Issue 5, 2015

Probing a chemical compass: novel variants of low-frequency reaction yield detected magnetic resonance

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.

Graphical abstract: Probing a chemical compass: novel variants of low-frequency reaction yield detected magnetic resonance

Supplementary files

Article information

Article type
Paper
Submitted
11 Sep 2014
Accepted
08 Dez 2014
First published
24 Dez 2014

Phys. Chem. Chem. Phys., 2015,17, 3550-3559

Author version available

Probing a chemical compass: novel variants of low-frequency reaction yield detected magnetic resonance

K. Maeda, J. G. Storey, P. A. Liddell, D. Gust, P. J. Hore, C. J. Wedge and C. R. Timmel, Phys. Chem. Chem. Phys., 2015, 17, 3550 DOI: 10.1039/C4CP04095C

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements