorbornadiene complexes, react with secondary phosphine oxides Ar2P(O)H to give the insertion products into the P-H bonds. After metalation with NaH, these products react with aldehydes to give the corresponding phosphaalkenes which are trapped by dimethylbutadiene. PMID:26661055

  6. Metallo-selective substitution reactions by amines or phosphines in HRuCo/sub 3/(CO)/sub 12/. IR and /sup 1/H and /sup 59/ NMR studies of HRuCo/sub 3/(CO)/sub 12-x/L/sub x/ (L = amines or phosphines; x = 0-2) and crystal structure of HRuCo/sub 3/ (CO)/sub 11/(PPh/sub 3/)

    SciTech Connect

    Matsuzaka, H.; Kodama, T.; Uchida, Y.; Hidai, M.

    1988-07-01

    Reaction of a mixed-metal cluster HRuCo/sub 3/(CO)/sub 12/ with trimethylamine N-oxide or a series of amines leads to the formation of the amine-substituted clusters of the form HRuCo/sub 3/(CO)/sub 11/L (L = NMe/sub 3/, NEt/sub 3/, NMe/sub 2/Ph, rho-H/sub 2/N(C/sub 6/H/sub 4/)NH/sub 2/, 1,4-cyclohexanediamine (1,4-chxn)) in 20-40% yield. The reaction with N,N,N',N'-tetramethylethylenediamine (TMEDA) gives a disubstituted cluster, HRuCo/sub 3/(CO)/sub 10/(TMEDA). IR and /sup 1/H and /sup 59/Co NMR spectra of these clusters indicate that the substitution of amines for the CO ligand takes place preferentially at the ruthenium atom. On the other hand, the reaction with tertiary phosphines gives the phosphine-substituted clusters HRuCo/sub 3/(CO)/sub 12-x/L/sub x/ (L = PPh/sub 3/, x = 1, 2; L = (diphenylphosphino)ethane (dppe), x = 1) in 70-90% yield, where the substitution of phosphines occurs exclusively at the cobalt atom. The structure of HRuCo/sub 3/(CO)/sub 11/(PPh/sub 3/) has been determined by X-ray diffraction. It crystallizes in the space group P2/sub 1//c with a = 11.940 (4) A, b = 17.103 (6) A, c = 17.431 (7) A, ..beta.. = 118.55 (3)/sup 0/, and Z = 4. The cluster has a tetrahedral structure similar to that of the parent HRuCo/sub 3/(CO)/sub 12/ cluster, and the phosphine ligand is axially bonded to one of the three basal cobalt atoms.

  7. Mn2+ complexes of 1-oxa-4,7-diazacyclononane based ligands with acetic, phosphonic and phosphinic acid pendant arms: stability and relaxation studies.

    PubMed

    Draho, Bohuslav; Pniok, Miroslav; Havl?kov, Jana; Kotek, Jan; Csa?ov, Ivana; Hermann, Petr; Luke, Ivan; Tth, Eva

    2011-10-21

    A new class of macrocyclic ligands based on 1-oxa-4,7-diazacyclononane was synthesized and their Mn(2+) complexes were investigated with respect to stability and relaxation properties. Each ligand has two pendant arms involving carboxylic (H(2)L(1)--1-oxa-4,7-diazacyclononane-4,7-diacetic acid), phosphonic (H(4)L(2)--1-oxa-4,7-diazacyclononane-4,7-bis(methylenephosphonic acid)), phosphinic (H(2)L(3)--1-oxa-4,7-diazacyclononane-4,7-bis(methylenephosphinic acid)) or phenylphosphinic (H(2)L(4)--1-oxa-4,7-diazacyclononane-4,7-bis[methylene(phenyl)phosphinic acid]) acid moieties. H(2)L(3) and H(2)L(4) were synthesized for the first time. The crystal structure of the Mn(2+) complex with H(2)L(4) confirmed a coordination number of 6 for Mn(2+). The protonation constants of all ligands and the stability constants of their complexes with Mn(2+) and some biologically or biomedically relevant metal ions were determined by potentiometry. The protonation sequence of H(2)L(3) was followed by (1)H and (31)P NMR titration and the second protonation step was attributed to the second macrocyclic nitrogen atom. The potentiometric data revealed a relatively low thermodynamic stability of the Mn(2+) complexes with all ligands investigated. For H(2)L(3) and H(2)L(4), full Mn(2+) complexation cannot be achieved even with 100% ligand excess. The transmetallation of MnL(1) and MnL(2) with Zn(2+) was too fast to be followed at pH 6. Variable temperature (1)H NMRD and (17)O NMR measurements have been performed on MnL(1) and MnL(2) to provide information on water exchange and rotational dynamics. The (17)O chemical shifts indicate hydration equilibrium between mono- and bishydrated species for MnL(1), while MnL(2) is monohydrated. The water exchange is considerably faster on MnL(1) (k(ex)(298) = 1.2 10(9) s(-1)) than on MnL(2) (k(ex)(298) = 1.2 10(7) s(-1)). Small endogenous anions (phosphate, carbonate, citrate) do not replace the coordinated water in either of the complexes, but they induce their slow decomposition. All Mn(2+) complexes are stable toward air-oxidation. PMID:21887440

  8. 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, Tom; Kub?ek, Vojt?ch; Gutten, Ondrej; Lubal, P?emysl; Kotek, Jan; Pietzsch, Hans-Jrgen; Rulek, Lubomr; 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 ?mol 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

  9. Aluminum dialkyl phosphinate flame retardants and their hydrolysates: analytical method and occurrence in soil and sediment samples from a manufacturing site.

    PubMed

    Niu, Yumin; Liu, Jingfu; Liang, Yong; Hao, Zhineng; Liu, Jiyan; Liu, Yuchen; Sun, Xue

    2014-03-18

    Aluminum dialkyl phosphinates (ADPs) are emerging phosphorus flame retardants due to their superior characteristics, but their analytical method, and occurrence and fate in environments have never been reported. For the first time, we developed a method for the analysis of trace ADPs and their hydrolysates (dialkyl phosphinic acids, DPAs), and studied their occurrences and fates in soils and sediments. We found that ADPs are hardly dissolved in water and organic solvents, but are dissolved and hydrolyzed to DPAs in 30 mM NH3H2O, thus both ADPs and DPAs can be determined by liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) in the form of DPAs. ADPs and DPAs in soil and sediment samples were determined by (i) extracting both ADPs and DPAs with 75 mM NH3 H2O, and selectively extract DPAs only with formic acid-water-methanol (5:5:90, v/v/v); (ii) quantifying the total content of ADPs and DPAs, and DPAs by LC-MS/MS analysis of the DPA contents in the former and the latter extract, respectively; and (iii) calculating ADPs from the content difference between the former and the latter extracts. The limit of quantifications (LOQs) of the proposed method were 0.9-1.0 ?g/kg, and the mean recoveries ranged from 69.0% to 112.4% with relative standard deviations ? 21% (n = 6). In soil and sediment samples around a manufacturing plant, ADPs and DPAs were detected in surface soils in the ranges of 3.9-1279.3 and 1.0-448.6 ?g/kg, respectively. While ADPs were found in all the samples of the soil and sediment cores from the drain outlet and the waste residue treatment site at levels ranging from 30.8 to 4628.0 ?g/kg, DPAs were found in more than 90% of these samples with concentrations in the range of 1.1-374.6 ?g/kg. The occurrences of ADPs and DPAs are not in correlation with the total organic carbon, whereas the occurrences of DPAs are highly correlated with the sample pH. Our study also suggests that the DPAs in the samples sourced from the hydrolysis of ADPs. The high hydrolysis degrees of ADPs (up to 49.6%) suggest that once released into the environment, ADPs are likely to coexist with their hydrolysates. Thus, to evaluate the environmental safety of ADPs, the environmental behavior and toxicity of both ADPs and DPAs should be considered. PMID:24559098

  10. 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

  11. Comparison of the electrochemical and luminescence properties of two carbazole-based phosphine oxide Eu(III) complexes: effect of different bipolar ligand structures.

    PubMed

    Xu, Hui; Yin, Kun; Huang, Wei

    2008-08-25

    The photoluminescence (PL), electrochemical, and electroluminescence (EL) properties of Eu(III) complexes, [Eu(cppo)(2)(tta)(3)] (1) and [Eu(cpo)(2)(tta)(3)] (2; TTA = 2-thenoyltrifluoroacetonate) with two carbazole-based phosphine oxide ligands, 9-[4-(diphenylphosphinoyl)phenyl]-9H-carbazole (CPPO) and 9-(diphenylphosphoryl)-9H-carbazole (CPO), which have different bipolar structures, donor-pi-spacer-acceptor (D-pi-A) or donor-acceptor (D-A) systems respectively, are investigated. The CPPO with D-pi-A architecture has improved PL properties, such as higher PL efficiency and more efficient intramolecular energy transfer, than CPO with the D-A architecture. Gaussian simulation proved the bipolar structures and the double-carrier injection ability of the ligands. The carrier injection abilities of triphenylphosphine oxide, CPO, and CPPO are gradually improved. Notably, the Gaussian and electrochemical investigations indicate that before and after coordination, the carrier injection ability of the ligands show remarkable changes because of the particularity of the D-pi-A and D-A systems. The electrochemical studies demonstrate that coordination induces the electron cloud to migrate from electron-rich carbazole to electron-poor diphenylphosphine oxide, and consequently increases the electron-cloud density on diphenylphosphine oxide, which weakens its ability for electron affinity and induces the elevation of LUMO energy levels of the complexes. Significantly, the pi-spacer in the D-pi-A system exhibits a distinct buffer effect on the variation of the electron-cloud density distribution of the ligand, which is absent in the D-A system. It is demonstrated that the adaptability of the D-pi-A systems, especially for coordination, is stronger than that of D-A systems, which facilitates the modification of the complexes by designing multifunctional ligands purposefully. 1 seems favorable as the most efficient electroluminescent Eu(III) complex with greater brightness, higher efficiencies, and more stable EL spectra than 2. These investigations demonstrate that the phosphine oxide ligands with D-pi-A architecture are more appropriate than those with D-A architecture to achieve multifunctional electroluminescent Eu(III) complexes. PMID:18563765

  12. Production of Galactooligosaccharides Using ?-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

    ?-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% (wv?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

  13. 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

  14. 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.

  15. 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

  16. 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.

  17. Effect of substituents at the nitrogen atom in diaryl [dialkyl(diaryl)carbamoylmethyl]phosphine oxides on their extraction ability and solubility

    SciTech Connect

    Chmutova, M.K.; Litvina, M.N.; Pribylova, G.A.

    1995-09-01

    Extraction of nitric acid and americium(III) with dichloroethane solutions of [diphenyldialkyl(diaryl)carbamoylmethyl]phosphine oxides containing various substituents at the nitrogen atom has been studied. Complexes with one, two, or three acid molecules per reagent molecule are extracted from nitric acid solutions. The extraction constants of nitric acid (K{sub ex}{sup HNO3}) with all reagents have been calculated. The K{sub ex}{sup HNO3} is linearly dependent on the reagent basicity (pK{sub a}). Americium (III) is extracted by octyl-substituted reagents as di- and trisolvates and by other reagents as disolvates. With increasing pK{sub a}, the extraction constants of americium (K{sub ex}{sub Am}) increase, irrespective of the nature of substituent at the nitrogen atom. In extraction of americium (III) with reagents aryl-substituted at the nitrogen atom, no anomalous aryl strengthening (AAS) is observed. The effect of alkyl substituents at phosphorus and nitrogen atoms on the extraction ability of the reagents is almost identical. The difference in this effect is revealed only in the systems with aryl-substituted reagents owing to effect of AAS.

  18. Reversible formation of [P{sub 2}PtH]{sub 2} platinum(I) complexes from cis-P{sub 2}PtH{sub 2} complexes, where P{sub 2} is a chelating phosphine

    SciTech Connect

    Schwartz, D.J.; Andersen, R.A. |

    1995-04-12

    Several platinum cis-dihydride phosphine complexes, (diphos)PtH{sub 2} [4, diphos = iPr{sub 2}P(CH{sub 2}){sub 2}PiPr{sub 2} (dippe); 5, diphos = Cy{sub 2}P(CH{sub 2}){sub 2}PCy{sub 2} (dcype); and 6, diphos = tBu{sub 2}P(CH{sub 2}){sub 2}PtBu{sub 2} (dtbpe)], have been found to be unstable in solution, reversibly losing H{sub 2} and forming binuclear complexes of the general formula [(P-P)Pth]{sub 2}. The extent of dimerization in solution is directly related to the steric size of the phosphine ligand, larger phosphines imparting kinetic stability to the cis-dihydride monomers. The dimeric complexes possess terminal hydride ligands on the basis of their IR spectra; however, the room-temperature {sup 1}H, {sup 31}P({sup 1}H), and {sup 195}Pt({sup 1}H) NMR spectra show equivalence within the sets of H, Pt, and P nuclei, indicating that the dimers are fluxional in solution. This fluxional process can be stopped at low temperature for the (dippe) and (dcype) derivatives, 1 and 2, but not for the (dtbpe) derivative, 3. The complex 1 crystallizes in the orthorhombic space group P2{sub 1}2{sub 1}2{sub 1} in a cell of dimensions a = 9.245(2) A, b = 16.966(2) A, c = 22.690(6) A, and Z = 4. 22 refs., 10 figs., 8 tabs.

  19. Solution-processible brilliantly luminescent Eu(III) complexes with host-featured phosphine oxide ligands for monochromic red-light-emitting diodes.

