研究者詳細 - 西原　康師

論文 - 西原　康師

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Copper-catalyzed Regioselective Chloroamination of Alkenes with Chlorotrimethylsilane and N-Fluorobenzenesulfonimide under Microwave-assisted Conditions 査読

Masayuki Iwasaki, Jie Xu, Yukari Tani, Liyan Fu, Yuichi Ikemoto, Yasuyuki Ura, Yasushi Nishihara

Chemistry Letters 48 ( 3 ) 281 - 284 2019年3月

Synthesis and Physicochemical Properties of Dibenzo[2,3-d:2′,3′-d′]anthra[1,2-b:5,6-b′]dithiophene (DBADT) and Its Derivatives: Effect of Substituents on Their Molecular Orientation and Transistor Properties 査読

Keita Hyodo, Shuhei Nishinaga, Yuta Sawanaka, Takumi Ishida, Hiroki Mori, Yasushi Nishihara

The Journal of Organic Chemistry 84 ( 2 ) 698 - 709 2019年1月

Vinylene-bridged difluorobenzo[c][1,2,5]-thiadiazole (FBTzE): a new electron-deficient building block for high-performance semiconducting polymers in organic electronics 査読

Yuya Asanuma, Hiroki Mori, Ryosuke Takahashi, Yasushi Nishihara

Journal of Materials Chemistry C 7 ( 4 ) 905 - 916 2019年1月

Nickel-catalysed decarbonylative borylation of aroyl fluorides 査読

Zhenhua Wang, a, Xiu Wanga, Yasushi Nishihara

Chemical Communications 54 ( 99 ) 13969 - 13972 2018年11月

Development of a Phenanthrodithiophene-Difluorobenzoxadiazole Copolymer Exhibiting High Open-Circuit Voltage in Organic Solar Cells 査読

Hiroki Mori, Ryosuke Takahashi, Yasushi Nishihara

J. Poly. Sci. Part A: Pol. Chem. 56 ( 23 ) 2646 - 2655 2018年10月

Nickel-Catalyzed Decarbonylative Alkylation of Aroyl Fluorides Assisted by Lewis-Acidic Organoboranes 査読

Yasuhiro Okuda, Jie Xu, Takumi Ishida, Chen-an Wang, Yasushi Nishihara

ACS Omega 3 ( 10 ) 13129 - 13140 2018年10月

Synthesis and Transistor Characteristics of Dinaphtho[2,3-d:2’,3’-d’]anthra[1,2-b:5,6-b’]dithiophene (DNADT) 査読

Shuhei Nishinaga, Yuta Sawanaka, Ryota Toyama, Takumi Ishida, Hiroki Mori, Yasushi Nishihara

Chem. Lett. 47 ( 11 ) 1409 - 1411 2018年9月

Efficient Synthesis and Properties of [1]Benzothieno[3,2-b ]thieno[2,3-d ]furans and [1]Benzothieno[3,2-b ]thieno[2,3-d ]thiophenes 査読

Yuji Kurimoto, Koichi Mitsudo, Hiroki Mandai, Atsushi Wakamiya, Yasujiro Murata, Hiroki Mori, Yasushi Nishihara, Seiji Suga

Asian Journal of Organic Chemistry 7 ( 8 ) 1635 - 1641 2018年8月

Alkoxy-Substituted Anthra[1,2-c:5,6-c’]bis([1,2,5]-thiadiazole) (ATz): a New Electron-Acceptor Unit in the Semiconducting Polymers for Organic Electronics 査読

Hiroki Mori, Shuhei Nishinaga, Ryosuke Takahashi, Yasushi Nishihara

Macromolecules 51 5473 - 5484 2018年6月

Regioselective Synthesis of γ‑Lactones by Iron-Catalyzed Radical Annulation of Alkenes with α‑Halocarboxylic Acids and Their Derivatives 査読

Masayuki Iwasaki, Natsumi Miki, Yuichi Ikemoto, Yasuyuki Ura, Yasushi Nishihara

Org. Lett. 20 3848 - 3852 2018年6月

Low-bandgap semiconducting polymers based on sulfur-containing phenacene-type molecules for transistor and solar cell applications 査読

Hiroki Mori, Yasushi Nishihara

Polymer Journal 50 1 - 11 2018年5月

担当区分：最終著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Nature Publishing Group

The incorporation of a highly extended π-electron system into a polymer backbone is an effective strategy to develop high-performance donor–acceptor (D–A) polymers suitable for organic electronics because this strategy can facilitate a dense π-π stacking structure, leading to efficient carrier transport. With this in mind, we developed phenanthro[1,2-b:8,7-b′]dithiophene (PDT) because this new phenacene-type molecule has a highly crystalline nature, deep HOMO level, and high hole mobility, which are characteristics known to be suitable for a donor unit in high-performance D–A polymers. In this focus review, we report recent progress in PDT-containing D-A polymers combined with various strong acceptor units. Incorporation of PDT into a polymer backbone results in deep HOMO energy levels of −5.4~−5.5 eV, strong aggregation, and a dense packing structure with a short π-stacking distance of 3.5~3.6 Å. PDT-based polymers with appropriate alkyl side chains exhibit high hole mobilities of up to 0.18 cm2 V−1 s−1 in organic field-effect transistor (OFET) devices due to their tendency to form highly ordered edge-on structures. Furthermore, we can adjust their level of molecular orientation from edge-on to face-on by increasing their molecular weight, leading to a high power conversion efficiency of over 6% in polymer solar cell (PSC) applications. These results demonstrate that PDT is a good candidate as a high-performance building block in D-A polymers.

