pKa values and gas-phase acidities of superacid molecul

What is a superacid?
• Superacidic medium:
A Brønsted superacid is a medium, in
which the chemical potential of the proton
is higher than in pure sulfuric acid
D. Himmel et al, Angew. Chem. Int. Ed. 2010, 49, 6885
7
What is a superacid?
• Superacidic molecule:
Superacidic molecule in a given medium is
one that is more acidic than H 2 SO 4 in that
medium
8
4

Whydoweneed aciditydata?
• Acidity is a core parameter of an acidic
molecule
• Rationalization and prediction of
mechanisms of chemical and industrial
processes
• Design of novel acids and bases
• Development of theoretical calculation
methods
9
How to measure solution acidities of
highly acidic molecules?
• H 0 scale
• The classical approach
• Different H 0
refer to different media
• H 0
is rather a characteristic of a medium than of a
molecule
• X-H vibrational frequencies
• Indirect: characterizes
hydrogen bond rather than acidity
Stoyanov, et al JACS, 2006, 128, 8500
• Equilibrium measurement (pK a ) in a low
basicity solvent
• Obvious, butalmostunusedappraoch!
10
5

Solvent
• As low basicity as possible
• As high ε as possible
• As high pK auto as possible
• Easy to purify, reasonably inert, electrochemically
stable, transparent in UV, readily available, widely
used
• There is no ideal solvent
• Wth increasing ε as a rule basicity also increases
• Water cannot be used
11
Non-aqueous pK a values: not trivial
• Processes are often more complex than
simple ionic dissociation
• Ion-pairing, homoconjugation, …
• Measurement of a(SH + ) is not trivial
• Traces of moisture can significantly affect
results
K. Kaupmees et al, J. Phys. Chem. A
2010, 114, 11788
• Working in an inert gas atmosphere (glovebox) is
necessary
12
6

Acid-base reaction in a non-aqueous
solvent
K 1 K 2 K 3
(AH) S + (:B) S (AH⋅⋅⋅:B) S (A¯:⋅⋅⋅HB + ) S or (A¯: HB + ) S
HB complex HB complex contact ion pair
K 3 K 4
(A¯: // HB + ) S (A¯:) S + (HB + ) S
solvent-separated ion pair free ions
13
Approach: Relative measurement
• Measurement of pK a differences
• ΔpK a
values
• No need to measure a(SH + ) in solution
• Many of the error sources cancel out,
either partially or fully
• Traces of moisture
• Impurities in compounds
• Baseline shifts and drifts
• Technique: UV-Vis spectrometry
14
7

UV-Vis ΔpK a measurement
Compound 1 Compound 2
Absorbance (AU)
Absorbance (AU)
2
1.8
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
0
anion
neutral
190 240 290 340 390
wavelength (nm)
Mixture
2
1.8
1.6
1.4
1.2
1
0.8
0.6
0.4
anion
NC
NC
CN
CN
CN
OH
CF 2 SO 2
CN SO 2 CF 3
0.2
neutral
0
190 240 290 340 390
wavelength (nm)
SO 2 CF 3
Absorbance (AU)
2
1.8
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
neutral
190 240 290 340 390
wavelength (nm)
0
ΔpK
a
= 0.87
= pK
a
anion
(HA ) − pK
(HA )
-
[A1]
⋅[HA2]
= − log K = log
-
[HA ] ⋅[A
]
2
CF 2 SO 2
SO 2 CF 3
1
a
OH
2
SO 2 CF 3
1
15
Acetonitrile (MeCN)
• Advantages of MeCN:
• Low basicity (B' = 160), low anion-solvating ability →
quite strong acids measurable
• High polarity (ε = 36)
• High pK auto
(≥ 33)
• Transparent in UV, easy to purify, reasonably inert,
electrochemically stable, readily available, widely used
• Limitations:
• Very strong bases decompose MeCN
• Already Et-P2(pyrr) slowly decomposes MeCN
• Impossible to study the strongest superacids
16
8

