Highly Twisted <i>N</i>,<i>N</i>-Dialkylamines as a Design Strategy to Tune Simple Aromatic Hydrocarbons as Steric Environment-Sensitive Fluorophores
作者:Shunsuke Sasaki、Satoshi Suzuki、W. M. C. Sameera、Kazunobu Igawa、Keiji Morokuma、Gen-ichi Konishi
DOI:10.1021/jacs.6b03749
日期:2016.7.6
intersection (MECI) between S1 and S0 states was found to have a Dewar-benzene like structure. Although this can be reached efficiently in liquid phase for fast internal conversion, a large amplitude motion is required to reach this MECI, which is prohibited in the solid state and caused efficient AIE. This strategy is used to find experimentally that naphthalene analogues are also efficient AIE luminogens
从实验和理论上研究了 9,10-双 (N,N-二烷基氨基) 蒽 (BDAAs) 荧光的空间环境敏感性。提出了一种新的设计策略,可以将简单的芳烃调节为有效的聚集诱导发光 (AIE) 发光原和分子转子。对于各种 BDAA,观察到显着的斯托克斯位移和有效的固态荧光。BDAA-甲基的计算表明,在基态 (S0) 构象中,锥体胺基团高度扭曲,因此它们的孤对轨道不能与蒽 π 轨道共轭。荧光发生在 S1 最小值,其中一个或两个胺基被平面化。S1 激发态最小值的稳定性以及 S0 态的不稳定是大斯托克斯位移的起源。非绝热转变速率的实验测量表明,二烷基氨基(或强给电子)基团的对位双取代是快速内部转化的关键。发现 S1 和 S0 状态之间的最小能量圆锥交点 (MECI) 具有类似杜瓦苯的结构。虽然这可以在液相中有效地达到以实现快速内部转化,但需要大振幅运动才能达到此 MECI,这在固态中是被禁止的,并导致了高效的