Anion encapsulation and geometric changes in hepta- and hexanuclear copper(I) dichalcogeno clusters: a theoretical and experimental investigation.

Whereas stable octanuclear clusters of the type M(I)8(E(∩)E)6 (M = Cu, Ag; E(∩)E = dithio or diseleno ligand) are known for being able to encapsulate a hydride or main-group anion under some circumstances, only the related hydride-containing heptanuclear [M(I)]7(H)(E(∩)E)6 and empty hexanuclear [M(I)]6(E(∩)E)6 species have been characterized so far. In this paper we investigate by the means of theoretical calculations and experiments the viability of empty and anion-centered clusters of the type [Cu(I)]7(X)(E(∩)E)6 and [Cu(I)]6(X)(E(∩)E)6 (X = vacancy, H or a main-group atom). The theoretical prediction for the existence of anion-containing heptanuclear species, the shape of which is modulated by the anion nature and size, have been fully confirmed by the synthesis and characterization of [Cu7(X){S2P(O(i)Pr)2}6] (X = H, Br). This consistency between experiment and theory allows us to predict the stability and shape-modulated structure of a whole series of [Cu(I)]7(X)(E(∩)E)6 (X = vacancy, H, O, S, halogen) and [Cu(I)]6(X)(E(∩)E)6 (X = H, halogen) clusters.