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1

Microbially mediated phosphine emission.  

PubMed

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

Roels, Joris; Huyghe, Gwen; Verstraete, Willy

2005-02-15

2

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

3

Molecular Structure of Phosphine  

NSDL National Science Digital Library

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

2003-06-04

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

Efficient Synthesis of (P-Chirogenic) o-Boronated Phosphines from sec-Phosphine Boranes.  

PubMed

An efficient synthesis of boronated phosphines with an o-phenylene-bridge prepared from sec-phosphine boranes and using benzyne chemistry is reported. Successive reactions of sec-phosphine boranes with n-BuLi and 1,2-dibromobenzene, and then with boron reagents, afford the o-boronatophenylphosphine derivatives in 71% yields. The use of P-chirogenic sec-phosphine boranes leads to the free boronated phosphines with retention of configuration at the P-center after decomplexation. The reaction of P-chirogenic o-boronatophenylphosphine with KHF2 affords the corresponding trifluoroborated phosphine with ee >98%. PMID:25680028

Bayardon, Jérôme; Bernard, Julie; Rémond, Emmanuelle; Rousselin, Yoann; Malacea-Kabbara, Raluca; Jugé, Sylvain

2015-03-01

7

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

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

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

11

CYTOGENETIC EFFECTS OF PHOSPHINE INHALATION BY RODENTS  

EPA Science Inventory

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

12

Occurrence and origin of phosphine in landfill gas.  

PubMed

A landfill (Hooge Maey, Flanders, Belgium) was subjected to an in-depth study in order to explain the origin of phosphine detected in high amounts in landfill gas, in comparison with biogas from other sources, during a previous study. The spatial and temporal variability of the phosphine concentration in landfill gas was assessed. Twenty-four wells were monitored and differences in phosphine concentration up to one log unit were observed (3.2-32.4 microg/m(3)). The phosphine concentration in each well was constant in time over a period of 4 months. No correlation was found between the phosphine concentration and methane, carbon dioxide, hydrogen sulfide, ethene or ethane concentration. In a series of laboratory tests, it was shown that phosphine was emitted during batch fermentation tests inoculated with landfill leachate when Fe(0) or Al(0) specimens were added. Conditions favouring corrosion of iron gave rise to higher emissions of phosphine. The phosphine concentration in the headspace of a batch test rose to 1.43 mg/m(3) after 27 days of incubation. Weight loss of corroding steel coupons correlated with phosphine emission. Calculations showed that all phosphine emitted from the 0.005 km(3) landfill (160 g/year) could be attributed to corrosion of metals. No evidence of de novo synthesis could be established. PMID:15172581

Roels, Joris; Verstraete, Willy

2004-07-01

13

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

14

Prototypical phosphine complexes of antimony(III).  

PubMed

Complexes of the generic formula [Cln(PR3)mSb]((3-n)+) (n = 1, 2, 3, or 4 and m = 1 or 2) have been prepared featuring [ClSb](2+), [Cl2Sb](1+), Cl3Sb, or [Cl4Sb](1-) as acceptors with one or two phosphine ligands {PMe3, PPh3, PCy3 (Cy = C6H11)}. The solid-state structures of the complexes reveal foundational features that define the coordination chemistry of a lone pair bearing stibine acceptor site. The experimental observations are interpreted with dispersion-corrected density functional theory calculations to develop an understanding of the bonding and structural diversity. PMID:24773563

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

2014-05-19

15

Sublethal exposure to phosphine decreases offspring production in strongly phosphine resistant female red flour beetles, Tribolium castaneum (Herbst).  

PubMed

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

16

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

17

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

18

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

19

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

20

Phosphine resistance in Brazilian populations of Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae)  

Microsoft Academic Search

Phosphine resistance was assessed in adults of 22 Brazilian populations of Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae). The concentration–mortality bioassays for the detection of phosphine resistance followed the FAO standard method. Twenty populations of S. zeamais were resistant to phosphine and the resistance ratios at the LC50 ranged from 1.1- to 86.6-fold. This is the first report of phosphine resistance in

M. A. G. Pimentel; L. R. D'A. Faroni; R. N. C. Guedes; A. H. Sousa; M. R. Tótola

2009-01-01

21

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

PubMed

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

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

2013-01-01

22

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

23

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

Code of Federal Regulations, 2014 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...

2014-07-01

24

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

25

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

26

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

27

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

PubMed Central

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

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

2013-01-01

28

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

29

Mechanism of phosphine borane deprotection with amines: the effects of phosphine, solvent and amine on rate and efficiency.  

PubMed

The kinetics of borane transfer from simple tertiary phosphine borane adducts to a wide range of amines have been determined. All data obtained, including second-order kinetics, lack of cross-over, and negative entropies of activation for reaction of triphenylphosphine borane with quinuclidine and triethylamine, are consistent with a direct (SN 2-like) transfer process, rather than a dissociative (SN 1-like) process. The identities of the amine, phosphine, and solvent all impact substantially on the rate (k) and equilibrium (K) of the transfer, which in some cases vary by many orders of magnitude. P-to-N transfer is more efficient with cyclic amines in apolar solvents due to reduced entropic costs and ground-state destabilisation. Taken as a whole, the data allow informed optimisation of the deprotection step from the stand-point of rate, or synthetic convenience. In all cases, both reactants should be present at high initial concentration to gain kinetic benefit from the bimolecularity of the process. Ultimately, the choice of amine is dictated by the identity of the phosphine borane complex. Aryl-rich phosphine boranes are sufficiently reactive to allow use of diethylamine or pyrrolidine as a volatile low polarity solvent and reactant, whereas more alkyl-rich phosphines benefit from the use of more reactive amines, such as 1,4-diaza[2.2.2]bicyclooctane (DABCO), in apolar solvents at higher temperatures. PMID:25704230

Lloyd-Jones, Guy C; Taylor, Nicholas P

2015-03-27

30

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

E-print Network

persistent leaching occurs. Al2O3 was applied in the basic, neutral, and acidic versions. All of them needed extensive washing, and leaching of the phosphine was found for acidic Al2O3. With alumina and silica to leaching and convenience of handling, SiO2 turned out to be the most favorable support for immobilizing

Bluemel, Janet

31

Laser-Initiated Reaction Of Phosphine And Nitrogen Fluorides  

NASA Astrophysics Data System (ADS)

The reaction of phosphine and nitrogen trifluoride initiated by a CW CO2 laser has produced several interesting results. Mixtures that are rich in phosphine produced a brownish polymeric film, along with phosphorus trifluoride, hydrogen fluoride, and nitrogen. The infrared spectra of the polymer indicated that N-H, P=N, and P-F vibrational bands were present. It was observed that when hydrogen bonded NH vibrational bands were present in the IR, the polymeric film was slightly conductive. The film could also be made to be conductive by doping with iodine vapors. The polymer film was observed to decompose slowly when exposed to air due to hydrolysis. A visible emission is observed when the phosphine and nitrogen trifluoride mixtures are irradiated. Spectral analysis of this fluorescence showed that the discrete spectra was due to PF, CN, atomic Na, and CaF. Most of the fluorescence was the result of a continuum that extended across the visible into the near infrared. The emission was observed to give simple exponential decay to oscillations with spikes as the nitrogen trifluoride to phosphine ratio was increased. The oscillations have been shown to be due to the shock waves generated by the reaction traversing the cell. The reaction cell was fitted with Brewster angle windows and placed in a hole-coupled cavity to determine if lasing could be obtained. Some gain has been observed from 400 to 800 nm. A comparison of the laser-induced emission to the emission from the phosphine/nitrogen trifluoride flame has also been made.

McDonald, Joseph K.; Jones, Roger W.

1986-11-01

32

Oxygen plasma resistant phosphine oxide containing imide/arylene copolymers  

NASA Technical Reports Server (NTRS)

A series of oxygen plasma resistant imide/arylene ether copolymers were prepared by reacting anhydride-terminated poly(amide acids) and amine-terminated polyarylene ethers containing phosphine oxide units. Inherent viscosities for these copolymers ranged from 0.42 to 0.80 dL/g. After curing, the resulting copolymers had glass transition temperatures ranging from 224 C to 228 C. Solution cast films of the block copolymers were tough and flexible with tensile strength, tensile moduli, and elongation at break up to 16.1 ksi, 439 ksi, and 23 percent, respectively at 25 C and 9.1 ksi, 308 ksi and 97 percent, respectively at 150 C. The copolymers show a significant improvement in resistance to oxygen plasma when compared to the commercial polyimide Kapton. The imide/arylene ether copolymers containing phosphine oxide units are suitable as coatings, films, adhesives, and composite matrices.

Jensen, Brian J.

1993-01-01

33

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

34

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

35

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

PubMed

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

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

2008-04-01

36

Biaryl Phosphine Ligands in Palladium-Catalyzed Amination  

PubMed Central

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

Surry, David S.

2012-01-01

37

Structure—property behaviour of gamma irradiated phosphinic acid resins  

Microsoft Academic Search

The effect of high dose (1000–6000 kGy) gamma radiation on the chemical and physical properties of the ionic polymer phosphinic acid resin has been investigated. It was found that the resin irradiated to a dose of 1000 kGy shows a decrease in the acid capacity of about 8%, reaching 25% at 6000 kGy. In addition, the grain size of the

A. M. El-Naggar; A. S. Emara; S. G. Abd Alla

1997-01-01

38

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

PubMed

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

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

2011-09-28

39

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

40

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

41

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...

42

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

PubMed

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

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

2013-08-01

43

Phosphine-free palladium acetate catalyzed Suzuki reaction in water.  

PubMed

Pd(OAc)(2) in a mixture of water and poly(ethylene glycol) (PEG) is shown to be an extremely active catalyst for the Suzuki reaction of aryl iodides and bromides. The reaction can be conducted under mild conditions (50 degrees C) without the use of a microwave or phosphine ligand in high yields. The isolation of the products is readily performed by the extraction of diethyl ether, and the Pd(OAc)(2)-PEG can be reused without significant loss in activity. PMID:16018716

Liu, Leifang; Zhang, Yuhong; Wang, Yanguang

2005-07-22

44

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

45

Polyimides Containing Pendent Phosphine Oxide Groups for Space Applications  

NASA Technical Reports Server (NTRS)

As part of an ongoing materials development activity to produce high performance polymers that are durable to the space environment, phosphine oxide containing polyimides have been under investigation. A novel dianhydride was prepared from 2,5-dihydroxyphenyldiphenylphosphine oxide in good yield. The dianhydride was reacted with commercially available diamines, and a previously reported diamine was reacted with commercially available dianhydrides to prepare isomeric polyimides. The physical and mechanical properties, particularly thermal and optical properties, of the polymers were determined. One material exhibited a high glass transition temperature, high tensile properties, and low solar absorptivity. The chemistry, physical, and mechanical properties of these resins will be discussed.

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

2002-01-01

46

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

47

Do phosphine resistance genes influence movement and dispersal under starvation?  

PubMed

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

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

2013-10-01

48

Toxicity of phosphine to Carposina niponensis (Lepidoptera: Carposinadae) at low temperature.  

PubMed

Carposina niponensis Matsumura (Lepidoptera: Carposinadae), is widely distributed in pome fruit production areas in China and presents a problem in some export markets because it is considered a quarantine pest by some countries. Methyl bromide is the only fumigant used for fumigation of apples (Malus spp.) for export. However, phosphine is a candidate replacement that can be applied directly at low temperature. Here, laboratory tests showed that tolerance of different stages of C. niponensis to phosphine fumigation at 0 degrees C differed greatly; first-second-instar larvae were the least tolerant stage and the mature fifth instars were the most tolerant stage. In the mature larvae, fumigation tests, with a range of phosphine concentrations from 0.42 to 1.95 mg/liters and exposure periods of 24 h to 14 d at 0 degrees C indicated narcosis when phosphine concentration was > or = 1.67 mg/liter and that a 15.52-8.14-d fumigation period was required to achieve 99% mortality with different phosphine concentrations. The expression of C(0.7)T = k was obtained, which indicated that exposure time was much more important than concentration of phosphine in mortality of mature larvae of C. niponensis. All results suggested that phosphine fumigation at low temperature offers promising control of C. niponensis infestation in pome fruit. PMID:21309217

Bo, Liu; Fanhua, Zhang; Yuejin, Wang

2010-12-01

49

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

PubMed

Light brown apple moth, Epiphyas postvittana (Walker), is a quarantined pest in most countries. Its establishment in California and potential spread to other parts of the state and beyond make it urgent to develop effective postharvest treatments to control the pest on fresh commodities. Fumigation with cylindered phosphine at low temperature has emerged to be a practical methyl bromide alternative treatment for postharvest pest control on fresh commodities. However, its use to control E. postvittana eggs on sensitive commodities such as lettuce is problematic. E. postvittana eggs are tolerant of phosphine and long phosphine treatment also injures lettuce. In the current study, E. postvittana eggs were subjected to oxygenated phosphine fumigations to develop an effective treatment at a low storage temperature of 2 degrees C. In addition, soda lime as a CO2 absorbent was tested to determine its effects in reducing and preventing injuries to lettuce associated with phosphine fumigations. Three-day fumigation with 1,000 ppm phosphine under 60% O2 achieved 100% mortality of E. postvittana eggs in small-scale laboratory tests. In the presence of the CO2 absorbent, a 3-d large-scale fumigation of lettuce with 1,700 ppm phosphine under 60% O2 resulted in a relative egg mortality of 99.96% without any negative effect on lettuce quality. The 3-d fumigation treatment without the CO2 absorbent, however, resulted in significant injuries to lettuce and consequential quality reductions. The study demonstrated that oxygenated phosphine fumigation has the potential to control E. postvittana eggs and the CO2 absorbent has the potential to prevent injuries and quality reductions of lettuce associated with long-term oxygenated phosphine fumigation. PMID:25195424

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

2014-08-01

50

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

PubMed Central

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

Queffelec, Clémence; Ribière, Patrice; Montchamp, Jean-Luc

2009-01-01

51

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

E-print Network

and in HRMAS NMR spectra the reduction of the originally large CSA, the residual halfwidth, as well as the downfield shift of the signals when adsorbing phosphine oxides on silica surfaces are most indicative. This research provides new insights regarding...

Hilliard, Casie Renee

2013-12-09

52

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

Technology Transfer Automated Retrieval System (TEKTRAN)

Light brown apple moth (LBAM), Epiphyas postvittana (Walker), eggs were subjected to regular and oxygenated phosphine fumigations at different temperatures to compare their susceptibilities to the two different fumigation methods and determine effective treatments in laboratory tests. LBAM eggs wer...

53

Highly enantioselective hydroformylation of dihydrofurans catalyzed by hybrid phosphine-phosphonite rhodium complexes.  

PubMed

Unprecedented regio- and enantioselectivities (>91%) are reported for the Rh-catalyzed asymmetric hydroformylation of 2,3- and 2,5-dihydrofuran using tunable hybrid phosphine-phosphonite ligands. PMID:20449264

Chikkali, Samir H; Bellini, Rosalba; Berthon-Gelloz, Guillaume; van der Vlugt, Jarl Ivar; de Bruin, Bas; Reek, Joost N H

2010-02-28

54

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

55

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

56

Dynamic control of chirality in phosphine ligands for enantioselective catalysis  

PubMed Central

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

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

2015-01-01

57

Structures and unexpected dynamic properties of phosphine oxides adsorbed on silica surfaces.  

PubMed

Solid-state NMR spectroscopy of selected phosphine oxides adsorbed on silica surfaces establishes the surface mobilities, even of phosphine oxides with high melting points. Crystal structures of the adducts Ph3 PO?HOSiPh3 and Cy3 PO?H2 O indicate that the interactions with silica involve hydrogen bonding of the P=O group to adsorbed water and surface silanol groups. PMID:25394806

Hilliard, Casie R; Kharel, Sugam; Cluff, Kyle J; Bhuvanesh, Nattamai; Gladysz, John A; Blümel, Janet

2014-12-22

58

Evidence for phosphine production and emission from Louisiana and Florida marsh soils  

Microsoft Academic Search

A diffusion chamber and solid adsorbent preconcentration technique followed by thermal desorption and gas chromatography were developed for quantifying phosphine production and emission from wetland soils. The first quantifiable emissions of phosphine from wetlands to the atmosphere are reported measured in Louisiana brackish (0.42-3.03 ng pH3\\/m2\\/h) and salt (0.91-6.52 ng PH3\\/m2\\/h) marshes. Laboratory experiments have demonstrated that Florida Everglades marsh

Istvan Devai; R. D. Delaune

1995-01-01

59

Polyimide–silver nanocomposite containing phosphine oxide moieties in the main chain: Synthesis and properties  

Microsoft Academic Search

New flame-retardant polyimide–silver nanocomposite containing phosphine oxide moiety in the main chain was synthesized by a convenient ultraviolet irradiation technique. A precursor such as AgNO3 was used as the source of the silver particles. Polyimide 6 as a source of polymer was synthesized by polycondensation reaction of bis (3-aminophenyl) phenyl phosphine oxide 4 with pyromellitic anhydride 5 in the presence

Khalil Faghihi; Mohsen Hajibeygi; Meisam Shabanian

2010-01-01

60

Phosphine resistance, respiration rate and fitness consequences in stored-product insects.  

PubMed

Resistance to fumigants has been frequently reported in insect pests of stored products and is one of the obstacles in controlling these pests. The authors studied phosphine resistance and its physiological basis in adult insects of 12 populations of Tribolium castaneum (Herbst) (Tenebrionidae), ten populations of Rhyzopertha dominica (F.) (Bostrichidae) and eight populations of Oryzaephilus surinamensis L. (Silvanidae) from Brazil, and the possible existence of fitness costs associated with phosphine resistance in the absence of this fumigant. The bioassays for the detection of phosphine resistance followed the FAO standard method. The production of carbon dioxide and the instantaneous rate of population increase (r(i)) of each population of each species were correlated with their resistance ratios at the LC(50). The resistance ratio at LC(50) in T. castaneum ranged from 1.0- to 186.2-fold, in R. dominica from 2.0- to 71.0-fold and in O. surinamensis from 1.9- to 32.2-fold. Ten populations of T. castaneum, nine populations of R. dominica and seven populations of O. surinamensis were resistant to phosphine. In all three species there was significant association (P < 0.05) between respiration rate and phosphine resistance. The populations with lower carbon dioxide production showed a higher resistance ratio, suggesting that the lower respiration rate is the physiological basis of phosphine resistance by reducing the fumigant uptake in the resistant insects. Conversely, populations with higher r(i) showed lower resistance ratios, which could indicate a lower rate of reproduction of the resistant populations compared with susceptible populations. Thus, management strategies based on the interruption of phosphine fumigation may result in reestablishment of susceptibility, and shows good potential for more effective management of phosphine-resistant populations. PMID:17597470

Pimentel, Marco Aurélio G; Faroni, Lêda Rita D'A; Tótola, Marcos R; Guedes, Raul Narciso C

2007-09-01

61

Gas phase ion/molecule reactions in phosphine/germane mixtures studied by ion trapping  

NASA Astrophysics Data System (ADS)

Gaseous mixtures of phosphine and germane have been investigated by ion trap mass spectrometry. Reaction pathways together with rate constants of the main reactions are reported. The mechanisms of ion/molecule reactions have been elucidated by single and multiple isolation steps. The GeHn+ (n = 1-3) ions react with phosphine to give GePHn+ (n = 2-4) ions. The GePH4+ ion further reacts with GeH4 to yield Ge2PH6+. The GePHn+ (n = 2-4) mixed ionic family also originates from the P+ phosphine primary ion, as well as from the P2Hn+ (n = 0-3) secondary ions of phosphine reacting with neutral germane and from Ge2H2+ reacting with phosphine. The main reaction pathways of the PHn+ (n = 0-2) ions with GeH4 lead to the formation of the GeH2+ and GeH3+ ionic species. Protonation of phosphine from different ionic precursors is a very common process and yields the stable phosphonium ion, PH4+. Trends in total abundances of secondary GePHn+ (n = 2-4) ions as function of reaction time for different PH3/GeH4 pressure ratios show that excess of germane slightly affects the nucleation of mixed Ge-P ions.

Benzi, P.; Operti, L.; Rabezzana, R.; Splendore, M.; Volpe, P.

1996-01-01

62

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

63

Phosphine-initiated cation exchange for precisely tailoring composition and properties of semiconductor nanostructures: old concept, new applications.  

PubMed

Phosphine-initiated cation exchange is a well-known inorganic chemistry reaction. In this work, different phosphines have been used to modulate the thermodynamic and kinetic parameters of the cation exchange reaction to synthesize complex semiconductor nanostructures. Besides preserving the original shape and size, phosphine-initiated cation exchange reactions show potential to precisely tune the crystallinity and composition of metal/semiconductor core-shell and doped nanocrystals. Furthermore, systematic studies on different phosphines and on the elementary reaction mechanisms have been performed. PMID:25655404

Gui, Jing; Ji, Muwei; Liu, Jiajia; Xu, Meng; Zhang, Jiatao; Zhu, Hesun

2015-03-16

64

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

PubMed Central

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

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

2014-01-01

65

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

66

Diazaphospholenes: N-heterocyclic phosphines between molecules and Lewis pairs.  

PubMed

The interest in geometrically distorted or electronically polarized molecules is often motivated by the realization that unusual structures can engender unprecedented physical or chemical properties. 1,3,2-Diazaphospholenes are N-heterocyclic phosphines (NHPs) that have ring structures similar to N-heterocyclic carbenes (NHCs). Although NHPs were initially mainly of interest as precursors for carbene-analogous phosphenium cations, it was noted that they exhibit quite peculiar structural features and remarkable chemical behavior on their own. In this Account, we discuss both structure and chemistry in connection with the special bonding situation that is characterized by significant n(N)-?*(P-X) hyperconjugation and induces a strong ionic polarization of the P-X bonds. This induced polarization is surprisingly maintained even when P and X have similar or like electronegativities (for example, X = H, P) and offers the possibility to design compounds with polarized homonuclear bonds. An exemption from the general pattern was only noted for some P-amino-NHPs in which reverse hyperconjugation weakens endocyclic P-N bonds and was predicted to facilitate ring fragmentation and formation of phosphinidenes. An important corollary of the P-X bond polarization in NHPs is a unique bond lengthening, which not only can be fine-tuned by adjusting intramolecular steric and electronic interactions but also responds to intermolecular influences and solvent effects. Insight from crystallographic, spectroscopic, and computational studies allows the development of concepts for controlled manipulation of the bonding, up to a point where P-X bonds are dominated by electrostatic interactions and species behave as Lewis pairs rather than covalent molecules. An appealing aspect lies in the fact that this P-X bond polarization induces reactivities that have hardly any precedence in phosphine chemistry. Examples include (i) reactions of P-hydrogen-substituted NHPs as hydride transfer reagents, (ii) metatheses and additions to multiple bonds (diphosphination) of phosphino-NHPs, which can be used to catalyze P-C cross-coupling reactions and to synthesize 1,2-bisphosphine ligands, (iii) cyclopentadienyl (Cp) transfer reactions of P-Cp-NHPs, and (iv) metal insertion into the P-X bonds of P-halogeno-NHPs. In many aspects, these reactions have potentially useful mechanistic or synthetic implications, and their future exploitation might help to convert NHPs from academically interesting species into useful reagents. PMID:20572668

Gudat, Dietrich

2010-10-19

67

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

PubMed

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

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

2010-01-01

68

Biomolecule conjugation strategy using novel water-soluble phosphine-based chelating agents  

DOEpatents

This invention describes a novel strategy to produce phosphine-functionalized biomolecules (e.g. peptides or proteins) for potential use in the design and development of site-specific radiopharmaceuticals for diagnosis or therapy of specific cancers. Hydrophilic alkyl phosphines, in general, tend to be oxidatively unstable. Therefore, incorporation of such phosphine functionalities on peptide (and other biomolecule) backbones, without oxidizing the P.sup.III centers, is difficult. In this context this discovery reports on a new technology by which phosphines, in the form of bifunctional chelating agents, can be directly incorporated on biomolecular backbones using manual synthetic or solid phase peptide synthesis methodologies. The superior ligating abilities of phosphine ligands, with various diagnostically (e.g. TC-99m) or therapeutically (e.g. Re186/188, Rh-105, Au-199) useful radiometals, coupled with the findings that the resulting complexes demonstrate high in vivo stability makes this approach useful in the development of radiolabeled biomolecules for applications in the design of tumor-specific radiopharmaceuticals.

Katti, Kattesh V.; Gali, Hariprasad; Volkert, Wynn A.

2004-08-24

69

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

PubMed

Phosphine gas, or hydrogen phosphide (PH3), is the most common insecticide applied to durable stored products worldwide and is routinely used in the United States for treatment of bulk-stored cereal grains and other durable stored products. Research from the late 1980s revealed low frequencies of resistance to various residual grain protectant insecticides and to phosphine in grain insect species collected in Oklahoma. The present work, which used the same previously established discriminating dose bioassays for phosphine toxicity as in the earlier study, evaluated adults of nine different populations of red flour beetle, Tribolium castaneum (Herbst), and five populations of lesser grain borer, Rhyzopertha dominica (F.) collected from different geographic locations in Oklahoma. One additional population for each species was a laboratory susceptible strain. Discriminating dose assays determined eight out of the nine T. castaneum populations, and all five populations of R. dominica, contained phosphine-resistant individuals, and highest resistance frequencies were 94 and 98%, respectively. Dose-response bioassays and logit analyses determined that LC99 values were approximately 3 ppm for susceptible and 377 ppm for resistant T. castaneum, and approximately 2 ppm for susceptible and 3,430 ppm for resistant R. dominica. The most resistant T. castaneum population was 119-fold more resistant than the susceptible strain and the most resistant R. dominica population was over 1,500-fold more resistant. Results suggest a substantial increase in phosphine resistance in these major stored-wheat pests in the past 21 yr, and these levels of resistance to phosphine approach those reported for other stored-grain pest species in other countries. PMID:22928286

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

2012-08-01

70

Ab initio molecular orbital study of the substituent effect on phosphine borane complexes  

NASA Astrophysics Data System (ADS)

Ab initio molecular orbital calculations have been used to study the substituent effect on H 3BPH nMe 3- n and Me 3- nH nBPH 3 ( n=0-3) phosphine-borane complexes. The ab initio results show that successive methyl substitution on the phosphine favours complex formation, contrary to successive methyl substitution on the borane. The natural bond orbitals partitioning scheme suggests that, in general, there is no correlation between the charge transfer and the complexation energies. It also shows the shortening of the P-H and P-C bond lengths, upon complexation, is due to the increasing `s' character of these bonds.

Anane, Hafid; Jarid, Abdellah; Boutalib, Abderrahim; Nebot-Gil, Ignacio; Tomás, Francisco

1998-11-01

71

Amino Acid derived phosphine-catalyzed enantioselective 1,4-dipolar spiroannulation of cyclobutenones and isatylidenemalononitrile.  

PubMed

Cyclobutenones have been explored as a new type of chiral 1,4-dipole four-carbon synthon, which readily undergoes organophosphine-mediated C?C bond cleavage and asymmetric intermolecular 1,4-dipolar spiroannulation with isatylidenemalononitrile in the presence of amino acid-derived chiral phosphine catalyst to furnish enantioenriched 3-spirocyclohexenone 2-oxindoles in good yield with up to 87?%?ee. To our knowledge, this is the first example of asymmetric transformation of cyclobutenones and the phosphine-catalyzed asymmetric 1,4-dipolar cycloaddition consisting of C?C bond activation is unprecedented. PMID:25630968

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

2015-03-01

72

Phosphine on Jupiter and Saturn from Cassini/CIRS  

NASA Astrophysics Data System (ADS)

The global distribution of phosphine (PH 3) on Jupiter and Saturn is derived using 2.5 cm -1 spectral resolution Cassini/CIRS observations. We extend the preliminary PH 3 analyses on the gas giants [Irwin, P.G.J., and 6 colleagues, 2004. Icarus 172, 37-49; Fletcher, L.N., and 9 colleagues, 2007a. Icarus 188, 72-88] by (a) incorporating a wider range of Cassini/CIRS datasets and by considering a broader spectral range; (b) direct incorporation of thermal infrared opacities due to tropospheric aerosols and (c) using a common retrieval algorithm and spectroscopic line database to allow direct comparison between these two gas giants. The results suggest striking similarities between the tropospheric dynamics in the 100-1000 mbar regions of the giant planets: both demonstrate enhanced PH 3 at the equator, depletion over neighbouring equatorial belts and mid-latitude belt/zone structures. Saturn's polar PH 3 shows depletion within the hot cyclonic polar vortices. Jovian aerosol distributions are consistent with previous independent studies, and on Saturn we demonstrate that CIRS spectra are most consistent with a haze in the 100-400 mbar range with a mean optical depth of 0.1 at 10 ?m. Unlike Jupiter, Saturn's tropospheric haze shows a hemispherical asymmetry, being more opaque in the southern summer hemisphere than in the north. Thermal-IR haze opacity is not enhanced at Saturn's equator as it is on Jupiter. Small-scale perturbations to the mean PH 3 abundance are discussed both in terms of a model of meridional overturning and parameterisation as eddy mixing. The large-scale structure of the PH 3 distributions is likely to be related to changes in the photochemical lifetimes and the shielding due to aerosol opacities. On Saturn, the enhanced summer opacity results in shielding and extended photochemical lifetimes for PH 3, permitting elevated PH 3 levels over Saturn's summer hemisphere.

Fletcher, L. N.; Orton, G. S.; Teanby, N. A.; Irwin, P. G. J.

2009-08-01

73

Copper-catalyzed tandem phosphination-decarboxylation-oxidation of alkynyl acids with H-phosphine oxides: a facile synthesis of ?-ketophosphine oxides.  

PubMed

The general method for the tandem phosphination-decarboxylation-oxidation of alkynyl acids under aerobic conditions has been developed. In the presence of CuSO4·5H2O and TBHP, the reactions provide a novel access to ?-ketophosphine oxides in good to excellent yields. This transformation allows the direct formation of a P-C bond and the construction of a keto group in one reaction. PMID:25855268

Zhang, Pengbo; Zhang, Liangliang; Gao, Yuzhen; Xu, Jian; Fang, Hua; Tang, Guo; Zhao, Yufen

2015-04-23

74

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

75

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

76

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

Microsoft Academic Search

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

Yu Mi Chang; Sung Cheol Yoon; Mijeong Han

2007-01-01

77

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...

78

Nickel phosphine catalysts with pendant amines for electrocatalytic oxidation of alcohols.  

PubMed

Nickel phosphine complexes with pendant amines have been found to be electrocatalysts for the oxidation of primary and secondary alcohols, with turnover frequencies as high as 3.3 s(-1). These complexes are the first electrocatalysts for alcohol oxidation based on non-precious metals, which will be critical for use in fuel cells. PMID:25753760

Weiss, Charles J; Wiedner, Eric S; Roberts, John A S; Appel, Aaron M

2015-03-24

79

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

80

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

81

Hessian fly mortality by phosphine-carbon dioxide fumigation and postharvest drying  

Technology Transfer Automated Retrieval System (TEKTRAN)

Hessian fly, Mayetiola destructor (Say), puparia, the stage of regulatory concern that may be found in weeds contaminating exported hay, may be controlled with a phosphine and carbon dioxide gas mixture dispensed from cylinders at a minimum dose of 750 ppm, temperature of 20°C (68°F) or higher, and ...

82

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

83

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

84

Fumigation with Phosphine for Postharvest Insect Control on Lettuce, Broccoli, and Strawberries  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

85

LOW TEMPERATURE PHOSPHINE FUMIGATION FOR POSTHARVEST PEST CONTROL ON FRESH VEGETABLES  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

86

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

87

Inheritance and Characterization of Strong Resistance to Phosphine in Sitophilus oryzae (L.)  

PubMed Central

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

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

2015-01-01

88

Highly enantioselective phosphination and hydrophosphonylation of azomethine imines: using chiral squaramide as a hydrogen bonding organocatalyst.  

PubMed

Enantioselective phosphination and hydrophosphonylation reactions between azomethine imines and diarylphosphine oxides or dialkyl phosphites were respectively developed by the use of a chiral squaramide as the hydrogen bonding organocatalyst, which afforded two types of phosphorus containing product in high yields with good to excellent enantioselectivities. PMID:25252601

Kong, Ling-Pei; Li, Nai-Kai; Zhang, Shao-Yun; Chen, Xiang; Zhao, Min; Zhang, Ya-Fei; Wang, Xing-Wang

2014-11-21

89

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

90

Effects of Outside Air Temperature on Movement of Phosphine Gas in Concrete Elevator Bins  

Technology Transfer Automated Retrieval System (TEKTRAN)

Studies that measured the movement and concentration of phosphine gas in upright concrete bins over time indicated that fumigant movement was dictated by air currents, which in turn, were a function of the difference between the average grain temperature and the average outside air temperature durin...

91

Five-coordinate [Pt(II)(bipyridine)2(phosphine)](n+) complexes: long-lived intermediates in ligand substitution reactions of [Pt(bipyridine)2](2+) with phosphine ligands.  

