Complexation between nickel(II), cobalt(III) and hydrazones derived from pyridoxal 5′-phosphate and hydrazides of 2-,3-,4-pyridinecarboxylic acids in aqueous solution

abstract

The present work reports on stoichiometry, apparent stability constants of biologically relevant complexes of nickel(II), cobalt(III) with hydrazones derived from pyridoxal 5′-phosphate and hydrazides of 2-,3-,4-pyridinecarboxylic acids at pH 7.4, T = 25.0 °C, I = 0.25 determined using UV-Vis spectroscopy. The thermodynamic constants of some complexes formation (NiL, NiL₂, NiL₂H) were estimated. Cobalt(II) ion was found to be oxidized to cobalt(III). Co(II) and Co(III) form low-spin state complexes. Hydrazones binding ability (pL_0.5) in the medium mimicking biological ones towards Ni(II) and Co(III) was estimated.

Graphical abstract

Keywords:

• Hydrazone
• stability
• pyridoxal 5′-phosphate
• Nickel(II)
• Cobalt(III)

Acknowledgements

The equipment of the Center of Collective Use of Ivanovo State University of Chemistry and Technology and G.A. Krestov Institute of Solution Chemistry, Russian Academy of Sciences, was used to perform NMR study.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The study was carried out with the financial support of Russian Foundation for Basic Research (project 16-33-60017) and under Council on grants of the President of the Russian Federation (project 14.Z56.18.877-MK).