Synthesis and characterization of light-fluorous NHC-ligands and their palladium complexes

Article abstract of DOI:10.1016/j.jorganchem.2020.121634

Light-fluorous ponytails containing perfluoro-n-propyl, perfluoro-n-butyl and perfluoro-t-butoxy groups were used to synthesize light-fluorous α-olefins, branched dialkyl iodides, alkyl triflates, alkyl imidazoles, and dialkyl imidazolium salts. The latte

Full text of DOI:10.1016/j.jorganchem.2020.121634

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Synthesis and characterization of light-fluorous NHC-ligands and
their palladium complexes
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Angel S.W. Lo , Ken S.M. Yiu , Istvan T. Horvath
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S0022-328X(20)30537-4
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https://doi.org/10.1016/j.jorganchem.2020.121634
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Please cite this article as: Angel S.W. Lo , Ken S.M. Yiu , Istvan T. Horvath , Synthesis and char-
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Synthesis and characterization of light-fluorous NHC-ligands
and their palladium complexes
Angel S.W. Lo,a Ken S. M. Yiua and István T. Horváth*,a,b
aDepartment of Chemistry, City University of Hong Kong, Kowloon, Hong Kong
bDepartment of Chemical and Environmental Process Engineering,
Budapest University of Technology and Economics, Budapest, Hungary
Email address of the corresponding author: istvan.t.horvath@edu.bme.hu
Highlights
 Light-fluorous olefins, iodides, and triflates containing n-C3F7, n-C4F9, and t-C4F9
groups were used to prepare light-fluorous alkyl imidazols and dialkyl imidazolium
salts.
 The partition coefficients of the light-fluorous olefins, iodides, and triflates were
measured in the perfluoro(methylcyclohexane)/toluene biphasic system.
 Two light-fluorous N,N’-dialkyl-imidazole-2-ylidene diiodo palladium(II) complexes
were prepared and structurally characterized.
Dedicated to Professor László Kollár on the occasion of his 65th birthday.
Abstract
Light-fluorous ponytails containing perfluoro-n-propyl, perfluoro-n-butyl and
perfluoro-t-butoxy groups were used to synthesize light-fluorous -olefins, branched
dialkyl iodides, alkyl triflates, alkyl imidazoles, and dialkyl imidazolium salts. The
latter were used to prepare two light-fluorous N,N’-dialkyl-imidazole-2-ylidene diiodo
palladium(II) complexes. The fluorous partition coefficients of the light-fluorous
olefins, iodides, and triflates were measured in perfluoro(methylcyclohexane)/toluene
biphasic system, which revealed that the shorter and environmentally friendlier
perfluoroalkyl chains of the light-fluorous ponytails results in lower fluorous partition
coefficients, especially as the number of methylene groups increases.
Graphical abstract
I-
2.5 eq. Cs2CO3
Pd(OOCCH )
+
+
3 2
THF, 65 oC
N
N
R
R
R = CH2CH2CF2CF2CF2CF3
Keywords
Perfluoroalkyl groups, light-fluorous olefins, light-fluorous dialkyl iodides, light
fluorous alkyl imidazols, light-fluorous dialkyl imidazolium salts, light-fluorous NHC
ligands and their palladium complexes.
1

1.
Introduction
N-heterocyclic carbenes (NHC) [1] can be used to replace carbonyl and
phosphine ligands in organometallic chemistry and transition metal homogenous
catalysis [2]. Fluorous NHC ligands [3] have been also developed to facilitate
catalyst recycling and product(s) separation by using the fluorous biphasic concept
(Scheme 1) [4]. In general, linear fluorous ponytails consisting of C6-10-perfluoroalkyl
chains and methylene spacers in appropriate number are attached to the N-atoms to
achieve high fluorous partition and lower the strong electron-withdrawing effect of the
perfluoroalkyl chains [4, 5].
Several fluorous NHC complexes of silver, ruthenium, and palladium have been
synthesized and some of them successfully used in catalytic reactions including
cyclization of diene, ring closing metathesis, Heck and Suzuki coupling, Mizoroki-
Heck reactions, and Suzuki-Miyaura cross-coupling [1, 2].
The accidental release of fluorous compounds to the environment could
result in light-assisted oxidation/hydrolysis of the hydrocarbon domain to form the
corresponding perfluoroalkyl carboxylic acids (PFCAs), some of which are persistent,
easily bioaccumulate, have long half-lives in human and animal species, and some
of them are toxic [6].
Perfluorooctanoic acid (C7F15COOH, PFOA) is perhaps the best known and most
studied PFCA. The health and ecologicals risks of perfluoroalkyl compounds have
been also assessed [7, 8, 9, 10, 11, 12, 13].
The bioaccumulation and the cytotoxicity of perfluoroalkyl compounds have
been shown to correlate with the length of the perfluoroalkyl chain [14, 15, 16, 17,
18]. Therefore, the replacement of long perfluoroalkyl chains with shorter ones was
proposed to lower the toxicity with respect to PFOA and limit bioaccumulation [19].
2

For example, the perfluoro-tert-butyl group has been used to prepare fluorous
compounds which could provide high fluorous solubility and minimise the adverse
health and environmental effects [20]. To aid the further development of sustainable
fluorous chemistry, we report the synthesis of novel fluorous olefins and iodides with
perfluoro-tert-butoxy ponytails as well as novel alky imidazoles, dialkyl imidazolium
salts and their palladium complexes, bearing shorter perfluoropropyl (C3F7-) and
perfluorobutyl (C4F9-) groups.
2.
Results and Discussions
Fluorous olefins 1a-c were prepared by the reaction of the corresponding
tosylates with sodium perfluoro-tert-butoxide in DMSO in good to high yields
(Scheme 1). The starting precursor sodium perfluoro-tert-butoxide can be easily
prepared from commercially available sodium perfluoro-tert-butanol by the reported
literature procedure [20a].
CH
(CH2)n
CH2
CH2
TsO
CF3
n = 1 - 3
(CH2)n
CH
DMSO
80oC
+
+
CH2
NaOTs
C
O
CH2
CF3
CF3
CF3
-
1a (n =1, 71.8%)
1b (n =2, 85.3%)
1c (n =3, 62.2%)
+
C
Na
O
CF3
CF3
Scheme 1. Synthesis of fluorous olefins 1a – c.
One of the possible applications of fluorous -olefins is their radical reaction
with perfluoroalkyl iodides to form the corresponding secondary fluorous iodides. The
radical addition of perfluoro-n-butyl iodide to fluorous olefins 1a-c in the presence of
AIBN resulted in the formation of the corresponding branched fluorous iodides 2a-c
in moderate yields, which were isolated by fluorous extraction with
perfluoro(methylcyclohexane) (Scheme 2).
3

CF3
(CH2)n
CH
CF2
CF2
CH2
C
O
+
I
CH2
CF2
CF3
CF3
CF3
1a (n =1), 1b (n =2), 1c (n =3)
80oC
AIBN
I
CF3
(CH2)n
CH
CF2
CF2
CF2
CF3
C
O
CH2
CH2
CF3
CF3
2a (n =1, 80.8%)
2b (n =2, 71.4%)
2c (n =3, 45.0%)
Scheme 2. Synthesis of fluorous iodides 2a – c.
The synthesis of fluorous imidazoles and imidazolium salts by the reaction of
imidazole with perfluoroalkyl iodide or triflate has been demonstrated [3a,d ]. The
used fluorous triflates 3a-c were prepared from commercially available fluorous
alcohols and triflic anhydride by published procedures with minor modifications in
work-up (Scheme 3) [21].
Scheme 3. Synthesis of fluorous triflates 3a-c.
Fluorous triflates 3a and 3c were employed to prepare fluorous imidazoles 4a and 4c
in good yields (Scheme 4). Commercially available 1,1,1,2,2,3,3-heptafluoro-5-iodo-
pentane and 1,1,1,2,2,3,3,4,4-nonafluoro-6-hexyl iodide were used to prepare
imidazole 4b and 4d. However, their reactivity were significantly lower than the
similar reaction of imidazole and long-chain perfluorinated iodides [3]. Furthermore,
approximately 20% of di-substituted imidazolium salts were formed as the by-
product.
Scheme 4. Synthesis of fluorous imidazoles 4a-d.
4

The partition coefficients of fluorous olefins 1a-c, iodides 2a-c, triflates 3a-c
were measured by dissolving a given compound in a fluorous biphasic system
consisting of 2 mL perfluoro-(methylcyclohexane) and 2 mL toluene in a vial. The
mixture was shaken vigorously for 3 minutes and kept in a 25C water bath for 12
hours. The concentration of the given fluorous compound in the upper toluene-rich
phase and the lower fluorous phase was established by 19F NMR analysis (Table 1).
The partition coefficients of fluorous imidazoles 4a-d and imidazolium salts 5a-f in
the toluene/perfluoro-(methylcyclohexane) solvents system are excluded as they
could readily form insoluble materials. The formation of aggregates could be due to
the intermolecular hydrogen bonding with nitrogen atoms [22, 23]. The fluorous
partition coefficient (PF) of the tested compounds ranged from 0.10 to 4.59 by
increasing fluorine content from 35.4% to 59.7%. It appears that the addition of
methylene spacers and/or functional groups to a compound while keeping the
perfluoroalkyl chain the same could cause dramatic change of PF, fluorous olefins
1a-c, and triflates 3a-c are in line with this trend. As illustrated in Table 1, the PF of
2a resulted in higher fluorous partition than that of 2b-c. Similar observation was
made for perfluoro-tert-butoxy diethers [20b], where the fluorous groups could
aggregate or form a fluorous blanket to shield the hydrocarbon domain and limit the
attractive interactions with the organic solvent.
Table 1. The fluorous partition coefficients (PF) of some compounds in fluorous
biphasic systems comprised of perfluoro(methylcyclohexane) and toluene.
Fluorine content Fluorous Partition
Compounda
(%)
Coefficient (PF)b
1a
1b
1c
2a
2b
2c
3a
3b
3c
58.93
56.22
53.7
53.8
52.6
51.5
57.2
52.8
59.7
1.98
1.22
0.76
3.00
2.15
1.93
3.15
0.65
4.59
a 0.04-0.1 mmol of given compound was applied in biphasic solvent system.
bPF = the ratio of the equilibrium molar concentrations of the dissolved compound in the fluorous and
the organic phases (PF=cfluorous/corganic) measured by 19F NMR.
Fluorous imidazolium salts 5a-f were prepared by further alkylation with
fluorous triflate or iodide of fluorous imidazoles 4a-d to yield di-substituted
5

imidazolium salts (Scheme 5). Symmetric imidazolium salts 5a-d were yellow solid,
and asymmetric imidazolium salts, which R1 and R2 have different fluorous ponytails,
were viscous oil. Crystals of 5a, 5c and 5d were obtained by vapor diffusion of
acetone/n-hexane and their molecular structure were confirmed by X-ray diffraction
characterisation. The imidazolium ring of the molecule’s cation and ionic domains,
i.e. iodide and triflate, appear well resolved, the perfluorinated part encountered
greater anisotropy and disorders towards the end of the chain. Similar observations
were reported for fluorous pyridinium ionic liquids [24]. All crystal structures and their
crystallography data are available in supplementary document [25].
Scheme 5. Synthesis of imidazolium salts 5a-f.
Unfortunately, the reaction of fluorous secondary iodides 2a-c and imidazole
resulted in the elimination of HI and the formation of fluorous internal alkenes,
probably due to the insufficient insulation of the electron-withdrawing effect of the n-
C4F9-group [26].
Nitrogen heterocyclic carbene (NHC) metal complexes can be easily
prepared by the direct reaction of the imidazolium salts with metal compounds or
traditionally by substitution reactions with free carbenes via deprotonation of
corresponding imidazolium salts. The N-N’-disubstituted imidazole-2-ylidene
palladium complexes 6a and 6b have been prepared by reacting palladium acetate
with 2 equivalents of imidazolium salts 5b and 5d, respectively, in toluene for 2
hours. These complexes were both air- and water-stable and isolated as crystalline
solids in good yields (Scheme 6).
6

+
Pd
+
N
N
N
N
R
R
R
R
I-
2.5 eq. Cs2CO3
THF, 65 oC
I
I
Pd(OOCCH )
2 Cs(OOCCH3)
+
+
+
3 2
N
N
R
R
5b (R = C3F7CH2CH2)
5d (R = C4F9CH2CH2)
6a (R = C3F7CH2CH2, 85.1%)
6b (R = C4F9CH2CH2, 91.8%)
Scheme 6. Synthesis of fluorous palladium complexes 6a-b.
Single crystals of complexes 6a and 6b were obtained by vapor diffusion of
their solution in n-hexane:CH2Cl2(20:1) v/v%. X-ray crystal structural determination
revealed the expected square-planar geometry of the palladium atom and trans-
coordination of the two fluorous NHC ligands as well as the two iodides [27]. The
palladium-carbon bond lengths of 2.018(9)Å for 6a and 2.025(5)° for 6b, respectively
(Figure 1 and 2), are comparable with values found for similar palladium complexes
in the literature [3a,28,29].
Figure 1. ORTEP crystal structure of 6a with partial atomic numberings, being omitted for clarity.
Figure 2. ORTEP crystal structure of 6b with partial atomic numberings, being omitted for clarity.
7

3. Conclusions
Light-fluorous ponytails containing perfluoro-t-butoxy groups were used to
synthesize light-fluorous olefins (1a-c), branched dialkyl iodides (2a-c), and alkyl
triflates (3a-c). The fluorous partition coefficients of the light-fluorous olefins, iodides,
and triflates were measured in perfluoro(methylcyclohexane)/toluene biphasic
system, which revealed that the shorter and environmentally friendlier perfluoroalkyl
chains of the light-fluorous ponytails results in lower fluorous partition coefficients,
especially as the number of methylene groups increases. Light-fluorous ponytails
with perfluoro-n-propyl and perfluoro-n-butyl groups were used to prepare alkyl
imidazols (4a-d) and dialkyl imidazolium salts (5a-f). Two light-fluorous N,N’-dialkyl-
imidazole-2-ylidene diiodo palladium(II) complexes (6a-b) were also isolated and
structurally characterized – they exhibit the expected square-planar geometry of the
palladium atom and trans-coordination of the two fluorous NHC ligands as well as
the two iodides.
4. Experimental
4.1 Chemicals and General Procedures.
Perfluoro-tert-butanol,
perfluoro(methyl-cyclohexane),
2,2,3,3,4,4,4-hepta-
fluoro-1-butanol and 1,1,1,2,2,3,3-hepta-fluoro-5-iodopentane were products of
FluoroChem. 1,1,1,2,2,3,3,4,4-nonafluoro-6-hexyl iodide was purchased from TCI.
All purchased chemicals and solvents were used as received. Ethyl Acetate, toluene,
acetonitrile and tetrahydrofuran were products of RCI LabScan., dried over calcium
hydride and distilled prior to use. Sodium perfluoro-tert-butoxide was synthesized
according to a literature method in 100% yield [30]. 1H-, 13C-, 19F-NMR spectra were
recorded on a Bruker 300 MHz ASCEND AVANCE III HD or Bruker 400 MHz
AVANCE III or Bruker 600MHz ASCEND AVANCE III HD FT-NMR spectrometer at
room temperature. Data were expressed as chemical shifts in ppm, relative to TMS
13
(1H NMR δ = 0.00 ppm, C{1H} NMR δ = 0.00 ppm), residual chloroform (1H-NMR δ
= 7.26 ppm, 13C{1H} NMR δ = 77.2 ppm), d6-acetone (1H-NMR δ = 2.05 ppm, 13C{1H}
19
NMR δ = 29.84 ppm) or an internal standard for F (hexafluorobenzene δ = -164.9
ppm). Infrared spectra were recorded in the range of 600-4000 cm-1 using a Nujol
matrix or KBr plates on a Thermo Fisher Model Nicolet iS50 FTIR spectrometer. X-
8

