Crystal structure of (E)-4-{4-[eth­yl(2-hydroxy­eth­yl)amino]­styr­yl}-1-methyl­pyridinium nitrate hemihydrate

The asymmetric unit of the title compound, C18H23N2O(+)·NO3 (-)·0.5H2O, contains two independent 4-{4-[eth-yl(2-hy-droxy-eth-yl)amino]-styr-yl}-1-methyl-pyridin-1-ium cations, two nitrate anions and one lattice water mol-ecule. In the cations, the pyridine ring is twisted with respect by 7.98 (12) and 18.42 (10)° to the benzene ring. In the crystal, the cations, the anions and the lattice water mol-ecules are linked by O-H⋯O hydrogen bonds and weak C-H⋯O hydrogen bonds, forming a three-dimensional supra-molecular architecture. π-π stacking occurs between pyridine and benzene rings of adjacent cations, the centroid-centroid distances being 3.8169 (15) and 3.8663 (14) Å. In the crystal, one of the independent cations is disordered, the central vinyl unit and the terminal hy-droxy-lethyl group being disordered over two sets of sites with site occupancy factors of 0.600 (6) and 0.400 (6).