Thermodynamic Parameters of Cis-Platin and Trans-Platin Complexes with Guanine in Water, A DFT Study

The binding energy and Thermodynamic Parameters of cis- Platinum Di Ammino Chlorine (cis- [Pt(NH3)2Cl]+) and trans- Platinum Di Ammino Chlorine (trans- [Pt(NH3)2Cl]+) complexes with Guanine has been studied by density functional theory (DFT) calculations in water. The binding energies (Ebin) of cis- and trans-[Pt(NH3)2ClG]+ are calculated to be 79.38 kcal/mol and 74.98 kcal/mol, respectively. The binding energy (Ebin) of cis-[Pt(NH3)2ClG]+ turns out to be energetically more favorable by about 1.88 kcal/mol than the trans-[Pt(NH3)2Cl]+. At the point of thermodynamic, the formation of cis-[Pt(NH3)2ClG]+ (aq) with G (Solv) equal to -10.36 kcal/mol is more favorable than trans-[Pt(NH3)2ClG]+ (aq) with 16.21 kcal/mol.