catena-Poly[[diaqua­zinc(II)]-μ-4,4′-sulfonyl­dibenzoato-κ²O:O′]

The title compound, [Zn(C₁₄H₈O₆S)(H₂O)₂]_n, is the first reported metal complex of the 4,4′-sulfonyl­dibenzoate anion. The structure comprises zigzag chains of alternating [Zn(H₂O)₂]²⁺ and sulfonyl­dibenzoate units, the central Zn and S atoms of which lie on crystallographic twofold axes. The Zn^II centre occupies a strongly distorted tetra­hedral environment [O—Zn—O = 83.30 (7)–136.19 (8)°], coordinated by the two water O atoms [Zn—O = 1.986 (2) Å] and one O atom from each of two carboxyl­ate groups [Zn—O = 1.9942 (19) Å], with much longer contacts to the other O atoms of these carboxyl­ates [Zn—O = 2.528 (2) Å]. Hydrogen bonds between carboxyl­ate O atoms and coordinated water mol­ecules in adjacent chains lead to the formation of a three-dimensional network structure.

S1. Comment

In recent years, much attention has been focused on the design and synthesis of supramolecular complexes because of their novel structural architectures and potential applications in catalysis, magnetism, ion exchange and non-linear optics (Atwood et al., 1996; Barton et al., 1999; Lo et al., 2000). The basic strategy for the synthesis of such compounds involves connecting metal-containing building blocks with various multidentate ligands. As an important family of these multidentate ligands, organic aromatic polycarboxylate ligands such as 1,2-benzenedicarboxylate, 1,3,5-benzenetricarboxylate, 3,3',4,4'-benzophenonetetracarboxylate and 1,2,4,5-benzenetetracarboxylate have been extensively employed in the preparation of such metal–organic complexes. These products exhibit both high dimensionality in their structures and interesting properties (Chui et al., 1999; Li et al., 1999; Zhang et al., 2004). Similarly, the 4,4'-sulfonyldibenzoate anion (hereinafter DSDC) can act as a versatile ligand for the construction of novel metal–organic hybrid compounds, due to the presence of two carboxylate functions and its structural flexibility. However, to the best of our knowledge, no metal complexes with DSDC have been reported to date. Therefore, with the aim of exploring the coordination chemistry of DSDC, the title complex, (I), was obtained from the hydrothermal reaction of 4,4'-sulfonylbis(methyl benzoate) with zinc acetate and sodium hydroxide.

As shown in Fig. 1, the Zn centres in (I) are four-coordinate in a highly distorted tetrahedral environment involving two O-donors of two DSDC ligands and two coordinated water molecules. The Zn^II centre occupies a strongly distorted tetrahedral environment [O—Zn—O = 83.30 (7)–136.19 (8)°], coordinated by the two water O atoms [Zn—O = 1.986 (2) Å] and one O atom from each of two carboxylate groups [Zn—O = 1.9942 (19) Å], with much longer contacts to the other O atoms of these carboxylates [Zn—O = 2.528 (2) Å]. The bonded distances are in agreement with values reported in other zinc carboxylate complexes (Monge et al., 2005; Wang et al., 2006; He et al., 2006). The DSDC group acts as a bidentate ligand in this structure, with both carboxylate groups each coordinating in an essentially monodentate manner to the Zn^II centres.

The structure of (I) comprises strongly zigzag chains of alternating [Zn(H₂O)₂]²⁺ and sulfonyldibenzoate units, with their respective Zn and S atoms lying on crystallographic twofold axes. The zigzag nature of the chains, which run along the [101] direction (Fig. 2), can be traced to the O3—Zn1—O3 and C1—S1—S1 angles of 99.67 (12) and 104.04 (17)°, respectively. The two benzene ring planes in the each DSDC ligand are almost perpendicular, with a dihedral angle of 80.99 (7)°, imparting a slight twist to the chains. The carboxylate group is not coplanar with the aromatic ring to which it is attached but is twisted from the mean plane through the aromatic ring by 21.7(s.u.?)°.

