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 builds on our previous work in the field of liquid crystal dimers. In this study, we will investigate relatively uncommon dimers that have a chiral spacer. Our aim is to design a new class of chiral dimers with the chiral moiety positioned in the spacer and examine their mesogenic properties. The novel material will provide a new platform for an in-depth investigation of the relationship between structure and property. This will enable us to study the effect of spacer chirality and parity, as well as the impact of different aromatic mesogenic units on chirality transfer from molecular to multiple levels of structural chirality. Our research will also allow us to correlate chiralities of different origins and discover 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

Dr. Katarina Zlatić

Antonija Ožegović, PhD student

Aleksandra Šimanović, PhD student

Publications:

A. Ožegović, J. Hobbs, R. Mandle, A. Lesac, A. Knežević*" Chiral Cyanobiphenyl Dimers – Significance of the Linking Group for Mesomorphic Properties and Helical Induction" J. Mater. Chem. C, (2024), Advanced Article. doi.org/10.1039/D4TC02597K

A. Ožegović, A. Knežević, J. Novak, S. Šegota, P. Davidson, A. Lesac*, "The Interplay of Spacer Chirality and Parity in Mesogenic Dimers" ChemPhysChem (2024) e202400065. doi.org/10.1002/cphc.202400065 (Hot Topic: Liquid Crystals)

C. Meyer, T. Sergan, V. Sergan, D. Stoenescu, P. Davidson, A. Knežević, . Dokli, A. Lesac, Ivan Dozov "Theoretical model for the Frank elastic moduli in the intercalated SmA_b phase of bent-shaped dimers" Liq. Cryst. (2024), doi.org/10.1080/02678292.2024.2306318

C. Meyer, P. Davidson, T. Sergan, V. Sergan, D. Stoenescu, P. Davidson, A. Knežević, . Dokli, A. Lesac, Ivan Dozov, "Nematic-like elastic coefficients of the SmAb phase" Liq Cryst. 50 (2023), 1; 157-173. doi: 10.1080/02678292.2022.2114026

C. Meyer, P. Davidson, G. R. Luckhurst, I. Dokli, A. Knežević, A. Lesac, D. A. Paterson, R. Walker, J. M.D. Storey, C. T. Imrie, I. Dozov, "Temperature Dependence of the Electroclinic Effect in the Twist-Bend Nematic Phase", Crystals 13 (2023) 465. DOI: 10.3390/cryst13030465

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, 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:

• 29th International Liquid Crystal Conference, Rio de Janeiro, Brazil, 21-26. 07. 2024.

DIMERS WITH CHIRAL SPACER – NOVEL MATERIAL WITH PUZZLING PROPERTIES, Invited lecture presented by Andreja Lesac

CHIRAL LIQUID CRYSTAL DIMERS: SYNTHESIS, MESOMORPHIC PROPERTIES, AND HELICAL DYNAMICS, a poster presentation by Antonija Ožegović

• 9th EFMC International Symposium on Advances in Synthetic and Medicinal Chemistry EFMC-ASMC, Zagreb, Croatia, 3-7. 9. 2023.

ENANTIOSELECTIVE SYNTHESIS OF 3-ARYL-3-HYDROXYPROPANOIC ESTERS AS SUBUNITS FOR CHIRAL LIQUID CRYSTALS, a poster presentation by Irena Dokli

• 22nd European Symposium on Organic Chemistry, Ghent, Belgium, 9-13. 7. 2023.

CHIRAL LIQUID CRYSTALS BEARING 3-ARYL-3-HYDROXYPROPANOIC ESTER SUBUNIT, a poster presentation by Anamarija Knežević

• EuChemS Division of Organic Chemistry – 14^th Young Investigator Workshop (YIW2023), Leuven, Belgija, 7-8. 7. 2023.

FROM LIQUID CRYSTAL DIMERS TO SUPRAMOLECULAR ASSEMBLIES IN WATER WITH A TOUCH OF CHIRALITY, invited lecture by Anamarija knežević

• 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

PhD thesis:

• Antonija Ožegović, THE INFLUENCE OF CHIRALITY OF 3-ARYL-3-HYDROXYPROPANOATE-BASED MOLECULES ON MESOGENIC PROPERTIES OF LIQUID CRYSTALS, 2024., doctoral dissertation, Faculty of Science, University of Zagreb

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: