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Liquid-crystalline 1,4-benzoquinone derivative: Self-assembling behavior and redox properties. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.116636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Reddy MG, Lobo NP, Roy A, Ramanathan KV, Narasimhaswamy T. Strikingly different molecular organization and molecular order of tetracatenar mesogens in columnar mesophases revealed by XRD and 13C NMR. Phys Chem Chem Phys 2020; 22:23986-23997. [PMID: 33073796 DOI: 10.1039/d0cp03933k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
For a successful design of functional mesogens, it is paramount to understand factors that contribute to molecular organisation such as molecular shape, the non-covalent interactions of the constituent moieties as well as nanosegregation of incompatible molecular parts. In this study on four tetracatenar mesogens, we show that by a slight change in the length of the terminal chain, the molecular organization changes from lamellar to columnar phase and that the orientational order experiences profound change between the lamellar, the center rectangular columnar and the hexagonal columnar mesophases. We consider here, mesogens that exhibit lamellar and columnar mesophases with five phenyl rings in the central rod-like core which are subjected to XRD and high resolution solid state 13C NMR investigations in their mesophases. The XRD studies indicate that the lower homologs exhibit a lamellar mesophase while the higher homologs show either a centre rectangular columnar phase or a 2D hexagonal columnar mesophase. 13C NMR investigations reveal interesting and strikingly different molecular orientations in each of these phases. For example, values of order parameters of one of the phenyl rings in the core region of the mesogens vary from 0.75 and 0.77 for the lamellar mesogens to 0.45 and 0.17 for the centre rectangular columnar and the hexagonal columnar mesogens respectively. While these values indicate that the mesogenic molecules are oriented along the magnetic field as expected in the lamellar phases, the very low order parameter in the hexagonal columnar phase arises due to molecules distributed azimuthally in layers and undergoing motion about the columnar axis which itself is oriented orthogonal to the magnetic field. Such cutting edge information extracted from the combined use of XRD and 13C NMR studies on tetracatenar mesogens is expected to be of significant use for the study of π-conjugated polycatenar systems where functional properties depend on the molecular orientation and order.
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Affiliation(s)
- M Guruprasad Reddy
- Polymer Science and Technology, CSIR-Central Leather Research Institute, Adyar, Chennai 600020, India.
| | - Nitin P Lobo
- Centre for Analysis, Testing, Evaluation & Reporting Services (CATERS), CSIR-Central Leather Research Institute, Adyar, Chennai 600020, India
| | - Arun Roy
- Soft Condensed Matter, Raman Research Institute, Bangalore, 560080, India.
| | - K V Ramanathan
- NMR Research Centre, Indian Institute of Science, Bangalore, 560012, India.
| | - T Narasimhaswamy
- Polymer Science and Technology, CSIR-Central Leather Research Institute, Adyar, Chennai 600020, India.
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Lobo NP, Ramanathan KV, Narasimhaswamy T. 13 C NMR investigations of molecular order of rod-like, bent-core, and thiophene mesogens. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2020; 58:988-1009. [PMID: 31770458 DOI: 10.1002/mrc.4972] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 11/09/2019] [Accepted: 11/13/2019] [Indexed: 06/10/2023]
Abstract
In this review, methods to obtain the orientational order of topologically variant molecular mesogens using by one- and two-dimensional (2D) solid-state 13 C nuclear magnetic resonance (NMR) spectroscopy are described. Besides 13 C chemical shifts, the 13 C─1 H dipolar couplings measured from 2D-separated local field (SLF) technique are used for computing the order parameters of a variety of mesogens. The investigated molecules are composed of a variable number of rings in the core, that is, core ranging from simply one ring to five rings. Among the mesogens investigated, a special focus has been placed on mesogens with thiophene rings, which are gaining popularity as liquid crystalline organic semiconductors. The replacement of a phenyl ring by thiophene in the core has a dramatic influence on molecular topology, as observed from the measured order parameters. The review highlights the advantages of the 2D SLF method for understanding the local dynamics and for mapping the topology of mesogens through the measured order parameters. SLF NMR studies of as many as 24 molecular mesogens that vary in terms of the molecular structure as well as topology are covered in the review. Order parameters of the rings have been estimated from the 13 C─1 H dipolar couplings in the nematic, smectic A, smectic C, and tilted hexatic phases as well as in B1 and B2 mesophases of various mesogens. It is anticipated that, in the years to come, the 2D SLF method would provide advanced molecular information on structurally complex mesogens that are emerging in liquid crystal science through the incessant efforts of synthetic chemists. The mini review covers the orientational order of topologically variant molecular mesogens determined by 1D and 2D solid-state 13 C NMR spectroscopy. Accordingly, rod-like, bent-core, and thiophene mesogens were subjected to 2D SLF measurements to get the order parameters from which the topology was established. The replacement of phenyl ring by thiophene and its influence on order parameters as well as on molecular topology is also discussed.
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Affiliation(s)
- Nitin P Lobo
- Inorganic and Physical Chemistry, CSIR-Central Leather Research Institute, Chennai, India
| | - K V Ramanathan
- NMR Research Centre, Indian Institute of Science, Bangalore, India
| | - T Narasimhaswamy
- Polymer Science and Technology, CSIR-Central Leather Research Institute, Chennai, India
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Reddy MG, Lobo NP, Ramanathan KV, Narasimhaswamy T. Molecular Order of Topologically Variant Flexible Mesogens by 13C Nuclear Magnetic Resonance. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:12620-12631. [PMID: 32993293 DOI: 10.1021/acs.langmuir.0c02182] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
13C nuclear magnetic resonance investigations in the nematic phase of mesogens comprising a rod-like core with three phenyl rings connected to a fourth phenyl ring via a flexible spacer are reported. The molecules are abbreviated as monomer, dimer, and trimer as they comprised one, two, and three pairs of core and spacer combinations linked to ring IV, respectively. Hot-stage optical polarizing microscopy and differential scanning calorimetry studies confirmed that all of them exhibit an enantiotropic nematic phase with additional monotropic or enantiotropic smectic mesophases. Large values of 13C-1H dipolar couplings of the order of 11 kHz are observed for all the cases for the terminal carbon C1 of the core unit. These high values indicated that the corresponding CH vector is collinear with the long axis of the molecule, which itself is aligned parallel to the magnetic field. In contrast, the terminal carbon of the ring IV (C19/C17) exhibits a relatively smaller value in the range of 2.0-2.5 kHz, reflecting the divergent local dynamics at different sections of the mesogens. The orientational order parameters of the phenyl rings computed from the 13C-1H dipolar couplings have been used to obtain the conformation of the mesogens in the nematic phase. It is concluded that the dimer and trimer exhibit C2 and C3 symmetry with the ring IV connected by spacers tilted away from the symmetry axis by 35.9 and 90° for the two cases, respectively. This leads to the interesting tripod-like molecular shape for the trimer in the nematic phase rather than the planar representation of the λ shape.
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Affiliation(s)
- Mandadhi Guruprasad Reddy
- Polymer Science and Technology, CSIR-Central Leather Research Institute, Adyar, Chennai 600020, India
| | - Nitin P Lobo
- Centre for Analysis, Testing, Evaluation & Reporting Services (CATERS) CSIR-Central Leather Research Institute, Adyar, Chennai 600020, India
| | | | - Tanneru Narasimhaswamy
- Polymer Science and Technology, CSIR-Central Leather Research Institute, Adyar, Chennai 600020, India
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Reddy GSM, Narasimhaswamy T, Kumar BVNP, Raju KM. Structural Assignment of Side Chain Liquid Crystalline Monomer and Polymer by 1-D and 2-D Solution NMR Studies. INTERNATIONAL JOURNAL OF POLYMER ANALYSIS AND CHARACTERIZATION 2015. [DOI: 10.1080/1023666x.2015.975023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Lobo NP, Das BB, Narasimhaswamy T, Ramanathan KV. Molecular topology of three ring nematogens from 13C–1H dipolar couplings. RSC Adv 2014. [DOI: 10.1039/c4ra03963g] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
A facile way of estimating the order parameter and the molecular orientation from 13C–1H dipolar couplings for three ring based nematogens with a terminal C–H vector.
