Kinetics and Mechanism of the Catalysis of the Decomposition of Hydrogen Peroxide by Schiff Base Complexes of Copper(II).

<p>Spectroscopic studies have been used to describe the mechanism of the decomposition of hydrogen peroxide by solutions of a dimeric Cu(II) complex of a dissymetric Schiff base, [CuSALAD]₂.H₂O, and imidazole or methyl substituted imidazoles, B, which form monomeric CuSALAD.B₂ complexes, in aqueous ethanol solvent. Freezing point depression and vapor pressure lowering studies were carried out to confirm the dimeric nature of the [CuSALAD]₂.H₂O complex that had been previously reported. The stoichiometry of the [CuSALAD]₂.H₂O-imidazole equilibrium was extensively studied pointing to a 1:4 stoichiometry. The CuSALAD.B₂ adducts exhibited certain catalytic properties that mimic those of catalase enzymes. The different imidazoles were buffered to acidic, neutral and basic pH media in order to investigate the pH effects of this reaction. Two charge transfer (CT) bands were observed near 420 and 450 nm upon addition of hydrogen peroxide to CuSALADB₂ solutions, and were associated with two proposed intermediates (CuBOOH and CuBOOCu). A mechanism consistent with these results has been developed. First order dependence of the rate on CuSALAD.B₂ was observed in the presence of excess CuSALAD.B₂ over hydrogen peroxide, whereas second order dependence was observed with the latter in excess. The CuBOOCu intermediate was unstable in the presence of EDTA, and a first order dependence of rate of formation of intermediate on both CuSALAD.B₂, and hydrogen peroxide was observed.</p>

Name thesis:degree_name

MS (Master of Science)

Level thesis:degree_level

Thesis - unrestricted

Discipline thesis:degree_discipline

Chemistry

Year dc:date.issued

2004

Author dc:creator

• Beng, Timothy Kum

• Binuclear
• Mononuclear
• Catalase
• Copper(II) complexes
• Hydrogen peroxide
• Copper-base adduct (CuB2)
• Chemistry
• Physical Sciences and Mathematics

Statement dc:rights

• Copyright by the authors.

Repository record dc:identifier

https://dc.etsu.edu/etd/968

OAI identifier oai:identifier

oai:dc.etsu.edu:etd-2125