Table 1.

Computed bond dissociation enthalpy (BDE) and adiabatic ionization potential (IP) values for nitrones in the gas phase and in acetonitrile (MeCN) used to estimate the thermodynamic feasibility of SET and HAT mechanisms (quantities in Kcal/mol).

Compound		IP		EA		BDE1		SET		HAT
		Gas Phase	MeCN	Gas Phase	MeCN	Gas Phase	MeCN	Gas Phase	MeCN	Gas Phase
Nitrone 1	ΔE	174.91	134.29	−23.82	−64.44	66.04	73.12	99.59	22.47	−12.13
	ΔH	174.91	134.29	−23.82	−64.44	66.64	73.71	99.59	22.47	−12.13
	ΔG	174.19	134.29	−24.52	−64.94	57.96	65.12	98.67	22.57	−12.90
Nitrone 2	ΔE	176.22	135.48	−27.27	−66.18	66.41	73.67	100.90	23.66	−11.76
	ΔH	176.22	135.48	−27.27	−66.18	67.00	74.26	100.90	23.66	−11.76
	ΔG	175.59	134.67	−28.19	−67.36	58.21	65.64	100.07	24.05	−12.65
Nitrone 3	ΔE	176.95	135.84	−32.46	−69.65	65.53	73.00	101.63	24.03	−12.64
	ΔH	176.95	135.84	−32.46	−69.65	66.12	73.59	101.63	24.03	−12.64
	ΔG	176.41	135.15	−32.95	−69.83	57.59	65.26	100.88	24.52	−13.27
DPPH	ΔE	163.50	121.78	−75.32	−111.81	−78.17 2	n.d.3	-	-	-
	ΔH	163.50	121.78	−75.32	−111.81	−78.76 2	n.d. 3	-	-	-
	ΔG	164.04	123.92	−75.53	−110.62	−70.87 2	n.d. 3	-	-	-

¹ Referred to the formation of radical 8 in Scheme 2; ² referred to the formation of DPPH-H from DPPH; ³ not determined: it was not possible to obtain a convergence in the DPPH-H geometry optimization with the model chemistry employed.