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1998 Volume 9 Issue 2
1998, 9(2): 113-115
Abstract:
A D-Galactopyranoside of C60 has been synthesized and its structure has been identified by the NMR, FD-MS, FT-IR spectra, etc..
A D-Galactopyranoside of C60 has been synthesized and its structure has been identified by the NMR, FD-MS, FT-IR spectra, etc..
1998, 9(2): 117-119
Abstract:
We synthesized α-seleno substituted semistabilized arsonium ylide 3 by the transylida-tion reaction and found that it could undergo Wittig reaction smoothly as a new method for synthe-sizing vinyl selenides.
We synthesized α-seleno substituted semistabilized arsonium ylide 3 by the transylida-tion reaction and found that it could undergo Wittig reaction smoothly as a new method for synthe-sizing vinyl selenides.
1998, 9(2): 121-122
Abstract:
Aldimines are allylated with allyl bromide and tin powder in tetrahydrofuran to give homoallylamines in the presence of chlorotrimethylsilane.
Aldimines are allylated with allyl bromide and tin powder in tetrahydrofuran to give homoallylamines in the presence of chlorotrimethylsilane.
1998, 9(2): 123-124
Abstract:
The Knoevenagel condensation of acetylacetone with aldehydes catalyzed by indium trichloride was carried out at room temperature in acetonitrile to give aryl-or alkylideneacetylacetones in moderate to good yields.
The Knoevenagel condensation of acetylacetone with aldehydes catalyzed by indium trichloride was carried out at room temperature in acetonitrile to give aryl-or alkylideneacetylacetones in moderate to good yields.
1998, 9(2): 125-129
Abstract:
2-Phenylfuran-3, 4-dicarboxylic acid anhydride reacted with seven aromatic compounds, of which five gave keto acids in yields of 94%-63%. The structure of the keto acid was elucidated by reducing it to hydroxy acid and analyzing with NMR technique.
2-Phenylfuran-3, 4-dicarboxylic acid anhydride reacted with seven aromatic compounds, of which five gave keto acids in yields of 94%-63%. The structure of the keto acid was elucidated by reducing it to hydroxy acid and analyzing with NMR technique.
1998, 9(2): 131-134
Abstract:
The photoinduced intramolecular meta-cycloaddition of bichromophores la-Id gave diastereoselectively two types of adducts, 2a-2d and 3a-3d. respectively. The observed stereo-chemistry of cycloaddition was rationalized in terms of hydrogen bond effect induced by the 3-hydroxy group in the 5-phenylpent-1-ene skeleton.
The photoinduced intramolecular meta-cycloaddition of bichromophores la-Id gave diastereoselectively two types of adducts, 2a-2d and 3a-3d. respectively. The observed stereo-chemistry of cycloaddition was rationalized in terms of hydrogen bond effect induced by the 3-hydroxy group in the 5-phenylpent-1-ene skeleton.
1998, 9(2): 135-138
Abstract:
A new type of cyclodextrin dimers (2a-c) bridged with multidentate coordination units has been synthesized by treatment of 6-deoxy-6-hydroxyethylamino-p-cyclodextrm 1 with corre-sponding dibromides in the presence of base.
A new type of cyclodextrin dimers (2a-c) bridged with multidentate coordination units has been synthesized by treatment of 6-deoxy-6-hydroxyethylamino-p-cyclodextrm 1 with corre-sponding dibromides in the presence of base.
1998, 9(2): 139-142
Abstract:
A general method for the solid phase synthesis of hydro-uracils and thiouracils is de-scribed. Resino ester 2 reacts with various primary amines to give secondary amines 3, which are converted to the resino ureas (thioureas) 4 by treatment with isocyanates (isothiocyanates). Prepa-ration of the hydro-uracils and thiouracils 5 is achieved by acidic cyclization-cleavage from the resin. The synthesis is designed to be amenable for structure based library approach to photosys-tem Ⅱ D1 protein inhibitors.
