Highly Efficient Carbon Monoxide Capture by Carbanion-Functionalized Ionic Liquids through C-Site Interactions

Article abstract of DOI:10.1002/anie.201701919

A novel method for the highly efficient and reversible capture of CO in carbanion-functionalized ionic liquids (ILs) by a C-site interaction is reported. Because of its supernucleophilicity, the carbanion in ILs could absorb CO efficiently. As a result, a relatively high absorption capacity for CO (up to 0.046 mol mol^?1) was achieved under ambient conditions, compared with CO solubility in a commonly used IL [Bmim][Tf₂N] (2×10^?3 mol mol^?1). The results of quantum mechanical calculations and spectroscopic investigation confirmed that the chemical interaction between the C-site in the carbanion and CO resulted in the superior CO absorption capacities. Furthermore, the subsequent conversion of captured CO into valuable chemicals with good reactivity was also realized through the alkoxycarbonylation reaction under mild conditions. Highly efficient CO absorption by carbanion-functionalized ILs provides a new way of separating and converting CO.

Full text of DOI:10.1002/anie.201701919

Angewandte
Communications
Chemie
International Edition: DOI: 10.1002/anie.201701919
German Edition: DOI: 10.1002/ange.201701919
CO Capture
Highly Efficient Carbon Monoxide Capture by Carbanion-
Functionalized Ionic Liquids through C-site Interactions
Duan-Jian Tao,* Feng-Feng Chen, Zi-Qi Tian, Kuan Huang, Shannon M. Mahurin,
De-en Jiang,* and Sheng Dai*
Abstract: A novel method for the highly efficient and
reversible capture of CO in carbanion-functionalized ionic
liquids (ILs) by a C-site interaction is reported. Because of its
supernucleophilicity, the carbanion in ILs could absorb CO
efficiently. As a result, a relatively high absorption capacity for
CO (up to 0.046 molmolꢀ1) was achieved under ambient
conditions, compared with CO solubility in a commonly used
IL [Bmim][Tf2N] (2 ꢀ 10ꢀ3 molmolꢀ1). The results of quantum
mechanical calculations and spectroscopic investigation con-
firmed that the chemical interaction between the C-site in the
carbanion and CO resulted in the superior CO absorption
capacities. Furthermore, the subsequent conversion of captured
CO into valuable chemicals with good reactivity was also
realized through the alkoxycarbonylation reaction under mild
conditions. Highly efficient CO absorption by carbanion-
functionalized ILs provides a new way of separating and
converting CO.
industrial gas feedstock for the C1 chemistry. Through the
carbonylation process, CO can be transformed into various
bulk chemicals, such as acetic acid, aldehydes, and esters.[2]
Therefore, research into the removal, purification, and
utilization of CO is very important in fields such as environ-
mental protection, chemistry, and industry.
Ionic liquids (ILs) are a class of state-of-the-art solvents
owing to their unique properties, such as virtually unlimited
tunability, negligible vapor pressure, excellent solubility, and
high thermal stability.[3–5] Thus, ILs have proved to be efficient
absorbents and reaction media for many gases, such as CO2,[6]
SO2,[7] H2S,[8] NO,[9] and N2O.[10] However, it is difficult for ILs
to capture CO, as a simple diatomic molecule, because it has
the highest bond dissociation energy among all the diatomic
molecules.[11] There are a limited number of studies concern-
ing the capture of CO by ILs.[12] For example, Laurenczyꢀs
group reported the first example of CO capture by an IL
([Bmim][Tf2N]) in 2004, in which a solubility of 1.25 ꢁ
10ꢀ3 mol CO per mol of IL was achieved at ambient
pressure.[12a] Thereafter, Peters et al. further investigated the
absorption of CO by [Bmim][Tf2N] at temperatures of up to
460 K and pressures of up to 10 MPa.[12e] These findings show
that the CO absorption capacities of ILs are very low; hence,
it is highly desirable to develop IL systems that are able to
efficiently capture CO at higher capacities.