PubMed

The reaction of [Pt(N-N)2](2+) [N-N = 2,2'-bipyridine (bpy) or 4,4'-dimethyl-2,2'-bipyridine (4,4'-Me2bpy)] with phosphine ligands [PPh3 or PPh(PhSO3)2(2-)] in aqueous or methanolic solutions was studied by multinuclear ((1)H, (13)C, (31)P, and (195)Pt) NMR spectroscopy, X-ray crystallography, UV-visible spectroscopy, and high-resolution mass spectrometry. NMR spectra of solutions containing equimolar amounts of [Pt(N-N)2](2+) and phosphine ligand give evidence for rapid formation of long-lived, 5-coordinate [Pt(II)(N-N)2(phosphine)](n+) complexes. In the presence of excess phosphine ligand, these intermediates undergo much slower entry of a second phosphine ligand and loss of a bpy ligand to give [Pt(II)(N-N)(phosphine)2](n+) as the final product. The coordination of a phosphine ligand to the Pt(II) ion in the intermediate [Pt(N-N)2(phosphine)](n+) complexes is supported by the observation of (31)P-(195)Pt coupling in the (31)P NMR spectra. The 5-coordinate nature of [Pt(bpy)2{PPh(PhSO3)2}] is confirmed by X-ray crystallography. X-ray crystal structural analysis shows that the Pt(II) ion in [Pt(bpy)2{PPh(PhSO3)2}]·5.5H2O displays a distorted square pyramidal geometry, with one bpy ligand bound asymmetrically. These results provide strong support for the widely accepted associative ligand substitution mechanism for square planar Pt(II) complexes. X-ray structural characterization of the distorted square planar complex [Pt(bpy)(PPh3)2](ClO4)2 confirms this as the final product of the reaction of [Pt(bpy)2](2+) with PPh3 in CD3OD. The results of density functional calculations on [Pt(bpy)2](2+), [Pt(bpy)2(phosphine)](n+), and [Pt(bpy)(phosphine)2](n+) indicate that the bonding energy follows the trend of [Pt(bpy)(phosphine)2](n+) > [Pt(bpy)2(phosphine)](n+) > [Pt(bpy)2](2+) for stability and that the formation reactions of [Pt(bpy)2(phosphine)](n+) from [Pt(bpy)2](2+) and [Pt(bpy)(phosphine)2](n+) from [Pt(bpy)2(phosphine)](n+) are energetically favorable. These calculations suggest that the driving force for the formation of [Pt(bpy)(phosphine)2](n+) from [Pt(bpy)2](2+) is the formation of a more energetically favorable product. PMID:24654797

Lo, Warrick K C; Cavigliasso, Germán; Stranger, Robert; Crowley, James D; Blackman, Allan G

2014-04-01

92

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

E-print Network

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

Smith, Sean W.

93

Phosphinic peptide analogues as potent inhibitors of Corynebacterium rathayii bacterial collagenase.  

PubMed

Pseudo-substrate analogues of collagenase from Corynebacterium rathayii, in which the scissile peptide bond is replaced by a phosphinic moiety, were synthesized and evaluated as inhibitors of this enzyme. The phosphinic tetrapeptide, Z-Phe-psi(PO2CH2)-Gly-Pro-Nle (1), was found to be a potent inhibitor of collagenase with a Ki value of 8 nM. Increasing the length of the phosphinic-containing inhibitors from tetra- to hepta-peptide size further improves the potency of these compounds. The heptapeptide analogue, Z-Phe-Gly-Pro-Phe-psi(PO2CH2)-Gly-Pro-Nle-OMe, with a Ki value of 0.6 nM, is the most potent inhibitor reported to date for bacterial collagenases. A comparison between the phosphinic analogue Z-Phe-psi(PO2CH2)-Gly-Pro-Nle (1) and the phosphonamide peptide Z-Phe-psi(PO2NH)-Gly-Pro-Nle (2) shows that for bacterial collagenase the replacement of a CH2 by an NH group results only in a modest increase in affinity from Ki = 8 nM for compound 1 to Ki = 6 nM for compound 2. Most of the phosphorus-containing inhibitors of this series are slow- or slow-tight-binding inhibitors with second-order rate constants for association and dissociation varying respectively for the kon values from 1 x 10(3) to 26 x 10(3) M-1.s-1 and for the koff values from 3 x 10(-4) to 2 x 10(-5) s-1. Interestingly, the lower affinity of the molecule containing a D residue in the P1 position of the inhibitor, compared with the molecule with an L residue in this position, is mainly the consequence of a lower rate constant for association of these D stereoisomers with the enzyme. This study demonstrates that phosphinic peptide analogues are potent inhibitors of a bacterial collagenase. The development of new phosphinic peptides should lead to the discovery of potent inhibitors of other zinc metalloproteases. Details of how the analogues were synthesized are given in Supplementary Publication SUP 50176 (14 pages), which has been deposited with the British Library Document Supply Centre, Boston Spa, Wetherby, W. Yorkshire LS23 7BQ, from whom copies can be obtained on the terms indicated in Biochem. J. (1994) 297, 9. PMID:7945258

Yiotakis, A; Lecoq, A; Nicolaou, A; Labadie, J; Dive, V

1994-10-01

94

Phosphine-catalyzed [4+2] annulations of 2-alkylallenoates and olefins: synthesis of multisubstituted cyclohexenes.  

PubMed

From our investigations on phosphine-catalyzed [4+2] annulations between ?-alkyl allenoates and activated olefins for the synthesis of cyclohexenes, we discovered a hexamethylphosphorous triamide (HMPT)-catalyzed [4+2] reaction between ?-alkyl allenoates 1 and arylidene malonates or arylidene cyanoacetates 2 that provides highly functionalized cyclohexenes 3 and 4 in synthetically useful yields (30-89%), with moderate to exclusive regioselectivity, and reasonable diastereoselectivity. Interestingly, the [4+2] annulations between the ?-alkyl allenoates 1 and the olefins 2 manifested a polarity inversion of the 1,4-dipole synthon 1, depending on the structure of the olefin, thus providing cyclohexenes 3 exclusively when using arylidene cyanoacetates. The polarity inversion of ?-alkyl allenoates from a 1,4-dipole A to B under phosphine catalysis can be explained by an equilibrium between the phosphonium dienolate C and the phosphorous ylide D. PMID:21739609

Tran, Yang S; Martin, Tioga J; Kwon, Ohyun

2011-08-01

95

Phosphine-Catalyzed [4+2] Annulations of 2-Alkylallenoates and Olefins: Synthesis of Multisubstituted Cyclohexenes  

PubMed Central

From our investigations on phosphine-catalyzed [4+2] annulations between ?-alkyl allenoates and activated olefins for the synthesis of cyclohexenes, we discovered a hexamethylphosphorous triamide (HMPT)-catalyzed [4+2] reaction between ?-alkyl allenoates 1 and arylidene malonates or arylidene cyanoacetates 2 that provides highly functionalized cyclohexenes 3 and 4 in synthetically useful yields (30–89%), with moderate to exclusive regioselectivity, and reasonable diastereoselectivity. Interestingly, the [4+2] annulations between the a-alkyl allenoates 1 and the olefins 2 manifested a polarity inversion of the 1,4-dipole synthon 1, depending on the structure of the olefin, thus providing cyclohexenes 3 exclusively when using arylidene cyanoacetates. The polarity inversion of ?-alkyl allenoates from a 1,4-dipole A to B under phosphine catalysis can be explained by an equilibrium between the phosphonium dienolate C and the phosphorous ylide D. PMID:21739609

Tran, Yang S.; Martin, Tioga J.

2014-01-01

96

Theoretical study of iridium complexes with phenylpyridine based ligands and phosphines.  

PubMed

Recently, iridium complexes with phenylpyridine based ligands and phosphines, Ir(C(see text for symbol)N)2 (PPh3)(CN), [(C(see text for symbol)N) = dfppy, dfMeppy] are reported as blue phosphorescent OLED materials. These iridium complexes have novel blue color and emit light at 441 nm to 439 nm. However, these complexes have low external quantum efficiency because they exhibit less MLCT than iridium complexes with phenylpyridine, and some other ancillary ligands. To improve quantum efficiency of iridium complexes with phenylpyridine based ligands and phosphines, a time dependent density functional theory (TDDFT) study of these phosphors was performed. Using these results, this paper discusses how the ancillary ligand influences the emission peak, as well as the metal to ligand charge transfer (MLCT) transition efficiency. PMID:21780496

Lee, Seung-Chan; Ham, Ho Wan; Kim, Young Sik

2011-05-01

97

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

98

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

SciTech Connect

Syntheses for new ligands based upon dibenzothiophene and dibenzothiophene sulfone platforms, decorated with phosphine oxide and methylphosphine oxide donor groups, are described. Coordination chem. of 4, 6- bis(diphenylphosphinoylmethyl) dibenzothiophene (8) , 4, 6- bis(diphenylphosphinoylmethyl) dibenzothiophene- 5, 5- dioxide (9) and 4, 6- bis(diphenylphosphinoyl) dibenzothiophene- 5, 5- dioxide (10) with lanthanide nitrates, Ln(NO3) 3 (H2O) n is outlined, and crystal structure detns. reveal a range of chelation interactions on Ln(III) ions. The HNO3 dependence of the solvent extn. performance of 9 and 10 in 1, 2- dichloroethane for Eu(III) and Am(III) is described and compared against the extn. behavior of related dibenzofuran ligands (2, 3; R = Ph) and n- octyl(phenyl) - N, N- diisobutylcarbamoylmethyl phosphine oxide (4) measured under identical conditions.

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

2014-01-01

99

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

Microsoft Academic Search

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

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

2010-01-01

100

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

Microsoft Academic Search

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).

Yu Mi Chang; Sung Cheol Yoon; Mijeong Han

2007-01-01

101

Extraction of phenols from water with tri-octyl phosphine oxide  

Microsoft Academic Search

Tri-octyl phosphine oxide (TOPO) was examined as an extractant for removing phenol; the dihydric phenols catechol, resorcinol, and hydroquinone; and the trihydric phenols pyrogallol, phloroglucinol, and 1,2,4-benzenetriol from water. Distribution coefficients were measured and results modelled for extractions with different diluents, solvent compositions, temperatures, and extractant-to-solute stoichiometric ratios. Modelling of the results indicates that the extraction mechanism is complicated, with

MacGlashan

1982-01-01

102

Flow Heck reactions using extremely low loadings of phosphine-free palladium acetate.  

PubMed

High-yielding Heck reactions are demonstrated using 0.05 mol % Pd(OAc)2 without phosphine ligands. These reactions are run in a mesoscale flow reactor which allows precise control of reaction times and temperatures. Profiling yield and selectivity versus Pd loading shows 500 ppm to be optimal for aryl iodides; higher loadings favor side reactions caused by Pd(II) species. Aryl halides are examined via concise Design of Experiment to expand the scope and optimize conditions. PMID:23937686

Cyr, Patrick; Deng, Stella T; Hawkins, Joel M; Price, Kristin E

2013-09-01

103

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

104

Nickel and palladium complexes of pyridine?phosphine ligands and their use in ethene oligomerization  

Microsoft Academic Search

New pyridine-phosphine ligands of general structure 2-[2-(diarylphosphino)ethyl]pyridine were developed. The phosphorus substituents in these bidentates are 2-tolyl, 2-anisyl, and mesityl. The ligands could be conveniently synthesized in good yields. The nickel dichloride complexes of the ligands are paramagnetic. The metal centers have a distorted tetrahedral geometry, as was evident from the crystal structures and the magnetic moments in solution. The

Jitte Flapper; Huub Kooijman; Martin Lutz; Anthony L. Spek; Piet W. N. M. van Leeuwen; Cornelis J. Elsevier; Paul C. J. Kamer

2009-01-01

105

Nickel and palladium complexes of pyridine?phosphine ligands as ethene oligomerization catalysts  

Microsoft Academic Search

Pyridine?phosphine ligands 1?5 have been used to prepare neutral nickel dichloride complexes, neutral methylpalladium chloride complexes, and cationic methylpalladium complexes. The ligands consist of a diphenylphosphine and a pyridine moiety and differ in the backbone connecting those donor groups. Nickel complexes 9?13 are paramagnetic complexes, and they were characterized by elemental analysis, high-resolution mass spectrometry, and, for 10 and 12,

Jitte Flapper; Huub Kooijman; Martin Lutz; Anthony L. Spek; Piet W. N. M. van Leeuwen; Cornelis J. Elsevier; Paul C. J. Kamer

2009-01-01

106

The meridional phosphine distribution in Saturn's upper troposphere from Cassini/CIRS observations  

NASA Astrophysics Data System (ADS)

The Cassini Composite Infrared Spectrometer (CIRS) has been used to derive the vertical and meridional variation of temperature and phosphine (PH 3) abundance in Saturn's upper troposphere. PH 3 has a significant effect on the measured radiances in the thermal infrared and between May 2004 and September 2005 CIRS recorded thousands of spectra in both the far (10-600 cm -1) and mid (600-1400 cm -1) infrared, at a variety of latitudes covering the southern hemisphere. Low spectral resolution (15 cm -1) data has been used to constrain the temperature structure of the troposphere between 100 and 500 mbar. The vertical distributions of phosphine and ammonia were retrieved from far-infrared spectra at the highest spectral resolution (0.5 cm -1), and lower resolution (2.5 cm -1) mid-infrared data were used to map the meridional variation in the abundance of phosphine in the 250-500 mbar range. Temperature variations at the 250 mbar level are shown to occur on the same scale as the prograde and retrograde jets in Saturn's atmosphere [Porco, C.C., and 34 colleagues, 2005. Science 307, 1243-1247]. The PH 3 abundance at 250 mbar is found to be enhanced at the equator when compared with mid-latitudes. At mid latitudes we see anti-correlation between temperature and PH 3 abundance at 250 mbar, phosphine being enhanced at 45° S and depleted at 25 and 55° S. The vertical distribution is markedly different polewards of 60-65° S, with depleted PH 3 at 500 mbar but a slower decline in abundance with altitude when compared with the mid-latitudes. This variation is similar to the variations of cloud and aerosol parameters observed in the visible and near infrared, and may indicate the subsidence of tropospheric air at polar latitudes, coupled with a diminished sunlight penetration depth reducing the rate of PH 3 photolysis in the polar region.

Fletcher, L. N.; Irwin, P. G. J.; Teanby, N. A.; Orton, G. S.; Parrish, P. D.; Calcutt, S. B.; Bowles, N.; de Kok, R.; Howett, C.; Taylor, F. W.

2007-05-01

107

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

Microsoft Academic Search

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

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

2010-01-01

108

Perfluorinated phosphine oxide and sulfides as extractants for heavy metals and radionuclides.  

PubMed

New highly fluorinated monodentate and bidentate phosphine oxide compounds of the type {CF(3)(CF(2))(n)CH(2)CH(2)}(3)PO (n = 5, 9) and [{CF(3)(CF(2))(5)CH(2)CH(2)}(2)P(O)CH(2)CH(2)P(O){CH(2)CH(2)(CF(2))(5)CF(3)}] have been prepared. Their ability to extract a number of metals and radionuclides from aqueous solutions into perfluorinated solvents has been established and the extractable species investigated. All extractants extract the metals As(V), Cd(II), Co(II), Cr(VI), Hg(II), Pb(II), and Sn(II) with >75% removal. In addition, the radioisotopes (90)Sr(II), (133)Ba(II), and U(VI) have been investigated, whilst (59)Fe(III) has been used to model the extraction of plutonium. (133)Ba(II) shows a high distribution ratio for monodentate phosphine oxides, whilst for UO(2)(2+) and (59)Fe(III) bidentate phosphine oxides are superior. PMID:21723658

Baker, Robert J; Fuchs, Julia; Richards, Amanda J; Ogilvie, Helen V

2011-10-01

109

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

SciTech Connect

Phosphine oxide substitution of small molecules with high triplet exciton energies allows development of vacuum sublimable, electron transporting host materials for blue OLEDs. Heteroaromatic building blocks (carbazole, dibenzofuran and dibenzothiophene) with ET ~ 3 eV were incorporated into phosphine oxide (PO) structures. External quantum efficiencies (EQEs) at lighting brightness (i.e., 800 cd/m2) reached as high as 9.8% at 5.2V for OLEDs using the heteroaromatic PO hosts doped with the sky blue phosphor, iridium(III)bis(4,6-(di-fluorophenyl)-pyridinato-N,C2’) picolinate (FIrpic). Comparing device properties at a similar current density (i.e., J = 13 mA/cm2) showed the dibenzothiophene-bridged PO compound exhibits the highest EQEs and lowest operating voltages at all phosphor dopant levels. These results are explained with respect to the effects of the inductive phosphine oxide substituents on electrochemical, photophysical and electroluminescence properties of the substituted heteroaromatic building blocks.

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

2007-11-19

110

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

111

Palladium-catalyzed asymmetric phosphination. Scope, mechanism, and origin of enantioselectivity.  

PubMed

Asymmetric cross-coupling of aryl iodides (ArI) with secondary arylphosphines (PHMe(Ar'), Ar' = (2,4,6)-R3C6H2; R = i-Pr (Is), Me (Mes), Ph (Phes)) in the presence of the base NaOSiMe3 and a chiral Pd catalyst precursor, such as Pd((R,R)-Me-Duphos)(trans-stilbene), gave the tertiary phosphines PMe(Ar')(Ar) in enantioenriched form. Sterically demanding secondary phosphine substituents (Ar') and aryl iodides with electron-donating para substituents resulted in the highest enantiomeric excess, up to 88%. Phosphination of ortho-substituted aryl iodides required a Pd(Et-FerroTANE) catalyst but gave low enantioselectivity. Observations during catalysis and stoichiometric studies of the individual steps suggested a mechanism for the cross-coupling of PhI and PHMe(Is) (1) initiated by oxidative addition to Pd(0) yielding Pd((R,R)-Me-Duphos)(Ph)(I) (3). Reversible displacement of iodide by PHMe(Is) gave the cation [Pd((R,R)-Me-Duphos)(Ph)(PHMe(Is))][I] (4), which was isolated as the triflate salt and crystallographically characterized. Deprotonation of 4-OTf with NaOSiMe3 gave the phosphido complex Pd((R,R)-Me-Duphos)(Ph)(PMeIs) (5); an equilibrium between its diastereomers was observed by low-temperature NMR spectroscopy. Reductive elimination of 5 yielded different products depending on the conditions. In the absence of a trap, the unstable three-coordinate phosphine complex Pd((R,R)-Me-Duphos)(PMeIs(Ph)) (6) was formed. Decomposition of 5 in the presence of PhI gave PMeIs(Ph) (2) and regenerated 3, while trapping with phosphine 1 during catalysis gave Pd((R,R)-Me-Duphos)(PHMe(Is))2 (7), which reacted with PhI to give 3. Deprotonation of 1:1 or 1.4:1 mixtures of cations 4-OTf gave the same 6:1 ratio of enantiomers of PMeIs(Ph) (2), suggesting that the rate of P inversion in 5 was greater than or equal to the rate of reductive elimination. Kinetic studies of the first-order reductive elimination of 5 were consistent with a Curtin-Hammett-Winstein-Holness (CHWH) scheme, in which pyramidal inversion at the phosphido ligand was much faster than P-C bond formation. The absolute configuration of the phosphine (SP)-PMeIs(p-MeOC6H4) was determined crystallographically; NMR studies and comparison to the stable complex 5-Pt were consistent with an RP-phosphido ligand in the major diastereomer of the intermediate Pd((R,R)-Me-Duphos)(Ph)(PMeIs) (5). Therefore, the favored enantiomer of phosphine 2 appeared to be formed from the major diastereomer of phosphido intermediate 5, although the minor intermediate diastereomer underwent P-C bond formation about three times more rapidly. The effects of the diphosphine ligand, the phosphido substituents, and the aryl group on the ratio of diastereomers of the phosphido intermediates Pd(diphos*)(Ar)(PMeAr'), their rates of reductive elimination, and the formation of three-coordinate complexes were probed by low-temperature 31P NMR spectroscopy; the results were also consistent with the CHWH scheme. PMID:17474744

Blank, Natalia F; Moncarz, Jillian R; Brunker, Tim J; Scriban, Corina; Anderson, Brian J; Amir, Omar; Glueck, David S; Zakharov, Lev N; Golen, James A; Incarvito, Christopher D; Rheingold, Arnold L

2007-05-30

112

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

PubMed

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

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

2011-10-19

113

Effects of phosphine and methyl bromide fumigation on the volatile flavor profile and sensory quality of dry cured ham.  

PubMed

In separate experiments, randomized complete block designs with three replications were utilized to evaluate the effects of phosphine (PH(3)) (0, 200 and 1000ppm for 48h) and methyl bromide (MB) (0, 4, 8, 16, and 32mg/L for 48h) fumigation concentration on the volatile flavor compound concentrations in dry cured ham. Minimal differences existed (P>0.05) in the presence and concentration of aroma active compounds in both PH(3) and MB fumigated hams but sulfur and oxidation compounds were more prevalent (P<0.05) in the fumigated treatments when compared to the control. As phosphine fumigation concentration increased, the residual concentration of phosphine also increased in the hams (P<0.05), but all samples contained levels that are lower than the legal limit of phosphine allowed in stored food products (0.01ppm) in the United States. A triangle test (n=56) indicated that consumers could not discriminate (P>0.75) between the control hams and those that were fumigated with PH(3). Minimal aroma/flavor differences existed among MB, PH3 and control hams, and dry cured ham that was fumigated with PH(3) was safe for consumption based on residual phosphine concentrations in the meat tissue. PMID:20554396

Sekhon, R K; Schilling, M W; Phillips, T W; Aikins, M J; Hasan, M M; Corzo, A; Mikel, W B

2010-10-01

114

Water-soluble phosphines for direct labeling of peptides with technetium and rhenium: insights from electrospray mass spectrometry.  

PubMed

Direct labeling of salmon calcitonin (sCT) is possible in one step using water-soluble phosphines (sulfonated triphenylphosphines) as the reducing agent both for disulfide and for pertechnetate. Phosphines were the most efficient reducing agent for disulfide bonds among those examined. The phosphines both reduced the pertechnetate to Tc(III), and contributed to the technetium coordination sphere in the labeled product. In contrast, the phosphines did not reduce rhenium below oxidation state V, nor did they participate in the rhenium coordination sphere in the labeled peptide. Instead, the expected oxorhenium(V) moiety was incorporated. Both Tc and Re labeling processes gave rise to dimers with two peptides linked by the metal center, as well as simple monomeric species. Positive mode electrospray mass spectrometry not only revealed the presence of phosphine bound to technetium and oxygen bound to rhenium in the metallopeptides but also revealed the oxidation states of the metals. Electrospray mass spectrometry is proving to be an exceptionally valuable technique for characterizing radiopharmaceuticals. Although the one-step direct labeling method described gives mixed products and poor receptor affinity when applied to the small peptide sCT, it might be readily adapted to monoclonal antibodies. PMID:16029035

Greenland, William E P; Blower, Philip J

2005-01-01

115

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

116

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

117

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

NASA Astrophysics Data System (ADS)

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.

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

2015-02-01

118

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

PubMed

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

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

2012-01-11

119

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

NASA Astrophysics Data System (ADS)

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

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

2008-06-01

120

Phosphines with 2-imidazolium and para-phenyl-2-imidazolium moieties — synthesis and application in two-phase catalysis  

Microsoft Academic Search

Deprotonation of 1-n-butyl-3-methyl-imidazolium chloride or hexafluorophosphate with n-butyl lithium and subsequent reaction of the intermediate 2,3-dihydro-imidazol-2-ylidene with diphenylchlorophosphine affords the 2-imidazolium phosphines 3a or 3b. The phosphine 4 with a para-phenylene spacer between the imidazolyl moiety and the phosphorus atom has been obtained by Kosugi–Stille coupling between 2-tri-n-butyl-stannyl-1-methylimidazole and 4-fluoroiodobenzene followed by nucleophilic substitution of fluorine with PPh2K. The X-ray

David J Brauer; Konstantin W Kottsieper; Christian Liek; Othmar Stelzer; Horst Waffenschmidt; Peter Wasserscheid

2001-01-01

121

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

122

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

PubMed Central

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

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

2015-01-01

123

Tricarbonyl­bis(tricyclo­hexyl­phosphine-?P)ruthenium(0) toluene solvate  

PubMed Central

The title compound, [Ru(C18H33P)2(CO)3]·C7H8, shows a distorted trigonal-bipyramdial coordination around the central Ru atom, with the two phosphine ligands occupying the axial positions. Two toluene mol­ecules per asymmetric unit with site-occupation factors of 0.5 are observed. One of them forces two of the CO ligands to enclose a wider C—Ru—C bond angle [127.5?(3)°] than in the solvent-free crystal structure of [Ru(PCy3)2(CO)3] (Cy is cyclo­hexyl). PMID:21580893

Nader, Andreas; Görls, Helmar; Imhof, Wolfgang

2008-01-01

124

Phosphine-catalyzed [4 + 2] annulation of ?-substituent allenoates: facile access to functionalized spirocyclic skeletons.  

PubMed

The first phosphine-catalyzed [4 + 2] annulation of ?-substituted allenoates with 2-arylidene-1H-indene-1,3(2H)-diones is disclosed. In the reaction, the ?-substituted allenoate serves as a new type of 1,4-dipolar synthon; this broadens the application of ?-substituted allenoates. This method also offers a powerful approach to the construction of highly substituted spiro[4.5]dec-6-ene skeletons in excellent yields, and with complete regioselectivity and high diastereoselectivity. PMID:23742187

Li, Erqing; Huang, You; Liang, Ling; Xie, Peizhong

2013-06-21

125

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

126

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

127

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

PubMed

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

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

2015-01-21

128

Phosphinic acid functionalized carbon nanotubes for sensitive and selective sensing of chromium(VI).  

PubMed

Single-walled carbon nanotubes (SWCNTs) have been functionalized with a phosphinic acid derivative 'bis(2,4,4-trimethylpentyl) phosphinic acid' (PA/d). It has been achieved by treating the chlorinated SWCNTs with PA/d at 80°C. Successful functionalization and different nanomaterial properties have been investigated by UV-vis-NIR, FTIR, Raman spectroscopy, AFM and FE-SEM. PA/d conjugated SWCNTs (CNT-PA) are dispersible in some common organic solvents, e.g. CH2Cl2, DMF, CHCl3, and THF. The 'CNT-PA' complex was spin-casted on boron doped silicon wafer. Thus fabricated sensing electrode is demonstrated for sensitive and selective electrochemical sensing of chromium(VI) ions. A linear response is obtained over a wide range of Cr(VI) concentration (0.01-10 ppb). The sensor's sensitivity and the limit of detection are observed to be 35 ± 4 nA/ppb and 0.01 ppb, respectively. The practical utility of the proposed sensor is demonstrated by determining the Cr(VI) concentration in an industrial effluent sample and an underground water sample. PMID:25016454

Deep, Akash; Sharma, Amit L; Tuteja, Satish K; Paul, A K

2014-08-15

129

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

130

Pillar[5]arenes bearing phosphine oxide pendents as Hg(2+) selective receptors.  

PubMed

Pillar[5]arenes bearing ten phosphine oxide groups (1a-e), as analogs of their corresponding calix[4]arene-based phosphine oxide, have demonstrated intriguing recognition performance for some representative heavy metal cations including Co(2+), Cu(2+), Ni(2+), Zn(2+), Cd(2+), Pb(2+), Ag(2+) and Hg(2+) compared to their acyclic species (2a-e). Their extraction abilities toward these cations were evaluated by the solvent extraction method. The extraction results revealed that 1a-e were efficient and selective cation receptors for Hg(2+) over other selected cations. In addition, the complexation behavior of 1a-e for Hg(2+) was also investigated by using NMR and UV-vis techniques. The pillarareen receptors have been first used in the determination of inorganic mercury in natural water by inductively coupled plasma atomic emission spectrometry (ICP-AES), after back-extracting into aqueous phase with 3 mol L(-1) HCl and 1% CS(NH2)2 solution. PMID:24840451

Jia, Yiming; Fang, Yuyu; Li, Yan; He, Lutao; Fan, Wenhua; Feng, Wen; Yang, Yuanyou; Liao, Jiali; Liu, Ning; Yuan, Lihua

2014-07-01

131

Tri(pyridylmethyl)phosphine: the elusive congener of TPA shows surprisingly different coordination behavior.  

PubMed

Tri(pyridylmethyl)phosphine (TPPh), the remarkably elusive congener of tri(pyridylmethyl)amine (TPA), has been prepared, as well as the relative tri(N-methyl-pyridylamino)phosphine (TPAMP). The coordination properties of these new ligands have been evaluated for chromium(III), iron(II), and ruthenium(II) complexes and compared with the related TPA complexes. In all cases, a different coordination behavior has been observed whereby TPPh and TPAMP always act as tridentate ligands. A chromium(III) complex [Cr(TPPh)Cl3] has been prepared, which has shown low ethylene oligomerization activity. Octahedral low spin iron(II) complexes [Fe(TPPh)2](2+) and [Fe(TPAMP)2](2+) were obtained with two ligands bound to the metal center. Ruthenium(II) chloro complexes of TPA and TPPh undergo ligand exchange reactions in acetonitrile, and the ruthenium(II) complex [Ru(MeCN)2(TPA)](2+) can be oxidized by m-CPBA in acetonitrile to give a transient ruthenium(IV) oxo complex [Ru(O)(MeCN)(TPA)](2+). Attempts to generate high valent ruthenium(IV) oxo TPPh or TPAMP complexes could not be achieved, probably due to insufficient stabilization by these strong field ligands. PMID:23701515

Whiteoak, Christopher J; Nobbs, James D; Kiryushchenkov, Evgeny; Pagano, Sandro; White, Andrew J P; Britovsek, George J P

2013-06-17

132

Theoretical studies of blue phosphorescent iridium(III) complexes with phenylpyrazole and phosphines.  

PubMed

New blue emitting mixed ligand iridium(III) complexes comprising one cyclometalating, two phosphines trans to each other such as Ir(dppz)(PPhMe2)2(H)(C1) and Ir(dppz)(PPhMe2)2(H)(CN), [dppz = 3,5-Diphenylpyrazole] were studied to tune the phosphorescence wavelength to the deep blue region and to enhance the luminescence efficiencies. To achieve deep blue emission and increase the emission efficiency, the following must occur: (1) substitution of phenyl group on the 3-position of the pyrazole ring that lower the triplet energy enough that the quenching channel is not thermally accessible, (2) changing ancillary ligands coordinated to iridium atom to phosphine and cyano groups known as very strong field ligands. Using the density functional theory (DFT) and time-dependent DFT method calculations on the ground and excited states of the complexes, we have studied how the ancillary ligand influences the emission peak as well as MLCT transition efficiency. It is showed that the strong-field ancillary ligand such as CN, PPhMe2 alters the energy gap mainly by changing the highest occupied molecular orbitals (HOMO) energy level. Their inclusion in the coordination sphere can increase the energy gap to achieve the hypsochromic shift in emission color and also lower the triplet energy level to avoid the thermal quenching. PMID:22852392

Park, Se Won; Chang, Dong Min; Kim, Young Sik

2012-05-01

133

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

134

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

SciTech Connect

We used classical molecular dynamics (MD) simulations to investigate the nanoscale morphology and proton transport properties of perfluoro phosphonic (FPA) and phosphinic acid (FPA-I) membranes as they are being considered for use in low temperature fuel cells. We systematically investigated these properties as a function of the hydration level. The changes in nanostructure, in transport dynamics of water and hydronium ions, and in water network percolation were extracted from MD simulations and compared with Nafion. Phosphonic and phosphinic acid moieties in FPA and FPA-I, have lower acidity than sulfonic acid in Nafion, yet the diffusion of water was observed to be faster in FPA and FPA-I than in Nafion, particularly at low hydration levels. However this did not give rise to notable differences in hydronium ion diffusion and water network percolation for these membranes over Nafion. Similar observations were also reported by our group recently in a study of perfluoro-sulfonyl imide membranes carrying stronger super-acids than sulfonic acid of Nafion. These findings together suggest no strong apparent correlation between the acidity strength of the functional acid groups and the dynamics of water and hydronium ions in hydrated polymer electrolyte membranes (PEMs) with similar fluorocarbon backbones and acidic group-carrying side chains. This work was supported by the US Department of Energy Basic Energy Sciences' Chemical Sciences, Geosciences & Biosciences Division. Pacific Northwest National Laboratory is operated by Battelle for the US Department of Energy.

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

2011-03-31

135

Phosphine-Catalyzed Hydration and Hydroalkoxylation of Activated Olefins: Use of a Strong Nucleophile to Generate a Strong Base  

E-print Network

in both the hydration and hydromethoxylation conditions. Using 1 and methyl vinyl ketone as our standardPhosphine-Catalyzed Hydration and Hydroalkoxylation of Activated Olefins: Use of a Strong ketones are ubiquitous intermediates and targets in organic synthesis. They are typically prepared either

Toste, Dean

136

SEPARATION OF PHENOLS FROM DILUTE AQUEOUS SOLUTION BY USE OF TRI-o-OCTYL PHOSPHINE OXIDE AS EXTRACTANT  

Microsoft Academic Search

Trioctyl phosphine oxide (TOPO) is examined as an extractant for phenol and other phenolic compounds. Equilibrium distribution coefficients have been measured for extraction of phenol, dihydroxybenzenes, and trihydroxybenzenes by solvents composed of TOPO in various diluents. Results are interpreted in terms of a model based upon complexation stoichiometry, allowing for solvation of uncomplexed solute as well. TOPO is a strong

John D. MacGlashan; James L. Bixby; C. Judson King

1985-01-01

137

Polymer-Supported Phosphine-Halogen Complexes - 2 A New Facile Way for Esterification of Carboxylic Acids  

Microsoft Academic Search

The easily available complexes of polystyryl diphenyl phosphine with halogens are convenient condensating agents in the esterification of carboxylic acids under very mild conditions. The isolation of the ester by a simple filtration and evaporation process is a further interesting feature of this reaction.

