Sample records for phosphines

  1. Molecular Structure of Phosphine

    NSDL National Science Digital Library

    2003-06-04

    Phosphine, also known as phosphane, hydrogen phosphide, or phosphorus hydride, is a toxic gas for insects (and humans) and has an odor of decaying fish. Phosphine is an air pollutant and a natural product of swamps and sewers. It is used as a grain fumigant and as an insecticide for fumigation of animal feed, leaf stored tobacco, box cars, and for rodent control. Phosphine is also widely employed as an industrial gas in silicon chip manufacture, in explosives, friction matches, fireworks, toothpaste, and detergents.

  2. [Occupational phosphine poisoning].

    PubMed

    Kurzbauer, H; Kiesler, A

    1987-01-01

    The authors report their observations on late sequelae of phosphine poisoning. For 18 months after acute poisoning signs of nervous system damage persisted (objective changes, EEG abnormalities). PMID:3444514

  3. Phosphonate–phosphinate rearrangement.

    PubMed

    Qian, Renzhe; Roller, Alexander; Hammerschmidt, Friedrich

    2015-01-16

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

  4. 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

  5. 40 CFR 180.225 - Phosphine; tolerances for residues.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...false Phosphine; tolerances for residues. 180.225 Section 180.225...EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Specific Tolerances § 180.225 Phosphine; tolerances for residues. (a) General. (1)...

  6. Disruption of Iron Homeostasis Increases Phosphine Toxicity in Caenorhabditis elegans

    E-print Network

    Hammock, Bruce D.

    , the precise mode of phosphine action is unclear. In this report, we demonstrate the following dose aerobic organisms and is a gas under standard conditions. Due to a density similar to air, phosphine can

  7. Disruption of Iron Homeostasis Increases Phosphine Toxicity in Caenorhabditis elegans

    Microsoft Academic Search

    Ubon Cha; Nicholas Valmas; Patrick J. Collins; Paul E. B. Reilly; Bruce D. Hammock; Paul R. Ebert

    2007-01-01

    The aim of this study is to identify the biochemical mechanism of phosphine toxicity and resistance, using Caenorhabditis elegans as a model organism. To date, the precise mode of phosphine action is unclear. In this report, we demonstrate the following dose-dependent actions of phosphine, in vitro: (1) reduction of ferric iron (Fe3+) to ferrous iron (Fe2+), (2) release of iron

  8. Michael-type addition of secondary phosphine oxides to (1,4-cyclohexadien-3-yl)phosphine oxides.

    PubMed

    Stankevi?, Marek; Jakli?ska, Magdalena; Pietrusiewicz, K Micha?

    2012-02-17

    Base-induced reaction between (1,4-cyclohexadien-3-yl)phosphine oxides and secondary phosphine oxides gives 3,4-bis(phosphinoyl)cyclohexenes and 2,3-bis(phosphinoyl)cyclohexenes through an in situ isomerization of one of the cyclohexadienyl double bonds and a subsequent Michael-type addition of the secondary phosphine oxide. PMID:22292492

  9. Benz­yl(meth­yl)phosphinic acid

    PubMed Central

    Fougère, Cécile; Guénin, Erwann; Retailleau, Pascal; Barbey, Carole

    2010-01-01

    The title compound, C8H11O2P, is a phosphinic compound with a tetra­coordinate penta­valent P atom. The phosphinic function plays a predominant role in the cohesion of the crystal structure, both by forming chains along the b axis via strong inter­molecular O—H?O hydrogen bonds and by cross-linking these chains perpendicularly via weak inter­molecular C—H?O hydrogen bonds, generating a two-dimensional network parallel to (001). PMID:21587997

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

    SciTech Connect

    Angelov, C.M.; Neilson, R.H. (Texas Christian Univ., Fort Worth (United States))

    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

  11. Exposure to Syngas with Phosphine Contaminant

    Microsoft Academic Search

    Oktay Demircan; Chunchuan Xu; John Zondlo; Harry O. Finklea

    Solid Oxide Fuel Cells (SOFCs) represent an option to provide bridging technology for energy conversion (coal syngas) as well as a long-term technology (hydrogen from biomass). Whether the fuel is coal syngas or hydrogen from biomass, the effect of impurities on the performance of the anode is a vital question. The anode resistivity during SOFC operation with phosphine-contaminated syngas was

  12. Phosphine-catalyzed construction of sulfur heterocycles.

    PubMed

    Gabillet, Sandra; Lecerclé, Delphine; Loreau, Olivier; Carboni, Michael; Dézard, Sophie; Gomis, Jean-Marie; Taran, Frédéric

    2007-09-27

    A simple and efficient method for constructing sulfur heterocycles was developed using a phosphine-catalyzed tandem umpolung addition and intramolecular cyclization of bifunctional sulfur pronucleophiles on arylpropiolates. The reaction offers a promising route to synthetically useful as well as biologically active heterocycles under neutral conditions. PMID:17803312

  13. Synthesis and biological applications of phosphinates and derivatives.

    PubMed

    Virieux, David; Volle, Jean-Noël; Bakalara, Norbert; Pirat, Jean-Luc

    2015-01-01

    This review first outlines general considerations on phosphinic acids and derivatives as bioisosteric groups. The next sections present key aspects of phosphinic acid-based molecules and include a brief description of the biological pathways involved for their activities. The synthetic aspects and the biological activities of such compounds reported in the literature between 2008 and 2013 are also described. PMID:25467530

  14. Synthesis and characterization of telechelic phosphine oxide polyesters and cobalt(II) chloride complexes

    Microsoft Academic Search

    Qin Lin; Serkan Unal; Ann R. Fornof; R. Scott Armentrout; Timothy E. Long

    2006-01-01

    A monofunctional phosphine oxide containing endcapping reagent, 4-carboxyphenyl biphenyl phosphine oxide, was synthesized for the preparation of telechelic polyester oligomers. The chemical structure of the endcapping reagent was verified using NMR spectroscopy, mass spectroscopy, and elemental analysis. Phosphine oxide telechelic polyesters were prepared for the first time via copolymerization of a low molar mass polyester oligomer precursor and the phosphine

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

    PubMed

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

    2013-11-01

    Ambient levels of phosphine (PH3) in the air, phosphine emission fluxes from paddy fields and rice plants, and the distribution of matrix-bound phosphine (MBP) in paddy soils were investigated throughout the growing stages of rice. The relationships between MBP and environmental factors were analyzed to identify the principal factors determining the distribution of MBP. The phosphine ambient levels ranged from 2.368±0.6060 ng m(-3) to 24.83±6.529 ng m(-3) and averaged 14.25±4.547 ng m(-3). The highest phosphine emission flux was 22.54±3.897 ng (m(2)h)(-1), the lowest flux was 7.64±4.83 ng (m(2)h)(-1), and the average flux was 14.17±4.977 ng (m(2)h)(-1). Rice plants transport a significant portion of the phosphine emitted from the paddy fields. The highest contribution rate of rice plants to the phosphine emission fluxes reached 73.73% and the average contribution was 43.00%. The average MBP content of 111.6 ng kg(-1)fluctuated significantly in different stages of rice growth and initially increased then decreased with increasing depth. The peak MBP content in each growth stage occurred approximately 10 cm under the surface of paddy soils. Pearson correlation analyses and stepwise multiple regression analysis showed that soil temperature (Ts), acid phosphatase (ACP) and total phosphorus (TP) were the principal environmental factors, with correlative rankings of Ts>ACP>TP. PMID:23876504

  16. 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.

  17. A core metabolic enzyme mediates resistance to phosphine gas.

    PubMed

    Schlipalius, David I; Valmas, Nicholas; Tuck, Andrew G; Jagadeesan, Rajeswaran; Ma, Li; Kaur, Ramandeep; Goldinger, Anita; Anderson, Cameron; Kuang, Jujiao; Zuryn, Steven; Mau, Yosep S; Cheng, Qiang; Collins, Patrick J; Nayak, Manoj K; Schirra, Horst Joachim; Hilliard, Massimo A; Ebert, Paul R

    2012-11-01

    Phosphine is a small redox-active gas that is used to protect global grain reserves, which are threatened by the emergence of phosphine resistance in pest insects. We find that polymorphisms responsible for genetic resistance cluster around the redox-active catalytic disulfide or the dimerization interface of dihydrolipoamide dehydrogenase (DLD) in insects (Rhyzopertha dominica and Tribolium castaneum) and nematodes (Caenorhabditis elegans). DLD is a core metabolic enzyme representing a new class of resistance factor for a redox-active metabolic toxin. It participates in four key steps of core metabolism, and metabolite profiles indicate that phosphine exposure in mutant and wild-type animals affects these steps differently. Mutation of DLD in C. elegans increases arsenite sensitivity. This specific vulnerability may be exploited to control phosphine-resistant insects and safeguard food security. PMID:23139334

  18. Oxygen enhances phosphine toxicity for postharvest pest control.

    PubMed

    Liu, Yong-Biao

    2011-10-01

    Phosphine fumigations under superatmospheric oxygen levels (oxygenated phosphine fumigations) were significantly more effective than the fumigations under the normal 20.9% atmospheric oxygen level against western flower thrips [Frankliniella occidentalis (Pergande)] adults and larvae, leafminer Liriomyza langei Frick pupae, grape mealybug [Pseudococcus maritimus (Ehrhorn)] eggs, and Indianmeal moth [Plodia interpunctella (Hübner)] eggs and pupae. In 5-h fumigations with 1,000 ppm phosphine at 5 degrees C, mortalities of western flower thrips increased significantly from 79.5 to 97.7% when oxygen was increased from 20.9 to 40% and reached 99.3% under 80% O2. Survivorships of leafminer pupae decreased significantly from 71.2% under 20.9% O2 to 16.2% under 40% O2 and reached 1.1% under 80% O2 in 24-h fumigations with 500 ppm phosphine at 5 degrees C. Complete control of leafminer pupae was achieved in 24-h fumigations with 1,000 ppm phosphine at 5 degrees C under 60% O2 or higher. Survivorships of grape mealybug eggs also decreased significantly in 48-h fumigations with 1,000 ppm phosphine at 2 degrees C under 60% O2 compared with the fumigations under 20.9% O2. Indian meal moth egg survivorships decreased significantly from 17.4 to 0.5% in responses to an oxygen level increase from 20.9 to 40% in 48-h fumigations with 1,000 ppm phosphine at 10 degrees C and reached 0.2% in fumigations under 80% O2. When the oxygen level was reduced from 20.9 to 15 and 10% in fumigations, survivorships of Indianmeal moth eggs increased significantly from 17.4 to 32.9 and 39.9%, respectively. Increased O2 levels also resulted in significantly lower survival rates of Indianmeal moth pupae in response to 24-h fumigations with 500 and 1,000 ppm phosphine at 10 degrees C and a complete control was achieved in the 1,000 ppm phosphine fumigations under 60% O2. Oxygenated phosphine fumigations have marked potential to improve insecticidal efficacy. Advantages and limitations of oxygenated phosphine fumigation are discussed. PMID:22066172

  19. Imide/Arylene Ether Copolymers Containing Phosphine Oxide

    NASA Technical Reports Server (NTRS)

    Jensen, Brian J.; Partos, Richard D.

    1993-01-01

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

  20. Unintentional poisoning by phosphine released from aluminum phosphide

    Microsoft Academic Search

    S Shadnia; O Mehrpour; M Abdollahi

    2008-01-01

    Aluminum phosphide as a releaser of phosphine gas is used as a grain preservative. In this case report, we describe an accidental severe poisoning in a 35-year-old woman, her 18-year-old daughter, and 6-year-old son caused by inhalation of phosphine gas released from 20 tablets of aluminum phosphide stored in 15 rice bags. The boy died 2?days after exposure before admission

  1. Diphosphine Dioxide Cages and Hydrogen Peroxide Adducts of Phosphine Oxides: Syntheses and Applications in Surface Science 

    E-print Network

    Hilliard, Casie Renee

    2013-12-09

    Understanding the adsorption of phosphine oxides on silica surfaces has a threefold incentive. (a) Efficiently removing phosphine oxides from reaction mixtures is crucial after many synthetic procedures, for example the ...

  2. The synthesis and applications of a biaryl-based asymmetric phosphine ligand

    E-print Network

    Hirai, Satoko

    2005-01-01

    The asymmetric biaryl backbone of a dialkylbiphenyl phosphine ligand was developed, synthesized, and resolved. The application of the chiral phosphine ligand to the asymmetric Suzuki-Miyaura cross-coupling reaction was ...

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

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...Phosphinic acid, P,P-diethyl-, zinc salt (2:1). 721.10135 Section 721...Phosphinic acid, P,P-diethyl-, zinc salt (2:1). (a) Chemical substance...phosphinic acid, P,P-diethyl-, zinc salt (2:1) (PMN P-05-11; CAS...

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

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...Phosphinic acid, P,P-diethyl-, zinc salt (2:1). 721.10135 Section 721...Phosphinic acid, P,P-diethyl-, zinc salt (2:1). (a) Chemical substance...phosphinic acid, P,P-diethyl-, zinc salt (2:1) (PMN P-05-11; CAS...

  5. 40 CFR 721.10135 - Phosphinic acid, P,P-diethyl-, zinc salt (2:1).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...Phosphinic acid, P,P-diethyl-, zinc salt (2:1). 721.10135 Section 721...Phosphinic acid, P,P-diethyl-, zinc salt (2:1). (a) Chemical substance...phosphinic acid, P,P-diethyl-, zinc salt (2:1) (PMN P-05-11; CAS...

  6. 40 CFR 721.10135 - Phosphinic acid, P,P-diethyl-, zinc salt (2:1).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...Phosphinic acid, P,P-diethyl-, zinc salt (2:1). 721.10135 Section 721...Phosphinic acid, P,P-diethyl-, zinc salt (2:1). (a) Chemical substance...phosphinic acid, P,P-diethyl-, zinc salt (2:1) (PMN P-05-11; CAS...

  7. 40 CFR 721.10135 - Phosphinic acid, P,P-diethyl-, zinc salt (2:1).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...Phosphinic acid, P,P-diethyl-, zinc salt (2:1). 721.10135 Section 721...Phosphinic acid, P,P-diethyl-, zinc salt (2:1). (a) Chemical substance...phosphinic acid, P,P-diethyl-, zinc salt (2:1) (PMN P-05-11; CAS...

  8. Unintentional poisoning by phosphine released from aluminum phosphide.

    PubMed

    Shadnia, S; Mehrpour, O; Abdollahi, M

    2008-01-01

    Aluminum phosphide as a releaser of phosphine gas is used as a grain preservative. In this case report, we describe an accidental severe poisoning in a 35-year-old woman, her 18-year-old daughter, and 6-year-old son caused by inhalation of phosphine gas released from 20 tablets of aluminum phosphide stored in 15 rice bags. The boy died 2 days after exposure before admission to hospital and any special treatment, but the others were admitted 48 h after exposure. They had signs and symptoms of severe toxicity, and their clinical course included metabolic acidosis, electrocardiographic changes, and hypotension. They were treated by intravenous administration of sodium bicarbonate, magnesium sulfate, and calcium gluconate. The patients were discharged after 3 days and followed up for 1 week after discharge. Rapid absorption of phosphine by inhalation, induction of hyperglycemia, and surviving of patients are interesting issues of this case report. PMID:18480154

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

    Microsoft Academic Search

    Nicholas Valmas; Paul R. Ebert; Debbie Fox

    2006-01-01

    BackgroundWith 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

  10. Formation of Phenylene Oligomers Using Platinum-Phosphine Complexes

    E-print Network

    Jones, William D.

    Formation of Phenylene Oligomers Using Platinum-Phosphine Complexes Nira Simhai, Carl N. Iverson to the formation of two strong metal-aryl bonds. This is demonstrated by the reaction of biphenylene with (C5Me5)Rh, R. H.; Dion, R. P.; Gibboni, D. J.; McGrath, D. V.; Holt, E. M. J. Am. Chem. Soc. 1986, 108, 7222

  11. Adsorption Sampling of Phosphine and Some Other Semiconductor Material Gases

    Microsoft Academic Search

    Yoshimi Matsumura; Mariko Ono-Ogasawara; Mitsuya Furusey

    1993-01-01

    The adsorption sampling methods of airborne diborane, phosphine, arsine, and silane for the monitoring of workplaces of advanced industries such as the manufacturers of semiconductor integrated circuits and fine ceramics were studied. As those gases are highly toxic and their threshold limit values recommended by American Conference of Governmental Industrial Hygienists are very low, the sampling methods and the successive

  12. A phosphine-catalyzed preparation of 4-arylidene-5-imidazolones.

    PubMed

    Gabillet, Sandra; Loreau, Olivier; Specklin, Simon; Rasalofonjatovo, Evelia; Taran, Frédéric

    2014-10-17

    A simple and efficient method for constructing 4-arylidene-5-imidazolones was developed using a phosphine-catalyzed tandem umpolung addition and intramolecular cyclization of amidine pronucleophiles on arylpropiolates. The reaction offers a robust route to heterocycle analogues of the fluorescent protein chromophores. PMID:25238600

  13. 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. PMID:25980800

  14. Physiological and biochemical responses of rice seeds to phosphine exposure during germination.

    PubMed

    Niu, Xiaojun; Mi, Lina; Li, Yadong; Wei, Aishu; Yang, Zhiquan; Wu, Jiandong; Zhang, Di; Song, Xiaofei

    2013-11-01

    Rice seeds (Tianyou, 3618) were used to examine the physiological and biochemical responses to phosphine exposure during germination. A control (0 mg m(-3)) and four concentrations of phosphine (1.4 mg m(-3), 4.2 mg m(-3), 7.0 mg m(-3) and 13.9 mg m(-3)) were used to treat the rice seeds. Each treatment was applied for 90 min once per day for five days. The germination rate (GR); germination potential (GP); germination index (GI); antioxidant enzymes, including superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT); and lipid peroxidation measured through via malondialdehyde (MDA) were determined as indicators of the physiological and biochemical responses of the rice seeds to phosphine exposure. These indicators were determined once per day for five days. The results indicated that the GR, GP and GI of the rice seeds markedly decreased after phosphine exposure. The changes in the activities of the antioxidant enzymes due to the phosphine exposure were also significant. The exposure lowered the CAT and SOD activities and increased POD activity in the treated rice seeds compared with controls. The MDA content exhibited a slow increase trend with the increase of phosphine concentration. These results suggest that phosphine has inhibitory effects on seed germination. In addition, phosphine exposure caused oxidative stress in the seeds. The antioxidant enzymes could play a pivotal role against oxidative injury. Overall, the effect of phosphine on rice seeds is different from what has been reported previously for insects and mammals. PMID:23992639

  15. 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.

  16. Hydrogen Bonding in Phosphine Oxide\\/Phosphate-Phenol Complexes

    Microsoft Academic Search

    Ruud Cuypers; Ernst J. R. Sudhölter; Han Zuilhof

    2010-01-01

    To develop a new solvent-impregnated resin (SIR) system for the removal of phenols and thiophenols from water, complex formation by hydrogen bonding of phosphine oxides and phosphates is studied using isothermal titration calorimetry (ITC) and quantum chemical modeling. Six different computational methods are used: B3LYP, M06-2X, MP2, spin component-scaled (SCS) MP2 [all four with 6-311+G(d,p) basis set], a complete basis

  17. Selective dehydrocoupling of phosphines by lithium chloride carbenoids.

    PubMed

    Molitor, Sebastian; Becker, Julia; Gessner, Viktoria H

    2014-11-01

    The development of a simple, transition-metal-free approach for the formation of phosphorus-phosphorus bonds through dehydrocoupling of phosphines is presented. The reaction is mediated by electronically stabilized lithium chloride carbenoids and affords a variety of different diphosphines under mild reaction conditions. The developed protocol is simple and highly efficient and allows the isolation of novel functionalized diphosphines in high yields. PMID:25322474

  18. Photoinduced reductive perfluoroalkylation of phosphine oxides: synthesis of P-perfluoroalkylated phosphines using TMDPO and perfluoroalkyl iodides.

    PubMed

    Sato, Yuki; Kawaguchi, Shin-Ichi; Ogawa, Akiya

    2015-06-16

    A photoinduced reaction between TMDPO (diphenyl(2,4,6-trimethylbenzoyl)-phosphine oxide) and perfluoroalkyl iodides successfully affords P-(perfluoroalkyl)diphenylphosphines as promising ligands for recyclable catalysts. Interestingly, the perfluoroalkylation reaction involves the reduction of phosphorus(v) compounds to phosphorus(iii) species. The advantages of the present reaction include the use of an air-stable phosphorus source and good yields of P-perfluoroalkylphosphines in short reaction times. PMID:26041689

  19. 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…

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

    PubMed

    Liu, Yong-Biao; Liu, Samuel S; Simmons, Gregory; Walse, Spencer S; Myers, Scott W

    2013-08-01

    Light brown apple moth, Epiphyas postvittana (Walker), eggs were subjected to phosphine fumigations under normal atmospheric and elevated oxygen levels in laboratory-scale chamber experiments to compare their susceptibilities to the two different fumigation methods. In fumigations conducted under atmospheric oxygen at 5 and 10 degrees C, egg survivorship decreased with increase in phosphine concentration but then increased at a concentration of 3,000 ppm; this increase was significant at 10 degrees C. Based on egg survivorship data, phosphine fumigations conducted in a 60% oxygen atmosphere were significantly more effective than those conducted under atmospheric oxygen conditions. Oxygenated phosphine fumigations at 5 and 10 degrees C killed all 1,998 and 2,213 E. postvittana eggs treated, respectively, after 72 h of exposure. These results indicate the great potential of oxygenated phosphine fumigation for the control of E. postvittana eggs. PMID:24020273

  1. 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.

  2. 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

  3. 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. PMID:25195424

  4. Intermolecular zirconium-catalyzed hydrophosphination of alkenes and dienes with primary phosphines.

    PubMed

    Ghebreab, Michael B; Bange, Christine A; Waterman, Rory

    2014-07-01

    Catalytic hydrophosphination of terminal alkenes and dienes with primary phosphines (RPH2; R = Cy, Ph) under mild conditions has been demonstrated using a zirconium complex, [?(5)-N,N,N,N,C-(Me3SiNCH2CH2)2NCH2CH2NSiMe2CH]Zr (1). Exclusively anti-Markovnikov functionalized products were observed, and the catalysis is selective for either the secondary or tertiary phosphine (i.e., double hydrophosphination) products, depending on reaction conditions. The utility of the secondary phosphine products as substrates for further elaboration was demonstrated with a platinum-catalyzed asymmetric alkylation reaction. PMID:24937212

  5. Synthesis and characterization of novel polyimides containing fluorine and phosphine oxide moieties

    Microsoft Academic Search

    K. U Jeong; J.-J Kim; T.-H Yoon

    2001-01-01

    A novel diamine monomer, containing fluorine and phosphine oxide, bis(3-aminophenyl)-3,5-bis(trifluoromethyl)phenyl phosphine oxide (mDA6FPPO), was prepared via Grignard reaction from diphenylphosphonic chloride and 3,5-bis(trifluoromethyl)bromobenzene. First, 3,5-bis(trifluoromethyl)phenyl diphenyl phosphine oxide (6FPPO) was prepared and subjected to nitration and reduction to obtain mDA6FPPO. The monomers were characterized by FT-IR, 1H-NMR, 31P-NMR, 19F-NMR, titrator and elemental analyzer (EA). The monomer was then utilized to

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

    SciTech Connect

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

    1988-06-01

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

  7. Features of hydroformylation in the presence of a rhodium complex with a macromolecular phosphine ligand

    SciTech Connect

    Imyanitov, N.S.; Tupitsyn, S.B. [VNIINeftekhim, St Petersburg (Russian Federation)

    1993-12-31

    In the present paper a quantitative comparison is made of the catalytic activity and regioselectivity in 1-dodecene hydroformylation of complexes of rhodium with triphenylphosphine and with phosphinated polystyrene dissolved in the reaction medium. 22 refs., 4 figs., 2 tabs.

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

    DOEpatents

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

    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.

  9. Biosynthesis of phosphonic and phosphinic acid natural products.

    PubMed

    Metcalf, William W; van der Donk, Wilfred A

    2009-01-01

    Natural products containing carbon-phosphorus bonds (phosphonic and phosphinic acids) have found widespread use in medicine and agriculture. Recent years have seen a renewed interest in the biochemistry and biology of these compounds with the cloning of the biosynthetic gene clusters for several family members. This review discusses the commonalities and differences in the molecular logic that lie behind the biosynthesis of these compounds. The current knowledge regarding the metabolic pathways and enzymes involved in the production of a number of natural products, including the approved antibiotic fosfomycin, the widely used herbicide phosphinothricin (PT), and the clinical candidate for treatment of malaria FR-900098, is presented. Many of the enzymes involved in the biosynthesis of these compounds catalyze chemically and biologically unprecedented transformations, and a wealth of new biochemistry has been revealed through their study. These investigations have also suggested new strategies for natural product discovery. PMID:19489722

  10. 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.

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

    PubMed Central

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

    2014-01-01

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

  12. Phosphine-promoted cross-coupling reactions of propargylcopper reagents and alkenyl iodides and the total synthesis of (-)-gloeosporone via nickel-catalyzed epoxide-alkyne reductive macrocyclization

    E-print Network

    Trenkle, James D. (James Douglas)

    2007-01-01

    I. Phosphine-Promoted Cross-Coupling Reactions of Propargylcopper Alkenyl Iodides Reagents and Alkenyl Iodides. An electron-rich phosphine additive is critical and sufficient for propargyl-selective couplings of propargylcopper ...

  13. Hydrogen bonding in phosphine oxide/phosphate-phenol complexes.

    PubMed

    Cuypers, Ruud; Sudhölter, Ernst J R; Zuilhof, Han

    2010-07-12

    To develop a new solvent-impregnated resin (SIR) system for the removal of phenols and thiophenols from water, complex formation by hydrogen bonding of phosphine oxides and phosphates is studied using isothermal titration calorimetry (ITC) and quantum chemical modeling. Six different computational methods are used: B3LYP, M06-2X, MP2, spin component-scaled (SCS) MP2 [all four with 6-311+G(d,p) basis set], a complete basis set extrapolation at the MP2 level (MP2/CBS), and the composite CBS-Q model. This reveals a range of binding enthalpies (DeltaH) for phenol-phosphine oxide and phenol-phosphate complexes and their thio analogues. Both structural (bond lengths/angles) and electronic elements (charges, bond orders) are studied. Furthermore, solvent effects are investigated theoretically by the PCM solvent model and experimentally via ITC. From our calculations, a trialkylphosphine oxide is found to be the most promising extractant for phenol in SIRs, yielding DeltaH=-14.5 and -9.8 kcal mol(-1) with phenol and thiophenol, respectively (MP2/CBS), without dimer formation that would hamper the phenol complexation. In ITC measurements, the DeltaH of this complex was most negative in the noncoordinating solvent cyclohexane, and slightly less so in pi-pi interacting solvents such as benzene. The strongest binding is found for the dimethyl phosphate-phenol complex [-15.1 kcal mol(-1) (MP2/CBS)], due to the formation of two H-bonds (P=OH-O- and P-O-HO-H); however, dimer formation of these phosphates competes with complexation of phenol, and would thus hamper their use in industrial extractions. CBS-Q calculations display erroneous trends for sulfur compounds, and are found to be unsuitable. Computationally relatively cheap SCS-MP2 and M06-2X calculations did accurately agree with the much more elaborate MP2/CBS method, with an average deviation of less than 1 kcal mol(-1). PMID:20602407

  14. 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.

  15. 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.

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

    PubMed

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

    2015-09-01

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

  17. Carbonylation of ethene catalysed by Pd(II)-phosphine complexes.

    PubMed

    Cavinato, Gianni; Toniolo, Luigi

    2014-01-01

    This review deals with olefin carbonylation catalysed by Pd(II)-phosphine complexes in protic solvents. In particular, the results obtained in the carbonylation with ethene are reviewed. After a short description of the basic concepts relevant to this catalysis, the review treats in greater details the influence of the bite angle, skeletal rigidity, electronic and steric bulk properties of the ligand on the formation of the products, which range from high molecular weight perfectly alternating polyketones to methyl propanoate. It is shown that the steric bulk plays a major role in directing the selectivity. Particular emphasis is given to the factors governing the very active and selective catalysis to methyl propanoate, including the mechanism of the catalytic cycles with diphosphine- and monophosphine-catalysts. A brief note on the synthesis of methyl propanoate using a "Lucite" type catalyst in ionic liquids is also illustrated. A chapter is dedicated to the carbonylation of olefins in aqueous reaction media. The nonalternating CO-ethene copolymerization is also treated. PMID:25247684

  18. 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

  19. 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. PMID:22928286

  20. Phosphonates and phosphinates: novel leaving groups for benzisothiazolone inhibitors of human leukocyte elastase.

    PubMed

    Desai, R C; Court, J C; Ferguson, E; Gordon, R J; Hlasta, D J; Dunlap, R P; Franke, C A

    1995-04-28

    A novel class of alkyl and aryl phosphonate and phosphinate acid-based leaving groups has been developed for utilization in the synthesis of benzoisothiazolone (BIT) inhibitors of human leukocyte elastase (HLE). A number of BITs were synthesized with phosphonate and phosphinate acid-based leaving groups and were found to be potent inhibitors of HLE. Compound 3c with a diethyl phosphonate leaving group is the most potent inhibitor synthesized in this series with Ki* = 0.035 nM and ED50 = 2.0 mg/kg. PMID:7739015

  1. 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?? aromatic intra- and inter­molecular inter­actions. PMID:21579222

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

    PubMed Central

    Andrews, Ian P.

    2012-01-01

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

  3. Phosphine-iminopyridines as platforms for catalytic hydrofunctionalization of alkenes.

    PubMed

    Gilbert-Wilson, Ryan; Chu, Wan-Yi; Rauchfuss, Thomas B

    2015-06-01

    A series of phosphine-diimine ligands were synthesized by the condensation of 2-(diphenylphosphino)aniline (PNH2) with a variety of formyl and ketopyridines. Condensation of PNH2 with acetyl- and benzoylpyridine yielded the Ph2P(C6H4)N?C(R)(C5H4N), respectively abbreviated PN(Me)py and PN(Ph)py. With ferrous halides, PN(Ph)py gave the complexes FeX2(PN(Ph)py) (X = Cl, Br). Condensation of pyridine carboxaldehyde and its 6-methyl derivatives with PNH2 was achieved using a ferrous template, affording low-spin complexes [Fe(PN(H)py(R))2](2+) (R = H, Me). Dicarbonyls Fe(PN(R)py)(CO)2 were produced by treating PN(Me)py with Fe(benzylideneacetone)(CO)3 and reduction of FeX2(PN(Ph)py) with NaBEt3H under a CO atmosphere. Cyclic voltammetric studies show that the [FeL3(CO)2](0/-) and [FeL3(CO)2](+/0) couples are similar for a range of tridentate ligands, but the PN(Ph)py system uniquely sustains two one-electron reductions. Treatment of Fe(PN(Ph)py)X2 with NaBEt3H gave active catalysts for the hydroboration of 1-octene with pinacolborane. Similarly, these catalysts proved active for the addition of diphenylsilane, but not HSiMe(OSiMe3)2, to 1-octene and vinylsilanes. Evidence is presented that catalysis occurs via iron hydride complexes of intact PN(Ph)py. PMID:25978588

  4. 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.

  5. 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.

  6. Inheritance and characterization of strong resistance to phosphine in Sitophilus oryzae (L.).

    PubMed

    Nguyen, Tam T; Collins, Patrick J; Ebert, Paul R

    2015-01-01

    Sitophilus oryzae (Linnaeus) is a major pest of stored grain across Southeast Asia and is of increasing concern in other regions due to the advent of strong resistance to phosphine, the fumigant used to protect stored grain from pest insects. We investigated the inheritance of genes controlling resistance to phosphine in a strongly resistant S. oryzae strain (NNSO7525) collected in Australia and find that the trait is autosomally inherited and incompletely recessive with a degree of dominance of -0.66. The strongly resistant strain has an LC50 52 times greater than a susceptible reference strain (LS2) and 9 times greater than a weakly resistant strain (QSO335). Analysis of F2 and backcross progeny indicates that two or more genes are responsible for strong resistance, and that one of these genes, designated So_rph1, not only contributes to strong resistance, but is also responsible for the weak resistance phenotype of strain QSO335. These results demonstrate that the genetic mechanism of phosphine resistance in S. oryzae is similar to that of other stored product insect pests. A unique observation is that a subset of the progeny of an F1 backcross generation are more strongly resistant to phosphine than the parental strongly resistant strain, which may be caused by multiple alleles of one of the resistance genes. PMID:25886629

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

    NASA Astrophysics Data System (ADS)

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

    2014-07-01

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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  9. A phosphine-mediated construction of 1,4-oxazepines and 1,3-oxazines.

    PubMed

    François-Endelmond, Céline; Carlin, Thomas; Thuery, Pierre; Loreau, Olivier; Taran, Frédéric

    2010-01-01

    A simple and efficient method for constructing 1,4-oxazepines and 1,3-oxazines was developed with use of a phosphine-mediated tandem reaction of ynones with 2-azido alcohols. The method offers a promising route to synthetically useful as well as biologically active heterocycles under mild conditions and may be exploited for the preparation of interesting chiral ligands. PMID:20035563

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

    PubMed Central

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

    2014-01-01

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

  11. Asymmetric Carbon-Carbon Bond Formation gamma to a Carbonyl Group: Phosphine-Catalyzed Addition of Nitromethane to Allenes

    E-print Network

    Smith, Sean W.

    A chiral phosphine catalyzes the addition of a carbon nucleophile to the ? position of an electron-poor allene (amide-, ester-, or phosphonate-substituted), in preference to isomerization to a 1,3-diene, in good ee and ...

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

    PubMed

    Domkin, Vladimir; Chabes, Andrei

    2014-01-01

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

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

    SciTech Connect

    Rosario-Amorin, Daniel [University of New Mexico, Albuquerque] [University of New Mexico, Albuquerque; Ouizem, Sabrina [University of New Mexico, Albuquerque] [University of New Mexico, Albuquerque; Dickie, D. A. [University of New Mexico, Albuquerque] [University of New Mexico, Albuquerque; Paine, Robert T. [University of New Mexico, Albuquerque] [University of New Mexico, Albuquerque; Cramer, Roger E. [University of Hawaii] [University of Hawaii; Hay, Benjamin [ORNL] [ORNL; Podair, Julien [ORNL] [ORNL; Delmau, Laetitia Helene [ORNL] [ORNL

    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.

  14. 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.

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

    PubMed

    Miyake, Junpei; Watanabe, Masahiro; Miyatake, Kenji

    2013-07-10

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

  16. Immobilization and chelation of metal complexes with bifunctional phosphine ligands: a solid-state NMR study

    E-print Network

    Bluemel, Janet

    to bonding via one, two, or three siloxane bridges and there is also the possibility of cross- linking.' Therefore, we used the monoethoxy phosphine PPh2(C6H4)SiMe20Et1 that forms just one siloxane bridge when or an addition reaction to surface siloxane groups takes place.'3 This can be seen in the 29Si CP MAS NMR

  17. Extraction and separation of rare earth metals using microcapsules containing bis(2-ethylhexyl)phosphinic acid

    Microsoft Academic Search

    Syouhei Nishihama; Nobuya Sakaguchi; Takayuki Hirai; Isao Komasawa

    2002-01-01

    The separation of rare earth metals using microcapsules (MC) consisting styrene (St)–divinylbenzene (DVB) copolymer and containing bis(2-ethylhexyl)phosphinic acid (PIA-226) has been investigated. Microcapsules containing PIA-226 can be prepared by adding PIA-226 to the dispersed phase during the preparation process. The extraction of rare earth metals with the microcapsules progresses via the same scheme, as proposed in the conventional liquid–liquid extraction

  18. Extraction of rare-earth elements from nitric acid solutions with bis(dioctylphosphinylmethyl)phosphinic acid

    Microsoft Academic Search

    A. N. Turanov; V. K. Karandashev; A. N. Yarkevich; Z. V. Safronova

    2006-01-01

    The distribution of microamounts of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Y nitrates between aqueous\\u000a HNO3 solutions and solutions of bis(dioctylphosphinylmethyl)phosphinic acid in organic diluents was studied. The stoichiometry\\u000a of the extractable complexes was determined, and the diluent effect on the efficiency of extraction of rare-earth elements\\u000a from nitric acid solutions

  19. Permanent magnetism in phosphine- and chlorine-capped gold: from clusters to nanoparticles

    Microsoft Academic Search

    Miguel A. Munoz-MarquezEstefanõ; Estefanía Guerrero; Asunción Fernández; Patricia Crespo; Antonio Hernando; Raquel Lucena; José C. Conesa

    2010-01-01

    Magnetometry results have shown that gold NPs (?2 nm in size) protected with phosphine and chlorine ligands exhibit permanent\\u000a magnetism. When the NPs size decreases down to the subnanometric size range, e.g. undecagold atom clusters, the permanent\\u000a magnetism disappears. The near edge structure of the X-ray absorption spectroscopy data points out that charge transfer between\\u000a gold and the capping system

  20. Effect of Preparation Conditions on the Property Cu\\/AC Adsorbents for Phosphine Adsorption

    Microsoft Academic Search

    Qiongfen Yu; Ping Ning; Honghong Yi; Xiaolong Tang; Ming Li; Liping Yang

    2011-01-01

    Copper-based activated carbon adsorbents (Cu\\/AC) were prepared and used to investigate the effects of various copper precursors, impregnation solution concentration and calcination temperature on phosphine (PH3) adsorption removal from yellow phosphorous tail gas. N2 adsorption isotherm and X-ray Diffraction (XRD) were used for characterizing the Cu\\/AC adsorbents. It can be seen the Cu(N)\\/AC adsorbent prepared from Cu(NO3)2 precursor has higher

  1. Effect of Preparation Conditions on the Property Cu\\/AC Adsorbents for Phosphine Adsorption

    Microsoft Academic Search

    Qiongfen Yu; Ping Ning; Honghong Yi; Xiaolong Tang; Ming Li; Liping Yang

    2012-01-01

    Copper-based activated carbon adsorbents (Cu\\/AC) were prepared and used to investigate the effects of various copper precursors, impregnation solution concentration, and calcination temperature on phosphine (PH3) adsorption removal from yellow phosphorus tail gas. N2 adsorption isotherm and X-ray Diffraction (XRD) were used for characterizing the Cu\\/AC adsorbents. It can be seen that the Cu(N)\\/AC adsorbent prepared from the Cu(NO3)2 precursor

  2. Bifunctional ligands in combination with phosphines and Lewis acidic phospheniums for the carbonylative Sonogashira reaction.

    PubMed

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

    2015-06-23

    The combination of phosphine-ligated Pd catalysis and phosphenium(v) Lewis acid catalysis has been developed for the carbonylative Sonogashira reaction using phosphino-phosphenium salts () as bifunctional ligands, in which the Lewis acidic phosphenium(v) cations can form secondary bonds with O atoms (in C[double bond, length as m-dash]O) to cooperatively stabilize Pd-acyl intermediates. PMID:26055388

  3. A tris (2-carboxyethyl) phosphine (TCEP) related cleavage on cysteine-containing proteins

    Microsoft Academic Search

    Peiran Liu; Brian W. O’Mara; Bethanne M. Warrack; Wei Wu; Yunping Huang; Yihong Zhang; Rulin Zhao; Mei Lin; Michael S. Ackerman; Peter K. Hocknell; Guodong Chen; Li Tao; Siegfried Rieble; Jack Wang; David B. Wang-Iverson; Adrienne A. Tymiak; Michael J. Grace; Reb J. Russell

    2010-01-01

    Introduced in the late 1980s as a reducing reagent, Tris (2-carboxyethyl) phosphine (TCEP) has now become one of the most\\u000a widely used protein reductants. To date, only a few studies on its side reactions have been published. We report the observation\\u000a of a side reaction that cleaves protein backbones under mild conditions by fracturing the cysteine residues, thus generating\\u000a heterogeneous

  4. Spectrophotometric Assay for Hypochlorite\\/Hypochlorous Acid Using Tris(2-carboxyethyl)phosphine

    Microsoft Academic Search

    Joan Han; Teh-Ching Chu; Grace Han; John Browne; Irene Brown; Peter Han

    1998-01-01

    A simple spectrophotometric method for quantitative determination of hypochlorite (OCl?) or hypochlorous acid (HOCl) is described. The OCl?or HOCl sample is first incubated with an excess amount of tris(2-carboxyethyl)phosphine (TCEP). The concentration of the residual TCEP is then measured as the amount of 2-nitro-5-thiobenzoate produced after reaction with 5,5?-dithiobis(2-nitrobenzoic acid). The concentration of OCl?or HOCl is equivalent to the amount

  5. A Spectrophotometric Method for Quantitative Determination of Bromine Using Tris(2-carboxyethyl)phosphine

    Microsoft Academic Search

    Joan Han; Troy Story; Grace Han

    1999-01-01

    A simple spectrophotometric method for quantitative determination of bromine is described. The sample containing bromine is first incubated with an excess of tris(2-carboxyethyl)phosphine (TCEP). One molecule of TCEP is rapidly and irreversibly oxidized to TCEPO (TCEP oxide) by one molecule of bromine. The concentration of residual TCEP is then measured as 2-nitro-5-thiobenzoate produced by reaction with 5,5'-dithiobis(2-nitrobenzoic acid). This method

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

    NASA Astrophysics Data System (ADS)

    Bampoh, Victoria Naa Kwale

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

  7. 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.

  8. Theoretical Studies of Structures and Mechanisms in Organometallic and Bioinorganic Chemistry: Heck Reaction with Palladium Phosphines, Active Sites of Superoxide Reductase and Cytochrome P450 Monooxygenase, and Tetrairon Hexathiolate Hydrogenase Model 

    E-print Network

    Surawatanawong, Panida

    2010-07-14

    -addition barrier is lower on monopalladium monophosphine than dipalladium diphosphine whereas for a small phosphine, PMe3, the oxidative addition proceeds more easily via dipalladium diphosphine. Of the phosphine-free palladium complexes examined: free-Pd, Pd...

  9. New monodentate chiral phosphine 2,6-dimethyl-9-phenyl-9-phosphabicyclo[3.3.1]nonane(9-PBN): Application to asymmetric allylic substitution reaction

    Microsoft Academic Search

    Yasumasa Hamada; Noriko Seto; Hiroki Ohmori; Keiichiro Hatano

    1996-01-01

    New monodentate chiral phosphines, (+)- and (?)-2,6-dimethyl-9-phenyl-9-phosphabicyclo[3.3.1]nonanes ((+)- and (?)-9-PBNs), were prepared from 1,5-dimethyl-1,5-cyclooctadiene, and their application to the asymmetric allylic substitution reaction proved the utility of 9-PBNs as chiral phosphine ligands.

  10. Tris(tert-butyl)phosphine selenide, the missing link in tris(tert-butyl)phosphine chalcogenide structures (t)Bu(3)P==X (X = O, S, Se, Te).

    PubMed

    Steinberger, H U; Ziemer, B; Meisel, M

    2001-03-01

    In tris(tert-butyl)phosphine selenide, C(12)H(27)PSe, all the methyl ligands are disordered over two sites in the ratio 70/30. The molecule displays crystallographic C(3) symmetry. The bond angles at the P atom are distorted tetrahedral [C--P--C 110.02 (5) degrees and Se==P--C 108.91 (5) degrees ]. The P--C and P==Se bond lengths are 1.908 (1) and 2.1326 (6) A, respectively. A comparison of the structural data of the complete series of tris(tert-butyl)phosphine chalcogenides ((t)Bu(3)PO, (t)Bu(3)PS, (t)Bu(3)PSe and (t)Bu(3)PTe) with the corresponding data of other phosphine chalcogenides substituted by smaller organic groups shows the great influence of the bulky tert-butyl ligands. PMID:11250595

  11. Photoemission on gold-55-clusters derived from gold-phosphine AuP(C6H5)3Cl

    NASA Astrophysics Data System (ADS)

    Quinten, M.; Sander, I.; Steiner, P.; Kreibig, U.; Fauth, K.; Schmid, G.

