Showing papers in "Chemistry Letters in 1986"
TL;DR: In this article, the electrochemical reduction of CO2 was studied with galvanostatic (5 mA cm−2) electrolysis at a copper electrode between 0 and 40 °C.
Abstract: The electrochemical reduction of CO2 was studied with galvanostatic (5 mA cm−2) electrolysis at a copper electrode between 0 and 40 °C. The production of CH4 and C2H4 was confirmed by GC with 4 different columns. The faradaic efficiency of CH4 formation was about 65% at 0 °C and dropped with an increase of temperature, whereas that of C2H4 formation rose to ca. 20% at 40 °C.
473 citations
TL;DR: In this paper, a generalized molecular orbital (GMO) theory for magnetically interacting organic compounds has been presented and applied to the calculations of the effective exchange integrals (Jab) for the cyclophane-type carbene dimers whose para and ortho-isomers have the high-spin ground state.
Abstract: A generalized molecular orbital (GMO) theory for magnetically interacting organic compounds has been presented. The theory is applied to the calculations of the effective exchange integrals (Jab) for the cyclophane-type carbene dimers whose para and ortho-isomers have the high-spin ground state. The calculated Jab-values are consistent with observations.
175 citations
TL;DR: The distance between two layers of the polyimide multilayer film was estimated to be 4 A. as mentioned in this paper, which is the longest known distance between any two layers in polyimides.
Abstract: Monolayer film of polyamic acid alkylamine salt at air–water interface was successfully deposited onto appropriate plates. Subsequent treatment of the multilayer film with a mixture of acetic anhydride and pyridine afforded the multilayer film of polyimide. The distance between two layers of the polyimide multilayer film was estimated to be 4 A.
128 citations
TL;DR: In this article, the electrical conductivity of alkylthio-substituted tetrathiafulvalene (TTCn-TTF) single crystal has been measured in a vacuum of 10−4 Pa with the two probe method.
Abstract: The electrical conductivity of alkylthio-substituted tetrathiafulvalene (TTCn-TTF) single crystal has been measured in a vacuum of 10−4 Pa with the two probe method. The room temperature dark condu...
120 citations
TL;DR: In this paper, the asymmetric oxidation of sulfides into the corresponding sulfoxides was achieved with organic hydroperoxides in the presence of a catalytic amount of optically active Schiff base-oxovanadium(IV) complexes.
Abstract: The asymmetric oxidation of sulfides into the corresponding sulfoxides was achieved with organic hydroperoxides in the presence of a catalytic amount of optically active Schiff base-oxovanadium(IV) complexes; in most cases the optical yields (e.e.) ranged between 20 and 40%.
104 citations
TL;DR: Optical resolution of five β-adrenergic blocking agents (β-blockers) was examined by HPLC on 13 chiral stationary phases composing of cellulose triphenyl carbamate derivatives.
Abstract: Optical resolution of five β-adrenergic blocking agents (β-blockers) alprenolol, oxyprenolol, propranolol, pindolol, and atenolol was examined by HPLC on 13 chiral stationary phases composing of cellulose triphenylcarbamate derivatives. All β-blockers were completely resolved on a cellulose tris(3,5-dimethylphenylcarbamate) column.
93 citations
TL;DR: In this article, a new molecular superconductor based on BEDT-TTF molecule was prepared electrochemically by using the mixed supporting electrolyte, (n-C4H9)4NI3 and (n − C4H8)4NAuI2.
Abstract: A new molecular superconductor based on BEDT-TTF molecule was prepared electrochemically by using the mixed supporting electrolyte, (n-C4H9)4NI3 and (n-C4H8)4NAuI2. The superconducting transition takes place at ambient pressure at 3.6 K. X-Ray diffraction patterns show that the system can be approximately assigned to a pseudo orthorhombic one with the lattice constants of a=10.076(2), b=33.853(5), c=4.964(1) A.
88 citations
TL;DR: The crystal and electronic structures of molecular superconductor θ-(BEDT-TTF)2(I3)1−x(AuI2)x (x < 0.02) were examined as discussed by the authors.
