Synthesis and reactions of 1-t-butyldimethylsilyl-2,3-diphenyl-1-aza-3-phosphaallyl lithium and potassium. Crystal structures of [ SiMe2Bu }(L)]2 (M=Li, L=THF; M=K, L=Et2O), [ SiMe2Bu }2] and [P(Ph)C(Ph)NSiMe2Bu ]2

Reaction of MP(Ph)SiMe 2 Bu t (M=Li, K) with an equivalent of PhCN afforded the 1-aza-3-phosphaallyllithium and -potassium complexes [ SiMe 2 Bu t }(L)] 2 ( 1 , M=Li, L=THF; 2 , M=K, L=Et 2 O), respectively. After exposing 2 in vacuo at room temperature, the solvent-free complex [ SiMe 2 Bu t }] ( 3 ) was obtained. Treatment of 1 with SnCl 2 in a 2:1 ratio furnished the homoleptic tin(II) complex [ SiMe 2 Bu t } 2 ] ( 4 ). Compound 1 reacted with an equimolar amount of ClSnN(SiMe 3 ) 2 to give [P(Ph)C(Ph)NSiMe 2 Bu t ] 2 ( 5 ) via ligand coupling. Reaction of 3 with PhCN produced [K{P(Ph)C(Ph)NC(Ph)NSiMe 2 Bu t }] ( 6 ) by addition of the nitrogen atom to PhCN followed by a 1,3-N→N′ migration of the SiMe 2 Bu t 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.