Theoretical study of the oxidative addition of 16-electron d(4) [n]-metallocenophane complexes with methane

We have chosen eight [n]-metallocenophane complexes to investigate the oxid ative additions with methane using the B3LYP/LANL2DZ level of theory. Consi dering the effects from the geometry and the nature of the metal center, th e following conclusions emerge: the less bent 16-electron [n]-metallocenoph ane complex with the transition metal center W should be a potential model for the oxidative addition of saturated C-H bonds. Our model calculations s uggest that a methane sigma -complex intermediate formed between the [n]-me tallocenophane and methane plays a major role in the oxidative additions. M oreover, we show that both electronic and geometric effects play a signific ant role in determining the energy barriers.