Table 2. Gibbs Free Energies of Activation (ΔG^⧧) for the Initial Attack of the Fe^III–OOH Moiety on Nitrobenzene, Calculated for Different Models of the Active Site^a Relative to Reactant Complex.

	ΔG⧧ [kcal mol–1]
	nonconcerted			concerted
	O1–C2 attack	O–C1 attack	O–C2 attack	O1–C2 attack	O–C1 attack	O–C2 attack
model 1		43.9	38.7	25.7	20.6	19.5
model 2		43.4	37.5		22.0
model 3	31.4	39.5	22.8
model 4	29.1	37.5	29.9

^aSee text for description.