    1991-03-01

    We measured XPS and UPS spectra of gold clusters with 55 atoms, embedded in an electrically isolating phosphine matrix, and of gold-phosphine, from which the clusters were chemically derived. Compared to the spectra of bulk gold the valence band spectrum and the core level spectra of the clusters showed shifts of the peaks and the fermi level to higher binding energies. The shift of the peaks could qualitatively be interpreted by a final state effect. We succeeded in a separation of bulk and surface contributions to the core level spectra and in a reasonable quantitative analysis of the valence band spectrum of the clusters. The Au 4 f core level spectrum of gold-phosphine showed two peaks at 1.5 eV higher binding energies than the corresponding peaks of the clusters.

  12. Control of morphology and crystal purity of InP nanowires by variation of phosphine flux during selective area MOMBE.

    PubMed

    Kelrich, A; Dubrovskii, V G; Calahorra, Y; Cohen, S; Ritter, D

    2015-02-27

    We present experimental results showing how the growth rate, morphology and crystal structure of Au-catalyzed InP nanowires (NWs) fabricated by selective area metal organic molecular beam epitaxy can be tuned by the growth parameters: temperature and phosphine flux. The InP NWs with 20-65 nm diameters are grown at temperatures of 420 and 480 °C with the PH3 flow varying from 1 to 9 sccm. The NW tapering is suppressed at a higher temperature, while pure wurtzite crystal structure is preferred at higher phosphine flows. Therefore, by combining high temperature and high phosphine flux, we are able to fabricate non-tapered and stacking fault-free InP NWs with the quality that other methods rarely achieve. We also develop a model for NW growth and crystal structure which explains fairly well the observed experimental tendencies. PMID:25648852

  13. Hydrogen bond network structures based on sulfonated phosphine ligands: The effects of complex geometry, cation substituents and phosphine oxidation on guanidinium sulfonate sheet formation

    Microsoft Academic Search

    Nichola J. Burke; Andrew D. Burrows; Mary F. Mahon; John E. Warren

    2006-01-01

    Interactions between guanidinium cations and the sulfonate groups on the phosphine [PPh2C6H4-m-SO3]? have been exploited to incorporate iridium(I) centres into hydrogen-bonded networks. The crystal structure of [C(NH2)3]2{trans-[IrCl(CO)(PPh2C6H4-m-SO3)2]} (4) contains hexagonal guanidinium sulfonate (GS) sheets in which both of the sulfonate groups from each complex anion form hydrogen bonds within the same sheet. The crystal structures of [C(NH2)2(NHMe)][PPh2C6H4-m-SO3] (5) and [C(NH2)2(NHEt)][PPh2C6H4-m-SO3

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

    PubMed

    Wambach, Truman C; Fryzuk, Michael D

    2015-06-15

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

  15. Chemistry of tris(2,4,6-trimethoxyphenyl)phosphine with rhodium(I) and iridium(I) olefin complexes

    Microsoft Academic Search

    Kim R. Dunbar; Steven C. Haefner; Calvin E. Uzelmeier; Anthony Howard

    1995-01-01

    Rh(I) and Ir(I) complexes of the type [Rh(cod)(?2-TMPP)]1+ (1) and M(cod)(?2-TMPP-O) (M = Rh (2), Ir (3); cod = cyclooctadiene; TMPP = tris(2,4,6-trimethoxyphenyl)phosphine; TMPP-O = mono-demethylated form of TMPP) have been isolated from reactions of [M(cod)Cl]2 with M?BF4 (M? = Ag+, K+, Na+) followed by addition of the tertiary phosphine ligand. This chemistry is dependent on the identity of the

  16. Solvent extraction of rare-earth metals with bis(2-ethylhexyl)phosphinic acid

    Microsoft Academic Search

    Yukio Nagaosa; Yao Binghua

    1997-01-01

    The extraction behavior of tervalent rare-earth metals (Ln) using a heptane solution containing bis(2-ethylhexyl)phosphinic\\u000a acid (PIA-8, HR) from 0.1?mol\\/dm3 sodium perchlorate media was studied. The pH0.5 values and separation factors obtained were compared among the metals. The stoichiometry of the extracted species and the\\u000a extraction constants for the present aqueous\\/heptane system were determined by slope analysis. It is demonstrated that

  17. Phosphine-mediated one-pot thiol-ene "click" approach to polymer-protein conjugates.

    PubMed

    Jones, Mathew W; Mantovani, Giuseppe; Ryan, Sinead M; Wang, Xuexuan; Brayden, David J; Haddleton, David M

    2009-09-21

    We employ water-soluble organic phosphines as key reagents in a one-pot synthetic protocol where a (poly)peptide disulfide bridge is first reduced followed by subsequent reaction of the two thiols in situ with poly(monomethoxy ethylene glycol)(meth)acrylates (p(mPEG)(M)A); we use salmon calcitonin (sCT) as a disulfide bridge-containing peptide, which contains a disulfide bridge-Cys1-Cys7-that can be reduced to give two sulfhydryl units available for thiol functionalisation; bioactivity is retained. PMID:19707643

  18. A Spectrophotometric Method for Quantitative Determination of Bromine Using Tris(2-carboxyethyl)phosphine

    NASA Astrophysics Data System (ADS)

    Han, Joan; Story, Troy; Han, Grace

    1999-07-01

    A simple spectrophotometric method for quantitative determination of bromine is described. The sample containing bromine is first incubated with an excess of tris(2-carboxyethyl)phosphine (TCEP). One molecule of TCEP is rapidly and irreversibly oxidized to TCEPO (TCEP oxide) by one molecule of bromine. The concentration of residual TCEP is then measured as 2-nitro-5-thiobenzoate produced by reaction with 5,5'-dithiobis(2-nitrobenzoic acid). This method has a lower detection limit and is more convenient than the standard procedure of bromine assay by reaction with potassium iodide followed by titration of the liberated iodine with thiosulfate.

  19. 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.

  20. Virtually Instantaneous, Room-temperature [11C]-Cyanation Using Biaryl Phosphine Pd(0) Complexes

    PubMed Central

    Lee, Hong Geun; Milner, Phillip J.; Placzek, Michael S.; Buchwald, Stephen L.; Hooker, Jacob M.

    2015-01-01

    A new radiosynthetic protocol for the preparation of [11C]aryl nitriles has been developed. This process is based on the direct reaction of in situ prepared L•Pd(Ar)X complexes (L=biaryl phosphine) with [11C]HCN. The strategy is operationally simple, exhibits a remarkably wide substrate scope with short reaction times, and demonstrates superior reactivity compared to previously reported systems. With this procedure, a variety of [11C]nitrile-containing pharmaceuticals were prepared with high radiochemical efficiency. PMID:25565277

  1. Accidental phosphine gas poisoning with fatal myocardial dysfunction in two families.

    PubMed

    Akhtar, Saleem; Rehman, Arshalooz; Bano, Surraya; Haque, Anwarul

    2015-05-01

    Aluminum phosphide is commonly used as a rodenticide and insecticide and is one of the most fatal poisons. The active ingredient is Phosphine gas which inhibits cytochrome oxidase and cellular oxygen utilization. The clinical symptoms are due to multiorgan involvement including cardiac toxicity which is the most common cause of mortality. Severity of clinical manifestations depends upon the amount of the gas to which a person is exposed. There is no specific antidote available. High index of suspicion and early aggressive treatment is the key to success. We report 2 cases of aluminum phosphide toxicity in 2 families due to incidental exposure after fumigation. PMID:26008669

  2. Virtually instantaneous, room-temperature [(11)C]-cyanation using biaryl phosphine Pd(0) complexes.

    PubMed

    Lee, Hong Geun; Milner, Phillip J; Placzek, Michael S; Buchwald, Stephen L; Hooker, Jacob M

    2015-01-21

    A new radiosynthetic protocol for the preparation of [(11)C]aryl nitriles has been developed. This process is based on the direct reaction of in situ prepared L·Pd(Ar)X complexes (L = biaryl phosphine) with [(11)C]HCN. The strategy is operationally simple, exhibits a remarkably wide substrate scope with short reaction times, and demonstrates superior reactivity compared to previously reported systems. With this procedure, a variety of [(11)C]nitrile-containing pharmaceuticals were prepared with high radiochemical efficiency. PMID:25565277

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

    PubMed

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

    2013-01-01

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

  4. Tertiary arsine-stabilised arsenium salts: syntheses and comparisons with phosphine analogues.

    PubMed

    Kilah, Nathan L; Weir, Michelle L; Wild, S Bruce

    2008-05-14

    The first tertiary arsine-stabilised arsenium salts, [(L)AsMePh]OTf (L = Ph3As, Me2PhAs, [2-(MeOCH2)C6H4]Ph2As, [2-(MeOCH2)C6H4]Me2As), have been prepared by chloride abstraction from chloromethylphenylarsine with trimethylsilyl triflate in the presence of the arsine. The complexes have been characterised by crystallography and 1H NMR spectroscopy. The chiral cations in the complexes have structures based on the trigonal pyramid in which the arsine is coordinated orthogonally to the prochiral, six-electron MePhAs+ ion that forms the base of the pyramid. The NMR data for the complexes in dichloromethane-d2 are consistent with rapid exchange of the arsine on the arsenium ion, even at 183 K. The corresponding phosphine-stabilised complexes are considerably more stable than their arsine counterparts in dichloromethane-d2 with the free energy of activation DeltaG = ca. 60 kJ mol(-1) being calculated for phosphine exchange in [(Me2PhP)AsMePh]OTf at 281 K; for [(Me2[2-(MeOCH2)C6H4]P)AsMePh]OTf in the same solvent, DeltaG = ca. 70 kJ mol(-1) at 323 K. PMID:18461204

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

    PubMed

    Komarnicka, Urszula K; Starosta, Rados?aw; Kyzio?, Agnieszka; Je?owska-Bojczuk, Ma?gorzata

    2015-07-01

    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 () or 2,2'-biquinoline () 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 complexes are characterised by strong inhibitory properties, while the 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. PMID:26085118

  6. 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.

  7. 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.

  8. Hydrogen fluoride adduct of an ambiphilic phosphine-borane: NMR characterization and theoretical analysis of the bonding situation.

    PubMed

    Moebs-Sanchez, Sylvie; Saffon, Nathalie; Bouhadir, Ghenwa; Maron, Laurent; Bourissou, Didier

    2010-05-14

    The HF adduct of the ambiphilic phosphine-borane [o-iPr(2)P(C(6)H(4))BMes(2)] has been spectroscopically characterized and the nature of the interaction between the ensuing hydrogenophosphonium and fluoroborate moieties has been analyzed computationally. PMID:20422099

  9. 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 ?-amino boronic esters were obtained through an achiral counteranion switch. PMID:25906191

  10. Enantioselective direct Mannich reactions of cyclic ?-ketoesters catalyzed by chiral phosphine via a novel dual-reagent catalysis.

    PubMed

    Lou, Yan-Peng; Zheng, Chang-Wu; Pan, Ren-Ming; Jin, Qiao-Wen; Zhao, Gang; Li, Zhong

    2015-02-01

    A combination of an amino acid derived chiral phosphine catalyst and methyl acrylate efficiently catalyzed the direct Mannich reaction of cyclic ?-ketoesters and N-Boc-aldimines. The dual-reagent catalysis was presumed to function through the formation of a zwitterion, which catalyzed the reaction with excellent stereocontrol via a hydrogen-bonding assisted chiral ion-pair pathway. PMID:25621822

  11. In situ Van der Pauw measurements of the Ni\\/YSZ anode during exposure to syngas with phosphine contaminant

    Microsoft Academic Search

    Oktay Demircan; Chunchuan Xu; John Zondlo; Harry O. Finklea

    2009-01-01

    Solid oxide fuel cells (SOFCs) represent an option to provide a bridging technology for energy conversion (coal syngas) as well as a long-term technology (hydrogen from biomass). Whether the fuel is coal syngas or hydrogen from biomass, the effect of impurities on the performance of the anode is a vital question. The anode resistivity during SOFC operation with phosphine-contaminated syngas

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

    PubMed

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

    2015-06-11

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

  13. Phosphine Adsorption on the In-Rich InP(001) Surface: Evidence of Surface Dative Bonds at Room Temperature

    E-print Network

    Hicks, Robert F.

    of phosphine on indium phosphide compound semiconductor surfaces is a key process during the chemical vapor process, though exothermic, involves a significant activation barrier of 23 kcal mol-1, suggestingSchofieldandco-workersusingatomicallyresolved STM images.7,8 In comparison, adsorption of arsine on silicon surfaces has received relatively minor

  14. On-line cleavage of disulfide bonds by soluble and immobilized tris-(2-carboxyethyl)phosphine using sequential injection analysis

    Microsoft Academic Search

    Paraskevas D. Tzanavaras; Constantina Mitani; Aristidis Anthemidis; Demetrius G. Themelis

    Reduction of disulfide bonds is – in many cases – a critical pretreatment step for the determination of thiols in real samples. This study reports the first systematic investigation of the potentials of the on-line reduction of disulfide bonds under flow conditions in a sequential injection setup. One of the most promising reducing agents, tris-(2-carboxyethyl)phosphine (TCEP) was selected for this

  15. A Comparison between the Sulfhydryl Reductants Tris(2-carboxyethyl)phosphine and Dithiothreitol for Use in Protein Biochemistry

    Microsoft Academic Search

    Elise Burmeister Getz; Ming Xiao; Tania Chakrabarty; Roger Cooke; Paul R. Selvin

    1999-01-01

    The newly introduced sulfhydryl reductant tris(2-carboxyethyl)phosphine (TCEP) is a potentially attractive alternative to commonly used dithiothreitol (DTT). We compare properties of DTT and TCEP important in protein biochemistry, using the motor enzyme myosin as an example protein. The reductants equally preserve myosin's enzymatic activity, which is sensitive to sulfhydryl oxidation. When labeling with extrinsic probes, DTT inhibits maleimide attachment to

  16. Phosphine and arsine decomposition in CVD reactors for InP and InGaAs growth

    NASA Astrophysics Data System (ADS)

    Harrous, M.; Chaput, L.; Bendraoui, A.; Cadoret, M.; Pariset, C.; Cadoret, R.

    1988-10-01

    A model of phosphine and arsine decomposition is developed that permits the taking into account of real partial pressure of hybrides in a CVD reactor for InP and InGaAs growth. It agrees with experimental results and explains the existence of two growth regimes of InP.

  17. Development of polymeric sensing films based on a tridentate bis(phosphinic amide)-phosphine oxide for detecting europium(III) in water.

    PubMed

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

    2012-06-14

    A novel europium(III) membrane luminescence sensor based on a tridentate bis(phosphinic amide)-phosphine oxide, PhPO(C(6)H(4)POPhN(CH(CH(3))(2))(2))(2) (1), is described. The new luminescent complex, [Eu(1)(2)]Cl(3)2, which is formed between europium(III) and ligand 1 and has a 1 : 2 stoichiometry, has been evaluated in solution. It has the excellent spectroscopic and chemical characteristics that make it appropriate for sensing film applications. All the parameters (polymer, plasticizer, ligand and ionic additive) that can affect the sensitivity and selectivity of the membrane sensor and instrumental conditions have been carefully optimized. The best sensing response (?(exc) = 229.04 nm, ?(em) = 616.02 nm) was observed for 33.4 : 65.1 : 1.5 (%, w/w) PVC : DOS : 1. The sensing film shows a good response time (10 min) and a very good selectivity toward europium(III) with respect to other lanthanides(III) ions, such as La, Sm, Tb and Yb. The newly-developed sensing film has a linear range from 1.6 × 10(-7) to 5.0 × 10(-6) mol L(-1) for Eu ions with a very low detection limit (4.8 × 10(-8) mol L(-1)) and good sensitivity (9.41 × 10(-7) a.u. mol(-1) L(-1)) to europium. Complexes of [Eu(1)(2)]Cl(3) (2) and [Eu(1)]Cl(3) (4) were isolated by mixing ligand 1 with Eu(Cl(3))·6H(2)O in acetonitrile at room temperature in ligand : metal molar ratios of 1 : 2 and 1 : 1, respectively. The 1 : 1 derivative is the product of thermodynamic control when a molar ratio of ligand to europium salt of 1 : 1 is used. The new compounds have been characterized in both the solid form (IR, MS-TOF, elemental analysis, TGA and X-ray diffraction) and in solution (multinuclear magnetic resonance). In both europium complexes, the ligand acts as a tridentate chelate. Thermogravimetric (TG) studies demonstrated that neither complex 2 or 4 possess any water molecules directly bound to the lanthanide metal, which corroborates the X-ray structure. The investigation of the solution behaviour of the Y(III) complexes with pulsed gradient spin-echo (PGSE) NMR diffusion measurements showed that average structures with 1 : 1 and 1 : 2 stoichiometries are retained in acetonitrile solutions. PMID:22535314

  18. 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.

  19. Cationic gold clusters ligated with differently substituted phosphines: effect of substitution on ligand reactivity and binding.

    PubMed

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

    2015-05-27

    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 reactions between pre-formed triphenylphosphine ligated (PPh3) gold clusters and monodentate Me- and Cy-substituted phosphine 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 reaction decreases with an increasing number of Me or Cy groups in the substituted phosphine ligands. CID experiments performed for a series of mixed-ligand gold clusters indicate that loss of a neutral Me-substituted ligand is preferred over loss of a neutral PPh3 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) on each cluster. This study provides the first experimental determination of the relative binding energies of ligated gold clusters containing differently substituted monophosphine ligands, which are important to controlling their synthesis and reactivity in solution. The results also indicate that ligand substitution is an important parameter that must be considered in theoretical modeling of these complex systems. PMID:25971528

  20. Correction: Facile synthesis of phosphine free ultra-small PbSe nanocrystals and their light harvesting studies in ETA solar cells.

    PubMed

    Akhtar, Javeed; Banski, Mateusz; Malik, Mohammad Azad; Revaprasadu, Neerish; Podhorodecki, Artur; Misiewicz, Jan

    2015-07-01

    Correction for 'Facile synthesis of phosphine free ultra-small PbSe nanocrystals and their light harvesting studies in ETA solar cells' by Javeed Akhtar, et al., Dalton Trans., 2014, 43, 16424-16430. PMID:26101182

  1. SH···N and SH···P blue-shifting H-bonds and N···P interactions in complexes pairing HSN with amines and phosphines.

    PubMed

    Solimannejad, Mohammad; Gharabaghi, Masumeh; Scheiner, Steve

    2011-01-14

    Quantum calculations at the MP2/aug-cc-pVDZ level examine complexes pairing HSN with aliphatic amines and phosphines. Complexes are cyclic and contain two attractive interactions. The first is a SH···N/P H-bond in which the S-H covalent bond contracts and shifts its stretching frequency to the blue, more so for amines than for phosphines. The second interaction is different for the amines and phosphines. The amines engage in a NH···N H-bond comparable in strength to the aforementioned SH···N interaction. In contrast, the second interaction in the phosphine complexes is a direct N···P attraction without an intervening H. This interaction is due in part to opposite partial charges on the N and P atoms, as well as covalent forces generated by charge transfer effects. PMID:21241104

  2. 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. (Northwestern Univ., Evanston, IL (USA))

    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.

  3. Efficient bulky phosphines for the selective telomerization of 1,3-butadiene with methanol.

    PubMed

    Tschan, Mathieu J-L; García-Suárez, Eduardo J; Freixa, Zoraida; Launay, Hélène; Hagen, Henk; Benet-Buchholz, Jordi; van Leeuwen, Piet W N M

    2010-05-12

    A series of bulky phosphines containing substituted biphenyl, 2-methylnaphthyl, or 2,7-di-tert-butyl-9,9-dimethylxanthene moiety were prepared. They were used in the preparation of new monophosphine-palladium(0)-dvds complexes, which were employed as catalysts for the selective telomerization of 1,3-butadiene with methanol to obtain 1-methoxyocta-2,7-diene (1-MOD), the key intermediate in the Dow 1-octene process. Several ligands showed improved selectivity and yield compared to that of the benchmark ligand PPh(3). Especially 2,7-di-tert-butyl-9,9-dimethylxanthen-4-yl-diphenylphosphine (4, "mono-xantphos") stands out as an excellent ligand in terms of yield, selectivity, and stability. PMID:20405840

  4. 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.

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

    PubMed

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

    2002-05-22

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

  6. 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.

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

    PubMed

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

    2015-05-01

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

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

    PubMed

    Notni, Johannes; Šime?ek, 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

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

    SciTech Connect

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

    2007-01-01

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

  10. Response of mixed-age cultures of phosphine-resistant and susceptible strains of lesser grain borer, Rhyzopertha dominica, to phosphine at a range of concentrations and exposure periods

    Microsoft Academic Search

    Patrick J. Collins; Gregory J. Daglish; Hervoika Pavic; Rosemary A. Kopittke

    2005-01-01

    Mixed-age cultures, containing all life stages, of a highly resistant strain (Strong-R) of lesser grain borer, Rhyzopertha dominica (F.), were exposed to a series of fixed concentrations of phosphine at a range of exposure periods at 25°C. A susceptible strain and a less-resistant strain (Weak-R) were also tested. The aim was to characterise the resistant strain and determine if it

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

    PubMed Central

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

    2010-01-01

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

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

    PubMed

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

    2010-01-01

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

  13. Influence of extractant structure on extraction of nitric acid and americium(III) with diaryl (dialkyl)[diethylcarbamoylmethyl]phosphine oxides

    Microsoft Academic Search

    M. K. Chmutova; L. A. Ivanova; N. E. Kochetkova

    1995-01-01

    A study has been made of nitric acid and americium(III) extraction with dichlorethane solutions of dialkl-(diaryl)[diethylcarbamoylmethyl]phosphine oxides containing various substituents (alkyl, aryl, alkoxyl, and mixed-ligand) at the phosphorus atom. Nitric acid is extracted as complexes containing one, two, or three acid molecules per molecule of the reagent. The effective constants of the nitric acid extraction by all the reagents ({bar

  14. Cadmium extraction from hydrochloric acid solutions using Amberlite XAD-7 impregnated with Cyanex 921 (tri-octyl phosphine oxide)

    Microsoft Academic Search

    R. Navarro; I. Saucedo; A. Núñez; M. Ávila; E. Guibal

    2008-01-01

    Cyanex® 921 (tri-octyl phosphine oxide, TOPO) was successfully used for the impregnation of Amberlite® XAD-7 to prepare an extractant-impregnated resin (EIR). This EIR was used for the recovery of cadmium from concentrated HCl solutions. Though the maximum loading of Cyanex 921 in the EIR can reach 580mgg?1, a lower concentration (below 400mgg?1) enabled better use of the extractant. The Langmuir

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

    PubMed Central

    Tin, Sergey; Fanjul, Tamara

    2015-01-01

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

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

    Microsoft Academic Search

    M. L. P Reddy; J. R Bosco Bharathi; Smitha Peter; T. R Ramamohan

    1999-01-01

    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 MX3.3HX with Cyanex 301 alone. In the presence of Cyanex 923, La(III) and Nd(III) are found to be extracted as

  17. 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. PMID:25826251

  18. Design, synthesis, and application of a chiral sulfinamide phosphine catalyst for the enantioselective intramolecular rauhut-currier reaction.

    PubMed

    Su, Xiao; Zhou, Wei; Li, Yangyan; Zhang, Junliang

    2015-06-01

    A novel class of chiral sulfinamide phosphine catalysts (Xiao-Phos) are reported, which can be easily prepared from inexpensive commercially available starting materials. The Xiao-Phos catalysts showed good performance in enantioselective intramolecular Rauhut-Currier reactions, generating ?-methylene-?-butyrolactones in high yields with up to 99?% ee under mild conditions. Moreover, kinetic resolution and parallel kinetic resolution were also observed with the use of two different substituted racemic precursors. PMID:25907710

  19. New Water-Soluble Phosphines as Reductants of Peptide and Protein Disulfide Bonds:  Reactivity and Membrane Permeability †

    Microsoft Academic Search

    Daniel J. Cline; Sarah E. Redding; Stephen G. Brohawn; James N. Psathas; Joel P. Schneider; Colin Thorpe

    2004-01-01

    Tris(2-carboxyethyl)phosphine (TCEP) is a widely used substitute for dithiothreitol (DTT) in the reduction of disulfide bonds in biochemical systems. Although TCEP has been recently shown to be a substrate of the flavin-dependent sulfhydryl oxidases, there is little quantitative information concerning the rate by which TCEP reduces other peptidic disulfide bonds. In this study, mono-, di-, and trimethyl ester analogues of

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

    Microsoft Academic Search

    René Kizek; Jan Vacek; Libuše Trnková; František Jelen

    2004-01-01

    The stabilization of the reduction state of proteins and peptides is very important for the monitoring of protein–protein, protein–DNA and protein–xenobiotic interactions. The reductive state of protein or peptide is characterized by the reactive sulfhydryl group. Glutathione in the reduced (GSH) and oxidized (GSSG) forms was studied by cyclic voltammetry. Tris(2-carboxyethyl)phosphine (TCEP) as the disulfide bond reductant and\\/or hydrogen peroxide

  1. Tris(2-carboxyethyl)phosphine stabilization of RNA: comparison with dithiothreitol for use with nucleic acid and thiophosphoryl chemistryq

    Microsoft Academic Search

    Steven S. Rhee; Donald H. Burke

    We assessed the utility of the sulfhydryl reductant Tris(2-carboxyethyl)phosphine (TCEP) for both nucleic acid and thiophos- phate chemistry, including its effects on organomercurial gel electrophoresis, RNA catalysis, RNA backbone stability, and the intrinsic stability of TCEP. The sulfhydryls of dithiothreitol (DTT) compete with thiophosphates for binding to the mercury within ((N-acryloylamino)phenyl) mercuric chloride (APM) polyacrylamide gels, whereas millimolar concentrations of

  2. Quantitative analysis of tris(2-carboxyethyl)phosphine by anion-exchange chromatography and evaporative light-scattering detection

    Microsoft Academic Search

    Zhijun Tan; Peter M. Ihnat; Vikram S. Nayak; Reb J. Russell

    Tris(2-carboxyethyl)phosphine (TCEP) belongs to the trialkylphosphine class of reducing agents that are widely used in research and industry. In this paper, we discuss a sensitive high-performance liquid chromatography (HPLC) method equipped with an evaporative light scattering detector (ELSD) for the determination of TCEP in pharmaceutical samples containing therapeutic protein and stabilizing additives. TCEP was first completely oxidized with hydrogen peroxide

  3. Tris(2-carboxyethyl)phosphine stabilization of RNA: comparison with dithiothreitol for use with nucleic acid and thiophosphoryl chemistry

    Microsoft Academic Search

    Steven S Rhee; Donald H Burke

    2004-01-01

    We assessed the utility of the sulfhydryl reductant Tris(2-carboxyethyl)phosphine (TCEP) for both nucleic acid and thiophosphate chemistry, including its effects on organomercurial gel electrophoresis, RNA catalysis, RNA backbone stability, and the intrinsic stability of TCEP. The sulfhydryls of dithiothreitol (DTT) compete with thiophosphates for binding to the mercury within [(N-acryloylamino)phenyl] mercuric chloride (APM) polyacrylamide gels, whereas millimolar concentrations of TCEP

  4. The rph2 Gene Is Responsible for High Level Resistance to Phosphine in Independent Field Strains of Rhyzopertha dominica

    PubMed Central

    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 (SRQLD), New South Wales (SRNSW) and South Australia (SRSA), 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, SR2QLD, also from Queensland. The previously described rph2 gene, which interacts synergistically with rph1 gene, confers strong resistance on SRQLD and SRNSW. We now provide strong circumstantial evidence that weak alleles of rph2, together with rph1, contribute to the strong resistance phenotypes of SRSA and SR2QLD. 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. PMID:22461899

  5. 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. PMID:22461899

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

    SciTech Connect

    Edelbach, B.L.; Vicic, D.A.; Lachicotte, R.J.; Jones, W.D. [Univ. of Rochester, NY (United States). Dept. of Chemistry] [Univ. of Rochester, NY (United States). Dept. of Chemistry

    1998-10-26

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

  7. Synthesis and Mossbauer spectroscopic studies of chemically oxidized ferrocenyl(phenyl)phosphines.

    PubMed

    Durfey, D A; Kirss, R U; Frommen, C; Feighery, W

    The electrochemical potentials of Fc3-xPPhx, (1-3, x = 0-2) and (FcPPh)n (4) indicate that iodine should oxidize ferrocenyl(phenyl)phosphines. The molar conductivity of solutions of 1-3 increases sharply when the solutions are titrated with iodine, leveling off after the addition of > 2 equiv of oxidant, consistent with formation of 1:1 electrolytes. Diamagnetic salts 6-9 are observed upon addition of a benzene solution of iodine to a benzene solution of 1-4 at ambient temperature in ratios of I2/metallocene ranging from 1:1 to 2:1. Well-resolved 1H and 31P NMR spectra are obtained for 6-8. Absorptions assigned to the I3- anion dominate the UV-vis spectrum of 6-8, whereas characteristic absorptions for [Fc][I3] are absent. Mossbauer spectra of 7-9 reveal isomer shifts consistent with low-spin iron(II) in ferrocene derivatives rather than those in ferricenium ions. Small amounts of low-spin FeIII appear to be present in 6. Taken together, the results suggest that 6-9 are iodophosphonium salts and not ferricenium salts. Diferrocenyl(phenyl)phosphine oxide (5) reacts with iodine to produce a diamagnetic, dark solid 10. Low-spin FeII is observed at 77 and 293 K in the Mossbauer spectra of 10 with no evidence for oxidation of FeII to FeIII. Compound 10 is proposed to be a neutral complex between 5 and I2. Reactions between 5 and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) yield [Fc2P(=O)][DDQ]2 (11). Mossbauer spectroscopy of 11 indicates the presence of a mixture of low-spin FeII and low-spin FeIII at 77 K, suggesting that some electron transfer occurs from 5 to DDQ. The fraction of low-spin FeIII increases at room temperature. PMID:11196808

  8. Phosphine in the marine atmosphere along a hemispheric course from China to Antarctica

    NASA Astrophysics Data System (ADS)

    Zhu, Renbin; Glindemann, Dietmar; Kong, Deming; Sun, Liguang; Geng, Jinju; Wang, Xiaorong

    The gas phosphine (PH 3) is a part of an atmospheric link of the phosphorus cycle on earth. Previous research reported the terrestrial lower tropospheric PH 3 at night in the 1 ng m -3 range in remote areas, with the peak of 100 ng m -3 in populated areas, and at daytime even lower concentrations in the pg m -3 range. The data of the global marine atmospheric PH 3 are still very sparse. This study presents surprisingly high concentrations of PH 3 in the order of 0.1-1 ?g m -3 in many of 32 samples of the marine atmosphere in the latitudinal range from 30°N to 65°S (the cruise of research ship Xuelong from Shanghai Harbor, China, to Antarctica). The highest concentrations were measured near coastal areas of Eastern Asia and Western Australia. A significant correlation exists between marine atmospheric PH 3 concentration and air temperature at 22:00 (local time). PH 3 concentrations at different latitudes strongly decline with daylight intensity according to a logarithmic relationship. These surprisingly high concentrations of the readily oxidizable PH 3 in the air indicate hitherto unknown but important PH 3 emission sources in marine environment. More work is necessary to evaluate the sources of atmospheric PH 3 from marine biosphere.

  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. Photochemical reaction of phosphine hydride complexes of molybdenum and tungsten with molecular nitrogen

    SciTech Connect

    Pivovarov, A.P.; Gak, Y.V.; Doronina, T.N.; Makhaev, V.D.; Borisov, A.P.; Borod'ka, Y.G.

    1981-01-01

    Nitrogen complexes of molybdenum and tungsten react (rapidly when illuminated but slowly in the dark) with halogen-containing organic compounds to form products containing N-C bonds. Phosphine hydride complexes of type MH/sub 4/L/sub 4/ (M = Mo, W; L = PMePh/sub 2/, PEtPh/sub 2/, PEt/sub 2/Ph, PPrPh/sub 2/, PBuPh/sub 2/) take part in a photochemical reaction with N/sub 2/, giving nitrogen-containing products capable of reduction to hydrazine. We have investigated the composition of the nitrogen-containing photoproducts and the kinetic characteristics of their formation for the case of the complexes MoH/sub 4/(dppe)/sub 2/, WH/sub 4/(dppe)/sub 2/, MoH/sub 4/(PMePh/sub 2/)/sub 4/, WH/sub 4/(PMePh/sub 2/)/sub 4/, where dppe = 1,2-bis(diphenylphosphino)ethane.

  11. Protein binding studies of technetium-99m-labeled phosphine and isocyanide cationic complexes

    SciTech Connect

    Zanelli, G.D.; Cook, N.; Lahiri, A.; Ellison, D.; Webbon, P.; Woolley, G.

    1988-01-01

    Most /sup 99m/Tc/phosphine/isocyanide complexes synthesized to date show preferential uptake by the myocardium of many animal species but not in man. A new complex has been synthesized, (/sup 99m/Tc(DEPE)2(CNR)2), +(DEPIC), where R = t - butyl isocyanide, which in three animal species images the myocardium very well, but in humans it remains primarily in the blood pool. One reason for the difference in the behavior of these complexes in different species could be the characteristics of their binding to plasma proteins. The protein binding characteristics of DEPIC and two other well-known complexes have therefore been studied. Whereas the other complexes bind nonspecifically to many proteins both in animal and human plasma, DEPIC binds almost exclusively to prealbumin in humans but nonspecifically to other proteins in the rabbit. The binding sites in human plasma appear to be those normally occupied by thyroxine on the prealbumin tetramer and these can be blocked by sodium salicylate.

  12. 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.

  13. Matrix bound phosphine in sediments of the yellow sea and its coastal areas

    NASA Astrophysics Data System (ADS)

    Li, Jian-Bing; Zhang, Gui-Ling; Zhang, Jing; Liu, Su-Mei; Ren, Jing-Ling

    2010-04-01

    Matrix bound phosphine (MBP), a kind of chemically reduced phosphorus, has received limited attention in prevailing modeling of the phosphorus biogeochemical cycle. MBP has been found to occur in marine sediments. MBP in the sediments of the Yellow Sea and its coastal areas was measured by gas chromatography from 2004 to 2007. MBP levels in surface sediments were 0.19-38.24 ng kg -1 in the shelf of the Yellow Sea, 0.34-17.15 ng kg -1 in the Jiaozhou Bay, 2.11-71.79 ng kg -1 in the Sanggou Bay and 0.28-319.32 ng kg -1 in the rivers around the Jiaozhou Bay. High levels of MBP occurred in the northern and middle areas of the Yellow Sea. Obvious seasonal variation of MBP was observed in surface sediments of the Sanggou Bay, with the highest MBP level occurring in summer and the lowest in winter. MBP in surface sediments of the inner Jiaozhou Bay was higher than those in the outer region. MBP levels increased with depth in the top 5-10 cm sediments of the Jiaozhou Bay and on the intertidal flats. Environmental factors such as type of sediments, temperature, organic matter and human activity were found to affect the concentrations and distribution of MBP in marine sediments.

  14. Wideband dye-sensitized solar cells employing a phosphine-coordinated ruthenium sensitizer

    NASA Astrophysics Data System (ADS)

    Kinoshita, Takumi; Dy, Joanne Ting; Uchida, Satoshi; Kubo, Takaya; Segawa, Hiroshi

    2013-07-01

    Low-cost renewable energies are necessary for the realization of a low-carbon society. Organic photovoltaics such as organic thin-film solar cells and dye-sensitized solar cells (DSSCs) are promising candidates for realizing low-cost solar cells. However, device efficiencies are still considerably lower than those of traditional inorganic solar cells. To improve organic photovoltaic performance, approaches are needed to extend the absorption of organic compounds to longer wavelengths. Here, we report efficient DSSCs that exploit near-infrared, spin-forbidden singlet-to-triplet direct transitions in a phosphine-coordinated Ru(II) sensitizer, DX1. A DSSC using DX1 generated a photocurrent density of 26.8 mA cm-2, the highest value for an organic photovoltaic reported to date. A tandem-type DSSC employing both DX1 and the traditional sensitizer N719 is shown to have a power conversion efficiency of >12% under 35.5 mW cm-2 simulated sunlight.

  15. Homogeneous, single-phase hydroformylation of olefins using ionic phosphines and novel catalyst/product separation

    SciTech Connect

    Abatjoglou, A.G.; Peterson, R.R.; Bryant, D.R. [Union Carbide Technical Center, South Charleston, WV (United States)

    1995-12-01

    A high efficiency low pressure hydroformylation process for higher molecular weight olefins has been developed using rhodium/ionic phosphine catalyst. Catalyst solubilization in the non-polar reactants and products is achieved using specialized solubilizing agents, such as N-methyl pyrrolidone (NMP), yielding single-phase systems. Separation of catalyst from product is induced by the addition of small amounts of water outside the hydroformylation reactor. Under the two-phase conditions, most of the catalyst components are found in the polar NMP/water phase, and the products (aldehydes, olefins, reaction byproducts) in a separate, non-polar, phase. The catalyst phase is recycled to the reactors after thorough drying to ensure a single homogeneous phase at reaction conditions. Traces of catalyst and solubilizing agent are effectively recovered from the product and recycled. A major advantage of this process, over water-based two-phase systems, is the high catalytic reactivities and concomitant high olefin efficiencies (>90%) which are achieved with olefins of low, water solubility.

  16. New phosphine-diamine and phosphine-amino-alcohol tridentate ligands for ruthenium catalysed enantioselective hydrogenation of ketones and a concise lactone synthesis enabled by asymmetric reduction of cyano-ketones.

    PubMed

    Fuentes, José A; Phillips, Scott D; Clarke, Matthew L

    2012-01-01

    Enantioselective hydrogenation of ketones is a key reaction in organic chemistry. In the past, we have attempted to deal with some unsolved challenges in this arena by introducing chiral tridentate phosphine-diamine/Ru catalysts. New catalysts and new applications are presented here, including the synthesis of phosphine-amino-alcohol P,N,OH ligands derived from (R,S)-1-amino-2-indanol, (S,S)-1-amino-2-indanol and a new chiral P,N,N ligand derived from (R,R)-1,2-diphenylethylenediamine. Ruthenium pre-catalysts of type [RuCl2(L)(DMSO)] were isolated and then examined in the hydrogenation of ketones. While the new P,N,OH ligand based catalysts are poor, the new P,N,N system gives up to 98% e.e. on substrates that do not react at all with most catalysts. A preliminary attempt at realising a new delta lactone synthesis by organocatalytic Michael addition between acetophenone and acrylonitrile, followed by asymmetric hydrogenation of the nitrile functionalised ketone is challenging in part due to the Michael addition chemistry, but also since Noyori pressure hydrogenation catalysts gave massively reduced reactivity relative to their performance for other acetophenone derivatives. The Ru phosphine-diamine system allowed quantitative conversion and around 50% e.e. The product can be converted into a delta lactone by treatment with KOH with complete retention of enantiomeric excess. This approach potentially offers access to this class of chiral molecules in three steps from the extremely cheap building blocks acrylonitrile and methyl-ketones; we encourage researchers to improve on our efforts in this potentially useful but currently flawed process. PMID:23216944

  17. New phosphine-diamine and phosphine-amino-alcohol tridentate ligands for ruthenium catalysed enantioselective hydrogenation of ketones and a concise lactone synthesis enabled by asymmetric reduction of cyano-ketones

    PubMed Central

    2012-01-01

    Enantioselective hydrogenation of ketones is a key reaction in organic chemistry. In the past, we have attempted to deal with some unsolved challenges in this arena by introducing chiral tridentate phosphine-diamine/Ru catalysts. New catalysts and new applications are presented here, including the synthesis of phosphine-amino-alcohol P,N,OH ligands derived from (R,S)-1-amino-2-indanol, (S,S)-1-amino-2-indanol and a new chiral P,N,N ligand derived from (R,R)-1,2-diphenylethylenediamine. Ruthenium pre-catalysts of type [RuCl2(L)(DMSO)] were isolated and then examined in the hydrogenation of ketones. While the new P,N,OH ligand based catalysts are poor, the new P,N,N system gives up to 98% e.e. on substrates that do not react at all with most catalysts. A preliminary attempt at realising a new delta lactone synthesis by organocatalytic Michael addition between acetophenone and acrylonitrile, followed by asymmetric hydrogenation of the nitrile functionalised ketone is challenging in part due to the Michael addition chemistry, but also since Noyori pressure hydrogenation catalysts gave massively reduced reactivity relative to their performance for other acetophenone derivatives. The Ru phosphine-diamine system allowed quantitative conversion and around 50% e.e. The product can be converted into a delta lactone by treatment with KOH with complete retention of enantiomeric excess. This approach potentially offers access to this class of chiral molecules in three steps from the extremely cheap building blocks acrylonitrile and methyl-ketones; we encourage researchers to improve on our efforts in this potentially useful but currently flawed process. PMID:23216944

  18. Improvement of the photochemical reactivity of (Cu(dmp)P2) (dmp = 2,9-dimethyl-1,10-phenanthroline; P = tertiary phosphine) by substituting PPh3 with larger phosphines: application to photoreduction of methylviologen

    SciTech Connect

    Sakaki, S.; Koga, G.; Hinokuma, S.; Hashimoto, S.; Ohkubo, K.

    1987-06-03

    Cu(I) complexes containing heteroaromatic ligands such as 2,2'-bipyridine (bpy) or 1,10-phenanthroline exhibit a metal-to-ligand charge-transfer (MLCT) band in the visible to near-ultraviolet spectral region and have a triplet MLCT state as the lowest energy excited state like (Ru(bpy)3)S which has been applied extensively to the photochemical reduction of water to hydrogen gas. Nevertheless, application of those Cu(I) complexes to the photochemical reduction of water has not been carried out, excepting only one report of Sauvage et al. Recently, they reported that Cu(I) complexes containing a heteroaromatic ligand, (Cu(NN)(PPh3)2) (NN = 2,9-dimethyl-1,10-phenanthroline (dmp) or 4,4',6,6'-tetramethyl-2,2'-bipyridine), found application as a sensitizer in photocatalytic reduction of methylviologen (MVS ) upon near-UV-light irradiation. Unfortunately, however, the quantum yield for MVS reduction (phi/sub MV /) is lower than that of (Ru(bpy)3)S . In this work, they have succeeded in improving the photoreducing activity of (Cu(dmp)(PPh3)S) by using such bulky and/or donating tertiary phosphines as cyclohexyldiphenylphosphine, PCyPh2, and tris(p-methoxyphenyl)phosphine, P(p-C6H4OMe)3, instead of PPh3. Another emphasis presented here lies in investigating the phosphine ligand effect on the photoreactivity of Cu(I) complexes, because such investigation has not been carried out yet to their knowledge.

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

    PubMed

    Reed, C

    2001-02-01

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

  20. Lithium-selective phosphine oxide-based ditopic receptors show enhanced halide binding upon alkali metal ion coordination†

    PubMed Central

    Gavette, Jesse V.; Lara, Juven; Reling, Linda L.; Haley, Michael M.; Johnson, Darren W.

    2012-01-01

    Previous work on a ditopic receptor based on a tripodal phosphine oxide core demonstrated preferential enhancement of bromide binding over chloride or iodide in the presence of lithium cation. Current studies on an elongated receptor provide evidence that preferential bromide binding enhancement in the presence of lithium cation is common to this receptor class in general, and that lengthening of the receptor results in an overall increase in halide association. Furthermore, the extended receptor shows a strong preference for Li+ binding in solution. PMID:23505609

  1. Extraction of uranyl nitrate with a binary extractant based on di(2,4,4-trimethylpentyl)phosphinic acid

    Microsoft Academic Search

    N. S. Egorova; V. V. Belova; A. A. Voshkin; A. I. Khol’kin; A. K. Pyartman; V. A. Keskinov

    2008-01-01

    The extraction of uranyl nitrate with methyltrioctylammomium di(2,4,4-trimethylpentyl)phosphinate is compared to uranyl nitrate\\u000a extraction with constituent cation-and anion-exchange extracting agents at various compositions of aqueous and organic phases.\\u000a In UO2(NO3)2 extraction with quaternary ammonium nitrate and dialkylphosphinic acid solutions in toluene, the compounds (R4N)2UO2(NO3)4 and UO2A2, respectively, are formed in the organic phase. The binary extraction of uranyl nitrate is

  2. Clay-reinforced semi-aromatic polyether-amide nanocomposites containing phosphine oxide moieties: synthesis and characterization

    Microsoft Academic Search

    Meisam Shabanian; Khalil Faghihi; Fatemeh Shabani

    Semi-aromatic flame retardant polyether-amide\\/organoclay nanocomposites were synthesis through solution blending technique.\\u000a Surface modification of the montmorillonite clay was performed with 1,4-bis[4,4?-amino phenoxy]butane for ample compatibilization\\u000a with the polyamide matrix. The polymer chains were produced from the poly condensation reaction of bis(3-amino phenyl)phenyl\\u000a phosphine oxide (4) with 1,4-(4-carboxy phenoxy)butane (3). The effect of clay dispersion and the interaction between clay\\u000a and

  3. Multifunctional phosphine stabilized gold nanoparticles: an active catalytic system for three-component coupling reaction.

