Perfluorinated Pyridinium and Imidazolium ionic liquids

Article abstract of DOI:10.1002/ejoc.201700717

Ionic liquids with perfluorinated side chains were prepared as hybrid materials for surface impregnation. For the cationic part, methyl and ethyl pyridinium as well as imidazolium scaffolds were used. The anions investigated were hydroxide, acetate, trifluoroacetate, triflate, triflimide, chloride, bromide, iodide, hydrogensulfate, and perfluorododecanoate. A key feature of this investigation is the finding that the use of relatively short perfluorohexyl residues as the fluorinated part of the salts is beneficial for the target compounds compared with established products, because of their lower bioaccumulativity. One compound yielded single crystals that were suitable for X-ray structure analysis, revealing a layered structure with relatively well-resolved, hard ionic domains alternating with disordered, soft perfluorinated layers. The wettability of all 30 materials was investigated by water contact angle measurements of a thin film on a glass surface. In two cases, promising contact angles (130° and 140°) were observed, indicating that the products might be suitable candidates for the impregnation of surfaces.

Full text of DOI:10.1002/ejoc.201700717

A Journal of
Accepted Article
Title: Perfluorinated Pyridinium and Imidazolium Ionic Liquids
Authors: Torben Alpers, Marc Schmidtmann, Thomas W. T.
Muesmann, Oliver Temme, and Jens Christoffers
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To be cited as: Eur. J. Org. Chem. 10.1002/ejoc.201700717
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10.1002/ejoc.201700717
European Journal of Organic Chemistry
Perfluorinated Pyridinium and Imidazolium Ionic Liquids
Torben Alpers,[a,b] Marc Schmidtmann,[a] Thomas W. T. Muesmann,[b] Oliver
Temme,[b] Jens Christoffers*[a]
[a] M.Sc. T. Alpers, Dr. M. Schmidtmann, 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
O
O
F13C6
C6F13
O
O
N
N
F13C6
C6F13
N
R
X
X
R = Me, Et
X = I, HO,
AcO, CF3CO2, TfO, Tf2N,
Cl, Br, HSO4, CF3(CF2)10CO2
Pyridinium and imidazolium ionic liquids with perfluorinated side chains and different
anions were prepared.
Abstract: Ionic liquids with perfluorinated side chains are prepared as hybrid
materials for surface impregnation. For the cationic part, methyl and ethyl pyridinium
as well as imidazolium scaffolds are used. The anions are hydroxide, acetate, trifluo-
roacetate, triflate, triflimide, chloride, bromide, iodide, hydrogensulfate, and perfluoro-
dodecanoate. The key feature of this investigation are relatively short perfluorohexyl
residues as the fluorinated part of the salts, making the target compounds beneficial
alternatives to established products because of their lower bioaccumulativity. One
compound yielded single crystals suitable for X-ray structure analysis revealing a
layered structure with relatively well-resolved, hard ionic domains alternating with dis-
ordered, soft perfluorinated layers. The wettability of all 30 materials was investigated
1
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10.1002/ejoc.201700717
European Journal of Organic Chemistry
by water contact angle measurements of a thin film on a glass surface. In two cases,
promising contact angles (130° and 140°) were observed indicating, that the products
might be suitable candidates for the impregnation of surfaces.
Keywords: Ionic Liquids, Fluorine compounds, Wettability, Pyridine derivatives,
Imidazole derivatives.
Introduction
Ionic liquids[1] and perfluorinated solvents[2] are neoteric solvents, which are often
associated with sustainable processes and green chemistry,[3] although their benefits
are sometimes critically discussed.[4] The combination of both, i.e. ionic liquids with
perfluorinated side chains,[5] has been realized in a few cases. Most of them utilize
perfluorocarboxylic acids as anions,[6] but also perfluorinated cations have been re-
ported.[7] Fluorinated quaternary phosphonium salts were reported to be super-hydro-
phobic materials[8] with contact angles up to 168°.[9]
As a manufacturer of water repellent textile coatings, the latter materials property
attracted our particular attention, since we are aiming at identifying new compounds
with shorter perfluoroalkyl side chains. The compounds used in this field of appli-
cation so far, perfluoroalkyl carboxylic and sulfonic acids with longer carbon chains
(CnF2n+1CO2H and CnF2n+1SO3H with n > 6) and derivatives thereof, came into the
focus of environmental concerns. The most prominent representatives of these
compound classes are PFOA (C7F15CO2H) and PFOS (C8F17SO3H), which have
found ubiquitous applications for surface treatment of textiles, leathers, cardboard,
paper, polymeric materials, metals etc.[10] Especially so called fluorocarbon resins are
widely in use as impregnation materials for industrial as well as consumer[11] appli-
cations. Although PFOA and PFOS itself are quite harmless since chemically inert,
they are for the same reason persistent, they pollute the environment and are accu-
mulated in the biosphere. Meanwhile they are detectable ubiquitously in the abiotic
environment[12] as well as in animals and humans[13] and have thus attracted
attention as global contaminants. These compounds were consequently listed under
Annex B (restriction of production and use) of the Stockholm Convention in 2009.[14]
Furthermore, the European Chemicals Agency lists PFOA on the SVHC Candidate
List as a CMR-substance (SVHC = substance of very high concern; CMR =
2
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10.1002/ejoc.201700717
European Journal of Organic Chemistry
carcinogenic, mutagenic, or toxic for reproduction).[15] The chemical industry started
off several initiatives for identifying replacements for perfluoroalkyl materials.[16]
A
reasonable alternative are shorter chain compounds with C6F13 or C4F9 residues,
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
degradability. We propose that both features could be addressed by pyridinium and
imidazolium ionic liquids with perfluorohexyl chains (nC6F13). Whereas the pyridinium
scaffold has so far not been equipped with fluorinated residues, the imidazolium core
has been with targeting the development of new fluorinated N-heterocyclic carbene
ligands for homogeneous catalysis.[17] Herein we wish to disclose the synthesis of a
small series of 30 fluorinated ionic liquids based on the two pyridinium cations 1 and
2 as well as the imidazolium cation[18] 3 (Figure 1). In order to access a rather divers
set of compounds for screening the material properties, we have focused on the
exchange of anions.[19]
O
O
RF
RF
O
O
N
N
RF
RF
N
R
X
X
R = C F
13
3
1 (R = Me),
(R = Et)
n
F
6
2
X = I, HO,
AcO, CF3CO2, TfO, Tf2N,
Cl, Br, HSO4, CF3(CF2)10CO2
Figure 1. Target compounds of this study.