Ray crystallography of single crystal was recorded by Oxford Diffraction Gemini S
Ultra diffractometer.
4.2
Synthesis and Characterization
4.2.1. But-3-en-1-yl 4-methylbenzenesulfonate
A solution of 3-buten-1-ol (10.20 g, 0.141 mol) in distilled pyridine (30 mL,
0.372 mol) in a round bottom flask was cooled with an ice-bath and then p-
toluenesulfonate chloride (22.58 g, 0.118 mol) was added. After stirring the mixture
at 0°C for 4 hours, iced water/concentrated HCl (45 mL, 4:1 v/v) was added to the
mixture. 90 mL diethyl ether was added and the organic upper phase was separated.
The organic phase was dried over anhydrous MgSO4. The mixture was filtered and
the diethyl ether was removed by rotary evaporator. The product was purified by
silica column chromatography, using n-hexane/ethyl acetate (4:1, v/v) eluent to
obtain a colourless liquid (20.44 g, 90.3 mmol, 76.5%). 1H NMR (600 MHz, δ in TMS):
2.40 (qt, 2H, J = 6.7 Hz, CHCH2), 2.46 (s, 3H, Me), 4.06 (t, 2H, J = 6.7 Hz, CH2OTs),
5.07 (m, 2H, CH=CH2), 5.67 (ddt, 1H, J = 17.1, 10.3, 6.7 Hz, CH=CH2), 7.35 (d, 2H,
13
J = 8.0Hz, 3,3’-Ar), 7.79 (d, 2H, J = 8.0 Hz, 2,2’-Ar); C{1H} NMR (151 MHz, δ in
TMS): 21.6 (s, Me), 33.1 (s, =CHCH2), 69.4 (s, CH2OTs), 118.1 (s, CH=CH2), 127.9
(s, 2,2’-Ar), 129.8 (s, 3,3’-Ar), 132.3 (s, CH=CH2), 133.2 (s, 4-Ar), 144.7 (s, 1-Ar).
4.2.2. Pen-4-en-1-yl 4-methylbenzenesulfonate
A solution of 4-penten-1-ol (8.53 g, 0.99 mol) in distilled pyridine (20 mL,
0.248 mol) in a round bottom flask was cooled with an ice-bath and then p-
toluenesulfonate chloride (17.17 g, 0.090 mol) was added. After stirring the mixture
at 0°C for 4 hours, iced water/concentrated HCl (45 mL, 4:1 v/v) was added to the
mixture. 90 mL diethyl ether was added and the organic upper phase was separated.
The organic phase was dried over anhydrous MgSO4. The mixture was filtered and
the diethyl ether was removed by rotary evaporator. The product was purified by
silica column chromatography, using n-hexane/ethyl acetate (4:1, v/v) eluent to
obtain a colourless liquid (14.47 g, 60.1 mmol, 66.9%). 1H NMR (600 MHz, δ in TMS):
1.74 (dq, 2H, J = 8.3, 6.5 Hz, CH2CH2OTs), 2.08 (tdd, 2H, 7.9, 6.1, 1.4 Hz, =CHCH2),
2.45 (s, 3H, Me), 4.04 (t, 2H, J = 6.4 Hz, CH2OTs), 4.96 (m, 2H, CH=CH2), 5.69 (ddt,
1H, J = 16.2, 11.1, 6.7 Hz, CH=CH2), 7.35 (d, 2H, J = 8.0 Hz, 3,3’-Ar), 7.79 (d, 2H, J
= 8.0 Hz, 2,2’-Ar); 13C{1H} NMR (151 MHz, δ in TMS): 21.6 (s, Me), 28.0 (s,
9

CH2CH2OTs), 29.4 (s, =CHCH2), 69.8 (s, CH2OTs), 115.8 (s, CH=CH2), 127.9 (s,
2,2’-Ar), 129.8 (s, 3,3’-Ar), 133.2 (s, 4-Ar), 136.6 (s, CH=CH2), 144.7 (s, 1-Ar).
4.2.3. Hex-5-en-1-yl 4-methylbenzenesulfonate
A solution of 5-hexen-1-ol (12.51 g, 0.125 mmol) in distilled pyridine (20 mL,
0.248 mol) in a round bottom flask was cooled with an ice-bath and then p-
toluenesulfonate chloride (21.65 g, 0.114 mol) was added. After stirring the mixture
at 0°C for 4 hours, iced water/concentrated HCl (45 mL, 4:1 v/v) was added to the
mixture. 90 mL diethyl ether was added and the organic upper phase was separated.
The organic phase was dried over anhydrous MgSO4. The mixture was filtered and
the diethyl ether was removed by rotary evaporator. The product was purified by
silica column chromatography, using n-hexane/ethyl acetate (4:1, v/v) eluent to
obtain a colourless liquid (19.22 g, 75.6 mmol, 66.3%). 1H NMR (600 MHz, δ in
TMS): 1.41 (tt, 2H, J = 9.6, 6.6 Hz, CH2CH2OTs), 1.65 (m, 2H, =CHCH2CH2), 2.00
(qd, 2H, 7.3, 1.4 Hz, =CHCH2), 2.45 (s, 3H, Me), 4.03 (t, 2H, J = 6.5 Hz, CH2OTs),
4.95 (m, 2H, CH=CH2), 5.72 (ddt, 1H, J = 16.9, 10.1, 6.7 Hz, CH=CH2), 7.34 (d, 2H,
13
J = 8.1 Hz, 3,3’-Ar), 7.79 (d, 2H, J = 8.2 Hz, 2,2’-Ar); C{1H} NMR (151 MHz, δ in
NMR): 21.6 (s, Me), 24.8 (s, =CHCH2CH2), 28.2 (s, CH2CH2OTs), 32.9 (s, =CHCH2),
70.4 (s, CH2OTs), 115.1 (s, CH=CH2), 127.9 (s, 2,2’-Ar), 129.8 (s, 3,3’-Ar), 133.3 (s,
4-Ar), 137.9 (s, CH=CH2), 144.7 (s, 1-Ar).
4.2.4 Nonafluoro-t-butoxy-1-butene (1a)
The sodium salt of perfluoro-t-butoxide (10.77 g, 41.7 mmol) was dissolved
in DMSO (10 mL) in a round bottom flask. But-3-en-1-yl 4-methylbenzenesulfonate
(10.38 g, 45.9 mmol) was added and the reaction mixture was stirred at 80 °C for 15
hours. The round bottom flask was cooled to room temperature, and water (30 mL)
was added to the reaction mixture and the lower fluorous liquid phase was extracted.
The fluorous phase was then washed with water (3 x 10 mL) and 1M sodium
hydroxide solution (3 x 10 mL). The product was isolated by vacuum transfer to
obtain a colourless liquid (8.69 g, 30.0 mmol, 71.8%). 1H NMR (600 MHz, δ in TMS):
2.43 (qt, 2H, J = 6.7, 1.3 Hz, =CHCH2), 4.04 (t, 2H, J = 6.6 Hz, OCH2), 5.13 (m, 2H,
CH=CH2), 5.79 (ddt, 1H, J = 17.1, 10.3, 6.8 Hz, CH=CH2). 13C{1H} NMR (151 MHz, δ
in TMS): 34.1 (s, =CHCH2), 69.1(s, CH2OTs), 80.0 (m, J = 29.6, 59.3 Hz, (CF3)3C),
1
19
117.9 (s, CH=CH2), 120.5 (m, JC–F = 292 Hz, CF3), 131.6 (s, CH=CH2); F NMR
10

