doi.org/10.1002/ejoc.202001649

Strengths of Acids in Acetonitrile

Dedicated to the memory of Prof. Ilmar A. Koppel.

Agnes Kütt, Sofja Tshepelevitsh, Jaan Saame, Märt Lõkov, Ivari Kaljurand, Sigrid Selberg, and Ivo Leito*

Eur. J. Org. Chem. 2021, 1407−1419

HI

4−Cl−C6H4−SO(=NTf)−NH−SO2−C6H4−4−NO2

2,3,5−Tricyanocyclopentadiene

2,4−(NO2)2−C6H3−SO3H

4−Cl−C6H4−SO(=NTf)−NH−SO2−C6H4−4−Cl

4−NO2−C6H4−SO2−NH−Tf

(CN)2C=C(CN)OH

2,4,6−Tf3−Phenol

4−NO2−C6H4−C(=NTf)−NH−Tf

4−Cl−C6H4−SO(=NTf)−NH−Tos

[3,5−(CF3)2−C6H3]−JINGLE

4−Cl−C6H4−SO2−NH−Tf

CH(CN)3

(C6F5−SO2)2NH

4−Cl−C6H4−C(=NTf)−NH−Tf

2,4,6−(SO2F)3−Phenol

4−F−C6H4−C(=NTf)−NH−Tf

HBr

C6H5−SO2−NH−Tf

H−TCNP

C6H5−C(=NTf)−NH−Tf

4−Me−C6H4−C(=NTf)−NH−Tf

Tos−NH−Tf

4−NO2−C6H4−SO2−CH(CN)2

4−MeO−C6H4−C(=NTf)−NH−Tf

C6F5−SO2−NH−SO2−C6H3−3−NO2−4Cl

3−NO2−C6H4−SO2−CH(CN)2

[4−F−C6H4][CF3]−NTPA−[H8]

4−NO2−C6H4−SO3H

[Ph][CF3]−NTPA

[4−MeO−C6H4][CF3]−NTPA

3−NO2−C6H4−SO3H

C6F5−SO2−NH−SO2−C6H4−4−NO2

[Ph][C4F9]−NTPA−[H8]

C6F5−SO2−NH−SO2−C6H4−3−NO2

[Ph][CF3]−NTPA−[H8]

[Ph][C8F17]−NTPA−[H8]

[4−MeO−C6H4][CF3]−NTPA−[H8]

