A spectrophotometric and thermodynamic study of the sitting-atop complex formation from reaction between free base meso-tetraarylporphyrins and zirconyl nitrate in chloroform solution

The interaction of ZrO(NO3)2·xH2O with H2t(4-X)pp, X = H, Br, Cl, CH(CH3)2, OCH3 and CH3, in chloroform produce 1:1 sitting-atop complexes. The formation constants and other thermodynamic parameters (ΔG°, ΔH° and ΔS°) for SAT complexes are obtained which directly depend on electron donation effect of the substitutent groups on the aryl rings of the porphyrins.