research communications\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890

Crystal structure of the tetra­gonal polymorph of bis­­(1-ethyl-3-methyl­imidazolium) tetra­bromido­cadmate

CROSSMARK_Color_square_no_text.svg

aInstitut für Mineralogie und Kristallographie, Universität Wien, Althanstrasse 14, A-1090 Vienna, Austria, and bLaboratory of Crystallography, Faculty of Mining and Geology, Đušina 7, 11000 Belgrade, Serbia
*Correspondence e-mail: tamara.djordjevic@univie.ac.at

Edited by M. Weil, Vienna University of Technology, Austria (Received 14 April 2016; accepted 17 June 2016; online 24 June 2016)

Both unique Cd atoms in the tetra­gonal polymorph of bis­(1-ethyl-3-methyl­imidazolium) tetra­bromido­cadmate, (C6H11N2)2[CdBr4], occupy special positions (site symmetry -4). The crystal structure consists of isolated tetra­hedral [CdBr4]2− anions which are surrounded by 1-ethyl-3-methyl­imidazolium cations. The methyl and ethyl side chains of the cations show positional disorder in a 0.590 (11):0.410 (11) ratio. In the crystal, (C6H11N2)+ cations display three weak C—H⋯Br hydrogen-bond inter­actions through the imidazolium ring H atoms with the Br ligands of the surrounding complex anions. The alkyl groups of the side chains are not involved in hydrogen bonding.

1. Chemical context

Laboratories around the world have used ionic liquids to prepare many different types of solids, ranging from nanoparticles of different types, to semiconductors, and inorganic and organic solids (Morris, 2009[Morris, R. E. (2009). Chem. Commun. pp. 2990-2998.]). In an attempted synthesis of mineral-related arsenates, the ionic liquid 1-ethyl-3-methyl­imidazolium bromide (eminBr), C6H11BrN2, was tested as a solvent and template. C6H11BrN2 has a wide liquid range (despite being a solid at room temperature, with a melting point of 356 K), low vapour pressure and has been used extensively for ionothermal synthesis because it is a relatively polar solvent.

[Scheme 1]

The title compound, (C6H11N2)2[CdBr4], was obtained under ionothermal conditions using eminBr as the solvate. The SEM–EDS study of the title compound showed small amounts of a cadmium–manganese arsenate in the form of small needle-like crystals up to maximal 15 µm on the top of the plate-like crystals of the title compound (Fig. 1[link]). This phase is present in very small amounts and therefore could not be identified using powder or single-crystal X-ray diffraction techniques. The powder pattern indicated the tetra­gonal polymorph of the title compound as the main phase and the monoclinic polymorph (Gou et al., 2016[Gou, L., Liu, D., Zhao, K. & Yang, M. Y. (2016). Z. Kristallogr. New Cryst. Struct. 231, 271-272.]) as a minority phase.

[Figure 1]
Figure 1
Back-scattered scanning electromicrograph of leaf-like (C6H11N2)2[CdBr4]. The small needle-like crystals on the top are from an unidentified Cd/Mn arsenate.

2. Structural commentary

Emim, C6H11N2+, cations together with [CdBr4]2− anions as discrete tetra­hedra are the main structural building units (Fig. 2[link]). The imidazolium ring is, as expected, a planar, slightly distorted penta­gon. The deviation of the ring atoms from the least-squares plane is smaller than 0.006 (7) Å. The bond lengths of 1.356 (8) and 1.297 (7) Å for the N1—C1 and C1—N2 bonds, respectively, indicate conjugated double-bond character, having one bond slightly longer than the usual C=N double-bond length, 1.27 Å. The N1—C2 and N2—C3 bond lengths [1.360 (7) and 1.359 (8) Å] are shorter than a typical C—N single bond (1.472 ± 6 Å) and close to the shortened (partial double bond) in heterocyclic systems, 1.352 ± 5 Å, while the bond length of 1.373 (9) Å for C2—C3 is slightly longer than a typical C=C double bond of 1.337 ± 6 Å (Macgillavry & Rieck, 1968[Macgillavry, C. H. & Rieck, G. D. (1968). Editors. International Tables for X-ray crystallography, Vol. III, Physical and Chemical Tables, General editor: K. Lonsdale, pp. 273-285. Birmingham, England: IUCr, The Kynoch Press.]). The alkyl groups of the side chains showed strong anisotropic atomic displacements during refinement, suggesting a statistical positional disorder that was taken into account for the final model (Fig. 2[link]). The carbon atoms C4, C5, C6 and C7 from the disordered alkyl groups of side chains are also planar and the largest deviation from the least-squares plane through the imidazolium ring atoms is 0.163 (16) Å for C7 and −0.949 (19) Å for C6, while C5 and C4 are just −0.013 (1) and 0.039 (1) Å, respectively, out of plane.

