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Table of Content
24 April 1998, Volume 14 Issue 2
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Articles
A Study of Synthesis, Immobilization and Catalytic Capability of Metalloporphyrin
WANG Xing-qiao, GAO Shuang, CA Chang-sheng, YU Lian-xiang, GUO Jing-fu, SHUN Shu-ju, CAO Xi-zhang
1998, 14(2): 111-115.
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A stepwise-synthesis method was used to immobilize tetrachloro-tetramethyl porphyrins in the supercages of NaCoX molecular sieve. The immobilized porphyrin was characterized by means of UV-Vis, IR, DTA, SEM and EPR. A comparision was made for the activities among tetrachloro-tetramethyl porphyrins, its cobalt(Ⅱ) complex, NaCoX molecular sieve and the immobilized porphyrin as catalysts in the oxidation reaction of styrene and p-cresol. The stability and catalytic capability of the metalloporphyrin is increased after the combination of porphyrin with molecular sieve. In addition, this new type of catalyst tetrachloro tetramethyl porphyrin immobilized in the supercages of NaCoX molecular sieve not only possesses the advantages of both porphyrin and molecular sieve, but also makes up for their respective deficiencies. The experimental results confirmed that both the stability and catalytic capability of metalloporphyrin immobilized in the supercages of molecular sieve are increased.
Heteropolyacids Catalysis in Synthesizing Butylacrylate
ZHU Zhi-ping, ZHOU De-feng, LIU Jing-fu
1998, 14(2): 116-119.
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The catalytic activities of some heteropolyacids(HPAs) in synthesizing butyl-acrylate are reported. It has been demonstrated that 12-tungstophosphoric acid is the most effective catalyst among more than 20 HPA(salts). Various factors concerned in this reaction have been investigated. The optimum conditions have been found, that is, the molar ratio of alcohol to acid is 1.2∶1.0 , the catalyst concentration 1%(mass fraction), the reaction time 2 h, the temperature 98—124 ℃ and a certain amount of polymerization inhibitor exists.
The Solgel Preparation and Electric Properties of MnO
2
-doped PbTiO
3
Ceramics
QIANG Liang-sheng, FU Hong-gang, XU Chong-quan
1998, 14(2): 120-124.
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MnO
2
-doped PbTiO
3
ceramics was prepared by means of sol-gel method, its density and some electric properties were investigated. The results showed that it was feasible to prepare multicomponent PbTiO
3
sol-gel series with the aid of sol-gel method, the obtained MnO
2
-doped PbTiO
3
ceramics showed a high-purity, uniform component, better dense structure, hardly crack, and had good dielectric, piezoelectric, ferroelectric and pyroelectric properties.
Chemoselective Catalytic Hydrogenation of α,β-Unsaturated Ketones and α,β-Unsaturated Carboxylic Esters
ZHANG Jing-wen, ZHAO Jian-zhang, ZHANG Xiao-long, JIANG Yu-lin, MA Xiu-li, SUN Yun-xiu, JIANG Wen-pu, LI Yao-xian, XU Zhi-luo
1998, 14(2): 125-130.
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The effect of catalysts P-2.00-Ni(Nickel boride) and P-2.00-Ni-M(M: Co, Fe, Cu, Sn), prepared by adopting a modified recipe, on the chemoselective hydrogenation of carbon-carbon double bonds in α,β- unsaturated ketones, and the activity of catalysts P 1.80 Ni, P-2.00-Ni or P-1.80(2 00)-Ni-M(M: Pd, Co, Cu) in the selective hydrogenation of carbon-carbon double bonds in α,β-unsaturated carboxylic esters, were investigated systematically. According to the experimental results, the selectivities of these catalysts toward the hydrogenation of the carbon carbon double bonds of α,β-unsaturated keones or α,β-unsaturated carboxylic esters are 96%—100% or 100%, respectively.
Formation of Pyrrolidin-1-ylcyclopentadienes via Cyclization of Alkyl-2-Dimethoxyacetyl and 2-Ethoxalyl-4-oxopentanoates
ZHU Yi-qiang, TANG Hui-tong, ZHANG Pang
1998, 14(2): 131-137.
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The cyclizations of alkyl 2-dimethoxyacetyl and 2-ethoxalyl-4-oxopentanoates were only effected by means of pyrrolidine with the formation of appropriately substituted 1-pyrrolidin-1-ylcyclopentadienes.
Synthesis and Quantum Chemistry Studies of (R)-N-(Propionylthiazolidine-2-thione-4-methoxycarbonyl)germanium Sesquioxide
LI Ye-zhi, GUO Chun-xiao, ZHANG Li, HUANG Hua-min
1998, 14(2): 138-142.
