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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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2
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Sezgin B, Liu J, N. Gonçalves DP, Zhu C, Tilki T, Prévôt ME, Hegmann T. Controlling the Structure and Morphology of Organic Nanofilaments Using External Stimuli. ACS NANOSCIENCE AU 2023; 3:295-309. [PMID: 37601923 PMCID: PMC10436377 DOI: 10.1021/acsnanoscienceau.3c00005] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 04/05/2023] [Accepted: 04/06/2023] [Indexed: 08/22/2023]
Abstract
In our continuing pursuit to generate, understand, and control the morphology of organic nanofilaments formed by molecules with a bent molecular shape, we here report on two bent-core molecules specifically designed to permit a phase or morphology change upon exposure to an applied electric field or irradiation with UV light. To trigger a response to an applied electric field, conformationally rigid chiral (S,S)-2,3-difluorooctyloxy side chains were introduced, and to cause a response to UV light, an azobenzene core was incorporated into one of the arms of the rigid bent core. The phase behavior as well as structure and morphology of the formed phases and nanofilaments were analyzed using differential scanning calorimetry, cross-polarized optical microscopy, circular dichroism spectropolarimetry, scanning and transmission electron microscopy, UV-vis spectrophotometry, as well as X-ray diffraction experiments. Both bent-core molecules were characterized by the coexistence of two nanoscale morphologies, specifically helical nanofilaments (HNFs) and layered nanocylinders, prior to exposure to an external stimulus and independent of the cooling rate from the isotropic liquid. The application of an electric field triggers the disappearance of crystalline nanofilaments and instead leads to the formation of a tilted smectic liquid crystal phase for the material featuring chiral difluorinated side chains, whereas irradiation with UV light results in the disappearance of the nanocylinders and the sole formation of HNFs for the azobenzene-containing material. Combined results of this experimental study reveal that in addition to controlling the rate of cooling, applied electric fields and UV irradiation can be used to expand the toolkit for structural and morphological control of suitably designed bent-core molecule-based structures at the nanoscale.
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Affiliation(s)
- Barış Sezgin
- Department
of Chemistry, Süleyman Demirel University, 32260 Isparta, Çünür, Turkey
- Advanced
Materials and Liquid Crystal Institute, Kent State University, Kent, Ohio 44242 United States
| | - Jiao Liu
- Advanced
Materials and Liquid Crystal Institute, Kent State University, Kent, Ohio 44242 United States
- Materials
Science Graduate Program, Kent State University, Kent, Ohio 44242 United States
| | - Diana P. N. Gonçalves
- Advanced
Materials and Liquid Crystal Institute, Kent State University, Kent, Ohio 44242 United States
- Department
of Chemistry and Biochemistry, Kent State
University, Kent, Ohio 44242 United States
| | - Chenhui Zhu
- Advanced
Light Source, Lawrence Berkeley National
Laboratory, Berkeley, California 94720 United States
| | - Tahir Tilki
- Department
of Chemistry, Süleyman Demirel University, 32260 Isparta, Çünür, Turkey
| | - Marianne E. Prévôt
- Advanced
Materials and Liquid Crystal Institute, Kent State University, Kent, Ohio 44242 United States
| | - Torsten Hegmann
- Advanced
Materials and Liquid Crystal Institute, Kent State University, Kent, Ohio 44242 United States
- Materials
Science Graduate Program, Kent State University, Kent, Ohio 44242 United States
- Department
of Chemistry and Biochemistry, Kent State
University, Kent, Ohio 44242 United States
- Brain Health
Research Institute, Kent State University, Kent, Ohio 44242 United States
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3
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Lee JJ, Choi SW. Effect of Nematogen Doping in Bent-Core Molecular Systems with a Helical Nanofilament and Dark Conglomerate. MATERIALS (BASEL, SWITZERLAND) 2023; 16:548. [PMID: 36676284 PMCID: PMC9861025 DOI: 10.3390/ma16020548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 12/31/2022] [Accepted: 01/04/2023] [Indexed: 06/17/2023]
Abstract
Two types of binary mixtures were prepared. One consisted of a calamitic nematogen and bent-core molecule with a helical nanofilament, whereas the other contained a calamitic nematogen and bent-core molecule with a dark conglomerate. The chiroptical features of these two mixtures were investigated using polarized optical microscopy and circular dichroism. In addition, X-ray diffraction analysis was performed on the two binary mixtures. The chiroptical features of the two mixtures were remarkably different. One mixture showed enhanced chiroptical features, whereas the other did not show chiroptical features. This method may help in distinguishing between helical nanofilaments and dark conglomerates which originate from bent-core molecular systems.
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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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5
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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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6
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Hockey-Stick Polycatenars: Network formation and transition from one dimensional to three-dimensional liquid crystalline phases. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.118613] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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7
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Kaur S, Begum N, Mohiuddin G, Kumar Pal S. Photo-Responsive Behavior of Azobenzene Based Polar Hockey-Stick-Shaped Liquid Crystals. Chemphyschem 2021; 22:1361-1370. [PMID: 33956388 DOI: 10.1002/cphc.202100215] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Revised: 05/05/2021] [Indexed: 11/08/2022]
Abstract
A study on the photoswitching behavior of azobenzene-based polar hockey-stick-shaped liquid crystals (HSLCs) has been presented. Two new series of five phenyl rings based polar HSLCs have been designed and synthesized. Solution state photoisomerization of the synthesized materials was investigated thoroughly via UV-visible and 1 H NMR spectroscopic techniques, whereas solid-state photochromic behavior was elucidated via physical color change of the materials, solid-state UV-visible study, powder XRD, and FE-SEM techniques. The materials exhibited decent photochromic behavior for different potential applications. The thermal phase behavior of the superstructural assembly has been characterized via polarizing optical microscopy (POM), differential scanning calorimetry (DSC), and temperature-dependent small and wide-angle X-ray scattering (SAXS/WAXS) studies. Depending upon the length of the terminal alkyl chain, nematic (N) and partially bilayer smectic A (SmAd ) phases were observed. DFT calculations revealed the favorable anti-parallel arrangement of the polar molecules that substantiate the formation of SmAd phase.
