Development of Metal-Polypyridylamine Complexes for Base-Driven Valence Tautomerism

• Project/Area Number: 17K14456
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Inorganic chemistry
• Research Institution: University of Tsukuba
• Principal Investigator: Kotani Hiroaki 筑波大学, 数理物質系, 助教 (10610743)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Project Status: Completed (Fiscal Year 2019)
• Budget Amount: ¥4,550,000 (Direct Cost: ¥3,500,000、Indirect Cost: ¥1,050,000); Fiscal Year 2019: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000); Fiscal Year 2018: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000); Fiscal Year 2017: ¥2,730,000 (Direct Cost: ¥2,100,000、Indirect Cost: ¥630,000)
• Keywords: 酸化還元活性 / 脱プロトン化 / 分子内電子移動 / コバルト錯体 / 脱プロトン / 配位子ラジカル / 速度論解析 / レドックスノンイノセント / 金属錯体 / 原子価互変異性

Outline of Final Research Achievements

we prepared Co(III)-TPA complexes having diketonato ligands to investigate the deprotonation of Co(III)-TPA complexes and the intramolecular electron transfer between the deprotonated TPA ligand and a redox-active Co(III) ion to form a Co(II)-TPA radical complex. The formation of the Co(II)-TPA radical complex was confirmed by the radical coupling reaction with an N-oxyl radical (TEMPO) by spectroscopic measurements and ESI-MS spectrometry.

Academic Significance and Societal Importance of the Research Achievements

外部刺激の１つである酸塩基反応（pH変化）によるコバルト錯体の分子内電子移動の制御に成功した。つまり、金属中心であるCo(III)イオンのルイス酸性により脱プロトン化した支持配位子が生成し、その脱プロトン化配位子から酸化還元活性なCo(III)イオンへの分子内電子移動によりCo(II)配位子ラジカル錯体が生成する。こうした酸塩基反応をトリガーとした分子内電子移動の制御により、多彩な電子状態の発現が可能となる。

