Table 1.

Results of COPASI Global Fitting of Stopped-Flow Optical Kinetic Results and Comparison with Experimental Values^a

reaction	parameterb	model	experimentalc
$\text{Fc}*+{\text{Fe}}^{\text{III}}{(\text{TPP})}^{+}\rightleftharpoons {\text{Fc}}^{*+}+{\text{Fe}}^{\text{II}}(\text{TPP})$	KET (298 K)	0.055(7)	0.18(3)
	ΔH°ET	2.9(1)	2.8(1)
	ΔS°ET	4.1(4)	6(2)
FeII(TPP) + O2 ⇌ FeIII(TPP)(${{\text{O}}_2}^{•-}$)	KO2 (250 K, M−1)d	(2.7–6.4) × 104	(0.205–11.5) × 102e
	ΔH°O2	−9.5(1)	−l0.5(7)e
	ΔS°O2	−16.9(4)	−32 (3)e
FeIII(TPP)(${{\text{O}}_2}^{•-}$) + pTsOH → FeIII(TPP)(O2H•)+ + pTsO−	kPT (298 K)	1.5(3)×103 M−1 s−1	2.0(9)f × 105 M−1 s−1
	ΔH‡PT	12.0(1)
	ΔS‡PT	−3.1(2)
FeII(TPP) + O2 + pTsOH → FeIII(TPP)(O2H•)+ + pTsO−g	kcat (298 K, M−2 s−1) = KO2kPT	(2–20) × 105h	(3.2–6.4) × 105i

^aOptimized values from COPASI analysis of data at 253–303 K, 50–100 mM pTsOH, 30–50 μM Fe(TPP). COPASI values and experimental equilibrium parameters are given with the uncertainty in parentheses representing 1 standard deviation.

^b$\mathrm{\Delta }{H}^{°}\text{and}\mathrm{\Delta }{H}^{‡}$ values in kcal mol⁻¹; ΔS° and ΔH° values in cal K⁻¹ mol⁻¹.

^cDirect experimental measurements of equilibrium parameters from optical spectra and van ′t Hoff analyses (sections I and II).

^dValues extrapolated from thermodynamic parameters from kinetic data (model) or lower-temperature equilibrium measurements (experiment).

^eThe 95% confidence limits from a t test are for $K_{{\text{O}}_2}$ at 298 K, 0.21 to 110 M⁻¹; for $\mathrm{\Delta }{H^{°}}_{{\text{O}}_2},$ −9.6 to −11.8 kcal mol⁻¹; and for $\mathrm{\Delta }{S}_{{\text{O}}_2},$ −28 to −38 cal K⁻¹ mol⁻¹, SI Section 3.4).

^fCalculated as $k_{\text{cat}(\text{echem})}/K_{{\text{O}}_2(\text{experimental})},$ where $K_{{\text{O}}_2}$ was defined as the mean value, 5 M⁻¹.

^gChemical steps involved in defining the catalytic rate constant, k_cat, determined electrochemically.

^hCalculated as $K_{{\text{O}}_2}(\text{model})\times k_{\text{PT}}\text{(model)}.$

ⁱCalculated from foot-of-the-wave analysis, vide infra.