Chen Meiling, Chen Yuzhuo, Zhang Ting, Zhang Hua, Xiao Zhiwen, Su Zhongzhen, Wu Yunan
State Key Laboratory of Oncology in South China, Guangdong Provincial Clinical Research Center for Cancer, Sun Yat-sen University Cancer Center Guangzhou 510060 China.
Department of Nuclear Medicine, Sun Yat-sen University Cancer Center Guangzhou 510060 China.
RSC Adv. 2024 Oct 11;14(44):32221-32228. doi: 10.1039/d4ra05807k. eCollection 2024 Oct 9.
This study reports the synthesis and photophysical analysis of three isomeric compounds, namely 3Fmo, 3Fmm, and 3Fmp, which were engineered using carbazole as the electron donor, phthalimide as the electron acceptor, and a benzene ring as the bridging moiety. Among these, 3Fmm was distinguished by its ability to exhibit immediate room-temperature white phosphorescence following the cessation of UV illumination, whereas 3Fmo and 3Fmp demonstrated TADF properties. Crystallographic analysis revealed unique intermolecular π-π stacking interactions within 3Fmm, absent in the other two isomers. Advanced TD-DFT computations indicated that such π-π stacking in 3Fmm not only facilitates intersystem crossing but also effectively reduces the free volume within the crystal, leading to a decrease in non-radiative transitions. These molecular interactions promote the manifestation of room-temperature phosphorescence. Furthermore, leveraging the superior luminescent properties of 3Fmo, the compound was successfully utilized in cellular imaging, where it achieved excellent imaging results, showcasing its potential for biomedical applications.
本研究报告了三种同分异构体化合物3Fmo、3Fmm和3Fmp的合成及光物理分析，这些化合物以咔唑作为电子供体、邻苯二甲酰亚胺作为电子受体，并以苯环作为桥连部分构建而成。其中，3Fmm的独特之处在于，在紫外光照射停止后，它能立即呈现室温白色磷光，而3Fmo和3Fmp则表现出热激活延迟荧光（TADF）特性。晶体学分析表明，3Fmm内存在独特的分子间π-π堆积相互作用，而其他两种异构体中不存在这种相互作用。先进的含时密度泛函理论（TD-DFT）计算表明，3Fmm中的这种π-π堆积不仅促进了系间窜越，还有效地减小了晶体内的自由体积，从而导致非辐射跃迁减少。这些分子间相互作用促进了室温磷光的显现。此外，利用3Fmo优异的发光特性，该化合物成功应用于细胞成像，取得了出色的成像结果，展示了其在生物医学应用中的潜力。
