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1

Mechanisms of Phosphine Toxicity  

PubMed Central

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

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

2011-01-01

2

[Occupational phosphine poisoning].  

PubMed

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

Kurzbauer, H; Kiesler, A

1987-01-01

3

Phosphonate–Phosphinate Rearrangement  

PubMed Central

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

2014-01-01

4

HUMAN GENOTOXICITY: PESTICIDE APPLICANTS AND PHOSPHINE  

EPA Science Inventory

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

5

[Phosphine poisoning in healthcare workers].  

PubMed

Phosphine gas constitutes a potential and serious little-known cause of poisoning of professional nature of the medical staff and nursing care of patients who voluntarily swallow phosphides rodenticides purposes suicide. The objective of this paper is to inform to healthcare workers from urgencies, forensic and occupational health services on this occupational hazard. We present the case of a nurse who suffered from poisoning by gas phosphine confirmed through an environmental monitoring of gases in an emergency department carried out by the government service of civil protection of the State of Jalisco. PMID:21894233

Arredondo Trujillo, Francisco; Hurtado Pérez, Martha Patricia; Castañeda Borrayo, Yaocihuatl

2011-01-01

6

Chiral phosphines in nucleophilic organocatalysis  

PubMed Central

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

Xiao, Yumei; Sun, Zhanhu

2014-01-01

7

Human genotoxicity: pesticide applicators and phosphine.  

PubMed

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. Less stable aberrations including chromatid deletions and gaps were significantly increased only during the application season, but not at this later time point. During fumigant application, measured exposure to phosphine exceeds accepted national standards. Because phosphine is also used as a dopant in the microchip industry and is generated in waste treatment, the possibility of more widespread exposure and long-term health sequelae must be considered. PMID:2799386

Garry, V F; Griffith, J; Danzl, T J; Nelson, R L; Whorton, E B; Krueger, L A; Cervenka, J

1989-10-13

8

Phosphine photochemistry in Saturn's atmosphere  

NASA Technical Reports Server (NTRS)

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.

1983-01-01

9

7 CFR 305.7 - Phosphine treatment schedules.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 2010-01-01 false Phosphine treatment schedules. 305.7 Section 305.7 Agriculture...SERVICE, DEPARTMENT OF AGRICULTURE PHYTOSANITARY TREATMENTS Chemical Treatments § 305.7 Phosphine treatment...

2010-01-01

10

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

Code of Federal Regulations, 2011 CFR

...2011-07-01 false Substituted alkyl phosphine oxide (generic). 721.10087 Section 721...721.10087 Substituted alkyl phosphine oxide (generic). (a) Chemical substance...generically as substituted alkyl phosphine oxide (PMN P-06-332) is subject to...

2011-07-01

11

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

Code of Federal Regulations, 2012 CFR

...2012-07-01 false Substituted alkyl phosphine oxide (generic). 721.10087 Section 721...721.10087 Substituted alkyl phosphine oxide (generic). (a) Chemical substance...generically as substituted alkyl phosphine oxide (PMN P-06-332) is subject to...

2012-07-01

12

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

PubMed

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

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

2012-02-17

13

Serial blood phosphine levels in acute aluminium phosphide poisoning.  

PubMed

Serial blood phosphine (PH3) levels were done in patients with severe (Group I, n = 30), mild (Group 2, n = 10) and minimal or nil toxicity due to aluminium phosphide compound. Blood phosphine levels were significantly higher (p < 0.001) in patients of Group I than other two groups. Phosphine was not detectable in Group 3 patients. Therefore, blood phosphine levels were positively correlated to clinical grades of toxicity and to dose of active pesticide consumed. Higher the blood phosphine, higher was the mortality. Patients having blood phosphine levels equal to or less than 1.067 +/- 0.16 mg% survived, hence, it appeared to be limit of phosphine toxicity. PMID:9251315

Chugh, S N; Pal, R; Singh, V; Seth, S

1996-03-01

14

Liver histopathology of fatal phosphine poisoning.  

PubMed

Two commonly used pesticides in agriculture are phosphides of aluminium and zinc. Both of these metal phosphides act through elaboration of toxic phosphine gas. The poisoning in Iran is mostly oral and suicidal. Phosphine is rapidly absorbed throughout the gastrointestinal tract after ingestion and it is partly carried to the liver by the portal vein. In this study the liver histopathology of fatal poisoning is scrutinized. A descriptive, retrospective study was performed on 38 fatal phosphine poisonings. The slides of liver specimens of the cases were retrieved and studied separately by two pathologists. The poisoning was suicidal in 33 (86.5%) of cases. Portal inflammation was negligible in 37 cases and only in one of the cases, a moderate degree of chronic inflammation accompanied by granuloma formation was observed. Major histopathologic findings were as follows: mild sinusoidal congestion; 12 cases (31.6%), severe sinusoidal congestion; 25 cases (45.8%), central vein congestion; 23 cases (60.5%), centrilobular necrosis; 3 cases (7.9%), hepatocytes nuclear fragmentation; 6 cases (15.8%), sinusoidal clusters of polymorphonuclear leukocytes; 12 cases (31.6%), and mild macrovesicular steatosis; 5 cases (13.2%). Fine isomorphic cytoplasmic vacuoles were observed in 36 cases (94.7%). These vacuoles were distributed uniformly in all hepatic zones in the majority (75%) of cases. This study reveals that the main histopathologic findings of fatal phosphine poisoning in the liver are fine cytoplasmic vacuolization of hepatocytes and sinusoidal congestion. PMID:16806774

Saleki, Sepideh; Ardalan, Farid Azmoudeh; Javidan-Nejad, Abdullah

2007-03-01

15

Palladium-Catalyzed ?-Arylation of Benzylic Phosphine Oxides  

PubMed Central

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

Montel, Sonia; Jia, Tiezheng

2014-01-01

16

Preparation of phosphines through C–P bond formation  

PubMed Central

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

Wauters, Iris; Debrouwer, Wouter

2014-01-01

17

Disruption of Iron Homeostasis Increases Phosphine Toxicity in Caenorhabditis elegans  

E-print Network

Disruption of Iron Homeostasis Increases Phosphine Toxicity in Caenorhabditis elegans Ubon Cha-dependent actions of phosphine, in vitro: (1) reduction of ferric iron (Fe3+ ) to ferrous iron (Fe2+ ), (2) release of iron from horse ferritin, (3) and the peroxidation of lipid as a result of iron release from ferritin

Hammock, Bruce D.

18

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

PubMed

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

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

2015-02-01

19

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. PMID:23300916

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

2012-01-01

20

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

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

2013-11-01

21

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

22

40 CFR 180.225 - Phosphine; tolerances for residues.  

Code of Federal Regulations, 2010 CFR

... false Phosphine; tolerances for residues. 180.225 Section 180.225...ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Specific Tolerances §...

2010-07-01

23

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

24

Transition metal complexes of a novel tetradentate phosphine and of a new diphosphine ether.  

E-print Network

??This dissertation describes the synthesis and coordination chemistry of two new phosphine ligands and a novel fluoride-induced redox reaction. The tetratertiary phosphine 2,3-bis(diphenylphosphinomethyl)-1,4-bis(diphenylphosphino)butane (1) coordinates… (more)

Mason, Mark R.

1991-01-01

25

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

E-print Network

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

Hirai, Satoko

2005-01-01

26

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

Code of Federal Regulations, 2012 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...

2012-07-01

27

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

28

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

Code of Federal Regulations, 2010 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...

2010-07-01

29

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

...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...

2014-07-01

30

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

Code of Federal Regulations, 2011 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...

2011-07-01

31

Phosphine generation by mixed- and monoseptic-cultures of anaerobic bacteria  

Microsoft Academic Search

A microbial basis for bioreductive generation of phosphine is proposed, which could account at least in part for the presence of this toxic gas in natural anaerobic environments and in sewage and landfill gases. Phosphine generation under anaerobic growth conditions was dependent upon both the culture inoculum source (animal faeces) and enrichment culture conditions. Phosphine was detected in headspace gases

R. o. Jenkins; T.-A. Morris; P. j. Craig; A. w. Ritchie; N. Ostah

2000-01-01

32

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

PubMed Central

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

Valmas, Nicholas; Ebert, Paul R.

2006-01-01

33

Unintentional poisoning by phosphine released from aluminum phosphide.  

PubMed

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

Shadnia, S; Mehrpour, O; Abdollahi, M

2008-01-01

34

Trichloridobis(ethyl­diphenyl­phosphine)(tetra­hydro­furan)­molybdenum(III)  

PubMed Central

In the mononuclear title compound, [MoCl3(C4H8O)(C14H15P)2], obtained by the reaction of trichloro­tris­(tetra­hydro­furan)­molybdenum(III) and ethyl­diphenyl­phosphine in tetra­hydro­furan (THF) solution, the MoIII atom is six-coordinated by one O atom of a THF mol­ecule, two P atoms from two ethyl­diphenyl­phosphine ligands and three Cl atoms in a distorted octa­hedral geometry. The C atoms of the THF molecule are disordered over two positions in a 0.55?(2):0.45?(2) ratio. PMID:21587711

Kruczy?ski, Tomasz; Pikies, Jerzy; Ponikiewski, ?ukasz

2010-01-01

35

Dipole moments and conformational analysis of tris(2-pyridyl)phosphine and tris(2-pyridyl)phosphine chalcogenides. Experimental and theoretical study  

NASA Astrophysics Data System (ADS)

Conformational analysis of tris(2-pyridyl)phosphine and tris(2-pyridyl)phosphine chalcogenides was carried out by the method of dipole moments and density functional theory calculations. The conformations of the examined compounds fit into the overall conformational picture for the PIII and PIV compounds: namely, these phosphines have non-eclipsed gauche- and trans-forms with propeller arrangement of the pyridyl radicals about the P = Y bond (Y = lone pair, O, S, Se).

Vereshchagina, Yana A.; Chachkov, Denis V.; Alimova, Alsu Z.; Malysheva, Svetlana F.; Gusarova, Nina K.; Ishmaeva, Eleonora A.; Trofimov, Boris A.

2014-11-01

36

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

PubMed

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

Liu, Yong-Biao

2012-06-01

37

Acute phosphine poisoning? A case report and review.  

PubMed

A case compatible with an acute phosphine poisoning after inhalation is presented. The observation was notably characterized by necrosis of the nasal mucosa, the delayed onset of a pulmonary edema and myocardial injury with multisystemic involvement. A review of literature, not very prolific in this field, is included in the discussion. PMID:1329417

Schoonbroodt, D; Guffens, P; Jousten, P; Ingels, J; Grodos, J

1992-01-01

38

Formation of Phenylene Oligomers Using Platinum-Phosphine Complexes  

E-print Network

Formation of Phenylene Oligomers Using Platinum-Phosphine Complexes Nira Simhai, Carl N. Iverson, New York 14627 Received February 12, 2001 The reaction of biphenylene with a series of platinum bis by a variety of metal complexes.4 In addition, such a reaction is thermodynamically favored due

Jones, William D.

39

40 CFR 180.225 - Phosphine; tolerances for residues.  

Code of Federal Regulations, 2012 CFR

...gas or phosphide compounds that produce phosphine gas. Commodity Parts per million Almond 0.1 Avocado 0.01 Banana 0.01 Barley, grain 0.1 Cabbage, Chinese, bok choy 0.01 Cabbage, Chinese, napa 0.01 Cacao...

2012-07-01

40

40 CFR 180.225 - Phosphine; tolerances for residues.  

Code of Federal Regulations, 2013 CFR

...gas or phosphide compounds that produce phosphine gas. Commodity Parts per million Almond 0.1 Avocado 0.01 Banana 0.01 Barley, grain 0.1 Cabbage, Chinese, bok choy 0.01 Cabbage, Chinese, napa 0.01 Cacao...

2013-07-01

41

40 CFR 180.225 - Phosphine; tolerances for residues.  

Code of Federal Regulations, 2011 CFR

...gas or phosphide compounds that produce phosphine gas. Commodity Parts per million Almond 0.1 Avocado 0.01 Banana 0.01 Barley, grain 0.1 Cabbage, Chinese, bok choy 0.01 Cabbage, Chinese, napa 0.01 Cacao...

2011-07-01

42

40 CFR 180.225 - Phosphine; tolerances for residues.  

...gas or phosphide compounds that produce phosphine gas. Commodity Parts per million Almond 0.1 Avocado 0.01 Banana 0.01 Barley, grain 0.1 Cabbage, Chinese, bok choy 0.01 Cabbage, Chinese, napa 0.01 Cacao...

2014-07-01

43

Will Cassini Detect Phosphine? Results from a Ray Tracing Based Radiative Transfer Model of Saturn's Atmosphere  

Microsoft Academic Search

Application of the results from laboratory measurements of the centimeter-wavelength opacity of phosphine shows that phosphine is a likely contributor to the microwave spectrum of the upper atmospheres of Saturn and Neptune (Hoffman, Steffes, and DeBoer 2001. Laboratory Measurements of the Microwave Opacity of Phosphine: Opacity Formalism and Application to the Atmospheres of the Outer Planets. Icarus 152, 172-184). The

J. P. Hoffman; P. S. Steffes

2001-01-01

44

Phosphine complexes of lone pair bearing Lewis acceptors.  

PubMed

An overview of the synthesis, structures and reaction chemistry of coordination complexes featuring an acceptor with at least one lone pair and at least one phosphine donor is presented. One or more examples of complexes have been structurally-characterized for the majority of p-block elements but few are known for most elements. The unusual condition of a p-block element centre accommodating a lone pair of electrons and offering a low energy LUMO gives the element centre the potential to behave as both a Lewis acid and a Lewis Base. The structural diversity and reactivity of the phosphine complexes highlights new directions in main group chemistry and by comparison with transition metal coordination chemistry, the featured complexes demonstrate significant configurational and stereochemical flexibility. Ligand exchange, oxidation and reduction chemistry at the lone pair bearing acceptor centre reveals unusual reactivity and an interesting class of ligands and inorganic reagents, with new possibilities for catalysis or small molecule activation. PMID:25352363

Chitnis, Saurabh S; Burford, Neil

2015-01-01

45

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

PubMed Central

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

Fan, Yi Chiao

2014-01-01

46

Bifunctional Phosphines Immobilized on Inorganic Ch. Merckle and J. Blumel*  

E-print Network

CP/MAS, and 31P suspension NMR spectroscopy. MgO and TiO2 cannot bind the phosphine strongly, so multinuclear CP/MAS and 31P suspen- sion NMR spectroscopy as analytical tools, we investi- gated whether immobilized on MgO, TiO2, Al2O3, and SiO2 surfaces. The materials were studied by 27Al MAS, 29Si CP/MAS, 31P

Bluemel, Janet

47

Retrievals of Jovian Tropospheric Phosphine from Cassini/CIRS  

NASA Technical Reports Server (NTRS)

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

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

2004-01-01

48

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

49

Phosphine analysis in post mortem specimens following ingestion of aluminium phosphide.  

PubMed

Phosphine was detected in post mortem stomach and contents, blood, and liver specimens of a man who had ingested tablets containing aluminium phosphide. The phosphine was released from the samples after acid treatment and analysed by means of a headspace gas chromatographic technique using a nitrogen phosphorus detector. PMID:6314042

Chan, L T; Crowley, R J; Delliou, D; Geyer, R

1983-01-01

50

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...

51

Catalytic Hydrogenolysis of Biphenylene with Platinum, Palladium, and Nickel Phosphine Complexes  

E-print Network

Catalytic Hydrogenolysis of Biphenylene with Platinum, Palladium, and Nickel Phosphine Complexes of biphenylene was carried out using Pt, Pd, and Ni phosphine complexes under an atmosphere of H2 between 56(R-biphenyl)H, 4, were all viable catalysts. The resting state species in each case was complex 4. At 80 °C under

Jones, William D.

52

Asymmetric Catalytic Synthesis of P-Stereogenic Phosphines via a Nucleophilic Ruthenium Phosphido Complex  

E-print Network

Asymmetric Catalytic Synthesis of P-Stereogenic Phosphines via a Nucleophilic Ruthenium Phosphido reaction. On the basis of the strong basicity and nucleophilicity of previously reported iron and ruthenium cationic phosphine complex 2-BPh4. Deprotonation of this complex with KHMDS afforded ruthenium phosphido

Toste, Dean

53

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

54

Isocyanide and Phosphine Oxide Coordination in Binuclear Chromium Pacman Complexes  

PubMed Central

The new binuclear chromium Pacman complex [Cr2(L)] of the Schiff base pyrrole macrocycle H4L has been synthesized and structurally characterized. Addition of isocyanide, C?NR (R = xylyl, tBu), or triphenylphosphine oxide donors to [Cr2(L)] gives contrasting chemistry with the formation of the new coordination compounds [Cr2(?-CNR)(L)], in which the isocyanides bridge the two Cr(II) centers, and [Cr2(OPPh3)2(L)], a Cr(II) phosphine oxide adduct with the ligands exogenous to the cleft. PMID:24489428

2013-01-01

55

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

PubMed Central

The electronic and steric effects in the stoichiometric dehydrocoupling of secondary and primary phosphine–boranes H3B·PR2H [R = 3,5-(CF3)2C6H3; p-(CF3)C6H4; p-(OMe)C6H4; adamantyl, Ad] and H3B·PCyH2 to form the metal-bound linear diboraphosphines H3B·PR2BH2·PR2H and H3B·PRHBH2·PRH2, respectively, are reported. Reaction of [Rh(L)(?6-FC6H5)][BArF4] [L = Ph2P(CH2)3PPh2, ArF = 3,5-(CF3)2C6H3] with 2 equiv of H3B·PR2H affords [Rh(L)(H)(?,?-PR2BH3)(?1-H3B·PR2H)][BArF4]. These complexes undergo dehydrocoupling to give the diboraphosphine complexes [Rh(L)(H)(?,?2-PR2·BH2PR2·BH3)][BArF4]. With electron-withdrawing groups on the phosphine–borane there is the parallel formation of the products of B–P cleavage, [Rh(L)(PR2H)2][BArF4], while with electron-donating groups no parallel product is formed. For the bulky, electron rich, H3B·P(Ad)2H no dehydrocoupling is observed, but an intermediate Rh(I) ? phosphine–borane complex is formed, [Rh(L){?2-H3B·P(Ad)2H}][BArF4], that undergoes B–P bond cleavage to give [Rh(L){?1-H3B·P(Ad)2H}{P(Ad)2H}][BArF4]. The relative rates of dehydrocoupling of H3B·PR2H (R = aryl) show that increasingly electron-withdrawing substituents result in faster dehydrocoupling, but also suffer from the formation of the parallel product resulting from P–B bond cleavage. H3B·PCyH2 undergoes a similar dehydrocoupling process, and gives a mixture of stereoisomers of the resulting metal-bound diboraphosphine that arise from activation of the prochiral P–H bonds, with one stereoisomer favored. This diastereomeric mixture may also be biased by use of a chiral phosphine ligand. The selectivity and efficiencies of resulting catalytic dehydrocoupling processes are also briefly discussed. PMID:24617924

2014-01-01

56

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

57

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

58

Investigating the Dearomative Rearrangement of Biaryl Phosphine-Ligated Pd(II) Complexes  

E-print Network

A series of monoligated L·Pd[superscript II](Ar)X complexes (L = dialkyl biaryl phosphine) have been prepared and studied in an effort to better understand an unusual dearomative rearrangement previously documented in these ...

Maimone, Thomas J.

59

Phosphine-catalyzed dearomatizing [3+2] annulations of isoquinolinium methylides with allenes.  

PubMed

A phosphine-catalyzed dearomatizing [3+2] annulation of isoquinolinium methylides with allenoates or allenones yields highly functionalized pyrroloisoquinolines with high regioselectivity and in viable yields. PMID:25434405

Jia, Zhi-Jun; Daniliuc, Constantin Gabriel; Antonchick, Andrey P; Waldmann, Herbert

2015-01-21

60

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

61

Acute phosphine poisoning following ingestion of aluminium phosphide.  

PubMed

1. Eight cases of phosphine poisoning following ingestion of aluminium phosphide tablets for suicidal attempt are described. The mean age of the patients was 23 years (range 14-25). 2. The clinical picture consisted of gastritis, altered sensorium and peripheral vascular failure in all cases, cardiac arrhythmia (3), jaundice and renal failure (1 each). Six patients died, the mean hospital stay was 19 h (range 4-72). 3. Post-mortem examination was performed in two patients, revealing pulmonary oedema, gastrointestinal mucosal congestion, petechial haemorrhages on the surface of liver and brain. Histopathological changes included pulmonary oedema, desquamation of the lining epithelium of the bronchioles; vacuolar degeneration of hepatocytes, dilatation and engorgement of hepatic central veins, sinusoids and areas showing nuclear fragmentation. 4. The clinical picture of aluminum phosphide poisoning is described and precaution in the distribution and use of this pesticide recommended. PMID:3410483

Misra, U K; Tripathi, A K; Pandey, R; Bhargwa, B

1988-07-01

62

Biosynthesis of Phosphonic and Phosphinic Acid Natural Products  

PubMed Central

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

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

2009-01-01

63

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

64

Enantioselective Cyclizations of Silyloxyenynes Catalyzed by Cationic Metal Phosphine Complexes  

PubMed Central

The discovery of complementary methods for enantioselective transition-metal-catalyzed cyclization with silyloxyenynes has been accomplished using chiral phosphine ligands. Under palladium catalysis, 1,6-silyloxyenynes bearing a terminal alkyne led to the desired 5-membered ring with high enantioselectivities (up to 91% ee). As for reactions under cationic gold catalysis, 1,6- and 1,5-silyloxyenynes bearing an internal alkyne furnished the chiral cyclopentane derivatives with excellent enantiomeric excess (up to 94% ee). Modification of the substrate by incorporating an ?,?-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

2012-01-01

65

Insights into a surprising reaction: the microwave-assisted direct esterification of phosphinic acids.  

PubMed

It is well-known that phosphinic acids do not undergo direct esterifications with alcohols under thermal conditions. However, the esterifications take place under microwave (MW) irradiation due to the beneficial effect of MW. As a comparison, maximum 12-15% conversions were observed on traditional heating. It was proved experimentally that the MW-assisted esterifications are not reversible under the conditions applied that may be the consequence of the hydrophobic medium established by the long chain alcohol/phosphinic ester. Neither the thermodynamic, nor the kinetic data obtained by high level quantum chemical calculations justify the direct esterification of phosphinic acids under thermal conditions. The thermodynamic data show that there is no driving force for the reactions under discussion. As a consequence of the relatively high values of activation enthalpy (102-161 kJ mol(-1)), these esterifications are controlled kinetically. Comparing the energetics of the esterification of phosphinic acids and the preparative results obtained under MW conditions, one can see the potential of the MW technique in the synthesis of phosphinates. During our study, a series of new cyclic phosphinates with lipophilic alkyl groups was synthesized. PMID:22293944

Keglevich, György; Kiss, Nóra Zsuzsa; Mucsi, Zoltán; Körtvélyesi, Tamás

2012-03-14

66

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

PubMed

A new europium(III) membrane luminescent sensor based on a new tridentate bis(phosphinic acid)phosphine oxide (3) system has been developed. The synthesis of this new ligand is described and its full characterization by NMR, IR and elemental analyses is provided. The luminescent complex formed between europium(III) chloride and ligand 3 was evaluated in solution, observing that its spectroscopic and chemical characteristics are excellent for measuring in polymer inclusion membranes. Included in a Nafion membrane, all the parameters (ligand and ionic additives) that can affect the sensitivity and selectivity of the sensing membrane as well as the instrumental conditions were carefully optimized. The best luminescence signal (?exc = 229.06 nm and ?em = 616.02 nm) was exhibited by the sensing film having a Nafion?:?ligand composition of 262.3?:?0.6 mg mL(-1). The membrane sensor showed a short response time (t95 = 5.0 ± 0.2 min) and an optimum working pH of 5.0 (25 mM acetate buffer solution). The membrane sensor manifested a good selectivity toward europium(III) ions with respect to other trivalent metals (iron, chromium and aluminium) and lanthanide(III) ions (lanthanum, samarium, terbium and ytterbium), although a small positive interference of terbium(III) ions was observed. It provided a linear range from 1.9 × 10(-8) to 5.0 × 10(-6) M with a very low detection limit (5.8 × 10(-9) M) and sensitivity (8.57 × 10(-7) a.u. per M). The applicability of this sensing film has been demonstrated by analyzing different kinds of spiked water samples obtaining recovery percentages of 95-97%. PMID:23967443

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

2013-10-21

67

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

E-print Network

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

Trenkle, James D. (James Douglas)

2007-01-01

68

Rh 2[( R)-(+)-MTPA] 4 as an NMR auxiliary for the enantiodifferentiation of chiral secondary and tertiary phosphine–borane complexes  

Microsoft Academic Search

The direct chiral recognition of secondary and tertiary phosphine–borane complexes is made possible by applying the dirhodium method (NMR in the presence of Rh2[(R)-(+)-MTPA]4, Rh?). Due to the acid lability of the phosphine–borane complexes, it is advisable to use deuterated benzene as solvent rather than deuterated chloroform. The decomposition of the phosphine–borane complexes and the resulting Rh?–phosphine adducts are also

Jens Mattiza; Dieter Albert; Marek Stankevi?; Kamil Dziuba; Anna Szmigielska; K. Micha? Pietrusiewicz; Helmut Duddeck

2006-01-01

69

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

PubMed

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

Yang, Yonghong; Coward, James K

2007-07-20

70

Three fatalities involving phosphine gas, produced as a result of methamphetamine manufacturing.  

PubMed

In August of 1996, Sheriff's deputies investigated the deaths of three individuals suspected to have been overcome by phosphine gas. Phosphine is an extremely toxic gas, and is generally seen in the farming industry where it is used as a grain fumigant. It can also be generated as a by-product during the manufacturing of methamphetamine. Chemicals and equipment consistent with the manufacturing of methamphetamine were noted at the location, as well as an apparent reaction mixture heated to near dryness. Dräger tubes detected an atmospheric phosphine concentration in excess of 0.3 parts per million (ppm), the Threshold Limit Value. Deputies had initially assessed the scene with no protective equipment, raising concerns about phosphine toxicity and the effects of exposure. The objectives of this paper are to describe how phosphine is formed during the manufacture of methamphetamine, to review the toxicity, health effects and symptoms of exposure, to address the safety concerns regarding potential exposure to law enforcement personnel, and to describe the protective equipment available for personnel who respond to clandestine laboratories. PMID:10408124

Willers-Russo, L J

1999-05-01

71

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 (PH 3) fumigation. In a comparative study, both treatments were found to be effective for disinfecting the stored samples. Phosphine showed no appreciable decontaminating effects on microorganisms contaminated including coliforms, while 5 kGy irradiation was sufficient to control all microorganisms related to the quality of the packed samples. Irradiation at 5 kGy caused negligible changes in physicochemical attributes of the samples, such as ginsenosides, amino acids, fatty acids, and organoleptic properties, whereas phosphine fumigation was found detrimental to sensory flavor ( P<0.01). Quality deterioration occurred in the commercially-packed samples was in the following order: the control, 10 kGy-, phosphine-, and 2.5-5 kGy-treated samples. Accordingly, irradiation at <5 kGy was found to be an effective alternative to phosphine fumigation for white ginseng.

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

2000-03-01

72

ATP-dependent ligases in trypanothione biosynthesis – kinetics of catalysis and inhibition by phosphinic acid pseudopeptides  

PubMed Central

Glutathionylspermidine is an intermediate formed in the biosynthesis of trypanothione, an essential metabolite in defence against chemical and oxidative stress in the Kinetoplastida. The kinetic mechanism for glutathionylspermidine synthetase (EC 6.3.1.8) from Crithidia fasciculata (CfGspS) obeys a rapid equilibrium random ter-ter model with kinetic constants KGSH = 609 ?m, KSpd = 157 ?m and KATP = 215 ?m. Phosphonate and phosphinate analogues of glutathionylspermidine, previously shown to be potent inhibitors of GspS from Escherichia coli, are equally potent against CfGspS. The tetrahedral phosphonate acts as a simple ground state analogue of glutathione (GSH) (Ki ? 156 ?m), whereas the phosphinate behaves as a stable mimic of the postulated unstable tetrahedral intermediate. Kinetic studies showed that the phosphinate behaves as a slow-binding bisubstrate inhibitor [competitive with respect to GSH and spermidine (Spd)] with rate constants k3 (on rate) = 6.98 × 104 m?1·s?1 and k4 (off rate) = 1.3 × 10?3 s?1, providing a dissociation constant Ki = 18.6 nm. The phosphinate analogue also inhibited recombinant trypanothione synthetase (EC 6.3.1.9) from C. fasciculata, Leishmania major, Trypanosoma cruzi and Trypanosoma brucei with Kiapp values 20–40-fold greater than that of CfGspS. This phosphinate analogue remains the most potent enzyme inhibitor identified to date, and represents a good starting point for drug discovery for trypanosomiasis and leishmaniasis. PMID:18959765

Oza, Sandra L; Chen, Shoujun; Wyllie, Susan; Coward, James K; Fairlamb, Alan H

2008-01-01

73

Occupational exposure to aluminium phosphide and phosphine gas? A suspected case report and review of the literature.  

PubMed

The manufacture and application of aluminium phosphide fumigants pose risks of inhalation exposure to phosphine gas. This article presents a case report of suspected inhalation exposure to phosphine gas in a manufacturing facility for aluminium phosphide fumigants, which was associated with acute dyspnoea, hypotension, bradycardia and other signs of intoxication. These symptoms resolved within several hours after removal from exposure. A review of the data on human exposures to phosphide fumigants identifies both pesticide applicators and individuals in the vicinity of application to be at risk of accidental exposure and injury from phosphine inhalation. More recent reports have identified risks of phosphine gas inhalation in association with the clandestine production of methamphetamine. Toxicodynamic effects of phosphine result from the inhibition of cytochrome c oxidase and subsequent generation of reactive oxygen species. There remain unanswered questions relating to the toxicokinetics of phosphine, as well as the assessment of human exposure utilizing biomarkers. As initial signs and symptoms of intoxication from phosphine gas may be nonspecific and transient, there is a need for improved recognition of the potential hazards associated with phosphide fumigants and phosphine gas. PMID:15727053

Sudakin, D L

2005-01-01

74

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. PMID:21699183

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

2011-01-01

75

Fat and oil inhibit phosphine release from aluminium phosphide--its clinical implication.  

PubMed

Poisoning by suicidal or accidental ingestion of aluminium phosphide (AlP) is a frequent medical emergency seen all over the world. AlP, a grain fumigant and rodenticide, on exposure to moisture, liberates highly toxic gas, phosphine. The rapidly inhibits mitochondrial respiration and has cytotoxic action. No specific antidote is known against it till date and prognosis depends much on dose and time lag between AlP ingestion and the stomach wash in the hospital (critical period). Physicochemical properties of AlP and nonmiscibility of fat and water promoted us to study the effect of different fats and oils as possible antidotes to inhibit phosphine liberation. In vitro experiments revealed that vegetable oils and liquid paraffin were much more effective than butter and ghee in inhibiting release of phosphine from AlP. These findings may have significant clinical implication. PMID:7814045

Goswami, M; Bindal, M; Sen, P; Gupta, S K; Avasthi, R; Ram, B K

1994-09-01

76

Phosphine adsorption and the production of phosphide phases on Cu(0 0 1)  

NASA Astrophysics Data System (ADS)

The adsorption and thermal decomposition of PH 3 on a Cu(0 0 1) surface has been investigated by means of high-resolution helium atom scattering, Auger electron spectroscopy and temperature programmed desorption. Phosphine adsorption at Tx<160 K produces a molecular overlayer structure with short-range order. Annealing of the low-temperature structure results in decomposition of the adsorbed PH 3, and desorption of hydrogen between Tx=250 K and Tx=320 K. Molecular phosphine was not seen to desorb. Phosphine deposition at room temperature or above produces well-ordered copper-phosphorus phases exhibiting either c(6×8) or c(6×6) diffraction patterns, depending upon the deposition conditions. Auger electron spectra indicate that these ordered phases contain approximately 1/3 ML or more of phosphorus. Possible atomic models for the overlayer structures are discussed.

Goncharova, L. V.; Clowes, S. K.; Fogg, R. R.; Ermakov, A. V.; Hinch, B. J.

2002-09-01

77

Adducts of Rh2[MTPA]4 with some phosphine chalcogenides: nature of binding and ligand exchange.  

PubMed

Adducts of four phosphine chalcogenides with the chiral dirhodium complex ([Rh-Rh]) were investigated by variable-temperature 1H and 31P NMR spectroscopy in order to compare their properties as axial ligands. Whereas the selenide (1) and the sulfide (2) are strong ligands with electrostatic attraction and, in addition, a significant orbital (HOMO-LUMO) interaction, the phosphine oxide compounds (P=O) bind primarily via electrostatic attraction and are relatively weak donors. Moreover, the overall bond strength in these adducts depends on steric congestion around the P=O group. PMID:15181630

Gáti, Tamás; Simon, András; Tóth, Gábor; Magiera, Damian; Moeller, Stefan; Duddeck, Helmut

2004-07-01

78

Design, Synthesis, and Metal Binding of Novel Pseudo-Oligopeptides Containing Two Phosphinic Acid Groups  

E-print Network

Design, Synthesis, and Metal Binding of Novel Pseudo- Oligopeptides Containing Two Phosphinic Acid and Molecular Biophysics, Washington University School of Medicine, 660 S. Euclid Avenue, St. Louis, MO 63110 2 Department of Chemistry, Washington University School of Medicine, 660 S. Euclid Avenue, St. Louis, MO 63110

Marshall, Garland R.

79

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

E-print Network

.5747 Garching, Germany 29Si CP MAS NMR shows that a transition-metalcomplex with two bifunctional phosphine or an addition reaction to surface siloxane groups takes place.'3 This can be seen in the 29Si CP MAS NMR-state NMR study Klaus D. Behringer and Janet Blumel" Anorganisch-chemisches Institut der TU Miinchen, 8

Bluemel, Janet

80

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

PubMed

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

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

2015-01-21

81

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

PubMed Central

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

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

2014-01-01

82

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

PubMed

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

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

2014-01-01

83

Probing site cooperativity of frustrated phosphine/borane Lewis pairs by a polymerization study.  

PubMed

The first highly active phosphine (P)/borane (B) Lewis pair polymerization is promoted unexpectedly by P-B adducts. The P and B site cooperativity is essential for achieving effective polymerization, as shown by this study examining the reactivity of a library of P/B Lewis pairs toward polymerization of a renewable acrylic monomer. PMID:24417317

Xu, Tieqi; Chen, Eugene Y-X

2014-02-01

84

Development of Ruthenium Catalysts for the Enantioselective Synthesis of P-Stereogenic Phosphines via Nucleophilic  

E-print Network

Development of Ruthenium Catalysts for the Enantioselective Synthesis of P-Stereogenic Phosphines the development of ruthenium(II) catalysts for the enantioselective alkylation of chiral racemic secondary asymmetric environment around the ruthenium center. The (R)-MeO- BiPHEP/dmpe (dmpe ) 1,2-bis

Toste, Dean

85

A Nanoscale Model Catalyst Preparation: Solution Deposition of Phosphine-Stabilized Gold Clusters onto a  

E-print Network

A Nanoscale Model Catalyst Preparation: Solution Deposition of Phosphine-Stabilized Gold Clusters-oxide support model catalyst systems. A solution deposition method was devised. Six-atom gold clusters, in the form of [Au6(PPh3)6][BF4]2 (Au6L6), were deposited onto a TiO2(110) single crystal after an acetone

Goodman, Wayne

86

Temporary Protection of H-Phosphinic Acids as a Synthetic Strategy  

PubMed Central

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

Coudray, Laëtitia

2013-01-01

87

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

ERIC Educational Resources Information Center

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

Montgomery, Craig D.

2013-01-01

88

Preparation of Cadmium Selenide-Polyolefin Composites from Functional Phosphine Oxides and Ruthenium-Based  

E-print Network

Preparation of Cadmium Selenide-Polyolefin Composites from Functional Phosphine OxidesVersity of Massachusetts, Amherst, Massachusetts 01003 Received November 21, 2001 Abstract: Cadmium selenide nanoparticles by employing more easily handled cadmium sources, such as CdO. Both methods give well-defined nanoparticles

89

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

90

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

91

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

92

High temperature partition functions and thermodynamic data for ammonia and phosphine  

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

93

Total Synthesis of (±)-Hirsutine: Application of Phosphine-Catalyzed Imine–Allene [4 + 2] Annulation  

PubMed Central

The total synthesis of the indole alkaloid hirsutine has been achieved, with a key step being the application of our phosphine-catalyzed [4 + 2] annulation of an imine with ethyl ?-methylallenoate. From commercially available indole-2-carboxaldehyde, the target was synthesized in 14 steps and 6.7% overall yield. PMID:22920858

Villa, Reymundo A.; Xu, Qihai; Kwon, Ohyun

2012-01-01

94

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

95

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

E-print Network

, has been developed. It yields the well-defined H2O2 adducts as key intermediates, which have been fully characterized and methods for their controlled and efficient decomposition are described. For adsorbed phosphine oxides, the changes of the 31P...

Hilliard, Casie Renee

2013-12-09

96

Phosphine-catalyzed reductions of alkyl silyl peroxides by titanium hydride reducing agents: development of the method and mechanistic investigations.  

PubMed

A method that allows for the reduction of protected hydroperoxides by employing catalytic amounts of phosphine is presented. The combination of a titanium(IV) alkoxide and a siloxane allowed for the chemoselective reduction of phosphine oxides in the presence of alkyl silyl peroxides. Subsequent reduction of the peroxide moiety by phosphine provided the corresponding silylated alcohols in useful yields. Mechanistic experiments, including crossover experiments, support a mechanism in which the peroxide group was reduced and the silyl group was transferred in a concerted step. Labeling studies with (17)O-labeled peroxides demonstrate that the oxygen atom adjacent to the silicon atom is removed from the silyl peroxide. PMID:20604518

Harris, Jason R; Haynes, M Taylor; Thomas, Andrew M; Woerpel, K A

2010-08-01

97

Chemoselective synthesis of trifluoromethylated ?-butenolide derivatives via phosphine-promoted tandem reaction of allylic carbonates and trifluoromethyl ketones.  

