Perfluorinated 1,2,3- and 1,2,4-Triazolium Ionic Liquids

Article abstract of DOI:10.1002/ejoc.201800582

Dialkyl triazolium triflimides with perfluorinated side chains were prepared as hydrophobic ionic liquids (ILs) for surface impregnation. The key feature of the new materials are relatively short perfluorohexyl residues (nC₆F₁₃ = R_F) as the fluorinated part of the cations, making the target compounds beneficial alternatives to established products because of their enhanced degradability and therefore lower bioaccumulativity. As heterocyclic scaffold, either 1,2,3-triazole or 1,2,4-triazole were chosen. As the two alkyl moieties, either two R_FCH₂CH₂ groups or one R_FCH₂CH₂ and one Et residue were applied. The diethyl congeners were also prepared. Fluorinated starting materials were R_FCH₂CH₂OTf as alkylating reagent or R_FCH₂CH₂N₃ as 1,3-dipole for a copper catalyzed cycloaddition (CuAAC) with trimethylsilyl acetylene. After sequential CuAAC and alkylation reactions, the triflimide salts were finally obtained from the intermediate iodides or triflates with the aid of an ion exchange resin. Out of 14 triazolium salts prepared, four compounds have finally been identified as hydrophobic ILs (contact angles between 85° and 100° with mp. < 100 °C), being promising materials for surface impregnation: the 1,2,3-triazolium triflate and triflimide with two fluorinated alkyl residues, and the 1,2,4-triazolium triflimides (two regioisomers) with one fluorinated alkyl residues and one ethyl group.

Full text of DOI:10.1002/ejoc.201800582

A Journal of
Accepted Article
Title: Perfluorinated 1,2,3- and 1,2,4-Triazolium Ionic Liquids
Authors: Torben Alpers, Thomas Muesmann, Oliver Temme, and Jens
Christoffers
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European Journal of Organic Chemistry
10.1002/ejoc.201800582
Perfluorinated 1,2,3- and 1,2,4-Triazolium Ionic Liquids
[
a,b]
[b]
[b]
[a]
Torben Alpers,
Thomas W. T. Muesmann, Oliver Temme, Jens Christoffers*
[
a] M.Sc. T. Alpers, Prof. Dr. J. Christoffers, Institut für Chemie, Carl von Ossietzky
Universität Oldenburg, 26111 Oldenburg, Germany. Fax: +49(0)441 798 3873. Email:
jens.christoffers@uol.de. Homepage: www.christoffers.chemie.uni-oldenburg.de
[
b] M.Sc. T. Alpers, Dr. T. Muesmann, Dr. O. Temme, Ferdinand Eimermacher
GmbH & Co. KG, Westring 24, 48356 Nordwalde, Germany.
Graphical Abstract
Key topic: Fluorinated Ionic Liquids
N
F C
N
N
C F
F C
N
N
C F
6 13
1
3 6
6 13
13
6
N
Y
Y
Y = I, OTf, NTf2
Dialkyl 1,2,3- and 1,2,4-triazolium triflimides with perfluorinated side chains were
prepared by copper-catalyzed alkyne azide cycloaddition or alkylation reactions. The
products shall serve as hydrophobic ionic liquids for surface impregnation.
Abstract. Dialkyl triazolium triflimides with perfluorinated side chains were prepared
as hydrophibic ionic liquids (ILs) for surface impregnation. The key feature of the new
materials are relatively short perfluorohexyl residues (nC F = R ) as the fluorinated
6
13
F
part of the cations, making the target compounds beneficial alternatives to
established products because of their enhanced degradability and therefore lower
bioaccumulativity. As heterocyclic scaffold, either 1,2,3-triazole or 1,2,4-triazole were
chosen. As the two alkyl moieties, either two R CH CH groups or one R CH CH
2
F
2
2
F
2
and one Et residue were applied. The diethyl congeners were also prepared.
Fluorinated starting materials were R CH CH OTf as alkylating reagent or
F
2
2
R CH CH N as 1,3-dipole for a copper catalyzed cycloaddition (CuAAC) with
F
2
2 3
trimethylsilyl acetylene. After sequential CuAAC and alkylation reactions, the triflimide
salts were finally obtained from the intermediate iodides or triflates with the aid of an
ion exchange resin. Out of 14 triazolium salts prepared, four compounds have finally
been identified as hydrophobic ILs (contact angles between 85° and 100° with mp. <
100°C), being promising materials for surface impregnation: the 1,2,3-triazolium
1
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European Journal of Organic Chemistry
10.1002/ejoc.201800582
triflate and triflimide with two fluorinated alkyl residues, and the 1,2,4-triazolium
triflimides (two regioisomers) with one fluorinated alkyl residues and one ethyl group.
Keywords: Ionic Liquids; Fluorine compounds; Heterocyclic Compounds; Triazoles,
Click Chemistry; Triflimide
Introduction
[
1]
Ionic liquids (ILs) represent a prominent class of organic materials. Due to their
wide temperature range of the liquid state, associated with a low vapor pressure, high
[
2]
thermal stability and good recyclability, ILs are often associated with sustainable
[
3]
processes and green chemistry, although their benefits are sometimes critically dis-
[
4]
cussed. With respect to the cations, this compound class is dominated by imidazo-
[
5]
lium, phosphonium, pyridinium and quaternary ammonium salts. 1,2,3- and 1,2,4-
[
6]
triazolium based ILs, however, are reported more rarely. As the prototypic repre-
[
7]
sentative of "click chemistry", the copper-catalyzed Huisgen 1,3-dipolar cycload-
[
8]
dition of an alkyne with an organic azide (CuAAC) developed very rapidly during the
past two decades. For this reason, 1,2,3-triazoles became one of the most popular
[
9]
[10]
classes of heterocyclic compounds in Life Sciences as well as Materials Science.
In contrast to the paramount prominence of 1,2,3-triazoles, the constitutionally isome-
ric 1,2,4-triazole motif is, of course, far less represented in the literature, although
many biologically relevant compounds carry this heterocycle. Most of them show
significant antifungal activity and are applied as active pharmaceutical ingredients for
[
11]
[12]
human therapy or for agricultural antifungal treatments.
Perfluorinated carboxylic and sulfonic acids (CnF2n+1CO H and C F SO H with n >
2
n
2n+1
3
6) are ubiquitously applied for surface impregnation of paper, cardboard, textiles, lea-
[
13]
thers, polymeric materials, metals etc. Especially so called fluorocarbon resins are
[
14]
widely used as materials for industrial as well as consumer applications, firefighting
[
15]
foams, aviation hydraulic fluids, pesticides and paints.
The most prominent repre-
sentatives of this compound class are PFOA (C F CO H) and PFOS
7
15
2
[
16]
(
C F SO H).
