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.