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Zellmann-Parrotta CO, Williams VE. Useful synthetic artifacts? The impact of ubiquitous linker-adjacent groups on the self-assembly of discotic dimers. SOFT MATTER 2024; 20:4504-4514. [PMID: 38804153 DOI: 10.1039/d4sm00425f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
Although discotic dimers commonly feature bulky ether substituents adjacent to the linking group, the impact of these chains on self-assembly remains unclear. A series of dibenzo[a,c]phenazine dimers with alkoxy groups ortho to the linker were prepared and their solution conformational dynamics and liquid crystalline properties examined. The presence of a methoxy substitutent adjacent to the bridging group increased the phase stability, whereas longer chains dramatically decreased clearing temperatures. NMR solution studies indicated that adjacent groups increased the preference of dimers to adopt unfolded conformers. DFT models indicated that the unfolded structures were nonplanar and hence less compatible with columnar ordering, leading to a destabilization of the mesophases.
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Affiliation(s)
| | - Vance E Williams
- Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, V5A 1S6, BC, Canada.
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Zellman CO, Williams VE. Semirigid discotic dimers: flexible but not flexible enough? Phys Chem Chem Phys 2023; 25:1363-1371. [PMID: 36537612 DOI: 10.1039/d2cp03706h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Two diastereomeric dibenzo[a,c]phenazine 1,2-cyclohexyl bridged diesters were prepared and their phase properties examined. While the trans dimer exhibited a broad columnar liquid crystal phase, the cis dimer was amorphous at all temperatures studied. This difference was attributed to the conformational dynamics of the two systems. NMR and DFT studies indicate that both dimers adopt folded and unfolded conformers in solution. While their folded geometries were similar, the trans dimer adopts an extended, largely planar structure, whereas the cis dimer is limited to non-planar unfolded structures and likely disrupts columnar ordering. Geometric constraints imposed by the cylcic linker were also important for columnar stability, with the trans dimer clearing 40 °C lower than the corresponding acyclic 2R,3R-butyl linked dimer, likely because the cyclohexyl group hinders π-π stacking in the unfolded conformation of the former.
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Affiliation(s)
- Carson O Zellman
- Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, V5A 1S6, BC, Canada.
| | - Vance E Williams
- Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, V5A 1S6, BC, Canada.
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Zellman CO, Williams VE. Stereochemistry, Conformational Dynamics, and the Stability of Liquid Crystal Phases. J Org Chem 2021; 86:15076-15084. [PMID: 34672594 DOI: 10.1021/acs.joc.1c01626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Although discotic liquid crystal dimers have been widely targeted as organic semiconductors and as LC-glass formers, the role of conformational dynamics on the self-assembly of these flexible mesogens remains poorly understood. In an effort to probe this effect, we investigated the impact of linker stereochemistry on the phase behavior of discotic liquid crystalline dimers. Diastereomeric dibenzo[a,c]phenazine diesters were prepared from (2R,3R)- and meso-2,3-butanediol. While both dimers form columnar phases, the meso-isomer had a clearing temperature (Tc) that was 31 °C higher than that of its chiral diastereomer. Conformational analysis via DFT calculations, 1H-NMR, and DOSY experiments indicated that both compounds adopt predominantly extended conformations but that the meso-dimer shows a stronger preference to unfold in solution. To probe how conformation alters phase stability, we prepared derivatives in which catechol and hydroquinone act as rigid linkers that lock the dimers in a folded or an extended conformation, respectively. The diester of hydroquinone possessed a Tc that was nearly 100 °C higher than the catechol derivative, consistent with a model where extended conformations stabilize the LC phase. Extended dimers also exhibited higher transition enthalpies at the Tc, an indication that their columnar phases are more ordered than folded structures.
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Affiliation(s)
- Carson O Zellman
- Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada
| | - Vance E Williams
- Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada
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Morillo N, Martínez-Haya B, Cuetos A. Tailoring the phase diagram of discotic mesogens. SOFT MATTER 2021; 17:8693-8704. [PMID: 34519327 DOI: 10.1039/d1sm00624j] [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 computational modelling of discotic molecules is a central topic in colloid science that is key for the smart design of a broad range of modern functional materials. This work lays out a versatile interaction model capable of exposing the rich mesogenic behaviour of discotics. A single coarse-grained spheroplatelet core framework is employed to generate a variety of pair interaction anisotropy classes, favouring specific relative orientations of the particles (stacked, side-side, crossed, T-shaped). This paves the way for the systematic tailoring of the discotic liquid phase diagram. Monte Carlo simulations are performed for an ensemble of case studies to illustrate the correlation between the topology of the interaction and the formation of stable nematic, smectic and columnar phases, as well as of less common cubatic, uniaxial and biaxial columnar domains.
