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Sample records for phosphines

  1. Phosphine

    Integrated Risk Information System (IRIS)

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

  2. Mechanisms of Phosphine Toxicity

    PubMed Central

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

    2011-01-01

    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

  3. CONFIRMATION OF CIRCUMSTELLAR PHOSPHINE

    SciTech Connect

    Agúndez, M.; Cernicharo, J.; Encrenaz, P.; Teyssier, D.

    2014-08-01

    Phosphine (PH{sub 3}) was tentatively identified a few years ago in the carbon star envelopes IRC +10216 and CRL 2688 from observations of an emission line at 266.9 GHz attributable to the J = 1-0 rotational transition. We report the detection of the J = 2-1 rotational transition of PH{sub 3} in IRC +10216 using the HIFI instrument on board Herschel, which definitively confirms the identification of PH{sub 3}. Radiative transfer calculations indicate that infrared pumping in excited vibrational states plays an important role in the excitation of PH{sub 3} in the envelope of IRC +10216, and that the observed lines are consistent with phosphine being formed anywhere between the star and 100 R {sub *} from the star, with an abundance of 10{sup –8} relative to H{sub 2}. The detection of PH{sub 3} challenges chemical models, none of which offer a satisfactory formation scenario. Although PH{sub 3} holds just 2% of the total available phosphorus in IRC +10216, it is, together with HCP, one of the major gas phase carriers of phosphorus in the inner circumstellar layers, suggesting that it could also be an important phosphorus species in other astronomical environments. This is the first unambiguous detection of PH{sub 3} outside the solar system, and is a further step toward a better understanding of the chemistry of phosphorus in space.

  4. 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. Chiral phosphines in nucleophilic organocatalysis

    PubMed Central

    Xiao, Yumei; Sun, Zhanhu

    2014-01-01

    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

  6. Reductive Catenation of Phosphine Antimony Complexes.

    PubMed

    Chitnis, Saurabh S; Burford, Neil; Weigand, Jan J; McDonald, Robert

    2015-06-26

    Reactions of triarylphosphines with fluoroantimony(III) triflates give phosphine antimony(III) complexes, which undergo spontaneous reductive elimination of fluorophosphonium cations. The resulting phosphine antimony(I) complexes catenate to give the first examples of cationic antimony bicyclic compounds, [(R3P)4Sb6](4+), featuring a bicyclo[3.1.0]hexastibine framework stabilized by four phosphine ligands. The unprecedented 14-electron redox process illustrates the generality of the reductive catenation method. PMID:26037929

  7. Matrix-bound phosphine in Antarctic biosphere.

    PubMed

    Zhu, Renbin; Sun, Liguang; Kong, Deming; Geng, Jinju; Wang, Ning; Wang, Qiang; Wang, Xiaorong

    2006-08-01

    Phosphine (PH(3)) is a natural gaseous carrier of phosphorus in its geochemical cycles, and it might be of importance to the phosphorus balance of natural ecosystem. For the first time phosphine levels were investigated in the Earth's coldest, driest, and most southerly Antarctic biosphere. Matrix-bound phosphine (MBP) was found in sea animal guanos, ornithogenic sediments and soils. Phosphine concentrations varied with different sea animal guanos. Average phosphine concentrations in empire penguin, gentoo penguin, sea lion, skua and gull guanos were 2.54+/-1.28 ng kg(-1), 6.21+/-2.15 ng kg(-1), 9.12+/-4.66 ng kg(-1), 11.90+/-1.29 ng kg(-1) and 14.55+/-6.74 ng kg(-1), respectively. The contents of phosphorus in these various matrixes have an important effect on MBP concentrations. The levels of phosphine appeared an increasing tendency with the content of TP, IP and OP in sea animal guanos, ornithogenic sediments or soils. The correlation between PH(3) and Fe, Mn, Al in these matrixes was also analyzed and discussed. Phosphine showed an obviously positive correlation with Fe in sea animal guanos. However, excessively high Fe, Al and Mn may inhibit the formation of PH(3) in the ornithogenic soils or sediments in the Antarctic biosphere. PMID:16504242

  8. Phosphine photochemistry in Saturn's atmosphere

    NASA Technical Reports Server (NTRS)

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

    1983-01-01

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

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

    Code of Federal Regulations, 2010 CFR

    2010-07-01

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

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

    PubMed

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

    2012-02-17

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

  11. Phosphine from rocks: mechanically driven phosphate reduction?

    PubMed

    Glindemann, Dietmar; Edwards, Marc; Morgenstern, Peter

    2005-11-01

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

  12. 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...

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

    E-print Network

    Jones, William D.

    Catalytic Hydrogenolysis of Biphenylene with Platinum, Palladium, and Nickel Phosphine Complexes activation and formation by plati- num and palladium phosphine complexes.4g The oper- ating catalytic cycle

  14. Homo- and Heteropolynuclear Clusters of Phosphine Triphenolates.

    PubMed

    Liang, Lan-Chang; Chou, Kuan-Wei; Su, Wei-Jia; Chen, Han-Sheng; Hsu, Yu-Lin

    2015-12-01

    The synthesis and structural characterization of a series of homo- and heteropolynuclear clusters constructed with a potentially tetradentate phosphine triphenolate ligand are presented. Treatment of tris(3,5-di-tert-butyl-2-hydroxyphenyl)phosphine (H3[O3P]) with 3 equiv of nBuLi in diethyl ether at -35 °C affords hexanuclear Li6[O3P]2(OEt2)2 (1) as colorless crystals. In situ lithiation of H3[O3P] with 3 equiv of nBuLi in THF at -35 °C followed by metathetical reactions with MnCl2 or NiCl2(DME) gives crystals of forest green pentanuclear MnLi4[O3P]2(THF)3 (2) or dark brown tetranuclear Ni2Li2[O3P]2(THF)2 (3), respectively. Alkane elimination of ZnR2 (R = Me, Et) with H3[O3P] in THF at 25 °C generates high yields of colorless crystalline trinuclear Zn3[O3P]2(THF)2 (4). The cluster structures of 1-4 were all determined by single crystal X-ray diffraction studies. These molecules represent the first examples of metal complexes supported by phosphine triphenolate derivatives. The cluster 2 contains a paramagnetic core of high spin Mn(II) (S = 5/2) as indicated by solution and solid state magnetic susceptibility measurements. PMID:26587884

  15. Perfluoropropenyl-containing phosphines from HFC replacements.

    PubMed

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

    2015-12-01

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

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

    E-print Network

    Hammock, Bruce D.

    decades (Chaudhry et al., 2004). Phosphine has a range of physical and chemical properties that make, whereas there is no change in the level of ferritin-2. This resembles the reported pattern of ferritin). The possible role of hydrogen peroxide in phosphine toxicity was elaborated in a recent chemical model in which

  17. Preparation of phosphines through C–P bond formation

    PubMed Central

    Wauters, Iris; Debrouwer, Wouter

    2014-01-01

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

  18. 7 CFR 305.7 - Phosphine treatment schedules.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 5 2010-01-01 2010-01-01 false Phosphine treatment schedules. 305.7 Section 305.7 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE PHYTOSANITARY TREATMENTS Chemical Treatments § 305.7 Phosphine treatment schedules. Treatmentschedule...

  19. Phosphine production potential of various wastewater and sewage sludge sources

    SciTech Connect

    Devai, I.; DeLaune, R.D.; Patrick, W.H. Jr.; Devai, G.; Czegeny, I.

    1999-05-01

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

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

    PubMed Central

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

    2012-01-01

    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

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

    PubMed

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

    2013-11-01

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

  2. Mitsunobu Reactions Catalytic in Phosphine and a Fully Catalytic System.

    PubMed

    Buonomo, Joseph A; Aldrich, Courtney C

    2015-10-26

    The Mitsunobu reaction is renowned for its mild reaction conditions and broad substrate tolerance, but has limited utility in process chemistry and industrial applications due to poor atom economy and the generation of stoichiometric phosphine oxide and hydrazine by-products that complicate purification. A catalytic Mitsunobu reaction using innocuous reagents to recycle these by-products would overcome both of these shortcomings. Herein we report a protocol that is catalytic in phosphine (1-phenylphospholane) employing phenylsilane to recycle the catalyst. Integration of this phosphine catalytic cycle with Taniguchi's azocarboxylate catalytic system provided the first fully catalytic Mitsunobu reaction. PMID:26347115

  3. Mitsunobu Reactions Catalytic in Phosphine and a Fully Catalytic System

    PubMed Central

    Buonomo, Joseph A; Aldrich, Courtney C

    2015-01-01

    The Mitsunobu reaction is renowned for its mild reaction conditions and broad substrate tolerance, but has limited utility in process chemistry and industrial applications due to poor atom economy and the generation of stoichiometric phosphine oxide and hydrazine by-products that complicate purification. A catalytic Mitsunobu reaction using innocuous reagents to recycle these by-products would overcome both of these shortcomings. Herein we report a protocol that is catalytic in phosphine (1-phenylphospholane) employing phenylsilane to recycle the catalyst. Integration of this phosphine catalytic cycle with Taniguchi’s azocarboxylate catalytic system provided the first fully catalytic Mitsunobu reaction. PMID:26347115

  4. Dialkylbiaryl phosphines in Pd-catalyzed amination: a user's guide

    E-print Network

    Surry, David S.

    Dialkylbiaryl phosphines are a valuable class of ligand for Pd-catalyzed amination reactions and have been applied in a range of contexts. This perspective attempts to aid the reader in the selection of the best choice of ...

  5. Hydroxyalkyl phosphine compounds for use as diagnostic and therapeutic pharmaceuticals

    DOEpatents

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

    1999-03-02

    This research discloses a compound and method of making a compound for use as a diagnostic or therapeutic pharmaceutical comprises a functionalized hydroxyalkyl phosphine ligand and a metal combined with the ligand. 16 figs.

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

    Code of Federal Regulations, 2013 CFR

    2013-07-01

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

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

    Code of Federal Regulations, 2011 CFR

    2011-07-01

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

  8. 40 CFR 721.10135 - Phosphinic acid, P,P-diethyl-, zinc salt (2:1).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

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

  9. 40 CFR 721.10135 - Phosphinic acid, P,P-diethyl-, zinc salt (2:1).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

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

  10. 40 CFR 721.10135 - Phosphinic acid, P,P-diethyl-, zinc salt (2:1).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

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

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

    PubMed Central

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

    2013-01-01

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

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

    PubMed

    Lloyd-Jones, Guy C; Taylor, Nicholas P

    2015-03-27

    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

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

    PubMed Central

    Shapiro, Nathan D.; Toste, F. Dean

    2008-01-01

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

  14. 40 CFR 180.225 - Phosphine; tolerances for residues.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

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

  15. 40 CFR 180.225 - Phosphine; tolerances for residues.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

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

  16. 40 CFR 180.225 - Phosphine; tolerances for residues.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

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

  17. 40 CFR 180.225 - Phosphine; tolerances for residues.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

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

  18. Formation of Phenylene Oligomers Using Platinum-Phosphine Complexes

    E-print Network

    Jones, William D.

    Formation of Phenylene Oligomers Using Platinum-Phosphine Complexes Nira Simhai, Carl N. Iverson, New York 14627 Received February 12, 2001 The reaction of biphenylene with a series of platinum bis to tetraphenylene using a platinum phos- phine catalyst (eq 2),8 and Ni(COD)(PMe3)2 has also (1) Topics

  19. Resistance of Lasioderma serricorne (Coleoptera: Anobiidae) to Fumigation with Phosphine.

    PubMed

    Sa?lam, Özgür; Edde, Peter A; Phillips, Thomas W

    2015-10-01

    Lasioderma serricorne (F.) is a serious pest of stored products that is known to be resistant to the fumigant pesticide gas phosphine. This study investigated resistance in populations from the southeastern United States, and determined if a recommended treatment schedule could kill resistant insects. A laboratory assay for adult insects was developed that used a discriminating concentration of 50 ppm phosphine applied to insects for 20 h at 25°C followed by 7 d of recovery in air. Survivors were classified as resistant. L. serricorne from six different field populations associated with stored tobacco were surveyed with the assay and all had resistant individuals. Four populations had greater than 90% of their insects resistant. Two industry-recommended treatment schedules were evaluated in laboratory fumigations against mixed life stage cultures of the four most resistant populations: the first at 200 ppm for 4 d at 25°C for controlling phosphine-susceptible L. serricorne and the second at 600 ppm for 6 d at 25°C intended to control phosphine-resistant beetles. The four populations with the highest frequency of resistant individuals from the field sampling study were not controlled by the "normal" treatment intended for susceptible insects. The higher concentration treatment greatly reduced beetle progeny from mixed-stage colony jars, but there were substantial numbers of surviving adults from all four highly resistant populations that represented unacceptable levels of control. PMID:26453739

  20. Tropospheric phosphine and its sources in coastal antarctica.

    PubMed

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

    2006-12-15

    Earlier reports show very low concentrations of phosphine in remote air of the lower troposphere of nonpolar regions, in the low ng m(-3) range during the night and in the pg m(-3) range during daylight around noon. In this study, abnormally and unexpectedly high phosphine concentrations (30.0-407.8 ng m(-3), 11 locations) were found in polar air samples collected on Millor Peninsula, eastern Antarctica and Fildes Peninsula, western Antarctica. The maximum concentration was measured in the atmosphere of penguin colonies. Field phosphine emission rates from four colonies were 8.99 ng m(-2) h(-1) (skua colony), 9.56 ng m(-2) h(-1) (gentoo penguin colony), 39.96 ng m-2 h-' (seal colony) and 63.58 ng m(-2) h(-1) (empire penguin colony), respectively. Our air sampling sites are located downwind of two large penguin colonies, indicating that penguin colony emission is the predominant source for atmospheric PH3 on Millor Peninsula. Laboratory scale incubation of ornithogenic soils amended by penguin guanos yielded a maximum PH3 production rate of 0.58 ng kg(-1) d(-1) specifically at low temperature (4 degrees C). Significant concentrations of phosphine occur in the atmosphere of coastal Antarctica and confirm the existence of a small gaseous link in the phosphorus cycle of the Antarctic tundra ecosystem. PMID:17256509

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

    PubMed Central

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

    2015-01-01

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

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

    PubMed

    Copey, Laurent; Jean-Gérard, Ludivine; Framery, Eric; Pilet, Guillaume; Robert, Vincent; Andrioletti, Bruno

    2015-06-15

    An efficient enantioselective strategy for the synthesis of variously substituted phosphine oxides has been developed, incorporating the use of (1S,2S)-2-aminocyclohexanol as the chiral auxiliary. The method relies on three key steps: 1)?Highly diastereoselective formation of P(V) oxazaphospholidine, rationalized by a theoretical study; 2)?highly diastereoselective ring-opening of the oxazaphospholidine oxide with organometallic reagents that takes place with inversion of configuration at the P atom; 3)?enantioselective synthesis of phosphine oxides by cleavage of the remaining P-O bond. Interestingly, the use of a P(III) phosphine precursor afforded a P-epimer oxazaphospholidine. Hence, the two enantiomeric phosphine oxides can be synthesized starting from either a P(V) or a P(III) phosphine precursor, which constitutes a clear advantage for the stereoselective synthesis of sterically hindered phosphine oxides. PMID:25980800

  3. Phosphine Gas Adsorption in a Series of Metal-Organic Frameworks.

    PubMed

    Weston, Mitchell H; Morris, William; Siu, Paul W; Hoover, William J; Cho, David; Richardson, Rachelle K; Farha, Omar K

    2015-09-01

    For the first time, phosphine adsorption has been evaluated in a series of metal-organic frameworks (MOFs). Open-metal coordination sites were found to significantly enhance the ability of MOFs to adsorb highly toxic phosphine gas, with the identity of the open-metal site also modulating the amount of gas adsorbed. The MOFs studied outperform activated carbon, a commonly used material to capture phosphine. PMID:26274578

  4. Action of phosphine on production of aflatoxins by various Aspergillus strains isolated from foodstuffs.

    PubMed Central

    Leitao, J; de Saint-Blanquat, G; Bailly, J R

    1987-01-01

    Phosphine is a food fumigant, used until now as an insecticide and rodenticide. The present work researches the action of phosphine treatment on growth and aflatoxin production of 23 Aspergillus strains. Production of aflatoxins B1, B2, G1, and G2 decreased in almost all cases by a ratio of 10 to 100. Phosphine treatment therefore seems favorable to prevent growth of various Aspergillus strains, in the context of keeping food safe. PMID:3426212

  5. Rhodium catalysed hydroformylation of alkenes using highly fluorophilic phosphines.

    PubMed

    Adams, Dave J; Bennett, James A; Cole-Hamilton, David J; Hope, Eric G; Hopewell, Jonathan; Kight, Jo; Pogorzelec, Peter; Stuart, Alison M

    2005-12-21

    Highly fluorophilic phosphines incorporating at least one aromatic ring containing two directly attached perfluoroalkyl groups have been synthesised, their partition coefficients (organic phase : fluorous phase) measured and their electronic properties probed using (1)J(PtP) data for their trans-[PtCl(2)L(2)] complexes. These phosphines have been used as modifying ligands for the rhodium catalysed hydroformylation of 1-octene in perfluorocarbon solvents. Catalyst activity, regioselectivity and the levels of rhodium leaching to the product phase vary with the substitution patterns of the modifying ligands that do not correlate with the electronic properties or partition coefficients of these ligands, but can be interpreted in terms of differences in the resting states of the catalysts. PMID:16311639

  6. Oxygen plasma resistant phosphine oxide containing imide/arylene copolymers

    NASA Technical Reports Server (NTRS)

    Jensen, Brian J.

    1993-01-01

    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.

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

    PubMed Central

    Fan, Yi Chiao

    2014-01-01

    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

  8. Biaryl Phosphine Ligands in Palladium-Catalyzed Amination

    PubMed Central

    Surry, David S.

    2012-01-01

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

  9. Retrievals of Jovian Tropospheric Phosphine from Cassini/CIRS

    NASA Technical Reports Server (NTRS)

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

    2004-01-01

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

  10. Structural, spectroscopic and computational examination of the dative interaction in constrained phosphine-stibines and phosphine-stiboranes.

    PubMed

    Chalmers, Brian A; Bühl, Michael; Athukorala Arachchige, Kasun S; Slawin, Alexandra M Z; Kilian, Petr

    2015-05-11

    A series of phosphine-stibine and phosphine-stiborane peri-substituted acenaphthenes containing all permutations of pentavalent groups -SbCln Ph4-n (5-9), as well as trivalent groups -SbCl2 , -Sb(R)Cl, and -SbPh2 (2-4, R=Ph, Mes), were synthesised and fully characterised by single crystal diffraction and multinuclear NMR spectroscopy. In addition, the bonding in these species was studied by DFT computational methods. The P-Sb dative interactions in both series range from strongly bonding to non-bonding as the Lewis acidity of the Sb acceptor is decreased. In the pentavalent antimony series, a significant change in the P-Sb distance is observed between -SbClPh3 and -SbCl2 Ph2 derivatives 6 and 7, respectively, consistent with a change from a bonding to a non-bonding interaction in response to relatively small modification in Lewis acidity of the acceptor. In the Sb(III) series, two geometric forms are observed. The P-Sb bond length in the SbCl2 derivative 2 is as expected for a normal (rather than a dative) bond. Rather unexpectedly, the phosphine-stiborane complexes 5-9 represent the first examples of the ?(4) P??(6) Sb structural motif. PMID:25820876

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

    ERIC Educational Resources Information Center

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

    2007-01-01

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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  13. 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...

  14. P-Arylation of Dialkyl Phosphites and Secondary Phosphine Oxides with Arynes.

    PubMed

    Chen, Qian; Yan, Xinxing; Du, Zhiyun; Zhang, Kun; Wen, Chunxiao

    2016-01-01

    The novel P-arylation of dialkyl phosphites and secondary phosphine oxides with arynes has been achieved. The reactions produce dialkyl arylphosphonates in 71-99% yield and tertiary phosphine oxides in 68-92% yield under mild conditions. PMID:26651021

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

    E-print Network

    Abdou, Hanan E.

    Three-coordinate, luminescent, water-soluble gold(I) phosphine complexes: structural. a, * a Laboratory for Molecular Structure and Bonding, Department of Chemistry, Texas A & M, TPPTS0/tris-sulfonatophenyl phosphine, has been structurally characterized. The X-ray data

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

    E-print Network

    Bluemel, Janet

    , suspension NMR spectroscopy3can be applied routinely. Since most transition metals form stable phosphine com to bonding via one, two, or three siloxane bridges and there is also the possibility of cross- linking.' Therefore, we used the monoethoxy phosphine PPh2(C6H4)SiMe20Et1 that forms just one siloxane bridge when

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

    E-print Network

    Toste, Dean

    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

  18. Polyimides Containing Pendent Phosphine Oxide Groups for Space Applications

    NASA Technical Reports Server (NTRS)

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

    2002-01-01

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

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

    PubMed Central

    2013-01-01

    The new binuclear chromium Pacman complex [Cr2(L)] of the Schiff base pyrrole macrocycle H4L has been synthesized and structurally characterized. Addition of isocyanide, C?NR (R = xylyl, 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

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

    PubMed

    Bo, Liu; Fanhua, Zhang; Yuejin, Wang

    2010-12-01

    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

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

    PubMed Central

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

    2009-01-01

    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

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

    SciTech Connect

    Imyanitov, N.S.; Tupitsyn, S.B.

    1993-12-31

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

  3. Reaction of 2H-Azirine-Phosphine Oxides and -Phosphonates with Enolates Derived from ?-Keto Esters.

    PubMed

    Vélez Del Burgo, Ander; Ochoa de Retana, Ana M; de Los Santos, Jesús M; Palacios, Francisco

    2016-01-01

    Cyclopenta[b]-pyrrole-2-phosphine oxides 4a and -phosphonates 4b,c are generated by the addition of cyclic enolates derived from ethyl 2-oxo-cyclopentanecarboxylate 2 to phosphorated 2H-azirines 1. However, the addition of enolate derived from acyclic 2-oxo-butanoate 10 to 2H-azirine phosphine oxide 1 led to vinylogous N-acyl-?-aminoalkyl phosphine oxides 12, involving the carbonyl group and the C? of the keto ester 10. Ring closure of vinylogous derivative 12 in the presence of base afforded pyrrole-2-phosphine oxide 11. The addition of enolates derived from indenone-carboxylate 15 to 2H-azirines 1 led to the formation of functionalized N-substituted 1H-benzo[d]azepine derivatives 17. PMID:26640969

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

    E-print Network

    Lee, Sarah Yunmi

    Substantial progress has been described in the development of asymmetric variants of the phosphine-catalyzed intermolecular [3+2] annulation of allenes with alkenes; however, there have not been corresponding advances for ...

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

    DOEpatents

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

    2000-01-01

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

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

    DOEpatents

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

    1999-01-01

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

  7. Correction: Bifunctional ligands in combination with phosphines and Lewis acidic phosphoniums for the carbonylative Sonogashira reaction.

    PubMed

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

    2016-01-11

    Correction for 'Bifunctional ligands in combination with phosphines and Lewis acidic phosphoniums for the carbonylative Sonogashira reaction' by Chen Tan et al., Chem. Commun., 2015, 51, 10871-10874. PMID:26660541

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

    E-print Network

    Maimone, Thomas J.

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

  9. Reaction paths of phosphine dissociation on silicon (001).

    PubMed

    Warschkow, O; Curson, N J; Schofield, S R; Marks, N A; Wilson, H F; Radny, M W; Smith, P V; Reusch, T C G; McKenzie, D R; Simmons, M Y

    2016-01-01

    Using density functional theory and guided by extensive scanning tunneling microscopy (STM) image data, we formulate a detailed mechanism for the dissociation of phosphine (PH3) molecules on the Si(001) surface at room temperature. We distinguish between a main sequence of dissociation that involves PH2+H, PH+2H, and P+3H as observable intermediates, and a secondary sequence that gives rise to PH+H, P+2H, and isolated phosphorus adatoms. The latter sequence arises because PH2 fragments are surprisingly mobile on Si(001) and can diffuse away from the third hydrogen atom that makes up the PH3 stoichiometry. Our calculated activation energies describe the competition between diffusion and dissociation pathways and hence provide a comprehensive model for the numerous adsorbate species observed in STM experiments. PMID:26747816

  10. Dynamic control of chirality in phosphine ligands for enantioselective catalysis

    PubMed Central

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

    2015-01-01

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

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

    PubMed

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

    2004-07-01

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

  12. 40 CFR 721.10135 - Phosphinic acid, P,P-diethyl-, zinc salt (2:1).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Phosphinic acid, P,P-diethyl-, zinc... Specific Chemical Substances § 721.10135 Phosphinic acid, P,P-diethyl-, zinc salt (2:1). (a) Chemical... acid, P,P-diethyl-, zinc salt (2:1) (PMN P-05-11; CAS No. 284685-45-6) is subject to reporting...

  13. 40 CFR 721.10135 - Phosphinic acid, P,P-diethyl-, zinc salt (2:1).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Phosphinic acid, P,P-diethyl-, zinc... Specific Chemical Substances § 721.10135 Phosphinic acid, P,P-diethyl-, zinc salt (2:1). (a) Chemical... acid, P,P-diethyl-, zinc salt (2:1) (PMN P-05-11; CAS No. 284685-45-6) is subject to reporting...

  14. 40 CFR 721.10135 - Phosphinic acid, P,P-diethyl-, zinc salt (2:1).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Phosphinic acid, P,P-diethyl-, zinc... Specific Chemical Substances § 721.10135 Phosphinic acid, P,P-diethyl-, zinc salt (2:1). (a) Chemical... acid, P,P-diethyl-, zinc salt (2:1) (PMN P-05-11; CAS No. 284685-45-6) is subject to reporting...

  15. 40 CFR 721.10135 - Phosphinic acid, P,P-diethyl-, zinc salt (2:1).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Phosphinic acid, P,P-diethyl-, zinc... Specific Chemical Substances § 721.10135 Phosphinic acid, P,P-diethyl-, zinc salt (2:1). (a) Chemical... acid, P,P-diethyl-, zinc salt (2:1) (PMN P-05-11; CAS No. 284685-45-6) is subject to reporting...

  16. 40 CFR 721.10135 - Phosphinic acid, P,P-diethyl-, zinc salt (2:1).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Phosphinic acid, P,P-diethyl-, zinc... Specific Chemical Substances § 721.10135 Phosphinic acid, P,P-diethyl-, zinc salt (2:1). (a) Chemical... acid, P,P-diethyl-, zinc salt (2:1) (PMN P-05-11; CAS No. 284685-45-6) is subject to reporting...

  17. Biomimetic peptide-based models of [FeFe]-hydrogenases: utilization of phosphine-containing peptides.

    PubMed

    Roy, Souvik; Nguyen, Thuy-Ai D; Gan, Lu; Jones, Anne K

    2015-09-01

    Two synthetic strategies for incorporating diiron analogues of [FeFe]-hydrogenases into short peptides via phosphine functional groups are described. First, utilizing the amine side chain of lysine as an anchor, phosphine carboxylic acids can be coupled via amide formation to resin-bound peptides. Second, artificial, phosphine-containing amino acids can be directly incorporated into peptides via solution phase peptide synthesis. The second approach is demonstrated using three amino acids each with a different phosphine substituent (diphenyl, diisopropyl, and diethyl phosphine). In total, five distinct monophosphine-substituted, diiron model complexes were prepared by reaction of the phosphine-peptides with diiron hexacarbonyl precursors, either (?-pdt)Fe2(CO)6 or (?-bdt)Fe2(CO)6 (pdt = propane-1,3-dithiolate, bdt = benzene-1,2-dithiolate). Formation of the complexes was confirmed by UV/Vis, FTIR and (31)P NMR spectroscopy. Electrocatalysis by these complexes is reported in the presence of acetic acid in mixed aqueous-organic solutions. Addition of water results in enhancement of the catalytic rates. PMID:26223293

  18. Effect of Low-Temperature Phosphine Fumigation on the Survival of Bactrocera correcta (Diptera: Tephritidae).

    PubMed

    Liu, Tao; Li, Li; Zhang, Fanhua; Gong, Shaorun; Li, Tianxiu; Zhan, Guoping; Wang, Yuejin

    2015-08-01

    This laboratory-based study examined the effects of low-temperature phosphine fumigation on the survival of the eggs and larvae of the guava fruit fly, Bactrocera correcta (Bezzi). Individual flies at different developmental stages, from 6-h-old eggs to third instars, were exposed to 0.92?mg/liter phosphine for 1-7?d at 5°C. We found that 12-h-old eggs and third instars were the most tolerant to phosphine. Increasing phosphine concentrations from 0.46 to 4.56?mg/liter increased mortality in these two stages. However, increased exposure times were required to achieve equal mortality rates in 12-h-old eggs and third instars when phosphine concentrations were ?4.56 and ?3.65?mg/liter, respectively. C(n)t?=?k expression was obtained at 50, 90, and 99% mortality levels, and the toxicity index (n) ranged from 0.43 to 0.77 for the two stages. The synergistic effects of a controlled atmosphere (CA) with elevated CO2 levels were also investigated, and we found that a CO2 concentration between 10% and 15% under CA conditions was optimal for low-temperature phosphine fumigation. PMID:26470302

  19. Influence of structure of the metal salts of phosphinates on the performance of the fire-retardant polymers

    NASA Astrophysics Data System (ADS)

    Liu, Xueqing; Liu, Jiyan; Guo, Yuanhao; Cakmak, Miko

    2015-05-01

    Dialkylphosphinate salts (I) and amide-containing phosphinate salts(II) with varying metal cation and organic groups were used as flame retardants for epoxy resin(EP), poly(butylene terephthalate) (PBT) correspondingly. Their flame retardancy, mechanical properties, thermal stability, compatibility between phosphinate salts and polymer, and leaching of the salts from the polymer were investigated with respect to the structure of phosphinate salts.

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

    E-print Network

    Trenkle, James D. (James Douglas)

    2007-01-01

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

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

    PubMed

    Yang, Yonghong; Coward, James K

    2007-07-20

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

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

    NASA Astrophysics Data System (ADS)

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

    2000-03-01

    The hygienic, physicochemical, and organoleptic qualities of white ginseng were monitored during 6 months under accelerated conditions (40°C, 90% r.h.) by observing its microbial populations, disinfestation, and some quality attributes following either gamma irradiation at 2.5-10 kGy or commercial phosphine (PH 3) fumigation. In a comparative study, both treatments were found to be effective for disinfecting the stored samples. Phosphine showed no appreciable decontaminating effects on microorganisms contaminated including coliforms, while 5 kGy irradiation was sufficient to control all microorganisms related to the quality of the packed samples. Irradiation at 5 kGy caused negligible changes in physicochemical attributes of the samples, such as ginsenosides, amino acids, fatty acids, and organoleptic properties, whereas phosphine fumigation was found detrimental to sensory flavor ( P<0.01). Quality deterioration occurred in the commercially-packed samples was in the following order: the control, 10 kGy-, phosphine-, and 2.5-5 kGy-treated samples. Accordingly, irradiation at <5 kGy was found to be an effective alternative to phosphine fumigation for white ginseng.

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

    DOEpatents

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

    2004-08-24

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

  4. Phosphine derivatives of sparfloxacin - Synthesis, structures and in vitro activity

    NASA Astrophysics Data System (ADS)

    Komarnicka, Urszula K.; Starosta, Rados?aw; Guz-Regner, Katarzyna; Bugla-P?osko?ska, Gabriela; Kyzio?, Agnieszka; Je?owska-Bojczuk, Ma?gorzata

    2015-09-01

    We synthesized two derivatives of sparfloxacin (HSf): aminomethyl(diphenyl)phosphine (PSf) and its oxide (OPSf). The compounds were characterized by NMR spectroscopy, MS and elemental analysis. In addition, the molecular structures of the compounds were determined using DFT and X-ray (OPSf) analysis. The antibacterial activity of HSf and both derivatives was tested against four reference and fifteen clinical Gram-positive and Gram-negative strains of bacteria (sensitive or resistant to fluoroquinolones). The results showed that the activity of PSf was similar to or higher than the activity of HSf, while OPSf was found significantly less active. The compounds were also tested in vitro toward the following cancer cell lines: mouse colon carcinoma (CT26) and human lung adenocarcinoma (A549). Regardless of the cancer cell line, derivatization of HSf resulted in the gradual increase of cytotoxicity. OPSf exhibited the highest one (4 h - incubation time: IC50(CT26) = 51.0 ± 1.2; IC50(A549) = 74.9 ± 1.4 and 24 h: IC50(CT26) = 109.2 ± 8.8; IC50(A549) = 52.7 ± 9.2).

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

    E-print Network

    Hicks, Robert F.

    Phosphine Adsorption on the In-Rich InP(001) Surface: Evidence of Surface Dative Bonds at Room, Indiana 47405 Robyn L. Woo and Robert F. Hicks* Department of Chemical and Biomolecular Engineering, Uni of phosphine on indium phosphide compound semiconductor surfaces is a key process during the chemical vapor

  6. Palladium-catalyzed asymmetric addition of diarylphosphines to ?,?-unsaturated sulfonic esters for the synthesis of chiral phosphine sulfonate compounds.

    PubMed

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

    2013-10-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2010-08-01

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

  8. Mitochondrial uncouplers act synergistically with the fumigant phosphine to disrupt mitochondrial membrane potential and cause cell death.

