Crystal structure of hexaaquanickel(II) bis{5-bromo-7-[(2-hydroxyethyl)amino]-1-methyl-6-oxidoquinolin-1-ium-3-sulfonate} monohydrate

The asymmetric unit of the title compound, [Ni(H 2 O) 6 ](C 12 H 12 BrN 2 O 5 S) 2 ·H 2 O, contains a half hexaaquanickel(II) complex cation with the Ni II ion lying on an inversion center, one 5-bromo-7-[(2-hydroxyethyl)amino]-1-methyl-6-oxidoquinolin-1-ium-3-sulfonate ( QAO ) anion and a half lattice water molecule on a twofold rotation axis. In the crystal, QAO anions are stacked in a column along the c axis by π–π stacking interactions [centroid–centroid distances 3.5922 (10)–3.7223 (11) Å]. The columns are interlinked by hexaaquanickel(II) cations through O—H...O and N—H...O hydrogen bonds.