Showing papers on "Acetonitrile published in 1987"
TL;DR: In this paper, the properties of cobalt tetrakis(o-aminopheny1) porphyrin polymers are described and compared to those of polypyrin solutions in acetonitrile or methylene chloride.
Abstract: are described. Oxidations of these monomers lead to thin polymeric coatings on electrodes by coupling reactions analogous to those operative in polyaniline, polypyrrole, and polyphenol electropolymerization. The films contain from two to several hundred layers of porphyrin sites and display reductive electrochemical and electronic spectroscopic properties similar to those of monomer solutions in acetonitrile or methylene chloride. The pyrtolyl- and amino-based polymers are polycationic and thus anion exchangers, whereas the hydroxy-based polymers (at pH >8) are polyanionic. Films prepared from electropolymerization of cobalt tetrakis(o-aminopheny1)porphyrin display a split Co(III/II) wave in aqueous acid and base and are good oxygen reduction catalysts, whereas films prepared from all other cobalt porphyrin monomers display only one Co(III/II) wave and are poor catalysts.
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TL;DR: In this article, the authors present bulk physical properties, solubility properties and chromatographic properties for six room temperature liquid alkylammonium nitrate and thiocyanate salts.
114 citations
TL;DR: In this article, the authors studied the adsorption of carbon dioxide, carbon dioxide anion radical and acetonitrile using PMFTIRRAS and showed that the surface concentration of the latter species increases in the cathodic direction.
106 citations
TL;DR: The inhibitor properties of dialkylammonium tetrazolides have practical consequences for the efficiency of DNA syntheses, when in situ prepared phosphoramidites are used; the same would apply for segmented, simultaneous syntheses or syntheses where recycling is performed.
Abstract: Tetrazole catalyzed reactions of a series of phosphoramidites, 5'-O-DMTdT-3'-O-P(OR1)NR2(2) (1a-h), with 3'-O-SiButPh2-6-N-benzoyl-dA (2a) in acetonitrile solution have been studied. It is found that the coupling rate depends very much on whether tetrazole is added before or after 2a, and that dialkylammonium tetrazolide salts are inhibitors. These and other facts are evidence that the reactions are subjected to nucleophilic catalysis by tetrazole, in addition to acid catalysis. The rate variations with phosphorus substituents of 1a-h are NEt2 greater than NPri2 greater than N(CH2CH2)O greater than NMePh, and OMe greater than OCH2CH2CN greater than OCHMeCH2CN greater than OCMe2CH2CN much greater than OC6H4Cl. The inhibitor properties of dialkylammonium tetrazolides have practical consequences for the efficiency of DNA syntheses, when in situ prepared phosphoramidites are used; the same would apply for segmented, simultaneous syntheses or syntheses where recycling is performed.
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TL;DR: In this paper, the first example of a selective homogeneous-catalytic co-oligomerization between CO 2 and an unsaturated substrate which takes place under CC linkage with a 3 d -transition metal was described.
78 citations
TL;DR: This bacterium could utilize many aliphatic nitriles and amides as a sole source of nitrogen but hardly utilized malononitrile, acrylonitrile or acrylamide.
Abstract: Acrylonitrile-hydrating activity was found in various bacteria belonging to the genera Arthrobacter, Corynebacterium, Microbacterium, Nocardia, Pseudomonas and Rhodococcus. A strain, N-774, isolated by acetonitrile enrichment culture from soil showed the highest activity. Taxonomic studies indicated that strain N-774 belonged to the genus Rhodococcus. The acrylonitrile-hydrating enzyme of strain N-774 was constitutively formed in the cells. Besides acrylonitrile, many nitriles were hydrated to the corresponding amides. «-Butyronitrile, suc- cinonitrile and chloroacetonitrille served as suitable substrates. This bacterium could utilize many aliphatic nitriles and amides as a sole source of nitrogen but hardly utilized malononitrile, acrylonitrile or acrylamide. Cells having high nitrile hydratase activity (about 50units/mg of dry cells) could be easily prepared by cultivation at 30°C for 40 hr in a malt extract and yeast extract medium.
TL;DR: In this paper, a 1H NMR chemical shift of the chelate py 2-CH-NC6H4OMe-p ligand to the central metal was studied.
TL;DR: In this paper, the free energy of transfer for 21 univalent ions was determined from water to methanol, acetonitrile, dimethylsulfoxide (DMSO), pyridine, tetrahydrothiophene and liquid ammonia.
TL;DR: In this article, three macrocyclic Lewis acidic hosts containing two symmetrically disposed dichlorostanna moieties (1-3, ring sizes 18, 22, 26 atoms, respectively) have been prepared as has an acyclic di-tin model, 5,5-16,16-tetrachloro-5,16 distannadocosane (4).
TL;DR: In this paper, the first time it was possible to induce the cation-radical Diels-Alder reaction between electronrich dienes and dienophiles electrochemically, thus providing a clearer view upon the mechanism of this reaction type.
TL;DR: In this article, the functional dependence of various spectroscopic and photophysical parameters on the polar co-solvent concentration in binary solvent mixtures was studied. But the results for aniline, N,N -dimethylaniline (DMA) and some further alkyl-substituted and rigid anilines derivatives in various solvents were not analyzed.
TL;DR: In this article, the surface acidity of zirconium phosphate at different stages of dehydration and heat treatments has been studied by Fourier-transform infrared spectroscopy of adsorbed pyridine, acetonitrile and acetone and by catalytic activity in the isomerization of but-1-ene.
