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1

The Primary Phosphine Renaissance  

Microsoft Academic Search

\\u000a Primary phosphines are renowned for being toxic, volatile, pyrophoric compounds which have to be handled under an inert atmosphere\\u000a due to their ease of air-oxidation. Thus despite numerous potential applications, they remain underutilized precursors in\\u000a synthetic chemistry. Only a small number of air-stable primary phosphines are known, and their stability is either attributable\\u000a to high steric hindrance about the phosphino

Lee J. Higham

2

Silylated Phosphines and Phosphoranimines  

Microsoft Academic Search

The N-silyl phosphoranimines [e.g., Me3SiN=P(OCH2CF3)Me2] undergo a variety of reactions including deprotonation\\/substitution of the P-Me groups, transilylation, and condensation with reactive phosphines. Some new 1,2-addition and oxidation reactions of the P=C systems, R2NP=CHR, R2NP(=NR)=CHR, and R2NP=CR-CH=CHR (R = SiMe3) are also reported.

Robert H. Neilson; Bruce A. Boyd; Donn A. Dubois; Rahim Hani; Gary M. Scheide; John T. Shore; Urszula G. Wettermark

1987-01-01

3

Allylic phosphinates via palladium-catalyzed allylation of H-phosphinic acids with allylic alcohols.  

PubMed

A novel catalytic allylation of H-phosphinic acids is described. Using Pd/xantphos (2 mol %), H-phosphinic acids react directly with allylic alcohols to produce P-allylated disubstituted phosphinic acids. PMID:18288851

Coudray, Laëtitia; Bravo-Altamirano, Karla; Montchamp, Jean-Luc

2008-02-21

4

The Mutagenic Potential of 4-nitro-phenyl 4-cholorophenyl(methyl)-phosphinate; 4-nitro-phenyl bis(chloromethyl)-phosphinate; 4-nitrophenyl phenyl(trichloromethyl)-phosphinate; 4-nitrophenyl ditrophenyl dichloromethy(phenyl)-phosphinate.  

National Technical Information Service (NTIS)

The mutagenic potential of 4-nitrophenyl 4-chlorophyl(methyl)phosphinate (47B)4-nitrophenyl bis(chloromethyl)phosphinate (16); 4-nitrophenyl phenyl(trichloromethyl)phosphinate (51); 4-nitrophenyl ditrophenyl dichloromethyl(phenyl)phosphinate (77) was asse...

L. J. Sauers F. R. Pulliam J. T. Fruin

1981-01-01

5

Cyclic phosphines as flame retardants  

US Patent & Trademark Office Database

The present invention is related to the use of specific cyclic and/or polymeric aryl-phosphines as flame retardants and to a method for reducing the flammability of organic material by incorporating into the material these specific cyclic and/or polymeric phosphines. Moreover, the invention is related to a polymeric composition containing a polymeric material and at least one of the specific cyclic and/or polymeric phosphines in an amount of from 1 to 15% by weight, based on the weight of the polymeric material. The invention also relates to a composition comprising at least one of the specific cyclic and/or polymeric phosphines and at least one polymerizable monomer.

2013-08-27

6

HUMAN GENOTOXICITY: PESTICIDE APPLICANTS AND PHOSPHINE  

EPA Science Inventory

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

7

Human Genotoxicity: Pesticide Applicators and Phosphine.  

National Technical Information Service (NTIS)

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

V. F. Garry J. Griffith T. J. Danzi R. L. Nelson E. B. Whorton

1989-01-01

8

Synthesis and reactions of phosphine-boranes. Synthesis of new bidentate ligands with homochiral phosphine centers via optically pure phosphine-boranes  

Microsoft Academic Search

Secondary and tertiary phosphine-boranes were synthesized in one-pot from phosphine oxides or substituted chlorophosphines without isolation of the intermediate phosphines. Phosphine-boranes having a methyl group were metalated with sec-butyllithium. The generated carbanions reacted with alkyl halides or carbonyl compounds to yield various phosphine-borane derivatives. A new route to bidentate ligands with homochiral phosphine centers has been explored by utilizing these

Tsuneo Imamoto; Toshiyuki Oshiki; Takashi Onozawa; Tetsuo Kusumoto; Kazuhiko Sato

1990-01-01

9

Phosphine Evolution Control in Red Phosphorus Munitions.  

National Technical Information Service (NTIS)

Several desiccants and sorbents were investigated for reducing or eliminating corrosion in red phosphorus munitions. It was shown that corrosion will not occur in the absence of moisture. Moist air and phosphine from oxyacids corrode the electrical compon...

P. A. Tarantino W. L. Brown

1989-01-01

10

New class of phosphine oxide donor-based supramolecular coordination complexes from an in situ phosphine oxidation reaction or phosphine oxide ligands.  

PubMed

A one-pot, multicomponent, coordination-driven self-assembly approach was used to synthesize the first examples of neutral bridging phosphine oxide donor-based supramolecular coordination complexes. The complexes were self-assembled from a fac-Re(CO)3 acceptor, an anionic bridging O donor, and a neutral soft phosphine or hard phosphine oxide donor. PMID:23984852

Shankar, Bhaskaran; Elumalai, Palani; Shanmugam, Ramasamy; Singh, Virender; Masram, Dhanraj T; Sathiyendiran, Malaichamy

2013-08-28

11

Phosphine photochemistry in Saturn's atmosphere  

NASA Astrophysics Data System (ADS)

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

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

1983-10-01

12

Removal of phosphine contaminant from carbon monoxide gas mixtures  

SciTech Connect

A method is claimed for removing small concentrations of phosphine contained in a carbon monoxide gas mixture by preferentially oxidizing the phosphine, in which the phosphine is oxidized with air at a temperature of from 500 to 800 to form phosphorus pentoxide, which is recovered from the gas mixture preferably as phosphoric acid.

Goldstein, D.; Munday, T.F.; Walden, J.

1980-01-22

13

Poly(phosphine oxides) as supports for enzyme immobilisation  

Microsoft Academic Search

The condensation reactions between tris(hydroxymethyl)phosphine, P(CH2OH)3, and either 1,6-diaminohexane or the trifunctional polyetheramine Jeffamine T-403 produce polymeric aminomethyl phosphines containing excess NH2 groups. These polymers, after oxidation to the phosphine oxides, can be used as supports for enzyme immobilization. Immobilised urease retains activity after continuing usage in urea solutions.

William Henderson; Helen H. Petach; Lea S. Bonnington

1995-01-01

14

Synthesis of tris(organylthioethyl)phosphines and their derivatives on the basis of the reaction of phosphine with vinyl sulfides  

Microsoft Academic Search

Phosphine generated from the red phosphorus in the system KOH-H2O-toluene adds regio- and chemoselectively to vinyl sulfides under radical initiation conditions with the formation of tris(2-organylthioethyl)phosphines,\\u000a which are easily oxidized by elemental sulfur and selenium to the corresponding phosphine sulfides and phosphine selenides\\u000a in 54–78% yield. The obtained adducts are split when treated with sodium amide in THF to give

N. A. Chernysheva; V. L. Mikhailenko; N. K. Gusarova; S. V. Fedorov; B. A. Trofimov

2011-01-01

15

Organophosphorus catalysis to bypass phosphine oxide waste.  

PubMed

The conversion of oxygen-containing compounds is often achieved by the use of phosphorus reagents. The newly formed phosphine oxide bond delivers the enthalpic gain that drives reactions, such as the Wittig, Mitsunobu, and Appel reaction, to completion. However, phosphine oxides are recognized as undesirable waste products and in the past decade several methods have emerged that address this issue by in?situ regeneration of the phosphorus reagent. This Minireview outlines the two distinct strategies and underpinning research that led to these advances. The potential of the emerging field of phosphorus catalysis in chemistry is shown and new developments that may stimulate further research are described. PMID:24039197

van Kalkeren, Henri A; van Delft, Floris L; Rutjes, Floris P J T

2013-09-03

16

COMBATING RESISTANCE TO PHOSPHINE IN AUSTRALIA  

Microsoft Academic Search

Fumigation with phosphine (PH3) is a key component in the management of insect pests in stored grain in Australia. However, the almost exclusive reliance on this chemical has resulted in the development of strong resistance in several major pest species. Since first detecting this problem about three years ago, we have developed a research strategy aimed at combating this resistance.

P. J. COLLINS; G. J. DAGLISH; M. K. NAYAK; P. R. EBERT; D. SCHLIPALIUS; W. CHEN; HERVOIKA PAVIC; TINA M LAMBKIN; ROSEMARY KOPITTKE

2001-01-01

17

Polymeric Chromium (III) Bis(phosphinates).  

National Technical Information Service (NTIS)

General procedures avoiding the use of chromium(II) intermediates are presented for the synthesis of two types of chromium(III) bis(phosphinate) polymers, (Cr(H2O)(OH)(OPRR'O)2)x and (Cr(OH)(OPRR'O2)x. (Author)

H. D. Gillman P. Nannelli B. P. Block

1972-01-01

18

CYTOGENETIC EFFECTS OF PHOSPHINE INHALATION BY RODENTS  

EPA Science Inventory

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

19

Phosphine from rocks: mechanically driven phosphate reduction?  

PubMed

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

Glindemann, Dietmar; Edwards, Marc; Morgenstern, Peter

2005-11-01

20

Reactions of Mono(disilylamino)phosphines with Carbon Tetrachloride.  

National Technical Information Service (NTIS)

A series of mono(disilylamino)phosphines and two related phosphines were treated with CCl4 either neat or in CH2Cl2. The reactions proceeded with elimination of CHCl3 and/or Me3SiCCl3 to form a variety of new P-chloro-N-silylphosphoranimines. The preferen...

R. R. Ford M. A. Goodman R. H. Neilson A. K. Roy U. G. Wettermark

1984-01-01

21

A NEW GENERATION OF FLAME RETARDED POLYAMIDES BASED ON PHOSPHINATES  

Microsoft Academic Search

Polyamide 6 and 66, especially glass fibre reinforced grades, can be effectively fire retarded with a new halogen free product based on an organic phosphinic acid salt. Organic phosphinates are a newly developed class of flame retardants for engineering thermoplastics, and are especially effective for polyamides and polyesters. The chemical registration process in Europe (ELINCS) and US (TSCA) has already

S. Hörold; O. Schacker; W. Wanzke

22

Polytertiary Phosphines and Arsines. III. Metal Complexes of the Tritertiary Phosphine Bis(2-Diphenylphosphinoethyl) Penylphosphine.  

National Technical Information Service (NTIS)

Metal complexes of the tritertiary phosphine ((C6H5)2PCH2CH2)2PC6H5 (abbreviated as (Pf-Pf-Pf)) have been prepared. The infrared spectra, proton nmr spectra, conductances and magnetic susceptibilities of some of these complexes are discussed. (Author)

P. N. Kapoor R. B. King R. N. Kapoor

1971-01-01

23

Phosphine production potential of various wastewater and sewage sludge sources  

SciTech Connect

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

Devai, I.; DeLaune, R.D.; Patrick, W.H. Jr. [Louisiana State Univ., Baton Rouge, LA (United States). Wetland Biogeochemistry Inst.; Devai, G.; Czegeny, I. [Lajos Kossuth Univ., Debrecen (Hungary). Dept. of Ecology

1999-05-01

24

Rhodium(I) acetylacetonato complexes with functionalized phosphines  

Microsoft Academic Search

Rhodium(I) complexes [Rh(acac)(CO)(PR3)] with 1,3,5-triaza-7-phosphatricyclo[3.3.1.13,7]decane (tpa), tris(2-cyanoethyl)phosphine (cyep), tris(3-sodium sulfonatophenyl)phosphine (tppts), tris(o-methoxyphenyl)phosphine (ompp), tris(p-methoxyphenyl)phosphine (pmpp), tris(2,4,6-trimethoxyphenyl)phosphine (tmpp), PPh2(pyl), PPh(pyl)2 and P(pyl)3 (pyl=2-pyridyl) have been synthesized and characterized with 1H- and 31P-NMR and IR spectra. The measured 31P coordination chemical shifts, ??31P{1H}, correlate well with ?(CO). Differences in 1H chemical shifts of methyl groups of acac ligand, ??Me, depend both on

Florian P Pruchnik; Piotr Smole?ski; Katarzyna Wajda-Hermanowicz

1998-01-01

25

Synthesis of a phosphine imide bearing a hydrosilane moiety, and its water-driven reduction to a phosphine.  

PubMed

Organosilanes bearing a phosphine imide moiety were synthesized and crystallographically characterized. Reaction of the pentacoordinated hydrodiphenylsilyl derivative with water gave [2-(diphenylphosphino)phenyl]diphenylsilanol accompanied by both reduction of the phosphine imide moiety and hydrolytic oxidation of the Si-H moiety. PMID:23807626

Kano, Naokazu; Yanaizumi, Kazuhide; Meng, Xiangtai; Havare, Nizam; Kawashima, Takayuki

2013-10-10

26

Reactions of Elemental Phosphorus and Phosphine with Electrophiles in Superbasic Systems: XIV.1 Phosphorylation of 2-Vinylnaphthalene with Elemental Phosphorus and Phosphines in the KOH-DMSO System  

Microsoft Academic Search

Elemental phosphorus (red or white) reacts with 2-vinylnaphthalene while heating at 90-96°C in the superbasic KOH-DMSO system to form 2-(2-naphthyl)ethylphosphine, 2-(2-naphthyl)ethylphosphinic acid, bis[2-(2-naphthyl)ethyl]phosphine, bis[2-(2-naphthyl)ethyl]phosphine oxide, and tris[2-(2-naphthyl)ethyl]phosphine oxide in a total yield of up to 40%. Selective conditions for preparing the tertiary phosphine oxide from white phosphorus and 2-vinylnaphthalene in 58% yield were found. Phosphine and (2-phenylpropyl)phosphine add to 2-vinylnaphthalene

N. K. Gusarova; S. I. Shaikhutdinova; T. I. Kazantseva; S. F. Malysheva; B. G. Sukhov; N. A. Belogorlova; V. I. Dmitriev; B. A. Trofimov

2002-01-01

27

Diiodidobis(triphenyl-phosphine oxide)cadmium  

PubMed Central

In the title compound, [CdI2{(C6H5)3PO}2], the CdII atom is ligated by two I atoms and two O atoms from two triphenyl­phosphine oxide ligands in a disorted tetra­hedral arrangement. While the O—Cd—I angles vary from 106.67?(7) to 111.23?(7)°, the O—Cd—O angle is 88.60?(10)° and the I—Cd—I angle angle is 125.47?(2)°. The crystal structure is stabilized by van der Waals forces only.

Shanthakumari, R.; Hema, R.; Ramamurthy, K.; Stoeckli-Evans, Helen

2011-01-01

28

Phosphine and Jupiter's Great Red SPOT  

NASA Astrophysics Data System (ADS)

Voyager IRIS(Infrared Interferometer Spectrometer) observations of Jupiter's Great Red Spot (GRS) have been examined in order to extract the vertical distribution of phosphine. To the accuracy that can be achieved from this approach, there appears to be no difference between the PH3 distribution over the GRS compared with the distribution over the neighboring South Tropical Zone. This result is at variance with a pre-Voyager prediction of an enhancement of PH3 over the GRS resulting in the preferential production of red phosphorous in this location on the planet (Prinn & Lewis 1975). The composition of the red material remains an open question.

Kim, Sang Joon

1996-06-01

29

Sublethal Exposure to Phosphine Decreases Offspring Production in Strongly Phosphine Resistant Female Red Flour Beetles, Tribolium castaneum (Herbst)  

PubMed Central

The red flour beetle is a cosmopolitan pest of stored grain and stored grain products. The pest has developed resistance to phosphine, the primary chemical used for its control. The reproductive output of survivors from a phosphine treatment is an important element of resistance development but experimental data are lacking. We exposed mated resistant female beetles to 0.135 mg/L of phosphine for 48 h at 25°C. Following one week of recovery we provided two non-exposed males to half of the phosphine exposed females and to half of the non-exposed control females. Females that had been exposed produced significantly fewer offspring than non-exposed females. Females that remained isolated produced significantly fewer offspring than both exposed females with access to males and non-exposed controls (P<0.05). Some females were permanently damaged from exposure to phosphine and did not reproduce even when given access to males. We also examined the additional effects of starvation prior to phosphine exposure on offspring production. Non-exposed starved females experienced a small reduction in mean offspring production in the week following starvation, followed by a recovery in the second week. Females that were starved and exposed to phosphine demonstrated a very significant reduction in offspring production in the first week following exposure which remained significantly lower than that of starved non-exposed females (P<0.05). These results demonstrate a clear sublethal effect of phosphine acting on the female reproductive system and in some individuals this can lead to permanent reproductive damage. Pest population rebound after a fumigation may be slower than expected which may reduce the rate of phosphine resistance development. The results presented strongly suggest that phosphine resistance models should include sublethal effects.

Ridley, Andrew W.; Magabe, Seymour; Schlipalius, David I.; Rafter, Michelle A.; Collins, Patrick J.

2012-01-01

30

Phosphine in paddy fields and the effects of environmental factors.  

PubMed

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±0.6060ngm(-3) to 24.83±6.529ngm(-3) and averaged 14.25±4.547ngm(-3). The highest phosphine emission flux was 22.54±3.897ng(m(2)h)(-1), the lowest flux was 7.64±4.83ng(m(2)h)(-1), and the average flux was 14.17±4.977ng(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 111.6ngkg(-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 10cm 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

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

2013-07-19

31

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

SciTech Connect

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

Harrup, Mason K.; Peterman, Dean R.; Greenhalgh, Mitchell R.; Luther, Thomas A.; Klaehn, John [Idaho National Laboratory, Idaho Falls, ID, 83415 (United States)

2008-07-01

32

Polytertiary Phosphines and Arsines. V. Metal Complexes of a Hexatertiary Phosphine.  

National Technical Information Service (NTIS)

Numerous transition metal complexes of the hexatertiary phosphine 1,1,4,4-tetrakis(2-diphenylphosphinoethyl)-1,4-diphosphabutane ((C6H5)2PCH2CH2)2PCH2CH2P(CH2CH2P)(C6H5)2)2 (abbreviated as P2(-Pf)4) have been prepared. Predominant complex types include th...

M. S. Saran R. B. King

1971-01-01

33

A core metabolic enzyme mediates resistance to phosphine gas.  

PubMed

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

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

34

Hydroxyalkyl phosphine compounds for use as diagnostic and therapeutic pharmaceuticals  

DOEpatents

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.

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

1999-03-02

35

Oxygen Plasma Resistant Phosphine Oxide Containing Imide/Arylene Copolymers.  

National Technical Information Service (NTIS)

A series of oxygen plasma resistant imide/arylene ether copolymers were prepared by reacting anhydride-terminated poly(amide acids) and amine-terminated polyarylene ethers containing phosphine oxide units. Inherent viscosities for these copolymers ranged ...

B. J. Jensen

1993-01-01

36

Ionophilic phosphines: versatile ligands for ionic liquid biphasic catalysis.  

PubMed

Phosphine ligands bearing an imidazolium fragment were easily prepared by one-step radical chain addition of secondary phosphines to allyl or vinyl imidazolium salts. These ligands were used to prepare new ionophilic second generation Grubbs-type catalysts. The catalyst immobilized in 1-butyl-3-methyl imidazolium ILs shows good catalytic activity in RCM reactions of several substrates and, depending on the media employed, is stable up to eight cycles. PMID:18154296

Consorti, Crestina S; Aydos, Guilherme L P; Ebeling, Günter; Dupont, Jaïrton

2007-12-22

37

Molecular Engineering of Zinc Phthalocyanines with Phosphinic Acid Anchoring Groups.  

PubMed

Zinc phthalocyanine sensitizers that contain phosphinic acid anchoring groups have an overall conversion efficiency of 3.24 % under 1 sun in a dye-sensitized solar cell (DSSC). M. K. Nazeeruddin, T. Torres, M. Grätzel, and co-workers demonstrate in their Communication (DOI: 10.1002/anie.201105950) that the phosphinic acid groups provide a stronger binding affinity relative to carboxylic acid anchoring groups, which improves the durability of DSSCs. PMID:22267269

López-Duarte, Ismael; Wang, Mingkui; Humphry-Baker, Robin; Ince, Mine; Martínez-Díaz, M Victoria; Nazeeruddin, Mohammad K; Torres, Tomás; Grätzel, Michael

2012-01-20

38

PHOSPHINE SULPHIDES AND THEIR COMPLEXES WITH METALS: C NMR SPECTROSCOPY  

Microsoft Academic Search

C nuclear magnetic resonance data have been recorded for twenty-two tertiary phosphine sulphides. A discussion of the variation in chemical shifts and P?C coupling constants and a comparison of the data with some analogous phosphine oxides are included. The results are examined with respect to a description of the phosphoryl and thiophosphoryl bonds. The C and H nmr and infra-red

S. Roderick Postle

1977-01-01

39

Zinc(II) and Cobalt(II) Phosphinate Polymers with Low-Temperature Flexibility.  

National Technical Information Service (NTIS)

In developing the scope of tetrahedral metal phosphinate polymers, a variety of groups were introduced on the phosphorus. While many of the phosphinates reported in the past are tractable, those that can be fabricated are brittle, glasslike solids at room...

S. H. Rose B. P. Block

1965-01-01

40

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

Code of Federal Regulations, 2013 CFR

...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...

2013-07-01

41

Responses of phosphate transporter gene and alkaline phosphatase in Thalassiosira pseudonana to phosphine.  

PubMed

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

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

2013-03-27

42

Aluminum phosphinate and phosphates of salen ligands.  

PubMed

A new dealkylation reaction between organophosphate esters and Salen aluminum bromide compounds has been used to prepare three new aluminum salen compounds salen((t)Bu)AlOP(O)Ph2 (1) (salen = N,N'-ethylenebis(3,5-di-tert-butylsalicylideneimine)), [(MeOH)Alsalen((t)Bu)[OMePO2(O)]Alsalen((t)Bu)[OMePO2(O)]Alsalen((t)Bu)]Br (2), and [salpen((t)Bu)AlO]2[(BuO)2PO]2 (3) (salpen = N,N'-propylenebis(3,5-di-tert-butylsalicylideneimine)). Compounds 1.MeOH, 2, and 3 were characterized by single-crystal X-ray diffraction. Compound 1 is the first example of a monomeric aluminum Schiff base phosphinate. Compound 2 is a cationic Salen aluminum phosphate, and compound 3 contains an aluminophosphate ring. This work is the first example of the intentional use of an aluminum-based dealkylation reaction to form new compounds. PMID:16676956

Mitra, Amitabha; Parkin, Sean; Atwood, David A

2006-05-15

43

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

PubMed Central

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

Shapiro, Nathan D.; Toste, F. Dean

2008-01-01

44

Enantioselective aldol reactions catalyzed by chiral phosphine oxides.  

PubMed

The development of enantioselective aldol reactions catalyzed by chiral phosphine oxides is described. The aldol reactions presented herein do not require the prior preparation of the masked enol ethers from carbonyl compounds as aldol donors. The reactions proceed through a trichlorosilyl enol ether intermediate, formed in situ from carbonyl compounds, which then acts as the aldol donor. Phosphine oxides activate the trichlorosilyl enol ethers to afford the aldol adducts with high stereoselectivities. This procedure was used to realize a directed cross-aldol reaction between ketones and two types of double aldol reactions (a reaction at one/two ? position(s) of a carbonyl group) with high diastereo- and enantioselectivities. PMID:23828817

Kotani, Shunsuke; Sugiura, Masaharu; Nakajima, Makoto

2013-07-04

45

Hydrophosphination of propargylic alcohols and amines with phosphine boranes.  

PubMed

The first uncatalyzed hydrophosphinations of propargylic amines and alcohols with phosphine- borane complexes are described. The reactions proceed at ambient temperature or below without the use of protecting groups or the need to handle pyrophoric secondary phosphines, furnishing air-stable phosphineborane-amines and alcohols in good yields. Utilization of chiral propargylic substrates and unsymmetrical secondary phosphineboranes leads to diastereomeric P-chiral products that can be separated by fractional crystallization or chromatography. Initial applications of these new P-X species to asymmetric catalysis are detailed. PMID:23427869

Busacca, Carl A; Qu, Bo; Farber, Elisa; Haddad, Nizar; Gr?t, Nicole; Saha, Anjan K; Eriksson, Magnus C; Wu, Jiang-Ping; Fandrick, Keith R; Han, Steve; Grinberg, Nelu; Ma, Shengli; Lee, Heewon; Li, Zhibin; Spinelli, Michael; Gold, Austin; Wang, Guijun; Wipf, Peter; Senanayake, Chris H

2013-02-21

46

Reactions of Elemental Phosphorus and Phosphine with Electrophiles in Superbasic Media: XI.1 Phosphorylation of 4Methoxybenzyl Chloride with Elemental Phosphorus and Phosphine  

Microsoft Academic Search

4-Methoxybenzyl chloride reacts with elemental (red or white) phosphorus under the conditions of phase-transfer catalysis (concentrated aqueous KOH, dioxane, benzyltriethylammonium chloride, 85-90°C, argon) to give as major product tris(4-methoxybenzyl)phosphine oxide in up to 45% yield. With white phosphorus at lower (70°C) temperature this reaction yields mainly bis(4-methoxybenzyl)phosphine oxide. Phosphine reacts with 4-methoxybenzyl chloride in superbasic KOH-DMSO suspension, and under definite

S. I. Shaikhutdinova; T. I. Kazantseva; N. K. Gusarova; V. I. Dmitriev; B. A. Trofimov

2001-01-01

47

Phosphines Containing the Ch3cf3p Group.  

National Technical Information Service (NTIS)

Volatile phosphines of the new general type CH3CF3PX (where X is a functional group) were made by various methods, including interconversion. The best approach was through addition of CH3I to (CH3)3PPCF3; the resulting methiodide (CH3)3PPCH3CF3(+)I(-) was...

A. B. Burg K. K. Joshi J. F. Nixon

1965-01-01

48

Submicromolar Phosphinic Inhibitors of E. coli Aspartate Transcarbamoylase  

PubMed Central

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

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

2009-01-01

49

POLYIMIDES CONTAINING PENDENT PHOSPHINE OXIDE GROUPS FOR SPACE APPLICATIONS  

Microsoft Academic Search

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

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

50

Photochemistry of phosphine and Jupiter's Great Red SPOT  

Microsoft Academic Search

Results from an experimental investigation of the ultraviolet photolysis of mixtures of phosphine (PH3) in hydrogen are presented. Solid phosphorus was produced by UV irradiation of mixtures of PH3 in hydrogen; the resulting product of this process was always yellow, not red, in color. The indices of refraction of the resulting elemental phosphorus were measured, and the scattering and absorbing

N. Noy; M. Podolak; A. Bar-Nun

1981-01-01

51

Phosphine on Jupiter and implications for the Great Red SPOT  

Microsoft Academic Search

A study of the chemistry and photochemistry of the recently discovered phosphine in the atmosphere of Jupiter suggests that the red colorations on this planet result from photochemical production of red phosphorus particles. Chemical-dynamical models of this red phosphorus haze imply that the intensity of the red coloration is a strong function of the strength of vertical turbulent mixing in

R. G. Prinn; J. S. Lewis

1975-01-01

52

Hydrogenation of nitroarenes using defined iron-phosphine catalysts.  

PubMed

A novel iron-catalyzed hydrogenation of nitroarenes to the corresponding amines is reported. An in situ combination of Fe(BF4)2·6H2O and phosphine allows for highly selective hydrogenation of a broad range of aromatic and nitroarenes tolerating different functional groups. PMID:23928899

Wienhöfer, Gerrit; Baseda-Krüger, Mario; Ziebart, Carolin; Westerhaus, Felix A; Baumann, Wolfgang; Jackstell, Ralf; Junge, Kathrin; Beller, Matthias

2013-08-09

53

Influences of sediment dessication on phosphorus transformations in an intertidal marsh: formation and release of phosphine.  

PubMed

This study investigated the effects of sediment dewatering on the phosphorus transformations concerning about the production and emission of phosphine in the intertidal marsh of the Yangtze Estuary. The concentrations of matrix-bound phosphine ranged from 18.62-72.53 ng kg(-1) and 31.14-61.22 ng kg(-1) within the August and January exposure incubations, respectively. The responses of matrix-bound phosphine concentrations to sediment dessication demonstrate that the production (or accumulation) of matrix-bound phosphine significantly increased with water loss at the start of the emersion incubations. However, further dehydration inhibited the formation of matrix-bound phosphine in sediments. The significant correlations of matrix-bound phosphine with the organic-P bacteria abundance and alkaline phosphatase activities implicate that the production of matrix-bound phosphine within the dessication incubations was linked closely to the microbial decomposition of organic P. The emissions of phosphine generally decreased with sediment dewatering, with the fluxes of 7.51-96.73 ng m(-2)h(-1) and 5.34-77.74 ng m(-2)h(-1) over the exposure incubations of both August and January, respectively. Also, it is observed that the releases of phosphine during the entire exposure periods were affected not only by its production but also by sediment water and redox conditions. PMID:21419470

Hou, Lijun; Liu, Min; Ding, Pingxing; Zhou, Junliang; Yang, Yi; Zhao, Di; Zheng, Yanli

2011-03-17

54

Electrolytic formation of phosphine from red phosphorus in aqueous solutions  

Microsoft Academic Search

Data are presented on the current-voltage behavior of red phosphorus suspensions at gold, platinum, lead, and cadmium cathodes\\u000a in a 1.0 M Na2CO3 solution. In experiments with a red phosphorus suspension in alkaline solutions, the formal current efficiency for phosphine\\u000a was 3–8%, while the current efficiency for hydrogen approached 100%. Similar results were obtained with cathodes produced\\u000a by pressing a

N. N. Shalashova; M. K. Smirnov; S. V. Nikolashin; V. V. Turygin; A. V. Khudenko; M. N. Brekhovskikh; V. A. Fedorov; A. P. Tomilov

2006-01-01

55

Biaryl Phosphine Ligands in Palladium-Catalyzed Amination  

PubMed Central

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

Surry, David S.

2012-01-01

56

Novel second-harmonic-generation-active lead(II) phosphinate based on 2-carboxyethyl(phenyl)phosphinate ligand.  

PubMed

The hydrothermal reaction of PbCl(2) with the achiral 2-carboxyethyl(phenyl)phosphinate ligand (H(2)L) afforded a novel lead(II) phosphinate that contains two enantiomers as a racemic mixture, namely, [Pb(HL)(2)] (?- and ?-1). Each enantiomer features a two-fold symmetrical chiral chain, in which the adjacent Pb(2+) ions are doubly bridged by pairs of HL(-) ligands. The uni-oriented stacking of such 1D chains by edge-to-face ?···? interactions results in its crystallization in the chiral C2 space group. Complex 1 shows a second harmonic generation response that is ?2 times that of KDP (KH(2)PO(4)). PMID:21837351

Sun, Yu-Hui; Xu, Xiang; Du, Zi-Yi; Dong, Li-Jie; Zhao, Cui-Cui; Xie, Yong-Rong

2011-08-12

57

Ruthenium bidentate phosphine complexes for the coordination and catalytic dehydrogenation of amine- and phosphine-boranes.  

PubMed

Addition of the amine-boranes H(3)B?NH(2)tBu, H(3)B?NHMe(2) and H(3)B?NH(3) to the cationic ruthenium fragment [Ru(xantphos)(PPh(3))(OH(2))H][BAr(F)(4)] (2; xantphos=4,5-bis(diphenylphosphino)-9,9-dimethylxanthene; BAr(F)(4)=[B{3,5-(CF(3))(2)C(6)H(3)}(4)](-)) affords the ?(1)-B-H bound amine-borane complexes [Ru(xantphos)(PPh(3))(H(3)B?NH(2)tBu)H][BAr(F)(4)] (5), [Ru(xantphos)(PPh(3))(H(3) B?NHMe(2))H][BAr(F)(4)] (6) and [Ru(xantphos)(PPh(3))(H(3)B?NH(3))H][BAr(F)(4)] (7). The X-ray crystal structures of 5 and 7 have been determined with [BAr(F)(4)] and [BPh(4)] anions, respectively. Treatment of 2 with H(3)B?PHPh(2) resulted in quite different behaviour, with cleavage of the B-P interaction taking place to generate the structurally characterised bis-secondary phosphine complex [Ru(xantphos)(PHPh(2))(2)H][BPh(4)] (9). The xantphos complexes 2, 5 and 9 proved to be poor precursors for the catalytic dehydrogenation of H(3)B?NHMe(2). While the dppf species (dppf=1,1'-bis(diphenylphosphino)ferrocene) [Ru(dppf)(PPh(3))HCl] (3) and [Ru(dppf)(?(6)-C(6)H(5)PPh(2))H][BAr(F)(4)] (4) showed better, but still moderate activity, the agostic-stabilised N-heterocyclic carbene derivative [Ru(dppf)(ICy)HCl] (12; ICy=1,3-dicyclohexylimidazol-2-ylidene) proved to be the most efficient catalyst with a turnover number of 76 h(-1) at room temperature. PMID:21678503

Ledger, Araminta E W; Ellul, Charles E; Mahon, Mary F; Williams, Jonathan M J; Whittlesey, Michael K

2011-06-15

58

Influence of water-soluble sulfonated phosphine ligands on ruthenium catalyzed generation of hydrogen from formic acid  

Microsoft Academic Search

Hydrogen can be generated from formic acid in aqueous phase homogeneous catalytic reactions using ruthenium catalysts with water-soluble phosphine ligands. A comparison of tri-, di-, and mono-sulfonato triphenylphosphine, disulfonato diphenyl-alkyl-phosphines (Ph2PR; R=Me, n-Bu, Cyp), and monosulfonato phenyl-dialkyl-phosphines (PhPR2; R=Me, Cyp) is described. Using two equivalents of water-soluble phosphine per ruthenium ion, significant turnover frequencies are observed for the decomposition of

Weijia Gan; Céline Fellay; Paul J. Dyson; Gábor Laurenczy

2010-01-01

59

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

ERIC Educational Resources Information Center

|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…

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

2007-01-01

60

Inhibition of phospholipase C by isosteric phosphinic acid analogues of lecithin  

Microsoft Academic Search

Four synthetic diether phosphinate analogues of lecithin were studied for inhibitory activity againstClostridium perfringens phospholipase C. An order of inhibitory effectiveness of phosphonate and phosphinate was, thereby, developed. The inhibitions\\u000a seem relatively independent of specific structural features; this is discussed with emphasis on physical effects which complicate\\u000a the inhibition kinetics.

Arthur F. Rosenthal; Sergei V. Chodsky

1974-01-01

61

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

EPA Science Inventory

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

62

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

SciTech Connect

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

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

2000-02-23

63

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

PubMed

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

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

2013-08-01

64

Balancing phosphine in manure fermentation JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH PART B-PESTICIDES FOOD CONTAMINANTS AND AGRICULTURAL WASTES 32 (6): 955-968 1997  

Microsoft Academic Search

The evolution of phosphine gas during the anaerobic batch fermentation of fresh swine manure was detected and correlated to the production of methane and hydrogen sulphide. A close temporal relationship between phosphine liberation and methane formation was found. However, the gaseous phosphine released from manure during fermentation only represents a tiny fraction of the overall phosphine balance. The majority of

F. Eismann; D. Glindemann; A. Bergmann; P. Kuschk

65

Photochemistry of phosphine and Jupiter's great red spot  

SciTech Connect

We present the results of an experimental investigation of the ultraviolet photolysis of mixtures of phosphine in hydrogen. Under no circumstances could red phosphorus be produced in this system. Rather, the product was always yellow. The measured indices of refraction of the phosphorus produced were used to fit the variation of reflectivity of Jupiter's Great Red Spot with wavelength. It was found that the phosphorus particles have to be small (0.05 ..mu..m) and their layer should have an optical depth of about one at lambda = 0.4 ..mu..m.

Noy, N.; Podolak, M.; Bar-Nun, A.

1981-12-20

66

Tribenzyl-chlorido(triphenyl-phosphine oxide-?O)tin(IV)  

PubMed Central

In the title tribenzyl­chloridotin–triphenyl­phosphine adduct, [Sn(C7H7)3Cl(C18H15OP)], the SnIV atom is in a trans-C3SnClO trigonal–bipyramidal geometry and is displaced out of the C3Sn girdle in the direction of the axial Cl atom by 0.112?(1) in one independent mol­ecule and by 0.167?(1)?Å in the other. The phenyl ring of one of the six benzyl units was refined as equally disordered over two sets of sites.

Lo, Kong Mun; Ng, Seik Weng

2011-01-01

67

REACTION OF (SILYLAMINO)PHOSPHINES WITH CARBON DISULFIDE  

Microsoft Academic Search

The (silylamino)phosphines Me3SiN(R)PMe2 (1: R = SiMe3; 2: R = Me) react smoothly with CS2 to yield the zwitterions Me3SiN(R)Me2CS (3: R = SiMe3; 4: R = Me) as red solids. No cleavage of or insertion into P?N or Si?N bonds is observed in these reactions. Compound 3 reacts with MeI to yield the S-methylated phosphonium salt [(Me3Si)2NPMe2C(S)SMe]I (5). Upon

David W. Morton; Robert H. Neilson

1985-01-01

68

Synthesis, characterization and catalytic applications of rhodium(I) organometallics with substituted tertiary phosphines  

Microsoft Academic Search

Organometallics of the type [Rh(COD)(L)Cl] (where, L = carboxyl\\/formyl\\/pyridyl tertiary phosphines) have been synthesized\\u000a by treating the precursor [Rh(COD)Cl]2 with substituted tertiary phosphines. [Rh(COD)(Ph2P-2-C6H4COO)] and [Rh(COD)(Ph2P-CH2COO)] were synthesized by halide abstraction from the precursor [Rh(COD)Cl]2 in the presence of AgPF6 in tetrahydrofuran by involving 2-carboxy phenyl\\/carboxy methyl group of tertiary phosphines in coordination as bidentate\\u000a ligands. Similarly, the cationic compounds of the

Puri Usha Rani; P. Muralidhar Reddy; Kanne Shanker; Vadde Ravinder

2008-01-01

69

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

PubMed

Benzylic alcohols cross-couple directly with concentrated H(3)PO(2) using Pd/xantphos (1 or 2 mol-%). Depending on the substrate, DMF at 110°C, or t-AmOH at reflux with a Dean-Stark trap, can be used. A broad range of benzylic alcohols reacted successfully in moderate to good yields. The preparation of other organophosphorus compounds (phosphinic and phosphonic acids) is also demonstrated.Asymmetric reaction with (R)-1-(2-naphthyl)ethanol provided the corresponding H-phosphinic acid in 77% ee. The methodology provides a green, PCl(3)-free, entry into benzylic-H-phosphinic acids. PMID:23349619

Coudray, Laëtitia; Montchamp, Jean-Luc

2008-08-01

70

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

PubMed Central

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

Queffelec, Clemence; Ribiere, Patrice; Montchamp, Jean-Luc

2009-01-01

71

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

PubMed Central

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

Coudray, Laetitia

2013-01-01

72

Phosphine-Quenching of Cyanine Dyes as a Versatile Tool for Fluorescence Microscopy  

PubMed Central

We report that the cyanine dye Cy5 and several of its structural relatives are reversibly quenched by the phosphine TCEP (tris(2-carboxyethyl)phosphine). Using Cy5 as a model, we show that the quenching reaction occurs by 1,4-addition of the phosphine to the polymethine bridge of Cy5 to form a covalent adduct. Illumination with ultraviolet light dissociates the adduct and returns the dye to the fluorescent state. We demonstrate that TCEP quenching can be used for superresolution imaging as well as for other applications, such as differentiating between molecules inside and outside the cell.

Vaughan, Joshua C.; Dempsey, Graham T.; Sun, Eileen; Zhuang, Xiaowei

2013-01-01

73

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

SciTech Connect

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.

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

2000-04-25

74

Phosphine oxide-catalysed chlorination reactions of alcohols under Appel conditions.  

PubMed

A phosphine oxide-catalysed chlorination reaction of primary and secondary alcohols has been developed. This process represents the first triphenylphosphine oxide-catalysed alcohol chlorination under Appel conditions. PMID:20386856

Denton, Ross M; An, Jie; Adeniran, Beatrice

2010-03-26

75

Catalyzing pyramidal inversion: configurational lability of P-stereogenic phosphines via single electron oxidation.  

PubMed

We report that pyramidal inversion of trivalent phosphines may be catalyzed by single electron oxidation. Specifically, a series of P-stereogenic (aryl)methylphenyl phosphines are shown to undergo rapid racemization at ambient temperature when exposed to catalytic quantities of a single electron oxidant in solution. Under these conditions, transient phosphoniumyl radical cations (R3P(•+)) are formed, and computational models indicate that the pyramidal inversion barriers for these open-shell intermediates are on the order of ?5 kcal/mol. The observed 10(20)-fold rate enhancement over uncatalyzed pyramidal inversion opens new opportunities for the dynamic stereochemistry of phosphines and may hold additional implications for the configurational stability of P-stereogenic phosphine ligands on high-valent oxidizing transition metals. PMID:23745778

Reichl, Kyle D; Ess, Daniel H; Radosevich, Alexander T

2013-06-17

76

Manufacture of Thin-Film Photovoltaic Cells: Characterization and Management of Phosphine Hazards.  

National Technical Information Service (NTIS)

Phosphine is a highly toxic and flammable gas used in thin-film photovoltaic cell manufacturing. Its use can present serious occupational and public health hazards if appropriate prevention and control options are not effectively implemented. This report ...

V. M. Fthenakis P. D. Moskowitz

1986-01-01

77

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

DOEpatents

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.

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

78

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

DOEpatents

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.

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)

2000-01-01

79

Mechanism of Phosphine Dissociation on the Si(001) Surface  

NASA Astrophysics Data System (ADS)

The continued down-scaling of electronic devices to the atomic scale increasingly requires an atomic-level understanding of the elementary processes of semiconductor doping. We present a combined experimental and theoretical investigation into the dissociation mechanism of phosphine (PH3) on the Si(001) surface. As reported by us elsewhere in this conference, a number of prominent intermediate species of PH3 dissociation observed in STM experiments have been structurally characterized as PH2+H, PH+2H and P+3H species respectively. In this poster we present detailed quantum chemical calculations of these and other short-lived intermediates as well as the transition (kinetic) barriers between them. This leads us to formulate a step-by-step mechanism for the complete dissociation of PH3 on the Si(001) surface.

Warschkow, Oliver; Schofield, Steven R.; Smith, Phil V.

2005-03-01

80

Iodidotris(triphenyl-phosphine)copper(I) acetonitrile solvate  

PubMed Central

The title compound, [CuI(C18H15P)3]·C2H3N, was obtained from the reaction of triphenyl­phosphine and copper(I) iodide in acetonitrile. The monomeric form of the complex has slightly distorted coordination of Cu by the I atom and three P atoms. The crystal structure is stabilized by C—H?? inter­actions between phenyl H atoms and phenyl rings. In addition, the complex mol­ecules exhibit C—H?N hydrogen bonds between phenyl H atoms and acetonitrile N atoms. The crystal used was an inversion twin, with nearly equal component populations of 0.522?(8) and 0.478?(8).

Venkatraman, Ramaiyer; Fronczek, Frank R.

2008-01-01

81

Reduction of tertiary phosphine oxides with DIBAL-H.  