DOI： 10.1038/s41428-018-0072-4

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Efficient Synthesis and Properties of [1]Benzothieno[3,2-b]thieno[2,3-d]furans and [1]Benzothieno[3,2-b]thieno[2,3-d]thiophenes 査読

Yuji Kurimoto, Koichi Mitsudo, Hiroki Mandai, Atsushi Wakamiya, Yasujiro Murata, Hiroki Mori, Yasushi Nishihara, Seiji Suga

Asian J. Org. Chem. 7 1635 - 1641 2018年5月

Effect of Substitution Positions of Alkyl Side Chains in Phenanthrodithiophene–Isoindigo Copolymers: The Enhancement of Crystallinity and Control of Molecular Orders 査読

Hiroki Mori, Shuto Hara, Ryota Toyama, Yuya Asanuma, Ryosuke Takahashi, Shuhei Nishinaga, Yasushi Nishihara

J. Poly. Sci. Part A: Pol. Chem. 56 1757 - 1767 2018年5月

Phenanthrodithiophene (PDT)-Difluorobenzothiadiazole (DFBT) Copolymers: Effect on Molecular Orientation and Solar Cell Performance of Alkyl Substitution onto a PDT Core 査読

Hiroki Mori, Ryosuke Takahashi, Keita Hyodo, Shuhei Nishinaga, Yuta Sawanaka, Yasushi Nishihara

Macromolecules 51 ( 4 ) 1357 - 1369 2018年2月

担当区分：最終著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：American Chemical Society

Synthesis, characterization, and solar cell application of three 4,7-dialkylated phenanthro[1,2-b:8,7-b′]dithiophene (PDT)-difluorobenzothiadiazole (DFBT copolymers (P1-P3) with different linear alkyl side chains to improve solubility, molecular weight, and molecular orientation are described. The utilization of Ir-catalyzed direct borylation and sequential functionalization can selectively afford the target 4,7-dialkylated PDT as the monomers. Migita-Kosugi-Stille coupling in the presence of CuI can accelerate polymerization to afford high-molecular-weight polymers along with their improved solubility. The effect of alkyl substitution at the 4,7-positions on the electronic structure of PDT-DFBT copolymers is negligible. By installation of additional alkyl chains at the 4,7-positions of PDT, the synthesized polymers P1-P3 have lower intermolecular interaction than that of nonalkylated P0, but they still maintained aggregation behavior in solution. In addition, they formed a favorable face-on orientation with a short π-stacking distance of 3.6 Å, which can enhance their carrier transport ability, resulting in high Jsc and FF. As a result, their fabricated solar cells reached a PCE exceeding 6%, which are about 1.7-fold higher than that of P0. Comparison of alkyl side chain length at the 4,7-positions of PDT revealed that all polymers formed a predominantly face-on orientation and have a similar face-on ratio in blended films, but their crystallinity was decreased as the carbon chains at the 4,7-positions of PDT became shorter. On the other hand, the polymers with short alkyl side chains tended to have low surface roughness and small domain size of active layers, which is an ideal phase separation structure for high-performance PSCs. From these results, it could be seen that the polymers have a trade-off relationship between their domain size and crystallinity, but the impact of alkyl side chain length on their photovoltaic properties is rather small. Thus, the construction of face-on orientation is highly important to achieve a high PCE. Among three polymers, the P3/PC61BM-based solar cell with an optimal nanoscale phase separation structure with bicontinuous domain showed the highest PCE of up to 6.6%.

DOI： 10.1021/acs.macromol.7b02734

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Synthesis of a 1,2-Dithienylethene-Containing Donor-Acceptor Polymer via Palladium-Catalyzed Direct Arylation Polymerization (DArP) 招待査読

Masayuki Wakioka, Natsumi Yamashita, Hiroki Mori, Yasushi Nishihara, Fumiyuki Ozawa

Molecules 23 ( 4 ) 981 - 990 2018年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：MDPI AG

This paper reports the synthesis of D-A polymers containing 1,2-dithienylethene (DTE) units via palladium-catalyzed direct arylation polymerization (DArP). The reaction of dibromoisoindigo (1-Br) and DTE (2-H), in the presence of Pd2(dba)3·CHCl3 (0.5 mol%), P(2-MeOC6H4)3 (L1) (2 mol%), pivalic acid (1 equiv) as catalyst precursors, and Cs2CO3 (3 equiv) as a base affords poly(1-alt-2) with a high molecular weight (Mn up to 44,900). Although, it has been known that monomers, with plural C–H bonds, tend to form insoluble materials via direct arylation at undesirable C–H positions
the reaction of 1-Br and 2-H cleanly proceeds without insolubilization. The resulting polymer has a well-controlled structure and exhibits good charge transfer characteristics in an organic field-effect transistor (OFET), compared to the polymer produced by Migita–Kosugi–Stille cross-coupling polymerization. The DArP product displays an ideal linear relationship in the current–voltage curve, whereas the Migita–Kosugi–Stille product shows a VG-dependent change in the charge mobility.

