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

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

doi:10.1107/S1600536812046788

metal-organic compounds

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 68| Part 12| December 2012| Page m1499

doi:10.1107/S1600536812046788

Open

access

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

Rawhi Al-Far,^a Salim F. Haddad ^b and Basem F. Ali ^c ^*

^aFaculty of Science and IT, Al-Balqa'a Applied University, Salt, Jordan, ^bDepartment of Chemistry, The University of Jordan, Amman 11942, Jordan, and ^cDepartment of Chemistry, Al al-Bayt University, Mafraq 25113, Jordan
^*Correspondence e-mail: bfali@aabu.edu.jo

(Received 6 November 2012; accepted 13 November 2012; online 17 November 2012)

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 Hg^II atom. In the crystal, the cations and anions are linked by N—H⋯Br hydrogen-bonding interactions along [010]. Cation–cation π–π stacking and Br⋯Br intermolecular interactions are absent.

Related literature

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

Crystal data

(C₇H₁₀N)₂[HgBr₄]
M_r = 736.51
Monoclinic, C 2/c
a = 20.022 (5) Å
b = 7.7985 (9) Å
c = 17.651 (3) Å
β = 129.12 (3)°
V = 2138.1 (11) Å³
Z = 4
Mo Kα radiation
μ = 14.67 mm⁻¹
T = 293 K
0.44 × 0.40 × 0.18 mm

Data collection

Agilent Xcalibur Eos diffractometer
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2011 ) T_min = 0.002, T_max = 0.072
5366 measured reflections
2895 independent reflections
1454 reflections with I > 2σ(I)
R_int = 0.036

Refinement

R[F² > 2σ(F²)] = 0.050
wR(F²) = 0.102
S = 1.01
2895 reflections
98 parameters
H-atom parameters constrained
Δρ_max = 1.45 e Å⁻³
Δρ_min = −1.54 e Å⁻³

Table 1
Selected bond lengths (Å)

Hg1—Br1	2.5767 (11)
Hg1—Br2	2.6160 (11)

Table 2
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1A⋯Br2ⁱ	0.86	2.45	3.286 (7)	163
Symmetry code: (i) $[x, -y, z+{\script{1\over 2}}]$ .

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

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536812046788/bx2429sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536812046788/bx2429Isup2.hkl

checkCIF report

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.

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

	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.
	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
M_r = 736.51	D_x = 2.288 Mg m⁻³
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yc	Cell parameters from 1281 reflections
a = 20.022 (5) Å	θ = 2.9–29.1°
b = 7.7985 (9) Å	µ = 14.67 mm⁻¹
c = 17.651 (3) Å	T = 293 K
β = 129.12 (3)°	Block, colourless
V = 2138.1 (11) Å³	0.44 × 0.40 × 0.18 mm
Z = 4

Data collection top

Agilent Xcalibur Eos diffractometer	2895 independent reflections
Radiation source: Enhance (Mo) X-ray Source	1454 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.036
Detector resolution: 16.0534 pixels mm^-1	θ_max = 29.2°, θ_min = 2.9°
ω scans	h = −27→26
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2011)	k = −6→10
T_min = 0.002, T_max = 0.072	l = −24→16
5366 measured reflections

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.050	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.102	H-atom parameters constrained
S = 1.01	w = 1/[σ²(F_o²) + (0.0354P)²] where P = (F_o² + 2F_c²)/3
2895 reflections	(Δ/σ)_max < 0.001
98 parameters	Δρ_max = 1.45 e Å⁻³
0 restraints	Δρ_min = −1.54 e Å⁻³

Crystal data top

(C₇H₁₀N)₂[HgBr₄]	V = 2138.1 (11) Å³
M_r = 736.51	Z = 4
Monoclinic, C2/c	Mo Kα radiation
a = 20.022 (5) Å	µ = 14.67 mm⁻¹
b = 7.7985 (9) Å	T = 293 K
c = 17.651 (3) Å	0.44 × 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)
T_min = 0.002, T_max = 0.072	R_int = 0.036
5366 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.050	0 restraints
wR(F²) = 0.102	H-atom parameters constrained
S = 1.01	Δρ_max = 1.45 e Å⁻³
2895 reflections	Δρ_min = −1.54 e Å⁻³
98 parameters

