Tetradentate amine-bis(phenolate) iron(III) halide complexes containing chloro substituents on the aromatic ring are extremely efficient catalysts for controlled radical polymerization. Molecular weights are in good agreement with theoretical values and dispersities are as low as 1.07 for substituted styrenes and methyl methacrylate polymerizations. Kinetic data reveal activity for styrene polymerization among the fastest reported to date, with the excellent control shown to be electronic rather than steric in origin. Mechanistic studies implicate a multi-mechanism system with cooperation between atom transfer radical polymerization (ATRP) and organometallic mediated radical polymerization (OMRP). The in situ reduction of the Fe(III) complex with ascorbic acid or tin octanoate allows polymerizations to be initiated by both 1-phenylethyl chloride (1-PECl, ATRP regime) and azobisisobutyronitrile (AIBN, OMRP regime), to explore the mechanism of control and offer unique initiation pathways. Selected high pressure and computational studies will be presented to support mechanistic conclusions.

Single site iron complexes in controlled radical polymerizations: Exploring reaction scope and mechanism

248th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.