Reactions of <i>N</i>-Silylphosphoranimines with Alcohols: Synthesis and Structure of Cyclotriphosphazenes with Nongeminal Methyl and Phenyl Substituents

The reactions of Me3SiNP(OR‘ ‘)RR‘ (R‘ ‘ = Ph, CH2CF3; R, R‘ = Me, Ph) with alcohols were investigated. With nonequivalent amounts of CF3CH2OH, the reactions produced high yields of the cyclic phosphazene (Me2PN)3 and both the cis and trans isomers of nongeminally substituted [(Ph)(Me)PN]3. The isomers of this new cyclic phosphazene were separated by column chromatography and characterized by NMR and IR spectroscopy, elemental analysis, and X-ray crystallography. Crystals of the cis isomer 6a have a monoclinic crystal system, while the trans isomer 6b has a triclinic crystal system with two different molecules in an asymmetric unit. The bond lengths and bond angles are very similar to those of the simpler cyclic trimers (Me2PN)3 and (Ph2PN)3. A likely pathway for the formation of these compounds is discussed.