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National Institute of Advanced Industrial Science and Technology (AIST)
organometallics coordination chemistry silicon chemistry
Scopus Publications
Shinji Tanaka, Shingo Takada, Tohru Suzuki, Yumiko Nakajima, and Kazuhiko Sato
Macromolecules, ISSN: 00249297, eISSN: 15205835, Pages: 2806-2812, Published: 12 April 2022
American Chemical Society (ACS)
Nai-Yuan Jheng, Yusuke Ishizaka, Yuki Naganawa, Yasunori Minami, Akira Sekiguchi, Kosuke Iizuka, and Yumiko Nakajima
ACS Catalysis, eISSN: 21555435, Pages: 2320-2329, Published: 18 February 2022
American Chemical Society (ACS)
Yuki Naganawa, Yumiko Nakajima, Shigeyoshi Sakaki, and Hajime Kameo
European Journal of Organic Chemistry, ISSN: 1434193X, eISSN: 10990690, Volume: 2022, Published: 11 February 2022
Wiley
Shinji Tanaka, Yumiko Nakajima, Atsuko Ogawa, Takashi Kuragano, Yoshihiro Kon, Masanori Tamura, Kazuhiko Sato, and Christophe Copéret
Chemical Science, ISSN: 20416520, eISSN: 20416539, Published: 2022
Royal Society of Chemistry (RSC)
We demonstrated that DNP-enhanced NMR spectroscopy enables the direct and detailed characterization of polymer-supported alkylammonium catalysts.
Shinji Tanaka, Junichi Sato, and Yumiko Nakajima
Green Chemistry, ISSN: 14639262, eISSN: 14639270, Pages: 9412-9416, Published: 7 December 2021
Royal Society of Chemistry (RSC)
A strategy of capturing ethylene glycol with dimethyl carbonate in the catalytic methanolysis of polyethylene terephthalate enabled depolymerization at ambient temperature.
Koya Inomata, Yuki Naganawa, Zhi An Wang, Kei Sakamoto, Kazuhiro Matsumoto, Kazuhiko Sato, and Yumiko Nakajima
Communications Chemistry, eISSN: 23993669, Published: December 2021
Springer Science and Business Media LLC
AbstractThe transition-metal-catalysed hydrosilylation reaction of alkenes is one of the most important catalytic reactions in the silicon industry. In this field, intensive studies have been thus far performed in the development of base-metal catalysts due to increased emphasis on environmental sustainability. However, one big drawback remains to be overcome in this field: the limited functional group compatibility of the currently available Pt hydrosilylation catalysts in the silicon industry. This is a serious issue in the production of trichloro(3-chloropropyl)silane, which is industrially synthesized on the order of several thousand tons per year as a key intermediate to access various silane coupling agents. In the present study, an efficient hydrosilylation reaction of allyl chloride with trichlorosilane is achieved using the Rh(I) catalyst [RhCl(dppbzF)]2 (dppbzF = 1,2-bis(diphenylphosphino)-3,4,5,6-tetrafluorobenzene) to selectively form trichloro(3-chloropropyl)silane. The catalyst enables drastically improved efficiency (turnover number, TON, 140,000) and selectivity (>99%) to be achieved compared to conventional Pt catalysts.
Monika Gautam, Shinji Tanaka, Akira Sekiguchi, and Yumiko Nakajima
Organometallics, ISSN: 02767333, eISSN: 15206041, Pages: 3697-3702, Published: 22 November 2021
American Chemical Society (ACS)
Yasunori Minami, Yumiko Nakajima, Nao Matsuyama, Yasuaki Matsuo, Masanori Tamura, and Kazuhiko Sato
Synthesis (Germany), ISSN: 00397881, eISSN: 1437210X, Pages: 3351-3354, Published: 16 September 2021
Georg Thieme Verlag KG
AbstractThe solvent-insoluble poly(phenylene sulfide) main chain was reductively cleaved by using triethylsilane as a hydrogen source under palladium/IcHex catalytic conditions. After the reaction, benzene and bis(triethylsilyl) sulfide as a sulfide source were formed efficiently. This method could be operated on a gram scale.
Yumiko Nakajima, Tomohiro Takeshita, and Nai-Yuan Jheng
Dalton Transactions, ISSN: 14779226, eISSN: 14779234, Pages: 7532-7536, Published: 14 June 2021
Royal Society of Chemistry (RSC)
A metal–ligand cooperation (MLC) behavior was investigated using Iron and cobalt complexes bearing a phenanthroline-based meridional PNNP ligand, demonstrating a unique long-range MLC, where the phenanthroline backbone behaves as a H2 reservoir.
Yasunori Minami, Hitomi Miyamoto, and Yumiko Nakajima
ChemCatChem, ISSN: 18673880, eISSN: 18673899, Pages: 855-858, Published: 5 February 2021
Wiley
Furfural and its derivatives underwent alkenylation with alkynes via α‐C−H activation in the presence of a palladium/carboxylic acid catalyst to give the corresponding single and double alkenylated products. The reactive aldehyde group remained intact during this reaction. This catalytic system allowed selective alkenylation of furan substrates having electron‐withdrawing substituents.
