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Semiempirical prediction of the hyperpolarizabilities for cyanovinyl-substituted donor-acceptor molecules

Chinese Journal of Chemistry 1996年第5期14卷 393-398页

作者： Zhao, CY Zhang, Y Fang, WH You, XZ NANJING UNIV CTR ADV STUDIES SCI & TECHNOL MICROSTRUCTINST COORDINAT CHEMNANJING 210093JIANGSUPEOPLES R CHINA

We present here a systematically theoretical study on the nonlinearities and their structure-property relationship of cyanovinyl-substituted donor-acceptor molecules by virtue of semiempirical pm3/AM1-FF approach. Good consistency between measured and calculated hyperpolarizabilities is obtained. Results show that conformation has a significant effect on hyperpolarizabilities. The torsion angle change between two conjugated parts of the molecular systems can substantially alter the nonlinearities. The total amount of charge transfer difference from donor to acceptor has been introduced to understand the microscopic nature of the nonlinear optical properties for the title molecules. General guidelines may be sought out in the search of molecules with large values of beta. Some molecules with large molecular hyperpolarizabilities can be predicted by the optimization for the longer pi-electron systems with both acceptor and donor groups.

关键词： nonlinear optics hyperpolarizabilities pm3 method cyanovinyl-substituted molecules

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Quantum Chemical Study on the Thermolysis of Dicyanofuroxan

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Chinese Chemical Letters 1998年第2期9卷 187-189页

作者： Li, YH Xu, WY Peng, YY Hong, SG Wang, S Jiangxi Normal Univ Dept Chem Nanchang 330027 Peoples R China Jiangxi Normal Univ Dept Chem Nanchang 330027 Peoples R China

AM1 and pm3 methods using the unrestricted Hartree-Fock (UHF) calculations have been applied to study the thermolysis of dicyanofuroxan. The results obtained show that the reaction proceeds to product through a two-st... 详细信息

关键词： transition state thermolysis dicyanofuroxan AM1 method pm3 method

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Research of Inclusion Complexation of 4,4'-Thiodiphenol Effected by β-Cyclodextrin in Aqueous Solutions and the Effect on Photodegradation

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Wuhan University Journal of Natural Sciences 2007年第3期12卷 535-540页

作者： ZHANG Xu WU Feng WANG Beibei DENG Nansheng LUO Mingdao School of Resource and Environmental Science Wuhan University Wuhan 430079 Hubei China College of Chemistry and Molecular Science Wuhan University Wuhan 430072 Hubei China

The inclusion behavior of 4, 4＇ -Thiodiphenol （TDP）, a typical bisphenol and endocrine disruptor, reacts with β-cyclodextrin （β-CD） in aqueous solutions has been investigated by means of UV absorption spectrum and quantum-chemical calculation with Gaussian 98 software. The results show that the inclusion behavior of TDP is quite different in acidic solutions （pH 5.9） from that in alkaline solutions （pH 10.0）. This behavior difference is attributed to the different formula structures in aqueous solutions at acidic and alkaline pH values that are demonstrated by quantum- chemical modeling and calculation. TDP forms a 1 ： 1 fl-CD inclusion complex in aqueous solutions. The equiiibrium constant K was calculated to be 553.49 L/mol at pH 5.9 and 1 318.20 L/mol at pH 10.0 respectively for the inclusion complex reaction by using the modified Benesi-Heldbrand equation. After inclusion TDP＇s structure is changed especially at the inclusion part with the bond order becoming larger, which results in inhibitive photodegradation during direct photooxidation and H2O2 assisted photooxidation.

关键词： β-cyclodextrin inclusion complex photodegradation pm3 method

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