Redox non-innocent bis-silylene aluminium complexes with a carborane backbone.

The redox non-innocent bis-silylenyl -carborane ligands [Si(CC)Si] (CC = -CBH, Si = ArC(NBu)Si; Ar = CH, - BuCH), with their particular chelating and electronic properties, have been employed for the synthesis of new donor-stabilized Si → Al complexes, potential precursors to low oxidation state aluminium complexes. Due to the redox non-innocence of the carborane backbone, [AlI ] complexes with three ligand oxidation states were characterized: with neutral and radical anionic - as well as dianionic -CB cores. Reduction at the aluminium center could also be enacted with potassium/naphthalene leading to {K[Si(CC)Si]Al(CH)} derivatives from [1 + 4] cycloaddition reaction. The mechanism of this dearomatization reaction is proposed to occur the formation of transient low oxidation state aluminium intermediates (radicals and/or aluminylenes) that are trapped by naphthalene.