(282 MHz, δ in CDCl3, C6F6 capillary): −68.79 (s, 9F, CF3). IR (neat):  3096 (w),
3012 (w, br), 2982 (w, br), 1649 (m), 1485 (m), 1253 (s), 1164 (s), 1015 (s).
4.2.5 Nonafluoro-t-butoxy-1-pentene (1b)
The sodium salt of perfluoro-t-butoxide (9.85 g, 38.2mmol) was dissolved in
DMSO (10 mL) in a round bottom flask. Pen-4-en-1-yl 4-methylbenzenesulfonate
(10.10 g, 42.0 mmol) was added and the reaction mixture was stirred at 80 °C for 15
hours. The round bottom flask was cooled to room temperature, and water (30 mL)
was added to the reaction mixture and the lower fluorous liquid phase was
extracted. The fluorous phase was further washed with water (3 x 10 mL) and 1M
sodium hydroxide solution (3 x 10 mL). The crude product was isolated by vacuum
transfer to obtain a colourless liquid (9.45 g, 31.1 mmol, 81.4%). 1H NMR (600 MHz,
δ in TMS): 1.79 (quint, 2H, J= 6.8 Hz, CH2CH2OTs), 2.16 (q, 2H, J= 6.7 Hz,
=CHCH2), 4.02 (t, 2H, J= 6.2 Hz, CH2OTs), 5.03 (m, 2H, CH=CH2), 5.79 (ddt, 1H, J=
16.9, 10.2, 6.7 Hz, CH=CH2). 13C{1H} NMR (151 MHz, δ in TMS): 29.0 (s, =CHCH2),
29.4 (s, CH2CH2OTs), 69.1(s, CH2OTs), 80.0 (m, J = 29.5, 59.2 Hz, (CF3)3C), 115.7
1
(s, CH=CH2), 119.9 (m, JC–F = 292 Hz, CF3), 137.1 (s, CH=CH2); 19F NMR (282
MHz, δ in CDCl3, C6F6 capillary): −68.81 (s, 9F, CF3). IR (neat):  2992 (w, br),
2934 (w, br), 2857 (w, br), 1647 (m), 1483 (m), 1270 (s), 1162 (s), 1011 (s).
4.2.6. Nonafluoro-t-butoxy-1-hexene (1c)
The sodium salt of perfluoro-t-butoxide (8.02 g, 31.1 mmol) was dissolved in
DMSO (10 mL) in a round bottom flask. Hex-5-en-1-yl 4-methylbenzenesulfonate
(11.84 g, 46.6 mmol) was added and the reaction mixture was stirred at 80 °C for 15
hours. The round bottom flask was cooled to room temperature, and ice-cold water
(30 mL) was added to the reaction mixture and the lower fluorous liquid phase was
extracted. The fluorous phase was further washed with ice-cold water (3 x 10 mL)
and 1M sodium hydroxide solution (3 x 10 mL). The crude product was purified by
vacuum transfer at 0°C to obtain a colourless liquid product (6.08 g, 19.1 mmol,
1
61.4%). H NMR (600 MHz, δ in TMS): 1.49 (m, 2H, CH2CH2OTs), 1.69 (m, 2H,
CH2CH2CH2OTs), 2.09 (m, 2H, =CHCH2), 4.01 (t, 2H, J = 6.7 Hz, CH2OTs), 4.99 (m,
13
2H, CH=CH2), 5.79 (ddt, 1H, J = 17.0, 10.2, 6.7 Hz, CH=CH2). C{1H} NMR (151
MHz, δ in TMS): 24.6 (s, CH2CH2CH2OTs), 29.1 (s, CH2CH2OTs), 33.1 (s, =CHCH2),
11

69.1(s, CH2OTs), 80.0 (m, J = 29.6, 58.9 Hz, (CF3)3C), 114.9 (s, CH=CH2), 119.9 (m,
1JC–F = 292 Hz, CF3), 138.1 (s, CH=CH2); 19F NMR(282 MHz, δ in CDCl3, C6F6
capillary): −68.97 (s, 9F, CF3). IR (neat):  3012, 1650 (w), 1486 (w), 1283 (s), 1252
(s), 1160 (s), 1007 (s).
4.2.7. 1-(Nonafluoro-tert-butoxy)-3-iodo-4-perfluorobutyl-butane (2a)
Compound 1a (3.38 g, 11.6 mmol) and perfluoro-n-butyl iodide (4.25 g, 12.3
mmol) were added to the 10 mL pressure tube, and recrystallised AIBN (10 mol%)
was added every 2 hours for 4 times, then the mixture was heated in 80°C oil bath
for 15 hours. Perfluoro(methylcyclohexane) (10 mL) and methanol (10 mL) was
added to the mixture, the lower fluorous phase was extracted. Solvent was removed
1
by rotary evaporator to obtain a yellow oil (5.98 g, 9.40 mmol, 80.8%). H NMR
(600MHz, δ in CDCl3): 2.21 (m, 2H, (CF3)3COCH2CH2), 2.92 (m, 2H, CH2C4F9), 4.22
13
(m, 2H, (CF3)3COCH2), 4.46 (tdd, 1H, CHICH2C4F9); C{1H} NMR (151 MHz, δ in
CDCl3): 14.24 (s, CHI), 40.23 (s, (CF3)3COCH2CH2), 41.94 (t, CH2C4F9), 69.56 (s,
(CF3)3COCH2), 79,86 (m, (CF3)3CO, J = 29.7, 59.6 Hz), 108.70 (m, CF2CF2CF2CF3),
110.33 (m, CF2CF2CF2CF3), 117.74 (m, CF2CF2CF2CF3 and CF2CF2CF2CF3),
120.42 (q, CF3, 1JC-F = 293.3 Hz); 19F NMR (δ in CDCl3 and C6F6): -73.5 (s, (CF3)3), -
84.2 (t, CF2CF2CF2CF3), -116.6 (m, CF2CF2CF2CF3), -127.7 (m, CF2CF2CF2CF3), -
129.1 (m, CF2CF2CF2CF3). IR (neat):  1477 (w), 1354 (m), 1285 (s), 1252(s), 1160
(s), 1136 (s), 1017 (s).
4.2.8. 1-(Nonafluoro-tert-butoxy)-4-iodo-5-perfluorobutyl-pentane (2b)
Compound 1b (1.33 g, 4.36 mmol) and perfluoro-n-butyl iodide (1.71 g, 4.94
mmol) were added to the 10 mL pressure tube, and recrystallised AIBN (10 mol%)
was added every 2 hours for 4 times, then the mixture was heated in 80°C oil bath
for 15 hours. Perfluoro(methylcyclohexane) (10 mL) and methanol (10 mL) was
added to the mixture, the lower fluorous phase was extracted. Solvent was removed
1
by rotary evaporator to obtain a yellow oil (2.02 g, 3.11 mmol, 71.4%). H NMR
(600MHz, δ in CDCl3): 1.92 (m, 4H, (CF3)3COCH2CH2CH2), 2.86 (m, 2H, CH2C4F9),
4.07 (t, 2H, (CF3)3COCH2), 4.35 (tdd, 1H, CHICH2C4F9); 13C{1H} NMR (151 MHz, δ in
CDCl3): 19.3 (s, CHI), 30.1 (s, (CF3)3COCH2CH2), 36.3 (s, (CF3)3COCH2CH2CH2),
41.9 (t, CH2C4F9), 68.6 (s, (CF3)3COCH2), 80.0 (m, (CF3)3CO, J = 29.5, 59.1 Hz),
12

