1
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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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2
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3
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Liu JB. The crystal structure of 1-fluoro-4-( p-tolylethynyl)benzene, C 15H 11F. Z KRIST-NEW CRYST ST 2021. [DOI: 10.1515/ncrs-2021-0190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
C15H11F, monoclinic, P21/n (no. 14), a = 6.2490(3) Å, b = 7.6343(4) Å, c = 24.2376(9) Å, β = 90.914(4)°, V = 1156.15(9) Å3, Z = 4, R
gt
(F) = 0.0619, wR
ref(F
2) = 0.1829, T = 293(2) K.
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Affiliation(s)
- Jin-Bao Liu
- Department of Pharmacy , Luohe Medical College , Luohe , 453003 , Henan , P. R. China
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4
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Kanakala MB, Yelamaggad CV. Exceptional dual fluorescent, excited-state intramolecular proton-transfer (ESIPT) columnar liquid crystals characterized by J-stacking and large Stokes shifts. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.115879] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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5
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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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6
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Kondo M, Morita Y, Nishida JI, Kawase T, Kawatsuki N. Mechano-induced photoluminescence colour change in an alkyltolane-terminated cyanostilbene. CrystEngComm 2021. [DOI: 10.1039/d1ce00456e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
A novel alkyltolane-terminated cyanostilbene is synthesized. The photoluminescence colour changed depending on the precipitation method, with either a red shift or blue shift in the photoluminescence spectra observed upon mechanical grinding.
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Affiliation(s)
- Mizuho Kondo
- Department of Applied Chemistry, Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji 671-2280, Japan
| | - Yuya Morita
- Department of Applied Chemistry, Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji 671-2280, Japan
| | - Jun-ichi Nishida
- Department of Applied Chemistry, Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji 671-2280, Japan
| | - Takeshi Kawase
- Department of Applied Chemistry, Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji 671-2280, Japan
| | - Nobuhiro Kawatsuki
- Department of Applied Chemistry, Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji 671-2280, Japan
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7
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Zhang W, Suzuki S, Sakurai T, Yoshida H, Tsutsui Y, Ozaki M, Seki S. Extended conjugation of ESIPT-type dopants in nematic liquid crystalline phase for enhancing fluorescence efficiency and anisotropy. Phys Chem Chem Phys 2020; 22:28393-28400. [PMID: 33305298 DOI: 10.1039/d0cp05415a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Organic compounds capable of excited-state intramolecular proton transfer (ESIPT) show fluorescence with a large Stokes shift and serve as solid-state emitters, luminescent dopants, and fluorescence-based sensing materials. Fluorescence of ESIPT molecules is usually increased in the solid state, but is weak in solvents due to the accelerated non-radiative decays by rotational motions of a part of the molecular core in these environments. Here we report, using a representative ESIPT motif 2-(2-hydroxyphenyl)benzothiazole (HBT), the extended-conjugation strategy of keeping sufficient fluorescence efficiency both in the solid state and in organic media. The introduction of an alkyl-terminated phenylene-ethynylene group into the HBT molecule dramatically enhances the fluorescence quantum yield from 0.01 to 0.20 in toluene and from 0.07 to 0.32 in a representative room-temperature nematic liquid crystal, 4-pentyl-4'-cyano biphenyl (5CB). The newly-synthesized CnP-C[triple bond, length as m-dash]C-HBT (n = 5 or 8) serves as a fluorescent dopant in 5CB and exhibits anisotropic fluorescence with the order parameter of 0.48, where the luminescence is controlled by the applied electric-field. The enhanced emission efficiency is rationalized by the larger height of energy barrier for the ESIPT process due to the introduction of phenylene-ethynylene groups.
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Affiliation(s)
- Wanying Zhang
- Department of Molecular Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan.
