The influence of solvent polarity on spectroscopic properties of 5-[4-(5-carboxy-1-butoxy)-phenyl]-10,15,20-tris(4-N-methylpyridiniumyl)porphyrin and its complexes with Fe(III) and Mn(III) ions

The spectral properties of water-soluble cationic 5-[4-(5-carboxy-1-butoxy)-phenyl]-10,15,20-tris(4-N-methylpyridiniumyl)porphyrin and its complexes with Fe(III) and Mn(III) were studied in water and organic solvents (MeOH, EtOH, DMSO and DMF). The influence of solvent polarity on wavelengths of the absorbance and fluorescence band maxima is described, in connection with the large Stokes shifts of approximately 200 nm observed for all the porphyrin compounds. The Soret band λmax shift is correlated with Reichardt’s polarity parameter. The ability to fluorescence of manganese (III) and iron (III) complexes of 5-[4-(5-carboxy-1-butoxy)-phenyl]-10,15,20-tris(4-N-methylpyridiniumyl)porphyrin is shown and discussed on the grounds of their molecular structure. The comparison with 5,10,15,20-tetrakis(1-methyl-4-pyridyl)-21H,23H-porphine and its copper (II) complex is presented.