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

In the title compound, [Co(H₂O)₆]L₂·4H₂O, where HL = 3-carboxy-4-hydroxy­benzene­sulfonic acid (C₇H₆O₆S), each Co^II cation lies on an inversion center and is octahedrally coordinated by six water mol­ecules. The L^- anions do not coordinate to cobalt, but act as counter-anions. The crystal structure is composed of alternating layers of [Co(H₂O)₆]²⁺ cations and sulfonate anions. The [Co(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 = 0.041
• wR factor = 0.118
• 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 structure of the manganese compound has been reported in the preceding paper (Ma et al., 2003). The crystal structure of the cobalt compound, (I), is presented here. The crystal structures of the other three related compounds are reported in the following papers.

The Co^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 Co^II cation. The coordination of Co^II is similar to that of Mn^II (Ma et al., 2003). The distances from cobalt to oxygen range from 2.051 (2) to 2.113 (2) Å. The average Co—O distance of 2.083 Å is similar to the values in other cobalt compounds (Kosnic et al., 1992; Shubnell et al., 1994).

The crystal structure of (I) is composed of alternating layers of [Co(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 dihedral angle between the phenyl ring and the layer of cations is 80.4°, similar to the value of the manganese compound, 78.2° (Ma et al., 2003).

There are two additional, uncoordinated water molecules in the asymmetric unit. The [Co(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 CoCO₃ (0.12 g, 1 mmol) in water (10 ml) was stirred at room temperature for 30 min. Pink crystals of compound (I) were obtained after leaving the solution to stand at room temperature for several days. Analysis calculated for C₁₄H₃₀CoO₂₂S₂: C 24.97, H 4.49%; found: C 24.79, H 4.43%.

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 Co^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 a axis.

(I)

Crystal data

[Co(H2O)6](C7H5O6S)2·4H2O	Z = 1
Mr = 673.43	F(000) = 349
Triclinic, P1	Dx = 1.674 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 6.5281 (11) Å	Cell parameters from 21 reflections
b = 7.2358 (18) Å	θ = 4.9–9.8°
c = 14.627 (4) Å	µ = 0.89 mm^−1
α = 92.73 (2)°	T = 293 K
β = 96.274 (18)°	Block, pink
γ = 102.803 (16)°	0.50 × 0.42 × 0.40 mm
V = 667.9 (3) Å^3

Data collection

Siemens P4 diffractometer	Rint = 0.028
Radiation source: fine-focus sealed tube	θmax = 26.0°, θmin = 2.8°
Graphite monochromator	h = −1→8
ω scans	k = −8→8
3436 measured reflections	l = −18→18
2603 independent reflections	3 standard reflections every 97 reflections
2167 reflections with I > 2σ(I)	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)] = 0.041	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.118	w = 1/[σ^2(Fo^2) + (0.0737P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 1.10	(Δ/σ)max < 0.001
2603 reflections	Δρmax = 0.63 e Å^−3
209 parameters	Δρmin = −0.51 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: 0.191 (11)

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	0.4010 (4)	0.1611 (3)	0.35523 (17)	0.0296 (5)
C2	0.3134 (4)	0.1622 (3)	0.43735 (17)	0.0301 (5)
H2	0.1696	0.1118	0.4378	0.036*
C3	0.4402 (4)	0.2383 (3)	0.51908 (17)	0.0295 (5)
C4	0.6551 (4)	0.3162 (3)	0.51809 (18)	0.0317 (6)
C5	0.7429 (4)	0.3120 (4)	0.4354 (2)	0.0390 (6)
H5	0.8870	0.3609	0.4348	0.047*
C6	0.6169 (4)	0.2358 (4)	0.35467 (19)	0.0364 (6)
H6	0.6761	0.2342	0.2997	0.044*
C7	0.3451 (4)	0.2398 (4)	0.60674 (18)	0.0333 (6)
O1	0.1008 (4)	0.2065 (3)	0.23349 (17)	0.0570 (6)
O2	0.1035 (3)	−0.1110 (3)	0.26987 (13)	0.0411 (5)
O3	0.3669 (3)	0.0545 (4)	0.18131 (14)	0.0533 (6)
O4	0.1428 (3)	0.1644 (3)	0.59659 (14)	0.0491 (6)
H4	0.0981	0.1678	0.6467	0.074*
O5	0.4477 (3)	0.3050 (3)	0.68096 (13)	0.0473 (5)
O6	0.7846 (3)	0.3984 (3)	0.59433 (14)	0.0456 (5)
H6A	0.7166	0.3944	0.6384	0.068*
OW1	0.7133 (4)	0.3394 (3)	0.97548 (16)	0.0524 (6)
OW2	0.6192 (4)	0.5244 (3)	1.14137 (14)	0.0447 (5)
OW3	0.7235 (4)	0.7432 (3)	0.97796 (14)	0.0440 (5)
OW4	0.7426 (3)	0.0557 (3)	0.09898 (15)	0.0453 (5)
OW5	0.0501 (4)	0.5514 (3)	0.16781 (15)	0.0465 (5)
S1	0.23426 (10)	0.07203 (9)	0.25211 (4)	0.0316 (2)
Co1	0.5000	0.5000	1.0000	0.0321 (2)
H1A	0.766 (5)	0.253 (4)	1.007 (2)	0.048*
H1B	0.790 (5)	0.360 (4)	0.9303 (18)	0.048*
H2A	0.759 (3)	0.541 (5)	1.154 (2)	0.048*
H2B	0.593 (5)	0.604 (4)	1.1840 (19)	0.048*
H3A	0.736 (5)	0.840 (3)	1.0216 (18)	0.048*
H3B	0.705 (5)	0.801 (4)	0.9243 (16)	0.048*
H4A	0.616 (4)	0.026 (4)	0.119 (2)	0.048*
H4B	0.850 (4)	0.100 (4)	0.1445 (19)	0.048*
H5A	0.095 (5)	0.648 (3)	0.2079 (19)	0.048*
H5B	0.103 (5)	0.460 (4)	0.191 (2)	0.048*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0329 (13)	0.0302 (12)	0.0251 (12)	0.0054 (10)	0.0052 (10)	0.0021 (9)
C2	0.0297 (13)	0.0335 (12)	0.0273 (13)	0.0069 (10)	0.0052 (10)	0.0015 (10)
C3	0.0348 (13)	0.0298 (12)	0.0258 (12)	0.0097 (10)	0.0073 (10)	0.0017 (9)
C4	0.0317 (13)	0.0326 (13)	0.0301 (13)	0.0067 (10)	0.0020 (11)	0.0022 (10)
C5	0.0293 (13)	0.0445 (15)	0.0391 (15)	−0.0019 (11)	0.0077 (12)	0.0017 (12)
C6	0.0353 (14)	0.0428 (15)	0.0314 (14)	0.0050 (12)	0.0133 (12)	0.0041 (11)
C7	0.0376 (14)	0.0355 (13)	0.0275 (13)	0.0092 (11)	0.0066 (11)	−0.0016 (10)
O1	0.0643 (15)	0.0475 (12)	0.0564 (14)	0.0197 (11)	−0.0172 (12)	0.0002 (10)
O2	0.0491 (12)	0.0398 (10)	0.0297 (10)	−0.0022 (9)	0.0131 (9)	−0.0042 (8)
O3	0.0476 (13)	0.0810 (16)	0.0260 (10)	−0.0008 (11)	0.0162 (9)	−0.0011 (10)
O4	0.0394 (11)	0.0720 (15)	0.0297 (10)	−0.0020 (10)	0.0134 (9)	−0.0096 (10)
O5	0.0473 (12)	0.0661 (14)	0.0267 (10)	0.0112 (11)	0.0048 (9)	−0.0066 (9)
O6	0.0366 (11)	0.0606 (13)	0.0335 (11)	0.0027 (9)	−0.0020 (9)	−0.0040 (9)
OW1	0.0680 (15)	0.0573 (13)	0.0465 (13)	0.0338 (12)	0.0264 (12)	0.0140 (10)
OW2	0.0482 (12)	0.0633 (13)	0.0242 (10)	0.0168 (11)	0.0054 (9)	−0.0043 (9)
OW3	0.0596 (13)	0.0426 (11)	0.0283 (10)	0.0052 (10)	0.0113 (10)	0.0034 (8)
OW4	0.0378 (11)	0.0574 (13)	0.0401 (12)	0.0110 (10)	0.0035 (9)	−0.0020 (10)
OW5	0.0587 (14)	0.0404 (11)	0.0404 (12)	0.0139 (10)	0.0035 (10)	−0.0053 (9)
S1	0.0363 (4)	0.0360 (4)	0.0215 (3)	0.0049 (3)	0.0057 (3)	0.0032 (2)
Co1	0.0406 (3)	0.0366 (3)	0.0215 (3)	0.0113 (2)	0.0086 (2)	0.00142 (19)

Geometric parameters (Å, º)

