ADVANCES IN THE CHEMISTRY OF LEWIS BASE-ADDUCTS OF ALANE AND GALLANE

Tertiary amine adducts of alane show a diverse range of structures bas ed on four and five coordinate species, hydride bridging dimeric and p olymeric species, and ionic species, whereas those of gallane are usua lly 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-alkylmorphol ine, and these have relevance in the binding of [H3AlNMe3] to oxidised surfaces. Alane metallates secondary amines, bulky amines excepted wh ich can yield stable amine adducts; secondary amines based on N,N'-dis ubstituted ethylenediamine give a range of products depending on the n ature of the alane, the use of [H2AlNMe3] is complicated by its tenden cy to form less reactive [H3Al(NMe3)(2)]. The tricyclohexylphosphine a dduct of monochlorogallane is a useful precursor for forming the phosp hidogallium species [{H2Ga(mu-PCy2)}(3)] via reaction with [Li(PCy2)(T HF)(n)]. Reaction of [H3AlNMe3] with p-Bu-t-calix[4]arene and its dime thyl ether afford respectively a divergent receptor bis-calixarene spe cies and a monocalixarene species with a residual hydride either endo- or exo- to the calixarene cavity. Lewis base adducts of alane and gall ane show promise in functional group chemistry with gallane behaving a s a milder, more selective reducing agent. Reactions of (ER)(2), E = S e or Te, R = alkyl or aryl, with [H3MNMe3], M = Al or Ga, afford trime thylamine adducts of the tris(selenolato- or tellurolato-)metal(III) s pecies, [Me3NM(ER)(3)], and reactions of elemental Se or Te with [H3Al NMe3] afford the mixed chalcogenide/hydridetrans-[{Me3N(H)Al(mu-E)}(2) ]. (C) 1997 Elsevier Science S.A.