Mother structures related to the hexagonal and cubic close packing in Cu24 clusters: solvent-influenced derivatives

Abstract

Compound 1 [Cu24(m BDC)24(DMF)20(H2O)4]• 24DMF•40H2O (m-BDC is 1,3-benzenedicarboxylate and DMF is N,N-dimethylformamide) has been synthesized and structurally characterized by X-ray diffraction. It consists of Cu24-clusters arranged in such a way that 12 dimers are connected through m-BDC ligands. The clusters exhibit an internal cavity where crystallization molecules of DMF and water are located. Additionally, there are guest DMF and water molecules in the voids generated by the 3D packing of the Cu24-clusters. The thermal stability of compound 1 has been also characterized, concluding that hydrogen bonds between solvent molecules are responsible for the robustness of the network. Compound 1 is similar to other seven compounds found in literature. This work is focused on the crystallochemical comparison of these compounds, which concludes that there are two mother structures related to the hexagonal and cubic close packing of polyhedra, respectively. Derivative compounds are produced by the presence of different solvent molecules (differences affecting both the nature and the number of the guest molecules).