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Sample records for phosphines

  1. Phosphine

    Integrated Risk Information System (IRIS)

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

  2. Microbially mediated phosphine emission.

    PubMed

    Roels, Joris; Huyghe, Gwen; Verstraete, Willy

    2005-02-15

    There is still a lot of controversy in literature concerning the question whether a biochemical system exists enabling micro-organisms to reduce phosphate to phosphine gas. The search for so-called 'de novo synthesised' phosphine is complicated by the fact that soils, slurries, sludges, etc., which are often used as inocula, usually contain matrix bound phosphine (MBP). Matrix bound phosphine is a general term used to indicate non-gaseous reduced phosphorus compounds that are transformed into phosphine gas upon reaction with bases or acids. A study was carried out to compare the different digestion methods, used to transform matrix bound phosphine into phosphine gas. It was demonstrated that caustic and acidic digestion methods should be used to measure the matrix bound phosphine of the inoculum prior to inoculation to avoid false positive results concerning de novo synthesis. This is especially true if anthropogenically influenced inocula possibly containing minute steel or aluminium particles are used. The comparative study on different digestion methods also revealed that the fraction of phosphorus in mild steel, converted to phosphine during acid corrosion depended on the temperature. Following these preliminary studies, anaerobic growth experiments were set up using different inocula and media to study the emission of phosphine gas. Phosphine was detected in the headspace gases and its quantity and timeframe of emission depended on the medium composition, suggesting microbially mediated formation of the gas. The amount of phosphine emitted during the growth experiments never exceeded the bound phosphine present in inocula, prior to inoculation. Hence, de novo synthesis of phosphine from phosphate could not be demonstrated. Yet, microbially mediated conversion to phosphine of hitherto unknown reduced phosphorus compounds in the inoculum was evidenced. PMID:15713333

  3. 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.

  4. 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 (C(n)DMPO) and alkyl diethyl (C(n)DEPO) 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

  5. Phosphine Catalysis of Allenes with Electrophiles

    PubMed Central

    Wang, Zhiming; Xu, Xingzhu; Kwon, Ohyun

    2014-01-01

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

  6. Catalytic Asymmetric Synthesis of Phosphine Boronates.

    PubMed

    Hornillos, Valentín; Vila, Carlos; Otten, Edwin; Feringa, Ben L

    2015-06-26

    The first catalytic enantioselective synthesis of ambiphilic phosphine boronate esters is presented. The asymmetric boration of α,β-unsaturated phosphine oxides catalyzed by a copper bisphosphine complex affords optically active organoboronate esters that bear a vicinal phosphine oxide group in good yields and high enantiomeric excess. The synthetic utility of the products is demonstrated through stereospecific transformations into multifunctional optically active compounds. PMID:25950871

  7. 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.

  8. 40 CFR 721.10087 - Substituted alkyl phosphine oxide (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Substituted alkyl phosphine oxide... Specific Chemical Substances § 721.10087 Substituted alkyl phosphine oxide (generic). (a) Chemical... as substituted alkyl phosphine oxide (PMN P-06-332) is subject to reporting under this section...

  9. 40 CFR 721.10087 - Substituted alkyl phosphine oxide (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Substituted alkyl phosphine oxide... Specific Chemical Substances § 721.10087 Substituted alkyl phosphine oxide (generic). (a) Chemical... as substituted alkyl phosphine oxide (PMN P-06-332) is subject to reporting under this section...

  10. 40 CFR 721.10087 - Substituted alkyl phosphine oxide (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Substituted alkyl phosphine oxide... Specific Chemical Substances § 721.10087 Substituted alkyl phosphine oxide (generic). (a) Chemical... as substituted alkyl phosphine oxide (PMN P-06-332) is subject to reporting under this section...

  11. 40 CFR 721.10087 - Substituted alkyl phosphine oxide (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Substituted alkyl phosphine oxide... Specific Chemical Substances § 721.10087 Substituted alkyl phosphine oxide (generic). (a) Chemical... as substituted alkyl phosphine oxide (PMN P-06-332) is subject to reporting under this section...

  12. 40 CFR 721.10087 - Substituted alkyl phosphine oxide (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Substituted alkyl phosphine oxide... Specific Chemical Substances § 721.10087 Substituted alkyl phosphine oxide (generic). (a) Chemical... as substituted alkyl phosphine oxide (PMN P-06-332) is subject to reporting under this section...

  13. Reactions of two-coordinate phosphines with acetylenes: Synthesis of new allenic and acetylenic phosphines

    SciTech Connect

    Angelov, C.M.; Neilson, R.H. )

    1993-02-03

    The two-coordinate phosphines (Me[sub 3]Si)[sub 2]NP[double bond]ESiMe[sub 3] (1, E = N; 2, E = CH) reacted smoothly with 2-butyne via an ene process (instead of the expected cycloaddition reaction) to give the novel allenic phosphines H[sub 2]C[double bond]C[double bond]C(CH[sub 3])P[E(H)SiMe[sub 3

  14. 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.

  15. Cationic ruthenium alkylidene catalysts bearing phosphine ligands.

    PubMed

    Endo, Koji; Grubbs, Robert H

    2016-02-28

    The discovery of highly active catalysts and the success of ionic liquid immobilized systems have accelerated attention to a new class of cationic metathesis catalysts. We herein report the facile syntheses of cationic ruthenium catalysts bearing bulky phosphine ligands. Simple ligand exchange using silver(i) salts of non-coordinating or weakly coordinating anions provided either PPh3 or chelating Ph2P(CH2)nPPh2 (n = 2 or 3) ligated cationic catalysts. The structures of these newly reported catalysts feature unique geometries caused by ligation of the bulky phosphine ligands. Their activities and selectivities in standard metathesis reactions were also investigated. These cationic ruthenium alkylidene catalysts reported here showed moderate activity and very similar stereoselectivity when compared to the second generation ruthenium dichloride catalyst in ring-closing metathesis, cross metathesis, and ring-opening metathesis polymerization assays.

  16. Enantioselective Cu-Catalyzed Arylation of Secondary Phosphine Oxides with Diaryliodonium Salts toward the Synthesis of P-Chiral Phosphines

    PubMed Central

    2016-01-01

    Catalytic synthesis of nonracemic P-chiral phosphine derivatives remains a significant challenge. Here we report Cu-catalyzed enantioselective arylation of secondary phosphine oxides with diaryliodonium salts for the synthesis of tertiary phosphine oxides with high enantiomeric excess. The new process is demonstrated on a wide range of substrates and leads to products that are well-established P-chiral catalysts and ligands. PMID:27689432

  17. Perfluoropropenyl-containing phosphines from HFC replacements.

    PubMed

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

    2015-12-01

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

  18. 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...

  19. 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

  20. Simple spectrophotometric method for determination of phosphine residues in wheat.

    PubMed

    Rangaswamy, J R

    1984-01-01

    A method has been developed for determination of phosphine residues in wheat, based on the reaction of phosphine with silver nitrate in aqueous solution to form an egg-yellow chromophore with an absorption maximum at 400 nm. At this wavelength, there is a linear relationship between absorbance and concentration of phosphine in the range 10-100 ng/mL. Phosphine-fumigated wheat is soaked in a known volume of AgNO3 solution, and the absorbance of the filtrate is read against a blank at 400 nm. The method is sensitive, with lower detection and estimation limits of 0.008 and 0.01 micrograms PH3, respectively. Recovery of added phosphine from a closed system was 85-100%. Accuracy for this method has been compared with that for the gas chromatographic method.

  1. Communication: Tunnelling splitting in the phosphine molecule

    NASA Astrophysics Data System (ADS)

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

    2016-09-01

    Splitting due to tunnelling via the potential energy barrier has played a significant role in the study of molecular spectra since the early days of spectroscopy. The observation of the ammonia doublet led to attempts to find a phosphine analogous, but these have so far failed due to its considerably higher barrier. Full dimensional, variational nuclear motion calculations are used to predict splittings as a function of excitation energy. Simulated spectra suggest that such splittings should be observable in the near infrared via overtones of the ν2 bending mode starting with 4ν2.

  2. Communication: Tunnelling splitting in the phosphine molecule.

    PubMed

    Sousa-Silva, Clara; Tennyson, Jonathan; Yurchenko, Sergey N

    2016-09-01

    Splitting due to tunnelling via the potential energy barrier has played a significant role in the study of molecular spectra since the early days of spectroscopy. The observation of the ammonia doublet led to attempts to find a phosphine analogous, but these have so far failed due to its considerably higher barrier. Full dimensional, variational nuclear motion calculations are used to predict splittings as a function of excitation energy. Simulated spectra suggest that such splittings should be observable in the near infrared via overtones of the ν2 bending mode starting with 4ν2. PMID:27608982

  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. Oxidative alkoxylation of phosphine in alcohol solutions of copper halides

    NASA Astrophysics Data System (ADS)

    Polimbetova, G. S.; Borangazieva, A. K.; Ibraimova, Zh. U.; Bugubaeva, G. O.; Keynbay, S.

    2016-08-01

    The phosphine oxidation reaction with oxygen in alcohol solutions of copper (I, II) halides is studied. Kinetic parameters, intermediates, and by-products are studied by means of NMR 31Р-, IR-, UV-, and ESR- spectroscopy; and by magnetic susceptibility, redox potentiometry, gas chromatography, and elemental analysis. A reaction mechanism is proposed, and the optimum conditions are found for the reaction of oxidative alkoxylation phosphine.

  5. Oxidative alkoxylation of phosphine in alcohol solutions of copper halides

    NASA Astrophysics Data System (ADS)

    Polimbetova, G. S.; Borangazieva, A. K.; Ibraimova, Zh. U.; Bugubaeva, G. O.; Keynbay, S.

    2016-08-01

    The phosphine oxidation reaction with oxygen in alcohol solutions of copper (I, II) halides is studied. Kinetic parameters, intermediates, and by-products are studied by means of NMR 31P-, IR-, UV-, and ESR- spectroscopy; and by magnetic susceptibility, redox potentiometry, gas chromatography, and elemental analysis. A reaction mechanism is proposed, and the optimum conditions are found for the reaction of oxidative alkoxylation phosphine.

  6. Responses of Phosphate Transporter Gene and Alkaline Phosphatase in Thalassiosira pseudonana to Phosphine

    PubMed Central

    Fu, Mei; Song, Xiuxian; Yu, Zhiming; Liu, Yun

    2013-01-01

    Phosphine, which is released continuously from sediment, can affect the eco-physiological strategies and molecular responses of phytoplankton. To examine the effects of phosphine on phosphorus uptake and utilization in Thalassiosira pseudonana, we examined the transcriptional level of the phosphate transporter gene (TpPHO) and the activity of alkaline phosphatase (AKP) in relation to supplement of various concentrations of phosphine. TpPHO expression was markedly promoted by phosphine in both the phosphate-deficient and phosphate-4 µM culture. However, high phosphine concentrations can inhibit TpPHO transcription in the declining growth phase. AKP activity was also higher in the phosphine treatment groups than that of the control. It increased with increasing phosphine concentration in the range of 0 to 0.056 µM but was inhibited by higher levels of phosphine. These responses revealed that phosphine can affect phosphate uptake and utilization in T. pseudonana. This result was consistent with the effect of phosphine on algal growth, while TpPHO expression and AKP were even more sensitive to phosphine than algal growth. This work provides a basic understanding for further research about how phosphine affects phytoplankton. PMID:23544096

  7. Genes related to mitochondrial functions 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-...

  8. 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

  9. Alkylation of H-Phosphinate Esters under Basic Conditions

    PubMed Central

    Abrunhosa-Thomas, Isabelle; Sellers, Claire E.; Montchamp, Jean-Luc

    2008-01-01

    An efficient and general procedure was developed for the direct alkylation of H-phosphinate esters with LiHMDS at low temperature. The simplicity of the reaction allows the use of various H-phosphinate esters and takes place with a wide range of electrophiles. The approach can be employed to access some GABA analogs or precursors to GABA analogs. The isolated yields are moderate to good. This is the first report of an alkylation with a secondary iodide, or a primary chloride. PMID:17352490

  10. A superior method for the reduction of secondary phosphine oxides.

    PubMed

    Busacca, Carl A; Lorenz, Jon C; Grinberg, Nelu; Haddad, Nizar; Hrapchak, Matt; Latli, Bachir; Lee, Heewon; Sabila, Paul; Saha, Anjan; Sarvestani, Max; Shen, Sherry; Varsolona, Richard; Wei, Xudong; Senanayake, Chris H

    2005-09-15

    [reaction: see text] Diisobutylaluminum hydride (DIBAL-H) and triisobutylaluminum have been found to be outstanding reductants for secondary phosphine oxides (SPOs). All classes of SPOs can be readily reduced, including diaryl, arylalkyl, and dialkyl members. Many SPOs can now be reduced at cryogenic temperatures, and conditions for preservation of reducible functional groups have been found. Even the most electron-rich and sterically hindered phosphine oxides can be reduced in a few hours at 50-70 degrees C. This new reduction has distinct advantages over existing technologies. PMID:16146406

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

    NASA Astrophysics Data System (ADS)

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

    2016-06-01

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

  12. Synthesis of Functionalized Furans via Chemoselective Reduction/Wittig Reaction Using Catalytic Triethylamine and Phosphine.

    PubMed

    Lee, Chia-Jui; Chang, Tzu-Hsiu; Yu, Jhen-Kuei; Madhusudhan Reddy, Ganapuram; Hsiao, Ming-Yu; Lin, Wenwei

    2016-08-01

    An efficient protocol for the synthesis of highly functionalized furans via intramolecular Wittig reaction has been developed using catalytic amounts of phosphine and triethylamine. Silyl chloride served as the initial promoter to activate the phosphine oxide. Reduction of the activated phosphine oxide by hydrosilane resulted in generation of phosphine, while decomposition of Et3N·HCl resulted in regeneration of base, which mediated formation of phosphorus ylide. Remarkably, the in situ generated byproduct, Et3N·HCl, also catalyzes reduction of phosphine oxide. PMID:27434727

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

    PubMed

    Liu, Yong-Biao

    2012-06-01

    Low temperature regular phosphine fumigations under the normal oxygen level and oxygenated phosphine fumigations under superatmospheric oxygen levels were compared for efficacy against the aphid, Nasonovia ribisnigri (Mosley), and effects on postharvest quality of romaine and head lettuce. Low temperature regular phosphine fumigation was effective against the aphid. However, a 3 d treatment with high phosphine concentrations of > or = 2,000 ppm was needed for complete control of the aphid. Oxygen greatly increased phosphine toxicity and significantly reduced both treatment time and phosphine concentration for control of N. ribisnigri. At 1,000 ppm phosphine, 72 h regular fumigations at 6 degrees C did not achieve 100% mortality of the aphid. The 1,000 ppm phosphine fumigation under 60% O2 killed all aphids in 30 h. Both a 72 h regular fumigation with 2,200 ppm phosphine and a 48 h oxygenated fumigation with 1,000 ppm phosphine under 60% O2 were tested on romaine and head lettuce at 3 degrees C. Both treatments achieved complete control of N. ribisnigri. However, the 72 h regular fumigation resulted in significantly higher percentages of lettuce with injuries and significantly lower lettuce internal quality scores than the 48 h oxygenated phosphine fumigation. Although the oxygenated phosphine fumigation also caused injuries to some treated lettuce, lettuce quality remained very good and the treatment is not expected to have a significant impact on marketability of the lettuce. This study demonstrated that oxygenated phosphine fumigation was more effective and less phytotoxic for controlling N. ribisnigri on harvested lettuce than regular phosphine fumigation and is promising for practical use. PMID:22812116

  14. Synthesis, Structure, and Applications of α-Cationic Phosphines.

    PubMed

    Alcarazo, Manuel

    2016-09-20

    In α-cationic phosphines, at least one of the three substituents on phosphorus corresponds to a cationic (normally, but not always heteroaromatic) group, which is attached without any spacer to the phosphorus atom by a relatively inert P-C bond. This unique architecture confers to the resulting ligand strong acceptor properties, which frequently surpass those of traditional acceptor ligands such as phosphites or polyfluorinated phosphines. In addition, the fine-tuning of the stereoelectronic properties of α-cationic phosphines is also possible by judicious selection of the number and nature of the cationic groups. The opportunities offered in catalysis by α-cationic ligands arise from this ability to deplete electron density from the metals they coordinate. Thus, if in a hypothetical catalytic cycle the step that determines the rate is facilitated by an increase of the Lewis acidity at the metal center, then an acceleration of the whole process is expected by their use as ancillary ligands. Interestingly, this situation is found more frequently than one might think; many common elementary steps involved in catalytic cycles, such as reductive eliminations, coordination of substrates to metals, or attack of nucleophiles to coordinated substrates, belong to this category and are often fostered by electron poor metal centers. In this regard, our group has observed remarkable ligand acceleration effects by the employment of α-cationic phosphines in Au(I)- and Pt(II)-promoted hydroarylation and cycloisomerization reactions. These results seem to be general in π-acid catalysis when the nucleophile used is not especially electron rich because then their attack to the activated alkene or alkyne is normally rate determining. On the other hand, the use of cationic phosphines also presents drawbacks that limit their range of application. As a general rule, the reduced σ-donation from the phosphine is not compensated by the increased π-back-donation from the metal making

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

    PubMed Central

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

    2015-01-01

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

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

    PubMed

    Copey, Laurent; Jean-Gérard, 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.

  17. 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

  18. Toward the formation of alkylphosphonic acids in phosphine ices

    NASA Astrophysics Data System (ADS)

    Turner, Andrew; Kaiser, Ralf-Ingo

    2016-10-01

    Phosphorus is one of the elemental building blocks of life on Earth and is important for information storage (RNA/DNA), energy transfer (ATP), cell membranes (phospholipids), and structure (bones & teeth). Due to the poor bioavailability of highly oxidized phosphorus (P(V)) found in ubiquitous phosphate (PO43-) minerals, reduced oxidation state (P(III)) compounds have been proposed as a phosphorus source for early life on Earth. Among these, the alkylphosphonic acids, which are the only phosphorus-containing organic compounds discovered in the Murchison meteorite, are a suggested exogenous source of prebiotic phosphorus. Phosphine (PH3) is a known component of the atmospheres of Jupiter and Saturn, and the confirmation of circumstellar phosphine in the carbon-rich envelop of IRC +10216 along with the recent detection of phosphorus in the comet 67P/Churyumov-Gerasimenko provide an additional foundation for studying extraterrestrial phosphorus chemistry and the origins of the alkylphosphonic acids. In the present study, reactions of phosphine ices with water (H2O), carbon dioxide (CO2), and methane (CH4) were investigated using Fourier transform infrared spectroscopy (FTIR), quadrupole mass spectrometry (QMS), and most notably, reflectron time-of-flight mass spectrometry using tunable photoionization (PI-ReTOF-MS). Experiments were conducted at ultra-high vacuum pressures and cryogenic temperatures to better understand reaction pathways and products of phosphorus-containing compounds under icy conditions found in comets or the interstellar medium. The results of this study can provide support to the hypothesis that the alkylphosphonic acids were formed from interstellar phosphine and incorporated into meteorites such as Murchison.

  19. Nitratotris(triphenyl­phosphine)copper(I) methanol solvate

    PubMed Central

    Steyl, Gideon

    2009-01-01

    The title compound, [Cu(NO3)(C18H15P)3]·CH3OH, is a methanol solvate derivative of nitratotris(triphenyl­phos­phine)copper(I). The complex crystallizes with three triphenyl­phosphine ligands coordinated to the copper centre, with an O—H⋯O hydrogen bond observed between the nitrate ligand and the methanol solvent mol­ecule. The coordination around the CuI centre is distorted tetrahedral. PMID:21582060

  20. 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.

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

    PubMed

    Achard, Thierry

    2016-01-01

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

  2. The response of phosphine-resistant lesser grain borer Rhyzopertha dominica and rice weevil Sitophilus oryzae in mixed-age cultures to varying concentrations of phosphine.

    PubMed

    Rajendran, Somiahnadar; Gunasekaran, Nagamuthu

    2002-03-01

    The response of Rhyzopertha dominica and Sitophilus oryzae (both phosphine-resistant) in mixed-age cultures to phosphine at fixed concentration-time products (CT) of 10,500 to 168,000 microliters litre 1 h (ppm h) with either constant, rising or falling concentrations for 7 days was studied at 27 (+/- 2) degrees C. At lower CT products, rising concentrations of phosphine led to significantly fewer survivors of R dominica and S oryzae. Conversely, exposure to falling concentrations of phosphine resulted in significantly more survivors. The influence of changing concentrations of phosphine was more pronounced in S oryzae than in R dominica. In the latter, at the lower CT products of 21,000 and 42,000 microliters-1 h, the adult stage proved to be most tolerant, contrary to the accepted belief that the egg or pupal stage are always more tolerant to phosphine. The results indicate that application of phosphine in rising concentrations is more effective than in constant or falling concentrations.

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

    ERIC Educational Resources Information Center

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

    2007-01-01

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

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

    PubMed

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

    2016-02-01

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

  5. Palladium-catalyzed dehydrogenative coupling of terminal alkynes with secondary phosphine oxides.

    PubMed

    Yang, Jia; Chen, Tieqiao; Zhou, Yongbo; Yin, Shuangfeng; Han, Li-Biao

    2015-02-28

    The dehydrogenative coupling of terminal alkynes with secondary phosphine oxides is developed. In the presence of a silver additive, palladium acetate could efficiently catalyze the dehydrocoupling of secondary phosphine oxides with a variety of terminal alkynes to produce the corresponding alkynylphosphine oxides in high yields. A reaction mechanism is proposed. PMID:25627893

  6. 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.

  7. Isocyanide and Phosphine Oxide Coordination in Binuclear Chromium Pacman Complexes.

    PubMed

    Stevens, Charlotte J; Nichol, Gary S; Arnold, Polly L; Love, Jason B

    2013-12-01

    The new binuclear chromium Pacman complex [Cr2(L)] of the Schiff base pyrrole macrocycle H4L has been synthesized and structurally characterized. Addition of isocyanide, C≡NR (R = xylyl, (t)Bu), or triphenylphosphine oxide donors to [Cr2(L)] gives contrasting chemistry with the formation of the new coordination compounds [Cr2(μ-CNR)(L)], in which the isocyanides bridge the two Cr(II) centers, and [Cr2(OPPh3)2(L)], a Cr(II) phosphine oxide adduct with the ligands exogenous to the cleft.

  8. Spectrophotometric method for determination of phosphine residues in cashew kernels.

    PubMed

    Rangaswamy, J R

    1988-01-01

    A spectrophotometric method reported for determination of phosphine (PH3) residues in wheat has been extended for determination of these residues in cashew kernels. Unlike the spectrum for wheat, the spectrum of PH3 residue-AgNO3 chromophore from cashew kernels does not show an absorption maximum at 400 nm; nevertheless, reading the absorbance at 400 nm afforded good recoveries of 90-98%. No interference occurred from crop materials, and crop controls showed low absorbance; the method can be applied for determinations as low as 0.01 ppm PH3 residue in cashew kernels.

  9. 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 P–C, P–N, and P–O 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

  10. 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.

  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. Oxygenated phosphine fumigation for control of Epiphyas postvittana (Lepidoptera: Tortricidae) eggs on lettuce.

    PubMed

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

    2014-08-01

    Light brown apple moth, Epiphyas postvittana (Walker), is a quarantined pest in most countries. Its establishment in California and potential spread to other parts of the state and beyond make it urgent to develop effective postharvest treatments to control the pest on fresh commodities. Fumigation with cylindered phosphine at low temperature has emerged to be a practical methyl bromide alternative treatment for postharvest pest control on fresh commodities. However, its use to control E. postvittana eggs on sensitive commodities such as lettuce is problematic. E. postvittana eggs are tolerant of phosphine and long phosphine treatment also injures lettuce. In the current study, E. postvittana eggs were subjected to oxygenated phosphine fumigations to develop an effective treatment at a low storage temperature of 2 degrees C. In addition, soda lime as a CO2 absorbent was tested to determine its effects in reducing and preventing injuries to lettuce associated with phosphine fumigations. Three-day fumigation with 1,000 ppm phosphine under 60% O2 achieved 100% mortality of E. postvittana eggs in small-scale laboratory tests. In the presence of the CO2 absorbent, a 3-d large-scale fumigation of lettuce with 1,700 ppm phosphine under 60% O2 resulted in a relative egg mortality of 99.96% without any negative effect on lettuce quality. The 3-d fumigation treatment without the CO2 absorbent, however, resulted in significant injuries to lettuce and consequential quality reductions. The study demonstrated that oxygenated phosphine fumigation has the potential to control E. postvittana eggs and the CO2 absorbent has the potential to prevent injuries and quality reductions of lettuce associated with long-term oxygenated phosphine fumigation.

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

    SciTech Connect

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

    2002-10-01

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

  14. 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.

  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).

    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

  17. 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.

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

    DOEpatents

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

    2000-01-01

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

  19. 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. 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...

  1. 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...

  2. 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...

  3. 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...

  4. 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...

  5. [Determination of phosphine liberated in the storage of amorphous red phosphorus by headspace gas chromatography].

    PubMed

    Chen, Haiqun; Zhou, Yahong; Zhu, Junwu; Yang, Xujie; Lu, Lude; Wang, Xin

    2004-07-01

    Formation and liberation of phosphine has been an important factor and concern in the safety of the storage of amorphous red phosphorous. A method was established for the analysis of phosphine, which was determined by gas chromatography with a flame photometric detector and a column of 3 mm i. d. x 2 m glass tube packed with GDX-102 stationary phase. An aliquot of 0.2 mL of the gas was injected by headspace sampler for the determination of the target compound with external standard quantitation. The retention time of phosphine was 1.62 min at 50 degrees C. The minimum detectable amount was 0.001 microg/L, the recovery exceeded 97% and the relative standard deviations were from 2.35% to 6.52%. The accelerated ageing tests at 50 degrees C were used to study phosphine liberation from amorphous red phosphorus in presence of trace water and trace ferric cation. It was found that water was the most important agent in the generation of phosphine as it was the source of hydrogen for the reaction P --> PH3. With the increase of the moisture level in the red phosphorus sample, the reaction speeded up more quickly, and the generation amount of phosphine increased, but the phosphine liberation increased little when the level of moisture reached a certain limit. The reaction was affected by a trace amount of ferric salt. Different acidic ferric salts showed different results. Potassium ferrocyanide was found as an effective inhibitor to slow down phosphine liberation in the presence of trace ferric salt. PMID:15709430

  6. 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 (μ-pdt)Fe2(CO)6 or (μ-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.

  7. 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 CO(2) levels were also investigated, and we found that a CO(2) concentration between 10% and 15% under CA conditions was optimal for low-temperature phosphine fumigation. PMID:26470302

  8. Chemical reactivity of labile sulfur of iron-sulfur proteins. The reaction of triphenyl phosphine.

    PubMed

    Manabe, T; Goda, K; Kimura, T

    1976-04-23

    The reaction of triphenyl phosphine to iron-sulfur proteins from adrenal cortex mitochondria, spinach chloroplasts, and Clostridium pasteurianum was investigated. As ethanol concentrations in the reaction mixture increased, the rate of the reaction decreased. In the simultaneous presence of 1 M KC1 and 5 M urea, the reaction rate reached at maximum. Under these conditions the initial rates of the decolorization reaction by the phosphine were found to be 8.7, 0.88, and 1.8 nmol of ferredoxin per min at 25 degrees C for adrenal, spinach, and clostridial ferredoxins, respectively. The kinetic curves for the reaction of the phosphine sulfide formation, the loss of labile sulfur, and the deterioriation of visible absorption showed a similar pattern with a comparable rate. During this reaction, the complete reduction of ferric ions present in ferredoxin was observed with a fast rate under either aerobic or anaerobic conditions. These results suggest that the iron atoms in ferredoxin are first reduced by the intramolecular reductants in the presence of triphenyl phosphine with the concomitant formation of S2-2, which then reacts with triphenyl phosphine resulting in the formation of triphenyl phosphine sulfide.

  9. A novel tridentate bis(phosphinic acid)phosphine oxide based europium(III)-selective Nafion membrane luminescent sensor.

    PubMed

    Sainz-Gonzalo, F J; Popovici, C; Casimiro, M; Raya-Barón, A; López-Ortiz, F; Fernández, I; Fernández-Sánchez, J F; Fernández-Gutiérrez, A

    2013-10-21

    A new europium(III) membrane luminescent sensor based on a new tridentate bis(phosphinic acid)phosphine oxide (3) system has been developed. The synthesis of this new ligand is described and its full characterization by NMR, IR and elemental analyses is provided. The luminescent complex formed between europium(III) chloride and ligand 3 was evaluated in solution, observing that its spectroscopic and chemical characteristics are excellent for measuring in polymer inclusion membranes. Included in a Nafion membrane, all the parameters (ligand and ionic additives) that can affect the sensitivity and selectivity of the sensing membrane as well as the instrumental conditions were carefully optimized. The best luminescence signal (λexc = 229.06 nm and λem = 616.02 nm) was exhibited by the sensing film having a Nafion : ligand composition of 262.3 : 0.6 mg mL(-1). The membrane sensor showed a short response time (t95 = 5.0 ± 0.2 min) and an optimum working pH of 5.0 (25 mM acetate buffer solution). The membrane sensor manifested a good selectivity toward europium(III) ions with respect to other trivalent metals (iron, chromium and aluminium) and lanthanide(III) ions (lanthanum, samarium, terbium and ytterbium), although a small positive interference of terbium(III) ions was observed. It provided a linear range from 1.9 × 10(-8) to 5.0 × 10(-6) M with a very low detection limit (5.8 × 10(-9) M) and sensitivity (8.57 × 10(-7) a.u. per M). The applicability of this sensing film has been demonstrated by analyzing different kinds of spiked water samples obtaining recovery percentages of 95-97%.

  10. 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

    2016-01-14

    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.

  11. 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.

  12. Detection and characterisation of strong resistance to phosphine in Brazilian Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae).

    PubMed

    Lorini, Irineu; Collins, Patrick J; Daglish, Gregory J; Nayak, Manoj K; Pavic, Hervoika

    2007-04-01

    As failure to control Rhyzopertha dominica (F.) with phosphine is a common problem in the grain-growing regions of Brazil, a study was undertaken to investigate the frequency, distribution and strength of phosphine resistance in R. dominica in Brazil. Nineteen samples of R. dominica were collected between 1991 and 2003 from central storages where phosphine fumigation had failed to control this species. Insects were cultured without selection until testing in 2005. Each sample was tested for resistance to phosphine on the basis of the response of adults to discriminating concentrations of phosphine (20 and 48 h exposures) and full dose-response assays (48 h exposure). Responses of the Brazilian R. dominica samples were compared with reference susceptible, weak-resistance and strong-resistance strains from Australia in parallel assays. All Brazilian population samples showed resistance to phosphine: five were diagnosed with weak resistance and 14 with strong resistance. Five samples showed levels of resistance similar to the reference strong-resistance strain. A representative highly resistant sample was characterised by exposing mixed-age cultures to a range of constant concentrations of phosphine for various exposure periods. Time to population extinction (TPE) and time to 99.9% suppression of population (LT(99.9)) values of this sample were generally similar to those of the reference strong-resistance strain. For example, at 0.1, 0.5 and 1.0 mg L(-1), LT(99.9) values for BR33 and the reference strong-resistance strain were respectively 21, 6.4 and 3.7 days and 17, 6.2 and 3.8 days. With both strains, doubling phosphine concentrations to 2 mg L(-1) resulted in increased LT(99.9) and TPE. High level and frequency of resistance in all population samples, some of which had been cultured without selection for up to 12 years, suggest little or no fitness deficit associated with phosphine resistance. The present research indicates that widespread phosphine resistance may

  13. Determination of phosphine in biogas and sludge at ppt-levels with gas chromatography-thermionic specific detection.

    PubMed

    Roels, Joris; Van Langenhove, Herman; Verstraete, Willy

    2002-04-01

    A gas chromatographic (GC) system to measure free phosphine in biogas and matrix bound phosphine in manure and sludge is presented. The system consists of a sample preconcentration trap filled with glass beads, connected with a capillary GC equipped with a thermionic specific detector. With a trap temperature as low as -155 degrees C, a sampling flow of 20 ml/min and a typical total sample volume of 100 ml, free phosphine concentrations in the low ng/m3 range and matrix bound phosphine in the low ng/kg dry matter range, can be accurately and reproducibly determined.

  14. Synthesis and Coordination Chemistry of Phosphine Oxide Decorated Dibenzofuran Platforms

    SciTech Connect

    Rosario-Amorin, Daniel; Duesler, Eileen N.; Paine, Robert T.; Hay, Benjamin; Delmau, Laetitia Helene; Reilly, Sean D.; Gaunt, Andrew J.; Scott, Brian L.

    2012-01-01

    A four-step synthesis for 4,6-bis(diphenylphosphinoylmethyl)dibenzofuran (4) from dibenzofuran and a two-step synthesis for 4,6-bis(diphenylphosphinoyl)dibenzofuran (5) are reported along with coordination chemistry of 4 with In(III), La(III), Pr(III), Nd(III), Er(III), and Pu(IV) and of 5 with Er(III). Crystal structure determinations for the ligands, 4 {center_dot} CH{sub 3}OH and 5, the 1:1 complexes [In(4)(NO{sub 3}){sub 3}], [Pr(4)(NO{sub 3}){sub 3}(CH{sub 3}CN)] {center_dot} 0.5CH{sub 3}CN, [Er(4)(NO{sub 3}){sub 3}(CH{sub 3}CN)] {center_dot} CH{sub 3}CN, [Pu(4)Cl4] {center_dot} THF and the 2:1 complex [Nd(4){sub 2}(NO{sub 3}){sub 2}]{sub 2}(NO{sub 3}){sub 2} {center_dot} (H{sub 2}O) {center_dot} 4(CH{sub 3}OH) are described. In these complexes, ligand 4 coordinates in a bidentate POP{prime}O{prime} mode via the two phosphine oxide O-atoms. The dibenzofuran ring O-atom points toward the central metal cations, but in every case it is more than 4 {angstrom} from the metal. A similar bidentate POP{prime}O{prime} chelate structure is formed between 5 and Er(III) in the complex, {l_brace}[Er(5){sub 2}(NO{sub 3}){sub 2}](NO{sub 3}) {center_dot} 4(CH{sub 3}OH){r_brace}0.5, although the nonbonded Er{hor_ellipsis} O{sub furan} distance is reduced to 3.6 {angstrom}. The observed bidentate chelation modes for 4 and 5 are consistent with results from molecular mechanics computations. The solvent extraction performance of 4 and 5 in 1,2-dichloroethane for Eu(III) and Am(III) in nitric acid solutions is described and compared against the extraction behavior of n-octyl(phenyl)-N,N-diisobutylcarbamoylmethyl phosphine oxide (O{Phi}DiBCMPO) measured under identical conditions.

  15. 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).

  16. A computed room temperature line list for phosphine

    NASA Astrophysics Data System (ADS)

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

    2013-06-01

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

  17. 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

  18. Phosphine-gold(I) compounds as anticancer agents: general description and mechanisms of action.

    PubMed

    Lima, João Carlos; Rodriguez, Laura

    2011-12-01

    Gold complexes have been explored as metallodrugs with great potential applications as antitumoral agents. In particular, gold-phosphine derivatives seemed quite promising since the use of the antiarthritic auranofin drug (thiolate-Au-PEt3 complex) presented also biological activity against different cancer cells. So, different auranofin analogues have been explored within this context and for this reason, the main number of phosphine-gold complexes developed with this goal contain thiolate ligands. Other complexes have been also studied such as tetrahedral bis(phosphine)gold(I) and phosphine-gold-halides. Very recently, phosphine-gold-alkynyl complexes have also shown very interesting biological activities although few reports are published related to them. Their mechanism of action seems to be clearly different that the used by platinum drugs (DNA intercalating processes) and recent studies point to be related to the inhibition of Trx reductase. Cellular uptake and biodistribution studies are well reported in the original works but the use of luminescence techniques is relatively less explored. For this, the use of these techniques is also specifically reported in this review.

  19. 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.

  20. 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.

  1. Spread of phosphine resistance among brazilian populations of three species of stored product insects.

    PubMed

    Pimentel, Marco A G; Faroni, Lêda R D'A; Silva, Felipe H da; Batista, Maurílio D; Guedes, Raul N C

    2010-01-01

    The resistance to fumigant insecticides in stored-products insects is often recorded. Several factors influence the evolution of insecticide resistance. Among these, the frequency of applications and the migration of resistant populations are of primary importance for the stored-product insects. The aim of this study was to characterize the spectrum and investigate the status of phosphine resistance in Brazil, in 13 populations of the Coleoptera Tribolium castaneum Herbst (Tenebrionidae), ten populations of Rhyzopertha dominica (Fabr.) (Bostrichidae), and eight populations of Oryzaephilus surinamensis (L.) (Silvanidae). The pattern of resistance dispersion in the populations of these species was also verified. The bioassays for the detection of phosphine resistance followed the FAO standard method. To test the influence of migration in the evolution of the phosphine resistance, the difference of mortality in the discriminating concentration and the geographical distance among each pair wise combination of collection sites were correlated. None of the populations exhibited mortality above 90% in the discriminating concentration, for the three species. Mortality in the discriminating concentration increased with the geographical distance for R.dominica and O.surinamensis. However, no significant linear response was observed among the variables for T.castaneum populations. These results suggest that the dispersion of insects and the local selection are relevant in the evolution of the phosphine resistance in populations of R.dominica and O.surinamensis. In contrast, grain trade and local selection are probably the factors that determine the evolution of the phosphine resistance in populations of T. castaneum.

  2. 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.

  3. Synthesis and structural characterization of isolable phosphine coinage metal π-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 carbon–carbon 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 η2-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 η2-coordinated alkene.

  4. Stereoselective Synthesis of α-Amino-C-phosphinic Acids and Derivatives.

    PubMed

    Viveros-Ceballos, José Luis; Ordóñez, Mario; Sayago, Francisco J; Cativiela, Carlos

    2016-01-01

    α-Amino-C-phosphinic acids and derivatives are an important group of compounds of synthetic and medicinal interest and particular attention has been dedicated to their stereoselective synthesis in recent years. Among these, phosphinic pseudopeptides have acquired pharmacological importance in influencing physiologic and pathologic processes, primarily acting as inhibitors for proteolytic enzymes where molecular stereochemistry has proven to be critical. This review summarizes the latest developments in the asymmetric synthesis of acyclic and phosphacyclic α-amino-C-phosphinic acids and derivatives, following in the first case an order according to the strategy used, whereas for cyclic compounds the nitrogen embedding in the heterocyclic core is considered. In addition selected examples of pharmacological implications of title compounds are also disclosed. PMID:27589703

  5. Rapid and selective nitroxyl (HNO) trapping by phosphines: kinetics and new aqueous ligations for HNO detection and quantitation

    PubMed Central

    Reisz, Julie A.; Zink, Charles N.; King, S. Bruce

    2011-01-01

    Recent studies distinguish the biological and pharmacological effects of nitroxyl (HNO) from its oxidized/deprotonated product nitric oxide (NO), but lack of HNO detection methods limits understanding its in vivo mechanisms and the identification of endogenous sources. We previously demonstrated that reaction of HNO with triarylphosphines provides aza-ylides and HNO-derived amides, which may serve as stable HNO biomarkers. We now report a kinetic analysis for the trapping of HNO by phosphines, ligations of enzyme-generated HNO, and compatibility studies illustrating the selectivity of phosphines for HNO over other physiologically relevant nitrogen oxides. Quantification of HNO using phosphines is demonstrated using an HPLC-based assay and ligations of phosphine carbamates generate HNO-derived ureas. These results further demonstrate the potential of phosphine probes for reliable biological detection and quantification of HNO. PMID:21699183

  6. Phosphine resistance in Tribolium castaneum and Rhyzopertha dominica from stored wheat in Oklahoma.

    PubMed

    Opit, G P; Phillips, T W; Aikins, M J; Hasan, M M

    2012-08-01

    Phosphine gas, or hydrogen phosphide (PH3), is the most common insecticide applied to durable stored products worldwide and is routinely used in the United States for treatment of bulk-stored cereal grains and other durable stored products. Research from the late 1980s revealed low frequencies of resistance to various residual grain protectant insecticides and to phosphine in grain insect species collected in Oklahoma. The present work, which used the same previously established discriminating dose bioassays for phosphine toxicity as in the earlier study, evaluated adults of nine different populations of red flour beetle, Tribolium castaneum (Herbst), and five populations of lesser grain borer, Rhyzopertha dominica (F.) collected from different geographic locations in Oklahoma. One additional population for each species was a laboratory susceptible strain. Discriminating dose assays determined eight out of the nine T. castaneum populations, and all five populations of R. dominica, contained phosphine-resistant individuals, and highest resistance frequencies were 94 and 98%, respectively. Dose-response bioassays and logit analyses determined that LC99 values were approximately 3 ppm for susceptible and 377 ppm for resistant T. castaneum, and approximately 2 ppm for susceptible and 3,430 ppm for resistant R. dominica. The most resistant T. castaneum population was 119-fold more resistant than the susceptible strain and the most resistant R. dominica population was over 1,500-fold more resistant. Results suggest a substantial increase in phosphine resistance in these major stored-wheat pests in the past 21 yr, and these levels of resistance to phosphine approach those reported for other stored-grain pest species in other countries.

  7. Luminescence Solvato- and Vapochromism of Alkynyl-Phosphine Copper Clusters.

    PubMed

    Krytchankou, Ilya S; Koshevoy, Igor O; Gurzhiy, Vladislav V; Pomogaev, Vladimir A; Tunik, Sergey P

    2015-09-01

    The reaction of [Cu(NCMe)4][PF6] with aromatic acetylenes HC2R and triphosphine 1,1,1-tris(diphenylphosphino)methane in the presence of NEt3 results in the formation of hexanuclear Cu(I) clusters with the general formula [Cu6(C2R)4{(PPh2)3CH}2][PF6]2 (R = 4-X-C6H4 (1-5) and C5H4N (6); X = NMe2 (1), OMe (2), H (3), Ph (4), CF3 (5)). The structural motif of the complexes studied consists of a Cu6 metal core supported by two phosphine ligands and stabilized by σ- and π-coordination of the alkynyl fragments (together with coordination of pyridine nitrogen atoms in cluster 6). The solid state structures of complexes 2-6 were determined by single crystal XRD analysis. The structures of the complexes in solution were elucidated by (1)H, (31)P, (1)H-(1)H COSY NMR spectroscopy, and ESI mass spectrometry. Clusters 1-6 exhibit moderately strong phosphorescence in the solid state with quantum yields up to 17%. Complexes 1-5 were found to form solvates (acetone, acetonitrile) in the solid state. The coordination of loosely bound solvent molecules strongly affects emission characteristics and leads to solvato- and vapochromic behavior of the clusters. Thus, solvent-free and acetonitrile solvated forms of 3 demonstrate contrasting emission in orange (615 nm) and blue (475 nm) regions, respectively. The computational studies show that alkynyl-centered IL transitions mixed with those of MLCT between the Cu6 metal core and the ligand environment play a dominant role in the formation of excited states and can be considerably modulated by weakly coordinating solvent molecules leading to luminescence vapochromism. PMID:26262819

  8. Adjustable coordination of a hybrid phosphine-phosphine oxide ligand in luminescent Cu, Ag and Au complexes.

    PubMed

    Dau, Thuy Minh; Asamoah, Benjamin Darko; Belyaev, Andrey; Chakkaradhari, Gomathy; Hirva, Pipsa; Jänis, Janne; Grachova, Elena V; Tunik, Sergey P; Koshevoy, Igor O

    2016-09-28

    A potentially tridentate hemilabile ligand, PPh2-C6H4-PPh(O)-C6H4-PPh2 (P(3)O), has been used for the construction of a family of bimetallic complexes [MM'(P(3)O)2](2+) (M = M' = Cu (1), Ag (2), Au (3); M = Au, M' = Cu (4)) and their mononuclear halide congeners M(P(3)O)Hal (M = Cu (5-7), Ag (8-10)). Compounds 1-10 have been characterized in the solid state by single-crystal X-ray diffraction analysis to reveal a variable coordination mode of the phosphine-oxide group of the P(3)O ligand depending on the preferable number of coordination vacancies on the metal center. According to the theoretical studies, the interaction of the hard donor P[double bond, length as m-dash]O moiety with d(10) ions becomes less effective in the order Cu > Ag > Au. 1-10 exhibit room temperature luminescence in the solid state, and the intensity and energy of emission are mostly determined by the nature of metal atoms. The photophysical characteristics of the monometallic species were compared with those of the related compounds M(P(3))Hal (11-16) with the non-oxidized ligand P(3). It was found that in the case of the copper complexes 5-7 the P(3)O hybrid ligand introduces effective non-radiative pathways of the excited state relaxation leading to poor emission, while for the silver luminophores the P[double bond, length as m-dash]O group leads mainly to the modulation of luminescence wavelength. PMID:27530362

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

    PubMed

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

    2016-02-21

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

  10. 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.

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

    PubMed

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

    2016-05-16

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

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

    PubMed

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

    2016-05-16

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

  13. 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…

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

    PubMed Central

    Coudray, Laëtitia

    2013-01-01

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

  15. 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.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  17. 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.

  18. 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.

  19. Bis(mesitoyl)phosphinic acid: photo-triggered release of metaphosphorous acid in solution.

    PubMed

    Fast, David E; Zalibera, Michal; Lauer, Andrea; Eibel, Anna; Schweigert, Caroline; Kelterer, Anne-Marie; Spichty, Martin; Neshchadin, Dmytro; Voll, Dominik; Ernst, Hanna; Liang, Yu; Dietliker, Kurt; Unterreiner, Andreas-Neil; Barner-Kowollik, Christopher; Grützmacher, Hansjörg; Gescheidt, Georg

    2016-08-01

    Bis(mesitoyl)phosphinic acid and its sodium salt display a unique photo-induced reactivity: both derivatives stepwise release two mesitoyl radicals and, remarkably, metaphosphorous acid (previously postulated as transient species in the gas phase), providing a new phosphorus-based reagent. PMID:27431207

  20. 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

    2014-11-14

    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.

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

    PubMed

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

    2016-02-21

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

  2. 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

  3. Laboratory Studies of Phosphine Chemistry Relevant to the Jovian and Saturnian Atmospheres

    NASA Astrophysics Data System (ADS)

    Liu, Yingdi; Matsiev, Daniel; Robertson, Robert; White, Jason

    2016-10-01

    The photochemistry of phosphine (PH3) in the tropospheres of Saturn and Jupiter is initiated by ultraviolet (UV) radiation and then follows a cascade of chemical reactions that result in P-H hydrides as well as the condensed chromophore red phosphorus (P4). A key intermediate in this pathway is diphosphine (P2H4). The rate constants for the photodissociation of phosphine into initial phosphino radicals and consequently into formation of diphosphine are currently unavailable, limiting their applicability to observational measurements. The condensation of diphosphine to ice in the cold tropospheres is also poorly understood due to the difficulties in synthesizing, handling, and analyzing the compound.Our presentation will describe two experiments at SRI International to produce rate constants for the photochemistry initiated by UV light interacting with phosphine and diphosphine and properties related to the condensed phases of these species. One study seeks to produce property values for application in photochemical and cloud/haze models. Specifically, we extend the measured vapor pressure curve for diphosphine to temperatures relevant to temperatures of Saturn and Jupiter. A sophisticated vapor pressure cell has been constructed and tested and is coupled to a Fourier transform infrared (FTIR) and mass spectrometer for high-fidelity species diagnostics. A companion study investigates phosphine photochemistry to measure the rate constants of key intermediate species related to the loss of PH3 and the formation of P2H4. The experiments employ laser photolysis at 193 nm followed by time-resolved mid-IR laser-based species detection of reactants, and the products provide basic chemical kinetic data useful for interpreting phosphine photochemistry in planetary atmospheres.These two studies are intended to supply basic physical measurements to aid in the interpretation of outer planet atmospheric observations. For both studies, we will present our latest laboratory

  4. Iridium-catalysed dehydrocoupling of aryl phosphine-borane adducts: synthesis and characterisation of high molecular weight poly(phosphinoboranes).

    PubMed

    Paul, Ursula S D; Braunschweig, Holger; Radius, Udo

    2016-06-30

    The thermal dehydrogenative coupling of aryl phosphine-borane adducts with iridium complexes bearing a bis(phosphinite) pincer ligand is reported. This catalysis produces high molecular weight poly(phosphinoboranes) [ArPH-BH2]n (Ar = Ph, (p)Tol, Mes). Furthermore, we investigated the reactivity of these pincer complexes towards primary phosphines and their respective borane adducts on a stoichiometric scale. PMID:27320239

  5. Three- versus four-coordinate phosphorus in the gas phase and in solution: Treacherous relative energies for phosphine oxide and phosphinous acid

    NASA Astrophysics Data System (ADS)

    Wesolowski, Steven S.; Brinkmann, Nicole R.; Valeev, Edward F.; Schaefer, Henry F.; Repasky, Matthew P.; Jorgensen, William L.

    2002-01-01

    Previous ab initio studies have consistently predicted phosphine oxide (H3PO) to be less stable than its nearly isoenergetic cis- and trans-phosphinous acid isomers (H2POH). However, complete basis set extrapolations employing the coupled-cluster series show that phosphine oxide is actually ca. 1.0 kcal/mol more stable than its acid forms in the gas phase. Incorporation of tight d functions via Dunning's core-valence (cc-pCVXZ) or newly constructed "plus d" [cc-pV(X+d)Z] basis sets is essential for rapid convergence of core polarization effects which are evident even at the SCF level. The precision to which the phosphorus hybridization is described in the three- and four-coordinate environments ultimately determines the predicted gas-phase relative energy orderings. Focal-point analyses demonstrate that this system represents a disturbing case where use of a conventional valence quadruple-ζ quality basis set (cc-pVQZ)—even at the CCSD(T) level—fails to provide the correct relative energy ordering for simple closed-shell species which do not exhibit appreciable multireference character. Thus, we underscore the importance of using phosphorus basis sets which have the flexibility to describe core polarization adequately. In addition, Monte Carlo (MC) free-energy perturbation simulations in solution clearly demonstrate that the small energy gap significantly increases in favor of the oxide (10.0 kcal/mol) upon solvation due to stronger hydrogen bonding with the highly polar Pδ+→Oδ- bond.

  6. 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 5°C. 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.

  7. 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.

  8. 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.

  9. Simple phosphinate ligands access zinc clusters identified in the synthesis of zinc oxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Pike, Sebastian D.; White, Edward R.; Shaffer, Milo S. P.; Williams, Charlotte K.

    2016-10-01

    The bottom-up synthesis of ligand-stabilized functional nanoparticles from molecular precursors is widely applied but is difficult to study mechanistically. Here we use 31P NMR spectroscopy to follow the trajectory of phosphinate ligands during the synthesis of a range of ligated zinc oxo clusters, containing 4, 6 and 11 zinc atoms. Using an organometallic route, the clusters interconvert rapidly and self-assemble in solution based on thermodynamic equilibria rather than nucleation kinetics. These clusters are also identified in situ during the synthesis of phosphinate-capped zinc oxide nanoparticles. Unexpectedly, the ligand is sequestered to a stable Zn11 cluster during the majority of the synthesis and only becomes coordinated to the nanoparticle surface, in the final step. In addition to a versatile and accessible route to (optionally doped) zinc clusters, the findings provide an understanding of the role of well-defined molecular precursors during the synthesis of small (2-4 nm) nanoparticles.

  10. Molybdenum(0) Dinitrogen Complexes Supported by Pentadentate Tetrapodal Phosphine Ligands: Structure, Synthesis, and Reactivity toward Acids.

    PubMed

    Hinrichsen, Svea; Kindjajev, Andrei; Adomeit, Sven; Krahmer, Jan; Näther, Christian; Tuczek, Felix

    2016-09-01

    The syntheses of two pentadentate tetrapodal phosphine (pentaPod(P)) ligands, P2(Ph)PP2(Ph) and P2(Me)PP2(Ph), are reported, which derive from the fusion of a tripod and a trident ligand. Reaction of the ligand P2(Ph)PP2(Ph) with [MoCl3(THF)3] followed by an amalgam reduction under N2 does not lead to well-defined products. The same reactions performed with the ligand P2(Me)PP2(Ph) afford the mononuclear molybdenum dinitrogen complex [MoN2(P2(Me)PP2(Ph))]. Because of the unprecedented topology of the pentaphosphine ligand, the Mo-P bond to the phosphine in the trans position to N2 is significantly shortened, explaining the very strong activation of the dinitrogen ligand (ν̃NN = 1929 cm(-1)). The reactivity of this complex toward acids is investigated. PMID:27526268

  11. 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.

  12. FTIR spectra of the photolysis products of the phosphine-ozone complex in solid argon

    SciTech Connect

    Withnall, R.; Andrews, L.

    1987-02-12

    Red visible photolysis of the PH/sub 3/-O/sub 3/ complex, formed by reagent codeposition with excess argon at 12-18 K, gave seven major products, which are grouped by wavelength-dependent photochemical changes and identified by using /sup 16,18/O/sub 3/ and PH/sub x/D/sub 3-x/ (x = 0, 1, 2, 3) mixed isotopic precursors. The primary products are phosphine oxide (H/sub 3/PO) and phosphinous acid (H/sub 2/POH), structural isomers that were not interconverted by further irradiation, and phosphonic acid ((HO)/sub 2/HPO). The intermediate species HPO, also produced on red photolysis, gave way to HOOPO and HP(O/sub 2/)O on blue-green irradiation. Metaphosphoric acid (HOPO/sub 2/) absorptions increased throughout the irradiation sequence.

  13. 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.

  14. Redox reactions of [FeFe]-hydrogenase models containing an internal amine and a pendant phosphine.

    PubMed

    Zheng, Dehua; Wang, Mei; Chen, Lin; Wang, Ning; Sun, Licheng

    2014-02-01

    A diiron dithiolate complex with a pendant phosphine coordinated to one of the iron centers, [(μ-SCH2)2N(CH2C6H4-o-PPh2){Fe2(CO)5}] (1), was prepared and structurally characterized. The pendant phosphine is dissociated together with a CO ligand in the presence of excess PMe3, to afford [(μ-SCH2)2N(CH2C6H4-o-PPh2){Fe(CO)2(PMe3)}2] (2). Redox reactions of 2 and related complexes were studied in detail by in situ IR spectroscopy. A series of new Fe(II)Fe(I) ([3](+) and [6](+)), Fe(II)Fe(II) ([4](2+)), and Fe(I)Fe(I) (5) complexes relevant to Hox, Hox(CO), and Hred states of the [FeFe]-hydrogenase active site were detected. Among these complexes, the molecular structures of the diferrous complex [4](2+) with the internal amine and the pendant phosphine co-coordinated to the same iron center and the triphosphine diiron complex 5 were determined by X-ray crystallography. To make a comparison, the redox reactions of an analogous complex, [(μ-SCH2)2N(CH2C6H5){Fe(CO)2(PMe3)}2] (7), were also investigated by in situ IR spectroscopy in the absence or presence of extrinsic PPh3, which has no influence on the oxidation reaction of 7. The pendant phosphine in the second coordination sphere makes the redox reaction of 2 different from that of its analogue 7.

  15. Electron-rich linear triplatinum complexes stabilized by a spinning tetraphosphine, tris(diphenylphosphinomethyl)phosphine.

    PubMed

    Tanase, Tomoaki; Koike, Kanako; Uegaki, Miho; Hatada, Satoko; Nakamae, Kanako; Kure, Bunsho; Ura, Yasuyuki; Nakajima, Takayuki

    2016-05-01

    Linear triplatinum complexes with 48e(-), [Pt3(μ-tdpmp)2(RNC)2](PF6)2 (R = 2,6-xylyl (3), (t)Bu (4)), were synthesized by using a branched tetraphosphine, tris(diphenylphosphinomethyl)phosphine (tdpmp), and characterized by crystallographic and spectroscopic analyses to show their novel dynamic behaviour in the solution state, in which the linear Pt3 unit was stabilized by two spinning tetraphosphine ligands.

  16. Phosphine-catalyzed asymmetric additions of malonate esters to γ-substituted allenoates and allenamides

    PubMed Central

    Sinisi, Riccardo; Sun, Jianwei; Fu, Gregory C.

    2010-01-01

    Because carbonyl groups are ubiquitous in organic chemistry, the ability to synthesize functionalized carbonyl compounds, particularly enantioselectively, is an important objective. We have developed a straightforward and versatile method for catalytic asymmetric carbon–carbon bond formation at the γ-position of carbonyl compounds, specifically, phosphine-catalyzed additions of malonate esters to γ-substituted allenoates and allenamides. Mechanistic studies have provided insight into the reaction pathway. PMID:20624987

  17. Phosphine-Catalyzed [3+2] and [4+3]Annulation Reactions of C,N-Cyclic Azomethine Imines with Allenoates

    PubMed Central

    Jing, Chengfeng; Na, Risong; Wang, Bo; Liu, Honglei; Zhang, Lei; Liu, Jun; Wang, Min; Kwon, Ohyun

    2014-01-01

    Phosphine-catalyzed [3+2] and [4+3]annulation reactions of C,N-cyclic azomethine imines with allenoates have been developed to give a variety of pharmaceutically attractive tetrahydroisoquinoline derivatives in moderate to excellent yields. The two distinct reaction pathways, [3+2] and [4+3]cyclization, depend on the nature of the nucleophilic phosphine and the allenoate. Generally, for α-alkylallenoates, the reactions always proceed with [3 +2]cyclization as the major pathway no matter what phosphine was used; for α-ArCH2-substituted allenoates, the reaction pathway was controlled by the phosphine catalyst used. PMID:25525424

  18. Computer-Aided Molecular Design of Bis-phosphine Oxide Lanthanide Extractants

    DOE PAGES

    McCann, Billy W.; Silva, Nuwan De; Windus, Theresa L.; Gordon, Mark S.; Moyer, Bruce A.; Bryantsev, Vyacheslav S.; Hay, Benjamin P.

    2016-02-17

    Computer-aided molecular design and high-throughput screening of viable host architectures can significantly reduce the efforts in the design of novel ligands for efficient extraction of rare earth elements. This paper presents a computational approach to the deliberate design of bis-phosphine oxide host architectures that are structurally organized for complexation of trivalent lanthanides. Molecule building software, HostDesigner, was interfaced with molecular mechanics software, PCModel, providing a tool for generating and screening millions of potential R2(O)P-link-P(O)R2 ligand geometries. The molecular mechanics ranking of ligand structures is consistent with both the solution-phase free energies of complexation obtained with density functional theory and themore » performance of known bis-phosphine oxide extractants. For the case where link is -CH2-, evaluation of the ligand geometry provides the first characterization of a steric origin for the ‘anomalous aryl strengthening’ effect. The design approach has identified a number of novel bis-phosphine oxide ligands that are better organized for lanthanide complexation than previously studied examples.« less

  19. Gas chromatography-mass spectrometry determination of phosphine residues in stored products and processed foods.

    PubMed

    Norman, K N; Leonard, K

    2000-09-01

    A gas chromatography-mass spectrometry (GC-MS) method was used for the quantitative confirmation of phosphine residues in stored products and processed foods. An established extraction technique was utilized for the preparation of headspace samples, which were analyzed by GC-MS and gas chromatography-nitrogen-phosphorus detection (GC-NPD). Wheat, oats, maize, white rice, brown rice, cornflakes, tortilla cornchips, groundnuts, and raisins were validated, showing excellent agreement between detectors when spiked at levels equivalent to 0.001 and 0.01 mg/kg phosphine and for samples containing incurred residues. The GC-MS method was reproducible and accurate when compared to the GC-NPD method and allowed five samples to be quantified in a working day. Subambient GC-MS oven temperatures were most suitable for phosphine residues ranging from 0.001 to 0.005 mg/kg, and a GC oven temperature of 100 degrees C was appropriate for residues >0.005 mg/kg. The method was sufficiently robust to be evaluated for other similar commodities as the need arises.

  20. 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.

  1. Computer-Aided Molecular Design of Bis-phosphine Oxide Lanthanide Extractants.

    PubMed

    McCann, Billy W; Silva, Nuwan De; Windus, Theresa L; Gordon, Mark S; Moyer, Bruce A; Bryantsev, Vyacheslav S; Hay, Benjamin P

    2016-06-20

    Computer-aided molecular design and high-throughput screening of viable host architectures can significantly reduce the efforts in the design of novel ligands for efficient extraction of rare earth elements. This paper presents a computational approach to the deliberate design of bis-phosphine oxide host architectures that are structurally organized for complexation of trivalent lanthanides. Molecule building software, HostDesigner, was interfaced with molecular mechanics software, PCModel, providing a tool for generating and screening millions of potential R2(O)P-link-P(O)R2 ligand geometries. The molecular mechanics ranking of ligand structures is consistent with both the solution-phase free energies of complexation obtained with density functional theory and the performance of known bis-phosphine oxide extractants. For the case where the link is -CH2-, evaluation of the ligand geometry provides the first characterization of a steric origin for the "anomalous aryl strengthening" effect. The design approach has identified a number of novel bis-phosphine oxide ligands that are better organized for lanthanide complexation than previously studied examples.

  2. 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

  3. Synthesis and Coordination Chemistry of a Phosphine-Decorated Fluorescein: "Double Turn-On" Sensing of Gold(III) Ions in Water.

    PubMed

    Christianson, Anna M; Gabbaï, François P

    2016-06-20

    Although phosphine ligands are ubiquitous in transition metal chemistry, few reports of fluorescent phosphines exist that explore the effect of metal coordination on the photophysical properties of a phosphine-bound fluorescent group. The coordination chemistry of a derivative of fluorescein decorated with an o-phenylene-linked phosphine group has been studied with late transition metals. An Au(I) complex of the phosphine-decorated fluorescein has been structurally characterized, showing that the metal center is held closely over the plane of the fluorophore. Despite the presence of the heavy metal center, however, the phosphine-gold complex displays greatly increased fluorescence compared to the free ligand, in which photoelectron transfer from the lone-pair-bearing phosphine causes low emission. The phosphine-decorated fluorescein ligand was tested in a simple sensing system for metal ions in aqueous solution and shows a "turn-on" response to Au, Ag, and Hg, with an especially dramatic response to Au(III) species. The selectivity for Au(III) was determined to be the result of a "double turn-on" response that is both reaction- and coordination-based.

  4. Multicomponent reactions of phosphines, diynedioates, and aryl aldehydes generated furans appending reactive phosphorus ylides through cumulated trienoates as key intermediates: a phosphine α-addition-δ-evolvement of an anion pathway.

    PubMed

    Deng, Jie-Cheng; Chuang, Shih-Ching

    2014-11-01

    Multicomponent reactions of phosphines, diynedioates, and aryl aldehydes have been demonstrated, providing trisubstituted furans appending reactive phosphorus ylides, through cumulated trienoates as key intermediates. The proposed trienoate intermediates, 1,5-dipolar species formed via nucleophilic α-attack of phosphines toward diynedioates (α-addition-δ-evolvement of an anion, abbreviated αAδE), undergo addition to aryl aldehydes followed by 5-endo-dig cyclization, proton transfer, and resonance to give trisubstituted furans. Furthermore, the phosphorus ylides are oxidized to α-keto ester furans and utilized as Wittig reagents.

  5. A 2-pyridyl (py) attached phosphine imine [P(Npy)(NHpy)3] and an imido phosphinate ion [P(Npy)2)(NHpy)2]- in its Ag(I) complex.

    PubMed

    Gupta, Arvind K; Chipem, Francis A S; Boomishankar, Ramamoorthy

    2012-02-14

    A new phosphine imine 3, [P(Npy)(NHpy)(3)] (py = 2-pyridyl), was synthesized from the phosphonium salt 1, [P(NHpy)(4)]Cl. Subsequent reaction of 1 or 3 with AgClO(4) lead to an unprecedented penta-nuclear Ag(I) complex 4 stabilized by two [P(Npy)(2)(NHpy)(2)](-) anions [L](-). The packing diagram of 4 shows an interesting channel structure which contains solvated molecules of methanol and toluene. The diimine ligand [L](-), which represents the N-analogue of a phosphinate ion (H(2)PO(4)(-)), was obtained in situ under the mild reaction conditions in the absence of a base. PMID:22167162

  6. 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

  7. 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 0.36 mg 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.

  8. 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 0.36 mg 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

  9. 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 (ν7 = 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 PH3 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.

  10. Photophysical properties of endohedral amine-functionalized bis(phosphine) Pt(II) complexes as models for emissive metallacycles.

    PubMed

    Pollock, J Bryant; Cook, Timothy R; Schneider, Gregory L; Lutterman, Daniel A; Davies, Andrew S; Stang, Peter J

    2013-08-19

    The photophysical properties of bis(phosphine) Pt(II) complexes constructed from 2,6-bis(pyrid-3-ylethynyl) aniline and 2,6-bis(pyrid-4-ylethynyl) aniline vary significantly, even though the complexes differ only in the position of the coordinating nitrogen. By capping the ligands with an aryl bis(phosphine) Pt(II) metal acceptor, the photophysical properties of the two isomeric systems were directly compared, revealing that the low-energy absorption and emission bands of the two systems were separated by 30 nm (1804 cm(-1)) and 39 nm (1692 cm(-1)), respectively. From the analysis of time-dependent density functional (TD-DFT) calculations and excited-state lifetime measurements, it was determined that the nature of the Pt-N bond in the HOMO and the sums of the radiative (k(rad)) and nonradiative (k(nr)) rate constants were significantly different in the two systems. As the dominant nonradiative decay pathway in aniline systems is relaxation from the triplet state through intersystem crossing (ISC), the difference in k(nr) can be ascribed to changes in ISC between isomers of the bis(phosphine) Pt(II)-capped 2,6-bis(pyrid-3-ylethynyl) aniline system. It was also determined that the photophysical properties of these capped systems can be altered by functionalizing the aryl capping ligand on the bis(phosphine) Pt(II) metal center, which perturbs the molecular orbitals involved in the observed optical transitions. In addition, an isoelectronic bis(phosphine) Pd(II)-capped system was prepared for comparison with the bis(phosphine) Pt(II) suite of complexes. The Pd(II) system showed significant changes in its low-energy absorption band, but preserved the characteristic emissive properties of its Pt(II) analogue with an even higher quantum yield.

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

    DOEpatents

    Crabtree, Robert H.; Brown, Stephen H.

    1989-01-01

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

  12. 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.

  13. Methylene-bis[(aminomethyl)phosphinic acids]: synthesis, acid-base and coordination properties.

    PubMed

    David, Tomáš; Procházková, Soňa; Havlíčková, Jana; Kotek, Jan; Kubíček, Vojtěch; Hermann, Petr; Lukeš, Ivan

    2013-02-21

    Three symmetrical methylene-bis[(aminomethyl)phosphinic acids] bearing different substituents on the central carbon atom, (NH(2)CH(2))PO(2)H-C(R(1))(R(2))-PO(2)H(CH(2)NH(2)) where R(1) = OH, R(2) = Me (H(2)L(1)), R(1) = OH, R(2) = Ph (H(2)L(2)) and R(1),R(2) = H (H(2)L(3)), were synthesized. Acid-base and complexing properties of the ligands were studied in solution as well as in the solid state. The ligands show unusually high basicity of the nitrogen atoms (log K(1) = 9.5-10, log K(2) = 8.5-9) if compared with simple (aminomethyl)phosphinic acids and, consequently, high stability constants of the complexes with studied divalent metal ions. The study showed the important role of the hydroxo group attached to the central carbon atom of the geminal bis(phosphinate) moiety. Deprotonation of the hydroxo group yields the alcoholate anion which tends to play the role of a bridging ligand and induces formation of polynuclear complexes. Solid-state structures of complexes [H(2)N=C(NH(2))(2)][Cu(2)(H(-1)L(2))(2)]CO(3)·10H(2)O and Li(2)[Co(4)(H(-1)L(1))(3)(OH)]·17.5H(2)O were determined by X-ray diffraction. The complexes show unexpected geometries forming dinuclear and cubane-like structures, respectively. The dinuclear copper(II) complex contains a bridging μ(2)-alcoholate group with the (-)O-P(=O)-CH(2)-NH(2) fragments of each ligand molecule chelated to the different central ion. In the cubane cobalt(II) complex, one μ(3)-hydroxide and three μ(3)-alcoholate anions are located in the cube vertices and both phosphinate groups of one ligand molecule are chelating the same cobalt(II) ion while each of its amino groups are bound to different neighbouring metal ions. All such three metal ions are bridged by the alcoholate group of a given ligand.

  14. Inhalation of phosphine gas following a fire associated with fumigation of processed pistachio nuts.

    PubMed

    O'Malley, Michael; Fong, Harvard; Sánchez, Martha E; Roisman, Rachel; Nonato, Yvette; Mehler, Louise

    2013-01-01

    On December 10, 2009, a fumigation stack containing aluminum phosphide became soaked with rain water and caught fire at a pistachio processing plant in Kern County, California. Untrained plant personnel responding to the fire had exposure to pyrolysis by-products, particulates, and extinguisher ingredients. Ten workers taken for medical evaluation had respiratory and nonspecific systemic symptoms consistent with exposure to phosphine gas. Six of the 10 workers had respiratory distress, indicated by chest pain, shortness of breath, elevated respiratory rate, or decreased oxygen saturation. Recommendations are made for the management of similar illnesses and prevention of similar exposures.

  15. n-Type Doping of Germanium from Phosphine: Early Stages Resolved at the Atomic Level

    NASA Astrophysics Data System (ADS)

    Scappucci, G.; Warschkow, O.; Capellini, G.; Klesse, W. M.; McKenzie, D. R.; Simmons, M. Y.

    2012-08-01

    To understand the atomistic doping process of phosphorus in germanium, we present a combined scanning tunneling microscopy, temperature programed desorption, and density functional theory study of the reactions of phosphine with the Ge(001) surface. Combining experimental and theoretical results, we demonstrate that PH2+H with a footprint of one Ge dimer is the only product of room temperature chemisorption. Further dissociation requires thermal activation. At saturation coverage, PH2+H species self-assemble into ordered patterns leading to phosphorus coverages of up to 0.5 monolayers.

  16. Radical Reaction of Sodium Hypophosphite with Terminal Alkynes: Synthesis of 1,1-bis-H-Phosphinates

    PubMed Central

    Gouault-Bironneau, Sonia; Deprèle, Sylvine; Sutor, Amber; Montchamp, Jean-Luc

    2008-01-01

    The room temperature radical addition of sodium hypophosphite to terminal alkynes produces the previously unknown 1-alkyl-1,1-bis-H-phosphinates in moderate yield. The reaction is initiated by R3B and air and proceeds under mild conditions in an open container. The bis-sodium salts precipitate spontaneously from the reaction mixtures, thus providing a simple purification procedure and the opportunity for multigram synthesis. The 1,1-bis-H-phosphinate products are novel precursors of the biologically important 1,1-bisphosphonates. PMID:16354097

  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.

  18. 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

  19. Magnetometry and electron paramagnetic resonance studies of phosphine- and thiol-capped gold nanoparticles

    NASA Astrophysics Data System (ADS)

    Guerrero, E.; Muñoz-Márquez, M. A.; Fernández, A.; Crespo, P.; Hernando, A.; Lucena, R.; Conesa, J. C.

    2010-03-01

    In the last years, the number of studies performed by wholly independent research groups that confirm the permanent magnetism, first observed in our research lab, for thiol-capped Au nanoparticles (NPs) has rapidly increased. Throughout the years, the initial magnetometry studies have been completed with element-specific magnetization measurements based on, for example, the x-ray magnetic circular dichroism technique that have allowed the identification of gold as the magnetic moment carrier. In the research work here presented, we have focused our efforts in the evaluation of the magnetic behavior and iron impurities content in the synthesized samples by means of superconducting quantum interference device magnetometry and electron paramagnetic resonance spectrometry, respectively. As a result, hysteresis cycles typical of a ferromagnetic material have been measured from nominally iron-free gold NPs protected with thiol, phosphine, and chlorine ligands. It is also observed that for samples containing both, capped gold NPs and highly diluted iron concentrations, the magnetic behavior of the NPs is not affected by the presence of paramagnetic iron impurities. The hysteresis cycles reported for phosphine-chlorine-capped gold NPs confirm that the magnetic behavior is not exclusively for the metal-thiol system.

  20. 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.

  1. 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.

  2. Copper(i) complexes with phosphine derived from sparfloxacin. Part I - structures, spectroscopic properties and cytotoxicity.

    PubMed

    Komarnicka, Urszula K; Starosta, Radosław; Kyzioł, Agnieszka; Jeżowska-Bojczuk, Małgorzata

    2015-07-28

    In this paper we present new copper(i) iodide or copper(i) thiocyanate complexes with hydroxymethyldiphenylphosphine (PPh2(CH2OH)) or phosphine derivatives of sparfloxacin, a 3(rd) generation fluoroquinolone antibiotic agent (PPh2(CH2-Sf)) and 2,9-dimethyl-1,10-phenanthroline (dmp) or 2,2'-biquinoline (bq) auxiliary ligands. The synthesised complexes were fully characterised by NMR and UV-Vis spectroscopy as well as by mass spectrometry. Selected structures were additionally analysed using X-ray and DFT methods. All complexes proved to be stable in solution in the presence of water and atmospheric oxygen for several days. The cytotoxic activity of the complexes was tested against two cancer cell lines (CT26 - mouse colon carcinoma and A549 - human lung adenocarcinoma). Applying two different incubation times, the studies enabled a preliminary estimation of the dependence of the selectivity and the mechanism of action on the type of diimine and phosphine ligands. The results obtained showed that complexes with PPh2(CH2-Sf) are significantly more active than those with PPh2(CH2OH). On the other hand, the relative impact of diimine on cytotoxicity is less pronounced. However, the dmp complexes are characterised by strong inhibitory properties, while the bq ones are rather not. This confirms the interesting and promising biological properties of the investigated group of copper(i) complexes, which undoubtedly are worthy of further biological studies.

  3. Simple phosphinate ligands access zinc clusters identified in the synthesis of zinc oxide nanoparticles

    PubMed Central

    Pike, Sebastian D.; White, Edward R.; Shaffer, Milo S. P.; Williams, Charlotte K.

    2016-01-01

    The bottom-up synthesis of ligand-stabilized functional nanoparticles from molecular precursors is widely applied but is difficult to study mechanistically. Here we use 31P NMR spectroscopy to follow the trajectory of phosphinate ligands during the synthesis of a range of ligated zinc oxo clusters, containing 4, 6 and 11 zinc atoms. Using an organometallic route, the clusters interconvert rapidly and self-assemble in solution based on thermodynamic equilibria rather than nucleation kinetics. These clusters are also identified in situ during the synthesis of phosphinate-capped zinc oxide nanoparticles. Unexpectedly, the ligand is sequestered to a stable Zn11 cluster during the majority of the synthesis and only becomes coordinated to the nanoparticle surface, in the final step. In addition to a versatile and accessible route to (optionally doped) zinc clusters, the findings provide an understanding of the role of well-defined molecular precursors during the synthesis of small (2–4 nm) nanoparticles. PMID:27734828

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

    PubMed Central

    Keleş, Tuğba; Serindağ, Osman

    2014-01-01

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

  5. Bis(allyl)-ruthenium(iv) complexes with phosphinous acid ligands as catalysts for nitrile hydration reactions.

    PubMed

    Tomás-Mendivil, Eder; Francos, Javier; González-Fernández, Rebeca; González-Liste, Pedro J; Borge, Javier; Cadierno, Victorio

    2016-09-14

    Several mononuclear ruthenium(iv) complexes with phosphinous acid ligands [RuCl2(η(3):η(3)-C10H16)(PR2OH)] have been synthesized (78-86% yield) by treatment of the dimeric precursor [{RuCl(μ-Cl)(η(3):η(3)-C10H16)}2] (C10H16 = 2,7-dimethylocta-2,6-diene-1,8-diyl) with 2 equivalents of different aromatic, heteroaromatic and aliphatic secondary phosphine oxides R2P([double bond, length as m-dash]O)H. The compounds [RuCl2(η(3):η(3)-C10H16)(PR2OH)] could also be prepared, in similar yields, by hydrolysis of the P-Cl bond in the corresponding chlorophosphine-Ru(iv) derivatives [RuCl2(η(3):η(3)-C10H16)(PR2Cl)]. In addition to NMR and IR data, the X-ray crystal structures of representative examples are discussed. Moreover, the catalytic behaviour of complexes [RuCl2(η(3):η(3)-C10H16)(PR2OH)] has been investigated for the selective hydration of organonitriles in water. The best results were achieved with the complex [RuCl2(η(3):η(3)-C10H16)(PMe2OH)], which proved to be active under mild conditions (60 °C), with low metal loadings (1 mol%), and showing good functional group tolerance. PMID:27510460

  6. Bis(allyl)-ruthenium(iv) complexes with phosphinous acid ligands as catalysts for nitrile hydration reactions.

    PubMed

    Tomás-Mendivil, Eder; Francos, Javier; González-Fernández, Rebeca; González-Liste, Pedro J; Borge, Javier; Cadierno, Victorio

    2016-09-14

    Several mononuclear ruthenium(iv) complexes with phosphinous acid ligands [RuCl2(η(3):η(3)-C10H16)(PR2OH)] have been synthesized (78-86% yield) by treatment of the dimeric precursor [{RuCl(μ-Cl)(η(3):η(3)-C10H16)}2] (C10H16 = 2,7-dimethylocta-2,6-diene-1,8-diyl) with 2 equivalents of different aromatic, heteroaromatic and aliphatic secondary phosphine oxides R2P([double bond, length as m-dash]O)H. The compounds [RuCl2(η(3):η(3)-C10H16)(PR2OH)] could also be prepared, in similar yields, by hydrolysis of the P-Cl bond in the corresponding chlorophosphine-Ru(iv) derivatives [RuCl2(η(3):η(3)-C10H16)(PR2Cl)]. In addition to NMR and IR data, the X-ray crystal structures of representative examples are discussed. Moreover, the catalytic behaviour of complexes [RuCl2(η(3):η(3)-C10H16)(PR2OH)] has been investigated for the selective hydration of organonitriles in water. The best results were achieved with the complex [RuCl2(η(3):η(3)-C10H16)(PMe2OH)], which proved to be active under mild conditions (60 °C), with low metal loadings (1 mol%), and showing good functional group tolerance.

  7. 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.

  8. Bifunctional ferrocene-based squaramide-phosphine as an organocatalyst for highly enantioselective intramolecular Morita-Baylis-Hillman reaction.

    PubMed

    Zhang, Xiaorui; Ma, Pengfei; Zhang, Dongxu; Lei, Yang; Zhang, Shengyong; Jiang, Ru; Chen, Weiping

    2014-04-21

    This work demonstrates that, in accord with metal catalysis, ferrocene could be an excellent scaffold for organocatalysts. The simple and easily accessible bifunctional ferrocene-based squaramide-phosphine shows high enantioselectivity in the intramolecular Morita-Baylis-Hillman reaction of 7-aryl-7-oxo-5-heptenals, giving a variety of 2-aroyl-2-cyclohexenols in up to 96% ee.

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

    PubMed Central

    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

    2015-01-01

    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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  11. 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

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

    PubMed

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

    2015-09-01

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

  13. 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 ...

  14. Efficacies of spinosad and a combination of chlorpyrifos-methyl and deltamethrin against phosphine-resistant Rhyzopertha dominica (Coleoptera: Bostrichidae) and Tribolium castaneum (Coleoptera: Tenebrionidae) on wheat.

    PubMed

    Bajracharya, N S; Opit, George P; Talley, J; Jones, C L

    2013-10-01

    Highly phosphine-resistant populations of Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae) and Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) have recently been found in Oklahoma grain storage facilities. These findings necessitate development of a phosphine resistance management strategy to ensure continued effective use of phosphine. Therefore, we investigated the efficacies of two grain insecticides, namely, spinosad applied at label rate of 1 ppm and a mixture of chlorpyrifos-methyl and deltamethrin applied at label rates of 3 and 0.5 ppm, respectively, against highly phosphine-resistant R. dominica and T. castaneum. Adult mortality and progeny production suppression of spinosad- or chlorpyrifos-methyl + deltamethrin mixture-treated wheat that had been stored for 2, 84, 168, 252, and 336 d posttreatment were assessed. We found that both spinosad and chlorpyrifos-methyl + deltamethrin were effective against phosphine-resistant R. dominica and caused 83-100% mortality and also caused total progeny production suppression for all storage periods. Spinosad was not effective against phosphine-resistant T. castaneum; the highest mortality observed was only 3% for all the storage periods. Chlorpyrifos-methyl + deltamethrin was effective against phosphine-resistant T. castaneum only in treated wheat stored for 2 and 84 d, where it caused 93-99% mortality. However, chlorpyrifos-methyl + deltamethrin was effective and achieved total suppression of progeny production in T. castaneum for all the storage periods. Spinosad was not as effective as chlorpyrifos-methyl + deltamethrin mixture at suppressing progeny production of phosphine-resistant T. castaneum. These two insecticides can be used in a phosphine resistance management strategy for R. dominica and T. castaneum in the United States.

  15. Studies on the effects of phosphine on Salmonella enterica serotype Enteritidis in culture medium and in black pepper (Piper nigrum).

    PubMed

    Castro, M F P M; Rezende, A C B; Benato, E A; Valentini, S R T; Furlani, R P Z; Tfouni, S A V

    2011-04-01

    The effect of phosphine on Salmonella enterica serotype Enteritidis inoculated in culture medium and in black pepper grains (Piper nigrum), as well as on the reduction of the microbial load of the dried and moisturized product, was verified. The postfumigation effect was verified in inoculated samples with 0.92 and 0.97 water activity (a(w)) exposed to 6 g/m(3) phosphine for 72 h, dried to 0.67 a(w), and stored for 24, 48, and 72 h. No decreases were observed in Salmonella Enteritidis populations in culture medium when fumigant concentrations up to 6 g/m(3) were applied for 48 h at 35°C. However, the colonies showed reductions in size and atypical coloration as the phosphine concentration increased. No reduction in Salmonella counts occurred on the inoculated dried samples after fumigation. On the other hand, when phosphine at concentrations of 6 g/m(3) was applied on moisturized black pepper for 72 h, decreases in Salmonella counts of around 80% were observed. The counts of total aerobic mesophilic bacterium populations of the dried and moisturized black pepper were not affected by the fumigant treatment. The results of the postfumigation studies indicated that Salmonella Enteritidis was absent in the fumigated grains after drying and storage for 72 h, indicating a promising application for this technique. It was concluded that for Salmonella Enteritidis control, phosphine fumigation could be applied to black pepper grains before drying and the producers should rigidly follow good agricultural practices, mainly during the drying process, in order to avoid product recontamination. Additional work is needed to confirm the findings with more Salmonella serotypes and strains.

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

    SciTech Connect

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

    2013-03-07

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

  17. (Trimethylsilyl)phosphine as a Versatile Reagent for Syntheses of New 4-Sila- and 4-Phosphaphosphorinanes.

    PubMed

    Hackney, Michael L. J.; Schubert, David M.; Brandt, Paul F.; Haltiwanger, R. C.; Norman, Arlan D.

    1997-04-23

    (Trimethylsilyl)phosphine (Me(3)SiPH(2)) undergoes radical P-H bond addition to vinylphosphines and -silanes to form new 4-phospha- and 4-silaphosphorinanes [vinyl reagent]: [PhP(CH=CH(2))(2)], PhP(C(2)H(4))(2)PSiMe(3) diastereomers (9A/9B); [Et(2)NP(CH=CH(2))(2)], Et(2)NP(C(2)H(4))(2)PSiMe(3) (11); [Me(2)Si(CH=CH(2))(2)], Me(2)Si(C(2)H(4))(2)PSiMe(3) (14); [Si(CH=CH(2))(4)], (CH=CH(2))(2)Si(C(2)H(4))(2)PSiMe(3) (16) and [Me(3)SiP(C(2)H(4))(2)](2)Si (17). Reactions are accompanied by formation of only small quantities of the Markovnikov addition product phospholanes. Methanolysis of the new silylphosphines yields PhP(C(2)H(4))(2)PH diastereomers (10A/10B), Me(2)Si(C(2)H(4))PH (15), (CH=CH(2))(2)Si(C(2)H(4))(2)PH (18), and [HP(C(2)H(4))(2)](2)Si (19). Stepwise methanolysis of 11 yields the phosphorinanes Et(2)NP(C(2)H(4))(2)PH (12) and MeOP(C(2)H(4))(2)PH (13). Oxidation of 15 and 14 with O(2) or O(2)/H(2)O, respectively, yields the phosphine oxide Me(2)Si(C(2)H(4))(2)P(O)H (20) and the phosphinic acid Me(2)Si(C(2)H(4))(2)P(O)OH (21). New compounds were characterized by spectral ((31)P, (1)H, and (13)C NMR, IR, and MS) data. 21 was further characterized by a single-crystal X-ray analysis: monoclinic, P2(1)/c, a = 10.416(2) Å, b = 6.817(1) Å, c = 14.237(3) Å, beta = 106.32(2) degrees, Z = 4, V = 970.3(3) Å(3). The ring of 21 adopts a chair conformation with the P=O bond in an equatorial position. From spectral data, tentative isomeric and conformational structural assignments are made for the new phosphorinanes in solution.

