One of the most recent examples of spontaneous chirality is the twist-bend nematic phase (N_TB). Unlike the uniaxial nematic phase in which the preferred direction (director) of the molecules is parallel to the main molecular axis (Fig. 1a), the N_TB phase is characterized by a spontaneous twist-bend distortion of the nematic director, which is organized on a conical helix (Fig. 1b). The formation of degenerate helices does not require molecular chirality, instead, it is facilitated by the shape of bent molecules.

The project arises from our previous work in this field of bent-shaped liquid crystal dimers. In continuation of our work on liquid-crystalline dimers, we proceed with the investigation of chiral flexible dimers. The project involves the design of a novel class of chiral dimers with the semi-flexible chiral moiety positioned in the spacer or within the mesogenic unit and the investigation of their mesogenic properties. Targeting bent-shaped molecules, the material represents a new platform for the thorough investigation of the structure-property relation of chiral bent-shaped dimers. It enables correlation between chiralities of different origin as well as the discovery of novel liquid crystalline phases predicted by a recent theory.

Team members

Dr. Andreja Lesac

Dr. Irena Dokli,

Dr. Anamarija Knežević

Dr. Darko Kontrec

Dr. Jurica Novak

Antonija Ožegović, PhD student

Aleksandra Šimanović, PhD student

Publications:

I. Dokli*, A. Ožegović, A. Šimanović, M. Hromin, A. Knežević, A. Višnjevac, A. Lesac*, "Enantioselective Synthesis of 3-Aryl-3-hydroxypropanoic Esters as Subunits for Chiral Liquid Crystals", J. Org. Chem. (2022) DOI: 10.1021/acs.joc.2c01662

C. Meyer, P. Davidson, T. Sergan, V. Sergan, D. Stoenescu, A. Knežević, I. Dokli, A. Lesac and Ivan Dozov "Nematic-like elastic coefficients of the SmA_b phase", Liq. Cryst. (2022), DOI: 10.1080/02678292.2022.2114026

C. Meyer, P. Davidson, D. Constantin, V. Sergan, D. Stoenescu, A. Knežević, I. Dokli, A. Lesac, I. Dozov, "A Fréedericksz-like transition in a biaxial smectic A phase", Phys Rev. X 11 (2021) 031012. DOI: 10.1103/PhysRevX.11.031012

A. Knežević, I. Dokli, J. Novak, D. Kontrec, A. Lesac*, "Fluorinated twist-bend nematogens: the role of intermolecular interaction" Liq. Cryst. 47 (2021) 756-766. DOI: 10.1080/02678292.2020.1817585

Conferences:

• V. SIMPOZIJ SUPRAMOLEKULSKE KEMIJE Supramolecular Chemistry 2022, Zagreb, Hrvatska, 08.12.2022

MOLEKULSKI OBLIK I MIKROSEGREGACIJA – POKRETAČI MEZOGENIH SVOJSTAVA (Molecular shape and microsegregation – initiators of mesogenic properties), an oral presentation by Antonija Ožegović

• 28^th International Liquid Crystal Conference, Lisbon, Portugal, 24-29. 07. 2022.

MESOPHASE DIVERSITY OF BENT-SHAPED DIMERS DRIVEN BY ENANTIOMERIC PURITY,  a poster presentation by Antonija Ožegović and Aleksandra Šimanović

• 6^th Faculty of Science PhD Student Symposium University of Zagreb, 23.-24. 4. 2022.

THE EFFECT OF TERMINAL CHAIN LENGTH ON MESOGENIC PROPERTIES OF BENT-SHAPED DIMERS, a poster presentation by Aleksandra Šimanović

• 6^th Faculty of Science PhD Student Symposium University of Zagreb, 23.-24. 4. 2022.

THE EFFECT OF SPACER LENGTH ON MESOGENIC PROPERTIES OF BENT-SHAPED DIMERS, a poster presentation by Antonija Ožegović

• 27^th Croatian Meeting of Chemists and Chemical Engineers (27HSKIKI), Veli Lošinj, Hrvatska, 5.-8. 10. 2021.

THE EFFECT OF MESOGENIC CORE ON LIQUID-CRYSTALLINE BEHAVIOUR, a poster presentation by Aleksandra Šimanović

• 27^th Croatian Meeting of Chemists and Chemical Engineers (27HSKIKI), Veli Lošinj, Hrvatska, 5.-8. 10. 2021.

INFLUENCE OF THE SPACER LENGTH ON MESOGENIC PROPERTIES OF CHIRAL LIQUID CRYSTAL DIMERS,  a poster presentation by Antonija Ožegović

• 5^th Faculty of Science PhD Student Symposium University of Zagreb, 24.-25. 4. 2021.

 FENIL 3-HIDROKSIPROPIONSKA KISELINA KAO GRAĐEVNI BLOK ZA KIRALNE TEKUĆE KRISTALE SVINUTE GEOMETRIJE, a poster presentation by Antonija Ožegović

• British Liquid Crystal Society Meeting, Aberdeen, 21-24 June 2021.

ARYL-3-HYDROXY PROPIONIC ACID – A VERSATILE CHIRAL BUILDING BLOCK FOR LIQUID CRYSTALS, a poster presentation by Antonija Ožegović

Graduation thesis:

• Marija Čulina, Sinteza spojeva s 3-fenil-3-hidroksipropanskom podjedinicom sa svojstvima tekućih kristala, 2021., diplomski rad, Kemijsko-tehnološki fakultet, Split

• Matija Hromin, Asimetrični prijenos vodika na 3-aril-3- ketoestere - primjena u sintezi kiralnih molekula sa svojstvima tekućih kristala, 2021., diplomski rad, Prirodoslovno-matematički fakultet, Zagreb

Funding: