Synthesis and mesomorphic studies on the series of 2-(4-alkoxyphenyl)-5-phenylpyridines and 2-(6-alkoxynaphthalen-2-yl)-5-phenylpyridines

Abstract

Two homologous series of pyridine-containing liquid crystalline compounds, 2-(4-alkoxyphenyl)-5-phenylpyridines (nO-PPyP, n = 3–7) and 2-(6-alkoxynaphthalen-2-yl)-5-phenylpyridines (mO-NpPyP, m = 3–7), were synthesised. The preparation of compounds of nO-PPyP and mO-NpPyP was completed in a short two-step reaction with overall yields of about 71–80% and 36–40%, respectively. Spectral analyses were in accordance with the expected structures. Their thermotropic behaviours were studied using polarising optical microscopy (POM) and further confirmed by differential scanning calorimetry (DSC). Experimental evidence shows that compounds in the mO-NpPyP series with a slightly tilted hard core display greater nematic tendency than those in the nO-PPyP series with a straight hard core.

Keywords:

• synthesis
• pyridine-containing compounds
• liquid crystals
• thermal analysis

Acknowledgement

The financial support of our work by the office of research and development of Fu Jen Catholic University is gratefully acknowledged.