Mesogenic Behavior of a Novel Homologous Series: α-4-[4′-n-Alkoxy benzoyloxy] benzoyl-β-4″-chloro Phenyl Ethylenes

A novel homologous series entitled α-4-[4′-n-Alkoxy benzoyloxy] benzoyl β-4″-chloro phenyl ethylenes consists of 12 homologues. The pentyl to tetradecyl homologues are enatiotropically nematogenic and all of the other homologues (methyl to butyl and hexadecyl) are nonmesogenic. The textures of the nematogenic mesophase are threaded or Schlieren in nature. The transition temperatures were determined by an optical polarizing microscope with a heating stage. The phase diagram of the novel series shows a normal behavior with negligible abnormality in trend of the nematic-isotropic transition curve and exhibits an odd–even effect as expected. The nematic thermal stability is 149.4°C on average. The series is nematogenic without any smectogenic character. The mesogenic properties of the novel series are compared with known series that are structurally similar.