Photoresponsive Nanoparticles utilizing N,N’-Diacylindigo as Photoswitch

The natural dye indigo can be transformed into a soluble photoswitch by double acylation.^[1] The reversible trans–cis isomerization at the central C=C double bond of such N,N’-diacylindigoids can be induced by visible light. Here, the synthesis of the first unsymmetric functionalized derivate with a desired anchor group is shown. By covalent immobilization onto surfaces of magnetic Fe₃O₄ nanoparticles, new photochromic nanomaterial was produced. It has been successfully demonstrated that reversible self-assembly of the photoresponsive nanoparticles can be induced solely by visible light.

[1] Y. Omote, S. Imada, R. Matuzaki, K. Fujiki, T. Nishio, C. Kashima, Bull. Chem. Soc. Jpn. 1979, 52, 3397–3399.