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Affiliation(s)
- Nitin P. Lobo
- Department of Physics
- Indian Institute of Science
- Bangalore 560012, India
| | - Bibhuti B. Das
- Department of Physics
- Indian Institute of Science
- Bangalore 560012, India
| | - T. Narasimhaswamy
- Polymer Laboratory
- CSIR-Central Leather Research Institute
- Chennai 600 020, India
| | - K. V. Ramanathan
- NMR Research Centre
- Indian Institute of Science
- Bangalore 560012, India
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Shanker G, Shankar Rao D, Krishna Prasad S, Yelamaggad C. Synthesis and characterization of supramolecular optically active bisamides derived from amino acids. Tetrahedron 2012. [DOI: 10.1016/j.tet.2012.05.070] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Shanker G, Rao DSS, Prasad SK, Yelamaggad CV. Self-assembly of chiral hexacatenar-bisamides into a columnar structure. RSC Adv 2012. [DOI: 10.1039/c1ra00684c] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Pettinari C, Masciocchi N, Pandolfo L, Pucci D. Tuning the Functional Properties of Metal Complexes Containing Polytopic Heteroaromatic Nitrogen Ligands. Chemistry 2010; 16:1106-23. [PMID: 20020517 DOI: 10.1002/chem.200901923] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Claudio Pettinari
- Department of Chemical Sciences, University of Camerino, Via S. Agostino 1, 62032 Camerino, Italy.
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Li CZ, Matsuo Y, Nakamura E. Luminescent Bow-Tie-Shaped Decaaryl[60]fullerene Mesogens. J Am Chem Soc 2009; 131:17058-9. [DOI: 10.1021/ja907908m] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Chang-Zhi Li
- Nakamura Functional Carbon Cluster Project, ERATO, Japan Science and Technology Agency (JST), Hongo, Bunkyo-ku, Tokyo 113-0033, Japan, and Department of Chemistry, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Yutaka Matsuo
- Nakamura Functional Carbon Cluster Project, ERATO, Japan Science and Technology Agency (JST), Hongo, Bunkyo-ku, Tokyo 113-0033, Japan, and Department of Chemistry, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Eiichi Nakamura
- Nakamura Functional Carbon Cluster Project, ERATO, Japan Science and Technology Agency (JST), Hongo, Bunkyo-ku, Tokyo 113-0033, Japan, and Department of Chemistry, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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Crispini A, Ghedini M, Pucci D. Functional properties of metallomesogens modulated by molecular and supramolecular exotic arrangements. Beilstein J Org Chem 2009; 5:54. [PMID: 20126634 PMCID: PMC2813712 DOI: 10.3762/bjoc.5.54] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2009] [Accepted: 10/02/2009] [Indexed: 11/23/2022] Open
Abstract
New concepts for the synthesis of metallomesogens have been recently developed in order to use the metal centre as a scaffold for grafting different functionalities and inducing non-conventional shapes and properties in the resulting complexes. Our strategy was based on the synthesis of mesogenic coordination complexes whose molecular architectures are controlled by the modulation of different and tunable molecular motifs: the nature of the metal ion and the surrounding ligands as central unit, the number of flexible chains at the periphery, and the nature of counter-ions in ionic complexes. The appropriate choice of molecular construction motifs allows control at global architectures and induces pre-selected properties from the level of single molecule to supramolecular network, confirming that metal coordination provides a helpful tool for obtaining multifunctional soft materials.
