1
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Patra A, Shah A, Singh DP, Roy A, Kumar S. Novel Self-Assembling Supramolecular Phenanthro[9,10-a]phenazine Discotic Liquid Crystals: Synthesis, Characterization and Charge Transport Studies. Chem Asian J 2024:e202400542. [PMID: 38940412 DOI: 10.1002/asia.202400542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2024] [Revised: 06/27/2024] [Accepted: 06/28/2024] [Indexed: 06/29/2024]
Abstract
The incorporation of heteroatoms in the chemical structure of organic molecules has been identified as analogous to the doping process adopted in silicon semiconductors to influence the nature of charge carriers. This strategy has been an eye-opener for material chemists in synthesizing new materials for optoelectronic applications. Phenanthro[9,10-a]phenazine-based mesogens have been synthesized via a cyclo-condensation pathway involving triphenylene-based diketone and o-phenyl diamines. The incorporation of phenazine moiety as discussed in this paper, alters the symmetric nature of the triphenylene. The phenanthro[9,10-a]phenazine-based mesogens exhibit hole mobility in the order of 10-4 cm2/Vs as measured by the space-charge limited current (SCLC) technique. The current density in the SCLC device increases with increasing temperature which indicates that the charge transport is associated with the thermally activated hopping process. This report attempts to elucidate the self-organization of asymmetric phenanthro[9,10-a] phenazine in the supramolecular liquid crystalline state and their potential for the fabrication of high-temperature optoelectronic devices. However, the low charge carrier mobility can be one of the challenges for device performance.
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Affiliation(s)
- Alakananda Patra
- Soft Condensed Matter, Raman Research Institute, C. V. Raman Avenue, Bengaluru, 560080, India
| | - Asmita Shah
- Unité de Dynamique et Structure des Matériaux Moléculaires (UDSMM), Université du Littoral Côte d'Opale (ULCO), UR 4476, 62228, Calais cedex, France
| | - Dharmendra Pratap Singh
- Unité de Dynamique et Structure des Matériaux Moléculaires (UDSMM), Université du Littoral Côte d'Opale (ULCO), UR 4476, 62228, Calais cedex, France
| | - Arun Roy
- Soft Condensed Matter, Raman Research Institute, C. V. Raman Avenue, Bengaluru, 560080, India
| | - Sandeep Kumar
- Soft Condensed Matter, Raman Research Institute, C. V. Raman Avenue, Bengaluru, 560080, India
- Department of Chemistry, Nitte Meenakshi Institute of Technology, Yelahanka, Bangalore, 560064, India
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2
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Dabhi RC, Sharma VS, Arya PS, Patel UP, Shrivastav PS, Maru JJ. Coumarin functionalized dimeric mesogens for promising anticoagulant activity: Tuning of liquid crystalline property. J Mol Struct 2023. [DOI: 10.1016/j.molstruc.2023.135336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/14/2023]
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3
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Rathod SL, Sharma VS, Patel KR, Mali HA, Shrivastav PS, Parekh HM. Lower rim functionalized bowl-shaped resorcin[4]arene with alkyl arms: a simplified approach to build supramolecular liquid crystals. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2022.134571] [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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4
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Rathod SL, Sharma VS, Sharma AS, Athar M, Shrivastav PS, Parekh HM. “Blue light-emitting Quinoline armed Thiacalix [4]arene 3D-scaffold: a Systematic Platform to construct Fluorescent Liquid Crystals with Bio-imaging Applications”. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2022.133830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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5
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Sharma VS, Shah PA, Sharma AS, Subba Rao Ganga V, Shrivastav PS, Prajapat V. Upper/lower rim functionalized calixarene based AIE-active liquid crystals with self-assembly behavior: Photophysical and electrochemical studies. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2021.118047] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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6
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Sharma VS, Sharma AS, Worthington SJB, Shah PA, Shrivastav PS. Columnar self-assembly, electrochemical and luminescence properties of basket-shaped liquid crystalline derivatives of Schiff-base-moulded p-tert-butyl-calix[4]arene. NEW J CHEM 2020. [DOI: 10.1039/d0nj04148c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A new family of blue-light emitting supramolecular basket-shaped liquid crystalline compounds based on p-tert-butyl-calix[4]arene core to form self-assembly and columnar hexagonal phase.
