Coordination preferences of NNO and NNS Schiff base ligands with Co(III) complexes: Synthesis, characterization and DFT calculation

Two Co(III) complexes with condensation product of thiosemicarbazide and 2-acetylthiazole ( HL 1 ligand, ( E )-2-(1-(thiazol-2-yl)ethylidene)hydrazine-1-carbothioamide) and the condensation product of 2-acetylpyridine and Girard's P reagent ( HL 2 Cl ligand, ( E )-1-(2-oxo-2-(2-(1-(pyridin-2yl)ethylidene)hydrazinyl)ethyl)pyridin-1-ium chloride) have been synthesized and characterized based on the results of single-crystal X-ray diffraction, NMR and IR spectroscopy and elemental analysis. Cobalt(III) complex with HL 1 ligand, [Co( L 1 ) 2 ]BF 4 center dot H 2 O ( 1 ), is bis octahedral complex in which two deprotonated ligand molecules coordinate in a mer arrangement through two NNS sets of donor atoms. In cobalt(III) complex with HL 2 Cl, [Co( L 2 )(N 3 ) 3 ] ( 2 ), the ligand is coordinated in deprotonated, formally neutral, form to Co(III) ion in tridentate fashion through NNO set of donor atoms, and the other three coordination sites of a monokis octahedron are occupied by meridionally coordinated azide anions. DFT calculations were performed to elucidate coordination preferences of these ligands toward Co(III) ion. (c) 2022 Elsevier B.V. All rights reserved.

Automated summary

Two Co(III) complexes with condensation products of thiosemicarbazide and 2-acetylthiazole and the condensation product of 2-acetylpyridine and Girard's P reagent have been synthesized and characterized. The coordination preferences of these ligands towards Co(III) ion have been investigated using single-crystal X-ray diffraction, NMR, IR spectroscopy, and elemental analysis. DFT calculations were also performed to further elucidate the coordination modes of the ligands.