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SHUANG MEN, YUJUAN JIN
Table 2. Binding energies of all elements for [C4C1Im-2-PF5] and [C4C1Im][PF6]
Binding energy, eV
Ionic liquids
C2 1s
Caliphatic 1s
C
hetero 1s
P 2p3/2
N 1s
F 1s
[C4C1Im-2-PF5]
[C4C1Im][PF6]
285.0
285.2
287.2
287.7
286.5
286.7
401.8
402.1
686.6
686.6
136.1
136.7
2. S. Caporali, U. Bardi, and A. Lavacchi, J. Electron
sequently, the measured change in electronic environ-
ment is found more noticeable on the phosphorus
atom, as demonstrated in Fig. 2d. It is found that the
binding energy of P 2p3/2 for [C4C1Im-2-PF5] shifted
0.6 eV to lower value, compared to that of
[C4C1Im][PF6].
Spectrosc. Rel. Phenom. 151, 4 (2006).
3. T. Cremer, C. Kolbeck, K. R. J. Lovelock, N. Paape,
R. Wolfel, P. S. Schulz, P. Wasserscheid, H. Weber,
J. Thar, B. Kirchner, F. Maier, and H.-P. Steinruck,
Chem.-Eur. J. 16, 9018 (2010).
4. I. J. Villar-Garcia, E. F. Smith, A. W. Taylor, F. Qiu,
K. R. J. Lovelock, R. G. Jones, and P. Licence, Phys.
Chem. Chem. Phys. 13, 2797 (2011).
CONCLUSIONS
5. S. Men, K. R. J. Lovelock, and P. Licence, Phys.
We have successfully investigated [C4C1Im-2-PF5]
and [C4C1Im][PF6] by XPS. The intramolecular
charge-transfer from negative headgroup to the positive
one is revealed in detail. In the case of [C4C1Im-2-PF5],
due to the intense charge-transfer effect, binding ener-
gies of N 1s and C2 1s are found lower; whilst binding
energy of P 2p3/2 is higher, when compared to those of
[C4C1Im][PF6]. Unexpectedly, the measured F 1s bind-
ing energy for [C4C1Im-2-PF5] and [C4C1Im][PF6] is
found consistent with each other. As there are five flu-
orine atoms present in the [C4C1Im-2-PF5], the
change of the electronic environment due to the
charge-transfer effect has been diluted.
Chem. Chem. Phys. 13, 15244 (2011).
6. I. J. Villar-Garcia, K. R. J. Lovelock, S. Men, and
P. Licence, Chem. Sci. 5, 2573 (2014).
7. S. Men and J. Jiang, Chem. Phys. Lett. 677, 60 (2017).
8. S. Das, S. Santra, P. Mondal, A. Majee, and A. Hajra,
Synthesis 48, 1269 (2016).
9. A. W. Taylor, K. R. J. Lovelock, R. G. Jones, and
P. Licence, Dalton Trans. 40, 1463 (2011).
10. S. Men, J. Jiang, and Y. Liu, J. Appl. Spectrosc. 84, 906
(2017).
11. C. Tian, W. Nie, M. V. Borzov, and P. Su, Organome-
tallics 31, 1751 (2012).
12. J. G. Huddleston, A. E. Visser, W. M. Reichert,
H. D. Willauer, G. A. Broker, and R. D. Rogers, Green
Chem. 3, 156 (2001).
ACKNOWLEDGMENTS
13. P. A. Z. Suarez, J. E. L. Dullius, S. Einloft,
R. F. DeSouza, and J. Dupont, Polyhedron 15, 1217
(1996).
14. A. W. Taylor, K. R. J. Lovelock, A. Deyko, P. Licence,
and R. G. Jones, Phys. Chem. Chem. Phys. 12, 1772
(2010).
15. C. D. Wagner, L. E. Davis, M. V. Zeller, J. A. Taylor,
R. H. Raymond, and L. H. Gale, Surf. Interface Anal.
3, 211 (1981).
16. D. Briggs and J. T. Grant, Surface Analysis by Auger and
X-ray Photoelectron Spectroscopy (IM Publ., Manches-
ter, 2003).
We thank National Science Foundation
(51503007), the General project of Science and Tech-
nology Research Project of Liaoning Provincial
Department of Education (L2015461), Liaoning Pro-
vincial Foundation of Science and Technology
(20170540780) and China Postdoctoral Science
Foundation funded project (2015M571344) for finan-
cial support. SM acknowledges Beijing Key Labora-
tory of Quality Evaluation Technology for Hygiene
and Safety of Plastics (Beijing Technology and Busi-
ness University, Beijing 100048, China) for the award
of an Open Fund (SS201706).
17. S. Men, J. Jiang, and P. Licence, Chem. Phys. Lett.
674, 86 (2017).
18. S. Men, J. Rong, T. Zhang, X. Wang, L. Feng, C. Liu,
and Y. Jin, Russ. J. Phys. Chem. A 92 (10) (2018, in
press).
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RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY A
Vol. 92
No. 11
2018