Crystal structures of two new divalent transition-metal salts of carb-oxy-benzene-sulfonate anions.

Hexa-aqua-nickel(II) bis-(3-carb-oxy-4-hy-droxy-benzene-sulfonate) dihydrate, [Ni(H2O)6][C6H3(CO2H)(OH)SO3]2·2H2O, (I), crystallizes in the triclinic space group P with the nickel(II) aqua complexes on centers of inversion. The carboxyl-ate group is protonated and neither it nor the sulfonate group is involved in direct coordination to the metal ions. The structure consists of alternating layers of inorganic cations and organic anions linked by O-H⋯O hydrogen bonds that also include non-coordinated water mol-ecules of crystallization. The first-row divalent transition-metal salts of this anion are reported as both dihydrates and tetra-hydrates, with two distinct structures for the dihydrates that are both layered but differ in the hydrogen-bonding pattern. Compound (I) represents the second known example of one of these structures. Hexa-aqua-cobalt(II) bis-(3-carb-oxy-benzene-sulfonate) dihydrate, [Co(H2O)6][C6H4(CO2H)SO3]2·2H2O, (II), also crystallizes in triclinic P with the cobalt(II) aqua complexes on centers of inversion. The structure is also built of alternating layers of complex cations and organic anions without direct coordination to the metal by the protonated carboxyl-ate or unprotonated sulfonate groups. A robust O-H⋯O hydrogen-bonding network involving primarily the coordin-ated and non-coordinated water mol-ecules and sulfonate groups directs the packing. This is the first reported example of a divalent transition-metal salt of the 3-carb-oxy-benzene-sulfonate anion. © Bettinger et al. 2022.

Chemical context

Over the past two decades, organo­sulfonate and organo­carboxyl­ate anions have received significant attention as building blocks for metal-organic framework (MOF) structures (Dey et al., 2014 ▸; Shimizu et al., 2009 ▸; Cai, 2004 ▸). As part of a longstanding inter­est in metal organo­sulfonate and mixed organo­sulfonate/carboxyl­ate salts (Squattrito et al., 2019 ▸), we have continued this effort with studies of other arene­sulfonates with differing substitution patterns and two structures that resulted from this work are reported here.

Structural commentary

The product of the reaction of nickel nitrate hexa­hydrate and 5-sulfosalicylic acid (3-carb­oxy-4-hy­droxy­benzene­sulfonic acid) is [Ni(H2O)6](C6H3(CO2H)(OH)SO3)2·2H2O, (I). The compound crystallizes in the triclinic space group P with the asymmetric unit consisting of half a [Ni(H2O)6]2+ cation on the center of inversion, together with one 3-carb­oxy-4-hy­droxy­benzene­sulfonate anion and one non-coordinated water mol­ecule in general positions. As a result of the symmetry, the nickel ion has a very regular octa­hedral coordination of six water mol­ecules (Fig. 1 ▸), with Ni—O distances [2.038 (1), 2.050 (1), 2.053 (1) Å] that are consistent with reported values (Cotton et al., 1993 ▸), including the pattern of one shorter and two slightly longer distances. The O—Ni—O bond angles [87.97 (4)–91.94 (4)°] are within 2° of the ideal. The carboxyl­ate group is protonated and only slightly rotated out of the plane of the phenyl ring [torsion angle C2—C3—C7—O4 = 5.0 (2)°]. The location of the acidic H atom on O4 is unambiguously confirmed on the difference electron-density map and is supported by the C7—O4 [1.318 (2) Å] and C7—O5 [1.236 (2) Å] distances and the hydrogen-bonding pattern (Fig. 1 ▸, Table 1 ▸). The single unique water mol­ecule of crystallization forms four approximately linear strong O—H⋯O hydrogen bonds (Table 1 ▸), the two shown in Fig. 1 ▸ in which the water oxygen atom O4W is the acceptor from the carboxyl H4 and a coordinated water mol­ecule [H32#, symmetry code: (#) −x + 1, −y + 2, −z], and two in which the water hydrogen atoms H41 and H42 are donors to sulfonate oxygen atoms O1 and O2, respectively.

Figure 1

The mol­ecular structure of (I), showing the atom-numbering scheme. Displacement ellipsoids are shown at the 90% probability level and hydrogen atoms are shown as small spheres of arbitrary radii. Hydrogen bonds are shown as striped cylinders. Symmetry-equivalent oxygen atoms are included to show the complete coordination environment of the cation. [Symmetry code: (#) 1 − x, 2 − y, −z]

Table 1

Hydrogen-bond geometry (Å, °) for (I)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1W—H11⋯O1i	0.83 (1)	1.98 (1)	2.7895 (14)	165 (2)
O1W—H12⋯O5	0.83 (1)	1.92 (1)	2.7432 (14)	168 (2)
O2W—H22⋯O2ii	0.84 (1)	1.94 (1)	2.7802 (14)	176 (2)
O2W—H21⋯O3iii	0.83 (1)	2.02 (1)	2.8476 (14)	174 (2)
O3W—H32⋯O4W iv	0.83 (1)	1.99 (1)	2.8208 (14)	172 (2)
O3W—H31⋯O3ii	0.83 (1)	2.05 (1)	2.8790 (14)	175 (2)
O6—H6A⋯O5	0.84 (1)	1.84 (2)	2.5904 (16)	148 (2)
O4—H4⋯O4W	0.84 (1)	1.83 (1)	2.6656 (14)	171 (2)
O4W—H42⋯O2i	0.83 (1)	1.91 (1)	2.7420 (14)	178 (2)
O4W—H41⋯O1v	0.83 (1)	1.99 (1)	2.8029 (14)	165 (2)

Symmetry codes: (i) ; (ii) ; (iii) ; (iv) ; (v) .

