Hydrogen-bonded supramolecular motifs in 4,4'-bipyridinium 8-hydroxy-7-iodoquinoline-5-sulfonate dihydrate.

In the title compound, C(10)H(9)N(2)(+).C(9)H(5)INO(4)S(-).2H(2)O, the 4,4'-bipyridine molecule is protonated at one of the pyridine N atoms. These moieties self-assemble into a supramolecular chain along the a axis through N-H.N hydrogen bonds. The quinolinol OH group acts as a donor with respect to a sulfonate O atom [O-H.O(sulfonate)] and acts as an acceptor with respect to a C-H group of ferron [C-H.O(hydroxy)], forming a supramolecular chain along the b axis. These two types of supramolecular chains (one type made up of bipyridine motifs and the other made up of sulfoxine motifs) interact via pi-pi stacking, generating a three-dimensional framework. These chains are further crosslinked by C-H.O hydrogen bonds and O-H.O hydrogen bonds involving water molecules.