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Gibb CJ, Hobbs J, Nikolova DI, Raistrick T, Berrow SR, Mertelj A, Osterman N, Sebastián N, Gleeson HF, Mandle RJ. Spontaneous symmetry breaking in polar fluids. Nat Commun 2024; 15:5845. [PMID: 38992039 PMCID: PMC11239904 DOI: 10.1038/s41467-024-50230-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Accepted: 07/03/2024] [Indexed: 07/13/2024] Open
Abstract
Spontaneous symmetry breaking and emergent polar order are each of fundamental importance to a range of scientific disciplines, as well as generating rich phase behaviour in liquid crystals (LCs). Here, we show the union of these phenomena to lead to two previously undiscovered polar liquid states of matter. Both phases have a lamellar structure with an inherent polar ordering of their constituent molecules. The first of these phases is characterised by polar order and a local tilted structure; the tilt direction processes about a helix orthogonal to the layer normal, the period of which is such that we observe selective reflection of light. The second new phase type is anti-ferroelectric, with the constituent molecules aligning orthogonally to the layer normal. This has led us to term the phases the Sm C P H and SmAAF phases, respectively. Further to this, we obtain room temperature ferroelectric nematic (NF) and Sm C P H phases via binary mixture formulation of the novel materials described here with a standard NF compound (DIO), with the resultant materials having melting points (and/or glass transitions) which are significantly below ambient temperature. The new soft matter phase types discovered herein can be considered as electrical analogues of topological structures of magnetic spins in hard matter.
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Affiliation(s)
- Calum J Gibb
- School of Chemistry, University of Leeds, Leeds, UK
| | - Jordan Hobbs
- School of Physics and Astronomy, University of Leeds, Leeds, UK
| | | | | | - Stuart R Berrow
- School of Physics and Astronomy, University of Leeds, Leeds, UK
| | | | - Natan Osterman
- Jožef Stefan Institute, Ljubljana, Slovenia
- University of Ljubljana, Faculty of Mathematics and Physics, Ljubljana, Slovenia
| | | | - Helen F Gleeson
- School of Physics and Astronomy, University of Leeds, Leeds, UK
| | - Richard J Mandle
- School of Chemistry, University of Leeds, Leeds, UK.
- School of Physics and Astronomy, University of Leeds, Leeds, UK.
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2
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Gibb CJ, Majewska M, Pociecha D, Storey JMD, Gorecka E, Imrie CT. Liquid Crystal Dimers and the Twist-Bend Phases: Non-Symmetric Dimers Consisting of Mesogenic Units of Differing Lengths. Chemphyschem 2024; 25:e202300848. [PMID: 38233352 DOI: 10.1002/cphc.202300848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 01/17/2024] [Accepted: 01/17/2024] [Indexed: 01/19/2024]
Abstract
The syntheses and characterisation of the 4-[{[4-({n-[4-(4-cyanophenyl)phenyl]-n-yl}oxy)phenyl]-methylidene}amino]phenyl-4-alkoxybenzoates (CBnOIBeOm) are reported with n=8 and 10 and m=1-10. The two series display fascinating liquid crystal polymorphism. All twenty reported homologues display an enantiotropic nematic (N) phase at high temperature. When the length of the spacer (n) is greater than that of the terminal chain (m), the twist-bend nematic (NTB) phase is observed at temperatures below the N phase. As the length of the terminal chain is increased and extends beyond the length of the spacer up to three smectic phases are observed on cooling the N phase. One of these smectic phases has been assigned as the rare twist-bend smectic C subphase, the SmCTB-α phase. In all the smectic phases, a monolayer packing arrangement is seen, and this is attributed to the anti-parallel associations of the like mesogenic units.
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Affiliation(s)
- Calum J Gibb
- Department of Chemistry, School of Natural and Computing Sciences, University of Aberdeen, Meston Building, Aberdeen, AB24 3UE, UK
| | - Magdalena Majewska
- University of Warsaw, Faculty of Chemistry, ul. Zwirki i Wigury 101, 02-089, Warsaw, Poland
| | - Damian Pociecha
- University of Warsaw, Faculty of Chemistry, ul. Zwirki i Wigury 101, 02-089, Warsaw, Poland
| | - John M D Storey
- Department of Chemistry, School of Natural and Computing Sciences, University of Aberdeen, Meston Building, Aberdeen, AB24 3UE, UK
| | - Ewa Gorecka
- University of Warsaw, Faculty of Chemistry, ul. Zwirki i Wigury 101, 02-089, Warsaw, Poland
| | - Corrie T Imrie
- Department of Chemistry, School of Natural and Computing Sciences, University of Aberdeen, Meston Building, Aberdeen, AB24 3UE, UK
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3
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Kim J, Jeong J. Confinement twists achiral liquid crystals and causes chiral liquid crystals to twist in the opposite handedness: cases in and around sessile droplets. SOFT MATTER 2024; 20:1361-1368. [PMID: 38252544 DOI: 10.1039/d3sm01283b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
We study the chiral symmetry breaking and metastability of confined nematic lyotropic chromonic liquid crystals (LCLCs) with and without chiral dopants. The isotropic-nematic coexistence phase of the LCLC renders two confining geometries: sessile isotropic (I) droplets surrounded by the nematic (N) phase and sessile nematic droplets immersed in the isotropic background. In the achiral system with no dopants, LCLC's elastic anisotropy and topological defects induce a spontaneous twist deformation to lower the energetic penalty of splay deformation, resulting in spiral optical textures under crossed polarizers both in the I-in-N and N-in-I systems. While the achiral system exhibits both handednesses with an equal probability, a small amount of the chiral dopant breaks the balance. Notably, in contrast to the homochiral configuration of a chirally doped LCLC in the bulk, the spiral texture of the disfavored handedness appears with a finite probability both in the I-in-N and N-in-I systems. We propose director field models explaining how chiral symmetry breaking arises by the energetics and the opposite-twist configurations exist as meta-stable structures in the energy landscape. These findings help us create and control chiral structures using confined LCs with large elastic anisotropy.
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Affiliation(s)
- Jungmyung Kim
- Department of Physics, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea.
| | - Joonwoo Jeong
- Department of Physics, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea.
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4
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Gowda A, Pathak SK, Rohaley GAR, Acharjee G, Oprandi A, Williams R, Prévôt ME, Hegmann T. Organic chiral nano- and microfilaments: types, formation, and template applications. MATERIALS HORIZONS 2024; 11:316-340. [PMID: 37921354 DOI: 10.1039/d3mh01390a] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2023]
Abstract
Organic chiral nanofilaments are part of an important class of nanoscale chiral materials that has recently been receiving significant attention largely due to their potential use in applications such as optics, photonics, metameterials, and potentially a range of medical as well as sensing applications. This review will focus on key examples of the formation of such nano- and micro-filaments based on carbon nanofibers, polymers, synthetic oligo- and polypeptides, self-assembled organic molecules, and one prominent class of liquid crystals. The most critical aspects discussed here are the underlying driving forces for chiral filament formation, potentially answering why specific sizes and shapes are formed, what molecular design strategies are working equally well or rather differently among these materials classes, and what uses and applications are driving research in this fascinating field of materials science.
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Affiliation(s)
- Ashwathanarayana Gowda
- Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, OH 44242, USA.
| | - Suraj Kumar Pathak
- Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, OH 44242, USA.
| | - Grace A R Rohaley
- Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, OH 44242, USA.
- Materials Science Graduate Program, Kent State University, Kent, OH 44242, USA
| | - Gourab Acharjee
- Department of Chemistry and Biochemistry, Kent State University, Kent, OH 44242, USA
| | - Andrea Oprandi
- Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, OH 44242, USA.
- Materials Science Graduate Program, Kent State University, Kent, OH 44242, USA
| | - Ryan Williams
- Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, OH 44242, USA.
- Materials Science Graduate Program, Kent State University, Kent, OH 44242, USA
| | - Marianne E Prévôt
- Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, OH 44242, USA.
- Department of Chemistry and Biochemistry, Kent State University, Kent, OH 44242, USA
| | - Torsten Hegmann
- Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, OH 44242, USA.
- Brain Health Research Institute, Kent State University, Kent, OH 44242, USA
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5
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Podoliak N, Salamon P, Lejček L, Kužel P, Novotná V. Undulations of Smectic A Layers in Achiral Liquid Crystals Manifested as Stripe Textures. PHYSICAL REVIEW LETTERS 2023; 131:228101. [PMID: 38101389 DOI: 10.1103/physrevlett.131.228101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 10/24/2023] [Indexed: 12/17/2023]
Abstract
Self-assembly of organic molecules represents a fascinating playground to create various liquid crystalline nanostructures. In this Letter, we study layer undulations on micrometer scale in smectic A phases for achiral compounds, experimentally demonstrated as regular stripe patterns induced by thermal treatment. Undulations, including their anharmonic properties, are evaluated by means of polarimetric imaging and light diffraction experiments in cells with various thicknesses. The key role in stripe formation is played by high negative values of the thermal expansion coefficient.
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Affiliation(s)
- Natalia Podoliak
- Institute of Physics of the Czech Academy of Sciences, Na Slovance 2, CZ-182 00 Prague 8, Czech Republic
| | - Peter Salamon
- Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, P.O. Box 49, Budapest H-1525, Budapest, Hungary
| | - Lubor Lejček
- Institute of Physics of the Czech Academy of Sciences, Na Slovance 2, CZ-182 00 Prague 8, Czech Republic
| | - Petr Kužel
- Institute of Physics of the Czech Academy of Sciences, Na Slovance 2, CZ-182 00 Prague 8, Czech Republic
| | - Vladimíra Novotná
- Institute of Physics of the Czech Academy of Sciences, Na Slovance 2, CZ-182 00 Prague 8, Czech Republic
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6
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Lepori M, Schmid S, Barham JP. Photoredox catalysis harvesting multiple photon or electrochemical energies. Beilstein J Org Chem 2023; 19:1055-1145. [PMID: 37533877 PMCID: PMC10390843 DOI: 10.3762/bjoc.19.81] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Accepted: 07/07/2023] [Indexed: 08/04/2023] Open
Abstract
Photoredox catalysis (PRC) is a cutting-edge frontier for single electron-transfer (SET) reactions, enabling the generation of reactive intermediates for both oxidative and reductive processes via photon activation of a catalyst. Although this represents a significant step towards chemoselective and, more generally, sustainable chemistry, its efficacy is limited by the energy of visible light photons. Nowadays, excellent alternative conditions are available to overcome these limitations, harvesting two different but correlated concepts: the use of multi-photon processes such as consecutive photoinduced electron transfer (conPET) and the combination of photo- and electrochemistry in synthetic photoelectrochemistry (PEC). Herein, we review the most recent contributions to these fields in both oxidative and reductive activations of organic functional groups. New opportunities for organic chemists are captured, such as selective reactions employing super-oxidants and super-reductants to engage unactivated chemical feedstocks, and scalability up to gram scales in continuous flow. This review provides comparisons between the two techniques (multi-photon photoredox catalysis and PEC) to help the reader to fully understand their similarities, differences and potential applications and to therefore choose which method is the most appropriate for a given reaction, scale and purpose of a project.