  18. Unprecedented hybrid scorpionate/phosphine ligand able to be anchored to carbosilane dendrimers.

    PubMed

    Casado, Miguel A; Hack, Verena; Camerano, José A; Ciriano, Miguel A; Tejel, Cristina; Oro, Luis A

    2005-12-12

    The synthesis of a novel hybrid pyrazolate/phosphine anionic ligand [CH2=CHCH2B(CH2PPh2)(pz)2]- is described. Coordination of this ligand to metals in a fac tridentate fashion occurs in the complexes [CH2=CHCH2B(CH2PPh2)(pz)2M(cod)], prepared by reactions of the lithium salt of the ligand with [M(mu-Cl)(cod)]2 (M=Rh, Ir). They are pentacoordinated, with the rhodium complex showing a distorted trigonal-bipyramidal structure in the solid state, as determined by X-ray diffraction methods. Furthermore, the ligand has been linked to the periphery of a carbosilane dendrimer, resulting in the polyanionic dendrimer [Li(TMED)]4[Si{(CH2)3SiMe2(CH2)3B(CH2PPh2)(pz)2}4], which leads further to the corresponding metallodendrimer with four rhodium atoms.

  19. Chlorido[tris­(3-fluoro­phen­yl)phosphine]gold(I)

    PubMed Central

    Shawkataly, Omar bin; Tariq, Abu; Ghani, Syed Sauban; Yeap, Chin Sing; Fun, Hoong-Kun

    2010-01-01

    In the title gold complex, [AuCl(C18H12F3P)], the P—Au—Cl unit is nearly linear, with an angle of 178.13 (5)°. The three phosphine-substituted benzene rings make dihedral angles of 77.7 (3), 84.4 (3) and 77.4 (3)° with each other. Two of the three F atoms are disordered over two positions, with refined site occupancies of 0.591 (11):0.409 (11) and 0.730 (12):0.270 (12). In the crystal structure, mol­ecules are linked into a three-dimensional network by inter­molecular C—H⋯Cl and C—H⋯F hydrogen bonds. PMID:21587375

  20. 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.

  1. 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

  2. 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.

  3. 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.

  4. 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.

  5. Sulfone and phosphinic acid analogs of decaprenolphosphoarabinose as potential anti-tuberculosis agents.

    PubMed

    Centrone, Charla A; Lowary, Todd L

    2004-11-01

    Mycobacteria biosynthesize a cell wall structure that is rich in polysaccharides containing arabinofuranose residues. The source of these arabinofuranose residues is decaprenolphosphoarabinose (1), the donor substrate for mycobacterial arabinosyltransferases. We have previously demonstrated that an analog of 1, C-phosphonate 7, prevented the growth of mycobacteria and this compound is currently undergoing testing for efficacy in tuberculosis-infected mice. We describe here the synthesis and testing of additional analogs of 1 that contain either a sulfone (8-14) or phosphinic acid (15-19) moiety in place of the phosphodiester functionality. Screening of these compounds in vitro against Mycobacterium tuberculosis strain H(37)Rv revealed that while some of these compounds possessed low to modest activity, none was as potent as 7.

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

    NASA Astrophysics Data System (ADS)

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

    2015-10-01

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

  7. Phosphine-Catalyzed Enantioselective Intramolecular [3+2] Annulations To Generate Fused Ring Systems

    PubMed Central

    2015-01-01

    Substantial progress has been described in the development of asymmetric variants of the phosphine-catalyzed intermolecular [3+2] annulation of allenes with alkenes; however, there have not been corresponding advances for the intramolecular process, which can generate a higher level of complexity (an additional ring and stereocenter(s)). In this study, we describe the application of chiral phosphepine catalysts to address this challenge, thereby providing access to useful scaffolds that are found in bioactive compounds, including diquinane and quinolin-2-one derivatives, with very good stereoselectivity. The products of the [3+2] annulation can be readily transformed into structures that are even more stereochemically rich. Mechanistic studies are consistent with β addition of the phosphepine to the allene being the turnover-limiting step of the catalytic cycle, followed by a concerted [3+2] cycloaddition to the pendant olefin. PMID:25815702

  8. Extraction of phenols from water with tri-octyl phosphine oxide

    SciTech Connect

    MacGlashan, J.D.

    1982-03-01

    Tri-octyl phosphine oxide (TOPO) was examined as an extractant for removing phenol; the dihydric phenols catechol, resorcinol, and hydroquinone; and the trihydric phenols pyrogallol, phloroglucinol, and 1,2,4-benzenetriol from water. Distribution coefficients were measured and results modelled for extractions with different diluents, solvent compositions, temperatures, and extractant-to-solute stoichiometric ratios. Modelling of the results indicates that the extraction mechanism is complicated, with the diluent probably playing an important role. The most effective diluents are those that have some electron-donating ability and are thus able to solvate the solute-TOPO complex, without competing with the solute for the phosphoryl oxygen on TOPO. The distribution coefficients decrease with increasing temperature, and show a linear dependence when plotted as ln(K/sub D/) vs. l/T.

  9. Phosphinic acid functionalized polyazacycloalkane chelators for radiodiagnostics and radiotherapeutics: unique characteristics and applications.

    PubMed

    Notni, Johannes; Šimeček, Jakub; Wester, Hans-Jürgen

    2014-06-01

    Given the wide application of positron emission tomography (PET), positron-emitting metal radionuclides have received much attention recently. Of these, gallium-68 has become particularly popular, as it is the only PET nuclide commercially available from radionuclide generators, therefore allowing local production of PET radiotracers independent of an on-site cyclotron. Hence, interest in optimized bifunctional chelators for the elaboration of (68) Ga-labeled bioconjugates has been rekindled as well, resulting in the development of improved triazacyclononane-triphosphinate (TRAP) ligand structures. The most remarkable features of these ligands are unparalleled selectivity for Ga(III) , rapid Ga(III) complexation kinetics, extraordinarily high thermodynamic stability, and kinetic inertness of the respective Ga(III) chelates. As a result, TRAP chelators exhibit very favorable (68) Ga-labeling properties. Based on the scaffolds NOPO (1,4,7-triazacyclononane-1,4-bis[methylene(hydroxymethyl)phosphinic acid]-7-[methylene(2-carboxyethyl)phosphinic acid]) and TRAP-Pr, tailored for convenient preparation of (68) Ga-labeled monomeric and multimeric bioconjugates, a variety of novel (68) Ga radiopharmaceuticals have been synthesized. These include bisphosphonates, somatostatin receptor ligands, prostate-specific membrane antigen (PSMA)-targeting peptides, and cyclic RGD pentapeptides, for in vivo PET imaging of bone, neuroendocrine tumors, prostate cancer, and integrin expression, respectively. Furthermore, TRAP-based (68) Ga-labeled gadolinium(III) complexes have been proposed as bimodal probes for PET/MRI, and a cyclen-based analogue of TRAP-Pr has been suggested for the elaboration of targeted radiotherapeutics comprising radiolanthanide ions. Thus, polyazacycloalkane-based polyphosphinic acid chelators are a powerful toolbox for pharmaceutical research, particularly for the development of (68) Ga radiopharmaceuticals. PMID:24700633

  10. Distribution characteristics of matrix-bound phosphine along the coast of China and possible environmental controls.

    PubMed

    Feng, Zhihua; Song, Xiuxian; Yu, Zhiming

    2008-09-01

    Matrix-bound phosphine (MBP) concentrations in surface sediments collected from 37 stations along the coast of China in 2006 are reported. MBP was found in all samples and the average concentration was 6.30ngkg(-1)dry weight (dw). The distribution of MBP showed certain spatial variation characteristics with high MBP concentrations at stations near to the coast. The average concentrations of MBP in the northern Yellow Sea (NYS), the southern Yellow Sea (SYS), the northern area of East China Sea (NECS), the southern area of East China Sea (SECS), and South China Sea (SCS) were 5.57+/-3.78, 3.78+/-2.81, 5.27+/-3.07, 5.48+/-4.05 and 13.52+/-7.86ngkg(-1)dw, respectively. The correlations between MBP and influencing factors, such as the sedimentary environmental characteristics (sediment type, the grain size, contents of phosphorous, organic matters and redox potential) and the aquatic environmental characteristics (temperature, salinity, depth and hydrodynamics) were studied. The results indicated that MBP was strongly influenced by various factors, such as total phosphorus (TP), organic phosphorus (OP), organic carbon (OC), the grain size and hydrodynamics, all of which not only offered reasonable interpretations for the distribution characteristics of MBP but also provided evidence to support the viewpoint that phosphine originated from OP decomposition. This work is the first comprehensive study of the distribution of MBP along the coast of China and its relationships with environmental factors which will lead to a better understanding of the phosphorus (P) biogeochemical cycle in the sea.

  11. 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...

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

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

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

  14. Diphen­yl[2-(2-pyridylamino­meth­yl)phen­yl]phosphine oxide

    PubMed Central

    Hernández-Ortega, Simón; Cuenu Cabeza, Fernando; Cabrera-Ortiz, Armando

    2010-01-01

    The title compound, C24H21N2OP, was obtained by reacting 2-amino­pyridine and 2-(diphenyl­phosphin­yl)benzaldehyde in ethanol. It crystallizes with two crystallographically independent mol­ecules in the asymmetric unit. The amino­pyridine units and the benzene ring bonded to the phosphine oxide P atom form dihedral angles of 88.58 (7) and 82.47 (9)° in the two mol­ecules. The crystal structure displays strong N—H⋯O and weak C—H⋯O hydrogen bonds along the b axis and C—H⋯π aromatic intra- and inter­molecular inter­actions. PMID:21579222

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

    PubMed

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

    2015-11-16

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

  16. The phosphine oxides Cyanex 921 and Cyanex 923 as carriers for facilitated transport of chromium (VI)-chloride aqueous solutions.

    PubMed

    Alguacil, Francisco José; López-Delgado, Aurora; Alonso, Manuel; Sastre, Ana Maria

    2004-11-01

    The behaviour of the phosphine oxides Cyanex 921 and Cyanex 923 in the facilitated transport of chromium (VI) from chloride solutions is described. Transport is studied as a function of several variables such as stirring speeds of the aqueous phases, membrane phase diluent, hydrochloric acid concentration in the source phase and chromium and carrier concentrations. The separation of chromium (VI) from other metals presented in the source phase as well as the behaviour of phosphine oxides with respect to other neutral organophosphorous derivatives (tri-n-butylphosphate (TBP) and dibutyl butylphosphonate (DBBP)) are also investigated. Moreover, by using hydrazine sulphate in the receiving phase, Cr(VI) is immediately reduced to the less toxic Cr(III).

  17. Gene interactions constrain the course of evolution of phosphine resistance in the lesser grain borer, Rhyzopertha dominica.

    PubMed

    Schlipalius, D I; Chen, W; Collins, P J; Nguyen, T; Reilly, P E B; Ebert, P R

    2008-05-01

    Phosphine, a widely used fumigant for the protection of stored grain from insect pests, kills organisms indirectly by inducing oxidative stress. High levels of heritable resistance to phosphine in the insect pest of stored grain, Rhyzopertha dominica have been detected in Asia, Australia and South America. In order to understand the evolution of phosphine resistance and to isolate the responsible genes, we have undertaken genetic linkage analysis of fully sensitive (QRD14), moderately resistant (QRD369) and highly resistant (QRD569) strains of R. dominica collected in Australia. We previously determined that two loci, rph1 and rph2, confer high-level resistance on strain QRD569, which was collected in 1997. We have now confirmed that rph1 is responsible for the moderate resistance of strain QRD369, which was collected in 1990, and is shared with a highly resistant strain from the same geographical region, QRD569. In contrast, rph2 by itself confers only very weak resistance, either as a heterozygote or as a homozygote and was not discovered in the field until weak resistance (probably due to rph1) had become ubiquitous. Thus, high-level resistance against phosphine has evolved via stepwise acquisition of resistance alleles, first at rph1 and thereafter at rph2. The semi-dominance of rph2 together with the synergistic interaction between rph1 and rph2 would have led to rapid selection for homozygosity. A lack of visible fitness cost associated with alleles at either locus suggests that the resistance phenotype will persist in the field.

  18. 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

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

    PubMed

    Tin, Sergey; Fanjul, Tamara; Clarke, Matthew L

    2015-01-01

    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

  20. Diagnostic molecular markers for phosphine resistance in U.S. populations of Tribolium castaneum and Rhyzopertha dominica.

    PubMed

    Chen, Zhaorigetu; Schlipalius, David; Opit, George; Subramanyam, Bhadriraju; Phillips, Thomas W

    2015-01-01

    Stored product beetles that are resistant to the fumigant pesticide phosphine (hydrogen phosphide) gas have been reported for more than 40 years in many places worldwide. Traditionally, determination of phosphine resistance in stored product beetles is based on a discriminating dose bioassay that can take up to two weeks to evaluate. We developed a diagnostic cleaved amplified polymorphic sequence method, CAPS, to detect individuals with alleles for strong resistance to phosphine in populations of the red flour beetle, Tribolium castaneum, and the lesser grain borer, Rhyzopertha dominica, according to a single nucleotide mutation in the dihydrolipoamide dehydrogenase (DLD) gene. We initially isolated and sequenced the DLD genes from susceptible and strongly resistant populations of both species. The corresponding amino acid sequences were then deduced. A single amino acid mutation in DLD in populations of T. castaneum and R. dominica with strong resistance was identified as P45S in T. castaneum and P49S in R. dominica, both collected from northern Oklahoma, USA. PCR products containing these mutations were digested by the restriction enzymes MboI and BstNI, which revealed presence or absence, respectively of the resistant (R) allele and allowed inference of genotypes with that allele. Seven populations of T. castaneum from Kansas were subjected to discriminating dose bioassays for the weak and strong resistance phenotypes. Application of CAPS to these seven populations confirmed the R allele was in high frequency in the strongly resistant populations, and was absent or at a lower frequency in populations with weak resistance, which suggests that these populations with a low frequency of the R allele have the potential for selection of the strong resistance phenotype. CAPS markers for strong phosphine resistance will help to detect and confirm resistant beetles and can facilitate resistance management actions against a given pest population.

  1. The rph2 gene is responsible for high level resistance to phosphine in independent field strains of Rhyzopertha dominica.

    PubMed

    Mau, Yosep S; Collins, Patrick J; Daglish, Gregory J; Nayak, Manoj K; Ebert, Paul R

    2012-01-01

    The lesser grain borer Rhyzopertha dominica (F.) is one of the most destructive insect pests of stored grain. This pest has been controlled successfully by fumigation with phosphine for the last several decades, though strong resistance to phosphine in many countries has raised concern about the long term usefulness of this control method. Previous genetic analysis of strongly resistant (SR) R. dominica from three widely geographically dispersed regions of Australia, Queensland (SR(QLD)), New South Wales (SR(NSW)) and South Australia (SR(SA)), revealed a resistance allele in the rph1 gene in all three strains. The present study confirms that the rph1 gene contributes to resistance in a fourth strongly resistant strain, SR2(QLD), also from Queensland. The previously described rph2 gene, which interacts synergistically with rph1 gene, confers strong resistance on SR(QLD) and SR(NSW). We now provide strong circumstantial evidence that weak alleles of rph2, together with rph1, contribute to the strong resistance phenotypes of SR(SA) and SR2(QLD). To test the notion that rph1 and rph2 are solely responsible for the strong resistance phenotype of all resistant R. dominica, we created a strain derived by hybridising the four strongly resistant lines. Following repeated selection for survival at extreme rates of phosphine exposure, we found only slightly enhanced resistance. This suggests that a single sequence of genetic changes was responsible for the development of resistance in these insects.

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

    PubMed

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

    2016-05-21

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

  3. 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.

  4. 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

  5. On the origin of reversible hydrogen activation by phosphine-boranes.

    PubMed

    Rajeev, Ramanan; Sunoj, Raghavan B

    2009-11-23

    Mechanistic insights into the factors responsible for the reversible hydrogen-activation ability exhibited by an aryl phosphine-borane system ((CH(3))(2)P-C(6)F(4)-B(CF(3))(2)) are presented. A detailed evaluation of the energies of various intermediates, generated by the addition of molecular hydrogen, and their interconverting barriers have been carried out using ab initio and DFT methods. Several rearrangement possibilities of the H(2)-phosphino-borane adduct have been investigated so as to unravel the lower energy pathways that convert the initial adduct to a series of other intermediates. The initial adduct formed by the heterolytic addition of a molecular hydrogen across the C-B bond is identified to undergo a series of rearrangement reactions until it terminates at the C-P end of the molecule. Among the possible 1,n-migrations (for which n=1-5), 1,2-proton migrations are found to possess lower energy transition states, whereas 1,2-hydride (in a zwitterionic intermediate) and 1,4-proton-coupled electron transfers exhibited much higher energy transition states. The minimum energy pathway for the transfer of a proton and hydride from the C-B bond to the C-P bond is found to involve a cascade of 1,2-proton transfers followed by a 1,2-hydride migration and finally a 1,4-proton-coupled electron transfer. The higher energy pathways identified for the hydride transfer suggest the possibility of a cascade of reversible proton migrations from a thermodynamically stable intermediate (M(a)). Possible uptake of two hydrogen molecules by the phosphine-borane system is additionally considered in the present study, in which relatively higher barriers than those with one molecule of hydrogen are observed. The computed thermodynamic parameters are found to be in accordance with the experimental observations, in which the uptake and storage of molecular hydrogen are carried out at lower temperatures whereas the liberation demands elevated temperatures.

  6. Accessible gold clusters using calix[4]arene N-heterocyclic carbene and phosphine ligands.

    PubMed

    Nigra, Michael M; Yeh, Alexander J; Okrut, Alexander; DiPasquale, Antonio G; Yeh, Sheila W; Solovyov, Andrew; Katz, Alexander

    2013-09-21

    We investigate the synthesis of accessible calix[4]arene-bound gold clusters consisting of open "coordinatively unsaturated" active sites, using a comparative approach that relies on calix[4]arene ligands with various upper- and lower-rim substituents. In contrast with a reported Au(I)-tert-butyl-calixarene phosphine complex, which exhibits a single cone conformer in solution, the H upper-rim analog exhibits multiple conformers in solution. This contrasts with observations of the tert-butyl upper-rim analog, which exhibits a single cone conformer in solution under similar conditions. In the solid state, as determined by single-crystal X-ray diffraction, both H and tert-butyl upper-rim analogs exhibit exclusively cone conformer. A detailed structural analysis of these two solid-state structures highlights a CH-π interaction involving a methoxy lower-rim substituent and phenyl substituent on P as the key feature that enforces a tight configuration of Au(I) atoms on the same side of the calix[4]arene lower-rim plane. We hypothesize that such a configuration promotes chelation of the ligand to a gold surface and facilitates the synthesis of small Au11-sized clusters after reduction of both complexes. The new cluster, like the one reported with the tert-butyl analog, has an extraordinary 25% of surface atoms that are open and accessible to a 2-NT (2-naphthalenethiol) probe in solution. We also investigated the effect of calix[4]arene lower-rim substituents that coordinate to the metal, by using N-heterocyclic carbene (NHC) functional groups rather than phosphines. Four small (<1.6 nm diameter) calix[4]arene NHC-bound gold clusters were synthesized, including three using novel calix[4]arene NHC ligands. The smallest calix[4]arene NHC-bound Au cluster consisted of a 1.2 nm gold core, and its number density of accessible and open surface sites was measured. This required development of a new titration method for open sites on gold clusters, using a SAMSA fluorescein dye

  7. Photophysical and computational investigations of bis(phosphine) organoplatinum(II) metallacycles.

    PubMed

    Pollock, J Bryant; Cook, Timothy R; Stang, Peter J

    2012-06-27

    A series of endohedral and exohedral amine-functionalized ligands were synthesized and used in the construction of supramolecular D(2h) rhomboids and a D(6h) hexagon. These supramolecular polygons were obtained via self-assembly of 120° dipyridyl donors with 180° or 120° diplatinum precursors when combined in 1:1 ratios. Steady-state absorption and emission spectra were collected for each ligand and metallacycle. Density functional theory (DFT) and time-dependent DFT calculations were employed to probe the nature of the observed optical transitions for the rhomboids. The emissive properties of these bis(phosphine) organoplatinum metallacycles arise from ligand-centered transitions involving π-type molecular orbitals with modest contributions from metal-based atomic orbitals. The D(2h) rhomboid self-assembled from 2,6-bis(4-pyridylethynyl)aniline and a 60° organoplatinum(II) acceptor has a low-energy excited state in the visible region and emits above 500 nm, properties which greatly differ from those of the parent 2,6-bis(4-pyridylethynyl)aniline ligand. PMID:22691193

  8. Determination of phosphine in plant materials: method optimization and validation in interlaboratory comparison tests.

    PubMed

    Amrein, Thomas M; Ringier, Lara; Amstein, Nathalie; Clerc, Laurence; Bernauer, Sabine; Baumgartner, Thomas; Roux, Bernard; Stebler, Thomas; Niederer, Markus

    2014-03-01

    The optimization and validation of a method for the determination of phosphine in plant materials are described. The method is based on headspace sampling over the sample heated in 5% sulfuric acid. Critical factors such as sample amount, equilibration conditions, method of quantitation, and matrix effects are discussed, and validation data are presented. Grinding of coarse samples does not lead to lower results and is a prerequisite for standard addition experiments, which present the most reliable approach for quantitation because of notable matrix effects. Two interlaboratory comparisons showed that results varied considerably and that an uncertainty of measurement of about 50% has to be assessed. Flame photometric and mass spectrometric detection gave similar results. The proposed method is well reproducible within one laboratory, and results from the authors' laboratories using different injection and detection techniques are very close to each other. The considerable variation in the interlaboratory comparison shows that this analysis is still challenging in practice and further proficiency testing is needed. PMID:24564743

  9. 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).

  10. 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.

  11. Luminescent heterometallic gold-copper alkynyl complexes stabilized by tridentate phosphine.

    PubMed

    Shakirova, Julia R; Grachova, Elena V; Gurzhiy, Vladislav V; Koshevoy, Igor O; Melnikov, Alexei S; Sizova, Olga V; Tunik, Sergey P; Laguna, Antonio

    2012-03-14

    The reactions between trinuclear gold complex tppmAu(3)Cl(3) (tppm = tris(diphenylphosphino)methane), arylacetylenes HC(2)C(6)H(4)X and Cu(+) under basic conditions result in formation of the heterometallic complexes [tppm(AuC(2)C(6)H(4)X)(3)Cu](+), X = H (1), COOMe (2), CN (3), OMe (4), NH(2) (5). These compounds belong to one structural motif and consist of the heterometallic {(AuC(2)C(6)H(4)X)(3)Cu} core stabilized by the tridentate phosphine. Compounds 1-5 were characterized by polynuclear NMR and IR spectroscopy, ESI-MS and single-crystal X-ray analysis. Luminescence properties of these complexes have been studied and revealed a substantial red shift of the emission maxima with the increase in the electron donicity of the alkynyl ligands substituents in the 550-680 nm range. The theoretical calculations of the electronic structures showed that variations of the substituents on the alkynyl ligands display very little effect on the molecular structural parameters but show appreciable influence on the orbital energies and luminescence characteristics of the compounds under study. PMID:22266767

  12. Lanthanide(II) complexes of a phosphine-borane-stabilised carbanion.

    PubMed

    Izod, Keith; Clegg, William; Harrington, Ross W

    2010-08-01

    The reaction between two equivalents of the potassium salt [(Me(3)Si)(2){Me(2)P(BH(3))}C]K (4) and SmI(2)(THF)(2) in refluxing THF yields the dialkylsamarium(II) compounds [(Me(3)Si)(2){Me(2)P(BH(3))}C](2)Sm(THF) (5a) or [(Me(3)Si)(2){Me(2)P(BH(3))}C](2)Sm(THF)(3) (5b), depending on the crystallisation conditions, in good yield as air- and moisture-sensitive crystalline solids. X-ray crystallography shows that, whereas both alkyl ligands chelate the samarium(II) ion in 5a, in 5b one alkyl ligand chelates the metal centre and one binds the metal only through its borane hydrogen atoms. The reaction between YbI(2) and two equivalents of 4 in refluxing benzene yields the solvent-free dialkylytterbium(II) compound [(Me(3)Si)(2){Me(2)P(BH(3))}C](2)Yb (8). In contrast to 5a and 5b, compound 8 reacts rapidly with THF to give the free phosphine-borane (Me(3)Si)(2){Me(2)P(BH(3))}CH as the only identifiable product. PMID:20480086

  13. Phosphine-ligated dinitrosyl iron complexes for redox-controlled NO release.

    PubMed

    Wittkamp, F; Nagel, C; Lauterjung, P; Mallick, B; Schatzschneider, U; Apfel, U-P

    2016-06-21

    Here we present the syntheses and structural, spectroscopic, as well as electrochemical properties of four dinitrosyl iron complexes (DNICs) based on silicon- and carbon-derived di- and tripodal phosphines. Whereas CH3C(CH2PPh2)3 and Ph2Si(CH2PPh2)2 coordinate iron in a η(2) - binding mode, CH3Si(CH2PPh2)3 undergoes cleavage of one Si-C bond to afford [Fe(NO)2(P(CH3)Ph2)2] at elevated temperatures. The complexes were characterized by IR spectroelectrochemistry as well as UV-vis measurements. The oxidized {Fe(NO)2}(9) compounds were obtained by oxidation with (NH4)2[Ce(NO3)6] and their properties evaluated with Mössbauer and IR spectroscopy. Stability experiments on the complexes suggest that they are capable of releasing their NO-ligands in the oxidized {Fe(NO)2}(9) but not in the reduced {Fe(NO)2}(10) form. A detailed DFT analysis is provided in order to understand the electronic configurations and the complexes' ability to release NO. PMID:27241282

  14. Phosphine-ligated dinitrosyl iron complexes for redox-controlled NO release.

    PubMed

    Wittkamp, F; Nagel, C; Lauterjung, P; Mallick, B; Schatzschneider, U; Apfel, U-P

    2016-06-21

    Here we present the syntheses and structural, spectroscopic, as well as electrochemical properties of four dinitrosyl iron complexes (DNICs) based on silicon- and carbon-derived di- and tripodal phosphines. Whereas CH3C(CH2PPh2)3 and Ph2Si(CH2PPh2)2 coordinate iron in a η(2) - binding mode, CH3Si(CH2PPh2)3 undergoes cleavage of one Si-C bond to afford [Fe(NO)2(P(CH3)Ph2)2] at elevated temperatures. The complexes were characterized by IR spectroelectrochemistry as well as UV-vis measurements. The oxidized {Fe(NO)2}(9) compounds were obtained by oxidation with (NH4)2[Ce(NO3)6] and their properties evaluated with Mössbauer and IR spectroscopy. Stability experiments on the complexes suggest that they are capable of releasing their NO-ligands in the oxidized {Fe(NO)2}(9) but not in the reduced {Fe(NO)2}(10) form. A detailed DFT analysis is provided in order to understand the electronic configurations and the complexes' ability to release NO.

  15. 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 Águila-Sánchez, Miguel A; Navarro, Yolanda; García López, Jesús; Guedes, Guilherme P; López 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.

  16. 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 Carbó-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 σ-donor and π-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

  17. Effectiveness of Sulfuryl Fluoride Fumigation for the Control of Phosphine-Resistant Grain Insects Infesting Stored Wheat.

    PubMed

    Opit, George P; Thoms, Ellen; Phillips, Thomas W; Payton, Mark E

    2016-04-01

    A field experiment was conducted in eight 13.6-MT steel bins containing 6.8 MT each of wheat to assess efficacy of sulfuryl fluoride or SF fumigant to control phosphine-resistant and susceptible Rhyzopertha dominica (F.) and Tribolium castaneum (Herbst). Approximately 400 adults of each type of beetle were added to each bin. Additionally, muslin bags containing immature stages and adults, with their respective diets, were also placed in bins. Four bins were fumigated with SF and others were untreated control bins. The SF dosages in treated bins ranged from 1,196–1,467 mg-h/liter. Mortality of adults in each bag was assessed 5 d postfumigation; diet minus adults was incubated in a jar, and number of adults counted after 8 wk. No significant change occurred in number of insect-damaged kernels in SF-treated bins. In trier samples from SF-treated bins, R. dominica numbers declined from 24 prefumigation to 0 at 3- and 6-wk postfumigation; T. castaneum numbers were unchanged. In WBII traps from SF-treated bins, numbers R. dominica and T. castaneum declined from 25 and 33, respectively, prefumigation to 0 or near 0 at 3- and 6-wk postfumigation. Mortalities of resistant and susceptible adult R. dominica, and adult and large larvae of T. castaneum in SF-treated bags was 100%. For all four types of beetles, adult numbers in jars associated with SF-treated bins were 0 or near 0. Results show SF is effective against all life stages of phosphine-resistant R. dominica and T. castaneum, and can be used for phosphine resistance management.

  18. 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.

  19. 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.

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

    PubMed

    Máté, Gábor; Šimeček, Jakub; Pniok, Miroslav; Kertész, István; Notni, Johannes; Wester, Hans-Jürgen; Galuska, László; Hermann, Petr

    2015-07-21

    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.

  1. Mechanism, regioselectivity, and the kinetics of phosphine-catalyzed [3+2] cycloaddition reactions of allenoates and electron-deficient alkenes.

    PubMed

    Liang, Yong; Liu, Song; Xia, Yuanzhi; Li, Yahong; Yu, Zhi-Xiang

    2008-01-01

    With the aid of computations and experiments, the detailed mechanism of the phosphine-catalyzed [3+2] cycloaddition reactions of allenoates and electron-deficient alkenes has been investigated. It was found that this reaction includes four consecutive processes: 1) In situ generation of a 1,3-dipole from allenoate and phosphine, 2) stepwise [3+2] cycloaddition, 3) a water-catalyzed [1,2]-hydrogen shift, and 4) elimination of the phosphine catalyst. In situ generation of the 1,3-dipole is key to all nucleophilic phosphine-catalyzed reactions. Through a kinetic study we have shown that the generation of the 1,3-dipole is the rate-determining step of the phosphine-catalyzed [3+2] cycloaddition reaction of allenoates and electron-deficient alkenes. DFT calculations and FMO analysis revealed that an electron-withdrawing group is required in the allene to ensure the generation of the 1,3-dipole kinetically and thermodynamically. Atoms-in-molecules (AIM) theory was used to analyze the stability of the 1,3-dipole. The regioselectivity of the [3+2] cycloaddition can be rationalized very well by FMO and AIM theories. Isotopic labeling experiments combined with DFT calculations showed that the commonly accepted intramolecular [1,2]-proton shift should be corrected to a water-catalyzed [1,2]-proton shift. Additional isotopic labeling experiments of the hetero-[3+2] cycloaddition of allenoates and electron-deficient imines further support this finding. This investigation has also been extended to the study of the phosphine-catalyzed [3+2] cycloaddition reaction of alkynoates as the three-carbon synthon, which showed that the generation of the 1,3-dipole in this reaction also occurs by a water-catalyzed process.

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

    PubMed

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

    2016-05-01

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

  3. Borane-protected phosphines are redox-active radioprotective agents for endothelial cells.

    PubMed

    Crowe, Megan E; Lieven, Christopher J; Thompson, Alex F; Sheibani, Nader; Levin, Leonard A

    2015-12-01

    Exposure to radiation can damage endothelial cells in the irradiated area via the production of reactive oxygen species. We synthesized phosphine-borane complexes that reduce disulfide bonds and had previously been shown to interfere with redox-mediated signaling of cell death. We hypothesized that this class of drugs could interfere with the downstream effects of oxidative stress after irradiation and rescue endothelial cells from radiation damage. Cultured bovine aortic endothelial cells were plated for clonogenic assay prior to exposure to varying doses of irradiation from a (137)Cs irradiator and treated with various concentrations of bis(3-propionic acid methyl ester)phenylphosphine borane complex (PB1) at different time points. The clone-forming ability of the irradiated cells was assessed seven days after irradiation. We compared the radioprotective effects of PB1 with the aminothiol radioprotectant WR1065 and known superoxide scavengers. PB1 significantly protected bovine aortic endothelial cells from radiation damage, particularly when treated both before and after radiation. The radioprotection with 1 µM PB1 corresponded to a dose-reduction factor of 1.24. Radioprotection by PB1 was comparable to the aminothiol WR1065, but was significantly less toxic and required much lower concentrations of drug (1 µM vs. 4 mM, respectively). Superoxide scavengers were not radioprotective in this paradigm, indicating the mechanisms for both loss of clonogenicity and PB1 radioprotection are independent of superoxide signaling. These data demonstrate that PB1 is an effective redox-active radioprotectant for endothelial cells in vitro, and is radioprotective at a concentration approximately 4 orders of magnitude lower than the aminothiol WR1065 with less toxicity. PMID:26188467

  4. Preparation of novel alkylated ruthenium {alpha}-diimine complexes: Reactivity toward carbon monoxide and phosphines

    SciTech Connect

    Kraakman, M.J.A.; Vrieze, K.; Kooijman, H.; Spek, A.L.

    1992-11-01

    Ru{sub 2}(CO){sub 5}({sup i}Pr-DAB) (1) reacts with MeI at room temperature to give Ru{sub 2}(Me)(I)(CO){sub 4}({sup i}Pr-DAB) (2a), and a single-crystal X-ray structure determination of 2a has been obtained. Treatment of 2a with CO leads to substitution of the iodide bridge and the two coordinated imine bonds with the formation of Ru(Me)(I)(CO{sub 2})({sup i}Pr-DAB) (3a) and Ru(CO){sub 5}. This reaction, which is reversible, provides a new synthetic route for the preparation of monomeric methylated {alpha}-diimine complexes. Several other reaction routes for the formation of the complexes Ru(X)(Y)(CO){sub 2}({alpha}-diimine) (X = Me, Y = I, {alpha}-diimine Y = I, {alpha}-diimine = {sup i}Pr-Pyca (3b); X = Y = I, {alpha}-diimine = {sup i}Pr-DAB (3c); X = Y = I, {alpha}-diimine = {sup i}Pr-pyca (3d); X = Cl, Y = benzyl, {alpha}-diimine = {sup i}Pr-DAB (3e)) are presented. Treatment of 2a with phosphines leads to substitution of only one coordinated imine bond, with the formation of Ru{sub 2}(Me)(I)(CO){sub 4}(PR{sub 3})({sup i}Pr-DAB) (PR{sub 3} = PPh{sub 3} (4a), PMe{sub 2}Ph (4b), P(OMe){sub 3} (4c)). 62 refs., 4 figs., 13 tabs.

  5. 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.

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

    PubMed

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

    2016-05-01

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

  7. 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

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

    PubMed

    Molter, Anja; Rust, Jörg; 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

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

    PubMed

    Molter, Anja; Rust, Jörg; 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.

  10. 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).

  11. 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.

  12. 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.

  13. 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

  14. Triphenyl phosphine adducts of platinum(IV) and palladium(II) dithiocarbamates complexes: a spectral and in vitro study

    NASA Astrophysics Data System (ADS)

    Manav, N.; Mishra, A. K.; Kaushik, N. K.

    2004-11-01

    Triphenyl phosphine adducts of dithiocarbamate complexes of platinum(IV) and palladium(II) of the type [Pt(L) 2PPh 3Cl 2] and [Pd(L) 2PPh 3] [L: morpholine dithiocarbamate (L 1), aniline dithiocarbamate (L 2) and N-(methyl, cyclohexyl) dithiocarbamate (L 3)] were prepared and characterized by elemental analysis, electronic, IR, 1H NMR and 13C NMR spectral studies. Thermal studies of the complexes were carried out. In vitro antitumor activity has been screened towards human adenocarcinoma cell lines and showed significant inhibition even at very low concentration.

  15. (2,4,6-Trimethyl­phen­yl)boronic acid–triphenyl­phosphine oxide (1/1)

    PubMed Central

    Roşca, Sorin; Olaru, Marian; Raţ, Ciprian I.

    2012-01-01

    In the crystal structure of the title compound, C9H13BO2·C18H15OP, there are O—H⋯O hydrogen bonds between the O atom of triphenyl­phosphine oxide and one hy­droxy group of the boronic acid. Boronic acid mol­ecules form inversion-related hydrogen-bonded dimers in an R 2 2(8) motif. The structure is consolidated by inter­molecular C—H⋯O bonds and C—H⋯π inter­actions. PMID:22259536

  16. Synthesis and structural studies of some new rhenium phosphine heptahydride complexes. Evidence for classical structures in solution

    SciTech Connect

    Luo, Xiaoliang; Crabtree, R.H. )

    1990-06-06

    A series of new rhenium phosphine heptahydride complexes ReH{sub 7}L{sub 2} (L{sub 2} = a chelating bidentate phosphine) have been synthesized and characterized by IR and {sup 1}H, and {sup 31}P, and {sup 13}C NMR spectroscopy. The hydride resonances of ReH{sub 7}(dppf) (1, dppf = 1,1{prime}-bis(diphenylphosphino)ferrocene), ReH{sub 7}(dppb) (2, dppb = 1,4-bis(diphenylphosphino)butane), and ReH{sub 7}((+)-diop) (3, (+)-diop = (4S,5S)-4,5-bis((diphenylphosphino)methyl)-2,2-dimethyl-1,3-dioxolane) undergo decoalescence upon cooling. The low-temperature hydride patterns suggest classical 9-coordinate tricapped trigonal prismatic structures. Consistent with the classical structures, {sup 1}H NMR spectra of deuterated ReH{sub 7}L{sub 2} complexes show very small and temperature-independent upfield isotope shifts in the hydride region and no change in {sup 2}J{sub HP}.

  17. Sulfonated poly(arylene ether sulfone)s with phosphine oxide moieties: a promising material for proton exchange membranes.

    PubMed

    Fu, Lingchao; Xiao, Guyu; Yan, Deyue

    2010-06-01

    Sulfonated poly(arylene ether sulfone)s with phosphine oxide moieties (sPESPO) were achieved by polycondensation of bis(4-hydroxyphenyl)phenylphosphine oxide with 3,3'-disulfonate-4,4'-difluorodiphenyl sulfone (SFDPS) and 4-fluorophenyl sulfone (FPSF). Sulfonated poly(arylene ether sulfone)s (sPES) were also synthesized by polymerization of 4,4'-sulfonyldiphenol with SFDPS and FPSF for comparison. The comparative study demonstrates that the sPESPO ionomers exhibit strong intermolecular interactions and high oxidative stability because of the phosphine oxide groups. Furthermore, the sPESPO membrane and the sPES membrane with an equal ion exchange capacity show much different nanophase separation morphology. As a result, the former shows better properties than the latter. The sPESPO membranes exhibit excellent overall properties. For instance, the sPESPO membrane, with a disulfonation degree of 45%, exhibits high thermal and oxidative stability. Moreover, it shows a water uptake of 30.8% and a swelling ratio of 15.8% as well as a proton conductivity of 0.087 S/cm at 80 degrees C.

  18. 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.

  19. Phosphine Oxide-Sc(OTf)3 Catalyzed Highly Regio- and Enantioselective Bromoaminocyclization of (E)-Cinnamyl Tosylcarbamates. An Approach to a Class of Synthetically Versatile Functionalized Molecules.

    PubMed

    Pan, Hongjie; Huang, Hu; Liu, Weigang; Tian, Hua; Shi, Yian

    2016-03-01

    A highly regio- and enantioselective bromoaminocyclization of (E)-cinnamyl tosylcarbamates catalyzed by a chiral phosphine oxide-Sc(OTf)3 complex is described. A wide variety of optically active aryl 5-bromo-1,3-oxazinan-2-ones can be obtained with high yield and enantioselectivity.

  20. The rph1 gene is a common contributor to the evolution of phosphine resistance in independent field isolates of Rhyzopertha dominica.

    PubMed

    Mau, Yosep S; Collins, Patrick J; Daglish, Gregory J; Nayak, Manoj K; Pavic, Hervoika; Ebert, Paul R

    2012-01-01

    Phosphine is the only economically viable fumigant for routine control of insect pests of stored food products, but its continued use is now threatened by the world-wide emergence of high-level resistance in key pest species. Phosphine has a unique mode of action relative to well-characterised contact pesticides. Similarly, the selective pressures that lead to resistance against field sprays differ dramatically from those encountered during fumigation. The consequences of these differences have not been investigated adequately. We determine the genetic basis of phosphine resistance in Rhyzopertha dominica strains collected from New South Wales and South Australia and compare this with resistance in a previously characterised strain from Queensland. The resistance levels range from 225 and 100 times the baseline response of a sensitive reference strain. Moreover, molecular and phenotypic data indicate that high-level resistance was derived independently in each of the three widely separated geographical regions. Despite the independent origins, resistance was due to two interacting genes in each instance. Furthermore, complementation analysis reveals that all three strains contain an incompletely recessive resistance allele of the autosomal rph1 resistance gene. This is particularly noteworthy as a resistance allele at rph1 was previously proposed to be a necessary first step in the evolution of high-level resistance. Despite the capacity of phosphine to disrupt a wide range of enzymes and biological processes, it is remarkable that the initial step in the selection of resistance is so similar in isolated outbreaks.

  1. Phosphine Oxide-Sc(OTf)3 Catalyzed Highly Regio- and Enantioselective Bromoaminocyclization of (E)-Cinnamyl Tosylcarbamates. An Approach to a Class of Synthetically Versatile Functionalized Molecules.

