Potential antitumor gold drugs: DFT and XANES studies of local atomic and electronic structure

Geometry structure optimization of the potential antitumor agent Au(bipy)(OH)₂ was carried out by means of density functional theory simulations. The experimental Au L₃-edge X-ray absorption near edge structure (XANES) spectrum of Au(bipy)(OH)₂ was obtained. The theoretical Au L₃-XANES spectra of the gold(III) complex Au(bipy)(OH)₂ were simulated using both the self-consistent real-space full multiple scattering theory within the muffin-tin approximation for the potential shape and the full-potential finite difference method. The comparison of the theoretical spectra with the experimental XANES is discussed. The exact local atomic structure of gold complex Au(bipy)(OH)₂ has been defined by two independent ab initio methods.