Structural, magnetic and theoretical study of mononuclear nickel(II) and cobalt(II) compounds of a benzimidazole thiobutanoic acid derivative

• Antiferromagnetic coupling in mononuclear cobalt(II) and nickel(II) compounds.
• DFT calculations showed magnetic pathways through non-covalent interactions.
• Octahedral coordination compounds of 4-(benzimidazol-2-yl)-3-thiabutanoic acid.
• Tridentate ligand with N, S and O coordination sites.

A structural, magnetic and theoretical study of the mononuclear octahedral cobalt(II) and nickel(II) coordination compounds with the tridentate ligand, 4-(benzimidazol-2-yl)-3-thiabutanoic acid (Hbztb), was performed. At low temperature, both compounds present weak antiferromagnetic couplings via intermolecular interactions. In the [Co(bztb)2]·H2O compound, intermolecular hydrogen bonding between the benzimidazolic nitrogen atom and the neighboring carboxylic oxygen contribute to the magnetic pathway for the coupling between the cobalt(II) mononuclear complexes. Whereas in [Ni(bztb)2]·3H2O, two nickel(II) compounds are linked by non-covalent interactions through water molecules, [(Ni(bztb)2⋯(H2O)3⋯Ni(bztb)2], which play an important role on the super-exchange magnetic coupling contributing to the magnetic MO. The magnetic behavior of both coordination compounds was analyzed by DFT theoretical calculations.

A structural, magnetic and theoretical study of two mononuclear cobalt(II) and nickel(II) coordination compounds, with the tridentate NSO ligand, 4-(benzimidazol-2-yl)-3-thiabutanoic acid (Hbzta), was carried out. Both compounds presented weak antiferromagnetic couplings. This magnetic behavior is due to non-covalent interactions: in the Co2+ complex, hydrogen bonding between two mononuclear compounds; and in the case of the Ni2+ compound, three intermolecular water molecules are participating in the magnetic MO. The magnetic behavior of both complexes was analyzed by DFT theoretical calculations.Figure optionsDownload as PowerPoint slide