Showing papers in "Chemistry Letters in 1988"
TL;DR: An ambient pressure superconductivity of (BEDT-TTF)2Cu(SCN)2 was observed by d.c. magnetic susceptibility and electrical conductivity measurements as discussed by the authors.
Abstract: An ambient pressure superconductivity of (BEDT-TTF)2Cu(SCN)2 was observed by d.c. magnetic susceptibility and electrical conductivity measurements. The superconducting critical temperature is the highest (TC=10.4 K) among the organic superconductors so far obtained, even though the anion has a positional disorder in the crystal.
412 citations
TL;DR: In this paper, the oxygen semipermeability of CoO3-based perovskite-type oxides was investigated by partial substitution of A site and B site cations, Ba and Cu being the most effective substituents, respectively.
Abstract: Oxygen semipermeability of LnCoO3-based perovskite-type oxides changed drastically by the partial substitution of A site and B site cations, Ba and Cu being the most effective substituents, respectively. Host rare earth cations (Ln) also affected the oxygen semipermeability, which increased with a decrease in ionic radius of Ln.
296 citations
TL;DR: The crystal structures of an organic superconductor (BEDT-TTF)2Cu(NCS)2 (Tc=10.4 K) at 298 K and 104 K are determined by X-ray analysis as mentioned in this paper.
Abstract: The crystal structures of an organic superconductor (BEDT-TTF)2Cu(NCS)2 (Tc=10.4 K) at 298 K and 104 K are determined by X-ray analysis. The packing pattern of donors is nearly analogous to κ-(BEDT-TTF)2I3. The counter anion, Cu(NCS)2−, has no positional disorder and constructs a peculiar sheet where a copper ion is coordinated with a sulfur and two nitrogen atoms to form a one-dimensional polymer with a permanent dipole moment.
135 citations
TL;DR: Palladium was deposited on a porous glass tube using a technique of electroless-plating as discussed by the authors, which exhibited a remarkable permeability to hydrogen and selectively separated hydrogen from H2-N2 and H2−CO gas mixtures through the composite membrane.
Abstract: Palladium was deposited on a porous-glass tube using a technique of electroless-plating. This composite membrane exhibited a remarkable permeability to hydrogen. Moreover, hydrogen was selectively separated from H2–N2 and H2–CO gas mixtures through the composite membrane.
124 citations
TL;DR: Phenol was obtained from benzene and dinitrogen monoxide over H-ZSM-5 zeolite at 603 K, a phenol yield on a benzene basis being 8.1% at partial pressures of benzene.
Abstract: Phenol was obtained from benzene and dinitrogen monoxide over H-ZSM-5 zeolite at 603 K, a phenol yield on a benzene basis being 8.1% at partial pressures of benzene and dinitrogen monoxide of 6.9 k...
107 citations
TL;DR: In this article, a mixed-ligand β-diketonato ruthenium(III) is treated in this way, the more electron-donating ligand is preferentially displaced by two acetonitrile molecules.
Abstract: Diacetonitrilebis(β-diketonato)ruthenium(II) complexes were readily prepared by reducing the corresponding tris(β-diketonato)ruthenium(III) with zinc amalgam in an acetonitril–ethanol–water mixture. When a mixed-ligand β-diketonato complex [RuL2L′] is treated in this way, the more electron-donating ligand is preferentially displaced by two acetonitrile molecules. The diacetonitrile complexes are useful intermediates for the synthesis of mixed-ligand β-diketonato ruthenium( III) complexes of the type [RuL2L″].
98 citations
TL;DR: In this article, the size of colloidal CdS particles in aqueous medium was controlled by adding thiols in the procedure of the preparation, and the change in optical absorption spectra and the quantum yield of photoinduced electron transfer were measured for these size-controlled CcS colloids.
Abstract: Size of colloidal CdS particles in aqueous medium was controlled by adding thiols in the procedure of the preparation. The change in optical absorption spectra and the quantum yield of photoinduced electron transfer were measured for these size-controlled CdS colloids.
72 citations
TL;DR: A variety of racemic carboxylic acids have been directly resolved by normal-phase, high-performance liquid chromatography using a hexane-2-propanol eluting system as discussed by the authors.
