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Imine-based highly polar achiral unsymmetrical four-ring bent shaped liquid crystals: Design, Synthesis and Characterization. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2022.133496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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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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Punjani V, Mohiuddin G, Kaur S, Choudhury AR, Paladugu S, Dhara S, Ghosh S, Pal SK. Chiral Bent-Shaped Molecules Exhibiting Unusually Wide Range of Blue Liquid-Crystalline Phases and Multistimuli-Responsive Behavior. Chemistry 2020; 26:5859-5871. [PMID: 32083772 DOI: 10.1002/chem.201905707] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 02/02/2020] [Indexed: 11/11/2022]
Abstract
Recently, an unprecedented observation of polar order, thermochromic behavior, and exotic mesophases in new chiral, bent-shaped systems with a -CH3 moiety placed at the transverse position of the central core was reported. Herein, a homologous series of compounds with even-numbered carbon chains from n=4 to 18 were synthesized, in which -Cl was substituted for -CH3 at the kink position and a drastic modification in the phase structure of the bent-shaped molecule was observed. An unusual stabilization of the cubic blue phase (BP) over a wide range of 16.4 °C has been witnessed. Two homologues in this series (1-12 and 1-14) exhibit an interesting phase sequence consisting of BPI/II, chiral nematic, twist grain boundary, smectic A, and smectic X (SmX) phases. The higher homologues (1-16 and 1-18) stabilize the SmX phase enantiotropically over the entire temperature range. Crystal structure analysis confirmed the bent molecular architecture, with a bent angle of 148°, and revealed the presence of two different molecular conformations in an asymmetric unit of compound 1-4. A DFT study corroborated that the -Cl moiety at the central core of the molecule led to an increase in the dipole moment along the transverse direction, which, in turn, facilitated the unusual stabilization of frustrated structures. Crystal polymorphism has been evidenced in three homologues (1-10, 1-12, and 1-14) of the series. On the application of mechanical pressure through grinding, compound 1-10 transformed from a bright yellow crystalline solid to a dark orange-green amorphous solid, which reversed upon dropwise addition of dichloromethane, indicating reversible mechanochromism in this class of compounds. In addition, excellent thermochromic behavior has been observed for compound 1-10 with a controlled temperature-color combination.
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Affiliation(s)
- Vidhika Punjani
- 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
| | - Supreet Kaur
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, Knowledge City, Manauli, 140306, India
| | - Angshuman Roy Choudhury
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, Knowledge City, Manauli, 140306, India
| | | | - Surajit Dhara
- School of Physics, University of Hyderabad, Hyderabad, 500046, India
| | - Sharmistha Ghosh
- Department of Physics, University of Calcutta, 92 Acharyya Prafulla Chandra Road, Kolkata, 700009, 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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Jain V, Mohiuddin G, Pal SK. Design, synthesis and application of 2-chloro-3-nitrobenzoic acid based three-ring bent-core molecules with a terminal halogen moiety. J Mol Struct 2020. [DOI: 10.1016/j.molstruc.2019.127383] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Gorokhov VY, Bykov YV, Batuev SA, Lystsova EA, Gorokhova SM, Yaganova NN. Single-Pot Synthesis Method of 2-Hydroxybenzylidene-4-[(aza, thio)xanthenyl]anilines and Their Plant Growth Regulator Activity. RUSS J GEN CHEM+ 2019. [DOI: 10.1134/s1070363219040042] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Gude V, Rout D, Panigrahi MK, Biradha K. Origin of green photoluminescence in four-ring bent-core molecules with ESIPT, selective sensing of zinc ions by turn-on emission and their liquid crystal properties. Photochem Photobiol Sci 2018; 17:1386-1395. [DOI: 10.1039/c8pp00216a] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Fluorescent four-ring symmetrical/unsymmetrical molecules containing alkyl chains of a varied number of –CH2– groups with a bent-core have been synthesized to explore their liquid crystalline (LC) and photophysical properties.
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Affiliation(s)
- Venkatesh Gude
- Department of Chemistry
- Indian Institute of Technology
- Kharagpur
- India
| | - Duttanjali Rout
- Department of Geology and Geophysics
- Indian Institute of Technology
- Kharagpur
- India
| | | | - Kumar Biradha
- Department of Chemistry
- Indian Institute of Technology
- Kharagpur
- India
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Ghule NV, Bhosale RS, Bhosale SV, Srikanth T, Rao NVS, Bhosale SV. Synthesis and Liquid Crystalline Properties of Unsymmetrically Substituted Naphthalenediimides with a Polar Headgroup: Effect of Amide Hydrogen Bonding and Alkyl Chain Length. ChemistryOpen 2018; 7:61-67. [PMID: 29318098 PMCID: PMC5754548 DOI: 10.1002/open.201700151] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Indexed: 11/18/2022] Open
Abstract
A series of new unsymmetrically substituted naphthalenediimide (NDI) moieties NDI-1 to NDI-6 were synthesized. The structures of these compounds were confirmed by means of FT-IR, 1H NMR, 13C NMR, ESI-mass and HRMS spectroscopic measurements. UV/Vis and fluorescence spectroscopy were employed to investigate the photophysical properties of the prepared compounds in solution and in the solid state. Using the onset of UV/Vis absorption, the optical band gaps were calculated. Cyclic voltammetry measurements were performed to study the electrochemical behavior and to calculate the LUMO energy levels. The thermal properties of NDI derivatives were studied by differential scanning calorimetry. The mesomorphic birefringent behavior of the NDI derivatives was investigated with polarizing optical microscopy. Among all of the studied NDI derivatives, only NDI-1, NDI-2, and NDI-3 showed liquid crystalline texture, owing to the presence of an amide linkage for H-bonding along with aromatic moieties for π-π-stacking.
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Affiliation(s)
- Namdev V. Ghule
- Polymers and Functional Materials DivisionCSIR-Indian Institute of Chemical TechnologyHyderabad500007, TelanganaIndia
| | - Rajesh S. Bhosale
- Polymers and Functional Materials DivisionCSIR-Indian Institute of Chemical TechnologyHyderabad500007, TelanganaIndia
| | - Sidhanath V. Bhosale
- Polymers and Functional Materials DivisionCSIR-Indian Institute of Chemical TechnologyHyderabad500007, TelanganaIndia
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Paul MK, Kalita G, Laskar AR, Debnath S, Gude V, Sarkar DD, Mohiuddin G, Varshney SK, Nandiraju Rao V. Synthesis and mesomorphic behaviour of achiral four-ring unsymmetrical bent-core liquid crystals: Nematic phases. J Mol Struct 2013. [DOI: 10.1016/j.molstruc.2013.06.044] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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