    PubMed

    Pan, Hongjie; Huang, Hu; Liu, Weigang; Tian, Hua; Shi, Yian

    2016-03-01

    A highly regio- and enantioselective bromoaminocyclization of (E)-cinnamyl tosylcarbamates catalyzed by a chiral phosphine oxide-Sc(OTf)3 complex is described. A wide variety of optically active aryl 5-bromo-1,3-oxazinan-2-ones can be obtained with high yield and enantioselectivity. PMID:26894481

  2. 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

  3. 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

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

    PubMed

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

    2016-03-18

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

  5. 1,2-Migration of phosphorus-centered anions on ate-type copper carbenoids and its application for the synthesis of new potent phosphine ligands.

    PubMed

    Kondo, Junichi; Someya, Hidenori; Kinoshita, Hidenori; Shinokubo, Hiroshi; Yorimitsu, Hideki; Oshima, Koichiro

    2005-12-01

    [chemical reaction: see text]. Diorganophosphide anions, which usually function as nontransferable ligands on mixed cuprates, undergo smooth 1,2-migration on ate-type copper carbenoids. Phosphinodisilylmethylcoppers prepared by this protocol are converted into the corresponding phosphines, which can be used as bulky, highly basic and air-stable ligands.

  6. Chloridotris(penta­fluoro­benzene­thiol­ato-κS)[tris­(4-fluoro­phen­yl)phosphine-κP]osmium(IV)

    PubMed Central

    Arias, Asdrúbal; Meléndez, Lidia; Bernès, 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 Os—Cl bond length. The phosphine ligand trans to the chloride ligand reveals a short Os—P bond length compared to other chloride–phosphine OsIV complexes (average = 2.40 Å). 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 π–π contacts between inversion-related thiol­ate C6F5 rings, with a centroid–centroid separation of 3.659 (8) Å. PMID:21580558

  7. Dichlorido(η4-cyclo­octa-1,5-diene)bis­(triphenyl­phosphine)osmium(II)

    PubMed Central

    Ye, Chen; Wen, Ting Bin

    2009-01-01

    The OsII atom in the title compound, [OsCl2(C8H12)(C18H15P)2], is located on a crystallographic twofold axis and adopts a distorted octa­hedral coordination geometry. The two triphenyl­phosphine ligands are trans to each other, while the two chlorine ligands are cis-disposed. The coordination is completed by the cyclo­octa­diene (COD) ligand with bonding to the two olefin double bonds. The C=C bond has a length of 1.403 (6) Å, which is significntly longer than a free olefinic double bond (≃1.34 Å). PMID:21577759

  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.

  9. 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.

  10. Regioselectivity of the photochemical addition of phosphine to unsaturated hydrocarbons in the atmospheres of Jupiter and Saturn.

    PubMed

    Guillemin, J C; Le Serre, S; Lassalle, L

    1997-01-01

    Phosphine (PH3) has been observed in the atmospheres of Jupiter and Saturn. We have studied the regioselectivity in the gaseous phase of the photochemical addition of PH3 to propene 1, propadiene 2, propyne 3, 1,3-butadiene 4 and 1,3-butadiyne 5. The photolysis were performed at 185 and 254 nm. The volatile products formed in these reactions were characterized by 1H and 31P NMR. The n-propylphosphine 6 and the isopropylphosphine 7 were the major products observed in the photolysis of PH3 with propene. The allylphosphine 8 was obtained when most of the light was absorbed by propene. This allylphosphine was the main product formed in the photolysis of PH3 in the presence of propadiene; the methylvinylphosphine 10 being not detected in these experiments, the reaction presents a very high regioselectivity. When most of the light was absorbed by propadiene, the propargylphosphine 9 was also observed. The photolysis of PH3 in the presence of propyne led to the E- and Z-1-propenylphosphines 12a,b and small amounts of methylvinylphosphine 10. Even when most of the light was absorbed by propyne, the propargylphosphine 9 was not observed. The Z-1-butene-3-ynylphosphine 13a and a mixture of primary phosphines containing the E-and Z-2-butenylphosphines 14a,b were obtained as major products when 1,3-butadiyne and 1,3-butadiene respectively where photolyzed with PH3. A high regioselectivity was thus observed in the photolysis of PH3 with an alkyne or an allene but alkenes led to mixtures of products.

  11. Steric and Electronic Effects of Bidentate Phosphine Ligands on Ruthenium(II)-Catalyzed Hydrogenation of Carbon Dioxide.

    PubMed

    Zhang, Pan; Ni, Shao-Fei; Dang, Li

    2016-09-20

    The reactivity difference between the hydrogenation of CO2 catalyzed by various ruthenium bidentate phosphine complexes was explored by DFT. In addition to the ligand dmpe (Me2 PCH2 CH2 PMe2 ), which was studied experimentally previously, a more bulky diphosphine ligand, dmpp (Me2 PCH2 CH2 CH2 PMe2 ), together with a more electron-withdrawing diphosphine ligand, PN(Me) P (Me2 PCH2 N(Me) CH2 PMe2 ), have been studied theoretically to analyze the steric and electronic effects on these catalyzed reactions. Results show that all of the most favorable pathways for the hydrogenation of CO2 catalyzed by bidentate phosphine ruthenium dihydride complexes undergo three major steps: cis-trans isomerization of ruthenium dihydride complex, CO2 insertion into the Ru-H bond, and H2 insertion into the ruthenium formate ion. Of these steps, CO2 insertion into the Ru-H bond has the lowest barrier compared with the other two steps in each preferred pathway. For the hydrogenation of CO2 catalyzed by ruthenium complexes of dmpe and dmpp, cis-trans isomerization of ruthenium dihydride complex has a similar barrier to that of H2 insertion into the ruthenium formate ion. However, in the reaction catalyzed by the PN(Me) PRu complex, cis-trans isomerization of the ruthenium dihydride complex has a lower barrier than H2 insertion into the ruthenium formate ion. These results suggest that the steric effect caused by the change of the outer sphere of the diphosphine ligand on the reaction is not clear, although the electronic effect is significant to cis-trans isomerization and H2 insertion. This finding refreshes understanding of the mechanism and provides necessary insights for ligand design in transition-metal-catalyzed CO2 transformation. PMID:27500596

  12. 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; Näther, 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 π-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.

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

    PubMed

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

    2016-03-18

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

  14. 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.

  15. Redox-active phosphines: synthesis and crystal structures of palladium(II) complexes of a metallaphosphine in two different oxidation states.

    PubMed

    Tohmé, Ayham; Labouille, Stéphanie; Roisnel, Thierry; Dorcet, Vincent; Carmichael, Duncan; Paul, Frédéric

    2014-05-21

    The redox-active metallaphosphine [Fe(dppe)(η(5)-C5Me5)(C≡C-PPh2)] reacts with [Pd(1,5-cod)Cl2] to give mono- and bis-phosphine coordinated palladium centres as a function of stoichiometry, and these complexes provide a stable redox-active platform which allows reversible one-electron {Fe(II)→Fe(III)(+)} oxidations within the palladium coordination sphere. PMID:24710466

  16. 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

  17. Intramolecular [4 + 2] cycloadditions of 1,3-enynes or arylalkynes with alkenes with highly reactive cationic phosphine Au(I) complexes.

    PubMed

    Nieto-Oberhuber, Cristina; López, Salomé; Echavarren, Antonio M

    2005-05-01

    New Au(I) complexes with bulky, biphenyl phosphines are the most reactive catalysts for the cyclizations of enynes. 1,6-Enynes with an aryl ring at the alkyne give 2,3,9,9a-tetrahydro-1H-cyclopenta[b]naphthalenes by a 5-exo-dig cyclization followed by a Nazarov-type ring expansion. 1,8-Dien-3-ynes also cyclize by a 5-exo-dig pathway to form hydrindanes. PMID:15853316

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

    NASA Astrophysics Data System (ADS)

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

    1994-01-01

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

  19. Chemical Reaction between Boric Acid and Phosphine Indicates Boric Acid as an Antidote for Aluminium Phosphide Poisoning

    PubMed Central

    Soltani, Motahareh; Shetab-Boushehri, Seyed F.; Shetab-Boushehri, Seyed V.

    2016-01-01

    Objectives: Aluminium phosphide (AlP) is a fumigant pesticide which protects stored grains from insects and rodents. When it comes into contact with moisture, AlP releases phosphine (PH3), a highly toxic gas. No efficient antidote has been found for AlP poisoning so far and most people who are poisoned do not survive. Boric acid is a Lewis acid with an empty p orbital which accepts electrons. This study aimed to investigate the neutralisation of PH3 gas with boric acid. Methods: This study was carried out at the Baharlou Hospital, Tehran University of Medical Sciences, Tehran, Iran, between December 2013 and February 2014. The volume of released gas, rate of gas evolution and changes in pH were measured during reactions of AlP tablets with water, acidified water, saturated boric acid solution, acidified saturated boric acid solution, activated charcoal and acidified activated charcoal. Infrared spectroscopy was used to study the resulting probable adduct between PH3 and boric acid. Results: Activated charcoal significantly reduced the volume of released gas (P <0.01). Although boric acid did not significantly reduce the volume of released gas, it significantly reduced the rate of gas evolution (P <0.01). A gaseous adduct was formed in the reaction between pure AlP and boric acid. Conclusion: These findings indicate that boric acid may be an efficient and non-toxic antidote for PH3 poisoning. PMID:27606109

  20. Insights from selective non-phosphinic inhibitors of MMP-12 tailored to fit with an S1' loop canonical conformation.

    PubMed

    Devel, Laurent; Garcia, Sandra; Czarny, Bertrand; Beau, Fabrice; LaJeunesse, Evelyne; Vera, Laura; Georgiadis, Dimitris; Stura, Enrico; Dive, Vincent

    2010-11-12

    After the disappointment of clinical trials with early broad spectrum synthetic inhibitors of matrix metalloproteinases (MMPs), the field is now resurging with a new focus on the development of selective inhibitors that fully discriminate between different members of the MMP family with several therapeutic applications in perspective. Here, we report a novel class of highly selective MMP-12 inhibitors, without a phosphinic zinc-binding group, designed to plunge deeper into the S(1)' cavity of the enzyme. The best inhibitor from this series, identified through a systematic chemical exploration, displays nanomolar potency toward MMP-12 and selectivity factors that range between 2 and 4 orders of magnitude toward a large set of MMPs. Comparison of the high resolution x-ray structures of MMP-12 in free state or bound to this new MMP-12 selective inhibitor reveals that this compound fits deeply within the S(1)' specificity cavity, maximizing surface/volume ratios, without perturbing the S(1)' loop conformation. This is in contrast with highly selective MMP-13 inhibitors that were shown to select a particular S(1)' loop conformation. The search for such compounds that fit precisely to preponderant S(1)' loop conformation of a particular MMP may prove to be an alternative effective strategy for developing selective inhibitors of MMPs.

  1. Chemical Reaction between Boric Acid and Phosphine Indicates Boric Acid as an Antidote for Aluminium Phosphide Poisoning

    PubMed Central

    Soltani, Motahareh; Shetab-Boushehri, Seyed F.; Shetab-Boushehri, Seyed V.

    2016-01-01

    Objectives: Aluminium phosphide (AlP) is a fumigant pesticide which protects stored grains from insects and rodents. When it comes into contact with moisture, AlP releases phosphine (PH3), a highly toxic gas. No efficient antidote has been found for AlP poisoning so far and most people who are poisoned do not survive. Boric acid is a Lewis acid with an empty p orbital which accepts electrons. This study aimed to investigate the neutralisation of PH3 gas with boric acid. Methods: This study was carried out at the Baharlou Hospital, Tehran University of Medical Sciences, Tehran, Iran, between December 2013 and February 2014. The volume of released gas, rate of gas evolution and changes in pH were measured during reactions of AlP tablets with water, acidified water, saturated boric acid solution, acidified saturated boric acid solution, activated charcoal and acidified activated charcoal. Infrared spectroscopy was used to study the resulting probable adduct between PH3 and boric acid. Results: Activated charcoal significantly reduced the volume of released gas (P <0.01). Although boric acid did not significantly reduce the volume of released gas, it significantly reduced the rate of gas evolution (P <0.01). A gaseous adduct was formed in the reaction between pure AlP and boric acid. Conclusion: These findings indicate that boric acid may be an efficient and non-toxic antidote for PH3 poisoning.

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

    NASA Astrophysics Data System (ADS)

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

    2016-06-01

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

  3. Polymorphism of Phosphine-Protected Gold Nanoclusters: Synthesis and Characterization of a New 22-Gold-Atom Cluster.

    PubMed

    Zhang, Qian-Fan; Williard, Paul G; Wang, Lai-Sheng

    2016-05-01

    A new Au22 nanocluster, protected by bis(2-diphenyl-phosphino)ethyl ether (dppee or C28 H28 OP2 ) ligand, has been synthsized and purified with high yield. Electrospray mass spectrometry shows that the new cluster has a formula of Au22 (dppee)7 , containing 22 gold atoms and seven dppee ligands. The cluster is found to be stable as a solid, but metastable in solution. The new cluster has been characterized by UV-Vis-NIR absorption spectroscopy, collision-induced dissociation, and (31) P-NMR. The properties of the new cluster have been compared with the previous Au22 (dppo)6 nanocluster (dppo = 1,8-bis(diphenyl-phosphino)octane or C32 H36 P2 ), which contains two fused Au11 units. All the experimental data indicate that the new Au22 (dppee)7 cluster is different from the previously known Au22 (dppo)6 cluster and represents a new Au22 core, which contains most likely one Au11 motif with several Au2 (dppee) or Au(dppee) units. The Au22 (dppee)7 cluster provides a new example of the ligand effects on the nuclearity and structural polymorphism of phosphine-protected atom-precise gold nanoclusters.

  4. Ultrafast relaxation dynamics of phosphine-protected, rod-shaped Au20 clusters: interplay between solvation and surface trapping.

    PubMed

    Zhou, Meng; Long, Saran; Wan, Xiankai; Li, Yang; Niu, Yingli; Guo, Qianjin; Wang, Quan-Ming; Xia, Andong

    2014-09-14

    The exact interaction between Au cores and surface ligands remains largely unknown because of the complexity of the structure and chemistry of ligand/Au-core interfaces in ligand-protected Au nanoclusters (AuNCs), which are commonly found in many organic-inorganic complexes. Here, femtosecond transient absorption measurement of the excited-state dynamics of a newly synthesized phosphine-protected cluster [Au20(PPhpy2)10Cl4]Cl2 (1) is reported. Intramolecular charge transfer (ICT) from the Au core to the peripheral ligands was identified. Furthermore, we found that solvation strongly affected ICT at ligand/Au-core interfaces while by choosing several typical alcoholic solvents with different intrinsic solvation times, we successfully observed that excited-state relaxation dynamics together with displacive excited coherent oscillation of Au20 clusters were significantly modulated through the competition between solvation and surface trapping. The results provide a fundamental understanding of the structure-property relationships of the solvation-dependent core-shell interaction of AuNCs for the potential applications in catalysis, sensing and nanoelectronics.

  5. Dissociation and reduction of covalent β-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 β-lactoglobulin (β-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 β-LG reacted with 4MBQ when present in equimolar ratio at 20°C (pH 8.0) to yield the protein-phenol adduct (β-LG-Q). Following treatment with sulfite, DTT, or TCEP, 75, 68, or 36%, respectively, of the formed β-LG-Q adduct dissociated. Different reaction mechanisms were proposed for the reduction of β-LG and β-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

  6. Imino-phosphine palladium(II) and platinum(II) complexes: synthesis, molecular structures and evaluation as antitumor agents.

    PubMed

    Motswainyana, William M; Onani, Martin O; Madiehe, Abram M; Saibu, Morounke; Thovhogi, Ntevheleni; Lalancette, Roger A

    2013-12-01

    The imino-phosphine ligands L1 and L2 were prepared via condensation reaction of 2-(diphenylphosphino)benzaldehyde with substituted anilines and obtained in very good yields. An equimolar reaction of L1 and L2 with either PdCl2(cod) or PtCl2(cod) gave new palladium(II) and platinum(II) complexes 1-4. The compounds were characterized by elemental analysis, IR, (1)H and (31)P NMR spectroscopy. The molecular structures of 2, 3 and 4 were confirmed by X-ray crystallography. All the three molecular structures crystallized in monoclinic C2/c space system. The coordination geometry around the palladium and platinum atoms in respective structures exhibited distorted square planar geometry at the metal centers. The complexes were evaluated in vitro for their cytotoxic activity against human breast (MCF-7) and human colon (HT-29) cancer cells, and they exhibited growth inhibitory activities and selectivity that were superior to the standard compound cisplatin.

  7. 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 5°C and 20°C. All of the developmental stages showed greater susceptibility to PH3 at 20°C than at 5°C, 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

  8. 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

  9. A balanced procedure for the treatment of cluster-ligand interactions on gold phosphine systems in catalysis.

    PubMed

    Mollenhauer, Doreen; Gaston, Nicola

    2014-05-15

    Ligand-protected metal clusters are difficult to describe within density functional theory due to the need to treat the electronic structure of the cluster, possible charge transfer between the ligands and the cluster, and weak ligand-ligand interactions in a balanced manner. We demonstrate the use of an appropriate, stepwise benchmarking process that accounts for the nonadditivity of these different contributions to stability and catalytic activity. We consider both open- and closed-shell clusters, differently charged systems, and ligands of increasing complexity for gold phosphine systems. The use of a dispersion correction to density functional calculations was found to be crucial for both structure optimization and the calculation of binding energies. We find that PBE-D3 performs well with a variation in energetics of 0.7-10.9 kcal/mol, PBE0-D3 better with 0.0-3.3 kcal/mol, and B2PLYP-D3 the best with 0.2-2.4 kcal/mol, when compared to the best available benchmark [CCSD(T) or SCS-MP2]. Our systematic procedure clarifies that these functionals all give accurate results for certain cases, but for the total performance over a range of interactions, they perform in accordance with Jacob's ladder. PMID:24648301

  10. Phosphine oxide derivatives as hosts for blue phosphors: A joint theoretical and experimental study of their electronic structure

    SciTech Connect

    Kim, Dongwook; Salman, Seyhan; Coropceanu, Veaceslav; Salomon, Eric; Padmaperuma, Asanga B.; Sapochak, Linda S.; Kahn, Antoine; Bredas, Jean-Luc

    2010-01-12

    We report on a joint theoretical and experimental investigation of the electronic structure of a series of bis(diphenylphosphine oxide) derivatives containing a central aromatic core with high triplet energy. Such molecules can serve as host material in the emissive layer of blue electro-phosphorescent organic devices. The aromatic cores considered in the theoretical study consist of biphenyl, fluorene, dibenzofuran, dibenzothiophene, dibenzothiophenesulfone or carbazole, linked to the two phosphoryl groups in either para or meta positions. With respect to the isolated core molecules, it is found that addition of the diphenylphosphine oxide moieties has hardly any impact on the core geometry and only slightly reduces the energy of the lowest triplet state (by at most ~0.2 eV). However, the diphenylphosphine oxide functionalities significantly impact the ionization potential and electron affinity values, in a way that is different for para and meta substitutions. Excellent comparison is obtained between the experimental UPS and IPES spectra of the para biphenyl and meta dibenzothiophene and dibenzothiophenesulfone compounds and the simulated spectra. In general, the phosphine oxide derivatives present triplet energies that are calculated to be at least 0.2 eV higher than those of currently widely used blue phosphorescent emitters.

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

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

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

  12. Bioavailability and bioconcentration potential of perfluoroalkyl-phosphinic and -phosphonic acids in zebrafish (Danio rerio): Comparison to perfluorocarboxylates and perfluorosulfonates.

    PubMed

    Chen, Fangfang; Gong, Zhiyuan; Kelly, Barry C

    2016-10-15

    Currently, information regarding bioavailability and bioconcentration potential of perfluoroalkyl phosphinic acids (PFPiAs) in aquatic organisms does not exist. The main objective of the present study was to assess uptake and elimination kinetics of PFPiAs in zebrafish (Danio rerio) following aqueous exposure. The results showed that PFPiA exposure can result in very high steady-state bioconentration factors (BCFss), compared to perfluorocarboxylates and perfluorosulfonates.C6/C10 PFPiA exhibited the highest BCFss, ranging between 10(7) and 10(10), orders of magnitude higher than those for long-chain perfluorocarboxylates. Strong positive relationships were observed between BCFss versus the membrane-water distribution coefficient (Dmw) and the protein-water partition coefficient (Kpw) of the studied perfluoroalkyl substances. However, BCFss exhibited a substantial drop for the very hydrophobic PFPiAs (C8/C10 and C6/C12 PFPiAs). The reduced BCFss of these long-chain PFPiAs (perfluoroalkyl chain length=18; Dmw=10(9)) is likely the result of reduced bioavailability due to interaction with solute molecules/organic matter present in the water phase and/or reduced gill membrane permeability. While PFPiAs can be metabolized to perfluoroalkyl phosphonic acids, the metabolic transformation rate seems insufficient to counteract the high degree of uptake across gill membranes. These findings help to better understand exposure pathways and bioaccumulation behavior of these important perfluorinated acids in aquatic systems. PMID:27285794

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

    PubMed

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

    1999-08-23

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

  14. 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.

  15. PCN pincer palladium(II) complex catalyzed enantioselective hydrophosphination of enones: synthesis of pyridine-functionalized chiral phosphine oxides as NC(sp(3))O pincer preligands.

    PubMed

    Hao, Xin-Qi; Huang, Juan-Juan; Wang, Tao; Lv, Jing; Gong, Jun-Fang; Song, Mao-Ping

    2014-10-17

    A series of chiral PCN pincer Pd(II) complexes VI-XIII with aryl-based aminophosphine-imidazoline or phosphinite-imidazoline ligands were synthesized and characterized. They were examined as enantioselective catalysts for the hydrophosphination of enones. Among them, complex IX, which features a Ph2PO donor as well as an imidazoline donor with (4S)-phenyl and N-Tol-p groups, was found to be the optimal catalyst. Thus, in the presence of 2-5 mol % of complex IX a wide variety of enones reacted smoothly with diarylphosphines to give the corresponding chiral phosphine derivatives in high yields with enantioselectivities of up to 98% ee. In particular, heteroaryl species such as 2-thienyl-, 2-furyl-, and 2-pyridinyl-containing enones that have a strong coordination ability to the Pd center were also appropriate substrates for the current catalytic system. For example, hydrophosphination of 2-alkenoylpyridines with diphenylphosphine followed by oxidation with H2O2 afforded the corresponding pyridine-functionalized chiral phosphine oxides in good yields with good to excellent enantioselectivities (10 examples, up to 95% ee). Furthermore, it had been demonstrated that the obtained pyridine-containing phosphine oxide acted as a tridentate ligand in the reaction with PdCl2 to form an intriguing NCsp(3)O pincer Pd(II) complex via Csp(3)-H bond activation, which to our knowledge is the first example of a chiral DCsp(3)D' Pd pincer (D ≠ D'; D and D' denote donor atoms such as P, N, etc.).

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

    PubMed

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

    2011-12-01

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

  17. 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.

  18. Arsenic speciation in environmental waters by a new specific phosphine modified polymer microsphere preconcentration and HPLC-ICP-MS determination.

    PubMed

    Jia, Xiaoyu; Gong, Dirong; Wang, Jiani; Huang, Fuyi; Duan, Taicheng; Zhang, Xian

    2016-11-01

    A new specific phosphine modified polymer microsphere (PPMs) was designed and used as the core adsorbent to comprehensively enrich both inorganic and organic arsenic species in environmental waters by on line solid-phase extraction (SPE). Avoiding any redox reagent, all the four arsenic species have been quantitatively retained on the home made mini-column with large number of positively charged adsorption groups, and then eluted rapidly (within seconds) with a mixed solution of ammonium nitrate and ammonium dihydrogen phosphate. The trace separation and determination of As(III), DMA, MMA and As(V) species have been simultaneously achieved by high performance liquid chromatography hyphenated to inductively coupled plasma spectrometry (HPLC-ICP-MS) technique. This work has developed a versatile tri-n-butylphosphine functionalized polymer microsphere for an efficient and reliable on-line of simultaneous preconcentration and detection of inorganic and organic arsenic speciation. Under the optimized experimental conditions, the enrichment factors obtained for As(III) and DMA with 25mL sample solution were 28, while for MMA and As(V) reached 30. The low detection limits of 1.2ngL(-1), 0.96ngL(-1), 0.82ngL(-1) and 0.91ngL(-1), with the relative standard deviations (RSDs) of 3.9%, 5.6%, 3.2% and 4.5% were obtained for As(III), DMA, MMA and As(V), respectively. The developed method was validated by analyzing Certified Reference Materials GSBZ 07-3171-2014, promising for routine monitoring of arsenic species in lake water, river water and seawater samples. PMID:27591635

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

    PubMed

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

    2011-08-15

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

  20. 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

  1. Electrophysiological and molecular mechanisms of protection by iron sucrose against phosphine-induced cardiotoxicity: a time course study.

    PubMed

    Solgi, Reza; Baghaei, Amir; Golaghaei, Ali; Hasani, Shokoufeh; Baeeri, Maryam; Navaei, Mona; Ostad, Seyyed Nasser; Hosseini, Rohollah; Abdollahi, Mohammad

    2015-01-01

    The present study was designed for determining the exact mechanism of cytotoxic action of aluminum phosphide (AlP) in the presence of iron sucrose as the proposed antidote. Rats received AlP (12 mg/kg) and iron sucrose (5-30 mg/kg) in various sets and were connected to cardiovascular monitoring device. After identification of optimum doses of AlP and iron sucrose, rats taken in 18 groups received AlP (6 mg/kg) and iron sucrose (10 mg/kg), treated at six different time points, and then their hearts were surgically removed and used for evaluating a series of mitochondrial parameters, including cell lipid peroxidation, antioxidant power, mitochondrial complex activity, ADP/ATP ratio and process of apoptosis. ECG changes of AlP poisoning, including QRS, QT, P-R, ST, BP and HR were ameliorated by iron sucrose (10 mg/kg) treatment. AlP initiated its toxicity in the heart mitochondria through reducing mitochondrial complexes (II, IV and V), which was followed by increasing lipid peroxidation and the ADP/ATP ratio and declining mitochondrial membrane integrity that ultimately resulted in cell death. AlP in acute exposure (6 mg/kg) resulted in an increase in hydroxyl radicals and lipid peroxidation in a time-dependent fashion, suggesting an interaction of delivering electrons of phosphine with mitochondrial respiratory chain and oxidative stress. Iron sucrose, as an electron receiver, can compete with mitochondrial respiratory chain complexes and divert electrons to another pathway. The present findings supported the idea that iron sucrose could normalize the activity of mitochondrial electron transfer chain and cellular ATP level as vital factors for cell escaping from AlP poisoning. PMID:25906050

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

    SciTech Connect

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

    2009-12-10

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

  3. 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)

  4. Tris(hydroxymethyl)phosphine, P(CH2OH)3 - A convenient and effective new reagent for the fixation of protein samples for SEM imaging.

    PubMed

    Wyllie, Megan J; Turner, Helen; Henderson, William

    2016-10-01

    Tris(hydroxymethyl)phosphine [P(CH2OH)3, THP] is demonstrated to be an alternative fixative to glutaraldehyde for preparation of proteinaceous specimens for SEM analysis. THP is easily prepared from commercially-available [P(CH2OH)4]Cl, and unlike many other alkylphosphines, is reasonably air-stable [>7days at pH 7-8]. Experiments carried out with chicken breast muscle, cross-sectioned perpendicular to the muscle fibres and imaged using SEM, indicate that THP effectively fixes the muscle structure with minimal discolouration of the sample.

  5. Catalytic Enantioselective Carbon-Oxygen Bond Formation: Phosphine-Catalyzed Synthesis of Benzylic Ethers via the Oxidation of Benzylic C-H Bonds.

    PubMed

    Ziegler, Daniel T; Fu, Gregory C

    2016-09-21

    Benzylic alcohols and ethers are common subunits in bioactive molecules, as well as useful intermediates in organic chemistry. In this Communication, we describe a new approach to the enantioselective synthesis of benzylic ethers through the chiral phosphine-catalyzed coupling of two readily available partners, γ-aryl-substituted alkynoates and alcohols, under mild conditions. In this process, the alkynoate partner undergoes an internal redox reaction. Specifically, the benzylic position is oxidized with good enantioselectivity, and the alkyne is reduced to the alkene. PMID:27618638

  6. Effect of exposure period on degree of dominance of phosphine resistance in adults of Rhyzopertha dominica (Coleoptera: Bostrychidae) and Sitophilus oryzae (Coleoptera: Curculionidae).

    PubMed

    Daglish, Gregory J

    2004-08-01

    Degree of dominance of phosphine resistance was investigated in adults of Rhyzopertha dominica F and Sitophilus oryzae L. Efficacy of the grain fumigant phosphine depends on both concentration and exposure period, which raises the possibility that dominance levels vary with exposure period. New and published data were used to test this possibility in adults of R dominica and S oryzae fumigated for periods of up to 144 h. The concentrations required for control of homozygous resistant and susceptible strains and their F1 hybrids decreased with increasing exposure period. For both species the response lines for the homozygous resistant and susceptible strains and their F1 hybrids were parallel. Therefore, neither dominance level nor resistance factor was affected by exposure period. Resistance was incompletely recessive and the level of dominance, calculated at 50% mortality level, was -0.59 for R dominica and -0.65 for S oryzae. The resistant R dominica strain was 30.9 times more resistant than the susceptible strain, compared with 8.9 times for the resistant S oryzae strain. The results suggest that developing discriminating doses for detecting heterozygote adults of either species will be difficult.

  7. Structure-guided, single-point modifications in the phosphinic dipeptide structure yield highly potent and selective inhibitors of neutral aminopeptidases.

    PubMed

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

    2014-10-01

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

  8. Determination of polyfluoroalkyl phosphoric acid diesters, perfluoroalkyl phosphonic acids, perfluoroalkyl phosphinic acids, perfluoroalkyl carboxylic acids, and perfluoroalkane sulfonic acids in lake trout from the Great Lakes region.

    PubMed

    Guo, Rui; Reiner, Eric J; Bhavsar, Satyendra P; Helm, Paul A; Mabury, Scott A; Braekevelt, Eric; Tittlemier, Sheryl A

    2012-11-01

    A comprehensive method to extract perfluoroalkyl carboxylic acids, perfluoroalkane sulfonic acids, perfluoroalkyl phosphonic acids, perfluoroalkyl phosphinic acids, and polyfluoroalkyl phosphoric acid diesters simultaneously from fish samples has been developed. The recoveries of target compounds ranged from 78 % to 121 %. The new method was used to analyze lake trout (Salvelinus namaycush) from the Great Lakes region. The results showed that the total perfluoroalkane sulfonate concentrations ranged from 0.1 to 145 ng/g (wet weight) with perfluorooctane sulfonate (PFOS) as the dominant contaminant. Concentrations in fish between lakes were in the order of Lakes Ontario ≈ Erie > Huron > Superior ≈ Nipigon. The total perfluoroalkyl carboxylic acid concentrations ranged from 0.2 to 18.2 ng/g wet weight. The aggregate mean perfluorooctanoic acid (PFOA) concentration in fish across all lakes was 0.045 ± 0.023 ng/g. Mean concentrations of PFOA were not significantly different (p > 0.1) among the five lakes. Perfluoroalkyl phosphinic acids were detected in lake trout from Lake Ontario, Lake Erie, and Lake Huron with concentration ranging from non-detect (ND) to 0.032 ng/g. Polyfluoroalkyl phosphoric acid diesters were detected only in lake trout from Lake Huron, at levels similar to perfluorooctanoic acid.

  9. The Role of Tris(2-carboxyethyl)phosphine Reducing Agent in the Controlled Formation of α,ω-Alkanedithiols Monolayers on Au(111) with Monocoordinated and Bicoordinated Configurations.

    PubMed

    Euti, Esteban M; Vélez-Romero, Patricio; Leiva, Ezequiel P M; Macagno, Vicente A; Paredes-Olivera, Patricia A; Patrito, E Martín; Cometto, Fernando P

    2016-09-20

    The addition of the reducing agent tris(2-carboxyethyl) phosphine (TCEP) during the formation of α,ω-alkanedithiols monolayers on Au(111) using the immersion method produces the assembly of monolayers with bicoordinated molecules (both S-terminal groups bound to the surface) that have a reductive desorption potential that is more positive than for monolayers with monocoordinated molecules in a standing up configuration. We show that the use of TCEP either during formation of the monolayer or as a post treatment procedure allows the controlled formation of monolayers with bicoordinated or monocoordinated configurations. Density functional theory (DFT) calculations were performed to elucidate the role of TCEP in the formation of the bicoordinated configuration. We investigated the TCEP-dithiol interaction in ethanol solvent as well as the coadsorption of trimethylphosphine with 1,2-ethanedithiol on Au(111). The Brønsted base character of the phosphine facilitates the H exchange from the -SH groups of the dithiol to the phosphorus atom of TCEP with very low activation energy barriers, thus allowing the thiolate groups to bind to the Au(111) surface, thus yielding the bicoordinated configuration. Dithiol lifting mechanisms such as H exchange between S atoms and the formation of intra/inter layer disulfide bonds have much higher energy barriers. PMID:27579725

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

    SciTech Connect

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

    2014-10-09

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

  11. 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

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

    PubMed

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

    2010-01-01

    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

  13. Molecular assembly of an achiral phosphine and a chiral primary amine: a highly efficient supramolecular catalyst for the enantioselective Michael reaction of aldehydes with maleimides.

    PubMed

    Yang, Wei; Jiang, Ke-Zhi; Lu, Xing; Yang, Hua-Meng; Li, Li; Lu, Yixin; Xu, Li-Wen

    2013-06-01

    A combined catalyst system of a cinchonidine-derived primary amine and triphenylphosphine (CD-NH2 /PPh3 ) exhibited high catalytic performance in the Michael reaction of aldehydes with maleimides, thereby affording the corresponding functionalized aldehydes in excellent yields (up to 99 %) and enantioselectivities (>99 % ee). More interestingly, the significance of the phosphine in enhancing the enantioselectivities in the chiral-primary-amine-catalyzed Michael reaction was revealed. Furthermore, we explored the origin of the reaction mechanism in the Michael addition promoted by the dual organocatalytic system. On the basis of experimental results and spectroscopic analysis, such as UV/Vis, fluorescence emission (FL), NMR, and circular dichroism (CD) spectroscopy, as well as ESI-MS, we found that the molecular assembly of phosphine and primary amine played a crucial role in this enantioselective reaction, in which a possible supramolecular complex was formed as an effective chiral catalyst through noncovalent molecular interactions of a cinchona alkaloid-derived primary amine with triphenylphosphine.

  14. Metabolism of aspirin and procaine in mice pretreated with O-4-nitrophenyl methyl(phenyl)phosphinate or O-4-nitrophenyl diphenylphosphinate

    SciTech Connect

    Joly, J.M.; Brown, T.M.

    1986-07-01

    Concentrations of (carboxyl-/sup 14/C)procaine in blood of mice were increased threefold for 27 min by exposure to O-4-nitrophenyl diphenylphosphinate 2 hr prior to (carboxyl-/sup 14/C)procaine injection ip, while there was no effect of O-4-nitrophenyl methyl(phenyl)phosphinate pretreatment. There was no effect of either organophosphinate on the primary hydrolysis of (acetyl-l-/sup 14/C)aspirin when assessed by the expiration of (/sup 14/C)carbon dioxide; however, O-4-nitrophenyl diphenylphosphinate pretreatment produced transient increases in blood concentrations of both (carboxyl-/sup 14/C)aspirin and (carboxyl-/sup 14/C)salicylic acid following administration of (carboxyl-/sup 14/C)aspirin. Liver carboxylesterase activity in O-4-nitrophenyl diphenylphosphinate pretreated mice was 11% of control activity. These results indicate the potential for drug interaction with O-4-nitrophenyl diphenylphosphinate but not with O-4-nitrophenyl methyl(phenyl)phosphinate. It appears that liver carboxylesterase activity has a minor role in hydrolysis of aspirin in vivo, but may be more important in procaine metabolism.

  15. 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

  16. Two Triazole-Based Phosphine Ligands Prepared via Temperature-Mediated Li/H Exchange: Cu(I) and Au(I) Complexes and Structural Studies.

    PubMed

    Choubey, Bimba; Radhakrishna, Latchupatula; Mague, Joel T; Balakrishna, Maravanji S

    2016-09-01

    The kinetically favored triazole-based phosphine 1-(2-(diphenylphosphino)phenyl)-4-phenyl-1H-1,2,3-triazole (2, L1) and its thermodynamically preferred isomer, 5-(diphenylphosphino)-1,4-diphenyl-1H-1,2,3-triazole (3, L2), were obtained by the temperature-controlled lithiation of 2-bromotriazole followed by the reaction with chlorodiphenylphosphine. The structures of phosphines 2 and 3 were determined by X-ray diffraction. Upon reaction with late transition-metal derivatives (Cu(I), Ag(I), and Au(I)), phosphines 2 and 3 form complexes with monodentate (Cu(I), Ag(I), and Au(I); κ(1)-P), chelate (Cu(I); κ(2)-P,N), bridged bidentate (Cu(I); μ(2)-P,N), and tridentate (Cu(I); μ(2),κ(2)-P,N,N) modes of coordination. Reactions with copper(I) halides produced mono-, di-, and tetranuclear complexes, whereas the reaction of 2 with [Cu(NCCH3)4]BF4 yielded the binuclear complex [Cu2(CH3CN)2{o-Ph2P(C6H4){1,2,3-N3C(Ph)C(H)}-μ-(κ-P,κ-N),κ-N}2](BF4)2 (10) with the ligand acting as a six-electron donor involving phosphorus and two triazole nitrogen atoms. The copper complexes of 2 and 3 containing rhomboid Cu2X2 units, [(Cu)2(μ-X)2{o-Ph2P(C6H4){1,2,3-N3C(Ph)C(H)}-κ-P}2] (4, X = Cl; 5, X = Br), on treatment with 1,10-phenanthroline and 2,2'-bipyridine gave mixed-ligand complexes of the type [(CuX)(N∩N-κ(2)-N,N){o-Ph2P(C6H4){1,2,3-N3C(Ph)C(H)}-κ-P}] (N∩N = 1,10-phen and 2,2'-bipy; X = Cl, Br, and I). PMID:27517883

  17. 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

    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

  18. Iron-Catalyzed Ortho C-H Methylation of Aromatics Bearing a Simple Carbonyl Group with Methylaluminum and Tridentate Phosphine Ligand.

    PubMed

    Shang, Rui; Ilies, Laurean; Nakamura, Eiichi

    2016-08-17

    Iron-catalyzed C-H functionalization of aromatics has attracted widespread attention from chemists in recent years, while the requirement of an elaborate directing group on the substrate has so far hampered the use of simple aromatic carbonyl compounds such as benzoic acid and ketones, much reducing its synthetic utility. We describe here a combination of a mildly reactive methylaluminum reagent and a new tridentate phosphine ligand for metal catalysis, 4-(bis(2-(diphenylphosphanyl)phenyl)phosphanyl)-N,N-dimethylaniline (Me2N-TP), that allows us to convert an ortho C-H bond to a C-CH3 bond in aromatics and heteroaromatics bearing simple carbonyl groups under mild oxidative conditions. The reaction is powerful enough to methylate all four ortho C-H bonds in benzophenone. The reaction tolerates a variety of functional groups, such as boronic ester, halide, sulfide, heterocycles, and enolizable ketones.

  19. Iron-Catalyzed Ortho C-H Methylation of Aromatics Bearing a Simple Carbonyl Group with Methylaluminum and Tridentate Phosphine Ligand.

    PubMed

    Shang, Rui; Ilies, Laurean; Nakamura, Eiichi

    2016-08-17

    Iron-catalyzed C-H functionalization of aromatics has attracted widespread attention from chemists in recent years, while the requirement of an elaborate directing group on the substrate has so far hampered the use of simple aromatic carbonyl compounds such as benzoic acid and ketones, much reducing its synthetic utility. We describe here a combination of a mildly reactive methylaluminum reagent and a new tridentate phosphine ligand for metal catalysis, 4-(bis(2-(diphenylphosphanyl)phenyl)phosphanyl)-N,N-dimethylaniline (Me2N-TP), that allows us to convert an ortho C-H bond to a C-CH3 bond in aromatics and heteroaromatics bearing simple carbonyl groups under mild oxidative conditions. The reaction is powerful enough to methylate all four ortho C-H bonds in benzophenone. The reaction tolerates a variety of functional groups, such as boronic ester, halide, sulfide, heterocycles, and enolizable ketones. PMID:27487172

  20. Partitioning of actinides from high level waste of PUREX origin using octylphenyl-N,N{prime}-diisobutylcarbamoylmethyl phosphine oxide (CMPO)-based supported liquid membrane

    SciTech Connect

    Ramanujam, A.; Dhami, P.S.; Gopalakrishnan, V.; Dudwadkar, N.L.; Chitnis, R.R.; Mathur, J.N.

    1999-06-01

    The present studies deal with the application of the supported liquid membrane (SLM) technique for partitioning of actinides from high level waste of PUREX origin. The process uses a solution of octylphenyl-N,N{prime}-diisobutylcarbamoylmethyl phosphine oxide (CMPO) in n-dodecane as a carrier with a polytetrafluoroethylene support and a mixture of citric acid, formic acid, and hydrazine hydrate as the receiving phase. The studies involve the investigation of such parameters as carrier concentration in SLM, acidity of the feed, and the feed composition. The studies indicated good transport of actinides like neptunium, americium, and plutonium across the membrane from nitric acid medium. A high concentration of uranium in the feed retards the transport of americium, suggesting the need for prior removal of uranium from the waste. The separation of actinides from uranium-lean simulated samples as well as actual high level waste has been found to be feasible using the above technique.

  1. Cyclometalated iridium complexes of bis(aryl) phosphine ligands: catalytic C-H/C-D exchanges and C-C coupling reactions.

