Crystal structure and Hirshfeld surface analysis of tetraaquabis(isonicotinamide-kappa N-1) nickel(II) fumarate

The reaction of NiCl2 with fumaric acid and isonicotinamide in a basic solution produces the title complex, [Ni(C6H6N2O)(2)(H2O)(4)](C4H2O4). The nickel(II) ion of the complex cation and the fumarate anion are each located on an inversion centre. The Ni-II ion is coordinated octahedrally by four water O atoms and two N atoms of isonicotinamide molecules. The fumarate anion is linked to neighbouring complex cations via O-water-H center dot center dot center dot O-fumarate hydrogen bonds. In the crystal, the complex cations are further linked by O-H center dot center dot center dot O, N-H center dot center dot center dot O and C-H center dot center dot center dot O hydrogen bonds, forming a three-dimensional supramolecular architecture. Hirshfeld surface analysis and two-dimensional fingerprint plots were used to analyse the intermolecular interactions present in the crystal and indicate that the most important contributions for the crystal packing are from H center dot center dot center dot O/O center dot center dot center dot H (41.8%), H center dot center dot center dot H (35.3%) and H center dot center dot center dot C/C center dot center dot center dot H (10.2%) interactions.