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Matsumoto T, Yamamoto R, Wakizaka M, Nakada A, Chang HC. Molecular Insights into the Ligand-Based Six-Proton- and Six-Electron-Transfer Processes Between Tris-ortho-Phenylenediamines and Tris-ortho-Benzoquinodiimines. Chemistry 2020; 26:9609-9619. [PMID: 32483884 DOI: 10.1002/chem.202001873] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Indexed: 11/10/2022]
Abstract
The global demand for energy and the concerns over climate issues renders the development of alternative renewable energy sources such as hydrogen (H2 ) important. A high-spin (hs) FeII complex with o-phenylenediamine (opda) ligands, [FeII (opda)3 ]2+ (hs-[6R]2+ ), was reported showing photochemical H2 evolution. In addition, a low-spin (ls) [FeII (bqdi)3 ]2+ (bqdi: o-benzoquinodiimine) (ls-[0R]2+ ) formation by O2 oxidation of hs-[6R]2+ , accompanied by ligand-based six-proton and six-electron transfer, revealed the potential of the complex with redox-active ligands as a novel multiple-proton and -electron storage material, albeit that the mechanism has not yet been understood. This paper reports that the oxidized ls-[0R][PF6 ]2 can be reduced by hydrazine giving ls-[FeII (opda)(bqdi)2 ][PF6 ]2 (ls-[2R][PF6 ]2 ) and ls-[FeII (opda)2 (bqdi)][PF6 ]2 (ls-[4R][PF6 ]2 ) with localized ligand-based proton-coupled mixed-valence (LPMV) states. The first isolation and characterization of the key intermediates with LPMV states offer unprecedented molecular insights into the design of photoresponsive molecule-based hydrogen-storage materials.
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Affiliation(s)
- Takeshi Matsumoto
- Department of Applied Chemistry, Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo 112-8551, Japan.,Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency (JST), 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012, Japan
| | - Risa Yamamoto
- Department of Applied Chemistry, Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo 112-8551, Japan
| | - Masanori Wakizaka
- Department of Applied Chemistry, Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo 112-8551, Japan
| | - Akinobu Nakada
- Department of Applied Chemistry, Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo 112-8551, Japan
| | - Ho-Chol Chang
- Department of Applied Chemistry, Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo 112-8551, Japan
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