Center for Photochemical Sciences at Bowling Green State University, Bowling Green, Ohio 43403, United States.
J Phys Chem A. 2011 Jun 23;115(24):6366-75. doi: 10.1021/jp200507j. Epub 2011 May 18.
The nonradiative decay of four dipolar fluorenone derivatives (FODs) was systematically investigated using steady state and time-resolved UV-vis absorption and fluorescence measurements combined with cyclic voltammetry. Analysis of the frontier orbital localization of the global minimum geometry and the vertical transitions was carried out from DFT calculations. The first singlet excited state was found to be π-π* in all derivatives regardless of the polarity of the solvent. Charge separation/recombination dominates the singlet excited state deactivation for carbazole-containing FODs. Intersystem crossing (ISC) operates exclusively in the 3,6-disubstituted variants as evidenced by phosphorescence experiments. In the case of CPAFO36, ISC competes disadvantageously with CT deactivation.
采用稳态和时间分辨紫外-可见吸收和荧光测量以及循环伏安法，系统研究了四种偶极型芴酮衍生物（FODs）的非辐射衰减。通过 DFT 计算，对全局最小几何形状和垂直跃迁的前线轨道定位进行了分析。无论溶剂的极性如何，所有衍生物的第一单重激发态均被发现为π-π*。对于含咔唑的 FODs，电荷分离/重组主导单重激发态失活。磷光实验证明，系间窜越（ISC）仅在 3,6-取代变体中起作用。对于 CPAFO36，ISC 与 CT 失活竞争不利。
