Sulfur oxidation reaction by cobalt complex using dioxygen activation on metal

2023 Fiscal Year Final Research Report

• Project/Area Number: 17K05822
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Inorganic chemistry
• Research Institution: Ibaraki National College of Technology
• Principal Investigator: Komatsuzaki Hidehito 茨城工業高等専門学校, 国際創造工学科, 教授 (00280347)
• Project Period (FY): 2017-04-01 – 2024-03-31
• Keywords: コバルト錯体 / トリスピラゾリルボレート / 酸素活性化 / 硫黄酸化 / チオラト錯体

Outline of Final Research Achievements

In this study, we synthesized targeted complexes of various thiolato ligands attached to the cobalt(II) center using hydrotris(pyrazolyl)borate ligands and investigated their sulfur oxidation reactions. The target complexes were synthesized by the reaction of a cobalt (II) nitrato complex with the corresponding metal thiolate. The obtained complexes were identified by various spectral measurements and X-ray structural analyses. When oxygen reacts with an acetonitrile solution of an o-aminothiophenolato cobalt(II) complex, its sulfur atom is oxidized and a sulfanato-bridged dinuclear cobalt complex is formed. In p-substituted thiophenolato cobalt(II) complexes, sulfur oxidation was also found to proceed upon reaction with oxygen. These reactions are speculated to occur after the activation of the dioxygen on cobalt(II), followed by sulfur atom oxidation.

Free Research Field

錯体化学

Academic Significance and Societal Importance of the Research Achievements

近年、システインジオキシゲナーゼの硫黄酸化酵素の生物学的研究が進められてきたが、そのモデル錯体の報告は少なく、反応機構や活性種などの報告は少なかった。これまでに鉄(II)モデル錯体やそれを他の金属で置換した金属置換錯体が数例報告されてきたが、酵素反応機構の解明や活性種の特定に繋がる知見には乏しかった。本研究では、種々コバルト(II)チオラト錯体を合成し、コバルト上で酸素活性化を行い、チオラト硫黄原子酸化が進行することを報告することができた。また、硫黄酸化を触媒する酵素反応の理解の一助になると考えられる。