    PubMed

    Borah, Bibek Jyoti; Borah, Subrat Jyoti; Dutta, Dipak Kumar

    2013-07-01

    Multifunctional phosphine based ligands, 1,1,1-tris(diphenylphosphinomethyl)ethane [CH3C(CH2 PPh2)3][P3] and 1,1,1-tris(diphenylphosphinomethyl)ethane trisulphide [CH3C(CH2P(S)Ph2)3][P3S3] have been introduced to stabilize Au(o)-nanoparticles having small core diameter and narrow size distribution. The Au(o)-nanoparticles were synthesized by the reduction of HAuCl4 precursor with NaBH4 in the presence of ligand P3 or P3S3 using two phases, one pot reaction at room temperature. The Au(o)-nanoparticles exhibit face centered cubic (fcc) lattice having different crystalline shape i.e., single crystallite stabilized by P3 while P3S3 forms decahedral shapes. Surface plasmon bands at -520 nm and TEM study indicate particle size below 2 and 4 nm for Au(o)-nanoparticles stabilized by P3 and P3S3 respectively, which are attributable to the stronger interaction of Au(o) (Soft) with P (Soft) than Au(o) (Soft) with S (less Softer than P). Au(o)-nanoparticles stabilized by P3S3 shows higher thermal stability than that of P3. The synthesized Au(o)-nanoparticles serve as an efficient catalyst for one-pot, three-component (A3) coupling of an aldehyde, an amine and an alkyne via C-H alkyne-activation to synthesize propargylamines (85-96%) without any additives and precaution to exclude air. PMID:23901533

  4. Different Coordination Modes of a Tripod Phosphine in Gold(I) and Silver(I) Complexes

    PubMed Central

    Sevillano, P.; Habtemariam, A.; Parsons, S.; Sadler, P. J.

    1999-01-01

    The following gold(I) and silver(I) complexes of the tritertiary phosphine 1,1,1- tris(diphenylphosphinomethyl)ethane, tripod , have been synthesised: Au3(tripod)X3 [X = Cl(1), Br(2), I(3)]; [Au3(tripod)2Cl2]Cl (4); Au(tripod)X [X = Br(5), I(6)]; Ag3(tripod) (NO3)4 (7), Ag(tripod)NO3 (8). They were characterized by X-ray diffraction (complexes 2, 3 and 4), 31P NMR spectroscopy, electrospray and FAB mass spectrometry and infrared spectroscopy. Complexes 2 and 3 show a linear coordination geometry for Au(I), with relatively short Au-P bond distances. Complex 3 has a Au•••Au intramolecular distance of 3.326 A ° , while complex 2 had a short Au•••Au intermolecular interaction of 3.048 A ° . Complexes 4-6 were found by 31P NMR spectroscopy studies to contain a mixture of species in solution, one of which crystallised as [Au3(tripod|)2Cl2]Cl which was shown by X-ray diffraction to contain both tetrahedral and linear Au(I), the first example of a Au(I) complex containing such a mixture of geometries. The reaction of [Au3 (tripod)Cl3] (1) with tripod led successfully to the formation of [Au3(tripod|)2Cl2]+ and [Au3(tripod)2Cl3]+ and [Au3(tripod|)3Cl]2+. The silver(I) complexes, 7 and 8 appear to contain linear and tetrahedral Ag(I), respectively. PMID:18475895

  5. Photophysical properties of Ru(II) bipyridyl complexes containing hemilabile phosphine-ether ligands.

    PubMed

    Angell, Sarah E; Zhang, Yan; Rogers, Cerrie W; Wolf, Michael O; Jones, Wayne E

    2005-10-17

    Emission and absorbance spectra, along with low-temperature excited-state lifetimes, were obtained for the hemilabile complexes, [Ru(bpy)2L](PF6)2 [L = (2-methoxyphenyl)diphenylphosphine (RuPOMe) (1) and (2-ethoxyphenyl)diphenylphosphine (RuPOEt) (2)] in solid 4:1 ethanol/methanol solution. Spectral data were evaluated with ground-state reduction potentials using Lever parameters. Lifetime data for these complexes were collected from 77 to 160 K, and the rate constant for the combined radiative and nonradiative decay process, k, the thermally activated process prefactor, k'(0), the rate constant for the MLCT --> d-d transition, k', and the activation energy, DeltaE', were calculated from a plot of ln(1/tau) versus 1/T for both (1) and (2). The low-temperature luminescence lifetimes of (1) were observed to decrease with increases in water concentration. The photophysical and kinetic data of (1) and (2) are compared to literature data for [Ru(bpy)3](PF6)2. The emission maxima of (1) and (2) are blue-shifted relative to [Ru(bpy)3](PF6)2 due to the presence of the strong-field phosphine ligand, which enhances pi back-bonding to the bipyridyl ligands. The thermal activation energy, DeltaE', is significantly larger for [Ru(bpy)3](PF6)2 than for (1) and (2) resulting in a faster MLCT --> d-d transition for (1) and (2). These results are discussed in the context of radiationless decay through thermally activated ligand-field states on the metal complex. PMID:16212363

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

    PubMed

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

    2015-08-01

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

  7. Solution and solid-state structures of phosphine adducts of monomeric zinc bisphenoxide complexes. Importance of these derivatives in CO2/epoxide copolymerization processes.

    PubMed

    Darensbourg, D J; Zimmer, M S; Rainey, P; Larkins, D L

    2000-04-01

    Phosphine derivatives of the monomeric zinc phenoxide complexes, (phenoxide)2ZnLn, where phenoxide equals 2,6-di-tert-butylphenoxide, 2,4,6-tri-tert-butylphenoxide, and 2,6-diphenylphenoxide and n = 1 or 2, have been synthesized from the reaction of Zn[N(SiMe3)2]2 and the corresponding phenol followed by the addition of phosphine. The complexes have been characterized in solution by 31P NMR spectroscopy and in selected instances in the solid-state by X-ray crystallography. The small, basic phosphine, PMe3, provided the only case of an isolated complex possessing two phosphine ligands (i.e., n = 2). For all other larger phosphines only the monophosphine adducts were obtained. Furthermore, only fairly basic phosphines were found to bind to zinc, e.g., whereas PPh3 (pKa = 2.73) was ineffective, PPh2Me (pKa = 4.57) did form a strong bond to zinc. The solid-state structures of the monophosphine adducts consist of a near-trigonal planar geometry about the zinc center, where the average P-Zn-O angles are larger than the O-Zn-O angles. On the other hand, the bisphosphine adduct, Zn(O-2,4,6-tBu3C6H2)(2).2PMe3, is a distorted tetrahedral structure with O-Zn-O and P-Zn-P bond angles of 108.8(2) degrees and 107.1(9) degrees, respectively. Competitive phosphine binding studies monitored by 31P NMR spectroscopy provided a relative binding order of PPh3 approximately PtBu3 < PPh2Me < PCy3 < PMe2Ph < PnBu3 < PEt3 < PMe3. Hence, the relative binding of basic phosphine ligands at these congested zinc sites is largely determined by their steric requirements. All phosphine adducts, with the exception of PMe2Ph and PMe3, were found to undergo slow self-exchange (< 600 s-1) with free phosphine by 31P NMR spectroscopy. However, the two small phosphines, PMe2Ph (cone angle = 122 degrees) and PMe3 (cone angle = 118 degrees), were shown to undergo rapid exchange presumably via an associative mechanism. Although there was no kinetic preferences for PCy3 binding to cadmium vs zinc, cadmium was thermodynamically favored by about a factor of 2.5. The addition of up to 3 equiv of PCy3 to the Zn(O-2,6-tBu2C6H3)2 or Zn(O-2,4,6-tBu3C6H2)2 derivatives did not significantly alter the reactivity of these catalysts for the copolymerization of cyclohexene oxide (CHO) and CO2 to high-molecular weight poly(cyclohexene carbonate). However, the presence of PCy3 greatly retarded their ability to homopolymerize CHO to polyether or to afford polyether linkages during the copolymerization of CHO/CO2. PMID:12526468

  8. Synlett 2001 No. 3, 391393 ISSN 0936-5214 Thieme Stuttgart New York New Bifunctional Chelating Phosphine Ligands for Immobilization of Metal

    E-print Network

    Bluemel, Janet

    , and recycle, are much easier to tailor and fine tune than heterogeneous catalysts, and remain as active and se detach from the phosphine linkers, if the catalyst is recycled.6 In order to attach the complexes firmly Achiwa's important work on highly efficient chiral bisphosphine ligands in rhodi- um-catalyzed asymmetric

  9. Direct evidence for the availability of reactive, water soluble phosphorus on the early Earth. H-phosphinic acid from the Nantan meteorite.

    PubMed

    Bryant, David E; Kee, Terence P

    2006-06-14

    Anoxic irradiation of a type IIICD iron meteorite known to contain the phosphide mineral schreibersite (Fe,Ni)3P in the presence of ethanol/water affords the reactive oxyacid H-phosphinic acid (H3PO2) as the dominant phosphorus product. PMID:16733574

  10. A convenient application of the NMR and CD methodologies for the determination of enantiomeric ratio and absolute configuration of chiral atropoisomeric phosphine oxides

    Microsoft Academic Search

    Oleg M. Demchuk; Wioleta ?wierczynska; K. Micha? Pietrusiewicz; Magdalena Wo?nica; Dominik Wójcik; Jadwiga Frelek

    2008-01-01

    Certain commercial carboxylic acids appear to be powerful chiral solvating agents, which allow for a rapid determination of enantiomeric purity and, subject to some limitations, the absolute configuration of common classes of phosphine oxides by means of 1H and\\/or 31P NMR spectroscopy. The complementary application of CD spectroscopic measurement enables the determination of their absolute configuration. Herein, we report a

  11. 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. PMID:22363668

  12. Genetic Linkage Analysis of the Lesser Grain Borer Rhyzopertha dominica Identifies Two Loci That Confer High-Level Resistance to the Fumigant Phosphine

    Microsoft Academic Search

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

    High levels of inheritable resistance to phosphine in Rhyzopertha dominica have recently been detected in Australia and in an effort to isolate the genes responsible for resistance we have used random amplified DNA fingerprinting (RAF) to produce a genetic linkage map of R. dominica. The map consists of 94 dominant DNA markers with an average distance between markers of 4.6

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

    NASA Astrophysics Data System (ADS)

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

    1996-10-01

    Direct reaction of Ph 3P and Ph 2P(CH 2) 2PPh 2 with acrylic acid in AcOEt-acetone yielded the tertiary phosphine betaine triphenylphosphoniopropionate, Ph 3P +(CH 2) 2CO -2 (L 1), and the novel double betaine ethylenebis(diphenylphosphoniopropionate) -O 2C(CH 2) 2Ph 2P +(CH 2) 2Ph 2P +(CH 2) 2CO -2(L 2), respectively. Reaction of Ph 3P with fumaric acid in AcOEt/acetone did not afford the corresponding betaine derivative Ph 3P +CH(CO 2H)CH 2CO -2, but decarboxylates to L 1 in situ. Four adducts of L 1, L 2 and Ph 3P +(CH 2) 3CO -2 (L 3) have been prepared and characterized by single-crystal X-ray analysis. In L 1·2H 2O, 1, two betaine molecules are joined by donor hydrogen bonds from solvated H 2O molecules to form ten-membered rings which are further linked by hydrogen bonds to form chains extending parallel to [1 0 0]. In (HL 1) 2·(O 2CCH?CHCO 2)·HO 2CCH?CHCO 2H·2H 2O, 2, the fumaric acid molecules, fumarate anions and water molecules are interlinked by hydrogen bonds to form layers with an interlayer separation of {1}/{c}? = 10.713(4) Å; the HL 1 cations are sandwiched between adjacent layers and connected to them through hydrogen bonding. In L 2·(CH 3) 2CO·5H 2O, 3, two independent L 2 molecules adopt different orientations and are cross-linked by hydrogen bonds with the water molecules to form layers with an interlayer spacing of {1}/{a}? = 10.341(a) Å; the (CH 3) 2CO molecules are sandwiched between adjacent layers. In [(HL 3) 2(NO 3)]NO 3, 4, two independent HL 3 cations are joined by one of the NO -3 group to form a dimeric cation.

  14. Rationally investigating the influence of T1 location on electroluminescence performance of aryl amine modified phosphine oxide materials.

    PubMed

    Han, Chunmiao; Zhu, Liping; Li, Jing; Zhao, Fangchao; Xu, Hui; Ma, Dongge; Yan, Pengfei

    2014-12-01

    The correspondence between triplet location effect and host-localized triplet-triplet annihilation and triplet-polaron quenching effects was performed on the basis of a series of naphthyldiphenylamine (DPNA)-modified phosphine oxide hosts. The number and ratio of DPNA and diphenylphosphine oxide was adjusted to afford symmetrical and unsymmetrical molecular structures and different electronic environments. As designed, the first triplet (T1 ) states were successfully localized on the specific DPNA chromophores. Owing to the meso- and multi-insulating linkages, identical optical properties and comparable electrical performance was observed, including the same first singlet (S1 ) and T1 energy levels to support the similar singlet and triplet energy transfer and the close frontier molecular orbital energy levels. This established the basis of rational investigation on T1 location effect without interference from other optoelectronic factors. PMID:25303437

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

    PubMed

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

    2007-12-01

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

  16. Tricarbonylrhenium(I) and -technetium(I) complexes with bis(2-pyridyl)phenylphosphine and tris(2-pyridyl)phosphine

    Microsoft Academic Search

    Sonia A. Saucedo Anaya; Adelheid Hagenbach; Ulrich Abram

    2008-01-01

    (NEt4)2[Re(CO)3Br3] or (NEt4)2[Tc(CO)3Cl3] react with bis(2-pyridyl)phenylphosphine (PPhpy2) or tris(2-pyridyl)phosphine (Ppy3) under formation of neutral tricarbonyl complexes of the composition [M(CO)3X(L)] (M=Re, X=Br; M=Tc, X=Cl; L=PPhpy2 or Ppy3). In all isolated products, the ligands coordinate solely via two of their nitrogen atoms. All attempts to force a tripodal coordination of the phosphinopyridines failed. Removal of the bromo ligands from (NEt4)2[Re(CO)3Br3] by

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

    PubMed Central

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

    2014-01-01

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

  18. Acceleration Effects of Phosphine Ligands on the Rhodium-Catalyzed Dehydrogenative Silylation and Germylation of Unactivated C(sp(3))-H Bonds.

    PubMed

    Murai, Masahito; Takeshima, Hirotaka; Morita, Haruka; Kuninobu, Yoichiro; Takai, Kazuhiko

    2015-06-01

    The current work describes the marked rate of acceleration caused by phosphine ligands on the rhodium-catalyzed dehydrogenative silylation and germylation of unactivated C(sp(3))-H bonds. The reactivity was affected by the steric and electronic nature of the phosphine ligands. The use of the bulky and electron-rich diphosphine ligand (R)-DTBM-SEGPHOS was highly effective to yield the dehydrogenative silylation products selectively in the presence of a hydrogen acceptor. An appropriate choice of C2-symmetric chiral diphosphine ligand enables the asymmetric dehydrogenative silylation via the enantioselective desymmetrization of the C(sp(3))-H bond. The unprecedented catalytic germylation of C(sp(3))-H bonds with dehydrogenation was also examined with the combination of the rhodium complex and a wide bite angle diphosphine ligand to provide the corresponding 2,3-dihydrobenzo[b]germoles in good yield. PMID:25961415

  19. Removal of Zinc(II) and Manganese(II) from Crude Phosphoric Media by Bis(2,4,4?Trimethylpentyl) Phosphinic Acid (Cyanex?272)

    Microsoft Academic Search

    N. S. Awwad; E. H. Borai

    2009-01-01

    Purification of commercial phosphoric acid produced by the wet process from toxic heavy metals such as zinc and manganese is considered to be a very important environmental and economical process. The commercial bis(2,4,4?trimethylpentyl)? phosphinic acid (Cyanex?272) is proposed as an extractant for the efficient removal of Zn(II) and Mn(II) from crude phosphoric acid samples of concentrations of 25% and 45%.

  20. Different in vitro and in vivo profiles of substituted 3-aminopropylphosphinate and 3-aminopropyl(methyl)phosphinate GABAB receptor agonists as inhibitors of transient lower oesophageal sphincter relaxation

    PubMed Central

    Lehmann, A; Antonsson, M; Aurell-Holmberg, A; Blackshaw, LA; Brändén, L; Elebring, T; Jensen, J; Kärrberg, L; Mattsson, JP; Nilsson, K; Oja, SS; Saransaari, P; von Unge, S

    2012-01-01

    BACKGROUND AND PURPOSE Gastro-oesophageal reflux is predominantly caused by transient lower oesophageal sphincter relaxation (TLOSR) and GABAB receptor stimulation inhibits TLOSR. Lesogaberan produces fewer CNS side effects than baclofen, which has been attributed to its affinity for the GABA transporter (GAT), the action of which limits stimulation of central GABAB receptors. To understand the structure–activity relationship for analogues of lesogaberan (3-aminopropylphosphinic acids), and corresponding 3-aminopropyl(methyl)phosphinic acids, we have compared representatives of these classes in different in vitro and in vivo models. EXPERIMENTAL APPROACH The compounds were characterized in terms of GABAB agonism in vitro. Binding to GATs and cellular uptake was done using rat brain membranes and slices respectively. TLOSR was measured in dogs, and CNS side effects were evaluated as hypothermia in mice and rats. KEY RESULTS 3-Aminopropylphosphinic acids inhibited TLOSR with a superior therapeutic index compared to 3-aminopropyl(methyl)phosphinic acids. This difference was most likely due to differential GAT-mediated uptake into brain cells of the former but not latter. In agreement, 3-aminopropyl(methyl)phosphinic acids were much more potent in producing hypothermia in rats even when administered i.c.v. CONCLUSIONS AND IMPLICATIONS An enhanced therapeutic window for 3-aminopropylphosphinic acids compared with 3-aminopropyl(methyl)phosphinic acids with respect to inhibition of TLOSR was observed and is probably mechanistically linked to neural cell uptake of the former but not latter group of compounds. These findings offer a platform for discovery of new GABAB receptor agonists for the treatment of reflux disease and other conditions where selective peripheral GABAB receptor agonism may afford therapeutic effects. PMID:21950457

  1. Synthesis and properties of a phosphorus-containing flame retardant epoxy resin based on bis-phenoxy (3-hydroxy) phenyl phosphine oxide

    Microsoft Academic Search

    Hua Ren; Jianzhong Sun; Binjie Wu; Qiyun Zhou

    2007-01-01

    A reactive phosphorus-containing compound, bis-phenoxy (3-hydroxy) phenyl phosphine oxide (BPHPPO) was first successfully synthesized to produce the phosphorus-containing flame retardant epoxy resin (BPHPPO-EP). The chemical structures were characterized from FTIR, MS, NMR spectra and elemental analyses. Thermal degradation behaviors and flame retardant properties of the cured epoxy resins were investigated from the thermogravimetric analysis (TGA) and the limiting oxygen index

  2. Extraction of microamounts of europium and americium into nitrobenzene by using hydrogen dicarbollylcobaltate in the presence of diphenyl-N-butylcarbamoylmethyl phosphine oxide

    Microsoft Academic Search

    E. Makrlík; P. Va?ura; P. Selucký

    2009-01-01

    Extraction of microamounts of europium and americium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H+B?) in the presence of diphenyl-N-butylcarbamoylmethyl phosphine oxide (DPBCMPO, L) has been investigated. The equilibrium data\\u000a have been explained assuming that the complexes HL+, HL2+, ML23+, ML33+ and ML43+ (M3+ = Eu3+, Am3+) are extracted into the organic phase. The values of extraction and stability constants

  3. DETERMINATION OF TOTAL GLUTATHIONE IN CELL LYSATES BY HIGH PERFORMANCE LIQUID CHROMATOGRAPHY WITH O-PHTHALALDEHYDE PRECOLUMN DERIVATIZATION IN THE PRESENCE OF TRIS(2-CARBOXYETHYL)PHOSPHINE

    Microsoft Academic Search

    Ragna Sack; Annemarie Willi; Peter E. Hunziker

    2000-01-01

    A very sensitive HPLC method for the determination of total glutathione (GSH) and ?-glutamyl-cysteine (?-Glu-Cys) content in cell lysates is presented. It is based on a precolumn derivatization with o-phthalaldehyde (OPA) using tris(2-carboxyethyl)-phosphine (TCEP) as a reducing agent. Separation of the peptide derivatives is carried out by reversed-phase chromatography on a C18 column, followed by spectrofluorimetric detection. The fluorescence response

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

    SciTech Connect

    Jones, W.D.; Rosini, G.P.; Maguire, J.A. [Univ. of Rochester, NY (United States). Dept. of Chemistry] [Univ. of Rochester, NY (United States). Dept. of Chemistry

    1999-04-26

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

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

    PubMed

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

    2011-09-01

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

  6. The quaternisation reaction of phosphines and amines in aliphatic alcohols. A similarity analysis using the isokinetic, isosolvent and isoselective relationships.

    PubMed

    Pinheiro, Lidia M V; Calado, António R T; Reis, João Carlos R

    2004-05-01

    Accurate second-order rate constants were measured at 5 K intervals in the temperature range 298.15-328.15 K for the quaternisation reaction of triethylphosphine with iodoethane in methanol, ethanol, propan-1-ol and butan-1-ol. These data are complemented previously reported rate constants for the quaternisation reaction of triethylamine with iodoethane in the same solvents and at similar temperatures. Each of these two reaction series is analysed in terms of the isokinetic relationship (IKR) with respect to solvent variation and of the isosolvent relationship (ISoR) with respect to temperature variation, using in the latter case five different empirical solvent scales. Statistically validated IKR and ISoR have been found for both reaction series. The resulting isokinetic temperatures of 347 K (phosphine series) and of 730 K (amine series) are discussed in terms of Linert's theory of the isokinetic relationship. The best ISoR correlation is obtained using the Dimroth-Reichardt E(T)(N) solvent scale for the phosphine series and the Kamlet-Taft alpha(KT) solvent scale for the amine series. It is demonstrated that no real solvent can be envisaged as having the characteristics of an isokinetic solvent. The selectivity of the nucleophiles triethylphosphine and triethylamine in the attack on iodoethane is examined by treating together both reaction series in terms of the isoselective relationship (ISeR). The isoselective temperature with respect to solvent is found to be 289 K, which is close to the value of 302 K predicted by Exner and Giese's formula on the basis of the individual isokinetic temperatures. A novel ISeR analysis with respect to temperature is performed. It reveals that the alpha(KT) scale is the most appropriate solvent scale for describing this selectivity series, and that it is feasible to find an isoselective solvent. A new equation is developed for predicting the isoselective solvent parameter from individual isosolvent parameters and is shown to yield realistic values. The present similarity analysis shows that there are significant differences between the courses of these quaternisation reactions. On the basis of the experimentally determined isoparameter values, in liquid alcohols as solvent it is proposed that the reaction between triethylphosphine and iodoethane follows a classic bimolecular nucleophilic substitution pathway, whereas the desolvation of triethylamine molecules has to be taken into account to describe the mechanism of the original Menshutkin reaction. PMID:15105923

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

    PubMed

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

    2015-06-01

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

  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. Solid-state sup 31 P NMR, far-IR, and structural studies on two-coordinate (tris(2,4,6-trimethoxyphenyl)phosphine)copper(I) chloride and bromide

    Microsoft Academic Search

    G. A. Bowmaker; J. D. Cotton; P. C. Healy; S. B. Silong; J. D. Kildea; B. W. Skelton; A. H. White

    1989-01-01

    The reactions of acetonitrile solutions of copper(I) chloride, CuCl, and copper(I) bromide, CuBr, with the sterically hindered, highly basic tertiary phosphine ligand tris(2,4,6-trimethoxyphenyl)phosphine ({equivalent to}P(2,4,6)â) have been shown to form 1:1 monomeric adducts, (P(2,4,5)âCuX). The two compounds are isomorphous, crystallizing in the tetragonal space group P4â. For the chloride, a = 15.237 (4) â«, c = 12.373 (3) â«, Z

  10. Pd-Catalyzed Regioselective Alkoxycarbonylation of 1-Alkenes Using a Lewis Acid [SnCl2 or Ti(O(i)Pr)4] and a Phosphine.

    PubMed

    Amézquita-Valencia, Manuel; Achonduh, George; Alper, Howard

    2015-06-19

    The phosphine ligand mediated palladium catalyzed alkoxycarbonylation of alkenes was investigated with the objective of attaining good linear selectivity for the ester. The effect of various parameters such as solvents, additives, palladium precursors, CO pressures, and alkenes of various structural complexities were examined. The results revealed the importance of using a Lewis acid such as SnCl2 or Ti(O(i)Pr)4 in combination with a monodentate ligand such CYTOP 292 or P(p-anisyl)3 to enhance the regioselectivity for the linear isomers in the range of 70-96%. PMID:26005796

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

    PubMed Central

    2013-01-01

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

  12. Tetrameric 1:1 and monomeric 1:3 complexes of silver(I) halides with tri( p-tolyl)-phosphine: A structural and biological study

    Microsoft Academic Search

    Sotiris Zartilas; Sotiris K. Hadjikakou; Nick Hadjiliadis; Nikolaos Kourkoumelis; Loukas Kyros; Maciej Kubicki; Martin Baril; Ian S. Butler; Spyros Karkabounas; Jan Balzarini

    2009-01-01

    Silver(I) halides react with tri(p-tolyl)phosphine (tptp, C21H21P) in MeOH\\/MeCN solutions in 1:1 or 1:3 molar ratios to give complexes of formulae {[AgCl(tptp)]4} (1) or [AgX(tptp)3] (X=Cl (2), Br (3), I (4)), respectively. The complexes were characterized by elemental analyses, and FT-IR far-IR, FT-Raman, TG and 1H, 13C, 31P NMR spectroscopic techniques. Crystal structures of complexes 2–4 were determined by X-ray

  13. Synergistic extraction of rare earths by mixture of bis(2,4,4-trimethylpentyl)phosphinic acid and Sec-nonylphenoxy acetic acid

    Microsoft Academic Search

    Xiaobo Sun; Jinping Wang; Deqian Li; Hongfei Li

    2006-01-01

    Synergistic extraction of trivalent rare earths (RE=Sc, Y, La, Gd, Yb) from hydrochloride medium using mixture of bis(2,4,4-trimethylpentyl)phosphinic acid (HL, Cyanex272) and Sec-nonylphenoxy acetic acid (HA, CA-100) in n-heptane has been studied. The synergistic enhancement coefficients were observed for La (1.30), Gd (1.97), Y (3.59), Yb (8.21) and Sc (14.41). The results indicated yttrium was extracted into n-heptane as YH5A4L4

  14. Phosphidization of GaAs by a remote phosphine plasma process and its application to surface passivation of GaAs metal-semiconductor field-effect transistors

    NASA Astrophysics Data System (ADS)

    Sugino, Takashi; Nozu, Satoshi; Nakajima, Shigeru

    1999-05-01

    Surface passivation of GaAs due to phosphidization is investigated. GaAs surfaces are treated with a remote plasma of phosphine (PH3) diluted with Ar. X-ray photoelectron spectroscopy analysis reveals that the PH3 plasma treatment removes native oxide from GaAs surfaces and that generation of As oxide is suppressed on phosphidized surfaces. Photoluminescence intensity is enhanced for phosphidized GaAs. The PH3 plasma treatment is applied to surface passivation of GaAs metal-semiconductor field-effect transistors. A significant increase of the drain current and the transconductance is achieved. These results strongly suggest that the surface states have been passivated.

  15. AZIDE-SPECIFIC LABELLING OF BIOMOLECULES BY STAUDINGER-BERTOZZI LIGATION: PHOSPHINE DERIVATIVES OF FLUORESCENT PROBES SUITABLE FOR SINGLE-MOLECULE FLUORESCENCE SPECTROSCOPY

    PubMed Central

    Chakraborty, Anirban; Wang, Dongye; Ebright, Yon W.; Ebright, Richard H.

    2010-01-01

    We describe the synthesis of phosphine derivatives of three fluorescent probes that have brightness and photostability suitable for single-molecule fluorescence spectroscopy and microscopy: Alexa488, Cy3B, and Alexa647. In addition, we describe procedures for use of these reagents in azide-specific, bioorthogonal labelling through use of the Staudinger-Bertozzi ligation and procedures for quantitation of labelling specificity and labelling efficiency. The reagents and procedures of this report enable chemoselective, site-selective labelling of azide-containing biomolecules for single-molecule fluorescence spectroscopy and microscopy. PMID:20580957

  16. Synthesis and properties of new tris(cyanoethyl)phosphine complexes of platinum (0,II), palladium (0,II), iridium (I) and rhodium (I)

    Microsoft Academic Search

    A. Guy Orpen; Paul G. Pringle; Martin B. Smith; Kerry Worboys

    1998-01-01

    The tris(cyanoethyl)phosphine (tcep) complexes trans-[PtCl2(tcep)2], cis-[PtMe2(tcep)2], and trans-[PtMeCl(tcep)2] are prepared by treatment of the corresponding [PtXY(cod)] (cod=1,5-cyclooctadiene) with tcep. Reduction of trans-[PtCl2(tcep)2] with NaBH4 gives trans-[PtHCl(tcep)2] which, in the presence of tcep and NEt3, gives the coordinatively unsaturated platinum(0) complex [Pt(tcep)3]. This coordinatively unsaturated species is also formed when [Pt(norbornene)3] reacts with tcep. [Pt(tcep)3] is very unreactive compared to its

  17. Two stage leaching of activated spent HDS catalyst and solvent extraction of aluminium using organo-phosphinic extractant, Cyanex 272.

    PubMed

    Park, Kyung Ho; Mohapatra, Debasish; Nam, Chul-Woo

    2007-09-01

    Spent catalyst generally contains valuable metals like Mo, Co, Ni on a supporting material, such as gamma-A1(2)O(3). In the present study, a two stage alkali/acid leaching process is proposed to selectively target molybdenum and cobalt/nickel separately to facilitate the downstream processing. Prior to the leaching, the spent catalyst was calcined at 500 degrees C to remove C and S; and to convert metal sulphides to metal oxides. 98% Mo, 93% Co and 90% Ni was effectively recovered by this process. The sulphuric acid leaching of spent catalyst, previously treated by alkali solutions to remove Mo, yielded a solution rich in Ni, Co and Al. In order to recover Co and Ni, the Al impurity must be eliminated. The extraction and stripping of Al has been carried out using the organo-phosphinic extractant, Cyanex 272 diluted in carbon tetrachloride. Quantitative Al extraction efficiency was achieved with 1.0M Cyanex 272 in two stages at an aqueous:organic (A:O) phase ratio of 1:1 and equilibrium pH of 3.2. Complete stripping of Al from the loaded organic was carried out using 2M H(2)SO(4) at an A:O phase ratio of 1:1. The extraction reaction proceeded via the cation exchange mechanism and the extracted species was assumed to be AlA(3).3HA. The extraction of Al was carried out in the presence of various ions to ascertain the tolerance limit of individual ions. The regenerated solvent was successfully used for 8 cycles without any significant loss of extraction efficiency, suggesting that Cyanex 272 is extremely stable under present experimental conditions. PMID:17363155

  18. Classical and non-classical phosphine-Ru(II)-hydrides in aqueous solutions: many, various, and useful.

    PubMed

    Papp, Gábor; Horváth, Henrietta; Laurenczy, Gábor; Szatmári, Imre; Kathó, Ágnes; Joó, Ferenc

    2013-01-14

    Hydrogenation of the water-soluble [{RuCl(2)(mtppms)(2)}(2)] (mtppms = monosulfonated triphenylphosphine) was studied in aqueous solutions in the presence of excess mtppms both with H(2) and with aqueous HCOONa. Depending on the reductant, the pH and H(2) pressure altogether nine hydride species were identified. In acidic solutions at 1 bar H(2) pressure the known [RuHCl(mtppms)(3)] (1) and [{RuHCl(mtppms)(2)}(2)] (3) were formed, however, elevated pressure led to the formation of trans-[RuH(2)(mtppms)(4)] (11). In basic solutions at atmospheric pressure cis-fac-[RuH(2)(H(2)O)(mtppms)(3)] (12) was observed which was readily replaced by [RuH(2)(?(2)-H(2))(mtppms)(3)] (13) at higher H(2) pressures. 13 is the first water-soluble and stable ?(2)-H(2) Ru(II)-complex stabilized only by monodentate phosphine ligands. [RuHBr(mtppms)(3)] (9) and [RuHI(mtppms)(3)] (10) were obtained analogously to 1. In concentrated aqueous HCOONa solutions (often used in H-transfer hydrogenations) the major species was trans-[RuH(2)(HCOO)(mtppms)](-) (14) while in dilute solutions trans-[RuH(2)(H(2)O)(mtppms)(3)] (15) could be observed. Formation of these various hydride species offers an explanation for the earlier observed pH and pressure dependence of the rates and selectivities in hydrogenation of unsaturated aldehydes catalyzed by [{RuCl(2)(mtppms)(2)}(2)] + mtppms. PMID:23085748

  19. Synthesis of Polysiloxane-Bound (Ether-phosphine)palladium Complexes. Stoichiometric and Catalytic Reactions in Interphases(1).

    PubMed

    Lindner, Ekkehard; Schreiber, Rudolf; Schneller, Theodor; Wegner, Peter; Mayer, Hermann A.; Göpel, Wolfgang; Ziegler, Christiane

    1996-01-17

    The reaction of two equiv of the monomeric ether-phosphine O,P ligand (MeO)(3)Si(CH(2))(3)(Ph)PCH(2)-Do [1a(T(0)()), 1b(T(0)())] {Do = CH(2)OCH(3) [1a(T(0)())], CHCH(2)CH(2)CH(2)O [1b(T(0)())]} with PdCl(2)(COD) yields the monomeric palladium(II) complexes Cl(2)Pd(P approximately O)(2) [2a(T(0)())(2)(), 2b(T(0)())(2)()]. The compounds 2a(T(0)())(2)() and 2b(T(0)())(2)() are sol-gel processed with variable amounts (y) of Si(OEt)(4) (Q(0)()) to give the polysiloxane-bound complexes 2a(T(n)())(2)()(Q(k)())(y)(), 2b(T(n)())(2)()(Q(k)())(y)() (Table 1) {P approximately O = eta(1)-P-coordinated ether-phosphine ligand; for T(n)() and Q(k)(), y = number of condensed T type (three oxygen neighbors), Q type (four oxygen neighbors) silicon atoms; n and k = number of Si-O-Si bonds; n = 0-3; k = 0-4; 2a(T(n)())(2)()(Q(k)())(y)(), 2b(T(n)())(2)()(Q(k)())(y)() = {[M]-SiO(n)()(/2)(OX)(3)(-)(n)()}(2)[SiO(k)()(/2)(OX)(4)(-)(k)()](y)(), [M] = (Cl(2)Pd)(1/2)(Ph)P(CH(2)Do)(CH(2))(3)-, X = H, Me, Et}. The complexes 2b(T(n)())(2)()(Q(k)())(y)() (y = 4, 12, 36) show high activity and selectivity in the hydrogenation of 1-hexyne and tolan. The dicationic complexes [Pd(P&arcraise;O)(2)][SbF(6)](2) [3a(T(0)())(2)(), 3b(T(0)())(2)()] are formed by reacting Cl(2)Pd(P approximately O)(2) with 2 equiv of a silver salt {P&arcraise;O = eta(2)-O&arcraise;P-coordinated ether-phosphine ligand; 3a(T(0)())(2)(), 3b(T(0)())(2)() = [M]-SiOMe(3); [M] = {[Pd(2+)](1/)(2)P(Ph)(CH(2)CH(2)OCH(3))(CH(2))(3)-}{SbF(6)} (a), {[Pd(2+)](1/)(2)P(Ph)(CH(2)CHCH(2)CH(2)CH(2)O)(CH(2))(3)-}{SbF(6)} (b)}. Their polysiloxane-bound congeners 3a(T(n)())(2)(), 3b(T(n)())(2)() {[M]-SiO(n)()(/2)(OX)(3)(-)(n)} are obtained if a volatile, reversible bound ligand like acetonitrile is employed during the sol-gel process. The bis(chelate)palladium(II) complexes 3a(T(n)())(2)(), 3b(T(n)())(2)() are catalytic active in the solvent-free CO-ethene copolymerization, producing polyketones with chain lengths comparable to those obtained with chelating diphosphine ligands. The polysiloxane-bound palladium(0) complexes 5a(T(n)())(2)()(Q(k)())(4)(), 5b(T(n)())(2)()(Q(k)())(4)() {[M]-SiO(n)()(/)(2)(OX)(3)(-)(n)}(2)[SiO(k)()(/2)(OX)(4)(-)(k)](4), [M] = [(dba)Pd](1/)(2)P(Ph)(CH(2)Do)(CH(2))(3)-} undergo an oxidative addition reaction with iodobenzene in an interphase with formation of the complexes PhPd(I)(P approximately O)(2).4SiO(2) [6a(T(n)())(2)()(Q(k)())(4)(), 6b(T(n)())(2)()(Q(k)())(4)()] {[M]-SiO(n)()(/)(2)(OX)(3)(-)(n)](2)[SiO(k)()(/2)(OX)(4)(-)(k)](4), [M] = [PhPd(I)](1/2)P(Ph)(CH(2)Do)(CH(2))(3)-}, which insert carbon monoxide into the palladium-aryl bond even in the solid state. PMID:11666239

  20. 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. PMID:22722738

  1. Occupational phosphine gas poisoning at veterinary hospitals from dogs that ingested zinc phosphide--Michigan, Iowa, and Washington, 2006-2011.

    PubMed

    2012-04-27

    Zinc phosphide (Zn3P2) is a readily available rodenticide that, on contact with stomach acid and water, produces phosphine (PH3), a highly toxic gas. Household pets that ingest Zn3P2 often will regurgitate, releasing PH3 into the air. Veterinary hospital staff members treating such animals can be poisoned from PH3 exposure. During 2006-2011, CDC's National Institute for Occupational Safety and Health (NIOSH) received reports of PH3 poisonings at four different veterinary hospitals: two in Michigan, one in Iowa, and one in Washington. Each of the four veterinary hospitals had treated a dog that ingested Zn3P2. Among hospital workers, eight poisoning victims were identified, all of whom experienced transient symptoms related to PH3 inhalation. All four dogs recovered fully. Exposure of veterinary staff members to PH3 can be minimized by following phosphine product precautions developed by the American Veterinary Medical Association (AVMA). Exposure of pets, pet owners, and veterinary staff members to PH3 can be minimized by proper storage, handling, and use of Zn3P2 and by using alternative methods for gopher and mole control, such as snap traps. PMID:22534761

  2. N-heterocyclic carbene-assisted, bis(phosphine)nickel-catalyzed cross-couplings of diarylborinic acids with aryl chlorides, tosylates, and sulfamates.

    PubMed

    Ke, Haihua; Chen, Xiaofeng; Zou, Gang

    2014-08-01

    Efficient bis(phosphine)nickel-catalyzed cross-couplings of diarylborinic acids with aryl chlorides, tosylates, and sulfamates have been effected with an assistance of N-heterocyclic carbene (NHC) generated in situ from N,N'-dialkylimidazoliums, e.g., N-butyl-N'-methylimidazolium bromide ([Bmim]Br), in toluene using K3PO4·3H2O as base. In contrast to bis(NHC)nickel-catalyzed conventional Suzuki coupling of arylboronic acids, mono(NHC)bis(phosphine)nickel species generated in situ from Ni(PPh3)2Cl2/[Bmim]Br displayed high catalytic activities in the cross-couplings of diarylborinic acids. The structural influences from diarylborinic acids were found to be rather small, while electronic factors from aryl chlorides, tosylates, and sulfamates affected the couplings remarkably. The couplings of electronically activated aryl chlorides, tosylates, and sulfamates could be efficiently effected with 1.5 mol % NiCl2(PPh3)2/[Bmim]Br as catalyst precursor to give the biaryl products in excellent yields, while 3-5 mol % loadings had to be used for the couplings of non- and deactivated ones. A small ortho-substitutent on the aromatic ring of aryl chlorides, tosylates, and sulfamates was tolerable. Applicability of the nickel-catalyzed cross-couplings in practical synthesis of fine chemicals has been demonstrated in process development for a third-generation topical retinoid, Adapalene. PMID:25025343

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

    Microsoft Academic Search

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

    2010-01-01

    Fumigants and volatile industrial chemicals are particularly hazardous to health when a freight container is fumigated or the contaminated material is introduced into its enclosed environment. Phosphine is now increasingly used as a fumigant, after bromomethane – the former fumigant of choice – has been banned by the Montreal Protocol. We have enhanced our previously established thermal desorption–gas chromatography–mass spectrometry

  4. Iridium(III) Hydrido N-Heterocyclic Carbene–Phosphine Complexes as Catalysts in Magnetization Transfer Reactions

    PubMed Central

    2013-01-01

    The hyperpolarization (HP) method signal amplification by reversible exchange (SABRE) uses para-hydrogen to sensitize substrate detection by NMR. The catalyst systems [Ir(H)2(IMes)(MeCN)2(R)]BF4 and [Ir(H)2(IMes)(py)2(R)]BF4 [py = pyridine; R = PCy3 or PPh3; IMes = 1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene], which contain both an electron-donating N-heterocyclic carbene and a phosphine, are used here to catalyze SABRE. They react with acetonitrile and pyridine to produce [Ir(H)2(NCMe)(py)(IMes)(PPh3)]BF4 and [Ir(H)2(NCMe)(py)(IMes)(PCy3)]BF4, complexes that undergo ligand exchange on a time scale commensurate with observation of the SABRE effect, which is illustrated here by the observation of both pyridine and acetonitrile HP. In this study, the required symmetry breaking that underpins SABRE is provided for by the use of chemical inequivalence rather than the previously reported magnetic inequivalence. As a consequence, we show that the ligand sphere of the polarization transfer catalyst itself becomes hyperpolarized and hence that the high-sensitivity detection of a number of reaction intermediates is possible. These species include [Ir(H)2(NCMe)(py)(IMes)(PPh3)]BF4, [Ir(H)2(MeOH)(py)(IMes)(PPh3)]BF4, and [Ir(H)2(NCMe)(py)2(PPh3)]BF4. Studies are also described that employ the deuterium-labeled substrates CD3CN and C5D5N, and the labeled ligands P(C6D5)3 and IMes-d22, to demonstrate that dramatically improved levels of HP can be achieved as a consequence of reducing proton dilution and hence polarization wastage. By a combination of these studies with experiments in which the magnetic field experienced by the sample at the point of polarization transfer is varied, confirmation of the resonance assignments is achieved. Furthermore, when [Ir(H)2(pyridine-h5)(pyridine-d5)(IMes)(PPh3)]BF4 is examined, its hydride ligand signals are shown to become visible through para-hydrogen-induced polarization rather than SABRE. PMID:24215616

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

    PubMed

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

    2015-06-15

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

  6. Molecular control of the nanoscale: effect of phosphine-chalcogenide reactivity on CdS-CdSe nanocrystal composition and morphology.

