Effect of fluoro-substituents on the phase behavior of donor-π-acceptor-type tolane-based liquid crystals containing decyleneoxy chain with imidazolium end groups
Yuto Eguchi; Masato Morita; Motohiro Yasui; Tsutomu Konno; Shigeyuki Yamada, Elsevier BV
Journal of Molecular Liquids, Mar. 2025, [Reviewed]

Solid-state red fluorescence of intramolecularly ring-fused donor–π–acceptor-type fluorinated diphenylacetylenes achieved by enhancing intramolecular charge transfer properties
Kazuki Kobayashi; Shigeyuki Yamada; Masato Morita; Tsuneaki Sakurai; Motohiro Yasui; Tsutomu Konno, Ring-fused donor–π–acceptor-type fluorinated diphenylacetylenes achieved red fluorescence redshift with maintained efficiency by precisely controlling intramolecular charge transfer properties and suppressing intramolecular rotation., Royal Society of Chemistry (RSC)
Journal of Materials Chemistry C, Jan. 2025, [Reviewed]

Access to optically active tetrafluoroethylenated amines based on [1,3]-proton shift reaction
Yuta Kabumoto; Eiichiro Yoshimoto; Bing Xiaohuan; Masato Morita; Motohiro Yasui; Shigeyuki Yamada; Tsutomu Konno, Treatment of various (R)-N-(2,2,3,3-tetrafluoropent-4-en-1-ylidene)-1-phenylethylamine derivatives with 2.4 equiv of DBU in toluene at room temperature to 50 °C for 24 h led to a smooth [1,3]-proton shift reaction with a high chirality transfer, affording the corresponding rearranged products in acceptable yields. Without purification, these products were subjected to acid hydrolysis and the subsequent N-Cbz protection, providing the optically active tetrafluoroethylenated amides in moderate three-step yields., Beilstein Institut
Beilstein Journal of Organic Chemistry, 01 Nov. 2024, [Reviewed]

Aggregation-induced enhanced fluorescence by hydrogen bonding in π-conjugated tricarbocycles with a CF₂CF₂-containing cyclohexa-1,3-diene skeleton
Haruka Ohsato; Masato Morita; Shigeyuki Yamada; Tomohiro Agou; Hiroki Fukumoto; Tsutomu Konno, A novel π-conjugated tricarbocycle with a CF₂CF₂-containing cyclohexa-1,3-diene skeleton was revealed to show aggregation-induced enhancement emission, which would pave the way for novel solid-state fluorescence materials., Royal Society of Chemistry (RSC)
Molecular Systems Design & Engineering, 09 Jun. 2022, [Reviewed]

Fluorinated tolane-based fluorophores bearing a branched flexible unit with aggregation-induced emission enhancement characteristics
Shigeyuki Yamada; Masaya Sato; Eiji Uto; Mitsuki Kataoka; Masato Morita; Tsutomu Konno, Precise molecular design of fluorinated tolane-based fluorophores can control both the electron density and molecular aggregated structures., Royal Society of Chemistry (RSC)
New Journal of Chemistry, 25 Jan. 2022, [Reviewed]

Halogen atom effect of fluorinated tolanes on their luminescence characteristics
Masato Morita; Shigeyuki Yamada; Tsutomu Konno, Lead, Modification of the halogen constituent in the fluorinated tolane moiety is an effective method for tailoring the functionality of the material., Royal Society of Chemistry (RSC)
New Journal of Chemistry, 20 Jan. 2022, [Reviewed]

D–π–A-type fluorinated tolanes with a diphenylamino group: crystal polymorphism formation and photophysical behavior
Shigeyuki Yamada; Kazuki Kobayashi; Masato Morita; Tsutomu Konno, Ph₂N-Substituted fluorinated tolanes produced two polymorphisms, which display a distinct photoluminescence behavior; one polymorphism showed green PL and the other exhibited yellow PL., Royal Society of Chemistry (RSC)
CrystEngComm, 17 Jan. 2022, [Reviewed]