Abstract: The crystal and electronic structures of molecular superconductor θ-(BEDT-TTF)2(I3)1−x(AuI2)x (x<0.02) were examined. BEDT-TTF molecules form a two-dimensional network. The dihedral angle between the planes of the neighbouring molecules interrelated by the screw axis is about 80°. Examination of the band structure suggests that this complex is the first example of the molecular conductor with a completely round two-dimensional Fermi surface.
74 citations
TL;DR: In the presence of a catalytic amount of 2-cyclohexen-1-one, decarboxylation of α-amino acids proceeds smoothly and affords the corresponding amino compounds in good yields.
Abstract: In the presence of a catalytic amount of 2-cyclohexen-1-one, decarboxylation of α-amino acids proceeds smoothly and affords the corresponding amino compounds in good yields. Optically active amino compounds, (3R)-(−)-3-hydroxypyrrolidine and (2R)-(−)-2-hydroxypropylamine are obtained in 93% and 80% yields, respectively.
69 citations
TL;DR: In this article, thin films of polyamic acid alkylamine salts which possess long alkyl side chain were successfully prepared at the air-water interface, and it was concluded that the polymer salts had a monolayer structure in which aromatic rings of the polyamic acids lied flat on the water surface.
Abstract: Thin films of polyamic acid alkylamine salts which possess long alkyl side chain were successfully prepared at air–water interface. It was concluded that the polymer salts had a monolayer structure in which aromatic rings of the polyamic acids lied flat on the water surface.
68 citations
TL;DR: A variety of alkenes and alkynes efficiently undergo the perfluoroalkylation with F-alkyl iodides in the presence of a catalytic amount of tetrakis(triphenylphosphine)palladium(0) in hexane as mentioned in this paper.
Abstract: A variety of alkenes and alkynes efficiently undergo the perfluoroalkylation with F-alkyl iodides in the presence of a catalytic amount of tetrakis(triphenylphosphine)palladium(0) in hexane to give good yields of the corresponding F-alkylated alkyl and alkenyl iodides, respectively.
TL;DR: In this paper, stable condensed monolayers of four different amphiphilic derivatives of β-cyclodextrin were formed on a water subphase, and Langmuir-Blodgett films were obtained for three derivatives.
Abstract: Stable condensed monolayers of four different amphiphilic derivatives of β-cyclodextrin were formed on a water subphase. The base of the cylindrical cyclodextrin residue was found to be parallel to the water surface. Langmuir–Blodgett films were obtained for three derivatives.
TL;DR: The bulk conductivity of the N-docosylpyridinium-(TCNQ)2 was achieved using the amphiphilic 1:2 charge transfer complex without any doping or further treatments as mentioned in this paper.
Abstract: The bulk conductivity, 10−2 S cm−1, in the lateral direction of the Langmuir–Blodgett films has been achieved using the amphiphilic 1:2 charge transfer complex, N-docosylpyridinium-(TCNQ)2, without any doping or further treatments. These films are stable for at least two months in air at room temperature.
TL;DR: In this paper, the carboxylation of aryl halides, β-bromostyrene, and allyl acetates has been performed in an aprotic solvent saturated with carbon dioxide in the presence of a catalytic amount of PdCl2(Ph3P)2 and/or Pd(Ph 3P)4.
Abstract: Electroreductive carboxylation of aryl halides, β-bromostyrene, and allyl acetates has been performed in an aprotic solvent saturated with carbon dioxide in the presence of a catalytic amount of PdCl2(Ph3P)2 and/or Pd(Ph3P)4.
TL;DR: In this paper, the synthesis of ethylene directly from methane has been tested in the presence of oxygen over the LiCl-added transition metal oxides, and the oxides of Mn and Ni with LiCl produced ethylene with high selectivity and yield (ca. 27%) under the following experimental conditions: T=1023 K, P(CH4)/P(O2)=2/1, PCH4)=5.1 kPa, and W/F=600-1200 g l−1s.
