A novel azo-thiourea based visible light switchable anion receptor

A novel azo-thiourea based anion receptor can be synthesized by coupling a bis-azoaniline motif with butyl isothiocyanate with 45% yield under mild conditions. It was found that azo-thiourea was an excellent receptor to recognize various di-carboxylate anions. It can serve as a colorimetric sensor for azelate ion and led to a significant change in the absorption spectrum. Furthermore, a reversible trans-cis isomerization of azo-thiourea induced by visible lights was confirmed by 1H NMR spectroscopy.81