. Author manuscript; available in PMC: 2011 Dec 8.

Published in final edited form as: Chem Rev. 2010 Oct 6;110(12):6961–7001. doi: 10.1021/cr100085k

Table 4.

PCET thermochemistry of phenols.^a

Compound	solvent	E(RO^•/−)	E(ROH^•+/0)	pK_a(ROH^•+)	pK_a(ROH)	BDFE	BDE
PhOH	gas	--	--	--	--	79.8⁴⁹	88.0⁴⁹
PhOH	H₂O	0.79¹¹⁷	1.5¹³⁶	[−2] ¹¹⁵	10.0¹³⁷	89.5	87.7
PhOH	DMSO	−0.325¹¹⁶	1.2¹¹⁶	[−7.7]	18.0¹¹⁶	88.3	92.7
PhOH	C₆H₆	--	--	--	--	83.8	88.6¹²¹,^b
4-Me-PhOH	H₂O	0.68¹¹⁷	1.4¹³⁶	[−2] ¹¹⁵	10.3¹³⁷	87.4	85.6
4-Me-PhOH	DMSO	−0.428¹¹⁶	1.1¹¹⁶	[−4]	18.9¹¹⁶	87.1	91.7
4-Me-PhOH	C₆H₆	--	--	--	--	81.7	86.5¹²¹,^b
4-MeO-PhOH	H₂O	0.54¹¹⁷	1.1¹³⁶	[0.7]	10.1¹³⁷	83.9	82.1
4-MeO-PhOH	DMSO	−0.618¹¹⁶	0.85¹¹⁶	[−5.6]	19.1¹¹⁶	83.0	87.6
4- MeO-PhOH	C₆H₆	--	--	--	--	78.3	83.1¹²¹,^b
4-NO₂-PhOH	H₂O	1.22¹¹⁷	--	--	7.1¹³⁷	95.5	93.7
4-NO₂-PhOH	DMSO	0.314¹¹⁶	1.9¹¹⁶	[−9.5]	10.8¹¹⁶	93.1	97.7
4-F-PhOH	H₂O	0.76¹¹⁷	--	--	9.9¹³⁷	88.7	86.9
4-Cl-PhOH	H₂O	0.80¹¹⁷	--	--	9.4¹³⁷	88.9	87.1
4-Cl-PhOH	DMSO	−0.232¹¹⁶	1.4¹¹⁶	[−11]	16.75¹¹⁶	88.7	93.3
4-Br-PhOH	H₂O	0.82¹¹⁷	--	--	9.4¹³⁷	89.4	87.6
4-Br-PhOH	DMSO	−0.19¹¹⁶	1.3¹¹⁶	[−8.7]	16.36¹¹⁶	89.1	93.7
4-I-PhOH	H₂O	0.82¹¹⁷	--	--	9.3¹³⁷	89.3	87.5
4-CO₂⁻-PhOH	H₂O	0.90¹¹⁷	--	--	9.4¹³⁷	91.2	89.4
4-Me(O)C-PhOH	H₂O	1.00¹¹⁷	--	--	8.0¹³⁷	91.6	89.8
4-Me(O)C-PhOH	DMSO	0.04¹¹⁶	1.6¹¹⁶	[−12]	14.0¹¹⁶	91.2	95.8
4-CN-PhOH	H₂O	1.12¹¹⁷	--	--	7.9¹³⁷	94.3	92.5
4-CN-PhOH	DMSO	0.15¹¹⁶	1.7¹¹⁶	[−13]	13.2¹¹⁶	92.6	97.2
4-NH₂-PhOH	H₂O	0.217¹¹⁷	--	--	10.4¹³⁷	76.9	75.0
4-NH₂-PhOH	DMSO	−1.031¹¹⁶	−0.065¹¹⁶	[4.5]	20.75¹¹⁶	75.8	80.4
4-NMe₂-PhOH	H₂O	0.174	--	--	10.1¹³⁷	75.4	73.6
4-NMe₂-PhOH	DMSO	−0.847¹¹⁶	−0.045¹¹⁶	[6.3]	19.8¹¹⁶	78.7	83.3
1-naphthol	H₂O	0.59¹³⁸	--	--	9.3¹³⁸	83.9	82.1
1-naphthol	DMSO	−0.473¹¹⁶	0.95¹¹⁶	[−7.8]	16.2¹¹⁶	82.4	87.0
2-naphthol	H₂O	0.69¹³⁸	--	--	9.6¹³⁸	86.7	84.9
2-naphthol	DMSO	−0.353¹¹⁶	1.0¹¹⁶	[−5.7]	17.1¹¹⁶	86.4	91.0