Although PFOA and PFOS itself are quite harmless since chemically
8
17
3
inert, they are for the same reason persistent and came into the focus of environmen-
tal concerns. In particular, they are accumulated in the biosphere and are not affect-
[
17]
ted by biodegradation or photodegradation. Meanwhile, they are detectable ubiqui-
2
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European Journal of Organic Chemistry
10.1002/ejoc.201800582
[
18]
[19]
tously in the abiotic environment
as well as in animals and humans
and have
thus attracted attention as global contaminants. Especially PFOA, because of its wa-
ter solubility, was found in animal serum as well as in fat and it was shown that PFOA
[
20]
could bind to proteins.
These compounds were consequently listed under Annex B
[
21]
(
restriction of production and use) of the Stockholm Convention in 2009.
Further-
more, the European Chemicals Agency lists PFOA on the SVHC Candidate List as a
CMR-substance (SVHC = substance of very high concern; CMR = carcinogenic,
[
22]
mutagenic, or toxic for reproduction).
The chemical industry currently makes efforts
[
23]
for identifying replacements for perfluoroalkyl materials with C F chains or higher.
8
17
A reasonable alternative are shorter chain compounds with C F or C F residues,
6
13
4 9
which on the one hand could address the same outstanding material properties, but
on the other hand do not accumulate in the environment due to their increased de-
gradability.
As a manufacturer of water repellent textile coatings, we are aiming at identifying new
compounds, which can be used as replacements for commonly used long chained
[
24]
perfluorinated substances.
Our idea was to develop fluorinated ILs, which has
[
25]
been realized in a few cases before. Most of the literature reports utilize perfluoro-
[
26]
[27]
carboxylic acids as anions,
but also perfluorinated cations have been published.
[
28]
[29]
Among the perfluorinated cations, imidazolium,
quaternary ammonium
and qua-
[
30]
ternary phosphonium species
have been reported. Fluorinated 1,2,3- and 1,2,4-tri-
azolium salts were rarely reported so far; all of them carry only one perfluorinated
[
31]
side chain.
Fluorinated 1,2,3-triazolium cations without substituents in the 4- and 5-
position are completely unknown. Herein we wish to disclose the synthesis of a small
series of fluorinated ILs based on 1,2,3- and 1,2,4-triazoles with double (products 1
and 4) or single (products 2, 5, 6) perfluoroalkylation at nitrogen and no substituents
at the carbon atoms (Figure 1). As fluorinated side chains R , perfluorohexyl residues
F
were applied. Furthermore, we have prepared the triazoles 3 and 7 with two ethyl
–
residues as reference materials. As anions Y, iodide or triflate (OTf ) originated from
–
2
the synthesis of intermediate products, but were both exchanged by triflimide [NTf ,
bis(trifluoromethylsulfonyl)imide anion].
3
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European Journal of Organic Chemistry
10.1002/ejoc.201800582
R1
N
R2
R1
R2
N
N
N
N
Y
Y
N
1
2
1
2
1
2
3
, R , R = (CH ) R ,
4, R , R = (CH ) R ,
2
2
F
2 2 F
1
2
1
2
, R = Et, R = (CH ) R ,
5, R = Et, R = (CH ) R ,
2
2
F
2 2
2
F
1
2
1
, R , R = Et,
6, R = (CH ) R , R = Et,
2
2 F
1
2
7
, R , R = Et,
Y = I, OTf, NTf2,
R = nC F
F
6 13
Figure 1. Target compounds of this study.
Results and Discussion
1,2,3-Triazolium Salts. For the preparation of 1-alkyl 1,2,3-triazoles 9 and 11 we en-
visioned the CuAAC of TMS-acetylene with alkyl azides which subsequent protode-
silylation of the TMS-group with fluoride, as was reported before by Ryu and cowor-
[
6a]
ker.
For this purpose, we first prepared perfluorinated azide 8 from the respective
[
31c]
iodide R CH CH I following the procedure of Read et al.
Conversion of azide 8
F
2
2
with TMSC≡CH in the presence of CuSO and sodium ascorbate was directly
4
followed by treatment of the reaction mixture with TBAF (Scheme 1). Compound 9
[32]
was obtained in 71% yield after chromatography. Initial attempts of alkylation 1,2,3-
triazole (10) with R CH CH I failed, whereas the use of R CH CH OTf (prepared
F
2
2
F
2
2
from the respective alcohol R CH CH OH ("6:2 FTOH") according to a literature
F
2
2
[
33]
procedure)
reaction is in this case the method of choice. The next steps towards triazolium salts
a and 2a were alkylations of compound 9 with R CH CH OTf or EtI, which were
as alkylating reagent gave compound 9 in 10% yield. Thus, the CuAAC
1
F
2
2
performed in acetone at 130°C in a sealed reaction vial. The bis(perfluoroalkyl)
triflate 1a was obtained in 66% yield, the mono(perfluoroalkyl) congener 2a was
obtained as the iodide in almost quantitative yield, both after recrystallization from
MTBE.
4
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European Journal of Organic Chemistry
10.1002/ejoc.201800582
RF
RF
RF
RF
(a)
(b)
(
N
N
N
N
N
N
N3
Y
8
9, 71%
1a, Y = OTf, 66%
c)
1
b, Y = NTf , 96%
2
RF
RF
(
d)
(
N
N
Et
N
N
N
N
N
Y
9
2a, Y = I, 99%
c)
c)
2
b, Y = NTf , 91%
2
(
e)
(f)
N
N
N
Et
Et
Et
N
NH
N
N
N
Y
1
0
11, 68%
3a, Y = I, 99%
(
3
b, Y = NTf , 98%
2
Scheme 1. Preparation of 1,2,3-triazolium salts 1a,b–3a,b; reagents and conditions:
a) 1. 0.02 equiv. CuSO , 0.2 equiv. sodium ascorbate, 1.5 equiv. TMSC≡CH, THF,
(
4
2
3°C, 16 h; 2. 3.0 equiv. TBAF, THF, 23°C, 6 h; (b) 2.0 equiv. R CH CH OTf,
F 2 2
acetone, 130°C, 3 h; (c) 1. column of hydroxide loaded Lewatit Mono MP Plus 800, 2.
1
.0 equiv. HNTf ; (d) 4.0 equiv. EtI, acetone, 130°C, 3 h; (e) 2.0 equiv. EtI, 1.0 equiv.
2
1
0, 2.0 equiv. K CO , THF, 23°C, 25 h; (f) 2.0 equiv. EtI, acetone, 130°C, 3 h.
2
3
The diethyl-substituted compound 3a was prepared as reference material. In a first
approach, compound 11 was prepared by CuAAC from NaN , EtI and TMS-acety-
3
lene. However, the overall yield after cleavage of the TMS group remained low
(
26%). Therefore, the alkylation of 1,2,3-triazole (10) with EtI was chosen to access
compound 11, which was obtained in 68% after distillation. Interestingly, no compe-
ting alkylation at the 2-position of the triazole 10 was found, as was reported in the
[
34]
literature by others. Alkylation of triazole 11 with EtI proceeded straightforwardly in
acetone at 130°C to give iodide salt 3a in quantitative yield after recrystallization from
MTBE.
