catena-Poly[[dichloridozinc(II)]-μ-1-carboxyl­atomethyl-3-methyl­imidazolium-κ²O:O′]

The crystal structure of the title compound, [ZnCl₂(C₆H₈N₂O₂)]_n, consists of a zigzag chain in which adjacent ZnCl₂ groups are bridged by 1-carboxyl­atomethyl-3-methyl­imidazolium through its two O atoms. The environment around the Zn atom can be described as a cis-ZnO₂Cl₂ tetrahedron. The formation of the chain is strengthened by π–π stacking inter­actions between adjacent imidazole ring planes (π–π distance = 3.618 Å).

Key indicators

• Single-crystal X-ray study
• T = 296 K
• Mean [sigma](C-C) = 0.006 Å
• R factor = 0.033
• wR factor = 0.068
• Data-to-parameter ratio = 16.9

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT029_ALERT_3_C _diffrn_measured_fraction_theta_full Low .......       0.97
PLAT066_ALERT_1_C Predicted and Reported Transmissions Identical .          ?
PLAT380_ALERT_4_C Check Incorrectly? Oriented X(sp2)-Methyl Moiety         C1

Alert level G
REFLT03_ALERT_4_G Please check that the estimate of the number of Friedel pairs is
            correct. If it is not, please give the correct count in the
            _publ_section_exptl_refinement section of the submitted CIF.
           From the CIF: _diffrn_reflns_theta_max           27.70
           From the CIF: _reflns_number_total               1994
           Count of symmetry unique reflns         1200
           Completeness (_total/calc)            166.17%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured       794
           Fraction of Friedel pairs measured     0.662
           Are heavy atom types Z>Si present        yes
PLAT033_ALERT_2_G Flack Parameter Value Deviates 2 * su from zero.       0.05
PLAT794_ALERT_5_G Check Predicted Bond Valency for Zn1         (2)       2.02

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

   1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   1 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
   2 ALERT type 4 Improvement, methodology, query or suggestion
   1 ALERT type 5 Informative message, check

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S1. Comment

It is known that the research of coordination polymers receives great interest nowadays, because they may afford new materials with useful properties, such as catalytic activity, microporosity and so on (Shi et al., 2004). Recently, we have synthesized and reported cadmium polymer with 1-methyl-3-carboxymethylimidazole (Shi et al., 2007). As an extension of our work in this field, we synthesized the title compound and solved its crystal structure (I).

The asymmetric unit of (I) contains one Zn atom, one 1-methyl-3-carboxymethylimidazole molecule, and two chlorine atoms (Fig. 1). The structure of (I) is a one-dimensional coordination chain in which the adjacent (ZnCl₂) groups are bridged by 1-methyl-3-carboxymethylimidazole through its two O atoms with the distance of 4.8362 (4)Å (a-translation) between two adjacent Zn atoms. There exists π-π interaction between the adjacent imidazole-ring planes (π-π distance = 3.618 Å), which strengthens the formation of the chain.

Related literature

For related literature, see: Shi et al. (2004, 2007).

For related literature, see: Sheldrick (1997).

S2. Experimental

A mixture of ZnCl₂ (1 mmol), ion liquid 1-methyl-3-carboxymethylimidazole hydroxide (1 mmol) and water (20 ml) was sealed in a 25 ml Teflon-lined stainless steel reactor and heated at 393 K for 48 h. A colourless solution was obtained after cooling the reaction to room temperature, colourless single crystals were obtained after three weeks.

S3. Refinement

The H atoms bonded to C atoms were positioned geometrically (aromatic C–H = 0.93Å and aliphatic C–H = 0.97 Å, U_iso(H) = 1.2U_eq(C)). In the X-ray diffraction experiment 794 Friedel pairs were measured.

Computing details

Data collection: SMART (Bruker, 2004); cell refinement: SMART (Bruker, 2004) and SAINT (Bruker, 2004); data reduction: XPREP (Bruker 2002); program(s) used to solve structure: SHELXTL (Bruker 2002); program(s) used to refine structure: SHELXTL (Bruker 2002); molecular graphics: SHELXTL (Bruker 2002); software used to prepare material for publication: SHELXTL (Bruker 2002).