A general method for the solid phase synthesis of hydro-uracils and thiouracils is de-scribed. Resino ester 2 reacts with various primary amines to give secondary amines 3, which are converted to the resino ureas (thioureas) 4 by treatment with isocyanates (isothiocyanates). Prepa-ration of the hydro-uracils and thiouracils 5 is achieved by acidic cyclization-cleavage from the resin. The synthesis is designed to be amenable for structure based library approach to photosys-tem Ⅱ D1 protein inhibitors.
1998, 9(2): 143-144
Abstract:
A new anthraquinone, Glyceroyl-1, 6, 8-trihydroxy-3-methyl-9, 10-dioxo-2-anthracene carboxylate I, was isolated from Clinopodium polycephalum. The chemical structure was deter-mined by spectroscopic methods.
A new anthraquinone, Glyceroyl-1, 6, 8-trihydroxy-3-methyl-9, 10-dioxo-2-anthracene carboxylate I, was isolated from Clinopodium polycephalum. The chemical structure was deter-mined by spectroscopic methods.
1998, 9(2): 145-148
Abstract:
A model for correlating the phase equilibria of solid-supercritical fluid systems has been developed. The feature of the model is that it can be used to estimate the size of the solvent-solute clusters and the local density of the solvent in the solvent-solute clusters.
A model for correlating the phase equilibria of solid-supercritical fluid systems has been developed. The feature of the model is that it can be used to estimate the size of the solvent-solute clusters and the local density of the solvent in the solvent-solute clusters.
1998, 9(2): 149-150
Abstract:
The Ziegler-Natta type catalytic systems composed of lanthanide compound and ethyl aluminum sesquichloride are effective to convert chloromethyl thiirane to polymer of molecular weight ca. 10, 000. The effects of rare earth element and ligand were studied.
The Ziegler-Natta type catalytic systems composed of lanthanide compound and ethyl aluminum sesquichloride are effective to convert chloromethyl thiirane to polymer of molecular weight ca. 10, 000. The effects of rare earth element and ligand were studied.
1998, 9(2): 151-155
Abstract:
The gas chromatographic separations of aromatic compounds using special mixed sta-tionary phases consisting of pp-β-CD+AgNO3, pp-β-CD+TlNO3, pp-β-CD+di-n-butly phthalate, pp-β-CD+BPBHpB liquid crystalline, and bentone-34+AgNO3 were investigated. Besides pp-β-CD+di-n-butyl phthalate, most of the separations deviated from the additivity and a synergistic effect was observed. The separation effects depend on the temperature and how mixing is accom-plished.
The gas chromatographic separations of aromatic compounds using special mixed sta-tionary phases consisting of pp-β-CD+AgNO3, pp-β-CD+TlNO3, pp-β-CD+di-n-butly phthalate, pp-β-CD+BPBHpB liquid crystalline, and bentone-34+AgNO3 were investigated. Besides pp-β-CD+di-n-butyl phthalate, most of the separations deviated from the additivity and a synergistic effect was observed. The separation effects depend on the temperature and how mixing is accom-plished.
1998, 9(2): 157-160
Abstract:
A new procedure for developing high performance enzyme electrode is described. The procedure is based on the covalently binding of horseradish peroxidase to a self-assembling monolayer on a gold electrode. An enhanced catalytic current is observed with addition of hydro-gen peroxide into phosphate buffer solution (PBS) in the presence of mediators. The electrode exhibits high sensitivity and a wide linear range to hydrogen peroxide.
A new procedure for developing high performance enzyme electrode is described. The procedure is based on the covalently binding of horseradish peroxidase to a self-assembling monolayer on a gold electrode. An enhanced catalytic current is observed with addition of hydro-gen peroxide into phosphate buffer solution (PBS) in the presence of mediators. The electrode exhibits high sensitivity and a wide linear range to hydrogen peroxide.
