ISSN:
1588-2837
Keywords:
Dioxygen activation
;
catechol oxidation
;
cobaloxime catalysis
;
catecholase model
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract In the presence of triphenylphosphinecobaloxime(II), 3,5-di-tert-butylcatechol undergoes catalytic oxidative dehydrogenation to the corresponding 1,2-benzoquinone (DTBQ) at room temperature and atmospheric dioxygen pressure. The semiquinone anion radical (DBS•−) and its cobaloxime(III), complex CoIII(DBSQ)•−) have been detected as intermediates by ESR spectroscopy. The kinetics were followed in benzene by measuring the dioxygen uptake as a function of time. The reaction is somewhat faster in MeOH, which is due to the greater stability of the hydrogen-bonded intermediate (X) formed from superoxocobaloxime (CoIIIO2) and the catechol. H-atom abstraction occurs in the rate-determining decomposition of X. The system investigated is a functional model of catecholase (oxidase) activity, based on free-radical intermediates, a possibility recently demonstrated for certain oxidoreductases.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02475268
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