[Figure 2]
Figure 2
A view of the mol­ecular entities in the structure of (C6H11N2)2[CdBr4]. Displacement ellipsoids are drawn at the 50% probability level. H atoms are represented as small spheres of arbitrary radius. C—H⋯Br hydrogen-bonding inter­actions are shown with dashed blue lines. Disordered alkyl groups are distinguished by solid and dotted bonds, together with the C and H atoms being shown in different colours. [Symmetry codes: (a) y − [{1\over 4}], −x + [{1\over 4}], −z + [{1\over 4}]; (b) −y + [{1\over 4}], x + [{1\over 4}], −z + [{1\over 4}]; (c) −x, −y + [{1\over 2}], z; (d) −y + [{3\over 4}], x + [{3\over 4}], −z + [{3\over 4}]; (e) y − [{3\over 4}], −x + [{3\over 4}], −z + [{3\over 4}]; (f) −x, −y + [{3\over 2}], z.]

Both unique Cd atoms occupy special positions (on a fourfold rotoinversion axis parallel to the c axis, site symmetry [\overline{4}]). Consequently both tetra­bromido­cadmate anions possess crystallographically imposed [\overline{4}] symmetry and therefore, each Cd atom bonds to four symmetry-related Br atoms (Fig. 2[link]). The Cd1—Br1 bond length of 2.5745 (6) Å in the almost regular tetra­hedral configuration of the [Cd1Br4]2− anion is slightly shorter than 2.5806 (5) Å for the [Cd2Br4]2− anion. The Br—Cd—Br bond angles are 109.14 (3) and 109.64 (2)° in [Cd1Br4]2− but 107.88 (1) and 112.71 (3)° in the slightly more distorted [Cd2Br4]2– anion. The angular range for both anions is comparable with those reported by Sharma et al. (2006[Sharma, R. P., Sharma, R., Bala, R., Salas, J. M. & Quiros, M. (2006). J. Mol. Struct. 794, 341-347.]).

3. Infrared spectroscopy

Fourier-transform infrared (FT–IR) absorption single-crystal infrared spectra were recorded on a Bruker Tensor 27 FT–IR spectrophotometer with a mid-IR glowbar light source and KBr beam splitter, attached to a Hyperion2000 FT–IR microscope with a liquid nitro­gen-cooled mid-IR broad band MCT detector. A total of 128 scans were accumulated between 4000 and 550 cm−1 using a circular sample aperture (100 µm diameter) and ATR 15 × objective.

