Convenient Chemical Actinometer with 2-Hydroxy-4′-methoxychalcone

Abstract

Abstract The quantum yields for the photochemical conversion of 2-hydroxy-4′-methoxychalcone into the flavylium ion are in the range of 0.25—0.35 in acetic acid and 0.14—0.2 in aqueous ethanol at pH 2, depending on the wavelength of UV light. The quantum yields are essentially constant against any changes in the light intensity, temperature, or substrate concentration, which is a favorable feature regarding use as a convenient chemical actinometer. A one-photon mechanism involving excited-state proton-transferred tautomer is proposed.