Crystal structure of catena-poly[1,3-di­benzyl­benzimidazolium [[chlorido­mercurate(II)]-di-μ-chlorido]]

The asymmetric unit of the polymeric title compound, {(C₂₁H₁₉N₂)[HgCl₃]}_n, comprises one-half of the cationic mol­ecule, the other half being generated by application of twofold rotation symmetry, one Hg and two Cl atoms. The Hg^II atom, lying on a twofold rotation axis, exhibits a distorted triangular coordination environment and is surrounded by three Cl atoms with Hg—Cl distances in the range 2.359 (2)–2.4754 (13) Å. Two additional longer distances [Hg⋯Cl = 3.104 (14) Å] lead to the formation of polymeric [HgCl_1/1Cl_4/2]⁻ chains extending along [001]. The crystal packing can be described by cationic layers alternating parallel to (-110) with the anionic chains located between the layers. The packing is consolidated by π–π stacking inter­actions between the benzene rings of the central benzimidazole entities, with centroid-to-centroid distances of 3.643 (3) Å.

1. Related literature

Benzimidazoles and their derivatives show anti-oxidant (Kuş et al., 2004), anti­fungal (Preston, 1974) and anthelminthic (Hazelton et al., 1995) properties and have applications in pharmacy and agriculture (Malek et al., 2006). They can also be used as ep­oxy resin curing agents, catalysts, metallic surface treatment agents (Li et al., 2003; Abboud et al., 2006) or as ionic liquids (Li et al., 2011; Chen et al., 2008). For the importance of transition metals ions in biological processes, see: Kaim & Schwederski (1994). For bond lengths of delocalized systems, see: Ennajih et al. (2009).

2. Experimental

2.1. Crystal data

• (C₂₁H₁₉N₂)[HgCl₃]

• M_r = 606.32

• Monoclinic, C 2/c

• a = 20.3669 (11) Å

• b = 14.8837 (7) Å

• c = 7.2154 (4) Å

• β = 104.372 (2)°

• V = 2118.79 (19) ų

• Z = 4

• Mo Kα radiation

• μ = 7.65 mm⁻¹

• T = 295 K

• 0.19 × 0.11 × 0.05 mm

2.2. Data collection

• Bruker APEXII CCD diffractometer

• Absorption correction: multi-scan (SADABS; Bruker, 2011) T_min = 0.646, T_max = 0.746

• 8306 measured reflections

• 2401 independent reflections

• 1571 reflections with I > 2σ(I)

• R_int = 0.042

2.3. Refinement

• R[F² > 2σ(F²)] = 0.038

• wR(F²) = 0.085

• S = 1.00

• 2401 reflections

• 124 parameters

• H-atom parameters constrained

• Δρ_max = 2.02 e Å⁻³

• Δρ_min = −0.41 e Å⁻³

Data collection: APEX2 (Bruker, 2011); cell refinement: SAINT (Bruker, 2011); data reduction: SAINT; program(s) used to solve structure: SIR2002 (Burla et al., 2005); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012) and DIAMOND (Brandenburg & Berndt, 2001); software used to prepare material for publication: WinGX (Farrugia, 2012).

Supporting information

Related literature

Benzimidazoles and their derivatives show anti-oxidant (Kuş et al., 2004), antifungal (Preston, 1974) and anthelminthic (Hazelton et al., 1995) properties and have applications in pharmacy and agriculture (Malek et al., 2006). They can also be used as epoxy resin curing agents, catalysts, metallic surface treatment agents (Li et al., 2003; Abboud et al., 2006) or as ionic liquids (Li et al., 2011; Chen et al., 2008). For the importance of transition metals ions in biological processes, see: Kaim & Schwederski (1994). For bond lengths of delocalized systems, see: Ennajih et al. (2009).

S1. Experimental

1,3-Dibenzylbenzimidazolium trichloridomercurate(II) was synthesized by reaction of 1 mmol of 1,3-dibenzylbenzimidazolium chloride with 1 mmol of mercury(II) chloride in methanol at room temperature. The solid obtained was recrystallized in methanol to yield yellow crystals of the title compound suitable for X-ray diffraction.

S2. Refinement

H atoms were localized from difference maps but were modelled in calculated positions and treated as riding on their parent atom with C—H = 0.93 Å (aromatic), C—H = 0.97 Å (methylene) with U_iso(H) = 1.2U_eq(C_aromatic or C_methylene).

Structure description

Benzimidazoles and their derivatives show anti-oxidant (Kuş et al., 2004), antifungal (Preston, 1974) and anthelminthic (Hazelton et al., 1995) properties and have applications in pharmacy and agriculture (Malek et al., 2006). They can also be used as epoxy resin curing agents, catalysts, metallic surface treatment agents (Li et al., 2003; Abboud et al., 2006) or as ionic liquids (Li et al., 2011; Chen et al., 2008). For the importance of transition metals ions in biological processes, see: Kaim & Schwederski (1994). For bond lengths of delocalized systems, see: Ennajih et al. (2009).