The title compound shows characteristic bands of the imidazolium ring and the alkyl chains (Barbara, 2004[Barbara, S. (2004). In Infrared Spectroscopy: Fundamentals and Applications. New York: Wiley.]; Nakamoto, 1978[Nakamoto, K. (1978). In Infrared and Raman Spectra of Inorganic and Coordination Compounds. New York: Wiley.]) (Fig. 3[link]). The bands at 3134 and 3101 cm−1 can be attributed to aromatic C—H stretching (Tait & Osteryoung, 1984[Tait, S. & Osteryoung, R. A. (1984). Inorg. Chem. 23, 4352-4360.]). Their relatively low values confirm the presence of weak hydrogen bonds. A higher wave number would indicate a diminution or absence of hydrogen bonds (Larsen et al., 2000[Larsen, A. S., Holbrey, J. D., Tham, F. S. & Reed, C. A. (2000). J. Am. Chem. Soc. 122, 7264-7272.]). The band at 2985 cm−1 can be attributed to aliphatic C—H stretching (Tait & Osteryoung, 1984[Tait, S. & Osteryoung, R. A. (1984). Inorg. Chem. 23, 4352-4360.]); aliphatic C—H bending vibrations [δ(CH2), δ(CH3), δas(CH3)] are located between 1470 and 1380 cm−1 (Katsyuba et al., 2004[Katsyuba, S. A., Dyson, P. J., Vandyukova, E. E., Chernova, A. V. & Vidiš, A. (2004). Helv. Chim. Acta, 87, 2556-2565.]) and mostly represented by the band at 1460 cm−1. The band at 1578 cm−1 is assigned to the C=C and C—N stretching vibrations of the imidazolium ring. Bands centred at 1342 and 1162 cm−1, respectively, represent the stretching vibrations between the alkyl chains and N atoms (Katsyuba et al., 2004[Katsyuba, S. A., Dyson, P. J., Vandyukova, E. E., Chernova, A. V. & Vidiš, A. (2004). Helv. Chim. Acta, 87, 2556-2565.]). All bands below 850 cm−1 can be attributed to the out-of-plane vibrations of the imidazolium cation (Katsyuba et al., 2004[Katsyuba, S. A., Dyson, P. J., Vandyukova, E. E., Chernova, A. V. & Vidiš, A. (2004). Helv. Chim. Acta, 87, 2556-2565.]). The most intense bands are located at 854, 775 and 621 cm−1. Even if there is no water in the structure of (C6H11N2)2[CdBr4], O—H vibrations may still be present because of the hygroscopic character of the ionic liquid.

[Figure 3]
Figure 3
FT–IR spectrum of (C6H11N2)2[CdBr4].

4. Supra­molecular features

There are no significant inter­actions between [Cd2Br4]2– anions, except a short Br1⋯Br1 contact which amounts to 3.764 (2) Å. The crystal packing of the cations and anions in a three-dimensional network is realized through C—H⋯Br inter­actions (Figs. 2[link] and 4[link], Table 1[link]) involving the imidazolium ring H atoms (H1, H2 and H3), but not the H atoms of the alkyl side chains. Larsen et al. (2000[Larsen, A. S., Holbrey, J. D., Tham, F. S. & Reed, C. A. (2000). J. Am. Chem. Soc. 122, 7264-7272.]) found that the imidazolium cation is often disordered whereby the disorder can take many different forms. They also have found that positional disorder of the cations in their crystal structures is a direct indicator of packing inefficiency, i.e. packing inefficiency becomes reflected in disorder when cation/anion inter­actions are reduced essentially to the level of van der Waals or very weak hydrogen-bonding-type forces. The resulting network in the title structure has a channel structure defined by the organization of the imidazolium cations, with the [CdBr4]2– anions residing in the channels (Fig. 5[link]).

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
C1—H1⋯Br2i 0.93 2.77 3.679 (6) 167
C2—H2⋯Br1ii 0.93 2.93 3.824 (7) 161
C3—H3⋯Br1 0.93 2.90 3.753 (6) 154
Symmetry codes: (i) [-x+{\script{1\over 2}}, -y+{\script{3\over 2}}, -z+{\script{1\over 2}}]; (ii) [-y+{\script{3\over 4}}, x+{\script{1\over 4}}, z+{\script{1\over 4}}].
[Figure 4]
Figure 4
The packing of the structure of (C6H11N2)2[CdBr4], viewed down the a axis, showing the tetra­hedral [CdBr4]2− anions linked to the emim, [C6H11N2]+, cations by hydrogen-bonding inter­actions. C and N atoms are presented as black and blue spheres, respectively, and H atoms as grey small spheres.
[Figure 5]
Figure 5
The projection of the structure of (C6H11N2)2[CdBr4], viewed down the c axis, normal to the channels formed by the supra­molecular organization of the imidazolium cations.