C
arbon monoxide, which is mainly emitted from the exhaust
of internal combustion engines, is a colorless, odorless, but
very toxic gas for humans because of its high affinity for
hemoglobin. An efficient CO elimination treatment is
through the catalytic oxidation of CO into CO2 using noble
metals as catalysts.[1] However, this process results in the
increased emission of CO2, a major greenhouse gas, and an
additional process is required to treat the tail gas to reduce
the emission of CO2. On the other hand, CO is an important
CO can behave as a p-acid[13] and readily coordinate with
transition metals through CO-to-metal s-donation.[14] Taking
advantage of this interaction, a CuCl/[hmim][Cl] mixture was
found to be an efficient absorbent system that exhibits
considerable CO capture capacity.[15] However, this system is
analogous to the conventional solution of ammoniacal
cuprous chloride, which exhibits many drawbacks, such as
water sensitivity and the instability of Cu+ ions owing to
oxidation and disproportionation. Furthermore, CO is also
susceptible to attack by a nucleophilic species through
polarization of the CO triple bond.[16] A nucleophile possess-
ing strong nucleophilicity can react with CO efficiently. In
light of the two distinctive types of interactions for CO, can we
introduce these interactions into systems of CO capture by
ILs, and design novel and stable functionalized ILs for
efficient and reversible absorption of CO?
Herein, we present a promising system with significantly
enhanced CO capture by carbanion-functionalized ILs
through C-site interaction. The essence of our strategy is to
make use of the supernucleophilicity of carbanions to react
with CO reversibly and thereby to enhance the interaction
between ILs and CO. Thus, a high capacity for CO absorption
(up to 0.046 mol CO per mol IL) could be achieved under
ambient conditions. The interaction of carbanion-functional-
[*] Prof. Dr. D. J. Tao, F. F. Chen
College of Chemistry and Chemical Engineering, Jiangxi Inorganic
Membrane Materials Engineering Research Centre
Jiangxi Normal University, Nanchang 330022 (P.R. China)
E-mail: djtao@jxnu.edu.cn
Dr. K. Huang
School of Resources Environmental and Chemical Engineering
Nanchang University, Nanchang 330031 (P.R. China)
Dr. Z. Q. Tian, Prof. Dr. D. Jiang
Department of Chemistry, University of California
Riverside, CA 92521 (USA)
E-mail: djiang@ucr.edu
Dr. K. Huang, Prof. Dr. S. Dai
Department of Chemistry, University of Tennessee
Knoxville, TN 37996 (USA)
Dr. S. M. Mahurin, Prof. Dr. S. Dai
Chemical Sciences Division, Oak Ridge National Laboratory
Oak Ridge, TN 37831 (USA)
E-mail: dais@ornl.gov
Supporting information and the ORCID identification number(s) for
the author(s) of this article can be found under:
https://doi.org/10.1002/anie.201701919.
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Table 1: Absorption capacity of CO in carbanion-functionalized ILs
ized ILs with CO was further identified by quantum
mechanical calculations and by nuclear magnetic resonance
(NMR) and infrared (IR) spectroscopy. Furthermore, we
demonstrated that the captured CO could be converted into
valuable chemicals through the alkoxycarbonylation reaction
under mild conditions.
The carbanion-functionalized ILs (Figure 1) were pre-
pared by neutralization of various b-diketone compounds
with an ethanol solution of tributyl(octyl)phosphonium
hydroxide, which was obtained by the anion-exchange
method.[6h,17] The structures of these ILs were confirmed by
NMR and IR spectroscopy, mass spectrometry, and elemental
analysis. The physicochemical properties were characterized
by densimeter, viscometer, thermogravimetric analysis, and
differential scanning calorimetry. The characterization results
are presented in the Supporting Information, Table S1.
compared with other ILs.[a]
Absorbent
T
[8C]
p
[bar]
Solubility
Ref.