    PubMed

    Wang, Jianzhe; Han, Chunmiao; Xie, Guohua; Wei, Ying; Xue, Qin; Yan, Pengfei; Xu, Hui

    2014-08-25

    A series of solution-processible electroluminescent (EL) Eu(3+) complexes were constructed with a self-host strategy, in which neutral ligands were employed as functionalized bidentate phosphine oxide (PO) ligands named DPEPOArn (DPEPO = bis(2-(diphenylphosphino)phenyl) ether oxide). The solubility of these complexes was dramatically improved owing to the increased ratios of organic components. This further enhanced the antenna effect of these ligands in both singlet and triplet energy-transfer processes to support high photoluminescent quantum yields (PLQYs) up to 86?% for their Eu(3+) complexes, which is outstanding among conjugated Eu(3+) complexes. Density function theory (DFT) simulations and electrochemical analysis further verified the contributions of DPEPOArn to the carrier injecting/transporting ability of the complexes. In this sense, these functionalized PO ligands served as hosts in optoelectronic processes, which rendered the self-host feature of their Eu(3+) complexes. With the enhanced electrical properties, the spin-coated single-layer organic light-emitting diodes (OLEDs) of these complexes achieved improved low driving voltages, such as onset voltages about 6?V, compared to their Eu(3+)-contained red-emitting polymeric analogues. [Eu(DBM)3DPEPODPNA2] (DBM = 1,3-diphenylpropane-1,3-dione, DPNA = diphenylnaphthylamine) with the most enhanced electrical properties and suitable frontier molecular orbital (FMO) and triplet state locations endowed its devices with the biggest maximum luminance of >90?cd?m(-2) and the highest EL efficiencies. This work verified the potential of small molecular EL Eu(3+) complexes for solution-processed OLEDs through rational function integrations. PMID:25065610

  20. Single-Crystal (31)P NMR and X-ray Diffraction Study of a Molybdenum Phosphine Complex: (5-Methyldibenzophosphole)pentacarbonylmolybdenum(0).

    PubMed

    Eichele, Klaus; Wasylishen, Roderick E.; Maitra, Kalyani; Nelson, John H.; Britten, James F.

    1997-07-30

    The molecular structure of (5-methyldibenzophosphole)pentacarbonylmolybdenum(0), 1, has been determined by X-ray crystallography. The crystal is monoclinic C2/c, Z = 8, with unit cell dimensions of: a = 31.113(2) , b =7.7917(5) , c = 17.9522(12) , and beta = 122.135(4) degrees. Least-squares refinement converged to R(F) = 0.0245 for 2407 independent reflections. The molecular structure is typical of phosphine-substituted metal carbonyls. It contains an approximate mirror plane which bisects the dibenzophosphole framework. Phosphorus-31 NMR spectra of powder and single-crystal samples of 1 have been obtained with cross-polarization and (1)H high-power decoupling. The (31)P CP/MAS NMR spectra exhibit exceptionally well-resolved satellites due to spin-spin coupling interactions with (95,97)Mo (I = (5)/(2)). Using first-order perturbation theory, the multiplets have been analyzed to yield (1)J((95,97)Mo,(31)P) = 123(2) Hz and estimates of the molybdenum nuclear quadrupolar coupling constants, chi((95)Mo) = -0.87 MHz and chi((97)Mo) = 10.1 MHz. Phosphorus-31 NMR spectra of a large single crystal of 1 have been investigated as a function of orientation about three orthogonal axes in the applied magnetic field. Analysis of the data yields the three principal components of the phosphorus chemical shift tensor, delta(11) = 112 ppm, delta(22) = -23 ppm, and delta(33) = -40 ppm; delta(22) lies close to the Mo-P bond (8 degrees ), while delta(11) lies in the approximate mirror plane. The phosphorus chemical shift tensor determined for 1 is compared with the limited anisotropic phosphorus shift data available in the literature. PMID:11670035

  1. Synthesis of gold phosphido complexes derived from bis(secondary) phosphines. structure of tetrameric [Au(MesP(CH(2))(3)PMes)Au](4).

    PubMed

    Lane, Elizabeth M; Chapp, Timothy W; Hughes, Russell P; Glueck, David S; Feland, Brett C; Bernard, Guy M; Wasylishen, Roderick E; Rheingold, Arnold L

    2010-04-19

    Treatment of 2 equiv of Au(THT)Cl (THT = tetrahydrothiophene) with the bis(secondary) phosphines HP(R) approximately PH(R) (linker approximately = (CH(2))(3), R = Mes = 2,4,6-Me(3)C(6)H(2) (1), R = Is = 2,4,6-(i-Pr)(3)C(6)H(2) (2), R = Ph (4); approximately = (CH(2))(2), R = Is (3); HP(R) approximately PH(R) = 1,1'-(eta(5)-C(5)H(4)PHPh)(2)Fe (5)), gave the dinuclear complexes (AuCl)(2)(mu-HP(R) approximately PH(R)) (6-10). Dehydrohalogenation with aqueous ammonia gave the phosphido complexes [(Au)(2)(mu-P(R) approximately P(R))](n) (11-15). Ferrocenyl- and phenylphosphido derivatives 15 and 14 were insoluble; the latter was characterized by solid-state (31)P NMR spectroscopy. Isitylphosphido complexes 12 and 13 gave rise to broad, ill-defined NMR spectra. However, mesitylphosphido complex 11 was formed as a single product, which was characterized by multinuclear solution NMR spectroscopy, solid-state (31)P NMR spectroscopy, and elemental analyses. Mass spectrometry suggested that this material contained eight gold atoms (n = 4). A structure proposed on the basis of the (1)H NMR spectra, containing a distorted cube of phosphorus atoms, was confirmed by X-ray crystallographic structure determination. NMR spectroscopy, including measurement of the hydrodynamic radius of 11 by (1)H NMR DOSY, suggested that this structure was maintained in solution. Density functional theory (DFT) structural calculations on 11 were also in good agreement with the solid-state structure. PMID:20232831

  2. 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

  3. 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.

  4. 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

  5. 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.

  6. Bis(azido) compounds of Pd and Pt with bulky phosphine ligands (dppn=1,8-bis(diphenylphosphino)naphthalene, dppf=1,1?-bis(diphenylphosphino)ferrocene, 1-dpn=1-diphenylphosphino-naphthalene): Preparation, structures, and reactivity toward isocyanides

    NASA Astrophysics Data System (ADS)

    Huh, Hyun Sue; Lee, Yeon Kyoung; Lee, Soon W.

    2006-05-01

    Pd-bis(azido) compounds [Pd(dppn)(N 3) 2] and [Pd(dppf)(N 3) 2], which contain bulky chelating bis(phosphine) ligands (dppn=1,8-bis(diphenylphosphino)naphthalene, dppf=1,1'-bis(diphenylphosphino)ferrocene), were prepared from the corresponding chlorides and NaN 3. We also prepared the Pt-bis(azido) compound [Pt(1-dpn)(SMe 2)(N 3) 2] containing a bulky monodentate phosphine (1-dpn=1-diphenylphosphino-naphthalene). All these compounds underwent [2+3] cycloaddition with isocyanides (R-NC, R=cyclohexyl, tert-butyl, 2,6-dimethylphenyl) to convert azido ligands to five-membered, C-coordinated tetrazolate rings. In addition, we observed the [Pd(dppn)Cl 2]-mediated C-C coupling of PhC tbnd6 CH to generate the ? 2-PhC tbnd6 C-C tbnd6 CPh ligand. All compounds have been structurally characterized by X-ray diffraction.

  7. Density functional analysis of geometries and electronic structures of gold-phosphine clusters. The case of Au4(PR3)42+ and A(u4?2-I)2(PR3)4.

    PubMed

    Ivanov, Sergei A; Arachchige, Indika; Aikens, Christine M

    2011-07-14

    Geometries, ligand binding energies, electronic structure, and excitation spectra are determined for Au(4)(PR(3))(4)(2+) and Au(4)(?(2)-I)(2)(PR(3))(4) clusters (R = PH(3), PMe(3), and PPh(3)). Density functionals including SVWN5, X?, OPBE, LC-?PBE, TPSS, PBE0, CAM-B3LYP, and SAOP are employed with basis sets ranging from LANL2DZ to SDD to TZVP. Metal--metal and metal--ligand bond distances are calculated and compared with experiment. The effect of changing the phosphine ligands is assessed for geometries and excitation spectra. Standard DFT and hybrid ONIOM calculations are employed for geometry optimizations with PPh(3) groups. The electronic structure of the gold--phosphine clusters examined in this work is analyzed in terms of cluster ("superatom") orbitals and d-band orbitals. Transitions out of the d band are significant in the excitation spectra. The use of different basis sets and DFT functionals leads to noticeable variations in the relative intensities of strong transitions, although the overall spectral profile remains qualitatively unchanged. The replacement of PMe(3) with PPh(3) changes the nature of the electronic transitions in the cluster due to low-lying ?*-orbitals. To reproduce the experimental geometries of clusters with PPh(3) ligands, computationally less expensive PH(3) or PMe(3) ligands are sufficient for geometry optimizations. However, to predict cluster excitation spectra, the full PPh(3) ligand must be considered. PMID:21678946

  8. 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

  9. 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

  10. Structural Properties, Cytotoxicity, and Anti-Inflammatory Activity of Silver(I) Complexes with tris(p-tolyl)Phosphine and 5-Chloro-2-Mercaptobenzothiazole

    PubMed Central

    Kyros, L.; Kourkoumelis, N.; Kubicki, M.; Male, L.; Hursthouse, M. B.; Verginadis, I. I.; Gouma, E.; Karkabounas, S.; Charalabopoulos, K.; Hadjikakou, S. K.

    2010-01-01

    The synthesis and characterization of the silver(I) chloride complex of formula {[AgCI(CMBZT)(TPTP)2] (MeOH)} (1) (CMBZT = 5-chloro-2-mercaptobenzothiazole, TPTP = tris(p-tolyl)phosphine) is described. Also the structure of the hydrate derivative {[AgCI(TPTP)3] (0.5 H2O)} (2) of the corresponding known anhydrous silver complex (Zartilas et al., 2009), and the polymorph 3 of the known [AgI(TPTP)3] complex (Zartilas et al., 2009) were determined and compared with the known ones. In addition, the structure of the known one silver(I) cluster {[AgI(TPTP)]4} (4) (Meijboom et al., 2009) was re-determined at 120(2) K and possible Ag-Ag interactions were analyzed. The compounds 14 were characterized by X-ray crystallography at r.t (1) and 120 K (24). All these complexes and {[(Et3NH)+]2 [Ag6(?3-Hmna)4(?3-mna)2]2? (DMSO)2 (H2O)} (5) (Hmna = 2-mercaptonicotinic acid) were evaluated for cytotoxic and anti-inflammatory activity. The in vitro testing of cytotoxic activity of 15 against leiomyosarcoma cancer cells (LMS), were evaluated with Trypan Blue and Thiazolyl Blue Tetrazolium Bromide or 3-(4.5-dimethylthiazol-2-yl)-2.5-diphenyltetrazolium bromide (MTT) assays. The flow cytometry assay for complex 1 and showed that at 15??M of 1, 62.38% of LMS cells undergo apoptosis, while 7% of LMS cells undergo cell necrosis. The antitumor activity of 3 is comparable with that of its reported polymorph (Zartilas et al., 2009). The anti-inflammatory, activity of complexes 13 and 5 was also studied. The activity towards cell viability was 2 > 3 > 5 > 1 > 4, while the order of the inhibitory activity in cell growth proliferation follows the order, 2 > 3 > 1 > 4 > 5. The anti-inflammatory activity on the other hand is 1 > 2 > 5 > ? >3. PMID:20379345

  11. Thermodynamic, kinetic, and mechanistic study of oxygen atom transfer from mesityl nitrile oxide to phosphines and to a terminal metal phosphido complex.

    PubMed

    Cai, Xiaochen; Majumdar, Subhojit; Fortman, George C; Frutos, Luis Manuel; Temprado, Manuel; Clough, Christopher R; Cummins, Christopher C; Germain, Meaghan E; Palluccio, Taryn; Rybak-Akimova, Elena V; Captain, Burjor; Hoff, Carl D

    2011-10-01

    The enthalpies of oxygen atom transfer (OAT) from mesityl nitrile oxide (MesCNO) to Me(3)P, Cy(3)P, Ph(3)P, and the complex (Ar[(t)Bu]N)(3)MoP (Ar = 3,5-C(6)H(3)Me(2)) have been measured by solution calorimetry yielding the following P-O bond dissociation enthalpy estimates in toluene solution (3 kcal mol(-1)): Me(3)PO [138.5], Cy(3)PO [137.6], Ph(3)PO [132.2], (Ar[(t)Bu]N)(3)MoPO [108.9]. The data for (Ar[(t)Bu]N)(3)MoPO yield an estimate of 60.2 kcal mol(-1) for dissociation of PO from (Ar[(t)Bu]N)(3)MoPO. The mechanism of OAT from MesCNO to R(3)P and (Ar[(t)Bu]N)(3)MoP has been investigated by UV-vis and FTIR kinetic studies as well as computationally. Reactivity of R(3)P and (Ar[(t)Bu]N)(3)MoP with MesCNO is proposed to occur by nucleophilic attack by the lone pair of electrons on the phosphine or phosphide to the electrophilic C atom of MesCNO forming an adduct rather than direct attack at the terminal O. This mechanism is supported by computational studies. In addition, reaction of the N-heterocyclic carbene SIPr (SIPr = 1,3-bis(diisopropyl)phenylimidazolin-2-ylidene) with MesCNO results in formation of a stable adduct in which the lone pair of the carbene attacks the C atom of MesCNO. The crystal structure of the blue SIPrMesCNO adduct is reported, and resembles one of the computed structures for attack of the lone pair of electrons of Me(3)P on the C atom of MesCNO. Furthermore, this adduct in which the electrophilic C atom of MesCNO is blocked by coordination to the NHC does not undergo OAT with R(3)P. However, it does undergo rapid OAT with coordinatively unsaturated metal complexes such as (Ar[(t)Bu]N)(3)V since these proceed by attack of the unblocked terminal O site of the SIPrMesCNO adduct rather than at the blocked C site. OAT from MesCNO to pyridine, tetrahydrothiophene, and (Ar[(t)Bu]N)(3)MoN was found not to proceed in spite of thermochemical favorability. PMID:21875050

  12. Why did incorporation of acrylonitrile to a linear polyethylene become possible? Comparison of phosphine-sulfonate ligand with diphosphine and imine-phenolate ligands in the Pd-catalyzed ethylene/acrylonitrile copolymerization.