Research Products

• [Journal Article] Dioxygen/Hydrogen Peroxide Interconversion Using Redox Couples of Saddle-Distorted Porphyrins and Isophlorins (2019)
  • Author(s): W. Suzuki, H. Kotani, T. Ishizuka, T. Kojima
  • Journal Title: Journal of the American Chemical Society Volume: 141 Issue: 14 Pages: 5987-5994
  • DOI: 10.1021/jacs.9b01038
  • Peer Reviewed
• [Journal Article] Mechanistic Insight into Dioxygen Evolution from Diastereomeric μ-Peroxo Dinuclear Co(III) Complexes Based on Stoichiometric Electron-Transfer Oxidation (2019)
  • Author(s): H. Kotani, D. Hong, K. Satonaka, T. Ishizuka, T. Kojima
  • Journal Title: Inorganic Chemistry Volume: 58 Issue: 6 Pages: 3673-3682
  • DOI: 10.1021/acs.inorgchem.8b03245
  • Peer Reviewed
• [Journal Article] Catalytic Oxidative Cracking of Benzene Rings in Water (2019)
  • Author(s): Y. Shimoyama, T. Ishizuka, H. Kotani, T. Kojima
  • Journal Title: ACS Catalysis Volume: 9 Issue: 1 Pages: 671-678
  • DOI: 10.1021/acscatal.8b04004
  • Peer Reviewed
• [Journal Article] Importance of the Reactant-State Potentials of Chromium(V)?Oxo Complexes to Determine the Reactivity in Hydrogen-Atom Transfer Reactions (2018)
  • Author(s): Kotani Hiroaki、Kaida Suzue、Ishizuka Tomoya、Mieda Kaoru、Sakaguchi Miyuki、Ogura Takashi、Shiota Yoshihito、Yoshizawa Kazunari、Kojima Takahiko
  • Journal Title: Inorganic Chemistry Volume: 57 Issue: 21 Pages: 13929-13936
  • DOI: 10.1021/acs.inorgchem.8b02453
  • Peer Reviewed
• [Journal Article] Formation and Isolation of a Four-Electron-Reduced Porphyrin Derivative by Reduction of a Stable 20π Isophlorin (2018)
  • Author(s): 4.Wataru Suzuki, Hiroaki Kotani, Tomoya Ishizuka, Yoshihito Shiota, Kazunari Yoshiza, Takahiko Kojima
  • Journal Title: Angeandte Chemie International Edition Volume: 57 Issue: 7 Pages: 1973-1977
  • DOI: 10.1002/anie.201711058
  • NAID: 120007134423
  • Peer Reviewed
• [Journal Article] Visible-Light-Driven Photocatalytic CO2 Reduction by a Ni(II) Complex Bearing a Bioinspired Tetradentate Ligand for Selective CO Production (2017)
  • Author(s): Hong, Dachao; Tsukakoshi, Yuto; Kotani, Hiroaki; Ishizuka, Tomoya; Kojima, Takahiko
  • Journal Title: JOURNAL OF THE AMERICAN CHEMICAL SOCIETY Volume: 139 Issue: 19 Pages: 6538-6541
  • DOI: 10.1021/jacs.7b01956
  • Peer Reviewed / Acknowledgement Compliant
• [Journal Article] Formation of supramolecular hetero-triads by controlling the hydrogen bonding of conjugate bases with a diprotonated porphyrin based on electrostatic interaction (2017)
  • Author(s): Suzuki Wataru、Kotani Hiroaki、Ishizuka Tomoya、Shiota Yoshihito、Yoshizawa Kazunari、Kojima Takahiko
  • Journal Title: Chem. Commun. Volume: 53 Issue: 47 Pages: 6359-6362
  • DOI: 10.1039/c7cc03635c
  • NAID: 120007128973
  • Peer Reviewed
• [Presentation] Redox Noninnocent Behavior of Tris(2-pyridylmethyl)amine Bound to Lewis Acidic Metal Ions Induced by C-H Deprotonation (2018)
  • Author(s): Hiroaki Kotani
  • Organizer: 生物無機化学国際シンポジウム2018
  • Int'l Joint Research / Invited
• [Presentation] サドル型ポルフィリンを触媒とした触媒的酸素還元反応 (2018)
  • Author(s): ○鈴木航・小谷弘明・石塚智也・小島隆彦
  • Organizer: 第29回基礎有機化学討論会
• [Presentation] ルテニウム(IV)オキソ錯体の電子移動特性に基づく反応性評価 (2018)
  • Author(s): ○下村 日夏, 小谷 弘明, 石塚 智也, 小島 隆彦
  • Organizer: 第51回酸化反応討論会
• [Presentation] 配位子の脱プロトン化によって誘起されるコバルト錯体の原子価互変異性とその制御 (2017)
  • Author(s): 大城綾、小谷弘明、石塚智也、小島隆彦
  • Organizer: 錯体化学会第６７回討論会
• [Presentation] 酸化還元活性な配位子を有する鉄錯体の高酸化状態における電子構造 (2017)
  • Author(s): 西部貴久、荻島郁弥、小谷弘明、 石塚智也、岡島敏浩、野澤俊介、塩田淑仁、吉澤一成、小島隆彦
  • Organizer: 錯体化学会第６７回討論会
• [Presentation] Photocatalytic CO2 Reduction Catalyzed by First-Row Transition-Metal Complexes Bearing an S2N2-Type Tetradentate Ligand (2017)
  • Author(s): Yuto TSUKAKOSHI,Dachao HONG,Tomoya ISHIZUKA,Hiroaki KOTANI,Takahiko KOJIMA
  • Organizer: 錯体化学会第６７回討論会
• [Presentation] サドル型ドデカフェニルイソフロリンの生成とその変換反応 (2017)
  • Author(s): 鈴木航、小谷弘明、石塚智也、塩田淑仁、吉澤一成、小島隆彦
  • Organizer: 第28回基礎有機化学討論会