著者

大久保 將史

出版者

錯体化学会

雑誌

Bulletin of Japan Society of Coordination Chemistry (ISSN:18826954)

巻号頁・発行日

vol.82, pp.29-41, 2023-11-30 (Released:2023-12-26)

参考文献数

63

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A net-zero society needs integration of a large amount of renewable energy to a power grid while ensuring the quality of electricity. As the intermittent power from the renewables should be load-leveled using low-cost and high-power 1 MWh-scale stationary batteries, sodium-ion batteries that are comprised of abundant elements have attracted recent research interest. One of the most promising positive electrode materials for sodium-ion batteries is a family of Prussian blues (PB) and Prussian blue analogues (PBA), which delivers a large capacity of > 150 mAh/g at a high operating voltage of approximately 3.5 V vs. Na/Na+, meeting performance criteria for large-scale stationary batteries. However, for their commercialization, especially in Japan, further data accumulation including cycle stability, safety, and life cycle assessment is necessary. This review summarizes recent research and development of the PB and PBA electrodes for sodium-ion batteries.

著者

沈 建仁

出版者

錯体化学会

雑誌

Bulletin of Japan Society of Coordination Chemistry (ISSN:18826954)

巻号頁・発行日

vol.72, pp.3-14, 2018-11-30 (Released:2019-04-01)

参考文献数

62

被引用文献数

1 1

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Photosystem II (PSII) is a huge membrane-protein complex catalyzing light-induced electron transfer and water oxidation reactions, leading to the conversion of light energy into chemical energy and the evolution of molecular oxygen, two products indispensable for sustaining almost all life forms on the earth. This account describes the structure of PSII with the focus on that of the catalytic center for water oxidation, a Mn4CaO5-cluster embedded in the protein matrix of PSII, revealed by conventional highresolution X-ray crystallography and femtosecond X-ray free electron laser (XFEL) crystallography. Latest results on the structural changes of the Mn4CaO5-cluster during the water oxidation reaction cycle obtained by the femtosecond XFEL crystallography are also described. Based on these results as well as those obtained with other approaches, the mechanism of water oxidation and oxygen evolution is discussed. Other functions of PSII such as proton release pathways and light energy absorption and transfer are also discussed briefly.

著者

大木 靖弘

出版者

錯体化学会

雑誌

Bulletin of Japan Society of Coordination Chemistry (ISSN:18826954)

巻号頁・発行日

vol.66, pp.26-30, 2015-11-30 (Released:2016-03-04)

参考文献数

27

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Nirtogenases are a class of enzymes that catalyze the reduction of N2 to NH3 under ambient conditions in the presence of protons and electrons. The active site of the most prevalent nitrogense is called as the FeMo-cofactor, which is often designated as the M-cluster. It consists of one molybdenum, seven irons, and several sulfur atoms, and represents the most complex metal-sulfur cluster in biology. Some homologues containing vanadium or iron in place of molybdenum exist in alternative nitrogenases, while a precursor of FeMo-cofactor was also identified as an all-iron homologue. Recent crystallographic and biochemical studies on nitrogenases uncovered some important clues about the structurefunction relationship of the nitrogenase active sites, such as the precise structure of the FeMo-cofactor, unique catalytic functions of the FeMo-cofactor and its homologues, and the detailedmechanistic insights in the nitrogen fixation. Transition-metal mediated conversion of small molecules that contain triple bonds has been of interest to the community of coordination chemistry, and this contribution introduces some important progresses in the nitrogenase chemistry/biochemistry made in recent years.