    PubMed

    Nozaki, Kyoko; Kusumoto, Shuhei; Noda, Shusuke; Kochi, Takuya; Chung, Lung Wa; Morokuma, Keiji

    2010-11-17

    Palladium-catalyzed coordination-insertion copolymerization of ethylene with acrylonitrile (AN) proceeded only by using phosphine-sulfonate (P-SO(3)) as a ligand among the neutral and anionic ligands we examined, those are phosphine-sulfonate (P-SO(3)), diphosphine (P-P), and imine-phenolate (N-O). In order to answer a question that is unique for P-SO(3), theoretical and experimental studies were carried out for the three catalyst systems. By comparing P-SO(3) and P-P, it was elucidated that (i) the ?-acrylonitrile complex [(L-L')PdPr(?-AN)] is less stable than the corresponding ?-complex [(L-L')PdPr(?-AN)] in both the phosphine-sulfonato complex (L-L' = P-SO(3)) and the diphosphine complex (L-L' = P-P) and (ii) the energetic difference between the ?-complex and the ?-complex is smaller in the P-SO(3) complexes than in the P-P complexes. Thus, the energies of the transition states for both AN insertion and its subsequent ethylene insertion relative to the most stable species [(L-L')PdPr(?-AN)] are lower for P-SO(3) than for P-P. The results nicely explain the difference between these two types of ligands. That is, ethylene insertion subsequent to AN insertion was detected for P-SO(3), while aggregate formation was reported for cationic [(L-L)Pd(CHCNCH(2)CH(3))] complex. Aggregate formation with the cationic complex can be considered as a result of the retarded ethylene insertion to [(L-L)Pd(CHCNCH(2)CH(3))]. In contrast, theoretical comparison between P-SO(3) and N-O did not show a significant energetic difference in both AN insertion and its subsequent ethylene insertion, implying that ethylene/AN copolymerization might be possible. However, our experiment using [(N-O)PdMe(lutidine)] complex revealed that ?-hydride elimination terminated the ethylene oligomerization and, more importantly, that the resulting Pd-H species lead to formation of free N-OH and Pd(0) particles. The ?-hydride elimination process was further studied theoretically to clarify the difference between the two anionic ligands, P-SO(3) and N-O. PMID:20973530

  13. Tri-p-tolylphosphine

    PubMed Central

    Wang, Hao; Wang, Yi-Bin; Liu, Bo-Nian; Tang, Shi-Gui; Wei, Ping

    2008-01-01

    In the title compound C21H21P, the P atom is situated on a crystallographic threefold rotatory-inversion axis, resulting in threefold rotation symmetry of the title compound. The dihedral angles between the symmetry-related benzene rings are 87.40?(18). PMID:21201763

  14. 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

  15. 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.

  16. 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.

  17. Cu(I) complexes bearing the new sterically demanding and coordination flexible tris(3-phenyl-1-pyrazolyl)methanesulfonate ligand and the water-soluble phosphine 1,3,5-triaza-7-phosphaadamantane or related ligands.

    PubMed

    Wanke, Riccardo; Smole?ski, Piotr; da Silva, M Ftima C Guedes; Martins, Lusa M D R S; Pombeiro, Armando J L

    2008-11-01

    The new sterically hindered scorpionate tris(3-phenylpyrazolyl)methanesulfonate (Tpms(Ph))(-) has been synthesized and its coordination behavior toward a Cu(I) center, in the presence of 1,3,5-triaza-7-phosphaadamantane (PTA), N-methyl-1,3,5-triaza-7-phosphaadamantane tetraphenylborate ((mPTA)[BPh4]) or hexamethylenetetramine (HMT) has been studied. The reaction between Li(Tpms(Ph)) (1) and [Cu(MeCN)4][PF6] yields [Cu(Tpms(Ph))(MeCN)] (2) which, upon further acetonitrile displacement on reaction with PTA, HMT, or (mPTA)[BPh4], gives the corresponding complexes [Cu(Tpms(Ph))(PTA)] (3), [Cu(Tpms(Ph))(HMT)] (4), and [Cu(Tpms(Ph))(mPTA)][PF6] (5). All the compounds have been characterized by (1)H, (31)P, (13)C, COSY or HMQC-NMR, IR, elemental analysis, and single crystal X-ray diffraction. In the complexes (3) and (5), which bear a phosphine ligand (i.e., PTA and mPTA, respectively), the new scorpionate ligand shows the typical N, N, N-coordination mode, whereas in (2) and (4), bearing a N-donor ligand (i.e., MeCN and HMT, respectively), it binds the metal via the N,N,O chelating mode, involving the sulfonate moiety. PMID:18841929

  18. 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

  19. 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

  20. Bioinspired Hydrogenase Models: The Mixed-Valence Triiron Complex [Fe3(CO)7(?-edt)2] and Phosphine Derivatives [Fe3(CO)7x(PPh3)x(?-edt)2] (x = 1, 2) and [Fe3(CO)5(?2-diphosphine)(?-edt)2] as Proton Reduction Catalysts

    PubMed Central

    2014-01-01

    The mixed-valence triiron complexes [Fe3(CO)7x(PPh3)x(?-edt)2] (x = 02; edt = SCH2CH2S) and [Fe3(CO)5(?2-diphosphine)(?-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 HBF4Et2O, but addition of acid to the pentacarbonyl complexes results in one-electron oxidation to yield the moderately stable cations [Fe3(CO)5(PPh3)2(?-edt)2]+ and [Fe3(CO)5(?2-diphosphine)(?-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(?-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(?-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(?-edt)], [Fe3(CO)7(?-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 ironiron 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

  1. Synthetic, Structural, Spectroscopic, and Theoretical Studies of Structural Isomers of the Cluster Pt(3)(&mgr;-PPh(2))(3)Ph(PPh(3))(2). A Unique Example of Core Isomerism in Phosphine Phosphido-Rich Clusters.

    PubMed

    Bender, Robert; Braunstein, Pierre; Dedieu, Alain; Ellis, Paul D.; Huggins, Beth; Harvey, Pierre D.; Sappa, Enrico; Tiripicchio, Antonio

    1996-02-28

    Two isomers of the phosphido-bridged platinum cluster Pt(3)(&mgr;-PPh(2))(3)Ph(PPh(3))(2) (2 and 3) have been isolated, and their structures have been solved by single-crystal X-ray diffraction. Compound 2 crystallizes in the orthorhombic space group Cmc2(1) with a = 22.192(10) , b = 17.650(9) , c = 18.182(8) , and Z = 4. Compound 3 crystallizes with 2 molecules of dichloromethane in the monoclinic space group C2/c with a = 21.390(10) , b = 18.471(9) , c = 19.021(11) , beta = 105.27(5) degrees, and Z = 4. The two isomers differ essentially in their metal-metal distances and Pt-(&mgr;-PPh(2))-Pt angles. Thus 2, having an imposed C(s) symmetry, contains a bent chain of metal atoms with two short Pt-Pt distances of 2.758(3) and a long separation of 3.586(2) . In 3, which has an imposed C(2) symmetry, the metal atoms form an isosceles triangle with two Pt-Pt distances of 2.956(3) and one of 3.074(4) . These isomers can be smoothly interconverted by changing the crystallization solvents. Solution and solid-state (31)P NMR studies have been performed in order to assign the resonances of the different P nuclei and relate their chemical shifts with their structural environments. Raman spectroscopy was used to assign the nu(Pt-Pt) modes of the two structural isomers. Theoretical studies based on extended Hckel calculations and using the fragment molecular orbital approach show that the isomer with the three medium Pt-Pt distances is slightly more stable, in agreement with earlier theoretical predictions. Cluster core isomerism remains a rare phenomenon, and the present example emphasizes the role and the importance of flexible phosphido bridges in stabilizing clusters as well as the unprecedented features which can be observed in phosphine phosphido-rich metal clusters. PMID:11666312

  2. Cyanidotetra-kis-(trimethyl-phosphine)cobalt(I).

    PubMed

    Xu, Xiaofeng; Feng, Lei; Li, Xiaoyan

    2011-04-01

    The title compound, [Co(CN)(C(3)H(9)P)(4)], was obtained as a product of the reaction of [Co(PMe(3))(4)] with a molar equivalent of 2,6-difluoro-benzonitrile in diethyl ether. This compound is stable in the air for several hours, but rapidly decomposes at room temperature in solution. The cobalt(I) atom has s trigonal-bipyramidal coordination enviroment in which the cyano group and one of the PMe(3) groups are in the axial positions. PMID:21754010

  3. 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...

  4. 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...

  5. 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...

  6. 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...

  7. 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...

  8. Systematization of published data on phosphine isotopologues

    NASA Astrophysics Data System (ADS)

    Akhlestin, A. Y.; Voronina, S. S.; Privezentsev, A. I.; Fazliev, A. Z.

    2012-11-01

    This is a continuation of a series of papers on the systematization of spectroscopic information on a number of atmospheric molecules (H2O [1], H2S [2], NH3 [3], CO2 [4], etc). The purpose of this work is to develop a database and a knowledge base of phospine isotopologues. The data imported from publications are validated. The technical aspect of the systematization implies its representation in the form of ontology (logical theory) that provides an automatic check for the consistency of classes and class attribution of individuals. Individuals in the knowledge base describe the properties of the published spectral line parameters.

  9. Technetium(III) complexes with the tetradentate umbrella ligand tris (o-mercaptophenyl)phosphinate: X-ray structural characterization of Tc(P(o-C sub 6 H sub 4 S) sub 3 )(CNC sub 3 H sub 7 ) and Tc(P(o-C sub 6 H sub 4 S) sub 3 )(CNC sub 3 H sub 7 ) sub 2

    SciTech Connect

    de Vries, N.; Cook, J.; Davison, A. ); Jones, A.G. )

    1991-06-12

    Tris(o-mercaptophenyl) phosphinate (PS3) binds to Tc(III) as a tetradentate ligand to form the formally 14-electron complex Tc(PS3)(CNMe). An x-ray single-crystal structure determination of the isopropyl isocyanide derivative Tc(PS3)(CN-i-Pr) shows sulfurs bound in the equatorial plane. The crystal data for MF = C{sub 22}H{sub 19}NPS{sub 3}Tc is presented. In the presence of a large excess of isonitrile, these electron-deficient complexes bind a sixth ligand. The six-coordinate complex Tc(PS3)(CN-i-Pr){sub 2}, was also structurally characterized and the crystal data is presented. 8 refs., 2 figs., 4 tabs.

  10. Crystal structures and vibrational and solution and solid-state (CPMAS) NMR spectroscopic studies in triphenyl phosphine, arsine, and stibine silver(I) bromate systems, (R3E)xAgBrO3 (E = P, As, Sb; x = 1-4).

    PubMed

    Cingolani, Augusto; Effendy, Effendy; Hanna, John V; Pellei, Maura; Pettinari, Claudio; Santini, Carlo; Skelton, Brian W; White, Allan H

    2003-08-11

    Adducts of triphenyl phosphine, triphenyl arsine, and triphenyl stibine with silver(I) bromate have been synthesized and characterized both in solution ((1)H and ESI MS spectroscopy) and in the solid state (IR, single-crystal X-ray structure analysis). The triphenyl phosphine complexes have been also investigated by (31)P[(1)H] solution and (31)P cross-polarization magic-angle-spinning (CPMAS) NMR spectroscopy. The topology of the structures in the solid state was found to depend on the nature of EPh(3) and on the stoichiometric ratio AgBrO(3)/EPh(3). In AgBrO(3)/PPh(3) (1:1)(4) (1) and AgBrO(3)/PPh(3) (1:2) (2), the bromate is in the unfamiliar and hitherto structurally uncharacterized role of coordinating ligand, the complex having a mononuclear form in 2 and a less familiar tetrameric form in 1. In AgBrO(3)/AsPh(3) (1:4).CH(3)OH (7) and AgBrO(3)/SbPh(3) (1:4).C(2)H(5)OH (11), the cations are the familiar homoleptic [Ag(EPh(3))(4)](+) array with the bromate role simply that of counterion. The AgBrO(3)/AsPh(3) (1:2)(2).0.7"H(2)O" derivative (6) is binuclear L(2)Ag(mu-BrO(3))(2)AgL(2) with a four-membered ring core (L = AsPh(3)). PMID:12895118

  11. 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.

  12. Synthesis and X-ray Structural Study on the Complexes of Silver(I) Halide with Tricyclohexylephosphine, Diphenyl-(2,4,6-trimethoxy)phenylphosphine, Phenyl-2,4,6-trimethoxyphenyl phosphine, and Tris(2,4,6-trimethoxy)phenylphosphine

    SciTech Connect

    Effendy; White, A. H.