    PubMed

    Valmas, Nicholas; Zuryn, Steven; Ebert, Paul R

    2008-10-30

    Phosphine is the most widely used fumigant for the protection of stored commodities against insect pests, especially food products such as grain. However, pest insects are developing resistance to phosphine and thereby threatening its future use. As phosphine inhibits cytochrome c oxidase (complex IV) of the mitochondrial respiratory chain and reduces the strength of the mitochondrial membrane potential (DeltaPsi(m)), we reasoned that mitochondrial uncouplers should act synergistically with phosphine. The mitochondrial uncouplers FCCP and PCP caused complete mortality in populations of both wild-type and phosphine-resistant lines of Caenorhabditis elegans simultaneously exposed to uncoupler and phosphine at concentrations that were individually nonlethal. Strong synergism was also observed with a third uncoupler DNP. We have also tested an alternative complex IV inhibitor, azide, with FCCP and found that this also caused a synergistic enhancement of toxicity in C. elegans. To investigate potential causes of the synergism, we measured DeltaPsi(m), ATP content, and oxidative damage (lipid hydroperoxides) in nematodes subjected to phosphine-FCCP treatment and found that neither an observed 50% depletion in ATP nor oxidative stress accounted for the synergistic effect. Instead, a synergistic reduction in DeltaPsi(m) was observed upon phosphine-FCCP co-treatment suggesting that this is directly responsible for the subsequent mortality. These results support the hypothesis that phosphine-induced mortality results from the in vivo disruption of normal mitochondrial activity. Furthermore, we have identified a novel pathway that can be targeted to overcome genetic resistance to phosphine. PMID:18755236

  9. Fixed-charge phosphine ligands to explore gas-phase coinage metal-mediated decarboxylation reactions.

    PubMed

    Vikse, Krista; Khairallah, George N; McIndoe, J Scott; O'Hair, Richard A J

    2013-05-14

    A combination of multistage mass spectrometry experiments and density functional theory (DFT) calculations were used to examine the decarboxylation reactions of a series of metal carboxylate complexes bearing a fixed-charge phosphine ligand, [(O3SC6H4)(C6H5)2PM(I)O2CR](-) (M = Cu, Ag, Au; R = Me, Et, benzyl, Ph). Collision-induced dissociation (CID) of these complexes using an LTQ linear ion mass spectrometer results in three main classes of reactions being observed: (1) decarboxylation; (2) loss of the phosphine ligand; (3) loss of carboxylic acid. The gas-phase unimolecular chemistry of the resultant decarboxylated organometallic ions, [(O3SC6H4)(C6H5)2PM(I)R](-), were also explored using CID experiments, and fragment primarily via loss of the phosphine ligand. Energy-resolved CID experiments on [(O3SC6H4)(C6H5)2PM(I)O2CR](-) (M = Cu, Ag, Au; R = Me, Et, benzyl, Ph) using a Q-TOF mass spectrometer were performed to gain a more detailed understanding of the factors influencing coinage metal-catalyzed decarboxylation and DFT calculations on the major fragmentation pathways aided in interpretation of the experimental results. Key findings are that: (1) the energy required for loss of the phosphine ligand follows the order Ag < Cu < Au; (2) the ease of decarboxylation of the coordinated RCO2 groups follows the order of R: Ph < PhCH2 < Me < Et; (3) in general, copper is best at facilitating decarboxylation, followed by gold then silver. The one exception to this trend is when R = Ph and M = Au which has the highest overall propensity for decarboxylation. The influence of the phosphine ligand on decarboxylation is also considered in comparison with previous studies on metal carboxylates that do not contain a phosphine ligand. PMID:23467311

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

    PubMed Central

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

    2014-01-01

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

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

    PubMed

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

    2014-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-07-01

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

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

    DOEpatents

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

    1999-01-05

    A compound and method of making a compound for use as a diagnostic or therapeutic pharmaceutical comprises at least one functionalized hydroxyalkyl phosphine donor group and one or more sulfur or nitrogen donor and a metal combined with the ligand. 21 figs.

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

    DOEpatents

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

    1998-12-01

    A complex and method for making a diagnostic or therapeutic pharmaceutical includes a ligand comprising at least one hydroxyalkyl phosphine donor group bound to a gold atom to form a gold-ligand complex that is stable in aqueous solutions containing oxygen, serum and other body fluids. 20 figs.

  15. 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...

  16. 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 ...

  17. 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...

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

    SciTech Connect

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

    1988-01-01

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

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

    ERIC Educational Resources Information Center

    Montgomery, Craig D.

    2013-01-01

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

  20. Synthesis of anionic methylpalladium complexes with phosphine-sulfonate ligands and their activities for olefin polymerization.

    PubMed

    Kochi, Takuya; Yoshimura, Kenji; Nozaki, Kyoko

    2006-01-01

    Reaction of diarylphosphinobenzene-2-sulfonic acids with tertially amines, followed by addition of [PdMeCl(cod)], provided anionic methylpalladium(II) complexes with bidentate phosphine-sulfonate ligands, which show high activity for copolymerization of ethylene with methyl acrylate. PMID:16357956

  1. 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...

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

    E-print Network

    Toste, Dean

    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

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

    DOEpatents

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

    1998-01-01

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

  4. Stereoselective synthesis of vinylphosphonates and phosphine oxides via silver-catalyzed phosphorylation of styrenes.

    PubMed

    Gui, Qingwen; Hu, Liang; Chen, Xiang; Liu, Jidan; Tan, Ze

    2015-09-21

    An efficient and stereoselective synthesis of vinylphosphonates and phosphine oxides was developed starting from styrenes using AgNO3 as the catalyst and K2S2O8 as the oxidant. The success of the reaction was found to be critically dependent on the use of TEMPO as the additive. PMID:26239098

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

    E-print Network

    Smith, Sean W.

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

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

    E-print Network

    Huacuja, Rafael

    2014-01-17

    This dissertation discusses the synthesis and reactivity of divalent palladium complexes supported by diarylamido bis-phosphine pincer ligands (PNP). The PNP is a tridentate pincer type ligand which typically adopts meridional type coordination...

  7. Oxygenated Phosphine Fumigation for Control of Light Brown Apple Moth (Lepidoptera: Tortricidae) Eggs on Cut-Flowers.

    PubMed

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

    2015-08-01

    Light brown apple moth, Epiphyas postvittana (Walker), eggs were subjected to oxygenated phosphine fumigation treatments under 70% oxygen on cut flowers to determine efficacy and safety. Five cut flower species: roses, lilies, tulips, gerbera daisy, and pompon chrysanthemums, were fumigated in separate groups with 2,500?ppm phosphine for 72?h at 5°C. Egg mortality and postharvest quality of cut flowers were determined after fumigation. Egg mortalities of 99.7-100% were achieved among the cut flower species. The treatment was safe to all cut flowers except gerbera daisy. A 96-h fumigation treatment with 2,200?ppm phosphine of eggs on chrysanthemums cut flowers also did not achieve complete control of light brown apple moth eggs. A simulation of fumigation in hermetically sealed fumigation chambers with gerbera daisy showed significant accumulations of carbon dioxide and ethylene by the end of 72-h sealing. However, oxygenated phosphine fumigations with carbon dioxide and ethylene absorbents did not reduce the injury to gerbera daisy, indicating that it is likely that phosphine may directly cause the injury to gerbera daisy cut flowers. The study demonstrated that oxygenated phosphine fumigation is effective against light brown apple moth eggs. However, it may not be able to achieve the probit9 quarantine level of control and the treatment was safe to most of the cut flower species. PMID:26470303

  8. Continuous real-time monitoring of phosphine concentrations in air using electrochemical detectors interfaced by radio telemetry.

    PubMed

    Thorn, Tommy G; Chodyniecki, Edward M; Ingold, Kenneth W; Long, Gerald A; Miller, Charles D; Robinson, Edward A; Cowan, F Scott; Thomas, Robert L

    2002-05-01

    This work involves the novel use of a radio telemetry-based system that continuously monitors phosphine using two different types of electrochemical detectors (ECD/RT). The ECD/RT units were used to monitor phosphine inside and at varying distances from large tobacco storage warehouses. A master controller unit transferred the data to a personal computer that received and displayed the data. Supervisory control and data acquisition software assimilated the data from each ECD/RT unit, displayed and updated it as new transmissions were received, and stored the data in secure databases. Phosphine concentrations outside five warehouses simultaneously under fumigation and at the facility boundaries were <0.3 parts per million (ppm). Phosphine levels ranged from 0 to 580 ppm inside sealed warehouses. A comparison was made between the data collected at an ECD/RT unit approximately 4 m downwind of a sealed warehouse and a colorimetric tube at the same location. The final phosphine concentration from the colorimetric method was 0.05 ppm and the average over the 20-minute collection period for the ECD/RT was 0.13 ppm. This system allows for continuous, remote monitoring around warehouses under fumigation and superior time resolution allowing timely response to fugitive emissions of phosphine. PMID:12026991

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

    SciTech Connect

    Rosario-Amorin, Daniel; Ouizem, Sabrina; Dickie, D. A.; Paine, Robert T.; Cramer, Roger E.; Hay, Benjamin; Podair, Julien; Delmau, Laetitia Helene

    2014-01-01

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

  10. Syntheses and properties of phosphine-substituted ruthenium(II) polypyridine complexes with nitrogen oxides.

    PubMed

    Nakamura, Go; Kondo, Mio; Crisalli, Meredith; Lee, Sze Koon; Shibata, Akane; Ford, Peter C; Masaoka, Shigeyuki

    2015-10-21

    Four novel phosphine-substituted ruthenium(ii) polypyridine complexes with nitrogen oxides-trans(P,NO2)-[Ru(trpy)(Pqn)(NO2)]PF6 (trans-NO2), cis(P,NO2)-[Ru(trpy)(Pqn)(NO2)]PF6 (cis-NO2), [Ru(trpy)(dppbz)(NO2)]PF6 (PP-NO2), and cis(P,NO)-[Ru(trpy)(Pqn)(NO)](PF6)3 (cis-NO)-were synthesised (trpy = 2,2':6',2''-terpyridine, Pqn = 8-(diphenylphosphanyl)quinoline, and dppbz = 1,2-bis(diphenylphosphanyl)benzene). The influence of the number and position of the phosphine group(s) on the electronic structure of these complexes was investigated using single-crystal X-ray structural analysis, UV-vis absorption spectroscopy, and electrochemical measurements. The substitution lability of the nitrogen oxide ligand of each complex is discussed in comparison with that of the corresponding acetonitrile complexes. PMID:26373342

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

    NASA Technical Reports Server (NTRS)

    Ferris, J. P.; Benson, R.

    1980-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1987-01-01

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

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

    PubMed

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

    2013-09-01

    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

  14. Phosphine-catalyzed domino reactions: a route to functionalized bicyclic skeletons.

    PubMed

    Li, Erqing; Huang, You

    2014-03-17

    A novel strategy that involves phosphine-catalyzed sequential [2+3] and [3+2] annulation reactions was developed. In this domino reaction, ?-substituted allenoates were used as novel C4 synthons, and the bicyclic cyclopenta[b]dihydrofuran derivatives were produced in good to excellent diastereoselectivities and yields under mild conditions. Furthermore, preliminary studies on an asymmetric variant of this reaction proceeded with moderate enantioselectivity. PMID:24523030

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

    NASA Astrophysics Data System (ADS)

    Bampoh, Victoria Naa Kwale

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

  16. P-chiral phosphine-sulfonate/palladium-catalyzed asymmetric copolymerization of vinyl acetate with carbon monoxide.

    PubMed

    Nakamura, Akifumi; Kageyama, Takeharu; Goto, Hiroki; Carrow, Brad P; Ito, Shingo; Nozaki, Kyoko

    2012-08-01

    Utilization of palladium catalysts bearing a P-chiral phosphine-sulfonate ligand enabled asymmetric copolymerization of vinyl acetate with carbon monoxide. The obtained ?-polyketones have head-to-tail and isotactic polymer structures. The origin of the regio- and stereoregularities was elucidated by stoichiometric reactions of acylpalladium complexes with vinyl acetate. The present report for the first time demonstrates successful asymmetric coordination-insertion (co)polymerization of vinyl acetate. PMID:22823453

  17. Ethylene/allyl monomer cooligomerization by nickel/phosphine-sulfonate catalysts.

    PubMed

    Ito, Shingo; Ota, Yusuke; Nozaki, Kyoko

    2012-12-01

    Nickel(II) complexes bearing a phosphine-sulfonate ligand, [(R(2)PC(6)H(4)SO(3))NiMe(2,6-lutidine)] (R = cyclohexyl, 2-MeOC(6)H(4), and 2-[2',6'-(MeO)(2)C(6)H(3)]C(6)H(4), were synthesized and applied as catalysts for the cooligomerizations of ethylene and allyl monomers. PMID:23059906

  18. Phosphine-free synthesis of Ag-In-Se alloy nanocrystals with visible emissions.

    PubMed

    Yao, Dong; Liu, Huiwen; Liu, Yi; Dong, Chunwei; Zhang, Kai; Sheng, Yu; Cui, Jianli; Zhang, Hao; Yang, Bai

    2015-11-28

    As promising heavy metal-free emitting materials, Ag-In-Se nanocrystals (NCs) are conventionally synthesized using organic phosphine agents and exhibit near-infrared emissions. In this work, we demonstrate a rapid phosphine-free approach for synthesizing Ag-In-Se alloy NCs with the emissions tunable to the visible region on the basis of the phosphine-free dissolution of Se powder. At room temperature, Se powder is reduced by dodecanethiol and dissolved in oleylamine to produce a Se precursor. The resultant Se precursor is highly active, which permits rapid synthesis at a relatively low temperature, such as at 90 °C for 150 s. By optimizing the size, structure, and composition, the photoluminescence quantum yield of the as-synthesized Ag-In-Se NCs is enhanced to up to 10%. The growth of the Ag-In-Se NCs involves composition and phase transition, which strongly depend on the reaction temperature. The Ag2Se nuclei form first, and the Ag-In-Se NCs are produced by doping In(3+) into the preformed Ag2Se nuclei. Tetragonal phase Ag-In-Se is obtained below 170 °C, while the orthorhombic phase appears over 190 °C. The potential of Ag-In-Se NCs as red emitting phosphors for lighting-emitting diodes is further demonstrated. PMID:26489872

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

    SciTech Connect

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

    2007-11-19

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

  20. 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

    Girolami, Gregory S.

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-02-01

    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.

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

    PubMed

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

    2015-02-27

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

  3. Phosphine-free synthesis of Ag-In-Se alloy nanocrystals with visible emissions

    NASA Astrophysics Data System (ADS)

    Yao, Dong; Liu, Huiwen; Liu, Yi; Dong, Chunwei; Zhang, Kai; Sheng, Yu; Cui, Jianli; Zhang, Hao; Yang, Bai

    2015-11-01

    As promising heavy metal-free emitting materials, Ag-In-Se nanocrystals (NCs) are conventionally synthesized using organic phosphine agents and exhibit near-infrared emissions. In this work, we demonstrate a rapid phosphine-free approach for synthesizing Ag-In-Se alloy NCs with the emissions tunable to the visible region on the basis of the phosphine-free dissolution of Se powder. At room temperature, Se powder is reduced by dodecanethiol and dissolved in oleylamine to produce a Se precursor. The resultant Se precursor is highly active, which permits rapid synthesis at a relatively low temperature, such as at 90 °C for 150 s. By optimizing the size, structure, and composition, the photoluminescence quantum yield of the as-synthesized Ag-In-Se NCs is enhanced to up to 10%. The growth of the Ag-In-Se NCs involves composition and phase transition, which strongly depend on the reaction temperature. The Ag2Se nuclei form first, and the Ag-In-Se NCs are produced by doping In3+ into the preformed Ag2Se nuclei. Tetragonal phase Ag-In-Se is obtained below 170 °C, while the orthorhombic phase appears over 190 °C. The potential of Ag-In-Se NCs as red emitting phosphors for lighting-emitting diodes is further demonstrated.As promising heavy metal-free emitting materials, Ag-In-Se nanocrystals (NCs) are conventionally synthesized using organic phosphine agents and exhibit near-infrared emissions. In this work, we demonstrate a rapid phosphine-free approach for synthesizing Ag-In-Se alloy NCs with the emissions tunable to the visible region on the basis of the phosphine-free dissolution of Se powder. At room temperature, Se powder is reduced by dodecanethiol and dissolved in oleylamine to produce a Se precursor. The resultant Se precursor is highly active, which permits rapid synthesis at a relatively low temperature, such as at 90 °C for 150 s. By optimizing the size, structure, and composition, the photoluminescence quantum yield of the as-synthesized Ag-In-Se NCs is enhanced to up to 10%. The growth of the Ag-In-Se NCs involves composition and phase transition, which strongly depend on the reaction temperature. The Ag2Se nuclei form first, and the Ag-In-Se NCs are produced by doping In3+ into the preformed Ag2Se nuclei. Tetragonal phase Ag-In-Se is obtained below 170 °C, while the orthorhombic phase appears over 190 °C. The potential of Ag-In-Se NCs as red emitting phosphors for lighting-emitting diodes is further demonstrated. Electronic supplementary information (ESI) available: Additional characterization of Ag-In-Se and Ag2Se NCs. See DOI: 10.1039/c5nr04856g

  4. Redox Chemistry of Gold(I) Phosphine Thiolates: Sulfur-Based Oxidation

    PubMed Central

    Jiang, Tong; Wei, Gang; Turmel, Cristopher; Bruce, Alice E.

    1994-01-01

    The redox chemistry of mononuclear and dinuclear gold(I) phosphine arylthiolate complexes was recently investigated by using electrochemical, chemical, and photochemical techniques. We now report the redox chemistry of dinuclear gold(I) phosphine complexes containing aliphatic dithiolate ligands. These molecules differ from previously studied gold(I) phosphine thiolate complexes in that they are cyclic and contain aliphatic thiolates. Cyclic voltammetry experiments of Au2 (LL)(pdt) [pdt = propanedithiol; LL = 1,2-bis(diphenylphosphino)-ethane (dppe), 1,3-bis(diphenylphosphino)propane (dppp), 1,4-bis(diphenylphosphino)butane (dppb), 1,5-bis(diphenylphosphino)pentane (dpppn)] in 0.1 M TBAH/CH3CN or CH2Cl2 solutions at 50 to 500 mV/sec using glassy carbon or platinum electrodes, show two irreversible anodic processes at ca. +0.6 and +1.1 V (vs. SCE). Bulk electrolyses at +0.9 V and +1.4 V result in n values of 0.95 and 3.7, respectively. Chemical oxidation of Au2(dppp)(pdt) using one equivalent of Br2 (2 oxidizing equivalents) yields 1,2-dithiolane and Au2(dppp)Br2. The reactivity seen upon mild oxidation ? +1.0 V is consistent with formal oxidation of a thiolate ligand, followed by a fast chemical reaction that results in cleavage of a second gold-sulfur bond. Oxidation at higher potentials (? +1.3 V) is consistent with oxidation of gold(I) to gold(III). Structural and electrochemical differences between gold(I) aromatic and aliphatic thiolate oxidation processes are discussed. PMID:18476260

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

    PubMed

    Lim, Sang Ho; Cohen, Seth M

    2013-07-15

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

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

    PubMed

    Wambach, Truman C; Fryzuk, Michael D

    2015-06-15

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

  7. Water-Soluble Iridium-NHC-Phosphine Complexes as Catalysts for Chemical Hydrogen Batteries Based on Formate.

    PubMed

    Horváth, Henrietta; Papp, Gábor; Szabolcsi, Roland; Kathó, Ágnes; Joó, Ferenc

    2015-09-21

    Molecular hydrogen, obtained by water electrolysis or photocatalytic water splitting, can be used to store energy obtained from intermittent sources such as wind and solar power. The storage and safe transportation of H2 , however, is an open and central question in such a hydrogen economy. Easy-to-synthesize, water-soluble iridium-N-heterocyclic carbene-phosphine (Ir(I) -NHC-phosphine) catalysts show unprecedented high catalytic activity in dehydrogenation of aqueous sodium formate. Fast reversible generation and storage of hydrogen can be achieved with these catalysts by a simple decrease or increase in the hydrogen pressure, respectively. PMID:26289830

  8. Loss of phosphine from unsealed bins of wheat at six combinations of grain temperature and grain moisture content.

    PubMed

    Reed; Pan

    2000-07-01

    Hard red winter wheat (1.4 t) at 11.1 or 13.5% moisture content (wet basis) and 20, 25, or 30 degrees C was fumigated with tablets of an aluminum phosphide formulation in unsealed, cylindrical grain bins of corrugated metal. The fumigant leakage rate was manipulated to approximate that commonly encountered in farm and commercial-scale bins of this type. Phosphine concentration profiles were recorded and phosphine loss and sorption were characterized to determine which conditions provided the greatest probability of successful fumigation in these bins. Phosphine leakage and sorption were both positively related to grain temperature and moisture content. The fumigant concentration profiles were compared with previously-published data relating temperature to the developmental rate and fumigant susceptibility of lesser grain borer eggs, which are phosphine-resistant but become less resistant as they age. The mean phosphine concentration observed at the time corresponding to one-half of the calculated egg development time was compared to the lethal concentration (LC(99)) for a 2-day exposure at each temperature-moisture combination. In the low-moisture grain at 20 degrees C, the observed fumigant concentration was below the lethal concentration, due to the long development time under these conditions. At 25 and 30 degrees C in the low-moisture wheat, the likelihood of complete kill appeared more favorable because the fumigant concentration remained above the published LC(99) for more than half of the egg development time. In the wheat with 13.5% moisture content, rapid fumigant sorption and loss resulted in phosphine concentrations below the LC(99) at one-half of the development time at 20 or 25 degrees C. At 30 degrees C, due to the very rapid development rate, the observed phosphine concentration exceeded the LC(99) half-way through the egg development period despite the rapid rate of fumigant sorption and loss. Repeated fumigation of the same grain reduced the rate at which phosphine sorbed into the grain. PMID:10758265

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

    PubMed Central

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

    2015-01-01

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

  10. Reduction of 4-azidonaphthalimide with different phosphine ligands and exploration of their spectroscopic properties

    NASA Astrophysics Data System (ADS)

    Xu, Shou De; Fang, Cheng Hui; Tian, Guang Xuan; Chen, Yi; Dou, Ye Hong; Kou, Jun Feng; Wu, Xiang Hua

    2015-12-01

    A convenient, high efficient method for the reduction of 4-azidonaphthalimide to 4-aminonaphthalimide (1) by using PMe3 has been developed. Several 4-substituted 1,8-naphthalimide iminophosphoranes were also successfully synthesized. Their structures were characterized by NMR and MS analyses. The structures of compounds 2 and 3 were also confirmed by single crystal X-ray diffraction analysis. Their optoelectronic properties of these naphthalimides were investigated. The results indicated that their optical properties could be tuned by different phosphine ligands, which make them novel potential organic luminescent materials.

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

    DOEpatents

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

    1989-10-17

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

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

    DOEpatents

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

    1989-01-01

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

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

    E-print Network

    Hilliard, Casie Renee

    2013-12-09

    , resulting in a parachute-type compound (Figure 1.1).13 Therefore, a more P P P P SiO2 31P CP/MAS 3 kHz polycrystalline 3 kHz 0 kHz 0 kHz 1 1ads adsorbed 5 rigid system is desired to ensure that only one phosphine group per molecule can... the metal complexes, and this is important for our adsorption studies to ensure the cage is rigid 6 enough and cannot fold to form a parachute on the surface. In addition, we want to utilize the dioxide cages (III) because they incorporate...

  14. Facile, Catalytic Dehydrocoupling of Phosphines Using ?-Diketiminate Iron(II) Complexes.

    PubMed

    King, Andrew K; Buchard, Antoine; Mahon, Mary F; Webster, Ruth L

    2015-11-01

    Catalytic dehydrocoupling of primary and secondary phosphines has been achieved for the first time using an iron pre-catalyst. The reaction proceeds under mild reaction conditions and is successful with a range of diarylphosphines. A proton acceptor is not needed for the transformation to take place, but addition of 1-hexene does allow for turnover at 50?°C. The catalytic system developed also facilitates the dehydrocoupling of phenylphosphane and dicyclohexylphosphane. A change in solvent switches off dehydrocoupling to allow hydrophosphination of alkenes. PMID:26406999

  15. /sup 31/P and /sup 119/Sn NMR of adducts of tin tetrahalides with tertiary phosphines

    SciTech Connect

    Yashina, N.S.; Gefel, E.I.; Kosina, A.N.; Petrosyan, V.S.; Reutov, O.A.

    1986-10-01

    The donor-acceptor interaction of SnX/sub 4/ (X = Cl, Br) with tertiary phosphines (nBu/sub 3/P, Me/sub 2/PhP, Ph/sub 3/P) has been studied by /sup 31/P and /sup 119/Sn spectroscopy over a broad range of temperatures and with varous donor-acceptor ratios (D/A) in solutions in methylene chloride. An analysis of the direct spin-spin coupling constants /sup 1/J(/sup 119/Sn-/sup 31/P) and the multiplicity in the /sup 119/Sn NMR spectra made it possible to propose a complexation mechanism, which includes the formation of intermediate ionic structures along with the molecular complexes AD and AD/sub 2/. It has been shown that an excess of the acceptor is not a sufficient condition for the formation of the complex AD. The coexistence of cis and trans isomers of the AD/sub 2/ complexes in solution has been established, and the dependence of /sup 1/J(/sup 119/Sn-/sup 31/P) on the geometry of the P-Sn-P fragment in the octahedral complexes has been demonstrated. The use of low-temperature NMR made it possible, in most cases, to suppress the occurrence of the redox reaction between the compounds of Sn(IV) and the tertiary phosphines.

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

    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.

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

    PubMed

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

    2013-01-01

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

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

    SciTech Connect

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

    2011-03-31

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

  19. Effects of Phosphine-Carbene Substitutions on the Electrochemical and Thermodynamic Properties of Nickel Complexes

    SciTech Connect

    Galan, Brandon R.; Wiedner, Eric S.; Helm, Monte L.; Linehan, John C.; Appel, Aaron M.

    2014-05-12

    Nickel(II) complexes containing chelating N-heterocyclic carbene-phosphine ligands ([NiL2](BPh4)2, for which L = [MeIm(CH2)2PR2]) have been synthesized for the purpose of studying how this class of ligand effects the electrochemical properties compared to the nickel bis- diphosphine analogues. The nickel complexes were synthesized and characterized by x-ray crystallography and electrochemical methods. Based on the half wave potentials (E1/2), substitution of an NHC for one of the phosphines in a diphoshine ligand results in shifts in potential to 0.6 V to 1.2 V more negative than the corresponding nickel bis-diphosphine complexes. These quantitative results highlight the substantial effect that NHC ligands can have upon the electronic properties of the metal complexes. BRG, JCL, and AMA acknowledge the support by the US Department of Energy Basic Energy Sciences, Division of Chemical Sciences, Geosciences & Biosciences. MLH acknoledges the support of the Center for Molecular Electrocatalysis, an Energy Frontier Research Center funded by the US Department of Energy, Office of Science, Office of Basic Energy Sciences. Pacific Northwest National Laboratory is operated by Battelle for the US Department of Energy.

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

    PubMed

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

    2015-06-11

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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  2. Oxygenated phosphine fumigation for control of light brown apple moth, Epiphyas postvittana (Lepidoptera: Tortricidae), eggs on cut-flowers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Light brown apple moth, Epiphyas postvittana, eggs were subjected to oxygenated phosphine fumigation treatments on cut flowers to determine efficacy and safety. Five cut flower species: roses, lilies, tulips, gerbera daisy, and pompon chrysanthemums, were fumigated in separate groups with 2500 ppm ...

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

    NASA Astrophysics Data System (ADS)

    Iwanaga, Hiroki; Amano, Akio; Oguchi, Masayuki

    2005-06-01

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

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

    PubMed

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

    2015-09-01

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

  5. Cyclopentadiene-Phosphine/Palladium-Catalyzed Synthesis of Indolizines from Pyrrole and 1,4-Dibromo-1,3-butadienes.

    PubMed

    Hao, Wei; Wang, Han; Ye, Qingyu; Zhang, Wen-Xiong; Xi, Zhenfeng

    2015-11-20

    The cyclopentadiene-phosphine ligand (L1) and palladium were found to be an efficient catalyst system to activate the ?-C(sp(2))-H bond of pyrrole and indole derivatives. Various alkenyl or aryl dibromides could be used to react with pyrrole and indole derivatives to afford multisubstituted indolizines in high yields. PMID:26522791

  6. C-N Coupling of Amides with Alcohols Catalyzed by N-Heterocyclic Carbene-Phosphine Iridium Complexes.

    PubMed

    Kerdphon, Sutthichat; Quan, Xu; Parihar, Vijay Singh; Andersson, Pher G

    2015-11-20

    N-Heterocyclic carbene-phosphine iridium complexes (NHC-Ir) were developed/found to be a highly reactive catalyst for N-monoalkylation of amides with alcohols via hydrogen transfer. The reaction produced the desired product in high isolated yields using a wide range of substrates with low catalyst loading and short reaction times. PMID:26489041

  7. Advances in postharvest pest control on perishable commodities using ultralow oxygen treatment and low temperature phosphine funigation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Recent research in postharvest pest control on fresh fruits and vegetables for export to markets have resulted in promising ultralow oxygen (ULO) treatments and low temperature phosphine fumigation treatments for a variety of pests on different commodities. Lettuce aphid (Nasonovia ribisnigri), wes...

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

    PubMed

    Kaur, R; Subbarayalu, M; Jagadeesan, R; Daglish, G J; Nayak, M K; Naik, H R; Ramasamy, S; Subramanian, C; Ebert, P R; Schlipalius, D I

    2015-09-01

    Phosphine (PH3) fumigation is the primary method worldwide for controlling insect pests of stored commodities. Over-reliance on phosphine, however, has led to the emergence of strong resistance. Detailed genetic studies previously identified two loci, rph1 and rph2, that interact synergistically to create a strong resistance phenotype. We compared the genetics of phosphine resistance in strains of Rhyzopertha dominica and Tribolium castaneum from India and Australia, countries having similar pest species but widely differing in pest management practices. Sequencing analysis of the rph2 locus, dihydrolipoamide dehydrogenase (dld), identified two structurally equivalent variants, Proline49>Serine (P49S) in one R. dominica strain and P45S in three strains of T. castaneum from India. These variants of the DLD protein likely affect FAD cofactor interaction with the enzyme. A survey of insects from storage facilities across southern India revealed that the P45/49S variant is distributed throughout the region at very high frequencies, in up to 94% of R. dominica and 97% of T. castaneum in the state of Tamil Nadu. The abundance of the P45/49S variant in insect populations contrasted sharply with the evolutionary record in which the variant was absent from eukaryotic DLD sequences. This suggests that the variant is unlikely to provide a strong selective advantage in the absence of phosphine fumigation. PMID:25853517

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

    SciTech Connect

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

    2013-03-07

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

  10. Mono-Oxidation of Bidentate Bis-phosphines in Catalyst Activation: Kinetic and Mechanistic Studies of a Pd/Xantphos-Catalyzed C-H Functionalization.

    PubMed

    Ji, Yining; Plata, R Erik; Regens, Christopher S; Hay, Michael; Schmidt, Michael; Razler, Thomas; Qiu, Yuping; Geng, Peng; Hsiao, Yi; Rosner, Thorsten; Eastgate, Martin D; Blackmond, Donna G

    2015-10-21

    Kinetic, spectroscopic, crystallographic, and computational studies probing a Pd-catalyzed C-H arylation reaction reveal that mono-oxidation of the bis-phosphine ligand is critical for the formation of the active catalyst. The bis-phosphine mono-oxide is shown to be a hemilabile, bidentate ligand for palladium. Isolation of the oxidative addition adduct, with structural elucidation by X-ray analysis, showed that the mono-oxide was catalytically competent, giving the same reaction rate in the productive reaction as the Pd(II)/xantphos precursor. A dual role for the carboxylate base in both catalyst activation and reaction turnover was demonstrated, along with the inhibiting effect of excess phosphine ligand. The generality of the role of phosphine mono-oxide complexes in Pd-catalyzed coupling processes is discussed. PMID:26461028

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  12. [Distributions of matrix-bound phosphine in surface sediments of the Yangtze Estuary].

    PubMed

    Li, Tao; Hou, Li-Jun; Liu, Min; Zhao, Di; Yin, Guo-Yu; Zheng, Yan-Ling; Zhao, Hui

    2012-10-01

    Concentrations of matrix-bound phosphine (MBP) in the surface sediments of the Yangtze Estuary were investigated in the present study using gas chromatography coupled with a pulsed flame photometric detector (GC-PFPD), and the potential environmental factors were discussed. It was shown that the MBP concentrations were relatively higher in May than in November, with the ranges of 139-426 ng x kg(-1) and 111-192 ng x kg(-1), respectively. Also, there was the significant spatial difference in MBP concentrations at the study area. In addition, it was observed that MBP was significantly related to TP, IP, OP, pH, and activities of APA in the surface sediments. However, no significant correlations were found between MBP, organic carbon and salinity. PMID:23233971

  13. Nickel Phosphine Catalysts with Pendant Amines for Electrocatalytic Oxidation of Alcohols

    SciTech Connect

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

    2015-01-01

    Nickel phosphine complexes with pendant amines have been found to be electrocatalysts for the oxidation of primary and secondary alcohols, with turnover frequencies as high as 3.3 s-1. These complexes are the first electrocatalysts for alcohol oxidation based on non-precious metals, which will be critical for use in fuel cells. The research by CJW, ESW, and AMA was supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences & Biosciences. The research by JASR was supported as part of the Center for Molecular Electrocatalysis, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science. Pacific Northwest National Laboratory is operated by Battelle for the US Department of Energy.

  14. Controlling olefin isomerization in the heck reaction with neopentyl phosphine ligands.

    PubMed

    Lauer, Matthew G; Thompson, Mallory K; Shaughnessy, Kevin H

    2014-11-21

    The use of neopentyl phosphine ligands was examined in the coupling of aryl bromides with alkenes. Di-tert-butylneopentylphosphine (DTBNpP) was found to promote Heck couplings with aryl bromides at ambient temperature. In the Heck coupling of cyclic alkenes, the degree of alkene isomerization was found to be controlled by the choice of ligand with DTBNpP promoting isomerization to a much greater extent than trineopentylphosphine (TNpP). Under optimal conditions, DTBNpP provides high selectivity for 2-aryl-2,3-dihydrofuran in the arylation of 2,3-dihydrofuran, whereas TNpP provided high selectivity for the isomeric 2-aryl-2,5-dihydrofuran. A similar complementary product selectivity is seen in the Heck coupling of cyclopentene. Heck coupling of 2-bromophenols or 2-bromoanilides with 2,3-dihydrofurans affords 2,5-epoxybenzoxepin and 2,5-epoxybenzazepins, respectively. PMID:25333873

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

    NASA Astrophysics Data System (ADS)

    Zhuang, Hong

    1998-11-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1986-01-01

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

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

    SciTech Connect

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

    2007-01-01

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

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

    PubMed Central

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

    2010-01-01

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

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

    PubMed

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

    2010-01-01

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

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

    PubMed

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

    2015-11-16

    The catalytic hydration of benzonitrile and acetonitrile has been studied by employing different arene-ruthenium(II) complexes with phosphinous (PR2 OH) and phosphorous acid (P(OR)2 OH) ligands as catalysts. Marked differences in activity were found, depending on the nature of both the P-donor and ?(6) -coordinated arene ligand. Faster transformations were always observed with the phosphinous acids. DFT computations unveiled the intriguing mechanism of acetonitrile hydration catalyzed by these arene-ruthenium(II) complexes. The process starts with attack on the nitrile carbon atom of the hydroxyl group of the P-donor ligand instead of on a solvent water molecule, as previously suggested. The experimental results presented herein for acetonitrile and benzonitrile hydration catalyzed by different arene-ruthenium(II) complexes could be rationalized in terms of such a mechanism. PMID:26448635

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

    PubMed Central

    Tin, Sergey; Fanjul, Tamara

    2015-01-01

    Summary In the hydrogenation of sluggish unactivated enamine substrates, Rh complexes of electron-deficient phosphines are demonstrated to be far more reactive catalysts than those derived from triphenylphosphine. These operate at low catalyst loadings (down to 0.01 mol %) and are able to reduce tetrasubstituted enamines. The use of the sustainable and environmentally benign solvent (R)-limonene for the reaction is also reported with the amine isolated by acid extraction. PMID:26124864

  2. Design, synthesis, and application of a chiral sulfinamide phosphine catalyst for the enantioselective intramolecular Rauhut-Currier reaction.

