- Turkish Journal of Chemistry
- Vol: 42 Issue: 5
- Synthesis and evaluation of catecholase activities of metal complexes of 1,4-substituted piperazine ...
Synthesis and evaluation of catecholase activities of metal complexes of 1,4-substituted piperazine Mannich base of 4-acetamidophenol
Authors : Ayowole Olaolu Ayeni, Gareth Mostyn Watkins
Pages : 1275-1284
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Publication Date : 9999-12-31
Article Type : Makaleler
Abstract : The synthesis and characterisation including 1 " role="presentation"> 1 1 ^{1} H and 13 " role="presentation"> 13 13 ^{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 c a t ) " role="presentation"> c a t ) c a t ) _{cat}) recorded for complex 3 . The catalytic process as monitored by 1 " role="presentation"> 1 1 ^{1} H NMR spectroscopy (isolation of 3, 5-DTBQ) and iodometric titration revealed the formation of H 2 " role="presentation"> 2 2 _{2} O 2 " role="presentation"> 2 2 _{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