    PubMed

    Campos, Jesús; Espada, María F; López-Serrano, Joaquín; Carmona, Ernesto

    2013-06-01

    This work details the synthesis and structural identification of a series of complexes of the (η(5)-C5Me5)Ir(III) unit coordinated to cyclometalated bis(aryl)phosphine ligands, PR'(Ar)2, for R' = Me and Ar = 2,4,6-Me3C6H2, 1b; 2,6-Me2-4-OMe-C6H2, 1c; 2,6-Me2-4-F-C6H2, 1d; R' = Et, Ar = 2,6-Me2C6H3, 1e. Both chloride- and hydride-containing compounds, 2b-2e and 3b-3e, respectively, are described. Reactions of chlorides 2 with NaBArF (BArF = B(3,5-C6H3(CF3)2)4) in the presence of CO form cationic carbonyl complexes, 4(+), with ν(CO) values in the narrow interval 2030-2040 cm(-1), indicating similar π-basicity of the Ir(III) center of these complexes. In the absence of CO, NaBArF forces κ(4)-P,C,C',C″ coordination of the metalated arm (studied for the selected complexes 5b, 5d, and 5e), a binding mode so far encountered only when the phosphine contains two benzylic groups. A base-catalyzed intramolecular, dehydrogenative, C-C coupling reaction converts the κ(4) species 5d and 5e into the corresponding hydrido phosphepine complexes 6d and 6e. Using CD3OD as the source of deuterium, the chlorides 2 undergo deuteration of their 11 benzylic positions whereas hydrides 3 experience only D incorporation into the Ir-H and Ir-CH2 sites. Mechanistic schemes that explain this diversity have come to light thanks to experimental and theoretical DFT studies that are also reported. PMID:23675910

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

    DOE PAGES

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

    2014-10-09

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

  3. Palladium-phosphinous acid complexes catalyzed Suzuki cross-coupling reaction of heteroaryl bromides with phenylboronic acid in water/alcoholic solvents.

    PubMed

    Li, Ben; Wang, Cuiping; Chen, Guang; Zhang, Zhiqiang

    2013-06-01

    Highly active, air-stable and water-soluble palladium-phosphinous acid complexes have been applied to Suzuki cross-coupling reaction of heteroaryl bromides under mild conditions in water/alcoholic solvents. Suzuki cross-coupling reaction of heteroaryl bromides with phenylboronic acid occurred efficiently using palladium phosphinous acid complexes (POPd) and phase transfer catalyst (tetrabutylammonium bromide and polyethylene glycol) in water/ethanol mixture, water/propanol mixture and neat water respectively, the corresponding yields of cross-coupling heteroaryl-aryls were satisfied. The tert-butyl substituted ligand di-tert-butylphosphino in combination with POPd was found to be more active than the same family derived catalysts dipalladium complexes POPd1 and POPd2, and other two kinds of Pd-catalysts Pd(PPh3)4 and Pd2(dba)3. The mechanism of Suzuki cross-coupling reaction between heteroaryl bromides and phenylboronic acid in water was proposed with respect to the key role of phase transfer catalyst on the transmetallation step. Compared with other solid phase transfer catalysts, TBAB was tested as the ideal one. The alkalinity of base and the molar proportion between POPd and TBAB were investigated in water and alcoholic solvents. Notably, in the presence of TBAB adding alcoholic solvents into water enhanced the yields of target products. However in terms of the liquid phase transfer catalyst of PEGs, mixing water into PEGs could slightly decrease the yields with respect to the water free PEGs bulk phase, which was probably due to the homogenous liquid conditions in pure PEGs and weak interactions between PEGs and heteroaryl bromide molecules in water depending on their molecular chain lengths.

  4. Phenylcarbazole and phosphine oxide/sulfide hybrids as host materials for blue phosphors: effectively tuning the charge injection property without influencing the triplet energy.

    PubMed

    Wu, Jie; Liao, Yi; Wu, Shui-Xing; Li, Hai-Bin; Su, Zhong-Min

    2012-02-01

    Compared with red and green phosphorescent organic light-emitting diodes (PHOLEDs), efficient blue PHOLEDs are still scarce, because it is difficult for the host materials for blue phosphors to achieve a trade-off between a wide triplet energy and good charge injection properties. We theoretically studied a series of hybrid phosphine oxide/sulfide-phenylcarbazole host molecules (PO(S)PhCBZs) for blue phosphors through different linkage modes between phenylcarbazole (PhCBZ) and phosphine oxide/sulfide (PO/PS) moieties. The results indicate that the singlet excitons of all PO(S)-PhCBZs are delocalized over the entire molecule with intramolecular charge transfer (ICT) character and different linkage modes cause various degrees of ICT, which determines the injection abilities of carriers from neighboring layers following the order: PO-Phs (PO linked to the phenyl of PhCBZ) > para-POs (PO linked to the para-positions of PhCBZ) > meta-POs (PO linked to the meta-positions of PhCBZ). By contrast, the triplet excitons are confined to the carbazole unit for all PO(S)-PhCBZs. High triplet energies (E(T)) are therefore kept up for all systems, except for para-POs showing a slight drop in E(T) due to the delocalization of their triplet excitons to the phenyl moiety of PhCBZ. All hybrid PO(S)-PhCBZs, especially PO(s)-Phs, exhibit an enhancement in electron injection and triplet energy compared with the most widely used host material (N,N-dicarbazolyl-3,5-benzene) for blue PHOLEDs, and thereby have great potential for application in highly efficient light emitting diodes. PMID:22193557

  5. 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) Å. 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.

  6. Insertion of phosphinidene complexes into the P-H bond of secondary phosphine oxides: a new version of the phospha-Wittig synthesis of P=C double bonds.

    PubMed

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

    2016-01-21

    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

  7. Synthesis, crystal structures and magnetic behaviour of four coordination compounds constructed with a phosphinic amide-TEMPO radical and [M(hfac)2] (M = Cu(II), Co(II) and Mn(II)).

    PubMed

    Reis, Samira G; Del Águila-Sánchez, Miguel A; Guedes, Guilherme P; Ferreira, Glaucio B; Novak, Miguel A; Speziali, Nivaldo L; López-Ortiz, Fernando; Vaz, Maria G F

    2014-10-21

    In the present work we describe the synthesis, crystal structures and magnetic properties of four coordination compounds obtained by assembling a new phosphinic amide containing the TEMPO moiety, 1-piperidinyloxy-4-[(diphenylphosphinyl)amino]-2,2,6,6-tetramethyl radical (dppnTEMPO), with [M(hfac)2] building blocks (M = Cu(II), Co(II), Mn(II)). The crystal structures of the coordination compounds revealed the usefulness of the functionalized radical to provide discrete or extended architectures. In the copper compound () the ligand is coordinated through the oxygen atom of the NP[double bond, length as m-dash]O linkage to the metal, which exists in a square pyramidal or octahedral geometry. For the cobalt and manganese complexes (), both the phosphinic amide and the nitroxide oxygen atoms are involved in the coordination to the metal leading to one dimensional systems. In the cobalt complex () an interesting spin topology in the zig-zag chain was obtained due to the oxygen atom of the phosphinic amide group being μ2 coordinated to two cobalt(ii) ions. The magnetic behaviour of the coordination compounds shows overall antiferromagnetic interactions involving the metal ion and the organic radical. DFT calculations were performed in order to assign the main path for the magnetic interactions. PMID:25177845

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

    2015-12-21

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

  9. 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.

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

    PubMed

    Chen, Su-Ching; Duan, Kow-Jen

    2015-01-01

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

  11. In vitro and in vivo anticancer activity of copper(I) complexes with homoscorpionate tridentate tris(pyrazolyl)borate and auxiliary monodentate phosphine ligands.

    PubMed

    Gandin, Valentina; Tisato, Francesco; Dolmella, Alessandro; Pellei, Maura; Santini, Carlo; Giorgetti, Marco; Marzano, Cristina; Porchia, Marina

    2014-06-12

    Tetrahedral copper(I) TpCuP complexes 1-15, where Tp is a N,N,N-tris(azolyl)borate and P is a tertiary phosphine, have been synthesized and characterized by means of NMR, ESI-MS, and XAS-EXAFS, and X-ray diffraction analyses on the representative complexes 1 and 10, respectively. All copper(I) complexes were evaluated for their antiproliferative activity against a panel of human cancer cell lines (including cisplatin and multidrug-resistant sublines). The two most effective complexes [HB(pz)3]Cu(PCN), 1, and [HB(pz)3]Cu(PTA), 2, showed selectivity toward tumor vs normal cells, inhibition of 26S proteasome activity associated with endoplasmic reticulum (ER) stress, and unfolded protein response (UPR) activation. No biochemical hallmarks of apoptosis were detected, and morphology studies revealed an extensive cytoplasmic vacuolization coherently with a paraptosis-like cell death mechanism. Finally, the antitumor efficacy of complex 1 was validated in the murine Lewis Lung Carcinoma (LLC) model. PMID:24793739

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

    PubMed Central

    Chen, Su-Ching; Duan, Kow-Jen

    2015-01-01

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

  13. Degradation, cleanup, and reusability of octylphenyl-N,N{prime}-diisobutylcarbamoylmethyl phosphine oxide (CMPO) during partitioning of minor actinides from high level waste (HLW) solutions

    SciTech Connect

    Mathur, J.N.; Murali, M.S.; Ruikar, P.B.; Nagar, M.S.; Sipahimalani, A.T.; Bauri, A.K.; Banerji, A.

    1998-10-01

    The radiolytic degradation of the extractant mixture 0.2 M octylphenyl-N,N{prime}-diisobutylcarbamoylmethyl phosphine oxide (CMPO) + 1.2 M tributyl phosphate in n-dodecane [to be utilized for the partitioning of minor actinides from high level waste (HLW) solutions of PUREX origin] has been investigated in contact with 3 M HNO{sub 3} or synthetic pressurized heavy water reactors (PHWR)-HLW solution under dynamic conditions. The distribution ratios of Am, Zr, Fe and Ru with the irradiated extractant mixture at varying doses have been determined under various aqueous phase conditions and correlated with the formation of degradation products. Various cycles of loading the extractant mixture with Am from PHWR-HLW, irradiating at a fixed gamma dose, and then primary and secondary clean-up of the solvent has been carried out to illustrate its reusability during partitioning of minor actinides from actual HLW solutions. The degradation products of CMPO have been identified by employing GC and GC-MS techniques.

  14. Synthesis, structure, catalytic and calculated non-linear optical properties of cis- and trans-, mer-chlorobis(triphenyl phosphine/triphenyl arsine)-dipicolinato ruthenium III complexes

    NASA Astrophysics Data System (ADS)

    Trivedi, Manoj; Nagarajan, R.; Kumar, Abhinav; Singh, Narendra K.; Rath, Nigam P.

    2011-05-01

    The new mononuclear Ru III complexes cis-, mer-[Ru( k3-dipic)(EPh 3) 2Cl]·2H 2O (E = P ( 1), As ( 2)), (L = 2,6-pyridyldicarboxylate; dipic) have been synthesized and characterized. The X-ray crystal structure of 1 reveals that the coordination geometry around the Ru III center is distorted octahedral in which three sites are occupied by tridentate dipic ligand and remaining three sites are occupied by two mutually cis triphenyl phosphine ligands and one chloride ions. In chloroform solvent, cis-, mer-[Ru( k3-dipic)(EPh 3) 2Cl]·2H 2O (E = P ( 1), As ( 2)) complexes undergoes thermal rearrangement to more stable trans-, mer-[Ru( k3-dipic)(EPh 3) 2Cl] (E = P( 3), As( 4)) complexes. Complexes 1 and 2 show rhombic EPR spectral features, while complex 3 and 4 show tetragonal distortion. The new Ru III complexes 1 and 2 display both Ru III-Ru II reduction and Ru III-Ru IV oxidation processes. These geometric isomers exhibit textbook differences both in spectroscopic as well as structural properties in the solid state. The new complexes 1 and 2 were found to catalyze the oxidation of alcohols to carbonyl derivatives using N-methyl morpholine- N-oxide as co-oxidant. The first static hyperpolarizability ( β) for all of the complexes have been investigated by density functional theory (DFT) which suggests β value increases from trans to cis form. Also, the solvent-induced effects on the non-linear optical properties (NLO) were studied by using self-consistent reaction field (SCRF) method. As the solvent polarity increases, the β value increases monotonically. The electronic absorption bands of 1 have been assigned by time dependent density functional theory (TD-DFT).

  15. 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.

  16. 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

  17. Oligo-nuclear silver thiocyanate complexes with monodentate tertiary phosphine ligands, including novel 'cubane' and 'step' tetramer forms of AgSCN : PR3 (1:1)4.

    PubMed

    Bowmaker, Graham A; Di Nicola, Corrado; Effendy; Hanna, John V; Healy, Peter C; King, Scott P; Marchetti, Fabio; Pettinari, Claudio; Robinson, Ward T; Skelton, Brian W; Sobolev, Alexandre N; Tăbăcaru, Aurel; White, Allan H

    2013-01-01

    Adducts of a number of tertiary pnicogen ligands ER(3) (triphenyl-phosphine and -arsine (PPh(3),AsPh(3)), diphenyl,2-pyridylphosphine (PPh(2)py), tris(4-fluorophenyl)phosphine (P(C(6)H(4)-4F)(3)), tris(2-tolyl)phosphine (P(o-tol)(3)), tris(cyclohexyl)phosphine (PCy(3))), with silver(I) thiocyanate, AgSCN are structurally and spectroscopically characterized. The 1:3 AgSCN : ER(3) complexes structurally defined (for PPh(3),AsPh(3) (diversely solvated)) take the form [(R(3)E)(3)AgX], the thiocyanate X = NCS being N-bound, thus [(Ph(3)E)Ag(NCS)]. A 1:2 complex with PPh(2)py, takes the binuclear form [(pyPh(2)P)(2)Ag()Ag(PPh(2)py)(2)] with an eight-membered cyclic core. 1:1 complexes are defined with PPh(2)py, P(o-tol)(3) and PCy(3); binuclear forms [(R(3)P)Ag()Ag(PR(3))] are obtained with P(o-tol)(3) (two polymorphs), while novel isomeric tetranuclear forms, which may be envisaged as dimers of dimers, are obtained with PPh(2)py, and, as further polymorphs, with PCy(3); these latter may be considered as extensions of the 'cubane' and 'step' forms previously described for [(R(3)E)AgX](4) (X = halide) complexes. Solvent-assisted mechanochemical or solvent-assisted solid-state synthesis methods were employed in some cases, where complexes could not be obtained by conventional solution methods, or where such methods yielded a mixture of polymorphs unsuitable for solid-state spectroscopy. The wavenumbers of the ν(CN) bands in the IR spectra are in broad agreement with the empirical rule that distinguishes bridging from terminal bonding, but exceptions occur for compounds that have a double SCN bridged dimeric structure, and replacement of PPh(3) with PPh(2)py apparently causes a significant decrease in ν(CN) to well below the range expected for bridging SCN in these structures. (31)P CP MAS NMR spectra yield additional parameters that allow a correlation between the structures and spectra.

  18. Synthesis and structural characterization of PHP[(C(5)Me(4))(2)], a monodentate chiral phosphine derived from intramolecular C-C coupling of tetramethylcyclopentadienyl groups: an evaluation of steric and electronic properties.

    PubMed

    Shin, J H; Bridgewater, B M; Churchill, D G; Parkin, G

    2001-10-22

    The chiral monodentate phosphine PhP[(C(5)Me(4))(2)] is readily obtained by oxidation of the lithium complex Li(2)[PhP(C(5)Me(4))(2)] with I(2), which couples the two cyclopentadienyl groups to form a five-membered heterocyclic ring. The steric and electronic properties of PhP[(C(5)Me(4))(2)] have been evaluated by X-ray diffraction and IR spectroscopic studies on a variety of derivatives, including Ph[(C(5)Me(4))(2)]PE (E = S, Se), Cp*MCl(4)[P[(C(5)Me(4))(2)]Ph] (M = Mo, Ta), Ir[P[(C(5)Me(4))(2)]Ph](2)(CO)Cl, and CpFe(CO)[PhP[(C(5)Me(4))(2)

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

    PubMed Central

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

    2010-01-01

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

  20. Catalytic dimerization of propene by nickel-phosphine complexes in 1-butyl-3-methylimidazolium chloride/AlEt{sub x}Cl{sub 3{minus}x} (x = 0, 1) ionic liquids

    SciTech Connect

    Chauvin, Y.; Einloft, S.; Olivier, H.

    1995-04-01

    The dimerization of propene was catalyzed by cationic nickel complexes in a two-phase solvent system using organochloroaluminate ionic liquids as the solvent for the catalyst. In ionic liquids containing an excess of strongly coordinating chloride ions, i.e., basic, no activity was observed. In contrast, melts containing an excess of alkylchloroaluminum species, i.e., acidic, stabilized the active cationic nickel species. The reaction products separate as an organic layer. Molecular organochloroaluminum species were extracted, and the composition of the salt was strongly modified. This was circumvented using a salt which contains an excess of aluminum chloride. The propene dimers obtained by this way can be transformed either into ethers or into alkanes to produce high octane number additives for gasoline. The effects of phosphine ligands coordinated on nickel and operating variables were investigated in order to maximize the octane number of the corresponding alkanes and ethers.

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

    SciTech Connect

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

    1994-06-29

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

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

    SciTech Connect

    Bhattacharyya, Swarnendu Domcke, Wolfgang; Dai, Zuyang

    2015-11-21

    A diabatic three-sheeted six-dimensional potential-energy surface has been constructed for the ground state and the lowest excited state of the PH{sub 3}{sup +} 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 PH{sub 3}{sup +} is dominated by the exceptionally strong Jahn-Teller coupling of the asymmetric bending vibrational mode together with a hyperline of conical intersections with the electronic ground state induced by the umbrella mode. Time-dependent population probabilities have been computed for the three adiabatic electronic states. The non-adiabatic Jahn-Teller dynamics within the excited state takes place within ≈5 fs. Almost 80% of the excited-state population decay to the ground state within about 10 fs. The wave packets become highly complex and delocalized after 20 fs and no further significant transfer of electronic population seems to occur up to 100 fs propagation time.

  3. Unraveling the formation of HCPH(X2A') molecules in extraterrestrial environments: crossed molecular beam study of the reaction of carbon atoms, C(3Pj), with phosphine, PH3(X1A1).

    PubMed

    Guo, Y; Gu, X; Zhang, F; Sun, B J; Tsai, M F; Chang, A H H; Kaiser, R I

    2007-05-01

    The reaction between ground state carbon atoms, C(3P(j)), and phosphine, PH3(X(1)A1), was investigated at two collision energies of 21.1 and 42.5 kJ mol(-1) using the crossed molecular beam technique. The chemical dynamics extracted from the time-of-flight spectra and laboratory angular distributions combined with ab initio calculations propose that the reaction proceeds on the triplet surface via an addition of atomic carbon to the phosphorus atom. This leads to a triplet CPH3 complex. A successive hydrogen shift forms an HCPH2 intermediate. The latter was found to decompose through atomic hydrogen emission leading to the cis/trans-HCPH(X(2)A') reaction products. The identification of cis/trans-HCPH(X(2)A') molecules under single collision conditions presents a potential pathway to form the very first carbon-phosphorus bond in extraterrestrial environments like molecular clouds and circumstellar envelopes, and even in the postplume chemistry of the collision of comet Shoemaker-Levy 9 with Jupiter.

  4. Phosphine-Catalyzed Addition/Cycloaddition Domino Reactions of β'-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 β'-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 β'-addition/[4 + 4] cycloaddition domino sequence. In this sequence, β'C of allenoate 1 is an electrophilic center, and its β'C and γC serve as a 1,4-dipole. When the other reaction partner is switched to 2-acyl-3-(2-pyrrole)-acrylonitrile 8, a γ-addition/[3 + 2] cycloaddition domino reaction is instead observed, in which allenoate 1 exhibits dual electrophilic reactivity of γC and 1,3-dipole chemical behavior of βC and β'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.

  5. Vibrational study of new Pt(II) and Pd(II) complexes with functionalized nitrogen-containing tertiary phosphine oxides. Ab initio study of ortho-, meta- and para-dimethylphosphinylmethyleneoxyaniline.

    PubMed

    Trendafilova, N; Bauer, G; Georgieva, I; Tosheva, T; Varbanov, S

    2003-01-01

    Vibrational study of new Pt(II) and Pd(II) complexes of functionalized nitrogen-containing tertiary phosphine oxides, namely ortho-, meta- and para-dimethylphosphinylmethyleneoxyaniline (o-, m- and p-dpmoa), (CH3)2P(O)CH2OC6H4NH2, have been presented. Geometry optimization of the ligands was performed at HF/6-31G* and B3LYP/6-31G* levels of the theory. Harmonic frequencies were calculated at HF/6-31G* optimized geometries. Relative gas-phase and solution-phase (H2O and CH3CN) basicities of o-, m- and p-dpmoa ligands have been determined by ab initio calculations at STO-3G level with the Onsager reaction field model. On the basis of the vibrational study, physical and analytical data it was suggested that the ligands in the complexes studied coordinate through the amino group and form square-planar platinum and palladium complexes of the general formula ML2Cl2 (M = Pt, Pd, L = o-, m- and p-dpmoa).

  6. Decacarbonyl-1κ3 C,2κ3 C,3κ4 C-bis­[tris­(3-chloro­phen­yl)phosphine]-1κP,2κP-triangulo-triruthenium(0) monohydrate

    PubMed Central

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

    2010-01-01

    The asymmetric unit of the title triangulo-triruthenium compound, [Ru3(C18H12Cl3P)2(CO)10]·H2O, consists of one triangulo-triruthenium complex and one disordered water solvent molecule. Two of the 3-chloro­phenyl rings are disordered over two positions with refined site occupancies of 0.671 (3)/0.329 (3) and 0.628 (3)/0.372 (3). The water mol­ecule is disordered over two positions with refined site occupancies of 0.523 (7) and 0.477 (7). Two equatorial carbonyl groups have been substituted by the two monodentate phosphine ligands, leaving one equatorial and two axial carbonyl substituents on the two Ru atoms. The remaining Ru atom carries two equatorial and two axial terminal carbonyl ligands. In the crystal structure, mol­ecules are linked into columns along the a axis by inter­molecular C—H⋯Cl and C—H⋯O hydrogen bonds. The mol­ecular structure is stabilized by weak intra­molecular C—H⋯O hydrogen bonds. PMID:21579061

  7. Technetium electrochemistry. 3. Spectroeletrochemical studies on the mixed-ligand technetium(III) complexes trans-(Tc(PR/sub 2/R')/sub 2/L)/sup +/ where L is a tetradentate Schiff base ligand and PR/sub 2/R' is a monodentate tertiary phosphine ligand

    SciTech Connect

    Ichimura, A.; Heineman, W.R.; Deutsch, E.

    1985-07-03

    The redox chemistry of a series of eight well-characterized, robust, cationic technetium(III) complexes has been investigated in propylene carbonate by using spectroelectrochemistry with a gold minigrid optically transparent thin-layer electrode. The complexes undergo a reversible 1-equiv reduction of Tc(III) to Tc(II) and a reversible 1-equiv oxidation of Tc(III) to Tc(IV). E/sup 0/' values for the Tc(III)/Tc(II) couple range from -1.11 to -0.69 V (vs. Ag/AgCl/NaCl (3 M)) while E/sup 0/' values for the Tc(IV/Tc(III) couple range from + 0.62 to + 0.79 V (vs. the same reference). The difference between E/sup 0/' /sub IV/III/ and E/sup 0/'/sub III/II/ ranges from 1.5 to 1.75 V, reflecting the large range of stability of the Tc(III) state. The formal potentials of both redox processes depend on the nature of the phosphine and Schiff base ligands. These dependencies are readily explained in terms of ..pi.. back-bonding from low-valent technetium to both the phosphine and Schiff base ligands. All the technetium complexes, including the electrogenerated Tc(II) and Tc(IV) species, exhibit characteristic metal-to-ligand charge-transfer (MTLCT) bands in the visible region of the spectrum. The energies of these MTLCT tranisitions are a function of the oxidation state of the technetium, the nature of the phosphine ligands, and the nature of the Schiff base ligand. The energy of the Tc(III) MTLCT band is linearly related to the redox potential of the Tc(IV)/Tc(III) couple.

  8. Isomer dependence in the assembly and lability of silver(I) trifluoromethanesulfonate complexes of the heteroditopic ligands, 2-, 3-, and 4-[di(1H-pyrazolyl)methyl]phenyl(di-p-tolyl)phosphine.

    PubMed

    Gardinier, James R; Hewage, Jeewantha S; Lindeman, Sergey V

    2014-11-17

    Three isomers of a new heteroditopic ligand that contains a di(1H-pyrazolyl)methyl (-CHpz2) moiety connected to a di(p-tolyl)phosphine group via a para-, meta-, or ortho-phenylene spacer (pL, mL, and oL, respectively) have been synthesized by using a palladium(0)-catalyzed coupling reaction between HP(p-tolyl)2 and the appropriate isomer of (IC6H4)CHpz2. The 1:1 complexes of silver(I) trifluoromethanesulfonate, Ag(OTf), were prepared to examine the nature of ligand coordination and the type of supramolecular isomer (monomeric, cyclic oligomeric, or polymeric) that would be obtained. The single crystal X-ray diffraction studies showed that [Ag(pL)](OTf), 1, and [Ag(mL)](OTf), 2, possessed cyclic dimeric dications, whereas [Ag(oL)](OTf), 3, was a coordination polymer. The polymeric chain in 3 could be disrupted by reaction with triphenylphosphine, and the resulting complex, [Ag(oL)(PPh3)](OTf), 4, possessed a monometallic cation where the ligand was bound to silver in a chelating κ(2)P,N- coordination mode. The solution structures of 1-4 were probed via a combination of IR, variable-temperature multinuclear ((1)H, (13)C, (31)P) NMR spectroscopy, as well as by electron spray ionization (ESI)(+) mass spectrometry. A related complex [Ag(m-IC6H4CHpz2)2](OTf), 5, was also prepared, and its solid-state and solution spectroscopic properties were studied for comparison purposes. These studies suggest that the cyclic structures of 1 and 2 are likely preserved but are dynamic in solution at room temperature. Moreover, both 3 and 4 have dynamic solution structures where 3 is likely extensively dissociated in CH3CN or acetone rather than being polymeric as in the solid state.

  9. Bioinspired Hydrogenase Models: The Mixed-Valence Triiron Complex [Fe3(CO)7(μ-edt)2] and Phosphine Derivatives [Fe3(CO)7–x(PPh3)x(μ-edt)2] (x = 1, 2) and [Fe3(CO)5(κ2-diphosphine)(μ-edt)2] as Proton Reduction Catalysts

    PubMed Central

    2014-01-01

    The mixed-valence triiron complexes [Fe3(CO)7–x(PPh3)x(μ-edt)2] (x = 0–2; edt = SCH2CH2S) and [Fe3(CO)5(κ2-diphosphine)(μ-edt)2] (diphosphine = dppv, dppe, dppb, dppn) have been prepared and structurally characterized. All adopt an anti arrangement of the dithiolate bridges, and PPh3 substitution occurs at the apical positions of the outer iron atoms, while the diphosphine complexes exist only in the dibasal form in both the solid state and solution. The carbonyl on the central iron atom is semibridging, and this leads to a rotated structure between the bridged diiron center. IR studies reveal that all complexes are inert to protonation by HBF4·Et2O, but addition of acid to the pentacarbonyl complexes results in one-electron oxidation to yield the moderately stable cations [Fe3(CO)5(PPh3)2(μ-edt)2]+ and [Fe3(CO)5(κ2-diphosphine)(μ-edt)2]+, species which also result upon oxidation by [Cp2Fe][PF6]. The electrochemistry of the formally Fe(I)–Fe(II)–Fe(I) complexes has been investigated. Each undergoes a quasi-reversible oxidation, the potential of which is sensitive to phosphine substitution, generally occurring between 0.15 and 0.50 V, although [Fe3(CO)5(PPh3)2(μ-edt)2] is oxidized at −0.05 V. Reduction of all complexes is irreversible and is again sensitive to phosphine substitution, varying between −1.47 V for [Fe3(CO)7(μ-edt)2] and around −1.7 V for phosphine-substituted complexes. In their one-electron-reduced states, all complexes are catalysts for the reduction of protons to hydrogen, the catalytic overpotential being increased upon successive phosphine substitution. In comparison to the diiron complex [Fe2(CO)6(μ-edt)], [Fe3(CO)7(μ-edt)2] catalyzes proton reduction at 0.36 V less negative potentials. Electronic structure calculations have been carried out in order to fully elucidate the nature of the oxidation and reduction processes. In all complexes, the HOMO comprises an iron–iron bonding orbital localized between the two iron

  10. New silylated iminophosphorano(amino)phosphines Me(3)SiN=PPh(2)N(R)PPh(2) (R = Et, (n)Pr, (n)Bu). Crystal and molecular structure of trimethylsilyliminophosphorano(propylamino)diphenylphosphine Me(3)SiN=PPh(2)N((n)Pr)PPh(2). Further oxidative derivatization with S, Se, and azides, titanium(IV) transmetalation of the imine, and syntheses of rhodium(I), palladium(II), and platinum(II) complexes of these iminophosphorano(amino)phosphines.

    PubMed

    Balakrishna, M S; Teipel, S; Pinkerton, A A; Cavell, R G

    2001-04-01

    Bis(phosphino)amines Ph(2)PN(R)PPh(2) (R = Et, (n)Pr, (n)Bu) react with stoichiometric amounts of trimethylsilyl azide to give the trimethylsilyliminophosphorano(amino)phosphines Me(3)SiN=PPh(2)N(R)PPh(2) (1, R = Et; 2, R = (n)Pr; 3, R = (n)Bu) as crystalline compounds. The structure of 2 has been determined by single-crystal X-ray analysis. (Crystal data for 2: monoclinic, P2(1)/c, a = 10.235(1) A, b = 16.802(2) A, c = 17.075(2) A, beta = 101.05(1) degrees, V = 2882.9(5) A(3), Z = 4.) The structure of 2, which is the first example of an iminophosphoranophosphine with the P(III)-N-P(V)=N skeleton, was solved by direct methods and refined to R = 0.044. Compound 2 readily reacts with elemental sulfur, selenium, or phosphoryl azide to give fully oxidized phosphinimines Ph(2)P(E)N((n)()Pr)Ph(2)P=NSiMe(3) (4, E = S; 5, E = Se; 6, E = NP(O)(OPh)(2)). Compounds 4-6 are very sensitive to moisture and readily undergo desilylation to give the parent phosphinimines Ph(2)P(E)N((n)()Pr)Ph(2)P=NH, which can be isolated as moderately stable crystalline solids. The phosphiniminophosphine 2 and the oxidized phosphinimines (4 and 5) react with CpTiCl(3) to give new nitrogen-bound Ti(IV) derivatives Ph(2)P(E)N((n)Pr)Ph(2)P=NTi(Cp)Cl(2) (10, E = lone pair; 11, E = S; 12, E = Se). Compounds 1-3 readily react with rhodium(I), palladium(II), and platinum(II) complexes to give five-membered metallacycles via phosphorus(III) and imine nitrogen coordination. PMID:11312734

  11. 40 CFR 721.6020 - Phosphine, dialkylyphenyl.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... with information on the location and availability of MSDSs does not apply when an MSDS is not required under § 721.72(c). The provision of § 721.72(g) requiring placement of specific information in an MSDS does not apply when an MSDS is not required under § 721.72(c). (iii) Disposal. Requirements...

  12. 40 CFR 721.6020 - Phosphine, dialkylyphenyl.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... with information on the location and availability of MSDSs does not apply when an MSDS is not required under § 721.72(c). The provision of § 721.72(g) requiring placement of specific information in an MSDS does not apply when an MSDS is not required under § 721.72(c). (iii) Disposal. Requirements...

  13. 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...

  14. 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...

  15. 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...

  16. 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

  17. Superatomic S(2) silver clusters stabilized by a thiolate-phosphine monolayer: insight into electronic and optical properties of Ag14(SC6H3F2)12(PPh3)8 and Ag16(SC6H3F2)14(DPPE)4.

    PubMed

    Gell, Lars; Lehtovaara, Lauri; Häkkinen, Hannu

    2014-09-18

    The electronic structure of two recently crystallographically solved, thiolate-phosphine protected silver clusters Ag14 and Ag16 are analyzed via density functional theory (DFT) and their optical excitations are analyzed from time-dependent DFT perturbation theory. Both clusters can be characterized as having the S(2) free-electron configuration in the metal core, which is the first time such a configuration is confirmed for structurally known ligand-protected noble metal clusters. However, their different core shapes and ligand layer induce significantly different optical spectra. Performance of gradient-corrected DFT functionals is discussed and it is shown that the asymptotically correct Leeuwen-Baerends LB94 functional reproduces the optical spectrum of Ag14 in a good agreement with experiment. Choice of the functional becomes important for clusters where the optical transitions are dominated by the electron-rich ligand layer.

  18. Synthetic, thermochemical, and catalytic studies of fluorinated tertiary phosphine ligands R{sub 2}PR{sub f} [R = Cy, Ph, {sup i}Pr; R{sub f} = CH{prime}{sub 2}CH{sub 2}(CF{sub 2}){sub 5}CF{sub 3}] in rhodium systems

    SciTech Connect

    Smith, D.C. Jr.; Stevens, E.D.; Nolan, S.P.

    1999-11-15

    The fluoroalkylphosphine compounds PR{sub 2}R{sub f} (R = Cy (1); {sup i}Pr (2); R{sub f} = CH{sub 2}CH{sub 2}(CF{sub 2}){sub 5}CF{sub 3}) have been prepared from the reactions of the Grignard reagent IMgR{sub f} and appropriate ClPR{sub 2} (R = Cy, {sup i}PR). The fluorinated phosphine ligands [PR{sub 2}R{sub f} (R = Cy) (1); {sup i}Pr (2); Ph (3); R{sub f} = CH{sub 2}CH{sub 2}(CF{sub 2}){sub 5}CF{sub 3}] react with [Rh(CO){sub 2}Cl]{sub 2} to yield the corresponding [Rh(CO)Cl(PR{sub 2}R{sub f}){sub 2}] (R = Cy) (4); {sup i}Pr (5); Ph (6) complexes. Infrared studies on the carbonyl complexes and solution calorimetry studies of the reaction of [Rh(CO){sub 2}Cl]{sub 2} with PR{sub 2}R{sub f} (R = Ph, {sup i}Pr, Cy) have been used to quantify the relative ligand donor strength for the series: PCy{sub 2}R{sub f} {approx} P{sup i}Pr{sub 2}R{sub f} {gt} PPh{sub 2}R{sub f}. The solid-state crystal structure of [Rh(CO)Cl(PPh{sub 2}R{sub f}){sub 2}] (6) is reported. Additionally, these partially fluorinated phosphine ligands (1 and 3) can be used as supporting ligation in rhodium-mediated hydrogenation reactions.

  19. 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.

  20. Phosphine-free synthesis of high-quality reverse type-I ZnSe/CdSe core with CdS/Cd(x)Zn(1 - x)S/ZnS multishell nanocrystals and their application for detection of human hepatitis B surface antigen.

    PubMed

    Shen, Huaibin; Yuan, Hang; Niu, Jin Zhong; Xu, Shasha; Zhou, Changhua; Ma, Lan; Li, Lin Song

    2011-09-16

    Highly photoluminescent (PL) reverse type-I ZnSe/CdSe nanocrystals (NCs) and ZnSe/CdSe/CdS/Cd(x)Zn(1 - x)S/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/Cd(x)Zn(1 - x)S/ZnS NCs were synthesized in a large scale synthesis. After the overgrowth of a CdS/Cd(x)Zn(1 - x)S/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/Cd(x)Zn(1 - x)S/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/Cd(x)Zn(1 - x)S/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). PMID:21852741

  1. 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

  2. Development of an extractive spectrophotometric method for estimation of uranium in ore leach solutions using 2-ethylhexyl phosphonic acid-mono-2-ethylhexyl ester (PC88A) and tri-n-octyl phosphine oxide (TOPO) mixture as extractant and 2-(5-bromo-2-pyridylozo)-5-diethyl aminophenol (Br-PADAP) as chromophore.

    PubMed

    Biswas, Sujoy; Pathak, P N; Roy, S B

    2012-06-01

    An extractive spectrophotometric analytical method has been developed for the determination of uranium in ore leach solution. This technique is based on the selective extraction of uranium from multielement system using a synergistic mixture of 2-ethylhexyl phosphonic acid-mono-2-ethylhexyl ester (PC88A) and tri-n-octyl phosphine oxide (TOPO) in cyclohexane and color development from the organic phase aliquot using 2-(5-Bromo-2-pyridylazo)-5-diethyl aminophenol (Br-PADAP) as chromogenic reagent. The absorption maximum (λ(max)) for UO(2)(2+)-Br-PADAP complex in organic phase samples, in 64% (v/v) ethanol containing buffer solution (pH 7.8) and 1,2-cyclohexylenedinitrilotetraacetic acid (CyDTA) complexing agent, has been found to be at 576 nm (molar extinction coefficient, ɛ: 36,750 ± 240 L mol(-1)cm(-1)). Effects of various parameters like stability of complex, ethanol volume, ore matrix, interfering ions etc. on the determination of uranium have also been evaluated. Absorbance measurements as a function of time showed that colored complex is stable up to > 24h. Presence of increased amount of ethanol in colored solution suppresses the absorption of a standard UO(2)(2+)-Br-PADAP solution. Analyses of synthetic standard as well as ore leach a solution show that for 10 determination relative standard deviation (RSD) is < 2%. The accuracy of the developed method has been checked by determining uranium using standard addition method and was found to be accurate with a 98-105% recovery rate. The developed method has been applied for the analysis of a number of uranium samples generated from uranium ore leach solutions and results were compared with standard methods like inductively coupled plasma emission spectrometry (ICPAES). The determined values of uranium concentrations by these methods are within ± 2%. This method can be used to determine 2.5-250 μg mL(-1) uranium in ore leach solutions with high accuracy and precision. PMID:22381794

  3. 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 ...

  4. Computer-aided optimization of phosphinic inhibitors of bacterial ureases.

    PubMed

    Vassiliou, Stamatia; Kosikowska, Paulina; Grabowiecka, Agnieszka; Yiotakis, Athanasios; Kafarski, Paweł; Berlicki, Lukasz

    2010-08-12

    Urease inhibitors can be considered as a tool to control the damaging effect of ureolytic bacteria infections in humans which occur commonly in the developed countries. Computer-aided optimization of the aminomethylphosphinate structures by modifying both their N- and P-termini led to the invention of a novel group of inhibitors of bacterial ureases. Introduction of P-hydroxymethyl group into the molecule resulted in considerable increase of the inhibitory activity against enzymes purified from Bacillus pasteurii and Proteus vulgaris as compared with their P-methyl counterparts described previously. The designed compounds represent a competitive reversible class of urease inhibitors. The most potent, N-methyl-aminomethyl-P-hydroxymethylphosphinic acid, displayed K(i) = 360 nM against P. vulgaris enzyme. PMID:20684601

  5. 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.

  6. Latitudinal variability of arsine, germane and phosphine in Jupiter's troposphere

    NASA Astrophysics Data System (ADS)

    Giles, Rohini Sara; Fletcher, Leigh N.; Irwin, Patrick Gerard Joseph

    2016-10-01

    High-resolution 5-μm observations of Jupiter from the CRIRES instrument at the Very Large Telescope are used to measure latitudinal variability in AsH3, GeH4 and PH3. The 5-micron region is a spectral window allowing us to probe down to Jupiter's middle troposphere (4-8 bar). CRIRES observations in 2012 and 2013 provide high-resolution (R=96,000) latitudinally-resolved spectra in the 4.7-5.2 μm region. In the middle troposphere, AsH3, GeH4and PH3 are disequilibrium species that are only present because of rapid upwelling from deeper regions of the planet. Their observed abundances depend on the chemical lifetimes, the strength of the vertical mixing and the rate of photolytic destruction, and are therefore likely to vary with latitude. We analyse the CRIRES observations using the NEMESIS radiative transfer code and retrieval algorithm in order to search for any latitudinal variability in the disequilibrium species. We find that there is a significant degeneracy between the retrieved gaseous abundances and the cloud structure – specifically, the scattering properties of the main tropospheric cloud deck, and the presence/absence of an additional deep cloud. Because of these degeneracies, there is no clear evidence for any variability in GeH4. However, for AsH3 and PH3, there are significant latitudinal differences in the observed lineshape that cannot be accounted for by clouds. We conclude that both of these gases show an enhancement at high latitudes. In the case of AsH3, the retrieved abundance varies from subsolar in the equatorial regions (as seen in previous studies) to supersolar in the polar regions. Our findings are in contrast with the theoretical simulations of Wang et al. (2016, doi:10.1016/j.icarus.2016.04.027), which predict that AsH3 and PH3 should not vary with latitude, and that GeH4 should decrease in abundance at high latitudes.

  7. 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.

  8. 40 CFR 180.225 - Phosphine; tolerances for residues.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    .... Commodity Parts per million Almond 0.1 Avocado 0.01 Banana 0.01 Barley, grain 0.1 Cabbage, Chinese, bok choy 0.01 Cabbage, Chinese, napa 0.01 Cacao bean, dried bean 0.1 Cashew 0.1 Citron, citrus 0.01...

  9. 40 CFR 180.225 - Phosphine; tolerances for residues.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    .... Commodity Parts per million Almond 0.1 Avocado 0.01 Banana 0.01 Barley, grain 0.1 Cabbage, Chinese, bok choy 0.01 Cabbage, Chinese, napa 0.01 Cacao bean, dried bean 0.1 Cashew 0.1 Citron, citrus 0.01...

  10. 40 CFR 180.225 - Phosphine; tolerances for residues.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    .... Commodity Parts per million Almond 0.1 Avocado 0.01 Banana 0.01 Barley, grain 0.1 Cabbage, Chinese, bok choy 0.01 Cabbage, Chinese, napa 0.01 Cacao bean, dried bean 0.1 Cashew 0.1 Citron, citrus 0.01...

  11. 40 CFR 180.225 - Phosphine; tolerances for residues.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    .... Commodity Parts per million Almond 0.1 Avocado 0.01 Banana 0.01 Barley, grain 0.1 Cabbage, Chinese, bok choy 0.01 Cabbage, Chinese, napa 0.01 Cacao bean, dried bean 0.1 Cashew 0.1 Citron, citrus 0.01...

  12. 40 CFR 180.225 - Phosphine; tolerances for residues.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    .... Commodity Parts per million Almond 0.1 Avocado 0.01 Banana 0.01 Barley, grain 0.1 Cabbage, Chinese, bok choy 0.01 Cabbage, Chinese, napa 0.01 Cacao bean, dried bean 0.1 Cashew 0.1 Citron, citrus 0.01...

  13. Nitrogen fixation revisited on iron(0) dinitrogen phosphine complexes.

    PubMed

    Field, Leslie D; Hazari, Nilay; Li, Hsiu L

    2015-05-18

    A reinvestigation of the treatment of [Fe(N2)(PP)2] (PP = depe, dmpe) with acid revealed no ammonium formation. Instead, rapid protonation at the metal center to give hydride complexes was observed. Treatment of [Fe(N2)(dmpe)2] with methylating agents such as methyl triflate or methyl tosylate resulted in methylation of the metal center to afford [FeMe(N2)(dmpe)2](+). Treatment of [Fe(N2)(dmpe)2] with trimethylsilyl triflate, however, resulted in reaction at dinitrogen affording NH4(+) on subsequent treatment with acid. The side-on bound hydrazine complex [Fe(N2H4)(dmpe)2](2+) and bis(ammonia) complex [Fe(NH3)2(dmpe)2](2+) were identified by (15)N NMR spectroscopy as other species formed in the reaction mixture.

  14. 2-Amino­pyridinium diphenyl­phosphinate monohydrate

    PubMed Central

    Nazari, Mohammad; Abbasi, Alireza; Nemati Kharat, Ali; Hantehzadeh, Mohammad Reza

    2009-01-01

    In the crystal of the title hydrated salt, C5H7N2 +·C12H10O2P−·H2O, the cations, anions and water mol­ecules connected by N—H⋯O and O—H⋯O hydrogen bonds into a layer along the bc plane; the phenyl rings protrude into the space between the layers. The dihedral angle between rings of anion is 86.1 (1)°. PMID:21577689

  15. 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…

  16. Quantitative prediction and interpretation of vibrational spectra of organo-phosphorus compounds. Part I. Phosphine oxide (H 3PO) and phosphinous acid (H 2POH)

    NASA Astrophysics Data System (ADS)

    Person, Willis B.; Kwiatkowski, Jozef S.; Bartlett, Rodney J.

    1987-03-01

    Ab initio SCF predictions of the IR spectra of H 3PO and H 2POH in its two isomeric forms are reported. These are compared with recent matrix isolation experimental results. For these systems, the SCF results in polarized basis sets are believed to be sufficiently accurate to suggest that the cis form of H 2POH was that observed in the matrix rather than the trans form. The mean error in the scaled predicted frequencies for H 3PO is 11 cm -1, while the computed intensities accurately reflect the observed trends. A preliminary interpretation of the intensity results is begun, with an ultimate goal of full understanding of the IR intensities of these phosphorus compounds.

  17. Coriolis Interactions in the nu2, nu4a, nu4b, and nu3a States of Phosphine-d1

    PubMed

    Kshirsagar; Job

    1997-10-01

    Spectra of the nu4a (HPH bend) and nu4b (HPD bend) bands of the PH2D molecule have been recorded and analyzed. The Coriolis interactions between the two states as well as the various Coriolis interactions of the nu4a and nu4b states with the nu2 state have been included in the analysis. Several new assignments of transitions which occur with enhanced intensity in the nu2 band also have been made. The parameters of the nu4a and nu4b states, improved parameters of the nu2 state, and the interaction parameters have been determined. The data on the nu3a band of PH2D have been reanalyzed by taking into account the b-axis Coriolis interaction of the nu3a state with the 2nu2 state. Copyright 1997 Academic Press. Copyright 1997Academic Press

  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. Chiral Phosphinate Degradation by the Fusarium Species: Scope and Limitation of the Process

    PubMed Central

    Brzezińska-Rodak, Małgorzata

    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 30°C, but F. culmorum required 10 days and F. oxysporum 11 days to accomplish the process, which was continuously monitored using the 31P NMR technique. PMID:24324893

  20. Phosphine-triggered co-catenation of :BR and CO on an iron atom.

    PubMed

    Braunschweig, Holger; Ye, Qing; Vargas, Alfredo; Radacki, Krzysztof; Damme, Alexander

    2013-09-27

    The chain gang: By treatment of an iron bis(borylene) complex with PCy3 and subsequent stepwise substitution of a CO ligand by PMe3 , a catenated 1D OC-B-B-CO chain was generated in the coordination sphere of iron. This is an CO analogue of the recently reported 1D B-B-B-B chain in the iron tetraboron complex [(OC)2Fe{BN(SiMe3)2}2(BDur)2]. Dur=2,3,5,6-tetramethylphenyl. PMID:24038997

  1. 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…

  2. Solid Molecular Phosphine Catalysts for Formic Acid Decomposition in the Biorefinery.

    PubMed

    Hausoul, Peter J C; Broicher, Cornelia; Vegliante, Roberta; Göb, Christian; Palkovits, Regina

    2016-04-25

    The co-production of formic acid during the conversion of cellulose to levulinic acid offers the possibility for on-site hydrogen production and reductive transformations. Phosphorus-based porous polymers loaded with Ru complexes exhibit high activity and selectivity in the base-free decomposition of formic acid to CO2 and H2 . A polymeric analogue of 1,2-bis(diphenylphosphino)ethane (DPPE) gave the best results in terms of performance and stability. Recycling tests revealed low levels of leaching and only a gradual decrease in the activity over seven runs. An applicability study revealed that these catalysts even facilitate selective removal of formic acid from crude product mixtures arising from the synthesis of levulinic acid.

  3. Prebiotic Potential of Reduced Oxidation State Phosphorus. The H-Phosphinate-Pyruvate System

    NASA Astrophysics Data System (ADS)

    Bryant, D. E.; Marriott, K. E. R.; MacGregor, S. A.; Fishwick, C. W. G.; Kilner, C.; Bullough, E. K.; Pasek, M. A.; Kee, T. P.

    2010-04-01

    Phosphorus (P) is central to life as we know it but problems with using geologically available orthophosphate en route to life remain. Here we discuss how reduced oxidation state P-chemistry may offer additional possibilities for prebiotic chemistry.

  4. (2,4-Dihydroxy­benzyl­idene)dimethyl­ammonium dichloro­phosphinate

    PubMed Central

    Xu, Hai-Jun; Tan, Qing-Yin; Pang, Yi-Jie

    2009-01-01

    In the title compound, C9H12NO2 +·Cl2PO2 −, the mol­ecular skeleton of the cation is nearly planar with an r.m.s. deviation of 0.0336 Å. In the crystal structure, inter­molecular O—H⋯O hydrogen bonds link cations and anions into chains running along [10]. PMID:21581952

  5. Synthesis and characterisation of nonclassical ruthenium hydride complexes containing chelating bidentate and tridentate phosphine ligands.

    PubMed

    Prechtl, Martin H G; Ben-David, Yehoshoa; Giunta, Daniela; Busch, Stefan; Taniguchi, Yuki; Wisniewski, Wolfgang; Görls, Helmar; Mynott, Richard J; Theyssen, Nils; Milstein, David; Leitner, Walter

    2007-01-01

    The synthesis and characterisation of nonclassical ruthenium hydride complexes containing bidentate PP and tridentate PCP and PNP pincer-type ligands are described. The mononuclear and dinuclear ruthenium complexes presented have been synthesised in moderate to high yields by the direct hydrogenation route (one-pot synthesis) or in a two-step procedure. In both cases [Ru(cod)(metallyl)(2)] served as a readily available precursor. The influences of the coordination geometry and the ligand framework on the structure, binding, and chemical properties of the M--H(2) fragments were studied by X-ray crystal structure analysis, spectroscopic methods, and reactivity towards N(2), D(2), and deuterated solvents.

  6. 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.

  7. Spectroscopic parameters of phosphine, PH3, in its ground vibrational state

    NASA Astrophysics Data System (ADS)

    Müller, Holger S. P.

    2013-11-01

    The ground state rotational spectrum of PH3 has been reanalyzed taking into account recently published very accurate data from sub-Doppler and conventional absorption spectroscopy measurements as well as previous data from the radio-frequency to the far-infrared regions. These data include ΔJ=ΔK=0 transitions between A1 and A2 levels, ΔJ=0, ΔK=3 transitions as well as regular ΔJ=1, ΔK=0 rotational transitions. Hyperfine splitting caused by the 31P and 1H nuclei has been considered, and the treatment of the A1/A2 splitting has been discussed briefly. Improved spectroscopic parameters have been obtained. Interestingly, the most pronounced effects occurred for the hyperfine parameters.

  8. Borane-protected phosphines are redox-active radioprotective agents for endothelial cells

    PubMed Central

    Crowe, Megan E.; Lieven, Christopher J.; Thompson, Alex F.; Sheibani, Nader; Levin, Leonard A.

    2015-01-01

    Exposure to radiation can damage endothelial cells in the irradiated area via the production of reactive oxygen species. We synthesized phosphine–borane complexes that reduce disulfide bonds and had previously been shown to interfere with redox-mediated signaling of cell death. We hypothesized that this class of drugs could interfere with the downstream effects of oxidative stress after irradiation and rescue endothelial cells from radiation damage. Cultured bovine aortic endothelial cells were plated for clonogenic assay prior to exposure to varying doses of irradiation from a 137Cs irradiator and treated with various concentrations of bis(3-propionic acid methyl ester)phenylphosphine borane complex (PB1) at different time points. The clone-forming ability of the irradiated cells was assessed seven days after irradiation. We compared the radioprotective effects of PB1 with the aminothiol radioprotectant WR1065 and known superoxide scavengers. PB1 significantly protected bovine aortic endothelial cells from radiation damage, particularly when treated both before and after radiation. The radioprotection with 1 µM PB1 corresponded to a dose-reduction factor of 1.24. Radioprotection by PB1 was comparable to the aminothiol WR1065, but was significantly less toxic and required much lower concentrations of drug (1 µM vs. 4 mM, respectively). Superoxide scavengers were not radioprotective in this paradigm, indicating the mechanisms for both loss of clonogenicity and PB1 radioprotection are independent of superoxide signaling. These data demonstrate that PB1 is an effective redox-active radioprotectant for endothelial cells in vitro, and is radioprotective at a concentration approximately 4 orders of magnitude lower than the aminothiol WR1065 with less toxicity. PMID:26188467

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

    NASA Astrophysics Data System (ADS)

    Landman, Marilé; 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.

  10. Solvent Control of Surface Plasmon-Mediated Chemical Deposition of Au Nanoparticles from Alkylgold Phosphine Complexes.

    PubMed

    Muhich, Christopher L; Qiu, Jingjing; Holder, Aaron M; Wu, Yung-Chien; Weimer, Alan W; Wei, Wei David; McElwee-White, Lisa; Musgrave, Charles B

    2015-06-24

    Bottom-up approaches to nanofabrication are of great interest because they can enable structural control while minimizing material waste and fabrication time. One new bottom-up nanofabrication method involves excitation of the surface plasmon resonance (SPR) of a Ag surface to drive deposition of sub-15 nm Au nanoparticles from MeAuPPh3. In this work we used density functional theory to investigate the role of the PPh3 ligands of the Au precursor and the effect of adsorbed solvent on the deposition process, and to elucidate the mechanism of Au nanoparticle deposition. In the absence of solvent, the calculated barrier to MeAuPPh3 dissociation on the bare surface is <20 kcal/mol, making it facile at room temperature. Once adsorbed on the surface, neighboring MeAu fragments undergo ethane elimination to produce Au adatoms that cluster into Au nanoparticles. However, if the sample is immersed in benzene, we predict that the monolayer of adsorbed solvent blocks the adsorption of MeAuPPh3 onto the Ag surface because the PPh3 ligand is large compared to the size of the exposed surface between adsorbed benzenes. Instead, the Au-P bond of MeAuPPh3 dissociates in solution (Ea = 38.5 kcal/mol) in the plasmon heated near-surface region followed by the adsorption of the MeAu fragment on Ag in the interstitial space of the benzene monolayer. The adsorbed benzene forces the Au precursor to react through the higher energy path of dissociation in solution rather than dissociatively adsorbing onto the bare surface. This requires a higher temperature if the reaction is to proceed at a reasonable rate and enables the control of deposition by the light induced SPR heating of the surface and nearby solution.

  11. CHIRAL-AT-METAL OSMIUM(VI) PHOSPHINE COMPLEXES. (R829553)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  12. Contact doping of silicon wafers and nanostructures with phosphine oxide monolayers.

    PubMed

    Hazut, Ori; Agarwala, Arunava; Amit, Iddo; Subramani, Thangavel; Zaidiner, Seva; Rosenwaks, Yossi; Yerushalmi, Roie

    2012-11-27

    Contact doping method for the controlled surface doping of silicon wafers and nanometer scale structures is presented. The method, monolayer contact doping (MLCD), utilizes the formation of a dopant-containing monolayer on a donor substrate that is brought to contact and annealed with the interface or structure intended for doping. A unique feature of the MLCD method is that the monolayer used for doping is formed on a separate substrate (termed donor substrate), which is distinct from the interface intended for doping (termed acceptor substrate). The doping process is controlled by anneal conditions, details of the interface, and molecular precursor used for the formation of the dopant-containing monolayer. The MLCD process does not involve formation and removal of SiO(2) capping layer, allowing utilization of surface chemistry details for tuning and simplifying the doping process. Surface contact doping of intrinsic Si wafers (i-Si) and intrinsic silicon nanowires (i-SiNWs) is demonstrated and characterized. Nanowire devices were formed using the i-SiNW channel and contact doped using the MLCD process, yielding highly doped SiNWs. Kelvin probe force microscopy (KPFM) was used to measure the longitudinal dopant distribution of the SiNWs and demonstrated highly uniform distribution in comparison with in situ doped wires. The MLCD process was studied for i-Si substrates with native oxide and H-terminated surface for three types of phosphorus-containing molecules. Sheet resistance measurements reveal the dependency of the doping process on the details of the surface chemistry used and relation to the different chemical environments of the P═O group. Characterization of the thermal decomposition of several monolayer types formed on SiO(2) nanoparticles (NPs) using TGA and XPS provides insight regarding the role of phosphorus surface chemistry at the SiO(2) interface in the overall MLCD process. The new MLCD process presented here for controlled surface doping provides a simple yet highly versatile means for achieving postgrowth doping of nanometer scale structures and interfaces. PMID:23083376

  13. 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.

  14. cis-Dicyanoosmium(II) diimine complexes bearing phosphine or sulfoxide ligands: spectroscopic and luminescent studies.

    PubMed

    Lai, Siu-Wai; Chan, Queenie K-W; Zhu, Nianyong; Che, Chi-Ming

    2007-12-24

    A series of cis-dicyanoosmium(II) complexes [Os(PPh3)2(CN)2(N intersectionN)] (N intersectionN = Ph2phen (2a), bpy (2b), phen (2c), Ph2bpy (2d), tBu2bpy (2e)) and [Os(DMSO)2(CN)2(N intersectionN)] (3a-3e, N intersectionN = Br2phen (3f), Clphen (3g)), were synthesized and their spectroscopic and photophysical properties were examined, and [Os(PMe3)2(CN)2(phen)] (4) with axial PMe3 ligands was similarly prepared. The molecular structures of 2a, 2c, [2c.Zn(NO3)2]infinity, 2d, 2e, 3b, 3d, 3e, and 4 were determined by X-ray crystallographic analyses. The two CN ligands are cis to each other with mean Os-C bond distance of 2.0 A. The two PR3 (R = Ph, Me) or DMSO ligands are trans to each other with P/S-Os-P/S angles of approximately 177 degrees . The UV-vis absorption spectra of 2a-2e display an intense absorption band at 268-315 nm (epsilon = approximately (1.54-4.82) x 104 M-1 cm-1) that are attributed to pi --> pi*(N intersection N) and/or pi --> pi*(PPh3) transitions. The moderately intense absorption bands with lambdamax at 387-460 nm (epsilon = approximately (2.4-11.3) x 103 M(-1) cm(-1)) are attributed to a 1MLCT transition. A weak, broad absorption at 487-600 nm (epsilon = approximately 390-1900 M(-1) cm(-1)) is assigned to a 3MLCT transition. Excitation of 2a-2e in dichloromethane at 420 nm gives an emission with peak maximum at 654-703 nm and lifetime of 0.16-0.67 micros. The emission energies, lifetimes, and quantum yields show solvatochromic responses, and plots of numax, tau, and Phi, respectively, versus ET (solvent polarity parameter) show linear correlations, indicating that the emission is sensitive to the local environment. The broad structureless solid-state emission of 2a-2e at 298 (lambdamax 622-707 nm) and 77 (lambdamax 602-675 nm) K are assigned to 3MLCT excited states. The 77 K MeOH/EtOH (1:4) glassy solutions of 2a-2e also exhibit 3MLCT emissions with lambdamax = 560-585 nm. The 1MLCT absorption and 3MLCT emission of 3a-3g occur at lambdamax = 332-390 nm and 553-644 nm, respectively. In the presence of Zn(NO3)2, both the 1MLCT absorption and 3MLCT emission of 2c in acetonitrile blue-shift from 397 to 341 nm and 651 to 531 nm, respectively. The enhancement of emission intensity (I/Io) of 2e at 531 nm reached a maximum of approximately 810 upon the addition of two equivs of Zn(NO3)2. The crystallographic and spectroscopic evidence suggests that 2c undergoes binding of Zn2+ ions via the cyano moieties.

  15. Phosphinogold(I) dithiocarbamate complexes: effect of the nature of phosphine ligand on anticancer properties.

    PubMed

    Keter, Frankline K; Guzei, Ilia A; Nell, Margo; Zyl, Werner E van; Darkwa, James

    2014-02-17

    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

  16. A cobalt-phosphine complex as mediator in the formation of carbon-carbon bonds

    SciTech Connect

    Orsini, F.; Pelizzoni, F.; Pulici, M.

    1994-01-14

    The complex, [Co(P(CH{sub 3}){sub 3}){sub 4}], is found to mediate the Reformatsky-type reaction of halogenated esters, lactones, or amides with carbonyl compounds (ketones, aldehydes). The products of these reactions are alcohols. 15 refs., 1 tab.

  17. A porphyrin complex of Gold(I): (Phosphine)gold(I) azides as cation precursors

    PubMed Central

    Partyka, David V.; Robilotto, Thomas J.; Zeller, Matthias; Hunter, Allen D.; Gray, Thomas G.

    2008-01-01

    A silver- and Brönsted acid-free protocol for generating the (tricyclohexylphosphine)gold(I) cation from the corresponding azide complexes is disclosed. The gold(I) cations so liberated are trapped by complexation with octaethylporphyrin. The first structurally authenticated gold(I) porphyrin complex crystallizes with formula C72H112Au2F12N4P2Sb2, space group C2/c, a = 21.388 (4), b = 19.679 (4), c = 19.231 (3) Å; β = 111.030 (3)°. Solution spectroscopic studies indicate that the di-gold complex fragments on dissolution in organic solvents. Approximate density-functional theory calculations find an electrostatic origin for the binding of two gold(I) centers to the unprotonated nitrogen atoms, despite greater orbital density on the porphyrin meso carbons. PMID:18780788

  18. Synthesis and characterization of functional thienyl-phosphine microporous polymers for carbon dioxide capture.

    PubMed

    Chen, Xianghui; Qiao, Shanlin; Du, Zhengkun; Zhou, Yuanhang; Yang, Renqiang

    2013-07-25

    A novel kind of functional organic microporous polymer is designed by introducing polar organic groups (P=O and P=S) and electron-rich heterocyclic into the framework to obtain high carbon dioxide capture capacity. The estimated Brunauer-Emmett-Teller (BET) surface areas of these polymers are about 600 m(2) g(-1) and the highest CO2 uptake is 2.26 mmol g(-1) (1.0 bar/273 K). Interestingly, the polymer containing P=O groups shows greater CO2 capture capacity than that containing P=S groups at the same temperature. In addition, these polymers show high isosteric heats of CO2 adsorption (28.6 kJ mol(-1) ), which can be competitive with some nitrogen-rich networks. Therefore, these microporous polymers are promising candidates for carbon dioxide capture.

  19. 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…

  20. (2-{[2-(diphenyl-phosphino)phen-yl]thio}-phen-yl)diphenyl-phosphine sulfide.

    PubMed

    Alvarez-Larena, Angel; Martinez-Cuevas, Francisco J; Flor, Teresa; Real, Juli

    2012-11-01

    In the title compound, C(36)H(28)P(2)S(2), the dihedral angle between the central benzene rings is 66.95 (13)°. In the crystal, molecules are linked via C(ar)-H⋯π and π-π inter-actions [shortest centroid-centroid distance between benzene rings = 3.897 (2) Å].

  1. cis-Bis(nitrato-κO,O')bis-(triethyl-phosphine oxide-κO)nickel(II).

    PubMed

    Seidel, Rüdiger W

    2009-05-07

    In the title compound, [Ni(NO(3))(2)(C(6)H(15)OP)(2)], the Ni(II) ion, lying on a crystallographic twofold axis, adopts a distorted octa-hedral coordination, consisting of O-donor atoms of two symmetry-related triethyl-phospine oxide and two bidentate nitrate ligands.

  2. Cyclic decapeptide gramicidin S derivatives containing phosphines: novel ligands for asymmetric catalysis.

    PubMed

    Guisado-Barrios, Gregorio; Muñoz, Bianca K; Kamer, Paul C J; Lastdrager, Bas; van der Marel, Gijs; Overhand, Mark; Vega-Vázquez, Marino; Martin-Pastor, Manuel

    2013-02-14

    The cyclic peptide gramicidin S was used as a rigid template to provide novel peptide-based bisphosphine ligands for transition metal catalysis. Two bisphosphine-coordinated Rh(I) complexes allowed asymmetric hydrogenation with 10-52% ee and the corresponding Pd(II) analogues catalysed asymmetric allylic alkylation with 13-15% ee.

  3. Syntheses and structural analyses of variable-stoichiometric Au-Pt-Ni carbonyl/phosphine clusters, Pt3(Pt(1-x)Ni(x))(AuPPh3)2(mu2-CO)4(CO)(PPh3)3 and Pt2(Pt(2-y)Ni(y))(AuPPh3)2(mu2-CO)4(CO)2(PPh3)2, with ligation-induced site-specific Pt/Ni substitutional disorder within butterfly-based Pt3(Pt(1-x)Ni(x))Au2 and Pt2(Pt(2-y)Ni(y))Au2 core-geometries.

    PubMed

    de Silva, Namal; Nichiporuk, Rita V; Dahl, Lawrence F

    2006-05-21

    In ongoing attempts of directed synthesis of high-nuclearity Au-Pt carbonyl/phosphine clusters with [Ni6(CO)12]2- used as reducing agent and CO source, we have isolated and characterized two new closely related variable-stoichiometric trimetallic clusters, Pt3(Pt(1-x)Ni(x))(AuPPh3)2(mu2-CO)4(CO)(PPh3)3 (1) and Pt2(Pt(2-y)Ni(y))(AuPPh3)2(mu2-CO)4(CO)2(PPh3)2 (2). Their M4Au2 cores may be envisioned as substitutional disordered butterfly-based M4Au2 frameworks (M = Pt/Ni) formed by connections of the two basal M(B) atoms with both (Au-Au)-linked Au(PPh3) moieties. Based upon low-temperature CCD X-ray diffraction studies of eight crystals obtained from different samples, ligation-induced site-specific Pt/Ni substitutional disorder (involving formal insertion of Ni in place of Pt) in a given crystal was found to occur only at the one OC-attached basal M(B) site in 1 or at both OC-attached basal M(B) sites in 2 corresponding to a crystal composite of the Pt3(Pt(1-x)Ni(x))Au2 core in 1 or of the Pt2(Pt(2-y)Ni(y))Au2 core in 2; the Ph3P-attached M(B) site (M(B) = Pt) in 1 and two wingtip M(w) sites (M(w) = Pt) in 1 and 2 were not substitutionally disordered. The resulting variable stoichiometry of the M4Au2 core in 1 may be viewed as a crystal composite of two superimposed individual stereoisomers, Pt4(AuPPh3)2(mu2-CO)4(CO)(PPh3)3 (1a) and Pt3Ni(AuPPh3)2(mu2-CO)4(CO)(PPh3)3 (1b), in the averaged unit cell of a given crystal. Likewise, 2 represents the crystal-averaged composite of three individual stereoisomers, Pt4(AuPPh3)2(mu2-CO)4(CO)2(PPh3)2 (2a), Pt3Ni(AuPPh3)2(mu2-CO)4(CO)2(PPh3)2 (2b), and Pt2Ni2(AuPPh3)2(mu2-CO)4(CO)2(PPh3)2 (2c). Formal Ni substitution for Pt at only the basal M(B) site(s) in the four crystal composites each of 1 and 2 was found to vary widely from 17% to 79% Ni in 1 and from 21% to 95% Ni in 2. Nevertheless, reasonably close Pt/Ni occupancy factors were found within each of the four pairs of composite crystals selected from samples obtained from

  4. Line positions and intensities of the phosphine (PH3) Pentad near 4.5μm

    SciTech Connect

    Malathy Devi, V.; Kleiner, Isabelle; Sams, Robert L.; Brown, Linda R.; Benner, D. Chris; 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. Finally, comparisons with other recent studies are discussed.

  5. cis-Bis(nitrato-κ2 O,O′)bis­(triethyl­phosphine oxide-κO)nickel(II)

    PubMed Central

    Seidel, Rüdiger W.

    2009-01-01

    In the title compound, [Ni(NO3)2(C6H15OP)2], the NiII ion, lying on a crystallographic twofold axis, adopts a distorted octa­hedral coordination, consisting of O-donor atoms of two symmetry-related triethyl­phospine oxide and two bidentate nitrate ligands. PMID:21582983

  6. Direct Synthesis of Silylamine from N2 and a Silane: Mediated by a Tridentate Phosphine Molybdenum Fragment.

    PubMed

    Liao, Qian; Cavaillé, Anthony; Saffon-Merceron, Nathalie; Mézailles, Nicolas

    2016-09-01

    A homogeneous system which is able to yield silylamine from N2 and bis(silane) in one pot is reported. Mechanistically a {(triphosphine)molybdenum(I)} fragment, generated in situ, splits N2 into the corresponding nitrido complex at room temperature. Then, functionalization of the molybdenum nitrido is achieved by double Si-H addition under mild reaction conditions. Moreover, the bis(silyl)amine product is decoordinated from the metal center. PMID:27491064

  7. 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.

  8. Characterizing traditional and chlorine-shared halogen bonds in complexes of phosphine derivatives with ClF and Cl2.

    PubMed

    Alkorta, Ibon; Elguero, José; Del Bene, Janet E

    2014-06-12

    Ab initio MP2/aug'-cc-pVTZ calculations have been carried out on the halogen-bonded complexes H2XP:ClF and H2XP:Cl2, with X = F, Cl, OH, NC, CN, CCH, CH3, and H. H2XP:ClF complexes are stabilized by chlorine-shared halogen bonds with short P-Cl and significantly elongated Cl-F distances. H2XP:Cl2 complexes with X = OH and CH3 form only chlorine-shared halogen bonds, while those with X = H, NC, and CN form only traditional halogen bonds. On the H2FP:Cl2, H2(CCH)P:Cl2, and H2ClP:Cl2 potential surfaces small barriers separate two equilibrium structures, one with a traditional halogen bond and the other with a chlorine-shared bond. The binding energies of H2XP:ClF and H2XP:Cl2 complexes are influenced by the electron-donating ability of H2XP and the electron accepting ability of ClF and ClCl, the nature of the halogen bond, other secondary interactions, and charge-transfer interactions. Changes in electron populations on P, F, and Cl upon complex formation do not correlate with changes in the chemical shieldings of these atoms. EOM-CCSD spin-spin coupling constants for complexes with chlorine-shared halogen bonds do not exhibit the usual dependencies on distance. (2X)J(P-F) and (2X)J(P-Cl) for complexes with chlorine-shared halogen bonds do not correlate with P-F and P-Cl distances, respectively. (1X)J(P-Cl) values for H2XP:ClF correlate best with the Cl-F distance, and approach the values of (1)J(P-Cl) for the corresponding cations H2XPCl(+). Values of (1X)J(P-Cl) for complexes H2XP:ClCl with chlorine-shared halogen bonds correlate with the binding energies of these complexes. (1)J(F-Cl) and (1)J(Cl-Cl) for complexes with chlorine-shared halogen bonds correlate linearly with the distance between P and the proximal Cl atom. In contrast, (2X)J(P-Cl) and (1X)J(P-Cl) for complexes with traditional halogen bonds exhibit more normal distance dependencies.

  9. Phosphine-free Stille-Migita chemistry for the mild and orthogonal modification of DNA and RNA.

    PubMed

    Krause, André; Hertl, Alexander; Muttach, Fabian; Jäschke, Andres

    2014-12-01

    An optimized catalyst system of [Pd2 (dba)3 ] and AsPh3 efficiently catalyzes the Stille reaction between a diverse set of functionalized stannanes and halogenated mono-, di- and oligonucleotides. The methodology allows for the facile conjugation of short and long nucleic acid molecules with moieties that are not compatible with conventional chemical or enzymatic synthesis, among them acid-, base-, or fluoride-labile protecting groups, fluorogenic and synthetically challenging moieties with good to near-quantitative yields. Notably, even azides can be directly introduced into oligonucleotides and (deoxy)nucleoside triphosphates, thereby giving direct access to "clickable" nucleic acids. PMID:25322724

  10. Coordination Chemistry Inside Polymeric Nanoreactors: Interparticle Metal Exchange and Ionic Compound Vectorization in Phosphine-Functionalized Amphiphilic Polymer Latexes.

    PubMed

    Chen, Si; Gayet, Florence; Manoury, Eric; Joumaa, Ahmad; Lansalot, Muriel; D'Agosto, Franck; Poli, Rinaldo

    2016-04-25

    Stable latexes of hierarchically organized core-cross-linked polymer micelles that are functionalized at the core with triphenylphosphine (TPP@CCM) have been investigated by NMR spectroscopic analysis at both natural (ca. pH 5) and strongly basic (pH 13.6) pH values after core swelling with toluene. The core-shell interface structuring forces part of the hydrophilic poly(ethylene oxide) (PEO) chains to reside inside the hydrophobic core at both pH values. Loading the particle cores with [Rh(acac)(CO)2 ] (acac=acetylacetonate) at various Rh/P ratios yielded polymer-supported [Rh(acac)(CO)(TPP)] (TPP=triphenylphosphine). The particle-to-particle rhodium migration is very fast at natural pH, but slows down dramatically at high pH, whereas the size distribution of the nanoreactors remains unchanged. The slow migration at pH 13.6 leads to the generation of polymer-anchored [Rh(OH)(CO)(TPP)2 ], which is also generated immediately upon the addition of NaOH to the particles with a [Rh(acac)(CO)] loading of 50 %. Similarly, treatment of the same particles with NaCl yielded polymer-anchored [RhCl(CO)(TPP)2 ]. Interparticle coupling occurs during these rapid processes. These experiments prove that the major contribution to metal migration is direct core-core contact. The slow migration at the high pH value, however, must result from a pathway that does not involve core-core contact. The facile penetration of the polymer cores by NaOH and NaCl results from the presence of shell-linked poly(ethylene oxide) methyl ether functions both outside and inside the polymer core-shell interface.

  11. Routes to ultra-pure alkyls of indium and gallium and their adducts with ethers, phosphines and amines

    NASA Astrophysics Data System (ADS)

    Jones, Anthony C.; Holliday, A. Kenneth; Cole-Hamilton, David J.; Ahmad, M. Munir; Gerrard, Neil D.

    1984-09-01

    Electrolysis of tetrahydrofuran (thf) solutions of dimethylmagnesium containing tetraethylammonium percholrate using a gallium anode gives [Me 3Ga·thf], but higher yields of both [Me 3Ga·thf] and [Me 3In·thf] are obtained on electrolysis of thf solutions of Grignard reagents with sacrificial metal anodes in the absence of a carrying electrolyte. The thf adducts can be converted into adducts with other Lewis bases, [ Me3M· L], M = Ga or In, L = PMe 3, PEt 3, NEt 3, by simple base exchange reactions. Base-free trimethylgallium can be prepared from: (i) reaction of methyl iodide with the intermetallic compound [Mg 5Ga 2] in a high boiling ether; (ii) electrolysis of Grignard reagents in high boiling ethers using sacrificial gallium anodes; (iii) reactions of GaCl 3 with Grignard reagents in high boiling ethers or (iv) ether exchange reaction between [Me 3Ga·OEt 2] and high boiling ethers. All of these reactions lead to adducts between trimethylgallium and the high boiling ether which, on heating, decompose to give base-free trimethylgallium. [Me 3Ga·OEt 2] can be prepared from reaction of Grignard reagents with gallium trichloride in diethylether or from electrolysis of Grignard reagents in diethyl ether using a sacrificial gallium anode. Similar reactions using an indium anode lead to [Me 3In·OEt 2] from which base-free trimethylindium can be liberated using known chemistry. The use of alkyls prepared in this way for vapour phase epitaxy as well as the purity of the alkyls are discussed.

  12. Line positions and intensities of the phosphine (PH3) Pentad near 4.5 μm

    NASA Astrophysics Data System (ADS)

    Malathy Devi, V.; Kleiner, Isabelle; Sams, Robert L.; Brown, Linda R.; Benner, D. Chris; 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. Coinage metal complexes with bridging hybrid phosphine-NHC ligands: synthesis of di- and tetra-nuclear complexes.

    PubMed

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

    2016-03-28

    A series of P-NHC-type hybrid ligands containing both PR2 and N-heterocyclic carbene (NHC) donors on meta-bis-substituted phenylene backbones, L(Cy), L(tBu) and L(Ph) (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 L(Ph)·n(HBr) (n = 1, 2) with Ag2O gave the pseudo-cubane [Ag4Br4(L(Ph))2], isostructural to [Ag4Br4(L(R))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(L(R))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(L(R))2] (R = Cy, tBu) dinuclear complexes were obtained from L(R)·HBr and [Cu5(Mes)5], Mes = 2,4,6-trimethylphenyl, which also feature bridging ligands and heteroleptic Cu centres. Although the various ligands L(R)l ed 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(L(tBu))2] to AuI by reaction with [AuCl(THT)] (THT = tetrahydrothiophene) led to L(tBu) transfer and to the dinuclear complex [Au2Cl2L(tBu)] with one L(tBu) ligand bridging the two Au centres. Except for the silver pseudo-cubanes, all other complexes do not exhibit metallophilic interactions. PMID:26886084

  14. Direct Synthesis of Silylamine from N2 and a Silane: Mediated by a Tridentate Phosphine Molybdenum Fragment.

    PubMed

    Liao, Qian; Cavaillé, Anthony; Saffon-Merceron, Nathalie; Mézailles, Nicolas

    2016-09-01

    A homogeneous system which is able to yield silylamine from N2 and bis(silane) in one pot is reported. Mechanistically a {(triphosphine)molybdenum(I)} fragment, generated in situ, splits N2 into the corresponding nitrido complex at room temperature. Then, functionalization of the molybdenum nitrido is achieved by double Si-H addition under mild reaction conditions. Moreover, the bis(silyl)amine product is decoordinated from the metal center.

  15. Phosphine-free Stille-Migita chemistry for the mild and orthogonal modification of DNA and RNA.

    PubMed

    Krause, André; Hertl, Alexander; Muttach, Fabian; Jäschke, Andres

    2014-12-01

    An optimized catalyst system of [Pd2 (dba)3 ] and AsPh3 efficiently catalyzes the Stille reaction between a diverse set of functionalized stannanes and halogenated mono-, di- and oligonucleotides. The methodology allows for the facile conjugation of short and long nucleic acid molecules with moieties that are not compatible with conventional chemical or enzymatic synthesis, among them acid-, base-, or fluoride-labile protecting groups, fluorogenic and synthetically challenging moieties with good to near-quantitative yields. Notably, even azides can be directly introduced into oligonucleotides and (deoxy)nucleoside triphosphates, thereby giving direct access to "clickable" nucleic acids.

  16. Coordination Chemistry Inside Polymeric Nanoreactors: Interparticle Metal Exchange and Ionic Compound Vectorization in Phosphine-Functionalized Amphiphilic Polymer Latexes.

    PubMed

    Chen, Si; Gayet, Florence; Manoury, Eric; Joumaa, Ahmad; Lansalot, Muriel; D'Agosto, Franck; Poli, Rinaldo

    2016-04-25

    Stable latexes of hierarchically organized core-cross-linked polymer micelles that are functionalized at the core with triphenylphosphine (TPP@CCM) have been investigated by NMR spectroscopic analysis at both natural (ca. pH 5) and strongly basic (pH 13.6) pH values after core swelling with toluene. The core-shell interface structuring forces part of the hydrophilic poly(ethylene oxide) (PEO) chains to reside inside the hydrophobic core at both pH values. Loading the particle cores with [Rh(acac)(CO)2 ] (acac=acetylacetonate) at various Rh/P ratios yielded polymer-supported [Rh(acac)(CO)(TPP)] (TPP=triphenylphosphine). The particle-to-particle rhodium migration is very fast at natural pH, but slows down dramatically at high pH, whereas the size distribution of the nanoreactors remains unchanged. The slow migration at pH 13.6 leads to the generation of polymer-anchored [Rh(OH)(CO)(TPP)2 ], which is also generated immediately upon the addition of NaOH to the particles with a [Rh(acac)(CO)] loading of 50 %. Similarly, treatment of the same particles with NaCl yielded polymer-anchored [RhCl(CO)(TPP)2 ]. Interparticle coupling occurs during these rapid processes. These experiments prove that the major contribution to metal migration is direct core-core contact. The slow migration at the high pH value, however, must result from a pathway that does not involve core-core contact. The facile penetration of the polymer cores by NaOH and NaCl results from the presence of shell-linked poly(ethylene oxide) methyl ether functions both outside and inside the polymer core-shell interface. PMID:27001452

  17. (2-{[2-(diphenyl­phosphino)phen­yl]thio}­phen­yl)diphenyl­phosphine sulfide

    PubMed Central

    Alvarez-Larena, Angel; Martinez-Cuevas, Francisco J.; Flor, Teresa; Real, Juli

    2012-01-01

    In the title compound, C36H28P2S2, the dihedral angle between the central benzene rings is 66.95 (13)°. In the crystal, molecules are linked via Car—H⋯π and π–π inter­actions [shortest centroid–centroid distance between benzene rings = 3.897 (2) Å]. PMID:23284423

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

    NASA Astrophysics Data System (ADS)

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

    2009-12-01

    We demonstrate high-efficiency turquoise-blue electrophosphorescence from bis[3,5-bis(2-pyridyl)-1,2,4-triazolato]platinum(II) [Pt(ptp)2] doped in 4-(diphenylphosphoryl)-N ,N-diphenylaniline(HM-A1). Organic light-emitting diodes (OLEDs) with 5% Pt(ptp)2:HM-A1 attain peak power efficiency of 61.2 lm/W, versus 40.8 lm/W for analogous devices employing the standard turquoise-blue phosphor bis[(4,6-difluorophenyl)-pyridinato-N,C2'](picolinato)iridium(III) (FIrpic). Devices with x% Pt(ptp)2:HM-A1 exhibit blue emission maxima (λmax˜480 nm) with monotonic increase in excimer/monomer intensity ratio at higher doping levels within 1%-10%, causing color shift toward green and less charge balance. This work represents a significant step toward optimizing future white OLEDs from the same phosphor via combination of low-doped and higher-doped or neat films.

  19. 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.

  20. Tri(1-adamantyl)phosphine: Expanding the Boundary of Electron-Releasing Character Available to Organophosphorus Compounds.

    PubMed

    Chen, Liye; Ren, Peng; Carrow, Brad P

    2016-05-25

    We report here the remarkable properties of PAd3, a crystalline air-stable solid accessible through a scalable SN1 reaction. Spectroscopic data reveal that PAd3, benefiting from the polarizability inherent to large hydrocarbyl groups, exhibits unexpected electron releasing character that exceeds other alkylphosphines and falls within a range dominated by N-heterocyclic carbenes. Dramatic effects in catalysis are also enabled by PAd3 during Suzuki-Miyaura cross-coupling of chloro(hetero)arenes (40 examples) at low Pd loading, including the late-stage functionalization of commercial drugs. Exceptional space-time yields are demonstrated for the syntheses of industrial precursors to valsartan and boscalid from chloroarenes with ∼2 × 10(4) turnovers in 10 min. PMID:27164163

  1. Bifunctional-Phosphine-Catalyzed Sequential Annulations of Allenoates and Ketimines: Construction of Functionalized Poly-heterocycle Rings.

    PubMed

    Li, Erqing; Jin, Hongxing; Jia, Penghao; Dong, Xuelin; Huang, You

    2016-09-12

    A highly stereoselective sequential annulation reaction between γ-substituted allenoates and ketimines was reported. By using bifunctional N-acyl aminophosphine catalysts, poly-heterocycle rings were obtained with high stereocontrol in good to excellent yields. The desired products have four contiguous stereogenic centers (one quaternary and three tertiary carbon centers), and only one isomer was obtained in all reactions. PMID:27529614

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

    DOEpatents

    Alexandratos, Spiro D.

    1987-01-01

    The specification discloses a method for the extraction of metal ions having a reduction potential of above about +0.3 from an aqueous solution. The method includes contacting the aqueous solution with a polymeric extractant having primary phosphinic acid groups, secondary phosphine oxide groups, or both phosphinic acid and phosphine oxide groups.

  3. 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.

  4. Titanocene-phosphine derivatives as precursors to cytotoxic heterometallic TiAu2 and TiM (M = Pd, Pt) compounds. Studies of their interactions with DNA.