PubMed

The reduction of tertiary phosphine oxides (TPOs) and sulfides with diisobutylaluminum hydride (DIBAL-H) has been studied in detail. An extensive solvent screen has revealed that hindered aliphatic ethers, such as MTBE, are optimum for this reaction at ambient temperature. Many TPOs undergo considerable reduction at ambient temperature and then stall due to inhibition. 31P and 13C NMR studies using isotopically labeled substrates as well as competition studies have revealed that the source of this inhibition is tetraisobutyldialuminoxane (TIBAO), which builds up as the reaction proceeds. TIBAO selectively coordinates the TPO starting material, preventing further reduction. Several strategies have been found to circumvent this inhibition and obtain full conversion with this extremely inexpensive reducing agent for the first time. Practical reduction protocols for these critical targets have been developed. PMID:18197688

Busacca, Carl A; Raju, Ravinder; Grinberg, Nelu; Haddad, Nizar; James-Jones, Paul; Lee, Heewon; Lorenz, Jon C; Saha, Anjan; Senanayake, Chris H

2008-01-16

82

Enantioselective cyclizations of silyloxyenynes catalyzed by cationic metal phosphine complexes.  

PubMed

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

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

2012-01-31

83

Photochemistry of phosphine and Jupiter's Great Red SPOT  

NASA Astrophysics Data System (ADS)

Results from an experimental investigation of the ultraviolet photolysis of mixtures of phosphine (PH3) in hydrogen are presented. Solid phosphorus was produced by UV irradiation of mixtures of PH3 in hydrogen; the resulting product of this process was always yellow, not red, in color. The indices of refraction of the resulting elemental phosphorus were measured, and the scattering and absorbing properties of small spheres made of PH3 were computed. The reflectivities of these spheres were then compared with those observed for Jupiter's Great Red Spot. It was found that the phosphorus particles must be small (0.05 microns) and that their layer should have an optical depth of about one at a wavelength of 0.4 microns.

Noy, N.; Podolak, M.; Bar-Nun, A.

1981-12-01

84

Regioselective addition of secondary phosphine oxides to 3-(trialkylsilyl)- and 3-(trialkylgermyl)-2-propynals  

Microsoft Academic Search

3-(Trialkylsilyl)- and 3-(trialkylgermyl)-2-propynals as well as 2-propynal react with secondary phosphine oxides by carbonyl group under mild conditions (?10 to 22°C) to give corresponding tertiary phosphine oxides with acetylenic and hydroxyl moieties in quantitative yield. The reactivity of the aldehydes in this reaction drops in the following order: HC?CC(O)H>Me3SiC?CC(O)H>Et3GeC?CC(O)H.

Nina K Gusarova; Aelita M Reutskaya; Nina I Ivanova; Alevtina S Medvedeva; Maria M Demina; Peter S Novopashin; Andrei V Afonin; Alexander I Albanov; Boris A Trofimov

2002-01-01

85

The mechanism of the phosphine-modified nickel-catalyzed acetic acid process  

Microsoft Academic Search

The nickel-catalyzed methanol (MeOH) carbonylation reaction was studied with an in situ infrared technique using a high pressure cylindrical internal reflectance reactor (CIR-reactor). The role of phosphine ligands was investigated in order to determine the relationship between the structural and electronic properties of the ligand and catalytic properties. It was found that the highest carbonylation rates occurred for the phosphine

William R Moser; Barbara J Marshik-Guerts; Stanley J Okrasinski

1999-01-01

86

Luminescence investigation of the Sm(III)-?-diketonates with sulfoxides, phosphine oxides and amides ligands  

Microsoft Academic Search

In this paper we report on a photoluminescent investigation of complexes involving Sm3+-?-diketonates with sulfoxides, phosphine oxides and amides ligands. In the synthesis of the coordination compounds we used samarium tris(thenoyltrifluoroacetonate) dihydrated precursor with the following ligands (L): DBSO and PTSO sulfoxides; TPPO phosphine oxide and (PHA) N-phenylacetamide. They have shown high orange luminescence characteristic of the Sm3+ ion. The

H. F Brito; O. L Malta; M. C. F. C Felinto; E. E. S Teotonio; J. F. S Menezes; C. F. B Silva; C. S Tomiyama; C. A. A Carvalho

2002-01-01

87

Phosphine-Catalyzed ??-Umpolung Addition of Nucleophiles to Activated ?-Alkyl Allenes  

PubMed Central

Highly functionalized alkenes can be prepared through phosphine-catalyzed ??-umpolung additions of nucleophiles (carbon-, oxygen-, nitrogen-, and sulfur-centered) to activated ?-disubstituted allenes, providing many potentially useful synthetic intermediates in good to excellent yields, often with high levels of stereoselectivity for the product olefin geometry. Various substitution patterns around the allene are compatible with the process, showcasing the synthetic utility of allenes under the conditions of nucleophilic phosphine catalysis.

Martin, Tioga J.; Vakhshori, Venus G.; Tran, Yang S.; Kwon, Ohyun

2011-01-01

88

Room temperature, palladium-mediated P-arylation of secondary phosphine oxides.  

PubMed

We show that a broad range of aryl iodides are efficiently coupled with secondary phosphine oxides using 1 mol % of a catalyst formed in situ from tris(dibenzylideneacetone)dipalladium and Xantphos (1). Scalemic (S)-methylphenylphosphine oxide [(S)-2e] is shown to undergo arylation without detectable stereoerosion. The application of this method to the synthesis of novel P-chiral phosphines and PCP ligands is demonstrated. PMID:22905711

Bloomfield, Aaron J; Herzon, Seth B

2012-08-20

89

CARBAMOYL AND THIOCARBAMOYL DERIVATIVES OF N-BENZYL-AMINOMETHYL-DIMETHYL-PHOSPHINE OXIDE  

Microsoft Academic Search

A series of thirteen new carbamoyl and thiocarbamoyl derivatives of N-benzyl-aminomethyl-dimethyl-phosphine oxide have been synthesized and characterized. The compounds were prepared via interaction of N-benzyl-aminomethyl-dimethyl-phosphine oxide with the corresponding isocyanates or isothiocyanates. The composition of the synthesized novel compounds was proved by elemental analysis for nitrogen and the structures were confirmed by IR,H-, P-P{H} NMR spectroscopy and by mass spectrometry.

Emil Tashev; Viktoria Lachkova; Helmut Keck; Stoycho Shenkov; Wolfgang Kläui; Sabi Varbanov

2004-01-01

90

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

PubMed

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

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

2004-07-01

91

P-C bond formation via P-H addition of a fluoroaryl phosphinic acid to ketones  

PubMed Central

The synthesis, structure and reactivity of the fluoroaryl phosphinic acid HF4C6–P(O)HOH is reported and compared to a sterically comparable yet non-fluorinated analog with similar size. The fluoroaryl phosphinic acid undergoes reversible P–H addition to the carbonyl functionality of ketones under formation of a P–C bond which is retained in the resulting ?-hydroxy phosphinic acid. The latter shows an extended 2D hydrogen bonded network in the solid state.

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

2010-01-01

92

P-C bond formation via P-H addition of a fluoroaryl phosphinic acid to ketones.  

PubMed

The synthesis, structure and reactivity of the fluoroaryl phosphinic acid HF(4)C(6)-P(O)HOH is reported and compared to a sterically comparable yet non-fluorinated analog with similar size. The fluoroaryl phosphinic acid undergoes reversible P-H addition to the carbonyl functionality of ketones under formation of a P-C bond which is retained in the resulting ?-hydroxy phosphinic acid. The latter shows an extended 2D hydrogen bonded network in the solid state. PMID:21072125

Orthaber, Andreas; Albering, Jörg H; Belaj, Ferdinand; Pietschnig, Rudolf

2010-10-01

93

Reactions of Coordinated Ligands. Part 19: 1 Template Synthesis of a Macrocyclic Secondary Tetraphosphine by Oxidative Demetallation of Crown Phosphine Ni(II) Complexes  

Microsoft Academic Search

The nickel(II) complex 3 containing a 14-membered macrocyclic triphosphine phosphinate ligand is obtained by regioselective oxidation of the crown phosphine nickel(II) complex 2c with molecular oxygen. The X-ray structure of 3·H2O (space group P21\\/c) has been determined. Oxidation of the macrocyclic phosphinous acid nickel(II) complex 2a (P4 donor set) with H2O2\\/HCl or Br2 and subsequent demetallation affords the macrocyclic phosphinic

Thomas Lebbe; Peter Machnitzki; Othmar Stelzer; William S. Sheldrick

2000-01-01

94

Tris(2-pyridyl)phosphine oxide: how C-H.O and C-H.N interactions can affect crystal packing efficiency.  

PubMed

Tris(2-pyridyl)phosphine oxide, (I), C(15)H(12)N(3)OP, is isomorphous with tris(2-pyridyl)phosphine. Because of a combination of C-H.O and C-H.N interactions, the crystal packing is denser in the title compound than in the related compounds triphenylphosphine oxide and tris(2-pyridyl)phosphine. PMID:15071228

Bowen, Richard J; Fernandes, Manuel A; Gitari, Patricia W; Layh, Marcus

2004-03-11

95

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

PubMed

The resistance to fumigant insecticides in stored-products insects is often recorded. Several factors influence the evolution of insecticide resistance. Among these, the frequency of applications and the migration of resistant populations are of primary importance for the stored-product insects. The aim of this study was to characterize the spectrum and investigate the status of phosphine resistance in Brazil, in 13 populations of the Coleoptera Tribolium castaneum Herbst (Tenebrionidae), ten populations of Rhyzopertha dominica (Fabr.) (Bostrichidae), and eight populations of Oryzaephilus surinamensis (L.) (Silvanidae). The pattern of resistance dispersion in the populations of these species was also verified. The bioassays for the detection of phosphine resistance followed the FAO standard method. To test the influence of migration in the evolution of the phosphine resistance, the difference of mortality in the discriminating concentration and the geographical distance among each pair wise combination of collection sites were correlated. None of the populations exhibited mortality above 90% in the discriminating concentration, for the three species. Mortality in the discriminating concentration increased with the geographical distance for R.dominica and O.surinamensis. However, no significant linear response was observed among the variables for T.castaneum populations. These results suggest that the dispersion of insects and the local selection are relevant in the evolution of the phosphine resistance in populations of R.dominica and O.surinamensis. In contrast, grain trade and local selection are probably the factors that determine the evolution of the phosphine resistance in populations of T. castaneum. PMID:20305905

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

96

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

NASA Astrophysics Data System (ADS)

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 (PH3) 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.

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

2000-03-01

97

Rhodium Phosphine-?-Arene Intermediates in the Hydroamination of Alkenes  

PubMed Central

A detailed mechanistic study of the intramolecular hydroamination of alkenes with amines catalyzed by rhodium complexes of a biaryldialkylphosphine are reported. The active catalyst is shown to contain the phosphine ligand bound in a ?1, ?6 form in which the arene is ?-bound to rhodium. Addition of deuterated amine to an internal olefin showed that the reaction occurs by trans addition of the N-H bond across the C=C bond, and this stereochemistry implies that the reaction occurs by nucleophilic attack of the amine on a coordinated alkene. Indeed, the cationic rhodium fragment binds the alkene over the secondary amine, and the olefin complex was shown to be the catalyst resting state. The reaction was zero-order in substrate, when the concentration of olefin was high, and a primary isotope effect was observed. The primary isotope effect, in combination with the observation of the alkene complex as the resting state, implies that nucleophilic attack of the amine on the alkene is reversible and is followed by turnover-limiting protonation. This mechanism constitutes an unusual pathway for rhodium-catalyzed additions to alkenes and is more closely related to the mechanism for palladium-catalyzed addition of amide N-H bonds to alkenes.

Liu, Zhijian; Yamamichi, Hideaki; Madrahimov, Sherzod T.; Hartwig, John F.

2011-01-01

98

Determination of impurities in flame retardant monomer 2-carboxyl ethyl(phenyl) phosphinic acid by ion chromotography  

Microsoft Academic Search

In this paper, a method based on ion chromatography (IC) with conductivity detector was developed for the determination of impurities including phenyl phosphinic acid (BPA), phenyl phosphonic acid (PPOA) and crylic acid in flame retardant monomer 2-carboxyl ethyl(phenyl) phosphinic acid (CEPPA). Under favorable chromatographic conditions, good linear relationship, sensitivity and reproducibility were obtained. Detection limits of BPA, PPOA and crylic

Mei-Lan Chen; Wei Yan; Yongxin Chen; Zhishen Jia; Yan Zhu

2007-01-01

99

Phosphine-alkene ligand-mediated alkyl-alkyl and alkyl-halide elimination processes from palladium(II).  

PubMed

N-Diphenylphosphino-7-aza-benzobicyclo[2.2.1]hept-2-ene (2) behaves as a chelating phosphine-alkene ligand for Pd(0) and Pd(II), promoting direct alkyl-alkyl and indirect alkyl-halide reductive elimination reactions due to the stabilisation of the resulting bis(phosphine-alkene)Pd(0) complex. PMID:22986447

Tuxworth, Luke; Baiget, Lise; Phanopoulos, Andreas; Metters, Owen J; Batsanov, Andrei S; Fox, Mark A; Howard, Judith A K; Dyer, Philip W

2012-09-17

100

Palladium-Catalyzed Asymmetric Addition of Diarylphosphines to ?,?-Unsaturated Sulfonic Esters for the Synthesis of Chiral Phosphine Sulfonate Compounds.  

PubMed

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

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

2013-09-19

101

Generation of Phosphide Anions from Phosphorus Red and Phosphine in Strongly Basic Systems to Form Organylphosphines and Oxides  

Microsoft Academic Search

Generation of phosphide anions from phosphorus red or phosphine under the action of strong bases followed by their reactions with organyl halides, electrophilic alkenes and alkynes proves to be the most straightforward and well-controlled route to mono-, di- or triorganylphosphines or phosphine oxides of diverse structure.

Boris Trofimov; Nina Gusarova; Lambert Brandsma

1996-01-01

102

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

PubMed Central

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.

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

2011-01-01

103

Results of TDLS application for ammonia monitoring in a process of high-purity arsine and phosphine production  

NASA Astrophysics Data System (ADS)

Using the TDLS method it has been found that ammonia (NH3) is the main impurity in arsine (AsH3) and phosphine (PH3), produced by hydrolysis of magnesium arsinide and phosphinide, respectively. NH3 behavior is abnormal in solutions of these hydrides: NH3 reveals the properties of a more volatile impurity in relation to arsine and phosphine, although its boiling temperature is higher than that of AsH3 and PH3. The observable anomaly is connected with the fact that in solutions of arsine and phosphine NH3 shows properties differing from the properties of pure ammonia. It was supposed that the influence of intermolecular interaction between ammonia molecules, when diluted by arsine or phosphine, decreases. During the purification of arsine or phosphine one must continuously monitor the NH3.concentration in the extraction of the light fraction in order to define the point at which to terminate the purification process.

Kotkov, A. P.; Ivanov, V. A.; Grishnova, N. D.; Shirayev, A. V.; Berezin, A. G.; Nadezhdinskii, A. I.; Ponurovskii, Y. Y.; Popov, I. P.; Shapovalov, Y. P.; Stavrovskii, D. B.; Vyazov, I. E.

2010-08-01

104

198Au-labeled hydroxymethyl phosphines as models for potential therapeutic pharmaceuticals.  

PubMed

The development of novel gold-198 complexes with water-soluble phosphines is reported. A series of cationic and hydrophilic 198Au complexes containing the ligands tris(hydroxymethyl)phosphine (THP, 1) 1,2-bis[bis(hydroxymethyl)phosphino]benzene (HMPB, 2), and 1,2-bis[bis(hydroxymethyl)phosphino]ethane (HMPE, 3) were prepared and evaluated as models for potential gold-199 radiopharmaceuticals. The 198Au complexes were formed in high radiochemical purity by simply mixing H198AuCl4 with the respective ligand. The complexes were shown to exhibit high in vitro stability over wide pH ranges and temperatures. However, only the 198Au(HMPB)2+ complex was found to exhibit good in vivo stability. HPLC analyses indicated that the 198Au complexes with these three phosphine ligands produced singular species with similar retention times as compared to their known macroscopic complexes. PMID:9751426

Berning, D E; Katti, K V; Volkert, W A; Higginbotham, C J; Ketring, A R

1998-08-01

105

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

PubMed

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

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

2012-08-01

106

The Vertical Structure and Phosphine Distribution on Saturn as Determined by Cassini/VIMS  

NASA Astrophysics Data System (ADS)

We present the preliminary results of our study on the variations of (1) the vertical aerosol layer structure and (2) the phosphine (PH3) distribution on Saturn, utilizing Cassini/VIMS spectral imagery. From the Cassini/VIMS infrared channel spectral data of Saturn acquired in 2004, we sample a dozen pixels at each of the following four latitudes (-10, -27, -47, and -73 degree) to create a set of multi-spectral center-limb profiles for our radiative transfer analysis. We first fit the NIR methane band spectra to determine the altitude of the upper tropospheric haze at the four latitudes, using the newest CH4 near-infrared correlated-k coefficients (Irwin et al. 2006, Icarus, 181, 309-319) and a multi-layer model. This latitudinal variation in the haze altitude is an important clue to unveil Saturn's global climate system. On that basis, we fit the phosphine band spectrum near 3 micron to constrain the phosphine column abundance, using recently published PH3 absorption data sets (Temma et al. 2006, JGR, accepted). Since phosphine is a disequilibrium species in Saturn's upper atmosphere, its increase suggests enhanced convective activity from the deep interior. We thus map the latitudinal phosphine distribution on Saturn, including the analysis of the south polar region where an anomalously strong phosphine absorption was reported (Baines et al. 2005, Earth, Moon, and Planets, 96, 119--147). This work was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA. The first author of this presentation is supported by the NASA Postdoctoral Fellowship at the Jet Propulsion Laboratory.

Temma, T.; Baines, K. H.; Momary, T. W.

2006-12-01

107

The Vertical Structure and Phosphine Distribution on Saturn as Determined by Cassini/VIMS  

NASA Astrophysics Data System (ADS)

We present the preliminary results of our study on the variations of (1) the vertical aerosol layer structure and (2) the phosphine (PH3) distribution on Saturn, utilizing Cassini/VIMS spectral imagery. From the Cassini/VIMS infrared channel spectral data of Saturn acquired in 2004, we sample a dozen pixels at each of the following four latitudes (-10, -27, -47, and -73 degree) to create a set of multi-spectral center-limb profiles for our radiative transfer analysis. We first fit the NIR methane band spectra to determine the altitude of the upper tropospheric haze at the four latitudes, using the newest CH4 near-infrared correlated-k coefficients (Irwin et al. 2006, Icarus, 181, 309-319) and a multi-layer model. This latitudinal variation in the haze altitude is an important clue to unveil Saturn's global climate system. On that basis, we fit the phosphine band spectrum near 3 micron to constrain the phosphine column abundance, using recently published PH3 absorption data sets (Temma et al. 2006, JGR, accepted). Since phosphine is a disequilibrium species in Saturn's upper atmosphere, its increase suggests enhanced convective activity from the deep interior. We thus map the latitudinal phosphine distribution on Saturn, including the analysis of the south polar region where an anomalously strong phosphine absorption was reported (Baines et al. 2005, Earth, Moon, and Planets, 96, 119--147). This work was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA. The first author of this presentation is supported by the NASA Postdoctoral Fellowship at the Jet Propulsion Laboratory.

Temma, Takafumi; Baines, K. H.; Momary, T. W.; Cassini/VIMS Team

2006-09-01

108

Kinetics of phosphine adsorption and phosphorus desorption from gallium and indium phosphide ( 0 0 1 )  

Microsoft Academic Search

The kinetics of phosphine adsorption and phosphorus desorption from gallium and indium phosphide (001) has been determined using reflectance difference spectroscopy to monitor the phosphorus coverage in real time. Assuming a Langmuir adsorption mechanism, phosphine exhibited an initial reactive sticking coefficient at 500 °C of 8.7±1.0×10?2, 3.5±1.0×10?2 and 1.0±0.2×10?3 on the GaP (2×4), GaP (1×1) and InP (2×4) reconstructions, respectively.

Y. Sun; D. C. Law; R. F. Hicks

2003-01-01

109

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

PubMed Central

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.

Andrews, Ian P.

2012-01-01

110

Synthesis and reactivity of a phosphine-stabilized monogermanium analogue of alkynes.  

PubMed

The synthesis of the first isolable C-phosphino-Ge-aminogermyne, stabilized by a phosphine ligand, has been achieved. X-ray diffraction analysis indicates a quite long Ge-C bond whose length is between that of a single and a double bond but consistent with the theoretically predicted values for a germyne bearing ?-donating substituents. The isomerization of this germyne derivative affords a new stable N-heterocyclic germylene through migration of the original phosphine ligand from germanium to the carbon center. PMID:21913709

Berthe, Juliette; Garcia, Juan Manuel; Ocando, Edgar; Kato, Tsuyoshi; Saffon-Merceron, Nathalie; De Cózar, Abel; Cossío, Fernando P; Baceiredo, Antoine

2011-09-20

111

Matrix-bound phosphine and phosphorus fractions in paddy soils.  

PubMed

Phosphine (PH(3)) is a natural gaseous carrier of phosphorus (P) in its geochemical cycles, and it might be important to the P balance of natural ecosystems. Paddy fields are thought to be one of the main sources responsible for the production and emission of PH(3) in to the environment. The relationships between matrix-bound PH(3) (MBP) and different P fractions, as well as selected metals were investigated to explore the possible production of MBP and its link to P cycle in the paddy soils. MBP range from 20.8 (-1) to 502 ng kg(-1) with an average of 145 ng kg(-1). Concentrations at the milk stage are significantly higher than at the jointing stage. The total P range from 333 mg kg(-1) to 592 mg kg(-1). Average P fractions decrease in the order: Ca-P (69.9%) > Organic P (16.5%) > occluded P (6.50%) > Fe-P (5.93%) > dissolved P (0.80%) > exchangeable P (0.32%) > Al-P (0.02%). Different levels of nitrogen fertilizer have little effect on the contents of MBP, P fractions and metals. A significant positive correlation between MBP and Ca-P (p = 0.002), as well as between MBP and Ca (p = 0.008) could be observed, suggesting that Ca-P mainly affects the production of MBP in the paddy soils. It is suggested that soil MBP is strongly linked to Ca-P fertilizer use because soil spiked with P-fertilizer produced an additional 758 ± 142 ng of MBP per kg of soil, compared to only 81.7 ± 12.3 ng of MBP per kg of unspiked soil. No correlations are found between MBP and other P fractions, or between MBP and Al, Fe and Mn. PMID:21359385

Han, Chao; Geng, Jinju; Zhang, Rui; Wang, Xiaorong; Gao, Shixiang

2011-02-28

112

Reactions of Elemental Phosphorus and Phosphine with Electrophiles in Superbasic Systems: XVI. Phosphorylation of Benzyl Chloride with Elemental Phosphorus and Phosphine  

Microsoft Academic Search

The major product of the reaction of benzyl chloride with red phosphorus in the system concentrated aqueous KOH-dioxane-phase-transfer catalyst (43–95°C, Ar) is tribenzylphosphine oxide (yield up to 61%). Under similar conditions, phosphorylation of benzyl chloride with white phosphorus occurs differently, yielding dibenzylphosphine oxide as major product. Conditions are found for preparative synthesis of dibenzylphosphine from phosphine and benzyl chloride in

B. A. Trofimov; N. K. Gusarova; S. F. Malysheva; S. I. Shaikhudinova; N. A. Belogorlova; T. I. Kazantseva; B. G. Sukhov; G. V. Plotnikova

2005-01-01

113

Ditertiary Phosphine Complexes of Nickel. Spectral, Magnetic, and Proton Resonance Studies. A Planar-Tetrahedral Equilibrium.  

National Technical Information Service (NTIS)

A number of complexes of nickel in oxidation states 0, II, and III with the ditertiary phosphines (C6H5)2P(CH2)nP(C6H5)2 (n = 1,2, or 3) are reported and studied by spectral and magnetic methods. In solution in organic solvents complexes of the type Ni ((...

G. R. Van Hecke W. D. Horrocks

1966-01-01

114

Oxidation of phosphine of oxygen catalyzed by copper(II) chloride complexes supported on silica gel  

SciTech Connect

On the basis of kinetic and potentiometric studies, it has been shown that maximum catalytic activity in the oxidation of phosphine by oxygen is manifested by complexes with the composition CuCl/sub 3//sup 1 -/(aq) and CuCl/sub 4//sup 2 -/(aq) supported on MSM silica gel.

Rakitskaya, T.L.; Abramova, N.N.; Poklad, N.S.; Red'ko, T.D.

1988-01-01

115

Asymmetric Total Synthesis of the Iridoid ?-Glucoside (+)-Geniposide via Phosphine Organocatalysis  

PubMed Central

Phosphine catalyzed [3+2] cycloaddition of ethyl-2,3-butadienoate with enone (S)-3b occurs with high levels of regio- and stereocontrol to deliver the cis-fused cyclopenta[c]pyran 4 characteristic of the iridoid family of natural products. Cycloadduct 4 was converted to the iridoid glycoside (+)-geniposide in 10 steps.

Jones, Regan A.; Krische, Michael J.

2010-01-01

116

Phosphine polymerization by nitric oxide: experimental characterization and theoretical predictions of mechanism.  

PubMed

A yellow solid material [P(x)H(y)] has been obtained in the reaction of phosphine (PH(3)) and nitric oxide (NO) at room temperature and characterized by thermogravimetric analysis mass spectrometry (TGA-MS) and attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy. In this work using complete basis set (CBS-QB3) methods a plausible mechanism has been investigated for phosphine polymerization in the presence of nitric oxide (NO). Theoretical explorations with the ab initio method suggest (a) instead of the monomer the nitric oxide dimer acts as an initial oxidant, (b) the resulting phosphine oxides (H(3)P=O <--> H(3)P(+)O(-)) in the gas phase draw each other via strong dipolar interactions between the P-O groups, and (c) consequently an autocatalyzed polymerization occurs among the phosphine oxides, forming P-P chemical bonds and losing water. The possible structures of polyhydride phosphorus polymer were discussed. In the calculations a series of cluster models was computed to simulate polymerization. PMID:19102679

Zhao, Yi-Lei; Flora, Jason W; Thweatt, William David; Garrison, Stephen L; Gonzalez, Carlos; Houk, K N; Marquez, Manuel

2009-02-01

117

REACTIONS OF PHTHALIMIDOBENZOIC ACID AZIDES WITH TRIMETHYL PHOSPHITE AND TRIS (DIALKYLAMINO) PHOSPHINES  

Microsoft Academic Search

Trimethyl phosphite (3a) and\\/or tris (dialkylamino) phosphines (3b, c) react with o-, and m-phthal-imidobenzoic acid azides (1a, b) to give the new iminophosphorane derivatives (4a-4f). Possible reaction mechanism are considered and the structural assignments are based on compatible analytical and spectroscopic results.

Naked K. Eldin

1995-01-01

118

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

DOEpatents

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.

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

1999-01-05

119

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

DOEpatents

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

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

1998-01-01

120

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

DOEpatents

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.

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

1998-12-01

121

Efficient One-Pot Procedures for the Preparation of Secondary Phosphines  

Microsoft Academic Search

Secondary phosphines R2PH or RR'PH (R and R' = alkyl, cycloalkyl) have been obtained in good yields by preparing lithium phosphide from lithium, red phosphorus and t-butylalcohol in liquid ammonia and subsequent alkylation in the presence of alkali amide, prepared in the same flask.

L. Brandsma; N. K. Gusarova; A. V. Gusarov; H. D. Verkruijsse; B. A. Trofimov

1994-01-01

122

A CONVENIENT SYNTHESIS OF TERTIARY PHOSPHINES FROM RED PHOSPHORUS AND ARYL OR HETEROARYLETHENES  

Microsoft Academic Search

Tertiary phosphines (RCH2CH2)3P (R=aryl, heteroaryl) have been obtained in good yields by nucleophilic addition of potassium phosphide, generated from red phosphorus, potassium and t-butanol in liquid ammonia, to aryl- and heteroarylethenes

Lambert Brandsma; Svetlana Arbuzova; Robbert-Jan De Lang; Nina Gusarova; Boris Trofimov

1997-01-01

123

Borane Complexes of the H3PO2 P(III) Tautomer: Useful Phosphinate Equivalents  

PubMed Central

The preparation and reactivity of novel (R1O)(R2O)P(BH3)H [R1, R2 = Et, TIPS] synthons is investigated. The direct alkylation of these compounds with lithium hexamethyldisilazide (LiHMDS) and various electrophiles, provided new series of phosphonite-borane complexes, which can be converted into H-phosphinates and boranophosphonates.

Belabassi, Yamina; Antczak, Monika I.; Tellez, Jennifer

2008-01-01

124

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

PubMed Central

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

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

2012-01-01

125

Synthesis of new secondary phosphine chalcogenides with bulky substituents from aryl(hetaryl)ethenes, red phosphorus, sulfur, and selenium  

Microsoft Academic Search

Phosphine generated along with hydrogen from red phosphorus and aqueous potassium hydroxide selectively reacts with aryl(hetaryl)ethenes\\u000a (?-methylstyrene, 2-vinylnaphthalene and 5-vinyl-2-methylpyridine) in superbasic system KOH-DMSO(H2O) to give secondary phosphines. The latter are practically quantitatively oxidized by elemental sulfur or selenium (20–25°C,\\u000a toluene, 0.5 h), to afford the hitherto unknown secondary phosphine chalcogenides with bulky arylalkyl pyridine and naphthyl\\u000a substituents.

S. F. Malysheva; A. V. Artem’ev; N. K. Gusarova; B. V. Timokhin; A. A. Tatarinova; B. A. Trofimov

2009-01-01

126

Stereoselective synthesis of o-bromo (or iodo)aryl P-chirogenic phosphines based on aryne chemistry.  

PubMed

The efficient synthesis of chiral or achiral tertiary phosphines bearing an o-bromo (or iodo)aryl substituent is described. The key step of this synthesis is based on the reaction of a secondary phosphine borane with the 1,2-dibromo (or diiodo)arene, owing to the formation in situ of an aryne species in the presence of n-butyllithium. When P-chirogenic secondary phosphine boranes were used, the corresponding o-halogeno-arylphosphine boranes were obtained without racemization in moderate to good yields and with ee up to 99%. The stereochemistry of the reaction, with complete retention of the configuration at the P atom, has been established by X-ray structures of P-chirogenic o-halogenophenyl phosphine borane complexes. The decomplexation of the borane was easily achieved without racemization using DABCO to obtain the free o-halogeno-arylphosphines in high yields. PMID:22708733

Bayardon, Jérôme; Laureano, Hugo; Diemer, Vincent; Dutartre, Mathieu; Das, Utpal; Rousselin, Yoann; Henry, Jean-Christophe; Colobert, Françoise; Leroux, Frédéric R; Jugé, Sylvain

2012-06-27

127

A vibration spectroscopic study on the interaction between some sulphide minerals and tris-(2-cyanoethyl)phosphine in aqueous solution  

Microsoft Academic Search

The surfaces of a number of sulphide minerals and synthetic metal sulphides treated with an aqueous solution of tris-(2-cyanoethyl)phosphine have been analysed by means of diffuse reflectance infra-red Fourier transform (DRIFT) spectroscopy. Tris-(2-cyanoethyl)phosphine is chemisorbed through the phosphorus atom to the surfaces of silver(I) sulphide and chalcocite, natural Cu2S, while it is adsorbed through the nitrogen atom(s) to synthetic cadmium

Mats Valli; Bo Malmensten; Ingmar Persson

1995-01-01

128

Preparation of vinyl allenes from 1-lithio-1,3-dienyl phosphine oxides and aldehydes by the Wittig-Horner reaction.  

PubMed

[reaction: see text] Vinyl allenes were prepared in high yields by the Wittig-Horner reaction of 1-lithio-1,3-dienyl phosphine oxides with aldehydes. 1-Lithio-1,3-dienyl phosphine oxides were generated in situ from lithiation of 1-iodo-1,3-dienyl phosphine oxides, which were obtained by iodination of alpha-phosphinozirconacyclopentadienes. As a whole, a vinyl allene is synthesized from two different alkynes and one aldehyde. PMID:16238310

Xi, Zhenfeng; Zhang, Wen-Xiong; Song, Zhiyi; Zheng, Weixin; Kong, Fanzhi; Takahashi, Tamotsu

2005-10-28

129

Chiral phosphine ligands derived from sugars 10. Syntheses, structure, characterization, and antitumor activity of the gold(I) complexes with sugar-substructure phosphine ligands  

Microsoft Academic Search

Gold(I) complexes with sugar-substructure phosphine ligands [Au(n-MBPA)l][n-MBPA = methyl 4,6-O-benzylidene-n-deoxy-n-(diphenylphosphino)-?-d-altropyranoside, HL = I H-pyrimidine-2-thione (2-pymSH), 3,5-dimethyl-1 H-pyrimidine-2-thione (2-pymmSH). 1, n = 2, L = 2-pymS; 2, n = 3, L = 2-pymS; 3, n = 2, L = 2-pymmS; 4, n = 3, L = 2-pymmS]have been prepared and characterized by 1H, 13C and 31P NMR and molecular vibration spectra.

Ji-Cheng Shi; Lin-Ji Chen; Xiao-Ying Huang; Da-Xu Wu; Bei-Sheng Kang

1997-01-01

130

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

NASA Astrophysics Data System (ADS)

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

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

2013-10-01

131

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

PubMed

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

Miyake, Junpei; Watanabe, Masahiro; Miyatake, Kenji

2013-06-28

132

Diphosphine is an intermediate in the photolysis of phosphine to phosphorus and hydrogen  

NASA Astrophysics Data System (ADS)

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

Ferris, J. P.; Benson, R.

1980-05-01

133

Gas Source MBE Growth of High-Quality InP Using Triethylindium and Phosphine  

NASA Astrophysics Data System (ADS)

High-quality InP layers have been grown on (100) InP substrates by gas source molecular beam epitaxy using triethylindium and phosphine as III and V group sources. The electrical and optical properties of grown InP films are evaluated and compared with those of films grown using red phosphorus as a P source. Epitaxial layers are n-type and the highest achieved 77 K mobility is 24000 cm2/Vs with a carrier concentration of 4.1× 1015 cm-3. When phosphine is used instead of red phosphorus as a P source, the compensation ratio (NA/ND) decreases from 0.60-0.98 to 0.29-0.31.

Kawaguchi, Yoshihiro; Asahi, Hajime; Nagai, Haruo

1985-04-01

134

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

SciTech Connect

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

Withnall, R.; Andrews, L.

1987-02-12

135

Metal-Phosphine Bond Strengths of the Transition Metals: A Challenge for DFT  

NASA Astrophysics Data System (ADS)

Previous promising tests of the new M06 family of functionals in predicting ruthenium-metal phosphine bond dissociation energies (Zhao, Y.; Truhlar, D. G. Acc. Chem. Res. 2008, 41, 157) have been extended to a series of phosphine complexes of chromium, molybdenum, nickel, and ruthenium for which relevant experimental data are available. In addition to the M06 family of functionals, bond dissociation enthalpies have been calculated using a selection of density functionals and hybrid functionals based on the generalized gradient approximation (GGA), and with or without an empirical term (i.e., DFT-D) accounting for long-range dispersion. For the ruthenium complexes, second-order Møller-Plesset perturbation theory (MP2) has also been applied. Electrostatic and nonelectrostatic solvent effects have been estimated using the polarizable continuum model (PCM), allowing for comparison with experimental data obtained for dissociation reactions in organic solvents. Whereas the GGA and hybrid-GGA functionals grossly underestimate the absolute metal-phosphine bond enthalpies, with mean unsigned errors (MUEs) for a set of 10 phosphine dissociation reactions in the range 13-27 kcal/mol, the recently developed DFT-based methods for inclusion of attractive noncovalent interactions and dispersion (the DFT-D and M06 functionals) dramatically improve upon the situation. The best agreement with experiment is observed for BLYP-D (MUE = 2.2 kcal/mol), and with the exception for M06-2X, all these methods provide MUEs well below 5 kcal/mol, which should be sufficient for a broad range of applications. The improvements in predicted relative bond enthalpies are less convincing, however. In several cases the GGA and hybrid-GGA functionals are better at reproducing substitution effects than the DFT-D and M06 methods.

Minenkov, Yury; Occhipinti, Giovanni; Jensen, Vidar R.

2009-09-01

136

Hydroformylation of functional alkenes with heterodonor phosphine rhodium catalysts: substrate or ligand directed regioselectivity?  

Microsoft Academic Search

The catalytic activity and selectivity of heterodonor phosphine rhodium catalysts prepared in situ were tested in the hydroformylation of functional alkenes (ethyl acrylate, methyl methacrylate, styrene, 4-vinyl-1-cyclohexene, dicyclopentadiene and cis-1,2,3,6-tetrahydrophthalic anhydride). Systematic variation of the heterodonor atom in the ortho position of the ligand showed that the heterodonor atom has a significant influence on the activities and selectivities of the

H. K. Reinius; A. O. I. Krause

2000-01-01

137

Dimethyl hydrazine-1,2-dicarboxyl-ate-triphenyl-phosphine oxide (1/1)  

PubMed Central

In the crystal structure of the title compound, C4H8N2O4·C18H15OP, two triphenyl­phosphine oxide mol­ecules and two dimethyl hydrazine-1,2-dicarboxyl­ate mol­ecules are connected via N—H?O hydrogen bonds of moderate strength and are related via a twofold rotational axis. Weak Car—H? O contacts strengthen the crystal structure.

Doboszewski, Bogdan; McGarrah, James; Nazarenko, Alexander Y.; da Paixao Soares, Fabio

2011-01-01

138

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

Microsoft Academic Search

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

Syouhei Nishihama; Nobuya Sakaguchi; Takayuki Hirai; Isao Komasawa

2002-01-01

139

High temperature reactions of an aryl–alkyl phosphine, an exceptionally efficient melt stabiliser for polyethylene  

Microsoft Academic Search

Bis(diphenylphosphino)-2,2-dimethylpropane (PMP) is a highly efficient melt stabiliser of polyethylene. This aryl–alkyl phosphine hinders the degradation of the polymer during processing even in small concentrations and in combination with a phenolic antioxidant its consumption rate is considerably slower than that of phosphites and phosphonites. In this study the reactions of PMP were studied at temperatures corresponding to those used for

Gábor Pénzes; Attila Domján; Dóra Tátraaljai; Peter Staniek; Enik? Földes; Béla Pukánszky

2010-01-01

140

The Vertical Structure and Phosphine Distribution on Saturn as Determined by Cassini\\/VIMS  

Microsoft Academic Search

We present the preliminary results of our study on the variations of (1) the vertical aerosol layer structure and (2) the phosphine (PH3) distribution on Saturn, utilizing Cassini\\/VIMS spectral imagery. From the Cassini\\/VIMS infrared channel spectral data of Saturn acquired in 2004, we sample a dozen pixels at each of the following four latitudes (-10, -27, -47, and -73 degree)

T. Temma; K. H. Baines; T. W. Momary

2006-01-01

141

Diphosphine is an intermediate in the photolysis of phosphine to phosphorus and hydrogen  

Microsoft Academic Search

The photolysis of phosphine to red phosphorus (P4) and hydrogen is investigated in light of the potential significance of the reaction in the atmospheric chemistry of Jupiter. It is reported that the photolysis of PH3 at room temperature by a 206.2-nm light source gave rise to a product identified by its UV and IR spectra and gas chromatographic retention time

J. P. Ferris; Robert Benson

1980-01-01

142

Gas Source MBE Growth of High-Quality InP Using Triethylindium and Phosphine  

Microsoft Academic Search

High-quality InP layers have been grown on (100) InP substrates by gas source molecular beam epitaxy using triethylindium and phosphine as III and V group sources. The electrical and optical properties of grown InP films are evaluated and compared with those of films grown using red phosphorus as a P source. Epitaxial layers are n-type and the highest achieved 77

Yoshihiro Kawaguchi; Hajime Asahi; Haruo Nagai

1985-01-01

143

Dimethyl hydrazine-1,2-dicarboxyl-ate-triphenyl-phosphine oxide (1/1).  

PubMed

In the crystal structure of the title compound, C(4)H(8)N(2)O(4)·C(18)H(15)OP, two triphenyl-phosphine oxide mol-ecules and two dimethyl hydrazine-1,2-dicarboxyl-ate mol-ecules are connected via N-H?O hydrogen bonds of moderate strength and are related via a twofold rotational axis. Weak C(ar)-H? O contacts strengthen the crystal structure. PMID:21836978

Doboszewski, Bogdan; McGarrah, James; Nazarenko, Alexander Y; da Paixao Soares, Fabio

2011-06-04

144

Phosphine-catalyzed asymmetric additions of malonate esters to ?-substituted allenoates and allenamides  

PubMed Central

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

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

2010-01-01

145

"On water", phosphine-free palladium-catalyzed room temperature c?h arylation of indoles.  

PubMed

Get on top of your chemistry! An "on water", palladium-catalyzed, phosphine-free direct C?H arylation of indoles, with iodoarenes at 25-30?°C, is disclosed (see scheme; TBDMS=N-tert-butyldimethylsilyl ether; SEM=N-2-(trimethylsilyl)ethoxymethyl; Bn=benzyl, Piv=pivabyl). The mildness of the reaction conditions permits the tolerance of a variety of N1-protected indoles. PMID:24123582

Islam, Saidul; Larrosa, Igor

2013-10-07

146

Unusual structural motif in a zwitterionic Fe(II) complex of a tetradentate phosphine.  

PubMed

The reaction of meso-DPPEPM (DPPEPM = bis(diphenylphosphino-ethylphenylphosphino)methane) with one equivalent of FeBr(2) in tetrahydrofuran generates a zwitterionic compound [FeBr(?(2)-DPPEPM)(?(3)-DPPEPM-FeBr(3))] (1). Compound 1 exhibits an unusual bonding arrangement with two meso-DPPEPM ligands and one bromide coordinated to a single Fe(II) center. One of the DPPEPM ligands binds to iron in a ?(2) mode via two central phosphorus atoms, leaving the terminal phosphines dangling. The second DPPEPM binds through three phosphines, whereas the fourth one coordinates to the iron center of an external FeBr(3)(-) unit. A 1 : 2 reaction of FeBr(2) and meso-DPPEPM in tetrahydrofuran generates [FeBr(?(2)-DPPEPM)(?(3)-DPPEPM)]Br ([2]Br) in which the positive charge on the pseudo-octahedral unit is balanced by free Br(-) as opposed to the phosphine-bound FeBr(3)(-) in 1. The compound [2]PF(6) was obtained from [2]Br and TlPF(6). Solution structures for 1, [2]Br and [2]PF(6) were assigned on the basis of (31)P NMR. For all three compounds the data are consistent with five phosphorus atoms bound to the metal. PMID:22968166

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

2012-11-01

147

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

SciTech Connect

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.

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

2007-11-19

148

High-rate synthesis of phosphine-stabilized undecagold nanoclusters using a multilayered micromixer  

NASA Astrophysics Data System (ADS)

Growth in the potential applications of nanomaterials has led to a focus on the development of new manufacturing approaches for these materials. In particular, an increased demand due to the unique properties of nanomaterials requires a substantial yield of high-performance materials and a simultaneous reduction in the environmental impact of these processes. In this paper, a high-rate production of phosphine-stabilized undecagold nanoclusters was achieved using a layer-up strategy which involves the use of microlamination architectures; the patterning and bonding of thin layers of material (laminae) to create a multilayered micromixer in the range of 25-250 µm thick was used to step up the production of phosphine-stabilized undecagold nanoclusters. The continuous production of highly monodispersed phosphine-stabilized undecagold nanoclusters at a rate of about 11.8 (mg s - 1) was achieved using a microreactor with a size of 1.687 cm3. This result is about 500 times over conventional batch syntheses based on the production rate per reactor volume.

