Sodium (1R)-d-glucit-1-ylsulfonate monohydrate

The title salt, Na+·C6H13O9S−·H2O, crystallizes with three independent cations, molecular anions and solvent water molecules in the asymmetric unit. This crystalline monohydrate addition product, formed by reaction of d-glucose and sodium hydrogen sulfite in water, forms a three-dimensional network through complex cation coordination and extensive intermolecular hydrogen bonding. Each of the independent molecules has an open-chain structure with the carbon chains adopting a sickle-like conformation, similar to that found in the potassium salt [Cole et al. (2001 ▶). Carbohydr. Res. 335, 1–10], but there are significant differences in the patterns of complexation.

The title salt, Na + ÁC 6 H 13 O 9 S À ÁH 2 O, crystallizes with three independent cations, molecular anions and solvent water molecules in the asymmetric unit. This crystalline monohydrate addition product, formed by reaction of d-glucose and sodium hydrogen sulfite in water, forms a three-dimensional network through complex cation coordination and extensive intermolecular hydrogen bonding. Each of the independent molecules has an open-chain structure with the carbon chains adopting a sickle-like conformation, similar to that found in the potassium salt [Cole et al. (2001). Carbohydr. Res. 335, 1-10], but there are significant differences in the patterns of complexation.

Related literature
For the first syntheses of the title compound, see: Braverman (1953); Ingles (1959). For evidence of the acyclic nature of such compounds, see: Ingles (1959Ingles ( , 1969. For the synthesis and crystallographic properties of the corresponding potassium salts of d-glucose and d-mannose, see: Cole et al. (2001). For an additional discussion on the potassium salt, see: Haines & Hughes (2010). For the crystallographic study of potassium (1S)-d-galactit-1-ylsulfonate, see: Haines & Hughes (2010).
form of the crystalline sulfonic salts derived from D-glucose and D-mannose with potassium bisulfite was only proved conclusively more recently by X-ray crystallographic studies (Cole et al., 2001). A study on the D-galactose compound (Haines & Hughes, 2010) also proved its acyclic nature.
Storage of a concentrated aqueous solution of D-glucose and equimolar sodium bisulfite (generated in the aqueous solution from sodium metabisulfite) at 277 K for several months, gave crystals of sodium (1R)-D-glucit-1-ylsulfonate monohydrate, 1, with properties (mp and [α] D ) in agreement with those reported (Braverman, 1953;Ingles, 1959).
The title adduct ( Fig. 1) crystallizes with three independent molecules per asymmetric unit; in contrast, the potassium adduct, also a monohydrate, has only one (Cole et al., 2001). Each of the three molecules adopts a sickle-like conformation with gauche conformations in the region C1-C2-C3-C4. Other torsion angles in the chains (which include the sulfur atom), all have values close to 180°, i.e. with anti conformations. Molecule B differs from A and C in having atom O16 approximately anti to H15; in A and C, atoms O6 and H5 adopt a gauche relationship about the C5-C6 bond.
In the crystal, the groups of three molecules, A, B, and C, are repeated by translation parallel to the b axis (Fig. 1).
The potassium compound also has the R configuration at C1 (Cole et al., 2001) but coordination of the sodium cation is distinctly different from that around the potassium ion. The sodium ions are each hexa-coordinated with oxygen atoms in the title compound [see Fig. 2 for the coordination pattern of Na2], with three different carbohydrate ligands providing five O atoms and a water molecule the sixth. For each sodium ion, one carbohydrate residue provides three of these O atoms, O1, O2 and a sulfonate oxygen O7; the other two oxygen atoms are provided by sulfonate O atoms from the two other residues. In contrast, the potassium compound has the cation coordinated to seven O atoms which are provided by four different carbohydrate molecules and a water molecule (Cole et al., 2001;Haines & Hughes, 2010).
Extensive intermolecular hydrogen bonding involves all three of the distinct anions, and this is indicated for one anion in Fig. 2. Every hydroxyl group is involved as a donor group in a hydrogen bond, and all except those at C1 (which are coordinated to sodium ions) are acceptors. The hydrogen atom H1O, of the hydroxy group at C1 of each anion (see Table   1), is involved in a bifurcated hydrogen bond to oxygen atoms of the hydroxy groups at C2 and C3 in an adjacent molecule ( Figs. 1 and 2). The hydrogen bonds of the OH groups at C3 and C4 in each molecule are directed to oxygen atoms O5 and O4 in adjacent molecules. From molecules B and C, the hydrogen bonds involving atoms O3 and O5 are both accepted by O5 of an adjacent molecule, whereas the corresponding bonds from O3 and O5 of molecule A are accepted by O5 and O6, respectively, of the adjacent molecule. The remaining OH groups are linked less regularly, but all supplementary materials sup-2 Acta Cryst. (2012). E68, m377-m378 are involved in hydrogen bonds to main-chain OH groups, sulfonate O atoms or water molecules.
The three water molecules all have an approximately tetrahedral bonding pattern. Each water O atom is coordinated with a sodium ion and bonded to two hydrogen atoms, one of which forms a hydrogen bond to an O8 sulfonate atom, the other to either an O6 atom or an O7 sulfonate atom; the fourth site is the acceptor end of a hydrogen bond. This is shown for atom O32 in Fig. 2.
A simplified view along the crystallographic c axis (Fig. 3) shows the remarkable way in which a network of sulfonate residues is linearly linked (parallel to the b axis) through two of their oxygen atoms, O8 and O9, by rows of sodium atoms; cross-links, parallel to the a axis, between these chains are made through the third of the sulfonate oxygen atoms, O7. The complex coordination and hydrogen bonding leads to a complex, extensive, three-dimensional network.

Refinement
The hydroxyl H atoms were located in difference Fourier maps and were freely refined. The C-bound H atoms were included in calculated positions and treated as riding atoms: C-H = 0.98 and 0.97 Å for CH and CH 2 H atoms, respectively, with U iso (H)= 1.2U eq (C).
The atom numbering scheme is shown; the atoms of the other molecules are numbered correspondingly, with C, O and S atom numbers n+10 and n+20. The water molecules are labelled O31, O32 and O33. Symmetry codes:

Figure 3
View down the c axis, showing the sodium ions, lying in a sheet parallel to (001), with all their coordinated atoms linked by bridging sulfonate groups. Symmetry codes: Sodium (1R,2R,3S,4R,5R)-1,2,3,4,5,6-hexahydroxyhexane-1-sulfonate monohydrate Crystal data Na + ·C 6 H 13 O 9 S − ·H 2 O M r = 302.23 Orthorhombic, P2 1 2 1 2 1 Hall symbol: P 2ac 2ab a = 8.81958 (9) Å b = 16.8420 (2)   ] -). The latter corresponds to the ion of the product formed by reaction between the sulfonate and D-glucose with displacement of sodium bisulfite; some decomposition of the sulfonate to afford D-glucose undoubtedly occurs in aqueous solution. Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'s involving l.s. planes. Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > 2σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.