New mixed ligand complexes of alkaline earth metal cations containing nicotinamide and diphenic acid. Synthesis and structural properties

Mixed-ligand coordination compounds containing neutral nicotinamide and monoanionic diphenate or-ganic molecules of alkaline earth metal cations, Mg2 + (C40H38MgN4O14) ( I ), Ca2 + (C40H34CaN4O2) ( II ), Sr2 +(C40H34N4O2Sr) ( III ) and Ba2 +(C40H34BaN4O2) ( IV ) were synthesised. Chemical composition analysis, single crystal XRD, spectroscopic, and thermal analysis methods were used to determine the structural properties of the compounds obtained. According to the data obtained from a single-crystal XRD analysis of the Mg2 + complex, the coordination environment of the metal cation was surrounded by four aqua and two nicotinamide ligands to form a distorted octahedral geometry. The charge balance of the com-plex sphere was provided by two diphenate ligands placed mono-anionically outside the coordination sphere. The structure is a salt-type complex. Since crystals suitable for single crystal structure analysis of other metal cations complexes ( II, III and IV ) could not be formed, the structural properties were tried to be explained by chemical composition analysis, spectroscopic, and thermal analysis methods. Accord-ingly, it is found that the coordination circles of metal cations are octahedral and all ligands (two aqua, two neutral nicotinamide, and two monoanionic-double-toothed diphenate) coordinate with the metal in the coordination sphere. The geometries of the complexes are detected to be of distorted cubic structure. (c) 2022 Published by Elsevier B.V.