研　究

研究展望

　 我々の研究室では、有機合成化学、有機金属化学、ヘテロ元素化学、物理化学、分子集合体化学、液晶科学を基盤にして、発光機能、電荷輸送機能、液晶性などの機能を性能良く発揮する有機低分子、高分子、および超分子の創製に取り組んでいます。研究テーマは、大別すると以下の4つに分類されます。

（1）標的とする機能性分子を効率よく合成する有機合成反応、反応剤および合成戦略の開発

（2）分子凝集状態での高効率発光を特徴とする有機発光材料の設計、合成、評価と機能開発

（3）高速電荷輸送性を発揮する有機半導体材料の開発

（4）異方発光性を特徴とする複合液晶材料の開発

　有機合成法の革新をめざすテーマ（１）と機能性分子の創製という研究テーマ（２）〜（４）は、一見それぞれ関係ないように見えますが、我々の研究活動ではこの両者は密接につながっています。というのも、新しい合成法が開発されると、そのおかげで従来の有機合成法では手にすることのできなかった（あるいは手にすることがとても難しかった）化合物群が簡単に入手できるようになります。つまり、新合成法によって分子設計の可能性が大きく拡がるのです。また、独自の着想によって新しい機能性分子を設計しても（着想しても）、現在知られている有機合成法では簡単に合成できない場面にしばしば遭遇します。そのような場合には、新しい分子設計に応えるための反応・合成法開発が必要になり、そのことが合成法開拓の研究に新しいテーマを与えてくれることになります。このように、我々の研究室では、合成法の革新と機能性分子の創製を両輪にして研究を展開しています。

これまでの主な研究成果

• 有機金属化学を基盤とする有機合成法の開発
• 機能性有機分子の設計、合成および物性評価

最近の研究発表・学術出版

• Organic fluorophores that emit ultraviolet light in the aggregated state. Shimizu, M.; Sakurai, T., Aggregatehttps://doi.org/10.1002/agt2.144.
• The Journey to Precious-Metal-Free Organic Phosphors from Single-Benzene-Cored Fluorophores. Shimizu, M., Chem. Rec. 2021, 21 (6), 1489–1505.
• Metal-Free Organic Luminophores that Exhibit Dual Fluorescence and Phosphorescence Emission at Room Temperature. Shimizu, M.; Sakurai, T., ChemPlusChem 2021, 86 (3), 446–459.
• Remarkable Increase of Fluorescence Quantum Efficiency by Cyano Substitution on an ESIPT Molecule 2-(2-Hydroxyphenyl)benzothiazole: A Highly Photoluminescent Liquid Crystal Dopant. Sakurai, T.; Kobayashi, M.; Yoshida, H.; Shimizu, M., Crystals 2021, 11 (9), 1105.
• Efficient Emission of Ultraviolet Light by Solid State Organic Fluorophores: Synthesis and Characterization of 1,4-Dialkeny-2,5-dioxybenzenes. Shimizu, M.; Nishimura, K.; Hirakawa, R.; Sakurai, T., Chem. Eur. J. 2021, 27 (5), 1626–1637.
• Dual Emission from Precious Metal-Free Luminophores Consisting of C, H, O, Si, and S/P at Room Temperature. Shimizu, M.; Nagano, S.; Kinoshita, T., Chem. Eur. J. 2020, 26 (23), 5162–5167.
• Palladium-Catalyzed Annulation of Phenazastannines with 9-(Dibromomethylene)fluorene and -(thio)xanthenes: Facile Synthesis of Acridine Moiety-Containing Bis(tricyclic) Aromatic Enes. Shimizu, M.; Nishimura, K.; Mineyama, M.; Fuji, H., Org. Process Res. Dev. 2019, 23 (8), 1740–1745.
• 4,5-Diaminophthalimides: highly efficient solid-state fluorophores and turn-on type fluorescent probes for hydrazine. Shimizu, M.; Tamagawa, T.; Nishimura, K., Mater. Chem. Front. 2019, 3 (4), 563–570.
• (Poly)terephthalates with Efficient Blue Emission in the Solid State. Shimizu, M.; Shigitani, R.; Kinoshita, T.; Sakaguchi, H., Chem. Asian J. 2019, 14 (10), 1792–1800.
• Shimizu, M., Precious Metal-Free Organic Small Molecule Luminophores That Exhibit Room Temperature Phosphorescence. In Principles and Applications of Aggregation-Induced Emission, Tang, Y.; Tang, B. Z., Eds. Springer International Publishing: Cham, 2019; pp 43–76.
• Luminescent solar concentrators: boosted optical efficiency by polymer dielectric mirrors. Iasilli, G.; Francischello, R.; Lova, P.; Silvano, S.; Surace, A.; Pesce, G.; Alloisio, M.; Patrini, M.; Shimizu, M.; Comoretto, D.; Pucci, A., Mater. Chem. Front. 2019, 3 (3), 429–436.
• A trigonal molecular assembly system with the dual light-driven functions of phase transition and fluorescence switching. Abe, I.; Hara, M.; Seki, T.; Cho, S. J.; Shimizu, M.; Matsuura, K.; Cheong, H.-K.; Kim, J. Y.; Oh, J.; Jung, J.; Han, M., J. Mater. Chem. C 2019, 7 (8), 2276–2282.
• Aggregation-induced emission and thermally activated delayed fluorescence of 2,6-diaminobenzophenones. Shimizu, M.; Nakatani, M.; Nishimura, K., Sci. China Chem. 2018, 61 (8), 925–931.
• Use of silylmethoxy groups as inducers of efficient room temperature phosphorescence from precious-metal-free organic luminophores. Shimizu, M.; Kinoshita, T.; Shigitani, R.; Miyake, Y.; Tajima, K., Mater. Chem. Front. 2018, 2 (2), 347–354.
• Shimizu, M., Silole-Based Materials in Optoelectronics and Sensing. In Main Group Strategies Towards Functional Hybrid Materials, Baumgartner, T.; Jäkle, F., Eds. John Wiley & Sons Ltd.: 2018; pp 163–195.
• Blue-to-Green Delayed Fluorescence of 2-Aminoisophthalic Acid Diesters Dispersed in Polymer Film. Shimizu, M.; Nakatani, M., Eur. J. Org. Chem. 2017, (32), 4695–4702.
• Germanium-Bridged 2-Phenylbenzoheteroles as Luminophores Exhibiting Highly Efficient Solid-State Fluorescence. Shimizu, M.; Ryuse, D.; Kinoshita, T., Chem. Eur. J. 2017, 23 (58), 14623–14630.
• A push-pull silafluorene fluorophore for highly efficient luminescent solar concentrators. Gianfaldoni, F.; De Nisi, F.; Iasilli, G.; Panniello, A.; Fanizza, E.; Striccoli, M.; Ryuse, D.; Shimizu, M.; Biver, T.; Pucci, A., RSC Adv. 2017, 7 (59), 37302–37309.
• Aggregation-Induced Orange-to-Red Fluorescence of 2,5-Bis(diarylamino)terephthalic Acid Dithioesters. Shimizu, M.; Fukui, H.; Natakani, M.; Sakaguchi, H. Eur. J. Org. Chem. 2016, 5950-5956.
• Copper-Catalyzed Double S-Arylation of Potassium Thioacetate with Dibenziodolium Triflates: Facile Synthesis of Unsymmetrical Dibenzothiophenes. Shimizu, M.; Ogawa, M.; Tamagawa, T.; Shigitani, R.; Nakatani, M.; Nakano, Y., Eur. J. Org. Chem. 2016, (16), 2785–2788.
• Siloxy Group-Induced Highly Efficient Room Temperature Phosphorescence with Long Lifetime. Shimizu, M.; Shigitani, R.; Nakatani, M.; Kuwabara, K.; Miyake, Y.; Tajima, K.; Sakai, H.; Hasobe, T., J. Phys. Chem. C 2016, 120 (21), 11631–11639.
• A Native-Chemical-Ligation-Based Turn-on Fluorescent Probe for Selective Detection of Cysteine. Shimizu, M.; Fukui, H.; Shigitani, R., J. Chin. Chem. Soc. 2016, 63 (4), 317–322.
• Assembly of an Achiral Chromophore into Light-Responsive Helical Nanostructures in the Absence of Chiral Components, Han, M.; Cho, S. J.; Norikane, Y.; Shimizu, M.; Seki, T., Chem. Eur. J. 2016, 22, 3971-3975.
• Room-Temperature Phosphorescence of Crystalline 1,4-Bis(aroyl)-2,5-dibromobenzenes, Masaki Shimizu, Akinori Kimura, and Hiroshi Sakaguchi, Eur. J. Org. Chem. 2016, 467–473.
• Development of Organic Chromophores That Exhibit Efficient Visible-Light Emission in the Solid State, Masaki Shimizu, 7th East Asia Symposium on Functional Dyes and Advanced Materials, Osaka, Japan.
• Design and Characterization of Laterally Substituted D-pi-A Type Biphenyls as Fluorescent Solid, Tomokazu Tamagawa and Masaki Shimizu, 7th East Asia Symposium on Functional Dyes and Advanced Materials, Osaka, Japan.
• Luminescent Properties of 2,5-Dialkoxyterephthalic Acid Diesters, Ryosuke Shigitani and Masaki Shimizu, 7th East Asia Symposium on Functional Dyes and Advanced Materials, Osaka, Japan.
• Crystallization–Induced Room Temperature Phosphorescence of 1,4-Bis(aroyl)-2,5-Dibromobenzenes, Masaki Shimizu, Akinori Kimura, and Hiroshi Sakaguchi, The 6th International Symposium of Advanced Energy Science -Towards the Realization of Zero-Emission Energy-, Kyoto, Japan.
• Design and Characterization of 4,5-Diaminoterephthalic Acid Diesters as Blue Emissive Solids, M. Shimizu, T. Tamagawa, 7th Spanish-Portuguese-Japanese Organic Chemistry Sympsoium, Seville, Spain.
• Dibenzosiloles and 12H-Indololo[3,2-d]naphtho[1,2-b][1]siloles: Exploration of Organic Chromophores Exhibiting Efficient Solid-State Fluorescence. Shimizu, M., Chem. Rec. 2015, 15, 73–85.
• Design and Characterization of 4,5-Bis(diarylamino)phthalic Acid Diesters as a New Class of Fluorophores Exhibiting Efficient Blue Emission in the Solid State. Shimizu, M.; Tamagawa, T., Eur. J. Org. Chem. 2015, 291–295.