Neutral six-coordinate fluoro-phosphorus compounds

Three new six-coordinate trifluoromethylfluorophosphorus carbamates F4-n(CF3)nPO2CN(CH3)2 (n = 1, 2, 3) have been prepared by reaction of trimethylsilylcarbamate with the appropriate fluorophosphorane. All products appear to be six-coordinate as indicated by characteristic high field 31P nmr chemical shifts and in some cases are fluxional. Two isomers are observed in the nmr spectra of the compound with n = 1. Only one structure is formed in the n = 2 and 3 cases. The crystal and molecular structure of F(CF3)3PO2CN(CH3)2 revealed a six-coordinate structure with the unique F in the plane containing the chelated carbamate.