College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, China.
School of Polymer Science and Engineering, University of Southern Mississippi, Hattiesburg, MS, 39406, USA.
Macromol Rapid Commun. 2020 Jan;41(1):e1900478. doi: 10.1002/marc.201900478. Epub 2019 Nov 10.
The photocatalyst Zn(II) meso-tetra(4-sulfonatophenyl)porphyrin (ZnTPPS) is found to substantially accelerate visible-light-initiated (red, yellow, green light) single unit monomer insertion (SUMI) of N,N-dimethylacrylamide into the reversible addition-fragmentation chain transfer (RAFT) agent, 4-((((2-carboxyethyl)thio)carbonothioyl)thio)-4-cyanopentanoic acid (RAFT ), in aqueous solution. Thus, under irradiation with red (633 nm) or yellow (593 nm) light with 50 mpm (moles per million mole of monomer) ZnTPPS at 30 °C, the rate enhancement provided by photoinduced energy or electron transfer (PET) is ≈sevenfold over the rate of direct photoRAFT-SUMI (without catalyst), which corresponds to achieving full and selective reaction in hours versus days. Importantly, the selectivity, as judged by the absence of oligomers, is retained. Under green light at similar power, higher rates of SUMI are also observed. However, the degree of enhancement provided by PET-RAFT-SUMI over direct photoRAFT-SUMI as a function of catalyst concentration is less and some oligomers are formed.
光催化剂 Zn(II) 中四(4-磺酸钠基苯基)卟啉(ZnTPPS) 被发现可显著加速可见光引发的(红光、黄光、绿光)N,N-二甲基丙烯酰胺单体对可逆加成-断裂链转移(RAFT)试剂 4-(((2-羧乙基)硫代)羰基硫代) 4-氰基戊酸(RAFT)的单单元插入(SUMI)。因此，在 30°C 下，用 50 mpm(每百万摩尔单体的摩尔数)的 ZnTPPS 在红光(633nm)或黄光(593nm)照射下，光诱导能量或电子转移(PET)提供的速率增强≈七倍于直接光 RAFT-SUMI(无催化剂)的速率，这相当于在几小时内实现完全和选择性反应，而不是几天。重要的是，根据没有低聚物的存在，保留了选择性。在类似功率的绿光下，也观察到 SUMI 更快的速率。然而，作为催化剂浓度函数的 PET-RAFT-SUMI 相对于直接光 RAFT-SUMI 提供的增强程度较小，并且形成了一些低聚物。
