Photochemistry and photophysics of a morpholino methylthio phenyl ketone: A steady-state, picosecond pump-probe laser spectroscopy and molecular modeling investigation

The photophysics of 2-methyl-1-4-(methylthio) phenyl]-2-(4-morpholinyl)-1-propanone TPMK, compared to that of two reference compounds (2-methyl-1-phenyl-2-(4-morpholinyl)-1-propanone and 1-4-(methylthio)phenyl]-ethanone), was studied by means of absorption spectroscopy, phosphorescence and time-resolved absorption spectroscopy. A four-level kinetic scheme has been proposed for TPMK as an explanation for the observed excited state processes. A strong solvent effect has been noticed upon the excited state lifetimes. Modeling calculations help to describe the excited state properties.