Results and Discussion
Pyridinium Cations. The synthesis of pyridinium compounds proceeded from the
acid chloride, which was obtained from 3,5-pyridine dicarboxylic acid 4 with an
excess of SOCl2. Conversion with RFCH2CH2OH (RF = nF13C6) without additional
solvent furnished the fluorinated diester 5 in 93%, as reported before (Scheme 1).[20]
The alkylation with an excess of MeI and EtI, resp., required relatively high concen-
tration (1 mol/L in acetone) and temperature (150°C), therefore, the reaction was
performed in a tightly closed reaction vial. The pyridinium iodides 1a and 2a were
obtained in 89% and 74% yields, resp., after crystallization from MTBE (tert-butyl-
methylether). These two compounds were fully characterized. Efforts to prepare the
N-butyl congener from nBuI were less successful (10% yield after crystallization),
3
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10.1002/ejoc.201700717
European Journal of Organic Chemistry
therefore, this compound was not investigated further.
O
O
HO2C
CO2H
RF
RF
(a)
O
O
N
N
4
R = C F
5 (93%)
n
F
6 13
(b)
O
O
RF
RF
O
O
N
R
X
1a (89%; R = Me, X = I),
2a (74%; R = Et, X = I),
(c)
(d)
1c-1j (98-100%; R = Me),
2c-2j (81-100%; R = Et)
1b (98%; R = Me, X = OH),
2b (100%; R = Et, X = OH)
Scheme 1. Preparation of pyridinium salts. Reagents and conditions: (a) 1. xs.
SOCl2, cat. DMF, 90°C, 16 h; 2. 2.2 equiv. nF13C6CH2CH2OH, 90°C, 96
h; (b) 14 equiv. MeI or 11 equiv. EtI, acetone, 150°C, 3 h; (c) hydroxide
loaded resin Lewatit Mono MP Plus 800; (d) + 1.0 equiv. HX in MeOH,
anions X: AcO (c), CF3CO2 (d), TfO (e), Tf2N (f), Cl (g), Br (h), HSO4 (i),
CF3(CF2)10CO2 (j).
Iodide ions from salts 1a and 2a were changed to hydroxide by using a column of
hydroxide-loaded ion exchange resin. First of all, the hydroxides 1b and 2b were
obtained after elution from the column with MeOH and evaporation of their solutions;
yields of anhydrous materials were quantitative (98–100%). All other salts 1c–1j and
2c–2j were prepared from the MeOH solutions of hydroxides 1b and 2b with a
stoichiometric amount of the respective Brønsted acids HX as MeOH solutions
(except Tf2NH, which was used neat), as were AcOH (c), CF3CO2H (d), TfOH (e),
Tf2NH (f), HCl (g), HBr (h), H2SO4 (0.50 equiv.) (i). Furthermore, the perfluorodode-
canoic acid, CF3(CF2)10CO2H (j), was used, also in neat form. In all 16 cases, the
products 1c–1j and 2e–2j were obtained in 96–100% yields as analytically pure ma-
terials, except compounds 2c (81%) and 2d (83%), which required recrystallization
from MTBE to obtain analytically pure materials. Compounds 1b–1j and 2b–2j gave
the same NMR and mass spectra as their parent iodides 1a and 2a, therefore, only
4
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10.1002/ejoc.201700717
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IR data and combustional analyses are given in the experimental section.
Although perfluorinated compounds are generally regarded to be difficult to cry-
stallize, we were able to obtain single crystals of compound 2a suitable for X-ray
structure determination at T = 170 K.[21] Compound 2a crystallized in the monoclinic
space group P21/n with a = 750.40(2) pm, b = 4784.12(15) pm, c = 967.17(3) pm, α =
90°, β = 93.3645(15)°, γ = 90°. An ORTEP representation of the molecular structure
is given in Figure 2. Whereas the pyridinium part of the molecular cation appears well
resolved, the anisotropic atomic displacement parameters become larger towards the
end of the fluorinated chain. In addition, the perfluoroalkyl chains are disordered as
shown in Figure 3, a clear indication of the PTFE-like nature of the perfluoroalkyl
chains which originates from the extraordinarily weak intermolecular forces.
Figure 2.
ORTEP-representation of the X-ray structure of compound 2a in the
solid state, ellipsoids at the 50% probability level, H atoms and disor-
dered atoms were omitted for clarity; color code: carbon gray, fluorine
green, iodine violet, nitrogen blue, oxygen red.
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10.1002/ejoc.201700717
European Journal of Organic Chemistry
Figure 3.
Structure of compound 2a including the disorder of the ethyl group and
of the perfluoroalkyl chains.
Figure 4 shows the crystal packing of compound 2a. The unit cell is depicted with
black lines (Z = 4); view along the a-axis; the horizontal edge is the b-axis. The com-
pound exhibits a layered structure of alternating ionic and fluorinated domains in the
ac-plane. The pyridinium iodide units define the "hard" ionic domains, which are well
resolved. In contrast, the "soft" fluorinated domains show large displacement para-
meters and disorder (cf. Figure 3).
6
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10.1002/ejoc.201700717
European Journal of Organic Chemistry
Figure 4.
ORTEP-representation of the packing of compound 2a in the unit cell.
Imidazolium Cation. In order to access a perfluoroalkylated imidazolium deriva-
tive[18] we first tried to dialkylate imidazole 8 with the triflate 7, derived from the
alcohol nF13C6CH2CH2OH according to a known procedure,[22] but we failed. We then
turned to 1-trimethylsilylimidazole (6), which was reported to give superior results in
alkylation reactions,[23] and we were indeed able to isolate the triflate salt 3e in 35%
yield after recrystallization. Apart from the higher costs of the TMS-derivative 6, this
method did not convince us due to the relatively low yield. Therefore, we investigated
the alkylation with iodo compound 9 as starting material, and indeed imidazole 8
could be alkylated twice and the iodide 3a was obtained in 44% yield after
crystallization. The anion exchange was performed as established for the synthesis
of the pyridinium derivatives: After procuring the hydroxide 3b, and respective MeOH
solution was neutralized with the respective Brønsted acids HX yielding the com-
pounds 3c–3j all in quantitative yields (96–100%) and analytically pure materials, ex-
cept the triflate 3e, which was obtained in 35% yield after recrystallization (IR and
combustion analysis are given in the experimental section). The NMR and mass
spectra of all compounds 3a–3j appear equal; respective data for compound 3e are
given in the experimental section.
7
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10.1002/ejoc.201700717
European Journal of Organic Chemistry
(a)
N
N
N
N
N
TMS
RF
RF
RF
OTf
TfO
3e (35%)
6
7
R = C F
n
F
6
13
(b)
N
N
HN
RF
RF
RF
I
X
3a (44%, X = I)
8
3c, 3d, 3f-3j (96-100%)
9
(c)
3b (quant., X = OH)
(d)
Scheme 2. Preparation of imidazolium salts. Reagents and conditions: (a) 2.5
equiv. nF13C6CH2CH2OTf, 60°C, 24 h; (b) 2.2 equiv. nF13C6CH2CH2I, toluene, 110°C,
24 h; (c) hydroxide loaded resin Lewatit Mono MP Plus 800; (d) + 1.0 equiv. HX in
H2O, anions X: AcO (c), CF3CO2 (d), TfO (e), Tf2N (f), Cl (g), Br (h), HSO4 (i),
CF3(CF2)10CO2 (j).
