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1992 Volume 3 Issue 2
1992, 3(2): 79-82
Abstract:
Methyl-and Ethyl-vinyl sulfoxides (MVSO and EVSO) were first synthesized from common organic reagents, i.e. sulfate, thiourea and ethylene oxide in excellent yields. A new facile method for oxidation of vinyl sulfides to corresponing vinyl sulfoxides was developed. Application of those vinyl sulfoxides for synthetic gas separation membranes was acheived and that showed the high permselectivities to SO2, N2 and SO2/N2 mixture gases.
Methyl-and Ethyl-vinyl sulfoxides (MVSO and EVSO) were first synthesized from common organic reagents, i.e. sulfate, thiourea and ethylene oxide in excellent yields. A new facile method for oxidation of vinyl sulfides to corresponing vinyl sulfoxides was developed. Application of those vinyl sulfoxides for synthetic gas separation membranes was acheived and that showed the high permselectivities to SO2, N2 and SO2/N2 mixture gases.
1992, 3(2): 83-86
Abstract:
Relative reactivities of polyhalofluoroalkanes toward bromophilic or chlorophilic attacks have been evaluated for the first time by comparing the rates of halophilic attacks by a carbanion derived from the addition of a nucleophile to an olefin with the rate of β-elimination of the same carbanion intermediate. Relative reactivity orders of some polybromofluoroalkanes and polychlorofluoroalkanes are CF2Br2 > CF3CFBr2~CF2BrCF2Br > CF3CBr3, and CCl4 > CF3CCl3 > CF2ClCCl3 > CFCl3 > CFCl2CFCl2~CF2ClCFCl2. Early transition states for halophilic attacks are speculated.
Relative reactivities of polyhalofluoroalkanes toward bromophilic or chlorophilic attacks have been evaluated for the first time by comparing the rates of halophilic attacks by a carbanion derived from the addition of a nucleophile to an olefin with the rate of β-elimination of the same carbanion intermediate. Relative reactivity orders of some polybromofluoroalkanes and polychlorofluoroalkanes are CF2Br2 > CF3CFBr2~CF2BrCF2Br > CF3CBr3, and CCl4 > CF3CCl3 > CF2ClCCl3 > CFCl3 > CFCl2CFCl2~CF2ClCFCl2. Early transition states for halophilic attacks are speculated.
1992, 3(2): 87-90
Abstract:
High nucleophilicity of formate toward polyhalofluoroalkenes under acidic condition is described. This reaction offers a convenient method for the synthesis of E-α,β-unsaturated polyhalofluorocarboxylic acids.
High nucleophilicity of formate toward polyhalofluoroalkenes under acidic condition is described. This reaction offers a convenient method for the synthesis of E-α,β-unsaturated polyhalofluorocarboxylic acids.
1992, 3(2): 91-92
Abstract:
The stereoselective total synthesis of (S)-(+)-γ-curcumene starting from p-bromo-phenylmethyl ether via an asymmetric Grignard cross-coupling reaction in 45%ee optical yield was described.
The stereoselective total synthesis of (S)-(+)-γ-curcumene starting from p-bromo-phenylmethyl ether via an asymmetric Grignard cross-coupling reaction in 45%ee optical yield was described.
1992, 3(2): 93-94
Abstract:
Complexes of CuⅡ, NiⅡ, CoⅡ, ZnⅡ, FeⅢ, CrⅢ, CdⅡ and MnⅡ with the natural product 5-hydroxy-7,4'-dimethoxyflavone (1) have been prepared and their probable structures were proposed on the basis of elemental analyses, thermal analyses and IR and UV spectral data. The ligand and all the complexes were tested in vitro for their antibacterial activity.
Complexes of CuⅡ, NiⅡ, CoⅡ, ZnⅡ, FeⅢ, CrⅢ, CdⅡ and MnⅡ with the natural product 5-hydroxy-7,4'-dimethoxyflavone (1) have been prepared and their probable structures were proposed on the basis of elemental analyses, thermal analyses and IR and UV spectral data. The ligand and all the complexes were tested in vitro for their antibacterial activity.
1992, 3(2): 95-96
Abstract:
PLE (pig liver esterase) catalyzed hydrolysis of the title compounds demonstrated that the α-carbon with S configuration hydrolyzed faster than the R configuration and α-carbon controlled the stereoselectivity. The preliminary results showed that the highest ee obtained were only 40-48%.
PLE (pig liver esterase) catalyzed hydrolysis of the title compounds demonstrated that the α-carbon with S configuration hydrolyzed faster than the R configuration and α-carbon controlled the stereoselectivity. The preliminary results showed that the highest ee obtained were only 40-48%.
1992, 3(2): 97-98
Abstract:
The electrocarboxylation of benzyl chloride with CO2 catalyzed by metalloporphyrins and the effects of different kinds of central metals and ligands on catalytic activities are reported. These metalloporphyrins whose central metals can form corresponding M (Ⅰ) complexes such as CoTPP, FeTPP have high activities. With water-soluble porphyrin ligands such as TPPS, TTMAPI, the corresponding metalloporphyrins have high catalytic activity. Electron-with-drawing groups on the porphyrin ring cause the lowering of activity.
The electrocarboxylation of benzyl chloride with CO2 catalyzed by metalloporphyrins and the effects of different kinds of central metals and ligands on catalytic activities are reported. These metalloporphyrins whose central metals can form corresponding M (Ⅰ) complexes such as CoTPP, FeTPP have high activities. With water-soluble porphyrin ligands such as TPPS, TTMAPI, the corresponding metalloporphyrins have high catalytic activity. Electron-with-drawing groups on the porphyrin ring cause the lowering of activity.
1992, 3(2): 99-102
Abstract:
The electronic structures of polymethineimine (PMI), polyazine (PAZ) and polyazoethene(PAE) are studied on the basis of the tight-binding LCAO-8CF-CO calculations under the CNDO/2 approximations. Our result indicates that they are all poor candidates for new electric conducting materials as alternatives to polyacetylene (PA), and this is discussed in terms of the electronic structures.
PMI end PAZ have been synthesized successfully (1,2), and some of their properties have been investigated. In this article we intend to explain why and how degree of conjugation effects on their intrinsic electric conductivities by studying their electronic structures on the basis of the tight-binding LCAO-SCF-CO calculations including all valence atomic orbitals(AO'S) with complete neglect of differential overlap(CNDO/2) approximations(3,4).
The electronic structures of polymethineimine (PMI), polyazine (PAZ) and polyazoethene(PAE) are studied on the basis of the tight-binding LCAO-8CF-CO calculations under the CNDO/2 approximations. Our result indicates that they are all poor candidates for new electric conducting materials as alternatives to polyacetylene (PA), and this is discussed in terms of the electronic structures.
PMI end PAZ have been synthesized successfully (1,2), and some of their properties have been investigated. In this article we intend to explain why and how degree of conjugation effects on their intrinsic electric conductivities by studying their electronic structures on the basis of the tight-binding LCAO-SCF-CO calculations including all valence atomic orbitals(AO'S) with complete neglect of differential overlap(CNDO/2) approximations(3,4).
1992, 3(2): 103-106
Abstract:
It is found that acetoacetanilide possesses very high promoting reactivity towards ceric ion in initiating polymerization of vinyl monomer. The kinetics of acrylamide polymerization and the activation energies were studied. The initiation mechanism of ceric/acetoacetanilide is proposed on the basis of experimental results of FT-IR and ESR.
It is found that acetoacetanilide possesses very high promoting reactivity towards ceric ion in initiating polymerization of vinyl monomer. The kinetics of acrylamide polymerization and the activation energies were studied. The initiation mechanism of ceric/acetoacetanilide is proposed on the basis of experimental results of FT-IR and ESR.
1992, 3(2): 107-108
Abstract:
The dissociation constants of the reagents were determined spectrophotometrically, the existential patterns of PAR in aqueousalcohol solution were studied by quantumchemical method, and the color reactions between these reagents and Nickel (Ⅱ) were investigated.
The dissociation constants of the reagents were determined spectrophotometrically, the existential patterns of PAR in aqueousalcohol solution were studied by quantumchemical method, and the color reactions between these reagents and Nickel (Ⅱ) were investigated.
1992, 3(2): 109-110
Abstract:
Application of microwave irradiation to the syhthesis of some alkali metal metavanadates in a fraction of time required by the conventional synthetic method (2min for LiVO3, 3.5min for NaVO3) is described.
Application of microwave irradiation to the syhthesis of some alkali metal metavanadates in a fraction of time required by the conventional synthetic method (2min for LiVO3, 3.5min for NaVO3) is described.
