10-Methyl-9-phenoxy-carbonyl-acridinium trifluoro-methane-sulfonate monohydrate

In the crystal structure of the title compound, C(21)H(16)NO(2) (+)·CF(3)SO(3) (-)·H(2)O, the anions and the water mol-ecules are linked by O-H⋯O inter-actions, while the cations form inversion dimers through π-π inter-actions between acridine ring systems. These dimers are linked by C-H⋯O and C-F⋯π inter-actions to adjacent anions, and by C-H⋯π inter-actions to neighboring cations. The water mol-ecule links two H atoms of the cation by C-H⋯O inter-actions and two adjacent anions by O-H⋯O inter-actions. The acridine and benzene ring systems are oriented at 15.6 (1)°. The carboxyl group is twisted at an angle of 77.0 (1)° relative to the acridine skeleton. The mean planes of the adjacent acridine units are either parallel or inclined at an angle of 18.4 (1)°.