Physical Properties. In order to obtain a first impression of water repellency of the
new products we have investigated the wettability of a thin film spread on a glass sur-
face by measuring the water contact angle.[8] Figure 5 shows a representative photo-
graph of the droplet on the surface impregnated with compound 1a. Table 1 lists the
average of left and right angle together with the melting point and the calculated fluo-
rine content. Obviously, no correlation can be derived from the angles and the two
other pieces of data. A great influence has of course the anion of the respective salt
as well as the constitution of the cation. Even small changes like methyl replaced by
ethyl results in significant changes of the contact angle, as is particularly obvious by
comparison of compounds 1a and 2a (140° and 62°, resp.). Actually, compound 1a
(Figure 5) is the only example which fulfilled out expectations completely. All other
compounds with perfluorohexyl moieties showed contact angles below 110°. Higher
values were obtained with the perfluorododecanoate anion (series j), however, the
aim of our efforts is to abolish such compounds from future applications. Anyhow,
with methylpyridinium compound 1a we have a promising candidate for a material
suitable for textile impregnation in our hand, which is expected to be – as a benefit of
shorter perfluoroalkyl chains – bio-degradable. We are presently investigating its
application, in particular the question whether an iodide salt shows long term stability
under aerobic conditions.
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Table 1. Selected properties of fluorinated compounds 1a–1j, 2a–2j and 3a–3j: Melting points (mp.), fluorine content (F/% w/w;
calculated) and water contact angles () (the average value between left and right angle together with its span width is given).
Methylpyridinium cation 1
Ethylpyridinium cation 2
Imidazolium cation 3
Anion
mp./°C
F/% w/w
mp./°C
F/% w/w
mp./°C
F/% w/w
/°
/°
/°
I– (a)
193
79
135
157
122
66
151
161
126
81
49.3
55.4
52.9
55.8
53.8
52.7
54.3
51.8
53.6
62.6
182
57
132
152
136
51
141
154
112
59
48.7
54.6
52.1
55.0
53.1
52.0
53.5
51.0
50.1
62.0
>300
55.6
63.5
60.2
64.2
60.6
58.4
62.0
58.7
57.6
67.7
140.50.1
62.40.3
127.90.0
98.82.3
[a]
[b]
[c]
HO– (b)
AcO– (c)
–
–
–
–
–
[a]
[b]
[c]
[b]
–
–
–
–
[c]
CF3CO2 (d)
38.51.1
42.43.2
79.32.2
95.80.2
80.21.8
31.80.3
109.70.1
24.70.9
91.00.0
87.60.3
101.60.4
108.30.3
8.80.6
69.61.1
88.71.7
69.41.1
94.00.5
TfO– (e)
Tf2N– (f)
Cl– (g)
163
54
172
249
83
Br– (h)
–
[b]
[b]
HSO4 (i)
–
–
–
CF3(CF2)10CO2 (j)
125
113.80.0
115.90.1
[a]
dissolves in water, [b] the angles are less 5° due to good wettability of the surface, [c] not a solid at ambient temperature.
9
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10.1002/ejoc.201700717
European Journal of Organic Chemistry
Figure 5. Shape of a water droplet on a glass surface coated with compound 1a;
contact angles are 140.4° and 140.6°, resp.
Summary. In the course of our efforts to develop perfluorinated compounds for
textile impregnation as alternatives to PFOA (C7F15CO2H) and PFOS (C8F17SO3H),
we have prepared 30 (three series of 10 compounds each) new hybrid materials as
ionic liquids with perfluoro-n-hexyl moieties. In the first and second series,
bis(tridecafluorohexyl) 3,5-pyridine dicarboxylate (5) was alkylated with MeI and EtI to
yield the respective pyridinium iodides 1a (89%) and 2a (74%). For the third series,
imidazole (8) was alkylated twice with nC6F13CH2CH2I (9) to furnish the respective
imidazolium iodide 3a (44%). All three compounds 1a, 2a, and 3a were then sub-
mitted to anion exchange on a hydroxide-loaded Lewatit Mono MP Plus 800 resin to
give the respective hydroxide salts 1b, 2b, and 3b, all with quantitative yields. These
hydroxides were then neutralized with the Brönsted acids AcOH (c), CF3CO2H (d),
TfOH (e), Tf2NH (f), HCl (g), HBr (h), H2SO4 (i), CF3(CF2)10CO2H (j) to furnish the
salts 1c–1j, 2c–2j, and 3c–3j with quantitative yields (96–100% with three
exceptions) and as analytically pure materials (combustion analysis). Compounds 2c
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European Journal of Organic Chemistry
(81%), 2d (83%), and 3e (35%) required recrystallization to achieve analytical purity.
Ethylpyridinium iodide 2a is a crystalline compound and was suitable for single
crystal X-ray structure analysis, which is unusual for perfluorinated compounds. As
shown in the ORTEP plots, the crystallinity originates from ionic interactions within
the pyridinium iodide part of the compound and is well resolved. The perfluorohexyl
side chains are highly disordered and exhibit large anisotropic displacement para-
meters indicating the expected weak intermolecular forces. In the solid state, com-
pound 2a forms a layered structure within the crystal where the well-resolved ionic
sides alternate with the disordered perfluorinated side chains.
As a first survey of their property profile, we have investigated the wettability of all 30
compounds 1a–1j, 2a–2j, and 3a–3j by water contact angle measurements of a thin
film on a glass surface. In two cases, promising contact angles were observed (140°
for compound 1a, 130° for compound 3a) indicating, that the products might be suit-
able candidates for the impregnation of surfaces. Further studies are in progress in
our laboratories, in particular, studies on the biodegradability of the new compounds.
The latter shall actually be the key property of the new materials. With their relatively
short perfluoroalkyl side chains and therefore low bioaccumulativity, the target com-
pounds might be beneficial alternatives to established products, like PFOA and
PFOS.
Experimental Section
1
General: H-, 19F- and 13C-NMR spectra were recorded on a Bruker Avance DRX
500 instrument. Multiplicities of carbon signals were determined with DEPT experi-
ments. MS and HRMS spectra of products were obtained with a Waters Q-TOF Pre-
mier (ESI) spectrometer. IR spectra were recorded on a Bruker Tensor 27 spectro-
meter 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. Diester 5[20] and nC6F13CH2CH2OTf (7)[22] were pre-
pared according to literature protocols. All other starting materials were commercially
available. In particular, nC6F13CH2CH2I was purchased from Apollo,
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European Journal of Organic Chemistry
nC6F13CH2CH2OH from DuPont, and CF3(CF2)10CO2H from Matrix Scientific.
