Di-μ-chlorido-bis­{chlorido[2-(2-pyrid­yl)-1H-benzimidazole]cadmium(II)}

The title compound, [Cd₂Cl₄(C₁₂H₉N₃)₂], was prepared under hydro­thermal conditions. In the centrosymmetric dimeric molecule, two Cd^II atoms are bridged by two Cl atoms. One terminal Cl atom and two N atoms from a bidentate chelating 2-(2-pyrid­yl)benzimidazole ligand complete a distorted square-pyramidal geometry around each Cd^II atom. A three-dimensional network is constructed via inter­molecular N—H...Cl and weak C—H...Cl hydrogen bonds, as well as π–π inter­actions between adjacent ligands with a centroid-to-centroid distance of 3.49 (1) Å between the benzimidazolyl and pyridyl groups and a centroid-to-centroid distance of 3.54 (1) Å between the imidazolyl rings.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.004 Å
• R factor = 0.023
• wR factor = 0.062
• Data-to-parameter ratio = 17.0

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT029_ALERT_3_C _diffrn_measured_fraction_theta_full Low .......       0.97

Alert level G
PLAT199_ALERT_1_G Check the Reported _cell_measurement_temperature        293 K
PLAT200_ALERT_1_G Check the Reported _diffrn_ambient_temperature .        293 K
PLAT794_ALERT_5_G Check Predicted Bond Valency for Cd1         (2)       1.99

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   1 ALERT level C = Check and explain
   3 ALERT level G = General alerts; check

   2 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   0 ALERT type 2 Indicator that the structure model may be wrong or deficient
   1 ALERT type 3 Indicator that the structure quality may be low
   0 ALERT type 4 Improvement, methodology, query or suggestion
   1 ALERT type 5 Informative message, check

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S1. Comment

The 2-(2-pyridyl)benzimidazole ligand is often used to act as bidentate chelating ligand in metal complexes and those complexes can be mononuclear (Muller-Buschbaum & Quitmann, 2003), dinuclear (Dave & Czernuszewicz, 1994) or trinuclear (Tangoulis et al., 1996). The noncoordinating N—H group of the ligand acts as hydrogen bond donor for the formation of robust heteromeric hydrogen bonds, contributing to the crystal packing. Herein we report the synthesis and structure of the title compound with the 2-(2-pyridyl)benzimidazole ligand.

The title compound is a centrosymmetric dimeric complex. The Cd^II atom is five-coordinated in an N₂Cl₃ environment with a distorted square-pyramidal geometry (Fig. 1). Two Cd^II atoms are bridged by two Cl atoms, forming a coplanar Cd₂Cl₂ unit. The coordination geometry is completed by one terminal Cl atom and two N atoms from the chelating 2-(2-pyridyl)benzimidazole ligand (Table 1). Intermolecular N—H···Cl and C—H···Cl hydrogen bonds, as well as π–π interactions between the pyridyl and benzimidazole groups of two adjacent dinuclear units, with a centroid-to-centroid distance of 3.49 (1) Å, lead to a one-dimensional chain (Fig. 2). The individual chains are associated with each other through π–π interactions between the imidazole rings of the neighboring chains, with a centroid-to-centroid distance of 3.54 (1) Å, forming a two-dimensional layer structure. The layers are further connected into a three-dimensional network through weak C—H···Cl interactions [H2A···Cl2ⁱ = 2.92 Å, C2···Cl2ⁱ = 3.600 (2) Å, C2—H2A···Cl2ⁱ = 131°; symmetry code: (i) x, y - 1, z](Fig. 3).

Related literature

For related literature, see: Alcade et al. (1992); Dave & Czernuszewicz (1994); Muller-Buschbaum & Quitmann (2003); Tangoulis et al. (1996).