    PubMed

    Ruberu, T Purnima A; Albright, Haley R; Callis, Brandon; Ward, Brittney; Cisneros, Joana; Fan, Hua-Jun; Vela, Javier

    2012-06-26

    We demonstrate molecular control of nanoscale composition, alloying, and morphology (aspect ratio) in CdS-CdSe nanocrystal dots and rods by modulating the chemical reactivity of phosphine-chalcogenide precursors. Specific molecular precursors studied were sulfides and selenides of triphenylphosphite (TPP), diphenylpropylphosphine (DPP), tributylphosphine (TBP), trioctylphosphine (TOP), and hexaethylphosphorustriamide (HPT). Computational (DFT), NMR ((31)P and (77)Se), and high-temperature crossover studies unambiguously confirm a chemical bonding interaction between phosphorus and chalcogen atoms in all precursors. Phosphine?chalcogenide precursor reactivity increases in the order: HPTE < TOPE < TBPE < DPPE phosphine, the selenide is always more reactive than the sulfide. CdS(1-x)Se(x) quantum dots were synthesized via single injection of a R(3)PS-R(3)PSe mixture to cadmium oleate at 250 °C. X-ray diffraction (XRD), transmission electron microscopy (TEM), and UV/Vis and PL optical spectroscopy reveal that relative R(3)PS and R(3)PSe reactivity dictates CdS(1-x)Se(x) dot chalcogen content and the extent of radial alloying (alloys vs core/shells). CdS, CdSe, and CdS(1-x)Se(x) quantum rods were synthesized by injection of a single R(3)PE (E = S or Se) precursor or a R(3)PS-R(3)PSe mixture to cadmium-phosphonate at 320 or 250 °C. XRD and TEM reveal that the length-to-diameter aspect ratio of CdS and CdSe nanorods is inversely proportional to R(3)PE precursor reactivity. Purposely matching or mismatching R(3)PS-R(3)PSe precursor reactivity leads to CdS(1-x)Se(x) nanorods without or with axial composition gradients, respectively. We expect these observations will lead to scalable and highly predictable "bottom-up" programmed syntheses of finely heterostructured nanomaterials with well-defined architectures and properties that are tailored for precise applications [corrected]. PMID:22519805

  7. Turning regioselectivity into stereoselectivity: efficient dual resolution of P-stereogenic phosphine oxides through bifurcation of the reaction pathway of a common intermediate.

    PubMed

    Nikitin, Kirill; Rajendran, Kamalraj V; Müller-Bunz, Helge; Gilheany, Declan G

    2014-02-10

    Synthetic routes that provide facile access to either enantiomeric form of a target compound are particularly valuable. The crystallization-free dual resolution of phosphine oxides that gives highly enantioenriched materials (up to 94?% ee) in excellent yields is reported. Both enantiomeric oxides have been prepared from a single intermediate, (RP )-alkoxyphosphonium chloride, which is formed in the course of a selective dynamic kinetic resolution using a single enantiomer of menthol as the chiral auxiliary. The origin of the dual stereoselectivity lies in bifurcation of the reaction pathway of this intermediate, which works as a stereochemical railroad switch. Under controlled conditions, Arbuzov-type collapse of this intermediate proceeds through C?O bond fission with retention of the configuration at the phosphorus center. Conversely, alkaline hydrolysis of the P?O bond leads to the opposite SP ?enantiomer. PMID:24474623

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

    SciTech Connect

    Wang, Chun; Li, Deqian (Changchun Inst. of Applied Chemistry and Physics (China))

    1994-06-01

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

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

    PubMed

    Kumari, A Leela Siva; Swamy, K C Kumara

    2015-04-17

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

  10. NEW DERIVATIVES OF 4,5-BENZO-1,3,2-OXAZA (OR D1AZA)-PHOSPHOLANE FROM CONVENIENT CONDENSATION OF SUBSTITUTED UREA WITH TRIS(DIALKYLAMINO)PHOSPHINE

    Microsoft Academic Search

    Xiao-Bo Ma; Jing-Lin Zhang

    1990-01-01

    The condensation of N-phenyl-N?-(2-hydroxylphenyl)urea or N-phenyl-N?-(2-aminophenyl)urea with tris(dia1kylamino)phosphine afforded derivatives of 4,5-benzo-1,3,2-oxaza (or diaza)-phospholane which formed intramolecular hydrogen bond. The cleavage of the amide bond to give N,N-dialky1-N?-phenylurea together with polymers of 1,3,2-benzodiazaphosphole was observed in the latter reaction.

  11. Determination of total tiopronin in human plasma by LC–ESI–MS using tris (2-carboxy-ethyl) phosphine as reducing reagent and methyl acrylate as derivatization reagent for the thiol group

    Microsoft Academic Search

    Jianfang Liu; Honghai Wu; Yanning Hou

    2006-01-01

    A quantitative method for the determination of total tiopronin (TP) in human plasma was developed by liquid chromatography with electrospray ionisation (ESI) mass spectrometric detection. After reduction with tris (2-carboxy-ethyl) phosphine (TCEP) and derivatization with methyl acrylate (MA) for the thiol group of TP, plasma samples were processed successively by deproteinization and solid phase extraction. N-acetyl-l-cysteine (NAC) was selected as

  12. Comparisons of solid-state and solution structures of (R[sub 3]P)[sub 2]Rh(CO)Cl complexes with monodentate phosphole and phosphine ligands

    SciTech Connect

    Kessler, J.M.; Nelson, J.H. (Univ. of Nevada, Reno (United States)); Frye, J.S. (Colorado State Univ., Ft. Collins (United States)); DeCian, A.; Fischer, J. (Universite Louis Pasteur, Strasbourg (France))

    1993-03-17

    (R[sub 3]P)[sub 2]Rh(CO)Cl complexes have attacted considerable attention. They are catalysts for hydroformylation of alkenes and the nature of the phosphine strongly influences the linear to branched ratio of the aldehyde products. More recently, they have been found to be good catalysts for photolytically promoted C-H bond activation, and their catalytic activity decreases with increasing steric bulk of the phosphine. trans-[(Bu[sup t])[sub 2]PR][sub 2]Rh-(CO)X complexes exhibit hindered rotation about the Rh-P bond in solution as shown by dynamic [sup 31]P NMR studies. [(t-Bu)[sub 3]P][sub 2]-Rh(CO)Cl crystallizes as a distinctly non-planar molecule with considerable tetrahedral distortion. (Ph[sub 3]P)[sub 2]Rh(CO)Cl crystallizes in both monoclinic and triclinic forms, and, also as an orthorhombic CH[sub 2]Cl[sub 2] solvate. Phospholes such as 1-phenyl-3,4-dimethylphosphole (DMPP) and 1-phenyldibenzophosphole (DBP) are phosphorus donors with unusual donor properties. Their (DMPP)[sub 2]Rh(CO)Cl and (DBP)Rh(CO)[sub 2]Cl complexes have been previously described. The analogs (1-phenylphosphole)[sub 2]-Rh(CO)Cl and (3-methyl-1-phenylphosphole)[sub 2]Rh(CO)Cl are among the few examples of such complexes that have been reported to exhibit cis-trans isomerism. As part of continuing programs of investigation of the structure and properties of transition metal phosphole complexes and the utility of CP/MAS [sup 31]P([sup 1]H) NMR spectroscopy for solid-state structural determination, the authors now report on the solution and solid-state characterization of four trans-R[sub 3]P[sub 2]Rh(CO)Cl complexes. Wu and Wasylishen only recently reported the CP/MAS [sup 31]P NMR spectrum of (Ph[sub 3]P)[sub 2]Rh(CO)Cl at the same time as this study was nearing completion.

  13. Production of Galactooligosaccharides Using ?-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

    ?-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

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

    PubMed

    Fu, Qiang; Yang, Limin; Wang, Qiuquan

    2007-06-15

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

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

    PubMed

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

    2010-04-01

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

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

    PubMed Central

    Chen, Su-Ching; Duan, Kow-Jen

    2015-01-01

    ?-Galactosidase was immobilized on chitosan-coated magnetic Fe3O4 nanoparticles and was used to produce galactooligosaccharides (GOS) from lactose. Immobilized enzyme was prepared with or without the coupling agent, tris(hydroxymethyl)phosphine (THP). The two immobilized systems and the free enzyme achieved their maximum activity at pH 6.0 with an optimal temperature of 50 °C. The immobilized enzymes showed higher activities at a wider range of temperatures and pH. Furthermore, the immobilized enzyme coupled with THP showed higher thermal stability than that without THP. However, activity retention of batchwise reactions was similar for both immobilized systems. All the three enzyme systems produced GOS compound with similar concentration profiles, with a maximum GOS yield of 50.5% from 36% (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

  17. Evaluation of microwave irradiation for analysis of carbonyl sulfide, carbon disulfide, cyanogen, ethyl formate, methyl bromide, sulfuryl fluoride, propylene oxide, and phosphine in hay.

    PubMed

    Ren, Yonglin; Mahon, Daphne

    2007-01-10

    Fumigant residues in hay were "extracted" by microwave irradiation. Hay, in gastight glass flasks, was placed in a domestic microwave oven, and fumigants were released into the headspace by microwave irradiation. Power settings for maximum release of fumigants were determined for carbonyl sulfide (COS), carbon disulfide (CS(2)), cyanogen (C(2)N(2)), ethyl formate (EF), methyl bromide (CH(3)Br), sulfuryl fluoride (SF), propylene oxide (PPO), and phosphine (PH(3)). Recoveries of fortified samples were >91% for COS, CS(2), CH(3)Br, SF, PPO, and PH(3) and >76% for C(2)N(2) and EF. Completeness of extraction was assessed from the amount of fumigant retained by the microwaved hay. This amount was determined from further microwave irradiation and was always small (<5% of the amount obtained from the initial procedure). Limits of quantification were <0.1 mg/kg for COS, CS(2), C(2)N(2), EF, and PH(3) and <0.5 mg/kg for CH(3)Br, SF, and PPO. These low limits were essentially due to the absence of interference from solvents and no necessity to inject large-volume gas samples. The microwave method is rapid and solvent-free. However, care is required in selecting the appropriate power setting. The safety implications of heating sealed flasks in microwave ovens should be noted. PMID:17199310

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

    PubMed

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

    2013-05-01

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

  19. Rhodium complexes stabilized by phosphine-functionalized phosphonium ionic liquids used as higher alkene hydroformylation catalysts: influence of the phosphonium headgroup on catalytic activity.

    PubMed

    Luska, Kylie L; Demmans, Karl Z; Stratton, Samantha A; Moores, Audrey

    2012-11-21

    Monodentate phosphine-functionalized phosphonium ionic liquids (PFILs) were employed as ligands for Rh complexes and used in the hydroformylation of higher alkenes. Three PFILs were designed by varying the length of the P-alkyl chain attached to the phosphonium moiety, for alkyl = methyl (1), butyl (2), octyl (3), in order to tune their solubility properties. In all PFILs, the phosphonium unit is linked to a diphenylphosphino functionality by an undecyl linker, with bis(trifluoromethylsulfonyl)imide as counter anion. These PFILs were combined with a Rh(I) precursor, [Rh(acac)(CO)(2)], to provide a biphasic hydroformylation catalyst for the transformation of 1-octene, 1-decene and 1-dodecene using tetradecyltributylphosphonium bis(trifluoromethylsulfonyl)imide, [P(4,4,4,14)]NTf(2) as a solvent. Good activities and excellent selectivities were obtained for these PFILs-Rh(I) complexes. Variation of the P-alkyl length in the PFIL ligand influenced the stability, catalytic activity and selectivity of the PFIL-stabilized catalyst. PMID:23023783

  20. [?-Bis(diphenyl­arsino)methane-1:2?2 As:As?]nona­carbonyl-1?3 C,2?3 C,3?3 C-tricyclo­hexyl­phosphine-3?P-triangulo-triruthenium(0)

    PubMed Central

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

    2009-01-01

    In the title triangulo-triruthenium compound, [Ru3(C25H22As2)(C18H33P)(CO)9], the bis­(diphenyl­arsino)methane ligand bridges an Ru—Ru bond and the monodentate phosphine ligand bonds to the third Ru atom. Both the phosphine and arsine ligands are equatorial with respect to the Ru3 triangle. In addition, each Ru atom carries one equatorial and two axial terminal carbonyl ligands. All three cyclo­hexane rings are disordered over two positions with site occupancies of 0.628?(6) and 0.372?(6). The mean planes of these three phosphine-substituted cyclo­hexane rings make dihedral angles of 53.0?(8), 68.3?(6) and 89.9?(7)° (major components), and 46.7?(14), 41.3?(11) and 75.8?(10)° (minor components) with each other. The dihedral angles between the two phenyl rings are 85.0?(2) and 88.1?(2)° for the two diphenyl­arsino groups. Two cyclo­hexane rings adopt a chair conformation whereas the other adopts a slightly twisted chair conformation for the major components; these conformations are similiar for the minor components. Intra­molecular C—H?O hydrogen bonds stabilize the mol­ecular structure. In the crystal packing, the mol­ecules are linked together into chains via inter­molecular C—H?O hydrogen bonds down the a axis. Weak inter­molecular C—H?? inter­actions further stabilize the crystal structure. PMID:21578646

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

    SciTech Connect

    Schwartz, D.J.; Andersen, R.A. [Lawrence Berkeley Lab., CA (United States)]|[Univ. of California, Berkeley, CA (United States)

    1995-04-12

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

  2. A new coordination mode for tris(2-carboxyethyl)phosphine: Synthesis, crystal structure and characterization of the mixed-valence Co(III)\\/Co(II)\\/Co(III) complex [Co{P(CH 2CH 2COO) 2(CH 2CH 2COOH)} 2] 2[Co(H 2O) 4][Na 2(H 2O) 4]Cl 2 · 6H 2O

    Microsoft Academic Search

    D. Andrew Knight; Jeffrey R. Deschamps; Ray J. Butcher; Christa Simmers; Eddie L. Chang

    2008-01-01

    The water-soluble chelating phosphine ligand tris(2-carboxyethyl)phosphine (TCEP) reacts with cobalt(II) chloride in water to give the mixed-valence Co(III)\\/Co(II)\\/Co(III) complex [Co{P(CH2CH2COO)2(CH2CH2COOH)}2]2[Co(H2O)4][Na2(H2O)4]Cl2·6H2O (1). Structural analysis of 1 using single-crystal X-ray diffraction reveals a trimetallic sodium bridged structure in which TCEP adopts a tridentate chelating mode towards Co(III), and a bridging mode towards Co(II) and Na ions.

  3. {2-[(2-Carbamothiol­ylhydrazin-1-yl­idene-?2 N 1,S)meth­yl]-6-hy­droxy­phenolato-?O 1}(triphenyl­phosphine-?P)nickel(II) chloride

    PubMed Central

    Shawish, Hana Bashir; Tan, Kong Wai; Maah, M. Jamil; Ng, Seik Weng

    2010-01-01

    The deprotonated Schiff base ligand in the title compound, [Ni(C8H8N3O2S)(C18H15P)]Cl, functions as an N,O,S-chelating anion to the phosphine-coordinated Ni atom, which exists in a distorted square-planar geometry. The hy­droxy group forms an intra­molecular O—H?O hydrogen bond. The two amino groups of the cation are hydrogen-bond donors to the chloride anion; the hydrogen bonds generate a chain structure running along the b axis. PMID:21588494

  4. 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.

  5. Air-Stable Gold Nanoparticles Ligated by Secondary Phosphine Oxides as Catalyst for the Chemoselective Hydrogenation of Substituted Aldehydes: a Remarkable Ligand Effect.

    PubMed

    Cano, Israel; Huertos, Miguel A; Chapman, Andrew M; Buntkowsky, Gerd; Gutmann, Torsten; Groszewicz, Pedro B; van Leeuwen, Piet W N M

    2015-06-24

    Air-stable and homogeneous gold nanoparticles (AuNPs, 1a-5a) ligated by various secondary phosphine oxides (SPOs), [R(1)R(2)P(O)H] (R(1) = Naph, R(2) = (t)Bu, L1; R(1) = R(2) = Ph, L2; R(1) = Ph, R(2) = Naph, L3; R(1) = R(2) = Et, L4; R(1) = R(2) = Cy, L5; R(1) = R(2) = (t)Bu, L6), with different electronic and steric properties were synthesized via NaBH4 reduction of the corresponding Au(I)-SPO complex. These easily accessible ligands allow the formation of well dispersed and small nanoparticles (size 1.2-2.2 nm), which were characterized by the use of a wide variety of techniques, such as transmission electron microscopy, thermogravimetric analysis, UV-vis, energy-dispersive X-ray, X-ray photoelectron spectroscopy (XPS), attenuated total reflectance Fourier transform infrared spectroscopy (ATR FT-IR), and cross polarization magic angle spinning (CP MAS) NMR spectroscopy. A pronounced ligand effect was found, and CP MAS NMR experiments enabled us to probe important differences in the polarity of the P-O bond of the SPOs coordinated to the nanoparticle surface depending on the type of substituents in the ligand. AuNPs containing aryl SPOs carry only SPO anions and are highly selective for aldehyde hydrogenation. AuNPs of similar size made with alkyl SPOs contain also SPOH, hydrogen bonded to SPO anions. As a consequence they contain less Au(I) and more Au(0), as is also evidenced by XPS. They are less selective and active in aldehyde hydrogenation and now show the typical activity of Au(0)NPs in nitro group hydrogenation. PMID:26034996

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

    SciTech Connect

    Andersson, Gunther G., E-mail: gunther.andersson@flinders.edu.au, E-mail: vladimir.golovko@canterbury.ac.nz, E-mail: greg.metha@adelaide.edu.au; Al Qahtani, Hassan S. [Flinders Centre for NanoScale Science and Technology, Flinders University, Adelaide SA 5001 (Australia); Golovko, Vladimir B., E-mail: gunther.andersson@flinders.edu.au, E-mail: vladimir.golovko@canterbury.ac.nz, E-mail: greg.metha@adelaide.edu.au [Flinders Centre for NanoScale Science and Technology, Flinders University, Adelaide SA 5001 (Australia); The MacDiarmid Institute for Advanced Materials and Nanotechnology, Department of Chemistry, University of Canterbury, Christchurch 8140 (New Zealand); Alvino, Jason F.; Bennett, Trystan; Wrede, Oliver; Mejia, Sol M.; Metha, Gregory F., E-mail: gunther.andersson@flinders.edu.au, E-mail: vladimir.golovko@canterbury.ac.nz, E-mail: greg.metha@adelaide.edu.au [Department of Chemistry, University of Adelaide, Adelaide SA 5005 (Australia); Adnan, Rohul [The MacDiarmid Institute for Advanced Materials and Nanotechnology, Department of Chemistry, University of Canterbury, Christchurch 8140 (New Zealand); Chemistry Department, University of Malaya, 50603 Kuala Lumpur (Malaysia); Gunby, Nathaniel; Anderson, David P. [The MacDiarmid Institute for Advanced Materials and Nanotechnology, Department of Chemistry, University of Canterbury, Christchurch 8140 (New Zealand)

    2014-07-07

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

  7. Disulfides of manganese carbonyl. Synthesis of Mn(2)(CO)(7)(mu-S2) and its reactions with tertiary phosphines and arsines.

    PubMed

    Adams, Richard D; Kwon, O-Sung; Smith, Mark D

    2002-12-01

    The reaction of Mn(2)(CO)(9)(NCMe) with thiirane yielded the sulfidomanganese carbonyl compounds Mn(2)(CO)(7)(mu-S(2)), 2, Mn(4)(CO)(15)(mu(3)-S(2))(mu(4)-S(2)), 3, and Mn(4)(CO)(14)(NCMe)(mu(3)-S(2))(mu(4)-S(2)), 4, by transfer of sulfur from the thiirane to the manganese complex. Compound 3 was obtained in better yield from the reaction of 2 with CO, and compound 4 is obtained from the reaction of 2 with NCMe. The reaction of 2 with PMe(2)Ph yielded the tetramanganese disulfide Mn(4)(CO)(15)(PMe(2)Ph)(2)(mu(3)-S)(2), 5, and S=PMe(2)Ph. The reaction of 5 with PMe(2)Ph yielded Mn(4)(CO)(14)(PMe(2)Ph)(3)(mu(3)-S)(2), 6, by ligand substitution. The reaction of 2 with AsMe(2)Ph yielded the new complexes Mn(4)(CO)(14)(AsMe(2)Ph)(2)(mu(3)-S(2))(2), 7, Mn(4)(CO)(14)(AsMe(2)Ph)(mu(3)-S(2))(mu(4)-S(2)), 8, Mn(6)(CO)(20)(AsMe(2)Ph)(2)(mu(4)-S(2))(3), 9, and Mn(2)(CO)(6)(AsMe(2)Ph)(mu-S(2)), 10. Reaction of 2 with AsPh(3) yielded the monosubstitution derivative Mn(2)(CO)(6)(AsPh(3))(mu-S(2)), 11. Reaction of 7 with PMe(2)Ph yielded Mn(4)(CO)(15)(AsMe(2)Ph)(2)(mu(3)-S)(2), 12. The phosphine analogue of 7, Mn(4)(CO)(14)(PMe(2)Ph)(2)(mu(3)-S(2))(2), 13, was prepared from the reaction of Mn(2)(CO)(9)(PMe(2)Ph) with Me(3)NO and thiirane. Compounds 2-9 and 11-13 were characterized by single-crystal X-ray diffraction. Compound 2 contains a disulfido ligand that bridges two Mn(CO)(3) groups that are joined by a Mn-Mn single bond, 2.6745(5) A in length. A carbonyl ligand bridges the Mn-Mn bond. Compounds 3 and 4 contain four manganese atoms with one triply bridging and one quadruply bridging disulfido ligand. Compounds 5 and 6 contain four manganese atoms with two triply bridging sulfido ligands. Compound 9 contains three quadruply bridging disulfido ligands imbedded in a cluster of six manganese atoms. PMID:12444771

  8. 147-nm photolysis of phosphine and phosphine-dâ

    Microsoft Academic Search

    J. Blazejowski; F. W. Lampe

    1981-01-01

    The 147-nm photodecompositions of PHâ and PDâ result in the formation of Hâ (Dâ) and PâHâ (PâDâ) in the gas phase and a solid deposit which is probably a mixture of phosphorous and polymeric phosphorous hydrides (PH)\\/sub x\\/ and (PD)\\/sub x\\/. The quantum yields for the gaseous products and for depletion of reactants were measured and were found to increase

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

    PubMed

    Rahaman, Ahibur; Ghosh, Shishir; Unwin, David G; Basak-Modi, Sucharita; Holt, Katherine B; Kabir, Shariff E; Nordlander, Ebbe; Richmond, Michael G; Hogarth, Graeme

    2014-03-24

    The mixed-valence triiron complexes [Fe3(CO)7-x (PPh3) x (?-edt)2] (x = 0-2; edt = SCH2CH2S) and [Fe3(CO)5(?(2)-diphosphine)(?-edt)2] (diphosphine = dppv, dppe, dppb, dppn) have been prepared and structurally characterized. All adopt an anti arrangement of the dithiolate bridges, and PPh3 substitution occurs at the apical positions of the outer iron atoms, while the diphosphine complexes exist only in the dibasal form in both the solid state and solution. The carbonyl on the central iron atom is semibridging, and this leads to a rotated structure between the bridged diiron center. IR studies reveal that all complexes are inert to protonation by 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(?-edt)2](+) and [Fe3(CO)5(?(2)-diphosphine)(?-edt)2](+), species which also result upon oxidation by [Cp2Fe][PF6]. The electrochemistry of the formally Fe(I)-Fe(II)-Fe(I) complexes has been investigated. Each undergoes a quasi-reversible oxidation, the potential of which is sensitive to phosphine substitution, generally occurring between 0.15 and 0.50 V, although [Fe3(CO)5(PPh3)2(?-edt)2] is oxidized at -0.05 V. Reduction of all complexes is irreversible and is again sensitive to phosphine substitution, varying between -1.47 V for [Fe3(CO)7(?-edt)2] and around -1.7 V for phosphine-substituted complexes. In their one-electron-reduced states, all complexes are catalysts for the reduction of protons to hydrogen, the catalytic overpotential being increased upon successive phosphine substitution. In comparison to the diiron complex [Fe2(CO)6(?-edt)], [Fe3(CO)7(?-edt)2] catalyzes proton reduction at 0.36 V less negative potentials. Electronic structure calculations have been carried out in order to fully elucidate the nature of the oxidation and reduction processes. In all complexes, the HOMO comprises an iron-iron bonding orbital localized between the two iron atoms not ligated by the semibridging carbonyl, while the LUMO is highly delocalized in nature and is antibonding between both pairs of iron atoms but also contains an antibonding dithiolate interaction. PMID:24748710

  10. Rh{sub 4} carbonyl clusters coordinated with tris(hydroxymethyl)phosphine grafted onto SiO{sub 2} surfaces and structural control of active sites in gas-phase olefin hydroformylation reactions

    SciTech Connect

    Shido, Takafumi; Okazaki, Takumi; Ichikawa, Masaru [Hokkaido Univ., Sapporo (Japan)] [Hokkaido Univ., Sapporo (Japan)

    1995-12-01

    The structure of attached Rh{sub 4}(CO){sub 12} on tris(hydroxymethyl)-phosphine (P(CH{sub 2}OH){sub 3},THP)-modified silica was investigated by EXAFS and IR spectroscopy. The catalytic behavior of the Rh{sub 4} carbonyl cluster coordinated with THP ligands anchored on SiO{sub 2}(P(CH{sub 2}OH){sub 3-x}(CH{sub 2}OSi){sub x}(x = 1, 2)) in gas-phase hydroformylation reactions was investigated. The number of THP ligands coordinating to the Rh{sub 4} cluster depended on the loading of THP. Rh{sub 4} clusters on SiO{sub 2} loaded with 6.2 wt% THP, on which the average distance of P atoms of the neighboring THP was 8 {angstrom}, were coordinated by two THP ligands, and the Rh{sub 4} clusters were distorted. Rh{sub 4} clusters on SiO{sub 2} loaded with 1.6 wt% THP, on the other hand, were coordinated by one THP ligand and the clusters were not distorted. The attached cluster was active for olefin hydroformylation reaction. The reaction rate of hydroformylation on this catalyst was comparable to that on Wilkinson catalyst in solution. The distorted Rh{sub 4} framework, which is coordinated by two THP, was much more active in hydroformylation reactions than was that of monosubstituted clusters of THP/SiO{sub 2} or Rh{sub 4}(CO){sub 10}(THP){sub 2} in solution. In situ IR spectroscopy and EXAFS revealed that a reversible coordination of CO ligands attached to the Rh{sub 4} cluster was associated with the selective hydroformylation reaction. In the hydroformylation atmosphere, the Rh{sub 4} cluster is almost saturated by CO ligands and effectively suppressed the hydrogenation reaction as a side reaction of hydroformylation. In contrast, under the reaction condition of hydrogenation, CO ligands were removed to increase the reaction rate of hydrogenation. The reversible CO bonding in the surface-grafted Rh{sub 4} site was related to the dynamic control of selective hydroformylation of olefins. 43 refs., 12 figs., 5 tabs.

  11. Application of organolithium compounds for the preparation of some aliphatic and alicyclic phosphines, phosphine oxides and phosphine sulfides 

    E-print Network

    Screttas, Constantinos G

    1961-01-01

    ~~& RNR p o 2HRH 2 50 Oilsaag He aa4 Voraea, Ce Co ~ P ~ diorama ~Ch ai ~op t8, 1C63(1926) ~ ge Williaasi Rt Ho aad Haailtoay Le Le ~ ~be +by 5 $18(1952) ~ 7 ~ Libera~ L aa4 Scholar) '&e ~ ~H? Q6y 23(1913) ~ Si Johaanis, Ri Ai, gee@o r~a. , +, 557... 6? Rosa? p? 0? aa4 IAatooa, 4? 2? ~? 0hoa?? Q? 302{1968) ~ Celestite? L? ~ ~?? g, 2013(1882) ~ Q? Riohoel1e? A? oa4 4ehloak? A?? ~A ~ ? gg? l(1890) ~ b t Rb IY b9 50 51 5R ~ I ~RA R5 b5 55 5b ~ leehal have bees seel ae kgdmlyafag ageatai 51...

  12. Application of organolithium compounds for the preparation of some aliphatic and alicyclic phosphines, phosphine oxides and phosphine sulfides

    E-print Network

    Screttas, Constantinos G

    1961-01-01

    eorroopoa4iag Phosphiaeoc JLP o -0 ~P IR PO k groat rariotp of oxidisiag apostle haes bees eaplopod, ouch as Qreeheel ~ 8 i Oa4 PLShelsteia, ~i, t, gR(1871) ~ 301 Oal ~ Io ~ Qgggk ++0 gg 518(188$) ~ 3 L, Rofaaaa. a ~ L@. . +, )0(18]7) ~ )2i Job, i...6? Rosa? p? 0? aa4 IAatooa, 4? 2? ~? 0hoa?? Q? 302{1968) ~ Celestite? L? ~ ~?? g, 2013(1882) ~ Q? Riohoel1e? A? oa4 4ehloak? A?? ~A ~ ? gg? l(1890) ~ b t Rb IY b9 50 51 5 R ~ I ~RA R 5 b5 55 5b ~ leehal have bees seel ae kgdmlyafag ageatai 51...

  13. X-ray structural investigation of the pentanuclear carbonyl-phosphine cluster of platinum Pt/sub 5/(CO)(. mu. -/sub 2/-CO)/sub 5/(PPh/sub 3/)/sub 4/ in the form of a solvate with three benzene molecules

    SciTech Connect

    Slovokhotov, Yu.L.; Struchkov, Yu.T.

    1987-02-01

    An x-ray structural investigation of the pentanuclear platinum cluster with a carbonyl-phosphine ligand environment Pt/sub 5/(CO)/sub 6/(PPh/sub 3/)/sub 4/ x 3C/sub 6/H/sub 6/ has been carried out (diffractometer, lambdaMo, -120/sup 0/, 9412 reflections, least-squares method in the anisotropic approximation to R = 0.029). The crystals are triclinic, a = 13,454, b = 13.719, c = 24.261 A, ..cap alpha.. = 76.71, ..beta.. = 85.94, ..gamma.. 73.36/sup 0/, the space group is P anti 1, and Z = 2. The Pt/sub 5/ cluster is a tetrahedron with the fifth Pt atom located over one of the edges; the structure of the cluster is similar to that previously investigated by Barbier et al, which is not isomorphous to the solvate of the same compound with three toluene molecules.

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

    SciTech Connect

    de Vries, N.; Cook, J.; Davison, A. (Massachusetts Inst. of Tech., Cambridge (United States)); Jones, A.G. (Harvard Medical School, Boston, MA (United States))

    1991-06-12

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

  15. Structural studies on biaryl phosphines and palladium complexes composed of biaryl phosphines

    E-print Network

    Barder, Timothy E

    2007-01-01

    Pd-catalyzed cross-coupling processes have become one of the most important and useful class of transformations in organic synthesis in the past 25 years. Supporting ligand design has been crucial in developing more effective ...

  16. The synthesis and preparation of some phosphines and phosphine sulfides containing highly condensed aromatic groups 

    E-print Network

    Tefteller, Joseph Wilburn

    1964-01-01

    was than ?ydrolysod with 200 ml. of water and was made alkaline with lO, i aqueous sodium hydroxi. ds. A brown solid material vas separated vith tho water layer, which was filtered, washed with 9gp ethanol and dz'iad in aiz'. 't melted at 2yl-$ Ths... dropwise. Befluxing was continued for 30 min. The reaction mixture was hydrolysed with $0 ml. of water and was made alkaline with 10? aqueous sodium hydroxide. Ths organi. c layer was separated and evaporated under vacuum until a crystalline solid...

  17. The synthesis and preparation of some phosphines and phosphine sulfides containing highly condensed aromatic groups

    E-print Network

    Tefteller, Joseph Wilburn

    1964-01-01

    ] to Bedische Anilin- and Soda-9'abrik A. 0. ). 13, S. Wiohelhaus, Ann. ~su 1. , 6, 257 (1668). lg. Ae Cahours and A. W. Hofmann ~ Ann. & ~10& ~ 1, 29 (1657). aine reagents are generally lower than those obtained from the more easily prepared Qrignard... of noleoulos R3P and R3PS. 6 ban4 present in tho sulfide but absent in the phosphino oan plausibly be assigne4 to the P-S band. The C P ribration in triphenylphosphlno appears at -1 663 sn ~ In highly condensed aronatis groups it would be at slightly lower...

  18. 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.

  19. Retrievals of jovian tropospheric phosphine from Cassini\\/CIRS

    Microsoft Academic Search

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

    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?1 (1000–7 ?m) at a programmable spectral resolution of 0.5 to 15 cm?1. The improved spectral resolution of CIRS over

  20. A Novel Chiral Ferrocenyl Phosphine Ligand from Sugar: Applications in

    E-print Network

    Zhang, Xumu

    , see: (a) Ohkuma, T.; Kitamura, M.; Noyori, R. In Catalytic Asymmetric Synthesis, 2nd ed.; Ojima, I., Yamamoto, H., Eds.; Springer: Berlin, New York, 1999; Vols. I-III. (c) Noyori, R. Asymmetric Catalysis

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

    PubMed

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

    2015-06-01

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

  2. Line positions and intensities of the phosphine (PH3) Pentad near 4.5 ?m

    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 (2?2, ?2 + ?4, 2?4, ?1 and ?3) 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 ?3 and ?1 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.

  3. Phosphine-catalyzed asymmetric additions of malonate esters to gamma-substituted allenoates and allenamides

    E-print Network

    Sinisi, Riccardo

    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 ...

  4. Synthesis of monodisperse cadmium phosphide nanoparticles using ex-situ produced phosphine.

    PubMed

    Miao, Shiding; Hickey, Stephen G; Waurisch, Christian; Lesnyak, Vladimir; Otto, Tobias; Rellinghaus, Bernd; Eychmüller, Alexander

    2012-08-28

    The synthesis of nanoparticles using a gas-liquid interfacial reaction, which for the first time is shown to result in highly monodisperse materials across a range of sizes, is presented. We demonstrate, using cadmium phosphide as the paradigm that this synthesis method can provide colloidal nanocrystals or quantum dots monodisperse enough so that for the first time multiple transitions in their absorbance spectra can be observed. Clear evidence is given that the resulting cadmium material is Cd(6)P(7) and not Cd(3)P(2), and a thorough investigation into the role of temperature and growth time and their effects on the optical properties has been conducted. This strategy can be extended to synthesize other relevant members of the binary component pnictide semiconducting family, and the chemistry of the pnictide compound formation using this synthetic methodology has been explained using the redox potential of the metals. The suitability of the resulting cadmium phosphide quantum dots for applications in light-emitting diodes (LEDs) has further been demonstrated. PMID:22731853

  5. Catalytic hydrogen evolution by Fe(II) carbonyls featuring a dithiolate and a chelating phosphine.

    PubMed

    Roy, Souvik; Mazinani, Shobeir K S; Groy, Thomas L; Gan, Lu; Tarakeshwar, Pilarisetty; Mujica, Vladimiro; Jones, Anne K

    2014-09-01

    Two pentacoordinate mononuclear iron carbonyls of the form (bdt)Fe(CO)P2 [bdt = benzene-1,2-dithiolate; P2 = 1,1'-diphenylphosphinoferrocene (1) or methyl-2-{bis(diphenylphosphinomethyl)amino}acetate (2)] were prepared as functional, biomimetic models for the distal iron (Fe(d)) of the active site of [FeFe]-hydrogenase. X-ray crystal structures of the complexes reveal that, despite similar ?(CO) stretching band frequencies, the two complexes have different coordination geometries. In X-ray crystal structures, the iron center of 1 is in a distorted trigonal bipyramidal arrangement, and that of 2 is in a distorted square pyramidal geometry. Electrochemical investigation shows that both complexes catalyze electrochemical proton reduction from acetic acid at mild overpotential, 0.17 and 0.38 V for 1 and 2, respectively. Although coordinatively unsaturated, the complexes display only weak, reversible binding affinity toward CO (1 bar). However, ligand centered protonation by the strong acid, HBF4·OEt2, triggers quantitative CO uptake by 1 to form a dicarbonyl analogue [1(H)-CO](+) that can be reversibly converted back to 1 by deprotonation using NEt3. Both crystallographically determined distances within the bdt ligand and density functional theory calculations suggest that the iron centers in both 1 and 2 are partially reduced at the expense of partial oxidation of the bdt ligand. Ligand protonation interrupts this extensive electronic delocalization between the Fe and bdt making 1(H)(+) susceptible to external CO binding. PMID:25110946

  6. Geminally diaurated aryls bridged by semirigid phosphine pillars: syntheses and electronic structure.

    PubMed

    Browne, Amberle R; Deligonul, Nihal; Anderson, Bryce L; Rheingold, Arnold L; Gray, Thomas G

    2014-12-22

    Geminally diaurated ?2 -aryl complexes have been prepared where gold(I) centers were bridged by the semirigid diphosphine ligands bis(2-diphenylphosphinophenyl)ether (DPEphos) and 4,6-bis(diphenylphosphanyl)dibenzo[b,d]furan (DBFphos). Diaurated complexes were synthesized in ligand redistribution reactions of the corresponding di-gold dichlorides with di-gold diaryls (six of them new) and silver(I) salts. Diaurated complexes were isolated as salts of the minimally coordinating anions SbF6 (-) and ReO4 (-). Efforts to prepare salts of the tetraarylborate [B(3,5-(CF3)2 C6 H3)4](-) led to transmetalation from boron, with crystallization of the fluorinated aryl complex. The new complexes were characterized by multinuclear NMR, absorption and emission spectroscopies, 77?K emission lifetimes, and by combustion analysis; three are crystallographically characterized. Structures of geminally diaurated aryl ligands are compared to those of mono-aurated analogues. Both crystal structures and density-functional theory calculations indicate slight but observable disruptions of aryl ligand aromaticity by geminal di-gold binding. An intermolecular aurophilic interaction in one structurally authenticated complex was examined computationally. PMID:25351200

  7. 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...

  8. Structural motifs in (t-butoxy) zirconium phosphinates, arsinates, and phosphates.

    PubMed

    Kumara Swamy, K C; Veith, Michael; Huch, Volker; Mathur, Sanjay

    2003-09-22

    Reaction of zirconium tetrakis(tert-butoxide) (1) with dicylohexylphosphinic acid in toluene leads to the dinuclear compound [Zr(mu,mu'-O(2)P(cycl-C(6)H(11))(2))(O-t-Bu)(3)](2) (2) in which the zirconium is pentacoordinated. An analogous reaction using diphenylphosphinic acid in tetrahydrofuran also leads to a dinuclear complex [Zr(mu,mu'-O(2)PPh(2))(THF)((O-t-Bu)(3)](2).C(6)H(5)CH(3) (3.C(6)H(5)CH(3)), in which zirconium is hexacoordinated. A novel exchange of tert-butoxy and phenoxy groups occurs when 1 is treated with diphenyl phosphate [(PhO)(2)PO(2)H] leading to the isolation of the exchange product [Zr(mu,mu'-O(2)P(O-t-Bu)(OPh))(mu-OPh)(O-t-Bu)(2)](2) (4). In contrast to the above, trinuclear zirconium compounds Zr(3(mu,mu'-O(2)AsMe(2))(2)(mu2,mu'-O(2)AsMe(2))(O-t-Bu)(7)(mu-O-t-Bu)(2) (5) and Zr(3(mu,mu'-O(2)P(O-t-Bu)(2))(5)(O-t-Bu)(7).(1)/(2)C(6)H(5)CH(3) (6.(1)/(2)C(6)H(5)CH(3)) have been isolated from the reaction of 1 with cacodylic acid and di-tert-butyl phosphate, respectively. The X-ray structures of 2, 3, 5, and 6 have been determined; although the X-ray structural analysis of 4 could not be satisfactorily finished, it reveals the disposition of the substituents. The solution state NMR data suggest that these compounds undergo structural changes in solution. Possible relationships among the various structures are discussed. PMID:12971751

  9. Bond cleavage reactions in oxygen and nitrogen heterocycles by a rhodium phosphine complex

    SciTech Connect

    Jones, W.D.; Dong, L.; Myers, A.W. (Univ. of Rochester, NY (United States))

    1995-02-01

    The reactions of (C[sub 5]Me[sub 5])Rh(PMe[sub 3])PhH with furan, 2,5-dimethylfuran, 2,3-dihydrofuran, dibenzofuran, pyrrole, 1-methylpyrrole, 2,5-dimethylpyrrole, 1,2,5-trimethylpyrrole, carbazole, 9-methylcarbazole, pyrrolidine, pyridine, 3,5-lutidine, 2,4,6-collidine, pyrazole, 3-methylpyrazole, and piperidine have been investigated. While the oxygen heterocycles give only C-H activation, the nitrogen heterocycles yield C-H and N-H insertion products. The chloro derivative (C[sub 5]Me[sub 5])Rh(PMe[sub 3])[2-(1-methylpyrrole)]Cl was found to crystallize in the monoclinic space group C2/c with a = 13.753 (6) A, b = 9.665 (5) A, c = 30.14 (2) A, [beta] = 99.77 (5)-[degree], Z = 8, and V = 3949 (4.1) A[sup 3] while (C[sub 5]Me[sub 5])Rh(PMe[sub 5])[2-(3,5-lutidine)]Cl was found to crystallize in the monoclinic space group P2[sub 1]/c with a = 14.976 (8) A, b = 8.613 (5) A, c = 17.12 (2) A, [beta] = 101.90 (6)[degree], Z = 4, and V = 2160 (5.2) A[sup 3]. 30 refs., 2 figs., 3 tabs.

  10. SEASONAL AND SPATIAL CHANGES IN INSECT DENSITY IN COMMERCIAL ELEVATOR BINS: IMPLICATIONS FOR PHOSPHINE FUMIGATION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Results of a 5-year, area-wide IPM program for managing insect pests in commercial grain elevators in Kansas and Oklahoma showed that insects generally invaded stored grain from the top of the grain mass. In stored wheat, the rusty grain beetle was the most common insect species from June-September,...

  11. The characterization and reactivity of dinuclear gold complexes containing phosphonium or tertiary phosphine bridging ligands 

    E-print Network

    Diebold, Julia Shain

    1987-01-01

    the gold(III) bridging Table I. Alkyl Halides (RX) Which Porm Gold(II) Adducts Ref. CH 3 CH 3 (CH ) Si. CH 3 3 2 PhCH 2 CH CH 3 2 CP CH 3 2 CH Cl 2 CH Cl 2 CHBr 2 CC1 Br Br Br Br Cl 2, 14 15 15 16 CH CM 2 CH C(0)Ph 2 Br Br...

  12. Alkene isomerization-hydroboration promoted by phosphine-ligated cobalt catalysts.

    PubMed

    Scheuermann, Margaret L; Johnson, Elizabeth J; Chirik, Paul J

    2015-06-01

    Generated in situ from air-stable cobalt precursors or readily synthesized using NaHBEt3, (PPh3)3CoH(N2) was found to be an effective catalyst for the hydroboration of alkenes. Unlike previous base-metal catalysts for alkene isomerization-hydroboration which favor the incorporation of boron at terminal positions, (PPh3)3CoH(N2) promotes boron incorporation adjacent to ?-systems even in substrates where the alkene is at a remote position, enabling a unique route to 1,1-diboron compounds from ?,?-dienes. PMID:26010715

  13. Anti-selective vicinal silaboration and diboration of alkynoates through phosphine organocatalysis.

    PubMed

    Nagao, Kazunori; Ohmiya, Hirohisa; Sawamura, Masaya

    2015-03-01

    Trialkylphosphine organocatalysts have enabled anti-selective vicinal silaboration and diboration of the C-C triple bond in alkynoates to produce ?-boryl-?-silyl acrylates and ?,?-diboryl acrylates, respectively. The anti stereoselectivity was complete and robust. A variety of functional groups were tolerated in the alkynoates. The two vicinally installed heteroatom substituents of the ?-boryl-?-silyl acrylates and ?,?-diboryl acrylates could be differentiated and transformed in a stepwise manner, allowing the synthesis of a diverse array of unsymmetrical tetrasubstituted alkenes. PMID:25675093

  14. 2-Ferrocenyl-2-thiazoline as a building block of novel phosphine-free ligands.