1992, 3(2): 111-112
Abstract:
A novel gallotannin, crenulatin (1), was isolated from the stem of Rhodiola crenulata, and its structure was determined by means of spectral analyses(including 1H-1H COSY, 1H-13C COSY and 1H-13C COLOC spectral measurements)and chemical evidence.
A novel gallotannin, crenulatin (1), was isolated from the stem of Rhodiola crenulata, and its structure was determined by means of spectral analyses(including 1H-1H COSY, 1H-13C COSY and 1H-13C COLOC spectral measurements)and chemical evidence.
1992, 3(2): 113-116
Abstract:
Six new diterpene-quinones were isolated from the ethanol extract of the roots of Tripterygium regelii Sprague and their structures were elucidated through interpretation of their spectroscopic data and chemical correlations. The absolute configuration of triptoquinonoic acid A (1) was determined by X-ray crystallography.
Six new diterpene-quinones were isolated from the ethanol extract of the roots of Tripterygium regelii Sprague and their structures were elucidated through interpretation of their spectroscopic data and chemical correlations. The absolute configuration of triptoquinonoic acid A (1) was determined by X-ray crystallography.
1992, 3(2): 117-118
Abstract:
The chemical investigation of the aerial parts of Artemisia argyi gave α and β-amyrin, friedelin and a new cycloartane derivative whose structure was established, on the basis of its spectral and chemical evidences, as 3β-methoxy-9β, 19-cyclolanost-23(E)-en-25, 26-diol (1).
The chemical investigation of the aerial parts of Artemisia argyi gave α and β-amyrin, friedelin and a new cycloartane derivative whose structure was established, on the basis of its spectral and chemical evidences, as 3β-methoxy-9β, 19-cyclolanost-23(E)-en-25, 26-diol (1).
1992, 3(2): 119-120
Abstract:
The structure of a new macrocyclic compound, clemochinenoside A obtained from Clematis chinensis was identified by NMR, FAB-MS, NOE and chemical hydrolysis.
The structure of a new macrocyclic compound, clemochinenoside A obtained from Clematis chinensis was identified by NMR, FAB-MS, NOE and chemical hydrolysis.
1992, 3(2): 121-122
Abstract:
A novel neolignan, biondinin A, was isolated from the flower buds of Magnolia biondii Pamp. The structure was established as 3,3',4'-trimethoxy-4,9'-dihydroxy-6.8',9-O-7'-neolignan. It is the first reported neolignan possessing the skeleton of benzo-oxa-cyclooctane.
A novel neolignan, biondinin A, was isolated from the flower buds of Magnolia biondii Pamp. The structure was established as 3,3',4'-trimethoxy-4,9'-dihydroxy-6.8',9-O-7'-neolignan. It is the first reported neolignan possessing the skeleton of benzo-oxa-cyclooctane.
1992, 3(2): 123-126
Abstract:
Infrared spectra of bis (β-diketonato) copper (Ⅱ) complex liquid crystals with different flexible chain lengths (the carbon number=12 and 14) have been studied as a function of temperature. Conformational changes in mesogenic cores of the molecules have been characterized by using the out-of-plane bending vibration mode of aromatic C-H bonds. The result shows that for the phenylene rings and the chelate rings of the molecules there occurred an enhancement of extended conjugation of the two π-electron systems during phase transitions, which was also supported by UV measurements. It suggests that the big quasi-planar core structure in the discotic complex consisted of four phenylene rings and the central chelate rings is not maintained in every phase.
Infrared spectra of bis (β-diketonato) copper (Ⅱ) complex liquid crystals with different flexible chain lengths (the carbon number=12 and 14) have been studied as a function of temperature. Conformational changes in mesogenic cores of the molecules have been characterized by using the out-of-plane bending vibration mode of aromatic C-H bonds. The result shows that for the phenylene rings and the chelate rings of the molecules there occurred an enhancement of extended conjugation of the two π-electron systems during phase transitions, which was also supported by UV measurements. It suggests that the big quasi-planar core structure in the discotic complex consisted of four phenylene rings and the central chelate rings is not maintained in every phase.
