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Table of Content
24 August 1998, Volume 14 Issue 3
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Articles
Hydrothermal Synthesis and Characterization of Per ovskite PbTiOs
3
Powders from Different Precursors
CHEN Dai-rong, XU Ru-ren
1998, 14(3): 225-229.
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Perovskite-type of PbTiO
3
fine powders which are homogeneous in physic-chemical properties has been hydrothermally synthesized from the different precursors. The borderline reaction conditions, such as temperature and time, for the formation of PbTiO
3
were established and the effect of the precursor on the particle properties was investigated. As a precursor, Pb-Tialko-carbonate xerogel dispersed in 2-methoxyethanol was found to be effective for the synthesis of the PbTiO
3
powders with a lower agglomeration and a simple mode of particle-size.
Synthesis, Structure and Magnetic Properties of Novel Carboxylato bridged Pentanuclear Copper(Ⅱ)-Lanthanoid(Ⅲ) Complexes
TONG Ming-liang, WU Yu-luan, CHEN Xiao-ming, SUN Zi-ming, David N. Hendrickson
1998, 14(3): 230-235.
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Six novel pentanuclear complexes [Cu
3
Ln
2
(ClCH
2
CO
2
)
12
(H
2
O)
8
]·2H
2
O (Ln=La, Pr, Sm, Gd, Dy, or Er) were synthesized by the reaction of chloroacetic acid with Cu and Ln ions in aqueous solutions. The X ray crystallography established the structure of the Gd complex, which contains a pair of quadruply acetato bridged CuGd dinuclear subunits, and each of them is linked to the central Cu atom by a single acetato bridge. The coordination sphere of each Gd atom is completed by three aqua ligands [Gd-O=0.242 8(5)-0.244 4(4) nm] to form an 8 coordinated distorted square antiprism. The central Cu atom is coordinated by two oxygen atoms from the two bridging acetato groups and two oxygen atoms from the two monodentate acetato groups in a slightly distorted square planar fashion, while each terminal Cu atom is coordinated by the four acetato oxygen atoms at the basal plane and an aqua ligand at the apical position to form a square pyramid. The variable temperature (4 320 K) magnetic susceptibility data of the Gd complex were measured, and fitted to the Curie Weiss law with C =16.38 K cm
3
·mol
-1
and θ =-1.55 K, indicating very weak antiferromagnetic interaction.
Synthesis and Structure of Tungsten(Ⅵ) citrate Complex K
6
[W
2
O
5
(cit)
2
]·5H
2
O
XING Yong-heng, XU Ji-qing, SUN Hao-ran, WANG Zhuo, HUANG Xiao-ying
1998, 14(3): 236-240.
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A new tungsten(Ⅵ) citrate complex K
6
[W
2
O
5
(cit)
2
]·5H
2
O which differs from Nasub>6[W
2
O
5
·(cit)
2
]·10H
2
O, was synthesized by means of an aqueous solution reaction of (NH
4
)
2
WS
4
and K
3
cit. The single crystal X-ray diffraction study showed that the crystal belongs to a triclinic system. The space group is P
-
1 with a =1.186 8(3) nm, b =1.371 8(7) nm, c =1.025 3(3) nm; α =107.79(4)°, β =99.27(2)°, γ =66.30(2)°, V =1.454(2) nm
3
, Z =2. The complex anion contains a O
2
WOWO
2
skeleton with a bridging oxo group and two citrate ligands. Each citrate as a terdentate ligand coordinates to one tungsten atom by means of the deprotonated hydroxy, α-carboxylate, and β-carboxylate groups.
Photochemical Synthesis and Magnetic Property Investigation of a Mixed-valence 11-Tungstophosphate
LI Pei, LIU Hui-zhang, JIN Song-lin, XIE Gao-yang
1998, 14(3): 241-244.
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A mixed-valence lacunary tungstophosphate with Keggin structure was photochemically synthesized. It was proved to be an one-electron reduced heteropoly "blue" by W(V) analysis. The subsequent changes were observed in the UV-Vis, IR and
31
P NMR spectra of the mixed-valence species due to the introduced "blue" electron. The magnetic property investigated by means of the Evans method suggested that the "blue" electron was fully delocalized over the framework of the mixed-valence lacunary tungstophosphate, and the vacancy in the lacunary species did not transmit the circulating electron, which thus blocked "ring current" in some intersecting loops.