Self-consistent acidity
scale in MeCN
Acid pK a (AN) a Directly measured ΔpK a b
1 9-C 6F 5-Fluorene 28.11
2 (4-Me-C 6F 4)(C 6H 5)CHCN 26.96
3 (4-NC 5F 4)(C 6H 5)NH 26.34
4 (C 6H 5)(C 6F 5)CHCN 26.14
5 (4-Me 2N-C 6F 4)(C 6F 5)NH 25.12
6 (4-Me-C 6F 4)(C 6F 5)NH 24.94
7 Octafluorofluorene 24.49
8 Fluoradene 23.90
9 9-COOMe-Fluorene 23.53
10 Acetic acid 23.51
11 (C 6F 5)CH(COOEt) 2 22.85
12 2-NO 2-Phenol 22.85
13 (4-Me-C 6F 4) 2CHCN 22.80
14 (4-Me-C 6F 4)(C 6F 5)CHCN 21.94
15 Benzoic acid 21.51
16 9-CN-Fluorene 21.36
17 (4-H-C 6F 4)(C 6F 5)CHCN 21.11
18 (C 6F 5) 2CHCN 21.10
19 (CF 3) 3COH 20.55
20 (4-Cl-C 6F 4)(C 6F 5)CHCN 20.36
21 2,4,6-Br 3-Phenol 20.35
22 (2,4,6-Cl 3-C 6F 2)(C 6F 5)CHCN 20.13
23 2,3,5,6-F 4-Phenol 20.12
24 2,3,4,5,6-F 5-Phenol 20.11
25 (2-C 10F 7)(C 6F 5)CHCN 20.08
26 1-C 10F 7OH 19.72
27 2,4,6-(SO 2F) 3-Aniline 19.66
28 (2-C 10F 7) 2CHCN 19.32
29 9-C 6F 5-Octafluorofluorene 18.88
30 2-C 10F 7OH 18.50
31 (4-CF 3-C 6F 4)(C 6F 5)CHCN 18.14
32 4-C 6F 5-2,3,5,6-F 4-Phenol 18.11
33 (4-H-C 6F 4)CH(CN)COOEt 18.08
34 2,3,4,5,6-Cl 5-Phenol 18.02
35 2,3,4,5,6-Br 5-Phenol 17.83
36 (C 6F 5)CH(CN)COOEt 17.75
37 4-Me-C 6H 4CH(CN) 2 17.59
38 (2-C 10F 7)CH(CN)COOEt 17.50
39 (4-Cl-C 6F 4)CH(CN)COOEt 17.39
40 2,4-(NO 2) 2-Phenol 16.66
41 4-CF 3-2,3,5,6-F 4-Phenol 16.62
42 (4-NC 5F 4)(C 6F 5)CHCN 16.40
43 (4-CF 3-C 6F 4) 2CHCN 16.13
44 (4-CF 3-C 6F 4)CH(CN)COOEt 16.08
45 (4-NC 5F 4)(2-C 10F 7)CHCN 16.02
46 4-NC 5F 4-OH 15.40
47 (4-NC 5F 4)CH(CN)COOEt 14.90
1.15
0.63
0.20
1.03
0.64
0.96
0.67
0.90
0.60
1.01
0.21
0.42
0.40
0.44
0.38
0.36
0.06
0.59
1.49
1.32
1.96
1.20
0.45
0.58
1.05
0.92
0.42
0.39
1.02
0.01
0.43
0.34
1.19
0.75
0.77
0.22
0.32
0.06
1.12
019
1.78
0.17
-0.01
1.49
0.25
0.76
0.81
0.79
0.46
0.19
0.08
1.10
0.60
1.35
0.82
0.68
0.04
0.26
0.53
0.26
0.03
0.03
0.85
0.73
0.04
1.15
0.54
1.43
0.73
0.75
0.71
0.48 1.02
0.41
0.92
1.92
1.59
0.10
0.27
0.27
0.05
0.70
0.69
1.75
1.70
1.51
1.21
0.63
0.88
0.37
-0.01
0.82
1.46
0.72
1.03
0.26
1.02
0.28
0.29
0.25
0.00
0.80
0.06
1.32
47 (4-NC 5F 4)CH(CN)COOEt 14.90
0.69
0.19
48 3-CF 3-C 6H 4CH(CN) 2 14.72
0.15
49 Saccharin 14.57 0.84
0.71
1.89
50 4-Me-C 6F 4CH(CN) 2 13.87
0.40
51 (4-NC 5F 4) 2CHCN 13.46