S2. Experimental

A solution of CdCl₂.2.5H₂O (0.14 g, 0.61 mmol), 2-(2-pyridyl)benzimidazole (0.08 g, 0.41 mmol) (Alcade et al., 1992) and H₂O (15 ml) was stirred under ambient condition, then sealed in a 25 ml Teflon-lined stainless steel vessel, heated at 383 K for 3 d and cooled to room temperature. The resulting product was collected by filtration, washed with distilled water and dried in air (yield 80%).

S3. Refinement

H atoms were positioned geometrically and refined as riding atoms, with C—H = 0.93 and N—H = 0.86Å and U_iso(H) = 1.2U_eq(C, N).

Computing details

Data collection: CrystalClear (Rigaku, 2002); cell refinement: CrystalClear (Rigaku, 2002); data reduction: CrystalClear (Rigaku, 2002); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Siemens, 1994); software used to prepare material for publication: SHELXL97 (Sheldrick, 1997).

Figures

	Fig. 1. Molecular structure of the title compound. Displacement ellipsoids are drawn at the 30% probability level. [Symmetry code: (i) 1 - x, 1 - y, 1 - z.]
	Fig. 2. A view of the one-dimensional chain in the title compound. H atoms have been omitted for clarity. Hydrogen bonds are shown as dashed lines.
	Fig. 3. The crystal packing of the title compound. Hydrogen bonds are shown as dashed lines.

Di-µ-chlorido-bis[chlorido[2-(2-pyridyl)-1H-benzimidazole]cadmium(II)]

Crystal data

[Cd2Cl4(C12H9N3)2]	Z = 1
Mr = 757.04	F(000) = 368
Triclinic, P1	Dx = 2.032 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 7.852 (2) Å	Cell parameters from 1784 reflections
b = 8.971 (2) Å	θ = 3.2–27.5°
c = 9.466 (3) Å	µ = 2.18 mm^−1
α = 103.224 (1)°	T = 293 K
β = 101.050 (2)°	Prism, colorless
γ = 100.665 (4)°	0.40 × 0.25 × 0.15 mm
V = 618.5 (3) Å^3

Data collection

Rigaku Mercury CCD diffractometer	2765 independent reflections
Radiation source: fine-focus sealed tube	2646 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.015
ω scan	θmax = 27.5°, θmin = 3.2°
Absorption correction: multi-scan (CrystalClear; Rigaku, 2002)	h = −10→7
Tmin = 0.525, Tmax = 0.718	k = −11→11
4683 measured reflections	l = −12→11

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)] = 0.023	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.062	H-atom parameters constrained
S = 1.05	w = 1/[σ^2(Fo^2) + (0.0411P)^2 + 0.1317P] where P = (Fo^2 + 2Fc^2)/3
2765 reflections	(Δ/σ)max = 0.002
163 parameters	Δρmax = 0.48 e Å^−3
0 restraints	Δρmin = −1.04 e Å^−3

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Cd1	0.702580 (19)	0.513530 (16)	0.653164 (14)	0.02650 (7)
Cl1	0.46761 (8)	0.67515 (7)	0.60517 (6)	0.03671 (13)
Cl2	0.99264 (7)	0.68125 (6)	0.66049 (6)	0.03132 (12)
C1	0.8247 (3)	0.1778 (3)	0.6348 (2)	0.0313 (4)
H1A	0.8154	0.1761	0.5350	0.038*
C2	0.8710 (3)	0.0522 (3)	0.6827 (3)	0.0343 (5)
H2A	0.8920	−0.0322	0.6161	0.041*
C3	0.8851 (3)	0.0548 (3)	0.8302 (3)	0.0338 (5)
H3A	0.9153	−0.0283	0.8646	0.041*
C4	0.8540 (3)	0.1826 (3)	0.9277 (2)	0.0305 (4)
H4A	0.8635	0.1870	1.0281	0.037*
C5	0.8084 (3)	0.3032 (2)	0.8712 (2)	0.0226 (4)
C6	0.7681 (3)	0.4433 (2)	0.9627 (2)	0.0219 (4)
C7	0.7286 (3)	0.6161 (2)	1.1522 (2)	0.0247 (4)
C8	0.7131 (3)	0.7043 (3)	1.2898 (2)	0.0321 (4)
H8A	0.7399	0.6726	1.3768	0.039*
C9	0.6561 (3)	0.8398 (3)	1.2894 (3)	0.0367 (5)
H9A	0.6423	0.9007	1.3783	0.044*
C10	0.6179 (3)	0.8898 (3)	1.1581 (3)	0.0358 (5)
H10A	0.5826	0.9839	1.1632	0.043*
C11	0.6318 (3)	0.8019 (3)	1.0226 (3)	0.0311 (4)
H11A	0.6053	0.8341	0.9360	0.037*
C12	0.6873 (3)	0.6625 (2)	1.0208 (2)	0.0239 (4)
N1	0.7931 (2)	0.3006 (2)	0.72678 (19)	0.0250 (3)
N2	0.7126 (2)	0.55058 (19)	0.90301 (18)	0.0237 (3)
N3	0.7801 (2)	0.4761 (2)	1.11117 (19)	0.0250 (3)
H3B	0.8134	0.4205	1.1694	0.030*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cd1	0.02836 (11)	0.03118 (10)	0.02066 (10)	0.00903 (7)	0.00083 (7)	0.01128 (7)
Cl1	0.0397 (3)	0.0401 (3)	0.0265 (3)	0.0207 (2)	−0.0043 (2)	0.0030 (2)
Cl2	0.0294 (3)	0.0367 (3)	0.0305 (3)	0.0082 (2)	0.0051 (2)	0.0162 (2)
C1	0.0372 (12)	0.0334 (10)	0.0232 (10)	0.0104 (9)	0.0057 (9)	0.0074 (8)
C2	0.0384 (12)	0.0284 (10)	0.0327 (11)	0.0120 (9)	0.0038 (9)	0.0028 (9)
C3	0.0371 (12)	0.0297 (10)	0.0356 (12)	0.0138 (9)	0.0019 (9)	0.0123 (9)
C4	0.0363 (11)	0.0319 (10)	0.0242 (10)	0.0113 (9)	0.0022 (8)	0.0115 (8)
C5	0.0192 (9)	0.0256 (9)	0.0223 (9)	0.0050 (7)	0.0014 (7)	0.0084 (7)
C6	0.0179 (8)	0.0261 (9)	0.0212 (9)	0.0049 (7)	0.0010 (7)	0.0089 (7)
C7	0.0201 (9)	0.0286 (9)	0.0231 (9)	0.0034 (7)	0.0022 (7)	0.0073 (8)
C8	0.0308 (11)	0.0391 (11)	0.0216 (10)	0.0040 (9)	0.0031 (8)	0.0051 (8)
C9	0.0337 (12)	0.0399 (12)	0.0292 (11)	0.0073 (10)	0.0063 (9)	−0.0022 (9)
C10	0.0332 (12)	0.0334 (11)	0.0384 (12)	0.0143 (9)	0.0048 (10)	0.0034 (9)
C11	0.0294 (11)	0.0333 (10)	0.0329 (11)	0.0124 (9)	0.0045 (9)	0.0121 (9)
C12	0.0204 (9)	0.0274 (9)	0.0221 (9)	0.0045 (7)	0.0028 (7)	0.0062 (7)
N1	0.0270 (9)	0.0257 (8)	0.0219 (8)	0.0059 (7)	0.0032 (7)	0.0081 (6)
N2	0.0241 (8)	0.0286 (8)	0.0203 (8)	0.0091 (7)	0.0038 (6)	0.0096 (6)
N3	0.0267 (9)	0.0279 (8)	0.0205 (8)	0.0068 (7)	0.0013 (6)	0.0101 (6)

Geometric parameters (Å, º)

