Spectroscopic and thermodynamic approach to the interaction of nonperipherally substituted cationic phthalocyanines with calf thymus (CT)-DNA

Novel, nonperipherally tetrasubstituted cationic metal-free and metallophthalocyanines (Zn, In) were synthesized in the present study. The binding constants, the disappearance of quenching effect of all cationic phthalocyanines on the fluorescence intensity of SYBR Green-disodium salt of deoxyribonucleic acid (DNA) from calf thymus complex, and the changes in T-m of double helix DNA with thermal denaturation profile were investigated by UV-Vis and fluorescence spectrophotometric methods. To investigate the spontaneity of the reactions between DNA and novel quaternized phthalocyanines in buffer, thermodynamic parameters were employed.