Advances in the chemistry of Lewis base-adducts of alane and gallane

Tertiary amine adducts of alane show a diverse range of structures based on four and five coordinate species, hydride bridging dimeric and polymeric species, and ionic species, whereas those of gallane are usually restricted to four coordinate species. Phosphine adducts of alane are four or five coordinate, and four coordinate for gallane. Stable, volatile adducts of both alane and gallane are available. Mixed donor adducts of alane are accessible, such as those based on N-alkylmorpholine, and these have relevance in the binding of [H3AlNMe3] to oxidised surfaces. Alane metallates secondary amines, bulky amines excepted which can yield stable amine adducts; secondary amines based on N,N'-disubstituted ethylenediamine give a range of products depending on the nature of the alane, the use of [H2AlNMe3] is complicated by its tendency to form less reactive [H3Al(NMe3)(2)]. The tricyclohexylphosphine adduct of monochlorogallane is a useful precursor for forming the phosphidogallium species [{H2Ga(mu-PCy2)}(3)] via reaction with [Li(PCy2)(THF)(n)]. Reaction of [H3AlNMe3] with p-Bu-t-calix[4]arene and its dimethyl ether afford respectively a divergent receptor bis-calixarene species and a monocalixarene species with a residual hydride either endo-or exo- to the calixarene cavity. Lewis base adducts of alane and gallane show promise in functional group chemistry with gallane behaving as a milder, more selective reducing agent. Reactions of (ER)(2), E = Se or Te, R = alkyl or aryl, with [H3MNMe3], M = Al or Ga, afford trimethylamine adducts of the tris(selenolato- or tellurolato-)metal(III) species, [Me3NM(ER)(3)], and reactions of elemental Se or Te with [H3AlNMe3] afford the mixed chalcogenide/hydridetrans-[{Me3N(H)Al(mu-E)}(2)]. (C) 1997 Elsevier Science S.A.