The reaction of cobalt nitrate hexa­hydrate and sodium 3-sulfobenzoate (3-carb­oxy­benzene­sulfonate) produced crystals that have been identified as [Co(H2O)6](C6H4(CO2H)SO3)2·2H2O, (II). Like (I), this compound also crystallizes in the triclinic P space group with the cobalt cation on the inversion center and the water mol­ecules and 3-carb­oxy­benzene­sulfonate anion in general positions. The hexa­aqua­cobalt(II) ion has a similarly regular octa­hedral coordination with Co—O distances [2.047 (1), 2.092 (1), 2.111 (1) Å] and O—Co—O angles [87.56 (4)–91.15 (4)°] consistent with prior studies (Cotton et al., 1993 ▸). The carboxyl­ate group is unambiguously protonated on O4 [C7—O4 = 1.330 (2) Å vs C7—O5 = 1.213 (2) Å] and rotated slightly out of the plane of the ring [torsion angle C2—C3—C7—O4 = 4.6 (2)°]. The sulfon­ate group is rotated about 19° from its position in (I) [torsion angle O1—S1—C1—C2 = −44.42 (13)° in (II) vs −25.29 (12)° in (I)]. Presumably this difference is driven by the hydrogen-bonding patterns. The non-coordinated water mol­ecule has a different hydrogen-bonding environment (Table 2 ▸), functioning as an H-atom acceptor from two coordinated water mol­ecules (H22⋯O4W is shown in Fig. 2 ▸) and as a donor through H41 and H42 to the carboxyl­ate O5 and the third coordinated water mol­ecule (O1W), respectively. These inter­actions are somewhat longer and less linear than those seen in (I).

Table 2

Hydrogen-bond geometry (Å, °) for (II)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1W—H12⋯O2i	0.84 (1)	1.94 (1)	2.7757 (15)	170 (2)
O1W—H11⋯O1ii	0.84 (1)	1.91 (1)	2.7382 (15)	175 (2)
O3W—H32⋯O4W iii	0.84 (1)	2.04 (2)	2.7887 (16)	150 (2)
O3W—H31⋯O3i	0.84 (1)	1.95 (1)	2.7852 (16)	178 (2)
O2W—H22⋯O4W	0.83 (1)	1.92 (1)	2.7516 (16)	174 (2)
O2W—H21⋯O3	0.83 (1)	1.96 (1)	2.7925 (15)	176 (2)
O4—H4A⋯O2iv	0.84 (1)	1.86 (1)	2.6703 (15)	162 (2)
O4W—H42⋯O1W v	0.83 (1)	2.12 (1)	2.8960 (16)	158 (2)
O4W—H41⋯O5vi	0.83 (1)	2.08 (1)	2.8503 (16)	153 (2)

Symmetry codes: (i) ; (ii) ; (iii) ; (iv) ; (v) ; (vi) .

Figure 2

The mol­ecular structure of (II), showing the atom-numbering scheme. Displacement ellipsoids are shown at the 90% probability level and hydrogen atoms are shown as small spheres of arbitrary radii. Hydrogen bonds are shown as striped cylinders. Symmetry-equivalent oxygen atoms are included to show the complete coordination environment of the cation.

Supra­molecular features

The packing in (I) features layers of hexa­aqua­nickel(II) ions in the ab plane alternating with layers of 3-carb­oxy-4-hy­droxy­benzene­sulfonate anions stacking along the c-axis direction (Fig. 3 ▸). As has typically been found in related divalent transition-metal arene­sulfonate systems (Leonard et al., 1999 ▸), the anions are inter­leaved in the layer with half having the sulfonate groups directed towards the cation layer above and half towards the cation layer below. The structure also contains a non-coordinated water mol­ecule at the inter­face between the cation and anion layers. The packing is dominated by an extensive network of strong (H⋯O ca.1.8–2.0 Å) approximately linear O—H⋯O hydrogen bonds (Table 1 ▸, Fig. 3 ▸) involving the coordinated water mol­ecules, non-coordinated water mol­ecules, and sulfonate and carboxyl­ate groups. All of the water and carboxyl­ate H atoms participate in such an inter­molecular hydrogen bond, while each of the sulfonate and unprotonated carboxyl­ate O atoms function as hydrogen-bond acceptors. The hydroxyl group participates only in an intra­molecular hydrogen bond with the adjacent carboxyl­ate O atom (shown in Fig. 1 ▸).

Figure 3

Packing diagram of (I) with the outline of the unit cell. The alternating layers of hexa­aqua­nickel(II) cations and 3-carb­oxy-4-hy­droxy­benzene­sulfonate anions are evident. O—H⋯O hydrogen bonds are shown as striped cylinders. H atoms bonded to C atoms have been omitted. Displacement ellipsoids are drawn at the 90% probability level.

A hexa­aqua­nickel(II) salt of 3-carb­oxy-4-hy­droxy­benzene­sulfonate has been reported previously (Ma et al., 2003a ▸), but unlike (I) it is a tetra­hydrate with two independent non-coordinated water mol­ecules. The extended structure is layered like (I), but differs in the incorporation of the additional water, which results in a modest expansion of the unit cell along the stacking axis c and changes to the triclinic cell angles. The [M(H2O)6](C6H3(CO2H)(OH)SO3)2·4H2O structure has also been reported for cobalt (Ma et al., 2003b ▸) and zinc (Ma et al., 2003c ▸). Dihydrates of the formula [M(H2O)6](C6H3(CO2H)(OH)SO3)2·2H2O have been reported for manganese (Ma et al., 2003d ▸), cobalt (Abdelhak et al., 2005 ▸), copper (Ma et al., 2003e ▸), and zinc (Lamshöft et al., 2011 ▸). The Mn and Co compounds are isostructural, but the structure is not the same as (I). Specifically, the non-coordinated water mol­ecule is situated differently. In (I) it acts as a hydrogen-bond acceptor from the carboxyl H atom and a coordinated water mol­ecule, while acting as an H-atom donor to two sulfonate O atoms. In the reported Mn and Co dihydrates, the non-coordinated water mol­ecule is a hydrogen-bond acceptor from two coordinated water mol­ecules and an H-atom donor to the unprotonated carboxyl­ate O atom and a coordinated water mol­ecule. The copper dihydrate is superficially similar to the Mn and Co analogs, although the hexa­aqua­copper(II) cation has the expected Jahn–Teller distortion. Perhaps as a result of this, the non-coordinated water mol­ecule has yet a different hydrogen-bonding pattern, accepting from two coordinated water mol­ecules but donating to a sulfonate O atom and a coordinated water mol­ecule. Of the reported dihydrates, only the Zn analog appears to have the same structure as (I) based on the space group and unit-cell dimensions. According to the deposited CIF, only a few of the water H atoms were included in the model and only a cursory description of the extended structure is provided in the paper (Lamshöft et al., 2011 ▸). Thus, (I) represents the first complete structure determination of this dihydrate variant. A recent study of the zinc 3-carb­oxy-4-hy­droxy­benzene­sulfonate system (Song et al., 2019 ▸) demonstrates that it is possible to inter­convert the dihydrate and tetra­hydrate structures by exposure to different relative humidities at moderate temperatures (303 or 313 K). This suggests that the structures are close in energy, as are presumably the dihydrate structures.

