The formation, characterization, and reactivity of models for the active intermediates of horseradish peroxidase and cytochrome P-450 monoxygenases /
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| Other Authors: | , , |
| Format: | Thesis Book |
| Language: | English |
| Published: |
1988.
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| Online Access: | Link to ProQuest copy Link to OAKTrust copy ProQuest, Abstract |
| Abstract: | Combination of meso-[tetrakis(2,6-dichlorophenyl)porphinato]iron perchlorate with pentafluoroiodosobenzene, m-chloroperbenzoic acid, or ozone in acetonitrile at -35°C yields a green porphyrin-oxene adduct. This species, which has been characterized by spectroscopic, magnetic and electrochemical methods, cleanly and stereospecifically epoxidizes olefins (>99% exo-norbornene oxide). The reaction chemistry and electronic characterization of the adduct are consistent with an oxygen atom covalently bound to an iron-porphyrin radical center [(P+)Fe(O)]+. The latter has the spectral, magnetic, and redox characteristics of compound I of horseradish peroxidase (HRP), and the selective stereospecific oxygenase character of the reactive intermediate for cytochromes P-450. Reduction of the green species by one-electron equivalent yields a red species, PFe(O), which has the spectral characteristics and reactivity of compound n of HRP. The iron porphyrin complex is an efficient catalyst for (a) the stereospecific epoxidation of olefins and (b) the oxidative cleavage of α-diols by F5PhIO and m-ClPhC(O)OOH; with H2O2 there is extensive attack on the porphyrin ring and no significant reaction with olefins or α-diols. Addition of PhCH2S- to the iron-porphyrin complex in cold (-35°C) acetonitrile or N,N-dimethylformamide yields (Cl8TPP)Fe-SCH2Ph (7), which reacts with ozone or m-chloroperbenzoic acid to give an oxene adduct. The reaction chemistry and electronic characterization of the adduct are consistent with an oxygen atom covalently bound to an iron-porphyrin center (Cl8TPP)(PhCH2S)Fe(O) (8). The spectral, magnetic, and redox properties of 7 and 8 have been characterized in relation to the reaction cycle of cytochromes P-450. |
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| Item Description: | "Major subject: Chemistry." Typescript (photocopy). Vita. |
| Physical Description: | xvi, 155 leaves : illustrations ; 29 cm |
| Bibliography: | Includes bibliographical references. |