Abstract: The synthesis of ethylene directly from methane has been tested in the presence of oxygen over the LiCl-added transition metal oxides. The oxides of Mn and Ni with LiCl produced ethylene with high selectivity (ca. 60%) and yield (ca. 27%) under the following experimental conditions: T=1023 K, P(CH4)/P(O2)=2/1, P(CH4)=5.1 kPa, and W/F=600–1200 g l−1s.
TL;DR: In this paper, a trivalent iodine reagents possessing chiral center were generated by the reaction of iodosylbenzene with the derivatives of L-tartaric anhydride.
Abstract: New trivalent iodine reagents possessing chiral center were generated by the reaction of iodosylbenzene with the derivatives of L-tartaric anhydride. The reagents cleanly oxidize prochiral sulfides to optically active sulfoxides with substantial asymmetric induction.
TL;DR: The asymmetric Diels-Alder reaction between prochiral dienes and dienophiles prepared from α,β-unsaturated acids and 1,3-oxazolidin-2-one proceeds by the use of a chiral alkoxy titanium(IV) to give the corresponding cycloadducts in high enantioselectivity as discussed by the authors.
Abstract: The asymmetric Diels–Alder reaction between prochiral dienes and dienophiles prepared from α,β-unsaturated acids and 1,3-oxazolidin-2-one proceeds by the use of a chiral alkoxy titanium(IV) to give the corresponding cycloadducts in high enantioselectivity.
TL;DR: Amines reacted with primary alcohols in the presence of a platinum complex catalyst at 120-180 °C to give N-alkylated or N-allylated compounds.
Abstract: Amines reacted with primary alcohols in the presence of a platinum complex catalyst at 120–180 °C to give N-alkylated or N-allylated compounds.
TL;DR: The stereochemical outcome of the azide displacement of triflates derived from a piperidin-3-ol depends on the protecting group on the ring nitrogen.
Abstract: The stereochemical outcome of the azide displacement of triflates derived from a piperidin-3-ol depends on the protecting group on the ring nitrogen and allows the synthesis of 2-acetamido-1,5-imino-1,2,5-trideoxy-D-glucitol (a potent and specific inhibitor of a number of β-N-acetylglucosaminidases) and of 2-acetamido-1,5-imino-1,2,5-trideoxy-D-mannitol
TL;DR: In this article, terminal olefins are oxidized to ketones in high yields under mild conditions using palladium chloride and cyclodextrins as catalysts in two-phase systems.
Abstract: Terminal olefins are oxidized to ketones in high yields under mild conditions using palladium chloride and cyclodextrins as catalysts in two-phase systems; cyclodextrins show substrate selectivity.
TL;DR: It was found that vitamin E could move in the liposomal membranes rapidly but that the antioxidant efficiency in the membranes was considerably lower than that in homogeneous solution.
Abstract: Antioxidant activity of vitamin E in liposomal membranes was compared with that in homogeneous solution. It was found that vitamin E could move in the liposomal membranes rapidly but that the antioxidant efficiency in the membranes was considerably lower than that in homogeneous solution.
TL;DR: Palladium catalyzed reactions of ternary systems involving bromobenzene, t-butyl isocyanide, and organotin compounds were found to occur giving the corresponding imines, although the catalytic efficiencies were rather low as mentioned in this paper.
Abstract: Palladium catalyzed reactions of ternary systems involving bromobenzene, t-butyl isocyanide, and organotin compounds were found to occur giving the corresponding imines, although the catalytic efficiencies were rather low.
TL;DR: In this paper, photolysis of a C6D6 solution of (η5-C5H5)Fe(CO)2SiMe2SiR2 (Fp-SiMe 2SiMeR2; R=Me, Et) results in the formation of monosilyl-Fp derivatives with the scrambling of alkyl groups.
Abstract: Photolysis of a C6D6 solution of (η5-C5H5)Fe(CO)2SiMe2SiMeR2 (Fp-SiMe2SiMeR2; R=Me, Et) results in the formation of monosilyl-Fp derivatives with the scrambling of alkyl groups. Possible reaction pathways involving silyleneiron intermediates are discussed.
