catena-Poly[aqua­bis­(μ-3-chloro­benzo­ato-κ²O:O′)zinc]

In the polymeric title compound, [Zn(C₇H₄ClO₂)₂(H₂O)]_n, the Zn^II cation is located on a twofold rotation axis and is coordinated by carboxylate O atoms of four monodentate chloro­benzoate anions and by one water mol­ecule, located on a twofold rotation axis, in a distorted square-pyramidal geometry. In the anion, the carboxyl­ate group is twisted away from the attached benzene ring by 44.16 (11)°. The chloro­benzoate anion bridges Zn^II cations, forming polymeric chains running along the c-axis direction. O—H...O hydrogen bonds between coordinating water mol­ecules and carboxyl­ate groups link adjacent chains into layers parallel to the bc plane.

Key indicators

• Single-crystal X-ray study
• T = 294 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.026
• wR factor = 0.069
• Data-to-parameter ratio = 17.4

checkCIF/PLATON results

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Alert level G
PLAT004_ALERT_5_G Info: Polymeric Structure Found with Dimension .          1
PLAT005_ALERT_5_G No _iucr_refine_instructions_details  in the CIF          ? Do !
PLAT232_ALERT_2_G Hirshfeld Test Diff (M-X)  Zn1    --  O1      ..        6.2 su

   0 ALERT level A = Most likely a serious problem - resolve or explain
   0 ALERT level B = A potentially serious problem, consider carefully
   0 ALERT level C = Check. Ensure it is not caused by an omission or oversight
   3 ALERT level G = General information/check it is not something unexpected

   0 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
   0 ALERT type 3 Indicator that the structure quality may be low
   0 ALERT type 4 Improvement, methodology, query or suggestion
   2 ALERT type 5 Informative message, check

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S1. Comment

The structural functions and coordination relationships of the arylcarboxylate ion in transition metal complexes of benzoic acid derivatives change depending on the nature and position of the substituent groups on the benzene ring, the nature of the additional ligand molecule or solvent, and the medium of the synthesis (Nadzhafov et al., 1981; Shnulin et al., 1981). Transition metal complexes with biochemically active ligands frequently show interesting physical and/or chemical properties, as a result they may find applications in biological systems (Antolini et al., 1982). Some benzoic acid derivatives, such as 4-aminobenzoic acid, have been extensively reported in coordination chemistry, as bifunctional organic ligands, due to the varieties of their coordination modes (Chen & Chen, 2002; Amiraslanov et al., 1979; Hauptmann et al., 2000). The title compound was synthesized and its crystal structure is reported herein.

The asymmetric unit of the title compound, (I), contains one-half Zn^II cation, one chlorobenzoate (CB) anion and one-half water molecule (Fig. 1). In the crystal, two CB anions bridge adjacent Zn^II cations, forming a polymeric chain running along the c axis, while the water molecule coordinate in a monodentate manner to the Zn^II cation, completing the distorted square-pyramidal geometry (Fig. 2). As a result of the CB anions bridging of the adjacent Zn^II cations, an eight-membered ring is formed where the distances between the symmetry related atoms, Zn1···Zn1b [4.3798 (3) Å], O1···O1b [3.020 (2) Å], O2···O2b [4.337 (2) Å] and C1···C1b [3.975 (2) Å] [symmetry code: (b) - x, - y, 1 - z], may reflect its size.

The crystal structures of some benzoate containing polymeric complexes of Mn^II, Zn^II, Pb^II and Co^II ions, [Mn₂(C₈H₇O₂)₄(C₁₀H₁₄N₂O)₂(H₂O)]_n (Hökelek et al., 2010a), [Mn(C₇H₄FO₂)₂(H₂O)₂]_n (Necefoğlu et al., 2011), [Zn(C₈H₅O₃)₂(C₆H₆N₂O)]_n (Hökelek et al., 2009), [Pb(C₈H₇O₂)₂(C₆H₆N₂O)]_n (Hökelek et al., 2010b), {[Pb(C₉H₉O₂)₂(C₆H₆N₂O)].H₂O}_n (Hökelek et al., 2011), {[Pb(C₇H₅O₃)₂(C₆H₆N₂O)].H₂O}_n (Zaman et al., 2012) and [Co(C₇H₄IO₂)₂(H₂O)₂]_n (Aydın et al., 2012) have also been reported.

