4-[(E)-2-(2,4-Dichlorobenzylidene)hydrazin-1-yl]quinolin-1-ium chloride monohydrate

In the title hydrated salt, C16H12Cl2N3 +·Cl−·H2O, there is a small twist in the cation as seen in the torsion angle linking the benzene ring to the rest of the molecule [171.96 (17)°]. In the crystal, the quinolinium H atom forms a hydrogen bond to the lattice water molecule, which also forms hydrogen bonds to two Cl− anions. Each Cl− ion also accepts a hydrogen bond from the hydrazine H atom. The three-dimensional architecture is also stabilized by π–π interactions between centrosymmetrically related quinoline residues [centroid–centroid distance = 3.5574 (11) Å].

In the title hydrated salt, C 16 H 12 Cl 2 N 3 + ÁCl À ÁH 2 O, there is a small twist in the cation as seen in the torsion angle linking the benzene ring to the rest of the molecule [171.96 (17) ]. In the crystal, the quinolinium H atom forms a hydrogen bond to the lattice water molecule, which also forms hydrogen bonds to two Cl À anions. Each Cl À ion also accepts a hydrogen bond from the hydrazine H atom. The three-dimensional architecture is also stabilized byinteractions between centrosymmetrically related quinoline residues [centroid-centroid distance = 3.5574 (11) Å ].
The asymmetric unit of (I), Fig There are a number of hydrogen-bonding interactions operating in the crystal structure of (I), Table 1. The pyridinium-H forms a hydrogen bond to the water molecule which links two chloride anions via O-H···Cl interactions. Through a centre of inversion, an eight-membered {···HOH···Cl} 2 synthon is formed. Finally, the hydrazine-H atom forms a hydrogen bond to the chloride atom. The three-dimensional architecture is also stabilized by π-π interactions between centrosymmetrically related quinolinyl residues [centroid···centroid distance = 3.5574 (11) Å for symmetry operation: 1 -

Experimental
The compound was prepared from 7-chloro-4-quinolinylhydrazone with 2,5-dimethoxybenzaldehyde (Montenegro et al., 2012). The crystals used in the structure determination were grown from an ethanol solution of the compound.

Refinement
The C-bound H atoms were geometrically placed (C-H = 0.95 Å) and refined as riding with U iso (H) = 1.2U eq (C). The N-

Figure 1
The molecular structure showing the atom-labelling scheme and displacement ellipsoids at the 50% probability level.   Special details Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'s involving l.s. planes. Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > 2σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.