Biphenyls embedded Schiff base-bis esters: self-assembling behaviour, impact of additional aromatic ring and ester linkage and their DFT investigations

ABSTRACT

In the present investigation, two series of biphenyl embedded Schiff base-bis esters alkyl-(E)-4-(((4’-(decyloxy)-[1,1’-biphenyl]-4-yl)methylene)amino)-benzoate, BPK-(2–18) and alkyl-(E)-4-(((4’-((4-(decyloxy)benzoyl)oxy)-[1,1’-biphenyl]-4-yl)-methylene)amino)benzoate, BPEK-(8–18) containing either terminal alkoxy biphenyl core or central biphenyl core have been synthesised and studied for their self-assembling behaviour. The compounds of both series demonstrated enantiotropic liquid crystal properties, displaying typical calamitic mesophases (Smectic A (SmA), Smectic C (SmC)) across a broad temperature range and with high thermal stability. The bimorphic behaviour of new molecules has been investigated by VT-XRD analysis. The density function theory has been done to illustrate the experimental results of the mesomorphic properties of the studied compounds. Several parameters have been calculated such as molecular geometry, dipole moment, polarisability, aspect ratio, etc. The results showed that more planar compounds will attain more packed structures leading to the formation of more ordered smectic phases.

GRAPHICAL ABSTRACT

KEYWORDS:

• Biphenyl Schiff base
• bis-ester
• SmC/SmA mesophase
• VT-XRD analysis
• DFT studies

Acknowledgments

Authors are thankful to Department of Chemistry, The Maharaja Sayajirao University of Baroda, Vadodara for providing laboratory support as well as the necessary instrumental facility. Authors are grateful to DST-FIST programme for NMR and POM facilities.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/02678292.2024.2350044.