Density functional study of aurophilic interaction in [X(AuPH3)(2)(+)](2) (X = F, Cl, Br, I)

Several closed-shell systems [X(AuPH3)(2)(+)](2) (X = F, Cl, Br, I) have been theoretically investigated by using density functional theory (DFT) and second order Moller-Plesset (MP2) methods in order to study the intermolecular aurophilic interaction. We studied the geometry of the structures, natural bond orbital (NBO) populations and the HOMO-LUMO gap of the title compounds. Experimental structural parameters of the title compounds were reproduced at the X alpha level. The predicted experimental Au-F-Au and P-Au-F angles are 119.1 +/- 0.5 degrees and 178.4 +/- 0.5 degrees, respectively. The intermolecular aurophilic interaction energy is decomposed and analyzed. The chemical deformation electronic density is obtained to analyze the intermolecular interaction.