108.6 (m, CF2CF2CF2CF3), 110.3 (m, CF2CF2CF2CF3), 117.6 (m, CF2CF2CF2CF3
1
and CF2CF2CF2CF3), 120.5 (q, CF3, JC-F = 293.7 Hz); 19F NMR (δ in CDCl3 and
C6F6): -73.56 (s, (CF3)3), -84.20 (t, CF2CF2CF2CF3), -117.43 (m, CF2CF2CF2CF3), -
127.68 (m, CF2CF2CF2CF3), -129.07 (m, CF2CF2CF2CF3). IR (neat):  1358(m), 1285
(s), 1250 (s), 1160 (s), 1138 (s), 1026 (s).
4.2.9. 1-(Nonafluoro-tert-butoxy)-5-iodo-6-perfluorobutyl-hexane (2c)
Compound 1c (1.29 g, 4.06 mmol) and perfluoro-n-butyl iodide (1.61 g, 4.65
mmol) were added to the 10 mL pressure tube, and recrystallised AIBN (10 mol%)
was added every 2 hours for 4 times, then the mixture was heated in 80°C oil bath
for 15 hours. Perfluoro(methylcyclohexane) (10 mL) and methanol (10 mL) was
added to the mixture, the lower fluorous phase was extracted. Solvent was removed
1
by rotary evaporator to obtain a yellow oil (1.22 g, 1.84 mmol, 45.0%). H NMR
(600MHz, δ in CDCl3): 1.79 (m, 6H, (CF3)3COCH2CH2CH2CH2), 2.88 (m, 2H,
CH2C4F9), 4.07 (t, 2H, (CF3)3COCH2), 4.35 (tdd, 1H, CHICH2C4F9); 13C{1H} NMR
(151 MHz, δ in TMS): 19.8 (s, CHI), 25.6 (s, (CF3)3COCH2CH2CH2), 28.7 (s,
(CF3)3COCH2CH2), 39.7 (s, (CF3)3COCH2CH2CH2CH2), 41.8 (s, CH2C4F9), 69.4 (s,
(CF3)3COCH2), 79.9 (m, (CF3)3CO, J = 29.4, 59.7 Hz), 108.6 (m, CF2CF2CF2CF3),
110.3 (m, CF2CF2CF2CF3), 117.6 (m, CF2CF2CF2CF3 and CF2CF2CF2CF3), 120.6 (q,
CF3, 1JC-F = 292.7 Hz); 19F NMR (δ in CDCl3 and C6F6): -73.42 (s, (CF3)3), -84.12 (tt,
CF2CF2CF2CF3), -116.67 (m, CF2CF2CF2CF3), -127.59 (m, CF2CF2CF2CF3), -128.93
(m, CF2CF2CF2CF3). IR (neat):  1354(m), 1284 (s), 1250 (s), 1162 (s), 1135 (s),
1024 (s).
4.2.10. 1,1,1,2,2,3,3-Heptafluoro-4-butyl triflate (3a)
A sample of,2,2,3,3,4,4,4-Heptafluoro-1-butanol (4.0 g, 20 mmol), distilled
pyridine (1.8 mL, 22 mmol) and dichloromethane (10 mL) were added to 25 mL 2-
neck round bottom flask in ice-bath under N2 atmosphere. The mixture was stirred in
ice-bath for 30 mins. Triflic anhydride (3.75 mL, 22 mmol) in dichloromethane (3 mL)
was added dropwise to the mixture in ice-bath. After the addition of triflic anhydride,
the mixture was continued to stir at room temperature for 18 h. The crude product
was purified by flash alumina column, eluted with dichloromethane. The product was
dried over anhydrous MgSO4, filtered and solvent removed by rotary evaporator to
13

1
yield a colourless liquid (4.29 g, 12.9 mmol, 64.5%). H NMR (600MHz, δ in TMS):
4.82 (t, 2H, J = 12.2 Hz, CH2Im); 13C{1H} NMR (151 MHz, δ in (CD3)2CO): 68.0 (t, J =
28.3 Hz, CH2), 108.5 (tq, CF2CF2CF3), 112.5 (tt, CF2CF2CF3), 117.4 (qt, CF2CF2CF3),
118.6 (q, 1JC-F = 286.4 Hz, -CF3); 19F NMR (282MHz, δ in CDCl3 and C6F6): -77.08 (s,
CF3), -83.83 (t, CF2CF2CF3), -123.86 (m, CF2CF2CF3), -130.34 (m, CF2CF2CF3). ). IR
(neat):  1434 (s), 1358 (m), 1304 (m), 1231 (s), 1145 (s), 1035 (s), 1007 (s).
4.2.11. 1,1,1,2,2,3,3-Heptafluoro-6-hexyl triflate (3b)
A sample of 4,4,5,5,6,6,6,-Heptafluorohexan-1-ol (0.895 g, 3.92 mmol),
distilled pyridine (1.8 mL, 22 mmol) and dichloromethane (10 mL) were added to 25
mL 2-neck round bottom flask in ice-bath under N2 atmosphere. The mixture was
stirred in ice-bath for 30 mins. Triflic anhydride (3.75 mL, 22 mmol) in
dichloromethane (3 mL) was added dropwise to the mixture in ice-bath. After the
addition of triflic anhydride, the mixture was continued to stir at room temperature for
18 h. The crude product was purified by flash alumina column, eluted with DCM. The
product was dried over anhydrous MgSO4, filtered and solvent removed by rotary
1
evaporator to yield a colourless liquid (0.841 g, 2.34 mmol, 59.6%). H NMR (600
MHz, δ in TMS): 2.27-2.49 (m, 4H, C3F7CH2CH2), 4.65 (t, 2H, CH2OTf); 13C{1H} NMR
(151 MHz, δ in (CD3)2CO): 21.8 (t, CH2CH2OTf), 27.3 (t, C3F7CH2), 49.5 (s, CH2OTf),
108.5 (m, CF2CF2CF3), 112.5 (m, CF2CF2CF3), 117.4 (m, CF2CF2CF3), 118.6 (q, 1JC-
F = 286.5 Hz, -CF3); 19F NMR (282MHz, δ in CDCl3 and C6F6): -77.74 (s, -SO2CF3), -
83.69 (t, CF3), -118.48 (m, CF2CH2), -130.87 (m, CF3CF2). ). IR (neat):  1431 (s),
1308 (m), 1231 (s), 1142 (s), 1024 (s).
4.2.12. 1,1,1,2,2,3,3,4,4-Nonafluoro-5-pentyl triflate (3c)
A sample of,2,2,3,3,4,4,5,5,5-Nonafluoro-1-pentan-1-ol (1.345 g, 5.38 mmol),
distilled pyridine (0.48 mL, 5.91 mmol) and dichloromethane (10 mL) were added to
25 mL 2-neck round bottom flask in ice-bath under N2 atmosphere. The mixture was
stirred in ice-bath for 30 mins. Triflic anhydride (1.00 mL, 5.91 mmol) in
dichloromethane (3 mL) was added dropwise to the mixture in ice-bath. After the
addition of triflic anhydride, the mixture was continued to stir at room temperature for
12 h. The crude product was purified by flash alumina column, eluted with
dichloromethane. The product was dried over anhydrous MsgSO4, filtered and
14

solvent removed by rotary evaporator to yield a colourless liquid (0.897 g, 2.26 mmol,
42%). 1H NMR (300 MHz, δ in TMS): 4.85 (t, 2H, CH2OTf); 13C{1H} NMR (151 MHz,
δ in TMS): 68.0 (t, CH2OTf), 108.6 (m, CF2CF2CF3), 110.3 (m, CF2CF2CF3), 117.6 (m,
CH2CF3 & CF2CF2CF3), 118.5 (q, 1JC-F = 319.7 Hz, SO2CF3), ; 19F NMR (282 MHz, δ
in CDCl3 and C6F6): -77.0 (s, -SO2CF3), -83.90 (t, CF3), -122.96 (t, CF2CH2), -126.91
(m, CF3CF2), -129.22 (m, CF3CF2CF2). ). IR (neat):  1418 (s), 1360 (m), 1302 (m,
br), 1225 (s), 1147 (s), 1121 (m), 1033 (w).
4.2.13. 1-(1,1,1,2,2,3,3-Heptafluoro-4-butyl) imidazole (4a)
Under N2 atmosphere, triflate 3a (1.975 g, 5.95 mmol) was added to a 25 mL
Schlenk flask. Imidazole (1.215 g, 17.8 mmol) in acetonitrile (10 mL) was added
dropwise at room temperature. The mixture was stirred and heated in 80oC oil bath
for 15 hrs. The solvent was removed by reduced pressure, followed by the addition
of ethyl acetate (10 mL) and water (10 mL). The organic phase was separated and
dried over anhydrous Mg2SO4 and filtered. The solvent was removed by rotary
evaporator to obtain a yellow viscous liquid (0.833 g, 3.33 mmol, 56%).1H NMR
(600MHz, δ in TMS): 4.58 (t, 2H, CH2Im), 7.01 (s, 1H, C4-Im), 7.15 (s, 1H, C5-Im),
2
7.56 (s, 1H, C2-Im); 13C{1H} NMR (151 MHz, δ in CDCl3): 46.3 (t, JHF = 24 Hz,
CH2Im), 108.8 (m, CF2CF2CF3), 113.6 (m, CF2CF2CF3), 116.5 (m, CF2CF2CF3),
19
118.4 (m, CF3), 120.5 (s, C5-Im), 130.4 (s, C4-Im), 138.5 (s, C2-Im); F NMR (282
MHz, δ in CDCl3 and C6F6): -83.70 (t, CF3), -123.67 (m, CF2CH2), -130.46 (m,
CF3CF2). IR (nujol):  3371 (br), 1512 (m), 1229 (s), 1188 (s), 1115 (s).
4.2.14. 1-(1,1,1,2,2,3,3-Heptafluoro-5-pentyl) imidazole (4b)
Under N2 atmosphere, 1,1,1,2,2,3,3-Heptafluoro-5-iodopentane (1.979 g,
6.11 mmol) in acetonitrile (5 mL) was added in 25 mL schlenk tube. Imidazole (1.264
g, 18.6 mmol) in acetonitrile (5 mL) was added dropwise to the tube at room
temperature. The mixture was stirred and heated at 80oC for 24 h. Solvent removed
by reduced pressure. Dark yellow crude product was purified by silica column
chromatography, eluted with DCM/MeOH (10:1 v/v), to yield a yellow oil (0.259 g,
0.981 mmol, 16 %). 1H NMR (600MHz, δ in TMS): 2.58 (m, 2H, CH2CH2Im), 4.58 (t,
15

2H, 3JHF = 8 Hz, CH2Im), 7.01 (s, 1H, C4-Im), 7.15 (s, 1H, C5-Im), 7.56 (s, 1H, C2-Im);
13C{1H} NMR (151 MHz, δ in CDCl3): 32.8 (t, 2JCF = 22 Hz, CH2CH2Im), 38.9 (t, 3JCF =
5 Hz, CH2Im), 118.7 (s, C5-Im), 130.3 (s, C4-Im), 137.2 (s, C2-Im); 19F NMR (282MHz,
δ in CDCl3 and C6F6): -83.59 (t, JFF = 10 Hz, CF3), -118.42 (m, 2F), -130.88 (m, 2F).
IR (nujol):  3379 (br), 1511 (m), 1360(m), 1289 (m), 1235 (s), 1136 (s), 1110 (s),
1082 (s), 1011 (m).
4.2.15. 1-(1,1,1,2,2,3,3,4,4-Nonafluoro-5-pentyl) imidazole (4c)
In glove box, a 15 mL pressure tube was charged with triflate 3c (0.593 g,
1.50 mmol), imidazole (0.317 g, 4.65 mmol) in ethyl acetate (10 mL). The pressure
tube was closed and heated at 80oC oil bath for 24 h. White solid was formed. Crude
product was purified by silica column chromatography, eluted with DCM/MeOH (10:1
v/v) to yield a yellow oil (0.224 g, 0.746 mmol, 50%). 1H NMR (600 MHz, δ in TMS):
3
4.60 (t, JHF = 15 Hz, CH2Im), 7.01 (s, 1H, C4-Im), 7.14 (s, 1H, C5-Im), 7.56 (s, 1H,
13
2
C2-Im). C{1H}-NMR (151 MHz, δ in TMS): 46.4 (t, JCF = 24 Hz, CH2Im), 120.6 (s,
C5-Im), 130.3 (s, C4-Im), 138.6 (s, C2-Im); 19F NMR (282MHz, δ in CDCl3 and C6F6): -
83.98 (t, JFF = 10 Hz, CF3), -120.77 (m, 2F), -126.99 (m, 2F), -129.05 (m, 2F)). IR
(nujol):  3372 (br), 1654 (w, br), 1507 (m), 1362 (m), 1293 (m), 1238 (s), 1140 (s),
1117 (m), 1082 (m), 1030 (m).
4.2.16. 1-(1,1,1,2,2,3,3,4,4-Nonafluoro-6-hexyl) imidazole (4d)
In glovebox, 1,1,1,2,2,3,3,4,4-nonafluoro-6-hexyl iodide (2.012 g, 5.38 mmol)
and imidazole (1.178 g, 17.3 mmol) in toluene (10 mL) was added to 25 mL schlenk
tube. The mixture was stirred and heated at 80oC for 24 h. Solvent removed by
reduced pressure. Dark yellow crude product was purified by silica column
chromatography, eluted with DCM/MeOH (10:1, v/v), to yield a yellow oil (0.784 g,
3
2.50 mmol, 46%). 1H NMR (600 MHz, δ in TMS): 2.62 (tt, 2H, JHF = 18 Hz, 3JHH = 8
3
Hz, CH2CH2Im), 4.48 (t, 2H, JHH = 8 Hz, CH2Im), 6.97 (s, C5-Im), 7.13 (s, C4-Im),
7.55 (s, C2-Im); 13C{1H} NMR (151 MHz, δ in TMS): 33.2 (t, 2JCF = 22 Hz, CH2CH2Im),
39.0 (t, 3JCF = 6 Hz, CH2Im), 118.7 (s, C5-Im), 130.6 (s, C4-Im), 137.3 (s, C2-Im); 19F
NMR (375 MHz, δ in CDCl3 and C6F6): --84.15 (t, JFF = 10 Hz, CF3), -117.68 (m, 2F),
-127.57 (m, 2F), -129.18 (m, 2F). ). IR (nujol):  3371 (br), 1511 (m), 1358 (m), 1235
(s), 1184 (s), 1121 (s), 1082 (m), 1031 (m).
16