Yuki Naganawa, Kei Sakamoto, and Yumiko Nakajima
Organic Letters, ISSN: 15237060, eISSN: 15237052, Pages: 601-606, Published: 15 January 2021
American Chemical Society (ACS)
Direct catalytic transformation of chlorosilanes into organosilicon compounds remains challenging due to difficulty in cleaving the strong Si-Cl bond(s). We herein report the palladium-catalyzed cross-coupling reaction of chlorosilanes with organoaluminum reagents. A combination of [Pd(C3H5)Cl]2 and DavePhos ligand catalyzed the selective methylation of various dichlorosilanes 1, trichlorosilanes 5, and tetrachlorosilane 6 to give the corresponding monochlorosilanes.
Nai-Yuan Jheng, Yusuke Ishizaka, Yuki Naganawa, Akira Sekiguchi, and Yumiko Nakajima
Dalton Transactions, ISSN: 14779226, eISSN: 14779234, Pages: 14592-14597, Published: 7 November 2020
Royal Society of Chemistry (RSC)
A cobalt(i) alkyl complex bearing a tetradentate phenanthroline-based PNNP ligand undergoes dearomatization of the ligand backbone skeleton upon heating and furthermore achieves H–H bond cleavage.
Jian-Qiu Zhang, Eiichi Ikawa, Hiroyoshi Fujino, Yuki Naganawa, Yumiko Nakajima, and Li-Biao Han
Journal of Organic Chemistry, ISSN: 00223263, eISSN: 15206904, Pages: 14166-14173, Published: 6 November 2020
American Chemical Society (ACS)
Sodium exhibits better efficacy and selectivity than Li and K for converting Ph3P(O) to Ph2P(OM). The destiny of PhNa co-generated is disclosed. A series of alkyl halides R4X and aryl halides ArX all react with Ph2P(ONa) to produce the corresponding phosphine oxides in good to excellent yields.
Takahiro Kawatsu, Keiya Aoyagi, Yumiko Nakajima, Jun-Chul Choi, Kazuhiko Sato, and Kazuhiro Matsumoto
Organometallics, ISSN: 02767333, eISSN: 15206041, Pages: 2947-2950, Published: 24 August 2020
American Chemical Society (ACS)
Herein, we describe a decarboxylative approach to the preparation of alkynylsilanes. Treatment of a silyl alkynoate in N,N-dimethylformamide (DMF) at 80 °C in the presence of catalytic amounts of C...
Ryota Watanabe, Aki Sugahara, Hideaki Hagihara, Kei Sakamoto, Yumiko Nakajima, and Yuki Naganawa
ACS Omega, eISSN: 24701343, Pages: 12431-12439, Published: 2 June 2020
American Chemical Society (ACS)
Simultaneous improvement in the mechanical properties and lifetime of polymer nanocomposites is crucially significant to further extend the versatility of polymer materials and reduce environmental impact. In this study, we fabricated reinforced polypropylene (PP)-based nanocomposites with improved aging stability by the addition of surface-modified well-ordered silica nanospheres with a silane coupling agent (SCA) containing hindered phenol antioxidant as a filler. Uniform grafting of the SCA on the filler surface contributed to homogeneous dispersion of the filler into the matrix, leading to improved properties (e.g., stiffness and ductility) and uniform distribution of the antioxidant component into the entire nanocomposite by filler dispersion. The grafting of SCA also likely provides an inhibitory effect on antioxidant migration, which leads to loss of polymer stability during the aging process. This novel idea for the material design of PP-based nanocomposites, which simultaneously enhances their mechanical properties and lifetime, is promising for application in the fabrication of various types of polymer nanocomposites.
Yuki Naganawa, Koya Inomata, Kazuhiko Sato, and Yumiko Nakajima
Tetrahedron Letters, ISSN: 00404039, eISSN: 18733581, Published: 12 March 2020
Elsevier BV
Abstract Hydrosilylation of alkenes is an important reaction for the production of organosilicon compounds such as industrially important silicones and silane coupling agents. To synthesize highly sophisticated organosilicon materials, it is of great importance to develop novel hydrosilylation catalysts with good compatibility towards a wide range of functional groups. This review highlights the main advances made in this area. Efforts to develop Pt catalysis systems as well as environmentally benign base-metal catalyst systems have been collected with the aim of providing a comprehensive overview of the subject from the viewpoint of both academia and industry.
Monika Gautam, Takafumi Yatabe, Shinji Tanaka, Naoto Satou, Tomohiro Takeshita, Kazuya Yamaguchi, and Yumiko Nakajima
ChemistrySelect, eISSN: 23656549, Pages: 15-17, Published: 9 January 2020
Wiley
Hiromu Hosoya, Luis C. Misal Castro, Ibrahim Sultan, Yumiko Nakajima, Toshimichi Ohmura, Kazuhiko Sato, Hayato Tsurugi, Michinori Suginome, and Kazushi Mashima
Organic Letters, ISSN: 15237060, eISSN: 15237052, Pages: 9812-9817, Published: 20 December 2019
American Chemical Society (ACS)
4,4'-Bipyridyl worked as an organocatalyst for the reduction of nitroarenes by bis(neopentylglycolato)diboron (B2nep2), followed by hydrolysis to give the corresponding anilines. This reduction proceeded under aerobic conditions without any prepurification of substrates and reagents. We found broad functional group tolerance and compatibility for O- and N-protecting groups under the reaction conditions. The key in this catalytic system was the addition of B2nep2 to 4,4'-bipyridyl to form N,N'-bis[(neopentylglycolato)boryl]-4,4'-bipyridinylidene as a deoxygenating reagent of nitroarenes.