Finally, the triflate (from 1a) and iodide ions (from 2a and 3a) were changed to triflimi-
–
2
de (NTf ). First, the triazolium hydroxides were obtained from a column of hydroxide
loaded anion exchange resin, which were then neutralized with the acid HNTf . After
2
evaporation and recrystallization from MTBE, the yields of the triflimide salts 1a–3a
were very good (91–98%); their purity was confirmed by elemental combustion ana-
5
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European Journal of Organic Chemistry
10.1002/ejoc.201800582
lysis. The anion exchange did not lead to differences of the NMR spectra of the
cations.
1,2,4-Triazolium salts. The twofold perfluoroalkylated 1,2,4-triazolium salt 4a was
obtained in two steps from the parent heterocycle 12. The first alkylation with
R CH CH OTf was achieved at ambient temperature and proceeded regioselectively
F
2
2
at the 1-position, which is clearly indicated by the NMR-spectra of this unsymmetric
compound 13. The second alkylation required, as in the 1,2,3-triazole series, eleva-
ted temperature (130°C in acetone) and led to bis(perfluoroalkyl) triflate 4a in 83%
yield after recrystallization from MTBE. The mixed ethyl-perfluoroalkyl compound 5a
was respectively accessed from compound 13 with EtI. The iodide salt 5a was
obtained in 91% yield after recrystallization from MTBE. Although the 1,4-dialkyl con-
stitution of compound 5a is already determined by the constitution of the starting ma-
1
terial, it was double checked by 2D NMR experiments. In particular, the methylene H
3
resonance of the ethyl group at N-4 (q at 4.32 ppm) shows HMBC J-crosspeaks to
13
both aromatic C CH resonances (C-5 at 143.15 ppm and C-3 at 144.15 ppm),
whereas the α-CH moiety of the fluorinated residue (t at 4.78 ppm) shows a HMBC
2
3
–
J-crosspeak to only one aromatic CH (C-5 at 143.15 ppm). The exchange of OTf
–
(
from 4a) and I (from 5a) proceeded as in the 1,2,3-triazolium series via the hydro-
xide salts. The triflimides 4a (88%) and 5b (99%) were obtained after recrystallzation
from MTBE; their purity was confirmed by elemental combustion analysis. Again,
NMR spectra of the cations remain the same.
RF
RF
RF
(
a)
(b)
N
NH
N
N
N
N
Y
N
N
N
1
2
13, 53%
4a, Y = OTf, 83%
(
c)
c)
4
b, Y = NTf , 88%
2
RF
RF
(
d)
Et
N
N
N
N
N
Y
N
1
3
5a, Y = I, 91%
(
5
b, Y = NTf , 99%
2
Scheme 2. Preparation of 1,2,4-triazolium salts 4a,b and 5a,b; reagents and con-
ditions: (a) 2.0 equiv. R CH CH OTf, 2.0 equiv. K CO , acetone, 23°C, 24 h; (b) 2.0
F
2
2
2
3
equiv. R CH CH OTf, acetone, 130°C, 3 h; (c) 1. column of hydroxide loaded Lewatit
F
2
2
Mono MP Plus 800, 2. 1.0 equiv. HNTf ; (d) 2.0 equiv. EtI, acetone, 130°C, 3 h.
2
6
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European Journal of Organic Chemistry
10.1002/ejoc.201800582
The mono-perfluoroalkyl 1,2,4-triazolium salt 6a regioisomeric to compound 4a was
obtained by double alkylation with inverted use of the electrophiles. First, 1,2,4-tri-
azole (12) was alkylated with EtI at ambient temperature furnishing compound 14
(
60%), which is again exclusively formed as the 1-regioisomer. This compound was
[
35]
reported before (39% yield).
The perfluoroalkyl residue was then introduced at
130°C in acetone; compound 6a was obtained in 90% yield after recrystallization
from MTBE. As for compound 5a, the constitution of compound 6a as double
checked by a HMBC experiment: The ethyl CH resonance (q at 4.42 ppm) shows
2
3
only one J-crosspeak to C-5 at 142.65 ppm, whereas the α-CH resonance of the
2
3
fluorinated residue (t at 4.64 ppm) shows J-crosspeaks to both aromatic CH signals
(
C-5 at 142.65 ppm and C-3 at 144.91 ppm). Again, as a reference compound, the
[
36]
diethyl congener 7a was prepared, which actually literature known.
In both cases,
–
–
–
2
the OTf and I were exchange to NTf via the hydroxides as reported above.
Compounds 6b (95%) and 7b (83%) were obtained after recrystallization from MTBE;
their purity was confirmed by elemental combustion analysis. Also in these cases, the
NMR spectra of the cations did not change.
RF
(
a)
(b)
(
Et
Et
N
NH
N
N
N
N
Y
N
2
N
N
1
14, 60%
6a, Y = OTf, 80%
c)
c)
6
b, Y = NTf , 95%
2
(d)
Et
Et
Et
N
N
N
4
N
N
Y
N
1
7a, Y = I, 98%
(
7
b, Y = NTf , 83%
2
Scheme 3. Preparation of 1,2,4-triazolium salts 6a,b and 7a,b; reagents and condi-
tions: (a) 2.0 equiv. EtI, 2.0 equiv. K CO , acetone, 23°C, 21 h; (b) 2.0 equiv.
2
3
R CH CH OTf, acetone, 130°C, 3 h; (c) 1. column of hydroxide loaded Lewatit Mono
F
2
2
MP Plus 800, 2. 1.0 equiv. HNTf ; (d) 2.0 equiv. EtI, acetone, 130°C, 3 h.
2
Physical properties. All triazolium salts carrying at least one fluorinated residue,
1a,b–2a,b and 4a,b–6a,b, are unsoluble in water and hexanes, but sparely soluble in
MTBE, CH Cl and CHCl at ambient temperature. They show solubility in MeOH,
2
2
3
DMSO or acetone, which is sufficient to obtain NMR-spectra in these solvents. The
7
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European Journal of Organic Chemistry
10.1002/ejoc.201800582
diethyl congeners 3a,b and 7a,b are well soluble in water, CH Cl , CHCl , MeOH and
2
2
3
acetone and poorly in hexanes and MTBE.
Some of the compounds (1a,b–7a,b) are solids and their melting points are listed in
Table 1. It is noticable that all triflimides can be regarded as ILs, with low melting
points up to 51°C (for 6b). All other triflimide salts melt at lower temperatures and
some of them (2b, 3b, 4a, 7b) could be even regarded as RTILs (room temperature
ILs). The triflates or iodides 1a–7a generally show a higher melting point compared to
their respective triflimides 1b–7b. Only compounds 1a, 3a, and 7a could be regarded
as IL by definition. Compound 3a is a RTIL. Regarding the differences between the
isosteric 1,2,3- and 1,2,4-triazolium series, it is interesting to observe a high melting
point difference of about 100 K between compounds 1a (99°C) and 4a (196°C). A si-
milar phenomenon is observed for compounds 3a (liquid) and 7a (84°C). The diffe-
rence could be explained by lack of symmetry for the 1,2,4-trizaolium motif leading to
a higher dipole moment, thus, better crystallinity compared to their 1,2,3-isosters.