    PubMed

    González-Pantoja, Jose F; Stern, Michael; Jarzecki, Andrzej A; Royo, Eva; Robles-Escajeda, Elisa; Varela-Ramírez, Armando; Aguilera, Renato J; Contel, María

    2011-11-01

    A series of tri- and bimetallic titanium-gold, titanium-palladium, and titanium-platinum derivatives of the general formulas [Ti{η(5)-C(5)H(4)(CH(2))(n)PPh(2)(AuCl)}(2)]·2THF [n = 0 (1); n = 2 (2); n = 3 (3)] and [TiCl(2){η(5)-C(5)H(4)κ-(CH(2))(n)PPh(2)}(2)(MCl(2))]·2THF [M = Pd, n = 0 (4); n = 2 (5); n = 3 (6) ; M = Pt, n = 0 (7); n = 2 (8); n = 3 (9)] have been synthesized and characterized by different spectroscopic techniques and mass spectrometry. The molecular structures of compounds 1-9 have been investigated by means of density functional theory calculations. The calculated IR spectra of the optimized structures fit well with the experimental IR data obtained for 1-9. The stability of the heterometallic compounds in deuterated solvents [CDCl(3), dimethyl sulfoxide (DMSO)-d(6), and mixtures 50:50 DMSO-d(6)/D(2)O and 1:99 DMSO-d(6)/D(2)O at acidic and neutral pH] has been evaluated by (31)P and (1)H NMR spectroscopy showing a higher stability for these compounds than for Cp(2)TiCl(2) or precursors [Ti{η(5)-C(5)H(4)(CH(2))(n)PPh(2)}(2)]. The new compounds display a lower acidity (1-2 units) than Cp(2)TiCl(2). The decomposition products have been identified over time. Complexes 1-9 have been tested as potential anticancer agents, and their cytotoxicity properties were evaluated in vitro against HeLa human cervical carcinoma and DU-145 human prostate cancer cells. TiAu(2) and TiPd compounds were highly cytotoxic for these two cell lines. The interactions of the compounds with calf thymus DNA have been evaluated by thermal denaturation (1-9) and by circular dichroism (1, 3, 4, and 7) spectroscopic methods. All of these complexes show a stronger interaction with DNA than that displayed by Cp(2)TiCl(2) at neutral pH. The data are consistent with electrostatic interactions with DNA for TiAu(2) compounds and for a covalent binding mode for TiM (M = Pd, Pt) complexes.

  5. 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)

  6. Scanning tunneling microscopy study of low temperature silicon epitaxy on hydrogen/silicon(001) and phosphine adsorption on silicon(111)-7x7

    NASA Astrophysics Data System (ADS)

    Ji, Jeong-Young

    A three-chamber ultra-high-vacuum (UHV) system with preparation, scanning tunneling microscopy (STM), and chemical vapor deposition (CVD) chambers was designed and built. Here, one can perform surface preparation, STM e-beam lithography, precursor gas dosing, ion sputtering, silicon epitaxy, and various measurements such as reflection high energy electron diffraction (RHEED), low energy electron diffraction (LEED), and Auger electron spectroscopy (AES). Processes performed in the ultra-clean preparation and gas-filled CVD chambers can be monitored by transferring the samples back to the STM chamber to take topographical images. Si deposition on H-terminated Si(001)-2x1 surfaces at temperatures 300--530 K was studied by scanning tunneling microscopy. Hydrogen apparently hinders Si adatom diffusion and enhances surface roughening. Post-growth annealing transfers the top layer atoms downward to fill in vacancies in the lower layer, restoring the crystallinity of the thin film. Hydrogen is shown to remain on the growth front up to at least 10 ML. Si deposition onto the H/Si(001)-3x1 surface at 530 K suggests that dihydride units further suppress Si adatom diffusion and increase surface roughness. PH3 adsorption on Si(111)-7x7 was studied for various exposures between 0.3--60 L at room temperature by means of the scanning-tunneling-microscopy (STM). PH3-, PH2-, H-reacted, and unreacted adatoms can be identified by analyzing STM images at different sample biases. Most of PH3 adsorbs dissociatively on the surface at initial exposure, generating H and PH2 adsorption sites, followed by molecular adsorption of PH3. Rest atoms are more reactive than the adatoms and PH 2-reacted rest atom sites are also observed in STM images. Statistical analysis shows that center adatoms are more reactive than corner adatoms and the saturation P coverage is ˜0.22 ML. Finally, 900 K annealing of a PH 3 dosed surface results in a disordered, partially P-covered surface and PH3 dosing at 900 K forms the same surface reconstruction as a P2-adsorbed surface at similar temperature.

  7. Studies toward an ideal fluorescence method to measure palladium in functionalized organic molecules: effects of sodium borohydride, temperature, phosphine ligand, and phosphate ions on kinetics.

    PubMed

    Song, Fengling; Carder, Evan J; Kohler, Clare C; Koide, Kazunori

    2010-12-01

    Residual metals in fine chemicals are currently detected by using inductively coupled plasma mass spectrometry, which requires expensive instrumentation and does not have high-throughput capabilities. Although fluorescent probes can be amenable to high-throughput analyses of metals, the utility of such analyses is limited due to the lack of generality. Herein, we report a significant improvement (≈19-fold) to our previously reported catalysis-based fluorescent probe for palladium. Specifically, we found that slightly elevated temperature dramatically improved the generality of the method and that the deallylation reaction of the nonfluorescent compound 1 was accelerated by phosphate ions in aqueous media. This method was capable of detecting 0.2 ppb palladium. We demonstrated reasonably accurate palladium detection in various active pharmaceutical ingredients and highly functionalized organic compounds. PMID:20938936

  8. 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

    2016-03-28

    Hybrid scorpionate ligand (OPPh2)2CHCH2C(O)Me (L) was synthesized and characterized by spectroscopic methods and X-ray diffraction. The selected coordination chemistry of L with UO2(NO3)2 and Ln(NO3)3 (Ln = La, Nd, Lu) has been evaluated. The isolated mono- and binuclear complexes, namely, [UO2(NO3)2L] (1), [{UO2(NO3)L}2(μ2-O2)]·EtOH (2), [La(NO3)3L2]·2.33MeCN (3), [Nd(NO3)3L2]·3MeCN (4), [Nd(NO3)2L2]+·(NO3)−·EtOH (5) and [Lu(NO3)3L2] (6) have been characterized by IR spectroscopy and elemental analysis. Single-crystal X-ray structures have been determined for complexes 1-5. Intramolecular intraligand π-stacking interactions between two phenyl fragments of the coordinated ligand(s) were observed in all complexes 1-5. 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 L 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 L extracts f-block elements (especially uranium) better than its unmodified prototype (OPPh2)2CH2.

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

    PubMed

    Thiery, Sébastien; Tondelier, Denis; Geffroy, Bernard; Jacques, Emmanuel; Robin, Malo; Métivier, Rémi; Jeannin, Olivier; Rault-Berthelot, Joëlle; Poriel, Cyril

    2015-10-01

    A new host material based on the 2,7,4'-substituted spirobifluorene platform has been designed and used in single-layer phosphorescent OLED with very high efficiency (EQE = 13.2%) and low turn-on voltage (2.4 V). This performance is among the best reported for green single-layer PhOLEDs and may open new avenues in the design of host materials for single-layer devices.

  10. Chemoselective nucleophilic arylation and single-step oxidative esterification of aldehydes using siloxanes and a palladium-phosphinous acid as a reaction switch.

    PubMed

    Lerebours, Rachel; Wolf, Christian

    2006-10-11

    Aldehydes and siloxanes form methyl esters in a single step through mild oxidative esterification in the presence of a palladium catalyst or, alternatively, afford secondary alcohols via TBAF-promoted arylation in the absence of a catalyst at increased temperatures under otherwise identical reaction conditions.

  11. 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 α-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 α-keto amides (TON = 4300) and in synthesis of alkynones (TON = 980).

  12. 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.

  13. 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 300 mg/kg of ALCAR by intraperitoneal injection. After 24 h, 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

  14. 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

  15. Alkane dehydrogenation catalyzed by rhodium(I) phosphine complexes. Observation of the stoichiometric alkane-to-rhodium hydrogen-transfer step

    SciTech Connect

    Shih, K.C.; Goldman, A.S. )

    1993-09-01

    RhL[sub 2]Cl (L = P[sup t]Pr[sub 3]) is found to dehydrogenate cyclooctane to give H[sub 2]RhL[sub 2]Cl and cyclooctene; this represents the first observation of the key hydrogen-transfer step proposed for related, catalytic alkane transfer-dehydrogenation systems. Using norbornene as a hydrogen acceptor, transfer-dehydrogenation is catalyzed but turnover numbers are low. 18 refs., 1 tab.

  16. A Significantly Twisted Spirocyclic Phosphine Oxide as a Universal Host for High-Efficiency Full-Color Thermally Activated Delayed Fluorescence Diodes.

    PubMed

    Li, Jing; Ding, Dongxue; Tao, Youtian; Wei, Ying; Chen, Runfeng; Xie, Linghai; Huang, Wei; Xu, Hui

    2016-04-01

    A universal thermally activated delayed fluorescence (TADF) host, 4'-diphenylphosphinoylspiro[fluorene-9,9'-xanthene] (SFXSPO), is constructed with a highly distorted and asymmetric configuration and disordered molecular packing in its solid state. SFXSPO successfully endows its full-color TADF diodes with state-of-the-art performance, e.g., the record external quantum efficiency of 22.5% and 19.1% and internal quantum efficiency of ≈100% for its yellow TADF diodes and single-host full-TADF nearly-white-emitting devices, respectively.

  17. 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

  18. Photooxidation of mixed aryl and biarylphosphines.

    PubMed

    Zhang, Dong; Celaje, Jeff A; Agua, Alon; Doan, Chad; Stewart, Timothy; Bau, Robert; Selke, Matthias

    2010-07-01

    Arylphosphines and dialkylbiarylphosphines react with singlet oxygen to form phosphine oxides and phosphinate esters. For mixed arylphosphines, the most electron-rich aryl group migrates to form the phosphinate, while for dialkylbiarylphosphines migration of the alkyl group occurs. Dialkylbiarylphosphines also yield arene epoxides, especially in electron-rich systems. Phosphinate ester formation is increased at high temperature, while protic solvents increase the yield of epoxide. The product distribution provides evidence for Buchwald's recent conformational model for the aerobic oxidation of dialkylbiarylphosphines.

  19. Advances in developing alternative treatments for postharvest pest control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    USDA-ARS made two significant advances in the last 10 years in the development of alternative treatments for postharvest pest control: oxygenated phosphine fumigation and nitric oxide fumigation. Oxygenated phosphine is phosphine fumigation in an oxygen enriched atmosphere. It is significantly more...

  20. Stabilization of 3:1 site-differentiated cubane-type clusters in the [Fe(4)S(4)](1+) core oxidation state by tertiary phosphine ligation: synthesis, core structural diversity, and S = 1/2 ground states.

    PubMed

    Deng, Liang; Majumdar, Amit; Lo, Wayne; Holm, R H

    2010-12-01

    An extensive series of 3:1 site-differentiated cubane-type clusters [Fe(4)S(4)(PPr(i)(3))(3)L] (L = Cl(-), Br(-), I(-), RO(-), RS(-), RSe(-)) has been prepared in 40-80% yield by two methods: ligand substitution of [Fe(4)S(4)(PPr(i)(3))(4)](1+) in tetrahydrofuran (THF)/acetonitrile by reaction with monoanions, and reductive cleavage of ligand substrates (RSSR, RSeSeR, I(2)) by the all-ferrous clusters [Fe(8)S(8)(PPr(i)(3))(6)]/[Fe(16)S(16)(PPr(i)(3))(8)] in THF. These neutral clusters are stable and do not undergo ligand redistribution reactions involving charged species in benzene and THF solutions. X-ray structural studies confirm the cubane stereochemistry but with substantial and variable distortions of the [Fe(4)S(4)](1+) core from idealized cubic core geometry. Based on Fe-S bond lengths, seven clusters were found to have compressed tetragonal distortions (4 short and 8 long bonds), and the remaining seven display other types of distortions with different combinations of long, short, and intermediate bond lengths. These results further emphasize the facile deformabililty of this core oxidation state previously observed in [Fe(4)S(4)(SR)(4)](3-) clusters. The Fe(2.25+) mean oxidation state was demonstrated from (57)Fe isomer shifts, and the appearance of two quadrupole doublets arises from the spin-coupled |9/2,4,1/2> state. The S = 1/2 ground state was further supported by electron paramagnetic resonance spectra and magnetic susceptibility data.

  1. Dual fluorescence from an isonido ReIII rhenacarborane phosphine complex, [7,10-mu-H-7-CO-7,7-(PPh3)2-isonido-7,8,9-ReC2B7H9].

    PubMed

    Buckner, Steven W; Fischer, Matthew J; Jelliss, Paul A; Luo, Rensheng; Minteer, Shelley D; Rath, Nigam P; Siemiarczuk, Aleksander

    2006-09-01

    The complex [7,10-mu-H-7-CO-7,7-(PPh3)2-isonido-7,8,9-ReC2B7H9] has been synthesized by treatment of the complex salt [NHMe3][3,3-Cl2-3,3-(CO)2-closo-3,1,2-ReC2B9H11] with PPh3 in refluxing THF (tetrahydrofuran) and isolated as intensely colored orange-red microcrystals. Spectroscopic NMR and IR data have suggested that the product has a highly asymmetric structure with two inequivalent PPh3 ligands and a single CO ligand. Measurement of 11B NMR spectra in particular have indicated seven distinct boron vertexes, although the resulting cage degradation by removal of two BH vertexes was confirmed only following X-ray crystallographic analysis, which revealed the pentadecahedral isonido-7,8,9-ReC2B7 architecture. The 11B NMR resonances span an enormous chemical shift range (Deltadelta = 113), and this appears to be a direct consequence of the deshielding of the boron vertex directly opposite the quadrilateral |ReCCB| aperture. The new complex has been shown by electrochemical measurements to undergo a reversible one-electron oxidation. Digitally simulated cyclic voltammograms support a proposed square scheme (E(1/2) = 0.58, 0.69 V vs ferrocene) involving a reversible isonido-closo transition of the metallacarborane cage. Most unusually for a metallacarborane complex, ambient temperature solutions in CH2Cl2 and DMF have been shown to be intensely turquoise-blue fluorescent (lambda(em) = 442 nm, Phi = 0.012). Fluorescence spectroscopy measurements in MeTHF (2-methyltetrahydrofuran) glass at 77 K have indicated that the likely cause of such a broad emission is dual fluorescence (lambda(em) = 404, 505 nm), with both emissions displaying vibronic structure. Following excited-state lifetime decay analysis, the emissive behavior has been accredited to metal-perturbed 1IL states, with the lower energy emission arising from a slight geometric distortion of the initially excited complex.

  2. 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.

  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. Six [Tp*WS3Cu2]-based clusters derived from [Et4N][Tp*WS3], Cu(I) salts and phosphine ligands: syntheses, structures and enhanced third-order NLO properties.

    PubMed

    Zhou, Li-Kuan; Liu, Quan; Zhao, Xin; Hu, Fei-Long; Liu, Shu-Chen; Ren, Zhi-Gang; Sun, Zhen-Rong; Lang, Jian-Ping

    2014-03-28

    Treatment of [Et4N][Tp*WS3] (Tp* = hydridotris(3,5-dimethylpyrazol-1-yl)borate) (1) with CuX (X = Br, SCN) and PPh3 or 1,1-bis(diphenylphosphino)methane (dppm) produced two neutral trinuclear clusters [Tp*W(μ3-S)(μ-S)2Cu2Br(PPh3)] (2) and [Tp*W(μ3-S)(μ-S)2Cu2(SCN)(dppm)]2·MeCN·Et2O (3·MeCN·Et2O). Reactions of 1 with [Cu(MeCN)4]PF6, NH4PF6 and 1,3-bis(diphenylphosphino)propane (dppp), N,N-bi(diphenylphosphanylmethyl)-2-aminopyridine (bdppmapy), N,N,N',N'-tetra(diphenylphosphanylmethyl)ethylenediamine (dppeda), or 1,4-N,N,N',N'-tetra(diphenylphosphanylmethyl)benzenediamine (dpppda) afforded four clusters containing butterfly-shaped [Tp*WS3Cu2] cores, [Tp*W(μ3-S)(μ-S)2Cu2(dpppds)](PF6)·1.25MeCN (dpppds = 1,3-bis(diphenylphosphino)propane disulfide) (4·1.25MeCN), [Tp*W(μ3-S)(μ-S)2Cu2(bdppmapy)](PF6)·3MeCN (5·3MeCN) and {[Tp*W(μ3-S)(μ-S)2Cu2]2(L)]}(PF6)2·Sol (6·Et2O: L = dppeda, Sol = Et2O; 7·1.25MeCN: L = dpppda, Sol = 1.25MeCN). Compounds 2-7 were characterized by elemental analysis, IR, UV-Vis, (1)H and (31)P{(1)H} NMR spectra, electrospray ion mass spectra (ESI-MS) and single-crystal X-ray diffraction. Compound 2 or 3 has a butterfly-shaped [Tp*WS3Cu2] core in which one [Tp*WS3] unit binds two Cu(I) centers via one μ3-S and two μ-S atoms. In the cationic structure of 4 or 5, one in situ-formed dpppds or bdppmapy combines with the [Tp*WS3Cu2] core via each of its two S atoms or two P atoms coordinated at each Cu(I) center. In the bicationic structure of 6 or 7, two [Tp*WS3Cu2] cores are linked by one dppeda or dpppda bridge to form a bicyclic structure. The isolation of 2-7 with unstable [Tp*WS3Cu2] cores may be ascribed to the coordination of P- or S-donor ligands at Cu(i) centers of these cores. The third-order nonlinear optical (NLO) properties of 2-7 in DMF were also investigated by using the femtosecond degenerate four-wave mixing (DFWM) technique at 800 nm.

  5. Glycine enhanced separation of Co(II) and Ni(II) with bis(2,4,4-trimethylpentyl)phosphinic acid (Cyanex 272) by liquid-liquid extraction and supported liquid membranes

    SciTech Connect

    Reichley-Yinger, L.; Danesi, P.R.

    1985-01-01

    The extraction behavior of Co and Ni ions from aqueous nitrate solution containing glycine, and their separation by liquid-liquid extraction and supported liquid membranes (SLMs) has been studied. The separation factor between the two metals is greatly enhanced by the presence of glycine. The enhancement is due to the preferential complexation of the Ni ions by glycine. The conditional equilibrium constants of the extraction reactions and the SLM permeability coefficients have been measured. The results indicate that metal glycinate complexes are not extracted and that in presence of glycine very clean Co-Ni separation can be obtained in a single SLM pass.

  6. Phosphine spectrum at 4-5 μm: Analysis and line-by-line simulation of 2ν2, ν2 + ν4, 2ν4, ν1, and ν3 bands

    NASA Astrophysics Data System (ADS)

    Tarrago, G.; Lacome, N.; Lévy, A.; Guelachvili, G.; Bézard, B.; Drossart, P.

    1992-07-01

    The five absorption bands of PH3 at 4-5 μm, i.e., 2ν2, ν2 + ν4, 2ν4, ν1, ν3, were simultaneously analyzed from FT spectra recorded with an apodized resolution of 0.0054 cm-1. A theoretical model suited to the strong vibro-rotational couplings among the five bands was used. More than 4400 transitions (J <= 16) pertaining to the five bands were assigned in the range 1885-2445 cm-1, but only 3766 relatively unblended transitions were finally retained for the adjustment of the upper state energy parameters. A set of 57 energy parameters was required to reproduce the experimental wavenumbers with an overall standard deviation of 0.009 cm-1, consistent with the estimated upper limit of uncertainty when taking into account all factors of experimental errors. Absolute intensities of about 1600 lines were also measured, mainly in 2ν2, ν2 + ν4, and 2ν4 bands. The fitting of these data was achieved by using a restricted set of 53 energy parameters which yields the best compromise for both spectral position and intensity analyses. An estimate was then obtained for the four dipole moment derivatives involved in 2ν2, ν2 + ν4, and 2ν4, allowing us to reproduce the intensity measurements with an overall standard deviation of 10.9%, consistent with the experimental uncertainties. Absolute bandstrengths relative to 2ν2, ν2 + ν4, and 2ν4 were thus derived for the first time. Last, a line-by-line simulation of the five bands (J <= 16) was carried out in a form suitable for planetary applications. PH3, which is observed in Jupiter and Saturn, is an important molecule for studies of their atmospheric structures. The 5-μm bands are of special importance because the atmospheres are sounded deep at these wavelengths. Laboratoire Associé aux Universités Paris-Sud et P. et M. Curie.

  7. Gene disruption technologies have the potential to transform stored product insect pest control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Stored product insects feed on grains and processed commodities manufactured from grain post-harvest, reducing the nutritional value and contaminating food. Currently, the main defense against stored product insect pests is the pesticide fumigant phosphine. Phosphine is highly toxic to all animals, ...

  8. Manganese(III) Acetate-Promoted Cross-Coupling Reaction of Benzothiazole/Thiazole Derivatives with Organophosphorus Compounds under Ball-Milling Conditions.

    PubMed

    Li, Liang; Wang, Jun-Jie; Wang, Guan-Wu

    2016-07-01

    The first solvent-free manganese(III) acetate-promoted reaction of benzothiazole/thiazole derivatives with organophosphorus compounds including phosphine oxides, phosphinate ester, and phosphonate diester has been efficiently developed under ball-milling conditions, providing a highly efficient and green protocol to structurally diverse C2-phosphonylated benzothiazole/thiazole derivatives with remarkable functional group tolerance and excellent yields. PMID:27248000

  9. 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.

  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. 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.…

  12. New (alpha-Hydroxyalkyl)phosphorus Amphiphiles: Synthesis and Dissociation Constants.

    PubMed

    Albouy, Dominique; Brun, Alice; Munoz, Aurelio; Etemad-Moghadam, Guita

    1998-10-16

    Direct synthesis of free (alpha-hydroxyalkyl)phosphinic acid amphiphiles 1 can be readily realized by sonication of the heterogeneous mixture of 50% aqueous hypophosphorous acid and long-chain aldehydes in the presence of catalytic amounts of hydrochloric acid. Oxidation of these phosphinic acids by DMSO in the presence of catalytic amounts of iodine quantitatively leads to the corresponding phosphonic acids 3. IR spectra of the phosphinic acids 1 in the condensed phase and in solution reveal the presence of intra- and intermolecular associations. Dissociation constants of the phosphorus acids 1 and 3 determined by potentiometric and (31)P NMR titrations show a good correlation between the two methods. The phosphinic acid amphiphiles 1 are slightly stronger than the corresponding phosphonic acids 3. (alpha-Hydroxyalkyl)phosphonium chlorides are prepared in good yields from the phosphine PH(3) and long-chain aldehydes in acidic media.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. End Group Functionalization of PFpP Macromolecules Via Fp Migration Insertion Reactions.

    PubMed

    Cao, Kai; Wang, Xiaosong

    2016-02-01

    PFpP macromolecules, synthesized via migration insertion polymerization of CpFe(CO)2 (CH2)3 PPh2 (FpP), exhibit reactive Fp end groups for further migration insertion reactions in the presence of phosphines. A number of alkyl diphenylphosphines with varied alkyl length, Ph2PCn (n = 6, 10, 18), have been prepared for the reaction, resulting in PFpP-PPh2Cn (n = 6, 10, 18) amphiphiles. The phosphines with longer alkyl chains impose steric hindrance for the reaction and therefore require longer reaction times and excess phosphines relative to PFpP.

  18. Synthesis of γ-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 γ-hydroxypropyl group which results from the ring opening and π-donor moieties such as aryl, allyl, propargyl and allene which originates from the Grignard reagent. PMID:26425187

  19. Synthesis and reactivity of fluoro complexes: Part 2. Rhodium(I) fluoro complexes with alkene and phosphine ligands. Synthesis of the first isolated rhodium(I) bifluoride complexes. Structure of [Rh3(mu3-OH)2(COD)(3)](HF2) by X-ray powder diffraction.

    PubMed

    Vicente, José; Gil-Rubio, Juan; Bautista, Delia; Sironi, Angelo; Masciocchi, Norberto

    2004-09-01

    The reaction between [Rh(mu-OH)(COD)](2) (COD = 1,5-cyclooctadiene) and 73% HF in THF gives [Rh(3)(mu(3)-OH)(2)(COD)(3)](HF(2)) (1). Its crystal structure, determined by ab initio X-ray powder diffraction methods (from conventional laboratory data), contains complex trimetallic cations linked together in 1D chains by a mu(3)-OH...F-H-F...HO-mu(3) sequence of strong hydrogen bonds. The complex [Rh(mu-F)(COE)(2)](2) (COE = cyclooctene; 2), prepared by reacting [Rh(mu-OH)(COE)(2)](2) with NEt(3).3HF (3:2), has been characterized. Complex 1 reacts with PR(3) (1:3) to give [RhF(COD)(PR(3))] [R = Ph (3), C(6)H(4)OMe-4 (4), (i)Pr (5), Cy (6)] that can be prepared directly by reacting [Rh(mu-OH)(COD)](2) with 73% HF and PR(3) (1:2:2). The reactions of 1 with PPh(3) or Et(3)P have been studied by NMR spectroscopy at different molar ratios. Complexes [RhF(PEt(3))(3)] (7), [RhF(COD)(PEt(3))] (8), and [RhF(PPh(3))(3)] (9) have been detected. The complex [Rh(F)(NBD)(iPr(3)P)] (NBD = norbornadiene; 10) was prepared by the sequential treatment of [Rh(mu-OMe)(NBD)](2) with 1 equiv of NEt(3).3HF and (i)Pr(3)P. The first isolated bifluoride rhodium(I) complexes [Rh(FHF)(COD)(PR(3))] [R = Ph (11), (i)Pr (12), Cy (13)], obtained by reacting fluoro complexes 3, 5, and 6 with NEt(3).3HF (3:1), have been characterized. The crystal structures of 3 and 11 have been determined.

  20. Charge donation to and dearomatization of benzene attending complexation: DFT estimates of binding energies of TpMXO(L) with benzene, for Tp = hydridotris(pyrazolyl) borate, MXO = MoNO, ReCO, and WNO, and L = ammonia, N-methylimidazole, pyridine, phosphine, methyl isocyanide, and carbon monoxide.

    PubMed

    Harman, W Dean; Trindle, Carl

    2005-01-30

    By density functional methods we characterize the bonding and charge distribution in complexes of benzene with dearomatizing agents tpReCO(L), tpMoNO(L), and tpWNO(L), where tp = hydrido Tris (pyrazolyl)borate), for a range of ligands L. Our LSDA and B3LYP density functional calculations use the Spartan LACVP+ basis and pseudopotential on Re, Mo, and W and 6-31G* on light atoms. The binding energy is strongly dependent on the nature of the ligand L, being greatest for L = ammonia and N-methylimidazole and weakest for CH3NC and CO. We find a correlation between strength of binding and electron transfer from the dearomatizing agents toward benzene. For the most strongly bound systems we find substantial (up to 500 millielectrons) charge transfer towards benzene, while for the most weakly bound systems charge is withdrawn from benzene. Structural details illustrate the ability of Re, Mo, and W species to dearomatize complexed benzene, which is extensive for all but the most weakly bound species with L = MeNC and CO. Re and W dearomatizing agents, which are computed and observed to form stable complexes with benzene, may be economic alternatives to osmium dearomatizing agents. PMID:15593348

  1. Chemoselective ligation

    DOEpatents

    Saxon, Eliana; Bertozzi, Carolyn R.

    2011-04-12

    The present invention features a chemoselective ligation reaction that can be carried out under physiological conditions. In general, the invention involves condensation of a specifically engineered phosphine, which can provide for formation of an amide bond between the two reactive partners resulting in a final product comprising a phosphine moiety, or which can be engineered to comprise a cleavable linker so that a substituent of the phosphine is transferred to the azide, releasing an oxidized phosphine byproduct and producing a native amide bond in the final product. The selectivity of the reaction and its compatibility with aqueous environments provides for its application in vivo (e.g., on the cell surface or intracellularly) and in vitro (e.g., synthesis of peptides and other polymers, production of modified (e.g., labeled) amino acids).

  2. Chemoselective ligation

    DOEpatents

    Saxon, Eliana; Bertozzi, Carolyn Ruth

    2011-12-13

    The present invention features a chemoselective ligation reaction that can be carried out under physiological conditions. In general, the invention involves condensation of a specifically engineered phosphine, which can provide for formation of an amide bond between the two reactive partners resulting in a final product comprising a phosphine moiety, or which can be engineered to comprise a cleavable linker so that a substituent of the phosphine is transferred to the azide, releasing an oxidized phosphine byproduct and producing a native amide bond in the final product. The selectivity of the reaction and its compatibility with aqueous environments provides for its application in vivo (e.g., on the cell surface or intracellularly) and in vitro (e.g., synthesis of peptides and other polymers, production of modified (e.g., labeled) amino acids).

  3. Chemoselective ligation

    DOEpatents

    Saxon, Eliana; Bertozzi, Carolyn Ruth

    2010-11-23

    The present invention features a chemoselective ligation reaction that can be carried out under physiological conditions. In general, the invention involves condensation of a specifically engineered phosphine, which can provide for formation of an amide bond between the two reactive partners resulting in a final product comprising a phosphine moiety, or which can be engineered to comprise a cleavable linker so that a substituent of the phosphine is transferred to the azide, releasing an oxidized phosphine byproduct and producing a native amide bond in the final product. The selectivity of the reaction and its compatibility with aqueous environments provides for its application in vivo (e.g., on the cell surface or intracellularly) and in vitro (e.g., synthesis of peptides and other polymers, production of modified (e.g., labeled) amino acids).

  4. Chemoselective ligation

    DOEpatents

    Saxon, Eliana; Bertozzi, Carolyn

    2003-05-27

    The present invention features a chemoselective ligation reaction that can be carried out under physiological conditions. In general, the invention involves condensation of a specifically engineered phosphine, which can provide for formation of an amide bond between the two reactive partners resulting in a final product comprising a phosphine moiety, or which can be engineered to comprise a cleavable linker so that a substituent of the phosphine is transferred to the azide, releasing an oxidized phosphine byproduct and producing a native amide bond in the final product. The selectivity of the reaction and its compatibility with aqueous environments provides for its application in vivo (e.g., on the cell surface or intracellularly) and in vitro (e.g., synthesis of peptides and other polymers, production of modified (e.g., labeled) amino acids).

  5. Chemoselective ligation

    DOEpatents

    Saxon, Eliana; Bertozzi, Carolyn R.

    2011-05-10

    The present invention features a chemoselective ligation reaction that can be carried out under physiological conditions. In general, the invention involves condensation of a specifically engineered phosphine, which can provide for formation of an amide bond between the two reactive partners resulting in a final product comprising a phosphine moiety, or which can be engineered to comprise a cleavable linker so that a substituent of the phosphine is transferred to the azide, releasing an oxidized phosphine byproduct and producing a native amide bond in the final product. The selectivity of the reaction and its compatibility with aqueous environments provides for its application in vivo (e.g., on the cell surface or intracellularly) and in vitro (e.g., synthesis of peptides and other polymers, production of modified (e.g., labeled) amino acids).

  6. Chemoselective ligation

    DOEpatents

    Saxon, Eliana; Bertozzi, Carolyn R.

    2010-02-23

    The present invention features a chemoselective ligation reaction that can be carried out under physiological conditions. In general, the invention involves condensation of a specifically engineered phosphine, which can provide for formation of an amide bond between the two reactive partners resulting in a final product comprising a phosphine moiety, or which can be engineered to comprise a cleavable linker so that a substituent of the phosphine is transferred to the azide, releasing an oxidized phosphine byproduct and producing a native amide bond in the final product. The selectivity of the reaction and its compatibility with aqueous environments provides for its application in vivo (e.g. on the cell surface or intracellularly) and in vitro (e.g., synthesis of peptides and other polymers, production of modified (e.g., labeled) amino acids).

  7. Re and 99mTc complexes of BodP3 – multi-modality imaging probes†

    PubMed Central

    Davies, Laura H.; Kasten, Benjamin B.; Arrowsmith, Rory L.; Ge, Haobo; Botchway, Stan W.; Clegg, William; Harrington, Ross W.

    2015-01-01

    A fluorescent tridentate phosphine, BodP3 (2), forms rhenium complexes which effectively image cancer cells. Related technetium analogues are also readily prepared and have potential as dual SPECT/fluorescent biological probes. PMID:25248386

  8. 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.

  9. 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).

  10. 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.

  11. 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.

  12. Chemical Emergencies Overview

    MedlinePlus

    ... Methyl bromide Methyl isocyanate Nicotine Nitrogen mustard Opioids Organic solvents Osmium tetroxide Paraquat Phosgene Phosgene oxime Phosphine ... by preventing the nervous system from working properly Organic solvents —agents that damage the tissues of living ...

  13. A convenient and selective palladium-catalyzed aerobic oxidation of alcohols.

    PubMed

    Gowrisankar, Saravanan; Neumann, Helfried; Gördes, Dirk; Thurow, Kerstin; Jiao, Haijun; Beller, Matthias

    2013-11-18

    An efficient procedure for the oxidation of primary and secondary alcohols to aldehydes and ketones, respectively, with molecular oxygen under ambient conditions has been achieved. By applying catalytic amounts of Pd(OAc)2 in the presence of tertiary phosphine oxides (O=PR3) as ligands, a variety of substrates are selectively oxidized without formation of ester byproducts. Spectroscopic investigations and DFT calculations suggest stabilization of the active palladium(II) catalyst by phosphine oxide ligands.

  14. Methods for suppressing isomerization of olefin metathesis products

    SciTech Connect

    Firth, Bruce E.; Kirk, Sharon E.; Gavaskar, Vasudeo S.

    2015-09-22

    A method for suppressing isomerization of an olefin metathesis product produced in a metathesis reaction includes adding an isomerization suppression agent to a mixture that includes the olefin metathesis product and residual metathesis catalyst from the metathesis reaction under conditions that are sufficient to passivate at least a portion of the residual metathesis catalyst. The isomerization suppression agent is phosphorous acid, a phosphorous acid ester, phosphinic acid, a phosphinic acid ester or combinations thereof. Methods of refining natural oils are described.

  15. Homolytic substitution at phosphorus for C–P bond formation in organic synthesis

    PubMed Central

    2013-01-01

    Summary Organophosphorus compounds are important in organic chemistry. This review article covers emerging, powerful synthetic approaches to organophosphorus compounds by homolytic substitution at phosphorus with a carbon-centered radical. Phosphination reagents include diphosphines, chalcogenophosphines and stannylphosphines, which bear a weak P–heteroatom bond for homolysis. This article deals with two transformations, radical phosphination by addition across unsaturated C–C bonds and substitution of organic halides. PMID:23843922

  16. SOLVENT EXTRACTION PROCESS FOR URANIUM FROM CHLORIDE SOLUTIONS

    DOEpatents

    Blake, C.A. Jr.; Brown, K.B.; Horner, D.E.

    1960-05-24

    An improvement was made in a uranium extraction process wherein the organic extractant is a phosphine oxide. An aqueous solution containing phosphate ions or sulfate ions together with uranium is provided with a source of chloride ions during the extraction step. The presence of the chloride ions enables a phosphine oxide to extract uranium in the presence of strong uranium- complexing ions such as phosphate or sulfate ions.

  17. 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

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

    SciTech Connect

    Ramprasad, Dorai; Waller, Francis Joseph

    1999-01-01

    This invention relates to a process for producing acetic anhydride by the reaction of methyl acetate, carbon monoxide, and hydrogen at elevated temperatures and pressures in the presence of an alkyl halide and a heterogeneous, bifunctional catalyst that contains an insoluble polymer having pendant quaternized phosphine groups, some of which phosphine groups are ionically bonded to anionic Group VIII metal complexes, the remainder of the phosphine groups being bonded to iodide. In contrast to prior art processes, no accelerator (promoter) is necessary to achieve the catalytic reaction and the products are easily separated from the catalyst by filtration. The catalyst can be recycled for consecutive runs without loss in activity. Bifunctional catalysts for use in carbonylating dimethyl ether are also provided.

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

    SciTech Connect

    Ramprasad, D.; Waller, F.J.

    1999-04-06

    This invention relates to a process for producing acetic anhydride by the reaction of methyl acetate, carbon monoxide, and hydrogen at elevated temperatures and pressures in the presence of an alkyl halide and a heterogeneous, bifunctional catalyst that contains an insoluble polymer having pendant quaternized phosphine groups, some of which phosphine groups are ionically bonded to anionic Group VIII metal complexes, the remainder of the phosphine groups being bonded to iodide. In contrast to prior art processes, no accelerator (promoter) is necessary to achieve the catalytic reaction and the products are easily separated from the catalyst by filtration. The catalyst can be recycled for consecutive runs without loss in activity. Bifunctional catalysts for use in carbonylating dimethyl ether are also provided.

  20. 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.

  1. Discovery of potent and selective inhibitors of human aminopeptidases ERAP1 and ERAP2 by screening libraries of phosphorus-containing amino acid and dipeptide analogues.

    PubMed

    Węglarz-Tomczak, Ewelina; Vassiliou, Stamatia; Mucha, Artur

    2016-08-15

    A collection of fifty phosphonic and phosphinic acids was screened for inhibition of ERAP1 and ERAP2, the human endoplasmic reticulum aminopeptidases. The cooperative action of these enzymes is manifested by trimming a variety of antigenic precursors to be presented on the cell surface by major histocompatibility class I. The SAR studies revealed several potent compounds, particularly among the phosphinic dipeptide analogues, that were strong inhibitors of ERAP2 (Ki=100-350nM). A wide structural diversity of the applied organophosphorus compounds, predominantly non-proteinogenic analogues, allowed identification of representatives selective toward only one form of ERAP. For example, N'-substituted α,β-diaminophosphonates and phosphinates exhibited potency only toward ERAP2, which is in agreement with the P1 basic substrate-oriented specificity. Such discriminating ligands are invaluable tools for elucidating the precise role of a particular aminopeptidase in the concerted function of antigen processing and in human diseases. PMID:27390066

  2. Basic Reactivity Pattern of a Cyclic Disilylated Germylene

    PubMed Central

    2016-01-01

    In order to estimate the reactivity of disilylated germylene phosphine adducts, a cyclic version of this compound class was reacted with a number of different reagents. Reactions with the chalcogens sulfur, selenium, and tellurium led to dimers of the heavy ketone analogues. Reactions with water and ethyl bromide proceeded to give the respective oxidized germanol and germyl bromide. Two different reactions with alkynes were observed which led either to a germacyclopropene, by addition of tolane to the germylene, or to a silagermacyclobutene, likely formed by addition of the alkyne across a silagermene. Reaction via the silagermene was also observed in the reaction with benzophenone. Reaction of a germylene phosphine adduct with GeCl2·(dioxane) provided insertion of the silylated germylene into a Ge–Cl bond, leading to a germylated chlorogermylene phosphine adduct. PMID:27570360

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

    DOEpatents

    Wai, Chien M.; Smart, Neil G.; Phelps, Cindy

    2001-01-01

    A method for separating a desired metal or metalloi from impurities using a supercritical extraction process based on solubility differences between the components, as well as the ability to vary the solvent power of the supercritical fluid, is described. The use of adduct-forming agents, such as phosphorous-containing ligands, to separate metal or metalloid chelates in such processes is further disclosed. In preferred embodiments, the extraction solvent is supercritical carbon dioxide and the chelating agent is selected from the group consisting of .beta.-diketones; phosphine oxides, such as trialkylphosphine oxides, triarylphosphine oxides and alkylarylphosphine oxides; phosphinic acids; carboxylic acids; phosphates, such as trialkylphosphates, triarylphosphates and alkylarylphosphates; crown ethers; dithiocarbamates; phosphine sulfides; phosphorothioic acids; thiophosphinic acids; halogenated analogs of these chelating agents; and mixtures of these chelating agents. In especially preferred embodiments, at least one of the chelating agents is fluorinated.

  4. [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 α-alkylation and β'-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 α-amino-H-phosphinate with alkenyl triflate, followed by diastereoselective hydrogenation of the alkene moiety. PMID:25174361

  5. 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.

  6. Statistical Analysis of Near-Infrared Spectra of Saturn and Rings Pre-Cassini

    NASA Astrophysics Data System (ADS)

    Jezewski, Sean

    2007-10-01

    Medium resolution near-infrared spectra of Saturn were acquired at NASA/InfraRed Telescope Facility (IRTF) with Spex prior to the arrival of Cassini at Saturn. The data were acquired in a cross-dispersed mode, with a slit of 15 x 0.5 arc sec, with a resolution comparable to Cassini/VIMS data. Phosphine is a species of interest, as it is only present when dredged from the deep atmosphere. The temporal variation of the global distribution of various chemical species, such as phosphine, is mapped by utilizing an IDL-based suite of tools designed for post-processing of the extracted spectra. These tools were developed for the analysis of the recent Jovian North Temperate Belt (NTBs) disturbance (Yanamandra-Fisher et al., DPS 2007). The pre-Cassini spectra of Saturn provide a valuable window to trace the distribution of phosphine in the southern hemisphere and its subsequent global distribution. This analysis will map the temporal evolution of various species, especially phosphine, as function of latitude and longitude from 2001 to 2004. Initial results indicate variability of phosphine increasing from the southern pole towards the equator and increasing in time towards southern solstice in late 2002/early 2003. A principle component analysis (PCA), will be performed on the spatial maps to illustrate any underlying spatial relations between the various species and physical models. The results of this study will extend the results of Cassini/VIMS, to understand the seasonal variations of phosphine. This research was performed by SWJ at the Jet Propulsion Laboratory under the auspices of an USRP summer internship.

  7. Quasi-two-dimensional metallic hydrogen inside di-phosphide at high pressure

    NASA Astrophysics Data System (ADS)

    Degtyarenko, N. N.; Mazur, E. A.

    2016-09-01

    The method of mathematical modelling was used for the calculation of the structural, electronic, phononic, and other characteristics of various normal phases of phosphorus hydrides with stoichiometry PHk. It was shown that the di-phosphine may form 2D lattice of the metallic hydrogen in it, stabilized by phosphorus atoms under high hydrostatic pressure. The resulting structure with the elements of H-P-H has a locally stable (or metastable) phonon spectrum. The properties of di-phosphine were compared with the properties of similar structures such as the sulphur hydrides.

  8. Partial pressures and nature of products. Application to the photolysis of PH3 and NH3 in the atmosphere of Jupiter and Saturn.

    PubMed

    Guillemin, J C; El Chaouch, S; Bouayad, A; Janati, T

    2001-01-01

    The photolysis of mixtures of gases containing NH3 or PH3 presents important differences mainly due to the strength of the X-H bond. On some examples, these differences are evidenced and the consequences for mixtures of gases containing these two compounds are shown: the photolysis of ammonia and ethylene mainly gives ethyl-, butyl- and hexylamine whereas the photolysis of phosphine and ethylene leads to ethyl- and vinylphosphine. When gaseous mixtures of NH3, PH3 and ethylene are photolyzed together, the presence of phosphine dramatically decreases the formation of nitrogen derivatives. The relevance of such lab studies to the atmospheres of Jupiter and Saturn is discussed.

