Abstract
The redox non-innocent bis-silylenyl ortho-carborane ligands [Si(II)(CC(cage))Si(II)] (CC(cage) = o-C(2)B(10)H(10), Si(II) = ArC(N(t)Bu)(2)Si; Ar = C(6)H(5), p- (t) BuC(6)H(4)), with their particular chelating and electronic properties, have been employed for the synthesis of new donor-stabilized Si(II) → Al(III) complexes, potential precursors to low oxidation state aluminium complexes. Due to the redox non-innocence of the carborane backbone, [AlI(2) (+)] complexes with three ligand oxidation states were characterized: with neutral and radical anionic closo- as well as dianionic nido-C(2)B(10) cores. Reduction at the aluminium center could also be enacted with potassium/naphthalene leading to {K[Si(II)(CC(cage))Si(II)]Al(C(10)H(8))} derivatives from [1 + 4] cycloaddition reaction. The mechanism of this dearomatization reaction is proposed to occur via the formation of transient low oxidation state aluminium intermediates (radicals and/or aluminylenes) that are trapped by naphthalene.