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 Tm 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.