Synthesis,Crystal Structure and Photoluminescence of Ethyl Coumarin-3-carboxylate Derivatives

The ethyl coumarin-3-carboxylate(1) and its two derivatives,ethyl 7-methoxy-2-oxo-2H-chromene-3-carboxylate(2) and ethyl 7-(3-methylbut-2-enyloxy)-2-oxo-2H-chromene-3-carboxylate(3),were synthesized,characterized and their UV-vis spectra and photoluminescence were investigated.Compound 2 crystallizes in the monoclinic system with space group C2/c,a = 25.884(4),b = 6.8365(11),c = 13.816(2) ,β = 104.876(2)°,V = 2362.9(7) 3,Z = 8,Dc = 1.396 g/cm3,Mr = 248.23,F(000) = 1040 and μ = 0.108 mm–1.Compound 3 crystallizes in the monoclinic system with space group P21/c,a = 15.685(6),b = 8.373(3),c = 13.063(5) ,β = 111.862(6)°,V = 1592.2(10) 3,Z = 4,Dc = 1.261 g/cm3,Mr = 302.31,F(000) = 640 and μ = 0.093 mm–1.Both the absorption and emission of the two derivatives were stronger than that of ethyl coumarin-3-carboxylate due to the larger conjugation of their electron donor group moiety at the 7-position.Under ultraviolet light excitation,the two derivatives exhibit strong blue-violet emission.