Simultaneous electrochemical and electron paramagnetic resonance studies of carotenoids. Effect of electron donating and accepting substituents

Journal Article · Thu Aug 11 00:00:00 EDT 1994 · Journal of Physical Chemistry; (United States)

DOI:https://doi.org/10.1021/j100083a006· OSTI ID:7191436

Jeevarajan, A S; Khaled, M; Kispert, L D ^[1]

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1. Univ. of Alabama, Tuscaloosa, AL (United States)

A series of substituted phenyl-7[prime]-apocarotenoids with varying electron donating and accepting substituents was examined by cyclic voltammogram (CV) and simultaneous electrochemical electron paramagnetic resonance (SEEPR). Carotenoids substituted with electron donating groups are more easily oxidized than those with electron accepting substituents. Comproportionation constants for the dication and the neutral species were measured by SEEPR techniques and by simulation of the CVs. The [Delta]H[sub pp] of the SEEPR spectrum of the cation radicals varies from 13.2 to 15.6 G, and the g factors are 2.0027 [+-] 0.0002. These EPR parameters suggest a polyene [pi]-cation radical structure. The CVs are calculated using DigiSim, a CV simulation program, and the proposed mechanism involves three electrode reactions and two homogeneous reactions. 24 refs., 3 figs., 2 tabs.

• DOE Contract Number: FG05-86ER13465
• OSTI ID: 7191436
• Journal Information: Journal of Physical Chemistry; (United States), Vol. 98:32; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE
CAROTENOIDS
ELECTRON SPIN RESONANCE
NUCLEAR MAGNETIC RESONANCE
OXIDATION
THIN-LAYER CHROMATOGRAPHY
VOLTAMETRY
COMPILED DATA
COMPUTERIZED SIMULATION
ELECTROCHEMISTRY
PHOTOSYNTHESIS
RADICALS
CHEMICAL REACTIONS
CHEMISTRY
CHROMATOGRAPHY
DATA
HYDROCARBONS
INFORMATION
MAGNETIC RESONANCE
NUMERICAL DATA
ORGANIC COMPOUNDS
PHOTOCHEMICAL REACTIONS
PIGMENTS
RESONANCE
SEPARATION PROCESSES
SIMULATION
SYNTHESIS
TERPENES
140505* - Solar Energy Conversion- Photochemical
Photobiological
& Thermochemical Conversion- (1980-)
400102 - Chemical & Spectral Procedures
990200 - Mathematics & Computers