Chemical Research in Chinese Universities

Synthesis and Magnetic Properties of Binuclear Mn(Ⅱ) Complexes with Alkoxide Bridge

Yan Shi-ping, Fan Bo, Liao Dai-zheng, Jiang Zong-hui, Wang Geng-lin

1994, 10(2): 63-67.

Abstract ( )

PDF (2323KB) ( )

Related Articles | Metrics

Five binuclear Mn(Ⅱ) complexes were synthesized, namely [Mn₂LCl]Cl₂·H₂O (1), [Mn₂LphCOO] (ClO₄)₂ (2), [Mn₂LOH] (ClO₄)₂·C₂H₅OH (3) ,[Mn₂LC₂H₅O](ClO₄)₂·H₂O (4), and [Mn₂L(SCN)₃]·2C₂H₅OH (5), where HLis 1:2 Schiff bases derived from 1, 3-diaminopropan-2-ol and picolinaldehyde N-ox-ide.Based on the IR, elemental analyses and conductivity measurement, these com-plexes are proposed to have an endogenous bridge (alkoxide) and an exogenousbridge (it can be an anion).The complexes (3) and (4) were characterized by vari-able temperature magnetic susceptibility (4300 K) and the data were fitted by theleast-squares to a susceptibility equation derived from the spin Hamiltonian, H =-2J·S₁·S₂.The exchange integral J, was found to be 1.19 cm^-1 for (3) and 1.06 cm^-1 for (4), indicating that a weak antiferromagnetic exchange is presentin the binuclear Mn(Ⅱ) complexes.

Studies on Ion-Beam Modified Hydrogen Evolution Electrodes

Zhang Ji-shuang, Li Qin-lian, Lu Yao-jiao, Yan Xi-yun, Hou Rang-kun

1994, 10(2): 68-71.

Abstract ( )

PDF (2295KB) ( )

Related Articles | Metrics

The present paper focuses on the modifying effects of ion beam mixing, ion im-planting and ion sputtering on hydrogen evolution electrodes.It was discovered thatthe four types of electrodes possessed excellent catalytic activity in acid or alkalinemedia and potential stability in long term electrolysis of water under high currentdensity.Their stability and applying life-span greatly surpass those of other elec-trodes activated by electrodepositing and other method.The effects of temperatureand roughness on function of electrodes were also examined.XPSand AESwereapplied to analyse the surface composition and bond states of the electrodes, andthe distribution of concentration varying with depth, and to explain the law of theexperiments .

Electrochemical Scanning Tunneling Microscopy──An Ex-situ Study of the Growth of Polypyrrole Films on Electrodes

LI Jing, WANG Er-kang

1994, 10(2): 72-78.

Abstract ( )

PDF (518KB) ( )

Related Articles | Metrics

This paper covers the electropolymerized polypyrrole doped with p-toluenesul-fonate studied using scanning tunneling microscope.The growth processes of polypyrrole films on the electrode surface were observed.Polypyrrole chain struc-ture with many separated micro-holes of 0.15 nm diameter at the initial state ofelectropolymerization can be seen from obtained STM images.This structure is ex-tremely similar to the pioneer-proposed ideal structure of polypyrrole chains.Thereexisted some helical structure and simple strands on the electrode surface, which isdue to different existing states of polypyrrole chains on electrode surface.STM ex-periments showed that polypyrrole chains were firstly formed on the electrode sur-face, then, they growed gradually by 3-dimensional mode during slow oxidation toform many separated micro-islands.Finally, a large corrugation area of polymerfilms occurred on the electrodes.

Microcomputer Simulation of Elution Behaviour for Dicarboxylic Acids in Ion-Exclusion Chromatography

Zhao Guo-liang, ZHAO Yu-ming, Liu Li-na

1994, 10(2): 79-84.

Abstract ( )

PDF (2379KB) ( )

Related Articles | Metrics

The present paper covers a model involving Donnan memhrane equilibrium andadsorption eluilibrium to describe the retention process for diprotic organic acids inion-exclusion chromatography.On this basis the microcomputer simulation of elu-tion behaviour for dicarboxylic acids was investigated.Influences of eluent acidityand sample concentration on the retention value were studied.The theoreticallypredicted results are in reasonable agreement with the experimental data.

Carbon Paste Electrode Modified by Surfactant for Anodic Stripping Voltammetric Determination of Sulphadiazine

Zhang Zheng-qi, Chen Zhan-guang, Chen Sheng-zong, TAO Mei-juan, ZHANG Hong

1994, 10(2): 85-92.

Abstract ( )

PDF (2475KB) ( )

Related Articles | Metrics

The present paper covers the construction and behaviour of a mixed binder car-bon paste electrode modified by surfactant system appropriate for the anodic strip-ping voltammetric quantitation of sulphadiazine.The mixed binder consisted ofglycerol and liquid paraffin.On this electrode in a PH 8.20 buffer solution sulpha-diazine yields a sensitive anodic stripping voltammetric wave at 0.82 V.It can beused for the determination of trace amounts of drug, the linear range of the peakcurrent to the sulphadiazine concentration being from 1.0 × 10^-7 to 5.0 × 10^-5 mol/L, and the detection limit being 6.6 × 10^-9 mol/L with a relative standard de-viation of 2.6% (n= 15).The proposed method was used to determine the drug inurine samples.

A Facile Synthesis of Indolizines by 1,3-Dipolar Cycloaddition of Pyridinium and Related Heteroaromatic Ylides with Alkenes in the Presence of TPCD, Py₄Co(HCrO₄)₂

ZHU Chang-cheng, WEI Xu-dong, HU Jia-xin, WANG De-fen, HU Hong-wen

1994, 10(2): 93-101.

Abstract ( )

PDF (483KB) ( )

Related Articles | Metrics

A facile one-step method is presented for the synthesis of indolizines in moder-ate to high yields by reaction of pyridinium, quinolinium and isoquinolinium ylideswith acrylonitrile, methyl acrylate and diethyl maleate respectively in the presenceof tetrakis-pyridino-cobalt(Ⅱ)dichromate (TPCD) in DMF.

Synthesis and Structure of(NH₄)₂ [V₂O₄(OCH₂COO)₂]

ZHOU Zhao-hui, WANG Jinzhi, WAN Hui-lin, TSAl Khi-rui

1994, 10(2): 102-106.

Abstract ( )

PDF (2276KB) ( )

Related Articles | Metrics

Dimeric ammonium(glycollate)dioxovanadium (NH₄)₂[V₂O₄(OCH₂COO)₂]has been prepared.The complex crystallizes in triclinic space group P1 with unitcell parameters: a = 0.6124(1)nm, b= 0.6952 (1)nm, c= 0.8449 (1)nm, α=66.08 (1),β=64.21(1),γ= 78.01(1)°V=0.2958 nm³, Z=1, R=0.041.Thedimer contains a quasicentrosymmetric planar four-membered V₂O₂ ring with twoexocyclic glycollate entities coordinated by the oxygen atoms of hydroxy-and car-boxy late ligands.

Quantum Chemistry Study on Structures of ClusterIons Nb_nS_m^± Generated by Laser Mass Spectra

MA Yan-hui, LIN Meng-hai, ZHENG Lan-sun, LIU Hong-lin

1994, 10(2): 107-114.

Abstract ( )

PDF (2440KB) ( )

Related Articles | Metrics

According to the chemical bond theory we designed geometric structures ofcluster ions Nb_nS_m^± generated by laser ablation and calculated their electronic struc-tures using DV-X_a method of quantum chemistry.The results show that with theincrease of the cluster size the structures of the cluster ions change from a single-chain to a double-chain, then to a planar-net, and linking up to a net at Nb₃.Thenegative cluster ions tend to form a divergent configuration due to the extra chargeson it.

The Electronic Structures and Catalytic Activities of Triruthenium Ketenylidene ClustersSupported on Oxides

LI Zhi-ru, XIAO Feng-shou, ZHANG Yun-han, WEI Jia-you, LI Jun, FENG Ji-kang, XU Ru-ren

1994, 10(2): 115-119.

Abstract ( )

PDF (2281KB) ( )

Related Articles | Metrics

The catalytic activities of [H_nRu₃(CO)₉(CCO)]^-(2-n)(n=0, 1, 2, 3) support-ed on oxides have been estimated using INDO calculations and correlation betweencatalytic activity and electronic structure for these clusters have been established.The activity in ¹³CO isotopic exchange strongly relates to the bond orders of Ru-CO and C-CO, and the activity in alkylation with nucleophile or electrophile de-pends mainly on the net charges at C_β atoms.In addition, the possible species of [H₃Ru₃(CO)₉(CCO)]⁺ has been proposed although it has not been synthesized upto now.

Adsorption of Benzene on the Potassium Exchanged Hbeta Zeolites

SHEN Jian-ping, MA Jun, SUN Tie, JIANG Da-zhen, MIN En-ze

1994, 10(2): 120-125.

Abstract ( )

PDF (2374KB) ( )

Related Articles | Metrics

In situ IR studies of benzene adsorbed on different potassium-exchanged degrees of KHβ zeolites were carried out under different conditions.The bands of adsorbed benzene on KHβ zeolites in the range of 2050-1750 cm^-1 were assigned.The KHβ zeolite has basicity only when the ratio of K to AI of KHβ is up to 88.39%, its basicity is stronger and its acidity is weaker.The order of stability ofthe adsorbed benzene species on the samples is O_b^->H_b⁺>K_b⁺>b.

Silica-supported Polysiloxane with Selenacrown Ether Moieties and Its Platinum Complex

LU Xue-ran, ZHANG Li-feng, WANG Zhen-xia, LIU Xiu-fang, CHEN Yuan-yin

1994, 10(2): 126-130.

Abstract ( )

PDF (2324KB) ( )

Related Articles | Metrics

The present paper covers syntheses of the first functionalized selenacrownether, allyloxymethyl-1-selena-4, 7, 10, 13, 16-pentaoxacyclooctadecane, and its im-mobilized product, silica-supported polypropyloxymethyl-1-selena-18-C-6 siloxane.It was found that the immobilized selenacrown ether could coordinate with platinumsalt and the platinum complex was a new type of polymeric hydrosilylation catalyst.The polymer catalyst exhibited a high catalytic activity for the hydrosilylation ofolefins with triethoxysilane in the temperature range of 60 to 110℃.The turnovernumber could amount to more than 100,000 in one run.

Studies on Artificial Imitation of Glutathione Peroxidase by Chemical Mutation

DING Lan, ZHU Zhen-qi, LUO Gui-min, SUN Qi-an, YANG Tong-shu, SHEN Jia-cong

1994, 10(2): 131-133.

Abstract ( )

PDF (2204KB) ( )

Related Articles | Metrics

After the alcoholic group of serine located in the binding site of Anti-HumanIgM(Fcμ) (Rabbit IgG) was selectively activated by phenylmethylsulfonyl fluoride(PMSF) and displaced with hydrogen selenide(H₂Se), the serine residue was con-verted to selenocysteine(SeCys).Because SeCys is a catalytic group of glutathioneperoxidase (GPX), the mutated antibody has the GPXactivity which is seventytimes more than that of PZ51, the best GPX mimic in the world.Moreover, themutated antibody remains its original antibody titer.

Recognition of Protein Native Folds Using a Continuous Potential Function

WANG Yu-hong, LU Zhi-bin, LI Wei

1994, 10(2): 134-140.

Abstract ( )

PDF (2390KB) ( )

Related Articles | Metrics

We report a simple continuous potential function that can recognize proteinchains' native folds from tens of thousands of alternative ones.Empirical parame-ters for this potential function were obtained by a neural network learning oversamples generated from PDBstructural data.Hydrophobic interactions were foundto be mainly responsible for stabilization of the protein' s native fold.The inter-chain interaction was found indispensable in stabilizing some protein chains' nativeconformation.

Synthesis of Single Crystals of Zeolite Betaby Using Two Silica Sources

SUN Yan, SONG Tian-you, QIU Shi-lun, PANG Wen-qin

1994, 10(2): 141-143.

Abstract ( )

PDF (225KB) ( )

Related Articles | Metrics

Monte Carlo Simulation of Band Texture Formation in Macroscopically Oriented Semirigid Polymer System

Zhang Hong-dong, YAN Dong, YANG Yu-liang

1994, 10(2): 144-145.

Abstract ( )

PDF (2143KB) ( )

Related Articles | Metrics