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Affiliation(s)
- Alessandra Crispini
- Centro di Eccellenza CEMIF.CAL-LASCAMM, CR-INSTM Unità della Calabria, Dipartimento di Scienze Farmaceutiche, Università della Calabria, Edificio Polifunzionale, Arcavacata di Rende (CS), 87036, Italy
| | - Mauro Ghedini
- Centro di Eccellenza CEMIF.CAL-LASCAMM, CR-INSTM Unità della Calabria, Dipartimento di Chimica, Università della Calabria, Via P. Bucci Cubo 14C, Arcavacata di Rende (CS), 87036, Italy
| | - Daniela Pucci
- Centro di Eccellenza CEMIF.CAL-LASCAMM, CR-INSTM Unità della Calabria, Dipartimento di Chimica, Università della Calabria, Via P. Bucci Cubo 14C, Arcavacata di Rende (CS), 87036, Italy
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Nanostructured columnar and cubic liquid-crystalline assemblies consisting of unconventional rigid mesogens based on triphenylmethanes. Tetrahedron 2008. [DOI: 10.1016/j.tet.2008.06.034] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Tsakova V. How to affect number, size, and location of metal particles deposited in conducting polymer layers. J Solid State Electrochem 2008. [DOI: 10.1007/s10008-007-0494-y] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Pucci D, Aiello I, Bellusci A, Crispini A, De Franco I, Ghedini M, La Deda M. A “jellyfish” shaped green emitting gallium(iii)-containing metallomesogen. Chem Commun (Camb) 2008:2254-6. [DOI: 10.1039/b800030a] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Bates MA. Coarse grained models for flexible liquid crystals: Parameterization of the bond fluctuation model. J Chem Phys 2004; 120:2026-33. [PMID: 15268338 DOI: 10.1063/1.1634551] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We extend the bond fluctuation model, originally devised to investigate polymer systems, to contain anisotropic interactions suitable for the simulation of large flexible molecules such as liquid crystalline polymers and dendrimers. This extended model coarse grains the interaction between the flexible chains at a similar level of detail to the mesogenic units. Suitable interaction parameters are obtained by performing trial simulations on a low molar mass liquid crystalline system. The phase diagram of this system is determined as a function of the molecular stiffness. The nematic to isotropic transition temperature is found to increase with increasing stiffness.
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Affiliation(s)
- Martin A Bates
- Department of Chemistry, University of Southampton, Southampton SO17 1BJ, United Kingdom.
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Abstract
In this article, the search for the elusive biaxial nematic phase (NB) in liquid crystals is considered. The structure of the phase is described along with theoretical and computational work which suggests how it might be realised. An overview of the work of the Exeter group in this area is then given showing the different approaches adopted and illustrating how one of these has led to a new type of amphiphilicity based on shape.
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Affiliation(s)
- Duncan W Bruce
- Department of Chemistry, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK.
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Urata K. Unique block molecules based on glycerol skeleton as C-3 building blocks for liquid crystals formation by self-assembly and their future potential for the“nano-chemistry”. EUR J LIPID SCI TECH 2003. [DOI: 10.1002/ejlt.200300814] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Takaguchi Y, Tajima T, Yanagimoto Y, Tsuboi S, Ohta K, Motoyoshiya J, Aoyama H. Self-assembly and regioselective photodimerization of anthracene having a dendritic substituent. Org Lett 2003; 5:1677-9. [PMID: 12735750 DOI: 10.1021/ol0343109] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
[reaction: see text] Thermotropic liquid crystallinity can be induced for an anthracene having a dendritic substituent. The photodimerization reaction of an anthracene moiety in the smectic phase proceeded quantitatively and regioselectively.
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Affiliation(s)
- Yutaka Takaguchi
- Faculty of Environmental Science and Technology, Okayama University, Okayama, Okayama 700-8530, Japan.
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Eichhorn SH, Paraskos AJ, Kishikawa K, Swager TM. The interplay of bent-shape, lateral dipole and chirality in thiophene based di-, tri-, and tetracatenar liquid crystals. J Am Chem Soc 2002; 124:12742-51. [PMID: 12392421 DOI: 10.1021/ja0268027] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A range of mesogenic molecules varying in both bend angle and strength of lateral dipole were synthesized, and their phase behavior was characterized by polarizing microscopy, thermal analysis, X-ray diffraction, and electrooptical measurements. We find the general destabilization of the liquid crystallinity caused by strong lateral dipolar groups and the bent molecular shape are off-set in mesomorphic tetracatenars, which display stable nematic, smectic, columnar, and cubic mesophases. The broad mesomorphism of the tetracatenars containing lateral dipoles and their incompatibility with chiral induction are explained by considering that loosely correlated dimers exist within the mesophases. Chiral mesophases of derivatives with strong lateral dipoles were achieved by attaching fewer or different side chains to each end of the mesogen.
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Affiliation(s)
- S Holger Eichhorn
- Department of Chemistry and Center for Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge 02139, USA
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