Synthesis, crystal structure and photoluminescent behaviors of 3-(1H-benzotriazol-1-yl)-4-methyl-benzo[7,8]coumarin

A novel coumarin derivative containing an electron-transporting moiety (benzotriazole), 3-(1H-benzotriazol-1-yl)-4-methyl-benzo[7,8]coumarin (BMBC), was synthesized and characterized by element analysis, 1H NMR, FT-IR and UV–vis absorption spectra, TG-DTA and single crystal X-ray crystallography. Crystallographic data reveal a dihedral angle of 60.4° between the benzocoumarin and benzotriazole rings, which is attributed to the spatial hindrance of a 4-positioned methyl group. The photoluminescent behaviors of BMBC doped in PMMA were discussed. The compound exhibits a strong blue emission under ultraviolet light excitation. The ground-state geometries, the lowest energy transition and the UV–vis spectrum of BMBC have been studied with density functional theory (DFT) and time-dependent density functional theory (TD-DFT) at B3LYP/6-31G(d) level, showing that the calculation outcomes are in good agreement with experimental data.