Hexa­aqua­zinc(II) 3-carboxy-4-hydroxy­benzene­sulfonate tetrahydrate

In the title compound, [Zn(H₂O)₆]L₂·4H₂O, where HL = 3-carboxy-4-hydroxy­benzene­sulfonic acid (C₇H₆O₆S), each Zn^II cation lies on an inversion center and is octahedrally coordinated by six water mol­ecules. The L^- anions do not coordinate to zinc, but act as counter-anions. The crystal structure is composed of alternating layers of [Zn(H₂O)₆]²⁺ cations and sulfonate anions. The [Zn(H₂O)₆]²⁺ cations, water mol­ecules and L^- anions are connected through a complex pattern of hydrogen-bonding interactions.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.004 Å
• R factor = 0.033
• wR factor = 0.088
• Data-to-parameter ratio = 12.5

checkCIF results

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S1. Comment

The crystal structures of five transition metal (Mn, Co, Ni, Cu and Zn) 3-carboxy-4-hydroxybenzenesulfonates have been determined. The structures of the manganese (Ma et al., 2003a), cobalt (Ma et al., 2003b), nickel (Ma et al., 2003c) and copper compound (Ma et al., 2003 d) have been reported in the preceding papers. The crystal structure of the zinc compound, (I), is presented here.

The Zn^II atom is located on an inversion center, and all other atoms are in general positions. Selected bond lengths and angles are given in Table 1. Fig. 1 shows the asymmetric unit, together with the complete coordination environment of the Zn^II cation. Compound (I) is isostructural with the cobalt compound (Ma et al., 2003b) and nickel compound (Ma et al., 2003c). The Zn—O distances range from 2.059 (2) to 2.099 (2) Å. The average Zn—O distance of 2.082 Å is slightly shorter than the values in other zinc compounds (Li et al., 2002).

The alternating layers of [Zn(H₂O)₆]²⁺ cations and sulfonate anions in (I) are shown in Fig.2. Selected hydrogen-bond parameters are listed in Table 2.

S2. Experimental

A mixture of 3-carboxy-4-hydroxybenzenesulfonic acid (0.44 g, 2 mmol) and ZnO (0.081 g, 1 mmol) in water (10 ml) was stirred at room temperature for 30 min. Colorless crystals of compound (I) were obtained after leaving the solution to stand at room temperature for several days. Analysis calculated for C₁₄H₃₀CoO₂₂S₂: C 24.73, H 4.45%; found: C 24.59, H 4.39%.

S3. Refinement

All H atoms on C atoms were positioned geometrically and refined as riding atoms, with C—H = 0.93 Å and U_iso(H) = 1.2U_eq(C). The H atoms of the carboxyl group and hydroxyl group were also positioned geometrically and refined as riding atoms, with O—H = 0.82 Å and U_iso(H) = 1.5U_eq(O). The water H atoms were located in a difference Fourier map and refined with U_iso(H) = 1.5U_eq(O).

Computing details

Data collection: XSCANS (Siemens, 1994); cell refinement: XSCANS; data reduction: XSCANS; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL-Plus (Sheldrick, 1990); software used to prepare material for publication: SHELXL97.

Figures

	Fig. 1. View of the asymmetric unit, expanded to show the complete coordination, with the atomic numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.
	Fig. 2. View of the alternating layers of cations and anions, along the a axis.

(I)

Crystal data

[Zn(H2O)6](C7H5O6S)2·4H2O	Z = 1
Mr = 679.87	F(000) = 352
Triclinic, P1	Dx = 1.685 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 6.5367 (14) Å	Cell parameters from 22 reflections
b = 7.2555 (18) Å	θ = 4.8–8.7°
c = 14.616 (4) Å	µ = 1.17 mm^−1
α = 92.83 (2)°	T = 293 K
β = 96.321 (19)°	Block, colorless
γ = 102.839 (17)°	0.52 × 0.36 × 0.32 mm
V = 669.8 (3) Å^3

Data collection

Siemens P4 diffractometer	2101 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.020
Graphite monochromator	θmax = 26.0°, θmin = 2.8°
ω scans	h = −1→8
Absorption correction: ψ scan (North et al., 1968)	k = −8→8
Tmin = 0.517, Tmax = 0.688	l = −17→17
3445 measured reflections	3 standard reflections every 97 reflections
2615 independent reflections	intensity decay: none

