DIIMINOPHOSPHINATES OF LITHIUM, SAMARIUM AND YTTERBIUM - MOLECULAR-STRUCTURES LI[PH2P(NSIME3)2](THF)2 AND [PH2P(NSIME3)2]2SM(MU-I)2LI(THF)2

The molecular structure of Li[Ph2P(NSiMe3)2]THF)2 (2) has been determined by an X-ray diffraction study. A four-membered LiNPN ring forms the central unit of the monomeric molecule. YbI2 reacts with two equivalents of Li[Ph2P(NSiMe3)2] (1) to give the novel ytterbium(II)diiminophosphinate [Ph2P(NSiMe3)2]2Yb(THF)2 (3). A similar reaction of 1 with SmI2 affords the samarium(III) derivative [Ph2P(NSiMe3)2]2Sm(mu-1)2Li(THF)2 (4) whose structure has also been determined by an X-ray diffraction study.