Synthesis of fac‐Ir(ppy)3 end‐functionalized poly(1,3‐cyclohexadiene): single monomer addition of fac‐Ir(ppy)2(vppy) for well‐controlled polymer synthesis

Synthesis of the polymer whose end is functionalized by fac-Ir(ppy)3 (ppy = 2-phenylpyridyl) was achieved by using (living) anionic polymerization of 1,3-cyclohexadiene: the reaction of poly(1,3-cyclohexadienyl)lithium (PCHDLi) with fac-Ir(ppy)2(vppy) [vppy = 2-(4-vinylphenyl)pyridyl] resulted in nucleophilic attack of the carbanion in PCHDLi on the vinyl group of fac-Ir(ppy)2(vppy) selectively. Complexation of the pyridyl ring protected the α-carbons of fac-Ir(ppy)2(vppy) from the reaction of the anionic polymer. The homopolymerization of fac-Ir(ppy)2(vppy) did not occur, and only one molecule of fac-Ir(ppy)2(vppy) reacted with the carbanion of PCHDLi and was selectively incorporated into an end of poly(1,3-cyclohexadiene) (PCHD). Thus, the PCHD with fac-Ir(ppy)3 end-group was obtained with a well-controlled and defined polymer structure and molecular weight. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012