Synthesis and reactions of 1-t-butyldimethylsilyl-2,3-diphenyl-1-aza-3-phosphaallyl lithium and potassium. Crystal structures of [M{P(Ph)C(Ph)NSiMe2But}(L)]2 (M=Li, L=THF; M=K, L=Et2O), [Sn{P(Ph)C(Ph)NSiMe2But}2] and [P(Ph)C(Ph)NSiMe2But]2

Reaction of MP(Ph)SiMe2But (M=Li, K) with an equivalent of PhCN afforded the 1-aza-3-phosphaallyllithium and -potassium complexes [SiMe2But}(L)]2 (1, M=Li, L=THF; 2, M=K, L=Et2O), respectively. After exposing 2 in vacuo at room temperature, the solvent-free complex [SiMe2But}] (3) was obtained. Treatment of 1 with SnCl2 in a 2:1 ratio furnished the homoleptic tin(II) complex [SiMe2But}2] (4). Compound 1 reacted with an equimolar amount of ClSnN(SiMe3)2 to give [P(Ph)C(Ph)NSiMe2But]2 (5) via ligand coupling. Reaction of 3 with PhCN produced [K{P(Ph)C(Ph)NC(Ph)NSiMe2But}] (6) by addition of the nitrogen atom to PhCN followed by a 1,3-N→N′ migration of the SiMe2But group. Structures of compounds 1, 2, 4 and 5 have been determined by single crystal X-ray diffraction techniques. The complexes 1 and 2 are dimeric and 4 is both monomeric, while 5 is the product of a ligand coupling with formation of new PP bond.