COBALT(II) COMPLEX BINDING WITH COPOLYMER AS A PROFICIENT CATALYST FOR OXIDATION OF CATECHOL | ||||
| Al-Azhar Bulletin of Science | ||||
| Article 7, Volume 2008, Issue 12, December 2008, Page 83-94 PDF (502.35 K) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/absb.2008.10797 | ||||
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| Author | ||||
| AHMED I. HANAFY* | ||||
| Chemistry Department, Faculty of Science, Al-Azhar University, Nasr City, Cairo, Egypt | ||||
| Abstract | ||||
| The metallopolymer cobalt(II) complex of a simple pyridine- and amide-containing copolymer (CoII-P9) was prepared and characterized with IR and 1H NMR. The 1H NMR spectrum of the copolymer indicates that the average repeating unit of the copolymer P9 is vinyl pyridine:acrylamide = 5:1. The IR spectra suggest that cobalt is bound to the polymer through the pyridine nitrogen atom and the acrylamide does not participate in the binding. The oxidation of catechol by CoII-P9 in the presence of 7.5 mM H2O2 exhibits enzyme-like pre-equilibrium kinetics, yielding kcat = 0.026 ± 0.3 s–1, dissociation constant K′ = 1.9 ± 0.6 mM, and kcat /K′ = 13.7 M–1s–1. The inert 4,5-dichlorocatechol is also oxidized by CoII-P9 in absence of H2O2 to afford rate constants of kcat = (3.1 ± 0.2) × 10–4 s–1 and K′ = 0.7 ± 0.1 mM. This study has introduced a simple catalase-like system to explore the mechanism of Co(II)-centered redox chemistry and its application. | ||||
| Keywords | ||||
| Catechol; oxidase; copolymer; vinyl pyridine, inhibition | ||||
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