Study of the Nature of Closed-Shell Hg^II···M^I (M = Cu, Ag, Au) Interactions

Heteronuclear complexes [HgM­(o-C6H4PPh2)2]­X (M = Au, X = ClO4 (1); M = Ag, X = BF4 (2); M = Ag, X = CF3CO2 (3); M = Cu, X = Br (4)) were prepared by the treatment of [Hg­(o-C6H4PPh2)2] with one equivalent of the corresponding coinage metal salt. Their crystal structures, determined by X-ray diffraction methods, display HgII···MI (M = Au, Ag, Cu) contacts. Ab initio calculations show similar interaction energies (ca. 40 kJ·mol–1) and similar origin (dispersive forces) for these Hg···Au, Hg···Ag, and Hg···Cu interactions.