The extended structure of (II) is similar to that of (I) with layers of hexa­aqua­cobalt(II) cations in the ab plane alternating with layers of inter­leaved 3-carb­oxy­benzene­sulfonate anions (Fig. 4 ▸). Two water mol­ecules per formula unit are found in the inter­face between the layers. The hydrogen-bonding network is somewhat different from that in (I) (Table 2 ▸). The non-coordinated water mol­ecule acts as an H-atom donor to a coordinated water mol­ecule and the unprotonated carboxyl­ate O atom (inter­actions shown in Fig. 4 ▸), and as an H-atom acceptor from the other coordinated water mol­ecules (one of which is shown in Fig. 2 ▸). Other O—H⋯O inter­actions between the coordinated water mol­ecules, the carboxyl­ate H atom, and the sulfonate O atoms complete the hydrogen-bonding scheme. This is the first reported structure of a divalent d-block transition-metal salt of 3-carb­oxy­benzene­sulfonate, so it represents a new member of the metal arene­sulfonate family of layered compounds.

Figure 4

Packing diagram of (II) with the outline of the unit cell showing the alternating layers of hexa­aqua­cobalt(II) cations and 3-carb­oxy­benzene­sulfonate anions. O—H⋯O hydrogen bonds are shown as striped cylinders. H atoms bonded to C atoms have been omitted. Displacement ellipsoids are drawn at the 90% probability level.

Database survey

A search of the Cambridge Structural Database (CSD, Version 5.42, update of November 2020; Groom et al., 2016 ▸) for the COOH-protonated 3-carb­oxy-4-hy­droxy­benzene­sulfonate ion yielded 21 hits. The ten reported structures containing only metal ions and 3-carb­oxy­benzene­sulfonate ions, with or without water mol­ecules, are tri­aqua­(3-carb­oxy-4-hy­droxy­benzene­sulfonato)­silver monohydrate (refcode FETHES; Gao et al., 2005a ▸), penta­aqua-oxo-vanadium(IV) 3-carb­oxy-4-hy­droxy­benzene­sulfonate dihydrate (refcode OBUZUH; Li et al., 2004 ▸), hexa­aqua­manganese(II) 3-carb­oxy-4-hy­droxy­benzene­sulfonate dihydrate (refcode KAGMOV; Ma et al., 2003d ▸), hexa­aqua­cobalt(II) 3-carb­oxy-4-hy­droxy­benzene­sulfonate dihydrate (refcode SAYVEU; Abdelhak et al., 2005 ▸), hexa­aqua­cobalt(II) 3-carb­oxy-4-hy­droxy­benzene­sulfonate tetra­hydrate (refcode KAGMUB; Ma et al., 2003b ▸), hexa­aqua­nickel(II) 3-carb­oxy-4-hy­droxy­benz­ene­sulfonate tetra­hydrate (refcode KAGNAI; Ma et al., 2003a ▸), hexa­aqua­copper(II) 3-carb­oxy-4-hy­droxy­benzene­sulfonate dihydrate (refcode KAGNEM; Ma et al., 2003e ▸), hexa­aqua­zinc(II) 3-carb­oxy-4-hy­droxy­benzene­sulfonate tetra­hydrate (refcode KAGNIQ; Ma et al., 2003c ▸), hexa­aqua­zinc(II) 3-carb­oxy-4-hy­droxy­benzene­sulfonate dihydrate (refcode FARFOV; Lamshöft et al., 2011 ▸), and bis­(3-carb­oxy-4-hy­droxy­benzene­sulfonato)­diaqua­zinc(II) hydrate (refcode VOJYEB; Song et al., 2019 ▸). Of these structures, only FETHES and VOJYEB feature direct bonding between the sulfonate O atoms and the metal ions, while all of the others are similar to the structures reported herein.

A search of the Cambridge Structural Database (CSD, Version 5.42, update of November 2020; Groom et al., 2016 ▸) for the COOH-protonated 3-carb­oxy­benzene­sulfonate ion yielded 15 hits. The five reported structures containing only metal ions and 3-carb­oxy­benzene­sulfonate ions, with or without water mol­ecules, are silver 3-carb­oxy­benzene­sulfonate at 293 K (refcode ROJJUW; Prochniak et al., 2008 ▸) and 100 K (refcode ROJJUW01; Bettinger et al., 2020 ▸), sodium 3-carb­oxy­benzene­sulfonate dihydrate (refcode ROJJOQ; Prochniak et al., 2008 ▸), bis­muth(III) 3-carb­oxy­benzene­sulfonate tetra­hydrate (refcode LEXKAD; Senevirathna et al., 2018 ▸), and barium 3-carb­oxy­benzene­sulfonate trihydrate (refcode FOBXUQ; Gao et al., 2005b ▸). All of these structures feature direct bonding between the sulfonate O atoms and the metal ions with resulting frameworks of varying dimensionalities.

