Search results for "METHANE"
showing 10 items of 1763 documents
First Dibenzophospholyl(diphenylphosphino)methane−Borane Hybrid P−(η2-BH3) Ligand: Synthesis and Rhodium(I) Complex
2009
The first dibenzophospholyl(diphenylphosphino)methane−borane hybrid ligand has been prepared from a Pd-catalyzed reaction of (chloromethyl)diphenylphosphine−borane with the dibenzophospholyl anion. This borane precursor is readily synthesized using a promising new reaction of diphenylphosphine−borane with dichloromethane, under phase transfer catalysis (PTC) conditions. The dibenzophospholyl(diphenylphosphino)methane−borane acts as a chelating P−(η2-BH3) ligand to afford an air-stable Rh(I) complex. The X-ray crystal structure of this complex shows complexation of both benzophospholyl and borane moieties.
Cationic Cyclopentadienyl Phenylenediamido Titanium Species Generated by Reaction of TiCpR[1,2-C6H4(NCH2t-Bu)2]R (CpR = η5-C5H5, η5-C5Me5; R = CH3, C…
2006
The reaction of TiCpR[1,2-C6H4(NNp)2]R with the Lewis acid B(C6F5)3 in noncoordinating solvent affords the new zwitterionic species TiCpR[1,2-C6H4(NNp)2)][μ-RB(C6F5)3]. When the reaction is performed in dichloromethane, the [μ-RB(C6F5)3]- anion is displaced by solvent molecules, giving ionic products in which the anion is not coordinated. The cyclopentadienyl zwitterionic complexes TiCp[1,2-C6H4(NNp)2)[μ-RB(C6F5)3] decompose via ligand scrambling between boron and titanium to give the neutral titanium complex TiCp[1,2-C6H4(NNp)2](C6F5) along with the byproduct RB(C6F5)2. In contrast, the pentamethylcyclopentadienyl analogues TiCp*[1,2-C6H4(NNp)2][μ-RB(C6F5)3] evolve through C−H activation t…
Ligand entrapment in twofold interpenetrating PtS matrixes by metallo-organic frameworks.
2003
Single-crystal X-ray crystallography was used to determine the structures of four metallo-organic frameworks (MOFs). A dendritic tetradentate ligand (tetrakis(isonicotinoxymethyl)methane, TINM) was used with first-row transition-metal elements copper, nickel, and cobalt to synthesize MOFs with a PtS interpenetration, due to both planar and tetrahedral junctions being present in the framework. Two different polymeric complexes, 1 and 2, were obtained from similar starting materials, TINM and Cu(NO(3))(2).3H(2)O, but different solvents. The use of dichloromethane in addition to methanol and water promoted the coordination of nitrate ions to the copper. With only methanol and water used as sol…
Line broadening coefficient calculations for methane perturbed by nitrogen
2010
Abstract We report semiclassical line broadening calculations for methane perturbed by nitrogen at room temperature. For this, we have developed a symmetrized version of the Robert and Bonamy theory. The interaction potential was built from electrostatic (octopole and hexadecapole for methane, quadrupole for nitrogen) and atom–atom contributions. The relative (classical) trajectories of the molecules were computed in the frame of the usual parabolic model, through analytical formula. High orders of developments had to be used for the short range molecular interactions. As a consequence, a combination of symbolic computation and source code generation was employed to implement practical calc…
Calculated line broadening parameters for methane perturbed by diatomic molecules
2013
International audience; We report semiclassical line broadening calculations for methane perturbed by diatomic molecules: nitrogen, N2, oxygen, O2 and hydrogen, H2, at room temperature. For this, we have developed a symmetrized version of the Robert and Bonamy theory. The interaction potential was built from electrostatic (octopole and hexadecapole for methane, quadrupole for the diatomic molecules) and atom-atom contributions. The relative (classical) trajectories of the molecules were computed in the frame of the usual parabolic model, through analytical formula. High orders of developments had to be used for the short range molecular interactions in the case of N2 and O2. For H2, a lower…
End Capping Ring-Opening Olefin Metathesis Polymerization Polymers with Vinyl Lactones
2008
The selective placement of a functional group at the chain end of a ring-opening metathesis polymer using ruthenium carbene initiators has been a significant limitation. Here we demonstrate a highly effective and facile end-capping technique for ROMP with living ruthenium carbene chain ends using single-turnover olefin metathesis substrates. Vinylene carbonate and 3H-furanone are introduced as functionalization and termination agents for the ruthenium-initiated ring-opening metathesis polymerization. This leads directly to the formation of functional polymer end groups without further chemical transformation steps. Aldehyde and carboxylic acid end groups can be introduced by this new method…
Effect of some indole derivatives on xenobiotic metabolism and xenobiotic-induced toxicity in cultured rat liver slices.
1999
In this study the effect of some indole derivatives on xenobiotic metabolizing enzymes and xenobiotic-induced toxicity has been examined in cultured precision-cut liver slices from male Sprague-Dawley rats. While treatment of rat liver slices for 72 hours with 2-200 microM of either indole-3-carbinol (I3C) or indole-3-acetonitrile (3-ICN) had little effect on cytochrome P-450 (CYP)-dependent enzyme activities, enzyme induction was observed after in vivo administration of I3C. The treatment of rat liver slices with 50 microM 3,3'-diindolylmethane (DIM; a dimer derived from I3C under acidic conditions) for 72 hours resulted in a marked induction of CYP-dependent enzyme activities. DIM appears…
Drinking water disinfection by-products, genetic polymorphisms, and birth outcomes in a european mother-child cohort study
2016
Background: We examined the association between exposure during pregnancy to trihalomethanes, the most common water disinfection by-products, and birth outcomes in a European cohort study (Health Impacts of Long-Term Exposure to Disinfection By-Products in Drinking Water). We took into account exposure through different water uses, measures of water toxicity, and genetic susceptibility. Methods: We enrolled 14,005 mothers (2002-2010) and their children from France, Greece, Lithuania, Spain, and the UK. Information on lifestyle-and water-related activities was recorded. We ascertained residential concentrations of trihalomethanes through regulatory records and ad hoc sampling campaigns and e…
Modulation of induced reversion frequency by nucleotide pool imbalance as a tool for mutant characterization.
1987
Addition of thymidine (TdR) or deoxycytidine (CdR) to the culture medium during posttreatment incubation affected the frequency of mutagen-induced reversion in three hypoxanthine-guanine phosphoribosyl transferase-deficient mutants of V79 Chinese hamster cells. With two of the mutants (E20 and I3), reversions induced by N-ethylnitrosourea, ethyl methanesulfonate, and methyl methanesulfonate were enhanced by TdR and were either decreased (E20) or not affected (I3) by CdR. With the third mutant (E21), alkylating agent-induced reversions were enhanced by CdR and decreased by TdR. Finally, 6-amino-2-hydroxypurine induced reversions were enhanced by TdR in mutant I3 and were decreased by TdR or …
Drinking water disinfection by-products during pregnancy and child neuropsychological development in the INMA Spanish cohort study.
2017
Background: Disinfection by-products (DBPs) constitute a complex mixture of prevalent chemicals in drinking water and there is evidence of neurotoxicity for some of them. Objectives: We evaluated the association between estimates of DBP exposure during pregnancy and child neuropsychological outcomes at 1 and 4–5 years of age. Methods: We conducted a population-based mother-child cohort study in Spain with recruitment at first trimester of gestation (INMA Project, 2003–2008). Neuropsychological development was measured at 1 year of age using the Bayley Scales of Infant Development and at 4–5 years with the McCarthy Scales of Children's Abilities. Modeled tap water concentrations of trihalome…