3-Ethyl-3,4,4a, 10a-tetrahydro-2H- 1,5-dioxa-3-aza-phenanthren-6-one （C13H13NO3, Mr = 231.24） was synthesized and characterized by FT-IR, H NMR spectra, and thermal analysis. The crystal structure was determined by X-ray single-crystal diffraction. It crystallizes in methanol. The crystal is of orthorhombic system, space group Pbca with a = 8.9250（18）, b = 12.605（3）, c = 20.552（4） A, Z = 8, V = 2312.1（8） A3, Dc = 1.329 mg/m3, p = 0.095 mm-, F（000） = 976, R = 0.0583 and wR = 0.1340. Thermal analysis reveals that it is stable below 100 C. Fluorescence spectra analysis shows that its fluorescence intensity is twice as that of 7-hydroxylcoumarin in methanol solution with the same concentration.
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.
