Synthesis and evaluation of catecholase activities of metal complexes of 1,4-substituted piperazine Mannich base of 4-acetamidopheno

Authors

AYOWOLE OLAOLU AYENI
GARETH MOSTYN WATKINS

DOI

10.3906/kim-1710-20

Abstract

The synthesis and characterisation including $^{1}$H and $^{13}$C NMR spectroscopy of a Mannich~base~1,4-di-(5-acetamido-2-hydroxybenzyl)piperazine~is herein reported. The Mannich reaction leading to the formation of the ligand took place at both ends of piperazine. Four metal complexes [Cu(II) and Fe(III)] including those bearing thiocyanate groups (SCN-) in N- and S-bonding modes have been studied for their abilities to mimic catecholase oxidase. All the metal complexes are catalytically active with the highest turnover rate (k$_{cat})$ recorded for complex 3. The catalytic process as monitored by $^{1}$H NMR spectroscopy (isolation of 3, 5-DTBQ) and iodometric titration revealed the formation of H$_{2}$O$_{2}$ and thus implied that the mechanism of oxidation is through the formation of a semiquinolate species.

Keywords

Mannich base, thiocyanate, isothiocyanate, catecholase activity, turnover rates

First Page

1275

Last Page

1284

Recommended Citation

AYENI, AYOWOLE OLAOLU and WATKINS, GARETH MOSTYN (2018) "Synthesis and evaluation of catecholase activities of metal complexes of 1,4-substituted piperazine Mannich base of 4-acetamidopheno," Turkish Journal of Chemistry: Vol. 42: No. 5, Article 7. https://doi.org/10.3906/kim-1710-20
Available at: https://journals.tubitak.gov.tr/chem/vol42/iss5/7