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8
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Yamada S, Higashida T, Wang Y, Morita M, Hosokai T, Maduwantha K, Koswattage KR, Konno T. Development of fluorinated benzils and bisbenzils as room-temperature phosphorescent molecules. Beilstein J Org Chem 2020; 16:1154-1162. [PMID: 32550930 PMCID: PMC7277987 DOI: 10.3762/bjoc.16.102] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Accepted: 05/20/2020] [Indexed: 12/24/2022] Open
Abstract
Pure organic phosphorescent molecules are attractive alternatives to transition-metal-complex-based phosphores for biomedical and technological applications owing to their abundance and nontoxicity. This article discloses the design, synthesis, and photophysical properties of fluorinated benzil and bisbenzil derivatives as potential pure organic room-temperature phosphorescent molecules. These compounds were separately converted from the corresponding fluorinated bistolanes via PdCl2-catalyzed oxidation by dimethyl sulfoxide, while nonfluorinated bistolane provided the corresponding bisbenzil derivatives exclusively in a similar manner. Intensive investigations of the photophysical properties of the benzil and bisbenzil derivatives in toluene at 25 °C showed both fluorescence with a photoluminescence (PL) band at a maximum wavelength (λPL) of around 400 nm and phosphorescence with a PL band at a λPL of around 560 nm. Interestingly, intersystem crossing effectively caused fluorinated benzils to emit phosphorescence, which may arise from immediate spin-orbit coupling involving the 1(n, π)→3(π, π) transition, unlike the case of fluorinated or nonfluorinated bisbenzil analogues. These findings offer a useful guide for developing novel pure organic room-temperature phosphorescent materials.
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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
| | - Takuya Higashida
- Faculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Yizhou Wang
- 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
| | - Takuya Hosokai
- National Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology, 1-1-1 Umezono, Tsukuba 305-8560, Japan
| | - Kaveendra Maduwantha
- National Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology, 1-1-1 Umezono, Tsukuba 305-8560, Japan.,Faculty of Technology, Sabaragamuwa University of Sri Lanka, P.O. Box 02, Belihuloya 70140, Sri Lanka
| | - Kaveenga Rasika Koswattage
- National Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology, 1-1-1 Umezono, Tsukuba 305-8560, Japan.,Faculty of Technology, Sabaragamuwa University of Sri Lanka, P.O. Box 02, Belihuloya 70140, Sri Lanka
| | - Tsutomu Konno
- Faculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
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9
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Yamada S, Nishizawa A, Agou T, Kubota T, Konno T. 1,2-Disubstituted 3,3,4,4,5,5-Hexafluorocyclopentenes as Bent Light-Emitting π-Conjugated Luminophores. European J Org Chem 2020. [DOI: 10.1002/ejoc.201901794] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Shigeyuki Yamada
- Faculty of Molecular Chemistry and Engineering; Kyoto Institute of Technology; Matsugasaki, Sakyo-ku 606-8585 Kyoto Japan
| | - Akito Nishizawa
- Faculty of Molecular Chemistry and Engineering; Kyoto Institute of Technology; Matsugasaki, Sakyo-ku 606-8585 Kyoto Japan
| | - Tomohiro Agou
- Department of Quantum Beam Science; Graduate School of Science and Engineering; Ibaraki University; 4-12-1 Naka-narusawa, Hitachi 316-8511 Ibaraki Japan
| | - Toshio Kubota
- Department of Quantum Beam Science; Graduate School of Science and Engineering; Ibaraki University; 4-12-1 Naka-narusawa, Hitachi 316-8511 Ibaraki Japan
| | - Tsutomu Konno
- Faculty of Molecular Chemistry and Engineering; Kyoto Institute of Technology; Matsugasaki, Sakyo-ku 606-8585 Kyoto Japan
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10
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Morita M, Yamada S, Konno T. Fluorine-induced emission enhancement of tolanes via formation of tight molecular aggregates. NEW J CHEM 2020. [DOI: 10.1039/d0nj01268h] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Incorporation of fluorine atoms into the tolane backbone constructed tight crystal packing structures to suppress molecular motions, which provided dramatic enhancement of photoluminescence efficiency in crystalline state.
