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Cobalt(II), Zinc(II), Iron(III), and Copper(II) Complexes Bearing Positively Charged Quaternary Ammonium Functionalities: Synthesis, Characterization, Electrochemical Behavior, and SOD Activity
Author(s) -
Stojičkov Marko,
Sturm Sabrina,
Čobeljić Božidar,
Pevec Andrej,
Jevtović Mima,
Scheitler Andreas,
Radanović Dušanka,
Senft Laura,
Turel Iztok,
Andjelković Katarina,
Miehlich Matthias,
Meyer Karsten,
IvanovićBurmazović Ivana
Publication year - 2020
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.202000415
Subject(s) - chemistry , square pyramidal molecular geometry , reactivity (psychology) , electrochemistry , redox , copper , inorganic chemistry , aqueous solution , octahedral molecular geometry , lability , zinc , crystallography , cobalt , ligand (biochemistry) , metal , medicinal chemistry , crystal structure , organic chemistry , medicine , biochemistry , alternative medicine , receptor , electrode , pathology
We have synthesized and characterized Co(II) ( 1 ), Zn(II) ( 2 ), Fe(III) ( 3 ) and Cu(II) ( 4 ) complexes of 2,2'‐[2,6‐pyridinediylbis(ethylidyne‐1‐hydrazinyl‐2‐ylidene)]bis[ N,N,N ‐trimethyl‐2‐oxoethanaminium] dichloride ( H 2 L Cl 2 ) by NMR, IR, and X‐Band EPR spectroscopy, respectively, as well as by single‐crystal X‐ray structural analysis. H 2 L Cl 2 belongs to the class of diacetylpyridine bis(hydrazone) ligands and bears two positively charged quaternary ammonium functionalities. The complexes 1 – 3 possess a pentagonal‐bipyramidal geometry, whereas 4 has square‐pyramidal geometry. Redox reactivity and SOD activity of the complexes was studied by means of electrochemical measurements in aqueous‐buffer and DMF or DMSO solutions, respectively, as well as by stopped‐flow measurements. Complexes 1 – 3 do not have SOD activity, whereas 4 exhibits a high catalytic rate constant for the superoxide dismutation, k cat = 1.73 × 10 7 m –1 s –1 (in MOPS buffer solution of pH = 7.4). The results were discussed in terms of complex redox potentials, electrostatic interactions and their spatial distribution, kinetic lability of metal centers, and stability of peroxo intermediates, respectively.