1998, 9(2): 161-163
Abstract:
The surface of silica gels was modified by an diethylamino group and an hydroxy group, simultaneously. The activity of the aminoacylase immobilized on such amino-hydroxy-silica gels was 316.8 U/g. By its catalysis, the conversions of tested N-acetyl-D, L-amino acids to L-amino acids were 85%.
The surface of silica gels was modified by an diethylamino group and an hydroxy group, simultaneously. The activity of the aminoacylase immobilized on such amino-hydroxy-silica gels was 316.8 U/g. By its catalysis, the conversions of tested N-acetyl-D, L-amino acids to L-amino acids were 85%.
1998, 9(2): 165-168
Abstract:
Self-assembled monolayers (SAMs) of ω-mercapto methoxy poly(ethylene glycol) (MPEG) on gold electrode were used as a means to detect dopamine. Dopamine (DA) had good response at the MPEG film electrode and ascorbic acid (AA) was repelled from the SAMs. The MPEG film is a biocompatible film; there was no adsorption of biosample and no inactivation at electrode surface when it was used to detect DA in biosamples.
Self-assembled monolayers (SAMs) of ω-mercapto methoxy poly(ethylene glycol) (MPEG) on gold electrode were used as a means to detect dopamine. Dopamine (DA) had good response at the MPEG film electrode and ascorbic acid (AA) was repelled from the SAMs. The MPEG film is a biocompatible film; there was no adsorption of biosample and no inactivation at electrode surface when it was used to detect DA in biosamples.
1998, 9(2): 169-171
Abstract:
The electrodeposition of neodymium on Pt and Cu electrodes was investigated in DMSO containing NdCl3 and a small mount of water at room temperature. Cyclic voltammetry indicated that the reduction process of Nd(Ⅲ) on the Pt cathode was complicated. The one-step reduction wave showed two steps by adding 0.3mol/L ethylenediamine(EN). A delicate yellow, lustrous, strongly adhering film on the Cu electrode was obtained using potentiostatic electrolysis at-1.80 V(vs. aq SCE).
The electrodeposition of neodymium on Pt and Cu electrodes was investigated in DMSO containing NdCl3 and a small mount of water at room temperature. Cyclic voltammetry indicated that the reduction process of Nd(Ⅲ) on the Pt cathode was complicated. The one-step reduction wave showed two steps by adding 0.3mol/L ethylenediamine(EN). A delicate yellow, lustrous, strongly adhering film on the Cu electrode was obtained using potentiostatic electrolysis at-1.80 V(vs. aq SCE).
1998, 9(2): 173-175
Abstract:
The comparison of the determination of chemical composition distributions of butadi-ene-styrene copolymers, obtained by the formula method and experimental method of GPC, is given in this paper. The relative error of average composition was shown to be less than 5%. The formula method was found to be a more convenient and time-saving approach in the characteriza-tion of the copolymer composition distribution.
The comparison of the determination of chemical composition distributions of butadi-ene-styrene copolymers, obtained by the formula method and experimental method of GPC, is given in this paper. The relative error of average composition was shown to be less than 5%. The formula method was found to be a more convenient and time-saving approach in the characteriza-tion of the copolymer composition distribution.
1998, 9(2): 177-179
Abstract:
A new approach was employed to calculate the canonical (thermal) rate constant based on unified statistical theory. All information for the calculation was obtained from ab initio methods. The flux integral for any point of reaction coordinate was calculated by counting the number of quantum states and applied to determine the dividing surfaces along the intrinsic reaction coor-dinate (IRC). The classical exchange reaction H2+H, as an example, was investigated. The IRC for the reaction has been traced and detailed information of IRC was carried out at the QCISD/6-311G** level.The calculated rate constants are well consistent with the experimental results.
A new approach was employed to calculate the canonical (thermal) rate constant based on unified statistical theory. All information for the calculation was obtained from ab initio methods. The flux integral for any point of reaction coordinate was calculated by counting the number of quantum states and applied to determine the dividing surfaces along the intrinsic reaction coor-dinate (IRC). The classical exchange reaction H2+H, as an example, was investigated. The IRC for the reaction has been traced and detailed information of IRC was carried out at the QCISD/6-311G** level.The calculated rate constants are well consistent with the experimental results.
