- 作者: 林律銘,黃敬淳,黃代莉,葉玉棠
- 作者服務機構: Department of Chemistry, Tunghai Christian University, Taichung, Taiwan, R.O.C.
- 中文摘要: The reductions of Co(terpy)23+ and Co(edta)- complexes by ascorbic acid have been subjected to a detailed kinetic study in the range of pH = 1-10.9. For each complex the rate law of the reaction is interpreted as a rate determining reaction between Co(III) complex and the ascorbic acid in the form of HA- (k1) and A2- (k2), depending on the pH of the solution, followed by a rapid scavenge of the ascorbic acid radicals by Co(III) complex. With given Ka1 and Ka2, the rate constants are k1 = 0.25 and 9.87 ’ 10-5 M-1s-1, k2 = 1.28 ’ 106 and 18.7 M-1s-1 for Co(terpy)23+ and Co(edta)- complexes, respectively, at T = 25 °C and m = 0.50 M (terpy) and 1.0 M (edta) HClO4/LiClO4. The mechanism of the reaction is discussed on the basis of Marcus theory for outer sphere electron transfer process. Spin change and charge effect, duly considered, account for the non-adiabatic behavior in the reduction of Co(edta)- complex.
- 英文摘要: --
- 中文關鍵字: Co(III) complex; Ascorbic acid; Outer-sphere electron transfer; Marcus theory.
- 英文關鍵字: --