Table 2.

Calculated gas phase bond dissociation enthalpies and bond dissociation free energies of the compounds studied together with literature values

Compound	Theoretical gas phase values (kcal mol−1)			Experimental literature values (kcal mol−1)
	BDE	ΔBDE∉	BDFE	BDE	ΔBDE	BDFE
Phenol	87.3	0.0	86.4	86.7 ± 0.727		79.8‡,48
				88.7 ± 0.528		84.9Æ,64
2-Methylphenol (o-cresol)	85.8	1.5	84.9	86.0 ± 0.433	2.233
				86.634	2.234
3-Methylphenol (m-cresol)	87.2 ± 0.0 (n = 2)	0.1	87.1 ± 0.0 (n = 2)	87.6 ± 0.133	0.533
4-Methylphenol (p-cresol)	86.9	0.4	86.5	86.6 ± 0.533	1.733	87.448
				86.834	1.934
2-Methoxyphenol (guaiacol)	83.7 ± 0.0 (n = 2)	3.6	82.9 ± 0.3 (n = 2)	84.2 ± 0.233	4.133
				84.734	4.134
2,6-Dimethoxyphenol	83.8 ± 0.2 (n = 3)	3.7	83.2 ± 0.4 (n = 3)	83.2 ± 0.241	5.141
				83.742	5.042
BHT	75.3	12.0	74.3	79.610	7.710	75.8Æ,64
1-Naphthol	80.5	6.8	79.7	82.133	6.133	75.4‡,64
				82.745	5.545	79.7§,64
2-Naphthol	85.0	2.3	84.1	84.633	2.433	78.7‡,64
				85.645	2.945	83.0§,64
2-hydroxyphenol	81.8	5.6	80.8	81.847	5.847
				81.634	7.234
l-Ascorbic acid	75.4 ± 0.7 (n = 6)	11.9	74.3 ± 0.6 (n = 6)	78.0,48	9.7,48	79.8,48
l-Ascorbate	66.2 ± 1.3 (n = 4)	21.1	65.2 ± 1.2 (n = 4)	71.8,48	15.9,48	73.6,48
				72.3Π,48		67.7Π,48
				72.2Θ,48	20.4Θ,48	67.6Θ,48
5,6-isopropylidene-l-ascorbic acid	76.0	11.3	74.8	75.1Π,48		70.5Π,48
5,6-Isopropylidene-l-ascorbate	67.3	20.0	66.0	70.0Π,48		65.4Π,48
				72.1Θ,48	20.6Θ,48	67.5Θ,48
6,7-Dihydroxyflavone	81.9 (6-OH)	5.4	80.2 (6-OH)	79.449	8.849
	79.7 (7-OH)	7.6	77.9 (7-OH)
7,8-Dihydroxyflavone	81.0 (7-OH)	6.3	79.9 (7-OH)	79.649	8.649
	79.6 (8-OH)	7.7	77.4 (8-OH)
5,7-Dihydroxyflavone	81.7 (5-OH)	5.6	80.3 (5-OH)	85.349	2.849
	88.9 (7-OH)	−1.6	87.2 (7-OH)
Luteolin	81.9 ± 0.1 (n = 8) (3′-OH)	5.4	81.1 ± 0.2 (n = 8) (3′-OH)	81.949	6.349
	78.0 ± 0.3 (n = 8) (4′-OH)	9.3	77.2 ± 0.2 (n = 8) (4′-OH)
Hesperetin	83.5 ± 0.4 (n = 8) (3′-OH)	3.8	82.6 ± 0.3 (n = 8) (3′-OH)	84.649	3.649

^∉ΔBDE = BDE_phenol – BDE_X

^‡Gas; ^ÆAlkane; Water; ^§Isopentane; ^ΠMeCN; ^ΘDMSO.