Telitel Sofia, Vallet Anne-Laure, Flanigan Darrin M, Graff Bernadette, Morlet-Savary Fabrice, Rovis Tomislav, Lalevée Jacques, Lacôte Emmanuel
Institut de Science des Matériaux de Mulhouse IS2M - UMR CNRS 7361, Université de Haute-Alsace, 15 rue Jean Starcky, 68057 Mulhouse Cedex (France), Fax: (+33) 3-89-33-60-69.
ICSN CNRS, Avenue de la Terrasse, 91198 Gif-sur-Yvette Cedex (France).
Chemistry. 2015 Sep 21;21(39):13772-7. doi: 10.1002/chem.201500499. Epub 2015 Aug 3.
A small library of triazolylidene-boranes that differ only in the nature of the aryl group on the external nitrogen atom was prepared. Their reactivity as hydrogen-atom donors, as well as that of the corresponding N-heterocyclic carbene (NHC)-boryl radicals toward methyl acrylate and oxygen, was investigated by laser flash photolysis, molecular orbital calculations, and ESR spin-trapping experiments, and benchmarked relative to the already known dimethyltriazolylidene-borane. The new NHC-boranes were also used as co-initiators for the Type I photopolymerization of acrylates. This allowed a structure-reactivity relationship with regard to the substitution pattern of the NHC to be established and the role of electronic effects in the reactivity of NHC-boryl radicals to be probed. Although their rate of addition to methyl acrylate depends on their electronegativity, the radicals are all nucleophilic and good initiators for photopolymerization reactions.
制备了一个小型的三唑亚基硼烷库，这些硼烷仅在外围氮原子上的芳基性质上有所不同。通过激光闪光光解、分子轨道计算和电子自旋共振自旋捕获实验，研究了它们作为氢原子供体的反应活性，以及相应的氮杂环卡宾（NHC）硼基自由基对丙烯酸甲酯和氧气的反应活性，并相对于已知的二甲基三唑亚基硼烷进行了基准测试。这些新型NHC硼烷还被用作丙烯酸酯I型光聚合的共引发剂。这使得能够建立关于NHC取代模式的结构-反应活性关系，并探究电子效应在NHC硼基自由基反应活性中的作用。尽管它们对丙烯酸甲酯的加成速率取决于其电负性，但这些自由基都是亲核的，并且是光聚合反应的良好引发剂。
