A New Photoisomerization of 1,2,4-Oxadiazoles. A Computational Study

The photochemical isomerization of 1,2,4-oxadiazole derivatives to 1,2,4-triazoles has been studied at B3LYP/6-311G+(d,p) level of theory. The reaction occurred in the presence of Ru(bpy)2Cl2. The irradiation of the Ru complex allowed the substitution of chlorine with the substrate. The irradiation at 760 nm of this new complex led to an electron transfer process that favors the transfer of a hydrogen atom from the hydrazonic NH group to the N atom at the fourth position in the 1,2,4-oxadiazole ring. The resulting radical cation cyclized to give a reaction product through Dewar isomer structure.