Zhang Xinpeng, Wang Xiance, Chatani Shunsuke, Bowman Christopher N
Department of Chemical and Biological Engineering, University of Colorado Boulder, UCB 596, Boulder, Colorado 80309, United States.
ACS Macro Lett. 2021 Jan 19;10(1):84-89. doi: 10.1021/acsmacrolett.0c00809. Epub 2020 Dec 18.
A photoinitiation system that utilizes phosphonium tetraphenylborate as the key component was developed for the visible light-triggered nucleophile-catalyzed thiol-Michael addition reaction. This highly reactive catalyst was composed of a photocaged phosphine (methyldiphenylphosphonium tetraphenylborate, MDPP·HBPh), a photosensitizer (isopropylthioxanthone, ITX), and a radical scavenger (TEMPO). Unlike the prevailing photobase catalysts, this photoactivatable phosphine system triggers the thiol-Michael addition polymerization by a nucleophile-catalyzed mechanism and provides a controlled stoichiometric reaction between the thiol and the vinyl precursors. This approach enables the formation of homogeneous polymer networks upon low-energy visible light exposure and, thus, broadens its potential applications in bulk polymer materials synthesis and UV-sensitive bioscaffold formation.
开发了一种以四苯基硼酸鏻为关键成分的光引发体系，用于可见光引发的亲核催化剂催化的硫醇-迈克尔加成反应。这种高活性催化剂由光笼蔽膦（甲基二苯基鏻四苯基硼酸盐，MDPP·HBPh）、光敏剂（异丙基硫杂蒽酮，ITX）和自由基清除剂（TEMPO）组成。与普遍使用的光碱催化剂不同，这种可光活化的膦体系通过亲核催化剂催化的机制引发硫醇-迈克尔加成聚合反应，并在硫醇和乙烯基前体之间提供可控的化学计量反应。这种方法能够在低能量可见光照射下形成均匀的聚合物网络，从而拓宽了其在本体聚合物材料合成和对紫外线敏感的生物支架形成方面的潜在应用。