The Luminescence Properties and Intramolecular Energy Transfer of Rare Earth Complexes with Aromatic Carboxylic Acids
YAN Bing, ZHANG Hong-jie, NI Jia-zuan
1998, 14(3): 245-249.
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The triplet state energies of para aminobenzoic acid and nicotinic acid were determined by means of low temperature phosphorescence spectrometry. The energy matches between them and the resonant emitting energy levels of Eu
3+
, Tb
3+
, Sm
3+
, Dy
3+
were studied. The intramolecular energy transfer processes from the two aromatic carboxylic acid ligands to rare earth ions were also discussed on the basis of the measurement results of luminescence intensities, lifetimes and quantum efficiencies.
Bright Red Organic Electroluminescent Devices Based on a Soluble Rare Earth Complex Eu(TTA)
3
Phen
LI Bin, MA Dong-ge, ZHANG Hong-jie, ZHAO Xiao-jiang, NI Jia-zuan, FU Chun-yan
1998, 14(3): 250-253.
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An Electroluminescent device with PVK film doped with Eu(TTA)
3
Phen and PBD was fabricated. The device structure of glass substrate/indium tin oxide/PPV/PVK∶ Eu(TTA)
3
Phen∶PBD/Alq
3
/Al was employed. A sharply red electroluminescence with a maximum luminance of 56.8 cd/m
2
at 48 V was achieved.
Synthesis, Characterization and Catalysis of New Pillared Anionic Clays by [GaW
11
O
39
M(H
2
O)]
7-
(M=Mn
2+
,Co
2+
or Ni
2+
)
ZHU Zhi-ping, PENG Wan-pu, ZHOU De-feng, LIU Jing-fu
1998, 14(3): 254-258.
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Pillared anionic clays or layered double hydroxides were prepared by means of hydrothermal ion exchange reaction of [Zn
2
Al(OH)
6
]NO
3
· x H
2
O (ZnAl NO
3
) with [GaW
11
O
39
M(H
2
O)]
7-
(abbreviated as GaW
11
M, M=Mn
2+
, Co
+2
or Ni
2+
). The layered compounds were characterized by means of XRD, IR, elemental analysis and DTA. The X-ray diffraction and IR spectra show that the new anionic clays synthesized are layered compounds with the gallery heights of 0.99-1.00 nm and the Keggin structure tungstogallic heteropolyanions almost completely replace the interlayer NO
3
-
, entering the layer and retain their Keggin structure. The DTA gives a thermostability order of ZnAl GaW
11
Ni >ZnAl-GaW
11
Co>ZnAl-GaW
11
Mn>ZnAl-NO
3
. The ctalytic tests showed that the new pillared compounds have higher catalytic activities in the cyclooxidation reaction of maleic acid.
Spectrofluorimetric Determination of Trace Amounts of Gallium with Salicylaldehyde Benzoylhydrazone
TANG Bo, WU Chang-ju, WANG Hong-jian, YEN Jian-chong
1998, 14(3): 259-263.
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The fluorescent reagent salicylaldehyde benzoylhydrazone(SABH) was synthesized and its ionization constants were estimated spectrophotometrically. The fluorescent reaction of this reagent with gallium was studied. Based on this chelation reaction, a spectrofluorimetric method was developed for the determination of gallium in a water medium at pH 3.2. Under these conditions, the Ga-SABH complex has excitation and emission maxima at 372 and 455 nm, respectively. The linear range of the method was 0～150 μg/L and the detection limit was 0.36 μg/L of gallium when a standard addition method was used in the assay. The molar ratio of gallium to the reagent was 1∶3. The interference of other ions was studied. The extraction with n-butyl acetate from a 6 mol/L hydrochloric acid medium was used to separate Ga from the interfering elements in semiconductor silicon and geological samples, and themethod has been successfully applied to the determination of gallium in these samples.