Abstract: A variety of racemic carboxylic acids have been for the first time directly resolved by normal-phase, high-performance liquid chromatography using a hexane-2-propanol eluting system containing a small amount (≈1%) of a strong carboxylic acid, like formic acid, trichloroacetic acid, and trifluoroacetic acid.
71 citations
TL;DR: In this article, a catalytic amount of ruthenium trichloride hydrate combined with tributylphosphite at 180 °C was used to give the corresponding N-methylaminoarenes in high yields.
Abstract: Methanol reacts with aminoarenes in the presence of a catalytic amount of ruthenium trichloride hydrate combined with tributylphosphite at 180 °C to give the corresponding N-methylaminoarenes in high yields.
67 citations
TL;DR: Poly(2,5-pyridinediyl) was prepared by dehalogenation polycondensation of 2,5dibromopyridine with Ni(0)-complexes.
Abstract: Poly(2,5-pyridinediyl) was prepared by dehalogenation polycondensation of 2,5-dibromopyridine with Ni(0)-complexes. The polymer was soluble in formic acid, and the solution showed λmax at about 370 nm and large degree of depolarization.
58 citations
TL;DR: In this paper, the pH dependencies in the adsorption of various metal ions on a resin prepared by crosslinking copper(II)-complexed chitosan were investigated.
Abstract: The pH dependencies in the adsorption of various metal ions on a resin prepared by crosslinking copper(II)-complexed chitosan were investigated. Separations of gallium and indium from zinc, ferric iron and aluminum from zinc, and nickel from cobalt were possible with high selectivity by this resin. Some applications to hydrometallurgical processes are also proposed.
TL;DR: In this paper, the quantum yields of photoreactions of furylfulgides having Me, Et, n-Pr, or i-Pr on the furylalkylidene moiety were measured.
Abstract: Quantum yields of photoreactions of furylfulgides having Me, Et, n-Pr, or i-Pr on the furylalkylidene moiety were measured. The E–Z isomerization was greatly suppressed and the cyclization was accelerated when the alkyl group (R) became bulkier. When R was i-Pr, no E–Z isomerization was observed and the quantum yield of the colorizing cyclization was 0.62.
TL;DR: In this article, a carbon tetrachloride molecule is accommodated in the cavity formed in the three-dimensional framework of cadmium cyanide to give the title clathrate compound.
Abstract: Carbon tetrachloride molecule is accommodated in the cavity formed in the three-dimensional framework of cadmium cyanide to give the title clathrate compound. The cavity has a shape of adamantane-like cage edged with –Cd–CN–Cd– linkage where the Cd atom takes a tetrahedral configuration.
TL;DR: By using polyallylamine (PAA) for the aqueous subphase, the pure LB films of an azobenzene derivative with a long alkyl-chain showed reversible cis-trans photoisomerization due to the relatively large cross section of the molecule determined by the surface density of the ammonium cations of protonated PAA as mentioned in this paper.
Abstract: By using polyallylamine (PAA) for the aqueous subphase, the pure LB films of an azobenzene derivative with a long alkyl-chain showed reversible cis–trans photoisomerization due to the relatively large cross section of the molecule determined by the surface density of the ammonium cations of protonated PAA.
TL;DR: A solvent polymeric membrane ion-selective electrode based on thiocyanato(α, β, γ, δ-tetraphenylporphynate)cobalt(III) was developed in this article.
Abstract: A solvent polymeric membrane ion-selective electrode based on thiocyanato(α, β, γ, δ-tetraphenylporphynate)cobalt(III) was developed. The electrode membrane exhibits SCN−>>I−>NO2−>>C1O4−>HCO3−>HPO42−>Cl−≅Br−>NO3−≅SO42− selectivity sequence with a preference for SCN− over ClO4− by 102.5–103.1. Response of the electrode is linear in the 10−5 to 10−1 M concentration range for SCN with a slope of −49±2 mV/log a.
TL;DR: Azobenzenes in the host-guest Langmuir-Blodgett films prepared with amphiphilic β-cyclodextrin and azobenzene derivatives showed a photochromic behavior with complete reversibility as discussed by the authors.