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.033	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.088	w = 1/[σ^2(Fo^2) + (0.0454P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 1.03	(Δ/σ)max < 0.001
2615 reflections	Δρmax = 0.51 e Å^−3
209 parameters	Δρmin = −0.29 e Å^−3
10 restraints	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.083 (4)

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 > σ(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
C1	0.4006 (4)	0.1612 (3)	0.35540 (16)	0.0273 (5)
C2	0.3128 (4)	0.1613 (3)	0.43725 (16)	0.0283 (5)
H2	0.1692	0.1104	0.4375	0.034*
C3	0.4389 (4)	0.2375 (3)	0.51942 (16)	0.0277 (5)
C4	0.6548 (4)	0.3158 (3)	0.51830 (17)	0.0304 (5)
C5	0.7415 (4)	0.3125 (4)	0.43528 (18)	0.0370 (6)
H5	0.8853	0.3620	0.4346	0.044*
C6	0.6161 (4)	0.2367 (4)	0.35449 (17)	0.0352 (6)
H6A	0.6748	0.2357	0.2994	0.042*
C7	0.3455 (4)	0.2393 (4)	0.60727 (17)	0.0324 (6)
O1	0.0984 (4)	0.2068 (3)	0.23376 (15)	0.0558 (6)
O2	0.3650 (3)	0.0564 (3)	0.18078 (13)	0.0519 (6)
O3	0.1035 (3)	−0.1103 (2)	0.26922 (12)	0.0398 (5)
O4	0.1419 (3)	0.1632 (3)	0.59701 (13)	0.0488 (5)
H4	0.0974	0.1665	0.6472	0.073*
O5	0.4479 (3)	0.3045 (3)	0.68175 (12)	0.0455 (5)
O6	0.7842 (3)	0.3981 (3)	0.59463 (13)	0.0443 (5)
H6	0.7171	0.3917	0.6390	0.066*
OW1	0.7107 (4)	0.3358 (3)	0.97543 (15)	0.0553 (6)
OW2	0.7260 (4)	0.7416 (3)	0.97855 (13)	0.0440 (5)
OW3	0.6201 (3)	0.5266 (3)	1.14047 (13)	0.0448 (5)
OW4	0.7399 (3)	0.0528 (3)	0.09920 (14)	0.0465 (5)
OW5	0.9507 (4)	0.4486 (3)	0.83240 (14)	0.0469 (5)
S1	0.23299 (10)	0.07286 (9)	0.25194 (4)	0.03017 (18)
Zn1	0.5000	0.5000	1.0000	0.03347 (17)
H1A	0.744 (5)	0.245 (4)	1.0092 (19)	0.050*
H1B	0.803 (4)	0.363 (4)	0.9370 (19)	0.050*
H2A	0.740 (5)	0.839 (3)	1.0199 (18)	0.050*
H2B	0.712 (5)	0.793 (4)	0.9263 (15)	0.050*
H3A	0.758 (3)	0.536 (4)	1.150 (2)	0.050*
H3B	0.597 (5)	0.604 (4)	1.1840 (18)	0.050*
H4A	0.615 (4)	0.028 (4)	0.122 (2)	0.050*
H4B	0.844 (4)	0.098 (4)	0.1448 (17)	0.050*
H5A	0.896 (5)	0.347 (3)	0.7974 (19)	0.050*
H5B	0.915 (5)	0.546 (3)	0.812 (2)	0.050*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0306 (13)	0.0270 (12)	0.0240 (11)	0.0057 (10)	0.0038 (10)	0.0030 (9)
C2	0.0257 (12)	0.0303 (12)	0.0285 (12)	0.0046 (10)	0.0047 (10)	0.0025 (10)
C3	0.0309 (12)	0.0272 (12)	0.0260 (12)	0.0078 (10)	0.0061 (10)	0.0015 (9)
C4	0.0288 (13)	0.0314 (13)	0.0297 (12)	0.0053 (10)	0.0012 (10)	0.0022 (10)
C5	0.0259 (13)	0.0424 (15)	0.0383 (14)	−0.0017 (11)	0.0051 (11)	0.0004 (11)
C6	0.0343 (14)	0.0414 (15)	0.0302 (13)	0.0045 (12)	0.0120 (11)	0.0062 (11)
C7	0.0364 (14)	0.0337 (13)	0.0284 (12)	0.0103 (11)	0.0073 (11)	−0.0012 (10)
O1	0.0630 (14)	0.0474 (12)	0.0551 (13)	0.0224 (11)	−0.0184 (11)	−0.0001 (10)
O2	0.0455 (12)	0.0791 (15)	0.0271 (9)	0.0014 (11)	0.0149 (9)	−0.0001 (9)
O3	0.0465 (11)	0.0385 (10)	0.0286 (9)	−0.0049 (9)	0.0117 (8)	−0.0028 (8)
O4	0.0367 (11)	0.0724 (15)	0.0316 (10)	−0.0018 (10)	0.0142 (8)	−0.0088 (9)
O5	0.0445 (12)	0.0647 (13)	0.0251 (9)	0.0102 (10)	0.0025 (8)	−0.0041 (9)
O6	0.0352 (10)	0.0575 (13)	0.0333 (10)	0.0007 (9)	−0.0026 (8)	−0.0030 (9)
OW1	0.0723 (16)	0.0613 (14)	0.0501 (13)	0.0399 (13)	0.0284 (12)	0.0175 (11)
OW2	0.0590 (13)	0.0421 (11)	0.0285 (10)	0.0040 (10)	0.0090 (10)	0.0053 (8)
OW3	0.0459 (11)	0.0653 (14)	0.0245 (9)	0.0167 (11)	0.0052 (9)	−0.0033 (9)
OW4	0.0376 (11)	0.0581 (13)	0.0429 (11)	0.0118 (10)	0.0030 (9)	−0.0023 (10)
OW5	0.0583 (13)	0.0375 (11)	0.0440 (12)	0.0134 (10)	0.0012 (10)	−0.0042 (9)
S1	0.0337 (3)	0.0344 (4)	0.0214 (3)	0.0048 (3)	0.0042 (2)	0.0040 (2)
Zn1	0.0410 (3)	0.0373 (3)	0.0245 (2)	0.0119 (2)	0.00789 (18)	0.00306 (17)