Synthesis and crystallization

A 2.54 g (10.0 mmol) sample of 5-sulfosalicylic acid (3-carb­oxy-4-hy­droxy­benzene­sulfonic acid) (EMD Chemicals, >99%) was dissolved in 100 ml of water. To this colorless solution was added a green solution of 2.91 g (10.0 mmol) of Ni(NO3)2 .6H2O (Aldrich) in 50 ml of water. The resulting clear green solution was stirred for about 30 minutes and transferred to a porcelain evaporating dish that was set out to evaporate in a fume hood. After several days, the water had completely evaporated leaving behind large elongated (>1 cm) green slab-shaped crystals, 2.57 g of which were collected by hand from the dish. These were identified as (I) through the single-crystal X-ray study. A 2.24 g (10.0 mmol) sample of sodium 3-sulfobenzoate (Aldrich, 97%) was dissolved in 45 ml of water. To this colorless solution was added a red solution of 2.91 g (10.0 mmol) of Co(NO3)2 .6H2O (Aldrich) in 50 ml of water. The resulting red solution was stirred for 30 minutes, transferred to a porcelain dish, and set out to evaporate. The final red product was primarily polycrystalline but some small red–pink plates were found to be suitable for single-crystal X-ray analysis, leading to their identification as (II).

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 3 ▸. Hydrogen atoms bonded to carbon atoms were located in difference electron-density maps, constrained on idealized positions, and included in the refinement as riding atoms with C—H = 0.95 Å and their U iso constrained to be 1.2 times the U eq of the bonding atom. Oxygen-bound hydrogen atoms were located in difference electron-density maps and refined with isotropic displacement parameters while the O—H distances were restrained to 0.84 (1) Å.

Table 3

Experimental details

	(I)	(II)
Crystal data
Chemical formula	[Ni(H2O)6](C7H5O6S)2·2H2O	[Co(H2O)6](C7H5O5S)2·2H2O
M r	637.18	605.40
Crystal system, space group	Triclinic, P	Triclinic, P
Temperature (K)	150	150
a, b, c (Å)	6.5986 (7), 7.4183 (8), 13.2847 (14)	6.7774 (11), 6.9866 (11), 13.721 (2)
α, β, γ (°)	74.1712 (14), 88.6035 (14), 77.9200 (13)	91.107 (2), 90.401 (2), 117.5832 (19)
V (Å3)	611.41 (11)	575.66 (16)
Z	1	1
Radiation type	Mo Kα	Mo Kα
μ (mm−1)	1.06	1.01
Crystal size (mm)	0.22 × 0.16 × 0.10	0.30 × 0.14 × 0.08
Data collection
Diffractometer	Bruker Duo with APEXII CCD	Bruker Duo with APEXII CCD
Absorption correction	Multi-scan (SADABS; Krause et al., 2015 ▸)	Multi-scan (SADABS; Krause et al., 2015 ▸)
T min, T max	0.670, 0.746	0.688, 0.746
No. of measured, independent and observed [I > 2σ(I)] reflections	8656, 3047, 2779	8197, 2881, 2578
R int	0.019	0.020
(sin θ/λ)max (Å−1)	0.669	0.669
Refinement
R[F 2 > 2σ(F 2)], wR(F 2), S	0.023, 0.059, 1.08	0.024, 0.062, 1.05
No. of reflections	3047	2881
No. of parameters	209	196
No. of restraints	10	9
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement	H atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å−3)	0.33, −0.41	0.41, −0.43

Computer programs: APEX3 and SAINT (Bruker, 2015 ▸), SHELXT2014/5 (Sheldrick, 2015a ▸), SHELXL2018/3 (Sheldrick, 2015b ▸), and CrystalMaker (Palmer, 2014 ▸).

Crystal structure: contains datablock(s) I, II, global. DOI: 10.1107/S2056989022008295/mw2190sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S2056989022008295/mw2190Isup2.hkl

Structure factors: contains datablock(s) II. DOI: 10.1107/S2056989022008295/mw2190IIsup3.hkl

CCDC references: 2202460, 2202459

Additional supporting information: crystallographic information; 3D view; checkCIF report

[Ni(H2O)6](C7H5O6S)2·2H2O	Z = 1
Mr = 637.18	F(000) = 330
Triclinic, P1	Dx = 1.731 Mg m−3
a = 6.5986 (7) Å	Mo Kα radiation, λ = 0.71073 Å
b = 7.4183 (8) Å	Cell parameters from 4943 reflections
c = 13.2847 (14) Å	θ = 2.9–28.3°
α = 74.1712 (14)°	µ = 1.06 mm−1
β = 88.6035 (14)°	T = 150 K
γ = 77.9200 (13)°	Block, green
V = 611.41 (11) Å3	0.22 × 0.16 × 0.10 mm

Bruker Duo with APEXII CCD diffractometer	2779 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.019
ω scans	θmax = 28.4°, θmin = 2.9°
Absorption correction: multi-scan (SADABS; Krause et al., 2015)	h = −8→8
Tmin = 0.670, Tmax = 0.746	k = −9→9
8656 measured reflections	l = −17→17
3047 independent reflections

Refinement on F2	Primary atom site location: dual
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.023	Hydrogen site location: difference Fourier map
wR(F2) = 0.059	H atoms treated by a mixture of independent and constrained refinement
S = 1.08	w = 1/[σ2(Fo2) + (0.0284P)2 + 0.2223P] where P = (Fo2 + 2Fc2)/3
3047 reflections	(Δ/σ)max < 0.001
209 parameters	Δρmax = 0.33 e Å−3
10 restraints	Δρmin = −0.41 e Å−3

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.