As illustrated in Figs. 2 and 3, a major structural feature of (I) is the connection of adjacent zigzag chains via O—H···O hydrogen bonds. The water H atoms participate in hydrogen bonds with different carboxylate O atoms as acceptors, O1W—H1···O3 and O1W—H2···O2, to form a three-dimensional framework (Fig. 3). [From the Co-Editor: Please replace or merge Figs. 2 and 3 because of changes to the text.]

Related literature

For related literature, see: Atwood et al. (1996); Barton et al. (1999); Chui et al. (1999); He et al. (2006); Li et al. (1999); Lo et al. (2000); Monge et al. (2005); Wang et al. (2006); Zhang et al. (2004).

S2. Experimental

Zn(CH₃CO₂)₂·2H₂O (0.111 g, 0.5 mmol), 4,4'-sulfonylbis(methyl benzoate) (0.168 g, 0.5 mmol) and NaOH (0.039 g, 1 mmol) in a 1:1:2 molar ratio, with water (15 ml), were placed in a 25 ml Teflon-lined stainless steel reactor and heated to 453 K for 76 h. When the reactor was cooled to room temperature over a period of 3 d, colourless prismatic [From the Co-Editor: Please specify the type of prism] single crystals of (I) suitable for X-ray diffraction were obtained.

S3. Refinement

All H atoms were placed in calculated positions [From the Co-Editor: Not possible for water H atoms - please clarify] and refined with isotropic displacement parameters, using a riding model. [From the Co-Editor: Not possible for water H atoms - please clarify.]

From the Co-Editor: Please explain why the two O—H distances are so different. Please also supply details of O—H and C—H distances and U_iso(H) restraints used.

Computing details

Data collection: SMART (Siemens, 1996); cell refinement: SAINT (Siemens, 1994); data reduction: SAINT and SHELXTL (Siemens, 1995); program(s) used to solve structure: SHELXTL; program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Figures

	Fig. 1. The structure of (I), showing the atom-numbering scheme. Displacement ellipsoids are plotted at the 30% probability level. [Symmetry codes: (a) -1 - x, y, -3/2 - z; (b) -x, y, -1/2 - z; (c) 1 + x, y, 1 + z.]
	Fig. 2. A view of (I), showing how the chains are linked by hydrogen bonding into a three-dimensional network. Hydrogen bonds are depicted as dashed lines.
	Fig. 3. The network structure of (I), as seen from an alternative viewpoint. Hydrogen bonds are depicted as dashed lines.

catena-Poly[[diaquazinc(II)]-µ-4,4'-sulfonyldibenzoato-κ²O:O']

Crystal data

[Zn(C14H8O6S)(H2O)2]	F(000) = 412
Mr = 405.70	Dx = 1.851 Mg m^−3
Monoclinic, P2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yc	Cell parameters from 310 reflections
a = 13.307 (2) Å	θ = 3.4–27.5°
b = 5.0336 (5) Å	µ = 1.87 mm^−1
c = 12.1142 (18) Å	T = 293 K
β = 116.218 (5)°	Prism, colourless
V = 727.95 (17) Å^3	0.30 × 0.10 × 0.03 mm
Z = 2

Data collection

Bruker P4 diffractometer	1668 independent reflections
Radiation source: fine-focus sealed tube	1454 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.034
ω scans	θmax = 27.5°, θmin = 3.4°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −16→17
Tmin = 0.799, Tmax = 0.945	k = −6→6
5356 measured reflections	l = −15→15

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)] = 0.037	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.090	H-atom parameters constrained
S = 1.02	w = 1/[σ^2(Fo^2) + (0.0449P)^2 + 0.496P] where P = (Fo^2 + 2Fc^2)/3
1668 reflections	(Δ/σ)max = 0.002
110 parameters	Δρmax = 0.35 e Å^−3
0 restraints	Δρmin = −0.43 e Å^−3

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.

