Ferrocenyl(dimethyl)aluminum dimer [(η5-C5H5)Fe(η5-C5H4)AlMe2]2

The reaction of ferrocenyllithium (FcLi, 1) with dimethyl or diethylaluminum chloride affords known mixed dimers 2 built from dialkyl(ferrocenyl))aluminium and dialkylaluminum chloride and also, depending on the reaction conditions, the unknown dimers from dialkyl(ferrocenyl)aluminum 3, of which the dimethyl derivative could be isolated in a pure state and characterised by X-ray structural analysis. The ferrocenyl group occupies the bridging position and there is a centre of inversion. The solution-state structures were determined by NMR spectroscopic methods (1H, 13C, 27Al NMR). The gas-phase structure of monomer FcAlH2 3(M) was optimised at the B3LYP/6-311 + G(d,p) level of theory.