    PubMed

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

    2015-06-01

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

  3. Cationic Gold Clusters Ligated with Differently Substituted Phosphines: Effect of Substitution on Ligand Reactivity and Binding

    SciTech Connect

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

    2015-01-01

    We present a systematic study of the effect of the number of methyl (Me) and cyclohexyl (Cy) functional groups in monodentate phosphine ligands on the solution-phase synthesis of ligated sub-nanometer gold clusters and their gas-phase fragmentation pathways. Small mixed ligand cationic gold clusters were synthesized using ligand exchange reactions between pre-formed triphenylphosphine ligated (PPh3) gold clusters and monodentate Me- and Cy-substituted ligands in solution and characterized using electrospray ionization mass spectrometry (ESI-MS) and collision-induced dissociation (CID) experiments. Under the same experimental conditions, larger gold-PPh3 clusters undergo efficient exchange of unsubstituted PPh3 ligands for singly Me- and Cy-substituted PPh2Me and PPh2Cy ligands. The efficiency of ligand exchange decreases with an increasing number of Me or Cy groups in the substituted phosphine ligands. CID experiments performed for a series of ligand-exchanged gold clusters indicate that loss of a neutral Me-substituted ligand is preferred over loss of a neutral PPh¬3 ligand while the opposite trend is observed for Cy-substituted ligands. The branching ratio of the competing ligand loss channels is strongly correlated with the electron donating ability of the phosphorous lone pair as determined by the relative proton affinity of the ligand. The results indicate that the relative ligand binding energies increase in the order PMe3 < PPhMe2 < PPh2Me < PPh3< PPh2Cy < PPhCy2< PCy3. Furthermore, the difference in relative ligand binding energies increases with the number of substituted PPh3-mMem or PPh3-mCym ligands (L) exchanged onto each cluster. This study provides the first experimental determination of the relative binding energies of ligated gold clusters containing differently substituted monophosphine ligands, which are important to controlling their synthesis and reactivity in solution. The results also indicate that ligand substitution is an important parameter that must be considered in theoretical modeling of these complex systems

  4. Toxicity of phosphine on the developmental stages of rust-red flour beetle, Tribolium castaneum Herbst over a range of concentrations and exposures.

    PubMed

    Manivannan, S

    2015-10-01

    The susceptibility of the developmental stages of rust-red flour beetle, Tribolium castaneum to a range of concentrations of phosphine over varying durations from 24 to 168 h was reconnoitered in the laboratory at 25?±?2 °C. Responses of the life stages exposed to phosphine were compared with those of un-treated controls over 24, 48, 72, 96, 120, 144 and 168 h exposures and mortality was assessed after 14 days. Among the life stages tested, pupae were more tolerant to phosphine followed by the egg and the larval instars. At 24 h, the maximum LC50 value was observed in case of egg; 1.571 mgL(-1); followed by the pupae, 6(th) instar, 4(th) instar and 2(nd) instar larvae with LC50 values of 1.184, 0.336, 0.212 and 0.081 mgL(-1) respectively. However, continued exposure of the developmental stages to phosphine, recorded maximum LC values in the pupae followed by egg and the larval instars. A linear increase in the mortality response was witnessed in all the insect stages when the exposure periods were extended from 24 to 168 h with increasing concentrations of phosphine, conversely significant increase in mortality was greatly apparent during the initial treatment periods. PMID:26396434

  5. Phosphane-ene chemistry: the reactivity of air-stable primary phosphines and their compatibility with the thiol-ene reaction.

    PubMed

    Guterman, Ryan; Gillies, Elizabeth R; Ragogna, Paul J

    2015-09-21

    Air-sensitive and air-stable primary phosphines (RPH2) were compared for their ability to undergo photoinitiated phosphane-ene chemistry with 1-hexene. Despite their increased air-stability, the primary phosphines displayed equal to or greater reactivity when compared to air-sensitive alkyl or aryl analogues. The phosphane-ene reaction was also performed in the presence of 1-octanethiol to determine whether thiol-ene and phosphane-ene chemistries could proceed simultaneously. It was determined that the phosphane-ene process takes precedence over thiol-ene as P-H bond conversion was independent of thiol concentration. Tertiary phosphine (R3P) and some secondary phosphine (R2PH) products were found to react with thiols under experimental conditions to create phosphine-sulfides (P-S), but this chemistry only proceeded at low P-H bond concentrations. These results suggests that hydrogen transfer reactions take precedence over P-S formation and demonstrate the unique relationship between phosphane-ene and thiol-ene chemistry. PMID:26250862

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

    SciTech Connect

    Abatjoglou, A.G.; Peterson, R.R.; Bryant, D.R.

    1995-12-01

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

  7. A photoionization mass spectroscopic study on the formation of phosphanes in low temperature phosphine ices.

    PubMed

    Turner, Andrew M; Abplanalp, Matthew J; Chen, Si Y; Chen, Yu T; Chang, Agnes H H; Kaiser, Ralf I

    2015-10-14

    Isovalency rationalizes fundamental chemical properties of elements in the same group, but often fails to account for differences in the molecular structure due to the distinct atomic sizes and electron-pair repulsion of the isovalent atoms. With respect to main group V, saturated hydrides of nitrogen are limited to ammonia (NH3) and hydrazine (N2H4) along with ionic and/or metal-bound triazene (N3H5) and potentially tetrazene (N4H6). Here, we present a novel approach for synthesizing and detecting phosphanes formed via non-classical synthesis exploiting irradiation of phosphine ices with energetic electrons, subliming the newly formed phosphanes via fractionated sublimation, and detecting these species via reflectron time-of-flight mass spectrometry (ReTOF) coupled with vacuum ultraviolet (VUV) single photon ionization. This approach is able to synthesize, to separate, and to detect phosphanes as large as octaphosphane (P8H10), which far out-performs the traditional analytical tools of infrared spectroscopy and residual gas analysis via mass spectrometry coupled with electron impact ionization that could barely detect triphosphane (P3H5) thus providing an unconventional tool to prepare complex inorganic compounds such as a homologues series of phosphanes, which are difficult to synthesize via classical synthetic methods. PMID:26242769

  8. Complexes between dihydrogen and amine, phosphine, and arsine derivatives. Hydrogen bond versus pnictogen interaction.

    PubMed

    Grabowski, S?awomir J; Alkorta, Ibon; Elguero, José

    2013-04-18

    A theoretical study of the complexes between dihydrogen, H2, and a series of amine, phosphine, and arsine derivatives (ZH3 and ZH2X, with Z = N, P, or As and X = F, Cl, CN, or CH3) has been carried out using ab initio methods (MP2/aug-cc-pVTZ). Three energetic minima configurations have been characterized for each case with the H2 molecule in the proximity of the pnictogen atom (Z). In configuration A, the ?-electrons of H2 interact with ?-hole region of the pnictogen atom generated by the of X-Z bond. These complexes can be ascribed as pnictogen bonded. In configuration C, the lone electron pair of Z acts as the Lewis base, and H2 plays the role of the Lewis acid. Finally, configuration B presents a variety of noncovalent interactions depending on the binary complex considered. The atoms-in-molecules theory (AIM), natural bond orbitals (NBO) method as well as the density functional theory-symmetry adapted perturbation theory (DFT-SAPT) approach were used in this study to deepen the nature of the interactions considered. PMID:23514567

  9. Catalytic Oxidation of Alcohol via Nickel Phosphine Complexes with Pendant Amines

    SciTech Connect

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

    2014-09-05

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

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

    PubMed

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

    2013-04-01

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

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

    PubMed Central

    2012-01-01

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

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

    PubMed

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

    2015-01-01

    In order to compare the coordination properties of 1,4,7-triazacyclononane (tacn) derivatives bearing varying numbers of phosphinic/carboxylic acid pendant groups towards 68Ga, 1,4,7-triazacyclononane-7-acetic-1,4-bis(methylenephosphinic) acid (NOPA) and 1,4,7- triazacyclononane-4,7-diacetic-1-[methylene(2-carboxyethyl)phosphinic] acid (NO2AP) were synthesized using Mannich reactions with trivalent or pentavalent forms of H-phosphinic acids as phosphorus components. Stepwise protonation constants logK1-3 12.06, 3.90 and 1.95, and stability constants with GaIII and CuII, logKGaL 24.01 and logKCuL 16.66, were potentiometrically determined for NOPA. Both ligands were labelled with 68Ga and compared with NOTA (tacn-N,N',N?-triacetic acid) and NOPO, a TRAP-type [tacn-N,N',N?- tris(methylenephosphinic acid)] chelator. At pH 3, NOPO and NOPA showed higher labelling efficiency (binding with lower ligand excess) at both room temperature and 95 °C, compared to NO2AP and NOTA. Labelling efficiency at pH = 0-3 correlated with a number of phosphinic acid pendants: NOPO > NOPA > NO2AP > NOTA; however, it was more apparent at 95 °C than at room temperature. By contrast, NOTA was found to be labelled more efficiently at pH > 4 compared to the ligands with phosphinic acids. Overall, replacement of a single phosphinate donor with a carboxylate does not challenge 68Ga labelling of TRAP-type chelators. However, the presence of carboxylates facilitates labelling at neutral or weakly acidic pH. PMID:26197305

  13. Phosphine and methylphosphine production by simulated lightning—a study for the volatile phosphorus cycle and cloud formation in the earth atmosphere

    NASA Astrophysics Data System (ADS)

    Glindemann, Dietmar; Edwards, Marc; Schrems, Otto

    Phosphine (PH 3), was recently found worldwide even in the remote atmosphere (Naturwissenschaften83(1996a)131; Atmos. Environ. 37(2003)24 29). It is of interest to find natural mechanisms which could produce phosphine gas and drive a volatile link of the atmospheric phosphorus cycle and the formation of phosphoric acid as possible condensation nuclei for clouds. Here, we report on simulated lightning exposing sodium phosphate in a reducing medium (methane model atmosphere or organic matter) for 5 s to a spark induced by microwave. The gas product analyzed by gas chromatography contained phosphine (yield up to 0.6 g kg -1 phosphate P) and methylphosphine (CH 3)PH 2 (yield up to 0.02 g kg -1 phosphate P). We suggest a plasma-chemical formation mechanism where organic compounds or methane or secondary hydrogen thereof reduce phosphate to phosphine of which a small fraction can subsequently react with methyl radicals to form methylphosphine. A small yield of 6 mg phosphine per kg phosphate P was even obtained in methane free medium, by simple plasmatic recombination of inorganic phosphorus. We believe that methane and hydrogen are useful model substances of pyrolytic gases with high reducing power which may form if lightning strikes biomass, soil and aerosol. These results suggest evidence that phosphine and methylphosphine (detectable in the field by intense garlic odor) are produced when atmospheric lightning strikes the ground or aerosol which is containing oxidized forms of phosphorus and chemical reductants. Additional reviewed data show that laboratory lightning was able to reduce a much more significant portion of phosphate to phosphite (up to 25% yield), methylphosphonic acid (up to 8.5% yield) and traces of hypophosphite in a matter of seconds.

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

    PubMed

    Magnusson, R; Rittfeldt, L; Åstot, C

    2015-01-01

    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

  15. Transition Metal Complexes of Phosphinous Acids Featuring a Quasichelating Unit: Synthesis, Characterization, and Hetero-bimetallic Complexes.

    PubMed

    Allefeld, Nadine; Bader, Julia; Neumann, Beate; Stammler, Hans-Georg; Ignat'ev, Nikolai; Hoge, Berthold

    2015-08-17

    Diorganophosphane oxides were employed as preligands for the synthesis of catalytically active transition metal complexes of the phosphinous acids (CF3)2POH and (C2F5)2POH. Their reactions with solid PtCl2 and PdCl2 led to the formation of mononuclear phosphinous acid complexes [Cl2M{P(R(f))2OH}2] (M = Pd, Pt; R(f) = C2F5, CF3), which can be crystallized, for example, as its pyridinium salts, 2[HPy](+)[Cl2Pd{P(CF3)2O}2](2-). In vacuo HCl is liberated from the neutral palladium complexes affording mixtures of di- and polynuclear complexes. Moreover, (C2F5)2POH was reacted with several ?-diketonato complexes of palladium, platinum, and nickel yielding air- and moisture-stable complexes [(acac)M{[P(R(f))2O]2H}], featuring a quasichelating phosphinous acid phosphinito unit {P(R(f))2O···H···O(R(f))2P}(-). Treatment of [Ni(Cp)2] (Cp = cyclopentadienyl) and [(cod)RhCl]2 (cod = 1,5-cyclooctadiene) with (C2F5)2POH leads to the substitution of one Cp or chloro ligand by a quasichelating unit. The novel coordination compounds were characterized by NMR and IR spectroscopies, mass spectrometry, and X-ray diffraction analysis. The platinum complex [(acac)Pt{[P(C2F5)2O]2H}] (acac = acetylacetonato) was used for the construction of hetero-bimetallic complexes by the treatment with [(cod)RhCl]2 and [Ni(Cp)2]. The trinuclear bimetallic complex [{(acac)Pt[P(C2F5)2O]2}2Ni] is the first structurally characterized hetero-bimetallic species containing a bis(perfluoroalkyl)phosphinito bridge. PMID:26242286

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

    SciTech Connect

    Xue, Zhang; Kandala, Srikanth; Yang, Li; Watson, William H.; Wang, Xiaoping; Hrovat, David A.

    2011-01-01

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

  17. Insights into functional-group-tolerant polymerization catalysis with phosphine-sulfonamide palladium(II) complexes.

    PubMed

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

    2015-01-26

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

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

    PubMed Central

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

    2012-01-01

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

  19. Vinylarene/CO copolymerization and vinylarene/polar vinyl monomer/CO terpolymerization using palladium/phosphine-sulfonate catalysts.

    PubMed

    Kageyama, Takeharu; Ito, Shingo; Nozaki, Kyoko

    2011-02-01

    Palladium/phosphine-sulfonate complexes were effective for the alternating copolymerization of vinylarenes with carbon monoxide (CO). The obtained copolymers had iso-enriched microstructures with ll selectivity of up to circa 60%. The catalytic system was successfully applied to the terpolymerization of vinylarene and polar vinyl monomers with CO to produce novel terpolymers, which could not be obtained by using previously developed catalysts. NMR and DSC analyses suggested that vinylarene/CO units and polar vinyl monomer/CO units were randomly distributed in the terpolymer main chains. PMID:21254443

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

    DOEpatents

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

    1991-01-08

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

  1. Transcriptional inhibition of the Catalase gene in phosphine-induced oxidative stress in Drosophila melanogaster.

    PubMed

    Liu, Tao; Li, Li; Zhang, Fanhua; Wang, Yuejin

    2015-10-01

    Phosphine (PH3) is a toxic substance to pest insects and is therefore commonly used in pest control. The oxidative damage induced by PH3 is considered to be one of the primary mechanisms of its toxicity in pest insects; however, the precise mode of PH3 action in this process is still unclear. In this study, we evaluated the responses of several oxidative biomarkers and two of the main antioxidant enzymes, catalase (CAT) and superoxide dismutase (SOD), after fumigation treatment with PH3 in Drosophila melanogaster as a model system. The results showed that larvae exposed to sub-lethal levels of PH3 (0.028?mg/L) exhibited lower aerobic respiration rates and higher levels of hydrogen peroxide (H2O2) and lipid peroxidation (LPO). Furthermore, unlike SOD, the activity and expression of CAT and its encoding gene were downregulated by PH3 in a time- and dose-dependent manner. Finally, the responses of six potential transcription factors of PH3 were determined by real-time polymerase chain reaction to explore the regulation mechanism of DmCAT by PH3. There were no significant effects of PH3 on three nuclear factor-kappa B homologs (DORSAL, DIF, and RELISH) or two activator protein-1 genes (JUN and FOS), while dramatic inhibition of DNA replication-related element factor (DREF) expression was observed after fumigation with PH3, suggesting that PH3 could inhibit the expression of DmCAT via the DRE/DREF system. These results confirmed that PH3 induces oxidative stress and targets CAT by downregulating its encoding gene in Drosophila. Our results provide new insight into the signal transduction mechanism between PH3 and its target genes. PMID:26453223

  2. Evaluation of headspace solid-phase microextraction for analysis of phosphine residues in wheat.

    PubMed

    Ren, Yong Lin; Padovan, Benjamin; Desmarchelier, James M

    2012-01-01

    In headspace (HS) analysis, a fumigant is released from a commodity into a gas-tight container by grinding, heating, or microwaves. A new technique uses HS-solid-phase microextraction (SPME) for additional preconcentration of fumigant. HS-SPME was tested for detection of phosphine (PH3), chosen for examination because of its wide use on stored commodities. PH3 was applied to 50 g wheat in separate 250 mL sealed flasks, which were equipped either with a septum for conventional HS analysis or with one of four HS-SPME fibers [100 microm polydimethylsiloxane (PDMS), 85 microm carboxen (CAR)/PDMS, 75 microm CAR/PDMS, and 65 pm PDMS/divinylbenzene (DVB)]. The wheat was heated at 45 degrees C for 20 min. In conventional HS analysis, a gaseous aliquot (80 pL) was taken from the HS and injected into the GC instrument. In the HS-SPME procedure, the fiber was removed from the HS and exposed in the heated injection port of the GC instrument. In all cases, PH3 was determined under the same chromatographic conditions with a GC pulsed flame photometric detector. In a comparison of the efficacy of the fibers, the bipolar fibers (CAR/PDMS and PDMS/DVB) contained more PH3 than the aliquot in the conventional HS analysis; larger size bipolar fibers extracted PH3 more efficiently than smaller fibers (e.g., 85 > 75 > 65 microm). The nonpolar fiber (PDMS) contained no PH3. Four fortification levels of PH3 on wheat were tested: 0.01, 0.05, 0.1, and 0.3 microg/g. The response of each bipolar fiber increased with the fortification levels, but the conventional HS analysis detected no fumigant at the lowest fortification level of 0.01 mg/g. Under the conditions of the validation study, the LOD was in the range of 0.005-0.01 ng PH3/g wheat. PMID:22649943

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

    PubMed Central

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

    2015-01-01

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

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

    PubMed

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

    2015-12-01

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

  5. Developing five-membered heterocycle substituted phosphinous acids as ligands for palladium-catalyzed Suzuki-Miyaura and Catellani reactions.

    PubMed

    Chang, Ting-Wei; Ho, Pei-Yun; Mao, Kuo-Chung; Hong, Fung-E

    2015-10-21

    A new category of secondary phosphine oxides (SPOs) (5a-5j) with/without benzo-fused five-membered heterocyclic substituents were prepared. These new compounds are air- and moisture-stable ligands and have the advantage of long-term storage. Some of the ligands as well as ligand coordinated palladium complexes (6f' and 6f'') and platinum complexes (7b_trans & 7i_trans) were prepared and their structures were determined using single crystal X-ray diffraction methods. The crystal structure of 6f' revealed the formation of diamond shape di-palladium complexes with a Pd2Cl2 core. As for the structures of 7b_trans & 7i_trans, the processes for the generation of the trans-form of the bis-phosphine ligand coordinated platinum complexes are shown. These SPOs exhibit notable efficiencies in palladium-catalyzed Suzuki-Miyaura reactions. Moreover, organic compounds (9k and 10c) with unexpected conformations were obtained from Heck-type Catellani reactions. Reaction pathways are proposed to accommodate the probable routes for the formation of all organic products. PMID:26370178

  6. Synthesis and investigation of cobalt chalcogenide clusters with thienyl phosphine ligands as new acceptor materials for P3HT.

    PubMed

    Reeves, B J; Shircliff, D M; Shott, J L; Boardman, B M

    2015-01-14

    Cobalt selenide clusters with 2-bromo-5-diethylphosphinothiophene (1) and 2-bromo-5-diphenylphosphinothiophene (2) ligands are described. The phosphine ligands are obtained via lithium halogen exchange of 2,5-dibromothiophene followed by addition of chlorodiethylphosphine and chlorodiphenylphosphine, respectively. The prepared phosphine ligands are then sequentially reacted with elemental selenium followed by dicobalt octacarbonyl to yield Co6Se8(P(Et)2(C4H2SBr))6 (3) or Co6Se8(P(Ph)2(C4H2SBr))6 (4), respectively. The two new cobalt selenide clusters were characterized by UV-visible spectroscopy, Fourier-transform infrared spectroscopy, cyclic voltammetry, powder X-ray diffraction, and elemental analysis. Emission spectra were recorded for the addition of, Co6Se8(PEt3)6 (5), 3, and 4 to a 0.004 wt% solution of poly-3-hexyl thiophene (P3HT) in toluene to investigate the charge transport of the system. The quenching of the polymers' emission follows first-order like decay for each cluster. Clusters 3 and 4 are approximately twice as efficient at quenching the emission than cluster 5 with 4 being slightly more efficient than 3. Simple mixtures of 3, 4 or 5 and P3HT were spun cast from toluene into thin films and atomic force microscopy displayed relatively uniform dispersion of 3 and network-like formation of 4 in contrast to the phase separation of 5 in the polymer films. PMID:25388872

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

    PubMed Central

    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

    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

  8. Intramolecular C-H/O-H bond cleavage with water and alcohol using a phosphine-free ruthenium carbene NCN pincer complex.

    PubMed

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

    2014-12-15

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

  9. A facile phosphine-free colloidal synthesis of Cu2SnS3 and Cu2ZnSnS4 nanorods with a controllable aspect ratio.

    PubMed

    Wang, Jian-Jun; Liu, Pai; Ryan, Kevin M

    2015-09-18

    Cu2SnS3 (CTS) nanorods were synthesized with a controllable aspect ratio via a facile phosphine-free colloidal synthesis. This synthesis can be readily extended to obtain Cu2ZnSnS4 (CZTS) nanorods with tunable Zn content. PMID:26235602

  10. Tuning the depth of bowl-shaped phosphine hosts: capsule and pseudo-cage architectures in host-guest complexes with C60 fullerene.

    PubMed

    Yamamura, Masaki; Sukegawa, Kimiya; Nabeshima, Tatsuya

    2015-08-01

    Bowl-shaped phosphine molecules, whose bowl geometry can be controlled by a variation of the axial substituent, were synthesized, and used as host molecules to encapsulate C60. Host molecules with relatively shallow bowls formed a chiral capsule, while hosts with deeper bowls formed an achiral pseudo-cage. PMID:26120943

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

    SciTech Connect

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

    2011-03-07

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

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

    NASA Astrophysics Data System (ADS)

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

    1996-10-01

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

  13. REACTIONS OF {eta}{sup 5}-CYCLOPENTADIENYLCOBALT(III) ALKYLS WITH COBALT(I) PHOSPHINES AND IRON CARBONYLS. EVIDENCE FOR DIRECT {eta}{sup 5} -CYCLOPENTADIENYL AND TRIMETHYLPHOSPHINE GROUP TRANSFER BETWEEN METAL CENTERS

    SciTech Connect

    Bryndza, H.E.; Bergman, R.G.

    1980-08-01

    We have found that {eta}{sup 5}-methylcyclopentadienyl- (triphenylphosphine)dimethylcobalt(III) (1) undergoes intermolecular cyclopentadienyl ligand exchange with {eta}{sup 5}-cyclopentadienylbistriphenylphosphinecobalt(I). The unsubstituted cyclopentadienyl(triphenylphosphine)dimethylco-balt(III) undergoes exchange of phosphine for carbon monoxide with both Fe(CO){sub 4} and Fe(CO){sub 5} by two different mechanisms. The first involves electrophilic displacement of coordinated phosphine by unsaturated Fe(CO){sub 4} and the second takes place by electrophilic displacement of CO from Fe(CO){sub 5} by the unsaturated CpCoMe{sub 2} fragment (generated by phosphine dissociation from the saturated starting material).

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

    PubMed

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

    2007-12-01

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

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

    NASA Technical Reports Server (NTRS)

    Siochi, Emilie

    1995-01-01

    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.

  16. Hydrogen Peroxide and Di(hydroperoxy)propane Adducts of Phosphine Oxides as Stoichiometric and Soluble Oxidizing Agents.

    PubMed

    Ahn, Shin Hye; Cluff, Kyle J; Bhuvanesh, Nattamai; Blümel, Janet

    2015-11-01

    Aqueous hydrogen peroxide is widely used as an oxidizing agent in industry and academia. Herein, the hydrogen peroxide adducts of phosphine oxides, [tBu3 PO?H2 O2 ]2 and [Ph3 PO?H2 O2 ]2 ?H2 O2 , are described. Additionally, the corresponding di(hydroperoxy)propane adducts R3 PO?(HOO)2 CMe2 (R=Cy, Ph) were synthesized and characterized. All adducts could be obtained as large single crystals suitable for structural characterization by X-ray crystallography and solid-state NMR spectroscopy. The di(hydroperoxy)propane adducts are soluble in organic solvents which enables oxidation reactions in one phase. As the adducts are solid and molecular, they can easily be applied stoichiometrically. No loss of oxidizing power occurs upon long-term storage of the single crystals at room temperature or the powders at -20?°C. PMID:26457679

  17. Catalytic reduction of hydrazine to ammonia by a mononuclear iron(II) complex on a tris(thiolato)phosphine platform.

    PubMed

    Chang, Ya-Ho; Chan, Pooi-Mun; Tsai, Yi-Fang; Lee, Gene-Hsiang; Hsu, Hua-Fen

    2014-01-21

    To provide the mechanistic information of nitrogenase at a molecular level, much effort has been made to develop synthetic metal complexes that have enzyme-like reactivity. Herein we obtain an iron(II) complex binding with a tris(thiolato)phosphine ligand, [P(Ph)4][Fe(PS3?)(CH3CN)] [1; PS3? = P(C6H3-3-Me3Si-2-S)3(3-)] that catalyzes the reduction of hydrazine, an intermediate and a substrate of nitrogenase. The substrate- and product-bound adducts, [N(Bu)4][Fe(PS3?)(N2H4)] (2) and [N(Et)4][Fe(PS3?)(NH3)] (3), respectively, are also synthesized. This work provides the feasibility that the late stage of biological nitrogen fixation can be conducted at a single iron site with a sulfur-rich ligation environment. PMID:24377381

  18. Mechanistic studies on the formation of linear polyethylene chain catalyzed by palladium phosphine-sulfonate complexes: experiment and theoretical studies.

    PubMed

    Noda, Shusuke; Nakamura, Akifumi; Kochi, Takuya; Chung, Lung Wa; Morokuma, Keiji; Nozaki, Kyoko

    2009-10-01

    Linear polyethylene propagation starting from Pd phosphine-sulfonate complexes, Pd(CH(3))(L)(Ar(2)PC(6)H(4)SO(3)) (L = 2,6-lutidine, Ar = o-MeOC(6)H(4) (2a) and L = pyridine, Ar = Ph (2b)), was studied both experimentally and theoretically. Experimentally, highly linear polyethylene was obtained with Pd(CH(3))(L)(Ar(2)PC(6)H(4)SO(3)) complexes 2a and 2b. Formation of a long alkyl-substituted palladium complex (3) was detected as a result of ethylene oligomerization on a palladium center starting from methylpalladium complex. Additionally, well-defined ethyl and propyl complexes (6(Et) and 6(Pr)) were synthesized as stable n-alkyl palladium complexes. In spite of the existence of beta-hydrogens, the beta-hydride elimination to give 1-alkenes was very slow or negligible in all cases. On the other hand, isomerization of 1-hexene in the presence of a methylpalladium/phosphine-sulfonate complex 2a indicated that this catalyst system actually undergoes beta-hydride elimination and reinsertion to release internal alkenes. On the theoretical side, the relative energies were calculated for intermediates and transition states for chain-growth, chain-walking, and chain-transfer on the basis of the starting model complex Pd(n-C(3)H(7))(pyridine)(o-Me(2)PC(6)H(4)SO(3)) (8). First, cis/trans isomerization process via the Berry's pseudorotation was proposed for the Pd/phosphine-sulfonate system. The second oxygen atom of sulfonate group is involved in the isomerization process as the associative ligand, which is one of the most unique natures of the sulfonate group. Chain propagation was suggested to take place from the less stable alkylPd(ethylene) complex 10' with the TS of 27.4/27.7 ((E+ZPC)/G) kcal/mol. Possible beta-hydride elimination was suggested to occur under low concentration of ethylene: the highest-energy transition state to override for beta-hydride elimination was either >37.4/25.3 kcal/mol (TS(9-12)) or 29.1/27.4 kcal/mol (TS(8'-9') to reach 12'). The ethylene insertion to the iso-alkylpalladium species (14') is allowed via a TS of 28.6/29.1 kcal/mol (TS(14'-15')), slightly higher in energy than that for the normal-alkylpalladium species (TS(10'-11')). Easy chain transfer was suggested to proceed from the more stable PdH(olefin) complex 12' if beta-hydride elimination to 12' does take place. Thus, the production of linear polyethylene with high molecular weight under ethylene pressure suggests that the cis and trans PdH(alkene)(phosphine-sulfonate) complexes (12 and 12') are merely accessible in the presence of excess amount of ethylene. PMID:19746977

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

    SciTech Connect

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

    2006-06-01

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

  20. Solid-State (63)Cu, (65)Cu, and (31)P NMR Spectroscopy of Photoluminescent Copper(I) Triazole Phosphine Complexes.

    PubMed

    Yu, Huaguang; Tan, Xiuzhen; Bernard, Guy M; Terskikh, Victor V; Chen, Jinglin; Wasylishen, Roderick E

    2015-07-30

    The results of a solid-state (63/65)Cu and (31)P NMR investigation of several copper(I) complexes with functionalized 3-(2'-pyridyl)-1,2,4-triazole and phosphine ligands that have shown potential in the preparation of photoluminescent devices are reported. For each complex studied, distinct NMR parameters, with moderate (63)Cu nuclear quadrupolar coupling constant (CQ) values ranging from -17.2 to -23.7 MHz, are attributed to subtle variations in the distorted four-coordinate environments about the copper nuclei. The spans of the copper chemical shift (CS) tensors, ?11-?33, for the mono- and bisphosphine complexes are also similar, ranging from 1000 to 1150 ppm, but that for a complex with a strained bidentate phosphine ligand is only 650 ppm. The effects of residual dipolar and indirect spin-spin coupling arising from the (63/65)Cu- (31)P spin pairs, observed in the solid-state (31)P NMR spectra of these complexes, yield information about the orientations of the copper electric field gradient (EFG) tensors relative to the Cu-P bond. Variable-temperature (31)P NMR measurements for [Cu(bptzH)(dppe)]ClO4 (bptzH = 5-tert-butyl-3-(2'-pyridyl)-1,2,4-triazole; dppe = 1,2-bis(diphenylphosphino)ethane), undertaken to investigate the cause of the broad unresolved spectra observed at room temperature, demonstrate that the broadening arises from partial self-decoupling of the (63/65)Cu nuclei, a consequence of rapid quadrupolar relaxation. Ab initio calculations of copper EFG and CS tensors were performed to probe relationships between NMR parameters and molecular structure. The analysis demonstrated that CQ((63/65)Cu) is negative for all complexes studied here and that the largest components of the EFG tensors are generally coincident with ?11. PMID:26101890

  1. Molybdenum complexes supported by mixed NHC/phosphine ligands: activation of N2 and reaction with P(OMe)3 to the first meta-phosphite complex.

    PubMed

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

    2015-01-12

    Molybdenum(0) dinitrogen complexes, supported by the mixed NHC/phosphine pincer ligand PCP, exhibit an extreme activation of the N2 ligand due to a very ?-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

  2. A diphenyl ether derived bidentate secondary phosphine oxide as a preligand for nickel-catalyzed C-S cross-coupling reactions.

    PubMed

    Wellala, Nadeesha P N; Guan, Hairong

    2015-11-28

    A new bidentate secondary phosphine oxide (SPO) was synthesized from diphenyl ether via ortho-lithiation, phosphorylation with PhP(Cl)NEt2, and hydrolysis in an acidic medium. Nickel(0) species ligated with this new SPO was established as a more effective catalyst than Ni(0)-Ph2P(O)H for the cross-coupling of aryl iodides with aryl thiols. PMID:26456099

  3. Phosphine-catalyzed cascade [3 + 2] cyclization-allylic alkylation, [2 + 2 + 1] annulation, and [3 + 2] cyclization reactions between allylic carbonates and enones.

    PubMed

    Zhou, Rong; Wang, Jianfang; Song, Haibin; He, Zhengjie

    2011-02-18

    The phosphine-catalyzed annulations between Morita-Baylis-Hillman adduct carbonates and enones are reported. Under the catalysis of PBu(3) (20 mol %), cascade [3 + 2] cyclization-allylic alkylation, [2 + 2 + 1] annulation, and [3 + 2] cyclization reactions chemoselectively occur depending on the substituent variation of both the carbonate and enone. These reactions provide efficient syntheses of highly functionalized cyclopentenes and cyclopentanes. PMID:21235263

  4. Triphenyl­phosphine oxide–2-(4-hydroxy­benzen­yl)-4,4,5,5-tetra­methyl­imidazolidine-1-oxyl 3-oxide (1/1)

    PubMed Central

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

    2009-01-01

    The title compound, C18H15OP·C13H17N2O3, belongs to a series of mol­ecular systems based on triphenyl­phosphine oxide. The O atom of the oxide group acts as an acceptor for hydrogen bonds from –OH groups of the nitronyl nitroxide. The crystal structure is stabilized by O—H?O hydrogen bonds. PMID:21577899

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

    PubMed

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

    2009-01-01

    The title compound, C(18)H(15)OP·C(13)H(17)N(2)O(3), belongs to a series of mol-ecular systems based on triphenyl-phosphine oxide. The O atom of the oxide group acts as an acceptor for hydrogen bonds from -OH groups of the nitronyl nitroxide. The crystal structure is stabilized by O-H?O hydrogen bonds. PMID:21577899

  6. Utility of Bifunctional N-Heterocyclic Phosphine (NHP)-Thioureas for Metal-Free Carbon-Phosphorus Bond Construction toward Regio- and Stereoselective Formation of Vinylphosphonates.