In the title compound, the four O atoms (O1, O1a, O2b and O2c) [symmetry codes: (a) - x, y, 1/2 - z, (b) - x, - y, 1 - z, (c) x, - y, - 1/2 + z] in the equatorial plane around the Zn^II cation form a distorted square-planar arrangement, while the distorted square-pyramidal geometry is completed by the water O atom (O3) in the axial position. The near equalities of the C1—O1 [1.260 (2) Å] and C1—O2 [1.258 (2) Å] bonds in the carboxylate group indicate delocalized bonding arrangement, rather than localized single and double bonds. The average Zn—O bond length is 2.0636 (12) Å (for benzoate oxygens) and 1.9664 (19) Å (for water oxygen) (Table 1) close to standard values (Allen et al., 1987). The Zn atom is displaced out of the mean-plane of the carboxylate group (O1/C1/O2) by 1.3998 (1) Å. Atoms Cl1, C1 and O1 are -0.0897 (7), -0.0181 (16) and -0.2341 (12) Å away from the mean-plane of the adjacent benzene ring, respectively. The dihedral angle between the planar carboxylate group (O1/C1/O2) and the adjacent benzene ring A (C2—C7) is 44.16 (11)°.

In the crystal, strong O—H···O hydrogen bonds (Table 2) link the water hydrogens to the carboxylate oxygens in the polymeric chains (Fig. 3).

Related literature

For structural functions and coordination relationships of the arylcarboxylate ion in transition metal complexes of benzoic acid derivatives, see: Nadzhafov et al. (1981); Shnulin et al. (1981). For applications of transition metal complexes with biochemical molecules in biological systems, see: Antolini et al. (1982). Some benzoic acid derivatives, such as 4-aminobenzoic acid, have been extensively reported in coordination chemistry, as bifunctional organic ligands, due to the varieties of their coordination modes, see: Chen & Chen (2002); Amiraslanov et al. (1979); Hauptmann et al. (2000). For related structures, see: Aydın et al. (2012); Hökelek et al. (2009, 2010a,b, 2011); Necefoğlu et al. (2011); Zaman et al. (2012). For bond-length data, see: Allen et al. (1987).

S2. Experimental

The title compound was prepared by the reaction of ZnSO₄.H₂O (0.89 g, 5 mmol) in H₂O (50 ml) with sodium 3-chlorobenzoate (1.79 g, 10 mmol) in H₂O (100 ml) at room temperature. The mixture was filtered and set aside to crystallize at ambient temperature for one week, giving colorless single crystals.

S3. Refinement

Atom H31 (for H₂O) was located in a difference Fourier map and was refined freely. The C-bound H-atoms were positioned geometrically with C—H = 0.93 Å for aromatic H-atoms, and constrained to ride on their parent atoms, with U_iso(H) = 1.2U_eq(C).

Computing details

Data collection: APEX2 (Bruker, 2012); cell refinement: SAINT (Bruker, 2012); data reduction: SAINT (Bruker, 2012); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012); software used to prepare material for publication: WinGX (Farrugia, 2012) and PLATON (Spek, 2009).

Figures

	Fig. 1. The asymmetric unit of the title molecule with the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.
	Fig. 2. Part of the polymeric chain of the title compound.
	Fig. 3. A view along the b axis of the packing of the title compound (a axis horizontal; c axis vertical). Hydrogen bonds are shown as dashed lines.

catena-Poly[aquabis(µ-3-chlorobenzoato-κ²O:O')zinc]

Crystal data

[Zn(C7H4ClO2)2(H2O)]	F(000) = 792
Mr = 394.51	Dx = 1.784 Mg m^−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yc	Cell parameters from 9983 reflections
a = 31.8553 (8) Å	θ = 2.6–28.3°
b = 6.1786 (2) Å	µ = 2.06 mm^−1
c = 7.5117 (3) Å	T = 294 K
β = 96.554 (2)°	Block, colorless
V = 1468.80 (8) Å^3	0.35 × 0.25 × 0.15 mm
Z = 4

