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The present paper employed density function theory to investigate two reaction pathways for isomerization of enol ester proposed by Yang(path a) and the present authors(path a), respectively. The base catalytic effects of solvent triethylamine on these two reactions were also evaluated. It is demonstrated that path B is more preferable than path a due to low barrier height for the rate-determining step. 相似文献
53.
本文用DSC技术研究了物理老化对PEK-C、PES-C及其共混物和复合材料玻璃化转变的影响.老化时间(t)延长,玻璃化转变温度(Tg)、热焓松弛峰温(Tmax)、峰高(△Cpmax)和热焓(△H)提高;△H与lgt成线性关系.碳黑或碳纤维对PES-C的物理老化行为无影响,而反应性乙炔端基砜(ATS)固化物能限制PEK-C和PES-C在T_g以下温度的物理老化过程.利用物理老化能更为方便地判断多相体系的相容性,结果表明PEK-C/PSF为相容体系,而PEK-C/PES-C相容性较差. 相似文献
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A new complex [Ni(en)3]4[HVⅣ12VⅤ6O42(PO4)] has been hydrothermally synthesized and characterized by X-Ray diffraction, IR and Elemental analysis. Single crystal X-ray analysis indicates that this compoud crystallizes in cubic system,space group Im 3m with a=17.4081(2)?, V=5275.38(10)?3, R=0.0420, wR=0.1055, Z=2, Dc=1.663g·cm-3, μ=2.297mm-1, F(000)=2636. The crystal structure consists of [Ni(en)3]2+ cations and {HV18O42(PO4)}8- cluster anion which construct from 18 {VO5} square pyramids. The VO5 pyramids joined each other to form a {V18O42} cage hosting a tetrahedral {PO4}3- moiety with disordered oxygen atoms. CCDC: 185574. 相似文献
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Two new complexes (Cp)2Ti(Sal)2 and(Cp)2Ti(Clo)2(Cp=Cyclopentadienyl η5-C5H5), have been synthesized in anhydrous THF by the reaction of Hsal(o-hydroxybenzoic acid, salicylate acid) or Hclo[N-(m-chloro-phe-nyl) anthranili acid, acidum clofenamicum] with (Cp)2TiCl2 and characterized by means of elemental analyses, IR, 1H NMR, 13C NMR, UV and molar conductivity. In complex (Cp)2Ti(Sal)2 or (Cp)2Ti(Clo)2, the oxygen atom of the carboxyl group coordinates to Ti(IV) in a monodentate manner. The inhibitory action of the complexes on mouse ear tumefaction caused by croton oil and rat foot granulation growth caused by cotton balls is higher than that of the corresponding ligands Hsal, Hclo and [(Cp)2TiCl2], whereas their toxicity is lower than those of the free ligands. 相似文献
58.
He Ping ZENG 《中国化学快报》2002,13(12)
Photoinduced electron transfer processes between fullerenes (C60 / C70) and N, N, N′, N′- tetra - ( p-methylphenyl ) - 4, 4′- diamino - 1, 1′- diphenyl ether ( TPDAE ) have been studied by nanosecond laser flash photolysis. Quantum yields and rate constants of electron transfer from TPDAE to excited triplet state of fullerenes (C60 / C70 ) in benzonitrile have been evaluated by observing the transient absorption bands in the near-IR region where the excited triplet state, radical anion of fullerenes ( C60 / C70 ) and radical cations of TPDAE appear. 相似文献
59.
Novel macrocyclic monooxa-diselkylene-1,ω-dioxy substituted calix[4]arene derivatives 1a-5a were synthesized by the reaction of calix[4]arene dibromides 1-5 with the disodium salt of bis(2-selenylethyl)ether in the yields between 28% and 64%. Their structures were characterized by proton and carbon NMR spectra. X-Ray structure analysis of la further confirmed the cone conformation of compounds 1a-5a. An interesting host-guest complex of la with dichloromethane via CH/π and C1/π interactions was elucidated. Extraction experiments showed that these novel monooxa-diselkylene-1,ω-dioxy substituted calix[4]arene derivatives 1a-5a had strong extraction ability towards mercury ion. The interaction of Hg^2+with the calix ligand has also been investigated by 1^H NMR titration. 相似文献
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