5-(Naphthalen-1-yl)isophthalic acid–dimethyl sulfoxide–water (2/1/2)

The asymmetric unit of the title compound, 2C18H12O4·C2H6OS·2H2O, consists of four crystallographically independent molecules of 5-(naphthalen-1-yl)isophthalic acid, two dimethyl sulfoxide and four water molecules. The dihedral angles formed by the the planes of the aromatic fragments of the organic molecules range from 57.4 (1) to 59.1 (1)°. In the crystal, multiple O—H⋯O hydrogen bonds link the water molecules with the carbonyl and sulfoxide groups, giving rise to double ribbons along the b-axis direction.

The asymmetric unit of the title compound, 2C 18 H 12 O 4 Á-C 2 H 6 OSÁ2H 2 O, consists of four crystallographically independent molecules of 5-(naphthalen-1-yl)isophthalic acid, two dimethyl sulfoxide and four water molecules. The dihedral angles formed by the the planes of the aromatic fragments of the organic molecules range from 57.4 (1) to 59.1 (1) . In the crystal, multiple O-HÁ Á ÁO hydrogen bonds link the water molecules with the carbonyl and sulfoxide groups, giving rise to double ribbons along the b-axis direction.

Refinement
Aromatic H atoms were positioned geometrically and allowed to ride on their parent atoms, with C-H = 0.95 Å and U iso = 1.2 U eq (C).

Figure 1
Asymmetric unit of the title compound, showing the atom numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.

Figure 2
A view along the a-axis of the crystal packing of the title compound. Hydrogen bond interactions are presented as broken lines. Oxygen atoms are specified as dotted circles, sulfur atoms as shaded circles. Non-relevant hydrogen atoms are omitted.

Data collection
Bruker Kappa APEXII CCD diffractometer Radiation source: fine-focus sealed tube Graphite monochromator φ and ω scans 39842 measured reflections 15284 independent reflections 12600 reflections with I > 2σ(I) R int = 0.043 θ max = 28.1°, θ min = 1.6°h  (5) Special details 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 > σ(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. Distances for O-H bonds of the water molecules were restraint of 0.85 (0.01) Angstroms.