Molecular structures and spectroscopic studies of cationic metal–methylisonicotinate complexes with saccharinate counterions

The crystal structures of [Co(methylisonicotinate)2(H2O)4](saccharinate)2 and [Ni(methylisonicotinate)2(H2O)4](saccharinate)2 complexes have been synthesized and characterized by spectroscopic, EPR and X-ray diffraction techniques. The XRD data have indicated that both the Co(II) and Ni(II) ions lie on an inversion center, having distorted octahedral coordination through four aqua ligands composing the basal plane and two trans nitrogen atoms from the monodentate methylisonicotinate ligands occupying the axial sites. The EPR spectra of these complexes have been studied in the temperature range between 113 and 300 K in three mutually perpendicular planes. The EPR spectral results were discussed and compared in relation with the other compounds containing saccharinate and methylisonicotinate complexes.

Graphical abstractA partial view of the packing of cobalt(II) complex, showing hydrogen bonding interactions as dashed lines.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Magnetic properties of the metal complexes are characterized by EPR technique. ► The Co2+ and Ni2+ ions are coordinated four aqua ligands and two nitrogen atoms. ► The Cu2+ ion enters instead of divalent Co2+ or Ni2+ ions.