  9. Phosphorus-containing imide resins

    NASA Technical Reports Server (NTRS)

    Varma, I. K.; Fohlen, G. M.; Parker, J. A. (Inventor)

    1985-01-01

    Cured polymers of bis and tris-imides derived from tris(m-aminophenyl) phosphine oxides by reaction with maleic anhydride or its derivatives, and addition polymers of such imides, including a variant in which a monoimide is condensed with a dianhydride and the product is treated with a further quantity of maleic anhydride prior to curing are disclosed and claimed. Such polymers are flame resistant. Also disclosed are an improved method of producing tris(m-aminophenyl) phosphine oxides from the nitro analogues by reduction with hydrazine hydrate using palladized charcoal or Raney nickel as the catalyst and fiber reinforced cured resin composites.

  10. Phosphorus-containing imide resins

    NASA Technical Reports Server (NTRS)

    Varma, I. K.; Fohlen, G. M.; Parker, J. A. (Inventor)

    1983-01-01

    Bis- and tris-imides derived from tris (m-aminophenyl) phosphine oxides by reaction with maleic anhydride or its derivatives, and addition polymers of such imides, including a variant in which a mono-imide is condensed with a dianhydride and the product is treated with a further quantity of maleic anhydride. Such monomers or their oligomes may be used to impregnate fibers and fabrics which when cured, are flame resistant. Also an improved method of producing tris (m-aminophenyl) phosphine oxides from the nitro analogues by reduction with hydrazine hydrate using palladized charcoal or Raney nickel as the catalyst is described.

  11. Synthesis of Chiral β-Amino Nitroalkanes via Rhodium-Catalyzed Asymmetric Hydrogenation.

    PubMed

    Li, Pan; Zhou, Ming; Zhao, Qingyang; Wu, Weilong; Hu, Xinquan; Dong, Xiu-Qin; Zhang, Xumu

    2016-01-01

    The asymmetric hydrogenation of β-amino nitroolefins has been successfully achieved by rhodium/bis(phosphine)-thiourea L1 with excellent enantioselectivities and yields (up to 96% ee, 96% yield, >99% conversion, TON up to 1000) under mild conditions. Chiral β-amino nitroalkane products and their derivatives are versatile intermediates in organic synthesis. PMID:26652759

  12. Asymmetric Hydrogenation of Azaindoles: Chemo- and Enantioselective Reduction of Fused Aromatic Ring Systems Consisting of Two Heteroarenes.

    PubMed

    Makida, Yusuke; Saita, Masahiro; Kuramoto, Takahiro; Ishizuka, Kentaro; Kuwano, Ryoichi

    2016-09-19

    High enantioselectivity was achieved for the hydrogenation of azaindoles by using the chiral catalyst, which was prepared from [Ru(η(3) -methallyl)2 (cod)] and a trans-chelating bis(phosphine) ligand (PhTRAP). The dearomative reaction exclusively occurred on the five-membered ring, thus giving the corresponding azaindolines with up to 97:3 enantiomer ratio. PMID:27561154

  13. TBAI-catalyzed oxidative C-H functionalization: a new route to benzo[b]phosphole oxides.

    PubMed

    Zhang, Yun; Hu, Gaobo; Ma, Dumei; Xu, Pengxiang; Gao, Yuxing; Zhao, Yufen

    2016-02-14

    The first metal-free, efficient TBAI-catalyzed radical addition/cyclization of diaryl(arylethynyl)phosphine oxides with toluene derivatives has been developed, affording a general, one-step approach to structurally sophisticated benzo[b]phosphole oxides via sequential C-H functionalization along with the formation of two new C-C bonds.

  14. Asymmetric hydrogenation of aromatic ketones by new recyclable ionic tagged ferrocene-ruthenium catalyst system.

    PubMed

    Xu, Di; Zhou, Zhi-Ming; Dai, Li; Tang, Li-Wei; Zhang, Jun

    2015-05-01

    Newly developed ferrocene-oxazoline-phosphine ligands containing quaternary ammonium ionic groups exhibited excellent catalytic performance for the ruthenium-catalyzed hydrogenation of aromatic ketonic substrates to give chiral secondary alcohols with high levels of conversions and enantioselectivities. Simple manipulation process, water tolerance, high activity and good recyclable property make this catalysis practical and appealing.

  15. Catalytic Asymmetric Synthesis of anti-α,β-Diamino Acid Derivatives.

    PubMed

    Izumi, Sanae; Kobayashi, Yusuke; Takemoto, Yoshiji

    2016-02-19

    A novel approach to chiral anti-α,β-diamino acid derivatives through tandem orthogonal organocatalysis has been developed. Chiral phosphoric acid catalysts control the chemo-, regio-, and stereoselective addition of hydroxylamines to alkylideneoxazolones, while a phosphine catalyst promotes the isomerization of Z- alkylideneoxazolones to the more reactive E- alkylideneoxazolones.

  16. Multiphosphine-Oxide Hosts for Ultralow-Voltage-Driven True-Blue Thermally Activated Delayed Fluorescence Diodes with External Quantum Efficiency beyond 20.

    PubMed

    Zhang, Jing; Ding, Dongxue; Wei, Ying; Han, Fuquan; Xu, Hui; Huang, Wei

    2016-01-20

    Highly efficient low-voltage-driven -true-blue thermally activated -delayed fluorescence diodes are realized through employing a tri-phosphine oxide host (2,2',4-tris(di(phenyl) -phosphoryl)-diphenylether (DPETPO)) with a record external quantum efficiency of 23.0% and the lowest onset voltage of 2.8 V to date.

  17. Merging Gold and Organocatalysis: A Facile Asymmetric Synthesis of Annulated Pyrroles

    PubMed Central

    Hack, Daniel; Loh, Charles C J; Hartmann, Jan M; Raabe, Gerhard; Enders, Dieter

    2014-01-01

    The combination of cinchona-alkaloid-derived primary amine and AuI–phosphine catalysts allowed the selective C—H functionalization of two adjacent carbon atoms of pyrroles under mild reaction conditions. This sequential dual activation provides seven-membered-ring-annulated pyrrole derivatives in excellent yields and enantioselectivities. PMID:24590817

  18. Rhenium and technetium bi- and tricarbonyl complexes in a new strategy for biomolecule incorporation using click chemistry.

    PubMed

    Hayes, Thomas R; Kasten, Benjamin B; Barnes, Charles L; Benny, Paul D

    2014-05-21

    A versatile strategy to prepare fac-[M(I)(CO)3](+) and cis-[M(I)(CO)2](+) (M = Re, (99m)Tc) complexes was developed using Huisgen click chemistry and monodentate phosphine ligands to readily incorporate biomolecules and tailor the chemical properties.

  19. Dehydrogenation processes via C-H activation within alkylphosphines.

    PubMed

    Grellier, Mary; Sabo-Etienne, Sylviane

    2012-01-01

    Phosphines are commonly used in organometallic chemistry and are present in a wide variety of catalytic systems. This feature article highlights the advances made in dehydrogenation processes occurring within alkylphosphines, with the aim of further developing catalytic processes involving C-H activation together with potential applications in the field of hydrogen storage. PMID:21956347

  20. Palladium-catalyzed synthesis of dibenzophosphole oxides via intramolecular dehydrogenative cyclization.

    PubMed

    Kuninobu, Yoichiro; Yoshida, Takuya; Takai, Kazuhiko

    2011-09-16

    Dibenzophosphole oxides were obtained from secondary hydrophosphine oxides with a biphenyl group by dehydrogenation via phosphine-hydrogen and carbon-hydrogen bond cleavage in the presence of a catalytic amount of palladium(II) acetate, Pd(OAc)(2). By using this reaction, a ladder-type dibenzophosphole oxide could also be synthesized by double intramolecular dehydrogenative cyclization. PMID:21819045

  1. Aluminum hypophosphite microencapsulated to improve its safety and application to flame retardant polyamide 6.

    PubMed

    Ge, Hua; Tang, Gang; Hu, Wei-Zhao; Wang, Bi-Bo; Pan, Ying; Song, Lei; Hu, Yuan

    2015-08-30

    Aluminum hypophosphite (AHP) is an effective phosphorus-containing flame retardant. But AHP also has fire risk that it will decompose and release phosphine which is spontaneously flammable in air and even can form explosive mixtures with air in extreme cases. In this paper, AHP has been microencapsulated by melamine cyanurate (MCA) to prepare microencapsulated aluminum hypophosphite (MCAHP) with the aim of enhancing the fire safety in the procedure of production, storage and use. Meanwhile, MCA was a nitrogen-containing flame retardant that can work with AHP via the nitrogen-phosphorus synergistic effect to show improved flame-retardant property than other capsule materials. After microencapsulation, MCA presented as a protection layer inhibit the degradation of AHP and postpone the generation of phosphine. Furthermore, the phosphine concentration could be effectively diluted by inert decomposition products of MCA. These nonflammable decomposition products of MCA could separate phosphine from air delay the oxidizing reaction with oxygen and decrease the heat release rate, which imply that the fire safety of AHP has been improved. Furthermore, MCAHP was added into polyamide 6 to prepare flame retardant polyamide 6 composites (FR-PA6) which show good flame retardancy.

  2. Aluminum hypophosphite microencapsulated to improve its safety and application to flame retardant polyamide 6.

    PubMed

    Ge, Hua; Tang, Gang; Hu, Wei-Zhao; Wang, Bi-Bo; Pan, Ying; Song, Lei; Hu, Yuan

    2015-08-30

    Aluminum hypophosphite (AHP) is an effective phosphorus-containing flame retardant. But AHP also has fire risk that it will decompose and release phosphine which is spontaneously flammable in air and even can form explosive mixtures with air in extreme cases. In this paper, AHP has been microencapsulated by melamine cyanurate (MCA) to prepare microencapsulated aluminum hypophosphite (MCAHP) with the aim of enhancing the fire safety in the procedure of production, storage and use. Meanwhile, MCA was a nitrogen-containing flame retardant that can work with AHP via the nitrogen-phosphorus synergistic effect to show improved flame-retardant property than other capsule materials. After microencapsulation, MCA presented as a protection layer inhibit the degradation of AHP and postpone the generation of phosphine. Furthermore, the phosphine concentration could be effectively diluted by inert decomposition products of MCA. These nonflammable decomposition products of MCA could separate phosphine from air delay the oxidizing reaction with oxygen and decrease the heat release rate, which imply that the fire safety of AHP has been improved. Furthermore, MCAHP was added into polyamide 6 to prepare flame retardant polyamide 6 composites (FR-PA6) which show good flame retardancy. PMID:25867591

  3. Mild access to planar-chiral ortho-condensed aromatic ferrocenes via gold(i)-catalyzed cycloisomerization of ortho-alkynylaryl ferrocenes.

    PubMed

    Urbano, Antonio; Hernández-Torres, Gloria; Del Hoyo, Ana M; Martínez-Carrión, Alicia; Carmen Carreño, M

    2016-05-11

    An efficient approach to (Rp) planar-chiral tri- and tetracyclic ortho-condensed aromatic ferrocenes was developed through the enantioselective cationic Au(i)-catalyzed cycloisomerization, in the presence of bidentate phosphine ligand (R)-DTBM-Segphos, from readily available ortho-alkynylaryl ferrocenes under very mild conditions (11 examples, up to 92% yield and 93% ee).

  4. Synthesis and Migratory-Insertion Reactivity of CpMo(CO)[subscript3](CH[subscript3]): Small-Scale Organometallic Preparations Utilizing Modern Glovebox Techniques

    ERIC Educational Resources Information Center

    Whited, Matthew T.; Hofmeister, Gretchen E.

    2014-01-01

    Experiments are described for the reliable small-scale glovebox preparation of CpMo(CO)[subscript 3](CH[subscript 3]) and acetyl derivatives thereof through phosphine-induced migratory insertion. The robust syntheses introduce students to a variety of organometallic reaction mechanisms and glovebox techniques, and they are easily carried out…

  5. 40 CFR 721.10370 - Phosphonic acid, p-octyl-, lanthanum (3+) salt (2:1).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Phosphonic acid, p-octyl-, lanthanum... New Uses for Specific Chemical Substances § 721.10370 Phosphonic acid, p-octyl-, lanthanum (3+) salt... substance identified as phosphinic acid, p-octyl-, lanthanum (3+) salt (2:1) (PMN P-10-99; CAS No....

  6. 40 CFR 721.10370 - Phosphonic acid, p-octyl-, lanthanum (3+) salt (2:1).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Phosphonic acid, p-octyl-, lanthanum... New Uses for Specific Chemical Substances § 721.10370 Phosphonic acid, p-octyl-, lanthanum (3+) salt... substance identified as phosphinic acid, p-octyl-, lanthanum (3+) salt (2:1) (PMN P-10-99; CAS No....

  7. 40 CFR 721.10370 - Phosphonic acid, p-octyl-, lanthanum (3+) salt (2:1).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Phosphonic acid, p-octyl-, lanthanum... New Uses for Specific Chemical Substances § 721.10370 Phosphonic acid, p-octyl-, lanthanum (3+) salt... substance identified as phosphinic acid, p-octyl-, lanthanum (3+) salt (2:1) (PMN P-10-99; CAS No....

  8. Synthesis of 2H-Azirines by Iridium-Catalyzed Decarboxylative Ring Contraction of Isoxazol-5(4H)-ones.

    PubMed

    Okamoto, Kazuhiro; Shimbayashi, Takuya; Yoshida, Masato; Nanya, Atsushi; Ohe, Kouichi

    2016-06-13

    A phosphine-free iridium-catalyzed reaction of isoxazol-5(4H)-ones (isoxazolones) has been developed, and affords 2H-azirines through decarboxylation and ring contraction. This method provides an efficient and environmentally benign protocol which could replace the conventional approaches used to synthesize 2H-azirines. PMID:27125870

  9. Catalytic enantio- and diastereoselective Mannich reaction of α-substituted isocyanoacetates and ketimines.

    PubMed

    de la Campa, Raquel; Gammack Yamagata, Adam D; Ortín, Irene; Franchino, Allegra; Thompson, Amber L; Odell, Barbara; Dixon, Darren J

    2016-08-23

    The highly diastereo- and enantioselective Mannich addition/cyclisation reaction of α-substituted isocyanoacetate ester pronucleophiles and (hetero)aryl and alkyl methyl ketone-derived ketimines using a silver acetate and a cinchona-derived amino phosphine binary catalyst system is reported. PMID:27500289

  10. Visible light electroluminescent diodes of indium-gallium phosphide

    NASA Technical Reports Server (NTRS)

    Clough, R.; Richman, D.; Tietjen, J.

    1970-01-01

    Vapor deposition and acceptor impurity diffusion techniques are used to prepare indium-gallium phosphide junctions. Certain problems in preparation are overcome by altering gas flow conditions and by increasing the concentration of phosphine in the gas. A general formula is given for the alloy's composition.

  11. Development of a Lewis Base Catalyzed Selenocyclization Reaction

    ERIC Educational Resources Information Center

    Collins, William

    2009-01-01

    The concept of Lewis base activation of selenium Lewis acids has been effectively reduced to practice in the Lewis base catalyzed selenofunctionalization of unactivated olefins. In this reaction, the weakly acidic species, "N"-phenylselenyl succinimide, is cooperatively activated by the addition of a "soft" Lewis base donor (phosphine sulfides,…

  12. The 1982 NASA/ASEE summer faculty fellowship research program, abstracts of research projects, 1st and 2nd-year fellows

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Phosphine photolysis in Jupiter's atmosphere is discussed in relation to organic chemical evolution. Workload in AFTI F-16 test flights, infrared observations of M17, and the relation between rock and vegetation types are presented. Orbiter transfer vehicle aerothermodynamics simulation problems are also discussed.

  13. Merging gold and organocatalysis: a facile asymmetric synthesis of annulated pyrroles.

    PubMed

    Hack, Daniel; Loh, Charles C J; Hartmann, Jan M; Raabe, Gerhard; Enders, Dieter

    2014-04-01

    The combination of cinchona-alkaloid-derived primary amine and Au(I) -phosphine catalysts allowed the selective C-H functionalization of two adjacent carbon atoms of pyrroles under mild reaction conditions. This sequential dual activation provides seven-membered-ring-annulated pyrrole derivatives in excellent yields and enantioselectivities.

  14. Synthesis of 2H-Azirines by Iridium-Catalyzed Decarboxylative Ring Contraction of Isoxazol-5(4H)-ones.

    PubMed

    Okamoto, Kazuhiro; Shimbayashi, Takuya; Yoshida, Masato; Nanya, Atsushi; Ohe, Kouichi

    2016-06-13

    A phosphine-free iridium-catalyzed reaction of isoxazol-5(4H)-ones (isoxazolones) has been developed, and affords 2H-azirines through decarboxylation and ring contraction. This method provides an efficient and environmentally benign protocol which could replace the conventional approaches used to synthesize 2H-azirines.

  15. Plasma deposition of amorphous metal alloys

    DOEpatents

    Hays, A.K.

    1979-07-18

    Amorphous metal alloy coatings are plasma-deposited by dissociation of vapors of organometallic compounds and metalloid hydrides in the presence of a reducing gas, using a glow discharge. Tetracarbonylnickel, phosphine, and hydrogen constitute a typical reaction mixture of the invention, yielding a NiPC alloy.

  16. Multiheteromacrocycles that Complex Metal Ions. Fourth Progress Report, 1 May 1977 -- 30 April 1978

    DOE R&D Accomplishments Database

    Cram, D. J.

    1978-01-15

    Results are reported in a program to design, synthesize, and evaluate polycyclic host organic compounds for their abilities to complex and lipophilize guest metal ions. Work during the reporting period was devoted to synthesis and study of cyclohexametaphenylenes and cyclic phosphine oxides. (JRD)

  17. Construction and probing of multisite chiral catalysts: dendrimer fixation of c2-symmetrical diphosphinerhodium complexes.

    PubMed

    Engel, Gerald D; Gade, Lutz H

    2002-09-16

    A series of chiral phosphine-functionalized poly(propyleneimine) (PPI) dendrimers was synthesized by the reaction of carboxyl-linked C(2)-chiral pyrphos ligand (pyrphos=3,4-bis(diphenylphosphino)pyrrolidine) with zeroth-fourth generation PPI using ethyl-N,N-dimethylaminopropylcarbodiimide (EDC)/1-hydroxybenzotriazol as a coupling reagent. The dendrimers obtained were characterized by NMR spectroscopy and elemental analysis as well as FAB and MALDI-TOF mass spectrometry, which established their molecular masses of up to 20 700 amu. Metalation of the multi-site phosphines with [Rh(COD)(2)]BF(4) cleanly yielded the cationic rhododendrimers containing up to 32 metal centers (for the fourth generation species), representing the largest chiral phosphine dendrimer catalyst studied to date. The complete metalation of the chiral phosphine sites was demonstrated by (31)P NMR spectroscopy and the observation of the coordination-shifted AB part of the ABX spin system (delta(A)=33.9, delta(B)=32.9; (1)J(Rh,P)=150, 153 Hz; (2)J(P,P)=28 Hz). The relationship between the size/generation of the dendrimer and its catalytic properties was established in the asymmetric hydrogenation of Z-methyl-alpha-acetamidocinammate and dimethyl itaconate. A decrease in both activity and selectivity of the dendrimer catalysts was observed on going to the higher generations. PMID:12298024

  18. Monomeric and dimeric disulfide complexes of nickel(II).

    PubMed

    Iluc, Vlad M; Laskowski, Carl A; Brozek, Carl K; Harrold, Nicole D; Hillhouse, Gregory L

    2010-08-01

    Elemental sulfur reacts with a bulky bis(phosphine)nickel(0) complex to give a monomeric nickel(II) eta(2)-disulfido complex, oxidation of which results in the elimination of sulfur with dimerization to give an eta(2),eta(2)-disulfidodinickel(II) derivative in which the S-S bond can be reductively cleaved in a redox-reversible fashion. PMID:20586478

  19. Total synthesis of aeruginosin 98B.

    PubMed

    Trost, Barry M; Kaneko, Toshiyuki; Andersen, Neil G; Tappertzhofen, Christoph; Fahr, Bruce

    2012-11-21

    The first total synthesis of aeruginosin 98B was accomplished. The key step is a highly diastereoselective Pd-catalyzed intramolecular asymmetric allylic alkylation reaction of a diastereomeric mixture of allylic carbonates that is enabled by the use of racemic phosphine ligand L1.

  20. Nickel-catalyzed transfer hydrogenation of ketones using ethanol as a solvent and a hydrogen donor.

    PubMed

    Castellanos-Blanco, Nahury; Arévalo, Alma; García, Juventino J

    2016-09-14

    We report a nickel(0)-catalyzed direct transfer hydrogenation (TH) of a variety of alkyl-aryl, diaryl, and aliphatic ketones with ethanol. This protocol implies a reaction in which a primary alcohol serves as a hydrogen atom source and solvent in a one-pot reaction without any added base. The catalytic activity of the nickel complex [(dcype)Ni(COD)] (e) (dcype: 1,2-bis(dicyclohexyl-phosphine)ethane, COD: 1,5-cyclooctadiene), towards transfer hydrogenation (TH) of carbonyl compounds using ethanol as the hydrogen donor was assessed using a broad scope of ketones, giving excellent results (up to 99% yield) compared to other homogeneous phosphine-nickel catalysts. Control experiments and a mercury poisoning experiment support a homogeneous catalytic system; the yield of the secondary alcohols formed in the TH reaction was monitored by gas chromatography (GC) and NMR spectroscopy. PMID:27511528

  1. Synthetic and Thermodynamic Investigations of Ancillary Ligand Influence on Catalytic Organometallic Systems. Final Report

    SciTech Connect

    Nolan, Steven

    2003-03-20

    During the grant period we have been involved in synthesizing and experimentally determining solution enthalpy values associated with partially fluorinated ligands. This has lead to the publication of manuscripts dealing with synthetic, calorimetric and catalytic behavior of partially fluorinated ligands. The collaboration with Los Alamos researchers has lead to the publication of catalytic results in sc CO{sub 2} which have proven very interesting. Furthermore, we have also examined ligands that behave as phosphine mimics. The N-heterocyclic carbenes have been explored as alternatives for tertiary phosphines and have resulted in the design and construction of efficient palladium and nickel system capable of performing C-C and C-N cross coupling reactions. The initial studies in this areas were made possible by exploratory work conducted under the DOE/EPSCoR grant.

  2. Isolable gold(I) complexes having one low-coordinating ligand as catalysts for the selective hydration of substituted alkynes at room temperature without acidic promoters.

    PubMed

    Leyva, Antonio; Corma, Avelino

    2009-03-01

    Hydration of a wide range of alkynes to the corresponding ketones has been afforded in high yields at room temperature by using gold(I)-phosphine complexes as catalyst, with no acidic cocatalysts required. Suitable substrates covering alkyl and aryl terminal alkynes, enynes, internal alkynes, and propargylic alcohols, including enantiopure forms, are cleanly transformed to the corresponding ketones in nearly quantitative yields. Acid-labile groups present in the substrates are preserved. The catalytic activity strongly depends on both the nature of the phosphine coordinated to the gold (I) center and the softness of the counteranion, the complex AuSPhosNTf(2) showing the better activity. A plausible mechanism for the hydration of alkynes through ketal intermediates is proposed on the basis of kinetic studies. The described catalytic system should provide an efficient alternative to mercury-based methodologies and be useful in synthetic programs.

  3. Sudden infant death syndrome: a possible primary cause.

    PubMed

    Richardson, B A

    1994-01-01

    The hypothesis that poisoning by phosphines, arsines and stibines might be the primary cause of sudden infant death syndrome (SIDS) was investigated. Most mattress materials contain phosphorus or antimony compounds as fire retardant additives. Mattress materials in areas affected by the warmth and perspiration of the sleeping infant were found to be naturally infected by the fungus Scopulariopsis brevicaulis which is thought to be capable of generating phosphines, arsines and stibines from materials containing phosphorus, arsenic or antimony compounds. These gases may cause anticholinesterase poisoning and cardiac failure in infants, but contributory factors include the prone sleeping position and overwrapping. In England and Wales, the progressive increase in SIDS between 1951 and 1988 seems to be related to increasing use of phosphorus and antimony compounds as fire retardents in cot mattresses.

  4. Bis(pentamethylcyclopentadienyl)ytterbium: An investigation of weak interactions in solution using multinuclear NMR spectroscopy

    SciTech Connect

    Schwartz, D.J.

    1995-07-01

    NMR spectroscopy is ideal for studying weak interactions (formation enthalpy {le}20 kcal/mol) in solution. The metallocene bis(pentamethylcyclopentadienyl)ytterbium, Cp*{sub 2}Yb, is ideal for this purpose. cis-P{sub 2}PtH{sub 2}complexes (P = phosphine) were used to produce slow-exchange Cp*{sub 2}YbL adducts for NMR study. Reversible formation of (P{sub 2}PtH){sub 2} complexes from cis-P{sub 2}PtH{sub 2} complexes were also studied, followed by interactions of Cp*{sub 2}Yb with phosphines, R{sub 3}PX complexes. A NMR study was done on the interactions of Cp*{sub 2}Yb with H{sub 2}, CH{sub 4}, Xe, CO, silanes, stannanes, C{sub 6}H{sub 6}, and toluene.

  5. Synthesis and Reactivity Studies of α,α-Difluoromethylphosphinates

    PubMed Central

    Abrunhosa-Thomas, Isabelle; Coudray, Laëtitia

    2010-01-01

    The preparation and reactivity of some α,α-difluorophosphinates is investigated. Alkylation of H-phosphinates with LiHMDS and ClCF2H gives the corresponding α,α-difluorophosphinates in good yield. Deprotonation of these reagents with alkyllithium or LDA is then studied. Subtle electronic effects translate into significant differences in the deprotonation/alkylation of the two “Ciba-Geigy reagents” (EtO)2CRP(O)(OEt)H (R = H, Me). On the other hand, attempted methylation of difluoromethyl-octyl-phosphinic acid butyl ester resulted in the exclusive alkylation of the octyl chain. Finally, reaction with carbonyl compounds results in the formation of 1,1-difluoro-2-phosphinoyl compounds. PMID:20725593

  6. Carbons and hydrogen by persistent metal radicals. Final report, April 1, 1993--October 31, 1994

    SciTech Connect

    Not Available

    1995-12-31

    The synthesis of complexed rhenium radicals is demonstrated from the reaction of sterically demanding phosphine with the triphenylmethyl complex [n{sup 5}-CPh{sub 3}]Re(CO){sub 3}. Low yields are experienced unless high concentrations of phosphine ligands are employed with the mechanism of this reaction yet unknown. A complexed rhenium dimer is also synthesized, but in low yield. X-ray crystallography reveals that the sixth coordination site of the electron deficient rhenium cation (an extremely strong Lewis acid) is occupied by an agostic interaction with one of the pendant C-H bonds of the cyclohexyl ring of the complex. Preliminary results show that the rhenium complexes have a significantly different chemistry from similar tungsten analogs in reactivity and isotope exchange rates. It is hypothesized that the rhenium complexes would be useful in catalyzing the isotope exchange between water and hydrogen.

  7. A General Approach To Fabricate Fe3O4 Nanoparticles Decorated with Pd, Au, and Rh: Magnetically Recoverable and Reusable Catalysts for Suzuki C-C Cross-Coupling Reactions, Hydrogenation, and Sequential Reactions.

    PubMed

    Gonzàlez de Rivera, Ferran; Angurell, Inmaculada; Rossell, Marta D; Erni, Rolf; Llorca, Jordi; Divins, Núria J; Muller, Guillermo; Seco, Miquel; Rossell, Oriol

    2013-09-01

    A facile strategy has been explored for loading noble metals onto the surface of ferrite nanoparticles with the assistance of phosphine-functionalized linkers. Palladium loading is shown to occur with participation of both the phosphine function and the surface hydroxyl groups. Hybrid nanoparticles containing simultaneously Pd and Au (or Rh) are obtained by successive loading of metals. Similarly, ferrite nanoparticles decorated with Pd, Au, and Rh have also been formed by using the same strategy. The catalytic properties of the new nanoparticles are evidenced in processes such as reduction of 4-nitrophenol or hydrogenation of styrene. Besides, the sequential process involving a cross-coupling reaction followed by reduction of 1-nitrobiphenyl has been successfully achieved by employing Pd/Au decorated nanoferrite particles.

  8. Remarkably diastereoselective synthesis of a chiral biphenyl diphosphine ligand and its application in asymmetric hydrogenation

    PubMed Central

    Qiu, Liqin; Wu, Jing; Chan, Shusun; Au-Yeung, Terry T.-L.; Ji, Jian-Xin; Guo, Rongwei; Pai, Cheng-Chao; Zhou, Zhongyuan; Li, Xingshu; Fan, Qing-Hua; Chan, Albert S. C.

    2004-01-01

    Essentially complete atropdiastereoselectivity was realized in the preparation of biaryl diphosphine dioxide by asymmetric intramolecular Ullmann coupling and oxidative coupling with central-to-axial chirality transfer. A bridged C2-symmetric biphenyl phosphine ligand possessing additional chiral centers on the linking unit of the biphenyl groups was synthesized. No resolution step was required for the preparation of the enantiomerically pure chiral ligand. These findings offer a general and practical tool for the development of previously uninvestigated atropdiastereomeric biaryl phosphine ligands. The diphosphine ligand was found to be highly effective in the asymmetric hydrogenation of α- and β-ketoesters, 2-(6′-methoxy-2′-naphthyl)propenoic acid, β-(acylamino)acrylates, and enol acetates. PMID:15067137

  9. Synergistic Extraction of Copper from Nitrate Solutions Using β-Hydroxy-Naphthaldoxime and Organophosphorus Compounds into Carbon-Tetrachloride

    NASA Astrophysics Data System (ADS)

    Dey, Pulak; Basu, Sukalyan

    2011-12-01

    The extraction behavior of Cu(II) from an aqueous nitrate medium employing β-hydroxy-naphthaldoxime in carbon tetrachloride has been investigated in the presence of several organophosphorus donors like tri-octyl phosphine oxide, tri-butyl phosphine oxide, and tri-butyl phosphate at pH 1.5. The concentration of the metal was measured by atomic absorption spectrophotometry. Synergism was observed when neutral donor was added because of the formation of the adduct [Cu(L)2.(S)] in CCl4 (S denotes neutral donor). The equilibrium constants of the binary system using β-hydroxy-naphthaldoxime and the ternary system involving another addition of an organophosphorus compound were calculated from the extraction date obtained. Furthermore, the temperature dependence of the equilibrium constants was also investigated to evaluate standard enthalpy (Δ H°), entropy (Δ S°), and free energy (Δ G°) of the reactions proposed.

  10. Migration insertion polymerization (MIP) of cyclopentadienyldicarbonyldiphenylphosphinopropyliron (FpP): a new concept for main chain metal-containing polymers (MCPs).

    PubMed

    Wang, Xiaosong; Cao, Kai; Liu, Yibo; Tsang, Brian; Liew, Sean

    2013-03-01

    We report a conceptually new polymerization technique termed migration insertion polymerization (MIP) for main chain metal-containing polymer (MCP) synthesis. Cyclopentadienyldicarbonyldiphenylphosphinopropyliron (FpP) is synthesized and polymerized via MIP, resulting in air stable poly(cyclopentadienylcarbonyldiphenylphosphinobutanoyliron) (PFpP) displaying narrow molecular weight distribution. The backbone of PFpP contains asymmetric iron units connected by both phosphine coordination and Fe-acyl bonds, which is representative of a new type of polymer. Furthermore, PFpP is tested to be soluble in a wide range of organic solvents and shown to possess reactive Fp end groups. PFpP amphiphiles have therefore been prepared via an end group migration insertion reaction in the presence of oligoethylene phosphine. PMID:23425192

  11. Controlling charge transport in blue organic light-emitting devices by chemical functionalization of host materials

    SciTech Connect

    Polikarpov, Evgueni; Koech, Phillip K.; Wang, Liang; Swensen, James S.; Cosimbescu, Lelia; Rainbolt, James E.; Von Ruden, Amber L.; Gaspar, Daniel J.; Padmaperuma, Asanga B.

    2011-01-18

    Generation of white light from OLEDs for general lighting applications requires a highly efficient blue component. However, a stable and power efficient blue OLED component with simple device architecture remains a significant challenge partly due to lack of appropriate host materials. Here we report the photophysical and device properties of ambipolar host phosphine oxide based materials. In this work, we studied the effect of the structural modification made to phosphine oxide-based hosts on the charge balance. We observed significant changes in charge transport within the host occurred upon small modifications to their chemical structure. As a result, an alteration of the chemical design of these materials allows for the control of charge balance of the OLED.

  12. Asymmetric cyanation of imines via dipeptide-derived organophosphine dual-reagent catalysis

    PubMed Central

    Wang, Hong-Yu; Zheng, Chang-Wu; Chai, Zhuo; Zhang, Jia-Xing; Zhao, Gang

    2016-01-01

    Over the past few decades, enantioselective phosphine organocatalysis has evolved rapidly into a highly efficient catalytic strategy for a range of useful reactions. However, as restricted by the traditional catalytic modes, some important reactions, such as asymmetric Strecker-type reactions, have thus far been out of reach of this strategy. Reported herein is an application of enantioselective phosphine organocatalysis for asymmetric Strecker-type reactions, enabled by a dual-reagent catalyst system in which the key organophosphorus zwitterion intermediate, generated in situ by mixing a chiral dipeptide-derived multifunctional organophosphine with methyl acrylate, is used as a highly efficient chiral Lewis base catalyst. The high efficiency of this catalytic system is demonstrated in the asymmetric cyanation of isatin-derived ketimines and azomethine aldimines as well as in the kinetic resolution of racemic 3-substituted azomethines. Mechanistic studies provide experimental evidence for the intermediacy of the putative zwitterion and its role as a catalytically active Lewis base. PMID:27625043

  13. Feasibility of actinide separation from UREX-like raffinates using a combination of sulfur- and oxygen-donor extractants

    SciTech Connect

    Zalupski, P.R.; Peterman, D.R.; Riddle, C.L.

    2013-07-01

    A synergistic combination of bis(o-trifluoromethylphenyl)dithios-phosphinic acid and trioctylphosphine oxide has been recently shown to selectively remove uranium, neptunium, plutonium and americium from aqueous environment containing up to 0.5 M nitric acid and 5.5 g/l fission products. Here the feasibility of performing this complete actinide recovery from aqueous mixtures is forecasted for a new organic formulation containing sulfur donor extractant of modified structure based on Am(III) and Eu(III) extraction data. A mixture of bis(bis-m,m-trifluoromethyl)phenyl)-dithios-phosphinic acid and TOPO in toluene enhances the extraction performance, accomplishing Am/Eu differentiation in aqueous mixtures up to 1 M nitric acid. The new organic recipe is also less susceptible to oxidative damage resulting from radiolysis. (authors)

  14. Staudinger ligation as a method for bioconjugation.

    PubMed

    van Berkel, Sander S; van Eldijk, Mark B; van Hest, Jan C M

    2011-09-12

    In 1919 the German chemist Hermann Staudinger was the first to describe the reaction between an azide and a phosphine. It was not until recently, however, that Bertozzi and co-workers recognized the potential of this reaction as a method for bioconjugation and transformed it into the so-called Staudinger ligation. The bio-orthogonal character of both the azide and the phosphine functions has resulted in the Staudinger ligation finding numerous applications in various complex biological systems. For example, the Staudinger ligation has been utilized to label glycans, lipids, DNA, and proteins. Moreover, the Staudinger ligation has been used as a synthetic method to construct glycopeptides, microarrays, and functional biopolymers. In the emerging field of bio-orthogonal ligation strategies, the Staudinger ligation has set a high standard to which most of the new techniques are often compared. This Review summarizes recent developments and new applications of the Staudinger ligation.

  15. A comprehensive study of olefin metathesis catalyzed by Ru-based catalysts.

    PubMed

    Poater, Albert; Cavallo, Luigi

    2015-01-01

    During a Ru-catalyzed reaction of an olefin with an alkylidene moiety that leads to a metallacycle intermediate, the cis insertion of the olefin can occur from two different directions, namely side and bottom with respect to the phosphine or N-heterocyclic ligand (NHC), depending on the first or second generation Grubbs catalyst. Here, DFT calculations unravel to which extent the bottom coordination of olefins with respect is favored over the side coordination through screening a wide range of catalysts, including first and second generation Grubbs catalysts as well as the subsequent Hoveyda derivatives. The equilibrium between bottom and side coordination is influenced by sterics, electronics, and polarity of the solvent. The side attack is favored for sterically less demanding NHC and/or alkylidene ligands. Moreover the generation of a 14-electron species is also discussed, with either pyridine or phosphine ligands to dissociate.

  16. Extracting metals directly from metal oxides

    DOEpatents

    Wai, Chien M.; Smart, Neil G.; Phelps, Cindy

    1997-01-01

    A method of extracting metals directly from metal oxides by exposing the oxide to a supercritical fluid solvent containing a chelating agent is described. Preferably, the metal is an actinide or a lanthanide. More preferably, the metal is uranium, thorium or plutonium. The chelating agent forms chelates that are soluble in the supercritical fluid, thereby allowing direct removal of the metal from the metal oxide. In preferred embodiments, the extraction solvent is supercritical carbon dioxide and the chelating agent is selected from the group consisting of .beta.-diketones, halogenated .beta.-diketones, phosphinic acids, halogenated phosphinic acids, carboxylic acids, halogenated carboxylic acids, and mixtures thereof. In especially preferred embodiments, at least one of the chelating agents is fluorinated. The method provides an environmentally benign process for removing metals from metal oxides without using acids or biologically harmful solvents. The chelate and supercritical fluid can be regenerated, and the metal recovered, to provide an economic, efficient process.

  17. Extracting metals directly from metal oxides

    DOEpatents

    Wai, C.M.; Smart, N.G.; Phelps, C.

    1997-02-25

    A method of extracting metals directly from metal oxides by exposing the oxide to a supercritical fluid solvent containing a chelating agent is described. Preferably, the metal is an actinide or a lanthanide. More preferably, the metal is uranium, thorium or plutonium. The chelating agent forms chelates that are soluble in the supercritical fluid, thereby allowing direct removal of the metal from the metal oxide. In preferred embodiments, the extraction solvent is supercritical carbon dioxide and the chelating agent is selected from the group consisting of {beta}-diketones, halogenated {beta}-diketones, phosphinic acids, halogenated phosphinic acids, carboxylic acids, halogenated carboxylic acids, and mixtures thereof. In especially preferred embodiments, at least one of the chelating agents is fluorinated. The method provides an environmentally benign process for removing metals from metal oxides without using acids or biologically harmful solvents. The chelate and supercritical fluid can be regenerated, and the metal recovered, to provide an economic, efficient process. 4 figs.

  18. Asymmetric cyanation of imines via dipeptide-derived organophosphine dual-reagent catalysis.

    PubMed

    Wang, Hong-Yu; Zheng, Chang-Wu; Chai, Zhuo; Zhang, Jia-Xing; Zhao, Gang

    2016-01-01

    Over the past few decades, enantioselective phosphine organocatalysis has evolved rapidly into a highly efficient catalytic strategy for a range of useful reactions. However, as restricted by the traditional catalytic modes, some important reactions, such as asymmetric Strecker-type reactions, have thus far been out of reach of this strategy. Reported herein is an application of enantioselective phosphine organocatalysis for asymmetric Strecker-type reactions, enabled by a dual-reagent catalyst system in which the key organophosphorus zwitterion intermediate, generated in situ by mixing a chiral dipeptide-derived multifunctional organophosphine with methyl acrylate, is used as a highly efficient chiral Lewis base catalyst. The high efficiency of this catalytic system is demonstrated in the asymmetric cyanation of isatin-derived ketimines and azomethine aldimines as well as in the kinetic resolution of racemic 3-substituted azomethines. Mechanistic studies provide experimental evidence for the intermediacy of the putative zwitterion and its role as a catalytically active Lewis base. PMID:27625043

  19. Asymmetric cyanation of imines via dipeptide-derived organophosphine dual-reagent catalysis

    NASA Astrophysics Data System (ADS)

    Wang, Hong-Yu; Zheng, Chang-Wu; Chai, Zhuo; Zhang, Jia-Xing; Zhao, Gang

    2016-09-01

    Over the past few decades, enantioselective phosphine organocatalysis has evolved rapidly into a highly efficient catalytic strategy for a range of useful reactions. However, as restricted by the traditional catalytic modes, some important reactions, such as asymmetric Strecker-type reactions, have thus far been out of reach of this strategy. Reported herein is an application of enantioselective phosphine organocatalysis for asymmetric Strecker-type reactions, enabled by a dual-reagent catalyst system in which the key organophosphorus zwitterion intermediate, generated in situ by mixing a chiral dipeptide-derived multifunctional organophosphine with methyl acrylate, is used as a highly efficient chiral Lewis base catalyst. The high efficiency of this catalytic system is demonstrated in the asymmetric cyanation of isatin-derived ketimines and azomethine aldimines as well as in the kinetic resolution of racemic 3-substituted azomethines. Mechanistic studies provide experimental evidence for the intermediacy of the putative zwitterion and its role as a catalytically active Lewis base.

  20. A comprehensive study of olefin metathesis catalyzed by Ru-based catalysts

    PubMed Central

    2015-01-01

    Summary During a Ru-catalyzed reaction of an olefin with an alkylidene moiety that leads to a metallacycle intermediate, the cis insertion of the olefin can occur from two different directions, namely side and bottom with respect to the phosphine or N-heterocyclic ligand (NHC), depending on the first or second generation Grubbs catalyst. Here, DFT calculations unravel to which extent the bottom coordination of olefins with respect is favored over the side coordination through screening a wide range of catalysts, including first and second generation Grubbs catalysts as well as the subsequent Hoveyda derivatives. The equilibrium between bottom and side coordination is influenced by sterics, electronics, and polarity of the solvent. The side attack is favored for sterically less demanding NHC and/or alkylidene ligands. Moreover the generation of a 14-electron species is also discussed, with either pyridine or phosphine ligands to dissociate. PMID:26664596