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Affiliation(s)
- Mattia Lepori
- Fakultät für Chemie und Pharmazie, Universität Regensburg, Universitatsstraße 31, 93040 Regensburg, Germany
| | - Simon Schmid
- Fakultät für Chemie und Pharmazie, Universität Regensburg, Universitatsstraße 31, 93040 Regensburg, Germany
| | - Joshua P Barham
- Fakultät für Chemie und Pharmazie, Universität Regensburg, Universitatsstraße 31, 93040 Regensburg, Germany
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7
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Choudhary S, Gayyur, Kant R, Ghosh N. Leveraging Zn(II) Catalyst: Synthesis of Amidoquinolines via (3 + 3) Heteroannulation of Aromatic Amines and Ynamides. J Org Chem 2023. [PMID: 37466147 DOI: 10.1021/acs.joc.3c00568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/20/2023]
Abstract
Herein, we present a Zn(II)-catalyzed (3 + 3) heteroannulation reaction between aromatic amines and 1,3-diynamides for the synthesis of amidoquinolines. A large number of aromatic amines are well tolerated, furnishing quinoline derivatives in up to excellent yield. Notably, various reactive functional groups have survived under the optimal reaction conditions, highlighting the mildness of the developed protocol. In addition, amines derived from bioactive molecules show modest reactivity.
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Affiliation(s)
- Shivani Choudhary
- Medicinal & Process Chemistry Division, CSIR-Central Drug Research Institute, Lucknow 226031, U.P., India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Gayyur
- Medicinal & Process Chemistry Division, CSIR-Central Drug Research Institute, Lucknow 226031, U.P., India
| | - Ruchir Kant
- Molecular and Structural Biology Division, CSIR-Central Drug Research Institute, Lucknow 226031, India
| | - Nayan Ghosh
- Medicinal & Process Chemistry Division, CSIR-Central Drug Research Institute, Lucknow 226031, U.P., India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
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8
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Sewring T, Trulsson M. Ground State Configurations and Metastable Phases of Charged Linear Rods. ACS OMEGA 2023; 8:6040-6051. [PMID: 36816665 PMCID: PMC9933468 DOI: 10.1021/acsomega.2c08060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Accepted: 01/24/2023] [Indexed: 06/18/2023]
Abstract
This computational study investigates the energy minimum, that is, ground state, of suspensions of monodisperse (single-component) charged linear rods at various densities and screening lengths. We find that closed-packed unidirectional configurations have the lowest energies for all studied cases. We further specify the lattice parameters for these crystalline structures. In addition, we identify a few metastable phases, including heliconical structures. These metastable heliconical phases are composed of hexagonal smectic C layers with particle orientations forming a conical helicoid with a short pitch of three layers. We evidence this by zero-temperature Monte Carlo simulations starting from an energy-minimized hexagonal cholesteric configuration, which rapidly transforms to a heliconical phase. Furthermore, this heliconical phase is remarkably stable even at finite temperatures and melts to a disordered phase at high temperatures. Finally, we conduct simulations at room temperature and conditions typical for cellulose nanocrystal suspensions to study the onset of nematic order and compare our results to available experimental data. Our findings suggest that electrostatics play an important role in the isotropic/anisotropic transition for dense suspensions of charged rods.
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Affiliation(s)
- Tor Sewring
- Theoretical
Chemistry, Lund University, 221 00Lund, Sweden
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9
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Eremin A, Murad A, Alaasar M. Shear-induced birefringence in an optically isotropic cubic liquid crystalline phase. SOFT MATTER 2022; 18:8315-8319. [PMID: 36300301 DOI: 10.1039/d2sm01148d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
We report an unusually strong flow-induced birefringence in an optically isotropic cubic phase occurring below the isotropic chiral conglomerate phase formed by a low-molecular-weight polycatenar mesogen. The transition into the birefringent state occurs thresholdless and the induced birefringence is comparable with that observed in polymeric systems. We suggest that the flow-induced deformation of the cubic structure is responsible for the strong rheo-optical response.
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Affiliation(s)
- Alexey Eremin
- Department of Nonlinear Phenomena, Institute for Physics Otto von Guericke University Magdeburg, Magdeburg, Germany.
| | - Ahmad Murad
- Department of Nonlinear Phenomena, Institute for Physics Otto von Guericke University Magdeburg, Magdeburg, Germany.
| | - Mohamed Alaasar
- Department of Chemistry, Martin-Luther University Halle-Wittenberg, 06120 Halle (Saale), Germany.
- Department of Chemistry, Cairo University, Giza, Egypt.
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10
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Grabovac T, Gorecka E, Zhu C, Pociecha D, Vaupotič N. Unmasking the structure of a chiral cubic thermotropic liquid crystal phase by a combination of soft and tender resonant X-ray scattering. SOFT MATTER 2022; 18:8194-8200. [PMID: 36269084 DOI: 10.1039/d2sm01030e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
A resonant X-ray scattering response for two structural models of a chiral cubic phase with a giant unit cell, one composed of a continuous grid and micelles and the other with three continuous grids, is studied theoretically and compared to experimental measurements. For both structural models resonant enhancement of all the symmetry-allowed diffraction peaks is predicted, as well as the existance of several symmetry forbidden peaks (pure resonant peaks). Experimental measurements were performed at the carbon and sulphur absorption edge. Only one pure resonant peak was observed, which is predicted by both models. Two low-angle symmetry allowed peaks, not observed in non-resonant scattering, were resonantly enhanced and their intensity angular dependence can distinguish between the two structural models.
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Affiliation(s)
- Timon Grabovac
- Department of Physics, Faculty of Natural Sciences and Mathematics, University of Maribor, Koroška 160, 2000 Maribor, Slovenia.
| | - Ewa Gorecka
- Faculty of Chemistry, University of Warsaw, Żwirki i Wigury 101, 02-089 Warsaw, Poland.
| | - Chenhui Zhu
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Damian Pociecha
- Faculty of Chemistry, University of Warsaw, Żwirki i Wigury 101, 02-089 Warsaw, Poland.
| | - Nataša Vaupotič
- Department of Physics, Faculty of Natural Sciences and Mathematics, University of Maribor, Koroška 160, 2000 Maribor, Slovenia.
- Jozef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia
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11
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A Severe Hurricane Increases Carbon Dioxide and Methane Fluxes and Triples Nitrous Oxide Emissions in a Tropical Forest. Ecosystems 2022. [DOI: 10.1007/s10021-022-00794-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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12
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Kubala P, Tomczyk W, Cieśla M. In silico study of liquid crystalline phases formed by bent-shaped molecules with excluded volume type interactions. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.120156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
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13
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Alshammari AF, Pociecha D, Walker R, Storey JMD, Gorecka E, Imrie CT. New patterns of twist-bend liquid crystal phase behaviour: the synthesis and characterisation of the 1-(4-cyanobiphenyl-4'-yl)-10-(4-alkylaniline-benzylidene-4'-oxy)decanes (CB10O· m). SOFT MATTER 2022; 18:4679-4688. [PMID: 35678154 DOI: 10.1039/d2sm00162d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The synthesis and characterisation of the 1-(4-cyanobiphenyl-4'-yl)-10-(4-alkylanilinebenzylidene-4'-oxy)decanes (CB10O·m) are reported. This series shows a rich liquid crystal polymorphism including twist-bend nematic and smectic phases. All the homologues reported exhibit an enantiotropic conventional nematic phase. For the homologues with m ≤ 10, the local packing in the nematic phases and the layer spacing in the smectic phases indicates an intercalated arrangement of the molecules. An intercalated smectic CA phase is observed if m/11 ≈ 0.5. Either side of this condition, the twist-bend nematic phase is observed, a novel pattern of behaviour for a series on increasing a terminal chain length. For longer chain lengths, m = 12, 14, 16 and 18, two twist-bend smectic C (SmCTB) phases are observed, and the packing of the molecules is now of a bilayer-type. The higher temperature variant is termed SmCTB-SH in which SH (single helix) refers to the presence of a short, distorted clock-type helix. In the lower temperature SmCTB-DH phase, an additional longer helix is superimposed on the short one, and DH denotes double helix.
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Affiliation(s)
- Ahlam F Alshammari
- Department of Chemistry, School of Natural and Computing Sciences, University of Aberdeen, AB24 3UE Scotland, UK.
| | - Damian Pociecha
- University of Warsaw, Faculty of Chemistry, ul. Zwirki i Wigury 101, 02-089 ˙ Warsaw, Poland
| | - Rebecca Walker
- Department of Chemistry, School of Natural and Computing Sciences, University of Aberdeen, AB24 3UE Scotland, UK.
| | - John M D Storey
- Department of Chemistry, School of Natural and Computing Sciences, University of Aberdeen, AB24 3UE Scotland, UK.
| | - Ewa Gorecka
- University of Warsaw, Faculty of Chemistry, ul. Zwirki i Wigury 101, 02-089 ˙ Warsaw, Poland
| | - Corrie T Imrie
- Department of Chemistry, School of Natural and Computing Sciences, University of Aberdeen, AB24 3UE Scotland, UK.
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14
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Wide Nematogenic Azomethine/Ester Liquid Crystals Based on New Biphenyl Derivatives: Mesomorphic and Computational Studies. Molecules 2022; 27:molecules27134150. [PMID: 35807398 PMCID: PMC9268434 DOI: 10.3390/molecules27134150] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 06/18/2022] [Accepted: 06/25/2022] [Indexed: 02/04/2023] Open
Abstract
The thermal stability and mesomorphic behavior of a new biphenyl azomethine liquid crystal homologues series, (E)-4-(([1,1′-biphenyl]-4-ylmethylene)amino)phenyl 4-(alkoxy)benzoate, In, were investigated. The chemical structures of the synthesized compounds were characterized using FT-IR, NMR, and elemental analyses. Differential scanning calorimetry (DSC) and polarized optical microscopy were employed to evaluate the mesomorphic characteristics of the designed homologues. The examined homologues possessed high thermal stability and broad nematogenic temperature ranges. Furthermore, the homologues were covered by enantiotropic nematic phases. The experimental measurements of the mesomorphic behavior were substantiated by computational studies using the density functional theory (DFT) approach. The reactivity parameters, dipole moments, and polarizability of the studied molecules are discussed. The theoretical calculations demonstrated that as the chain length increased, the polarizability of the studied series increased; while it did not significantly affect the HOMO–LUMO energy gap and other reactivity descriptors, the biphenyl moiety had an essential impact on the stability of the possible geometries and their thermal as well as physical parameters.
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15
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Park KS, Xue Z, Patel BB, An H, Kwok JJ, Kafle P, Chen Q, Shukla D, Diao Y. Chiral emergence in multistep hierarchical assembly of achiral conjugated polymers. Nat Commun 2022; 13:2738. [PMID: 35585050 PMCID: PMC9117306 DOI: 10.1038/s41467-022-30420-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 04/27/2022] [Indexed: 11/09/2022] Open
Abstract
Intimately connected to the rule of life, chirality remains a long-time fascination in biology, chemistry, physics and materials science. Chiral structures, e.g., nucleic acid and cholesteric phase developed from chiral molecules are common in nature and synthetic soft materials. While it was recently discovered that achiral but bent-core mesogens can also form chiral helices, the assembly of chiral microstructures from achiral polymers has rarely been explored. Here, we reveal chiral emergence from achiral conjugated polymers, in which hierarchical helical structures are developed through a multistep assembly pathway. Upon increasing concentration beyond a threshold volume fraction, dispersed polymer nanofibers form lyotropic liquid crystalline (LC) mesophases with complex, chiral morphologies. Combining imaging, X-ray and spectroscopy techniques with molecular simulations, we demonstrate that this structural evolution arises from torsional polymer molecules which induce multiscale helical assembly, progressing from nano- to micron scale helical structures as the solution concentration increases. This study unveils a previously unknown complex state of matter for conjugated polymers that can pave way to a field of chiral (opto)electronics. We anticipate that hierarchical chiral helical structures can profoundly impact how conjugated polymers interact with light, transport charges, and transduce signals from biomolecular interactions and even give rise to properties unimagined before.
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Affiliation(s)
- Kyung Sun Park
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, 600 S. Mathews Ave., Urbana, IL, 61801, USA
| | - Zhengyuan Xue
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, 600 S. Mathews Ave., Urbana, IL, 61801, USA
| | - Bijal B Patel
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, 600 S. Mathews Ave., Urbana, IL, 61801, USA
| | - Hyosung An
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, 1304 W. Green St., Urbana, IL, 61801, USA
| | - Justin J Kwok
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, 1304 W. Green St., Urbana, IL, 61801, USA
| | - Prapti Kafle
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, 600 S. Mathews Ave., Urbana, IL, 61801, USA
| | - Qian Chen
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, 1304 W. Green St., Urbana, IL, 61801, USA
| | - Diwakar Shukla
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, 600 S. Mathews Ave., Urbana, IL, 61801, USA
| | - Ying Diao
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, 600 S. Mathews Ave., Urbana, IL, 61801, USA.
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, 1304 W. Green St., Urbana, IL, 61801, USA.
- Beckman Institute, Molecular Science and Engineering, University of Illinois at Urbana-Champaign, 405 N. Mathews Ave., Urbana, IL, 61801, USA.
- Department of Chemistry, University of Illinois at Urbana-Champaign, 505 S. Mathews Ave., Urbana, IL, 61801, USA.
- Materials Research Laboratory, The Grainger College of Engineering, University of Illinois at Urbana-Champaign, 104 S. Goodwin Ave., Urbana, IL, 61801, USA.
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Majewska MM, Forsyth E, Pociecha D, Wang C, Storey JMD, Imrie CT, Gorecka E. Controlling spontaneous chirality in achiral materials: liquid crystal oligomers and the heliconical twist-bend nematic phase. Chem Commun (Camb) 2022; 58:5285-5288. [PMID: 35398878 DOI: 10.1039/d1cc07012f] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Liquid crystal oligomers, namely dimers, trimers and tetramers, consisting of cyanobiphenyl and benzylideneaniline-based mesogenic units connected by either linear or bent alkoxy or alkyl spacers are reported. These materials, although built from achiral molecules, show the spontaneously chiral heliconical twist-bend nematic (NTB) phase. We report the relationships between the shape of the oligomer, and the NTB phase stability, the temperature dependence of the helical pitch length and tilt angle, birefringence, and elastic constants.
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Affiliation(s)
- M M Majewska
- Faculty of Chemistry, University of Warsaw, ul. Zwirki i Wigury 101, 02-089 Warsaw, Poland.
| | - E Forsyth
- Department of Chemistry, School of Natural and Computing Sciences, University of Aberdeen, Meston Building, Aberdeen AB24 3UE, UK
| | - D Pociecha
- Faculty of Chemistry, University of Warsaw, ul. Zwirki i Wigury 101, 02-089 Warsaw, Poland.
| | - C Wang
- Advanced Light Source, LBNL, Berkeley, CA 94720, USA
| | - J M D Storey
- Department of Chemistry, School of Natural and Computing Sciences, University of Aberdeen, Meston Building, Aberdeen AB24 3UE, UK
| | - C T Imrie
- Department of Chemistry, School of Natural and Computing Sciences, University of Aberdeen, Meston Building, Aberdeen AB24 3UE, UK
| | - E Gorecka
- Faculty of Chemistry, University of Warsaw, ul. Zwirki i Wigury 101, 02-089 Warsaw, Poland.
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17
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A Ten-Year Perspective on Twist-Bend Nematic Materials. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27092689. [PMID: 35566040 PMCID: PMC9102178 DOI: 10.3390/molecules27092689] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 04/20/2022] [Accepted: 04/20/2022] [Indexed: 11/16/2022]
Abstract
The discovery of the twist-bend nematic phase (NTB) is a milestone within the field of liquid crystals. The NTB phase has a helical structure, with a repeat length of a few nanometres, and is therefore chiral, even when formed by achiral molecules. The discovery and rush to understand the rich physics of the NTB phase has provided a fresh impetus to the design and characterisation of dimeric and oligomeric liquid crystalline materials. Now, ten years after the discovery of the NTB phase, we review developments in this area, focusing on how molecular features relate to the incidence of this phase, noting the progression from simple symmetrical dimeric materials towards complex oligomers, non-covalently bonded supramolecular systems.
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18
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Yu G, Wilson MR. All-atom simulations of bent liquid crystal dimers: the twist-bend nematic phase and insights into conformational chirality. SOFT MATTER 2022; 18:3087-3096. [PMID: 35377382 DOI: 10.1039/d2sm00291d] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The liquid crystal dimer 1,7-bis-4-(4'-cyanobiphenyl)heptane (CB7CB) is known to exhibit a nematic-nematic phase transition, with the lower temperature phase identified as the twist-bend nematic (NTB) phase. Despite the achiral nature of the mesogen, the NTB phase demonstrates emergent chirality through the spontaneous formation of a helical structure. We present extensive molecular dynamics simulations of CB7CB using an all-atom force field. The NTB phase is observed in this model and, upon heating, shows phase transitions into the nematic (N) and isotropic phases. The simulated NTB phase returns a pitch of 8.35 nm and a conical tilt angle of 29°. Analysis of the bend angle between the mesogenic units reveals an average angle of 127°, which is invariant to the simulated phase. We have calculated distributions of the chirality order parameter, χ, for the ensemble of conformers in the NTB and N phases. These distributions elucidate that CB7CB is statistically achiral but can adopt chiral conformers with no preference for a specific handedness. Furthermore, there is no change in the extent of conformational chirality between the NTB and N phases. Using single-molecule stochastic dynamics simulations in the gas phase, we study the dimer series CBnCB (where n = 6, 7, 8 or 9) and CBX(CH2)5YCB (where X/Y = CH2, O or S) in terms of the bend angle and conformational chirality. We confirm that the bent molecular shape determines the ability of a dimer to exhibit the NTB phase rather than its potential to assume chiral conformers; as |χ|max increases with the spacer length, but the even-membered dimers have a linear shape in contrast to the bent nature of dimers with spacers of odd parity. For CBX(CH2)5YCB, it is found that |χ|max increases as the bend angle of the dimer decreases, while the flexibility of the dimers remains unchanged through the series.
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Affiliation(s)
- Gary Yu
- Department of Chemistry, Durham University, Lower Mountjoy, Stockton Road, Durham, UK.
| | - Mark Richard Wilson
- Department of Chemistry, Durham University, Lower Mountjoy, Stockton Road, Durham, UK.
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19
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Alaasar M, Cai X, Kraus F, Giese M, Liu F, Tschierske C. Controlling ambidextrous mirror symmetry breaking in photosensitive supramolecular polycatenars by alkyl-chain engineering. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.118597] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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20
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Alamro FS, Al-Kadhi NS, Gomha SM, Popoola SA, Khushaim MS, Alhaddad OA, Ahmed HA. Experimental and Theoretical Investigations of Three-Ring Ester/Azomethine Materials. MATERIALS (BASEL, SWITZERLAND) 2022; 15:2312. [PMID: 35329764 PMCID: PMC8949326 DOI: 10.3390/ma15062312] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 03/10/2022] [Accepted: 03/18/2022] [Indexed: 12/26/2022]
Abstract
New three-ring ester/azomethine homologues series, (E)-4-((4-hydroxybenzylidene)amino)phenyl 4-(alkoxy)benzoate In, were prepared and their properties were investigated experimentally and theoretically. FT-IR, NMR, and elemental analyses were used to confirm the chemical structures of the synthesized compounds. The mesomorphic activities of the planned homologues were evaluated using differential scanning calorimetry (DSC) and polarized optical microscopy. All of the homologous examined were found to have non-mesomorphic properties. Theoretical calculations using the density functional theory (DFT) were used to validate the experimental data and determine the most stable conformation of the synthesized compounds. All calculated conformers' thermal properties, dipole moments, and polarizability were discussed. The results show that the terminal alkoxy chain length affects the thermal parameters of the conformers. The correlations between these parameters' values and the conformer type were demonstrated. The base component was expected to be in two conformers according to the orientation of the N atom of imine-linkage. DFT calculations revealed the more probable of the two possible conformers, and the incorporation of the alkoxy terminal chain in one position affect its geometrical and mesomerphic characteristics.