[molmolꢀ1
]
[P4448][Pen]
[P4448][Mho]
[P4448][Ido]
25
25
25
25
25
22
22
22
22
22
22
22
20
30
30
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
0.046
0.021
0.011
0.020
–
–
–
–
[P4448][Dib]
[P4442][Pen]
0.030
-
toluene[a]
7.8ꢀ10ꢀ14
4.4ꢀ10ꢀ4
1.3ꢀ10ꢀ3
2.1ꢀ10ꢀ3
3.0ꢀ10ꢀ3
5.2ꢀ10ꢀ3
2.9ꢀ10ꢀ3
2.6ꢀ10ꢀ3
1.5ꢀ10ꢀ3
0.020
[12a]
[12a]
[12a]
[12a]
[12a]
[12a]
[12a]
[12c]
[12d]
[15a]
methanol[a]
1-decene[a]
1-hexene[a]
[Bmim][PF6][a]
[Bmim][CF3COO][a]
[Bmim][BF4][a]
[Bmim][CH3SO4][a]
[Bmim][Tf2N][a]
CuCl/[hmim][Cl]
[a] The solubilities at 1.0 bar were estimated according to Henry’s law:
KH =PCO/xCO
.
absorption of CO in carbanion ILs may be kinetically
controlled owing to a high activation energy. In other words,
increasing the temperature could reduce the kinetic barrier
and promote this reaction efficiently. Furthermore, the
solubilities of a binary mixture 50% CO + 50% N2 and
pure N2 in [P4448][Pen] were measured at 258C and 1 bar,
respectively. It is remarkable that [P4448][Pen] showed very
low capacity for capturing pure N2 (Supporting Information,
Figure S2). In contrast, [P4448][Pen] retained a relatively high
CO absorption capacity of 0.034 molmolꢀ1 for the absorption
of the mixture of CO and N2 (Supporting Information,
Table S2). Thus, it is demonstrated that carbanion-function-
alized ILs can capture CO efficiently, even at a low CO
concentration, showing great potential for selective separa-
tion of CO from N2.
Why did [P4448][Pen] show such high CO absorption
capacity? To illustrate the underlying mechanism, we first
estimated CO solubility in various ILs based on pure physical
interaction. With the COSMOtherm program,[18] simulated
CO solubilities of [P4448][Pen] and [Bmim][Tf2N] were 2.06 ꢁ
10ꢀ3 and 1.64 ꢁ 10ꢀ3 molmolꢀ1, respectively. The latter value is
in good agreement with experiment, while the former under-
estimated significantly. Thus there must be stronger inter-
action between [Pen] anion and CO rather than the normal
physical interaction. Subsequently, we employed density
functional calculations at the M06-2x/6-311G ++ (d,p)
level[19] to investigate the interaction of [Pen] and [Tf2N]
with CO. The calculated binding DH between [Tf2N] and CO
is ꢀ11.8 kJmolꢀ1 (Figure 2b), implying physisorption, which
is supported by the large CO–anion separation of 3.573 ꢂ.
Similarly, if [Pen] attracts CO by non-bonded interaction only,
DH is ꢀ13.6 kJmolꢀ1, which is also close to that of [Tf2N] and
in consistent with the result from COSMOtherm prediction
but far away from the experimental data. Thus, considering
the supernucleophilicity of carbanions, we propose the
formation of a product consisting of an aldehyde group
between [Pen]-CO, as shown in Figure 2a, where CO is
Figure 1. Structures of the anions and the cation in carbanion-func-
tionalized ionic liquids.
First, we determined the solubilities of CO in these
carbanion-functionalized ILs under ambient conditions
(Table 1). To our surprise, the ILs showed a very high
capacity for capturing CO at room temperature and atmos-
pheric pressure. For example, absorption of 0.046 mol CO per
mol IL was achieved in [P4448][Pen] at 258C and 1 bar. The
other four carbanion-functionalized ILs also exhibited excel-
lent CO capture capacities of up to 0.030 mol CO per mol IL.
