Trans-FAAzo-4
4-Butyl-Azo-4:0-Acid-1
In its dark-adapted state, trans-FAAzo-4 exists predominantly in the trans-configuration. UV-vis spectroscopy has shown that trans- to cis- isomerization occurs via light irradiation at 8 = 365 nm. This process is reversible and can be achieved via light irradiation at 8 = 460 nm. Trans-AzCA4 is thus classified as a regular azobenzene requiring ultraviolet light for isomerization.
Frank, J., Moroni, M., Moshourab, R. et al. Photoswitchable fatty acids enable optical control of TRPV1. Nat Commun 6, 7118 (2015). https://doi.org/10.1038/ncomms8118