Molecular Conversion Using One-Step Multi-electron Transfer Complex

钒（salen）多核配合物作为电子介质，催化氧的多电子电驱。本研究的目的是通过调节氧化还原电位，使其接近于使用各种配体进行氧的4电子还原的热力学势值，利用这些配合物作为电子介质，建立分子氧的多电子还原体系。它还旨在阐明利用这些配合物作为有机底物的氧化系统的新的分子转化系统。第一年制备了具有惰性配体的钒配合物，并测定了氧化还原电位。并制备了相应的双核配合物。这些配合物的x射线研究揭示了这些配合物中氧结合位点的结构。通过近红外光谱测定了配合物的氧化还原状态。对催化剂的氧合动力学分析表明，该催化剂中存在mu-二氧基中间体。第二年，选定的钒配合物作为电子介质，并对氧的还原进行了研究。通过旋转环盘伏安法得到的Koutecky-Levich图揭示了四电子过程和水的产生。确定催化剂的周转数大于10。结果表明，建立了氧的选择性四电子还原体系。

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.