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Affiliation(s)
- Fowzia S. Alamro
- Department of Chemistry, College of Science, Princess Nourah bint Abdulrahman University, P.O. Box 84428, Riyadh 11671, Saudi Arabia; (F.S.A.); (N.S.A.-K.)
| | - Nada S. Al-Kadhi
- Department of Chemistry, College of Science, Princess Nourah bint Abdulrahman University, P.O. Box 84428, Riyadh 11671, Saudi Arabia; (F.S.A.); (N.S.A.-K.)
| | - Sobhi M. Gomha
- Chemistry Department, Faculty of Science, Islamic University of Madinah, Madinah 42351, Saudi Arabia;
- Department of Chemistry, Faculty of Science, Cairo University, Cairo 12613, Egypt
| | - Saheed A. Popoola
- Chemistry Department, Faculty of Science, Islamic University of Madinah, Madinah 42351, Saudi Arabia;
| | - Muna S. Khushaim
- Department of Physics, Faculty of Science, Taibah University, P.O. Box 30002, Al-Madina 41447, Saudi Arabia;
- Nanotechonolgy Center, Taibah University, P.O. Box 30002, Al-Madina 41447, Saudi Arabia
| | - Omaima A. Alhaddad
- Chemistry Department, College of Sciences, Taibah University, Madina Monawara 30002, Saudi Arabia;
| | - Hoda A. Ahmed
- Department of Chemistry, Faculty of Science, Cairo University, Cairo 12613, Egypt
- Chemistry Department, College of Sciences, Taibah University, Yanbu 30799, Saudi Arabia
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21
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New Self-Organizing Optical Materials and Induced Polymorphic Phases of Their Mixtures Targeted for Energy Investigations. Polymers (Basel) 2022; 14:polym14030456. [PMID: 35160446 PMCID: PMC8838461 DOI: 10.3390/polym14030456] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 01/18/2022] [Accepted: 01/20/2022] [Indexed: 02/07/2023] Open
Abstract
Herein, a new homologues series of fluorinated liquid crystal compounds, In, 4-(((4-fluorophenyl)imino)methyl)-2-methoxyphenyl 4-alkoxybenzoate were synthesized and its mesomorphic properties were investigated both experimentally and theoretically. The synthesized compounds were characterized by elemental analyzer, NMR, and FT-IR spectroscopy to deduce the molecular structures. The differential scanning calorimetry was employed to examine mesophase transitions whereas the polarized optical microscopy was used to identify the mesophases. The obtained results revealed that the purely nematic phase observed in all terminal side chains. All homologues showed to possess monotropic nematic mesophases except the derivative I8 exhibits enantiotropic property. The optimized geometrical structures of the present designed groups have been derived theoretically. The experimental data was explained using density functional theory computations. The estimated values of dipole moment, polarizability, thermal energy, and molecule electrostatic potential demonstrated that the mesophase stability and type could be illustrated. Binary phase diagram was constructed and addressed in terms of the mesomorphic temperature range and obtained polymorphic phases. It was found that incorporation of the terminal F-atom and lateral CH3O group influence both conformation and steric effect in pure and mixed states. The absorption and fluorescence emission spectra of fabricated films were recorded to elucidate the impact of terminal side chain on photophysical properties of synthesized liquid crystal. It was noted that the increase of terminal side chain length lead to reduction of optical band gap, whereas charge carrier lifetime increases.
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22
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Li X, Buda F, de Groot HJ, Sevink GJA. The role of chirality and plastic crystallinity in the optical and mechanical properties of chlorosomes. iScience 2022; 25:103618. [PMID: 35005556 PMCID: PMC8719020 DOI: 10.1016/j.isci.2021.103618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 11/15/2021] [Accepted: 12/08/2021] [Indexed: 11/26/2022] Open
Abstract
The most efficient light-harvesting antennae found in nature, chlorosomes, are molecular tubular aggregates (TMAs) assembled by pigments without protein scaffolds. Here, we discuss a classification of chlorosomes as a unique tubular plastic crystal and we attribute the robust energy transfer in chlorosomes to this unique nature. To systematically study the role of supramolecular tube chirality by molecular simulation, a role that has remained unresolved, we share a protocol for generating realistic tubes at atomic resolution. We find that both the optical and the mechanical behavior are strongly dependent on chirality. The optical-chirality relation enables a direct interpretation of experimental spectra in terms of overall tube chirality. The mechanical response shows that the overall chirality regulates the hardness of the tube and provides a new characteristic for relating chlorosomes to distinct chirality. Our protocol also applies to other TMA systems and will inspire other systematic studies beyond lattice models. Classifies chlorosomes in terms of a tubular plastic crystal phase Clarifies the unique strategy of chlorosomes for harvesting and transporting energy Presents a protocol for building atom-resolved helical tube structures Maps tube chirality directly to measurable optical and mechanical responses
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Affiliation(s)
- Xinmeng Li
- Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2300 RA Leiden, South Holland, the Netherlands
- Department of Chemistry and Hylleraas Centre for Quantum Molecular Sciences, P.O.Box 1033, Blindern, Oslo, 0315 Oslo, Norway
- Corresponding author
| | - Francesco Buda
- Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2300 RA Leiden, South Holland, the Netherlands
| | - Huub J.M. de Groot
- Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2300 RA Leiden, South Holland, the Netherlands
| | - G. J. Agur Sevink
- Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2300 RA Leiden, South Holland, the Netherlands
- Corresponding author
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23
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Pawlak M, Bagiński M, Llombart P, Beutel D, Gonzalez-Rubio G, Gorecka E, Rockstuhl C, Mieczkowski J, Pociecha D, Lewandowski W. Tuneable helices of plasmonic nanoparticles using liquid crystal templates: molecular dynamics investigation of an unusual odd-even effect in liquid crystalline dimers. Chem Commun (Camb) 2022; 58:7364-7367. [DOI: 10.1039/d2cc00560c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Liquid crystalline (LC) dimers formed helical nanofilaments depending on the parity of the alkyl linker, revealing an unusual odd-even effect. Molecular dynamics simulations were used to investigate the observed tendency....
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24
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Helical phases assembled from achiral molecules: Twist-bend nematic and helical filamentary B4 phases formed by mesogenic dimers. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2021.118180] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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25
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All Structures Great and Small: Nanoscale Modulations in Nematic Liquid Crystals. NANOMATERIALS 2021; 12:nano12010093. [PMID: 35010040 PMCID: PMC8746648 DOI: 10.3390/nano12010093] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 12/25/2021] [Accepted: 12/27/2021] [Indexed: 02/06/2023]
Abstract
The nature of the nanoscale structural organization in modulated nematic phases formed by molecules having a nonlinear molecular architecture is a central issue in contemporary liquid crystal research. Nevertheless, the elucidation of the molecular organization is incomplete and poorly understood. One attempt to explain nanoscale phenomena merely “shrinks down” established macroscopic continuum elasticity modeling. That explanation initially (and mistakenly) identified the low temperature nematic phase (NX), first observed in symmetric mesogenic dimers of the CB-n-CB series with an odd number of methylene spacers (n), as a twist–bend nematic (NTB). We show that the NX is unrelated to any of the elastic deformations (bend, splay, twist) stipulated by the continuum elasticity theory of nematics. Results from molecular theory and computer simulations are used to illuminate the local symmetry and physical origins of the nanoscale modulations in the NX phase, a spontaneously chiral and locally polar nematic. We emphasize and contrast the differences between the NX and theoretically conceivable nematics exhibiting spontaneous modulations of the elastic modes by presenting a coherent formulation of one-dimensionally modulated nematics based on the Frank–Oseen elasticity theory. The conditions for the appearance of nematic phases presenting true elastic modulations of the twist–bend, splay–bend, etc., combinations are discussed and shown to clearly exclude identifications with the nanoscale-modulated nematics observed experimentally, e.g., the NX phase. The latter modulation derives from packing constraints associated with nonlinear molecules—a chiral, locally-polar structural organization indicative of a new type of nematic phase.
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26
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Smekhova A, Novotná V, Fekete L, Abrudan R, Fondell M, Hamplová V, Ostrovskii BI. Ultra-short helix pitch and spiral ordering in cholesteric liquid crystal revealed by resonant soft X-ray scattering. SOFT MATTER 2021; 18:89-96. [PMID: 34870645 DOI: 10.1039/d1sm01543e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The spontaneous formation of chiral structures offers a variety of liquid crystals (LC) phases that could be further tailored for practical applications. In our work, the characteristic features of spiral ordering in the cholesteric phase of EZL10/10 LC were evaluated. To disclose resonant reflections related to a nanoscale helix pitch, resonant soft X-ray scattering at the carbon K edge was employed. The angular positions of the observed element-specific scattering peaks reveal a half-pitch of the spiral ordering p/2 ≈ 52 nm indicating the full pitch of about 104 nm at room temperature. The broadening of the peaks points to a presence of coherently scattering finite-size domains formed by cholesteric spirals with lengths of about five pitches. No scattering peaks were detectable in the EZL10/10 isotropic phase at higher temperatures. The characteristic lengths extracted from the resonant soft X-ray scattering experiment agree well with the periodicity of the surface "fingerprint" pattern observed in the EZL10/10 cholesteric phase by means of atomic force microscopy. The stability of LC molecules under the incident beam was proven by X-ray absorption spectroscopy in transmission geometry.
