Hexaaqua­magnesium bis­(3-carb­oxy-4-hy­droxy­benzene­sulfonate) dihydrate

Graham Smith; Urs D Wermuth; Michael L Williams

doi:10.1107/S1600536811030777

. 2011 Aug 6;67(Pt 9):m1194. doi: 10.1107/S1600536811030777

Hexaaquamagnesium bis(3-carboxy-4-hydroxybenzenesulfonate) dihydrate

Graham Smith ^a,^*, Urs D Wermuth ^a, Michael L Williams ^b

PMCID: PMC3200685 PMID: 22065818

Abstract

In the crystal structure of the title compound, [Mg(H₂O)₆](C₇H₅O₆S)₂·2H₂O, the octahedral complex cation lies on an inversion centre and is hydrogen bonded through the coordinated water molecules to the substituted benzenesulfonate monoanions and the water molecules of solvation. These interactions together with a carboxylic acid O—H⋯O(sulfonate) association give a three-dimensional structure.

Related literature

For the structure of the isotypic Mn^II, Cu^II and Co^II dihydrate complexes, see: Ma et al. (2003a ▶,d ▶); Abdelhak et al. (2005 ▶). For the structures of the analogous Co^II, Ni^II and Zn^II tetrahydrate complexes, see: Ma et al. (2003b ▶,c ▶,e ▶).

Experimental

Crystal data

[Mg(H₂O)₆](C₇H₅O₆S)₂·2H₂O
M _r = 602.78
Triclinic,
a = 6.8694 (4) Å
b = 6.9069 (4) Å
c = 14.3950 (8) Å
α = 77.472 (5)°
β = 78.120 (4)°
γ = 70.131 (5)°
V = 620.51 (6) Å³
Z = 1
Mo Kα radiation
μ = 0.33 mm⁻¹
T = 200 K
0.40 × 0.12 × 0.10 mm

Data collection

Oxford Diffraction Gemini-S CCD-detector diffractometer
Absorption correction: multi-scan (CrysAlis PRO; Oxford Diffraction, 2010 ▶) T _min = 0.96, T _max = 0.99
8134 measured reflections
2899 independent reflections
2553 reflections with I > 2σ(I)
R _int = 0.023

Refinement

R[F ² > 2σ(F ²)] = 0.032
wR(F ²) = 0.086
S = 1.14
2899 reflections
209 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.34 e Å⁻³
Δρ_min = −0.43 e Å⁻³

Data collection: CrysAlis PRO (Oxford Diffraction, 2010 ▶); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SIR92 (Altomare et al., 1994 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶) within WinGX (Farrugia, 1999 ▶); molecular graphics: PLATON (Spek, 2009 ▶); software used to prepare material for publication: PLATON.

Supplementary Material

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536811030777/tk2770sup1.cif

e-67-m1194-sup1.cif^{(20.6KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536811030777/tk2770Isup2.hkl

e-67-m1194-Isup2.hkl^{(139.4KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O2—H2⋯O12	0.85 (2)	1.87 (2)	2.632 (2)	149 (2)
O11—H11⋯O53ⁱ	0.79 (3)	1.92 (3)	2.678 (2)	161 (3)
O1W—H11W⋯O12ⁱⁱ	0.85 (2)	1.93 (2)	2.779 (2)	175 (2)
O1W—H12W⋯O51	0.82 (3)	2.00 (3)	2.824 (2)	175 (2)
O2W—H21W⋯O4Wⁱⁱⁱ	0.82 (3)	1.91 (3)	2.728 (3)	173 (3)
O3W—H31W⋯O51^iv	0.75 (3)	2.10 (3)	2.850 (2)	171 (3)
O3W—H32W⋯O4W^v	0.89 (3)	1.87 (3)	2.748 (3)	167 (2)
O4W—H41W⋯O53^vi	0.79 (3)	2.04 (3)	2.803 (2)	162 (3)
O4W—H42W⋯O52	0.84 (3)	1.88 (3)	2.717 (2)	178 (3)

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

Acknowledgments

The authors acknowledge financial support from the Australian Research Council, the Faculty of Science and Technology and the University Library, Queensland University of Technology, and Griffith University.

supplementary crystallographic information

Comment

The title compound, [Mg(H₂O)₆]²⁺ 2(C₇H₅O₆S^-). 2(H₂O) was obtained from the reaction of 3-carboxy-4-hydroxybenzenesulfonic acid (5-sulfosalicylic acid, 5-SSA) with MgCO₃ and the structure is reported here In the structure of this compound (Fig. 1), the octahedral cationic Mg complex cations lie on crystallographic inversion centres [Mg—O, 2.0396 (17)–2.0664 (19) Å]. This complex is isomorphous with other divalent first transition metal–5-SSA complexes with the same basic dihydrate formula [M(H₂O)₆] 2(5-SSA^-). 2(H₂O), [M = Mn (Ma et al., 2003a); Co (Abdelhak et al., 2005); Cu (Ma et al., 2003d)]. These complexes are also similar to the tetrahydrate analogues {[M(H₂O)₆] 2(5-SSA^-). 4(H₂O)}, having triclinic unit cells with comparable cell parameters e.g. Co^II (Ma et al., 2003b) and Ni (Ma et al., 2003c) and Zn (Ma et al., 2003e).

The coordinated water molecules are involved in a number of O—H···O hydrogen-bonding interactions with sulfonate and carboxylate O acceptors of the uncoordinated 5-SSA monoanions and the water molecules of solvation (Table 1) and together with a carboxylic acid O—H···O_sulfonate hydrogen bond form a three-dimensional structure (Fig. 2). In the anion there is the intramolecular cyclic phenol O—H···O_carboxyl hydrogen bond which is invariably present in this monoanion (Ma et al., 2003a). One H of one of the coordinated water molecules (H22W) has no reasonable acceptor in the structure.

Experimental

The title compound was synthesized by heating 218 mg (1 mmol) of 3-carboxy-4-hydroxybenzenesulfonic acid (5-sulfosalicylic acid) with an excess of MgCO₃ in 50 ml of 1:1 ethanol–water under reflux for 10 min. After completion of the reaction, the unreacted MgCO₃ was removed by filtration and the solution was allowed evaporate to incipient dryness at room temperature, giving small colourless prisms of the title compound from which a specimen was cleaved for the X-ray analysis.