tyrosine	H₂O	0.71¹¹⁷	[1.4]	~ −2 ¹¹⁵	10.1¹³⁷	87.8	86.0
Trolox C^c	H₂O	0.192¹¹⁸	--	--	12¹³⁹	78.5	76.7
HPMC^d	C₆H₆	--	--	--	--	73.7	78.5¹²¹,^b
TocOH^e	DMSO	−0.87¹⁴⁰	--	--	20.2¹⁴⁰	78.7	83.3
TocOH^e	MeCN	−0.90¹⁴¹	0.6¹⁴¹	[4.7]	30 ¹⁴⁰,^f	75.2	79.7
TocOH^e	C₆H₆	--	--	--	--	73.7	78.5¹²¹,^b
2,4,6-^tBu₃PhOH	H₂O	0.21¹⁴²	1.28¹⁴²	[−5] ¹⁴²	13 ¹⁴²,¹⁴³	80.3	78.5
2,4,6-^tBu₃PhOH	DMSO	−0.645¹¹⁶	1.0¹¹⁶	[−10]	17.8¹¹⁶	80.6	85.2
2,4,6-^tBu₃PhOH	MeCN	−0.70¹⁴⁴,¹⁴⁵,¹⁴⁶	1.18¹⁴⁷	[−3]	28 ¹¹⁶,^f	77.1	81.6
2,4,6-^tBu₃PhOH	C₆H₆	--	--	--	--	76.7	81.6⁴⁰
2,4,6-^tBu₃PhOH	CCl₄	--	--	--	--	77.2	82.0⁴⁰
2,6-^tBu₂PhOH	DMSO	−0.619¹¹⁶	--	--	17.3¹¹⁶	80.5	85.1
2,6-^tBu₂PhOH	C₆H₆	--	--	--	--	78.3	83.1¹²¹,^b
4-Me-2,6-^tBu₃PhOH	DMSO	−0.755¹⁴⁰	--	--	17.7¹⁴⁰	77.9	82.5
4-Me-2,6-^tBu₃PhOH	C₆H₆	--	--	--	--	76.9	81.7¹²¹,^b
4-MeO-2,6-^tBu₃PhOH	DMSO	−0.806¹⁴⁰	--	--	18.2¹⁴⁰	77.4	82.0
4-MeO-2,6-^tBu₃PhOH	C₆H₆	--	--	--	--	73.8	78.6¹²¹,^b

Potentials are in V vs. NHE for aqueous measurements and vs. Cp₂Fe^+/0 in non-aqueous solvents. E° and pK_a values in [square brackets] have been calculated from the other values in the row using Hess’ law (eqs 6, 7). Italicized values are irreversible potentials, E_p,a or E_p,c, measured by cyclic voltammetry. BDFEs (kcal mol⁻¹) are from the cited reference or calculated from E and pK_a values (eqs 7, 15, 16); BDEs (kcal mol⁻¹) are typically calculated from BDFEs using eq 9.

The values reported in reference ¹²¹ are relative to ^tBu₃PhOH. The values given here have been adjusted to reflect our critical re-evaluation of BD(F)E of ^tBu₃PhOH in reference ⁴⁰.

Trolox C = (±)-6-hydroxy-2,5,7,8-tetramethylchromane-2-carboxylic acid.

HPMC = 6-hydroxy-2,2,5,7,8-pentamethylchroman.

TocOH = α-tocopherol.

Extrapolated from DMSO to MeCN using the method of Kütt and coworkers.⁸⁹