Si—Si键传递取代基效应的量子化学研究

A QUANTUM CHEMICAL STUDY ON THE ABILITY OF PROPAGATING THE EFFECT OF STUBSTITUENT GROUPS BY SI-SI BOND

在有机化学领域中,已经广泛开展了对C—C键传递取代基效应的研究,找到了解释静电效应及空间效应的一把钥匙。但至今只有少数人讨论了Si—Si键对取代基效应的传递。1982年,Yoder等用NMR对C—C键和Si—Si键传递取代基效应的能力进行了对比研究,测定了XSi（CH3）2Si（CH3）3（X=F,Cl,CH3等）的化学位移及耦合常数,并由此论证了Si—Si键传递取代基的能力比C—C键弱得多的原因。

This paper has calculated several series of molecules with general formulas XMH_2MH_3, X_1MH_2MH_2CH_3 and XM(CH_3)_2M(CH_3)_3 [where X=F, Cl,H,CH_3; M=C or Si] by means of INDO, MNDO(with energy gradient to optimize the equilibrium geoxnetry of molecules)and MPCILO methods. The results of calculation are used to study the ability of propagating the effect of substituent groups by Si-Si bond comparad to C-C bond from points view of molecular orbital theory and bond orbital theory.