Halide ion-driven self-assembly of Zn(ii) compounds derived from an asymmetrical hydrazone building block : a combined experimental and theoretical study

Three Zn(n) complexes, namely mononuclear derivatives [Zn(H2L)(2)I-2]center dot 2CH(3)OH (1) and [Zn(H2L)(2)Br-2]center dot 2CH(3)OH (2) and a tetranuclear cyclic compound [Zn-4(H2L)(4)Cl-8]center dot 4CH(3)OH (3) {H2L = p-hydroxybenzaldehyde isonicotinoylhydrazone}, were synthesized using a self-assembly method and fully characterized. Characterization included theoretical methods and single crystal X-ray diffraction. The molecular structures of compounds 1-3 demonstrate the effect of halide ions and the binding mode of H2L on self-assembly. The arrangement of the packing patterns in 1-3 is well explained by various types of non-covalent interactions. Notably, several types of strong H-bonding, C-H center dot center dot center dot O, and pi center dot center dot center dot pi interactions were also observed, which assist in the formation of 3D supramolecular networks. In the isostructural compounds 1 and 2, a tripod type H-bonding interaction of H2L with the methanol molecules of crystallization was observed. Furthermore, the terminal halide ligands exert H-bonding interactions with the -OH/-NH and -CH moieties of H2L. In all compounds, the supramolecular 3D networks, driven by strong H-bonding interactions, were simplified by topologial analysis. This showed a 6-connected framework with a unique topology in 1 and 2, and an 8-connected framework with bcu topology in 3 (the latter is composed of cyclic tetrazinc(II) cluster units with 2M4-1 topology). In addition, the discussion on coordination geometries and non-covalent interactions was also supported using Hirshfeld surface analysis and DFT calculations.

from #MedicinebyAlexandrosSfakianakis via xlomafota13 on Inoreader http://ift.tt/2qyNCIz
via IFTTT