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Affiliation(s)
- Masato Morita
- Faculty of Molecular Chemistry and Engineering
- Kyoto Institute of Technology
- Matsugasaki
- Kyoto 606-8585
- Japan
| | - Shigeyuki Yamada
- Faculty of Molecular Chemistry and Engineering
- Kyoto Institute of Technology
- Matsugasaki
- Kyoto 606-8585
- Japan
| | - Tsutomu Konno
- Faculty of Molecular Chemistry and Engineering
- Kyoto Institute of Technology
- Matsugasaki
- Kyoto 606-8585
- Japan
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11
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Yamada S, Mitsuda A, Adachi K, Hara M, Konno T. Development of light-emitting liquid-crystalline polymers with a pentafluorinated bistolane-based luminophore. NEW J CHEM 2020. [DOI: 10.1039/d0nj00659a] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Light-emitting liquid-crystalline polymers showing PL in the pristine solid state can control their PL color from blue to light-blue via a thermal phase transition to LC phases, which originates from a dynamic change of aggregated structures.
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Affiliation(s)
- Shigeyuki Yamada
- Faculty of Molecular Chemistry and Engineering
- Kyoto Institute of Technology
- Kyoto 606-8585
- Japan
| | - Akira Mitsuda
- Faculty of Molecular Chemistry and Engineering
- Kyoto Institute of Technology
- Kyoto 606-8585
- Japan
| | - Kaoru Adachi
- Faculty of Molecular Chemistry and Engineering
- Kyoto Institute of Technology
- Kyoto 606-8585
- Japan
| | - Mitsuo Hara
- Graduate School of Engineering
- Nagoya University
- Nagoya 464-8603
- Japan
| | - Tsutomu Konno
- Faculty of Molecular Chemistry and Engineering
- Kyoto Institute of Technology
- Kyoto 606-8585
- Japan
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12
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Veerabhadraswamy BN, Bhat SA, Hiremath US, Yelamaggad CV. Light-Emitting Chiral Nematic Dimers with Anomalous Odd-Even Effect. Chemphyschem 2019; 20:2836-2851. [PMID: 31517434 DOI: 10.1002/cphc.201900716] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 09/12/2019] [Indexed: 11/06/2022]
Abstract
In this report, based on the results derived from the extensive study into the thermal and photophysical properties, an anomalous mesomorphic behavior of photoluminescent, chiral nematic (N*) liquid crystalline dimers, belonging to two different series has been revealed. They comprise cholesterol and fluorescent three-ring Schiff base or salicylaldimine core interlinked via an ω-oxyalkanoyloxy spacer of varying length and parity. The effect of molecular structure on the liquid crystal (LC) behavior and photophysical properties of both the series has been probed by varying the length of the terminal n-alkoxy tails for a fixed (odd or even) parity of the spacer. The detailed investigations using complementary techniques not only evidenced the existence of the N* phase in all the dimers synthesized but also the occurrence of an intriguing odd-even effect; blue phases (BPs) exist in all the dimers comprising even-membered spacer, which surprisingly remains totally absent in their odd-membered counterparts. While the results reported hitherto are exactly opposite to the aforesaid findings, this atypical behavior has been interpreted in terms of the over-all shape of the dimers rendered by the orientation of terminal tails. Photophysical studies carried out clearly revealed the intrinsic light emitting feature of the dimers not only in their dilute solutions but also in their three condensed states viz., solid, N* phase, and isotropic liquid state; the emission intensities of the N* phase varies with the change in temperature, as expected. CD spectra of the N* phase recorded as a function of temperature show bisignate CD band characteristically, signifying large chiral correlations in the molecular self-assembly, while the origin of bands from positive to negative region suggests a right-handed twist of the N* helix.