    2008-03-17

    A diverse array of structures for the complexes of silver(I) halide with triphenylphosphine (PPh{sub 3}) has been studied. The complexes may be described as being of the type [AgX(PPh{sub 3}){sub n}] (X = Cl, Br or I). The value of n varies in the range of 1-3. This also indicates that the stoichiometry of the complexes is in the range of 1-3. The complex with stoichiometry 1:1 is a tetramer. There are two structural types of tetramer reported, termed cubane and step or chair. The cubane structure has been reported for [AgX(PPh{sub 3})]{sub 4} (X = Cl, Br or I), while the step structure has only been reported for [AgI(PPh{sub 3})]{sub 4}. The complex with stoichiometry 1:2 may be a monomer or a dimer. The monomer has a quasi trigonal planar structural type and has only been reported for [AgBr(PPh{sub 3}){sub 2}]. The dimer has been reported for [(PPh{sub 3}){sub 2}Ag({mu}-X){sub 2}Ag(PPh{sub 3}){sub 2}] (X = Cl or Br) with silver atom in the distorted tetrahedral environment. The complex with stoichiometry 1:3 has a distorted tetrahedral structural type and has been reported for [AgX(PPh{sub 3}){sub 3}] (X = Cl, Br or I). Changing PPh{sub 3} with more hindered ligand such as tricyclohexylephosphine (Pcy{sub 3}) or derivative of PPh{sub 3} such as diphenyl-2,4,6-trimethoxy(phenyl)phosphine (dpmp), phenyl-bis{l_brace}2,4,6-trimethoxy(phenyl){r_brace} phosphine (pdmp), or tris{l_brace}2,4,6-trimethoxy(phenyl){r_brace}phosphine (tmpp) may give complexes with various structural types but with lower range of stoichiometry. Synthesis and X-ray structural study of these complexes has been done with the results summarized below. Silver(I) halide and Pcy{sub 3} give complexes with stoichiometry 1:1 and 1:2. The complex with stoichiometry 1:1 is a dimer or cubane. The dimer is observed for [(Pcy{sub 3})Ag({mu}-X){sub 2}Ag(Pcy{sub 3})] (X = Cl or Br). The unusual dimer is observed for [(Pcy{sub 3})Ag({mu}-I){sub 2}({mu}-py)Ag(Pcy{sub 3})] where the pyridine ligand is bonded to two silver atoms. The cubane is observed for [AgI(Pcy{sub 3})]{sub 4}. The complex with stoichiometry 1:2 has a quasi trigonal planar structural type and has been observed for [AgX(Pcy{sub 3}){sub 2}] (X = Cl, Br, I). Silver(I) halide and dpmp give complexes with stoichiometry 1:1 and 1:2. The complex with stoichiometry 1:1 is a dimer and has been observed for [(dpmp)Ag({mu}-X){sub 2}Ag(dpmp)] (X = Cl, Br or I). The complex with stoichiometry 1:2 has a quasi trigonal planar structural type and has been observed for [AgX(dpmp){sub 2}] (X = Cl, Br, I). Silver(I) halide and pdmp also give complexes with stoichiometry 1:1 and 1:2. The complex with stoichiometry 1:1 is a dimer and has been observed for [(pdmp)Ag({mu}-X){sub 2}Ag(pdmp)] (X Cl, Br or I). The complex with stoichiometry 1:2 has a quasi trigonal planar structural type and has been observed for [AgX(pdmp){sub 2}] (X = Cl, Br, I). Silver(I) halide and tmmp only give complexes with stoichiometry 1:1. This complex is a monomer and has been observed for [AgX(tmpp)] (X = Cl or Br). In this complex the silver atom is in a quasi linear environment. Based on the bond lengths between silver and phosphorous atoms in the complexes obtained, it can be concluded that bulky ligands tend to give complexes with lower range of stoichiometry. In addition, the bulkier the ligand the longer the bond length between the silver and phosphorous atoms.

  13. Phosphine-Free EWG-Activated Ruthenium Olefin Metathesis Catalysts

    NASA Astrophysics Data System (ADS)

    Grela, Karol; Szadkowska, Anna; Michrowska, Anna; Bieniek, Michal; Sashuk, Volodymyr

    Hoveyda-Grubbs catalyst has been successfully fine-tuned by us in order to increase its activity and applicability by the introduction of electron-withdrawing groups (EWGs) to diminish donor properties of the oxygen atom. As a result, the stable and easily accessible nitro-substituted Hoveyda-Grubbs catalyst has found a number of successful applications in various research and industrial laboratories. Some other EWG-activated Hoveyda-type catalysts are commercially available. The results described herewith demonstrate that the activity of ruthenium (Ru) metathesis catalysts can be enhanced by introduction of EWGs without detriment to catalysts stability. Equally noteworthy is the observation that different Ru catalysts turned out to be optimal for different applications. This shows that no single catalyst outperforms all others in all possible applications.

  14. 40 CFR 180.225 - Phosphine; tolerances for residues.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Soybean, seed 0.1 Sunflower, seed 0.1 Sweet potato, roots 0.01 Tangelo 0.01 Tangerine 0.01 Tomato 0.01... Orange, sweet 0.01 Papaya 0.01 Peanut 0.1 Pecan 0.1 Pepper 0.01 Persimmon 0.01 Pistachio 0.1 Rice,...

  15. 40 CFR 180.225 - Phosphine; tolerances for residues.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Soybean, seed 0.1 Sunflower, seed 0.1 Sweet potato, roots 0.01 Tangelo 0.01 Tangerine 0.01 Tomato 0.01... Orange, sweet 0.01 Papaya 0.01 Peanut 0.1 Pecan 0.1 Pepper 0.01 Persimmon 0.01 Pistachio 0.1 Rice,...

  16. 40 CFR 180.225 - Phosphine; tolerances for residues.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Soybean, seed 0.1 Sunflower, seed 0.1 Sweet potato, roots 0.01 Tangelo 0.01 Tangerine 0.01 Tomato 0.01... Orange, sweet 0.01 Papaya 0.01 Peanut 0.1 Pecan 0.1 Pepper 0.01 Persimmon 0.01 Pistachio 0.1 Rice,...

  17. 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

  18. Amine, Alcohol and Phosphine Catalysts for Acyl Transfer Reactions

    NASA Astrophysics Data System (ADS)

    Spivey, Alan C.; Arseniyadis, Stellios

    An overview of the area of organocatalytic asymmetric acyl transfer processes is presented including O- and N-acylation. The material has been ordered according to the structural class of catalyst employed rather than reaction type with the intention to draw mechanistic parallels between the manner in which the various reactions are accelerated by the catalysts and the concepts employed to control transfer of chiral information from the catalyst to the substrates.

  19. (Perchlorato-?O)tris(triphenylphosphine-?P)silver(I)

    PubMed Central

    Cui, Li-Na; Hu, Ke-Yi; Jin, Qiong-Hua; Zhang, Cun-Lin

    2010-01-01

    In the title complex, [Ag(C18H15P)3(ClO4)], the silver coordination environment is dominated by the distorted P3AgO tetrahedron in which AgO = 2.608?(12)? and the AgP bond lengths are 2.5663?(17), 2.5076(16) and 2.5450?(17)?. The perchlorate O-atoms are disordered over two positions in a 0.584?(14):0.416?(14) ratio. PMID:21588119

  20. 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 PO bond is 1.490?(1)?. 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)?]. The CO interaction directs an extended supramolecular arrangement along the a-axis. PMID:26090188

  1. 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 ?-phosphonium enoate ?-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

  2. 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 ...

  3. The electron-poor phosphines P{C6H3(CF3)2-3,5}3 and P(C6F5)3 do not mimic phosphites as ligands for hydroformylation. A comparison of the coordination chemistry of P{C6H3(CF3)2-3,5}3 and P(C6F5)3 and the unexpectedly low hydroformylation activity of their rhodium complexes.

    PubMed

    Clarke, Matthew L; Ellis, Dianne; Mason, Kate L; Orpen, A Guy; Pringle, Paul G; Wingad, Richard L; Zaher, Damien A; Baker, R Tom

    2005-04-01

    The fluoroaryl phosphines P{C6H3(CF3)2-3,5}3 (La) and P(C6F5)3 (Lb) form the complexes trans-[MCl2(La)2] and trans-[MCl2(Lb)2](M = Pd or Pt) which have been isolated and fully characterised. 31P NMR studies of competition experiments show that the stability of trans-[PdCl2L2] is in the order L = Lb< La

  4. 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…

  5. 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.

  6. 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

  7. The ansa-zirconocene [bis(?5-cyclopentadienyl)phenylphosphine]dichloridozirconium(IV)

    PubMed Central

    Bschel, Susanne; Daniliuc, Constantin; Jones, Peter G.; Tamm, Matthias

    2010-01-01

    In the title compound, [Zr(C16H13P)Cl2], the geometry at the metal atom is distorted tetrahedral; the ClZrCl angle is 101.490?(16) and the cyclopentadienyl (Cp) centroids subtend an angle of 122.63?(3) at the Zr atom. The P atom lies 0.474?(3) and 0.496?(3)? out of the planes of the Cp rings. The CPC angle of 91.42?(7) reflects the pincer effect of the two Cp rings. Three CH?Cl, one CH?P, one CH?? and one Cl?P interaction link the molecules to form thick layers parallel to the bc plane. PMID:20203402

  8. Phosphine-Catalyzed Diastereoselective Synthesis of ?-Lactones from Disubstituted Ketenes and ?-Chiral Oxyaldehydes.

    PubMed

    Mondal, Mukulesh; Chen, Shi; Othman, Nabil; Wheeler, Kraig A; Kerrigan, Nessan J

    2015-06-01

    In this article we describe a catalytic procedure for the diastereoselective synthesis of ?-lactones bearing two stereogenic centers, from disubstituted ketenes and ?-chiral oxyaldehydes. Tri-n-butylphosphine was found to be the optimal catalyst in terms of effecting both good yield and diastereoselectivity (dr from 3:1 to 32:1 for 8 examples) in ?-lactone formation. The major isomer of the ?-lactone products was determined to be the anti-diastereomer, and its formation was rationalized by a polar Felkin-Anh model. Involvement of phosphonium enolate intermediates in the reaction mechanism was indicated through reaction monitoring by (31)P NMR spectroscopy. The utility of the methodology is demonstrated by a short synthesis of a (+)-peloruside A synthon. PMID:25938264

  9. 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,...

  10. Assembly of symmetrical and unsymmetrical platinum(II) rollover complexes with bidentate phosphine ligands.

    PubMed

    Maidich, Luca; Zuri, Giuseppina; Stoccoro, Sergio; Cinellu, Maria Agostina; Zucca, Antonio

    2014-10-21

    The reaction of the cyclometalated rollover complex [Pt(bpy-H)(Me)(DMSO)] (bpy-H = cyclometalated 2,2'-bipyridine) with two diphosphines, dppm (1,1-bis(diphenylphosphino)methane) and dppe (1,2-bis(diphenylphosphino)ethane), was investigated. According to the reaction conditions, dppm behaves as a monodentate, bridging or chelated ligand, whereas dppe gave only chelated species. Some aspects of the reactivity of the isolated species were studied, including protonation with [H3O18-crown-6][BF4] and coordination reactions of mononuclear complexes, obtaining, inter alia, rare examples of unsymmetrical organometallic species with bridging dppm. PMID:25162179

  11. 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

  12. 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.

  13. 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

  14. 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.

  15. 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.

  16. Inhibition of human folylpolyglutamate synthetase by diastereomeric phosphinic acid mimics of the tetrahedral intermediate.

    PubMed

    McGuire, John J; Bartley, David M; Tomsho, John W; Haile, William H; Coward, James K

    2009-08-15

    Phosphorus-containing pseudopeptides, racemic at the C-terminal alpha-carbon, are potent mechanism-based inhibitors of folylpolyglutamate synthetase (FPGS). They are mimics of the tetrahedral intermediate postulated to form during FPGS-catalyzed biosynthesis of poly(gamma-l-glutamates). In the present paper, the FPGS inhibitory activity of each diastereomer coupled to three heterocycles is reported. The high R(f) pseudopeptide containing the 5,10-dideazatetrahydropteroyl (DDAH(4)Pte) heterocycle is most potent (K(is) = 1.7 nM). While the heterocyclic portion affects absolute FPGS inhibitory potency, the high R(f) species is more potent in each pair containing the same heterocycle. This species presumably has the same stereochemistry as the natural folate polyglutamate, i.e., (l-Glu-gamma-l-Glu). Unexpectedly, the low R(f) (presumed l-Glu-gamma-d-Glu) species are only slightly less potent (<30-fold) than their diastereomers. Further study of this phenomenon comparing l-Glu-gamma-l-Glu and l-Glu-gamma-d-Glu dipeptide-containing FPGS substrates shows that <1% contamination of commercial d-Glu precursors by l-Glu may give misleading information if l-Glu-gamma-l-Glu substrates have low K(m) values. PMID:19563773

  17. Study on the interaction of amino phosphine ester derivatives with DNA by spectroscopy, modeling and calorimetry

    NASA Astrophysics Data System (ADS)

    Lu, Yan; Wang, Gongke; Tang, Wen; Hao, Xiaoxiao; Xu, Meihua; Li, Xiang

    2011-11-01

    The binding properties of amino phosphate ester derivatives, compound 1 and 2 with calf thymus DNA (CT-DNA) were investigated by UV spectra, fluorescence spectra, molecular modeling and isothermal titration calorimetry (ITC). The intrinsic binding constants Kb of compound 1 and 2 with CT-DNA were determined by fluorescence spectroscopy and ITC, respectively. The results indicated that the two compounds bind to CT-DNA with different binding affinity, which is in the order of compound 1 > compound 2. At the same time, fluorescence spectra suggested that the mechanism of the binding of the two compounds to CT-DNA is a static enhancing type. According to the ethidium bromide displacement experiments, UV spectra, molecular modeling and ITC studies, it can be concluded that compound 1 and 2 are intercalators that can slide into the G-C rich region of CT-DNA. Furthermore, ITC data showed that compound/DNA binding is enthalpy controlled.

