Controlled Radical Polymerization Mediated by Amine-Bis(phenolate) Iron(III) Complexes

• Published in: Macromolecular rapid communications. Vol. 33; no. 5; pp. 414 - 418
• Main Authors: Allan, Laura E. N., MacDonald, Jarret P., Reckling, Amy M., Kozak, Christopher M., Shaver, Michael P.
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 16-03-2012; WILEY‐VCH Verlag; Wiley
• Subjects: Amines - chemistry; Applied sciences; atom transfer radical polymerization; controlled radical polymerization; Exact sciences and technology; Free Radicals - chemistry; iron; Iron - chemistry; Kinetics; Organic polymers; Phenols - chemistry; Physicochemistry of polymers; Polymerization; Polymers - chemical synthesis; Polymers - chemistry; polymethylmethacrylate; polystyrene; Preparation, kinetics, thermodynamics, mechanism and catalysts; Substituent effect; Bulk polymerization; polystyrene; Living polymer; Methyl methacrylate polymer; Aryloxy complex; polymethylmethacrylate; controlled radical polymerization; Complex catalyst; Experimental study; Free radical polymerization; atom transfer radical polymerization; Iron III Complexes; Styrene polymer; iron; Catalyst activity; Halo complex
• ISSN: 1022-1336; 1521-3927
• DOI: 10.1002/marc.201100872

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 polydispersity indexes (PDIs) are as low as 1.11 for styrene and methyl methacrylate polymerizations. Complexes containing alkyl substituents on the aromatic ring are less efficient. Kinetic data reveal activity for styrene polymerization among the fastest reported to date and initial studies implicate a multimechanism system. Despite the highly colored polymerization media, simple work‐up procedures yield pure white polymers.
Facile recovery of white polymers is essential for the commercialization of controlled radical polymerization. A new family of highly active, benign iron catalysts, believed to operate through a unique dual‐control mechanism, is reported. Despite the deep purple color of the complexes and polymerization media, simple precipitation yields pure white polymers with polydispersities as low as 1.1.