Reactivity oftert-butylperoxyl radical with manganese(III), cobalt(II), and nickel(II) salicylidene Schiff base chelates

Autor: Hakob G. Tonikyan, Makich V. Musaelyan, Seyran H. Minasyan, John R. J. Sorenson, L. A. Tavadyan, Aram E. Barsegyan
Rok vydání: 2007
Předmět:
Zdroj: International Journal of Chemical Kinetics. 39:431-439
ISSN: 1097-4601
0538-8066
DOI: 10.1002/kin.20250
Popis: Salicylidene Schiff base chelates (R,R)-(–)-N,N′-bis(3,5-di-tert-butylsalicylidene)-1,2-cyclohexanediaminomanganese(III) chloride, (R,R)-(–)-N,N′-bis(3,5-di-tert-butylsalicylidene)-1,2-cyclohexanediaminocobalt(II), N,N′-bis(salicylidene)-ethylenediaminocobalt(II), N,N′-bis(salicylidene)ethylenediaminonickel(II), and N,N′-bis(salicylidene)ethylenediaminoaquacobalt(II), as well as (R,R)-(–)-N,N′-bis(3,5-di-tert-butylsalicylidene)1,2-cyclohexanediamine, were kinetically examined as antioxidants in the scavenging of tert-butylperoxyl radical (tert-butylOO•). Absolute rate constants and corresponding Arrhenius parameters were determined for reactions of tert-butylOO• with these chelates in the temperature range −52.5 to −11°C. High reactivity of tert-butylOO• with Mn(III) and Co(II) salicylidene Schiff base chelates was established using a kinetic electron paramagnetic resonance method. These salicylidene Schiff base chelates react in a 1:1 stoichiometric fashion with tert-butylOO• without free radical formation. Ultraviolet–visible spectrophotometry and differential pulse voltammetry established that the rapid removal rate of tert-butylOO• by these chelates is the result of Mn(III) oxidation to Mn(IV) and Co(II) oxidation to Co(III) by tert-butylOO•. It is concluded that removal of alkylperoxyl radical by Mn(III) and Co(II) salicylidene Schiff base chelates may partially account for their biological activities. © 2007 Wiley Periodicals, Inc. Int J Chem Kinet 39: 431–439, 2007
Databáze: OpenAIRE
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