  18. 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.

  19. 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

  20. 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

  1. 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

  2. Vibrational spectra and structural dynamic models of arsine-and phosphine-substituted biphenyl

    NASA Astrophysics Data System (ADS)

    lkin, P. M.; Pulin, V. F.; Dzhalmuhambetova, E. A.

    2008-07-01

    Vibrational spectra of biphenylarsine, biphenylphosphine, biphenyldichloroarsine, and biphenyldichlorophosphine are analyzed by the DFT/B3LYP/6-31G(d) method. The fundamental vibrations of these compounds were interpreted based on direct quantum calculations of the geometrical and electronic structure in the anharmonic approximation. Solving the problem in the anharmonic approximation avoids the necessity of using a scaling procedure in predictive calculations.

  3. Chiral phosphinate degradation by the fusarium species: scope and limitation of the process.

    PubMed

    Kmiecik, Natalia; Klimek-Ochab, Magdalena; Brzezi?ska-Rodak, Ma?gorzata; Majewska, Paulina; Zyma?czyk-Duda, Ewa

    2013-01-01

    Biodegradable capacities of fungal strains of Fusarium oxysporum (DSMZ 2018) and Fusarium culmorum (DSMZ 1094) were tested towards racemic mixture of chiral 2-hydroxy-2-(ethoxyphenylphosphinyl) acetic acid-a compound with two stereogenic centres. The effectiveness of decomposition was dependent on external factors such as temperature and time of the process. Optimal conditions of complete mineralization were established. Both Fusarium species were able to biodegrade every isomer of tested compound at 30C, but F. culmorum required 10 days and F. oxysporum 11 days to accomplish the process, which was continuously monitored using the (31)P NMR technique. PMID:24324893

  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. 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

  6. Electron and Hole Transport in a Wide Bandgap Organic Phosphine Oxide for Blue Electrophosphorecsence

    SciTech Connect

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

    2008-02-28

    We report blue phosphorescent organic light-emitting devices (OLEDs) using an ambipolar host, N-(4-diphenylphosphoryl phenyl) carbazole (MPO12), doped with iridium (III) bis[4,6-difluorophenyl)-pyridinato-N,C2]picolinate (FIrpic). The external quantum efficiency and operating voltage is 9.10.1% and 4.8 V, respectively, measured at a brightness of 800 cd/m2 with no outcoupling enhancement. By varying the layer structure of the OLEDs, we show that MPO12 is capable of transporting both electrons and holes, in contrast to previous demonstrations using diphosphine oxides, which only transported electrons. The improved hole transport results in improved device efficiency.

  7. A thiosemicarbazone ligand functionalized by a phosphine group: reactivity toward coinage metal ions.

    PubMed

    Castieiras, Alfonso; Pedrido, Rosa

    2010-04-21

    The reactivity of the phosphino-thiosemicarbazone ligand 2-(2-(diphenylphosphino)benzylidene)-N-ethylthiosemicarbazone (HLPEt) toward M(I) halides (M = Cu, Ag, Au) was studied. The complexes obtained, with formulae [Cu(HLPEt)(2)]Br (1), [Cu(HLPEt)(2)]I.2H(2)O (2), [Ag(HLPEt)(LPEt)].3H(2)O (3), [Au(2)(HLPEt)(2)Cl]Cl.CH(3)OH (4) were satisfactorily characterized by elemental analysis, IR, ESI and (1)H/(31)P NMR. Moreover, we have obtained the crystal structure of the ligand HLPEt and its sulfide oxidized form HLP(S)Et, which represents a new case of desulfurization process in thiosemicarbazone ligands. In addition, we present the crystal structure of the complexes 1 + H(2)O + 3MeOH and [Au(2)(HLPEt)(4)Cl]Cl.3CH(3)OH (5), together with their interesting crystal packing. The complex 5 is an interesting case of a pseudo-chloronium gold(I) complex. The ligand HLPEt and the complexes 3 and 4 display intense luminescence at room temperature. PMID:20354611

  8. Studies on phosphine and phosphonite cationic technetium complexes as potential myocardial imaging agents

    SciTech Connect

    Hirth, W.W.

    1988-01-01

    The ultimate goal of this research is the development of a more effective {sup 99m}Tc myocardial imaging agent. Due to the low molar concentrations of {sup 99m}Tc radiopharmaceuticals, HPLC with radiometric detection is one of the few means available for their analysis and characterization. Reverse phase ion-pair HPLC is the preferred method of analysis for cationic {sup 99m}Tc complexes. Studies are presented which elucidate some of the unusual chromatographic behavior seen during the reverse phase HPLC analysis of these complexes. Analyses of unstable complexes which are susceptible to in vivo redox reactions at the 10{sup {minus}10} to 10{sup {minus}15} M concentration level are described. In vitro prescreening of potential {sup 99m}Tc radiopharmaceuticals is essential to the development of these agents. New analytical techniques are presented which may prove of use in the development of prescreening methods. In vitro chromatographic analysis of the serum protein binding behavior of some cationic {sup 99m}T complexes provides an explanation of the unusual biological properties of these complexes. The synthesis of two groups of {sup 99}Tc and {sup 99m}Tc complexes are described.

  9. 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…

  10. 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

  11. Structural and conformational study of pentacarbonyl and phosphine substituted Fischer alkoxy- and aminocarbene complexes of molybdenum

    NASA Astrophysics Data System (ADS)

    Landman, Maril; Levell, Tamzyn J.; Conradie, Marrigje M.; van Rooyen, Petrus H.; Conradie, Jeanet

    2015-04-01

    The synthesis and selected crystal structures of a series of nine (eight are reported for the first time) Mo(0) Fischer carbene complexes of the formula [(CO)3(L,L?)Modbnd C(Y)(2-furyl)] with Y = OEt, NH2 or NHCy; L,L? = CO,CO; PPh3,CO; dppe (1,2-bis(diphenylphosphino)ethane) are reported. DFT quantum chemical calculations on the different possible isomers and conformers of the Mo carbene complexes yielded more than one stable conformation for each complex. The small energy difference between some of the conformers of the same complex indicates that in some cases more than one conformer should be experimentally feasible. The crystal structures of the complexes in the solid state correspond favourably with the DFT calculated structures. Natural bond orbital second-order perturbation theory calculations indicated donor-acceptor interactions between a furyl oxygen lone pair and the antibonding orbital of the Nsbnd H for the Mo aminocarbene complexes, in agreement with the preference for the syn conformation for the Mo aminocarbene complexes in the solid state structures.

  12. Thioiminium and thiaphospholanium derived from acetonitrile via nickel(ii)-(2-mercaptophenyl)phosphine complexation.

    PubMed

    Chang, Hao-Ching; Hsu, Yu-Chen; Chen, Chia-Hui; Kuo, Ting-Shen; Lee, Way-Zen

    2015-12-28

    [Ni(P(o-C6H4S)(o-C6H4SC(CH3)[double bond, length as m-dash]NH2)(C6H5))2](ClO4)2 (2) with two thioiminium functionalities is derived from CH3CN solvent under anhydrous conditions. Moreover, thiaphospholanium salts, [(C6H5)P(C6H4SC(CH3)(NHCOCH3))(o-C6H4SH)](ClO4) (3) and [(C6H5)2-P(C6H4SC(CH3)(NH3))](ClO4)2 (5), can be obtained through a similar Pinner-type nitrile activation. These results demonstrate the possible intermediate of enzymatic nitrile transformation and also provide an approach to the preparation of 2-amino-1,3-benzothiaphospholanium derivatives. PMID:26549142

  13. 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

  14. Palladium-catalyzed aminations of aryl halides with phosphine-functionalized imidazolium ligands.

    PubMed

    Shi, Ji-cheng; Yang, Pengyu; Tong, Qingsong; Jia, Li

    2008-02-21

    A series of 1-(2-diphenylphosphinoferrocenyl)ethyl-3-substituted imidazolium iodides [3-substituent = methyl (1a); isopropyl (1b); tert-butyl (1c); 1-adenosyl (1d); cyclohexyl (1e); 2,6-dimethylphenyl (1f); 2,4,6-trimethylphenyl (1g); 2,6-diisopropylphenyl (1h)] have been prepared and evaluated as ligands in the palladium-catalyzed aminations of aryl halides with various amines. The scope of the coupling process was carried out for various aryl bromides and chlorides with the catalysts generated in situ from a mixture of Pd(OAc)2 and in the presence of a base. NaO t Bu was found the choice of base in combination with dioxane, toluene, or DME as solvent, although NaOH or Cs2CO3 promoted the coupling of 4-bromotoluene with morpholine in moderate conversion. The steric hindrance from the 3-substituent of imidazolium in the hybrid-bidentate chelating system was found to be only beneficial to the substrates without ortho-substituents. The more sterically hindered 1d or 1h promoted the coupling of bromobenzene with morpholine in nearly quantitative conversion with 0.2 mol% of palladium loading in the presence of NaO t Bu at 110 degrees C, and 94% of conversion was afforded with the less sterical demanding 1a for a longer time. However, for the substrates with ortho-substituents, higher conversions were achieved with 1a. The Pd(OAc)2/1d catalytic system was also active for deactivated aryl chloride, and 71% isolated yield for the desired product was realized for coupling of 4-chloroanisole with morpholine at 2 mol% of catalyst loading. The developed catalyst system has been applied successfully to the synthesis of a key building block for a type of functional polymers. PMID:18259628

  15. 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

  16. High-spin manganese(II) complexes of an amido/bis(phosphine) PNP ligand.

    PubMed

    Bacciu, Deborha; Chen, Chun-Hsing; Surawatanawong, Panida; Foxman, Bruce M; Ozerov, Oleg V

    2010-06-01

    Syntheses of several Mn complexes supported by a monoanionic amido/bis(phosphino) PNP ligand (PNP = [2-P(CHMe(2))(2)-4-MeC(6)H(3)](2)N) from anhydrous MnCl(2) are reported. Treatment of (PNP)Li (2) with MnCl(2) in tetrahydrofuran (THF) led to isolation of either (PNP)Mn(mu-Cl)(2)Li(THF)(2) (5) or (PNP)MnCl (6), depending on the workup. Reaction of 6 with 2 equiv of MeLi resulted in isolation of (PNP)Mn(mu-Me)(2)Li(THF)(2) (7) that is structurally similar to 5. Reduction of 6 in the presence of pyridine produced material analytically consistent with (PNP)Mn(py)(3) (8), whereas reduction in the presence of 2,2'-bipyridine gave fully characterized (PNP)Mn(bipy) (9). Compounds 5 and 7 display magnetic moments indicative of high-spin Mn(II) (S = 5/2). The magnetic moment of 9 (S = 2) was interpreted as an antiferromagnetic combination of a high-spin Mn(II) center and a singly reduced bipyridine ligand. Addition of a single CO ligand to 9 generated diamagnetic, low-spin (PNP)Mn(bipy)(CO) (10). Solid-state structures of 5, 7, 9, and 10 were determined by X-ray diffraction methods and used in conjunction with density functional theory studies to analyze the electronic nature of the (PNP)Mn complexes under study. PMID:20441168

  17. Chain-End-Functionalized Polyphosphazenes via a One-Pot Phosphine-Mediated Living Polymerization

    PubMed Central

    Wilfert, Sandra; Henke, Helena; Schoefberger, Wolfgang; Brggemann, 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 ?-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

  18. 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

  19. 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 (?max480 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.

  20. 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

  1. A highly active phosphine-borane organocatalyst for the reduction of CO2 to methanol using hydroboranes.

    PubMed

    Courtemanche, Marc-Andr; Lgar, Marc-Andr; Maron, Laurent; Fontaine, Frdric-Georges

    2013-06-26

    In this work, we report that organocatalyst 1-Bcat-2-PPh2-C6H4 ((1); cat = catechol) acts as an ambiphilic metal-free system for the reduction of carbon dioxide in presence of hydroboranes (HBR2 = HBcat (catecholborane), HBpin (pinacolborane), 9-BBN (9-borabicyclo[3.3.1]nonane), BH3SMe2 and BH3THF) to generate CH3OBR2 or (CH3OBO)3, products that can be readily hydrolyzed to methanol. The yields can be as high as 99% with exclusive formation of CH3OBR2 or (CH3OBO)3 with TON (turnover numbers) and TOF (turnover frequencies) reaching >2950 and 853 h(-1), respectively. Furthermore, the catalyst exhibits "living" behavior: once the first loading is consumed, it resumes its activity on adding another loading of reagents. PMID:23750670

  2. Interaction of hydrated protons with octyl-phenyl-N,N-diisobutylcarbamoylmethyl phosphine oxide (CMPO): NMR and theoretical study.