TL;DR: In this article, the half-wave potential of dichloromethane was investigated with the addition of alkaline cations and showed an abrupt decrease of the binding constant of 1 with cations upon electrochemical oxidation.
Abstract: The effects of cations on the half-wave potential for oxidation of pentaoxa [13] ferrocenophane (1) in dichloromethane were studied. The shift of the half-wave potential by the addition of alkaline cations shows the abrupt decrease of the binding constant of 1 with cations upon electrochemical oxidation.
TL;DR: An L-band ESR spectrometer using a loop-gap resonator with an electric shield was constructed in order to measure large quantities of wet biological samples at in vivo state.
Abstract: An L-band ESR spectrometer using a loop-gap resonator with an electric shield was constructed in order to measure large quantities of wet biological samples at in vivo state. The principal components of the loop-gap resonator and the comparison of the sensitivity between X-band cavity and the loop-gap resonator were described.
TL;DR: The Diels-Alder reaction between prochiral dienophiles and cyclopentadiene proceeds in an enantioselective manner by the use of a catalytic amount of a chiral alkoxy titanium(IV) in the presence of Molecular Sieves 4A as mentioned in this paper.
Abstract: The Diels–Alder reaction between prochiral dienophiles and cyclopentadiene proceeds in an enantioselective manner by the use of a catalytic amount of a chiral alkoxy titanium(IV) in the presence of Molecular Sieves 4A.
TL;DR: In this article, the phthalocyanine complexes of yttrium(III) and lanthanoid (III) ions, Pc3Ln2 (Pc = phthalocalyanine anion, Ln = lanthanoidal cation) were prepared and characterized.
Abstract: Phthalocyanine complexes of yttrium(III) and lanthanoid(III) ions, Pc3Ln2 (Pc = phthalocyanine anion, Ln = lanthanoid(III) cation) were prepared and characterized. A Q band undergoes a blue shift w...
TL;DR: In this article, the authors investigated the gas sensitivity of CuO/ZnO hetero-contact at 160-340 °C and showed that the sensitivity changed not only with the kind of gases and measuring temperature but also with the voltage applied to the hetero contact.
Abstract: Gas sensitivity of CuO/ZnO hetero-contact was investigated at 160–340 °C. The gas sensitivity changed not only with the kind of gases and measuring temperature but with the voltage applied to the hetero-contact. Very high sensitivity and selectivity for CO gas was observed at 260 °C under the applied voltage of 0.1–0.9 V.
TL;DR: The crystal of β′-(BEDT-TTF)2ICl2 has a modified structure of organic superconductor, and the anisotropy of the intermolecular overlap integrals of HOMO of BEDT TTF in β′-TFT 2ICl 2 suggests the 1D character of the electronic structure as mentioned in this paper.
Abstract: The crystal of β′-(BEDT-TTF)2ICl2 has a modified structure of organic superconductor, β-(BEDT-TTF)2I3. Unlike the β-type salt with a two-dimensional(2D) electronic structure, the anisotropy of the intermolecular overlap integrals of HOMO of BEDT-TTF in β′-(BEDT-TTF )2ICl2 suggests the 1D character of the electronic structure.
TL;DR: The reaction of diisopropyl (Z)-(1-bromo-1-alkenyl)boronates readily obtainable, with organolithiums and bases takes place readily to give (E)-( 1-organo-, 1-alkENyl)borsates, the cross-coupling of which with various organic halides proceeds smoothly in the presence of Pd-catalyst and base to afford stereodefined trisubstituted alkenes in good yields.
Abstract: The reaction of diisopropyl (Z)-(1-bromo-1-alkenyl)boronates readily obtainable, with organolithiums and bases takes place readily to give (E)-(1-organo-1-alkenyl)boronates, the cross-coupling of which with various organic halides proceeds smoothly in the presence of Pd-catalyst and base to afford stereodefined trisubstituted alkenes in good yields.