Synthesis, photoluminescent behaviors, and theoretical studies of two novel ketocoumarin derivatives.

Two new coumarin derivatives, 3-[3-(4-formylphenyl)prop-2-enoyl]-coumarin (FEC) and 4-hydroxy-3-[3-(4-formylphenyl)prop-2-enoyl]-coumarin (HFEC), were synthesized and characterized by MS, (1)H NMR, FT-IR, and TG. The UV-vis absorption and photoluminescence (PL) of FEC and HFEC were also studied. Results show that the two compounds exhibit high fluorescence quantum yields, large Stokes shifts, and strong blue emissions. The molecular structures, the lowest energy transitions, the resonance frequencies, and the UV-vis spectra of FEC and HFEC were calculated using the density functional theory (DFT) and time-dependent density functional theory (TD-DFT) at the B3LYP/6-31G(d) level.