4−Cl−C6H4−SO3H

Me−TCNP

(4−Cl−3−NO2−C6H3−SO2)2NH

C6F5−SO2−NH−SO2−C6H4−4−Cl

H2SO4

C6H5−CHTf2

4−NO2−C6H4−SO2−NH−SO2−C6H3−3−NO2−4−Cl

3−NO2−C6H4−SO2−NH−SO2−C6H3−3−NO2−4−Cl

1−C10H7−SO3H

2,4,6−(SO2OCH2CF3)3−Phenol

2,4,6−(SO2OCH2CF2CF2H)3−Phenol

(4−NO2−C6H4−SO2)2NH

(3−NO2−C6H4−SO2)2NH

Ph−SO3H

TosOH

4−Cl−3−NO2−C6H3−SO2−NH−SO2−C6H4−4−Cl

[2,3,4,5,6−(CF3)5−C6]2NH

2,3,4,5,6−(CF3)5−C6−CH(CN)2

4−NO2−C6H4−SO2−NH−SO2−C6H4−4−Cl

4−NO2−C6H4−CO−NH−Tf

2,4−(NO2)2−C6H3−CH(CN)2

4−Cl−3−NO2−C6H3−SO2−NH−Tos

Me−SO3H

4−NO2−C6H4−SO2−NH−Tos

3−NO2−C6H4−SO2−NH−Tos

2,3,4,5,6−(CF3)5−Thiophenol

4−CF3−C6F4−CH(CN)2

(4−Cl−C6H4−SO2)2NH

4−MeO−C6H4−SO2−NH−SO2−C6H4−4−NO2

HCl

4−Cl−C6H4−CO−NH−Tf

2,3,4,6−(CF3)4−C6H−CH(CN)2

2,3,4,5,6−(CF3)5−Phenol

(2,4,6−(NO2)3−C6H2)2NH

4−F−C6H4−CO−NH−Tf

5−NO2−Barbituric acid

Picric acid

C6H5−CO−NH−Tf

4−Cl−C6H4−SO2−NH−Tos

C6F5−NH−SO2−C8F17

C6F5−NH−SO2−C4F9

4−MeO−C6H4−SO2−NH−SO2−C6H4−4−Cl

(C6H5−SO2)2NH

4−Me−C6H4−CO−NH−Tf

C6F5−NH−Tf

4−MeO−C6H4−CO−NH−Tf

4−NO2−C6H4−CH(CN)2

RS−3,5−(CF3)2−Ph−CXCC−Br4−benzoic acid

Ph−SO2−NH−SO2−Me

Tos2NH

2−C10F7−CH(CN)2

3,5−(CF3)2−Ph−CACC−Br4−benzoic acid

[4−F−C6H4]−BPA

3−CF3−4−NO2−Ph−CACC−Br4−benzoic acid

[Ph]−BPA

4−H−C6F4−CH(CN)2

C6F5−CH(CN)2

[9−Phenanthrene]−BPA

2,3,4,5,6−(CF3)5−C6−CH(CN)COOEt

(4−NC5F4)2CHCN

RR−3,5−(CF3)2−Ph−CXCC−Br4−benzoic acid

[2,4,6−i−Pr3−C6H2]−BPA

4−Me−C6F4−CH(CN)2

[9−Phenanthrene]−BPA−[H8]

