Hexa­aqua­copper(II) 3-carboxy-4-hydroxy­benzene­sulfonate dihydrate

In the title compound, [Cu(H₂O)₆]L₂·2H₂O, where HL = 3-carboxy-4-hydroxy­benzene­sulfonic acid (C₇H₆O₆S), each Cu^II cation lies on an inversion center and is octahedrally coordinated by six water mol­ecules. The L^- anions do not coordinate to copper, but act as counter-anions. The crystal structure is composed of alternating layers of [Cu(H₂O)₆]²⁺ cations and sulfonate anions. The [Cu(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) = 0.003 Å
• R factor = 0.032
• wR factor = 0.093
• Data-to-parameter ratio = 12.5

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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) and nickel compound (Ma et al., 2003c) have been reported in the preceding papers. The crystal structure of the copper compound, (I), is presented here. The crystal structure of the related zinc compound is reported in the following paper.

The Cu^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 Cu^II cation. Each Cu^II cation is coordinated by six water molecules, like the Mn(II) cation of the manganese compound (Ma et al., 2003a). Due to the Jahn–Teller effect, the Cu1—Ow1 distance, 2.4175 (18) Å, is much longer than those for Cu1—Ow2, 1.9527 (18) Å, and Cu1—Ow3, 1.9596 (18) Å.

The crystal structure of (I) is composed of alternating layers of [Cu(H₂O)₆]²⁺ cations and sulfonate anions, as shown in Fig. 2. Within the sulfonate layer, there are rows of anions with alternating orientations of the organic group. The phenyl ring is almost perpendicular to the the layer of cations with a dihedral angle of 86.3°, which is larger than the value for the manganese compound, 78.2° (Ma et al., 2003a).

The [Cu(H₂O)₆]²⁺ cations, water molecules and L⁻ anions are connected through a complex pattern of hydrogen-bonding interactions. 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 CuO (0.080 g, 1 mmol) in water (10 ml) was stirred at room temperature for 30 min. Blue crystals of compound (I) were obtained after leaving the solution to stand at room temperature for several days. Analysis calculated for C₁₄H₂₆CuO₂₀S₂: C 26.19, H 4.08%; found: C 26.25, H 4.03%.

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 of Cu^II, 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 b axis.

(I)

Crystal data

[Cu(H2O)6](C7H5O6S)2·2H2O	Z = 1
Mr = 642.01	F(000) = 331
Triclinic, P1	Dx = 1.744 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 7.0298 (9) Å	Cell parameters from 20 reflections
b = 7.0749 (15) Å	θ = 5.4–9.9°
c = 13.288 (4) Å	µ = 1.16 mm^−1
α = 92.16 (2)°	T = 293 K
β = 90.259 (18)°	Block, blue
γ = 112.236 (12)°	0.50 × 0.36 × 0.34 mm
V = 611.2 (2) Å^3

Data collection

Siemens P4 diffractometer	Rint = 0.017
Radiation source: fine-focus sealed tube	θmax = 26.0°, θmin = 1.5°
Graphite monochromator	h = −1→8
ω scans	k = −8→8
3134 measured reflections	l = −16→16
2413 independent reflections	3 standard reflections every 97 reflections
2140 reflections with I > 2σ(I)	intensity decay: none

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)] = 0.032	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.093	H atoms treated by a mixture of independent and constrained refinement
S = 1.10	w = 1/[σ^2(Fo^2) + (0.0566P)^2] where P = (Fo^2 + 2Fc^2)/3
2413 reflections	(Δ/σ)max < 0.001
193 parameters	Δρmax = 0.30 e Å^−3
8 restraints	Δρmin = −0.52 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.

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	0.2205 (3)	0.4403 (3)	0.65438 (15)	0.0244 (4)
C2	0.2004 (3)	0.3313 (3)	0.56410 (15)	0.0243 (4)
H2	0.1638	0.1904	0.5634	0.029*
C3	0.2352 (3)	0.4327 (3)	0.47369 (15)	0.0241 (4)
C4	0.2928 (4)	0.6457 (4)	0.47607 (17)	0.0284 (5)
C5	0.3103 (4)	0.7531 (3)	0.56800 (18)	0.0322 (5)
H5	0.3472	0.8941	0.5695	0.039*
C6	0.2734 (4)	0.6517 (3)	0.65644 (17)	0.0301 (5)
H6	0.2835	0.7237	0.7176	0.036*
C7	0.2117 (4)	0.3171 (4)	0.37601 (17)	0.0305 (5)
O1	0.3123 (3)	0.1933 (3)	0.76643 (13)	0.0416 (5)
O2	−0.0378 (3)	0.1691 (2)	0.76838 (12)	0.0308 (4)
O3	0.2249 (3)	0.4634 (3)	0.84896 (12)	0.0444 (5)
O4	0.1564 (3)	0.1200 (3)	0.38535 (12)	0.0418 (5)
H4	0.1452	0.0634	0.3294	0.063*
O5	0.2416 (4)	0.3988 (3)	0.29508 (12)	0.0467 (5)
O6	0.3330 (3)	0.7531 (3)	0.39242 (14)	0.0448 (5)
H6A	0.3181	0.6754	0.3431	0.067*
OW1	0.6723 (3)	0.2571 (3)	0.88095 (12)	0.0317 (4)
OW2	0.4356 (3)	0.1959 (3)	1.08673 (14)	0.0378 (4)
OW3	0.2426 (3)	−0.0653 (3)	0.92333 (14)	0.0378 (4)
OW4	0.8673 (3)	0.6598 (3)	0.95578 (13)	0.0338 (4)
S1	0.17750 (9)	0.30792 (8)	0.76709 (4)	0.02569 (16)
Cu1	0.5000	0.0000	1.0000	0.02392 (14)
H1A	0.766 (4)	0.237 (4)	0.8420 (19)	0.036*
H1B	0.577 (4)	0.252 (4)	0.8364 (18)	0.036*
H2A	0.540 (4)	0.304 (3)	1.109 (2)	0.036*
H2B	0.339 (4)	0.239 (4)	1.071 (2)	0.036*
H3A	0.121 (3)	−0.157 (4)	0.936 (2)	0.036*
H3B	0.222 (4)	−0.015 (4)	0.8674 (16)	0.036*
H4A	0.854 (4)	0.621 (4)	1.0185 (15)	0.036*
H4B	0.819 (4)	0.545 (3)	0.9187 (18)	0.036*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0243 (11)	0.0238 (10)	0.0227 (10)	0.0063 (9)	−0.0005 (8)	0.0025 (8)
C2	0.0254 (11)	0.0200 (10)	0.0252 (10)	0.0057 (9)	−0.0013 (9)	0.0012 (8)
C3	0.0234 (11)	0.0242 (11)	0.0225 (10)	0.0064 (9)	0.0005 (8)	0.0020 (8)
C4	0.0256 (12)	0.0290 (11)	0.0301 (11)	0.0092 (9)	0.0015 (9)	0.0091 (9)
C5	0.0387 (14)	0.0182 (10)	0.0387 (12)	0.0095 (10)	−0.0005 (11)	0.0009 (9)
C6	0.0343 (13)	0.0247 (11)	0.0283 (11)	0.0084 (10)	−0.0016 (10)	−0.0053 (8)
C7	0.0265 (12)	0.0334 (12)	0.0261 (11)	0.0052 (10)	−0.0003 (9)	0.0004 (9)
O1	0.0390 (11)	0.0545 (12)	0.0377 (9)	0.0231 (9)	0.0038 (8)	0.0196 (8)
O2	0.0283 (9)	0.0295 (8)	0.0276 (8)	0.0034 (7)	0.0025 (7)	−0.0023 (6)
O3	0.0568 (13)	0.0339 (9)	0.0229 (8)	−0.0043 (9)	−0.0022 (8)	−0.0050 (7)
O4	0.0582 (13)	0.0291 (9)	0.0278 (8)	0.0058 (9)	0.0037 (8)	−0.0083 (7)
O5	0.0675 (14)	0.0458 (11)	0.0217 (8)	0.0155 (10)	0.0049 (8)	0.0043 (7)
O6	0.0637 (14)	0.0354 (10)	0.0351 (9)	0.0171 (10)	0.0081 (9)	0.0148 (7)
OW1	0.0306 (9)	0.0335 (9)	0.0317 (8)	0.0130 (8)	0.0021 (7)	0.0023 (7)
OW2	0.0317 (10)	0.0322 (9)	0.0490 (10)	0.0132 (8)	−0.0053 (8)	−0.0143 (8)
OW3	0.0268 (9)	0.0374 (10)	0.0413 (9)	0.0021 (8)	−0.0092 (8)	0.0139 (8)
OW4	0.0344 (10)	0.0301 (9)	0.0315 (8)	0.0067 (8)	0.0005 (7)	−0.0037 (7)
S1	0.0267 (3)	0.0267 (3)	0.0189 (3)	0.0047 (2)	−0.0018 (2)	0.0008 (2)
Cu1	0.0228 (2)	0.0199 (2)	0.0276 (2)	0.00665 (16)	−0.00385 (15)	−0.00162 (14)

Geometric parameters (Å, º)

