Zhang Jianyu, Hu Lianrui, Zhang Kaihua, Liu Junkai, Li Xingguang, Wang Haoran, Wang Zhaoyu, Sung Herman H Y, Williams Ian D, Zeng Zebing, Lam Jacky W Y, Zhang Haoke, Tang Ben Zhong
Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction and Institute for Advanced Study, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong 999077, China.
State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China.
J Am Chem Soc. 2021 Jun 30;143(25):9565-9574. doi: 10.1021/jacs.1c03882. Epub 2021 Jun 11.
Apart from the traditional through-bond conjugation (TBC), through-space conjugation (TSC) is gradually proved as another important interaction in photophysical processes, especially for the recent observation of clusteroluminescence from nonconjugated molecules. However, unlike TBC in conjugated chromophores, it is still challenging to manipulate TSC and clusteroluminescence. Herein, simple and nonconjugated triphenylmethane (TPM) and its derivatives with electron-donating and electron-withdrawing groups were synthesized, and their photophysical properties were systematically studied. TPM was characterized with visible clusteroluminescence due to the intramolecular TSC. Experimental and theoretical results showed that the introduction of electron-donating groups into TPM could red-shift the wavelength and increase the efficiency of clusteroluminescence simultaneously, due to the increased electronic density and stabilization of TSC. However, TPM derivatives with electron-withdrawing groups showed inefficient or even quenched clusteroluminescence caused by the vigorous excited-state intramolecular motion and intermolecular photoinduced electron transfer process. This work provides a reliable strategy to manipulate TSC and clusteroluminescence.
除了传统的通过化学键共轭（TBC）外，空间共轭（TSC）逐渐被证明是光物理过程中的另一种重要相互作用，特别是对于最近从非共轭分子中观察到的聚集发光。然而，与共轭发色团中的TBC不同，操纵TSC和聚集发光仍然具有挑战性。在此，合成了具有供电子和吸电子基团的简单非共轭三苯甲烷（TPM）及其衍生物，并系统地研究了它们的光物理性质。TPM由于分子内TSC而表现出可见的聚集发光。实验和理论结果表明，将供电子基团引入TPM可以同时使波长红移并提高聚集发光效率，这是由于电子密度增加和TSC的稳定性增强。然而，具有吸电子基团的TPM衍生物由于剧烈的激发态分子内运动和分子间光致电子转移过程而表现出低效甚至猝灭的聚集发光。这项工作为操纵TSC和聚集发光提供了一种可靠的策略。