Koya Inomata, Yuki Naganawa, Haiqing Guo, Kazuhiko Sato, and Yumiko Nakajima
Tetrahedron Letters, ISSN: 00404039, eISSN: 18733581, Published: 10 October 2019
Elsevier BV
Abstract Reactions of allyl-functionalized poly(ethylene glycol) (PEG) derivatives with alkoxysilanes proceeded efficiently to furnish the corresponding hydrosilylated products in good to excellent yields using a ruthenium catalyst, [RuCl2(nbd)]n. A preliminary mechanistic study supported the pivotal role of the PEG moiety, which coordinated to the ruthenium atom during the reaction to achieve high reaction selectivity. This method may be applicable to the synthesis of various PEGs with a silyl terminus, which is useful as biocompatible and low toxic silane coupling agents. .
Yuki Naganawa, Haiqing Guo, Kei Sakamoto, and Yumiko Nakajima
ChemCatChem, ISSN: 18673880, eISSN: 18673899, Pages: 3756-3759, Published: 21 August 2019
Wiley
Nickel‐catalyzed cross‐coupling reactions of chlorosilanes with organoaluminum reagents were developed. An electron‐rich Ni(0)/PCy3 complex was found to be an effective catalyst for the desired transformation. The reaction of dichlorosilanes 1 proceeded to give the corresponding monosubstituted products 2. Trichlorosilanes 4 underwent selective double substitution to furnish the corresponding monochlorosilanes 2. Overall, the selective synthesis of a series of alkylmonochlorosilanes 2 from di‐ and trichlorosilanes was achieved using the present catalytic systems.
Yusuke Ishizaka and Yumiko Nakajima
Organometallics, ISSN: 02767333, eISSN: 15206041, Pages: 888-893, Published: 25 February 2019
American Chemical Society (ACS)
A cobalt dialkyl with an N-heterocyclic carbene [Co(CH2SiMe3)2(IPr)] (IPr = 1,3-bis(2,6-diisopropylphenyl)imidazole-2-ylidene) underwent successive Si–H bond cleavage of hydrosilanes. The reaction paths were highly dependent on the bulkiness of the hydrosilanes, which led to the formation of various μ-silyl-bridged dicobalt complexes, [{Co(IPr)}2(μ-SiH2Hex)4], [{Co(IPr)}2(μ-SiH2Ph)3(H)3], and [{Co(IPr)}2(μ-SiHPh2)(μ-H)2].
Keiya Aoyagi, Kazuhiro Matsumoto, Shigeru Shimada, Kazuhiko Sato, and Yumiko Nakajima
Organometallics, ISSN: 02767333, eISSN: 15206041, Pages: 210-212, Published: 28 January 2019
American Chemical Society (ACS)
The catalytic reduction of alkoxysilanes with the borane HBpin (pin = pinacolato) was achieved using a metallocene-type yttrium complex as a catalyst precursor. Mechanistic study supported the pivotal role of the rigid metallocene structure of the catalyst, which bears two bulky η5-C5Me4SiMe3 ligands, in suppressing the coordination of the side product MeOBpin that is generated during the reaction.
Keiya Aoyagi, Yu Ohmori, Koya Inomata, Kazuhiro Matsumoto, Shigeru Shimada, Kazuhiko Sato, and Yumiko Nakajima
Chemical Communications, ISSN: 13597345, eISSN: 1364548X, Pages: 5859-5862, Published: 2019
Royal Society of Chemistry (RSC)
Hydrosilanes were synthesized by reduction of alkoxysilanes with BH3 in the presence of hexamethylphosphoric triamide (HMPA) as a Lewis-base catalyst. The reaction was also achieved using an inexpensive and easy-to-handle handled hydride source NaBH4, which reacted with EtBr as a sacrificial reagent to form BH3in situ.
Chemistry Letters, ISSN: 03667022, eISSN: 13480715, Pages: 364-366, Published: 2019
Yuki Naganawa, Yoshifumi Maegawa, Haiqing Guo, Sandeep Suryabhan Gholap, Shinji Tanaka, Kazuhiko Sato, Shinji Inagaki, and Yumiko Nakajima
Dalton Transactions, ISSN: 14779226, eISSN: 14779234, Pages: 5534-5540, Published: 2019
Royal Society of Chemistry (RSC)
A platinum complex immobilized on a bipyridine-periodic mesoporous organosilica (BPy-PMO) effectively catalysed the hydrosilylation reaction and showed good reusability without the loss of the product yield.