A DFT investigation on interactions between asymmetric derivatives of cisplatin and nucleobase guanine

Abstract

The interactions of hydrolysis products of cisplatin and its asymmetric derivatives cis- and trans-[PtC1₂(iPram)(Mepz)] with guanine were studied using DFT methods. These interactions are dominated by electrostatic effects, namely hydrogen bond contributions and there exists a charge flow from H-atoms of ligands to the O-atoms of guanine. The replacement of NH³ moieties by larger functional groups accompanies with a moderate reaction between Ptᴵᴵ and guanine molecule, diminishing the cytotoxicity of the drug. The asymmetric and symmetric NH₂ stretching modes of complexes having strong hydrogen bond interactions are red shifted importantly as compared to complexes without presence of hydrogen bond interactions.