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Affiliation(s)
- Alevtina Smekhova
- Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin 12489, Germany.
| | - Vladimíra Novotná
- Institute of Physics of the Czech Academy of Sciences, Prague 8, Czech Republic
| | - Ladislav Fekete
- Institute of Physics of the Czech Academy of Sciences, Prague 8, Czech Republic
| | - Radu Abrudan
- Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin 12489, Germany.
| | - Mattis Fondell
- Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin 12489, Germany.
| | - Věra Hamplová
- Institute of Physics of the Czech Academy of Sciences, Prague 8, Czech Republic
| | - Boris I Ostrovskii
- Federal Scientific Research Center "Crystallography and photonics", Russian Academy of Sciences, 119333 Moscow, Russia.
- Institute of Solid State Physics, Russian Academy of Sciences, 142432 Chernogolovka, Russia
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27
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Photo-driven effects in twist-bend nematic phases: Dynamic and memory response of liquid crystalline dimers. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.117680] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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28
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Pociecha D, Vaupotič N, Majewska M, Cruickshank E, Walker R, Storey JMD, Imrie CT, Wang C, Gorecka E. Photonic Bandgap in Achiral Liquid Crystals-A Twist on a Twist. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2103288. [PMID: 34396593 DOI: 10.1002/adma.202103288] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 06/22/2021] [Indexed: 06/13/2023]
Abstract
Achiral mesogenic molecules are shown to be able to spontaneously assemble into liquid crystalline smectic phases having either simple or double-helical structures. At the transition between these phases, the double-helical structure unwinds. As a consequence, in some temperature range, the pitch of the helix becomes comparable to the wavelength of visible light and the selective reflection of light in the visible range is observed. The photonic bandgap phenomenon is reported for achiral liquid crystals.
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Affiliation(s)
- Damian Pociecha
- Faculty of Chemistry, University of Warsaw, Zwirki i Wigury 101, Warsaw, 02-089, Poland
| | - Nataša Vaupotič
- Department of Physics, Faculty of Natural Sciences and Mathematics, University of Maribor, Koroška 160, Maribor, 2000, Slovenia
- Jozef Stefan Institute, Jamova 39, Ljubljana, 1000, Slovenia
| | - Magdalena Majewska
- Faculty of Chemistry, University of Warsaw, Zwirki i Wigury 101, Warsaw, 02-089, Poland
| | - Ewan Cruickshank
- Department of Chemistry, King's College, University of Aberdeen, Aberdeen, AB24 3UE, UK
| | - Rebecca Walker
- Department of Chemistry, King's College, University of Aberdeen, Aberdeen, AB24 3UE, UK
| | - John M D Storey
- Department of Chemistry, King's College, University of Aberdeen, Aberdeen, AB24 3UE, UK
| | - Corrie T Imrie
- Department of Chemistry, King's College, University of Aberdeen, Aberdeen, AB24 3UE, UK
| | - Cheng Wang
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Ewa Gorecka
- Faculty of Chemistry, University of Warsaw, Zwirki i Wigury 101, Warsaw, 02-089, Poland
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29
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Yamamoto K, Toguchi H, Kuriyama M, Watanabe S, Iwasaki F, Onomura O. Electrophotochemical Ring-Opening Bromination of tert-Cycloalkanols. J Org Chem 2021; 86:16177-16186. [PMID: 34461014 DOI: 10.1021/acs.joc.1c01264] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
An electrophotochemical ring-opening bromination of unstrained tert-cycloalkanols has been developed. This electrophotochemical method enables the oxidative transformation of cycloalkanols with 5- to 7-membered rings into synthetically useful ω-bromoketones without the use of chemical oxidants or transition-metal catalysts. Alkoxy radical species would be key intermediates in the present transformation, which generate through homolysis of the O-Br bond in hypobromite intermediates under visible light irradiation.
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Affiliation(s)
- Kosuke Yamamoto
- Graduate School of Biomedical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan
| | - Hiroyuki Toguchi
- Graduate School of Biomedical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan
| | - Masami Kuriyama
- Graduate School of Biomedical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan
| | - Shin Watanabe
- Tsukuba Research Laboratories, Tokuyama Corporation, 40 Wadai, Tsukuba, Ibaraki 300-4247, Japan
| | - Fumiaki Iwasaki
- Tsukuba Research Laboratories, Tokuyama Corporation, 40 Wadai, Tsukuba, Ibaraki 300-4247, Japan
| | - Osamu Onomura
- Graduate School of Biomedical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan
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30
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Alaasar M, Schmidt JC, Cai X, Liu F, Tschierske C. Controlling liquid and liquid crystalline network formation by core-fluorination of hydrogen bonded supramolecular polycatenars. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.115870] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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31
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Liu J, Shadpour S, Prévôt ME, Chirgwin M, Nemati A, Hegmann E, Lemieux RP, Hegmann T. Molecular Conformation of Bent-Core Molecules Affected by Chiral Side Chains Dictates Polymorphism and Chirality in Organic Nano- and Microfilaments. ACS NANO 2021; 15:7249-7270. [PMID: 33734664 DOI: 10.1021/acsnano.1c00527] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The coupling between molecular conformation and chirality is a cornerstone in the construction of supramolecular helical structures of small molecules across various length scales. Inspired by biological systems, conformational preselection and control in artificial helical molecules, polymers, and aggregates has guided various applications in optics, photonics, and chiral sorting among others, which are frequently based on an inherent chirality amplification through processes such as templating and self-assembly. The so-called B4 nano- or microfilament phase formed by some bent-shaped molecules is an exemplary case for such chirality amplification across length scales, best illustrated by the formation of distinct nano- or microscopic chiral morphologies controlled by molecular conformation. Introduction of one or more chiral centers in the aliphatic side chains led to the discovery of homochiral helical nanofilament, helical microfilament, and heliconical-layered nanocylinder morphologies. Herein, we demonstrate how a priori calculations of the molecular conformation affected by chiral side chains are used to design bent-shaped molecules that self-assemble into chiral nano- and microfilament as well as nanocylinder conglomerates despite the homochiral nature of the molecules. Furthermore, relocation of the chiral center leads to formation of helical as well as flat nanoribbons. Self-consistent data sets from polarized optical as well as scanning and transmission electron microscopy, thin-film and solution circular dichroism spectropolarimetry, and synchrotron-based X-ray diffraction experiments support the progressive and predictable change in morphology controlled by structural changes in the chiral side chains. The formation of these morphologies is discussed in light of the diminishing effects of molecular chirality as the chain length increases or as the chiral center is moved away from the core-chain juncture. The type of phase (B1-columnar or B4) and morphology of the nano- or microfilaments generated can further be controlled by sample treatment conditions such as by the cooling rate from the isotropic melt or by the presence of an organic solvent in the ensuing colloidal dispersions. We show that these nanoscale morphologies can then organize into a wealth of two- and three-dimensional shapes and structures ranging from flower blossoms to fiber mats formed by intersecting flat nanoribbons.
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Affiliation(s)
- Jiao Liu
- Materials Science Graduate Program, Kent State University, Kent (Ohio) 44242-0001, United States
- Advanced Materials and Liquid Crystal Institute, Kent State University, Kent (Ohio) 44242-0001, United States
| | - Sasan Shadpour
- Materials Science Graduate Program, Kent State University, Kent (Ohio) 44242-0001, United States
- Advanced Materials and Liquid Crystal Institute, Kent State University, Kent (Ohio) 44242-0001, United States
| | - Marianne E Prévôt
- Advanced Materials and Liquid Crystal Institute, Kent State University, Kent (Ohio) 44242-0001, United States
| | - Michael Chirgwin
- Advanced Materials and Liquid Crystal Institute, Kent State University, Kent (Ohio) 44242-0001, United States
| | - Ahlam Nemati
- Materials Science Graduate Program, Kent State University, Kent (Ohio) 44242-0001, United States
- Advanced Materials and Liquid Crystal Institute, Kent State University, Kent (Ohio) 44242-0001, United States
| | - Elda Hegmann
- Materials Science Graduate Program, Kent State University, Kent (Ohio) 44242-0001, United States
- Advanced Materials and Liquid Crystal Institute, Kent State University, Kent (Ohio) 44242-0001, United States
- Department of Biological Sciences, Kent State University, Kent, Ohio 44242-0001, United States
- Brain Health Research Institute, Kent State University, Kent, Ohio 44242-0001, United States
| | - Robert P Lemieux
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Torsten Hegmann
- Materials Science Graduate Program, Kent State University, Kent (Ohio) 44242-0001, United States
- Advanced Materials and Liquid Crystal Institute, Kent State University, Kent (Ohio) 44242-0001, United States
- Department of Biological Sciences, Kent State University, Kent, Ohio 44242-0001, United States
- Brain Health Research Institute, Kent State University, Kent, Ohio 44242-0001, United States
- Department of Chemistry and Biochemistry, Kent State University, Kent, Ohio 44242-0001, United States
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32
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Arakawa Y, Komatsu K, Shiba T, Tsuji H. Phase behaviors of classic liquid crystal dimers and trimers: Alternate induction of smectic and twist-bend nematic phases depending on spacer parity for liquid crystal trimers. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.115319] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Saha R, Feng C, Welch C, Mehl GH, Feng J, Zhu C, Gleeson J, Sprunt S, Jákli A. The interplay between spatial and heliconical orientational order in twist-bend nematic materials. Phys Chem Chem Phys 2021; 23:4055-4063. [PMID: 33587066 DOI: 10.1039/d0cp06633h] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The helical pitch formed by organic molecules, such as the α-helix of proteins, usually requires hydrogen bonding between chiral units and long-range positional order. It was recently found that certain liquid crystal oligomers can have a twist-bend nematic (NTB) phase with nanoscale heliconical structure without hydrogen bonding, molecular chirality or positional order. To understand the nature of this unique structure, here we present hard and resonant tender X-ray scattering studies of two novel sulfur containing dimer materials. We simultaneously measure the temperature dependences of the helical pitch and the correlation length of both the helical and positional order. In addition to an unexpected strong variation of the pitch with the length of the spacer connecting the monomer units, we find that at the transition to the NTB phase the positional correlation length drops. The helical structure was found not only in the NTB phase but observed even in the upper range of a smectic phase that forms just below the NTB state. The coexistence of smectic layering and the heliconical order indicates a layered (SmATB) phase wherein the rigid units of the dimers are tilted with respect to the smectic layer normal in order to accommodate the bent conformation of the dimers and the tilt direction rotates along the heliconical axis.
