Synthesis,Structure and Fluorescence Study of 3-Bromo-7-methyloxy-4-methylcoumarin

Coumarin derivative 3-bromo-7-methyloxy-4-methylcoumarin(C11H9BrO3) was synthesized and characterized by FT-IR,1H NMR spectra,and thermal analysis.The crystal structure was determined by X-ray single-crystal diffraction.The title compound crystallizes in the mono-clinic system,space group P21/n,with a = 7.770(16),b = 12.501(3),c = 10.627(2),β = 98.46(3)°,Mr = 269.09,V = 1021.0(4) 3,Z = 4,Dc = 1.751 g/cm3,μ = 4.008 mm-1,F(000) = 536,R = 0.0650 and wR = 0.1463.The optimization of the title compound was obtained by quantum chemical method at the SVWN5/6-31G** level.In the structure,the measured angles of the crystal structure are similar to those calculated,while the measured bond lengths are shorter than the calculated values due to the crystal field which functions to the molecule.The title compound also shows good fluorescent behaviors and good linear relationship with the equal concentration gradient in methanol.