Premium
Theoretical studies on electronic spectra and second‐order nonlinear optical properties of barbituric acid derivatives substituted with schiff base
Author(s) -
Sun Gang,
Qiu YongQing,
Sun HaiZhu,
Su ZhongMin,
Feng JingDong,
Zhu YuLan
Publication year - 2004
Publication title -
chinese journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 41
eISSN - 1614-7065
pISSN - 1001-604X
DOI - 10.1002/cjoc.20040220506
Subject(s) - chemistry , barbituric acid , schiff base , molecule , acceptor , computational chemistry , base (topology) , ab initio , atom (system on chip) , ab initio quantum chemistry methods , crystallography , organic chemistry , mathematical analysis , physics , mathematics , computer science , embedded system , condensed matter physics
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.