Monomeric alkali metal (Li, Na, K) complexes of bis(iminophosphorano)methanides

The reaction of the bis(iminophosphorano)methane, CH2(Cy2P=NSMe3)(2) (1), w ith methyllithium (even with excess of the latter) gave the monomeric metha nide complex [Li{HC(Cy2P=NSiMe3)(2)-kappaC,kappaN,kappaN'}(OEt2)] (2) in a good yield. The reaction of H2C(Ph2P=NSiMe3)(2) (2) with equimolar equivale nts of NaH or KH in THF solvent yielded monomeric [M{HC(Ph2P-NSiMe3)(2)-kap paN,kappaN'}(THF)(2)] (M = Na, 4; K, 5) with evolution of hydrogen gas. The crystal structures of each complex show the development of a unique coordi nation sphere around each alkali metal. In the lithium complex, 3, the cent ral carbon atom of the ligand is bound to the metal, but such interaction d oes not occur in the case of either the Na, 4, or the K, 5, complexes. Howe ver in the potassium complex, one of the phenyl rings of the ligand is pi - coordinated to the metal.