However, the solubility of CO in [Bmim][Tf2N] was as low as
2 ꢁ 10ꢀ3 molmolꢀ1 (Supporting Information, Figure S1). Thus,
compared to the data from previous studies, carbanion-
functionalized ILs were found to be superior to most other
ILs and traditional organic solvents in terms of CO uptake
(Table 1). Moreover, the effects of pressure and the temper-
ature on CO absorption were investigated (Supporting
Information, Table S2). It is seen that the CO absorption
capacity of [P4448][Pen] increased to 0.077 mol CO per mol IL
when the partial pressure was increased to 3 bar, indicating
that high pressure is favorable to CO capture. And it is also
notable that the CO absorption capacity of [P4448][Pen]
improved slightly, from 0.046 to 0.052 mol per mol IL, when
the temperature increased from 258C to 508C. A similar
behavior has also been observed in the absorption of CO in
other ILs as reported by Maurer.[12c] It is considered that the
2
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istic peaks were observed at 1508 cmꢀ1 and 2730 cmꢀ1, which
ꢀ
can be assigned to the stretching vibration of C C and the
ꢀ
ꢀ
stretching vibration of C H in the [Pen] CO interaction,
respectively. However, the stretching vibration peak of the
carbonyl group in captured CO was not clearly observed in
Figure 3. Therefore, we then calculated the FTIR difference
spectra of [P4448][Pen] and [P4448][Pen] + CO in the range of
1400 to 1800 cmꢀ1 [21]
As shown in Figure 4, the peak
.
Figure 2. Optimized structures of a) [Pen]-CO and b) [Tf2N]-CO.
Anion–CO distances (in ꢁ) and DH of interaction are also shown.
C gray, O red, N blue, S yellow, H white, F blue.
ꢀ
inserted into the C H bond at the carbanion site. The reaction
energy between [Pen] and CO was calculated to be rather
favorable, at ꢀ77.6 kJmolꢀ1, and the other three carbanion-
functionalized ILs could also react with CO very favorably
(Supporting Information, Figure S3). This carbonanion–CO
chemistry is very similar to the industrial synthesis of methyl
formate, in which CH3OH and CO are combined in the
presence of a strong base (for example, potassium meth-
oxide).[20] Furthermore, we analyzed the atomic charges of the
carbon atoms in the carbanion and the complex of the
carbanion with CO by natural bond orbital (NBO) analysis
(Supporting Information, Figure S4). After complexing with
CO, the partial atomic charge on the C-site in [Pen] becomes
less negative by 0.101 j e j , which is close to the decreased
positive charge on the carbon atom in CO (0.095 j e j). Hence,
such strong chemical interactions made the capture of CO by
carbanion-functionalized ILs more efficient than its capture
by conventional ILs such as [Bmim][Tf2N].
Figure 4. Comparison of FTIR difference spectra of [P4448][Pen] and
[P4448][Pen]+CO in the range of 1400 to 1800 cmꢀ1
.
appearing at 1592 cmꢀ1 can be assigned to the stretching
vibration of the carbonyl group in captured CO. Compared
with free CO (2143 cmꢀ1),[22] the vibrational frequency of
captured CO was obviously red-shifted to 1592 cmꢀ1, dem-
onstrating the strong chemical interaction of [Pen] with CO.
Thus, on the basis of the FTIR spectra results, it is validated
ꢀ
that CO was inserted into the C H bond at the carbanion site
and formed a product consisting of aldehyde group. Further-
more, it is seen in Figure 5 that a new signal at d = 205.1 ppm
appeared in the 13C NMR after 0.046 mol CO uptake per mol
IL, which is clearly attributable to the captured CO, further
verifying the presence of aldehyde group in the [Pen]-CO
chemical interaction. Meanwhile, the resonance of the
carbonyl carbon atom in [Pen] showed a downfield shift
The C-site interaction between [Pen] and CO was verified
by Fourier transform infrared (FTIR) and 13C NMR spec-
troscopy. In the FTIR spectra (Figure 3), two new character-
Figure 3. FTIR spectra of [P4448][Pen] before and after the capture of
Figure 5. 13C NMR spectra of [P4448][Pen] before and after the capture
CO.
of CO.
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from d = 172.6 ppm to d = 173.5 ppm because of the change in
the partial atomic charge on the C-site. Therefore, on the basis
of observed results, a plausible mechanism of CO absorption
by [Pen] can be proposed (Scheme 1), which exhibits a C-site
chemical interaction between [Pen] and CO.
ion-based ILs has great potential for CO separation and
conversion.
Acknowledgements
D.J.T. and F.F.C. were supported by the National Natural
Science Foundation of China (21566011, 31570560), the
Natural Science Foundation of Jiangxi Province
(20151BAB213016), and the Natural Science Foundation of
Jiangxi Province for Distinguished Young Scholars
(20162BCB23026). K.H., Z.Q.T., D.J., S.M.M., and S.D.
were supported by the U.S. Department of Energy, Office
of Science, Basic Energy Sciences, Chemical Sciences, Geo-
sciences, and Biosciences Division.