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Affiliation(s)
- Supreet Kaur
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector-81, Knowledge City, Manauli, 140306, India
| | - Nazma Begum
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector-81, Knowledge City, Manauli, 140306, India
| | - Golam Mohiuddin
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector-81, Knowledge City, Manauli, 140306, India
| | - Santanu Kumar Pal
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector-81, Knowledge City, Manauli, 140306, India
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8
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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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9
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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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10
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Reppe T, Poppe S, Tschierske C. Controlling Mirror Symmetry Breaking and Network Formation in Liquid Crystalline Cubic, Isotropic Liquid and Crystalline Phases of Benzil-Based Polycatenars. Chemistry 2020; 26:16066-16079. [PMID: 32652801 PMCID: PMC7756378 DOI: 10.1002/chem.202002869] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Indexed: 12/25/2022]
Abstract
Spontaneous development of chirality in systems composed of achiral molecules is important for new routes to asymmetric synthesis, chiral superstructures and materials, as well as for the understanding of the mechanisms of emergence of prebiotic chirality. Herein, it is shown that the 4,4'-diphenylbenzil unit is a universal transiently chiral bent building block for the design of multi-chained (polycatenar) rod-like molecules capable of forming a wide variety of helically twisted network structures in the liquid, the liquid crystalline (LC) and the crystalline state. Single polar substituents at the apex of tricatenar molecules support the formation of the achiral (racemic) cubic double network phase with Ia 3 ‾ d symmetry and relatively small twist along the networks. The combination of an alkyl chain with fluorine substitution leads to the homogeneously chiral triple network phase with I23 space group, and in addition, provides a mirror symmetry broken liquid. Replacing F by Cl or Br further increases the twist, leading to a short pitch double gyroid Ia 3 ‾ d phase, which is achiral again. The effects of the structural variations on the network structures, either leading to achiral phases or chiral conglomerates are analyzed.
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Affiliation(s)
- Tino Reppe
- Institute of ChemistryMartin Luther University Halle-WittenbergKurt-Mothes-Straße 206120HalleGermany
| | - Silvio Poppe
- Institute of ChemistryMartin Luther University Halle-WittenbergKurt-Mothes-Straße 206120HalleGermany
| | - Carsten Tschierske
- Institute of ChemistryMartin Luther University Halle-WittenbergKurt-Mothes-Straße 206120HalleGermany
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11
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Abstract
We prepared and studied bent-core liquid crystalline (LC) compounds based on 1,3-disubstituted benzene in a central part and azo-linkage attached directly to this bent core. We designed three structures and checked their mesogenic properties, as well as photosensitivity. We found that two studied compounds revealed columnar LC mesophases, which we transformed to the isotropic phase under the illumination of UV light. We concluded that only one type of structural motif was not mesogenic. For LC compounds, we established phases and phase transition temperatures based on differential scanning calorimetry (DSC) measurements and observations in a polarizing microscope. To confirm phase identification, X-ray studies were performed and structural parameters describing the columnar phases supplied.
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12
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Bazavan O, Saha SK, Paul MK, Dierking I. Chiral domain formation and spontaneous de-racemization in the Dark Conglomerate phase of a bent-core liquid crystal. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2020.113706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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13
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Lewandowski W, Vaupotič N, Pociecha D, Górecka E, Liz-Marzán LM. Chirality of Liquid Crystals Formed from Achiral Molecules Revealed by Resonant X-Ray Scattering. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e1905591. [PMID: 32529663 DOI: 10.1002/adma.201905591] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 03/14/2020] [Accepted: 03/16/2020] [Indexed: 05/21/2023]
Abstract
Intensive research on chiral liquid crystals (LCs) has been fueled by their actively tunable physicochemical properties and structural complexity, comparable to those of sophisticated natural materials. Herein, recent progress in the discovery of new classes of chiral LCs, enabled by a combination of nano- and macroscale investigations is reviewed. First, an overview is provided of liquid crystalline phases, made of chiral and achiral low-weight molecules, that exhibit chiral structure and/or chiral morphology. Then, recent progress in the discovery of new classes of chiral LCs, particularly enabled by the application of resonant X-ray scattering is described. It is shown that the method is sensitive to modulations of molecular orientation and therefore provides information hardly accessible by means of other techniques, such as the sense of helical structures or chirality transfer across length scales. Finally, a perspective is presented on the future scope, opportunities, and challenges in the field of chiral LCs, in particular related to nanocomposites.
