Crystal structure and Hirshfeld surface analysis of 4,4'-dimethoxybiphenyl-3,3',5,5'-tetracarboxylic acid dihydrate.

In the crystal of the title compound, C₁₈H₁₄O₁₀⋅2H2O, the arene rings of the biphenyl moiety are tilted at an angle of 24.3 (1)°, while the planes passing through the carboxyl groups are rotated at angles of 8.6 (1) and 7.7 (1)° out of the plane of the benzene ring to which they are attached. The crystal structure is essentially stabilized by O--H⋯O bonds. Here, the carboxyl groups of neighbouring host molecules are connected by cyclic R₂²(8) synthons, leading to the formation of a three-dimensional network. The water molecules in turn form helical supramolecular strands running in the direction of the crystallographic caxis (chain-like water clusters). The second H atom of each water molecule provides a link to a methoxy O atom of the host molecule. A Hirshfeld surface analysis was performed to quantify the contributions of the different intermolecular interactions, indicating that the most important contributions to the crystal packing are from H⋯O/O⋯H (37.0%), H⋯H (26.3%), H⋯C/C⋯H (18.5%) and C⋯O/O⋯C (9.5%) interactions. [ABSTRACT FROM AUTHOR]