Synthesis and crystal structure of [Ni(H2O)6](C19H17O9S)2·2H2O

A water soluble flavonoid sulfate, [Ni(H2O)6](C19H17O9S)2·2H2O was synthesized and its structure was determined by single-crystal X-ray diffraction analysis. The crystal of it belongs to triclinic crystal system, space group P–1. The results show that the title compound consists of [Ni(H2O)6]2+, C19H17O6SO3 − and H2O. Ni(II) is located on the symmetry center and octahedrally coordinated by six water molecules. A variety of hydrogen bonds among [Ni(H2O)6]2+, C19H17O6SO3 − and the lattice water molecules build a hydrophilic region. Aromatic π–π stacking interactions assemble isoflavone skeletons into a column and the columns form a hydrophobic region of the title compound. The sulfo-groups bridge the hydrophilic regions and the hydrophobic regions as well as the inorganic components and organic components. Hydrogen bonds, $$\pi \cdots \pi$$ stacking interactions and the electrostatic interactions between cation [Ni(H2O)6]2+ and anion sulfonate C19H17O6SO3 − lead the moieties to a three-dimensional structure.