Study on electronic properties, thermodynamic and kinetic parameters of the selected platinum(II) derivatives interacting with guanine.

Interaction of hydrated forms of several potential anticancer agents (PtCl(diaminocyclohexane), trans-[PtCl(NH)(thiazole)], cis-[PtCl(NH)(piperidine)], and cis-PtCl(NH)(cyclohexylamine) complexes) with guanine are explored and compared with an analogous interaction of cisplatin. Basic electronic properties, binding and stabilization energies are determined and energy profiles for the aquation reaction are estimated at the B3LYP/6-311++G(2df,2pd) level of theory. It is found that the substitution reaction is an exothermic and exergonic process with ΔG slightly less negative than -20kcal/mol. The largest energy release occurs for PtCl(HO)(diaminocyclohexane) complex. The rate constants for the Pt(II) complexes in the chloro- and hydroxo-form are compared and an impact of the ligand in the trans position to water is discussed.