An Anthracenyl-Substituted Nitronyl Nitroxide

An anthracene derivative containing a nitronyl nitroxide group on the side aromatic ring, i.e., 1-bromo-4,5-di-n-butoxy-8-(4,4,5,5-tetramethyl-3-oxide-1-oxyl-4,5-dihydro-1H-imidazole-2-yl)anthracene, was described. The radical-substituted anthracene was prepared by the cross-coupling reaction of 1,8-dibromo-4,5-dibutoxyanthracene with an organogold derivative of nitronyl nitroxide. Note, the second bromo atom did not enter the reaction. Molecular and crystal structure of the synthesized nitronyl nitroxide was proven by XRD. The angle between the planes of the anthracene core and adjacent paramagnetic moiety is 51.2°, and the intramolecular distance between the nitroxide O atoms and anthracene H atom at the peri-position is 2.52 Å, which is less than the sum of van der Waals radii of the C and O atoms. This structural feature as well as the reactivity of 1,8-dibromo-anthracenes is important for the design of zigzag graphene nanoribbons terminated with different group radicals.