5. Database survey

Tetragonal (C6H11N2)2[CdBr4] is isotypic with (C6H11N2)2[CoBr4] and (C6H11N2)2[NiBr4] (Hitchcock et al., 1993[Hitchcock, P. B., Seddon, K. R. & Welton, T. (1993). J. Chem. Soc. Dalton Trans. pp. 2639-2643.]), as well as (C6H11N2)2[ZnBr4] (Zhou et al., 2010[Zhou, W. W., Zhao, W., Song, M. J., Bao, X. & Wang, F. W. (2010). Z. Kristallogr. New Cryst. Struct. 225, 801-802.]; Zhang & Liu, 2012[Zhang, X. C. & Liu, B. (2012). Bull. Chem. Soc. Ethiop. 26, 407-414.]). However, these three structures do not show any disorder of the imidazolium cations. The crystal structure of the monoclinic (C6H11N2)2[CdBr4] polymorph has also been reported recently (Gou et al., 2016[Gou, L., Liu, D., Zhao, K. & Yang, M. Y. (2016). Z. Kristallogr. New Cryst. Struct. 231, 271-272.]).

6. Synthesis and crystallization

A 1 g mixture of CdO, Mn(NO3)2·H2O, As2O5 in the molar ratio 2:2:1 was mixed with 2 g of molten emimBr and placed in a teflon container into a steel autoclave. A heating regime with three steps was chosen: the autoclaves were heated from 293 to 493 K (four h), held at 493 K for 72 h, and finally cooled to room temperature within 99 h. The obtained products were washed with ethanol, filtered and dried in the air at room temperature. The title compound crystallized as leafy-like crystals (yield ca 85%) together with crystals of the monoclinic polymorph (yield ca 10%) and small amounts of a yet unidentified Cd/Mn-arsenate (single-crystal size 10 µm). The crystals of tetra­gonal (C6H11N2)2[CdBr4]) are no longer than 0.15 mm in length.

7. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2[link]. The imidazolium cation was modelled as disordered having approximate twofold rotation symmetry. The two orientations of the disordered cation are related to each other by a 180° rotation around the pseudo-twofold symmetry axis lying in the ring plane, connecting the C1 and bis­ecting the opposite C2—C3 bonds in the imidazolium ring. This causes a positional disorder of the methyl and ethyl side chains, with a site occupation ratio of 0.590 (11):0.410 (11). All hydrogen atoms attached to C atoms were placed in geometrically calculated positions and refined using a riding model, with C—H = 0.96 Å and Uiso(H) = 1.5Ueq(C) for methyl H atoms, C—H = 0.97 Å and Uiso(H) = 1.2Ueq(C) for methyl­ene H atoms, and C—H = 0.93 Å and Uiso(H) = 1.2Ueq(C) for imidazolium ring H atoms.

Table 2
Experimental details

Crystal data
Chemical formula (C6H11N2)2[CdBr4]
Mr 654.38
Crystal system, space group Tetragonal, I41/a
Temperature (K) 100
a, c (Å) 14.691 (2), 20.075 (4)
V3) 4332.8 (12)
Z 8
Radiation type Mo Kα
μ (mm−1) 8.39
Crystal size (mm) 0.15 × 0.02 × 0.01
 
Data collection
Diffractometer Stoe StadiVari with pixel array detector
Absorption correction Multi-scan (X-AREA and X-RED32; Stoe, 2013[Stoe (2013). X-AREA and X-RED32. Stoe & Cie, Darmstadt, Germany.])
Tmin, Tmax 0.366, 0.921
No. of measured, independent and observed [I > 2σ(I)] reflections 34206, 3016, 2046
Rint 0.102
(sin θ/λ)max−1) 0.694
 
