Molecular photoswitches are molecular machines that are capable of switching between two isomeric forms using light radiation. Organic light switches are of fundamental and practical importance as components of data storage devices and dye-sensitized solar cells. Recent research has also demonstrated their high potential in molecular biology and photopharmacology. Among the studied classes of organic photoswitches, azobenzenes occupy a privileged position due to the ease of their synthesis and good photophysical properties. However, structurally related heterocyclic analogs of azobenzenes have been studied much less.
Researchers of laboratory № 19 of ZIOC in the context of their ongoing research on the synthesis and properties of various nitrogen- and oxygen-containing heterocycles, for the first time obtained light-switchable azocompounds based on 1,2,5-oxadiazole. The developed approach made it possible to synthesize various arylazofurazans and arylazofuroxans with different aryl fragments and different functional groups in the 1,2,5-oxadiazole ring. Upon irradiation with visible light, (E)-arylazo-1,2,5-oxadiazoles were found to undergo photoisomerization to the corresponding (Z)-isomers, which are stable under ambient conditions, while the reverse isomerization of (Z) to (E) is fully achieved only at 60 ° C. It should be especially noted that (Z)-arylazofuroxans release significantly more NO than the corresponding (E)-isomers, which confirms a high potential of these molecular photoswitches in photopharmacology.
The results of the studies were put on the cover of the highly rated journal ChemPhotoChem.
Egor S. Zhilin, Michael S. Polkovnichenko, Ivan V. Ananyev, Leonid L. Fershtat, and Nina N. Makhova Novel Arylazo-1,2,5-oxadiazole Photoswitches: Synthesis, Photoisomerization and Nitric Oxide Releasing Properties ChemPhotoChem 2020, 4, 5346–5354. DOI: 10.1002/cptc.202000157.