	x	y	z	Uiso*/Ueq
Ni1	0.500000	1.000000	0.000000	0.01105 (7)
O1W	0.40237 (15)	0.99422 (14)	0.14733 (7)	0.0161 (2)
H11	0.342 (3)	1.095 (2)	0.1600 (16)	0.039 (6)*
H12	0.488 (3)	0.939 (3)	0.1966 (12)	0.041 (6)*
O2W	0.66270 (15)	0.72230 (14)	0.05040 (8)	0.0171 (2)
H22	0.596 (3)	0.642 (3)	0.0846 (16)	0.048 (6)*
H21	0.7789 (19)	0.701 (3)	0.0795 (15)	0.037 (6)*
O3W	0.23500 (15)	0.91381 (15)	−0.02663 (8)	0.0168 (2)
H32	0.220 (3)	0.884 (3)	−0.0816 (11)	0.037 (6)*
H31	0.182 (3)	0.840 (2)	0.0200 (12)	0.033 (5)*
S1	0.78200 (5)	0.52327 (5)	0.79824 (2)	0.01278 (8)
O1	0.84194 (15)	0.70694 (14)	0.78658 (8)	0.0177 (2)
O2	0.56747 (14)	0.52970 (14)	0.83170 (8)	0.0176 (2)
O3	0.92577 (15)	0.35961 (14)	0.86440 (8)	0.0181 (2)
O6	0.73062 (17)	0.39614 (16)	0.38141 (8)	0.0211 (2)
H6A	0.704 (4)	0.503 (2)	0.3355 (14)	0.051 (7)*
O5	0.68377 (16)	0.76283 (15)	0.30157 (8)	0.0204 (2)
O4	0.72336 (17)	0.94807 (15)	0.40456 (8)	0.0213 (2)
H4	0.727 (3)	1.025 (3)	0.3454 (10)	0.042 (6)*
C1	0.78448 (19)	0.48905 (19)	0.67154 (10)	0.0135 (2)
C6	0.8006 (2)	0.30381 (19)	0.66125 (11)	0.0159 (3)
H6	0.823672	0.197124	0.721651	0.019*
C5	0.7830 (2)	0.2757 (2)	0.56350 (11)	0.0171 (3)
H5	0.793317	0.149826	0.556807	0.021*
C4	0.7498 (2)	0.4327 (2)	0.47420 (11)	0.0159 (3)
C3	0.7387 (2)	0.61877 (19)	0.48438 (10)	0.0141 (3)
C7	0.7129 (2)	0.7820 (2)	0.38932 (11)	0.0160 (3)
C2	0.7559 (2)	0.64496 (19)	0.58405 (10)	0.0140 (2)
H2	0.747996	0.769976	0.591539	0.017*
O4W	0.77781 (16)	1.17956 (14)	0.21815 (8)	0.0167 (2)
H42	0.674 (2)	1.269 (2)	0.2040 (16)	0.035 (6)*
H41	0.879 (2)	1.230 (3)	0.2199 (17)	0.039 (6)*

	U11	U22	U33	U12	U13	U23
Ni1	0.01121 (12)	0.01190 (12)	0.00927 (12)	−0.00301 (8)	−0.00053 (8)	−0.00113 (8)
O1W	0.0184 (5)	0.0172 (5)	0.0110 (4)	−0.0021 (4)	−0.0004 (4)	−0.0025 (4)
O2W	0.0140 (5)	0.0145 (5)	0.0199 (5)	−0.0035 (4)	−0.0020 (4)	0.0005 (4)
O3W	0.0168 (5)	0.0226 (5)	0.0129 (5)	−0.0095 (4)	0.0003 (4)	−0.0043 (4)
S1	0.01103 (15)	0.01454 (16)	0.01148 (15)	−0.00312 (11)	0.00037 (11)	−0.00112 (12)
O1	0.0193 (5)	0.0183 (5)	0.0175 (5)	−0.0079 (4)	0.0035 (4)	−0.0054 (4)
O2	0.0122 (4)	0.0205 (5)	0.0172 (5)	−0.0030 (4)	0.0032 (4)	−0.0009 (4)
O3	0.0150 (5)	0.0208 (5)	0.0147 (5)	−0.0010 (4)	−0.0024 (4)	0.0001 (4)
O6	0.0239 (5)	0.0249 (6)	0.0174 (5)	−0.0068 (4)	−0.0005 (4)	−0.0093 (4)
O5	0.0211 (5)	0.0251 (5)	0.0132 (5)	−0.0040 (4)	−0.0028 (4)	−0.0024 (4)
O4	0.0306 (6)	0.0159 (5)	0.0142 (5)	−0.0040 (4)	−0.0003 (4)	0.0007 (4)
C1	0.0103 (6)	0.0161 (6)	0.0132 (6)	−0.0030 (5)	−0.0002 (4)	−0.0021 (5)
C6	0.0130 (6)	0.0153 (6)	0.0174 (6)	−0.0038 (5)	0.0008 (5)	−0.0005 (5)
C5	0.0157 (6)	0.0154 (6)	0.0215 (7)	−0.0050 (5)	0.0015 (5)	−0.0058 (5)
C4	0.0101 (6)	0.0219 (7)	0.0166 (6)	−0.0042 (5)	0.0004 (5)	−0.0062 (5)
C3	0.0104 (6)	0.0169 (6)	0.0134 (6)	−0.0027 (5)	0.0002 (5)	−0.0015 (5)
C7	0.0112 (6)	0.0192 (7)	0.0149 (6)	−0.0012 (5)	0.0001 (5)	−0.0014 (5)
C2	0.0124 (6)	0.0141 (6)	0.0145 (6)	−0.0029 (5)	0.0004 (5)	−0.0024 (5)
O4W	0.0160 (5)	0.0164 (5)	0.0178 (5)	−0.0044 (4)	−0.0009 (4)	−0.0039 (4)

