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Volume 69 
Part 8 
Pages o1218-o1219  
August 2013  

Received 7 June 2013
Accepted 1 July 2013
Online 6 July 2013

Key indicators
Single-crystal X-ray study
T = 296 K
Mean [sigma](C-C) = 0.002 Å
R = 0.028
wR = 0.081
Data-to-parameter ratio = 10.2
Details
Open access

Bis(1,3-dimethyl-1H-imidazolium) hexafluorosilicate: the second monoclinic polymorph

aCollege of Chemistry, Leshan Normal University, Binhe Rd 778, Leshan 614000, Sichuan Province, People's Republic of China
Correspondence e-mail: maxborzov@mail.ru

The title compound, 2C5H9N2+·SiF62-, (I), crystallized as a new polymorph, different from the previously reported one (Ia) [Light et al. (2007[Light, M. E., Bates, G. W. & Gale, P. A. (2007). Private communication (refcode NIQFAV). CCDC, Cambridge, England.]) private communication (refcode: NIQFAV). CCDC, Cambridge, England]. The symmetry [space groups P21/n for (I) and C2/c for(Ia)] and crystal packing patterns are markedly different for this pair of polymorphs. In (I), all imidazolium cations in the lattice are nearly parallel to each other, whereas a herringbone arrangement can be found in (Ia). In (I), each SiF62- dianion forms four short C-H...F contacts with adjacent C5H9N2+ cations, resulting in the formation of layers parallel to the ac plane. In (Ia), the C-H...F contacts are generally longer and result in the formation of layers along the bc plane.

Related literature

For the structure of the previously reported polymorph of (I)[link] and its solvatomorph 6C5H9N2+·3SiF62-·CH3OH, see: Light et al. (2007[Light, M. E., Bates, G. W. & Gale, P. A. (2007). Private communication (refcode NIQFAV). CCDC, Cambridge, England.]) and Tian et al. (2013[Tian, C., Nie, W. & Borzov, M. V. (2013). Acta Cryst. E69, o1216-o1217.]), respectively. For an overview of polymorphism, see: Bernstein (2002[Bernstein, J. (2002). Polymorphism in Molecular Crystals, Oxford: Clarendon Press.]); Linden (2011[Linden, A. (2011). Acta Cryst. C67, e15.]). For the practical importance of sterically non-hindered 1,3-dialkyl-1H-imidazolium salts with perfluoro anions of the main-group elements in the preparation of Arduengo carbene adducts, see: Tian et al. (2012[Tian, C., Nie, W., Borzov, M. V. & Su, P. (2012). Organometallics, 31, 1751-1760.]). For graph-set notation, see: Etter et al. (1990[Etter, M. C., MacDonald, J. C. & Bernstein, J. (1990). Acta Cryst. B46, 256-262.]); Bernstein et al. (1995[Bernstein, J., Davis, R. E., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem. Int. Ed. Engl. 34, 1555-1573.]); Grell et al. (1999[Grell, J., Bernstein, J. & Tinhofer, G. (1999). Graph Set Analysis of Some Hydrogen Bond Patterns. Some Mathematical Concepts, edited by H. Wähling. München: Fakultät für Mathematik und Informatik, Technische Universität München.]).

[Scheme 1]

Experimental

Crystal data
  • 2C5H9N2+·SiF62-

  • Mr = 336.38

  • Monoclinic, P 21 /n

  • a = 8.2240 (8) Å

  • b = 9.7901 (9) Å

  • c = 8.7753 (9) Å

  • [beta] = 90.106 (1)°

  • V = 706.53 (12) Å3

  • Z = 2

  • Mo K[alpha] radiation

  • [mu] = 0.23 mm-1

  • T = 296 K

  • 0.40 × 0.39 × 0.05 mm

Data collection
  • Bruker SMART APEXII diffractometer

  • Absorption correction: multi-scan (SADABS; Sheldrick, 1996[Sheldrick, G. M. (1996). SADABS. University of Göttingen, Germany.]) Tmin = 0.913, Tmax = 0.988

  • 3670 measured reflections

  • 1373 independent reflections

  • 1228 reflections with I > 2[sigma](I)

  • Rint = 0.020

Refinement
  • R[F2 > 2[sigma](F2)] = 0.028

  • wR(F2) = 0.081

  • S = 1.09

  • 1373 reflections

  • 134 parameters

  • All H-atom parameters refined

  • [Delta][rho]max = 0.18 e Å-3

  • [Delta][rho]min = -0.22 e Å-3

Table 1
Hydrogen-bond geometry (Å, °)

D-H...A D-H H...A D...A D-H...A
C1-H1...F3 0.884 (18) 2.164 (19) 2.9622 (17) 149.8 (14)
C2i-H2i...F2 0.934 (19) 2.26 (2) 3.1935 (18) 174.0 (5)
Symmetry code: (i) [-x+{\script{1\over 2}}, y+{\script{1\over 2}}, -z+{\script{3\over 2}}].

Data collection: APEX2 (Bruker, 2007[Bruker (2007). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2007[Bruker (2007). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]) and OLEX2 (Dolomanov et al., 2009[Dolomanov, O. V., Bourhis, L. J., Gildea, R. J., Howard, J. A. K. & Puschmann, H. (2009). J. Appl. Cryst. 42, 339-341.]); software used to prepare material for publication: SHELXTL and OLEX2.


Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: LD2107 ).


Acknowledgements

Financial support from the National Natural Science Foundation of China (project Nos. 20702041 and 21072157) and the Shaanxi Province Administration of Foreign Experts Bureau Foundation (grant No. 20106100079) is gratefully acknowledged. The authors are thankful to Mr Su Pengfei (Xi'an Modern Chemistry Research Institute) for his help in carrying out the X-ray diffraction measurements.

References

Bernstein, J. (2002). Polymorphism in Molecular Crystals, Oxford: Clarendon Press.
Bernstein, J., Davis, R. E., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem. Int. Ed. Engl. 34, 1555-1573.  [CrossRef] [ChemPort] [Web of Science]
Bruker (2007). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.
Dolomanov, O. V., Bourhis, L. J., Gildea, R. J., Howard, J. A. K. & Puschmann, H. (2009). J. Appl. Cryst. 42, 339-341.  [Web of Science] [CrossRef] [ChemPort] [IUCr Journals]
Etter, M. C., MacDonald, J. C. & Bernstein, J. (1990). Acta Cryst. B46, 256-262.  [CrossRef] [Web of Science] [IUCr Journals]
Grell, J., Bernstein, J. & Tinhofer, G. (1999). Graph Set Analysis of Some Hydrogen Bond Patterns. Some Mathematical Concepts, edited by H. Wähling. München: Fakultät für Mathematik und Informatik, Technische Universität München.
Light, M. E., Bates, G. W. & Gale, P. A. (2007). Private communication (refcode NIQFAV). CCDC, Cambridge, England.
Linden, A. (2011). Acta Cryst. C67, e15.  [CrossRef] [IUCr Journals]
Sheldrick, G. M. (1996). SADABS. University of Göttingen, Germany.
Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.  [CrossRef] [ChemPort] [IUCr Journals]
Tian, C., Nie, W. & Borzov, M. V. (2013). Acta Cryst. E69, o1216-o1217.  [CrossRef] [IUCr Journals]
Tian, C., Nie, W., Borzov, M. V. & Su, P. (2012). Organometallics, 31, 1751-1760.  [CSD] [CrossRef] [ChemPort]


Acta Cryst (2013). E69, o1218-o1219   [ doi:10.1107/S1600536813018242 ]

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