σ-Alane Complexes of Chromium, Tungsten, and Manganese

Photolytic ligand displacement and salt metathesis routes have been exploited to give access to kappa(1) sigma-alane complexes featuring Al-H bonds bound to [W(CO)(5)] and [Cp'Mn(CO)(2)] fragments, together with a related kappa(2) complex of [Cr(CO)(4)]. Spectroscopic, crystallographic, and quantum chemical studies are consistent with the alane ligands acting predominantly as sigma-donors, with the resulting binding energies calculated to be marginally greater than those found for related dihydrogen complexes.