supplementary materials


bx2429 scheme

Acta Cryst. (2012). E68, m1499    [ doi:10.1107/S1600536812046788 ]

Bis(2,4-dimethylpyridinium) tetrabromidomercurate(II)

R. Al-Far, S. F. Haddad and B. F. Ali

Abstract top

The asymmetric unit of the title compound, (C7H10N)2[HgBr4], consists of one cation and one half-anion, bisected by a twofold rotation axis passing through the metal atom. The anion exhibits a distorted tetrahedral arrangement about the HgII atom. In the crystal, the cations and anions are linked by N-H...Br hydrogen-bonding interactions along [010]. Cation-cation [pi]-[pi] stacking and Br...Br intermolecular interactions are absent.

Comment top

Noncovalent interactions play an important role in organizing structural units in both natural and artificial systems (Desiraju, 1997). In connection with ongoing studies (Al-Far & Ali 2007; Ali & Al-Far 2007; Ali et al., 2008) of the structural aspects of bromometal anions salts, we herein report the crystal structure of the title compound, (I).

In the title compound, Fig. 1, the asymmetric unit of the title compound, (C7H10N)2[HgBr4], consists of one cation and one half-anion, bisected by a twofold rotation axis passing through the metal center. The anion exhibits a distorted tetrahedral arrangement about the Hg atom (Table 1). The Hg—Br1 and the symmetry related one [2.5767 (11)Å] bonds are almost invariant and significantly shorter than Hg—Br2 and symmetry related one [2.6160 (11)Å]. These lengths fall within the range of Hg—Br distances reported previously for compounds containing [HgBr4]2- anions (Gowda et al., 2009; Li et al. 2009). It is noteworthy that the longer Hg—Br2 and the symmetry related bonds are involved in more and shorter interactions than the shorter bonds (Table 1). In the cation, the bond lengths and angles are in accordance with normal values (Allen et al., 1987). In the crystal structure the cations and anions are linked by N—H···Br hydrogen bonding interactions, Fig.2 along [010] direction. Cation···cation π···π stacking and Br···Br intermolecular interactions are absent.

Related literature top

For intermolecular interactions, see: Desiraju (1997). For related structures, see: Al-Far & Ali (2007); Ali & Al-Far (2007); Ali et al. (2008). For structures containing the [HgBr4]2- anion, see: Gowda et al. (2009); Li et al. (2009). For standard bond lengths in the cation, see: Allen et al. (1987).

Experimental top

A warm solution (40°C) of HgCl2 (1.0 mmol) dissolved in ethanol (10 ml; 95%), was added drop wise to a stirred hot solution of 2,4-dimethylpyridine (1 mmol) dissolved in ethanol (10 ml; 95%) and HBr (60%, 1 ml). During reflux for 2 h, liquid Br2 (1 ml) was added to the mixture. The final mixture was allowed to stand undisturbed at room temperature. Colorless crystals of the title salt formed in two days, filtered off and one crystal suitable for diffraction measurements is used to collect data.

Refinement top

All H atoms were positioned geometrically and refined using a riding model, with N—H = 0.86 Å and C—H = 0.93 and 0.96 Å, for aryl and methyl H-atoms, respectively. The Uiso(H) were allowed at 1.5Ueq(C methyl) or 1.2Ueq(N/C non-methyl).

