The organometallic-mediated radical polymerization (OMRP) of methyl methacrylate (MMA), styrene, and vinyl acetate, mediated by a novel tert-butyl-substituted amine–bis(phenolate) iron(II) complex in the absence of a halide source, accesses an organometallic-only route to controlled radical polymerization. Detailed kinetic and end-group studies were used to further understand the mechanism of control and the relative rates of propagation and termination reactions by using V-70, a low-temperature radical initiator. For the polymerization of MMA, propagation is favored at low conversions, with good control and reasonable dispersities achieved. Mechanistic studies suggest propagation proceeds through a RT-OMRP mechanism, while termination reactions become dominant at higher conversions. The polymerization temperature greatly affects the nature of termination, tuning whether bimolecular termination or catalytic chain transfer (CCT) dominates. With careful control of reaction conditions, the polymerization of styrene also shows good control, with dispersities as low as 1.27, and while not comparable to ATRP conditions, this research represents the most effective iron-mediated OMRP of styrene to date.

中文翻译：

---

了解有机金属介导的自由基与铁（II）胺-双（酚盐）的自由基聚合

在没有卤化物源的情况下，由新型的叔丁基取代的胺-双（酚盐）铁（II）络合物介导的甲基丙烯酸甲酯（MMA），苯乙烯和乙酸乙烯酯的有机金属介导的自由基聚合（OMRP），访问仅限于有机金属的途径以进行受控的自由基聚合。通过使用低温自由基引发剂V-70，进行了详细的动力学和端基研究，以进一步了解控制机理以及相对的繁殖和终止反应速率。对于MMA的聚合，在低转化率下有利于繁殖，并具有良好的控制和合理的分散性。机理研究表明，传播通过RT-OMRP机制进行，而终止反应在较高的转化率下占主导地位。聚合温度极大地影响了封端的性质，调整了双分子封端还是催化链转移（CCT）占主导地位。通过仔细控制反应条件，苯乙烯的聚合反应也显示出良好的控制效果，分散度低至1.27，虽然不能与ATRP条件相提并论，但这项研究代表了迄今为止最有效的铁介导的OMRP。