C1—C2	1.379 (3)	O4—H4	0.820
C1—C6	1.397 (3)	O6—H6A	0.820
C1—S1	1.763 (2)	OW1—Cu1	2.4175 (18)
C2—C3	1.397 (3)	OW1—H1A	0.888 (18)
C2—H2	0.930	OW1—H1B	0.884 (18)
C3—C4	1.403 (3)	OW2—Cu1	1.9527 (18)
C3—C7	1.482 (3)	OW2—H2A	0.876 (18)
C4—O6	1.340 (3)	OW2—H2B	0.873 (17)
C4—C5	1.394 (3)	OW3—Cu1	1.9596 (18)
C5—C6	1.374 (3)	OW3—H3A	0.879 (18)
C5—H5	0.930	OW3—H3B	0.871 (17)
C6—H6	0.930	OW4—H4A	0.882 (17)
C7—O5	1.221 (3)	OW4—H4B	0.879 (18)
C7—O4	1.310 (3)	Cu1—OW2^i	1.9527 (18)
O1—S1	1.462 (2)	Cu1—OW3^i	1.9596 (18)
O2—S1	1.4600 (17)	Cu1—OW1^i	2.4175 (18)
O3—S1	1.4608 (18)
C2—C1—C6	120.6 (2)	Cu1—OW2—H2B	122.3 (19)
C2—C1—S1	118.77 (17)	H2A—OW2—H2B	106 (3)
C6—C1—S1	120.64 (17)	Cu1—OW3—H3A	127.8 (19)
C1—C2—C3	119.9 (2)	Cu1—OW3—H3B	128.5 (19)
C1—C2—H2	120.0	H3A—OW3—H3B	104 (3)
C3—C2—H2	120.0	H4A—OW4—H4B	105 (3)
C2—C3—C4	119.39 (19)	O2—S1—O3	111.03 (11)
C2—C3—C7	120.5 (2)	O2—S1—O1	110.55 (11)
C4—C3—C7	120.11 (19)	O3—S1—O1	113.44 (13)
O6—C4—C5	117.6 (2)	O2—S1—C1	108.60 (10)
O6—C4—C3	122.5 (2)	O3—S1—C1	106.18 (10)
C5—C4—C3	119.9 (2)	O1—S1—C1	106.73 (11)
C6—C5—C4	120.3 (2)	OW2^i—Cu1—OW2	180.0
C6—C5—H5	119.8	OW2^i—Cu1—OW3	89.33 (8)
C4—C5—H5	119.8	OW2—Cu1—OW3	90.67 (8)
C5—C6—C1	119.9 (2)	OW2^i—Cu1—OW3^i	90.67 (8)
C5—C6—H6	120.1	OW2—Cu1—OW3^i	89.33 (8)
C1—C6—H6	120.1	OW3—Cu1—OW3^i	180.0
O5—C7—O4	123.6 (2)	OW2^i—Cu1—OW1	87.81 (7)
O5—C7—C3	123.0 (2)	OW2—Cu1—OW1	92.19 (7)
O4—C7—C3	113.37 (19)	OW3—Cu1—OW1	89.13 (7)
C7—O4—H4	109.5	OW3^i—Cu1—OW1	90.87 (7)
C4—O6—H6A	109.5	OW2^i—Cu1—OW1^i	92.19 (7)
Cu1—OW1—H1A	117.9 (18)	OW2—Cu1—OW1^i	87.81 (7)
Cu1—OW1—H1B	105.7 (19)	OW3—Cu1—OW1^i	90.87 (7)
H1A—OW1—H1B	102 (3)	OW3^i—Cu1—OW1^i	89.13 (7)
Cu1—OW2—H2A	116 (2)	OW1—Cu1—OW1^i	180.0
C6—C1—C2—C3	0.7 (4)	S1—C1—C6—C5	178.72 (19)
S1—C1—C2—C3	−179.52 (17)	C2—C3—C7—O5	−179.5 (2)
C1—C2—C3—C4	0.8 (3)	C4—C3—C7—O5	0.5 (4)
C1—C2—C3—C7	−179.2 (2)	C2—C3—C7—O4	0.3 (3)
C2—C3—C4—O6	178.5 (2)	C4—C3—C7—O4	−179.7 (2)
C7—C3—C4—O6	−1.5 (4)	C2—C1—S1—O2	−64.7 (2)
C2—C3—C4—C5	−1.4 (4)	C6—C1—S1—O2	115.0 (2)
C7—C3—C4—C5	178.6 (2)	C2—C1—S1—O3	175.79 (19)
O6—C4—C5—C6	−179.3 (2)	C6—C1—S1—O3	−4.4 (2)
C3—C4—C5—C6	0.6 (4)	C2—C1—S1—O1	54.5 (2)
C4—C5—C6—C1	0.8 (4)	C6—C1—S1—O1	−125.7 (2)
C2—C1—C6—C5	−1.5 (4)

Symmetry code: (i) −x+1, −y, −z+2.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
OW1—H1A···O2^ii	0.89 (2)	1.89 (2)	2.774 (2)	173 (3)
OW1—H1B···O1	0.88 (2)	1.97 (2)	2.824 (3)	164 (3)
OW2—H2A···O3^iii	0.88 (2)	1.90 (2)	2.777 (3)	177 (3)
OW2—H2B···OW4^iii	0.87 (2)	1.88 (2)	2.752 (3)	177 (3)
OW3—H3A···OW4^iv	0.88 (2)	1.79 (2)	2.668 (3)	177 (3)
OW3—H3B···O1	0.87 (2)	1.95 (2)	2.748 (3)	151 (3)
OW4—H4A···O3^iii	0.88 (2)	1.90 (2)	2.770 (3)	169 (3)
OW4—H4B···OW1	0.88 (2)	1.95 (2)	2.794 (3)	160 (3)
O4—H4···O2^v	0.82	1.96	2.726 (2)	154
O6—H6A···O5	0.82	1.91	2.627 (3)	146

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