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Ohsato H, Kawauchi K, Yamada S, Konno T. Diverse Synthetic Transformations Using 4-Bromo-3,3,4,4-tetrafluorobut-1-ene and Its Applications in the Preparation of CF 2 CF 2 -Containing Sugars, Liquid Crystals, and Light-Emitting Materials. CHEM REC 2023; 23:e202300080. [PMID: 37140105 DOI: 10.1002/tcr.202300080] [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: 03/01/2023] [Revised: 04/16/2023] [Indexed: 05/05/2023]
Abstract
Organic molecules with fluoroalkylene scaffolds, especially a tetrafluoroethylene (CF2 CF2 ) moiety, in their molecular structures exhibit unique biological activities, or can be applied to functional materials such as liquid crystals and light-emitting materials. Although several methods for the syntheses of CF2 CF2 -containing organic molecules have been reported to date, they have been limited to methods using explosives and fluorinating agents. Therefore, there is an urgent need to develop simple and efficient approaches to synthesize CF2 CF2 -containing organic molecules from readily available fluorinated substrates using carbon-carbon bond formation reactions. This personal account summarizes the simple and efficient transformation of functional groups at both ends of 4-bromo-3,3,4,4-tetrafluorobut-1-ene and discusses its synthetic applications to biologically active fluorinated sugars and functional materials, such as liquid crystals and light-emitting molecules.
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Affiliation(s)
- Haruka Ohsato
- Faculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto, 606-8585, Japan
| | - Kazuma Kawauchi
- Faculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto, 606-8585, Japan
| | - Shigeyuki Yamada
- Faculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto, 606-8585, Japan
| | - Tsutomu Konno
- Faculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto, 606-8585, Japan
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Yamada S, Konno T. Development of Donor-π-Acceptor-Type Fluorinated Tolanes as Compact Condensed Phase Luminophores and Applications in Photoluminescent Liquid-Crystalline Molecules. CHEM REC 2023; 23:e202300094. [PMID: 37098883 DOI: 10.1002/tcr.202300094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 04/13/2023] [Indexed: 04/27/2023]
Abstract
Fluorinated tolanes, produced by introducing fluorine atoms into one of the aromatic rings of tolane, emitted almost no fluorescence in a solution state, but the fluorescence intensity increased dramatically in the crystalline state because of intermolecular H⋅⋅⋅F hydrogen bonds. The photoluminescent (PL) colors depend on the molecular orbitals, dipole moments, and molecular aggregated structures can be varied by controlling terminal substituents along the major molecular axis. The introduction of a long alkoxy or semifluoroalkoxy unit as a flexible chain into the terminal positions along the major molecular axis induced the formation of a liquid-crystalline (LC) phase; fluorinated tolanes act both as luminophores and as mesogens, leading to the molecular design of new photoluminescent LC molecules (PLLCs). The results also indicated that a fluorinated tolane dimer, which consists of two fluorinated tolanes linked by a flexible alkylene spacer, also becomes a novel PLLC.
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Affiliation(s)
- Shigeyuki Yamada
- Faculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto, 606-8585, Japan
| | - Tsutomu Konno
- Faculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto, 606-8585, Japan
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Development of photoluminescent liquid-crystalline dimers bearing two fluorinated tolane-based luminous mesogens. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.119884] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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Yamada S, Kobayashi K, Konno T. Development of Yellow-to-Orange Photoluminescence Molecules Based on Alterations in the Donor Units of Fluorinated Tolanes. Molecules 2022; 27:molecules27185782. [PMID: 36144519 PMCID: PMC9504459 DOI: 10.3390/molecules27185782] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 09/04/2022] [Accepted: 09/05/2022] [Indexed: 11/25/2022] Open
Abstract
Since the aggregation-induced emission (AIE) phenomenon was first reported by Tang et al., much effort has been devoted to the development of solid-state luminescent molecules by chemists worldwide. Our group successfully developed fluorinated tolanes as novel compact π-conjugated luminophores with blue photoluminescence (PL) in the crystalline state. Moreover, we reported the yellow-green PL molecules based on their electron-density distributions. In the present study, we designed and synthesized fluorinated tolanes with various amine-based donors and evaluated their photophysical properties. The carbazole-substituted fluorinated tolane exhibited strong PL in the solution state, whereas piperidine- or phenothiazine-substituted fluorinated tolanes showed a dramatic decrease in PL efficiency. Notably, fluorinated tolanes with piperidine or phenothiazine substituents displayed yellow-to-orange PL in the crystalline state; this may have occurred because these tolanes exhibited tightly packed structures formed by intermolecular interactions, such as H···F hydrogen bonds, which suppressed the non-radiative deactivation process. Moreover, fluorinated tolanes with amine-based donors exhibited AIE characteristics. We believe that these yellow-to-orange solid PL molecules can contribute to the development of new solid luminescent materials.
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Development of thermoresponsive near-ultraviolet photoluminescent liquid crystals using hexyloxy-terminated fluorinated tolane dimers connected with an alkylene spacer. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.119755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Yamada S, Kataoka M, Yoshida K, Nagata M, Agou T, Fukumoto H, Konno T. Photophysical and thermophysical behavior of D-π-A-type fluorinated diphenylacetylenes bearing an alkoxy and an ethoxycarbonyl group at both longitudinal molecular terminals. J Fluor Chem 2022. [DOI: 10.1016/j.jfluchem.2022.110032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Yamada S, Kobayashi K, Morita M, Konno T. D–π–A-type fluorinated tolanes with a diphenylamino group: crystal polymorphism formation and photophysical behavior. CrystEngComm 2022. [DOI: 10.1039/d1ce01671g] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Ph2N-Substituted fluorinated tolanes produced two polymorphisms, which display a distinct photoluminescence behavior; one polymorphism showed green PL and the other exhibited yellow PL.
