Matxain Jon M, Piris Mario, Lopez Xabier, Ugalde Jesus M
Kimika Fakultatea, Euskal Herriko Unibertsitatea and Donostia International Physics Center, P.K. 1072, 20080 Donostia, Euskadi, Spain.
Chemistry. 2009;15(20):5138-44. doi: 10.1002/chem.200802472.
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.
无机、空心、富勒烯状硫化锌团簇的存在已在理论上得到预测，最近又通过实验得到证实。观察到这些团簇能捕获碱金属和卤素，因为碱金属的电离能（IE）与卤素的电子亲和能（EA）非常相似。这为形成由这些富勒烯结构单元组成的分子固体提供了可能性，因为电离能和电子亲和能之间的差异所释放的能量会非常小。在此，我们通过考虑每两个相邻团簇的面 - 面正方形取向，专注于组装裸的Zn₁₂S₁₂和内包合物X@Zn₁₂S₁₂ - Y@Zn₁₂S₁₂二聚体（X = Na、K；Y = Cl、Br），这会在固体中形成面心立方晶体结构。在所有情况下，结构都进行了完全优化，并且通过从头算热分子动力学计算证实了它们的热稳定性。发现固体的最佳晶格参数约为13.8 Å，这对应于单体之间约2.5 Å的距离，这是共价Zn - S键的典型距离。所得固体是类似于B₁₂N₁₂的纳米多孔材料。由于它们的纳米多孔结构，这些沸石形状的固体可用于多相催化以及作为存储材料和分子筛。