    PubMed

    K?, Jaroslav; Dybal, Ji?; Makrlk, Emanuel; Va?ura, 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 ? = 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 ? < 0.75. Analyzing the collective dependence of (13)C and (31)P NMR chemical shifts on ? 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 ? pulses in the mixtures with ? = 0.4-0.8. The following exchange correlation times were obtained: ?(10) = 2.35 10(-5), ?(20) = 0.82 10(-4), ?(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

  3. 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

  4. Deoxygenation of some ?-dicarbonyl compounds by tris(diethylamino)phosphine in the presence of fullerene C60.

    PubMed

    Romanova, Irina P; Bogdanov, Andrey V; Mironov, Vladimir F; Shaikhutdinova, Gulnara R; Larionova, Olga A; Latypov, Shamil K; Balandina, Alsu A; Yakhvarov, Dmitry G; Gubaidullin, Aidar T; Saifina, Alina F; Sinyashin, Oleg G

    2011-04-15

    The reactions of such cyclic ?-diketones as acenaphthenequinone, aceanthrenequinone, and N-alkylisatins, with hexaethyltriaminophosphine in the presence of the fullerene C(60), lead to the formation of methanofullerene derivatives under mild conditions. This process proceeds via deoxygenation of the dicarbonyl compound by the P(III) derivative and is likely to involve the intermediate formation of ?-ketocarbenes. The structure of some methanofullerenes has been confirmed by NMR and XRD. The electrochemical behavior of the methanofullerenes was also investigated. PMID:21391680

  5. 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.

  6. An ambipolar phosphine oxide-based host for high power efficiency blue phosphorescent organic light emitting devices

    SciTech Connect

    Polikarpov, Evgueni; Swensen, James S.; Chopra, Neetu; So, Franky; Padmaperuma, Asanga B.

    2009-06-01

    We report blue electrophosphorescent organic light emitting devices (OLEDs) with a new ambipolar host material, 4-(diphenylphosphoryl)-N,N-diphenylaniline (HM-A1), doped with the blue phosphor iridium (III) bis[(4,6-difluorophenyl)-pyridinato-N,C2]picolinate (FIrpic). The ambipolar nature of the host was verified using single carrier devices. The power efficiency of devices that employed 2,8-bis(diphenylphosphoryl)dibenzothiophene (PO15) as the electron transport layer showed optimized device performance when the electron transport layer thickness was 500 , giving a peak power efficiency of 46 lm/W (corresponding external quantum efficiency of 17.1%). The external quantum efficiency and power efficiency at the brightness of 800 Cd/m2 were measured with no light outcoupling enhancement and found to be 15.4% and 26 lm/W, respectively.

  7. 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

  8. 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

  9. 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 25C). The hydrogen addition product exists as three nearly isoenergetic isomers 4A4C, 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

  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. Reactivity of Phosphanylphosphinidene Complex of Tungsten(VI) toward Phosphines: A New Method of Synthesis of catena-Polyphosphorus Ligands.

    PubMed

    Grubba, Rafa?; Ordyszewska, Anna; Kaniewska, Kinga; Ponikiewski, ?ukasz; Chojnacki, Jaros?aw; Gudat, Dietrich; Pikies, Jerzy

    2015-09-01

    The reactivity of an anionic phosphanylphosphinidene complex of tungsten(VI), [(2,6-i-Pr2C6H3N)2(Cl)W(?(2)-t-Bu2P?P)]Li3DME toward PMe3, halogenophosphines, and iodine was investigated. Reaction of the starting complex with Me3P led to formation of a new neutral phosphanylphosphinidene complex, [(2,6-i-Pr2C6H3N)2(Me3P)W(?(2)-t-Bu2P?P)]. Reactions with halogenophosphines yielded new catena-phosphorus complexes. From reaction with Ph2PCl and Ph2PBr, a complex with an anionic triphosphorus ligand t-Bu2P-P((-))-PPh2 was isolated. The main product of reaction with PhPCl2 was a tungsten(VI) complex with a pentaphosphorus ligand, t-Bu2P-P((-))-P(Ph)-P((-))-P-t-Bu2. Iodine reacted with the starting complex as an electrophile under splitting of the P-P bond in the t-Bu2P?P unit to yield [(1,2-?-t-Bu2P-P-P-t-Bu2)W(2,6-i-Pr2C6H3N)2Cl], t-Bu2PI, and phosphorus polymers. The molecular structures of the isolated products in the solid state and in solution were established by single crystal X-ray diffraction and NMR spectroscopy. PMID:26287312

  12. 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.

  13. 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

  14. Relative Lability and Chemoselective Transmetallation of NHC in Hybrid Phosphine-NHC Ligands: Access to Heterometallic Complexes.

    PubMed

    Simler, Thomas; Braunstein, Pierre; Danopoulos, Andreas A

    2015-11-01

    The relative lability and transmetallation aptitude of trialkylphosphine and NHC donors, integrated in semi-rigid hybrid ligands attached to [Ag4Br4] pseudo-cubanes, lies in favor of the NHC and is used to selectively access unprecedented NHC complexes with heterobimetallic cores, such as Ag-Cu (4(Cy)) and Ag-Ir (5(tBu)). These can be viewed as an arrested state before the full transmetallation of both donors, which gives the homodinuclear Cu (3(Cy)) and Ir (6(Cy)) complexes. The observed NHC transmetallation aptitude and reactivity urges caution in the common notion that views the NHC as a universal spectator. PMID:26463419

  15. Ligand reactivity in diarylamido/bis(phosphine) PNP complexes of Mn(CO)3 and Re(CO)3.

    PubMed

    Radosevich, Alexander T; Melnick, Jonathan G; Stoian, Sebastian A; Bacciu, Deborha; Chen, Chun-Hsing; Foxman, Bruce M; Ozerov, Oleg V; Nocera, Daniel G

    2009-10-01

    The syntheses of meridionally ligated tricarbonyl complexes (PNP)Mn(CO)(3) and (PNP)Re(CO)(3) are described (PNP = [2-P(CHMe(2))(2)-4-MeC(6)H(3)](2)N(-)). Cyclic voltammograms show reversible one-electron redox couples for both parent compounds (-0.34 V vs Cp(2)Fe(0/+) for (PNP)Mn(CO)(3), -0.25 V vs Cp(2)Fe(0/+) for (PNP)Re(CO)(3)), and chemical oxidation with AgOTf results in formation of the corresponding paramagnetic triflate salts [(PNP)Mn(CO)(3)]OTf and [(PNP)Re(CO)(3)]OTf. Electron paramagnetic resonance spectra and computational results indicate that this event is primarily ligand centered; allylation of the organic ligand moiety of [(PNP)Mn(CO)(3)]OTf with allyltributylstannane is consistent with this assignment. The oxidation (PNP)Mn(CO)(3) to [(PNP)Mn(CO)(3)]OTf results in a shift in average CO stretching frequency of 30 cm(-1); protonation of (PNP)Mn(CO)(3) with TfOH to form [(PNHP)Mn(CO)(3)]OTf results in a similar magnitude shift. PMID:19736909

  16. 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.

  17. 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.

  18. Selective extraction of metal ions with polymeric extractants by ion exchange/redox

    DOEpatents

    Alexandratos, Spiro D. (Knoxville, TN)

    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.

  19. 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.

  20. 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

  1. 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.

  2. 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

  3. Extraction of Am(III) and Fe(III) by selected dihexyl N,N-dialkylcarbamoylmethyl-phosphonates, -phosphinates and -phospine oxides from nitrate media

    SciTech Connect

    Kalina, D.G.; Horwitz, E.P.; Kaplan, L.; Muscatello, A.C.

    1981-01-01

    A series of neutral bifunctional extractants related to dihexyl N,N,-diethylcarbamoylmethylphosphonate (DHDECMP) have been prepared and studied for the liquid-liquid extraction of Am(III) and Fe(III) from nitrate solutions. Changes in the steric bulk of the substitutent alkyl chains and in the electronegativity of the groups attached to the phosphoryl center in these compounds have brought about large changes in distribution ratios and selectivities for the extraction of these metals. Comparisons of these extractants to related monofunctional phosphorus-based compounds have revealed that these bifunctional species behave as monodentate, rather than chelating, extractants. The presence of the carbamoyl portion of the extractant molecules is important not for coordination to the metal, but for the ability to buffer the extractant against the effects of HNO/sub 3/. 9 figures, 2 tables.

  4. 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

  5. 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

  6. Partitioning of Eu(III) between acidic aqueous Al(NO{sub 3}){sub 3} and tri-n-octyl phosphine oxide

    SciTech Connect

    Shafer, J.C.; Harrington, R.C.; Nash, K.L.

    2008-07-01

    As the Hanford site undergoes remediation, significant economies could be realized if aluminum is kept from High-Level Waste glass. An acidic scrub of the Hanford sludge could enhance Al removal; however, a caveat is the potential mobilization of transuranic elements, which would require a secondary cleanup of the Al/Cr waste stream. Previous solvent extraction (SX) studies have shown that >99% of the Eu and U can be extracted from simulated acidic Al/Cr waste. This study examines the use of extraction chromatographic methods. Results indicate the systems behave comparably and either method could be considered for Hanford clean-up purposes. (authors)

  7. Synthesis of chiral 2,2{prime}-bis(diphenylphosphino)-1,1{prime}-binaphthyl (BINAP) via a novel nickel-catalyzed phosphine insertion

    SciTech Connect

    Cai, D.; Payack, J.F.; Bender, D.R.

    1994-11-18

    2,2{prime}-Bis(diphenylphosphino)-1,1{prime}binaphthyl (BINAP), introduced in the early 1980`s, has become one of the most successful chiral ligands for catalytic asymmetric induction. Its wide application has been somewhat limited due to the scarce supply and expense of BINAP and up to now, there has been only one reported practical synthesis of chiral BINAP.

  8. 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.

  9. 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.

  10. Synthesis of Ruthenium Carbonyl Complexes with Phosphine or Substituted Cp Ligands, and Their Activity in the Catalytic Deoxygenation of 1,2-Propanediol

    SciTech Connect

    Ghosh, Prasenjit; Fagan, Paul J.; Marshall, William J.; Hauptman, Elisabeth; Bullock, R. Morris

    2009-07-20

    A ruthenium hydride with a bulky substituted Cp ligand, (CpiPr4)Ru(CO)2H (CpiPr4 = C5(i-C3H7)4H) was prepared from the reaction of Ru3(CO)12 with 1,2,3,4-tetraisopropylcyclopentadiene. The molecular structure of (CpiPr4)Ru(CO)2H was determined by x-ray crystallography. The ruthenium hydride complex (C5Bz5)Ru(CO)2H (Bz = CH2Ph) was similarly prepared. The Ru-Ru bonded dimer, [(1,2,3-trimethylindenyl)Ru(CO)2]2, was produced from the reaction of 1,2,3-trimethylindene with Ru3(CO)12, and protonation of this dimer with HOTf gives {[(1,2,3-trimethylindenyl)Ru(CO)2]2(? H)}+OTf . A series of ruthenium hydride complexes CpRu(CO)(L)H [L = P(OPh)3, PCy3, PMe3, P(p C6H4F)3] were prepared by reaction of Cp(CO)2RuH with added L. Protonation of (CpiPr4)Ru(CO)2H, Cp*Ru(CO)2H or CpRu(CO)[P(OPh)3]H by HOTf 80 C led to equilibria with the cationic dihydrogen complexes, but H2 was released at higher temperatures. Protonation of CpRu[P(OPh)3]2H with HOTf gave an observable dihydrogen complex, {CpRu[P(OPh)3]2(?2 H2)}+OTf that was converted at -20 C to the dihydride complex {CpRu[P(OPh)3]2(H)2}+OTf . 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 H2 (750 psi) at 110 C. This work was supported by the U.S. Department of Energy's (DOE) Office of Basic Energy Sciences, Chemical Sciences program. Pacific Northwest National Laboratory is operated by Battelle for DOE.

  11. Brilliant photoluminescence and triboluminescence from ternary complexes of Dy(III) and Tb(III) with 3-phenyl-4-propanoyl-5-isoxazolonate and a bidentate phosphine oxide coligand.

    PubMed

    Biju, S; Gopakumar, N; Bnzli, J-C G; Scopelliti, R; Kim, H K; Reddy, M L P

    2013-08-01

    Three new lanthanide heterocyclic ?-diketonate complexes [Dy(PPI)3(EtOH)2] (1), [Dy(PPI)3(DPEPO)] (2), and [Tb(PPI)3(DPEPO)] (3) [where HPPI = 3-phenyl-4-propanoyl-5-isoxazolone and DPEPO = bis(2-(diphenylphosphino)phenyl)ether oxide] have been synthesized and fully characterized. Single-crystal X-ray diffraction analyses reveal that these complexes are mononuclear and that the central Ln(III) ion is coordinated to eight oxygen atoms that are provided by three bidentate ?-diketonate ligands and ethanol or bidentate DPEPO in a distorted square antiprismatic geometry. These complexes have high molar absorption coefficients (up to 3 10(4) M(-1) cm(-1) at 285 nm) and display strong visible and, for Dy(III), NIR luminescence upon irradiation at the ligand-centered band in the range 250-350 nm. The emission quantum yields and the luminescence lifetimes at room temperature are 3 0.5% and 15 1 ?s for 1, 12 2% and 33 1 ?s for 2, and 42 6% and 795 1 ?s for 3. Moreover, the crystals of 2 and 3 exhibit brilliant triboluminescence, visible in daylight. PMID:23848056

  12. Unexpected metal-induced isomerisms and phosphoryl migrations in Pt(II) and Pd(II) complexes of the functional phosphine 2-(bis(diphenylphosphino)methyl)-oxazoline.

