Zero-field splitting of quintet conjugated dinitrenes: 2,6-biphenylenedinitrene

2,6-Diazidobiphenylene was synthesized and photolyzed in frozen matrix. The resulting electron spin resonance spectrum showed the formation of 2,6-biphenylenedinitrene as a quintet species with zero field splitting (zfs) parameters ∣D/hc∣=0.260±0.002 cm⁻¹, ∣E/hc∣≤0.0005 cm⁻¹. The zfs parameters are in excellent accord with dipolar models for a quintet state produced by interaction between triplet state nitrene sites.