Department of Physics, Henan Normal University , Xinxiang 453007, China.
J Phys Chem A. 2015 Dec 24;119(51):12686-92. doi: 10.1021/acs.jpca.5b09430. Epub 2015 Dec 7.
The 1,3-bis(2-pyridylimino)-4,7-dihydroxyisoindole (BPD) is chosen to investigate the excited-state double proton transfer process (ESDPT). The IR spectra, bond distance, and angle analyses show that the two intramolecular hydrogen bonds in the BPD molecule, formed between hydroxyl group and pyridine-type nitrogen atom, are significantly strengthened in the S1 state. The potential energy surfaces in both S0 and S1 states are scanned with varying O-H bond lengths to visually investigate the double proton transfer mechanism. Compared with previous investigations, the proton transfer process can be interpreted in more detail. The hydrogen bond strengthening promotes the proton transfer in the S1 state effectively. The large Stocks shift observed in the experiment can be explained more comprehensively according to the ESDPT mechanism.
1,3-双(2-吡啶亚氨基)-4,7-二羟基异吲哚（BPD）被选择来研究激发态双质子转移过程（ESDPT）。红外光谱、键长和键角分析表明，BPD 分子中两个羟基和吡啶型氮原子之间形成的两个分子内氢键在 S1 态显著增强。通过改变 O-H 键长扫描 S0 和 S1 态的势能面，直观地研究了双质子转移机制。与以前的研究相比，可以更详细地解释质子转移过程。氢键的增强有效地促进了 S1 态的质子转移。根据 ESDPT 机制，可以更全面地解释实验中观察到的大斯托克斯位移。