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Affiliation(s)
- B N Veerabhadraswamy
- Centre for Nano and Soft Matter Sciences, P. B. No. 1329, Prof. U. R. Rao Road, Jalahalli, Bengaluru, 560 013, INDIA
| | - Sachin A Bhat
- Centre for Nano and Soft Matter Sciences, P. B. No. 1329, Prof. U. R. Rao Road, Jalahalli, Bengaluru, 560 013, INDIA
| | - Uma S Hiremath
- Centre for Nano and Soft Matter Sciences, P. B. No. 1329, Prof. U. R. Rao Road, Jalahalli, Bengaluru, 560 013, INDIA
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13
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Mrinalini M, Prasanthkumar S. Recent Advances on Stimuli‐Responsive Smart Materials and their Applications. Chempluschem 2019; 84:1103-1121. [DOI: 10.1002/cplu.201900365] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 07/25/2019] [Indexed: 12/25/2022]
Affiliation(s)
- Madoori Mrinalini
- Polymers & Functional Materials DivisionCSIR-Indian Institute of Chemical Technology (IICT) Tarnaka Hyderabad- 500007, Telangana India
- Academy of Scientific and Innovation Research (AcSIR) Kamla Nehru Nagar, Ghaziabad Uttar Pradesh 201002 India
| | - Seelam Prasanthkumar
- Polymers & Functional Materials DivisionCSIR-Indian Institute of Chemical Technology (IICT) Tarnaka Hyderabad- 500007, Telangana India
- Academy of Scientific and Innovation Research (AcSIR) Kamla Nehru Nagar, Ghaziabad Uttar Pradesh 201002 India
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14
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Yamada S, Nishizawa A, Morita M, Hosokai T, Okabayashi Y, Agou T, Hosoya T, Kubota T, Konno T. Synthesis and characterization of bent fluorine-containing donor-π-acceptor molecules as intense luminophores with large Stokes shifts. Org Biomol Chem 2019; 17:6911-6919. [PMID: 31271184 DOI: 10.1039/c9ob01300h] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Herein, we prepared novel bent fluorine-containing donor-π-acceptor (D-π-A) molecules from commercially available octafluorocyclopentene using a facile two-step procedure, revealing that the above molecules absorb UV-light and exhibit yellow photoluminescence (PL) with high PL efficiencies (ΦPL) in solution. The corresponding Stokes shifts exceeded 10 000 cm-1, and the maximum PL wavelength (λPL) strongly depended on solvent polarity or intermolecular interactions in the solid state. On the basis of a Lippert-Mataga plot, PL was confidently assigned to radiative relaxation from an intramolecular charge-transfer excited state. Moreover, the synthesized luminophores showed intense PL even in the crystalline state and exhibited alkoxy chain length-dependent PL behavior (e.g., high ΦPL, λPL = 486-540 nm).
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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.
| | - Akito Nishizawa
- 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.
| | - Takuya Hosokai
- National Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology, 1-1-1 Umezono, Tsukuba 305-8560, Japan
| | - Yusuke Okabayashi
- National Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology, 1-1-1 Umezono, Tsukuba 305-8560, Japan
| | - Tomohiro Agou
- Department of Quantum Beam Science, Graduate School of Science and Engineering, Ibaraki University, 4-12-1 Naka-narusawa, Hitachi, Ibaraki 316-8511, Japan
| | - Takaaki Hosoya
- Department of Quantum Beam Science, Graduate School of Science and Engineering, Ibaraki University, 4-12-1 Naka-narusawa, Hitachi, Ibaraki 316-8511, Japan
| | - Toshio Kubota
- Department of Quantum Beam Science, Graduate School of Science and Engineering, Ibaraki University, 4-12-1 Naka-narusawa, Hitachi, Ibaraki 316-8511, Japan
| | - Tsutomu Konno
- Faculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan.