In order to obtain a first impression of water repellency of the new compounds, we
have investigated the wettability of a thin film spread on a glass surface by measuring
[
30]
the water contact angle. This investigation was actually only possible for solid com-
pounds. They were spread by melting them on a hot glass plate. Table 1 lists the
average of left and right angle. All compounds are far from being "super-
hydrophobic". Water soluble compound 7a could actually being regarded as
hydrophilic (contact angle 26.4°). Reasonable hydrophobicity was observed for
compound 4a (113.1°), which is actually no IL, and compounds 1b (97.1°) and 6b
(
100.2°).
8
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European Journal of Organic Chemistry
10.1002/ejoc.201800582
Table 1. Selected properties of products 1a,b–7a,b: Melting points and water contact
angles (the average value between left and right angle together with its span width is
given).
1
2
Compound
R
R
Y
mp.
Contact angle
1
2
3
4
5
6
a
a
a
a
a
a
(CH ) R
(CH ) R
F
OTf
99°C
85.31.5°
46.90.0°
–
2
2
F
2 2
(CH ) R
F
Et
Et
I
148°C
liquid
2
2
Et
(CH ) R
I
(CH ) R
F
OTf
I
196°C
208°C
152°C
113.10.0°
64.10.6°
65.12.5°
2
2
F
2 2
Et
(CH ) R
F
(CH ) R
F
2
2
Et
Et
OTf
2
2
7a
1b
2b
3b
4b
5b
Et
(CH ) R
I
84°C
41°C
liquid
liquid
liquid
50°C
26.40.1°
(CH ) R
F
NTf2
NTf2
NTf2
NTf2
NTf2
97.10.1°
2
2
F
2 2
(CH ) R
F
Et
Et
–
2
2
Et
(CH ) R
–
(CH ) R
F
–
2
2
F
2 2
Et
(CH ) R
F
(CH ) R
F
89.01.2°
2
2
6
b
b
Et
Et
NTf2
NTf2
51°C
liquid
100.20.1°
2
2
7
Et
–
Summary. In the course of efforts to replace PFOA (C F CO H) and PFOS
7
15
2
(
C F SO H) as surface active materials many industrial manufacturers started off in-
8 17 3
vestigations on alternative resins with shorter perfluorinated alkyl chains, to achieve
enhanced biodegradability and therefore lower bioaccumulativity. Our contribution to
this field is the development of novel ionic liquids with triazolium cations carrying per-
fluorinated hexyl residues (nC F , "R "), which were introduced by R CH CH OTf as
6
13
F
F
2
2
alkylating reagent or R CH CH N as 1,3-dipole in a cycloaddition reaction.
F
2
2
3
In particular, we have prepared 1,3-dialkylated 1,2,3-triazolium and 1,4-dialkylated
,2,4-triazolium triflimides, with either two perfluorinated residues or one
1
perfluoroalkyl and ethyl residue.
In the 1,2,3-triazolium series, perfluorinated triazole 9 was obtained by CuAAC of
TMS-acetylene with R CH CH N 8 (71% yield). This intermediate product 9 was
F
2
2 3
alkylated by R CH CH OTf or EtI to give triflate 1a (66%) and iodide 2a (99%).
F
2
2
Furthermore, the diethyl triazolium iodide 3a (99%) was prepared. The anions of all
9
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European Journal of Organic Chemistry
10.1002/ejoc.201800582
three compounds 1a, 2a, and 3a were changed with the aid of an ion exchange resin
to the hydroxide, and these products were then neutralized with Tf NH to furnish the
2
respective triflimide salts 1b (96%), 2b (91%), and 3b (98%).
In the second series, 1,2,4-triazole was alkylated regioselectively in the 1-position
with either R CH CH OTf or EtI to give two intermediate products 13 (53%) and 14
F
2
2
(
60%), which were both submitted to a second alkylation with again R CH CH OTf or
F 2 2
EtI. Thus, four 1,2,4-triazolium salts with either triflate or iodide anion, 4a (83%), 5a
91%), 6a (80%), and 7a (98%) were obtained. As above, the anions of all four com-
pounds 4a–7a were changed to the respective triflimide salts 4b (88%), 5b (99%), 6b
95%), and 7b (83%).
The melting points of triflates and iodides 1a–7a are higher (some even above
00°C) than their respective triflimide congeners 1b–7b. The latter can all be re-
(
(
1
garded as ILs (mp. < 100°C), some are even RTILs. The water contact angles were
investigated. Four materials (compounds 1a, 1b, 5b, and 6b) were identified as
hydrophobic ILs (contact angles >90° with mp. <100°C), being promising materials
for surface impregnation.
Experimental Section
General: Preparative column chromatography was carried out using Merck SiO (35–
2
70 μm, type 60 A) with hexanes (bp 40–60°C) and tert-butyl methyl ether (MTBE) as
1
19
eluents. TLC was performed on aluminum plates coated with SiO F . H-, F- and
2
254
13
C-NMR spectra were recorded on Bruker Avance 500 MHz and 300 MHz instru-
13
ments. Multiplicities of carbon signals were determined with DEPT experiments. C-
signals of CF and CF moieties (including OTf and NTf ) could not be individually
2
3
2
distinguished due to extended overlapping. MS and HRMS spectra of products were
obtained with an Thermo Fischer DFS (EI) or a Waters Q-TOF Premier (ESI, positive
mode) spectrometer. IR spectra were recorded on a Bruker Tensor 27 spectrometer
equipped with a "GoldenGate" diamond ATR unit. Elemental analyses were
determined with a Euro EA-CHNS instrument from HEKAtech. Melting points were
obtained with a Gallenkamp device; values are uncorrected. Contact angle measure-
ments were performed with a Contact Angle System OCA, model 15plus from data-
physics and a Teli ccd camera, model CS8620C1. The droplet volume was 9 μL and
photograph was taken after 2 s. The perfluorinated starting materials
1
0
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European Journal of Organic Chemistry
10.1002/ejoc.201800582
[
3
31c]
[33]
R CH CH N
(8) and R CH CH OTf
were prepared according to literature
F
2
2
F
2
2
procedures. All other starting materials were commercially available. In particular,
nC F CH CH OH was purchased from DuPont.
6
13
2
2
General procedure: Exchange of anions with HNTf . A column of ion-exchange
2
resin Lewatit Mono MP Plus 800 (20 g, Lanxess, capacity ca. 0.95 mmol/g) was rege-
nerated prior to each use by the following sequential washings: (1) with hydrochloric
acid (10 mL, 2 mol/L) until to pH = 1 of the eluent, (2) with water until pH = 7, (3) with
aq. NaOH (10 mL, 2 mol/L) until pH = 13–14 and finally (4) again with water to pH =
7.
A solution of the triflate salts 1a, 4a, or 6a (0.33–0.84 mmol) or iodide salts 2a, 3a, 5a
or 7a (0.241–1.98 mmol) in 5 mL MeOH was applied to the column and the hydroxide
salts eluted with methanol, until pH = 7 of the eluent; the eluted volume was about
100–200 mL each time. The hydroxide salts were not isolated, but its solutions in
MeOH were treated with HNTf (1.0 equiv.), the resulting mixtures were evaporated
2
and the residues recrystallized from MTBE to furnish the triflimide salts 1b–7b.
