Design of Rigid Cyclic Tripyrrins: The Importance of Intermolecular Interactions on Aggregation and Luminescence

Jun-Fei Wang, Yuhang Yao, Yingying Ning, Yin-Shan Meng, Chun-Liang Hou, Jing Zhang, Jun-Long Zhang

Index: 10.1039/C8QO00313K

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Abstract

We designed a cyclic tripyrrin “locked” by a bridging benzene-1,4-diol moiety which is perpendicular to tripyrrin plane. The cyclic structures promote the scaffold rigidity and enhances the fluorescence. While the halogen-substitution of bridging moiety was found to slightly affect the fluorescence of 1-3 in solution, such substitution significantly affects the aggregation behaviours and solid emission. 1 and 2 exhibit typical J-aggregate emission but 3 does not. Analysis of crystal packing combining with reduce density gradient (RDG) analysis suggest that the bridging moieties of 1-3 play an important role to induce the different crystal packing by tuning intermolecular interaction in solid state. Energy decomposition analysis using symmetry adapted perturbation theory (SAPT) revealed that such weak intermolecular interactions are mainly consist of halogen bond and π-π interactions.