TRANSMETALATION REACTIONS OF STERICALLY ENCUMBERED GALLIUM AND INDIUMHALIDES WITH TETRAHYDROMETALATES - SYNTHESIS AND STRUCTURE OF A BASE-FREE MONOMERIC ALUMINUM-HYDRIDE

The reaction of(Ar)(2)GaCl or (Ar*)(2)InCl (Ar* = 2,4,6-t-Bu(3)C(6)H( 2)) with LiAlH4 resulted in transmetalation and formation of (Ar)(2)A lH (6), the first example of a structurally authenticated monomeric ba se-free aluminum hydride. An. X-ray crystallographic study revealed th at the monomeric nature of the new hydride is due to the shielding of the AI-H moiety by o-t-Bu groups of the aryl ligands. Crystal data for 6: space group P2(1)/c, a = 10.024(2) Angstrom, b = 29.745(4) Angstro m, c = 11.459(1) Angstrom, beta = 94.87(1)degrees, V = 3404(2) Angstro m(3), Z = 4. The X-ray crystal structure of (Ar)(2)InCl (5) has also been determined. Crystal data for 5: space group P2(1)/c, a = 10.328(2 ) Angstrom, b = 22.924(2) Angstrom, c = 16.091(1) Angstrom, beta = 107 .34(1)degrees, V = 3636.6(8) Angstrom(3), Z = 4.