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

	x	y	z	Uiso*/Ueq
Zn1	0.5000	0.06544 (8)	0.2500	0.02921 (16)
S1	1.0000	1.11920 (17)	0.7500	0.0245 (2)
O1	0.95911 (16)	1.2624 (4)	0.82475 (17)	0.0333 (5)
O1W	0.43397 (19)	−0.2093 (4)	0.31598 (18)	0.0404 (5)
H1	0.4431	−0.1668	0.3851	0.048*
H2	0.4124	−0.3601	0.2709	0.048*
O2	0.57593 (17)	0.2490 (4)	0.46605 (18)	0.0369 (5)
O3	0.62737 (16)	0.3210 (4)	0.32013 (16)	0.0315 (4)
C1	0.8918 (2)	0.9027 (5)	0.6537 (2)	0.0246 (5)
C2	0.8021 (2)	0.8548 (6)	0.6798 (2)	0.0297 (6)
H2A	0.7975	0.9384	0.7458	0.036*
C3	0.7191 (2)	0.6793 (6)	0.6053 (2)	0.0305 (6)
H3A	0.6583	0.6447	0.6216	0.037*
C4	0.7264 (2)	0.5561 (5)	0.5072 (2)	0.0249 (5)
C5	0.8155 (2)	0.6106 (6)	0.4804 (2)	0.0310 (6)
H5A	0.8191	0.5317	0.4128	0.037*
C6	0.8991 (2)	0.7828 (6)	0.5548 (2)	0.0307 (6)
H6A	0.9597	0.8178	0.5384	0.037*
C7	0.6383 (2)	0.3636 (5)	0.4294 (2)	0.0268 (6)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Zn1	0.0281 (3)	0.0200 (2)	0.0372 (3)	0.000	0.0123 (2)	0.000
S1	0.0232 (5)	0.0219 (4)	0.0243 (4)	0.000	0.0069 (4)	0.000
O1	0.0320 (10)	0.0287 (10)	0.0365 (10)	0.0021 (8)	0.0128 (9)	−0.0074 (8)
O1W	0.0640 (15)	0.0269 (10)	0.0353 (11)	−0.0108 (10)	0.0266 (11)	−0.0061 (8)
O2	0.0371 (11)	0.0358 (11)	0.0342 (11)	−0.0115 (9)	0.0124 (9)	−0.0005 (9)
O3	0.0330 (11)	0.0312 (10)	0.0270 (10)	−0.0038 (8)	0.0102 (9)	−0.0073 (8)
C1	0.0249 (13)	0.0226 (12)	0.0225 (12)	0.0002 (10)	0.0070 (11)	0.0003 (10)
C2	0.0323 (15)	0.0319 (14)	0.0276 (13)	−0.0043 (12)	0.0158 (12)	−0.0078 (11)
C3	0.0290 (14)	0.0343 (14)	0.0316 (14)	−0.0069 (12)	0.0166 (12)	−0.0055 (11)
C4	0.0257 (13)	0.0216 (12)	0.0234 (12)	0.0002 (10)	0.0071 (11)	0.0004 (10)
C5	0.0329 (15)	0.0348 (15)	0.0264 (14)	−0.0041 (12)	0.0141 (12)	−0.0065 (11)
C6	0.0294 (14)	0.0363 (15)	0.0291 (13)	−0.0060 (12)	0.0154 (12)	−0.0043 (11)
C7	0.0266 (14)	0.0221 (12)	0.0246 (13)	0.0046 (10)	0.0049 (11)	0.0019 (10)

Geometric parameters (Å, º)