Computing details

Data collection: APEX2 (Bruker, 2011); cell refinement: SAINT (Bruker, 2011); data reduction: SAINT (Bruker, 2011); program(s) used to solve structure: SIR2002 (Burla et al., 2005); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012) and DIAMOND (Brandenburg & Berndt, 2001); software used to prepare material for publication: WinGX (Farrugia, 2012).

Figures

	Fig. 1. The molecular structures of the entities in the title compound. Displacement ellipsoids are drawn at the 50% probability level; H atoms are represented as small spheres of arbitrary radius. Non-labelled atoms are generated by symmetry code 2 - x, y, 3/2 - z for the cation and by symmetry code 2 - x, y, 1/2 - z for the anion.
	Fig. 2. The polymeric anionic [HgCl1/1Cl4/2]^- chain defined by long Hg—Cl distances (in dashed lines).
	Fig. 3. The crystal packing of the title compound viewed down [010] showing alternating layers of cations and anions.
	Fig. 4. The crystal packing of the title compound viewed down [001] (chain direction).

catena-Poly[1,3-dibenzylbenzimidazolium [[chloridomercurate(II)]-di-µ-chlorido]]

Crystal data

(C21H19N2)[HgCl3]	F(000) = 1160
Mr = 606.32	Dx = 1.901 Mg m^−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yc	Cell parameters from 2352 reflections
a = 20.3669 (11) Å	θ = 2.7–22.8°
b = 14.8837 (7) Å	µ = 7.65 mm^−1
c = 7.2154 (4) Å	T = 295 K
β = 104.372 (2)°	Prism, yellow
V = 2118.79 (19) Å^3	0.19 × 0.11 × 0.05 mm
Z = 4

Data collection

Bruker APEXII CCD diffractometer	2401 independent reflections
Radiation source: Enraf Nonius FR590	1571 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.042
CCD rotation images, thick slices scans	θmax = 27.5°, θmin = 2.7°
Absorption correction: multi-scan (SADABS; Bruker, 2011)	h = −26→26
Tmin = 0.646, Tmax = 0.746	k = −18→13
8306 measured reflections	l = −9→9

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.038	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.085	H-atom parameters constrained
S = 1.00	w = 1/[σ^2(Fo^2) + (0.0419P)^2] where P = (Fo^2 + 2Fc^2)/3
2401 reflections	(Δ/σ)max = 0.002
124 parameters	Δρmax = 2.02 e Å^−3
0 restraints	Δρmin = −0.41 e Å^−3

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq
Hg1	1	0.050020 (19)	0.25	0.05935 (16)
Cl2	0.91850 (7)	−0.05454 (8)	0.33958 (18)	0.0473 (3)
Cl1	1	0.20850 (14)	0.25	0.0888 (9)
N1	0.9472 (2)	0.3140 (3)	0.6672 (6)	0.0415 (10)
C4	1	0.2622 (5)	0.75	0.0484 (19)
H4	1	0.1998	0.75	0.058*
C6	0.8265 (3)	0.3186 (3)	0.6596 (8)	0.0446 (13)
C3	0.9676 (2)	0.4034 (3)	0.6988 (6)	0.0348 (11)
C1	0.9672 (3)	0.5616 (3)	0.6966 (8)	0.0463 (14)
H1	0.9458	0.6165	0.6613	0.056*
C2	0.9314 (3)	0.4838 (4)	0.6393 (7)	0.0418 (12)
H2	0.8868	0.4841	0.5667	0.05*
C5	0.8795 (3)	0.2814 (4)	0.5694 (8)	0.0524 (14)
H5A	0.8789	0.2163	0.5749	0.063*
H5B	0.8694	0.299	0.4359	0.063*
C7	0.8324 (3)	0.3053 (4)	0.8527 (9)	0.0569 (15)
H7	0.8683	0.2721	0.9258	0.068*
C11	0.7722 (3)	0.3668 (4)	0.5561 (9)	0.0574 (15)
H11	0.768	0.3764	0.4263	0.069*
C8	0.7847 (4)	0.3418 (5)	0.9352 (9)	0.0751 (19)
H8	0.7893	0.3342	1.0658	0.09*
C9	0.7303 (3)	0.3891 (5)	0.8308 (12)	0.075 (2)
H9	0.6982	0.4127	0.8894	0.091*
C10	0.7238 (3)	0.4013 (4)	0.6396 (12)	0.0695 (18)
H10	0.6869	0.4327	0.5663	0.083*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Hg1	0.0830 (3)	0.02880 (19)	0.0678 (2)	0	0.02171 (18)	0
Cl2	0.0457 (8)	0.0495 (8)	0.0472 (7)	−0.0016 (6)	0.0120 (6)	0.0026 (6)
Cl1	0.146 (3)	0.0298 (12)	0.0719 (15)	0	−0.0079 (15)	0
N1	0.037 (3)	0.031 (2)	0.053 (3)	−0.0031 (19)	0.006 (2)	−0.0073 (19)
C4	0.043 (5)	0.033 (4)	0.068 (5)	0	0.010 (4)	0
C6	0.031 (3)	0.032 (3)	0.064 (4)	−0.005 (2)	−0.002 (3)	−0.008 (2)
C3	0.037 (3)	0.033 (3)	0.036 (3)	0.003 (2)	0.012 (2)	−0.003 (2)
C1	0.055 (3)	0.029 (3)	0.056 (3)	0.011 (2)	0.014 (3)	0.006 (2)
C2	0.039 (3)	0.042 (3)	0.042 (3)	0.003 (2)	0.006 (2)	−0.003 (2)
C5	0.044 (3)	0.048 (3)	0.059 (3)	−0.005 (3)	0.001 (3)	−0.018 (3)
C7	0.042 (4)	0.060 (4)	0.063 (4)	−0.004 (3)	0.001 (3)	0.003 (3)
C11	0.048 (4)	0.056 (4)	0.062 (4)	−0.007 (3)	0.001 (3)	0.002 (3)
C8	0.068 (5)	0.098 (6)	0.062 (4)	−0.013 (4)	0.020 (4)	−0.012 (4)
C9	0.052 (4)	0.075 (5)	0.106 (6)	−0.007 (4)	0.033 (4)	−0.027 (4)
C10	0.043 (4)	0.053 (4)	0.109 (6)	0.000 (3)	0.012 (4)	−0.001 (4)

