HAlCl2 and H2AlCl as Precursors for the Preparation of Compounds with Four- and Five-Coordinate Aluminum

Carbenes are known as donor molecules to form with chloroalane adducts, which enhances their aerobic and thermal stabilities. In contrast, the insertion products (cAACH)AlCl2(cAAC) (1) and (cAACH)AlHCl(THF) (2; THF = tetrahydrofuran) have been formed in the reaction of a cyclic alkyl(amino)carbene (cAAC:) with HAlCl2, and H2AlCl, respectively. PhC(NtBu)2Li as the precursor for the reaction with HAlCl2 in a molar ratio of 2:1 can easily form compound [PhC(NtBu)2]2AlH (3) with five-coordinate aluminum. The new products have been studied by spectroscopic methods and single-crystal X-ray diffraction.