Scheme 1. The proposed mechanism of CO absorption by [P4448][Pen]
through C-site interaction.
Multiple cycles of CO absorption/desorption in [P4448]-
[Pen] at 258C were then investigated (Supporting Informa-
tion, Figure S5). It was illustrated that the CO absorption
capacity could remain steady during five cycles, showing that
this CO capture process by [P4448][Pen] is highly reversible.
Also, there was no obvious change in the characteristic bands
of IR and NMR spectra between the fresh and reused
[P4448][Pen] ILs (Supporting Information, Figures S6, S7),
demonstrating that [P4448][Pen] is stable enough to be
recycled. Furthermore, it is believed that captured CO
could be more reactive than free CO and undergo subsequent
conversion to produce valuable chemicals through the
carbonylation reaction.[23] Thus, the strategy for CO capture
and utilization was examined for the catalytic synthesis of
benzoate using iodobenzene, alcohol, and CO as raw materi-
als (Scheme 2). We found that the captured CO in [P4442][Pen]
could react with iodobenzene and n-butanol effortlessly to
produce butyl benzoate with a yield of 88% under room
temperature and atmospheric pressure. Alkoxycarbonylation
reactions of captured CO with other alcohols were also
conducted to obtain various benzoate products with good
yields (Supporting Information, Table S3).
Conflict of interest
The authors declare no conflict of interest.
Keywords: carbanions · CO capture · C-sites · ionic liquids ·
supernucleophilicity
[1] a) T. Engel, G. Ertl, J. Chem. Phys. 1978, 69, 1267; b) M. Haruta,
T. Kobayashi, H. Sano, N. Yamada, Chem. Lett. 1987, 405 – 408.
[2] a) A. Brennfꢃhrer, H. Neumann, M. Beller, Angew. Chem. Int.
Ed. 2009, 48, 4114 – 4133; Angew. Chem. 2009, 121, 4176 – 4196;
b) Q. Liu, H. Zhang, A. W. Lei, Angew. Chem. Int. Ed. 2011, 50,
10788 – 10799; Angew. Chem. 2011, 123, 10978 – 10989; c) P. Hu,
H. R. Yazdi, G. Stephanopoulos, AIChE J. 2013, 59, 3176 – 3183;
d) H. Konishi, K. Manabe, Synlett 2014, 1971 – 1986.
[3] a) L. A. Blanchard, D. Hancu, E. J. Beckman, J. F. Brennecke,
Nature 1999, 399, 28 – 29; b) R. D. Rogers, K. R. Seddon, Science
2003, 302, 792 – 793.
[4] a) T. Welton, Chem. Rev. 1999, 99, 2071 – 2083; b) M. Petkovic,
K. R. Seddon, L. P. N. Rebelo, C. S. Pereira, Chem. Soc. Rev.
2011, 40, 1383 – 1403; c) P. J. Hallett, T. Welton, Chem. Rev. 2011,
111, 3508 – 3576.
[5] a) C. Maton, N. D. Vos, C. V. Stevens, Chem. Soc. Rev. 2013, 42,
5963 – 5977; b) Z. G. Lei, C. N. Dai, B. H. Chen, Chem. Rev.
2013, 113, 1289 – 1326.
Scheme 2. The subsequent reaction of n-butanol with captured CO in
[P4442][Pen] to synthesize n-butyl benzoate.
[6] a) E. D. Bates, R. D. Mayton, I. Ntai, J. H. Davis, J. Am. Chem.
Soc. 2002, 124, 926 – 927; b) C. Cadena, J. L. Anthony, J. K. Shah,
T. I. Morrow, J. F. Brennecke, E. J. Maginn, J. Am. Chem. Soc.
2004, 126, 5300 – 5308; c) B. E. Gurkan, J. C. de la Fuente, E. M.
Mindrup, L. E. Ficke, B. F. Goodrich, E. A. Price, W. F.
