AbstractThe design and synthesis of four twisted donor‐acceptor (D‐A) thermally activated delayed fluorescence (TADF) molecules CBZ‐IQ, CBZ‐2FIQ, DI‐IQ and DI‐2FIQ is reported in this work based on diindolocarbazole (DI) and phenyl carbazole as donor and indoloquinoxalines as acceptor. These compounds serve as photocatalysts for organic transformations. Theoretical calculations and experimental data showed reasonable singlet and triplet energy gaps of 0.17‐0.26 eV for all compounds. All molecules showed increase in fluorescence quantum yields after degassing the solution and the transient photoluminescence decay showed two components: shorter prompt components (11.4 ns to 31 ns) and longer delayed components (36.4 ns to 1.5 μs) which further indicate the occurrence of TADF process. Cyclic voltammetry studies indicated well‐suited excited state redox potentials of all compounds to catalyze organic transformations such as heteroarene arylation. Accordingly, photocatalytic C−H arylation of heteroarenes were performed using these compounds with excellent isolated yields of upto 80 %. Due to their suitable efficient triplet energy levels, all the emitters were also employed as energy transfer photocatalysts in E to Z isomerization of stilbene with the excellent conversion of ~90 %.
摘要 本研究以二吲哚咔唑(DI)和苯基咔唑为供体,以吲哚喹喔啉为受体,设计并合成了四种扭曲的供体-受体(D-A)热激活延迟荧光(TADF)分子 CBZ-IQ、CBZ-2FIQ、DI-IQ 和 DI-2FIQ。这些化合物可用作有机转化的光催化剂。理论计算和实验数据显示,所有化合物的单线能隙和三线能隙均在 0.17-0.26 eV 之间。溶液脱气后,所有分子的荧光量子产率都有所提高,瞬态光致发光衰减显示出两种成分:较短的迅速成分(11.4 ns 至 31 ns)和较长的延迟成分(36.4 ns 至 1.5 μs),这进一步表明发生了 TADF 过程。循环伏安研究表明,所有化合物的激发态氧化还原电位都非常适合催化杂芳烃芳基化等有机转化。因此,利用这些化合物对杂芳基进行了光催化 C-H 芳基化反应,分离产率高达 80%。由于所有发射体都具有合适的高效三重能级,因此在苯乙烯的 E 到 Z 异构化过程中,它们也被用作能量转移光催化剂,转化率高达约 90%。