Synthesis and structure of di-aqua-bis-(nicotinamide-κ)bis-(nitrato-κ ,')calcium(II).

The title complex, [Ca(NO)(CHNO)(HO)], crystallizes with an eight-coordinate Ca ion in a distorted trigonal-dodeca-hedral coordination environment. The metal ion is coordinated to two nicotinamide ligands their carbonyl O atoms, two bidentate nitrate anions and two water mol-ecules. The nicotinamide ligands adopt a nearly geometry, while the nitrate anions and aqua ligands are arranged in a pseudo- fashion. In the crystal, a three-dimensional supra-molecular framework is constructed through N-H⋯O and O-H⋯O hydrogen bonds involving water, nitrate, and nicotinamide functional groups, reinforced by offset π-π stacking inter-actions between nearly parallel pyridine rings [centroid-to-centroid distance = 3.783 (2) Å]. A Hirshfeld surface analysis revealed that the inter-molecular inter-actions are dominated by O⋯H/H⋯O (42.3%) and H⋯H (26.2%) contacts, corresponding to classical hydrogen bonding and van der Waals forces, respectively.