CHALCOGENIDES OF ALUMINUM(III) AND GALLIUM(III) DERIVED FROM LEWIS BASE ADDUCTS OF ALANE AND GALLANE

Reductive cleavage of (ER)(2) by [GaH3L], L = NMe3 or P(C6H11)(3), aff orded [Ga(TePh)(3)(NMe3)], [Ga(SeEt)(3)-(NMe3)] and [Ga(TePh)(3){P(C6H 11)(3)}]; the latter was also prepared by the reaction of [GaH2Cl{P(C6 H11)(3)}] with LiTePh. They have slightly disordered tetrahedral metal centres, established in the solid for [Ga(TePh)(3)(NMe3)] and [Ga(TeP h)(3){P(C6H11)(3)}], and in the structure of the aluminium analogue, [ Al(SePh)(3)(NMe3)], which was also determined. Reaction of [GaH2Cl{P(C 6H11)(3)}] with Li2Se afforded dinuclear trans-[{GaCl(mu-Se)[P(C6H11)( 3)]}(2)] (minor product) which is centrosymmetric with distorted tetra hedral metal centres associated with a planar Ga2Se2 ring system. Trea tment of trans-[{AlH(mu-Se)(NMe3)}(2)] with tmen (=N,N,N',N'-tetrameth ylethane-1,2-diamine), or [{AlH3(tmen)}(infinity)] with elemental sele nium, afforded polymeric [{[AlH(mu-Se)](2)(tmen)}(infinity)]. Cleavage of (EPh)(2) by trans-[{AlH(mu-Se)(NMe3)}(2)] gave trans-[{Al(mu-Se)(E Ph)(NMe3)}(2)], E = S, Se or Te, also as centrosymmetric dinuclear spe cies with planar Al2Se2 ring systems. Reaction of trans-[{AlH(mu-Se)(N Me3)}(2)] with 2 equivalents of NH(SiMe3)(2) or 6-methyl-2-trimethylsi lylaminopyridine gave the secondary amine metallated products trans-[{ Al(mu-Se)[N(SiMe3)(2)](NMe3)}(2)] (structurally authenticated as a cen trosymmetric dinuclear species) and [{Al(mu-Se)(NC5H3NSiMe3-2-Me-6)}(2 )].