Derivatives of (nitro)cobalt picket fence porphyrin with oxygen-donating ligands have been prepared in solution and in the solid state. Crystal structures of two of these derivatives, (H2O)CoTpivPP(NO2) and (CH3OH)CoTpivPP(NO2), have been determined. The ethanol complex (C2H5OH)Co(TPP)(NO2) has been obtained and spectrally characterized using sublimed layers methodology. The formation constant and the DeltaH degrees value of the association reaction with ethanol have been determined by FTIR measurements in CCl4 solution. Catalytic oxygen activation and oxo-transfer reactions of these derivatives have been assessed in solution. Correlations between the oxo-transfer reactivity, thermodynamics, and characteristics of the nitro ligand show that although calculated and observed ONO vibrational spectra and bond lengths suggest activation of the NO2 ligand and enhanced oxo-transfer reactions as seen in the analogous five-coordinate complexes, density functional theory calculations support that thermodynamics limits oxo-atom transfer reactions in these six-coordinate systems.

High‐valent iron‐nitrido species are nitrogen analogues of iron‐oxo species which are versatile reagents for C−H oxidation. Nonetheless, C−H activation by iron‐nitrido species has been scarcely explored, as this is often hampered by their instability and short lifetime in solutions. Herein, the hydrogen atom transfer (HAT) reactivity of an Fe porphyrin nitrido species (2 c) toward C−H substrates was studied in solutions at room temperature, which was achieved by nanosecond laser flash photolysis (LFP) of its FeIII‐azido precursor (1 c) supported by a bulky bis‐pocket porphyrin ligand. C−H bonds with bond dissociation enthalpies (BDEs) of up to ≈84 kcal mol−1 could be activated, and the second‐order rate constants (k2) are on the order of 102–104 s−1 m−1. The Fe‐amido product formed after HAT could further release ammonia upon protonation.