1998, 9(2): 181-185
Abstract:
The reaction of H+SO2-HO+SO was theoretically investigated sing ab initio MO methods, and HF/TZV(d, p) level of theory was employed to locate stationary points which were then characterized by calculation of the vibrational frequencies. Energies were estimated at the optimized geometries using MP2/TZV(d, p) calculations. The results show that the calculated geometries, frequencies, and thermochemical data were in good agreement with available experi-mental values. The IRC calculations confirmed that nonplanar HSO2 and HOSO adducts should be more reasonable than those of planar conformation.
The reaction of H+SO2-HO+SO was theoretically investigated sing ab initio MO methods, and HF/TZV(d, p) level of theory was employed to locate stationary points which were then characterized by calculation of the vibrational frequencies. Energies were estimated at the optimized geometries using MP2/TZV(d, p) calculations. The results show that the calculated geometries, frequencies, and thermochemical data were in good agreement with available experi-mental values. The IRC calculations confirmed that nonplanar HSO2 and HOSO adducts should be more reasonable than those of planar conformation.
1998, 9(2): 187-189
Abstract:
AM1 and PM3 methods using the unrestricted Hartree-Fock (UHF) calculations have been applied to study the thermolysis of dicyanofuroxan. The results obtained show that the reaction proceeds to product through a two-step pathway where the second one is the rate-determining step.
AM1 and PM3 methods using the unrestricted Hartree-Fock (UHF) calculations have been applied to study the thermolysis of dicyanofuroxan. The results obtained show that the reaction proceeds to product through a two-step pathway where the second one is the rate-determining step.
1998, 9(2): 191-196
Abstract:
The keto-enol tautomerization of ethyl acetoacetate (EAA) in supercritical CO2-ethanol mixture has been investigated at 308.15 K and at different pressures using UV-Vis spectroscopy. A method for calculating the local composition about EAA has been developed based on the relationship between the equilibrium constant and dielectric property of the mixing solvent. The results indicate that the local concentration of ethanol surrounding EAA is much higher than that in the bulk.
The keto-enol tautomerization of ethyl acetoacetate (EAA) in supercritical CO2-ethanol mixture has been investigated at 308.15 K and at different pressures using UV-Vis spectroscopy. A method for calculating the local composition about EAA has been developed based on the relationship between the equilibrium constant and dielectric property of the mixing solvent. The results indicate that the local concentration of ethanol surrounding EAA is much higher than that in the bulk.
1998, 9(2): 197-201
Abstract:
The solvatochromic behavior of acetone in supercritical CO2 was investigated from 75 bar to 239 bar and at 318.15K. A clustering model is proposed to investigate the formation of solute-solvent and solute-solute clusters, based on the solvatochromic study and some reasonable assumptions. At lower pressures, there were more than one solute molecules in one cluster. At higher pressures, however, each cluster only contained one solute and the clustering of solute-solvent was dominant.
The solvatochromic behavior of acetone in supercritical CO2 was investigated from 75 bar to 239 bar and at 318.15K. A clustering model is proposed to investigate the formation of solute-solvent and solute-solute clusters, based on the solvatochromic study and some reasonable assumptions. At lower pressures, there were more than one solute molecules in one cluster. At higher pressures, however, each cluster only contained one solute and the clustering of solute-solvent was dominant.
1998, 9(2): 203-206
Abstract:
Wavelet Neural Network (WNN) was employed in a rapid calculation of the atomic electron affinities, with atomic ionization potentials and atomic electron configurations chosen as input parameters. Many unmeasured values were obtained, and the estimates appeared to be sufficiently accurate for potential applications.
Wavelet Neural Network (WNN) was employed in a rapid calculation of the atomic electron affinities, with atomic ionization potentials and atomic electron configurations chosen as input parameters. Many unmeasured values were obtained, and the estimates appeared to be sufficiently accurate for potential applications.