    PubMed

    Corona-Sánchez, Ricardo; Toscano, Rubén A; Ortega-Alfaro, M Carmen; Sandoval-Chávez, César; López-Cortés, José G

    2013-09-01

    New 1,2-disubstituted ferrocenes [5(b-j), in which R = -SMe, -SPh, -SiPr, -SiMe3, -SePh, -SnBu3, -B(OH)2, -Me, -I] with a thiazoline ring in the ferrocene backbone using as key intermediate a ferrocenyl Fischer carbene complex were synthesized. The capability of the 2-thiazoline moiety as an ortho-directed metalation group was demonstrated by subsequent quenching of lithium intermediate with several electrophiles, proving to be an excellent method for synthesizing bidentate ligands. The catalytic scope of the [N,S] ligand 5b as the corresponding palladium complex 5b-PdCl(2) in a microwave-promoted Heck reaction was also tested. Results obtained showed better catalytic activity of 5b-PdCl(2) compared to other catalytic systems based on a [N,S] ferrocenyl ligand. PMID:23824245

  15. Diphosphine Dioxide Cages and Hydrogen Peroxide Adducts of Phosphine Oxides: Syntheses and Applications in Surface Science

    E-print Network

    Hilliard, Casie Renee

    2013-12-09

    the P=O group for probing the surface acidity of oxides. (c) Most importantly, getting more insight regarding the nature of the P=O/surface interaction. Hereby, the mobility of the adsorbed species is of fundamental interest. In the classical 31P MAS...

  16. Design and Characterization of Phosphine Iron Hydrides: Toward Hydrogen-Producing Catalysts.

    PubMed

    Weber, Katharina; Weyhermüller, Thomas; Bill, Eckhard; Erdem, Özlen F; Lubitz, Wolfgang

    2015-07-20

    Diamagnetic iron chloro compounds [(P(Ph)2N(Ph)2)FeCp*Cl] [1Cl] and [(P(Cy)2N(Ph)2)FeCp*Cl] [2Cl] and the corresponding hydrido complexes [(P(Ph)2N(Ph)2)FeCp*H] [1H] and [(P(Cy)2N(Ph)2)FeCp*H] [2H] have been synthesized and characterized by NMR spectroscopy, electrochemical studies, electronic absorption, and (57)Fe Mössbauer spectroscopy (P(Ph)2N(Ph)2 = 1,3,5,7-tetraphenyl-1,5-diphospha-3,7-diazacyclooctane, P(Cy)2N(Ph)2 = 1,5-dicyclohexyl-3,7-diphenyl-1,5-diphospha-3,7-diazacyclooctane, Cp* = pentamethylcyclopentadienyl). Molecular structures of [2Cl], [1H], and [2H], derived from single-crystal X-ray diffraction, revealed that these compounds have a typical piano-stool geometry. The results show that the electronic properties of the hydrido complexes are strongly influenced by the substituents at the phosphorus donor atoms of the P(R)2N(Ph)2 ligand, whereas those of the chloro complexes are less affected. These results illustrate that the hydride is a strong-field ligand, as compared to chloride, and thus leads to a significant degree of covalent character of the iron hydride bonds. This is important in the context of possible catalytic intermediates of iron hydrido species, as proposed for the catalytic cycle of [FeFe] hydrogenases and other synthetic catalysts. Both hydrido compounds [1H] and [2H] show enhanced catalytic currents in cyclic voltammetry upon addition of the strong acid trifluoromethanesulfonimide [NHTf2] (pKa(MeCN) = 1.0). In contrast to the related complex [(P(tBu)N(Bn))2FeCp(C6F5)H], which was reported by Liu et al. (Nat. Chem. 2013, 5, 228-233) to be an electrocatalyst for hydrogen splitting, the here presented hydride complexes [1H] and [2H] show the tendency for electrocatalytic hydrogen production. Hence, the catalytic direction of this class of monoiron compounds can be reversed by specific ligand modifications. PMID:26132460

  17. Line positions and intensities of the phosphine (PH3) Pentad near 4.5 ?m

    SciTech Connect

    Devi, V. Malathy; Kleiner, Isabelle; Sams, Robert L.; Brown, Linda R.; Benner, D. C.; Fletcher, Leigh N.

    2014-04-01

    In order to improve the spectroscopic database for remote sensing of the giant planets, line positions and intensities are determined for the five bands (2?2, ?2 + ?4, 2?4, ?1 and ?3) 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 ?3 and ?1 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.

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

    PubMed Central

    Wilfert, Sandra; Henke, Helena; Schoefberger, Wolfgang; Brüggemann, Oliver; Teasdale, Ian

    2014-01-01

    A simple polymerization of trichlorophosphoranimine (Cl3P = N?SiMe3) mediated by functionalized triphenylphosphines is presented. In situ initiator formation and the subsequent polymerization progress are investigated by 31P NMR spectroscopy, demonstrating a living cationic polymerization mechanism. The polymer chain lengths and molecular weights of the resulting substituted poly(organo)phosphazenes are further studied by 1H NMR spectroscopy and size exclusion chromatography. This strategy facilitates the preparation of polyphosphazenes with controlled molecular weights and specific functional groups at the ?-chain end. Such well-defined, mono-end-functionalized polymers have great potential use in bioconjugation, surface modification, and as building blocks for complex macromolecular constructs. PMID:24700544

  19. Tris[3,5-bis-(trifluoro-meth-yl)phen-yl]phosphine oxide.

    PubMed

    Shawkataly, Omar Bin; Pankhi, Mohd Aslam A; Mohamed-Ibrahim, Mohamed Ismail; Hamdan, M Razak; Fun, Hoong-Kun

    2009-01-01

    In the title compound, C(24)H(9)F(18)OP, an intra-molecular C-H?O short contact generates a five-membered ring, producing an S(5) ring motif. The dihedral angles between the benzene rings are 57.68?(10), 77.80?(11) and 79.48?(10)°. Each of the six trifluoro-methyl substituents shows rotational disorder over two positions with refined site-occupany ratios of 0.64?(3)/0.36?(3), 0.649?(14)/0.351?(14), 0.52?(2)/0.48?(2), 0.545?(16)/0.455?(16), 0.774?(9)/0.226?(9) and 0.63?(5)/0.37?(5). The crystal structure is stabilized by inter-molecular C-H?O and C-H?F inter-actions. PMID:21583895

  20. Phosphinogold(I) Dithiocarbamate Complexes: Effect of the Nature of Phosphine Ligand on Anticancer Properties

    PubMed Central

    2015-01-01

    The reactions of potassium salts of the dithiocarbamates L {where L = pyrazolyldithiocarbamate (L1), 3,5-dimethylpyrazolyldithiocarbamate (L2), or indazolyldithiocarbamate (L3)} with the gold precursors [AuCl(PPh3)], [Au2Cl2(dppe)], [Au2Cl2(dppp)], or [Au2Cl2(dpph)] lead to the new gold(I) complexes [AuL(PPh3)] (1–3), [Au2L2(dppe)] (4–6), [(Au2L2)(dppp)] (7–9), and [Au2(L)2(dpph)] (10–12) {where dppe = 1,2-bis(diphenylphosphino)ethane, dppp = 1,3-bis(diphenylphosphino)propane, and dpph = 1,6-bis(diphenylphosphino)hexane}. These gold compounds were characterized by a combination of NMR and infrared spectroscopy, microanalysis, and mass spectrometry; and in selected cases by single-crystal X-ray crystallography. Compounds 4–6, which have dppe ligands, are unstable in solution for prolonged periods, with 4 readily transforming to the Au18 cluster [Au18S8(dppe)6]Cl2 (4a) in dichloromethane. Compounds 1–3 and 7–12 are all active against human cervical epithelioid carcinoma (HeLa) cells, but the most active compounds are 10 and 11, with IC50 values of 0.51 ?M and 0.14 ?M, 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

  1. Superparamagnetic nanoparticles-supported phosphine-free palladium catalyst for the Sonogashira coupling reaction

    Microsoft Academic Search

    Nam T. S. Phan; Ha V. Le

    2011-01-01

    Superparamagnetic nanoparticles were synthesized following a microemulsion method, and functionalized with Schiff-base groups on the surface to form immobilized bidentate ligands. The functionalized nanoparticles were complexed with palladium acetate, affording the immobilized palladium complex catalyst with a palladium loading of 0.24mmol\\/g. The catalyst was characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), vibrating sample

  2. Synthesis, Characterisation and Antimicrobial Activity of Novel Phosphine Stablised Silver (1) Dicarboxylate Complexes

    Microsoft Academic Search

    Vidya Dixit

    2010-01-01

    The ?, ?-dicarboxylic acids HOOC-(CH2)n-COOH (where n = 1-11) reacted smoothly with [Ag(CH3COO)] to yield 11 novel silver dicarboxylate complexes. These silver dicarboxylates were reacted with triphenylphosphine (PPh3) in 1:2.5, 1:4 and 1:6 molar ratios resulting in the isolation of 30 novel silver dicarboxylate triphenylphosphine derivatives. X-ray crystal structures for nine of these complexes were determined showing a variation in

  3. Phosphine- and hydrogen-free: highly regioselective ruthenium-catalyzed hydroaminomethylation of olefins.

    PubMed

    Gülak, Samet; Wu, Lipeng; Liu, Qiang; Franke, Robert; Jackstell, Ralf; Beller, Matthias

    2014-07-01

    A highly regioselective ruthenium-catalyzed hydroaminomethylation of olefins is reported. Using easily available trirutheniumdodecacarbonyl an efficient sequence consisting of a water-gas shift reaction, hydroformylation of olefins, with subsequent imine or enamine formation and final reduction is realized. This novel procedure is highly practical (ligand-free, one pot) and economic (low catalyst loading and inexpensive metal). Bulk industrial as well as functionalized olefins react with various amines to give the corresponding tertiary amines generally in high yields (up to 92?%), excellent regioselectivities (n/iso>99:1), and full chemoselectivity in favor of terminal olefins. PMID:24861955

  4. Oxidation of heterocyclic amines, sulfilimines, and phosphine imines with dimethyldioxirane. [Aminofurazans

    SciTech Connect

    Coburn, M.D.

    1987-01-01

    Dimethyldioxirane (DMD) reacted with 3-amino-4-(4-chlorophenyl)furazan (1) to yield 3-(4-chlorophenyl)-4-nitrofurazan (5). DMD reacted with the dimethylsulfilimine of 1 to give the sulfoximine with some 5. Treatment of the trioctylphosphine imine (3) with DMD gave only 5. Other reactions with DMD were studied, including the oxidation of aminofurazans. (DLC)

  5. 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…

  6. In vitro Phosphinate Methylation by PhpK from Kitasatospora Phosalacinea

    PubMed Central

    Werner, Williard J.; Allen, Kylie D.; Hu, Kaifeng; Helms, Gregory L.; Chen, Brian S.; Wang, Susan C

    2011-01-01

    Radical SAM (S-adenosyl-L-methionine), cobalamin-dependent methyltransferases have been proposed to catalyze the methylations of unreactive carbon or phosphorus atoms in antibiotic biosynthetic pathways. To date, none of these enzymes have been purified or shown to be active in vitro. Here we demonstrate the activity of the P-methyltransferase enzyme, PhpK, from the phosalacine producer Kitasatospora phosalacinea. PhpK catalyzes the transfer of a methyl group from methylcobalamin to 2-acetylamino-4-hydroxyphosphinylbutanoate (N-acetyldemethylphosphinothricin or NAcDMPT) to form 2-acetylamino-4-hydroxymethylphosphinylbutanoate (N-acetylphosphinothricin or NAcPT). This transformation gives rise to the only carbon-phosphorus-carbon linkage known to occur in Nature. PMID:21950770

  7. Asymmetric nucleophilic catalysis with planar-chiral DMAP derivatives and chiral phosphines : synthetic and mechanistic studies

    E-print Network

    Lee, Sarah Yunmi

    2014-01-01

    Chapter 1 describes the development and detailed mechanistic investigation of the first non-enzymatic method for the dynamic kinetic resolution of secondary alcohols via enantioselective acylation, with acetyl isopropyl ...

  8. Allylic substitution in water catalyzed by amphiphilic resin-supported palladium-phosphine complexes

    Microsoft Academic Search

    Hiroshi Danjo; Daiki Tanaka; Tamio Hayashi; Yasuhiro Uozumi

    1999-01-01

    New amphiphilic resin-supported triarylphosphines PEP (1) were designed and prepared on polyethylene glycol-polystyrene graft copolymer (PEG-PS). Palladium complexes of 1, Pd(PEP)2 (4) and Pd(PEP) (5), catalyzed allylic alkylation of 3-acetoxy-1,3-diphenyl-1-propene (6) and cinnamyl acetate (7) with various nucleophiles including 1,3-dicarbonyl compounds, amino acids, sodium azide, and sodium sulfinate, to give quantitative yields of corresponding allylic substituted products in water.

  9. Complexes between hypohalous acids and phosphine derivatives. Pnicogen bond versus halogen bond versus hydrogen bond.

    PubMed

    Li, Qingzhong; Zhu, Hongjie; Zhuo, Hongying; Yang, Xin; Li, Wenzuo; Cheng, Jianbo

    2014-11-11

    The complexes of HOBr:PH2Y (Y=H, F, Cl, Br, CH3, NH2, OH, and NO2), HOCl:PH2F, and HOI:PH2F have been investigated with ab initio calculations at the MP2/aug-cc-pVTZ level. Four types of structures (1, 2, 3a, and 3b) were observed for these complexes. 1 is stabilized by an O?P pnicogen bond, 2 by a P?X halogen bond, 3a by a H?P hydrogen bond and a P?X pnicogen bond, and 3b by H?P and H?Br hydrogen bonds. Their relative stability is related to the halogen X of HOX and the substituent Y of PH2Y. These structures can compete with interaction energy of -10.22?-29.40 kJ/mol. The HO stretch vibration shows a small red shift in 1, a small irregular shift in 2, but a prominent red shift in 3a and 3b. The XO stretch vibration exhibits a smaller red shift in 1, a larger red shift in 2, but an insignificant blue shift in 3a and 3b. The PY stretch vibration displays a red shift in 1 but a blue shift in 2, 3a, and 3b. The formation mechanism, stability, and properties of these structures have been analyzed with molecular electrostatic potentials, orbital interactions, and non-covalent interaction index. PMID:24878434

  10. 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.

  11. Studies of Soluble Polymer-supported Organocatalysts 

    E-print Network

    Yang, Yun-Chin

    2012-10-19

    soluble polymer-supported phosphines and electronically similar low molecular weight phosphine ligands. The phosphine-silver complexes supported on terminally functionalized polyisobutylene (PIB) and poly(ethylene glycol) show similar kinetic behavior...

  12. C-Cl bond activation of ortho-chlorinated benzamides by nickel and cobalt compounds supported with phosphine ligands.

    PubMed

    Li, Junye; Wang, Chenggen; Li, Xiaoyan; Sun, Hongjian

    2012-07-28

    The C-Cl bonds of ortho-chlorinated benzamides Cl-ortho-C(6)H(4)C(=O)NHR (R = Me (1), nBu (2), Ph (3), (4-Me)Ph (4) and (4-Cl)Ph (5)) were successfully activated by tetrakis(trimethylphosphine)nickel(0) and tetrakis(trimethylphosphine)cobalt(0). The four-coordinate nickel(II) chloride complexes trans-[(C(6)H(4)C([double bond, length as m-dash]O)NHR)Ni(PMe(3))(2)Cl] (R = Me (6), nBu (7), Ph (8) and (4-Me)Ph (9)) as C-Cl bond activation products were obtained without coordination of the amide groups. In the case of 2, the ionic penta-coordinate cobalt(II) chloride [(C(6)H(4)C(=O)NHnBu)Co(PMe(3))(3)]Cl (10) with the [C(phenyl), O(amide)]-chelate coordination as the C-Cl bond activation product was isolated. Under similar reaction conditions, for the benzamides 3-5, hexa-coordinate bis-chelate cobalt(III) complexes (C(6)H(4)C(=O)NHR)Co(Cl-ortho-C(6)H(4)C(=O)NR)(PMe(3))(2) (11-13) were obtained via the reaction with [Co(PMe(3))(4)]. Complexes 11-13 have both a five-membered [C,N]-coordinate chelate ring and a four-membered [N,O]-coordinate chelate ring with two trimethyphosphine ligands in the axial positions. Phosphonium salts [Me(3)P(+)-ortho-C(6)H(4)C(=O)NHR]Cl(-) (R = Ph (14) and (4-Me)Ph (15)) were isolated by reaction of complexes 8 and 9 as a starting material under 1 bar of CO at room temperature. The crystal and molecular structures of complexes 6, 7 and 9-12 were determined by single-crystal X-ray diffraction. PMID:22695972

  13. 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.

  14. [(Z)-O-Isopropyl N-phenyl­thio­car­bam­ato-?S](tricyclo­hexyl­phosphine-?P)gold(I)

    PubMed Central

    Tadbuppa, Primjira P.; Tiekink, Edward R. T.

    2010-01-01

    The Au atom in the title compound, [Au(C10H12NOS)(C18H33P)], is coordinated within an S,P-donor set that defines a slightly distorted linear geometry [S—Au—P = 174.54?(2)°], with the distortion due in part to a close intra­molecular Au?O contact [3.1702?(16)?Å]. In the crystal structure, mol­ecules are arranged into supra­molecular chains along the b axis mediated by C—H?O inter­actions. PMID:21580525

  15. 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. PMID:24871611

  16. Partitioning of Eu(III) between acidic aqueous Al(NO) and tri-n-octyl phosphine oxide

    Microsoft Academic Search

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

    2008-01-01

    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%

  17. Taking TiF4 complexes to extremes--the first examples with phosphine co-ligands.

    PubMed

    Jura, Marek; Levason, William; Petts, Edmund; Reid, Gillian; Webster, Michael; Zhang, Wenjian

    2010-11-14

    The first soft donor adducts of TiF(4), [TiF(4)(diphosphine)] (diphosphine = o-C(6)H(4)(PMe(2))(2), R(2)P(CH(2))(2)PR(2), R = Me or Et) have been prepared from [TiF(4)(MeCN)(2)] and the diphosphines in rigorously anhydrous CH(2)Cl(2), as extremely moisture sensitive yellow solids, and characterised by multinuclear NMR ((1)H, (31)P, (19)F), IR and UV/vis spectroscopy. The crystal structure of [TiF(4){Et(2)P(CH(2))(2)PEt(2)}] has been determined and shows a distorted six-coordinate geometry with disparate Ti-F(transF) and Ti-F(transP) distances and long Ti-P bonds. Weaker soft donor ligands including Ph(3)P, Ph(2)P(CH(2))(2)PPh(2), o-C(6)H(4)(PPh(2))(2), Ph(2)As(CH(2))(2)AsPh(2), o-C(6)H(4)(AsMe(2))(2) and (i)PrS(CH(2))(2)S(i)Pr do not form stable complexes with TiF(4), although surprisingly, fluorotitanate(IV) salts of the previously unknown doubly protonated ligand cations [LH(2)][Ti(4)F(18)] (L = o-C(6)H(4)(PPh(2))(2), o-C(6)H(4)(AsMe(2))(2) and (i)PrS(CH(2))(2)S(i)Pr) are formed in some cases as minor by-products. The structure of [o-C(6)H(4)(PPh(2)H)(2)][Ti(4)F(18)] shows the first authenticated example of a diprotonated o-phenylene-diphosphine. The synthesis and full spectroscopic characterisation are reported for a range of TiF(4) adducts with hard N- or O-donor ligands for comparison purposes, along with crystal structures of [TiF(4)(thf)(2)], [TiF(4)(Ph(3)EO)(2)]·2CH(2)Cl(2) (E = P or As), and [TiF(4)(bipy)]. PMID:20882256

  18. [(Z)-O-Methyl N-(3-chloro­phen­yl)thio­carbamato-?S](tricyclo­hexyl­phosphine-?P)gold(I)

    PubMed Central

    Tadbuppa, Primjira P.; Tiekink, Edward R. T.

    2010-01-01

    Two independent mol­ecules comprise the asymmetric unit of the title compound, [Au(C8H7ClNOS)(C18H33P)], which differ in the relative orientations of each of the cyclo­hexyl groups as well as the benzene ring. In each mol­ecule, the Au atom is coordinated within a S,P-donor set that defines a slightly distorted linear geometry [S—Au—P = 175.10?(5) and 177.26?(5)° for the two mol­ecules], with the distortion due in part to the close intra­molecular approach of the O atom [Au?O contacts = 3.054?(4) and 3.013?(4)?Å, respectively, for the two mol­ecules]. PMID:21580538

  19. Synthesis and Application of New Ligands Derived from N-Heterocyclic Carbenes, Phosphines and Phosphites for Asymmetric Hydrogenations 

    E-print Network

    Khumsubdee, Sakunchai

    2013-11-05

    -methylcinnamic acid W using catalysts formed from the monodentate ligands 27g, 27h, 28g, and 28h with: a Ir(COD)2+; and, b Rh(COD)2+ ........................................................................................... 63 5.11. Hydrogenation of: a... hydroxyester X; and b acetoxyester Y using catalysts formed from the monodentate ligands 27g, 27h, 28g, and 28h with: Ir(COD)2+ ....................................................................................... 65 5.12. Hydrogenation...

  20. Synthesis and Reactivity of Unusual Palladium (II) Complexes Supported by a Diarylamido/BIS(Phosphine) PNP Pincer Ligand 

    E-print Network

    Huacuja, Rafael

    2014-01-17

    . Selected bond distances (Å) and angles (deg): Pd1-C25 2.064(6); Pd1?P1, 2.2779(16); Pd1?P2, 2.3035(17); Pd1?N1, 2.182(5); N1-O1, 3.537(5); NH1-O1 2.870(3); P1?Pd1?P2, 160.21(6)........................154 Figure 4.6 Possible hapticity of arene...

  1. Complexation of Phenols and Thiophenol by Phosphine Oxides and Phosphates. Extraction, Isothermal Titration Calorimetry, and ab Initio Calculations

    Microsoft Academic Search

    Ruud Cuypers; Bernhard Burghoff; Antonius T. M. Marcelis; E. J. R. Sudhölter; Haan de A. B; Han Zuilhof

    2008-01-01

    To develop a new solvent-impregnated resin system for the removal of phenols from water the complex formation of triisobutylphosphine sulfide (TIBPS), tributylphosphate (TBP), and tri-n-octylphosphine oxide (TOPO) with a series of phenols (phenol, thiophenol, 3-chlorophenol, 3,5-dichlorophenol, 4-cyanophenol, and pentachlorophenol) was studied. The investigation of complex formation between the extractants and the phenols in the solvent toluene was carried out using

  2. Complexation of phenols and thiophenol by phosphine oxides and phosphates. Extraction, isothermal titration calorimetry, and ab initio calculations.

    PubMed

    Cuypers, Ruud; Burghoff, Bernhard; Marcelis, Antonius T M; Sudhölter, Ernst J R; de Haan, André B; Zuilhof, Han

    2008-11-20

    To develop a new solvent-impregnated resin system for the removal of phenols from water the complex formation of triisobutylphosphine sulfide (TIBPS), tributylphosphate (TBP), and tri-n-octylphosphine oxide (TOPO) with a series of phenols (phenol, thiophenol, 3-chlorophenol, 3,5-dichlorophenol, 4-cyanophenol, and pentachlorophenol) was studied. The investigation of complex formation between the extractants and the phenols in the solvent toluene was carried out using liquid-liquid extraction, isothermal titration calorimetry (ITC), and quantum chemical modeling (B3LYP/6-311+G(d,p)//B3LYP/6-311G(d,p) and MP2/6-311++G(2d,2p)//B3LYP/6-311G(d,p)). The equilibrium constant (binding affinity, Kchem), enthalpy of complex formation (DeltaH), and stoichiometry (N) were directly measured with ITC, and the entropy of complexation (DeltaS) was derived from these results. A first screening of K chem toward phenol revealed a very high binding affinity for TOPO, and very low binding affinities for the other extractants. Modeling results showed that although 1:1 complexes were formed, the TIBPS and TBP do not form strong hydrogen bonds. Therefore, in the remainder of the research only TOPO was considered. Kchem of TOPO for the phenols in toluene increased from 1,000 to 10,000 M(-1) in the order phenol < pentachlorophenol < 3-chlorophenol < 4-cyanophenol approximately 3,5-dichlorophenol (in line with their pKa values, except for pentachlorophenol) in the absence of water, while the stoichiometric ratio remained 1:1. In water-saturated toluene, the binding affinities are lower due to co-complexation of water with the active site of the extractant. The increase in binding affinity for TOPO in the phenol series was confirmed by a detailed ab initio study, in which Delta H was calculated to range from -10.7 kcal/mol for phenol to -13.4 kcal/mol for 4-cyanophenol. Pentachlorophenol was found to behave quite differently, showing a DeltaH value of -10.5 kcal/mol. In addition, these calculations confirm the formation of 1:1 H-bonded complexes. PMID:18959384

  3. Subtle Modulation of Cu4X4L2 Phosphine Cluster Cores Leads to Changes in Luminescence.

    PubMed

    Chen, Kelly; Shearer, Jason; Catalano, Vincent J

    2015-07-01

    A series of Cu4X4(PPh2py)2 compounds (X = Cl (1), Br (2), I (3), PPh2py = 2-(diphenylphosphino)pyridine) were prepared and characterized using X-ray crystallography, NMR, UV-vis, and luminescence spectroscopy. The copper chloride and bromide clusters have Cu4X4 octahedral cores while the copper iodide clusters contain an unprecedented butterfly shaped core. Crystallization of the copper bromide and iodide clusters from the appropriate solvent produced the solvates 2·2CH2Cl2, 2·2CHCl3, and 3·0.5CH2Cl2 where the presence of the lattice solvate influences the overall structural properties. Using TD-DFT calculations, the emission was assigned to a mixed metal- and halide-to-ligand charge transfer, (M + X)LCT. Subtle differences in the copper core geometry and ?-halide bonding perturb the emissions of these copper(I) halide clusters. PMID:26067759

  4. Synthesis and Reactivity of Unusual Palladium (II) Complexes Supported by a Diarylamido/BIS(Phosphine) PNP Pincer Ligand

    E-print Network

    Huacuja, Rafael

    2014-01-17

    the synthesis and reactivity of [(PNPR)Pd]^(+) (R = ^(i)Pr, ^(t)Bu) cations. [(^(F)PNP^(iPr))Pd]^(+) cations are highly electrophilic complexes that are able to coordinate Lewis bases such as THF, H_(2)O, and even extremely poor Lewis bases such as toluene...

  5. In Vitro and In Vivo Activities of Ruthenium(II) Phosphine/Diimine/Picolinate Complexes (SCAR) against Mycobacterium tuberculosis

    PubMed Central

    Pavan, Fernando R.; Poelhsitz, Gustavo V.; da Cunha, Lucas V. P.; Barbosa, Marilia I. F.; Leite, Sergio R. A.; Batista, Alzir A.; Cho, Sang H.; Franzblau, Scott G.; de Camargo, Mariana S.; Resende, Flávia A.; Varanda, Eliana A.; Leite, Clarice Q. F.

    2013-01-01

    Rifampicin, discovered more than 50 years ago, represents the last novel class of antibiotics introduced for the first-line treatment of tuberculosis. Drugs in this class form part of a 6-month regimen that is ineffective against MDR and XDR TB, and incompatible with many antiretroviral drugs. Investments in R&D strategies have increased substantially in the last decades. However, the number of new drugs approved by drug regulatory agencies worldwide does not increase correspondingly. Ruthenium complexes (SCAR) have been tested in our laboratory and showed promising activity against Mycobacterium tuberculosis. These complexes showed up to 150 times higher activity against MTB than its organic molecule without the metal (free ligand), with low cytotoxicity and high selectivity. In this study, promising results inspired us to seek a better understanding of the biological activity of these complexes. The in vitro biological results obtained with the SCAR compounds were extremely promising, comparable to or better than those for first-line drugs and drugs in development. Moreover, SCAR 1 and 4, which presented low acute toxicity, were assessed by Ames test, and results demonstrated absence of mutagenicity. PMID:23724039

  6. A Stable but Highly Reactive Phosphine-Coordinated Borenium: Metal-free Dihydrogen Activation and Alkyne 1,2-Carboboration.

    PubMed

    Devillard, Marc; Brousses, Rémy; Miqueu, Karinne; Bouhadir, Ghenwa; Bourissou, Didier

    2015-05-01

    Borenium cations have been found to be valuable analogues of boranes as a result of their cationic character which imparts high electrophilicity. Herein, we report the synthesis, characterization, and reactivity of a new type of borenium cation employing a naphthyl bridge and a strong intramolecular P?B interaction. The cation reacts with H2 in the presence of PtBu3 (frustrated Lewis pair (FLP) approach) but also on its own. The mechanism of the reaction between the borenium cation and H2 in the absence of PtBu3 has been investigated using deuterium-labeling experiments and DFT calculations. Both experiments and calculations imply the side-on coordination of H2 to the B?center, followed by heterolytic splitting and B-C bond cleavage. An uncommon syn 1,2-carboboration has also been observed upon reaction of the borenium ion with 3-hexyne. PMID:25800957

  7. Synthesis and Application of New Ligands Derived from N-Heterocyclic Carbenes, Phosphines and Phosphites for Asymmetric Hydrogenations

    E-print Network

    Khumsubdee, Sakunchai

    2013-11-05

    (R)-baclofen,102-104 (S)-pregabalin,105-107 and (S)-vigabatrin.108-110 Not only interacts with GABA receptors, some ?-amino acid derivatives, such as statine, also act as an inhibitor of aspartic acid protease which is an important part... selectively interact with receptors modulated by GABA, including baclofen,111-113 pregabalin,114 vigabatrin,109 the experimental therapeutics in Figure 2.2, and tubulysins. Consequently, asymmetric syntheses of these fragments have been a focus of attention...

  8. Ni(II), Pd(II) and Pt(II) complexes of PNP and PSP tridentate amino-phosphine ligands.

    PubMed

    Sgro, Michael J; Stephan, Douglas W

    2012-06-14

    The ligands D((CH(2))(2)NHPiPr(2))(2) (D = NH 1, S 2) react with (dme)NiCl(2) or (PhCN)(2)MCl(2) (M = Pd, Pt) to give complexes of the form [D((CH(2))(2)NHPiPr(2))(2)MX]X (X = Cl, I; M = Ni, Pd, Pt) which were converted to corresponding iodide derivatives by reaction with Me(3)SiI. Reaction of 1 or 2 with (COD)PdMeCl affords facile routes to [?(3)P,N,P-NH((CH(2))(2)NHPiPr(2))(2)PdMe]Cl (8a) and [?(3)P,S,P-S((CH(2))(2)NHPiPr(2))(2)PdMe]Cl (9a) in high yields. An alternative synthetic approach involves oxidative addition of MeI to a M(0) precursor yielding [?(3)P,N,P-HN(CH(2)CH(2)NHPiPr(2))(2)NiMe]I (10), [?(3)P,N,P-HN(CH(2)CH(2)NHPiPr(2))(2)MMe]I (M = Pd 8b Pt 11) and [?(3)P,S,P-S(CH(2)CH(2)NHPiPr(2))(2)MMe]I (M = Pd 9b, Pt 12). Alternatively, use of NEt(3)HCl in place of MeI produces the species [?(3)P,N,P-HN(CH(2)CH(2)NHPiPr(2))(2)MH]X (X = Cl, M = Ni 13a, Pd 14a, Pt 16a). The analogs containing 2; [?(3)P,S,P-S((CH(2))(2)NHPiPr(2))(2)MH]X (M = Pd, X = PF(6)15: M = Pt, X = Br, 17a, PF(6)17b) were also prepared in yields ranging from 74-93%. In addition, aryl halide oxidative addition was also employed to prepare [?(3)P,N,P-HN(CH(2)CH(2)NHPiPr(2))(2)MC(6)H(4)F]Cl (M = Ni 18, Pd 19) and [?(3)P,S,P-S((CH(2))(2)NHPiPr(2))(2)Pd(C(6)H(4)F)]Cl (20). Crystal structures of 3a, 4a, 5a, 6a, 8a, 9a, 14b and 16b are reported. PMID:22535417

  9. Efficient Synthesis of Fmoc-Protected Phosphinic Pseudodipeptides: Building Blocks for the Synthesis of Matrix Metalloproteinase Inhibitors

    E-print Network

    Lepore, Salvatore D.

    for the Synthesis of Matrix Metalloproteinase Inhibitors Manishabrata Bhowmick,1 Ravinder R. Sappidi,1 Gregg B) inhibitors as activa- tion of these enzymes have been associated with primary and metastatic tumor growth to the design of an inhibitor of metallo-proteases involves replacing a trigonal planar amide or ester bond

  10. Bypassing a highly unstable frustrated Lewis pair: dihydrogen cleavage by a thermally robust silylium-phosphine adduct.

    PubMed

    Herrington, Thomas J; Ward, Bryan J; Doyle, Laurence R; McDermott, Joe; White, Andrew J P; Hunt, Patricia A; Ashley, Andrew E

    2014-10-28

    The thermally robust silylium complex [iPr3Si-PtBu3](+)[B(C6F5)4](-) (1) activates H2/D2 at 90 °C (PhCl); no evidence for dissociation into the separated Lewis pair is found. DFT calculations show H2 cleavage proceeds via Si-P bond elongation to form an encounter complex directly from the adduct, thus avoiding the non-isolable iPr3Si(+)-PtBu3 FLP. PMID:25204297

  11. A Bulky Biaryl Phosphine Ligand Allows for Palladium-Catalyzed Amidation of Five-Membered Heterocycles as Electrophiles

    E-print Network

    Su, Mingjuan

    The incredible bulk: The first palladium-catalyzed amidation of five-membered heterocyclic bromides with multiple heteroatoms was achieved using the Pd/1 catalyst system. N-Arylated imidazoles, pyrazoles, thiazoles, pyrroles, ...

  12. Mass spectrometric studies of phosphine pyrolysis and OMVPE growth of InP. [organometallic vapor phase epitaxy

    NASA Technical Reports Server (NTRS)

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

    1987-01-01

    The mechanism of PH3 decomposition was studied by using D2 as a carrier gas and analyzing the reaction products with a mass spectrometer. The effects of InP and silica surfaces were investigated. The only gaseous product below 600 C is H2. Since any gas-phase H atoms would produce HD, the reaction occurs entirely on the surface. The slow step is the unimolecular removal of the first hydrogen atom, with an activation energy of 36.0 kcal/mole on InP surfaces. The reaction on InP is first-order for PH3 concentrations as high as 15 percent, so the surface is not saturated at those conditions. When trimethylindium (TMIn) is added to the gas mixture, the mechanism changes dramatically, probably proceeding via an unstable intermediate adduct of TMIn and PH3 which eliminates CH4 upon formation. This concerted reaction lowers the pyrolysis temperatures of both PH3 and TMIn.

  13. 2648 J. Org. Chem. 1991,56,2648-2650 Selective Reduction of Disulfides by Tris(2-carboxyethy1)phosphine

    E-print Network

    Prentiss, Mara

    (TCEP)reduces disulfidesrapidly and completely in water at pH 4.5. It preferentially reduces more a convenient preparation of tris(2- carboxyethy1)phosphinehydrochloride (TCEP.HC1,l.HCl) by acidic hydrolysis.; Maclaren, J. A. Aust. J. Chem. 1966, 19, 2347-2354. utility of TCEP as a selective reducing agent for repre

  14. Preparation of phosphine-functionalized polystyrene stars by metal catalyzed controlled radical copolymerization and their application to hydroformylation catalysis.

    PubMed

    Cardozo, Andrés F; Manoury, Eric; Julcour, Carine; Blanco, Jean-François; Delmas, Henri; Gayet, Florence; Poli, Rinaldo

    2013-07-01

    Well defined star copolymers have been prepared by copper-catalyzed atom transfer radical copolymerization of styrene and styryldiphenylphosphine starting from a modified Boltorn™ H30 multifunctional initiator. These polymers and an analogue obtained by debromination of the arm ends with nBu3SnH have been used in combination with [Rh(acac)(CO)2] for the homogeneous phase hydroformylation of 1-octene. PMID:23487263

  15. A Single Phosphine Ligand Allows Palladium-Catalyzed Intermolecular C-O Bond Formation with Secondary and Primary Alcohols

    E-print Network

    Wu, Xiaoxing

    Forging a bond: An efficient, general palladium catalyst for C-O bond-forming reactions of secondary and primary alcohols with a range of aryl halides has been developed using the ligand 1. Heteroaryl halides, and for the ...

  16. Tridentate Phosphine Linkers for Immobilized Catalysts: Development and Characterization of Immobilized Rhodium Complexes and Solid-State NMR Studies of Polymers 

    E-print Network

    Guenther, Johannes 1983-

    2012-08-16

    of performance polymers with solid2state NMR techniques. First a brief overview of solid2state NMR and its relevance to the various areas of chemistry covered in this thesis is given. Following the synthesis, immobilization, and characterization of tridentate...

  17. EQUILIBRIA INVOLVING COBALT(II) HALIDES AND PHOSPHINE OXIDES I. A SPECTROPHOTOMETRIC STUDY OF THE COBALT(II) CHLORIDE — TRIPHENYLPHOSPHINE OXIDE SYSTEM IN ACETONE MEDIUM

    Microsoft Academic Search

    M. Molina; C. V. Melios; A. C. Massabni; T. Takaki

    1978-01-01

    The CoCl2-triphenylphosphine oxide system was studied in anhydrous acetone medium, at 25.00 · 0.05 ° C, by spectrophotometry. It was found that the system comprises at least three complex species, whose over-all stability constants are: ?1 = (1.40 · 0.10) · 10 M, ?2 = (6.77 · 0.95) · 10 M, ?3 = (1.77 · 0.40) · 10 M The

  18. Telomerisation of buta-1,3-diene and methanol: superiority of chromanyl-type phosphines in the Dow process for the industrial production of 1-MOD.

    PubMed

    Tschan, Mathieu J-L; Launay, Hélène; Hagen, Henk; Benet-Buchholz, Jordi; van Leeuwen, Piet W N M

    2011-08-01

    Butadiene and methanol were telomerised in the presence of palladium catalysts with ligands containing 8-diphenylphosphinochromane-like substituents at phosphorus. MonoXantphos and monoSPANphos afforded the most active, stable and selective catalysts known to date under commercially relevant production conditions for 1-methoxyocta-2,7-diene, the precursor to oct-1-ene. PMID:21695740

  19. Synthesis, structure, and electrochemistry of di- and zerovalent nickel, palladium, and platinum monomers and dimers derived from an enantiopure (S,S)-tetra(tertiary phosphine).

    PubMed

    Kitto, Heather J; Rae, A David; Webster, Richard D; Willis, Anthony C; Wild, S Bruce

    2007-09-17

    The ligand (S,S)-1,1,4,7,10,10-hexaphenyl-1,4,7,10-tetraphosphadecane, (S,S)-tetraphos, reacts with hexa(aqua)nickel(II) chloride in the presence of trimethylsilyl triflate (TMSOTf) in dichloromethane to give the yellow square-planar complex [Ni{(R,R)-tetraphos}](OTf)2, which has been crystallographically characterized as the square-pyramidal, acetonitrile adduct [Ni(NCMe){(R,R)-tetraphos}]OTf. Cyclic voltammograms of the nickel(II) complex in dichloromethane and acetonitrile at 20 degrees C showed two reduction processes at negative potentials with oxidative (E(p)(ox)) and reductive (E(p)(red)) peak separations similar to those observed for ferrocene/ferrocenium under identical conditions, suggesting two one-electron steps. The cyclic voltammetric data for the divalent nickel complex in acetonitrile at temperatures below -20 degrees C were interpreted according to reversible coordination of acetonitrile to the nickel(I) and nickel(0) complexes. The divalent palladium and platinum complexes [M{(R,R)-tetraphos}](PF6)2 and [M2{(R,R)-tetraphos}2](OTf)4 have been prepared. The reduction potentials for the complexes [M{(R,R)-tetraphos}](PF6)2 increase in the order nickel(II) < palladium(II) < platinum(II). The reaction of (S,S)-tetraphos with bis(cycloocta-1,5-diene)nickel(0) in benzene affords orange [Ni{(R,R)-tetraphos}], which slowly rearranges into the thermodynamically more stable, yellow, double-stranded helicate [Ni2{(R,R)-tetraphos}2]; the crystal structures of both complexes have been determined. The reactions of (S,S)-tetraphos with [M(PPh3)4] in toluene (M = Pd) or benzene (M = Pt) furnish the double-stranded helicates [M2{(R,R)-tetraphos}2]; the palladium complex crystallizes from hot benzene as the 2-benzene solvate and was structurally characterized by X-ray crystallography. In each of the three zerovalent complexes, the coordinated (R,R)-tetraphos stereospecifically generates tetrahedral M(PP)2 stereocenters of M configuration. PMID:17696428

  20. 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.

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

    PubMed

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

    2015-04-17

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

  2. Aldehyde and phosphinate analogs of glutathione and glutathionylspermidine: potent, selective binding inhibitors of the E. coli bifunctional glutathionylspermidine synthetase\\/amidase

    Microsoft Academic Search

    Chun-Hung Lin; Shoujun Chen; David S. Kwon; James K. Coward; Christopher T. Walsh

    1997-01-01

    Introduction: The tripeptide glutathione is converted to glutathionylspermidine (Gsp) in Escherichia coli and in trypanosomatid parasites by an ATP-cleaving Gsp synthetase activity. In parasites, an additional glutathionylation forms bis-(glutathionyl)-spermidine, trypanothione, believed to be the major surveillance thiol involved in oxidant defense mechanisms in trypanosomatid parasites. In E. coli, the Gsp synthetase is part of a bifunctional enzyme opposed by the

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

    SciTech Connect

    Bullock, R.M.; Ghosh, P.; Fagan, P.J.; Marshall, W.J.; Hauptman, E.

    2009-07-20

    A ruthenium hydride with a bulky tetra-substituted Cp ligand, (Cp{sup iPr{sub 4}})Ru(CO){sub 2}H (Cp{sup iPr{sub 4}} = C{sub 5}(i-C{sub 3}H{sub 7}){sub 4}H) was prepared from the reaction of Ru{sub 3}(CO){sub 12} with 1,2,3,4-tetraisopropylcyclopentadiene. The molecular structure of (Cp{sup iPr{sub 4}})Ru(CO){sub 2}H was determined by X-ray crystallography. The ruthenium hydride complex (C{sub 5}Bz{sub 5})Ru(CO){sub 2}H (Bz = CH{sub 2}Ph) was similarly prepared. The Ru-Ru bonded dimer, [(1,2,3-trimethylindenyl)Ru(CO){sub 2}]{sub 2}, was produced from the reaction of 1,2,3-trimethylindene with Ru{sub 3}(CO){sub 12}, and protonation of this dimer with HOTf gives {l_brace}[(1,2,3-trimethylindenyl)Ru(CO){sub 2}]{sub 2}-({mu}-H){r_brace}{sup +}OTf{sup -}. A series of ruthenium hydride complexes CpRu(CO)(L)H [L = P(OPh){sub 3}, PCy{sub 3}, PMe{sub 3}, P(p-C{sub 6}H{sub 4}F){sub 3}] were prepared by reaction of Cp(CO){sub 2}RuH with added L. Protonation of (Cp{sup iPr{sub 4}})Ru(CO){sub 2}H, Cp*Ru(CO){sub 2}H, or CpRu(CO)[P-(OPh){sub 3}]H by HOTf at -80 C led to equilibria with the cationic dihydrogen complexes, but H{sub 2} was released at higher temperatures. Protonation of CpRu[P(OPh){sub 3}]{sub 2}H with HOTf gave an observable dihydrogen complex, {l_brace}CpRu[P-(OPh){sub 3}]{sub 2}({eta}{sup 2}-H{sub 2}){r_brace}+OTf{sup -} that was converted at -20 C to the dihydride complex {l_brace}CpRu[P(OPh){sub 3}]{sub 2}(H){sub 2}{r_brace}{sup +}OTf{sup -}. These Ru complexes serve as catalyst precursors for the catalytic deoxygenation of 1,2-propanediol to give n-propanol. The catalytic reactions were carried out in sulfolane solvent with added HOTf under H{sub 2} (750 psi) at 110 C.

  4. Monometallic Ni(0) and Heterobimetallic Ni(0) /Au(I) Complexes of Tripodal Phosphine Ligands: Characterization in Solution and in the Solid State and Catalysis.

