Probing a chemical compass

novel variants of low-frequency reaction yield detected magnetic resonance

Kiminori Maeda, Jonathan G. Storey, Paul A. Liddell, Devens Gust, P. J. Hore, C. J. Wedge, Christiane R. Timmel

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

We present a study of a carotenoid-porphyrin-fullerene triad previously shown to function as a chemical compass: the photogenerated carotenoid-fullerene radical pair recombines at a rate sensitive to the orientation of an applied magnetic field. To characterize the system we develop a time-resolved Low-Frequency Reaction Yield Detected Magnetic Resonance (tr-LF-RYDMR) technique; the effect of varying the relative orientation of applied static and 36 MHz oscillating magnetic fields is shown to be strongly dependent on the strength of the oscillating magnetic field. RYDMR is a diagnostic test for involvement of the radical pair mechanism in the magnetic field sensitivity of reaction rates or yields, and has previously been applied in animal behavioural experiments to verify the involvement of radical-pair-based intermediates in the magnetic compass sense of migratory birds. The spectroscopic selection rules governing RYDMR are well understood at microwave frequencies for which the so-called 'high-field approximation' is valid, but at lower frequencies different models are required. For example, the breakdown of the rotating frame approximation has recently been investigated, but less attention has so far been given to orientation effects. Here we gain physical insights into the interplay of the different magnetic interactions affecting low-frequency RYDMR experiments performed in the challenging regime in which static and oscillating applied magnetic fields as well as internal electron-nuclear hyperfine interactions are of comparable magnitude. Our observations aid the interpretation of existing RYDMR-based animal behavioural studies and will inform future applications of the technique to verify and characterize further the biological receptors involved in avian magnetoreception.

Original languageEnglish
Pages (from-to)3550-3559
Number of pages10
JournalPhysical Chemistry Chemical Physics
Volume17
Issue number5
Early online date24 Dec 2014
DOIs
Publication statusPublished - 7 Feb 2015
Externally publishedYes

Fingerprint

Magnetic resonance
Magnetic Fields
magnetic resonance
Magnetic Resonance Spectroscopy
Magnetic fields
low frequencies
Fullerenes
carotenoids
magnetic fields
Carotenoids
fullerenes
animals
magnetic compasses
Animals
birds
Microwave frequencies
Porphyrins
Birds
Microwaves
microwave frequencies

Cite this

Maeda, Kiminori ; Storey, Jonathan G. ; Liddell, Paul A. ; Gust, Devens ; Hore, P. J. ; Wedge, C. J. ; Timmel, Christiane R. / Probing a chemical compass : novel variants of low-frequency reaction yield detected magnetic resonance. In: Physical Chemistry Chemical Physics. 2015 ; Vol. 17, No. 5. pp. 3550-3559.
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Probing a chemical compass : novel variants of low-frequency reaction yield detected magnetic resonance. / Maeda, Kiminori; Storey, Jonathan G.; Liddell, Paul A.; Gust, Devens; Hore, P. J.; Wedge, C. J.; Timmel, Christiane R.

In: Physical Chemistry Chemical Physics, Vol. 17, No. 5, 07.02.2015, p. 3550-3559.

Research output: Contribution to journalArticle

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