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Affiliation(s)
- R Saha
- Department of Physics, Kent State University, Kent, OH 44242, USA.
| | - C Feng
- Materials Science Graduate Program, Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, OH 44242, USA and Advanced Light Source, Lawrence Berkeley National Lab, Berkeley, CA 94720, USA
| | - C Welch
- Department of Chemistry, University of Hull, Hull, UK
| | - G H Mehl
- Department of Chemistry, University of Hull, Hull, UK
| | - J Feng
- Advanced Light Source, Lawrence Berkeley National Lab, Berkeley, CA 94720, USA
| | - C Zhu
- Advanced Light Source, Lawrence Berkeley National Lab, Berkeley, CA 94720, USA
| | - J Gleeson
- Department of Physics, Kent State University, Kent, OH 44242, USA.
| | - S Sprunt
- Department of Physics, Kent State University, Kent, OH 44242, USA. and Materials Science Graduate Program, Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, OH 44242, USA
| | - A Jákli
- Department of Physics, Kent State University, Kent, OH 44242, USA. and Materials Science Graduate Program, Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, OH 44242, USA
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Walker R, Majewska M, Pociecha D, Makal A, Storey JM, Gorecka E, Imrie CT. Twist-Bend Nematic Glasses: The Synthesis and Characterisation of Pyrene-based Nonsymmetric Dimers. Chemphyschem 2021; 22:461-470. [PMID: 33369044 DOI: 10.1002/cphc.202000993] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Indexed: 12/17/2022]
Abstract
A selection of pyrene-based liquid crystal dimers have been prepared, containing either methylene-ether or diether linked spacers of varying length and parity. All the diether linked materials, CBOnO.Py (n=5, 6, 11, 12), exhibit conventional nematic and smectic A phases, with the exception of CBO11O.Py which is exclusively nematic. The methylene-ether linked dimer, CBnO.Py, with an even-membered spacer (n=5) was solely nematogenic, but odd-members (n=6, 8, 10) exhibited both nematic and twist-bend nematic phases. Replacement of the cyanobiphenyl fragment by cyanoterphenyl giving CT6O.Py, gave elevated melting and nematic-isotropic transition temperatures, and SmA and SmCA phases were observed on cooling the nematic phase. Intermolecular face-to-face associations of the pyrene moieties drive glass formation, and all these materials have a glass transition temperature at or above room temperature. The stability of the glassy twist-bend nematic phase allowed for its study using AFM, and the helical pitch length, PTB , was measured as 6.3 and 6.7 nm for CB6O.Py and CB8O.Py, respectively. These values are comparable to the shortest pitch of a twist-bend nematic phase measured to date.
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Affiliation(s)
- Rebecca Walker
- Department of Chemistry, School of Natural and Computing Sciences, University of Aberdeen, Meston Building, Aberdeen, AB24 3UE, UK
| | - Magdalena Majewska
- Faculty of Chemistry, University of Warsaw, ul. Zwirki I Wigury 101, 02-089, Warsaw, Poland
| | - Damian Pociecha
- Faculty of Chemistry, University of Warsaw, ul. Zwirki I Wigury 101, 02-089, Warsaw, Poland
| | - Anna Makal
- Faculty of Chemistry, University of Warsaw, ul. Zwirki I Wigury 101, 02-089, Warsaw, Poland
| | - John Md Storey
- Department of Chemistry, School of Natural and Computing Sciences, University of Aberdeen, Meston Building, Aberdeen, AB24 3UE, UK
| | - Ewa Gorecka
- Faculty of Chemistry, University of Warsaw, ul. Zwirki I Wigury 101, 02-089, Warsaw, Poland
| | - Corrie T Imrie
- Department of Chemistry, School of Natural and Computing Sciences, University of Aberdeen, Meston Building, Aberdeen, AB24 3UE, UK
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Pocock EE, Mandle RJ, Goodby JW. Experimental and Computational Study of a Liquid Crystalline Dimesogen Exhibiting Nematic, Twist-Bend Nematic, Intercalated Smectic, and Soft Crystalline Mesophases. Molecules 2021; 26:532. [PMID: 33498518 PMCID: PMC7864162 DOI: 10.3390/molecules26030532] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 01/18/2021] [Accepted: 01/19/2021] [Indexed: 11/16/2022] Open
Abstract
Liquid crystalline dimers and dimesogens have attracted significant attention due to their tendency to exhibit twist-bend modulated nematic (NTB) phases. While the features that give rise to NTB phase formation are now somewhat understood, a comparable structure-property relationship governing the formation of layered (smectic) phases from the NTB phase is absent. In this present work, we find that by selecting mesogenic units with differing polarities and aspect ratios and selecting an appropriately bent central spacer we obtain a material that exhibits both NTB and intercalated smectic phases. The higher temperature smectic phase is assigned as SmCA based on its optical textures and X-ray scattering patterns. A detailed study of the lower temperature smectic ''X'' phase by optical microscopy and SAXS/WAXS demonstrates this phase to be smectic, with an in-plane orthorhombic or monoclinic packing and long (>100 nm) out of plane correlation lengths. This phase, which has been observed in a handful of materials to date, is a soft-crystal phase with an anticlinic layer organisation. We suggest that mismatching the polarities, conjugation and aspect ratios of mesogenic units is a useful method for generating smectic forming dimesogens.
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Affiliation(s)
- Emily E. Pocock
- Department of Chemistry, University of York, Heslington, York YO10 5DD, UK;
| | - Richard J. Mandle
- Department of Chemistry, University of York, Heslington, York YO10 5DD, UK;
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK
| | - John W. Goodby
- Department of Chemistry, University of York, Heslington, York YO10 5DD, UK;
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Chemical-Physical Characterization of a Binary Mixture of a Twist Bend Nematic Liquid Crystal with a Smectogen. CRYSTALS 2020. [DOI: 10.3390/cryst10121110] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Nematic twist-bend phases (NTB) are new types of nematic liquid crystalline phases with attractive properties for future electro-optic applications. However, most of these states are monotropic or are stable only in a narrow high temperature range. They are often destabilized under moderate cooling, and only a few single compounds have shown to give room temperature NTB phases. Mixtures of twist-bend nematic liquid crystals with simple nematogens have shown to strongly lower the nematic to NTB phase transition temperature. Here, we examined the behaviour of new types of mixtures with the dimeric liquid crystal [4′,4′-(heptane-1,7-diyl)bis(([1′,1″-biphenyl]4″-carbo-nitrile))] (CB7CB). This now well-known twist-bend nematic liquid crystal presents a nematic twist-bend phase below T ≈ 104 °C. Mixtures with other monomeric alkyl or alkoxy -biphenylcarbonitriles liquid crystals that display a smectic A (SmA) phase also strongly reduce this temperature. The most interesting smectogen is 4′-Octyl-4-biphenylcarbonitrile (8CB), for which a long-term metastable NTB phase is found at room and lower temperatures. This paper presents the complete phase diagram of the corresponding binary system and a detailed investigation of its thermal, optical, dielectric, and elastic properties.
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Forsyth E, Paterson DA, Cruickshank E, Strachan GJ, Gorecka E, Walker R, Storey JM, Imrie CT. Liquid crystal dimers and the twist-bend nematic phase: On the role of spacers and terminal alkyl chains. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2020.114391] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Al-Mutabagani LA, Alshabanah LA, Naoum MM, Hagar M, Ahmed HA. Experimental and Computational Approaches of Newly Polymorphic Supramolecular H-Bonded Liquid Crystal Complexes. Front Chem 2020; 8:571120. [PMID: 33240841 PMCID: PMC7667271 DOI: 10.3389/fchem.2020.571120] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 09/07/2020] [Indexed: 12/21/2022] Open
Abstract
New 1:2 liquid crystalline supramolecular H-bonded complexes (SMHBCs) were synthesized through double H-bond interactions between 4-(nicotinoyloxy) phenyl nicotinate as the base component and two molecules of 4-n-alkoxybenzoic acid (An). The base component was expected to be in two conformers according to the orientation of the N atom and the carboxylate group, syn conformer (I) and anti-conformer (II). DFT calculations revealed that only one of the two possible conformers of I exists, and the addition of the two molecules of the alkoxy acids (A n) did not affect its conformation. The mesomorphic properties of all of the prepared complexes (I/A n), bearing different terminal flexible alkoxy chains were investigated, and the formation of the H-bonds were confirmed by differential scanning calorimetry (DSC), and the phases were identified by polarized optical microscopy (POM), and FT-IR spectroscopy. Highly thermally stable mesophases possessing broad temperature ranges were observed for all investigated complexes compared to their individual components. Depending on the length of the terminal flexible alkoxy chain, the prepared SMHBCs were shown to exhibit di- or tri-morphic enantiotropic mesophases. The effect of replacing one of the -COO- connecting units by an azo group (-N=N-) in the basic molecule (I), on the mesomorphic properties has been investigated experimentally (via DSC) and theoretically (via DFT). The DFT calculations revealed that the polarizability, the dipole moment, and the aspect ratio of the investigated SMHBCs are lower than those of their corresponding ester/azo analogs. All these factors rationalize the enhanced smectic mesophase ranges of the complexes compared with those of the ester/azo analogs. The high aspect ratios and dipole moments of the SMHBCs of the azo derivative enforces the lateral intermolecular attraction that permits the formation of the more ordered smectic C mesophase with respect to the enhanced polymorphic mesophases of the diester derivative.
