Tris(N-salicylideneanilines) [TSANs] exhibiting a room temperature columnar mesophase: synthesis and characterization

Tris(N-salicylideneaniline) derivatives with peripheral branched alkyl chains, existing in their C3h and Cs symmetric keto-enamine tautomeric forms, synthesized by condensing alkoxyanilines with 1,3,5-triformylphloroglucinol, display a technologically important columnar liquid crystal phase over a wide thermal interval (∼160 °C) well below and above room temperature, as established by optical and calorimetric studies.