9-Ethyl-10-methyl­acridinium trifluoro­methane­sulfonate

In the mol­ecule of the title compound, C16H16N+·CF3SO3 −, the central ring adopts a flattened-boat conformation, and the two aromatic rings are oriented at a dihedral angle of 3.94 (2)°. In the crystal structure, weak inter­molecular hydrogen bonds link the mol­ecules. There are π–π contacts between the aromatic rings and the central ring and one of the aromatic rings [centroid–centroid distances = 3.874 (2), 3.945 (2) and 3.814 (2) Å]. There is also an S—O⋯π contact between the central ring and one of the O atoms of the anion

9-(4-Methyl­phenoxy­carbon­yl)-10-methyl­acridinium trifluoro­methane­sulfonate

In the crystal structure of the title compound, C22H18NO2 +·CF3SO3 −, adjacent cations are linked through C—H⋯π and π–π inter­actions, and the cations and anions are connected by C—H⋯O and C—F⋯π inter­actions. The acridine and benzene ring systems are oriented at a dihedral angle of 3.0 (1)°. The carboxyl group is twisted at an angle of 83.1 (1)° relative to the acridine skeleton. The mean planes of adjacent acridine units are parallel or inclined at an angle of 75.2 (1)° in the crystal structure

10-Methyl-9-phenoxy­carbonyl­acridinium trifluoro­methane­sulfonate monohydrate

In the crystal structure of the title compound, C21H16NO2 +·CF3SO3 −·H2O, the anions and the water mol­ecules are linked by O—H⋯O inter­actions, while the cations form inversion dimers through π–π inter­actions between acridine ring systems. These dimers are linked by C—H⋯O and C—F⋯π inter­actions to adjacent anions, and by C—H⋯π inter­actions to neighboring cations. The water mol­ecule links two H atoms of the cation by C—H⋯O inter­actions and two adjacent anions by O—H⋯O inter­actions. 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)°

9-Phenyl-10H-acridinium trifluoro­methane­sulfonate

In the crystal structure of the title compound, C19H14N+·CF3SO3 −, the cations are linked to each other by very weak C—H⋯π inter­actions, while the cations and anions are connected by N—H⋯O, C—H⋯O and S—O⋯π inter­actions. The acridine ring system and the phenyl ring are oriented at an angle of 80.1 (1)° with respect to each other. The mean planes of adjacent acridine units are either parallel or inclined at an angle of 35.6 (1)°. The trifluoro­methane­sulfonate anions are disordered over two positions; the site occupancy factors are 0.591 (8) and 0.409 (8)

9-[(2,6-Dimethoxy­phen­oxy)carbon­yl]-10-methyl­acridinium trifluoro­methane­sulfonate

In the crystal structure of the title compound, C23H20NO4 +·CF3SO3 −, the cations are linked through C—H⋯O, C—H⋯π and π–π inter­actions [centroid-centroid distances = 3.641 (2) and 3.885 (2) Å]. The cation and the anion are held together by C—H⋯O and S—O⋯π inter­actions. The acridine ring system and the benzene ring in the cation are oriented at a dihedral angle of 8.7 (1)°. The carb­oxy group is twisted at an angle of 83.2 (1)° relative to the acridine skeleton

9-(Biphenyl-4-yl­oxycarbon­yl)-10-methyl­acridinium trifluoro­methane­sulfonate

In the crystal structure of the title compound, C27H20NO2 +·CF3SO3 −, the cations form inversion dimers through π–π inter­actions between the acridine ring systems [centroid-centroid distances = 3.668 (2)–3.994 (2) Å]. These dimers are further linked by C—H⋯O and C—H⋯π inter­actions. The cation and the anion are connected by C—H⋯O inter­actions. The mean plane of the acridine ring system makes dihedral angles of 10.6 (1) and 82.5 (1)°, respectively, with the adjacent phenyl ring and the carb­oxy group. The two phenyl rings of the biphenyl group are oriented at 42.9 (1)°

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

In the crystal structure of the title compound, C23H20NO2 +·CF3SO3 −, the cations form inversion dimers through π–π inter­actions between the acridine ring systems. These dimers are further linked by C—H⋯π inter­actions. The cations and anions are connected by C—H⋯O and C—F⋯π inter­actions. The acridine and benzene ring systems are oriented at a dihedral angle of 20.8 (1)°. The carboxyl group is twisted at an angle of 66.2 (1)° relative to the acridine skeleton. The mean planes of adjacent acridine units are parallel in the lattice

2-(Furan-2-yl)-3-hy­droxy-4H-chromen-4-one

In the crystal structure of the title compound, C13H8O4, the inversely oriented mol­ecules form inversion dimers through pairs of O—H⋯O hydrogen-bonding inter­actions. An intramolecular O—H⋯O hydrogen bond occurs. In the packing of the mol­ecules, the nearly planar 2-(furan-2-yl)-4H-chromene units [dihedral angle between the chromene and furan rings = 3.8 (1)°] are either parallel or inclined at an angle of 80.7 (1)°

2-Meth­oxy-9-phenoxy­acridine

The mol­ecules in the crystal structure of the title compound, C20H15NO2, form inversion dimers connected through the C—H⋯N and π–π inter­actions. These dimers are further linked by C—H⋯π inter­actions. The meth­oxy group is nearly coplanar with the acridine ring system [dihedral angle = 4.5 (1)°], whereas the phen­oxy fragment is nearly perpendicular to it [dihedral angle = 85.0 (1)°]. The mean planes of the acridine ring systems are either parallel or inclined at angles of 14.3 (1), 65.4 (1) and 67.3 (1)° in the crystal