Schneider, J. F. Brennecke, J. Am. Chem. Soc. 2010, 132, 2116 –
2117; d) C. M. Wang, H. M. Luo, D. E. Jiang, H. R. Li, S. Dai,
Angew. Chem. Int. Ed. 2010, 49, 5978 – 5981; Angew. Chem. 2010,
122, 6114 – 6117; e) G. Gurau, H. Rodrꢄguez, S. P. Kelley, P.
Janiczek, R. S. Kalb, R. D. Rogers, Angew. Chem. Int. Ed. 2011,
50, 12024 – 12026; Angew. Chem. 2011, 123, 12230 – 12232;
f) X. Y. Luo, Y. Guo, F. Ding, H. Q. Zhao, G. K. Cui, H. R. Li,
C. M. Wang, Angew. Chem. Int. Ed. 2014, 53, 7053 – 7057;
Angew. Chem. 2014, 126, 7173 – 7177; g) G. K. Cui, J. J. Wang,
S. J. Zhang, Chem. Soc. Rev. 2016, 45, 4307 – 4339; h) F. F. Chen,
K. Huang, Y. Zhou, Z. Q. Tian, X. Zhu, D. J. Tao, D. E. Jiang, S.
Dai, Angew. Chem. Int. Ed. 2016, 55, 7166 – 7170; Angew. Chem.
2016, 128, 7282 – 7286; i) A. H. Liu, R. Ma, C. Song, Z. Z. Yang,
A. Yu, Y. Cai, L. N. He, Y. N. Zhao, B. Yu, Q. W. Song, Angew.
In summary, we developed a novel strategy for the capture
of CO by carbanion-functionalized ILs through C-site inter-
action. It was illustrated that the carbanion in the ILs could
interact with CO very efficiently and high CO absorption
capacities (up to 0.046 mol CO per mol IL under ambient
conditions) were thus achieved. Quantum mechanical calcu-
lations and spectroscopic investigations show that the C-site
chemical interaction takes place between the carbanion and
CO, and the CO absorption enthalpy is as high as
ꢀ77.6 kJmolꢀ1. Furthermore, the captured CO in carbanion-
functionalized ILs could be utilized for the synthesis of
benzoates at high yields under mild conditions. We believe
that this highly efficient and reversible process using carban-
4
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Chem. Int. Ed. 2012, 51, 11306 – 11310; Angew. Chem. 2012, 124,
Neaton, S. Bordiga, C. M. Brown, J. R. Long, J. Am. Chem. Soc.
11468 – 11472; j) Y. F. Zhao, B. Yu, Z. Z. Yang, H. Y. Zhang,
L. D. Hao, X. Gao, Z. M. Liu, Angew. Chem. Int. Ed. 2014, 53,
5922 – 5925; Angew. Chem. 2014, 126, 6032 – 6035; k) J. Y. Hu, J.
Ma, Q. G. Zhu, Z. F. Zhang, C. Y. Wu, B. X. Han, Angew. Chem.
Int. Ed. 2015, 54, 5399 – 5403; Angew. Chem. 2015, 127, 5489 –
5493; l) K. H. Chen, G. L. Shi, W. D. Zhang, H. R. Li, C. M.
Wang, J. Am. Chem. Soc. 2016, 138, 14198 – 14201.
2014, 136, 10752 – 10761.
[15] a) O. C. David, G. Zarca, D. Gorri, A. Urtiaga, I. Ortiz, Sep.
Purif. Technol. 2012, 97, 65 – 72; b) G. Zarca, I. Ortiz, A. Urtiaga,
Chem. Eng. J. 2014, 252, 298 – 304.
[16] D. F. Shriver, ACS Symp. Ser. 1981, 152, 1 – 18.
[17] C. M. Wang, X. Y. Luo, H. M. Luo, D. Jiang, H. R. Li, S. Dai,
Angew. Chem. Int. Ed. 2011, 50, 4918 – 4922; Angew. Chem.
2011, 123, 5020 – 5024.
[18] a) F. Eckert, A. Klamt, COSMOtherm, VersionC3.0
Release16.01; COSMOlogic GmbH & Co. KG, Leverkusen,
Germany, 2015; b) F. Eckert, A. Klamt, AIChE J. 2002, 48, 369 –
385.
[19] M. J. Frisch, G. W. Trucks, H. B. Schlegel, G. E. Scuseria, M. A.