DOI： 10.3390/molecules23040981

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Synthesis and Transistor Application of Bis[1]benzothieno[6,7?d:6',7'?d']benzo[1,2-b:4,5-b']dithiophenes 査読

Shuhei Nishinaga, Hiroki Mori, Yasushi Nishihara

The Journal of Organic Chemistry 83 5506 - 5515 2018年

Direct Thiolation and Selenation of Aryl C─H Bonds Catalyzed by Palladium or Nickel 査読

Masayuki Iwasaki, Yasushi Nishihara

J. Syn. Org. Chem. Jpn. (Yuki Gosei Kagaku Kyokaishi) 76 ( 1 ) 11 - 20 2018年

Phenanthrene Synthesis by Palladium-Catalyzed Benzannulation with o-Bromobenzyl Alcohols through Multiple Carbon–Carbon Bond Formations 査読

Masayuki Iwasaki, Yasuhiro Araki, Yasushi Nishihara

J. Org. Chem. 82 ( 12 ) 6242 - 6258 2017年6月

Solar Cell Performance of Phenanthrodithiophene-Isoindigo Copolymers Depends on Their Thin-Film Structure and Molecular Weight 査読

Hiroki Mori, Shuto Hara, Shuhei Nishinaga, Yasushi Nishihara

MACROMOLECULES 50 ( 12 ) 4639 - 4648 2017年6月

担当区分：最終著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER CHEMICAL SOC

Phenanthro[1,2-b:8,7-b']dithiophene (PDT)isoindigo (IID)-based polymers 12OD (L) and 12OD (H) with a different molecular weight were synthesized and characterized. By using further purified PDT and IID monomers, the high-molecular-weight polymer 12OD (H) with number-average molecular weight (M-n) over 50 kDa was obtained. Both 12OD (L) and 12OD (H) polymers have the same energy gap and highest occupied molecular orbital (HOMO) energy levels, indicating that the influence of molecular weight on their electronic structure is negligible, although 12OD (H) has stronger aggregation behavior than 12OD (L). 12OD (H)-based solar cells fabricated by using optimal solvent and additives showed an increased short-circuit current density (J(sc)) with same open-circuit voltage (V-oc) and fill factor (FF), resulting in a significantly improved power conversion efficiency (PCE) of up to 6.1%, which is approximately 70% higher than that of the 12OD (L)-based cell (3.5%). This result is due to the different molecular orientation caused by the higher molecular weight. Grazing incidence wide-angle X-ray scattering (GIWAXS) analyses revealed that the blended film of 12OD (H)/[6,6]-phenyl-C-61-butyric acid methyl ester (PC61BM) formed a face-on orientation with a long-range ordered structure, while a low crystalline edge-on structure was observed in the blended film of 12OD (L)/PC61BM. Such high crystalline and favorable molecular orientation could promote light harvesting efficiency and hole transporting ability, resulting in high J(sc) and thus an excellent PCE. From the detailed GIWAXS analysis, the orientation change of 12OD (H) was induced by the addition of PC61BM. This result suggests that the strong aggregation ability of 12OD (H) can drive crystallization and favors active interaction with PC61BM to form a face-on orientation. In this study, the increase in molecular weight can improve not only the thin-film structure such as crystallinity and phase separation structure but also the molecular orientation in the PDT-based polymer system.

DOI： 10.1021/acs.macromol.7b00778

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Synthesis of Benzoisoselenazolone Derivatives by Nickel-Catalyzed Dehydrogenative Direct Selenation of C(sp(2))-H Bonds with Elemental Selenium in Air 査読

Masayuki Iwasaki, Natsumi Miki, Yuta Tsuchiya, Kiyohiko Nakajima, Yasushi Nishihara

ORGANIC LETTERS 19 ( 5 ) 1092 - 1095 2017年3月

担当区分：最終著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER CHEMICAL SOC

Nickel-catalyzed direct selenation of benzamides bearing an 8-quinolyl auxiliary with elemental selenium provides benzoisoselenazolones in good yield via carbon selenium and nitrogen-selenium bond formation under aerobic conditions. In addition to aryl C-H bonds, the method can also be applied to alkenyl C-H bonds, constructing an isoselenazolone skeleton. Simple mechanistic analysis shows that the reaction proceeds through a rate-determining C-H bond cleavage. The obtained benzoisoselenazolones are transformed into various organoselenium compounds and utilized as the catalyst for bromolactonization of alkenoic acids.

DOI： 10.1021/acs.orglett.7b00116

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