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(R)-N-(β-Trichlorogermyl propionyl)thiazolidine-2-thione-4-carboxylic methyl ether(1) and its sesquioxide(2) were synthesized. The crystal structure of 1 was determined by means of X-ray diffraction analysis, which shown that the >C=O and >C=S groups are located in the opposite sides of C(4)—N—C(3) bond with trans configuration. The electronic structures and optimized configurations of compounds 1 and 2 were studied with MNDO method.
Isolation and Characterization of a Bioactive Polysaccharide from Panax Quinquefolium L.
MA Xiu-li, HAO Chun-yan, LU Shi-xiang, SUN Yun-xiu, LIU Ju-zheng, LIU Shu-ying
1998, 14(2): 143-146.
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Inactivity guided experiments, awater soluble polysaccharide PPQ5-2, which shows lymphocite stimulation and interleukin induction activieties, from Panax quinquefolium L. was isolated and characterized. It is composed of D-arabinose and D-galactose in amolar ratio of 1∶1.1 in alditol acetate derivatives analyzed by means of GC. Galacturonic acid was detected with GC. The elementary analysis showed about 8% of protein in it. The molecular weight is about 21 000 determined by matrix-assisted laser desorption/ionization mass spectrometry.
The Phenomenon of Mutual Media in Polypyrrole with Electroactive Ions
YANG Chun-he, DONG Shao-jun
1998, 14(2): 147-152.
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The dependence of the differential capacitance of polypyrrole doped with several typical dopants on potential is presented, which shows that the differential capacitance varies with the potential, the doped polypyrroles with electroactive ions give the largest capacitance near their formal potentials, which is attributed to the mutual media for electron transfer between polypyrrole and electroactive dopants. The existence of two conducting phases was observed in the complex capacitance plots. The electroactive anions act as an intra-conducting-phase medium for electron transfer, the electroactive cations act as an inter-conducting phase medium for electron transfer. The mutual media between polypyrrole and redox dopants lead to the increase of the discharging time.
Electrochemical Probe of Hydroxylation of 4-Nitrophenol by Cytochrome C with Hydrogen Peroxide
ZHU Yi-min, WANG Jin-cheng, LI Jing-hong, DONG Shao-jun
1998, 14(2): 153-159.
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The reaction of hydrogen peroxide with cytochrome c makes them coupled to lead to the hydroxylation of 4-nitrophenol. In situ electrochemical probe was used to detect the hydroxylation of 4-nitrophenol, which can avoid the tedious extraction procedure, the loss of the active species and the interference of some colored substances in the detection of 4-nitrocatechol by spectroscopic method. The hydroxyl radical scavengers mannitol and sodium benzoate did not eliminate hydroxylation, but the inhibitory effect of uric acid on the hydroxylation lead to the formation of the ferryl species of the protein during the reaction. These studies suggest that the electrochemical probe might efficiently detect the trace 4-nitrocatechol from the onset of the hydroxylation reaction and thus provides a more sensitive tool.
FAB MS of Permethylated L-β-Aspartamido-Carbohydrates
WANG Tsong-hui, CHEN T. F., Barofsky D. F.
1998, 14(2): 160-166.
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Native glycopeptides are suitable to FAB mass spectrometric analysis due to their high polarity, low volatility and large molecular size. The deficiency in the FAB spectra of glycopeptides is the limited number of peaks and the low abundances of fragments. In order to obtain the information of carbohydrate sequence the permethylation of carbohydrate, a well known method, is recommended here. The L-β-aspartamido-carbohydrate from chicken egg albumin was chosen as the model compound of glycopeptides. Our experiments showed obvious carbohydrate-sequence in the spectra of permethylated aspartamido carbohydrates. The key conditions to perform the method are the methylation reagent and purification process for the permethylated derivatives.
Studies on the Conformation of Poly(1-naphthol) Assembled by Horseradish Peroxidase in Aqueous Micelle
CHEN Song-ming, ZHANG Xue-zhong, CHAI Xiang-dong, LI Tie-jin
1998, 14(2): 167-170.
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FTIR, UV-visible , fluorescence spectra and calculation of CPK model indicated that poly(1-naphthol) synthesized and assembled by horseradish peroxidase(HRP) in aqueous micelle was constructed with orderly helical conformation, which was the lowest energy conformation of the polymer under this condition and resulted in an advanced π-conjugated system.
Sites of Protonation and Unimolecular Fragmentation of Protonated N-Hydroxyphthalimide in the Gas Phase
SHE Yi-min, SUN Yu-quan, JI Yi-ping, LIU Shu-ying
1998, 14(2): 171-175.
