Synthesis and structure of a binuclear calcium nitrate coordination complex with bridging zwitterionic nicotinic acid
Abstract
The title coordination complex, bis(μ-pyridin-1-ium-3-carboxylato-κ 2 O : O ′)bis[diaquabis(nitrato-κ 2 O , O ′)calcium(II)], [Ca 2 (C 6 H 5 NO 2 ) 2 (NO 3 ) 4 (H 2 O) 4 ], was prepared from calcium nitrate and nicotinic acid in a water–ethanol solvent mixture. The asymmetric unit contains a half molecule of the complex, with the calcium atom exhibiting a coordination number of eight, forming a distorted dodecahedral geometry with a mixed-ligand environment. The μ 2 -O, O ′ bridging zwitterionic nicotinic acid molecules generate a centrosymmetric dinuclear complex. The extended structure features N—H...O, O—H...O and C—H...O hydrogen bonds, which generate a three-dimensional network. Hirshfeld surface and two-dimensional fingerprint plot analyses were performed to quantify and visualize the intermolecular interactions contributing to the overall cohesion of the structure.