A topological Hückel model for organometallic complexes. Part I. Bond lengths in complexes of conjugated olefins

Abstract

A simplified molecular-orbital (m.o.) model is developed which accounts simply for the bond lengths of a wide range of metal η⁴-olefin complexes. The calculations reproduce the two most important geometric features associated with metal η⁴-polyene complexes, i.e. the relative insensitivity of the carbon–carbon bond lengths of the co-ordinated butadiene moiety to the number of phenyl rings fused to it and the fixation of one double bond in the phenyl ring which is adjacent to the butadiene moiety.