Crystal structures of two nickel compounds comprising neutral NiII hydrazone complexes and di-carb-oxy-lic acids.

Takumi Nakanishi,Osamu Sato

doi:10.1107/s2056989016020326

Takumi Nakanishi, Osamu Sato

Open Access

https://doi.org/10.1107/s2056989016020326

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Abstract

Two isostructural NiII compounds, bis-{N-[1-(pyridin-2-yl-κN)eth-ylidene]pyridine-4-carbohydrazonato-κ2N',O}nickel(II)-2,5-di-chloro-terephthalic acid (1/1), [Ni(C13H11N4O)2](C8H4Cl2O4), and bis-{N-[1-(pyridin-2-yl-κN)eth-ylidene]pyridine-4-carbohydrazonato-κ2N',O}nickel(II)-2,5-di-bromo-terephthalic acid (1/1), [Ni(C13H11N4O)2](C8H4Br2O4), were synthesized and their crystal structures determined. The pair of N,N',O-tridentate N-[1-(pyridin-2-yl-κN)eth-yl]pyridine-4-carbohydrazonate L ligands result in a cis-NiO2N4 octa-hedral coordination sphere for the metal ions. The asymmetric units consist of two half-mol-ecules of the di-carb-oxy-lic acids, which are completed by crystallographic inversion symmetry. In the respective crystals, the 2,5-di-chloro-terephthalic acid (H2Cl2TPA, 1-Cl) mol-ecules form zigzag hydrogen-bonded chains with the [Ni(L)2] mol-ecules, with the hydrogen-bond distances in 1-Br slightly longer than those in 1-Cl. The packing is consolidated by aromatic π-π stacking between the di-carb-oxy-lic acid mol-ecules and terminal pyridine rings in [Ni(L)2] and short halogen-halogen inter-actions are also observed. The qualitative prediction of the H-atom position from the C-N-C angles of the terminal pyridine rings in L and the C-O distances in the carboxyl groups show that 1-Cl and 1-Br are co-crystals rather than salts.

Highlights

[Ni(C13H11N4O)2](C8H4Br2O4), were synthesized and their crystal structures determined
The asymmetric units consist of two half-molecules of the dicarboxylic acids, which are completed by crystallographic inversion symmetry
Metal complexes based on 2-acetylpyridine isonicotinoylhydrazone (HL) have attracted considerable attention for the construction of supramolecular materials (Servati Gargari et al, 2015; Valipour et al, 2016) and as functional complexes for applications in various biochemical fields (Ababei et al, 2012; Chang, Jia, Xu, Xu et al, 2015; Chang, Jia, Xu, Wu et al, 2015)

Summary

Chemical context

Metal complexes based on 2-acetylpyridine isonicotinoylhydrazone (HL) have attracted considerable attention for the construction of supramolecular materials (Servati Gargari et al, 2015; Valipour et al, 2016) and as functional complexes for applications in various biochemical fields (Ababei et al, 2012; Chang, Jia, Xu, Xu et al, 2015; Chang, Jia, Xu, Wu et al, 2015). The precursors of HLs and related hydrazone ligands have been used in the design of complexes stabilized by strong hydrogen bonds (Lemmerer et al, 2010; Grobelny et al, 2011; Aakeröy et al, 2012; Cherukuvada & Nangia, 2012; Aitipamula et al, 2009) and spin-crossover complexes (Hill et al, 2010; Zhang et al, 2010). It is possible that metal complexes with HL ligands could be applied in the design of various functional materials.

Structural commentary

Supramolecular features

Refinement