Romualdo Caputo; Elvira Corrado; Carla Ferreri; Giovanni Palumbo

1986-01-01

138

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

139

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

140

Phosphine resistance in the rust red flour beetle, Tribolium castaneum (Coleoptera: Tenebrionidae): inheritance, gene interactions and fitness costs.  

PubMed

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

141

Comparison of Dithiophosphinic and Phosphinic Acid Derivatives for Minor Actinide Extraction  

SciTech Connect

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

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

2008-03-01

142

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

SciTech Connect

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

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

2008-03-01

143

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 constraints indicate that PH3 is significantly depleted at even deeper atmospheric levels (or = 500 mbar), implying an eddy diffusion coefficient for Saturn of 10 to the 4 cm sq/sec.

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

1985-01-01

144

Water-soluble hydroxyalkylated phosphines: examples of their differing behaviour toward ruthenium and rhodium.  

PubMed

The reaction of P(CH2OH)3 (I) and P(C6H5)(CH2OH)2 (II) with RuCl3 in methanol eliminates two equivalents of formaldehyde to yield the mixed tertiary and secondary phosphine complexes all-trans-[RuCl2(P(CH2OH)3)2(P(CH2OH)2H)2] (1) and [RuCl2(P(C6H5)(CH2OH)2)2(P(C6H5)(CH2OH)H)2] (2), respectively. There is a high degree of hydrogen-bonding interactions between the hydroxymethyl groups in 1 and 2, although the phenyl groups of the latter reduce the extent of the network compared to 1. The generation of these mixed secondary and tertiary phosphine complexes is unprecedented. Under the same reaction conditions, the tris(hydroxypropyl)phosphine III formed no ruthenium complex. The reaction of P(CH2OH)3, P(C6H5)(CH2OH)2 and P{(CH2)3OH}3 with [RhCl(1,5-cod)]2 in an aqueous/dichloromethane biphasic medium yielded [RhH2(P(CH2OH)3)4]+ (3), [RhH2(P(C6H5)(CH2OH)2)4]+ (4) and [Rh(P(C6H5)(CH2OH)2)4]+ (5) and [Rh(P{(CH2)3OH}3)4]+ (6), respectively. Treating 5 with dihydrogen rapidly gave 4. The hydroxypropyl compound 6 formed the corresponding dihydride much more slowly in aqueous solution, although [RhH2(P{(CH2)3OH}3)4]+ (7) was readily formed by reaction with dihydrogen. Two separate reaction pathways are therefore involved; for P(CH2OH)3 and to a lesser extent P(C6H5)(CH2OH)2, the hydride source in the product is likely to be the aqueous solvent or the hydroxyl protons, whilst for P{(CH2)3OH}3 an oxidative addition of H2 is favoured. The protic nature of and was illustrated by the H-D exchange observed in d2-water. Dihydrides 3 and 4 reacted with carbon monoxide to yield the dicarbonyl cations [Rh(CO)2(P(CH2OH)3)3]+ (8) and [Rh(CO)2(P(C6H5)(CH2OH)2)3]+ (9). The analogous experiment with [RhH2(P{(CH2)3OH}3)4]+ resulted in phosphine exchange, although our experimental evidence points to the possibility of more than one fluxional process in solution. PMID:15573173

Higham, Lee J; Whittlesey, Michael K; Wood, Paul T

2004-12-21

145

The reaction of tin(IV) iodide with phosphines: formation of new halotin anions.  

PubMed

The reaction of SnI(4) with each of a primary, secondary and tertiary phosphine has been investigated and in none of the cases are simple adducts formed. With Cy(3)P, [Cy(3)PI](+) salts of both [SnI(3)](-) (1) and [SnI(5)](-) (2) are isolated arising from reactions involving both reduction at tin and halogen transfer. With the secondary and primary amines Ph(2)PH and CyPH(2), respectively, additional HI elimination reactions occur and the salts [Ph(2)PH(2)](+)(6)[Sn(3)I(12)](6-) (3), [Ph(2)PH(2)](+)(2)[SnI(6)](2-) (4) and [CyPH(3)](+)(2)[SnI(4)](2-) (5) have been isolated. Compounds 1-5 have been characterised crystallographically. PMID:20023871

Apostolico, Leonardo; Kociok-Köhn, Gabriele; Molloy, Kieran C; Blackman, Christopher S; Carmalt, Claire J; Parkin, Ivan P

2009-12-21

146

Time-dependent density functional theory study of the luminescence properties of gold phosphine thiolate complexes.  

PubMed

The origin of the emission of the gold phosphine thiolate complex (TPA)AuSCH(CH3)2 (TPA = 1,3,5-triaza-7-phosphaadamantanetriylphosphine) is investigated using time-dependent density functional theory (TDDFT). This system absorbs light at 3.6 eV, which corresponds mostly to a ligand-to-metal transition with some interligand character. The P-Au-S angle decreases upon relaxation in the S1 and T1 states. Our calculations show that these two states are strongly spin-orbit coupled at the ground state geometry. Ligand effects on the optical properties of this complex are also discussed by looking at the simple AuP(CH3)3SCH3 complex. The excitation energies differ by several tenths of an electronvolt. Excited state optimizations show that the excited singlet and triplet of the (TPA)AuSCH(CH3)2 complex are bent. On the other hand, the Au-S bond breaks in the excited state for the simple complex, and TDDFT is no longer an adequate method. The excited state energy landscape of gold phosphine thiolate systems is very complex, with several state crossings. This study also shows that the formation of the [(TPA)AuSCH(CH3)2]2 dimer is favorable in the ground state. The inclusion of dispersion interactions in the calculations affects the optimized geometries of both ground and excited states. Upon excitation, the formation of a Au-Au bond occurs, which results in an increase in energy of the low energy excited states in comparison to the monomer. The experimentally observed emission of the (TPA)AuSCH(CH3)2 complex at 1.86 eV cannot be unambiguously assigned and may originate from several excited states. PMID:25793466

Guidez, Emilie B; Aikens, Christine M

2015-04-01

147

Strong ligand field effects of blue phosphorescent Ir(III) complexes with phenylpyrazole and phosphines.  

PubMed

In the paper, we describe new Ir complexes for achieving efficient blue phosphorescence. New blue-emitting mixed-ligand Ir complexes comprising one cyclometalating, two phosphines trans to each other such as Ir(dppz)(PPh3)2(H)(L) (Ll= Cl, NCMe+, CN), [dppz = 3,5-Diphenylpyrazole] were synthesized and studied to tune the phosphorescence wavelength to the deep blue region and to enhance the luminescence efficiencies. To gain insight into the factors responsible for the emission color change and the variation of luminescence efficiency, we investigate the electron-withdrawing capabilities of ancillary ligands using DFT and TD-DFT calculations on the ground and excited states of the complexes. To achieve deep blue emission and increase the emission efficiency, (1) we substitute the phenyl group on the 3-position of the pyrazole ring that lowers the triplet energy enough that the quenching channel is not thermally accessible and (2) change the ancillary ligands coordinated to iridium atom to phosphine and cyano groups known as very strong field ligands. Their inclusion in the coordination sphere can increase the HOMO-LUMO gap to achieve the hypsochromic shift in emission color and lower the HOMO and LUMO energy level, which causes a large d-orbital energy splitting and avoids the quenching effect to improve the luminescence efficiency. The maximum emission spectra of Ir(dppz)(PPh3)2(H)(CI) and Ir(dppz)(PPh3)2(H)(CN) were in the ranges of 439, 432 nm, respectively. PMID:22849126

Park, Se Won; Ham, Ho Wan; Kim, Young Sik

2012-04-01

148

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

149

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

PubMed

Dialkyl phosphinate acids (DPAs) are the hydrolysates of aluminum dialkyl phosphinates (ADPs), one class of emerging phosphorus flame retardants since brominated flame retardants have been gradually phased out in recent years. It has been found that once dissolved in water, ADPs are completely hydrolyzed and exist as DPAs. However, there is no report on the determination of DPAs in environmental water samples. For the first time, we developed a method for the analysis of trace DPAs and ADPs in different environmental samples, including waters, soils and sediments. In this proposed method, MAX cartridges were employed for the purification, and ion chromatography (IC) tandem mass spectrometry (MS) method with large volume injection (200?L) and postcolumn addition of methanol and NH3·H2O were employed for the determination of DPAs and ADPs. The matrix effects were <16% for water samples and <25% for soil/sediment samples, which were greatly improved in comparison to the liquid chromatography (LC) tandem MS determination. Determined at three fortified levels of 0.02?g/L, 0.2?g/L and 1.0?g/L, the mean recoveries were from 75.8% to 110.2%, with an acceptable coefficient of variation (3.3-20%, n=6) for water samples. The limits of the method were 3.5-9.3ng/L for DPAs in environmental water samples, and 0.06-0.09?g/kg for DPAs and ADPs in soil and sediment samples. For soil and sediment samples, results determined by the present IC-MS method were in good agreement with that determined by LC-MS in our previous study. PMID:25836050

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

2015-05-15

150

High efficiency of cavity-based triaryl-phosphines in nickel-catalysed Kumada-Tamao-Corriu cross-coupling.  

PubMed

Combining diaryl-calixarenyl phosphines with [Ni(cod)(2)] resulted in highly active Kumada-Tamao-Corriu cross-coupling catalysts. With one of the ligands, TOFs up to 439,000 mol(ArBr) mol(Ni)(-1) h(-1) were observed in the reaction of 1-bromonaphthalene with PhMgBr. The systems were also found to be active at room temperature with aryl chlorides. PMID:21544285

Monnereau, Laure; Sémeril, David; Matt, Dominique

2011-06-21

151

Diagnostic Molecular Markers for Phosphine Resistance in U.S. Populations of Tribolium castaneum and Rhyzopertha dominica  

PubMed Central

Stored product beetles that are resistant to the fumigant pesticide phosphine (hydrogen phosphide) gas have been reported for more than 40 years in many places worldwide. Traditionally, determination of phosphine resistance in stored product beetles is based on a discriminating dose bioassay that can take up to two weeks to evaluate. We developed a diagnostic cleaved amplified polymorphic sequence method, CAPS, to detect individuals with alleles for strong resistance to phosphine in populations of the red flour beetle, Tribolium castaneum, and the lesser grain borer, Rhyzopertha dominica, according to a single nucleotide mutation in the dihydrolipoamide dehydrogenase (DLD) gene. We initially isolated and sequenced the DLD genes from susceptible and strongly resistant populations of both species. The corresponding amino acid sequences were then deduced. A single amino acid mutation in DLD in populations of T. castaneum and R. dominica with strong resistance was identified as P45S in T. castaneum and P49S in R. dominica, both collected from northern Oklahoma, USA. PCR products containing these mutations were digested by the restriction enzymes MboI and BstNI, which revealed presence or absence, respectively of the resistant (R) allele and allowed inference of genotypes with that allele. Seven populations of T. castaneum from Kansas were subjected to discriminating dose bioassays for the weak and strong resistance phenotypes. Application of CAPS to these seven populations confirmed the R allele was in high frequency in the strongly resistant populations, and was absent or at a lower frequency in populations with weak resistance, which suggests that these populations with a low frequency of the R allele have the potential for selection of the strong resistance phenotype. CAPS markers for strong phosphine resistance will help to detect and confirm resistant beetles and can facilitate resistance management actions against a given pest population. PMID:25826251

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

2015-01-01

152

Nickel and palladium complexes of pyridine-phosphine ligands bearing aromatic substituents and their behavior as catalysts in ethene oligomerization  

Microsoft Academic Search

Bidentate pyridine-phosphine ligands 1 of general structure 2-aryl-6-[2-(diphenylphosphino)ethyl]pyridine were developed, in which the aryl group is phenyl (a), 1-naphthyl (b), 9-phenanthryl (c), 9-anthracyl (d), and ferrocenyl (e). The influence of these substituents on the nickel and palladium complexes of the ligands and their ethene oligomerization behavior was studied. The largest influence was observed in species with a square-planar surrounded metal

Jitte Flapper; Leeuwen van P. W. N. M; Cornelis J. Elsevier; Paul C. J. Kamer

2009-01-01

153

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

PubMed

Phosphine, a widely used fumigant for the protection of stored grain from insect pests, kills organisms indirectly by inducing oxidative stress. High levels of heritable resistance to phosphine in the insect pest of stored grain, Rhyzopertha dominica have been detected in Asia, Australia and South America. In order to understand the evolution of phosphine resistance and to isolate the responsible genes, we have undertaken genetic linkage analysis of fully sensitive (QRD14), moderately resistant (QRD369) and highly resistant (QRD569) strains of R. dominica collected in Australia. We previously determined that two loci, rph1 and rph2, confer high-level resistance on strain QRD569, which was collected in 1997. We have now confirmed that rph1 is responsible for the moderate resistance of strain QRD369, which was collected in 1990, and is shared with a highly resistant strain from the same geographical region, QRD569. In contrast, rph2 by itself confers only very weak resistance, either as a heterozygote or as a homozygote and was not discovered in the field until weak resistance (probably due to rph1) had become ubiquitous. Thus, high-level resistance against phosphine has evolved via stepwise acquisition of resistance alleles, first at rph1 and thereafter at rph2. The semi-dominance of rph2 together with the synergistic interaction between rph1 and rph2 would have led to rapid selection for homozygosity. A lack of visible fitness cost associated with alleles at either locus suggests that the resistance phenotype will persist in the field. PMID:18270533

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

2008-05-01

154

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

155

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

156

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

NASA Astrophysics Data System (ADS)

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

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

2013-07-01

157

Catalytic Oxidation of Alcohol via Nickel Phosphine Complexes with Pendant Amines  

SciTech Connect

Nickel complexes were prepared with diphosphine ligands that contain pendant amines, and these complexes catalytically oxidize primary and secondary alcohols to their respective aldehydes and ketones. Kinetic and mechanistic studies of these prospective electrocatalysts were performed to understand what influences the catalytic activity. For the oxidation of diphenylmethanol, the catalytic rates were determined to be dependent on the concentration of both the catalyst and the alcohol. The catalytic rates were found to be independent of the concentration of base and oxidant. The incorporation of pendant amines to the phosphine ligand results in substantial increases in the rate of alcohol oxidation with more electron-donating substituents on the pendant amine exhibiting the fastest rates. We thank Dr. John C. Linehan, Dr. Elliott B. Hulley, Dr. Jonathan M. Darmon, and Dr. Elizabeth L. Tyson for helpful discussions. Research by CJW, PD, DLM, and AMA was supported by the US Department of Energy, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences & Biosciences. Research by MLH was supported as part of the Center for Molecular Electrocatalysis, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences. Pacific Northwest National Laboratory (PNNL) is a multiprogram national laboratory operated for DOE by Battelle.

Weiss, Charles J.; Das, Partha Pratim; Higgins, Deanna LM; Helm, Monte L.; Appel, Aaron M.

2014-09-05

158

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

159

C6, C7, and C8 perfluoroalkyl-substituted phosphinic acids.  

PubMed

Reaction of red phosphorus with RfI in a 1:2 molar ratio at 230 degrees C led to the formation of a mixture of (Rf)2PI and (Rf)PI2 (Rf = C6F13, C7F15, C8F17) in about a 70:30 ratio, respectively. These mixtures were separated by vacuum distillation. (Rf)2PI (Rf = C6F13, C7F15) are yellow liquids whereas (C8F17)2PI is a yellow solid. Oxidation of (Rf)2PI with excess NO2 led to (Rf)2P(O)OH (Rf = C6F13, C7F15, C8F17) in > 90% isolated yields after aqueous hydrolysis of the anhydride intermediates. These highly fluorinated phosphinic acids are white solids with sharp melting points and are highly soluble in methyl sulfoxide (DMSO) and 1,1,2-trichlorotrifluoroethane. However, solubility in chloroform and methylene dichloride is low. These perfluoroalkylphosphinic acids were characterized by IR, NMR (1H, 19F, and 31P), and mass spectra and elemental analysis. PMID:12526569

Singh, R P; Shreeve, J M

2000-04-17

160

Global Modeling of Phosphine (PH3) Spectra: 13 to 2.8 ?m  

NASA Astrophysics Data System (ADS)

In order to support remote sensing of Saturn and Jupiter, the infrared spectrum of PH3 was studied using high resolution (R>360000) laboratory spectra obtained with Fourier transform spectrometers. The line positions and intensities involving up to 21 sub-vibrational states were analyzed simultaneously using theoretical models developed in France and extended in Russia. The polyads considered were the Dyad (13 - 7.3 ?m), Pentad (5.9 - 3.8 ?m) and Octad (3.7 - 3.1 ?m). The improved quantum mechanical models were implemented using an effective Hamiltonian in the form of irreducible tensors. The global modeling permitted more extensive quantum assignments to be made for transitions arising from both from the ground state and the two lowest fundamentals. The standard deviations of the global fit represent significant improvement with respect to previous studies of phosphine spectroscopy at these wavelengths. These results will be presented. Part of the research described in this paper was performed at the Jet Propulsion Laboratory, California Institute of Technology, under contract with The National Aeronautics and Space Administration. I.K. also thanks the Programme National de Planétologie for funding part of this research.

Brown, Linda R.; Nikitin, A.; Champion, J.; Kleiner, I.; Butler, R. A. H.

2008-09-01

161

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

PubMed Central

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

2012-01-01

162

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

163

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

164

C?C coupling of ketones with methanol catalyzed by a N-heterocyclic carbene-phosphine iridium complex.  

PubMed

An N-heterocyclic carbene-phosphine iridium complex system was found to be a very efficient catalyst for the methylation of ketone via a hydrogen transfer reaction. Mild conditions together with low catalyst loading (1?mol?%) were used for a tandem process which involves the dehydrogenation of methanol, C?C bond formation with a ketone, and hydrogenation of the new generated double bond by iridium hydride to give the alkylated product. Using this iridium catalyst system, a number of branched ketones were synthesized with good to excellent conversions and yields. PMID:25589169

Quan, Xu; Kerdphon, Sutthichat; Andersson, Pher G

2015-02-23

165

Phosphinate chemistry in the 21st century: a viable alternative to the use of phosphorus trichloride in organophosphorus synthesis.  

PubMed

Organophosphorus compounds are important in everyday applications ranging from agriculture to medicine and are used in flame retardants and other materials. Although organophosphorus chemistry is known as a mature and specialized area, researchers would like to develop new methods for synthesizing organophosphorus compounds to improve the safety and sustainability of these chemical processes. The vast majority of compounds that contain a phosphorus-carbon bond are manufactured using phosphorus trichloride (PCl3) as an intermediate. However, these reactions require chlorine, and researchers would like to avoid the use of PCl3 and develop safer chemistry that also decreases energy consumption and minimizes waste. Researchers have already proposed and discussed two primary strategies based on elemental phosphorus (P4 or Pred) or on phosphine (PH3) as alternatives to PCl3. However, phosphinates, an important class of phosphorus compounds defined as any compound with a phosphorus atom attached to two oxygens, R(1)R(2)P(O)(OR) (R(1)/R(2) = hydrogen/carbon), offer another option. This Account discusses the previously neglected potential of these phosphinates as replacements of PCl3 for the preparation of organophosphorus compounds. Because of their strong reductive properties, industry currently uses the simplest members of this class of compounds, hypophosphites, for one major application: electroless plating. In comparison with other proposed PCl3 surrogates, hypophosphorous derivatives can offer improved stability, lower toxicity, higher solubility, and increased atom economy. When their reducing power is harnessed to form phosphorus-carbon or phosphorus-oxygen bonds, these compounds are also rich and versatile precursors to organophosphorus compounds. This Account examines the use of transition metal-catalyzed reactions such as cross-coupling and hydrophosphinylation for phosphorus-carbon bond formation. Because the most important industrial organophosphorus compounds include compounds triply or quadruply bound to oxygen, I also discuss controlled transfer hydrogenation for phosphorus-oxygen bond formation. I hope that this Account will further promote research in this novel and exciting yet much underdeveloped area of phosphinate activation. PMID:23909275

Montchamp, Jean-Luc

2014-01-21

166

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

167

Ammonia, Phosphine, And Cloud Structure On Saturn Derived From 5-micron Spectra  

NASA Astrophysics Data System (ADS)

The CSHELL spectrometer on NASA's Infrared Telescope Facility was used to observe Saturn at several settings between 5.07 and 5.27?m beginning in 2004 February through 2006 January at about the same time as Cassini/VIMS and CIRS were mapping the planet. At these wavelengths thermal radiation originates from the deep atmosphere (5 bars) and it is attenuated by two cloud layers considered to be composed of NH4SH and condensed NH3. In addition, there is a component of sunlight reflected from the upper (NH3) cloud that varies spatially on Saturn. CSHELL can spectrally resolve profiles of absorption lines of ammonia (NH3) and phosphine (PH3) on Saturn. These lines are very broad due to collisions with 3 to 5 bars of hydrogen. The Saturn spectrum exhibits several strong NH3 and PH3 lines, as well as Fraunhofer lines due to CO in the Sun. The spatial variation of this spectrum is dominated by the variable opacity of Saturn's cloud structure. Superimposed on this are smaller variations in the mixing ratios of NH3 and PH3. The abundances of these gases can be retrieved reliably in relatively cloud-free regions between 50 South and 65 South, which are analogous to Jupiter's belts and 5-micron hot spots. Elsewhere, it is more difficult to separate changes in cloud opacity from gas abundances. We use near-simultaneous CIRS observations which sound the 500-mbar level to provide an upper boundary condition to PH3. The 5-?m spectrum of Saturn's Equatorial Zone (10 South) is significantly different from a region near 60 South. The NH3 and PH3 lines are weaker and narrower in the EQZ, while the Fraunhofer lines are stronger. We will present synthetic spectra calculated from models which fit both regions and which explore the tradeoffs between gas mixing ratios and cloud opacity. This work was supported by NASA's Planetary Astronomy program.

Bjoraker, Gordon; Chanover, N.; Glenar, D.; Hewagama, T.

2006-09-01

168

Tuning the host-guest interactions in a phosphine coordination polymer through different types of post-synthetic modification.  

PubMed

The porous Phosphine Coordination Material, PCM-10 contains abundant free P(III) donor sites that can be subjected to a variety of post-synthetic modifications. The diverse P(III)/P(V) organic reactivity and coordination chemistry available to aryl phosphines have been exploited to decorate the pores of PCM-10, allowing for an extensive structure-function study. Polar P?O moieties, charged P(+)-CH3 phosphonium species with exchangeable coanions (I(-), F(-), BF4(-), and PF6(-)) and P-AuCl groups have been successfully post-synthetically incorporated. These modifications directly affect the strength of the resulting host-guest interactions, as demonstrated by comparative sorption studies of CO2, H2, and other gases in the solid-state. Broad tunability of the enthalpy of CO2 adsorption is observed: incorporation of BF4(-) ions inside the pores of PCM-10 results in 24% enhancement of the isosteric adsorption enthalpy of CO2 compared to the parent material, while F(-) anions induce a 36% reduction. Meanwhile, AuCl-decorated PCM-10 shows a high H2 sorption capacity of 4.72 wt % at 77 K and 1.0 bar, versus only 0.63 wt % in the unmodified material. PMID:24359324

Nuñez, Ana J; Chang, Maxwell S; Ibarra, Ilich A; Humphrey, Simon M

2014-01-01

169

[5,10,15,20-Tetra­kis(4-chloro­phen­yl)porphyrinato]bis­(tributyl­phosphine)cobalt(III) perchlorate  

PubMed Central

In the mol­ecule of the title compound, [Co(C44H24Cl4N4){(C4H9)3P}2]ClO4, the CoIII centre has a slightly distorted octa­hedral geometry and is coordinated by four N atoms of the tetra­pyrrolic ring in the equatorial positions and two phosphine ligands in the axial positions. The dihedral angles between meso-substituted chloro­phenyl rings and the basic tetra­pyrrolic ring are 82.66?(9), 82.16?(7), 83.97?(11) and 76.87?(8)°. In one of the phosphine ligands, the two terminal methyl groups are disordered over two positions with refined site-occupancy ratios of 0.70?(7):0.30?(7) and 0.66?(2):0.34?(2). In the crystal structure, mol­ecules are linked together along the a axis by inter­molecular C—H?Cl inter­actions. The crystal structure is further stabilized by intra­molecular C—H?O and C—H?N inter­actions and inter­molecular C—H?O and C—H?? inter­actions. PMID:21583053

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

2009-01-01

170

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

PubMed Central

In this paper we describe the phosphine-catalyzed [3 + 2], [3 + 3], [4 + 3], and [3 + 2 + 3] annulations of azomethine imines and allenoates. These processes mark the first use of azomethine imines in nucleophilic phosphine catalysis, producing dinitrogen-fused heterocycles, including tetrahydropyrazolo-pyrazolones, -pyridazinones, -diazepinones, and -diazocinones. Counting the two different reaction modes in the [3 + 3] cyclizations, there are five distinct reaction pathways—the choice of which depends on the structure and chemical properties of the allenoate. All reactions are operationally simple and proceed smoothly under mild reaction conditions, affording a broad range of 1,2-dinitrogen–containing heterocycles in moderate to excellent yields. A zwitterionic intermediate formed from a phosphine and two molecules of ethyl 2,3-butadienoate acted as a 1,5-dipole in the annulations of azomethine imines, leading to the [3 + 2 + 3] tetrahydropyrazolodiazocinone products. The incorporation of two molecules of an allenoate into an eight-membered-ring product represents a new application of this versatile class of molecules in nucleophilic phosphine catalysis. The salient features of this protocol—the facile access to a diverse range of nitrogen-containing heterocycles and the simple preparation of azomethine imine substrates—suggest that it might find extensive applications in heterocycle synthesis. PMID:21812448

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

2011-01-01

171

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

172

Solvent-Free Esterification of Carboxylic Acids and Alcohols in the Presence of Silphos [PCl3-n (SiO2)n] as a Heterogeneous Phosphine Reagent  

Microsoft Academic Search

An efficient solvent-free method for the preparation of esters from various aromatic and aliphatic acids with primary, secondary, tertiary alcohols using a Heterogeneous Phosphine Reagent, Silphos [PCl3-n(SiO2)n] in high yields is reported.

Ambati Narasimha Rao; Kumaran Ganesan; Chandra Kant Shinde

2012-01-01

173

Solvent-Free Esterification of Carboxylic Acids and Alcohols in the Presence of Silphos [PCl3-n(SiO2)n] as a Heterogeneous Phosphine Reagent  

Microsoft Academic Search

An efficient solvent-free method for the preparation of esters from various aromatic and aliphatic acids with primary, secondary, and tertiary alcohols using a heterogeneous phosphine reagent, silphos [PCl3-n(SiO2)n], in good yields is reported.

Ambati Narasimha Rao; Kumaran Ganesan; Chandra Kant Shinde

2012-01-01

174

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

175

Synthesis and reactions of cubane-type iron-sulfur-phosphine clusters, including soluble clusters of nuclearities 8 and 16.  

PubMed

A family of soluble, reduced iron-sulfur clusters with nuclearities 4, 8, and 16 having tertiary phosphine ligation and based on the Fe(4)S(4) cubane-type structural motif has been synthesized. The results of this investigation substantially extend and improve the results of our original work on iron-sulfur-phosphine clusters (Goh, C.; Segal, B. M.; Huang, J.; Long, J. R.; Holm, R. H. J. Am. Chem. Soc. 1996, 118, 11844). A general property of this cluster family is facile phosphine substitution. The clusters [Fe(4)S(4)(PR(3))(4)](+) are precursors to monosubstituted [Fe(4)S(4)(PR(3))(3)X] (X = Cl-, RS-), homoleptic [Fe(4)S(4)(SR)(4)](3-), and all-ferrous monocubanes [Fe(4)S(4)(PR(3))(4)] (R = Pr(i), Cy, Bu(t); generated in solution). In turn, [Fe(4)S(4)(PPr(i)()(3))(3)(SSiPh(3))] and [Fe(4)S(4)(PPr(i)(3))(4)] can be transformed into the dicubanes [Fe(8)S(8)(PPr(i)()(3))(4)(SSiPh(3))(2)] and [Fe(8)S(8)(PPr(i)((3))(6)], respectively. Further, the tetracubanes [Fe(16)S(16)(PR(3))(8)] are also accessible from [Fe(4)S(4)(PR(3))(4)] under different conditions. X-ray structures are described for [Fe(4)S(4)(PCy(3))(3)X] (X = Cl-, PhS-), [Fe(8)S(8)(PPr(i)(3))(4)(SSiPh(3))(2)], [Fe(8)S(8)(PPr(i)()(3))(6)], and [Fe(16)S(16)(PCy(3))(8)]. The monosubstituted clusters show different distortions of the [Fe(4)S(4)](+) cores from idealized cubic symmetry. The dicubanes possess edge-bridged double cubane structures with an Fe(2)(mu(4)-S)(2) bridge rhomb and idealized C(2)(h)() symmetry. The ready cleavage of these clusters into single cubanes is considered a probable consequence of strained bond angles at the mu(4)-S atoms. Tetracubanes contain four individual cubanes, each of which is implicated in two bridge rhombs so as to generate a cyclic structure of idealized D(4) symmetry. Redox properties and Mössbauer spectroscopic parameters are reported. The species [Fe(4)S(4)(PR(3))(4)] (in solution), [Fe(8)S(8)(PR(3))(6)], and [Fe(16)S(16)(PR(3))(8)] are the only synthetic all-ferrous clusters with tetrahedral iron sites that have been isolated. Their utility as precursors to other highly reduced iron-sulfur clusters is under investigation. PMID:12513073

Zhou, Hong-Cai; Holm, R H

2003-01-13

176

Summary of GPC/DV results for space exposed poly(arylene ether phosphine oxide)s  

NASA Technical Reports Server (NTRS)

Gel Permeation Chromatography (GPC) was used to analyze poly(arylene ether phosphine oxide)s whose backbones were identical except for the ketone content and placement. These samples were exposed to low Earth orbit environment (predominantly atomic oxygen) on space shuttle flights. The materials and their unexposed controls were then characterized by GPC to investigate the effect of atomic oxygen on the molecular weight distributions. Analysis of the soluble portion of the samples revealed that there was significant loss of high molecular weight species. The presence of insoluble material also suggested that crosslinking was induced by the atomic oxygen exposure and that this very likely occurred at the high molecular weight portion of the molecular weight distribution.

Siochi, Emilie

1995-01-01

177

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

PubMed

Reduction of disulfide bonds is - in many cases - a critical pretreatment step for the determination of thiols in real samples. This study reports the first systematic investigation of the potentials of the on-line reduction of disulfide bonds under flow conditions in a sequential injection setup. One of the most promising reducing agents, tris-(2-carboxyethyl)phosphine (TCEP) was selected for this purpose while the Ellman's disulfide (DTNB) was used as model compound. The study involved the investigation of several parameters that affected the kinetics and efficiency of the reaction, including stopped-flow experiments. Both soluble and immobilized TCEP on agarose beads were examined. The results confirmed that both forms of TCEP can be used as an advantageous on-line reducing reagent for disulfide bonds under flow conditions. PMID:22817922

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

2012-07-15

178

Crystal structure and computational investigation of an analogue of Grubbs' second generation catalyst with a fluorous phosphine.  

PubMed

A fluorous phosphine analogue of Grubbs' second generation olefin metathesis catalyst, (H(2)IMes)((R(f8)(CH(2))(2))(3)P)(Cl)(2)Ru(=CHPh) (1; H(2)IMes/R(f8) = 1,3-dimesityl-4,5-dihydroimidazol-2-ylidene/(CF(2))(7)CF(3)) is crystallized and the X-ray structure analyzed in detail. The bond lengths and angles about ruthenium are compared to those of two solvates and five derivatives of Grubbs' second generation catalyst. All exhibit distorted square pyramidal geometries in which the alkylidene ligands occupy apical positions, and geometric trends are interpreted with the help of density functional calculations. The perfluoroalkyl groups (1) exhibit helical conformations, as manifested by various torsional relationships, (2) segregate in the lattice, and (3) align in pairs of opposite helical chiralities. PMID:22954330

Tuba, Robert; Brothers, Edward N; Reibenspies, Joseph H; Bazzi, Hassan S; Gladysz, John A

2012-09-17

179

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

PubMed

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

Shacklady-McAtee, Danielle M; Roberts, Kelsey M; Basch, Corey H; Song, Ye-Geun; Watson, Mary P

2014-07-01

180

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

SciTech Connect

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

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

2006-06-01

181

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

2015-01-12

182

Phosphine-stabilised Au9 clusters interacting with titania and silica surfaces: The first evidence for the density of states signature of the support-immobilised cluster  

NASA Astrophysics Data System (ADS)

Chemically made, atomically precise phosphine-stabilized clusters Au9(PPh3)8(NO3)3 were deposited on titania and silica from solutions at various concentrations and the samples heated under vacuum to remove the ligands. Metastable induced electron spectroscopy was used to determine the density of states at the surface, and X-ray photoelectron spectroscopy for analysing the composition of the surface. It was found for the Au9 cluster deposited on titania that the ligands react with the titania substrate. Based on analysis using the singular value decomposition algorithm, the series of MIE spectra can be described as a linear combination of 3 base spectra that are assigned to the spectra of the substrate, the phosphine ligands on the substrate, and the Au clusters anchored to titania after removal of the ligands. On silica, the Au clusters show significant agglomeration after heat treatment and no interaction of the ligands with the substrate can be identified.