Geometric parameters (Å, º)

Hg1—Cl1	2.359 (2)	C1—C2	1.376 (7)
Hg1—Cl2^i	2.4754 (13)	C1—H1	0.93
Hg1—Cl2	2.4754 (13)	C2—H2	0.93
N1—C4	1.336 (6)	C5—H5A	0.97
N1—C3	1.397 (6)	C5—H5B	0.97
N1—C5	1.466 (6)	C7—C8	1.372 (9)
C4—N1^ii	1.336 (6)	C7—H7	0.93
C4—H4	0.93	C11—C10	1.375 (9)
C6—C11	1.374 (7)	C11—H11	0.93
C6—C7	1.383 (8)	C8—C9	1.370 (10)
C6—C5	1.499 (7)	C8—H8	0.93
C3—C3^ii	1.344 (9)	C9—C10	1.365 (10)
C3—C2	1.414 (7)	C9—H9	0.93
C1—C1^ii	1.367 (11)	C10—H10	0.93
Cl1—Hg1—Cl2^i	128.95 (3)	N1—C5—C6	111.2 (4)
Cl1—Hg1—Cl2	128.95 (3)	N1—C5—H5A	109.4
Cl2^i—Hg1—Cl2	102.09 (6)	C6—C5—H5A	109.4
C4—N1—C3	107.6 (4)	N1—C5—H5B	109.4
C4—N1—C5	125.5 (4)	C6—C5—H5B	109.4
C3—N1—C5	126.8 (4)	H5A—C5—H5B	108
N1^ii—C4—N1	109.7 (6)	C8—C7—C6	119.1 (6)
N1^ii—C4—H4	125.2	C8—C7—H7	120.4
N1—C4—H4	125.2	C6—C7—H7	120.4
C11—C6—C7	118.7 (6)	C6—C11—C10	121.7 (6)
C11—C6—C5	121.8 (5)	C6—C11—H11	119.2
C7—C6—C5	119.5 (5)	C10—C11—H11	119.2
C3^ii—C3—N1	107.5 (3)	C9—C8—C7	121.9 (6)
C3^ii—C3—C2	122.2 (3)	C9—C8—H8	119
N1—C3—C2	130.2 (4)	C7—C8—H8	119
C1^ii—C1—C2	122.7 (3)	C10—C9—C8	119.1 (6)
C1^ii—C1—H1	118.7	C10—C9—H9	120.4
C2—C1—H1	118.7	C8—C9—H9	120.4
C1—C2—C3	115.1 (5)	C9—C10—C11	119.5 (6)
C1—C2—H2	122.5	C9—C10—H10	120.2
C3—C2—H2	122.5	C11—C10—H10	120.2
C3—N1—C4—N1^ii	0.1 (2)	C11—C6—C5—N1	123.0 (5)
C5—N1—C4—N1^ii	−177.2 (5)	C7—C6—C5—N1	−56.1 (7)
C4—N1—C3—C3^ii	−0.2 (6)	C11—C6—C7—C8	−1.0 (8)
C5—N1—C3—C3^ii	177.1 (5)	C5—C6—C7—C8	178.1 (5)
C4—N1—C3—C2	179.0 (4)	C7—C6—C11—C10	−0.5 (8)
C5—N1—C3—C2	−3.7 (8)	C5—C6—C11—C10	−179.6 (5)
C1^ii—C1—C2—C3	0.0 (9)	C6—C7—C8—C9	1.7 (10)
C3^ii—C3—C2—C1	−1.1 (8)	C7—C8—C9—C10	−0.8 (10)
N1—C3—C2—C1	179.8 (5)	C8—C9—C10—C11	−0.7 (10)
C4—N1—C5—C6	121.4 (5)	C6—C11—C10—C9	1.3 (9)
C3—N1—C5—C6	−55.4 (7)

Symmetry codes: (i) −x+2, y, −z+1/2; (ii) −x+2, y, −z+3/2.