A bridging hexazene (RNNNNNNR) ligand from reductive coupling of azides.

This communication reports the first examples of transition metal complexes containing an RNNNNNNR 2- ligand. Addition of 1-azidoadamantane to the diiron(I) synthon LRFeNNFeL R (L R = HC[C(R)N(2,6- iPr 2C 6H 3)] 2; R = methyl, tert-butyl) leads to the diiron complexes L RFe(mu-eta2:eta2-AdN6Ad)FeLR, which are surprisingly thermally stable. Magnetic, Mössbauer, and crystallographic data are consistent with pairs of high-spin iron(II) ions antiferromagnetically coupled through a dianionic AdN6Ad 2- bridge.