0.87
0.45 0.89
52 C 6F 5CH(CN) 2 13.01
0.48
0.03 0.04
53 4-H-C 6F 4CH(CN) 2 12.98
0.79
0.74
54 2-C 10F 7CH(CN) 2 12.23
1.38 0.26
55 Tos 2NH c 11.97 0.62
56 4-NO 2-C 6H 4CH(CN) 2 11.61
0.03
57 4-MeO-C 6H 4C(=O)NHTf d 11.60
0.28
0.19 0.14
58 4-Me-C 6H 4C(=O)NHTf 11.46
1.21
0.98
59 (C 6H 5SO 2) 2NH 11.34 0.60
0.60
0.57
60 4-Cl-C 6H 4SO 2NHTos 11.10
0.49
0.36
61 C 6H 5C(=O)NHTf 11.06
1.43
0.10
0.07
62 Picric acid 11.00
63 4-F-C 6H 4C(=O)NHTf 10.65
0.91
0.79
0.87
64 4-Cl-C 6H 4C(=O)NHTf 10.36 0.82
0.54
65 (4-Cl-C 6H 4SO 2) 2NH 10.20
0.15
0.56
-0.01
66 4-CF 3-C 6F 4CH(CN) 2 10.19
0.13
1.15
0.14
67 4-NO 2-C 6H 4SO 2NHTos 10.04 0.52
1.20
1.06
0.73
68 4-Cl-3-NO 2-C 6H 3SO 2NHTos 9.71 1.05 0.46
69 4-NO 2-C 6H 4C(=O)NHTf 9.49 0.53
0.23
70 4-NO 2-C 6H 4SO 2NHSO 2C 6H 4-4-Cl 9.17
2.3
0.56 1.73
71 TosOH 8.6
1.21 0.23
72 (4-NO 2-C 6H 4SO 2) 2NH 8.32
1.3
0.25
73 1-C 10H 7SO 3H 8.02
0.50
0.19 1.04
74 C 6H 5CHTf 2 7.85
0.54 1.25
75 4-Cl-C 6H 4SO 3H 7.3
0.53
76 3-NO 2-C 6H 4SO 3H 6.78 0.51
77 4-NO 2-C 6H 4SO 3H 6.73
78 4-MeO-C 6H 4C(=NTf)NHTf 6.54 0.51
0.44 1.28 0.23
79 4-Me-C 6H 4C(=NTf)NHTf 6.32
0.75 0.23
0.05
0.62
80 TosNHTf 6.30
0.5
0.16 0.35
81 C 6H 5C(=NTf)NHTf 6.17 0.36
1.11 0.47
82 C 6H 5SO 2NHTf 6.02
0.59
0.26
83 4-F-C 6H 4C(=NTf)NHTf 5.79 0.83
1.64
84 4-Cl-C 6H 4C(=NTf)NHTf 5.69
0.77
1.37
85 2,4,6-(SO 2F) 3-Phenol 5.66
1.25
0.64
86 4-Cl-C 6H 4SO 2NHTf 5.47
0.42
0.59
0.71
87 4-Cl-C 6H 4SO(=NTf)NHTos 5.27
0.53
88 4-NO 2-C 6H 4C(=NTf)NHTf 5.13 0.38
1.20
89 2,4,6-Tf 3-Phenol 4.93
0.41
1.1
90 4-NO 2-C 6H 4SO 2NHTf 4.52
0.05
0.87
91 4-Cl-C 6H 4SO(=NTf)NHSO 2C 6H 4-4-Cl 4.47 1.10 1.15
0.31
92 2,3,5-tricyanocyclopentadiene 4.16
0.74
0.50
93 4-Cl-C 6H 4SO(=NTf)NHSO 2C 6H 4-4-NO 2 3.75
A. Kütt et al, J. Org. Chem. 2006, 71, 2829
17
A. Kütt et al, J. Org. Chem. 2011, 76, 391
Properties of the MeCN acidity scale
• Consistency, checked by circular
validation measurements:
• 93 acids, 203 relative acidity measurements
• Consistency standard deviation: 0.03 pK a
units
• Anchored to Picric acid (pK a = 11.0)
• pK a range: 3.7 .. 28.1
• Useful tool for further studies
• Acids in the lower part are superacids
• pK a
(H 2
SO 4
) ≈ 8 in MeCN
18
9

