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Abstract
Novel hydrazide‐modified 4‐methoxyazobenzene derivatives, namely 4‐{n‐[4‐(4‐methoxyphenylazo)phenoxy] alkoxy} benzoic acid hydrazide (D n , n = 3,6,10), were synthesized and characterized. The FTIR spectra of the D n compounds were examined in the range 3500–1000 cm−1 at different temperatures, and two different kinds of hydrogen‐bonded supramolecular structure are proposed. The length as well as the parity of the alkyl spacer in D n play key roles in determining both the supramolecular structure and the liquid crystalline properties. D6 and D10 are monotropic nematic liquid crystals, while D3, is a non‐mesomorphic material. The melting temperatures of D n are higher than those of the 4‐{n‐[4‐(4‐methoxyphenylazo)phenoxy] alkoxy}benzoic ethyl esters (C n , n = 3,6,10) due to the formation of hydrogen bonds.
Acknowledgements
The authors are grateful to the National Science Foundation Committee of China (project No. 29974013, 50373016) and the Excellent Young Teachers Program of MOE, PR China for financial support of this work.