Das Tricarbonyl-eisen-cycloheptatrienid-Anion [C7H7Fe(CO)3]–: η3-Allylanion- oder η4-Butadienkomplex? / The Triearbonyl Iron Cyeloheptatrienide Anion: η3-Allyl Anion or η4-Butadiene Complex?

Abstract

Abstract Molecular orbital calculations for [C7H7Fe(CO)3]-predict a η3 -allyl anion Fe(CO)3 complex with un-coordinated diene part of the C7H7 ligand to be more stable than the alter-native η4 -butadiene Fe(CO)3 form, the cyclopolyenyl ligand being nonplanar in either case. The tiny energy difference between both coordination modes accounts for the observed high fluxionality of the anion.