Geometric parameters (Å, º)

C1—C2	1.383 (3)	O6—H6	0.820
C1—C6	1.395 (4)	OW1—Zn1	2.059 (2)
C1—S1	1.768 (2)	OW1—H1A	0.891 (18)
C2—C3	1.393 (3)	OW1—H1B	0.868 (18)
C2—H2	0.930	OW2—Zn1	2.088 (2)
C3—C4	1.401 (3)	OW2—H2A	0.889 (18)
C3—C7	1.482 (3)	OW2—H2B	0.870 (18)
C4—O6	1.349 (3)	OW3—Zn1	2.099 (2)
C4—C5	1.396 (4)	OW3—H3A	0.887 (18)
C5—C6	1.375 (3)	OW3—H3B	0.878 (18)
C5—H5	0.930	OW4—H4A	0.901 (18)
C6—H6A	0.930	OW4—H4B	0.890 (18)
C7—O5	1.227 (3)	OW5—H5A	0.859 (18)
C7—O4	1.311 (3)	OW5—H5B	0.846 (18)
O1—S1	1.463 (2)	Zn1—OW1^i	2.059 (2)
O2—S1	1.440 (2)	Zn1—OW2^i	2.088 (2)
O3—S1	1.4582 (18)	Zn1—OW3^i	2.099 (2)
O4—H4	0.820
C2—C1—C6	120.3 (2)	H2A—OW2—H2B	103 (3)
C2—C1—S1	118.77 (18)	Zn1—OW3—H3A	114 (2)
C6—C1—S1	120.91 (19)	Zn1—OW3—H3B	127 (2)
C1—C2—C3	120.2 (2)	H3A—OW3—H3B	104 (3)
C1—C2—H2	119.9	H4A—OW4—H4B	109 (3)
C3—C2—H2	119.9	H5A—OW5—H5B	113 (3)
C2—C3—C4	119.5 (2)	O2—S1—O3	112.10 (12)
C2—C3—C7	120.5 (2)	O2—S1—O1	113.37 (14)
C4—C3—C7	120.0 (2)	O3—S1—O1	109.74 (13)
O6—C4—C5	117.8 (2)	O2—S1—C1	107.70 (12)
O6—C4—C3	122.6 (2)	O3—S1—C1	106.94 (11)
C5—C4—C3	119.6 (2)	O1—S1—C1	106.62 (12)
C6—C5—C4	120.5 (2)	OW1—Zn1—OW1^i	180.0
C6—C5—H5	119.7	OW1—Zn1—OW2	89.56 (10)
C4—C5—H5	119.7	OW1^i—Zn1—OW2	90.44 (10)
C5—C6—C1	119.9 (2)	OW1—Zn1—OW2^i	90.44 (10)
C5—C6—H6A	120.1	OW1^i—Zn1—OW2^i	89.56 (10)
C1—C6—H6A	120.1	OW2—Zn1—OW2^i	180.0
O5—C7—O4	123.6 (2)	OW1—Zn1—OW3^i	91.40 (9)
O5—C7—C3	123.6 (2)	OW1^i—Zn1—OW3^i	88.60 (9)
O4—C7—C3	112.9 (2)	OW2—Zn1—OW3^i	90.05 (8)
C7—O4—H4	109.5	OW2^i—Zn1—OW3^i	89.95 (9)
C4—O6—H6	109.5	OW1—Zn1—OW3	88.60 (9)
Zn1—OW1—H1A	128 (2)	OW1^i—Zn1—OW3	91.40 (9)
Zn1—OW1—H1B	123 (2)	OW2—Zn1—OW3	89.95 (9)
H1A—OW1—H1B	108 (3)	OW2^i—Zn1—OW3	90.05 (8)
Zn1—OW2—H2A	115 (2)	OW3^i—Zn1—OW3	180.0
Zn1—OW2—H2B	118 (2)
C6—C1—C2—C3	0.2 (4)	S1—C1—C6—C5	177.0 (2)
S1—C1—C2—C3	−177.19 (18)	C2—C3—C7—O5	−179.9 (2)
C1—C2—C3—C4	0.7 (4)	C4—C3—C7—O5	−1.0 (4)
C1—C2—C3—C7	179.6 (2)	C2—C3—C7—O4	0.3 (3)
C2—C3—C4—O6	177.5 (2)	C4—C3—C7—O4	179.2 (2)
C7—C3—C4—O6	−1.4 (4)	C2—C1—S1—O2	−169.8 (2)
C2—C3—C4—C5	−1.5 (4)	C6—C1—S1—O2	12.8 (2)
C7—C3—C4—C5	179.6 (2)	C2—C1—S1—O3	−49.2 (2)
O6—C4—C5—C6	−177.7 (2)	C6—C1—S1—O3	133.4 (2)
C3—C4—C5—C6	1.3 (4)	C2—C1—S1—O1	68.2 (2)
C4—C5—C6—C1	−0.4 (4)	C6—C1—S1—O1	−109.2 (2)
C2—C1—C6—C5	−0.4 (4)

Symmetry code: (i) −x+1, −y+1, −z+2.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
OW1—H1A···OW4^ii	0.89 (2)	1.96 (2)	2.827 (3)	162 (3)
OW1—H1B···OW5	0.87 (2)	1.95 (2)	2.797 (3)	165 (3)
OW2—H2A···OW4^iii	0.89 (2)	1.89 (2)	2.775 (3)	173 (3)
OW2—H2B···O2^iv	0.87 (2)	2.04 (2)	2.889 (3)	167 (3)
OW3—H3A···OW5^v	0.89 (2)	1.87 (2)	2.754 (3)	178 (3)
OW3—H3B···O5^i	0.88 (2)	2.11 (2)	2.938 (3)	157 (3)
OW4—H4A···O2	0.90 (2)	1.97 (2)	2.845 (3)	163 (3)
OW4—H4B···O1^vi	0.89 (2)	1.98 (2)	2.866 (3)	173 (3)
OW5—H5A···O3^vii	0.86 (2)	1.93 (2)	2.738 (3)	155 (3)
OW5—H5B···O1^iv	0.85 (2)	1.96 (2)	2.796 (3)	167 (3)
O4—H4···O3^viii	0.82	1.88	2.653 (3)	156
O6—H6···O5	0.82	1.92	2.637 (3)	146

Symmetry codes: (i) −x+1, −y+1, −z+2; (ii) x, y, z+1; (iii) x, y+1, z+1; (iv) −x+1, −y+1, −z+1; (v) −x+2, −y+1, −z+2; (vi) x+1, y, z; (vii) −x+1, −y, −z+1; (viii) −x, −y, −z+1.