PubMed

A novel chemoselective phosphine-mediated tandem reaction between nonsubstituted MBH carbonates and aryl trifluoromethyl ketones is described. The product selectivity of the reaction is easily tunable by changing the ratios of the two reactants, and mono- or bicyclic bistrifluoromethylated vinyl ?-butenolide products can be prepared with good chemoselectivity in modest-to-good yields and diastereoselectivities. The formation of the bicyclic ?-butenolide structures via a one-pot four-step sequence under phosphine catalysis is unprecedented. PMID:25296160

Xiao, Hua; Duan, Hong-yu; Ye, Jun; Yao, Ri-sheng; Ma, Juan; Yuan, Zhe-zhe; Zhao, Gang

2014-10-17

98

Preparation of phosphinated polymer-incarcerated palladium and its application to C-N and C-C bond-forming reactions.  

PubMed

Phosphinated polymer-incarcerated (PI) Pd catalysts were prepared by immobilization of palladium with phosphinated polymers by using the PI method. The phosphinated PI Pd catalysts showed good catalytic activity without externally added phosphine ligands in the amination of aryl halides for C-N bond-forming reactions, as well as in Suzuki-Miyaura and Sonogashira coupling. No leaching of palladium from the immobilized Pd was observed by fluorescence X-ray analysis. Furthermore, it was found that immobilization of Pd by the PI process facilitated the suppression of poisoning of the metal by amines. These effects can be ascribed to stabilization of the catalyst by both the phosphine moieties and the benzene rings in the swollen polymer support. The phosphinated PI Pd catalysts could also be recovered by simple filtration and reused several times without leaching of palladium in both the amination and Suzuki-Miyaura coupling reactions. PMID:17591724

Nishio, Ryo; Sugiura, Masaharu; Kobayashi, Shu

2007-08-01

99

Acute phosphine poisoning aboard a grain freighter. Epidemiologic, clinical, and pathological findings.  

PubMed

Two children and 29 of 31 crew members aboard a grain freighter became acutely ill after inhaling the toxic fumigant phosphine; one child died. Predominant symptoms were headache, fatigue, nausea, vomiting, cough, and shortness of breath. Abnormal physical findings included jaundice, paresthesias, ataxia, intention tremor, and diplopia. Focal myocardial infiltration with necrosis, pulmonary edema, and widespread small-vessel injury were found at postmortem examination of the dead child. The surviving child showed ECG and echocardiographic evidence of myocardial injury and transient elevation of the MB fraction of serum creatinine phosphokinase. Illness was significantly associated with living or working amidships or on the forward deck areas of the vessel. Phosphine gas was found to have escaped from the holds through a cable housing located near the midships ventilation intake and around hatch covers on the forward deck. The outbreak illustrates the hazards associated with shipboard fumigation. PMID:7382074

Wilson, R; Lovejoy, F H; Jaeger, R J; Landrigan, P L

1980-07-11

100

Selective electroless metal deposition using microcontact printing of phosphine-phosphonic acid inks.  

PubMed

We report a low-cost approach to selectively deposit films of nickel and copper on glass substrates. Our approach uses microcontact printing of organic inks containing phosphonic acid groups to bind the ink to a glass substrate and phosphine groups to bind a colloidal catalyst that initiates electroless metallization. We demonstrate this procedure by fabricating patterned nickel and copper films with areas as large as 15 cm2 and minimum feature sizes of approximately 2 microm. We present studies on the use of two ink types, an oligomer and a bifunctional molecule, and demonstrate that pattern quality and adhesion of the metallized films depends on the molecular weight of the ink and the ratio of phosphine and phosphonic acid groups. PMID:15986706

Carmichael, Tricia Breen; Vella, Sarah J; Afzali, Ali

2004-06-22

101

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

2013-07-10

102

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

NASA Technical Reports Server (NTRS)

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.

1980-01-01

103

Enantioselective Morita-Baylis-Hillman reaction promoted by L-threonine-derived phosphine-thiourea catalysts.  

PubMed

A series of bifunctional phosphine-thiourea organic catalysts based on natural amino acid scaffolds were designed and prepared. L-threonine-derived bifunctional phosphine catalysts were found to be very efficient in promoting asymmetric Morita-Baylis-Hillman (MBH) reaction of acrylates with aromatic aldehydes, affording the desired MBH adducts with up to 90% ee. To gain mechanistic insights into the reaction, the effects of adding various additives on the MBH reaction were investigated. We propose that the hydrogen bonding interactions between the thiourea moiety of the catalyst and the enolate intermediate are crucial for the stereochemical outcome of the reaction. The method described in this report may provide a practical solution to the enantioselective MBH reaction of simple acrylates. PMID:21858321

Han, Xiaoyu; Wang, Youqing; Zhong, Fangrui; Lu, Yixin

2011-10-01

104

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

NASA Technical Reports Server (NTRS)

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

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

1987-01-01

105

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

PubMed Central

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

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

2014-01-01

106

A gas chromatographic analysis of phosphine in biological material in a case of suicide.  

PubMed

In a suicide committed using aluminium phosphide (AlP) the liberated toxic phosphine gas was detected in post-mortem specimens using a headspace gas chromatographic procedure with a nitrogen-phosphorous detector (HS-GC/NPD). At autopsy a direct sampling into airtight headspace vials for a later analysis is recommended. AlP has to be considered a potent pesticide and its use and availability should be restricted as much as possible. PMID:18294792

Musshoff, F; Preuss, J; Lignitz, E; Madea, B

2008-05-20

107

Tertiary phosphine complexes of nickel(II) thiocyanate: an evaluation of the photostabilisation of polystyrene  

Microsoft Academic Search

Polystyrene films have been prepared incorporating zinc stearate and nickel(II) thiocyanate complexes of methyldiphenyl- and alkenyldiphenyl-phosphines (alkenyl=vinyl, allyl, but-3-enyl, pent-4-enyl). Investigation of the thermal and fluorescence properties of the nickel complexes indicates high thermal stability and minimal photochemical activity. Polymer films containing the zinc and nickel complexes were photodegraded under artificial conditions and referenced to a similarly exposed nickel-free standard.

M Edge; P Faulds; D. G Kelly; A McMahon; G. C Ranger; D Turner

2001-01-01

108

EXTRACTION OF GOLD fill) FROM HYDROCHLORIC ACID SOLUTIONS BY TRI-ISOBUTYL PHOSPHINE SULFIDE IN TOLUENE  

Microsoft Academic Search

The extractant th-isobutyl phosphine sulfide (TIBPS ), Cyanex 471, in toluene has been investigated for the extraction of Au (III) from aqueous HCI solutions. Analysis of the equilibrium data shows that the extraction proceeds via a solvating type mechanism by the formation of the species AuCI3.FI and AuCl3.2R, for which formation constants are log 677 ?= 34.84 and log ?=

V. Salvadó; M. Hidalgo; A. Masana; M. Mufioz; M. Valiente; M. Muhammed

1990-01-01

109

Fire retardant systems in poly(methyl methacrylate): Interactions between metal oxide nanoparticles and phosphinates  

Microsoft Academic Search

In the course of our investigations on halogen-free fire-retardant solutions for PMMA, the influence of oxide nanoparticles (TiO2, Al2O3) on the thermal stability and fire behaviour of PMMA blended with phosphinate additives (Exolit OP930 and OP1311) has been studied by thermogravimetric analysis and cone calorimetry. For each mixture, the residues obtained after combustion were examined and characterized by SEM, X-ray

A. Laachachi; M. Cochez; E. Leroy; M. Ferriol; J. M. Lopez-Cuesta

2007-01-01

110

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

111

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

NASA Astrophysics Data System (ADS)

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

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

2007-09-01

112

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

113

Low temperature phosphine fumigation for postharvest control of western flower thrips (Thysanoptera: Thripidae) on lettuce, broccoli, asparagus, and strawberry.  

PubMed

U.S. exported lettuce, broccoli, asparagus, and strawberries often harbor western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), a quarantined pest in Taiwan, and therefore require quarantine treatment. Fumigation with diluted pure phosphine at a low temperature of 2 degrees C was studied to control western flower thrips and to determine effects on the quality of the treated products. Total thrips control was achieved in > or = 18-h fumigation treatments with > or = 250 ppm phosphine. One day fumigation treatment with 1,000 ppm phosphine was tested on lettuce and broccoli. One-day fumigation treatments with 500 ppm and 1,000 ppm phosphine were tested on asparagus and strawberry. Visual quality of lettuce, broccoli, and asparagus was evaluated after 2-wk posttreatment storage. Strawberry quality was evaluated immediately after fumigation and after 1-wk posttreatment storage. For all the products, there were no significant differences between the treatments and the controls in postharvest quality, and there were no injuries caused by the fumigation treatments. Therefore, phosphine fumigation at low temperature was promising for postharvest control of western flower thrips on lettuce, broccoli, asparagus, and strawberry. PMID:19133457

Liu, Yong-Biao

2008-12-01

114

Synthesis and characterization of phosphine adducts of thorium borohydride, Crystal structures of Th(BH4)4(PEt3)2 and Th(BH4)4(Me2PCH2CH2PMe2)2  

E-print Network

Synthesis and characterization of phosphine adducts of thorium borohydride, Th(BH4)4 Crystal: Thorium Phosphine Trialkylphosphine Borohydride Tetrahydroborate Crystal structures a b s t r a c NMR spectroscopy. The results show that thorium complexes of unidentate phosphines can be made

Girolami, Gregory S.

115

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

PubMed

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

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

2015-02-27

116

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

117

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

118

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

119

Efficient synthesis of sulfonic, phosphoric, and phosphinic esters employing alkylating polymer-bound reagents.  

PubMed

The efficient esterification of various sulfonic acids and sulfonates using polymer-bound triazenes based on the triazene T2 linker is described. Esterification of enantiopure alpha-substituted sodium sulfonates was performed in the presence of an alkylating resin without racemization. Racemization is a serious drawback in the esterification route via sulfonyl chlorides because of intermediate sulfene formation. To demonstrate the versatility of this protocol, phosphoric and phosphinic acids have been converted into the corresponding esters as well. All products were obtained in good yield and excellent purities without any further purification steps. PMID:12625703

Vignola, Nicola; Dahmen, Stefan; Enders, Dieter; Bräse, Stefan

2003-01-01

120

Processing and characterization of monodisperse phosphine-free CdSe colloidal quantum dots  

NASA Astrophysics Data System (ADS)

In this research, mono-dispersed quantum dots of CdSe were produced using a phosphine-free approach to synthesis of colloidal quantum dots. Selenium precursor was selected as the main precursor. It was found that the initial concentration ratio of monomers critically controlled the size distribution of the nanoparticles through its influence on the growth kinetics of these particles. The best result was obtained using an initial Se/Cd ratio of 5 where CdSe quantum dots of a uniform size were synthesized. This was manifested in the absorption spectra of these particles by occurrence of sharp peaks at a wavelength of about 615 nm.

Maghsoudi, Hadi; Mahboub, Melika; Asgari, Sirous

2014-08-01

121

Synthesis, characterisation and reactions of phosphine-substituted alkynylboronates and alkynyltrifluoroborate salts.  

PubMed

The synthesis and structural characterisation of phosphine-substituted alkynylboronates is reported. A P(III)-centred alkynylboronate (2) was prepared that showed little evidence for the conjugation of the P-lone pair to the boron via the alkyne ?-system, as judged by X-ray crystallography studies of 2 and a related P(V) compound, 3. In addition, corresponding alkynyltrifluoroborate salts were prepared that showed improved stability by comparison to their boronic ester counterparts. These salts undergo Pd-catalysed cross-coupling reactions with aryl halides. PMID:25529019

Vivat, Jérôme F; Bachollet, Sylvestre P J T; Adams, Harry; Harrity, Joseph P A

2014-01-01

122

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

123

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

124

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

NASA Astrophysics Data System (ADS)

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

Gürtekin Seden, Merve; Ba?türk, Emre; Inan, Tülay Y.; Kayaman Apohan, Nilhan; Güngör, Atilla

2014-12-01

125

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

PubMed Central

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

Kele?, Tu?ba; Serinda?, Osman

2014-01-01

126

Interplay of structural and electronic stabilizing factors in neutral and cationic phosphine protected Au13 clusters  

NASA Astrophysics Data System (ADS)

Stable ligand protected sub-nanometer metal clusters exist as different structural isomers which mainly differ by the geometry of the metal core. The structural and electronic properties of the bare and phosphine protected gold, Au13, clusters were theoretically investigated in order to elucidating the relation between different metal core geometries, electronic structures and the stability of the complex. For neutral and low (3+) charged bare clusters, bilayers and flake geometries are computed to be more stable than the icosahedral geometry while for the cation 5+ the most stable metal core exhibits a regular icosahedral geometry. Flake geometries are composed of edge-fused gold tetrahedron motifs and triangular rings. The binding with phosphine induces their stabilization with respect to the bilayer and icosahedral structures. Unexpectedly, the stabilization of the ligated flake geometry with respect to the compact icosahedral-based core increases with the positive overall charge of the complex, being maximum for the highly charged species [Au13 (PH3)10]5+. The origin of the stability is explained in connection with electronic structure and the charge transfer induced by the ligand shell. The distribution of the spin density of the neutral Au13(PH3)12 with a flat cage metal core is characterized.

Fresch, B.; Hanozin, E.; Dufour, F.; Remacle, F.

2012-12-01

127

Inhibition of egg development by phosphine in the cosmopolitan pest of stored products Liposcelis bostrychophila (Psocoptera: Liposcelididae).  

PubMed

Phosphine-induced delay in development of eggs was investigated as a mechanism of resistance to this fumigant in Liposcelis bostrychophila Badonnel. One-day-old eggs of a susceptible and a strongly resistant strain of L bostrychophila were exposed to a range of phosphine concentrations for 6days at 30 (+/- 1) degrees C and 70 (+/- 2)% RH. Delay in mean hatching period occurred in both susceptible and resistant eggs, although it was more pronounced in the latter. A maximum delay of 2.65 days was recorded for eggs of the susceptible strain at 0.01 mg litre(-1) (the highest concentration at which eggs survived) and 13.39 days for the resistant strain at 1 mg litre(-1) (the highest concentration tested). Delay in egg development time was positively correlated with increasing phosphine concentration. Our results reveal that the most successful strategy to control resistant L bostrychophila is to apply relatively low concentrations of phosphine for extended exposure times (eg 0.05 mg litre(-1) for 16 days) that allow all eggs to hatch to the much less tolerant nymph stage. PMID:14620044

Nayak, Manoj K; Collins, Patrick J; Pavic, Hervoika; Kopittke, Rosemary A

2003-11-01

128

Enantioselective Direct Mannich Reactions of Cyclic ?-Ketoesters Catalyzed by Chiral Phosphine via a Novel Dual-Reagent Catalysis.  

PubMed

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

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

2015-02-01

129

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

PubMed

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

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

2012-06-14

130

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. PMID:22363681

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

2012-01-01

131

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

SciTech Connect

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

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

2013-03-07

132

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

133

On the catalytic hydrodefluorination of fluoroaromatics using nickel complexes: the true role of the phosphine.  

PubMed

Homogeneous catalytic hydrodefluorination (HDF) of fluoroaromatics under thermal conditions was achieved using nickel(0) compounds of the type [(dippe)Ni(?(2)-C6F6-nHn)] where n = 0-2, as the catalytic precursors. These complexes were prepared in situ by reacting the compound [(dippe)Ni(?-H)]2 with the respective fluoroaromatic substrate. HDF seems to occur homogeneously, as tested by mercury drop experiments, producing the hydrodefluorinated products. However, despite previous findings by other groups, we found that these HDF reactions were actually the result of direct reaction of the alkylphosphine with the fluoroaromatic substrate. This metal- and silane-free system is the first reported example of a phosphine being able to hydrodefluorinate on its own. PMID:24432839

Arévalo, Alma; Tlahuext-Aca, Adrian; Flores-Alamo, Marcos; García, Juventino J

2014-03-26

134

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

NASA Technical Reports Server (NTRS)

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

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

1986-01-01

135

Carbonylation of iodobenzene catalyzed by water-souble palladium–phosphine complexes in ionic liquid  

Microsoft Academic Search

The carbonylation of iodobenzene catalyzed by water-soluble palladium–TPPTS complex (TPPTS: trisodium salt of tri(m-sulphonylphenyl)phosphine) has been investigated in ionic liquid 1-n-butyl-3-methylimidazolium p-toluenesulfonate ([bmim][p-CH3C6H4SO3]) in the presence of alcohol. The ionic liquid [bmim][p-CH3C6H4SO3] used as the reaction media brings some definitive advantages over the halogen-containing analogue [bmim]BF4, [bmim]PF6 and conventional organic solvents. The combination of palladium–TPPTS complex and [bmim][p-CH3C6H4SO3] exhibits excellent

Qi Lin; Chaofen Yang; Weidong Jiang; Hua Chen; Xianjun Li

2007-01-01

136

Reactivity of rhenium(V) oxo Schiff base complexes with phosphine ligands: rearrangement and reduction reactions.  

PubMed

The symmetric rhenium(V) oxo Schiff base complexes trans-[ReO(OH2)(acac2en)]Cl and trans-[ReOCl(acac2pn)], where acac2en and acac2pn are the tetradentate Schiff base ligands N,N'-ethylenebis(acetylacetone) diimine and N,N'-propylenebis(acetylacetone) diimine, respectively, were reacted with monodentate phosphine ligands to yield one of two unique cationic phosphine complexes depending on the ligand backbone length (en vs pn) and the identity of the phosphine ligand. Reduction of the Re(V) oxo core to Re(III) resulted on reaction of trans-[ReO(OH2)(acac2en)]Cl with triphenylphosphine or diethylphenylphosphine to yield a single reduced, disubstituted product of the general type trans-[Re(III)(PR3)2(acac2en)]+. Rather unexpectedly, a similar reaction with the stronger reducing agent triethylphosphine yielded the intramolecularly rearranged, asymmetric cis-[Re(V)O(PEt3)(acac2en)]+ complex. Reactions of trans-[Re(V)O(acac2pn)Cl] with the same phosphine ligands yielded only the rearranged asymmetric cis-[Re(V)O(PR3)(acac2pn)]+ complexes in quantitative yield. The compounds were characterized using standard spectroscopic methods, elemental analyses, cyclic voltammetry, and single-crystal X-ray diffraction. The crystallographic data for the structures reported are as follows: trans-[Re(III)(PPh3)2(acac2en)]PF6 (H48C48N2O2P2Re.PF6), 1, triclinic (P), a = 18.8261(12) A, b = 16.2517(10) A, c = 15.4556(10) A, alpha = 95.522(1) degrees , beta = 97.130(1) degrees , gamma = 91.350(1) degrees , V = 4667.4(5) A(3), Z = 4; trans-[Re(III)(PEt2Ph)2(acac2en)]PF6 (H48C32N2O2P2Re.PF6), 2, orthorhombic (Pccn), a = 10.4753(6) A, b =18.4315(10) A, c = 18.9245(11) A, V = 3653.9(4) A3, Z = 4; cis-[Re(V)O(PEt3)(acac2en)]PF6 (H33C18N2O3PRe.1.25PF6, 3, monoclinic (C2/c), a = 39.8194(15) A, b = 13.6187(5) A, c = 20.1777(8) A, beta = 107.7730(10) degrees , V = 10419.9(7) A3, Z = 16; cis-[Re(V)O(PPh3)(acac2pn)]PF6 (H35C31N2O3PRe.PF6), 4, triclinic (P), a = 10.3094(10) A, b =12.1196(12) A, c = 14.8146(15) A, alpha = 105.939(2) degrees , beta = 105.383(2) degrees , gamma = 93.525(2) degrees , V = 1698.0(3) A3, Z = 2; cis-[Re(V)O(PEt2Ph)(acac2pn)]PF6 (H35C23N2O3PRe.PF6), 5, monoclinic (P2(1)/n), a = 18.1183(18) A, b = 11.580(1) A, c = 28.519(3) A, beta = 101.861(2) degrees , V = 5855.9(10) A(3), Z = 4. PMID:15792474

Benny, Paul D; Green, Jenny L; Engelbrecht, Hendrik P; Barnes, Charles L; Jurisson, Silvia S

2005-04-01

137

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

138

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

PubMed

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

Notni, Johannes; Šime?ek, Jakub; Wester, Hans-Jürgen

2014-06-01

139

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

PubMed Central

A convenient route for the synthesis of Fmoc-protected phosphinic dipeptide building blocks is described. The protected amino acid isosteres benzyloxycarbonyl aminomethyl phosphinic acid (glycine surrogate), benzyl ?-isopropyl acrylate (valine surrogate), and benzyl ?-isobutyl acrylate (leucine surrogate) were synthesized starting from commercially available materials. Reaction of either the valine or leucine surrogate with bis(trimethylsilyl) phosphonite generated the pseudodipeptide bond. The synthesis concluded with an efficient one-pot three-step procedure involving a bis-deprotection of the N- and C-termini under catalytic hydrogenation conditions followed by selective capping of the N-terminus with an Fmoc group to yield either Fmoc-NHCH2PO(OAd)CH2CH(Pri)CO2H or Fmoc-NHCH2PO(OAd)CH2CH(Bui)CO2H. PMID:20225219

Bhowmick, Manishabrata; Sappidi, Ravinder R.; Fields, Gregg B.; Lepore, Salvatore D.

2012-01-01

140

35 Cl, 79 Br, and 127 I NQR spectra and crystallographic parameters of some halomethylated phosphine oxides  

Microsoft Academic Search

1.The35Cl,79Br, and127I NQR spectra and the crystallographic parameters of a number of halomethylated phosphine oxides were measured.2.A structural nonequivalence of the bromine atoms was detected in (CH2Br)3PO.3.Phase transitions, with a change in the multipleticity of the NQR spectra, were recorded in (CH2Cl)3PO and (CH2I)3PO in the range 77–296°K.

V. V. Saatsazov; T. L. Khotsyanova; S. I. Kuznetsov

1975-01-01

141

Biphasic telomerization of 1,3-butadiene with HNEt 2 catalyzed by palladium\\/sulphonated–phosphine complexes  

Microsoft Academic Search

The catalytic telomerization of 1,3-butadiene with diethylamine has been performed using palladium\\/sulfonated–phosphine complexes immobilized in 1-n-butyl-3-methylimidazolium tetrafluoroborate [BMI][BF4] ionic liquid. This process affords selectively 1-octadienyl amines with high E\\/Z ratios. The rate of product formation as well as the regioselectivity of the reaction was found to depend largely on the ligand and catalyst concentrations. Selectivities of up to 99% in

Gledison Santos Fonseca; Roberto Fernando de Souza; Jairton Dupont

2002-01-01

142

Phosphine resistance in the cigarette beetle Lasioderma serricorne (Coleoptera: Anobiidae) and overcoming control failures during fumigation of stored tobacco  

Microsoft Academic Search

Survivalship of the life stages of the cigarette beetle, Lasioderma serricorne F. (Coleoptera: Anobiidae), was recorded in tobacco bales that were fumigated under a gas?proof cover with phosphine at the rate of 1–1.25 g\\/m for 7 or 8 days with the terminal concentration at > 0.1 g\\/m in warehouses at Ongole, Andhra Pradesh, India. Screening tests at the discriminating concentration

S. Rajendran; K. S. Narasimhan

1994-01-01

143

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

SciTech Connect

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

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

2008-10-03

144

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

PubMed

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

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

2015-01-01

145

Differences between amine- and phosphine-boranes: synthesis, photoelectron spectroscopy, and quantum chemical study of the cyclopropylic derivatives.  

PubMed

Borane complexes of aziridine, phosphirane, cyclopropylamine, cyclopropylphosphine, cyclopropylmethylamine, and cyclopropylmethylphosphine have been prepared by the reaction at low temperatures of a borane complex or diborane on the free phosphine or amine. The products characterized by NMR spectroscopy and mass spectrometry have then been investigated by photoelectron spectroscopy and B3LYP/aug-cc-pVTZ quantum chemical study. The complexation led to rotamers with structures similar to the ones of the corresponding free systems. The main geometry change with the complexation is the P-C bond elongation and the N-C bond shortening, which can be rationalized by the charge transfer attached to the electron donation. The calculated relative stability order of the conformers changes with the complexation only in the case of cyclopropylamine. The calculated complexation energies are higher for the amines, in accord with the differences observed in the flash vacuum thermolysis of methylamine-, methylphosphine-, and aziridine-borane. The photoelectron spectra indicate essential differences between the amines and phosphines toward borane complexation. The dative bond is more stable in the studied amine-boranes than in phosphine-boranes, while the sigma(B-H) orbitals are more stable in the latter compounds. The enthalpy of the hydrogen release reaction of aziridine-borane is almost thermoneutral, indicating the potential of this complex as recyclable hydrogen storage material. PMID:20433190

Németh, Balázs; Khater, Brahim; Guillemin, Jean-Claude; Veszprémi, Tamás

2010-06-01

146

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

NASA Astrophysics Data System (ADS)

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

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

2015-01-01

147

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. PMID:22461899

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

2012-01-01

148

Palladium-Catalyzed Suzuki-Miyaura Cross-coupling Reactions Employing Dialkylbiaryl Phosphine Ligands  

PubMed Central

Conspectus The cores of many types of polymers, ligands, natural products, and pharmaceuticals contain biaryl or substituted aromatic structures, and efficient methods of synthesizing these structures are crucial to the work of a broad spectrum of organic chemists. Recently, Pd-catalyzed carbon-carbon bond-forming processes, particularly the Suzuki–Miyaura cross-coupling reaction (SMC), have risen in popularity for this purpose. The SMC has many advantages over other methods for constructing these moieties, including mild conditions, high tolerance toward functional groups, the commercial availability and stability of its reagents, and the ease of handling and separating byproducts from its reaction mixtures. Until 1998, most catalysts for the SMC employed triarylphosphine ligands. More recently, new bulky and electron-rich phosphine ligands, which can dramatically improve the efficiency and selectivity of such cross-coupling reactions, have been introduced. In the course of our studies on carbon-nitrogen bond-forming reactions, we found that the use of electron-rich and bulky phosphines enhanced the rate of both the oxidative addition and reductive elimination processes; this was the beginning of our development of a new family of ligands, the dialkylbiarylphosphines L1–L12. These ligands can be used for a wide variety of palladium-catalyzed carbon–carbon, carbon–nitrogen, and carbon–oxygen bond-forming processes as well as serving as supporting ligands for a number of other reactions. The enhanced reactivity of these catalysts has expanded the scope of cross-coupling partners that can be employed in the SMC. Using such dialkylbiarylphosphine ligands, the coupling of unactivated aryl chlorides, aryl tosylates, heteroaryl systems, and very hindered substrate combinations have become routine. The utility of these ligands has been successfully demonstrated in a wide number of synthetic applications, including industrially relevant processes. In this account, we provide an overview of the use and impact of dialkylbiarylphosphine ligands in the SMC. We discuss our studies on the mechanistic framework of the reaction, which have allowed us to rationally modify the ligand structures in order to tune their properties. We also describe selected applications in the synthesis of natural products and new materials to illustrate the utility of these dialkylbiarylphosphine ligands in various “real-world” synthetic applications. PMID:18620434

Martin, Ruben; Buchwald, Stephen L.

2008-01-01

149

Phosphine oxide adducts of tin(IV) chloride: Experimental NMR and DFT computational study  

NASA Astrophysics Data System (ADS)

The stereochemistry of four octahedral complexes SnCl 4·2(O)PCl(NR 2) 2 (R = Me ( 1); R = Et ( 2)) and SnCl 4·2(O)PCl 2NR 2 (R = Me ( 3); R = Et ( 4)) was studied by both multinuclear ( 1H, 31P and 119Sn) NMR spectroscopy in solution and density functional theory (DFT) calculation. The NMR data suggest the presence in dichloromethane solutions of a mixture of cis and trans isomers for 1 and 2, whereas only the cis isomer is observed for 3 and 4. Moreover, the latter complexes showed partial ligand dissociation in solution. The assignment of the cis and trans isomers was based on the NMR chemical shifts and particularly on the magnitude of the 2J( 31P- 119Sn) coupling constant obtained in both solution NMR and DFT studies. In addition, the stereochemistry observed was shown to be highly dependent on the steric hinderance and/or the Lewis basicity of the phosphine oxide ligand. DFT/B3LYP calculations which compared favourably with the experimental data provided further insight into the coordination at the tin atom. The results obtained for both complexes are compared with those of the hexamethylphosphoramide complex.

Ben Dhia, M. T.; Sanhoury, M. A. M. K.; Owono Owono, L. C.; Khaddar, M. R.

2008-12-01

150

Bacterial carbon-phosphorus lyase: products, rates, and regulation of phosphonic and phosphinic acid metabolism.  

PubMed Central

Carbon-phosphorus bond cleavage activity, found in bacteria that utilize alkyl- and phenylphosphonic acids, has not yet been obtained in a cell-free system. Given this constraint, a systematic examination of in vivo C-P lyase activity has been conducted to develop insight into the C-P cleavage reaction. Six bacterial strains were obtained by enrichment culture, identified, and characterized with respect to their phosphonic acid substrate specificity. One isolate, Agrobacterium radiobacter, was shown to cleave the carbon-phosphorus bond of a wide range of substrates, including fosfomycin, glyphosate, and dialkyl phosphinic acids. Furthermore, this organism processed vinyl-, propenyl-, and propynylphosphonic acids, a previously uninvestigated group, to ethylene, propene, and propyne, respectively. A determination of product stoichiometries revealed that both C-P bonds of dimethylphosphinic acid are cleaved quantitatively to methane and, furthermore, that the extent of C-P bond cleavage correlated linearly with the specific growth rate for a range of substrates. The broad substrate specificity of Agrobacterium C-P lyase and the comprehensive characterization of the in vivo activity make this an attractive system for further biochemical and mechanistic experiments. In addition, the failure to observe the activity in a group of gram-positive bacteria holds open the possibility that a periplasmic component may be required for in vivo expression of C-P lyase activity. PMID:3804975

Wackett, L P; Shames, S L; Venditti, C P; Walsh, C T

1987-01-01

151

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

PubMed

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±42 ng m(-2) h(-1), with a mean flux of 14.4±22.5 ng m(-2) h(-1). The fluxes were both negative and positive during the diurnal period, indicating that the lake can act as a sink and a source of PH3. In addition, the PH3 fluxes were positively correlated with water temperature, total soluble phosphorus and soluble reactive phosphorus, while they were negatively correlated with water redox potential. A similar diurnal variation curve of atmospheric PH3 concentrations was observed during all four seasons, with the maximum level occurring in early morning and the minimum appearing around midday. These findings suggest that light plays an important role in the elimination of atmospheric PH3. A significant positive correlation was also found between air temperature and atmospheric PH3 concentration. The mean flux of PH3 in Lake Taihu was higher than in other reported wetlands, with an estimated annual emission of PH3 to the atmosphere of 2.94×10(5) g y(-1). PMID:21094975

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

2011-02-01

152

Photopolymerization of aromatic acrylate containing phosphine oxide backbone and its application to holographic recording  

NASA Astrophysics Data System (ADS)

Photopolymer compositions for holographic recording were prepared from aromatic diacrylate having phosphine oxide backbone, a hybrid sol-gel, and photoinitiator. The physical and holographic properties of photopolymer were controlled by the ratio of precursor triethoxysilylpropyl polyethyleneglycol carbamate (TSPEG) in a hybrid sol-gel binder and the content of monomer. The photopolymerization rate and conversion of monomer were monitored by photo-differential scanning calorimetry (photo-DSC). Holographic recording was attempted by photopolymerization of the monomers in the photopolymer film using a 532 nm laser. Holographic gratings were written into the photopolymer samples by interfering two collimated plane wave beams. The temporal growth of the diffracted power was monitored in real-time at 785 nm laser. Contents of monomer and TESPEG were changed in the range of 0-60 wt% and the composition were optimized in terms of diffraction efficiency. Photopolymer film exhibited very high diffraction efficiency of 93.5% and low shrinkage (<0.5%) after the contents of monomer, binder, and TSPEG were optimized.

Chang, Yu Mi; Yoon, Sung Cheol; Han, Mijeong

2007-12-01

153

Matrix-bound phosphine, phosphorus fractions and phosphatase activity through sediment profiles in Lake Chaohu, China.  

PubMed

The distribution patterns of matrix-bound phosphine (MBP), phosphorus (P) fractions and neutral phosphatase activity (NPA) were investigated through five sediment profiles in Lake Chaohu, China. MBP was discovered in all sediment profiles within the concentration range of 1.58-50.34 ng kg(-1). These concentrations exhibited a consistent vertical distribution pattern in all profiles, and higher concentrations generally occurred in surface sediments. MBP concentrations showed a significant positive correlation with P fractions, total nitrogen (TN), Cu and Zn under lower levels of inorganic phosphorus (<0.6 g kg(-1)), organic phosphorus (<0.2 g kg(-1)), TN (<0.13%), Cu (<25 mg kg(-1)) and Zn (<150 mg kg(-1)), but no statistically significant correlations were obtained under higher levels. A multiple stepwise regression model ([MBP]=1.36[NPA]-6.21[pH]-0.06[Zn]+0.75[Cu]+49.86) was obtained between MBP concentrations and environmental variables, and MBP concentrations showed a strong positive correlation with NPA (P<0.0001). This indicates that the production of sediment MBP was controlled by microbially mediated processes in Lake Chaohu. This model could be used to predict MBP levels in the sediments. Our results indicate that MBP levels could not be used as indicators for the degree of lake eutrophication. The study of sediment MBP, P factions and NPA will improve our understanding of P cycling and their environmental significance in the eutrophic Lake Chaohu. PMID:24706054

Ding, Wei; Zhu, Renbin; Hou, Lijun; Wang, Qing

2014-05-01

154

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

155

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

PubMed

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

Morales-Bayuelo, Alejandro; Caballero, Julio

2015-03-01

156

Phosphine-containing HYNIC derivatives as potential bifunctional chelators for (99m)Tc-labeling of small biomolecules.  

PubMed

Two prototype phosphine-containing HYNIC chelators, HYNIC-Kp-DPPB and HYNIC-Ko-DPPB (HYNIC = 6-hydrazinonicotinamide; K = lysine; and DPPB = diphenylphosphine-benzoic acid), have been synthesized and characterized by NMR ((1)H, (13)C, and (31)P) and LC-MS. Macrocyclic (99m)Tc complexes, [(99m)Tc(HYNIC-Ko-TPPB)(tricine)] and [(99m)Tc(HYNIC-Kp-DPPB)(tricine)], were prepared by reacting the phosphine-containing HYNIC chelator with (99m)TcO(4)(-) in the presence of excess tricine and stannous chloride. Results from this study clearly demonstrated that both HYNIC-Kp-DPPB and HYNIC-Ko-DPPB are able to form highly stable macrocyclic (99m)Tc complexes, [(99m)Tc(HYNIC-Ko-TPPB)(tricine)] and [(99m)Tc(HYNIC-Kp-DPPB)(tricine)], when tricine is used as the coligand. Radio-HPLC data suggest that the complex [(99m)Tc(HYNIC-Kp-DPPB)(tricine)] exists as only one detectable isomer in solution while the complex [(99m)Tc(HYNIC-Ko-DPPB)(tricine)] has three isomers. It was also found that three isomers of [(99m)Tc(HYNIC-Ko-DPPB)(tricine)] interconvert at elevated temperatures, suggesting that the presence of these isomers might be due conformational changes in the macrocyclic Tc chelate. The LC-MS data for both macrocyclic (99m)Tc complexes are completely consistent with the proposed composition. The phosphine-containing HYNIC chelators described in this study may have the potential as bifunctional chelators for (99m)Tc labeling of small biomolecules. PMID:12862424

Purohit, Ajay; Liu, Shuang; Casebier, Dave; Edwards, D Scott

2003-01-01

157

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

PubMed

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

Magnusson, R; Rittfeldt, L; Åstot, C

2015-01-01

158

Insights into Functional-Group-Tolerant Polymerization Catalysis with Phosphine-Sulfonamide Palladium(II) Complexes.  

PubMed

Two series of cationic palladium(II) methyl complexes {[(2-MeOC6 H4 )2 PC6 H4 SO2 NHC6 H3 (2,6-R(1) ,R(2) )]PdMe}2 [A]2 ((X) 1(+) -A: R(1) =R(2) =H: (H) 1(+) -A; R(1) =R(2) =CH(CH3 )2 : (DIPP) 1(+) -A; R(1) =H, R(2) =CF3 : (CF3) 1(+) -A; A=BF4 or SbF6 ) and neutral palladium(II) methyl complexes {[(2-MeOC6 H4 )2 PC6 H4 SO2 NC6 H3 (2,6-R(1) ,R(2) )]PdMe(L)} ((X) 1-acetone: L=acetone; (X) 1-dmso: L=dimethyl sulfoxide; (X) 1-pyr: L=pyridine) chelated by a phosphine-sulfonamide were synthesized and fully characterized. Stoichiometric insertion of methyl acrylate (MA) into all complexes revealed that a 2,1 regiochemistry dominates in the first insertion of MA. Subsequently, for the cationic complexes (X) 1(+) -A, ?-H elimination from the 2,1-insertion product (X) 2(+) -AMA-2,1 is overwhelmingly favored over a second MA insertion to yield two major products (X) 4(+) -AMA-1,2 and (X) 5(+) -AMA . By contrast, for the weakly coordinated neutral complexes (X) 1-acetone and (X) 1-dmso, a second MA insertion of the 2,1-insertion product (X) 2MA-2,1 is faster than ?-H elimination and gives (X) 3MA as major products. For the strongly coordinated neutral complexes (X) 1-pyr, no second MA insertion and no ?-H elimination (except for (DIPP) 2-pyrMA-2,1 ) were observed for the 2,1-insertion product (X) 2-pyrMA-2,1 . The cationic complexes (X) 1(+) -A exhibited high catalytic activities for ethylene dimerization, affording butenes (C4 ) with a high selectivity of up to 97.7?% (1-butene: 99.3?%). Differences in activities and selectivities suggest that the phosphine-sulfonamide ligands remain coordinated to the metal center in a bidentate fashion in the catalytically active species. By comparison, the neutral complexes (X) 1-acetone, (X) 1-dmso, and (X) 1-pyr showed very low activity towards ethylene to give traces of oligomers. DFT analyses taking into account the two possible coordination modes (O or N) of the sulfonamide ligand for the cationic system (CF3) 1(+) suggested that the experimentally observed high activity in ethylene dimerization is the result of a facile first ethylene insertion into the O-coordinated PdMe isomer and a subsequent favored ?-H elimination from the N-coordinated isomer formed by isomerization of the insertion product. Steric hindrance by the N-aryl substituent in the neutral systems (CF3) 1 and (H) 1 appears to contribute significantly to a higher barrier of insertion, which accounts for the experimentally observed low activity towards ethylene oligomerization. PMID:25487160

Jian, Zhongbao; Falivene, Laura; Wucher, Philipp; Roesle, Philipp; Caporaso, Lucia; Cavallo, Luigi; Göttker-Schnetmann, Inigo; Mecking, Stefan

2015-01-26

159

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

160

Anaerobic utilization of phosphite/phosphine as a sole source of phosphorus - Implication to growth in the Jovian environment  

NASA Technical Reports Server (NTRS)

The ability of anaerobic soil isolate microorganisms to metabolize hypophosphite as the sole phosphorus source was studied. Isolates were inoculated into defined medium; growth was determined by turbidity readings, and concentrations of P-32-hypophosphite and its metabolites were determined. Evidence for growth was obtained. Experiments will be performed to see if anaerobes can use phosphine as a sole phosphorous source; the ability of earth organisms to utilize reduced forms of phosphorus would suggest that contaminating organisms from earth would not be eliminated by the absence of phosphate in the Jovian atmosphere.

