硼烷分子中化学键性质的研究 Ⅱ.B_3H_7中四中心键及B_3H_9中三个隔离的氢桥三中心键  

Studies on the Nature of Chemical Bonds in Boranes II . The Four-center Bond in B_3H_7 and the Three Separated Hydrogen Bridged Three-Center Bond in B_3H_9

作　　者：武海顺[1] 潘道皑 周伟良[2] 刘元隆[2] 

机构地区：[1]山西师范大学化学系,临汾041004 [2]华东师范大学化学系,上海200062

出　　处：《化学学报》1996年第7期638-643,共6页Acta Chimica Sinica

基　　金：中国科学院计算机化学开放实验室与山西省自然科学基金资助课题

摘　　要：用Dunning基进行从头计算的结果表明:在B_3H_7(1103)中氢桥三中心键与BBB三中心键间已用σ-共轭效应”融合”为一个四中心键,其特征为f_(B(1)-B(2))=0.1653,f_(B(2)-B(3))=0.1429,f_(B-H_b-B)=0.3416,f_(4center)=0.7193hartree/bohr.但在B_3H_9中三个氢桥三中心键间不相互作用,保持相互独立,其特性为f_(B-B)=0.0558,f_(B-H_b-B)=0.3922,f_(H_b3cen)=0.5115hartree/bohr.As a result of ' ab initio' study, using Dunning's basis set, it is shown that, in (1103), the two three - center bonds have been fused into a four - center bond, owing to the a -conjugation effect. The properties in bond strength of this four- center bond are: fB(1)-B(2) = 0.1653, fB-Hb-B = 0.3416, fB(2)-B(3) = 0.1429, f4center= 0.7193 hartree/bohr.No σ- conjugation effect can take place between the three separated three - centerbonds in B3H9, whose properties are:fB-B= 0.0558, fB-Hb-B = 0.3922, fHb3cen. = 0.5115 hartree/bohr.

关 键 词：硼烷 从头计算 键强参数 多中心键 化学键 

分 类 号：O627.31[理学—有机化学] O641.121[理学—化学]