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.037, 0.074, 0.96
No. of reflections 3016
No. of parameters 94
No. of restraints 17
H-atom treatment H-atom parameters constrained
Δρmax, Δρmin (e Å−3) 0.89, −0.86
Computer programs: X-AREA and X-RED32 (Stoe, 2013[Stoe (2013). X-AREA and X-RED32. Stoe & Cie, Darmstadt, Germany.]), SIR97 (Altomare et al., 1999[Altomare, A., Burla, M. C., Camalli, M., Cascarano, G. L., Giacovazzo, C., Guagliardi, A., Moliterni, A. G. G., Polidori, G. & Spagna, R. (1999). J. Appl. Cryst. 32, 115-119.]), SHELXL2014 (Sheldrick, 2015[Sheldrick, G. M. (2015). Acta Cryst. C71, 3-8.]), WinGX (Farrugia, 2012[Farrugia, L. J. (2012). J. Appl. Cryst. 45, 849-854.]), ATOMS (Dowty, 2000[Dowty, E. (2000). ATOMS for Windows. Shape Software, Kingsport, Tennessee, USA.]) and publCIF (Westrip, 2010[Westrip, S. P. (2010). J. Appl. Cryst. 43, 920-925.]).

Supporting information


Computing details top

Data collection: X-AREA (Stoe, 2013); cell refinement: X-AREA (Stoe, 2013); data reduction: X-RED (Stoe, 2013); program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015) and WinGX (Farrugia, 2012); molecular graphics: ATOMS (Dowty, 2000); software used to prepare material for publication: publCIF (Westrip, 2010).

Bis(1-ethyl-3-methylimidazolium) tetrabromidocadmate(II) top
Crystal data top
(C6H11N2)2[CdBr4]Dx = 2.006 Mg m3
Mr = 654.38Mo Kα radiation, λ = 0.71073 Å
Tetragonal, I41/aCell parameters from 18051 reflections
a = 14.691 (2) Åθ = 5.6–63.4°
c = 20.075 (4) ŵ = 8.39 mm1
V = 4332.8 (12) Å3T = 100 K
Z = 8Leaf-like, colourless
F(000) = 24800.15 × 0.02 × 0.01 mm
Data collection top
Stoe StadiVari with pixel array detector
diffractometer
3016 independent reflections
Radiation source: IµS microfocus source2046 reflections with I > 2σ(I)
Plane graphite monochromatorRint = 0.102
φ and ω scansθmax = 29.6°, θmin = 2.8°
Absorption correction: multi-scan
(X-AREA and X-RED; Stoe, 2013)
h = 1720
Tmin = 0.366, Tmax = 0.921k = 1220
34206 measured reflectionsl = 2727
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.037Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.074H-atom parameters constrained
S = 0.96 w = 1/[σ2(Fo2) + (0.0344P)2]
where P = (Fo2 + 2Fc2)/3
3016 reflections(Δ/σ)max = 0.001
94 parametersΔρmax = 0.89 e Å3
17 restraintsΔρmin = 0.86 e Å3
Special details top

