Reactions of P-donor ligands with N-silyl(halogeno)organophosphoranimines: formation of cations with P-P coordination bonds and poly(alkyl/aryl)phosphazenes at ambient temperature

A series of phosphine donor-stabilized N-silylphosphoranimine salts [R'3P·PR2=NSiMe3]+Br- were prepared from the direct reaction between the phosphoranimines BrR2P=NSiMe3 (R = Me, OCH2CF3) and the tertiary phosphines nBu3P and Me3P. The 1JPP values of these salts exhibit an unusual dependence on the substituents at the phosphoranimine acceptor and appear to reflect an electronic push-pull mechanism. Employment of phosphites as the phosphorus donor results in the generation of high molecular weight poly(alkyl/aryl)phosphazenes at ambient temperature. This preparative route is potentially advantageous over the conventional thermal polycondensation route.