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Affiliation(s)
- Wiktor Lewandowski
- Faculty of Chemistry, University of Warsaw, Pasteura 1 St., Warsaw, 02-093, Poland
| | - Nataša Vaupotič
- Department of Physics, University of Maribor, Koroška 160, Maribor, 2000, Slovenia
- Jozef Stefan Institute, Jamova 39, Ljubljana, 1000, Slovenia
| | - Damian Pociecha
- Faculty of Chemistry, University of Warsaw, Pasteura 1 St., Warsaw, 02-093, Poland
| | - Ewa Górecka
- Faculty of Chemistry, University of Warsaw, Pasteura 1 St., Warsaw, 02-093, Poland
| | - Luis M Liz-Marzán
- CIC biomaGUNE and CIBER-BBN, Paseo de Miramón 182, Donostia-San Sebastián, 20014, Spain
- Ikerbasque, Basque Foundation for Science, Bilbao, 48013, Spain
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14
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Kurata M, Yoshizawa A. The formation of a chiral supramolecular structure acting as a template for chirality transfer. Chem Commun (Camb) 2020; 56:8289-8292. [PMID: 32573614 DOI: 10.1039/d0cc02413a] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Spontaneous mirror symmetry breaking in self-assembled achiral trimers under a nonequilibrium state induces supramolecular chirality, which is stabilized by a polymer network to produce a homochiral material. Chirality is transferred to the polymer film in the course of polymerization of achiral reactive monomers on the surface.
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Affiliation(s)
- Misaki Kurata
- Department of Frontier Materials Chemistry, Graduate School of Science and Technology, Hirosaki University, 3 Bunkyo-cho, Hirosaki, Aomori 036-8561, Japan.
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15
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Reppe T, Poppe S, Cai X, Cao Y, Liu F, Tschierske C. Spontaneous mirror symmetry breaking in benzil-based soft crystalline, cubic liquid crystalline and isotropic liquid phases. Chem Sci 2020; 11:5902-5908. [PMID: 32874512 PMCID: PMC7446726 DOI: 10.1039/d0sc01396j] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2020] [Accepted: 04/29/2020] [Indexed: 01/06/2023] Open
Abstract
Benzil (diphenylethane-1,2-dione), which is a long known example for an achiral molecule crystallizing in a chiral space group, can also show mirror symmetry breaking in the fluid state if it is suitably functionalized. For some of the new benzil derivatives even three different subsequent mirror symmetry broken soft matter states with a chiral conglomerate structure can be observed. One is an isotropic liquid, the second one a cubic liquid crystal with a complex network structure and the third is a soft crystalline solid. Chirality develops by helical self-assembly combined with dynamic network formation, thus allowing macroscopic chirality synchronization. These achiral molecules, combining a transiently chiral bent core with multiple alkyl chains, provide a unique link between the mirror symmetry breaking phenomena observed for polycatenar and bent-core mesogens. The homogeneously chiral networks are of interest for application as chiral materials, and as templates for chiral recognition, separation and enantioselective catalysis.
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Affiliation(s)
- Tino Reppe
- Institute of Chemistry , Martin Luther University Halle-Wittenberg , Kurt-Mothes-Straße 2 , 06120 Halle , Germany .
| | - Silvio Poppe
- Institute of Chemistry , Martin Luther University Halle-Wittenberg , Kurt-Mothes-Straße 2 , 06120 Halle , Germany .
| | - Xiaoqian Cai
- State Key Laboratory for Mechanical Behaviour of Materials , Shaanxi International Research Center for Soft Matter , Xi'an Jiaotong University , Xi'an 710049 , P. R. China .
| | - Yu Cao
- State Key Laboratory for Mechanical Behaviour of Materials , Shaanxi International Research Center for Soft Matter , Xi'an Jiaotong University , Xi'an 710049 , P. R. China .
| | - Feng Liu
- State Key Laboratory for Mechanical Behaviour of Materials , Shaanxi International Research Center for Soft Matter , Xi'an Jiaotong University , Xi'an 710049 , P. R. China .
| | - Carsten Tschierske
- Institute of Chemistry , Martin Luther University Halle-Wittenberg , Kurt-Mothes-Straße 2 , 06120 Halle , Germany .
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16
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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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17
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Šmahel M, Poryvai A, Xiang Y, Pociecha D, Troha T, Novotná V, Svoboda J, Kohout M. Photosensitive bent-core nematic liquid crystals with various linking units in the side arms: Structure-properties relationships. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2020.112743] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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18
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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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19
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Cheng X, Miao T, Yin L, Ji Y, Li Y, Zhang Z, Zhang W, Zhu X. In Situ Controlled Construction of a Hierarchical Supramolecular Chiral Liquid‐Crystalline Polymer Assembly. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202001657] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Xiaoxiao Cheng
- State and Local Joint Engineering Laboratory for Novel Functional Polymeric MaterialsJiangsu Key Laboratory of Advanced Functional Polymer Design and ApplicationCollege of Chemistry, Chemical Engineering and Materials ScienceSoochow University Suzhou 215123 China
| | - Tengfei Miao
- State and Local Joint Engineering Laboratory for Novel Functional Polymeric MaterialsJiangsu Key Laboratory of Advanced Functional Polymer Design and ApplicationCollege of Chemistry, Chemical Engineering and Materials ScienceSoochow University Suzhou 215123 China
| | - Lu Yin
- State and Local Joint Engineering Laboratory for Novel Functional Polymeric MaterialsJiangsu Key Laboratory of Advanced Functional Polymer Design and ApplicationCollege of Chemistry, Chemical Engineering and Materials ScienceSoochow University Suzhou 215123 China
| | - Yujin Ji
- Institute of Functional Nano & Soft Materials (FUNSOM)Soochow University Suzhou 215123 China
| | - Youyong Li
- Institute of Functional Nano & Soft Materials (FUNSOM)Soochow University Suzhou 215123 China
| | - Zhengbiao Zhang
- State and Local Joint Engineering Laboratory for Novel Functional Polymeric MaterialsJiangsu Key Laboratory of Advanced Functional Polymer Design and ApplicationCollege of Chemistry, Chemical Engineering and Materials ScienceSoochow University Suzhou 215123 China
| | - Wei Zhang
- State and Local Joint Engineering Laboratory for Novel Functional Polymeric MaterialsJiangsu Key Laboratory of Advanced Functional Polymer Design and ApplicationCollege of Chemistry, Chemical Engineering and Materials ScienceSoochow University Suzhou 215123 China
| | - Xiulin Zhu
- State and Local Joint Engineering Laboratory for Novel Functional Polymeric MaterialsJiangsu Key Laboratory of Advanced Functional Polymer Design and ApplicationCollege of Chemistry, Chemical Engineering and Materials ScienceSoochow University Suzhou 215123 China
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20
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Cheng X, Miao T, Yin L, Ji Y, Li Y, Zhang Z, Zhang W, Zhu X. In Situ Controlled Construction of a Hierarchical Supramolecular Chiral Liquid-Crystalline Polymer Assembly. Angew Chem Int Ed Engl 2020; 59:9669-9677. [PMID: 32181944 DOI: 10.1002/anie.202001657] [Citation(s) in RCA: 78] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Revised: 02/25/2020] [Indexed: 11/09/2022]
Abstract
Hierarchical supramolecular chiral liquid-crystalline (LC) polymer assemblies are challenging to construct in situ in a controlled manner. Now, polymerization-induced chiral self-assembly (PICSA) is reported. Hierarchical supramolecular chiral azobenzene-containing block copolymer (Azo-BCP) assemblies were constructed with π-π stacking interactions occurring in the layered structure of Azo smectic phases. The evolution of chirality from terminal alkyl chain to Azo mesogen building blocks and further induction of supramolecular chirality in LC BCP assemblies during PICSA is achieved. Morphologies such as spheres, worms, helical fibers, lamellae, and vesicles were observed. The morphological transition had a crucial effect on the chiral expression of Azo-BCP assemblies. The supramolecular chirality of Azo-BCP assemblies destroyed by 365 nm UV irradiation can be recovered by heating-cooling treatment; this dynamic reversible achiral-chiral switching can be repeated at least five times.
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Affiliation(s)
- Xiaoxiao Cheng
- State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials, Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, China
| | - Tengfei Miao
- State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials, Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, China
| | - Lu Yin
- State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials, Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, China
| | - Yujin Ji
- Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou, 215123, China
| | - Youyong Li
- Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou, 215123, China
| | - Zhengbiao Zhang
- State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials, Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, China
| | - Wei Zhang
- State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials, Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, China
| | - Xiulin Zhu
- State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials, Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, China
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21
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Westphal E, Gallardo H, Poppe S, Prehm M, Tschierske C. Controlling the soft self-assembly of 1,3,4-oxadiazoles by carbosilane end-groups. J Mol Liq 2019. [DOI: 10.1016/j.molliq.2019.111362] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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22
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Foley L, Park W, Yang M, Carlson E, Korblova E, Yoon DK, Walba DM. Nanoconfinement of the Low-Temperature Dark Conglomerate: Structural Control from Focal Conics to Helical Nanofilaments. Chemistry 2019; 25:7438-7442. [PMID: 30957281 DOI: 10.1002/chem.201900653] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Indexed: 12/30/2022]
Abstract
The helical nanofilament (HNF) and low-temperature dark conglomerate (DC) liquid-crystal (LC) phases of bent-core molecules show the same local layer structure but present different bulk morphologies. The DC phase is characterized by the formation of nanoscale toric focal conics, whereas the HNF phase is constructed of bundles of twisted layers. Although the local layer structure is similar in both phases, materials that form these phases tend to form one morphology in preference to the other. Targeted control of the nanostructures would provide pathways to potential applications and insight into how conditions drive a specific phase formation. Here, W624, a compound known to form the DC phase is confined in nanometer scale channels of porous anodized aluminum oxide (AAO) membranes. Within each nanochannel, the DC phase is suppressed forming the HNF structure instead, indicating the nanoscale spatial limitation can control the phase structure of the DC phase.
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Affiliation(s)
- Lee Foley
- Department of Chemistry, University of Colorado Boulder, Soft Materials Research Center, Boulder, CO, 80309-0390, USA
| | - Wongi Park
- Graduate School of Nanoscience and Technology, Korea Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Minyong Yang
- Graduate School of Nanoscience and Technology, Korea Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Eric Carlson
- Department of Chemistry, University of Colorado Boulder, Soft Materials Research Center, Boulder, CO, 80309-0390, USA
| | - Eva Korblova
- Department of Chemistry, University of Colorado Boulder, Soft Materials Research Center, Boulder, CO, 80309-0390, USA
| | - Dong Ki Yoon
- Graduate School of Nanoscience and Technology, Korea Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea.,Department of Chemistry and KINC, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - David M Walba
- Department of Chemistry, University of Colorado Boulder, Soft Materials Research Center, Boulder, CO, 80309-0390, USA
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23
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Сhiral and Racemic Fields Concept for Understanding of the Homochirality Origin, Asymmetric Catalysis, Chiral Superstructure Formation from Achiral Molecules, and B-Z DNA Conformational Transition. Symmetry (Basel) 2019. [DOI: 10.3390/sym11050649] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The four most important and well-studied phenomena of mirror symmetry breaking of molecules were analyzed for the first time in terms of available common features and regularities. Mirror symmetry breaking of the primary origin of biological homochirality requires the involvement of an external chiral inductor (environmental chirality). All reviewed mirror symmetry breaking phenomena were considered from that standpoint. A concept of chiral and racemic fields was highly helpful in this analysis. A chiral gravitational field in combination with a static magnetic field (Earth’s environmental conditions) may be regarded as a hypothetical long-term chiral inductor. Experimental evidences suggest a possible effect of the environmental chiral inductor as a chiral trigger on the mirror symmetry breaking effect. Also, this effect explains a conformational transition of the right-handed double DNA helix to the left-handed double DNA helix (B-Z DNA transition) as possible DNA damage.