67 4NO 2 C 6 H 4 SO 2 NHTos 10.04
68 4-Cl-3-NO 2 -C 6 H 3 SO 2 NHTos 9.71
69 4-NO 2 -C 6 H 4 C(=O)NHTf 9.49
70 4-NO 2-C 6H 4SO 2NHSO 2C 6H 4-4-Cl 9.17
71 TosOH 8.6
72 (4-NO 2-C 6H 4SO 2) 2NH 8.32
73 1-C 10 H 7 SO 3 H 8.02
74 C 6H 5CHTf 2 7.85
75 4-Cl-C 6 H 4 SO 3 H 7.3
76 3-NO 2-C 6H 4SO 3H 6.78
77 4-NO 2 -C 6 H 4 SO 3 H 6.73
78 4-MeO-C 6 H 4 C(=NTf)NHTf 6.54
79 4-Me-C 6H 4C(=NTf)NHTf 6.32
80 TosNHTf 6.30
81 C 6 H 5 C(=NTf)NHTf 6.17
82 C 6 H 5 SO 2 NHTf 6.02
83 4-F-C 6 H 4 C(=NTf)NHTf 5.79
84 4-Cl-C 6 H 4 C(=NTf)NHTf 5.69
85 2,4,6-(SO 2 F) 3 -Phenol 5.66
86 4-Cl-C 6 H 4 SO 2 NHTf 5.47
87 4-Cl-C 6H 4SO(=NTf)NHTos 5.27
88 4-NO 2-C 6H 4C(=NTf)NHTf 5.13
89 2,4,6-Tf 3-Phenol 4.93
90 4-NO 2 -C 6 H 4 SO 2 NHTf 4.52
91 4-Cl-C 6H 4SO(=NTf)NHSO 2C 6H 4-4-Cl 4.47
92 2,3,5-tricyanocyclopentadiene 4.16
93 4-Cl-C 6H 4SO(=NTf)NHSO 2C 6H 4-4-NO 2 3.75
1.06 0.73
1.05 0.46
0.53
0.23
2.3
0.56 1.73
1.21 0.23
0.19 1.04
0.54
0.53
0.51
0.51
0.44 1.28
0.75
0.36
0.77
0.53
0.38
0.41
1.25
1.3
0.25
0.50
0.59
0.26
0.83
1.64
0.64
0.71
0.05
0.87
1.10 1.15
0.31
0.74
0.50
0.23
0.23
0.05
0.62
0.5
0.16 0.35
1.11 0.47
1.37
1.25
0.42
0.59
1.20
1.1
H 2 SO 4 pK a ca 8
19
1,2-Dichloroethane
• Advantages of 1,2-DCE:
• Very low basicity (B' = 40), low anion-solvating ability
→ strong superacids are measurable
• pK auto
unmeasurably high
• Reasonably inert and stable, readily available, widely
used, dissolves also many ionic compounds well
• Transparent in UV down to 230 nm
• Limitations:
• ~Low polarity (ε = 10)
• Ion-pair acidities
20
10

1,2-DCE acidity
scale
• The most acidic
equilibrium acidity
scale in a constantcomposition
medium
• Relative acidities
• Not easy to anchor
• Some values
available in
literature, but
are doubtful
A. Kütt et al J. Org. Chem.
2011, 76, 391
No Acid pK a(DCE) Directly measured ΔpK ip values in DCE a pK
1 Picric acid 0.0
2 HCl -0.4 0.73 0.71
1.48 0.36
3 2,3,4,6-(CF 3) 5-C 6H-CH(CN) 2 -0.7
1.09
0.77 0.74
4 4-NO 2-C 6H 4SO 2NHTos c -1.5
2.08 1.00
0.28 1.78
5 HNO 3 -1.7
1.01
6 4-NO 2-C 6H 4SO 2NHSO 2C 6H 4-4-Cl -2.4 1.13
0.88 0.08
7 H 2SO 4 -2.5
0.24
0.12 1.26
8 C 6(CF 3) 5CH(CN) 2 -2.6
1.02 1.02 1.05
9 (4-NO 2-C 6H 4-SO 2) 2NH -3.7 1.48
0.47
10 3-NO 2-4-Cl-C 6H 3SO 2NHSO 2C 6H 4-4-NO 2 -4.1
0.80
0.36
11 (3-NO 2-4-Cl-C 6H 3SO 2) 2NH -4.5 1.35
0.93
0.39
12 HBr -4.9
0.62
0.19
13 4-NO 2-C 6H 4SO 2CH(CN) 2 -5.1 1.03
0.80
14 2,4,6-(SO 2F) 3-Phenol -5.9 1.33
15 2,4,6-Tf 3-Phenol d -6.4 0.64
16 CH(CN) 3 -6.5 0.94
0.42 1.14 1.12
17 4-Cl-C 6H 4SO(=NTf)NHTos -6.8 0.33 0.65
0.51 0.05
18 NH 2-TCNP e -6.8
0.24
0.20
19 2,3,5-tricyanocyclopentadiene -7.0
20 Pentacyanophenol -7.6 0.67 0.84
21 4-Cl-C 6H 4SO(=NTf)NHSO 2C 6H 4-4-Cl -7.6 1.77
1.56
22 HI -7.7
1.64
1.00
0.98 1.13
23 4-NO 2-C 6H 4SO 2NHTf -7.8 1.10 0.93
1.04 1.01
0.81
24 Me-TCNP -8.6
0.96
0.90
0.09
25 3,4-(MeO) 2-C 6H 3-TCNP -8.7 0.13 1.42
-0.02
26 4-MeO-C 6H 4-TCNP -8.7
0.12
0.12
27 C(CN) 2=C(CN)OH -8.8
0.46 0.24
0.28 1.61
28 4-Cl-C 6H 4SO(=NTf)NHSO 2C 6H 4-NO 2 -8.9 0.22
0.59
0.74
29 2,4-(NO 2) 2-C 6H 3SO 2OH -8.9 0.67
0.06
0.59
30 C 6F 5CH(Tf) 2 -9.0
0.60
0.52
31 HB(CN)(CF 3) 3 -9.3 0.47 0.44
1.33 0.13
32 Ph-TCNP -9.4 1.56 1.62
0.83 1.57
33 HBF 4 -10.3
1.23
1.06
34 FSO 2OH -10.5 0.26 1.34
001
21
1,2-DCE acidity
scale
2,4-(NO 2) 2-C 6H 3SO 2OH
H N
45 [C(CN) 2=C(CN)] 2NH -11.8
46 3,5-(CF 3) 5-C 6H 3-TCNP -11.8
29 -8.9
30 C 6F 5CH(Tf) 2 -9.0
31 HB(CN)(CF 3) 3 -9.3
32 Ph-TCNP -9.4
33 HBF 4 -10.3
34 FSO 2OH -10.5
35 3-CF 3-C 6H 4-TCNP -10.5
36 H-TCNP -10.7
37 [C 6H 5SO(=NTf)] 2NH -11.1
38 [(C 2F 5)2PO] 2NH -11.3
39 2,4,6-(NO 2) 3-C 6H 2SO 2OH -11.3
40 [C(CN) 2=C(CN)] 2CH 2 -11.4
41 TfOH -11.4
42 C 6H 5SO(=NTf)NHTf -11.5
43 TfCH(CN) 2 -11.6
44 Br-TCNP -11.8
+
N P N
48 4-Cl-C 6H 4SO(=NTf)NHTf -12.1
47 Tf 2NH -11.9
N
49 Cl-TCNP -12.1
• Ion pair acidities
• Counter-ion:
• Aqueous pK a
(H 0
)
values down to
-10 .. -15
50 (C 3F 7SO 2) 2NH -12.2
51 (C 4F 9SO 2) 2NH -12.2
52 CN-CH 2-TCNP -12.3
53 (C 2F 5SO 2) 2NH -12.3
54 CF 3-TCNP -12.7
55 HClO 4 -13.0
56 CF 2(CF 2SO 2) 2NH -13.1
57 4-NO 2-C 6H 4SO(=NTf)NHTf -13.1
58 HB(CN) 4 -13.3
59 (FSO 2) 3CH -13.6
60 Tf 2CH(CN) -14.9
61 2,3,4,5-tetracyanocyclopentadiene -15.1
62 CN-TCNP -15.3
63 Tf 3CH f -16.4
64 CF 3SO(=NTf)NHTf f -18
0.67 0.06
0.59
0.60
0.52
0.47 0.44
1.33 0.13
1.56 1.62
0.83 1.57
1.23
1.06
0.26 1.34
0.01
0.21
0.60 0.22
0.58
0.73 0.78 0.46
0.84
0.84
0.89 0.91
0.29
0.28
0.44 0.21
0.10
0.12
0.47
0.04
0.07 0.09 0.49
0.40 0.32 0.47
0.36
0.21 0.45
0.19
0.30 0.31
1.06
0.06
0.69
0.20 0.25
0.01
0.10
0.10
0.19
0.15
0.13
0.27
0.10
0.02
1.05 1.06
0.72
0.19
0.19
0.44
1.76
1.92
2.16
1.46
1.73 0.22
0.40
0.21 0.23
0.36
0.47
0.67
0.40
0.21
0.44
0.46
0.80
0.80 1.04
0.40
0.11
0.56
0.89 0.86
1.29
0.63
1.04
0.07
0.42
0.77
0.73 0.75
0.93
0.93
0.96
0.43
22
0.29
11