Jin, Hyung Dae; Garrison, Anna; Tseng, T.; Paul, Brian K.; Chang, Chih-Hung

2010-11-01

149

High-rate synthesis of phosphine-stabilized undecagold nanoclusters using a multilayered micromixer.  

PubMed

Growth in the potential applications of nanomaterials has led to a focus on the development of new manufacturing approaches for these materials. In particular, an increased demand due to the unique properties of nanomaterials requires a substantial yield of high-performance materials and a simultaneous reduction in the environmental impact of these processes. In this paper, a high-rate production of phosphine-stabilized undecagold nanoclusters was achieved using a layer-up strategy which involves the use of microlamination architectures; the patterning and bonding of thin layers of material (laminae) to create a multilayered micromixer in the range of 25-250 µm thick was used to step up the production of phosphine-stabilized undecagold nanoclusters. The continuous production of highly monodispersed phosphine-stabilized undecagold nanoclusters at a rate of about 11.8 (mg s(-1)) was achieved using a microreactor with a size of 1.687 cm(3). This result is about 500 times over conventional batch syntheses based on the production rate per reactor volume. PMID:20935355

Jin, Hyung Dae; Garrison, Anna; Tseng, T; Paul, Brian K; Chang, Chih-Hung

2010-10-08

150

Phosphine and phosphonite complexes of a Ru(II) porphyrin. 2. Photophysical and electrochemical studies.  

PubMed

The photophysical and electrochemical properties of a series of mono- and bis-phosphine complexes of a 5,15-diphenyl-substituted ruthenium porphyrin, (MeOH)Ru(II)(CO)(DPP) 1, were investigated. The ligands used were diphenyl(phenylacetenyl)phosphine (DPAP), diethyl (phenylacetenyl)phosphonite [PAP(OEt)(2)], tris(phenylacetenyl)phosphine [(PA)(3)P], and bis(diphenylphosphino)acetylene (DPPA). All complexes display two reversible one-electron oxidations at: 0.61 and 1.0 V vs SCE (1), 0.42-0.51 and 0.97-1.05 V [(PR(3))Ru(II)(CO)(DPP)], and 0.06-0.25 and 0.82-0.95 V [(PR(3))(2)Ru(II)(DPP)]. As predicted by EHMO calculations, the first oxidation is porphyrin or phosphorus centered, whereas the second one is ruthenium centered. Bulk electrolysis at the first oxidation potential yields stable monocations. Simulation of the cyclic voltammogram of (DPAP)Ru(II)(CO)(DPP) in CH(2)Cl(2) demonstrates the kinetic lability of the complex, and the association constant found (K = 1.27 x 10(6) M(-1)) is in accordance with the value determined by UV-vis titration (K = 1.2 +/- 0.3 x 10(6) M(-1)). Coordination of one phosphine ligand to Ru(II)(CO)(DPP) leads to a red shift in both the absorption and luminescence spectra. Shifts are typically 10 nm for the B- and Q-band absorptions and are not affected by the nature of the phosphorus ligand. The intense luminescence of (PR(3))Ru(II)(CO)(DPP), red-shifted by 21-28 nm compared to 1, can be attributed to originate from a (3)(pi,pi) excited state, and it exhibits lifetimes from 150 to 240 micros. In the bis-phosphine complexes (PR(3))(2)Ru(II)(DPP), the Q-band absorption is broadened and does not show any distinct peak. Judged from EHMO calculation, this could arise from a low-energy charge-transfer state involving the phosphorus ligand. The luminescence is efficiently quenched due to radiationless decay from a charge-transfer excited state, involving either the metal center or the phosphorus ligand; an unambiguous assignment could not be made. PMID:12354061

Stulz, Eugen; Sanders, Jeremy K M; Montalti, Marco; Prodi, Luca; Zaccheroni, Nelsi; Fabrizi de Biani, Fabrizia; Grigiotti, Emanuela; Zanello, Piero

2002-10-01

151

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

PubMed

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

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

2011-09-09

152

Triethylborane-initiated room temperature radical addition of hypophosphites to olefins: synthesis of monosubstituted phosphinic acids and esters.  

PubMed

A novel and practical approach to monosubstituted phosphinic acid (alkylphosphonous acid) derivatives from hypophosphite salts or esters is described. Phosphorus-centered radical formation is initiated with Et(3)B/O(2), and the reaction is conveniently conducted at room temperature in an open flask. In contrast to previously reported conditions for the radical reaction of hypophosphorous acid and sodium hypophosphite (peroxide initiators, acid catalysis, heat), the method proceeds under neutral conditions and therefore tolerates a wide range of functional groups. Previously inaccessible phosphinic acids can be prepared in a single step from cheap starting materials. Excellent selectivity is observed for monoaddition, and symmetrical dialkyl phosphinates do not form in significant amounts. Monosubstituted phosphinic acids are usually obtained in better than 90% purity by a simple extractive workup; however, isolated yields are diminished if the substituent is polar. Because radicals derived from hypophosphites are electrophilic, the reaction is limited to the use of electron-rich olefins. The reaction conditions can also be employed in the room temperature radical reduction of alkyl halides and provide an exceptionally mild and environmentally friendly alternative to the use of tributyltin hydride. The remarkable mild nature of the reaction conditions allows for the radical reaction of sensitive alkyl hypophosphites to occur, in which case, a catalytic amount of Et(3)B suffices to deliver alkyl phosphinate esters in reasonable yield. PMID:11578230

Deprèle, S; Montchamp, J L

2001-10-01

153

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

PubMed

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

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

2013-08-21

154

Novel synthesis of 2-Substituted 19-norvitamin D A-ring phosphine oxide from d-glucose as a building block  

Microsoft Academic Search

19-Norvitamin D A-ring phosphine oxide 5 was synthesized by a new sequence mode starting from d-glucose as a chiral template. Transformation of the pyranoside ring into the A-ring carbocycle was achieved by the Pd-catalyzed Ferrier rearrangement. The phosphine oxide 5 was obtained in an 18% overall yield by this novel cost-effective method.

Masato Shimizu; Yukiko Iwasaki; Yoshinori Shibamoto; Miki Sato; H. F DeLuca; Sachiko Yamada

2003-01-01

155

Rapid synthesis of an electron-deficient t-BuPHOX ligand: cross-coupling of aryl bromides with secondary phosphine oxides  

PubMed Central

Herein an efficient and direct copper-catalyzed coupling of oxazoline-containing aryl bromides with electron-deficient secondary phosphine oxides is reported. The resulting tertiary phosphine oxides can be reduced to prepare a range of PHOX ligands. The presented strategy is a useful alternative to known methods for constructing PHOX derivatives.

McDougal, Nolan T.; Streuff, Jan; Mukherjee, Herschel; Virgil, Scott C.; Stoltz, Brian M.

2010-01-01

156

Influence of phosphine on hatching of Cryptolestes ferrugineus (Coleoptera: Cucujidae), Lasioderma serricorne (Coleoptera: Anobiidae) and Oryzaephilus surinamensis (Coleoptera: Silvanidae).  

PubMed

The hatching and mortality response of 0- to 48-h-old eggs of field strains of the stored-product insects Cryptolestes ferrugineus (Stephens), Lasioderma serricorne (F) and Oryzaephilus surinamensis (L) following phosphine fumigation for 24, 48 or 120 h at 27 (+/- 2) degrees C was investigated. Hatching was delayed and reduced in the first few days in a phosphine-resistant strain of C ferrugineus that was treated with 2.0-7.0 mg litre(-1) doses for 48 h (5-80% mortality) and with 1.0-2.0 mg litre(-1) for 120 h (44-84% mortality). In both the exposures there were significant increases in hatching on later days when compared with the corresponding controls. Developmental delay was, however, not evident in susceptible strains of C ferrugineus, L serricorne and O surinamensis that were exposed to phosphine for 24 h. PMID:15532686

Rajendran, Somiahnadar; Parveen, Hajira; Begum, Khamrunissa; Chethana, Ramesh

2004-11-01

157

Reactions of Elemental Phosphorus and Phosphine with Electrophiles in Superbasic Systems: XV. Phosphorylation of Allyl Halides with Elemental Phosphorus  

Microsoft Academic Search

Elemental phosphorus (red or white) reacts with allyl chloride and allyl bromide in a two-phase system aqueous KOH-organic solvent to form tertiary symmetrical and mixed phosphine oxides among which tris(prop-2-enyl)-, bis(prop-2-enyl)[(E)-prop-1-enyl]-, bis(prop-2-enyl)[(Z)-prop-1-enyl]-, (prop-2-enyl)[(E)-prop-1-enyl][(Z)-prop-1-enyl]-, bis[(E)-prop-1-enyl](prop-2-enyl)-, bis[(Z)-prop-1-enyl](prop-2-enyl)-, tris-[(E)-prop-1-enyl]-, and bis[(E)-prop-1-enyl][(Z)-prop-1-enyl]phosphine oxides were identified. The conditions (room temperature, 60% aqueous KOH-dioxane) allowing preparation from white phosphorus and allyl bromide of tris(prop-2-enyl)- and bis(prop-2-enyl)[(E)-prop-1-enyl]phosphine

S. F. Malysheva; B. G. Sukhov; N. K. Gusarova; A. V. Afonin; S. I. Shaikhudinova; T. I. Kazantseva; N. A. Belogorlova; V. A. Kuimov; G. V. Plotnikova; B. A. Trofimov

2004-01-01

158

Photophysical Properties of Endohedral Amine-Functionalized Bis(phosphine) Pt(II) Complexes as Models for Emissive Metallacycles.  

PubMed

The photophysical properties of bis(phosphine) Pt(II) complexes constructed from 2,6-bis(pyrid-3-ylethynyl) aniline and 2,6-bis(pyrid-4-ylethynyl) aniline vary significantly, even though the complexes differ only in the position of the coordinating nitrogen. By capping the ligands with an aryl bis(phosphine) Pt(II) metal acceptor, the photophysical properties of the two isomeric systems were directly compared, revealing that the low-energy absorption and emission bands of the two systems were separated by 30 nm (1804 cm(-1)) and 39 nm (1692 cm(-1)), respectively. From the analysis of time-dependent density functional (TD-DFT) calculations and excited-state lifetime measurements, it was determined that the nature of the Pt-N bond in the HOMO and the sums of the radiative (krad) and nonradiative (knr) rate constants were significantly different in the two systems. As the dominant nonradiative decay pathway in aniline systems is relaxation from the triplet state through intersystem crossing (ISC), the difference in knr can be ascribed to changes in ISC between isomers of the bis(phosphine) Pt(II)-capped 2,6-bis(pyrid-3-ylethynyl) aniline system. It was also determined that the photophysical properties of these capped systems can be altered by functionalizing the aryl capping ligand on the bis(phosphine) Pt(II) metal center, which perturbs the molecular orbitals involved in the observed optical transitions. In addition, an isoelectronic bis(phosphine) Pd(II)-capped system was prepared for comparison with the bis(phosphine) Pt(II) suite of complexes. The Pd(II) system showed significant changes in its low-energy absorption band, but preserved the characteristic emissive properties of its Pt(II) analogue with an even higher quantum yield. PMID:23909761

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

2013-08-02

159

New water-soluble phosphines as reductants of peptide and protein disulfide bonds: reactivity and membrane permeability.  

PubMed

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 TCEP were synthesized to evaluate the role of carboxylate anions in the reduction mechanism, and to expand the range of phosphine reductants. The effectiveness of all four phosphines relative to DTT has been determined using model disulfides, including a fluorescent disulfide-containing peptide (H(3)N(+)-VTWCGACKM-NH(2)), and with protein disulfide bonds in thioredoxin and sulfhydryl oxidase. Mono-, di-, and trimethyl esters exhibit phosphorus pK values of 6.8, 5.8, and 4.7, respectively, extending their reactivity with the model peptide to correspondingly lower pH values relative to that of TCEP (pK = 7.6). At pH 5.0, the order of reactivity is as follows: trimethyl- > dimethyl- > monomethyl- > TCEP > DTT; tmTCEP is 35-fold more reactive than TCEP, and DTT is essentially unreactive. Esterification also increases lipophilicity, allowing tmTCEP to penetrate phospholipid bilayers rapidly (>30-fold faster than DTT), whereas the parent TCEP is impermeant. Although more reactive than DTT toward small-molecule disulfides at pH 7.5, all phosphines are markedly less reactive toward protein disulfides at this pH. Molecular modeling suggests that the nucleophilic phosphorus of TCEP is more sterically crowded than the thiolate of DTT, contributing to the lower reactivity of the phosphine with protein disulfides. In sum, these data suggest that there is considerable scope for the synthesis of phosphine analogues tailored for specific applications in biological systems. PMID:15568811

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

2004-12-01

160

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

PubMed

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

Lim, Sang Ho; Cohen, Seth M

2013-06-25

161

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

PubMed

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

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

2007-01-01

162

Phosphine catalyst-controlled cycloaddition or dienylation reactions of trifluoromethyl aryl ketones with bis-substituted allenoates.  

PubMed

A chemoselective phosphine-catalyzed cycloaddition or dienylation reaction between trifluoromethyl-substituted ketones and bis-substituted allenoates was described. Under the catalysis of triarylphosphine, the reaction gave a range of trifluoromethylated tetrahydrofurans with broad substrate tolerance and good to excellent stereoselectivity, while the use of trialkylphosphine switched the reaction pathway to furnish CF3-substituted dienyl tertiary alcohols chemoselectively. Moreover, a preliminary study on the asymmetric version of the reaction was also performed, which represents the first example of a phosphine-catalyzed asymmetric reaction between allenoates and carbonyl compounds. PMID:24010962

Xiao, Hua; Chai, Zhuo; Yao, Ri-Sheng; Zhao, Gang

2013-09-19

163

Effects of the adsorption characteristics of a carbon-fiber material on the activity of a phosphine oxidation catalysts  

SciTech Connect

The specimens were made from microporous carbon fiber material having various static activity as determined from the sorption of benzene vapor. It was shown that the porous structure is extended at the expense of increase in the micropore volume, which remains almost constant. The specimens were tested in flowing gas with a thermostatic system. Results presented as graphs reflected the phosphine concentration at the exit. Tables indicate that copper (II) and chloride reduces the static activity considerably. The effects of relative water vapor pressure on the uptake in sorption and catalysts performance in the oxidation of phosphine are presented.

Rakitskaya, T.L.; Litvinskaya, V.V.; Abramova, N.N.; Red'ko, T.D.; Popova, N.A.

1987-12-01

164

Reactions of elemental phosphorus and phosphine with electrophiles in superbasic systems: XX. Phosphorylation of 4-vinylbenzyl chloride with elemental phosphorus  

Microsoft Academic Search

4-Vinylbenzyl chloride reacts with white and red phosphorus, as well as with nanostructured “activated” red phosphorus (complex\\u000a organophosphorus polymer prepared from white phosphorus under ionizing radiation) in the system concentrated aqueous KOH-dioxane-phase-transfer\\u000a catalyst (20–50°C, argon) to form tris(4-vinylbenzyl)phosphine oxide, along with (4-vinylbenzyl)- and bis(4-vinylbenzyl)phosphinic\\u000a acids, the yield and product ratio being dependent on both the reaction conditions and the nature

S. F. Malysheva; V. A. Kuimov; N. K. Gusarova; B. G. Sukhov; Yu. V. Smetannikov; N. P. Tarasova; B. A. Trofimov

2007-01-01

165

A gold(I) phosphine complex selectively induces apoptosis in breast cancer cells: Implications for anticancer therapeutics targeted to mitochondria  

Microsoft Academic Search

Bis-chelated gold(I) phosphine complexes have shown great potential as anticancer agents, however, their efficacy has been limited by their high toxicity and lack of selectivity for cancer cells. Here, we have investigated the anticancer activity of a new bis-chelated Au(I) bidentate phosphine complex of the novel water soluble ligand 1,3-bis(di-2-pyridylphosphino)propane (d2pypp). We show that this gold complex [Au(d2pypp)2]Cl, at submicromolar

Oliver Rackham; Scott J. Nichols; Peter J. Leedman; Susan J. Berners-Price; Aleksandra Filipovska

2007-01-01

166

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

NASA Astrophysics Data System (ADS)

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

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

2012-08-01

167

Nonlinear optical absorption in the blue spectral region by phosphine-substituted oligothiophenes  

NASA Astrophysics Data System (ADS)

Organic conjugated materials with large nonlinear optical (NLO) absorption have potential applications in optical computing, optical switching and optical power limiting. However, nearly all investigations have focused on the green, red and near-infrared regions of the optical spectrum. In contrast, organic conjugated materials exhibiting NLO absorption in the blue region have not been reported. Phosphine-substituted oligothiophenes are among the few materials that exhibit nonlinear optical absorption in the blue spectral region. Three families of these materials have been investigated, and the best blue absorber at 430 nm is 5,5'-bis(diphenylphosphine selenide)-2,2'-bithiophene.

Wang, Jianwei; Lawson, Christopher; Zhao, Qun; Gray, Gary

2009-11-01

168

Phosphine migration at the water–air interface in Lake Taihu, China  

Microsoft Academic Search

The diurnal atmospheric phosphine (PH3) concentrations and fluxes at the water–air interface in Lake Taihu were reported. The results showed that the PH3 flux at the water–air interface ranged from ?69.9±29.7 to 121±42ngm?2h?1, with a mean flux of 14.4±22.5ngm?2h?1. The fluxes were both negative and positive during the diurnal period, indicating that the lake can act as a sink and

Chao Han; Jinju Geng; Juan Zhang; Xiaorong Wang; Shixiang Gao

2011-01-01

169

One step synthesis of a new asymmetric water-soluble phosphine  

Microsoft Academic Search

The new asymmetric water-soluble phosphine (S)-(?)-(3-diphenylphosphino-2-hydroxypropyl)trimethylammonium chloride was synthesised from the accessible (S)-(?)-(3-chloro-2-hydroxypropyl)trimethylammonium chloride by means of a one pot reaction between this ionic compound and sodium diphenylphosphide in liquid ammonia. The palladium complex (L)PdCl3 (L=(S)-(?)-(3-diphenylphosphino-2-hydroxypropyl)trimethylammonium) was prepared by reaction between this ligand and PdCl2(PhCN)2 and was characterised by spectroscopic methods.

Mireia Condom; Joan Suades

2005-01-01

170

Tris(thio-cyanato-?N)tris-(triphenyl-phosphine oxide-?O)terbium(III)  

PubMed Central

The title compound, [Tb(NCS)3(C18H15OP)3], contains a six-coordinate TbII cation surrounded by three O-bound triphenyl­phosphine oxide ligands and three N-bound thio­cyanate ligands, each in a fac arrangement. There are two crystallographically unique TbIII atoms in the asymmetric unit. One TbIII atom resides on a threefold rotation axis, while the other has no imposed crystallographic symmetry. The thio­cyanate ligands are bound through N atoms, illustrating the hard–hard bonding principles of metal complex chemistry.

Pham, Lam N.; Thames, Anthony T.; White, Frankie D.; Xiang, Kang Rui; Sykora, Richard E.

2012-01-01

171

High capacity CO2 adsorption in a Mg(II)-based phosphine oxide coordination material.  

PubMed

The new porous phosphine coordination material, PCM-11, is an unusual 8,4-connected coordination polymer with an open 3-D pore structure, formed by reaction of Mg(II) with tris(para-carboxylato)triphenylphosphine oxide. The highly ionic nature of the metal-ligand bonding results in excellent thermal stability upon desolvation (>460 °C). PCM-11 is easily activated for small molecule sorption at low temperature without the requirement for solvent pre-exchange. It adsorbs 47.5 wt% CO(2) at 11.6 bar and 30 °C. PMID:21442086

Bohnsack, Alisha M; Ibarra, Ilich A; Hatfield, Peter W; Yoon, Ji Woong; Hwang, Young Kyu; Chang, Jong-San; Humphrey, Simon M

2011-03-25

172

(Fluoroalkyl)phosphine complexes of nickel(0) and cobalt(I)  

Microsoft Academic Search

The synthesis of a series of (fluoroalkyl)phosphine complexes of nickel is reported. Treatment of (cod)2Ni with dfepe (dfepe=(C2F5)2PCH2CH2P(C2F5)2) yields (dfepe)Ni(cod) (1), which has been structurally characterized. Treatment of 1 with CO or bipy results in the formation of (dfepe)Ni(CO)2 (2) and (dfepe)Ni(bipy) (3), respectively. Addition of excess dfepe to 1 results in incomplete cod displacement to form (dfepe)2Ni (4). The

Byron L. Bennett; Shannon White; Brittany Hodges; Dane Rodgers; Ade Lau; Dean M. Roddick

2003-01-01

173

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

PubMed Central

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

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

2012-01-01

174

trans-Dichloridobis[tris-(2-methoxy-phen-yl)phosphine]palladium(II)  

PubMed Central

The structure of the title compound, [PdCl2(C21H21O3P)2], shows a nearly square-planar geometry for the PdII atom within the Cl2Pd[P(PhOMe)3]2 ligand set. The PdII atom sits on a centre of inversion and therefore the asymmetric unit contains one half-mol­ecule, i.e. half of one PdII atom, one Cl atom and one tris­(2-methoxy­phen­yl)phosphine ligand.

van Blerk, Charmaine; Holzapfel, Cedric W.

2009-01-01

175

trans-Bis[bis-(2-methoxy-phen-yl)phenyl-phosphine-?P]dichloridopalladium(II)  

PubMed Central

The structure of the title compound, [PdCl2(C20H19O2P)2], shows a square-planar geometry for the PdII ion within a Cl2Pd[PPh(PhOMe)2]2 ligand set. The PdII atom sits on an inversion centre and therefore the asymmetric unit contains the PdII atom, one Cl atom and one bis­(2-methoxy­phen­yl)phenyl­phosphine ligand. The trans arrangement of ligands is also imposed by symmetry.

van Blerk, Charmaine; Holzapfel, Cedric W.

2009-01-01

176

trans-Dichloridobis[tris-(4-methoxy-phen-yl)phosphine]palladium(II) benzene monosolvate  

PubMed Central

The structure of the title compound, [PdCl2(C21H21O3P)2]·C6H6, shows a square-planar geometry for the PdII atom within a Cl2[P(PhOMe)3]2 ligand set. The crystal structure contains benzene as solvent. The PdII atom sits on a centre of inversion and therefore the asymmetric unit contains the PdII atom, one Cl atom, one tris­(4-methoxy­phen­yl)phosphine ligand and one half of the benzene solvent mol­ecule.

van Blerk, Charmaine; Holzapfel, Cedric W.

2009-01-01

177

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

Microsoft Academic Search

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

Yukio Nagaosa; Yao Binghua

1997-01-01

178

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

DOEpatents

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.

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

1989-10-17

179

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

DOEpatents

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.

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

1989-01-01

180

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

PubMed

On December 10, 2009, a fumigation stack containing aluminum phosphide became soaked with rain water and caught fire at a pistachio processing plant in Kern County, California. Untrained plant personnel responding to the fire had exposure to pyrolysis by-products, particulates, and extinguisher ingredients. Ten workers taken for medical evaluation had respiratory and nonspecific systemic symptoms consistent with exposure to phosphine gas. Six of the 10 workers had respiratory distress, indicated by chest pain, shortness of breath, elevated respiratory rate, or decreased oxygen saturation. Recommendations are made for the management of similar illnesses and prevention of similar exposures. PMID:23540306

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

2013-01-01

181

(Methanol-?O)(perchlorato-?O)bis-(triphenyl-phosphine-?P)silver(I)  

PubMed Central

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

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

2010-01-01

182

Substituted tertiary phosphine Ru(II) organometallics: catalytic utility on the hydrolysis of etofibrate in pharmaceuticals.  

PubMed

Some new organometallics of ruthenium(II) of the type [RuCl2(COD)(CO)L] (1a-f) and [RuCl2(COD)L2] (2a-f) (where L is substituted tertiary phosphines), have been synthesized by using precursors [RuCl2(COD)(CO)(CH3CN)] (1) and [RuCl2(COD)(CH3CN)2] (2) with the substituted tertiary phosphine ligands in 1:1 and 1:2 molar ratio. The organometallics (2a-f) have been further reacted with carbonmonoxide to produce compounds of the type [RuCl2(CO)L2] (3a-f). These compounds were characterized by elemental analysis, IR, NMR (1H, 13C and 31P), mass and electronic spectral data. The catalytic activity of all these organometallics were studied and found that they are efficient catalysts for hydrolysis of etofibrate. The hydrolyzed product was separated by column chromatography and the percent yields are found in the range of 98.6-99.1%. PMID:18160337

Reddy, P Muralidhar; Shanker, Kanne; Rohini, Rondla; Sarangapani, M; Ravinder, Vadde

2007-11-17

183

Substituted tertiary phosphine Ru(II) organometallics: Catalytic utility on the hydrolysis of etofibrate in pharmaceuticals  

NASA Astrophysics Data System (ADS)

Some new organometallics of ruthenium(II) of the type [RuCl 2(COD)(CO)L] ( 1a-f) and [RuCl 2(COD)L 2] ( 2a-f) (where L is substituted tertiary phosphines), have been synthesized by using precursors [RuCl 2(COD)(CO)(CH 3CN)] ( 1) and [RuCl 2(COD)(CH 3CN) 2] ( 2) with the substituted tertiary phosphine ligands in 1:1 and 1:2 molar ratio. The organometallics ( 2a-f) have been further reacted with carbonmonoxide to produce compounds of the type [RuCl 2(CO)L 2] ( 3a-f). These compounds were characterized by elemental analysis, IR, NMR ( 1H, 13C and 31P), mass and electronic spectral data. The catalytic activity of all these organometallics were studied and found that they are efficient catalysts for hydrolysis of etofibrate. The hydrolyzed product was separated by column chromatography and the percent yields are found in the range of 98.6-99.1%.

Reddy, P. Muralidhar; Shanker, Kanne; Rohini, Rondla; Sarangapani, M.; Ravinder, Vadde

2008-10-01

184

Development of potent and selective phosphinic peptide inhibitors of angiotensin-converting enzyme 2.  

PubMed

Angiotensin-converting enzyme 2 (ACE2), a recently identified human homologue of angiotensin-converting enzyme, is a zinc metallocarboxypeptidase which may play a unique role in cardiovascular and renal function. Here we report the discovery of potent and selective inhibitors of ACE2, which have been identified by evaluating a series of phosphinic di- and tripeptides of the general formula: Z-Xaa(PO 2-CH 2)YaaOH and Ac-Zaa-Xaa(PO 2-CH 2)YaaOH. The most potent inhibitor in this series is a tripeptide that displays a K i value of 0.4 nM toward ACE2 and is 3 orders of magnitude less potent toward carboxypeptidase A. Phosphinic tripeptides exhibit high potency exclusively when the Xaa position is occupied by a pseudoproline. A model of interaction between one inhibitor of this series and ACE2 suggests that the critical role played by a proline in inhibitors, but also for substrates hydrolysis, may rely on the presence of Tyr (510) in the ACE2 active site. PMID:18324760

Mores, Andreas; Matziari, Magdalini; Beau, Fabrice; Cuniasse, Philippe; Yiotakis, Athanasios; Dive, Vincent

2008-03-07

185

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

SciTech Connect

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.

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

2011-03-31

186

Study of Molecular Structures and Properties of Europium(III) Complexes with Phosphine Oxides by NMR Analysis  

NASA Astrophysics Data System (ADS)

The 31P-NMR spectra of europium complexes with ?-diketones and phosphine oxides in CDCl3, DMSO-d6, toluene-d8 with dissolved fluorinated polymers, and fluorinated solvent were investigated as well as the temperature dependence of these spectra. When a mixture of europium complex 1 and 1.0 molar equivalent of trioctylphosphine oxide and triphenylphosphine oxide was dissolved in a fluorinated solvent, europium complex 2 with two types of phosphine oxides was formed at room temperature. In CDCl3 and toluene-d8 solutions, however, this complex was identified only at low temperatures. This difference is thought to be due to the differences in the speed of ligand exchanges. In DMSO-d6 solution, no signal corresponding to the europium complex with phosphine oxides was observed. This implies that the major portion of phosphine oxides is not coordinated with europium ions in DMSO-d6 solution. The fluorescence intensity of each europium complex in a solvent was correlated to the solvent and the 31P-NMR spectrum. It was found that the fluorescence intensity was the highest in the fluorinated solvent.

Iwanaga, Hiroki; Amano, Akio; Oguchi, Masayuki

2005-06-01

187

Reactions of phosphine oxides with bromophosphoranimines; synthesis and unusual rearrangements of O-donor stabilized phosphoranimine cations.  

PubMed

Reaction of phosphine oxides R(3)P?O [R = Me (1a), Et (1c), (i)Pr (1d) and Ph (1e)], with the bromophosphoranimines BrPR'R''P?NSiMe(3) [R' = R'' = Me (2a); R' = Me, R'' = Ph (2b); R' = R'' = OCH(2)CF(3) (2c)] in the presence or absence of AgOTf (OTf = CF(3)SO(3)) resulted in a rearrangement reaction to give the salts [R(3)P?N?PR'R''O-SiMe(3)]X (X = Br or OTf) ([4]X). Reaction of phosphine oxide 1a with the phosphoranimine BrPMe(2)?NSiPh(3) (5) with a sterically encumbered silyl group also resulted in the analogous rearranged product [Me(3)P?N?PMe(2)O-SiPh(3)]X ([8]X) but at a significantly slower rate. In contrast, the direct reaction of the bulky tert-butyl substituted phosphine oxide, (t)Bu(3)P?O (1b) with 2a or 2c in the presence of AgOTf yielded the phosphine oxide-stabilized phosphoranimine cations [(t)Bu(3)P?O·PR'(2)?NSiMe(3)](+) ([3](+), R' = Me (d), OCH(2)CF(3) (e)). A mechanism is proposed for the unexpected formation of [4](+) in which the formation of the donor-stabilized adduct [3](+) occurs as the first step. PMID:21928766

Bendle, Martin; Huynh, Keith; Haddow, Mairi F; Manners, Ian

2011-09-19

188

Phosphine-catalyzed Rauhut-Currier domino reaction: a facile strategy for the construction of carbocyclic spirooxindoles skeletons.  

PubMed

Push-over: A novel domino reaction of activated conjugated dienes and methyleneindolinones incorporates a phosphine-catalyzed intermolecular Rauhut-Currier to form two C-C bonds and a quaternary carbon center. This method can be used to synthesize spirocyclopenteneoxindoles skeletons, which are potential building blocks for biologically active compounds. PMID:23813882

Hu, Chongchong; Zhang, Qinglong; Huang, You

2013-06-28

189

Phosphine Resistance in the Rust Red Flour Beetle, Tribolium castaneum (Coleoptera: Tenebrionidae): Inheritance, Gene Interactions and Fitness Costs  

PubMed Central

The recent emergence of heritable high level resistance to phosphine in stored grain pests is a serious concern among major grain growing countries around the world. Here we describe the genetics of phosphine resistance in the rust red flour beetle Tribolium castaneum (Herbst), a pest of stored grain as well as a genetic model organism. We investigated three field collected strains of T. castaneum viz., susceptible (QTC4), weakly resistant (QTC1012) and strongly resistant (QTC931) to phosphine. The dose-mortality responses of their test- and inter-cross progeny revealed that most resistance was conferred by a single major resistance gene in the weakly (3.2×) resistant strain. This gene was also found in the strongly resistant (431×) strain, together with a second major resistance gene and additional minor factors. The second major gene by itself confers only 12–20× resistance, suggesting that a strong synergistic epistatic interaction between the genes is responsible for the high level of resistance (431×) observed in the strongly resistant strain. Phosphine resistance is not sex linked and is inherited as an incompletely recessive, autosomal trait. The analysis of the phenotypic fitness response of a population derived from a single pair inter-strain cross between the susceptible and strongly resistant strains indicated the changes in the level of response in the strong resistance phenotype; however this effect was not consistent and apparently masked by the genetic background of the weakly resistant strain. The results from this work will inform phosphine resistance management strategies and provide a basis for the identification of the resistance genes.

Jagadeesan, Rajeswaran; Collins, Patrick J.; Daglish, Gregory J.; Ebert, Paul R.; Schlipalius, David I.

2012-01-01

190

Supramolecular bulky phosphines comprising 1,3,5-triaza-7-phosphaadamantane and Zn(salphen)s: structural features and application in hydrosilylation catalysis.  

PubMed

The use of the commercially available, bifunctional phosphine 1,3,5-triaza-7-phosphaadamantane (abbreviated as PN3) in conjunction with a series of Zn(salphen) complexes leads to sterically encumbered phosphine ligands as a result of (reversible) coordinative Zn-N interactions. The solid state and solution phase behaviour of these supramolecular ligand systems have been investigated in detail and revealed their stoichiometries in the solid state observed by X-ray crystallography, and those determined in solution by NMR and UV-Vis spectroscopy. Also, upon application of these supramolecular bulky phosphines in hydrosilylation catalysis employing 1-hexene as a substrate, the catalysis data infer the presence of an active Rh species with two coordinated, bulky PN3/Zn(salphen) assembly units having a maximum of three Zn(salphen)s associated per PN3 scaffold, with an excess of bulky phosphines hardly affecting the overall activity. PMID:23535854

Anselmo, Daniele; Gramage-Doria, Rafael; Besset, Tatiana; Escárcega-Bobadilla, Martha V; Salassa, Giovanni; Escudero-Adán, Eduardo C; Martínez Belmonte, Marta; Martin, Eddy; Reek, Joost N H; Kleij, Arjan W

2013-06-01

191

Palladium-catalyzed reactions of hypophosphorous compounds with allenes, dienes, and allylic electrophiles: methodology for the synthesis of allylic h-phosphinates.  

PubMed

Hypophosphorous compounds (MOP(O)H(2), M = H, R(3)NH) effectively participate in metal-catalyzed C-P bond-forming reactions with allenes, dienes, and activated allylic electrophiles under mild conditions. The catalytic system Pd(2)dba(3)/xantphos is crucial to avoid or minimize the competitive reductive transfer-hydrogenation pathway available to hypophosphorous acid derivatives. Further investigation into the allylation mechanism provided access to the analogy allylic acetate-allylic phosphinate, which then led to the development of a Pd-catalyzed rearrangement of preformed allylic phosphinates esters and, ultimately, to a catalytic dehydrative allylation of hypophosphorous acid with allylic alcohols. The reactions disclosed herein constitute efficient synthetic approaches, not only to prepare allylic H-phosphinic acids but also their esters via one-pot tandem processes. In addition, the potential of H-phosphinates as useful synthons for the preparation of other organophosphorus compounds is demonstrated. PMID:18275217

Bravo-Altamirano, Karla; Abrunhosa-Thomas, Isabelle; Montchamp, Jean-Luc

2008-02-15

192

Reactions of elemental phoshorus and phosphine with electrophiles in superbasic systems: XIX. Formation of the CP bond with participation of elemental phosphorus under microwave assistance  

Microsoft Academic Search

Microwave irradiation facilitates phosphorylation of aryl methyl chlorides and styrene with red phosphorus in the presence\\u000a of strong bases and increases the yield of the main products, tertiary phosphine oxides.

S. F. Malysheva; N. K. Gusarova; V. A. Kuimov; B. G. Sukhov; A. A. Kudryavtsev; O. G. Sinyashin; Yu. G. Budnikova; Z. P. Pai; A. G. Tolstikov; B. A. Trofimov

2007-01-01

193

Matrix-bound phosphine in sediments from Lake Illawarra, New South Wales, Australia.  

PubMed

Matrix-bound phosphine (MBP) has been measured in sediment from two cores in Lake Illawarra on the south east coast of Australia. The sediments were also dated in the upper layers. MBP concentrations found range from 142 to 1813 ng kg(-1), dw (dry weight of sediment) with some values being amongst the highest ever measured. Values of MBP in deeper sediments were higher than for near surface samples, but the patterns with depth were not consistent. Strong correlations were noted between MBP and organic phosphorus (OP, r>0.8) and with total phosphorus (TP, r>0.7), but only moderate correlations were found with organic carbon (OC, r>0.5). No correlations were found between MBP concentrations and the age of the sediments. It was confirmed that high MBP concentrations are indicative of a phosphorus rich environment. The results tend to support the premise that MBP is generated by microbial attack on OP under anaerobic conditions. PMID:21683422

Song, Xiuxian; Morrison, R J; Feng, Zhihua; Liu, Dongyan; Harrison, J J; Yu, Zhiming

2011-06-16

194

A cyclic voltammetric study of iron(II)\\/ruthenium(II) complexes with bis (tertiary phosphines)  

Microsoft Academic Search

Nine complexes of FeIIRuII with bis(tertiary phosphines), namely, 1,2-bis(diphenylphosphino)ethane (dppe), 1,2-bis (diphenylphosphino)ethylene (dppen) and o-phenylenebis (diphenylphosphine) (o-diphos) were studied using cyclic voltammetry. The half-wave potentials for the complexes studied are: (1) [FeCl2(dppe)], 0.050V; (2) [Fe(NCS)2(dppe)2], 0.265V; (3) [RuCl2(dppe)2], 0.548V; (4) [FeCl2(dppen)2], 0.225V; (5) [Fe(NCS)2-(dppen)2], 0.290V; (6) [RuCl2(dppen)2], 0.690V; (7) [FeCl2(o-diphos)2] 0.160V; (8) [Fe(NCS)2(o-diphos)2] 0.582V; and (9) [RuCl2(o-diphos)2], 0.265V. The redox

Tarlok S. Lobana; Michael Gratzel; Mohammad K. Nazeeruddin; Nicholas Vlachopolous

1996-01-01

195

Extraction of phenols from water with tri-octyl phosphine oxide  

SciTech Connect

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.

MacGlashan, J.D.

1982-03-01

196

Organic Vapor Sorption in a High Surface Area Dysprosium(III)-Phosphine Oxide Coordination Material.  

PubMed

PCM-16 is a phosphine coordination material comprised of Dy(III) and triphenylphosphine oxide, which displays the highest reported CO(2) BET surface area for a Ln(III) coordination polymer of 1511 m(2) g(-1). PCM-16 also adsorbs 2.7 wt % H(2) and 65.1 wt % O(2) at 77 K and 0.97 bar. The adsorption-desorption behavior of a series of organic vapors has been studied in PCM-16 to probe the nature of certain host-guest interactions in the pores. Aromatic and polar guest species showed high uptakes and marked adsorption/desorption hysteresis, while aliphatic vapors were less easily adsorbed. The surface area of PCM-16 could be increased significantly (to 1814 m(2) g(-1)) via exchange of Me(2)NH(2)(+) cations in the pores with smaller NH(4)(+) groups. PMID:23116537

Ibarra, Ilich A; Yoon, Ji Woong; Chang, Jong-San; Lee, Su Kyoung; Lynch, Vincent M; Humphrey, Simon M

2012-11-01

197

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

PubMed

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

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

2007-06-25

198

Charge transport, carrier balance, and blue electrophosphorescence in diphenyl[4-(triphenylsilyl)phenyl]phosphine oxide devices  

NASA Astrophysics Data System (ADS)

Diphenyl[4-(triphenylsilyl)phenyl]phosphine oxide (EMPA1) displays a wide highest occupied molecular orbital-lowest unoccupied molecular orbital gap (4.1 eV), singlet (4.3 eV) and triplet (3.4 eV), and an electron-dominated charge transport that follows a trap-free space charge limited model with an average electron mobility of 5.7×10-6 cm2 V-1 s-1 and a hole mobility of 1.1×10-6 cm2 V-1 s-1. At high driving voltages (>6 V), ambipolar charge transport is observed, resulting in a balanced charge density in the active layer. Highly efficient blue phosphorescent organic light-emitting diodes were realized, showing a high external quantum efficiency (21%) and a luminance efficiency of 45 cd/A using a bis[2-(4',6'-difluorophenyl)-pyridinato-N,C2']iridium(III) picolinate dopant.

Mamada, Masashi; Ergun, Selin; Pérez-Bolívar, César; Anzenbacher, Pavel

2011-02-01

199

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

PubMed

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

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

200

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

NASA Astrophysics Data System (ADS)

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

Zhuang, Hong

1998-11-01

201

Comparison of Dithiophosphinic and Phosphinic Acid Derivatives for Minor Actinide Extraction  

SciTech Connect

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

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

2008-03-01

202

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

SciTech Connect

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

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

2008-03-01

203

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

PubMed

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

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

2013-08-30

204

[2,6-Bis(diphenyl-phosphino-oxy)phen-yl]bis-(trimethyl-phosphine)cobalt(I)  

PubMed Central

The title compound, [Co(C30H23O2P2)(C3H9P)2], was synthesized by the addition of a Co(PMe3)4 solution to (PPh2O)2C6H4. The CoI atom displays a trigonal-bipyramidal geometry with the two P atoms of the ‘PCP’ pincer ligand and the P atom of one of the trimethyl phosphine ligands forming the basal plane, whereas the metalated C atom and the P atom of the second phospine ligand occupy the apical sites. The Co—C distance is 1.961?(2)?Å and the C—Co—P angle is 171.96?(6)°.

Lian, Zhe; Xu, Guoqiang; Li, Xiaoyan

2010-01-01

205

Dimerization of propylene by bis(?-ketiminate) nickel(II) and cobalt(II) catalysts in the presence of organoaluminum activator and phosphine ligand  

Microsoft Academic Search

A preliminary study of the catalytic behavior of bis(?-ketiminate) nickel(II) and cobalt(II) complexes in the dimerization of propylene was undertaken in combination with organoaluminum co-catalyst and ancillary phosphine ligand. The effects of type and relative amounts of aluminum co-catalyst as well as the nature of nickel and cobalt precatalysts were investigated. The results showed that the presence of ancillary phosphine

Sizhong Wu; Shiwei Lu

2003-01-01

206

A convenient method for the preparation of ?-vinylfurans by phosphine-initiated reactions of various substituted enynes bearing a carbonyl group with aldehydes  

Microsoft Academic Search

?-Vinylfurans were obtained by phosphine-initiated cyclization of various enynes bearing a carbonyl group at the ene end in the presence of various aldehydes, in moderate to high yields. The reaction may consist of 1,6-addition of phosphine to the enynes, ring closure, and Wittig reaction between the ylid resulting from cyclization and an aldehyde. Thus, various aldehydes were able to be

Hirofumi Kuroda; Emi Hanaki; Hironori Izawa; Michiko Kano; Hiromi Itahashi

2004-01-01

207

Highly Chemoselective Rauhut-Currier Reaction between Maleimides and Enones and Dual Phosphine-Mediated One-Pot Synthesis of Bicyclic and Polycyclic Skeletons.  

PubMed

A highly chemoselective phosphine-catalyzed Rauhut-Currier reaction between maleimides and enones has been realized under very mild conditions, affording the corresponding cross-coupling products in moderate to excellent yields. On the basis of this reaction, an efficient dual phosphine-mediated one-pot synthesis of bicyclic and polycyclic compounds containing a cyclopenta[c]pyrrole skeleton has been accordingly developed, which features a tandem sequence of intermolecular Rauhut-Currier reaction and intramolecular Wittig reaction. PMID:24087883

Zhou, Rong; Wang, Jianfang; Yu, Jia; He, Zhengjie

2013-10-14

208

Synthesis and Characterization of New Aromatic Poly(amide-imide)s Derived from Bis(3-trimellitimidophenyl) Phenyl Phosphine Oxide and Various Aromatic Diamines  

Microsoft Academic Search

diimide-diacid (I) and aromatic diamines using triphenyl phosphite in N-methyl-2-pyrrolidone (NMP)\\/pyridine solution containing dissolved CaCl2. The bis(3-trimellitimidophenyl) phenyl phosphine oxide (I) was readily obtained by the condensation reaction of bis(3-aminophenyl) phenyl phosphine oxide (BAPPO) with trimellitic anhydride. The resulting poly(amide-imide)s showed high thermostability. Their decomposition temperatures at 10% weight loss in nitrogen atmosphere were above 532 ºC and the anaerobic

A. Banihashemi; B. Tamami; A. Abdolmaleki

209

Synthesis and activity of ruthenium alkylidene complexes coordinated with phosphine and N-heterocyclic carbene ligands.  