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

	x	y	z	U_iso*/U_eq
Hg1	0.5000	0.17233 (6)	0.7500	0.0544 (2)
Br1	0.54606 (6)	0.33656 (12)	0.90297 (6)	0.0647 (3)
N1	0.3078 (5)	0.0541 (10)	0.9729 (5)	0.066 (2)
H1A	0.3343	0.0396	1.0342	0.080*
C1	0.3507 (5)	0.1249 (10)	0.9458 (6)	0.050 (2)
Br2	0.36889 (6)	−0.01976 (14)	0.69426 (7)	0.0796 (4)
C2	0.3064 (5)	0.1449 (10)	0.8472 (6)	0.053 (2)
H2A	0.3348	0.1915	0.8260	0.064*
C3	0.2217 (6)	0.0982 (11)	0.7793 (6)	0.054 (2)
C4	0.1817 (6)	0.0263 (12)	0.8122 (7)	0.076 (3)
H4A	0.1244	−0.0076	0.7677	0.091*
C5	0.2249 (6)	0.0046 (14)	0.9087 (7)	0.086 (3)
H5A	0.1976	−0.0443	0.9308	0.103*
C6	0.4414 (6)	0.1759 (12)	1.0245 (6)	0.078 (3)
H6A	0.4433	0.2624	1.0646	0.116*
H6B	0.4658	0.2205	0.9961	0.116*
H6C	0.4739	0.0777	1.0639	0.116*
C7	0.1732 (6)	0.1298 (12)	0.6723 (6)	0.078 (3)
H7A	0.1294	0.0438	0.6351	0.118*
H7B	0.2122	0.1247	0.6581	0.118*
H7C	0.1468	0.2411	0.6553	0.118*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Hg1	0.0559 (3)	0.0639 (4)	0.0459 (3)	0.000	0.0334 (2)	0.000
Br1	0.0707 (6)	0.0762 (8)	0.0504 (5)	−0.0070 (5)	0.0398 (5)	−0.0130 (5)
N1	0.066 (5)	0.079 (6)	0.057 (5)	0.005 (4)	0.040 (4)	0.015 (4)
C1	0.058 (6)	0.044 (6)	0.055 (5)	0.001 (4)	0.039 (5)	−0.001 (4)
Br2	0.0820 (7)	0.1058 (9)	0.0702 (6)	−0.0375 (6)	0.0572 (6)	−0.0225 (6)
C2	0.057 (6)	0.056 (6)	0.053 (5)	−0.003 (4)	0.038 (5)	−0.002 (4)
C3	0.059 (6)	0.041 (5)	0.052 (5)	0.003 (4)	0.030 (5)	0.000 (4)
C4	0.050 (6)	0.084 (8)	0.065 (6)	−0.012 (5)	0.023 (5)	0.011 (6)
C5	0.058 (7)	0.111 (10)	0.087 (8)	0.005 (6)	0.046 (6)	0.029 (7)
C6	0.053 (6)	0.100 (9)	0.064 (6)	−0.012 (5)	0.030 (5)	−0.003 (6)
C7	0.078 (7)	0.087 (8)	0.053 (5)	0.013 (6)	0.033 (5)	0.010 (5)

Geometric parameters (Å, º) top

Hg1—Br1	2.5767 (11)	C3—C4	1.372 (12)
Hg1—Br1ⁱ	2.5767 (10)	C3—C7	1.502 (11)
Hg1—Br2	2.6160 (11)	C4—C5	1.349 (11)
Hg1—Br2ⁱ	2.6160 (11)	C4—H4A	0.9300
N1—C1	1.338 (9)	C5—H5A	0.9300
N1—C5	1.347 (10)	C6—H6A	0.9600
N1—H1A	0.8600	C6—H6B	0.9600
C1—C2	1.376 (10)	C6—H6C	0.9600
C1—C6	1.485 (11)	C7—H7A	0.9600
C2—C3	1.372 (10)	C7—H7B	0.9600
C2—H2A	0.9300	C7—H7C	0.9600

