Zero- and two-dimensional organization of tetrahedral cadmium chalcogenide clusters with bifunctional covalent linkers

Few examples are known in which chalcogenide clusters are assembled with organic ligands into crystallographically ordered covalent superlattices even though molecular crystals of such clusters have been known for decades. Here by using bifunctional organic ligands as the organizing force, semiconducting tetrahedral chalcogenide clusters, Cd32S14(SPh)(36), have been assembled into two-dimensional layers. In addition, a dimeric unit consisting of two core-shell-like C17Se4(SPh)(26) clusters bridged by two organic ligands has also been synthesized. In these inorganic-organic hybrid assemblies, chalcogenide clusters and bifunctional organic ligands are joined together through metal-ligand coordination bonds. A key structural feature is the presence of two organic bridging ligands between the same two clusters ( the double-bridging mode). This work demonstrates the feasibility of creating organized nanocluster-ligand superstructures through synthetic design of molecular clusters or bridging ligands.