Synthesis and Reactions of Aluminum Sulfonamide Alkyls and Hydride

Abstract

Aluminum compounds supported by a sulfonamide ligand are described. Reaction of AlEt3 with 1 equiv of the sulfonyl amine ArNH(SO2-p-Tol) (Ar = 2,6-iPr2C6H3, Tol = 4-MeC6H4) yielded the dimeric aluminum species [ArN(SO2-p-Tol)AlEt2]2 (1), and reactions of AlEt3 and AlH3·NMe3 with 2 equiv of ArNH(SO2-p-Tol) yielded the aluminum bis(sulfonamide) species [ArN(SO2-p-Tol)]2AlEt (2) and [ArN(SO2-p-Tol)]2AlH (3). The iodide species [ArN(SO2-p-Tol)AlI2]2 (4) and [ArN(SO2-p-Tol)]2AlI (5) were prepared by the reaction of 1 and 2 with iodine. Reaction of 3 with PhNH2, HCCPh, and Ph2CO yielded [ArN(SO2-p-Tol)]2AlNHPh (6), [ArN(SO2-p-Tol)]2AlCCPh (7), and [ArN(SO2-p-Tol)]2AlOCHPh2 (8). Treatment of 6 with BunLi in n-hexane led to a ligand transfer reaction to give the dimeric lithium salt [ArN(SO2-p-Tol)Li(THF)2]2 (9). Compounds 1−4 and 7−9 have been characterized by X-ray single-crystal analysis, which disclosed that the aluminum mono(sulfonamide) compounds adopt a dimeric NSOAlNSOAl eight-membered-ring structure while the aluminum bis(sulfonamide) species are monomeric species with a five-coordinate aluminum center. Interestingly, the lithium salt 9 has a dimeric structure with an OSOLiOSOLi eight-membered-ring core. Compounds 3 and 8 are found to be active for lactide polymerization at high temperature