2−Cl−4,6−(NO2)2−Phenol

4−NO2−C6H4−SO2−NH−CO−C6H4−3−Cl

3−NO2−C6H4−SO2−NH−CO−C6H4−3−Cl

Saccharin

3−CF3−C6H4−CH(CN)2

4−NC5F4−CH(CN)COOEt

4−NC5F4−OH

4−NO2−C6H4−SO2−NH−CO−C6H4−4−Me

(4−NC5F4)(2−C10F7)CHCN

4−CF3−C6F4−CH(CN)COOEt

(4−CF3−C6F4)2CHCN

4−F−2,6−(NO2)2−Phenol

(4−NC5F4)(C6F5)CHCN

4−CF3−2,3,5,6−F4−Phenol

2,4−(NO2)2−Phenol

2,6−(NO2)2−Phenol

2−Me−4,6−(NO2)2−Phenol

Br4−CX−benzoic acid

(4−NC5F4)2NH

4−Cl−C6F4−CH(CN)COOEt

2−C10F7−CH(CN)COOEt

4−Me−C6H4−CH(CN)2

C6F5−CH(CN)COOEt

2,3,4,5,6−Br5−Phenol

2,3,4,5,6−Cl5−Phenol

4−H−C6F4−CH(CN)COOEt

Br4−CF3−CAC−benzoic acid

4−C6F5−2,3,5,6−F4−Phenol

(4−CF3−C6F4)(C6F5)CHCN

(4−NC5F4)(4−CF3−C6F4)NH

[4−(Ph3B)−2,6−Mes2−Pyridine]H

2−C10F7−OH

9−C6F5−Octafluorofluorene

Br4−CA−benzoic acid

(2−C10F7)2CHCN

2,4,6−(SO2F)3−Aniline

1−C10F7−OH

(4−CN−C6F4)(C6F5)NH

(2−C10F7)(C6F5)CHCN

2,3,4,5,6−F5−Phenol

2,3,5,6−F4−Phenol

(2,4,6−Cl3−C6F2)(C6F5)CHCN

2,3,4,5,6−(CN)5−Toluene

2,4,6−Br3−Phenol

(4−Cl−C6F4)(C6F5)CHCN

(4−NC5F4)(C6F5)NH

(CF3)3COH

4−CF3−C6F4−CH2−Tf

(C6F5)2CHCN

(4−H−C6F4)(C6F5)CHCN

Alizarin

9−CN−Fluorene

(4−CF3−C6H4)(C6F5)NH

Benzoic acid

4−NO2−C6H4−CH2−Tf

(4−Me−C6F4)(C6F5)CHCN

C6F5−SO2−NH2

3−NO2−Indole

Retinoic acid

(4−Me−C6F4)2CHCN

3,5−(CF3)2−C6H3−CH2−Tf

2−NO2−Phenol

C6F5−CH(COOEt)2

Sorbic acid

4−CN−C6H4−CH2−Tf

(4−Cl−C6F4)(C6F5)NH

Acetic acid

9−COOMe−Fluorene

2−NO2−Indole

3,5−(CF3)2−Phenol

2,4,6−(NO2)3−Aniline

Fluoradene

3,5−F2−C6H3−CH2−Tf

(C6F5)2NH

C6F5−NH−C(CF3)3

(4−H−C6F4)(C6F5)NH

3,5−(CF3)2−Ph−C−thiourea

4−CF3−C6H4−CH2−Tf

Octafluorofluorene

3−CN−C6H4−CH2−Tf

4−NO2−C6H4−SO2−NH2

2,3,4,5,6−(CF3)5−Aniline

3−NO2−C6H4−SO2−NH2

1,3−Bis(4−NO2−C6H4)urea

2−CF3−Phenol

(4−Me−C6F4)(C6F5)NH

3−CF3−C6H4−CH2−Tf

(4−Me2N−C6F4)(C6F5)NH

3−CF3−C6H4−SO2−NH2

4−CF3−C6H4−SO2−NH2

3−Cl−C6H4−CH2−Tf

4−CF3−Phenol

3−F−C6H4−CH2−Tf

Triazine 1

4−Cl−C6H4−SO2−NH2

3−CN−Indole

(Ph)(C6F5)CHCN

SBoxCH2

4−F−C6H4−SO2−NH2

4−NO2−Indolocarbazole

(4−NO2−C6H4)2NH

(Ph)(4−NC5F4)NH

C6F5−NH−COMe

3−CF3−Phenol

Triazine 2

Ph−SO2−NH2

(4−NC5F4)(4−Me−C6H4)NH

Box2CH2

4−Me−C6H4−SO2−NH2

(Ph)(4−Me−C6F4)CHCN

4−F−C6H4−CH2−Tf

4−Cl−C6H4−CH2−Tf

1,2,3,4−F4−9−Ph−Fluorene

C6H5−CH2−Tf

(3,5−(CF3)2−C6H3)3COH

Me2Box2CH2

6−NO2−Indole

4−NO2−Indole

1−(4−Cl−C6H4)−3−(3,4−Cl2−C6H3)urea

9−C6F5−Fluorene

5−NO2−Indole

2,3,4,5,6−(CF3)5−Toluene

4−CN−2,3,5,6−F4−Aniline

tBu4Box2CH2

Phenol

Indoxyl acetate

7−NO2−Indole

Triazine 3

Indole

Compound

0.58

1.01

0.88

0.90

1.06

1.15

0.63

0.19

0.82

2.58

−0.03

0.53

0.68

0.58

0.02

0.45

0.90

0.38

0.06

1.16

0.96

0.32

0.39

2.61

1.79

1.05

0.02

0.39

0.73

2.70

0.90

0.92

0.89

1.01

1.49

0.25

0.26

1.57

0.90

0.54

2.21

2.10

0.76

0.96

0.21

0.25

0.21

0.48

1.07

1.88

0.06

0.19

0.80

0.08

0.26

0.59

0.10

1.81

0.81

1.73

2.30

1.21

1.48

0.92

0.82

0.26

1.87

1.15

0.27

0.54

0.05

0.06

0.84

0.41

1.12

1.43

0.15

1.04

0.71

0.40

1.89

0.44

0.87

0.90

1.01

1.71

0.03

0.74

1.02

0.93

0.48

1.59

1.37

0.74

0.87

1.60

0.26

1.10

0.35

1.10

0.62

0.03

1.77

1.16

0.90

1.89

0.87

0.19

1.08

0.72

0.61

1.06

1.35

0.28

1.10

0.87

2.06

0.71

2.11

0.10

1.29

0.10

1.06

1.75

1.15

1.74

1.81

1.82

0.46

1.08

0.13

1.15

−0.01

1.20

1.30

1.30

0.82

0.82

1.12

2.00

1.24

0.93

1.06

0.15

0.79

2.12

0.14

1.02

1.52

0.52

0.88

0.73

1.63

1.46

1.05

0.32

1.28

0.59

1.11

0.37

0.83

0.00

0.01

0.20

0.85

1.08

0.31

1.31

1.14

0.85

0.42

1.39

0.48

1.57

1.92

0.41

1.22

2.56

1.48

1.70

1.37

1.94

1.13

0.92

0.79

0.23

1.91

1.74

0.16

0.36

0.380.26

0.59

0.83

0.53

0.47

0.77

0.64

0.90

1.68

1.13

0.94

1.70

0.95

1.73

1.46

1.25

0.42

0.41

0.05

0.78

1.88

0.81

0.71

0.76

0.74

1.04

1.00

0.64

0.25

1.18

1.83

0.08

0.18

1.27

1.21

1.30

1.23

1.12

0.14

1.78

0.04

1.96

0.85

1.13

1.50

0.97

1.96

1.48

1.03

1.54

1.20

1.53

0.97

0.64

0.04

0.44

0.42

0.58

1.28

0.35

0.68

0.67

0.71

0.04

0.60

0.72

0.75

0.26

0.06

0.43

0.44

0.78

1.19

0.28

0.41

0.75

0.81

0.92

0.27

0.32

0.37

0.98

1.51

1.92

0.12

0.39

0.45

0.89

0.79

1.08

1.38

0.14

0.29

0.36

0.53

0.72

0.79

0.91

0.30

0.05

0.13

0.70

1.15

0.53

0.10

0.20

1.020.69

1.02

1.22

1.09

0.62

0.69

1.27

2.26

0.18

0.35

0.33

0.47

0.64

0.96

0.42

0.59

0.38

0.88

1.20

0.41

0.31

1.20

0.20

0.17

1.25

1.31

1.17

0.78

0.43

0.11

0.88

0.02

1.02

1.84

0.73

1.10

0.60

1.49

0.69

0.04

0.89

0.60 0.60

1.43

0.53

0.94

0.56

0.46

0.600.62

0.30

0.39

0.51

1.31

0.05

0.50

0.52

0.72

0.76

0.53

0.72

−0.01 1.03

0.34

1.35

0.48

1.21

0.24

0.32

0.23

0.70

0.09

0.13

1.74

0.23

0.71

0.29

1.32

0.98

0.13

1.25

0.06

0.19

0.49

0.54

1.72

1.64

0.07

0.15

1.60

1.37

0.57

0.27

0.06

0.65

0.280.12

0.88

0.85

1.21

1.06

0.73

0.41

0.47

0.49

0.63

0.53

0.40

0.20

0.00

0.20

0.93

0.31

0.29

0.60

0.71

0.57

0.38

0.10

0.10

1.49

0.97

0.18

0.10

−0.01

0.10

0.97

0.71

0.03

0.53

0.42

0.16

0.53

0.03

1.02

0.03

0.40

1.05

0.38

0.36

0.04

0.21

0.63

0.61

0.91

0.69

0.77

0.22

1.410.70

0.69

1.00

0.75 0.56

0.22

1.02

1.68

1.26

1.20

0.77

1.89

1.65

0.28

0.37

0.80

0.56

0.07

0.23

0.07

0.25

0.19

1.40

0.54

0.56

0.66

0.65

0.64

0.53

0.51

0.45

0.33

0.17 0.44

0.57

0.6

0.14

0.06

0.91

0.14

0.84

0.53

0.32

0.27

0.30

0.78

0.78

0.18

0.51

0.50

−0.01

0.13

1.45

0.48

0.80

0.27

0.32

0.00

0.01

0.40

0.79

0.20

0.41

1.01

0.88

0.72

0.17

0.45

0.11

1.91

0.22

0.22

1.08

0.47

0.23

0.21

0.21

0.15

0.17

0.65

0.53

0.47

0.39

0.08

0.16

0.09 0.51

0.72

0.2

0.47

0.07

0.80

0.16

0.24

0.31

0.98

0.07

0.10

0.34

0.54

0.84

0.11

0.79

0.21

0.07

0.64

0.14

0.30

0.36

0.32

0.02

0.97

0.11

0.31

0.75

0.6

0.29

0.46

0.46

0.86

0.50

0.62

2.8

3.30

3.65

3.96

4.00

4.04

4.36

4.44

4.63

4.78

4.97

4.98

5.0

5.08

5.20

5.22

5.29

5.4

5.52

5.64

5.68

5.82

5.82

6.01

6.05

6.16

6.16

6.22

6.3

6.33

6.35

6.4

6.60

6.65

6.68

6.68

6.69

6.83

7.0

7.36

7.47

7.55

7.6

7.73

7.82

7.84

7.9

7.94

8.14

8.15

8.16

8.2

8.5

8.75

8.76

8.88

9.17

9.49

9.58

9.68

9.97

10.04

10.07

10.12

10.19

10.20

10.29

10.3

10.35

10.42

10.46

10.54

10.65

10.72

11.00

11.07

11.10

11.19

11.25

11.29

11.35

11.46

11.48

11.60

11.61

11.80

11.89

11.97

12.23

12.40

12.46

12.69

12.73

12.98

13.01

13.32

13.41

13.47

13.55

13.63

13.87

13.97

14.23

14.43

14.55

14.57

14.70

14.89

15.39

15.68

16.01

16.07

16.12

16.17

16.39

16.6

16.65

16.74

16.97

17.19

17.20

17.38

17.48

17.57

17.73

17.81

18.00

18.07

18.1

18.1

18.13

18.25

18.45

18.5

18.87

19.20

19.32

19.66

19.7

19.87

20.07

20.1

20.1

20.13

20.14

20.34

20.36

20.39

20.5

21.02

21.09

21.10

21.23

21.35

21.37

21.5

21.92

21.94

22.27

22.77

22.78

22.80

22.84

22.85

22.88

22.97

23.19

23.22

23.5

23.54

23.64

23.8

23.87

23.92

23.96

23.98

24.03

24.11

24.31

24.44

24.49

24.51

24.57

24.57

24.63

24.71

24.9

24.96

25.08

25.13

25.20

25.24

25.47

25.5

25.62

25.85

25.85

26.01

26.16

26.16

26.16

26.18

26.18

26.36

26.45

26.5

26.58

26.63

26.87

26.89

26.95

26.98

27.00

27.06

27.12

27.19

27.21

27.59

27.79

27.89

27.95

28.14

28.18

28.77

28.78

28.85

29.2

29.97

29.99

30.86

32.57

pKa Directly measured ∆pK a

3.5

2.9

2.9

2.9

3.4

2.9

3.2

2.9

3.8

3.6

4.0

3.8

3.3

4.2

4.2

4.8

3.9

4.5

5.0

5.0

5.0

5.0

5.0

logKAHA

Acid type: CH−acids OH−acids NH−acids SH−acids Hydrogen halides