Foster, T. L.; Winans, L., Jr.

1977-01-01

161

Synthesis of Carbocyclic Hydantocidins via Regioselective and Diastereoselective Phosphine-Catalyzed [3 + 2]-Cycloadditions to 5-Methylenehydantoins  

SciTech Connect

The phosphine-catalyzed [3 + 2]-cycloaddition of 5-methylenehydantoins 4 with the ylides 5, derived from addition of tributylphosphine to the 2-butynoic acid derivatives, 6a-d, gives spiro-heterocyclic products. The camphor sultam derivative 6b gives optically active products. Noteable was that the ylides derived from ethyl 2-butynoate and the 3-(2-butynoyl)-1,3-oxazolidin-2-one derivatives 6c and 6d gave spiro-heterocyclic products with reverse regioselectivities. The N,N-dibenzylprotected cycloadduct has been converted to carbocyclic hydantocidin and 6,7-diepi-carbocyclic hydantocidin.

Pham, Tien Q.; Pyne, Stephen G.; Skelton, Brian W.; White, Allan H. (UWA); (Wollongong)

2010-07-20

162

Secondary phosphine oxides: tautomerism and chiral recognition monitored by multinuclear NMR spectroscopy of their Rh2[(R)-MTPA]4 adducts.  

PubMed

Six secondary phosphine oxides and their tautomeric equilibria as free ligands and in the presence of an equimolar amount of the chiral dirhodium complex Rh* are described and discussed. Discrimination of enantiomers is easily possible by inspecting the (31)P NMR resonances; some (1)H and (13)C NMR resonances are useful as well. H/D exchange of the acidic protons in the phosphine oxides takes place with acetone-d(6), the solvent additive, after some hours but does not obscure the chiral recognition experiment. (103)Rh,(31)P coupling constants are discussed briefly. Decomposition of ligand molecules in 1:1-Rh*-adducts occurs slowly but completely. PMID:14628300

Magiera, Damian; Szmigielska, Anna; Pietrusiewicz, K Michal; Duddeck, Helmut

2004-01-01

163

Phosphine-catalyzed enantioselective ?-addition of 3-substituted oxindoles to 2,3-butadienoates and 2-butynoates: use of prochiral nucleophiles.  

PubMed

The first phosphine-catalyzed enantioselective ?-addition with prochiral nucleophiles and 2,3-butadienoates as the reaction partners has been developed. Both 3-alkyl- and 3-aryl-substituted oxindoles could be employed in this process, which is catalyzed by a chiral phosphine that is derived from an amino acid, thus affording oxindoles that bear an all-carbon quaternary center at the 3-position in high yields and excellent enantioselectivity. The synthetic value of these ?-addition products was demonstrated by the formal total synthesis of two natural products and by the preparation of biologically relevant molecules and structural scaffolds. PMID:24520067

Wang, Tianli; Yao, Weijun; Zhong, Fangrui; Pang, Guo Hao; Lu, Yixin

2014-03-10

164

Vertical Profiles of Phosphine and Ammonia on Saturn Derived from the First Cassini RSS Occultation Observation Using Forward Modeling  

NASA Astrophysics Data System (ADS)

The results from the first Cassini Radio Science Subsystem(RSS) occultation, which occurred at the Rev 7 periapse, are being used to derive profiles of the atmospheric constituents encountered by the three frequency (S-, X-, and Ka-band) radio link. A computer model has been developed to simulate ray paths and the ray path parameters in the atmosphere of Saturn encountered during occultation (see Mohammed and Steffes, Bull. Amer. Astron. Soc., 36, no. 4, 1107, 2004). This forward model, which can be used on any oblate planet, will be used to determine the refractive defocusing and derive the profiles of phosphine and ammonia using data observed at Ka-band (32 GHz or 9.3 mm), X-band (8.4 GHz or 3.6 cm) and S-band (2.3 GHz or 13 cm). The results of laboratory measurements of the 9 mm opacity of phosphine and ammonia (Mohammed and Steffes, ICARUS 166, 425-435, 2003) and the centimeter wavelength opacity of these constituents measured under simulated conditions for Saturn (see, e.g., Hoffman et. al. ICARUS 152, 172-184, 2001) were incorporated into the forward radio occultation model used in these derivations.

Mohammed, P. N.; Steffes, P. G.; Kliore, A. J.; Anabtawi, A.; Asmar, S. W.; Barbinis, E.; Goltz, G.; Johnston, D.; Marouf, E. A.

2005-08-01

165

Synthesis of novel and diverse naphtho[1,2-b]furans by phosphine-catalyzed [3+2] annulation of activated 1,4-naphthoquinones and acetylenecarboxylates.  

PubMed

A new phosphine-catalyzed [3+2] annulation reaction between activated 1,4-naphthoquinones and acetylenecarboxylates is described. This reaction provides a facile and efficient route to a variety of biologically promising and novel naphtho[1,2-[Formula: see text

Xia, Likai; Somai Magar, Krishna Bahadur; Lee, Yong Rok

2015-02-01

166

Intramolecular C?H/O?H Bond Cleavage with Water and Alcohol Using a Phosphine-Free Ruthenium Carbene NCN Pincer Complex.  

PubMed

Transition metal complexes that exhibit metal-ligand cooperative reactivity could be suitable candidates for applications in water splitting. Ideally, the ligands around the metal should not contain oxidizable donor atoms, such as phosphines. With this goal in mind, we report new phosphine-free ruthenium NCN pincer complexes with a central N-heterocyclic carbene donor and methylpyridyl N-donors. Reaction with base generates a neutral, dearomatized alkoxo-amido complex, which has been structurally and spectroscopically characterized. The tert-butoxide ligand facilitates regioselective, intramolecular proton transfer through a C?H/O?H bond cleavage process occurring at room temperature. Kinetic and thermodynamic data have been obtained by VT NMR experiments; DFT calculations support the observed behavior. Isolation and structural characterization of a doubly dearomatized phosphine complex also strongly supports our mechanistic proposal. The alkoxo-amido complex reacts with water to form a dearomatized ruthenium hydroxide complex, a first step towards phosphine-free metal-ligand cooperative water splitting. PMID:25266279

Prokopchuk, Demyan E; Tsui, Brian T H; Lough, Alan J; Morris, Robert H

2014-12-15

167

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. PMID:22363668

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

2012-01-01

168

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

169

Transition metal-catalyzed dissociation of phosphine-gallane adducts: isolation of mechanistic model complexes and heterogeneous catalyst poisoning studies.  

PubMed

Attempts to induce the catalytic dehydrocoupling of the phosphine-gallane adduct Cy2PH.GaH3 (Cy=cyclohexyl) (1) by treatment with ca. 5 mol% of either the Rh(I) complex [{Rh(mu-Cl)(1,5-cod)}2] (cod=cyclooctadiene) or the Rh(0) species Rh/Al2O3 and [Oct4N]Cl-stabilized colloidal Rh led to catalytic P-Ga bond cleavage to generate the phosphine, H2, and Ga metal. Interestingly, subsequent treatment of the reaction mixtures with Me2NH.BH3 failed to lead to the formation of [Me2N-BH2]2 via Rh-catalyzed dehydrocoupling, which suggested that catalyst deactivation was taking place. Poisoning studies involving the treatment of the active Rh(0) catalyst with Cy2PH, PMe3, or GaH3.OEt2 showed that deactivation indeed occurred as the dehydrocoupling of Me2NH.BH3 either dramatically decreased in rate or did not take place at all. The X-ray photoelectron spectroscopy analysis of colloidal Rh(0) that had been treated with Cy2PH and PMe3 confirmed the presence of phosphorus on the catalyst surface in each case, consistent with catalyst poisoning via phosphine ligation. A mechanism for the Rh-catalyzed P-Ga bond cleavage reaction of 1 and Me3P.GaH3 (2) is proposed and involves the initial reaction of Ga-H bonds with the Rh colloid surface, which weakens and ultimately breaks the P-Ga bond. The reasonable nature of this mechanism is supported by a model reaction between the zerovalent group 9 complex Co2(CO)8 and 2 which afforded Me3P.Ga[Co(CO)4]3 (3). Consistent with the elongated and thus weakened P-Ga bond in 3, solutions of this species in Et2O subsequently form the known complex [(Me3P)Co(CO)3]2 (4) and Ga metal after 4 h at 25 degrees C. PMID:17663543

Clark, Timothy J; Jaska, Cory A; Turak, Ayse; Lough, Alan J; Lu, Zheng-Hong; Manners, Ian

2007-09-01

170

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

PubMed Central

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

2008-01-01

171

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

NASA Astrophysics Data System (ADS)

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

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

2008-06-01

172

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

PubMed

Esophageal cancer is one of the least studied cancers and is found to be prominent in black South African males. It is mainly diagnosed in the late stages, and patients tend to have a low 5-year survival rate of only 10 %. Silver is generally used as an antimicrobial agent, with limited reports on anticancer studies. In this study, dimeric silver(I) thiocyanate complexes were used containing a variation of 4-substitued triphenylphosphines, including [AgSCN(PPh3)2]2 (1), [AgSCN{P(4-MeC6H4)3}2]2 (2), [AgSCN{P(4-FC6H4)3}2]2 (3) and [AgSCN{P(4-ClC6H4)3}2]2 (4). All four complexes, with their respective phosphine ligands, PPh3 (L1), P(4-MeC6H4)3 (L2), P(4-FC6H4)3 (L3) and P(4-ClC6H4)3 (L4), were subjected to in vitro toxicity studies in SNO-esophageal cancer cells, using an alamarBlue(®) assay. Morphological changes, including blebbing and apoptotic body formation, were observed. Phosphatidylserine externalization, a marker of apoptosis, was quantified by flow cytometry. The phosphine ligands L1-L4, on their own, had minimal effect on the malignant while complexes 1-4 resulted in significant cell death. A 10× decreased concentration of these complexes had similar effects than cisplatin, used as the positive control. These complexes show promise as anticancer agents. PMID:25547071

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

2015-02-01

173

Molybdenum Complexes Supported by Mixed NHC/Phosphine Ligands: Activation of N2 and Reaction With P(OMe)3 to the First Meta-Phosphite Complex.  

PubMed

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

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

2014-11-20

174

ULTRAVIOLET SPECTROPHOTOMETRIC DETERMINATION OF URANIUM. Separation of Uranium from Bismuth Using Tris(2-ethylhexyl)phosphine Oxide. Work completed, May 1958  

Microsoft Academic Search

An ultraviolet spectrophotometric method for the determination of ; uranium was developed which is based on the ultraviolet absorption of the complex ; of uranium(VI) with tris-(2-ethylhexyl)phosphine oxide (TEHPO). The complex is ; formed by extracting unanium(VI) from an aqueous 6M sodium nitrate solution in ; the pH range 2.5to 3.0 into 0.1M solution of TEHPO in an inert diluent,

A. H. A. Heyn; G. Banerjee

1959-01-01

175

Far-infrared spectroscopy of the giant planets: measurements of ammonia and phosphine at Jupiter and Saturn and the continuum of Neptune  

Microsoft Academic Search

We detected rotational transition features of ammonia and phosphine in the far-infrared spectra of Jupiter and Saturn and measured the far-infrared continuum of Neptune with high photometric accuracy. These observations were made with the long-wavelength spectrometer (LWS) aboard the infrared space observatory (ISO). The LWS covered the wavelength region between 43 and 197 mum (51-233 cm-1) with both medium and

M. J. Burgdorf; G. S. Orton; T. Encrenaz; G. R. Davis; E. Lellouch; S. D. Sidher; B. M. Swinyard

2004-01-01

176

Far-infrared spectroscopy of the giant planets: measurements of ammonia and phosphine at Jupiter and Saturn and the continuum of Neptune  

Microsoft Academic Search

We detected rotational transition features of ammonia and phosphine in the far-infrared spectra of Jupiter and Saturn and measured the far-infrared continuum of Neptune with high photometric accuracy. These observations were made with the long-wavelength spectrometer (LWS) aboard the infrared space observatory (ISO). The LWS covered the wavelength region between 43 and 197 ?m (51–233 cm?1) with both medium and

M. J. Burgdorf; G. S. Orton; T. Encrenaz; G. R. Davis; E. Lellouch; S. D. Sidher; B. M. Swinyard

2004-01-01

177

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

178

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

PubMed

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

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

2014-05-21

179

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

PubMed Central

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

Corfield, Peter W. R.

2014-01-01

180

Heterogeneous or homogeneous catalysis? Mechanistic studies of the rhodium-catalyzed dehydrocoupling of amine-borane and phosphine-borane adducts.  

PubMed

In depth, comparative studies on the catalytic dehydrocoupling of the amine-borane adduct Me(2)NH.BH(3) (to form [Me(2)N-BH(2)](2)) and the phosphine-borane adduct Ph(2)PH.BH(3) (to form Ph(2)PH-BH(2)-PPh(2)-BH(3)) with a variety of Rh (pre)catalysts such as [[Rh(1,5-cod)(micro-Cl)](2)], Rh/Al(2)O(3), Rh(colloid)/[Oct(4)N]Cl, and [Rh(1,5-cod)(2)]OTf have been performed in order to determine whether the dehydrocoupling proceeds by a homogeneous or heterogeneous mechanism. The results obtained suggest that the catalytic dehydrocoupling of Me(2)NH.BH(3) is heterogeneous in nature involving Rh(0) colloids, while that of Ph(2)PH.BH(3) proceeds by a homogeneous mechanism even when starting with Rh(0) precursors such as Rh/Al(2)O(3). The catalytic dehydrocoupling reactions are thought to proceed by different mechanisms due to a combination of factors such as (i) the greater reducing strength of amine-borane adducts, (ii) the increased ease of dissociation of phosphine-borane adducts, and (iii) phosphine ligation and/or poisoning of active catalytic sites on metal colloids. PMID:15291581

Jaska, Cory A; Manners, Ian

2004-08-11

181

Synthetic, structural, NMR, and computational study of a geminally bis(peri-substituted) tridentate phosphine and its chalcogenides and transition-metal complexes.  

PubMed

Coupling of two acenaphthene backbones through a phosphorus atom in a geminal fashion gives the first geminally bis(peri-substituted) tridentate phosphine 1. The rigid nature of the aromatic backbone and overall crowding of the molecule result in a rather inflexible ligand, with the three phosphorus atoms forming a relatively compact triangular cluster. Phosphine 1 displays restricted dynamics on an NMR time scale, which leads to the anisochronicity of all three phosphorus nuclei at low temperatures. Strained bis- and tris(sulfides) 2 and 3 and the bis(selenide) 4 have been isolated from the reaction of 1 with sulfur and selenium, respectively. These chalcogeno derivatives display pronounced in-plane and out-of-plane distortions of the aromatic backbones, indicating the limits of their angular distortions. In addition, we report metal complexes with tetrahedral [(1)Cu(MeCN)][BF4] (5), square planar [(1)PtCl][Cl] (6), trigonal bipyramidal [(1)FeCl2] (7), and octahedral fac-[(1)Mo(CO)3] (8) geometries. In all of these complexes the tris(phosphine) backbone is distorted, however to a significantly smaller extent than that in the mentioned chalcogenides 2-4. Complexes 5 and 8 show fluxionality in (31)P and (1)H NMR. All new compounds 1-8 were fully characterized, and their crystal structures are reported. Conclusions from dynamic NMR observations were augmented by DFT calculations. PMID:23534381

Ray, Matthew J; Randall, Rebecca A M; Arachchige, Kasun S Athukorala; Slawin, Alexandra M Z; Bühl, Michael; Lebl, Tomas; Kilian, Petr

2013-04-15

182

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

SciTech Connect

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

Ozawa, M. [4002 Narita-cho, Japan Atomic Energy Agency, O-arai-machi, Ibaraki-ken, Post No. 311-1393 (Japan); Babain, V.; Shadrin, A.; Strelkov, S.; Kiseleva, R.; Murzin, A. [2nd Murinsky Avenue, RPA V.G.Khlopin Radium Institute, 194021, Saint-Petersburg, 28 (Russian Federation)

2007-07-01

183

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

PubMed

The exact interaction between Au cores and surface ligands remains largely unknown because of the complexity of the structure and chemistry of ligand/Au-core interfaces in ligand-protected Au nanoclusters (AuNCs), which are commonly found in many organic-inorganic complexes. Here, femtosecond transient absorption measurement of the excited-state dynamics of a newly synthesized phosphine-protected cluster [Au20(PPhpy2)10Cl4]Cl2 (1) is reported. Intramolecular charge transfer (ICT) from the Au core to the peripheral ligands was identified. Furthermore, we found that solvation strongly affected ICT at ligand/Au-core interfaces while by choosing several typical alcoholic solvents with different intrinsic solvation times, we successfully observed that excited-state relaxation dynamics together with displacive excited coherent oscillation of Au20 clusters were significantly modulated through the competition between solvation and surface trapping. The results provide a fundamental understanding of the structure-property relationships of the solvation-dependent core-shell interaction of AuNCs for the potential applications in catalysis, sensing and nanoelectronics. PMID:25058805

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

2014-09-14

184

Nickel(II) complexes containing bidentate amido phosphine ligands derived from alpha-iminophosphorus ylides: synthesis and structural characterization.  

PubMed

The reactions of prop-2-ynyltriphenylphosphonium bromide with a series of primary aromatic or aliphatic amines in refluxing acetonitrile generated the corresponding 2-hydrocarbylaminoprop-1-enyltriphenylphosphonium bromide [RNHC(Me)=CHPPh(3)]+Br- (R = 2,6-C(6)H(3)iPr(2) (1a), 2,6-C(6)H(3)Me(2) (1b), Ph (1c), t-Bu (1d)) as crystalline solids. Deprotonation of 1a-d with NaH in THF at -35 degrees C afforded the alpha-iminophosphorus ylides RN=C(Me)CH=PPh(3) (2a-d) in high yield. Spectroscopic and crystallographic data of 2 suggest a strong intramolecular interaction between the imino nitrogen and the phosphorus atom. In contrast to N-arylated 2a-c, the N-tert-butyl-derived 2d is extremely moisture-sensitive. Hydrolysis of 2d led to elimination of benzene and generated concomitantly the phosphine oxide 3d that contains an ene-amine functionality. The reactions of 2a-c with Ni(COD)(2) in the presence of an excess amount of pyridine in toluene produced the divalent nickel complexes of the type [kappa(2)-RNC(Me)=CHPPh(2)]Ni(Ph)(Py) (4a-c). The solution and solid-state structures of these new compounds are presented. PMID:18081275

Lee, Pei-Ying; Liang, Lan-Chang

2008-01-21

185

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

PubMed

Tris(2-carboxyethyl)phosphine (TCEP) belongs to the trialkylphosphine class of reducing agents that are widely used in research and industry. In this paper, we discuss a sensitive high-performance liquid chromatography (HPLC) method equipped with an evaporative light scattering detector (ELSD) for the determination of TCEP in pharmaceutical samples containing therapeutic protein and stabilizing additives. TCEP was first completely oxidized with hydrogen peroxide to form TCEP oxide (TCEPO). Proteins and salts were removed from the sample by solid phase extraction. TCEPO concentrations were determined by anion exchange chromatography coupled with ELSD. Because of the 1:1 oxidation stoichiometry for the reaction, the concentration of TCEP in the sample is directly proportional to the measured concentration of TCEPO. A good linearity fit of ELSD response versus TCEPO concentration was observed over the range of 20-2000 ?M. The specificity, precision, accuracy, and robustness of the method were evaluated and suitable for the quantitation of TCEP in biological samples. Moreover, selective treatment with peroxide prior to solid-phase extraction may be used to determine the mass balance of TCEP species or track the oxidation rate in pharmaceutical samples. PMID:22019701

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

2012-02-01

186

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

E-print Network

A comprehensive hot line list is calculated for $^{31}$PH$_3$ in its ground electronic state. This line list, called SAlTY, contains almost 16.8 billion transitions between 7.5 million energy levels and it is suitable for simulating spectra up to temperatures of 1500~K. It covers wavelengths longer than 1~$\\mu$m and includes all transitions to upper states with energies below $hc \\cdot 18\\,000$~cm$^{-1}$ and rotational excitation up to $J=46$. The line list is computed by variational solution of the Schr\\"odinger equation for the rotation-vibration motion employing the nuclear-motion program TROVE. A previously reported {\\it ab initio} dipole moment surface is used as well as an updated `spectroscopic' potential energy surface (PES), obtained by refining an existing \\textit{ab initio} surface through least-squares fitting to the experimentally derived energies. Detailed comparisons with other available sources of phosphine transitions confirms SAlTY's accuracy and illustrates the incompleteness of previous ex...

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

2014-01-01

187

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

PubMed

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

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

1999-08-23

188

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

189

First direct discrimination of chiral phosphine selenide (P=Se) derivatives by multinuclear magnetic resonance spectroscopy in the presence of a chiral dirhodium complex.  

PubMed

Enantiomeric ratios of compounds with P=Se functionalities (phosphine selenides) can easily be determined by (1)H, (13)C, (31)P, and (77)Se NMR spectroscopic inspection of their diastereomeric complexes with (R)-Rh(2)(MTPA)(4) (MTPA-H identical with methoxytrifluoromethylphenylacetic acid; Mosher's acid). This is the first facile and rapid spectroscopic method for chiral recognition in this class of compounds. Whereas most complexation shifts Delta(delta) are moderate or even negligible, significant signal dispersions Delta(nu) can be observed. Some rationalization for the adduct formation mode is presented. NMR spectral characteristics of the free P=Se compounds 1-5 are described. PMID:11984756

Malik, Shahid; Duddeck, Helmut; Omelanczuk, Jan; Choudhary, Muhammad Iqbal

2002-05-15

190

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

PubMed Central

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

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

2010-01-01

191

REACTIONS OF TRANSITION METAL THIOLATO UNITS IV. FORMATION OF PHOSPHINE-CONTAINING COBALT OR NICKEL COMPLEXES WITH iso-MALEONITRILE-DITHIOLATE  

Microsoft Academic Search

The reaction of M (M=Co or Ni) with K2(i-mnt) and phosphine forms chelated ternary coordination compounds (1)-(4). The crystal structures of Ni(i-mnt)(dppmSe) (1) (in the presence of Se) and (“Bu4N”)[Co(i-mnt)2(PBu 2] (2) were determined by single-crystal X-ray diffraction analyses; (1) crystallizes in the monoclinic space group P21\\/n with a = 12.002(3), b = 19.568(11), c = 12.456(5) Å, ? =

Bei-Sheng Kang; Zhong-Ning Chen; Zhang Lin; Hua-Xin Zhang; Han-Qin Liu; Xiao-Ying Huang

1999-01-01

192

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

193

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

PubMed Central

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

2013-01-01

194

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

195

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. PMID:20502649

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

2010-01-01

196

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

PubMed

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

2012-04-27

197

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

2013-06-01

198

RXP 407, a phosphinic peptide, is a potent inhibitor of angiotensin I converting enzyme able to differentiate between its two active sites  

PubMed Central

The human somatic angiotensin converting enzyme (ACE) contains two homologous domains, each bearing a zinc-dependent active site. All of the synthetic inhibitors of this enzyme used in clinical applications interact with these two active sites to a similar extent. Recently, several lines of evidence have suggested that the N-terminal active site of ACE might be involved in specific hydrolysis of some important physiological substrates, like Acetyl-Seryl-Aspartyl-Lysyl-Proline, a negative regulator of hematopoietic stem cell differentiation and proliferation. These findings have stimulated studies aimed at identifying new ACE inhibitors able to block only one of the two active sites of this enzyme. By screening phosphinic peptide libraries, we discovered a phosphinic peptide Ac-Asp-(L)Phe?(PO2-CH2)(L)Ala-Ala-NH2, called RXP 407, which is able to differentiate the two ACE active sites, with a dissociation constant three orders of magnitude lower for the N-domain of the enzyme. The usefulness of a combinatorial chemistry approach to develop new lead structures is underscored by the unusual chemical structure of RXP 407, as compared with classical ACE inhibitors. As a highly potent and selective inhibitor of the N-terminal active site of wild ACE (Ki = 12 nM), RXP 407, which is metabolically stable in vivo, may lead to a new generation of ACE inhibitors able to block in vivo only a subset of the different functions regulated by ACE. PMID:10200262

Dive, Vincent; Cotton, Joël; Yiotakis, Athanasios; Michaud, Annie; Vassiliou, Stamatia; Jiracek, Jiri; Vazeux, Gilles; Chauvet, Marie-Thérèse; Cuniasse, Philippe; Corvol, Pierre

1999-01-01

199

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

PubMed Central

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

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

2002-01-01

200

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

2012-11-01

201

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

PubMed Central

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

2014-01-01

202

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

203

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

PubMed Central

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

2013-01-01

204

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

PubMed

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

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

2014-02-10

205

(Dithio­benzoato-?2 S,S?)[hydridotris(pyrazol-1-yl-?N 2)borato](triphenyl­phosphine-?P)ruthenium(II)  

PubMed Central

Reaction of [Ru(Tp)Cl(PPh3)2] (Tp = hydridotrispyrazolyl­borate) with ammonium dithio­benzoate in methanol leads to the formation of the title compound, [Ru(C9H10BN6)(C7H5S2)(C18H15P)]. In the crystal structure, the Ru atom is coordinated by three N atoms of the Tp ligand, one P atom of the triphenyl­phosphine ligand and the two S atoms of the dithio­benzoate ligand within a slightly distorted octa­hedron. The Ru—S bonds are slightly different [2.321?(1) and 2.396?(1)?Å] and the average N—Ru—N angle is 86.31°. PMID:21581150

Lin, Chia-Her; Liang, Yao-Ren; Tong, Hung-Chun; Lo, Yih Hsing; Kuo, Ting Shen

2008-01-01

206

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

PubMed

Highly active, air-stable and water-soluble palladium-phosphinous acid complexes have been applied to Suzuki cross-coupling reaction of heteroaryl bromides under mild conditions in water/alcoholic solvents. Suzuki cross-coupling reaction of heteroaryl bromides with phenylboronic acid occurred efficiently using palladium phosphinous acid complexes (POPd) and phase transfer catalyst (tetrabutylammonium bromide and polyethylene glycol) in water/ethanol mixture, water/propanol mixture and neat water respectively, the corresponding yields of cross-coupling heteroaryl-aryls were satisfied. The tert-butyl substituted ligand di-tert-butylphosphino in combination with POPd was found to be more active than the same family derived catalysts dipalladium complexes POPd1 and POPd2, and other two kinds of Pd-catalysts Pd(PPh3)4 and Pd2(dba)3. The mechanism of Suzuki cross-coupling reaction between heteroaryl bromides and phenylboronic acid in water was proposed with respect to the key role of phase transfer catalyst on the transmetallation step. Compared with other solid phase transfer catalysts, TBAB was tested as the ideal one. The alkalinity of base and the molar proportion between POPd and TBAB were investigated in water and alcoholic solvents. Notably, in the presence of TBAB adding alcoholic solvents into water enhanced the yields of target products. However in terms of the liquid phase transfer catalyst of PEGs, mixing water into PEGs could slightly decrease the yields with respect to the water free PEGs bulk phase, which was probably due to the homogenous liquid conditions in pure PEGs and weak interactions between PEGs and heteroaryl bromide molecules in water depending on their molecular chain lengths. PMID:24191596

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

2013-06-01

207

A Rapid Method for the Extraction and Separation of Uranium from Thorium and Other Accompanying Elements Using Octadecyl Silica Membrane Disks Modified by Tri-n-octyl Phosphine Oxide  

Microsoft Academic Search

A simple method for rapid and selective separation of uranyl ion from Th and other accompanying elements by using octadecyl silica membrane disks modified with tri-n-octyl phosphine oxide (TOPO) in the presence of 0.5 M HNO3 is presented. The influences of type and concentration of acid, nature of ligands, flow rates, and nature of stripping agents have been investigated. Maximum

MOJTABA SHAMSIPUR; YADOLLAH YAMINI; PARVIZ ASHTARI; ALI REZA KHANCHI; MOHAMMAD GHANNADI-MARAGEH

2000-01-01

208

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

SciTech Connect

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

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

1987-09-02

209

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

210

Frustrated Lewis pair modification by 1,1-carboboration: disclosure of a phosphine oxide triggered nitrogen monoxide addition to an intramolecular P/B frustrated Lewis pair.  

PubMed

The vicinal frustrated Lewis pair (FLP) mes2P-CH2CH2-B(C6F5)2 (3) reacts with phenyl(trimethylsilyl)acetylene by 1,1-carboboration to give the extended C3-bridged FLP 6 featuring a substituted vinylborane subunit. The FLP 6 actively cleaves dihydrogen. The FLP 3 also undergoes a 1,1-carboboration reaction with diphenylphosphino(trimethylsilyl)acetylene to give the P/B/P FLP 11 that features a central unsaturated four-membered heterocyclic P/B FLP and a pendant CH2CH2-Pmes2 functional group. Compound 11 reacts with nitric oxide (NO) by oxidation of the pendant Pmes2 unit to the P(O)mes2 phosphine oxide and N,N-addition of the P/B FLP unit to NO to yield the persistent P/B/PO FLPNO aminoxyl radical 14. This reaction is initiated by P(O)mes2 formation and opening of the central Ph2P···B(C6F5)2 linkage triggered by the pendant CH2CH2-P(O)mes2 group. PMID:24850528

Liedtke, René; Scheidt, Felix; Ren, Jinjun; Schirmer, Birgitta; Cardenas, Allan Jay P; Daniliuc, Constantin G; Eckert, Hellmut; Warren, Timothy H; Grimme, Stefan; Kehr, Gerald; Erker, Gerhard

2014-06-25

211

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

PubMed

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

Fu, Qiang; Yang, Limin; Wang, Qiuquan

2007-06-15

212

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

NASA Technical Reports Server (NTRS)

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

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

2006-01-01

213

Asymmetric synthesis of bis(tertiary arsines): highly stereoselective alkylations of diastereomers of a chiral phosphine-stabilized bis(arsenium triflate).  

PubMed

The addition of organolithium reagents to an equilibrating mixture of diastereomers of a phosphine-stabilized 1,2-ethanediylbis(phenylarsenium triflate) containing chiral arsenic stereocenters and an enantiomerically pure, atropisomeric tertiary phosphepine derived from lithiated (aR)-2,2'-dimethyl-1,1'-binaphthalene generates unequal mixtures of diastereomers and enantiomers of chelating 1,2-ethanediylbis(tertiary arsines), chiral at arsenic, with liberation of the (aR(P))-phosphepine. Thus, the addition of methyllithium in diethyl ether at -95 degrees C to a dichloromethane solution of the complex (R*(As),R*(As))-(+/-)/(R*(As),S*(As))-1,2-[(R(3)P)PhAsCH(2)CH(2)AsPh(PR(3))](OTf)(2), where R(3)P is (aR(P))-[2-(methoxymethyl)phenyl]phosphepine, generates (R*(As),R*(As))-(+/-)-1,2-ethanediylbis(methylphenylarsine) in 78% diastereoselectivity and 95% enantioselectivity in favor of the (R(As),R(As)) enantiomer. Under similar conditions, the addition of n-butyllithium in hexanes to a solution of the bis(phosphepine-stabilized)-diarsenium triflate at -95 degrees C gives the corresponding (R*(As),R*(As))-(+/-)-1,2-ethanediylbis[(n-butyl)phenylarsine) in 77% diastereoselectivity and 93% enantioselectivity in favor of the (R(As),R(As)) enantiomer. PMID:19555058

Weir, Michelle L; Cade, Ian A; Kilah, Nathan L; Zhou, Xiangting; Wild, S Bruce

2009-08-01

214

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

PubMed

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

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

1997-01-01

215

Computational study of the reaction of C6F6 with [IrMe(PEt3)3]: identification of a phosphine-assisted C-F activation pathway via a metallophosphorane intermediate.  

PubMed

Density functional theory calculations have been used to model the reaction of C6F6 with [IrMe(PEt3)3], which proceeds with both C-F and P-C bond activation to yield trans-[Ir(C6F5)(PEt3)2(PEt2F)], C2H4, and CH4 (Blum, O.; Frolow, F.; Milstein, D. J. Chem. Soc., Chem. Commun. 1991, 258). Using a model species, trans-[IrMe(PH3)2(PH2Et)], a low-energy mechanism involving nucleophilic attack of the electron-rich Ir metal center at C6F6 with displacement of fluoride has been identified. A novel feature of this process is the capture of fluoride by a phosphine ligand to generate a metallophosphorane intermediate [Ir(C6F5)(Me)(PH3)2(PH2EtF)]. These events occur in a single step via a 4-centered transition state, in a process that we have termed "phosphine-assisted C-F activation". Alternative mechanisms based on C-F activation via concerted oxidative addition or electron-transfer processes proved less favorable. From the metallophosphorane intermediate the formation of the final products can be accounted for by facile ethyl group transfer from phosphorus to iridium followed by beta-H elimination of ethene and reductive elimination of methane. The interpretation of phosphine-assisted C-F activation in terms of nucleophilic attack is supported by the reduced activation barriers computed with the more electron-rich model reactant trans-[IrMe(PMe3)2(PMe2Et)] and the higher barriers found with lesser fluorinated arenes. Reactivity patterns for a range of fluoroarenes indicate the dominance of the presence of ortho-F substituents in promoting phosphine-assisted C-F activation, and an analysis of the charge distribution and transition state geometries indicates that this process is controlled by the strength of the Ir-aryl bond that is being formed. PMID:18950169

Erhardt, Stefan; Macgregor, Stuart A

2008-11-19

216

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

NASA Technical Reports Server (NTRS)

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

Bosco, S. R.

1982-01-01

217

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

PubMed

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

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

2014-08-25

218

Reactions of Ph4Se4Br4 with tertiary phosphines. Structural isomerism within a series of R3PSe(Ph)Br compounds.  

PubMed

The synthesis and characterisation of Ph(4)Se(4)Br(4) (1) directly from the reaction of Ph(2)Se(2) with dibromine is reported. The solid-state structure of 1 consists of four PhSeBr units linked by weak selenium-selenium bonds [3.004(2)-3.051(2) A] into a Se(4) square, and is structurally analogous to the previously reported Ph(4)Te(4)I(4). The reactions of Ph(4)Se(4)Br(4) with a variety of tertiary phosphines have been undertaken, resulting in the formation of compounds of formula R(3)PSe(Ph)Br. X-Ray crystallographic analysis of three of the compounds reveals different structural isomers. Ph(3)PSe(Ph)Br (2) is a charge-transfer (CT) compound [Se-Br 3.0020(8) A], with an essentially linear P-Se-Br bond angle, 172.15(4) degrees and T-shaped geometry at selenium. Me(3)PSe(Ph)Br (5) also contains the selenium atom in a T-shaped geometry, consistent with a CT formulation, although the Se-Br distance of 3.327(3) A is considerably longer than observed for 2. In contrast, Cy(3)PSe(Ph)Br (6) is an ionic phosphonium salt, [Cy(3)PSePh]Br with no short Se-Br interactions. Geometry at selenium is bent, as expected for an ionic compound. These results are discussed with reference to the previously reported iodo-compounds Ph(3)PSe(Ph)I and [(Me(2)N)(3)PSe(Ph)]I. PMID:16538270

Barnes, Nicholas A; Godfrey, Stephen M; Halton, Ruth T A; Mushtaq, Imrana; Pritchard, Robin G; Sarwar, Shamsa

2006-03-28

219

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

NASA Astrophysics Data System (ADS)

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

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

2011-05-01

220

Variationally determined electronic states for the theoretical analysis of intramolecular interaction. II. Qualitative nature of the P-O bond in phosphine oxides.  

PubMed

We have developed a space-restricted wave function (SRW) method for the analysis of various types of intramolecular interactions. In this study, we demonstrate the applicability of our SRW method to the analysis of the nature of the P-O bond in phosphine oxide (R(3)PO), one of the hypervalent molecules. An interesting character of this bond has been extensively studied by focusing on the negative hyperconjugation of the O lone pair (n(O)) with the R(3)P group. We reinvestigated the nature of the bond in terms of a change in total energy to produce evidence for the validity of our method. The electronic states without the interaction involving three n(O) orbitals (R(3)P(+)-O(-)) produced by the method were used as reference states in the assessment of the effects of this n(O)-R(3)P interaction. The result confirms that this interaction plays an essential role in the nature of the bond and occurs between the n(O) orbitals and the P-R antibonding orbitals, in agreement with previous studies. A molecular orbital (MO)-pair analysis technique shows that the n(O)-R(3) P interaction is decomposed into the negative hyperconjugation and the Pauli repulsion. Considering a reference state where the P-O bond is completely broken (R(3)P(2+) · · ·O(2-)) at an interacting distance, P-O bond formation is attributed to one ? bond plus two 0.5 ? bonds. This is equivalent to three banana bonds highly polarized to the O atom. Consequently, the SRW method suggested improved explanations of the nature of the P-O bond. PMID:22987752

Yamada, Kenta; Koga, Nobuaki

2013-01-15

221

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

2013-10-01

222

The preparation of phosphine tellurides  

E-print Network

. Hofmann, J. Am. Chem. Soc. , 43, 1684 (1921); ibid, 52, 2995 (1930). 13. H. Gilman and G. E. Brown, J. Am. Chem. Soc. , 67, 824 (1945). Strong oxidants such as nitric acid (8), (12), (17), potassium chlorate (16), benzoyl peroxide (17), or peracetic... to oxidation in this manner (1). 5. C. Screttas and A. F. Isbell, J. Org. Chem. , 27, 2573 (1962). 6. R. A. Zingaro and R. E. McGlothlin, J. Chem. Eng. Data, 8, No. 2, 226 (1963). 7. N, Collie and G. A. Letts, J. Chem. Soc. 42 724 (1882); Proc. Roy. Soc...