Ni1—O1Wi	2.0376 (10)	O6—H6A	0.843 (10)
Ni1—O1W	2.0376 (10)	O5—C7	1.2364 (17)
Ni1—O2Wi	2.0498 (10)	O4—C7	1.3179 (18)
Ni1—O2W	2.0498 (10)	O4—H4	0.839 (9)
Ni1—O3W	2.0526 (10)	C1—C2	1.3821 (18)
Ni1—O3Wi	2.0526 (10)	C1—C6	1.3996 (19)
O1W—H11	0.829 (9)	C6—C5	1.3816 (19)
O1W—H12	0.832 (10)	C6—H6	0.9500
O2W—H22	0.838 (10)	C5—C4	1.4016 (19)
O2W—H21	0.832 (9)	C5—H5	0.9500
O3W—H32	0.833 (9)	C4—C3	1.4098 (19)
O3W—H31	0.831 (9)	C3—C2	1.4003 (18)
S1—O3	1.4570 (10)	C3—C7	1.4762 (19)
S1—O1	1.4644 (10)	C2—H2	0.9500
S1—O2	1.4685 (10)	O4W—H42	0.832 (9)
S1—C1	1.7685 (14)	O4W—H41	0.834 (10)
O6—C4	1.3466 (17)
O1Wi—Ni1—O1W	180.0	O3—S1—C1	106.97 (6)
O1Wi—Ni1—O2Wi	91.26 (4)	O1—S1—C1	106.29 (6)
O1W—Ni1—O2Wi	88.74 (4)	O2—S1—C1	105.69 (6)
O1Wi—Ni1—O2W	88.74 (4)	C4—O6—H6A	107.2 (16)
O1W—Ni1—O2W	91.26 (4)	C7—O4—H4	107.2 (15)
O2Wi—Ni1—O2W	180.0	C2—C1—C6	120.45 (12)
O1Wi—Ni1—O3W	92.03 (4)	C2—C1—S1	120.22 (10)
O1W—Ni1—O3W	87.97 (4)	C6—C1—S1	119.17 (10)
O2Wi—Ni1—O3W	88.06 (4)	C5—C6—C1	120.19 (12)
O2W—Ni1—O3W	91.94 (4)	C5—C6—H6	119.9
O1Wi—Ni1—O3Wi	87.97 (4)	C1—C6—H6	119.9
O1W—Ni1—O3Wi	92.03 (4)	C6—C5—C4	120.03 (13)
O2Wi—Ni1—O3Wi	91.94 (4)	C6—C5—H5	120.0
O2W—Ni1—O3Wi	88.06 (4)	C4—C5—H5	120.0
O3W—Ni1—O3Wi	180.0	O6—C4—C5	117.16 (13)
Ni1—O1W—H11	119.4 (15)	O6—C4—C3	123.10 (12)
Ni1—O1W—H12	117.2 (15)	C5—C4—C3	119.74 (12)
H11—O1W—H12	106 (2)	C2—C3—C4	119.51 (12)
Ni1—O2W—H22	116.1 (16)	C2—C3—C7	121.27 (12)
Ni1—O2W—H21	118.9 (15)	C4—C3—C7	119.21 (12)
H22—O2W—H21	109 (2)	O5—C7—O4	122.61 (13)
Ni1—O3W—H32	119.8 (15)	O5—C7—C3	121.89 (13)
Ni1—O3W—H31	122.3 (14)	O4—C7—C3	115.49 (12)
H32—O3W—H31	106 (2)	C1—C2—C3	120.05 (12)
O3—S1—O1	113.84 (6)	C1—C2—H2	120.0
O3—S1—O2	111.87 (6)	C3—C2—H2	120.0
O1—S1—O2	111.57 (6)	H42—O4W—H41	106 (2)
O3—S1—C1—C2	−147.25 (11)	C5—C4—C3—C2	−1.56 (19)
O1—S1—C1—C2	−25.29 (12)	O6—C4—C3—C7	−2.41 (19)
O2—S1—C1—C2	93.39 (11)	C5—C4—C3—C7	177.36 (12)
O3—S1—C1—C6	37.34 (12)	C2—C3—C7—O5	−175.12 (12)
O1—S1—C1—C6	159.30 (10)	C4—C3—C7—O5	5.97 (19)
O2—S1—C1—C6	−82.02 (11)	C2—C3—C7—O4	5.01 (18)
C2—C1—C6—C5	−1.6 (2)	C4—C3—C7—O4	−173.89 (12)
S1—C1—C6—C5	173.82 (10)	C6—C1—C2—C3	1.29 (19)
C1—C6—C5—C4	0.3 (2)	S1—C1—C2—C3	−174.06 (10)
C6—C5—C4—O6	−178.94 (12)	C4—C3—C2—C1	0.28 (19)
C6—C5—C4—C3	1.3 (2)	C7—C3—C2—C1	−178.62 (12)
O6—C4—C3—C2	178.67 (12)

D—H···A	D—H	H···A	D···A	D—H···A
O1W—H11···O1ii	0.83 (1)	1.98 (1)	2.7895 (14)	165 (2)
O1W—H12···O5	0.83 (1)	1.92 (1)	2.7432 (14)	168 (2)
O2W—H22···O2iii	0.84 (1)	1.94 (1)	2.7802 (14)	176 (2)
O2W—H21···O3iv	0.83 (1)	2.02 (1)	2.8476 (14)	174 (2)
O3W—H32···O4Wi	0.83 (1)	1.99 (1)	2.8208 (14)	172 (2)
O3W—H31···O3iii	0.83 (1)	2.05 (1)	2.8790 (14)	175 (2)
O6—H6A···O5	0.84 (1)	1.84 (2)	2.5904 (16)	148 (2)
O4—H4···O4W	0.84 (1)	1.83 (1)	2.6656 (14)	171 (2)
O4W—H42···O2ii	0.83 (1)	1.91 (1)	2.7420 (14)	178 (2)
O4W—H41···O1v	0.83 (1)	1.99 (1)	2.8029 (14)	165 (2)

[Co(H2O)6](C7H5O5S)2·2H2O	Z = 1
Mr = 605.40	F(000) = 313
Triclinic, P1	Dx = 1.746 Mg m−3
a = 6.7774 (11) Å	Mo Kα radiation, λ = 0.71073 Å
b = 6.9866 (11) Å	Cell parameters from 4422 reflections
c = 13.721 (2) Å	θ = 3.0–28.3°
α = 91.107 (2)°	µ = 1.01 mm−1
β = 90.401 (2)°	T = 150 K
γ = 117.5832 (19)°	Plate, red-pink
V = 575.66 (16) Å3	0.30 × 0.14 × 0.08 mm

