Ia. Salem et Ah. Gemeay, KINETICS AND MECHANISM OF THE OXIDATION OF L-ASCORBIC-ACID BY THE ,N'-ETHYLENEBIS(SALICYLIDENEIMINATO)MANGANESE(III) COMPLEX IN AQUEOUS-SOLUTION, Transition metal chemistry, 21(2), 1996, pp. 130-134
The kinetics of oxidation of L-ascorbic acid by the N,N'-ethylenebis(s
alicylideneiminato) manganese(III) complex have been studied over the
4.5-9.3 pH range. An intermediate ascorbate complex was formed which h
ad an inhibiting effect on the rate of the redox reaction. The rapid f
ormation of this intermediate was followed using the stopped-flow tech
nique, whereas its slow decomposition was monitored using a convention
al spectrophotometer. The formation of this intermediate was strongly
pH dependent. Addition of sodium perchlorate and sodium dodecyl sulpha
te (anionic surfactant) affected the reaction rate. A probable mechani
sm comprising both the intermediate formation and the overall redox re
action is discussed.