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Affiliation(s)
- Laila A. Al-Mutabagani
- Chemistry Department, College of Science, Princess Nourah Bint Abdulrahman University, Riyadh, Saudi Arabia
| | | | - Magdi M. Naoum
- Department of Chemistry, Faculty of Science, Cairo University, Cairo, Egypt
| | - Mohamed Hagar
- Chemistry Department, College of Sciences, Taibah University, Yanbu, Saudi Arabia
- Chemistry Department, Faculty of Science, Alexandria University, Alexandria, Egypt
| | - Hoda A. Ahmed
- Department of Chemistry, Faculty of Science, Cairo University, Cairo, Egypt
- Chemistry Department, College of Sciences, Taibah University, Yanbu, Saudi Arabia
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Ariga K, Mori T, Kitao T, Uemura T. Supramolecular Chiral Nanoarchitectonics. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e1905657. [PMID: 32191374 DOI: 10.1002/adma.201905657] [Citation(s) in RCA: 110] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 12/26/2019] [Indexed: 05/06/2023]
Abstract
Exploration of molecular functions and material properties based on the control of chirality would be a scientifically elegant approach. Here, the fabrication and function of chiral-featured materials from both chiral and achiral components using a supramolecular nanoarchitectonics concept are discussed. The contents are classified in to three topics: i) chiral nanoarchitectonics of rather general molecular assemblies; ii) chiral nanoarchitectonics of metal-organic frameworks (MOFs); iii) chiral nanoarchitectonics in liquid crystals. MOF structures are based on nanoscopically well-defined coordinations, while mesoscopic orientations of liquid-crystalline phases are often flexibly altered. Discussion on the effects and features in these representative materials systems with totally different natures reveals the universal importance of supramolecular chiral nanoarchitectonics. Amplification of chiral molecular information from molecules to materials-level structures and the creation of chirality from achiral components upon temporal statistic fluctuations are universal, regardless of the nature of the assemblies. These features are thus surely advantageous characteristics for a wide range of applications.
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Affiliation(s)
- Katsuhiko Ariga
- WPI-MANA, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki, 305-0044, Japan
- Department of Advanced Materials Science, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8561, Japan
| | - Taizo Mori
- WPI-MANA, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki, 305-0044, Japan
- Department of Advanced Materials Science, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8561, Japan
| | - Takashi Kitao
- Department of Advanced Materials Science, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8561, Japan
- Department of Applied Chemistry, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - Takashi Uemura
- Department of Advanced Materials Science, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8561, Japan
- Department of Applied Chemistry, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
- CREST, Japan Science and Technology Agency (JST), 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012, Japan
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40
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Nematogenic Laterally Substituted Supramolecular H-Bonded Complexes Based on Flexible Core. CRYSTALS 2020. [DOI: 10.3390/cryst10100878] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
New laterally CH3-substituted series of 1:2 hydrogen-bonded supramolecular complexes (HBSMCs) based on flexible acid core were prepared and mesomorphically investigated. Mixtures were formed through H-bonded interactions between adipic acid (A) and 4-(2-(pyridin-4-yl)diazenyl-(3-methylphenyl) 4-alkoxybenzoate (Bn). Mesomorphic and optical properties were investigated by differential scanning calorimetry (DSC), polarized optical microscopy (POM), X-ray diffraction (XRD), and UV-spectroscopy. HBSMCs formed from 1:2 mol mixture of A:2Bn, where the base component (B) bearing different alkoxy chain lengths from n = 8 to 14. The new HBSMCs (A/2B) interactions were confirmed by Fermi-bands formation via FT-IR spectroscopy measurements. Results revealed that all prepared HBSMCs are enantiotropic, exhibiting induced nematic (N) phase. The XRD pattern confirmed the POM texture results. Moreover, a comparison was made between the new laterally HBSMC series based on flexible core and the previously analyzed laterally neat complexes.
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41
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Nematic Phase Induced from Symmetrical Supramolecular H-Bonded Systems Based on Flexible Acid Core. CRYSTALS 2020. [DOI: 10.3390/cryst10090801] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
New symmetrical 1:2 supramolecular H-bonded liquid crystals (SMHBLCs) interactions, A/2Bn, were formed between adipic acid and 4-(4′–pyridylazophenyl) 4″-alkoxybenzoates. Optical and mesomorphic behaviors of the prepared SMHBLC complexes were investigated using differential scanning calorimetry (DSC), polarizing optical microscopy (POM) and X-ray diffraction (XRD). FT-IR spectroscopy was carried out to confirm the H-bond interactions of the prepared complexes via Fermi bands formation. Their photo-physical properties were investigated by UV-spectroscopy and the observed absorbance values were found to be mainly dependent on the length of the terminal alkoxy chain. Mesomorphic behaviour for all A/2Bn complexes revealed that all complexes are dimorphic-exhibiting enantiotropic mesophases with induced nematic phases, except for the long chain terminal complex which exhibits only a monomorphic smectic A phase. In order to investigate the effect of mesogenic core geometry on the mesophase properties, a comparison was established between the mesomeric behaviors of the present complexes and previously reported rigid core acid complexes. Finally, the XRD pattern confirmed the POM and DSC results.
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42
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Vita F, Adamo FC, Pisani M, Francescangeli O. Nanostructure of Unconventional Liquid Crystals Investigated by Synchrotron Radiation. NANOMATERIALS (BASEL, SWITZERLAND) 2020; 10:E1679. [PMID: 32859117 PMCID: PMC7558469 DOI: 10.3390/nano10091679] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 07/27/2020] [Accepted: 08/12/2020] [Indexed: 11/30/2022]
Abstract
The macroscopic properties of novel liquid crystal (LC) systems-LCs with unconventional molecular structure as well as conventional LCs in unconventional geometries-directly descend from their mesoscopic structural organization. While X-ray diffraction (XRD) is an obvious choice to investigate their nanoscale structure, conventional diffractometry is often hampered by experimental difficulties: the low scattering power and short-range positional order of the materials, resulting in weak and diffuse diffraction features; the need to perform measurements in challenging conditions, e.g., under magnetic and/or electric fields, on thin films, or at high temperatures; and the necessity to probe micron-sized volumes to tell the local structural properties from their macroscopic average. Synchrotron XRD allows these problems to be circumvented thanks to the superior diffraction capabilities (brilliance, q-range, energy and space resolution) and advanced sample environment available at synchrotron beamlines. Here, we highlight the potentiality of synchrotron XRD in the field of LCs by reviewing a selection of experiments on three unconventional LC systems: the potentially biaxial and polar nematic phase of bent-core mesogens; the very high-temperature nematic phase of all-aromatic LCs; and polymer-dispersed liquid crystals. In all these cases, synchrotron XRD unveils subtle nanostructural features that are reflected into macroscopic properties of great interest from both fundamental and technological points of view.
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Affiliation(s)
| | | | | | - Oriano Francescangeli
- Dipartimento di Scienze e Ingegneria della Materia, dell’Ambiente ed Urbanistica, Università Politecnica delle Marche, via Brecce Bianche, 60131 Ancona, Italy; (F.V.); (F.C.A.); (M.P.)
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43
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Matsuyama A. Phase transitions of heliconical smectic-C and heliconical nematic phases in banana-shaped liquid crystals. Phys Rev E 2020; 101:050701. [PMID: 32575293 DOI: 10.1103/physreve.101.050701] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 05/10/2020] [Indexed: 11/07/2022]
Abstract
A mean-field theory is introduced to describe heliconical nematic (N_{TB}), heliconical smectic-C (S_{m}C_{TB}), and biaxial heliconical smectic-C (S_{m}C_{TB,b}) phases with mirror symmetry breaking. We extend our previous theories of the N_{TB} phase to the heliconical smectic-C phases, by taking into account one-dimensional spatial ordering of smectic layers. The calculated phase diagrams on the temperature-alkyl chain length plane show a rich variety of phase transitions: first- and second-order N_{TB}-S_{m}C_{TB} transitions, etc., including tricritical, tetracritical, and multicritical points. Our theory is qualitatively consistent with an experimental phase diagram.
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Affiliation(s)
- Akihiko Matsuyama
- Department of Physics and Information Technology, Faculty of Computer Science and Systems Engineering, Kyushu Institute of Technology, Kawazu 680-4, Iizuka, Fukuoka 820-8502, Japan
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44
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Walker R. The twist-bend phases: structure–property relationships, chirality and hydrogen-bonding. LIQUID CRYSTALS TODAY 2020. [DOI: 10.1080/1358314x.2020.1771841] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Rebecca Walker
- Department of Chemistry, University of Aberdeen, Aberdeen, UK
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45
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Lee JJ, Kim BC, Choi HJ, Bae S, Araoka F, Choi SW. Inverse Helical Nanofilament Networks Serving as a Chiral Nanotemplate. ACS NANO 2020; 14:5243-5250. [PMID: 32227912 DOI: 10.1021/acsnano.0c00393] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Herein, an epoch-making method based on bottom-up templating is proposed for the fabrication of a chiral nanoporous film that provides a chiral environment in which to confine nematic liquid crystals. A helical nanofilamental network of bent-core molecules was utilized as a three-dimensional mold, and thus the fabricated chiral nanoporous film has an inverse nanohelical structure. The presence of a chiral superstructure was confirmed by the observation of circular dichroism signals. Upon refilling this chiral nanoporous film with an achiral nematic liquid crystal, distinct circular dichroism signals appeared due to the transfer of chirality from the inverse helical nanofilaments to the achiral nematic liquid crystal. The circular dichroism signals can be readily modulated by external stimuli, such as the application of heat or an electric field. In addition, by refilling the chiral nanoporous film with a nematic liquid crystal doped with fluorescent dye, it exhibits stimuli-responsive circularly polarized luminescence. The proposed approach has huge potential for practical applications, such as for chiroptical modulators and switches and biological sensors.
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Affiliation(s)
- Jae-Jin Lee
- Department of Advanced Materials Engineering for Information and Electronics (BK21Plus) Kyung Hee University, Yongin-shi, Gyeonggi-do 17104, Korea
| | - Byeong-Cheon Kim
- Department of Advanced Materials Engineering for Information and Electronics (BK21Plus) Kyung Hee University, Yongin-shi, Gyeonggi-do 17104, Korea
| | - Hyeon-Joon Choi
- Department of Advanced Materials Engineering for Information and Electronics (BK21Plus) Kyung Hee University, Yongin-shi, Gyeonggi-do 17104, Korea
| | - Sangwok Bae
- Department of Advanced Materials Engineering for Information and Electronics (BK21Plus) Kyung Hee University, Yongin-shi, Gyeonggi-do 17104, Korea
| | - Fumito Araoka
- Physicochemical Soft Matter Research Unit, RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan
| | - Suk-Won Choi
- Department of Advanced Materials Engineering for Information and Electronics (BK21Plus) Kyung Hee University, Yongin-shi, Gyeonggi-do 17104, Korea
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46
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Tomczyk W, Longa L. Role of molecular bend angle and biaxiality in the stabilization of the twist-bend nematic phase. SOFT MATTER 2020; 16:4350-4357. [PMID: 32347876 DOI: 10.1039/d0sm00078g] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
What are the prerequisites for acquiring a stable twist-bend nematic phase (NTB)? Addressing this question has led to the synthesis of a vast number of new compounds, concluding each time that the molecule's shape is one of the predominant factors. Inspired by the expanding knowledge of different achiral bent-shaped molecules forming a twist-bend nematic phase, we reinvestigate the interplay between a molecule's bend angle and a molecule's arms molecular biaxiality. Employing our previously developed generalized mean-field model, we explore more obtuse bend angles. We observe direct phase transition sequences between locally biaxial and uniaxial variants of NTB, along with biaxial and uniaxial nematic phases. Additionally, we present a comprehensive overview of how phase diagrams evolve according to alterations in the value of the bend angle and the magnitude of biaxiality.
