Theoretical Studies on Electronic Spectra and Second-order Nonlinear Optical Properties of Barbituric Acid Derivatives Substituted with Schiff Base  

作　　者：孙刚 仇永清 孙海珠 苏忠民 冯静东 朱玉兰 

机构地区：[1]Institute of Functional Material Chemistry, Faculty of Chemistry, Northeast Normal University, Changchun, Jilin 130024, China [2]State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun, Jilin 130023, China [3]Department of Chemistry, Science and Engineering College, Yanbian University, Yanji, Jilin 133002, China

出　　处：《Chinese Journal of Chemistry》2004年第5期425-429,共5页中国化学（英文版）

基　　金：Project supported by the National Natural Science Foundation of China (No. 20162005) and Trans-century Programme Foundation for the Talents by the State Education Commission; China (No. [2001]3).

摘　　要：The structures of barbituric acid derivatives substituted with Schiff base were optimized using ab initio HF method at 6-31G basis set. Based on the optimized structures, the electronic spectra were obtained by INDO/CI method. The second-order nonlinear optical (NLO) coefficients βμ were calculated according to the sum-over-states (SOS) formula. In addition, the effect of conjugation on electronic specra and second-order NLO coefficients was investigated. The influence of exchange between C and N atoms as well as the substituted effect on the barbituric acid was discussed. It was indicated that the exchange between C and N atoms on Schiff base is important for enhancing the NLO coefficient of the whole molecule with donor and acceptor (D-A). Meanwhile significant changes in electron donation and acception were observed as substituents changes positions. Among the designed models, molecule lb has maximal βμ value of 124.65×10?-30 esu. About molecule lb, barbituric acid is considered as an accepted electronic group and the position of N atom on Schiff base is close to it.The structures of barbituric acid derivatives substituted with Schiff base were optimized using ab initio HF method at 6-31G basis set. Based on the optimized structures, the electronic spectra were obtained by INDO/CI method. The second-order nonlinear optical (NLO) coefficients βμ were calculated according to the sum-over-states (SOS) formula. In addition, the effect of conjugation on electronic specra and second-order NLO coefficients was investigated. The influence of exchange between C and N atoms as well as the substituted effect on the barbituric acid was discussed. It was indicated that the exchange between C and N atoms on Schiff base is important for enhancing the NLO coefficient of the whole molecule with donor and acceptor (D-A). Meanwhile significant changes in electron donation and acception were observed as substituents changes positions. Among the designed models, molecule lb has maximal βμ value of 124.65×10?-30 esu. About molecule lb, barbituric acid is considered as an accepted electronic group and the position of N atom on Schiff base is close to it.

关 键 词：INDO/CI NLO electronic spectra 

分 类 号：O621[理学—有机化学]