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

2014-07-01

183

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

Microsoft Academic Search

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

N. S. Awwad; E. H. Borai

2009-01-01

184

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

185

Synthesis of 1-[bis(trifluoromethyl)phosphine]-1'-oxazolinylferrocene ligands and their application in regio- and enantioselective Pd-catalyzed allylic alkylation of monosubstituted allyl substrates.  

PubMed

A class of novel, easily accessible and air-stable 1-[bis(trifluoromethyl)phosphine]-1'-oxazolinylferrocene ligands has been synthesized from ferrocene. It became apparent that these ligands can be used in the regio- and enantioselective Pd-catalyzed allylic alkylation of monosubstituted allyl substrates in a highly efficient manner. Excellent regio- and enantioselectivity could be obtained for a wide range of substrates. PMID:24991277

Lai, Zeng-Wei; Yang, Rong-Fei; Ye, Ke-Yin; Sun, Hongbin; You, Shu-Li

2014-01-01

186

Synthesis of 1-[bis(trifluoromethyl)phosphine]-1’-oxazolinylferrocene ligands and their application in regio- and enantioselective Pd-catalyzed allylic alkylation of monosubstituted allyl substrates  

PubMed Central

Summary A class of novel, easily accessible and air-stable 1-[bis(trifluoromethyl)phosphine]-1’-oxazolinylferrocene ligands has been synthesized from ferrocene. It became apparent that these ligands can be used in the regio- and enantioselective Pd-catalyzed allylic alkylation of monosubstituted allyl substrates in a highly efficient manner. Excellent regio- and enantioselectivity could be obtained for a wide range of substrates. PMID:24991277

Lai, Zeng-Wei; Yang, Rong-Fei; Ye, Ke-Yin

2014-01-01

187

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

PubMed Central

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

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

2012-01-01

188

Exploitation of Copper Bleed Stream for the Extraction and Recovery of Copper and Nickel by Bis(2,4,4-trimethylpentyl)phosphinic Acid  

Microsoft Academic Search

Bleed streams from copper electrolysis\\/electrowinning processes potentially contain high amounts of acid, copper, and nickel which need an effective treatment before disposal. A systematic study was carried out to optimize the parameters for the extraction and recovery of metal values using bis(2,4,4-trimethylpentyl)phosphinic acid (Cyanex 272) diluted with kerosene. Since pH has a major role to play in the separation of

Archana Agrawal; S. Kumari; M. Parveen; K. K. Sahu

2012-01-01

189

Synthesis, characterization and reactivity of polypyridyl ruthenium(II) carbonyl complexes with phosphine derivatives: Ruthenium–carbon bond labilization based on steric and electronic effects  

Microsoft Academic Search

Ruthenium phosphine complexes with a CO ligand [Ru(tpy)(PR3)(CO)Cl]+ (tpy=2,2?:6?,2?-terpyridine, R=Ph or p-tolyl), were prepared by introduction of CO gas to the corresponding dichloro complexes at room temperature. New carbonyl complexes were characterized by various methods including structural analyses. They were shown to release CO following the addition of several N-donors to form the corresponding substituted complexes. The kinetic data and

Dai Ooyama; Madoka Saito

2006-01-01

190

Phosphine, isocyanide, and alkyne reactivity at pentanuclear molybdenum/tungsten-iridium clusters.  

PubMed

The trigonal bipyramidal clusters M2Ir3(?-CO)3(CO)6(?(5)-C5H5)2(?(5)-C5Me4R) (M = Mo, R = Me , R = H; M = W, R = Me, H) reacted with isocyanides to give ligand substitution products M2Ir3(?-CO)3(CO)5(CNR')(?(5)-C5H5)2(?(5)-C5Me4R) (M = Mo, R = Me, R' = C6H3Me2-2,6 ; M = Mo, R = Me, R' = (t)Bu ), in which core geometry and metal atom locations are maintained, whereas reactions with PPh3 afforded M2Ir3(?-CO)4(CO)4(PPh3)(?(5)-C5H5)2(?(5)-C5Me4R) (M = Mo, R = Me , H ; M = W, R = Me , H), with retention of core geometry but with effective site-exchange of the precursors' apical Mo/W with an equatorial Ir. Similar treatment of trigonal bipyramidal MIr4(?-CO)3(CO)7(?(5)-C5H5)(?(5)-C5Me5) (M = Mo , W ) with PPh3 afforded the mono-substitution products MIr4(?-CO)3(CO)6(PPh3)(?(5)-C5H5)(?(5)-C5Me5) (M = Mo ; M = W ), and further reaction of the molybdenum example with excess PPh3 afforded the bis-substituted cluster MoIr4(?3-CO)2(?-CO)2(CO)4(PPh3)2(?(5)-C5H5)(?(5)-C5Me5) (). Reaction of with diphenylacetylene proceeded with alkyne coordination and C[triple bond, length as m-dash]C cleavage, affording Mo2Ir3(?4-?(2)-PhC2Ph)(?3-CPh)2(CO)4(?(5)-C5H5)2(?(5)-C5Me5) () together with an isomer. Reactions of and with PhC[triple bond, length as m-dash]CR afforded MIr4(?3-?(2)-PhC2R)(?3-CO)2(CO)6(?(5)-C5H5)(?(5)-C5Me5) (M = Mo, R = Ph ; M = W, R = Ph , H; M = W, R = C6H4(C2Ph)-3 , C6H4(C2Ph)-4), while addition of 0.5 equivalents of the diynes 1,3-C6H4(C2Ph)2 and 1,4-C6H4(C2Ph)2 to WIr4(?-CO)3(CO)7(?(5)-C5H5)(?(5)-C5Me5) gave the linked clusters [WIr4(CO)8(?(5)-C5H5)(?(5)-C5Me5)]2(?6-?(4)-PhC2C6H4(C2Ph)-X) (X = 3, 4). The structures of , , , , , , and were determined by single-crystal X-ray diffraction studies, establishing the core isomerization of , the site selectivity for ligand substitution in , the alkyne C[triple bond, length as m-dash]C dismutation in , and the site of alkyne coordination in . For clusters , ease of oxidation increases on increasing donor strength of ligand, increasing extent of ligand substitution, replacing Mo by W, and decreasing core Ir content, the Ir-rich clusters and being the most reversible. For clusters , ease of oxidation diminishes on replacing Mo by W, increasing the Ir content, and proceeding from mono-yne to diyne, although the latter two changes are small. In situ UV-vis-near-IR spectroelectrochemical studies of the (electrochemically reversible) reduction process of were undertaken, the spectra becoming increasingly broad and featureless following reduction. The incorporation of isocyanides, phosphines, or alkyne residues in these pentanuclear clusters all result in an increased ease of oxidation and decreased ease of reduction, and thereby tune the electron richness of the clusters. PMID:25791388

Simpson, Peter V; Randles, Michael D; Gupta, Vivek; Fu, Junhong; Moxey, Graeme J; Schwich, Torsten; Morshedi, Mahbod; Cifuentes, Marie P; Humphrey, Mark G

2015-04-01

191

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

PubMed

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

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

2004-05-01

192

Separation of phenols from dilute aqueous solution by use of tri-n-octyl phosphine oxide as extractant  

SciTech Connect

Trioctyl phosphine oxide (TOPO) is examined as an extractant for phenol and other phenolic compounds. Equilibrium distribution coefficients have been measured for extraction of phenol, dihydroxybenzenes, and trihydroxybenzenes by solvents composed of TOPO in various diluents. Results are interpreted in terms of a model based upon complexation stoichiometry, allowing for solvation of uncomplexed solute as well. TOPO is a strong complexant for all the phenolic solutes studied. The nature of the diluent has a significant effect upon distribution coefficients, and in the case of an alcohol diluent reduces the distribution coefficient for phenol considerably. The degree of complexation remains appreciable at temperatures which would be used for regeneration of phenol by distillation. This makes it necessary to use a diluent boiling at least 70/sup 0/C to 80/sup 0/C higher than the boiling point of phenol, which is 182/sup 0/C. Regeneration studies are reported for isobutyl heptyl ketone, dimethylnaphthalene, and a mixture of dimethylnaphthlene and n-octadecane as diluents. Extraction with TOPO will be most worthy of consideration for feed concentrations of phenol equal to 3000 ppM or less, or for extraction of di- and tri-hydroxybenzenes.

MacGlashan, J.D.; Bixby, J.L.; King, C.J.

1985-01-01

193

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

194

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

SciTech Connect

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

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

2010-01-12

195

Part I. Synthesis, characterization, and reactivity of novel rhenium (V) phosphine complexes. Part II. Efficacy of computer-assisted labs  

NASA Astrophysics Data System (ADS)

Part I describes the synthesis of the fac-cis and mer-trans isomers of ReOCl3(PEt3) 2 in high yield with the fac-cis isomer being structurally characterized by X-ray crystallography for the first time. The heptahydrides ReH7(PR3)2 and pentahydrides ReH5(PR 3)3 have been synthesized where R = Me, Et. The previously unreported compounds ReO(OR)Cl2(PMe3)2 and ReO(OR)Cl2(PEt3)2, where R = Me, Et, have been synthesized through phosphine displacement on the complex ReO(OR)Cl 2(PPh3)2, with the methyl derivative being characterized by X-ray crystallography. Part II describes two new electrochemistry experiments which utilize computers to collect and organize data. The first involves solution conductivity and incorporates a titration of an acid mixture with a strong base. The second involves a titration using a student-built ion sensitive electrode. Student conceptual knowledge was assessed both before and after the experiments were implemented by semi-structured interviews. A quasi-control group was also interviewed. Electrochemical misconceptions are identified, analyzed and discussed. Teaching strategies and recommendations are given.

Smith, Kimberly Jo

2000-12-01

196

Clay intercalation catalysts interlayered with rhodium phosphine complexes. Surface effects on the hydrogenation and isomerization of 1-hexene  

SciTech Connect

Clay intercalation catalysts formed by interlayering of Na/sup +/-hectorite with rhodium phosphine complexes of the type Rh(NBD)(PPh/sub 3/)/sub 2//sup +/ and Rh(NBD)(dppe)/sup +/, where NBD = norbornadiene and dppe = 1,2-bis(diphenylphosphino)ethane, were examined as catalyst precursors for the hydrogenation-isomerization of 1-hexene in methanol. Relative to reaction under homogeneous solution conditions, the intercalated catalysts exhibit a much lower tendency to isomerize the substrate to the less reactive internal olefin 2-hexene. In the case of Rh(NBD)(PPh/sub 3/)/sub 2//sup +/-hectorite, the dramatic dependence of the hexane: 2-hexene product ratio on substrate concentration and water content indicates that the intrinsic Bronsted acidity of partially hydrated Na/sup +/ ions in the clay interlayers causes the protonic equilibrium between surface intermediates responsible for the isomerization and hydrogenation pathways to be shifted in favvor of hydrogenation. Rh(NBD)(dppe)/sup +/-hectorite also favors hydrogenation over isomerization relative to homogeneous solution. In this case, however, a catalytically important protonic equilibrium is not involved in the reaction mechanism, and the reaction is insensitive to factors which influence surface acidity. The results demonstrate that surface chemical effects can dramatically alter the catalytic properties of metal complexes immobilized in clay interlayers.

Raythatha, R.; Pinnavaia, T.J.

1983-03-01

197

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

198

Chiral Induction in the synthesis of 4,4-dimethyl-1-phenylpenta-1,2-diene (1Ph3-t-Bu-allene) catalyzed by chiral phosphine complexes of palladium  

Microsoft Academic Search

4, 4-Dimethyl-1-phenylpenta-1,2-diene (1-phenyl-3-t-butylallene) (2) has been prepared by a palladium-catalyzed cross-coupling reaction between either in situ prepared 4,4-dimethylpenta-1,2-dienylzinc chloride and iodobenzene (Route A) or 1-bromo-4,4-dimethylpenta-1,2-diene and phenylzinc chloride (Route B). Several palladium complexes with known chiral phosphine, phosphine-amine and diphosphine ligands were used as chiral catalysts. The highest enantiomeric excess (25% ee) was obtained via route A with catalysis by

G. van Koten; W. de Graaf; J. Boersma; C. J. Elsevier

1989-01-01

199

Allylation of Phosphorus, Arsenic, and Antimony Trihalides by Allylic Stannanes. Synthesis, Spectroscopic Characterization, and Quantum Chemical Investigations of Allylic Phosphines, Arsines, and Stibines.  

PubMed

The reaction between an allylic tributylstannane and a phosphorus, arsenic, or antimony trihalide led to the corresponding allylic phosphine, arsine, or stibine dihalides. With phosphorus derivatives, only the gamma-regioselection was observed, as shown by the formation of (1-methyl-2-propenyl)- (2e,f)or (1,1-dimethyl-2-propenyl)dihalophosphines (2g,h) starting from crotylstannanes 1c,c' or prenylstannane 1d, respectively, and PCl(3) or PBr(3). On heating at 80 degrees C, some of these phosphines led to the corresponding thermodynamic products. Allylic dichloroarsines 3a-d were also prepared and kinetic compounds 3c,d completely rearranged at room temperature into the corresponding crotyl- (3e,e') and prenyldichloroarsines (3f). For antimony derivatives, even at low temperature (-90 degrees C), crude mixtures containing only the thermodynamic products were observed. While allylic dihalophosphines and -arsines are not efficient allylation reagents of electrophiles, allylic dichlorostibines 4a,c reacted with benzaldehyde to lead to the corresponding homoallyl alcohols. Syn and anti products were mainly produced starting from crotyldichlorostibines (4e,e'). The primary allylic phosphines 7a-f, arsines 8a-f, and stibines 9a,bhave been prepared by the chemoselective reduction of the corresponding allylic dihalophosphines, -arsines, or -stibines with LAH in tetraglyme or with Bu(3)SnH as reducing agent and characterized by (1)H and (13)C NMR spectroscopy and mass spectrometry. The primary allylic arsines and stibines are the first elements of new classes of compounds. Several allylic phosphines and arsines were investigated by ab initio quantum chemical methods and photoelectron spectroscopy. The most stable structure of these compounds is when the C-E (E = P, As) bond is out of the plane of the allyl system. This conformation is stabilized by the hyperconjugation between the pi-orbital and the C-E sigma-bond. Due to this geometrical arrangement, the phosphorus (arsenic) lone pair interacts strongly and unprecedently with the pi-system. The strength of this interaction is due to the close proximity of the pi and the n(P) (n(As)) levels. PMID:11674043

Le Serre, Stéphanie; Guillemin, Jean-Claude; Karpati, Tamás; Soos, László; Nyulászi, László; Veszprémi, Tamás

1998-01-01

200

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

201

Structure and Reactivity of [(L•Pd)n•(1,5-cyclooctadiene)] (n=1-2) Complexes Bearing Biaryl Phosphine Ligands.  

PubMed

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

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

2014-10-01

202

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

203

Air-stable gold nanoparticles ligated by secondary phosphine oxides for the chemoselective hydrogenation of aldehydes: crucial role of the ligand.  

PubMed

The synthesis of air-stable and homogeneous gold nanoparticles (AuNPs) employing tert-butyl(naphthalen-1-yl)phosphine oxide as supporting ligand is described via NaBH4 reduction of a Au(I) precursor, [(tert-butyl(naphthalen-1-yl)phosphine oxide)AuCl]2. This highly reproducible and simple procedure furnishes small (1.24 ± 0.16 nm), highly soluble nanoparticles that are found to be highly active catalysts for the hydrogenation of substituted aldehydes, giving high conversions and chemoselectivities for a wide variety of substrates. In addition to catalytic studies the role of the novel stabilizer in the remarkable activity and selectivity exhibited by this system was interrogated thoroughly using a wide range of techniques, including ATR FT-IR, HRMAS NMR, XPS, and EDX spectroscopy. In particular, isotopic labeling experiments enabled us to probe the coordination mode adopted by the SPO ligand bound to the nanoparticle surface by ATR FT-IR spectroscopy. In combination with a series of control experiments we speculate that the SPO ligand demonstrates ligand-metal cooperative effects and plays a seminal role in the heterolytic hydrogenation mechanism. PMID:24444462

Cano, Israel; Chapman, Andrew M; Urakawa, Atsushi; van Leeuwen, Piet W N M

2014-02-12

204

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

205

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

206

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

207

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

PubMed

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

Vassiliou, Stamatia; W?glarz-Tomczak, Ewelina; Berlicki, ?ukasz; Pawe?czak, Ma?gorzata; Nocek, Bogus?aw; Mulligan, Rory; Joachimiak, Andrzej; Mucha, Artur

2014-10-01

208

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

PubMed

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

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

2013-12-15

209

Iridium(III) hydrido N-heterocyclic carbene-phosphine complexes as catalysts in magnetization transfer reactions.  

PubMed

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

Fekete, Marianna; Bayfield, Oliver W; Bayfield, Oliver; Duckett, Simon B; Hart, Sam; Mewis, Ryan E; Pridmore, Natalie; Rayner, Peter J; Whitwood, Adrian

2013-12-01

210

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

211

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

212

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

was classically regarded a class A or hard Lewis acid that binds strongly to hard Lewis bases such as nitrogen t Addition of tertiary phosphines to Th(BH4)4(Et2O)2 yields the new Lewis base adducts, Th(BH4)4(PMe3)2, Th and k3 BHÃ? 4 groups are 2.91 and 2.69 Ã?, respectively. All of the Lewis base adducts of Th(BH4

Girolami, Gregory S.

213

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

PubMed

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

Warad, Ismail

2010-07-01

214

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

PubMed

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

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

2014-03-18

215

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

PubMed

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

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

2011-10-21

216

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

217

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

218

Tris(3-hydroxypropyl)phosphine is superior to dithiothreitol for in vitro assessment of vitamin K 2,3-epoxide reductase activity.  

PubMed

Use of the reductant dithiothreitol (DTT) as a substrate for measuring vitamin K 2,3-epoxide reductase (VKOR) activity in vitro has been reported to be problematic because it enables side reactions involving the vitamin K1 2,3-epoxide (K1>O) substrate. Here we characterize specific problems when using DTT and show that tris(3-hydroxypropyl)phosphine (THPP) is a reliable alternative to DTT for in vitro assessment of VKOR enzymatic activity. In addition, the pH buffering compound imidazole was found to be problematic in enhancing DTT-dependent non-enzymatic side reactions. Using THPP and phosphate-based pH buffering, we measured apparent Michaelis-Menten constants of 1.20?M for K1>O and 260?M for the active neutral form of THPP. The Km value for K1>O is in agreement with the value that we previously obtained using DTT (1.24?M). Using THPP, we successfully eliminated non-enzymatic production of 3-hydroxyvitamin K1 and its previously reported base-catalyzed conversion to K1, both of which were shown to occur when DTT and imidazole are used as the reductant and pH buffer, respectively, in the in vitro VKOR assay. Accordingly, substitution of THPP for DTT in the in vitro VKOR assay will ensure more accurate enzymatic measurements and assessment of warfarin and other 4-hydroxycoumarin inhibition constants. PMID:25524619

Krettler, Christoph; Bevans, Carville G; Reinhart, Christoph; Watzka, Matthias; Oldenburg, Johannes

2015-04-01

219

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

220

Exponential sum absorption coefficients of phosphine from 2750 to 3550 cm-1 for application to radiative transfer analyses on Jupiter and Saturn  

NASA Astrophysics Data System (ADS)

PH3 exponential sum k coefficients were computed between 2750 and 3550 cm-1 (2.82-3.64 ?m), in view of future application to radiative transfer analyses of Jupiter and Saturn in a phosphine absorption band near 3 ?m. The temperature and pressure of this data set cover the ranges from 80 to 350 K and from 10-3 to 101 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.

2006-12-01

221

How to insulate a reactive site from a perfluoroalkyl group: photoelectron spectroscopy, calorimetric, and computational studies of long-range electronic effects in fluorous phosphines P((CH(2))(m)(CF(2))(7)CF(3))(3).  

PubMed

This study advances strategy and design in catalysts and reagents for fluorous and supercritical CO(2) chemistry by defining the structural requirements for insulating a typical active site from a perfluoroalkyl segment. The vertical ionization potentials of the phosphines P((CH(2))(m)R(f8))(3) (m = 2 (2) to 5 (5)) are measured by photoelectron spectroscopy, and the enthalpies of protonation by calorimetry (CF(3)SO(3)H, CF(3)C(6)H(5)). They undergo progressively more facile (energetically) ionization and protonation (P(CH(2)CH(3))(3) > 5 > 4 approximately equal to P(CH(3))(3) > 3 > 2), as expected from inductive effects. Equilibrations of trans-Rh(CO)(Cl)(L)(2) complexes (L = 2, 3) establish analogous Lewis basicities. Density functional theory is used to calculate the structures, energies, ionization potentials, and gas-phase proton affinities (PA) of the model phosphines P((CH(2))(m)()CF(3))(3) (2'-9'). The ionization potentials of 2'-5' are in good agreement with those of 2-5, and together with PA values and analyses of homodesmotic relationships are used to address the title question. Between 8 and 10 methylene groups are needed to effectively insulate a perfluoroalkyl segment from a phosphorus lone pair, depending upon the criterion employed. Computations also show that the first carbon of a perfluoroalkyl segment exhibits a much greater inductive effect than the second, and that ionization potentials of nonfluorinated phosphines P((CH(2))(m)CH(3))(3) reach a limit at approximately nine carbons (m = 8). PMID:11841323

Jiao, Haijun; Le Stang, Sylvie; Soós, Tibor; Meier, Ralf; Kowski, Klaus; Rademacher, Paul; Jafarpour, Laleh; Hamard, Jean-Benoit; Nolan, Steven P; Gladysz, J A

2002-02-20

222

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

223

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

224

Gas phase ion chemistry and ab initio theoretical study of phosphine. III. Reactions of PH2+ and PH3+ with PH3  

NASA Astrophysics Data System (ADS)

The gas phase ion chemistry of phosphine has been investigated by ab initio theoretical calculations and experimental techniques. Following previous studies dealing with 3P+ and PH+ reacting with PH3, the quantum chemical study of these processes has been extended to the ion/molecule reactions starting from PH2+ and PH3 (reaction a) or PH3+ and PH3 (reaction b), as observed by ion trapping. In these experiments, PH2+ reacts to give P2Hn+ (n=1,3) product ions, with loss of H2 through different pathways. These processes take place at quite different rates, their constants being 2.6 and 7.6×10-10 cm3 molecule-1 s-1, respectively. The geometrical structures and energies of transition structures, reaction intermediates, and final products have been determined by ab initio theoretical methods. The initial step of the reaction of PH2+ with PH3 is formation of the H2P-PH3+ adduct. Then, a hydrogen molecule can be directly lost either from tricoordinated or tetracoordinated phosphorus, to give P-PH3+ or HP=PH2+, respectively. The shift of one H atom in HP=PH2+ produces the bridged HP(H)PH+ ion, from which further dissociation of H2 yields PPH+. The initial step of the reaction of PH3+ with PH3 is formation of the H3P-PH3+ adduct. Then inversion of the H atoms in the PH3 group transforms the adduct in an electrostatic complex. This last species is related by a dissociation process to the PH2 and PH4+ products. The heats of formation of the P2Hn+ (n=1-6) ionic species have been computed and compared with the experimental data in the literature.

Antoniotti, Paola; Operti, Lorenza; Rabezzana, Roberto; Tonachini, Glauco; Vaglio, Gian Angelo

2000-01-01

225

Water-soluble organometallic compounds. 3. Kinetic investigations of dissociative phosphine substitution processes involving water-soluble group 6 metal derivatives in miscible aqueous/organic media  

SciTech Connect

Mechanistic aspects of ligand substitution reactions of group 6 metal carbonyl derivatives containing the trisulfonated phosphine P(m-C[sub 6]H[sub 4]SO[sub 3]Na)[sub 3] (hereafter referred to as TPPTS) in pure water and water/THF media have been investigated by examination of the reactions of these derivatives with carbon monoxide as an incoming ligand. The reactions, which were carried out under 500 psi of CO in the temperature range 110-160[degrees]C, were monitored in situ by infrared spectroscopy employing a cylindrical internal reflectance reactor. Kinetic measurements show the reactions are first-order in metal complex concentration and independent of CO pressure at high CO pressures, and the rates are retarded by added TPPTS. The activation parameters for TPPTS dissociation from M(CO)[sub 5]TPPTS derivatives (M = Mo, W), e.g., in 1:1 THF/H[sub 2]O, [Delta]H[double dagger] = 28.8 [plus minus] 1.4 kcal/mol and [Delta]S[double dagger] = [minus]4.2 [plus minus] 3.5 eu and [Delta]H[double dagger] = 31.8 [plus minus] 1.5 kcal/mol and [Delta]S[double dagger] = [minus]0.73 [plus minus] 3.6 eu, respectively were shown to be quite similar to those determined for the analogous processes involving the nonsulfonated PPh[sub 3] ligand in the same solvent systems. In addition only small solvent effects were noted in going from aqueous to organic solvents for these dissociative processes. For the cis-Mo(CO)[sub 4][TPPTS][sub 2] derivative, in which the sodium ions are encapsulated by a cryptand, kryptofix-221, a steric acceleration of TPPTS dissociation is noted relative to its PPh[sub 3] analog. 27 refs., 5 figs., 6 tabs.

Darensbourg, D.J.; Bischoff, C.J. (Texas A M Univ., College Station (United States))

1993-01-06

226

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

SciTech Connect

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

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

2014-07-07

227

Bis[2-(3-carboxyphenoxy)carbonylethyl]phosphinic acid (m-BCCEP): a novel affinity cross-linking reagent for the beta-cleft modification of human hemoglobin.  

PubMed

The design and synthesis of bis[2-(3-carboxyphenoxy)carbonylethyl]phosphinic acid (m-BCCEP, 1) as a site-directed affinity reagent for cross-linking human hemoglobin have been reported as part of our long-term goal to generate artificial blood for emergency transfusions. Molecular modeling techniques were used to design the reagent, employing crystal coordinates of human hemoglobin A(0) imported from the Protein Data Bank. It was synthesized in four steps commencing from 3-hydroxybenzoic acid. The reagent 1 was converted to its trisodium salt to allow effective cross-linking in an aqueous medium. The reagent 1, as its trisodium salt, was found to specifically cross-link stroma-free human hemoglobin A(0) in the beta-cleft under oxygenated reaction conditions at neutral pH. The SDS-PAGE analyses of the modified hemoglobin pointed to the molecular mass range of 32 kDa as anticipated. The HPLC analyses of the product suggested that the cross-link had formed between the beta(1)-beta(2) subunits. Molecular dynamics simulation studies on the reagent-HbA(0) complex suggested that the predominant amino acid residues involved in the cross-linking are N-terminus Val-1 or Lys-82 on one of the beta-subunits and Lys-144 on the other. These predictions were borne out by MALDI-TOF MS analyses data of the peptide fragments obtained from tryptic digestion of the cross-linked product. The data also suggested the presence of a minor cross-link between Val-1 and Lys-82 on the opposing subunits. The oxygen equilibrium measurements of the m-BCCEP-modified hemoglobin product at 37 degrees C showed oxygen affinity (P(50) = 25.8 Torr) comparable to that of the natural whole blood (P(50) = 27.0 Torr) and significantly lower than that of stroma-free hemoglobin (P(50) = 14.19 Torr) assayed under identical conditions. The measured Hill coefficient value of 1.91 of the m-BCCEP-modified Hb product points to the reasonable retainment of oxygen-binding cooperativity after the cross-link formation. PMID:20715854

Cai, Hongyi; Roach, Timothy A; Dabek, Margaret; Somerville, Karla S; Acharya, Seetharama; Hosmane, Ramachandra S

2010-08-18

228

Identification and Characterization of Mechanism of Action of P61-E7, a Novel Phosphine Catalysis-Based Inhibitor of Geranylgeranyltransferase-I  

PubMed Central

Small molecule inhibitors of protein geranylgeranyltransferase-I (GGTase-I) provide a promising type of anticancer drugs. Here, we first report the identification of a novel tetrahydropyridine scaffold compound, P61-E7, and define effects of this compound on pancreatic cancer cells. P61-E7 was identified from a library of allenoate-derived compounds made through phosphine-catalyzed annulation reactions. P61-E7 inhibits protein geranylgeranylation and blocks membrane association of geranylgeranylated proteins. P61-E7 is effective at inhibiting both cell proliferation and cell cycle progression, and it induces high p21CIP1/WAF1 level in human cancer cells. P61-E7 also increases p27Kip1 protein level and inhibits phosphorylation of p27Kip1 on Thr187. We also report that P61-E7 treatment of Panc-1 cells causes cell rounding, disrupts actin cytoskeleton organization, abolishes focal adhesion assembly and inhibits anchorage independent growth. Because the cellular effects observed pointed to the involvement of RhoA, a geranylgeranylated small GTPase protein shown to influence a number of cellular processes including actin stress fiber organization, cell adhesion and cell proliferation, we have evaluated the significance of the inhibition of RhoA geranylgeranylation on the cellular effects of inhibitors of GGTase-I (GGTIs). Stable expression of farnesylated RhoA mutant (RhoA-F) results in partial resistance to the anti-proliferative effect of P61-E7 and prevents induction of p21CIP1/WAF1 and p27Kip1 by P61-E7 in Panc-1 cells. Moreover, stable expression of RhoA-F rescues Panc-1 cells from cell rounding and inhibition of focal adhesion formation caused by P61-E7. Taken together, these findings suggest that P61-E7 is a promising GGTI compound and that RhoA is an important target of P61-E7 in Panc-1 pancreatic cancer cells. PMID:22028818

Chan, Lai N.; Fiji, Hannah D. G.; Watanabe, Masaru; Kwon, Ohyun; Tamanoi, Fuyuhiko

2011-01-01

229

Synthesis and reactivity of new rhenium(I) complexes containing iminophosphorane-phosphine ligands: application to the catalytic isomerization of propargylic alcohols in ionic liquids.  

PubMed

[ReBr(CO)5] reacts with the iminophosphorane-phosphine ligands Ph2PCH2P(?NR)Ph2 (R = P(?O)(OEt)2 (1a), P(?O)(OPh)2 (1b), P(?S)(OEt)2 (1c), P(?S)(OPh)2 (1d), 4-C6F4CHO (1e), 4-C6F4CN (1f), 4-C5F4N (1g)) affording the neutral complexes [ReBr(?(2)-P,X-Ph2PCH2P{?NP(?X)(OR)2}Ph2)(CO)3] (X = O, R = Et (2a), Ph (2b); X = S, R = Et (2c), Ph (2d)) and [ReBr{?(2)-P,N-Ph2PCH2P(?NR)Ph2}(CO)3] (R = P(?O)(OEt)2 (3a), P(?O)(OPh)2 (3b), 4-C6F4CHO (3e), 4-C6F4CN (3f), 4-C5F4N (3g)). The reactivity of the cationic complex [Re(?(3)-P,N,S-Ph2PCH2P{?NP(?S)(OPh)2}Ph2)(CO)3][SbF6] (4d) has been explored allowing the synthesis of the cationic [Re(L)(?(2)-P,S-Ph2PCH2P{?NP(?S)(OPh)2}Ph2)(CO)3][SbF6] (L = acetone (5a), CH3C?N (5b), pyridine (5c), PPh3 (5d)) and the neutral [ReY(?(2)-P,S-Ph2PCH2P{?NP(?S)(OPh)2}Ph2)(CO)3] (Y = Cl (6a), I (6b), N3 (6c)) complexes. The catalytic activity of complex 4d in the regioselective isomerization of terminal propargylic alcohols HC?CCR(1)R(2)(OH) into ?,?-unsaturated aldehydes R(1)R(2)C?CHCHO or ketones R(3)R(4)C?CR(1)COMe (if R(2) = CHR(3)R(4)) under neutral conditions in ionic liquids has being studied. Isolation and X-ray characterization of the key intermediate rhenium(I) oxocyclocarbene complex [Re{?C(CH2)3O}(?(2)-P,S-Ph2PCH2P{?NP(?S)(OPh)2}Ph2)(CO)3][SbF6] (5e) seems to indicate that the catalytic reaction proceeds through tautomerization of the terminal alkynols to yield vinilydene-type species. PMID:23594134

García-Álvarez, Joaquín; Díez, Josefina; Gimeno, José; Seifried, Christine M; Vidal, Cristian

2013-05-01

230

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

PubMed

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

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

2011-10-01

231

Metal- and ligand-assisted CO2 insertion into Ru-C, Ru-N, and Ru-O bonds of ruthenium(II) phosphine complexes: a density functional theory study.  