    PubMed

    Cluff, Kyle J; Bhuvanesh, Nattamai; Blümel, Janet

    2015-07-01

    The tridentate chelate nickel complexes [(CO)Ni{(PPh2 CH2 )3 CMe}] (2), [(CO)Ni{(PPh2 CH2 CH2 )3 SiMe}] (6), and [Ph3 PNi{(PPh2 CH2 CH2 )3 SiMe}] (7), as well as the bidentate complex [(CO)2 Ni{(PPh2 CH2 )2 CMeCH2 PPh2 }] (3) and the heterobimetallic complex [(CO)2 Ni{(PPh2 CH2 )2 CMeCH2 Ph2 PAuCl}] (4), have been synthesized and fully characterized in solution. All (1) H and (13) C?NMR signal assignments are based on 2D-NMR methods. Single crystal X-ray structures have been obtained for all complexes. Their (31) P?CP/MAS (cross polarization with magic angle spinning) NMR spectra have been recorded and the isotropic lines identified. The signals were assigned with the help of their chemical shift anisotropy (CSA) data. All complexes have been tested regarding their catalytic activity for the cyclotrimerization of phenylacetylene. Whereas complexes 2-4 display low catalytic activity, complex 7 leads to quantitative conversion of the substrate within four hours and is highly selective throughout the catalytic reaction. PMID:26059108

  5. Chiral separation of phosphine-containing alpha-amino acid derivatives using two complementary cellulosic stationary phases in supercritical fluid chromatography.

    PubMed

    West, Caroline; Bouet, Alexis; Gillaizeau, Isabelle; Coudert, Gerard; Lafosse, Michel; Lesellier, Eric

    2010-02-01

    Enantiomeric separations of six amino-acid derivatives have been studied using packed-column supercritical fluid chromatography with two polysaccharide-based enantioselective stationary phases: cellulose tris(3,5-dimethylphenylcarbamate) and cellulose tris(3-chloro-4-methylphenylcarbamate) (Lux Cellulose-1 and -2). The effect of analyte structure on retention and separation was studied. Varied mobile phase compositions were investigated: alcohol modifier percentage was increased from 3 to 40% but smaller amounts were most effective in separating these compounds. Besides, ethanol was preferred to methanol or isopropanol as it proved to be a good compromise to achieve sufficient resolution in a reasonable analysis time. Moreover, a carbon dioxide-ethanol mixture allows performing analyses in safe and green conditions. The effect of temperature at constant mobile phase composition was explored between 10 and 40 degrees C. In most cases, increasing the temperature improved the chiral separation, up to an optimum temperature. The results are discussed in line with the structure variation of the racemic derivatives analyzed and the two columns are compared. The two columns were shown to provide complementary selectivities for the investigated solutes: whereas Lux 1 provided separation for five of the six racemates, Lux 2 could resolve the last racemic mixture. Finally, optimized conditions of separation are defined. PMID:19551878

  6. Tridentate Phosphine Linkers for Immobilized Catalysts: Development and Characterization of Immobilized Rhodium Complexes and Solid-State NMR Studies of Polymers

    E-print Network

    Guenther, Johannes 1983-

    2012-08-16

    ) polymers. 13C CP/MAS (cross polarization with magic angle spinning) NMR and IR spectroscopy reveal that PEEK polymers show no detectable chemical change on the molecular level, while PPS polymers display signs of oxidation of the thioether group...

  7. Rapid, covalent addition of phosphine to dithiolene in a molybdenum tris(dithiolene). A new structural model for dimethyl sulfoxide reductase.

    PubMed

    Nguyen, Neilson; Lough, Alan J; Fekl, Ulrich

    2012-06-18

    Triphenylphosphine (PPh(3)) rapidly and reversibly adds to the bdt ligand in the molybdenum tris(dithiolene) complex Mo(tfd)(2)(bdt) [tfd = S(2)C(2)(CF(3))(2); bdt = S(2)C(6)H(4)], turning chelating bdt into the monodentate zwitterionic ligand SC(6)H(4)SPPh(3). A second PPh(3) molecule fills the newly created open site in the crystallographically characterized product Mo(tfd)(2)(SC(6)H(4)SPPh(3))(PPh(3)), which is a structural model for dimethyl sulfoxide (DMSO) reductase. While the complex is only a precatalyst for reduction of DMSO by PPh(3) (the initially low catalytic rate increases with time), Mo(tfd)(2)(SMe(2))(2) was found to be catalytically active without an induction period. PMID:22646474

  8. Study on the europium-2-benzoyl-indan-1,3-dione-trioctyl-phosphine oxide-triton X-100 fluorescence system and its analytical application

    SciTech Connect

    Zhikun Si; Wei Jiang; Jingtian Hu [Shandong Univ., Jinan (China)] [and others

    1996-01-01

    A study on the fluorescence system of the Eu{sup 2+}-2-benzoyl-indan-1,3-dione-triocytylphosphine oxide-Triton X-100 was made. The excitation and emission wavelengths were 348 and 612 nm, respectively. The fluorescence intensity was a linear function of the concentration of europium in the range 1.0x10{sup -8} - 1.0x10{sup -6} mol/L. The detection limit was 4.0x10{sup -9} mol/L. The standard addition method was used for the determination of europium in rare earth oxides, with satisfactory results.

  9. Magnetic carrier for radionuclide removal from aqueous wastes: Parameters investigated in the development of nanoscale magnetite based carbamoyl methyl phosphine oxide

    Microsoft Academic Search

    R. D. a Ambashta; P. K. a Wattal; S. b Singh; D. c Bahadur

    2006-01-01

    A study on superparamagnetic magnetite polymer composite development was undertaken for application to magnetically assisted chemical separation. Tetramethyl ammonium hydroxide as an alternative to ammonia was used as a precipitation agent to obtain nanoscale magnetite particles. Investigation on stoichiometry control of Fe(III) and Fe(II) ions suggested a correlation between alkalinity and initial Fe(III): Fe(II) ratio for precipitation of magnetite. Studies

  10. 218 Inorg. Chem. 1993, 32, 218-222 Synthesis, X-ray CrystalStructure, and Phosphine-Exchange Reactions of the

    E-print Network

    Girolami, Gregory S.

    -Exchange Reactions of the Hafnium(III)-Hafnium(II1)Dimer HfiCb(PEt& Matthew E.Riehl, Scott R. Wilson, and Gregory S of PEt3 yields the dark green hafnium(II1)- hafnium(II1) dimer HfiC&(PEt,)d. The X-ray crystal structure shows that moleculesof Hf2C&(PEt3)4consistof two octahedral hafnium centers that are connected

  11. Flame retardancy mechanisms of aluminium phosphinate in combination with melamine polyphosphate and zinc borate in glass-fibre reinforced polyamide 6,6

    Microsoft Academic Search

    Ulrike Braun; Bernhard Schartel; Mario A. Fichera; Christian Jäger

    2007-01-01

    The fire retardancy mechanisms of aluminium diethylphosphinate in combination with melamine polyphosphate and zinc borate was analysed in glass-fibre reinforced polyamide 6,6. The influence of phosphorus compounds on the polyamide decomposition pathways was characterized using thermal analysis (TG), evolved gas analysis (TG–FTIR), and FTIR–ATR analysis of the residue. The Lewis acid–base interactions between the flame retardants, the amide unit, and

  12. Origin of n-type conduction at the interface between epitaxial-grown layer and InP substrate and its suppression by heating in phosphine atmosphere

    Microsoft Academic Search

    Hideto Ishikawa; Shiro Miwa; Toshiyuki Maruyama; Mikio Kamada

    1992-01-01

    The origin of unintentionally introduced n-type conduction at the interface of epitaxially grown layer-InP substrate is identified. From the relation between the sheet carrier concentration and the etching depth, an n-type conducting layer was found at the epitaxial layer-substrate interface. The sheet carrier concentration and the sheet Si concentration at the surface of the InP substrate, which was obtained by

  13. Effect of phosphine plasma treatment on protection from Si passivation in AlInAs\\/InGaAs HEMT due to F atoms

    Microsoft Academic Search

    K. Yamamoto; N. Fujita; S. Nakajima; T. Sugino

    2001-01-01

    A process technology to suppress diffusing fluorine (F) atoms into the AlInAs layer at elevated temperature is investigated using AlInAs\\/InGaAs HEMT wafers grown on InP substrates. Removal of F atoms adsorbed on the AlInAs surface and formation of a barrier layer to suppress F diffusion are attempted by a plasma process. It is demonstrated by SIMS measurements that diffusion of

  14. Synthesis and Activity in Ring-Closing Metathesis of Phosphine and NHC-Containing Ruthenium-Indenylidene (Bis)Pyridine Complexes

    NASA Astrophysics Data System (ADS)

    Clavier, Herve; Nolan, Steven P.

    : The reactions of Cl2-Ru-(3-phenylindenylidene) complexes with excess pyridine lead to new ruthenium (Ru)-based bis(pyridine) adducts in good yield. These thermally robust catalysts have been tested in ring-closing metathesis (RCM). In spite of promising initiation rates, only moderate to good activities have been observed in kinetic studies on several substrates.

  15. Measurement of Homocysteine and Other Aminothiols in Plasma: Advantages of Using Tris(2-carboxyethyl)phosphine as Reductant Compared with Tri-n-butylphosphine

    Microsoft Academic Search

    Jakub Krijt; Martina Vackova

    Background: Aminothiols have been implicated in the pathogenesis of arteriosclerosis, and reliable methods are needed to determine their concentrations in body fluids. We present a comparison of two analytical meth- ods and focus on the reduction of low-molecular weight and protein-mixed disulfides of homocysteine, cysteine, cysteinyl-glycine, and glutathione. Methods: The plasma total aminothiol profile was de- termined by HPLC with

  16. Determination of Ascorbic Acid and Dehydroascorbic Acid in Biological Samples by High-Performance Liquid Chromatography Using Subtraction Methods: Reliable Reduction with Tris[2-carboxyethyl]phosphine Hydrochloride

    Microsoft Academic Search

    Jens Lykkesfeldt

    2000-01-01

    Determination of dehydroascorbic acid in biological samples most commonly involves indirect measurement. The concentration is calculated by subtraction of the measured ascorbic acid concentration from that of total ascorbic acid analyzed after reduction of the dehydroascorbic acid present; a methodology also referred to as subtraction methods. Consequently, successful determination of dehydroascorbic acid is dependent on proper sample handling, quantitative reduction

  17. The Economic Impact from the Extension of Unemployment Insurance to Texas Agriculture. 

    E-print Network

    Fritsch, Conrad F.; Ruesink, David C.; Nergart, Karen J.

    1974-01-01

    Understanding the adsorption of phosphine oxides on silica surfaces has a threefold incentive. (a) Efficiently removing phosphine oxides from reaction mixtures is crucial after many synthetic procedures, for example the ...

  18. Pd-catalyzed addition–carbocyclization of ?,?-diynes with H–P(O)R 2 compounds

    Microsoft Academic Search

    Jun Kanada; Koh-ichiro Yamashita; Satish Kumar Nune; Masato Tanaka

    2009-01-01

    Chelating phosphines are much higher performing than mono-dentate phosphines in palladium-catalyzed reaction of ?,?-diynes with HP(O)R1R2 (R1,R2=Ph, alkoxy) to afford (E)-3-(phosphorylmethylene)-2-methylcyclopentenes.

  19. Highly convergent synthesis of chiral bicyclophosphinates by domino hydrophosphinylation/Michael/Michael reaction.

    PubMed

    Fourgeaud, Pierre; Daydé, Bénédicte; Volle, Jean-Noël; Vors, Jean-Pierre; Van der Lee, Arie; Pirat, Jean-Luc; Virieux, David

    2011-10-01

    Diastereoselective domino reactions of iminoalcohols and allenyl H-phosphinates produce chiral phosphorus bicycles in a regio- and stereoselective fashion. A predictive model for diastereoselection is used for these new chiral phosphinic esters. PMID:21888337

  20. Protein Sequencing by Matrix-Assisted Laser Desorption Ionization–Postsource Decay–Mass Spectrometry Analysis of the N-Tris(2,4,6-trimethoxyphenyl)phosphine-Acetylated Tryptic Digests

    Microsoft Academic Search

    Zhi-Heng Huang; Tunli Shen; Jiang Wu; Douglas A. Gage; J. Throck Watson

    1999-01-01

    We have recently reported a simple procedure by which low picomole quantities of peptides can be modified to the correspondingN-Tris(2,4,6-trimethoxyphenyl)phosphonium-acetyl (TMPP-Ac) derivatives (Z. H Huang, J. Wu, D. A. Gage, and J. T. Watson,Anal. Chem.69, 137–144, 1997). This modification significantly facilitates sequence interpretation by providing exclusively N-terminal product ions (mainly a-type ions) in the fast-atom bombardment–MS\\/MS and matrix-assisted laser desorption

  1. End-on and side-on ?-acid ligand adducts of gold(I): carbonyl, cyanide, isocyanide, and cyclooctyne gold(I) complexes supported by N-heterocyclic carbenes and phosphines.

    PubMed

    Celik, Mehmet Ali; Dash, Chandrakanta; Adiraju, Venkata A K; Das, Animesh; Yousufuddin, Muhammed; Frenking, Gernot; Dias, H V Rasika

    2013-01-18

    N-heterocyclic carbene ligand SIDipp (SIDipp = 1,3-bis(2,6-diisopropylphenyl)imidazolin-2-ylidene) and trimesitylphosphine ligand have been used in the synthesis of gold(I) cyanide, t-butylisocyanide, and cyclooctyne complexes (SIDipp)Au(CN) (3), (Mes(3)P)Au(CN) (4), [(Mes(3)P)(2)Au][Au(CN)(2)] (5), [(SIDipp)Au(CN(t)Bu)][SbF(6)] ([6][SbF(6)]), [(SIDipp)Au(cyclooctyne)][SbF(6)] ([8][SbF(6)]), and [(Mes(3)P)Au(cyclooctyne)][SbF(6)] ([9][SbF(6)]). A detailed computational study has been carried out on these and the related gold(I) carbonyl adducts [(SIDipp)Au(CO)][SbF(6)] ([1][SbF(6)]), [(Mes(3)P)Au(CO)][SbF(6)] ([2][SbF(6)]), and [(Mes(3)P)Au(CN(t)Bu)](+) ([7](+)). X-ray crystal structures of 3, 5, [6][SbF(6)], [8][SbF(6)], and [9][SbF(6)] revealed that they feature linear gold sites. Experimental and computational data show that the changes in ?-acid ligand on (SIDipp)Au(+) from CO, CN(-), CN(t)Bu, cyclooctyne as in [1](+), 3, [6](+), and [8](+) did not lead to large changes in the Au-C(carbene) bond distances. A similar phenomenon was also observed in Au-P distance in complexes [2](+), 4, [7](+), and [9](+) bearing trimesitylphosphine. Computational data show that the Au-L bonds of "naked" [Au-L](+) or SIDipp and Mes(3)P supported [Au-L](+) (L = CO, CN(-), CN(t)Bu to cyclooctyne) have higher electrostatic character than covalent character. The Au?L ?-donation and Au?L ?-back-donation contribute to the orbital term with the former being the dominant component, but the latter is not negligible. In the Au-CO adducts [1](+)and [2](+), the cationic gold center causes the polarization of the C-O ? and ? orbitals toward the carbon end making the coefficients at the two atoms more equal which is mainly responsible for the large blue shift in the CO stretching frequency. The SIDipp and Mes(3)P supported gold(I) complexes of cyanide and isocyanide also exhibit a significant blue shift in ?(CN) compared to that of the free ligands. Calculated results for Au(CO)Cl and Au(CF(3))CO suggest that the experimentally observed blue shift in ?(CO) of these compounds may at least partly be caused by intermolecular forces. PMID:23273108

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

    PubMed

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

    2015-01-21

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

  3. Bis(acetylacetonato)ruthenium(II) complexes containing bulky tertiary phosphines. Formation and redox behaviour of Ru(acac) 2 (PR 3) (R = i Pr, Cy) complexes with ethene, carbon monoxide, and bridging dinitrogen

    Microsoft Academic Search

    Martin A. Bennett; Matthew J. Byrnes; Guandolina Chung; Alison J. Edwards; Anthony C. Willis

    2005-01-01

    Reaction of cis-[Ru(acac)2(?2-C8H14)2] (1) (acac=acetylacetonato) with two equivalents of PiPr3 in THF at ?25 °C gives trans-[Ru(acac)2(PiPr3)2], trans-3, which rapidly isomerizes to cis-3 at room temperature. The poorly soluble complex [Ru(acac)2(PCy3)2] (4), which is isolated similarly from cis-[Ru(acac)2(?2-C2H4)2] (2) and PCy3, appears to exist in the cis-configuration in solution according to NMR data, although an X-ray diffraction study of a

  4. Inhibition of NF ?B–DNA binding by mercuric ion: utility of the non-thiol reductant, tris(2-carboxyethyl)phosphine hydrochloride (TCEP), on detection of impaired NF ?B–DNA binding by thiol-directed agents

    Microsoft Academic Search

    F. J Dieguez-Acuña; J. S Woods

    2000-01-01

    Mercuric ion (Hg2+), a potent thiol inhibitor, prevents expression of nuclear factor ?B (NF-?B) by mercaptide bond formation with a critical cysteine moiety (cys62) on the p50 subunit required for DNA binding. NF-?B–DNA binding is typically measured in reaction mixtures in which dithiothreitol (DTT) or other thiol reductants are used to maintain cys62 in the reduced state. However, the presence

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

    Microsoft Academic Search

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

    2002-01-01

    Fluorescence labeling of proteins has become increasingly important since fluorescent techniques like FRET and fluorescence polarization are now commonly used in protein binding studies, proteomics, and for high-throughput screening in drug discovery. In our efforts to study the binding of the ??-subunit from Escherichia coli RNA polymerase (RNAP) to ?70, we synthesized a fluorescent-labeled ??-fragment (residues 100–309) in a very

  6. NaBH/sub 4/ reduction of CO in the cationic iron carbonyl complexes (C/sub 5/Me/sub 5/Fe(CO)/sub 2/L)/sup +/PF/sub 6//sup /minus// (L = CO or phosphine)

    SciTech Connect

    Lapinte, C.; Catheline, D.; Astruc, D.

    1988-08-01

    C-C bond formations are relevant to the Fischer-Tropsch and related processes such as the hydroformylation of formaldehyde to glycolaldehyde, a precursor of ethylene glycol. The Fischer-Tropsch sequence that consists of the reduction of CO to methyl followed by C-C bond formation and reduction to alkanes is long-known in the Fp series from the work of Atwood. Cutler's studies consisted of the transformation of CpFe/sup +/(CO)/sub 3/ into a variety of C/sub 2/ organic molecules such as CpFeCH/sub 2/OCH/sub 3/ (eq5). CpFe/sup +/(CO)/sub 3/ NaBH/sub 3/CN /yields/ MeOH CpFe(CO)/sub 2/CH/sub 2/OCH/sub 3/. In 1983, the authors reported (Fp*CO)/sup +/PF/sub 6//sup /minus// (1) was reduced by NaBH/sub 4/ to Fp*CH/sub 2/OH (3), Fp*CH/sub 3/ (4), or Fp*H (5) depending on the solvent. They report here full details of the reduction of (Fp*L)/sup +/PF/sub 6//sup /minus// (L = CO (1), P-n-Bu/sub 3/ (9a), PMe/sub 5/ (9b), or PPh/sub 3/ (9c)) by NaBH/sub 4/ and that of 1 by the transition-metal hydrides 5 and H/sub 4/Mo(dppe)/sub 2/ (8). The reactivities of the hydride reduction products especially those of the formyl and hydroxymethyl complexes are discussed. Several aspects of this work have been published as preliminary communications.

  7. 3220 FR.01 Restricted Items Approval Request INSTRUCTIONS

    E-print Network

    tetroxide Phosgene Phosphine Cyanide compounds Ethylene oxide Perchloric acid Alkali Metals Barium Lithium Germane Berryllium Cesium Liquid scintillation counters (LSC) Lead aprons Lasers - Class IIIb

  8. Synthesis, characterization, and reactivity studies of iridium complexes bearing the ligand diphenylphosphidoboratabenzene

    E-print Network

    Arizpe, Luis (Luis Alfredo)

    2011-01-01

    The synthesis, structure, and reactivity properties of three iridium square planar complexes bearing the anionic phosphine ligand diphenylphosphidoboratabenzene (DPB) are described. Reactivity studies show a rate enhancement ...

  9. 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.…

  10. Conjugate and method for forming aminomethyl phosphorus conjugates

    DOEpatents

    Katti, Kattesh V. (Columbia, MO); Berning, Douglas E. (Columbia, MO); Volkert, Wynn A. (Columbia, MO); Ketring, Alan R. (Columbia, MO); Churchill, Robert (Columbia, MO)

    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.

  11. Subscriber access provided by DALIAN INST OF CHEM PHYSICS The Journal of Physical Chemistry C is published by the American Chemical

    E-print Network

    Bao, Xinhe

    Structure, Activity, and Stability of Triphenyl Phosphine-Modified Rh/SBA-15 Catalyst for Hydroformylation of Triphenyl Phosphine-Modified Rh/SBA-15 Catalyst for Hydroformylation of Propene: A High-Resolution Solid in the hydroformylation of propene. Heterogeneous PPh3-Rh(CO)/SBA-15 catalyst showed much higher activity and stability

  12. 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.

  13. Brønsted acid-catalyzed intramolecular nucleophilic substitution of the hydroxyl group in stereogenic alcohols with chirality transfer.

    PubMed

    Bunrit, Anon; Dahlstrand, Christian; Olsson, Sandra K; Srifa, Pemikar; Huang, Genping; Orthaber, Andreas; Sjöberg, Per J R; Biswas, Srijit; Himo, Fahmi; Samec, Joseph S M

    2015-04-15

    The hydroxyl group of enantioenriched benzyl, propargyl, allyl, and alkyl alcohols has been intramolecularly displaced by uncharged O-, N-, and S-centered nucleophiles to yield enantioenriched tetrahydrofuran, pyrrolidine, and tetrahydrothiophene derivatives with phosphinic acid catalysis. The five-membered heterocyclic products are generated in good to excellent yields, with high degree of chirality transfer, and water as the only side-product. Racemization experiments show that phosphinic acid does not promote SN1 reactivity. Density functional theory calculations corroborate a reaction pathway where the phosphinic acid operates as a bifunctional catalyst in the intramolecular substitution reaction. In this mechanism, the acidic proton of the phosphinic acid protonates the hydroxyl group, enhancing the leaving group ability. Simultaneously, the oxo group of phosphinic acid operates as a base abstracting the nucleophilic proton and thus enhancing the nucleophilicity. This reaction will open up new atom efficient techniques that enable alcohols to be used as nucleofuges in substitution reactions in the future. PMID:25803790

  14. 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.

  15. Methods for removing contaminant matter from a porous material

    DOEpatents

    Fox, Robert V. (Idaho Falls, ID) [Idaho Falls, ID; Avci, Recep (Bozeman, MT) [Bozeman, MT; Groenewold, Gary S. (Idaho Falls, ID) [Idaho Falls, ID

    2010-11-16

    Methods of removing contaminant matter from porous materials include applying a polymer material to a contaminated surface, irradiating the contaminated surface to cause redistribution of contaminant matter, and removing at least a portion of the polymer material from the surface. Systems for decontaminating a contaminated structure comprising porous material include a radiation device configured to emit electromagnetic radiation toward a surface of a structure, and at least one spray device configured to apply a capture material onto the surface of the structure. Polymer materials that can be used in such methods and systems include polyphosphazine-based polymer materials having polyphosphazine backbone segments and side chain groups that include selected functional groups. The selected functional groups may include iminos, oximes, carboxylates, sulfonates, .beta.-diketones, phosphine sulfides, phosphates, phosphites, phosphonates, phosphinates, phosphine oxides, monothio phosphinic acids, and dithio phosphinic acids.

  16. Systems and strippable coatings for decontaminating structures that include porous material

    DOEpatents

    Fox, Robert V. (Idaho Falls, ID); Avci, Recep (Bozeman, MT); Groenewold, Gary S. (Idaho Falls, ID)

    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.

  17. Umpolung of methylenephosphonium ions in their manganese half-sandwich complexes and application to the synthesis of chiral phosphorus-containing ligand scaffolds.

    PubMed

    Valyaev, Dmitry A; Filippov, Oleg A; Lugan, Noël; Lavigne, Guy; Ustynyuk, Nikolai A

    2015-05-18

    Half-sandwich manganese methylenephosphonium complexes [Cp(CO)2Mn(?(2)-R2P=C(H)Ph)]BF4 were obtained in high yield through a straightforward reaction sequence involving a classical Fischer-type manganese complex and a secondary phosphine as key starting materials. The addition of various nucleophiles (Nu) to these species took place regioselectively at the double-bonded carbon center of the coordinated methylenephosphonium ligand R2P(+)=C(H)Ph to produce the corresponding chiral phosphine complexes [Cp(CO)2Mn(?(1)-R2P-C(H)(Ph)Nu)], from which the phosphines were ultimately recovered as free entities upon simple irradiation with visible light. The synthetic potential of this umpolung approach is illustrated herein by the preparation of novel chiral pincer-type phosphine-NHC-phosphine ligand architectures. PMID:25832414

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

    PubMed

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

    2015-01-01

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

  19. Rhodium-Catalyzed Asymmetric Intramolecular Hydroamination of Unactivated Alkenes

    E-print Network

    Shen, Xiaoqiang

    One for the Rh(oad): The first rhodium-catalyzed asymmetric intramolecular hydroamination of unactivated olefins was developed by using dialkylbiaryl phosphine ligands (see scheme; cod=1,5-cyclooctadiene, Cy=cyclohexyl). ...

  20. N-Substituted 2-Aminobiphenylpalladium Methanesulfonate Precatalysts and Their Use in C–C and C–N Cross-Couplings

    E-print Network

    Bruno, Nicholas C.

    A series of phosphine-ligated palladium precatalysts based on N-methyl- and N-phenyl-2-aminobiphenyl have been developed. Substitution at the nitrogen center prevents the presence of traces of aminobiphenyls that contain ...

  1. Elastomer-modified phosphorus-containing imide resins

    NASA Technical Reports Server (NTRS)

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

    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.

  2. 78 FR 6274 - Withdrawal of Pesticide Petitions for Residues of Pesticide Chemicals in or on Various Commodities

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-30

    ...225 for residues of phosphine, in or on asparagus; cherimoya; dates, fresh; figs, fresh; globe artichokes; pawpaws; pineapple, water chestnuts and watercress, and for all fresh fruit and vegetable crop groups (including berry and small fruit;...

  3. 76 FR 61647 - Receipt of Several Pesticide Petitions Filed for Residues of Pesticide Chemicals in or on Various...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-05

    ...180 for residues of phosphine, in or on asparagus; cherimoya; dates, fresh; figs, fresh; globe artichokes; pawpaws; pineapple, water chestnuts and watercress, and for all fresh fruit and vegetable crop groups (including berry and small fruit;...

  4. Chemoselective ligation

    DOEpatents

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

    2011-05-10

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

  5. Chemoselective ligation

    DOEpatents

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

    2011-12-13

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

  6. Chemoselective ligation

    DOEpatents

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

    2010-11-23

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

  7. 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).

  8. Chemoselective ligation

    DOEpatents

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

    2003-05-27

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

  9. Chemoselective ligation

    DOEpatents

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

    2010-02-23

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

  10. Chemoselective ligation

    DOEpatents

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

    2011-04-12

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

  11. Re and (99m)Tc complexes of BodP3--multi-modality imaging probes.

    PubMed

    Davies, Laura H; Kasten, Benjamin B; Benny, Paul D; Arrowsmith, Rory L; Ge, Haobo; Pascu, Sofia I; Botchway, Stan W; Clegg, William; Harrington, Ross W; Higham, Lee J

    2014-12-21

    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

  12. Nickel-Catalyzed Allylic Substitution of Simple Alkenes

    E-print Network

    Matsubara, Ryosuke

    This report describes a nickel-catalyzed allylic substitution process of simple alkenes whereby an important structural motif, a 1,4-diene, was prepared. The key to success is the use of an appropriate nickel–phosphine ...

  13. Studies of Platinum Polyynyl Complexes: Elaboration of Novel "Click" Cycloadducts and Fluorous and Polygon Based Platinum Polyyndiyl Systems 

    E-print Network

    Clough, Melissa Catherine 1985-

    2012-11-13

    complexes featuring fluorous phosphine ligands and (3) click reactions of metal terminal polyynyl complexes and further metallations of the resulting triazole rings. A brief overview is provided in Chapter I. Chapter II details the syntheses of molecular...

  14. Dwell Time Analysis of a Single-Molecule Mechanochemical Reaction Robert Szoszkiewicz,*, Sri Rama Koti Ainavarapu, Arun P. Wiita, Raul Perez-Jimenez,

    E-print Network

    Fernandez, Julio M.

    : tris-(2-carboxyethyl)- phosphine hydrochloride (TCEP) and the enzyme thioredoxin (TRX). A different scale. In the case of TCEP, the logarithmic histogram of dwell times showed a single peak, corresponding

  15. An Improved Synthesis of BrettPhos- and RockPhos-Type Biarylphosphine Ligands

    E-print Network

    Hoshiya, Naoyuki

    Improved processes for the preparation of biphenyl-based phosphine ligands t-BuBrettPhos, RockPhos, and BrettPhos are presented. The new methods, featuring the use of Grignard reagents and catalytic amounts of copper, are ...

  16. Extremely Electron-Rich, Boron-Functionalized, Icosahedral Carborane-Based Phosphinoboranes

    E-print Network

    Spokoyny, Alexander M.

    We have prepared the first examples of B9-connected trivalent aryl and alkyl phosphinoborane species via Pd-catalyzed phosphination of 9-iodo-meta-carborane. Our studies highlight the unique electronic features of the ...

  17. 76 FR 34700 - Protection of Stratospheric Ozone: Request for Methyl Bromide Critical Use Exemption Applications...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-14

    ...producers when converting to alternatives such as: sulfuryl fluoride and phosphine. If relevant, the applicant should also include...producers when converting to alternatives such as: sulfuryl fluoride, micro-sanitation, and heat. If relevant, the...

  18. Flame retardance of epoxy acrylate resin modified with phosphorus containing compounds

    Microsoft Academic Search

    M. Vezir Kahraman; Nilhan Kayaman-Apohan; Nergis Arsu; Atilla Güngör

    2004-01-01

    In this work, UV-radiation curing of allyldiphenyl phosphine oxide (ADPPO) and 4,4?-bis(allyloxyphenyl) phenyl phosphine oxide (DAPPO) monomers with epoxy acrylate resin in the presence of a photoinitiator was studied and their flame-retardant performance compared with pure epoxy acrylate film. The structures of allyl functional phosphorus compounds were characterized by FT-IR, 1H NMR, 13C NMR and all spectra were consistent with

  19. Aqueous Partitioning of Minor Actinides by Different Processes

    Microsoft Academic Search

    Seraj A. Ansari; Priyanath Pathak; Prashanta K. Mohapatra; Vijay K. Manchanda

    2011-01-01

    Actinide partitioning is a proposed strategy for effective mitigation of the long-term hazards associated with high-level waste (HLW). Octyl-(phenyl)–N,N-diisobutyl carbamoyl methyl phosphine oxide (CMPO) and diphenyl–N,N-diisobutyl carbamoyl methyl phosphine oxide (D?CMPO) are amongst the promising extractants extensively studied since the 1980s for actinide partitioning from wastes of different origin. During the last two decades, substituted malonamide extractants such as N,N'-dimethyl-N,N'-dibutyl

  20. Influence of phosphorus valency on thermal behaviour of flame retarded polyurethane foams

    Microsoft Academic Search

    A. Lorenzetti; M. Modesti; S. Besco; D. Hrelja; S. Donadi

    2011-01-01

    This paper reports decomposition\\/pyrolysis studies of polyurethane (PU) rigid foams containing phosphinate, phosphonate or phosphate as flame retardant in order to study the effect of phosphorus oxidation state on their gas and\\/or solid phase action. The flame retardants analyzed were aluminium phosphinate (IPA), dimethylpropanphosphonate (DMPP), triethylphosphate (TEP) and ammonium polyphosphate (APP), which differ in oxidation state and\\/or decomposition temperature. Gases

  1. Metal-Catalyzed Carbon-Carbon Bond Forming Reactions for the Synthesis of Significant Chiral Building Blocks 

    E-print Network

    Bugarin Cervantes, Alejandro

    2011-08-08

    by nucleophilic tertiary amines or phosphines.2 In the seminal report,1 Morita and coworkers reported the first nucleophilic triggered acrylic ?-substitution catalyzed by phosphines. Treatment of acrylonitrile with catalytic amounts of tricyclohexylphosphine... several activated alkenes including alkyl vinyl ketones,5-7 alkyl and aryl acrylates,8-10 acrolien,11,12 allenic esters,13 acrylonitriles,6,14 vinyl sulfones and sulfonates,15,16 as well as vinyl phosphonates17 on reactions with aldehydes at atmospheric...

  2. Synthesis and X-ray Crystal Structure of [2-(Phosphinomethyl)ferrocenyl]diphenylphosphine Francis Labrueb

    E-print Network

    Paris-Sud XI, Université de

    (hydroxymethyl)phosphine as the nucleophile [1]. CH2-NMe2 P(X)Ph2 Fe CH2-NMe2 Fe CH2-NMe3 P(X)Ph2 Fe 3, X = lone pair refs. 5, 6 ii. H2O2, Me1 Synthesis and X-ray Crystal Structure of [2-(Phosphinomethyl)ferrocenyl]diphenylphosphine Francis on the pioneering work above, we envisioned the synthesis of the analogous primary phosphine 2 which bears

  3. Metal Phosphorus Complexes as Antitumor Agents

    Microsoft Academic Search

    Alexey A. Nazarov; Paul J. Dyson

    \\u000a Phosphorus-based ligands are an extremely important class of ligand and they have found many applications, especially in homogeneous\\u000a catalysis. In addition, a phosphine ligand is found in a gold drug used to treat rheumatoid arthritis. Since metal compounds\\u000a are also widely used to treat cancer many studies on the anticancer activity of metal–phosphine complexes have been conducted.\\u000a In this chapter

  4. UPTAKE OF GOLD FROM HYDROCHLORIC ACID SOLUTIONS BY POLYMERIC RESINS BEARING VARIOUS PHOSPHORUS CONTAINING LIGANDS

    Microsoft Academic Search

    Andrzej W. Trochimczuk

    2002-01-01

    Polymeric resins with phosphonate esters, phosphinate esters, and phosphine oxide ligands are synthesized via Arbusov reaction, characterized and used in the removal of Au(III) from hydrochloric acid solutions. It is found that phosphonate ethyl and butyl esters are able to adsorb as much as 100–120 mg Au\\/g of the resin. Affinity of these two resins towards gold, measured as the logarithm

  5. X-ray diffraction investigation of crystals of bis(nitrosodicyano-methanido)tetrakis(tris(dimethylamino)phosphine oxide)ytterbium(III) nitrosodicyanomethanide, (Yb/ONC(CN/sub 2/)//sub 2//OP(N(CH/sub 3/)/sub 2/)/sub 2///sub 4/)ONC(CN)/sub 2/

    SciTech Connect

    Zub, Yu.L.; Sadikov, G.G.; Skopenko, V.V.; Porai-Koshits, M.A.; Nikolaev, V.P.

    1986-02-01

    The crystal structure of (Yb/ONC(CN)/sub 2///sub 2//OP(N(CH/sub 3/)/sub 2/)/sub 3///sub 4/)ONC(CN)/sub 2/ has been determined by x-ray diffraction analysis (diffractomter, Mo K..cap alpha.. radiation, 4396 reflections, isotropic-anisotropic least-squares method in the full-matrix variant to R = 0.081). The parameters of the monoclinic cell are: a = 11.440(3), b = 14.728(3), c = 34.912(9) A, ..beta.. = 97.53(2)/sup 0/, V = 5832(3) A/sup 3/, d(pycn) = 1.30(1), d(x-ray) = 1.335 g/cm/sup 3/, Z = 4, space group P2/sub 1//c. The structural elements of the crystals are the (Yb/ONC(CN)/sub 2///sub 2//OP(N(CH/sub 3/)/sub 2/)/sub 3///sub 4/)/sup +/ complex cation and the outer-sphere ONC(CN)/sub 2/ group, which randomly occupies two positions. The coordination number of ytterbium is 6 (all the ligands are coordinated as monodentate ligands by means of an oxygen atom), and the coordination polyhedron is an asymmetrically elongated tetragonal bipyramid, whose axial vertices are occupied by the oxygen atoms of the ..pi..-acid ligands. The mean length of the Yb-O(OP(N(CH/sub 3/)/sub 2/)/sub 3/) bonds is 2.197(11) A. The distances from the Yb atom to the oxygen atoms of the ONC(CN)/sub 2/ groups are equal to 2.233(15) and 2.315(18) A. A special feature of the complex cation is the presence of a fourth-order inversion pseudoaxis. A discussion of the structure of the coordination polyhedron and of the phosphoryl and nitrosodicyanomethanide ligands has been conducted with the aid of literature data.

  6. Phosphine complexes of zirconium and hafnium. Synthesis, structure, and fluxional behavior of the trimelthyl derivatives MMe{sub 3}[N(SiMe{sub 2}CH{sub 2}PR{sub 2}){sub 2}] (R = Me, Pr{sup 1}, Bu{sup t}). Evidence for a bicapped-tetrahedral geometry

    SciTech Connect

    Fryzuk, M.D.; Carter, A.; Rettig, S.J. [Univ. of British Columbia, Vancouver, British Columbia (Canada)

    1992-01-01

    The addition of 3 equiv of methyl Grignard (MeMgCl) to the amidodiphosphine derivatives MCl{sub 3} [N-(SiMe{sub 2}CH{sub 2}PR{sub 2}){sub 2}] (M = Zr, Hf; R=Me, Pr{sup i}, Bu{sup t}) generates the corresponding trimethyl complexes MMe{sub 3}[N-(SiMe{sub 2}CH{sub 2}PR{sub 2}){sub 2}]. The solution structures and fluxional behavior of these molecules along with the X-ray structure of HfMe{sub 3}[N(SiMe{sub 2}CH{sub 2}PMe{sub 2}){sub 2}] are presented. 32 refs., 1 fig., 4 tabs.

  7. Hydrido thiolato and thiolato complexes of ruthenium(II) carbonyl phosphines. [cis,cis,trans-RuH(SR)(CO) sub 2 L sub 2 , cis,cis,trans-RuH(SR) sub 2 (CO) sub 2 L sub 2 where R = aryl and L = triphenylphosphine

    SciTech Connect

    Jessop, P.G.; Rettig, S.J.; Chungli Lee; James, B.R. (Univ. of British Columbia, Vancouver (Canada))

    1991-11-27

    Oxidative addition of RSH (R = H, alkyl, aryl) or RSSR (R = aryl) to Ru(CO){sub 2}L{sub 3} (L = PPh{sub 3}, 1) yields respectively cct-RuH(SR)(CO){sub 2L}{sub 2} (type 2) (cct = cis, cis, trans) or cct-Ru(SR){sub 2}(CO){sub 2}L{sub 2} (type 3); a hydrido selenolate species is made similarly using PhSeH. Methods for in situ formation of corresponding mixed bis(thiolate) species are also given. 1 is generally unreactive toward thioethers, although with propylene sulfide cct-Ru({eta}{sup 2}-S{sub 2}) (CO){sub 2}L{sub 2} is produced. Metathesis reaction of cct-RuCl{sub 2}(CO){sub 2}L{sub 2} with NaSR salts yield 3 (R = aryl) or, when R = Et, cct-RuCl(SEt)(CO){sub 2}L{sub 2} or (L(CO){sub 2}Ru({mu}{sub 3}-SEt)Na(THF)){sub 2} (4), depending on reaction conditions. The complexes are characterized by IR spectroscopy, {sup 1}H, {sup 31}P, and, in some cases, {sup 13}C NMR spectroscopy, and for 2g and 3g(R = SC{sub 6}H{sub 4}pMe) and 4, X-ray crystallography. All three complexes crystallized in the space group P {bar 1} 1. 4 has an unprecedented network of transition-metal and alkali-metal ions bridged by thiolate ligands: four thiolates bridge one Ru and one Na, and two thiolates bridge one Ru and two Na atoms. The geometries at Ru and Na are close to octahedral and square pyramidal respectively. Trends are noted for the {sup 1}H NMR shifts and {sup 2}J{sub PH} values for the hydride in 2, and an additivity rule formulated for the {sup 31}P shift within the cct-Ru(SR)(SR')(CO){sub 2}(PPh{sub 3}){sub 2} species. Limited kinetic data suggest that the oxidative addition reactions to 1 probably proceed via a nonradical process, following dissociation of a PPh{sub 3} ligand.

  8. Synthesis of low color, atomic oxygen resistant polyimides

    NASA Technical Reports Server (NTRS)

    MacInnes, Dave

    1995-01-01

    The purpose of this project was to develop low color, atomic oxygen resistant polyimides for potential applications on spacecraft in low earth orbit. The material is needed in order to protect satellites and spacecraft from the gases and radiation found at those altitudes. Phosphorous containing polyimides have been shown to be especially resistant to corrosion and weight loss under oxygen plasma. Unfortunately the color of these phosphorous containing polyimides is still too high for them to be good heat insulators. While they are not as effective as teflon, the current material of choice. polyimides are much less dense than teflon and would be especially valuable if they could be made with low color. The approach taken was to synthesize a monomer which would contain the elements needed for giving the final polyimide its desired properties. In particular the monomer should incorporate phosphine or phosphine oxides and have bulky side groups to block any color forming charge transfer structures. The target molecule, 3,5-di-(trifluoromethylphenyl)-bis(3-aminophenyl) phosphine oxide, (containing both a phosphine oxide group and a bulky ditrifluoromethylphenyl group) was synthesized via three reactions in overall yield of 21 percent. In addition, a model compound, bis(3-phenylamine) phenyl phosphine oxide, was synthesized two different ways in order to establish the conditions for the nitration of phosphine oxides and their reduction to the amine. Finally, a trisubstituted phosphine oxide was synthesized. In all, seven phosphorus containing organic compounds were synthesized, purified and characterized. The model compound was reacted with oxydiphthalic anhydride to form a polyamic acid with inherent viscosity of 0.34. This material was cast into a film and heated, forming a normally colored fairly strong polyimide with a Tg of 240 C. The target compound was reacted with 6-fluorodiphthalic anhydride to give a polyamic acid with inherent viscosity of 0.19 and cast to give a heavily cracked colored film with a Tg of 230 C.

  9. Real-Time Bioluminescence Imaging of Glycans on Live Cells

    PubMed Central

    2010-01-01

    Cell-surface glycans are attractive targets for molecule imaging due to their reflection of cellular processes associated with development and disease progression. In this paper, we describe the design, synthesis, and biological application of a new phosphine probe for real-time imaging of cell-surface glycans using bioluminescence. To accomplish this goal, we took advantage of the bioorthogonal chemical reporter technique. This strategy uses a two-step labeling procedure in which an unnatural sugar analogue containing a functional handle is (1) incorporated into sugar-bearing proteins via the cell’s own biosynthetic machinery and then (2) detected with an exogenously added probe. We designed phosphine?luciferin reagent 1 to activate bioluminescence in response to Staudinger ligation with azide-labeled glycans. We chose to use a phosphine probe because, despite their slow reaction kinetics, they remain the best-performing reagents for tagging azidosugars in mice. Given the sensitivity and negligible background provided by bioluminescence imaging (BLI), we reasoned that 1 might be able to overcome some of the limitations encountered with fluorescent phosphine probes. In this work, we synthesized the first phosphine?luciferin probe for use in real-time BLI and demonstrated that azide-labeled cell-surface glycans can be imaged with 1 using concentrations as low as single digit nanomolar and times as little as 5 min, a feat that cannot be matched by any previous fluorescent phosphine probes. Even though we have only demonstrated its use in visualizing glycans, it can be envisioned that this probe could also be used for bioluminescence imaging of any azide-containing biomolecule, such as proteins and lipids, since azides have been previously incorporated into these molecules. The phosphine?luciferin probe is therefore poised for many applications in real-time imaging in cells and whole animals. These studies are currently in progress in our laboratory. PMID:20527879

  10. PhPMe 2 ligand substitution in the tetracobalt cluster Co 4 (CO) 10 (? 4 PPh) 2 : X-ray diffraction structure of Co 4 (CO) 8 (PPhMe 2 ) 2 (? 4 PPh) 2

    Microsoft Academic Search

    William H. Watson; Ante Nagl; Ming-Jaw Don; Michael G. Richmond

    1996-01-01

    The thermal substitution chemistry of the tetracobalt cluster Co4(CO)10(?4-PPh)2 with the phosphine ligand PhPMe2 (2.5 equiv) has been explored and found to afford the bis(phosphine)-substituted cluster Co4(CO)8(PPhMe2)2(?4-PPh)2 as the major reaction product. The regiochemistry and stereoselectivity exhibited by the two phosphine ligands in Co4(CO)8(PPhMe2)2(?4-PPh)2 have been unambiguously established by X-diffraction analysis as having a 1,3-cis orientation. Co4(CO)8(PPhMe2)2(?4-PPh)2 crystallizes in the

  11. 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.