In situ Microscopic FTIR Spectroelectrochemical Study of the Reduction of K
3
Fe(CN)
6
in Polymer Electrolyte
GUO Li-ping, LIN Xiang-qin
1998, 14(3): 264-269.
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Cyclic voltammetry and in situ microscopic FTIR spectroelectrochemistry were used for the electrochemical and vibrational characterizations of the reduction process of K
3
Fe(CN)
6
in polyethylene glycol(PEG) with LiClO
4
as supporting electrolyte at a Pt microelectrode. The rate of electron transfer is a function of the concentration of the supporting electrolyte. The redox potentials and cyclic voltammetric currents vary with Li/O molar ratio. The in situ spectroelectrochemistry shows that the infrared spectra are influenced by the concentration of LiClO
4
. The bridging cyanide groups with a structure Fe
Ⅱ
—C≡N…Fe
Ⅱ
—C≡N are formed during the reduction process of K
3
Fe(CN)
6
. There may be an activated complex between the Li
cation and the complex anion.
Chemical Constituent of Natural Body of Armillaria mellea and Structure of 5,6-Epoxy-22-en-3-ol-ergosterol
SHI Lei, CAO Rui-min, LU Shi-xiang, WU Guang-xuan
1998, 14(3): 270-272.
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The Addition Reaction of p-Chlorobenzaldoxime Dehydrodimer with 1,3-Dienes
ZHANG Xu, WEI Xu-dong, HU Yue-fei, HU Hong-wen
1998, 14(3): 273-276.
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The addition reaction of p-chlorobenzaldoxime dehydrodimer and 1,3-dienes in refluxing chloroform gives linear 1,4-addition products. The reaction is probably a free radical process.
Synthesis and Characterization of Specific Haptens Used to Generate Abzyme with Glutathione Peroxidase Activity
Liu Jun-qiu, Gao Shu-juan, Luo Gui-min, Shen Jia-cong
1998, 14(3): 277-279.
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Glutathione was modified selectively by 2,4-dinitrochlorobenzene, giving S-substituted dinitrophenyl glutathione(GSH-S-DNP). GSH-S-DNP was further esterified by iso-butanol, hexanol, cyclohexanol and benzyl alcohol. Four haptens used to generate abzyme with glutathione peroxidase(GPX) activity were synthesized. They are GSH-DNP biesters: GSH-DNP-diiso-butyl ester(GSH-DNP-IBU), GSH-DNP bihexyl ester(GSH-DNP- HE), GSH-DNP bicyclohexyl ester(GSH-DNP-CH), GSH-DNP-bibenzylmethyl ester(GSH-DNP-BE). The structures of the haptens were characterized by means of elemental analysis, IR and
1
H NMR.
Catalytic Oxidative Dehydrogenation of Isobutane over KF-Zn
3
(PO
4
)
2
HUANG Yan, WANG Guo-jia, YU Jian-feng, YANG Hong-mao, WU Tong-hao, DUAN Shu-hong, PENG Shao-yi
1998, 14(3): 280-283.
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KF-Zn
3
(PO
4
)
2
catalyst was found to be effective for isobutane oxidative dehydrogenation into isobutene. The effects of O
2
concentration in feed gas on isobutene yield and selectivity were discussed. The modification of zinc phosphate by potassium fluoride leads to the formation of a new compound KF-Zn
3
(PO
4
)
2
and surface basic sites, the catalytic performance of which is thus improved.
Hydrodesulfurization of Thiophene on Ni,Mo-supported MCM-41 Catalysts
CUI Jun, YUE Ying-hong, SUN Yu, DONG Wei-yang, GAO Zi
1998, 14(3): 284-288.
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MoO
3
and NiO supported MCM-41 and AlMCM-41 catalysts were prepared. The XRD and N
2
adsorption/desorption results show that MoO
3
was more readily dispersed on the supports than NiO. The activities of the catalysts for thiophene hydrodesulfurization are strongly affected by the block of the unidimensional mesoporous channels with oxide crystallites and/or extra-framework impurities. Mo-supported MCM-41 catalysts are more active for hydrodesulfurization than Ni-and Ni, Mo-supported MCM-41 catalysts.
Normal Mode Analysis on Three Different Structures of a Duplex DNA d(CGCGAATTCGCG)
LIN Dong-hai, LIAO Xin-li
1998, 14(3): 289-293.
