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Scandium ion-enhanced oxidative dimerization and N -demethylation of N, N -dimethylanilines by a non-heme iron(IV)-oxo complex
- Title
- Scandium ion-enhanced oxidative dimerization and N -demethylation of N, N -dimethylanilines by a non-heme iron(IV)-oxo complex
- Authors
- Park J.; Morimoto Y.; Lee Y.-M.; You Y.; Nam W.; Fukuzumi S.
- Ewha Authors
- 남원우; Shunichi Fukuzumi; 이용민
- SCOPUS Author ID
- 남원우; Shunichi Fukuzumi; 이용민
- Issue Date
- 2011
- Journal Title
- Inorganic Chemistry
- ISSN
- 0020-1669
- Citation
- Inorganic Chemistry vol. 50, no. 22, pp. 11612 - 11622
- Indexed
- SCI; SCIE; SCOPUS
- Document Type
- Article
- Abstract
- Oxidative dimerization of N,N-dimethylaniline (DMA) occurs with a nonheme iron(IV)-oxo complex, [FeIV(O)(N4Py)]2+ (N4Py = N,N-bis(2-pyridylmethyl)-N-bis(2-pyridyl)methylamine), to yield the corresponding dimer, tetramethylbenzidine (TMB), in acetonitrile. The rate of the oxidative dimerization of DMA by [FeIV(O)(N4Py)]2+ is markedly enhanced by the presence of scandium triflate, Sc(OTf)3 (OTf = CF3SO3 -), when TMB is further oxidized to the radical cation (TMB•+). In contrast, we have observed the oxidative N-demethylation with para-substituted DMA substrates, since the position of the C-C bond formation to yield the dimer is blocked. The rate of the oxidative N-demethylation of para-substituted DMA by [FeIV(O) (N4Py)]2+ is also markedly enhanced by the presence of Sc(OTf) 3. In the case of para-substituted DMA derivatives with electron-donating substituents, radical cations of DMA derivatives are initially formed by Sc3+ ion-coupled electron transfer from DMA derivatives to [FeIV(O)(N4Py)]2+, giving demethylated products. Binding of Sc3+ to [FeIV(O)(N4Py)]2+ enhances the Sc3+ ion-coupled electron transfer from DMA derivatives to [Fe IV(O)(N4Py)]2+, whereas binding of Sc3+ to DMA derivatives retards the electron-transfer reaction. The complicated kinetics of the Sc3+ ion-coupled electron transfer from DMA derivatives to [FeIV(O)(N4Py)]2+ are analyzed by competition between binding of Sc3+ to DMA derivatives and to [FeIV(O)(N4Py)] 2+. The binding constants of Sc3+ to DMA derivatives increase with the increase of the electron-donating ability of the para-substituent. The rate constants of Sc3+ ion-coupled electron transfer from DMA derivatives to [FeIV(O)(N4Py)]2+, which are estimated from the binding constants of Sc3+ to DMA derivatives, agree well with those predicted from the driving force dependence of the rate constants of Sc3+ ion-coupled electron transfer from one-electron reductants to [FeIV(O)(N4Py)]2+. Thus, oxidative dimerization of DMA and N-demethylation of para-substituted DMA derivatives proceed via Sc3+ ion-coupled electron transfer from DMA derivatives to [FeIV(O)(N4Py)]2+. © 2011 American Chemical Society.
- DOI
- 10.1021/ic201545a
- Appears in Collections:
- 자연과학대학 > 화학·나노과학전공 > Journal papers
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