The Noncovalent Interaction in Dinuclear Bridged Gold(I) Complexes: A Theoretical Study

We present a study of the cooperative nature of the forces dominating the interaction between gold atoms and aryl-aryl stacking. For this purpose, we modeled a series of complexes of the type dpm(AuR)₂ (dpm= bis(phoshino)methane; R = -C₆H₅, -C₆F₅, -C₆Cl₅, and -Cl). The models were calculated at the MP2, CCSD(T), and DFT-D3(BJ) (PBE and TPSS) levels of theory. The results show Au-Au and aryl-aryl stacking distances associated with noncovalent interactions. Also, the Wiberg indices, NBO, NCI, and QTAIM analyses exposed a low-density character between the gold atoms and aryl-aryl stacking, revealing that this contribution explains the stability of the complexes via dispersive interactions. Finally, the absorption spectra obtained are comparable with the experimental ones, and the orbitals obtained demonstrate that after the transitions, the orbitals are delocalized between the gold atoms and the vertex atoms of the molecules.