Seoul National University, Department of Chemistry, Seoul, 08826, Republic of Korea.
Seoul National University, Department of Biophysics and Chemical Biology, Seoul, 08826, Republic of Korea.
Sci Rep. 2017 Jun 20;7(1):3863. doi: 10.1038/s41598-017-04114-9.
Excited state dynamics of common yellow dye quinophthalone (QPH) was probed by femtosecond transient absorption spectroscopy. Multi-exponential decay of the excited state and significant change of rate constants upon deuterium substitution indicate that uncommon nitrogen-to-oxygen excited state intramolecular proton transfer (ESIPT) occurs. By performing density functional theory (DFT) and time-dependent density functional theory (TDDFT) calculations, we found that adiabatic surface crossing between the S and S states takes place in the photoreaction. Unlike most cases of ESIPT, QPH does not exhibit tautomer emission, possibly due to internal conversion or back-proton transfer. The ESIPT of QPH presents a highly interesting case also because the moieties participating in ESIPT, quinoline and aromatic carbonyl, are both traditionally considered as photobases.
采用飞秒瞬态吸收光谱技术研究了常见黄色染料醌式萘酞酮（QPH）的激发态动力学。激发态的多指数衰减和氘取代时速率常数的显著变化表明，发生了不常见的氮到氧的激发态分子内质子转移（ESIPT）。通过进行密度泛函理论（DFT）和含时密度泛函理论（TDDFT）计算，我们发现光反应中存在 S 和 S 态之间的绝热表面交叉。与大多数 ESIPT 情况不同，QPH 不显示互变异构体发射，这可能是由于内转换或反向质子转移。QPH 的 ESIPT 也是一个非常有趣的案例，因为参与 ESIPT 的部分，喹啉和芳香羰基，都被传统地认为是光碱基。