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Affiliation(s)
- Vinay S. Sharma
- Department of Chemistry
- Faculty of Basic and Applied Science
- Madhav University
- Sirohi
- India
| | - Anuj S. Sharma
- Department of Chemistry
- School of Science
- Gujarat University
- Ahmedabad
- India
| | | | - Priyanka A. Shah
- Department of Chemistry
- School of Science
- Gujarat University
- Ahmedabad
- India
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7
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Sharma VS, Sharma AS, Shah AP, Shah PA, Shrivastav PS, Athar M. New Class of Supramolecular Bowl-Shaped Columnar Mesogens Derived from Thiacalix[4]arene Exhibiting Gelation and Organic Light-Emitting Diodes Applications. ACS OMEGA 2019; 4:15862-15872. [PMID: 31592456 PMCID: PMC6776968 DOI: 10.1021/acsomega.9b01776] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2019] [Accepted: 09/09/2019] [Indexed: 06/10/2023]
Abstract
A new class of blue light-emitting bowl-shaped mesogens with the thiacalix[4]arene core appended with 1,3,4-thiadiazole derivatives having peripheral alkoxy side chains have been synthesized and well characterized. The liquid crystalline behavior of present synthesized derivatives was examined by optical polarizing microscopy, differential scanning calorimetry, and X-ray diffraction studies. It was observed that these thiacalix[4]arene derivatives were capable of stabilizing the observed Colh phase with a higher temperature range. The cone-shaped thiacalix[4]arene-based liquid crystals with peripheral alkoxy side chains able to pack into the columns with enriched intermolecular interactions and thermal behavior. All derivatives showed blue luminescence in solution, solid thin-film, and gelation state. The hexagonal columnar phase and emissive nature of thiadiazole-based thiacalixarene compounds having xerogel behavior make them favorable in the application of emissive electronic display devices. The electrochemical properties of these thiacalixarene-based compounds demonstrate the effect of alkyl side chain on the highest occupied molecular orbital-lowest unoccupied molecular orbital energy levels and also exhibited lower electron band gaps. The electroluminescence behavior of the compound 10c was examined as emissive layers in the fabrication of organic light-emitting diodes.
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Affiliation(s)
- Vinay S. Sharma
- Department
of Chemistry, Faculty of Basic and Applied Sciences, Madhav University, Abu
Road, Sirohi 307026, Rajasthan, India
| | - Anuj S. Sharma
- Department
of Chemistry, School of Science, Gujarat
University, Ahmedabad 380009, Gujarat, India
| | - Akshara P. Shah
- Department
of Chemistry, Mumbai University, Santacruz, Mumbai 400
098, India
| | - Priyanka A. Shah
- Department
of Chemistry, School of Science, Gujarat
University, Ahmedabad 380009, Gujarat, India
| | - Pranav S. Shrivastav
- Department
of Chemistry, School of Science, Gujarat
University, Ahmedabad 380009, Gujarat, India
| | - Mohd Athar
- Department
of Chemistry, Central University of Gujarat, Ghandhinagar 382030, India
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8
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De J, Yang WY, Bala I, Gupta SP, Yadav RAK, Dubey DK, Chowdhury A, Jou JH, Pal SK. Room-Temperature Columnar Liquid Crystals as Efficient Pure Deep-Blue Emitters in Organic Light-Emitting Diodes with an External Quantum Efficiency of 4.0. ACS APPLIED MATERIALS & INTERFACES 2019; 11:8291-8300. [PMID: 30707013 DOI: 10.1021/acsami.8b18749] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
A novel design of aggregation-induced emission (AIE) active columnar (Col) luminomesogens is reported, and they are demonstrated to act as highly efficient deep-blue emitters in organic light-emitting diodes (OLEDs). All derivatives exhibit Col liquid crystalline (LC) behavior at room temperature over a wide temperature range and desirable alignment properties, which is very important in using them as materials for organic electronic devices. These new AIE active luminomesogens were found to act as highly efficient emitters in OLEDs and unveiled a maximum external quantum efficiency of 4.0% for the first time in Col LCs with Commission International de l'E'clairage coordinates of (0.17, 0.07), which closely matches the National Television System Committee (NTSC) standard, corresponding to pure deep blue color. The detailed supramolecular assembly of the compounds has been characterized by modeling in the mesophase derived from small- and wide-angle X-ray scattering results.