1998, 9(2): 207-209
Abstract:
The response of a spin coated phthalocyanine film to lppm NO2 can be increased significantly by light. This may be ascribed to the irritation of phthalocyanine molecules. This irritation decreased the energy changes of the electron transfer between NO2 and phthalocyanine.
The response of a spin coated phthalocyanine film to lppm NO2 can be increased significantly by light. This may be ascribed to the irritation of phthalocyanine molecules. This irritation decreased the energy changes of the electron transfer between NO2 and phthalocyanine.
1998, 9(2): 211-213
Abstract:
A novel silver (Ⅱ) complex AgL(ClO4)2 containing a tetraazamacrocyclic ligand has been synthesized. Its electrochemical behavior was studied by cyclic voltammetry.
A novel silver (Ⅱ) complex AgL(ClO4)2 containing a tetraazamacrocyclic ligand has been synthesized. Its electrochemical behavior was studied by cyclic voltammetry.
1998, 9(2): 215-217
Abstract:
The structure of ZnL2Cl2(L=4-methoxybenzaldehyde thiosemicarbazone) has been obtained by x-ray diffraction. The compound crystallized in space group Cc with Z=4, in a unit cell of dimensions, a=9.08909(10), b=22.1420(10), c=11.7890(10)Å; β=90.050(10)°, v=2374.6(12)Å3, Dc=1.552gcm-3. μ=1.463mm-1, R=0.0338, and Rw=0.0418. The structure contains individual ZnL2Cl2 distorted tetrahedral units in which L molecules are S-bonded as monodentate to the metal ions; chloride ions are also coordinated. The nonlinear optical properties of the zinc complex are also presented in this letter.
The structure of ZnL2Cl2(L=4-methoxybenzaldehyde thiosemicarbazone) has been obtained by x-ray diffraction. The compound crystallized in space group Cc with Z=4, in a unit cell of dimensions, a=9.08909(10), b=22.1420(10), c=11.7890(10)Å; β=90.050(10)°, v=2374.6(12)Å3, Dc=1.552gcm-3. μ=1.463mm-1, R=0.0338, and Rw=0.0418. The structure contains individual ZnL2Cl2 distorted tetrahedral units in which L molecules are S-bonded as monodentate to the metal ions; chloride ions are also coordinated. The nonlinear optical properties of the zinc complex are also presented in this letter.
1998, 9(2): 219-221
Abstract:
The complexes of 2-Alkoxycarbonylalkyltin Trichlorides with 2-Salicylideneamino-phenol have been synthesized and characterized by means of elemental analysis, IR, 1H-NMR and X-ray single crystal diffraction. The structural features of the complexes are described.
The complexes of 2-Alkoxycarbonylalkyltin Trichlorides with 2-Salicylideneamino-phenol have been synthesized and characterized by means of elemental analysis, IR, 1H-NMR and X-ray single crystal diffraction. The structural features of the complexes are described.
1998, 9(2): 223-225
Abstract:
Poly(p-diethynylbenzene) (PDEB) with improved solubility was synthesized using a novel catalyst bis(triphenylphosphine)bis(p-diethynylbenzene) nickel complex (Ni-C). A surface acoustic wave (SAW) delay line oscillator was covered by Langmuir-Blodgett (LB) films of resulting PDEB to prepare a humidity sensor, which was found to have high sensitivity and good repeatability. PDEB shows promise as a good humidity-sensitive material.
Poly(p-diethynylbenzene) (PDEB) with improved solubility was synthesized using a novel catalyst bis(triphenylphosphine)bis(p-diethynylbenzene) nickel complex (Ni-C). A surface acoustic wave (SAW) delay line oscillator was covered by Langmuir-Blodgett (LB) films of resulting PDEB to prepare a humidity sensor, which was found to have high sensitivity and good repeatability. PDEB shows promise as a good humidity-sensitive material.
