ELECTRON-TRANSFER .42. QUINOXALINIUM RADICALS

被引：9

作者：

CHANG, CR ^{[1
]}

PATON, SJ ^{[1
]}

GELERINTER, E ^{[1
]}

GOULD, ES ^{[1
]}

机构：

[1] KENT STATE UNIV,DEPT CHEM,KENT,OH 44242

来源：

INORGANIC CHEMISTRY | 1979年 / 18卷 / 05期

关键词：

D O I：

10.1021/ic50195a024

中图分类号：

O61 [无机化学];

学科分类号：

070301 ; 081704 ;

摘要：

Reduction of quinoxaline with V2+, Eu2+, or Ti3+ in 1.2 M HClO4 yields a strongly absorbing yellow species (λmax 357 nm, Є 1X104), which also exhibits a 15-line ESR spectrum consistent with formulation as the quinoxalinium radical, QH·. Under favorable conditions, this radical persists for over 1 h in aqueous solution. Observed specific rates for the formation of this radical indicate that it is generated by V2+ principally via an outer-sphere path but by Eu2+ and Ti3+ via inner-sphere reductions. Oxidation of the radical by (NH3)5CoBr2+ proceeds at a rate independent of added quinoxaline, Eu3+, V3+, or Ti(IV), showing that the active species in these reactions is the radical itself, rather than a small quantity of the reducing metal ion in mobile equilibrium with it. The formation of quinoxaline itself, rather than a bromo product, points to an outer-sphere path for this oxidation. It is further found that the quinoxalinium radical does not conform to the linear free-energy relationship which has been found to link the standard potentials of pyridine-related radicals to their outer-sphere reactivities. © 1979, American Chemical Society. All rights reserved.

引用

页码：1294 / 1297

页数：4

共 30 条

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[2]

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