Robb, J. R. Cheeseman, G. Scalmani, V. Barone, B. Mennucci,
G. A. Petersson, H. Nakatsuji, M. Caricato, X. Li, H. P.
Hratchian, A. F. Izmaylov, J. Bloino, G. Zheng, J. L. Sonnenberg,
M. Hada, M. Ehara, K. Toyota, R. Fukuda, J. Hasegawa, M.
Ishida, T. Nakajima, Y. Honda, O. Kitao, H. Nakai, T. Vreven,
J. A. E. Montgomery, Jr., J. Peralta, F. Ogliaro, M. Bearpark, J. J.
Heyd, E. Brothers, K. N. Kudin, V. N. Staroverov, R. Kobayashi,
J. Normand, K. Raghavachari, A. Rendell, J. C. Burant, S. S.
Iyengar, J. Tomasi, M. Cossi, N. Rega, J. M. Millam, M. Klene,
J. E. Knox, J. B. Cross, V. Bakken, C. Adamo, J. Jaramillo, R.
Gomperts, R. E. Stratmann, O. Yazyev, A. J. Austin, R. Cammi,
C. Pomelli, J. W. Ochterski, R. L. Martin, K. Morokuma, V. G.
Zakrzewski, G. A. Voth, P. Salvador, J. J. Dannenberg, S.
Dapprich, A. D. Daniels, O. Farkas, J. B. Foresman, J. V. Ortiz,
J. Cioslowski, D. J. Fox, Gaussian09, RevisionD.01; Gaussian,
Inc.: Wallingford, CT, 2009.
[7] a) W. Z. Wu, B. X. Han, H. X. Gao, Z. M. Liu, T. Jiang, J. Huang,
Angew. Chem. Int. Ed. 2004, 43, 2415; Angew. Chem. 2004, 116,
2469; b) Y. Y. Jiang, Z. Zhou, Z. Jiao, L. Li, Z. B. Zhang, Y. T.
Wu, J. Phys. Chem. B 2007, 111, 5058 – 5061; c) C. M. Wang,
G. K. Cui, X. Y. Luo, Y. J. Xu, H. R. Li, S. Dai, J. Am. Chem. Soc.
2011, 133, 11916 – 11919; d) G. K. Cui, J. J. Zheng, X. Y. Luo,
W. J. Lin, F. Ding, H. R. Li, C. M. Wang, Angew. Chem. Int. Ed.
2013, 52, 10620 – 10624; Angew. Chem. 2013, 125, 10814 – 10818;
e) K. Huang, Y. L. Chen, X. M. Zhang, S. Xia, Y. T. Wu, X. B.
Hu, Chem. Eng. J. 2014, 237, 478 – 486.
[8] a) F. Y. Jou, A. E. Mather, Int. J. Thermophys. 2007, 28, 490 –
495; b) A. L. Revelli, F. Mutelet, J. N. Jaubert, J. Phys. Chem. B
2010, 114, 8199 – 8206; c) K. Huang, D. N. Cai, Y. L. Chen, Y. T.
Wu, X. B. Hu, Z. B. Zhang, AIChE J. 2013, 59, 2227 – 2235; d) K.
Huang, X. M. Zhang, Y. Xu, Y. T. Wu, X. B. Hu, AIChE J. 2014,
60, 4232 – 4240; e) K. Huang, X. M. Zhang, X. B. Hu, Y. T. Wu,
AIChE J. 2016, 62, 4480 – 4490.
[9] a) K. H. Chen, G. H. Shi, X. Y. Zhou, H. R. Li, C. M. Wang,
Angew. Chem. Int. Ed. 2016, 55, 14364 – 14368; Angew. Chem.
2016, 128, 14576 – 14580; b) E. Duan, B. Guo, D. Zhang, L. Shi,
H. Sun, Y. Wang, J. Air Waste Manage. Assoc. 2011, 61, 1393 –
1397; c) B. Jiang, W. R. Lin, L. H. Zhang, Y. L. Sun, H. W. Yang,
L. Hao, X. W. Tantai, Energy Fuels 2016, 30, 735 – 739.
[10] M. B. Shiflett, A. M. S. Niehaus, A. Yokozeki, J. Phys. Chem. B
2011, 115, 3478 – 3487.
[20] O. Jogunola, T. Salmi, M. Kangas, J.-P. Mikkola, Chem. Eng. J.
2012, 203, 469 – 479.
[21] Intensity normalization of FTIR spectra of [P4448][Pen] and
[P4448][Pen] + CO were conducted in the range of 1400 to
[11] J. A. Coxon, P. G. Hajigeorgiou, J. Chem. Phys. 2004, 121, 2992 –
3008.
1800 cmꢀ1
. The FTIR difference spectra was obtained by
[12] a) C. A. Ohlin, P. J. Dyson, G. Laurenczy, Chem. Commun. 2004,
1070 – 1071; b) J. L. Anthony, E. J. Maginn, J. F. Brennecke, J.
Phys. Chem. B 2002, 106, 7315 – 7320; c) J. Kumełan, ꢅ. P. S.
Kamps, D. T. G. Maurer, Fluid Phase Equilib. 2007, 260, 3 – 8;
d) Q. Gan, Y. R. Zou, D. Rooney, P. Nancarrow, J. L. Thompson,
L. Z. Liang, M. Lewis, Adv. Colloid Interface Sci. 2011, 164, 45 –
55; e) S. Raeissi, L. J. Florusse, C. J. Peters, AIChE J. 2013, 59,
3886 – 3891.
subtracting spectra of [P4448][Pen] + CO from that of [P4448][Pen]
after their normalization.
[22] a) S. Chavan, J. G. Vitillo, E. Groppo, F. Bonino, C. Lamberti,
P. D. C. Dietzel, S. Bordiga, J. Phys. Chem. C 2009, 113, 3292 –
3299; b) L. Valenzano, B. Civalleri, S. Chavan, G. T. Palomino,
C. O. Areꢇn, S. Bordiga, J. Phys. Chem. C 2010, 114, 11185 –
11191; c) S. Bordiga, F. Bonino, K. P. Lillerud, C. Lamberti,
Chem. Soc. Rev. 2010, 39, 4885 – 4927.
[13] D. A. Reed, D. J. Xiao, M. I. Gonzalez, L. E. Darago, Z. R.
Herm, F. Grandjean, J. R. Long, J. Am. Chem. Soc. 2016, 138,
5594 – 5602.
[23] a) J. H. Liu, J. Chen, C. G. Xia, J. Catal. 2008, 253, 50 – 56; b) J.
Salvadori, E. Balducci, S. Zaza, E. Petricci, M. Taddei, J. Org.
Chem. 2010, 75, 1841 – 1847.
[14] a) H. Sato, W. Kosaka, R. Matsuda, A. Hori, Y. Hijikata, R. V.
Belosludov, S. Sakaki, M. Takata, S. Kitagawa, Science 2014, 343,
167 – 170; b) E. D. Bloch, M. R. Hudson, J. A. Mason, S. Chavan,
V. Crocellꢆ, J. D. Howe, K. Lee, A. L. Dzubak, W. L. Queen,
J. M. Zadrozny, S. J. Geier, L. C. Lin, L. Gagliardi, B. Smit, J. B.
Manuscript received: February 23, 2017
Final Article published: && &&, &&&&
Angew. Chem. Int. Ed. 2017, 56, 1 – 6
ꢀ 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.angewandte.org
5
These are not the final page numbers!

Angewandte
Communications
Chemie
Communications
CO Capture
D. J. Tao,* F. F. Chen, Z. Q. Tian,
K. Huang, S. M. Mahurin, D. Jiang,*
S. Dai*
&&&& — &&&&
Highly Efficient Carbon Monoxide
Capture by Carbanion-Functionalized
Ionic Liquids through C-site Interactions
Carbanions licensed to IL: A highly effi-
cient and reversible capture of CO in
carbanion-functionalized ionic liquids
was achieved (up to 0.046 molmolꢀ1
under ambient conditions). The C-site
chemical interaction between the carb-
anion and CO is responsible for the
superior CO absorption capacities.
6
www.angewandte.org
ꢀ 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Angew. Chem. Int. Ed. 2017, 56, 1 – 6
These are not the final page numbers!