PubMed

This paper reports the synthesis and characterization of a variety of ruthenium complexes coordinated with phosphine and N-heterocyclic carbene (NHC) ligands. These complexes include several alkylidene derivatives of the general formula (NHC)(PR(3))(Cl)(2)Ru=CHR', which are highly active olefin metathesis catalysts. Although these catalysts can be prepared adequately by the reaction of bis(phosphine) ruthenium alkylidene precursors with free NHCs, we have developed an alternative route that employs NHC-alcohol or -chloroform adducts as "protected" forms of the NHC ligands. This route is advantageous because NHC adducts are easier to handle than their free carbene counterparts. We also demonstrate that sterically bulky bis(NHC) complexes can be made by reaction of the pyridine-coordinated precursor (NHC)(py)(2)(Cl)(2)Ru=CHPh with free NHCs or NHC adducts. Two crystal structures are presented, one of the mixed bis(NHC) derivative (H(2)IMes)(IMes)(Cl)(2)Ru=CHPh, and the other of (PCy(3))(Cl)(CO)Ru[eta(2)-(CH(2)-C(6)H(2)Me(2))(N(2)C(3)H(4))(C(6)H(2)Me(3))], the product of ortho methyl C-H bond activation. Other side reactions encountered during the synthesis of new ruthenium alkylidene complexes include the formation of hydrido-carbonyl-chloride derivatives in the presence of primary alcohols and the deprotonation of ruthenium vinylcarbene ligands by KOBu(t). We also evaluate the olefin metathesis activity of NHC-coordinated complexes in representative RCM and ROMP reactions. PMID:12603143

Trnka, Tina M; Morgan, John P; Sanford, Melanie S; Wilhelm, Thomas E; Scholl, Matthias; Choi, Tae-Lim; Ding, Sheng; Day, Michael W; Grubbs, Robert H

2003-03-01

210

Chloro- and phenoxy-phosphines in frustrated Lewis pair additions to alkynes.  

PubMed

The reaction of tBu(C(6)H(4)O(2))P, with the borane B(C(6)F(5))(3) gives rise to NMR data consistent with the formation of the classical Lewis acid-base adduct tBu(C(6)H(4)O(2))P(B(C(6)F(5))(3)) (1). In contrast, the NMR data for the corresponding reactions of tBu(C(20)H(12)O(2))P and Cl(C(20)H(12)O(2))P with B(C(6)F(5))(3) were consistent with the presence of equilibria between free phosphine and borane and the corresponding adducts. Nonetheless, in each case, the adducts tBu(C(20)H(12)O(2))P(B(C(6)F(5))(3)) (2) and Cl(C(20)H(12)O(2))P(B(C(6)F(5))(3)) (3) were isolable. The species 1 reacts with PhCCH to give the new species tBu(C(6)H(4)O(2))P(Ph)C=CHB(C(6)F(5))(3) (4) in near quantitative yield. In an analogous fashion, the addition of PhCCH to solutions of the phosphines tBu(C(20)H(12)O(2))P, tBuPCl(2) and (C(6)H(3)(2,4-tBu(2))O)(3)P each with an equivalent of B(C(6)F(5))(3) gave rise to L(Ph)C=CHB(C(6)F(5))(3) (L = tBu(C(20)H(12)O(2))P 5, tBuPCl(2)6 and (C(6)H(3)(2,4-tBu(2))O)(3)P 7). X-Ray data for 1, 2, 6 and 7 are presented. The implications of these findings are considered. PMID:21904729

Caputo, Christopher B; Geier, Stephen J; Ouyang, Eva Y; Kreitner, Christoph; Stephan, Douglas W

2011-09-08

211

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

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

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

2005-01-01

212

Determination of impurities in flame retardant monomer 2-carboxyl ethyl(phenyl) phosphinic acid by ion chromotography.  

PubMed

In this paper, a method based on ion chromatography (IC) with conductivity detector was developed for the determination of impurities including phenyl phosphinic acid (BPA), phenyl phosphonic acid (PPOA) and crylic acid in flame retardant monomer 2-carboxyl ethyl(phenyl) phosphinic acid (CEPPA). Under favorable chromatographic conditions, good linear relationship, sensitivity and reproducibility were obtained. Detection limits of BPA, PPOA and crylic acid were 1.5, 0.5, 0.4 microg l(-1), respectively. Relative standard deviations (RSD) of repeated analyses were less than 2.22% (n=10). The real samples (white crystal) have been tested and rate of recovery were 89-108%. It was confirmed that this method could be used in the analysis of flame retardant monomers. PMID:17349648

Chen, Mei-Lan; Yan, Wei; Chen, Yongxin; Jia, Zhishen; Zhu, Yan

2007-02-20

213

Investigation of the surface chemistry of phosphine-stabilized ruthenium nanoparticles - an advanced solid-state NMR study.  

PubMed

(31)P-(13)C REDOR NMR measurements allowed a reasonable approximation of distances between stabilizing ligands and carbon monoxide (CO) molecules on the surface of phosphine-stabilized ruthenium nanoparticles (RuNPs). The studied systems are RuNPs in the size range of 1-2 nm stabilized with 1,3,5-triaza-7-phosphaadamantane (PTA) or triphenylphosphine (PPh3) and exposed to a CO atmosphere. This study sheds some light on the interactions between CO and phosphine molecules as well as on their binding geometries on the surface of the RuNPs. As information on the ligand location and mobility is precious for the understanding of the chemical and catalytic properties of nanoparticles, these results support the interest of using sophisticated NMR tools to investigate their surface chemistry. PMID:24022656

Gutmann, Torsten; Bonnefille, Eric; Breitzke, Hergen; Debouttière, Pierre-Jean; Philippot, Karine; Poteau, Romuald; Buntkowsky, Gerd; Chaudret, Bruno

2013-09-25

214

Synthesis and Microwave Spectrum of (2-Chloroethyl)phosphine (ClCH2CH2PH2)  

NASA Astrophysics Data System (ADS)

The synthesis of a 2-halogenoethylphosphine, (2-chloroethyl)phosphine (ClCH2CH2PH2), is reported for the first time. This compound was prepared by a chemoselective reduction of diethylchloroethylphosphonate with dichloroalane using a vacuum line. (2-Chloroethyl)phosphine has been studied by microwave spectroscopy at room temperature, or at -20 °C, in the 22-80 GHz spectral interval. The experimental study has been augmented by quantum chemical calculations at the MP2/6-311++(3df,3pd) and B3LYP/6-311++(3df,3pd) levels of theory. The spectra of two rotameric forms, denoted I and II have been assigned. These conformers both have an antiperiplanar arrangement for the Cl-C-C-P chain of atoms, but with different orientation of the phosphine group. Conformer I was found to be 5.2(6) kJ/mol more stable than II by relative intensity measurements. The spectra of the first excited states of the C-C torsional vibration of both I and II were assigned. The torsional frequency was determined to be 63(20) cm-1 for conformer I by relative intensity measurements, and it has a similar value in II. It was found that this normal vibration deviates from a near-harmonic behavior. The quantum chemical calculations produce rotational and centrifugal distortion constants that are in satisfactory agreement with observations, but fail to predict correctly low-frequency fundamental frequencies. The quantum chemical calculations indicate that three additional conformers characterized by a synclinal orientation for the Cl-C-C-P link of atoms and with different orientation of the phosphine group are high-energy forms of ClCH2CH2PH2. Searches for these forms were unsuccessful.

Møllendal, Harald; Konovalov, Alexey; Guillemin, Jean-Claude

2009-10-01

215

Synthesis and catalytic chemistry of two new water-soluble chelating phosphines. Comparison of ionic and nonionic functionalities  

Microsoft Academic Search

Two new water-soluble chelating alkyl phosphines are described. The compounds are prepared by radical addition of allylic substrates to 1,2-bis(phosphino)ethane in methanol. Complexes with the stoichiometry of 1.5:1 diphosphine:rhodium(I) are effective in the hydrogenation of the olefins 1-hexene and crotonaldehyde. Catalyst solutions prepared with the ligand DSPrPE were found to be 3 times more active than those prepared with TPPTS

Gregory T. Baxley; T. J. R. Weakley; Warren K. Miller; David K. Lyon; David R. Tyler

1997-01-01

216

Carbonylation of aryl halides catalyzed by a silica-supported sulfur and phosphine mixed bidentate palladium complex  

Microsoft Academic Search

A silica-supported sulfur and phosphine mixed bidentate palladium complex has been prepared from 4-thia-6-chlorohexyltrimethoxysilane via immobilization on fumed silica, followed by reacting with potassium diphenylphosphide in tetrahydrofuran (THF) and then the reaction with palladium chloride in acetone. This polymeric palladium complex is an efficient catalyst for Heck carbonylation of aryl halides with aniline or n-butyl alcohol under atmospheric pressure of

Mingzhong Cai; Hong Zhao; Yixiang Huang

2005-01-01

217

Environmentally benign synthesis of h-phosphinic acids using a water-tolerant, recyclable polymer-supported catalyst.  

PubMed

[reaction: see text] A reusable polymer-supported hydrophosphinylation catalyst is described for the preparation of H-phosphinic acids. The polystyrene-based ligand is prepared in one step from commercially available compounds. The polymeric catalyst generally gives good yields for a variety of substrates and is water- and air-tolerant, although the scope of alkenes and alkynes which can be employed is somewhat narrower than with our original xantphos/Pd(2)dba(3) catalyst. PMID:15469354

Deprèle, Sylvine; Montchamp, Jean-Luc

2004-10-14

218

Phosphine-free synthesis of metal chalcogenide quantum dots by means of in situ-generated hydrogen chalcogenides  

Microsoft Academic Search

We proved that various organic solvents react with elemental chalcogens (sulfur and selenium) by liberating hydrogen chalcogenide\\u000a (H2X, X = S, Se) during the phosphine-free hot-matrix synthesis of quantum dots. The in situ-produced H2X reacts further with the metal salt to form the corresponding nanosized metal chalcogenide CdX. The effect of temperature\\u000a on the rate of H2X generation was quantitatively

Georgi G. Yordanov; Hideyuki Yoshimura; Ceco D. Dushkin

2008-01-01

219

Microwave-mediated reduction of disulfide bridges with supported (tris(2-carboxyethyl)phosphine) as resin-bound reducing agent.  

PubMed

We report on the synthesis and use of a new supported reagent consisting in tris(2-carboxyethyl)phosphine (TCEP) immobilized on hydrophilic PEG based resin beads. Used in conjunction with a 5 min microwave (MW) irradiation, "supported TCEP" reduced disulfide bridges in free thiols in peptides having two or more cysteine residues. Separation of reaction products from reducing agent was easily performed by simple filtration. PMID:23438263

Miralles, Guillaume; Verdié, Pascal; Puget, Karine; Maurras, Amélie; Martinez, Jean; Subra, Gilles

2013-03-08

220

Formation of donor-acceptor complexes of bis(acetylacetonato)-nickel(II) with phosphine and phosphite ligands in acetonitrile  

Microsoft Academic Search

1.Electrochemical methods, spectrophotometry, and conductometry were used for the first time to demonstrate the capacity of nickel to coordinate trivalent phosphorus ligands (phosphines and phosphites) in acetonitrile as bis(acetylacetonato)nickel(Il).2.Stepwise complexation of s-donor-acceptor molecular and cationic complexes [NiL4]2+ occurs with a shift in the “coordination-dissociation” equilibrium of the excess concentration of the organophosphorus ligand in solution.

A. A. Pozdeeva; N. R. Popod'ko; G. A. Tolstikov; U. M. Dzhemilev; V. S. Kolosnitsyn; S. I. Zhdanov

1986-01-01

221

Reactions of p-Nitrophenyl Diphenyl Phosphinate with Fluoride and Hydroxide Ion in Nonionic Micelles: Kinetic Salt Effects  

Microsoft Academic Search

Reactions of p-nitrophenyl diphenyl phosphinate (p-NPDP) with OH? and F? are inhibited by micelles of dodecyl polyoxyethylene ethers C12E10 and C12E23. Rate constants decrease sharply in very dilute surfactant and become approximately constant as p-NPDP becomes fully micellar bound, with inhibition by approximately an order of magnitude. The first-formed fluoridate is detected by NMR spectroscopy in reaction with F? in

Clifford A. Bunton; Houshang J. Foroudian; Nicholas D. Gillitt; Christy R. Whiddon

1999-01-01

222

Phosphine-catalyzed synthesis of 3,3-spirocyclopenteneoxindoles from ?-substituted allenoates: systematic studies and targeted applications.  

PubMed

The phosphine-promoted [3 + 2] cyclizations between ?-substituted allenoates and arylideneoxindoles have been applied to the stereoselective synthesis of spiro(cyclopentene)oxindoles with trisubstituted cyclopentene units. It has been demonstrated that PPh(3) operates a very efficient control of the relative stereochemistry of the three stereogenic centers of the final spiranic products. Focused experiments have been carried out then so as to access carbocyclic analogues of an important series of anticancer agents inhibiting MDM2-p53 interactions. PMID:23343506

Gomez, Catherine; Gicquel, Maxime; Carry, Jean-Christophe; Schio, Laurent; Retailleau, Pascal; Voituriez, Arnaud; Marinetti, Angela

2013-02-06

223

Phosphine-catalyzed [3 + 2] cycloaddition of sulfamate-derived cyclic imines with allenoate: synthesis of sulfamate-fused dihydropyrroles.  

PubMed

Ph3P-catalyzed [3 + 2] cycloaddition reaction of sulfamate-derived cyclic imines with allenoate has been developed, affording sulfamate-fused dihydropyrroles under very mild conditions in high yields. Using amino acid-based bifunctional phosphine as chiral catalyst, its asymmetric variant provided the corresponding products in good yields with moderate to excellent enantiomeric excesses (up to 91% yield and up to 98% ee). Subsequent transformations of the heterocyclic products gave various pharmaceutically attractive compounds. PMID:23895382

Yu, Hao; Zhang, Lei; Yang, Zhilin; Li, Zhen; Zhao, Yan; Xiao, Yumei; Guo, Hongchao

2013-08-14

224

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

Microsoft Academic Search

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

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

2004-01-01

225

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

PubMed Central

Palladium-catalyzed amidation of five-membered heterocyclic bromides that contain multiple heteroatoms was achieved for the first time using the Pd/1 catalyst system. This system allows for efficient access to N-arylated imidazoles, pyrazoles, thiazoles, pyrroles, and thiophenes in moderate to excellent yield. Experimental results and DFT calculations point to the need for electron-rich and especially sterically demanding biaryl phosphine ligand to promote these difficult cross-coupling reactions.

Su, Mingjuan; Buchwald, Stephen L.

2012-01-01

226

Recovery of plutonium from nitric acid containing oxalate and fluoride by a macroporous bifunctional phosphinic acid resin (MPBPA)  

Microsoft Academic Search

Summary  The sorption of Pu from nitric acid solutions containing oxalate\\/fluoride was studied using an indigenously available macroporous\\u000a bifunctional phosphinic acid (MPBPA) resin. Batch experiments were carried out to obtain the distribution data of Pu(IV) with\\u000a a view to optimize conditions for its recovery from nitric acid waste solutions containing oxalate or fluoride ions. The measurements\\u000a showed high distribution ratio (D)

K. Venugopal Chetty; A. G. Godbole; R. Swarup; V. N. Vaidya; V. Venugopal; P. R. Vasudeva Rao

2005-01-01

227

Back-extraction Of Pu From 20% Tributyl Phosphate – 20% Mixed Trialkyl Phosphine Oxides\\/kerosene In The Presence Of  

Microsoft Academic Search

Back-extraction of Pu from a mixture of 20% tributyl phosphate (TBP) and 20% mixed trialkyl phosphine oxides (TRPO) in kerosene in the presence of UO 2was studied. The back-extractants investigated may be divided into three groups: carboxylic acids and salts, amino polycarboxylates, and phosphonic acid. The distribution coefficients of both Pu and UO 2using a number of different back-extractants were

Binbing Han; Qiulin Wu; Yongjun Zhu; S. R. Wickramasinghe

2005-01-01

228

Efficient asymmetric synthesis of P-chiral phosphine oxides via properly designed and activated benzoxazaphosphinine-2-oxide agents.  

PubMed

A general, efficient, and highly diastereoselective method for the synthesis of structurally and sterically diverse P-chiral phosphine oxides was developed. The method relies on sequential nucleophilic substitution on the versatile chiral phosphinyl transfer agent 1,3,2-benzoxazaphosphinine-2-oxide, which features enhanced and differentiated P-N and P-O bond reactivity toward nucleophiles. The reactivities of both bonds are fine-tuned to allow cleavage to occur even with sterically hindered nucleophiles under mild conditions. PMID:23369026

Han, Zhengxu S; Goyal, Navneet; Herbage, Melissa A; Sieber, Joshua D; Qu, Bo; Xu, Yibo; Li, Zhibin; Reeves, Jonathan T; Desrosiers, Jean-Nicolas; Ma, Shengli; Grinberg, Nelu; Lee, Heewon; Mangunuru, Hari P R; Zhang, Yongda; Krishnamurthy, Dhileep; Lu, Bruce Z; Song, Jinhua J; Wang, Guijun; Senanayake, Chris H

2013-02-06

229

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

PubMed

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

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

2012-03-26

230

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

PubMed Central

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.

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

2012-01-01

231

Photocatalytic hydrogen generation from water with iron carbonyl phosphine complexes: improved water reduction catalysts and mechanistic insights.  

PubMed

An extended study of a novel visible-light-driven water reduction system containing an iridium photosensitizer, an in situ iron(0) phosphine water reduction catalyst (WRC), and triethylamine as sacrificial reductant is described. The influences of solvent composition, ligand, ligand-to-metal ratio, and pH were studied. The use of monodentate phosphine ligands led to improved activity of the WRC. By applying a WRC generated in situ from Fe(3) (CO)(12) and tris[3,5-bis(trifluoromethyl)phenyl]phosphine (P[C(6)H(3)(CF(3))(2)](3), Fe(3)(CO)(12)/PR(3)=1:1.5), a catalyst turnover number of more than 1500 was obtained, which constitutes the highest activity reported for any Fe WRC. The maximum incident photon to hydrogen efficiency obtained was 13.4% (440 nm). It is demonstrated that the evolved H(2) flow (0.23 mmol H(2) h(-1) mg(-1) Fe(3)(CO)(12)) is sufficient to be used in polymer electrolyte membrane fuel cells, which generate electricity directly from water with visible light. Mechanistic studies by NMR spectroscopy, in situ IR spectroscopy, and DFT calculations allow for an improved understanding of the mechanism. With respect to the Fe WRC, the complex [HNEt(3)](+)[HFe(3)(CO)(11)](-) was identified as the key intermediate during the catalytic cycle, which led to light-driven hydrogen generation from water. PMID:21506181

Gärtner, Felix; Boddien, Albert; Barsch, Enrico; Fumino, Koichi; Losse, Sebastian; Junge, Henrik; Hollmann, Dirk; Brückner, Angelika; Ludwig, Ralf; Beller, Matthias

2011-04-19

232

Mechanism of the sulfurisation of phosphines and phosphites using 3-amino-1,2,4-dithiazole-5-thione (xanthane hydride).  

PubMed

Contrary to a previous report, the sulfurisation of phosphorus(III) derivatives by 3-amino-1,2,4-dithiazole-5-thione (xanthane hydride) does not yield carbon disulfide and cyanamide as the additional reaction products. The reaction of xanthane hydride with triphenyl phosphine or trimethyl phosphite yields triphenyl phosphine sulfide or trimethyl thiophosphate, respectively, and thiocarbamoyl isothiocyanate which has been trapped with nucleophiles. The reaction pathway involves initial nucleophilic attack of the phosphorus at sulfur next to the thiocarbonyl group of xanthane hydride followed by decomposition of the phosphonium intermediate formed to products. The Hammett rho-values for the sulfurisation of substituted triphenyl phosphines and triphenyl phosphites in acetonitrile are approximately -1.0. The entropies of activation are very negative (-114+/-15 J mol-1 K-1) with little dependence on solvent which is consistent with a bimolecular association step leading to the transition state. The negative values of DeltaS(not equal) and rho values indicate that the rate limiting step of the sulfurisation reaction is formation of the phosphonium ion intermediate which has an early transition state with little covalent bond formation. The site of nucleophilic attack has been also confirmed using computational calculations. PMID:17252130

Hanusek, Jirí; Russell, Mark A; Laws, Andrew P; Jansa, Petr; Atherton, John H; Fettes, Kevin; Page, Michael I

2006-12-18

233

Preferential site displacement of carbon monoxide by phosphine on Rh/Al sub 2 O sub 3 surfaces  

SciTech Connect

Transmission infrared spectroscopy is used to show that specific bonding sites of CO are preferentially displaced upon exposure of a CO-saturated Rh/Al{sub 2}O{sub 3} surface to PH{sub 3}. Carbon monoxide is bound in three primary adsorption states on Al{sub 2}O{sub 3} supported Rh, with bridged, atop, and gem-dicarbonyl bonding. At all adsorption temperatures studied (90-300 K), phosphine exposure readily leads to removal of CO bound in gem-dicarbonyl sites. The other states of CO are perturbed in their bonding with the surface, as evidenced by a red shift to lower frequencies in the CO stretching vibrations. At surface temperatures {ge} 300 K, CO adsorbed in bridged sites are also displaced by phosphine adsorption. Production of Rh(CO)PH{sub 3} is spectroscopically verified upon PH{sub 3} exposure of a Rh/Al{sub 2}O{sub 3} surface containing only the gem-dicarbonyl species. Similarities are found between the observed surface displacement reactions and phosphine substitution in metal carbonyl clusters.

Lu, Guangquan; Darwell, J.E.; Crowell, J.E. (Univ. of California, San Diego, La Jolla (USA))

1990-10-18

234

Photolysis of phosphine in the presence of acetylene and propyne, gas mixtures of planetary interest  

NASA Astrophysics Data System (ADS)

Phosphine (PH_3) 1 has been observed in the atmospheres of Jupiter and Saturn. We have studied the photochemical reactions of this compound with acetylene (C_2H_2), an alkyne also detected in these atmospheres. The volatile products formed in these reactions were characterized by ^1H, ^31P and ^13C NMR. The ethenylphosphine 2 is the first product formed in the photolysis of PH_3 in the presence of C_2H_2. Photolysis of PH_3 in the presence of propyne (C_3H_4) led to the formation of the Z- and E-prop-1-enylphosphines and traces of 1-methylethenylphosphine. A reaction pathway is proposed. The initial step is the dissociation of PH_3 to hydrogen and PH_2 radicals. Addition of the phosphinyl radical on alkyne occurs as the next step. Vinylphosphines are then formed by radical combination. This proposed reaction pathway takes into account the nature of the products and studies devoted to the photolysis of germane (GeH_4) or hydrogen sulfide (H_2S) in the presence of alkyne. Attempts to detect the methylidynephosphine HC=P (the isoelectronic compound of HC=N), in the photolysis products of PH_3-C_2H_2 mixtures were unsuccessful. The application of these findings to Jovian and Saturn atmospheric chemistry is discussed.

Guillemin, J.-C.; Janati, T.; Lassalle, L.

1995-08-01

235

Sky-blue luminescent Au(I)-Ag(I) alkynyl-phosphine clusters.  

PubMed

Treatment of the (AuC2R)n acetylides with phosphine ligand 1,4-bis(diphenylphosphino)butane (PbuP) and Ag(+) ions results in self-assembly of the heterobimetallic clusters of three structural types depending on the nature of the alkynyl group. The hexadecanuclear complex [Au12Ag4(C2R)12(PbuP)6](4+) (1) is formed for R = Ph, and the octanuclear species [Au6Ag2(C2R)6(PbuP)3](2+) adopting two structural arrangements in the solid state were found for the aliphatic alkynes (R = Bu(t) (2), 2-propanolyl (3), 1-cyclohexanolyl (4), diphenylmethanolyl (5), 2-borneolyl (6)). The structures of the compounds 1-4 and 6 were determined by single crystal X-ray diffraction analysis. The NMR spectroscopic studies revealed complicated dynamic behavior of 1-3 in solution. In particular, complexes 2 and 3 undergo reversible transformation, which involves slow interconversion of two isomeric forms. The luminescence behavior of the titled clusters has been studied. All the compounds exhibit efficient sky-blue room-temperature phosphorescence both in solution and in the solid state with maximum quantum yield of 76%. The theoretical DFT calculations of the electronic structures demonstrated the difference in photophysical properties of the compounds depending on their structural topology. PMID:23517461

Koshevoy, Igor O; Karttunen, Antti J; Kritchenkou, Ilya S; Krupenya, Dmitrii V; Selivanov, Stanislav I; Melnikov, Alexei S; Tunik, Sergey P; Haukka, Matti; Pakkanen, Tapani A

2013-03-21

236

Photophysics of Mixed Ligand Complexes of Ruthenium(II) with 2,2'-bipyridyl and Phosphines  

NASA Astrophysics Data System (ADS)

Luminescence of mixed ligand complexes of ruthenium(II) of the types cis-Ru(bpy)2X2( I), cis-[Ru(bpy)2(PPh3)X](BF4)( II), and cis-Ru(bpy)(PP)X2( III) (X = CN, NO2, PPh3 is triphenyl phosphine; PP is 1,2-bis(diphenylphospino)ethane (dppe) and cis-,2-bis(diphenylphosphino)ethylene (dppene)) is studied in alcohol matrices (EtOH/MeOH, 4:1) frozen at 77 K. A sequence of complexes I-III exhibits an additive (in the number of phosphorous atoms) blue shift of the absorption and luminescence bands and an increase in the quantum yield of luminescence and in the excited-state lifetime. The rate constant of nonradiative deactivation of the excited state decreases more than by an order of magnitude in the sequence I-III of cyano complexes and only by three times in a sequence of nitro complexes. This is assumed to be caused by a specific (in the hydrogen bond type) interaction of nitro groups of complexes with a proton solvent.

Litke, S. V.; Mezentseva, T. V.; Litke, A. S.; Lyalin, G. N.; Ershov, A. Yu.

2000-12-01

237

Geminal tetraauration of acetonitrile: hemilabile-phosphine-stabilized Au8Ag4 cluster compounds.  

PubMed

Unprecedented geminal tetraauration of acetonitrile has been realized through C-H activation by Au(I)-Ag(I) clusters under mild conditions. The reaction of [OAu3Ag(dppy)3](BF4)2 (dppy = diphenylphosphino-2-pyridine) (1), AgBF4, and acetonitrile in the presence of methanol at room temperature resulted in the isolation of the novel cluster [(CCN)2Au8Ag4(dppy)8(CH3CN)2](BF4)6 (2). The centrosymmetric structure consists of two Au4Ag2 motifs stabilized by hemilabile phosphines. Triply deprotonated acetonitrile (CCN(3-)) is found in a Au4Ag environment with the terminal carbon bridging four Au(I) centers and the nitrogen donor linking a Ag(I) ion, which is the first example of a ?5-CCN(3-) coordination mode. A concerted metalation/deprotonation process for the C-H activation of acetonitrile that indicates the importance of the oxo ion of the oxonium Au(I) cluster is proposed. Cluster 2 emits bright green light in the solid state at room temperature upon UV irradiation. PMID:23581858

Pei, Xiao-Li; Yang, Yang; Lei, Zhen; Wang, Quan-Ming

2013-04-17

238

DNA dynamics by using highly luminescent phosphine complex of osmium (II)  

NASA Astrophysics Data System (ADS)

A new highly luminescent 'molecular light switch' has been prepared using osmium (II) metal and nonchromophoric phosphine (dppe) and chromophoric (dppz) ligands to study the dynamics of DNA, where dppe is cis-1,2-bis(diphenylphosphino)-ethylene and dppz is dipyrido[3,2-a:2',3'-c]phenazine. The complex, [Os(dppe)2(dppz)]2+, shows a quantum yield in acetonitrile about twofold larger than analogous ruthenium compound, [Ru(bpy)2(dppz)]2+. The anisotropy of [Os(dppe)2(dppz)]2+ was found to be near 0.2 at -60 degrees Celsius in glycerol. This compound emits at 610 nm on exciting at metal to ligand charge transfer (MLCT) band (390 nm). The lifetimes are 550 and 315 ns in argon and air equilibrated acetonitrile samples respectively. This new class of fluorophore using MLCT complex is useable for measurement of DNA dynamics over a larger time scales, which is not possible with conventional DNA dyes, such as ethidium bromide or acridine derivatives.

Murtaza, Zakir; Malak, Henryk M.; Lakowicz, Joseph R.

1999-05-01

239

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

SciTech Connect

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).

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

240

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

PubMed

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

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

2012-06-12

241

Use of perfluorinated phosphines to provide thermomorphic anticancer complexes for heat-based tumor targeting.  

PubMed

A series of compounds of general formula [Ru(eta(6)-arene)(pta)(PR(3))Cl]BF(4) (arene = p-cymene or 4-phenyl-2-butanol; pta = 1,3,5-triaza-7-phosphatricyclo[3.3.1.1]decane, PR(3) = PPh(2)(p-C(6)H(4)C(2)H(4)C(8)F(17)), PPh(p-C(6)H(4)C(2)H(4)C(8)F(17))(2), P(p-C(6)H(4)C(2)H(4)C(6)F(13))(3), PPh(3) or P(p-C(6)H(4)F)(3)) have been prepared and characterized by spectroscopic methods. The structure of [Ru(eta(6)-p-cymene)(pta)Cl(P(p-C(6)H(4)F)(3))]BF(4) has also been established in the solid state by X-ray crystallography. The cytotoxicities of the compounds were determined in the A2780 and A2780 cisplatin-resistant cell lines revealing that the fluorinated phosphines significantly increase antiproliferative activity relative to their bis-chloride precursors. Two of the complexes were found to be thermoresponsive, that is, showing poor water solubility at 37 degrees C and good solubility at 42 degrees C, the temperature of a heated tumor, providing a method of tumor targeting. Incubation at 42 degrees C for 2 h resulted in improved cytotoxicities for two of the complexes. PMID:20131860

Renfrew, Anna K; Scopelliti, Rosario; Dyson, Paul J

2010-03-01

242

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

NASA Astrophysics Data System (ADS)

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.

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

2013-07-01

243

A one-pot synthesis of a branched tertiary phosphine oxide from red phosphorus and 1-( tert-butyl)-4-vinylbenzene in KOH–DMSO: an unusually facile addition of P-centered nucleophiles to a weakly electrophilic double bond  

Microsoft Academic Search

Red phosphorus reacts with 1-(tert-butyl)-4-vinylbenzene in a superbase media (KOH–DMSO, 90–100°C, 3h) to give tris[4-(tert-butyl)phenethyl]phosphine oxide in 77% yield. Microwave activation of the reaction affords the phosphine oxide in 82% yield in 6min.

Boris A. Trofimov; Svetlana F. Malysheva; Nina K. Gusarova; Vladimir A. Kuimov; Nataliya A. Belogorlova; Boris G. Sukhov

2008-01-01

244

Highly atom-economic one-pot formation of three different C-P bonds: general synthesis of acyclic tertiary phosphine sulfides.  

PubMed

The reaction of benzothiadiphosphole 1 with an equimolar mixture of R1MgBr and R2MgBr gave intermediate A', which, after only 4-5 min, was treated with an equimolar amount of R3MgBr, giving the asymmetric phosphine PR1R2R3 in 45% overall yield (75-80% yield when R1 = R2 and 85-90% yield when R1 = R2 = R3) and the byproduct 6 in 90% yield. The treatment of 6 with PCl3 quantitatively regenerates the starting reagent 1. Treatment of the phosphines with elemental sulfur gave the corresponding sulfides. PMID:15932317

Baccolini, Graziano; Boga, Carla; Mazzacurati, Marzia

2005-06-10

245

Atom transfer radical polymerisation of styrene controlled by phosphine-containing coordination compounds of Mo(III)\\/Mo(IV)  

Microsoft Academic Search

A controlled polymerisation of styrene has been achieved under ATRP conditions by using a phosphine-containing MoIII\\/MoIV system. Linearity of the Mn vs conversion plot and low PDI’s are observed in bulk, in a 30% (v\\/v) PhCl solution, and in a chain extension experiment when using MoCl3(PMe3)3\\/BIB. Controlled polymerisation is also observed for a reverse ATRP experiment starting from MoCl4(PMe3)3\\/AIBN. The

François Stoffelbach; Jérôme Claverie; Rinaldo Poli

2002-01-01

246

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

DOEpatents

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

Tom, Glenn M. (New Milford, CT); Brown, Duncan W. (Wilton, CT)

1991-01-08

247

(2,4,6-Trimethyl-phen-yl)boronic acid-triphenyl-phosphine oxide (1/1)  

PubMed Central

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

Rosca, Sorin; Olaru, Marian; Rat, Ciprian I.

2012-01-01

248

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

PubMed

Triphenyl phosphine adducts of dithiocarbamate complexes of platinum(IV) and palladium(II) of the type [Pt(L)2PPh3Cl2] and [Pd(L)2PPh3] [L: morpholine dithiocarbamate (L1), aniline dithiocarbamate (L2) and N-(methyl, cyclohexyl) dithiocarbamate (L3)] were prepared and characterized by elemental analysis, electronic, IR, 1H NMR and 13C NMR spectral studies. Thermal studies of the complexes were carried out. In vitro antitumor activity has been screened towards human adenocarcinoma cell lines and showed significant inhibition even at very low concentration. PMID:15477148

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

2004-11-01

249

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

NASA Astrophysics Data System (ADS)

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

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

2004-11-01

250

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

SciTech Connect

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

Xue, Zhang [University of North Texas; Kandala, Srikanth [University of North Texas; Yang, Li [University of North Texas; Watson, William H. [Texas Christian University; Wang, Xiaoping [ORNL; Hrovat, David A. [University of North Texas

2011-01-01

251

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

PubMed

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

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

2012-08-20

252

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

PubMed

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

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

2013-07-01

253

Microwave spectrum, and conformational composition of (chloromethyl)phosphine (ClCH2PH2).  

PubMed

(Chloromethyl)phosphine, (ClCH(2)PH(2)) has been studied by microwave spectroscopy at -30 °C in the 22-80 GHz spectral interval. The experimental study has been augmented by quantum chemical calculations at the MP2/aug-cc-pVQZ and B3LYP/aug-cc-pVTZ levels of theory. The spectra of the ground as well as of several vibrationally excited states of the (35)ClCH(2)PH(2) and (37)ClCH(2)PH(2) isotopologues of two rotameric forms, denoted I and II, have been assigned. These conformers have different orientations of the phosphino group. I has a symmetry plane, consisting of the Cl-C-P link of atoms, whereas the phosphino group is rotated out of this symmetry plane in II. Conformer I was found to be 4.3(5) kJ/mol more stable than II by relative intensity measurements. The rotational and quartic centrifugal distortion constants calculated using the MP2/aug-cc-pVQZ procedure are in very good agreement with their experimental counterparts. Less good agreement is found in the B3LYP/aug-cc-pVTZ calculations. Both computational procedures predict energy differences between I and II that are close to the experimental energy difference. It is suggested that I is the preferred form of this molecule because it is stabilized by weak intramolecular hydrogen bonding between the chlorine atom and the hydrogen atoms of the phosphino group. Repulsion between the lone electron pair of the phosphorus atom and the chlorine atom also stabilizes I relative to II. PMID:20836524

Møllendal, Harald; Konovalov, Alexey; Guillemin, Jean-Claude

2010-10-01

254

Tetrathiafulvalene-phosphine-based iron and ruthenium carbonyl complexes: electrochemical and EPR studies.  

PubMed

The radical cation of the redox active ligand 3,4-dimethyl-3',4'-bis-(diphenylphosphino)-tetrathiafulvalene (P2) has been chemically and electrochemically generated and studied by EPR spectroscopy. Consistent with DFT calculations, the observed hyperfine structure (septet due to the two methyl groups) indicates a strong delocalization of the unpaired electron on the central S2C=CS2 part of the tetrathiafulvalene (TTF) moiety and zero spin densities on the phosphine groups. In contrast with the ruthenium(0) carbonyl complexes of P2 whose one-electron oxidation directly leads to decomplexation and produces P2*+, one-electron oxidation of [Fe(P2)(CO)3] gives rise to the metal-centered oxidation species [Fe(I)(P2)(CO)3], characterized by a coupling with two 31P nuclei and a rather large g-anisotropy. The stability of this complex is however modest and, after some minutes, the species resulting from the scission of a P-Fe bond is detected. Moreover, in presence of free ligand, [Fe(I)(P2)(CO)3] reacts to give the complex [Fe(I)(P2)2(CO)] containing two TTF fragments. The two-electron oxidation of [Fe(P2)(CO)3] leads to decomplexation and to the P2*+ spectrum. Besides EPR spectroscopy, cyclic voltammetry as well as FTIR spectroelectrochemistry are used in order to explain the behaviour of [Fe(P2)(CO)3] upon oxidation. This behaviour notably differs from that of the Ru(0) counterpart. This difference is tentatively rationalized on the basis of structural arguments. PMID:19785176

Gouverd, Cyril; Biaso, Frédéric; Cataldo, Laurent; Berclaz, Théo; Geoffroy, Michel; Levillain, Eric; Avarvari, Narcis; Fourmigué, Marc; Sauvage, François X; Wartelle, Corinne

2005-01-01

255

Hydrogenation of cinnamaldehyde using catalysts prepared from supported palladium phosphine complexes  

SciTech Connect

The liquid phase hydrogenation of cinnamaldehyde has been studied using catalysts prepared from the binuclear palladium complexes [Pd{sub 2}X{sub 4}(PR{sub 3}){sub 2}] (X = Cl, Br, or I; R = Me, Et, and Pr{sup i} or Bu for X =Br only) on silica, and the results have been compared with the performance of a standard Pd/SiO{sub 2} catalyst prepared from Pd(NO{sub 3}){sub 2} and with that of the unsupported molecular complexes. When X = Br, cinnamaldehyde is rapidly hydrogenated selectively to hydrocinnamaldehyde and no further reaction occurs. When X = I, the reactions are extremely slow but are again limited to hydrocinnamaidehyde formation. The catalysts prepared from the chloride-containing precursors behave differently, and some phenyl propanol is formed along with hydrocinnamaldehyde. However, the reaction mechanisms are different from that which operates with the silica-supported palladium catalyst. The rates of the reactions are dependent on the nature of the phosphine substituent, but the selectivities are dependent primarily on the halide. Hydrogenation reactions on all of the catalysts prepared from the binuclear complexes proceed only after an induction period during which partial reduction and/or surface reconstruction of the supported complexes occur. This contrasts with the performance of the standard Pd/SiO{sub 2} catalysts for cinnamaldehyde hydrogenation, which proceeds without any induction period. The reactions of all of these catalysts are thought to take place on a hydrocarbonaceous overlayer which is formed rapidly from unsaturated aldehydes and alcohols. Hydrogenations of cinnamaldehyde using the unsupported complexes in solution proceed at much lower rates, but reveal the same selectivities observed with their silica-supported counterparts. 46 refs., 4 figs., 1 tab.

Cairns, G.R.; Cross, R.J.; Stirling, D. [Univ. of Glasgow (United Kingdom)

1997-02-01

256

Synthesis and structure of indenyl rhodium(I) complexes containing unsaturated phosphines: catalyst precursors for alkene hydroboration.  

PubMed

The indenyl compound (eta(5)-C(9)H(7))Rh(coe)(2) (1, coe = cis-cyclooctene) has been prepared as a thermally stable alternative to the diethylene derivative (eta(5)-C(9)H(7))Rh(eta(2)-H(2)C[double bond, length as m-dash]CH(2))(2). Compound 1 reacts with unsaturated phosphines Ph(2)PR (R = CH[double bond, length as m-dash]CH(2), 2; CH(2)CH=CH(2), 3; and C triple bond C-tert-Bu, 4) to give complexes of the type (eta(5)-C(9)H(7))Rh(Ph(2)PR)(2), where bonding occurs through the phosphorus atom. Addition of Ph(2)PC triple bond CPPh(2) to 1 gave the dimer [(eta(5)-C(9)H(7))Rh(micro-Ph(2)PC triple bond CPPh(2))](2) (5). Solution and solid state data showed that these new phosphine complexes have only a moderate amount of distortion within the indenyl ring. These compounds were found to catalyse the hydroboration of vinylarenes and the first example of an internal hydroboration of diphenylvinylphosphine has been reported. PMID:19421607

Garon, Christian N; McIsaac, Daniel I; Vogels, Christopher M; Decken, Andreas; Williams, Ian D; Kleeberg, Christian; Marder, Todd B; Westcott, Stephen A

2009-01-20

257

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

PubMed

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

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

2011-03-07

258

[5,10,15,20-Tetra-kis(4-chloro-phen-yl)porphyrinato]bis-(tributyl-phosphine)cobalt(III) perchlorate  

PubMed Central

In the mol­ecule of the title compound, [Co(C44H24Cl4N4){(C4H9)3P}2]ClO4, the CoIII centre has a slightly distorted octa­hedral geometry and is coordinated by four N atoms of the tetra­pyrrolic ring in the equatorial positions and two phosphine ligands in the axial positions. The dihedral angles between meso-substituted chloro­phenyl rings and the basic tetra­pyrrolic ring are 82.66?(9), 82.16?(7), 83.97?(11) and 76.87?(8)°. In one of the phosphine ligands, the two terminal methyl groups are disordered over two positions with refined site-occupancy ratios of 0.70?(7):0.30?(7) and 0.66?(2):0.34?(2). In the crystal structure, mol­ecules are linked together along the a axis by inter­molecular C—H?Cl inter­actions. The crystal structure is further stabilized by intra­molecular C—H?O and C—H?N inter­actions and inter­molecular C—H?O and C—H?? inter­actions.

Etemadi, Bijan; Kia, Reza; Asadi, Mozaffar; Mohammadi, Kh.

2009-01-01

259

Latitude Variations of the Abundances of Ammonia, Acetylene, and Phosphine and Vertical Mixing in the Atmospheres of Jupiter and Saturn  

NASA Astrophysics Data System (ADS)

Ultraviolet observations of Jupiter and Saturn performed in the past have typically suffered from poor spatial resolution and have therefore focused on either globally-averaged values or north-south asymmetries. Spectra taken with the Hubble Space Telescope Faint Object Spectrograph have a spatial resolution of 1 arc second, making it possible to sample the disk at several latitudes. The observations presented here were taken at latitudes along the Central Meridian of both Jupiter (65oS, 48oS, 33oS, 25oS, 12oS, 6oS, 0o, 6oN, 15oN, 20oN, 25oN, 48oN, 65oN, along with the Great Red Spot and the South Equatorial Belt) and Saturn (4oS, 4oN, 12oN, 20oN, 40oN, 48oN, 60oN, 79oN, 90oN). The wavelength interval covers a range from 180 nm to 240 nm. Albedos have been calculated by dividing the observations by intensity of the Sun at each planet. Removal of solar features reveals the presence of ammonia, acetylene, and continuum absorbers (e.g. phosphine and aerosols). With the use of a photochemical model which includes a multiple scattering radiative transfer code, the altitude profiles of these species have been generated by using the eddy diffusion coefficient as a free parameter. From the altitude profiles, synthetic spectra were calculated and compared with the observations at each latitude. This work reveals that a variation of ammonia, acetylene, phosphine, and the vertical mixing with altitude exists in both atmospheres. The presence of a strong ammonia signature in the Jovian spectra allows it to be used as a tracer for the dynamics near the tropopause. The value of the eddy mixing coefficient at 6oN increases rapidly with depth from a value of 5×102 cm2s-1 to 104 cm2s-1 between 90-150 mbar. Above the 90 mbar level, the value increases reaching a value of 8×102 cm2s-1 at 60 mbar. A latitudinal variation in the ammonia mixing ratio and eddy mixing profile is also derived from the FOS observations. In the northern hemisphere of Jupiter, the ammonia mixing ratio above the tropopause and the eddy mixing are found to decrease as one moves further north. In the southern hemisphere, however, there is more variation with latitude. The strongest vertical mixing and the largest abundance of ammonia is in the Great Red Spot region. On Saturn, phosphine can be assumed to provide the source of opacity for the continuum. Based on this assumption, the vertical distribution of phosphine and eddy mixing coefficients have been derived. The largest mixing ratio of phosphine and the strongest mixing ( 9× 103/ cm2s-1) are found near 12oN, with both decreasing monotonically away from 12oN.

