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Optical Absorption and Magnetic Field Effect Based Imaging of Transient Radicals
Author(s) -
Beardmore Joshua P.,
Antill Lewis M.,
Woodward Jonathan R.
Publication year - 2015
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201502591
Subject(s) - chemistry , radical , flavin group , photochemistry , magnetoreception , flash photolysis , semiquinone , magnetic field , nuclear magnetic resonance , redox , earth's magnetic field , physics , inorganic chemistry , biochemistry , organic chemistry , quantum mechanics , reaction rate constant , kinetics , enzyme
Short‐lived radicals generated in the photoexcitation of flavin adenine dinucleotide (FAD) in aqueous solution at low pH are detected with high sensitivity and spatial resolution using a newly developed transient optical absorption detection (TOAD) imaging microscope. Radicals can be studied under both flash photolysis and continuous irradiation conditions, providing a means of directly probing potential biological magnetoreception within sub‐cellular structures. Direct spatial imaging of magnetic field effects (MFEs) by magnetic intensity modulation (MIM) imaging is demonstrated along with transfer and inversion of the magnetic field sensitivity of the flavin semiquinone radical concentration to that of the ground state of the flavin under strongly pumped reaction cycling conditions. A low field effect (LFE) on the flavin semiquinone–adenine radical pair is resolved for the first time, with important implications for biological magnetoreception through the radical pair mechanism.