Interaction of the bulky alane (H2AlC6H3-2,6-Mes2)2 (Mes=–C6H3-2,4,6-Me3) with H2EPh (E=N, P or As)

Abstract

The reactions of the bulky primary alane (H2AlC6H3-2,6-Mes2)2 (Mes=–C6H2-2,4,6-Me3) with H2EPh (E=N, P or As) are described. With aniline, H2NPh, the dimeric products 2,6-Mes2H3C6{Ph(H)N}Al{µ-N(H)Ph}2Al(H)C6H3-2,6-Mes2 (1) and [2,6-Mes2H3C6(H)Al{µ-N(H)Ph}]2 (2) are obtained. The structures of both 1 and 2 feature two –C6H3-2,6-Mes2 substituted aluminums bridged by two –N(H)Ph groups. In 2 each aluminum is also bound to a terminal hydrogen whereas in 1 one of these hydrogens is replaced by a terminal –N(H)Ph substituent. The structure of the –P(H)Ph derivative [2,6-Mes2H3C6(H)Al{µ-P(H)Ph}]2 (3) is very similar to that of 2 (and presumably the arsenido derivative 4) and features bridging phosphido groups and four-coordinate aluminums. The arsenido dimer 4 is cleaved by ether to give the ether adduct 2,6-Mes2H3C6(H)Al{As(H)Ph}(OEt2) for which a partial X-ray structure was determined. Thermolysis of 2, 3 and 4 led to decomposition. However, heating (H2AlC6H3-2,6-Mes2)2 with excess H2AsPh led to the unique cluster (2,6-Mes2H3C6Al)2{µ-As(H)Ph}2(µ-PhAsAsPh) which has a basket-type Al2As4 core.