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

    PubMed

    Wang, Qin; Guo, Cai-Hong; Ren, Ying; Wu, Hai-Shun

    2015-05-01

    The insertion of CO2 into the (PSiP)palladium-allyl bond has been investigated using DFT. Three possible modes of CO2 insertion into (PSiP)Pd-allyl bond have been calculated, that is, direct 1.2-insertion mode, metallo-ene mode, and SE2 mode. The metallo-ene mode is the most favorable via the six-membered ring transition state. The results of calculations are consistent with the regioselectivity observed experimentally. The steric and electronic effects of different phosphine substituents have been evaluated by ONIOM and energy decomposition analysis (EDA) methods. For the phosphine substituents P(i-Pr)2 and PPh2, the contribution of electronic effect is greater than that of steric effect for the CO2 insertion into (PSiP)Pd-allyl bond; while for the phosphine substituent PMe2, the contribution of steric effect is slightly greater than that of electronic effect. PMID:25893517

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

    DOEpatents

    Ramprasad, D.; Waller, F.J.

    1999-04-06

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

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

    DOEpatents

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

    1999-01-01

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

  15. C-P bond-forming reactions via C-O/P-H cross-coupling catalyzed by nickel.

    PubMed

    Yang, Jia; Chen, Tieqiao; Han, Li-Biao

    2015-02-11

    The first Ni-catalyzed C-O/P-H cross-coupling producing organophosphorus compounds is disclosed. This method features wide generality in regard to both C-O and P-H compounds: for C-O compounds, the readily available alcohol derivatives of aryl, alkenyl, benzyl, and allyl are applicable, and for P-H compounds, both >P(V)(O)H compounds (secondary phosphine oxide, H-phosphinate, and H-phosphonate) and hydrogen phosphines (>P(III)H) can be used as the substrates. Thus, a variety of valuable C(sp(2))-P and C(sp(3))-P compounds can be readily obtained in good to excellent yields by this new strategy. PMID:25629169

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

    DOEpatents

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

    2001-01-01

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

  17. Novel growth technologies for in situ formation of semiconductor quantum wire structures

    NASA Astrophysics Data System (ADS)

    Denbaars, S. P.

    Novel growth technologies were developed for low dimensional quantum materials and devices. Non-hydride MOCVD and use of strain to produce InP quantum dots have been achieved. This ONR contract was key to our development of the less hazardous novel non-hydride sources, tertiary butyl arsine (TBA) and tertiary butyl phosphine (TBP) for the growth on InP based electronic devices. Indium Phosphide channel JFET were fabricated by MOCVD using tertiary butyl phosphine (TBP) as the alternative source for phosphine for the first time. We have developed the Stranski-Krastanow (SK) growth mode for the in-situ formation of InP quantum dots. It has been observed that many strained systems exhibit Stranski-Krastanow growth, where the epitaxy initiates in two dimensions but transforms to three dimensions with the formation of dislocations in response to the energetics and kinetics of the layer.

  18. Evolution of hydroformylation chemistry

    SciTech Connect

    Slaugh, L.H. [Shell Development Co., Houston, TX (United States)

    1995-12-01

    A new generation of hydroformylation catalysts was discovered in 1960 at Shell Development Company which dramatically altered the chemistry of producing industrially important alcohols from synthesis gas (CO/H{sub 2}) and olefins. These new homogeneous catalysts were obtained via the use of auxiliary tertiary phosphine ligands with the conventional OXO cobalt carbonyl catalyst. This is believed to have been the first historical example illustrating the utility of phosphine ligands to modify the catalytic properties of homogenous catalysts. In contradistinction to the conventional OXO reaction, highly linear alcohols were obtained in a single-step operation with ease of catalyst recycle. Based on this discovery, an industrial process was developed to produce large volume, environmentally friendly detergent alcohols. The chemistry of this process and a comparison with other hydroformylation catalyst systems will be made. Recent results obtained with phosphine-modified cobalt catalysts for the hydroformylation of substrates other than olefins will be presented.

  19. Assessment of the Intermediacy of Arylpalladium Carboxylate Complexes in the Direct Arylation of Benzene: Evidence for C-H Bond Cleavage by "Ligandless" Species

    PubMed Central

    Tan, Yichen; Hartwig, John F.

    2011-01-01

    Palladium-catalyzed direct arylations of benzene have been proposed to occur by the generation of a phosphine-ligated arylpalladium pivalate complex LPd(Ar)(OPiv) and reaction of this complex with benzene. We have isolated an example of the proposed intermediate and evaluated whether this complex reacts with benzene to form the biaryl products of the catalytic process. In contrast to the proposed mechanism, no biaryl product was formed from cleavage of the benzene C-H bond by LPd(Ar)(OPiv). However, reactions of LPd(Ar)OPiv with benzene and additives that displace or consume the phosphine ligand formed the arylated products in good yield, suggesting that a “ligandless” arylpalladium(II) carboxylate complexes undergoes the C-H cleavage step. Consistent with this conclusion, we found that reactions catalyzed by Pd(OAc)2 without ligand occur faster than, and with comparable selectivities to, reactions catalyzed by Pd(OAc)2 and phosphine ligand. PMID:21314146

  20. Coordination Chemistry of Cyclic Disilylated Germylenes and Stannylenes with Group 11 Metals

    PubMed Central

    2014-01-01

    Reactions of Et3P adducts of bissilylated germylenes and stannylenes with gold, silver, and copper cyanides led to cyanogermyl or -stannyl complexes of the respective metals. In the course of the reaction the phosphine moved to the metal, while the cyanide migrated to the low-coordinate group 14 element. The respective gold complexes were found to be monomeric, whereas the silver and copper complexes exhibited a tendency to dimerize in the solid state. Attempts to abstract the phosphine ligand with B(C6F5)3 led only to the formation of adducts with the borane coordinating to the cyanide nitrogen atom. PMID:25550678

  1. Synergistic solvent extraction studies of uranium(VI) using a combination of naphthenic acid and various neutral donors into benzene

    Microsoft Academic Search

    I. Mohanty; J. Murlidhar; V. Chakravortty

    1998-01-01

    The equilibrium extraction behavior of uranium(VI) using a benzene solution containing naphthenic acid either alone or combined\\u000a with one of the adductants viz., diphenyl sulphoxide, dinonyl sulphoxide, tri-n-butyl phosphate, triphenyl phosphine oxide,\\u000a tri-n-octyl phosphine oxide, triphenyl arsine oxide, 2,9 dimethyl 1,10-phenanthroline, 1,10-phenanthroline, 4,7-diphenyl 1,10-phenanthroline,\\u000a 2,2?-bipyridyl and 2,2?-biquinoline is described. The enhancement in the extraction by addition of such neutral adducts

  2. Palladium catalyzed synthesis of allenes and disubstituted benzene from conjugated enynes

    SciTech Connect

    Gevorgyan, V.; Salter, M.; Saito, S.; Yamamoto, Y. [Tohoku Univ., Sendai (Japan)

    1995-12-31

    It has been found that Pd(0) - bidentate phosphine complex effectively catalyses the addition of CN-containing pronucleophiles 2 to conjugated enynes 1 leading with good to quantitative yields to the corresponding allenes 3. The role of nature of substituents in the enynes 1 and pronucleophiles 2, as well as type of bidentate phosphine ligands in the reaction mentioned will be discussed. In the presence of catalytic amounts of Pd(PPh{sub 3}){sub 4}, no addition of 2 to monosubstituted enynes 1 takes place instead dimerization reaction occurs afford 1,4-disubstituted aromatic compounds 4 in good yields.

  3. Crystallographic analysis of transition-state mimics bound to penicillopepsin: phosphorus-containing peptide analogues.

    PubMed

    Fraser, M E; Strynadka, N C; Bartlett, P A; Hanson, J E; James, M N

    1992-06-01

    The molecular structures of three phosphorus-based peptide inhibitors of aspartyl proteinases complexed with penicillopepsin [1, Iva-L-Val-L-Val-StaPOEt [Iva = isovaleryl, StaP = the phosphinic acid analogue of statine [(S)-4-amino-(S)-3-hydroxy-6-methylheptanoic acid] (IvaVVStaPOEt)]; 2, Iva-L-Val-L-Val-L-LeuP-(O)Phe-OMe [LeuP = the phosphinic acid analogue of L-leucine; (O)Phe = L-3-phenyllactic acid; OMe = methyl ester] [Iva VVLP(O)FOMe]; and 3, Cbz-L-Ala-L-Ala-L-LeuP-(O)-Phe-OMe (Cbz = benzyloxycarbonyl) [CbzAALP(O)FOMe

  4. New ruthenium nitrosyl pincer complexes bearing an O2 ligand. Mono-oxygen transfer.

    PubMed

    Fogler, Eran; Efremenko, Irena; Gargir, Moti; Leitus, Gregory; Diskin-Posner, Yael; Ben-David, Yehoshoa; Martin, Jan M L; Milstein, David

    2015-03-01

    We report on Ru((II))(?(2)-O2) nitrosyl pincer complexes that can return to their original Ru(0) state by reaction with mono-oxygen scavengers. Potential intermediates were calculated by density functional theory (DFT) and a mechanism is proposed, revealing a new type of metal-ligand cooperation consisting of activation of the O2 moiety by both the metal center and the NO ligand. Reaction of the Ru(0) nitrosyl complex 1 with O2 quantitatively yielded the crystallographically characterized Ru((II)) (?(2)-O2) nitrosyl complex 2. Reaction of 2 with the mono-oxygen scavengers phosphines or CO gave the Ru(0) complex 1 and phosphine oxides, or the carbonyl complex 3 (1 trapped by CO) and CO2, respectively. Reaction of 2 with 1 equiv of phosphine at room temperature or -40 °C resulted in immediate formation of half an equivalent of 1 and 1 equiv of phosphine oxide, while half an equivalent of 2 remained unchanged. Overnight reaction at room temperature of 2 with excess CO (?3 equiv) resulted in 3 and CO2 gas as the only products. Reaction of 1 with 1 equiv of mono-oxygen source (dioxirane) at -78 °C yielded the Ru((II))(?(2)-O2) complex 2. Similarly, reaction of the Ru(0) dearomatized complex 4 with O2 led to the crystallographicaly characterized Ru((II))(?(2)-O2) complex 5. Further reaction of 5 with mono-oxygen scavengers (phosphines or CO) led to the Ru(0) complex 4 and phosphine oxides or complex 6 (4 trapped by CO) and CO2. When instead only 1 equiv of 5 was reacted with 1 equiv of phosphine at room temperature, immediate formation of half an equivalent of 4 and 1 equiv of phosphine oxide took place, while half an equivalent of 5 remained unchanged. When 5 reacted with an excess of CO (?3 equiv), complex 6 and CO2 gas were the only products obtained. DFT studies indicate a new mode of metal-ligand cooperation involving the nitrosyl ligand in the oxygen transfer process. PMID:25695626

  5. Phosphorus-containing imide resins

    NASA Technical Reports Server (NTRS)

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

    1983-01-01

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

  6. Phosphorus-containing imide resins

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

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

  7. Preparation, thermal properties and flame retardancy of phosphorus- and silicon-containing epoxy resins

    Microsoft Academic Search

    M. Spontón; L. A. Mercado; J. C. Ronda; M. Galià; V. Cádiz

    2008-01-01

    Phosphorus- and silicon-containing epoxy resins were prepared from (2,5-dihydroxyphenyl)diphenyl phosphine oxide (Gly-HPO), diglycidyloxy methylphenyl silane (DGMPS) and 1,4-bis(glycidyloxydimethyl silyl)-benzene (BGDMSB) as epoxy monomers and diaminodiphenylmethane (DDM), bis(3-aminophenyl)methyl phosphine oxide (BAMPO) and bis(4-aminophenoxy)dimethyl silane (APDS) as curing agents. Epoxy resins with different phosphorus and silicon content were obtained. Their thermal, dynamic mechanical and flame retardant properties were evaluated. The high LOI

  8. The biology and control of the lesser grain borer Rhizopertha dominica (Fab.

    E-print Network

    Thomson, Valiavetil

    1966-01-01

    hole it always went to the bottom and turned around so as to face outwards. Other larvae trying to enter were fiercely attacked. Sometimes such attacks resulted in the puncturing of the body wall of the antagonists and resulted in death due to loss... grams phosphine) per ton of maize. The fumigation was carried out in a series of steel bins each with a capacity of 4, 000 bags of maize. Workers who wore rubber gloves suffered no inconveniences from the phosphine during the one and a half hours...

  9. Rhenium polyhydrides stabilized by arsine ligands

    Microsoft Academic Search

    Michael T Costello; Terri A Harris; Richard A Walton

    1996-01-01

    The mixed phosphine-arsine ligand Ph2PCH2CH2AsPh2 (arphos) has been used to stabilize the rhenium polyhydrides Re2H8 (arphos)2 and ReH7 (arphos). The heptahydride is the first example of a compound of the type ReH7L2 which contains a mixed phosphine-arsine donor set. The spectroscopic and electrochemical properties and stabilities of these complexes are described and compared with data for other complexes of the

  10. Zinc Phosphide Poisoning

    PubMed Central

    Do?an, Erdal; Güzel, Abdulmenap; Çiftçi, Taner; Aycan, ?lker; Çetin, Bedri; Kavak, Gönül Ölmez

    2014-01-01

    Zinc phosphide has been used widely as a rodenticide. Upon ingestion, it gets converted to phosphine gas in the body, which is subsequently absorbed into the bloodstream through the stomach and the intestines and gets captured by the liver and the lungs. Phosphine gas produces various metabolic and nonmetabolic toxic effects. Clinical symptoms are circulatory collapse, hypotension, shock symptoms, myocarditis, pericarditis, acute pulmonary edema, and congestive heart failure. In this case presentation, we aim to present the intensive care process and treatment resistance of a patient who ingested zinc phosphide for suicide purposes. PMID:25101186

  11. Extremely Electron-Rich, Boron-Functionalized, Icosahedral Carborane-Based Phosphinoboranes

    PubMed Central

    Spokoyny, Alexander M.; Lewis, Calvin D.; Teverovskiy, Georgiy; Buchwald, Stephen L.

    2012-01-01

    We have prepared the first examples of B9-connected trivalent aryl and alkyl phosphinoborane species via Pd-catalyzed phosphination of 9-iodo-meta-carborane. Our studies highlight the unique electronic features of the B9-connected meta-carboranyl moiety as compared to its C1-based analogue. This work suggests that the B9-functionalized meta-carboranyl substituent in these ligands exhibits more electron-releasing character than any other known carbon-based substituent, ultimately laying the foundation for a new class of phosphine ligands with extremely electron-rich character. PMID:23667288

  12. Mechanistic study of palladium catalyzed S–S and Se–Se bonds addition to alkynes

    Microsoft Academic Search

    Valentine P Ananikov; Michael A Kabeshov; Irina P Beletskaya; Grigory G Aleksandrov; Igor L Eremenko

    2003-01-01

    The mechanistic study of palladium catalyzed S–S and Se–Se bonds addition to alkynes revealed the involvement of dinuclear transition metal complexes in the catalytic cycle. Coordination of alkyne to dinuclear transition metal complex was found to be the rate determining step of the reaction. An unusual phosphine ligand effect increasing the yield of addition reaction was found in the studied

  13. Reduction of nitro compounds by carbon monoxide on palladium complexes

    SciTech Connect

    Min'kov A.I.; Eremenko, N.K.; Merkur'eva, S.E.; Efimov, O.A.

    1986-12-20

    Various types of nitro compounds may be reduced to the corresponding amines by carbon monoxide and water in the presence of palladium acetate and a tertiary aromatic phosphine. A catalytically active complex, (HPd/sub 2/(PPh/sub 3/)/sub 4/(CO)(HSO/sub 4/))/sub n/, was isolated.

  14. Effect of diluents on the extraction of actinides and nitric acid by bidentate organophosphorus compounds

    Microsoft Academic Search

    Rozen

    1986-01-01

    The effect of dilutents on extraction by bidentate organophosphorus compounds (diphosphine dioxides, carbamoyl phosphonates, and phosphine oxides) was studied. Figures show the effect of dilutents on the extraction of americium by TOPO and by carbamoylmethylene phosphonate, and the effect of dilutents on the extraction of nitric acid and americium by carbamoylphosphine oxide. Also shown is the effect of dilutents on

  15. Syntheses and Study of Some New Coordination Polymers Mn (II) with Semiconductor Properties

    Microsoft Academic Search

    I. Rosca; L. Oprea; D. Sutiman; A. Cailean; E. Neagu; M. Vizitiu; D. Sibiescu; G. Apostolescu

    2003-01-01

    In this paper, the synthesis and the study of some coordination polymers of Mn (II) with ligands derived from acids: dinaphtylphosphinic, dinaphtylthiophosphinic and dinaphtyldithiophosphinic are presented. The synthesis was accomplished by refluxing in organic solvents the reactants: acetylacetonate of Mn (II) and one of the respective phosphinic acids. Studies were performed applying the following methods: chemical analysis, gel chromatography: IR-spectroscopy;

  16. 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.

  17. Self-assembled monolayer of organic iodine on a Au surface for attachment of redox-active metal clusters.

    PubMed

    Yu, Ying; Dubey, Manish; Bernasek, Steven L; Dismukes, G Charles

    2007-07-17

    The attachment of a bifunctional iodo-organo-phosphinate compound to gold (Au) surfaces via chemisorption of the iodine atom is described and used to chelate a redox-active metal cluster via the phosphinate group. XPS, AFM, and electrochemical measurements show that (4-iodo-phenyl)phenyl phosphinic acid (IPPA) forms a tightly bound self-assembled monolayer (SAM) on Au surfaces. The surface coverage of an IPPA monolayer on Au was quantified by an electrochemical method and found to be 0.40 +/- 0.03 nmol/cm2, roughly corresponding to 0.4 monolayers. We show that the Au/IPPA SAM, but not the underivatized Au, adsorbs Mn4O4(Ph2PO2)6 from solution by a phosphinate exchange reaction to yield Au/IPPA/Mn4O4(Ph2PO2)5 SAM. The resulting SAM is firmly bound and not removed by sonication, as confirmed by manganese XPS (Mn 2p1/2) and by AFM. Electrochemistry confirms that Mn4O4(Ph2PO2)6 is anchored on the Au/IPPA surface and that redox chemistry can be mediated between the electrode and the surface-attached complex. Mn4O4(Ph2PO2)6 contains the reactive Mn4O46+ cubane core, a redox-active bioinspired catalyst. PMID:17583917

  18. 40 CFR 721.10370 - Phosphonic acid, p-octyl-, lanthanum (3+) salt (2:1).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...Phosphonic acid, p-octyl-, lanthanum (3+) salt (2:1). 721.10370 Section 721...Phosphonic acid, p-octyl-, lanthanum (3+) salt (2:1). (a) Chemical substance...phosphinic acid, p-octyl-, lanthanum (3+) salt (2:1) (PMN P-10-99; CAS...

  19. 40 CFR 721.10370 - Phosphonic acid, p-octyl-, lanthanum (3+) salt (2:1).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...Phosphonic acid, p-octyl-, lanthanum (3+) salt (2:1). 721.10370 Section 721...Phosphonic acid, p-octyl-, lanthanum (3+) salt (2:1). (a) Chemical substance...phosphinic acid, p-octyl-, lanthanum (3+) salt (2:1) (PMN P-10-99; CAS...

  20. JOURNAL DE PHYSIQUE IV C2-817 Colloque C2, suppl. au Journal de Physique 11, Vol. 1, septembre 1991

    E-print Network

    Paris-Sud XI, Université de

    glass substrates as well as onto a monocrystalline silicon substrate as a function of the PH3/SiH4 flowIicon films on crystalline silicon substrates [I-31. Depositiononto glass substrate at low temperature oxidized silicon wafer) as shown in figure 1. phosphine/silane mole ratio Fig 1- Deposition rate onto glass

  1. Commercial Developments in Red Phosphorus Performance and Stability for Pyrotechnics

    Microsoft Academic Search

    Sebastian Hoerold; Andrew Ratcliff

    2001-01-01

    Red phosphorus has become an essential in- gredient in the production of modern smoke and obscurant devices. Nearly all multi-spectral developmental projects are being based on the new versions of red phosphorus available from Clariant. In pyrotechnics and munitions, phosphine liberated by the traditional red phosphorus- based smoke compounds may diffuse through the device and can give rise to corrosion

  2. Improvements in Stability of Red Phosphorus

    Microsoft Academic Search

    Sebastian Hörold

    Red phosphorus has become an essential item in the production of modern smoke and obscurants devices, additionally nearly all multi-spectral developmental projects are being based on the new versions of red phosphorus available from Clariant. In pyrotechnics and munitions, phosphine liberated by the red phosphorus charge may diffuse through the device and can give rise to corrosion of essential working

  3. COMPARATIVE RESPONSES OF THREE PSOCID SPECIES (PSOCOPTERA: LIPOSCELIDIDAE) TO FIVE FUMIGANTS

    Microsoft Academic Search

    J. RIUDAVETS; K. A. DAMCEVSKI; P. C. ANNIS

    The responses of three different psocid species, Liposcelis bostrychophila, L.!decolor and L.!paeta, were compared when treated with the fumigants carbonyl sulfide, carbon disulfide, ethyl formate, carbon dioxide and phosphine. Eggs of psocids were exposed to one applied concentration of these gases in desiccators and mortality recorded at three different exposure periods and at three different temperatures. The three psocid species

  4. Unfolding and Refolding of Aspergillus Niger PhyB Phytase: Role of Disulfide Bridges

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Role of disulfide bridges in folding of Aspergillus niger phytase pH 2.5-optimum (PhyB) was investigated using dynamic light scattering (DLS). Guanidinium chloride (GuCl) at 1.0 M unfolded phytase; however, its removal by dialysis refolded the protein. Thiol reagent, tris (2-carboxyethyl) phosphin...

  5. Dried Fruits and Nuts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Current control of postharvest insect pests of dried fruits and tree nuts relies heavily on fumigants such as methyl bromide or phosphine. There is mounting pressure against the general use of chemical fumigants due to atmospheric emissions, safety or health concerns, and an increased interest in or...

  6. Extraction of rare earth metals from nitrate solutions with a binary extractant based on Cyanex 272

    Microsoft Academic Search

    V. V. Belova; A. A. Voshkin; N. S. Egorova; A. I. Khol’kin

    2010-01-01

    Mechanisms for the extraction of rare earth metals with a binary extracting agent based on bis(2,4,4-trimethylpentyl)phosphinic\\u000a acid with the formation of various complexes in the organic phase were proposed. The compositions of the extracted compounds\\u000a were determined, and the distribution of these compounds was adequately described by calculated curves.

  7. Inorg. Chem. 1991, 30, 2615-2622 2615 Contribution from the Department of Chemistry,

    E-print Network

    Jones, William D.

    ,(n-Bu), or P(n-9~)~.The rates at which the phenyl hydride complexesreductively eliminatebenzene have been-Bu), and P(n-Bu),. In particular, we wanted to see if orthometalation of the phosphine phenyl group to give^.^ The X-ray structures of the phenyl bromide precursors have also been ex- amined to see if any obvious

  8. Uranium extraction process

    SciTech Connect

    Rose, M.A.

    1983-05-03

    Uranium is extracted from wet process phosphoric acid by extraction with a mixture of a diorganophosphate and a neutral phosphorus compound, which is preferably a triorgano phosphine oxide, in the presence of nitrate to form an organic extract layer containing uranium and an aqueous acid layer, which are separated.

  9. Natural product biosynthesis inspired concise and stereoselective synthesis of benzopyrones and related scaffolds.

    PubMed

    Baskar, Baburaj; Dakas, Pierre-Yves; Kumar, Kamal

    2011-04-15

    A natural product biosynthesis-inspired strategy to explore biologically relevant chemical space is presented. A phosphine-catalyzed cascade and stereoselective annulation provides a common tricyclic benzopyrone intermediate that was efficiently transformed into diverse and related naturally occurring scaffolds. PMID:21417315

  10. On the Phosphorus Characterization in Thin SiO2(P, B) CVD Layer Deposited onto a Silicon Substrate by PIXE

    E-print Network

    Boyer, Edmond

    On the Phosphorus Characterization in Thin SiO2(P, B) CVD Layer Deposited onto a Silicon Substrate that the phosphorus concentration in the CVD layer varies linearly with the percentage of the phosphine gas used in the CVD gas mixture. Keywords : PIXE, Low Energy PIXE, CVD, Phosphorus, SiO2, Thin layers * Correspondence

  11. Alternative fumigants to methyl bromide for killing pupae and preventing emergence of apple maggot fly (Diptera:Tephritidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Effects of methyl bromide, ECO2FUME (phosphine gas + CO2), Vapam (sodium methyldithiocarbamate), chloropicrin, Telone II (1, 3 dichloropropene), and chloropicrin + Telone II on killing the pupae and preventing adult emergence of apple maggot fly, Rhagoletis pomonella (Walsh) was determined. In an e...

  12. Catalytic Carbon-Carbon and Carbon-Silicon Bond Activation and Functionalization by Nickel Complexes

    E-print Network

    Jones, William D.

    Catalytic Carbon-Carbon and Carbon-Silicon Bond Activation and Functionalization by Nickel of Rochester, Rochester, New York 14627 Received June 11, 1999 The nickel alkyne complexes (dippe)Ni(Me3Si, and nickel phosphine complexes.3 Milstein and co-workers reported the cata- lytic hydrogenolysis

  13. A Broadly Applicable Strategy for Entry into Homogeneous Nickel(0) Catalysts from Air-Stable Nickel(II) Complexes

    E-print Network

    Müller, Peter

    A Broadly Applicable Strategy for Entry into Homogeneous Nickel(0) Catalysts from Air-Stable Nickel ABSTRACT: A series of air-stable nickel complexes of the form L2Ni(aryl) X (L = monodentate phosphine, X of precatalysts suitable for a wide variety of nickel-catalyzed transformations. These complexes are easily

  14. Catalytic Carbon-Carbon Bond Activation and Functionalization by Nickel Complexes

    E-print Network

    Jones, William D.

    Catalytic Carbon-Carbon Bond Activation and Functionalization by Nickel Complexes Brian L. Edelbach, New York 14627 Received May 24, 1999 The nickel alkyne complexes (dippe)Ni(PhCtCPh), 1, (dippe reported using (C5Me5)Rh- (PMe3)H2 5e and several platinum, palladium, and nickel phosphine complexes.5i

  15. MOVPE growth of GaAs and InP based compounds in production reactors using TBAs and TBP

    Microsoft Academic Search

    R. Beccard; D. Schmitz; J. Knauf; G. Lengeling; F. Schulte; H. Jurgensen

    1996-01-01

    For many MOVPE users the decision to switch production completely to TBP and TBAs may still be difficult as long as it is not proven that all III-V materials can be grown with TBAs\\/TBP in the same class of reactors. The aim of this study is to demonstrate that these precursors can replace arsine and phosphine for the growth of

  16. Tetraphosphine Linker Scaffolds with a Tetraphenyltin Core for Superior Immobilized Catalysts: A Solid-State NMR Study

    E-print Network

    Perera, Melanie Ingrid

    2012-10-19

    of solvent, has been studied via 31P and 2H CP/MAS and HRMAS. Our findings show that the integrity of the tetraphosphine scaffold linkers is based upon how it is immobilized. The best system is formed when the phosphine is immobilized on the SiO2 support...

  17. 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. PMID:24590817

  18. Phosphorbestimmung in organischen Stoffen nach Aufschlüssen mit Natriumperoxid oder komprimiertem Sauerstoff

    Microsoft Academic Search

    H. Buss; H. W. Kohlschütter; M. Preiss

    1965-01-01

    Fusion of organic phosphorous substances with sodium peroxide in the Parr bomb or with compressed oxygen in a calorimeter apparatus may be followed by chelatometrio phosphate determination via the precipitation of ammonium zinc phosphate. The experiments were carried out with triphenyl phosphine, tributyl phosphate and adenosine-3-monophosphoric acid. Ferrophosphorus also was fused with compressed oxygen. It was demonstrated that in this

  19. Synthesis and formulation of novel phosphorylated flame retardant curatives for thermoset resins

    Microsoft Academic Search

    M. R. Buckingham; A. J. Lindsay; D. E. Stevenson; G. Muller; E. Morel; B. Costes; Y. Henry

    1996-01-01

    More than 20 novel phosphorylated monomers have been prepared. General synthetic targets were of the form: • Di\\/tri amino cyclotriphosphazenes, • Di\\/tri hydroxy cyclotriphosphazenes, • Phosphine oxide derivatives. These dual-function materials act both as flame retardants and as curatives. Ease and cost of synthesis were taken into account in choosing promising candidates for further study. Limited formulation was then performed

  20. Spot diagnosis of aluminium phosphide ingestion: an application of a simple test.

    PubMed

    Chugh, S N; Ram, S; Chugh, K; Malhotra, K C

    1989-03-01

    Silver nitrate impregnated paper test was performed with the gastric fluid and in breath in 50 patients of aluminium phosphide poisoning. The test was 100% positive with gastric fluid but was positive in 50% patients in breath. The test is simple, reliable and sensitive method to detect phosphine (PH3) for bed side diagnosis of aluminium phosphide (AIP) ingestion. PMID:2768165

  1. JOURNAL DE PHYSIQUE Colloque C5, supplement ecu n12, Tome 43, d&aembve 1982 page C5-357

    E-print Network

    Paris-Sud XI, Université de

    forme des molecules SiH», SiO et SiPp, en phase gazeuse et du carbure SiC en phase condensee. Lorsque le of the furnace materials, silica tube and graphite boat, are analysed during the two mains operations : baking as for phosphine concentrations in the H~ carrier gas than for the Si impu- rity concentrations without baking

  2. Novel modifiers for layered double hydroxides and their effects on the properties of polylactic acid composites

    Microsoft Academic Search

    Jin Uk Ha; Marino Xanthos

    2010-01-01

    Hydrophobic modification of a carbonated layered double hydroxide (LDH) and its calcined equivalent was conducted by direct ion exchange reactions with three ionic liquids having the same phosphonium-based cation, but different anions. Among the ionic liquids, successful anionic intercalation was only carried out when calcined LDH reacted with a phosphinate anion containing ionic liquid, in excess of the stoichiometric amount.

  3. Approved quarantine treatment for Hessian fly (Diptera: Cecidomyiidae) in large-size bales and Hessian fly and cereal leaf beetle (Coleoptera: Chrysomelidae) control by bale compression

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An approved quarantine treatment using bale compression (32 kg/sq cm of pressure) and phosphine fumigation (61 g/28.2 cu m) aluminum phosphide for 7 d at 20 degrees C) was determined to control Hessian fly, Mayetiola destructor (Say), in large-size, polypropylene fabric-wrapped bales exported from t...

  4. Rhenium and Technetium Bi- and Tricarbonyl Complexes in a New Strategy for Biomolecule Incorporation using Click Chemistry

    PubMed Central

    Hayes, Thomas R.; Kasten, Benjamin B.; Barnes, Charles L.

    2014-01-01

    A versatile strategy to prepare fac-[MI(CO)3]+ and cis-[MI(CO)2]+ (M = Re, 99mTc) complexes was developed using Huisgen click chemistry and monodentate phosphine ligands to readily incorporate biomolecules and tailor the chemical properties. PMID:24710681

  5. Issue in Honor of Prof. Pawel Kafarski ARKIVOC 2012 (iv) 264-277 ARKAT-USA, Inc.

    E-print Network

    Boyer, Edmond

    to cyclic aminophosphonic and phosphinic acids David Virieux*, Jean-Noël Volle, and Jean-Luc Pirat* AM2N-mail: david.virieux@enscm.fr, jean-luc.pirat@enscm.fr In honor of Prof. Pawel Kafarski on the occasion of his

  6. Supplemental Material for Jiang et al, Tumor Imaging via Proteolytic Activation of Cell Penetrating Peptides

    E-print Network

    Tsien, Roger Y.

    by mixing equal volumes of 100 µM cyclic peptide, 10 mM TCEP [tris(2-carboxyethyl)phosphine], and 100 mM MES. Reduction was #12;confirmed by HPLC and mass spectroscopy. The final concentrations of TCEP and MES

  7. HPLC-UV determination of total vitamin C in a wide range of fortified food products

    Microsoft Academic Search

    Patric Fontannaz; Tamara Kilinç; Olivier Heudi

    2006-01-01

    A HPLC method for the quantification of total ascorbic acid (AA) and isoacorbic acid (isoAA) in fortified food products, premixes and duomixes has been developed. The method is based on the acidic extraction of AA in the presence of reducing agent Tris [2-carboxyethyl] phosphine (TCEP), which maintained AA in its reduced form. The separation was performed on a C18 column

  8. # Supplementary Material (ESI) for Chemical Communications # This journal is (c) The Royal Society of Chemistry 2006

    E-print Network

    Kwak, Juhyoun

    Experimental procedure Tris(2-carboxyethyl)phosphine (TCEP), HAuCl4·3H2O and sodium citrate dehydrate, N into an aqueous solution containing 25 mM TCEP for over 4 h. For electrochemical reduction and oxidation, polymer

  9. 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,…

  10. Domino hydroformylation/aldol condensation/hydrogenation catalysis: highly selective synthesis of ketones from olefins.

    PubMed

    Fang, Xianjie; Jackstell, Ralf; Börner, Armin; Beller, Matthias

    2014-11-24

    A general and highly chemo- and regioselective synthesis of ketones from olefins by domino hydroformylation/aldol condensation/hydrogenation reaction has been developed. A variety of olefins are efficiently converted into various ketones in good to excellent yields and regioselectivities in the presence of a specific rhodium phosphine/base-acid catalyst system. PMID:25331557

  11. Time-Resolved Infrared Spectroscopic Study of Reactive Acyl Intermediates Relevant to Cobalt-Catalyzed Carbonylations1

    E-print Network

    Bernhard, Stefan

    is relevant to the mechanism of the catalysis of alkene hydroformylation by the phosphine- modified cobalt of the chemical industry since the discovery of homogeneous cobalt carbonyl catalysts for alkene hydroformylation in 1938 by Otto Roelen at Ruhrchemie AG.2,3 The original hydroformylation catalysts were based on simple

  12. Highly regioselective osmium-catalyzed hydroformylation.

    PubMed

    Wu, Lipeng; Liu, Qiang; Spannenberg, Anke; Jackstell, Ralf; Beller, Matthias

    2015-02-21

    The first highly regioselective and general osmium-catalyzed hydroformylation of olefins to aldehydes is reported. The combination of Os3(CO)12 and imidazoyl-substituted phosphine ligands allows n-selective (up to 99%) hydroformylation of bulk aliphatic as well as functional alkenes in good yields (64-87%). PMID:25620413

  13. Metal-Catalyzed Carbon-Carbon Bond Forming Reactions for the Synthesis of Significant Chiral Building Blocks

    E-print Network

    Bugarin Cervantes, Alejandro

    2011-08-08

    ’s planar chiral DMAP derivative (II) with ee´s up to 98%. Abnormal MBH adducts are obtained employing either ethyl 2,3-butadienoate or ethyl propiolate in good yields, in the presence if MgI2 and either a tertiary amine or phosphine as the nucleophile...

  14. Stabilization of the previously unknown tautomer HP(OH)2 of hypophosphorous acid as ligand; preparation of [W3(Ni(HP(OH)2))Q4(H2O)9]4+ (Q = S, Se) complexes.

    PubMed

    Sokolov, Maxim N; Hernández-Molina, Rita; Clegg, William; Fedin, Vladimir P; Mederos, Alfredo

    2003-01-01

    Bis(hydroxy)phosphine, the isomer of hypophosphorous acid which remained elusive for a long time, coordinates to the Ni site of heterometallic clusters with a W3NiQ4 core (Q = S, Se) to give [W3(Ni(HP(OH)2))Q4(H2O)9]4+ (Q = S, Se). PMID:12611005

  15. An efficient transformation of primary halides into nitriles through palladium-catalyzed hydrogen transfer reaction.

    PubMed

    Zou, Tao; Yu, Xiaoqiang; Feng, Xiujuan; Bao, Ming

    2015-07-01

    Two-step one-pot transformation of primary halides into corresponding nitriles is successfully achieved. Nucleophilic substitution of primary halides with sodium azide and subsequent palladium-catalyzed hydrogen transfer proceeds smoothly in the presence of sterically bulky ligand dicyclohexyl(2',4',6'-triisopropylbiphenyl-2-yl)phosphine (XPhos) in acetone to produce nitriles in satisfactory to good yields. PMID:26050994

  16. Successful treatment of acute aluminium phosphide poisoning: possible benefit of coconut oil

    Microsoft Academic Search

    Shahin Shadnia; Mojgan Rahimi; Abdolkarim Pajoumand; Mohammad-Hosein Rasouli; Mohammad Abdollahi

    2005-01-01

    Aluminium phosphide is used to control rodents and pests in grain storage facilities. It produces phosphine gas, which is a mitochondrial poison. Unfortunately, there is no known antidote for aluminium phosphide intoxication, but our recent experience with a case showed that rapid prevention of absorption by coconut oil might be helpful. In the present case, we used the same protocol

  17. Rational Ligand Design for the Arylation of Hindered Primary Amines Guided by Reaction Progress Kinetic Analysis

    PubMed Central

    Ruiz-Castillo, Paula; Blackmond, Donna G.; Buchwald, Stephen L.

    2015-01-01

    We report the Pd-catalyzed arylation of very hindered ?,?,?-trisubstituted primary amines. Kinetics-based mechanistic analysis and rational design have led to the development of two biaryl phosphine ligands that allow the transformation to proceed with excellent efficiency. The process was effective in coupling a wide range of functionalized aryl and heteroaryl halides under mild conditions. PMID:25651374

  18. 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.

  19. A Mild C-O Bond Formation Catalyzed by a Rhenium-Oxo Complex Benjamin D. Sherry, Alexander T. Radosevich, and F. Dean Toste*

    E-print Network

    Toste, Dean

    A Mild C-O Bond Formation Catalyzed by a Rhenium-Oxo Complex Benjamin D. Sherry, Alexander T to terminal propargyl alcohols.5b Herein, we describe the development and application of a rhenium hindered. A rhenium(V)-oxo complex bearing a bidentate phosphine ligand (dppm ) diphenylphosphinomethane

  20. 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

  1. Copper(I) 1,1-dithiolate cluster transformations. Synthesis of [Bu 4N] 6[Cu 6(S, i-MNT) 6], i-MNT=[S 2CC(CN) 2] ?, from [Bu 4N] 4[Cu 8( i-MNT) 6] with sulfur. Reaction of the cyclic hexanuclear complex with phosphine to give the tetrahedral [Bu 4N] 4[Cu 4( i-MNT) 4] which oxidizes in solution to give the homocubane [Bu 4N] 4[Cu 8( i-MNT) 6] and [Bu 4N] 2[Cu( i-MNT) 2

    Microsoft Academic Search

    C. W. Liu; Richard J. Staples; John P. Fackler

    1998-01-01

    The novel sulfur-rich cluster anion, [Cu6(S,i-MNT)6]6?, 2, is obtained from the reaction of the homocubane, [Cu8(i-MNT)6]4?, 1, and powdered sulfur in acetonitrile solution under basic conditions. Compound 2 crystallizes in the R bar 3 space group with a=33.519(5)Å, b=33.519(5)Å, c=11.748(2)Å, ?=120°, and V=11431(3)Å3. The molecule contains six trigonally coordinated copper atoms linked together into a 12 membered ring by the

  2. Reactivity of Metal Ions Bound to Water-Soluble Polymers

    SciTech Connect

    Sauer, N.N.; Watkins, J.G.; Lin, M.; Birnbaum, E.R.; Robison, T.W.; Smith, B.F.; Gohdes, J.W.; McDonald, J.G.

    1999-06-29

    The intent of this work is to determine the effectiveness of catalysts covalently bound to polymers and to understand the consequences of supporting the catalysts on catalyst efficiency and selectivity. Rhodium phosphine complexes with functional groups for coupling to polymers were prepared. These catalyst precursors were characterized using standard techniques including IR, NMR, and elemental analysis. Studies on the modified catalysts showed that they were still active hydrogenation catalysts. However, tethering of the catalysts to polyamines gave systems with low hydrogenation activity. Analogous biphasic systems were also explored. Phosphine ligands with a surfactant-like structure have been synthesized and used to prepare catalytically active complexes of palladium. The palladium complexes were utilized in Heck-type coupling reactions (e.g. coupling of iodobenzene and ethyl acrylate to produce ethyl cinnamate) under vigorously stirred biphasic reaction conditions, and were found to offer superior performance over a standard water-soluble palladium catalyst under analogous conditions.

  3. Hydrogen generation at ambient conditions: application in fuel cells.

    PubMed

    Boddien, Albert; Loges, Björn; Junge, Henrik; Beller, Matthias

    2008-01-01

    The efficient generation of hydrogen from formic acid/amine adducts at ambient temperature is demonstrated. The highest catalytic activity (TOF up to 3630 h(-1) after 20 min) was observed in the presence of in situ generated ruthenium phosphine catalysts. Compared to the previously known methods to generate hydrogen from liquid feedstocks, the systems presented here can be operated at room temperature without the need for any high-temperature reforming processes, and the hydrogen produced can then be directly used in fuel cells. A variety of Ru precursors and phosphine ligands were investigated for the decomposition of formic acid/amine adducts. These catalytic systems are particularly interesting for the generation of H2 for new applications in portable electric devices. PMID:18686291

  4. New entries in Lewis acid-Lewis base bifunctional asymmetric catalyst: catalytic enantioselective Reissert reaction of pyridine derivatives.

    PubMed

    Ichikawa, Eiko; Suzuki, Masato; Yabu, Kazuo; Albert, Matthias; Kanai, Motomu; Shibasaki, Masakatsu

    2004-09-29

    The first catalytic enantioselective Reissert reaction of pyridine derivatives that affords products with excellent regio- and enantioselectivity is described. The key for success is the development of new Lewis acid-Lewis base bifunctional asymmetric catalysts containing an aluminum as a Lewis acid and sulfoxides or phosphine sulfides as a Lewis base. These reactions are useful for the synthesis of a variety of chiral piperidine subunits, and catalytic enantioselective formal synthesis of CP-293,019, a selective D4 receptor antagonist, was achieved. Preliminary mechanistic studies indicated that both sulfoxides and phosphine sulfides can activate TMSCN as a Lewis base. In addition, the sulfoxides with appropriate stereochemistry might stabilize a highly enantioselective bimetallic complex (a presumed active catalyst) through internal coordination to aluminum. PMID:15382912

  5. Room temperature asymmetric Pd-catalyzed methoxycarbonylation of norbornene: highly selective catalysis and HP-NMR studies.

    PubMed

    Blanco, Carolina; Godard, Cyril; Zangrando, Ennio; Ruiz, Aurora; Claver, Carmen

    2012-06-21

    Palladium complexes bearing monodentate and bidentate phosphine ligands (1-7) were synthesised and used as catalyst precursors in the methoxycarbonylation of norbornene. The catalytic systems bearing ligands 1, 3 and 4 afforded excellent conversions (>99%) and selectivity of the ester (>99%). NMR investigations showed that using complex 1a as the precursor resulted in the protonated phosphine, 1-H(+), being formed under catalytic conditions and thus the addition of acid is not required for the activation of this system since the reaction involving the precursor with methanol under CO pressure produces 2 equivalents of HCl and leads to the formation of the active species. The protonation of ligand 4 under methoxycarbonylation conditions was also observed and the diprotonated diphosphine was isolated and characterised. This compound was tested as a ligand and acid source in a catalysis and provided excellent conversion and high selectivity to the ester. PMID:22535338

  6. Synthesis and application of pyridine-based ambipolar hosts: control of charge balance in organic light emitting devices (OLEDs) by chemical structure modification

    SciTech Connect

    Koech, Phillip K.; Polikarpov, Evgueni; Rainbolt, James E.; Cosimbescu, Lelia; Swensen, James S.; Von Ruden, Amber L.; Padmaperuma, Asanga B.

    2010-11-05

    Pyridine-based host materials were synthesized via Grignard metathesis of bromopyridines to provide the required organometallic reagent. The isomeric hosts (4-(9H-carbazol-9-yl)phenyl)(phenyl)(pyridin-3-yl)phosphine oxide (HM-A4), (5-(9H-carbazol-9-yl)pyridin-2-yl)diphenylphosphine oxide (HM-A5), and (5-(diphenylamino)pyridin-2-yl)diphenylphosphine oxide (HM-A6), (4-(diphenylamino)phenyl)(phenyl)(pyridin-3-yl)phosphine oxide (HM-A8) have similar frontier orbital energies. Organic light emitting devices (OLEDs) fabricated using the series of the host materials demonstrate that small structural modification of the host results in significant change in charge transporting ability.

  7. 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. [Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83415 (United States)

    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)

  8. 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.

  9. Alternatives to methyl bromide treatments for stored-product and quarantine insects.

    PubMed

    Fields, Paul G; White, Noel D G

    2002-01-01

    Methyl bromide is used to control insects as a space fumigant in flour and feed mills and ship holds, as a product fumigant for some fruit and cereals, and for general quarantine purposes. Methyl bromide acts rapidly, controlling insects in less than 48 h in space fumigations, and it has a wide spectrum of activity, controlling not only insects but also nematodes and plant-pathogenic microbes. This chemical will be banned in 2005 in developed countries, except for exceptional quarantine purposes, because it depletes ozone in the atmosphere. Many alternatives have been tested as replacements for methyl bromide, from physical control methods such as heat, cold, and sanitation to fumigant replacements such as phosphine, sulfuryl fluoride, and carbonyl sulfide, among others. Individual situations will require their own type of pest control techniques, but the most promising include integrated pest management tactics and combinations of treatments such as phosphine, carbon dioxide, and heat. PMID:11729078

  10. 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. PMID:21887733

  11. MOVPE growth of high performance photodetector structures using TBA and TBP

    SciTech Connect

    Weber, J.; Nowitzki, A.; Gyuro, I.; Scherb, J. [Alcatel Telecom, Stuttgart (Germany). Research Div.

    1996-12-31

    Tertiary-butyl-arsine (TBA) and tertiary-butyl-phosphine (TBP) are common alternative group V precursors for the replacement of the highly toxic arsine and phosphine. The authors demonstrate, that high performance devices like pin-photodetectors grown with TBA and TBP show excellent device characteristics. Extremely low dark currents of I{sub D} < 100 pA at {minus}5 V are found for 55 {micro}m planar pin-photodiodes with an yield of 99%. Also planar 300 {micro}m diodes and mesa pin photodetectors (40 {micro}m) were processed and investigated. In both cases very low dark currents of I{sub D} < 0.6 nA at {minus}5 V were measured. Beside safety aspects, the improvements in device properties together with high yields (>95%) demonstrate the suitability of TBA and TBP for the growth of high performance pin-photodetectors.

  12. On the compensation mechanism of amorphous silicon films: Study of stability

    SciTech Connect

    Caputo, D.; De Cesare, G.; Palma, F.; Tucci, M.; Minarini, C.; Terzini, E.

    1997-07-01

    The authors investigated a-Si:H compensated materials deposited over a wide range of gas dopant concentrations, from 0.125 ppm up to 10{sup 3} ppm. They achieved compensation for different ratio in the gas phase of diborane and phosphine, depending on their concentration. As a relevant result, they found that at constant boron concentration compensation occurs by using two different values of phosphine flow. This behavior can be described by a change of formation mechanism involving active dopants, defects and boron-phosphorus complex, that occurs in a different way depending on the dopant concentrations. The two compensation regimes are evidenced also by a different behavior under light soaking. Furthermore they found that photocurrent evolution under illumination is determined by two concurrent mechanisms: activation of dopant species and increase of defect density.

  13. Influence of coligands on the. eta. sup 1 -coordination mode of SO sub 2 in L sub 3 NiSO sub 2 complexes. A pseudopotential ab initio study

    SciTech Connect

    Reinhold, J.; Schueler, M. (Univ. of Leipzig (Germany)); Hoffmann, T.; Wenschuh, E. (Humboldt Univ., Berlin (Germany))

    1992-02-19

    In tris(phosphine)(sulfur dioxide)nickel(0) complexes the mode of {eta}{sup 1}-coordination of SO{sub 2} depends in a very sensitive way on the nature of the phosphine coligands, i.e., their electronic and steric influences. MO calculations on the pseudopotential ab initio level show that the experimental structure ({eta}{sup 1}-pyramidal vs {eta}{sup 1}-coplanar coordination of SO{sub 2}) is a consequence of various different and partially counteracting influences of the coligands. The recently found unusual {eta}{sup 1}-pyramidal mode as compared to the usual {eta}{sup 1}-coplanar one can be expected to be obtained by coligands which are small and have strong donor power as well.

  14. 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.

  15. Toroid NMR probes for the in situ examination of homogeneous cobalt hydroformylation catalysts at high pressures and temperatures.

    SciTech Connect

    Kramarz, K. W.; Klingler, R. J.; Fremgen, D. E.; Rathke, J. W.; Chemical Engineering

    1999-03-01

    Toroid NMR probes can be routinely operated at 300 atm and up to 250 C. Such operating conditions make these probes well suited for the in situ examination of catalytic industrial processes. These probes have been employed to examine phosphine substituted (Shell-type) and unsubstituted cobalt carbonyl oxo catalysts under catalytic and non-catalytic conditions in a variety of solvents. The solvents include cyclohexane, benzene, dioxane, 2-methylpropanol, supercritical carbon dioxide (scCO{sub 2}), and scCO{sub 2}/toluene mixtures. The high-pressure/high-temperature probes allowed the observation of precatalytic equilibria under high carbon monoxide pressures in the presence and absence of hydrogen and/or free phosphine.

  16. Coordination Chemistry of Cyclic Disilylated Stannylenes and Plumbylenes to Group 4 Metallocenes

    PubMed Central

    2012-01-01

    Reduction of group 4 metallocene dichlorides with magnesium in the presence of cyclic disilylated stannylene or plumbylene phosphine adducts yielded the respective metallocene tetrylene phosphine complexes. Under the same conditions the use of the respective dimerized stannylene or plumbylene gave metallocene ditetrylene complexes. A computational analysis of these reactions revealed for all investigated compounds multiple-bonded character for the M–E(II) linkage, which can be rationalized in the case of the monotetrylene complex with the classical ?-donor/?-acceptor interaction. The strength of the M–E(II) bond increases descending group 4 and decreases going from Sn to its heavier congener Pb. The weakness of the Ti–E(II) bonds is caused by the significantly reduced ability of the titanium atom for d–p ?-back-bonding. PMID:22716501

  17. Iron in a trigonal tris(alkoxide) ligand environment.

    PubMed

    Chambers, Matthew B; Groysman, Stanislav; Villagrán, Dino; Nocera, Daniel G

    2013-03-18

    Mononuclear Fe(II) and Fe(III) complexes residing in a trigonal tris(ditox) (ditox = (t)Bu2(Me)CO(-)) ligand environment have been synthesized and characterized. The Fe(III) ditox complex does not react with oxidants such as PhIO, whereas NMe3O substitutes a coordinated tetrahydrofuran (THF) in the apical position without undergoing oxo transfer. In contrast, the Fe(II) ditox complex reacts rapidly with PhIO or Me3NO in THF or cyclohexadiene to furnish a highly reactive intermediate, which cleaves C-H bonds to afford the Fe(III)-hydroxide complex. When generated in 1,2-difluorobenze, this intermediate can be intercepted to oxidize phosphines to phosphine oxide. The fast rates at which these reactions occur is attributed to a particularly weak ligand field imparted by the tris(alkoxide) ancillary ligand environment. PMID:23432161

  18. Dithioacetals as C{sup 2+} cation synthons

    SciTech Connect

    Tien-Yau Luh [National Taiwan Univ., Taipei (China)

    1995-12-31

    The nickel-catalyzed cross coupling reactions of the benzylic and allylic dithioacetal group with Grignard reagents group giving olefins will be presented. The reaction provides a convenient procedure for the synthesis of various vinylsilanes and silyl-substituted conjugated dienes. Allylic dithioacetals undergo geminal dimethylation reactions when bidentate phosphine ligands are used. Treatment of dithioacetals with geminal dimetallic species affords the corresponding olefination products.

  19. Cationic complexes of Eu(III) and Sr(II) with diphosphine dioxides in organic extracts

    Microsoft Academic Search

    E. S. Stoyanov; T. P. Vorob’yova; I. V. Smirnov

    2005-01-01

    IR spectroscopy was used to study the structure and composition of Eu(III) and Sr(II) complexes formed by cation-exchange\\u000a extraction of these metals from their aqueous nitrate solutions with dichlorethane solutions of mixtures of chlorinated cobalt(III)\\u000a dicarbollide (CCD) as a superacid with diphenyldiphosphine dioxides containing a methyl (Me-DPDO), ethyl (Et-DPDO), or polyoxyethylene\\u000a bridge between two phosphorus atoms of phosphine oxide groups.

  20. Diversity through a branched reaction pathway: generation of multicyclic scaffolds and identification of antimigratory agents

    Microsoft Academic Search

    Z. Wang; S. Castellano; S. S. Kinderman; C. E. Argueta; A. B. Beshir; G. Fenteany; O. Kwon

    2011-01-01

    A library of 91 heterocyclic compounds composed of 16 distinct scaffolds has been synthesized through a sequence of phosphine-catalyzed ring-forming reactions, Tebbe reactions, Diels–Alder reactions, and, in some cases, hydrolysis. This effort in diversity-oriented synthesis produced a collection of compounds that exhibited high levels of structural variation both in terms of stereochemistry and the range of scaffolds represented. A simple

  1. Simultaneous removal and recovery of cadmium (II) and CN ? from simulated electroplating rinse wastewater by a strip dispersion hybrid liquid membrane (SDHLM) containing double carrier

    Microsoft Academic Search

    Dingsheng He; Shuxiang Gu; Ming Ma

    2007-01-01

    A novel liquid membrane system, denoted strip dispersion hybrid liquid membrane (SDHLM) with a double carrier (TRPO, trialkyl-phosphine oxide, and D2EHPA, di-(2-ethylhexyl) phosphoric acid) membrane phase, basic stripping aqueous phase and weak acidic waste water phase, was reported for the simultaneous removal and recovery of Cd(II) and CN? from simulated electroplating rinse wastewater. The basic stripping solution containing the concentrated

  2. Synthesis of hcp-Co nanodisks

    SciTech Connect

    Puntes, Victor F.; Zanchet, Daniela; Erdonmez, Can K.; Alivisatos, A.P.

    2002-06-11

    hcp Co disk-shaped nanocrystals were obtained by rapid decomposition of cobalt carbonyl in presence of linear amines. Other surfactants, in addition to the amines, like phosphine oxides and oleic acid were used to improve size dispersion, shape control and nanocrystal stability. Co disks are ferromagnetic in character and they spontaneously self-assemble into long ribbons. X-ray and electron diffraction, electron microscopy and SQUID magnetometry have been employed to characterize this material.

  3. Molecularly engineering homogenous catalysts

    E-print Network

    Hughes, Reagan Rebekah

    2013-02-22

    (II) catalysts that proved to be active. Denmark's use of oxazoline ligands avoided the problem of phosphine oxidation. They were also inspired by Milstein and coworkers description of a phosphorus-carbon-phosphorus (PCP)-type tridentate ligand.... The magnesium 38 sulfate was removed by filtration and the organic phase was concentrated under reduced pressure using a rotary evaporator to a volume of ca. 8 mL. This more concentrated methylene chloride solution of the crude active ester product...

  4. Upper limits for PH3 and H2S in Titan's Atmosphere from Cassini CIRS

    E-print Network

    Nixon, Conor A; Irwin, Patrick G J; Horst, Sarah M; 10.1016/j.icarus.2013.02.024

    2013-01-01

    We have searched for the presence of simple P and S-bearing molecules in Titan's atmosphere, by looking for the characteristic signatures of phosphine and hydrogen sulfide in infrared spectra obtained by Cassini CIRS. As a result we have placed the first upper limits on the stratospheric abundances, which are 1 ppb (PH3) and 330 ppb (H2S), at the 2-sigma significance level.

  5. Vibrational analysis of pyramidal XY3-type molecules based on high-level ab initio potential energy surfaces: application to NH3

    Microsoft Academic Search

    H. Lin; W. Thiel; S. N. Yurchenko; M. Carvajal; P. Jensen

    2003-01-01

    Variational calculations of the vibrational energies of the non-rigid and semirigid XY3 molecules, as ammonia and phosphine respectively, have been carried out [1,2]. In the procedure used is emphasized the umbrella motion due to the corresponding coordinate, for pyramidal non-rigid XY3 molecules, is the responsible of the torsional tunneling between different minima of the Potential Energy Surfaces. For the NH3

  6. Reactions of nitroxides 15. Cinnamates bearing a nitroxyl moiety synthesized using a Mizoroki–Heck cross-coupling reaction

    PubMed Central

    Huras, Bogumi?a

    2015-01-01

    Summary Cinnamic acid derivatives bearing a nitroxyl moiety (2,2,6,6-tetramethyl-1-oxyl-4-piperidyl 3-E-aryl acrylates) were synthesized in 30–100% yield using a Mizoroki–Heck cross-coupling reaction between 4-acryloyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl and iodobenzene derivatives in the presence of palladium(II) acetate coordinated with a tri(o-tolyl)phosphine ligand immobilized in a polyurea matrix. PMID:26199672

  7. Determination of hydroperoxides and structures by high-performance liquid chromatography with post-column detection with diphenyl-1-pyrenylphosphine

    Microsoft Academic Search

    Toshiaki Ohshima; Anu Hopia; J. Bruce German; Edwin N. Frankel

    1996-01-01

    A high-performance liquid chromatographic method, using post-column detection with diphenyl-1-pyrenyl-phosphine (DPPP), was\\u000a developed for the quantitative and qualitative determination of isomeric lipid hydroperoxides (OOH). The OOH eluted from a\\u000a normal-phase column were passed through a photodiode array detector and then mixed with DPPP solution in a reaction coil heated\\u000a at 80°C. DPPP oxide formed by the reaction with OOH was

  8. Synthesis and Characterization of Gold Clusters Ligated with 1,3-Bis(dicyclohexylphosphino)propane

    SciTech Connect

    Johnson, Grant E.; Priest, Thomas A.; Laskin, Julia

    2013-09-01

    In this multidisciplinary study we combine chemical reduction synthesis of novel gold clusters in solution with high-resolution analytical mass spectrometry (MS) to gain insight into the composition of the gold clusters and how their size, ionic charge state and ligand substitution influences their gas-phase fragmentation pathways. Ultra small cationic gold clusters ligated with 1,3-bis(dicyclohexylphosphino)propane (DCPP) were synthesized for the first time and introduced into the gas phase using electrospray ionization (ESI). Mass-selected cluster ions were fragmented employing collision induced dissociation (CID) and the product ions were analysed using MS. The solutions were found to contain the multiply charged cationic gold clusters Au9L43+, Au13L53+, Au6L32+, Au8L32+ and Au10L42+ (L = DCPP). The gas-phase fragmentation pathways of these cluster ions were examined systematically employing CID combined with MS. In addition, CID experiments were performed on related gold clusters of the same size and ionic charge state but capped with 1,3-bis(diphenylphosphino)propane (DPPP) ligands containing phenyl functional groups at the two phosphine centers instead of cyclohexane rings. It is shown that this relatively small change in the molecular substitution of the two phosphine centers in diphosphine ligands (C6H11 versus C6H5) exerts a pronounced influence on the size of the species that are preferentially formed in solution during reduction synthesis as well as the gas-phase fragmentation channels of otherwise identical gold cluster ions. The mass spectrometry results indicate that in addition to the length of the alkyl chain between the two phosphine centers, the substituents at the phosphine centers also play a crucial role in determining the composition, size and stability of diphosphine ligated gold clusters synthesized in solution.

  9. Dynamic tests for actinide/lanthanide separation by CMPO solvent in fluorinated diluents

    SciTech Connect

    Tkachenko, L.; Babain, V.; Alyapyshev, M.; Vizniy, A.; Il'in, A. [V. G. Khlopin Radium Institute, 2nd Murinskiy Ave 28., St. Petersburg 194021 (Russian Federation); Shadrin, A. [A.A. Bochvar High-technology Research Institute of Inorganic Materials, 5-a, Rogova str., Moscow 123098 (Russian Federation)

    2013-07-01

    Actinide and lanthanide extraction by new solvent: 0.2 M phenyl-octyl-N,N-diiso-butylcarbamoyl-phosphine oxide (CMPO) + 30% TBP + formal of octafluoro-pentanol was studied. A dynamic test with this solvent was performed. It was shown that americium and lanthanides are effectively extracted from PUREX process raffinate. The separation of americium from light lanthanides was confirmed in the modified SETFICS flowsheet with this new solvent. (authors)

  10. Triple-Helical Transition State Analogs: A New Class of Selective Matrix Metalloproteinase Inhibitors

    PubMed Central

    Lauer-Fields, Janelle; Brew, Keith; Whitehead, John K.; Li, Shunzi; Hammer, Robert P.; Fields, Gregg B.

    2008-01-01

    Alterations in activities of one family of proteases, the matrix metalloproteinases (MMPs), have been implicated in primary and metastatic tumor growth, angiogenesis, and pathological degradation of extracellular matrix (ECM) components, such as collagen and laminin. Since hydrolysis of the collagen triple-helix is one of the committed steps in ECM turnover, we envisioned modulation of collagenolytic activity as a strategy for creating selective MMP inhibitors. In the present study, a phosphinate transition state analog has been incorporated within a triple-helical peptide template. The template sequence was based on the ?1(V)436-450 collagen region, which is hydrolyzed at the Gly439~Val440 bond selectively by MMP-2 and MMP-9. The phosphinate acts as a tetrahedral transition state analog, which mimics the water-bound peptide bond of a protein substrate during hydrolysis. The phosphinate replaced the amide bond between Gly-Val in the P1-P1? subsites of the triple-helical peptide. Inhibition studies revealed Ki values in the low nanomolar range for MMP-2 and MMP-9 and low to middle micromolar range for MMP-8 and MMP-13. MMP-1, MMP-3, and MT1-MMP/MMP-14 were not inhibited effectively. Melting of the triple-helix resulted in a decrease in inhibitor affinity for MMP-2. The phosphinate triple-helical transition state analog has high affinity and selectivity for the gelatinases (MMP-2 and MMP-9), and represents a new class of protease inhibitors that maximizes potential selectivity via interactions with both prime and non-prime active site subsites as well as with secondary binding sites (exosites). PMID:17672455

  11. Rhenium and technetium tricarbonyl complexes anchored by 5HT 1A receptor-binding ligands containing P,O\\/N donor atom sets

    Microsoft Academic Search

    Elisa Palma; João D. G. Correia; Ângela Domingos; Isabel Santos; Roger Alberto; Hartmut Spies

    2004-01-01

    The (2-methoxyphenyl)piperazine pharmacophore, a part of the WAY 100635 structure, has been functionalized with phosphinoarylbenzylamide or phosphinoarylbenzylamine chelator groups using propylene or hexylene alkyl chains as linkers (L2–L4). These heterofunctionalized phosphines bearing an arylpiperazine moiety have been used to stabilize rhenium tricarbonyl complexes of the type [Re(CO)3Br(?2-L)] (4, L=L2; 5, L=L3; 6, L=L4), which have been fully characterized, including by

  12. Extraction of Trivalent Lanthanides and Americium by Tri-n-octylphosphine Oxide from Ammonium Thiocyanate Media

    Microsoft Academic Search

    Derek Brigham; Coralie Badajoz; Gerard Cote; Kenneth L. Nash

    2011-01-01

    An investigation of the solvent extraction of trivalent lanthanides and Am from ammonium-thiocyanate media by tri(n-octyl)phosphine oxide (TOPO) in toluene has been completed. This system is of interest both for its potential as a means of separating transplutonium actinides from fission-product lanthanides and for inherent interest in thiocyanate-based solvent extraction systems. Partitioning was monitored using radiotracer techniques where appropriate, and

  13. A novel ammonium ionic liquid based extraction strategy for separating scandium from yttrium and lanthanides

    Microsoft Academic Search

    Xiaoqi Sun; Yang Ji; Lin Guo; Ji Chen; Deqian Li

    2011-01-01

    Ionic liquid (IL)-based extraction is a promising high-efficiency and environmentally benign separation technology. Imidazolium ILs lose their cations or anions to aqueous phase during extraction, the release lead to water pollution. To develop sustainable IL-based extraction system, we firstly investigate quaternary ammonium nitrate IL-based extraction strategy. Alkylated phosphine oxides (Cyanex925) in tricaprylmethylammonium nitrate ([A336][NO3]) are studied for separating Sc from

  14. 1,2-Diphosphonium Dication: A Strong P-Based Lewis Acid in Frustrated Lewis Pair (FLP)-Activations of B-H, Si-H, C-H, and H-H Bonds.

    PubMed

    Holthausen, Michael H; Bayne, Julia M; Mallov, Ian; Dobrovetsky, Roman; Stephan, Douglas W

    2015-06-17

    A highly Lewis acidic diphosphonium dication [(C10H6)(Ph2P)2](2+) (1), in combination with a Lewis basic phosphine, acts as a purely phosphorus-based frustrated Lewis pair (FLP) and abstracts hydride from [HB(C6F5)3](-) and Et3SiH demonstrating the remarkable hydridophilicity of 1. The P-based FLP is also shown to activate H2 and C-H bonds. PMID:26030269

  15. Phosphorus-containing imide resins

    NASA Technical Reports Server (NTRS)

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

    1984-01-01

    Flame-resistant reinforced bodies are disclosed which are composed of reinforcing fibers, filaments or fabrics in a cured body of bis- and tris-imide resins derived from tris(m-aminophenyl) phosphine oxides by reaction with maleic anhydride or its derivatives, or of 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.

  16. Replacement of hydrides by TBAs and TBP for the growth of various III–V materials in production scale MOVPE reactors

    Microsoft Academic Search

    R. Beccard; G. Lengeling; D. Schmitz; Y. Gigase; H. Jürgensen

    1997-01-01

    Besides the standard group V precursors AsH3 and PH3, so-called alternative precursors like TBAs and TBP (tertiary-butyl-arsine and tertiary-butyl-phosphine) are more and more important in today's MOVPE processes. A lot of publications have demonstrated that these precursors can be successfully used for the growth of different III–V materials. In this study we want to demonstrate that TBAs and TBP can

  17. Ruthenium complex-catalyzed anti-Markovnikov hydration of terminal alkynes.

    PubMed

    Suzuki, T; Tokunaga, M; Wakatsuki, Y

    2001-03-01

    [reaction: see text]. Highly regioselective, efficient, and substituent-tolerant anti-Markovnikov hydration of terminal alkynes occurs to give n-aldehyde by use of a catalytic amount of easily available cyclopentadienylruthenium complexes bearing appropriate bidentate or monodentate phosphine ligands. Typically, RuCpCl(dppm) (1 mol %) catalyzes the addition of water to 1-hexyne at 100 degrees C to give hexanal in 95% yield: 2-hexanone is not detected at all. PMID:11259049

  18. On the Functional Group Tolerance of Ester Hydrogenation and Polyester Depolymerisation Catalysed by Ruthenium Complexes of Tridentate Aminophosphine Ligands.

    PubMed

    Fuentes, José A; Smith, Samuel M; Scharbert, M Theresa; Carpenter, Ian; Cordes, David B; Slawin, Alexandra M Z; Clarke, Matthew L

    2015-07-20

    The synthesis of a range of phosphine-diamine, phosphine-amino-alcohol, and phosphine-amino-amide ligands and their ruthenium(II) complexes are reported. Five of these were characterised by X-ray crystallography. The activities of this collection of catalysts were initially compared for the hydrogenation of two model ester hydrogenations. Catalyst turnover frequencies up to 2400?h(-1) were observed at 85?°C. However, turnover is slow at near ambient temperatures. By using a phosphine-diamine Ru(II) complex, identified as the most active catalyst, a range of aromatic esters were reduced in high yield. The hydrogenation of alkene-, diene-, and alkyne-functionalised esters was also studied. Substrates with a remote, but reactive terminal alkene substituent could be reduced chemoselectively in the presence of 4-dimethylaminopyridine (DMAP) co-catalyst. The chemoselective reduction of the ester function in conjugated dienoate ethyl sorbate could deliver (2E,4E)-hexa-2,4-dien-1-ol, a precursor to leaf alcohol. The monounsaturated alcohol (E)-hex-4-en-1-ol was produced with reasonable selectivity, but complete chemoselectivity of C?O over the diene is elusive. High chemoselectivity for the reduction of an ester over an alkyne group was observed in the hydrogenation of an alkynoate for the first time. The catalysts were also active in the depolymerisation reduction of samples of waste poly(ethylene terephthalate) (PET) to produce benzene dimethanol. These depolymerisations were found to be poisoned by the ethylene glycol side product, although good yields could still be achieved. PMID:26176880

  19. Supramolecular Allosteric Cofacial Porphyrin Complexes

    PubMed Central

    Oliveri, Christopher G.; Gianneschi, Nathan C.; Nguyen, SonBinh T.; Mirkin, Chad A.; Stern, Charlotte L.; Wawrzak, Zdzislaw; Pink, Maren

    2008-01-01

    Nature routinely uses cooperative interactions to regulate cellular activity. For years, chemists have designed synthetic systems that aim toward harnessing the reactivity common to natural biological systems. By learning how to control these interactions in situ, one begins to allow for the preparation of man-made biomimetic systems that can efficiently mimic the interactions found in Nature. To this end, we have designed a synthetic protocol for the preparation of flexible metal-directed supramolecular cofacial porphyrin complexes which are readily obtained in greater than 90% yield through the use of new hemilabile porphyrin ligands with bifunctional ether–phosphine or thioether–phosphine substituents at the 5 and 15 positions on the porphyrin ring. The resulting architectures contain two hemilabile ligand–metal domains (RhI or CuI sites) and two cofacially aligned porphyrins (ZnII sites), offering orthogonal functionalities and allowing these multimetallic complexes to exist in two states, “condensed” or “open”. Combining the ether–phosphine ligand with the appropriate RhI or CuI transition-metal precursors results in “open” macrocyclic products. In contrast, reacting the thioether–phosphine ligand with RhI or CuI precursors yields condensed structures that can be converted into their “open” macrocyclic forms via introduction of additional ancillary ligands. The change in cavity size that occurs allows these structures to function as allosteric catalysts for the acyl transfer reaction between X-pyridylcarbinol (where X = 2, 3, or 4) and 1-acetylimidazole. For 3-and 4-pyridylcarbinol, the “open” macrocycle accelerates the acyl transfer reaction more than the condensed analogue and significantly more than the porphyrin monomer. In contrast, an allosteric effect was not observed for 2-pyridylcarbinol, which is expected to be a weaker binder and is unfavorably constrained inside the macrocyclic cavity. PMID:17165783

  20. Mono(amido-diphosphine) complexes of yttrium: Synthesis and X-ray crystal structure of (Y({eta}{sup 3}-C{sub 3}H{sub 5})[N(SiMe{sub 2}CH{sub 2}PMe{sub 2}){sub 2}]){sub 2}({mu}-Cl){sub 2}

    SciTech Connect

    Fryzuk, M.D.; Haddad, T.S.; Rettig, S.J. [Univ. of British Columbia, Vancouver (Canada)

    1992-09-01

    The reaction of allylmagnesium chloride with the bis(amido-phosphine) complex YCl[N-(SiMe{sub 2}CH{sub 2}PMe{sub 2}){sub 2}]{sub 2} (1) results in displacement of one of the tridentate ligands rather than simple metathesis of the chloride to generate the new complex [Y({eta}{sup 3}-C{sub 3}H{sub 5})[N-(SiMe{sub 2}CH{sub 2}PMe{sub 2}){sub 2}

  1. Rhenium(V) and technetium(V) complexes of bis(o-hydroxyphenyl)phenylphosphine (PO{sub 2}{sup 2-}) and (o-hydroxyphenyl)diphenylphosphine (PO{sup -}) ligands

    SciTech Connect

    Luo, Hongyan; Setyawati, Ika; Rettig, S.J.; Orvig, C. [Univ. of British Columbia, Vancouver (Canada)

    1995-04-26

    The synthesis of several phosphine-based chelating compounds and chelates formed between these compounds and rhenium or technetium is discussed. Four categories of products result, (i) bis-(o-hydroxyphenyl) diphenylphosphine (PO) complexes, (ii) mono- (PO) complexes, (iii) bis-bis(o-hydroxyphenyl)-phenylphosphine (PO{sub 2}) complexes, and mixed-(PO) and (PO{sub 2}) complexes. Molecular structures of these compounds (including isomers) were probed by NMR, MS, and IR spectroscopies and by X-ray crystallography.

  2. A North-South Comparison of Saturn's Infrared Spectrum

    Microsoft Academic Search

    Nancy J. Chanover; G. L. Bjoraker; T. Hewagama; D. Glenar; K. H. Baines

    2007-01-01

    We compare the strength and shape of the ammonia and phosphine absorption bands in Saturn's northern and southern hemispheres. Infrared spectra between 2.7 and 5.5 microns (R 2000) were acquired using SpeX at the NASA Infrared Telescope Facility in support of Cassini\\/CIRS and VIMS observations of Saturn's atmosphere. We present analysis of data that were acquired during 2005-2007, during which

  3. Supramolecular Allosteric Cofacial Porphyrin Complexes

    SciTech Connect

    Oliveri, Christopher G.; Gianneschi, Nathan C.; Nguyen, Son Binh T.; Mirkin, Chad A.; Stern, Charlotte L.; Wawrzak, Zdzislaw; Pink, Maren (NWU); (Indiana)

    2008-04-12

    Nature routinely uses cooperative interactions to regulate cellular activity. For years, chemists have designed synthetic systems that aim toward harnessing the reactivity common to natural biological systems. By learning how to control these interactions in situ, one begins to allow for the preparation of man-made biomimetic systems that can efficiently mimic the interactions found in Nature. To this end, we have designed a synthetic protocol for the preparation of flexible metal-directed supramolecular cofacial porphyrin complexes which are readily obtained in greater than 90% yield through the use of new hemilabile porphyrin ligands with bifunctional ether-phosphine or thioether-phosphine substituents at the 5 and 15 positions on the porphyrin ring. The resulting architectures contain two hemilabile ligand-metal domains (Rh{sup I} or Cu{sup I} sites) and two cofacially aligned porphyrins (Zn{sup II} sites), offering orthogonal functionalities and allowing these multimetallic complexes to exist in two states, 'condensed' or 'open'. Combining the ether-phosphine ligand with the appropriate Rh{sup I} or Cu{sup I} transition-metal precursors results in 'open' macrocyclic products. In contrast, reacting the thioether-phosphine ligand with RhI or CuI precursors yields condensed structures that can be converted into their 'open' macrocyclic forms via introduction of additional ancillary ligands. The change in cavity size that occurs allows these structures to function as allosteric catalysts for the acyl transfer reaction between X-pyridylcarbinol (where X = 2, 3, or 4) and 1-acetylimidazole. For 3- and 4-pyridylcarbinol, the 'open' macrocycle accelerates the acyl transfer reaction more than the condensed analogue and significantly more than the porphyrin monomer. In contrast, an allosteric effect was not observed for 2-pyridylcarbinol, which is expected to be a weaker binder and is unfavorably constrained inside the macrocyclic cavity.

  4. Synthesis of tungsten nanoparticles by solvothermal decomposition of tungsten hexacarbonyl

    Microsoft Academic Search

    Prasanta Kumar Sahoo; S. S. Kalyan Kamal; M. Premkumar; T. Jagadeesh Kumar; B. Sreedhar; A. K. Singh; S. K. Srivastava; K. Chandra Sekhar

    2009-01-01

    Tungsten nanoparticles were prepared by thermal decomposition of tungsten hexacarbonyl [W(CO)6] (2mmol) at 160°C in presence of a mixture of (1:1) surfactants, oleic acid (6mmol) and trioctyl phosphine oxide (TOPO) (6mmol) under a blanket of Ar gas. The synthesized tungsten nanoparticles without surfactant are flocculated. With increase in concentration of surfactant mixture to 12mmol each, agglomeration of several tungsten nanoparticles

  5. CCMR: New Iridium Complexes for the Dehydrogenation of Alkanes

    NSDL National Science Digital Library

    Wang, David

    2004-08-17

    To introduce small variations on the previously investigated iridium P-C-P pincer complexes. The variations include substitution of cyclohexyl groups for the tert-butyl and the iso-propyl groups found on the phosphines.Thus, synthesis of these new iridium P-C-P pincer complexes was performed with the aim of improved catalytic dehydrogenation activity as well as a better understand of the influence that ligand sterics and electronics have on the active species.

  6. Identification of oxadiazoles as new drug leads for the control of schistosomiasis

    Microsoft Academic Search

    Ahmed A Sayed; Anton Simeonov; Craig J Thomas; James Inglese; Christopher P Austin; David L Williams

    2008-01-01

    Treatment for schistosomiasis, which is responsible for more than 280,000 deaths annually, depends almost exclusively on praziquantel. Millions of people are treated annually with praziquantel, and drug-resistant parasites thus are likely to evolve. Phosphinic amides and oxadiazole 2-oxides, identified from a quantitative high-throughput screen, were shown to inhibit a parasite enzyme, thioredoxin glutathione reductase (TGR), with activities in the low

  7. The separation of cadmium from zinc with a synergistic mixture of nonylsalicylic acid and triisobutylphosphine sulphide

    Microsoft Academic Search

    Davood Moradkhani; Mark Urbani; Chu Yong Cheng; Masood Askari; Daruosh Bastani

    2005-01-01

    Metal pH50 and ?pH50 values were determined and compared for a number of organic systems to select a synergistic system for the separation of Cd from Zn. The largest ?pH50(Zn–Cd) value was obtained with HRJ-4277 (nonylsalicylic acid)\\/Cyanex 471X (triisobutyl phosphine sulphide or TIBPS) system and reached 1.53 pH units, indicating excellent separation of Cd from Zn with this system. Shellsol

  8. On Cadmium (II) Membrane?Based Extraction using Cyanex 923 as Carrier

    Microsoft Academic Search

    A. M. Sastre; F. J. Alguacil; M. Alonso; F. Lopez

    2008-01-01

    The facilitated transport of cadmium (II) from HCl medium by Emulsion Pertraction Technique (EPERT), using Cyanex 923 (phosphine oxides mixture) as ionophore, is investigated as a function of various experimental variables: hydrodynamic conditions, concentration of cadmium (II) (5–100 mg L) and HCl (0.2–5 M) in the source phase, carrier concentration (5–40% v\\/v) and diluent in the organic phase. A model that describes the

  9. On the Chemical Emergence of Phosphate-Based Biochemistry

    Microsoft Academic Search

    Terence Kee

    2010-01-01

    Contemporary organisms use orthophosphate derivatives (PO43-) in their cell biochemistry,1 yet questions remain as to how Nature was able to accumulate, activate and exploit the or-thophosphate group from geological sources with both poorly solubility and low chemical activ-ity.2 Gulick argued3 a central role for reduced oxidation state phosphorus (P) oxyacids such as H-phosphonates (H2PO3-) and especially H-phosphinates (H2PO2-) in prebiotic

  10. Syntheses and Crystal Structures of Some CCo 3 Clusters Containing PPh 3 or dppm Ligands

    Microsoft Academic Search

    Michael I. Bruce; Kathy A. Kramarczuk; Gary J. Perkins; Brian W. Skelton; Allan H. White; Natasha N. Zaitseva

    2004-01-01

    Molecular structural determinations are reported for six Co3C carbonyl cluster complexes containing tertiary phosphines, which have been isolated as by-products from a variety of reactions. Structural features are similar to those of related complexes already reported. Some discussion of apparent orientational preferences of the CH2 group of dppm ligands, which appear to enter into H-bonding interactions with amido or carboxylate

  11. Rate and mechanism of facilitated americium(III) transport through a supported liquid membrane containing a bifunctional organophosphorus mobile carrier

    Microsoft Academic Search

    P. R. Danesi; E. P. Horwitz; P. G. Rickert

    1983-01-01

    The facilitated transport of Am(III) from aqueous nitrate solutions to formic acid aqueous solutions through a supported liquid membrane (SLM) is described. The supported liquid membrane consists of a solution of a new (carbamoylmethyl)phosphine oxide in diethylbenzene (DEB) absorbed into a 48 ..mu..m thick microporous polypropylene film. The transport mechanism consists of a diffusion process through an aqueous diffusion film,

  12. MINOR ACTINIDE PARTITIONING BY LIQUID–LIQUID EXTRACTION: USING A SYNERGISTIC MIXTURE OF BIS(CHLOROPHENYL)-DITHIOPHOSPHINIC ACID AND TOPO IN A HOLLOW FIBER MODULE FOR AMERICIUM(II)–LANTHANIDES(III) SEPARATION

    Microsoft Academic Search

    Andreas Geist; Michael Weigl; Klaus Gompper

    2002-01-01

    Regarding the difficult selective extraction of trivalent actinides over fission lanthanides from acidic media, we performed several separation tests in hollow fiber modules. Using a synergistic mixture of bis(chlorophenyl)dithiophosphinic acid and tri-n-octyl phosphine oxide in tert-butyl benzene, tests on extraction, lanthanide scrubbing, and stripping were performed. Up to 99.99% americium could be extracted from 0.5 kmol\\/m nitric acid, with approximately one

  13. Synthesis and characterization of fac-[M(CO)3(P)(OO)] and cis-trans-[M(CO)2(P)2(OO)] complexes (M = Re, (99m)Tc) with acetylacetone and curcumin as OO donor bidentate ligands.

    PubMed

    Triantis, Charalampos; Tsotakos, Theodoros; Tsoukalas, Charalampos; Sagnou, Marina; Raptopoulou, Catherine; Terzis, Aris; Psycharis, Vassilis; Pelecanou, Maria; Pirmettis, Ioannis; Papadopoulos, Minas

    2013-11-18

    The synthesis and characterization of neutral mixed ligand complexes fac-[M(CO)3(P)(OO)] and cis-trans-[M(CO)2(P)2(OO)] (M = Re, (99m)Tc), with deprotonated acetylacetone or curcumin as the OO donor bidentate ligands and a phosphine (triphenylphosphine or methyldiphenylphosphine) as the monodentate P ligand, is described. The complexes were synthesized through the corresponding fac-[M(CO)3(H2O)(OO)] (M = Re, (99m)Tc) intermediate aqua complex. In the presence of phosphine, replacement of the H2O molecule of the intermediate complex at room temperature generates the neutral tricarbonyl monophosphine fac-[Re(CO)3(P)(OO)] complex, while under reflux conditions further replacement of the trans to the phosphine carbonyl generates the new stable dicarbonyl bisphosphine complex cis-trans-[Re(CO)2(P)2(OO)]. The Re complexes were fully characterized by elemental analysis, spectroscopic methods, and X-ray crystallography showing a distorted octahedral geometry around Re. Both the monophosphine and the bisphosphine complexes of curcumin show selective binding to ?-amyloid plaques of Alzheimer's disease. At the (99m)Tc tracer level, the same type of complexes, fac-[(99m)Tc(CO)3(P)(OO)] and cis-trans-[(99m)Tc(CO)2(P)2(OO)], are formed introducing new donor combinations for (99m)Tc(I). Overall, ?-diketonate and phosphine constitute a versatile ligand combination for Re(I) and (99m)Tc(I), and the successful employment of the multipotent curcumin as ?-diketone provides a solid example of the pharmacological potential of this system. PMID:24199833

  14. The effect of nanocrystal surface structure on the luminescence properties: Photoemission study of HF-etched InP nanocrystals

    Microsoft Academic Search

    S. Adam; D. V. Talapin; H. Borchert; A. Lobo; C. McGinley; A. R. B. de Castro; M. Haase; H. Weller; T. Möller

    2005-01-01

    InP nanocrystals with narrow size distribution and mean particle diameter tunable from ~2 up to ~7 nm were synthesized via the dehalosilylation reaction between InCl3 and tris(trimethylsilyl)phosphine. Specific capping of the nanocrystal surface with a shell of organic ligands protects the nanocrystals from oxidation and provides solubility of the particles in various organic solvents. InP nanocrystals with enhanced photoluminescence (PL)

  15. Liquid chromatography–electrospray ionisation-mass spectrometry based method for the determination of estradiol benzoate in hair of cattle

    Microsoft Academic Search

    H. Hooijerink; A. Lommen; P. P. J. Mulder; J. A. van Rhijn; M. W. F. Nielen

    2005-01-01

    A liquid chromatography (LC)-based method with mass spectrometric (MS\\/MS) detection was developed for the determination of estradiol benzoate residues in hair of cattle. First hair samples were pulverized with a ball mill followed by treatment with the reducing agent Tris(2-carboxyethyl)phosphine hydrochloride (TCEP). After liquid\\/liquid extraction samples were further purified by solid-phase extraction. Finally samples were analyzed with LC–MS\\/MS using deuterated

  16. Optimisation of a solvent for the complete extraction of prolamins from heated foods

    Microsoft Academic Search

    B. Gessendorfer; H. Wieser; P. Koehler

    2010-01-01

    Wheat bread was lyophilised, ground, extracted and centrifuged. The supernatants were analysed for gluten content by RP-HPLC and a commercial sandwich ELISA. Prolamin extraction solvents contained tris(2-carboxyethyl)phosphine (TCEP; 1, 2, 5, 10, 20, 50mmol\\/L), guanidine hydrochloride (GUA; 0 or 2mol\\/L) and a buffered salt solution. A commercial cocktail solution (250mmol\\/L mercaptoethanol (ME), 2mol\\/L GUA, buffered salt solution) as well as

  17. Protein Refolding System 1 Inclusion body preparation and a 96-well matrix of buffers and

    E-print Network

    Lebendiker, Mario

    inclusion bodies are denatured by addition of TCEP [Tris(2-carboxyethyl)phosphine] and NCl cyclodextrin glycerol TCEP metals cyclodextrin TCEP glycerol 100 mM NaCl TECP PEG6000 100 mM NaCl TCEP GuHCl 100 mM NaCl cyclodextrin TCEP metals 250 mM NaCl cyclodextrin TCEP L-Arg 250 mM NaCl TCEP PEG6000 L

  18. Monitoring of unfolding and refolding in fungal phytase (phyA) by dynamic light scattering

    Microsoft Academic Search

    Abul H. J. Ullah; Kandan Sethumadhavan; Edward J. Mullaney

    2005-01-01

    Role of disulfide bridges in phytase’s unfolding–refolding was probed using dynamic light scattering. Phytase was unfolded by guanidinium chloride and then refolded by removing the denaturant by dialysis. Thiol reagents prevented refolding; thus, disulfide bridge formation is an integral step in phytase folding. Catalytic demise of phytase after unfolding and refolding in presence of Tris(2-carboxyethyl)phosphine (TCEP) indicates that disulfide bridges

  19. Saturation fluorescence labeling of proteins for proteomic analyses

    Microsoft Academic Search

    Elizabeth Pretzer; John E. Wiktorowicz

    2008-01-01

    We present here an optimized and cost-effective approach to saturation fluorescence labeling of protein thiols for proteomic analysis. We investigated a number of conditions and reagent concentrations, including the disulfide reducing agent tris(2-carboxyethyl)phosphine (TCEP), pH, incubation time, linearity of labeling, and saturating dye\\/protein thiol ratio with protein standards to gauge specific and nonspecific labeling. Efficacy of labeling under these conditions

  20. Automated Determination of Hydrogen Peroxide at the Micro-Molar Level in Rainwater and Snow Using a Stopped-Flow Approach in a Hybrid Sequential Injection\\/Flow Injection Manifold

    Microsoft Academic Search

    Paraskevas D. Tzanavaras; Euridiki Boulimari

    2012-01-01

    A new automated method is reported for the determination of H2O2 in real samples. The method is based on the quenching effect of the analyte on the reaction between tris(2-carboxyethyl)phosphine (TCEP) and Ellman's reagent (DTNB). All necessary steps are accomplished under flow conditions using a hybrid sequential injection (SI)\\/flow injection (FI) setup. The sensitivity was enhanced by applying a stopped-flow