Mesogenic behaviour of isomeric bent-core 6-oxoverdazyls: 1,3-vrs 1,5-substitution pattern

ABSTRACT

Two series of isomeric bent-core derivatives of 6-oxoverdazyl, with alkyl and partially fluorinated alkyl chains, were investigated by thermo-optical, powder X-ray diffraction and electron paramagnetic resonance methods in the pure state and binary mixtures. The results revealed that the substitution position of the arms at the verdazyl ring (1,5 vs. 1,3) strongly affects mesogenic behaviour. Steric (torsion and bending angles) and dipolar factors in both isomers are considered.

GRAPHICAL ABSTRACT

KEYWORDS:

• Synthesis
• bent-core
• isomers
• stable radicals
• fluoroalkane
• EPR

Acknowledgements

Technical help of Dr Jadwiga Szydłowska of Warsaw University in obtaining EPR spectra is acknowledged.

Disclosure statement

No potential conflict of interest was reported by the authors.

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Additional information

Funding

This work was supported by the National Science Centre under grants OPUS [2014/13/B/ST5/04525] and PRELUDIUM [2016/21/N/ST5/03068].