7-Chloro-4-[(E)-N′-(4-fluorobenzylidene)hydrazinyl]quinoline monohydrate

The molecule of the title hydrate, C16H11ClFN3·H2O, is slightly twisted, as indicated by the dihedral angle of 9.55 (10)° formed between the quinoline ring system and the benzene ring. The conformation about the C=N double bond is E, and the amine-H atom is oriented towards the quinoline residue. In the crystal structure, the water molecule accepts an N—H⋯O and makes two O—H⋯Nquinoline hydrogen bonds, generating a two-dimensional array in the ab plane, which is further stabilized by C—H⋯O interactions. The most significant contacts between layers are of the type C—H⋯F.

The molecule of the title hydrate, C 16 H 11 ClFN 3 ÁH 2 O, is slightly twisted, as indicated by the dihedral angle of 9.55 (10) formed between the quinoline ring system and the benzene ring. The conformation about the C N double bond is E, and the amine-H atom is oriented towards the quinoline residue. In the crystal structure, the water molecule accepts an N-HÁ Á ÁO and makes two O-HÁ Á ÁN quinoline hydrogen bonds, generating a two-dimensional array in the ab plane, which is further stabilized by C-HÁ Á ÁO interactions. The most significant contacts between layers are of the type C-HÁ Á ÁF.
The use of the EPSRC X-ray crystallographic service at the University of Southampton, England and the valuable assistance of the staff there is gratefully acknowledged. JLW acknowledges support from CAPES (Brazil).
Twists in the molecule are evident about the N2-C3 and C10-C11 bonds as seen in the values of the N3-N2-C3-C2 and N3-C10-C11-C12 torsion angles of 6.9 (4) and -6.6 (4) °, respectively. As observed in related systems, the amine-H is orientated over the quinoline residue (Kaiser et al. 2009;de Ferreira et al., 2009). The conformation about the N3═C10 double bond is E. The molecule crystallizes as a hydrate and the latter species is pivotal in stabilizing the crystal structure. Thus, the water-H atoms form donor O-H···N hydrogen bonds to quinoline-N atoms derived from two molecules. At the same time, the water-O atom accepts a N-H···O hydrogen bond from the amine-N2 of another molecule.

Experimental
A solution of 7-chloro-4-hydrazinoquinoline (0.20 g, 1.0 mmol) and 4-fluorobenzaldehyde (0.15 g, 1.2 mmol) in EtOH (5 ml) was maintained at room temperature overnight and rotary evaporated. The solid residue, was washed with cold Et 2 O (3 x 10 ml) and recrystallized from EtOH m.pt. 518-519 K, lit. value 518 K (Pellerano et al., 1976), yield 74%. The sample for the X-ray study was slowly grown from moist EtOH and was found to be the monohydrate. The amine-and C-bound H atoms were geometrically placed (N-H = 0.88 Å and C-H = 0.95 Å) and refined as riding with U iso (H) = 1.2U eq (C). The water-bound H atoms were located from a difference map and refined (O-H = 0.84 (1) Å) with U iso (H) = 1.5U eq (O). Fig. 1. The molecular structure of both components comprising the asymmetric unit of (I) 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 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 Rfactors(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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq