SYNTHESIS OF OPEN-CHAIN POLY(DIFLUOROPHOSPHAZENE) AND ITS REACTIONS WITH ALKOXIDES, ARYLOXIDES, AND AMINES

The first synthesis of a soluble form of high molecular weight poly(difluorophosphazene), (NPF2)n, has been carried out, and the reactions of this polymer with amines, alkoxides, or aryloxides have been examined. Poly(difluorophosphazene) reacted smoothly with sodium trifluoroethoxide to yield high molecular weight [NP(OCH2CF3)2]n. However, reactions with amines, such as methylamine, n-butylamine, dimethylamine, or aniline, resulted in some chain cleavage and in the formation of nongeminal, partly substituted products of the general formula [NPF(NHR)]n. The limited chain cleavage was ascribed partly to hydrogen fluoride attack on the polymer backbone and also to subsequent hydrolysis of residual P-F bonds. Comparisons with the chemistry of poly(dichlorophosphazene), (NPCl2)n, indicate fundamental differences between the substitution chemistry of the fluoro- and chlorophosphazene systems, and explanations for these differences are suggested. From a synthetic viewpoint, the unusual reactivity of (NPF2)n provides reaction routes to stable new poly(organophosphazenes), such as [NP(NHC4H9)(OCH2CF3)]n, that are not accessible through (NPC12)n. © 1979, American Chemical Society. All rights reserved.