9-(2,6-Dibromo­phenoxy­carbonyl)-10-methyl­acridinium trifluoro­methane­sulfonate

In the title compound, C₂₁H₁₄Br₂NO₂⁺·CF₃O₃S⁻, adjacent cations are oriented either parallel or antiparallel. Together with the CF₃O₃S⁻ anions, the anti­parallel-oriented cations form layers in which the ions are linked via a network of C—H...O (O from the anions) and π–π inter­actions (between the benzene rings). These layers, in turn, are linked via a network of five multidirectional π–π inter­actions between the acridine rings, and the crystal structure is stabilized by electrostatic inter­actions between the ions. The acridine and independent benzene rings are mutually oriented at an angle of 35.9 (3)°.

2,6-Dibromo­phenyl acridine-9-carboxyl­ate

Adjacent mol­ecules of the title compound, C₂₀H₁₁Br₂NO₂, are oriented either parallel or antiparallel; in the latter case, there are four inter­molecular π–π inter­actions between acridine rings. The acridine and benzene ring systems are inclined at an angle of 41.2 (2)° to each other. There is also a short inter­molecular Br...Br contact.

2,6-Diiodo­phenyl acridine-9-carboxyl­ate

In the ortho­rhom­bic crystalline phase of the title compound, C₂₀H₁₁I₂NO₂, all the benzene rings are parallel, whereas the acridine systems are either parallel or perpendicular to each other; this generates a herring-bone pattern. The acridine systems and benzene rings are inclined at an angle of 45.5 (1)° to each other, and the acridine systems and carboxyl­ate groups are inclined at an angle of 54.2 (1)°. Oppositely oriented consecutive mol­ecules, with π–π inter­actions between their acridine systems and I...I and I...N contacts, are aligned in stacks along the a axis. These stacks, inter­acting through π–π contacts between benzene rings, are arranged in layers.