Figures

	Fig. 1. A view of the molecule of (I) with the atom-labelling scheme. Displacement ellipsoids are drawn at the 50% probability. H atoms are presented as spheres with arbitrary radius. Symmetry code: (i) -1 + x, y, z;
	Fig. 2. The one-dimensional chain in crystal structure of (I).

catena-Poly[[dichloridozinc(II)]-µ-1-carboxylatomethyl-3-methylimidazolium-\ κ²O:O']

Crystal data

[ZnCl2(C6H8N2O2)]	F(000) = 276
Mr = 276.43	Dx = 1.814 Mg m^−3
Monoclinic, Pc	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P -2yc	Cell parameters from 1309 reflections
a = 4.8362 (4) Å	θ = 2.8–27.7°
b = 10.5820 (9) Å	µ = 2.92 mm^−1
c = 10.1164 (7) Å	T = 296 K
β = 102.183 (5)°	Prism, colourless
V = 506.06 (7) Å^3	0.35 × 0.11 × 0.05 mm
Z = 2

Data collection

Bruker P4 diffractometer	1994 independent reflections
Radiation source: fine-focus sealed tube	1691 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.020
ω scans	θmax = 27.7°, θmin = 2.8°
Absorption correction: empirical (using intensity measurements) (SADABS; Sheldrick, 1996)	h = −6→6
Tmin = 0.687, Tmax = 0.864	k = −13→13
3003 measured reflections	l = −12→12

Refinement

Refinement on F^2	Secondary atom site location: Difmap
Least-squares matrix: Full	Hydrogen site location: Geom
R[F^2 > 2σ(F^2)] = 0.033	H-atom parameters constrained
wR(F^2) = 0.068	w = 1/[σ^2(Fo^2) + (0.025P)^2], where P = (Fo^2 + 2Fc^2)/3
S = 1.01	(Δ/σ)max < 0.001
1994 reflections	Δρmax = 0.45 e Å^−3
118 parameters	Δρmin = −0.59 e Å^−3
0 restraints	Absolute structure: Flack (1983)
Primary atom site location: Direct	Absolute structure parameter: 0.055 (15)

Special details

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 > 2σ(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
Zn1	0.03320 (7)	0.76339 (4)	−0.06177 (5)	0.03457 (14)
Cl1	0.0646 (3)	0.96102 (10)	−0.13316 (14)	0.0511 (3)
Cl2	−0.0059 (2)	0.61405 (10)	−0.21919 (13)	0.0468 (3)
C1	0.3986 (10)	0.8408 (5)	0.6340 (4)	0.0485 (12)
H1A	0.4590	0.9268	0.6288	0.073*
H1B	0.4907	0.8052	0.7192	0.073*
H1C	0.1974	0.8386	0.6263	0.073*
C2	0.4180 (10)	0.6411 (4)	0.5010 (5)	0.0415 (11)
H2A	0.3230	0.5893	0.5510	0.050*
C3	0.5240 (9)	0.6061 (4)	0.3952 (4)	0.0395 (11)
H3A	0.5146	0.5260	0.3566	0.047*
C4	0.6128 (8)	0.8075 (4)	0.4347 (5)	0.0339 (10)
H4A	0.6756	0.8899	0.4289	0.041*
C5	0.7844 (8)	0.7217 (4)	0.2374 (4)	0.0352 (9)
H5A	0.8972	0.6465	0.2335	0.042*
H5B	0.9111	0.7938	0.2495	0.042*
C6	0.5754 (8)	0.7356 (4)	0.1059 (4)	0.0317 (9)
N1	0.4738 (8)	0.7668 (3)	0.5229 (4)	0.0355 (9)
N2	0.6513 (7)	0.7124 (4)	0.3538 (4)	0.0305 (8)
O1	0.6675 (6)	0.7498 (3)	0.0018 (3)	0.0518 (9)
O2	0.3161 (5)	0.7312 (3)	0.1078 (3)	0.0481 (9)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Zn1	0.02622 (18)	0.0510 (3)	0.0276 (2)	0.0024 (3)	0.00809 (14)	0.0035 (3)
Cl1	0.0555 (6)	0.0378 (6)	0.0633 (8)	0.0024 (5)	0.0199 (6)	−0.0084 (6)
Cl2	0.0494 (6)	0.0366 (6)	0.0562 (7)	0.0000 (5)	0.0149 (5)	−0.0038 (5)
C1	0.060 (3)	0.056 (3)	0.032 (3)	0.006 (2)	0.014 (2)	−0.005 (2)
C2	0.045 (2)	0.045 (3)	0.038 (3)	−0.006 (2)	0.014 (2)	0.005 (2)
C3	0.046 (2)	0.035 (3)	0.039 (3)	−0.002 (2)	0.012 (2)	−0.0028 (19)
C4	0.031 (2)	0.041 (2)	0.030 (2)	−0.0055 (16)	0.007 (2)	0.002 (2)
C5	0.0240 (17)	0.051 (3)	0.032 (2)	0.0018 (18)	0.0103 (16)	0.003 (2)
C6	0.0272 (18)	0.041 (2)	0.029 (2)	0.0004 (17)	0.0096 (16)	0.0044 (18)
N1	0.035 (2)	0.045 (2)	0.027 (2)	0.0004 (16)	0.0067 (17)	0.0027 (17)
N2	0.0275 (17)	0.042 (2)	0.024 (2)	−0.0023 (16)	0.0103 (15)	0.0028 (17)
O1	0.0256 (13)	0.105 (3)	0.0262 (18)	0.0044 (15)	0.0089 (12)	0.0114 (16)
O2	0.0210 (13)	0.091 (3)	0.0336 (17)	0.0011 (14)	0.0078 (12)	0.0107 (17)