1-Methyl-3,5-bis(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctanoyl)pyridinium iodide
(1a). A solution of MeI (10 mL, 22.8 g, 161 mmol, 14 equiv.) and pyridine dicarboxy-
late 5 (9.67 g, 11.3 mmol, 1.0 equiv.) in acetone (10 mL) was stirred in a tightly
closed reaction tube for 3 h at 150°C. After evaporation of the volatiles, the residue
was recrystallized from tert-butylmethylether (MTBE) (20 mL) to furnish the product
1
1a (10.0 g, 9.98 mmol, 89%) as yellow solid, mp. 193°C. H-NMR (500 MHz,
CD3OD): δ = 2.86 (tt, J = 19.0 Hz, J = 6.2 Hz, 4H), 4.59 (s, 3H), 4.82 (t, J = 6.0 Hz,
13
4H), 9.34 (t, J = 1.6 Hz, 1H), 9.74 (d, J = 1.6 Hz, 2H) ppm. C{1H}-NMR (125 MHz,
CD3OD): δ = 31.07 (2 CH2), 49.90 (CH3), 60.22 (2 CH2), 131.85 (2 C), 145.49 (CH),
151.29 (2 CH), 161.72 (2 C) ppm. 19F-NMR (470 MHz, CD3OD): δ = –82.43 (tt, J =
3.0 Hz, J = 10.4 Hz, 6F), (–114.45)–(–114.62) (m, 4F), (–122.59)–(–122.97) (m, 4F),
(–123.72)–(–123.98 (m, 4F), (–124.36)–(–124.59) (m, 4F), (–127.14)–(–127.38) (m,
4F) ppm. IR (ATR): nu(tilde) = 2994 (w), 2932 (w), 1742 (s), 1647 (w), 1608 (w),
1500 (w), 1470 (w), 1350 (m), 1322 (m), 1233 (s), 1191 (s), 1143 (s), 1078 (s), 1006
(m), 844 (m), 740 (s), 699 (s), 656 (s) cm–1. HR-MS (ESI, pos. mode): calcd.
874.0502 (for C24H14F26NO4), found 874.0512 [M+ – I]. C24H14F26INO4 (1001.24):
calcd. C 28.79%, H 1.41%, N 1.40%; found C 29.04%, H 1.28%, N 1.46%.
General procedure: Exchange of Anions. A column of ion-exchange resin Lewatit
Mono MP Plus 800 (Lanxess, capacity ca. 0.95 mmol/g) (20 g) was regenerated prior
to each use by the following sequential washings: (1) with hydrochloric acid (10 mL, 2
mol L–1) until to pH = 1 of the eluent, (2) with water until pH = 7, (3) with aq. NaOH
(10 mL, 2 mol L–1) until pH = 13–14 and finally (4) again with water to pH = 7.
A solution of the iodide salts 1a, 2a (0.50 mmol, 500 mg or 507 mg, resp.) in 5 mL
MeOH (ca. 60°C warm) or 3a (1.00 mmol, 888 mg) in 10 mL MeOH (ambient tempe-
rature) was transferred on top of the column and the hydroxide salts 1b, 2b or 3b
eluted with methanol, until to pH = 7 of the eluent; the eluted volume ranged between
5 mL and 50 mL.
1-Methyl-3,5-bis(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctanoyl)pyridinium
hydroxide (1b). Iodo compound 1a (500 mg, 0.50 mmol) was converted according to
the General Procedure to furnish compound 1b (437 mg, 0.49 mmol, 98%) after eva-
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10.1002/ejoc.201700717
European Journal of Organic Chemistry
poration of the solvent as colorless solid, mp. 79°C. IR (ATR): nu(tilde) = 3434 (w),
2972 (w), 1669 (m), 1620 (m), 1546 (w), 1322 (w), 1201 (s), 1169 (s), 1081 (s), 1034
(w), 993 (m), 842 (m), 748 (m), 698 (m) cm–1. C24H15F26NO5 (891.34): calcd. C
32.34%, H 1.70%, N 1.57%; found C 32.69%, H 1.74%, N 1.54%.
1-Methyl-3,5-bis(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctanoyl)pyridinium
acetate (1c). A solution of compound 1b in MeOH obtained from iodo compound 1a
(500 mg, 0.50 mmol) according to the General Procedure was neutralized with acetic
acid (0.50 mL of a 1 mol L–1 solution in MeOH) to furnish acetate 1c (458 mg, 0.49
mmol, 98%) after evaporation of the solvent as a colorless solid, mp. 135°C. IR
(ATR): nu(tilde) = 3082 (w), 1732 (m), 1685 (s), 1341 (m), 1233 (m), 1180 (s), 1141
(s), 1122 (s), 1079 (s), 997 (m), 828 (m), 696 (m) cm–1. C26H17F26NO6 (933.38):
calcd. C 33.46%, H 1.84%, N 1.50%; found C 33.31%, H 2.04%, N 1.73%.
1-Methyl-3,5-bis(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctanoyl)pyridinium
tri-
fluoroacetate (1d). A solution of compound 1b in MeOH obtained from iodo com-
pound 1a (500 mg, 0.50 mmol) according to the General Procedure was neutralized
with trifluoroacetic acid (0.5 mL of a 1 mol L–1 solution in MeOH) to furnish trifluoro-
acetate 1d (484 mg, 0.50 mmol, 100%) after evaporation of the solvent as a light
yellow solid, mp. 157°C. IR (ATR): nu(tilde) = 3027 (w), 1752 (m), 1739 (s), 1685 (s),
1467 (w), 1384 (w), 1342 (m), 1322 (w), 1232 (s), 1188 (vs), 1142 (vs), 1124 (s),
1078 (s), 842 (m), 821 (m), 747 (m), 735 (m), 697 (s), 651 (m) cm–1. C26H14F29NO6
(971.35): calcd. C 31.63%, H 1.43%, N 1.42%; found C 31.41%, H 1.45%, N 1.56%.
1-Methyl-3,5-bis(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctanoyl)pyridinium
tri-
fluoromethanesulfonate (1e). A solution of compound 1b in MeOH obtained from
iodo compound 1a (500 mg, 0.50 mmol) according to the General Procedure was
neutralized with trifluoromethanesulfonic acid (0.5 mL of a 1 mol L–1 in solution in
MeOH) to furnish triflate 1e (511 mg, 0.50 mmol, 100%) after evaporation of the sol-
vent as a colorless solid, mp. 122°C. IR (ATR): nu(tilde) = 3011 (w), 1750 (m), 1737
(m), 1657 (w), 1685 (w), 1385 (w), 1342 (m), 1272 (s), 1253 (s), 1227 (s), 1191 (vs),
1142 (vs), 1124 (vs), 1078 (s), 1032 (s), 736 (m), 697 (s), 639 (s) cm–1.
C25H14F29NO7S (1023.40): calcd. C 29.34%, H 1.38%, N 1.37%, S 3.13%; found C
29.10%, H 1.44%, N 1.39%, S 3.23%.
