Role of Dispersion in Metallophilic Hg···M Interactions (M = Cu, Ag, Au) within Coinage Metal Complexes of Bis(6-diphenylphosphinoacenaphth-5-yl)mercury

The previously reported
bis­(6-diphenylphosphinoacenaphth-5-yl)mercury (1) was
used as ligand for the preparation of the copper­(I) complexes, 1·CuCl and [1·Cu­(NCMe)]­BF4, which were characterized by multinuclear NMR spectroscopy and X-ray
crystallography. DFT calculations employing topological analysis
of the electron and electron pair densities within the AIM and ELI-D
space-partitioning schemes revealed significant metallophilic Hg···Cu
interactions. Evaluation of noncovalent bonding aspects according
to the noncovalent interaction (NCI) index was applied not only for
the Cu complexes 1·CuCl and [1·Cu­(NCMe)]­BF4 but also for the previously reported Ag and Au complexes,
namely, [1·MCl] (M = Ag, Au) and [1·M­(NCMe)n]+ (M = Ag, n = 2; M = Au, n = 0), and facilitated
the assignment of attractive dispersive Hg···M interactions
with the Hg···Cu contacts being comparable to the Hg···Ag
but weaker than the Hg···Au interactions. The localization
of the attractive noncovalent bonding regions increases in the order
Cu < Ag < Au.