SIMULTANEOUS ELECTROCHEMICAL AND ELECTRON-PARAMAGNETIC-RESONANCE STUDIES OF KETO AND HYDROXY CAROTENOIDS

被引：37

作者：

JEEVARAJAN, AS ^{[1
]}

KHALED, M ^{[1
]}

KISPERT, LD ^{[1
]}

机构：

[1] UNIV ALABAMA,DEPT CHEM,TUSCALOOSA,AL 35487

来源：

CHEMICAL PHYSICS LETTERS | 1994年 / 225卷 / 4-6期

关键词：

D O I：

10.1016/0009-2614(94)87091-8

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

Cyclic voltammogram (CV) and simultaneous electrochemical and electron paramagnetic resonance (SEEPR) measurements have been carried out on the oxygenated carotenoids: echinenone, canthaxanthin, isozeaxanthin and rhodoxanthin in dichloromethane. The CV displays are markedly different from that of beta-carotene. Comproportionation constants, deduced from EPR spin concentration measurements of electrochemically oxidized dihydroxy beta-carotene and several keto carotenoids vary by four orders of magnitude. DELTAH(pp) values deduced from the SEEPR spectra of the cation radicals are in the range 13.2 to 14.5 G and the g-factors are 2.0027 +/- 0.0002. These EPR parameters are in accordance with a polyene pi-cation radical structure. Theoretical CVs are calculated using DigiSim, a CV simulation program, and the proposed mechanism involves three electrode and two homogeneous reactions.

引用

页码：340 / 345

页数：6

共 21 条

[1] CAROTENOIDS OF RHIZOBIA .4. ISOLATION AND STRUCTURE ELUCIDATION OF THE CAROTENOIDS OF A MUTANT OF RHIZOBIUM-LUPINI [J].