An ab initio M. O. study of 7-silanorbornadiene and 7,7-dimethyl-7-silanorbornadiene; examples of norbornadienes in which the ? orbitals interact largely through-bonds rather than through-space

Abstract

It has been found that the π M.O.s of the fully optimized title molecules (HF/3-21G, C_2v symmetry constraint) follow an inverted sequence [i.e. the π₊(a₁) level lies above the π_–(b₁) level]; a Natural Bond Orbital (N.B.O.) analysis reveals the origin of this inverted sequence.