Structural and Environmental Studies of the Vitamin E (α-Tocopheroxyl) Radical Using Time-Resolved Resonance-Raman Spectroscopy
The time-resolved resonance Raman spectrum of the vitamin E free radical, α-tocopheroxyl, has been measured. The spectrum is similar to that obtained for 4-methoxyphenoxyl, i.e. consisting of two intense bands at ca. 1500 and 1595 cm−1, assigned to the C=C (v 8a) and C-O (v 7a) stretches respectively. This indicates that the vitamin E free radical is stabilised by electron delocalisation involving the chromanol ring oxygen. The ratio of these two bands increases with increase in solvent polarity. This has been used to determine the position of the α-tocopherol radical within lipid bilayer membranes.
KeywordsProbe Laser Lipid Bilayer Membrane Transient Absorption Spectrum Laser Flash Photolysis Resonance Raman Spectrum
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