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Affiliation(s)
- Shigeyuki Yamada
- Faculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Kazuki Kobayashi
- Faculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Masato Morita
- Faculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Tsutomu Konno
- Faculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
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Yamada S, Sato M, Uto E, Kataoka M, Morita M, Konno T. Fluorinated tolane-based fluorophores bearing a branched flexible unit with aggregation-induced emission enhancement characteristics. NEW J CHEM 2022. [DOI: 10.1039/d1nj05822c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Precise molecular design of fluorinated tolane-based fluorophores can control both the electron density and molecular aggregated structures.
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Affiliation(s)
- Shigeyuki Yamada
- Faculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Masaya Sato
- Faculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Eiji Uto
- Faculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Mitsuki Kataoka
- Faculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Masato Morita
- Faculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Tsutomu Konno
- Faculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
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Morita M, Yamada S, Konno T. Halogen atom effect of fluorinated tolanes on their luminescence characteristics. NEW J CHEM 2022. [DOI: 10.1039/d1nj05539a] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Modification of the halogen constituent in the fluorinated tolane moiety is an effective method for tailoring the functionality of the material.
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Affiliation(s)
- Masato Morita
- Faculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Shigeyuki Yamada
- Faculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Tsutomu Konno
- Faculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
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Effect of Fluoroalkyl-Substituent in Bistolane-Based Photoluminescent Liquid Crystals on Their Physical Behavior. CRYSTALS 2021. [DOI: 10.3390/cryst11040450] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Photoluminescent liquid crystals (PLLCs) have attracted significant attention owing to their broad applicability in thermosensing and PL switching. Extensive efforts have been made to develop bistolane-based PLLCs containing flexible units at both molecular terminals, and it has been revealed that their PL behavior can switch with the phase transition between the crystalline and LC phases. Although slight modulation of the flexible unit structure dramatically alters the LC and PL behaviors, few studies into the modification of the flexible units have been conducted. With the aim of achieving dynamic changes in their physical behaviors, we developed a family of bistolane derivatives containing a simple alkyl or a fluoroalkyl flexible chain and carried out a detailed systematic evaluation of their physical behaviors. Bistolanes containing a simple alkyl chain showed a nematic LC phase, whereas switching the flexible chain in the bistolane to a fluoroalkyl moiety significantly altered the LC phase to generate a smectic phase. The fluoroalkyl-containing bistolanes displayed a stronger deep blue PL than their corresponding non-fluorinated counterparts, even in the crystalline phase, which was attributed to the construction of rigid molecular aggregates through intermolecular F···H and F···F interactions to suppress non-radiative deactivation.
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Systematic Studies on the Effect of Fluorine Atoms in Fluorinated Tolanes on Their Photophysical Properties. Molecules 2021; 26:molecules26082274. [PMID: 33919915 PMCID: PMC8070916 DOI: 10.3390/molecules26082274] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 04/06/2021] [Accepted: 04/08/2021] [Indexed: 11/29/2022] Open
Abstract
In this study, we synthesized a series of fluorinated and non-fluorinated tolanes, in which one or more fluorine atoms were systematically introduced into one aromatic ring of a tolane scaffold, and systematically evaluated their photophysical properties. All the tolanes with or without fluorine substituents were found to have poor photoluminescence (PL) in tetrahydrofuran (THF) solutions. On the other hand, in the crystalline state, non-fluorinated and fluorinated tolanes with one or four fluorine atoms were less emissive, whereas fluorinated tolanes with three or five fluorine atoms exhibited high PL efficiencies (ФPL) up to 0.51. X-ray crystallographic analyses of the emissive fluorinated tolanes revealed that the position of the fluorine substituent played a key role in achieving a high ФPL. Fluorine substituents at the ortho (2/6) and para (4) positions led to tight and rigid packing due to plural π–π stacking and/or hydrogen bonding interactions, resulting in enhanced ФPL caused by the suppression of non-radiative deactivation. Additionally, fluorinated tolanes with three fluorine atoms exhibited notable aggregation-induced PL emission enhancement in THF/water mixed solvents. This demonstrates that the PL characteristics of small PL materials can be tuned depending on the usage requirements.
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Fluorinated Tolane Dyads with Alkylene Linkage: Synthesis and Evaluation of Photophysical Characteristics. CRYSTALS 2020. [DOI: 10.3390/cryst10080711] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Light-emitting materials have received considerable attention because of their broad applications as substrates in bio-imaging and sensing components, light-emitting displays, and lighting devices. Herein, we developed fluorinated tolane and bistolane derivatives containing fluorinated aromatic rings and demonstrated their intense photoluminescence (PL) characteristics in crystalline powder states. We focused on molecules showing varied PL behavior with a change in the molecular aggregated structures. We synthesized novel fluorinated tolane dyads consisting of fluorinated tolane-based π-conjugated scaffolds and flexible alkylene linkages to control both the electron-density distribution and molecular aggregated states. Fluorinated tolane dyads connected with an alkylene linkage showed blue PL in a dilute solution, but the PL efficiency achieved was low. In contrast, the crystalline powder of tolane dyad substrates exhibited dual emission—relatively intense blue to deep blue PL—originating from monomer and aggregate emission. The PL behavior changed significantly with the alkylene linkage and the application of a mechanical stimulus to the crystalline powder sample. The fluorinated tolane dyads developed in this study could serve as stimulus-responsive photoluminescent materials suitable for optical applications.
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