Oxygen‐enhanced superoxido copper‐catalyzed ATRP accelerated by light

Abstract

AbstractOxygen‐enhanced atom transfer radical polymerization (ATRP) via the formation of a superoxido copper complex, has recently emerged as a powerful tool for the synthesis of well‐defined polymers. However, relatively long reaction times (>8 h) were required to reach high monomer conversions. Herein, we explore the influence of light in this new polymerization procedure. Under UV irradiation, a significant enhancement over the polymerization rate was observed resulting in near‐quantitative monomer consumption (>90%) within 2 h and narrow molar mass distributions (Đ = 1.07). The rate acceleration was attributed to the fast reduction of the superoxido copper complex to Cu(I)Br under UV irradiation, as confirmed via detailed UV–Vis kinetic experiments. In addition, the induction period was completely eliminated, which is in stark contrast to conventional photo‐ATRP (utilizing Cu(II)Br), thus further highlighting the superiority of the presented system. The synergy of the superoxido complex and UV irradiation enabled the synthesis of low‐dispersity homopolymers with molecular weights ranging from 6000 to 300,000. The high end‐group fidelity of the system was further demonstrated via successful in‐situ chain‐extensions.