Macromolecules 2015 "A Synthetic and Multispectroscopic Speciation Analysis of Controlled Radical Polymerization Mediated by Amine–Bis(phenolate)iron Complexes" - EPSRC EPSRC EP/M000842/1

The mechanism of reversible-deactivation radical polymerization (RDRP) mediated by chloro-substituted amine–bis(phenolate)iron complexes was studied via a combination of Mössbauer, EPR, NMR, and online Vis/NIR spectroscopy. It was found that styrene polymerization operates via an atom-transfer radical polymerization (ATRP) mechanism when alkyl halide is present, whereas an interplay between ATRP and organometallic-mediated radical polymerization (OMRP) equilibria occurs during MMA polymerization. The preparation of the amine–bis(phenolate)iron(II) complex, [O2NN′]FeII, allowed polymerizations to be performed under an OMRP-only regime free of alkyl halide that yields dispersities as low as 1.29 for MMA polymerization.

本研究结合穆斯堡尔（Mössbauer）谱、电子顺磁共振（EPR）谱、核磁共振（NMR）谱以及在线可见/近红外（Vis/NIR）光谱，对氯取代胺双酚铁配合物介导的可逆失活自由基聚合（reversible-deactivation radical polymerization, RDRP）机制展开了探究。研究发现，当体系中存在烷基卤化物时，苯乙烯聚合遵循原子转移自由基聚合（atom-transfer radical polymerization, ATRP）机制；而在甲基丙烯酸甲酯（MMA）聚合过程中，则存在原子转移自由基聚合与有机金属介导自由基聚合（organometallic-mediated radical polymerization, OMRP）两种平衡机制的相互作用。通过制备胺双酚铁(II)配合物[O2NN′]Fe(II)，可实现无烷基卤化物的纯OMRP聚合体系，该条件下甲基丙烯酸甲酯聚合的分子量分散度可低至1.29。