Unsymmetrical Hexafluorocyclopentene-Linked Twisted π-Conjugated Molecules as Dual-State Emissive Luminophores
Shigeyuki Yamada; Akito Nishizawa; Kazuki Kobayashi; Keigo Yoshida; Masato Morita; Tomohiro Agou; Takaaki Hosoya; Hiroki Fukumoto; Tsutomu Konno, Dual-state emissive (DSE) luminophores, which can luminesce both in solution and in solid states, have recently attracted significant attention because of their broad applications. However, their development is difficult due to the difference in molecular design between solution- and solid-state luminophores. In this study, DSE luminophores based on unsymmetrical hexafluorocyclopentene-linked twisted π-conjugated structures carrying various substituents to tune the electron-density were designed and synthesized in a single-step reaction from heptafluorocyclopentene or perfluoro-1,2-diphenylcyclopentene derivatives. The twisted π-conjugated luminophores exhibited absorption in the UV region at approximately 330 nm, along with several signals in the high-energy region. Upon irradiating the luminophore solution (wavelength 330 nm), light-green to yellow photoluminescence (PL) was observed in the range of 422–471 nm with high PL efficiency. Theoretical calculations revealed that excitation from ground to excited states altered the structural shape of the luminophores from twisted to planar, leading to red-shifted PL and high PL efficiency (ΦPL). The intense blue PL exhibited by the luminophores in the crystalline state was attributed to their twisted molecular structures that suppressed non-radiative deactivation via the effective blocking of π/π stacking interactions., MDPI AG
Symmetry, 06 Oct. 2021, [Reviewed]

Effect of Fluoroalkyl-Substituent in Bistolane-Based Photoluminescent Liquid Crystals on Their Physical Behavior
Shigeyuki Yamada; Yizhou Wang; Masato Morita; Qingzhi Zhang; David O’Hagan; Masakazu Nagata; Tomohiro Agou; Hiroki Fukumoto; Toshio Kubota; Mitsuo Hara; Tsutomu Konno, 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., MDPI AG
Crystals, 20 Apr. 2021, [Reviewed]

Systematic Studies on the Effect of Fluorine Atoms in Fluorinated Tolanes on Their Photophysical Properties.
Masato Morita; Shigeyuki Yamada; Tsutomu Konno, Lead, 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.
Molecules (Basel, Switzerland), 14 Apr. 2021, [Reviewed]

Development of fluorinated benzils and bisbenzils as room-temperature phosphorescent molecules
Shigeyuki Yamada; Takuya Higashida; Yizhou Wang; Masato Morita; Takuya Hosokai; Kaveendra Maduwantha; Kaveenga Rasika Koswattage; Tsutomu Konno, 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 (λ_PL) of around 400 nm and phosphorescence with a PL band at a λ_PL 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., Beilstein Institut
Beilstein Journal of Organic Chemistry, 29 May 2020, [Reviewed]

Fluorine-induced emission enhancement of tolanes via formation of tight molecular aggregates
Masato Morita; Shigeyuki Yamada; Tsutomu Konno, Lead,

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.

, Royal Society of Chemistry (RSC)
New Journal of Chemistry, 08 Apr. 2020, [Reviewed]

Synthesis and characterization of bent fluorine-containing donor–π-acceptor molecules as intense luminophores with large Stokes shifts
Shigeyuki Yamada; Akito Nishizawa; Masato Morita; Takuya Hosokai; Yusuke Okabayashi; Tomohiro Agou; Takaaki Hosoya; Toshio Kubota; Tsutomu Konno,

Bent fluorine-containing D–π-A molecules showed intense photoluminescence with large Stokes shifts stem from their twisted and bent molecular geometries.

, Royal Society of Chemistry (RSC)
Organic & Biomolecular Chemistry, 02 Jul. 2019, [Reviewed]

Luminescence Tuning of Fluorinated Bistolanes via Electronic or Aggregated-Structure Control
Masato Morita; Shigeyuki Yamada; Tomohiro Agou; Toshio Kubota; Tsutomu Konno, Lead, 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., MDPI AG
Applied Sciences, 09 May 2019, [Reviewed]

Development of Novel Solid-State Light-Emitting Materials Based on Pentafluorinated Tolane Fluorophores
Shigeyuki Yamada; Akira Mitsuda; Kazuya Miyano; Tsuyoshi Tanaka; Masato Morita; Tomohiro Agou; Toshio Kubota; Tsutomu Konno, American Chemical Society (ACS)
ACS Omega, 14 Aug. 2018, [Reviewed]

Thermoresponsive luminescence properties of polyfluorinated bistolane-type light-emitting liquid crystals
Shigeyuki Yamada; Masato Morita; Tomohiro Agou; Toshio Kubota; Takahiro Ichikawa; Tsutomu Konno,

Thermoresponsive luminescent materials based on polyfluorinated bistolanes were developed and were found to show reversible PL switching by applying a thermal stimulus.

, Royal Society of Chemistry (RSC)
Organic & Biomolecular Chemistry, 13 Jul. 2018, [Reviewed]

Multi-color photoluminescence induced by electron-density distribution of fluorinated bistolane derivatives
Shigeyuki Yamada; Masato Morita; Tsutomu Konno, Elsevier BV
Journal of Fluorine Chemistry, 12 Sep. 2017, [Reviewed]

フルオロアルキル基を利用したベンゾチアゾール誘導体の発光波長制御　　　　　　　　　　　　　　　
吉野 陸; 福元 博基; 盛田 雅人
第47回 フッ素化学討論会, 14 Nov. 2024
20241114, 20241115

含フッ素ビフェニル型紫外発光分子の合成及び光学特性評価　　　　　　　　　　　　　　　
川崎 陽希; 福元 博基; 盛田 雅人
第47回 フッ素化学討論会, 14 Nov. 2024
20241114, 20241115

非共有結合性相互作用を活用した新規ビフェニル型発光分子の合成及びその物性評価　　　　　　　　　　　　　　　
川﨑 陽希; 盛田 雅人
第14回 CSJ化学フェスタ2024, 24 Oct. 2024
20241022, 20241024

嵩高い置換基を導入したベンゾチアゾール誘導体の光学特性　　　　　　　　　　　　　　　
吉野 陸; 盛田 雅人
第14回 CSJ化学フェスタ2024, 24 Oct. 2024
20241022, 20241024

ベンゾチアゾール骨格を基本骨格とするπ共役発光分子のドナー性評価　　　　　　　　　　　　　　　
望月 百々花; 盛田 雅人
第14回 CSJ化学フェスタ2024, 23 Oct. 2024
20241022, 20241024

Nov. 2024 - Feb. 2025
茨城大学大学院

Exercise in Applied Chemistry Ⅱ　　　　　　　　　　　　　　　
Nov. 2024 - Feb. 2025
Ibaraki University

Basic Organic Chemistry Ⅲ　　　　　　　　　　　　　　　
Nov. 2024 - Feb. 2025
Ibaraki University

Sep. 2024 - Nov. 2024
茨城大学大学院

Organic Chemistry Ⅲ　　　　　　　　　　　　　　　
Sep. 2024 - Nov. 2024
Ibaraki University

Experiment of Applied Chemistry Ⅰ　　　　　　　　　　　　　　　
Apr. 2024 - Aug. 2024
Ibaraki University

Basic Experiment of Material Science Ⅰ　　　　　　　　　　　　　　　
Apr. 2024 - Aug. 2024
Ibaraki University

Feb. 2025 - Present, 光化学協会

Aug. 2024 - Present, 日本フッ素化学会

Apr. 2024 - Present, 日本化学会

Arene-Perfluoroarene相互作用を利用したカラムナー積層体の開発　　　　　　　　　　　　　　　
茨城大学
Apr. 2025 - Mar. 2026

巨大電気化学ゼーベック係数材料系創出を目指した酸化還元対エンジニアリング　　　　　　　　　　　　　　　
Apr. 2025 - Mar. 2026

ベンゾチアゾール型室温固体りん光体の開発　　　　　　　　　　　　　　　
茨城大学
Apr. 2025 - Mar. 2026

非共有結合性相互作用を活用した初期形状記憶型パッケージフィルム材料の開発　　　　　　　　　　　　　　　
茨城大学
Nov. 2024 - Mar. 2026

ハロゲン結合を利用した重金属を含まない効率的な近赤外発光材料の創製
特別研究員奨励費
京都工芸繊維大学
Apr. 2021 - Mar. 2023