Synthesis, crystal structure and photoluminescence of 3-(1-benzotriazole)-4-methyl-coumarin

A novel coumarin derivative containing an electron-transporting moiety (benzotriazole), 3-(1-benzotriazole)-4-methyl-coumarin (BMC), was synthesized from starting substances, i.e. benzotriazole and 2-hydroxyacetophenone. The compound structure was verified by FT-IR, H-1 NMR, element analysis and single crystal X-ray crystallography. Crystallographic data reveal a dihedral angle of 108 degrees between the coumarin and benzotriazole rings, which is attributed to the spatial hindrance of a 4-positioned methyl group. The fluorescence and UV-vis absorption of BMC were discussed. The compound exhibits a strong UV emission peak at 385 nm under 360 ran excitation. The molecular structure of BMC was optimized using density functional theory (DFT) at B3LYP/6-31G(d) level, showing that the optimized geometric parameters are in good agreement with experimental data. In addition, the HOMO and LUMO levels of BMC were deduced. (c) 2006 Elsevier B.V. All rights reserved.