Thermally Stable Solids Based on Endohedrally Doped ZnS Clusters

Abstract

The existence of inorganic, hollow, fullerene-like ZnS clusters has been theoretically predicted and then recently confirmed experimentally. These clusters were observed to trap alkali metals and halogens because the ionization energies (IE) of alkali metals are very similar to the electron affinities (EA) of halogens. This opens the possibility of forming molecular solids composed of these fullerene building blocks because the energy released due to the difference between the IE and EA would be very small. Herein we have focused on assembling bare Zn(12)S(12) and endohedral X@Zn(12)S(12)-Y@Zn(12)S(12) dimers (X = Na, K; Y = Cl, Br) by considering the square-faces-square orientation of every two adjacent clusters, which leads to a fcc cubic crystal structure in the solid. The structures were fully optimized in all cases, and their thermal stability was confirmed by ab initio thermal molecular dynamics calculations. The optimum lattice parameter of the solids was found to be around 13.8 A, which corresponds to distances of about 2.5 A between monomers, which is typical of covalent Zn-S bonds. The resulting solids are nanoporous materials similar to B(12)N(12). Due to their nanoporous structure, these zeolite-shaped solids could be used in heterogeneous catalysis and as storage materials and molecular sieves.

Theoretical prediction of low-density nanoporous frameworks of zinc sulfide based on ZnnSn(n = 12, 16) nanocaged clusters

“…In this work, our calculated optimum lattice parameter is found to be 13.25 Å with a distance of 2.546 Å between monomers. It is obvious that the lattice parameter we obtained is a little smaller than that of Matxain et al 62 The differences in lattice parameters may be attributed to bond lengths of the intermonomer Zn-S bonds. We found that each monomer in the structure 12-3 has two types of Zn-S bonds, a longer one (2.458 Å) in four-membered rings and the other shorter one (2.378 Å) connecting the neighboring fourmembered rings, which are larger than those of isolated monomers.…”

“…This structural framework was also investigated by Matxain et al in a study on thermally stable solids based on endohedrally doped ZnS clusters. 62 Since the centers of Zn 12 S 12 cages favor the bulk fcc structure, they predicted that the structure of the characterized solid has a cubic unit cell with lattice parameters of Fig. 5 The optimized stable structures of frameworks assembled by Zn 16 S 16 clusters.…”

Second-Row Transition-Metal Doping of (ZniSi), i = 12, 16 Nanoclusters: Structural and Magnetic Properties

“…Therefore, assemblies of small clusters would lead to AF materials, while assemblies of large clusters would lead to F materials, being the AF coupling close in energy. Moreover, considering the Ag-Ag distances in these dimers, along with related studies on other encapsulated X@ZnS and X@CdS assemblies [44,45], we suggest that the Ag-Ag distances would remain quite similar in the solid compared to the dimers.…”

Tuning the electronic and optical properties of the sphalerite by adsorbing halogen and alkali metals

“…The stability of ZnS nanostructures has also been reported by several other experimental and simulation studies. In [46], the stability of endohedrally doped ZnS clusters has been confirmed by ab initio simulations. In [47], a wet‐chemical precipitation method is optimised for the synthesis of ZnS nanocrystals doped with Cu+ and halogen.…”