Ground and excited state proton transfer of 4-methyl- 2,6-diacetylphenol in some highly polar aprotic solvents: Interaction with base

Abstract

The proton transfer processes of the ground and excited states of 4-methyl-2, 6-diacetylphenol (MAOH) have been investigated by means of absorption, emission, nanosecond and picosecond transient emission spectroscopy at different temperatures. The fluorescence quantum yields are found to be dependent on temperature, excitation energy and added base. Unlike 4-methyl-2, 6-diformylphenol (MFOH), MAOH shows a single fluorescence band at room temperature in dimethyl sulphoxide and N,N-dimethylformamide and at 77K it does not exhibit any phosphorescence emission. The fluorescence lifetime and decay. rates of MAOH are temperature dependent and are relatively faster than those of MFOH. The solute-solvent interaction appears to play an important role in the proton transfer reaction of MAOH.