2-{[2,8-Bis(trifluoro­meth­yl)quinolin-4-yl](hy­droxy)meth­yl}piperidin-1-ium 3-amino-5-nitro­benzoate sesquihydrate

The asymmetric unit of the title salt solvate, C(17)H(17)F(6)N(2)O(+)·C(7)H(5)N(2)O(4) (−)·1.5H(2)O, comprises a piperidin-1-ium cation, a 3-amino-5-nitro­benzoate anion, and three fractionally occupied [i.e. 0.414 (3), 0.627 (6) and 0.459 (5)] disordered water mol­ecules of solvation. The cation has an L shape with a C—C—C—C torsion angle of −102.9 (3)° for the atoms linking the quinolinyl group to the rest of the cation. In the anion, the carboxyl­ate and nitro groups are essentially coplanar with the benzene ring [O—C—C—C torsion angle = 179.7 (2)° and O—N—C—C torsion angle = −3.9 (3)°]. In the crystal, extensive O—H⋯O, O—H⋯F and N—H⋯·O hydrogen bonding leads to the formation of a layer in the ab plane.