Novel liquid crystalline fluorene and fluorenone MIDA boronates: influence of alkyl vs alkoxy side chains on the mesomorphic properties

ABSTRACT

To obtain novel boron liquid crystals, we successfully combined MIDA boronates with chromophoric fluorene and fluorenone mesogenic units and studied the influence of alkoxy versus alkyl side chains by differential scanning calorimetry (DSC), polarising optical microscopy (POM) and X-ray diffraction (XRD). The fluorenes showed broader temperature ranges of the SmA phase compared to their fluorenone counterparts. By replacing the alkoxy side chains with alkyl side chains, the mesophase ranges could be significantly enlarged and the thermal stability increased.

Graphical abstract

KEYWORDS:

• Fluorene
• fluorenone
• MIDA
• boronates
• X-Ray
• liquid crystals

Acknowledgments

Generous financial support by the Deutsche Forschungsgemeinschaft (grant # LA907/20-1, HBFG and shared instrumentation grant no. INST 41/897-1 FUGG for 700 MHz-NMR and no. INST 41/1136-1 FUGG for HR LC-MS (ESI)), the DAAD PROCOPE project “WELCHYNA”# 57658198, the Ministerium für Wissenschaft, Forschung und Kunst des Landes Baden-Württemberg, Fonds der Chemischen Industrie and the Carl-Schneider-Stiftung Aalen (shared instrumentation grant) is gratefully acknowledged.

Disclosure statement

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

Supplementary data

Supplemental data for this article can be accessed online at https://doi.org/10.1080/02678292.2024.2319626.

Additional information

Funding

This work was supported by the Carl-Schneider-Stiftung [shared instrumentation grant]; Deutsche Forschungsgemeinschaft [La 907/20-1, INST 41/897-1 FUGG, INST 41/1136-1]; German Academic Exchange Service [PHC Procope WELCHYNA #57658198]; Ministerium für Wissenschaft, Forschung und Kunst Baden-Württemberg; Fonds der Chemischen Industrie.