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Speciation 98: Abstracts
Kiricsi, I.1, Böngyik, E.1, Hernadi, K.1, B.Nagy, J.2, and Penke, B.3
1 Applied Chemistry Department, JATE, H-6720 Szeged, Rerrich
B. tér 1., Hungary;
2 Laboratoire de R.M.N., FUNDP, 61 rue de Bruxelles, B-5000
Namur, Belgium;
3 Department of Organic Chemistry, JATE, H-6720 Szeged, Dóm
tér 8. Hungary
During enzyme modelling a copy of the active center of enzymes is built into a matrix in order to mimic the original enzyme activity and selectivity. In this contribution we attempted to simulate the active center of superoxide-dismutaze (containing porphyrin structure) using immobilized imidazole or histidine complex of transition metals.
For sample preparation the following materials were used: cobalt or copper as transition metals, imidazole or histidine as ligands, Bentolit-H or MCM-41 as solid matrices, respectively. Our samples were prepared by two different methods. In the first case, complexes were prepared ex situ, then they were introduced into the pores. In the second case, ion-exchanged microporous materials were used as starting media and complexes were synthesized inside the pores by adding ligand molecules afterwards.
For the physico-chemical characterizations of the samples, thermal analysis, EPR spectroscopy, and X-ray diffraction techniques were applied. From these results we can deduce the formation and the stability of immobilized complexes. Catalytic effect of these samples were tested in the decomposition of different peroxide compounds such as hydrogen peroxide, tert-butyl hydroperoxide, and cumene hydroperoxide. Quantitative analysis was carried out by using UV-VIS spectroscopy for titanyl compound of H2O2 or by gas chromatography for organic peroxides. From these kinetic investigations it can be concluded, that certain immobilized complexes are able to decompose peroxide compounds more rapidly than either aqueous complexes or ion-exchanged microporous samples can do. Activity of these immobilized complexes depends not only on the nature of transition metal, ligand or solid matrix, but on the method of sample preparation, too.