    PubMed

    Mulla, Karimulla; Aleshire, Kyle L; Forster, Paul M; Kang, Jun Yong

    2016-01-01

    An efficient and practical protocol for completely regioselective and highly stereoselective synthesis of vinyldiazaphosphonates from N-heterocyclic phosphine (NHP) and allenes via phospha-Michael/intramolecular nucleophilic substitution reaction has been developed. This transformation enabled the synthesis of valuable densely functionalized vinyldiazaphosphonates with a ?-, ?-unsaturated ester moiety under mild reaction conditions. Synthetic utility of vinyldiazaphosphonates was demonstrated by a series of synthetic manipulations. PMID:26639442

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

    SciTech Connect

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

    2009-06-01

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

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

    PubMed

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

    2015-04-28

    The trigonal bipyramidal clusters M2Ir3(?-CO)3(CO)6(?(5)-C5H5)2(?(5)-C5Me4R) (M = Mo, R = Me 1a, 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 3a; M = Mo, R = Me, R? = (t)Bu 3b), 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 4a, H 4c; M = W, R = Me 4b, 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 2a, W 2b) with PPh3 afforded the mono-substitution products MIr4(?-CO)3(CO)6(PPh3)(?(5)-C5H5)(?(5)-C5Me5) (M = Mo 5a; M = W 5b), and further reaction of the molybdenum example 5a with excess PPh3 afforded the bis-substituted cluster MoIr4(?3-CO)2(?-CO)2(CO)4(PPh3)2(?(5)-C5H5)(?(5)-C5Me5) (6). Reaction of 1a with diphenylacetylene proceeded with alkyne coordination and C?C cleavage, affording Mo2Ir3(?4–?(2)-PhC2Ph)(?3-CPh)2(CO)4(?(5)-C5H5)2(?(5)-C5Me5) (7a) together with an isomer. Reactions of 2a and 2b with PhC?CR afforded MIr4(?3–?(2)-PhC2R)(?3-CO)2(CO)6(?(5)-C5H5)(?(5)-C5Me5) (M = Mo, R = Ph 8a; M = W, R = Ph 8b, H; M = W, R = C6H4(C2Ph)-3 9a, 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 3a, 4a–4c, 5b, 6, 7a, 8a, 8b and 9a were determined by single-crystal X-ray diffraction studies, establishing the core isomerization of 4, the site selectivity for ligand substitution in 3–6, the alkyne C?C dismutation in 7, and the site of alkyne coordination in 7–9. For clusters 3–6, 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 5 and 6 being the most reversible. For clusters 7–9, 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 8b 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

  9. In vitro antitumour activity of water soluble Cu(I), Ag(I) and Au(I) complexes supported by hydrophilic alkyl phosphine ligands.

    PubMed

    Santini, Carlo; Pellei, Maura; Papini, Grazia; Morresi, Barbara; Galassi, Rossana; Ricci, Simone; Tisato, Francesco; Porchia, Marina; Rigobello, Maria Pia; Gandin, Valentina; Marzano, Cristina

    2011-02-01

    Hydrophilic, monocationic [M(L)(4)]PF(6) complexes (M = Cu or Ag; L: thp = tris(hydroxymethyl)phosphine, L: PTA = 1,3,5-triaza-7-phosphaadamantane, L: thpp = tris(hydroxypropyl)phosphine) were synthesized by ligand exchange reaction starting from [Cu(CH(3)CN)(4)]PF(6) or AgPF(6) precursors at room temperature in the presence of an excess of the relevant phosphine. The related [Au(L)(4)]PF(6) complexes (L = thp, PTA or thpp) were synthesized by metathesis reactions starting from [Au(L)(4)]Cl at room temperature in the presence of equimolar quantity of TlPF(6). The three series of complexes [M(L)(4)]PF(6) were tested as cytotoxic agents against a panel of several human tumour cell lines also including a defined cisplatin resistant cell line. These investigations have been carried out in comparison with the clinically used metallodrug cisplatin and preliminary structure-activity relationships are presented. The best results in terms of in vitro antitumour activity were achieved with metal-thp species and, among the coinage metal complexes, copper derivatives were found to be the most efficient drugs. Preliminary studies concerning the mechanism of action of these [M(L)(4)]PF(6) species pointed to thioredoxin reductase as one of the putative cellular targets of gold and silver complexes and provided evidence that copper derivatives mediated their cytotoxic effect through proteasome inhibition. PMID:21194623

  10. Addition of Zn during the phosphine-based synthesis of indium phospide quantum dots: doping and surface passivation

    PubMed Central

    Vinokurov, Alexander A; Lebedev, Oleg I; Kuznetsova, Tatiana A; Dorofeev, Sergey G

    2015-01-01

    Summary Zinc-doped InP(Zn) colloidal quantum dots (QDs) with narrow size distribution and low defect concentration were grown for the first time via a novel phosphine synthetic route and over a wide range of Zn doping. We report the influence of Zn on the optical properties of the obtained quantum dots. We propose a mechanism for the introduction of Zn in the QDs and show that the incorporation of Zn atoms into the InP lattice leads to the formation of Zn acceptor levels and a luminescence tail in the red region of the spectra. Using photochemical etching with HF, we confirmed that the Zn dopant atoms are situated inside the InP nanoparticles. Moreover, doping with Zn is accompanied with the coverage of the QDs by a zinc shell. During the synthesis Zn myristate covers the QD nucleus and inhibits the particle growth. At the same time the zinc shell leads to an increase of the luminescence quantum yield through the reduction of phosphorous dangling bonds. A scenario for the growth of the colloidal InP(Zn) QDs was proposed and discussed. PMID:26114082

  11. Synergistic Effects of Oxygen on Phosphine and Ethyl Formate for the Control of Phthorimaea operculella (Lepidoptera: Gelechiidae).

    PubMed

    Kim, Hyun Kyung; Lee, Seon-Woo; Kim, Ju-Il; Yang, Jeong-Oh; Koo, Hyun-Na; Kim, Gil-Hah

    2015-12-01

    Phosphine (PH3) and ethyl formate (EF) are two potentially powerful postharvest fumigant insecticides. We investigated the effectiveness of both PH3 and EF as fumigants at all developmental stages of the potato tuber moth Phthorimaea operculella Zeller, and we also studied the synergistic effects of these fumigants under controlled atmospheres of 50 and 80% oxygen (O2). The larval stage of P. operculella was the most susceptible to fumigation with PH3 at both 5°C and 20°C. All of the developmental stages showed greater susceptibility to PH3 at 20°C than at 5°C, whereas the susceptibility of adult P. operculella to this fumigant was not affected by temperature. The toxicity of EF did not differ with temperature for any of the P. operculella developmental stages. The atmospheric oxidation of PH3 increased the toxicity of this fumigant toward all developmental stages at both temperatures. In contrast, no differences in toxicity were observed for oxidized EF compared with EF alone at any developmental stage. In conclusion, using fumigation tests, we showed that atmospherically oxidized PH3 was much more effective against P. operculella than PH3 alone, demonstrating a synergistic effect for this fumigant and O2. Therefore, treatment with PH3 and high concentrations of O2, as described in this study, could be useful for managing the postharvest pest P. operculella. PMID:26470389

  12. Addition of Zn during the phosphine-based synthesis of indium phospide quantum dots: doping and surface passivation.

    PubMed

    Mordvinova, Natalia E; Vinokurov, Alexander A; Lebedev, Oleg I; Kuznetsova, Tatiana A; Dorofeev, Sergey G

    2015-01-01

    Zinc-doped InP(Zn) colloidal quantum dots (QDs) with narrow size distribution and low defect concentration were grown for the first time via a novel phosphine synthetic route and over a wide range of Zn doping. We report the influence of Zn on the optical properties of the obtained quantum dots. We propose a mechanism for the introduction of Zn in the QDs and show that the incorporation of Zn atoms into the InP lattice leads to the formation of Zn acceptor levels and a luminescence tail in the red region of the spectra. Using photochemical etching with HF, we confirmed that the Zn dopant atoms are situated inside the InP nanoparticles. Moreover, doping with Zn is accompanied with the coverage of the QDs by a zinc shell. During the synthesis Zn myristate covers the QD nucleus and inhibits the particle growth. At the same time the zinc shell leads to an increase of the luminescence quantum yield through the reduction of phosphorous dangling bonds. A scenario for the growth of the colloidal InP(Zn) QDs was proposed and discussed. PMID:26114082

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

    NASA Astrophysics Data System (ADS)

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

    1994-01-01

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

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

    SciTech Connect

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

    2012-04-22

    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.

  15. Rotational resonance determination of the structure of an enzyme-inhibitor complex: Phosphorylation of an (aminoalkyl)phosphinate inhibitor of D-alanyl-D-alanine ligase by ATP

    SciTech Connect

    McDermott, A.E.; Creuzet, F.; Griffin, R.G. ); Zawadzke, L.E.; Ye, Qizhuang; Walsh, C.T. )

    1990-06-19

    The authors have used a newly developed solid-state NMR method, rotational resonance, to establish the structure of an inhibited complex formed upon reaction of D-alanyl-D-alanine ligase, ATP, and the aminoalkyl dipeptide analogue (1(S)-aminoethyl)(2-carboxy-2(R)-methyl-1-ethyl)phosphinic acid (Ib). Analogue Ib was determined to be an ATP-dependent, slow-binding inhibitor of the D-Ala-D-Ala ligase from Salmonella typhimurium, with an enzyme-inhibitor half-life of 17 days at 37{degree}C. The inhibited complex shows a {sup 31}P NMR spectrum which is very different from that which would arise from a mixture of the free inhibitor and ATP. Four well-resolved lines were observed. A rotational resonance the spectrum shows evidence for strong dipolar couplings between the phosphinate phosphorus and a phosphate ester species. The dipolar coupling between the phosphorus signals at 53 and {minus}3 ppm was measured at rotational resonance by use of numerical simulations of both the line shape of the signal and the profile of magnetization transfer between the two sites. The measured coupling, 1.0 {plus minus} 0.2 kHz, indicates that the two species are bridged in a P-O-P linkage, with a P-P through-space distance of 2.7 {plus minus} 0.2 {angstrom}. This proves that the mechanism of inactivation involves phosphorylation of the enzyme-bound inhibitor by ATP to form a phosphoryl-phosphinate adduct.

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

    PubMed Central

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

    2014-01-01

    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

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

    PubMed Central

    2013-01-01

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

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

    PubMed

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

    2015-01-01

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

  19. Chiral Platinum(II) Complexes Featuring Phosphine and Chloroquine Ligands as Cytotoxic and Monofunctional DNA-Binding Agents.

    PubMed

    Villarreal, Wilmer; Colina-Vegas, Legna; Rodrigues de Oliveira, Clayton; Tenorio, Juan C; Ellena, Javier; Gozzo, Fábio C; Cominetti, Marcia Regina; Ferreira, Antonio G; Ferreira, Marco Antonio Barbosa; Navarro, Maribel; Batista, Alzir A

    2015-12-21

    Chiral molecules in nature are involved in many biological events; their selectivity and specificity make them of great interest for understanding the behavior of bioactive molecules, by providing information about the chiral discrimination. Inspired by these conformational properties, we present the design and synthesis of novel chiral platinum(II) complexes featuring phosphine and chloroquine ligands with the general formula [PtCl(P)2(CQ)]PF6 (where (P)2 = triphenylphosphine (PPh3) (5), 1,3-bis(diphenylphosphine)propane (dppp) (6), 1,4-bis(diphenylphosphine)butane (dppb) (7), 1,1'-bis(diphenylphosphine)ferrocene (dppf) (8), and CQ = chloroquine] and their precursors of the type [PtCl2(P)2] are described. The complexes were characterized by elemental analysis, absorption spectroscopy in the infrared and ultraviolet-visible (UV-vis) regions, multinuclear ((1)H, (13)C, (31)P, (15)N, and (195)Pt) NMR spectroscopy, cyclic voltammetry, and mass spectrometry (in the case of chloroquine complexes). The interactions of the new platinum-chloroquine complexes with both albumin (BSA), using fluorescence spectroscopy, and DNA, by four widely reported methods were also evaluated. These experiments showed that these Pt-CQ complexes interact strongly with DNA and have high affinities for BSA, in contrast to CQ and CQDP (chloroquine diphosphate), which interact weakly with these biomolecules. Additional assays were performed in order to investigate the cytotoxicity of the platinum complexes against two healthy cell lines (mouse fibroblasts (L929) and the Chinese hamster lung (V79-4)) and four tumor cell lines (human breast (MDA-MB-231 and MCF-7), human lung (A549), and human prostate (DU-145)). The results suggest that the Pt-CQ complexes are generally more cytotoxic than the free CQ, showing that they are promising as anticancer drugs. PMID:26606142

  20. Generalized synthesis of metal phosphide nanorods via thermal decomposition of continuously delivered metal-phosphine complexes using a syringe pump.

    PubMed

    Park, Jongnam; Koo, Bonil; Yoon, Ki Youl; Hwang, Yosun; Kang, Misun; Park, Je-Geun; Hyeon, Taeghwan

    2005-06-15

    We synthesized uniform-sized nanorods of transition metal phosphides from the thermal decomposition of continuously delivered metal-phosphine complexes using a syringe pump. MnP nanorods with dimensions of 8 nm x 16 nm and 6 nm x 22 nm sized were synthesized by the thermal decomposition of Mn-TOP complex, which was prepared from the reaction of Mn(2)(CO)(10) and tri-n-octylphosphine (TOP), using a syringe pump with constant injection rates of 10 and 20 mL/h, respectively. When Co-TOP complex, which was prepared from the reaction of cobalt acetylacetonate and TOP, was reacted in a mixture solvent composed of octyl ether and hexadecylamine at 300 degrees C using a syringe pump, uniform 2.5 nm x 20 nm sized Co(2)P nanorods were generated. When cobaltocene was employed as a precursor, uniform Co(2)P nanorods with 5 nm x 15 nm were obtained. When Fe-TOP complex was added to trioctylphosphine oxide (TOPO) at 360 degrees C using a syringe pump and then allowed to age at 360 degrees C for 30 min, uniform-sized FeP nanorods with an average dimension of 12 nm x 500 nm were produced. Nickel phosphide (Ni(2)P) nanorods with 4 nm x 8 nm were synthesized successfully by thermally decomposing the Ni-TOP complex, which was synthesized by reacting acetylacetonate [Ni(acac)(2)] and TOP. We measured the magnetic properties of these nanorods, and some of the nanorods exhibited different magnetic characteristics compared to the bulk counterparts. PMID:15941277

  1. Growth of undoped indium phosphide by OMVPE in an inverted-vertical reactor using trimethylindium and tertiarybutylphosphine and phosphine

    SciTech Connect

    Parsons, J.D.; Oatis, K.; Wu, J.; Chaddha, A.K.; Hahn, S.R.; Chen, H.S.; Wild, S.; Deng, C. . Dept. of Electrical Engineering and Applied Physics); Plant, T.; Marlia, J. . Dept. of Electrical and Computer Engineering)

    1993-11-01

    The as-grown morphologies and background carrier concentrations of undoped InP epilayers grown at 650 C were determined as a function of phosphorus source [tertiarybutylphosphine (TBP) or phosphine (PH[sub 3])] and V:III ratio in an inverted-vertical (IV) metallorganic chemical vapor deposition (MOCVD) reactor. Specular surface morphology was obtained over the entire growth surface (16.6 cm[sup 2]) at a minimum PH[sub 3] to trimethylindium (TMIn) ratio of 10, and at a minimum TBP to TMIn ratio of 33. Below these V:III ratios, the area of the InP epilayer surfaces exhibiting specular morphology decreased as the V:III ratio was reduced; however, the layer thicknesses remained uniform. All undoped InP epilayers were n-type. The carrier concentration (N[sub d]-N[sub A]) obtained with PH[sub 3] in the specular area of the InP epilayers was on the order of 1.5 [times] 10[sup 14] cm[sup [minus]3] at V:III ratios up to ca. 20; at a V:III ratio of 40, N[sub D]-N[sub A] decreased to 10[sup 12] cm[sup [minus]3]. The carrier concentration obtained with TBP in the specular area of the InP epilayers was about 3.6 [times] 10[sup 15] cm[sup [minus]3] at V:III ratios up to 33. The relation of V:III ratio to morphology and the distribution of visible phosphorus deposition on the reactor tube walls during growth indicated that the decomposition characteristics of PH[sub 3] and TBP are considerably different in the inverted vertical reactor than in other system configurations. The decomposition characteristics observed here are empirically correlated with decomposition mechanism unique to the IV geometry.

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

    SciTech Connect

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

    2009-12-10

    We have demonstrated high-efficiency turquoise-blue electrophosphorescence from the complex Pt(ptp)2 = bis[3,5–bis(2–pyridyl)–1,2,4–triazolato]platinum(II) doped in the wide band-gap, ambipolar phosphine oxide host HM-A1 = 4-(diphenylphosphoryl)-N,N-diphenylaniline. For devices with 5% Pt(ptp)2 doping in HM-A1, we have achieved a peak external quantum efficiency and power efficiency of (11.8 ± 0.6) % and (61.2 ± 5.9) lm/W with high-pixel values of 13.1 % and 70.6 lm/W, respectively. These parameters maintained (10.6 ± 0.2) % and (40.3 ± 1.2) lm/W at a brightness of 1000 cd/m2 with high-pixel values of 10.8 % and 41.6 lm/W. Examination of several device structures suggests that the high performance is due to improved charge transport and exciton confinement in the emissive region. Devices with 1-10% doping concentration exhibit turquoise-blue emissions (?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.

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

    PubMed

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

    1996-01-17

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

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

    SciTech Connect

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

    1986-07-01

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

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

    PubMed Central

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

    2010-01-01

    Summary Because of the poor solubility of the commercially available bisacylphosphine oxides in dental acidic aqueous primer formulations, bis(3-{[2-(allyloxy)ethoxy]methyl}-2,4,6-trimethylbenzoyl)(phenyl)phosphine oxide (WBAPO) was synthesized starting from 3-(chloromethyl)-2,4,6-trimethylbenzoic acid by the dichlorophosphine route. The substituent was introduced by etherification with 2-(allyloxy)ethanol. In the second step, 3-{[2-(allyloxy)ethoxy]methyl}-2,4,6-trimethylbenzoic acid was chlorinated. The formed acid chloride showed an unexpected low thermal stability. Its thermal rearrangement at 180 °C resulted in a fast formation of 3-(chloromethyl)-2,4,6-trimethylbenzoic acid 2-(allyloxy)ethyl ester. In the third step, the acid chloride was reacted with phenylphosphine dilithium with the formation of bis(3-{[2-(allyloxy)ethoxy]methyl}-2,4,6-trimethylbenzoyl)(phenyl)phosphine, which was oxidized to WBAPO. The structure of WBAPO was confirmed by 1H NMR, 13C NMR, 31P NMR, and IR spectroscopy, as well as elemental analysis. WBAPO, a yellow liquid, possesses improved solubility in polar solvents and shows UV–vis absorption, and a high photoreactivity comparable with the commercially available bisacylphosphine oxides. A sufficient storage stability was found in dental acidic aqueous primer formulations. PMID:20502649

  6. Difluoro complexes of platinum(II) and -(IV) with monodentate phosphine ligands: an exceptional stability of d6 octahedral organometallic fluorides.

    PubMed

    Yahav, Anette; Goldberg, Israel; Vigalok, Arkadi

    2005-03-01

    Complexes (R3P)2PtF2 were prepared by reaction of the corresponding diiodo precursors with AgF in dichloromethane. The intermediate formation of trans- and cis-(R3P)2Pt(I)F was also observed. All fluoro complexes demonstrate a strong preference for the cis-configuration (R = Ph or Et) unless a bulky phosphine ligand is used (R = i-Pr), in which case the trans complex was observed. The Pt(IV) difluoro compounds (R3P)2Ar2PtF2 were obtained by reacting the Pt(II) diaryl precursors with XeF2. The fluoro ligands are located in the trans-position relative to the aryl groups in the overall octahedral environment. The representative Pt(II) and Pt(IV) difluoro complexes were characterized by X-ray crystallography. All fluoro compounds react rapidly with chlorotrimethylsilane to give the corresponding chloro complexes. The Pt(IV) difluorides are remarkably stable in the C-C reductive elimination reaction, relative to their dichloro analogs which reductively eliminate diaryl within several hours at 45 degrees C in N-methylpyrrolidone. It was found that phosphine dissociation from the octahedral Pt(IV) complex is essential for the reductive elimination reaction to take place, the difluoro complex being kinetically stable even at 60 degrees C. PMID:15732997

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

    PubMed

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

    2013-01-14

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

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

    PubMed

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

    2012-06-26

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

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

    PubMed

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

    2015-06-15

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

  10. Phosphine-Catalyzed Doubly Stereoconvergent ?-Additions of Racemic Heterocycles to Racemic Allenoates: The Catalytic Enantioselective Synthesis of Protected ?,?-Disubstituted ?-Amino Acid Derivatives.

    PubMed

    Kalek, Marcin; Fu, Gregory C

    2015-07-29

    Methods have recently been developed for the phosphine-catalyzed asymmetric ?-addition of nucleophiles to readily available allenoates and alkynoates to generate useful ?,?-unsaturated carbonyl compounds that bear a stereogenic center in either the ? or the ? position (but not both) with high stereoselectivity. The utility of this approach would be enhanced considerably if the stereochemistry at both termini of the new bond could be controlled effectively. In this report, we describe the achievement of this objective, specifically, that a chiral phosphepine can catalyze the stereoconvergent ?-addition of a racemic nucleophile to a racemic electrophile; through the choice of an appropriate heterocycle as the nucleophilic partner, this new method enables the synthesis of protected ?,?-disubstituted ?-amino acid derivatives in good yield, diastereoselectivity, and enantioselectivity. PMID:26192217

  11. Phosphine-Catalyzed Doubly Stereoconvergent ?-Additions of Racemic Heterocycles to Racemic Allenoates: The Catalytic Enantioselective Synthesis of Protected ?,?-Disubstituted ?-Amino Acid Derivatives

    PubMed Central

    2015-01-01

    Methods have recently been developed for the phosphine-catalyzed asymmetric ?-addition of nucleophiles to readily available allenoates and alkynoates to generate useful ?,?-unsaturated carbonyl compounds that bear a stereogenic center in either the ? or the ? position (but not both) with high stereoselectivity. The utility of this approach would be enhanced considerably if the stereochemistry at both termini of the new bond could be controlled effectively. In this report, we describe the achievement of this objective, specifically, that a chiral phosphepine can catalyze the stereoconvergent ?-addition of a racemic nucleophile to a racemic electrophile; through the choice of an appropriate heterocycle as the nucleophilic partner, this new method enables the synthesis of protected ?,?-disubstituted ?-amino acid derivatives in good yield, diastereoselectivity, and enantioselectivity. PMID:26192217

  12. Aspects of the cleavage of phosphines with potassium: Synthesis and reactivity of lithium and potassium bis(p-(dimethylamino)phenyl)phosphide

    SciTech Connect

    Toth, I.; Hanson, B.E.; Davis, M.E. )

    1990-03-01

    The cleavage of the triarylphosphines P(p-C{sub 6}H{sub 4}NMe{sub 2}){sub 3} and PhP(p-C{sub 6}H{sub 4}NMe{sub 2}){sub 2} with potassium in ether solvents was found to occur at room temperature. Cleavage of the mixed phosphine PhP(p-C{sub 6}H{sub 4}NMe{sub 2}){sub 2} was found to give a mixture of products that reflects the relative stability of the phosphides KP(Ph)(p-C{sub 6}H{sub 4}NMe{sub 2}) and KP(p-C{sub 6}H{sub 4}NMe{sub 2}){sub 2}. Cleavage with lithium resulted in the scrambling of the aryl groups so that the products LiPPh{sub 2} and P(Ph){sub 2}(p-C{sub 6}H{sub 4}NMe{sub 2}) also were obtained.

  13. Rhodium(III)-Catalyzed C-H Activation and Annulation with 1-Alkynylphosphine Sulfides: A Mild and Regioselective Access for the Synthesis of Bulky Phosphine Ligands.

    PubMed

    Li, Bin; Yang, Jie; Xu, Hong; Song, Haibin; Wang, Baiquan

    2015-12-18

    We reported herein rhodium(III)-catalyzed C-H activation and annulation reactions for the synthesis of bulky phosphine ligands by using 1-alkynylphosphine sulfides as key starting materials. In the presence of [Cp*RhCl2]2 (5 mol %) and CsOAc (2.0 equiv), various N-(pivaloyloxy)benzamides (3.0 equiv) could react smoothly with 1-alkynylphosphine sulfides at 40 °C in MeOH/CF3CH2OH cosolvent without external oxidant. Using [Cp(Ph)RhCl2]2 as catalyst, the reaction can be performed under less loading of benzamides (2.0 equiv) and milder reaction conditions (25 °C) with higher regioselectivity. In a sequential cyclization/desulfidation process, this new method provides a variety of bulky heteroarylphosphines with an isoquinolin-1(2H)-one motif. PMID:26595425

  14. Insertion of phosphinidene complexes into the P-H bond of secondary phosphine oxides: a new version of the phospha-Wittig synthesis of P[double bond, length as m-dash]C double bonds.

    PubMed

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

    2016-01-01

    Terminal phosphinidene complexes [RP-W(CO)5], as generated at 60 °C in the presence of copper chloride from the appropriate 7-phosphanorbornadiene complexes, react with secondary phosphine oxides Ar2P(O)H to give the insertion products into the P-H bonds. After metalation with NaH, these products react with aldehydes to give the corresponding phosphaalkenes which are trapped by dimethylbutadiene. PMID:26661055

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

    SciTech Connect

    Kessler, J.M.; Nelson, J.H. ); Frye, J.S. ); DeCian, A.; Fischer, J. )

    1993-03-17

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

  16. Cyclam Derivatives with a Bis(phosphinate) or a Phosphinato-Phosphonate Pendant Arm: Ligands for Fast and Efficient Copper(II) Complexation for Nuclear Medical Applications.

    PubMed

    David, Tomáš; Kubí?ek, Vojt?ch; Gutten, Ondrej; Lubal, P?emysl; Kotek, Jan; Pietzsch, Hans-Jürgen; Rulíšek, Lubomír; Hermann, Petr

    2015-12-21

    Cyclam derivatives bearing one geminal bis(phosphinic acid), -CH2PO2HCH2PO2H2 (H2L(1)), or phosphinic-phosphonic acid, -CH2PO2HCH2PO3H2 (H3L(2)), pendant arm were synthesized and studied as potential copper(II) chelators for nuclear medical applications. The ligands showed good selectivity for copper(II) over zinc(II) and nickel(II) ions (log KCuL = 25.8 and 27.7 for H2L(1) and H3L(2), respectively). Kinetic study revealed an unusual three-step complex formation mechanism. The initial equilibrium step leads to out-of-cage complexes with Cu(2+) bound by the phosphorus-containing pendant arm. These species quickly rearrange to an in-cage complex with cyclam conformation II, which isomerizes to another in-cage complex with cyclam conformation I. The first in-cage complex is quantitatively formed in seconds (pH ?5, 25 °C, Cu:L = 1:1, cM ? 1 mM). At pH >12, I isomers undergo nitrogen atom inversion, leading to III isomers; the structure of the III-[Cu(HL(2))] complex in the solid state was confirmed by X-ray diffraction analysis. In an alkaline solution, interconversion of the I and III isomers is mutual, leading to the same equilibrium isomeric mixture; such behavior has been observed here for the first time for copper(II) complexes of cyclam derivatives. Quantum-chemical calculations showed small energetic differences between the isomeric complexes of H3L(2) compared with analogous data for isomeric complexes of cyclam derivatives with one or two methylphosphonic acid pendant arm(s). Acid-assisted dissociation proved the kinetic inertness of the complexes. Preliminary radiolabeling of H2L(1) and H3L(2) with (64)Cu was fast and efficient, even at room temperature, giving specific activities of around 70 GBq of (64)Cu per 1 ?mol of the ligand (pH 6.2, 10 min, ca. 90 equiv of the ligand). These specific activities were much higher than those of H3nota and H4dota complexes prepared under identical conditions. The rare combination of simple ligand synthesis, very fast copper(II) complex formation, high thermodynamic stability, kinetic inertness, efficient radiolabeling, and expected low bone tissue affinity makes such ligands suitably predisposed to serve as chelators of copper radioisotopes in nuclear medicine. PMID:26615961

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

    PubMed

    Fu, Qiang; Yang, Limin; Wang, Qiuquan

    2007-06-15

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

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

    PubMed

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

    2012-11-21

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

  19. 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

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

    1987-09-02

    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.

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

    PubMed Central

    Chen, Su-Ching; Duan, Kow-Jen

    2015-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2006-01-01

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

  2. Kinetic and transport modeling of the metallorganic chemical vapor deposition of InP from trimethylindium and phosphine and comparison with experiments

    SciTech Connect

    Theodoropoulos, C.; Ingle, N.K.; Montziaris, T.J.; Chen, Z.Y.; Liu, P.L.; Kioseoglou, G.; Petrou, A.

    1995-06-01

    Gas phase and surface kinetic models describing the growth of InP by metallorganic chemical vapor deposition (MOCVD) using trimethylindium and phosphine diluted in hydrogen have been developed. A realistic model of the process was obtained by incorporating the kinetics into a two-dimensional transport model of the flow, heat, and mass transfer in horizontal MOCVD reactors. The unknown rate parameters of two surface growth reactions were estimated by comparing predicted growth rates of InP with the ones obtained from an atmospheric-pressure horizontal MOCVD reactor during heteroepitaxy of InP on GaAs. Sensitivity analysis of the reactions led to a reduced kinetic scheme, which can be used for predicting film growth rates with the same accuracy as a more detailed kinetic model, but with smaller computational requirements. The reduced kinetic model was subsequently tested against three sets of InP growth data reported in the literature and it successfully predicted observed growth rates and trends. Finally, parametric studies were performed on the computer to investigate the effects of changing the inlet velocity of the carrier gas, the operating pressure, and the inlet mole fraction of trimethylindium on the growth rate of the films. The proposed model may become a useful tool for reactor design, optimization, and scale-up of InP MOCVD.

  3. Effect of a novel selective and potent phosphinic peptide inhibitor of endopeptidase 3.4.24.16 on neurotensin-induced analgesia and neuronal inactivation

    PubMed Central

    Vincent, Bruno; Jiracek, Jirì; Noble, Florence; Loog, Mart; Roques, Bernard; Dive, Vincent; Vincent, Jean-Pierre; Checler, Frédéric

    1997-01-01

    We have examined a series of novel phosphinic peptides as putative potent and selective inhibitors of endopeptidase 3.4.24.16. The most selective inhibitor, Pro-Phe-?(PO2CH2)-Leu-Pro-NH2 displayed a Ki value of 12?nM towards endopeptidase 3.4.24.16 and was 5540 fold less potent on its related peptidase endopeptidase 3.4.24.15. Furthermore, this inhibitor was 12.5 less potent on angiotensin-converting enzyme and was unable to block endopeptidase 3.4.24.11, aminopeptidases B and M, dipeptidylaminopeptidase IV and proline endopeptidase. The effect of Pro-Phe-?(PO2CH2)-Leu-Pro-NH2, in vitro and in vivo, on neurotensin metabolism in the central nervous system was examined. Pro-Phe-?(PO2CHH2)-Leu-Pro-NH2 dose-dependently inhibited the formation of neurotensin 1-10 and concomittantly protected neurotensin from degradation by primary cultured neurones from mouse embryos. Intracerebroventricular administration of Pro-Phe-?(PO2CH2)-Leu-Pro-NH2 significantly potentiated the neurotensin-induced antinociception of mice in the hot plate test. Altogether, our study has established Pro-Phe-?(PO2CH2)-Leu-Pro-NH2 as a fully selective and highly potent inhibitor of endopeptidase 3.4.24.16 and demonstrates, for the first time, the contribution of this enzyme in the central metabolism of neurotensin. PMID:9208137

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

    PubMed

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

    2010-12-24

    Fumigants and volatile industrial chemicals are particularly hazardous to health when a freight container is fumigated or the contaminated material is introduced into its enclosed environment. Phosphine is now increasingly used as a fumigant, after bromomethane--the former fumigant of choice--has been banned by the Montreal Protocol. We have enhanced our previously established thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS) method by integrating a second gas chromatographic dimension and a flame photometric detector to allow the simultaneous detection of phosphine and volatile organic compounds (VOCs), providing a novel application. A thermal desorption system is coupled to a two dimensional gas chromatograph using both mass spectrometric and flame photometric detection (TD-2D-GC-MS/FPD). Additionally, the collection of mass spectrometric SIM and Scan data has been synchronised, so only a single analysis is now sufficient for qualitative scanning of the whole sample and for sensitive quantification. Though detection limits for the herewith described method are slightly higher than in the previous method, they are in the low ?L m(-3) range, which is not only below the respective occupational exposure and intervention limits but also allows the detection of residual contamination after ventilation. The method was developed for the separation and identification of 44 volatile substances. For 12 of these compounds (bromomethane, iodomethane, dichloromethane, 1,2-dichlorethane, benzene, tetrachloromethane, 1,2-dichloropropane, toluene, trichloronitromethane, ethyl benzene, phosphine, carbon disulfide) the method was validated as we chose the target compounds due to their relevance in freight container handling. PMID:21084090

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

    NASA Technical Reports Server (NTRS)

    Bosco, S. R.

    1982-01-01

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

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

    PubMed Central

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

    2010-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2011-05-01

    The new mononuclear Ru III complexes cis-, mer-[Ru( k3-dipic)(EPh 3) 2Cl]·2H 2O (E = P ( 1), As ( 2)), (L = 2,6-pyridyldicarboxylate; dipic) have been synthesized and characterized. The X-ray crystal structure of 1 reveals that the coordination geometry around the Ru III center is distorted octahedral in which three sites are occupied by tridentate dipic ligand and remaining three sites are occupied by two mutually cis triphenyl phosphine ligands and one chloride ions. In chloroform solvent, cis-, mer-[Ru( k3-dipic)(EPh 3) 2Cl]·2H 2O (E = P ( 1), As ( 2)) complexes undergoes thermal rearrangement to more stable trans-, mer-[Ru( k3-dipic)(EPh 3) 2Cl] (E = P( 3), As( 4)) complexes. Complexes 1 and 2 show rhombic EPR spectral features, while complex 3 and 4 show tetragonal distortion. The new Ru III complexes 1 and 2 display both Ru III-Ru II reduction and Ru III-Ru IV oxidation processes. These geometric isomers exhibit textbook differences both in spectroscopic as well as structural properties in the solid state. The new complexes 1 and 2 were found to catalyze the oxidation of alcohols to carbonyl derivatives using N-methyl morpholine- N-oxide as co-oxidant. The first static hyperpolarizability ( ?) 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).

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

    SciTech Connect

    Andersson, Gunther G. E-mail: vladimir.golovko@canterbury.ac.nz Al Qahtani, Hassan S.; Golovko, Vladimir B. E-mail: vladimir.golovko@canterbury.ac.nz; Alvino, Jason F.; Bennett, Trystan; Wrede, Oliver; Mejia, Sol M.; Metha, Gregory F. E-mail: vladimir.golovko@canterbury.ac.nz; Adnan, Rohul; Gunby, Nathaniel; Anderson, David P.

    2014-07-07

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

  9. Why did incorporation of acrylonitrile to a linear polyethylene become possible? Comparison of phosphine-sulfonate ligand with diphosphine and imine-phenolate ligands in the Pd-catalyzed ethylene/acrylonitrile copolymerization.

