[Theoretical study on fluorescence spectra of four kinds of p-substituted curcumin analogues].

Four kinds of p-substituted curcumin analogues were optimized at B3LYP/6-31G (d, p) level. On this basis, the excited states geometry structure was optimized by the CIS method, and finally the fluorescence emission spectra were calculated through the TD-DFT method. The results showed that: the four compounds, a large conjugated system, is preferably coplanar structure. Because of introducing hydroxyl and halogen atom on the benzene ring, the molecular pi-electron conjugation is relatively larger, emission wavelength is relatively longer, and fluorescence spectra show different degrees of red shift. As the electron donating group is hydroxy, the fluorescence phenomenon is more obviously red shifted.