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Affiliation(s)
- Joydip De
- Department of Chemical Sciences , Indian Institute of Science Education and Research (IISER) Mohali , Sector-81, SAS Nagar, Knowledge City , Manauli 140306 , India
| | - Wan-Yun Yang
- Department of Materials Science and Engineering , National Tsing Hua University , Hsinchu 30013 , Taiwan
| | - Indu Bala
- Department of Chemical Sciences , Indian Institute of Science Education and Research (IISER) Mohali , Sector-81, SAS Nagar, Knowledge City , Manauli 140306 , India
| | | | - Rohit Ashok Kumar Yadav
- Department of Materials Science and Engineering , National Tsing Hua University , Hsinchu 30013 , Taiwan
| | - Deepak Kumar Dubey
- Department of Materials Science and Engineering , National Tsing Hua University , Hsinchu 30013 , Taiwan
| | - Arjun Chowdhury
- Department of Chemical Sciences , Indian Institute of Science Education and Research (IISER) Mohali , Sector-81, SAS Nagar, Knowledge City , Manauli 140306 , India
| | - Jwo-Huei Jou
- Department of Materials Science and Engineering , National Tsing Hua University , Hsinchu 30013 , Taiwan
| | - Santanu Kumar Pal
- Department of Chemical Sciences , Indian Institute of Science Education and Research (IISER) Mohali , Sector-81, SAS Nagar, Knowledge City , Manauli 140306 , India
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Gupta RK, Sudhakar AA. Perylene-Based Liquid Crystals as Materials for Organic Electronics Applications. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:2455-2479. [PMID: 29929366 DOI: 10.1021/acs.langmuir.8b01081] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Columnar phases formed by the stacking of disclike molecules with an intimate π-π overlap forms a 1D pathway for the anisotropic charge migration along the columns. Columnar phases have great potential in organic electronic devices to be utilized as active semiconducting layers in comparison to organic single crystals or amorphous polymers in terms of processability, ease of handling, and high charge carrier mobility. Intelligent molecular engineering of perylene and its derivatives provided access to tune the physical properties and self-assembly behavior. The columnar phase formed by perylene derivatives has great potential in the fabrication of organic electronic devices. There are several positions on the perylene molecule, which can be functionalized to tune its self-assembly, as well as optoelectronic properties. Thus, many liquid-crystalline molecules stabilizing the columnar phase, which are based on perylene tetraesters, perylene diester imides, and perylene bisimides, have been synthesized over the years. Their longitudinal and laterally extended derivatives, bay-substituted derivatives exhibiting a columnar phase, are reported. In addition, several liquid-crystalline oligomers and polymers based on perylene derivatives were also reported. All such modifications provide an option to tune the energy levels of frontier molecular orbitals with respect to the work function of the electrodes in devices and also the processability of such materials. In this feature article, we attempt to provide an overview of the molecular design developed to tune the applicable properties and self-assembly of perylene derivatives as well as recent developments related to their application in the fabrication of organic solar cells, organic light-emitting diodes, and organic field-effect transistors.
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Affiliation(s)
- Ravindra Kumar Gupta
- Department of Chemistry , Indian Institute of Technology Guwahati , Guwahati 781039 , Assam , India
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10
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Devi S, Bala I, Gupta SP, Kumar P, Pal SK, Venkataramani S. Reversibly photoswitchable alkoxy azobenzenes connected benzenetricarboxamide discotic liquid crystals with perpetual long range columnar assembly. Org Biomol Chem 2019; 17:1947-1954. [DOI: 10.1039/c8ob01579a] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Reversibly photoswitchable discotic liquid crystals (DLCs) with no change in columnar assembly.
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Affiliation(s)
- Sudha Devi
- Department of Chemical Sciences
- Indian Institute of Science Education and Research (IISER)
- Manauli-140306
- India
| | - Indu Bala
- Department of Chemical Sciences
- Indian Institute of Science Education and Research (IISER)
- Manauli-140306
- India
| | | | - Pravesh Kumar
- Department of Chemical Sciences
- Indian Institute of Science Education and Research (IISER)
- Manauli-140306
- India
| | - Santanu Kumar Pal
- Department of Chemical Sciences
- Indian Institute of Science Education and Research (IISER)
- Manauli-140306
- India
| | - Sugumar Venkataramani
- Department of Chemical Sciences
- Indian Institute of Science Education and Research (IISER)
- Manauli-140306
- India
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11
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Sharma VS, Shah AP, Sharma AS, Athar M. Columnar self-assembly, gelation and electrochemical behavior of cone-shaped luminescent supramolecular calix[4]arene LCs based on oxadiazole and thiadiazole derivatives. NEW J CHEM 2019. [DOI: 10.1039/c8nj04922j] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
A new class of blue light-emitting supramolecular liquid crystalline cone or bowl-shaped compounds were synthesized from substituted 1,3,4-oxadiazoles and 1,3,4-thiadiazoles with calix[4]arene derivatives.
