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 MI8(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 [MI]7(H)­(E∩E)6 and empty hexanuclear [MI]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 [CuI]7(X)­(E∩E)6 and [CuI]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(OiPr)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 [CuI]7(X)­(E∩E)6 (X = vacancy, H, O, S, halogen) and [CuI]6(X)­(E∩E)6 (X = H, halogen) clusters.