Abstract: Azobenzenes in the host–guest Langmuir–Blodgett films prepared with amphiphilic β-cyclodextrin and azobenzene derivatives showed a photochromic behavior with complete reversibility owing to the free volume of cyclodextrin cavity, whereas the trans-to-cis isomerization was restricted in the case of the pure LB film prepared with long-chain azobenzene derivative alone Thermal cis-to-trans isomerizations in the LB films were also studied
TL;DR: In this paper, the use of water-permeable membranes for pervaporation in the esterification of carboxylic acid with ethanol was studied, and the perfect conversion due to the equilibrium shift was obtained by using an asymmetric polyetherimide membrane for removal of water generated by the Esterification.
Abstract: The use of water-permeable membranes for pervaporation in the esterification of carboxylic acid with ethanol was studied. The perfect conversion due to the equilibrium shift was obtained by using an asymmetric polyetherimide membrane for removal of water generated by the esterification.
TL;DR: In this article, the authors give a clear explanation to the "lost activity" of highly dispersed platinum catalysts caused by the so-called crystallite size effect and demonstrate the completeness of this explanation.
Abstract: The purpose of this paper is to give a clear explanation to the “lost activity” of highly dispersed platinum catalysts caused by the so-called crystallite size effect and to demonstrate the complet...
TL;DR: The enantioselective reduction of ω-hydroxy-β-ketoalkyl sulfones with bakers yeast gives (S)-ω,β-dihydroxyalkyl phenyl sulfone, which are convenient precursors for optically active lactones as shown in the synthesis of (R)-4-hexanolide and (R)umbelactone as mentioned in this paper.
Abstract: The enantioselective reduction of ω-hydroxy-β-ketoalkyl phenyl sulfones with bakers’ yeast gives (S)-ω,β-dihydroxyalkyl phenyl sulfones, which are convenient precursors for optically active lactones as shown in the synthesis of (R)-4-hexanolide and (R)-umbelactone.
TL;DR: A phospha-indane derivative was obtained via intramolecular C-H insertion of the phosphinidene generated as an intermediate by the photolysis of E-1,2-bis(2,4,6-tri-t-butylphenyl)diphosphene as mentioned in this paper.
Abstract: A phospha-indane derivative was obtained via intramolecular C–H insertion of the phosphinidene generated as an intermediate by the photolysis of E-1,2-bis(2,4,6-tri-t-butylphenyl)diphosphene whereas the photolysis through a Pyrex filter at −40 °C gave an equilibrium mixture of E and Z.
TL;DR: In this article, gas-diffusion type carbon electrodes loaded with perovskite-type oxides La1−xCaxMO3 (M=Co,Mn) were examined in 30 wt% KOH at 25 °C.
Abstract: Oxygen reduction performances of gas-diffusion type carbon electrodes loaded with perovskite-type oxides La1−xCaxMO3 (M=Co,Mn) were examined in 30 wt% KOH at 25 °C. The highest electrode performance, i.e., 2600 mA/cm2 at −125 mV vs. Hg/HgO, was obtained with large surface area La0.6Ca0.4CoO3 prepared by an amorphous precursor method.
TL;DR: In this paper, high-resolution solid-state 1H and 31P NMR revealed that there were at least three different states for protons of H3PW12O40·nH2O; protons present in highly hydrated samples, and protonated wa...
Abstract: High-resolution solid-state 1H and 31P NMR revealed that there were at least three different states for protons of H3PW12O40·nH2O; (i) protons present in highly hydrated samples, (ii) protonated wa...
TL;DR: In this paper, the authors found that the decomposition of NO is facilitated by the redox cycle of Cu, and that Y-Ba-Cu-O mixed oxide catalysts supported on MgO were found to have higher catalytic activity for NO decomposition than a commercial Pt supported catalyst at 800 °C.
Abstract: Y–Ba–Cu–O mixed oxide catalysts supported on MgO were found to have higher catalytic activity for NO decomposition than a commercial Pt supported catalyst at 800 °C. XPS analysis suggests that the decomposition of NO is facilitated by the redox cycle of Cu.
