Theoretical insights into the aggregation-induced emission by hydrogen bonding: a QM/MM study.
Theoretical insights into the aggregation-induced emission by hydrogen bonding: a QM/MM study.
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DOI：
10.1021/jp3002367
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发表时间：
2012-04
期刊：
影响因子：
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通讯作者：
Qunyan Wu;Qian Peng;Y. Niu;Xing Gao;Z. Shuai
中科院分区：
文献类型：
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作者：
Qunyan Wu;Qian Peng;Y. Niu;Xing Gao;Z. Shuai
采用量子力学和分子力学相结合的方法（QM/MM）和振动关联方法，结合含时密度泛函理论（TDDFT），研究了3-（2-氰基-2-苯乙烯基-Z）-NH-吲哚（CPEI）在固相中的激发态衰减过程.通过比较孤立的CPEI分子和分子簇，我们表明，通过分子间氢键相互作用的分子包装可以阻碍激发态的非辐射衰减，从而提高在固相中的荧光效率。聚集效应是通过阻碍低频振动来阻止非辐射衰变过程的。由于氢键的作用，孤立分子和聚集体的荧光量子产率对温度不敏感，其室温值与实验值一致.
We investigate the excited-state decay processes for the 3-(2-cyano-2- phenylethenyl-Z)-NH-indole (CPEI) in the solid phase through combined quantum mechanics and molecular mechanics (QM/MM) and vibration correlation formalisms for radiative and nonradiative decay rates, coupled with time-dependent density functional theory (TDDFT). By comparing the isolated CPEI molecule and the molecule-in-cluster, we show that the molecular packing through intermolecular hydrogen-bonding interactions can hinder the excited-state nonradiative decay and thus enhance the fluorescence efficiency in the solid phase. Aggregation effect is shown to block the nonradiative decay process through hindering the low-frequency vibration motions. The fluorescence quantum yields for both isolated molecule and aggregation are predicted to be insensitive to temperature due to the hydrogen-bonding nature, and their values at room temperature are consistent with the experiment.