13
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1-Methyl-3,5-bis(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctanoyl)pyridinium
bis-
(trifluoromethanesulfonyl)amide (1f). A solution of compound 1b in MeOH ob-
tained from iodo compound 1a (500 mg, 0.50 mmol) according to the General Proce-
dure was neutralized with bis(trifluoromethanesulfonyl)imide (140 mg, 0.50 mmol) to
furnish the triflimide 1f (564 mg, 0.49 mmol, 98%) after evaporation of the solvent as
a colorless solid, mp. 66°C. IR (ATR): nu(tilde) = 3098 (w), 1741 (m), 1346 (m), 1231
(m), 1182 (vs), 1133 (s), 1059 (s), 842 (m), 740 (m), 651 (m), 616 (m) cm–1.
C26H14F32N2O8S2 (1154.47): calcd. C 27.05%, H 1.22%, N 2.43%, S 5.55%; found C
27.03%, H 1.52%, N 2.69%, S 5.22%.
1-Methyl-3,5-bis(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctanoyl)pyridinium chlori-
de (1g). A solution of compound 1b in MeOH obtained from iodo compound 1a (500
mg, 0.50 mmol) according to the General Procedure was neutralized with hydro-
chloric acid (0.5 mL of a 1 mol L–1 solution in MeOH containing some water) to fur-
nish the chloride 1g (456 mg, 0.50 mmol, 100%) after evaporation of the solvent as a
colorless solid, mp. 151°C. IR (ATR): nu(tilde) = 1736 (s), 1610 (w), 1339 (m), 1320
(m), 1231 (s), 1189 (vs), 1141 (vs), 1076 (s), 991 (w), 914 (w), 842 (w), 812 (w), 782
(w), 746 (m), 731 (s), 697 (s), 650 (s), 602 (m) cm–1. C24H14ClF26NO4 (909.79): calcd.
C 31.68%, H 1.55%, N 1.54%; found C 31.56%, H 1.73%, N 1.83%.
1-Methyl-3,5-bis(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctanoyl)pyridinium bro-
mide (1h). A solution of compound 1b in MeOH obtained from iodo compound 1a
(500 mg, 0.50 mmol) according to the General Procedure was neutralized with hydro-
bromic acid (0.5 mL of a 1 mol L–1 solution in MeOH containing some water) to
furnish the bromide 1h (467 mg, 0.49 mmol, 98%) after evaporation of the solvent as
a colorless solid, mp. 161°C. IR (ATR): nu(tilde) = 1724 (s), 1345 (m), 1318 (m), 1235
(s), 1188 (vs), 1141 (vs), 1077 (s), 1038 (w), 1001 (w), 956 (w), 841 (m), 782 (w), 744
(m), 734 (m), 699 (m), 638 (s) cm–1. C24H14BrF26NO4 (954.24): calcd. C 30.21%, H
1.48%, N 1.47%; found C 30.15%, H 1.87%, N 1.64%.
1-Methyl-3,5-bis(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctanoyl)pyridinium
hydrogensulfate (1i). A solution of compound 1b in MeOH obtained from iodo com-
pound 1a (500 mg, 0.50 mmol) according to the General Procedure was neutralized
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with sulfuric acid (0.5 mL of a 1 mol L–1 solution in MeOH) to furnish the hydrogensul-
fate 1h (484 mg, 0.50 mmol, 100%) after evaporation of the solvent as a colorless
solid, mp. 126°C. IR (ATR): nu(tilde) = 3094 (w), 1750 (m), 1734 (m), 1461 (w), 1346
(m), 1320 (m), 1229 (vs), 1183 (vs), 1143 (vs), 1124 (vs), 1078 (s), 1041 (s), 1016
(m), 993 (m), 840 (m), 748 (m), 734 (m), 697 (s), 648 (s) cm–1. C24H15F26NO8S
(971.40): calcd. C 29.68%, H 1.56%, N 1.44%, S 3.30%; found C 29.64%, H 1.55%,
N 1.38%, S 3.04%.
1-Methyl-3,5-bis(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctanoyl)pyridinium
perfluorododecanoate (1j). A solution of compound 1b in MeOH obtained from iodo
compound 1a (4.00 g, 4.00 mmol) according to the General Procedure was neutra-
lized with perfluorododecanoic acid (2.46 g, 4.00 mmol) to furnish the compound 1j
(5.95 g, 4.00 mmol, 100%) after evaporation of the solvent as a colorless solid, mp.
81°C. IR (ATR): nu(tilde) = 1742 (m), 1685 (m), 1342 (m), 1191 (vs), 1142 (vs), 1080
(m), 1001 (w), 842 (w), 809 (w), 746 (m), 697 (s), 652 (s) cm–1. C36H14F49NO6
(1487.43): calcd. C 29.07%, H 0.95%, N 0.94%; found C 29.06%, H 0.84%, N 1.04%.
1-Ethyl-3,5-bis(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctanoyl)pyridinium iodide
(2a). A solution of EtI (5.0 mL, 9.7 g, 62 mmol, 11 equiv.) and pyridine dicarboxylate
5 (5.00 g, 5.82 mmol, 1.0 equiv.) in acetone (5 mL) was stirred in a tightly closed
reaction tube for 3 h at 150°C. After evaporation of the volatiles, the residue was re-
crystallized from MTBE (15 mL) to furnish the product 2a (4.36 g, 4.29 mmol, 74%)
1
as yellow solid, mp. 182°C. H-NMR (500 MHz, acetone-d6): δ = 1.81 (t, J = 7.4 Hz,
3H), 3.00 (tt, J = 19.3 Hz, J = 6.2 Hz, 4H), 4.87 (t, J = 6.0 Hz, 4H), 5.23 (q, J = 7.3
13
Hz, 2H), 9.36 (t, J = 1.6 Hz, 1H), 10.15 (d, J = 1.6 Hz, 2H) ppm. C{1H}-NMR (125
MHz, CD3OD): δ = 16.75 (CH3), 31.08 (t, J = 21.2 Hz, 2 CH2), 59.79 (CH2), 60.20 (2
CH2),132.39 (2 C), 145.67 (CH), 150.21 (2 CH), 161.76 (2 C) ppm. 19F-NMR (470
MHz, acetone-d6): δ = 50.63–50.86 (m, 4F), 53.41–53.61 (m, 4F), 54.02–54.21 (m,
4F), 55.00–55.26 (m, 4F), 63.46–63.48 (m, 4F), 95.78 (tt, J = 2.6 Hz, J = 10.4 Hz, 6F)
ppm. IR (ATR): nu(tilde) = 3016 (w), 2978 (w), 2937 (w), 1733 (s), 1335 (m), 1233
(s), 2281 (vs), 1141 (vs), 1077 (s), 842 (m), 811 (m), 739 (s), 697 (s) cm–1. HR-MS
(ESI, pos. mode): calcd. 888.0659 (for C25H16F26NO4), found 888.0698 [M+ – I].
C25H16F26INO4 (1015.27): calcd. C 29.58%, H 1.59%, N 1.38%; found C 29.69%, H
1.67%, N 1.57%.
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Single crystal X-ray data for 2a were measured on a Bruker AXS Apex II diffracto-
meter (Mo-Kα radiation, λ = 0.71073 Å, Kappa 4 circle goniometer, Bruker Apex II de-
tector) at T = 170 K. Compound 2a crystallizes in the monoclinic space group P21/n
with a = 7.5040(2), b = 47.8412(15), c = 9.6717(3) Å, β = 93.3645(15)°, V =
3466.16(18) Å3, Z = 4. A numerical absorption correction followed by a correction ba-
sed on symmetry-related measurements (multi-scan) was performed with
SADABS.[24] The structure was solved with the program SHELXS[25] and refined with
SHELXL.[25] Non-H atoms were refined anisotropically, non-H atoms involved in dis-
order were partially refined isotropically. H atoms were located from the difference
Fourier maps but subsequently fixed to geometric positions using appropriate riding
models. Refinement parameters: 90723 reflections measured, 7656 unique (Rint
=
0.0287), 6876 observed [I > 2sig(I)], R1 for the observed data = 0.0572, wR2 =
0.1362, R1 for all data = 0.0625, wR2 = 0.1390, GooF = 1.196, maximum and
minimum difference density = 0.939 and –1.855 e Å–1.
1-Ethyl-3,5-bis(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctanoyl)pyridinium
hydroxide (2b). Iodo compound 2a (507 mg, 0.50 mmol) was converted according to
the General Procedure to furnish compound 2b (456 mg, 0.50 mmol, 100%) after
evaporation of the solvent as a light yellow colorless solid, mp. 57°C. IR (ATR):
nu(tilde) = 3421 (w), 2974 (w), 1702 (m), 1678 (s), 1615 (m), 1541 (m), 1461 (m),
1358 (w), 1335 (m), 1321 (m), 1231 (s), 1202 (s), 1162 (s), 1122 (s), 1081 (s), 1035
(s), 1006 (m), 950 (w), 866 (m), 696 (m), 643 (m) cm–1. C25H17F26NO5 (905.37):
calcd. C 33.17%, H 1.89%, N 1.55%; found C 33.21%, H 2.07%, N 1.58%.
1-Ethyl-3,5-bis(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctanoyl)pyridinium acetate
(2c). A solution of compound 2b in MeOH obtained from iodo compound 2a (507 mg,
0.50 mmol) according to the General Procedure was neutralized with acetic acid (0.5
mL of a 1 mol L–1 solution in MeOH) to furnish acetate 2c (384 mg, 0.41 mmol, 81%)
after evaporation of the solvent and recrystallization from MTBE (20 mL) as a light
yellow colorless solid, mp. 132°C. IR (ATR): nu(tilde) = 3035 (w), 1965 (w), 1735 (s),
1650 (m), 1610 (m), 1450 (w), 1351 (m), 1311 (m), 1275 (m), 1234 (m), 1187 (s),
1142 (s), 1124 (s), 1078 (m), 841 (m), 651 (s) cm–1. C27H19F26NO6 (947.41): calcd. C
34.23%, H 2.02%, N 1.48%; found C 34.52%, H 2.36%, N 1.81%.
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1-Ethyl-3,5-bis(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctanoyl)pyridinium
tri-
fluoroacetate (2d). A solution of compound 2b in MeOH obtained from iodo com-
pound 2a (507 mg, 0.50 mmol) according to the General Procedure was neutralized
with trifluoroacetic acid (0.5 mL of a 1 mol L–1 solution in MeOH) to furnish trifluoro-
acetate 2d (410 mg, 0.42 mmol, 83%) after evaporation of the solvent and recrystalli-
zation from MTBE (10 mL) as a light yellow colorless solid, mp. 152°C. IR (ATR):
nu(tilde) = 3099 (w), 3056 (w), 3046 (w), 3022 (w), 1753 (m), 1739 (m), 1685 (m),
1343 (m), 1232 (m), 1188 (s), 1141 (vs), 1124 (s), 1078 (s), 746 (m), 697 (m), 651
(m) cm–1. C27H16F29NO6 (985.38): calcd. C 31.63%, H 1.43%, N 1.42%; found C
31.41%, H 1.45%, N 1.56%.
1-Ethyl-3,5-bis(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctanoyl)pyridinium
tri-
fluoromethanesulfonate (2e). A solution of compound 2b in MeOH obtained from
iodo compound 2a (507 mg, 0.50 mmol) according to the General Procedure was
neutralized with trifluoromethanesulfonic acid (0.5 mL of a 1 mol L–1 solution in
MeOH) to furnish triflate 2e (511 mg, 0.49 mmol, 99%) after evaporation of the
solvent as an orange solid, mp. 136°C. IR (ATR): nu(tilde) = 3084 (w), 3039 (w),
1741 (m), 1380 (w), 1342 (m), 1322 (w), 1258 (s), 1239 (s), 1178 (s), 1141 (vs), 1124
(s), 1079 (m), 1031 (m), 1005 (w), 842 (w), 747 (m), 697 (m), 638 (s) cm–1.
C26H16F29NO7S (1037.43): calcd. C 30.10%, H 1.35%, N 1.55%, S 3.09%; found C
30.13%, H 1.17%, N 1.51%, S 2.75%.
1-Ethyl-3,5-bis(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctanoyl)pyridinium bis(tri-
fluoromethanesulfonyl)amide (2f). A solution of compound 2b in MeOH obtained
from iodo compound 2a (507 mg, 0.50 mmol) according to the General Procedure
was neutralized with bis(trifluoromethanesulfonyl)imide (140 mg, 0.50 mmol) to
furnish the triflimide 2f (563 mg, 0.48 mmol, 96%) after evaporation of the solvent as
a colorless solid, mp. 51°C. IR (ATR): nu(tilde) = 3087 (w), 1746 (m), 1347 (m), 1234
(m), 1179 (vs), 1133 (s), 1055 (s), 740 (m), 652 (m), 618 (m) cm–1. C27H16F32N2O8S2
(1168.50): calcd. C 27.75%, H 1.38%, N 2.40%, S 5.49%; found C 27.41%, H 1.66%,
N 2.58%, S 5.10%.
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1-Ethyl-3,5-bis(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctanoyl)pyridinium chlori-
de (2g). A solution of compound 2b in MeOH obtained from iodo compound 2a (507
mg, 0.50 mmol) according to the General Procedure was neutralized with hydrochlo-
ric acid (0.5 mL of a 1 mol L–1 solution in MeOH containing some water) to furnish the
chloride 2g (461 mg, 0.50 mmol, 100%) after evaporation of the solvent as a yellow
solid, mp. 141°C. IR (ATR): nu(tilde) = 2897 (w), 1735 (s), 1646 (w), 1335 (m), 1234
(s), 1180 (vs), 1079 (s), 1050 (m), 1011 (m), 843 (w), 812 (w), 752 (m), 698 (m), 680
(m), 651 (m) cm–1. C25H16ClF26NO4 (923.82): calcd. C 32.50%, H 1.75%, N 1.52%;
found C 32.31%, H 2.12%, N 1.70%.