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Normal mode analysis in dihedral angle space was carried out on two X-ray crystal structures and one model structure responded to the same sequence of duplex DNA: d(CGCGAATTCGCG). Comparing these results indicates that it is reliable and meaningful to carry out normal mode analysis on model structures. The reliability is greater except for the ends of helix.
The Active Sites of the Reference Phase of SmVO
4
as Catalyst for Propane Oxidative Dehydrogenation
ZHANG Wei-de, AU Chak-tong, LI Ji-tao, WAN Hui-lin
1998, 14(3): 294-296.
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The active sites of samarium orthovanadate(SmVO
4
) were studied by means of ESR, NO TPD and temperature programmed
18
O
2
-isotope exchange(TPIE) methods. The results of ESR and NO-TPD confirm the presence of V
4+
in the catalyst. The TPIE revealed that the
18
O
2
-isotope exchange was carried out through a single exchange procedure. The V
4+
species associated with oxygen vacancies are the sites for O
2
activation.
Valence Bond Study of Dissociation Behavior and Spectroscopic Constants for the Ground States of LiF and NaF
CAO Ze-xing, WU Wei, ZHANG Qian-er
1998, 14(3): 297-303.
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Ab initio VB calculations were used to determine the accurate spectroscopic parameters of the ground states of LiF and NaF. A set of potential energy curves corresponding to the ground states including ionic and covalent interactions, pure ionic interaction and covalent interaction were generated using the VBSCF method. Curve crossing in the dissociation processes of LiF and NaF was discussed. The optimized VB wave functions suggest that LiF and NaF are of high ionicity, and their ionic weights are 86.2% and 94.6%, respectively. NaF has a higher ionicity. The main difference between atom F and ion F
-
and the effect of the proper description of this difference on dissociation energies were investigated.
The Influence of Muffin-tin Approximation on Energy Band Gap
WU Zhi-jian, MENG Qing-bo, ZHANG Si-yuan
1998, 14(3): 304-308.
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)
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The influence of muffin-tin approximation on energy band gap was studied using LMTO-ASA (Linear Muffin-Tin Orbital-Atomic Sphere Approximation) approach. Since the diverse data are available for LaX(X=N, P, As, Sb), they are presented in our research as an example in order to test the reliability of our results. Four groups of muffin-tin radii were chosen, they were the fitted muffin tin radii based on the optical properties of the crystals (the first), 1∶1 for La∶X(the second), 1 5∶1 for La∶X(the third), and a group of radii derived by making the charge in the interstitial space to be zero(the fourth). The results show that the fitted muffin-tin radii (the first group) give the best results compared with experimental values, and the predicted energy band gaps are very sensitive to the choice of muffin tin radius in comparison with the other groups. The second and the third delivered results somewhere in between, while the fourth provided the worst results compared with the other groups. For the same crystal, with the increase of muffin-tin radius of lanthanum, the calculated energy band gaps decreased, going from semi-conductor to semi metal. This again clearly indicated the sensitivity of energy band structure on muffin-tin approximation.
Preparation and Properties of Water-based Conducting Polyaniline
WANG Xian-hong, GENG Yan-hou, YU Lei, SUN Zai-cheng, Li-Ji, JING Xia-bin, WANG Fo-song, LEE Chang-jin, RHEE Suh-bo-ng
1998, 14(3): 309-314.
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A convenient way to prepare water-soluble or water-dispersible conducting polyaniline was developed by employing protonic acid dopants containing hydrophilic ethyleneoxide oligomer as counter-ion. The conducting polyaniline possesses electrical conductivity in the range of 10
-3
to 10
-2
S/cm depending on the chosen dopant, and it displays an excellent electrochemical redox reversibility in non-aqueous systems.
The Rheological and Extrusion Behaviour of Blends Based on Phenolphthalein Poly(ether-ether-sulfone) and Thermotropic Liquid Crystalline Polymer
DI Ying-wei, D'AMORE Alberto, NICOLAIS Luigi, ACIERNO Domenico, NOBILE Rossella, LI Bin-yao
1998, 14(3): 315-323.
