Starazo triple switches – synthesis of unsymmetrical 1,3,5-tris(arylazo)benzenes

• Andreas H. Heindl and
• Hermann A. Wegner

Beilstein J. Org. Chem. 2020, 16, 22–31, doi:10.3762/bjoc.16.4

• characterized in terms of their isomerization behavior using UV–vis and 1H NMR spectroscopy. The efficient synthesis of this new class of unsymmetrical tris(arylazo)benzenes opened new avenues to novel multistate switching materials. Keywords: multistate photoswitches; synthesis; tris(arylazo)benzene

• access, this highly interesting class of multistate photoswitches would be accessible for detailed spectroscopic investigations, leading to fundamental insights applicable to the design of intelligent photoresponsive materials. Results and Discussion Initially, two different synthetic strategies were

• switchable multistate photoswitches: previous [11][12] and present work. a) UV–vis spectra of tris(arylazo)benzenes 3a/3b in ethanol. b) Reversible photoisomerization of 3a and c) 3b using light of 365 nm wavelength to induce E→Z isomerization and of 448 nm wavelength for photochemical back-conversion