    PubMed

    Nozaki, Kyoko; Kusumoto, Shuhei; Noda, Shusuke; Kochi, Takuya; Chung, Lung Wa; Morokuma, Keiji

    2010-11-17

    Palladium-catalyzed coordination-insertion copolymerization of ethylene with acrylonitrile (AN) proceeded only by using phosphine-sulfonate (P-SO(3)) as a ligand among the neutral and anionic ligands we examined, those are phosphine-sulfonate (P-SO(3)), diphosphine (P-P), and imine-phenolate (N-O). In order to answer a question that is unique for P-SO(3), theoretical and experimental studies were carried out for the three catalyst systems. By comparing P-SO(3) and P-P, it was elucidated that (i) the ?-acrylonitrile complex [(L-L')PdPr(?-AN)] is less stable than the corresponding ?-complex [(L-L')PdPr(?-AN)] in both the phosphine-sulfonato complex (L-L' = P-SO(3)) and the diphosphine complex (L-L' = P-P) and (ii) the energetic difference between the ?-complex and the ?-complex is smaller in the P-SO(3) complexes than in the P-P complexes. Thus, the energies of the transition states for both AN insertion and its subsequent ethylene insertion relative to the most stable species [(L-L')PdPr(?-AN)] are lower for P-SO(3) than for P-P. The results nicely explain the difference between these two types of ligands. That is, ethylene insertion subsequent to AN insertion was detected for P-SO(3), while aggregate formation was reported for cationic [(L-L)Pd(CHCNCH(2)CH(3))] complex. Aggregate formation with the cationic complex can be considered as a result of the retarded ethylene insertion to [(L-L)Pd(CHCNCH(2)CH(3))]. In contrast, theoretical comparison between P-SO(3) and N-O did not show a significant energetic difference in both AN insertion and its subsequent ethylene insertion, implying that ethylene/AN copolymerization might be possible. However, our experiment using [(N-O)PdMe(lutidine)] complex revealed that ?-hydride elimination terminated the ethylene oligomerization and, more importantly, that the resulting Pd-H species lead to formation of free N-OH and Pd(0) particles. The ?-hydride elimination process was further studied theoretically to clarify the difference between the two anionic ligands, P-SO(3) and N-O. PMID:20973530

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

    NASA Astrophysics Data System (ADS)

    Bhattacharyya, Swarnendu; Dai, Zuyang; Domcke, Wolfgang

    2015-11-01

    A diabatic three-sheeted six-dimensional potential-energy surface has been constructed for the ground state and the lowest excited state of the PH3+ cation. Coupling terms of Jahn-Teller and pseudo-Jahn-Teller origin up to eighth order had to be included to describe the pronounced anharmonicity of the surface due to multiple conical intersections. The parameters of the diabatic Hamiltonian have been optimized by fitting the eigenvalues of the potential-energy matrix to ab initio data calculated at the CASSCF/MRCI level employing the correlation-consistent triple-? basis. The theoretical photoelectron spectrum of phosphine and the non-adiabatic nuclear dynamics of the phosphine cation have been computed by propagating nuclear wave packets with the multiconfiguration time-dependent Hartree method. The theoretical photoelectron bands obtained by Fourier transformation of the autocorrelation function agree well with the experimental results. It is shown that the ultrafast non-radiative decay dynamics of the first excited state of PH3+ is dominated by the exceptionally strong Jahn-Teller coupling of the asymmetric bending vibrational mode together with a hyperline of conical intersections with the electronic ground state induced by the umbrella mode. Time-dependent population probabilities have been computed for the three adiabatic electronic states. The non-adiabatic Jahn-Teller dynamics within the excited state takes place within ?5 fs. Almost 80% of the excited-state population decay to the ground state within about 10 fs. The wave packets become highly complex and delocalized after 20 fs and no further significant transfer of electronic population seems to occur up to 100 fs propagation time.

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

    PubMed

    Bhattacharyya, Swarnendu; Dai, Zuyang; Domcke, Wolfgang

    2015-11-21

    A diabatic three-sheeted six-dimensional potential-energy surface has been constructed for the ground state and the lowest excited state of the PH3 (+) cation. Coupling terms of Jahn-Teller and pseudo-Jahn-Teller origin up to eighth order had to be included to describe the pronounced anharmonicity of the surface due to multiple conical intersections. The parameters of the diabatic Hamiltonian have been optimized by fitting the eigenvalues of the potential-energy matrix to ab initio data calculated at the CASSCF/MRCI level employing the correlation-consistent triple-? basis. The theoretical photoelectron spectrum of phosphine and the non-adiabatic nuclear dynamics of the phosphine cation have been computed by propagating nuclear wave packets with the multiconfiguration time-dependent Hartree method. The theoretical photoelectron bands obtained by Fourier transformation of the autocorrelation function agree well with the experimental results. It is shown that the ultrafast non-radiative decay dynamics of the first excited state of PH3 (+) is dominated by the exceptionally strong Jahn-Teller coupling of the asymmetric bending vibrational mode together with a hyperline of conical intersections with the electronic ground state induced by the umbrella mode. Time-dependent population probabilities have been computed for the three adiabatic electronic states. The non-adiabatic Jahn-Teller dynamics within the excited state takes place within ?5 fs. Almost 80% of the excited-state population decay to the ground state within about 10 fs. The wave packets become highly complex and delocalized after 20 fs and no further significant transfer of electronic population seems to occur up to 100 fs propagation time. PMID:26590531

  12. Cu(I) complexes bearing the new sterically demanding and coordination flexible tris(3-phenyl-1-pyrazolyl)methanesulfonate ligand and the water-soluble phosphine 1,3,5-triaza-7-phosphaadamantane or related ligands.

    PubMed

    Wanke, Riccardo; Smole?ski, Piotr; da Silva, M Fátima C Guedes; Martins, Luísa M D R S; Pombeiro, Armando J L

    2008-11-01

    The new sterically hindered scorpionate tris(3-phenylpyrazolyl)methanesulfonate (Tpms(Ph))(-) has been synthesized and its coordination behavior toward a Cu(I) center, in the presence of 1,3,5-triaza-7-phosphaadamantane (PTA), N-methyl-1,3,5-triaza-7-phosphaadamantane tetraphenylborate ((mPTA)[BPh4]) or hexamethylenetetramine (HMT) has been studied. The reaction between Li(Tpms(Ph)) (1) and [Cu(MeCN)4][PF6] yields [Cu(Tpms(Ph))(MeCN)] (2) which, upon further acetonitrile displacement on reaction with PTA, HMT, or (mPTA)[BPh4], gives the corresponding complexes [Cu(Tpms(Ph))(PTA)] (3), [Cu(Tpms(Ph))(HMT)] (4), and [Cu(Tpms(Ph))(mPTA)][PF6] (5). All the compounds have been characterized by (1)H, (31)P, (13)C, COSY or HMQC-NMR, IR, elemental analysis, and single crystal X-ray diffraction. In the complexes (3) and (5), which bear a phosphine ligand (i.e., PTA and mPTA, respectively), the new scorpionate ligand shows the typical N, N, N-coordination mode, whereas in (2) and (4), bearing a N-donor ligand (i.e., MeCN and HMT, respectively), it binds the metal via the N,N,O chelating mode, involving the sulfonate moiety. PMID:18841929

  13. Palladium-catalyzed desulfitative Mizoroki-Heck couplings of sulfonyl chlorides with mono- and disubstituted olefins: rhodium-catalyzed desulfitative heck-type reactions under phosphine- and base-free conditions.

    PubMed

    Dubbaka, Srinivas Reddy; Vogel, Pierre

    2005-04-22

    New conditions have been found for the desulfitative Mizoroki-Heck arylation and trifluoromethylation of mono- and disubustituted olefins with arenesulfonyl and trifluoromethanesulfonyl chlorides. Thus (E)-1,2-disubstituted alkenes with high stereoselectivity and 1,1,2-disubstituted alkenes with 12:1 to 21:1 E/Z steroselectivity can be obtained. Herrmann's palladacycle at 0.1 mol % is sufficient to catalyze these reactions, for which electron-rich or electron-poor sulfonyl chlorides and alkenes are suitable. If phosphine- and base-free conditions are required, 1 mol % [RhCl(C(2)H(4))(2)] catalyzes the desulfitative cross-coupling reactions. Contrary to results reported for [RuCl(2)(PPh(3))(2)]-catalyzed coupling reactions with sulfonyl chlorides, the palladium and rhodium desulfitative Mizoroki-Heck coupling reactions are not inhibited by radical scavenging agents. Possible sulfones arising from the sulfonylation of alkenes at 60 degrees C are not desulfitated at higher temperatures in the presence of the Pd or Rh catalysts. PMID:15593242

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

    PubMed

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

    2014-11-17

    Three isomers of a new heteroditopic ligand that contains a di(1H-pyrazolyl)methyl (-CHpz2) moiety connected to a di(p-tolyl)phosphine group via a para-, meta-, or ortho-phenylene spacer (pL, mL, and oL, respectively) have been synthesized by using a palladium(0)-catalyzed coupling reaction between HP(p-tolyl)2 and the appropriate isomer of (IC6H4)CHpz2. The 1:1 complexes of silver(I) trifluoromethanesulfonate, Ag(OTf), were prepared to examine the nature of ligand coordination and the type of supramolecular isomer (monomeric, cyclic oligomeric, or polymeric) that would be obtained. The single crystal X-ray diffraction studies showed that [Ag(pL)](OTf), 1, and [Ag(mL)](OTf), 2, possessed cyclic dimeric dications, whereas [Ag(oL)](OTf), 3, was a coordination polymer. The polymeric chain in 3 could be disrupted by reaction with triphenylphosphine, and the resulting complex, [Ag(oL)(PPh3)](OTf), 4, possessed a monometallic cation where the ligand was bound to silver in a chelating ?(2)P,N- coordination mode. The solution structures of 1-4 were probed via a combination of IR, variable-temperature multinuclear ((1)H, (13)C, (31)P) NMR spectroscopy, as well as by electron spray ionization (ESI)(+) mass spectrometry. A related complex [Ag(m-IC6H4CHpz2)2](OTf), 5, was also prepared, and its solid-state and solution spectroscopic properties were studied for comparison purposes. These studies suggest that the cyclic structures of 1 and 2 are likely preserved but are dynamic in solution at room temperature. Moreover, both 3 and 4 have dynamic solution structures where 3 is likely extensively dissociated in CH3CN or acetone rather than being polymeric as in the solid state. PMID:25375040

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

    SciTech Connect

    Shido, Takafumi; Okazaki, Takumi; Ichikawa, Masaru

    1995-12-01

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

  16. Biological evaluation of thrombus imaging agents utilizing water soluble phosphines and tricine as coligands when used to label a hydrazinonicotinamide-modified cyclic glycoprotein IIb/IIIa receptor antagonist with 99mTc.

    PubMed

    Barrett, J A; Crocker, A C; Damphousse, D J; Heminway, S J; Liu, S; Edwards, D S; Lazewatsky, J L; Kagan, M; Mazaika, T J; Carroll, T R

    1997-01-01

    A hydrazinonicotinamide-functionalized cyclic glycoprotein IIb/IIIa (GPIIb/IIIa) receptor antagonist [cyclo(D-Val-NMeArg-Gly-Asp-Mamb(5-(6-(6-hydrazinonicotin amido)hexanamide))) (HYNICtide)] was labeled with 99mTc using tricine and a water soluble phosphine [trisodium triphenylphosphine-3,3',3"-trisulfonate (TPPTS); disodium triphenylphosphine-3,3'-disulfonate (TPPDS); or sodium triphenylphosphine-3-monosulfonate (TPPMS)] as coligands. Three complexes, [99mTc(HYNICtide)(L)(tricine)] (1, L = TPPTS; 2, L = TPPDS; 3, L = TPPMS), were evaluated in the canine arteriovenous shunt (AV shunt) model and canine deep vein thrombosis imaging (DVT) model. All three agents were adequately incorporated into the arterial and venous portions of the growing thrombus (7.8-9.9 and 0.2-3.7% ID/g, respectively) in the canine AV shunt model. In the canine DVT model all three complexes had thrombus uptake that far exceeded the negative control, [99mTc]albumin. The findings indicate similar incorporation into a venous thrombus (% ID/g = 2.86 +/- 0.4, 3.4 +/- 0.9, and 3.38 +/- 1.1 for complexes 1, 2, and 3, respectively) and similar blood clearance with a t1/2 of approximately 90 min. Gamma camera scintigraphy allowed visualization of deep vein thrombosis in as little as 15 min with the thrombus/muscle ratios being 3.8 +/- 0.8, 2.8 +/- 0.4, and 3.0 +/- 0.8 for complexes 1, 2, and 3, respectively. The visualization of the thrombus improved over time, and the thrombus/muscle ratios were 9.7 +/- 1.9, 13.8 +/- 3.6, and 9.4 +/- 2 for complexes 1, 2, and 3, respectively, at 120 min postinjection. The administration of complexes 1-3 did not alter platelet function, hemodynamics, or the coagulation cascade. Furthermore, complexes 1-3 did not significantly differ in their uptake into the growing thrombus, blood clearance, and target to background ratios. Therefore, all three complexes have the capability to detect rapidly growing venous and arterial thrombi. PMID:9095355

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

    SciTech Connect

    de Vries, N.; Cook, J.; Davison, A. ); Jones, A.G. )

    1991-06-12

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

  18. Systematization of published data on phosphine isotopologues

    NASA Astrophysics Data System (ADS)

    Akhlestin, A. Y.; Voronina, S. S.; Privezentsev, A. I.; Fazliev, A. Z.

    2012-11-01

    This is a continuation of a series of papers on the systematization of spectroscopic information on a number of atmospheric molecules (H2O [1], H2S [2], NH3 [3], CO2 [4], etc). The purpose of this work is to develop a database and a knowledge base of phospine isotopologues. The data imported from publications are validated. The technical aspect of the systematization implies its representation in the form of ontology (logical theory) that provides an automatic check for the consistency of classes and class attribution of individuals. Individuals in the knowledge base describe the properties of the published spectral line parameters.

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

    E-print Network

    Barder, Timothy E

    2007-01-01

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

  20. 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)

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

    2012-06-01

    An extractive spectrophotometric analytical method has been developed for the determination of uranium in ore leach solution. This technique is based on the selective extraction of uranium from multielement system using a synergistic mixture of 2-ethylhexyl phosphonic acid-mono-2-ethylhexyl ester (PC88A) and tri-n-octyl phosphine oxide (TOPO) in cyclohexane and color development from the organic phase aliquot using 2-(5-Bromo-2-pyridylazo)-5-diethyl aminophenol (Br-PADAP) as chromogenic reagent. The absorption maximum (?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.

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

    NASA Astrophysics Data System (ADS)

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

    2011-09-01

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

  2. 40 CFR 180.225 - Phosphine; tolerances for residues.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

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

  3. 40 CFR 180.225 - Phosphine; tolerances for residues.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

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

  4. 40 CFR 180.225 - Phosphine; tolerances for residues.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

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

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

    Code of Federal Regulations, 2011 CFR

    2011-07-01

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

  6. 40 CFR 180.225 - Phosphine; tolerances for residues.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

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

  7. & Surfaces and Interfaces Structures and Unexpected Dynamic Properties of Phosphine

    E-print Network

    Bluemel, Janet

    of warfare agents.[3] Another long-stand- ing question in the field of immobilized catalysts[4] is whether of adsorbed metallocenes.[9] Figure 1. 31 P MAS NMR spectra of polycrystalline Ph3PO (bottom) and Ph3PO

  8. Phosphine-Free EWG-Activated Ruthenium Olefin Metathesis Catalysts

    NASA Astrophysics Data System (ADS)

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

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

  9. Crystal structure of tert-butyl­diphenyl­phosphine oxide

    PubMed Central

    Agbeworvi, George; Assefa, Zerihun; Sykora, Richard E.; Taylor, Jared D.

    2015-01-01

    In the structure of the title triorganophosphine oxide, C16H19OP, the P—O bond is 1.490?(1)?Å. The P atom has a distorted tetrahedral geometry. The O atom inter­acts with both phenyl groups of a neighboring mol­ecule [C?O = 2.930?(3) and 2.928?(4)?Å]. The C—O interaction directs an extended supramolecular arrangement along the a-axis. PMID:26090188

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

    E-print Network

    Freiberg, Evan, 1974-

    2001-01-01

    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 ...

  11. 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 ...

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

    ERIC Educational Resources Information Center

    Faust, Kristen E.; Storhoff, Bruce N.

    1989-01-01

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

  13. DNA Alkylation by Leinamycin Can Be Triggered by Cyanide and Phosphines

    E-print Network

    Gates, Kent. S.

    - cycle.1,2 Reaction of thiols with this sulfur heterocycle in leinamycin initiates chemistry that leads-independent pathway initiated by hydrolysis of leinamycin's sulfur heterocycle (Scheme 1).8,9 Although hydrolytic nucleophiles might react with leinamycin's electro- philic sulfur heterocycle in a manner similar to thiols

  14. A Phosphine-Coordinated Boron-Centered Gomberg-Type Radical.

    PubMed

    Rosenthal, Amos J; Devillard, Marc; Miqueu, Karinne; Bouhadir, Ghenwa; Bourissou, Didier

    2015-08-01

    The P-coordinated boryl radical [Ph2P(naphthyl)BMes]? (Mes=mesityl) was prepared by (electro)chemical reduction of the corresponding borenium salt or bromoborane. Electron paramagnetic resonance (EPR) analysis in solution and DFT calculations indicate large spin density on boron (60-70%) and strong P-B interactions (P?B ??donation and B?P negative hyperconjugation). The radical is persistent in solution and participates in a Gomberg-type dimerization process. The associated quinoid-type dimer has been characterized by single-crystal X-ray diffraction. PMID:26118986

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

    E-print Network

    Lee, Sarah Yunmi

    2014-01-01

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

  16. Luminescence in phosphine-stabilized copper chalcogenide cluster molecules--a comparative study.

    PubMed

    Eichhöfer, Andreas; Buth, Gernot; Lebedkin, Sergei; Kühn, Michael; Weigend, Florian

    2015-10-01

    The electronic properties of a series of eight copper chalcogenide clusters including [Cu12S6(dpppt)4] (dpppt = Ph2P(CH2)5PPh2), [Cu12Se6(dppo)4] (dppo = Ph2P(CH2)8PPh2), [Cu12S6(dppf)4] (dppf = Ph2PCpFeCpPPh2), [Cu12S6(PPh2Et)8], [Cu12S6(PEt3)8], [Cu24S12(PEt2Ph)12], [Cu20S10(PPh3)8], and [Cu20S10(P(t)Bu3)8] were investigated by absorption and photoluminescence (PL) spectroscopy as well as time-dependent density functional theory calculations. Major features of the experimental electronic absorption spectra are generally well-reproduced by the spectra simulated from the calculated singlet transitions. Visualization of the nonrelaxed difference densities indicates that for all compounds transitions at higher energies (above ?2.5 eV, i.e., below ?495 nm) predominantly involve excitations of electrons from orbitals of the cluster core to ligand orbitals. Conversely, the natures of the lower-energy transitions are found to be highly sensitive to the specifics of the ligand surface. Bright red PL (centered at ?650-700 nm) in the solid state at ambient temperature is found for complexes with all 'Cu12S6' (E = S, Se) cores as well as the dimeric 'Cu24S12', although in [Cu12S6(dppf)4], the PL appears to be efficiently quenched by the ferrocenyl groups. Of the two isomeric 'Cu20S10' complexes the prolate cluster [Cu20S10(PPh3)8] shows a broad emission that is centered at ?820 nm, whereas the oblate cluster [Cu20S10(P(t)Bu3)8] displays a relatively weak orange emission at ?575 nm. The emission of all complexes decays on the time scale of a few microseconds at ambient temperature. A very high photostability is quantitatively estimated for the representative complex [Cu12S6(dpppt)4] under anaerobic conditions. PMID:26378617

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

    PubMed

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

    2014-07-01

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

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

    PubMed

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

    2015-06-01

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

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

    ERIC Educational Resources Information Center

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

    2010-01-01

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

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

    PubMed

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

    2015-06-01

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

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

    SciTech Connect

    Jones, W.D.; Dong, L.; Myers, A.W. )

    1995-02-01

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

  2. A thiosemicarbazone ligand functionalized by a phosphine group: reactivity toward coinage metal ions.

    PubMed

    Castiñeiras, Alfonso; Pedrido, Rosa

    2010-04-21

    The reactivity of the phosphino-thiosemicarbazone ligand 2-(2-(diphenylphosphino)benzylidene)-N-ethylthiosemicarbazone (HLPEt) toward M(I) halides (M = Cu, Ag, Au) was studied. The complexes obtained, with formulae [Cu(HLPEt)(2)]Br (1), [Cu(HLPEt)(2)]I.2H(2)O (2), [Ag(HLPEt)(LPEt)].3H(2)O (3), [Au(2)(HLPEt)(2)Cl]Cl.CH(3)OH (4) were satisfactorily characterized by elemental analysis, IR, ESI and (1)H/(31)P NMR. Moreover, we have obtained the crystal structure of the ligand HLPEt and its sulfide oxidized form HLP(S)Et, which represents a new case of desulfurization process in thiosemicarbazone ligands. In addition, we present the crystal structure of the complexes 1 + H(2)O + 3MeOH and [Au(2)(HLPEt)(4)Cl]Cl.3CH(3)OH (5), together with their interesting crystal packing. The complex 5 is an interesting case of a pseudo-chloronium gold(I) complex. The ligand HLPEt and the complexes 3 and 4 display intense luminescence at room temperature. PMID:20354611

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

    SciTech Connect

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

    2014-04-01

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

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

    SciTech Connect

    Coburn, M.D.

    1987-01-01

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

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

    EPA Science Inventory

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

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

    PubMed

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

    2015-07-20

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

  7. Palladium/Tris(tert-butyl)phosphine-Catalyzed Suzuki Cross-Couplings in the Presence of Water

    E-print Network

    Lou, Sha

    Dipalladiumtris(dibenzylideneacetone)/tris(tert-butyl)phosphonium tetrafluoroborate/potassium fluoride dihydrate [Pd2(dba)3/[HP(t-Bu)3]BF4/KF?2?H2O] serves as a mild, robust, and user-friendly method for the efficient ...

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

    PubMed

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

    2014-06-01

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

  9. Vibrational spectra and structural dynamic models of arsine-and phosphine-substituted biphenyl

    NASA Astrophysics Data System (ADS)

    Élkin, P. M.; Pulin, V. F.; Dzhalmuhambetova, E. A.

    2008-07-01

    Vibrational spectra of biphenylarsine, biphenylphosphine, biphenyldichloroarsine, and biphenyldichlorophosphine are analyzed by the DFT/B3LYP/6-31G(d) method. The fundamental vibrations of these compounds were interpreted based on direct quantum calculations of the geometrical and electronic structure in the anharmonic approximation. Solving the problem in the anharmonic approximation avoids the necessity of using a scaling procedure in predictive calculations.

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

    PubMed

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

    2013-01-01

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

  11. Radical synthesis of trialkyl, triaryl, trisilyl and tristannyl phosphines from P?

    E-print Network

    Cummins, Christopher C.

    A reaction scheme has been devised according to 3 RX + 3 Ti(III) + 0.25 P? ? PR? + 3 XTi(IV), wherein RX = PhBr, CyBr, Me?SiI or Ph?SnCl, with contrasting results in the case of more hindered RX. The scheme accomplishes ...

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

    E-print Network

    Sinisi, Riccardo

    Because carbonyl groups are ubiquitous in organic chemistry, the ability to synthesize functionalized carbonyl compounds, particularly enantioselectively, is an important objective. We have developed a straightforward and ...

  13. (2-{[2-(diphenyl­phosphino)phen­yl]thio}­phen­yl)diphenyl­phosphine sulfide

    PubMed Central

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

    2012-01-01

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

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

    E-print Network

    Jones, William D.

    Mechanistic Investigation of Catalytic Carbon-Carbon Bond Activation and Formation by Platinum impede their development. First, the metal- carbon bond resulting from C-C insertion has been calculated Of this latter variety, Milstein and co-workers have discovered a system that is capable of removing a methyl

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

    E-print Network

    the thiol leaves hydrophilic moieties exposed to the environment; these can be used to promote water) Murray, C. D.; Kagan, C. R.; Bawendi, M. G. Annu. ReV. Mater. 2000, 30, 545. (c) Sanchez, C.; Soler

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

    E-print Network

    Sun, Jianwei

    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 ...

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

    NASA Astrophysics Data System (ADS)

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

    2014-04-01

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

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

    PubMed Central

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

    2014-01-01

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

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

    PubMed

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

    2013-02-14

    The cyclic peptide gramicidin S was used as a rigid template to provide novel peptide-based bisphosphine ligands for transition metal catalysis. Two bisphosphine-coordinated Rh(I) complexes allowed asymmetric hydrogenation with 10-52% ee and the corresponding Pd(II) analogues catalysed asymmetric allylic alkylation with 13-15% ee. PMID:23235486

  20. Nucleophilic Substitution Reactions Using Phosphine Nucleophiles: An Introduction to Phosphorus-31 NMR

    ERIC Educational Resources Information Center

    Sibbald, Paul A.

    2015-01-01

    Nuclear magnetic resonance (NMR) spectroscopy is commonly used in modern synthetic chemistry to monitor the conversion of reactants to products. Since instruction in the use of NMR spectroscopy typically does not occur until after the introduction of nucleophilic substitution reactions, organic chemistry students are not able to take advantage of…

  1. Thioiminium and thiaphospholanium derived from acetonitrile via nickel(ii)-(2-mercaptophenyl)phosphine complexation.

    PubMed

    Chang, Hao-Ching; Hsu, Yu-Chen; Chen, Chia-Hui; Kuo, Ting-Shen; Lee, Way-Zen

    2015-12-28

    [Ni(P(o-C6H4S)(o-C6H4SC(CH3)[double bond, length as m-dash]NH2)(C6H5))2](ClO4)2 (2) with two thioiminium functionalities is derived from CH3CN solvent under anhydrous conditions. Moreover, thiaphospholanium salts, [(C6H5)P(C6H4SC(CH3)(NHCOCH3))(o-C6H4SH)](ClO4) (3) and [(C6H5)2-P(C6H4SC(CH3)(NH3))](ClO4)2 (5), can be obtained through a similar Pinner-type nitrile activation. These results demonstrate the possible intermediate of enzymatic nitrile transformation and also provide an approach to the preparation of 2-amino-1,3-benzothiaphospholanium derivatives. PMID:26549142

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

    PubMed

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

    2006-05-21

    In ongoing attempts of directed synthesis of high-nuclearity Au-Pt carbonyl/phosphine clusters with [Ni6(CO)12]2- used as reducing agent and CO source, we have isolated and characterized two new closely related variable-stoichiometric trimetallic clusters, Pt3(Pt(1-x)Ni(x))(AuPPh3)2(mu2-CO)4(CO)(PPh3)3 (1) and Pt2(Pt(2-y)Ni(y))(AuPPh3)2(mu2-CO)4(CO)2(PPh3)2 (2). Their M4Au2 cores may be envisioned as substitutional disordered butterfly-based M4Au2 frameworks (M = Pt/Ni) formed by connections of the two basal M(B) atoms with both (Au-Au)-linked Au(PPh3) moieties. Based upon low-temperature CCD X-ray diffraction studies of eight crystals obtained from different samples, ligation-induced site-specific Pt/Ni substitutional disorder (involving formal insertion of Ni in place of Pt) in a given crystal was found to occur only at the one OC-attached basal M(B) site in 1 or at both OC-attached basal M(B) sites in 2 corresponding to a crystal composite of the Pt3(Pt(1-x)Ni(x))Au2 core in 1 or of the Pt2(Pt(2-y)Ni(y))Au2 core in 2; the Ph3P-attached M(B) site (M(B) = Pt) in 1 and two wingtip M(w) sites (M(w) = Pt) in 1 and 2 were not substitutionally disordered. The resulting variable stoichiometry of the M4Au2 core in 1 may be viewed as a crystal composite of two superimposed individual stereoisomers, Pt4(AuPPh3)2(mu2-CO)4(CO)(PPh3)3 (1a) and Pt3Ni(AuPPh3)2(mu2-CO)4(CO)(PPh3)3 (1b), in the averaged unit cell of a given crystal. Likewise, 2 represents the crystal-averaged composite of three individual stereoisomers, Pt4(AuPPh3)2(mu2-CO)4(CO)2(PPh3)2 (2a), Pt3Ni(AuPPh3)2(mu2-CO)4(CO)2(PPh3)2 (2b), and Pt2Ni2(AuPPh3)2(mu2-CO)4(CO)2(PPh3)2 (2c). Formal Ni substitution for Pt at only the basal M(B) site(s) in the four crystal composites each of 1 and 2 was found to vary widely from 17% to 79% Ni in 1 and from 21% to 95% Ni in 2. Nevertheless, reasonably close Pt/Ni occupancy factors were found within each of the four pairs of composite crystals selected from samples obtained from duplicate syntheses. Both 1 and 2 may be formally derived from the electronically equivalent classic butterfly Pt4(mu2-CO)5(PPh3)4 cluster by replacement of its bridging mu2-CO ligand spanning the basal M(B)-M(B) edge with two one-electron donating (Au-Au)-linked AuPPh3 moieties along with the substitution of a terminal CO in place of one or both M(B)-attached PPh3 ligands in 1 and 2, respectively; site-specific Pt/Ni substitutional disorder occurs only at the CO-attached M(B) sites. The variable-stoichiometric 1 and 2 re also electronically equivalent and geometrically related to the crystal-ordered butterfly-based Pt4(mu2-CO)4(PR3)4(mu3-HgX)2 clusters (R3 = Ph3, MePh2; X = CF3, Br, I). PMID:16688317

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

    E-print Network

    MacMillan, Samantha Nicole

    2013-01-01

    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 ...

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

    E-print Network

    Su, Mingjuan

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

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

    PubMed

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

    2013-07-01

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

  6. Stereoelectronic effects in a homologous series of bidentate cyclic phosphines. A clear correlation of hydroformylation catalyst activity with ring size.

    PubMed

    Haddow, Mairi F; Middleton, Ann J; Orpen, A Guy; Pringle, Paul G; Papp, Rainer

    2009-01-01

    The homologous series of diphosphines (CH(2))(n-1)P(CH(2))(3)P(CH(2))(n-1) where n = 5 (L(5)), 6 (L(6)), or 7 (L(7)) have been synthesized from the corresponding PhP(CH(2))(n-1). Treatment of [PtCl(2)(cod)] with L(5-7) gave the 6-membered chelates cis-[PtCl(2)(L(5-7))], the crystal structures for which reveal that L(5-7) have very similar steric bulk and bite angles. Treatment of [Rh(2)Cl(2)(CO)(4)] with L(5-7) gave the binuclear trans-[Rh(2)Cl(2)(CO)(2)(micro-L(5-7))(2)] with syn and anti orientations of the CO and Cl ligands suggested by the (31)P NMR spectra and the crystal structures of syn-trans-[Rh(2)Cl(2)(CO)(2)(micro-L(5))(2)] and anti-trans-[Rh(2)Cl(2)(CO)(2)(micro-L(7))(2)]. The nu(CO) values for trans-[Rh(2)Cl(2)(CO)(2)(micro-L(5-7))(2)] indicate that the donor strength increases in the order L(5) < L(6) < L(7). A study of rhodium-catalysed hydroformylation of 1-octene using diphosphines L(5-7) is described. The catalyst activity decreases with increasing phosphacycle ring size: L(5) > L(6) > L(7). PMID:19081990

  7. Chiral Phosphine-Silver(I) Complex Catalyzed Enantioselective Interrupted Feist-Bénary Reaction with Ynones: The Aldol-Cycloisomerization Cascade.

    PubMed

    Sinha, Debarshi; Biswas, Arnab; Singh, Vinod K

    2015-07-01

    Silver-catalyzed interrupted Feist-Bénary reaction is described for the efficient enantioselective synthesis of dihydrofuran heterocycles. A new method has been developed for the silver(I)-(R)-BINAP complex mediated aldol-cycloisomerization cascade reaction between ynones and 1,3-diketones to provide functionalized dihydrofurans with moderate to good yields (up to 95%) and good to excellent enantiomeric excess (up to 98%). The presence of an exocyclic double bond and hydroxy group in the dihydrofuran products provides wide scope for further structural manipulation. PMID:26106952

  8. Interaction of hydrated protons with octyl-phenyl-N,N-diisobutylcarbamoylmethyl phosphine oxide (CMPO): NMR and theoretical study.

    PubMed

    K?íž, Jaroslav; Dybal, Ji?í; Makrlík, Emanuel; Va?ura, Petr

    2011-10-01

    Interaction of octyl-phenyl-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO, the 'classical' rare metal extraction agent) with fully ionized hydrated protons (HP) was studied in acetonitrile-d(3) using (1)H, (13)C, (31)P NMR, PFG NMR and magnetic relaxation. The experimental results were confronted with high-precision ab initio DFT calculations. Relative chemical shifts of NMR signals of CMPO (0.01 mol/L) under the presence of HP in the molar ratio ? = 0-2.0 mol/mol show binding between CMPO and HP. Self-diffusion measurements using (1)H PFG NMR demonstrate that larger complexes with higher content of CMPO are generally formed at ? < 0.75. Analyzing the collective dependence of (13)C and (31)P NMR chemical shifts on ? by the use of program LETAGROP, we obtained very good fitting for the assumed coexistence of two complexes (CMPO)(2)·HP (C(2)) and CMPO.HP (C(1)). The logarithms of the respective stabilization constants log K(i) were found to be 7.518 (C(2)) and 4.581 (C(1)). The system dynamics was studied by measuring the transverse (1)H NMR relaxation using CPMG sequence with varying delays t(p) between the ? pulses in the mixtures with ? = 0.4-0.8. The following exchange correlation times were obtained: ?(10) = 2.35 × 10(-5), ?(20) = 0.82 × 10(-4), ?(21) = 0.45 × 10(-3) s. The DFT calculations support the conclusion that the complexes C(1) and C(2) are the main species in the mixtures of CMPO with HP. They also agree with the NMR and FTIR observation that the main site to which H(3) O(+) is bound is the P=O group, whereas the amide group does not form a strong bond with the ion when excess water molecules are present. PMID:21898583

  9. Relative Lability and Chemoselective Transmetallation of NHC in Hybrid Phosphine-NHC Ligands: Access to Heterometallic Complexes.

    PubMed

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

    2015-11-01

    The relative lability and transmetallation aptitude of trialkylphosphine and NHC donors, integrated in semi-rigid hybrid ligands attached to [Ag4 Br4 ] pseudo-cubanes, lies in favor of the NHC and is used to selectively access unprecedented NHC complexes with heterobimetallic cores, such as Ag-Cu (4(Cy) ) and Ag-Ir (5(tBu) ). These can be viewed as an arrested state before the full transmetallation of both donors, which gives the homodinuclear Cu (3(Cy) ) and Ir (6(Cy) ) complexes. The observed NHC transmetallation aptitude and reactivity urges caution in the common notion that views the NHC as a universal spectator. PMID:26463419

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

    NASA Astrophysics Data System (ADS)

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

    2009-12-01

    We demonstrate high-efficiency turquoise-blue electrophosphorescence from bis[3,5-bis(2-pyridyl)-1,2,4-triazolato]platinum(II) [Pt(ptp)2] doped in 4-(diphenylphosphoryl)-N ,N-diphenylaniline(HM-A1). Organic light-emitting diodes (OLEDs) with 5% Pt(ptp)2:HM-A1 attain peak power efficiency of 61.2 lm/W, versus 40.8 lm/W for analogous devices employing the standard turquoise-blue phosphor bis[(4,6-difluorophenyl)-pyridinato-N,C2'](picolinato)iridium(III) (FIrpic). Devices with x% Pt(ptp)2:HM-A1 exhibit blue emission maxima (?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.

  11. Extraction of actinides and fission products by octyl(phenyl)-N,N-diisobutylcarbamoylmethyl-phosphine oxide from nitric acid media.

    PubMed

    Mathur, J N; Murali, M S; Natarajan, P R; Badheka, L P; Banerji, A

    1992-05-01

    Extraction of promethium(III), uranium(VI), plutonium(IV), americium(III), zirconium(IV), ruthenium(III), iron(III) and palladium(II) has been carried out with a mixture of octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) and tributyl phosphate (TBP) in dodecane. The effects of nitric acid, TBP and CMPO concentrations on the extraction of these metal ions have been studied. The nature of the species of the above metal ions extracted into the organic phase has been suggested. PMID:18965406

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

    E-print Network

    Khumsubdee, Sakunchai

    2013-11-05

    , 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...

  13. VizieR Online Data Catalog: ExoMol line lists for phosphine (PH3) (Sousa-Silva+,

    NASA Astrophysics Data System (ADS)

    Sousa-Silva, C.; Al-Refaie, A. F.; Tennyson, J.; Yurchenko, S. N.

    2014-11-01

    The data are in two parts. The first, ph3_0-46.dat contains a list of 9,787,832 rovibrational states. Each state is labelled with: 6 normal mode vibrational quantum numbers, 1 multiplexed L quantum number and the vibrational symmetry; three rotational quantum numbers including the total angular momentum J, the projection of J in the z-axis K,rotational symmetry and the total symmetry quantum number Gamma In addition there are nine local mode vibrational numbers and the largest coefficient used to assign the state in question. Each rovibrational state has a unique number, which is the number of the row in which it appears in the file. This number is the means by which the state is related to the second part of the data system, the transitions files. The total degeneracy is also given to facilitate the intensity calculations. Because of their size, the transitions are listed in 100 separate files, each containing all the transitions in a 100cm-1 frequency range. These and their contents are ordered by increasing frequency. The name of the file includes the lowest frequency in the range; thus the a-00500.dat file contains all the transitions in the frequency range 500-600cm-1. The transition files contain three columns: the reference number in the energy file of the upper state; that of the lower state; and the Einstein A coefficient of the transition. The energy file and the transitions files are zipped, and need to be extracted before use. There is a Fortran 90 programme, s_SAlTY.f90 which may be used to generate synthetic spectra (see s_SAlTY.txt for details). Using this, it is possible to generate absorption or emission spectra in either 'stick' form or else cross-sections convoluted with a gaussian with the half-width at half maximum being specified by the user, or with a the temperature-dependent doppler half-width. Sample input files s*.inp for use with sSAlTY.f90 are supplied. (10 data files).

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

    E-print Network

    Wu, Xiaoxing

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

  15. Reactivity of Phosphanylphosphinidene Complex of Tungsten(VI) toward Phosphines: A New Method of Synthesis of catena-Polyphosphorus Ligands.

    PubMed

    Grubba, Rafa?; Ordyszewska, Anna; Kaniewska, Kinga; Ponikiewski, ?ukasz; Chojnacki, Jaros?aw; Gudat, Dietrich; Pikies, Jerzy

    2015-09-01

    The reactivity of an anionic phosphanylphosphinidene complex of tungsten(VI), [(2,6-i-Pr2C6H3N)2(Cl)W(?(2)-t-Bu2P?P)]Li·3DME toward PMe3, halogenophosphines, and iodine was investigated. Reaction of the starting complex with Me3P led to formation of a new neutral phosphanylphosphinidene complex, [(2,6-i-Pr2C6H3N)2(Me3P)W(?(2)-t-Bu2P?P)]. Reactions with halogenophosphines yielded new catena-phosphorus complexes. From reaction with Ph2PCl and Ph2PBr, a complex with an anionic triphosphorus ligand t-Bu2P-P((-))-PPh2 was isolated. The main product of reaction with PhPCl2 was a tungsten(VI) complex with a pentaphosphorus ligand, t-Bu2P-P((-))-P(Ph)-P((-))-P-t-Bu2. Iodine reacted with the starting complex as an electrophile under splitting of the P-P bond in the t-Bu2P?P unit to yield [(1,2-?-t-Bu2P-P-P-t-Bu2)W(2,6-i-Pr2C6H3N)2Cl], t-Bu2PI, and phosphorus polymers. The molecular structures of the isolated products in the solid state and in solution were established by single crystal X-ray diffraction and NMR spectroscopy. PMID:26287312

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

    SciTech Connect

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

    2014-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1987-01-01

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

  18. Steric and Electronic Effects on the Insertion of a Rhodium Phosphine Complex into the C-S Bond of

    E-print Network

    Jones, William D.

    ,6-Dimethyldibenzothiophene formed a labile S-bound complex which was observed to lose thiophene by substitution with free, and a decrease in air pollution from acid rain could be achieved through these investigations.2 Thiophene

  19. Ruthenium(II) complexes containing N(4)-tolyl-2-acetylpyridine thiosemicarbazones and phosphine ligands: NMR and electrochemical studies of cis- trans isomerization

    NASA Astrophysics Data System (ADS)

    Graminha, Angelica E.; Batista, Alzir A.; Ellena, Javier; Castellano, Eduardo E.; Teixeira, Letícia R.; Mendes, Isolda C.; Beraldo, Heloisa

    2008-03-01

    [Ru(HL)(PPh 3) 2Cl]Cl complexes have been obtained in which HL = N(4)- ortho (complex 1), N(4)- meta (complex 2) and N(4)- para-tolyl 2-acetylpyridine thiosemicarbazone (complex 3). NMR and electrochemical studies indicate that both cis and trans isomers exist in solution, and that the cis isomers are converted into the trans isomers with time. Crystal structure determination of ( 1) reveals that the trans isomer is formed in the solid state.

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

    SciTech Connect

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

    2009-07-20

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

  1. Brilliant photoluminescence and triboluminescence from ternary complexes of Dy(III) and Tb(III) with 3-phenyl-4-propanoyl-5-isoxazolonate and a bidentate phosphine oxide coligand.

    PubMed

    Biju, S; Gopakumar, N; Bünzli, J-C G; Scopelliti, R; Kim, H K; Reddy, M L P

    2013-08-01

    Three new lanthanide heterocyclic ?-diketonate complexes [Dy(PPI)3(EtOH)2] (1), [Dy(PPI)3(DPEPO)] (2), and [Tb(PPI)3(DPEPO)] (3) [where HPPI = 3-phenyl-4-propanoyl-5-isoxazolone and DPEPO = bis(2-(diphenylphosphino)phenyl)ether oxide] have been synthesized and fully characterized. Single-crystal X-ray diffraction analyses reveal that these complexes are mononuclear and that the central Ln(III) ion is coordinated to eight oxygen atoms that are provided by three bidentate ?-diketonate ligands and ethanol or bidentate DPEPO in a distorted square antiprismatic geometry. These complexes have high molar absorption coefficients (up to 3 × 10(4) M(-1) cm(-1) at 285 nm) and display strong visible and, for Dy(III), NIR luminescence upon irradiation at the ligand-centered band in the range 250-350 nm. The emission quantum yields and the luminescence lifetimes at room temperature are 3 ± 0.5% and 15 ± 1 ?s for 1, 12 ± 2% and 33 ± 1 ?s for 2, and 42 ± 6% and 795 ± 1 ?s for 3. Moreover, the crystals of 2 and 3 exhibit brilliant triboluminescence, visible in daylight. PMID:23848056

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

    SciTech Connect

    Tu, J.I.; Brennan, J.; Stouffer, B.; Eckelman, W.C. )

    1990-07-01

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

  3. Chiral phosphine-catalyzed asymmetric transformations of allenoates and alkynoates and photoinduced, copper-catalyzed C-N couplings with aromatic nitrogen ceterocycles

    E-print Network

    Ziegler, Daniel Todd

    2015-01-01

    Chapter 1 describes the development of chiral biphenyl-derived phosphepines and their application as catalysts for an asymmetric [4 + 1] annulation to form functionalized cyclopentenes bearing a non-spirocyclic quaternary ...

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

    PubMed

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

    2015-10-01

    A new host material based on the 2,7,4'-substituted spirobifluorene platform has been designed and used in single-layer phosphorescent OLED with very high efficiency (EQE = 13.2%) and low turn-on voltage (2.4 V). This performance is among the best reported for green single-layer PhOLEDs and may open new avenues in the design of host materials for single-layer devices. PMID:26371550

  5. New alkyl derivatives phosphine sulfonate (P-O) ligands. Catalytic activity in Pd-catalysed Suzuki-Miyaura reactions in water.

    PubMed

    García Suárez, Eduardo J; Ruiz, Aurora; Castillón, Sergio; Oberhauser, Werner; Bianchini, Claudio; Claver, Carmen

    2007-07-21

    Two novel bis(o-methoxyphenyl) phosphinoalkylsulfonate (P-O) ligands have been prepared through a new and sustainable synthetic route; they are air stable as well as water soluble and have been applied in Pd-catalysed Suzuki-Miyaura cross-coupling reactions in neat water in conjunction with microwave heating. PMID:17607399

  6. 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)

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

    2014-10-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

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

    NASA Astrophysics Data System (ADS)

    Ji, Jeong-Young

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

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

    E-print Network

    Guenther, Johannes 1983-

    2012-08-16

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

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

    PubMed

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

    2015-04-17

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

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

    SciTech Connect

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

    2009-07-20

    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.

  12. Quantum chemical characterization and design of host materials based on phosphine oxide-substituted (triphenylamine) fluorene for (deep) blue phosphors in OLEDs.

    PubMed

    Wu, Jie; Wu, Shui-Xing; Wu, Yong; Kan, Yu-He; Geng, Yun; Su, Zhong-Min

    2013-02-21

    We studied the electronic structures of a series of fluorene derivatives (p/mPODPFs and p/mPOAPFs) using density functional theory calculations and investigated their performances as host materials in organic light-emitting diodes from three aspects, i.e. triplet energy, ability of charge injection from neighboring organic layer or electrode, and match of the hosts and the reference guests (FIrpic and FCNIr) for efficient energy transfer (EF). Especially for the last aspect, the singlet/triplet (S(1)/T(1)) energies as well as the simulated host emission and guest absorption spectra are investigated to predict the possible emission mechanisms in the host-guest system and therefore to pursue the most suitable host for (deep) blue guest. From the investigated results, we deduced that pPODPF and pPOAPF are suitable for sky-blue FIrpic due to feasible Förster/Dexter energy transfers from pPODPF/pPOAPF to FIrpic, which agrees well with the experimental results. Furthermore, the higher external quantum efficiency (20.6%) of the pPOAPF-based device than that of the pPODPF-based device (13.2%) in experiments was inferred to be attributed to the matching S(1) energies between pPOAPF and FIrpic as well as good hole/electron injection abilities of pPOAPF in spite of a smaller overlap between the pPOAPF emission and FIrpic absorption spectra. By contrast, mPOAPF and mPODPF, designed in the work, may match with deep-blue FCNIr. In particular, mPOAPF may exhibit good performance as a host material for deep blue FCNIr as a consequence of its own balanced hole/electron injection ability and the matching S(1)/T(1) energies between mPOAPF and FCNIr. PMID:23295787

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

    SciTech Connect

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

    1988-08-01

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

  14. The [MoFe3S4]2+ oxidation state: synthesis, substitution reactions, and structures of phosphine-ligated cubane-type clusters with the S=2 ground state.

    PubMed

    Xi, Bin; Holm, R H

    2011-07-01

    The cluster [(Tp)MoFe(3)S(4)(PEt(3))(3)](1+) containing the cubane-type [MoFe(3)(?(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)MoFe(3)S(4)(PEt(3))(3-n)L(n)](1-n) with L = halide, N(3)(-), PhS(-), PhSe(-), R(3)SiO(-), and R(3)SiS(-) 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 Mo?ssbauer spectra consist of two doublets in a 2:1 intensity ratio. (57)Fe isomer shifts are consistent with the mean oxidation state Fe(3)(2.33+) arising from electron delocalization of the mixed-valence oxidation state description [Mo(3+)Fe(3+)Fe(2+)(2)]. Reaction of [(Tp)MoFe(3)S(4)(PEt(3))(2)Cl] with (Me(3)Si)(2)S affords [(Tp)MoFe(3)S(4)(PEt(3))(2)(SSiMe(3))], a likely first intermediate in the formation of the tricluster compound {[(Tp)MoFe(3)S(4)(PEt)(2)](3)S}(BPh(4)) from the reaction of [(Tp)MoFe(3)S(4)(PEt(3))(3)](BPh(4)) and NaSSiMe(3) in tetrahydrofuran (THF). The tricluster consists of three cluster units bound to a central ?(3)-S atom in a species of overall C(3) symmetry. Relatively few clusters in the [MoFe(3)S(4)](2+) oxidation state have been prepared compared to the abundance of clusters in the oxidized [MoFe(3)S(4)](3+) state. This work is the first comprehensive study of the [MoFe(3)S(4)](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

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

    E-print Network

    Surawatanawong, Panida

    2010-07-14

    The electronic structures and reaction mechanisms of transition-metal complexes can be calculated accurately by density functional theory (DFT) in cooperation with the continuum solvation model. The palladium catalyzed ...

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

    PubMed

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

    2015-01-21

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

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

    PubMed

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

    2015-06-15

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

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

    E-print Network

    Arizpe, Luis (Luis Alfredo)

    2011-01-01

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

  19. Studies of Soluble Polymer-supported Organocatalysts 

    E-print Network

    Yang, Yun-Chin

    2012-10-19

    in addition and allylic amination reactions. The PIB-bound phosphines were useful reagents in aza-Wittig and Mitsunobu reactions. The PIB-bound phosphine oxides formed either from adventitious oxidation or during the course of reactions can be reduce to PIB...

  20. Hydroformylation: An Old Yet New Industrial Route to Alcohols.

    ERIC Educational Resources Information Center

    Pruett, Roy L.

    1986-01-01

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

  1. Nickel precatalysts as enabling tools for catalytic coupling reactions

    E-print Network

    Standley, Eric A. (Eric Alan)

    2015-01-01

    [Chemical formula] A series of air-stable nickel complexes of the form L?Ni(aryl)X (L = monodentate phosphine, X = Cl, Br) and LNi(aryl)X (L = bis-phosphine) have been synthesized and are presented as a library of precatalysts ...

  2. D.M.P. MINGOS Publications

    E-print Network

    Wallace, Mark

    , 1968, 419. 2 D.M.P. Mingos, J. Chatt, G.J. Leigh and R.J. Paske; "Complexes of Osmium, Ruthenium, Osmium, Rhodium, Iridium and Platinum Halides with Mono(tertiary phosphines) and Mono(tertiary arsines of Ruthenium, Osmium, Iridium and Platinum Halides with Tertiary Phosphines and Arsines", Journal

  3. The Palladium Component of an Immobilized Sonogashira Catalyst System: New Insights by Multinuclear HRMAS NMR Spectroscopy

    E-print Network

    Bluemel, Janet

    The Palladium Component of an Immobilized Sonogashira Catalyst System: New Insights by Multinuclear: Multinuclear one- and two-dimensional HRMAS NMR spectroscopy has been used to investigate the palladium of palladium bis(phosphine) complexes are possible,8 the steric demand of the phosphine substituents favors

  4. Published: August 03, 2011 r 2011 American Chemical Society 13337 dx.doi.org/10.1021/ja200231v |J. Am. Chem. Soc. 2011, 133, 1333713348

    E-print Network

    Goddard III, William A.

    In particular, activated allenes subjected to nucleophilic phosphine catalysis conditions exhibit superbly materials. Among the catalytic systems, nucleophilic phosphine catalysis has been established as a reliable-, or four-carbon synthons when reacting with a variety of electrophilic coupling partners (including

  5. Conjugate and method for forming aminomethyl phosphorus conjugates

    DOEpatents

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

    1999-01-01

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

  6. A Broadly Applicable Strategy for Entry into Homogeneous Nickel(0) Catalysts from Air-Stable Nickel(II) Complexes

    E-print Network

    Smith, Stacey J.

    A series of air-stable nickel complexes of the form L[subscript 2]Ni(aryl) X (L = monodentate phosphine, X = Cl, Br) and LNi(aryl)X (L = bis-phosphine) have been synthesized and are presented as a library of precatalysts ...

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

    PubMed

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

    2015-04-15

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

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

    DOEpatents

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

    2011-12-06

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

  9. Methods for removing contaminant matter from a porous material

    DOEpatents

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

    2010-11-16

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

  10. Polyphosphazine-based polymer materials

    DOEpatents

    Fox, Robert V.; Avci, Recep; Groenewold, Gary S.

    2010-05-25

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

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

    NASA Technical Reports Server (NTRS)

    Buckley, D. H.

    1973-01-01

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

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

    PubMed

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

    2015-05-18

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

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

    PubMed

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

    2015-01-01

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

  14. The adsorption and subsequent oxidation of AsH 3 and PH 3 on activated carbon

    NASA Astrophysics Data System (ADS)

    Colabella, J. M.; Stall, R. A.; Sorenson, C. T.

    1988-10-01

    In the following discussion, we will show that arsine and phosphine, which have been adsorbed onto activated carbon, can be oxidized to form arsenic trioxide and various phosphorus compounds related to PO 4. By controlling the rate of oxidation, the rate of heat generation can also be controlled. The maximum temperature achieved in the scrubber was 189°C during arsine oxidation and 198°C for phosphine oxidation at linear flow velocities of 0.35 and 0.46 ft/min, respectively. The oxygen to hydride ratio used ranged from 3.5-6.3: 1 and 5.1-8.6: 1 for arsine and phosphine oxidation, respectively.

  15. Synthesis of the elusive (R3P)2MF2 (M = Pd, Pt) complexes.

    PubMed

    Yahav, Anette; Goldberg, Israel; Vigalok, Arkadi

    2003-11-12

    The synthesis and characterization of previously unknown palladium(II) and platinum(II) difluoro phosphine complexes are described. These complexes can be obtained either via a halide metathesis reaction with AgF in dichloromethane or by reacting the corresponding dimethyl complexes with XeF2. While the Pt(II) complexes can be prepared with both aryl- and alkyl-phosphine ligands, the stability of the Pd(II) complexes is limited to those having cis-oriented trialkyl phosphine ligands. PMID:14599181

  16. Nickel-Catalyzed Allylic Substitution of Simple Alkenes

    E-print Network

    Matsubara, Ryosuke

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

  17. Functionalization of Cp4Fe4(CO)4: Contrasts and Comparisons with Mark D. Westmeyer, Mark A. Massa, Thomas B. Rauchfuss,* and Scott R. Wilson

    E-print Network

    Rauchfuss, Thomas B.

    bonding sites, in surface binding (i.e. catalyst anchoring), and in molecular recognition.1 The use functionalities such as vinyl, silylene, and persulfido.9,10 Electroactive phosphine-function- alized metallocenes

  18. Rhodium-Catalyzed Asymmetric Intramolecular Hydroamination of Unactivated Alkenes

    E-print Network

    Shen, Xiaoqiang

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

  19. Chemoselective ligation

    DOEpatents

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

    2011-04-12

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

  20. Chemoselective ligation

    DOEpatents

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

    2011-05-10

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

  1. Chemoselective ligation

    DOEpatents

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

    2011-12-13

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

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

    E-print Network

    Fujiwara, Yuji

    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 ...

  3. Highly active supported palladium catalyst for the regioselective synthesis of 2-arylpropionic acids by carbonylation

    E-print Network

    Jayasree, S.; Seayad, A.; Chaudhari, Raghunath Vitthal

    1999-01-01

    A catalyst system consisting of supported palladium in the presence of phosphine ligands, TsOH and LiCl catalyses the carbonylation of 1-arylethanols to 2-arylpropionic acids with significantly improved activity and ...

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

    E-print Network

    Shen, Xiaoqiang

    2010-01-01

    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 ...

  5. Design and preparation of new palladium precatalysts for C–C and C–N cross-coupling reactions

    E-print Network

    Bruno, Nicholas C.

    A series of easily prepared, phosphine-ligated palladium precatalysts based on the 2-aminobiphenyl scaffold have been prepared. The role of the precatalyst-associated labile halide (or pseudohalide) in the formation and ...

  6. Homochiral metal complexes for biodegradable polymer synthesis 

    E-print Network

    Buffet, Jean-Charles

    2010-01-01

    Chapter One introduces the principle of alkoxide and phosphine oxide as ligands for lanthanides and electropositive metals, ligand self-recognition, stereoselective polymerisation of lactide, fixation of CO2 and finally ...

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

    E-print Network

    Zhu, Ye

    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 ...

  8. Smallpox Disease Overview

    MedlinePLUS

    ... Methyl bromide Methyl isocyanate Nicotine Nitrogen mustard Opioids Organic solvents Osmium tetroxide Paraquat Phosgene Phosgene oxime Phosphine ... Doing What You Can Do Blog: Public Health Matters What's New A - Z Index SMALLPOX FACT SHEET ...

  9. Vaccine Reaction Images

    MedlinePLUS

    ... Methyl bromide Methyl isocyanate Nicotine Nitrogen mustard Opioids Organic solvents Osmium tetroxide Paraquat Phosgene Phosgene oxime Phosphine ... Doing What You Can Do Blog: Public Health Matters What's New A - Z Index Vaccine Reaction Images* ...

  10. Smallpox Disease Images

    MedlinePLUS

    ... Methyl bromide Methyl isocyanate Nicotine Nitrogen mustard Opioids Organic solvents Osmium tetroxide Paraquat Phosgene Phosgene oxime Phosphine ... Doing What You Can Do Blog: Public Health Matters What's New A - Z Index Smallpox Disease Images* ...

  11. Facts about Botulism

    MedlinePLUS

    ... Methyl bromide Methyl isocyanate Nicotine Nitrogen mustard Opioids Organic solvents Osmium tetroxide Paraquat Phosgene Phosgene oxime Phosphine ... Doing What You Can Do Blog: Public Health Matters What's New A - Z Index Facts about Botulism ...

  12. Chemoselective ligation

    DOEpatents

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

    2010-11-23

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

  13. Chemoselective ligation

    DOEpatents

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

    2010-02-23

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

  14. Biochemml Pharmocolog,v, Vol.40.No.12.pp.2587-2596. 1990. PrintedinGreatBritain.

    E-print Network

    Hammock, Bruce D.

    as phenyl valerate hydrolysis which is resistant to treatment with paraoxon and sensitive to co, phosphinates, carbamates, and sul- fates were examined. Analysis of the results involved the examination

  15. Novel palladium precatalysts and their application in cross- coupling reactions and copper-catalyzed enantioselective ring formation

    E-print Network

    Bruno, Nicholas C. (Nicholas Charles)

    2015-01-01

    Chapters 1 - 3. A series of easily prepared, phosphine-ligated palladium precatalysts based on the 2-aminobiphenyl scaffold have been prepared. The role of the precatalyst-associated labile halide (or pseudohalide) in the ...

  16. Elastomer-modified phosphorus-containing imide resins

    NASA Technical Reports Server (NTRS)

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

    1983-01-01

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

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

    ERIC Educational Resources Information Center

    Cerrada, Elena; Laguna, Mariano

    2005-01-01

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

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

    E-print Network

    Spokoyny, Alexander M.

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

  19. Chemoselective ligation

    DOEpatents

    Saxon, Eliana; Bertozzi, Carolyn

    2006-10-17

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

  20. Chemoselective ligation

    DOEpatents

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

    2003-05-27

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

  1. Minimizing Aryloxy Elimination in Rh(I) -Catalyzed Asymmetric Hydrogenation of ?-Aryloxyacrylic Acids using a Mixed-Ligand Strategy.

    PubMed

    Li, Yang; Wang, Zheng; Ding, Kuiling

    2015-11-01

    The first example of efficient asymmetric hydrogenation of challenging ?-aryloxyacrylic acids was realized using a Rh(I) -complex based on the heterocombination of a readily available chiral monodentate secondary phosphine oxide (SPO) and an achiral monodentate phosphine ligand as the catalyst. Excellent enantioselectivities (92->99?% ee) were achieved for a wide variety of chiral ?-aryloxypropionic acids with minor aryloxy elimination in most cases. The resultant products were readily transformed into biologically active compounds through simple synthetic manipulations. PMID:26424205

  2. Methods for suppressing isomerization of olefin metathesis products

    SciTech Connect

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

    2015-09-22

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

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

    E-print Network

    Bugarin Cervantes, Alejandro

    2011-08-08

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

  4. Ortho-phosphinobenzenesulfonate: a superb ligand for palladium-catalyzed coordination-insertion copolymerization of polar vinyl monomers.

    PubMed

    Nakamura, Akifumi; Anselment, Timo M J; Claverie, Jerome; Goodall, Brian; Jordan, Richard F; Mecking, Stefan; Rieger, Bernhard; Sen, Ayusman; van Leeuwen, Piet W N M; Nozaki, Kyoko

    2013-07-16

    Ligands, Lewis bases that coordinate to the metal center in a complex, can completely change the catalytic behavior of the metal center. In this Account, we summarize new reactions enabled by a single class of ligands, phosphine-sulfonates (ortho-phosphinobenzenesulfonates). Using their palladium complexes, we have developed four unusual reactions, and three of these have produced novel types of polymers. In one case, we have produced linear high-molecular weight polyethylene, a type of polymer that group 10 metal catalysts do not typically produce. Secondly, complexes using these ligands catalyzed the formation of linear poly(ethylene-co-polar vinyl monomers). Before the use of phosphine-sulfonate catalysts, researchers could only produce ethylene/polar monomer copolymers that have different branched structures rather than linear ones, depending on whether the polymers were produced by a radical polymerization or a group 10 metal catalyzed coordination polymerization. Thirdly, these phosphine-sulfonate catalysts produced nonalternating linear poly(ethylene-co-carbon monoxide). Radical polymerization gives ethylene-rich branched ethylene/CO copolymers copolymers. Prior to the use of phosphine-sulfonates, all of the metal catalyzed processes gave completely alternating ethylene/carbon monoxide copolymers. Finally, we produced poly(polar vinyl monomer-alt-carbon monoxide), a copolymerization of common polar monomers with carbon monoxide that had not been previously reported. Although researchers have often used symmetrical bidentate ligands such as diimines for the polymerization catalysis, phosphine-sulfonates are unsymmetrical, containing two nonequivalent donor units, a neutral phosphine, and an anionic sulfonate. We discuss the features that make this ligand unique. In order to understand all of the new reactions facilitated by this special ligand, we discuss both the steric effect of the bulky phosphines and electronic effects. We provide a unified interpretation of the unique reactivity by considering of the net charge and the enhanced back donation in the phosphine-sulfonate complexes. PMID:23544427

  5. Croissance épitaxique de GaAs1- xPx (0 < x < 0.6) par OM-CVD á partir du complexe CIEt 2Ga·AsEt 3 et de la diethyl phosphine: une source de phosphore originale HPEt 2

    NASA Astrophysics Data System (ADS)

    Maury, F.; Constant, G.

    1983-08-01

    Growth of GaAs1- xPx epitaxial layers (0 < x < 0.6) on GaAs, and Ge substrates has been realized by OM-CVD with CIEt 2Ga·AsEt 3 and HPEt 2 used as element source for Ga, As and P in the temperature range of 500-650°C. The growth rate strongly depends on the deposition temperature and reaches a maximum at 600°C. The P content of the alloys increases with the HPEt 2 molar fraction in the vapor phase but is quite independent of the substrate temperature in the range of 500-600°C. The study of the influence of the parameters shows that the growth mechanism differs from the one which occurs when AsH 3 and PH 3 are used. The good reactivity of HPEt 2 is discussed and led us to propose this molecule as the phosphorus source in OM-CVD.

  6. New adamantane-like mercury-chalcogen cages. Synthetic and multinuclear (/sup 31/P, /sup 77/Se, /sup 199/Hg) NMR study of ((. mu. -ER)/sub 6/(HgL)/sub 4/)/sup 2 +/ (E = S or Se; L = tertiary phosphine or arsine) and related species with mixed ligands

    SciTech Connect

    Dean, P.A.W.; Vittal, J.J.; Trattner, M.H.

    1987-12-16

    Reaction between HgL/sub 2/(ClO/sub 4/)/sub 2/, Hg(ER)/sub 2/, and L in a 1:3:2 ratio produces the isolable salts ((..mu..-ER)/sub 6/(HgL)/sub 4/)(ClO/sub 4/)/sub 2/ (L = PPh/sub 3/, ER = SePh, SPh, SMe, or SEt; L = AsPh/sub 3/, ER = SPh; L = PEt/sub 3/, ER = SePh or SPh). Multinuclear (/sup 31/P, /sup 77/Se, /sup 199/Hg) NMR was used to demonstrate the adamantanoid structure of the cations in these salts as well as in those with L = PPh/sub 3/ and ER = S-n-Pr, S-n-Bu, or S-n-C/sub 5/H/sub 11/, which were studied in situ. To confirm that the new cations contain the hitherto unobserved (..mu..-ER)/sub 6/Hg/sub 4/ core, several series of clusters with mixed ligands were investigated (as ClO/sub 4//sup -/ salts) by the multinuclear NMR technique also. The systems ((..mu..-ER)/sub 6/(HgL)/sub 4/)/sup 2 +/-((..mu..-ER)/sub 6/(HgL')/sub 4/)/sup 2 +/ (ER = SePh, L = PPh/sub 3/, L' = PEt/sub 3/; ER = SPh, L = PPh/sub 3/, L' = PEt/sub 3/ or AsPh/sub 3/) give the series ((..mu..-ER)/sub 6/(HgL)/sub 4-n/(HgL')/sub n/)/sup 2 +/ (n = 0-4). The related species ((..mu..-SPh)/sub 6/(HgPPh/sub 3/)/sub 4-n/(HgSbPh/sub 3/)/sub n/)/sup 2 +/ (n = 0-2 and possibly 3) were produced from Hg(PPhh/sub 3/)/sub 2/(ClO/sub 4/)/sub 2/, Hg(SPh)/sub 2/, and SbPh/sub 3/. From the notably rich /sup 31/P and /sup 199/Hg NMR spectra of the system ((..mu..-SPh)/sub 6/(HgPPh/sub 3/)/sub 4/)/sup 2 +/-((..mu..-SePh)/sub 6/(HgPPh/sub 3/)/sub 4/)/sup 2 +/ it was possible to demonstrate the existence of every possible mixed-chalcogen core in the series ((..mu..-SPh)/sub 6-m/(..mu..-SePh)/sub m/(HgPPh/sub 3/)/sub 4/)/sup 2 +/ (m = 0-6). The new (..mu..-SR)/sub 6/Hg/sub 4/ cages are possible models for the proposed Hg/sub 4/(Cys)/sub 11/ cluster in Hg/sub 7/-metallothionein. 46 references, 3 figures, 2 tables.

  7. Synthesis and structural analysis of the first nanosized platinum-gold carbonyl/phosphine cluster, Pt13[Au2(PPh3)2]2(CO)10(PPh3)4, containing a Pt-centered [Ph3PAu-AuPPh3]-capped icosahedral Pt12 cage.

    PubMed

    de Silva, Namal; Dahl, Lawrence F

    2005-12-26

    The preparation and molecular structure of the initial nanosized platinum-gold carbonyl cluster, Pt(13)[Au(2)(PPh(3))(2)](2)(CO)(10)(PPh(3))(4) (1), are described. A comparative analysis reveals its pseudo-D(2)(h) geometry, consisting of a centered Pt(13) icosahedron encapsulated by two centrosymmetrically related bidentate [Ph(3)PAu-AuPPh(3)]-capped ligands along with 4 PR(3) and 10 CO ligands, to be remarkably similar to that of the previously reported Pt(17)(mu(2)-CO)(4)(CO)(8)(PEt(3))(8) (2). Reformulation of 2 as Pt(13)[(PtPEt(3))(2)(mu(2)-CO)](2)(CO)(10)(PEt(3))(4) emphasizes the steric/electronic resemblance of the bulky-sized bidentate [Ph(3)PAu-AuPPh(3)] and [(PtPEt(3))(2)(mu(2)-CO)] capping ligands in 1 and 2, respectively, as well as their identical electron counts of 162 cluster valence electrons for a centered Pt(13) icosahedron. We hypothesize that analogous steric effects of their ligand polyhedra in 1 and 2 play a crucial role along with electronic effects in the formation and stabilization of these two nanosized clusters that contain an otherwise unknown centered icosahedron of platinum atoms. PMID:16363819

  8. Synthesis of low color, atomic oxygen resistant polyimides

    NASA Technical Reports Server (NTRS)

    MacInnes, Dave

    1995-01-01

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

  9. Biological formation of volatile phosphorus compounds.

    PubMed

    Roels, J; Verstraete, W

    2001-09-01

    Phosphine and phosphides are reported to occur at numerous environmental sites such as fresh and marine sediments, landfills, faecal matter, biogas digesters and soils. The concentrations are several log units lower than the time-weighted average exposure standard, i.e. in the order of ng per m3 of gas or ng per kg material. Research about the biological formation of highly reduced gaseous phosphorus compounds dates back more than a hundred years. The early reports had to deal with a lot of scepticism. Thanks to new analytical tools (gas chromatography) it has become clear, during the last decade, that phosphine is a global constituent of the atmosphere. Pure strains of micro-organisms cultivated under highly anaerobic conditions were shown to produce phosphine. Thermodynamic considerations indicate that it is very improbable that the reduction of phosphate to phosphine is endergonic. Therefore the generation of phosphine cannot be compared with sulphidogenesis and methanogenesis. There seems to be a link between the existence of highly reactive gaseous phosphorus compounds and increased levels of metal corrosion. The reactive compounds could be formed by micro-organisms or they are liberated from phosphorus-containing impurities in the iron by the action of bacterial metabolites. The biochemical pathways responsible for the production of gaseous phosphorus compounds have not been characterised yet. PMID:11499578

  10. High Efficiency InP Solar Cells from Low Toxicity Tertiarybutylphosphine

    NASA Technical Reports Server (NTRS)

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

    1994-01-01

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

  11. Evolution of hydroformylation chemistry

    SciTech Connect

    Slaugh, L.H.

