The cubic ZnS structure type and the size-dependent properties of related nanoparticles are of both fundamental and technological importance. Yet, it remains a challenge to synthesize large atom-precise clusters of this structure type. Currently, only supertetrahedral clusters with 4, 10, 20, and 35 metal sites (denoted as T2, T3, T4, and T5, respectively) are known. Because the synthesis of T5 in 2002, numerous synthetic efforts targeting larger clusters only resulted in T2-T5 clusters in various compositions and intercluster connectivity, with T6 (56 metal and 84 anion sites) being elusive. Here, we report the so-far largest supertetrahedral cluster (T6, [ZnInS]). New T6 clusters can serve as the host matrix for optically active centers. Mn-doped variants of T4 and T6 have also been made, allowing the investigation of site-dependent Mn emission. The results lead to the elucidation of the mechanism regulating Mn emission via size-dependent crystal lattice strain and provide new insight into Mn-doping chemistry in cluster-based chalcogenides at the atomic level.

In-depth investigations of the specific ion-responsive characteristics based on 2:1 "sandwich" structures and effects of crown ether cavity sizes on the metal-ion/crown-ether complexation are systematically performed with a series of PNIPAM-based responsive copolymers containing similar contents of crown ether units with different cavity dimensions (12-crown-4 (12C4), 15-crown-5 (15C5), 18-crown-6 (18C6)). The lower critical solution temperature (LCST) values of copolymers in deionized water shift to lower temperatures gradually when the crown ether contents increase or the ring sizes decrease from 18C6 to 12C4. With increasing the concentrations of alkali metal ions (Na(+), K(+), Cs(+)) or the contents of pendent crown ether groups, the copolymers with different crown ether cavity sizes exhibit higher selectivity and sensitivity to corresponding cations. Importantly, the ion sensitivities of the copolymers in response to corresponding alkali metal ions increase dramatically with an increase in the crown ether cavity size. Interestingly, a linear relationship between the crown ether cavity size and the diameter of corresponding cation for the formation of stable 2:1 "sandwich" complexes is found for the first time, from which the size of metal ions or other guests that able to form 2:1 "sandwich" complexes with crown ethers can be deduced. The results in this work are valuable and useful for further developments and practical applications of various crown-ether-based smart materials.

Reported here is a new open-framework metal chalcogenide containing extra-large 36-ring channels. This compound has a 3-connected etc topology by regarding supertetrahedral T2 clusters as the structural nodes. It has a very low framework density (3.4 tetrahedra per 1000 Å) with each framework cation participating in three 3-rings. The organic cations within its intersecting channels can be partially exchanged out by Cs ions with the preservation of its framework structure.

Reported here are three new In–Se open frameworks with unique polyselenide ion as linker. Single-crystal X-ray diffraction analyses demonstrate that supertetrahedral Tn (n = 2, 3) clusters serving as secondary building units in these compounds are connected via polyselenide ligands to form the interrupted or elongated diamond topologies. UV–vis absorption analysis and photoelectric response measurements indicate that these In–Se frameworks retain semiconductor properties, making them potential candidates in photocatalytic applications.