Zn1—O1W^i	1.986 (2)	O2—C7	1.243 (3)
Zn1—O1W	1.986 (2)	O3—C7	1.284 (3)
Zn1—O3	1.9942 (19)	C1—C6	1.382 (4)
Zn1—O3^i	1.9942 (19)	C1—C2	1.384 (4)
Zn1—O2	2.528 (2)	C2—C3	1.391 (4)
Zn1—O2^i	2.528 (2)	C2—H2A	0.9300
Zn1—C7	2.613 (3)	C3—C4	1.382 (4)
Zn1—C7^i	2.613 (3)	C3—H3A	0.9300
S1—O1^ii	1.4391 (19)	C4—C5	1.388 (4)
S1—O1	1.4391 (19)	C4—C7	1.492 (4)
S1—C1	1.771 (3)	C5—C6	1.384 (4)
S1—C1^ii	1.771 (3)	C5—H5A	0.9300
O1W—H1	0.8199	C6—H6A	0.9300
O1W—H2	0.9045
O1W^i—Zn1—O1W	91.73 (12)	O1—S1—C1^ii	108.49 (11)
O1W^i—Zn1—O3	100.18 (9)	C1—S1—C1^ii	104.04 (17)
O1W—Zn1—O3	136.19 (8)	Zn1—O1W—H1	109.7
O1W^i—Zn1—O3^i	136.19 (8)	Zn1—O1W—H2	114.8
O1W—Zn1—O3^i	100.18 (9)	H1—O1W—H2	134.4
O3—Zn1—O3^i	99.67 (11)	C7—O2—Zn1	79.87 (15)
O1W^i—Zn1—O2	128.74 (8)	C7—O3—Zn1	103.57 (17)
O1W—Zn1—O2	83.30 (7)	C6—C1—C2	121.3 (2)
O3—Zn1—O2	56.45 (7)	C6—C1—S1	119.5 (2)
O3^i—Zn1—O2	94.65 (7)	C2—C1—S1	119.28 (19)
O1W^i—Zn1—O2^i	83.30 (7)	C1—C2—C3	118.8 (2)
O1W—Zn1—O2^i	128.74 (8)	C1—C2—H2A	120.6
O3—Zn1—O2^i	94.65 (7)	C3—C2—H2A	120.6
O3^i—Zn1—O2^i	56.45 (7)	C4—C3—C2	120.3 (3)
O2—Zn1—O2^i	137.11 (9)	C4—C3—H3A	119.8
O1W^i—Zn1—C7	117.42 (9)	C2—C3—H3A	119.8
O1W—Zn1—C7	109.85 (8)	C3—C4—C5	120.3 (2)
O3—Zn1—C7	28.54 (8)	C3—C4—C7	120.0 (2)
O3^i—Zn1—C7	97.91 (8)	C5—C4—C7	119.7 (2)
O2—Zn1—C7	27.91 (7)	C6—C5—C4	119.7 (2)
O2^i—Zn1—C7	117.62 (8)	C6—C5—H5A	120.2
O1W^i—Zn1—C7^i	109.85 (8)	C4—C5—H5A	120.2
O1W—Zn1—C7^i	117.42 (9)	C5—C6—C1	119.6 (3)
O3—Zn1—C7^i	97.91 (8)	C5—C6—H6A	120.2
O3^i—Zn1—C7^i	28.54 (8)	C1—C6—H6A	120.2
O2—Zn1—C7^i	117.62 (8)	O2—C7—O3	120.1 (2)
O2^i—Zn1—C7^i	27.91 (7)	O2—C7—C4	122.6 (2)
C7—Zn1—C7^i	109.89 (11)	O3—C7—C4	117.3 (2)
O1^ii—S1—O1	119.88 (17)	O2—C7—Zn1	72.22 (15)
O1^ii—S1—C1	108.49 (11)	O3—C7—Zn1	47.89 (13)
O1—S1—C1	107.42 (12)	C4—C7—Zn1	165.2 (2)
O1^ii—S1—C1^ii	107.42 (11)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1W—H1···O2^iii	0.82	1.97	2.709 (3)	149
O1W—H2···O3^iv	0.90	1.89	2.790 (3)	178

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