In contrast to diradicals connected by alternant hydrocarbons, only a few studies on those connected by nonalternant hydrocarbons have been reported. The syntheses, structures, and magnetic properties of azulene-1,3-diyl linked bis(nitronyl nitroxide) (NN Az) and bis(iminonitroxide) (IN Az) diradicals and their Cu(hfac) (hfac=hexafluoroacetylacetonate) complexes were investigated. NN Az was shown to have an intramolecular ferromagnetic interaction with J /k =+10.0 K (H=-2JS ⋅S ) between (nitronyl nitroxide) spins, whereas IN Az was estimated to have a much weaker intramolecular magnetic interaction. The reactions of NN Az and IN Az with Cu(hfac) gave a 1:2 [{Cu(hfac) } (NN Az)] complex and a 1:1 [Cu(hfac) (IN Az)]⋅C H complex, respectively. [{Cu(hfac) } (NN Az)] showed strong intramolecular antiferromagnetic interactions (J /k ≈-800 K, J /k ≈-500 K) between the Cu spins and the coordinating NN spins, whereas [Cu(hfac) (IN Az)] exhibited a ferromagnetic exchange interaction (J /k =+114 K) between the Cu spin and the imino-coordinated iminonitroxide spin.

Condensed phenoxazine dimer was synthesized and characterized. X-ray crystallographic analysis of the dimer shows a double-butterfly structure, in which the nitrogen atoms are located above and below the molecular plane. Radical cation salt of the dimer was obtained using tris(4-bromophenyl)aminium hexafluoroantimonate as the oxidant. The salt is air-stable in solid and solution states. The cation structure was evaluated by X-ray crystallographic analysis, showing that the phenoxazine units were converted to a planar structure upon oxidation.