Chalcogenide-centered Cu11 clusters heteroleptically passivated by dichalcogenolates and iodo ligands

Abstract

Halide ligands can serve as auxiliary ligands for the dichalcogenolates ligands, facilitating the formation of novel chalcogen-centered copper clusters. This report presents three chalcogenide-centered copper clusters, namely [Cu₁₁S{S₂CNⁿBu₂}₆(I)₃] (1), [Cu₁₁Se{Se₂CNⁿPr₂}₆(I)₃] (2), and [Cu₁₁Se{Se₂CNⁱBu₂}₆(I)₃] (3). Cluster 1 was isolated from the reaction of [Cu(CH₃CN)₄](BF₄) with dithiocarbamate (dtc) ligands, specifically dtc = {S₂CNⁿBu₂}⁻, alongside [NBu₄I], in the presence Na₂S₂O₃ as the sulfide source. Clusters 2 and 3 are prepared from diselenocarbamate (dsec) ligands, from which the selenide anion is generated in situ. The structures are characterized using single X-ray diffraction, which demonstrated that clusters 1–3 are iso-structural and feature a chalcogenide-centered Cu₁₁ 3,3,4,4,4-pentacapped trigonal prism surrounded by six dichalcogelates ligand, co protected by iodo ligands. The structural study demonstrated that the central chalcogenide (S²⁻ and Se²⁻) in clusters 1–3 enhances the host–guest interaction, with the order of effectiveness being S < Se. Furthermore, the replacement of dichalcogenolate ligand, dtc with dsec, elongates metallic interactions within the copper host cage. The structural characteristics of clusters 1–3 demonstrate notable similarities, providing a basis for comparing the inverse coordination of chalcogenide-centered clusters protected by various dichalcogenolates and iodide ligands, which affect the host–guest distances within the Cu₁₁ framework.