    PubMed

    Zhang, Shuanming; Pattacini, Roberto; Braunstein, Pierre

    2011-04-18

    The reaction of the functional diphosphine 1 [1 = 2-(bis(diphenylphosphino)methyl-oxazoline] with [PtCl(2)(NCPh)(2)] or [PdCl(2)(NCPh)(2)], in the presence of excess NEt(3), affords [Pt{(Ph(2)P)(2)CC(NCH(2)CH(2)O)}(2)] ([Pt(1(-H)-P,P)(2)], 3a) and [Pd{(Ph(2)P)(2)CC(NCH(2)CH(2)O)}(2)] ([Pd(1(-H)-P,P)(2)], 3b), respectively, in which 1(-H) is (oxazoline-2-yl)bis(diphenylphosphino)methanide. The reaction of 3b with 2 equiv of [AuCl(tht)] (tht = tetrahydrothiophene) afforded [Pd(1(-H)-P,N)(2)(AuCl)(2)] (4), as a result of the opening of the four-membered metal chelate since ligand 1(-H), which was P,P-chelating in 3b, behaves as a P,N-chelate toward the Pd(II) center in 4 and coordinates to Au(I) through the other P donor. In the absence of a base, the reaction of ligand 1 with [PtCl(2)(NCPh)(2)] in MeCN or CH(2)Cl(2) afforded the isomers [Pt{(Ph(2)P)(2)C?C(OCH(2)CH(2)NH)}(2)]Cl(2) ([Pt(1'-P,P)(2)]Cl(2) (5), 1' = 2-(bis(diphenylphosphino)methylene)-oxazolidine) and [Pt{(Ph(2)P)(2)C?C(OCH(2)CH(2)NH)}{Ph(2)PCH?C(OCH(2)CH(2)N(PPh(2))}]Cl(2) ([Pt(1'-P,P)(2'-P,P)]Cl(2) (6), 2' = (E)-3-(diphenylphosphino)-2-((diphenylphosphino)methylene)oxazolidine]. The P,P-chelating ligands in 5 result from a tautomeric shift of the C-H proton of 1 to the nitrogen atom, whereas the formation of one of the P,P-chelates in 6 involves a carbon to nitrogen phosphoryl migration. The reaction of 5 and 6 with a base occurred by deprotonation at the nitrogen to afford 3a and [Pt{(Ph(2)P)(2)CC(NCH(2)CH(2)O)}{Ph(2)PCH?COCH(2)CH(2)N(PPh(2))}]Cl ([Pt(1(-H)-P,P)(2'-P,P)]Cl (7)], respectively. In CH(2)Cl(2), an isomer of 3a, [Pt{Ph(2)P)(2)CC(NCH(2)CH(2)O)}{Ph(2)PC(PPh(2))?COCH(2)CH(2)N}] ([Pt(1(-H)-P,P)(1(-H)-P,N)] (8)), was obtained as a side product which contains ligand 1(-H) in two different coordination modes. Complexes 3b4CH(2)Cl(2), 4CHCl(3), 62.5CH(2)Cl(2), and 8CH(2)Cl(2) have been structurally characterized by X-ray diffraction. PMID:21405088

  13. Spirobifluorene-2,7-dicarbazole-4'-phosphine Oxide as Host for High-Performance Single-Layer Green Phosphorescent OLED Devices.

    PubMed

    Thiery, Sbastien; Tondelier, Denis; Geffroy, Bernard; Jacques, Emmanuel; Robin, Malo; Mtivier, Rmi; Jeannin, Olivier; Rault-Berthelot, Jolle; 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

  14. Chiral thiahelicene-based alkyl phosphine-borane complexes: synthesis, X-ray characterization, and theoretical and experimental investigations of optical properties.

    PubMed

    Dova, Davide; Cauteruccio, Silvia; Prager, Stefan; Dreuw, Andreas; Graiff, Claudia; Licandro, Emanuela

    2015-04-17

    Chiral helical-based phosphanes are challenging and promising ligands, with a great potential for the generation of both organic and organometallic catalysts. We report here the preparation of novel chiral thiahelicene-based alkyl phosphanes, isolated and characterized as air-stable borane adducts, and the investigation of their experimental and theoretical (chir)optical properties. X-ray characterization of a mono- and a disubstituted derivative as a racemic mixture has been performed, which confirms the influence of the number and nature of substituents on the flexibility of the helix. In addition, the absolute configuration inferred from CD spectra of the two enantiomers of a diborane complex has been established from X-ray analysis. State-of-the-art quantum chemical calculations of vibrationally resolved spectra allow, for the first time, for an unambiguous assignment of the experimentally observed peaks in linear absorption and circular dichroism spectra to excited electronic states of this class of thiahelicene phosphorus derivatives. PMID:25774697

  15. New alkyl derivatives phosphine sulfonate (P-O) ligands. Catalytic activity in Pd-catalysed Suzuki-Miyaura reactions in water.

    PubMed

    Garca Surez, Eduardo J; Ruiz, Aurora; Castilln, Sergio; Oberhauser, Werner; Bianchini, Claudio; Claver, Carmen

    2007-07-21

    Two novel bis(o-methoxyphenyl) phosphinoalkylsulfonate (P-O) ligands have been prepared through a new and sustainable synthetic route; they are air stable as well as water soluble and have been applied in Pd-catalysed Suzuki-Miyaura cross-coupling reactions in neat water in conjunction with microwave heating. PMID:17607399

  16. 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

  17. 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

  18. 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.

  19. 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

  20. Enzymatic synthesis of organophosphorus compounds

    NASA Astrophysics Data System (ADS)

    Kolodiazhnyi, Oleg I.

    2011-09-01

    Data on biocatalytic methods for the preparation of chiral organophosphorus compounds are generalized and described systematically. Various examples of enzymatic and microbiological synthesis of hydroxyphosphonates, aminophosphonates, phosphinites, phosphine oxides and tertiary phosphines are discussed. The bibliography includes 154 references.

  1. 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

  2. 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.

  3. 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.

  4. 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

  5. The [MoFe3S4]2+ oxidation state: synthesis, substitution reactions, and structures of phosphine-ligated cubane-type clusters with the S=2 ground state.

    PubMed

    Xi, Bin; Holm, R H

    2011-07-01

    The cluster [(Tp)MoFe(3)S(4)(PEt(3))(3)](1+) containing the cubane-type [MoFe(3)(?(3)-S)(4)](2+) reduced core undergoes facile ligand substitution reactions at the iron sites leading to an extensive set of mono- and disubstituted species [(Tp)MoFe(3)S(4)(PEt(3))(3-n)L(n)](1-n) with L = halide, N(3)(-), PhS(-), PhSe(-), R(3)SiO(-), and R(3)SiS(-) and n = 1 and 2. Structures of 10 members of the set are reported. For two representative clusters, Curie behavior at 2-20 K indicates a spin-quintet ground state. Zero-field Mo?ssbauer spectra consist of two doublets in a 2:1 intensity ratio. (57)Fe isomer shifts are consistent with the mean oxidation state Fe(3)(2.33+) arising from electron delocalization of the mixed-valence oxidation state description [Mo(3+)Fe(3+)Fe(2+)(2)]. Reaction of [(Tp)MoFe(3)S(4)(PEt(3))(2)Cl] with (Me(3)Si)(2)S affords [(Tp)MoFe(3)S(4)(PEt(3))(2)(SSiMe(3))], a likely first intermediate in the formation of the tricluster compound {[(Tp)MoFe(3)S(4)(PEt)(2)](3)S}(BPh(4)) from the reaction of [(Tp)MoFe(3)S(4)(PEt(3))(3)](BPh(4)) and NaSSiMe(3) in tetrahydrofuran (THF). The tricluster consists of three cluster units bound to a central ?(3)-S atom in a species of overall C(3) symmetry. Relatively few clusters in the [MoFe(3)S(4)](2+) oxidation state have been prepared compared to the abundance of clusters in the oxidized [MoFe(3)S(4)](3+) state. This work is the first comprehensive study of the [MoFe(3)S(4)](2+) state, one conspicuous feature of which is its ability to bind hard and soft ?-donors and strong to weak ?-acid ligands. (Tp = tris(pyrazolyl)hydroborate(1-)). PMID:21648449

  6. Solid-state synthesis and characterization of ?-alkane complexes, [Rh(L2)(?(2),?(2)-C7H12)][BAr(F)4] (L2 = bidentate chelating phosphine).

    PubMed

    Pike, Sebastian D; Chadwick, F Mark; Rees, Nicholas H; Scott, Mark P; Weller, Andrew S; Krmer, Tobias; Macgregor, Stuart A

    2015-01-21

    The use of solid/gas and single-crystal to single-crystal synthetic routes is reported for the synthesis and characterization of a number of ?-alkane complexes: [Rh(R2P(CH2)nPR2)(?(2),?(2)-C7H12)][BAr(F)4]; R = Cy, n = 2; R = (i)Pr, n = 2,3; Ar = 3,5-C6H3(CF3)2. These norbornane adducts are formed by simple hydrogenation of the corresponding norbornadiene precursor in the solid state. For R = Cy (n = 2), the resulting complex is remarkably stable (months at 298 K), allowing for full characterization using single-crystal X-ray diffraction. The solid-state structure shows no disorder, and the structural metrics can be accurately determined, while the (1)H chemical shifts of the RhH-C motif can be determined using solid-state NMR spectroscopy. DFT calculations show that the bonding between the metal fragment and the alkane can be best characterized as a three-center, two-electron interaction, of which ?CH ? Rh donation is the major component. The other alkane complexes exhibit solid-state (31)P NMR data consistent with their formation, but they are now much less persistent at 298 K and ultimately give the corresponding zwitterions in which [BAr(F)4](-) coordinates and NBA is lost. The solid-state structures, as determined by X-ray crystallography, for all these [BAr(F)4](-) adducts are reported. DFT calculations suggest that the molecular zwitterions within these structures are all significantly more stable than their corresponding ?-alkane cations, suggesting that the solid-state motif has a strong influence on their observed relative stabilities. PMID:25506741

  7. Ordered interface mesoporous immobilized Pd pre-catalyst: En/Pd complexes embedded inside the SBA-15 as an active, reusable and selective phosphine-free hybrid catalyst for the water medium Heck coupling process.

    PubMed

    Rostamnia, Sadegh; Liu, Xiao; Zheng, Dan

    2014-10-15

    A series of Pd-complexes of amine and diamine ligands embedded into the ordered silica mesoporous (PdX2@SBA-15/NY, Y=1, 2) are synthesized. Among them, the covalently bonded Pd(OAc)2/ethylenediamine complex into the SBA-15 exhibit higher activity and selectivity toward Mizoroki-Heck cross-coupling reaction. The Pd(OAc)2@SBA-15/En pre-catalyst could be separated easily from reaction products and used repetitively several times, showing the superiority over the homogeneous catalysts for industrial and chemical applications. PMID:25084229

  8. On-column tris(2-carboxyethyl)phosphine reduction and IC5-maleimide labeling during purification of a RpoC fragment on a nickel-nitrilotriacetic acid Column.

    PubMed

    Bergendahl, Veit; Anthony, Larry C; Heyduk, Tomasz; Burgess, Richard R

    2002-08-15

    Fluorescence labeling of proteins has become increasingly important since fluorescent techniques like FRET and fluorescence polarization are now commonly used in protein binding studies, proteomics, and for high-throughput screening in drug discovery. In our efforts to study the binding of the beta(')-subunit from Escherichia coli RNA polymerase (RNAP) to sigma70, we synthesized a fluorescent-labeled beta(')-fragment (residues 100-309) in a very convenient way, that could be used as a general protocol for hexahistidine-tagged proteins. By performing all the following steps, purification, reduction, derivatization with IC5-maleimide, and free dye removal while the protein was bound to the column, we were able to reduce the procedure time significantly and at the same time achieve better labeling efficiency and quality. The beta(')-fragment with a N-terminal His(6)-tag was purified from inclusion bodies and could be refolded prior to or after binding to a Ni-NTA affinity column. Reduction prior to labeling was achieved with TCEP that does not interfere with Ni-NTA chemistry. The labeled beta(')-fragment was tested with sigma70 that was labeled with an europium-based fluorophore for binding in a electrophoretic mobility-shift assay. The sigma-to-core protein interaction in bacterial RNA polymerase offers a potentially specific target for drug discovery, since it is highly conserved among the eubacteria, but differs significantly from eukaryotes. PMID:12202256

  9. 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

  10. 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.

  11. Conjugate and method for forming aminomethyl phosphorus conjugates

    SciTech Connect

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

    1999-09-07

    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.

  12. 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.…

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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

  20. Brnsted 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; Sjberg, 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

  1. 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, Nol; Lavigne, Guy; Ustynyuk, Nikolai A

    2015-05-18

    Half-sandwich manganese methylenephosphonium complexes [Cp(CO)2Mn(?(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(?(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

  2. Analysis and modeling of low pressure chemical vapor deposition of phosphorus-doped polysilicon in commercial scale reactor

    NASA Astrophysics Data System (ADS)

    Shimizu, Ryosuke; Ogino, Masaaki; Sugiyama, Masakazu; Shimogaki, Yukihiro

    2004-07-01

    In a commercial scale low pressure chemical vapor deposition (CVD) reactor, we analyzed the elementary reaction of silane based CVD with the doping gas of phosphine. The variation of conductivity in the radial direction over a monitor wafer became significant as the phosphine gas partial pressure decreased, and it reached up to about 30% at 6.510-4 Pa. The radial distribution of phosphorus fraction in a film, however, was smaller than 7%. On the basis of the diffusion model of chemical species into the wafer gaps, we found that the sticking probability of phosphine is 2-510-5, which is 1 order of magnitude larger than the one of silane. The reaction kinetics of both silane and phosphine seems almost linear, but slight nonlinearity at high phosphine concentration range was also indicated. .

