THE HOMOLOGOUS SERIES OF SOME NEW 6-RING DOUBLE-SWALLOW-TAILED COMPOUNDS

Recently we reported three homologous six-ring double-swallow-tailed c ompounds. For one homologue we observed the unusual phase sequence re- entrant smectic C-D-ob-smectic C-nematic. For this reason, results for a more complete homologous series are now presented. It was found tha t the phase behaviour can be compared with some series of biforked com pounds. The lower members of the series exhibit nematic and smectic C phases, whereas the long-chain homologues form columnar phases. For th ree members of the series with intermediate lengths of the terminal ch ains, lamellar (S-C) and columnar (D-ob) phases occur for the same sub stance.