著者

井頭 麻子 藤原 隆司 堀 顕子

出版者

錯体化学会

雑誌

Bulletin of Japan Society of Coordination Chemistry (ISSN:18826954)

巻号頁・発行日

no.58, pp.55-59, 2011-11

著者

桑田 繁樹

出版者

錯体化学会

雑誌

Bulletin of Japan Society of Coordination Chemistry (ISSN:18826954)

巻号頁・発行日

vol.76, pp.21-30, 2020-11-30 (Released:2021-01-05)

参考文献数

70

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Proton-responsive pincer-type ligands have been used as scaffolds to realize metal–ligand cooperative transformations. Unlike most of the ligands therein, 2,6-bis(pyrazol-3-yl)pyridines (3-bpp) ensure that two protic groups point to the remaining coordination site in the pincer plane. This article reviews the coordination chemistry of 3-bpp and related tridentate ligands with emphasis on the characteristics originating from the Brønsted acidity of the peripheral NH groups. Synthesis of 3-bpp complexes, which often associated with spontaneous deprotonation of the 3-bpp ligand and aggregation of the complex to give supramolecular structures, is first described. Deprotonation of the 3-bpp complexes along with the following reactivities is then discussed. Application of the 3-bpp complexes to catalytic reactions as well as materials exhibiting spin-crossover and fluorescence is also described. Finally, pincer-type complexes bearing protic N-heterocyclic carbene side arms are briefly mentioned as relevant molecules.

著者

杉本 直己

出版者

錯体化学会

雑誌

Bulletin of Japan Society of Coordination Chemistry (ISSN:18826954)

巻号頁・発行日

vol.65, pp.23-29, 2015-05-31 (Released:2015-09-11)

参考文献数

15

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Nucleic acids can adopt many types of noncanonical structures such as a triple helix and a quadruplex depending on the sequence and solution conditions. Recently, we developed a molecular crowding system which is the cell mimicking system to investigate thermodynamic behaviors of nucleic acids in cell. As results of our researches, the molecular crowding stabilizes the quadruplex with Hoogsteen base pairs, while it destabilizes the duplex with Watson-Crick base pairs which is the canonical structure. In this review, based on the thermodynamic results of DNA and RNA under the crowding condition, regulation of transcription and translation by the quadruplex structure of nucleic acids and its stabilizers is described. It is possible that the polymerase and ribosome bound to the template DNA and RNA, respectively, may mimic the crowded conditions in which we have shown to stabilize the quadruplex. Our results presented in this review indicate that stable noncanonical structures regulate transcription and translation. The results further our understanding of the transcription and translation processes involving the noncanonical structures and may guide the design of transcription and translation regulating drugs.

著者

西林 仁昭

出版者

錯体化学会

雑誌

Bulletin of Japan Society of Coordination Chemistry (ISSN:18826954)

巻号頁・発行日

vol.71, pp.49-55, 2018-05-31 (Released:2018-08-24)

参考文献数

22

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This paper describes our recent progress in catalytic nitrogen fixation by using transition metal-dinitrogen complexes as catalysts. Novel reaction systems for the catalytic transformation of molecular dinitrogen into ammonia and hydrazine undermild reaction conditions have been achieved by the molybdenum-, iron-, cobalt-, and vanadium-dinitrogen complexes as catalysts. New findings presented in this paper may provide a new approach to the development of economical nitrogen fixation in place of energy-consuming Haber-Bosch process.

著者

森迫 祥吾 山下 誠

出版者

錯体化学会

雑誌

Bulletin of Japan Society of Coordination Chemistry (ISSN:18826954)

巻号頁・発行日

vol.74, pp.29-45, 2019-11-30 (Released:2020-03-12)

参考文献数

100

被引用文献数

1

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In this article, recent developments regarding the organometallic chemistry of boron-containing pincer ligands, especially in which a boron coordinated to transition metal center as an anionic σ-donor ligand, are reviewed. Boron-based pincer ligands can be subdivided into three main classes; diazaborole-, carborane-, and diarylboryl-ligand. All the papers relevant to such boron-based pincer ligands that have been published since 2009 are included in this review, which also summarizes applications of transitionmetal complexes bearing such boron-containing pincer ligands in catalytic and/or bond-cleavage reactions.