Fluorescence and pi-hydrogen bonding in naphthols

Dept. of Pure Chemistry, University College of Science, Calcutta-9, India.

Abstract

From the measurement of relative fluorescence intensity of α- and β-naphthol in n-heptane containing benzene, toluene and xylene, it has been concluded that there is pihydrogen bond formation between the hydroxyl group of naphthol and the π-electron system of benzenoid hydrocarbons. The equilibrium constants estimated from the fluorescence measurement have been found to be higher than those obtained from absorption data. This has been interpreted in terms of stronger proton donor character of naphthols in electronically excited state.