PubMed

The CO2 insertion reactions of [L4Ru(?(2)-CH2C6H4)] (1), [L4Ru(?(2)-OC6H3Me)] (2), and [L4Ru(?(2)-NHC6H4)] (3), where L = PH3 and PMe3, are modeled using density functional theory methods. In 1 and 2, the metal-assisted CO2 insertion occurs because of the favorable initial axial phosphine dissociation mechanism, whereas in 3, the ligand (NHC6H4)-assisted mechanism operates (?G(?) = +19.0 kcal/mol), wherein the nucleophilic affinity of the -NHC6H4 moiety aids the CO2 insertion process. The modeled mechanisms are consistent with the experimental findings by Hartwig et al. (J. Am. Chem. Soc, 1991, 113, 6499), in which the rate of the reactions of 1 and 2 depends on the added phosphine concentration, whereas the rate of the reaction of 3 is independent of the added phosphine concentration. In 1 and 2, CO2 is preferably inserted into the Ru-Caryl bond rather than the competitive Ru-CH2 and Ru-O bonds, respectively. In 1, the ?-type orbital interaction of the aryl ring with the metal center is found to stabilize the transition state for Ru-Caryl bond insertion (?G(?) = +25.7 kcal/mol). In 2, the Ru-Caryl insertion (?G(?) = +23.0 kcal/mol) is thermodynamically preferred, while the kinetically preferred Ru-O bond insertion (?G(?) = +17.4 kcal/mol) is highly reversible. The more electron-donating and sterically bulky PMe3 facilitates the CO2 insertion of 1 and 2 because the initial dissociation of axial PMe3 is easier than that of PH3 by ca. +11.0 kcal/mol, whereas in the case of 3, the effect of PMe3 slightly increases the ?G(?) value of 3. The increase in the nucleophilic affinity of amido nitrogen in 3 and the increase in the polarity of the solvent decrease the ?G(?) value of 3 by 48%. The inclusion of the chelating dimethylphosphinoethane ligand in 3 along with the electron-donating substituent at the -NHC6H4 moiety and the polar solvent further reduces the ?G(?) value of 3 by 62%, which demonstrates the role of the chelating ligand, electron-donating substituent, and polar solvent in the ligand-assisted CO2 insertion reactions. PMID:25532614

Vadivelu, Prabha; Suresh, Cherumuttathu H

2015-01-20

232

Pincer phosphine complexes of ruthenium: formation of Ru(P-O-P)(PPh3)HCl (P-O-P = xantphos, DPEphos, (Ph2PCH2CH2)2O) and Ru(dppf)(PPh3)HCl and characterization of cationic dioxygen, dihydrogen, dinitrogen, and arene coordinated phosphine products.  

PubMed

Treatment of Ru(PPh(3))(3)HCl with the pincer phosphines 9,9-dimethyl-4,5-bis(diphenylphosphino)xanthene (xantphos), bis(2-diphenylphosphinophenyl)ether (DPEphos), or (Ph(2)PCH(2)CH(2))(2)O affords Ru(P-O-P)(PPh(3))HCl (xantphos, 1a; DPEphos, 1b; (Ph(2)PCH(2)CH(2))(2)O, 1c). The X-ray crystal structures of 1a-c show that all three P-O-P ligands coordinate in a tridentate manner through phosphorus and oxygen. Abstraction of the chloride ligand from 1a-c by NaBAr(4)(F) (BAr(4)(F) = B(3,5-C(6)H(3)(CF(3))(2))(4)) gives the cationic aqua complexes [Ru(P-O-P)(PPh(3))(H(2)O)H]BAr(4)(F) (3a-c). Removal of chloride from 1a by AgOTf yields Ru(xantphos)(PPh(3))H(OTf) (2a), which reacts with water to form [Ru(xantphos)(PPh(3))(H(2)O)H](OTf). The aqua complexes 3a-b react with O(2) to generate [Ru(xantphos)(PPh(3))(eta(2)-O(2))H]BAr(4)(F) (5a) and [Ru(DPEphos)(PPh(3))(eta(2)-O(2))H]BAr(4)(F) (5b). Addition of H(2) or N(2) to 3a-c yields the thermally unstable dihydrogen and dinitrogen species [Ru(P-O-P)(PPh(3))(eta(2)-H(2))H]BAr(4)(F) (6a-c) and [Ru(P-O-P)(PPh(3))(N(2))H]BAr(4)(F) (7a-c), which have been characterized by multinuclear NMR spectroscopy at low temperature. Ru(PPh(3))(3)HCl reacts with 1,1'-bis(diphenylphosphino)ferrocene (dppf) to give the 16-electron complex Ru(dppf)(PPh(3))HCl (1d), which upon treatment with NaBAr(4)(F), affords [Ru(dppf){(eta(6)-C(6)H(5))PPh(2)}H]BAr(4)(F) (8), in which the PPh(3) ligand binds eta(6) through one of the PPh(3) phenyl rings. Reaction of 8 with CO or PMe(3) at elevated temperatures yields the 18-electron products [Ru(dppf)(PPh(3))(CO)(2)H]BAr(F)(4) (9) and [Ru(PMe(3))(5)H]BAr(4)(F) (10). PMID:20575584

Ledger, Araminta E W; Moreno, Aitor; Ellul, Charles E; Mahon, Mary F; Pregosin, Paul S; Whittlesey, Michael K; Williams, Jonathan M J

2010-08-16

233

Aqueous Solution Chemistry of the Mo(3)PdS(4) Cube: Substitution Reactions and the Double to Single Cube Interconversion Induced by CO, Two Phosphines, Cl(-), Br(-), and NCS(-).  

PubMed

The kinetics of conversion of an edge-linked double cube, in this case [{Mo(3)PdS(4)(H(2)O)(9)}(2)](8+), to the corresponding single cube [Mo(3)(PdX)S(4)(H(2)O)(9)](4+), has been studied for the first time. Reaction is induced by six reagents X = CO, two water-soluble phosphines, Cl(-), Br(-), and NCS(-), which complex at the tetrahedral Pd. The first stage of reaction is fast and is accompanied by color changes, e.g. purple to dark blue in the case of Cl(-), assigned as double to single cube conversion. With X = CO and the two phosphines, when absorbance changes are intense enough for stopped-flow monitoring with reactants at Pd-SCN. On removal of e.g. Cl(-) by chromatography or addition of Ag(+), the double cube re-forms. PMID:11666742

Saysell, David M.; Lamprecht, Gert J.; Darkwa, James; Sykes, A. Geoffrey

1996-09-11

234

Diphenyl(1-naphthyl)phosphine ancillary for assembling of red and orange-emitting Ir(III) based phosphors; strategic synthesis, photophysics, and organic light-emitting diode fabrication.  

PubMed

Treatment of a series of dinuclear Ir(III) complexes [(fnazo)(2)Ir(?-Cl](2), [(fpiq)(2)Ir(?-Cl](2), and [(fppy)(2)Ir(?-Cl](2) with diphenyl(1-naphthyl)phosphine (dpnH) in decalin at 100 °C afforded the simple adducts, trans-N,N'-[(fnazo)(2)Ir(dpnH)Cl] (1a), trans-N,N'-[(fpiq)(2)Ir(dpnH)Cl] (1b), and trans-N,N'-[(fppy)(2)Ir(dpnH)Cl] (1c), for which the C(?)N cyclometalating reagents, that is, fnazoH, fpiqH and fppyH, stands for 4-(4-fluorophenyl)quinazoline, 1-(4-fluorophenyl)isoquinoline and 4-fluorophenylpyridine, respectively. Single crystal X-ray diffraction study on 1a revealed existence of two trans-N,N' cyclometalates, with both chloride and dpnH donors located at the positions opposite to the phenyl substituents. Subsequent heating of 1a-1c at higher temperature afforded the second isomer (2a-2c), showing formation of cis-N,N' orientation for the aforementioned cyclometalates. Further thermolysis of either trans or cis-Ir(III) complexes 1 or 2 in presence of sodium acetate, which serves as both activator and chloride scavenger, gave successful isolation of a mixture of two fully cyclometalated Ir(III) complexes trans-N,N'-[(C(?)N)(2)Ir(dpn)] (3a-3c) and cis-N,N'-[(C(?)N)(2)Ir(dpn)] (4a-4c). Structural and photophysical properties of complexes 3a-3c and 4a-4c were measured and compared. Time-dependent density functional theory (DFT) studies suggested that, upon changing the C(?)N cyclometalates from quinazolinyl, isoquinolinyl, and, finally, to pyridyl fragment, the lowest unoccupied molecular orbitals (LUMOs) are gradually shifted from the cyclometalating nitrogen heterocycles to the 1-naphthyl group of the phosphine chelate and, concomitantly altered the photophysical properties. An organic light-emitting diode (OLED) using orange-red phosphors 4a and 4b has been successfully fabricated. At the practical brightness of 500 cd·m(-2), decent external quantum efficiency of 10.6% and 12.5% could be reached for 4a and 4b, respectively, revealing the usefulness of relevant molecular architecture in designing triplet OLED emitters. PMID:20815333

Du, Bo-Sian; Lin, Chen-Huey; Chi, Yun; Hung, Jui-Yi; Chung, Min-Wen; Lin, Tsung-Yi; Lee, Gene-Hsiang; Wong, Ken-Tsung; Chou, Pi-Tai; Hung, Wen-Yi; Chiu, Hao-Chih

2010-10-01

235

Configurationally homogeneous diastereomers of a linear hexa(tertiary phosphine): Enantioselective self-assembly of a double-stranded parallel helicate of the type (P)-[Cu3(hexaphos)2](PF6)3  

PubMed Central

Three configurationally homogeneous diastereomers of the linear hexa(tertiary phosphine) Ph2PCH2CH2P(Ph)CH2CH2P(Ph)CH2CH2P(Ph)CH2CH2P(Ph)CH2CH2PPh2 (hexaphos) have been isolated in enantiomerically pure form, namely (R,S,S,R)-, (R,S,S,S)-, and (S,S,S,S)-hexaphos. The strongly helicating (R,S,S,R)-(?) form of the ligand combines with copper(I) ions to generate by stereoselective self-assembly the P enantiomer of a parallel helicate of the type [Cu3(hexaphos)2](PF6)3, which has been characterized by x-ray crystallography. Theoretical modeling of the cation indicates that it is the relationship between the helicities of the two 10-membered rings containing the three copper ions, each of which has the twist-boat–chair–boat conformation, and the configurations of the three chiral, tetrahedral copper stereocenters of P configuration that determines the stereochemistry of the parallel and double ?-helix conformers of the double-stranded trinuclear metal helicate. PMID:11929976

Bowyer, Paul K.; Cook, Vernon C.; Gharib-Naseri, Nahid; Gugger, Paul A.; Rae, A. David; Swiegers, Gerhard F.; Willis, Anthony C.; Zank, Johann; Wild, S. Bruce

2002-01-01

236

Reactions of ether-phosphine ruthenium hydride complexes with carbon disulfide and phenylacetylene: crystal structures of Ru(CO) Cl(P ? O) 3( ? 2-S 2CH and Ru(CO) Cl(P ? O) 2( ? 2-S 2CH)  

Microsoft Academic Search

The dithioformato complexes RuCl(P ? O)3(?2CH) (2ab) and RuCl(P ? O(P ? O)(?2-S2CH) (3ab) are accessible by insertion of CS2 into the Ru?H bond of the (ether-phosphine)(hydrido)ruthenium complexes RuCl(P ? O)(P ? O)2 (1a,b) [P ? O = ?1(P)-coordinated, P ? O = ?2 (O,P)-chelated; O,P = diphenyl(2-methoxyethyl)phosphone (a), (1,3-dioxan-2-methyl) diphenylphosphine (b)]. Treatment of 2a, 3a and 2b, 3b with

Ekkehard Lindner; Ying-Chih Lin; Michael Geprägs; Kuang-Hway Yih; Riad Fawzi; Manfred Steimann

1996-01-01

237

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

238

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

E-print Network

SPPLZWTIOR OF OKDKNOLZTKZKN COa OKKRS FOR TKE PREPKRATION OF KONK ALZPRSTIC AHD KLZCZCLZC PKOSPKINKS, PKOSPKZNE OXIDES QfD PKOSPRIKE SKLFI DES k Thesis Ceustautisos Seret tao subaiiteg to the Craguate Soaool a! the ~rlouitural as4 Nechauioal...OSPBINE OXIDES AND PHOSPBINE MLFIDES A Thesis Coastantinos Screttas Approve4 as te style aal coatest by& ( ha rsas o osmittee ( ea4 o Doper seat Jaasary 1961 ehe&ld 11ko te eayrees ay deey gratitade to yrefessar ii yi Kahehl ter hio valaahle 4aidaaee...

Screttas, Constantinos G

1961-01-01

239

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

SciTech Connect

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

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

1991-06-12

240

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

241

Phosphine photochemistry in the atmosphere of Saturn  

NASA Astrophysics Data System (ADS)

The photochemistry of PH3 in the atmosphere of Saturn is studied, including the effects of coupling with the photochemistries of NH3 and hydrocarbons. The vertical concentration of PH3 is found to be extremely sensitive to the eddy diffusion coefficient (K) profile used. If K is roughly 10,000 sq cm/sec in the upper troposphere, PH3 should be depleted there with a scale height of about 3.5 km. An upper limit of 100,000 sq cm/sec is estimated for K. If the gas phase concentration of P2H4 can be neglected, production of molecular phophorus is very unlikely unless the spin-forbidden recombination reaction PH+H2+M - PH3+M occurs with an exceptionally low rate. Coupling of PH3 and hydrocarbon photochemistries is very important. Possible observable amounts of the organophosphorus molecules CH3PH2 and HCP are tentatively predicted.

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

1984-09-01

242

Gold(I) derivatives of secondary phosphines  

NASA Astrophysics Data System (ADS)

A combined197Au Mössbauer and31P NMR study of the gold(I)-HPR2 system (R=phenyl, p-tolyl) has allowed the characterisation of the novel complexes [AuX(HPR2)] (X=Cl, Br) and [Au(HPR2)n]+ (n=2 4). Two forms of a polymeric phosphido-bridged compound [AuPR2]n have also been identified, only one of which has been previously reported.

Dyson, D. B.; Parish, R. V.; McAuliffe, C. A.; Fields, R.

1988-02-01

243

Phenyl bis­(m-tolyl­amido)­phosphinate  

PubMed Central

The P atom of the title compound, C20H21N2O2P, has a distorted tetra­hedral configuration; the bond angles at P are in the range 96.11?(6)–117.32?(8)°. The N atom exhibits sp 2 character. In the crystal, mol­ecules are connected via N—H?O hydrogen bonds into bands along the a axis, consisting of R 2 2(8) rings. PMID:22090923

Pourayoubi, Mehrdad; Eshtiagh-Hosseini, Hossein; Negari, Monireh; Ne?as, Marek

2011-01-01

244

Reactions of [Ru 3(CO) 10(?-Ph 2PCH 2PPh 2)] with secondary phosphines R 2Ph involving bulky substituents (R ? tBu, 1Ad, Cy); X-ray crystal structures of [Ru 3(CO) 6(?-H) 2(?-PCy 2) 2(?-Ph 2PCH 2PPh 2)] and the electron-deficient carbonyl cluster [Ru 3(?-CO)(CO) 4(? 3-H)(?-H)(?-P tBu 2) 2(?-Ph 2PCH 2PPh 2)  

Microsoft Academic Search

The reaction of [Ru3(CO)10(?-dppm)] (1) with secondary phosphines R2PH (R ? tBu, 1-Ad) in heptane under reflux leads to th electron-deficient metal cluster complexes [Ru3(?-CO)(CO)4(?3-H)(?-H)(?-PR2)2(?-dppm)] (R ? tBu 4; R ? 1-Ad 5) in good yields. The reactions yield first the monosubstituted compounds [Ru3(CO)9(R2PH)(?-dppm)] (R ? tBu, 2; R ? 1-Ad 3), which could be isolated in yields up to

H.-C. Böttcher; Holger Thönnessen; Peter G. Jones; Reinhard Schmutzler

1996-01-01

245

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

E-print Network

for the purpose of isolating tho phosphino. The entire reaction mixture may be directly subJoeted to vacuum distillation ($), or it may be first hydrelysod, either with 4iluto agueous acid or alkali. Hydrolysis is followed by separation cf tho layers... residue. This solution was then evaporated to dryness, leaving 29 g. of a red solid material which began to deoosxpose with evolution of gas at 110 . The solid o product dissolved readily in 9' ethanol but did not recrystallize. En another attempt...

Tefteller, Joseph Wilburn

1964-01-01

246

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

247

Interaction of mercury(II) halides with tertiary phosphine betaines: synthesis and structural characterization of [HgX 2 {Ph 3 P(CH 2 ) 2 CO 2 }] (X=Cl, I) and [HgCl(?-Cl)-{Ph 3 P(CH 2 ) 3 CO 2 }] 2  

Microsoft Academic Search

Three new mercury(II) complexes containing tertiary phosphine betaine ligands Ph3P+(CH2)2CO2\\u000a ? and Ph3P+(CH2)3CO2\\u000a ? have been synthesized and fully characterized by single-crystal X-ray analysis: [HgCl2{Ph3(CH2)2CO2}],1, space groupP21\\/n,a=9.819(2),b=14.966(4),c=14.973(5) Å, ?=105.67(2)° andZ=4; [HgI2{Ph3(CH2)2CO2}],2,P21\\/n,a=10.206(2),b=14.807(3),c=15.557(3) Å, ?=107.11(2)° andZ=4; [HgCl(?-Cl){Ph3P(CH2)3CO2}]2,3,\\u000a $$P\\\\bar 1$$\\u000a ,a=10.813(2),b=11.975(3),c=11.180(2) Å, ?=87.04(2), ?=75.14(1), ?=81.95(1)° andZ=1. The isomorphous complexes1 and2 contain discrete mononuclear molecules in which the mercury(II) atom is unsymmetrically chelated by

Song-Lin Li; Thomas C. W. Mak

1997-01-01

248

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

249

Hydrogen isotope exchange catalyzed by phosphine complexes of palladium  

Microsoft Academic Search

1.Bis(triphenylphosphine)bis(trifluoroacetato)palladium in aqueous solutions of trifluoroacetic acid catalyzes the isotope exchange of hydrogen between dihydrogen and the protons of the solvent.2.Hydrogen exchange proceeds through the formation and decomposition of a hydride complex of palladium, the hydrogen atom in which is capable of exchanging with the protons of the solvent.3.The introduction of ethylene into the system lowers the rate of the

V. N. Zudin; V. A. Rogov; V. A. Likholobov; V. A. Shmachkov; L. A. Sazonov; Yu. I. Ermakov

1985-01-01

250

Response of light brown apple moth to oxygenated phosphine fumigation  

Technology Transfer Automated Retrieval System (TEKTRAN)

The light brown apple moth (LBAM), Epiphyas postvittana (Walker), poses a serious threat to California agriculture and is currently quarantined by several major trading partners. Fumigation is the only tool to assure pest-free postharvest vegetable and fruit products. However, current fumigants for ...

251

Phosphine-Free EWG-Activated Ruthenium Olefin Metathesis Catalysts  

NASA Astrophysics Data System (ADS)

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

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

252

Synthesis, characterization, and reactivity of low valent technetium phosphine complexes  

E-print Network

Chapter 1. The chemistry of the metal-metal multiply bonded Tc2(II,II) core has been investigated with bis(diphenylphosphino)methane (dppm). The parent complex, Tc2Cl4(dppm)2, has been prepared from the reaction of ...

Freiberg, Evan, 1974-

2001-01-01

253

40 CFR 180.225 - Phosphine; tolerances for residues.  

Code of Federal Regulations, 2010 CFR

... Hazelnut 0.1 Kumquat 0.01 Lemon 0.01 Lettuce 0.01 Lime 0...RACs resulting from preharvest treatment of pest burrows in agricultural and non-crop...commodities resulting from preharvest treatment of pest burrows 0.01 (3) Residues...

2010-07-01

254

Phenyl bis­(morpholin-4-yl­amido)­phosphinate  

PubMed Central

In the title compound, C14H23N4O4P, the P atom is in a distorted tetra­hedral environment with bond angles in the range 96.87?(6)–119.86?(6)°. The two morpholinyl groups adopt a chair conformation. The phenyl ring is disordered over two sets of sites with equal occupancies [0.500?(2)]. In the crystal, adjacent mol­ecules are linked via N—H?O hydrogen bonds into an extended chain running parallel to the a axis. Only one of the amidate N—H groups is involved in hydrogen bonding. PMID:22091209

Pourayoubi, Mehrdad; Eshtiagh-Hosseini, Hossein; Negari, Monireh; Ne?as, Marek

2011-01-01

255

p-Tolyl bis-(o-tolyl-amido)-phosphinate.  

PubMed

In the title compound, C(21)H(23)N(2)O(2)P, the P atom has a distorted tetra-hedral configuration. The O atom of the OC(6)H(4)-4-CH(3) group and the N atoms show sp(2) character. In the crystal, adjacent mol-ecules are linked by N-H?O hydrogen bonds into helical chains parallel to the b axis. PMID:21587971

Sabbaghi, Fahimeh; Mancilla Percino, Teresa; Pourayoubi, Mehrdad; Leyva, Marco A

2010-01-01

256

p-Tolyl bis­(o-tolyl­amido)­phosphinate  

PubMed Central

In the title compound, C21H23N2O2P, the P atom has a distorted tetra­hedral configuration. The O atom of the OC6H4-4-CH3 group and the N atoms show sp 2 character. In the crystal, adjacent mol­ecules are linked by N—H?O hydrogen bonds into helical chains parallel to the b axis. PMID:21587971

Sabbaghi, Fahimeh; Mancilla Percino, Teresa; Pourayoubi, Mehrdad; Leyva, Marco A.

2010-01-01

257

rac-Phenyl (benzylamido)(p-tolyl­amido)­phosphinate  

PubMed Central

The title compound, C20H21N2O2P, was synthesized from (RS)-(C6H5O)P(O)Cl(NHC6H4-p-CH3) and benzyl­amine. The product crystallizes as a racemate in a polar space group. The phospho­rus atom has a distorted tetra­hedral configuration: the bond angles at the P atom are in the range 103.2?(1)–118.4?(1)°. The P—N(benzyl­amido) bond [1.615?(2)?Å] is slightly shorter than the P—N(p-tolyl­amido) bond [1.630?(2)?Å]. Both N—H groups adopt an anti orientation relative to the phosphoryl group. In the crystal, the adjacent mol­ecules are linked via N—H?O hydrogen bonds, forming R 2 2(8) rings, into a one-dimensional arrangement parallel to the x axis. PMID:22059060

Pourayoubi, Mehrdad; Karimi Ahmadabad, Fatemeh; Ne?as, Marek

2011-01-01

258

p-Tolyl bis­(cyclo­hexyl­amido)­phosphinate  

PubMed Central

The P atom in the title mol­ecule, C19H31N2O2P, is in a distorted tetra­hedral configuration with the bond angles in the range 101.48?(10)–118.58?(9)°. The N—H units have a syn orientation with respect to one another. In the crystal, mol­ecules are connected via two different inter­molecular N—H?O(P) hydrogen bonds into chains along the a axis in which the O atom of the P=O group acts as a double acceptor. PMID:22091179

Raissi Shabari, Akbar; Pourayoubi, Mehrdad; Taghizadeh, Afsaneh; Ghoreishi, Farnaz; Vahdani, Banafsheh

2011-01-01

259

Kinetics of substitution reactions of Fe II-phosphine complexes with Cl ?, Br ? and SCN ? in acetonitrile. A comparative study of complexes containing bidentate and tripodal phosphines  

Microsoft Academic Search

The kinetics of formation of FeLX+ complexes from FeLan22+ and X? [L ? P(CH2CH2PPh2)3, N(CH2CH2PPh2)3, (Ph2PCH2CH2PPh2)2; X ? Cl, Br, SCN; an = acetonitrile] has been studied in acetonitrile at 25.0°C and Et4NBF4 (0.05 mol dm?3). All the reactions seem to go through initial substitution of one coordinated acetonitrile by X? to form FeLX+, although in some cases the reaction

M. Angeles Máñez; M. Jesús Fernández-Trujillo; Manuel G. Basallote

1996-01-01

260

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

261

Development of a redox-free Mitsunobu reaction exploiting phosphine oxides as precursors to dioxyphosphoranes.  

PubMed

The development of the first redox-free protocol for the Mitsunobu reaction is described. This has been achieved by exploiting triphenylphosphine oxide--the unwanted by-product in the conventional Mitsunobu reaction--as the precursor to the active P(V) coupling reagent. Multinuclear NMR studies are consistent with hydroxyl activation via an alkoxyphosphonium salt. PMID:24871529

Tang, Xiaoping; Chapman, Charlotte; Whiting, Matthew; Denton, Ross

2014-07-14

262

Detection of the J-10 Manifold of the Pure Rotational Band of Phosphine on Saturn  

NASA Technical Reports Server (NTRS)

The detection of the J = 10 manifold of the pure rotational band of PH3 on Saturn is reported. The observations were made from the far-infrared cooled grating spectrometer. The wavelengths and observed brightness temperatures for the full disk plus rings are 89 + or - 3 K at 97.04 micrometer, 77 + or - 3 K at 102.72 micrometer, 77 + or - 3 K at 102.94 micrometer, and 83 + or - 3 K at 105.12 micrometers. The points of 97.04 and 105.12 micrometers establish the continuum level and the two points near 103 micrometers measure the depth of the PH3 manifold. After the flux due to the rings is subtracted, the depth of the feature is 16 + or - 6 K relative to the nearby 102 K continuum. These results are compared to theoretical models which parameterize the PH3 mixing ratio as x = x sub zero (P/P sub zero)(alpha) for P P sub zero and as x = x sub zero for P or = P, where P is the total pressure and alpha = H/h is the ratio of the dynamical scale height (H) and the scale height for decreasing the PH3 mixing ratio (h). The parameters x sub zero, P sub zero, and h were varied, as well as the H/He mixing ratio and the pressure-temperature profile. The data are well fitted using pressure-temperature profiles. The preferred values of h, P sub zero, and x sub zero imply that there is little or no PH3 above the thermal inversion and that the mixing ratio below the inversion is consistent with PH3 being 1 to 4 times overabundant relative to the solar P/H ratio.

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

1984-01-01

263

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

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

264

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

265

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

PubMed

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

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

2014-09-01

266

Bis(pyrrolidin-1-yl)phosphinic (2,4-di­fluoro­benzo­yl)amide  

PubMed Central

The P atom in the title mol­ecule, C15H20F2N3O2P, is in a distorted tetra­hedral P(O)(N)(N)2 environment. The phosphoryl group and the NH unit adopt a syn orientation with respect to each other. An F atom at position 2 and an H atom at position 6 are found to occupy similar sites in a 0.70:0.30 ratio and were refined with fixed occupancies. The pyrrolidin-1-yl rings are disordered over two sets of sites, with site occupancies of 0.566?(6) and 0.434?(6), and were refined using a two-part model. In the crystal, hydrogen-bonded dimers linked by pairs of N—H?O(P) hydrogen bonds generate an R 2 2(8) ring motif. PMID:22969580

Keikha, Mojtaba; Pourayoubi, Mehrdad; Jasinski, Jerry P.; Golen, James A.

2012-01-01

267

2-(2H-Benzotriazol-2-yl)-4-methyl­phenyl diphenyl­phosphinate  

PubMed Central

In the title mol­ecule, C25H20N3O2P, the dihedral angle between the mean planes of the benzotriazol ring system and the N-bonded benzene ring is 45.8?(2)°. All but one of the angles at the P atom show slight distortions from an ideal tetra­hedral geometry. PMID:21583720

Liu, Yi-Chang; Lin, Chia-Her; Ko, Bao-Tsan

2009-01-01

268

Chemisorption of tertiary phosphines on coinage and platinum group metal powders  

Microsoft Academic Search

The chemisorption of dimethylphenyl-, triphenyl- and tricyclohexylphosphine deposited from dilute toluene solution on the surfaces of purified gold, silver, copper, palladium, platinum and rhodium powders has been studied. The infrared spectra of the species adsorbed on the metal powder surfaces have been recorded by means of an FTIR spectrometer equipped with focusing diffuse reflectance unit optimized for specular reflectance and

Gunnar Westermark; Ingmar Persson

1998-01-01

269

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

270

Epitaxial growth of n-type SiC using phosphine and nitrogen as the precursors  

NASA Astrophysics Data System (ADS)

Epitaxial growth of n-type SiC was carried out using PH3 and N2 as the dopant precursors in a chemical vapor deposition system. Thermodynamic simulations were performed to analyze the gas phase composition at the growth conditions. It was shown that the incorporation behaviors of these two dopants are quite different. Compared to nitrogen, phosphorous incorporation has a weaker dependence on flow rate and has a limited site competition effect. Also, phosphorus incorporation for a given precursor flow decreases with temperature while that of nitrogen increases. It was also observed that phosphorous incorporation increases with decreasing C/Si when the ratio is between 0.8 and 3, which suggests phosphorous might incorporate into C site when C/Si is low. Variable temperature Hall measurements were used to characterize the doped layers. Two donor levels at 82-83 and 105-114 meV for phosphorous in 6H-SiC, 50-52 meV, and 78-80 meV for phosphorous in 4H-SiC were resolved. These results were compared to those from ion-implanted samples.

Wang, Rongjun; Bhat, Ishwara B.; Chow, T. Paul

2002-12-01

271

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

PubMed

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 (31)P NMR technique. PMID:24324893

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

2013-01-01

272

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

PubMed

A novel kind of functional organic microporous polymer is designed by introducing polar organic groups (P=O and P=S) and electron-rich heterocyclic into the framework to obtain high carbon dioxide capture capacity. The estimated Brunauer-Emmett-Teller (BET) surface areas of these polymers are about 600 m(2) g(-1) and the highest CO2 uptake is 2.26 mmol g(-1) (1.0 bar/273 K). Interestingly, the polymer containing P=O groups shows greater CO2 capture capacity than that containing P=S groups at the same temperature. In addition, these polymers show high isosteric heats of CO2 adsorption (28.6 kJ mol(-1) ), which can be competitive with some nitrogen-rich networks. Therefore, these microporous polymers are promising candidates for carbon dioxide capture. PMID:23757097

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

2013-07-25

273

rac-[2-(Dicyclohexylphosphanyl)phenyl](phenyl)phosphinic diisopropyl­amide–borane hemihydrate  

PubMed Central

In the title compound, C30H48BNOP2·0.5H2O, the water molecule is disordered about an inversion centre. Both phospho­rus atoms shows distortions in their tetra­hedral environments with the cyclo­hexyl substituents disordered over two orientations in a 0.851?(3):0.149?(3) occupancy ratio. The crystal structure is assembled via O—H?O inter­actions between pairs of phosphininc amide mol­ecules and water molecules, creating hydrogen-bonded dimers with graph-set R 2 4(8) along [001]. Weak C—H?O inter­actions are also observed. PMID:23424555

Evans, Stephen J.; Renison, C. Alicia; Williams, D. Bradley G.; Muller, Alfred

2013-01-01

274

Solar cells made by laser-induced diffusion directly from phosphine gas  

SciTech Connect

A new method for making p-n junctions based on immersion in a transparent dopant gas followed by irradiation with a pulsed laser is presented. An alexandrite laser was used, operating at 0.73 ..mu..m where photolysis of the dopant gas PH/sub 3/ does not occur. Multiple pulses of 2.2--2.7 J/cm/sup 2/ were used to make Si solar cells with total area efficiencies up to 8.6% without benefit of antireflection coatings.

Turner, G.B.; Tarrant, D.; Pollock, G.; Pressley, R.; Press, R.

1981-12-15

275

The Mechanochemical Reaction of Palladium(II) Chloride with a Bidentate Phosphine  

ERIC Educational Resources Information Center

This experiment describes the reaction of palladium(II) chloride with 1,5-bis(diphenylphosphino)pentane by grinding the two powders together in the solid state. The product is the precursor for the metalation reaction at one of the methylene carbon atoms of the ligand's backbone. The final product is known to be a catalyst for Suzuki-Miyaura…

Berry, David E.; Carrie, Philippa; Fawkes, Kelli L.; Rebner, Bruce; Xing, Yao

2010-01-01

276

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

PubMed

The synthesis and characterisation of nonclassical ruthenium hydride complexes containing bidentate PP and tridentate PCP and PNP pincer-type ligands are described. The mononuclear and dinuclear ruthenium complexes presented have been synthesised in moderate to high yields by the direct hydrogenation route (one-pot synthesis) or in a two-step procedure. In both cases [Ru(cod)(metallyl)(2)] served as a readily available precursor. The influences of the coordination geometry and the ligand framework on the structure, binding, and chemical properties of the M--H(2) fragments were studied by X-ray crystal structure analysis, spectroscopic methods, and reactivity towards N(2), D(2), and deuterated solvents. PMID:17117397

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

2007-01-01

277

1 Reactivity Differences of Pt0 Phosphine Complexes in C-C Bond  

E-print Network

Acetylenes 3 Ahmet Gunay, Christian Muller, Rene J. Lachicotte, William W. Brennessel, and 4 William D. Joneseq 1. The syntheses all involve reaction of a 1:1:1 mixture of *Corresponding author. E-mail: jones. J. Mol. Catal. A 2002, 189, 145. (6) (a) Gunay, A.; Jones, W. D. J. Am. Chem. Soc. 2007, 129, 8729

Jones, William D.

