MANGANESE(III) PORPHYRIN SENSITIVE TO H2O2 DETECTION

The present study has been carried out to clarify the influence of H2O2 on photophysical behavior of a manganese porphyrin, namely: Mn(III)-5,10,15,20-tetra(4-methylphenyl) porphyrin chloride (MnTTPCl) and to reveal if this metalloporphyrin is suitable for usage as sensitive material in O-2 gas detection. Upon increasing the concentration of the H2O2 solution, the decrease of the absorption intensity of the Soret (V) band was noticed as a linear function with a good correlation coefficient. The capacity of the manganese porphyrin to generate aggregates was investigated by AFM in different solvents (THF and CHCl3) before and after H2O2 introduction. In THF the AFM images of bare Mn-porphyrin displayed small triangular particles and platelets that are characteristic of H aggregates. These aggregates became larger but of the same shape after H2O2 interference. On the other side, CHCl3 favored micro-structured ring shapes, obtained by the subsequent side by side J-process of H-types architectures, these circular geometries coexisting together with triangular or straw like structures.