Data collection

Bruker SMART BREEZE CCD diffractometer	1825 independent reflections
Radiation source: fine-focus sealed tube	1727 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.036
φ and ω scans	θmax = 28.3°, θmin = 1.3°
Absorption correction: multi-scan (SADABS; Bruker, 2012)	h = −41→42
Tmin = 0.545, Tmax = 0.735	k = −8→8
13582 measured reflections	l = −8→10

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)] = 0.026	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.069	H atoms treated by a mixture of independent and constrained refinement
S = 1.12	w = 1/[σ^2(Fo^2) + (0.0337P)^2 + 1.4314P] where P = (Fo^2 + 2Fc^2)/3
1825 reflections	(Δ/σ)max = 0.002
105 parameters	Δρmax = 0.43 e Å^−3
0 restraints	Δρmin = −0.35 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
Zn1	1.0000	0.18233 (4)	0.2500	0.02388 (10)
Cl1	0.781898 (15)	−0.05564 (11)	−0.15745 (9)	0.05827 (18)
O1	0.97446 (4)	0.20515 (18)	−0.03094 (16)	0.0286 (3)
O2	1.05402 (4)	0.0674 (2)	0.19485 (18)	0.0368 (3)
O3	1.0000	0.5006 (3)	0.2500	0.0497 (6)
H31	0.9935 (8)	0.573 (4)	0.325 (3)	0.045 (7)*
C1	0.94299 (5)	0.1000 (3)	−0.1019 (2)	0.0250 (3)
C2	0.89932 (5)	0.1772 (2)	−0.0796 (2)	0.0263 (3)
C3	0.86489 (5)	0.0444 (3)	−0.1307 (2)	0.0306 (3)
H3	0.8687	−0.0906	−0.1814	0.037*
C4	0.82482 (5)	0.1162 (3)	−0.1050 (3)	0.0357 (4)
C5	0.81842 (6)	0.3189 (3)	−0.0349 (3)	0.0409 (5)
H5	0.7913	0.3660	−0.0205	0.049*
C6	0.85288 (6)	0.4504 (3)	0.0133 (3)	0.0411 (4)
H6	0.8489	0.5872	0.0600	0.049*
C7	0.89340 (6)	0.3808 (3)	−0.0069 (3)	0.0346 (4)
H7	0.9165	0.4694	0.0277	0.042*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Zn1	0.02038 (13)	0.01944 (13)	0.03266 (17)	0.000	0.00670 (10)	0.000
Cl1	0.0262 (2)	0.0787 (4)	0.0707 (4)	−0.0071 (2)	0.0089 (2)	−0.0203 (3)
O1	0.0262 (5)	0.0295 (6)	0.0302 (6)	−0.0027 (4)	0.0034 (5)	0.0041 (4)
O2	0.0225 (5)	0.0460 (7)	0.0416 (7)	0.0066 (5)	0.0027 (5)	−0.0187 (6)
O3	0.0973 (18)	0.0189 (8)	0.0384 (12)	0.000	0.0312 (12)	0.000
C1	0.0237 (7)	0.0287 (7)	0.0231 (8)	0.0039 (6)	0.0049 (6)	0.0027 (6)
C2	0.0241 (7)	0.0296 (8)	0.0256 (8)	0.0060 (5)	0.0052 (6)	0.0013 (6)
C3	0.0256 (7)	0.0356 (8)	0.0310 (9)	0.0043 (6)	0.0056 (6)	−0.0034 (7)
C4	0.0249 (8)	0.0485 (10)	0.0340 (9)	0.0030 (7)	0.0046 (7)	−0.0012 (8)
C5	0.0302 (9)	0.0523 (12)	0.0418 (11)	0.0169 (8)	0.0105 (8)	0.0013 (8)
C6	0.0432 (10)	0.0355 (9)	0.0459 (11)	0.0151 (8)	0.0107 (8)	−0.0036 (8)
C7	0.0337 (8)	0.0311 (8)	0.0395 (10)	0.0049 (7)	0.0062 (7)	−0.0030 (7)