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24
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Alaasar M, Prehm M, Belau S, Sebastián N, Kurachkina M, Eremin A, Chen C, Liu F, Tschierske C. Polar Order, Mirror Symmetry Breaking, and Photoswitching of Chirality and Polarity in Functional Bent‐Core Mesogens. Chemistry 2019; 25:6362-6377. [DOI: 10.1002/chem.201806180] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 01/21/2019] [Indexed: 01/06/2023]
Affiliation(s)
- Mohamed Alaasar
- Institute of ChemistryMartin Luther University Halle-Wittenberg Kurt Mothes Str. 2 06120 Halle (Saale) Germany
- Department of Chemistry, Faculty of ScienceCairo University Giza Egypt
| | - Marko Prehm
- Institute of ChemistryMartin Luther University Halle-Wittenberg Kurt Mothes Str. 2 06120 Halle (Saale) Germany
| | - Sebastian Belau
- Department of Nonlinear Phenomena, Institute of PhysicsOtto von Guericke University Magdeburg Magdeburg Germany
| | - Nerea Sebastián
- Department of Nonlinear Phenomena, Institute of PhysicsOtto von Guericke University Magdeburg Magdeburg Germany
| | - Marharyta Kurachkina
- Department of Nonlinear Phenomena, Institute of PhysicsOtto von Guericke University Magdeburg Magdeburg Germany
| | - Alexey Eremin
- Department of Nonlinear Phenomena, Institute of PhysicsOtto von Guericke University Magdeburg Magdeburg Germany
| | - Changlong Chen
- State Key Laboratory for Mechanical Behavior of MaterialsXi'an Jiaotong University Xi'an 710049 P. R. China
| | - Feng Liu
- State Key Laboratory for Mechanical Behavior of MaterialsXi'an Jiaotong University Xi'an 710049 P. R. China
| | - Carsten Tschierske
- Institute of ChemistryMartin Luther University Halle-Wittenberg Kurt Mothes Str. 2 06120 Halle (Saale) Germany
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25
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Oikawa R, Sasaki H, Takanishi Y, Sagisaka M, Yamamoto J, Yoshizawa A. Linear symmetric liquid crystal trimers exhibiting supramolecular chiral architectures. SOFT MATTER 2019; 15:3179-3187. [PMID: 30892358 DOI: 10.1039/c9sm00250b] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We prepared a homologous series of achiral liquid crystal trimers (I-n) in which two phenylpyrimidine units and one biphenyl unit were connected via flexible spacers, and investigated the physical properties. All the trimers possessing odd-numbered methylene spacers exhibited soft crystalline chiral conglomerate phases. X-ray diffraction measurements reveal that they have an intercalated layer structure. On the other hand, the trimers possessing even-numbered spacers showed nematic and smectic C phases. We investigated the surface structures of odd-membered trimers in the soft crystalline phases using scanning electron microscopy. Trimers I-3 and I-5 were found to form cylindrical tubes, whereas trimers I-7, I-9 and I-11 toroidal pits. We discuss the formation of diverse supramolecular architectures in terms of the anisotropy of the chirality transfer.
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Affiliation(s)
- Ryuji Oikawa
- Department of Frontier Materials Chemistry, Graduate School of Science and Technology, Hirosaki University, 3 Bunkyo-cho, Hirosaki, 036-8561, Japan.
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26
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Oswald S, Seifert NA, Bohle F, Gawrilow M, Grimme S, Jäger W, Xu Y, Suhm MA. The Chiral Trimer and a Metastable Chiral Dimer of Achiral Hexafluoroisopropanol: A Multi-Messenger Study. Angew Chem Int Ed Engl 2019; 58:5080-5084. [PMID: 30767337 DOI: 10.1002/anie.201813881] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 01/10/2019] [Indexed: 01/05/2023]
Abstract
1,1,1,3,3,3-hexafluoro-propan-2-ol aggregates preferentially into an achiral dimer of achiral monomers, but the trimer is found to prefer three metastable chiral monomer units arranged into a strained OH⋅⋅⋅O hydrogen-bonded ring, which is reinforced by secondary CH⋅⋅⋅FC interactions. This is shown by a combination of infrared, microwave, and Raman spectroscopy in supersonic jet expansions and supported by high-level quantum chemical calculations. It involves an activation of the monomers by >15 kJ mol-1 , clearly driven by the much stronger hydrogen-bond interaction available to the gauche and even more to the cis monomer units.
