Intramolecular π-Dimerization in a Diradical

Significance The ferrocene-tethered verdazyl diradical 1 is found to form an intramolecular π-dimer in the solid state as seen in an X-ray crystal structure. The two verdazyl rings of 1 are nearly eclipsed over and drawn-in toward one another, consistent with the formation of an intramolecular π-dimer. Compound 1 is the first reported π-dimer of a verdazyl radical.