Important aspects for superacids
• Brønsted acidity
• As strong as possible
• "Clean" protonation desirable
• Lewis acidity is usually not desirable
• Stability under superacidic conditions
• Weak coordinating properties of the
anions
23
Design of superacidic molecules
• "Acid-based" approach:
• Pick a parent acid
• Introduce substituents
• electronegative, strong electron
acceptors, highly polarizable
CN CN
O O
H
NC P CN
NC
O CN ΔΔG acid =
47 kcal/mol
ΔG acid = 303 256 kcal/mol
(DFT B3LYP/6-311+G**)
O CF 3
S O
ON
F 3 C
S
OH
ON
S O
ΔΔG acid =
O CF 3 40 kcal/mol
ΔG acid = 299.5 260 kcal/mol
(DFT B3LYP/6-311+G**)
Leito et al J. Mol. Stru.
Theochem, 2007, 815, 43
Koppel, Yagupolskii et al
to be submitted
24
12

Basicity Centers on Substituents
NC
:
CN
NC
:
P
CN
H
CN:
N H
. .
CN
:
: :
. .
:
O
CF 3
H
S
:
N
. O
.:
. .
F 3 C
S . OHO
.
:
N
. .
S
O
:
:
CF . O
.
3
It is not only about the acceptor
power but also about basicity!
25
Design: Anion-based approach
• Design an anion, which
• Has delocalized charge
• Is as stable as possible
• Has as few as possible protonation sites and
those are of low basicity
Not looking at any particular acidity
center
26
13

Fluorine
• Highly electronegative element
• Decreases the basicity of nearby basicity centers
• Has very low basicity itself
• Many X-F bonds are extremely strong
• C-F bond: 484 kJ/mol
• High stability of fluorinated compounds
• Small size
• Polyfluorinated compounds have low steric strain
Fluorination is intrinsically suitable
for superacid design
27
Substituent properties
Substituent
σ F
σ R σ α
0.13
-F
0.57
-0.33
-CF 3
0.46
0.09
-0.25
-SO 2 CF 3
0.18
0.83
0.26
-0.58
-CN
0.54
-0.46
• Neither –F nor –CF 3 seem particularly
impressive
28
14

-F and -CF 3 vs -CN
Acid
X OH
(DFT B3LYP/6-311+G**)
Gas-phase acidity (kcal/mol)
-CN -F -CF 3
325 340 330
X
X
X
-
B X H +
250
277
X
X
259
290
244
X
HBX 4
213
X
X
C X
X
-
X
X
X X X
X H +
X
225

250
256
255.5 HSbF 6
250.8 HAuF 6
250
243
240
HB(CF3 ) 4
NC
NC
H
NC CN
C
H
H
H
H H
Cl
Cl
Cl
CN CN
- H +
CN NC P CN
- B CN H + NC CN
-
Cl
Cl
H +
Cl
Cl Cl
Acidity in the
gas phase
Cl
CCl
Cl
Cl
225
200
225
213
C CN
NC CN
NC CN
-
F NC NC CN CN
NC
C
F
F
H +
F CN
F F
F
F
< 175
F
-
F
CN
F F CF
H +
3
C
F 3 C
CF 3
CF F3 C CF 3 3
-
F
F 3 C 3 C CF 3 CF 3
F 3 C H +
CF 3
Cl
Cl
Cl
Cl
Cl
H +
Cl
GA = 241 ± 29 kcal/mol
- Meyer et al, JACS, 2009, 131, 18050
-Kütt et alChem Phys Chem,
2008
- Kütt et al, JOC, 2008, 73, 2607
- Leito et al, J Mol Stru Theochem.
2007, 815, 41
- Leito et al, JPC A, 2009, 113, 8421
- Koppel et al, JACS, 2000,
31
122, 5114
Thanks
to all these
people!
32
16

Collaboration
• Y.L. Yagupolskii
(IOC, Ukrainian Academy of Sciences, Kiev)
• I. Krossing, D. Himmel
(Freiburg University)
• A.A. Kolomeitsev, G.-V. Röschenthaler
(IIPC, University of Bremen)
• M. Rueping (Aachen University)
• V.M. Vlasov (IOC, Russian Academy o Sciences,
Novosibirsk)
• M. Mishima (IMCE, Kyushu University)
33
Overview:
http://tera.chem.ut.ee/~ivo/HA_UT/
34
17