H-Bonding and C-H π assisted mechanofluorochromism of triphenylamine-containing vinylheterocycles bearing cyano and methyl groups

• Published in: New journal of chemistry 2018-11, Vol.42 (22), p.18269-18277
• Main Authors: Peng, Jiang, Zhao, Jinyu, Zheng, Longde, Ye, Kaiqi, Sun, Jingbo, Lu, Ran
• Format: Article
• Language: English
• Subjects: Absorption spectra; Crystal structure; Crystallinity; Crystallography; Crystals; Cyano groups; Emission spectra; Fluorescence; NMR; Nuclear magnetic resonance; Single crystals; Solid state; Synthesis; X ray spectra; X-ray diffraction
• ISSN: 1144-0546; 1369-9261
• DOI: 10.1039/c8nj03510e

New D-π-A-type triphenylamine-containing benzimidazoles, benzoxazoles and benzothiazoles have been synthesized. It was found that the introduction of a cyano group in vinyl and methyl in triphenylamine was favorable for producing mechanofluorochromism of the fused heterocyclic derivatives. The single crystal X-ray diffraction data revealed that the intermolecular interactions of the H-bonding formed from the cyano group and the C-H π interaction formed from the methyl group would rigidify the molecular conformations, leading to strong solid-state emission. Interestingly, the solid-state emission of the synthesized triphenylamine-containing fused heterocycles bearing cyano and/or methyl groups could be tuned by external mechanical forces on account of the transition between crystalline and amorphous states or between a highly ordered crystalline state and a less ordered state. The intermolecular interactions have affected the mechanofluorochromic performance of heterocycles.