278

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

PubMed

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

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

2014-11-11

279

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

SciTech Connect

We report blue phosphorescent organic light-emitting devices (OLEDs) using an ambipolar host, N-(4-diphenylphosphoryl phenyl) carbazole (MPO12), doped with iridium (III) bis[4,6-difluorophenyl)-pyridinato-N,C2´]picolinate (FIrpic). The external quantum efficiency and operating voltage is 9.1±0.1% and 4.8 V, respectively, measured at a brightness of 800 cd/m2 with no outcoupling enhancement. By varying the layer structure of the OLEDs, we show that MPO12 is capable of transporting both electrons and holes, in contrast to previous demonstrations using diphosphine oxides, which only transported electrons. The improved hole transport results in improved device efficiency.

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

2008-02-28

280

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

SciTech Connect

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

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

1995-02-01

281

Paramagnetic effects on the NMR spectra of "diamagnetic" ruthenium(bis-phosphine)(bis-semiquinone) complexes.  

PubMed

Ligand substitution on cis-Ru(PPh(3))(2)(1,2-O(2)C(6)H(4))(2) gives cis-RuL(1)L(2)(1,2-O(2)C(6)H(4))(2) (L(1) = PPh(3), L(2) = P(OPh)(3), PBu(3); L(1) = L(2) = PBu(3), P(OMe)(3)). Syntheses of cis-Ru(PPh(3))(2)(3,4-O(2)C(6)H(2)(5-OH)CO(2)Me)(2) and cis-Ru(PPh(3))(2)(AGSQ)(2) (AGSQ = the semiquinone derived from 1,2,3-trihydroxyanthracene-9,10-dione) are also reported. The upfield chemical shifts and line broadening of the semiquinone 4,5-proton resonances in the NMR spectra indicate that these complexes, while having no detectable magnetic moments, have a weak, temperature-, ligand- and solvent-variable residual paramagnetism, not previously recognized in this series. Density functional theory (DFT) calculations predict a low-lying triplet state, about 14 kJ/mol (0.15 eV) above the singlet ground state. The paramagnetic effects on the NMR spectra are attributed to singlet-triplet equilibria. Temperature dependence of the proton resonances of the semiquinone rings of cis-Ru(PPh(3))(2)(1,2-O(2)C(6)H(4))(2) was used to calculate the singlet-triplet free energy difference as 17.5-18.0 kJ/mol in toluene. PMID:19400557

Le Guennic, Boris; Floyd, Tavon; Galan, Brandon R; Autschbach, Jochen; Keister, Jerome B

2009-06-15

282

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

E-print Network

to the dinuclear gold(I) diphenylphosphonium bismethylide complex [Au(CH ) PPh ] , 1, were studied by H NMR. Organic halides add 2 2 2 2 across the gold-gold vector of the dinuclear eight-membered ring to form M-M singly bonded gold(II) adducts in which... studied. The P NMR and H[P] NMR spectra of 2' iv 2 and 3 were examined and the reaction products of 2 and 3 were characterized by H NMR. Complex 2 may be compared to a phosphonium I salt since 2 can be deprotonated by metal hydrides to give 3, which...

Diebold, Julia Shain

1987-01-01

283

2-Isopropyl-5-methyl-cyclo-hexyl cyclo-hex-yl(phen-yl)phosphinate.  

PubMed

In the title mol-ecule, C(22)H(35)O(2)P, the two cyclo-hexyl rings exhibit chair conformations. In the crystal, mol-ecules related by translation along the b axis are linked by the weak inter-molecular C-H?O hydrogen bonds. PMID:21754248

Xu, Hao; Liu, Li-Juan; Meng, Fan-Jie; Zhao, Chang-Qiu

2011-04-01

284

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

PubMed Central

The reactions of potassium salts of the dithiocarbamates L {where L = pyrazolyldithiocarbamate (L1), 3,5-dimethylpyrazolyldithiocarbamate (L2), or indazolyldithiocarbamate (L3)} with the gold precursors [AuCl(PPh3)], [Au2Cl2(dppe)], [Au2Cl2(dppp)], or [Au2Cl2(dpph)] lead to the new gold(I) complexes [AuL(PPh3)] (1–3), [Au2L2(dppe)] (4–6), [(Au2L2)(dppp)] (7–9), and [Au2(L)2(dpph)] (10–12) {where dppe = 1,2-bis(diphenylphosphino)ethane, dppp = 1,3-bis(diphenylphosphino)propane, and dpph = 1,6-bis(diphenylphosphino)hexane}. These gold compounds were characterized by a combination of NMR and infrared spectroscopy, microanalysis, and mass spectrometry; and in selected cases by single-crystal X-ray crystallography. Compounds 4–6, which have dppe ligands, are unstable in solution for prolonged periods, with 4 readily transforming to the Au18 cluster [Au18S8(dppe)6]Cl2 (4a) in dichloromethane. Compounds 1–3 and 7–12 are all active against human cervical epithelioid carcinoma (HeLa) cells, but the most active compounds are 10 and 11, with IC50 values of 0.51 ?M and 0.14 ?M, respectively. Compounds 10 and 11 are more selective toward HeLa cells than they are toward normal cells, with selectivities of 25.0 and 70.5, respectively. Further tests, utilizing the 60-cell-line Developmental Therapeutics Program at the National Cancer Institute (U.S.A.), showed 10 and 11 to be active against nine other types of cancers. PMID:24476103

2015-01-01

285

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

PubMed

The reactions of potassium salts of the dithiocarbamates L {where L = pyrazolyldithiocarbamate (L1), 3,5-dimethylpyrazolyldithiocarbamate (L2), or indazolyldithiocarbamate (L3)} with the gold precursors [AuCl(PPh3)], [Au2Cl2(dppe)], [Au2Cl2(dppp)], or [Au2Cl2(dpph)] lead to the new gold(I) complexes [AuL(PPh3)] (1-3), [Au2L2(dppe)] (4-6), [(Au2L2)(dppp)] (7-9), and [Au2(L)2(dpph)] (10-12) {where dppe = 1,2-bis(diphenylphosphino)ethane, dppp = 1,3-bis(diphenylphosphino)propane, and dpph = 1,6-bis(diphenylphosphino)hexane}. These gold compounds were characterized by a combination of NMR and infrared spectroscopy, microanalysis, and mass spectrometry; and in selected cases by single-crystal X-ray crystallography. Compounds 4-6, which have dppe ligands, are unstable in solution for prolonged periods, with 4 readily transforming to the Au18 cluster [Au18S8(dppe)6]Cl2 (4a) in dichloromethane. Compounds 1-3 and 7-12 are all active against human cervical epithelioid carcinoma (HeLa) cells, but the most active compounds are 10 and 11, with IC50 values of 0.51 ?M and 0.14 ?M, respectively. Compounds 10 and 11 are more selective toward HeLa cells than they are toward normal cells, with selectivities of 25.0 and 70.5, respectively. Further tests, utilizing the 60-cell-line Developmental Therapeutics Program at the National Cancer Institute (U.S.A.), showed 10 and 11 to be active against nine other types of cancers. PMID:24476103

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

2014-02-17

286

Phosphonium ionic liquids based on bulky phosphines: synthesis, structure and properties.  

PubMed

A series of new ionic liquids based on sterically hindered decyl(tri-tert-butyl)phosphonium (DTBP) or decyl(tricyclohexyl)phosphonium (DCHP) cations were prepared using quaternisation of tri-tert-butyl- or tricyclohexylphosphine with decylbromide and subsequent bromide exchange with the weakly-coordinating anions BF(4)(-), PF(6)(-), SO(3)CF(3)(-), N(SO(2)CF(3))(2)(-). The salts obtained melt below 100 degrees C and possess a broad electrochemical window. Density functional theory combined with X-ray crystallography, IR and Raman spectroscopy has been used to analyze the molecular and supramolecular structures of the compounds obtained and their possible influence on their physical properties. PMID:20480083

Ermolaev, Vadim; Miluykov, Vasiliy; Rizvanov, Ildar; Krivolapov, Dmitriy; Zvereva, Elena; Katsyuba, Sergey; Sinyashin, Oleg; Schmutzler, Reinhard

2010-06-21

287

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

E-print Network

)3 or 1 converts biphenylene to tetraphenylene. The intermediates in the catalytic cycle have beenMechanistic Investigation of Catalytic Carbon-Carbon Bond Activation and Formation by Platinum(IV) intermediate. 2 reductively eliminates tetraphenylene at 115 °C. At 120 °C the reaction is catalytic; Pt(PEt3

Jones, William D.

288

Phosphine-Catalyzed Formation of Carbon-Sulfur Bonds: Catalytic Asymmetric Synthesis of gamma-Thioesters  

E-print Network

A method for catalytic asymmetric ? sulfenylation of carbonyl compounds has been developed. In the presence of an appropriate catalyst, thiols not only add to the ? position of allenoates, overcoming their propensity to ...

Sun, Jianwei

289

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

290

Three-coordinate, luminescent, water-soluble gold(I) phosphine complexes: structural characterization and photoluminescence  

E-print Network

characterization and photoluminescence properties in aqueous solution Zerihun Assefa a , Jennifer M. Forward The photoluminescent properties of several types of three-coordinate gold(I) complexes in organic solvents

Abdou, Hanan E.

291

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

292

O-Phenyl (tert-butyl­amido)(p-tolyl­amido)­phosphinate  

PubMed Central

In the title mol­ecule, C17H23N2O2P, the P atom has a distorted tetra­hedral environment. The P—N bond to the tolyl­amido fragment is 1.642?(4)?Å while that to the butyl­amido fragment is 1.629?(3)?Å. The dihedral angle between the two benzene rings is 82.3?(2)°. In the crystal, adjacent mol­ecules are linked via weak N—H?(O)P and N—H?N hydrogen-bonding inter­actions into an extended chain parallel to the b axis. The three methyl groups of the tert-butyl­amido substituent are disordered over two sets of sites with equal occupancies. The crystal studied was found to be a non-merohedral twin with the minor twin component = 23.1?(1)%. PMID:22199892

Pourayoubi, Mehrdad; Rheingold, Arnold L.; Chen, Chao; Karimi Ahmadabad, Fatemeh; Tarahhomi, Atekeh

2011-01-01

293

O-Phenyl (cyclo­hexyl­amido)(p-tolyl­amido)­phosphinate  

PubMed Central

In the title mol­ecule, C19H25N2O2P, the P atom is bonded in a distorted tetra­hedral environment. The dihedral angle between the two phenyl rings is 89.09?(8)°. The methyl H atoms are disordered over two sets of sites with equal occupancy. The O atom of the P=O group acts as a double hydrogen-bond acceptor of the type (N—H)2?(O=)P—, forming R 2 2(8) rings which are further linked into chains along [010]. PMID:21754869

Sabbaghi, Fahimeh; Pourayoubi, Mehrdad; Karimi Ahmadabad, Fatemeh; Parvez, Masood

2011-01-01

294

O-Phenyl (cyclo-hexyl-amido)(p-tolyl-amido)-phosphinate.  

PubMed

In the title mol-ecule, C(19)H(25)N(2)O(2)P, the P atom is bonded in a distorted tetra-hedral environment. The dihedral angle between the two phenyl rings is 89.09?(8)°. The methyl H atoms are disordered over two sets of sites with equal occupancy. The O atom of the P=O group acts as a double hydrogen-bond acceptor of the type (N-H)(2)?(O=)P-, forming R(2) (2)(8) rings which are further linked into chains along [010]. PMID:21754869

Sabbaghi, Fahimeh; Pourayoubi, Mehrdad; Karimi Ahmadabad, Fatemeh; Parvez, Masood

2011-06-01

295

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

296

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

297

The inhibiting effect of quaternary phosphine on Ni–P alloys in 1 M H2SO4  

Microsoft Academic Search

Polarization curves, electrochemical impedance measurements and SEM analysis were used to study the dissolution and the inhibition of nickel–phosphorous alloys in 1 M H2SO4. The alloy specimen was obtained by electroless plating on copper substrates. The inhibiting effect of triphenyl-alkyl (C6)-phosphonium (P3AP) was examined. The shape of the polarization curves remained essentially unchanged by addition of the inhibitor, but the

S. O. Niass; M. Ebn Touhami; N. Hajjaji; A. Srhiri; H. Takenouti

2001-01-01

298

Steric Effects on the Synthesis, Structure, Reactivity and Selectivity of t-Phosphine Rhodium Complex Hydroformylation Catalysts  

Microsoft Academic Search

Bulky trivalent phosphorus ligands of transition metal complexes were often observed to affect catalyst activity and selectivity. In the area of the low pressure hydroformylation of ?-olefins in the presence of rhodium complexes, Pruett and Smith observed early (1) that the use of bulky ortho-substituted phosphite ester ligands leads to a decrease of the ratio of straight chain versus branched

Alexis A. Oswald; Dan E. Hendriksen; Rodney V. Kastrup; Karl Irikura; Edmund J. Mozeleski; David A. Young

1987-01-01

299

N-(2,6-Difluoro­benzo­yl)-P,P-bis­(pyrrolidin-1-yl)phosphinic amide  

PubMed Central

The phosphoryl and carbonyl groups in the title compound, C15H20F2N3O2P, are anti with respect to each other (but the P- and C-groups are separated by another atom) and the P atom is in a tetra­hedral coordination environment. Two C atoms in one of the pyrrolidinyl fragments are disordered over two sets of sites with occupancies of 0.746?(8) and 0.254?(8). The environments of the pyrrolidinyl N atoms show a slight deviation from planarity and none of the three N atoms is involved in any hydrogen bond as an acceptor. In the crystal, pairs of inter­molecular N—H?O hydrogen bonds form inversion dimers. PMID:22059015

Pourayoubi, Mehrdad; Tarahhomi, Atekeh; Rheingold, Arnold L.; Golen, James A.

2011-01-01

300

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

E-print Network

, especially on hydrogenation of "largely unfunctionalized" alkenes, for more than a decade. These substrates, however, could not be easily modified leading to limited applications for organic synthesis. As a result, asymmetric hydrogenations of substrates...

Khumsubdee, Sakunchai

2013-11-05

301

Novel anionic phosphine transition metal hydride complexes and their application to the catalytic hydrogenation of polar organic compounds  

SciTech Connect

Potassium tris(triphenylphosphine) ruthenium hydride complexed with diethyl ether and naphthalene was an effective homogeneous catalyst in the hydrogenation, under mild conditions (85/sup 0/-90/sup 0/C and 620 kPa hydrogen), of acetone to isopropanol, propanol to n-propanol, acrolein to allyl alcohol (and propionaldehyde), activated carboxylic acid esters, e.g., methyl trifluoroacetate and dimethyl oxalate, to corresponding alcohols, and acetonitrile to ethylamine. In most reactions, the selectivity for the hydrogenated products was above 90 per cent.

Grey, R.A.; Pez, G.P.

1980-01-01

302

Mild and phosphine-free iron-catalyzed cross-coupling of nonactivated secondary alkyl halides with alkynyl Grignard reagents.  

PubMed

A simple protocol for iron-catalyzed cross-coupling of nonactivated secondary alkyl bromides and iodides with alkynyl Grignard reagents at room temperature has been developed. A wide range of secondary alkyl halides and terminal alkynes are tolerated to afford the substituted alkynes in good yields. A slight modification of the reaction protocol also allows for cross-coupling with a variety of primary alkyl halides. PMID:24754234

Cheung, Chi Wai; Ren, Peng; Hu, Xile

2014-05-01

303

Synthesis, characterization and structural determination of some nickel(II) complexes containing imido Schiff bases and substituted phosphine ligands  

NASA Astrophysics Data System (ADS)

Some new tridentate ONN Schiff base complexes of [NiL(PR3)] (where L = Salicylidene2-amino4-nitrobenzene (L1), 5-BrSalicylidene2-amino4-nitrobenzene (L2), 5-NO2Salicylidene2-amino4-nitrobenzene (L3), 5-MeOSalicylidene2-amino4-nitrobenzene (L4) and 3-MeOSalicylidene2-amino4-nitrobenzene (L5), R = Bu and Ph (with L1)) were synthesised and characterized by IR, UV-Vis, 1H NMR spectroscopy and elemental analysis. The geometry of [NiL1(PPh3)] was determined by X-ray crystallography. It indicated that the complex had a planar structure and four coordinates in the solid state. The thermogravimetry (TG) and differential thermoanalysis (DTA) of the synthesized complexes were carried out in the range of 20-600 °C, leading to the decomposition of L1-L3 type in three stages and of L4-L5 and [NiL1(PPh3)] type in four stages. Thermal decomposition of the complexes was closely the dependent upon the nature of the Schiff base ligands and proceeded via the first order kinetics.

Kianfar, Ali Hossein; Ebrahimi, Mostafa

2013-11-01

304

Synthesis, characterization and structural determination of some nickel(II) complexes containing imido Schiff bases and substituted phosphine ligands.  

PubMed

Some new tridentate ONN Schiff base complexes of [NiL(PR3)] (where L=Salicylidene2-amino4-nitrobenzene (L(1)), 5-BrSalicylidene2-amino4-nitrobenzene (L(2)), 5-NO2Salicylidene2-amino4-nitrobenzene (L(3)), 5-MeOSalicylidene2-amino4-nitrobenzene (L(4)) and 3-MeOSalicylidene2-amino4-nitrobenzene (L(5)), R=Bu and Ph (with L(1))) were synthesised and characterized by IR, UV-Vis, (1)H NMR spectroscopy and elemental analysis. The geometry of [NiL(1)(PPh3)] was determined by X-ray crystallography. It indicated that the complex had a planar structure and four coordinates in the solid state. The thermogravimetry (TG) and differential thermoanalysis (DTA) of the synthesized complexes were carried out in the range of 20-600°C, leading to the decomposition of L(1)-L(3) type in three stages and of L(4)-L(5) and [NiL(1)(PPh3)] type in four stages. Thermal decomposition of the complexes was closely the dependent upon the nature of the Schiff base ligands and proceeded via the first order kinetics. PMID:23892113

Kianfar, Ali Hossein; Ebrahimi, Mostafa

2013-11-01

305

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

SciTech Connect

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

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

2009-06-01

306

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

307

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

NASA Technical Reports Server (NTRS)

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

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

1987-01-01

308

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

309

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

310

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

311

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

2015-02-21

312

Calix[4]arene-phosphine dimers: precursors of flexible metallo-capsules and self-compacting molecules.  

PubMed

The first diphosphines based on a double calixarene, namely 1,4 (or 1,3)-bis-(5-diphenylphosphino-25,26,27,28-tetrapropoxycalix[4]aren-17-yl)benzene (L(2), L(3)) were each prepared in four steps starting from 5,17-dibromo-25,26,27,28-tetrapropoxycalix[4]arene. Upon reaction of L(2) with [Au(tht)(thf)]BF(4), (tht = C(4)H(8)S) a rigid metallo-capsule was quantitatively formed, which adopts an oblique form owing to the distinct nature of the spacers linking the two calixarene half-spheres. In the solid state, the 1,4-substituted phenylene linker is turned towards the gold ion, suggesting the existence of weak bonding interactions between two aromatic CH protons of this ring and the metal centre (AuH =2.67 A). In contrast to this gold complex, the related silver complex shows dynamic behaviour in solution, the exchange between two enantiomeric oblique forms being facilitated by the greater stereochemical flexibility of Ag(I) vs. Au(I). A heteronuclear (109)Ag{(1)H} HMQC experiment established strong correlations between the CH protons of the phenylene linker and the (109)Ag ion. Dynamic behaviour similar to that observed for the silver complex was further observed in trans-[PtCl(2)L(2)], a chelate complex that could be obtained quantitatively from L(2) and [PtCl(2)(PhCN)(2)]. The intended formation of a chelate complex leading to a capsule with an endo-oriented metal centre was achieved by reacting L(3) with [Pd(allyl)(thf)(2)]BF(4). The complex thus formed constitutes the first organometallic transition metal complex embedded in a cavity with large portals. Binding of [RuCl(2)(p-cymene)] to L(2) and L(3) resulted in self-compacting bimetallic complexes in which each calixarene basket entraps a Ru(p-cymene) unit, thereby forming molecules occupying a minimal volume. PMID:19725082

Sameni, Soheila; Jeunesse, Catherine; Matt, Dominique; Toupet, Loïc

2009-10-12

313

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

314

Part I. Synthesis, characterization, and reactivity of novel rhenium (V) phosphine complexes. Part II. Efficacy of computer-assisted labs  

Microsoft Academic Search

Part I describes the synthesis of the fac-cis and mer-trans isomers of ReOCl3(PEt3) 2 in high yield with the fac-cis isomer being structurally characterized by X-ray crystallography for the first time. The heptahydrides ReH7(PR3)2 and pentahydrides ReH5(PR 3)3 have been synthesized where R = Me, Et. The previously unreported compounds ReO(OR)Cl2(PMe3)2 and ReO(OR)Cl2(PEt3)2, where R = Me, Et, have been

Kimberly Jo Smith

2000-01-01

315

Melamine salt of bis(methylol)phosphinic acid (melaphene) as a regulator of Rauwolfia serpentina specialized metabolism  

Microsoft Academic Search

Earlier we have demonstrated that melaphene is a plant growth regulator, which is efficient at extremely low concentrations (10 ?8 to 10 ?7 %) [1]. However, the mechanism of its action is unknown. In this work, we studied the effects of melaphene on the alkaloid synthesis in plants. According to current knowledge, alkaloids fulfill diverse physiological functions favoring homeostasis maintenance

R. Yu. Kozlova; V. G. Vinter; S. G. Fattakhov; V. S. Reznik; A. I. Konovalov

2005-01-01

316

Low-temperature superstructure of [(N,N-diisobutyl­carbamo­yl)meth­yl]oct­yl(phen­yl)phosphine oxide (CMPO)  

PubMed Central

At 120?K, the title compound, C24H42NO2P, crystallizes in a unit cell with a doubled a parameter compared with the room-temperature structure. There are four mol­ecules in the asymmetric unit, one of which shows extensive disorder in a 0.588?(3):0.412?(3) ratio. In the crystal, numerous C—H?O inter­actions link the mol­ecules. PMID:22199779

Pojarová, Michaela; Fejfarová, Karla; Makrlík, Emanuel

2011-01-01

317

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

PubMed

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

Sgro, Michael J; Stephan, Douglas W

2012-06-14

318

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

E-print Network

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

Su, Mingjuan

319

Boron in the primary and secondary coordination spheres of iron and nickel  

E-print Network

Motivated by the reported electronic versatility of anionic tris(phosphine)borate and tris- (phosphine)sily1 ligands, a new, neutral tris(phosphine)borane scaffold was prepared. The synthesis, spectroscopy and solid-state ...

MacMillan, Samantha Nicole

2013-01-01

320

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

321

Propene and 1-Octene Hydroformylation with Silica-Supported, Ionic Liquid-Phase (SILP) Rh-Phosphine Catalysts in Continuous Fixed-Bed Mode  

Microsoft Academic Search

Supported ionic liquid-phase (SILP) catalysts were made by immobilizing Rh-monophosphine complexes of bis(m-phenylguanidinium)phenylphosphine 1 and NORBOS 2 ligands in 1-n-butyl-3-methylimidazolium hexafluorophosphate, [BMIM][PF6], on a silica support. The catalysts were active in continuous gas- and liquid-phase hydroformylation of propene and 1-octene, exhibiting TOFs up to 88 h-1 for SILP Rh-2 catalysts, while only low selectivities up to 74% n-aldehyde (n\\/iso ratio

Anders Riisager; K. Michael Eriksen; Peter Wasserscheid; Rasmus Fehrmann

2003-01-01

322

METAL-SELENIUM INTERACTIONS. SYNTHESIS AND CRYSTAL STRUCTURE OF [DIIODO{1,1?-METHYLENE-BIS (DIPHENYL PHOSPHINE SELENIDE)}] ZINC(II)  

Microsoft Academic Search

Reaction of 1,1?-methylenebis(diphenylphosphine selenide) {Ph2P(Se)—CH2—P(Se)Ph2, dpmSe2} with zinc(II) diiodide in dry diethylether-benzene mixture formed Znl2(dpmSe2) (1), which has been characterised with the help of analytical data, IR spectroscopy and single crystal X-ray crystallography. Zinc(II) is bonded to two iodine atoms {Zn—I, 2.5732(9), 2.5584(7) Å} and two selenium atoms {Zn—Se, 2.5135(8), 2.4906(10) Å}. The angles about Zn vary from 103.56(3) to

Tarlok S. Lobana; Rajbir Hundal; Peter Turner

2001-01-01

323

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

E-print Network

labile to hydrolysis, such as trimethyl borate. As mentionedborate because catecholborane might be a better boron source and it is more labile to hydrolysisborate was added followed by refluxing the reaction for 12 hours. After hydrolysis

Szeto, Judy

2014-01-01

324

Multimetallic arrays: symmetrical bi-, tri- and tetrametallic complexes based on the group 10 metals and the functionalisation of gold nanoparticles with nickel-phosphine surface units.  

PubMed

Homobimetallic complexes of nickel, palladium and platinum, [(L2M)2(S2CNC4H8NCS2)]2+, are formed on reaction of the piperazine bis(dithiocarbamate) linker, KS2CNC4H8NCS2K, with [MCl2L2] (M=Ni, L2=dppe, dppf; M=Pd, L2=dppf; M=Pt, L=PEt3, PMePh2, PPh3, L2=dppf). [{Pd(C,N-C6H4CH2NMe2)}2(S2CNC4H8NCS2)] can be obtained in the same way. On reaction of [MCl2L2] (M=Pd, Pt) with the zwitterion S2CNC4H8NH2, a symmetrisation process occurs to yield a mixture of the complexes [M(S2CNC4H8NH2)L2]2+ and [(L2M)2(S2CNC4H8NCS2)]2+. However, the monometallic complexes [L2Ni(S2CNC4H8NH2)]2+ (L2=dppe, dppf) and [(L2Ni)2(S2CNC4H8NCS2)]2+ can be prepared without ready symmetrisation. Starting from the previously reported [(dppm)Ru(S2CNC4H8NH2)]2+, the heterotrimetallic products [(dppm)Ru(S2CNC4H8NCS2)M(dppf)]2+ (M=Pd, Pt) can be prepared without symmetrisation occurring. The crystal structures of five complexes are reported. The metalla-dithiocarbamate complexes [L2Ni(S2CNC4H8NCS2)] (L2=dppe, dppf) were used to functionalise the surface of gold nanoparticles by the displacement of a citrate shell to yield NiAu and FeNiAu materials. PMID:19417934

Knight, Edward R; Leung, Nina H; Lin, Yvonne H; Cowley, Andrew R; Watkin, David J; Thompson, Amber L; Hogarth, Graeme; Wilton-Ely, James D E T

2009-05-21

325

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

326

Syntheses based on monocarbon molecules: I. Synthesis of menthyl isovalerate by hydrocarbalkoxylation of isobutylene with carbon monoxide and menthol in the presence of palladium-phosphine complexes  

SciTech Connect

The kinetics of isobutylene carbalkoxylation with carbon monoxide and menthol in the presence of the catalytic system Pd(OAc){sub 2} + PPh{sub 3} + p-CH{sub 3}C{sub 6}H{sub 4}SO{sub 3}OH was studied. The optimal conditions for the synthesis of menthyl isovalerate, which is the main active component in validol medicine, were determined. 4 refs., 3 figs.

Suerbaev, K.A.; Tsukanov, I.A.; El`man, A.R. [Al`-Farabi Kazakh State Univ., Alma-Ata (Kazakhstan)] [and others

1995-01-10

327

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

E-print Network

of Model Alkyl-, Aryl-, and Ethoxyphosphonium Salts J. Sommer, Y. Yang, D. Rambow, and J. Blu1mel to leaching of adsorbed catalysts that are not bound covalently, the exact nature of the surface- bound side [(31 P), CSA], it is demonstrated that the side product is an ethylphosphonium salt bound

Bluemel, Janet

328

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

329

Extraction from HNO{sub 3} solutions and separation of Pu(IV) from Am(III) by diphenyl(dialkyl carbamoylmethyl)phosphine oxides  

SciTech Connect

Five carbamoylmethylphosphine oxide (CMPO) extractants with phenyl substituents on the P atom and alkyl groups (butyl, octyl, isoamyl) or cyclic hydrocarbons (piperidine, morpholine) on the N atom are used to study the extraction of Pu(IV) from HNO{sub 3} solutions by CMPO in a polar aromatic fluorinated diluent as a function of [HNO{sub 3}] and [CMPO]. All studied CMPOs quantitatively extract Pu(IV) from HNO{sub 3} with distribution coefficients that are 2-3 orders of magnitude greater than those of Am(III). The elements Pu and Am can be separated during back-extraction.

Litvina, M.N.; Chmutova, M.K.; Nesterova, N.P. [V.I. Vernadskii Institute of Geochemistry and Analytical Chemistry, Moscow (Russian Federation)] [and others

1995-03-01

330

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

331

Dinuclear NHC-palladium complexes containing phosphine spacers: synthesis, X-ray structures and their catalytic activities towards the Hiyama coupling reaction.  

PubMed

Six dinuclear N-heterocyclic carbene (NHC) palladium complexes, [PdCl2(IMes)]2(?-dppe) (1), [PdCl2(IPr)]2(?-dppe) (2), [PdCl2(IMes)]2(?-dppb) (3), [PdCl2(IPr)]2(?-dppb) (4), [PdCl2(IMes)]2(?-dpph) (5), and [PdCl2(IPr)]2(?-dpph) (6) [IMes = N,N'-bis-(2,4,6-trimethylphenyl)imidazol-2-ylidene; IPr = N,N'-bis-(2,6-di(iso-propyl)phenyl)imidazol-2-ylidene; dppe = 1,2-bis(diphenylphosphino)ethane, dppb = 1,4-bis(diphenylphosphino)butane; and dpph = 1,6-bis(diphenylphosphino)hexane], have been synthesized through bridge-cleavage reactions of chloro-bridged dimeric compounds, [Pd(?-Cl)(Cl)(NHC)]2, with the corresponding diphosphine ligands. The obtained compounds were fully characterized by (1)H NMR, (13)C NMR and (31)P NMR spectroscopy, FT-IR, elemental analysis and single-crystal X-ray crystallography. Moreover, further explorations of the catalytic potential of the dinuclear carbene palladium complexes as catalysts for the Pd-catalyzed transformations have been performed under microwave irradiation conditions, and the complexes exhibited moderate to good catalytic activity in the Hiyama coupling reaction of trimethoxyphenylsilane with aryl chlorides. PMID:24671375

Yang, Jin; Li, Pinhua; Zhang, Yicheng; Wang, Lei

2014-05-21

332

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

333

Laboratory measurements of the W band (3.2 mm) properties of phosphine (PH3) and ammonia (NH3) under simulated conditions for the outer planets  

NASA Astrophysics Data System (ADS)

A model, based on the Van Vleck-Weisskopf line shape, was developed for the centimeter-wavelength opacity of PH3, which provides an order of magnitude improvement over previous models [Hoffman et al., 2001]. New laboratory measurements indicate that the model is also accurate at 94 GHz (3.2 mm) under conditions for the outer planets. Measurements of the opacity and refractivity of PH3 in a hydrogen/helium (H2/He) atmosphere were conducted at 94 GHz (3.2 mm) at pressures of 0.5 and 2 bars and at temperatures of 293 K and 213 K. Additionally, new high-precision laboratory measurements of the opacity and refractivity of NH3 in an H2/He atmosphere were conducted at the same frequency at pressures from 0.5 to 2 bars and at temperatures of 204 K, 211 K, and 290 K. Results show that existing models, which predict NH3 opacity in an H2/He environment, understate the absorption due to the pressure broadened rotational lines. A new model is proposed for use at 94 GHz (3.2 mm) which uses a Ben-Reuven line shape [Ben-Reuven, 1966] for the inversion lines and a Kinetic line shape [Gross, 1955] for the rotational lines. Results of measurements of both PH3 and NH3 can be used to better interpret maps of Saturn's emission at this wavelength and can potentially be used to deduce spatial variations in the abundances of both gases in the atmosphere of Saturn.

Mohammed, Priscilla N.; Steffes, Paul G.

2004-07-01

334

Hydrogenation of aqueous mixtures of calcium carbonate and carbon dioxide using a water-soluble rhodium(I)–tertiary phosphine complex catalyst  

Microsoft Academic Search

Aqueous suspensions of calcium carbonate were hydrogenated to yield calcium formate under a gas phase containing both H2 and CO2. A rhodium(I)-complex of monosulfonated triphenylphosphine (mtppms), [RhCl(mtppms)3] was used as catalyst. Reaction temperatures were in the range of 20–70°C, total pressure 10–100bar with an optimum p(CO2):p(H2) ratio of 1:4. Due to the mobile bicarbonate-formate equilibrium, the highest available formate concentration

István Jószai; Ferenc Joó

2004-01-01

335

Theoretical investigation on the electronic structures and phosphorescent properties of a series of Ir(III) complexes with the diphenyl(1-naphthyl)phosphine ancillary ligand  

NASA Astrophysics Data System (ADS)

The electronic structures, photophysical properties, and potential organic light-emitting diodes (OLEDs) applications of a series of Ir(III) complexes 1-6 have been theoretically investigated by using the density functional theory (DFT) method. The photophysical properties of these complexes are greatly affected by the different substituents on the cyclometalated ligands. The phosphorescence wavelength, quantum yields, and luminescent efficiency of these complexes also are closely related to the ?-conjugation length, substitution positions, and substituents inductive effect for the cyclometalated ligands. The designed complex 5 could be a potential candidate as a blue-emitting material with a high quantum efficiency.

