Heteronuclear metal-metal contacts between gold(I) and group-11,-12, and-13 centers

Closed-shell interactions occur mainly for some heavy late transition metals and main-group elements. In fact, these are dispersion forces reinforced by relativistic effects and by ionic components, of which the former are maximized in heteronuclear interactions, Heteronuclear compounds containing gold(1) and group-11, -12, and -13 metals display d(10)-d(10) or d(10)-s(2) closed-shell interactions of intermediate strength relative to the homonuclear metal-metal interactions. The number of examples of gold(1)-gold(1) contacts is large, but representatives of heteronuclear gold(1)-metal contacts are still scarce. There are two general types of derivatives displaying short gold-metal distances: those with bridging ligands and those with unbridged ones, of which the latter are always the more indicative of the presence of a real bond. Derivatives featuring unsupported gold-metal bonds have been obtained mainly through reactions between basic gold(1) complexes and acid complexes, and also by encapsulation of metal centers in metallocryptands. Most derivatives with supported gold-metal bonds have been synthesized by use of C-donor ligands or ambidentate ligands. The gold-metal contacts dramatically affect the conformations and the aggregation of the molecules, and also their optical properties. Some of these derivatives are, in fact, intensely luminescent.