Structural and spectroscopic characterization of an Fe(VI) bis(imido) complex

Nitrogen lifts iron to hexavalence The myriad ways that iron can interact with oxygen have been amply studied in biochemical and geochemical contexts. More recently, chemists have explored the extent to which nitrogen can likewise stabilize iron in high oxidation states. Martinez et al. now report that an iron center coordinated by carbene ligands can react with an organic azide to form a pentavalent bis(imido) complex with two Fe=N bonds. One-electron oxidation then accessed the Fe(VI) oxidation state. Both compounds were sufficiently stable for crystallographic characterization. Science , this issue p. 356