Farias Giliandro, Salla Cristian A M, Aydemir Murat, Sturm Ludmilla, Dechambenoit Pierre, Durola Fabien, de Souza Bernardo, Bock Harald, Monkman Andrew P, Bechtold Ivan H
Department of Chemistry, Universidade Federal de Santa Catarina 88040-900 Florianópolis SC Brazil
Department of Physics, Universidade Federal de Santa Catarina 88040-900 Florianópolis SC Brazil
Chem Sci. 2021 Nov 1;12(45):15116-15127. doi: 10.1039/d1sc04936d. eCollection 2021 Nov 24.
Halogenation of a twisted three-fold symmetric hydrocarbon with F, Cl or Br leads to strong modulation of triplet-triplet annihilation and dual phosphorescence, one thermally activated and the other very persistent and visible by eye, with different relative contributions depending on the halide. The room temperature phosphorescence is highly unusual given the absence of lone-pair-contributing heteroatoms. The interplay between the spin-orbit coupling matrix elements and the spatial configuration of the triplet state induces efficient intersystem crossing and thus room temperature phosphorescence even without relying on heteroatomic electron lone pairs. A ninefold increase of the ISC rate after introduction of three bromine atoms is accompanied by a much higher 34-fold increase of phosphorescence rate.
用氟、氯或溴对一种扭曲的三重对称烃进行卤化，会导致三重态-三重态湮灭和双重磷光的强烈调制，一种是热激活的，另一种非常持久且肉眼可见，其相对贡献因卤化物而异。鉴于不存在贡献孤对电子的杂原子，室温磷光非常罕见。自旋-轨道耦合矩阵元与三重态的空间构型之间的相互作用会引发有效的系间窜越，因此即使不依赖杂原子的孤对电子也能实现室温磷光。引入三个溴原子后，系间窜越速率提高了九倍，同时磷光速率大幅提高了34倍。
