A density functional reactivity theory (DFRT) based approach to understand the interaction of cisplatin analogues with protecting agents

DFT-based reactivity and QSPR studies of platinum (IV) anticancer drugs

In the present work the influence of different axial ligands on reactivity of some selected Pt(IV) complexes with anticancer activities are investigated in both gas and solvent phases using Density Functional Theory (DFT) calculations. Calculated geometries of the complexes are in good agreement with their available X-ray data. The reactivity descriptors such as hardness, chemical potential and electrophilicity are calculated to measure stability and reactive nature of the complexes. It has been interesting to observe that the increase in the number of carbon chain of carboxylato axial ligand has no influence on reactivity of Pt(IV) complexes. Multiple linear regression analyses are performed to build Quantitative Structure Property Relationship (QSPR) models using DFT and molecular mechanics (MM+) based descriptors in gas and solvent phases. Chemical potential is found to be the most significant single descriptor to measure reduction potential of Pt(IV) complexes giving 87% correlation with experimental data. While gas phase derived descriptors are not statistically significant, inclusion of solvent medium increases the correlation of each descriptor with reduction potential and hydrophobicity of the complexes.

Modeling DNA oxidation in water

A novel set of hole-site energies and electronic coupling parameters to be used, in the framework of the simplest tight-binding approximation, for predicting DNA hole trapping efficiencies and rates of hole transport in oxidized DNA is proposed. The novel parameters, significantly different from those previously reported in the literature, have been inferred from reliable density functional calculations, including both the sugar-phosphate ionic backbone and the effects of the aqueous environment. It is shown that most of the experimental oxidation free energies of DNA tracts and of oligonucleotides available from photoelectron spectroscopy and voltammetric measurements are reproduced with great accuracy, without the need for introducing sequence dependent parameters.