Activation of Non-Heme Iron-Nitrosyl Complexes: Turning Up the Heat

The chemistry of nonheme iron centers with NO in different oxidation states has experienced a renaissance in the last 10 years because of recent findings of their involvement in N2O generation (in nitric oxide reductases - NORs), dinitrosyl iron complex (DNIC) formation, NO sensing in transcription factors, and the biosynthesis of natural products that contain N-nitroso groups. Using model complexes, great strides have been made in our understanding of the reactivity and electronic structures of nonheme iron-nitrosyl complexes in different oxidation states, and yet there is much more to be learned. Whereas many nonheme, high-spin (hs) {FeNO}(7) complexes, formed from the reaction of NO with Fe(II), have been prepared and thoroughly characterized (although even in this case, their ability to directly couple two NO to N2O in dinuclear systems had been overlooked for a long time), much less is known about nonheme iron-nitrosyl complexes in other oxidation states, especially hs-{FeNO}(6) and hs-{FeNO}(8). In both of these cases, very few examples have been reported, and the reactivity of these complexes is largely unexplored. This is an exciting area of coordination chemistry that warrants more attention in the field.