Radical−Radical Interaction through a Saturated Link: Methylenebis-6-oxoverdazyl

The diradical methylenebis(1,5-diisopropyl-6-oxoverdazyl) was synthesized by benzoquinone oxidation
of the corresponding bis(tetrazane). The diradical crystallizes in the monoclinic space group C2/c with
cell parameters a = 21.1411(8) Å, b = 12.4781(5) Å, c = 8.2457(3) Å, β = 108.638(2)°, V = 2061.15
Å3, Z = 4. Magnetic measurements indicate the diradical has a singlet ground state and triplet excited
state at 150 cm-1. Interaction between the nonconjugated radical centers is also seen in the UV−vis
spectrum as a broad shoulder near 500 nm that is not apparent in the spectrum of the monoradical.