Theoretical studies on fluorescence of phenol and 1-naphthol in both acid and alkali solutions

Abstract

The molecular structures of the ground state and the first singlet excited state for C 6 H 5 OH 2 + , C 6H 5OH, C 6H 5O −, C 10 H 7 OH 2 + , C 10H 7OH and C 10H 7O −, the forms of phenol and 1-naphthol in acid and alkali solutions, were optimized by ab initio HF and configuration interaction with singlet excitations (CIS) method, respectively. Their fluorescent spectra were obtained by the time-dependent density functional theory (TD-DFT) using the B3LYP method with the 6-31+G (d) basis set. The frontier molecular orbital characteristics, fluorescent spectrum and proton affinities had been analyzed systematically in order to study different fluorescence of phenol and 1-naphthol in acid and alkali solutions. It was found that C 6H 5OH and C 6 H 5 OH 2 + are the main forms of phenol in acid solution, but C 6H 5O − in alkali solution; C 10H 7OH and C 10H 7O − are the main forms of 1-naphthol in alkali solution, but C 10 H 7 OH 2 + in acid solution. The calculated results are in good agreement with the experimental data.