Twisted Donor−π–Acceptor Carbazole Luminophores with Substituent-Dependent Properties of Aggregated Behavior (Aggregation-Caused Quenching to Aggregation-Enhanced Emission) and Mechanoresponsive Luminescence Huichao Zhu Pengfei Chen Lin Kong Yupeng Tian Jiaxiang Yang 10.1021/acs.jpcc.8b05638.s005 https://acs.figshare.com/articles/dataset/Twisted_Donor_Acceptor_Carbazole_Luminophores_with_Substituent-Dependent_Properties_of_Aggregated_Behavior_Aggregation-Caused_Quenching_to_Aggregation-Enhanced_Emission_and_Mechanoresponsive_Luminescence/6989588 To get insight on how the donor (D)/acceptor (A) substitutions and their substitution pattern affect optical properties in solution and in the solid state, four novel carbazole derivatives <b>C1</b>–<b>C4</b> with different terminal groups (N­(CH<sub>3</sub>)<sub>2</sub>, H, Br, and CN) have been employed. Their single-crystal X-ray structures confirm that the twisted structures, intermolecular interactions, and loose molecular packing are functions of the terminal groups. Interestingly, they displayed substituent-dependent aggregation-induced behaviors and mechanochromic (MC) properties. <b>C1</b> showed aggregation-caused quenching because of the strong intermolecular π–π interaction, whereas <b>C2</b>, <b>C3,</b> and <b>C4</b> exhibit strong aggregation-enhanced emission characteristics, which contributed to the formation of J-aggregates. Different twisted conformations and molecular arrangements induce different mechanostimuli response behaviors for <b>C1</b>–<b>C4</b> between green-yellow to red color along with large red-shifts of 63, 30, 56, and 49 nm, respectively. <b>C1</b>, <b>C3</b>, and <b>C4</b> displayed obvious MC characteristics, but <b>C2</b> displayed irreversible mechanostimulus behavior. Powder X-ray diffraction and single-crystal X-ray analysis revealed that planarization of the twisted structure extended the π-conjugation and the destruction of the crystalline structure accounted for the tuned solid-state fluorescence. 2018-08-09 00:00:00 powder X-ray diffraction aggregation-enhanced emission characteristics mechanostimuli response behaviors single-crystal X-ray analysis C 4 exhibit single-crystal X-ray structures substitution MC C 1 CN interaction C 2 substituent-dependent aggregation-induced behaviors terminal groups