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Affiliation(s)
- Sönke Oswald
- Institut für Physikalische Chemie, Georg-August Universität Göttingen, Tammannstraße 6, 37077, Göttingen, Germany
| | - Nathan A Seifert
- Department of Chemistry, University of Alberta, Edmonton, Alberta, T6G 2G2, Canada
| | - Fabian Bohle
- Mulliken Center for Theoretical Chemistry, Institut für Physikalische und Theoretische Chemie, Universität Bonn, Beringstraße 4, 53115, Bonn, Germany
| | - Maxim Gawrilow
- Institut für Physikalische Chemie, Georg-August Universität Göttingen, Tammannstraße 6, 37077, Göttingen, Germany
| | - Stefan Grimme
- Mulliken Center for Theoretical Chemistry, Institut für Physikalische und Theoretische Chemie, Universität Bonn, Beringstraße 4, 53115, Bonn, Germany
| | - Wolfgang Jäger
- Department of Chemistry, University of Alberta, Edmonton, Alberta, T6G 2G2, Canada
| | - Yunjie Xu
- Department of Chemistry, University of Alberta, Edmonton, Alberta, T6G 2G2, Canada
| | - Martin A Suhm
- Institut für Physikalische Chemie, Georg-August Universität Göttingen, Tammannstraße 6, 37077, Göttingen, Germany
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27
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Oswald S, Seifert NA, Bohle F, Gawrilow M, Grimme S, Jäger W, Xu Y, Suhm MA. The Chiral Trimer and a Metastable Chiral Dimer of Achiral Hexafluoroisopropanol: A Multi‐Messenger Study. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201813881] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Sönke Oswald
- Institut für Physikalische ChemieGeorg-August Universität Göttingen Tammannstraße 6 37077 Göttingen Germany
| | - Nathan A. Seifert
- Department of ChemistryUniversity of Alberta Edmonton Alberta T6G 2G2 Canada
| | - Fabian Bohle
- Mulliken Center for Theoretical ChemistryInstitut für Physikalische und Theoretische ChemieUniversität Bonn Beringstraße 4 53115 Bonn Germany
| | - Maxim Gawrilow
- Institut für Physikalische ChemieGeorg-August Universität Göttingen Tammannstraße 6 37077 Göttingen Germany
| | - Stefan Grimme
- Mulliken Center for Theoretical ChemistryInstitut für Physikalische und Theoretische ChemieUniversität Bonn Beringstraße 4 53115 Bonn Germany
| | - Wolfgang Jäger
- Department of ChemistryUniversity of Alberta Edmonton Alberta T6G 2G2 Canada
| | - Yunjie Xu
- Department of ChemistryUniversity of Alberta Edmonton Alberta T6G 2G2 Canada
| | - Martin A. Suhm
- Institut für Physikalische ChemieGeorg-August Universität Göttingen Tammannstraße 6 37077 Göttingen Germany
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28
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Yoshizawa A, Kurata M. Porous surface of an achiral trimer in the chiral conglomerate phase catalyzes a direct aldol reaction. NEW J CHEM 2019. [DOI: 10.1039/c9nj01913h] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The honeycomb-like porous surface consisting of linear trimer molecules catalyzes the direct aldol reaction of acetone with benzaldehyde at room temperature to give racemic β-hydroxyketone.
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Affiliation(s)
- Atsushi Yoshizawa
- Department of Frontier Materials Chemistry
- Graduate School of Science and Technology, Hirosaki University
- Aomori 036-8561
- Japan
| | - Misaki Kurata
- Department of Frontier Materials Chemistry
- Graduate School of Science and Technology, Hirosaki University
- Aomori 036-8561
- Japan
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29
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Sasaki H, Takanishi Y, Yamamoto J, Yoshizawa A. Photo-Driven Chirality Switching in a Dark Conglomerate Phase of an Achiral Liquid Crystal Trimer. ChemistrySelect 2018. [DOI: 10.1002/slct.201800067] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Haruna Sasaki
- Department of Frontier Materials Chemistry; Graduate School of Science and Technology; Hirosaki University; 3 Bunkyo-cho Hirosaki 036-8561 Japan
| | - Yoichi Takanishi
- Department of Physics; Graduate School of Science; Kyoto University; Oiwake-cho, Kitashirakawa, Sakyo-ku Kyoto 606-8502 Japan
| | - Jun Yamamoto
- Department of Physics; Graduate School of Science; Kyoto University; Oiwake-cho, Kitashirakawa, Sakyo-ku Kyoto 606-8502 Japan
| | - Atsushi Yoshizawa
- Department of Frontier Materials Chemistry; Graduate School of Science and Technology; Hirosaki University; 3 Bunkyo-cho Hirosaki 036-8561 Japan
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30
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Sasaki H, Takanishi Y, Yamamoto J, Yoshizawa A. Achiral flexible liquid crystal trimers exhibiting gyroid-like surfaces in chiral conglomerate phases. SOFT MATTER 2017; 13:6521-6528. [PMID: 28895612 DOI: 10.1039/c7sm01499f] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Chiral conglomerate phases have attracted much attention not only for the spontaneous mirror symmetry breaking but also for their nanostructures. We investigated both surface and bulk structures of a homologues series of an achiral liquid crystal trimer I-(n,m) exhibiting soft crystalline chiral conglomerate phases by atomic force microscopy (AFM) and scanning electron microscopy (SEM). The trimers were found to form bicontinuous networks. In particular, trimer I-(9,9) exhibited a single gyroid-like surface accompanying periodic distribution of dimples with a size of about 100 nm. It showed a sponge-like structure in the bulk of the material. The twist conformation of the flexible trimer I-(n,m) can cause layer deformation, which produces bicontinuous networks exhibiting optical activity.
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Affiliation(s)
- Haruna Sasaki
- Department of Frontier Materials Chemistry, Graduate School of Science and Technology, Hirosaki University, 3 Bunkyo-cho, Hirosaki, 036-8561, Japan.
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31
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Unsymmetrical achiral four ring hockey stick shaped mesogens based on 1,3,4-oxadiazole: Photophysical, mesogenic and DFT studies. J Mol Liq 2017. [DOI: 10.1016/j.molliq.2017.06.067] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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32
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Sasaki T, Takanishi Y, Yamamoto J, Yoshizawa A. A frustrated phase driven by competition among layer structures. SOFT MATTER 2017; 13:5194-5203. [PMID: 28671206 DOI: 10.1039/c7sm01090g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Using our designed ternary system consisting of a semiperfluorinated smectic liquid crystal and two nematic liquid crystals, we investigated their phase transition behaviour using polarizing optical microscopy, differential scanning calorimetry and X-ray diffraction. A mixture containing 20 mol% of the semiperfluorinated compound was found to exhibit the following unusual phase sequence: isotropic liquid - isotropic liquid + smectic A phase - nematic phase - unidentified frustrated phase (X) - modulated phase (Y) - modulated phase (Z). The frustrated phase showed a fan-shaped texture characteristic of a smectic phase, but no peak corresponding to the layer spacing was detected. No difference was found in the shearing stress between the high-temperature N phase and the frustrated phase, but electro-optical switching observed in the N phase was not detected in the frustrated phase. We discuss how the molecules organize the unusual phase transition behaviour.
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Affiliation(s)
- Takashi Sasaki
- Department of Frontier Materials Chemistry, Graduate School of Science and Technology, Hirosaki University, 3 Bunkyo-cho, Hirosaki, Aomori 036-8561, Japan.
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33
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Alaasar M, Prehm M, Poppe S, Tschierske C. Development of Polar Order by Liquid‐Crystal Self‐Assembly of Weakly Bent Molecules. Chemistry 2017; 23:5541-5556. [DOI: 10.1002/chem.201606035] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2016] [Indexed: 01/23/2023]
Affiliation(s)
- Mohamed Alaasar
- Institute of Chemistry Martin Luther University Halle-Wittenberg Kurt Mothes Str. 2 06120 Halle (Saale) Germany
- Department of Chemistry Faculty of Science Cairo University Giza Egypt
| | - Marko Prehm
- Institute of Chemistry Martin Luther University Halle-Wittenberg Kurt Mothes Str. 2 06120 Halle (Saale) Germany
| | - Silvio Poppe
- Institute of Chemistry Martin Luther University Halle-Wittenberg Kurt Mothes Str. 2 06120 Halle (Saale) Germany
| | - Carsten Tschierske
- Institute of Chemistry Martin Luther University Halle-Wittenberg Kurt Mothes Str. 2 06120 Halle (Saale) Germany
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34
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Kohout M, Alaasar M, Poryvai A, Novotná V, Poppe S, Tschierske C, Svoboda J. Photosensitive bent-core liquid crystals based on methyl substituted 3-hydroxybenzoic acid. RSC Adv 2017. [DOI: 10.1039/c7ra05632j] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Photosensitive liquid crystals are of contemporary interest not only from the scientific point of view but also for various applications. The chemical structure of materials is used to tune their mesomorphic and photosensitive properties.
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Affiliation(s)
- Michal Kohout
- Department of Organic Chemistry
- University of Chemistry and Technology Prague
- 166 28 Prague 6
- Czech Republic
| | - Mohamed Alaasar
- Institute of Chemistry
- Martin Luther University Halle-Wittenberg
- Halle-Saale
- Germany
- Department of Chemistry
| | - Anna Poryvai
- Department of Organic Chemistry
- University of Chemistry and Technology Prague
- 166 28 Prague 6
- Czech Republic
| | - Vladimíra Novotná
- Institute of Physics
- Academy of Science of the Czech Republic
- 182 21 Prague 9
- Czech Republic
| | - Silvio Poppe
- Institute of Chemistry
- Martin Luther University Halle-Wittenberg
- Halle-Saale
- Germany
| | - Carsten Tschierske
- Institute of Chemistry
- Martin Luther University Halle-Wittenberg
- Halle-Saale
- Germany
| | - Jiří Svoboda
- Department of Organic Chemistry
- University of Chemistry and Technology Prague
- 166 28 Prague 6
- Czech Republic
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35
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Buchs J, Vogel L, Janietz D, Prehm M, Tschierske C. Chirality Synchronization of Hydrogen-Bonded Complexes of Achiral N-Heterocycles. Angew Chem Int Ed Engl 2016; 56:280-284. [PMID: 27897356 DOI: 10.1002/anie.201609252] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Indexed: 01/13/2023]
Abstract
2,4-Diamino-6-phenyl-1,3,5-triazines carrying a single oligo(ethylene oxide) (EO) chain form an optically isotropic mesophase composed of a conglomerate of macroscopic chiral domains with opposite sense of chirality even though the constituent molecules are achiral. This mesophase was proposed to result from the helical packing of hydrogen-bonded triazine aggregates, providing long-range chirality synchronization. The results provide first evidence for macroscopic achiral symmetry breaking upon conglomerate formation in an amorphous isotropic phase formed by hydrogen-bonded associates of simple N-heterocycles that are related to prebiotic molecules.
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Affiliation(s)
- Jens Buchs
- Fraunhofer Institute for Applied Polymer Research, Geiselbergstrasse 69, 14476, Potsdam-Golm, Germany
| | - Laura Vogel
- Fraunhofer Institute for Applied Polymer Research, Geiselbergstrasse 69, 14476, Potsdam-Golm, Germany
| | - Dietmar Janietz
- Fraunhofer Institute for Applied Polymer Research, Geiselbergstrasse 69, 14476, Potsdam-Golm, Germany
| | - Marko Prehm
- Institute of Chemistry, Organic Chemistry, Martin-Luther-University Halle-Wittenberg, Kurt-Mothes-Strasse 2, 06120, Halle/Saale, Germany
| | - Carsten Tschierske
- Institute of Chemistry, Organic Chemistry, Martin-Luther-University Halle-Wittenberg, Kurt-Mothes-Strasse 2, 06120, Halle/Saale, Germany
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Buchs J, Vogel L, Janietz D, Prehm M, Tschierske C. Chirality Synchronization of Hydrogen‐Bonded Complexes of Achiral N‐Heterocycles. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201609252] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Jens Buchs
- Fraunhofer Institute for Applied Polymer Research Geiselbergstrasse 69 14476 Potsdam-Golm Germany
| | - Laura Vogel
- Fraunhofer Institute for Applied Polymer Research Geiselbergstrasse 69 14476 Potsdam-Golm Germany
| | - Dietmar Janietz
- Fraunhofer Institute for Applied Polymer Research Geiselbergstrasse 69 14476 Potsdam-Golm Germany
| | - Marko Prehm
- Institute of Chemistry, Organic Chemistry Martin-Luther-University Halle-Wittenberg Kurt-Mothes-Strasse 2 06120 Halle/Saale Germany
| | - Carsten Tschierske
- Institute of Chemistry, Organic Chemistry Martin-Luther-University Halle-Wittenberg Kurt-Mothes-Strasse 2 06120 Halle/Saale Germany
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Mandle RJ. The dependency of twist-bend nematic liquid crystals on molecular structure: a progression from dimers to trimers, oligomers and polymers. SOFT MATTER 2016; 12:7883-7901. [PMID: 27722733 DOI: 10.1039/c6sm01772j] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
This article gives an overview on recent developments concerning the twist-bend nematic phase. The twist-bend nematic phase has been discussed as the missing link between the uniaxial nematic mesophase (N) and the helical chiral nematic phase (N*). After an introduction discussing the key physical properties of the NTB phase and the methods used to identify the twist-bend nematic mesophase this review focuses on structure property relationships and molecular features that govern the incidence of this phase.
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Affiliation(s)
- Richard J Mandle
- Department of Chemistry, University of York, York, YO10 5DD, UK.
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Sreenilayam SP, Panarin YP, Vij JK, Panov VP, Lehmann A, Poppe M, Prehm M, Tschierske C. Spontaneous helix formation in non-chiral bent-core liquid crystals with fast linear electro-optic effect. Nat Commun 2016; 7:11369. [PMID: 27156514 PMCID: PMC4865739 DOI: 10.1038/ncomms11369] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Accepted: 03/21/2016] [Indexed: 01/31/2023] Open
Abstract
Liquid crystals (LCs) represent one of the foundations of modern communication and photonic technologies. Present display technologies are based mainly on nematic LCs, which suffer from limited response time for use in active colour sequential displays and limited image grey scale. Herein we report the first observation of a spontaneously formed helix in a polar tilted smectic LC phase (SmC phase) of achiral bent-core (BC) molecules with the axis of helix lying parallel to the layer normal and a pitch much shorter than the optical wavelength. This new phase shows fast (∼30 μs) grey-scale switching due to the deformation of the helix by the electric field. Even more importantly, defect-free alignment is easily achieved for the first time for a BC mesogen, thus providing potential use in large-scale devices with fast linear and thresholdless electro-optical response. Liquid crystals that consist of rod-like molecules currently dominate the materials used in industry for display and photonic applications. Here, the authors demonstrate electro-optic grey-scale switching based on the spontaneous formation of a short-pitch helix in a tilted smectic phase of achiral bent-core molecules.
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Affiliation(s)
- Sithara P Sreenilayam
- Department of Electronic and Electrical Engineering, Trinity College Dublin, The University of Dublin, Dublin 2, Ireland
| | - Yuri P Panarin
- Department of Electronic and Electrical Engineering, Trinity College Dublin, The University of Dublin, Dublin 2, Ireland.,School of Electrical and Electronic Engineering, Dublin Institute of Technology, Dublin 8, Ireland
| | - Jagdish K Vij
- Department of Electronic and Electrical Engineering, Trinity College Dublin, The University of Dublin, Dublin 2, Ireland
| | - Vitaly P Panov
- Department of Electronic and Electrical Engineering, Trinity College Dublin, The University of Dublin, Dublin 2, Ireland
| | - Anne Lehmann
- Department of Chemistry, Martin Luther University Halle-Wittenberg, D-06120 Halle, Germany
| | - Marco Poppe
- Department of Chemistry, Martin Luther University Halle-Wittenberg, D-06120 Halle, Germany
| | - Marko Prehm
- Department of Chemistry, Martin Luther University Halle-Wittenberg, D-06120 Halle, Germany
| | - Carsten Tschierske
- Department of Chemistry, Martin Luther University Halle-Wittenberg, D-06120 Halle, Germany
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Alaasar M, Prehm M, Tschierske C. Mirror symmetry breaking in fluorinated bent-core mesogens. RSC Adv 2016. [DOI: 10.1039/c6ra18482k] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
New fluorinated bent-core liquid crystals exhibiting helical nano-crystallite phases composed of chiral domains with opposite handedness and polar smcetic phases.
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Affiliation(s)
- Mohamed Alaasar
- Institute of Chemistry
- Martin Luther University Halle-Wittenberg
- D-06120 Halle (Saale)
- Germany
- Department of Chemistry
| | - Marko Prehm
- Institute of Chemistry
- Martin Luther University Halle-Wittenberg
- D-06120 Halle (Saale)
- Germany
| | - Carsten Tschierske
- Institute of Chemistry
- Martin Luther University Halle-Wittenberg
- D-06120 Halle (Saale)
- Germany
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