The Largest Supertetrahedral Oxychalcogenide Nanocluster and Its Unique Assembly.

Supertetrahedral oxychalcogenide T n nanoclusters (NCs, n denotes the number of metal-chalcogen layers) integrate chemically distinct but ordered oxygen and chalcogen sites in zinc-blend-type "quantum dots". They therefore offer a new level of control over various properties of semiconducting materials. So far, few such structures are known, and the cluster size is also limited to only T4 with 20 metal sites. Herein, we report an unusual oxysulfide T5 nanocluster with 35 metal sites. It has unprecedented In-O@In-S "core-shell" nanostructure and is also the largest supertetrahedral oxychalcogenide NC. Through cocrystallization, we further demonstrate that such oxychalcogenide NCs can be assembled to form multidimensional structures. In addition to N-donor imidazolates that help to form a 3-D structure with chiral quartz net, the O-donor benzenetricarboxylate (BTC) has also been found to successfully organize such T5 NCs. It is worth noting that no carboxylate ligands have been shown earlier for assembling chalcogenide clusters, despite their prevalence in MOFs. Given the wide availability of O-donor ligands, this work introduces a versatile platform with promise for a new generation of semiconducting inorganic-organic hybrid materials.