(E)-N′-(2,4,6-Trihydroxybenzylidene)isonicotinohydrazide sesquihydrate

In the title compound, C(13)H(11)N(3)O(4)center dot 1.5H(2)O, the pyridine ring forms a dihedral angle of 1.50 (6)degrees with the benzene ring. An intramolecular O-H center dot center dot center dot N hydrogen bond forms a six-membered ring with an S(6) ring motif. In the crystal structure, one water molecule is disordered over two positions around an inversion centre with site-occupancy factors of 0.5. Intermolecular O-H center dot center dot center dot N, O-H center dot center dot center dot O, N-H center dot center dot center dot O and C-H center dot center dot center dot O hydrogen bonds consolidate the structure into a three dimensional network. A pi-pi stacking interaction with a centroid-centroid distance of 3.5949 (7) angstrom is also present.