Formation of a diazadiphosphetidine from the reactions of a bis(aminosilyl) ether with PCl3: crystal structure of cis-[(ButNH)PNBut]2

Abstract

Reaction of O[SiMe ₂ N(Bu ^t )H] ₂ 1 with PCl ₃ in 1∶1 molar ratio in hexane in presence of NEt ₃ gave the cyclic four-membered diazadiphosphetidine cis-[(Bu ^t NH)PNBu ^t ] ₂ 2 instead of the expected six-membered silazoxyphosphine indicating cleavage of the Si–N bond. A crystal structure analysis of 2 showed that the NH hydrogens of the Bu ^t NH groups are in an endo-endo orientation above the (PN) ₂ ring which is in contrast to the exo-endo orientation for the known structure of its disulfide.