Steeves, Brian Howard

2012-06-07

223

Chemistry of the azine phosphine ligand Z,E-PPh 2CH 2C(Bu t)=N-N=CMe(C 6H 4NO 2-4): crystal structure of [Mo(CO) 4{PPh 2CH 2C(Bu t)=N-N=CMe(C 6H 4NO 2-4)}  

Microsoft Academic Search

Condensation of Z-PPh2CH2C(But)=NNH2 with 4-nitroacetophenone gave the azine phosphine Z,E-PPh2CH2C(But)=N-N=CMe(C6H4NO2-4) (I). The corresponding phsophine oxide II was prepared by treatment of I with H2O2. The phosphine I with [Mo(CO)4(nbd)] (nbd=norbornadiene) gave [Mo(CO)4{PPh2CH2C(But)=N-N=CMe(C6H4NO2-4)}] (1a); the corresponding tungsten 1b and chromium 1c complexes were made similarly. The crystal structure of 1a was determined by X-ray diffraction and showed the presence of a

Bernard L. Shaw; Sarath D. Perera; David J. Shenton; Mark Thornton-Pett

1998-01-01

224

Organophosphorus reagents as extractants-part 3. Synergic effect of triphenyl phosphine oxide and bis(diphenyl phosphinyl) alkanes on extraction of iron(III) from thiocyanate medium with 2,4-pentdione.  

PubMed

The extraction of iron(III) from thiocyanate medium was carried out with a synergic combination of 2,4-pentdione (Hacac) and either triphenyl phosphine oxide (Ph(3) PO) or bis (diphenylphosphinyl) alkanes, Ph(2)P(O)(CH(2))(n).P(O)PH(2) [ligand abbreviation, n: dpeO(2), 2; dpbO(2), 4]. Iron(III) was quantitatively separated from its binary mixture with chromium(III), manganese(III), cobalt(II), nickel(II), zinc(II), cadmium(II), mercury(II), lead(II), magnesium(II) and from steel samples. Copper(II) and silver(I) however, interfered. The percentage extraction was 99.0%. The respective extraction constants, K(HA), K(L) or K(syn), for the extracted species, [Fe(NCS)(acac)(2)(H(2)O)] (HA Hacac), Fe(NCS)(3)L(2) [L b Ph(3)PO, dpeO(2) or dpbO(2)], or Fe(NCS)(acac)(2)L were found to be: K(HA), 1.48 x 10(3), K(L), 1.80 x 10(2) (L Ph(3)PO), 2.02 x 10(2) (L dpeO(2) or dpbO(2)) and K(syn), 1.87 x 10(6) (L Ph(3)PO), 2.56 x 10(6) [L dpeO(2) or dpbO(2)]. PMID:18965433

Lobana, T S; Bhatia, P K

1992-06-01

225

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

PubMed

The mixed-valence triiron complexes [Fe3(CO)7-x (PPh3) x (?-edt)2] (x = 0-2; edt = SCH2CH2S) and [Fe3(CO)5(?(2)-diphosphine)(?-edt)2] (diphosphine = dppv, dppe, dppb, dppn) have been prepared and structurally characterized. All adopt an anti arrangement of the dithiolate bridges, and PPh3 substitution occurs at the apical positions of the outer iron atoms, while the diphosphine complexes exist only in the dibasal form in both the solid state and solution. The carbonyl on the central iron atom is semibridging, and this leads to a rotated structure between the bridged diiron center. IR studies reveal that all complexes are inert to protonation by HBF4·Et2O, but addition of acid to the pentacarbonyl complexes results in one-electron oxidation to yield the moderately stable cations [Fe3(CO)5(PPh3)2(?-edt)2](+) and [Fe3(CO)5(?(2)-diphosphine)(?-edt)2](+), species which also result upon oxidation by [Cp2Fe][PF6]. The electrochemistry of the formally Fe(I)-Fe(II)-Fe(I) complexes has been investigated. Each undergoes a quasi-reversible oxidation, the potential of which is sensitive to phosphine substitution, generally occurring between 0.15 and 0.50 V, although [Fe3(CO)5(PPh3)2(?-edt)2] is oxidized at -0.05 V. Reduction of all complexes is irreversible and is again sensitive to phosphine substitution, varying between -1.47 V for [Fe3(CO)7(?-edt)2] and around -1.7 V for phosphine-substituted complexes. In their one-electron-reduced states, all complexes are catalysts for the reduction of protons to hydrogen, the catalytic overpotential being increased upon successive phosphine substitution. In comparison to the diiron complex [Fe2(CO)6(?-edt)], [Fe3(CO)7(?-edt)2] catalyzes proton reduction at 0.36 V less negative potentials. Electronic structure calculations have been carried out in order to fully elucidate the nature of the oxidation and reduction processes. In all complexes, the HOMO comprises an iron-iron bonding orbital localized between the two iron atoms not ligated by the semibridging carbonyl, while the LUMO is highly delocalized in nature and is antibonding between both pairs of iron atoms but also contains an antibonding dithiolate interaction. PMID:24748710

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

2014-03-24

226

Insertion, coupling and elimination processes in the reactions of the unsaturated alkyl-bridged complexes [Mo?(??-C?H?)?(?-CH?R)(?-PCy?)(CO)?] (R = H, Ph) with isocyanides and secondary phosphines.  

PubMed

The methyl-bridged complex [Mo2Cp2(?-Me)(?-PCy2)(CO)2] (Cp = ?(5)-C5H5) reacted with stoichiometric amounts of CN(t)Bu at 243 K to give the C,O:C,O-bridged acyl complex [Mo2Cp2{?-C,O:C,O-C(O)Me}(?-PCy2)(CN(t)Bu)(CO)], which at room temperature slowly rearranges into its iminoacyl-bridged isomer [Mo2Cp2(?-C,N:C,N-MeCN(t)Bu)(?-PCy2)(CO)2]. In contrast, the C:O-bridged acyl complex [Mo2Cp2{?-C:O-C(O)Me}(?-PCy2)(CN(t)Bu)(CO)] was the major product obtained when the above reaction was carried out at room temperature. Density Functional Theory (DFT) was used to find the most likely structures of all these isomers, of which the iminoacyl complex was the absolute minimum. In contrast to the above reactions, up to three molecules of the ligand added rapidly to the methyl complex when using the aryl isocyanides CNR (R = o-C6H4Me, p-C6H4OMe), triggering the coupling between the methyl ligand and one of the cyclopentadienyl groups to give the corresponding methylcyclopentadiene derivatives [Mo2Cp(?(4)-C5H5Me)(?-PCy2)(CNR)3(CO)]. Carbonylation of the latter complex (R = o-C6H4Me) induced the displacement of the ?(4)-bound ligand, but also gave small yields of the hydride derivative [Mo2Cp(?(5)-C5H4Me)(?-H)(?-PCy2){CN(o-C6H4Me)}(CO)3] (Mo-Mo = 3.2467(5) Å), the latter resulting from a C-H cleavage in the methylcyclopentadiene ligand. The reaction of the title complexes with phosphines HPR (R' = Et, Ph) gave two major products: the corresponding aldehyde complexes [Mo2Cp2(?-PCy2)(?-PR){?(2)-C(O)HR}(CO)] (Mo-Mo = 2.8288(5) Å when R = CH2Ph and R' = Et) and the dicarbonyl complexes [Mo2Cp2(?-PCy2)(?-PR)(CO)2], these following from alternative reductive elimination processes, from hydrogen and either acyl or alkyl ligands, respectively. PMID:24699932

Alvarez, M Angeles; García, M Esther; García-Vivó, Daniel; Martínez, M Eugenia; Ramos, Alberto; Ruiz, Miguel A

2014-06-01

227

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

PubMed

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

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

1996-02-28

228

Combined DFT and experimental studies of C-C and C-X elimination reactions promoted by a chelating phosphine-alkene ligand: the key role of penta-coordinate Pd(II.).  

PubMed

A combined computational and experimental study of the coordination chemistry of phosphine-alkene ligand L1 (N-diphenylphosphino-7-aza-benzobicyclo[2.2.1]hept-2-ene) with Pd(0) and Pd(II) is presented. Experimentally it is established that ligand L1 promotes direct alkyl-alkyl and indirect alkyl-halide reductive elimination from Pd(II) species, affording the palladium(0) complex [Pd(?(2)-P,C-L1)2] (2) in each case. The effectiveness of L1 in promoting these reactions is attributed to the initial formation of a penta-coordinate intermediate [PdMe(X)(?(1)-P-L1)(?(2)-P,C-L1)] (X = Me, Cl) coupled with the ease with which it transforms to 2. From computation, a lower activation barrier for C(sp(3))-C(sp(3)) coupling and subsequent elimination has been computed for a stepwise associative pathway involving the initial formation of [PdMe2(?(1)-P-L1)(?(2)-P,C-L1)], compared to that computed for direct elimination from its parent, cis-[PdMe2(?(2)-P,C-L1)]. Moreover, the C(sp(3))-C(sp(3)) coupling reaction has been found to be primarily under thermodynamic control. It has also been demonstrated computationally that the methyl group of penta-coordinate [PdCl(Me)(?(1)-P-L1)(?(2)-P,C-L1)] is susceptible to nucleophilic attack by the phosphorus lone pair of a further equivalent of ligand L1, which proceeds through an SN2-like transition state. This initiates an unusual, indirect intermolecular reductive elimination process, resulting in the formation of equimolar quantities of the methyl phosphonium chloride salt of L1 and complex 2, in agreement with experimental observations. In contrast to the C(sp(3))-C(sp(3)) coupling, computation shows that this indirect C(sp(3))-Cl reductive elimination process is essentially under kinetic control. PMID:24710270

Estévez, Laura; Tuxworth, Luke W; Sotiropoulos, Jean-Marc; Dyer, Philip W; Miqueu, Karinne

2014-08-01

229

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

E-print Network

(19%) vt g. i. . Q 401 (19hV). Lo %thaethyl?, triethyl?, tri~oyyl?, trl a4atyl?, trL eyolohesyl & tripheapl & sa4 4Legoloheaylyheagiyhosyhiaeo, eoaposa4e of tho tpye I Py R~klF't Or sly bsoo bees proper%4 hg the rssetLea of the appropriate er4aaa... tetrachloride as aa iaerb eolreat for earryiag oat tho followiag roaetioas 73. N faaaa, a. N. , ~V . ~No . ~. , lo, Xsy(XSyy) aad ~. , g? gTO(X86l). 74 ~ Lasolapoff, Q ~ Ls h aa4 goaa, Ius, , New ~a)~o ~ doha Riley P + OlR ~~~) R PQR 4 ehsrseteristis...

Screttas, Constantinos G

1961-01-01

230

Benz­yl(phen­yl)phosphinic acid  

PubMed Central

The title compound, C13H13O2P, crystallized as enanti­omerically pure crystals; for the crystal measured, the P atom has R stereochemistry. The crystal structure displays O—H?O hydrogen bonding, which links individual mol­ecules related by a 21 screw axis parallel to the crystallographic a-axis direction into continuous chains. PMID:21754372

Burrow, Robert A.; Siqueira da Silva, Rubia M.

2011-01-01

231

Meth­yl(phen­yl)phosphinic acid  

PubMed Central

The crystal structure of the title compound, C7H9O2P, displays O—H?O hydrogen bonding , which links individual mol­ecules 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.

2011-01-01

232

40 CFR 721.6020 - Phosphine, dialkylyphenyl.  

Code of Federal Regulations, 2010 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)....

2010-07-01

233

Phosphines with N-heterocyclic boranyl substituents.  

PubMed

A lithio-diazaborole reacted with diamino-chlorophosphines via metathesis to yield previously unavailable phosphinoboranes bearing amino substituents at both the phosphorus and boron atoms, and with Ph2PCl and Mes*PCl2via chloride transfer and reductive PP coupling to give a chloro-diazaborole and the corresponding diphosphine or diphosphene, respectively. Diazaboroles with phenylphosphino- and PH2-substituents were nonetheless accessible via inverse metathesis upon treatment of a bromoborane precursor with phosphides PhnPH2-nM (n = 0-2, M = Li, K). The products were characterised by spectroscopic data and in most cases by single-crystal X-ray diffraction studies which show the molecules to exhibit strongly pyramidal coordination at the phosphorus atom and long BP bonds of 1.93-1.95 Å. The insensitivity of the BP distance towards substituent effects and the tolerance of large sterically induced torsional twists along the BP bond axis suggest the presence of pure single bonds without any contribution from P?B dative ?-interactions. This view was confirmed by DFT studies which indicate further that the molecules lack a significant electrophilic character at boron but may act as potential ?-donor/?-acceptor ligands through the phosphorus atom. PMID:24142130

Kaaz, M; Bender, J; Förster, D; Frey, W; Nieger, M; Gudat, D

2014-01-14

234

Phosphine photochemistry in the atmosphere of Saturn  

NASA Technical Reports Server (NTRS)

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.; Strobell, D. F.

1984-01-01

235

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

E-print Network

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

Barder, Timothy E

2007-01-01

236

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

237

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

PubMed

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 UO(2)(2+)-Br-PADAP complex in organic phase samples, in 64% (v/v) ethanol containing buffer solution (pH 7.8) and 1,2-cyclohexylenedinitrilotetraacetic acid (CyDTA) complexing agent, has been found to be at 576 nm (molar extinction coefficient, ?: 36,750 ± 240 L mol(-1)cm(-1)). Effects of various parameters like stability of complex, ethanol volume, ore matrix, interfering ions etc. on the determination of uranium have also been evaluated. Absorbance measurements as a function of time showed that colored complex is stable up to > 24h. Presence of increased amount of ethanol in colored solution suppresses the absorption of a standard UO(2)(2+)-Br-PADAP solution. Analyses of synthetic standard as well as ore leach a solution show that for 10 determination relative standard deviation (RSD) is < 2%. The accuracy of the developed method has been checked by determining uranium using standard addition method and was found to be accurate with a 98-105% recovery rate. The developed method has been applied for the analysis of a number of uranium samples generated from uranium ore leach solutions and results were compared with standard methods like inductively coupled plasma emission spectrometry (ICPAES). The determined values of uranium concentrations by these methods are within ± 2%. This method can be used to determine 2.5-250 ?g mL(-1) uranium in ore leach solutions with high accuracy and precision. PMID:22381794

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

2012-06-01

238

Phosphine-free synthesis of high-quality reverse type-I ZnSe/CdSe core with CdS/CdxZn1 - xS/ZnS multishell nanocrystals and their application for detection of human hepatitis B surface antigen  

NASA Astrophysics Data System (ADS)

Highly photoluminescent (PL) reverse type-I ZnSe/CdSe nanocrystals (NCs) and ZnSe/CdSe/CdS/CdxZn1 - xS/ZnS core/multishell NCs were successfully synthesized by a phosphine-free method. By this low-cost, 'green' synthesis route, more than 10 g of high-quality ZnSe/CdSe/CdS/CdxZn1 - xS/ZnS NCs were synthesized in a large scale synthesis. After the overgrowth of a CdS/CdxZn1 - xS/ZnS multishell on ZnSe/CdSe cores, the PL quantum yields (QYs) increased from 28% to 75% along with the stability improvement. An amphiphilic oligomer was used as a surface coating agent to conduct a phase transfer experiment, core/multishell NCs were dissolved in water by such surface modification and the QYs were still kept above 70%. The as-prepared water dispersible ZnSe/CdSe/CdS/CdxZn1 - xS/ZnS core/multishell NCs not only have high fluorescence QYs but also are extremely stable in various physiological conditions. Furthermore, a biosensor system (lateral flow immunoassay system, LFIA) for the detection of human hepatitis B surface antigen (HBsAg) was developed by using this water-soluble core/multishell NCs as a fluorescent label and a nitrocellulose filter membrane for lateral flow. The result showed that such ZnSe/CdSe/CdS/CdxZn1 - xS/ZnS core/multishell NCs were excellent fluorescent labels to detect HBsAg. The sensitivity of HBsAg detection could reach as high as 0.05 ng ml - 1.

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

2011-09-01

239

Structural diversity for phosphine complexes of stibenium and stibinidenium cations.  

PubMed

Reactions of trimethylphosphine or diphosphines with SbCl(3) in the presence of AlCl(3) or Me(3)SiSO(3)CF(3) give ligand stabilized stibenium and stibinidenium cations. The geometry at each antimony center reveals a variety of environments for antimony that describes new bonding and highlights new directions in the chemistry of the pnictogen elements. PMID:22011846

Chitnis, Saurabh S; Peters, Brendan; Conrad, Eamonn; Burford, Neil; McDonald, Robert; Ferguson, Michael J

2011-12-01

240

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

Code of Federal Regulations, 2010 CFR

...new uses are: (i) Industrial, commercial, and consumer activities . Requirements as specified in § 721.80(s) (100,000 kilograms/year). (ii) [Reserved] (b) Specific requirements . The provisions of subpart A of...

2010-07-01

241

The Reduction of a Nitrile (CN) Group by Sodium Borohydride. The Preparation of Phosphine--Amine and Phosphine--Iimidate Complesex of Tungsten Carbonyl.  

ERIC Educational Resources Information Center

Describes an experiment for advanced-level undergraduate students for extending student experiences involving recording and interpreting infrared (IR) and nuclear magnetic resonance (NMR) spectra from reactions of organometallic compounds. Experimental procedures, analyses and structural assignments, and suggestions for extension and modification…

Faust, Kristen E.; Storhoff, Bruce N.

1989-01-01

242

cis-cis-trans-Bis(acetonitrile-?N)dichloridobis(triphenyl­phosphine-?P)ruthenium(II) acetonitrile disolvate  

PubMed Central

The title compound, [RuCl2(C2H3N)2(C18H15P)2]·2C2H3N, was obtained upon stirring an acetonitrile/ethanol solution of [RuCl2(PPh3)3]. In the crystal structure, each RuII ion is coordinated by two Cl [Ru—Cl = 2.4308?(7) and 2.4139?(7)?Å], two N [Ru—N = 2.016?(2) and 2.003?(2)?Å], and two P [Ru—P = 2.3688?(7) and 2.3887?(7)?Å] atoms in a distorted octa­hedral geometry. Packing inter­actions include typical C—H?? contacts involving phenyl groups as well as weak hydrogen bonds between CH3CN methyl H atoms and Cl or solvent CH3CN N atoms. PMID:21200532

Al-Far, Ahmad M.; Slaughter, LeGrande M.

2008-01-01

243

Catalytic effect of phosphine on the deposition of phosphosilicate glass from tetraethoxysilane  

NASA Astrophysics Data System (ADS)

The effect of phosphorous incorporation on the deposition rate of phosphosilicate glass from the reaction of PH3, O2, and tetraethoxysilane (TEOS) has been studied. The previously reported apparent catalytic effect of PH3 on the deposition rate of SiO2 has been reproduced in this study, but by utilizing a newly designed hot-walled low-pressure chemical vapor deposition (LPCVD) reactor, homo- and heterogeneous catalytic effects were separated. These results indicate that the source of the catalytic effect is purely homogeneous, possibly involving an oxidation product of PH3 reacting with TEOS. Results obtained in a cold-wall reactor suggest that PH3 and O2 serve to poison the surface decomposition reaction of TEOS to produce SiO2.

Tedder, Laura L.; Crowell, John E.; Uram, Kevin J.; Shugrue, John K.; Tribula, D.

1993-02-01

244

Phosphine/Palladium-Catalyzed Syntheses of Alkylidene Phthalans, 3-Deoxyisoochracinic Acid, Isoochracinic Acid, and Isoochracinol  

PubMed Central

In this study we used sequential-catalysis—PPh3-catalyzed nucleophilic addition followed by Pd(0)-catalyzed Heck cyclization—to construct complex functionalized alkylidene phthalans rapidly, in high yields, and with good stereoselectivities (E:Z ratios of up to 1:22). The scope of this Michael–Heck reaction includes substrates bearing various substituents around the alkylidene phthalan backbone. Applying this efficient sequential-catalysis, we accomplished concise total syntheses of 3-deoxyisoochacinic acid, isoochracinic acid, and isoochracinol. PMID:22721256

Fan, Yi Chiao; Kwon, Ohyun

2012-01-01

245

N-Benzyl-P-(2-ethyl­phen­yl)-P-phenyl­phosphinic amide  

PubMed Central

In the crystal structure of the title compound, C21H22NOP, the amine H atom is involved in N—H?O hydrogen-bonding inter­actions, resulting in chains along the c axis. The crystal lattice is consolidated by weak inter­molecular C—H?? inter­actions. PMID:22199881

Kinfe, Henok H.; Hamese, Augustine; Hughes, Tanya; Omondi, Bernard

2011-01-01

246

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

PubMed

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

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

2014-12-22

247

Privileged phosphine-based metal-organic frameworks for broad-scope asymmetric catalysis.  

PubMed

A robust and porous Zr metal-organic framework (MOF) based on a BINAP-derived dicarboxylate linker, BINAP-MOF, was synthesized and post-synthetically metalated with Ru and Rh complexes to afford highly enantioselective catalysts for important organic transformations. The Rh-functionalized MOF is not only highly enantioselective (up to >99% ee) but also 3 times as active as the homogeneous control. XAFS studies revealed that the Ru-functionalized MOF contains Ru-BINAP precatalysts with the same coordination environment as the homogeneous Ru complex. The post-synthetically metalated BINAP-MOFs provide a versatile family of single-site solid catalysts for catalyzing a broad scope of asymmetric organic transformations, including addition of aryl and alkyl groups to ?,?-unsaturated ketones and hydrogenation of substituted alkene and carbonyl compounds. PMID:24684238

Falkowski, Joseph M; Sawano, Takahiro; Zhang, Teng; Tsun, Galen; Chen, Yuan; Lockard, Jenny V; Lin, Wenbin

2014-04-01

248

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

E-print Network

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

Lee, Sarah Yunmi

2014-01-01

249

In vitro phosphinate methylation by PhpK from Kitasatospora phosalacinea.  

PubMed

Radical 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 has 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) to form 2-acetylamino-4-hydroxymethylphosphinylbutanoate (N-acetylphosphinothricin). This transformation gives rise to the only carbon-phosphorus-carbon linkage known to occur in nature. PMID:21950770

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

2011-10-25

250

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. PMID:21950770

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

2011-01-01

251

(9H-Fluoren-9-yl)(phen­yl)phosphinic acid  

PubMed Central

The crystal structure of the title compound, C19H15O2P, features pairs of mol­ecules joined by O—H?O hydrogen bonds across crystallographic inversion centers. In addition, ?–? inter­actions, with a centroid–centroid distance of 3.6273?(9)?Å between the fluorene ring systems, connect the dimers into chains along [01-1]. The three rings make dihedral angles of 1.34?(9), 1.52?(10) and 1.51?(7)° with each other. PMID:23476362

Burrow, Robert A.; Siqueira da Silva, Rubia M.

2013-01-01

252

Diamond and Related Materials 7 (1998) 16511656 Influence of phosphine on the diamond growth mechanism  

E-print Network

) faceted crystals. These observations are discussed in terms of a model of the gas phase chemistry during the growth of phosphorus and nitrogen date, only been made by Bohr et al. [11], who discovered co (E f =10.4 eV) which suggests that P incorpo- detail: this is the subject of the present work. Bohr

Bristol, University of

253

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

NASA Astrophysics Data System (ADS)

In order to improve the spectroscopic database for remote sensing of the giant planets, line positions and intensities are determined for the five bands (2?2, ?2 + ?4, 2?4, ?1 and ?3) that comprise the Pentad of PH3 between 1950 and 2450 cm-1. Knowledge of PH3 spectral line parameters in this region is important for the exploration of dynamics and chemistry on Saturn, (using existing Cassini/VIMS observations) and future near-IR data of Jupiter from Juno and ESA's Jupiter Icy Moons Explorer (JUICE). For this study, spectra of pure PH3 from two Fourier transform spectrometers were obtained: (a) five high-resolution (0.00223 cm-1), high signal-to-noise (?1800) spectra recorded at room temperature (298.2 K) with the Bruker IFS 125HR Fourier transform spectrometer (FTS) at the Pacific Northwest National Laboratory (PNNL), Richland, Washington and (b) four high-resolution (at 0.0115 cm-1 resolution), high signal-to-noise (?700) spectra recorded at room temperature in the region 1800-5200 cm-1 using the McMath-Pierce Fourier transform spectrometer located at the National Solar Observatory (NSO) on Kitt Peak. Individual line parameters above 2150 cm-1 were retrieved by simultaneous multispectrum fittings of all five Bruker spectra, while retrievals with the four Kitt Peak spectra were done in the 1938-2168 cm-1 range spectrum by spectrum and averaged. In all, positions and intensities were obtained for more than 4400 lines. These included 53 A+A- split pairs of transitions (arising due to vibration-rotation interactions (Coriolis-type interaction) between the ?3 and ?1 fundamental bands) for K? = 3, 6, and 9. Over 3400 positions and 1750 intensities of these lines were ultimately identified as relatively unblended and modeled up to J = 14 and K = 12 with rms values of 0.00133 cm-1 and 7.7%, respectively. The PH3 line parameters (observed positions and measured intensities with known quantum assignments) and Hamiltonian constants are reported. Comparisons with other recent studies are discussed.

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

2014-04-01

254

Chain-end-functionalized polyphosphazenes via a one-pot phosphine-mediated living polymerization.  

PubMed

A simple polymerization of trichlorophosphoranimine (Cl3 P = N-SiMe3 ) mediated by functionalized triphenylphosphines is presented. In situ initiator formation and the subsequent polymerization progress are investigated by (31) P NMR spectroscopy, demonstrating a living cationic polymerization mechanism. The polymer chain lengths and molecular weights of the resulting substituted poly(organo)phosphazenes are further studied by (1) H NMR spectroscopy and size exclusion chromatography. This strategy facilitates the preparation of polyphosphazenes with controlled molecular weights and specific functional groups at the ?-chain end. Such well-defined, mono-end-functionalized polymers have great potential use in bioconjugation, surface modification, and as building blocks for complex macromolecular constructs. PMID:24700544

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

2014-06-01

255

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

PubMed Central

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

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

2014-01-01

256

Conformationally constrained N-heterocyclic phosphine-diimine with dual functionality.  

PubMed

Condensation of octahydro-2,2'-bipyrimidine with P(NMe2)3 gave a 1,3,2-diazaphospholidine-4,5-diimine 4a in which the "open" (exo/exo) conformation of the diimine unit was enforced by incorporation into a tricyclic molecular backbone. The coordination behavior of this potentially ambident ligand was sampled in reactions with ([(nbd)W(CO)4] and [CpCo(CO)2]) and pnictogen halides ECl3 (E = P, As, Sb). While PCl3 reacted under ring metathesis, all other reactions gave isolable complexes of composition (4a)MLn (MLn = W(CO)5, CpCo(CO), AsCl3, SbCl3); attempted recrystallization of the As-adduct yielded a complex (4a)(AsCl3)2 which was also accessible from reaction of 4a with 2 equiv of AsCl3. Single-crystal X-ray diffraction studies revealed that the ligand in [(4a)W(CO)5] and [(4a)CpCo(CO)] binds through its phosphorus lone-pair; [(4a)SbCl3] and [(4a)(AsCl3)2] contain a T-shaped ECl3 unit which binds to the chelating diimine moiety, and associate further via chloride bridges to give centrosymmetric dimers. Reactions of 4a with excess metal substrates gave no evidence that formation of bimetallic complexes with ?-bridging 1?(2)(N,N')-2?P-coordination is feasible; the extra AsCl3 moiety in [(4a)(AsCl3)2] avoids this coordination mode by interacting with the peripheral chlorides of the central core. The observed selectivity suggests that ligand 4a specifically addresses transition metal centers with low positive charge and some back-bonding capacity through the phosphorus lone-pair, and electrophiles that behave essentially as "pure" Lewis acids through the diimine unit. This assumption was confirmed by DFT studies which disclosed further that binding of the first metal center deactivates the opposite binding site and thus strongly inhibits the formation of dinuclear complexes. PMID:23514329

Mourgas, Georgios; Nieger, Martin; Förster, Daniela; Gudat, Dietrich

2013-04-01

257

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

258

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

E-print Network

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 ...

Sinisi, Riccardo

259

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

PubMed Central

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

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

2008-01-01

260

A nickel phosphine complex as a fast and efficient hydrogen production catalyst.  

PubMed

Here we report the electrocatalytic reduction of protons to hydrogen by a novel S2P2 coordinated nickel complex, [Ni(bdt)(dppf)] (bdt = 1,2-benzenedithiolate, dppf = 1,1'-bis(diphenylphosphino)ferrocene). The catalysis is fast and efficient with a turnover frequency of 1240 s(-1) and an overpotential of only 265 mV for half activity at low acid concentrations. Furthermore, catalysis is possible using a weak acid, and the complex is stable for at least 4 h in acidic solution. Calculations of the system carried out at the density functional level of theory (DFT) are consistent with a mechanism for catalysis in which both protonations take place at the nickel center. PMID:25562523

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

2015-01-28

261

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

SciTech Connect

In order to improve the spectroscopic database for remote sensing of the giant planets, line positions and intensities are determined for the five bands (2?2, ?2 + ?4, 2?4, ?1 and ?3) that comprise the Pentad of PH3 between 1950 and 2450 cm?1. Knowledge of PH3 spectral line parameters in this region is important for the exploration of dynamics and chemistry on Saturn, (using existing Cassini/VIMS observations) and future near-IR data of Jupiter from Juno and ESA’s Jupiter Icy Moons Explorer (JUICE). For this study, spectra of pure PH3 from two Fourier transform spectrometers were obtained: (a) five high-resolution (0.00223 cm?1), high signal-to-noise (?1800) spectra recorded at room temperature (298.2 K) with the Bruker IFS 125HR Fourier transform spectrometer (FTS) at the Pacific Northwest National Laboratory (PNNL), Richland, Washington and (b) four high-resolution (at 0.0115 cm?1 resolution), high signal-to-noise (?700) spectra recorded at room temperature in the region 1800–5200 cm?1 using the McMath-Pierce Fourier transform spectrometer located at the National Solar Observatory (NSO) on Kitt Peak. Individual line parameters above 2150 cm?1 were retrieved by simultaneous multispectrum fittings of all five Bruker spectra, while retrievals with the four Kitt Peak spectra were done in the 1938–2168 cm?1 range spectrum by spectrum and averaged. In all, positions and intensities were obtained for more than 4400 lines. These included 53 A+A? split pairs of transitions (arising due to vibration–rotation interactions (Coriolis-type interaction) between the ?3 and ?1 fundamental bands) for K? = 3, 6, and 9. Over 3400 positions and 1750 intensities of these lines were ultimately identified as relatively unblended and modeled up to J = 14 and K = 12 with rms values of 0.00133 cm?1 and 7.7%, respectively. The PH3 line parameters (observed positions and measured intensities with known quantum assignments) and Hamiltonian constants are reported. Comparisons with other recent studies are discussed.

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

2014-04-01

262

Mechanistic Investigation of Catalytic Carbon-Carbon Bond Activation and Formation by Platinum and Palladium Phosphine  

E-print Network

Mechanistic Investigation of Catalytic Carbon-Carbon Bond Activation and Formation by Platinum impede their development. First, the metal- carbon bond resulting from C-C insertion has been calculated often results in thermal decomposition of the metal complex prior to C-C cleavage. To date, most

Jones, William D.

263

Linear alkaline earth metal phosphinate coordination polymers: synthesis and structural characterization.  

PubMed

Reaction of alkaline earth metal salts with diphenylphosphinic acid in dimethylformamide solvent afforded four coordination polymers: [Mg3(O2PPh2)6(DMF)2]·2DMF (I), [Ca(O2PPh2)2(DMF)2] (II), [Sr(O2PPh2)2(DMF)2] (III) and [Ba(O2PPh2)2(DMF)2] (IV) (where DMF is N,N-dimethylformamide). Single-crystal X-ray diffraction revealed that all four compounds produce linear chain structures in the solid state, with the Ca, Sr and Ba forming isostructural crystals. The bulk materials were characterized by FT-IR and (1)H NMR spectroscopy and elemental analyses. PMID:24892607

Rood, Jeffrey A; Huttenstine, Ashley L; Schmidt, Zachery A; White, Michael R; Oliver, Allen G

2014-06-01

264

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

PubMed Central

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

Brzezi?ska-Rodak, Ma?gorzata

2013-01-01

265

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

PubMed

The reaction of the cyclometalated rollover complex [Pt(bpy-H)(Me)(DMSO)] (bpy-H = cyclometalated 2,2'-bipyridine) with two diphosphines, dppm (1,1-bis(diphenylphosphino)methane) and dppe (1,2-bis(diphenylphosphino)ethane), was investigated. According to the reaction conditions, dppm behaves as a monodentate, bridging or chelated ligand, whereas dppe gave only chelated species. Some aspects of the reactivity of the isolated species were studied, including protonation with [H3O·18-crown-6][BF4] and coordination reactions of mononuclear complexes, obtaining, inter alia, rare examples of unsymmetrical organometallic species with bridging dppm. PMID:25162179

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

2014-10-21

266

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

267

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

2006-05-21

268

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

E-print Network

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

Wu, Xiaoxing

269

Ethyl [1-(4-bromo-phen-yl)-1-hydr-oxy-3-oxobut-yl](phen-yl)phosphinate monohydrate.  

PubMed

In the title hydrate, C(18)H(20)BrO(4)P·H(2)O, a staggered conformation is found when the organic mol-ecule is viewed down the central P-C bond, with the oxo and hydroxyl groups being diagonally opposite; each of the central P and C atoms has an S-configuration. The crystal structure features supra-molecular double chains along the b axis mediated by O(hydrox-yl)-H?O(oxo), O(water)-H?O(oxo), and O(water)-H?O(water) hydrogen bonds. PMID:21580337

Samanta, Sampak; Perera, Sandun; Broker, Grant A; Zhao, Cong-Gui; Tiekink, Edward R T

2010-01-01

270

On the Latitude Variation of Ammonia, Acetylene, and Phosphine Altitude Profiles on Jupiter from HST Faint Object Spectrograph Observations  

Microsoft Academic Search

Ultraviolet spectra in the spectral region from 160 to 230 nm were taken with the Hubble Space Telescope Faint Object Spectrograph in May 1992. We analyze these data to obtain the altitude distribution of ammonia and its variation with latitude from 6°N to 25°N. Ammonia condenses below the 150-mbar level, above which it departs from saturation due to photolysis. Using

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

1998-01-01

271

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

NASA Astrophysics Data System (ADS)

We report blue electrophosphorescent organic light emitting devices with an ambipolar host material, 4-(diphenylphosphoryl)-N ,N-diphenylaniline (HM-A1), doped with FIrpic (iridium (III)bis[(4,6-difluorophenyl)-pyridinato-N,C2']picolinate). The ambipolar nature of the host was verified using single carrier devices. The power efficiency of devices with PO15 (2,8-bis(diphenylphosphoryl)dibenzothiophene) electron transport layer (ETL) showed optimized performance when the ETL thickness was 500 Å, giving a peak power efficiency of 46 lm/W (corresponding external quantum efficiency (EQE) of 17.1%). The EQE 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

272

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

PubMed Central

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

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

2013-01-01

273

P-[N-(Diphenyl­phospho­rothio­yl)iso­propyl­amino]-N-isopropyl-P-phenyl­thio­phosphinic amide  

PubMed Central

The title compound, C24H30N2P2S2, was obtained by the reaction of Ph2PN(iPr)P(Ph)N(iPr)H with elemental sulfur in tetra­hydro­furan. In the solid state, intra­molecular N—H?S hydrogen bonding influences the mol­ecular conformation; a P—N—P—N torsion angle of 2.28?(9)° is observed. The two phenyl rings attached to one P atom form a dihedral angle of 74.02?(4)°. PMID:21583899

Peulecke, Normen; Aluri, Bhaskar R.; Wöhl, Anina; Spannenberg, Anke; Al-Hazmi, Mohammed H.

2009-01-01

274

Reducing CO? to methanol using frustrated Lewis pairs: on the mechanism of phosphine-borane-mediated hydroboration of CO?.  

PubMed

The full mechanism of the hydroboration of CO2 by the highly active ambiphilic organocatalyst 1-Bcat-2-PPh2-C6H4 (Bcat = catecholboryl) was determined using computational and experimental methods. The intramolecular Lewis pair was shown to be involved in every step of the stepwise reduction. In contrast to traditional frustrated Lewis pair systems, the lack of steric hindrance around the Lewis basic fragment allows activation of the reducing agent while moderate Lewis acidity/basicity at the active centers promotes catalysis by releasing the reduction products. Simultaneous activation of both the reducing agent and carbon dioxide is the key to efficient catalysis in every reduction step. PMID:24948159

Courtemanche, Marc-André; Légaré, Marc-André; Maron, Laurent; Fontaine, Frédéric-Georges

2014-07-30

275

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

PubMed

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

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

2014-10-28

276

Transition-metal complexes containing parent phosphine or phosphinyl ligands and their use as precursors for phosphide nanoparticles.  

PubMed

P-H functional transition-metal complexes were synthesized without using hazardous PH3 gas in good yields by photolysis of the transition-metal carbonyl complexes M(CO)(6-x) (M = Cr, W, Fe; x = 0, 1) in tetrahydrofuran followed by reaction with P2(SiMe3)4 and subsequent methanolysis to give the bridging complexes [(CO)(x)M(?-PH2)]2 (M = Fe, x = 3 (1), M = Cr, x = 4 (2a), M = W, x = 4 (2b)). The photolysis of [(CO)4M(?-PH2)]2 (M = Cr (2a), M = W (2b)) with P(SiMe3)3 was applied followed by methanolysis to synthesize the PH2 bridging transition-metal binuclear complexes with terminal PH3 groups. The products [(CO)4M(?-PH2)2M(CO)3(PH3)] (M = Cr (3a), M = W (3b)) and [(CO)4W(?-PH2)2W(CO)2(PH3)2] (4b) were isolated in moderate yield. Another synthetic approach to this type of compounds is the direct photolysis of the complexes [(CO)3M(PH3)3] (M = Cr (5a), M = W (5b)). The products were comprehensively characterized by (31)P NMR and IR spectroscopy as well as by X-ray structural analysis. Additionally, the relevancy of 2a as single source precursor for the synthesis of stoichiometry-controlled CrP nanoparticles has been demonstrated. PMID:25329878

Bauer, Susanne; Hunger, Cornelia; Bodensteiner, Michael; Ojo, Wilfried-Solo; Cros-Gagneux, Arnaud; Chaudret, Bruno; Nayral, Céline; Delpech, Fabien; Scheer, Manfred

2014-11-01

277

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

E-print Network

for the Synthesis of Matrix Metalloproteinase Inhibitors Manishabrata Bhowmick,1 Ravinder R. Sappidi,1 Gregg B at biopolymers@wiley. com INTRODUCTION W e are interested in developing effective matrix metalloproteinase (MMP for the Synthesis of Matrix Metalloproteinase Inhibitors Additional Supporting Information may be found

Lepore, Salvatore D.

