Thermodynamic Investigation of the Molecular Interactions of 4-Nitrophenol with Free-Bases meso-Tetraarylporphyrins

The molecular interactions of 4-Nitrophenol (4NP) with free-base meso-tetraarylporphyrins (H2T(4-X)PP; X = OCH3, CH3, H,Cl) have been studied. The formation constants and other thermodynamic parameters were calculated by using UV-Vis spectrophotometry titration results. The formation constants show the following trend relative to X substituent of porphyrins: H2T(4-CH3O)PP > H2T(4-CH3)PP > H2TPP > H2T(4-Cl)PP