Table 1.

Second-order rate constants and KIE values determined in substrate oxidations by [Fe^IV(O)(TMC)(X)]ⁿ⁺ (1-X) and [Fe^IV(O)(TMCS)]⁺ (1′-SR)

Substrate	CH BDE,† kcal/mol	k2, M−1·s−1
		1-NCCH3	1-OOCCF3	1-N3	1′-SR
PPh3	N/A	5.9	2.9	0.61	[0.016]
2,4-t-Bu2C6H3OH	N/A	0.050	0.63	4.3	[12]
Xanthene	75.5	0.39	7.6	9.6
(KIE)‡		(16)	(20)	(17)
DHA	77	0.14 [0.20]	1.3	2.4 [4.9]	[7.5]
(KIE)‡		(10)	(19)	(17)
CHD	78	0.12	1.2	1.4
Fluorene	80	n.d.§	0.051	0.15
Ep,c in CH3CN at 25°C		−0.32	−0.50	−0.60
(1:1 CH3CN/CH3OH at −30°C)		(−0.44)	(−0.62)	(−0.66)	(−1.00)

Rate constants were determined at 0°C in CH₃CN for 1-X or 1:1 CH₃CN/MeOH for 1′-SR. Square brackets designate values obtained in 1:1 CH₃CN/CH₃OH at 0°C. The spectral changes were monitored at 820 nm for 1-NCCH₃, 835 nm for 1-OOCCF₃ and 850 nm for 1-N₃ and 1′-SR. Rate constants are averaged by three determinations, and standard deviation is <10% of the given values. N/A, not applicable.

^†BDE of CH bonds are from refs. 29 and 30.

^‡KIE values were determined at 25°C for 1-NCCH₃ and at 0°C for 1-OOCCF₃ and 1-N₃. See SI Table 3 for k_obs constants determined in the reactions.

^§Not determined due to the low reactivity of the intermediates in the oxidation of fluorene.