Table 4.

Energetic parameters, Mulliken charges, and spin populations of the transition states and products in the S and T spin states

	xcTDO		hIDO
	S	T	SS	T
Eact	+11.2 (5.3)	+8.1 (7.6)	+15.5	+13.8
ΔE	−12.1 (−12.6)	−21.7 (−21.9)	−9.2	−16.2
ΔEspin (product)	+10.8	0	+7.7	0

	Mulliken charge
	TS	P	TS	P	TS	P	TS	P
Fe	+0.830	+0.791	+0.840	+0.797	+0.837	+0.799	+0.853	+0.806
O2	−0.488	–	−0.534	–	−0.519	–	−0.546	–
2,3-Alkyl epoxide	–	−0.318	–	−0.317	–	+0.063	–	+0.064
Ferryl-Hprox	–	+0.060	–	+0.058	–	−0.067	–	−0.068
H55	+0.198	+0.258	+0.273	+0.256	–	–	–	–

	Spin population
	TS	P	TS	P	TS	P	TS	P
Fe	−0.006	+0.001	+0.914	+1.255	+0.891	+0.001	+1.005	+1.252
O2	+0.002	–	+0.434	–	−0.124	–	+0.274	–
2,3-Alkyl epoxide	–	+0.002	–	+0.007	–	+0.001	–	+0.006
Ferryl-Hprox	–	+0.009	–	+1.996	–	+0.000	–	+1.998

E_a and ΔE (kcal/mol) are the activation energies and total reaction energies associated with the Fe³⁺–O²⁻ + L-Trp → Fe⁴⁺=O²⁻ + 2,3-alkyl epoxide reaction along the singlet or triplet reaction coordinate. Values in parentheses for xcTDO correspond to those obtained with a larger basis. ΔE_spin (product) is the energy of the product, 2,3-alkyl epoxide + ferryl-H_prox, in the two spin states, obtained by using that of the triplet state as a reference

TS transition state, P product state, H_prox proximal His ligand