Br1—Hg1—Br1ⁱ	120.39 (5)	C5—C4—C3	120.4 (9)
Br1—Hg1—Br2	106.83 (4)	C5—C4—H4A	119.8
Br1ⁱ—Hg1—Br2	106.25 (5)	C3—C4—H4A	119.8
Br1—Hg1—Br2ⁱ	106.25 (5)	N1—C5—C4	119.6 (9)
Br1ⁱ—Hg1—Br2ⁱ	106.83 (4)	N1—C5—H5A	120.2
Br2—Hg1—Br2ⁱ	110.13 (6)	C4—C5—H5A	120.2
C1—N1—C5	123.1 (8)	C1—C6—H6A	109.5
C1—N1—H1A	118.5	C1—C6—H6B	109.5
C5—N1—H1A	118.5	H6A—C6—H6B	109.5
N1—C1—C2	116.9 (8)	C1—C6—H6C	109.5
N1—C1—C6	117.3 (8)	H6A—C6—H6C	109.5
C2—C1—C6	125.8 (8)	H6B—C6—H6C	109.5
C3—C2—C1	122.0 (8)	C3—C7—H7A	109.5
C3—C2—H2A	119.0	C3—C7—H7B	109.5
C1—C2—H2A	119.0	H7A—C7—H7B	109.5
C2—C3—C4	118.0 (8)	C3—C7—H7C	109.5
C2—C3—C7	121.2 (8)	H7A—C7—H7C	109.5
C4—C3—C7	120.8 (9)	H7B—C7—H7C	109.5

C5—N1—C1—C2	−0.5 (13)	C1—C2—C3—C7	176.6 (7)
C5—N1—C1—C6	179.1 (9)	C2—C3—C4—C5	0.6 (15)
N1—C1—C2—C3	1.3 (12)	C7—C3—C4—C5	−177.4 (9)
C6—C1—C2—C3	−178.3 (8)	C1—N1—C5—C4	−0.1 (15)
C1—C2—C3—C4	−1.4 (13)	C3—C4—C5—N1	0.1 (16)

Symmetry code: (i) −x+1, y, −z+3/2.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···Br2ⁱⁱ	0.86	2.45	3.286 (7)	163

Symmetry code: (ii) x, −y, z+1/2.

Experimental details

Crystal data
Chemical formula	(C₇H₁₀N)₂[HgBr₄]
M_r	736.51
Crystal system, space group	Monoclinic, C2/c
Temperature (K)	293
a, b, c (Å)	20.022 (5), 7.7985 (9), 17.651 (3)
β (°)	129.12 (3)
V (Å³)	2138.1 (11)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	14.67
Crystal size (mm)	0.44 × 0.40 × 0.18

Data collection
Diffractometer	Agilent Xcalibur Eos diffractometer
Absorption correction	Multi-scan (CrysAlis PRO; Agilent, 2011)
T_min, T_max	0.002, 0.072
No. of measured, independent and observed [I > 2σ(I)] reflections	5366, 2895, 1454
R_int	0.036
(sin θ/λ)_max (Å⁻¹)	0.686

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.050, 0.102, 1.01
No. of reflections	2895
No. of parameters	98
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	1.45, −1.54

Computer programs: CrysAlis PRO (Agilent, 2011), SHELXTL (Sheldrick, 2008).

Selected bond lengths (Å) top

Hg1—Br1

2.5767 (11)

Hg1—Br2

2.6160 (11)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···Br2ⁱ	0.86	2.45	3.286 (7)	163.3

Symmetry code: (i) x, −y, z+1/2.

Acknowledgements

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

Agilent (2011). CrysAlis PRO. Agilent Technologies, Yarnton, England. Google Scholar
Al-Far, R. & Ali, B. F. (2007). Acta Cryst. C63, m137–m139. Web of Science CSD CrossRef IUCr Journals Google Scholar
Ali, B. F. & Al-Far, R. (2007). Acta Cryst. C63, m451–m453. Web of Science CSD CrossRef IUCr Journals Google Scholar
Ali, B. F., Al-Far, R. H. & Haddad, S. F. (2008). Acta Cryst. E64, m751–m752. Web of Science CSD CrossRef IUCr Journals Google Scholar
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. CrossRef Web of Science Google Scholar
Desiraju, G. R. (1997). Chem. Commun. pp. 1475–1482. CrossRef Web of Science Google Scholar
Gowda, B. T., Foro, S., Terao, H. & Fuess, H. (2009). Acta Cryst. E65, m946. Web of Science CSD CrossRef IUCr Journals Google Scholar
Li, S.-J., Chen, A.-H., Zheng, Z.-Y., Liu, S.-W. & Liu, Q.-X. (2009). Acta Cryst. E65, m1652. Web of Science CSD CrossRef IUCr Journals Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar