有机磷化合物的研究 72.含磷非对映异构体^(31)P NMR结构效应的分子力学研究  

Studies on Organophosphorus Compounds 72. A Molecular Mechanics Study of the Structure Effect of Phosphorusbased Diastereoisomers on the ^(31)P NMR Chemical Shift

作　　者：李树森[1] 王国权[1] 李耀和 李英 袁承业[1] 

机构地区：[1]中国科学院上海有机化学研究所,上海200032

出　　处：《化学学报》1993年第12期1195-1202,共8页Acta Chimica Sinica

基　　金：国家自然科学基金和中国科学院计算机化学开放实验室资助的课题.

摘　　要：本文通过两组含磷非对映异构体^(31)p NMR化学位移的测定和分子力学计算,观察到非对映异构体之间,分子力学计算的磷原子局部Van der Waals相互作用能(E_(VDW-P))是影响其^(31)p NMR化学位移的主要因素,即E_(VDW-P)大的异构体,δ_(31P)在低场;E_(VDW-P)小的,δ_(31P)在高场。这一结果对利用非对映异构体中某核的NMR化学位移的实验测定,结合分子力学计算的该核的局部Van der Waals相互作用能。建立一种简便的确定非对映异构体中未知不对称中心的绝对构型的新方法,具有一定的理论意义和实用价值。The structural influence of two series of phosphorus-based diastereoisomers on the ^(81)P NMR chemical shift is evaluated by molecular mechanics calculation. The results reveal that the intramolecular local Van der Waals inceraction energy of phosphorus atom (E_(VDW-P)) calculated by MM2(85) program is the predominating factor governing the magnicude of the chemical shift of the phosphorus nucleus. The isomer, which has relative large E_(VDW-P) value will show downfield ^(31)P NMR chemical shift or vice versa. This empirical approach provides the experimental basis of a new and facile method for the elucidation of the absolute configuration of diastereoisomers with any asymmetric center. It has, therefore, siganificant theoretical importance and potential practical value.

关 键 词：NMR 分子力学 有机磷化合物 磷31 

分 类 号：O627.51[理学—有机化学]