4.2.17. 1,3-Bis(1,1,1,2,2,3,3-heptafluoro-4-butyl)imidazolium triflate (5a)
Under N2 atmosphere, triflate 3a, (0.311 g, 0.936 mmol) in acetonitrile (2 mL)
was added to imidazole 4a (0.134 g, 0.533 mmol) in acetonitrile (3 mL) in 25 mL
schlenk flask. The mixture was stirred and heated at 80oC oil bath for 80 h. Solvent
removed under reduced pressure, precipitated in CHCl3 (10 mL). Crude product was
filtered and recovered in acetone (10 mL). Solvent removed by rotary evaporator to
yield white solid. Product was recrystallised in n-hexane/ethyl acetate (20:1, v/v)
(90.7 mg, 0.156 mmol, 29%). 1H NMR (600 MHz, δ in (CD3)2CO): 5.72 (t, 4H, 3JHF
=
3
16 Hz, CH2), 8.22 (d, 2H, JHH = 2 Hz, C4- and C5-proton Im), 9.83 (s, 1H, C2-proton
13
2
Im); C{1H} NMR (151 MHz, δ in (CD3)2CO): 49.1 (t, JCF = 22 Hz, CH2), 121.0 (q,
1JCF = 321 Hz, CF3), 126.2 (s, C4 and C5-Im), 141.9 (s, C2-Im); 19F NMR (282 MHz, δ
in (CD3)2CO and C6F6): -79.41 (s, CF3), -81.80 (t, JFF = 10 Hz, CF3), -118.92 (m, 2F),
-128.08 (m, 2F). ). IR (KBr):  3451 (w, br), 3128 (w, br), 1628 (w, br), 1574 (w),
1357 (m), 1279 (s), 1249 (s), 1226 (s), 1192 (m), 1129 (m), 1033 (m).
C12H7F17N2O3S Calc. C 24.75, H 1.21, N 4.81; CHN analysis, C 24.96, H 1.193, N
4.91.
4.2.18. 1,3-Bis(1,1,1,2,2,3,3-heptafluoro-5-pentyl)imidazolium iodide (5b)
Under N2 atmosphere, 1,1,1,2,2,3,3-Heptafluoro-5-iodopentane (0.485 g, 1.5
mmol) and imidazole 4b (0.264 g, 1 mmol) in toluene (7 mL) were added into 10 mL
pressure tube. The mixture was stirred and heated at 110oC for 144 h. The mixture
was filtered and the solid recovered by dissolving in acetone. Solvent was removed
by rotary evaporator to yield yellow solid (0.308 g, 0.524 mmol, 52%). 1H NMR (600
3
MHz, δ in (CD3)2CO): 3.21 (m, 4H, CH2C4F9), 4.92 (t, 2H, JHF = 7 Hz), 8.11 (d, 2H,
13
3JHH = 2 Hz, C4- and C5-proton Im), 9.97 (s, 1H, C2-proton Im); C{1H} NMR (151
2
3
MHz, δ in (CD3)2CO): 31.8 (t, JCF = 22 Hz, CH2), 43.1 (t, JCF = 5 Hz), 124.0 (s, C4
and C5-Im), 139.1 (s, C2-Im); 19F NMR (282 MHz, δ in (CD3)2CO and C6F6): -81.66 (t,
JFF = 10 Hz, CF3), -115.64 (m, 2F), -128.88 (m, 2F). IR (KBr):  3455 (w, br), 3053 (w,
br), 1626 (w, br), 1574 (w), 1355 (m), 1227 (s), 1174 (s), 1119 (s), 1045 (w), 1026
(w).
4.2.19. 1,3-Bis(1,1,1,2,2,3,3,4,4-nonafluoro-5-pentyl) imidazolium triflate (5c)
17

In glovebox, a 25 mL pressure tube was charged with triflate 3c (0.223 g,
0.583 mmol) and imidazole 4c (0.159 g, 0.530 mmol) in toluene (5 mL). The tube
was sealed and heated in 110oC oil bath for 130 h. Crude product white solid was
formed and filtered off. The crude product was further washed with toluene (3 x 10
mL) and filtered. Solvent was removed in vacuo to yield white solid (0.108 g, 0.158
mmol, 29.8%). 1H NMR (600 MHz, δ in (CD3)2CO): 5.67 (t, 4H, 3JHF = 16 Hz, CH2Im),
13
8.16 (d, 2H, 3JHH = 2 Hz, C4- and C5-proton Im), 9.80 (s, 1H, C2-proton Im); C{1H}-
1
NMR (151 MHz, δ in (CD3)2CO): 46.9 (t, CH2Im), 119.5 (q, JCF = 320 Hz, CF3),
123.9 (s, C4 and C5-Im), 139.1 (s, C2-Im). 19F NMR (282MHz, δ in (CD3)2CO and
C6F6): -79.34 (s, CF3), -82.08 (t, JFF = 10 Hz, CF3), -118.16 (m, 2F), -124.54 (m, 2F),
-127.05 (m, 2F). IR (KBr):  3451 (w, br), 3047 (w, br), 1603 (w, br), 1571 (w), 1360
(m), 1258 (s), 1227 (s), 1172 (m), 1137 (s), 1031 (m).
4.2.20. 1,3-Bis(1,1,1,2,2,3,3,4,4-nonafluoro-6-hexyl)imidazolium iodide (5d)
Under N2 atmosphere, 1,1,1,2,2,3,3,4,4-nonafluoro-6-hexyl iodide (0.561 g,
1.5 mmol) and imidazole 4d (0.314 g, 1 mmol) in toluene (8 mL) were added into 25
mL schlenk tube, the mixture was stirred and heated at 110oC for 200 h. White solid
suspended in the solution and filtered off by canular filtration. The crude product was
washed with toluene (3 x 10 mL), solvent was filtered off again. Residual solvent was
1
removed in vacuo to yield yellow solid (0.337 g, 0.490 mmol, 49.0%). H NMR
3
(600MHz, δ in CD3CN): 2.89 (m, 4H, CH2C4F9), 4.59 (t, 4H, JHH = 3 Hz, CH2Im),
3
13
7.60 (d, 2H, JHH = 2 Hz, C4- and C5-proton Im), 9.05 (s, 1H, C2-proton Im); C{1H}
NMR (151 MHz, δ in CD3CN): 31.9 (t, 2JCF = 22 Hz, CH2), 43.1 (t, 3JCF = 5 Hz), 124.1
19
(s, C4 and C5-Im), 138.1 (s, C2-Im); F NMR (δ in CD3CN and C6F6): -82.28 (tt, 3JFF
4
= 10 Hz, JFF = 3 Hz, CF3), -115.07 (m, 2F), -125.48 (m, 2F), -127.04 (m, 2F). IR
(KBr):  3454 (w, br), 3047 (w, br), 1615 (w, br), 1570 (w), 1357 (m), 1225 (s), 1134
(s), 1014 (m).
4.2.21. 1-(1,1,1,2,2,3,3-Heptafluorobutyl)-3-(1,1,1,2,2,3,3,4,4-nonafluoro-6-hexyl)
imidazolium triflate (5e)
Under N2 atmosphere, triflate 3a (0.273 g, 0.822 mmol) and imidazole 4d
(0.257 g, 0.818 mmol) in toluene (8 mL) were added into 25 mL schlenk tube. The
mixture was stirred and heat at 110oC for 200 h. Yellow oily solid was formed and
18

filtered off by canular filtration. The crude product was washed with toluene (3 x 10
mL) and the solvent was filtered off again. Residual solvent was removed in vacuo to
1
yield brown oil (0.125 g, 0.190 mmol, 23.6%). H NMR (600 MHz, δ in (CD3)2CO):
3
3
3
3.18 (tt, 4H, JHH = 7 Hz, JHF = 19 Hz, CH2C4F9), 4.95 (t, 4H, JHH = 7 Hz,
CH2CH2C4F9), 5.58 (t, 4H, 3JHF = 16 Hz), 8.04 (s, C5-Im), 8.15 (s, C4-Im), 9.61 (s, C2-
Im); 13C{1H} NMR (151 MHz, δ in (CD3)2CO): 31.0 (t, 2JCF = 21 Hz, CH2C4F9), 43.0 (t,
2
1
3JCF = 5 Hz, CH2CH2C4F9), 48.2 (t, JCF = 22 Hz, CH2C3F7), 121.6 (q, JCF = 321 Hz,
19
SO2CF3), 124.2 (s, C5-Im), 125.3 (s, C4-Im), 139.9 (s, C2-Im); F NMR (282 MHz, δ
in (CD3)2CO) and C6F6): -79.42 (s, CF3), -81.89 (t, JFF = 10 Hz, Heptafluoro-CF3), -
82.28 (t, JFF = 10 Hz, Nonafluoro-CF3), -115.03 (m, 2F), -119.11 (m, 2F), -125.42 (m,
2F), -127.05 (m, 2F), -128.22 (m, 2F).
4.2.22. 1-(1,1,1,2,2,3,3-Heptafluoropentyl)-3-(1,1,1,2,2,3,3,4,4-nonafluoro-6-hexyl)
imidazolium iodide (5f)
Under N2 atmosphere, imidazole (4b, 0.117 g, 0.442 mmol) and
1,1,1,2,2,3,3,4,4-nonafluoro-6-hexyl iodide (0.182 g, 0.486 mmol) in toluene (10 mL)
were added into 15 mL pressure tube, the mixture was stirred and heated at 110oC
for 72 h. Yellow oily solid was suspended in the solution and filtered off by canular
filtration. The crude product was washed with toluene (3 x 10 mL) and the solvent
was filtered off again. Residual solvent was removed in vacuo to yield brown oil
1
(0.107 g, 0.168 mmol, 38%). H NMR (600 MHz, δ in (CD3)2CO): 3.20 (m, 4H,
3
CH2CF2), 4.91 (2 sets of t, 4H, JHF = 7 Hz, CH2Im), 8.13 (s, C4 and C5-Im), 9.95 (s,
2
C2-Im); 13C{1H} NMR (151 MHz, δ in (CD3)2CO): 31.5 (2 sets of t, JCF = 21 Hz,
CH2CF2), 42.7 (t, 3JCF = 5 Hz, CH2CH2CF2), 123.7 (s, C4 and C5-Im), 138.7 (s, C2-Im);
19F NMR (282 MHz, δ in (CD3)2CO) and C6F6): -81.71 (t, JFF = 10 Hz, Heptafluoro-
CF3), -82.22 (t, JFF = 10 Hz, Nonafluoro-CF3), -114.87 (m, 2F), -115.66 (m, 2F), -
125.42 (m, 2F), -125.23 (m, 2F), -126.96 (m, 2F), -128.76 (m, 2F).
4.2.23. Bis-[1,3-bis(1,1,1,2,2,3,3-Heptafluoro-5-pentyl)imidazol-2-ylidene]
diiodo-
palladium(II) (6a)
Under N2 atmosphere, compound 5b (0.111 g, 0.189 mmol), Pd(OAc)2
(0.0202 g, 0.0898 mmol) and Cs2CO3 (0.0760 g, 0.233 mmol) in THF (10 mL) were
stirred and heated at 65oC, in 25 mL schlenk tube for 15 h. The mixture was filtered
19

through a pad of alumina. Solvent removed and dried by rotary evaporator to yield
1
yellow solid (0.0986 g, 0.0769 mmol, 85.1%). H NMR (600MHz, δ in d-acetone):
3
3
3.13 (m, 4H, JHH = 8 Hz, JHF = 19 Hz, CH2C3F7), 4.85 (t, 4H, 3JHF = 8 Hz), 7.54 (s,
2H, C4- and C5-proton Im); 13C{1H} NMR (151 MHz, δ in (CD3)2CO): 31.9 (t, 2JCF = 22
Hz, CH2C3F7), 43.6 (t, 3JCF = 4 Hz, CH2Im), 123.6 (s, C4 and C5-Im), 169.0 (s, C2-Im);
19F NMR (376 MHz, δ in (CD3)2CO and C6F6): -81.67 (t, JFF = 10 Hz, CF3), -115.67
(m, 2F), -128.88 (m, 2F). IR (KBr):  3448 (w, br), 3120 (w, br), 1355 (m), 1222 (s),
1177 (s), 1115 (s). C26H22F28I2N4Pd Calc. C 24.35, H 1.73, N 4.37; CHN analysis, C
25.51, H 1.77, N 3.82.
4.2.24. Bis-[1,3-bis(1,1,1,2,2,3,3,4,4-nonafluoro-6-hexyl)imidazol-2-ylidene]
diiodo
palladium(II) (6b)
Under N2 atmosphere, compound 5d (0.131 g, 0.190 mmol), Pd(OAc)2
(0.0203 g, 0.0906 mmol) and Cs2CO3 (0.0738 g, 0.226 mmol) in THF (15 mL) were
stirred and heated at 65oC, in 25 mL schlenk tube for 15 h. The mixture was filtered
through a pad of alumina. Solvent removed and dried by rotary evaporator to yield
1
yellow solid (0.123 g, 0.0830 mmol, 91.8%). H NMR (600MHz, δ in (CD3)2CO): 3.15
3
3
3
(m, 4H, JHH = 8 Hz, JHF = 19 Hz, CH2C4F9), 4.87 (t, 4H, JHF = 8 Hz), 7.56 (s, 2H,
C4- and C5-proton Im); 13C{1H} NMR (151 MHz, δ in (CD3)2CO): 31.9 (t, 2JCF = 22 Hz,
3
CH2C3F7), 43.4 (t, JCF = 4 Hz, CH2Im), 123.5 (s, C4 and C5-Im), 168.72 (s, C2-Im);
19F NMR (376 MHz, δ in (CD3)2CO and C6F6): -82.30 (t, JFF = 10 Hz, CF3), -114.91(m,
2F), -125.34 (m, 2F), -127.02 (m, 2F). IR (KBr):  3448 (w, br), 3103 (w, br), 1355
(m), 1227 (s), 1134 (s). C30H22F36I2N4Pd Calc. C 24.30, H 1.50, N 3.78; CHN
analysis, C 25.11, H 1.83, N 4.52.
4.3
Example of partition coefficient measurement
An 8 mL vial was charged with 2a (0.0254 g, 0.04 mmol) and
perfluoro(methylcyclohexane) (CF3C6F11, 2.00 mL). Toluene (2.00 mL) was added
and the mixture was vigorously shaken for 2 minutes. The vial was kept at 25°C for
12 hours. The aliquots (each phase 0.5 mL) were taken from both phases. The
internal standard hexafluorobenzene (C6F6) was added to above aliquots (CF3C6F11:
0.8674 g solution; 0.010 g, 0.0052 mmol C6F6; toluene: 0.4468 g solution; 0.009 g,
0.0048mmol C6F6). Then put in d6-DMSO capillary and the sample was analysed by
20

19F NMR (integration of CF3 signal against C6F6). The procedure was triplicate and
applied 2.0/0.5 scale factor gives an average partition coefficient of 25:75, a total
mass recovery of 96%).
Acknowledgements
This work was funded by the City University of Hong Kong and the Innovation
and Technology Support Programme of the Innovation and Technology Fund of the
Government of the Hong Kong SAR (ITS/161/18).
Any opinions, findings,
conclusions or recommendations expressed in this material/event (or by members of
the project team) do not reflect the views of the Government of the Hong Kong
Special Administrative Region, the Innovation and Technology Commission or the
Panel of Assessors for the Innovation and Technology Support Programme of the
Innovation and Technology Fund.
Appendix A. Supplementary data
Supplementary data related to this article can be found at ….
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Declaration of interests
☒ The authors declare that they have no known competing financial interests or
personal relationships that could have appeared to influence the work reported in this paper.
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