Molecular Conversion Using One-Step Multi-electron Transfer Complex

钒(Salen)多核配合物作为电子媒介体，实现了氧的催化多电子电还原。通过将氧化还原电势调节到接近氧的四电子还原热力学电势的值，本研究的目的是利用这些配合物作为电子介体，建立分子氧的多电子还原体系。首次制备了含惰性配体的钒配合物，并测定了其氧化还原电位。此外，还制备了相应的双核配合物。对这些络合物的X射线研究揭示了这些络合物中氧结合部位的结构。通过近红外光谱确定了配合物的氧化还原状态。对催化剂的氧化动力学分析表明，催化剂中存在二氧钼中间体。第二年，选择的钒配合物作为电子媒介，考察了氧的还原情况。用旋转环-盘伏安法得到的Koutecky-Levich图揭示了4电子过程和水的产生。催化剂的翻转数大于10，从而建立了氧的选择性4电子还原体系。

Vanadyl (salen) multi-nuclear complexes act as electron mediators to allow catalytic multi-electron electroeduction of oxygen. By adjusting redox potentials to the value close to the thermodynamic potential for the 4-electron reduction of oxygen using a variety of ligands, the objective of the present study is to establish multi-electron reduction systems of molecular oxygen by the use of these complexes as electron mediators. It is also intended to elucidate novel molecular conversion systems by the use of these complexes as oxidation systems for organic substrates.It the first year, vanadium complexes with inert ligands were prepared and the redox potentials were determined. Also, the corresponding dinuclear complexes were prepared. X-ray studies of these complexes revealed the structure of the oxygen-binding sites in these complexes. By near-infrared spectrum, the redox state of the complexes were determined. Kinetic analysis for the oxygenation of the catalyst revealed the presence of mu-dioxo intermediate.In the second year, the selected vanadium complexes were used as electron mediators, and the reduction of oxygen was examined. Koutecky-Levich Plots obtained by the rotating ring-disk voltammetry revealed the 4-electron process and the production of water. The turn-over number of the catalyst was determined to exceed 10. It was concluded that selective 4-electron reduction system of oxygen was established.