Molecular and electronic structure of hydrolized platinum anticancer drugs as revealed by X-ray absorption, IR, UV-Vis spectroscopies and DFT calculations

Abstract

The present study deals with the electronic structure of the bioactive anticancer drugs based on platinum(II) complexes: cisplatin PtC_l2(NH₃)₂, carboplatin PtC₆H₁₂N₂O₄ and oxaliplatin PtC₈H₁₄N₂O₄, which are being used in cancer treatment. The purpose of the work was to examine the molecular and electronic structure of platinum(II) coordination complexes when they undergo hydrolysis, which is crucial in order to better understand their antitumor properties. The density functional theory (DFT) was used to investigate the electronic structure of the platinum(II) complexes under study. The process of hydrolysis was simulated, and the structure and geometry of hydrolyzed platinum complexes were determined. The electronic structure, energy levels of occupied and unoccupied MOs and the distribution of the total and partial electron density of states (DOS) were shown and the UV-Vis and oscillation spectra of the hydrolyzed platinum(II) complexes were calculated. The theoretical calculations were verified by the experimentally obtained data by applying the method of X-ray absorption at PtL₃ edge as well as UV-Vis and IR spectroscopic techniques.