REACTIVITY OF R(2)ALH (R=ME, BU(I)) WITH SELECTED AMINOARSINES AND SECONDARY-AMINES

Me(2)AlH and Bu(2)(i)AlH were reacted with a series of nine aminoarsin es, Me(2)AsR (R = NMe(2), NPr(n)2, NPr(i)2, NBu(n)2, NBu(i)2, NC4H8, N C5H10, NC6H12, and N(C2H4)(2)NMe), in C6D6 at room temperature, and th e reactions were monitored by H-1 and C-13 NMR spectroscopy. The relat ive rates for initial As-N bond cleavage and final product formation w ere dependent on the steric requirements of the alkyl groups attached to aluminum and nitrogen in the starting materials. Overall rates were slower with Bu(2)(i)AlH than with Me(2)AlH for a given aminoarsine. F or most of the reactions, the predominant Al-containing products were the dimeric aminoalane compounds, [Me(2)AlR](2) and [Bu(2)(i)AlR](2). Although AI-N bond formation was the prefered mode of reaction, Al-As bond formation was also observed when the bulky Pr-i and Bu(i) aminoar sine derivatives were used. The [Bu(2)(i)A1R](2) compounds were synthe sized independently by the reaction of Bu(2)(i)AlH and the respective amine or, in the case of [Bu(2)(i)AlBu(2)(i)](2), by the reaction of B u(2)(i)AlCl and LiNBu(2)(i). X-ray crystal structures were determined for the compounds [Me(2)AlNC(6)H(12)](2), [Me(2)AlN(C2H4)(2)NMe](2), [ BU(2)(i)AlNMe(2)](2), and [Bd(2)(i)AlN-(C2H4)(2)NMe](2). All of the co mpounds have planar Al2N2 rings with the exception of [Bu(2)(i)AlN(C2H 4)2NMe](2), which displays a puckered Al2N2 ring.