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A novel engineering thermoplastic, phenolphthalein poly(ether-ether-sulfone)(PES-C) was blended with a commercial thermotropic liquid crystalline polymer(TLCP), Vectra A950, up to 30 weight percent of TLCP. A rheometrics dynamic spectrometer (RDS-Ⅱ) and a CEAST capillary rheometer, a rheoscope 1000 were employed to investigate the melt rheology and extrusion behaviour at both the low and high shearing rates. The morphologies of the blends under different shearing were observed with a scanning electron microscope(SEM) and correlated to the observed rheology. The principal normal stress differences measured with cone-and-plate geometry give a temperature-independent correlation for both blend and PES-C when they are plotted against shear stress. But the extrudate swell of the blends showed a strong temperature dependence at each shear stress. The concentration dependence of extrudate swell shows a contrary behaviour to that of the inorganic filled system. A reasonable hypothesis based on the relaxation and disorientation of TLCP during flowing in the capillary and exiting was given to explain it. The melt fracture was checked after extrusion from capillary and was discussed.
Studies on the Side Chain Liquid Crystalline Copolymer Containing Nonlinear Optical Groups
XING Pei-xiang, HUANG Zhi-hua, LIU Zhi-qiang, TANG Xin-yi, JIANG Bing-zheng
1998, 14(3): 324-329.
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A new side chain liquid crystalline poly[4-(methacryloxy)hexanoloxy-4′-benzyloxy biphenyl] was synthesized. The phase behavior of the monomer and homopolymer was studied. The monomer shows a smectic B phase, while the homopolymer shows a nematic phase. The nonmesogenic nonlinear optical group was introduced to synthesize a series of side chain liquid crystalline copolymers which also show a nematic phase. Owing to the liquid crystallinity of the copolymer has been the orientational stability improved, down the relax of the orientation slowed and the nonlinear optical properties enhanced.
Synthesis and Characterization of Poly(isoprene-b-butyl methacrylate) Block Copolymer in the Presence of Rare Earth Catalyst
ZHANG Yi-feng, ZHENG Rong-hua, SHEN Zhi-quan, YAO Ke-min, SHEN Lian-fang, YUAN Han-zheng, Keim-W.
1998, 14(3): 330-334.
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)
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Poly(isoprene-b-butyl methacrylate) block copolymer with a high molecular weight was synthesized in the presence of rare earth coordination catalyst [RE(P
204
)
3
-Al(i-Bu)
3
-DBE]. The block copolymer was characterized by means of GPC,IR,DSC,NMR and elemental analysis. The block copolymer prepared has two glass transition temperatures: -75.6 ℃ and 32.2 ℃. The microstructure of the diblock copolymer possessed 96.8% cis-1,4 addition for the isoprene segment and a 70% syndiotacticity for the butyl methacrylate segment.
The Synthesis of a New Type of Liquid Crystal Containing Rare Earth Element Polyoxometalate
HUANG Ru-dan, FEI Bao-li, WANG En-bo, PENG Jun, SHEN En-hong, ZHANG Shu-xia
1998, 14(3): 335-336.
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New Sesquiterpene Lactones from Carpesium Lipskyi
SHI Yan-ping, YANG Chao, JIA Zhong-jian
1998, 14(3): 337-339.
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)
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Enantioselective Transfer Hydrogenation of Aromatic Ketones Catalyzed by New Diaminodiphosphine Ru(Ⅱ) Complexes
XU Pian-pian, GAO Jing-xing, YI Xiao-dong, HUANG You-qing, ZHANG Hui, WAN Hui-lin, TSAI Khi rui, Ikariya Takao
1998, 14(3): 340-343.
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)
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Electrochemical and Spectroelectrochemical Studies on Electrooxidation Reactions of (TPP)Co
Ⅱ
/NO
3
-
System
LIN Xiang-qin, WANG Zhen-xin, LIU Dian-jun
1998, 14(3): 344-347.
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)
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Diastereoselective Syntheses of (+)-α-Cyperone and Its C-10 Epimer
ZOU Ning, CHENG Dong-liang, PAN Xin-fu, CHEN Yao-zu
1998, 14(3): 348-350.
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