Deep insight into the charge-transfer cocrystals: Decreasing structural overlap induced bathochromically shift emission

Solid-State Assembly and Photoluminescent Behavior of 5-(9H-Carbazol-9-yl)isophthalic Acid–Based Molecular Crystals Influenced by Solvents and Organic Counterparts

“…Notably, the two π-stacked carbazole planes are perfectly overlapped with the same centroid-to-centroid and interplanar separations of 3.697(2) Å (Figure a inset and Table S4). Due to the dense distribution of electron cloud on the carbazole plane, the π–π stackings in the CzIp lattice increase the electrostatic attractive forces through dipole–dipole interactions, , favorable for the intermolecular electron communications. Based on the above structural analyses, it can be concluded that each CzIp chromophore in the CzIp lattice is confined by one attractive π–π and four strong O COOH –H···O COOH interactions, resulting in a decrease in both the molecular vibrational degrees of freedom and nonradiative transition.…”

“…29,32−40 modifications of the constitute part by introducing multiple interacting sites or skillful selection of the compatible D−A pairs to obtain high-emissive and high-stable molecular crystals. 41 Possessing strong electron-donor ability and abundant synthetic accessibility, diverse carbazole derivatives, such as 9-(3-(pyren-1-yl)phenyl)-9H-carbazole, 42 halogenated phenyl, or alkyl tethered bi-and tricarbazoles, 43 have been used as donors to incorporate with electron-deficient coformers for triggering highly emissive molecule crystals. Herein, to obtain the luminescent crystalline materials stabilized by additional hydrogen-bonding interactions, 5-(9H-carbazol-9-yl)isophthalic acid (CzIp) with isophthalic acid attached to the carbazole parent is ingeniously designed as a fluorescent model substance (Scheme 1).…”