Edgington, Scott G.

260

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

PubMed Central

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

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

2011-01-01

261

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

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

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

262

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

PubMed

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

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

2012-02-20

263

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

PubMed

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

Bryant, David E; Kee, Terence P

2006-05-05

264

The rph1 Gene Is a Common Contributor to the Evolution of Phosphine Resistance in Independent Field Isolates of Rhyzopertha Dominica  

PubMed Central

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.

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

2012-01-01

265

Inorganic Coordination Polymers. XXI. Manganese (II), Cobalt (II), Nickel (II), Copper (II), and Zinc (II) Bis(N-Phenylaminomethyl) Phosphinates. Effects of Coordinating Side Groups.  

National Technical Information Service (NTIS)

The metal (II) bis(bis(N-phenylaminomethyl)phosphinates) M(OP(CH2NHC6H))2-O)2 (with M = Mn, Co, Ni, Cu, and Zn) have been investigated. The manganese, cobalt and nickel derivatives all have similar structures with octahedrally coordinated metal centers, t...

J. L. Eichelberger H. D. Gillman

1977-01-01

266

Highly enantioselective hydrogenation and transfer hydrogenation of cycloalkyl and heterocyclic ketones catalysed by an iridium complex of a tridentate phosphine-diamine ligand.  

PubMed

Ir complexes of chiral phosphine-diamine ligands catalyse the hydrogenation and transfer hydrogenation of aryl-piperidin-4-yl methanones, and ketones bearing both an aryl group and secondary alkyl substituent with up to 98% e.e., and with substrate to catalyst ratios of up to 4000. PMID:24068156

Fuentes, José A; Carpenter, Ian; Kann, Nina; Clarke, Matthew L

2013-10-01

267

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

SciTech Connect

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

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

2011-03-07

268

Evidence for a precursor to decomposition for phosphine adsorption on Rh/Al sub 2 O sub 3 surfaces  

SciTech Connect

Transmission infrared spectroscopy has been used to detect formation of the species PH{sub 2} and PH upon PH{sub 3} adsorption and decomposition on Al{sub 2}O{sub 3}-supported Rh surfaces. In addition, a unique bonding configuration of PH{sub 3} has been identified that is a precursor to this decomposition process. The precursor state displays a v(PH{sub 3}) vibration that is shifted considerably to lower wavenumbers with respect to the chemisorbed state due presumably to two-center bonding. The population of the precursor state is a sensitive function of temperature, exposed surface metal sites, and surface pretreatment, and precedes the initial phosphine decomposition. The P-H stretching vibration characteristic of this precursor state is quite distinct from that of physisorbed PH{sub 3}, chemisorbed PH{sub 3}, or the partial decomposition fragments, PH{sub 2} and PH.

Lu, Guangquan; Crowell, J.E. (Univ. of California, San Diego, La Jolla (USA))

1990-07-26

269

New flame-retardant and optically active poly(amide-imide)s based on N- trimellitylimido-L-amino acid and phosphine oxide moiety in the main chain: synthesis and characterization  

Microsoft Academic Search

Six new flame-retardant and optically active poly(amide-imide)s (PAIs) 5a-f containing phosphine oxide moiety in the main chain were synthesized by the direct polycondensation reaction of six chiral N-trimellitylimido-L-amino acids 3a-f with bis(3- amino phenyl) phenyl phosphine oxide 4 in a medium consisting of N-methyl-2- pyrrolidone (NMP), triphenyl phosphite (TPP), calcium chloride (CaCl 2) and pyridine (Py). The polymerization reactions produced

Khalil Faghihi; Mohsen Hajibeygi

270

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

SciTech Connect

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

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

2006-06-01

271

Latitudinal Distribution of Ammonia and Upper Limits of Acetylene and Phosphine in Jupiter's Upper Troposphere and Lower Stratosphere  

NASA Astrophysics Data System (ADS)

Observations of the northern and southern hemispheres of Jupiter done with the Hubble Space Telescope Faint Object Spectrograph during May 19-25, 1992 and June 6, 1993 have been analyzed. Spectra at latitudes 6deg N, 15deg N, 20deg N, 25deg N, 48deg N, 65deg N, 12deg S, 25deg S, 33deg S, 48deg S, 65deg S, and the equator were taken along the central meridian. In addition features were observed, including an equatorial plume, the Great Red Spot, and the nearby SEB. The data were taken with the G190H grating, which covers a wavelength range of 180-230 nm, with several combinations of the 0.5" and 1" apertures and the red and blue detectors. A photochemical model combining the hydrocarbon, nitrogen, and phosphorus chemical cycles along with a rigorous multiple scattering radiative transfer model has been used to determine the altitude profiles of ammonia, acetylene, and phosphine as a function of latitude which are consistent with the measured albedos. It is found that up to midlatitudes, the altitude profiles of ammonia are fairly uniform with latitude. Hazes at high latitudes and the equatorial plume obscure molecular species and prevent their detection. Upper limits to the abundances of acetylene and phosphine are provided. Comparison of the Great Red Spot with other regions will also be presented. This analysis also yields constraints on the value of the vertical eddy diffusion coefficient between the ammonia cloud top and the tropopause. Our current best estimate for the value of K is 1.4x10(3) cm(2) s(-1) at 40 km above the 1 bar level and 1.5x10(4) cm(2) s(-1) at 17 km above 1 bar.

Edgington, S. G.; Atreya, S. K.; Trafton, L. M.; Caldwell, J. J.; Beebe, R. F.; Simon, A. A.; West, R. A.; Barnet, C.

1996-09-01

272

A gold(I) phosphine complex selectively induces apoptosis in breast cancer cells: implications for anticancer therapeutics targeted to mitochondria.  

PubMed

Bis-chelated gold(I) phosphine complexes have shown great potential as anticancer agents, however, their efficacy has been limited by their high toxicity and lack of selectivity for cancer cells. Here, we have investigated the anticancer activity of a new bis-chelated Au(I) bidentate phosphine complex of the novel water soluble ligand 1,3-bis(di-2-pyridylphosphino)propane (d2pypp). We show that this gold complex [Au(d2pypp)(2)]Cl, at submicromolar concentrations, selectively induces apoptosis in breast cancer cells but not in normal breast cells. Apoptosis was induced via the mitochondrial pathway, which involved mitochondrial membrane potential depolarisation, depletion of the glutathione pool and caspase-3 and caspase-9 activation. The gold lipophilic complex was accumulated in mitochondria of cells, driven by the high mitochondrial membrane potential. To address the molecular basis of the observed selectivity between the two cell lines we investigated the effect of the gold complex on the thioredoxin/thioredoxin reductase system in normal and cancer breast cells. We show that [Au(d2pypp)(2)]Cl inhibits the activities of both thioredoxin and thioredoxin reductase and that this effect is more pronounced in the breast cancer cells. This difference may account for the selective cell death seen in the breast cancer cells but not in the normal cells. Our investigation has led to new insights into the mechanism of action of bis-chelated gold(I) diphosphine complexes and their future development as mitochondria targeted chemotherapeutics. PMID:17697672

Rackham, Oliver; Nichols, Scott J; Leedman, Peter J; Berners-Price, Susan J; Filipovska, Aleksandra

2007-07-21

273

The ?(OH/OD) band shape of strong hydrogen bonded dimers of phosphinic acids. Phenomenology and formation models  

NASA Astrophysics Data System (ADS)

The infrared spectra of phosphinic acid R2POOH dimers (R=CH3, CH2Cl, C6H5) have been studied in CCl4 and CH2Cl2 solutions (T=300 K). The infrared spectra of deuterated R2POOD dimers (R=CH3, CH2Cl) were also studied in the gas phase (T=400 550 K) and solid state (T=100 300 K). They are compared with previously studied spectra of the light (non-deuterated) dimers in the gas phase, in the solid state and in low-temperature argon matrices (T=12 30 K) in the 4000 400 cm-1 spectral region. It is found that the strong and broad ?(OH) dimer bands have similar shapes, nearly equal values of bandwidth and low-frequency shift, and possess the Hadzi ABC structure irrespective of the type of acid, significant differences of dimerization enthalpies, influence of solvent, the type of H-bonded complexes (cyclic dimers in the gas phase, in solutions, and in inert matrices, and infinite chains in the solid state), and temperature in the range 12 600 K. Isotopic ratio of the first moments of light and deuterated acid bands has been measured. Analysis of the ?(OH/OD) band of hydrogen bonded dimers of phosphinic acids shows that the interaction between the two intermolecular bonds O H?OP in a cyclic complex plays virtually no role in the mechanism of the ?(OH/OD) band formation; the shape of ?(OH/OD) band is controlled mainly by the POOH(D)?O fragment; and the band shape of strong hydrogen bonded complexes is formed by a number of vibrational transitions from the ground state to different combination levels in the region 3500 1500 cm-1.

Asfin, R. E.; Denisov, G. S.; Tokhadze, K. G.

2006-06-01

274

Transition metal complexes of primary and secondary phosphines, part II. Some palladium(II) and platinum(II) complexes of type L 3 MC 2  

Microsoft Academic Search

Summary The general course of reactions between [MCl4 ]2- (M = Pd, Pt) and primary and secondary phosphines containing phenyl, cyclohexyl, or 2-cyanoethyl groups, in polar solvents, is to yield L3MCl2 complexes which are probably ionic [L3MCl]+Cl- These compounds can be isolated and characterized in the solid state, but in solution they are labile, and tend to react to give

Satya P. Anand; Harold Goldwhite; John R. Spielman

1977-01-01

275

Triphenyl-phosphine oxide-2-(4-hydroxy-benzen-yl)-4,4,5,5-tetra-methyl-imidazolidine-1-oxyl 3-oxide (1/1)  

PubMed Central

The title compound, C18H15OP·C13H17N2O3, belongs to a series of mol­ecular systems based on triphenyl­phosphine oxide. The O atom of the oxide group acts as an acceptor for hydrogen bonds from –OH groups of the nitronyl nitroxide. The crystal structure is stabilized by O—H?O hydrogen bonds.

Jing, Lin-Lin; Wang, Hai-Bo; Sun, Xiao-Li

2009-01-01

276

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

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

E. Makrlík; P. Va?ura; P. Selucký

2009-01-01

277

The infrared spectra and enthalpies of strongly bound dimers of phosphinic acids in the gas phase. (CH 2Cl) 2POOH and (C 6H 5) 2POOH  

Microsoft Academic Search

Infrared spectra of phosphinic acids R2POOH (R=CH2Cl, C6H5 and CH3) have been recorded in the gas phase. The equilibrium between monomers and dimers of R2POOH is studied in the temperature range of 400–650K. The broad absorption band in the region 3600–900cm?1 is assigned to the ?(OH) stretching vibration of the very strongly bound cyclic dimer. The characteristic ABC structure of

R. E Asfin; G. S Denisov; K. G Tokhadze

2002-01-01

278

Application of Highly Efficient, Recyclable Organic–Inorganic Hybrid Material Immobilized Palladium Catalyst in Amine? and Phosphine?Free Suzuki–Miyaura Reaction  

Microsoft Academic Search

Palladium immobilized on organic–inorganic (silica?gel) hybrid materials behaves as a very efficient heterogeneous catalyst in the Suzuki–Miyaura coupling reaction. Aryl iodides, bromides, and activated chlorides, coupled with organoboronic acids (Suzuki–Miyaura reaction), smoothly afford the corresponding cross?coupling products in excellent yields under phosphine?free and amine?free reaction conditions in the presence of 3?aminopropyl functionalized silica?gel immobilized palladium (silica?APTS?Pd) as catalyst. Furthermore, the

Liyuan Zhang; Lei Wang; Hongji Li; Pinhua Li

2008-01-01

279

Study of Electron Donor–Acceptor Complex Formation of o Chloranil With a Series of Phosphine Oxides and Tri n -butyl Phosphate by the Absorption Spectrometric Method  

Microsoft Academic Search

Electron donor–acceptor (EDA) complex formation of o-chloranil with six different phosphine oxides and tri-n-butyl phosphate (TBP) has been studied in CCl 4 solution by the UV-VIS absorption spectrophotometric technique. An absorption band due to a charge–transfer (CT) transition is observed in the visible region. Utilizing the CT transition energy, the electron affinity of o-chloranil in solution has been calculated. Degrees

Sumanta Bhattacharya; Shrabanti Bhattacharya Banerjee; Kalyan Ghosh; Sukalyan Basu; Manas Banerjee

2006-01-01

280

Reactions of Elemental Phosphorus and Phosphines with Electrophiles in Superbasic Systems: XIII. Phosphorylation of Phenylacetylene with Active Modifications of Elemental Phosphorus  

Microsoft Academic Search

Phosphorylation of phenylacetylene with white or activated red phosphorus (prepared from white phosphorus under the action of ionizing radiation) occurs in KOH-DMSO or KOH-HMPA systems with heat evolution and stereoselective formation of Z isomers of tristyrylphosphine and -phosphine oxide in yields of 48-49% and 10-15%, respectively. Under the comparable conditions the commercial red phosphorus is considerably less reactive toward phenylacetylene:

N. K. Gusarova; B. G. Sukhov; S. F. Malysheva; T. I. Kazantseva; Yu. V. Smetannikov; N. P. Tarasova; B. A. Trofimov

2001-01-01

281

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

SciTech Connect

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

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

2009-06-01

282

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

Microsoft Academic Search

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%.

N. S. Awwad; E. H. Borai

2009-01-01

283

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

Microsoft Academic Search

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

Hua Ren; Jianzhong Sun; Binjie Wu; Qiyun Zhou

2007-01-01

284

Antitumor activity of the mixed phosphine gold species chlorotriphenylphosphine-1,3-bis(diphenylphosphino)propanegold(I).  

PubMed

The title compound has been designed for antitumor activity based on structural features of related known antitumor gold agents, that is, gold-monophosphine and gold-diphosphine derivatives. It is a gold complex that contains both types of phosphine ligands, thus suggesting a possible synergistic action. The results of a single crystal X-ray structure determination of this molecule show the metal surrounded by 3 P atoms and one Cl anion in a distorted tetrahedral arrangement. The chloro anion, however, is weakly bound to the metal and so the species shows ionic character. The P NMR study, performed in solution, confirms the structural features observed in the solid and, in addition, indicates partial formation of other known gold(I)-diphosphine antitumor agents. The ionic character and strong Au-P bonds of this novel gold(I) species are similar to those of the most active antitumor gold compounds so far studied. The former feature contributes to solubility in biological fluids, and the latter prevents fast biomolecular attack. In addition, the title compound is less lipophilic, a feature recently correlated to lower liver toxicity. The title compound shows in vitro antitumor activity in the two initial National Cancer Institute protocols against human tumors. In the first screening, a unique dose (0.10 mM) of the title compound reduced cell growth of MCF7 (breast cancer), NCI-H460 (lung cancer), and SF-268 (Central Nervous System cancer-CNS) to 5, 8, and 11%, respectively. In the second protocol a 60-cell line panel was analyzed with the title compound concentration in the 0.1 mM-0.01 microM range. The highest activity was for the breast tumor cell line MCF7 with a LC(50) less than 0.01 microM. LC(50) values in the micromolar range were obtained for 29 cell lines. With the exception of leukemia, these micromolar activities were observed in at least one cell line for each subgroup tumor (non small lung, colon, CNS, melanoma, renal, prostate, breast, and ovarian). The leukemia inactivity was unexpected, as all antitumor gold(I) phosphine compounds in the literature described thus far are active. Melanoma was the most sensitive subgroup screened (five out of seven cell lines). PMID:12699391

Caruso, Francesco; Rossi, Miriam; Tanski, Joseph; Pettinari, Claudio; Marchetti, Fabio

2003-04-24

285

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

PubMed

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

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

2011-07-16

286

Use of phosphine as an n-type dopant source for vapor-liquid-solid growth of silicon nanowires.  

PubMed

Phosphine (PH3) was investigated as an n-type dopant source for Au-catalyzed vapor-liquid-solid (VLS) growth of phosphorus-doped silicon nanowires (SiNWs). Transmission electron microscopy characterization revealed that the as-grown SiNWs were predominately single crystal even at high phosphorus concentrations. Four-point resistance and gate-dependent conductance measurements confirmed that electrically active phosphorus was incorporated into the SiNWs during VLS growth. A transition was observed from p-type conduction for nominally undoped SiNWs to n-type conduction upon the introduction of PH3 to the inlet gas. The resistivity of the n-type SiNWs decreased by approximately 3 orders of magnitude as the inlet PH3 to silane (SiH4) gas ratio was increased from 2 x 10(-5) to 2 x 10(-3). These results demonstrate that PH3 can be used to produce n-type SiNWs with properties that are suitable for electronic and optoelectronic device applications. PMID:16277441

Wang, Yanfeng; Lew, Kok-Keong; Ho, Tsung-Ta; Pan, Ling; Novak, Steven W; Dickey, Elizabeth C; Redwing, Joan M; Mayer, Theresa S

2005-11-01

287

Gas sorption and luminescence properties of a terbium(III)-phosphine oxide coordination material with two-dimensional pore topology.  

PubMed

The structure, stability, gas sorption properties and luminescence behaviour of a new lanthanide-phosphine oxide coordination material are reported. The polymer PCM-15 is based on Tb(III) and tris(p-carboxylated) triphenylphosphine oxide and has a 5,5-connected net topology. It exhibits an infinite three-dimensional structure that incorporates an open, two-dimensional pore structure. The material is thermally robust and remains crystalline under high vacuum at 150 °C. When desolvated, the solid has a CO(2) BET surface area of 1187 m(2) g(-1) and shows the highest reported uptake of both O(2) and H(2) at 77 K and 1 bar for a lanthanide-based coordination polymer. Isolated Tb(III) centres in the as-synthesized polymer exhibit moderate photoluminescence. However, upon removal of coordinated OH(2) ligands, the luminescence intensity was found to approximately double; this process was reversible. Thus, the Tb(III) centre was used as a probe to detect directly the desolvation and resolvation of the polymer. PMID:22450857

Ibarra, Ilich A; Hesterberg, Travis W; Holliday, Bradley J; Lynch, Vincent M; Humphrey, Simon M

2012-03-27

288

Nickel complexes incorporating an amido phosphine chelate with a pendant amine arm: synthesis, structure, and catalytic Kumada coupling.  

PubMed

A series of organonickel(II) complexes incorporating an amido phosphine ligand tethered with an amino pendant have been prepared and characterized. Deprotonation of N-(dimethylaminoethyl)-2-diphenylphosphinoaniline (H[PNN]) with one equivalent of n-BuLi in ethereal or hydrocarbon solutions at -35 °C generates cleanly dimeric {Li[PNN]}(2) as yellow crystals. The reaction of NiCl(2)(DME) with {Li[PNN]}(2) in THF at -35 °C affords green crystalline [PNN]NiCl. Treating [PNN]NiCl with NaX in acetone solutions gives [PNN]NiX (X = Br, I). Alkylation or arylation of [PNN]NiCl with appropriate Grignard reagents in THF at -35 °C produces red crystalline [PNN]NiR (R = Me, Et, i-Bu, n-hexyl, CH(2)Ph, Ph). The chloride complex [PNN]NiCl was found to be an active catalyst precursor for Kumada coupling reactions of PhX (X = I, Br, Cl) with aryl or alkyl Grignard reagents, including those containing ?-hydrogen atoms. The X-ray structures of {Li[PNN]}(2) and [PNN]NiX (X = Cl, Br, Me, Et, n-hexyl) are reported. PMID:22124467

Liang, Lan-Chang; Lee, Wei-Ying; Hung, Yu-Ting; Hsiao, Yi-Chen; Cheng, Liang-Chien; Chen, Wei-Chen

2011-11-29

289

Study of the phosphine plasma decomposition and its formation by ablation of red phosphorus in hydrogen plasma  

NASA Astrophysics Data System (ADS)

Mass spectrometry and optical emission spectroscopy have been used to study the chemistry of PH(sub 3) plasma decomposition as well as its formation by ablation of red phosphorus in hydrogen plasma. It has been shown that PH(sub 3) decomposition easily equilibrates at low levels of PH(sub 3) depletion (15%-30%), this depending mainly on the rf power. The ablation of red phosphorus in H(sub 2) plasma produces phosphine in significant amount, depending mainly on the total pressure but also on the rf power. It has also been found that H(sup *) and PH(sup *) emitting species originate not only by the dissociative excitation of H(sub 2) and PH(sub 3), respectively, but also by the direct excitation of the same species in the ground state. Considerations are developed on how to derive the H-atom and PH radical densities by actinometry, under specific experimental conditions. Besides, the linear dependence of PH(sub 3) formation rate, r(sub PH(3)), on H-atom density, (left bracket) H (right bracket), leads to the definition of the kinetic equation r(sub PH(3)) = k (left bracket) H (right bracket), and to the hypothesis that the formation of PH radical on the surface or its desorption is the dominant mechanism for PH(sub 3) production.

Bruno, G.; Losurdo, M.; Capezzuto, P.

1995-03-01

290

Organometallic oligomers based on bis(arylacetylide)bis(P-chirogenic phosphine)platinum(II) complexes: synthesis and photonic properties.  

PubMed

A series of P-chirogenic oligomers of the type (-C?C-aryl-C?C-PtL2-)n [L = (R)- and (S)-P(Ph)(iPr)(C17H35); aryl = 1,4-benzene, 2,1,3-benzothiadiazole] along the corresponding achiral analogues (L = PBu3) and model complexes PhC?CPtL2C?CPh were prepared from the ephedrine strategy and were fully characterized [(1)H, (31)P NMR; IR; small-angle X-ray scattering (SAXS); gel permeation chromatography (GPC); thermal gravimetric analysis (TGA); circular dichroism, UV-vis, and luminescence spectroscopy; photophysics, and degree of anisotropy measurements]. From the CD measurements, the chiral environment of the phosphine ligands is modestly felt by the aryl moieties. Concurrently, the TGA shows that the P(C17H35)(Ph)(i-Pr)-containing materials are more stable than those containing the shorter chain ligand PBu3, and exhibits red-shifted absorption and emission bands compared to those including the PBu3 ligands. The presence of the long chain on the phosphorus atoms does not greatly alter the photophysical parameters, notably the emission lifetimes, and fast triplet energy transfer terminal* ? central unit has been deduced from the absence of luminescence arising from the terminal units. PMID:23421769

Lapprand, Antony; Khiri, Naïma; Fortin, Daniel; Jugé, Sylvain; Harvey, Pierre D

2013-02-19

291

Development of ruthenium catalysts for the enantioselective synthesis of P-stereogenic phosphines via nucleophilic phosphido intermediates.  

PubMed

This work details the development of ruthenium(II) catalysts for the enantioselective alkylation of chiral racemic secondary phosphines. The reactions proceed through the intermediacy of nucleophilic phosphido species, which have low barriers to pyramidal inversion; this allows for a dynamic kinetic asymmetric alkylation. The initially discovered [((R)-iPr-PHOX)(2)Ru(H)][BPh(4)] (6) catalyst was found to be effective in the reaction with benzylic chlorides; moreover, the alkylation displayed an unusual temperature dependence. However, the limited scope of alkylation of 6 motivated further studies which led to the development of two complementary chiral mixed ligand Ru(II) catalysts of type [L(1)L(2)Ru(H)](+). These catalysts were derived from a combination of one chiral and one achiral ligand, where a synergistic interaction of the two ligands creates an effective asymmetric environment around the ruthenium center. The (R)-MeO-BiPHEP/dmpe (dmpe = 1,2-bis(dimethylphosphino)ethane) catalyst (10) was found to be effective for the asymmetric alkylation of benzylic chlorides, while the (R)-DIFLUORPHOS/dmpe catalyst (11) was optimal for the nucleophilic substitution of less activated alkyl bromides; the scope of the respective catalysts was also explored. PMID:19338305

Chan, Vincent S; Chiu, Melanie; Bergman, Robert G; Toste, F Dean

2009-04-29

292

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

SciTech Connect

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

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

2010-01-12

293

Competitive and selective Csp3-Br versus Csp2-Br bond activation in palladium-catalysed Suzuki cross-coupling: an experimental and theoretical study of the role of phosphine ligands.  

PubMed

Phosphine ligands have been demonstrated to have an effect on reactivity and selectivity in the competitive intramolecular palladium-catalysed Suzuki-Miyaura coupling of dibromo sulfoxide 1a possessing two different hybridised electrophilic carbons. It was found that the bromine bond to the sp(3)-hybridised carbon is selectively replaced in the presence of unhindered phosphines such as PPh(3) or xantphos. The use of hindered phosphine ligands such as P(o-tol)(3) and P(1-naphthyl)(3) reversed the selectivity, conducting the cross-coupling at the Csp(2)-Br. Identical trends were observed in external competition experiments carried out with bromomethyl sulfoxide and different substituted bromoarenes. DFT and DFT/MM calculations showed that the selectivity observed is mainly due to the different facility of the ligands to dissociate. Bisphosphine catalysts favour coupling at the sp(3) carbon, whereas monophosphine catalysts prefer the sp(2) carbon. PMID:20931565

Mollar, Cristian; Besora, Maria; Maseras, Feliu; Asensio, Gregorio; Medio-Simón, Mercedes

2010-12-01

294

Synthesis and oxidation of chiral rhenium phosphine methyl complexes of the formula (? 5-C 5Me 5)Re(NO)(PR 3)(CH 3): in search of radical cations with enhanced kinetic stabilities  

Microsoft Academic Search

Reactions of racemic [(?5-C5Me5)Re(NO)(NCCH3)(CO)]+ BF4? and phosphines PR3 (R=C6H5a; 4-C6H4CH3b; 4-C6H4-t-C4H9c; 4-C6H4C6H5d; 4-C6H4OCH3e; c-C6H11f) give the phosphine carbonyl complexes [(?5-C5Me5)Re(NO)(PR3)(CO)]+ BF4? (5a–5f+ BF4?; 55–95%). These are treated with LiEt3BH and then BH3·THF to give the phosphine methyl complexes (?5-C5Me5)Re(NO)(PR3)(CH3) (2a–2f, 50–86%). Cyclic voltammetry shows that the new compounds 2b–2f undergo chemically reversible one-electron oxidations that are thermodynamically more favorable than

Wayne E Meyer; Angelo J Amoroso; Monika Jaeger; Jean Le Bras; Wing-Tak Wong; J. A Gladysz

2000-01-01

295

Molecular Control of the Nanoscale: Effect of Phosphine–Chalcogenide Reactivity on CdS–CdSe Nanocrystal Composition and Morphology  

SciTech Connect

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 (31P and 77Se), 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: TPPE < DPPE < TBPE < TOPE < HPTE (E = S, Se). For a given phosphine, the selenide is always more reactive than the sulfide. CdS1–xSex quantum dots were synthesized via single injection of a R3PS–R3PSe 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 R3PS and R3PSe reactivity dictates CdS1–xSex dot chalcogen content and the extent of radial alloying (alloys vs core/shells). CdS, CdSe, and CdS1–xSex quantum rods were synthesized by injection of a single R3PE (E = S or Se) precursor or a R3PS–R3PSe 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 R3PE precursor reactivity. Purposely matching or mismatching R3PS–R3PSe precursor reactivity leads to CdS1–xSex 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.

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

2012-04-22

296

Optically active and flame-retardant poly(amide-imide)s based on phosphine oxide moiety and N,N ?-(pyromellitoyl)bis-l-amino acid in the main chain: Synthesis and characterization  

Microsoft Academic Search

Six new optically active and flame-retardant poly(amide-imide)s PAIs 5a–5f containing phosphine oxide moiety as a flame-retardant unit in the main chain were synthesized from direct polycondensation\\u000a reaction of six chiral N,N?-(pyromellitoyl)-bis-L-amino acid 3a–3f with bis(3-aminophenyl)phenyl phosphine oxide 4 in a medium consisting of N-methyl-2-pyrrolidone (NMP), triphenyl phosphite (TPP), calcium chloride (CaCl2) and pyridine. The polymerization reactions produced a series of

Khalil Faghihi; Mohsen Hajibeygi

2010-01-01

297

Reactions of elemental phosphorus and phosphine with electrophiles in superbasic systems: XVIII. Phosphorylation of 1-(chloromethyl)naphthalene with the elemental phosphorus  

Microsoft Academic Search

1-Chloromethylnaphthalene reacts with white and red phosphorus, and also with the “activated red phosphorus,” the complex\\u000a organophosphorus polymer of unknown structure obtained by irradiation of a solution of white phosphorus in benzene by the\\u000a 60Co source, in a system including KOH water solution, dioxane or benzene, and a phase transfer catalyst (22–98C, argon), to\\u000a form bis(1-naphthylmethyl)-and tris-(1-naphthylmethyl)phosphine oxides, and also

V. A. Kuimov; N. K. Gusarova; S. F. Malysheva; B. G. Sukhov; Yu. V. Smetannikov; N. P. Tarasova; A. V. Gusarov; B. A. Trofimov

2006-01-01

298

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

SciTech Connect

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

Nogami, M.; Sugiyama, Y.; Ikeda, Y. [Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, 2-12-1-N1-34 O-okayama, Meguro-ku, Tokyo 152-8550 (Japan); Maruyama, K. [Mitsubishi Chemical, Corp., 1000 Kamoshida-cho, Aoba-ku, Yokohama 227-8502 (Japan)

2008-07-01

299

Application of chelate phosphine oxide ligand in EuIII complex with mezzo triplet energy level, highly efficient photoluminescent, and electroluminescent performances.  

PubMed

The chelate phosphine oxide ligand bis(2-(diphenylphosphino)phenyl) ether oxide (DPEPO) was used as a unit neutral ligand to prepare the complex Eu(TTA)(3)(DPEPO) 1 (TTA = 2-thenoyltrifluoroacetonate). Compound 1 has a photoluminescence (PL) quantum yield of 55.3%, which is more than the twice of the PL quantum yield of Eu(TTA)(3)(TPPO)(2) (TPPO = triphenylphosphine oxide). Investigation indicated that DPEPO in 1 has the mezzo first triplet excited energy level (T(1)) between the first singlet excited energy level (S(1)) and T(1) of TTA, which may support one more additional energy transfer routines from the T(1) energy level of DPEPO to that of TTA, and consequently results in the improvement of energy transfer in the Eu(III) complex. DPEPO forms a complex with a more rigid and compact structure that can improve energy transfer between ligands and the center Eu(III) ion, support the higher saturation level by the coordinating ability of the oxygen atom in the ether moiety, and consequently enhance the PL intensity and efficiency of the corresponding Eu(III) complex. The multilayered electroluminescent (EL) device of 1 used as the red dopant exhibited an impressive brightness of 632 cd m(-2) at 25 V. The device had the excellent voltage-independent spectral stability with an emission peak at 615 nm. To the best of our knowledge, this luminescence is the brightest emission among Eu complexes with phosphine oxide ligands. The maximum external quantum yield (eta(ext)) of 2.89% and the maximum current and power efficiency of 4.58 cd A(-1) and 2.05 lm W(-1) were achieved at a low turn-on voltage of 7 V and current density of 0.021 mA cm(-2). These properties demonstrate that the chelate phosphine oxides ligand DPEPO can not only be favorable to form the rigid and compact complex structure and increase the efficiency of devices, but also reduce the ability of the formation of exciplex. DPEPO shows much better performance compared with the ordinary phosphine oxide ligand triphenylphosphine oxide. PMID:16494304

Xu, Hui; Wang, Lian-Hui; Zhu, Xu-Hui; Yin, Kun; Zhong, Gao-Yu; Hou, Xiao-Yuan; Huang, Wei

2006-02-23

300

Dihydro-nium hexa-kis[bromido/chlorido(0.75/0.25)]dicadmate(II)-triphenyl-phosphine oxide (1/6)  

PubMed Central

In the salt, (H3O)2[Cd2Br4.5Cl1.5]·6C18H15OP, the hydro­nium cation forms short O—H?O hydrogen bonds to the O atoms of the triphenyl­phosphine oxide units. The centrosymmetric dinuclear anion has two halide atoms functioning in a bridging mode, which confers tetra­hedral coordination to the Cd atom. The three independent halide atoms are each a mixture of bromide and chloride; the occupancies of the Br atoms are 0.6434?(11), 0.7468?(11) and 0.8598?(11).

Lo, Kong Mun; Ng, Seik Weng

2009-01-01

301

An efficient palladium-benzimidazolyl phosphine complex for the Suzuki-Miyaura coupling of aryl mesylates: facile ligand synthesis and metal complex characterization.  

PubMed

A new class of easily accessible hemilabile benzimidazolyl phosphine ligands has been developed. The ligand skeleton is prepared from commercially available and inexpensive o-phenylenediamine and 2-bromobenzoic acid. With catalyst loading down to 0.5 mol% palladium, excellent catalytic activity towards the Suzuki-Miyaura coupling of aryl mesylates is still observed. This represents the lowest catalyst loading achieved so far for this reaction in general. X-Ray crystallography shows that new ligand L2 is coordinated with Pd in a ?(2)-P,N fashion. PMID:22234641

Chung, Kin Ho; So, Chau Ming; Wong, Shun Man; Luk, Chi Him; Zhou, Zhongyuan; Lau, Chak Po; Kwong, Fuk Yee

2012-01-11

302

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

PubMed

Adducts of a number of tertiary pnicogen ligands ER(3) (triphenyl-phosphine and -arsine (PPh(3),AsPh(3)), diphenyl,2-pyridylphosphine (PPh(2)py), tris(4-fluorophenyl)phosphine (P(C(6)H(4)-4F)(3)), tris(2-tolyl)phosphine (P(o-tol)(3)), tris(cyclohexyl)phosphine (PCy(3))), with silver(I) thiocyanate, AgSCN are structurally and spectroscopically characterized. The 1:3 AgSCN?:?ER(3) complexes structurally defined (for PPh(3),AsPh(3) (diversely solvated)) take the form [(R(3)E)(3)AgX], the thiocyanate X = NCS being N-bound, thus [(Ph(3)E)Ag(NCS)]. A 1:2 complex with PPh(2)py, takes the binuclear form [(pyPh(2)P)(2)Ag()Ag(PPh(2)py)(2)] with an eight-membered cyclic core. 1:1 complexes are defined with PPh(2)py, P(o-tol)(3) and PCy(3); binuclear forms [(R(3)P)Ag()Ag(PR(3))] are obtained with P(o-tol)(3) (two polymorphs), while novel isomeric tetranuclear forms, which may be envisaged as dimers of dimers, are obtained with PPh(2)py, and, as further polymorphs, with PCy(3); these latter may be considered as extensions of the 'cubane' and 'step' forms previously described for [(R(3)E)AgX](4) (X = halide) complexes. Solvent-assisted mechanochemical or solvent-assisted solid-state synthesis methods were employed in some cases, where complexes could not be obtained by conventional solution methods, or where such methods yielded a mixture of polymorphs unsuitable for solid-state spectroscopy. The wavenumbers of the ?(CN) bands in the IR spectra are in broad agreement with the empirical rule that distinguishes bridging from terminal bonding, but exceptions occur for compounds that have a double SCN bridged dimeric structure, and replacement of PPh(3) with PPh(2)py apparently causes a significant decrease in ?(CN) to well below the range expected for bridging SCN in these structures. (31)P CP MAS NMR spectra yield additional parameters that allow a correlation between the structures and spectra. PMID:23114624

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

2013-01-01

303

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

PubMed

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

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

2012-10-19

304

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

SciTech Connect

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

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

2009-12-10

305

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

SciTech Connect

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

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

1986-07-01

306

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

PubMed

A combined catalyst system of a cinchonidine-derived primary amine and triphenylphosphine (CD-NH2 /PPh3 ) exhibited high catalytic performance in the Michael reaction of aldehydes with maleimides, thereby affording the corresponding functionalized aldehydes in excellent yields (up to 99?%) and enantioselectivities (>99?% ee). More interestingly, the significance of the phosphine in enhancing the enantioselectivities in the chiral-primary-amine-catalyzed Michael reaction was revealed. Furthermore, we explored the origin of the reaction mechanism in the Michael addition promoted by the dual organocatalytic system. On the basis of experimental results and spectroscopic analysis, such as UV/Vis, fluorescence emission (FL), NMR, and circular dichroism (CD) spectroscopy, as well as ESI-MS, we found that the molecular assembly of phosphine and primary amine played a crucial role in this enantioselective reaction, in which a possible supramolecular complex was formed as an effective chiral catalyst through noncovalent molecular interactions of a cinchona alkaloid-derived primary amine with triphenylphosphine. PMID:23554319

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

2013-04-03

307

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

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

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

2012-06-22

308

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

PubMed Central

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

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

2010-01-01

309

Copper-catalyzed B-h bond insertion reaction: a highly efficient and enantioselective C-B bond-forming reaction with amine-borane and phosphine-borane adducts.  

PubMed

A copper-catalyzed B-H bond insertion reaction with amine- and phosphine-borane adducts was realized with high yield and enantioselectivity under mild reaction conditions. The B-H bond insertion reaction provides a new C-B bond-forming methodology and an efficient approach to chiral organoboron compounds. PMID:24025045

Cheng, Qing-Qing; Zhu, Shou-Fei; Zhang, Yong-Zhen; Xie, Xiu-Lan; Zhou, Qi-Lin

2013-09-13

310

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

PubMed

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

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

2006-10-10

311

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

PubMed

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

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

2012-10-16

312

Extraction of Am(III), Eu(III) and U(VI) from perchloric acid and mixtures of acids by dialkyl-(diaryl) [diethylcarbamoylmethyl] phosphine oxides  

SciTech Connect

Extraction of Am(III), and Eu(III) and U(VI) from perchloric acid solutions by dialkyl(diaryl) [diethyl-carbamoylmethyl] phosphine oxides (CMPO) has been investigated. It has been shown that elements are extracted more effectively from perchloric acid solutions than from nitric acid. An `anomalous aryl effect` increases sufficiently in perchloric media as compared with nitric media. Solvate numbers of elements also increase in perchloric acid, they being extremely high for aryl-substituted reagents and not so high for alkyl-substituted compounds. It has been shown that in HNO{sub 3} and HClO{sub 4} solutions the value of `anomalous aryl effect` directly depends on the difference in values of element solvate numbers in complexes with aryl- and alkyl-substituted CMPO. Am(III), Eu(III) and U(VI) are not practically extracted from phosphoric and sulphuric acids by CMPO solutions. 16 refs., 7 figs., 3 tabs.

Chmutova, M.K.; Litvina, M.N.; Nesterova, N.P.; Myasoedov, B.F.; Kabachnik, M.I. [Vernadsky Inst. of Geochemistry and Analytical Chemistry, Moscow (Russian Federation)

1992-07-01

313

Tris{N-[bis-(dimethyl-amino)phosphino-yl]-2,2,2-trichloro-acetamido}(triphenyl-phosphine oxide)holmium(III)  

PubMed Central

In the title compound, [Ho(C6H12Cl3N3O2P)3(C18H15OP)], the HoIII ion is surrounded by six O atoms from the three bidentate N-[bis­(dimethyl­amino)phosphino­yl]-2,2,2-trichloro­acetamido ligands (L ?) and by one O atom from the triphenyl­phosphine oxide ligand, with the formation of a distorted monocapped octa­hedron. In one ligand L ?, the trichloro­methyl group is rotationally disordered between two orientations in a 1:1 ratio, while two dimethyl­amino groups in another ligand L ? are disordered between two conformations, each with the same 1:1 ratio.

Amirkhanov, Oleksiy V.; Marchenko, Ivan O.; Moroz, Olesia V.; Sliva, Tetyana Yu.; Fritsky, Igor O.

2010-01-01

314

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

SciTech Connect

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

Suresh, A.; Brahmmananda Rao, C.V.S.; Sabharwal, K.N.; Srinivasan, T.G.; Vasudeva Rao, P.R. [Indira Gandhi Centre for Atomic Research, Kalpakkam (India). Fuel Chemistry Div.

1999-01-01

315

Reactions of palladium complex of N, N-dimethylbenzylamine with aromatic phosphines bearing the methoxy groups at the 2,6-positions  

Microsoft Academic Search

Reactions of [(C6H4CH2NMe2-C2,N)PdCl]2 (1) with (2,6-dimethoxyphenyl)diphenylphosphine (MDMPP), bis(2,6-dimethoxyphenyl)phenylphosphine (BDMPP), and tris(2,6-dimethoxyphenyl)phosphine (TDMPP) gave the corresponding complexes [(C6H4CH2NMe2-C2,N)PdCl(L)] (2a: L=MDMPP; 2b: L=BDMMP; 2c: L=TDMPP). Reactions of 2 with NaPF6 led to replacement of the Cl atom with the methoxy-O atom to form the corresponding complexes [(C6H4CH2NMe2-C2,N)Pd(L)](PF6) (3). On treatment of 3 with HCl (aq), protonation occurred at the N atom in

Jian-Fang Ma; Yasushi Kojima; Yasuhiro Yamamoto

2000-01-01

316

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

PubMed

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

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

2013-09-26

317

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

NASA Astrophysics Data System (ADS)

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

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

2013-09-01

318

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

PubMed

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

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

2013-05-15

319

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

NASA Astrophysics Data System (ADS)

Pd-bis(azido) compounds [Pd(dppn)(N3)2] and [Pd(dppf)(N3)2], which contain bulky chelating bis(phosphine) ligands (dppn=1,8-bis(diphenylphosphino)naphthalene, dppf=1,1?-bis(diphenylphosphino)ferrocene), were prepared from the corresponding chlorides and NaN3. We also prepared the Pt-bis(azido) compound [Pt(1-dpn)(SMe2)(N3)2] containing a bulky monodentate phosphine (1-dpn=1-diphenylphosphino-naphthalene). All these compounds underwent [2+3] cycloaddition with isocyanides (R NC, R=cyclohexyl, tert-butyl, 2,6-dimethylphenyl) to convert azido ligands to five-membered, C-coordinated tetrazolate rings. In addition, we observed the [Pd(dppn)Cl2]-mediated C C coupling of PhCCH to generate the ?2-PhCC CCPh ligand. All compounds have been structurally characterized by X-ray diffraction.

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

2006-05-01

320

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

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.

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

1994-06-01

321

Coupled transport of Zn(II) through a supported liquid membrane containing bis (2,4,4-trimethylpentyl) phosphinic acid in kerosene. II experimental evaluation of model equations for rate process under different limiting conditions  

Microsoft Academic Search

The kinetics of the permeation of Zn(II) from its aqueous solution through a solid supported liquid membrane containing bis(2,4,4-trimethyl pentyl) phosphinic acid (cyanex 272) solution in kerosene has been studied under different experimental conditions. The metal ion flux across the membrane is found to be dependent upon the concentrations of Zn(II) and H+ in the feed solution and carrier in

S. B. Kunungo; R. Mohapatra

1995-01-01

322

Supported and non-supported ruthenium(II)/phosphine/[3-(2-aminoethyl)aminopropyl]trimethoxysilane complexes and their activities in the chemoselective hydrogenation of trans-4-phenyl-3-butene-2-al.  

