Synthesis of Telechelic Polyphosphazenes via the Ambient Temperature Living Cationic Polymerization of Amino Phosphoranimines

A method for the synthesis of well-defined mono-, di-, and mixed-telechelic polyphosphazenes produced via a living cationic polymerization of phosphoranimines is described. Amino phosphoranimines R−NH(CF 3 CH 2 O) 2 P NSiMe 3 (R = Ph−, p -BrPh−, p -H 3 CPh−, CH 2 CHCH 2 −, and CH 2 CHPh−) were synthesized via a reaction between a bromophosphoranimine and the appropriate organic amine. Ditelechelic polymers [R−NH] 2 −[Cl 2 P N] n were prepared by quenching living poly(dichlorophosphazene) chains, [Cl 3 P N(Cl 2 P N) n −PCl 3 ] + [PCl 6 ] - with small quantities of the amino phosphoranimines. Cationic initiators of the amino phosphoranimines were also generated using PCl 5 and were used to polymerize Cl 3 P NSiMe 3, to give monotelechelic poly(dichlorophosphazenes). In addition, a mixed telechelic system was produced by the termination of an allylamino monotelechelic poly(dichlorophosphazene) chain with a bromoanilino phosphoranimine. In all cases, displacement of the chlorine atoms with sodium trifluoroethoxide yielded hydrolytically stable telechelic polymers with controlled molecular weights and low polydispersities.