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Affiliation(s)
- Vinay S. Sharma
- Department of Chemistry
- Faculty of Basic and Applied Science
- Madhav University
- Sirohi
- India
| | | | - Anuj S. Sharma
- Department of Chemistry
- School of Science
- Gujarat University
- Ahmedabad
- India
| | - Mohd Athar
- CCG@CUG
- School of Chemical Sciences
- Central University of Gujarat
- Ghandhinagar
- India
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12
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Sharma VS, Singh HK, Sharma AS, Shah AP, Shah PA. Bowl-shaped fluorescent liquid crystals derived from 4-tert butyl calix[4]arene and trans cinnamic acid derivatives. NEW J CHEM 2019. [DOI: 10.1039/c9nj03097b] [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
A new family of bowl-shaped molecules with a calix[4]arene rigid core appended by four-side and two-side substitution with trans 4-n-alkoxy cinnamic acid has been synthesized and well characterized.
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Affiliation(s)
- Vinay S. Sharma
- Department of Chemistry
- Faculty of Basic and Applied Science
- Madhav University
- Sirohi
- India
| | - Hemant Kumar Singh
- Department of Chemistry
- Indian Institute of Technology Guwahati
- Guwahati-781039
- India
| | - Anuj S. Sharma
- Department of Chemistry, School of Science, Gujarat University
- Ahmedabad
- India
| | | | - Priyanka A. Shah
- Department of Chemistry, School of Science, Gujarat University
- Ahmedabad
- India
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13
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Bala I, Gupta SP, Kumar S, Singh H, De J, Sharma N, Kailasam K, Pal SK. Hydrogen-bond mediated columnar liquid crystalline assemblies of C 3-symmetric heptazine derivatives at ambient temperature. SOFT MATTER 2018; 14:6342-6352. [PMID: 30027180 DOI: 10.1039/c8sm00834e] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
A new class of hydrogen (H) bonded fluorescent liquid crystals (FLCs) based on a newly discovered s-heptazine fluorophore discotic component have been synthesized. The tendency of the s-heptazine core to form H-bonded LCs has been explored for the first time. Interestingly, the pure heptazine derivatives (non-mesomorphic) on complexation with tri-alkoxy benzoic acids exhibit enantiotropic columnar mesomorphism over a wide range of temperatures including room temperature. This indicates the strength of the resulting H-bonded complexes. The H-bonded supramolecular complexes were studied through FT-IR, temperature dependent FT-IR and NMR studies and H-D exchange studies, and their thermal behaviour was deduced through polarized optical microscopy (POM), differential scanning calorimetry (DSC) and X-ray diffraction (XRD) studies. Because of the inherently fluorescent pure heptazine derivative, the resulting complexes exhibit fluorescent behaviour in the solution state as well as in the solid state.
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Affiliation(s)
- Indu Bala
- Indian Institute of Science Education and Research (IISER) Mohali, Sector-81, SAS Nagar, Mohali 140306, India.
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Bhattacharjee S, Lugger JAM, Sijbesma RP. Pore size dependent cation adsorption in a nanoporous polymer film derived from a plastic columnar phase. Chem Commun (Camb) 2018; 54:9521-9524. [DOI: 10.1039/c8cc03292k] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Nanoporous polymer films were fabricated from a plastic columnar phase that showed pore size and shape (whether open or collapsed) dependent cation adsorption properties.
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Affiliation(s)
- Subham Bhattacharjee
- Laboratory of Molecular Science and Technology
- Eindhoven University of Technology
- Eindhoven
- The Netherlands
- Institute for Complex Molecular Systems
| | - Jody A. M. Lugger
- Laboratory of Molecular Science and Technology
- Eindhoven University of Technology
- Eindhoven
- The Netherlands
- Institute for Complex Molecular Systems
| | - Rint P. Sijbesma
- Laboratory of Molecular Science and Technology
- Eindhoven University of Technology
- Eindhoven
- The Netherlands
- Institute for Complex Molecular Systems
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Zhu M, Chen Y, Guo H, Yang F, Song X. Perylene liquid crystals with multiple alkyl chains: investigation of the influence of peripheral alkyl chain number on mesomorphic and photophysical properties. NEW J CHEM 2018. [DOI: 10.1039/c8nj00480c] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Novel perylene liquid crystals with 2, 4 and 6 peripheral alkyl chains or 6, 8 and 10 peripheral alkyl chains at both the imide and bay-positions were investigated.