PubMed

Syntheses of four new ruthenium(II) complexes of the [RuCl(2)(P)(2)(N)(2)] type using 2-(diphenylphosphino)ethyl methyl ether (P-O) as ether-phosphine and triphenylphosphine (PPh(3)) as monodentate phosphine ligands in the presence of [3-(2-aminoethyl)aminopropyl]trimethoxysilane as diamine co-ligand are presented for the first time. The reactions were conducted at room temperature and under an inert atmosphere. Due to the presence of the trimethoxysilane group in the backbone of complexes 1 and 2 they were subjected to an immobilization process using the sol-gel technique in the presence of tetraethoxysilane as cross-linker. The structural behavior of the phosphine ligands in the desired complexes during synthesis were monitored by (31)P{(1)H}-NMR. Desired complexes were deduced from elemental analyses, Infrared, FAB-MS and (1)H-, (13)C- and (31)P-NMR spectroscopy, xerogels X1 and X2 were subjected to solid state, (13)C-, (29)Si- and (31)P-NMR spectroscopy, Infrared and EXAF. These complexes served as hydrogenation catalysts in homogenous and heterogeneous phases, and chemoselective hydrogenation of the carbonyl function group in trans-4-phenyl-3-butene-2-al was successfully carried out under mild basic conditions. PMID:20657383

Warad, Ismail

2010-06-30

323

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

PubMed

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

Xu, Hui; Yin, Kun; Huang, Wei

2008-08-25

324

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

PubMed

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

Drahoš, Bohuslav; Pniok, Miroslav; Havlí?ková, Jana; Kotek, Jan; Císa?ová, Ivana; Hermann, Petr; Lukeš, Ivan; Tóth, Eva

2011-09-02

325

Extraction of Fe(III) by dialkyl(diaryl)-(diethylcarbamoylmethyl)phosphine oxides from HNO{sub 3} and HClO{sub 4} solutions  

SciTech Connect

An important problem of modern radiochemistry is to remove transplutonium elements (TPEs) from high-level wastes generated by the reprocessing of spent nuclear fuel and to separate them from accompanying elements, including corrosion products of the equipment, for example, Fe. The extraction of Fe(III) from HNO{sub 3} and HClO{sub 4} solutions by dibutyl- and diphenyl(diethylcarbamoylmethyl)phosphines was studied as a function of the concentration of the reagents and acids and the phase-contact time as part of an investigation of the extraction of transplutonium and accompanying elements from acidic solutions. The extraction equilibrium is quickly established in HNO{sub 3} systems; slowly, in HClO{sub 4} systems. It was found that Fe(III) is much more effectively extracted by both reagents from HClO{sub 4} solutions than from HNO{sub 3} solutions. The anomalous aryl strengthening (AAS) effect was not directly observed in these systems. Adding small quantities of HClO{sub 4} to HNO{sub 3} solutions of Fe(III) significantly increases the effectiveness of the Fe(III) extraction. The results are compared with the extraction behavior of Am under analogous conditions. The apparent solvate number during Fe(III) extraction from HClO{sub 4} increases with time from 1 to the equilibrium value (up to 3).

Litvina, M.N.; Chmutova, M.K.; Nesterova, N.P. [and others

1994-07-01

326

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

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

Ren, Yonglin; Mahon, Daphne

2007-01-10

327

Extraction of phenol from aqueous solutions by means of supported liquid membrane (MLS) containing tri-n-octyl phosphine oxide (TOPO).  

PubMed

This paper deals with the liquid-liquid extraction and the facilitated transport through a supported liquid membrane (SLM) system of aqueous phenol using tri-n-octyl phosphine oxide (TOPO) dissolved in an appropriate organic solvent. Phenol has been quantitatively extracted from aqueous acidic solutions using TOPO dissolved in kerosene as organic phase. The effect of TOPO concentration dissolved in kerosene on the extraction efficiency reveals that TOPO combined with phenol in the ratio of 1:1. Using a flat-sheet SLM (FSSLM) system, more than 65% of the initial phenol content in the feed phase was extracted and stripped in a NaOH aqueous receiving phase. The important operational variables affecting the facilitated transport of phenol through the FSSLM system studied are concentration of TOPO, membrane viscosity, feed phase pH, initial phenol concentration, polymeric support type and membrane stability. Regardless of its comparatively low extraction efficiency of phenol, the SLM based on TOPO exhibits higher long-term stability as compared to tributyl phosphate (TBP). Elaborated SLM system retained its stability and initial performance during the 5 days long experiment contrary to the TBP-SLM system where a time dependent negative tendency (transport efficiency decline) was observed. PMID:21871728

Zidi, Chiraz; Tayeb, Rafik; Dhahbi, Mahmoud

2011-08-05

328

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.  

PubMed

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 of the compound, and accurate quantification of both ascorbic acid and total ascorbic acid. In this paper, the recently introduced reductant tris[2-carboxyethyl]phosphine (TCEP) is evaluated as a reliable alternative to the commonly used reducing agent dithiothreitol (DTT). The results show that TCEP offers a more efficient reduction of dehydroascorbic acid at low pH compared to that of DTT. Moreover, while DTT maintains a reducing sample environment for less than 24 h, TCEP show complete protection from oxidation of ascorbic acid for at least 96 h following sample preparation. Removal of TCEP prior to analysis is unnecessary. A revised HPLC-EC method incorporating TCEP as reductant as well as the coanalysis of isoascorbic acid and uric acid is presented. The within- and between-day coefficients of variation for the complete assay are less than 1.5 and 3.5% for all analytes. As a whole, the method presented here is simpler and more reliable than existing methods. PMID:10860503

Lykkesfeldt, J

2000-06-15

329

Assembly of collagen fibril meshes using gold nanoparticles functionalized with tris(hydroxymethyl)phosphine-alanine as multivalent cross-linking agents.  

PubMed

We report on the use of tris(hydroxymethyl)phosphine-alanine (THPAL) functionalized gold nanoparticles as a multivalent cross-linking agent to assemble collagen fibrils into a mesh-like structure. Atomic force microscopy (AFM) was used for characterization of the structure after adsorption onto an atomically flat mica substrate, revealing a mesh-like construct in which the collagen fibrils and the gold nanoparticles interact to form interconnected nodes measuring from 100 to 500 nm. As expected, the density of the collagen mesh can be increased with a higher initial concentration of gold nanoparticles. The maximum thickness of the meshes (? 20 nm) obtained through cross-sectional height measurements confirms that the adsorbed structure consists of a single layer of collagen fibrils/gold nanoparticles assembled in two-dimensions. We propose that the capability of gold nanoparticles functionalized with the THPAL to bind to several collagen fibrils combined with the large persistence length of the fibrils, which was reported to be in the hundreds of nanometer range, are determinant factors for the preferential 2D growth of the mesh in solution. PMID:21504026

Graham, John S; Miron, Yannick; Grandbois, Michel

330

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

PubMed

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

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

2010-10-31

331

Kinetics and substitution mechanism in the reaction of the seven-coordinate complexes bis-?-diphenylphosphido- and bis-?-dimethylphosphido-octacarbonyldimolybdenum (Mo?Mo) with tri-n-butyl-phosphine  

Microsoft Academic Search

The dinuclear phosphido-bridged molybdenum complexes [(CO)4Mo(?-PR2)2Mo(CO)4] (R=Ph or Me) react with P(n-Bu)3 to give the corresponding mono and bis-phosphine derivatives. A kinetic study of the first substitution in decalin indicates a CO-dissociative mechanism involving the coordinatively unsaturated intermediate [(CO4)Mo(?-PR2)2Mo(CO)3]. The overall substitution rate depends on the rate of CO dissociation, k1, and on the rate of bimolecular attack by CO,

Marino Basato

2001-01-01

332

Electrochemical studies of the bis (triphenyl phosphine) ruthenium(II) complex, cis -[RuCl2(L)(PPh3)2], with L = 2-(2?-pyridyl)quinoxaline  

Microsoft Academic Search

Electrochemical studies of the newly synthesized bis(triphenyl phosphine) ruthenium(II) complex, cis-[RuCl2(L)(PPh3)2] (1, with L = 2-(2?-pyridyl)quinoxaline, C13N3H9), were performed in acetonitrile (ACN). For this purpose, cyclic voltammograms (CVs) as well as electrochemical impedance spectra (EIS) were recorded on either glassy carbon (GC), platinum (Pt), gold (Au), or multi-walled carbon nanotube (MWCNT) electrodes. Qualitative examination of solutions of 1 in ACN

Nikos G. Tsierkezos; Uwe Ritter; Athanassios I. Philippopoulos; Detlef Schröder

2010-01-01

333

Identification and Characterization of Mechanism of Action of P61-E7, a Novel Phosphine Catalysis-Based Inhibitor of Geranylgeranyltransferase-I  

PubMed Central

Small molecule inhibitors of protein geranylgeranyltransferase-I (GGTase-I) provide a promising type of anticancer drugs. Here, we first report the identification of a novel tetrahydropyridine scaffold compound, P61-E7, and define effects of this compound on pancreatic cancer cells. P61-E7 was identified from a library of allenoate-derived compounds made through phosphine-catalyzed annulation reactions. P61-E7 inhibits protein geranylgeranylation and blocks membrane association of geranylgeranylated proteins. P61-E7 is effective at inhibiting both cell proliferation and cell cycle progression, and it induces high p21CIP1/WAF1 level in human cancer cells. P61-E7 also increases p27Kip1 protein level and inhibits phosphorylation of p27Kip1 on Thr187. We also report that P61-E7 treatment of Panc-1 cells causes cell rounding, disrupts actin cytoskeleton organization, abolishes focal adhesion assembly and inhibits anchorage independent growth. Because the cellular effects observed pointed to the involvement of RhoA, a geranylgeranylated small GTPase protein shown to influence a number of cellular processes including actin stress fiber organization, cell adhesion and cell proliferation, we have evaluated the significance of the inhibition of RhoA geranylgeranylation on the cellular effects of inhibitors of GGTase-I (GGTIs). Stable expression of farnesylated RhoA mutant (RhoA-F) results in partial resistance to the anti-proliferative effect of P61-E7 and prevents induction of p21CIP1/WAF1 and p27Kip1 by P61-E7 in Panc-1 cells. Moreover, stable expression of RhoA-F rescues Panc-1 cells from cell rounding and inhibition of focal adhesion formation caused by P61-E7. Taken together, these findings suggest that P61-E7 is a promising GGTI compound and that RhoA is an important target of P61-E7 in Panc-1 pancreatic cancer cells.

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

2011-01-01

334

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

PubMed Central

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

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

2013-01-01

335

Phosphine-Free Synthesis from 1D Pb(OH)Cl Nanowires to 0D and 1D PbSe Nanocrystals.  

PubMed

In this paper, we report a new phosphine-free, low-cost, low-temperature colloidal method of controlled synthesis of PbSe nanocrystals in both zero-dimension (0D) and one-dimension (1D). Different from the widely used "hot injection" method and "nonprecursor injection" method, the novelty of this new method is that it does not require a nucleation process. Instead, high-quality presynthesized 1D Pb(OH)Cl nanowires (?80 to ?160 nm in diameter) can be directly used as a Pb precursor and reacted with a Se precursor to form monodisperse dot-shaped 0D cubic PbSe and 1D orthorhombic PbSe nanowires. 0D cubic PbSe nanocrystals begin to form at elevated temperatures after the Se precursor is added to react with Pb(OH)Cl nanowires. By prolonging the reaction time for 3 h, good self-assembled 0D cubic PbSe nanocrystals can be synthesized with an average diameter of about 15 nm. Furthermore, such method has been demonstrated to synthsize high-quality 1D PbSe nanowires successfully with temperature as low as 110 °C. 1D PbSe nanowires possess a mean diameter of 15-24 nm with the shortest and longest length from 600 nm to 5 ?m. The only sharp and strong peak, which is consistent with characteristic peaks of orthorhombic PbSe, indicates that the nanowires' elongation axis is in the [111] direction, and 0D cubic PbSe nanocrystals change to 1D orthorhombic PbSe nanowires completely. PMID:24066872

Shen, Huaibin; Li, Jinjie; Shang, Hangying; Niu, Jinzhong; Xu, Weiwei; Wang, Hongzhe; Guo, Fang; Li, Lin Song

2013-10-10

336

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

PubMed

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

García-Álvarez, Joaquín; Díez, Josefina; Gimeno, José; Seifried, Christine M; Vidal, Cristian

2013-04-17

337

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

PubMed Central

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

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

2010-01-01

338

Binuclear iron-sulfur complexes with bidentate phosphine ligands as active site models of Fe-hydrogenase and their catalytic proton reduction.  

PubMed

The displacement of CO in a few simple Fe(I)-Fe(I) hydrogenase model complexes by bisphosphine ligands Ph2P-(CH2)n-PPh2 [with n = 1 (dppm) or n = 2 (dppe)] is described. The reaction of [{mu-(SCH2)2CH2}Fe2(CO)6] (1) and [{mu-(SCH2)2N(CH2CH2CH3)}Fe2(CO)6] (2) with dppe gave double butterfly complexes [{mu-(SCH2)2CH2}Fe2(CO)5(Ph2PCH2)]2 (3) and [{mu-(SCH2)2N(CH2CH2CH3)}Fe2(CO)5(Ph2PCH2)]2 (4), where two Fe2S2 units are linked by the bisphosphine. In addition, an unexpected byproduct, [{mu-(SCH2)2N(CH2CH2CH3)}Fe2(CO)5{Ph2PCH2CH2(Ph2PS)}] (5), was isolated when 2 was used as a substrate, where only one phosphorus atom of dppe is coordinated, while the other has been converted to P=S, presumably by nucleophilic attack on bridging sulfur. By contrast, the reaction of 1 and 2 with dppm under mild conditions gave only complexes [{mu-(SCH2)2CH2}Fe2(CO)5(Ph2PCH2PPh2)] (6) and [{mu-(SCH2)2N(CH2CH2CH3)}Fe2(CO)5(Ph2PCH2PPh2)] (8), where one ligand coordinated in a monodentate fashion to one Fe2S2 unit. Furthermore, under forcing conditions, the complexes [{mu-(SCH2)2CH2}Fe2(CO)4{mu-(Ph2P)2CH2}] (7) and [{mu-(SCH2)2N(CH2CH2CH3)}Fe2(CO)4{mu-(Ph2P)2CH2}] (9) were formed, where the phosphine acts as a bidentate ligand, binding to both the iron atoms in the same molecular unit. Electrochemical studies show that the complexes 3, 4, and 9 catalyze the reduction of protons to molecular hydrogen, with 4 electrolyzed already at -1.40 V versus Ag/AgNO3 (-1.0 V vs NHE). PMID:17295467

Gao, Weiming; Ekström, Jesper; Liu, Jianhui; Chen, Changneng; Eriksson, Lars; Weng, Linhong; Akermark, Björn; Sun, Licheng

2007-02-13

339

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

PubMed

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

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

2011-10-18

340

New rac-XP(O)(OC6H5)(NHC6H4-p-CH3) [X = N(CH3)(cyclo-C6H11) and NH(C3H5)] and rac-(C6H5CH2NH)P(O)(OC6H5)(NH-cyclo-C6H11) mixed-amide phosphinates.  

PubMed

The mixed-amide phosphinates, rac-phenyl (N-methylcyclohexylamido)(p-tolylamido)phosphinate, C20H27N2O2P, (I), and rac-phenyl (allylamido)(p-tolylamido)phosphinate, C16H19N2O2P, (II), were synthesized from the racemic phosphorus-chlorine compound (R,S)-(Cl)P(O)(OC6H5)(NHC6H4-p-CH3). Furthermore, the phosphorus-chlorine compound ClP(O)(OC6H5)(NH-cyclo-C6H11) was synthesized for the first time and used for the synthesis of rac-phenyl (benzylamido)(cyclohexylamido)phosphinate, C19H25N2O2P, (III). The strategies for the synthesis of racemic mixed-amide phosphinates are discussed. The P atom in each compound is in a distorted tetrahedral (N(1))P(=O)(O)(N(2)) environment. In (I) and (II), the p-tolylamido substituent makes a longer P-N bond than those involving the N-methylcyclohexylamido and allylamido substituents. In (III), the differences between the P-N bond lengths involving the cyclohexylamido and benzylamido substituents are not significant. In all three structures, the phosphoryl O atom takes part with the N-H unit in hydrogen-bonding interactions, viz. an N-H...O=P hydrogen bond for (I) and (N-H)(N-H)...O=P hydrogen bonds for (II) and (III), building linear arrangements along [001] for (I) and along [010] for (III), and a ladder arrangement along [100] for (II). PMID:24096512

Pourayoubi, Mehrdad; Karimi Ahmadabad, Fatemeh; Eshtiagh-Hosseini, Hossein; Ku?eráková, Monika; Eigner, Václav; Dušek, Michal

2013-09-06

341

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

SciTech Connect

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

Chauvin, Y.; Einloft, S.; Olivier, H. [Inst. Francais du Petrole, Rueil-Malmaison (France)

1995-04-01

342

Highly improved electroluminescence from a series of novel Eu(III) complexes with functional single-coordinate phosphine oxide ligands: tuning the intramolecular energy transfer, morphology, and carrier injection ability of the complexes.  

PubMed

The functional single-coordinate phosphine oxide ligands (4-diphenylaminophenyl)diphenylphosphine oxide (TAPO), (4-naphthalen-1-yl-phenylaminophenyl)diphenylphosphine oxide (NaDAPO), and 9-[4-(diphenylphosphinoyl)phenyl]-9H-carbazole (CPPO), as the direct combinations of hole-transporting moieties, and electron-transporting triphenylphosphine oxide (TPPO) were designed and synthesized (amines or carbazole), together with their Eu(III) complexes [Eu(tapo)(2)(tta)(3)] (1), [Eu(nadapo)(2)(tta)(3)] (2), and [Eu(cppo)(2)(tta)(3)] (3; TTA: 2-thenoyltrifluoroacetonate). The investigation indicated that by taking advantage of the modification inertia of the phosphine oxide ligands, the direct introduction of the hole-transport groups as chromophore made TAPO, NaDAPO, and CPPO obtain the most compact structure and mezzo S(1) and T(1) energy levels, which improved the intramolecular energy transfer in their Eu(III) complexes. The amorphous phase of 1-3 proved the weak intermolecular interaction, which resulted in extraordinarily low self-quenching of the complexes. The excellent double-carrier transport ability of the ligands was studied with Gaussian calculations, and the bipolar structure of TAPO and CPPO was proved. The great improvement of the double-carrier transport ability of 1-3 was shown by cyclic voltammetry. Their HOMO and LUMO energy levels of around 5.3 and 3.0 eV, respectively, are the best results for Eu(III) complexes reported so far. A single-layer organic light-emitting diode of 2 had the impressive brightness of 59 cd m(-2) which, to the best of our knowledge, is the highest reported so far. Both of the four-layer devices based on pure 1 and 2 had a maximum brightness of more than 1000 cd m(-2), turn-on voltages lower than 5 V, maximum external quantum yields of more than 3 % and excellent spectral stability. PMID:17918175

Xu, Hui; Yin, Kun; Huang, Wei

2007-01-01

343

Pincer phosphine complexes of ruthenium: formation of Ru(P-O-P)(PPh3)HCl (P-O-P = xantphos, DPEphos, (Ph2PCH2CH2)2O) and Ru(dppf)(PPh3)HCl and characterization of cationic dioxygen, dihydrogen, dinitrogen, and arene coordinated phosphine products.  

PubMed

Treatment of Ru(PPh(3))(3)HCl with the pincer phosphines 9,9-dimethyl-4,5-bis(diphenylphosphino)xanthene (xantphos), bis(2-diphenylphosphinophenyl)ether (DPEphos), or (Ph(2)PCH(2)CH(2))(2)O affords Ru(P-O-P)(PPh(3))HCl (xantphos, 1a; DPEphos, 1b; (Ph(2)PCH(2)CH(2))(2)O, 1c). The X-ray crystal structures of 1a-c show that all three P-O-P ligands coordinate in a tridentate manner through phosphorus and oxygen. Abstraction of the chloride ligand from 1a-c by NaBAr(4)(F) (BAr(4)(F) = B(3,5-C(6)H(3)(CF(3))(2))(4)) gives the cationic aqua complexes [Ru(P-O-P)(PPh(3))(H(2)O)H]BAr(4)(F) (3a-c). Removal of chloride from 1a by AgOTf yields Ru(xantphos)(PPh(3))H(OTf) (2a), which reacts with water to form [Ru(xantphos)(PPh(3))(H(2)O)H](OTf). The aqua complexes 3a-b react with O(2) to generate [Ru(xantphos)(PPh(3))(eta(2)-O(2))H]BAr(4)(F) (5a) and [Ru(DPEphos)(PPh(3))(eta(2)-O(2))H]BAr(4)(F) (5b). Addition of H(2) or N(2) to 3a-c yields the thermally unstable dihydrogen and dinitrogen species [Ru(P-O-P)(PPh(3))(eta(2)-H(2))H]BAr(4)(F) (6a-c) and [Ru(P-O-P)(PPh(3))(N(2))H]BAr(4)(F) (7a-c), which have been characterized by multinuclear NMR spectroscopy at low temperature. Ru(PPh(3))(3)HCl reacts with 1,1'-bis(diphenylphosphino)ferrocene (dppf) to give the 16-electron complex Ru(dppf)(PPh(3))HCl (1d), which upon treatment with NaBAr(4)(F), affords [Ru(dppf){(eta(6)-C(6)H(5))PPh(2)}H]BAr(4)(F) (8), in which the PPh(3) ligand binds eta(6) through one of the PPh(3) phenyl rings. Reaction of 8 with CO or PMe(3) at elevated temperatures yields the 18-electron products [Ru(dppf)(PPh(3))(CO)(2)H]BAr(F)(4) (9) and [Ru(PMe(3))(5)H]BAr(4)(F) (10). PMID:20575584

Ledger, Araminta E W; Moreno, Aitor; Ellul, Charles E; Mahon, Mary F; Pregosin, Paul S; Whittlesey, Michael K; Williams, Jonathan M J

2010-08-16

344

Diphenyl(1-naphthyl)phosphine ancillary for assembling of red and orange-emitting Ir(III) based phosphors; strategic synthesis, photophysics, and organic light-emitting diode fabrication.  

PubMed

Treatment of a series of dinuclear Ir(III) complexes [(fnazo)(2)Ir(?-Cl](2), [(fpiq)(2)Ir(?-Cl](2), and [(fppy)(2)Ir(?-Cl](2) with diphenyl(1-naphthyl)phosphine (dpnH) in decalin at 100 °C afforded the simple adducts, trans-N,N'-[(fnazo)(2)Ir(dpnH)Cl] (1a), trans-N,N'-[(fpiq)(2)Ir(dpnH)Cl] (1b), and trans-N,N'-[(fppy)(2)Ir(dpnH)Cl] (1c), for which the C(?)N cyclometalating reagents, that is, fnazoH, fpiqH and fppyH, stands for 4-(4-fluorophenyl)quinazoline, 1-(4-fluorophenyl)isoquinoline and 4-fluorophenylpyridine, respectively. Single crystal X-ray diffraction study on 1a revealed existence of two trans-N,N' cyclometalates, with both chloride and dpnH donors located at the positions opposite to the phenyl substituents. Subsequent heating of 1a-1c at higher temperature afforded the second isomer (2a-2c), showing formation of cis-N,N' orientation for the aforementioned cyclometalates. Further thermolysis of either trans or cis-Ir(III) complexes 1 or 2 in presence of sodium acetate, which serves as both activator and chloride scavenger, gave successful isolation of a mixture of two fully cyclometalated Ir(III) complexes trans-N,N'-[(C(?)N)(2)Ir(dpn)] (3a-3c) and cis-N,N'-[(C(?)N)(2)Ir(dpn)] (4a-4c). Structural and photophysical properties of complexes 3a-3c and 4a-4c were measured and compared. Time-dependent density functional theory (DFT) studies suggested that, upon changing the C(?)N cyclometalates from quinazolinyl, isoquinolinyl, and, finally, to pyridyl fragment, the lowest unoccupied molecular orbitals (LUMOs) are gradually shifted from the cyclometalating nitrogen heterocycles to the 1-naphthyl group of the phosphine chelate and, concomitantly altered the photophysical properties. An organic light-emitting diode (OLED) using orange-red phosphors 4a and 4b has been successfully fabricated. At the practical brightness of 500 cd·m(-2), decent external quantum efficiency of 10.6% and 12.5% could be reached for 4a and 4b, respectively, revealing the usefulness of relevant molecular architecture in designing triplet OLED emitters. PMID:20815333

Du, Bo-Sian; Lin, Chen-Huey; Chi, Yun; Hung, Jui-Yi; Chung, Min-Wen; Lin, Tsung-Yi; Lee, Gene-Hsiang; Wong, Ken-Tsung; Chou, Pi-Tai; Hung, Wen-Yi; Chiu, Hao-Chih

2010-10-01

345

Aqueous Solution Chemistry of the Mo(3)PdS(4) Cube: Substitution Reactions and the Double to Single Cube Interconversion Induced by CO, Two Phosphines, Cl(-), Br(-), and NCS(-).  

PubMed

The kinetics of conversion of an edge-linked double cube, in this case [{Mo(3)PdS(4)(H(2)O)(9)}(2)](8+), to the corresponding single cube [Mo(3)(PdX)S(4)(H(2)O)(9)](4+), has been studied for the first time. Reaction is induced by six reagents X = CO, two water-soluble phosphines, Cl(-), Br(-), and NCS(-), which complex at the tetrahedral Pd. The first stage of reaction is fast and is accompanied by color changes, e.g. purple to dark blue in the case of Cl(-), assigned as double to single cube conversion. With X = CO and the two phosphines, when absorbance changes are intense enough for stopped-flow monitoring with reactants at Pd-SCN. On removal of e.g. Cl(-) by chromatography or addition of Ag(+), the double cube re-forms. PMID:11666742

Saysell, David M.; Lamprecht, Gert J.; Darkwa, James; Sykes, A. Geoffrey

1996-09-11

346

Solvents for bulk removal of organics from coal-conversion condensate waters. [Methyl isobutyl ketone, diisopropyl ether and mixture of 25% w/w trioctyl phosphine oxide in diisobutyl ketone  

SciTech Connect

In this work chemical analyses and experimental tests of extraction solvents are discussed for condensate waters from a coal gasification plant. The results of the study showed that methyl isobutyl ketone (MIBK) provides much higher distribution coefficients than diisopropyl ether DIPE for phenol and dihydroxybenzenes. About 90% of the chemical oxygen demand (COD) from one condensate water sample had a sufficiently high K/sub D/ into MIBK that it could be removed by this solvent in a counter-current extraction process at an economically reasonable solvent-to-water ratio. TOPO (mixture of 25% w/w trioctyl phosphine oxide in diisobutyl ketone) in a suitable diluent has high equilibrium distribution coefficients for phenols and dihydroxybenzenes, and therefore has the potential to remove these compounds at lower solvent-to-water ratios. However, this solvent may be difficult to regenerate in a continuous condensate-water extraction process. Analytical techniques are discussed that provide higher recoveries for phenols and dihydroxybenzenes as compared to the standard MC/GC-MS technique. Hydantoins have been identified in four condensate water samples. About 20 to 30% of the COD remains unidentified in these four condensate water samples. Some of these unidentified compounds have very low values of K/sub D/ for extraction into MIBK. More information is required about these unidentified solutes before reliable solvent extraction processes can be designed. 6 tables.

Mohr, D.H.; King, C.J.

1983-03-01

347

Determination of SQ 33,600, a phosphinic acid containing HMG CoA reductase inhibitor, in human serum by high-performance liquid chromatography combined with ionspray mass spectrometry.  

PubMed

A method for the determination of SQ 33,600 in human serum is presented. This compound, which contains both carboxylic and phosphinic acid functional groups, is an HMG CoA reductase inhibitor currently under clinical investigation at the Bristol-Myers Squibb Pharmaceutical Research Institute. Human serum extracts prepared using solid-phase techniques were analyzed by combining high-performance liquid chromatography and atmospheric pressure ionization mass spectrometry. Under the conditions of the analysis, SQ 33,600 and its fluorinated analog, SQ 33,547, used as the internal standard, existed as anions in solution and could be sampled directly using the ionspray technique. The method utilized a simple isocratic mobile-phase system. No sample derivatization was required for these polar molecules. The retention time of the analytes was 3.5 min with a total analysis time of 5 min. The limit of detection was 0.5 ng ml-1 serum with a minimum quantifiable limit of 2.0 ng ml-1. The method was linear to at least 400 ng ml-1. PMID:1567915

Wang-Iverson, D; Arnold, M E; Jemal, M; Cohen, A I

1992-04-01

348

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

PubMed

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

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

2008-10-08

349

Application of 4,4,4-Trifluoro-1-(Biphenyl-4-yl)Butane-1,3-Dione as a Chelating Extractant in the Solvent Extraction and Separation of Light Lanthanoids in Combination with Phosphine Oxides.  

PubMed

The 4,4,4-trifluoro-1-(biphenyl-4-yl)butane-1,3-dione(HL) has been synthesized and its complexation properties in solution was examined. Mixed ligand chelate extraction of light trivalent lanthanoids (La÷Gd) from chloride medium at constant ionic strength µ = 0.1 into C6H6 with HL in combination with one of the three phosphine oxide compounds trioctylphosphine oxide(TOPO), tributylphosphine oxide(TBPO) or triphenyphosphine oxide(TPPO) was studied. The composition of the extracted species was established as LnL3 with HL alone and as LnL3 2S in the presence of TOPO and TBPO or LnL3 S with the mixture of HL-TPPO. The 28 values of the overall equilibrium constants were calculated. A synergic effect up to 103-104 was observed for the extraction of the above-mentioned lanthanoid ions with binary mixtures of extractants. The change of the synergistic agent causes a significant increase of the KL,S values in the order TBPO < TPPO < TOPO. The parameters of the extraction process were determined and the separation factors between two adjacent Ln(III) were calculated. PMID:24061883

Atanassova, Maria; Kaloyanova, Stefka; Deligeorgiev, Todor

2010-12-01

350

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  

Microsoft Academic Search

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

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

2011-01-01

351

Chelating or bridging Pd(II) and Pt(II) metalloligands from the functional phosphine ligand N-(diphenylphosphino)-1,3,4-thiadiazol-2-amine. New heterometallic Pd(II)/Pt(II) and Pt(II)/Au(I) complexes.  

PubMed

The reaction of two equivalents of the functional phosphine ligand N-(diphenylphosphino)-1,3,4-thiadiazol-2-amine Ph2PNHC=NNCHS (2) with [PdCl2(NCPh)2] in the presence of NEt3 gives the neutral, P,N-chelated complex cis-[Pd(Ph2PN=CNN=CHS)2] ([Pd(2-H)2], 3b), which is analogous to the Pt(II) analogue cis-[Pt (Ph2PN=CNN=CHS)2] ([Pt(2-H)2], 3a) reported previously. These complexes function as chelating metalloligands when further coordinated to a metal through each of the CH-N atoms. In the resulting complexes, each endo-cyclic N donor of the thiadiazole rings is bonded to a different metal centre. Thus, the heterodinuclear palladium/platinum complexes cis-[Pt(Ph2PN=CNN=CHS)2PdCl2]([Pt(2-H)2·PdCl2], 4a) and cis-[Pd(Ph2PN=CNN=CHS)2PtCl2]([Pd(2-H)2·PtCl2], 4b) were obtained by reaction with [PdCl2(NCPh)2] and [PtCl2(NCPh)2], respectively. In contrast, reaction of 3a with [AuCl(tht)] occurred instead at the P-bound N atom, and afforded the platinum/digold complex cis-[Pt{Ph2PN(AuCl)=CNN=CHS}2] ([Pt(2-H)2(AuCl)2], 5). For comparison, reaction of 4a with HBF4 yielded cis-[Pt(Ph2PNH=CNN=CHS)2PdCl2](BF4)2([H24a](BF4)2, 6), in which the chelated PdCl2 moiety is retained. Complexes 3b, 4a·CH2Cl2, 4b·0.5C7H8, 5·4CHCl3 and 6 have been structurally characterized by X-ray diffraction. PMID:21505707

Zhang, Shuanming; Pattacini, Roberto; Braunstein, Pierre

2011-04-20

352

Synthesis and properties of novel flame-retardant and thermally stable poly(amideimide) s from N,N? -(bicyclo[2,2,2]oct-7-ene-tetracarboxylic)-bis-L-amino acids and phosphine oxide moiety by two different methods  

Microsoft Academic Search

N,N?-(bicyclo[2,2,2]oct-7-ene-tetracarboxylic)-bis-L-amino acids3a-g were synthesized by the condensation reaction of bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride1 with two equimolars of Lalanine2a, L-valine2b, L-leucine2c, L-isoleucine2d, L-phenyl alanine2e, L-2-aminobutyric acid2f and L-histidine2g in an acetic acid solution. Seven new poly(amide-imide)s PAIs5a-g were synthesized through the direct polycondensation reaction of seven chiralN,N?-(bicyclo[2,2,2]oct-7-ene-tetracarboxylic)-bis-L-amino acids3a-g with bis(3-amino phenyl) phenyl phosphine oxide4 by two different methods: direct polycondensation in a medium

Khalil Faghihi; Mohsen Hajibeygi; Meisam Shabanian

2009-01-01

353

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

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.

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

354

Phosphine photochemistry in the atmosphere of Saturn  

NASA Astrophysics Data System (ADS)

The photochemistry of PH3 in the atmosphere of Saturn is studied, including the effects of coupling with the photochemistries of NH3 and hydrocarbons. The vertical concentration of PH3 is found to be extremely sensitive to the eddy diffusion coefficient (K) profile used. If K is roughly 10,000 sq cm/sec in the upper troposphere, PH3 should be depleted there with a scale height of about 3.5 km. An upper limit of 100,000 sq cm/sec is estimated for K. If the gas phase concentration of P2H4 can be neglected, production of molecular phophorus is very unlikely unless the spin-forbidden recombination reaction PH+H2+M - PH3+M occurs with an exceptionally low rate. Coupling of PH3 and hydrocarbon photochemistries is very important. Possible observable amounts of the organophosphorus molecules CH3PH2 and HCP are tentatively predicted.

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

1984-09-01

355

(4-Ethenylphen-yl)diphenyl-phosphine selenide  

PubMed Central

In the title mol­ecule, C10H17PSe, the P atom has a distorted tetra­hedral environment resulting in an effective cone angle of 165°. The benzene ring makes dihedral angles of 70.04?(8) and 77.28?(8)° with the phenyl rings, while the dihedral angle between the phenyl rings is 62.95?(8)°. In the crystal, mol­ecules are linked by C—H?? inter­actions.

Phasha, Zanele H.; Makhoba, Sizwe; Muller, Alfred

2012-01-01

356

40 CFR 721.6020 - Phosphine, dialkylyphenyl.  

Code of Federal Regulations, 2013 CFR

...and availability of MSDSs does not apply when an MSDS is not required under § 721.72(c). The provision...requiring placement of specific information in an MSDS does not apply when an MSDS is not required under § 721.72(c)....

2013-07-01

357

Observations on Some Poly(metal phosphinates).  

National Technical Information Service (NTIS)

Dioctylphosphinates of the bivalent first-transition-series elements from chromium through zinc have been prepared and characterized. The variety of forms found is discussed. Cobalt(II), iron(II), and manganese(II) yield a form based on octahedral centers...

B. P. Block H. D. Gillman P. Nannelli P. T. Grzymala

1972-01-01

358

Meth-yl(phen-yl)phosphinic acid.  

PubMed

The crystal structure of the title compound, C(7)H(9)O(2)P, displays O-H?O hydrogen bonding , which links individual mol-ecules related via the c-glide plane and translational symmetry along the crystallographic b-axis direction into continuous chains. PMID:22091039

Burrow, Robert A; Siqueira da Silva, Rubia M

2011-07-09

359

Benz-yl(phen-yl)phosphinic acid.  

PubMed

The title compound, C(13)H(13)O(2)P, crystallized as enanti-omerically pure crystals; for the crystal measured, the P atom has R stereochemistry. The crystal structure displays O-H?O hydrogen bonding, which links individual mol-ecules related by a 2(1) screw axis parallel to the crystallographic a-axis direction into continuous chains. PMID:21754372

Burrow, Robert A; Siqueira da Silva, Rubia M

2011-04-07

360

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

PubMed Central

The title compound, [Co(CN)(C3H9P)4], was obtained as a product of the reaction of [Co(PMe3)4] with a molar equivalent of 2,6-difluoro­benzonitrile in diethyl ether. This compound is stable in the air for several hours, but rapidly decomposes at room temperature in solution. The cobalt(I) atom has s trigonal–bipyramidal coordination enviroment in which the cyano group and one of the PMe3 groups are in the axial positions.

Xu, Xiaofeng; Feng, Lei; Li, Xiaoyan

2011-01-01

361

Molybdenum(IV) Cyclopentadienyl Phosphine Halide Complexes.  

National Technical Information Service (NTIS)

Slow addition of a solution of CpMo(CO)3Cl (Cp = eta5-C5H5) to Ph2PCH2CH2PPh2 (dppe) in bioling toluene gives CpMo(dppe) (CO)Cl (2) as red crystals in 85% yield. Oxidation of 2 with Cl2 or Br2 at 0 C results in the formation of the formally eight-coordina...

K. Starker M. D. Curtis

1985-01-01

362

(Carbonyl-1?C)bis-[2,3(?5)-cyclo-penta-dien-yl][?3-(S-methyl trithio-carbonato)methylidyne-1:2:3?4 C,S??:C:C](triphenyl-phosphine-1?P)(?3-sulfido-1:2:3?3 S)dicobalt(II)iron(II) trifluoro-methane-sulfonate  

PubMed Central

The asymmetric unit of the title compound, [FeCo2(C5H5)2(C3H3S3)S(C18H15P)(CO)]CF3SO3, consists of a triangular irondicobalt cluster cation and a trifluoro­methane­sulfonate anion. In the cation, the FeCo2 triangle is symmetrically capped on one face by an S atom and on the other by a C atom linked to a methyl trithio­carbonate residue that bridges the Fe—C bond. Each Co atom carries a cyclo­penta­dienyl ligand while the Fe atom coordinates to one carbonyl and one triphenyl­phosphine ligand. In the crystal structure, the cation is linked to the anion by a number of weak non-classical C—H?O and C—H?F hydrogen bonds and weak S?O (3.317?Å) and S?F (3.198?Å) inter­actions. The structure is further stabilized by additional inter­molecular C—H?O, C—H?F and O?O (2.942?Å) contacts, together with an unusual S??(Cp) inter­action (S?centroid distance = 3.385?Å), generating an extended network.

Manning, Anthony R.; McAdam, C. John; Palmer, Anthony J.; Simpson, Jim

2008-01-01

363

(Carbonyl-1?C)bis-[2,3(?)-cyclo-penta-dien-yl][?(3)-(S-methyl trithio-carbonato)methylidyne-1:2:3?C,S'':C:C](triphenyl-phosphine-1?P)(?(3)-sulfido-1:2:3?S)dicobalt(II)iron(II) trifluoro-methane-sulfonate.  

PubMed

The asymmetric unit of the title compound, [FeCo(2)(C(5)H(5))(2)(C(3)H(3)S(3))S(C(18)H(15)P)(CO)]CF(3)SO(3), consists of a triangular irondicobalt cluster cation and a trifluoro-methane-sulfonate anion. In the cation, the FeCo(2) triangle is symmetrically capped on one face by an S atom and on the other by a C atom linked to a methyl trithio-carbonate residue that bridges the Fe-C bond. Each Co atom carries a cyclo-penta-dienyl ligand while the Fe atom coordinates to one carbonyl and one triphenyl-phosphine ligand. In the crystal structure, the cation is linked to the anion by a number of weak non-classical C-H?O and C-H?F hydrogen bonds and weak S?O (3.317?Å) and S?F (3.198?Å) inter-actions. The structure is further stabilized by additional inter-molecular C-H?O, C-H?F and O?O (2.942?Å) contacts, together with an unusual S??(Cp) inter-action (S?centroid distance = 3.385?Å), generating an extended network. PMID:21202187

Manning, Anthony R; McAdam, C John; Palmer, Anthony J; Simpson, Jim

2008-04-10

364

Technetium electrochemistry. 4. Electrochemical and spectroelectrochemical studies on the bis(tertiary phosphine or arsine (D))rhenium(III) complexes trans-(ReD/sub 2/X/sub 2/)/sup +/ (X = Cl, Br). Comparison with the technetium(III) analogues  

SciTech Connect

The redox properties of a series of rhenium(III) complexes with the general formula trans-(ReD/sub 2/X/sub 2/)/sup +/ (where D is one of the chelating phosphine or arsine ligands 1,2-bis(dimethylphosphino)ethane, 1,2-bis(diethylphosphino)ethane, 1,2-bis(diphenylphosphino)ethane, or 1,2-bis(dimethylarsino)benzene and X is Cl or Br) were investigated in 0.5 M TEAP/DMF by cyclic voltammetry, thin-layer electrochemistry, and thin-layer spectroelectrochemistry. The cationic trans-(ReD/sub 2/X/sub 2/)/sup +/ complexes exhibit a diffusion-controlled, reversible one-electron reduction to the neutral trans-(ReD/sub 2/X/sub 2/)/sup 0/ complexes at a platinum-disk electrode. The formal reduction potential, E/sup 0/', of the Re(III/II) redox couple ranges from -0.205 to 0.450 V vs Ag/AgCl (3 M NaCl). Further reduction to the rhenium(I) anion, trans-(ReD/sub 2/X/sub 2/)/sup -/, is possible; however, the reversibility of this process depends on the nature of the coordinating ligands and the experimental conditions. The Re(II/I) redox couple occurs at an E/sup 0/' value ca. 1.11 V more negative than that of the corresponding Re(III/II) couple. Thin-layer spectroelectrochemistry has been used to study the halogen-to-metal charge-transfer (HTMCT) band(s) of the Re(III) and Re(II) complexes. 36 references, 7 figures, 3 tables.

Kirchhoff, J.R.; Heineman, W.R.; Deutsch, E.

