Lithio-di-t-butylfluorsilylphenylphosphan; im Kristall ein (SiFLiP)2-Achtring

Di-t-butylfluorosilylphenylphosphane (I) reacts with CMe3Li to give the lithium compound [(CMe3)2SiFLi(THF)2PC6H5]2 (II) and butane. The crystal structure of II has been determined. The SiP bond length (217.1 pm) in the eight-membered ring is extremely short. The SiP spin coupling constant (84.12 Hz) in II is remarkably large. LiF elimination from II leads to the formation of the four-membered (SiP) ring III. The bis(fluorosilyl)phosphane IV is formed in the reaction of II with Me2SiF2.