278

Facile synthesis of uniform large-sized InP nanocrystal quantum dots using tris( tert-butyldimethylsilyl)phosphine  

NASA Astrophysics Data System (ADS)

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.

Joung, Somyoung; Yoon, Sungwoo; Han, Chang-Soo; Kim, Youngjo; Jeong, Sohee

2012-01-01

279

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

PubMed

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

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

2010-11-14

280

Synthesis of novel fluorinated phosphonic and phosphinic acid electrolytes for phosphoric acid fuel cells. Final report, May 1985-December 1988  

SciTech Connect

New methodology has been developed for the preparation of difluoromethylene phosponate derivatives, perfluorinated bis-phosphonates, and mixed phosphonate-sulfonates. The phosphonates were converted to the respective difluoromethylene phosphonic acids, perfluorinated bis-phosphonic acids, and a mixed fluorinated phosphonic-sulfonic acid. The acids were evaluated as a fuel cell electrolyte. The mono phosphonic acids wetted the Teflon electrode and were found to be unsuitable electrolyte candidates. The bis-phosphonic acids and the mixed phosphonic-sulfonic acid did not wet the Teflon electrode, dissolved more oxygen than phosphonic acid, exhibited excellent thermal stability, and were found to warrant additional study as fuel cell electrolytes.

Burton, D.J.

1989-02-01

281

Size-dependent stability toward dissociation and ligand binding energies of phosphine-ligated gold cluster ions  

SciTech Connect

The stability of sub-nanometer size gold clusters ligated with organic molecules is of paramount importance to the scalable synthesis of monodisperse size-selected metal clusters with highly tunable chemical and physical properties. For the first time, a Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR-MS) equipped with surface induced dissociation (SID) has been employed to investigate the time and collision energy resolved fragmentation behavior of cationic doubly charged gold clusters containing 7-9 gold atoms and 6-7 triphenylphosphine (TPP) ligands prepared by reduction synthesis in solution. The TPP ligated gold clusters are demonstrated to fragment through three primary dissociation pathways: (1) Loss of a neutral TPP ligand from the precursor gold cluster, (2) asymmetric fission and (3) symmetric fission and charge separation of the gold core resulting in formation of complementary pairs of singly charged fragment ions. Threshold energies and activation entropies of these fragmentation pathways have been determined employing Rice-Ramsperger-Kassel-Marcus (RRKM) modeling of the experimental SID data. It is demonstrated that the doubly charged cluster ion containing eight gold atoms and six TPP ligands, (8,6)2+, exhibits exceptional stability compared to the other cationic gold clusters examined in this study due to its large ligand binding energy of 1.76 eV. Our findings demonstrate the dramatic effect of the size and extent of ligation on the gas-phase stability and preferred fragmentation pathways of small TPP-ligated gold clusters.

Johnson, Grant E.; Priest, Thomas A.; Laskin, Julia

2014-08-01

282

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

Microsoft Academic Search

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 (lambdamax~480 nm) with monotonic increase in excimer\\/monomer intensity ratio at higher doping levels within

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

2009-01-01

283

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

284

Intense photo- and tribo-luminescence of three tetrahedral manganese(ii) dihalides with chelating bidentate phosphine oxide ligand.  

PubMed

Three air-stable tetrahedral manganese(ii) dihalide complexes [MnX2(DPEPO)] (DPEPO = bis[2-(diphenylphosphino)phenyl]ether oxide; X = Cl, Br and I) were prepared. All of the obtained compounds were structurally characterized by single-crystal X-ray diffraction analyses, which reveal that they crystallize in centrosymmetric space groups and feature an isolated mononuclear structure with Mn(2+) in a tetrahedral environment. Interestingly, these complexes show excellent photoluminescent performance in neat solid form, with the highest total quantum yield (?total) of up to 70% recorded for the dibromide complex. Intense green flashes of light could be observed by the naked eye when rubbing the manganese(ii) complexes. PMID:25597698

Chen, Jun; Zhang, Qing; Zheng, Fa-Kun; Liu, Zhi-Fa; Wang, Shuai-Hua; Wu, A-Qing; Guo, Guo-Cong

2015-02-01

285

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

E-print Network

, and ^(19)F NMR spectroscopies. In addition, irradiation of [(PNP)Pd-]_(2) under an atmosphere of C_(2)H_(4) produces a mixture of [(PNP)Pd-]_(2) and a ethylene-bridged dinuclear palladium complex ([(PNP)Pd-CH_(2)-]_(2)). If the ethylene headspace is removed...

Huacuja, Rafael

2014-01-17

286

Studies of Soluble Polymer-supported Organocatalysts  

E-print Network

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

Yang, Yun-Chin

2012-10-19

287

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

DOEpatents

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

Alexandratos, Spiro D. (Knoxville, TN)

1987-01-01

288

Cyclometallated platinum(ii) complexes of benzylidene-2,6-di-isopropylphenylamine containing bidentate phosphines: synthesis, structural properties and reactivity studies.  

PubMed

The reaction of the cyclometallated complex [PtCl(N^C)(dmso)], (N^C represents the cyclometallated Schiff base, benzylidene-2,6-diisopropylphenylamine), with 1,1'-bis(diphenylphosphino)ferrocene, dppf, bis(diphenylphosphino)methane, dppm, or 1,2-bis(diphenylphosphino)ethane, dppe, in a 2?:?1 ratio or an equimolar ratio using acetone as the solvent produced the corresponding binuclear or mononuclear diphosphine platinum complexes. In the case of the mononuclear complexes, the diphosphines act as either a bidentate ligand or a monodentate ligand depending on the size of the bite angle of the diphosphines, while in the case of the binuclear complexes, the diphosphines act as a bridging ligand between the two metal centres. The solid state structures of some of the binuclear as well as mononuclear species are reported. The mononuclear derivatives were found to show different behaviour in solution and in the solid state when compared to the binuclear analogues. This behaviour is also influenced by the nature of the diphosphine ligands employed. PMID:25504380

Zheng, Feng; Hutton, Alan T; van Sittert, Cornelia G C E; Gerber, Wilhelmus J; Mapolie, Selwyn F

2014-12-23

289

The Studies of the Phosphine-Initiated General Base-Catalyzed Double-Michael Reaction and the Nitro-Nazarov Reaction.  

E-print Network

??General base-catalyzed double-Michael reactions of allenes with various dinucleophiles are described. The reactions are facilitated most efficiently by a catalytic amount of trimethylphosphine, affording six… (more)

Szeto, Judy

2014-01-01

290

Synthesis, microwave spectrum, quantum chemical calculations, and conformational composition of a novel primary phosphine, cyclopropylethynylphosphine, (C3H5C?CPH2).  

PubMed

The microwave spectrum of cyclopropylethynylphosphine, C3H5C?CPH2, has been investigated in the 26-120 GHz spectral region. The spectrum is dominated by very rich and complex a-type R-branch pile-ups. There must be insignificant steric interaction between the phosphino group and the cyclopropyl ring due to the long distance between these two groups. However, the phosphino group does not undergo free or nearly free internal rotation. Instead, the spectra of two distinct conformers were assigned. Both these two forms have CS symmetry. The symmetry plane bisects the cyclopropyl ring and the phosphino group in both conformers, and the lone electron pair of the phosphino group points in opposite directions in the two rotamers. The energy difference between the two forms was determined to be 1.9(6) kJ/mol. A simple model that takes into consideration the interaction of the lone electron pair of the phosphino group with the ?-electrons of the ethynyl group and the Walsh electrons of the cyclopropyl ring is able to give a qualitative explanation of the observation of two conformers and the nonexistence of free rotation of the phosphino group. The MW work was augmented by quantum chemical calculations using second-order Møller-Plesset perturbation and coupled cluster theory with results that are in good agreement with the experiments. PMID:25170912

Møllendal, Harald; Samdal, Svein; Gauss, Jürgen; Guillemin, Jean-Claude

2014-10-01

291

Crystal structure of a samarium(III) nitrate chain cross-linked by a bis-carbamoyl-methyl-phosphine oxide ligand.  

PubMed

In the title compound poly[aqua-bis-(?-nitrato-?(4) O,O':O,O'')tetra-kis-(nitrato-?(2) O,O'){?4-tetra-ethyl [(ethane-1,2-diyl)bis(aza-nedi-yl)bis-(2-oxo-ethane-2,1-di-yl)]di-phospho-nate-?(2) O,O'}disamarium(III)], [Sm2(NO3)6(C14H30N2O8P2)(H2O)] n , a 12-coordinate Sm(III) and a nine-coordinate Sm(III) cation are alternately linked via shared bis-bidentate nitrate anions into a corrugated chain extending parallel to the a axis. The nine-coordinate Sm(III) atom of this chain is also chelated by a bidentate, yet flexible, carbamoyl-methyl-phoshine oxide (CMPO) ligand and bears one water mol-ecule. This water mol-ecule is hydrogen bonded to nitrate groups bonded to the 12-coordinate Sm(III) cation. The CMPO ligand, which lies about an inversion center, links neighboring chains along the c axis, forming sheets parallel to the ac plane. Hydrogen bonds between the amide NH group and metal-bound nitrate anions are also present in these sheets. The sheets are packed along the b axis through only van der Waals inter-actions. PMID:25484648

Stoscup, Julie A; Staples, Richard J; Biros, Shannon M

2014-10-01

292

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

E-print Network

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

Guenther, Johannes 1983-

2012-08-16

293

Kinetic aspects for the reduction of CO? and CS? with mixed-ligand ruthenium(II) hydride complexes containing phosphine and bipyridine.  

PubMed

A new water-soluble ruthenium hydride complex [Ru(H)(bpy)2(PTA)]PF6 (bpy = 2,2'-bipyridine, PTA = 1,3,5-triaza-7-phosphaadamantane) (1a) was prepared. 1a reacted with CO2 and CS2 to give the corresponding formate and dithioformate complexes, respectively. Both the insertions of CO2 and CS2 into the Ru-H bond of 1a followed second-order kinetics. The second-order rate constant (k2) of CO2 insertion reaction varied from (9.40 ± 0.41) × 10(-4) M(-1) s(-1) in acetone to (1.13 ± 0.08) × 10(-1) M(-1) s(-1) in methanol; moreover, the ln(k2) is in good linear relationship with the acceptor number (AN) of the solvent used. Although, the k2 of CS2 insertion reaction ranged from (3.43 ± 0.10) M(-1) s(-1) in methanol to (24.0 ± 0.5) M(-1) s(-1) in N,N-dimethylformamide, which is 1000 times faster than CO2 insertion. Generally, the k2 of CS2 insertion increased with the static dielectric constant (D(s)) of the reaction medium investigated. For comparison purposes, we further investigated the reactivity of [Ru(H)(bpy)2(PPh3)]PF6 (PPh3 = triphenylphosphine) (1b) with CO2 and CS2. 1b reacted with CO2 slowly in the methanol with a k2 of (1.46 ± 0.09) × 10(-3) M(-1) s(-1), yielding a formate complex [Ru(?(1)-OC(H)?O)(bpy)2(PPh3)]PF6 (2b). The reaction of 1b with CS2 is 1000 times faster than that of CO2. The structures of 1a, 1b, and 2b were determined by X-ray crystallographic analysis. PMID:25167462

Huang, Jing; Chen, Jinzhu; Gao, Hui; Chen, Limin

2014-09-15

294

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

PubMed

Ultra-small PbSe nanocrystals (NCs) were synthesized via a 'one-pot' approach in olive oil as the reaction medium and capping agent. The optical spectra showed discernible blue shifts in the absorption band edges (570-780 nm) due to strong quantum confinement effects and photoluminescence (PL) spectra showed significant strong emission peaks in the range of 780-850 nm. The broad peaks in the powder X-ray diffraction (p-XRD) pattern indicate the ultra-small size of the as-prepared NCs. These NCs were used to construct an extremely thin absorber (ETA) solar device after surface modification. The preliminary results indicate their potential as light harvesting entities in nanostructure based solar cells. PMID:25247625

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

2014-11-21

295

Phosphine-based dinuclear platinum(II) diamido, amido-hydroxo, oxo-amido, oxo-imido, diimido, and dihydroazido complexes  

SciTech Connect

Interest in late transition metal chemistry is focused on the second- and third-row metals Rh, Ir, Pd, Pt, Ag, and Au and primarily involves oxo (O{sup 2{minus}}) complexes. However, the major synthetic route to these complexes involves deprotonation of the corresponding hydroxo (OH{sup {minus}}) and amido (RNH{sup {minus}}) complexes. Thus, the authors are interested in the acid/base chemistry of these conjugate acid/base pairs. In addition, as has been pointed out by Driver and Hartwig, the acid/base properties of the synthetically important alkali metal analogues is fundamental to their chemistry and should be expected to be similarly important for the transition metal complexes. Here the authors report a series of Pt(II) primary aryl amido complexes prepared by aminolysis of the corresponding hydroxo complexes. Deprotonation of these complexes was explored with the goal of increasing the understanding of ancillary ligand effects on the acid/base chemistry of these Pt(II) complexes. The authors have also isolated mixed amido-hydroxo complexes and unique dihydrazido complexes and explored their deprotonation chemistry.

Li, J.J.; Li, W.; James, A.J.; Holbert, T.; Sharp, T.P.; Sharp, P.R. [Univ. of Missouri, Columbia, MO (United States). Dept. of Chemistry] [Univ. of Missouri, Columbia, MO (United States). Dept. of Chemistry

1999-04-05

296

Single-step co-deposition of nanostructured tungsten oxide supported gold nanoparticles using a gold–phosphine cluster complex as the gold precursor  

NASA Astrophysics Data System (ADS)

The use of a molecular gold organometallic cluster in chemical vapour deposition is reported, and it is utilized, together with a tungsten oxide precursor, for the single-step co-deposition of (nanostructured) tungsten oxide supported gold nanoparticles (NPs). The deposited gold-NP and tungsten oxide supported gold-NP are highly active catalysts for benzyl alcohol oxidation; both show higher activity than SiO2 supported gold-NP synthesized via a solution-phase method, and tungsten oxide supported gold-NP show excellent selectivity for conversion to benzaldehyde.

Molkenova, Anara; Sarip, Rozie; Sathasivam, Sanjay; Umek, Polona; Vallejos, Stella; Blackman, Chris; Hogarth, Graeme; Sankar, Gopinathan

2014-12-01

297

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

SciTech Connect

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

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

2009-07-20

298

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

SciTech Connect

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

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

2009-07-20

299

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

E-print Network

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

Girolami, Gregory S.

300

Immobilization of Phosphines on Silica: Identification of Byproducts via 31P CP/MAS Studies of Model Alkyl-, Aryl-, and Ethoxyphosphonium  

E-print Network

- and [R3POEt]+ X- (R ) alkyl, aryl; X ) Cl- , Br- , I- , BF4 - ) and their solid-state NMR characteristics-VCH: Weinheim, Germany, 2000. (2) (a) Seneci, P. Solid-Phase Synthesis and Combinatorial Technologies; John

Bluemel, Janet

301

A radioimmunoassay for SQ 27,519, the active phosphinic acid-carboxylic diacid of the prodrug fosinopril in human serum  

SciTech Connect

Fosinopril (SQ 28,555) is a member of a new chemical class of angiotensin converting enzyme inhibitors being developed by The Squibb Institute for Medical Research. During or following absorption, fosinopril, a prodrug, is hydrolyzed pharmacologically to the active diacid, SQ 27,519. A specific radioimmunoassay (RIA) for the measurement of SQ 27,519 in human serum has been developed. The assay utilizes a specific SQ 27,519 antibody, 125I-iodohistamine-SQ 27,519 radiolabel, and human serum standards. Satisfactory zero binding and assay sensitivity are achieved after a 2-h incubation at room temperature. Separation of the antibody-bound and free radiolabeled antigens is achieved by using polyethylene glycol-goat anti-rabbit gamma globulin separant. Recovery efficiencies ranged from 97.2 to 109.4%. The assay exhibited little or no cross-reactivity with captopril. Cross-reactivities for prodrug (SQ 28,555) and phenolic SQ 27,519 were 5 and 9%, respectively. Intra-assay variability (3.3-5.6%) and interassay variability (7.1-6.6%) were observed. Linear regression analysis indicates that RIA and (14C) thin-layer radiochromatography (TLRC) methods gave a highly significant correlation (RIA = 1.0 (14C)TLRC + 0.17, r = 0.991). Pharmacokinetic profiles of patient sera containing SQ 27,519 obtained by RIA and (14C)TLRC are identical. The RIA has been used routinely in support of the bioavailability and pharmacokinetic studies of fosinopril in humans.

Tu, J.I.; Brennan, J.; Stouffer, B.; Eckelman, W.C. (Bristol-Myers Squibb Company, New Brunswick, NJ (USA))

1990-07-01

302

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

NASA Astrophysics Data System (ADS)

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

Ji, Jeong-Young

303

Effect of low temperatures on the rate of respiration and uptake of phosphine in different life stages of the cigarette beetle Lasioderma serricorne (F.)  

Microsoft Academic Search

Studies were undertaken to establish the effects of low temperatures on the rate of respiration in larvae and adults of a susceptible strain of the cigarette beetle Lasioderma serricorne. The results showed that there was a consistent decrease in the rate of respiration in L. serricorne with a decrease in temperature from 25°C to 5°C. The rate of respiration was

M. Q. Chaudhry; H. A. Bell; N. Savvidou; A. D. MacNicoll

2004-01-01

304

(O,O?-Diethyl dithio­phosphato-?2 S,S?)(hydridotripyrazol-1-ylborato-?3 N 2,N 2?,N 2??)(triphenyl­phosphine-?P)ruthenium(II)  

PubMed Central

Reaction of [Ru(Tp)Cl(PPh3)2] {where Tp is hydridotri­pyrazol­yl­borate, BH[C3H3N2)3)]} with NH4[S2P(OEt)2] in methanol afforded the title compound, [Ru(C9H10BN6)(C4H10O2PS2)(C18H15P)], in which the RuII ion is in a slightly disorted octa­hedral coordination environment. The [S2P(OEt)2]? ligand coordinates in a chelating mode with two similar Ru—S bond lengths and a slightly acute S—Ru—S angle. The atoms of both –OCH2CH3 groups of the diethyl dithio­phosphate ligand are disordered over two sites with approximate occupancies of 0.76 and 0.24. PMID:21580829

Tong, Hung-Chun; Chen Hsu, Chih-Yung; Liang, Yao-Ren; Lo, Yih Hsing; Lin, Chia-Her

2008-01-01

305

Photooxidation of mixed aryl and biarylphosphines.  

PubMed

Arylphosphines and dialkylbiarylphosphines react with singlet oxygen to form phosphine oxides and phosphinate esters. For mixed arylphosphines, the most electron-rich aryl group migrates to form the phosphinate, while for dialkylbiarylphosphines migration of the alkyl group occurs. Dialkylbiarylphosphines also yield arene epoxides, especially in electron-rich systems. Phosphinate ester formation is increased at high temperature, while protic solvents increase the yield of epoxide. The product distribution provides evidence for Buchwald's recent conformational model for the aerobic oxidation of dialkylbiarylphosphines. PMID:20527907

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

2010-07-01

306

Addition compounds of MoO 2Br 2 from MoO 2Br 2(H 2O) 2. Molecular structure of MoO 2Br 2{OP[N(CH 3) 2] 3} 2 and MoO 2Br 2{CH 2[P(O)(C 6H 5) 2] 2}  

Microsoft Academic Search

MoO2Br2L2 (L=dimethyl formamide (DMF), N-methyl pirrolidone (NMP), dimethyl sulfoxide (DMSO), methyl phenyl sulfoxide (MePhSO), diphenyl sulfoxide (Ph2SO), hexamethyl phosphorotriamide (HMPA), triphenyl phosphine oxide (OPPh3), tributhyl phosphine oxide (OPBu3), triocthyl phosphine oxide (OPOct3), methyl diphenyl phosphine oxide (OPMePh2), and 1\\/2 methylene bis(diphenyl phosphine) dioxide (dppmO2)) have been prepared by reacting a solution of MoO2Br2(H2O)2 in diethyl ether with the corresponding ligand.

Francisco J Arnáiz; Rafael Aguado; Mar??a R Pedrosa; José Mah??a; Miguel A Maestro

2002-01-01

307

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

E-print Network

by palladium diphosphine indicate a four-step mechanism: oxidative addition of C6H5Br, migratory insertion of C6H5 to C2H 4, b-hydride transfer/olefin elimination of styrene product, and catalyst regeneration by removal of HBr. For the oxidative addition...

Surawatanawong, Panida

2010-07-14

308

Interaction of Tertiary Phosphines with Acetylenic Compouxds. Alkyl Migration Accompanied by CP Bond Cleavage and Fragmentation During the Interaction of Trialkyphosphines with Phenylacetylene in the Presence of Proton Donors  

Microsoft Academic Search

We have recently describedphosphobetaines with negative charge on ?-carbon atom of vinyl group or on ?-carbon atom of l 1,3-butadienyl group prepared by interaction of trial-kylphosphines with acetylenic and vinylacetylenic compounds, respectively. In the course of developing these investigations an extra route of phosphobetaine formation has been found representing the deprotonation of corresponding phosphonium salts. It has been found that

M. H. Injikian; G. Ts. Gasparian; S. K. Barseghian; M. Zh. Hovakimian

1990-01-01

309

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

PubMed

The complex [7,10-mu-H-7-CO-7,7-(PPh3)2-isonido-7,8,9-ReC2B7H9] has been synthesized by treatment of the complex salt [NHMe3][3,3-Cl2-3,3-(CO)2-closo-3,1,2-ReC2B9H11] with PPh3 in refluxing THF (tetrahydrofuran) and isolated as intensely colored orange-red microcrystals. Spectroscopic NMR and IR data have suggested that the product has a highly asymmetric structure with two inequivalent PPh3 ligands and a single CO ligand. Measurement of 11B NMR spectra in particular have indicated seven distinct boron vertexes, although the resulting cage degradation by removal of two BH vertexes was confirmed only following X-ray crystallographic analysis, which revealed the pentadecahedral isonido-7,8,9-ReC2B7 architecture. The 11B NMR resonances span an enormous chemical shift range (Deltadelta = 113), and this appears to be a direct consequence of the deshielding of the boron vertex directly opposite the quadrilateral |ReCCB| aperture. The new complex has been shown by electrochemical measurements to undergo a reversible one-electron oxidation. Digitally simulated cyclic voltammograms support a proposed square scheme (E(1/2) = 0.58, 0.69 V vs ferrocene) involving a reversible isonido-closo transition of the metallacarborane cage. Most unusually for a metallacarborane complex, ambient temperature solutions in CH2Cl2 and DMF have been shown to be intensely turquoise-blue fluorescent (lambda(em) = 442 nm, Phi = 0.012). Fluorescence spectroscopy measurements in MeTHF (2-methyltetrahydrofuran) glass at 77 K have indicated that the likely cause of such a broad emission is dual fluorescence (lambda(em) = 404, 505 nm), with both emissions displaying vibronic structure. Following excited-state lifetime decay analysis, the emissive behavior has been accredited to metal-perturbed 1IL states, with the lower energy emission arising from a slight geometric distortion of the initially excited complex. PMID:16933936

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

2006-09-01

310

The reaction of triorganophosphorus diiodides, R 3PI 2, with zinc metal powder; dependency of product on R; the X-ray crystal structures of dimeric {ZnI 2[P(NMe 2) 3]} 2 and monomeric ZnI 2(PPh 2Me) 2  

Microsoft Academic Search

Seventeen zinc(II) tertiary phosphine complexes have been synthesised directly from elemental zinc by reaction with the reagents R3PI2. The complexes have been characterised by elemental analysis and 31P{H} NMR spectroscopy. The present work represents the first comprehensive study of a wide variety of zinc(II) tertiary phosphine complexes containing different parent tertiary phosphines and the majority of the complexes are reported

Stephen M Godfrey; Charles A McAuliffe; Robin G Pritchard; Joanne M Sheffield

1999-01-01

311

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

E-print Network

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

Arizpe, Luis (Luis Alfredo)

2011-01-01

312

Asymmetric metal free ?-boration of ?,?-unsaturated imines assisted by (S)-MeBoPhoz.  

PubMed

The adduct [MeO ? Bpin-Bpin](-) efficiently mediates the ?-boration of ?,?-unsaturated imines formed in situ. The use of chiral phosphines as additives, and in particular the chiral phosphine (S)-MeBoPhoz, enables the catalytic asymmetric reaction to proceed with higher enantioselectivity than the analogue copper(i) mediated reaction. PMID:25525774

Cascia, Enrico La; Sanz, Xavier; Bo, Carles; Whiting, Andrew; Fernandez, Elena

2015-01-21

313

Journal of Luminescence 97 (2002) 5559 Blue organic electroluminescent devices based on a  

E-print Network

on a distyrylarylene derivative as emitting layer and a terbium complex as electron-transporting layer Ling Huanga-pyrozolone)-bis(triphenyl phosphine oxide) terbium (Tb(PMIP)3(TPPO)2) as the electron-transporting layer-isobutyryl-5-pyrozolone)-bis(triphenyl phosphine oxide) terbium (Tb(PMIP)3(TPPO)2) possesses high electron

Huang, Yanyi

314

40 CFR 180.284 - Zinc phosphide; tolerances for residues.  

Code of Federal Regulations, 2013 CFR

...for residues of the phosphine resulting from the use of the rodenticide zinc phosphide in or on the raw agricultural commodities...established for residues of phosphine resulting from the use of the rodenticide zinc phosphide in or on the following raw agricultural...

2013-07-01

315

40 CFR 180.284 - Zinc phosphide; tolerances for residues.  

...for residues of the phosphine resulting from the use of the rodenticide zinc phosphide in or on the raw agricultural commodities...established for residues of phosphine resulting from the use of the rodenticide zinc phosphide in or on the following raw agricultural...

2014-07-01

316

40 CFR 180.284 - Zinc phosphide; tolerances for residues.  

Code of Federal Regulations, 2012 CFR

...for residues of the phosphine resulting from the use of the rodenticide zinc phosphide in or on the raw agricultural commodities...established for residues of phosphine resulting from the use of the rodenticide zinc phosphide in or on the following raw agricultural...

2012-07-01

317

Hydroformylation: An Old Yet New Industrial Route to Alcohols.  

ERIC Educational Resources Information Center

Discusses trends in hydroformylation chemistry, considering these catalysis and ligands: (1) cobalt, (2) cobalt-phosphine, and (3) rhodium-phosphine. Indicates that rhodium technology will grow in domination of hydroformylation practice. In addition, processes adapted to special cases of functional olefins and to higher olefins can be expected.…

Pruett, Roy L.

1986-01-01

318

Interaction of some extreme-pressure type lubricating compounds with an iron surface  

NASA Technical Reports Server (NTRS)

An iron surface was exposed to the extreme-pressure type lubricant benzyl chloride, dichlorophenyl phosphine, dichlorophenyl phosphine sulfide, ophenyl phosphine oxide. Iron, in the sputter-cleaned state, was exposed to these materials statically and during dynamic friction experiments. With benzyl chloride only chlorine adsorbed to the surface, and with dichlorophenyl phosphine no adsorption occurred, while the addition of sulfur to that same molecular structure resulted in the promotion of carbon and chlorine adsorption. substitution of oxygen for sulfur in the dichlorobenzyl phosphine molecule resulted in carbon, chlorine, and oxygen adsorption. With none of the phosphorus containing molecules was phosphorus detected on the surface. Sliding in an atmosphere of benzyl chloride promoted adsorption of chlorine to the iron surface. Increases in load resulted in a decrease in the surface concentration of iron chloride.

Buckley, D. H.

1973-01-01

319

Methods for removing contaminant matter from a porous material  

DOEpatents

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

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

2010-11-16

320

Systems and strippable coatings for decontaminating structures that include porous material  

DOEpatents

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

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

2011-12-06

321

Laboratory diagnosis of zinc phosphide poisoning.  

PubMed

Zinc phosphide, a readily-available rodenticide, poses a significant risk for intoxication in animals. Animals have been poisoned by ingesting treated bait or the carcasses of poisoned rodents. Toxicity is due to the liberation of phosphine gas in the stomach. Clinical signs include central nervous system excitation, depression and vomition. Similarities of clinical signs with other central nervous system toxicants make the diagnosis difficult without a specific diagnostic test. The procedure outlined in this paper detects phosphine liberated from zinc phosphide by the addition of hydrochloric acid as well as the phosphine previously generated by contact with stomach acid. PMID:7900268

Guale, F G; Stair, E L; Johnson, B W; Edwards, W C; Haliburton, J C

1994-12-01

322

A DFT and MP2 study of luminescence of gold(I) complexes  

Microsoft Academic Search

Four Au(I) mixed thiolate and phosphine complexes were studied using DFT, TD-DFT, and MP2\\/CIS approaches. Two are mononuclear species, [(R3P)Au(p-SC6H4CH3)] differing by the phosphine (PMe3, 1, or PH3, 1h), to check the use of PH3 in the model. The others were binuclear complexes with bidentate phosphines, bridging two gold atoms, modelled by [Au2(p-SC6H4CH3)2{H2P(CH2)nPH2}] (n=1,2, 2h and 3h, respectively), to assess

Paulo J. Costa; Maria José Calhorda

2006-01-01

323

Marvell NanoLab Member login Lab Manual Contents MercuryWeb Berkeley Microlab Chapter 5.11  

E-print Network

in our LTO (doped & undoped) processes. 5.6 Phosphine (PH3): A gas used in our doped LTO process (PSG). 5 can easily stress and crack the quartz tube. 7.0 Statistical/Process Data Pertinent information can

Healy, Kevin Edward

324

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

PubMed

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

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

2014-12-21

325

Enantioselective carbon–sulfur bond formation: ? additions of aryl thiols to allenoates catalyzed by a chiral phosphepine  

E-print Network

An effective phosphine-catalyzed method was developed for the enantioselective addition of aryl thiols to the ? position of allenoates, thereby providing ready access to aryl alkyl sulfides in very good ee. The array of ...

Fujiwara, Yuji

326

Rhodium-Catalyzed Asymmetric Intramolecular Hydroamination of Unactivated Alkenes  

E-print Network

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

Shen, Xiaoqiang

327

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

E-print Network

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

Spokoyny, Alexander M.

328

Palladium-catalyzed carboxylative coupling of allylstannanes and allyl halides  

SciTech Connect

A three-component carboxylative coupling between allyl halides, allylstannanes, and CO{sub 2} to produce allyl esters is catalyzed by Pd and Pt phosphine complexes. Tentative mechanistic pathways for the catalytic reaction are proposed.

Franks, R.J.; Nicholas, K.M.

2000-04-17

329

Chemoselective ligation  

DOEpatents

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

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

2010-11-23

330

Chemoselective ligation  

DOEpatents

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

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

2011-12-13

331

Chemoselective ligation  

DOEpatents

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

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

2010-02-23

332

Chemoselective ligation  

DOEpatents

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

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

2011-05-10

333

Chemoselective ligation  

DOEpatents

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

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

2011-04-12

334

Chemoselective ligation  

DOEpatents

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

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

2003-05-27

335

What to Do If Your Pet Has Ingested a Rodenticide  

MedlinePLUS

... rodenticide, or if the vomit smells strongly of garlic, evacuate the area and call 911 because the ... dangerous for humans. Phosphine gas smells strongly of garlic. It may cause headache, nausea, stomach pain, diarrhea, ...

336

NEWS OF THE WEEK August 21, 2000  

E-print Network

. Although the first examples of electronic noses have already reached the marketplace, the technology than the detection thresholds of most other electronic nose systems. Besides its low detection limit variety of odorants- -including alcohols, amines, arenes, ethers, halocarbons, ketones, phosphines

Suslick, Kenneth S.

337

Elastomer-modified phosphorus-containing imide resins  

NASA Technical Reports Server (NTRS)

Phosphine oxide-containing polyimide resins modified by elastomers, are disclosed which have improved mechanical properties. These products are particularly useful in the production of fiber or fabric-reinforced composites or laminates.

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

1983-01-01

338

3220 FR.01 Restricted Items Approval Request INSTRUCTIONS  

E-print Network

comments: Arsine Cyanogen Cyanogen chloride Diborane Fluorine Hydrogen cyanide Nitric oxide Nitrogen tetroxide Phosgene Phosphine Cyanide compounds Ethylene oxide Perchloric acid Alkali Metals Barium Lithium Lithium aluminum hydride Phosphorus Potassium Rubidium Sodium Hydrofluoric acidBenzoyl peroxide Mercury

339

Combined (Super 31)P and (Super 1)H NMR Experiments in the Structural Elucidation of Polynuclear Thiolate Complexes  

ERIC Educational Resources Information Center

A facile synthesis of two gold(I) complexes with 1,2-benzenedithiolate ligand and two different bidentate phosphines are described. A detailed sequence of NMR experiments is suggested to determine the structure of the compounds.

Cerrada, Elena; Laguna, Mariano

2005-01-01

340

Decarbonylative cycloaddition of phthalic anhydrides with allenes.  

PubMed

The decarbonylative cycloadditions of phthalic anhydrides with allenes were performed by using nickel catalyst. The asymmetric variant of the cycloaddition was also achieved by using chiral phosphine ligands to provide ?-lactones enantioselectively. PMID:21332138

Ochi, Yosuke; Kurahashi, Takuya; Matsubara, Seijiro

2011-03-18

341

New synthesis method for nickel phosphide hydrotreating catalysts.  

PubMed

Nickel phosphide particles on silica and alumina support were prepared from metal or metal oxide particles by treatment with phosphine and hydrogen at moderate temperature, resulting in small particle sizes equivalent to that of the precursor particle size. PMID:16100595

Yang, Shaofeng; Prins, Roel

2005-09-01

342

Preparation and catalytic hydrogenation properties of some rhodium and ruthenium complexes with chiral tridentate phosphine ligands ( S, S)PhP(CH 2CHMeCH 2PPh 2) 2 and ( S)Ph 2PCH 2CH(PPh 2)CH 2CH 2PPh 2)  

Microsoft Academic Search

Treatment of RhCl(ttp*) (ttp*=(S,S)-PhP(CH2CHMeCH2PPh2)2) with NaBH4 produced Rh(BH4)(ttp*). The reaction of RuCl2(ttp*) with NaBH4 produced RuH(BH4)(ttp*). The complexes RhCl(ttp*), RuCl2(ttp*), Rh(BH4)(ttp*), and RuH(BH4)(ttp*) were found to be catalytically active for the hydrogenation of ?-acetamidocinnamic acid.

Hon Man Lee; Chuluo Yang; Guochen Jia

2000-01-01

343

(eta3-Allyl-2kappa3C)(chloro-1kappaCl)(micro-N,N'-diethyldithioxamidato-1:2kappa4S,S':N,N')[diphenyl(2-pyridyl)phosphine-1kappaP]palladium(II)platinum(II) chloroform solvate.  

PubMed

The title compound, [PdPtCl(C(3)H(5))(C(6)H(10)N(2)S(2))(C(17)H(14)NP)].CHCl(3), was obtained by deprotonation of the initial platinum(II) complex of the dithioxamide and subsequent reaction with [Pd(eta(3)-C(3)H(5))(micro-Cl)](2). Both metal atoms exhibit a square-planar coordination geometry, with the two planes forming a dihedral angle of 21.7 (2) degrees. The dithioxamide bis-chelating bridge is flat. PMID:11983979

Bruno, Giuseppe; Lanza, Santo; Nicoló, Francesco; Tresoldi, Giuseppe; Rosace, Giuseppe

2002-05-01

344

Aluminum phosphide poisoning--a review.  

PubMed

Aluminum phosphide poisoning is common in the rural belt of Northern India. The release of cytotoxic phosphine gas primarily affects the heart, lungs, gastrointestinal tract and kidneys, although all organs can be involved. The cellular site of action of phosphine requires further definition. Diagnosis is made by clinical suspicion, silver nitrate test and biochemical examination of the gastric aspirate and viscera. Treatment consists of early gastric lavage, vasopressors and supportive care. Specific therapy with intravenous magnesium sulphate is recommended. PMID:7837309

Gupta, S; Ahlawat, S K

1995-01-01

345

Asymmetric synthesis of P-stereogenic diarylphosphinites by palladium-catalyzed enantioselective addition of diarylphosphines to benzoquinones.  

PubMed

The reaction of phenyl(2,4,6-trimethylphenyl)phosphine with a substituted benzoquinone in the presence of a chiral phosphapalladacycle complex as a catalyst and triethylamine in chloroform at -45 °C proceeded in a new type of addition manner to give a high yield of a 4-hydroxyphenyl phenyl(2,4,6-trimethylphenyl)phosphinite with 98% enantioselectivity, which is a versatile intermediate readily convertible into various phosphines and their derivatives with high enantiomeric purity. PMID:24635477

Huang, Yinhua; Li, Yongxin; Leung, Pak-Hing; Hayashi, Tamio

2014-04-01

346

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

Microsoft Academic Search

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

Andrzej W. Trochimczuk

2002-01-01

347

Influence of the oxidation state of phosphorus on the decomposition and fire behaviour of flame-retarded epoxy resin composites  

Microsoft Academic Search

A systematic and comparative evaluation of the pyrolysis of halogen-free flame-retarded epoxy resins containing phosphine oxide, phosphinate, phosphonate, and phosphate (phosphorus contents around 2.6wt.%) and the fire behaviour of their carbon fibre composites is presented. Decomposition pathways are proposed based on the thermal analysis (TG), TG coupled with evolved gas analysis (TG-FTIR), kinetics and analysis of the residue with FTIR

Ulrike Braun; Aliaksandr I. Balabanovich; Bernhard Schartel; Uta Knoll; Johannes Artner; Michael Ciesielski; Manfred Döring; Raul Perez; Jan K. W. Sandler; Volker Altstädt; Thorsten Hoffmann; Doris Pospiech

2006-01-01

348

Metal organic vapor phase epitaxy of InAsP\\/InP(001) quantum dots for 1.55 mum applications: Growth, structural, and optical properties  

Microsoft Academic Search

This contribution reports the metal organic vapor phase epitaxy of InAsP\\/InP(001) quantum dots with a voluntary V-alloying obtained owing to an additional phosphine flux during InAs quantum dot growth. The quantum dots were studied by photoluminescence and transmission electron microscopy. We show that the additional phosphine flux allows to tune quantum dot emission around 1.55 mum while improving their optical

A. Michon; R. Hostein; G. Patriarche; N. Gogneau; G. Beaudoin; A. Beveratos; I. Robert-Philip; S. Laurent; S. Sauvage; P. Boucaud; I. Sagnes

2008-01-01

349

The role of cocatalysts in the catalytic nitrogen reduction by sodium amalgam  

SciTech Connect

Polyvinyl alcohol (PVA), phosphatidylcholine (PC), and organic phosphines are cocatalysts of the nitrogen reduction by sodium amalgam in which polynuclear molybdenum complexes serve as catalysts. PVA and PC are adsorbed on the amalgam surface and involve catalytic complexes, thus facilitating their contact with a reducing agent. Phosphines retard the decay of the catalytic centers in the course of the reaction, thus increasing the yield of the reduction products.

Shilova, A.K.; Efimov, O.N.; Makhaev, V.D.; Shilov, A.E. [Institute of Chemical Physics in Chernogolovka, Moscow (Russian Federation)

1995-03-01

350

Synthetic and computational study of geminally bis(supermesityl) substituted phosphorus compounds.  

PubMed

Reaction chemistry of an extremely sterically encumbered phosphinic chloride (Mes*)(2)P(=O)Cl (Mes* = 2,4,6-tri-t-butylphenyl, supermesityl) was investigated. This compound, as well as other compounds bearing two supermesityl groups placed geminally at the central phosphorus atom, shows extremely low reactivity at the phosphorus centre. Nevertheless, some synthetically significant transformations were possible. Reduction with hydridic reagents under forcing conditions yielded the phosphine oxide (Mes*)(2)P(=O)H and a secondary phosphine Mes*(2,4-tBu(2)C(6)H(3))PH. Deprotonation of (Mes*)(2)P(=O)H gave the corresponding phosphinite, which afforded very crowded tertiary phosphine oxides (Mes*)(2)P(=O)R (R = Me and Et) on reactions with electrophiles. While the reaction of the phosphine Mes*(2,4-tBu(2)C(6)H(3))PH with sulfur was surprisingly facile (although under forcing conditions), we have been unable to chlorinate or deprotonate this phosphine. All new compounds were fully characterised with multinuclear NMR, IR, Raman, MS, microanalyses and single crystal X-ray diffraction. Our computations (B3LYP and M06-2X level) show that strain energies of (synthetically accessible) geminally substituted compounds are extremely high (180 to 250 kJ mol(-1)), the majority of the strain is stored as boat distortions to the phenyl rings in Mes* substituents. PMID:23165805

Fleming, Conor G E; Slawin, Alexandra M Z; Athukorala Arachchige, Kasun S; Randall, Rebecca; Bühl, Michael; Kilian, Petr

2013-02-01

351

Synthesis of low color, atomic oxygen resistant polyimides  

NASA Technical Reports Server (NTRS)

The purpose of this project was to develop low color, atomic oxygen resistant polyimides for potential applications on spacecraft in low earth orbit. The material is needed in order to protect satellites and spacecraft from the gases and radiation found at those altitudes. Phosphorous containing polyimides have been shown to be especially resistant to corrosion and weight loss under oxygen plasma. Unfortunately the color of these phosphorous containing polyimides is still too high for them to be good heat insulators. While they are not as effective as teflon, the current material of choice. polyimides are much less dense than teflon and would be especially valuable if they could be made with low color. The approach taken was to synthesize a monomer which would contain the elements needed for giving the final polyimide its desired properties. In particular the monomer should incorporate phosphine or phosphine oxides and have bulky side groups to block any color forming charge transfer structures. The target molecule, 3,5-di-(trifluoromethylphenyl)-bis(3-aminophenyl) phosphine oxide, (containing both a phosphine oxide group and a bulky ditrifluoromethylphenyl group) was synthesized via three reactions in overall yield of 21 percent. In addition, a model compound, bis(3-phenylamine) phenyl phosphine oxide, was synthesized two different ways in order to establish the conditions for the nitration of phosphine oxides and their reduction to the amine. Finally, a trisubstituted phosphine oxide was synthesized. In all, seven phosphorus containing organic compounds were synthesized, purified and characterized. The model compound was reacted with oxydiphthalic anhydride to form a polyamic acid with inherent viscosity of 0.34. This material was cast into a film and heated, forming a normally colored fairly strong polyimide with a Tg of 240 C. The target compound was reacted with 6-fluorodiphthalic anhydride to give a polyamic acid with inherent viscosity of 0.19 and cast to give a heavily cracked colored film with a Tg of 230 C.

MacInnes, Dave

1995-01-01

352

Catalyst- and solvent-dependent stereodivergence in the intramolecular Et(2)Zn/Pd(0) -promoted carbonyl propargylation: mechanistic implications.  

PubMed

Carbonyl-tethered propargylic benzoates undergo intramolecular carbonylpropargylation upon treatment with Et2 Zn in the presence of a catalytic amount of Pd(0) with the formation of 2-alkynylcyclopentanol products. A ligand/solvent effect on the cis/trans selectivity (referring to the relative positions of alkynyl and OH groups) of ring-closure has been found. In a non-coordinating solvent (benzene), increasing the electron-donating ability of the phosphine ligand (while decreasing its dissociation ability) leads to an increased tendency towards the trans product. On the other hand, the combination of a coordinating solvent (THF) and PPh3 , an easily dissociated phosphine, results in the exclusive formation of cis products. Experimental and computational results are compatible with a divergent behavior of an allenylethylpalladium intermediate that partitions between competitive carbonyl-addition and transmetalation pathways, each leading to a different diastereoisomer. These results also suggest that the dissociating ability of the phosphine regulates that behavior. PMID:23963967

Arrate, Mónica; Durana, Aritz; Lorenzo, Paula; de Lera, Ángel R; Álvarez, Rosana; Aurrecoechea, José M

2013-10-01

353

C-P Bond-Forming Reactions via C-O/P-H Cross-Coupling Catalyzed by Nickel.  

PubMed

The first Ni-catalyzed C-O/P-H cross-coupling producing organophosphorus compounds is disclosed. This method features wide generality in regard to both C-O and P-H compounds: for C-O compounds, the readily available alcohol derivatives of aryl, alkenyl, benzyl, and allyl are applicable, and for P-H compounds, both >P(V)(O)H compounds (secondary phosphine oxide, H-phosphinate, and H-phosphonate) and hydrogen phosphines (>P(III)H) can be used as the substrates. Thus, a variety of valuable C(sp(2))-P and C(sp(3))-P compounds can be readily obtained in good to excellent yields by this new strategy. PMID:25629169

Yang, Jia; Chen, Tieqiao; Han, Li-Biao

2015-02-11

354

Heterogeneous catalyst for the production of acetic anhydride from methyl acetate  

DOEpatents

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

Ramprasad, D.; Waller, F.J.

1999-04-06

355

Heterohelicenes with embedded P-chiral 1H-phosphindole or dibenzophosphole units: diastereoselective photochemical synthesis and structural characterization.  

PubMed

The oxidative photocyclization reactions of olefins that contain 1H-phosphindole or dibenzophosphole substituents have been applied to the synthesis of P/N-bi-heterosubstituted dimeric helicenes, as well as of new [6]- and [8]phosphahelicenes. In these photocyclization processes, the configuration of the stereogenic phosphorus center dictates the sense of helical chirality. Thus, by starting from enantiomerically pure P-menthylphosphole-oxide units, this method affords enantiopure helical compounds. The helical phosphine oxides were characterized by X-ray diffraction. After reduction of the phosphine-oxides, the corresponding helical phosphines have been used as ligands in transition-metal complexes. The X-ray crystal structure of a gold chloride complex of a [6]helicene is reported. PMID:23766244

Yavari, Keihann; Retailleau, Pascal; Voituriez, Arnaud; Marinetti, Angela

2013-07-22

356

Heterogeneous catalyst for the production of acetic anhydride from methyl acetate  

DOEpatents

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

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

1999-01-01

357

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

DOEpatents

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

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

2001-01-01

358

High Efficiency InP Solar Cells from Low Toxicity Tertiarybutylphosphine  

NASA Technical Reports Server (NTRS)

Large scale manufacture of phosphide based semiconductor devices by organo-metallic vapor phase epitaxy (OMVPE) typically requires the use of highly toxic phosphine. Advancements in phosphine substitutes have identified tertiarybutylphosphine (TBP) as an excellent precursor for OMVPE of InP. High quality undoped and doped InP films were grown using TBP and trimethylindium. Impurity doped InP films were achieved utilizing diethylzinc and silane for p and n type respectively. 16 percent efficient solar cells under air mass zero, one sun intensity were demonstrated with Voc of 871 mV and fill factor of 82.6 percent. It was shown that TBP could replace phosphine, without adversely affecting device quality, in OMVPE deposition of InP thus significantly reducing toxic gas exposure risk.

Hoffman, Richard W., Jr.; Fatemi, Navid S.; Wilt, David M.; Jenkins, Phillip P.; Brinker, David J.; Scheiman, David A.

1994-01-01

359

Aluminium phosphide-induced leukopenia.  

PubMed

Acute intoxication from the pesticide aluminium phosphide is a relatively rare, life-threatening condition in which cardiovascular decompensation is the most feared problem. We report the case of a patient exposed to aluminium phosphide-liberated phosphine gas. It resulted in the development of a gastroenteritis-like syndrome accompanied by severe reduction in white blood cell numbers as an early and prominent manifestation. By affecting important physiological processes such as mitochondrial function and reactive oxygen species homeostasis, phosphine could cause severe toxicity. After presenting the characteristics of certain leucocyte subpopulations we provide the current molecular understanding of the observed leukopenia which in part seems paradoxical. PMID:24172776

Ntelios, Dimitrios; Mandros, Charalampos; Potolidis, Evangelos; Fanourgiakis, Panagiotis

2013-01-01

360

Unusual complication of aluminum phosphide poisoning: Development of hemolysis and methemoglobinemia and its successful treatment  

PubMed Central

Methemoglobinemia and hemolysis are rare findings following phosphine poisoning. In this paper, a case of aluminum phosphide (AlP) poisoning complicated by methemoglobinemia and hemolysis with a successful treatment is reported. A 28-year-old male patient presented following intentional ingestion of an AlP tablet. In this case, hematuria, hemolysis and methemoglobinemia were significant events. A methemoglobin level of 46% was detected by CO-oximetry. The patient was treated with ascorbic acid and methylene blue and he also received supportive care. Two weeks after admission, the patient was discharged from the hospital. Hemolysis and methemoglobinemia may complicate the course of phosphine poisoning. PMID:21814377

Soltaninejad, Kambiz; Nelson, Leiws S.; Khodakarim, Nastaran; Dadvar, Zohreh; Shadnia, Shahin

2011-01-01

361

Zinc Phosphide Poisoning  

PubMed Central

Zinc phosphide has been used widely as a rodenticide. Upon ingestion, it gets converted to phosphine gas in the body, which is subsequently absorbed into the bloodstream through the stomach and the intestines and gets captured by the liver and the lungs. Phosphine gas produces various metabolic and nonmetabolic toxic effects. Clinical symptoms are circulatory collapse, hypotension, shock symptoms, myocarditis, pericarditis, acute pulmonary edema, and congestive heart failure. In this case presentation, we aim to present the intensive care process and treatment resistance of a patient who ingested zinc phosphide for suicide purposes. PMID:25101186

Do?an, Erdal; Güzel, Abdulmenap; Çiftçi, Taner; Aycan, ?lker; Çetin, Bedri; Kavak, Gönül Ölmez

2014-01-01

362

Unusual complication of aluminum phosphide poisoning: Development of hemolysis and methemoglobinemia and its successful treatment.  

PubMed

Methemoglobinemia and hemolysis are rare findings following phosphine poisoning. In this paper, a case of aluminum phosphide (AlP) poisoning complicated by methemoglobinemia and hemolysis with a successful treatment is reported. A 28-year-old male patient presented following intentional ingestion of an AlP tablet. In this case, hematuria, hemolysis and methemoglobinemia were significant events. A methemoglobin level of 46% was detected by CO-oximetry. The patient was treated with ascorbic acid and methylene blue and he also received supportive care. Two weeks after admission, the patient was discharged from the hospital. Hemolysis and methemoglobinemia may complicate the course of phosphine poisoning. PMID:21814377

Soltaninejad, Kambiz; Nelson, Leiws S; Khodakarim, Nastaran; Dadvar, Zohreh; Shadnia, Shahin

2011-04-01

363

Zinc phosphide poisoning.  

PubMed

Zinc phosphide has been used widely as a rodenticide. Upon ingestion, it gets converted to phosphine gas in the body, which is subsequently absorbed into the bloodstream through the stomach and the intestines and gets captured by the liver and the lungs. Phosphine gas produces various metabolic and nonmetabolic toxic effects. Clinical symptoms are circulatory collapse, hypotension, shock symptoms, myocarditis, pericarditis, acute pulmonary edema, and congestive heart failure. In this case presentation, we aim to present the intensive care process and treatment resistance of a patient who ingested zinc phosphide for suicide purposes. PMID:25101186

Do?an, Erdal; Güzel, Abdulmenap; Ciftçi, Taner; Aycan, Ilker; Celik, Feyzi; Cetin, Bedri; Kavak, Gönül Ölmez

2014-01-01

364

Coordination Chemistry of Cyclic Disilylated Germylenes and Stannylenes with Group 11 Metals  

PubMed Central

Reactions of Et3P adducts of bissilylated germylenes and stannylenes with gold, silver, and copper cyanides led to cyanogermyl or -stannyl complexes of the respective metals. In the course of the reaction the phosphine moved to the metal, while the cyanide migrated to the low-coordinate group 14 element. The respective gold complexes were found to be monomeric, whereas the silver and copper complexes exhibited a tendency to dimerize in the solid state. Attempts to abstract the phosphine ligand with B(C6F5)3 led only to the formation of adducts with the borane coordinating to the cyanide nitrogen atom. PMID:25550678

2014-01-01

365

Electronic tongue — An array of non-specific chemical sensors — For analysis of radioactive solutions  

NASA Astrophysics Data System (ADS)

A variety of novel sensing materials on the basis of phosphine oxides for solvent polymeric sensors have been developed and studied. It was found that phosphine oxide sensors exhibit good sensitivity to rare earth metal cations, such as La3+, Pr3+, Nd3+, Eu3+ and also to Y3+. Polymeric sensors can be comprised into electronic tongue sensor arrays that may allow detection of several rare-earth metal ions simultaneously in mixed solutions. Such sensor arrays are highly promising for environmental and industrial sensing, e.g., for analysis of spent nuclear fuel.

Legin, A.; Kirsanov, D.; Rudnitskaya, A.; Babain, V.

2006-01-01

366

Phosphorus-containing imide resins  

NASA Technical Reports Server (NTRS)

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

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

1983-01-01

367

Phosphorus-containing imide resins  

NASA Technical Reports Server (NTRS)

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

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

1985-01-01

368

Catalytic oxidation by a carboxylate-bridged non-heme diiron complex.  

PubMed

The synthesis of a sterically hindered di(mu-carboxylato)diiron(II) complex bearing terminal N,N',N"-trimethyl-1,4,7-triazacyclononane (Me(3)TACN) ligands and its reaction with dioxygen to afford a (mu-oxo)di(mu-carboxylato)diiron(III) complex are described. Both compounds initiate catalytic oxo transfer with O(2) as the terminal oxidant, converting phosphines to phosphine oxides, dimethyl sulfide to dimethyl sulfoxide, and dibenzylamine to benzaldehyde. Triphenylphosphine is oxidized to triphenylphosphine oxide with a turnover number of >2000 mol.P/mol.cat. PMID:11890772

Tshuva, Edit Y; Lee, Dongwhan; Bu, Weiming; Lippard, Stephen J

2002-03-20

369

Construction of dispirocyclohexanes via amine-catalyzed [2 + 2 + 2] annulations of Morita-Baylis-Hillman acetates with exocyclic alkenes.  

PubMed

Amine-catalyzed [2 + 2 + 2] annulations of one molecule of Morita-Baylis-Hillman (MBH) acetates 1 with two molecules of 2-(arylmethylidene)indane-1,3-diones 2 or methyleneindolinones 4 have been developed under very mild conditions, which produce multistereogenic dispirocyclohexanes 3 and 5, respectively, in moderate to excellent yields and good diastereoselectivity. This amine-catalyzed annulation constitutes a novel and efficient method for the construction of dispirocyclohexane motifs, and also showcases the divergent catalysis between amines and phosphines with regard to the corresponding phosphine-catalyzed [3 + 2] annulations. PMID:25369534

Chen, Rongshun; Xu, Silong; Fan, Xia; Li, Hanyuan; Tang, Yuhai; He, Zhengjie

2015-01-14

370

Catalytic decomposition of phosphorus compounds to produce phosphorus atoms  

NASA Astrophysics Data System (ADS)

Vacuum-ultraviolet laser-induced fluorescence identified atomic phosphorus in the gas phase when phosphine, triethylphosphine, or molecular phosphorus sublimated from solid red phosphorus was decomposed on heated metal wire surfaces. Atomic phosphorus was found to be one of the major products in all systems, and its density increased monotonically with wire temperature but showed saturation at high temperatures. A wire material dependence of density was observed for molecular phosphorus, suggesting that the decomposition of the compound is catalytic. Electron probe microanalyzer (EPMA) measurement showed that the wires are not phosphorized when heated in the presence of phosphine or molecular phosphorus.

Umemoto, Hironobu; Kanemitsu, Taijiro; Kuroda, Yuki

2014-01-01

371

Stereospecific transformation of protected P-H group into P-O or P-N group in one-pot reaction.  

PubMed

A general and efficient procedure for converting 1,1-diethoxyalkylphosphinates into phosphonates or phosphonamides is described by the application of bromine with moderate to high yields and good purity in a one-pot reaction. H-Phosphinate reacts stereospecifically with bromine and subsequently couples with nucleophile to form the corresponding optically active R(1)P(O)(OEt)X with retention of configuration at the phosphorus center. For ?-amino-H-phosphinates, the transformation could be realized without the protection of the amino group. PMID:23121494

Yao, Qiuli; Yuan, Chengye

2012-12-01

372

The rhodium-catalysed 1,2-addition of arylboronic acids to aldehydes and ketones with sulfonated S-Phos  

Microsoft Academic Search

The rhodium-catalysed 1,2-addition of arylboronic acids to aryl aldehydes has been accomplished in high yield using sulfonated S-Phos, a water-soluble biaryl phosphine ligand which allows for catalyst recycling. The catalytic protocol has also been successful in the challenging arylation of ketones.

James R. White; Gareth J. Price; Pawel K. Plucinski; Christopher G. Frost

2009-01-01

373

Spot diagnosis of aluminium phosphide ingestion: an application of a simple test.  

PubMed

Silver nitrate impregnated paper test was performed with the gastric fluid and in breath in 50 patients of aluminium phosphide poisoning. The test was 100% positive with gastric fluid but was positive in 50% patients in breath. The test is simple, reliable and sensitive method to detect phosphine (PH3) for bed side diagnosis of aluminium phosphide (AIP) ingestion. PMID:2768165

Chugh, S N; Ram, S; Chugh, K; Malhotra, K C

1989-03-01

374

Chapter VII-2, Practical Handbook of Photovoltaics: Fundamentals and Applications, General editors T. Markvart and L. Castaner, to  

E-print Network

gallium diselenide (CGS), gallium arsenide (GaAs) and cadmium telluride (CdTe), which are currently, discussion focuses on chemical hazards related to the materials' toxicity, corrosivity, flammability cleaning 2 4 25 - Irritant, Corrosive Phosphine a-Si dopant 0.3 1 50 0.5 Irritant, CNS, GI, flammable

Ohta, Shigemi

375

Marvell NanoLab Member login Lab Manual Contents MercuryWeb Berkeley Microlab Chapter 5.12  

E-print Network

) processes. 5.6 Phosphine (PH3): A gas used in our doped LTO process (PSG). Microlab uses 50% PH3 and 50% Si film) on the furnace wall can easily stress and crack the quartz tube. 7.0 Statistical/Process Data

Healy, Kevin Edward

376

Rhenium and technetium bi- and tricarbonyl complexes in a new strategy for biomolecule incorporation using click chemistry.  

PubMed

A versatile strategy to prepare fac-[M(I)(CO)3](+) and cis-[M(I)(CO)2](+) (M = Re, (99m)Tc) complexes was developed using Huisgen click chemistry and monodentate phosphine ligands to readily incorporate biomolecules and tailor the chemical properties. PMID:24710681

Hayes, Thomas R; Kasten, Benjamin B; Barnes, Charles L; Benny, Paul D

2014-05-21

377

Silver-Mediated Allylic Disulfide Rearrangement for Conjugation of Thiols in Protic Media  

PubMed Central

Alkyl and aryl allyl disulfides are induced to undergo the desulfurative allylic rearrangement by silver nitrate in protic solvents at room temperature, thereby removing the necessity for the use of phosphines as thiophilic reagents. The silver-mediated reaction functions at ambient temperature in protic solvents and in the absence of protecting groups PMID:19911776

Crich, David; Subramanian, Venkataraman; Karatholuvhu, Maheswaran

2009-01-01

378

VACUUM TREATMENTS FOR TREE NUTS  

Technology Transfer Automated Retrieval System (TEKTRAN)

In order to meet consumer demands and export requirements, California tree nuts (walnuts, almonds and pistachios) must be free of insect infestation. Processors have long relied on fumigants such as methyl bromide and phosphine to disinfest their product of field pests such as codling moth and nave...

379

SURFACE AND INTERFACE ANALYSIS Surf. Interface Anal. 2004; 36: 155160  

E-print Network

in the synthesis of phosphine-stabilized gold or other metal nanoparticles.11­15 The phenyl groups in TPP can InterScience (www.interscience.wiley.com). DOI: 10.1002/sia.1675 Synthesis and magnetic properties of e nanoparticles. However, the synthesis of magnetic nanoparticles using TPP as a stabilizer has not been reported

Gao, Hongjun

380

Differential toxicity of antimonial compounds and their effects on glutathione homeostasis in a human leukaemia  

E-print Network

" Differential toxicity of antimonial compounds and their effects on glutathione homeostasis history: Received 14 September 2005 Accepted 26 October 2005 Keywords: Antimonials Macrophage Glutathione species SbIII , trivalent antimony SbV , pentavalent antimony TCEP, tris(2-carboxyethyl) phosphine a b

Schnaufer, Achim

381

Visible light electroluminescent diodes of indium-gallium phosphide  

NASA Technical Reports Server (NTRS)

Vapor deposition and acceptor impurity diffusion techniques are used to prepare indium-gallium phosphide junctions. Certain problems in preparation are overcome by altering gas flow conditions and by increasing the concentration of phosphine in the gas. A general formula is given for the alloy's composition.

Clough, R.; Richman, D.; Tietjen, J.

1970-01-01

382

THE UNIVERSAL SOLVENT EXTRACTION (UNEX) PROCESS. II. FLOWSHEET DEVELOPMENT AND DEMONSTRATION OF THE UNEX PROCESS FOR THE SEPARATION OF CESIUM, STRONTIUM, AND ACTINIDES FROM ACTUAL ACIDIC RADIOACTIVE WASTE  

Microsoft Academic Search

A novel solvent extraction process, the Universal Extraction (UNEX) process, has been developed for the simultaneous separation of cesium, strontium, and the actinides from acidic waste solutions. The UNEX process solvent consists of chlorinated cobalt dicarbollide for the extraction of Cs, polyethylene glycol for the extraction of Sr, and diphenyl-N,N-dibutylcarbamoyl phosphine oxide for the extraction of the actinides and lanthanides.

Jack D. Law; R. Scott Herbst; Terry A. Todd; Valeriy N. Romanovskiy; Vasily A. Babain; Vyatcheslav M. Esimantovskiy; Igor V. Smirnov; Boris N. Zaitsev

2001-01-01

383

THE UNIVERSAL SOLVENT EXTRACTION (UNEX) PROCESS. I. DEVELOPMENT OF THE UNEX PROCESS SOLVENT FOR THE SEPARATION OF CESIUM, STRONTIUM, AND THE ACTINIDES FROM ACIDIC RADIOACTIVE WASTE  

Microsoft Academic Search

A synergistic extraction mixture containing chlorinated cobalt dicarbollide (CCD), carbamoylmethyl phosphine oxide (CMPO), and polyethylene glycol (PEG) has been investigated for the simultaneous recovery of cesium, strontium, lanthanides, and actinides from highly acidic media. The extraction properties of this mixture depend on the concentration ratio of the components. For recovery of all major radionuclides, the optimal ratio of [CCD]:[PEG]: [CMPO

Valeriy N. Romanovskiy; Igor V. Smirnov; Vasily A. Babain; Terry A. Todd; R. Scott Herbst; Jack D. Law; Ken N. Brewer

2001-01-01

384

MAGNETIC RESONANCE IN CHEMISTRY Magn. Reson. Chem. 2003; 41: 406416  

E-print Network

InterScience (www.interscience.wiley.com). DOI: 10.1002/mrc.1183 31 P CP/MAS NMR of polycrystalline; 31 P NMR; CP/MAS; fast spinning; HH matching profiles; immobilized catalysts; immobilized phosphines 2002; Revised 22 January 2003; Accepted 23 January 2003 Cross-polarization (CP) at fast magic angle

Bluemel, Janet

385

Synthesis and physical property characterisation of phosphonium ionic liquids based on P(O) 2(OR) 2 ? and P(O) 2(R) 2 ? anions with potential application for corrosion mitigation of magnesium alloys  

Microsoft Academic Search

Phosphonium cation based ionic liquids (ILs) have become of interest due to their unique chemical and electrochemical stability as well as their promising tribological properties. At the same time, interest has also grown in the use of phosphate and phosphinate based ionic liquids for corrosion protection of reactive metals. In this work we describe the synthesis and characterization of six

Jiazeng Sun; Patrick C. Howlett; Douglas R. MacFarlane; Ji Lin; Maria Forsyth

2008-01-01

386

Issue in Honor of Prof. Pawel Kafarski ARKIVOC 2012 (iv) 264-277 ARKAT-USA, Inc.  

E-print Network

to cyclic aminophosphonic and phosphinic acids David Virieux*, Jean-Noël Volle, and Jean-Luc Pirat* AM2N, the -amino carboxylic acids became with nucleic acids the central molecular bricks of the living organisms.1 In parallel, alkylphosphonic acids were discovered in the Murchison meteorite probably providing a supply

Boyer, Edmond

387

ATP-dependent ligases in trypanothione biosynthesis kinetics of catalysis and inhibition  

E-print Network

1 ,N8 -bis(glutathionyl)spermidine] and trypa- nothione reductase, which replaces not only mechanism for glutathionyl- spermidine synthetase (EC 6.3.1.8) from Crithidia fasciculata (CfGspS) obeys that the phosphinate behaves as a slow-binding bisubstrate inhibitor [competitive with respect to GSH and spermidine

Schnaufer, Achim

388

Development of a Lewis Base Catalyzed Selenocyclization Reaction  

ERIC Educational Resources Information Center

The concept of Lewis base activation of selenium Lewis acids has been effectively reduced to practice in the Lewis base catalyzed selenofunctionalization of unactivated olefins. In this reaction, the weakly acidic species, "N"-phenylselenyl succinimide, is cooperatively activated by the addition of a "soft" Lewis base donor (phosphine sulfides,…

Collins, William

2009-01-01

389

Synthesis and Migratory-Insertion Reactivity of CpMo(CO)[subscript3](CH[subscript3]): Small-Scale Organometallic Preparations Utilizing Modern Glovebox Techniques  

ERIC Educational Resources Information Center

Experiments are described for the reliable small-scale glovebox preparation of CpMo(CO)[subscript 3](CH[subscript 3]) and acetyl derivatives thereof through phosphine-induced migratory insertion. The robust syntheses introduce students to a variety of organometallic reaction mechanisms and glovebox techniques, and they are easily carried out…

Whited, Matthew T.; Hofmeister, Gretchen E.

2014-01-01

390

Stepwise activation of "non-innocent" Cp* substituents--a Cp* based cascade reaction.  

PubMed

Reactions of Cp* substituted pentelidene complexes with the primary phosphine Cp*PH(2) yield novel polycyclic phosphorus/arsenic and carbon containing cage compounds via cascade-like reactions. These reactions include a sequence of nucleophilic addition reactions, intramolecular hydrophosphination (partially hydroarsination) reactions, retro-Diels-Alder reactions with Cp*H elimination and subsequent [2+4]-cycloadditions. PMID:22699410

Stubenhofer, Markus; Lassandro, Giuliano; Balázs, Gábor; Timoshkin, Alexey Y; Scheer, Manfred

2012-07-25

391

A versatile methodology for the synthesis of alpha,beta-unsaturated 3-iminophosphines.  

PubMed

Phorteen phine phosphines: Fourteen new alpha,beta-unsaturated beta-chloroimines were synthesized from inexpensive ketones by using the Vilsmeier-Haack reagent followed by Schiff-base condensation. Each imine was subsequently converted to an alpha,beta-unsaturated 3-iminophosphine through either late-metal-catalyzed phosphorus-carbon cross-coupling or through an addition-elimination sequence (see scheme). This high-yield protocol serves as a general means to produce alpha,beta-unsaturated 3-iminophosphines.Fourteen new alpha,beta-unsaturated beta-chloroimines were synthesized from commercially available ketones using the Vilsmeier-Haack reagent, followed by Schiff-base condensation. Each imine was subsequently converted to an alpha,beta-unsaturated 3-iminophosphine through either late-metal-catalyzed phosphorus-carbon cross-coupling or through an addition-elimination sequence. Depending on the substituents present on the vinyl group, the resultant phosphines were isolated as either E or Z diastereomers with successful isolation of predominately single diastereomers for all fourteen new phosphines investigated. Full synthetic and spectroscopic details, as well as several X-ray crystal structures of these new imines and phosphines, are reported in addition to X-ray crystal structures of related palladium complexes. PMID:19180602

Shaffer, Andrew R; Schmidt, Joseph A R

2009-03-01

392

Research Opportunities 2014-15 Professor Malcolm Halcrow Professor Malcolm Halcrow  

E-print Network

catecholate groups, that can each bind a metal ion. The platinum complex in the Figure exhibits three. Hardie and M. A. Halcrow, `Stable mixed-valent radicals from platinum(II) complexes of a bis-dioxolene ligand', Chem. Eur. J., 2014, in the press. Crystal structure of a platinum/phosphine complex containing

Rzepa, Henry S.

393

Silyl-migrations in frustrated Lewis pair chemistry: reactions of ((CH3)3Si)3P and B(C6F4H)3 with H2 and CO2.  

PubMed

The 1 : 1 mixture of tris(trimethylsilyl)phosphine and tris(2,3,5,6-tetrafluorophenyl)borane behaves as frustrated Lewis pair (FLP) and shows H(2) and sequential two-step double CO(2) activation with subsequent Me(3)Si group transfer. PMID:23072756

Takeuchi, Katsuhiko; Stephan, Douglas W

2012-11-28

394

The Isomerization Equilibrium between Cis and Trans Chloride Ruthenium Olefin Metathesis Catalysts from Quantum Mechanics Calculations  

E-print Network

The Isomerization Equilibrium between Cis and Trans Chloride Ruthenium Olefin Metathesis Catalysts strongly coordinating phosphines with weakly bound oxygen- or nitrogen-containing ligands.5 These ruthenium.14 The 1s-3d core electrons of the ruthenium atom were described with the Hay and Wadt core

Goddard III, William A.

395

Synthetic and structural study of the coordination chemistry of a peri-backbone-supported phosphino-phosphonium salt.  

PubMed

Coordination chemistry of an acenaphthene peri-backbone-supported phosphino-phosphonium chloride (1) was investigated, revealing three distinct modes of reactivity. The reaction of 1 with Mo(CO)4(nor) gives the Mo(0) complex [(1)Mo(CO)4Cl] (2), in which the ligand 1 exhibits monodentate coordination through the phosphine donor and the P-P bond is retained. PtCl2(cod) reacts with the chloride and triflate salts of 1 to form a mononuclear complex [(1Cl)PtCl2] (3) and a binuclear complex [((1Cl)PtCl)2][2TfO] (4), respectively. In both of these complexes, the platinum center adds across the P-P bond, and subsequent chloride transfer to the phosphenium center results in phosphine-chlorophosphine bidentate coordination. [((1)PdCl)2] (5) was isolated from the reaction of 1 and Pd2(dba)3 (dba = dibenzylideneacetone). Oxidative addition to palladium(0) results in a heteroleptic phosphine bridging phosphide coordination to the Pd(II) center. In addition, reaction of 1 with BH3·SMe2 leads to the bis(borane) adduct of the corresponding mixed tertiary/secondary phosphine (6), with BH3 acting as both a reducing agent and a Lewis acid. The new compounds were fully characterized, including X-ray diffraction. The ligand properties of 1 and related bonding issues are discussed with help of DFT computations. PMID:25073081

Ray, Matthew J; Bühl, Michael; Taylor, Laurence J; Athukorala Arachchige, Kasun S; Slawin, Alexandra M Z; Kilian, Petr

2014-08-18

396

40 CFR 721.10370 - Phosphonic acid, p-octyl-, lanthanum (3+) salt (2:1).  

Code of Federal Regulations, 2012 CFR

...false Phosphonic acid, p-octyl-, lanthanum (3+) salt (2:1). 721.10370...10370 Phosphonic acid, p-octyl-, lanthanum (3+) salt (2:1). (a) Chemical...identified as phosphinic acid, p-octyl-, lanthanum (3+) salt (2:1) (PMN...

2012-07-01

397

Bifunctionalized allenes. Part XIII. A convenient and efficient method for regioselective synthesis of phosphorylated ?-hydroxyallenes with protected and unprotected hydroxy group.  

PubMed

The paper describes a convenient and efficient method for regioselective synthesis of phosphorylated ?-hydroxyallenes using an atom economical [2,3]-sigmatropic rearrangement of intermediate propargyl phosphites or phosphinites. These can be readily prepared via reaction of protected alkynols with dimethyl chlorophosphite or chlorodiphenyl phosphine respectively in the presence of a base. PMID:24840901

Ismailov, Ismail E; Ivanov, Ivaylo K; Christov, Valerij Ch

2014-01-01

398

The 1982 NASA/ASEE summer faculty fellowship research program, abstracts of research projects, 1st and 2nd-year fellows  

NASA Technical Reports Server (NTRS)

Phosphine photolysis in Jupiter's atmosphere is discussed in relation to organic chemical evolution. Workload in AFTI F-16 test flights, infrared observations of M17, and the relation between rock and vegetation types are presented. Orbiter transfer vehicle aerothermodynamics simulation problems are also discussed.

1982-01-01

399

40 CFR 721.10370 - Phosphonic acid, p-octyl-, lanthanum (3+) salt (2:1).  

Code of Federal Regulations, 2013 CFR

...Phosphonic acid, p-octyl-, lanthanum (3+) salt (2:1). 721.10370 Section 721...Phosphonic acid, p-octyl-, lanthanum (3+) salt (2:1). (a) Chemical substance...phosphinic acid, p-octyl-, lanthanum (3+) salt (2:1) (PMN P-10-99; CAS...

2013-07-01

400

40 CFR 721.10370 - Phosphonic acid, p-octyl-, lanthanum (3+) salt (2:1).  

...Phosphonic acid, p-octyl-, lanthanum (3+) salt (2:1). 721.10370 Section 721...Phosphonic acid, p-octyl-, lanthanum (3+) salt (2:1). (a) Chemical substance...phosphinic acid, p-octyl-, lanthanum (3+) salt (2:1) (PMN P-10-99; CAS...

2014-07-01

401

HPLC-UV determination of total vitamin C in a wide range of fortified food products  

Microsoft Academic Search

A HPLC method for the quantification of total ascorbic acid (AA) and isoacorbic acid (isoAA) in fortified food products, premixes and duomixes has been developed. The method is based on the acidic extraction of AA in the presence of reducing agent Tris [2-carboxyethyl] phosphine (TCEP), which maintained AA in its reduced form. The separation was performed on a C18 column

Patric Fontannaz; Tamara Kilinç; Olivier Heudi

2006-01-01

402

Photochemistry of intermolecular C-H bond activation reactions  

SciTech Connect

Goals at the onset were to obtain photophysical and photochemical data on transition-metal organometallic complexes which undergo light-induced intermolecular C-H bond activation reactions with hydrocarbon substrates. The complexes included these of rhodium and rhenium with such as cyclopentadiene, CO, phosphine, pyridines, etc.

Lees, A.J.

1994-09-01

403

On the Phosphorus Characterization in Thin SiO2(P, B) CVD Layer Deposited onto a Silicon Substrate by PIXE  

E-print Network

On the Phosphorus Characterization in Thin SiO2(P, B) CVD Layer Deposited onto a Silicon Substrate that the phosphorus concentration in the CVD layer varies linearly with the percentage of the phosphine gas used in the CVD gas mixture. Keywords : PIXE, Low Energy PIXE, CVD, Phosphorus, SiO2, Thin layers * Correspondence

Boyer, Edmond

404

Poly(ethylene glycol) as reaction medium for mild Mizoroki-Heck reaction in a ball-mill.  

PubMed

Phosphine-free palladium-catalyzed Mizoroki-Heck reaction was performed using ball-milling in polyethylene glycol under mild conditions. Good to excellent yields of coupling products were obtained. This activation technique also allowed the concomitant formation of round shaped Pd-PEG nanoparticles that were characterized by TEM analysis. PMID:23104100

Declerck, Valérie; Colacino, Evelina; Bantreil, Xavier; Martinez, Jean; Lamaty, Frédéric

2012-12-14

405

Plasma deposition of amorphous metal alloys  

DOEpatents

Amorphous metal alloy coatings are plasma-deposited by dissociation of vapors of organometallic compounds and metalloid hydrides in the presence of a reducing gas, using a glow discharge. Tetracarbonylnickel, phosphine, and hydrogen constitute a typical reaction mixture of the invention, yielding a NiPC alloy.

Hays, Auda K. (Albuquerque, NM)

1986-01-01

406

Organophosphorus esters causing delayed neurotoxic effects  

Microsoft Academic Search

Mechanism o\\/Action. Evidence is reviewed that the initial biochemical event leading to delayed neurotoxicity is phosphorylation of the active site of a specific enzyme called Neurotoxie Esterase. This is followed by a bondclcavage ( ? hydrolytic) leading to formation of a mono-substituted phosphoric acid residue on the protein. The mechanism by which some phosphinates protect hens against neurotoxic compounds is

M. K. Johnson

1975-01-01

407

Merging Gold and Organocatalysis: A Facile Asymmetric Synthesis of Annulated Pyrroles  

PubMed Central

The combination of cinchona-alkaloid-derived primary amine and AuI–phosphine catalysts allowed the selective C–H functionalization of two adjacent carbon atoms of pyrroles under mild reaction conditions. This sequential dual activation provides seven-membered-ring-annulated pyrrole derivatives in excellent yields and enantioselectivities. PMID:24590817

Hack, Daniel; Loh, Charles C. J.; Hartmann, Jan M.; Raabe, Gerhard; Enders, Dieter

2014-01-01

408

Fields Institute Communications Volume 30, 2001  

E-print Network

of the inversion line observed upon increase of the pressure in a gas of ammonia or deuterated ammonia. The same for example ammonia N H 3 , deuterated ammonia N D3 , phosphine P H3 and arsine AsH3. We begin by presenting and times, we can perform some adiabatic approximations. The electronic motion can be separated from

Presilla, Carlo

409

Dried Fruits and Nuts  

Technology Transfer Automated Retrieval System (TEKTRAN)

Current control of postharvest insect pests of dried fruits and tree nuts relies heavily on fumigants such as methyl bromide or phosphine. There is mounting pressure against the general use of chemical fumigants due to atmospheric emissions, safety or health concerns, and an increased interest in or...

410

Permeation of metal ions through hollow-fiber supported liquid membranes: concentration equations for once-through and recycling module arrangements  

SciTech Connect

Concentration equations are presented for the permeation of metal ions through hollow-fibers supported liquid membranes (SLMs). The equations have been tested for the transport of H/sup +/ and Am/sup 3 +/ through SLMs containing trilaurylamine and an alkylphenylcarbamoylmethyl-phosphine oxide as ion carriers.

Danesi, P.R.

1984-01-01

411

PERMEATION OF METAL IONS THROUGH HOLLOW-FIBER SUPPORTED LIQUID MEMBRANES: CONCENTRATION EQUATIONS FOR ONCE-THROUGH AND RECYCLING MODULE ARRANGEMENTS  

Microsoft Academic Search

Concentration equations are presented for the permeation of metal ions through hollow-fibers supported liquid membranes (SLMs). The equations have been tested for the transport of H\\/sup +\\/ and Am\\/sup 3 +\\/ through SLMs containing trilaurylamine and an alkylphenylcarbamoylmethyl-phosphine oxide as ion carriers.

P. R. Danesi

1984-01-01

412

Merging gold and organocatalysis: a facile asymmetric synthesis of annulated pyrroles.  

PubMed

The combination of cinchona-alkaloid-derived primary amine and Au(I) -phosphine catalysts allowed the selective C-H functionalization of two adjacent carbon atoms of pyrroles under mild reaction conditions. This sequential dual activation provides seven-membered-ring-annulated pyrrole derivatives in excellent yields and enantioselectivities. PMID:24590817

Hack, Daniel; Loh, Charles C J; Hartmann, Jan M; Raabe, Gerhard; Enders, Dieter

2014-04-01

413

Synthesis of cationic iridium(I) complexes of water-soluble phosphine ligands, [Ir(CO)(TPPMS){sub 3}]CF{sub 3}SO{sub 3}, [Ir(CO)(H{sub 2}O)(TPPTS){sub 2}]CF{sub 3}SO{sub 3}, and [Ir(CO){sub 2}(TPPMS){sub 3}]ClO{sub 4} (TPPMS = PPh{sub 2}(m-C{sub 6}H{sub 4}SO{sub 3}K), TPPTS = P(m-C{sub 6}H{sub 4}SO{sub 3}Na){sub 3})  

SciTech Connect

Several new water-soluble iridium(I) complexes were synthesized and their reactivities with small molecules (H{sub 2} or CO) in polar solvents (DMSO or H{sub 2}O) examined. Reaction of H{sub 2} with [Ir(CO)(TPPMS){sub 3}]CF{sub 3}SO{sub 3} (TPPMS = P(C{sub 6}H{sub 5}){sub 2}(m-C{sub 6}H{sub 4}SO{sub 3}K)) in DMSO or H{sub 2}O produces [cis,mer-Ir(CO)(H){sub 2}(TPPMS){sub 3}]CF{sub 3}SO{sub 3}, while the reaction of CO with [Ir(CO)(TPPMS){sub 3}]-CF{sub 3}SO{sub 3} in water yields [Ir(CO){sub 2}(TPPMS){sub 3}]CF{sub 3}SO{sub 3}. Carbonylation of [Ir(CO){sub 2}(TPPMS){sub 3}]ClO{sub 4} in DMSO produces [Ir(CO){sub 3}(TPPMS){sub 2}]ClO{sub 4} and TPPMS; no reaction is observed in H{sub 2}O. Hydrogenation of [Ir(CO){sub 2}(TPPMS){sub 3}]ClO{sub 4} in DMSO or H{sub 2}O yields [cis,mer-Ir(CO)(H){sub 2}(TPPMS){sub 3}]ClO{sub 4}, while reaction of H{sub 2} with an aqueous solution of [Ir(CO)(H{sub 2}O)(TPPTS){sub 2}]CF{sub 3}SO{sub 3} produces [Ir(CO)(H{sub 2}O)(H){sub 2}(TPPTS){sub 2}]CF{sub 3}SO{sub 3}. Reaction of trans-Ir(CO)ClL{sub 2} (L = TPPMS or TPPTS) with excess L in H{sub 2}O produces [Ir(CO)L{sub 3}]Cl, while no reaction occurs in DMSO, [Ir(CO){sub 3}(TPPMS){sub 2}]Cl reacts irreversibly with TPPMS in H{sub 2}O to produce [Ir(CO){sub 2}-(TPPMS){sub 3}]Cl.

Paterniti, D.P.; Francisco, L.W.; Atwood, J.D. [State Univ. of New York, Buffalo, NY (United States). Dept. of Chemistry] [State Univ. of New York, Buffalo, NY (United States). Dept. of Chemistry

1999-01-18

414

High-nuclearity close-packed palladium-nickel carbonyl phosphine clusters : hesteropalladium [Pd{sub 16}Ni{sub 4}(CO){sub 22}(PPh{sub 3}){sub 4]{sup 2-} and [Pd{sub 33}Ni{sub 9}(CO){sub 41}(PPh{sub 3}){sub 6}]{sup 4-} containing Pseudo-T{sub d} ccp Pd{sub 16}Ni{sub 4} and Pseudo-D{sub 3h} hcp Pd{sub 33}Ni{sub 9} cores.  

SciTech Connect

[Pd{sub 16}Ni{sub 4}(CO){sub 22}(PPh{sub 3}){sub 4}]{sup 2-} (1) and [Pd{sub 33}Ni{sub 9}(CO){sub 41}(PPh{sub 3}){sub 6}]{sup 4-} (2) were obtained as the two major products from the reduction of PdCl{sub 2}(PPh{sub 3}){sub 2} with [Ni{sub 6}(CO){sub 12}]{sup 2-}. Their crystal structures as [PPh{sub 4}]{sup +} salts were unambiguously determined from CCD X-ray crystallographic analyses; the resulting stoichiometries were ascertained from elemental analyses. Infrared, multinuclear {sup 1}H, {sup 31}P{l_brace}{sup 1}H{r_brace} NMR, UVvis, CV, variable-temperature magnetic susceptibility, and ESI FT/ICR mass spectrometric measurements were performed. The Pd{sub 16}Ni{sub 4} core of 1 ideally conforms to a ccp {nu}{sub 3} tetrahedron of pseudo-T{sub d} ({sub {ovr 4}}3m) symmetry. Its geometry normal to each tetrahedral Pd7Ni3 face (i.e., along each of the four 3-fold axes) may be viewed as a four-layer stacking of 20 metal atoms in a ccp [a(Ni{sub 1}) b(Pd{sub 3}) c(Pd{sub 6}) a(Pd{sub 7}Ni{sub 3})] sequence. A comparative analysis of the different ligand connectivities about the analogous metal-core geometries in 1 and the previously reported [Os{sub 20}(CO){sub 40}]{sup 2-} has stereochemical implications pertaining to the different possible modes of carbon monoxide attachment to ccp metal(111) surfaces. The unique geometry of the Pd{sub 33}Ni{sub 9} core of 2, which has pseudo-D{sub 3h} ({sub {ovr 6}}2m) symmetry, consists of five equilateral triangular layers that are stacked in a hcp [a(Pd{sub 7}Ni{sub 3}) b(Pd{sub 6}) a(Pd{sub 7}Ni{sub 3}) b(Pd{sub 6}) a(Pd{sub 7}Ni{sub 3})] sequence. Variable-temperature magnetic susceptibility measurements indicated both 1 and 2 to be diamagnetic over the entire temperature range from 5.0 to 300 K. Neutral Pd{sub 12}(CO){sub 12}(PPh{sub 3}){sub 6} (3) and [Pd{sub 29}(CO){sub 28}(PPh{sub 3}){sub 7}]{sup 2-} (4) as the [PPh{sub 4}]{sup +} salt were obtained as minor decomposition products from protonation reactions of 1 and 2, respectively, with acetic acid. Compound 3 of pseudo-D{sub 3d} ({sub {ovr 3}}2/m) symmetry represents the second highly deformed hexacapped octahedral member of the previously established homopalladium family of clusters containing uncapped, monocapped, bicapped, and tetracapped Pd6 octahedra. The unprecedented centered 28-atom polyhedron for the Pd{sub 29} core of 4 of pseudo-C{sub 3v} (3m) symmetry may be described as a four-layer stacking of 29 metal atoms in a mixed hcp/ccp [a(Pd{sub 1}) b(Pd{sub 3}) a(Pd{sub 10}) c(Pd{sub 15})] sequence.

Kawano, M.; Bacon, J. W.; Campana, C. F.; Winger, B. E.; Dudek, J. D.; Sirchio, S. A.; Scruggs, S. L.; Geiser, U.; Dahl, L. F.; Univ. of Wisconsin at Madison; Bruker Analytical X-Ray Instruments; Finnigan FT /MS Corp.

2001-05-21

415

Bis(pentamethylcyclopentadienyl)ytterbium: An investigation of weak interactions in solution using multinuclear NMR spectroscopy  

SciTech Connect

NMR spectroscopy is ideal for studying weak interactions (formation enthalpy {le}20 kcal/mol) in solution. The metallocene bis(pentamethylcyclopentadienyl)ytterbium, Cp*{sub 2}Yb, is ideal for this purpose. cis-P{sub 2}PtH{sub 2}complexes (P = phosphine) were used to produce slow-exchange Cp*{sub 2}YbL adducts for NMR study. Reversible formation of (P{sub 2}PtH){sub 2} complexes from cis-P{sub 2}PtH{sub 2} complexes were also studied, followed by interactions of Cp*{sub 2}Yb with phosphines, R{sub 3}PX complexes. A NMR study was done on the interactions of Cp*{sub 2}Yb with H{sub 2}, CH{sub 4}, Xe, CO, silanes, stannanes, C{sub 6}H{sub 6}, and toluene.

Schwartz, D.J.

1995-07-01

416

A double fatality with children due to fumigated wheat.  

PubMed

Two children, four and two years old, played on top of wheat, that had been fumigated with malathion, pyrethrum and phosphine. Both died within 18 hours. Because after the autopsy, death could not be attributed to any organic or violent cause, a toxicological analysis was carried out. No drugs, except alcohol, was detected. Those results were attributed to hydrolysis of malathion, yielding two molecules of ethanol. As this was an indirect proof of malathion ingestion, it was assumed that phosphine had been ingested as well and that consequently this was the cause of death, because it is much more toxic than malathion and because it was continuously generated from not completely dissolved aluminiumphosphide tablets, while the children were still playing. PMID:1278248

Heyndrickx, A; Van Peteghem, C; Van Den Heede, M; Lauwaert, R

1976-01-01

417

2-(Diphenyl­phosphinoylmeth­yl)pyrrole–2-(diphenyl­phosphinometh­yl)pyrrole (0.43/0.57) and tetra­chlorido­(5-diphenyl­phosphinometh­yl-2H-pyrrole-?2 N,P)titanium(IV)  

PubMed Central

The title phosphine oxide–phosphine, 0.43C17H16NOP·0.57C17H16NP, (I)/(II), was obtained as a 0.861?(6):1.139?(6) cocrystallized mixture. Hydrogen bonding between the two constituents leads to the formation of 2:2 solid-state assemblies. Instead of forming the expected simple N,P-chelated system via loss of the N-bound H atom, reaction of 2-(diphenyl­phosphinometh­yl)pyrrole, (II), with TiCl4 leads to the formation of the title titanium(IV) complex, [TiCl4(C17H16NP)], (IV), containing a rearranged neutral ligand in which the N-bound H atom moves to one of the pyrrole C atoms, giving a partially unsaturated ring. PMID:20203400

Broomfield, Lewis M.; Bochmann, Manfred; Wright, Joseph A.

2010-01-01

418

When the Tolman electronic parameter fails: a comparative DFT and charge displacement study of [(L)Ni(CO)?](0/-) and [(L)Au(CO)](0/+).  

PubMed

In this study we have examined 42 [(L)M(CO)n](±/0) complexes (M = Ni and Au), including neutral ligands, such as phosphines and carbenes, and anionic ones. For each complex, the carbonyl stretching frequency (?(CO)) and the amount of charge donated from the ligand to the metal (CT) have been computed on the basis of DFT calculations. For nickel complexes, the two observables nicely correlate with each other, as expected from the theory underlying the Tolman electronic parameter. On the contrary, for gold complexes a more complex pattern can be observed, with an apparent differentiation between phosphine ligands and carbon-based ones. Such differences have been explained analyzing the Au-L bond in terms of Dewar-Chatt-Duncanson bonding constituents (? donation and ? back-donation). Our analysis demonstrates that in linear gold(I) complexes, ?(CO) depends only on the metal-to-ligand ? back-donation. PMID:25166741

Ciancaleoni, Gianluca; Scafuri, Nicola; Bistoni, Giovanni; Macchioni, Alceo; Tarantelli, Francesco; Zuccaccia, Daniele; Belpassi, Leonardo

2014-09-15

419

A General Approach To Fabricate Fe3 O4 Nanoparticles Decorated with Pd, Au, and Rh: Magnetically Recoverable and Reusable Catalysts for Suzuki C?C Cross-Coupling Reactions, Hydrogenation, and Sequential Reactions.  

PubMed

A facile strategy has been explored for loading noble metals onto the surface of ferrite nanoparticles with the assistance of phosphine-functionalized linkers. Palladium loading is shown to occur with participation of both the phosphine function and the surface hydroxyl groups. Hybrid nanoparticles containing simultaneously Pd and Au (or Rh) are obtained by successive loading of metals. Similarly, ferrite nanoparticles decorated with Pd, Au, and Rh have also been formed by using the same strategy. The catalytic properties of the new nanoparticles are evidenced in processes such as reduction of 4-nitrophenol or hydrogenation of styrene. Besides, the sequential process involving a cross-coupling reaction followed by reduction of 1-nitrobiphenyl has been successfully achieved by employing Pd/Au decorated nanoferrite particles. PMID:23868578

Gonzàlez de Rivera, Ferran; Angurell, Inmaculada; Rossell, Marta D; Erni, Rolf; Llorca, Jordi; Divins, Núria J; Muller, Guillermo; Seco, Miquel; Rossell, Oriol

2013-07-18

420

Feasibility of actinide separation from UREX-like raffinates using a combination of sulfur- and oxygen-donor extractants  

SciTech Connect

A synergistic combination of bis(o-trifluoromethylphenyl)dithios-phosphinic acid and trioctylphosphine oxide has been recently shown to selectively remove uranium, neptunium, plutonium and americium from aqueous environment containing up to 0.5 M nitric acid and 5.5 g/l fission products. Here the feasibility of performing this complete actinide recovery from aqueous mixtures is forecasted for a new organic formulation containing sulfur donor extractant of modified structure based on Am(III) and Eu(III) extraction data. A mixture of bis(bis-m,m-trifluoromethyl)phenyl)-dithios-phosphinic acid and TOPO in toluene enhances the extraction performance, accomplishing Am/Eu differentiation in aqueous mixtures up to 1 M nitric acid. The new organic recipe is also less susceptible to oxidative damage resulting from radiolysis. (authors)

Zalupski, P.R.; Peterman, D.R.; Riddle, C.L. [Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83415 (United States)

2013-07-01

421

Trace Species Identified in Saturn's Northern Storm Region  

NASA Technical Reports Server (NTRS)

The massive storm at 40degN on Saturn that began in December 2010 has produced significant and lasting effects in the northern hemisphere on temperature and species abundances [I}. The northern storm region was observed at 0.5/cm spectral resolution in March 2011 by Cassini's Composite Infrared Spectrometer (CIRS). Temperatures in the stratosphere as high as 190 K were derived from CIRS spectra in warm regions referred to as "beacons". Other longitudes exhibit cold temperatures in the upper troposphere. These unusual conditions allow us to identify rare species such as C4H2, C3H4, and CO2 in the stratosphere, as well as to measure changes in the abundance of phosphine (PH3) in the troposphere. Phosphine is a disequilibrium species whose abundance is a tracer of upwelling from the deep atmosphere.

Bjoraker, Gordon L.; Hesman, B. E.; Achterberg, R. K.

2011-01-01

422

Coordination Chemistry of Cyclic Disilylated Stannylenes and Plumbylenes to Group 4 Metallocenes  

PubMed Central

Reduction of group 4 metallocene dichlorides with magnesium in the presence of cyclic disilylated stannylene or plumbylene phosphine adducts yielded the respective metallocene tetrylene phosphine complexes. Under the same conditions the use of the respective dimerized stannylene or plumbylene gave metallocene ditetrylene complexes. A computational analysis of these reactions revealed for all investigated compounds multiple-bonded character for the M–E(II) linkage, which can be rationalized in the case of the monotetrylene complex with the classical ?-donor/?-acceptor interaction. The strength of the M–E(II) bond increases descending group 4 and decreases going from Sn to its heavier congener Pb. The weakness of the Ti–E(II) bonds is caused by the significantly reduced ability of the titanium atom for d–p ?-back-bonding. PMID:22716501

2012-01-01

423

Group 5 hydride and borohydride complexes supported by cyclopentadienyl-imido ligand sets.  

PubMed

Reactions of Cp*Ta(NAr)Cl2 and CpM(NAr)Cl2 (M = Nb, Ta; Ar = 2,6-C6H3(i)Pr2) with NaBH4 in the presence of an excess of PMe3 provided facile access to the corresponding dihydride derivatives Cp(R)M(NAr)H2(PMe3) (Cp(R) = Cp, Cp*). Reaction of Cp*Nb(NAr)Cl2 with NaBH4 in the absence of phosphine gave the Nb(+5) borohydride-hydride complex Cp*Nb(NAr)H(?(2)-BH4). When the corresponding reactions for CpM(NAr)Cl2 (M = Nb, Ta) were carried out in the absence of an excess of phosphine, dimeric M(IV) products [CpM(?-NAr)(?(2)-BH4)]2 containing M-M single bonds were formed. PMID:24131994

McLeod, Nicolas A; Kuzmina, Lyudmila G; Churakov, Andrei V; Mountford, Philip; Nikonov, Georgii I

2014-01-01

424

Controlling charge transport in blue organic light-emitting devices by chemical functionalization of host materials  

SciTech Connect

Generation of white light from OLEDs for general lighting applications requires a highly efficient blue component. However, a stable and power efficient blue OLED component with simple device architecture remains a significant challenge partly due to lack of appropriate host materials. Here we report the photophysical and device properties of ambipolar host phosphine oxide based materials. In this work, we studied the effect of the structural modification made to phosphine oxide-based hosts on the charge balance. We observed significant changes in charge transport within the host occurred upon small modifications to their chemical structure. As a result, an alteration of the chemical design of these materials allows for the control of charge balance of the OLED.

Polikarpov, Evgueni; Koech, Phillip K.; Wang, Liang; Swensen, James S.; Cosimbescu, Lelia; Rainbolt, James E.; Von Ruden, Amber L.; Gaspar, Daniel J.; Padmaperuma, Asanga B.

2011-01-18

425

On the compensation mechanism of amorphous silicon films: Study of stability  

SciTech Connect

The authors investigated a-Si:H compensated materials deposited over a wide range of gas dopant concentrations, from 0.125 ppm up to 10{sup 3} ppm. They achieved compensation for different ratio in the gas phase of diborane and phosphine, depending on their concentration. As a relevant result, they found that at constant boron concentration compensation occurs by using two different values of phosphine flow. This behavior can be described by a change of formation mechanism involving active dopants, defects and boron-phosphorus complex, that occurs in a different way depending on the dopant concentrations. The two compensation regimes are evidenced also by a different behavior under light soaking. Furthermore they found that photocurrent evolution under illumination is determined by two concurrent mechanisms: activation of dopant species and increase of defect density.

Caputo, D.; De Cesare, G.; Palma, F.; Tucci, M.; Minarini, C.; Terzini, E.

1997-07-01

426

Easy-separable magnetic nanoparticle-supported Pd catalysts: Kinetics, stability and catalyst re-use  

Microsoft Academic Search

A series of novel palladium-based catalysts supported on magnetic nanoparticles with diameters of 7–17nm have been prepared and evaluated in C–C coupling, hydrogenation and amination reactions. One type of catalyst used palladium complexes containing phosphine and\\/or acetate ligands for applications in Suzuki and Heck reactions. The second type consisted of Pd(0)-functionalised magnetic cores for use in hydrogenation and C–C coupling.

Urszula Laska; Christopher G. Frost; Gareth J. Price; Pawel K. Plucinski

2009-01-01

427

Adult respiratory distress syndrome following aluminium phosphide ingestion. Report of 4 cases.  

PubMed

Four cases of adult respiratory distress syndrome (ARDS) following aluminium phosphide ingestion (ALP) are being reported. The dose of the intoxicant varied from 2 tablets (6.0 gm) to 3 tablets (9.0 gm). All patients had shock at admission and developed ARDS within 6 hours. The exhalation of Phosphine, (PH3) detected by positive silver nitrate paper test, was the possible noxious triggering factor in our cases. The cases are being reported because of their rare occurrence. PMID:2613620

Chugh, S N; Ram, S; Mehta, L K; Arora, B B; Malhotra, K C

1989-04-01

428

Subendocardial infarction in a young survivor of aluminium phosphide poisoning.  

PubMed

Aluminium phosphide is a solid fumigant pesticide and has systemic toxicity due to liberation of phosphine gas. We report a case of aluminium phosphide poisoning with systemic toxicity in a 16-year-old patient who developed previously undocumented complication of subendocardial infarction, with characteristic electrocardiographic changes reverting back to normal after a period of 10 weeks, even though the patient had clinical recovery much earlier. PMID:17623772

Kaushik, Rajeev M; Kaushik, Reshma; Mahajan, Sukhdev K

2007-05-01

429

Preconcentration and separation of copper, nickel and zinc in aqueous samples by flame atomic absorption spectrometry after column solid-phase extraction onto MWCNTs impregnated with D2EHPA-TOPO mixture  

Microsoft Academic Search

A solid phase extraction method has been developed for the determination of copper, nickel and zinc ions in natural water samples. This method is based on the adsorption of copper, nickel and zinc on multiwalled carbon nanotubes (MWCNTs) impregnated with di-(2-ethyl hexyl phosphoric acid) (D2EHPA) and tri-n-octyl phosphine oxide (TOPO). The influence of parameters such as pH of the aqueous

S. Vellaichamy; K. Palanivelu

2011-01-01

430

Surface accumulation of hydrogen during capless annealing of InP  

SciTech Connect

InP samples, which had received a capless anneal in a phosphine/hydrogenatmosphere, were examined for hydrogen contamination by secondary-ion massspectrometry. It is found that hydrogen accumulates at the InP surface duringannealing. Annealing of Be-implanted InP leads to similar profile shapes for theBe and H atoms. Passivation of the Be acceptors, if effective at all, appears tobe of only minor significance.

Haussler, W.

1989-06-19

431

Marvell NanoLab Member login Lab Manual Contents MercuryWeb Berkeley Microlab Chapter 5.10  

E-print Network

gas used for deposition of poly-Si. 5.3 Phosphine (PH3): A gas used to dope the polysilicon film. The Nanolab uses a 50% PH3 and 50% SiH4 mixture for safety. 5.4 ROP: Remote-Operation Panel 5.5 ALMACK : Alarm are typically around 615ºC. Do not run the tube at temperatures above 650ºC, as it may crack the tube, which has

Healy, Kevin Edward

432

An enantioselective total synthesis of helioporins C and E.  

PubMed

A short and enantioselective total synthesis of helioporins C and E, which are bioactive marine diterpenes containing a serrulatane or amphilectane skeleton, was elaborated. The chirogenic step, i.e. a Cu(I)-catalyzed allylic alkylation of a cinnamyl chloride with methylmagnesium bromide, proceeded with virtually complete enantioselectivity (99% ee) in the presence of a chiral phosphine-phosphite ligand. The other stereocenters were diastereoselectively established through Me(2)AlCl-mediated cationic cyclization and Ir-catalyzed hydrogenation. PMID:23148527

Lölsberg, Wibke; Werle, Susen; Neudörfl, Jörg-Martin; Schmalz, Hans-Günther

2012-12-01

433

Highly diastereoselective palladium-catalyzed indium-mediated allylation of chiral hydrazones.  

PubMed

The general and efficient palladium-catalyzed indium-mediated allylation of chiral hydrazones was accomplished with excellent yield (72-92%) and diastereoselectivity (up to 99:1). The development of this reaction and the substrate scope are described. The conversion was found to be proportional to the phosphine concentration, which provided insight into the mechanism and competing pathways of the redox transmetalation process. PMID:25565466

Balasubramanian, Narayanaganesh; Mandal, Tanmay; Cook, Gregory R

2015-01-16

434

Synthesis and Properties of Sub50-nm Europium Oxide Nanoparticles  

Microsoft Academic Search

Eu2O3 nanocrystals are synthesized by a colloidal precipitation route in the size range 2–40 nm. The nanocrystals are passivated with a surface layer of trioctyl phosphine oxide (TOPO) in order to eliminate surface recombination effects. When pumped at 254 nm (4f ? 5d transition) the nanocrystals exhibit red luminescence characteristic of 5D0 ? 7Fn Eu3+ transitions within the cubic form

G. Wakefield; H. A. Keron; P. J. Dobson; J. L. Hutchison

1999-01-01

435

Improved ozonolysis method for analysis of total n?3 fatty acids during hydrogenation of fish oils  

Microsoft Academic Search

A rapid and precise method for determining the total amount of n?3 fatty acids in small samples of fish oil is presented.\\u000a The oil is ozonized at ?10C in hexane solution, and the ozonides are subsequently reduced with triphenyl-phosphine at 40C.\\u000a The propanal formed is quantitated by capillary gas chromatography. The method was utilized to follow the industrial hydrogenation\\u000a of

Laila S. Jacobsen; Aage Jart

1994-01-01

436

Phosphorus concentration profiles in p-doped silicon dioxide measured using Auger spectroscopy  

Microsoft Academic Search

The depth distribution of phosphorus in silicon dioxide formed by reacting phosphine and silane with oxygen at 480°C, has been measured with Auger spectroscopy using (i) ramp-etched silicon dioxide films and (ii) in situ ion milling. Quantitative Auger analysis showed the phosphorus concentration to be 0.5 at.% throughout most of the oxide. However, when grown directly on silicon, a phosphorusrich

C. C. Chang; A. C. Adams; G. Quintana; T. T. Sheng

1974-01-01

437

ATOMIC-RESOLUTION STUDY OF OVERLAYER FORMATION AND INTERFACIAL MIXING IN THE INTERACTION OF PHOSPHORUS WITH SI(001)  

Microsoft Academic Search

Scanning tunneling microscopy (STM), tunneling spectroscopy, and Auger-electron spectroscopy have been used to study the formation of phosphorus-terminated silicon (001) surfaces by the thermal decomposition of phosphine (PH3). The STM images show that surface phosphorus atoms readily displace Si from the substrate, dramatically changing the overall surface morphology through the formation of large numbers of islands and an extreme roughening

Yajun Wang; Xiangxiong Chen; Robert Hamers

1994-01-01

438

Secondary phosphinocarbyne and phosphaisonitrile complexes.  

PubMed

The palladium-mediated reaction of [W(?CBr)(CO)2(Tp*)] (Tp* = hydrotris(3,5-dimethylpyrazol-1-yl)borate) with primary phosphines PH2R (R = Ph, Cy) affords the secondary phosphinocarbyne complexes [W(?CPHR)(CO)2(Tp*)], deprotonation of which provides the anionic phosphaisonitrile complexes [W(CPR)(CO)2(Tp*)](-), including the structurally characterized salt [W(CPPh)(CO)2(Tp*)][K(kryptofix)]. PMID:25470387

Colebatch, Annie L; Hill, Anthony F

2014-12-17

439

Expedient asymmetric synthesis of all four isomers of N,N'-protected 2,3-diaminobutanoic acid.  

PubMed

2,3-Diaminobutanoic acid (DAB) is found in several peptide antibiotics, toxins, and biologically active molecules. This paper describes the practical and highly enantioselective synthesis of all four N,N'-protected DAB stereoisomers using an asymmetric Rh(I)-phosphine-catalyzed hydrogenation of isomeric enamides as the key step. Thermal and photochemical isomerization of the enamide hydrogenation substrates coupled with catalyst-geometric isomer pairing allows targeted synthesis of single DAB isomers in maximum yield. PMID:11397146

Robinson, A J; Stanislawski, P; Mulholland, D; He, L; Li, H Y

2001-06-15

440

Selective reduction of peptide isothiazolidin-3-ones.  

PubMed

Isothiazolidinones are a rare but potentially important chemical moiety in biochemistry. We report the identification of several thiol, phosphinate, and carbon nucleophiles that form covalent adducts by addition to the sulfenamide sulfur. This reduction is selective for isothiazolidinones over similar peptide disulfides. We synthesized a coumarin-based thioacid nucleophile which shows a marked fluorescence increase after addition to an isothiazolidinone sulfenamide bond. [structure: see text] PMID:17134250

Shiau, Timothy P; Erlanson, Daniel A; Gordon, Eric M

2006-12-01

441

Asymmetric Dual-Reagent Catalysis: Mannich-type Reactions Catalyzed by Ion Pair.  

PubMed

The combination of a new bifunctional phosphine and an acrylate generate a zwitterion in?situ and it serves as an efficient catalyst for asymmetric reactions through a homogeneous ion-pairing mode. This new catalytic system has been successfully applied to Mannich-type reactions to give excellent results and it demonstrates a broad substrate scope. Such reactivity is not accessible with general organophosphine catalytic modes. Preliminary investigations into the mechanism are also presented. PMID:25515428

Wang, Hong-Yu; Zhang, Kai; Zheng, Chang-Wu; Chai, Zhuo; Cao, Dong-Dong; Zhang, Jia-Xing; Zhao, Gang

2015-02-01

442

Ruthenium(II) arene complexes with oligocationic triarylphosphine ligands: Synthesis, DNA interactions and in vitro properties  

Microsoft Academic Search

The synthesis, DNA binding properties and cytotoxicity of a series of Ru(II)-arene complexes containing oligocationic ammonium-functionalized triarylphosphines, of the type Ru(p-cymene)Cl2(L) (L = oligocationic phosphine), are reported. The complexes are highly charged (the overall charge states being +3 and +6) and circular dichroism spectroscopy and gel electrophoresis studies indicate that the compounds interact strongly with DNA via electrostatic interactions. Despite forming strong

Dennis J. M. Snelders; Angela Casini; Fabio Edafe; Gerard van Koten; Robertus J. M. Klein Gebbink; Paul J. Dyson

2011-01-01

443

Solvent Extraction of Actinides and Lanthanides by CMP(O)? and N?Acyl(thio)urea?tetrafunctionalized Cavitands: Strong Synergistic Effect of Cobalt Bis(dicarbollide) Ions  

Microsoft Academic Search

The synthesis of two carbamoylmethylphosphate (CMP)? and ?phosphine oxide (CMPO)?tetrafunctionalized cavitands with a propyl spacer between the cavitand platform and the chelating sites is described. Liquid–liquid extractions with CMP(O)?and N?acyl(thio)urea?tetrafunctionalized cavitands were performed from aqueous nitric acid into dichloromethane or o?nitrophenyl hexyl ether (NPHE). The extraction of americium (III) and europium (III) from aqueous nitric acid into NPHE was studied

Willem Verboom; David N. Reinhoudt; Fre´deric Brisach; Karine Liger

2005-01-01

444

Synthesis of hcp-Co nanodisks  

SciTech Connect

hcp Co disk-shaped nanocrystals were obtained by rapid decomposition of cobalt carbonyl in presence of linear amines. Other surfactants, in addition to the amines, like phosphine oxides and oleic acid were used to improve size dispersion, shape control and nanocrystal stability. Co disks are ferromagnetic in character and they spontaneously self-assemble into long ribbons. X-ray and electron diffraction, electron microscopy and SQUID magnetometry have been employed to characterize this material.

Puntes, Victor F.; Zanchet, Daniela; Erdonmez, Can K.; Alivisatos, A.P.

2002-06-11

445

A NOVEL APPROACH TO CATALYTIC DESULFURIZATION OF COAL  

SciTech Connect

A gas chromatographic method has been developed for the quantitation of sulfur removed from coal as tributyl phosphine sulfide (SPBu{sub 3}). This method also works very well for speciating and quantitating the products of sulfur removal from organosulfur removal from organosulfur compounds such as dibenzothiophene. Remarkably mild conditions have been discovered for quantitative sulfur removal from dibenzothiophene and other organosulfur systems using relatively cheap elemental sodium.

John G. Verkade

2000-10-01

446

V o l . 5 3 , P P . 2 8 7 -2 9 2 ' I 98I . Printed in Great  

E-print Network

'{SOF THERMALDECOMPOSITION PLATINUI''I( I I) COMPLEXES' RESULTS The dialkylbis (phosphine)platinum(I I) complexes preparedTiast with the obser.,,ation that intermolecular c-H addition to platinum is s10w' P o s s i b l e r e a s o n s f o r by platinum meta1. These reactions are generally believed Io invo1""-;i;;i.rr* r,rtiace a1k.,-1s',tut neither

Prentiss, Mara

447

Mechanism and Activity of Ruthenium Olefin Metathesis Catalysts  

Microsoft Academic Search

This report details the effects of ligand variation on the mechanism and activity of ruthenium-based olefin metathesis catalysts. A series of ruthenium complexes of the general formula L(PR3)(X)2RudCHR 1 have been prepared, and the influence of the substituents L, X, R, and R 1 on the rates of phosphine dissociation and initiation as well as overall activity for olefin metathesis

Melanie S. Sanford; Jennifer A. Love; Robert H. Grubbs

2001-01-01

448

Phosphathiahelicenes: synthesis and uses in enantioselective gold catalysis.  

PubMed

Enantiomerically pure thiahelicenes displaying a terminal phosphole unit and a stereogenic phosphorus center have been prepared by oxidative photocyclization of a diaryl-olefin precursor. Starting from one of these phosphathiahelicene oxides, the corresponding trivalent phosphine-Au(I) complex is obtained with complete diastereoselectivity. It affords a new, excellent precatalyst for the enantioselective cycloisomerization of N-tethered enynes (up to 96?% ee). PMID:25113927

Aillard, Paul; Voituriez, Arnaud; Dova, Davide; Cauteruccio, Silvia; Licandro, Emanuela; Marinetti, Angela

2014-09-22

449

One-pot synthesis of 2,4-disubstituted indoles from N-tosyl-2,3-dichloroaniline using palladium-dihydroxyterphenylphosphine catalyst.  

PubMed

4-Chloroindoles were synthesized from readily available 2,3-dichloroaniline derivatives and terminal alkynes. The catalyst composed of palladium and dicyclohexyl(dihydroxyterphenyl)phosphine (Cy-DHTP) enabled ortho-selective Sonogashira coupling, and subsequent cyclization afforded 4-chloroindoles in high yields. This transformation was successfully applied to the one-pot synthesis of 2,4-disubstituted indoles via Suzuki-Miyaura coupling after indole formation. PMID:24742051

Yamaguchi, Miyuki; Manabe, Kei

2014-05-01

450

Mn(OAc)3-mediated phosphonation-lactonization of alkenoic acids: synthesis of phosphono-?-butyrolactones.  

PubMed

A new, general method for the synthesis of phosphono-?-butyrolactones has been achieved through Mn(OAc)3-mediated radical oxidative phosphonation and lactonization of alkenoic acids with H-phosphonates and H-phosphine oxide. Mn(OAc)3 can be readily prepared from Mn(OAc)2 in the laboratory. This transformation allows the direct formation of a P-C bond and the construction of a lactone ring in one reaction. PMID:25500623

Gao, Yuzhen; Li, Xueqin; Xu, Jian; Wu, Yile; Chen, Weizhu; Tang, Guo; Zhao, Yufen

2015-01-15

451

Preconcentration and Separation of Uranium from Thorium by Solid Phase Extraction with XAD?4 Modified with Organic Reagents  

Microsoft Academic Search

Uranyl ion can be separated from aqueous solution and preconcentrated on XAD?4 modified with organic reagents. Dibenzoyl methane (DBM), 8?hydroxy quinoline (oxine), and tri?n?octyl phosphine oxide (TOPO) were impregnated on the adsorber resin and treated with aqueous solutions containing microgram quantity of uranium. The preconcentrated uranium could be eluted out with dilute acid from the column modified with DBM or

K. Venkatesh; B. Maiti

2005-01-01

452

Enynylation of 2-iodo-4-(phenylchalcogenyl)-1-butenes via intramolecular chelation: approach to the synthesis of conjugated dienynes or trienynes.  

PubMed

[reaction: see text] 2-Iodo-4-(phenylchalcogenyl)-1-butenes 3 and 4, which are derived from methylenecyclopropanes 1, can be enynylated with alkynes catalyzed by Pd(OAc)(2) to give conjugated dienynes 5 and 6 in the absence of any phosphine ligand and copper salt, and trienyne 9a can be obtained by oxidation of compound 5a. A plausible reaction mechanism has been proposed. PMID:15987211

Shi, Min; Liu, Le-Ping; Tang, Jie

2005-07-01

453

Breaking the ring through a room temperature catalytic Wittig reaction.  

PubMed

One ring no longer rules them all: Employment of 2.5-10?mol?% of 4-nitrobenzoic acid with phenylsilane led to the development of a room temperature catalytic Wittig reaction (see scheme). Moreover, these enhanced reduction conditions also facilitated the use of acyclic phosphine oxides as catalysts for the first time. A series of alkenes were produced in moderate to high yield and selectivity. PMID:23526683

O'Brien, Christopher J; Lavigne, Florie; Coyle, Emma E; Holohan, Andrew J; Doonan, Bryan J

2013-05-01

454

A Novel and Convenient Synthesis of E,E-bis(Styryl) sulfones and E,E-1,4Diaryl1,3-butadienes  

Microsoft Academic Search

The condensation of 2-phenylethanesulfonylacetic acid (4) with araldehydes (5) in presence of a base gave E-styryl-2-phenylethyl sulfones (6) which on dehydrogenation with DDQ (7) yielded E,E-bis-(styrl)sulfones (8). The 8 on treatment with dichlorotris(triphenyl-phosphine)ruthenium(II) catalyst resulted 1,4-diaryl-1,3-butadienes (9). The configurations of 6, 8 and 9 have been determined based on IR and H NMR spectral data.

M. V. Ramana Reddy; A. B. Manjubhashini; S. Reddy; P. V. Ramana Reddy; D. Baskar Reddy

1991-01-01

455

Phosphorus-containing imide resins  

NASA Technical Reports Server (NTRS)

Flame-resistant reinforced bodies are disclosed which are composed of reinforcing fibers, filaments or fabrics in a cured body of bis- and tris-imide resins derived from tris(m-aminophenyl) phosphine oxides by reaction with maleic anhydride or its derivatives, or of addition polymers of such imides, including a variant in which a mono-imide is condensed with a dianhydride and the product is treated with a further quantity of maleic anhydride.

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

1984-01-01

456

Modelling small gold and silver nanoparticles with electronic structure methods  

Microsoft Academic Search

Electronic structure methods, especially density functional theory (DFT) and time-dependent DFT, have found significant applications in understanding the structure and properties of nanoparticles. In this review, recent studies of the geometric and electronic structure, optical absorption, circular dichroism, growth mechanisms, ligand exchange mechanisms and other properties of thiolate-protected and phosphine-protected gold and silver nanoparticles are discussed in relation to our

Christine M. Aikens

2012-01-01

457

Electronic structure studies of six-atom gold clusters  

Microsoft Academic Search

Combined theoretical and experimental studies of the hexagold phosphine-stabilized complex [Au6(PPh3)6][BF4]2 (1) and of related systems are reported. The goal of these studies is to gain a better understanding of how 1 interacts with the TiO2(110) substrate to yield finely dispersed supported Au particles that are effective for practical catalytic reactions. The experimental efforts involved the measurement of the visible-ultraviolet

Mohammad A. Omary; Manal A. Rawashdeh-Omary; Charles C. Chusuei; John P. Fackler; Paul S. Bagus

2001-01-01

458

Characterization of large cationic transition-metal-gold clusters by fast atom bombardment mass spectroscopy (FABMS). New Re-Au and Pt-Au clusters: (AuâRe(H)â(P(p-tol)â)â(PPhâ)â)\\/sup +\\/, (AuâReâ(H)â(PPhâ)â)\\/sup +\\/, and (AuâPt(PPhâ)â)\\/sup 2 +  

Microsoft Academic Search

Fast atom bombardment mass spectroscopy has been used to examine a large number of cationic phosphine-containing transition-metal-fold clusters including polyhydrides, which ranged in mass from 1000 to 4000. Many of these clusters have been previously characterized and were examined in order to test the usefulness of the FABMS technique. Results showed that FABMS is excellent in giving the correct molecular

P. D. Boyle; B. J. Johnson; B. D. Alexander; J. A. Casalnuovo; P. R. Gannon; S. M. Johnson; E. A. Larka; A. M. Mueting; L. H. Pignolet

1987-01-01

459

Rate and mechanism of facilitated americium(III) transport through a supported liquid membrane containing a bifunctional organophosphorus mobile carrier  

Microsoft Academic Search

The facilitated transport of Am(III) from aqueous nitrate solutions to formic acid aqueous solutions through a supported liquid membrane (SLM) is described. The supported liquid membrane consists of a solution of a new (carbamoylmethyl)phosphine oxide in diethylbenzene (DEB) absorbed into a 48 ..mu..m thick microporous polypropylene film. The transport mechanism consists of a diffusion process through an aqueous diffusion film,

P. R. Danesi; E. P. Horwitz; P. G. Rickert

1983-01-01

460

A study of the separation of cobalt from spent Li-ion battery residues  

Microsoft Academic Search

Separation of the main metals contained in spent Li-ion batteries has been investigated using a treatment route consisting of the following steps: manual dismantling, acid leaching, precipitation with NH4OH and liquid–liquid extraction using Cyanex 272 [bis(2,4,4-trimethylpentyl) phosphinic acid] as the extractant agent. Aluminium, cobalt, lead and lithium were the main metal species identified in the residue. Lead was found solely

Germano Dorella; Marcelo Borges Mansur

2007-01-01

461

Synthesis and Characterization of Gold Clusters Ligated with 1,3-Bis(dicyclohexylphosphino)propane  

SciTech Connect

In this multidisciplinary study we combine chemical reduction synthesis of novel gold clusters in solution with high-resolution analytical mass spectrometry (MS) to gain insight into the composition of the gold clusters and how their size, ionic charge state and ligand substitution influences their gas-phase fragmentation pathways. Ultra small cationic gold clusters ligated with 1,3-bis(dicyclohexylphosphino)propane (DCPP) were synthesized for the first time and introduced into the gas phase using electrospray ionization (ESI). Mass-selected cluster ions were fragmented employing collision induced dissociation (CID) and the product ions were analysed using MS. The solutions were found to contain the multiply charged cationic gold clusters Au9L43+, Au13L53+, Au6L32+, Au8L32+ and Au10L42+ (L = DCPP). The gas-phase fragmentation pathways of these cluster ions were examined systematically employing CID combined with MS. In addition, CID experiments were performed on related gold clusters of the same size and ionic charge state but capped with 1,3-bis(diphenylphosphino)propane (DPPP) ligands containing phenyl functional groups at the two phosphine centers instead of cyclohexane rings. It is shown that this relatively small change in the molecular substitution of the two phosphine centers in diphosphine ligands (C6H11 versus C6H5) exerts a pronounced influence on the size of the species that are preferentially formed in solution during reduction synthesis as well as the gas-phase fragmentation channels of otherwise identical gold cluster ions. The mass spectrometry results indicate that in addition to the length of the alkyl chain between the two phosphine centers, the substituents at the phosphine centers also play a crucial role in determining the composition, size and stability of diphosphine ligated gold clusters synthesized in solution.

Johnson, Grant E.; Priest, Thomas A.; Laskin, Julia

2013-09-01

462

Dynamic tests for actinide/lanthanide separation by CMPO solvent in fluorinated diluents  

SciTech Connect

Actinide and lanthanide extraction by new solvent: 0.2 M phenyl-octyl-N,N-diiso-butylcarbamoyl-phosphine oxide (CMPO) + 30% TBP + formal of octafluoro-pentanol was studied. A dynamic test with this solvent was performed. It was shown that americium and lanthanides are effectively extracted from PUREX process raffinate. The separation of americium from light lanthanides was confirmed in the modified SETFICS flowsheet with this new solvent. (authors)

Tkachenko, L.; Babain, V.; Alyapyshev, M.; Vizniy, A.; Il'in, A. [V. G. Khlopin Radium Institute, 2nd Murinskiy Ave 28., St. Petersburg 194021 (Russian Federation); Shadrin, A. [A.A. Bochvar High-technology Research Institute of Inorganic Materials, 5-a, Rogova str., Moscow 123098 (Russian Federation)

2013-07-01

463

Iridium-catalyzed asymmetric hydrogenation of 2-pyridyl cyclic imines: a highly enantioselective approach to nicotine derivatives.  

PubMed

A highly efficient asymmetric hydrogenation of cyclic imines containing a pyridyl moiety was established by using iridium catalysts with chiral spiro phosphine-oxazoline ligands. This process will facilitate the development of new nicotine-related pharmaceuticals. The introduction of a substituent at the ortho position of the pyridyl ring to reduce its coordinating ability ensures the success of the hydrogenation and excellent enantioselectivity. PMID:25548865

Guo, Cui; Sun, Dong-Wei; Yang, Shuang; Mao, Shen-Jie; Xu, Xiao-Hua; Zhu, Shou-Fei; Zhou, Qi-Lin

2015-01-14

464

Vibrational analysis of pyramidal XY3-type molecules based on high-level ab initio potential energy surfaces: application to NH3  

Microsoft Academic Search

Variational calculations of the vibrational energies of the non-rigid and semirigid XY3 molecules, as ammonia and phosphine respectively, have been carried out [1,2]. In the procedure used is emphasized the umbrella motion due to the corresponding coordinate, for pyramidal non-rigid XY3 molecules, is the responsible of the torsional tunneling between different minima of the Potential Energy Surfaces. For the NH3

H. Lin; W. Thiel; S. N. Yurchenko; M. Carvajal; P. Jensen

2003-01-01

465

Low threshold 1.5 micron quantum well lasers grown by atmospheric pressure MOCVD with tertiarybutylarsine (TBA) and tertiarybutylphosphine (TBP)  

Microsoft Academic Search

TBA and TBP are liquid organometallic sources that are a safer alternative to arsine and phosphine. Using TBA and TBP, we have successfully grown lattice matched In(0.53)Ga(0.47)As\\/InP single quantum well lasers emitting at 1.5 micron with a threshold current density of 220A\\/sq cm for broad area devices 3.5 mm in length.

M. E. Heimbuch; A. L. Holmes Jr.; M. P. Mack; S. P. Denbaars; L. A. Coldren; J. E. Bowers

1993-01-01

466

CCMR: New Iridium Complexes for the Dehydrogenation of Alkanes  

NSDL National Science Digital Library

To introduce small variations on the previously investigated iridium P-C-P pincer complexes. The variations include substitution of cyclohexyl groups for the tert-butyl and the iso-propyl groups found on the phosphines.Thus, synthesis of these new iridium P-C-P pincer complexes was performed with the aim of improved catalytic dehydrogenation activity as well as a better understand of the influence that ligand sterics and electronics have on the active species.

Wang, David

2004-08-17

467

Review of HxPyOz-Catalyzed H + OH Recombination in Scramjet Nozzle Expansions; and Possible Phosphoric Acid Enhancement of Scramjet Flameholding, from Extinction of H3PO4 + H2—Air Counterflow Diffusion Flames  

Microsoft Academic Search

Recent detailed articles by Twarowski indicate that small quantities of phosphorus oxides and acids in the fuel-rich combustion products of H2 + phosphine (PH3) + air should significantly catalyze H, OH and O recombination kinetics during high-speed nozzle expansions -- to reform H2O, release heat, and approach equilibrium more rapidly and closely than uncatalyzed kinetics. This paper is an initial

Gerald L. Pellett

1996-01-01

468

Platinum Complexes of a Borane-Appended Analogue of 1,1'-Bis(diphenylphosphino)ferrocene: Flexible Borane Coordination Modes and in situ Vinylborane Formation.  

PubMed

Invited for the cover of this issue is the group of David Emslie at McMaster University (Canada). The image depicts the ferrocene-borane ligand as an industrial robot, with a conventional claw arm representing the bis-phosphine unit and an unconventional arm with a suction cup representing the borane acceptor. This single ligand gives access to multiple different bonding situations, hence the assembly line. Read the full text of the article at 10.1002/chem.201404846. PMID:25394179

Cowie, Bradley E; Emslie, David J H

2014-12-15

469

An update on toxicology of aluminum phosphide  

PubMed Central

Aluminum phosphide (AlP) is a cheap solid fumigant and a highly toxic pesticide which is commonly used for grain preservation. In Iran it is known as the “rice tablet”. AlP has currently aroused interest with increasing number of cases in the past four decades due to increased use in agricultural and non-agricultural purposesand also its easy availability in the markets has increased its misuse to commit suicide. Upon contact with moisture in the environment, AlP undergoes a chemical reaction yielding phosphine gas, which is the active pesticidal component. Phosphine inhibits cellular oxygen utilization and can induce lipid peroxidation. It was reported that AlP has a mortality rate more than 50% of intoxication cases. Poisoning with AlP has usually occurred in attempts to suicide. It is a more common case in adults rather than teen agers. In some eastern countries it is a very common agent with rapid action for suicide. Up to date, there is no effective antidote or treatment for its intoxication. Also, some experimental results suggest that magnesium sulfate, N-acetyl cysteine (NAC), glutathione, vitamin C and E, beta-carotenes, coconut oil and melatonin may play an important role in reducing the oxidative outcomes of phosphine. This article reviews the experimental and clinical features of AlP intoxication and tries to suggest a way to encounter its poisoning. PMID:23351193

2012-01-01

470

A systematic review of aluminium phosphide poisoning.  

PubMed

Every year, about 300,000 people die because of pesticide poisoning worldwide. The most common pesticide agents are organophosphates and phosphides, aluminium phosphide (AlP) in particular. AlP is known as a suicide poison that can easily be bought and has no effective antidote. Its toxicity results from the release of phosphine gas as the tablet gets into contact with moisture. Phosphine gas primarily affects the heart, lungs, gastrointestinal tract, and kidneys. Poisoning signs and symptoms include nausea, vomiting, restlessness, abdominal pain, palpitation, refractory shock, cardiac arrhythmias, pulmonary oedema, dyspnoea, cyanosis, and sensory alterations. Diagnosis is based on clinical suspicion, positive silver nitrate paper test to phosphine, and gastric aspirate and viscera biochemistry. Treatment includes early gastric lavage with potassium permanganate or a combination with coconut oil and sodium bicarbonate, administration of charcoal, and palliative care. Specific therapy includes intravenous magnesium sulphate and oral coconut oil. Moreover, acidosis can be treated with early intravenous administration of sodium bicarbonate, cardiogenic shock with fluid, vasopresor, and refractory cardiogenic shock with intra-aortic baloon pump or digoxin. Trimetazidine may also have a useful role in the treatment, because it can stop ventricular ectopic beats and bigeminy and preserve oxidative metabolism. This article reviews the epidemiological, toxicological, and clinical/pathological aspects of AlP poisoning and its management. PMID:22450207

Mehrpour, Omid; Jafarzadeh, Mostafa; Abdollahi, Mohammad

2012-03-01

471

An update on toxicology of aluminum phosphide.  

PubMed

Aluminum phosphide (AlP) is a cheap solid fumigant and a highly toxic pesticide which is commonly used for grain preservation. In Iran it is known as the "rice tablet". AlP has currently aroused interest with increasing number of cases in the past four decades due to increased use in agricultural and non-agricultural purposesand also its easy availability in the markets has increased its misuse to commit suicide. Upon contact with moisture in the environment, AlP undergoes a chemical reaction yielding phosphine gas, which is the active pesticidal component. Phosphine inhibits cellular oxygen utilization and can induce lipid peroxidation. It was reported that AlP has a mortality rate more than 50% of intoxication cases. Poisoning with AlP has usually occurred in attempts to suicide. It is a more common case in adults rather than teen agers. In some eastern countries it is a very common agent with rapid action for suicide. Up to date, there is no effective antidote or treatment for its intoxication. Also, some experimental results suggest that magnesium sulfate, N-acetyl cysteine (NAC), glutathione, vitamin C and E, beta-carotenes, coconut oil and melatonin may play an important role in reducing the oxidative outcomes of phosphine. This article reviews the experimental and clinical features of AlP intoxication and tries to suggest a way to encounter its poisoning. PMID:23351193

Moghadamnia, Ali Akbar

2012-01-01

472

Fatal aluminum phosphide poisoning.  

PubMed

A 39-year-old man committed suicide by ingestion of aluminum phosphide, a potent mole pesticide, which was available at the victim's workplace. The judicial authority ordered an autopsy, which ruled out any other cause of death. The victim was discovered 10 days after the ingestion of the pesticide. When aluminum phosphide comes into contact with humidity, it releases large quantities of hydrogen phosphine (PH3), a very toxic gas. Macroscopic examination during the autopsy revealed a very important asphyxia syndrome with major visceral congestion. Blood, urine, liver, kidney, adrenal, and heart samples were analyzed. Phosphine gas was absent in the blood and urine but present in the brain (94 mL/g), the liver (24 mL/g), and the kidneys (41 mL/g). High levels of phosphorus were found in the blood (76.3 mg/L) and liver (8.22 mg/g). Aluminum concentrations were very high in the blood (1.54 mg/L), brain (36 microg/g), and liver (75 microg/g) compared to the usual published values. Microscopic examination revealed congestion of all the organs studied and obvious asphyxia lesions in the pulmonary parenchyma. All these results confirmed a diagnosis of poisoning by aluminum phosphide. This report points out that this type of poisoning is rare and that hydrogen phosphine is very toxic. The phosphorus and aluminum concentrations observed and their distribution in the different viscera are discussed in relation to data in the literature. PMID:10732945

Anger, F; Paysant, F; Brousse, F; Le Normand, I; Develay, P; Gaillard, Y; Baert, A; Le Gueut, M A; Pepin, G; Anger, J P

2000-03-01

473

Late transition metal oxo and imido complexes. Progress report, May 15 1992--May 14, 1992  

SciTech Connect

A range of new phosphine Au(I) oxo complexes, [(LAu){sub 3}({mu}-O)]{sup +}, were prepared, testing the limits of the phosphine steric and electronic properties. Their reaction with reducing agents (hydrazines, CO and RNC) give a variety of new and known gold clusters in unprecedented high yields and establish the steric and electronic relationships between the phosphine and the nuclearity of the product Au cluster. The [L{sub 2}Pt({mu}-O)]{sub 2} class of dioxo complexes has been expanded to include the first anionic oxo complex, ([(dppm-H)Pt({mu}-O)]{sub 2})Li{sub 2} and the first Pt imido complexes, [(L{sub 2}Pt){sub 2}({mu}-O)({mu}-NR)] and [L{sub 2}Pt({mu}-NR)]{sub 2}. The previously observed Rh imido/amido A-frame chemistry has been extended to Ir. The p-MePh-imido complex has been characterized by X-ray diffraction and clearly shows the resonance delocalization of the nitrogen lone pair into the aryl ring which is responsible for the previously observed electrophilic ring addition and oxidative ring coupling reactions.

Sharp, P.R.

1992-12-01

474

Late transition metal oxo and imido complexes  

SciTech Connect

A range of new phosphine Au(I) oxo complexes, [(LAu)[sub 3]([mu]-O)][sup +], were prepared, testing the limits of the phosphine steric and electronic properties. Their reaction with reducing agents (hydrazines, CO and RNC) give a variety of new and known gold clusters in unprecedented high yields and establish the steric and electronic relationships between the phosphine and the nuclearity of the product Au cluster. The [L[sub 2]Pt([mu]-O)][sub 2] class of dioxo complexes has been expanded to include the first anionic oxo complex, ([(dppm-H)Pt([mu]-O)][sub 2])Li[sub 2] and the first Pt imido complexes, [(L[sub 2]Pt)[sub 2]([mu]-O)([mu]-NR)] and [L[sub 2]Pt([mu]-NR)][sub 2]. The previously observed Rh imido/amido A-frame chemistry has been extended to Ir. The p-MePh-imido complex has been characterized by X-ray diffraction and clearly shows the resonance delocalization of the nitrogen lone pair into the aryl ring which is responsible for the previously observed electrophilic ring addition and oxidative ring coupling reactions.

Sharp, P.R.

1992-12-01

475

Cassini/CIRS Observations of Saturn's "Storm Alley"  

NASA Technical Reports Server (NTRS)

In the Voyager era storms on Saturn were observed predominantly in the northern hemisphere, however, in recent years storm activity has been confined to a narrow range of latitudes referred to as "storm alley" (approx.40degS planetographic latitude). Throughout Cassini's prime mission storms have been detected by two independent instruments: ISS through dayside images and RPWS using radio emissions from Saturn Electrostatic Discharges (SED's) (Dyudina et al. 2007). Analysis of these storms indicates that the cloud tops are in the 200 - 500rnbar altitude range. During Saturn's Equinox, in August 2009, lSS imaged lightning on the night side in storm alley when ring-shine was at a minimum (Dyudina et al. 2010). This study indicates that lightning may have originated as deep as the water cloud. Decently, Cassini/CIRS was targeted at storm alley while a storm, originally detected by amateurs, was ongoing (March 2010). Phosphine can be used as a tracer of vertical transport because it is a disequilibrium species that falls off with altitude in the upper troposphere. CIRS can measure temperature and phosphine abundance independently in the altitude range where these cloud tops occur. Early analysis of these data shows stronger phosphine absorption at storm longitudes. This is an indication that powerful updrafts were dredging material upward into the upper troposphere. The results of the analysis of the March 2010 CIRS observations of storm alley will be presented.

Hesman, Brigette E.

2010-01-01

476

Effect of surface ligands on optical and electronic spectra of semiconductor nanoclusters.  

PubMed

We investigate the impact of ligands on the morphology, electronic structure, and optical response of the Cd(33)Se(33) cluster, which overlaps in size with the smallest synthesized CdSe nanocrystal quantum dots (QDs). Our density functional theory calculations demonstrate significant surface reorganization for both the bare cluster and the cluster capped with amine or phosphine oxide model ligands. We observe strong surface-ligand interactions leading to substantial charge redistribution and polarization effects on the surface. These effects result in the development of hybridized states, for which the electronic density is spread over the cluster and the ligands. The loss of one of the passivating ligands leads to either optically dark or bright additional states inside of the band gap, depending on the position of the leaving ligand on the QD surface. However, for fully ligated QDs, neither the ligand-localized nor hybridized molecular orbitals appear as trap states inside or near the band gap of the QD. Instead, being mostly optically dark, dense hybridized states could open new relaxation channels for high-energy photoexcitations. Comparing QDs passivated by different ligands, we also found that hybridized states are denser at the edge of the conduction band of the cluster ligated with phosphine oxide molecules than that with primary amines. Such a different manifestation of ligand binding may potentially lead to faster electron relaxation in QDs passivated by phosphine oxide than by amine ligands. PMID:19425603

Kilina, Svetlana; Ivanov, Sergei; Tretiak, Sergei

2009-06-10

477

Probing the reactivity of photoinitiators for free radical polymerization: time-resolved infrared spectroscopic study of benzoyl radicals.  

PubMed

A series of substituted benzoyl radicals has been generated by laser flash photolysis of alpha-hydroxy ketones, alpha-amino ketones, and acyl and bis(acyl)phosphine oxides, all of which are used commercially as photoinitiators in free radical polymerizations. The benzoyl radicals have been studied by fast time-resolved infrared spectroscopy. The absolute rate constants for their reaction with n-butylacrylate, thiophenol, bromotrichloromethane and oxygen were measured in acetonitrile solution. The rate constants of benzoyl radical addition to n-butylacrylate range from 1.3 x 10(5) to 5.5 x 10(5) M(-1) s(-1) and are about 2 orders of magnitude lower than for the n-butylacrylate addition to the counterradicals that are produced by alpha-cleavage of the investigated ketones. Density functional theoretical calculations have been performed in order to rationalize the observed reactivities of the initiating radicals. Calculations of the phosphorus-centered radicals generated by photolysis of an acyl and bis(acyl)phosphine oxide suggest that P atom Mulliken spin populations are an indicator of the relative reactivities of the phosphorus-centered radicals. The alpha-cleavage of (2,4,6-trimethylbenzoyl)phosphine oxide was studied by picosecond pump-probe and nanosecond step-scan time-resolved infrared spectroscopy. The results support a mechanism in which the alpha-cleavage occurs from the triplet excited state that has a lifetime less than or equal to the singlet excited state. PMID:12475337

Colley, Christopher S; Grills, David C; Besley, Nicholas A; Jockusch, Steffen; Matousek, Pavel; Parker, Anthony W; Towrie, Michael; Turro, Nicholas J; Gill, Peter M W; George, Michael W

2002-12-18

478

Reaction of a bridged frustrated Lewis pair with nitric oxide: a kinetics study.  

PubMed

Described is a kinetics and computational study of the reaction of NO with the intramolecular bridged P/B frustrated Lewis pair (FLP) endo-2-(dimesitylphosphino)-exo-3-bis(pentafluorophenyl)boryl-norbornane to give a persistent FLP-NO aminoxyl radical. This reaction follows a second-order rate law, first-order in [FLP] and first-order in [NO], and is markedly faster in toluene than in dichloromethane. By contrast, the NO oxidation of the phosphine base 2-(dimesitylphosphino)norbornene to the corresponding phosphine oxide follows a third-order rate law, first-order in [phosphine] and second-order in [NO]. Formation of the FLP-NO radical in toluene occurs with a ?H(‡) of 13 kcal mol(-1), a feature that conflicts with the computation-based conclusion that NO addition to a properly oriented B/P pair should be nearly barrierless. Since the calculations show the B/P pair in the most stable solution structure of this FLP to have an unfavorable orientation for concerted reaction, the observed barrier is rationalized in terms of the reversible formation of a [B]-NO complex intermediate followed by a slower isomerization-ring closure step to the cyclic aminoxyl radical. This combined kinetics/theoretical study for the first time provides insight into mechanistic details for the activation of a diatomic molecule by a prototypical FLP. PMID:24328325

Pereira, José Clayston Melo; Sajid, Muhammad; Kehr, Gerald; Wright, Ashley M; Schirmer, Birgitta; Qu, Zheng-Wang; Grimme, Stefan; Erker, Gerhard; Ford, Peter C

2014-01-01

479

Redox chemistry in the phosphorus biogeochemical cycle.  

PubMed

The element phosphorus (P) controls growth in many ecosystems as the limiting nutrient, where it is broadly considered to reside as pentavalent P in phosphate minerals and organic esters. Exceptions to pentavalent P include phosphine--PH3--a trace atmospheric gas, and phosphite and hypophosphite, P anions that have been detected recently in lightning strikes, eutrophic lakes, geothermal springs, and termite hindguts. Reduced oxidation state P compounds include the phosphonates, characterized by C-P bonds, which bear up to 25% of total organic dissolved phosphorus. Reduced P compounds have been considered to be rare; however, the microbial ability to use reduced P compounds as sole P sources is ubiquitous. Here we show that between 10% and 20% of dissolved P bears a redox state of less than +5 in water samples from central Florida, on average, with some samples bearing almost as much reduced P as phosphate. If the quantity of reduced P observed in the water samples from Florida studied here is broadly characteristic of similar environments on the global scale, it accounts well for the concentration of atmospheric phosphine and provides a rationale for the ubiquity of phosphite utilization genes in nature. Phosphine is generated at a quantity consistent with thermodynamic equilibrium established by the disproportionation reaction of reduced P species. Comprising 10-20% of the total dissolved P inventory in Florida environments, reduced P compounds could hence be a critical part of the phosphorus biogeochemical cycle, and in turn may impact global carbon cycling and methanogenesis. PMID:25313061

Pasek, Matthew A; Sampson, Jacqueline M; Atlas, Zachary

2014-10-28

480

Redox chemistry in the phosphorus biogeochemical cycle  

PubMed Central

The element phosphorus (P) controls growth in many ecosystems as the limiting nutrient, where it is broadly considered to reside as pentavalent P in phosphate minerals and organic esters. Exceptions to pentavalent P include phosphine—PH3—a trace atmospheric gas, and phosphite and hypophosphite, P anions that have been detected recently in lightning strikes, eutrophic lakes, geothermal springs, and termite hindguts. Reduced oxidation state P compounds include the phosphonates, characterized by C?P bonds, which bear up to 25% of total organic dissolved phosphorus. Reduced P compounds have been considered to be rare; however, the microbial ability to use reduced P compounds as sole P sources is ubiquitous. Here we show that between 10% and 20% of dissolved P bears a redox state of less than +5 in water samples from central Florida, on average, with some samples bearing almost as much reduced P as phosphate. If the quantity of reduced P observed in the water samples from Florida studied here is broadly characteristic of similar environments on the global scale, it accounts well for the concentration of atmospheric phosphine and provides a rationale for the ubiquity of phosphite utilization genes in nature. Phosphine is generated at a quantity consistent with thermodynamic equilibrium established by the disproportionation reaction of reduced P species. Comprising 10–20% of the total dissolved P inventory in Florida environments, reduced P compounds could hence be a critical part of the phosphorus biogeochemical cycle, and in turn may impact global carbon cycling and methanogenesis. PMID:25313061

Pasek, Matthew A.; Sampson, Jacqueline M.; Atlas, Zachary

2014-01-01

481

Oxorhenium complexes as aldehyde-olefination catalysts.  

PubMed

Several oxorhenium compounds in the formal oxidation states V and VII are examined as catalysts for the aldehyde-olefination starting from diazo compounds, phosphines, and aldehydes. Of these, [ReMeO2(eta2-alkyne)] complexes provide the simplest catalysts to study, although [ReOCl3(PPh3)2] still remains the most efficient rhenium catalyst for aldehyde-olefination described to date. Prior to the reaction with the Re catalysts the phosphine and the diazo compound react to form a phosphazine. No catalytic reaction occurs in cases where no phosphazine formation is observed. The first step of the catalytic cycle involves the formation of a carbene intermediate by the reaction of phosphazine and catalyst under extrusion of phosphine oxide and dinitrogen. In a second step the carbene reacts with aldehyde under olefin formation and catalyst regeneration. Excess of alkyne as well as the presence of ketones slows down the catalytic reaction. The olefination of 4-nitrobenzaldehyde with diazomalonate is possible with these Re catalysts. In contrast, this reaction does not take place either in the classical Wittig fashion from Ph3P=C(CO2Et)2 and aldehyde or by use of all other catalysts for aldehyde olefination reactions reported to date. Catalytic ylide formation from diazo compounds seems therefore not to be the only pathway through which catalytic aldehyde-olefination reactions can proceed. PMID:15526317

Santos, Ana M; Pedro, Filipe M; Yogalekar, Ameya A; Lucas, Isabel S; Romão, Carlos C; Kühn, Fritz E

2004-12-01

482

Ruthenium Hydrides Containing the Superhindered Polydentate Polyphosphine Ligand P(CH2CH2P(t)Bu2)3.  

PubMed

The complex RuH2(N2)(P(2)P3(tBu)) (1) containing the extremely bulky PP3-type ligand P(2)P3(tBu) = P(CH2CH2P(t)Bu2)3 was synthesized by reduction of RuCl2(P(2)P3(tBu)) (2) with Na/NH3 under a N2 atmosphere. Like other complexes containing the P(2)P3(tBu) ligand, only three of the four donor phosphines are coordinated, and one of the phosphines remains as a dangling pendant phosphine. Reduction of RuCl2(P(2)P3(tBu)) (2) with a range of the more usual hydride reducing agents afforded the previously unknown ruthenium hydride complexes RuHCl(P(2)P3(tBu)) (3), RuH(BH4)(P(2)P3(tBu)) (6), RuH(AlH4)(P(2)P3(tBu)) (7), and the ruthenium(II) trihydride K[Ru(H)3(P(2)P3(tBu))] (8). The ruthenium tetrahydride containing a coordinated H2 ligand RuH2(H2)(P(2)P3(tBu)) (10) was synthesized by exchange of N2 in 1 by H2. Complexes 1, 3, 6, 7, and 8 were characterized by crystallography and multinuclear NMR spectroscopy. PMID:25390508

Gilbert-Wilson, Ryan; Field, Leslie D; Bhadbhade, Mohan

2014-12-01

483

Chemical Methods for the Direct Detection and Labeling of S-Nitrosothiols  

PubMed Central

Abstract Significance: Posttranslational modification of proteins through phosphorylation, glycosylation, and oxidation adds complexity to the proteome by reversibly altering the structure and function of target proteins in a highly controlled fashion. Recent Advances: The study of reversible cysteine oxidation highlights a role for this oxidative modification in complex signal transduction pathways. Nitric oxide (NO), and its respective metabolites (including reactive nitrogen species), participates in a variety of these cellular redox processes, including the reversible oxidation of cysteine to S-nitrosothiols (RSNOs). RSNOs act as endogenous transporters of NO, but also possess beneficial effects independent of NO-related signaling, which suggests a complex and versatile biological role. In this review, we highlight the importance of RSNOs as a required posttranslational modification and summarize the current methods available for detecting S-nitrosation. Critical Issues: Given the limitations of these indirect detection methods, the review covers recent developments toward the direct detection of RSNOs by phosphine-based chemical probes. The intrinsic properties that dictate this phosphine/RSNO reactivity are summarized. In general, RSNOs (both small molecule and protein) react with phosphines to yield reactive S-substituted aza-ylides that undergo further reactions leading to stable RSNO-based adducts. Future Directions: This newly explored chemical reactivity forms the basis of a number of exciting potential chemical methods for protein RSNO detection in biological systems. Antioxid. Redox Signal. 17, 981–991. PMID:22356122

Bechtold, Erika

2012-01-01

484

Coinage metal complexes supported by the tri- and tetraphosphine ligands.  

PubMed

A series of tri- and tetranuclear phosphine complexes of d(10) metal ions supported by the polydentate ligands, bis(diphenylphosphinomethyl)phenylphosphine (PPP) and tris(diphenylphosphinomethyl)phosphine (PPPP), were synthesized. All the compounds under study, [AuM2(PPP)2](3+) (M = Au (1), Cu (2), Ag (3)), [M4(PPPP)2](4+) (M = Ag (4), Au (5)), [AuAg3(PPPP)2](4+) (6), and [Au2Cu2(PPPP)2(NCMe)4](4+) (7), were characterized crystallographically. The trinuclear clusters 1-3 contain a linear metal core, while in the isostructural tetranuclear complexes 4-6 the metal framework has a plane star-shaped arrangement. Cluster 7 adopts a structural motif that involves a digold unit bridged by two arms of the PPPP phosphines and decorated two spatially separated Cu(I) ions chelated by the remaining P donors. The NMR spectroscopic investigation in DMSO solution revealed the heterometallic clusters 2, 3, and 6 are stereochemically nonrigid and undergo reversible metal ions redistribution between several species, accompanied by their solvation-desolvation. The complexes 1-3 and 5-7 exhibit room temperature luminescence in the solid state (?em = 6-64%) in the spectral region from 450 to 563 nm. The phosphorescence observed originates from the triplet excited states, determined by the metal cluster-centered d?* ? p? transitions. PMID:24750114

Dau, Minh Thuy; Shakirova, Julia R; Karttunen, Antti J; Grachova, Elena V; Tunik, Sergey P; Melnikov, Alexey S; Pakkanen, Tapani A; Koshevoy, Igor O

2014-05-01

485

The role of ligands in the optical and electronic spectra of CdSe nanoclusters  

SciTech Connect

We investigate the impact of ligands on morphology, electronic structure, and optical response of the Cd33Se33 cluster, which already overlapps in size with the smallest synthesized CdSe quantum dots (QDs). Our Density Functional Theory (DFT) calculations demonstrate significant surface reorganization both for the bare cluster and for the cluster capped by amine and phosphine oxide ligand models. We observe strong surface-ligand interactions leading to substantial charge redistribution and polarization effects on the surface. This effect results in the appearance of hybridized states, where the electronic density is spread over the cluster and the ligands. Neither the ligand's nor hybridized molecular orbitals appear as trap states inside or near the band gap of the QD. Instead, being optically dark, dense hybridized states from the edges of the valence and the conduction bands could open new relaxation channels for high energy photoexcitations. Comparing quantum dots passivated by different ligands, we found that hybridized states are denser in at the edge of the conduction band of the cluster ligated with phosphine oxide molecules than that with primary amines. Such a different manifestation of ligand binding may potentially lead to the faster electron relaxation in dots passivated by phosphine oxide than by amine ligands, which is in agreement with experimental data.

Kilina, Svletana [Los Alamos National Laboratory; Sergei, Ivanov A [Los Alamos National Laboratory; Victor, Klimov I [Los Alamos National Laboratory; Sergei, Tretiak [Los Alamos National Laboratory

2008-01-01

486

Combined homogeneous and heterogeneous catalysts  

Microsoft Academic Search

The rhodium carbonyl thiolate complex, Rh2[?-S(CH2)3Si(OCH3)3]2(CO)4 (Rh–S) was tethered to phosphine-modified Pd–SiO2 (P–(Pd–SiO2)), which was prepared by tethering the phosphine ligand Ph2P(CH2)3Si(OC2H5)3 to Pd–SiO2, to give the tethered complex catalyst Rh–S\\/P–(Pd–SiO2). Also, the phosphine-substituted Rh2[?-S(CH2)3Si(OCH3)3]2[Ph2P(CH2)3Si(OC2H5)3]2(CO)2 (Rh–S–P) was tethered to several silica-supported metal heterogeneous catalysts M–SiO2 (M=Pd, Pt, Ru, Ir) to give Rh–S–P\\/M–SiO2. These complex catalysts, consisting of a tethered complex

Hanrong Gao; Robert J Angelici

1999-01-01

487

Synthesis, characterization and catalytic activity of saturated and unsaturated N-heterocyclic carbene iridium(i) complexes.  

PubMed

Both saturated and unsaturated N-benzyl substituted heterocyclic carbene (NHC) iridum(i) complexes were synthesized. The unsaturated carbene complex [(un-NHC-Bn)Ir(CO)(2)Cl] in the cis form was prepared via the carbene transfer from the corresponding silver complex to [Ir(COD)(2)Cl](2) followed by ligand substitution with CO, whereas the saturated complex was obtained via the transfer from (sat-NHC-Bn)W(CO)(5). The treatment of phosphines with (NHC)Ir(CO)(2)Cl complexes yielded the products with the phosphine ligand trans to the carbene moiety via substitution. X-Ray structural determination shows that distances of Ir-C((carbene)) in both (un-NHC-Bn)Ir(CO)(PR(3))Cl and (un-NHC-Bn)Ir(CO)(PR(3))Cl are essentially the same. Analyses of spectroscopic and crystal structural data of iridium complexes [(NHC)Ir(CO)(PR(3))Cl] and Vaska's complex show similar corresponding data in both types of complexes, suggesting that the studied NHC ligands and phosphines have similar bonding with Ir(i) metal center. All iridium complexes studied in this work illustrated their catalytically activity on N-alkylation of amine with alcohol via hydrogen transfer reduction. It appears no dramatic difference on the catalytic activity among these iridium carbene complexes; but the saturated carbene complex (sat-NHC-Bn)Ir(CO)(PR(3))Cl appears to be slightly more active. For example, the