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Affiliation(s)
- Neftalí Morillo
- Department of Theoretical Physics, Universidad Complutense de Madrid, Avda. de la Complutense S/N, 28040 Madrid, Spain.
| | - Bruno Martínez-Haya
- Department of Physical, Chemical and Natural Systems, Pablo de Olavide University, 41013 Sevilla, Spain
| | - Alejandro Cuetos
- Department of Physical, Chemical and Natural Systems, Pablo de Olavide University, 41013 Sevilla, Spain
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Znoiko SA, Akopova OB, Bumbina NV, Usoltseva NV, Maizlish VE, Shaposhnikov GP, Abramov IG. Nucleophilic substitution in 4-bromo-5-nitrophthalodinitrile: XI. Preparation, properties, and prediction of mesomorphism in mixed-substituted phthalocyanines containing aryloxy and benzotriazole fragments. RUSS J GEN CHEM+ 2014. [DOI: 10.1134/s1070363214040185] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Saper G, Kler S, Asor R, Oppenheim A, Raviv U, Harries D. Effect of capsid confinement on the chromatin organization of the SV40 minichromosome. Nucleic Acids Res 2013; 41:1569-80. [PMID: 23258701 PMCID: PMC3561987 DOI: 10.1093/nar/gks1270] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Revised: 10/26/2012] [Accepted: 11/05/2012] [Indexed: 01/10/2023] Open
Abstract
Using small-angle X-ray scattering, we determined the three-dimensional packing architecture of the minichromosome confined within the SV40 virus. In solution, the minichromosome, composed of closed circular dsDNA complexed in nucleosomes, was shown to be structurally similar to cellular chromatin. In contrast, we find a unique organization of the nanometrically encapsidated chromatin, whereby minichromosomal density is somewhat higher at the center of the capsid and decreases towards the walls. This organization is in excellent agreement with a coarse-grained computer model, accounting for tethered nucleosomal interactions under viral capsid confinement. With analogy to confined liquid crystals, but contrary to the solenoid structure of cellular chromatin, our simulations indicate that the nucleosomes within the capsid lack orientational order. Nucleosomes in the layer adjacent to the capsid wall, however, align with the boundary, thereby inducing a 'molten droplet' state of the chromatin. These findings indicate that nucleosomal interactions suffice to predict the genome organization in polyomavirus capsids and underscore the adaptable nature of the eukaryotic chromatin architecture to nanoscale confinement.
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Affiliation(s)
- Gadiel Saper
- Institute of Chemistry, The Hebrew University, Jerusalem 91904, Israel, The Fritz Haber Research Center, The Hebrew University, Jerusalem 91904, Israel and Department of Hematology, Hebrew University–Hadassa Medical School, Jerusalem 91120, Israel
| | - Stanislav Kler
- Institute of Chemistry, The Hebrew University, Jerusalem 91904, Israel, The Fritz Haber Research Center, The Hebrew University, Jerusalem 91904, Israel and Department of Hematology, Hebrew University–Hadassa Medical School, Jerusalem 91120, Israel
| | - Roi Asor
- Institute of Chemistry, The Hebrew University, Jerusalem 91904, Israel, The Fritz Haber Research Center, The Hebrew University, Jerusalem 91904, Israel and Department of Hematology, Hebrew University–Hadassa Medical School, Jerusalem 91120, Israel
| | - Ariella Oppenheim
- Institute of Chemistry, The Hebrew University, Jerusalem 91904, Israel, The Fritz Haber Research Center, The Hebrew University, Jerusalem 91904, Israel and Department of Hematology, Hebrew University–Hadassa Medical School, Jerusalem 91120, Israel
| | - Uri Raviv
- Institute of Chemistry, The Hebrew University, Jerusalem 91904, Israel, The Fritz Haber Research Center, The Hebrew University, Jerusalem 91904, Israel and Department of Hematology, Hebrew University–Hadassa Medical School, Jerusalem 91120, Israel
| | - Daniel Harries
- Institute of Chemistry, The Hebrew University, Jerusalem 91904, Israel, The Fritz Haber Research Center, The Hebrew University, Jerusalem 91904, Israel and Department of Hematology, Hebrew University–Hadassa Medical School, Jerusalem 91120, Israel
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Lamarra M, Muccioli L, Orlandi S, Zannoni C. Temperature dependence of charge mobility in model discotic liquid crystals. Phys Chem Chem Phys 2012; 14:5368-75. [DOI: 10.1039/c2cp23178f] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Gao Y, Slattery JM, Bruce DW. Columnar thermotropic mesophases formed by dimeric liquid-crystalline ionic liquids exhibiting large mesophase ranges. NEW J CHEM 2011. [DOI: 10.1039/c1nj20715f] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Imrie CT, Henderson PA. Liquid crystal dimers and higher oligomers: between monomers and polymers. Chem Soc Rev 2007; 36:2096-124. [PMID: 17982523 DOI: 10.1039/b714102e] [Citation(s) in RCA: 442] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The underlying theme of this Critical Review is the relationship between molecular structure and liquid crystalline behaviour in a class of materials referred to as liquid crystal oligomers. For the purposes of this review, a liquid crystal oligomer will be defined as consisting of molecules composed of semi-rigid mesogenic units connected via flexible spacers. Much of the review will be devoted to structure-property relationships in the simplest oligomers, namely dimers, in which just two mesogenic units are connected by a single spacer. Along the way we will see how this molecular architecture has been exploited to address issues in a range of quite different areas and has given rise to potential applications for these materials. On the whole, only compounds in which the mesogenic units are linked essentially in a linear fashion will be considered while structures such as liquid crystal dendrimers and tetrapodes fall outside the scope of this review. The review will be of interest not only to scientists working directly in this area but in particular to those interested in understanding the relationships between structure and properties in polymers, and those designing materials for new applications.
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Affiliation(s)
- Corrie T Imrie
- Chemistry, School of Natural and Computing Sciences, University of Aberdeen, Meston Building, Aberdeen, UK AB24 3UE.
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