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.