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > 2sigma(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/UeqOcc. (<1)
Cd10.00000.25000.12500.02409 (13)
Cd20.00000.75000.37500.02503 (13)
Br10.00834 (3)0.39254 (4)0.05065 (3)0.04833 (17)
Br20.12129 (4)0.66831 (3)0.30377 (3)0.03715 (13)
N10.3058 (3)0.5397 (3)0.2191 (3)0.0513 (12)
N20.1979 (3)0.5755 (3)0.1517 (3)0.0505 (12)
C10.2669 (4)0.6082 (4)0.1840 (3)0.0464 (13)
H10.28640.66850.18320.056*
C20.2585 (4)0.4620 (4)0.2067 (3)0.0526 (14)
H20.27080.40440.22370.063*
C30.1891 (4)0.4850 (4)0.1641 (3)0.0501 (14)
H30.14470.44630.14710.060*
C40.38352 (8)0.54777 (5)0.26324 (6)0.073 (2)
H410.39570.49000.28390.109*0.590 (11)
H420.37100.59230.29700.109*0.590 (11)
H430.43620.56640.23810.109*0.590 (11)
H4A0.39120.48900.28450.087*0.410 (11)
H4B0.43640.55740.23550.087*0.410 (11)
C50.13928 (7)0.62737 (8)0.11001 (5)0.090 (3)
H510.09140.58880.09260.136*0.410 (11)
H520.17210.65360.07380.136*0.410 (11)
H530.11100.67560.13570.136*0.410 (11)
H5A0.13000.59090.07030.109*0.590 (11)
H5B0.08210.63120.13240.109*0.590 (11)
C60.3888 (12)0.6105 (11)0.3126 (9)0.0660.410 (11)
H610.44580.60400.33560.099*0.410 (11)
H620.33960.60160.34330.099*0.410 (11)
H630.38490.67050.29380.099*0.410 (11)
C70.1525 (10)0.7140 (9)0.0898 (8)0.0850.590 (11)
H710.11010.72850.05500.127*0.590 (11)
H720.21350.72060.07330.127*0.590 (11)
H730.14340.75460.12670.127*0.590 (11)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cd10.02423 (18)0.02423 (18)0.0238 (3)0.0000.0000.000
Cd20.02750 (19)0.02750 (19)0.0201 (3)0.0000.0000.000
Br10.0365 (3)0.0530 (3)0.0555 (3)0.0060 (2)0.0071 (2)0.0323 (3)
Br20.0464 (3)0.0296 (2)0.0354 (3)0.00354 (19)0.0193 (2)0.00600 (19)
N10.048 (3)0.055 (3)0.051 (3)0.016 (2)0.014 (2)0.005 (2)
N20.056 (3)0.050 (3)0.045 (3)0.008 (2)0.013 (2)0.017 (2)
C10.053 (3)0.041 (3)0.045 (3)0.010 (2)0.024 (3)0.009 (2)
C20.052 (4)0.046 (3)0.060 (4)0.010 (3)0.008 (3)0.003 (3)
C30.060 (4)0.039 (3)0.051 (4)0.009 (2)0.009 (3)0.015 (3)
C40.060 (4)0.079 (5)0.079 (5)0.039 (4)0.013 (4)0.020 (4)
C50.135 (8)0.054 (4)0.082 (6)0.022 (4)0.028 (5)0.001 (4)
C60.0650.0540.0790.0170.0220.008
C70.0810.0590.1150.0220.0510.046
Geometric parameters (Å, º) top
Cd1—Br1i2.5745 (6)C4—H420.9596 (11)
Cd1—Br1ii2.5745 (6)C4—H430.9633 (8)
Cd1—Br12.5745 (6)C4—H4A0.9691 (8)
Cd1—Br1iii2.5745 (6)C4—H4B0.9666 (8)
Cd2—Br2iv2.5806 (5)C5—C71.350 (11)
Cd2—Br2v2.5806 (5)C5—H510.9681 (8)
Cd2—Br22.5806 (5)C5—H520.9543 (10)
Cd2—Br2vi2.5806 (5)C5—H530.9706 (9)
N1—C11.356 (8)C5—H5A0.9700 (8)
N1—C21.360 (7)C5—H5B0.9552 (8)
N1—C41.450 (6)C6—H420.488 (16)
N2—C11.297 (7)C6—H610.9600
