- 作者： 林敬堯 ; 林瑞 ; 許東明 等
- 作者服務機構： 台灣大學化學系
- 中文摘要： The electrochemistry and spectroelectrochemistry of manganese tetrakis (N-methyl-4-pyridyl) porphine (Mn-TMPyP) in aqueous media have been studied. For Mn/sup III/TMPyP two water molecules ligate to the metal center and the formation constant (.beta. /sub 2/) is 0.11 in acetonitrile solution. The pKa/sub 1/ and pKa/sub 2/ for Mn/sup III/TMPyP(H/sub 2/O)/sub 2/ are 10.9 and 12.3, respectively in aqueous media. There is only one pKa at 11.7 for Mn/sup II/TMPyP(H/sub 2/O)/sub 2/. The pKa of the oxo- manganese(IV) porphyrin, O=Mn/sup IV/TMPyP(H/sub 2/O), is 11.3.Mn/sup II/TMPyP demetallates rapidly to free base in acidic aqueous solution. Mn/sup II/TMPyP also undergoes electrocatalysis for oxygen reduction. In acidic conditions, demetallation and catalysis rates are competitive. The transmetallation of MnTMPyP by Zn/sup 2+/ can be achieved in the presence of thiols. The UV-Visible spectra in the reaction process suggest that the formation of some reactive intermediate is essential for the transmetallation.
- 英文摘要： --
- 中文關鍵字： Manganese Porphyrin; Electrochemistry; Transmetallation; Electronic Spectra; Catalysis
- 英文關鍵字： ???錳；電化學；電子光譜；催化
