Azo compounds -- Absorption, Photochemistry, Nanostructured materials
Introduction of S-ethyl groups in all four ortho positions of azobenzene prevents reduction of the azo group by intracellular glutathione, while enhancing the absorptivity to ∼10000 M−1 cm−1 in the blue and green regions of the visible spectrum. cis-to-trans isomerization occurs thermally on the minutes timescale. Further, this substitution pattern permits switching with red light, a color that is more penetrating through biological tissues than other parts of the visible spectrum.
Samanta, S.; McCormick, T. M.; Schmidt, S. K.; Seferos, D. S.; Woolley, G. A. “Robust visible light photoswitching with ortho-thiol substituted azobenzenes” Chemical Communications. 49 (87), 10314-10316, 2013.