Bruker Duo with APEXII CCD diffractometer	2578 reflections with I > 2σ(I)
Radiation source: fine focus sealed tube	Rint = 0.020
ω scans	θmax = 28.4°, θmin = 3.0°
Absorption correction: multi-scan (SADABS; Krause et al., 2015)	h = −9→9
Tmin = 0.688, Tmax = 0.746	k = −9→9
8197 measured reflections	l = −18→18
2881 independent reflections

Refinement on F2	Primary atom site location: dual
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.024	Hydrogen site location: difference Fourier map
wR(F2) = 0.062	H atoms treated by a mixture of independent and constrained refinement
S = 1.05	w = 1/[σ2(Fo2) + (0.030P)2 + 0.2552P] where P = (Fo2 + 2Fc2)/3
2881 reflections	(Δ/σ)max < 0.001
196 parameters	Δρmax = 0.41 e Å−3
9 restraints	Δρmin = −0.43 e Å−3

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.

	x	y	z	Uiso*/Ueq
Co1	0.500000	0.500000	0.000000	0.01139 (8)
O1W	0.59207 (18)	0.45162 (17)	0.14109 (8)	0.0168 (2)
H12	0.490 (3)	0.376 (3)	0.1797 (14)	0.049 (7)*
H11	0.691 (3)	0.558 (2)	0.1710 (14)	0.033 (6)*
O3W	0.3051 (2)	0.16486 (17)	−0.01333 (8)	0.0224 (2)
H32	0.273 (4)	0.088 (3)	−0.0641 (12)	0.051 (7)*
H31	0.290 (4)	0.086 (3)	0.0345 (11)	0.035 (6)*
O2W	0.22949 (19)	0.52152 (18)	0.05338 (8)	0.0205 (2)
H22	0.113 (3)	0.421 (3)	0.0736 (17)	0.051 (7)*
H21	0.239 (4)	0.632 (2)	0.0817 (15)	0.040 (6)*
S1	0.15442 (6)	0.93233 (5)	0.23000 (2)	0.01271 (8)
O1	−0.08728 (17)	0.81710 (17)	0.23196 (8)	0.0193 (2)
O3	0.25157 (19)	0.89453 (17)	0.14174 (7)	0.0200 (2)
O4	−0.04855 (19)	0.77393 (18)	0.59079 (8)	0.0204 (2)
H4A	−0.102 (4)	0.773 (4)	0.6461 (10)	0.049 (7)*
O5	0.19717 (19)	0.69905 (18)	0.67033 (8)	0.0230 (2)
O2	0.23686 (17)	1.16534 (16)	0.24926 (7)	0.0157 (2)
C2	0.1502 (2)	0.8151 (2)	0.41772 (10)	0.0135 (3)
H2	0.026154	0.842780	0.423772	0.016*
C5	0.5099 (2)	0.7283 (2)	0.39875 (11)	0.0183 (3)
H5	0.631065	0.696301	0.392134	0.022*
C6	0.4323 (2)	0.7927 (2)	0.31792 (11)	0.0165 (3)
H6	0.500627	0.806287	0.256469	0.020*
C3	0.2302 (2)	0.7524 (2)	0.49829 (10)	0.0138 (3)
C7	0.1271 (2)	0.7374 (2)	0.59558 (10)	0.0156 (3)
C1	0.2530 (2)	0.8369 (2)	0.32839 (10)	0.0132 (3)
C4	0.4119 (2)	0.7104 (2)	0.48891 (11)	0.0171 (3)
H4	0.468088	0.669793	0.544051	0.020*
O4W	−0.15844 (19)	0.20955 (18)	0.12941 (8)	0.0191 (2)
H42	−0.242 (3)	0.263 (3)	0.1173 (16)	0.037 (6)*
H41	−0.145 (4)	0.214 (4)	0.1900 (7)	0.045 (7)*

	U11	U22	U33	U12	U13	U23
Co1	0.01209 (13)	0.01120 (13)	0.01100 (13)	0.00549 (10)	0.00119 (9)	0.00036 (9)
O1W	0.0156 (5)	0.0169 (5)	0.0132 (5)	0.0035 (4)	0.0007 (4)	0.0009 (4)
O3W	0.0337 (6)	0.0126 (5)	0.0138 (5)	0.0046 (5)	0.0004 (5)	0.0003 (4)
O2W	0.0180 (5)	0.0178 (5)	0.0261 (6)	0.0086 (5)	0.0071 (4)	−0.0011 (5)
S1	0.01491 (17)	0.01270 (16)	0.01041 (16)	0.00627 (13)	0.00180 (12)	0.00044 (12)
O1	0.0148 (5)	0.0194 (5)	0.0195 (5)	0.0046 (4)	−0.0025 (4)	0.0004 (4)
O3	0.0318 (6)	0.0214 (5)	0.0121 (5)	0.0167 (5)	0.0064 (4)	0.0020 (4)
O4	0.0242 (6)	0.0270 (6)	0.0142 (5)	0.0153 (5)	0.0057 (4)	0.0015 (4)
O5	0.0289 (6)	0.0270 (6)	0.0138 (5)	0.0135 (5)	0.0004 (4)	0.0033 (4)
O2	0.0182 (5)	0.0132 (5)	0.0157 (5)	0.0072 (4)	0.0040 (4)	0.0011 (4)
C2	0.0129 (6)	0.0123 (6)	0.0144 (7)	0.0052 (5)	0.0017 (5)	−0.0002 (5)
C5	0.0150 (7)	0.0176 (7)	0.0244 (8)	0.0093 (6)	0.0029 (6)	0.0021 (6)
C6	0.0160 (7)	0.0151 (7)	0.0177 (7)	0.0067 (6)	0.0044 (5)	0.0015 (5)
C3	0.0162 (7)	0.0107 (6)	0.0128 (6)	0.0048 (5)	0.0018 (5)	0.0004 (5)
C7	0.0184 (7)	0.0102 (6)	0.0156 (7)	0.0046 (5)	0.0010 (5)	0.0000 (5)
C1	0.0140 (6)	0.0113 (6)	0.0129 (6)	0.0047 (5)	0.0010 (5)	0.0002 (5)
C4	0.0178 (7)	0.0140 (7)	0.0194 (7)	0.0073 (6)	−0.0014 (5)	0.0022 (5)
O4W	0.0223 (6)	0.0231 (5)	0.0152 (5)	0.0134 (5)	−0.0012 (4)	−0.0005 (4)

