Kinetics of Photoreactive 4,4′-Dimethylbenzophenone Nanocrystals: Relative Contributions to Triplet Decay from Intermolecular H-Atom Transfer and Reductive Charge Transfer Quenching
Kinetics of Photoreactive 4,4′-Dimethylbenzophenone Nanocrystals: Relative Contributions to Triplet Decay from Intermolecular H-Atom Transfer and Reductive Charge Transfer Quenching
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光反应性 4,4-二甲基二苯甲酮纳米晶体的动力学：分子间氢原子转移和还原电荷转移猝灭对三重态衰变的相对贡献
DOI：
10.1021/acs.jpca.3c03828
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发表时间：
2023
期刊：
影响因子：
--
通讯作者：
Garcia-Garibay, Miguel A.
中科院分区：
文献类型：
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作者：
King, Jared;Garcia-Garibay, Miguel A.
已知4，4 ′-二甲基二苯甲酮（DMBP）晶体通过分子间H原子转移反应，随后是自由基对复合。为了确定H原子转移反应对三重态酮失活的贡献，使用水性纳米晶悬浮液获得瞬态吸收光谱和动力学。ca的单指数寿命。1185 ns，没有氘同位素效应和无效的产物形成表明，该反应并没有显着贡献的三重态衰变的动力学。相比之下，所观察到的寿命与之前的观察结果一致，p，p′-二取代二苯甲酮通过还原电荷转移机制进行有效的自猝灭过程。
Crystals of 4,4′-dimethylbenzophenone (DMBP) are known to react by intermolecular H atom transfer, followed by radical pair recombination. To determine the contribution of the H atom transfer reaction to the deactivation of the triplet ketone, transient absorption spectra and kinetics were obtained using aqueous nanocrystalline suspensions. Single-exponential lifetimes of ca. 1185 ns with no deuterium isotope effect and inefficient product formation suggest that the reaction does not contribute significantly to the kinetics of triplet decay. By contrast, the observed lifetime is consistent with previous observations withp,p′-disubstituted benzophenones that undergo an efficient self-quenching process by a reductive charge transfer mechanism.