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

Abstract

Mixed-ligand coordination compounds containing neutral nicotinamide and monoanionic diphenate organic 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 complex 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. Accordingly, 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.