    1995-12-01

    A new generation of hydroformylation catalysts was discovered in 1960 at Shell Development Company which dramatically altered the chemistry of producing industrially important alcohols from synthesis gas (CO/H{sub 2}) and olefins. These new homogeneous catalysts were obtained via the use of auxiliary tertiary phosphine ligands with the conventional OXO cobalt carbonyl catalyst. This is believed to have been the first historical example illustrating the utility of phosphine ligands to modify the catalytic properties of homogenous catalysts. In contradistinction to the conventional OXO reaction, highly linear alcohols were obtained in a single-step operation with ease of catalyst recycle. Based on this discovery, an industrial process was developed to produce large volume, environmentally friendly detergent alcohols. The chemistry of this process and a comparison with other hydroformylation catalyst systems will be made. Recent results obtained with phosphine-modified cobalt catalysts for the hydroformylation of substrates other than olefins will be presented.

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

    SciTech Connect

    Youngman, P.W.; Fitch, J.W.; Cassidy, P.E.

    1996-10-01

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

  13. A Strategy to Control the Reactivation of Frustrated Lewis Pairs from Shelf-Stable Carbene Borane Complexes

    PubMed Central

    Hoshimoto, Yoichi; Kinoshita, Takuya; Ohashi, Masato; Ogoshi, Sensuke

    2015-01-01

    N-Phosphine oxide substituted imidazolylidenes (PoxIms) have been synthesized and fully characterized. These species can undergo significant changes to the spatial environment surrounding their carbene center through rotation of the phosphine oxide moiety. Either classical Lewis adducts (CLAs) or frustrated Lewis pairs (FLPs) are thus formed with B(C6F5)3 depending on the orientation of the phosphine oxide group. A strategy to reactivate FLPs from CLAs by exploiting molecular motions that are responsive to external stimuli has therefore been developed. The reactivation conditions were successfully controlled by tuning the strain in the PoxIm–B(C6F5)3 complexes so that reactivation only occurred above ambient temperature. PMID:26315680

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

    DOEpatents

    Ramprasad, D.; Waller, F.J.

    1999-04-06

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

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

    DOEpatents

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

    1999-01-01

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

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

    DOEpatents

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

    2001-01-01

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

  17. Phosphorus-containing imide resins

    NASA Technical Reports Server (NTRS)

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

    1983-01-01

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

  18. Phosphorus-containing imide resins

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

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

  19. Zinc Phosphide Poisoning

    PubMed Central

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

    2014-01-01

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

  20. Partial pressures and nature of products. Application to the photolysis of PH 3 and NH 3 in the atmosphere of jupiter and saturn

    NASA Astrophysics Data System (ADS)

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

    The photolysis of mixtures of gases containing NH 3 or PH 3 presents important differences mainly due to the strength of the X-H bond. On some examples, these differences are evidenced and the consequences for mixtures of gases containing these two compounds are shown: the photolysis of ammonia and ethylene mainly gives ethyl-, butyl- and hexylamine whereas the photolysis of phosphine and ethylene leads to ethyl- and vinylphosphine. When gaseous mixtures of NH 3, PH 3 and ethylene are photolyzed together, the presence of phosphine dramatically decreases the formation of nitrogen derivatives. The relevance of such lab studies to the atmospheres of Jupiter and Saturn is discussed.

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

    PubMed Central

    2014-01-01

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

  2. Exploring new generations of ruthenium olefin metathesis catalysts: the reactivity of a bis-ylidene ruthenium complex by DFT.

    PubMed

    Poater, Albert; Credendino, Raffaele; Slugovc, Christian; Cavallo, Luigi

    2013-05-28

    Density functional theory calculations were used to predict the behaviour of a potential novel architecture of olefin metathesis catalysts, in which one of the neutral ligands of classical Ru-based catalysts, e.g. a phosphine or an N-heterocyclic carbene, is replaced by an alkylidene group. Introduction of a second alkylidene ligand favors dissociation of the remaining phosphine and the overall energy profile for the metathesis using ethylene as the probe substrate reveals that the proposed bis-alkylidene complexes might match the requirements of a good performing olefin metathesis catalyst. PMID:23426093

  3. Investigations on low-temperature MOVPE growth of InGaAs/InP using alternative sources (TBAs, TBP)

    SciTech Connect

    Czub, M.; Strupinski, W.; Weber, J.; Gyuro, I.

    1996-12-31

    Growth of high quality InP and InGaAs using the less hazardous liquid group V precursors, TBAs and TBP has been achieved. A systematic study compares the quality of InP and InGaAs epitaxial layers grown by low-pressure organometallic vapor phase epitaxy (MOVPE) using TMG and TEG trimethylindium (TMIn), phosphine (PH{sub 3}), arsino (AsH{sub 3}) and tetriarybutylophosphine (TBP) and tertriarybutylarsin (TBAs) sources. High quality InP Layers are obtained with both phosphorus sources for growth at high V/III ratio and at low temperatures with the TBP, TBAs sources than with the phosphine and arsine sources.

  4. Aluminium phosphide-induced leukopenia

    PubMed Central

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

    2013-01-01

    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

  5. Crystallographic analysis of transition-state mimics bound to penicillopepsin: phosphorus-containing peptide analogues.

    PubMed

    Fraser, M E; Strynadka, N C; Bartlett, P A; Hanson, J E; James, M N

    1992-06-01

    The molecular structures of three phosphorus-based peptide inhibitors of aspartyl proteinases complexed with penicillopepsin [1, Iva-L-Val-L-Val-StaPOEt [Iva = isovaleryl, StaP = the phosphinic acid analogue of statine [(S)-4-amino-(S)-3-hydroxy-6-methylheptanoic acid] (IvaVVStaPOEt)]; 2, Iva-L-Val-L-Val-L-LeuP-(O)Phe-OMe [LeuP = the phosphinic acid analogue of L-leucine; (O)Phe = L-3-phenyllactic acid; OMe = methyl ester] [Iva VVLP(O)FOMe]; and 3, Cbz-L-Ala-L-Ala-L-LeuP-(O)-Phe-OMe (Cbz = benzyloxycarbonyl) [CbzAALP(O)FOMe

  6. Alternative fumigants to methyl bromide for killing pupae and preventing emergence of apple maggot fly (Diptera:Tephritidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Effects of methyl bromide, ECO2FUME (phosphine gas + CO2), Vapam (sodium methyldithiocarbamate), chloropicrin, Telone II (1, 3 dichloropropene), and chloropicrin + Telone II on killing the pupae and preventing adult emergence of apple maggot fly, Rhagoletis pomonella (Walsh) was determined. In an e...

  7. Phospha-fluorescein: a red-emissive fluorescein analogue with high photobleaching resistance.

    PubMed

    Fukazawa, Aiko; Suda, Shinji; Taki, Masayasu; Yamaguchi, Eriko; Grzybowski, Marek; Sato, Yoshikatsu; Higashiyama, Tetsuya; Yamaguchi, Shigehiro

    2016-01-01

    Phospha-fluorescein (POF), a phosphine oxide-containing analogue of fluorescein, was synthesized and its photophysical properties were examined. Compared with fluorescein and sila-fluorescein, POF displayed significantly red-shifted absorption and fluorescence as well as superior photobleaching resistance, while retaining the pH-responsive characteristics of fluorescein dyes. PMID:26617335

  8. DOI: 10.1002/adsc.200900134 Stability of Second Generation Grubbs Alkylidenes to Primary

    E-print Network

    Sottos, Nancy R.

    - ence of most common functional groups including ke- tones, aldehydes, alcohols, acids and even water.[1 derivatives, the tricyclohexyl- phosphine (PCy3) ligand is displaced by n-butyl- ACHTUNGTRENNUNGamine is not displaced by pri- mary amines present in up to 100 equivalents. The result is the formation of new stable

  9. Plasma deposition of amorphous metal alloys

    DOEpatents

    Hays, Auda K. (Albuquerque, NM)

    1986-01-01

    Amorphous metal alloy coatings are plasma-deposited by dissociation of vapors of organometallic compounds and metalloid hydrides in the presence of a reducing gas, using a glow discharge. Tetracarbonylnickel, phosphine, and hydrogen constitute a typical reaction mixture of the invention, yielding a NiPC alloy.

  10. Detectionand Classification of Insect Sounds in a GrainSilo using a Neural Network

    E-print Network

    Slatton, Clint

    and external vibrations add noise to the system. A time-delayneural network with feature extraction was successfullytrained to distinguish between thesefour classes of sounds. 1. Introduction The agricultural community, specifically phosphine, hydrocyanic gas and methyl bromide. It is both costly and dangerous to use

  11. Time-Resolved Infrared Spectroscopic Study of Reactive Acyl Intermediates Relevant to Cobalt-Catalyzed Carbonylations1

    E-print Network

    Bernhard, Stefan

    is relevant to the mechanism of the catalysis of alkene hydroformylation by the phosphine- modified cobalt of the chemical industry since the discovery of homogeneous cobalt carbonyl catalysts for alkene hydroformylation in 1938 by Otto Roelen at Ruhrchemie AG.2,3 The original hydroformylation catalysts were based on simple

  12. A Convenient Synthetic Protocol to 1,2-Bis(dialkylphosphino)ethanes

    PubMed Central

    Doyle, Laurence R; Heath, Alex; Low, Choon Heng; Ashley, Andrew E

    2014-01-01

    1,2-Bis(dialkylphosphino)ethanes are readily prepared from the parent phosphine oxides, via a novel sodium aluminium hydride/sodium hydride reduction protocol of intermediate chlorophosphonium chlorides. This approach is amenable to multi-gram syntheses, utilises readily available and inexpensive reagents, and benefits from a facile non-aqueous work-up in the final reductive step. PMID:26190960

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

    PubMed

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

    2014-11-24

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

  14. Highly regioselective osmium-catalyzed hydroformylation.

    PubMed

    Wu, Lipeng; Liu, Qiang; Spannenberg, Anke; Jackstell, Ralf; Beller, Matthias

    2015-02-21

    The first highly regioselective and general osmium-catalyzed hydroformylation of olefins to aldehydes is reported. The combination of Os3(CO)12 and imidazoyl-substituted phosphine ligands allows n-selective (up to 99%) hydroformylation of bulk aliphatic as well as functional alkenes in good yields (64-87%). PMID:25620413

  15. Phosphorus chemistry on Titan

    NASA Astrophysics Data System (ADS)

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

    2011-04-01

    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.

  16. Aggregation-induced emission of a novel conjugated phosphonium salt and its application in mitochondrial imaging

    NASA Astrophysics Data System (ADS)

    Chen, Wen-dan; Zhang, Da-wei; Gong, Wei-tao; Lin, Yuan; Ning, Gui-ling

    2013-06-01

    A new conjugated phosphonium salt TPP was synthesized readily from phosphine-triggered ring-opening of 2,4,5-triphenylpyrylium salt. In aqueous solution, it exhibited interesting AIEE properties and self-assembled into fluorescent nanoparticles, which can be used as a fluorescence probe to image mitochondria in cells.

  17. 40 CFR 721.10370 - Phosphonic acid, p-octyl-, lanthanum (3+) salt (2:1).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...Phosphonic acid, p-octyl-, lanthanum (3+) salt (2:1). 721.10370 Section 721...Phosphonic acid, p-octyl-, lanthanum (3+) salt (2:1). (a) Chemical substance...phosphinic acid, p-octyl-, lanthanum (3+) salt (2:1) (PMN P-10-99; CAS...

  18. 40 CFR 721.10370 - Phosphonic acid, p-octyl-, lanthanum (3+) salt (2:1).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...Phosphonic acid, p-octyl-, lanthanum (3+) salt (2:1). 721.10370 Section 721...Phosphonic acid, p-octyl-, lanthanum (3+) salt (2:1). (a) Chemical substance...phosphinic acid, p-octyl-, lanthanum (3+) salt (2:1) (PMN P-10-99; CAS...

  19. Efficient Domino Hydroformylation/Benzoin Condensation: Highly Selective Synthesis of ?-Hydroxy Ketones.

    PubMed

    Dong, Kaiwu; Sang, Rui; Soule, Jean-Francois; Bruneau, Christian; Franke, Robert; Jackstell, Ralf; Beller, Matthias

    2015-12-01

    An improved domino hydroformylation/benzoin condensation to give ?-hydroxy ketones has been developed. Easily available olefins are smoothly converted into the corresponding ?-hydroxy ketones in high yields with excellent regioselectivities. Key to success is the use of a specific catalytic system consisting of a rhodium/phosphine complex and the CO2 adduct of an N-heterocyclic carbene. PMID:26503672

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

    E-print Network

    Bluemel, Janet

    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

  1. 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...

  2. Tuesday, March 24, 2009 POSTER SESSION I: JUPITER AND INSCRUTABLE IO

    E-print Network

    Rathbun, Julie A.

    Tuesday, March 24, 2009 POSTER SESSION I: JUPITER AND INSCRUTABLE IO 6:30 p.m. Town Center Exhibit Area Visscher C. Sperier A. D. Moses J. I. Keane T. C. Phosphine and Ammonia Photochemistry in Jupiter's Troposphere [#1201] A photochemical model is developed for Jupiter's troposphere using updated constraints

  3. Role of magic-sized clusters in the synthesis of CdSe nanorods.

    PubMed

    Jiang, Zhong-Jie; Kelley, David F

    2010-03-23

    The dynamics of the CdSe nanorod synthesis reaction have been studied, giving attention to the kinetics of magic-sized clusters (MSCs) that form as intermediates in the overall reaction. The MSCs have a distinct absorption peak, and the kinetics of this peak give insight into the overall reaction mechanism. In these studies, the reaction mixture consists primarily of Cd(phosphonate)(2) and trioctyl phosphine selenium in a solution of trioctylphosphine (TOP) and trioctylphosphine oxide (TOPO). We find that the rate at which precursors react to form CdSe monomers and the rates at which monomers react to form nanoparticles can be varied by changing the chemistry of the reaction mixture. Decreasing the TOP concentration decreases the extent to which selenium is bound, both in the precursors and on the particles' surfaces, and thereby increases both the precursor to monomer and monomer to particle reaction rates. Decreasing the phosphonate concentration decreases the extent to which phosphonate binds cadmium in the precursors and on the surface of the nanoparticles, also increasing the rates of both reactions. This is also accomplished by the addition of inorganic acids which protonate the phosphonates. The presence of inorganic acids (impurities) is the primary reason that the overall synthesis reaction is faster in solutions made with technical grade rather than purified TOPO. The TOP and phosphonic acid concentrations are coupled because excess phosphonic acids react with TOP, forming TOPO and less strongly binding species, specifically phosphinic acids, phosphine oxides, and phosphines. PMID:20192241

  4. Synthesis and Characterization of Osmium(II) Trispyrazolylborate Paul W. Dickinson and Gregory S. Girolami*

    E-print Network

    Girolami, Gregory S.

    Synthesis and Characterization of Osmium(II) Trispyrazolylborate Complexes Paul W. Dickinson and actinides.4,5 Polypyrazolylborate osmium complexes remain less ex- plored than those of most other d reagents have also been used to prepare several osmium complexes bearing phosphine ligands; occasionally

  5. Reveille V - 10 

    E-print Network

    Linker Mills

    2006-01-01

    -coupling catalysts, and (3) the investigation of the coordinating strengths of phosphine linkers at Pd centers. Solid-state NMR spectroscopy, a very versatile and comprehensive tool for the study of a wide range of materials, is at the center of this research. First...

  6. Synthesis of Chiral Hydroxyl Phospholanes from D-mannitol and Their Use in Asymmetric Catalytic Reactions

    E-print Network

    Zhang, Xumu

    Synthesis of Chiral Hydroxyl Phospholanes from D-mannitol and Their Use in Asymmetric Catalytic Reactions Wenge Li, Zhaoguo Zhang, Dengming Xiao, and Xumu Zhang* Department of Chemistry, The Pennsylvania explored. Rate acceleration in the Baylis-Hillman reaction was observed when a hydroxyl phosphine was used

  7. On the Mechanism of the Palladium(II)-Catalyzed Decarboxylative Olefination of Arene Carboxylic Acids.

    E-print Network

    On the Mechanism of the Palladium(II)-Catalyzed Decarboxylative Olefination of Arene Carboxylic Acids. Crystallographic Characterization of Non-Phosphine Palladium(II) Intermediates and Observation of a palladium-mediated decarboxylative olefination of arene carboxylic acids are presented, providing

  8. Palladium-Catalyzed Direct Functionalization of Imidazolinone: Synthesis of Dibromophakellstatin

    E-print Network

    Chen, Chuo

    Palladium-Catalyzed Direct Functionalization of Imidazolinone: Synthesis of Dibromophakellstatin arylation of imidazolinone (1) with 6 different palladium sources, 15 different phosphine ligands, 12 of palladium(0) to aryl bromide in these cases. For the synthesis of dibromophakellstatin, phthalimide 11 can

  9. Peptide-coated semiconductor nanocrystals for biomedical applications

    E-print Network

    Michalet, Xavier

    emission spectra, their photostability, brightness and quantum yield make them serious contenders as ideal such as oligomeric phosphines7 , dendrimers8 , amphiphilic polymers9 triblock copolymers10 and peptides1 , (ii) encapsulation in silica shells11, 12 , phospholipid micelles13 , polymer beads14 , polymer shells15

  10. Two-electron mixed-valence complexes small molecule activation and photocatalytic hydrogen production

    E-print Network

    Heyduk, Alan F. (Alan Frank), 1974-

    2001-01-01

    Two-electron mixed-valence complexes of rhodium may be supported by diphosphazane ligands (RN(PY2)2). Whereas diphosphazane ligands with strongly [pi]-acidic phosphine groups (Y = F, OCH2CF3) react with RhI starting materials ...

  11. Demonstration of planar thick InP layers by selective MOVPE N. Dupuis a,, J. Decobert a

    E-print Network

    Lagrée, Pierre-Yves

    . The InP buffer layer avoids starting the epitaxial growth directly with a quaternary material, typically fabrication. In this paper, we focus on the selective area growth conditions of thick InP layers in order in wafers using trimethy- lindium (TMIn), arsine (AsH3), and phosphine (PH3) as growth precursors. The InP

  12. Stereospecific SN2@P reactions: novel access to bulky P-stereogenic ligands.

    PubMed

    Orgué, Sílvia; Flores-Gaspar, Areli; Biosca, Maria; Pàmies, Oscar; Diéguez, Montserrat; Riera, Antoni; Verdaguer, Xavier

    2015-12-01

    The stereospecific hydrolysis of bulky aminophosphine boranes is reported for the first time. The resulting phosphinous acid boranes, upon activation, undergo stereospecific nucleophilic substitution reaction at the phosphorous center with amine nucleophiles. The combination of these two processes provides a novel access to bulky P*-ligands. PMID:26477668

  13. Synthesis and Migratory-Insertion Reactivity of CpMo(CO)[subscript3](CH[subscript3]): Small-Scale Organometallic Preparations Utilizing Modern Glovebox Techniques

    ERIC Educational Resources Information Center

    Whited, Matthew T.; Hofmeister, Gretchen E.

    2014-01-01

    Experiments are described for the reliable small-scale glovebox preparation of CpMo(CO)[subscript 3](CH[subscript 3]) and acetyl derivatives thereof through phosphine-induced migratory insertion. The robust syntheses introduce students to a variety of organometallic reaction mechanisms and glovebox techniques, and they are easily carried out…

  14. Ligand Effects on Optical Properties of Small Gold Clusters: A TDDFT Satyender Goel,,,

    E-print Network

    Tretiak, Sergei

    Density Functional Theory. We study in detail the absorption profile of bare and ligated small gold ligated with phosphine or thiol ligands, in agreement with preliminary experimental data. TPSS fails and biological luminophores. As such, these applications have been the motivating factor behind the significant

  15. The 1982 NASA/ASEE summer faculty fellowship research program, abstracts of research projects, 1st and 2nd-year fellows

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Phosphine photolysis in Jupiter's atmosphere is discussed in relation to organic chemical evolution. Workload in AFTI F-16 test flights, infrared observations of M17, and the relation between rock and vegetation types are presented. Orbiter transfer vehicle aerothermodynamics simulation problems are also discussed.

  16. Vicinal ?,?-functionalizations of amines: cyclization versus dehydrogenative hydrolysis.

    PubMed

    Jiang, Fan; Achard, Mathieu; Bruneau, Christian

    2015-10-01

    Direct vicinal ?,?-difunctionalization of tertiary cyclic amines is achieved in the presence of ruthenium or iridium transition-metal complexes featuring phosphine-sulfonate chelates. By varying the reaction conditions, ?-alkylated lactams were obtained by a formal dehydrogenative hydrolysis in which one molecule of hydrogen is generated from water. PMID:26385286

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

    PubMed Central

    2013-01-01

    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

  18. Coordination-insertion copolymerization of allyl monomers with ethylene.

    PubMed

    Ito, Shingo; Kanazawa, Masafumi; Munakata, Kagehiro; Kuroda, Jun-ichi; Okumura, Yoshikuni; Nozaki, Kyoko

    2011-02-01

    Coordination-insertion copolymerization of allyl monomers with ethylene was developed by using a palladium/phosphine-sulfonate catalyst. A variety of allyl monomers, including allyl acetate, allyl alcohol, protected allylamines, and allyl halides, were copolymerized with ethylene to form highly linear copolymers that possess in-chain -CH(2)CH(CH(2)FG)- units. PMID:21204540

  19. Aluminum hypophosphite microencapsulated to improve its safety and application to flame retardant polyamide 6.

    PubMed

    Ge, Hua; Tang, Gang; Hu, Wei-Zhao; Wang, Bi-Bo; Pan, Ying; Song, Lei; Hu, Yuan

    2015-08-30

    Aluminum hypophosphite (AHP) is an effective phosphorus-containing flame retardant. But AHP also has fire risk that it will decompose and release phosphine which is spontaneously flammable in air and even can form explosive mixtures with air in extreme cases. In this paper, AHP has been microencapsulated by melamine cyanurate (MCA) to prepare microencapsulated aluminum hypophosphite (MCAHP) with the aim of enhancing the fire safety in the procedure of production, storage and use. Meanwhile, MCA was a nitrogen-containing flame retardant that can work with AHP via the nitrogen-phosphorus synergistic effect to show improved flame-retardant property than other capsule materials. After microencapsulation, MCA presented as a protection layer inhibit the degradation of AHP and postpone the generation of phosphine. Furthermore, the phosphine concentration could be effectively diluted by inert decomposition products of MCA. These nonflammable decomposition products of MCA could separate phosphine from air delay the oxidizing reaction with oxygen and decrease the heat release rate, which imply that the fire safety of AHP has been improved. Furthermore, MCAHP was added into polyamide 6 to prepare flame retardant polyamide 6 composites (FR-PA6) which show good flame retardancy. PMID:25867591

  20. Merging Gold and Organocatalysis: A Facile Asymmetric Synthesis of Annulated Pyrroles

    PubMed Central

    Hack, Daniel; Loh, Charles C J; Hartmann, Jan M; Raabe, Gerhard; Enders, Dieter

    2014-01-01

    The combination of cinchona-alkaloid-derived primary amine and AuI–phosphine catalysts allowed the selective C—H functionalization of two adjacent carbon atoms of pyrroles under mild reaction conditions. This sequential dual activation provides seven-membered-ring-annulated pyrrole derivatives in excellent yields and enantioselectivities. PMID:24590817

  1. The Astrophysical Journal, 680: L121L124, 2008 June 20 2008. The American Astronomical Society. All rights reserved. Printed in U.S.A.

    E-print Network

    Ziurys, Lucy M.

    (phosphine) at 267 GHz towardJ p 1 r 0K 0 0 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 -- circumstellar matter -- ISM: molecules -- radio lines: stars -- stars: individual (CRL 2688, IRC 10216) 1

  2. A Mild C-O Bond Formation Catalyzed by a Rhenium-Oxo Complex Benjamin D. Sherry, Alexander T. Radosevich, and F. Dean Toste*

    E-print Network

    Toste, Dean

    A Mild C-O Bond Formation Catalyzed by a Rhenium-Oxo Complex Benjamin D. Sherry, Alexander T to terminal propargyl alcohols.5b Herein, we describe the development and application of a rhenium hindered. A rhenium(V)-oxo complex bearing a bidentate phosphine ligand (dppm ) diphenylphosphinomethane

  3. The Isomerization Equilibrium between Cis and Trans Chloride Ruthenium Olefin Metathesis Catalysts from Quantum Mechanics Calculations

    E-print Network

    Goddard III, William A.

    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

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

    PubMed Central

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

    2015-01-01

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

  5. Development of a Lewis Base Catalyzed Selenocyclization Reaction

    ERIC Educational Resources Information Center

    Collins, William

    2009-01-01

    The concept of Lewis base activation of selenium Lewis acids has been effectively reduced to practice in the Lewis base catalyzed selenofunctionalization of unactivated olefins. In this reaction, the weakly acidic species, "N"-phenylselenyl succinimide, is cooperatively activated by the addition of a "soft" Lewis base donor (phosphine sulfides,…

  6. 40 CFR 180.284 - Zinc phosphide; tolerances for residues.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Zinc phosphide; tolerances for... § 180.284 Zinc phosphide; tolerances for residues. (a) General. Tolerances are established for residues of the phosphine resulting from the use of the rodenticide zinc phosphide in or on the...

  7. 40 CFR 180.284 - Zinc phosphide; tolerances for residues.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Zinc phosphide; tolerances for... § 180.284 Zinc phosphide; tolerances for residues. (a) General. Tolerances are established for residues of the phosphine resulting from the use of the rodenticide zinc phosphide in or on the...

  8. 40 CFR 180.284 - Zinc phosphide; tolerances for residues.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Zinc phosphide; tolerances for... § 180.284 Zinc phosphide; tolerances for residues. (a) General. Tolerances are established for residues of the phosphine resulting from the use of the rodenticide zinc phosphide in or on the...

  9. 40 CFR 180.284 - Zinc phosphide; tolerances for residues.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Zinc phosphide; tolerances for... § 180.284 Zinc phosphide; tolerances for residues. (a) General. Tolerances are established for residues of the phosphine resulting from the use of the rodenticide zinc phosphide in or on the...

  10. 40 CFR 180.284 - Zinc phosphide; tolerances for residues.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Zinc phosphide; tolerances for... § 180.284 Zinc phosphide; tolerances for residues. (a) General. Tolerances are established for residues of the phosphine resulting from the use of the rodenticide zinc phosphide in or on the...

  11. 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

  12. A Broadly Applicable Strategy for Entry into Homogeneous Nickel(0) Catalysts from Air-Stable Nickel(II) Complexes

    E-print Network

    Müller, Peter

    A Broadly Applicable Strategy for Entry into Homogeneous Nickel(0) Catalysts from Air-Stable Nickel ABSTRACT: A series of air-stable nickel complexes of the form L2Ni(aryl) X (L = monodentate phosphine, X of precatalysts suitable for a wide variety of nickel-catalyzed transformations. These complexes are easily

  13. & Nickel Complexes Monometallic Ni0

    E-print Network

    Bluemel, Janet

    & Nickel Complexes Monometallic Ni0 and Heterobimetallic Ni0 /AuI Complexes of Tripodal Phosphine Bhuvanesh, and Janet Blümel*[a] Abstract: The tridentate chelate nickel complexes [(CO)Ni- {(PPh2CH2)3CMe- lysts,[3] Pd0 /CuI Sonogashira systems for CÀC cross-coupling re- actions,[4] and nickel catalysts

  14. Catalytic Carbon-Carbon and Carbon-Silicon Bond Activation and Functionalization by Nickel Complexes

    E-print Network

    Jones, William D.

    Catalytic Carbon-Carbon and Carbon-Silicon Bond Activation and Functionalization by Nickel of Rochester, Rochester, New York 14627 Received June 11, 1999 The nickel alkyne complexes (dippe)Ni(Me3Si, and nickel phosphine complexes.3 Milstein and co-workers reported the cata- lytic hydrogenolysis

  15. Catalytic Carbon-Carbon Bond Activation and Functionalization by Nickel Complexes

    E-print Network

    Jones, William D.

    Catalytic Carbon-Carbon Bond Activation and Functionalization by Nickel Complexes Brian L. Edelbach, New York 14627 Received May 24, 1999 The nickel alkyne complexes (dippe)Ni(PhCtCPh), 1, (dippe reported using (C5Me5)Rh- (PMe3)H2 5e and several platinum, palladium, and nickel phosphine complexes.5i

  16. 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...

  17. 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

    Paterniti, D.P.; Francisco, L.W.; Atwood, J.D.

    1999-01-18

    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.

  18. Extracting metals directly from metal oxides

    DOEpatents

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

    1997-01-01

    A method of extracting metals directly from metal oxides by exposing the oxide to a supercritical fluid solvent containing a chelating agent is described. Preferably, the metal is an actinide or a lanthanide. More preferably, the metal is uranium, thorium or plutonium. The chelating agent forms chelates that are soluble in the supercritical fluid, thereby allowing direct removal of the metal from the metal oxide. In preferred embodiments, the extraction solvent is supercritical carbon dioxide and the chelating agent is selected from the group consisting of .beta.-diketones, halogenated .beta.-diketones, phosphinic acids, halogenated phosphinic acids, carboxylic acids, halogenated carboxylic acids, and mixtures thereof. In especially preferred embodiments, at least one of the chelating agents is fluorinated. The method provides an environmentally benign process for removing metals from metal oxides without using acids or biologically harmful solvents. The chelate and supercritical fluid can be regenerated, and the metal recovered, to provide an economic, efficient process.

  19. Extracting metals directly from metal oxides

    DOEpatents

    Wai, C.M.; Smart, N.G.; Phelps, C.

    1997-02-25

    A method of extracting metals directly from metal oxides by exposing the oxide to a supercritical fluid solvent containing a chelating agent is described. Preferably, the metal is an actinide or a lanthanide. More preferably, the metal is uranium, thorium or plutonium. The chelating agent forms chelates that are soluble in the supercritical fluid, thereby allowing direct removal of the metal from the metal oxide. In preferred embodiments, the extraction solvent is supercritical carbon dioxide and the chelating agent is selected from the group consisting of {beta}-diketones, halogenated {beta}-diketones, phosphinic acids, halogenated phosphinic acids, carboxylic acids, halogenated carboxylic acids, and mixtures thereof. In especially preferred embodiments, at least one of the chelating agents is fluorinated. The method provides an environmentally benign process for removing metals from metal oxides without using acids or biologically harmful solvents. The chelate and supercritical fluid can be regenerated, and the metal recovered, to provide an economic, efficient process. 4 figs.

  20. Toroid NMR probes for the in situ examination of homogeneous cobalt hydroformylation catalysts at high pressures and temperatures.

    SciTech Connect

    Kramarz, K. W.; Klingler, R. J.; Fremgen, D. E.; Rathke, J. W.; Chemical Engineering

    1999-03-01

    Toroid NMR probes can be routinely operated at 300 atm and up to 250 C. Such operating conditions make these probes well suited for the in situ examination of catalytic industrial processes. These probes have been employed to examine phosphine substituted (Shell-type) and unsubstituted cobalt carbonyl oxo catalysts under catalytic and non-catalytic conditions in a variety of solvents. The solvents include cyclohexane, benzene, dioxane, 2-methylpropanol, supercritical carbon dioxide (scCO{sub 2}), and scCO{sub 2}/toluene mixtures. The high-pressure/high-temperature probes allowed the observation of precatalytic equilibria under high carbon monoxide pressures in the presence and absence of hydrogen and/or free phosphine.

  1. Palladium-catalyzed isomerization and hydroformylation of olefins.

    PubMed

    Jennerjahn, Reiko; Piras, Irene; Jackstell, Ralf; Franke, Robert; Wiese, Klaus-Diether; Beller, Matthias

    2009-06-22

    A novel selective palladium catalyst system based on bidentate 2,2'-heteroarylarylphosphines and p-TsOH has been developed for hydroformylation reactions (see scheme). By applying optimal conditions good to excellent regioselectivity is obtained for the hydroformylation of aliphatic and aromatic olefins. It is shown that a low acid concentration is crucial for obtaining high degrees of the linear isomer.The palladium-catalyzed hydroformylation of 1-octene has been studied in the presence of different phosphines and acid cocatalysts. The best results are achieved in the presence of in situ-generated palladium complexes with bidentate phosphines. It is demonstrated that the acid concentration is a crucial factor for obtaining high linear selectivity. A novel optimized catalyst based on an arylheteroarylphosphine has been applied for hydroformylation of different aliphatic and aromatic olefins. Good activity and excellent selectivity towards the linear aldehydes is achieved. PMID:19466732

  2. On the compensation mechanism of amorphous silicon films: Study of stability

    SciTech Connect

    Caputo, D.; De Cesare, G.; Palma, F.; Tucci, M.; Minarini, C.; Terzini, E.

    1997-07-01

    The authors investigated a-Si:H compensated materials deposited over a wide range of gas dopant concentrations, from 0.125 ppm up to 10{sup 3} ppm. They achieved compensation for different ratio in the gas phase of diborane and phosphine, depending on their concentration. As a relevant result, they found that at constant boron concentration compensation occurs by using two different values of phosphine flow. This behavior can be described by a change of formation mechanism involving active dopants, defects and boron-phosphorus complex, that occurs in a different way depending on the dopant concentrations. The two compensation regimes are evidenced also by a different behavior under light soaking. Furthermore they found that photocurrent evolution under illumination is determined by two concurrent mechanisms: activation of dopant species and increase of defect density.

  3. Bis(pentamethylcyclopentadienyl)ytterbium: An investigation of weak interactions in solution using multinuclear NMR spectroscopy

    SciTech Connect

    Schwartz, D.J.

    1995-07-01

    NMR spectroscopy is ideal for studying weak interactions (formation enthalpy {le}20 kcal/mol) in solution. The metallocene bis(pentamethylcyclopentadienyl)ytterbium, Cp*{sub 2}Yb, is ideal for this purpose. cis-P{sub 2}PtH{sub 2}complexes (P = phosphine) were used to produce slow-exchange Cp*{sub 2}YbL adducts for NMR study. Reversible formation of (P{sub 2}PtH){sub 2} complexes from cis-P{sub 2}PtH{sub 2} complexes were also studied, followed by interactions of Cp*{sub 2}Yb with phosphines, R{sub 3}PX complexes. A NMR study was done on the interactions of Cp*{sub 2}Yb with H{sub 2}, CH{sub 4}, Xe, CO, silanes, stannanes, C{sub 6}H{sub 6}, and toluene.

  4. 2-(Diphenyl­phosphinoylmeth­yl)pyrrole–2-(diphenyl­phosphinometh­yl)pyrrole (0.43/0.57) and tetra­chlorido­(5-diphenyl­phosphinometh­yl-2H-pyrrole-?2 N,P)titanium(IV)

    PubMed Central

    Broomfield, Lewis M.; Bochmann, Manfred; Wright, Joseph A.