Computing details top

Data collection: CrysAlis PRO (Agilent, 2011); cell refinement: CrysAlis PRO (Agilent, 2011); data reduction: CrysAlis PRO (Agilent, 2011); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. Molecular configuration and atom naming scheme for the title compound. Displacement ellipsoids are drawn at the 30% probability level. Symmetry operation (A) stands for -x + 1, y, -z + 3/2.
[Figure 2] Fig. 2. Packing diagram of the title compound, down crystallographic c axis. Interspecies hydrogen bonds are shown as dashed lines (N—HBr). Symmetry code (i) : x, -y, z+1/2.
Bis(2,4-dimethylpyridinium) tetrabromidomercurate(II) top
Crystal data top
(C7H10N)2[HgBr4]F(000) = 1352
Mr = 736.51Dx = 2.288 Mg m3
Monoclinic, C2/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2ycCell parameters from 1281 reflections
a = 20.022 (5) Åθ = 2.9–29.1°
b = 7.7985 (9) ŵ = 14.67 mm1
c = 17.651 (3) ÅT = 293 K
β = 129.12 (3)°Block, colourless
V = 2138.1 (11) Å30.44 × 0.40 × 0.18 mm
Z = 4
Data collection top
Agilent Xcalibur Eos
diffractometer
2895 independent reflections
Radiation source: Enhance (Mo) X-ray Source1454 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.036
Detector resolution: 16.0534 pixels mm-1θmax = 29.2°, θmin = 2.9°
ω scansh = 2726
Absorption correction: multi-scan
(CrysAlis PRO; Agilent, 2011)
k = 610
Tmin = 0.002, Tmax = 0.072l = 2416
5366 measured reflections
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)] = 0.050Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.102H-atom parameters constrained
S = 1.01 w = 1/[σ2(Fo2) + (0.0354P)2]
where P = (Fo2 + 2Fc2)/3
2895 reflections(Δ/σ)max < 0.001
98 parametersΔρmax = 1.45 e Å3
0 restraintsΔρmin = 1.54 e Å3
Crystal data top
(C7H10N)2[HgBr4]V = 2138.1 (11) Å3
Mr = 736.51Z = 4
Monoclinic, C2/cMo Kα radiation
a = 20.022 (5) ŵ = 14.67 mm1
b = 7.7985 (9) ÅT = 293 K
c = 17.651 (3) Å0.44 × 0.40 × 0.18 mm
β = 129.12 (3)°
Data collection top
Agilent Xcalibur Eos
diffractometer
2895 independent reflections
Absorption correction: multi-scan
(CrysAlis PRO; Agilent, 2011)
1454 reflections with I > 2σ(I)
Tmin = 0.002, Tmax = 0.072Rint = 0.036
5366 measured reflectionsθmax = 29.2°
Refinement top
R[F2 > 2σ(F2)] = 0.050H-atom parameters constrained
wR(F2) = 0.102Δρmax = 1.45 e Å3
S = 1.01Δρmin = 1.54 e Å3
2895 reflectionsAbsolute structure: ?
98 parametersFlack parameter: ?
0 restraintsRogers parameter: ?
Special details top

