cis-Bis(2,2′-bipyridine-4,4′-dicarboxylic acid-κ2N,N′)dichlororuthenium(II) monohydrate

The crystal structure of the title compound, [RuCl2(C12H8N2O4)2]·H2O, which is a precursor of the dye for dye-sensitized solar cells, is composed of a ruthenium(II) complex mol­ecule containing 2,2′-bi­pyridine-4,4′-di­carboxyl­ic acid (H2dcbpy) as a ligand and an uncoordinated water mol­ecule. The overlapped arrangement and the separation of 3.34 (7) Å suggest π–π stacking between parallel H2dcbpy ligands in neighboring complex mol­ecules. A three-dimensional network is formed by intermolecular O—H⋯O and O—H⋯Cl hydrogen bonds and π–π stacking between neighboring complex mol­ecules.