Effects of environment on the photophysical characteristics of mesotetrakis methylpyridiniumyl porphyrin (TMPyP)

Abstract

Porphyrins are an important class of organic molecules, with interesting linear and nonlinear optical properties given mainly by their extended π-conjugation structure. Their photophysical properties can be greatly affected by the surrounding environment, which can be used to tune its final properties. Here we report on an experimental study of the photophysical properties of meso-tetrakis (methylpyridiniumyl) porphyrin (TMPyP) in aqueous and in several organic solvents and its interaction with micelles formed from negatively charged sodium dodecylsulphate (SDS), positively charged cetyl trimethyl ammonium bromide (CTAB) and neutral TRITON X-100. By using the Z-scan technique, flash-photolysis and time-resolved fluorescence techniques, we were able to evaluate the excited state dynamics of the TMPyP, and observed that the tetrapyrrole ring plays important role due to hydrogen bonds formation between nitrogen atom and water, while the side groups determine the porphyrin localization in non-aqueous micelle part.