    2010-01-01

    The title phosphine oxide–phosphine, 0.43C17H16NOP·0.57C17H16NP, (I)/(II), was obtained as a 0.861?(6):1.139?(6) cocrystallized mixture. Hydrogen bonding between the two constituents leads to the formation of 2:2 solid-state assemblies. Instead of forming the expected simple N,P-chelated system via loss of the N-bound H atom, reaction of 2-(diphenyl­phosphinometh­yl)pyrrole, (II), with TiCl4 leads to the formation of the title titanium(IV) complex, [TiCl4(C17H16NP)], (IV), containing a rearranged neutral ligand in which the N-bound H atom moves to one of the pyrrole C atoms, giving a partially unsaturated ring. PMID:20203400

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

    SciTech Connect

    Not Available

    1995-12-31

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

  6. Feasibility of actinide separation from UREX-like raffinates using a combination of sulfur- and oxygen-donor extractants

    SciTech Connect

    Zalupski, P.R.; Peterman, D.R.; Riddle, C.L.

    2013-07-01

    A synergistic combination of bis(o-trifluoromethylphenyl)dithios-phosphinic acid and trioctylphosphine oxide has been recently shown to selectively remove uranium, neptunium, plutonium and americium from aqueous environment containing up to 0.5 M nitric acid and 5.5 g/l fission products. Here the feasibility of performing this complete actinide recovery from aqueous mixtures is forecasted for a new organic formulation containing sulfur donor extractant of modified structure based on Am(III) and Eu(III) extraction data. A mixture of bis(bis-m,m-trifluoromethyl)phenyl)-dithios-phosphinic acid and TOPO in toluene enhances the extraction performance, accomplishing Am/Eu differentiation in aqueous mixtures up to 1 M nitric acid. The new organic recipe is also less susceptible to oxidative damage resulting from radiolysis. (authors)

  7. Trace Species Identified in Saturn's Northern Storm Region

    NASA Technical Reports Server (NTRS)

    Bjoraker, Gordon L.; Hesman, B. E.; Achterberg, R. K.

    2011-01-01

    The massive storm at 40degN on Saturn that began in December 2010 has produced significant and lasting effects in the northern hemisphere on temperature and species abundances [I}. The northern storm region was observed at 0.5/cm spectral resolution in March 2011 by Cassini's Composite Infrared Spectrometer (CIRS). Temperatures in the stratosphere as high as 190 K were derived from CIRS spectra in warm regions referred to as "beacons". Other longitudes exhibit cold temperatures in the upper troposphere. These unusual conditions allow us to identify rare species such as C4H2, C3H4, and CO2 in the stratosphere, as well as to measure changes in the abundance of phosphine (PH3) in the troposphere. Phosphine is a disequilibrium species whose abundance is a tracer of upwelling from the deep atmosphere.

  8. A comprehensive study of olefin metathesis catalyzed by Ru-based catalysts.

    PubMed

    Poater, Albert; Cavallo, Luigi

    2015-01-01

    During a Ru-catalyzed reaction of an olefin with an alkylidene moiety that leads to a metallacycle intermediate, the cis insertion of the olefin can occur from two different directions, namely side and bottom with respect to the phosphine or N-heterocyclic ligand (NHC), depending on the first or second generation Grubbs catalyst. Here, DFT calculations unravel to which extent the bottom coordination of olefins with respect is favored over the side coordination through screening a wide range of catalysts, including first and second generation Grubbs catalysts as well as the subsequent Hoveyda derivatives. The equilibrium between bottom and side coordination is influenced by sterics, electronics, and polarity of the solvent. The side attack is favored for sterically less demanding NHC and/or alkylidene ligands. Moreover the generation of a 14-electron species is also discussed, with either pyridine or phosphine ligands to dissociate. PMID:26664596

  9. A comprehensive study of olefin metathesis catalyzed by Ru-based catalysts

    PubMed Central

    2015-01-01

    Summary During a Ru-catalyzed reaction of an olefin with an alkylidene moiety that leads to a metallacycle intermediate, the cis insertion of the olefin can occur from two different directions, namely side and bottom with respect to the phosphine or N-heterocyclic ligand (NHC), depending on the first or second generation Grubbs catalyst. Here, DFT calculations unravel to which extent the bottom coordination of olefins with respect is favored over the side coordination through screening a wide range of catalysts, including first and second generation Grubbs catalysts as well as the subsequent Hoveyda derivatives. The equilibrium between bottom and side coordination is influenced by sterics, electronics, and polarity of the solvent. The side attack is favored for sterically less demanding NHC and/or alkylidene ligands. Moreover the generation of a 14-electron species is also discussed, with either pyridine or phosphine ligands to dissociate. PMID:26664596

  10. Synthesis of uniform-sized bimetallic iron-nickel phosphide nanorods

    SciTech Connect

    Yoon, Ki Youl; Jang, Youngjin; Park, Jongnam; Hwang, Yosun; Koo, Bonil; Park, Je-Geun; Hyeon, Taeghwan

    2008-07-15

    We synthesized uniform-sized nanorods of iron-nickel phosphides from the thermal decomposition of metal-phosphine complexes. Uniform-sized (Fe{sub x}Ni{sub 1-x}){sub 2}P nanorods (0{<=}x{<=}1) of various compositions were synthesized by thermal decomposition of Ni-trioctylphosphine (TOP) complex and Fe-TOP complex. By measuring magnetic properties, we found that blocking temperature and coercive field depend on Ni content in the nanorods. Both parameters were more sensitive to doping compared with bulk samples. - Graphical abstract: We synthesized uniform-sized nanorods of iron-nickel phosphides from thermal decomposition of metal-phosphine complexes. The magnetic studies showed that blocking temperature and coercive field depend on Ni content in the nanorods.

  11. Tetra­methyl 1,1,2-triphenyl-2H-1?5-phosphole-2,3,4,5-tetra­carboxyl­ate

    PubMed Central

    Krawczyk, Krzysztof K.; Wojtasiewicz, Krystyna; Maurin, Jan K.; Gronowska, Ewa; Czarnocki, Zbigniew

    2010-01-01

    The title compound, C30H27O8P (1), was formed as one of two products {(1) and (2) [Krawczyk et al. (2010 ?). Acta Cryst. E66 (cv2753)]} in the reaction of dimethyl acetyl­enedicarboxyl­ate with triphenyl­phosphine. The mol­ecule of (1) consists of a five-membered ring, in which the P atom is incorporated. One of the phenyl groups of the triphenyl­phosphine migrated to a vicinal C atom during the reaction. The five-membered ring of (1) is corrugated [r.m.s. deviation = 0.0719?(8)?Å], whereas that in compound (2) is planar, the r.m.s. deviation being only 0.009?(2)?Å. PMID:21588988

  12. Improved performance of nanocrystal quantum dots-based LEDs by modifying hole transport layer.

    PubMed

    Lee, Jihye; Han, Chang-Soo; Jeong, Sohee; Kang, Byoung-Ho; Hong, Seok-Min; Kim, Do-Eok; Kang, Shin-Won

    2011-01-01

    Reported herein are the effects of the fabrication variables and surface capping of nanocrystal quantum dots (NQDs) on the characteristics of NQDs-based light-emitting diodes (LEDs). The molecular weight of the hole transport layer (HTL) material and the annealing conditions of the NQDs layer were chosen as fabrication process variables. Their effects on the layer characteristics and device efficiency were characterized. The maximum brightness varied over 50% according to the molecular weight of the HTL material. The optimized annealing temperature was shown to improve the maximum brightness by 20%. The surface-capping molecules of the NQDs were changed from conventional trioctyl phosphine/trioctyl phosphine oxide (TOPO/TOP) to pyridine and were incorporated into LEDs, and its effects on the device characteristics were discussed. PMID:21446470

  13. Coordination Chemistry of Cyclic Disilylated Stannylenes and Plumbylenes to Group 4 Metallocenes

    PubMed Central

    2012-01-01

    Reduction of group 4 metallocene dichlorides with magnesium in the presence of cyclic disilylated stannylene or plumbylene phosphine adducts yielded the respective metallocene tetrylene phosphine complexes. Under the same conditions the use of the respective dimerized stannylene or plumbylene gave metallocene ditetrylene complexes. A computational analysis of these reactions revealed for all investigated compounds multiple-bonded character for the M–E(II) linkage, which can be rationalized in the case of the monotetrylene complex with the classical ?-donor/?-acceptor interaction. The strength of the M–E(II) bond increases descending group 4 and decreases going from Sn to its heavier congener Pb. The weakness of the Ti–E(II) bonds is caused by the significantly reduced ability of the titanium atom for d–p ?-back-bonding. PMID:22716501

  14. Growth of defect-free GaP nanowires.

    PubMed

    Husanu, Elena; Ercolani, Daniele; Gemmi, Mauro; Sorba, Lucia

    2014-05-23

    The crystal structure of GaP nanowires grown by Au-assisted chemical beam epitaxy was investigated as a function of group V flux and growth temperature. By increasing the tertiarybutyl phosphine flux we obtained nanowires with a stacking defect-free wurtzite crystal structure. Variation of growth temperature also had a profound impact on the crystal structure. Lowering the growth temperature from 600 to 560 °C and keeping constant both triethylgallium and tertiarybutyl phosphine precursor fluxes, the crystal structure of GaP NWs was drastically improved from a highly defective intergrowth of zinc-blende and wurtzite to a wurtzite crystal structure free of stacking defects. These results are compared to current literature on GaP NW growth, and we suggest that the low V/III ratio is the key ingredient for the high crystal quality of our GaP nanowires. PMID:24785358

  15. CuInSe2 Quantum Dot Solar Cells with High Open-Circuit Voltage.

    PubMed

    Panthani, Matthew G; Stolle, C Jackson; Reid, Dariya K; Rhee, Dong Joon; Harvey, Taylor B; Akhavan, Vahid A; Yu, Yixuan; Korgel, Brian A

    2013-06-20

    CuInSe2 (CISe) quantum dots (QDs) were synthesized with tunable size from less than 2 to 7 nm diameter. Nanocrystals were made using a secondary phosphine selenide as the Se source, which, compared to tertiary phosphine selenide precursors, was found to provide higher product yields and smaller nanocrystals that elicit quantum confinement with a size-dependent optical gap. Photovoltaic devices fabricated from spray-cast CISe QD films exhibited large, size-dependent, open-circuit voltages, up to 849 mV for absorber films with a 1.46 eV optical gap, suggesting that midgap trapping does not dominate the performance of these CISe QD solar cells. PMID:26283248

  16. Activation of molecular oxygen by a molybdenum complex for catalytic oxidation.

    PubMed

    Dupé, Antoine; Judmaier, Martina E; Belaj, Ferdinand; Zangger, Klaus; Mösch-Zanetti, Nadia C

    2015-12-21

    A sterically demanding molybdenum(vi) dioxo complex was found to catalytically activate molecular oxygen and to transfer its oxygen atoms to phosphines. Intermediate peroxo as well as reduced mono-oxo complexes were isolated and fully characterized. Monomeric Mo(iv) monooxo species proved to be of an unusual nature with the coordinated phosphine trans to the oxo group. The reduced molybdenum centers can activate O2 to form a stable Mo(vi) oxo-peroxo complex unambiguously characterized by single crystal X-ray diffraction analysis. NMR experiments demonstrate that both oxygen atoms of the peroxo unit are transferred to an accepting substrate, generating the Mo(iv) intermediate and restarting the catalytic cycle. PMID:26548583

  17. Reactivity of Metal Ions Bound to Water-Soluble Polymers

    SciTech Connect

    Sauer, N.N.; Watkins, J.G.; Lin, M.; Birnbaum, E.R.; Robison, T.W.; Smith, B.F.; Gohdes, J.W.; McDonald, J.G.

    1999-06-29

    The intent of this work is to determine the effectiveness of catalysts covalently bound to polymers and to understand the consequences of supporting the catalysts on catalyst efficiency and selectivity. Rhodium phosphine complexes with functional groups for coupling to polymers were prepared. These catalyst precursors were characterized using standard techniques including IR, NMR, and elemental analysis. Studies on the modified catalysts showed that they were still active hydrogenation catalysts. However, tethering of the catalysts to polyamines gave systems with low hydrogenation activity. Analogous biphasic systems were also explored. Phosphine ligands with a surfactant-like structure have been synthesized and used to prepare catalytically active complexes of palladium. The palladium complexes were utilized in Heck-type coupling reactions (e.g. coupling of iodobenzene and ethyl acrylate to produce ethyl cinnamate) under vigorously stirred biphasic reaction conditions, and were found to offer superior performance over a standard water-soluble palladium catalyst under analogous conditions.

  18. Regioselectivity switch achieved in the palladium catalyzed ?-arylation of enones by employing the modified Kuwajima-Urabe conditions.

    PubMed

    Kale, Ajit Prabhakar; Pawar, Govind Goroba; Kapur, Manmohan

    2012-04-01

    A new regioselective approach to the synthesis of ?-aryl enones is reported. This represents an important application of the Kuwajima-Urabe protocol toward the synthesis of this simple albeit complex functional array. Several ?-aryl enones were synthesized by the palladium catalyzed arylation of triethylsilylenol ethers of enones with high regioselectivity and broad scope, utilizing sterically encumbered electron-rich phosphine ligands to drive the reaction. PMID:22432858

  19. Computational kinetics of cobalt-catalyzed alkene hydroformylation.

    PubMed

    Rush, Laura E; Pringle, Paul G; Harvey, Jeremy N

    2014-08-11

    Density functional theory, coupled-cluster theory, and transition state theory are used to build a computational model of the kinetics of phosphine-free cobalt-catalyzed hydroformylation and hydrogenation of alkenes. The model provides very good agreement with experiment, and enables the factors that determine the selectivity and rate of catalysis to be determined. The turnover rate is mainly determined by the alkene coordination step. PMID:24700408

  20. Dynamic tests for actinide/lanthanide separation by CMPO solvent in fluorinated diluents

    SciTech Connect

    Tkachenko, L.; Babain, V.; Alyapyshev, M.; Vizniy, A.; Il'in, A.; Shadrin, A.

    2013-07-01

    Actinide and lanthanide extraction by new solvent: 0.2 M phenyl-octyl-N,N-diiso-butylcarbamoyl-phosphine oxide (CMPO) + 30% TBP + formal of octafluoro-pentanol was studied. A dynamic test with this solvent was performed. It was shown that americium and lanthanides are effectively extracted from PUREX process raffinate. The separation of americium from light lanthanides was confirmed in the modified SETFICS flowsheet with this new solvent. (authors)

  1. Divergent amine-catalyzed [4 + 2] annulation of Morita-Baylis-Hillman allylic acetates with electron-deficient alkenes.

    PubMed

    Xu, Silong; Chen, Rongshun; Qin, Zifeng; Wu, Guiping; He, Zhengjie

    2012-02-17

    An amine-catalyzed [4 + 2] annulation of Morita-Baylis-Hillman allylic acetates 2 with electron-deficient alkenes or diazenes has been developed for efficient syntheses of highly functionalized cyclohexenes, tetrahydropyridazines, and important spirocycles. This reaction unveils a new reactivity pattern of the intensely studied allylic compounds 2 acting as a C(4) synthon in Lewis base catalyzed annulation reactions and also showcases divergent catalysis between tertiary amines and phosphines. PMID:22304572

  2. Synthesis of hcp-Co nanodisks

    SciTech Connect

    Puntes, Victor F.; Zanchet, Daniela; Erdonmez, Can K.; Alivisatos, A.P.

    2002-06-11

    hcp Co disk-shaped nanocrystals were obtained by rapid decomposition of cobalt carbonyl in presence of linear amines. Other surfactants, in addition to the amines, like phosphine oxides and oleic acid were used to improve size dispersion, shape control and nanocrystal stability. Co disks are ferromagnetic in character and they spontaneously self-assemble into long ribbons. X-ray and electron diffraction, electron microscopy and SQUID magnetometry have been employed to characterize this material.

  3. Modular Access to Substituted Azocanes via a Rhodium-Catalyzed Cycloaddition–Fragmentation Strategy

    PubMed Central

    2015-01-01

    A short entry to substituted azocanes by a Rh-catalyzed cycloaddition–fragmentation process is described. Specifically, exposure of diverse N-cyclopropylacrylamides to phosphine-ligated cationic Rh(I) catalyst systems under a CO atmosphere enables the directed generation of rhodacyclopentanone intermediates. Subsequent insertion of the alkene component is followed by fragmentation to give the heterocyclic target. Stereochemical studies show, for the first time, that alkene insertion into rhodacyclopentanones can be reversible. PMID:26090897

  4. Synthesis and Characterization of Gold Clusters Ligated with 1,3-Bis(dicyclohexylphosphino)propane

    SciTech Connect

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

    2013-09-01

    In this multidisciplinary study we combine chemical reduction synthesis of novel gold clusters in solution with high-resolution analytical mass spectrometry (MS) to gain insight into the composition of the gold clusters and how their size, ionic charge state and ligand substitution influences their gas-phase fragmentation pathways. Ultra small cationic gold clusters ligated with 1,3-bis(dicyclohexylphosphino)propane (DCPP) were synthesized for the first time and introduced into the gas phase using electrospray ionization (ESI). Mass-selected cluster ions were fragmented employing collision induced dissociation (CID) and the product ions were analysed using MS. The solutions were found to contain the multiply charged cationic gold clusters Au9L43+, Au13L53+, Au6L32+, Au8L32+ and Au10L42+ (L = DCPP). The gas-phase fragmentation pathways of these cluster ions were examined systematically employing CID combined with MS. In addition, CID experiments were performed on related gold clusters of the same size and ionic charge state but capped with 1,3-bis(diphenylphosphino)propane (DPPP) ligands containing phenyl functional groups at the two phosphine centers instead of cyclohexane rings. It is shown that this relatively small change in the molecular substitution of the two phosphine centers in diphosphine ligands (C6H11 versus C6H5) exerts a pronounced influence on the size of the species that are preferentially formed in solution during reduction synthesis as well as the gas-phase fragmentation channels of otherwise identical gold cluster ions. The mass spectrometry results indicate that in addition to the length of the alkyl chain between the two phosphine centers, the substituents at the phosphine centers also play a crucial role in determining the composition, size and stability of diphosphine ligated gold clusters synthesized in solution.

  5. Surface dilational rheology of mixed beta-lactoglobulin/surfactant layers at the air/water interface.

    PubMed

    Miller, R; Leser, M E; Michel, M; Fainerman, V B

    2005-07-14

    The general theoretical model by Garrett and Joos proposed in 1976 for the estimation of the dilational elasticity of mixed surfactant solutions, and also the theoretical model proposed by Joos for the limiting elasticity of such mixtures, demonstrate quite satisfactory agreement with experimental results obtained from the oscillating bubble shape method for mixtures of a nonionic surfactant and a protein, that is, beta-lactoglobuline and decyl dimethyl phosphine oxide, C10DMPO. PMID:16852663

  6. Synthesis and Decarboxylative Coupling of Sulfonyl Acetic Esters

    E-print Network

    Weaver, Jimmie Dean

    2010-04-28

    make the reaction more tolerant of both ?-H’s and ?-H’s on the allyl component, cyclohex-2-enyl 2-phenyl-2-(phenylsulfonyl)acetate was synthesized. The substrate was first subjected to the standard conditions which required some heating but gave.... In addition to not reaching completion the amount of protonation product increased significantly. The incomplete reaction might be explained if the phosphine ligand is the reductant. If the BINAP ligand is oxidized, it would likely not ligate comparably...

  7. On the Functional Group Tolerance of Ester Hydrogenation and Polyester Depolymerisation Catalysed by Ruthenium Complexes of Tridentate Aminophosphine Ligands.

    PubMed

    Fuentes, José A; Smith, Samuel M; Scharbert, M Theresa; Carpenter, Ian; Cordes, David B; Slawin, Alexandra M Z; Clarke, Matthew L

    2015-07-20

    The synthesis of a range of phosphine-diamine, phosphine-amino-alcohol, and phosphine-amino-amide ligands and their ruthenium(II) complexes are reported. Five of these were characterised by X-ray crystallography. The activities of this collection of catalysts were initially compared for the hydrogenation of two model ester hydrogenations. Catalyst turnover frequencies up to 2400?h(-1) were observed at 85?°C. However, turnover is slow at near ambient temperatures. By using a phosphine-diamine Ru(II) complex, identified as the most active catalyst, a range of aromatic esters were reduced in high yield. The hydrogenation of alkene-, diene-, and alkyne-functionalised esters was also studied. Substrates with a remote, but reactive terminal alkene substituent could be reduced chemoselectively in the presence of 4-dimethylaminopyridine (DMAP) co-catalyst. The chemoselective reduction of the ester function in conjugated dienoate ethyl sorbate could deliver (2E,4E)-hexa-2,4-dien-1-ol, a precursor to leaf alcohol. The monounsaturated alcohol (E)-hex-4-en-1-ol was produced with reasonable selectivity, but complete chemoselectivity of C=O over the diene is elusive. High chemoselectivity for the reduction of an ester over an alkyne group was observed in the hydrogenation of an alkynoate for the first time. The catalysts were also active in the depolymerisation reduction of samples of waste poly(ethylene terephthalate) (PET) to produce benzene dimethanol. These depolymerisations were found to be poisoned by the ethylene glycol side product, although good yields could still be achieved. PMID:26176880

  8. Ruthenium indenylidene "1(st) generation" olefin metathesis catalysts containing triisopropyl phosphite.

    PubMed

    Guidone, Stefano; Nahra, Fady; Slawin, Alexandra M Z; Cazin, Catherine S J

    2015-01-01

    The reaction of triisopropyl phosphite with phosphine-based indenylidene pre-catalysts affords "1(st) generation" cis-complexes. These have been used in olefin metathesis reactions. The cis-Ru species exhibit noticeable differences with the trans-Ru parent complexes in terms of structure, thermal stability and reactivity. Experimental data underline the importance of synergistic effects between phosphites and L-type ligands. PMID:26425210

  9. Ruthenium indenylidene “1st generation” olefin metathesis catalysts containing triisopropyl phosphite

    PubMed Central

    Guidone, Stefano; Nahra, Fady; Slawin, Alexandra M Z

    2015-01-01

    Summary The reaction of triisopropyl phosphite with phosphine-based indenylidene pre-catalysts affords “1st generation” cis-complexes. These have been used in olefin metathesis reactions. The cis-Ru species exhibit noticeable differences with the trans-Ru parent complexes in terms of structure, thermal stability and reactivity. Experimental data underline the importance of synergistic effects between phosphites and L-type ligands. PMID:26425210

  10. Capture of Reactive Monophosphine-Ligated Palladium(0) Intermediates by Mass Spectrometry.

    PubMed

    Zheng, Qiuling; Liu, Yong; Chen, Qinghao; Hu, Meihong; Helmy, Roy; Sherer, Edward C; Welch, Christopher J; Chen, Hao

    2015-11-11

    A long-sought-after reactive monophosphine-ligated palladium(0) intermediate, Pd(0)L (L = phosphine ligand), was detected for the first time from the activation of the Buchwald precatalyst with base. The detection was enabled using desorption electrospray ionization mass spectrometry (DESI-MS) in combination with online reaction monitoring. The subsequent oxidative addition of Pd(0)L with aryl halide and C-N coupling with amine via reductive elimination was also probed using DESI-MS. PMID:26498505

  11. Triple-Helical Transition State Analogs: A New Class of Selective Matrix Metalloproteinase Inhibitors

    PubMed Central

    Lauer-Fields, Janelle; Brew, Keith; Whitehead, John K.; Li, Shunzi; Hammer, Robert P.; Fields, Gregg B.

    2008-01-01

    Alterations in activities of one family of proteases, the matrix metalloproteinases (MMPs), have been implicated in primary and metastatic tumor growth, angiogenesis, and pathological degradation of extracellular matrix (ECM) components, such as collagen and laminin. Since hydrolysis of the collagen triple-helix is one of the committed steps in ECM turnover, we envisioned modulation of collagenolytic activity as a strategy for creating selective MMP inhibitors. In the present study, a phosphinate transition state analog has been incorporated within a triple-helical peptide template. The template sequence was based on the ?1(V)436-450 collagen region, which is hydrolyzed at the Gly439~Val440 bond selectively by MMP-2 and MMP-9. The phosphinate acts as a tetrahedral transition state analog, which mimics the water-bound peptide bond of a protein substrate during hydrolysis. The phosphinate replaced the amide bond between Gly-Val in the P1-P1? subsites of the triple-helical peptide. Inhibition studies revealed Ki values in the low nanomolar range for MMP-2 and MMP-9 and low to middle micromolar range for MMP-8 and MMP-13. MMP-1, MMP-3, and MT1-MMP/MMP-14 were not inhibited effectively. Melting of the triple-helix resulted in a decrease in inhibitor affinity for MMP-2. The phosphinate triple-helical transition state analog has high affinity and selectivity for the gelatinases (MMP-2 and MMP-9), and represents a new class of protease inhibitors that maximizes potential selectivity via interactions with both prime and non-prime active site subsites as well as with secondary binding sites (exosites). PMID:17672455

  12. 78 FR 6274 - Withdrawal of Pesticide Petitions for Residues of Pesticide Chemicals in or on Various Commodities

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-30

    ... issued a notice in the Federal Register of July 6, 2011 (76 FR 39358) (FRL-8875-6) (EPA-HQ-OPP-2010- 0820... notice in the Federal Register of September 23, 2010 (75 FR 57942) (FRL-8845-4) (EPA-HQ-OPP- 2010-0740... (Phosphine). EPA issued a notice in the Federal Register of October 5, 2011 (76 FR 61649) (FRL-8890-5)...

  13. Phosphorus-containing imide resins

    NASA Technical Reports Server (NTRS)

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

    1984-01-01

    Flame-resistant reinforced bodies are disclosed which are composed of reinforcing fibers, filaments or fabrics in a cured body of bis- and tris-imide resins derived from tris(m-aminophenyl) phosphine oxides by reaction with maleic anhydride or its derivatives, or of addition polymers of such imides, including a variant in which a mono-imide is condensed with a dianhydride and the product is treated with a further quantity of maleic anhydride.

  14. Surface accumulation of hydrogen during capless annealing of InP

    SciTech Connect

    Haussler, W.

    1989-06-19

    InP samples, which had received a capless anneal in a phosphine/hydrogenatmosphere, were examined for hydrogen contamination by secondary-ion massspectrometry. It is found that hydrogen accumulates at the InP surface duringannealing. Annealing of Be-implanted InP leads to similar profile shapes for theBe and H atoms. Passivation of the Be acceptors, if effective at all, appears tobe of only minor significance.

  15. Rhodium catalysts bound to functionalized mesoporous silica

    SciTech Connect

    Bitterwolf, Thomas E.; Newell, J D.; Carver, Colin T.; Addleman, Raymond S.; Linehan, John C.; Fryxell, Glen E.

    2004-07-20

    Phosphine and amine functionalized mesoporous silica materials were metallated with Rh(CO)2(i-Pr2NH)Cl or Rh2(CO)4Cl2, respectively, to yield catalysts containing the Rh(PPh2R)2(CO)Cl or Rh(CO)2(NH2R)Cl, where R is a propyl chain bonded to the silica surface, reactive centers. In order to ascertain the effect of pore size on rates of hydroformylation catalysis both 35 and 45 ? pore size materials were used. Using the hydroformylation of octene as a reference reaction, the phosphine based, 45 ? catalysts were 1.5-1.3 times faster than the amine based, 45 ? materials were 2.6-2.1 times faster than the 35 ? catalysts, and the 45 ? materials. The orientation of the catalyst relative to the functionalized surface, and the steric environment around the catalyst active site appear to be significant in determining rate of reaction. The ability of the surface bound phosphine catalysts to affect hydroformylation was strongly influenced by the steric constraints of the substrate. Terminal alkenes were readily hydroformylated and norbornene was slowly hydroformylated, but pinene, trans-cyclododecene, cyclohexene and cholesterol were nonreactive to the catalytic center.

  16. Zn(II) Robson macrocycles as templates for chelating diphosphines.

    PubMed

    Ponsico, Sergio; Gulyas, Henrik; Martínez-Belmonte, Marta; Escudero-Adán, Eduardo C; Freixa, Zoraida; van Leeuwen, Piet W N M

    2011-10-28

    Chelating diphosphines were constructed using dinuclear Zn(II) complexes of Robson macrocycles (Zn-RMCs) as templates. The assembly process is driven by the interaction between the metal centers (Lewis acids) with anionic and neutral Lewis base-functionalized monophosphines. The stability of the final structure depends on the geometry and the affinity of the functional groups of the ditopic phosphines and on the structure of the RMC. In the free ligand the ditopic phosphines coordinate at opposite faces of the pseudo-planar macrocycle as is shown in the molecular structure of several of the assemblies, according to X-ray diffraction. Pre-organization of the system by coordinating the phosphorus atoms to a transition metal center enforced coordination of the functional groups at the same face of the RMC. For several templated diphosphines cis-PtCl(2) complexes were identified by NMR. The in situ assembled diphosphines showed a chelating effect in the rhodium catalyzed hydroformylation of 1-octene. Combination of Zn-RMC 3 and phosphine A gave the highest l/b ratio (13) in acetonitrile. PMID:21874185

  17. The role of ligands in the optical and electronic spectra of CdSe nanoclusters

    SciTech Connect

    Kilina, Svletana; Sergei, Ivanov A; Victor, Klimov I; Sergei, Tretiak

    2008-01-01

    We investigate the impact of ligands on morphology, electronic structure, and optical response of the Cd33Se33 cluster, which already overlapps in size with the smallest synthesized CdSe quantum dots (QDs). Our Density Functional Theory (DFT) calculations demonstrate significant surface reorganization both for the bare cluster and for the cluster capped by amine and phosphine oxide ligand models. We observe strong surface-ligand interactions leading to substantial charge redistribution and polarization effects on the surface. This effect results in the appearance of hybridized states, where the electronic density is spread over the cluster and the ligands. Neither the ligand's nor hybridized molecular orbitals appear as trap states inside or near the band gap of the QD. Instead, being optically dark, dense hybridized states from the edges of the valence and the conduction bands could open new relaxation channels for high energy photoexcitations. Comparing quantum dots passivated by different ligands, we found that hybridized states are denser in at the edge of the conduction band of the cluster ligated with phosphine oxide molecules than that with primary amines. Such a different manifestation of ligand binding may potentially lead to the faster electron relaxation in dots passivated by phosphine oxide than by amine ligands, which is in agreement with experimental data.

  18. Coinage metal complexes supported by the tri- and tetraphosphine ligands.

    PubMed

    Dau, Minh Thuy; Shakirova, Julia R; Karttunen, Antti J; Grachova, Elena V; Tunik, Sergey P; Melnikov, Alexey S; Pakkanen, Tapani A; Koshevoy, Igor O

    2014-05-01

    A series of tri- and tetranuclear phosphine complexes of d(10) metal ions supported by the polydentate ligands, bis(diphenylphosphinomethyl)phenylphosphine (PPP) and tris(diphenylphosphinomethyl)phosphine (PPPP), were synthesized. All the compounds under study, [AuM2(PPP)2](3+) (M = Au (1), Cu (2), Ag (3)), [M4(PPPP)2](4+) (M = Ag (4), Au (5)), [AuAg3(PPPP)2](4+) (6), and [Au2Cu2(PPPP)2(NCMe)4](4+) (7), were characterized crystallographically. The trinuclear clusters 1-3 contain a linear metal core, while in the isostructural tetranuclear complexes 4-6 the metal framework has a plane star-shaped arrangement. Cluster 7 adopts a structural motif that involves a digold unit bridged by two arms of the PPPP phosphines and decorated two spatially separated Cu(I) ions chelated by the remaining P donors. The NMR spectroscopic investigation in DMSO solution revealed the heterometallic clusters 2, 3, and 6 are stereochemically nonrigid and undergo reversible metal ions redistribution between several species, accompanied by their solvation-desolvation. The complexes 1-3 and 5-7 exhibit room temperature luminescence in the solid state (?em = 6-64%) in the spectral region from 450 to 563 nm. The phosphorescence observed originates from the triplet excited states, determined by the metal cluster-centered d?* ? p? transitions. PMID:24750114

  19. Redox chemistry in the phosphorus biogeochemical cycle

    PubMed Central

    Pasek, Matthew A.; Sampson, Jacqueline M.; Atlas, Zachary

    2014-01-01

    The element phosphorus (P) controls growth in many ecosystems as the limiting nutrient, where it is broadly considered to reside as pentavalent P in phosphate minerals and organic esters. Exceptions to pentavalent P include phosphine—PH3—a trace atmospheric gas, and phosphite and hypophosphite, P anions that have been detected recently in lightning strikes, eutrophic lakes, geothermal springs, and termite hindguts. Reduced oxidation state P compounds include the phosphonates, characterized by C?P bonds, which bear up to 25% of total organic dissolved phosphorus. Reduced P compounds have been considered to be rare; however, the microbial ability to use reduced P compounds as sole P sources is ubiquitous. Here we show that between 10% and 20% of dissolved P bears a redox state of less than +5 in water samples from central Florida, on average, with some samples bearing almost as much reduced P as phosphate. If the quantity of reduced P observed in the water samples from Florida studied here is broadly characteristic of similar environments on the global scale, it accounts well for the concentration of atmospheric phosphine and provides a rationale for the ubiquity of phosphite utilization genes in nature. Phosphine is generated at a quantity consistent with thermodynamic equilibrium established by the disproportionation reaction of reduced P species. Comprising 10–20% of the total dissolved P inventory in Florida environments, reduced P compounds could hence be a critical part of the phosphorus biogeochemical cycle, and in turn may impact global carbon cycling and methanogenesis. PMID:25313061

  20. Cassini/CIRS Observations of Saturn's "Storm Alley"

    NASA Technical Reports Server (NTRS)

    Hesman, Brigette E.

    2010-01-01

    In the Voyager era storms on Saturn were observed predominantly in the northern hemisphere, however, in recent years storm activity has been confined to a narrow range of latitudes referred to as "storm alley" (approx.40degS planetographic latitude). Throughout Cassini's prime mission storms have been detected by two independent instruments: ISS through dayside images and RPWS using radio emissions from Saturn Electrostatic Discharges (SED's) (Dyudina et al. 2007). Analysis of these storms indicates that the cloud tops are in the 200 - 500rnbar altitude range. During Saturn's Equinox, in August 2009, lSS imaged lightning on the night side in storm alley when ring-shine was at a minimum (Dyudina et al. 2010). This study indicates that lightning may have originated as deep as the water cloud. Decently, Cassini/CIRS was targeted at storm alley while a storm, originally detected by amateurs, was ongoing (March 2010). Phosphine can be used as a tracer of vertical transport because it is a disequilibrium species that falls off with altitude in the upper troposphere. CIRS can measure temperature and phosphine abundance independently in the altitude range where these cloud tops occur. Early analysis of these data shows stronger phosphine absorption at storm longitudes. This is an indication that powerful updrafts were dredging material upward into the upper troposphere. The results of the analysis of the March 2010 CIRS observations of storm alley will be presented.