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15
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Luminescence Tuning of Fluorinated Bistolanes via Electronic or Aggregated-Structure Control. APPLIED SCIENCES-BASEL 2019. [DOI: 10.3390/app9091905] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Organic luminescent materials have a wide range of practical applications, but the understanding of the relationship between molecular structure and luminescent behavior is lacking. Herein, we synthesized fluorinated bistolanes with an electron-donating alkoxy substituent at one terminal and an electron-withdrawing substituent at the other to realize systematic control of the electron-density distribution. Evaluation of the phase transition behavior revealed that most of the fluorinated bistolanes showed liquid-crystalline (LC) behavior, with the phase transition temperature depending on the terminal substituents. Additionally, the fluorinated luminophores displayed intense photoluminescence (PL) in solution and in their crystal phases. Remarkably, the PL color shifted dramatically depending on the dipole moment (μ||) along the long molecular axis; thus, PL tuning can be achieved through electronic modulation by precise control of the μ|| of the luminophore. Interestingly, in the LC phases under thermal conditions, the maximum PL band shifted by 0.210 eV upon phase transition from the crystal to smectic A LC phases, indicating that PL tuning can also be achieved by controlling the aggregated structure. These results offer a new molecular design for easily tunable PL materials using the molecular properties or external stimuli for promising applications, including light-emitting displays and PL sensing materials.
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16
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2-Chloroalkoxy-Substituted Pentafluorinated Bistolanes as Novel Light-Emitting Liquid Crystals. CRYSTALS 2019. [DOI: 10.3390/cryst9040195] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
In this study, we designed and synthesized novel pentafluorinated bistolane derivatives with 2-chloropentyl or 2-chlorohexyl flexible units as novel light-emitting liquid crystals (LELCs). By measuring the phase-transition behaviors, all derivatives were found to display liquid-crystalline (LC) phases during both heating and cooling processes. Among the novel bistolanes, the S- and R-configured derivatives exhibited a chiral nematic (N*) phase with a typical Grandjean optical texture. Interestingly, the chiral derivatives also exhibited a blue phase with a typical platelet texture in a narrow temperature range (2–4 °C). Photophysical measurements revealed that the 2-chloroalkoxy-substituted pentafluorinated bistolanes exhibited intense photoluminescence (PL) both in solution and in crystalline phases. The PL characteristics, especially the maximum PL wavelength, were found to switch sensitively during the heating and cooling cycles depending on the molecular aggregates through the crystal (Cr) ⇄ N* phase transition. The 2-chloroalkoxy flexible units induced dynamic changes in the LC and PL properties, providing valuable insight into the potential of various LELCs as PL sensing materials.
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17
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Yamada S, Tanaka T, Ichikawa T, Konno T. Novel V- and Y-Shaped Light-Emitting Liquid Crystals with Pentafluorinated Bistolane-Based Luminophores. ACS OMEGA 2019; 4:3922-3932. [PMID: 31459601 PMCID: PMC6649111 DOI: 10.1021/acsomega.8b03543] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 02/12/2019] [Indexed: 06/10/2023]
Abstract
Herein, we describe the synthesis of novel light-emitting liquid-crystalline (LC) compounds bearing pentafluorinated bistolane-based luminophores with a V- or a Y-shaped molecular geometry and the evaluation of their LC and photophysical characteristics. The V- or Y-shaped compounds exhibited a unique LC phase and showed photoluminescence (PL) behavior under various circumstances, such as in dilute solution or in the solid state. Notably, PL characteristics were observed even under high-temperature conditions with a crystal (Cr) to LC phase transition, although the PL efficiency (Φ PL) was gradually reduced because of thermal molecular motion. Interestingly, Φ PL was found to be completely recovered through the LC → Cr phase transition during the cooling process; the PL characteristics of the V- or Y-shaped compounds were sensitively changed by external thermal stress, giving these compounds the ability to act as thermoresponsive PL sensing materials.
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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
| | - Tsuyoshi Tanaka
- Faculty
of Molecular Chemistry and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Takahiro Ichikawa
- Department
of Biotechnology, Tokyo University of Agriculture
and Technology, Nakacho
2-24-16, Koganei, Tokyo 184-8588, Japan
| | - Tsutomu Konno
- Faculty
of Molecular Chemistry and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
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