The Thermodynamic Studies of the Molecular Interactions of Diphenyltin(IV) Dichloride and Dibromide with meso-Tetraarylporphyrins

The thermodynamic parameters for interactions of Ph2SnCl2 and Ph2SnBr2 with para-substituted meso-tetraphenylporphyrins (H2T(4-X)PP; X = OCH3, CH3, H, Cl) have been studied. The formation constants have been calculated using UV-Vis titration spectra and computer SQUAD program. The adducts show the composition 2:1 of Ph2SnX2 to porphyrin. Formation constants decreased with decreasing electron donation of porphyrins and with decreasing electron withdrawing property of X group on the diphenyltin compound, as follow: H2T(4-OCH3)PP > H2T(4-CH3)PP > H2TPP > H2T(4-Cl)PP; and Ph2SnCl2 > Ph2SnBr2.