1987-09-23

365

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

PubMed

Highly photoluminescent (PL) reverse type-I ZnSe/CdSe nanocrystals (NCs) and ZnSe/CdSe/CdS/Cd(x)Zn(1 - x)S/ZnS core/multishell NCs were successfully synthesized by a phosphine-free method. By this low-cost, 'green' synthesis route, more than 10 g of high-quality ZnSe/CdSe/CdS/Cd(x)Zn(1 - x)S/ZnS NCs were synthesized in a large scale synthesis. After the overgrowth of a CdS/Cd(x)Zn(1 - x)S/ZnS multishell on ZnSe/CdSe cores, the PL quantum yields (QYs) increased from 28% to 75% along with the stability improvement. An amphiphilic oligomer was used as a surface coating agent to conduct a phase transfer experiment, core/multishell NCs were dissolved in water by such surface modification and the QYs were still kept above 70%. The as-prepared water dispersible ZnSe/CdSe/CdS/Cd(x)Zn(1 - x)S/ZnS core/multishell NCs not only have high fluorescence QYs but also are extremely stable in various physiological conditions. Furthermore, a biosensor system (lateral flow immunoassay system, LFIA) for the detection of human hepatitis B surface antigen (HBsAg) was developed by using this water-soluble core/multishell NCs as a fluorescent label and a nitrocellulose filter membrane for lateral flow. The result showed that such ZnSe/CdSe/CdS/Cd(x)Zn(1 - x)S/ZnS core/multishell NCs were excellent fluorescent labels to detect HBsAg. The sensitivity of HBsAg detection could reach as high as 0.05 ng ml( - 1). PMID:21852741

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

2011-08-19

366

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

NASA Astrophysics Data System (ADS)

An extractive spectrophotometric analytical method has been developed for the determination of uranium in ore leach solution. This technique is based on the selective extraction of uranium from multielement system using a synergistic mixture of 2-ethylhexyl phosphonic acid-mono-2-ethylhexyl ester (PC88A) and tri-n-octyl phosphine oxide (TOPO) in cyclohexane and color development from the organic phase aliquot using 2-(5-Bromo-2-pyridylazo)-5-diethyl aminophenol (Br-PADAP) as chromogenic reagent. The absorption maximum (?max) for UO22+-Br-PADAP complex in organic phase samples, in 64% (v/v) ethanol containing buffer solution (pH 7.8) and 1,2-cyclohexylenedinitrilotetraacetic acid (CyDTA) complexing agent, has been found to be at 576 nm (molar extinction coefficient, ?: 36,750 ± 240 L mol-1 cm-1). Effects of various parameters like stability of complex, ethanol volume, ore matrix, interfering ions etc. on the determination of uranium have also been evaluated. Absorbance measurements as a function of time showed that colored complex is stable up to >24 h. Presence of increased amount of ethanol in colored solution suppresses the absorption of a standard UO22+-Br-PADAP solution. Analyses of synthetic standard as well as ore leach a solution show that for 10 determination relative standard deviation (RSD) is <2%. The accuracy of the developed method has been checked by determining uranium using standard addition method and was found to be accurate with a 98-105% recovery rate. The developed method has been applied for the analysis of a number of uranium samples generated from uranium ore leach solutions and results were compared with standard methods like inductively coupled plasma emission spectrometry (ICPAES). The determined values of uranium concentrations by these methods are within ±2%. This method can be used to determine 2.5-250 ?g mL-1 uranium in ore leach solutions with high accuracy and precision.

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

2012-06-01

367

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

NASA Astrophysics Data System (ADS)

A diverse array of structures for the complexes of silver(I) halide with triphenylphosphine (PPh3) has been studied. The complexes may be described as being of the type [AgX(PPh3)n] (X = Cl, Br or I). The value of n varies in the range of 1-3. This also indicates that the stoichiometry of the complexes is in the range of 1-3. The complex with stoichiometry 1:1 is a tetramer. There are two structural types of tetramer reported, termed cubane and step or chair. The cubane structure has been reported for [AgX(PPh3)]4 (X = Cl, Br or I), while the step structure has only been reported for [AgI(PPh3)]4. The complex with stoichiometry 1:2 may be a monomer or a dimer. The monomer has a quasi trigonal planar structural type and has only been reported for [AgBr(PPh3)2]. The dimer has been reported for [(PPh3)2Ag(?-X)2Ag(PPh3)2] (X = Cl or Br) with silver atom in the distorted tetrahedral environment. The complex with stoichiometry 1:3 has a distorted tetrahedral structural type and has been reported for [AgX(PPh3)3] (X = Cl, Br or I). Changing PPh3 with more hindered ligand such as tricyclohexylephosphine (Pcy3) or derivative of PPh3 such as diphenyl-2,4,6-trimethoxy(phenyl)phosphine (dpmp), phenyl-bis{2,4,6-trimethoxy(phenyl)} phosphine (pdmp), or tris{2,4,6-trimethoxy(phenyl)}phosphine (tmpp) may give complexes with various structural types but with lower range of stoichiometry. Synthesis and X-ray structural study of these complexes has been done with the results summarized below. Silver(I) halide and Pcy3 give complexes with stoichiometry 1:1 and 1:2. The complex with stoichiometry 1:1 is a dimer or cubane. The dimer is observed for [(Pcy3)Ag(?-X)2Ag(Pcy3)] (X = Cl or Br). The unusual dimer is observed for [(Pcy3)Ag(?-I)2(?-py)Ag(Pcy3)] where the pyridine ligand is bonded to two silver atoms. The cubane is observed for [AgI(Pcy3)]4. The complex with stoichiometry 1:2 has a quasi trigonal planar structural type and has been observed for [AgX(Pcy3)2] (X = Cl, Br, I). Silver(I) halide and dpmp give complexes with stoichiometry 1:1 and 1:2. The complex with stoichiometry 1:1 is a dimer and has been observed for [(dpmp)Ag(?-X)2Ag(dpmp)] (X = Cl, Br or I). The complex with stoichiometry 1:2 has a quasi trigonal planar structural type and has been observed for [AgX(dpmp)2] (X = Cl, Br, I). Silver(I) halide and pdmp also give complexes with stoichiometry 1:1 and 1:2. The complex with stoichiometry 1:1 is a dimer and has been observed for [(pdmp)Ag(?-X)2Ag(pdmp)] (X = Cl, Br or I). The complex with stoichiometry 1:2 has a quasi trigonal planar structural type and has been observed for [AgX(pdmp)2] (X = Cl, Br, I). Silver(I) halide and tmmp only give complexes with stoichiometry 1:1. This complex is a monomer and has been observed for [AgX(tmpp)] (X = Cl or Br). In this complex the silver atom is in a quasi linear environment. Based on the bond lengths between silver and phosphorous atoms in the complexes obtained, it can be concluded that bulky ligands tend to give complexes with lower range of stoichiometry. In addition, the bulkier the ligand the longer the bond length between the silver and phosphorous atoms.

Effendy; White, A. H.

2008-03-01

368

Antibacterial activity of rhodium, iridium, and ruthenium tripodal phosphine complexes.  

PubMed

Twenty-eight rhodium, iridium, or ruthenium complexes were evaluated for their in vitro antibacterial activity against Enterococcus faecalis ATCC 29212, Staphylococcus aureus ATCC 29213, Escherichia coli ATCC 25922 and Pseudomonaa aeruginosa ATCC 27853. Ten compounds showed an antibacterial activity against Enterococcus faecalis ATCC 29212 and Staphylococcus aureus ATCC 29213 with a range of the minimum inhibitory concentrations (MICs) between 16 and 125 micrograms/ml. None of the compounds exhibited antimicrobial activity against the gram-negative strains E. coli ATCC 25922 or Pseudomonas aeruginosa ATCC 29213 with a concentration range between 4 and 500 micrograms/ml. PMID:9553688

Sülü, M; Küçükbay, H; Durmaz, R; Günal, S

1998-03-01

369

Antifungal activity of rhodium, iridium, and ruthenium tripodal phosphine complexes.  

PubMed

Twenty-eight rhodium, iridium or ruthenium complexes were evaluated for their in vitro antifungal activities against Candida albicans and Candida tropicalis. Fourteen compounds showed an antifungal activity against C. albicans and C. tropicalis with a range of the minimum inhibitor concentrations (MICs) between 16 and 250 micrograms/mL. PMID:10946408

Sülü, M; Küçükbay, H; Durmaz, R; Günal, S

2000-01-01

370

40 CFR 180.225 - Phosphine; tolerances for residues.  

Code of Federal Regulations, 2013 CFR

...TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Specific Tolerances § 180.225 ...Residues resulting from fumigation of processed food: Commodity Parts per million Processed food 0.01 (4) Residues resulting...

2013-07-01

371

A second monoclinic modification of triphenyl-phosphine oxide hemihydrate  

PubMed Central

In the crystal of the title compound, C18H15OP·0.5H2O, a water molecule links to two adjacent triphenylphosphine molecules by way of O—H?O hydrogen bonds. The crystal is twinned, the minor twin component being 36%.

Ng, Seik Weng

2009-01-01

372

One-Pot Phosphine-Catalyzed Syntheses of Quinolines  

PubMed Central

In this study we developed an efficient one-pot procedure for the preparation of 3-substituted and 3,4-disubstituted quinolines from stable starting materials (activated acetylenes reacting with o-tosylamidobenzaldehydes and o-tosylamidophenones, respectively) under mild conditions. The reaction appears to operate under a general base catalysis mechanism, instigated by the ?-phosphonium enoate ?-vinyl anion generated in situ through nucleophilic addition of PPh3 to the activated alkyne. Michael addition of the deprotonated tosylamides to the activated alkynes and subsequent rapid aldol cyclization led to the formation of labile N-tosyldihydroquinoline intermediates. Driven by aromatization, detosylation of the dihydroquinoline intermediates occurred readily in the presence of dilute aqueous HCl to give the final quinoline products.

Khong, San; Kwon, Ohyun

2012-01-01

373

2-Amino-pyridinium diphenyl-phosphinate monohydrate  

PubMed Central

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

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

2009-01-01

374

Infrared multiphoton decomposition of phosphine sensitized by silicon tetrafluoride  

SciTech Connect

The decomposition of PH/sub 3/, sensitized by the multiphoton absorption of unfocussed infrared laser radiation by SiF/sub 4/, has been studied in the fluence range of 0.2-0.6 J/cm/sup 2/ and over a total pressure range of 1-16 torr. Absorption of radiation at 1025.3 cm/sup -1/ results in the formation of H/sub 2/ and a solid deposit which is probably composed of polymeric phosphorus hydrides of formula (PH)/sub x/. No significant amount of gaseous phosphorus compounds were detected, although it is possible that trace amounts of P/sub 2/(g) were formed. The effects of initial composition, pressure, fluence, and presence of foreign gases (He, N/sub 2/) on the yields of PH/sub 3/ decomposition and H/sub 2/ formation were examined. A mechanism is proposed which involves absorption of laser energy by SiF/sub 4/, followed by collisional energy transfer to PH/sub 3/ and subsequent unimolecular decomposition of PH/sub 3/ to PH and H/sub 2/. The mechanism is shown to be in reasonable accord with the experimental data.

Blazejowski, J.; Lampe, F.W.

1984-04-12

375

Zirconium and hafnium complexes containing bidentate diarylamido-phosphine ligands.  

PubMed

The first examples of mononuclear, structurally characterized triarylphosphine complexes of zirconium and hafnium are reported. The metathetical reactions of MCl4(THF)2 (M = Zr, Hf) with [iPrNP]Li(THF)2 ([iPrNP]- = N-(2-(diphenylphosphino)phenyl)-2,6-diisopropylanilide) or [MeNP]Li(THF)2 ([MeNP]- = N-(2-(diphenylphosphino)phenyl)-2,6-dimethylanilide) in toluene at -35 degrees C produced the corresponding [iPrNP]MCl3(THF) and [MeNP]2MCl2, respectively, in high yield. In contrast, attempts to prepare [MeNP]MCl3(THF) and [iPrNP]2MCl2 led to the concomitant formation of mono- and bis-ligated complexes, from which purification proved rather ineffective. The solution and solid-state structures of [iPrNP]MCl3(THF) and [MeNP]2MCl2 were studied by multinuclear NMR spectroscopy and X-ray crystallography. The geometry of these six-coordinate complexes is best described as a distorted octahedron in which the chloride ligands in [iPrNP]MCl3(THF) adopt a virtually meridional coordination mode whereas those in [MeNP]2MCl2 are trans to each other. PMID:15998044

Chien, Pin-Shu; Liang, Lan-Chang

2005-07-11

376

Dichloro-phosphinic bis-(2-chloro-eth-yl)amide  

PubMed Central

In the title compound, C4H8Cl4NOP, the two chloro­ethyl groups are not related by crystallographic symmetry. The difference in the conformation of the two groups is shown by their N—C—C—Cl torsion angles of 64.57?(15) and 175.62?(10)°.

Song, Erqun; Song, Yang

2013-01-01

377

Mechanism of phosphine photolysis. Application to Jovian atmospheric photochemistry.  

PubMed

PH3 is photolyzed to H2 and P2H4 and the P2H4 in turn is converted to red phosphorus. The initial quantum yield of H2 formation was redetermined and found to be 0.93 +/- 0.07. Red phosphorus was identified by its chemical properties and the absence of P-H stretching bands in its infrared spectrum. The reaction pathway was not changed by lowering the PH3 partial pressure from 90 to 11 torr or by performing the photolysis in a 70-fold excess of H2. The initial quantum yields at 11 torr of PH3 are phi P2H4 = 0.04 +/- 0.02 and phi H2 = 0.74 +/- 0.08. The initial rate of P2H4 formation was not affected by lowering the PH3 temperature to 227 or 157 K. The yield was greater at 157 K because the P2H4 condensed and was protected from further destruction. The initial quantum yields for the formation of P2H4 and H2 in PH3-NH3 mixtures were comparable to those observed for PH3 alone. Photolysis of mixtures in which NH3 was absorbing 90% of the light resulted in the rapid formation of P2H4. No N2 was formed when PH3-NH3 mixtures were photolyzed, suggesting that the destruction of NH3 is quenched by PH3. The application of these findings to Jovian atmospheric chemistry is discussed. PMID:11541956

Ferris, J P; Bossard, A; Khwaja, H

1984-01-01

378

[4-(Dimethyl-amino)-phen-yl]diphenyl-phosphine selenide  

PubMed Central

In the title compound, C20H20NPSe, the P atom lies in a distorted tetra­hedral environment. The Tolman cone angle is 157° indicating steric crowding at this atom. In the crystal, weak C—H?Se inter­actions create linked dimeric units and C—H?? inter­actions are also observed.

Davis, Wade L.; Muller, Alfred

2012-01-01

379

Chiral allene-containing phosphines in asymmetric catalysis  

PubMed Central

Traditionally, ligands used in asymmetric catalysis have contained either stereogenic atoms or hindered single bonds (atropisomerism), or both. Here we demonstrate that allenes, chiral 1,2-dienes, appended with basic functionality can serve as ligands for transition metals. We describe an allene-containing bisphosphine that, when coordinated to Rh(I), promotes the asymmetric addition of aryl boronic acids to ?-keto esters with high enantioselectivity. Solution and solid-state structural analysis reveals that one olefin of the allene can coordinate to transition metals generating bi- and tri-dentate ligands.

Cai, Feng; Pu, Xiaotao; Qi, Xiangbing; Lynch, Vincent; Radha, Akella; Ready, Joseph M.

2011-01-01

380

Activation of P C Bonds in Phosphines and Aromatic C H Bonds in Toluene by Phosphine Complexes of Dichloro- and Dimethylplatinum(II) in Hydrocarbon Media  

Microsoft Academic Search

According to GLC and 1H and 31P NMR data, lipophilic complexes of cis-dichloro- and cis-di- methylplatinum(II), PtX2(L)2 (X = Cl, L = PPh3 (I); X = Me, L = PPh3 (II); X = Cl, L = P(m-CH3C6H4)3 (III); X = Me, L = P(m-CH3C6H4)3 (IV)), II and III slowly react with toluene at 120 C to give products of activation

A. N. Vedernikov; A. G. Zazybin; A. B. Solomonov; B. N. Solomonov

381

Kinetics of substitution reactions of Fe II-phosphine complexes with Cl ?, Br ? and SCN ? in acetonitrile. A comparative study of complexes containing bidentate and tripodal phosphines  

Microsoft Academic Search

The kinetics of formation of FeLX+ complexes from FeLan22+ and X? [L ? P(CH2CH2PPh2)3, N(CH2CH2PPh2)3, (Ph2PCH2CH2PPh2)2; X ? Cl, Br, SCN; an = acetonitrile] has been studied in acetonitrile at 25.0°C and Et4NBF4 (0.05 mol dm?3). All the reactions seem to go through initial substitution of one coordinated acetonitrile by X? to form FeLX+, although in some cases the reaction

M. Angeles Máñez; M. Jesús Fernández-Trujillo; Manuel G. Basallote

1996-01-01

382

Paramagnetic Rh(III) complexes from reactions of phosphines with hydride-bridged and nonbridged rhodium phthalocyanine dimers: Metal-to-ligand charge transfer induced by phosphines  

SciTech Connect

The paramagnetic rhodium phthalocyanine complex (RPc)(PMe{sub 3}){sub 2}Rh (4) (RPc = dianion of 1,4,8,11,15,18,22,25-octa-n-pentylphthalocyanine) has been prepared by the reaction of trimethylphosphine (PMe{sub 3}) with hydride-bridged and nonbridged rhodium phthalocyanine dimers. The reaction of the {mu}-hydrido complex (RPcH)Rh({mu}-H)Rh(RPc) (5) (RPcH = RPc with one of its meso nitrogens protonated) with PMe{sub 3} at {minus}10 C produces (RPc)(PMe{sub 3})RhH (6), which further reacts with PMe{sub 3} to produce 4 and H{sub 2} at higher temperatures. If the solution of 6 is allowed to warm in the absence of free PMe{sub 3}, H{sub 2} is also liberated and 6 is converted to an equal number of moles of 4 and [(RPc)Rh]{sub 2}(PMe{sub 3}) (7). In contrast, the reaction of 5 with pyridine (py) produces (RPc)(py)-RhH (11), which does not react with additional pyridine. Alternatively, 4 is generated by the reaction of the Rh-Rh bonded dimer [(RPc)Rh]{sub 2} (1) with PMe{sub 3}. In this reaction, the formation of 7 as an intermediate may be shown by the titration of 1 with PMe{sub 3}. Complex 1 reacts with 4 to produce (RPc)Rh{sup {minus}} (10) and (RPc)(PMe{sub 3}){sub 2}-Rh{sup +} (9). A redox exchange between 4 and 9 ensues. The cobalt analogue of 4, i.e., (RPc)(PMe{sub 3}){sub 2}Co (12), was generated reversibly by the reaction of (RPc)Co (13) with PMe{sub 3} at low temperatures. The {sup 1}H NMR and the ESR spectra of 4, 12, and 13 indicate that while 13 is a metal-centered radical, 4 and 12 are best described as ligand-centered radicals.

Chen, M.J.; Utschig, L.M.; Rathke, J.W. [Argonne National Lab., IL (United States)

1998-11-02

383

Reactions of Elemental Phosphorus and Phosphines with Electrophiles in Superbasic Systems: XII. Synthesis of Unsymmetrical Tertiary Phosphine Oxides from Red Phosphorus and Organyl Halides  

Microsoft Academic Search

Alkyldibenzyl- and benzyldialkylphosphine oxides were prepared in one stage by direct phosphorylation of a mixture of alkyl bromides and benzyl chloride with red phosphorus under the conditions of phase-transfer catalysis (concentrated aqueous KOH solution-dioxane-benzyltriethylammonium chloride).

N. K. Gusarova; S. I. Shaikhudinova; N. I. Ivanova; A. M. Reutskaya; A. I. Albanov; B. A. Trofimov

2001-01-01

384

Paramagnetic effects on the NMR spectra of "diamagnetic" ruthenium(bis-phosphine)(bis-semiquinone) complexes.  

PubMed

Ligand substitution on cis-Ru(PPh(3))(2)(1,2-O(2)C(6)H(4))(2) gives cis-RuL(1)L(2)(1,2-O(2)C(6)H(4))(2) (L(1) = PPh(3), L(2) = P(OPh)(3), PBu(3); L(1) = L(2) = PBu(3), P(OMe)(3)). Syntheses of cis-Ru(PPh(3))(2)(3,4-O(2)C(6)H(2)(5-OH)CO(2)Me)(2) and cis-Ru(PPh(3))(2)(AGSQ)(2) (AGSQ = the semiquinone derived from 1,2,3-trihydroxyanthracene-9,10-dione) are also reported. The upfield chemical shifts and line broadening of the semiquinone 4,5-proton resonances in the NMR spectra indicate that these complexes, while having no detectable magnetic moments, have a weak, temperature-, ligand- and solvent-variable residual paramagnetism, not previously recognized in this series. Density functional theory (DFT) calculations predict a low-lying triplet state, about 14 kJ/mol (0.15 eV) above the singlet ground state. The paramagnetic effects on the NMR spectra are attributed to singlet-triplet equilibria. Temperature dependence of the proton resonances of the semiquinone rings of cis-Ru(PPh(3))(2)(1,2-O(2)C(6)H(4))(2) was used to calculate the singlet-triplet free energy difference as 17.5-18.0 kJ/mol in toluene. PMID:19400557

Le Guennic, Boris; Floyd, Tavon; Galan, Brandon R; Autschbach, Jochen; Keister, Jerome B

2009-06-15

385

Cubane and step-form structures of dilithium bis(aryloxy)phosphines.  

PubMed

The lithium complexes RP(3,5-tBu2C6H2OLi)2(THF)4, where R = Ph or i Pr, (R[OPO]Li2)2(THF)4, synthesized by reaction of the 2-bromo-4,6-di-tert-butylphenol with BuLi and the appropriate dichlorophosphine, possess solid state structures composed of lithium oxide tetragons arranged in a step-form or face sharing half-cubane arrangements. Incorporation of excess lithium aryloxide results in the formation of complexes that display an extended step-form structure, [Ph[OPO]Li2(ArOLi)]2, or a distorted cubane arrangement of tetragons, [iPr[OPO]Li3Cl(ArOLi)](THF)3. PMID:18239836

Carmichael, Christopher D; Fryzuk, Michael D

2007-11-29

386

Rat liver injury following normothermic ischemia is prevented by a phosphinic matrix metalloproteinase inhibitor  

Microsoft Academic Search

Hepatic ischemia occurs in liver transplantation, hemodynamic or cardiogenic shock, and liver resection associated with trauma or tumor. Ischemia\\/reperfusion (I\\/R) injury results in microcirculation failure followed by apoptosis and necrosis. Matrix metalloproteinases (MMPs) are involved in many physiological and pathological processes, but their expression and function during liver I\\/R remains poorly documented. In this study, we evaluated the expression of

Raffaele Cursio; Bernard Mari; Krystel Louis; Philippe Rostagno; Marie-Christine Saint; Jean Giudicelli; Virginie Bottero; Patrick Anglard; Athanasios Yiotakis; Vincent Dive; Jean Gugenheim; Patrick Auberger

2001-01-01

387

Carbonyl Difluoride: Reactions with Metal-Phosphine Complexes. (Reannouncement with New Availability Information).  

National Technical Information Service (NTIS)

Carbonyl difluoride (COF2) is a versatile and nondestructive fluorine-transfer reagent as demonstrated by the ready introduction of fluorine into a variety of P-H, N-H or C-H containing compounds. Furthermore, metal oxides may be converted into metal fluo...

O. D. Gupta R. L. Kirchmeier J. M. Shreeve

1991-01-01

388

trans-(Ethene-1,2-di-yl)bis-(diphenyl-phosphine selenide)  

PubMed Central

In the title mol­ecule, C26H22P2Se2, both P atoms have distorted tetra­hedral environments, resulting in effective cone angles of 177 and 174°. Inversion twinning was detected and refined to a ratio of 0.35:0.65. Weak inter­molecular C—H?Se inter­actions are observed.

Phasha, Zanele; Makhoba, Sizwe; Muller, Alfred

2012-01-01

389

Synthesis and characterization of gold nanoparticles stabilized by palladium(II) phosphine thiol  

Microsoft Academic Search

This work is focused on the synthesis of innovative hybrids made by linking gold nanoparticles to protected organometallic Pd(II) thiolate. The organometallic protected Pd(II) thiolate, i.e. trans-thioacetate-ethynylphenyl-bis(tributylphosphine)palladium(II) has been synthesized, in situ deprotected and linked to Au nanoparticles. In this way new hybrid, with a direct link between Pd(II) and Au nanoparticles through a single S bridge, has been isolated.

Floriana Vitale; Rosa Vitaliano; Chiara Battocchio; Ilaria Fratoddi; Emanuela Piscopiello; Leander Tapfer; Maria Vittoria Russo

2008-01-01

390

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

Microsoft Academic Search

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

Nam T. S. Phan; Ha V. Le

2011-01-01

391

Synthesis of glyoxylyl peptides using a phosphine labile ?,??-diaminoacetic acid derivative  

Microsoft Academic Search

We describe in this letter the preparation of a novel protected ?,??-diaminoacetic acid derivative that acts as a masked glyoxylic acid equivalent. The reagent could easily be introduced on a peptide chain using standard Fmoc\\/tert-butyl solid-phase methods and resisted to the TFA treatment allowing the deprotection and cleavage of the peptide. Unmasking of the glyoxylyl group was performed in solution

Samia Far; Oleg Melnyk

2004-01-01

392

Kinetics and mechanism of the oxidation of phosphinic, phenylphosphinic and phosphorous acids by benzyltrimethylammonium dichloroiodate  

Microsoft Academic Search

Oxidation of lower phosphorus oxyacids by benzyltrimethylammonium dichloroiodate (BTACI), in the presence of zinc chloride,\\u000a resulted in the formation of the corresponding oxyacids with phosphorus in a higher oxidation state. The reaction is first\\u000a order with respect to the concentration of BTACI, oxyacid and zinc chloride. The reaction exhibited the presence of a substantial\\u000a kinetic isotope effect. Addition of benzyltrimethylammonium

Deepa Suri; Seema Kothari; Kalyan K Banerji

1997-01-01

393

Photophysics of the Adsorbed Bipyridyl Complexes of Ruthenium(II) with Phosphines  

NASA Astrophysics Data System (ADS)

Luminescence of the ruthenium(II) complexes cis-Ru(bpy)2(CN)2 ( I), cis-[Ru(bpy)2(PPh3)CN](BF4) ( II), and cis-Ru(bpy)(dppe)(CN)2 ( III)[bpy=2.2'-bipyridyl, PPh3=triphenylphosphine, dppe=1,2-bis(diphenylphosphino)ethane], adsorbed on silicon oxide (Aerosil) were studied at a temperature of 77 K. The luminescence spectra, decay times, and quantum yields were measured, and the intermolecular rate constants of radiative transitions and nonradiative decay of the excited electronic state with the metal-to-ligand charge transfer (MLCT) were determined. It is found that the adsorption of the complex is accompanied by a decrease in the energy of the radiative MLCT state and by a considerable acceleration of its nonradiative decay. It is concluded that the interaction of the complexes with the surface adsorption centers occurs via formation of a strong hydrogen bond with a hydroxyl-hydrate cover, the interaction of complexes in the 3MLCT state being stronger than in the ground state. The additive (in the number of phosphorus atoms coordinated to the central ruthenium ion), a shift of the absorption and luminescence bands to shorter wavelengths in the sequence of complexes I-III, is retained when the complexes transform from solutions to the absorbed state.

Litke, S. V.; Mezentseva, T. V.; Litke, A. S.; Lyalin, G. N.; Ershov, A. Yu.

2002-02-01

394

Synthesis of 3,3'-spirocyclic oxindoles via phosphine catalyzed [4 + 2] cyclizations.  

PubMed

Triphenylphosphine promoted reactions between 3-arylideneoxindoles and ?-aryl-substituted penta-2,3-dienoates afford an unprecedented access to spirocyclic oxindoles with functionalized six-membered rings. In these new [4 + 2] cyclization processes, the allenoates operate as the four-carbon synthons, thanks to the involvement of the substituted ?-carbons. These reactions give excellent control of the relative stereochemistry of the three stereogenic centers. The stereochemistry of the final product has been ascertained by X-ray diffraction studies. PMID:23879566

Gicquel, Maxime; Gomez, Catherine; Retailleau, Pascal; Voituriez, Arnaud; Marinetti, Angela

2013-07-23

395

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

PubMed Central

In the title compound, C24H9F18OP, an intra­molecular 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 trifluoro­methyl 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 inter­molecular C—H?O and C—H?F inter­actions.

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

2009-01-01

396

Calcium-centred phosphine oxide reactivity: P-C metathesis, reduction and P-P coupling.  

PubMed

Reactions of triphenylphosphine oxide and diphenylphosphine oxide with calcium alkyls and amides in the presence of PhSiH(3) occur to give P-C bond cleavage, P(V) to P(III) reduction and P-P coupling. PMID:20379562

Hill, Michael S; Mahon, Mary F; Robinson, Thomas P

2010-01-28

397

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

PubMed

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

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

2012-10-29

398

Method for the synthesis of phosphinic acids from hypophosphites V. The synthesis of pseudo-?,?-dipeptides  

Microsoft Academic Search

Summary. The method for the synthesis of 2-substituted 2-hydroxycarbonylethyl-1-aminoalkylphosphinic acids (I) (pseudo-?,?-dipeptides) from ammonium and potassium hypophosphites (II) is described. The proposed route to the synthesis of pseudo-?,?-dipeptides consists in addition hypophosphite to acrylic compounds and formation of the first phosphorus–carbon bond with following addition of aminoacid fragment and formation of the second phosphorus–carbon bond. The key intermediates of the

L. F. Rozhko; V. V. Ragulin

2005-01-01

399

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

SciTech Connect

We report blue phosphorescent organic light-emitting devices (OLEDs) using an ambipolar host, N-(4-diphenylphosphoryl phenyl) carbazole (MPO12), doped with iridium (III) bis[4,6-difluorophenyl)-pyridinato-N,C2´]picolinate (FIrpic). The external quantum efficiency and operating voltage is 9.1±0.1% and 4.8 V, respectively, measured at a brightness of 800 cd/m2 with no outcoupling enhancement. By varying the layer structure of the OLEDs, we show that MPO12 is capable of transporting both electrons and holes, in contrast to previous demonstrations using diphosphine oxides, which only transported electrons. The improved hole transport results in improved device efficiency.

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

2008-02-28

400

Gold(I)-phosphine catalyst for the highly chemoselective dehydrogenative silylation of alcohols.  

PubMed

[reaction: see text] A gold(I) complex of Xantphos AuCl(xantphos) catalyzes the dehydrogenative silylation of alcohols with high chemoselectivity and solvent tolerance. It is selective for the silylation of hydroxyl groups in the presence of alkenes, alkynes, alkyl halides (RCl, RBr), ketones, aldehydes, conjugated enones, esters, and carbamates. PMID:15987190

Ito, Hajime; Takagi, Katsuhiro; Miyahara, Takahiro; Sawamura, Masaya

2005-07-01

401

Rapid cross-linking of elastin-like polypeptides with (hydroxymethyl)phosphines in aqueous solution.  

PubMed

In situ gelation of injectable polypeptide-based materials is attractive for minimally invasive in vivo implantation of biomaterials and tissue engineering scaffolds. We demonstrate that chemically cross-linked elastin-like polypeptide (ELP) hydrogels can be rapidly formed in aqueous solution by reacting lysine-containing ELPs with an organophosphorous cross-linker, beta-[tris(hydroxymethyl)phosphino]propionic acid (THPP) under physiological conditions. The mechanical properties of the cross-linked ELP hydrogels were largely modulated by the molar concentration of lysine residues in the ELP and the pH at which the cross-linking reaction was carried out. Fibroblasts embedded in ELP hydrogels survived the cross-linking process and were viable after in vitro culture for 3 days. DNA quantification of ELP hydrogels with encapsulated fibroblasts indicated that there was no significant difference in DNA content between day 0 and day 3 when ELP hydrogels were formed with an equimolar ratio of THPP and lysine residues of the ELPs. These results suggest that THPP cross-linking may be a biocompatible strategy for the in situ formation of cross-linked hydrogels. PMID:17411091

Lim, Dong Woo; Nettles, Dana L; Setton, Lori A; Chilkoti, Ashutosh

2007-04-06

402

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

PubMed

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

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

2013-09-01

403

A computational study of phosphine ligand effects in Suzuki–Miyaura coupling  

Microsoft Academic Search

DFT calculations have been used to explore the full catalytic cycle of the Suzuki–Miyaura coupling between PhBr and PhB(OH)3? with four different palladium monophosphine catalysts derived from Pd(PMe3)2, Pd(P(CF3)3)2, Pd(PPh3)2 and Pd(PtBu3)2. All the steps of the reaction have been studied and the differences between the ligands have been analyzed; special attention has been devoted to the ligand dissociation and

Jesús Jover; Natalie Fey; Mark Purdie; Guy C. Lloyd-Jones; Jeremy N. Harvey

2010-01-01

404

Electron and hole transport in a wide bandgap organic phosphine oxide for blue electrophosphorescence  

Microsoft Academic Search

We report blue phosphorescent organic light-emitting devices (OLEDs) using an ambipolar host, N-(4-diphenylphosphoryl phenyl) carbazole (MPO12), doped with iridium (III) bis[(4,6-difluorophenyl)-pyridinato-N,C2']picolinate (FIrpic). The external quantum efficiency and operating voltage is 9.1(+\\/-0.1)% and 4.8 V, respectively, measured at a brightness of 800 cd\\/m2 with no outcoupling enhancement. By varying the layer structure of the OLEDs, we show that MPO12 is capable

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

2008-01-01

405

Electron and hole transport in a wide bandgap organic phosphine oxide for blue electrophosphorescence  

Microsoft Academic Search

We report blue phosphorescent organic light-emitting devices (OLEDs) using an ambipolar host, N-(4-diphenylphosphoryl phenyl) carbazole (MPO12), doped with iridium (III) bis[(4,6-difluorophenyl)-pyridinato-N,C2?]picolinate (FIrpic). The external quantum efficiency and operating voltage is 9.1(±0.1)% and 4.8 V, respectively, measured at a brightness of 800 cd?m2 with no outcoupling enhancement. By varying the layer structure of the OLEDs, we show that MPO12 is capable

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

2008-01-01

406

Optical diagnostic studies of trimethyl phosphine-containing radio-frequency discharges  

Microsoft Academic Search

We have investigated the decomposition of P(CH3)3 in 13-MHz, radio-frequency discharges in He and H2. Relative concentrations of atomic phosphorus were estimated actinometrically by measuring P emission intensities, relative to Ar, while quantitative, relative P2 number densities were measured by ArF excimer laser-induced fluorescence. A radiative lifetime of 10.5±1.0 ns was measured for the v'=11 level of the C1?u+ state,

L. Brown; V. M. Donnelly; V. R. McCrary

1987-01-01

407

(?6-p-Cymene)bis-(trichlorido-stannyl)(triethoxy-phosphine-?P)ruthenium(II)  

PubMed Central

In the title complex, [RuSn2(C10H14)Cl6(C6H15O3P)], the Ru—Sn bond lengths [2.5619?(3) and 2.5669?(3)?Å] are about 0.3?Å shorter than the sum of the covalent Ru and Sn radii (1.46 + 1.39 = 2.85?Å), in line with other structurally characterized arene ruthenium trichlorido­stannyl derivatives. The Ru(II) atom is surrounded by a para-cymene, a triethylphosphite and two trichloridostannyl ligands in a typical piano-stool coordination.

Shapovalov, Sergey S.; Therrien, Bruno

2009-01-01

408

Mechanism of alterations in isolated rat liver mitochondrial function induced by gold complexes of bidentate phosphines.  

PubMed

Au(DPPE)+2 (bis[1,2-bis(diphenylphosphino)ethane] gold(I] is an organo-gold antineoplastic agent that has anti-tumor activity in a variety of in vitro cell lines and in vivo rodent tumor models. Preliminary studies suggested that this compound represented a novel class of inhibitors of mitochondrial function. The purpose of this study was, therefore, to determine the mechanism of mitochondrial dysfunction induced by Au(DPPE)+2. Au(DPPE)+2 induced a rapid, dose-related collapse of the inner mitochondrial membrane potential (EC50 = 28.0 microM) that was not potentiated by Ca2+ preloading. Au(DPPE)+2-induced dissipation of mitochondrial membrane potential was accompanied by an efflux of Ca2+ from mitochondria upon exposure to Au(DPPE)+2. Ca2+ efflux in these experiments was via a reversal of the Ca2+ uniporter as efflux could be inhibited with ruthenium red. Au(DPPE)+2 did not increase the permeability of mitochondria to oxalacetate, indicating that the collapse of membrane potential may not be a result of gross increased inner membrane permeability. However, Au(DPPE)+2 may mediate an increased permeability of the inner membrane to cations and protons. Au(DPPE)+2 caused passive swelling in potassium acetate buffer in the absence of valinomycin, suggesting Au(DPPE)+2 facilitated the exchange of H+ and K+. Ca2+ cycling was not extensive and did not contribute to the decrease in membrane potential. These data suggest that one possible mechanism of Au(DPPE+2-induced uncoupling of mitochondrial oxidative phosphorylation is via increased permeability of the inner mitochondrial membrane to cations. The disruption of mitochondrial function may be a key process leading to hepatocyte cell injury by this drug. PMID:2457018

Hoke, G D; Rush, G F; Bossard, G F; McArdle, J V; Jensen, B D; Mirabelli, C K

1988-08-15

409

The Mechanochemical Reaction of Palladium(II) Chloride with a Bidentate Phosphine  

ERIC Educational Resources Information Center

|This experiment describes the reaction of palladium(II) chloride with 1,5-bis(diphenylphosphino)pentane by grinding the two powders together in the solid state. The product is the precursor for the metalation reaction at one of the methylene carbon atoms of the ligand's backbone. The final product is known to be a catalyst for Suzuki-Miyaura…

Berry, David E.; Carrie, Philippa; Fawkes, Kelli L.; Rebner, Bruce; Xing, Yao

2010-01-01

410

A polymer-bound bidentate-phosphine-palladium complex as a catalyst in the Heck arylation  

SciTech Connect

Polymer-supported 1,2-bis(diisopropylphosphino)benzene Pd(II) complex 2 shows a higher level of catalytic activity than the structurally analogous monomeric Pd(II) complex 1 in the Heck arylation of methyl acrylate by iodobenzene. The polymer-supported Pd(II) complex has a much higher turnover number (by more than 1 order of magnitude) than either 1 or Pd(OAc){sub 2}/PPh{sub 3} at synthetically useful concentrations of reagents. The reaction rate of the monomeric Pd(II) complex 1 is enhanced by electrochemical prereduction of Pd(II) to Pd(0). Deactivation in homogeneous solution via aggregation of the reactive complex to insoluble palladium metal clusters or by equilibration to a sterically blocked tetraphosphino complex is proposed to explain the higher catalytic activity of the polymer-supported Pd(II) complex than of its structurally analogous soluble monomer.

Wang, P.W.; Fox, M.A. [Univ. of Texas, Austin, TX (United States)

1994-09-09

411

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

NASA Astrophysics Data System (ADS)

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

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

2011-11-01

412

Bis[bis-(diphenyl-thio-phosphin-yl)amido-?2 S,S?]platinum(II)  

PubMed Central

In the title compound, [Pt(C24H20NP2S2)2], the Pt atom is in a distorted square-planar environment and contains two six-membered carbon-free chelate rings, one in twist-boat and the other in a half-chair conformation. Two phenyl groups are disordered over two set of sites in ratios of 0.721?(13):0.279?(13) and 0.71?(7):0.29?(7).

Guzelsoylu, Cemal; Irisli, Sevil; Buyukgungor, Orhan

2011-01-01

413

Phosphine and thiophene cyclopalladated complexes: hydrolysis reactions in strong acidic media.  

PubMed

The mechanisms for the hydrolysis of organopalladium complexes [Pd(CNN)R]BF(4) (R=P(OPh)(3), PPh(3), and SC(4)H(8)) were investigated at 25?°C by using UV/Vis absorbance measurements in 10?% v/v ethanol/water mixtures containing different sulphuric acid concentrations in the 1.3-11.7?M range. In all cases, a biphasic behavior was observed with rate constants k(1obs), which corresponds to the initial step of the hydrolysis reaction, and k(2obs), where k(1obs)>k(2obs). The plots of k(1obs) and k(2obs) versus sulfuric acid concentration suggest a change in the reaction mechanism. The change with respect to the k(1obs) value corresponds to 35?%, 2?%, and 99?% of the protonated complexes for R=PPh(3), P(OPh)(3), and SC(4)H(8), respectively. Regarding k(2obs), the change occurred in all cases at about 6.5?M H(2)SO(4) and matched up with the results reported for the hydrolysis of the 2-acetylpyridinephenylhydrazone (CNN) ligand. By using the excess acidity method, the mechanisms were elucidated by carefully looking at the variation of k(i),(obs) (i=1,2) versus cH+. The rate-determining constants, k(0,A-1), k(0,A-2), and k(0,A-SE2) were evaluated in all cases. The R=P(OPh)(3) complex was most reactive due to its ?-acid character, which favors the rupture of the trans nitrogen-palladium bond in the A-2 mechanism and also that of the pyridine nitrogen-palladium bond in the A-1 mechanism. The organometallic bond exerts no effect on the relative basicity of the complexes, which are strongly reliant on the substituent. PMID:21125574

García, Begoña; Hoyuelos, Francisco J; Ibeas, Saturnino; Muñoz, María S; Navarro, Ana M; Peñacoba, Indalecio A; Leal, José M

2010-12-01

414

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

SciTech Connect

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.

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

1995-02-01

415

Intensely luminescent homoleptic alkynyl decanuclear gold(I) clusters and their cationic octanuclear phosphine derivatives.  

PubMed

Treatment of Au(SC(4)H(8))Cl with a stoichiometric amount of hydroxyaliphatic alkyne in the presence of NEt(3) results in high-yield self-assembly of homoleptic clusters (AuC(2)R)(10) (R = 9-fluorenol (1), diphenylmethanol (2), 2,6-dimethyl-4-heptanol (3), 3-methyl-2-butanol (4), 4-methyl-2-pentanol (4), 1-cyclohexanol (6), 2-borneol (7)). The molecular compounds contain an unprecedented catenane metal core with two interlocked 5-membered rings. Reactions of the decanuclear clusters 1-7 with gold-diphosphine complex [Au(2)(1,4-PPh(2)-C(6)H(4)-PPh(2))(2)](2+) lead to octanuclear cationic derivatives [Au(8)(C(2)R)(6)(PPh(2)-C(6)H(4)-PPh(2))(2)](2+) (8-14), which consist of planar tetranuclear units {Au(4)(C(2)R)(4)} coupled with two fragments [AuPPh(2)-C(6)H(4)-PPh(2)(AuC(2)R)](+). The titled complexes were characterized by NMR and ESI-MS spectroscopy, and the structures of 1, 13, and 14 were determined by single-crystal X-ray diffraction analysis. The luminescence behavior of both Au(I)(10) and Au(I)(8) families has been studied, revealing efficient room-temperature phosphorescence in solution and in the solid state, with the maximum quantum yield approaching 100% (2 in solution). DFT computational studies showed that in both Au(I)(10) and Au(I)(8) clusters metal-centered Au ? Au charge transfer transitions mixed with some ?-alkynyl MLCT character play a dominant role in the observed phosphorescence. PMID:22686420

Koshevoy, Igor O; Chang, Yuh-Chia; Karttunen, Antti J; Selivanov, Stanislav I; Jänis, Janne; Haukka, Matti; Pakkanen, Tapani; Tunik, Sergey P; Chou, Pi-Tai

2012-06-11

416

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

NASA Astrophysics Data System (ADS)

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

Müller, Holger S. P.

2013-11-01

417

rac-[2-(Dicyclohexylphosphanyl)phenyl](phenyl)phosphinic diisopropyl-amide-borane hemihydrate  

PubMed Central

In the title compound, C30H48BNOP2·0.5H2O, the water molecule is disordered about an inversion centre. Both phospho­rus atoms shows distortions in their tetra­hedral environments with the cyclo­hexyl substituents disordered over two orientations in a 0.851?(3):0.149?(3) occupancy ratio. The crystal structure is assembled via O—H?O inter­actions between pairs of phosphininc amide mol­ecules and water molecules, creating hydrogen-bonded dimers with graph-set R 2 4(8) along [001]. Weak C—H?O inter­actions are also observed.

Evans, Stephen J.; Renison, C. Alicia; Williams, D. Bradley G.; Muller, Alfred

2013-01-01

418

Characterization of Phosphine Production During Extended Storage of the KM03 Red Phosphorus Floating Smoke Pot.  

