Approaching 25 years since its invention, atom transfer radical polymerization (ATRP) is established as a powerful technique to prepare precisely defined polymeric materials. This perspective focuses on the relation between structure and activity of ATRP catalysts, and the consequent choice of the initiating system, which are paramount aspects to well‐controlled polymerizations. The ATRP mechanism is discussed, including the effect of kinetic and thermodynamic parameters and side reactions affecting the catalyst. The coordination chemistry and activity of copper complexes used in ATRP are reviewed in chronological order, while emphasizing the structure–activity correlation. ATRP‐initiating systems are described, from normal ATRP to low ppm Cu systems. Most recent advancements regarding dispersed media and oxygen‐tolerant techniques are presented, as well as future opportunities that arise from progressively more active catalysts and deeper mechanistic understanding.

中文翻译：

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原子转移自由基聚合：数十亿倍的活性催化剂和新的引发体系

原子转移自由基聚合（ATRP）自发明以来已接近25年，它是制备精确定义的聚合材料的有力技术。该观点侧重于ATRP催化剂的结构与活性之间的关系，以及引发剂系统的选择，这是控制聚合效果的最重要方面。讨论了ATRP机理，包括动力学和热力学参数的影响以及影响催化剂的副反应。按时间顺序回顾了ATRP中使用的铜配合物的配位化学和活性，同时强调了结构与活性之间的关系。描述了从常规ATRP到低ppm Cu系统的ATRP引发系统。提出了有关分散介质和耐氧技术的最新进展，