N2—C31.359 (8)C6—H620.9600
N2—C51.421 (6)C6—H630.9600
C1—H10.9300C7—H520.987 (16)
C2—C31.373 (9)C7—H531.241 (15)
C2—H20.9300C7—H710.9600
C3—H30.9300C7—H720.9600
C4—C61.355 (18)C7—H730.9600
C4—H410.9610 (8)
Br1i—Cd1—Br1ii109.14 (3)H4A—C4—H4B106.88 (8)
Br1i—Cd1—Br1109.638 (17)C7—C5—N2126.5 (5)
Br1ii—Cd1—Br1109.638 (17)C7—C5—H51123.3 (5)
Br1i—Cd1—Br1iii109.638 (17)N2—C5—H51109.8 (2)
Br1ii—Cd1—Br1iii109.638 (17)C7—C5—H5246.9 (8)
Br1—Cd1—Br1iii109.14 (3)N2—C5—H52111.0 (2)
Br2iv—Cd2—Br2v112.71 (3)H51—C5—H52109.27 (10)
Br2iv—Cd2—Br2107.878 (14)C7—C5—H5362.1 (8)
Br2v—Cd2—Br2107.878 (14)N2—C5—H53109.7 (2)
Br2iv—Cd2—Br2vi107.878 (14)H51—C5—H53107.93 (9)
Br2v—Cd2—Br2vi107.878 (14)H52—C5—H53109.06 (12)
Br2—Cd2—Br2vi112.71 (3)C7—C5—H5A107.1 (7)
C1—N1—C2108.3 (5)N2—C5—H5A105.9 (2)
C1—N1—C4126.1 (4)H51—C5—H5A43.85 (3)
C2—N1—C4125.7 (5)H52—C5—H5A70.62 (6)
C1—N2—C3110.2 (6)H53—C5—H5A141.27 (15)
C1—N2—C5124.7 (5)C7—C5—H5B102.3 (8)
C3—N2—C5125.1 (5)N2—C5—H5B106.7 (2)
N2—C1—N1108.3 (5)H51—C5—H5B64.21 (5)
N2—C1—H1125.8H52—C5—H5B141.30 (18)
N1—C1—H1125.8H53—C5—H5B47.87 (4)
N1—C2—C3106.6 (6)H5A—C5—H5B107.23 (8)
N1—C2—H2126.7C4—C6—H4229.2 (17)
C3—C2—H2126.7C4—C6—H61109.5
N2—C3—C2106.6 (5)H42—C6—H61136.1
N2—C3—H3126.7C4—C6—H62109.5
C2—C3—H3126.7H42—C6—H6286.2
C6—C4—N1123.2 (8)H61—C6—H62109.5
C6—C4—H41105.9 (7)C4—C6—H63109.5
N1—C4—H41109.7 (2)H42—C6—H63102.6
C6—C4—H4214.4 (8)H61—C6—H63109.5
N1—C4—H42109.7 (2)H62—C6—H63109.5
H41—C4—H42109.44 (11)C5—C7—H5244.9 (4)
C6—C4—H4398.2 (8)C5—C7—H5343.7 (4)
N1—C4—H43109.6 (2)H52—C7—H5388.7 (8)
H41—C4—H43109.13 (9)C5—C7—H71109.5
H42—C4—H43109.23 (11)H52—C7—H7198.7
C6—C4—H4A106.1 (7)H53—C7—H71108.7
N1—C4—H4A106.8 (2)C5—C7—H72109.5
H41—C4—H4A3.993 (3)H52—C7—H7272.9
H42—C4—H4A108.60 (11)H53—C7—H72139.5
H43—C4—H4A112.92 (9)H71—C7—H72109.5
C6—C4—H4B106.0 (8)C5—C7—H73109.5
N1—C4—H4B106.9 (2)H52—C7—H73148.2
H41—C4—H4B103.25 (8)H53—C7—H7368.9
H42—C4—H4B117.45 (12)H71—C7—H73109.5
H43—C4—H4B8.460 (7)H72—C7—H73109.5
C3—N2—C1—N10.2 (6)C5—N2—C3—C2179.7 (4)
C5—N2—C1—N1179.1 (4)N1—C2—C3—N20.8 (6)
C2—N1—C1—N20.7 (6)C1—N1—C4—C651.2 (10)
C4—N1—C1—N2178.3 (4)C2—N1—C4—C6127.6 (10)
C1—N1—C2—C30.9 (6)C1—N2—C5—C710.0 (12)
C4—N1—C2—C3178.0 (4)C3—N2—C5—C7170.9 (11)
C1—N2—C3—C20.4 (6)
Symmetry codes: (i) y1/4, x+1/4, z+1/4; (ii) y+1/4, x+1/4, z+1/4; (iii) x, y+1/2, z; (iv) y+3/4, x+3/4, z+3/4; (v) y3/4, x+3/4, z+3/4; (vi) x, y+3/2, z.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C1—H1···Br2vii0.932.773.679 (6)167
C2—H2···Br1viii0.932.933.824 (7)161
C3—H3···Br10.932.903.753 (6)154
Symmetry codes: (vii) x+1/2, y+3/2, z+1/2; (viii) y+3/4, x+1/4, z+1/4.
 

Acknowledgements

The authors gratefully acknowledge financial support by the Austrian Science Foundation (FWF) (grant No. V203-N19) and the Ministry of Education, Science and Technological Development of the Republic of Serbia (grant No. III45007). The authors are also thankful to Dr Martin Ende for assisting during the low-temperature single-crystal X-ray measurement.

References

First citationAltomare, A., Burla, M. C., Camalli, M., Cascarano, G. L., Giacovazzo, C., Guagliardi, A., Moliterni, A. G. G., Polidori, G. & Spagna, R. (1999). J. Appl. Cryst. 32, 115–119.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationBarbara, S. (2004). In Infrared Spectroscopy: Fundamentals and Applications. New York: Wiley.  Google Scholar
First citationDowty, E. (2000). ATOMS for Windows. Shape Software, Kingsport, Tennessee, USA.  Google Scholar
First citationFarrugia, L. J. (2012). J. Appl. Cryst. 45, 849–854.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationGou, L., Liu, D., Zhao, K. & Yang, M. Y. (2016). Z. Kristallogr. New Cryst. Struct. 231, 271–272.  CAS Google Scholar
First citationHitchcock, P. B., Seddon, K. R. & Welton, T. (1993). J. Chem. Soc. Dalton Trans. pp. 2639–2643.  CSD CrossRef Web of Science Google Scholar
First citationKatsyuba, S. A., Dyson, P. J., Vandyukova, E. E., Chernova, A. V. & Vidiš, A. (2004). Helv. Chim. Acta, 87, 2556–2565.  CrossRef CAS Google Scholar
First citationLarsen, A. S., Holbrey, J. D., Tham, F. S. & Reed, C. A. (2000). J. Am. Chem. Soc. 122, 7264–7272.  Web of Science CSD CrossRef CAS Google Scholar
First citationMacgillavry, C. H. & Rieck, G. D. (1968). Editors. International Tables for X-ray crystallography, Vol. III, Physical and Chemical Tables, General editor: K. Lonsdale, pp. 273–285. Birmingham, England: IUCr, The Kynoch Press.  Google Scholar
First citationMorris, R. E. (2009). Chem. Commun. pp. 2990–2998.  Web of Science CrossRef Google Scholar
First citationNakamoto, K. (1978). In Infrared and Raman Spectra of Inorganic and Coordination Compounds. New York: Wiley.  Google Scholar
First citationSharma, R. P., Sharma, R., Bala, R., Salas, J. M. & Quiros, M. (2006). J. Mol. Struct. 794, 341–347.  CSD CrossRef CAS Google Scholar
First citationSheldrick, G. M. (2015). Acta Cryst. C71, 3–8.  Web of Science CrossRef IUCr Journals Google Scholar
First citationStoe (2013). X-AREA and X-RED32. Stoe & Cie, Darmstadt, Germany.  Google Scholar
First citationTait, S. & Osteryoung, R. A. (1984). Inorg. Chem. 23, 4352–4360.  CrossRef CAS Google Scholar
First citationWestrip, S. P. (2010). J. Appl. Cryst. 43, 920–925.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationZhang, X. C. & Liu, B. (2012). Bull. Chem. Soc. Ethiop. 26, 407–414.  CrossRef Google Scholar
First citationZhou, W. W., Zhao, W., Song, M. J., Bao, X. & Wang, F. W. (2010). Z. Kristallogr. New Cryst. Struct. 225, 801–802.  CAS Google Scholar

This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Follow Acta Cryst. E
Sign up for e-alerts
Follow Acta Cryst. on Twitter
Follow us on facebook
Sign up for RSS feeds