Cobalt(II) Complexes of Ionic Liquids
FULL PAPER
moacetonitrile (11.99 g, 0.1 mol) were dissolved in toluene (100 mL) at
C
10
H
15
N
3
O
4
F
6
S
2
·H
2
O: C 27.46, H 3.91, N 9.61; found C 27.58, H 3.66, N
0
8C. The temperature was raised slowly to 608C within 1 h and the mix-
9.52.
-(3-Cyanopropyl)-1-methylpyrrolidinium
mide, [C [Tf N] (1C): [C
gously to [C [Tf N], starting from lithium bis(trifluoromethylsul-
ture was stirred for a further 24 h. A yellowish precipitate was filtered,
washed with diethyl ether, and subsequently dried under vacuum. Yield
1
1
bis(trifluoromethylsulfonyl)i-
[Tf N] was synthesized analo-
1
C
3CNPyr]
A
H
U
G
R
N
U
G
2
1
C
3CNPyr]
A
H
N
T
E
N
N
2
1
8.72 g (91%); m.p. 998C; H NMR ([D
6
]DMSO): d=5.17 (s, 2H), 3.69
]DMSO): d=112.79,
5.30, 50.95, 50.50, 21.98; elemental analysis calcd (%) for
Br·H O: C 37.68, H 6.78, N 12.56; found C 37.77, H 6.10, N
1
C1CNPyr]
A
H
U
G
R
N
U
G
2
1
3
(
m, 4H), 3.26 (s, 3H), 2.13 (m,4H); C NMR ([D
6
fonyl)imide (14.35 g, 0.05 mol) and 1-(3-cyanopropyl)-1-methylpyrrolidi-
6
C
1
nium bromide (11.60 g, 0.05 mol). Yield 15.456 g (71%); m.p.<RT;
H
13
N
2
2
1
7
H NMR ([D
t, 2H), 2.10 (m, 6H); C NMR ([D
113.41), 119.58, 64.09, 61.84, 47.87, 21.25, 19.80, 13.99; elemental analysis
6
]DMSO): d=3.55 (m, 2H), 3.40 (m, 4H), 3.00 (s, 3H), 2.58
2.84.
-(3-Cyanopropyl)-1-methylpyrrolidinium bromide, [C
3CNPyr][Br] was analogous to that of [C
13
(
6
]DMSO): d=(126.19, 121.93, 117.67,
1
1
C
3CNPyr][Br]: The
1CNPyr][Br],
synthesis of [C
1
C
1
C
17 3 4 6 2
calcd (%) for C11H N O F S : C 30.49, H 3.95, N 9.70; found C 30.12, H
starting from 1-methylpyrrolidine (8.52 g, 0.1 mol) and 4-bromobutaneni-
trile (14.801 g, 0.1 mol). Yield 17.402 g (75%); m.p. 1238C; H NMR
3.29, N 9.33.
1
1
-(5-Cyanopentyl)-1-methylpyrrolidinium
bis(trifluoromethylsulfonyl)i-
N] (1D): The synthesis of [C [Tf N] was
[Tf N], starting from lithium bis(trifluor-
(
2
2
6
[D ]DMSO): d=3.57 (m, 2H), 3.48 (m, 4H), 3.05 (s, 3H), 2.66 (t, 2H),
mide, [C
1
C
5CNPyr]
A
H
U
G
R
N
U
G
2
1
C
5CNPyr]
A
C
H
T
U
N
G
T
R
E
N
N
U
N
G
2
1
3
.05 (m, 6H); C NMR ([D
6
]DMSO): d=120.04, 65.30, 61.77, 48.07,
Br·0.5H O (%):
analogous to that of [C
omethylsulfonyl)imide (14.35 g, 0.05 mol) and 1-(5-cyanopentyl)-1-meth-
1
C
1CNPyr]
A
H
N
T
E
N
N
2
1.37, 19.87, 14.14; elemental analysis calcd for C
9
H
17
N
2
2
C 44.04, H 7.62, N 11.15; found C 44.42, H 7.61, N 11.17.
-(5-Cyanopentyl)-1-methylpyrrolidinium bromide, [C 5CNPyr][Br]: The
synthesis of [C 5CNPyr][Br] was analogous to that of [C 1CNPyr][Br],
ylpyrrolidinium bromide (13.01 g, 0.05 mol). Yield 15.79 g (68%); m.p.<
1
1
1
C
RT; H NMR ([D
6
]DMSO): d=3.42 (m, 4H), 3.28 (m, 2H), 2.96 (s,3H),
1
C
1
C
2.46 (m, 2H), 2.09 (m, 4H), 1.73 (m, 2H), 1.61 (m, 2H), 1.39 (m,2H);
1
3
starting from N-methylpyrrolidine (8.52 g, 0.1 mol) and 6-bromohexane-
C NMR ([D
63.21, 47.82, 25.15, 24.48, 22.47, 21.29, 16.17; elemental analysis calcd (%)
for C13 (%): C 33.84, H 4.59, N 9.11; found C 33.59, H 3.47,
N 8.80.
Cobalt(II) bis(trifluoromethylsulfonyl)imide: CoCl ·6H O (17.84 g,
6
]DMSO): d=(126.16, 121.90, 117.63, 113.37), 120.73, 63.86,
1
nitrile (17.61 g, 0.1 mol). Yield 22.93 g (88%); m.p. 468C; H NMR
(
2
(
1
8
[D
.04 (m, 4H), 1.70 (m, 2H), 1.57 (m, 2H), 1.33 (m, 2H); C NMR
[D ]DMSO): d=121.13, 63.74, 62.86, 47.90, 25.19, 24.54, 22.60, 21.36,
6.43; elemental analysis calcd (%) for C11 Br·0.5H O: C 48.31, H
.30, N 10.03; found C 49.16, H 8.66, N 10.08.
6
]DMSO): d=3.51 (m, 4H), 3.37 (m, 2H), 3.00 (s, 3H), 2.52 (m, 2H),
21 3 4 6 2
H N O F S
1
3
6
2
2
H
21
N
2
2
0.075 mol) was dissolved in water (25 mL) and NaOH solution was
added until the pH was alkaline. The precipitated Co(OH) ·6H O was fil-
2
2
Precursor 3-(pyrrolidin-1-yl)propanenitrile: 1-(2-Cyanoethyl)-1-methyl-
pyrrolidinium iodide, [C 2CNPyr][I], was synthesized by the reaction of
pyrrolidine with acrylonitrile, followed by quaternization with iodome-
thane. Direct quaternization with 3-bromopropanenitrile resulted in very
low yields owing to the formation of acrylonitrile. Pyrrolidine (9.00 g,
tered and washed thoroughly with water until the washing water was free
from chloride ions (tested with AgNO ). An excess of cobalt(II) hydrox-
ide (15.07 g, 0.075 mol) dispersed in water (25 mL) was added to an aque-
ous solution of HTf N (28.11 g, 0.10 mol). This mixture was warmed for
24 h to 808C under stirring in a vessel equipped with a reflux condenser.
The mixture was cooled to RT, then the remaining excess of cobalt(II)
hydroxide was filtered. The solution was evaporated by using a rotary
evaporator; the purple crystals were subsequently dried in vacuo. Yield
1
C
3
[
22]
2
1
27 mmol) was mixed with water (50 mL) and stirred at RT. Acrylonitrile
(
10.08 g, 190 mmol) was added dropwise. The solution became warm and
it was stirred for 2 h at room temperature (although the reaction was
exothermic, cooling was unnecessary). The product was extracted with
ethyl acetate from the aqueous phase, and the organic layer was dried on
90%; elemental analysis calcd (%) for Co(N
C 6.61, H 1.66, N 3.85; found C 6.82, H 1.51, N 3.77.
[C C Pyr] [Co(Tf N) ] (2): To obtain crystals of [C C Pyr] [Co
A
H
U
G
R
N
U
G
2
CF
3
)
2
)
2
A
H
N
T
E
U
(H
2
O)
6
(727.3):
Na
2
SO
4
. A pure colorless liquid was obtained after distillation. Yield
A
H
U
G
R
N
U
G
A
H
U
G
R
N
U
G
ACHTUNGTRENNUNG( Tf N) ],
1
4
2
2
4
1
4
2
2
4
9
0%; b.p. (2–3 mmHg) 578C.
2 2 2 1 4 2
Co ACHTUNRTGENNU(GN Tf N) ·6H O (3.64 g, 5 mmol) was dissolved in [C C Pyr] ACHTUNGTRENNUNG[ Tf N]
1
-(2-Cyanoethyl)-1-methylpyrrolidinium iodide, [C
1
C
2CNPyr][I]: 3-(Pyrro-
(16.86 g, 40 mmol). The solution was warmed to 1208C in vacuo in a
Schlenk flask and stirred for 4 h at this temperature. The dark purple so-
lution was then cooled to RT. The compound crystallized as purple plates
only after this solution had been cooled in a deep freezer to ꢀ228C for
24 h and subsequently left for three days at RT.
