Electrochemical and optical study of carotenoids in TX 100 micelles: Electron transfer and a large blue shift
The first oxidation waves of 8{prime}-apo-{beta}-caroten-8{prime}-al (I) and 8{prime}-apo-{beta}-caroten-8{prime}nitrile (II) in TX100 micelles are clearly observed in their cyclic voltammograms (CVs). The CV of {beta}-carotene (III) in TX100 micelles shows that III is not oxidized. It is proposed that the hydrophobic barrier of the micelle is an important reason for the failure to oxidize III, which is totally located in the hydrophobic center of the micelle. The oxidation of I and II demonstrates that electrons can be transferred through the terminal groups over a distance of ca. 22 {angstrom}. An unusually large blue band shift (100 nm, relative to that in CH{sub 2}Cl{sub 2}) is observed in the optical absorption spectrum of 7{prime}-apo-7{prime},7{prime}-dicyano-{beta}-carotene (IV) in TX100 micelles. This phenomenon is not observed in the absorption spectra of other studied carotenoids. A change in the ground-state electronic structure of IV, due to the influence of water near the terminal dicyanomethylidene group, is proposed to be the major reason for this large band shift.
- Research Organization:
- Univ. of Alabama, Tuscaloosa, AL (US)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- FG02-86ER13465
- OSTI ID:
- 20001122
- Journal Information:
- Journal of Physical Chemistry B: Materials, Surfaces, Interfaces, amp Biophysical, Vol. 103, Issue 42; Other Information: PBD: 21 Oct 1999; ISSN 1089-5647
- Country of Publication:
- United States
- Language:
- English
Similar Records
Role of excited singlet state in the photooxidation of carotenoids: A time-resolved Q-band EPR study
Simultaneous electrochemical and electron paramagnetic resonance studies of carotenoid cation radicals and dications