Non‐symmetric liquid crystal dimers containing the 4‐nitrobenzohydrazide group: synthesis and mesomorphic behaviour

Abstract

The synthesis and mesomorphic behaviour are reported of a new series of dimers containing 4‐nitrobenzohydrazide and azobenzene groups as the mesogenic units. These non‐symmetric liquid crystal dimers are found to exhibit a monolayer smectic A phase (SmA₁). Lateral hydrogen bonding and strong dipole–dipole interactions are shown to be the major driving forces for the formation of the SmA₁ phase. The present study indicates that the intermolecular interactions and thus the mesophase morphology of the liquid crystal dimers can be controlled by the appropriate selection of the molecular fragments capable of forming H‐bonds.

Keywords:

• liquid crystal dimers
• hydrogen bonding
• hydrazide
• derivatives
• azobenzene

Acknowledgements

The authors are grateful to the National Science Foundation Committee of China (project No. 50373016), Program for New Century Excellent Talents in Universities of China Ministry of Education, Special Foundation for PhD Program in Universities of China Ministry of Education (Project No. 20050183057) and Project 985‐Automotive Engineering of Jilin University for their financial support of this work.