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.