1
-(1H,1H,2H,2H-Perfluorooctyl)-1,2,3-triazole (9). A solution of R CH CH N (8)
F 2 2 3
(
1.01 g, 2.60 mmol, 1.0 equiv.), sodium ascorbate (52 mg, 0.26 mmol, 0.1 equiv.),
–3
CuSO (0.026 mmol, 10 mL of a 2.6 ∙ 10 mol/L aqueous solution, 0.01 equiv.) and
4
TMSC≡CH (383 mg, 3.90 mmol, 1.5 equiv.) in THF (15 mL) was stirred for 7 h at
2
3°C. More sodium ascorbate (52 mg, 0.26 mmol, 0.1 equiv.) and CuSO (0.026
4
–3
mmol, 10 mL of a 2.6 ∙ 10 mol/L aqueous solution, 0.01 equiv.) was added and it
was stirred for additional 16 h at 23°C. TBAF (2.5 g, 7.8 mmol, 3.0 equiv.) was then
added to the reaction mixture and it was stirred for additional 6 h at 23°C.
Subsequently, MTBE (50 mL) was added and the solution was washed with water (3
x 20 mL). The organic layer was dried (MgSO ) and evaporated after filtration.
4
Product 9 (769 mg, 1.85 mmol, 71%) was obtained after chromatography (SiO2,
1
hexanes/MTBE 1:7, R = 0.13) as colorless solid, mp. 90°C. H-NMR (300 MHz,
f
CD OD): δ = 2.95 (tt, J = 7.2 Hz, J = 18.8 Hz, 2H), 4.82 (t, J = 7.0 Hz, 2H), 7.75 (s,
3
13
1
1
H), 8.09 (s, 1H) ppm. C{ H}-NMR (125 MHz, CD OD): δ = 32.29 (t, J = 21.7 Hz,
3
19
1
CH ), 43.28 (CH ), 126.32 (CH), 134.55 (CH) ppm. F{ H}-NMR (470 MHz, CD OD):
2
2
3
δ = –80.78 (tt, J = 2.4 Hz, J = 9.9 Hz), (–113.39)–(–113.60) (m), (–121.69)–(–121.93)
m), (–122.70)–(–122.90) (m), (–123.44)–(–123.61) (m), (–125.99)–(–126.18) (m)
(
1
1
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European Journal of Organic Chemistry
10.1002/ejoc.201800582
ppm. IR (ATR): nu(tilde) = 3099 (w), 1232 (s), 1186 (vs), 1140 (vs), 1124 (s), 1080
–1
(
s), 825 (s), 726 (s), 708 (s), 634 (s), 566 (s) cm . HRMS (EI, 70 eV): calcd.
+
+
4
15.0354 (for C H F N ), found 415.0356 [M ]. C H F N (415.05).
10 6 13 3 10 6 13 3
1,3-Bis(1H,1H,2H,2H-perfluorooctyl)-1,2,3-triazolium trifluoromethanesulfonate
(
1a). A solution of R CH CH OTf (1.91 g, 3.85 mmol, 2.0 equiv.) and triazole 9 (800
F 2 2
mg, 1.93 mmol, 1.0 equiv.) in acetone (2 mL) was stirred in a tightly closed reaction
tube for 3 h at 130°C. After evaporation of the volatiles, the residue was recrystallized
from MTBE (20 mL) to furnish product 1a (1.16 g, 1.28 mmol, 66%) as colorless
1
solid, mp. 99°C. H-NMR (300 MHz, DMSO-d ): δ = 2.99–3.26 (m, 4H), 5.09 (t, J =
6
13
1
6
.1 Hz, 4H), 9.06 (s, 2H) ppm. C{ H}-NMR (125 MHz, DMSO-d ): δ = 29.28 (t, J =
6
19
1
2
1.8 Hz, CH ), 45.92 (CH ), 131.82 (2 CH) ppm. F{ H}-NMR (470 MHz, DMSO-d ):
2
2
6
δ = –77.84 (s), –80.69 (tt, J = 10.3 Hz, J = 2.6 Hz), (–113.56)–(–113.81) (m), (–
1
1
2
21.91)–(–122.17) (m), (–122.87)–(–123.08) (m), (–123.26)–(–123.40) (m), (–
26.06)–(–126.26) (m) ppm. IR (ATR): nu(tilde) = 2354 (m), 2330 (m), 2195 (m),
–1
172 (m), 2067 (m), 1982 (m), 1141 (s), 640 (s), 615 (m), 594 (s), 560 (vs) cm .
+
–
HRMS (EI, 70 eV): calcd. 762.0454 (for C H F N ), found 762.0426 [M – OTf ].
1
8 10 26 3
C H F N O S (911.32).
19
10 29
3
3
1
,3-Bis(1H,1H,2H,2H-perfluorooctyl)-1,2,3-triazolium
fonyl)imide (1b). Triflate salt 1a (500 mg, 0.55 mmol) was converted with HNTf2
154 mg, 0.55 mmol) according to the general procedure to give compound 1b (557
bis(trifluoromethanesul-
(
mg, 0.530 mmol, 96%) after recrystallization from MTBE (10 mL) as colorless solid,
mp. 41°C. IR (ATR): nu(tilde) = 3170 (w), 3154 (w), 1361 (m), 1347 (m), 1231 (m),
–1
1
176 (s), 1125 (s), 1098 (m), 1058 (s), 810 (m), 698 (m) cm . C H F N O S
20 10 32 4 4 2
(
1042.39): calcd. C 23.05%, H 0.97%, N 5.37%, S 6.15%; found C 23.09%, H 1.30%,
N 5.55%, S 6.51%.
1-Ethyl-3-(1H,1H,2H,2H-perfluorooctyl)-1,2,3-triazolium iodide (2a). A solution of
EtI (526 mg, 3.37 mmol, 4.0 equiv.) and triazole 9 (350 mg, 0.84 mmol, 1.0 equiv.) in
acetone (2 mL) was stirred in a tightly closed reaction tube for 3 h at 130°C. After
evaporation of the volatiles, the residue was recrystallized from MTBE (20 mL) to fur-
1
nish product 2a (474 mg, 0.83 mmol, 99%) as colorless solid, mp. 148°C. H-NMR
(
300 MHz, CD OD): δ = 1.69 (t, J = 7.3 Hz, 3H), 3.18 (tt, J = 18.6 Hz, J = 7.2 Hz, 2H),
3
1
2
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European Journal of Organic Chemistry
10.1002/ejoc.201800582
4.77 (q, J = 7.4 Hz, 2H), 5.12 (t, J = 7.0 Hz, 2H), 8.86 (s, 1H), 8.92 (s, 1H) ppm.
13
1
C{ H}-NMR (125 MHz, CD OD): δ = 14.66 (CH ), 31.30 (t, J = 21.6 Hz, CH ), 47.31
3
3
2
19
1
(
CH ), 50.96 (CH ), 131.76 (CH) 132.56 (CH) ppm. F{ H}-NMR (470 MHz, CD OD):
2 2 3
δ = –82.39 (tt, J = 10.5 Hz, J = 2.5 Hz), (–114.61)–(–115.33) (m), (–122.38)–(–
23.06) (m), (–123.49)–(–124.02) (m), (–124.24)–(–124.72) (m), (–127.01)–(–127.62)
m) ppm. IR (ATR): nu(tilde) = 3124 (w), 3103 (w), 2969 (w), 2955 (w), 1531 (w),
369 (w), 1321 (w), 1306 (w), 1240 (m), 1221 (m), 1183 (s), 1141 (s), 1123 (s), 1075
1
(
1
–1
(
m), 1026 (w), 820 (m), 702 (s) cm . HRMS (EI, 70 eV): calcd. 444.0740 (for
+
3
–
C H F N ), found 444.0744 [M – I ]. C H F IN (571.12).
12
11 13
12 11 13
3
1
-Ethyl-3-(1H,1H,2H,2H-perfluorooctyl)-1,2,3-triazolium
sulfonyl)imide (2b). Iodide salt 2a (300 mg, 0.532 mmol) was converted with HNTf2
93 mg, 0.532 mmol) according to the general procedure to give compound 2b (352
bis(trifluoromethane-
(
mg, 0.486 mmol, 91%) after washing with MTBE (5 mL) as colorless oil. IR (ATR):
nu(tilde) = 3144 (w), 1708 (w), 1348 (m), 1181 (s), 1133 (s), 1055 (s), 791 (m), 616
–1
(
m) cm . C H F N O S (724.36): calcd. C 23.21%, H 1.53%, N 7.73%, S 8.85%;
14 11 19 4 4 2
found C 23.21%, H 1.54%, N 7.66%, S 8.89%.
1
-Ethyl-1,2,3-triazole (11). A solution of EtI (4.51 g, 29.0 mmol, 2.0 equiv.), K CO
2 3
(
4.00 g, 29.0 mmol, 2.0 equiv.) and 1,2,3-triazole 10 (1.00 g, 14.5 mmol, 1.0 equiv.)
in THF (20 mL) was stirred at 23°C for 25 h. The suspension was filtered and all vola-
tiles were removed under reduced pressure. Product 11 (954 mg, 9.82 mmol, 68%)
1
was obtained after distillation (bp. 58°C at 0.33 mbar) as colorless oil. H-NMR (300
MHz, CDCl ): δ = 1.55 (t, J = 7.4 Hz, 3H), 4.44 (q, J = 7.4 Hz, 2H), 7.55 (s, 1H), 7.69
3
13
1
(
s, 1H) ppm. C{ H}-NMR (75 MHz, CDCl ): δ = 15.65 (CH ), 45.23 (CH ), 122.71
3 3 2
(
CH), 133.94 (CH) ppm. IR (ATR): nu(tilde) = 3448 (w), 3122 (w), 2985 (w), 1647 (w),
–1
1
223 (s), 1209 (s), 1117 (s), 1068 (s), 788 (s) cm . HRMS (ESI, pos. mode): calcd.
+
3
+
9
8.0713 (for C H N ), found 98.0715 [M + H ]. C H N (97.12).
4
8
4 7 3
1,3-Diethyl-1,2,3-triazolium iodide (3a). A solution of EtI (1.61 g, 10.3 mmol, 2.0
equiv.) and ethyltriazole 11 (500 mg, 5.15 mmol, 1.0 equiv.) in acetone (2 mL) was
stirred in a tightly closed reaction tube for 3 h at 130°C. After evaporation of the vola-
tiles, the residue was washed with MTBE (10 mL) to furnish product 3a (1.29 g, 5.09
1
mmol, 99%) as yellowish liquid. H-NMR (300 MHz, DMSO-d ): δ = 1.53 (t, J = 7.3
6
1
3
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European Journal of Organic Chemistry
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13
1
Hz, 6H), 4.65 (q, J = 7.3 Hz, 4H), 8.94 (s, 2H) ppm. C{ H}-NMR (75 MHz, DMSO-
d ): δ = 14.12 (2 CH ), 48.66 (2 CH ), 130.33 (2 CH) ppm. IR (ATR): nu(tilde) = 3451
6
3
2
–1
(
s), 3091 (m), 2986 (s), 1450 (s), 1201 (s), 1085 (s), 804 (s) cm . HRMS (ESI, pos.
+
3
–
mode): calcd. 126.1026 (for C H N ), found 126.1031 [M – I ]. C H IN (253.09).
6
12
6
12
3
1,3-Diethyl-1,2,3-triazolium bis(trifluoromethanesulfonyl)imide (3b). Iodide salt
3
a (500 mg, 1.98 mmol) was converted with HNTf (555 mg, 1.98 mmol) according to
2
the general procedure to give compound 3b (785 mg, 1.93 mmol, 98%) after washing
with MTBE (10 mL) as yellowish oil. IR (ATR): nu(tilde) = 3146 (w), 3088 (w), 2995
(
w), 2953 (w), 2849 (w), 1583 (m), 1450 (m), 1342 (s), 1335 (s), 1171 (s), 1132 (s),
–1
1
040 (s), 617 (s) cm . C H F N O S (406.02): calcd. C 23.65%, H 2.98%, N
8 12 6 4 4 2
13.79%, S 15.78%; found C 23.94%, H 3.05%, N 13.70%, S 15.69%.
1
-(1H,1H,2H,2H-Perfluorooctyl)-1,2,4-triazole (13). A solution of R CH CH OTf
F
2
2
(
(
1.80 g, 3.62 mmol, 1.0 equiv.), K CO (1.00 g, 7.24 mmol, 2.0 equiv.) and triazole 12
2 3
250 mg, 3.62 mmol, 1.0 equiv.) in acetone (6 mL) was stirred in at 23°C for 24 h.
MTBE (30 mL) was added and the mixture was washed with water (3 x 50 mL). The
organic layer was dried (MgSO ) and evaporated after filtration. Product 13 (354 mg,
4
0.853 mmol, 53%) was obtained after chromatography (SiO , hexanes/MTBE 1:7, R
2 f
1
=
0.15) as colorless solid, mp. 61°C. H-NMR (300 MHz, DMSO-d ): δ = 2.88 (tt, J =
6
6.7 Hz, J = 19.7 Hz, 2H), 4.56 (t, J = 6.8 Hz, 2H), 8.01 (s, 1H), 8.60 (s, 1H) ppm.
13
1
C{ H}-NMR (125 MHz, DMSO-d ): δ = 29.96 (t, J = 20.8 Hz, CH ), 40.81–40.92 (m,
6
2
19
1
CH ), 144.53 (CH), 151.69 (CH) ppm. F{ H}-NMR (470 MHz, DMSO-d ): δ = (–
2
6
8
0.34 (tt, J = 10.2 Hz, J = 2.6 Hz), (–113.45)–(–113.43) (m), (–121.62)–(–121.98)
m), (–122.54)–(–122.86) (m), (–123.14)–(–123.44) (m), (–125.72)–(–126.04) (m)
ppm. IR (ATR): nu(tilde) = 1187 (s), 1170 (s), 1138 (s), 1078 (s), 709 (s), 687 (s), 639
(
–1
+
(
s), 612 (s) cm . HRMS (EI, 70 eV): calcd. 415.0354 (for C H F N ), found
10 6 13 3
+
4
15.0358 [M ]. C H F N (415.05).
10 6 13 3
1,4-Bis(1H,1H,2H,2H-perfluorooctyl)-1,2,4-triazolium trifluoromethanesulfonate
(
4a). A solution of R CH CH OTf (717 mg, 1.45 mmol, 2.0 equiv.) and triazole 13
F 2 2
(
300 mg, 0.723 mmol, 1.0 equiv.) in acetone (2 mL) was stirred in a tightly closed
reaction tube for 3 h at 130°C. After evaporation of the volatiles, the residue was re-
crystallized from MTBE (10 mL) to furnish product 4a (545 mg, 0.598 mmol, 83%) as
1
4
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European Journal of Organic Chemistry
10.1002/ejoc.201800582
1
colorless solid, mp. 196°C. H-NMR (500 MHz, acetone-d ): δ = 3.13–3.45 (m, 4H),
6
13
1
4
.99–5.22 (m, 4H), 9.45 (s, 1H), 10.49 (s, 1H) ppm. C{ H}-NMR (125 MHz, ace-
19
1
tone-d ): δ = 41.78 (CH ), 45.82 (CH ), 145.07 (CH), 146.28 (CH) ppm. F{ H}-NMR
6
2
2
(
(
(
470 MHz, acetone-d ): δ = –79.42 (s), –82.01 (tt, J = 10.4 Hz, J = 2.6 Hz), –114.51
6
dm), (–122.52)–(–122.78) (m), (–123.53)–(–123.79) (m), (–124.21)–(–124.42) (m),
–126.91)–(–127.13) (m) ppm. IR (ATR): nu(tilde) = 3131 (w), 3083 (w), 1585 (w),
1229 (s), 1201 (s), 1185 (s), 1143 (vs), 1080 (m), 1030 (s), 1009 (m), 707 (m), 695
–1
+
(
m), 638 (s) cm . HRMS (ESI, pos. mode): calcd. 762.0454 (for C H F N ), found
18 10 26 3
–
7
62.0474 [M – OTf ]. C H F N O S (911.32).
19 10 29 3 3
1,4-Bis(1H,1H,2H,2H-perfluorooctyl)-1,2,4-triazolium bis(trifluoromethanesulfo-
nyl)imide (4b). Triflate salt 4a (301 mg, 0.329 mmol) was converted with HNTf (93
2
mg, 0.329 mmol) according to the general procedure to give compound 4b (301 mg,
0.289 mmol, 88%) after washing with MTBE (10 mL) as colorless oil. IR (ATR):
nu(tilde) = 3245 (w), 3099 (w), 3062 (w), 3037 (w), 1704 (m), 1345 (m), 1321 (m),
–1
1
233 (m), 1187 (s), 1142 (s), 1128 (s), 1058 (m), 1058 (m), 708 (m), 697 (m) cm .
C H F N O S (1042.39): calcd. C 23.05%, H 0.97%, N 5.37%, S 6.15%; found C
20
10 32
4
4 2
22.77%, H 1.31%, N 5.16%, S 6.41%.
4-Ethyl-1-(1H,1H,2H,2H-perfluorooctyl)-1,2,4-triazolium iodide (5a). A solution of
EtI (751 mg, 4.81 mmol, 4.00 equiv.) and perfluoroalkyltriazole 13 (500 mg, 1.20
mmol, 1.0 equiv.) in acetone (2 mL) was stirred in a tightly closed reaction tube for 3
h at 130°C. After evaporation of the volatiles, the residue was recrystallized from
MTBE (30 mL) to furnish product 7a (624 mg, 1.09 mmol, 91%) as colorless solid,
1
mp. 208°C. H-NMR (300 MHz, DMSO-d ): δ = 1.46 (t, J = 7.3 Hz, 3H), 3.03 (tt, J =
6
19.5 Hz, J = 7.0 Hz, 2H), 4.32 (q, J = 7.3 Hz, 2H), 4.78 (t, J = 6.9 Hz, 2H), 9.32 (s,
13
1
1
H), 10.24 (s, 1H) ppm. C{ H}-NMR (75 MHz, DMSO-d ): δ = 14.52 (CH ), 29.05 (t,
6
3
J = 20.1 Hz, CH ), 43.25 (CH ), 43.96 (t, J = 4.1 Hz, CH ), 143.15 (CH) 144.67 (CH)
2
2
2
19
1
ppm. F{ H}-NMR (470 MHz, DMSO-d ): δ = –82.39 (tt, J = 10.3 Hz, J = 2.4 Hz), (–
6
1
1
1
14.81)–(–115.07) (m), (–122.69)–(–122.97) (m), (–123.71)–(–122.96) (m), (–
24.30)–(–124.51) (m), (–127.19)–(–127.42) (m) ppm. IR (ATR): nu(tilde) = 3045 (m),
–1
586 (m), 1235 (s), 1201 (vs), 1180 (vs), 1080 (s), 1010 (s), 693 (s), 652 (s) cm .
+
–
HRMS (ESI, pos. mode): calcd. 444.0740 (for C H F N ), found 444.0736 [M – I ].
1
2 11 13 3
C H F IN (571.12).
12
11 13
3
1
5
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European Journal of Organic Chemistry
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4
-Ethyl-1-(1H,1H,2H,2H-perfluorooctyl)-1,2,4-triazolium bis(trifluoromethanesul-
fonyl)imide (5b). Iodide salt 5a (500 mg, 0.875 mmol) was converted with HNTf2
237 mg, 0.84 mmol) according to the general procedure to give compound 5b (625
(
mg, 0.863 mmol, 99%) after recrystallization from MTBE (10 mL) as colorless solid,
mp. 50°C. IR (ATR): nu(tilde) = 3146 (w), 3098 (w), 1585 (w), 1352 (m), 1321 (m),
–1
1
231 (m), 1183 (s), 1058 (s), 1010 (m), 609 (m) cm . C H F N O S (724.36):
14 11 19 4 4 2
calcd. C 23.21%, H 1.53%, N 7.73%, S 8.85%; found C 23.51%, H 1.67%, N 7.47%,
S 8.61%.
1
-Ethyl-1,2,4-triazol (14). A solution of EtI (4.52 g, 29.0 mmol, 2.0 equiv.), K CO
2 3
(
4.01 g, 29.0 mmol, 2.0 equiv.) and 1,2,4-triazole (12) (1.00 g, 14.5 mmol, 1.0 equiv.)
in acetone (10 mL) was stirred at 23°C for 21 h. The suspension was filtered and all
volatiles were removed under reduced pressure. Product 14 (851 mg, 8.76 mmol,
1
6
0%) was obtained after distillation (40 mbar, 86°C) as colorless oil. H-NMR (500
MHz, CDCl ): δ = 1.41 (t, J = 7.3 Hz, 3H), 4.12 (q, J = 7.2 Hz, 2H), 7.82 (s, 1H), 7.98
3
1
3
1
(
(
s, 1H) ppm. C{ H}-NMR (125 MHz, CDCl ): δ = 14.95 (CH ), 44.51 (CH ), 142.13
3 3 2
CH), 151.72 (CH) ppm. IR (ATR): nu(tilde) = 3474 (w), 3396 (w), 3119 (w), 2989 (w),
648 (w), 1509 (vs), 1274 (vs), 1207 (s), 1140 (vs), 1012 (s), 959 (s), 682 (vs), 671
1
–1
+
(
vs), 645 (s) cm . HRMS (ESI, pos. mode): calcd. 98.0713 (for C H N ), found
4 8 3
+
9
8.0720 [M + H ]. C H N (97.12).
4 7 3
1-Ethyl-4-(1H,1H,2H,2H-perfluorooctyl)-1,2,4-triazolium
trifluoromethanesulfo-
nate (6a). A solution of R CH CH OTf (2.04 g, 4.12 mmol, 2.0 equiv.) and ethyl-
F
2
2
triazole 14 (200 mg, 2.06 mmol, 1.0 equiv.) in acetone (5 mL) was stirred in a tightly
closed reaction tube for 3 h at 130°C. After evaporation of the volatiles, the residue
was recrystallized from MTBE (50 mL) to furnish product 6a (972 mg, 1.64 mmol,
1
8
0%) as colorless solid, mp. 152°C. H-NMR (300 MHz, DMSO-d ): δ = 1.47 (t, J =
6
7.3 Hz, 3H), 2.90–3.21 (m, 2H), 4.42 (q, J = 7.1 Hz, 2H), 4.64 (t, J = 7.6 Hz, 2H), 9.26
1
3
1
(
(
(
(
s, 1H), 10.17 (s, 1H) ppm. C{ H}-NMR (75 MHz, DMSO-d ): δ = 13.57 (CH ), 29.81
6 3
t, J = 20.5 Hz, CH ), 39.56 (CH ), 47.27 (CH ), 120.67 (q, J = 322.1 Hz; CF ), 142.65
2
2
2
3
19
1
CH) 144.91 (CH) ppm. F{ H}-NMR (470 MHz, DMSO-d ): δ = –78.03 (s), –82.56
6
tt, J = 10.1 Hz, J = 2.6 Hz), (–113.00)–(–113.50) (m), (–121.58)–(–122.06) (m), (–
122.56)–(–123.07) (m), (–123.28)–(–123.64) (m), (–125.82)–(–126.32) (m) ppm. IR
1
6
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European Journal of Organic Chemistry
10.1002/ejoc.201800582
(
(
ATR): nu(tilde) = 3135 (w), 3080 (w), 2998 (w), 1585 (m), 1364 (m), 1242 (s), 1226
–1
s), 1188 (s), 1168 (s), 1081 (m), 1031 (s), 997 (m), 694 (m) cm . HRMS (ESI, pos.
+
–
mode): calcd. 444.0740 (for C H F N ), found 444.0741 [M – OTf ].
1
2 11 13 3
C H F N O S (593.28).
13
11 16
3
3
1
-Ethyl-4-(1H,1H,2H,2H-perfluorooctyl)-1,2,4-triazolium
sulfonyl)imide (6b). Triflate salt 6a (500 mg, 0.84 mmol) was converted with HNTf2
237 mg, 0.84 mmol) according to the general procedure to give compound 6b (580
bis(trifluoromethane-
(
mg, 0.80 mmol, 95%) after recrystallization from MTBE (10 mL) as colorless solid,
mp. 51°C. IR (ATR): nu(tilde) = 3146 (w), 3099 (w), 1586 (m), 1352 (m), 1321 (m),
–1
1
183 (s), 1057 (s), 1009 (m), 652 (m) cm . C H F N O S (724.36): calcd. C
14 11 19 4 4 2
23.21%, H 1.53%, N 7.73%, S 8.85%; found C 23.59%, H 1.82%, N 7.54%, S 8.72%.
1,4-Diethyl-1,2,4-triazolium iodide (7a). A solution of EtI (643 mg, 4.12 mmol, 2.0
equiv.) and ethyltriazole 14 (200 mg, 2.06 mmol, 1.0 equiv.) in acetone (12 mL) was
stirred in a tightly closed reaction tube for 2 h at 130°C. After evaporation of the vola-
tiles, the residue was recrystallized from hexanes/MTBE (1:1, 10 mL) to furnish pro-
1
duct 7a (280 mg, 2.20 mmol, 54%) as colorless solid, mp. 84°C. H-NMR (300 MHz,
DMSO-d ): δ = 1.46 (t, J = 7.2 Hz, 6H), 4.26 (q, J = 7.3 Hz, 2H), 4.38 (q, J = 7.3 Hz,
6
13
1
2
H), 9.23 (s, 1H), 10.13 (s, 1H) ppm. C{ H}-NMR (125 MHz, DMSO-d ): δ = 13.64
6
(
CH ), 14.46 (CH ), 42.99 (CH ), 47.08 (CH ), 141.89 (CH), 144.34 (CH) ppm. IR
3 3 2 2
(
ATR): nu(tilde) = 3031 (m), 2998 (s), 2980 (s), 2882 (w), 1776 (w), 1579 (s), 1340
–1
(
s), 1172 (s), 997 (s), 966 (s), 702 (s), 626 (s) cm . HRMS (ESI, pos. mode): calcd.
+
–
1
26.1026 (for C H N ), found 126.1030 [M – I ]. C H IN (253.09).
6 12 3 6 12 3
1,4-Diethyl-1,2,4-triazolium bis(trifluoromethanesulfonyl)imide (7b). Iodide salt
7
a (61 mg, 0.241 mmol) was converted with HNTf (68 mg, 0.241 mmol) according to
2
the general procedure to give compound 7b (81 mg, 0.199 mmol, 83%) after washing
with MTBE (5 mL) as colorless oil. IR (ATR): nu(tilde) = 3143 (w), 3090 (w), 2995 (w),
2954 (w), 2922 (w), 2853 (w), 1580 (m), 1454 (m), 1347 (s), 1329 (s), 1179 (s), 1132
–1
(
s), 1051 (s), 790 (m), 741 (m), 612 (s) cm . C H F N O S (406.02): calcd. C
8 12 6 4 4 2
2
3.65%, H 2.98%, N 13.79%, S 15.78%; found C 23.41%, H 2.96%, N 13.71%, S
5.95%.
1
1
7
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European Journal of Organic Chemistry
10.1002/ejoc.201800582
Acknowledgement
This work was funded by the "Zentrales Innovationsprogramm Mittelstand (ZIM)" of
the "Bundesministerium for Wirtschaft und Energie (BMWi)" (Germany). MTBE was
obtained as a generous gift from Evonik Industries, Marl, Germany. We grateful to
Lukas Hakelberg-Pekol for experimental support.
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