8-(Carboxymethoxy)quinolinium nitrate monohydrate

In the title compound, C11H10NO3 +·NO3 −·H2O, the planar 8-carboxymethoxyquinolinium cation, the nitrate anion and the water molecule are dimerized by hydrogen bonds into square building-block units, and then further assembled into two-dimensional gently undulating supramolecular layers.

In the title compound, C 11 H 10 NO 3 + ÁNO 3 À ÁH 2 O, the planar 8carboxymethoxyquinolinium cation, the nitrate anion and the water molecule are dimerized by hydrogen bonds into square building-block units, and then further assembled into twodimensional gently undulating supramolecular layers.

Comment
There are no reports of the title compound but there are several reports on metal compounds involving the ligand 2-(quinolin-8-yloxy)acetate and its derivatives (Czugler & Kalman, 1981;Das et al., 1987;Wang & Lu, 2004;Song et al., 2004). The title compound (Scheme I) contains one cation, one nitrate anion and one water molecule (Fig.1). Fig. 2 shows that the cation, the nitrate anion and water molecule are dimerized by the hydrogen bonds (Table 1) into stable square building block units, and then further assembled into 2D supramolecular layers which are gently undulating.

Experimental
A solution of Cu(NO 3 ) 2 (363 mg, 1.00 mmol) in CH 3 OH (20 ml) was slowly added to a solution of 2-(quinolin-8yloxy)acetic acid (410 mg, 1.95 mmol) in CH 3 OH (10 ml). The resultant blue solution was stirred for 2 h at room temperature and then filtered. Colorless crystals suitable for X-ray diffraction were obtained in two day by slow diffusion of diethyl ether into a dilute solution of the title complex in methanol. The assigned structure was substantiated by elemental analysis; calculated for C 11 H 12 N 2 O 7 : C 46.44, H 4.22, N 9.85%; found: C 46.36, H 4.28, N 9.82%.

Refinement
The structure was solved using direct methods followed by Fourier synthesis. Non-H atoms were refined anisotropically.
All of H atoms except water molecule were placed in idealized positions (C-H = 0.93 or 0.97 Å, O-H = 0.82 Å, N-H = 0.86 Å), forced to ride on the atom to which they are bonded, and were included in the refinement in the riding-model approximation. U iso values were set equal to 1.5U eq (parent atom) for methyl H atoms and to 1.2U eq (parent atom)for all other H atoms. The water H atoms were located in a difference Fourier map, and were refined with distance restraints of O-H = 0.84 (1) and H···H 1.43 (2) Å, but their U iso values were set equal to 1.5 U eq (parent atom O). Fig. 1. The structure of the title compound (I). The atom-numbering scheme is shown and ellipsoids are drawn at the 30% probability level.