Cd1—N2	2.2956 (17)	C6—N2	1.321 (2)
Cd1—N1	2.3581 (17)	C6—N3	1.350 (3)
Cd1—Cl2	2.4657 (8)	C7—N3	1.385 (3)
Cd1—Cl1	2.5852 (7)	C7—C12	1.399 (3)
Cd1—Cl1^i	2.5782 (7)	C7—C8	1.401 (3)
C1—N1	1.334 (3)	C8—C9	1.371 (3)
C1—C2	1.389 (3)	C8—H8A	0.9300
C1—H1A	0.9300	C9—C10	1.413 (4)
C2—C3	1.374 (3)	C9—H9A	0.9300
C2—H2A	0.9300	C10—C11	1.379 (3)
C3—C4	1.390 (3)	C10—H10A	0.9300
C3—H3A	0.9300	C11—C12	1.396 (3)
C4—C5	1.385 (3)	C11—H11A	0.9300
C4—Cl2^ii	3.690 (2)	C12—N2	1.392 (3)
C4—H4A	0.9300	N3—Cl2^ii	3.2708 (18)
C5—N1	1.344 (3)	N3—H3B	0.8600
C5—C6	1.477 (3)
N2—Cd1—N1	71.68 (6)	N3—C6—C5	125.53 (17)
N2—Cd1—Cl2	101.94 (5)	N3—C7—C12	105.75 (17)
N1—Cd1—Cl2	101.14 (5)	N3—C7—C8	132.14 (19)
N2—Cd1—Cl1^i	141.01 (5)	C12—C7—C8	122.10 (19)
N1—Cd1—Cl1^i	89.60 (5)	C9—C8—C7	116.4 (2)
Cl2—Cd1—Cl1^i	115.34 (2)	C9—C8—H8A	121.8
N2—Cd1—Cl1	95.34 (4)	C7—C8—H8A	121.8
N1—Cd1—Cl1	151.59 (5)	C8—C9—C10	122.1 (2)
Cl2—Cd1—Cl1	106.34 (3)	C8—C9—H9A	119.0
Cl1^i—Cd1—Cl1	85.21 (2)	C10—C9—H9A	119.0
Cd1^i—Cl1—Cd1	94.79 (2)	C11—C10—C9	121.3 (2)
N1—C1—C2	122.4 (2)	C11—C10—H10A	119.3
N1—C1—H1A	118.8	C9—C10—H10A	119.3
C2—C1—H1A	118.8	C10—C11—C12	117.3 (2)
C3—C2—C1	118.7 (2)	C10—C11—H11A	121.3
C3—C2—H2A	120.6	C12—C11—H11A	121.3
C1—C2—H2A	120.6	N2—C12—C11	130.41 (19)
C2—C3—C4	119.5 (2)	N2—C12—C7	108.79 (17)
C2—C3—H3A	120.2	C11—C12—C7	120.80 (19)
C4—C3—H3A	120.2	C1—N1—C5	118.60 (17)
C5—C4—C3	118.2 (2)	C1—N1—Cd1	124.66 (14)
C5—C4—Cl2^ii	110.35 (14)	C5—N1—Cd1	116.71 (13)
C3—C4—Cl2^ii	128.49 (14)	C6—N2—C12	105.63 (16)
C5—C4—H4A	120.9	C6—N2—Cd1	115.58 (13)
C3—C4—H4A	120.9	C12—N2—Cd1	138.63 (13)
N1—C5—C4	122.49 (19)	C6—N3—C7	107.08 (16)
N1—C5—C6	114.19 (16)	C6—N3—Cl2^ii	124.62 (12)
C4—C5—C6	123.30 (18)	C7—N3—Cl2^ii	125.61 (12)
N2—C6—N3	112.74 (17)	C6—N3—H3B	126.5
N2—C6—C5	121.72 (17)	C7—N3—H3B	126.5
N2—Cd1—Cl1—Cd1^i	−140.85 (5)	N2—Cd1—N1—C1	177.38 (19)
N1—Cd1—Cl1—Cd1^i	−80.23 (9)	Cl2—Cd1—N1—C1	−83.59 (18)
Cl2—Cd1—Cl1—Cd1^i	115.02 (2)	Cl1^i—Cd1—N1—C1	32.19 (17)
Cl1^i—Cd1—Cl1—Cd1^i	0.0	Cl1—Cd1—N1—C1	111.32 (17)
N1—C1—C2—C3	−0.1 (4)	N2—Cd1—N1—C5	−0.68 (14)
C1—C2—C3—C4	−0.4 (4)	Cl2—Cd1—N1—C5	98.35 (14)
C2—C3—C4—C5	0.4 (4)	Cl1^i—Cd1—N1—C5	−145.87 (14)
C2—C3—C4—Cl2^ii	−158.16 (17)	Cl1—Cd1—N1—C5	−66.74 (18)
C3—C4—C5—N1	0.1 (3)	N3—C6—N2—C12	0.4 (2)
Cl2^ii—C4—C5—N1	162.33 (15)	C5—C6—N2—C12	179.52 (18)
C3—C4—C5—C6	178.6 (2)	N3—C6—N2—Cd1	176.70 (13)
Cl2^ii—C4—C5—C6	−19.2 (2)	C5—C6—N2—Cd1	−4.2 (2)
N1—C5—C6—N2	3.5 (3)	C11—C12—N2—C6	179.2 (2)
C4—C5—C6—N2	−175.0 (2)	C7—C12—N2—C6	−0.5 (2)
N1—C5—C6—N3	−177.46 (19)	C11—C12—N2—Cd1	4.2 (4)
C4—C5—C6—N3	4.0 (3)	C7—C12—N2—Cd1	−175.48 (15)
N3—C7—C8—C9	−179.7 (2)	N1—Cd1—N2—C6	2.49 (14)
C12—C7—C8—C9	−0.4 (3)	Cl2—Cd1—N2—C6	−95.44 (14)
C7—C8—C9—C10	−1.0 (4)	Cl1^i—Cd1—N2—C6	67.61 (16)
C8—C9—C10—C11	1.7 (4)	Cl1—Cd1—N2—C6	156.59 (14)
C9—C10—C11—C12	−0.7 (4)	N1—Cd1—N2—C12	177.1 (2)
C10—C11—C12—N2	179.6 (2)	Cl2—Cd1—N2—C12	79.2 (2)
C10—C11—C12—C7	−0.7 (3)	Cl1^i—Cd1—N2—C12	−117.76 (19)
N3—C7—C12—N2	0.5 (2)	Cl1—Cd1—N2—C12	−28.8 (2)
C8—C7—C12—N2	−178.94 (19)	N2—C6—N3—C7	−0.1 (2)
N3—C7—C12—C11	−179.27 (19)	C5—C6—N3—C7	−179.20 (18)
C8—C7—C12—C11	1.3 (3)	N2—C6—N3—Cl2^ii	−162.33 (12)
C2—C1—N1—C5	0.6 (3)	C5—C6—N3—Cl2^ii	18.6 (3)
C2—C1—N1—Cd1	−177.40 (18)	C12—C7—N3—C6	−0.2 (2)
C4—C5—N1—C1	−0.6 (3)	C8—C7—N3—C6	179.1 (2)
C6—C5—N1—C1	−179.19 (19)	C12—C7—N3—Cl2^ii	161.78 (12)
C4—C5—N1—Cd1	177.57 (16)	C8—C7—N3—Cl2^ii	−18.9 (3)
C6—C5—N1—Cd1	−1.0 (2)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N3—H3B···Cl2^ii	0.86	2.45	3.2708 (18)	160
C4—H4A···Cl2^ii	0.93	2.83	3.690 (2)	155

Symmetry code: (ii) −x+2, −y+1, −z+2.