Shang, Xiaohong; Han, Deming; Guan, Shuang; Wang, Xiaofeng; Zhang, Gang

2014-10-01

336

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

337

Activation of a (cyclooctadiene) rhodium(I) complex supported by a chiral ferrocenyl phosphine thioether ligand for hydrogenation catalysis: a combined parahydrogen NMR and DFT study.  

PubMed

The reaction of [RhCl(P,S(t)Bu)(COD)] (1) or [Rh(P,S(t)Bu)(COD)]BF4 (2) where (P,S(t)Bu) is CpFe[?(5)-1,2-C5H3(PPh2)(CH2S(t)Bu)] with H2 in MeOH gives rise to COD hydrogenation and formation of a solvent-stabilized product. The formation of hydride species cannot be observed in view of a very rapid H/D exchange between H2 and the solvent. Introduction of pyridine or acetonitrile slows down this exchange process and allows observation of diastereometric dihydride complexes, [Rh(P,S(t)Bu)(H)2(L)2](+), the stereochemistry of which was fully elucidated. The hydride site exchange rates have been derived from EXSY NMR experiments and used, with assistance from DFT calculation, to elucidate the isomerization and site exchange mechanisms. PMID:23851567

Kozinets, Ekaterina M; Fekete, Marianna; Filippov, Oleg A; Belkova, Natalia V; Shubina, Elena S; Poli, Rinaldo; Duckett, Simon B; Manoury, Eric

2013-08-28

338

DOI: 10.1002/adsc.200((will be filled in by the editorial staff)) An Easy, Stereoselective Synthesis of Hexahydroisoindol-4-ones  

E-print Network

2. Synthesis of pyrrolines from conjugated dienes and imines under phosphine catalysis.[7, Stereoselective Synthesis of Hexahydroisoindol-4-ones under Phosphine Catalysis Deepti Duvvuru,a Jean-arylsulfonylimines and cyclic conjugated dienes, under phosphine catalysis. Key substrates are 3-vinylcyclohex-2-enones

Boyer, Edmond

339

Thermoregulated phase transfer ligands and catalysis  

Microsoft Academic Search

A series of nonionic surface-active phosphine ligands with the general formula, , (AEOPP) has been synthesized. Cloud points of the phosphine ligands are measured and effects of changing hydrophilic and lipophilic groups on the cloud point of the phosphine ligand are examined. Experiment shows that AEOPP has distinct cloud point when n is greater than 7, R group larger than

Jinayang Jiang; Yanhua Wang; Chun Liu; Fushe Han; Zilin Jin

1999-01-01

340

Green synthesis of Pd/CuO nanoparticles by Theobroma cacao L. seeds extract and their catalytic performance for the reduction of 4-nitrophenol and phosphine-free Heck coupling reaction under aerobic conditions.  

PubMed

We report the green synthesis of palladium/CuO nanoparticles (Pd/CuO NPs) using Theobroma cacao L. seeds extract and their catalytic activity for the reduction of 4-nitrophenol and Heck coupling reaction under aerobic conditions. The catalyst was characterized using the powder XRD, TEM, EDS, UV-vis and FT-IR. This method has the advantages of high yields, elimination of surfactant, ligand and homogeneous catalysts, simple methodology and easy work up. The catalyst can be recovered from the reaction mixture and reused several times without any significant loss of catalytic activity. PMID:25721860

Nasrollahzadeh, Mahmoud; Sajadi, S Mohammad; Rostami-Vartooni, Akbar; Bagherzadeh, Mojtaba

2015-06-15

341

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

-orbital can introduce a polarization to the s-orbital for a bound hydrogen atom. Many properties depend on the wave function tail, far from the nucleus; to describe molecules with loosely bound electrons, such as anions, the basis functions with small...

Surawatanawong, Panida

2010-07-14

342

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

Microsoft Academic Search

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

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

2005-01-01

343

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

PubMed

An extensive series of 3:1 site-differentiated cubane-type clusters [Fe(4)S(4)(PPr(i)(3))(3)L] (L = Cl(-), Br(-), I(-), RO(-), RS(-), RSe(-)) has been prepared in 40-80% yield by two methods: ligand substitution of [Fe(4)S(4)(PPr(i)(3))(4)](1+) in tetrahydrofuran (THF)/acetonitrile by reaction with monoanions, and reductive cleavage of ligand substrates (RSSR, RSeSeR, I(2)) by the all-ferrous clusters [Fe(8)S(8)(PPr(i)(3))(6)]/[Fe(16)S(16)(PPr(i)(3))(8)] in THF. These neutral clusters are stable and do not undergo ligand redistribution reactions involving charged species in benzene and THF solutions. X-ray structural studies confirm the cubane stereochemistry but with substantial and variable distortions of the [Fe(4)S(4)](1+) core from idealized cubic core geometry. Based on Fe-S bond lengths, seven clusters were found to have compressed tetragonal distortions (4 short and 8 long bonds), and the remaining seven display other types of distortions with different combinations of long, short, and intermediate bond lengths. These results further emphasize the facile deformabililty of this core oxidation state previously observed in [Fe(4)S(4)(SR)(4)](3-) clusters. The Fe(2.25+) mean oxidation state was demonstrated from (57)Fe isomer shifts, and the appearance of two quadrupole doublets arises from the spin-coupled |9/2,4,1/2> state. The S = 1/2 ground state was further supported by electron paramagnetic resonance spectra and magnetic susceptibility data. PMID:21038882

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

2010-12-01

344

Branched tetrasilane substituted phosphines - synthesis and characterisation of PhSi(SiiPr2)3P and {PhSi(SiMe2)3}2P14.  

PubMed

The branched trichlorotetrasilane PhSi(SiMe2Cl)3 reacts with P7(SiMe3)3 leading to formation of a new oligophosphane {PhSi(SiMe2)3}2P14 (1), which consists of two PhSi(SiMe2)3 substituted P7 norbornane units. The phosphatetrasila[1.1.1]pentane derivative PhSi(SiiPr2)3P (3) was obtained from the reaction of PhSi(SiiPr2Cl)3 (2) with Li3P. PMID:24609409

Feierabend, Michael; von Hänisch, Carsten

2014-05-01

345

Synthesis, characterisation and thermal studies of ruthenium(II) carbonyl complexes of functionalised tripodal phosphine chalcogen donor ligands, [CH 3C(CH 2P(X)Ph 2) 3], where X = Se, S, O  

NASA Astrophysics Data System (ADS)

The polymeric ruthenium(II) carbonyl complex, [Ru(CO) 2Cl 2] n reacts with 1,1,1-tris-(diphenylphosphinomethyl)ethane trichalcogenide ligands, [CH 3C(CH 2P(X)Ph 2) 3], where X = Se( a), S( b) and O( c) in 1:1 (metal:ligand) molar ratio to afford hexa-coordinated complexes of the type ? 2-(X,X)-[Ru(CO) 2Cl 2P 3X 3] ( 1a- c). The complexes 1a- c exhibit two equally intense ?(CO) bands in the range 1979-2060 cm -1 indicating cis-disposition of the two terminal carbonyl groups. The values of ?(CO) frequencies containing different ligands, in general, follow the order: P 3O 3 > P 3S 3 > P 3Se 3 which may be explained in terms of 'Soft-Hard' (Ru(II)-O) and 'Soft-Soft' (Ru(II)-S/Se) interactions. The complexes have been characterized by elemental analyses, mass, 1H, 31P, 77Se and 13C NMR spectroscopy. The thermal stability of the complexes has also been studied.

Deb, Biswajit; Sarmah, Bhaskar Jyoti; Borah, Bibek Jyoti; Dutta, Dipak Kumar

2009-03-01

346

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

PubMed

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

Rostamnia, Sadegh; Liu, Xiao; Zheng, Dan

2014-10-15

347

The [MoFe3S4]2+ Oxidation State: Synthesis, Substitution Reactions, and Structures of Phosphine-Ligated Cubane-Type Clusters with the S = 2 Ground State  

PubMed Central

The cluster [(Tp)MoFe3S4(PEt3)3]1+ containing the cubane-type [MoFe3(?3-S)4]2+ reduced core undergoes facile ligand substitution reactions at the iron sites leading to an extensive set of mono- and disubstituted species [(Tp)MoFe3S4(PEt3)3-nLn]1-n with L = halide, N3-, PhS-, PhSe-, R3SiO-, and R3SiS- and n = 1 and 2. Structures of 10 members of the set are reported. For two representative clusters, Curie behavior at 2-20 K indicates a spin-quintet ground state. Zero-field Mössbauer spectra consist of two doublets in a 2:1 intensity ratio. 57Fe isomer shifts are consistent with the mean oxidation state Fe32.33+ arising from electron delocalization of the mixed-valence oxidation state description [Mo3+Fe3+Fe2+2]. Reaction of [(Tp)MoFe3S4(PEt3)2Cl] with (Me3Si)2S affords [(Tp)MoFe3S4(PEt3)2(SSiMe3)], a likely first intermediate in the formation of the tricluster compound {[(Tp)MoFe3S4(PEt)2]3S}(BPh4) from the reaction of [(Tp)MoFe3S4(PEt3)3](BPh4) and NaSSiMe3 in THF. The tricluster consists of three cluster units bound to a central ?3-S atom in a species of overall C3 symmetry. Relatively few clusters in the [MoFe3S4]2+ oxidation state have been prepared compared to the abundance of clusters in the oxidized [MoFe3S4]3+ state. This work is the first comprehensive study of the [MoFe3S4]2+ state, one conspicuous feature of which is its ability to bind hard and soft ?-donors and strong to weak ?-acid ligands. (Tp = tris(pyrazolyl)hydroborate(1-)) PMID:21648449

Xi, Bin

2011-01-01

348

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

PubMed

Treatment of [Et4N][Tp*WS3] (Tp* = hydridotris(3,5-dimethylpyrazol-1-yl)borate) (1) with CuX (X = Br, SCN) and PPh3 or 1,1-bis(diphenylphosphino)methane (dppm) produced two neutral trinuclear clusters [Tp*W(?3-S)(?-S)2Cu2Br(PPh3)] (2) and [Tp*W(?3-S)(?-S)2Cu2(SCN)(dppm)]2·MeCN·Et2O (3·MeCN·Et2O). Reactions of 1 with [Cu(MeCN)4]PF6, NH4PF6 and 1,3-bis(diphenylphosphino)propane (dppp), N,N-bi(diphenylphosphanylmethyl)-2-aminopyridine (bdppmapy), N,N,N',N'-tetra(diphenylphosphanylmethyl)ethylenediamine (dppeda), or 1,4-N,N,N',N'-tetra(diphenylphosphanylmethyl)benzenediamine (dpppda) afforded four clusters containing butterfly-shaped [Tp*WS3Cu2] cores, [Tp*W(?3-S)(?-S)2Cu2(dpppds)](PF6)·1.25MeCN (dpppds = 1,3-bis(diphenylphosphino)propane disulfide) (4·1.25MeCN), [Tp*W(?3-S)(?-S)2Cu2(bdppmapy)](PF6)·3MeCN (5·3MeCN) and {[Tp*W(?3-S)(?-S)2Cu2]2(L)]}(PF6)2·Sol (6·Et2O: L = dppeda, Sol = Et2O; 7·1.25MeCN: L = dpppda, Sol = 1.25MeCN). Compounds 2-7 were characterized by elemental analysis, IR, UV-Vis, (1)H and (31)P{(1)H} NMR spectra, electrospray ion mass spectra (ESI-MS) and single-crystal X-ray diffraction. Compound 2 or 3 has a butterfly-shaped [Tp*WS3Cu2] core in which one [Tp*WS3] unit binds two Cu(I) centers via one ?3-S and two ?-S atoms. In the cationic structure of 4 or 5, one in situ-formed dpppds or bdppmapy combines with the [Tp*WS3Cu2] core via each of its two S atoms or two P atoms coordinated at each Cu(I) center. In the bicationic structure of 6 or 7, two [Tp*WS3Cu2] cores are linked by one dppeda or dpppda bridge to form a bicyclic structure. The isolation of 2-7 with unstable [Tp*WS3Cu2] cores may be ascribed to the coordination of P- or S-donor ligands at Cu(i) centers of these cores. The third-order nonlinear optical (NLO) properties of 2-7 in DMF were also investigated by using the femtosecond degenerate four-wave mixing (DFWM) technique at 800 nm. PMID:24473639

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

2014-03-28

349

Removal of Heavy Metals from Aqueous Solutions by Precipitation-Filtration Using Novel OrganoPhosphorus Ligands  

Microsoft Academic Search

An organophosphorus mixture of sodium mono- and di-(n-hexa-decyl) phosphinate was synthesized and purified, and then used as a ligand to remove heavy metals by precipitation from aqueous nitrate, chloride, and sulfate solutions. The new ligand offers more advantages over the previously studied sodium dioctyl and dodecyl phosphinates. The sodium form of the mono- and di-(n-hexa-decyl) phosphinate has a much lower

Jamaleddin Esalah; Maen M. Husein

2008-01-01

350

ToxFAQs  

MedlinePLUS

... Flame Retardants * Other Languages... Phosphine | Fosfina Plutonium * Other Languages... Polybrominated Biphenyls (PBBs) & Polybrominated Diphenyl Ethers (PBDEs) | Polibromobifenilos Polybrominated Biphenyls (PBBs) & Polybrominated Diphenyl ...

351

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

352

Dissociation constants of organophosphinic acid compounds.  

PubMed

The dissociation equilibria of di(2,4,4-trimethylpentyi) phosphinic acid, mono(2,4,4-trimethylpentyl) phosphinic acid, di(n-octyl)phosphinic acid and mono(n-octyl)phosphinic acid have been studied in ethanol-water mixtures by potentiometric titration at 25 degrees C. These data have been analysed both graphically numerically using the program LETAGROP-ZETA. The obtained pK(a) values have been correlated with the corresponding values in water, determined both indirectly by means of extraction measurements and by estimation using the suitable Hammett equation. PMID:18965787

Martinez, M; Miralles, N; Sastre, A; Bosch, E

1993-09-01

353

Conjugate and method for forming aminomethyl phosphorus conjugates  

DOEpatents

A method of forming phosphine-amine conjugates includes reacting a hydroxymethyl phosphine group of an amine-free first molecule with at least one free amine group of a second molecule to covalently bond the first molecule with the second molecule through an aminomethyl phosphorus linkage and the conjugates formed thereby.

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

1999-01-01

354

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

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

2015-02-01

355

Breaking news on the enantioselective intermolecular Heck reaction.  

PubMed

Glowing results with less phosphorus: Tremendous progress has been made recently in asymmetric intermolecular Heck chemistry. Previously unprecedented enantioselective Heck-Matsuda reactions have been accomplished, and mixed phosphine/phosphine oxides have been shown to be superior ligands in enantioselective Mizoroki-Heck reactions. All of this was achieved with chiral ligands containing few or even no phosphorus donors (see scheme). PMID:24481834

Oestreich, Martin

2014-02-24

356

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

357

Study of nonbonding orbitals of phosphoryl oxygen by probing with ions with open d-shells  

Microsoft Academic Search

To evaluate the complex-forming properties of the oxygen in the phosphoryl group in phosphine oxide derivatives as a function of the hydrocarbon substituent, it is proposed to study the absorption spectra in the visible region of colored complexes of phosphine oxide derivatives with metal salts possessing unfilled d- or f-shells. When cobalt (II) chloride was used for this purpose, it

K. B. Yatsimirskii; Z. A. Sheka; E. I. Sinyavskaya

1970-01-01

358

EFFECT OF LEWIS ACIDIC METALS ON ARYL-OXYGEN BOND ACTIVATION IN NICKEL(0) DIPHOSPHINE MODEL SYSTEMS  

E-print Network

be converted to the more reactive phosphinates, sulfunates, or triflates. While catalytic systems are known phosphines such as tricyclohexylphosphine or carbenes. The common catalytic systems for these activations of nitrile groups. In 1984, Tolman et. al. observed that the catalytic hydrocyanation of olefins by Ni(0

Winfree, Erik

359

Poly(arylene ether)s That Resist Atomic Oxygen  

NASA Technical Reports Server (NTRS)

Novel poly(arylene ether)s containing phosphine oxide (PAEPO's) made via aromatic nucleophilic displacement reactions of activated aromatic dihalides (or, in some cases, activated aromatic dinitro compounds) with new bisphenol monomers containing phosphine oxide. Exhibited favorable combination of physical and mechanical properties and resistance to monatomic oxygen in oxygen plasma environment. Useful as adhesives, coatings, films, membranes, moldings, and composite matrices.

Connell, John W.; Hergenrother, Paul; Smith, Joseph G., Jr.

1994-01-01

360

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

361

Conjugate and method for forming aminomethyl phosphorus conjugates  

SciTech Connect

A method of forming phosphine-amine conjugates includes reacting a hydroxymethyl phosphine group of an amine-free first molecule with at least one free amine group of a second molecule to covalently bond the first molecule with the second molecule through an aminomethyl phosphorus linkage and the conjugates formed thereby.

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

1999-09-07

362

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

PubMed

Direct synthesis of free (alpha-hydroxyalkyl)phosphinic acid amphiphiles 1 can be readily realized by sonication of the heterogeneous mixture of 50% aqueous hypophosphorous acid and long-chain aldehydes in the presence of catalytic amounts of hydrochloric acid. Oxidation of these phosphinic acids by DMSO in the presence of catalytic amounts of iodine quantitatively leads to the corresponding phosphonic acids 3. IR spectra of the phosphinic acids 1 in the condensed phase and in solution reveal the presence of intra- and intermolecular associations. Dissociation constants of the phosphorus acids 1 and 3 determined by potentiometric and (31)P NMR titrations show a good correlation between the two methods. The phosphinic acid amphiphiles 1 are slightly stronger than the corresponding phosphonic acids 3. (alpha-Hydroxyalkyl)phosphonium chlorides are prepared in good yields from the phosphine PH(3) and long-chain aldehydes in acidic media. PMID:11672364

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

1998-10-16

363

Polyphosphazine-based polymer materials  

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.; Avci, Recep; Groenewold, Gary S.

2010-05-25

364

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

365

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

366

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

367

Recent Advances in Synthesis of P-BH3 Compounds.  

PubMed

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

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

2015-01-01

368

Two distinct allosteric active sites regulate guest binding within a Fe?Mo??¹?? cubic receptor.  

PubMed

The binding of phosphine ligands to molybdenum sites on the faces of a supramolecular cube served to inhibit allosterically the encapsulation of a neutral or anionic guest. The edges of the cube also provided a distinct second allosteric site, where the binding of tetraphenylborate also allosterically inhibited anion binding in the cube's cavity. The two allosteric sites were shown to regulate the binding of an anionic guest either independently or in concert. The use of a tertiary amine as an allosteric effector also enabled a phosphine guest to be ejected from the cube's cavity into solution, to generate phosphine complexes with other metal ions. PMID:24754534

Ramsay, William J; Nitschke, Jonathan R

2014-05-14

369

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

370

Macrocyclization by Nickel-Catalyzed, Ester-Promoted, Epoxide-Alkyne Reductive Coupling: Total Synthesis of (?)-Gloeosporone  

E-print Network

Ringing the changes: The total synthesis of the title compound centers around a novel strategy that employs a nickel(0)–phosphine complex and triethyl borane in an efficient closure of a 14-membered ring through C--C bond ...

Trenkle, James?D.

371

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

372

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

373

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

374

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

375

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

376

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.

377

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

378

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

379

Ligand-Controlled Asymmetric Arylation of Aliphatic ?-Amino Anion Equivalents  

PubMed Central

A palladium-catalyzed asymmetric arylation of 9-aminofluorene-derived imines using a chiral dialkylbiaryl phosphine as the supporting ligand has been developed. This transformation allows for enantioselective access to a diverse range of ?-branched benzylamines. PMID:24621247

2015-01-01

380

Ligand-controlled asymmetric arylation of aliphatic ?-amino anion equivalents.  

PubMed

A palladium-catalyzed asymmetric arylation of 9-aminofluorene-derived imines using a chiral dialkylbiaryl phosphine as the supporting ligand has been developed. This transformation allows for enantioselective access to a diverse range of ?-branched benzylamines. PMID:24621247

Zhu, Ye; Buchwald, Stephen L

2014-03-26

381

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

382

Palladium-Catalyzed Conversion of Aryl and Vinyl Triflates to Bromides and Chlorides  

E-print Network

The palladium-catalyzed conversion of aryl and vinyl triflates to aryl and vinyl halides (bromides and chlorides) has been developed using dialkylbiaryl phosphine ligands. A variety of aryl, heteroaryl, and vinyl halides ...

Shen, Xiaoqiang

2010-01-01

383

Nitrogen atom transfer from iron(IV) nitrido complexes: a dual-nature transition state for atom transfer.  

PubMed

The mechanism of nitrogen atom transfer from four-coordinate tris(carbene)borate iron(IV) nitrido complexes to phosphines and phosphites has been investigated. In the absence of limiting steric effects, the rate of nitrogen atom transfer to phosphines increases with decreasing phosphine ?-basicity. This trend has been quantified by a Hammett study with para-substituted triarylphosphines, and is contrary to the expectations of an electrophilic nitrido ligand. On the basis of electronic structure calculations, a dual-nature transition state for nitrogen atom transfer is proposed, in which a key interaction involves the transfer of electron density from the nitrido highest occupied molecular orbital (HOMO) to the phosphine lowest unoccupied molecular orbital (LUMO). Compared to analogous atom transfer reactions from a 5d metal, these results show how the electronic plasticity of a 3d metal results in rapid atom transfer from pseudotetrahedral late metal complexes. PMID:21902179

Scepaniak, Jeremiah J; Margarit, Charles G; Harvey, Jeremy N; Smith, Jeremy M

2011-10-01

384

Fluorinated 1,3-diketones, 2-trifluoroacetyl phenols and their derivatives: versatile reactants in phosphorus chemistry  

Microsoft Academic Search

The role of fluorinated ?-diketones, their tautomers (keto–enols) and their derivatives as reagents towards ?3P compounds is reviewed, including 2-trifluoroacetyl phenols, possessing formally a keto–enol system, and their derivatives. In an ‘insertion’ reaction phosphine and the keto–enol tautomers of 1,1,1,5,5,5-hexafluoro- and 1,1,1-trifluoropentan-2,4-dione furnished primary (S) or (R) ?-hydroxy phosphines, whose enol functions probably isomerized the corresponding keto compounds. Further addition

Ralph-Matthias Schoth; Dmitrii Sevenard; Kazimir Pashkevich; Gerd-Volker Röschenthaler

2000-01-01

385

Methemoglobinemia in aluminum phosphide poisoning  

Microsoft Academic Search

Introduction. Acute aluminum phosphide (AlP) poisoning is one of the most common causes of acute pesticide poisoning in Iran. Hydrogen phosphide or phosphine gas is produced following reaction of AlP with water even at ambient humidity. Methemoglobinemia is a rare finding following phosphine poisoning. In this paper, two cases of fatal AlP poisoning complicated by methemoglobinemia are reported. Case Report.

Shahin Shadnia; Kambiz Soltaninejad; Hossein Hassan ian-Moghadam; Anahaita Sadeghi; Hormat Rahimzadeh; Nasim Zamani; Alireza Ghasemi-Toussi; Mohammad Abdollahi

2011-01-01

386

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

387

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

PubMed Central

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

2013-01-01

388

Aqueous Partitioning of Minor Actinides by Different Processes  

Microsoft Academic Search

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

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

2011-01-01

389

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

390

Structural, electrical and optical characterization of N- and P-type SiC:H films deposited using ECR-CVD  

Microsoft Academic Search

Hydrogenated silicon carbide films (SiC:H) were deposited using the electron cyclotron resonance chemical vapour deposition (ECR-CVD) method from a mixture of methane, silane and hydrogen, and using diborane and phosphine as doping gases. The effects of changes in the diborane and phosphine levels on the optical bandgap and conductivity were investigated. In the case of boron-doped films, there is evidence

S. F. Yoon

1997-01-01

391

Investigation of the stability of the M-H-B bond in borane sigma complexes [M(CO)5(eta1-BH2R.L)] and [CpMn(CO)2(eta1-BH2R.L)] (M=Cr, W; L=tertiary amine or phosphine): substituent and Lewis base effects.  

PubMed

We investigated the influence of a substituent and a Lewis base on boron upon the thermodynamic stability of metal complexes of borane-Lewis base adducts, [M(CO)5(eta1-BH(2)R.L)] (M=Cr, W) and [CpMn(CO)2(eta1-BH2R.L)], where R=Cl, I, m-C6H4F, Ph, H, Me, Et; L=PMe3, PPh3, NMe3, quinuclidine. In these compounds, the stability of the metal-borane linkage was enhanced by increasing the electron-releasing ability of the substituent on boron. A stronger base L additionally stabilized the complexes. The strength of the borane-metal interaction is thus mainly ascribed to the electron donation from the BH sigma orbital to metal rather than the back-donation into the BH sigma* orbital. This result supports the bonding model for the B-H-M linkage in the borane complexes suggested by MO calculations, where the borane-to-metal electron donation is predominant while the metal back-donation into the BH sigma* orbital is negligible. Such a stability trend of the borane complexes makes a sharp contrast to that of many silane and dihydrogen complexes. PMID:17525921

Kawano, Yasuro; Yamaguchi, Kazunori; Miyake, Shun-ya; Kakizawa, Taeko; Shimoi, Mamoru

2007-01-01

392

Synthesis of the Spiro Derivatives of 1,2-Oxaphosphetes by [2+2] Cycloaddition of Cyclic 1-(2,4,6-Triisopropylphenyl)phosphine Oxides with Dimethyl Acetylenedicarboxylate † † Preliminary communication: Keglevich, Gy.; Forintos, H.; Szöll?sy, Á.; T?ke, L. Chem. Commun. 1999, 1423–1424  

Microsoft Academic Search

Members of a new heterocyclic family, 1,2-oxaphosphetes were prepared by the unexpected [2+2] cycloaddition of the P?O group of 1-(2,4,6-triisopropylphenyl) P-heterocycles with the acetylene moiety of dimethyl acetylenedicarboxylate. The new oxaphosphetes are spiro derivatives of the starting heterocycles and exhibit a phosphorus atom with trigonal bipyramidal geometry. PM3 semiempirical calculations justified the novel reaction path and suggested a stepwise reaction

György Keglevich; Henrietta Forintos; György Miklós Keser?; László Heged?s; László T?ke

2000-01-01

393

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

394

Reactions of rhodium chloro complexes containing secondary phosphines with metal carbonyls [M 3(CO) 12](M = Fe, Ru): Synthesis and X-ray crystal structures of the metal clusters [Ru 3Rh(CO) 7( ? 3-H)( ?-PBu 2 t) 2(Bu 2 tPH)( ?-Cl) 2] and [Ru 3Rh(CO) 8( ? 3-H)( ?-H) 2( ? 3-PBu t)( ?-PBu 2 t) 2  

Microsoft Academic Search

The reactions of [RhCl(Bu2tPH)3] (1) and [RhCl(Bu2tPH)22] (2), respectively, with the metal carbonyls [M3(CO)12](M = Fe, Ru) in refluxing toluene have been investigated. By using [Fe3(CO)12] cluster degradation occurred and the known heterobimetallic complex [FeRh(CO)5(?-PBu2t)(Bu2tPH)] (6), in addition to the mononuclear compound [Fe(CO)4(Bu2tPH)] (7), was obtained. On the contrary, the reaction of 1 and 2, respectively, with [Ru3(CO)12] leads under

Hans-Christian Böttcher; Marion Graf; Kurt Merzweiler

1997-01-01

395

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

396

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

PubMed

The insertion of CO2 into the (PSiP)palladium-allyl bond has been investigated using DFT. Three possible modes of CO2 insertion into (PSiP)Pd-allyl bond have been calculated, that is, direct 1.2-insertion mode, metallo-ene mode, and SE2 mode. The metallo-ene mode is the most favorable via the six-membered ring transition state. The results of calculations are consistent with the regioselectivity observed experimentally. The steric and electronic effects of different phosphine substituents have been evaluated by ONIOM and energy decomposition analysis (EDA) methods. For the phosphine substituents P(i-Pr)2 and PPh2, the contribution of electronic effect is greater than that of steric effect for the CO2 insertion into (PSiP)Pd-allyl bond; while for the phosphine substituent PMe2, the contribution of steric effect is slightly greater than that of electronic effect. PMID:25893517

Wang, Qin; Guo, Cai-Hong; Ren, Ying; Wu, Hai-Shun

2015-05-01

397

Structure-reactivity relationships in SHOP-type complexes: tunable catalysts for the oligomerisation and polymerisation of ethylene.  

PubMed

For over 30 years complexes with the general formula [NiPh(P,O)L] (L = tertiary phosphine; P,O = chelating phosphanylenolato ligand) have been used as highly efficient oligomerisation catalysts suitable for the production of linear alpha-olefins. The same complexes, which are usually referred to as SHOP-type catalysts (SHOP = Shell Higher Olefin Process) can also be used as ethylene polymerisation catalysts, provided they are treated with a phosphine scavenger that selectively removes the tertiary phosphine ligand (L). This Perspective examines the impact of various parameters (influence of the substituents, backbone size, solvent, use of co-catalysts, etc.) on the catalytic outcome of the complexes. Overall, this review shows that the selectivity and activity of the catalyst may be tuned efficiently through directed modification of the P,O chelator. PMID:17225902

Kuhn, Pierre; Sémeril, David; Matt, Dominique; Chetcuti, Michael J; Lutz, Pierre

2007-02-01

398

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

399

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

400

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

401

Synthesis and characterization of poly(ether ketone)s containing phosphorus and fluorine  

SciTech Connect

Because of the excellent properties exhibited by fluorinated poly(ether ketone)s, modifications were sought to further improve this polymer toward atomic oxygen resistance. For this purpose a phosphorous-containing monomer [bis(4-fluorophenyl)phenyl phosphine oxide] was synthesized and incorporated into a poly(ether ketone) backbone by reaction with 2,2-bis[4-(4-fluorobenzoyl)phenyl]hexafluoropropane in varying proportions with bisphenol AF to produce polymers with different amounts of the phosphine oxide repeating unit in the backbone. Colorless, film-forming materials were produced with a slight increase in Tg due to the phosphine oxide function. The incorporation of this moiety also resulted in a very small increase in the dielectric constant and an improved resistance to atomic oxygen ablation.

Youngman, P.W.; Fitch, J.W.; Cassidy, P.E. [Southwest Texas State Univ., San Marcos, TX (United States); [Langely Research Center, Hampton, VA (United States)

1996-10-01

402

New ruthenium nitrosyl pincer complexes bearing an o2 ligand. Mono-oxygen transfer.  

PubMed

We report on Ru((II))(?(2)-O2) nitrosyl pincer complexes that can return to their original Ru(0) state by reaction with mono-oxygen scavengers. Potential intermediates were calculated by density functional theory (DFT) and a mechanism is proposed, revealing a new type of metal-ligand cooperation consisting of activation of the O2 moiety by both the metal center and the NO ligand. Reaction of the Ru(0) nitrosyl complex 1 with O2 quantitatively yielded the crystallographically characterized Ru((II)) (?(2)-O2) nitrosyl complex 2. Reaction of 2 with the mono-oxygen scavengers phosphines or CO gave the Ru(0) complex 1 and phosphine oxides, or the carbonyl complex 3 (1 trapped by CO) and CO2, respectively. Reaction of 2 with 1 equiv of phosphine at room temperature or -40 °C resulted in immediate formation of half an equivalent of 1 and 1 equiv of phosphine oxide, while half an equivalent of 2 remained unchanged. Overnight reaction at room temperature of 2 with excess CO (?3 equiv) resulted in 3 and CO2 gas as the only products. Reaction of 1 with 1 equiv of mono-oxygen source (dioxirane) at -78 °C yielded the Ru((II))(?(2)-O2) complex 2. Similarly, reaction of the Ru(0) dearomatized complex 4 with O2 led to the crystallographicaly characterized Ru((II))(?(2)-O2) complex 5. Further reaction of 5 with mono-oxygen scavengers (phosphines or CO) led to the Ru(0) complex 4 and phosphine oxides or complex 6 (4 trapped by CO) and CO2. When instead only 1 equiv of 5 was reacted with 1 equiv of phosphine at room temperature, immediate formation of half an equivalent of 4 and 1 equiv of phosphine oxide took place, while half an equivalent of 5 remained unchanged. When 5 reacted with an excess of CO (?3 equiv), complex 6 and CO2 gas were the only products obtained. DFT studies indicate a new mode of metal-ligand cooperation involving the nitrosyl ligand in the oxygen transfer process. PMID:25695626

Fogler, Eran; Efremenko, Irena; Gargir, Moti; Leitus, Gregory; Diskin-Posner, Yael; Ben-David, Yehoshoa; Martin, Jan M L; Milstein, David

2015-03-01

403

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

PubMed Central

We have prepared the first examples of B9-connected trivalent aryl and alkyl phosphinoborane species via Pd-catalyzed phosphination of 9-iodo-meta-carborane. Our studies highlight the unique electronic features of the B9-connected meta-carboranyl moiety as compared to its C1-based analogue. This work suggests that the B9-functionalized meta-carboranyl substituent in these ligands exhibits more electron-releasing character than any other known carbon-based substituent, ultimately laying the foundation for a new class of phosphine ligands with extremely electron-rich character. PMID:23667288

Spokoyny, Alexander M.; Lewis, Calvin D.; Teverovskiy, Georgiy; Buchwald, Stephen L.

