| Autor: |
Lessa, Josane A., Horn Jr., Adolfo, Bull, Erika S., Rocha, Michelle R., Benassi, Mario, Catharino, Rodrigo R., Eberlin, Marcos N., Casellato, Annelise, Noble, Christopher J., Hanson, Graeme R., Schenk, Gerhard, Silva, Giselle C., Antunes, O. A. C., Fernandes, Christiane |
| Jazyk: |
angličtina |
| Rok vydání: |
2009 |
| Předmět: |
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| Popis: |
Herein, we report reactivity studies of the mononuclear water-soluble complex [Mn(II)(HPClNOL)(η1-NO3)(η2-NO3)] 1, where HPClNOL ) 1-(bis-pyridin-2-ylmethyl-amino)-3-chloropropan-2-ol, toward peroxides (H2O2 and tertbutylhydroperoxide). Both the catalase (in aqueous solution) and peroxidase (in CH3CN) activities of 1 were evaluated using a range of techniques including electronic absorption spectroscopy, volumetry (kinetic studies), pH monitoring during H2O2 disproportionation, electron paramagnetic resonance (EPR), electrospray ionization mass spectrometry in the positive ion mode [ESI(+)-MS], and gas chromatography (GC). Electrochemical studies showed that 1 can be oxidized to Mn(III) and Mn(IV). The catalase-like activity of 1 was evaluated with and without pH control. The results show that the pH decreases when the reaction is performed in unbuffered media. Furthermore, the activity of 1 is greater in buffered than in unbuffered media, demonstrating that pH influences the activity of 1 toward H2O2. For the reaction of 1 with H2O2, EPR and ESI(+)-MS have led to the identification of the intermediate [Mn(III)Mn(IV)(μ- O)2(PClNOL)2]+. The peroxidase activity of 1 was also evaluated by monitoring cyclohexane oxidation, using H2O2 or tert-butylhydroperoxide as the terminal oxidants. Low yields ( |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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