lidin-1-yl)propanenitrile (12.421 g, 0.1 mol) and iodomethane (14.194 g,
.1 mol) were dissolved in toluene (100 mL) at 08C. The temperature
0
was raised slowly to RT within 1 h and stirred for a further 4 h. A yellow-
ish precipitate was filtered and washed with diethyl ether and subse-
quently dried under vacuum. Yield 23.91 g (90%); m.p. 1248C; H NMR
1
1 2 4 2 2 2
[Co(C C1CNPyr)2 AHCTNUTGERNNUNG( Tf N) ] (3): Co CAHTUNGTNERNU(G Tf N) ·6H O (0.73 g, 1 mmol) was dis-
(
2
2
[D
6
]DMSO): d=3.74 (t, 2H), 3.53 (d, 4H), 3.23 (t, 2H), 3.06 (s, 3H),
1 2
solved in [C C1CNPyr] ACHTUNREGTNNUNG[ Tf N] (4.05 g, 10 mmol). The solution was warmed
1
3
.08 (d, 4H); C NMR ([D
1.37, 13.52; elemental analysis calcd (%) for C
6
]DMSO): d=118.24, 64.22, 57.83, 47.94,
I: C 36.11, H 5.68,
to 1208C in vacuo in a Schlenk flask and stirred for 4 h at this tempera-
ture. The dark purple solution was then cooled to RT. The compound
crystallized as pink plates only after this solution had been cooled in a
deep freezer to ꢀ228C for 24 h and subsequently left for three days at
RT. Compound 3 could also be obtained and crystallized by adding
8
15 2
H N
N 10.53; found C 36.14, H 5.58, N 10.30.
-Cyanomethyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide,
[Tf N] (1A): Lithium bis(trifluoromethylsulfonyl)imide
11.483 g, 0.04 mol) was dissolved in water (25 mL) and added dropwise
1CNPyr][Br] (8.205 g, 0.04 mol). The prod-
uct layer was separated from the aqueous phase and washed thoroughly
with water until the AgNO test confirmed the absence of remaining bro-
mide impurities. The product was then dried under vacuum. Yield
1
[
C
1
C
1CNPyr]
A
C
H
T
U
N
G
T
R
E
N
N
U
N
G
2
[
C
1
C1CNPyr]
A
H
U
G
R
N
U
G
2
N] (4.05 g, 10 mmol) to a dehydrated solution (treatment
(
1
to an aqueous solution of [C C
A
H
U
G
R
N
U
G
2
2
2
1
C
4
A
H
U
G
R
N
U
G
2
4
3
1
2 8 1 2 8
AHCTUNGTERNUNN[G Tf N] (4): [Co(C C2CNPyr)6] ACHTNUGTRUNNENG[ Tf N] crystals were ob-
1
1
0.930 g (67%); m.p. 78C; H NMR ([D
6
]DMSO): d=4.82 (s, 2H), 3.64
(s, 3H), 2.18 (m, 4H); C NMR ([D ]DMSO): d=(126.12,
21.87, 117.60, 113.34), 112.39, 65.38, 50.80, 50.34, 21.86; elemental analy-
tained by dissolving Co
2 2 2 1
ACHTNUGRTNNUGE( Tf N) ·6H O (0.73 g, 1 mmol) in [C C2CNPyr]-
1
3
(
m, 4H), 3.21
A
C
H
T
U
N
G
T
R
E
N
N
U
N
G
6
ACHTUNGTRENNUNG
[Tf N] (4.42 g, 10 mmol), warming the solution to 1208C in vacuo in a
2
1
Schlenk flask for 4 h, stirring it for 4 h at this temperature and then cool-
ing it to RT. Crystallization as orange block-like crystals from this orange
solution occurred only after it had been cooled to ꢀ228C for 24 h in a
deep freezer and subsequently left for three days at RT.
sis calcd (%) for C
H 3.43, N 10.51.
9 13 3 4 6 2
H N O F S : C 26.67, H 3.23, N 10.37; found C 26.53,
1
-(2-Cyanoethyl)-1-methylpyrrolidinium bis(trifluoromethylsulfonylimide,
[Tf N] (1B): [C [Tf N] was synthesized analogously
[Tf N], starting from lithium bis(trifluoromethylsulfonyl)-
[
C
1
C
2CNPyr]
A
C
H
T
U
N
G
T
R
E
N
N
U
N
G
2
1
C
2CNPyr]
A
H
U
G
R
N
N
2
to [C
1
C
1CNPyr]
A
C
H
T
U
N
G
T
R
E
N
N
U
N
G
2
imide (14.35 g, 0.05 mol) and 1-(2-cyanoethyl)-1-methylpyrrolidinium
1
iodide (13.31 g, 0,05 mol). Yield 15.54 g (74%); m.p.<RT; H NMR
(
2
6
[D ]DMSO): d=3.71 (t, 2H), 3.51 (d, 4H), 3.17 (t, 2H), 3.04 (s, 3H),
1
3
6
.11 (d, 4H); C NMR ([D ]DMSO): d=(126.13, 122.02, 117.67, 113.32),
1
18.00, 64.23, 57.99, 47.74, 21.26, 13.22; elemental analysis calcd (%) for
Chem. Eur. J. 2010, 16, 1849 – 1858
ꢄ 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
1857