Halogenation of a twisted non-polar π-system as a tool to modulate phosphorescence at room temperature |
| |
| Authors: | Giliandro Farias Cristian A M Salla Murat Aydemir Ludmilla Sturm Pierre Dechambenoit Fabien Durola Bernardo de Souza Harald Bock Andrew P Monkman Ivan H Bechtold |
| |
| Institution: | 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.; Department of Physics, Durham University, South Road, Durham DH1 3LE UK.; Erzurum Technical University, Department of Fundamental Sciences, Erzurum Turkey ; Centre de Recherche Paul Pascal, CNRS, Université de Bordeaux, 115, av. Schweitzer, 33600 Pessac France, |
| |
| Abstract: | 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.Twisted π-systems investigation showed a very unusual HAE, influencing independently the ISC and the dual phosphorescence emission, one being very persistent at room temperature and visible by eye in powder. |
| |
| Keywords: | |
|
|