Abstract: The surface acidity of zirconium phosphate at different stages of dehydration and heat treatments has been studied by Fourier-transform infrared spectroscopy of adsorbed pyridine, acetonitrile and acetone and by catalytic activity in the isomerization of but-1-ene. Bronsted-acidic surface POH and P(OH)2 groups are identified [v(OH)= 3670–3660 and 3600 cm–1, respectively] whose strength increases slightly on bulk dehydration. They are thought to be responsible for the activity in but-1-ene isomerization, which also increases during condensation to pyrophosphate. Lewis-acidic sites of medium-high strength have also been found, and responsible for the formation of chemisorbed forms of pyridine (v8a= 1610 cm–1), acetonitrile [v(CN) Fermi resonance doublet at 2322 and 2295 cm–1] and acetone [v(CO) 1684 cm–1]. Surface ZrOH groups are also detected on the layered ZrP2O7 surface. The results illustrate the role of exposed planes, both parallel and perpendicular to the layered structure.
TL;DR: In this article, the formal redox potentials of 12-molybdophosphate and 12 molybdosilicate up to the twelve-electron reduction per heteropolymolybdate ion were determined by cyclic voltammetry at a glassy carbon electrode in 50% (v/v) water-organic media containing some inorganic acids.
Abstract: The formal redox potentials of 12-molybdophosphate and 12-molybdosilicate up to the twelve-electron reduction per heteropolymolybdate ion were determined by cyclic voltammetry at a glassy carbon electrode in 50% (v/v) water-organic media containing some inorganic acids. These heteropolymolybdates in the presence of 1,4-dioxane (DO) or tetrahydrofuran (THF) display five two-electron reversible cathodic waves, followed by an irreversible two-electron wave, whereas the same heteropolymolybdates in the presence of 1,2-dimethoxyethane, N,N-dimethylformamide, acetonitrile, ethanol, or acetone yield five successive redox couples of 2,2,2,4, and 2e− (electrons) each. The eight-electron reduction species of 12-heteropolymolybdates are stabilized by cyclic ethers such as DO or THF. The stabilization of the eight-electron reduction species by the addition of a cyclic ether has been explained by taking into account the adduct formation between the molecules of the cyclic ether and 12-heteropolymolybdate.
TL;DR: Palladium, platinum, cobalt, and rhodium triphenylphosphine complexes were found to catalyze the formation of acid fluorides via carbonylation of organic halides with fluoride salts as discussed by the authors.
TL;DR: In this paper, the gas phase ion/molecule reactions of the atomic oxygen anion with a series of substituted methanes have been examined using the flowing afterglow technique.
TL;DR: La reduction de [Ru(MeCN) 3 (triars)](CF 3 SO 3 ) 2 (Triars=MeC(CH 2 AsPh 2 ) 3 ) dans le methanol donne [RuH(NH 2 CH 2 Me) 2 (triARS)] (CF 3SO 3 ). Formation d'un complexe intermediaire metal-imine dans la reduction as discussed by the authors.
Abstract: La reduction de [Ru(MeCN) 3 (triars)](CF 3 SO 3 ) 2 (triars=MeC(CH 2 AsPh 2 ) 3 ) dans le methanol donne [RuH(NH 2 CH 2 Me) 2 (triars)](CF 3 SO 3 ). Formation d'un complexe intermediaire metal-imine dans la reduction
TL;DR: In this paper, carboxy-substituted ferrocene compounds are prepared and investigated by cyclic voltammetry in acetonitrile solution, and the half-wave potentials of most of the acids studied (E1/2=0.58 V versus s.c.
Abstract: Several carboxy-substituted ferrocene compounds are prepared and investigated by cyclic voltammetry in acetonitrile solution. The half-wave potentials of most of the acids studied (E
1/2=0.34−0.58 V versus s.c.e.) are more positive than that of ferrocene (0.33 V), reflecting a diminished susceptibility to oxidation of these compounds relative to the parent metallocene. Only β-ferrocenylpropionic acid (0.325 V) is effectively identical with the latter in its oxidation behaviour, and γ-ferrocenylbutyric acid (0.31 V) tends to be more readily oxidized. The results are of interest for subsequent chemical oxidation studies of ferrocenylcarboxylic acids.
TL;DR: Treatment of thioacetals with HgF2 in anhydrous acetonitrile, followed by oxidation with MCPBA results in the formation of α-fluorosulfoxides, which can be pyrolyzed to give vinyl fluorides as discussed by the authors.
TL;DR: The oxidative coupling of uracil derivatives t with olefins, such as methyl acrylate, acrylonitrile, methyl vinyl ketone, and styrene, using one equivalent of palladium acetate leads to the corresponding 5-(1-alkenyl)uracil derivative 2 as discussed by the authors.
Abstract: The oxidative coupling of uracil derivatives t with olefins, such as methyl acrylate, acrylonitrile, methyl vinyl ketone, and styrene, using one equivalent of palladium acetate leads to the corresponding 5-(1-alkenyl)uracil derivatives 2.
TL;DR: In this paper, the authors determined the interaction behavior of peptides with hydrophobic stationary phases on analytical columns using isnocratic or shallow gradient elution for the purpose of developing procedures for rapid optimization of conditions for preparative reversed-phase chromatography.
Abstract: We have determined the interaction behaviour of peptides with hydrophobic stationary phases on analytical columns using isnocratic or shallow gradient elution for the purpose of developing procedures for rapid optimization of conditions for preparative reversed-phase chromatography of peptides. From our investigation of the separation of two closely related decapeptides (differing by one methyl group), in a 1:1 molar ratio on an analytical C8 column, we have found that shallow gradients of 0.1% acetonitrile/min appeared to be the best compromise between resolution and a practical run time for preparative peptide separations. Up to 20mg of the two-peptide mixture was efficiently resolved on the analytical column, with >97% recovery of homogeneous peptides.