A new series of liquid‐crystalline bi‐1,3,4‐oxadiazole derivatives: synthesis and mesomorphic behaviour

Abstract

Symmetrical bi‐1,3,4‐oxadiazole derivatives, namely 5,5′‐bis(phenyl 4‐alkoxybenzoate)‐2,2′‐bi‐1,3,4‐oxadiazole (BBOXD‐n, n = 6, 10, 14, 16), were synthesised. All BBOXD‐n exhibited remarkably stable SmC phases by virtue of the high transition enthalpies of SmC–I. In addition, BBOXD‐6 and BBOXD‐10 showed an enantiotropic nemetic phase with enthalpies of the N–I transition up to 5.16 kJ mol⁻¹. As confirmed by wide‐angle X‐ray diffraction analysis and MM2, molecules of BBOXD‐n showed high‐angle tilting (55–57°) within their smectic C phases.

Keywords:

• large‐angle tilted SmC phase
• bi‐1,3,4‐oxadiazole
• remarkably stable nemetic and smectic C phases

Acknowledgments

The authors are grateful to the National Science Foundation Committee of China (Project 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 20050183057), and Project 985‐Automotive Engineering of Jilin University for their financial support of this work.