Synthesis, Characterization, and Computational Analysis of the Dialanate Dianion, [H3 Al-AlH3 ]2- : A Valence Isoelectronic Analogue of Ethane.

The first example of a well-defined binary, low-oxidation-state aluminum hydride species that is stable at ambient temperature, namely the dianion in [{(Dep Nacnac)Mg}2 (μ-H)]2 [H3 Al-AlH3 ] (Dep Nacnac=[(DepNCMe)2 CH]- , Dep=2,6-diethylphenyl), has been prepared via a magnesium(I) reduction of the alanate complex, (Dep Nacnac)Mg(μ-H)3 AlH(NEt3 ). An X-ray crystallographic analysis has shown the compound to be a contact ion complex, which computational studies have revealed to be the source of the stability of the aluminum(II) dianion.