Geometric parameters (Å, º)

Zn1—O1	2.1779 (12)	C2—C3	1.388 (2)
Zn1—O1^i	2.1779 (12)	C2—C7	1.393 (2)
Zn1—O2	1.9493 (11)	C3—C4	1.386 (2)
Zn1—O2^i	1.9493 (11)	C3—H3	0.9300
Zn1—O3	1.9664 (19)	C5—C4	1.383 (3)
Cl1—C4	1.740 (2)	C5—C6	1.380 (3)
O1—C1	1.260 (2)	C5—H5	0.9300
O2—C1^ii	1.258 (2)	C6—H6	0.9300
O3—H31	0.77 (2)	C7—C6	1.385 (2)
C1—O2^ii	1.258 (2)	C7—H7	0.9300
C2—C1	1.498 (2)
O1—Zn1—O1^i	172.58 (6)	C3—C2—C7	120.29 (15)
O2—Zn1—O1	93.38 (5)	C7—C2—C1	120.01 (15)
O2^i—Zn1—O1	89.33 (5)	C2—C3—H3	120.5
O2—Zn1—O1^i	89.33 (5)	C4—C3—C2	118.90 (16)
O2^i—Zn1—O1^i	93.38 (5)	C4—C3—H3	120.5
O2^i—Zn1—O2	137.26 (8)	C3—C4—Cl1	119.05 (16)
O2—Zn1—O3	111.37 (4)	C5—C4—Cl1	119.50 (14)
O2^i—Zn1—O3	111.37 (4)	C5—C4—C3	121.43 (18)
O3—Zn1—O1	86.29 (3)	C4—C5—H5	120.5
O3—Zn1—O1^i	86.29 (3)	C6—C5—C4	119.05 (16)
C1—O1—Zn1	124.58 (10)	C6—C5—H5	120.5
C1^ii—O2—Zn1	122.84 (11)	C5—C6—C7	120.76 (17)
Zn1—O3—H31	125.7 (19)	C5—C6—H6	119.6
O1—C1—C2	119.52 (14)	C7—C6—H6	119.6
O2^ii—C1—O1	123.47 (14)	C2—C7—H7	120.2
O2^ii—C1—C2	117.00 (14)	C6—C7—C2	119.54 (18)
C3—C2—C1	119.70 (14)	C6—C7—H7	120.2
O2—Zn1—O1—C1	116.58 (13)	C7—C2—C1—O2^ii	−168.37 (16)
O2^i—Zn1—O1—C1	−20.74 (13)	C1—C2—C3—C4	178.42 (16)
O3—Zn1—O1—C1	−132.21 (12)	C7—C2—C3—C4	−1.2 (3)
O1—Zn1—O2—C1^ii	−55.67 (14)	C1—C2—C7—C6	−179.91 (17)
O1^i—Zn1—O2—C1^ii	131.24 (14)	C3—C2—C7—C6	−0.3 (3)
O2^i—Zn1—O2—C1^ii	36.99 (13)	C2—C3—C4—Cl1	−176.52 (14)
O3—Zn1—O2—C1^ii	−143.01 (13)	C2—C3—C4—C5	2.0 (3)
Zn1—O1—C1—O2^ii	−100.74 (17)	C6—C5—C4—Cl1	177.28 (16)
Zn1—O1—C1—C2	80.48 (17)	C6—C5—C4—C3	−1.2 (3)
C3—C2—C1—O1	−169.14 (15)	C4—C5—C6—C7	−0.3 (3)
C3—C2—C1—O2^ii	12.0 (2)	C2—C7—C6—C5	1.1 (3)
C7—C2—C1—O1	10.5 (2)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O3—H31···O1^iii	0.77 (2)	1.89 (2)	2.6421 (17)	168 (2)

Symmetry code: (iii) x, −y+1, z+1/2.