2-(4-Fluoro­phen­yl)-2H-chromen-4(3H)-one

In the crystal structure of the title compound, C₁₅H₁₁FO₂, mol­ecules form inversion dimers through pairs of weak C—H...O hydrogen bonds. Dimers oriented in parallel, linked by C—H...π contacts, are arranged in columns along the b axis. The fluoro­phenyl ring and the benzene ring of the 2H-chromen-4(3H)-one unit are inclined to one another by 70.41 (16)°. They are respectively parallel in a given column or almost perpendicular [oriented at an angle of 87.8 (1)°] in neighbouring (inversely oriented) columns, forming a herringbone pattern.

9-(3-Fluoro­phen­oxy­carbon­yl)-10-methyl­acridinium trifluoro­methane­sulfonate monohydrate

In the crystal structure of the title mol­ecular salt, C₂₁H₁₅FNO₂⁺·CF₃SO₃⁻·H₂O, the cations form inversion dimers through π–π inter­actions between the acridine ring systems. These dimers are linked via C—H...O and C—F...π inter­actions to adjacent anions, and by C—H...π and C—F...π inter­actions to neighbouring cations. The water mol­ecule links two sites of the cation by C—H...O inter­actions and two adjacent anions by O—H...O hydrogen bonds. The mean planes of the acridine and benzene ring systems are oriented at a dihedral angle of 15.1 (1)°. The carboxyl group is twisted at an angle of 84.5 (1)° relative to the acridine skeleton. The mean planes of the acridine ring systems are parallel in the crystal.

9-(2-Bromo­phen­oxy­carbon­yl)-10-methyl­acridinium trifluoro­methane­sulfonate

In the crystal structure of the title compound, C₂₁H₁₅BrNO₂⁺·CF₃SO₃⁻, adjacent cations are linked through C—Br...π and π–π contacts [centroid–centroid distance = 3.744 (2) Å], and neighbouring cations and anions via C—H...O, C—F...π and S—O...π inter­actions. The acridine and benzene ring systems are oriented at a dihedral angle of 18.7 (1)°. The carb­oxy group is twisted at an angle of 69.3 (1)° relative to the acridine skeleton. The mean planes of adjacent acridine moieties are either parallel or inclined at an angle of 27.8 (1)° in the lattice.