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s 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 > σ(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*/Ueq
Hg10.50000.17233 (6)0.75000.0544 (2)
Br10.54606 (6)0.33656 (12)0.90297 (6)0.0647 (3)
N10.3078 (5)0.0541 (10)0.9729 (5)0.066 (2)
H1A0.33430.03961.03420.080*
C10.3507 (5)0.1249 (10)0.9458 (6)0.050 (2)
Br20.36889 (6)0.01976 (14)0.69426 (7)0.0796 (4)
C20.3064 (5)0.1449 (10)0.8472 (6)0.053 (2)
H2A0.33480.19150.82600.064*
C30.2217 (6)0.0982 (11)0.7793 (6)0.054 (2)
C40.1817 (6)0.0263 (12)0.8122 (7)0.076 (3)
H4A0.12440.00760.76770.091*
C50.2249 (6)0.0046 (14)0.9087 (7)0.086 (3)
H5A0.19760.04430.93080.103*
C60.4414 (6)0.1759 (12)1.0245 (6)0.078 (3)
H6A0.44330.26241.06460.116*
H6B0.46580.22050.99610.116*
H6C0.47390.07771.06390.116*
C70.1732 (6)0.1298 (12)0.6723 (6)0.078 (3)
H7A0.12940.04380.63510.118*
H7B0.21220.12470.65810.118*
H7C0.14680.24110.65530.118*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Hg10.0559 (3)0.0639 (4)0.0459 (3)0.0000.0334 (2)0.000
Br10.0707 (6)0.0762 (8)0.0504 (5)0.0070 (5)0.0398 (5)0.0130 (5)
N10.066 (5)0.079 (6)0.057 (5)0.005 (4)0.040 (4)0.015 (4)
C10.058 (6)0.044 (6)0.055 (5)0.001 (4)0.039 (5)0.001 (4)
Br20.0820 (7)0.1058 (9)0.0702 (6)0.0375 (6)0.0572 (6)0.0225 (6)
C20.057 (6)0.056 (6)0.053 (5)0.003 (4)0.038 (5)0.002 (4)
C30.059 (6)0.041 (5)0.052 (5)0.003 (4)0.030 (5)0.000 (4)
C40.050 (6)0.084 (8)0.065 (6)0.012 (5)0.023 (5)0.011 (6)
C50.058 (7)0.111 (10)0.087 (8)0.005 (6)0.046 (6)0.029 (7)
C60.053 (6)0.100 (9)0.064 (6)0.012 (5)0.030 (5)0.003 (6)
C70.078 (7)0.087 (8)0.053 (5)0.013 (6)0.033 (5)0.010 (5)
Geometric parameters (Å, º) top
Hg1—Br12.5767 (11)C3—C41.372 (12)
Hg1—Br1i2.5767 (10)C3—C71.502 (11)
Hg1—Br22.6160 (11)C4—C51.349 (11)
Hg1—Br2i2.6160 (11)C4—H4A0.9300
N1—C11.338 (9)C5—H5A0.9300
N1—C51.347 (10)C6—H6A0.9600
N1—H1A0.8600C6—H6B0.9600
C1—C21.376 (10)C6—H6C0.9600
C1—C61.485 (11)C7—H7A0.9600
C2—C31.372 (10)C7—H7B0.9600
C2—H2A0.9300C7—H7C0.9600
Br1—Hg1—Br1i120.39 (5)C5—C4—C3120.4 (9)
Br1—Hg1—Br2106.83 (4)C5—C4—H4A119.8
Br1i—Hg1—Br2106.25 (5)C3—C4—H4A119.8
Br1—Hg1—Br2i106.25 (5)N1—C5—C4119.6 (9)
Br1i—Hg1—Br2i106.83 (4)N1—C5—H5A120.2
Br2—Hg1—Br2i110.13 (6)C4—C5—H5A120.2
C1—N1—C5123.1 (8)C1—C6—H6A109.5
C1—N1—H1A118.5C1—C6—H6B109.5
C5—N1—H1A118.5H6A—C6—H6B109.5
N1—C1—C2116.9 (8)C1—C6—H6C109.5
N1—C1—C6117.3 (8)H6A—C6—H6C109.5
C2—C1—C6125.8 (8)H6B—C6—H6C109.5
C3—C2—C1122.0 (8)C3—C7—H7A109.5
C3—C2—H2A119.0C3—C7—H7B109.5
C1—C2—H2A119.0H7A—C7—H7B109.5
C2—C3—C4118.0 (8)C3—C7—H7C109.5
C2—C3—C7121.2 (8)H7A—C7—H7C109.5
C4—C3—C7120.8 (9)H7B—C7—H7C109.5
C5—N1—C1—C20.5 (13)C1—C2—C3—C7176.6 (7)
C5—N1—C1—C6179.1 (9)C2—C3—C4—C50.6 (15)
N1—C1—C2—C31.3 (12)C7—C3—C4—C5177.4 (9)
C6—C1—C2—C3178.3 (8)C1—N1—C5—C40.1 (15)
C1—C2—C3—C41.4 (13)C3—C4—C5—N10.1 (16)
Symmetry code: (i) x+1, y, z+3/2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1A···Br2ii0.862.453.286 (7)163
Symmetry code: (ii) x, y, z+1/2.
Selected bond lengths (Å) top
Hg1—Br12.5767 (11)Hg1—Br22.6160 (11)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1A···Br2i0.862.453.286 (7)163.3
Symmetry code: (i) x, y, z+1/2.
Acknowledgements top

The structure was determined at the Hamdi Mango Center for Scientific Research at the University of Jordan, Amman, Jordan. RA-F would like to thank Al-Balqa'a Applied University (Jordan) for financial support (sabbatical leave).

references
References top

Agilent (2011). CrysAlis PRO. Agilent Technologies, Yarnton, England.

Al-Far, R. & Ali, B. F. (2007). Acta Cryst. C63, m137–m139.

Ali, B. F. & Al-Far, R. (2007). Acta Cryst. C63, m451–m453.

Ali, B. F., Al-Far, R. H. & Haddad, S. F. (2008). Acta Cryst. E64, m751–m752.

Allen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1–19.

Desiraju, G. R. (1997). Chem. Commun. pp. 1475–1482.

Gowda, B. T., Foro, S., Terao, H. & Fuess, H. (2009). Acta Cryst. E65, m946.

Li, S.-J., Chen, A.-H., Zheng, Z.-Y., Liu, S.-W. & Liu, Q.-X. (2009). Acta Cryst. E65, m1652.

Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122.