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

View : 17 | Download : 5

Publication Date : 0000-00-00

Article Type : Research Paper

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-insert ignore into journalissuearticles values(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 [Cuinsert ignore into journalissuearticles values(II); and Feinsert ignore into journalissuearticles values(III);] including those bearing thiocyanate groups insert ignore into journalissuearticles values(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 insert ignore into journalissuearticles values(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 insert ignore into journalissuearticles values(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