Co1—O2W	2.0470 (11)	O4—C7	1.3298 (18)
Co1—O2Wi	2.0470 (11)	O4—H4A	0.841 (10)
Co1—O3W	2.0921 (11)	O5—C7	1.2126 (18)
Co1—O3Wi	2.0921 (11)	C2—C1	1.3898 (19)
Co1—O1W	2.1107 (11)	C2—C3	1.3921 (19)
Co1—O1Wi	2.1107 (11)	C2—H2	0.9500
O1W—H12	0.844 (10)	C5—C4	1.389 (2)
O1W—H11	0.835 (9)	C5—C6	1.393 (2)
O3W—H32	0.836 (10)	C5—H5	0.9500
O3W—H31	0.839 (9)	C6—C1	1.393 (2)
O2W—H22	0.832 (10)	C6—H6	0.9500
O2W—H21	0.830 (10)	C3—C4	1.398 (2)
S1—O1	1.4534 (11)	C3—C7	1.494 (2)
S1—O3	1.4594 (11)	C4—H4	0.9500
S1—O2	1.4735 (10)	O4W—H42	0.827 (10)
S1—C1	1.7742 (14)	O4W—H41	0.834 (10)
O2W—Co1—O2Wi	180.0	O1—S1—C1	106.70 (7)
O2W—Co1—O3W	88.95 (5)	O3—S1—C1	106.69 (7)
O2Wi—Co1—O3W	91.05 (5)	O2—S1—C1	106.26 (6)
O2W—Co1—O3Wi	91.05 (5)	C7—O4—H4A	112.1 (17)
O2Wi—Co1—O3Wi	88.95 (5)	C1—C2—C3	119.60 (13)
O3W—Co1—O3Wi	180.0	C1—C2—H2	120.2
O2W—Co1—O1W	91.15 (4)	C3—C2—H2	120.2
O2Wi—Co1—O1W	88.85 (4)	C4—C5—C6	120.60 (13)
O3W—Co1—O1W	87.56 (4)	C4—C5—H5	119.7
O3Wi—Co1—O1W	92.44 (4)	C6—C5—H5	119.7
O2W—Co1—O1Wi	88.85 (4)	C5—C6—C1	119.12 (13)
O2Wi—Co1—O1Wi	91.15 (4)	C5—C6—H6	120.4
O3W—Co1—O1Wi	92.44 (4)	C1—C6—H6	120.4
O3Wi—Co1—O1Wi	87.56 (4)	C2—C3—C4	120.01 (13)
O1W—Co1—O1Wi	180.0	C2—C3—C7	120.06 (13)
Co1—O1W—H12	118.4 (17)	C4—C3—C7	119.90 (13)
Co1—O1W—H11	117.6 (15)	O5—C7—O4	123.99 (14)
H12—O1W—H11	110 (2)	O5—C7—C3	123.95 (14)
Co1—O3W—H32	127.8 (18)	O4—C7—C3	112.06 (12)
Co1—O3W—H31	120.3 (15)	C2—C1—C6	120.86 (13)
H32—O3W—H31	108 (2)	C2—C1—S1	117.65 (11)
Co1—O2W—H22	127.0 (17)	C6—C1—S1	121.45 (11)
Co1—O2W—H21	122.7 (16)	C5—C4—C3	119.79 (13)
H22—O2W—H21	105 (2)	C5—C4—H4	120.1
O1—S1—O3	114.70 (7)	C3—C4—H4	120.1
O1—S1—O2	111.06 (6)	H42—O4W—H41	106 (2)
O3—S1—O2	110.90 (6)
C4—C5—C6—C1	−0.7 (2)	C5—C6—C1—S1	176.87 (11)
C1—C2—C3—C4	−0.4 (2)	O1—S1—C1—C2	−44.42 (13)
C1—C2—C3—C7	177.42 (12)	O3—S1—C1—C2	−167.47 (11)
C2—C3—C7—O5	−174.55 (14)	O2—S1—C1—C2	74.15 (12)
C4—C3—C7—O5	3.3 (2)	O1—S1—C1—C6	137.89 (12)
C2—C3—C7—O4	4.61 (19)	O3—S1—C1—C6	14.84 (14)
C4—C3—C7—O4	−177.56 (13)	O2—S1—C1—C6	−103.54 (12)
C3—C2—C1—C6	1.3 (2)	C6—C5—C4—C3	1.5 (2)
C3—C2—C1—S1	−176.42 (10)	C2—C3—C4—C5	−1.0 (2)
C5—C6—C1—C2	−0.7 (2)	C7—C3—C4—C5	−178.82 (13)

D—H···A	D—H	H···A	D···A	D—H···A
O1W—H12···O2ii	0.84 (1)	1.94 (1)	2.7757 (15)	170 (2)
O1W—H11···O1iii	0.84 (1)	1.91 (1)	2.7382 (15)	175 (2)
O3W—H32···O4Wiv	0.84 (1)	2.04 (2)	2.7887 (16)	150 (2)
O3W—H31···O3ii	0.84 (1)	1.95 (1)	2.7852 (16)	178 (2)
O2W—H22···O4W	0.83 (1)	1.92 (1)	2.7516 (16)	174 (2)
O2W—H21···O3	0.83 (1)	1.96 (1)	2.7925 (15)	176 (2)
O4—H4A···O2v	0.84 (1)	1.86 (1)	2.6703 (15)	162 (2)
O4W—H42···O1Wvi	0.83 (1)	2.12 (1)	2.8960 (16)	158 (2)
O4W—H41···O5vii	0.83 (1)	2.08 (1)	2.8503 (16)	153 (2)