5,5′-(Ethyne-1,2-di­yl)diisophthalic acid dimethyl sulfoxide tetra­solvate

In the title compound, C₁₈H₁₀O₈·4C₂H₆OS, the mid-point of the triple bond of the main mol­ecule is located on a special position, i.e. about an inversion center. The carboxyl groups are twisted slightly out of the planes of the aromatic rings to which they are attached, making dihedral angles of 24.89 (1) and 7.40 (2)°. The cystal packing features strong O—H...O hydrogen bonds, weaker C—H...O inter­actions and O...S contacts [3.0981 (11) Å] and displays channel-like voids extending along the a-axis direction which contain the dimethyl sulfoxide solvent mol­ecules.

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.