Geometric parameters (Å, º)

Zn1—O2	1.985 (3)	C3—H3A	0.9300
Zn1—O1^i	2.011 (3)	C4—N1	1.298 (6)
Zn1—Cl2	2.2231 (13)	C4—N2	1.335 (6)
Zn1—Cl1	2.2281 (12)	C4—H4A	0.9300
C1—N1	1.477 (6)	C5—N2	1.460 (6)
C1—H1A	0.9600	C5—C6	1.499 (6)
C1—H1B	0.9600	C5—H5A	0.9700
C1—H1C	0.9600	C5—H5B	0.9700
C2—C3	1.334 (6)	C6—O1	1.235 (5)
C2—N1	1.366 (5)	C6—O2	1.259 (5)
C2—H2A	0.9300	O1—Zn1^ii	2.011 (3)
C3—N2	1.388 (6)
O2—Zn1—O1^i	101.74 (11)	N1—C4—H4A	125.3
O2—Zn1—Cl2	115.85 (11)	N2—C4—H4A	125.3
O1^i—Zn1—Cl2	103.34 (11)	N2—C5—C6	113.2 (3)
O2—Zn1—Cl1	111.06 (11)	N2—C5—H5A	108.9
O1^i—Zn1—Cl1	107.20 (11)	C6—C5—H5A	108.9
Cl2—Zn1—Cl1	115.87 (5)	N2—C5—H5B	108.9
N1—C1—H1A	109.5	C6—C5—H5B	108.9
N1—C1—H1B	109.5	H5A—C5—H5B	107.8
H1A—C1—H1B	109.5	O1—C6—O2	123.9 (4)
N1—C1—H1C	109.5	O1—C6—C5	118.1 (3)
H1A—C1—H1C	109.5	O2—C6—C5	118.0 (3)
H1B—C1—H1C	109.5	C4—N1—C2	108.9 (4)
C3—C2—N1	107.7 (4)	C4—N1—C1	126.4 (4)
C3—C2—H2A	126.1	C2—N1—C1	124.6 (4)
N1—C2—H2A	126.1	C4—N2—C3	107.3 (4)
C2—C3—N2	106.7 (4)	C4—N2—C5	125.9 (4)
C2—C3—H3A	126.7	C3—N2—C5	126.6 (4)
N2—C3—H3A	126.7	C6—O1—Zn1^ii	141.3 (3)
N1—C4—N2	109.4 (4)	C6—O2—Zn1	119.1 (3)
N1—C2—C3—N2	1.1 (5)	C2—C3—N2—C5	−176.8 (4)
N2—C5—C6—O1	176.9 (4)	C6—C5—N2—C4	−96.5 (5)
N2—C5—C6—O2	−3.7 (5)	C6—C5—N2—C3	78.6 (5)
N2—C4—N1—C2	0.2 (5)	O2—C6—O1—Zn1^ii	−180.0 (4)
N2—C4—N1—C1	177.2 (4)	C5—C6—O1—Zn1^ii	−0.6 (7)
C3—C2—N1—C4	−0.8 (5)	O1—C6—O2—Zn1	−5.6 (6)
C3—C2—N1—C1	−178.0 (4)	C5—C6—O2—Zn1	175.0 (3)
N1—C4—N2—C3	0.5 (5)	O1^i—Zn1—O2—C6	−178.3 (3)
N1—C4—N2—C5	176.4 (4)	Cl2—Zn1—O2—C6	70.5 (3)
C2—C3—N2—C4	−1.0 (5)	Cl1—Zn1—O2—C6	−64.5 (3)

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