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The low energy collision induced dissociation, linked scan techniques and isotopic labeling experiment were used to investigate the unimolecular fragmentation of protonated N-hydroxyphthalimide under electron impact and chemical ionization conditions. It was found that this compound shows an unusual reactivity towards protonation. Two possible sites of protonation have been proposed to explain the corresponding fragmentation processes, one is that the protonation takes place on the oxygen atom of hydroxyl group, resulting in the loss of water and the other is the formation of an intermediary proton-bound complex in the fragmentation process, giving rise to the fragment ions of m/z 133 and m/z 135. The results show both cases are coexistence in the fragmentations of protonated N-hydroxyphthalimide, and the unimolecular fragmentation pathways are available.
Pillaring of Zn
2
Al Layered Double Hydroxide by Dawson Polyoxometalate Anions
GUO Jun, LI Yun-lun, JIAO Qing-ze, JIANG Da-zhen, MIN En-ze
1998, 14(2): 176-178.
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Zn2Al layered double hydroxide pillared with Dawson polyoxometalates, P
2
W
17
ZO
61
8-
(Z=Mn
2+
, Co
2+
, Ni
2+
, Cu
2+
, Zn
2+
) was prepared. A basal space of ca. 16 nm indicates the intercalated Dawson ions to be oriented with their C
2
axis perpendicular to the double hydroxide layers(with the exception of P
2
W
17
Zn-LDH). The IR and
13
P MASNMR spectral reveal that the Dawson ions retain their integrity in the interlayer space of LDH. A preliminary study shows that these compounds are highly active catalysts for the oxidation of cyclohexene with molecular oxygen.
Structures and Vibrational Spectra of C
2
and LaC
2
+
Clusters
WU Zhi-jian, MENG Qing-bo, ZHANG Si-yuan
1998, 14(2): 179-183.
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C
2
and LaC
2
+
were studied using Hartree Fock(HF), B3LYP (Becke 3-paremeter-Lee-Yang-Parr) density functional method, second order M φller-Plesset perturbation(MP2) and coupled cluster singles and doubles with non-iterative triples(CCSD(T)) methods. The basis set employed was LANL1DZ. Geometries, vibrational frequencies and other quantities were reported. The results showed that for C
2
, all the methods performed well for low spin state(singlet), while only HF and B3LYP remained so for high spin state(triplet). For LaC
2
+
, four isomers were presented and fully optimized. The results suggested that linear isomers with C
∞v
and D
∞h
symmetries were predicted to be saddle points on the energy surface for all the methods, while for isomers with C
2v
and C
s
symmetries, they were local minima except C
2v
at B3LYP level, and were isoenergetic at HF, MP2 and CCSD(T) levels, near isoenergetic at B3LYP level. From the differences between HOMO and LUMO, it is also known that the isomers with C
2v
and C
s
symmetries offer the largest values and therefore correspond to the most stable structure. ForLa—C bond lengths, B3LYP gives the shortest, the order is B3LYP<HF<MP2<CCSD(T) for all the methods.
Studies on the Lanthanum-Modified Lead Titanate Ultrafine Particles by Raman Spectroscopy
CUI Ai-li, GE Xu-dong, HU Yong-qi, JIN Yong, WANG Xiao-hui
1998, 14(2): 184-187.
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Lanthanum-modified lead titanate(PLT14) ultrafine particles were synthesized by means of stearic acid gel method. The structure of the samples was characterized using X-ray diffraction(XRD) and TEM. The crystal graphic parameters of the samples were calculated. The Raman spectra of PLT14 powders at a high pressure as well as a high temperature reveal that the phase transition pressure or temperature shifts to a lower pressure or temperature with the decrease of grain size.
Ab Initio Studies on the Structure and Binding Interaction of M
+
CO
2
(M=Sc, Ti…Zn)
FAN Hong-Jun, ZHONG Shi-Jun, LIU Chun-Wan
1998, 14(2): 188-193.
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The geometry and binding interaction of M
+
CO
2
(M represents the first row transition metals) were studied using ab initio methods. In some cases the frequency calculations and basis set superposition error corrections were included. For all the complexes under the study, the linear structures were found to be the equilibrium structure. The distances of M
+
—O in R(M
+
—O) in which M has 4s electrons are obvious longer than those in which M has no 4s electrons, and from Sc to Zn the change trend is decreased, accompanied with some oscillation. The binding energy has an opposite change trend to that of the R(M
+
—O). Linear M
+
CO
2
has the same spin as M
+
, while T-shape structures may have different spins. The static electronic interaction was found to be about 80% of the total binding energy.
Syntheses of Cellulose-Type Polysaccharide by Means of Ring-Opening Copolymerization of Anhydroriboses ABRP and AIRP
WU Cheng-pei, PAN Cai-yuan, Toshiyuki-Uryu
1998, 14(2): 194-198.
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Two kinds of 1,4-anhydroribose derivatives, 1,4-anhydro 2,3-O-benzylidene-α-D-ribopyranose （ABRP） and 1,4-anhydro 2,3-O-isopropylidene α D ribopyranose （AIRP） were prepared from D-ribose. The ring-opening copolymerizations of ABRP and AIRP in various feed ratios were carried out with SbCl
5
and BF
3
OEt
2
as catalyst at low temperatures. The copolymer structure was characterized by means of
1
H,
13
C NMR spectroscopy and specific rotation. When SbCl
5
was used as catalyst, the copolymer obtained had completely 1,4-β-pyranosidic structure, i.e., cellulose type structure. However, when BF
3
OEt
2
was used as catalyst, the copolymer had a mixed structure of furanosidic and pyranosidic units.
Studies on Liquid Crystalline Bis[4-(p-phenoxy)-phenylbenzoate]-Alkyldicarboxylate
XING Pei-xiang, TIAN Yan-qing, WANG Jun-zuo, NA Hui, TANG Xin-yi, JIANG Bing-zheng
1998, 14(2): 199-203.
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A new series of liquid crystals of bis[4-(p-phenoxy)-phenylbenzoate]-alkyldicarboxylate which contain two rigid groups connected by a flexible spacer was synthesized. These liquid crystals show nematic phase and were found to show odd even effect in isotropization temperature and entropy change.
Studies on Free Radical EPR, Superoxide Dismutase Water-soluble Lipidperoxide in Tears
YUAN Yi, ZHAO Shi-hong, YANG Shou, CUI Ya-nan, ZHANG Rei-xue
1998, 14(2): 204-209.
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By means of electron paramagnetic resonance(EPR), chemistry luminescence and fluorescent spectroscopy, the free radical, superoxide dismutase and water soluble lipid peroxide in tears of normal eyes(150 eyes, 100 cases), Moorens ulcer(9 eyes), coreal grafts rejection(16 eyes) were studied. The results showed that the spin density of the free radical was 3.6(±0.58)×10
12
spins/mL tear, the content of the superoxide dismutase(SOD) was 3.84(±1.45) ng/mL tear, the opposite fluorescent density of the water soluble lipid peroxide was 12.912(±1.691) U/mL tear in normal tears. The normal values are 2.5—4.8×10
12
spins/mL tear for free radical, 2.39—5.29 ng/mL tear for SOD, 9.598—16.225 U/mL tear for water soluble lipid peroxide. There are significant differences in different eyes, different sexes and different ages. The free radical and lipid peroxide are higher obviously in the tears of patients with Moorens ulcer and rejected corneal grafts, compared with those of the normal control subjects(P<0.01), SOD is lower evidently(P<0.01). The above fact shows the pathogenic mechanism of Moorens ulcer and keractoplasty rejection is significantly related to toxicities injuring effect of the free radical. These results have provided important experimental data for studying lacrimalogy and new methods for clinical diagnosis and treatrment.
Synthesis and Characterization of Liquid Crystal of meso-Tetra(4-n-octanoyloxyphenyl)porphyrin
LIU Wei, SHI Tong-shun
1998, 14(2): 210-212.
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Preparation of Indolizine by Intramolecular 1,5-Dipolar Cycloaddition of Pyridinium N-Allylides
ZHOU Jian, HU Yue-fei, HU Hong-wen
1998, 14(2): 213-214.
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A Molecular Orbital Study of No Adsorption on Magnesium Oxide
LU Xin, XU Xin, WANG Nan-qin, ZHANG Qian-er
1998, 14(2): 215-217.
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Isolation and Identification of Flavone Type of Two Compounds from Salix matsudana
LIU Mo-xiang, ZHENG Yi-nan, LIU Xiao-feng, LI Xiang-gao, XIANG Lan
1998, 14(2): 218-220.
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Formation of Self-organization InAs Quantum Dots on (001) InP Substrate by As/P Exchange Reaction in MOCVD
WANG Ben-zhong, ZHAO Fang-hai, PENG Yu-heng, JIN Zhi, LI Yu-dong, YANG Shu-ren, LIU Shi-yong
1998, 14(2): 221-224.
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Editor-in-Chief:
Jihong YU
ISSN 1005-9040
CN 22-1183/O6
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