Table 2.

Second-order rate constants (k₂) observed in reactions of Fe^IV=O complexes with substrates.

Complex a	k2 [M−1 s−1] in CH3CN solution at −30°C b
	CHD	DHA	PPh3
7	18	57	c
2 d	1.2	0.090	1.1
8 d	1.3	2.0	1.5
9 d	0.018	0.016	0.22
10 e	94	310	c

^a[Fe^IV(O)(N4Py)]²⁺ (8, N4Py = bis(2-pyridylmethyl)-bis(2-pyridyl)-methylamine), [Fe^IV(O)(TMC)(CH₃CN)]²⁺ (9, TMC = 1,4,8,11-tetramethylcyclam), [Fe^IV(O)(Me₃NTB)]²⁺ (10, Me₃NTB = tris((N-methyl-benzimidazol-2-yl)methyl)amine)).

^bReaction kinetics for 2, 8 and 9 were measured using 1.0 mM complex. For 7 the larger rates of reaction required the use of 0.1–0.2 mM complex and similarly reduced concentrations of substrate.

^cThis reaction was too fast for measurement of k_obs.

^dKinetic data from reference 5a.

^eKinetic data at −40 °C taken from reference 17.