Synthesis of Some 4-Aryl Substituted Poly(alkyl/arylphosphazenes)

A series of 4-aryl substituted poly(alkyl/arylphosphazenes), [N=P(Me)(p-C6H4–X]n (X = Br, Cl, OMe, CF3), were prepared via the thermal condensation polymerization of the corresponding N-silylphosphoranimines, Me3SiN=P(Me)(p-C6H4–X)–OR (R = CH2CF3, Ph). The new polymers were obtained in high yields and characterized by NMR spectroscopy and molecular weight measurements. Treatment of some of the same Si–N=P precursors with trifluoroethanol afforded the non-geminally substituted cyclic trimers, [N=P(Me)(p-C6H4–X]3 (X = OMe, CF3) as mixtures of cis and trans isomers. The pure cis isomer of the methoxy derivative was isolated and structurally characterized by X-ray diffraction.