Liquid crystalline properties of penta(p‐phenylene)s modified with short lateral and long terminal alkoxy chains

Abstract

A series of penta(p‐phenylene)s modified with short and long alkoxy groups was synthesized via palladium complex‐catalysed cross‐coupling reactions. Molecules substituted with butoxy groups in the central ring showed a nematic phase characterized by a schlieren optical texture, whereas those molecules lacking lateral groups, or substituted with shorter than butoxy groups, did not exhibit liquid crystallinity. Also, it was determined that both the mesophase stability and the clearing point were strongly dependent on the length of the terminal chains. Finally, optical studies of these compounds indicated that the observed light absorption/emission characteristics are independent of the chain lengths.

Acknowledgement

The authors wish to thank the CONACYT of Mexico for supporting this work (projects 35163‐U and 437541‐Y) and for the grant (ref. 68941) to L. L.‐L. during her PhD studies at CIQA. We also wish to thank Claudia V. Reyes‐Castañeda for helpful assistance in the synthesis of some compounds studied in this work.