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Affiliation(s)
- Mingguang Zhu
- College of Chemistry and Materials Science
- Fujian Normal University
- Fuzhou 350007
- P. R. China
| | - Yongzhu Chen
- College of Chemistry and Materials Science
- Fujian Normal University
- Fuzhou 350007
- P. R. China
| | - Hongyu Guo
- College of Chemistry and Materials Science
- Fujian Normal University
- Fuzhou 350007
- P. R. China
| | - Fafu Yang
- College of Chemistry and Materials Science
- Fujian Normal University
- Fuzhou 350007
- P. R. China
- Fujian Key Laboratory of Polymer Materials
| | - Xuchun Song
- College of Chemistry and Materials Science
- Fujian Normal University
- Fuzhou 350007
- P. R. China
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16
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De J, Gupta SP, Bala I, Kumar S, Pal SK. Phase Behavior of a New Class of Anthraquinone-Based Discotic Liquid Crystals. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:13849-13860. [PMID: 29117677 DOI: 10.1021/acs.langmuir.7b03031] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Five novel columnar liquid crystalline compounds (4.1-4.5) consisting of a central anthraquinone core carrying four alkoxy chains (R = n-C6H13, n-C8H17, n-C10H21, n-C12H25, and 3,7-dimethyl octyl) with two diagonally opposite 1-ethynyl-4-pentylbenzene units were synthesized, and their phase transitions were investigated between changes in the molecular structure and their self-assembly into the columnar mesophases. Small and wide-angle X-ray scattering (SAXS/WAXS) studies were performed to deduce the exact nature of the mesophases, and their corresponding electron density maps were derived from the intensities of the peaks observed in the diffraction patterns. A comparison of compounds with different alkoxy chains indicated that the soft crystal columnar rectangular (Crcolrec) phase was stable at lower temperature for the shortest peripheral alkoxy chain (4.1; R = n-C6H13) and was found to exhibit the columnar hexagonal (Colh) phase and then the discotic nematic (ND) phase with increasing temperature. In contrast, increasing the peripheral chain length to n-C8H17 or the branched one (4.2 and 4.5) stabilized the Colh phase at lower temperature and showed the ND phase at higher temperature. Further increase in chain length (4.3 and 4.4; n-C10H21, n-C12H25) demonstrated the formation of the ND phase. Conductivity measurement in the Colh mesophase was found to be almost 10 times higher in magnitude than the corresponding Crcolrec phase. The HOMO-LUMO band gap of all the compounds was found to be in the range from 2.79 to 2.82 eV, which is quite less and comparable with the optical energy band gap.
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Affiliation(s)
- Joydip De
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Mohali , Sector-81, SAS Nagar, Knowledge City, Manauli 140306, India
| | - Santosh Prasad Gupta
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Mohali , Sector-81, SAS Nagar, Knowledge City, Manauli 140306, India
| | - Indu Bala
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Mohali , Sector-81, SAS Nagar, Knowledge City, Manauli 140306, India
| | - Sandeep Kumar
- Raman Research Institute , C. V. Raman Avenue, Bangalore 560 080, India
| | - Santanu Kumar Pal
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Mohali , Sector-81, SAS Nagar, Knowledge City, Manauli 140306, India
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Bader K, Neidhardt MM, Wöhrle T, Forschner R, Baro A, Giesselmann F, Laschat S. Amino acid/crown ether hybrid materials: how charge affects liquid crystalline self-assembly. SOFT MATTER 2017; 13:8379-8391. [PMID: 29063090 DOI: 10.1039/c7sm01484h] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
To probe the influence of electrostatic interactions on the mesomorphic self-assembly and phase behaviour of hybrid liquid crystals a series of crown ether/tyrosine hybrid systems was prepared by Steglich esterification of alkyl N-(tert-butoxycarbonyl)-l-tyrosinates with 4-carboxybenzo[15]crown-5 and 4-carboxybenzo[18]crown-6. The obtained derivatives allowed further manipulations at the NH functional group and complexation of the crown ether unit with NaI to give neutral or charged hybrid materials. All compounds were investigated by differential scanning calorimetry (DSC), polarizing optical microscopy (POM) and X-ray diffraction (XRD) measurements. Neither the variation of the N-protecting group, introduction of charge at the N-terminus nor anion exchange (Cl vs. I) resulted in mesomorphism. In contrast, N-Boc-protected and unprotected hybrids formed rectangular columnar (Colr) mesophases with phase widths up to 35 K. NaI complexation switched these neutral thermotropic derivatives into ionic liquid crystals (ILCs) and induced a change of mesophase type from Colr to smectic A (SmA). A comparison of experimentally obtained layer distances and theoretically calculated molecular lengths indicated bilayer SmA formation with interdigitated alkyl chains. Packing models for both mesophase types are proposed and discussed with respect to stabilizing interactions.
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Affiliation(s)
- Korinna Bader
- Institut für Organische Chemie, Universität Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany.
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