Synthesis, characterization and theoretical considerations of a novel class of banana-shaped compounds with liquid crystal properties

As analogues of banana-shaped compounds, two novel series of bis(acylated) resorcinol derivatives incorporating two and four additional benzene rings, respectively, were synthesized. In the first series of compounds resorcinols were acylated with 4-alkoxycinnamoyl chlorides, whereas in the second series, 1,3-bis(4-hydroxybenzoyloxy)-4-chlorobenzene was prepared first, and subsequently, 4-alkoxycinnamoyl groups were introduced. In the cases of five-ring compounds 34-39, valuable liquid crystalline properties were detected. Nematic phases could be observed within a wide range of temperatures. Moreover, of these compounds, the hexadecyloxy derivative displayed a short monotropic smectic phase with a latticed texture. Molecular modeling studies have indicated that compounds of five-ring structures of type 34-39 may have energy minima in which the three planar building moieties of the central bisacylated resorcinol unit are not necessarily coplanar. (C) 2001 Elsevier Science B.V. All rights reserved.