Table 6. Comparison of Second-Order Rate Constants for HAT Reactions Affected by Complexes 1b–4b and [Fe^IV(O)(N4Py)]^2+a.

alkaneb	DC–Hc(kal/mol)	k2d (M–1 s–1) for 1b	k2d (M–1 s–1) for 2b	k2d (M–1 s–1) for 3b	k2d (M–1 s–1) for 4b	k2d (M–1 s–1) for [FeIV(O)N4Py]2+
triphenylmethane (1)	81	8.2 × 10–2	8.43 × 10–1	6.05 × 10–2	1.23 × 10–1	0.037
cumene (1)	84.5	3.56 × 10–3	2.13 × 10–2	3.0 × 10–3	3.6 × 10–3	2 × 10–3
ethylbenzene (2)	87	2.66 × 10–3	1.84 × 10–2	1.9 × 10–3	3.1 × 10–3	4 × 10–3
toluene (3)	90	5.78 × 10–4	4.7 × 10–3	3.3 × 10–4	4.5 × 10–4	6.3 × 10–4
cyclooctane (16)	95.3	2 × 10–3	1.2 × 10–2	3 × 10–4	6.7 × 10–6
2,3-dimethylbutane (2)	96.5			2.3 × 10–4		1.2 × 10–4
cyclohexane (12)	99.3	3.53 × 10–4	4.33 × 10–3	9.14 × 10–5	6.7 × 10–6	5.5 × 10–5
self-decay		1.17 × 10–5	1.17 × 10–4	2.8 × 10–6	4.3 × 10–6	2.3 × 10–6

^aAll experiments were performed in triplicate, at a minimum.

^bNumbers in parentheses represent the number of H atoms on the substrate that would react with the Fe^IV=O species.

^cD_C–H values were obtained from ref (29).

^dThe k₂’ values used in Figure 16 were obtained by dividing k₂ values listed here by the number of equivalent H atoms on the substrate listed under the alkane substrate column.