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Affiliation(s)
- Wojciech Tomczyk
- Institute of Theoretical Physics, Jagiellonian University, Łojasiewicza 11, 30-348 Kraków, Poland.
| | - Lech Longa
- Institute of Theoretical Physics, Jagiellonian University, Łojasiewicza 11, 30-348 Kraków, Poland.
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47
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Lehmann A, Alaasar M, Poppe M, Poppe S, Prehm M, Nagaraj M, Sreenilayam SP, Panarin YP, Vij JK, Tschierske C. Stereochemical Rules Govern the Soft Self-Assembly of Achiral Compounds: Understanding the Heliconical Liquid-Crystalline Phases of Bent-Core Mesogens. Chemistry 2020; 26:4714-4733. [PMID: 31859404 PMCID: PMC7186843 DOI: 10.1002/chem.201904871] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 12/15/2019] [Indexed: 11/16/2022]
Abstract
A series of bent-shaped 4-cyanoresorcinol bisterephthalates is reported. Some of these achiral compounds spontaneously form a short-pitch heliconical lamellar liquid-crystalline phase with incommensurate 3-layer pitch and the helix axis parallel to the layer normal. It is observed at the paraelectric-(anti)ferroelectric transition, if it coincides with the transition from random to uniform tilt and with the transition from anticlinic to synclinic tilt correlation of the molecules in the layers of the developing tilted smectic phase. For compounds with long chains the heliconical phase is only field-induced, but once formed it is stable in a distinct temperature range, even after switching off the field. The presence of the helix changes the phase properties and the switching mechanism from the naturally preferred rotation around the molecular long axis, which reverses the chirality, to a precession on a cone, which retains the chirality. These observations are explained by diastereomeric relations between two coexisting modes of superstructural chirality. One is the layer chirality, resulting from the combination of tilt and polar order, and the other one is the helical twist evolving between the layers. At lower temperature the helical structure is replaced by a non-tilted and ferreoelectric switching lamellar phase, providing an alternative non-chiral way for the transition from anticlinic to synclinic tilt.
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Affiliation(s)
- Anne Lehmann
- Department of ChemistryMartin Luther University Halle-WittenbergKurt Mothes Str. 206120Halle (Saale)Germany
| | - Mohamed Alaasar
- Department of ChemistryMartin Luther University Halle-WittenbergKurt Mothes Str. 206120Halle (Saale)Germany
- Department of ChemistryCairo University12613GizaEgypt
| | - Marco Poppe
- Department of ChemistryMartin Luther University Halle-WittenbergKurt Mothes Str. 206120Halle (Saale)Germany
| | - Silvio Poppe
- Department of ChemistryMartin Luther University Halle-WittenbergKurt Mothes Str. 206120Halle (Saale)Germany
| | - Marko Prehm
- Department of ChemistryMartin Luther University Halle-WittenbergKurt Mothes Str. 206120Halle (Saale)Germany
| | - Mamatha Nagaraj
- Department of Electronic and Electrical EngineeringTrinity College, Dublin, The University of DublinDublin2Ireland
| | - Sithara P. Sreenilayam
- Department of Electronic and Electrical EngineeringTrinity College, Dublin, The University of DublinDublin2Ireland
| | - Yuri P. Panarin
- Department of Electronic and Electrical EngineeringTrinity College, Dublin, The University of DublinDublin2Ireland
| | - Jagdish K. Vij
- Department of Electronic and Electrical EngineeringTrinity College, Dublin, The University of DublinDublin2Ireland
| | - Carsten Tschierske
- Department of ChemistryMartin Luther University Halle-WittenbergKurt Mothes Str. 206120Halle (Saale)Germany
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Abdullah Alshabanah L, Al-Mutabagani LA, Ahmed HA, Hagar M. Induced Wide Nematic Phase by Seven-Ring Supramolecular H-Bonded Systems: Experimental and Computational Evaluation. Molecules 2020; 25:E1694. [PMID: 32272753 PMCID: PMC7180779 DOI: 10.3390/molecules25071694] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 03/31/2020] [Accepted: 04/03/2020] [Indexed: 11/25/2022] Open
Abstract
New seven-ring systems of dipyridine derivative liquid crystalline 2:1 supramolecular H-bonded complexes were formed between 4-n-alkoxyphenylazo benzoic acids and 4-(2-(pyridin-4-yl)diazenyl)phenyl nicotinate. Mesomorphic behaviors of the prepared complexes were investigated using a combination of differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). Fermi bands attributed to the presence of intermolecular H-bond interactions were confirmed by FT-IR spectroscopy. All prepared complexes possessed an enantiotropic nematic phase with a broad temperature nematogenic range. Phases were confirmed by miscibility with a standard nematic (N) compound. A comparison was constructed to investigate the influence of the incorporation of the azophenyl moiety on the mesomeric behavior of corresponding five-membered complexes. It was found that the present complexes observed induced a wide nematic phase with relatively higher temperature ranges than the five aromatic systems. Density functional theory (DFT ) suggested the nonlinear geometry of the formed complex. The results of the DFT explained the nematic mesophase formation. Moreover, the π-π stacking of the aromatic moiety in the phenylazo acid plays an effective role in the mesomorphic thermal stability. The energy difference between the frontier molecular orbitals, HOMO (highest occupied) and LUMO (lowest occupied), and the molecular electrostatic potential (MEP) of the prepared complexes were estimated by DFT calculations. The results were used to illustrate the observed nematic phase for all H-bonded supramolecular complexes. Finally, photophysical studies were discussed which were carried out by UV spectroscopy connected to a hot stage.
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Affiliation(s)
- Latifah Abdullah Alshabanah
- Chemistry Department, College of Science, Princess Nourah bint Abdulrahman University, Riyadh 11671, Saudi Arabia; (L.A.A.); (L.A.A.-M.)
| | - Laila A. Al-Mutabagani
- Chemistry Department, College of Science, Princess Nourah bint Abdulrahman University, Riyadh 11671, Saudi Arabia; (L.A.A.); (L.A.A.-M.)
| | - Hoda A. Ahmed
- Department of Chemistry, Faculty of Science, Cairo University, Cairo 12613, Egypt
- Chemistry Department, College of Sciences, Yanbu, Taibah University, Yanbu 30799, Saudi Arabia
| | - Mohamed Hagar
- Chemistry Department, College of Sciences, Yanbu, Taibah University, Yanbu 30799, Saudi Arabia
- Chemistry Department, Faculty of Science, Alexandria University, Alexandria 21321, Egypt
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Al-Mutabagani LA, Alshabanah LA, Ahmed HA, Hagar M, Al-Ola KAA. New Symmetrical U- and Wavy-Shaped Supramolecular H-Bonded Systems; Geometrical and Mesomorphic Approaches. Molecules 2020; 25:E1420. [PMID: 32245001 PMCID: PMC7144929 DOI: 10.3390/molecules25061420] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 03/10/2020] [Accepted: 03/11/2020] [Indexed: 01/28/2023] Open
Abstract
New mesomorphic symmetrical 2:1 supramolecular H-bonded complexes of seven phenyl rings were prepared between 4-n-alkoxyphenylazobenzoic acids and 4-(2-(pyridin-3-yl)diazenyl)phenyl nicotinate. Mesomorphic studies of the prepared complexes were investigated using differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). Fermi bands of the formed H-bonded interactions were confirmed by FT-IR spectroscopy. Geometrical parameters for all complexes were performed using the density functional theory (DFT) calculations method. Theoretical results revealed that the prepared H-bonded complexes are in non-linear geometry with U-shaped and wavy-shaped geometrical structures; however, the greater linearity of the wavy-shaped compounds could be the reason for their stability with respect to the U-shaped conformer. Moreover, the stable, wavy shape of supramolecular H-bonded complexes (SMHBCs) has been used to illustrate mesomeric behavior in terms of the molecular interaction. The experimental mesomorphic investigations revealed that all complexes possess enantiotropic smectic C phase. Phases were confirmed by miscibility with a standard smectic C (SmC) compound. A comparison was constructed to investigate the effect of incorporating azophenyl moiety into the mesomeric behavior of the corresponding five-membered complexes. It was found that the addition of the extra phenylazo group to the acid moiety has a great increment of the mesophase stability (TC) values with respect to the monotropic SmC phase of the five aromatic systems to the high stable enantiotropic SmC mesophase.
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Affiliation(s)
- Laila A. Al-Mutabagani
- College of Science, Chemistry Department, Riyadh, Princess Nourah bint Abdulrahman University, Riyadh 11671, Saudi Arabia; (L.A.A.-M); (L.A.A.)
| | - Latifah Abdullah Alshabanah
- College of Science, Chemistry Department, Riyadh, Princess Nourah bint Abdulrahman University, Riyadh 11671, Saudi Arabia; (L.A.A.-M); (L.A.A.)
| | - Hoda A. Ahmed
- Faculty of Science, Department of Chemistry, Cairo University, Cairo 12613, Egypt
- Chemistry Department, College of Sciences, Yanbu, Taibah University, Yanbu 30799, Saudi Arabia
| | - Mohamed Hagar
- Chemistry Department, College of Sciences, Yanbu, Taibah University, Yanbu 30799, Saudi Arabia
- Faculty of Science, Chemistry Department, Alexandria University, Alexandria 21321, Egypt
| | - Khulood A. Abu Al-Ola
- Chemistry Department, College of Sciences, Al-Madina Al-Munawarah, Taibah University, Al-Madina 30002, Saudi Arabia;
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