Effect of the charge state on bare monoicosahedral [Au13]z+ and diphosphine-protected Au13 clusters [Au13(dmpe)5Cl2]z+: structural, electronic and vibrational DFT studies

In this paper a GGA-PBE study of [Au-13](z+) bare clusters (z = +3, +5) and diphosphine protected [Au-13(dmpe)(5)Cl-2](z+) clusters (z = 1, 3) is presented. To explore the application of the [Au-13((P(CH3)(2)CH2)(2))(5)Cl-2](3+) cluster as a cisplatin carrier, we have evaluated the adsorption energy of one cisplatin dimer interacting with the complex (0.53 eV). By considering a 1+ charge state, we have determined one cluster featuring a slight reduced HOMO-LUMO gap, with an inner Au-13 core heavily distorted (strong charge effects). It is found that the filling/distribution of the superatomic energy levels is affected by the addition of two electrons to the [Au-13(dmpe)(5)Cl-2](3+) cluster with a reduction of its symmetry (C-1 point group). In addition, the calculated IR and Raman spectra of charged [Au-13(dmpe)(5)Cl-2](z+) clusters allow distinguishing them.