A combined optical and EPR spectroscopy study: azobenzene-based biradicals as reversible molecular photoswitches

摘要: Azobenzene compounds are known as versatile examples for photoswitchable systems because of their isomeric cis- and trans-configurations. The switching between these isomers can be reversibly controlled by light excitation. In this study we characterize two members class joining the azobenzene moiety with each paramagnetic nitroxide spin labels. Two different linkers were chosen to tune molecular properties. combined approach using optical EPR spectroscopy proved reversibility photoexcitation high fatigue resistance. Furthermore, depending on nature linker, PELDOR distance measurements monitored clearly photo-induced structural changes unit. Thus, a powerful concept is presented resulting from combination complementary spectroscopic techniques.