1-Ethyl-3,5-bis(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctanoyl)pyridinium
bro-
mide (2h). A solution of compound 2b in MeOH obtained from iodo compound 2a
(507 mg, 0.50 mmol) according to the General Procedure was neutralized with hydro-
bromic acid (0.5 mL of a 1 mol L–1 solution in MeOH containing some water) to fur-
nish the bromide 2h (484 mg, 0.50 mmol, 100%) after evaporation of the solvent as a
colorless solid, mp. 154°C. IR (ATR): nu(tilde) = 3102 (w), 2966 (w), 1748 (m), 1735
(m), 1333 (w), 1262 (m), 1174 (s), 1123 (s), 1076 (m), 1048 (m), 1007 (m), 749 (m),
695 (m), 649 (m) cm–1. C25H16BrF26NO4 (968.27): calcd. C 31.01%, H 1.67%, N
1.40%; found C 31.34%, H 1.97%, N 1.78%.
1-Ethyl-3,5-bis(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctanoyl)pyridinium
hydrogensulfate (2i). A solution of compound 2b in MeOH obtained from iodo com-
pound 2a (507 mg, 0.50 mmol) according to the General Procedure was neutralized
with sulfuric acid (0.5 mL of a 1 mol L–1 solution in MeOH) to furnish the hydrogensul-
fate 2h (487 mg, 0.49 mmol, 99%) after evaporation of the solvent as a light yellow
colorless solid, mp. 112°C. IR (ATR): nu(tilde) = 2989 (w), 1744 (m), 1232 (m), 1171
(s), 1140 (s), 1083 (s), 1006 (m), 890 (m), 812 (m), 745 (m), 698 (m), 648 (m) cm–1.
C25H17F26NO8S (985.43): calcd. C 30.47%, H 1.74%, N 1.42%, S 3.25%, found C
30.20%, H 1.90%, N 1.65%, S 3.45%.
1-Ethyl-3,5-bis(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctanoyl)pyridinium
perfluorododecanoate (2j). A solution of compound 2b in MeOH obtained from iodo
compound 2a (5.71 g, 5.62 mmol) according to the General Procedure was neutra-
lized with perfluorododecanoic acid (3.45 g, 5.62 mmol) to furnish the compound 2j
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10.1002/ejoc.201700717
European Journal of Organic Chemistry
(8.21 g, 5.47 mmol, 97%) after evaporation of the solvent as a colorless solid, mp.
59°C. IR (ATR): nu(tilde) = 1735 (w), 1690 (w), 1667 (w), 1393 (w), 1328 (w), 1214
(m), 1179 (vs), 1140 (s), 1077 (m), 811 (m), 750 (m), 698 (m), 678 (m), 652 (m) cm–1.
C37H16F49NO6 (1501.46): calcd. C 29.60%, H 1.07%, N 0.93%; found C 29.48%, H
1.38%, N 0.85%.
1,3-Bis(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl)imidazolium iodide (3a). A mix-
ture of perfluorinated iodoalkane 9 (5.21 g, 11.0 mmol, 2.20 equiv.) and imidazole
(340 mg, 5.00 mmol, 1.00 equiv.) in toluene (5 ml) was stirred in a tighly closed tube
at 110°C for 24 h. After evaporation of excess volatile materials, the mixture was dis-
solved in MTBE (20 mL) and washed with water (2 x 20 mL). The organic layer was
dried (MgSO4) and evaporated after filtration. The title compound 3a (1.86 g, 2.09
mmol, 44%) was obtained after recrystallization from EtOAc/hexane (1 / 10, 50 mL)
1
as a colorless solid, mp. >300°C. H-NMR (500 MHz, DMSO-d6): δ = 3.00 (tt, J =
19.2 Hz, J = 6.4 Hz, 4H), 4.61 (t, J = 6.5 Hz, 4 H), 7.93 (s, 2H), 9.40 (s, 1H) ppm.
13C{1H}-NMR (125 MHz, DMSO-d6): δ = 29.91 (2 CH2), 41.49 (2 CH2), 122.78 (2 CH),
137.36 (CH) ppm. 19F-NMR (470 MHz, DMSO-d6): δ = –80.50 (tt, J = 2.5 Hz, J = 9.6
Hz, 6F), (–113.16)–(–113.48) (m, 4F), (–121.73)–(–121.99) (m, 4F), (–122.59)–(–
122.92) (m, 4F), (–123.07)–(–123.31) (m, 4F), (–125.69)–(–126.16) (m, 4F) ppm. IR
(ATR): nu(tilde) = 3122 (w), 3055 (w), 1575 (m), 1321 (w), 1235 (s), 1180 (s), 1142
(s), 1121 (s), 1077 (s), 1040 (m), 743 (m), 691 (m), 632 (m), 616 (s) cm–1. HR-MS
+
(ESI, pos. mode): calcd. 761.0502 (for C19H11F26N2 ), found 761.0497 [M+ – I].
C19H11F26IN2 (888.17): calcd. C 25.69%, H 1.25%, N 3.15%; found C 25.93%, H
1.12%, N 3.55%.
1,3-Bis(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl)imidazolium hydroxide (3b).
Iodo compound 3a (888 mg, 1.00 mmol) was converted according to the General
Procedure to furnish compound 3b (778 mg, 1.00 mmol, 100%) after evaporation of
the solvent as a brown liquid. IR (ATR): nu(tilde) = 3106 (w), 1647 (w), 1570 (w),
1365 (w), 1321 (w), 1232 (s), 1187 (s), 1141 (vs), 1123 (s), 1077 (m), 735 (m), 700
(m), 644 (m) cm–1. C19H12F26N2O (778.28): calcd. C 29.32%, H 1.55%, N 3.60%;
found C 29.35%, H 1.25%, N 3.45%.
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1,3-Bis(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl)imidazolium acetate (3c). A so-
lution of compound 3b in MeOH obtained from iodo compound 3a (888 mg, 1.00
mmol) according to the General Procedure was neutralized with acetic acid (1.0 mL
of a 1 mol L–1 solution in MeOH) to furnish acetate 3c (820 mg, 1.00 mmol, 100%)
after evaporation of the solvent as a colorless liquid. IR (ATR): nu(tilde) = 3152 (w),
3106 (w), 3065 (w), 1711 (m), 1569 (w), 1412 (w), 1364 (w), 1232 (s), 1190 (s), 1122
(s), 1078 (m), 1008 (m), 708 (m), 700 (m), 647 (m) cm–1. C21H14F26N2O2 (820.32).
calcd. C 30.75%, H 1.75%, N 3.42%; found C 30.87%, H 1.74%, N 3.65%.
