2,5‐Dibromopyridine as a key building block in the synthesis of 2,5‐disubstituted pyridine‐based liquid crystals

Abstract

Fifteen 2,5‐disubstituted pyridine based liquid crystals were synthesized exploiting the different reactivities of the bromine atoms in 2,5‐dibromopyridine under Negishi coupling conditions. Convenient approaches to both 2‐iodo‐5‐alkyl‐pyridines and 2‐alkyl‐5‐bromopyridines were also developed. The liquid crystalline behaviour of the synthesized materials was investigated using DSC and polarizing microscopy. The charge mobility of 2‐(4‐heptyloxyphenyl)‐5‐heptylpyridine was measured using the time of flight technique.

Acknowledgement

We would like to thank Dr Alex Seed for use of the microscope and assistance in the phase assignment of some of these liquid crystals. Studies of liquid crystalline semiconductors at Kent State University have been partly supported by a NEDO International Joint Research Grant.