National Technical Information Service (NTIS)

The U.S. Marine Corps (USMC) Floating Smoke Pot (FSP) MK 7 MOD 0 Program was established to redesign the previously fielded M4A2 Hexachloroethane (HC) FSP. Although the HC pots were extremely effective as an obscurant, there were safety concerns from manu...

C. L. Crouse D. A. McCaskey K. L. Crouse R. L. Kristovich

2011-01-01

419

Structure and properties of bis{[2-(4- tert -butyl)phen]ethyl}phosphine sulfide  

Microsoft Academic Search

Previously unknown bis[2-(4-tert-butyl)phen]ethylphosphine sulfide is obtained with a high yield from 4-tert-butyl styrene, red phosphorus, and elemental sulfur. Using single crystal XRD, multinuclear NMR, IR, and UV spectroscopy,\\u000a it is found that the phosphorus atom is four-coordinated in the bis[2-(4-tert-butyl)phen]ethylphosphine sulfide molecule (regardless of the phase state of the compound: crystal, solution). By the example\\u000a of phosphorylation of bis[2-(4-tert-butyl)phen]ethylphosphine sulfide

N. K. Gusarova; S. F. Malysheva; N. A. Belogorlova; O. N. Kazheva; A. N. Chekhlov; G. G. Aleksandrov; O. A. D’yachenko; L. M. Sinegovskaya; B. A. Trofimov

2010-01-01

420

Infrared spectrum of a symmetrical phosphine-ozone complex in solid argon  

SciTech Connect

Cocondensation of Ar/PH/sub 2/ and Ar/O/sub 2/ samples at 12-18 K has produced sharp satellite absorptions at 1037.3 cm/sup -1/ below nu/sub 3/ of O/sub 3/ at 1039.9 cm/sup -1/, at 988.5 and 986.3 cm/sup -1/ below nu/sub 2/ of PH/sub 3/ at 994 cm/sup -1/, and at 705.2 cm/sup -1/ above nu/sub 2/ of O/sub 3/ at 704.4 cm/sup -1/. These bands, which photolyzed with red visible light and were reproduced on sample warming to allow reagent diffusion, are assigned to the PH/sub 3/-O/sub 3/ complex. A sharp sextet in /sup 16,18/O/sub 3/ experiments indicated a symmetrical attachment of ozone in the complex. The red visible photolysis is postulated to involve a charge-transfer mechanism. 32 references, 3 figures, 2 tables.

Withnall, R.; Hawkins, M.; Andrews, L.

1986-02-13

421

Electronic and steric effects in gold(i) phosphine thiolate complexes.  

PubMed

The unusual yellow color of Au(2)(dppm)(SR)(2) (R = 4-tolyl; dppm = diphenylphosphinomethane) is attributed to a red-shift in the S-->Au charge transfer caused by destabilization of the sulfur highest occupied molecular orbital (HOMO). Variable temperature experiments show two broad bands at -80 degrees C in the (31)P{(1)H} NMR spectrum of Au(2)(dppm)(SR)(2) and the activation energy for interconversion is 10 kcal/mol. Only one sharp band is observed down to -80 degrees C in the spectrum of the white complex, Au(2)(dppe)(SR)(2) (dppe = diphenylphosphinoethane). Molecular mechanics calculations on Au(2)(dppm)(SR)(2) and Au(2)(dppe)(SR)(2) reveal that, for Au(2)(dppe)(SR)(2), a series of maxima and minima, separated by 2.5 kcal/mol, occur every 120 degrees which is consistent with rotation around an unhindered carbon-phosphorus single bond. The Au atoms are not within bonding distance in any conformation. Computational results for Au(2)(dppm)(SR)(2) indicate one minimum energy structure in which the Au-P bonds are anti. There is a high energy conformation (9 kcal/mol above the global minimum) where overlap between golds is maximized. The implications of gold-gold bonding in this complex are discussed. The steric influence of the thiolate ligand has been examined by synthesizing a series of dinuclear gold(I) complexes in which the steric properties of the thiolate are varied: Au(2)(dppm)(SR)(2) (R = 2,6-dichlorophenyl; 2,6-dimethylphenyl; 3,5-dimethylphenyl). The 2,6-disubstituted complexes are white, while the 3,5-dimethyl complex is yellow. These results, along with VT-NMR experiments, are consistent with the conclusion that the more sterically-bulky thiolates hinder the close approach of the golds in the dinuclear complexes. PMID:18476259

Foley, J; Fort, R C; McDougal, K; Bruce, M R; Bruce, A E

1994-01-01

422

Inorganic Coordination Polymers. VIII. Cobalt(II) and Zinc(II) Phosphinate Polymers and Copolymers.  

National Technical Information Service (NTIS)

The preparation, properties, X-ray powder patterns, and TGA curves are given for cobalt(II) dimethyl-, methylphenyl-, and diphenylphosphinate. The polymeric character of cobalt(II) methylphenylphosphinate is demonstrated by its colligative properties and ...

S. H. Rose B. P. Block

1965-01-01

423

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

PubMed

A novel kind of functional organic microporous polymer is designed by introducing polar organic groups (P=O and P=S) and electron-rich heterocyclic into the framework to obtain high carbon dioxide capture capacity. The estimated Brunauer-Emmett-Teller (BET) surface areas of these polymers are about 600 m(2) g(-1) and the highest CO2 uptake is 2.26 mmol g(-1) (1.0 bar/273 K). Interestingly, the polymer containing P=O groups shows greater CO2 capture capacity than that containing P=S groups at the same temperature. In addition, these polymers show high isosteric heats of CO2 adsorption (28.6 kJ mol(-1) ), which can be competitive with some nitrogen-rich networks. Therefore, these microporous polymers are promising candidates for carbon dioxide capture. PMID:23757097

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

2013-06-12

424

Phosphine-Triggered Co-catenation of :BR and CO on an Iron Atom.  

PubMed

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

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

2013-08-23

425

Highly enantioselective rh-catalysed hydrogenation of 1-alkyl vinyl esters using phosphine-phosphoramidite ligands.  

PubMed

MatPhos, a good mate for hard tasks: The asymmetric hydrogenation of 1-alkyl vinyl esters, thwarted so far by mediocre ee values and low activities, can now be achieved with MatPhos/Rh catalysts with ee values of 96-99?% for a variety of substrates at low catalyst loadings (0.1-1?mol?%) and under mild conditions (5-20?bar H2 , room temperature). After hydrolysis, the corresponding chiral secondary alkyl alcohols can be obtained in high enantiopurities providing a general and practical route to this important product class. PMID:24027035

Konrad, Tina Maria; Schmitz, Pascal; Leitner, Walter; Franciò, Giancarlo

2013-09-11

426

Solar cells made by laser-induced diffusion directly from phosphine gas  

SciTech Connect

A new method for making p-n junctions based on immersion in a transparent dopant gas followed by irradiation with a pulsed laser is presented. An alexandrite laser was used, operating at 0.73 ..mu..m where photolysis of the dopant gas PH/sub 3/ does not occur. Multiple pulses of 2.2--2.7 J/cm/sup 2/ were used to make Si solar cells with total area efficiencies up to 8.6% without benefit of antireflection coatings.

Turner, G.B.; Tarrant, D.; Pollock, G.; Pressley, R.; Press, R.

1981-12-15

427

In vitro Phosphinate Methylation by PhpK from Kitasatospora Phosalacinea  

PubMed Central

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.

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

2011-01-01

428

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

PubMed

In ongoing attempts of directed synthesis of high-nuclearity Au-Pt carbonyl/phosphine clusters with [Ni6(CO)12]2- used as reducing agent and CO source, we have isolated and characterized two new closely related variable-stoichiometric trimetallic clusters, Pt3(Pt(1-x)Ni(x))(AuPPh3)2(mu2-CO)4(CO)(PPh3)3 (1) and Pt2(Pt(2-y)Ni(y))(AuPPh3)2(mu2-CO)4(CO)2(PPh3)2 (2). Their M4Au2 cores may be envisioned as substitutional disordered butterfly-based M4Au2 frameworks (M = Pt/Ni) formed by connections of the two basal M(B) atoms with both (Au-Au)-linked Au(PPh3) moieties. Based upon low-temperature CCD X-ray diffraction studies of eight crystals obtained from different samples, ligation-induced site-specific Pt/Ni substitutional disorder (involving formal insertion of Ni in place of Pt) in a given crystal was found to occur only at the one OC-attached basal M(B) site in 1 or at both OC-attached basal M(B) sites in 2 corresponding to a crystal composite of the Pt3(Pt(1-x)Ni(x))Au2 core in 1 or of the Pt2(Pt(2-y)Ni(y))Au2 core in 2; the Ph3P-attached M(B) site (M(B) = Pt) in 1 and two wingtip M(w) sites (M(w) = Pt) in 1 and 2 were not substitutionally disordered. The resulting variable stoichiometry of the M4Au2 core in 1 may be viewed as a crystal composite of two superimposed individual stereoisomers, Pt4(AuPPh3)2(mu2-CO)4(CO)(PPh3)3 (1a) and Pt3Ni(AuPPh3)2(mu2-CO)4(CO)(PPh3)3 (1b), in the averaged unit cell of a given crystal. Likewise, 2 represents the crystal-averaged composite of three individual stereoisomers, Pt4(AuPPh3)2(mu2-CO)4(CO)2(PPh3)2 (2a), Pt3Ni(AuPPh3)2(mu2-CO)4(CO)2(PPh3)2 (2b), and Pt2Ni2(AuPPh3)2(mu2-CO)4(CO)2(PPh3)2 (2c). Formal Ni substitution for Pt at only the basal M(B) site(s) in the four crystal composites each of 1 and 2 was found to vary widely from 17% to 79% Ni in 1 and from 21% to 95% Ni in 2. Nevertheless, reasonably close Pt/Ni occupancy factors were found within each of the four pairs of composite crystals selected from samples obtained from duplicate syntheses. Both 1 and 2 may be formally derived from the electronically equivalent classic butterfly Pt4(mu2-CO)5(PPh3)4 cluster by replacement of its bridging mu2-CO ligand spanning the basal M(B)-M(B) edge with two one-electron donating (Au-Au)-linked AuPPh3 moieties along with the substitution of a terminal CO in place of one or both M(B)-attached PPh3 ligands in 1 and 2, respectively; site-specific Pt/Ni substitutional disorder occurs only at the CO-attached M(B) sites. The variable-stoichiometric 1 and 2 re also electronically equivalent and geometrically related to the crystal-ordered butterfly-based Pt4(mu2-CO)4(PR3)4(mu3-HgX)2 clusters (R3 = Ph3, MePh2; X = CF3, Br, I). PMID:16688317

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

2006-02-14

429

Tris(thio-cyanato-?N)tris-(triphenyl-phosphine oxide-?O)europium(III)-(nitrato-?2 O,O?)bis-(thio-cyanato-?N)tris-(triphenyl-phosphine oxide-?O)europium(III) (1/1)  

PubMed Central

The title co-crystal, [Eu(NCS)3(C18H15OP)3][Eu(NCS)2(NO3)(C18H15OP)3], contains two distinct neutral complexes. Each complex has threefold symmetry about its central Eu3+ ion. As a result, the nitrate-containing mol­ecule contains disorder of its bidentate nitrate and two N-bound thio­cyanate anions, while the [Eu(NCS)3(OPPh3)3] complex is fully ordered. There is a weak ?–? stacking inter­action between the phenyl rings of the two mol­ecules [centroid–centroid distance = 4.138?(4)?Å].

Thames, Anthony T.; White, Frankie D.; Pham, Lam N.; Xiang, Kang Rui; Sykora, Richard E.

2012-01-01

430

New Ru complexes containing the N-tridentate bpea and phosphine ligands: consequences of meridional vs facial geometry.  

PubMed

The synthesis and isolation of the complex cis,fac-[RuIICl2(bpea)(PPh3)][3; bpea = N,N-bis(2-pyridylmethyl)ethylamine] and three geometrical isomers of the complex [RuIICl(bpea)(dppe)](BF4) [4; dppe = (1,2-diphenylphosphino)ethane], trans,fac (4a), cis,fac (4b), and mer(down) (4c), have been described (see Chart 1 for a drawing of their structures). These complexes have been characterized through analytical, spectroscopic (IR, UV/vis, and 1D and 2D NMR), and electrochemical (cyclic voltammetry) techniques. In addition, complexes 3, 4a, and 4b have been further characterized in the solid state through monocrystal X-ray diffraction analysis. The molecular and electronic structures of isomers 4a, 4b, 4c, and 4d (the mer(up) isomer) have also been studied by means of density functional theory (DFT) calculations. Furthermore, their low-energy electronic transitions have been simulated using time-dependent DFT approaches, which have allowed unraveling of their metal-to-ligand charge-transfer nature. Complexes 3 and 4a-c are capable of catalyzing H-transfer types of reactions between alcohols and aromatic ketones such as acetophenone and 2,2-dimethylpropiophenone (DP). A strong influence of the facial versus meridional geometry in the bpea ligand coordination mode is observed for these catalytic reactions, with the meridional isomer being much more active than the facial one. The meridional isomer is even capable of carrying out the H-transfer reaction of bulky substrates such as DP at room temperature. PMID:17173407

Mola, Joaquim; Rodríguez, Montserrat; Romero, Isabel; Llobet, Antoni; Parella, Teodor; Poater, Albert; Duran, Miquel; Solà, Miquel; Benet-Buchholz, Jordi

2006-12-25

431

rac-{[2-(Diphenyl-thio-phosphor-yl)ferrocen-yl]meth-yl}dimethyl-ammonium diphenyl-dithio-phosphinate  

PubMed Central

2-(Diphenyl­thio­phosphino)dimethyl­amino­methyl­ferrocene is a key inter­mediate in the synthesis of various ferrocenyl ligands. During one such synthesis, the title compound, [Fe(C5H5)(C20H22NPS)](C12H10PS2), was isolated as a by-product. It is built up by association of (2-(diphenyl­phosphino)ferrocen­yl)meth­yl)dimethyl­ammonium cations and diphenyl­phosphino dithio­ate anions. N—H?S, C—H?S and C—H?? inter­actions link the anions and cations. Each anion–cation pair is linked two by two through C—H?? inter­actions, forming pseudo dimers.

Mouas, Nardjes; Merazig, Hocine; Daran, Jean-Claude; Manoury, Eric

2012-01-01

432

Nonlinear optical absorption and fluorescence of phosphine-substituted bithiophenes in the violet-blue spectral region  

NASA Astrophysics Data System (ADS)

The nonlinear optical absorptions of two 5,5?-bis(diphenylphosphino)-2,2?-bithiophene derivatives, Ph2(X)P(C4H2S)2P(X)Ph2 (X = O, 1; S, 2), have been investigated by direct transmission measurement with both picosecond and nanosecond laser pulses from 420 nm to 480 nm. Saturated dichloromethane solutions of 1 and 2 exhibit strong nonlinear optical absorptions in this violet-blue spectral region with that of 2 being stronger at all wavelengths. In the picosecond regime, at 420 nm, the transmittance rapidly falls to 50% when the incident fluence is 0.22 J/cm2 for 1 and 0.11 J/cm2 for 2. Two-photon absorption appears to be the primary mechanism for this nonlinear absorption. The two-photon absorption coefficients ? for 1 (2.1 cm/GW) and 2 (4.4 cm/GM) were obtained by fitting the measurement of transmittance as the function of incident beam intensity at 420 nm. These ? values are comparable with some of the best results obtained for organic materials in the green, red and infrared spectral region. Both compounds also show fluorescence with an emission peak at 390 nm for 1 and 400 nm for 2. The fluorescence of 1 is considerably stronger than is that of 2. The combination of the wide band gap and strong fluorescence emission of 1 makes it a promising candidate as a host material for blue organic light emitting diodes.

Wang, Jianwei; Zhao, Qun; Lawson, Christopher M.; Gray, Gary M.

2011-06-01

433

Phosphine-containing carbosilane dendrimers based on polyhedral silsesquioxane cores as ligands for hydroformylation reaction of oct-1-ene  

Microsoft Academic Search

Radical additions of diethyl- and diphenylphosphine have been used to prepare 1st and 2nd generation dendrimers based on polyhedral oligosilsesquioxane cores by a divergent synthetic method. The 1st generation dendrimer is built on either 16 and 24 vinyl or allyl arms formed by successive hydrosilation and vinylation or allylation of vinyl-functionalised polyhedral silsesquioxanes. Successive hydrosilation\\/allylation followed by hydrosilation\\/vinylation and addition

Russell E. Morris; Douglas F. Foster; David J. Cole-Hamilton

2002-01-01

434

Novel anionic phosphine transition metal hydride complexes and their application to the catalytic hydrogenation of polar organic compounds  

SciTech Connect

Potassium tris(triphenylphosphine) ruthenium hydride complexed with diethyl ether and naphthalene was an effective homogeneous catalyst in the hydrogenation, under mild conditions (85/sup 0/-90/sup 0/C and 620 kPa hydrogen), of acetone to isopropanol, propanol to n-propanol, acrolein to allyl alcohol (and propionaldehyde), activated carboxylic acid esters, e.g., methyl trifluoroacetate and dimethyl oxalate, to corresponding alcohols, and acetonitrile to ethylamine. In most reactions, the selectivity for the hydrogenated products was above 90 per cent.

Grey, R.A.; Pez, G.P.

1980-01-01

435

Metal–Polymer Hybrid Material as a Catalyst for the Heck Coupling Reaction Under Phosphine-Free Conditions  

Microsoft Academic Search

A method is described for making a poly-aminophenol-based hybrid material by in situ polymerization of aminophenol using palladium acetate as the oxidant. The oxidative polymerization of aminophenol leads to the formation of poly-aminophenol, while the reduction of palladium acetate results in the formation of palladium nanoparticles. The palladium nanoparticles were found to be highly dispersed and stabilized throughout the polymer

Rafique Ul Islam; Michael J. Witcomb; Michael S. Scurrell; Willem van Otterlo; Elma van der Lingen; Kaushik Mallick

2011-01-01

436

Metal-polymer Hybrid Material as a Catalyst for the Heck Coupling Reaction Under Phosphine Free Conditions  

Microsoft Academic Search

A method is described for making a poly-aminophenol based hybrid material by in-situ polymerization of aminophenol using palladium acetate as the oxidant. The oxidative polymerization of aminophenol leads to the formation of poly-aminophenol, while the reduction of palladium acetate results in the formation of palladium nanoparticles. The palladium nanoparticles were found to be highly dispersed and stabilized throughout the polymer

Rafique Ul Islam; Michael J. Witcomb; Michael S. Scurrell; Willem Van Otterlo; Elma van der Lingen; Kaushik Mallick

2011-01-01

437

Bis(?2-ethyl-ene)[aza-nidediylbis(diiso-propyl-phosphine selenide)-?2 Se,Se?]iridium(III)  

PubMed Central

In the title compound, [Ir(?2-C2H4)2(C12H28NP2Se2)], the central Ir atom is chelated by the [N(iPr2PSe)2]? ligand via two Se atoms and is coordinated by two ?2-ethyl­ene mol­ecules via four C atoms in an octa­hedral coordination geometry.

Wu, Fang-Hui; Lu, Lude; Duan, Taike; Zhang, Qian-Feng

2009-01-01

438

Catalytic expoxidation of propylene by isopropylbenzene hydroperoxide in the presence of complexes of molybdenum with phosphine, arsine, and stibine ligands  

SciTech Connect

The catalytic activity of complexes of molybdenum - derivatives of Mo(CO)/sub 6/, containing triphenylphosphine, -arsine, and -stilbine ligands - in the epoxidation of propylene by isopropylbenzene was studied. It was shown that the activity and selectivity of molybdenum complexes depends on the nature of the ligand surroundings of the molybdenum atom.

Leonov, V.N.; Belyi, A.A.; Ginzborg, A.G.; Strozhkova, G.A.; Ustynyuk, N.A.

1985-07-01

439

Selective C-F/C-H bond activation of fluoroarenes by cobalt complex supported with phosphine ligands.  

PubMed

The reactions of pentafluoropyridine C5NF5, hexafluorobenzene C6F6, and perfluoronaphthalene C10F8 with cobalt(0) complex, Co(PMe3)4, were investigated. The Co(I) complexes (4-C5NF4)Co(PMe3)3 (1), (C6F5)Co(PMe3)3 (2), (C10F7)Co(PMe3)3 (3), (4-C5NF4)Co(PMe3)4 (4) and (C10F7)Co(PMe3)4 (6) were obtained by selective activation of the C–F bonds. The reactions of 1 and 2 with CO afforded dicarbonyl cobalt(I) complexes (4-C5NF4)Co(CO)2(PMe3)2 (7), (C6F5)Co(CO)2(PMe3)2 (8). Under similar reaction conditions, 2 as a C–H bond activation product was obtained from the reaction of pentafluorobenzene, C6F5H, with Co(PMe3)4. The byproducts, hydrodefluorination product 1,2,4,5-C6F4H2 and F2PMe3 from the reaction of C6F5H and Co(PMe3)4 were also observed. The reaction mechanism of C6F5H with Co(PMe3)4 is proposed and partly-experimentally verified. The reaction of C6F5H with Co(PMe3)4 under 1 bar of CO at room temperature afforded hydrido dicarbonyl cobalt(II) complex (C6F5)Co(H)(CO)2(PMe3)2 (11). Treatment of the mixtures of C6F5H/Co(PMe3)4 with hexachlorobenzene, C6Cl6, resulted in (C6F5)CoCl(PMe3)3 (12) via C–H bond cleavage with the hydrodechlorination product pentachlorobenzene, C6Cl5H, and 1,2,4,5-tetrachlorobenzene, C6Cl4H2. The structures of complexes 1, 2, 6, 7, 8, 11 and 12 were determined by X-ray diffraction. PMID:23450256

Li, Junye; Zheng, Tingting; Sun, Hongjian; Xu, Wengang; Li, Xiaoyan

2013-04-28

440

Synthesis, structures and photophysical properties of polynuclear copper(I) iodide complexes containing phosphine and 4,4?-bipyridine ligands  

Microsoft Academic Search

The highly luminescent polynuclear CuI iodide complexes, [(Cu2I2)(4,4?-bipy)(PCy3)2]2·4H2O (1), [(Cu2I2)(4,4?-bipy)(PCy3)2]? (2), [(Cu2I2)(4,4?-bipy)(dcpm)]? (3) and [(Cu2I2)(4,4?-bipy)(dppm)]? (4), were prepared by reacting CuI with tricyclohexylphosphine (PCy3), bis(dicyclohexylphosphino)methane (dcpm) or bis(diphenylphosphino)methane (dppm) and 4,4?-bipyridine (4,4?-bipy), and their structures were determined by X-ray crystal analysis. The reported complexes [CuClPCy3]2 (5) and [CuIPCy3]2 (6) were also prepared for comparison. In solid state, complexes 1–6 display

Xin Gan; Wen-Fu Fu; Yong-Yue Lin; Mei Yuan; Chi-Ming Che; Shao-Ming Chi; Hui-Fang Jie Li; Jian-Hua Chen; Yong Chen; Zhong-Yong Zhou

2008-01-01

441

Mössbauer spectra of Eu(III) and Gd(III) complexes of phosphine oxides with chelating perchlorate  

NASA Astrophysics Data System (ADS)

The reaction of Ln(ClO4)3· nH2O with triphenylphosphine oxide (TPPO) in methanol has led to the formation of [Ln(ClO4)2(tppo)4]ClO4·MeOH (Ln = Nd, Eu, Gd, Dy, Yb), in which the perchlorate anion acts as a symmetric bidentate. The emission spectra of Eu(III)-TPPO complexes, showing enhancement in the intensity due to the phenyl group, indicate an isotropic electron distribution for the nitrato complex [Eu(NO3)3(tppo)2(EtOH)]. 151Eu and 155Gd Mössbauer spectra of the TPPO complexes also lead to the same conclusion.

Takahashi, Masashi; Hirai, Yuya

2012-03-01

442

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

SciTech Connect

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

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

2009-06-01

443

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

NASA Astrophysics Data System (ADS)

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

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

2009-12-01

444

Synthesis, characterization and structural determination of some nickel(II) complexes containing imido Schiff bases and substituted phosphine ligands  

NASA Astrophysics Data System (ADS)

Some new tridentate ONN Schiff base complexes of [NiL(PR3)] (where L = Salicylidene2-amino4-nitrobenzene (L1), 5-BrSalicylidene2-amino4-nitrobenzene (L2), 5-NO2Salicylidene2-amino4-nitrobenzene (L3), 5-MeOSalicylidene2-amino4-nitrobenzene (L4) and 3-MeOSalicylidene2-amino4-nitrobenzene (L5), R = Bu and Ph (with L1)) were synthesised and characterized by IR, UV-Vis, 1H NMR spectroscopy and elemental analysis. The geometry of [NiL1(PPh3)] was determined by X-ray crystallography. It indicated that the complex had a planar structure and four coordinates in the solid state. The thermogravimetry (TG) and differential thermoanalysis (DTA) of the synthesized complexes were carried out in the range of 20-600 °C, leading to the decomposition of L1-L3 type in three stages and of L4-L5 and [NiL1(PPh3)] type in four stages. Thermal decomposition of the complexes was closely the dependent upon the nature of the Schiff base ligands and proceeded via the first order kinetics.

Kianfar, Ali Hossein; Ebrahimi, Mostafa

2013-11-01

445

Process for Treating Cotton Textiles with n,N '-Ethylene Bis(P,P-Bis (Aziridinyl)-NMETHYL Phosphinic Amide).  

National Technical Information Service (NTIS)

The invention involves process for treating cotton textile material and inducing therein dimensional stability, wrinkle resistance, and flame resistance; which process comprises impregnating the cotton textile material with an aqueous solution of N,N'ethy...

L. H. Chance

1965-01-01

446

Organoactinide phosphine/phosphite coordination chemistry. Facile hydride-induced dealkoxylation and the formation of actinide phosphinidene complexes  

SciTech Connect

A study of the reaction of the organoactinide hydrides (Cp'/sub 2/MH/sub 2/)/sub 2/ (Cp' = eta/sup 5/-(CH/sub 3/)/sub 5/C/sub 5/, M = Th, U) with trimethyl phosphite is reported. Quantitative transposition of hydride and methoxide ligands occurs to yield the corresponding Cp'/sub 2/M(OCH/sub 3/)/sub 2/ complexes (synthesized independently from Cp'/sub 2/MCl/sub 2/ and NaOCH/sub 3/) and the phosphinidene-bridged methoxy complexes (Cp'/sub 2/M(OCH/sub 3/))/sub 2/PH. The reaction is considerably more rapid for M = U than for M = Th. The new compounds were characterized by elemental analysis, /sup 1/H and /sup 31/P NMR, infrared spectroscopy, magnetic susceptibility, and D/sub 2/O hydrolysis. The molecular structure of (Cp'/sub 2/U(OCH/sub 3/))/sub 2/PH has been determined by single-crystal X-ray diffraction techniques. It crystallizes in the monoclinic space group P2/n with a = 13.926 (3) A, b = 10.765 (3) c = 15.282 (4) A, ..beta.. = 107.63 (2)/sup 0/, and Z = 2. Full-matrix least-squares refinement of the structural parameters for the 24 independent anisotropic non-hydrogen atoms has converged to R/sub 1/ (unweighted, based on F) = 0.041 for 1677 independent absorption-corrected reflections having 2 theta/sub MoK..cap alpha../ < 43/sup 0/ and I > 3sigma(I). The (Cp'/sub 2/U(OCH/sub 3/))/sub 2/PH molecule has C/sub 2/ symmetry, with the ..mu..-PH/sup 2 -/ ligand lying on a crystallographic twofold axis. The coordination geometry about each uranium ion is of the typical pseudotetrahedral Cp'/sub 2/M(X)T type, with U-P = 2.743 (1) A, U-O = 2.046 (14) A, angle U-P-U = 157.7 (2)/sup 0/, and angle U-O-C (methyl) = 178 (1)/sup 0/. Evidence is presented that other > P-OR linkages react in a similar manner.

Duttera, M.R.; Day, V.W.; Marks, T.J.

1984-05-16

447

Slow-onset inhibition of fumarylacetoacetate hydrolase by phosphinate mimics of the tetrahedral intermediate: kinetics, crystal structure and pharmacokinetics  

PubMed Central

FAH (fumarylacetoacetate hydrolase) catalyses the final step of tyrosine catabolism to produce fumarate and acetoacetate. HT1 (hereditary tyrosinaemia type 1) results from deficiency of this enzyme. Previously, we prepared a partial mimic of the putative tetrahedral intermediate in the reaction catalysed by FAH co-crystallized with the enzyme to reveal details of the mechanism [Bateman, Bhanumoorthy, Witte, McClard, Grompe and Timm (2001) J. Biol. Chem. 276, 15284–15291]. We have now successfully synthesized complete mimics CEHPOBA {4-[(2-carboxyethyl)-hydroxyphosphinyl]-3-oxobutyrate} and COPHPAA {3-[(3-carboxy-2-oxopropyl)hydroxyphosphinyl]acrylate}, which inhibit FAH in slow-onset tight-binding mode with Ki values of 41 and 12 nM respectively. A high-resolution (1.35 Å; 1 Å=0.1 nm) crystal structure of the FAH·CEHPOBA complex was solved to reveal the affinity determinants for these compounds and to provide further insight into the mechanism of FAH catalysis. These compounds are active in vivo, and CEHPOBA demonstrated a notable dose-dependent increase in SA (succinylacetone; a metabolite seen in patients with HT1) in mouse serum after repeated injections, and, following a single injection (1 ?mol/g; intraperitoneal), only a modest regain of FAH enzyme activity was detected in liver protein isolates after 24 h. These potent inhibitors provide a means to chemically phenocopy the metabolic defects of either HT1 or FAH knockout mice and promise future pharmacological utility for hepatocyte transplantation.

Bateman, Raynard L.; Ashworth, Justin; Witte, John F.; Baker, L.-J.; Bhanumoorthy, Pullooru; Timm, David E.; Hurley, Thomas D.; Grompe, Markus; Mcclard, Ronald W.

2006-01-01

448

Study of the phosphine plasma decomposition and its formation by ablation of red phosphorus in hydrogen plasma  

Microsoft Academic Search

Mass spectrometry and optical emission spectroscopy have been used to study the chemistry of PH(sub 3) plasma decomposition as well as its formation by ablation of red phosphorus in hydrogen plasma. It has been shown that PH(sub 3) decomposition easily equilibrates at low levels of PH(sub 3) depletion (15%-30%), this depending mainly on the rf power. The ablation of red

G. Bruno; M. Losurdo; P. Capezzuto

1995-01-01

449

Latitudinal Distribution of Ammonia and Upper Limits of Acetylene and Phosphine in Jupiter's Upper Troposphere and Lower Stratosphere  

Microsoft Academic Search

Observations of the northern and southern hemispheres of Jupiter done with the Hubble Space Telescope Faint Object Spectrograph during May 19-25, 1992 and June 6, 1993 have been analyzed. Spectra at latitudes 6deg N, 15deg N, 20deg N, 25deg N, 48deg N, 65deg N, 12deg S, 25deg S, 33deg S, 48deg S, 65deg S, and the equator were taken along

S. G. Edgington; S. K. Atreya; L. M. Trafton; J. J. Caldwell; R. F. Beebe; A. A. Simon; R. A. West; C. Barnet

1996-01-01

450

Facile synthesis of uniform large-sized InP nanocrystal quantum dots using tris(tert-butyldimethylsilyl)phosphine  

PubMed Central

Colloidal III-V semiconductor nanocrystal quantum dots [NQDs] have attracted interest because they have reduced toxicity compared with II-VI compounds. However, the study and application of III-V semiconductor nanocrystals are limited by difficulties in their synthesis. In particular, it is difficult to control nucleation because the molecular bonds in III-V semiconductors are highly covalent. A synthetic approach of InP NQDs was presented using newly synthesized organometallic phosphorus [P] precursors with different functional moieties while preserving the P-Si bond. Introducing bulky side chains in our study improved the stability while facilitating InP formation with strong confinement at a readily low temperature regime (210°C to 300°C). Further shell coating with ZnS resulted in highly luminescent core-shell materials. The design and synthesis of P precursors for high-quality InP NQDs were conducted for the first time, and we were able to control the nucleation by varying the reactivity of P precursors, therefore achieving uniform large-sized InP NQDs. This opens the way for the large-scale production of high-quality Cd-free nanocrystal quantum dots.

2012-01-01

451

Phosphorescent Ir(III) complexes with both cyclometalate chromophores and phosphine-silanolate ancillary: concurrent conversion of organosilane to silanolate.  

PubMed

Ir(III) metal complexes with general formula [(C^N)2Ir(P^SiO)], where (C^N)H is 2-phenylisoquinoline (1), 2-phenylpyridine (2) or 2-(2,4-difluorophenyl)pyridine (3), and (P^SiO)H is an organosilanolate ancillary chelate with either diphenylsilyl (a) or dimethylsilyl (b) substituent, were synthesized, among which the structure of 3a was also confirmed using single-crystal X-ray diffraction analyses. These complexes exhibit bright phosphorescence in the region of 489-632 nm in solution at room temperature, showing the first successful example of using organosilanolate as an ancillary chelate. For application, organic light emitting diodes (OLEDs) using phosphors 3a and 3b doped in N,N'-dicarbazolyl-3,5-benzene (mCP) exhibited a maximum brightness of 50,800 cd m(-2) at 800 mA cm(-2) (12 V) with ?(ext) of 10.1% and a brightness of 45,900 cd m(-2) at 700 mA cm(-2) (14.5 V) with ?(ext) of 10.2%, respectively. PMID:23518610

Zhang, Fushi; Wang, Liduo; Chang, Shih-Han; Huang, Kuan-Lin; Chi, Yun; Hung, Wen-Yi; Chen, Chih-Ming; Lee, Gene-Hsiang; Chou, Pi-Tai

2013-05-21

452

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

PubMed

Interaction of octyl-phenyl-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO, the 'classical' rare metal extraction agent) with fully ionized hydrated protons (HP) was studied in acetonitrile-d(3) using (1)H, (13)C, (31)P NMR, PFG NMR and magnetic relaxation. The experimental results were confronted with high-precision ab initio DFT calculations. Relative chemical shifts of NMR signals of CMPO (0.01 mol/L) under the presence of HP in the molar ratio ? = 0-2.0 mol/mol show binding between CMPO and HP. Self-diffusion measurements using (1)H PFG NMR demonstrate that larger complexes with higher content of CMPO are generally formed at ? < 0.75. Analyzing the collective dependence of (13)C and (31)P NMR chemical shifts on ? by the use of program LETAGROP, we obtained very good fitting for the assumed coexistence of two complexes (CMPO)(2)·HP (C(2)) and CMPO.HP (C(1)). The logarithms of the respective stabilization constants log K(i) were found to be 7.518 (C(2)) and 4.581 (C(1)). The system dynamics was studied by measuring the transverse (1)H NMR relaxation using CPMG sequence with varying delays t(p) between the ? pulses in the mixtures with ? = 0.4-0.8. The following exchange correlation times were obtained: ?(10) = 2.35 × 10(-5), ?(20) = 0.82 × 10(-4), ?(21) = 0.45 × 10(-3) s. The DFT calculations support the conclusion that the complexes C(1) and C(2) are the main species in the mixtures of CMPO with HP. They also agree with the NMR and FTIR observation that the main site to which H(3) O(+) is bound is the P=O group, whereas the amide group does not form a strong bond with the ion when excess water molecules are present. PMID:21898583

K?íž, Jaroslav; Dybal, Ji?í; Makrlík, Emanuel; Va?ura, Petr

2011-09-06

453

Stepwise 1D growth of luminescent Au(I)-Ag(I) phosphine-alkynyl clusters: synthesis, photophysical, and theoretical studies.  

PubMed

Reactions between the diphosphino-gold cationic complexes [Au(2)(PPh(2)-C(2)-(C(6)H(4))(n)-C(2)-PPh(2))(2)](2+) (n = 0, 1, 2, 3) and polymeric acetylides (AuC(2)Ph)(n) and (AgC(2)Ph)(n) lead to the formation of a new family of heterometallic clusters with the general formula [Au(8+2n)Ag(6+2n)(C(2)Ph)(8+4n)(PPh(2)C(2)(C(6)H(4))(n)C(2)PPh(2))(2)](2+), n = 0 (1), 1 (2), 2 (3), 3 (4). Compounds 1-4 were characterized in detail by NMR and ESI-MS spectroscopy. Complex 1 (n = 0) crystallizes in two forms (orange (1a) and yellow (1b)), one of which (1a) has been analyzed by X-ray crystallography. The luminescence behavior of 1-4 has been studied. Compounds 2 and 3 exhibited orange-red phosphorescence with quantitative quantum efficiency in both aerated and degassed CH(2)Cl(2), implying O(2)-independent phosphorescence due to efficient protection of the emitting chromophore center by the organic ligands. Complex 3 exhibits reasonable two-photon absorption (TPA) property with a cross section of ? ? 45 GM (800 nm), which is comparable to the value of commercially available TPA dyes such as coumarin 151. Computational studies have been performed to correlate the structural and photophysical features of the complexes studied. The metal-centered triplet emission within the heterometallic core is suggested to play a key role in the observed phosphorescence. The luminescence spectrum of 1 in CH(2)Cl(2) shows dual phosphorescence maximized at 575 nm (the P(1) band) and 770 nm (the P(2) band). Both P(1) and P(2) bands possess identical excitation spectra, i.e., the same ground-state origin, and the same relaxation dynamics throughout the temperature range of 298-200 K. The dual emission of 1 arises from fast structural fluctuation upon excitation, perhaps forming two geometry isomers, which exhibit distinctly different P(1) and P(2) bands. The scrambling dynamics might require large-amplitude motion and, hence, is hampered in rigid media, as evidenced by the single emission for 1a (610 nm) and 1b (570 nm) observed in solid. PMID:21302906

Koshevoy, Igor O; Lin, Chia-Li; Karttunen, Antti J; Jänis, Janne; Haukka, Matti; Tunik, Sergey P; Chou, Pi-Tai; Pakkanen, Tapani A

2011-02-08

454

Slow-onset inhibition of fumarylacetoacetate hydrolase by phosphinate mimics of the tetrahedral intermediate: kinetics, crystal structure and pharmacokinetics.  

PubMed

FAH (fumarylacetoacetate hydrolase) catalyses the final step of tyrosine catabolism to produce fumarate and acetoacetate. HT1 (hereditary tyrosinaemia type 1) results from deficiency of this enzyme. Previously, we prepared a partial mimic of the putative tetrahedral intermediate in the reaction catalysed by FAH co-crystallized with the enzyme to reveal details of the mechanism [Bateman, Bhanumoorthy, Witte, McClard, Grompe and Timm (2001) J. Biol. Chem. 276, 15284-15291]. We have now successfully synthesized complete mimics CEHPOBA {4-[(2-carboxyethyl)-hydroxyphosphinyl]-3-oxobutyrate} and COPHPAA {3-[(3-carboxy-2-oxopropyl)hydroxyphosphinyl]acrylate}, which inhibit FAH in slow-onset tight-binding mode with K(i) values of 41 and 12 nM respectively. A high-resolution (1.35 A; 1 A=0.1 nm) crystal structure of the FAH.CEHPOBA complex was solved to reveal the affinity determinants for these compounds and to provide further insight into the mechanism of FAH catalysis. These compounds are active in vivo, and CEHPOBA demonstrated a notable dose-dependent increase in SA (succinylacetone; a metabolite seen in patients with HT1) in mouse serum after repeated injections, and, following a single injection (1 mumol/g; intraperitoneal), only a modest regain of FAH enzyme activity was detected in liver protein isolates after 24 h. These potent inhibitors provide a means to chemically phenocopy the metabolic defects of either HT1 or FAH knockout mice and promise future pharmacological utility for hepatocyte transplantation. PMID:17064256

Bateman, Raynard L; Ashworth, Justin; Witte, John F; Baker, L-J; Bhanumoorthy, Pullooru; Timm, David E; Hurley, Thomas D; Grompe, Markus; McClard, Ronald W

2007-03-01

455

The nucleophilic, phosphine-catalyzed thiol–ene click reaction and convergent star synthesis with RAFT-prepared homopolymers  

Microsoft Academic Search

The synthesis of 3-arm star polymers from reversible addition–fragmentation chain transfer (RAFT)-prepared precursor homopolymers in combination with thiol–ene click chemistry is described. Homopolymers of n-butyl acrylate and N,N-diethylacrylamide were prepared with 1-cyano-1-methylethyl dithiobenzoate and 2,2?-azobis(2-methylpropionitrile) yielding materials with polydispersity indices (Mw\\/Mn)?1.18 and controlled molecular weights as determined by a combination of NMR spectroscopy, size exclusion chromatography (SEC), and matrix assisted

Justin W. Chan; Bing Yu; Charles E. Hoyle; Andrew B. Lowe

2009-01-01

456

Extraction from HNO{sub 3} solutions and separation of Pu(IV) from Am(III) by diphenyl(dialkyl carbamoylmethyl)phosphine oxides  

SciTech Connect

Five carbamoylmethylphosphine oxide (CMPO) extractants with phenyl substituents on the P atom and alkyl groups (butyl, octyl, isoamyl) or cyclic hydrocarbons (piperidine, morpholine) on the N atom are used to study the extraction of Pu(IV) from HNO{sub 3} solutions by CMPO in a polar aromatic fluorinated diluent as a function of [HNO{sub 3}] and [CMPO]. All studied CMPOs quantitatively extract Pu(IV) from HNO{sub 3} with distribution coefficients that are 2-3 orders of magnitude greater than those of Am(III). The elements Pu and Am can be separated during back-extraction.

Litvina, M.N.; Chmutova, M.K.; Nesterova, N.P. [V.I. Vernadskii Institute of Geochemistry and Analytical Chemistry, Moscow (Russian Federation)] [and others

1995-03-01

457

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

NASA Astrophysics Data System (ADS)

: 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.

Clavier, Herve; Nolan, Steven P.

458

Oxidative quenching within photosensitizer-acceptor dyads based on bis(bidentate) phosphine-connected osmium(II) bipyridyl light absorbers and reactive metal sites.  

PubMed

For the first time oxidative quenching of OsP2N4 chromophores by reactive Pt(II) or Pd(II) sites containing cis, trans, cis-1,2,3,4-tetrakis(diphenylphosphino)cyclobutane (dppcb) is directly observed despite the presence of a saturated cyclobutane backbone "bridge". This dramatic effect is measured as a sudden temperature-dependent onset of a reduction in phosphorescence lifetime in [Os(bpy)2(dppcb)MCl2](SbF6)2 (M = Pt, 1; Pd, 2). The appearance of this additional energy release is not detectable in [Os(bpy)2(dppcbO2)](PF6)2 (3), where dppcbO2 is cis, trans, cis-1,2-bis(diphenylphosphinoyl)-3,4-bis(diphenylphosphino)cyclobutane. Obviously, the square-planar metal centers in 1 and 2 are responsible for this effect. In line with these observations, the emission quantum yields at room temperature for 1 and 2 are drastically reduced compared with 3. Since this luminescence quenching implies strong intramolecular interaction between the Os(II) excited states and the acceptor sites and depends on the metal?metal distances, also the single crystal X-ray structures of 1-3 are given. PMID:23471298

Eller, Sylvia; Trettenbrein, Barbara; Oberhuber, Dennis; Strabler, Christof; Gutmann, Rene; van der Veer, Wytze E; Ruetz, Markus; Kopacka, Holger; Obendorf, Dagmar; Brüggeller, Peter

2012-09-01

459

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

Microsoft Academic Search

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

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

2007-01-01