TL;DR: In this paper, a carbon electrode coating poly(acrylic acid) immobilized covalently with 2,2,6,6-tetramethylpiperydinyl-1oxy was characterized electrochemically and a similar modified carbon felt electrode was utilized successfully to electrocatalytic oxidation of nerol.
Abstract: Glassy carbon electrode coating poly(acrylic acid) immobilized covalently with 2,2,6,6-tetramethylpiperydinyl-1-oxy was characterized electrochemically and a similar modified carbon felt electrode was utilized successfully to electrocatalytic oxidation of nerol.
TL;DR: Olefins and dihydrogen were catalytically formed from alkanes at an ambient temperature in the presence of RhCl (CO)(PMe3)2 under irradiation as discussed by the authors.
Abstract: Olefins and dihydrogen were catalytically formed from alkanes at an ambient temperature in the presence of RhCl (CO)(PMe3)2 under irradiation.
TL;DR: Rhodium complexes (RhClL3, RhCl(CO)L2, [RhCl(COD)]2; L=PPh3) catalyze hydrostannation of terminal acetylenes (RC≡CH; R=Ph, Me3Si, R1OC(R2)(R3), and R1OCH2CH2; R1=THP, OAc; R 1, R2=H, Me) with Bu3SnH to produce R(Bu3Sn)C=CH2 selectively.
Abstract: Rhodium complexes (RhClL3, RhCl(CO)L2, [RhCl(COD)]2; L=PPh3) catalyze hydrostannation of terminal acetylenes (RC≡CH; R=Ph, Me3Si, R1OC(R2)(R3), and R1OCH2CH2; R1=THP, OAc; R1, R2=H, Me) with Bu3SnH to produce R(Bu3Sn)C=CH2 selectively. Other transition metal complexes [MCl2L2(M=Ni, Pd, Pt, Co)] are also active for the hydrostannation, but with less selectivity.
TL;DR: In this paper, the title compounds were used as a chiral shift reagent in 1H NMR spectroscopy to determine enantiomeric purity of amines, alcohols, sulfoxides, selenoxides and phosphine oxides, phosphinates, and arsenoxides.
Abstract: The title compounds were found to be useful as a chiral shift reagent in 1H NMR spectroscopy to determine enantiomeric purity of amines, alcohols, sulfoxides, selenoxides, phosphine oxides, phosphinates, and arsenoxides. It is also reported that the induced chemical shift difference increases when the title compound is used together with the typical chiral shift reagent, Eu(hfc)3.
TL;DR: In this paper, a 1 thin film was prepared on an indium tin oxide (ITO) electrode by the controlledpotential electrolysis of this solution, which consisted of rod-like crystals of 500 nm in length.
Abstract: Phthalocyanine (1) was dissolved to the micellar solution formed by non-ionic surfactants with ferrocenyl moiety. A 1 thin film was prepared on an indium tin oxide (ITO) electrode by the controlled-potential electrolysis of this solution. This film consisted of rod-like crystals of 500 nm in length.
TL;DR: In this article, E-2-Chloro-1-(2,4,6-tri-t-butylphenyl)-1-phospha-acetylene was allowed to react with t-butyllithium as a base to give 2-(2.4, 6, tri-t,t,butyl phenyl)-acetylene, suggesting the generation of a phosphorus analogue of isonitrile.
Abstract: E-2-Chloro-1-(2,4,6-tri-t-butylphenyl)-1-phospha-ethylene was allowed to react with t-butyllithium as a base to give 2-(2,4,6-tri-t-butylphenyl)-1-phospha-acetylene, suggesting the generation of a phosphorus analogue of isonitrile followed by migration of the phenyl group from phosphorus to carbon.
TL;DR: In this paper, direct α-iodination of some ketones using iodine-cerium(IV) ammonium nitrate in acetic acid or methanol, gave the corresponding α-IODOKetone in high yield.
Abstract: Direct α-iodination of some ketones using iodine–cerium(IV) ammonium nitrate in acetic acid or methanol, gave the corresponding α-iodoketone in high yield. In the case of 2-pentanone, 4-methyl-2-pentanone, 2-hexanone, and 2-heptanone in methanol, the regioselective products were obtained.