title: Visible-Light-Initiated Thiol-Michael Addition Polymerizations with Coumarin-Based Photobase Generators: Another Photoclick Reaction Strategy.
abstract: An efficient visible-light-sensitive photobase generator for thiol-Michael addition reactions was synthesized and evaluated. This highly reactive catalyst was designed by protecting a strong base (tetramethyl guanidine, TMG) with a visible-light-responsive group which was a coumarin derivative. The coumarin-coupled TMG was shown to exhibit extraordinary catalytic activity toward initiation of the thiol-Michael reaction, including thiol-Michael addition-based polymerization, upon visible-light irradiation, leading to a stoichiometric reaction of both thiol and vinyl functional groups. Owing to its features, this visible-light photobase generator enables homogeneous network formation in thiol-Michael polymerizations and also has the potential to be exploited in other visible-light-induced, base-catalyzed thiol-click processes such as thiol-isocynate and thiol-epoxy network-forming reactions.
authors.affiliation: Department of Chemical and Biological Engineering, University of Colorado, UCB 596, Boulder, Colorado 80309, United States.
authors.forename: Xinpeng
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Chemical and Biological Engineering, University of Colorado, UCB 596, Boulder, Colorado 80309, United States.
authors.forename: Weixian
authors.initials: W
authors.lastname: Xi
authors.affiliation: Department of Chemical and Biological Engineering, University of Colorado, UCB 596, Boulder, Colorado 80309, United States.
authors.forename: Chen
authors.initials: C
authors.lastname: Wang
authors.affiliation: Department of Chemical and Biological Engineering, University of Colorado, UCB 596, Boulder, Colorado 80309, United States; Faculty of Chemistry, Department of Polymer Chemistry, MCS University, pl. Marii Curie-Skłodowskiej 5, 20-031 Lublin, Poland.
authors.forename: Maciej
authors.initials: M
authors.lastname: Podgórski
authors.affiliation: Department of Chemical and Biological Engineering, University of Colorado, UCB 596, Boulder, Colorado 80309, United States.
authors.forename: Christopher N
authors.initials: CN
authors.lastname: Bowman