1992, 3(2): 127-128
Abstract:
The effect of solvent on surface enhanced Raman scattering (SERS) of colloidal silver has been studied. Experiments show that the intensity of SERS is related to the polarity and molecular constitution of the solvent. The influence of solvent is due to the change of the adsorption quantity and adsorption intensity.
The effect of solvent on surface enhanced Raman scattering (SERS) of colloidal silver has been studied. Experiments show that the intensity of SERS is related to the polarity and molecular constitution of the solvent. The influence of solvent is due to the change of the adsorption quantity and adsorption intensity.
1992, 3(2): 129-132
Abstract:
The middle peak which appeared frequently on the voltammetric curves has been interpreted as the degradation of the polymer, according to the results of anion effect. When α-CD (α-cyclodextrin) was added in the acidic solution of aniline to form aniline-α-CD complex, the middle peak became even higher during electrochemical polymorization. This suggests that the middle peak is mot originated from cross-link or ortho-polymerization in aqueous acidic solution.
The middle peak which appeared frequently on the voltammetric curves has been interpreted as the degradation of the polymer, according to the results of anion effect. When α-CD (α-cyclodextrin) was added in the acidic solution of aniline to form aniline-α-CD complex, the middle peak became even higher during electrochemical polymorization. This suggests that the middle peak is mot originated from cross-link or ortho-polymerization in aqueous acidic solution.
1992, 3(2): 133-134
Abstract:
It was found for the first time that the compounds with only one functional group, such as pyridine, can show the promotion effect for the electrochemical reaction of cytochrome C at gold electrodes.
It was found for the first time that the compounds with only one functional group, such as pyridine, can show the promotion effect for the electrochemical reaction of cytochrome C at gold electrodes.
1992, 3(2): 135-136
Abstract:
The measurements of second harmonic generation efficiencies of some coordination compounds of lanthanide (Ⅲ) carboxylates and β-diketonates have been reported. The results show thatmost of lanthanide cinnamate have SHG activity.
The measurements of second harmonic generation efficiencies of some coordination compounds of lanthanide (Ⅲ) carboxylates and β-diketonates have been reported. The results show thatmost of lanthanide cinnamate have SHG activity.
1992, 3(2): 137-138
Abstract:
Solid state magic-angle-spinning nuclear magnetic resonance spectroscopy (MAS-NMR) has been used to probe the signal of 27Al in polyoxyaluminum pillared montmorillonite. The experimental results show that the polyhydroxy polymers are indeed the pillaring species.
Solid state magic-angle-spinning nuclear magnetic resonance spectroscopy (MAS-NMR) has been used to probe the signal of 27Al in polyoxyaluminum pillared montmorillonite. The experimental results show that the polyhydroxy polymers are indeed the pillaring species.
1992, 3(2): 139-140
Abstract:
A new kind of vanadium bronze with rich lithium (Li5V5O15) was prepared from Li2CO3 and V2O5 at 680℃ for 24 hrs. The charge and discharge curves of bronze electrode were determined in organic electrolyte. One mole of this material could be incorporated up to 4 mole lithium at 0.2mA/cm2 and 1.0V cut-off voltage, corresponding capacity about 340Ah/kg. Compared with the cell of Li/Li1+xV3O5 the cell of Li/new bronze had higher capacity, smoother discberge curve, but lower plateau voltage (about 1.8V). The cycling behaviour of this material was good. The electrode insertion reaction was controlled by the lithium diffusion process in the bronze. This new bronze could be used for low voltage rechargeable lithium battery.
A new kind of vanadium bronze with rich lithium (Li5V5O15) was prepared from Li2CO3 and V2O5 at 680℃ for 24 hrs. The charge and discharge curves of bronze electrode were determined in organic electrolyte. One mole of this material could be incorporated up to 4 mole lithium at 0.2mA/cm2 and 1.0V cut-off voltage, corresponding capacity about 340Ah/kg. Compared with the cell of Li/Li1+xV3O5 the cell of Li/new bronze had higher capacity, smoother discberge curve, but lower plateau voltage (about 1.8V). The cycling behaviour of this material was good. The electrode insertion reaction was controlled by the lithium diffusion process in the bronze. This new bronze could be used for low voltage rechargeable lithium battery.
1992, 3(2): 141-144
Abstract:
A systematic study of the structural and superconducting behavior of the high Tc compounds YBa1Cu1.9M0.1O7-y has been performed where M=Ti, V, Mn, Fe, Co, Ni, Zn, Zr, Nb, Mo, In and Sn. Structural analysis shows that most replacements somewhat modify the YBa2Cu3O7-y lattice parameters in the orthorhombic structure, with the exception of Fe and Co which transit into tetragonal phase. Although the 1D Cu-O chains are destroyed, the depressed Tc remain within 73 to 76K in the case of Fe and Co. However. the substitution of Ni and Zn on the Cu2 sites appears to strongly decrease Tc whereas their structure remains orthorhombic. This indicates that the 2D Cu-O planes play a very important role in the transportation of superconducting electrons but the 1D Cu-O chains play a role not only in supplying carrier number but also in coupling the Cu-O planes.
A systematic study of the structural and superconducting behavior of the high Tc compounds YBa1Cu1.9M0.1O7-y has been performed where M=Ti, V, Mn, Fe, Co, Ni, Zn, Zr, Nb, Mo, In and Sn. Structural analysis shows that most replacements somewhat modify the YBa2Cu3O7-y lattice parameters in the orthorhombic structure, with the exception of Fe and Co which transit into tetragonal phase. Although the 1D Cu-O chains are destroyed, the depressed Tc remain within 73 to 76K in the case of Fe and Co. However. the substitution of Ni and Zn on the Cu2 sites appears to strongly decrease Tc whereas their structure remains orthorhombic. This indicates that the 2D Cu-O planes play a very important role in the transportation of superconducting electrons but the 1D Cu-O chains play a role not only in supplying carrier number but also in coupling the Cu-O planes.
1992, 3(2): 145-148
Abstract:
A fluorescence enhancement phenomenon on adding terbium to the Eu or Sm-DBM-CTMAB-Triton X-100 fluorescence system was observed. The fluorescence intensity of this system was 50 times greater than that of the system without terbium at pH 9.0. The fluorescence intensity is a linear function of the concentration of europium or samarium in the range of 1.0×10-10-8.0×10-6 mol/L and 1.0×10-7-8.0×10-6 mol/L, respectively. The deteetion limits for them were 1.0×10-12 mol/L and 1.0×10-9 mol/L, respectively. This system was used for the determination of europium or samarium in rare earth samples with satisfactory results.
A fluorescence enhancement phenomenon on adding terbium to the Eu or Sm-DBM-CTMAB-Triton X-100 fluorescence system was observed. The fluorescence intensity of this system was 50 times greater than that of the system without terbium at pH 9.0. The fluorescence intensity is a linear function of the concentration of europium or samarium in the range of 1.0×10-10-8.0×10-6 mol/L and 1.0×10-7-8.0×10-6 mol/L, respectively. The deteetion limits for them were 1.0×10-12 mol/L and 1.0×10-9 mol/L, respectively. This system was used for the determination of europium or samarium in rare earth samples with satisfactory results.
1992, 3(2): 149-152
Abstract:
Fe3 (CO)12-derived Fe/r-AL2O3 and Fe/zeolite catalysts have higher catalytic activity than those derived from Fe(NO3)3. The existence of metal-metal bond in cluster species and the congruity of the adsorption of CO and H2 are important for increasing the catalytic activity. Carbon deposition for Fe5C(CO)15-derived Fe/r-AL2O3 catalyst is discussed.
Fe3 (CO)12-derived Fe/r-AL2O3 and Fe/zeolite catalysts have higher catalytic activity than those derived from Fe(NO3)3. The existence of metal-metal bond in cluster species and the congruity of the adsorption of CO and H2 are important for increasing the catalytic activity. Carbon deposition for Fe5C(CO)15-derived Fe/r-AL2O3 catalyst is discussed.
1992, 3(2): 153-156
Abstract:
Here some steady-state experiments on oxidation of CO on Pd were performed on a molecular beam apparatus. It is found that the characteristics of the rate of CO2 formation r versus substrate temperature T are dependent on the ratio P=PCO/PO2 in the mixed beam. These characteristics are related to the complicated interactions of co-adsorbed CO and O particles on Pd surface.
Here some steady-state experiments on oxidation of CO on Pd were performed on a molecular beam apparatus. It is found that the characteristics of the rate of CO2 formation r versus substrate temperature T are dependent on the ratio P=PCO/PO2 in the mixed beam. These characteristics are related to the complicated interactions of co-adsorbed CO and O particles on Pd surface.