  3. Recent advances in synthesis of P-BH3 compounds.

    PubMed

    Alayrac, Carole; Lakhdar, Sami; Abdellah, Ibrahim; Gaumont, Annie-Claude

    2015-01-01

    This chapter is dedicated to the main achievements since 2007 regarding the synthesis of BH3-phosphorus complexes. Among this class of compounds, phosphine-boranes are the most studied derivatives, mainly as valuable surrogates of phosphines, enabling easy handling and purification. In contrast, metal phosphido-boranes have so far only been considered as in situ intermediates in the P-functionalization of secondary phosphine-boranes. Thorough investigations of their structures as well as their chemical properties have recently been reported. Besides phosphine-boranes and their phosphides, new families of phosphorus-BH3 complexes, have emerged as useful precursors of new structures in the asymmetric series. New routes toward optically active phosphinous-acid boranes and their esters were developed and applied to the synthesis of enantiopure P-stereogenic secondary and tertiary phosphine-boranes. The stereoselective synthesis of P-stereogenic aminophosphine-boranes, precursors of a new class of chiral ligands, has been reported. Studies dealing with the synthesis and reactivity of phosphonite-boranes were successfully applied to the development of efficient syntheses of functionalized H-phosphinates, compounds difficult to access by other routes. PMID:25504072

  4. 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

  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 of ?-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 ?-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

  7. Synthesis and structural analysis of the first nanosized platinum-gold carbonyl/phosphine cluster, Pt13[Au2(PPh3)2]2(CO)10(PPh3)4, containing a Pt-centered [Ph3PAu-AuPPh3]-capped icosahedral Pt12 cage.

    PubMed

    de Silva, Namal; Dahl, Lawrence F

    2005-12-26

    The preparation and molecular structure of the initial nanosized platinum-gold carbonyl cluster, Pt(13)[Au(2)(PPh(3))(2)](2)(CO)(10)(PPh(3))(4) (1), are described. A comparative analysis reveals its pseudo-D(2)(h) geometry, consisting of a centered Pt(13) icosahedron encapsulated by two centrosymmetrically related bidentate [Ph(3)PAu-AuPPh(3)]-capped ligands along with 4 PR(3) and 10 CO ligands, to be remarkably similar to that of the previously reported Pt(17)(mu(2)-CO)(4)(CO)(8)(PEt(3))(8) (2). Reformulation of 2 as Pt(13)[(PtPEt(3))(2)(mu(2)-CO)](2)(CO)(10)(PEt(3))(4) emphasizes the steric/electronic resemblance of the bulky-sized bidentate [Ph(3)PAu-AuPPh(3)] and [(PtPEt(3))(2)(mu(2)-CO)] capping ligands in 1 and 2, respectively, as well as their identical electron counts of 162 cluster valence electrons for a centered Pt(13) icosahedron. We hypothesize that analogous steric effects of their ligand polyhedra in 1 and 2 play a crucial role along with electronic effects in the formation and stabilization of these two nanosized clusters that contain an otherwise unknown centered icosahedron of platinum atoms. PMID:16363819

  8. 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

  9. Chemoselective ligation

    DOEpatents

    Saxon, Eliana (Albany, CA); Bertozzi, Carolyn R. (Berkeley, CA)

    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).

  10. Chemoselective ligation

    DOEpatents

    Saxon, Eliana (Albany, CA); Bertozzi, Carolyn R. (Berkeley, CA)

    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).

  11. Chemoselective ligation

    DOEpatents

    Saxon, Eliana (Albany, CA); Bertozzi, Carolyn Ruth (Berkeley, CA)

    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).

  12. Chemoselective ligation

    DOEpatents

    Saxon, Eliana (Albany, CA); Bertozzi, Carolyn R. (Berkeley, CA)

    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).

  13. 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).

  14. Chemoselective ligation

    DOEpatents

    Saxon, Eliana (Albany, CA); Bertozzi, Carolyn (Berkeley, CA)

    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).

  15. Chemoselective ligation

    DOEpatents

    Saxon, Eliana (Albany, CA); Bertozzi, Carolyn Ruth (Berkeley, CA)

    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).

  16. A novel approach to catalytic desulfurization of coal. Semi-annual report

    SciTech Connect

    Verkade, J.G.

    1997-07-01

    A gas chromatographic method has been developed for the quantitation of sulfur removed from coal as tributyl phosphine sulfide. The method also works well for quantitating the products of sulfur removed compounds such as dibenzothiophene.

  17. 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

  18. 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.

  19. 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.

  20. Minimizing Aryloxy Elimination in Rh(I) -Catalyzed Asymmetric Hydrogenation of ?-Aryloxyacrylic Acids using a Mixed-Ligand Strategy.

    PubMed

    Li, Yang; Wang, Zheng; Ding, Kuiling

    2015-11-01

    The first example of efficient asymmetric hydrogenation of challenging ?-aryloxyacrylic acids was realized using a Rh(I) -complex based on the heterocombination of a readily available chiral monodentate secondary phosphine oxide (SPO) and an achiral monodentate phosphine ligand as the catalyst. Excellent enantioselectivities (92->99?% ee) were achieved for a wide variety of chiral ?-aryloxypropionic acids with minor aryloxy elimination in most cases. The resultant products were readily transformed into biologically active compounds through simple synthetic manipulations. PMID:26424205

  1. 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.

  2. Facilitated carbon dioxide reduction using a Zn(ii) complex.

    PubMed

    Donovan, Elizabeth S; Barry, Brian M; Larsen, Christopher A; Wirtz, Melissa N; Geiger, William E; Kemp, Richard A

    2016-01-28

    Two new Zn(ii) complexes have been prepared and evaluated for their capacity to activate and reduce CO2. The electrochemical properties of dichloro[phenyldi(2-pyridyl)phosphine-?(2)-N,N']zinc(ii) 1 and dichloro[diphenyl-(2-pyridyl)phosphine-?(1)-N]zinc(ii) 2 are compared using cyclic voltammetry. Electrochemical results indicate that 2 leads to a facilitated CO2 reduction to evolve CO at a glassy carbon electrode. PMID:26660087

  3. Methods for suppressing isomerization of olefin metathesis products

    DOEpatents

    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.

  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. Ortho-phosphinobenzenesulfonate: a superb ligand for palladium-catalyzed coordination-insertion copolymerization of polar vinyl monomers.

    PubMed

    Nakamura, Akifumi; Anselment, Timo M J; Claverie, Jerome; Goodall, Brian; Jordan, Richard F; Mecking, Stefan; Rieger, Bernhard; Sen, Ayusman; van Leeuwen, Piet W N M; Nozaki, Kyoko

    2013-07-16

    Ligands, Lewis bases that coordinate to the metal center in a complex, can completely change the catalytic behavior of the metal center. In this Account, we summarize new reactions enabled by a single class of ligands, phosphine-sulfonates (ortho-phosphinobenzenesulfonates). Using their palladium complexes, we have developed four unusual reactions, and three of these have produced novel types of polymers. In one case, we have produced linear high-molecular weight polyethylene, a type of polymer that group 10 metal catalysts do not typically produce. Secondly, complexes using these ligands catalyzed the formation of linear poly(ethylene-co-polar vinyl monomers). Before the use of phosphine-sulfonate catalysts, researchers could only produce ethylene/polar monomer copolymers that have different branched structures rather than linear ones, depending on whether the polymers were produced by a radical polymerization or a group 10 metal catalyzed coordination polymerization. Thirdly, these phosphine-sulfonate catalysts produced nonalternating linear poly(ethylene-co-carbon monoxide). Radical polymerization gives ethylene-rich branched ethylene/CO copolymers copolymers. Prior to the use of phosphine-sulfonates, all of the metal catalyzed processes gave completely alternating ethylene/carbon monoxide copolymers. Finally, we produced poly(polar vinyl monomer-alt-carbon monoxide), a copolymerization of common polar monomers with carbon monoxide that had not been previously reported. Although researchers have often used symmetrical bidentate ligands such as diimines for the polymerization catalysis, phosphine-sulfonates are unsymmetrical, containing two nonequivalent donor units, a neutral phosphine, and an anionic sulfonate. We discuss the features that make this ligand unique. In order to understand all of the new reactions facilitated by this special ligand, we discuss both the steric effect of the bulky phosphines and electronic effects. We provide a unified interpretation of the unique reactivity by considering of the net charge and the enhanced back donation in the phosphine-sulfonate complexes. PMID:23544427

  6. Catalyst-Switchable Regiocontrol in the Direct Arylation of Remote CH Groups in Pyrazolo[1,5-a]pyrimidines**

    PubMed Central

    Bedford, Robin B; Durrant, Steven J; Montgomery, Michelle

    2015-01-01

    The regiodivergent palladium-catalyzed CH 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

  7. 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.

  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. Reaction of bis(phosphine)(hydrotris(3,5-dimethylpyrazolyl)borato)rhodium(I) with phenylacetylene, p-nitrobenzaldehyde, and triphenyltin hydride: structures of [Rh(Tp)(PPh(3))(2)], [Rh(Tp)(H)(C(2)Ph)(P(4-C(6)H(4)F)(3))], [Rh(Tp)(H)(COC(6)H(4)-4-NO(2))(PPh(3))], and [Rh(Tp)(H)(SnPh(3))(PPh(3))].

    PubMed

    Crcu, Viorel; Fernandes, Manuel A; Carlton, Laurence

    2002-07-29

    The complexes [Rh(Tp)(PPh(3))(2)] (1a) and [Rh(Tp)(P(4-C(6)H(4)F)(3))(2)] (1b) combine with PhC(2)H, 4-NO(2)-C(6)H(4)CHO and Ph(3)SnH to give [Rh(Tp)(H)(C(2)Ph)(PR(3))] (R = Ph, 2a; R = 4-C(6)H(4)F, 2b), [Rh(Tp)(H)(COC(6)H(4)-4-NO(2))(PR(3))] (R = Ph, 3a), and [Rh(Tp)(H)(SnPh(3))(PR(3))] (R = Ph, 4a; R = 4-C(6)H(4)F, 4b) in moderate to good yield. Complexes 1a, 2b, 3a, and 4a have been structurally characterized. In 1a the Tp ligand is bidentate, in 2b, 3a, and 4a it is tridentate. Crystal data for 1a: space group P2(1)/c; a = 11.9664(19), b = 21.355(3), c = 20.685(3) A; beta = 112.576(7) degrees; V = 4880.8(12) A(3); Z = 4; R = 0.0441. Data for 2b: space group P(-)1; a = 10.130(3), b = 12.869(4), c = 17.038(5) A; alpha = 78.641(6), beta = 76.040(5), gamma = 81.210(6) degrees; V = 2100.3(11) A(3); Z = 2; R = 0.0493. Data for 3a: space group P(-)1; a = 10.0073(11), b = 10.5116(12), c = 19.874(2) A; alpha = 83.728(2), beta = 88.759(2), gamma = 65.756(2) degrees; V =1894.2(4) A(3); Z = 2; R = 0.0253. Data for 4a: space group P2(1)/c; a = 15.545(2), b = 18.110(2), c = 17.810(2) A; beta = 95.094(3) degrees; V = 4994.1(10) A(3); Z = 4; R = 0.0256. NMR data ((1)H, (31)P, (103)Rh, (119)Sn) are also reported. PMID:12132909

  10. 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.

  11. 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}

  12. Method for separating metal chelates from other materials based on solubilities in supercritical fluids

    DOEpatents

    Wai, Chien M. (Moscow, ID); Smart, Neil G. (Workington, GB); Phelps, Cindy (Moscow, ID)

    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.

  13. A Strategy to Control the Reactivation of Frustrated Lewis Pairs from Shelf-Stable Carbene Borane Complexes

    PubMed Central

    Hoshimoto, Yoichi; Kinoshita, Takuya; Ohashi, Masato; Ogoshi, Sensuke

    2015-01-01

    N-Phosphine oxide substituted imidazolylidenes (PoxIms) have been synthesized and fully characterized. These species can undergo significant changes to the spatial environment surrounding their carbene center through rotation of the phosphine oxide moiety. Either classical Lewis adducts (CLAs) or frustrated Lewis pairs (FLPs) are thus formed with B(C6F5)3 depending on the orientation of the phosphine oxide group. A strategy to reactivate FLPs from CLAs by exploiting molecular motions that are responsive to external stimuli has therefore been developed. The reactivation conditions were successfully controlled by tuning the strain in the PoxImB(C6F5)3 complexes so that reactivation only occurred above ambient temperature. PMID:26315680

  14. A computational study on the insertion of CO2 into (PSiP)palladium allyl ?-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

  15. 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.

  16. 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.

  17. Heterogeneous catalyst for the production of acetic anhydride from methyl acetate

    DOEpatents

    Ramprasad, Dorai (Allentown, PA); Waller, Francis Joseph (Allentown, PA)

    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.

  18. [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

  19. 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.

  20. Parahydrogen Induced Polarization with Rh-based Monodentate Ligand in Water

    PubMed Central

    Shchepin, Roman V.; Coffey, Aaron M.; Waddell, Kevin W.; Chekmenev, Eduard Y.

    2012-01-01

    Reported here is a water soluble Rh(I)-based catalyst for performing parahydrogen induced polarization (PHIP). The [Rh(I)(norbornadiene)(THP)2]+[BF4]- catalyst utilizes the monodentate phosphine ligand tris(hydroxymethyl)phosphine (THP). The monodentate PHIP catalyst is less susceptible to oxygenation by air and THP ligand and is significantly less expensive than bidentate water-soluble PHIP ligands. In situ PHIP detection with this monodentate Rh(I) based catalyst in water yielded 12% 13C polarization for the parahydrogen addition product, 2-hydroxyethyl 1-13C-propionate-d2,3,3 (HEP), with a 13C T1 relaxation of 108 seconds at 0.0475 T. PHIP polarization yields were high, reflecting efficient hydrogenation even under conditions of high content of the oxidized phosphine form of the THP ligand. PMID:23227297