联吡咯构象异构的理论计算

Theoretical Calculation on Conformation Isomerization of Bipyrrole

构象分析是阐明分子结构的最重要手段之一,理论计算能够给出分子构象异构的一般信息。采用HF/6-31G*、B3LYP/6-31G*、BH&HLYP/6-31G*和MP2/6-31G*方法,对3种联吡咯构造异构体进行了构象分析。采用BH&HLYP/6-31++G**方法进行势能面上稳定点和过渡态的计算。结果表明,气相中6个联吡咯能量极小构象体能量差最大达14.56kJ/mol,转化能垒最大达10.19kJ/mol。采用自洽反应场极化连续模型溶剂理论,探讨了水溶剂对优势构象异构体的几何结构和能量的影响。结果表明,水相中6个联吡咯能量极小构象体的能量差最大达9.40kJ/mol,转化能垒最大达11.68kJ/mol。这种系统化研究有助于理解联吡咯各构造异构体之间构象能量与几何结构的关系。

The conformational analysis of various isomers of bipyrroles was investigated by HF /6-31G*,B3LYP /631G*,BH&HLYP /6-31G* and MP2 /6-31G* method.The conformers located at minima by B3LYP /6-31G* calculation were reoptimized by B3LYP /6-311 + + G method without any constraints.The mechanism of bipyrrole conformational isomerization was studied and the geometric parameters of transition states were located by B3LYP /6-311 + + G.The polarized continuum model(PCM) was employed for aqueous solution calculatio...