2012-01-01

404

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

405

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

406

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

407

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

408

Unusual activity pattern of leucine aminopeptidase inhibitors based on phosphorus containing derivatives of methionine and norleucine.  

PubMed

Ligands containing bulky aliphatic P1 residues exhibit a high affinity towards cytosolic leucine aminopeptidase, a bizinc protease of biomedical significance. According to this specificity, a series of phosphonic and phosphinic compounds have been put forward as novel putative inhibitors of the enzyme. These phosphonic and phosphinic compounds were derivatives of methionine and norleucine as both single amino acids and dipeptides. The designed inhibitors were synthesised and tested towards the peptidase isolated from porcine kidneys using an improved separation procedure affording superior homogeneity. Unexpectedly, organophosphorus derivatives of methionine and norleucine exhibited moderate activity with K(i) values in the micromolar range. PMID:20578976

Pícha, Jan; Liboska, Radek; Bud?šínský, Miloš; Jirá?ek, Ji?i; Pawe?czak, Ma?gorzata; Mucha, Artur

2011-04-01

409

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

410

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

411

Improved rhodium hydrogenation catalysts immobilized on silica? C. Merckle and J. Blu mel*  

E-print Network

Improved rhodium hydrogenation catalysts immobilized on silica? C. Merckle and J. Blu¨ mel Wilkinson-type rhodium catalysts with various mono and bidentate phosphine ligands have been synthesized group could function as linkers for immobilizing the rhodium complexes on silica and alumina. All

Bluemel, Janet

412

Department of Homeland Security Inventory DHS_inventory_form_revision_4_2011.doc Page 1 of 5  

E-print Network

-34-5 Boron trifluoride 7637-07-2 Carbonyl fluoride 353-50-4 Chlorine 7782-50-5 Chlorine dioxide 10049 bromide (anhydrous) 10035-10-6 Hydrogen chloride (anhydrous) 7647-01-0 Hydrogen fluoride (anhydrous) 7664 Quantity Units Oxygen difluoride 7783-41-7 Perchloryl fluoride 7616-94-6 Phosgene 75-44-5 Phosphine 7803

Pawlowski, Wojtek

413

This article was originally published in a journal published by Elsevier, and the attached copy is provided by Elsevier for the  

E-print Network

, and their structural nature [11c,11d]. Using our repertoire of different solid-state NMR techniques [10,11], we could, vulnera- ble to leaching [7c,11b]. This problem has been solved by using chelating linkers that prolong, immobilization, and solid-state NMR of new phosphine linkers with long alkyl chains Rachid Fetouaki, Annekathrin

Bluemel, Janet

414

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

E-print Network

limitedbydifficultiesinachievingindustriallyviablecatalyst-product separation.4 To solve this problem, many approaches have been explored, which can broadly the catalyst structure and its correlation to performance remain unclear. Multinuclear solid-state NMR Structure, Activity, and Stability of Triphenyl Phosphine-Modified Rh/SBA-15 Catalyst for Hydroformylation

Bao, Xinhe

415

Rational Ligand Design for the Arylation of Hindered Primary Amines Guided by Reaction Progress Kinetic Analysis  

PubMed Central

We report the Pd-catalyzed arylation of very hindered ?,?,?-trisubstituted primary amines. Kinetics-based mechanistic analysis and rational design have led to the development of two biaryl phosphine ligands that allow the transformation to proceed with excellent efficiency. The process was effective in coupling a wide range of functionalized aryl and heteroaryl halides under mild conditions. PMID:25651374

Ruiz-Castillo, Paula; Blackmond, Donna G.; Buchwald, Stephen L.

2015-01-01

416

The Influence of the Steric Effect of the Substituents on the Phosphorus Acids Dissociation  

Microsoft Academic Search

The dissociation processes of a series of phosphoric, phosphonic, and phosphinic acids have been studied by the modified method of potentiometry in water and water-ethanol media at 25°C. The influence of substituents on the acidic properties of these compounds has been investigated. As a measure of the substituents steric effects the Rs constants, calculated on the basis of frontal steric

V. I. Galkin; R. D. Sayakhov; A. R. Garifzyanov; V. F. Toropova; R. A. Cherkasov

1990-01-01

417

New ?-Functionalized Phosphorus Acid Surfactants: Synthesis, Dissociation Constants and Molecular Aggregation  

Microsoft Academic Search

Pursuing our investigation into h e reactivity of red phosphorus. its hydrolysis derivatives (PH3, and H3,PO2). and P-H labile compounds? we report here a convenient method for the direct synthesis of free a-hydroxyalkyl phosphinic acid surfactants from aqueous hypophosphorous acid and the long-chain aldehydes or imincs under sonication.

D. Albouy; A. Brun; G. Etemad-moghadam; A. Munoz; I. Rico-lattes

1999-01-01

418

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

419

40 CFR Ch. I (7105 Edition)Pt. 194 1,2,4-Trichlorobenzene (Benzene, 1,2,4-  

E-print Network

36 40 CFR Ch. I (7­1­05 Edition)Pt. 194 Toxaphene 1,2,4-Trichlorobenzene (Benzene, 1,2,4- trichloro (Benzene, 1,3,5-trinitro-) Tris(1-aziridinyl)phosphine sulfide (Aziridine, 1,1,1phosphinothioylidyne

420

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

421

DETECTION OF RHYZOPERTHA DOMINICA LARVAE IN STORED WHEAT USING ELISA: THE IMPACT OF MYOSIN DEGRADATION FOLLOWING FUMIGATION  

Technology Transfer Automated Retrieval System (TEKTRAN)

Hard red winter wheat kernels were infested with eggs of Rhyzopertha dominica. After 20 days, when the larvae reached the 4th instar, they were killed by exposing the grain to phosphine gas for 24 hours. The infested kernels were then divided into four portions and treated as follows: one portion wa...

422

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

423

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

424

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

425

Supporting Information Wiley-VCH 2008  

E-print Network

A Phosphine-Mediated Conversion of Azides to Diazo-Compounds Eddie L. Myers and Ronald T. Raines* Table of Triazene 10 with Carboxylic acid 11: Ester 12 S­20 4. Crystal Structure Determination of Acyl-Triazene 8 S were performed at room temperature (~23 °C) unless indicated otherwise. Reactions were monitored

Raines, Ronald T.

426

Chemical activation of molecules by metals: Experimental studies of electron distributions and bonding. Technical progress report, March 1, 1992February 28, 1995  

Microsoft Academic Search

During this period of the project we have (1) accomplished the high-resolution gas phase photoelectron spectra of C and C, (2) characterized the electronic features of imaging C on gold by STM, (3) evaluated the orbital distributions of C and the bonding interactions with metals, (4) revealed details of the bonding of phosphines to metals, including the subtleties of a

Lichtenberger

1997-01-01

427

Methanol triggered ligand flip isomerization in a binuclear copper(I) complex and the luminescence response.  

PubMed

Methanol drives the blue emissive complex, [Cu(2)(dppy)(3)(MeCN)](BF(4))(2) (dppy = diphenylphosphino-pyridine), with a head-to-tail arrangement of the three bridging phosphine ligands to convert to its linkage isomer (head-to-head, green emissive) in the solid state, and the transformation could be reversibly realized through recrystallization in different solvents. PMID:21761070

Li, Yang-Juan; Deng, Zhi-Ying; Xu, Xue-Fei; Wu, Hua-Bin; Cao, Ze-Xing; Wang, Quan-Ming

2011-08-28

428

Phosphorus-containing podands. Synthesis of neutral and acidic monopodands based on. cap alpha. -monophosphinylalkylated pyrocatechols  

SciTech Connect

Monopodands with phosphonate (neutral and acidic) and phosphine oxide terminal groups were obtained by the reaction of salts of mono-alpha-phosphinylalkylated pyrocatechols with oligoethylene glycols ditosylates and their analogs. A comprehensive chemical analysis of the reactions and their products, including hydrogen 1 and phosphorus 31 NMR spectra performed in a variety of deuterated solvents, is conducted.

Bovin, A.N.; Degtyarev, A.N.; Tsvetkov, E.N.

1987-06-20

429

Diastereospecific synthesis of phosphinidene-capped cyclodextrins leading to "introverted" ligands.  

PubMed

alpha-Cyclodextrins (alpha-CDs) containing "PPh" units which cap the primary face of the CD were obtained in high yield by reaction of Li(2)PPh with A,B- or A,C-dimesylated and A,B,D,E-tetramesylated precursors; the resulting phosphines are diastereomerically pure and constitute valuable precursors for the synthesis of metallo-cavitands. PMID:15010755

Engeldinger, Eric; Poorters, Laurent; Armspach, Dominique; Matt, Dominique; Toupet, Loïc

2004-03-21

430

40 CFR 721.10370 - Phosphonic acid, p-octyl-, lanthanum (3+) salt (2:1).  

Code of Federal Regulations, 2014 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...

2014-07-01

431

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

432

Directional Fe–C?O?S intermolecular interaction leading to chain-like crystal packing in binuclear Fe(0)–M(II) (M=Hg, Cd) complexes with 2-(diphenylphosphino)thiazole  

Microsoft Academic Search

A new thiazole-based phosphine ligand was designed to construct heterobinuclear complexes (CO)3Fe(?-Ph2PNS)2MX2 (M=Hg, X=SCN; M=Cd, X=I; Ph2PNS=2-(diphenylphosphino)thiazole), in which weak Fe–C?O?S intermolecular interaction led to chain-like molecular packing in the solid state.

Shan-Ming Kuang; Zheng-Zhi Zhang; Feng Xue; Thomas C. W. Mak

1999-01-01

433

Phosphorus chemistry on Titan  

NASA Astrophysics Data System (ADS)

Phosphorus is a key element in biology and acts in many critical biochemical functions. The chemistry of phosphorus in the outer Solar System has not yet been quantified, hence the astrobiological relevance of phosphorus to possible life on places like Titan is unconstrained. We evaluate phosphorus chemistry on Titan using a combination of modeling and laboratory techniques. We show that phosphorus chemistry on Titan consists of exogenous phosphates and reduced oxidation state phosphorus compounds, and accretionary phosphine. Accretionary phosphorus is shown to be delivered primarily by rocks and ices in the saturnian sub-nebula, and heating during accretion concentrates phosphine in the crust of Titan. The exogenous compounds are capable of performing biologically-relevant chemistry, however they are active only in environments with substantial liquid water, either pure, or as a mixture with NH 3 or nitrile compounds. In contrast, we show that phosphine is soluble in methane and ethane on Titan's surface, hence phosphine likely participates in the hydrocarbon cycle on Titan. The lack of mobility of phosphate compounds on Titan's surface suggests that if life is present on Titan, it must have a fundamentally different biochemistry than does terrestrial life.

Pasek, Matthew A.; Mousis, Olivier; Lunine, Jonathan I.

2011-04-01

434

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

435

Resolved P-metalated nucleoside phosphoramidites.  

PubMed

The synthesis of resolved P-metalated nucleoside phosphoramidites is described. These rare compounds were initially prepared with gold as the metal center; however, the gold can be removed using basic phosphines or solid-supported triphenylphosphine. Treatment of the free nucleoside phosphoramidite with a platinum source generated a unique platinated dinucleoside species with a diastereomeric ratio of >99:1. PMID:25437274

Miller, Erica J; Garcia, Kevin J; Holahan, Erin C; Ciccarelli, Rosa M; Bergin, Rachel A; Casino, Stephanie L; Bogaczyk, Tyler L; Krout, Michael R; Findeis, Peter M; Stockland, Robert A

2014-12-15

436

Synthesis of PEG-supported organotrifluoroborates and their applications in palladium-catalyzed homo-coupling reactions.  

PubMed

A general synthetic route to water-soluble PEG-supported organotrifluoroborates has been developed. In the presence of air and catalytic amounts of Pd(OAc)2, the PEG-supported organotrifluoroborates undergo homo-coupling reactions smoothly at room temperature. No additional oxidizing agent, base, or phosphine ligands are required. PMID:25665712

Yong, Li; Yao, Min-Liang; Blevins, David W; Kabalka, George W

2015-02-24

437

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.

438

Recent homogeneous catalytic applications of chelate and pincer N-heterocyclic carbenes  

Microsoft Academic Search

During the last decade, the use of N-heterocyclic carbene ligands (NHCs) based on imidazolium ions and related heterocycles has emerged as an alternative to phosphines in the design of new organometallic catalysts. We review catalysts with chelate and pincer NHC ligands, including complexes of palladium, ruthenium, rhodium and iridium. Transfer hydrogenation and Heck chemistry are given special attention. Also discussed

Eduardo Peris; Robert H Crabtree

2004-01-01

439

Domino hydroformylation/aldol condensation/hydrogenation catalysis: highly selective synthesis of ketones from olefins.  

PubMed

A general and highly chemo- and regioselective synthesis of ketones from olefins by domino hydroformylation/aldol condensation/hydrogenation reaction has been developed. A variety of olefins are efficiently converted into various ketones in good to excellent yields and regioselectivities in the presence of a specific rhodium phosphine/base-acid catalyst system. PMID:25331557

Fang, Xianjie; Jackstell, Ralf; Börner, Armin; Beller, Matthias

2014-11-24

440

Mechanism for the hydrolysis of organophosphates and investigations into the stereoselective hydrolysis of organophosphorus Esters by Phosphotriesterase.  

E-print Network

. The rate constants and stereoselectivity ratios for a number of active site mutants have been determined. H254Y/L303T PTE reverses the stereoselective preference of phosphonate and phosphinate substrates. The PTE stereoselectivity of O-methyl, O-phenyl...

Aubert, Sarah Dwyer

2006-04-12

441

Development of a novel multifunctional n,p ligand for highly enantioselective palladium-catalyzed asymmetric allylic etherification of alcohols and silanols.  

PubMed

CycloN2P2-Phos! The use of the multidentate phosphine, CycloN2P2-Phos, which contains four heteroatoms (two nitrogen and two phosphorus atoms), in the palladium-catalyzed asymmetric allylic etherification (AAE) of alcohols and silanols leads to excellent levels of enantioselectivity (up to 99?%?ee). PMID:24123352

Ye, Fei; Zheng, Zhan-Jiang; Li, Li; Yang, Ke-Fang; Xia, Chun-Gu; Xu, Li-Wen

2013-11-11

442

An alternative stereoselective synthesis of (R)- and (S)-Rosaphen® via asymmetric catalytic hydrogenation.  

PubMed

We report an alternative synthesis of the two enantiomers of the floral fragrance Rosaphen®. The key intermediate 2-methyl-5-phenylpentanoic acid 3 is synthesized via asymmetric hydrogenation (ee up to 99%) in the presence of an in situ prepared ruthenium catalyst containing the chiral ferrocenyl phosphine Mandyphos-4. PMID:22135807

Matteoli, Ugo; Beghetto, Valentina; Scrivanti, Alberto; Aversa, Manuela; Bertoldini, Matteo; Bovo, Sara

2011-10-01

443

Approved quarantine treatment for Hessian fly (Diptera: Cecidomyiidae) in large-size bales and Hessian fly and cereal leaf beetle (Coleoptera: Chrysomelidae) control by bale compression  

Technology Transfer Automated Retrieval System (TEKTRAN)

An approved quarantine treatment using bale compression (32 kg/sq cm of pressure) and phosphine fumigation (61 g/28.2 cu m) aluminum phosphide for 7 d at 20 degrees C) was determined to control Hessian fly, Mayetiola destructor (Say), in large-size, polypropylene fabric-wrapped bales exported from t...

444

Evidence for metal-ligand cooperation in a Pd-PNF pincer-catalyzed cross-coupling.  

PubMed

The first Pd-pincer complex bearing a halogen (fluorine) arm has been prepared via the base-assisted dearomatization of a phosphine-quinoline (P~N) ligand. This dearomatization is reversible and has been used to facilitate catalytic Sonogashira-type cross-coupling that, contrary to the typical mechanistic approach, is based on a metal-ligand cooperation mode. PMID:23256879

Scharf, Adam; Goldberg, Israel; Vigalok, Arkadi

2013-01-23

445

342nd Catalysis Research Center (CRC) Colloquium Quantum Simulation of the Reaction Mechanism of  

E-print Network

342nd Catalysis Research Center (CRC) Colloquium Quantum Simulation of the Reaction Mechanism of natural products. Two examples of computational study of organocatalysis will be presented. Our CRD method of allenoates and enones yields [3+2] cyclopentenes in phosphine catalysis, and [2+4] dihydropyrans or pyrans

Ishii, Hitoshi

446

Diastereo-and Enantioselective Alkylation of r-Imino Esters with Enol Silanes Catalyzed  

E-print Network

, catalytic, enantio- and diastereoselective alkyla- tions of carbonyl compounds.1 At the present time catalytic late-transition-metal phosphine complexes based on Ag(I), Cu(I), Ni(II), and Pd(II) (eq 1, R ) H which was converted to known compound 5 (eq 2).11 This methodology provides a conve- nient way

Lectka, Thomas

447

Efficient esterification of carboxylic acids and phosphonic acids with trialkyl orthoacetate in ionic liquid  

Microsoft Academic Search

An operationally simple, inexpensive, efficient, and environmentally friendly esterification of various carboxylic acids, phosphonic acids, and phosphinic acids with triethyl orthoacetate or trimethyl orthoacetate under neutral conditions in a typical room temperature ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate, was successfully carried out to provide the corresponding ethyl esters or methyl esters in high yields.

Tomonori Yoshino; Satomi Imori; Hideo Togo

2006-01-01

448

Highly Enantioselective Rhodium-Catalyzed Hydrogenation of  

E-print Network

been invented to facili- tate enantioselective catalytic reactions, and unique properties of chiralHighly Enantioselective Rhodium-Catalyzed Hydrogenation of Dehydroamino Acids with New Chiral is the key for the development of highly enantioselective reac- tions. In contrast to many chiral phosphines

Zhang, Xumu

449

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

450

Published: March 11, 2011 r 2011 American Chemical Society 4672 dx.doi.org/10.1021/ja110147w |J. Am. Chem. Soc. 2011, 133, 46724675  

E-print Network

of a Phosphine-Catalyzed [3 þ 2] Cycloaddition Reaction: Enantioselective Syntheses of Spirocyclopenteneoxindoles reaction.6 Thus, developing new, highly enantioselective methods for the direct construction of this skeleton is very important. In recent years, organocatalytic7 enantioselective domino/ cascade reactions8

Barbas III, Carlos F.

451

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

452

Mechanism-Based Triarylphosphine-Ester Probes for Capture of Endogenous RSNOs  

PubMed Central

Nitrosothiols (RSNOs) have been proposed as important intermediates in nitric oxide (NO•) metabolism, storage, and transport as well as mediators in numerous NO-signaling pathways. RSNO levels are finely regulated, and dysregulation is associated with the etiology of several pathologies. Current methods for RSNO quantification depend on indirect assays that limit their overall specificity and reliability. Recent developments of phosphine-based chemical probes constitute a promising approach for the direct detection of RSNOs. We report here results from a detailed mechanistic and kinetic study for trapping RSNOs by three distinct phosphine probes, including structural identification of novel intermediates and stability studies under physiological conditions. We further show that a triarylphosphine-thiophenyl ester can be used in the absolute quantification of endogenous GSNO in several cancer cell lines, while retaining the elements of the SNO functional group, using an LC–MS-based assay. Finally, we demonstrate that a common product ion (m/z = 309.0), derived from phosphine–RSNO adducts, can be used for the detection of other low-molecular weight nitrosothiols (LMW-RSNOs) in biological samples. Collectively, these findings establish a platform for the phosphine ligation-based, specific and direct detection of RSNOs in biological samples, a powerful tool for expanding the knowledge of the biology and chemistry of NO•-mediated phenomena. PMID:23614769

2013-01-01

453

40 CFR Appendix IV to Part 266 - Reference Air Concentrations*  

Code of Federal Regulations, 2010 CFR

...79-22-1 1000 Methyl Ethyl Ketone 78-93-3 80...Pentachlorophenol 87-86-5 30 Phenol 108-95-2 30 M-Phenylenediamine...108-45-2 5 Phenylmercuric Acetate 62-38-4 0.075 Phosphine...7440-28-0 0.5 Thallium (I) Acetate 563-68-8 0.5...

2010-07-01

454

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

455

In-depth survey report of Early and Daniel Co. , Inc. , Louisville, Kentucky  

Microsoft Academic Search

An in-depth industrial hygiene survey was conducted to evaluate worker exposures to phosphine during fumigation of grain at the Early and Daniel Co. grain elevator in Louisville, Kentucky. Stored grain was fumigated using aluminum phosphide. Aluminum-phosphide pellets were also added directly to the grain by the blender as it was poured into the storage containers. Local exhaust ventilation was used

Zaebst

1986-01-01

456

Unfolding and Refolding of Aspergillus Niger PhyB Phytase: Role of Disulfide Bridges  

Technology Transfer Automated Retrieval System (TEKTRAN)

Role of disulfide bridges in folding of Aspergillus niger phytase pH 2.5-optimum (PhyB) was investigated using dynamic light scattering (DLS). Guanidinium chloride (GuCl) at 1.0 M unfolded phytase; however, its removal by dialysis refolded the protein. Thiol reagent, tris (2-carboxyethyl) phosphin...

457

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

458

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...

459

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

460

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

461

Synthesis and application of pyridine-based ambipolar hosts: control of charge balance in organic light emitting devices (OLEDs) by chemical structure modification  

SciTech Connect

Pyridine-based host materials were synthesized via Grignard metathesis of bromopyridines to provide the required organometallic reagent. The isomeric hosts (4-(9H-carbazol-9-yl)phenyl)(phenyl)(pyridin-3-yl)phosphine oxide (HM-A4), (5-(9H-carbazol-9-yl)pyridin-2-yl)diphenylphosphine oxide (HM-A5), and (5-(diphenylamino)pyridin-2-yl)diphenylphosphine oxide (HM-A6), (4-(diphenylamino)phenyl)(phenyl)(pyridin-3-yl)phosphine oxide (HM-A8) have similar frontier orbital energies. Organic light emitting devices (OLEDs) fabricated using the series of the host materials demonstrate that small structural modification of the host results in significant change in charge transporting ability.

Koech, Phillip K.; Polikarpov, Evgueni; Rainbolt, James E.; Cosimbescu, Lelia; Swensen, James S.; Von Ruden, Amber L.; Padmaperuma, Asanga B.

2010-11-05

462

Carbons and hydrogen by persistent metal radicals. Final report, April 1, 1993--October 31, 1994  

SciTech Connect

The synthesis of complexed rhenium radicals is demonstrated from the reaction of sterically demanding phosphine with the triphenylmethyl complex [n{sup 5}-CPh{sub 3}]Re(CO){sub 3}. Low yields are experienced unless high concentrations of phosphine ligands are employed with the mechanism of this reaction yet unknown. A complexed rhenium dimer is also synthesized, but in low yield. X-ray crystallography reveals that the sixth coordination site of the electron deficient rhenium cation (an extremely strong Lewis acid) is occupied by an agostic interaction with one of the pendant C-H bonds of the cyclohexyl ring of the complex. Preliminary results show that the rhenium complexes have a significantly different chemistry from similar tungsten analogs in reactivity and isotope exchange rates. It is hypothesized that the rhenium complexes would be useful in catalyzing the isotope exchange between water and hydrogen.

Not Available

1995-12-31

463

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

464

Aromatic amide-derived non-biaryl atropisomers as highly efficient ligands in silver-catalyzed asymmetric cycloaddition reactions.  

PubMed

The synthesis of a series of aromatic amide-derived non-biaryl atropisomers with a phosphine group and multiple stereogenic centers is reported. The novel phosphine ligands exhibit high diastereo- and enantioselectivities (up to >99:1 d.r., 95-99?% ee) as well as yields in the silver-catalyzed asymmetric [3+2] cycloaddition of aldiminoesters with nitroalkenes, which provides a highly enantioselective strategy for the synthesis of optically pure nitro-substituted pyrrolidines. In addition, the experimental results with regard to the carbon stereogenic center as well as the amide stereochemistry confirmed the potential of hemilabile atropisomers as chiral ligand in catalytic asymmetric [3+2] cycloaddition reaction. PMID:25728216

Bai, Xing-Feng; Song, Tao; Xu, Zheng; Xia, Chun-Gu; Huang, Wei-Sheng; Xu, Li-Wen

2015-04-20

465

Room temperature asymmetric Pd-catalyzed methoxycarbonylation of norbornene: highly selective catalysis and HP-NMR studies.  

PubMed

Palladium complexes bearing monodentate and bidentate phosphine ligands (1-7) were synthesised and used as catalyst precursors in the methoxycarbonylation of norbornene. The catalytic systems bearing ligands 1, 3 and 4 afforded excellent conversions (>99%) and selectivity of the ester (>99%). NMR investigations showed that using complex 1a as the precursor resulted in the protonated phosphine, 1-H(+), being formed under catalytic conditions and thus the addition of acid is not required for the activation of this system since the reaction involving the precursor with methanol under CO pressure produces 2 equivalents of HCl and leads to the formation of the active species. The protonation of ligand 4 under methoxycarbonylation conditions was also observed and the diprotonated diphosphine was isolated and characterised. This compound was tested as a ligand and acid source in a catalysis and provided excellent conversion and high selectivity to the ester. PMID:22535338

Blanco, Carolina; Godard, Cyril; Zangrando, Ennio; Ruiz, Aurora; Claver, Carmen

2012-06-21

466

A 27.3-percent efficient Ga(0.5)In(0.5)P/GaAs tandem solar cell  

NASA Astrophysics Data System (ADS)

A two-terminal, monolithic cascade solar cell with an efficiency of 27.3 percent is reported. The device structure consists of a Ga(0.5)In(0.5)P homojunction grown epitaxially upon a GaAs homojunction, with a GaAs tunnel diode interconnect. The tandem combination of these two materials is lattice matched, and has a theoretical efficiency of 34 percent. The device was grown by metalorganic chemical vapor deposition at 700 C, using trimethylgallium, trimethylindium, arsine, and phosphine as sources. The minority-carrier transport properties of the Ga(0.5)In(0.5)P are shown to be relatively insensitive to variations of the growth temperature and phosphine overpressure. Other factors that affect the efficiency of the device are presented and discussed.

Olson, J. M.; Kurtz, S. R.; Kibbler, A. E.; Faine, P.

1990-02-01

467

A 27. 3% efficient Ga sub 0. 5 In sub 0. 5 P/GaAs tandem solar cell  

SciTech Connect

A two-terminal, monolithic cascade solar cell with an efficiency of 27.3% is reported. The device structure consists of a Ga{sub 0.5}In{sub 0.5}P homojunction grown epitaxially upon a GaAs homojunction, with a GaAs tunnel diode interconnect. The tandem combination of these two materials is lattice matched, and has a theoretical efficiency of 34%. The device was grown by metalorganic chemical vapor deposition at 700 {degree}C, using trimethylgallium, trimethylindium, arsine, and phosphine as sources. The minority-carrier transport properties of the Ga{sub 0.5}In{sub 0.5}P are shown to be relatively insensitive to variations of the growth temperature and phosphine overpressure. Other factors that affect the efficiency of the device are presented and discussed.

Olson, J.M.; Kurtz, S.R.; Kibbler, A.E.; Faine, P. (Solar Energy Research Institute, Golden, Colorado 80401 (US))

1990-02-12

468

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

469

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

470

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

471

Alternatives to methyl bromide treatments for stored-product and quarantine insects.  

PubMed

Methyl bromide is used to control insects as a space fumigant in flour and feed mills and ship holds, as a product fumigant for some fruit and cereals, and for general quarantine purposes. Methyl bromide acts rapidly, controlling insects in less than 48 h in space fumigations, and it has a wide spectrum of activity, controlling not only insects but also nematodes and plant-pathogenic microbes. This chemical will be banned in 2005 in developed countries, except for exceptional quarantine purposes, because it depletes ozone in the atmosphere. Many alternatives have been tested as replacements for methyl bromide, from physical control methods such as heat, cold, and sanitation to fumigant replacements such as phosphine, sulfuryl fluoride, and carbonyl sulfide, among others. Individual situations will require their own type of pest control techniques, but the most promising include integrated pest management tactics and combinations of treatments such as phosphine, carbon dioxide, and heat. PMID:11729078

Fields, Paul G; White, Noel D G

2002-01-01

472

Synthetic and Thermodynamic Investigations of Ancillary Ligand Influence on Catalytic Organometallic Systems. Final Report  

SciTech Connect

During the grant period we have been involved in synthesizing and experimentally determining solution enthalpy values associated with partially fluorinated ligands. This has lead to the publication of manuscripts dealing with synthetic, calorimetric and catalytic behavior of partially fluorinated ligands. The collaboration with Los Alamos researchers has lead to the publication of catalytic results in sc CO{sub 2} which have proven very interesting. Furthermore, we have also examined ligands that behave as phosphine mimics. The N-heterocyclic carbenes have been explored as alternatives for tertiary phosphines and have resulted in the design and construction of efficient palladium and nickel system capable of performing C-C and C-N cross coupling reactions. The initial studies in this areas were made possible by exploratory work conducted under the DOE/EPSCoR grant.

Nolan, Steven

2003-03-20

473

Temperature- and voltage-induced ligand rearrangement of a dynamic electroluminescent metallopolymer.  

PubMed

A dynamic-covalent metal-containing polymer was synthesized by the condensation of linear diamine and dialdehyde subcomponents around copper(I) templates in the presence of bidentate phosphine ligands. In solution, the red polymers undergo a sol-gel transition upon heating to form a yellow gel, a process that can be either reversible or irreversible depending on the solvent used. When fabricated into a light-emitting electrochemical cell (LEC), the polymer emits infrared light at low voltage. As the voltage is increased, a blue shift in the emission wavelength is observed until yellow light is emitted, a process which is gradually reversed over time upon lowering the voltage. The mechanism underlying these apparently disparate responses is deduced to be due to loss of the copper phosphine complex from the polymer. PMID:24962081

Asil, Demet; Foster, Jonathan A; Patra, Asit; de Hatten, Xavier; del Barrio, Jesús; Scherman, Oren A; Nitschke, Jonathan R; Friend, Richard H

2014-08-01

474

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

475

Extracting metals directly from metal oxides  

DOEpatents

A method of extracting metals directly from metal oxides by exposing the oxide to a supercritical fluid solvent containing a chelating agent is described. Preferably, the metal is an actinide or a lanthanide. More preferably, the metal is uranium, thorium or plutonium. The chelating agent forms chelates that are soluble in the supercritical fluid, thereby allowing direct removal of the metal from the metal oxide. In preferred embodiments, the extraction solvent is supercritical carbon dioxide and the chelating agent is selected from the group consisting of {beta}-diketones, halogenated {beta}-diketones, phosphinic acids, halogenated phosphinic acids, carboxylic acids, halogenated carboxylic acids, and mixtures thereof. In especially preferred embodiments, at least one of the chelating agents is fluorinated. The method provides an environmentally benign process for removing metals from metal oxides without using acids or biologically harmful solvents. The chelate and supercritical fluid can be regenerated, and the metal recovered, to provide an economic, efficient process. 4 figs.

Wai, C.M.; Smart, N.G.; Phelps, C.

1997-02-25

476

Extracting metals directly from metal oxides  

DOEpatents

A method of extracting metals directly from metal oxides by exposing the oxide to a supercritical fluid solvent containing a chelating agent is described. Preferably, the metal is an actinide or a lanthanide. More preferably, the metal is uranium, thorium or plutonium. The chelating agent forms chelates that are soluble in the supercritical fluid, thereby allowing direct removal of the metal from the metal oxide. In preferred embodiments, the extraction solvent is supercritical carbon dioxide and the chelating agent is selected from the group consisting of .beta.-diketones, halogenated .beta.-diketones, phosphinic acids, halogenated phosphinic acids, carboxylic acids, halogenated carboxylic acids, and mixtures thereof. In especially preferred embodiments, at least one of the chelating agents is fluorinated. The method provides an environmentally benign process for removing metals from metal oxides without using acids or biologically harmful solvents. The chelate and supercritical fluid can be regenerated, and the metal recovered, to provide an economic, efficient process.

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

1997-01-01

477

Reactivity of Metal Ions Bound to Water-Soluble Polymers  

SciTech Connect

The intent of this work is to determine the effectiveness of catalysts covalently bound to polymers and to understand the consequences of supporting the catalysts on catalyst efficiency and selectivity. Rhodium phosphine complexes with functional groups for coupling to polymers were prepared. These catalyst precursors were characterized using standard techniques including IR, NMR, and elemental analysis. Studies on the modified catalysts showed that they were still active hydrogenation catalysts. However, tethering of the catalysts to polyamines gave systems with low hydrogenation activity. Analogous biphasic systems were also explored. Phosphine ligands with a surfactant-like structure have been synthesized and used to prepare catalytically active complexes of palladium. The palladium complexes were utilized in Heck-type coupling reactions (e.g. coupling of iodobenzene and ethyl acrylate to produce ethyl cinnamate) under vigorously stirred biphasic reaction conditions, and were found to offer superior performance over a standard water-soluble palladium catalyst under analogous conditions.

Sauer, N.N.; Watkins, J.G.; Lin, M.; Birnbaum, E.R.; Robison, T.W.; Smith, B.F.; Gohdes, J.W.; McDonald, J.G.

1999-06-29

478

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,