C1—C2	1.386 (3)	O6—H6A	0.820
C1—C6	1.394 (4)	OW1—Co1	2.051 (2)
C1—S1	1.764 (3)	OW1—H1A	0.898 (18)
C2—C3	1.391 (4)	OW1—H1B	0.872 (18)
C2—H2	0.930	OW2—Co1	2.113 (2)
C3—C4	1.394 (4)	OW2—H2A	0.892 (18)
C3—C7	1.485 (3)	OW2—H2B	0.885 (18)
C4—O6	1.349 (3)	OW3—Co1	2.085 (2)
C4—C5	1.395 (4)	OW3—H3A	0.909 (18)
C5—C6	1.378 (4)	OW3—H3B	0.916 (18)
C5—H5	0.930	OW4—H4A	0.893 (18)
C6—H6	0.930	OW4—H4B	0.903 (18)
C7—O5	1.226 (3)	OW5—H5A	0.868 (18)
C7—O4	1.301 (3)	OW5—H5B	0.879 (18)
O1—S1	1.459 (2)	Co1—OW1^i	2.051 (2)
O2—S1	1.459 (2)	Co1—OW3^i	2.085 (2)
O3—S1	1.439 (2)	Co1—OW2^i	2.113 (2)
O4—H4	0.820
C2—C1—C6	119.8 (2)	H2A—OW2—H2B	101 (3)
C2—C1—S1	119.07 (19)	Co1—OW3—H3A	113 (2)
C6—C1—S1	121.0 (2)	Co1—OW3—H3B	119 (2)
C1—C2—C3	120.2 (2)	H3A—OW3—H3B	102 (3)
C1—C2—H2	119.9	H4A—OW4—H4B	113 (3)
C3—C2—H2	119.9	H5A—OW5—H5B	105 (3)
C2—C3—C4	119.9 (2)	O3—S1—O1	113.39 (15)
C2—C3—C7	119.9 (2)	O3—S1—O2	112.25 (13)
C4—C3—C7	120.2 (2)	O1—S1—O2	109.67 (14)
O6—C4—C3	122.7 (2)	O3—S1—C1	107.73 (13)
O6—C4—C5	117.7 (2)	O1—S1—C1	106.42 (13)
C3—C4—C5	119.6 (2)	O2—S1—C1	107.00 (12)
C6—C5—C4	120.3 (2)	OW1^i—Co1—OW1	180.0
C6—C5—H5	119.9	OW1^i—Co1—OW3^i	89.27 (10)
C4—C5—H5	119.9	OW1—Co1—OW3^i	90.73 (10)
C5—C6—C1	120.2 (3)	OW1^i—Co1—OW3	90.73 (10)
C5—C6—H6	119.9	OW1—Co1—OW3	89.27 (10)
C1—C6—H6	119.9	OW3^i—Co1—OW3	180.0
O5—C7—O4	123.7 (3)	OW1^i—Co1—OW2	91.54 (9)
O5—C7—C3	123.2 (2)	OW1—Co1—OW2	88.46 (9)
O4—C7—C3	113.2 (2)	OW3^i—Co1—OW2	89.29 (9)
C7—O4—H4	109.5	OW3—Co1—OW2	90.71 (9)
C4—O6—H6A	109.5	OW1^i—Co1—OW2^i	88.46 (9)
Co1—OW1—H1A	134 (2)	OW1—Co1—OW2^i	91.54 (9)
Co1—OW1—H1B	122 (2)	OW3^i—Co1—OW2^i	90.71 (9)
H1A—OW1—H1B	104 (3)	OW3—Co1—OW2^i	89.29 (9)
Co1—OW2—H2A	116 (2)	OW2—Co1—OW2^i	180.0
Co1—OW2—H2B	126 (2)
C6—C1—C2—C3	0.3 (4)	S1—C1—C6—C5	177.3 (2)
S1—C1—C2—C3	−177.55 (18)	C2—C3—C7—O5	−179.8 (3)
C1—C2—C3—C4	0.9 (4)	C4—C3—C7—O5	−1.0 (4)
C1—C2—C3—C7	179.7 (2)	C2—C3—C7—O4	0.4 (3)
C2—C3—C4—O6	177.5 (2)	C4—C3—C7—O4	179.2 (2)
C7—C3—C4—O6	−1.3 (4)	C2—C1—S1—O3	−169.6 (2)
C2—C3—C4—C5	−1.9 (4)	C6—C1—S1—O3	12.6 (3)
C7—C3—C4—C5	179.3 (2)	C2—C1—S1—O1	68.5 (2)
O6—C4—C5—C6	−177.8 (2)	C6—C1—S1—O1	−109.4 (2)
C3—C4—C5—C6	1.7 (4)	C2—C1—S1—O2	−48.7 (2)
C4—C5—C6—C1	−0.4 (4)	C6—C1—S1—O2	133.4 (2)
C2—C1—C6—C5	−0.6 (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	0.90 (2)	2.00 (2)	2.823 (3)	151 (3)
OW1—H1B···OW5^iii	0.87 (2)	1.92 (2)	2.780 (3)	170 (3)
OW2—H2B···O5^i	0.89 (2)	2.11 (2)	2.941 (3)	155 (3)
OW2—H2A···OW5^iv	0.89 (2)	1.87 (2)	2.759 (3)	173 (3)
OW3—H3A···OW4^v	0.91 (2)	1.87 (2)	2.776 (3)	172 (3)
OW3—H3B···O3^iii	0.92 (2)	1.98 (2)	2.886 (3)	171 (3)
OW4—H4A···O3	0.89 (2)	1.99 (2)	2.847 (3)	160 (3)
OW4—H4B···O1^vi	0.90 (2)	1.96 (2)	2.862 (3)	174 (3)
OW5—H5A···O2^vii	0.87 (2)	1.91 (2)	2.735 (3)	158 (3)
OW5—H5B···O1	0.88 (2)	1.96 (2)	2.791 (3)	157 (3)
O4—H4···O2^viii	0.82	1.88	2.652 (3)	156
O6—H6A···O5	0.82	1.91	2.633 (3)	146

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