1,3-Bis(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl)imidazolium
trifluoroactate
(3d). A solution of compound 3b in MeOH obtained from iodo compound 3a (888 mg,
1.00 mmol) according to the General Procedure was neutralized with trifluoroacetic
acid (1.0 mL of a 1 mol L–1 solution in MeOH) to furnish trifluoroacetate 3d (849 mg,
0.99 mmol, 99%) after evaporation of the solvent as a colorless liquid. IR (ATR):
nu(tilde) = 3152 (w), 3097 (w), 3066 (w), 1779 (m), 1570 (w), 1166 (s), 1140 (s), 1078
(m), 809 (m), 706 (m) cm–1. C21H11F29N2O2 (858.28): calcd. C 29.39%, H 1.29%, N
3.26%; found C 28.99%, H 0.96%, N 3.38%.
1,3-Bis(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl)imidazolium trifluoromethane-
sulfonate (3e). Under exclusion of moisture (N2 atmosphere), a mixture of perfluori-
nated triflate 7 (2.50 g, 5.04 mmol, 2.5 equiv.) and trimethylsilylimidazole (280 mg,
2.02 mmol, 1.0 equiv.) was stirred for 24 h at 60°C. Subsequently, the mixture was
dissolved in MTBE (20 mL) and washed with water (2 x 20 mL). The organic layer
was dried (MgSO4) and evaporated after filtration. The title compound (651 mg, 0.720
mmol, 35%) was received after recrystallization from CH2Cl2 (50 mL) as a colorless
solid, mp. 163°C. IR (ATR): nu(tilde) = 3155 (w), 3124 (w), 3082 (w), 1573 (w), 1366
(w), 1321 (w), 1251 (s), 1226 (s), 1179 (s), 1142 (vs), 1125 (s), 1080 (m), 1029 (s),
995 (w), 848 (w), 747 (m), 636 (s) cm–1. C20H11F29N2O3S (910.33): calcd. C 26.39%,
H 1.22%, N 3.08%, S 3.52%; found C 26.53%, H 1.56%, N 3.30%, S 3.25%.
1,3-Bis(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl)imidazolium bis(trifluorome-
thanesulfonyl)amide (3f). A solution of compound 3b in MeOH obtained from iodo
compound 3a (888 mg, 1.00 mmol) according to the General Procedure was neutra-
lized with bis(trifluoromethanesulfonyl)imide (281 mg, 1.00 mmol) to furnish the trifle-
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10.1002/ejoc.201700717
European Journal of Organic Chemistry
mide 3f (1.02 g, 0.98 mmol, 98%) after evaporation of the solvent as a colorless
solid, mp. 54°C. IR (ATR): nu(tilde) = 3089 (w), 1683 (m), 1570 (w), 1350 (w), 1182
(s), 114 (vs), 1081 (m), 1055 (m), 701 (m), 641 (m), 617 (m) cm–1. C21H11F32N3O4S2
(1041.40): calcd. C 24.22%, H 1.06%, N 4.04%, S 6.16%; found C 24.18%, H 1.37%,
N 4.27%, S 6.48%.
1,3-Bis(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl)imidazolium chloride (3g). A
solution of compound 3b in MeOH obtained from iodo compound 3a (888 mg, 1.00
mmol) according to the General Procedure was neutralized with hydrochloric acid
(1.0 mL of a 1 mol L–1 solution in MeOH containing some water) to furnish the
chloride 3g (789 mg, 0.99 mmol, 99%) after evaporation of the solvent as a yellow
solid, mp. 172°C. IR (ATR): nu(tilde) = 3092 (w), 3064 (w), 3010 (w), 2990 (w), 1569
(w), 1365 (w), 1321 (w), 1231 (s), 1188 (s), 1168 (s), 1124 (s), 1075 (m), 840 (m),
699 (m), 643 (m) cm–1. C19H11ClF26N2 (796.72): calcd. C 28.64%, H 1.39%, N 3.52%;
found C 28.45%, H 1.29%, N 3.49%.
1,3-Bis(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl)imidazolium bromide (3h). A
solution of compound 3b in MeOH obtained from iodo compound 3a (888 mg, 1.00
mmol) according to the General Procedure was neutralized with hydrobromic acid
(1.0 mL of a 1 mol L–1 solution in MeOH containing some water) to furnish the
bromide 3h (790 mg, 0.96 mmol, 96%) after evaporation of the solvent as a colorless
solid, mp. 249°C. IR (ATR): nu(tilde) = 3063 (w), 2988 (w), 2964 (w), 1573 (w), 1366
(w), 1320 (w), 1232 (s), 1181 (s), 1141 (vs), 1122 (s), 1077 (m), 700 (m), 639 (m),
622 (m) cm–1. C19H11BrF26N2 (822.18): calcd. C 27.13%, H 1.32%, N 3.33%; found C
27.38%, H 1.05%, N 3.35%.
1,3-Bis(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl)imidazolium hydrogensulfate
(3i). A solution of compound 3b in MeOH obtained from iodo compound 3a (888 mg,
1.00 mmol) according to the General Procedure was neutralized with sulfuric acid
(1.0 mL of a 1 mol L–1 solution in MeOH) to furnish the hydrogensulfate 3h (863 mg,
1.00 mmol, 100%) after evaporation of the solvent as a colorless solid, mp. 83°C. IR
(ATR): nu(tilde) = 3308 (s), 3174 (m), 3121 (s), 2967 (m), 2754 (s), 2642 (s), 1919
(w), 1660 (w), 1595 (s), 1462 (m), 1316 (m), 1201 (w), 1050 (vs), 979 (vs), 901 (vs),
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10.1002/ejoc.201700717
European Journal of Organic Chemistry
901 (vs), 870 (vs), 798 (vs), 628 (vs) cm–1. C19H12F26N2O4S (858.33): calcd. C
26.59%, H 1.41%, N 3.26%, S 3.74%; found C 26.80%, H 1.61%, N 3.05%, S 3.92%.
1,3-Bis(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl)imidazolium
perfluorodode-
canoate (3j). A solution of compound 3b in MeOH obtained from iodo compound 3a
(500 mg, 0.56 mmol) according to the General Procedure was neutralized with perflu-
orododecanoic acid (346 mg, 0.56 mmol) to furnish the compound 3j (770 mg, 0.56
mmol, 100%) after evaporation of the solvent as a colorless solid, mp. 125°C. IR
(ATR): nu(tilde) = 3087 (w), 3063 (w), 2988 (w), 1682 (m), 1571 (w), 1367 (w), 1195
(s), 1142 (vs), 1080 (m), 709 (m), 643 (m) cm–1. C31H11F49N2O2 (1374.36): calcd. C
27.09%, H 0.81%, N 2.04%; found C 27.42%, H 0.63%, N 2.24%.
Acknowledgement
This work was funded by the "Zentrales Innovationsprogramm Mittelstand (ZIM)" of
the "Bundesministerium für Wirtschaft und Energie (BMWi)" (Germany). We are
grateful to Malena Hillje for experimental support and to Dr. Izabella Brand for helping
us with contact angle measurements. MTBE was obtained as a generous gift from
Evonik Industries, Marl, Germany.
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