Design of Electron Transfer Catalysts in Electrolysis System

点击翻译按钮获取中文摘要

This joint project was concerned in (1) design and control of novel electron-transfer systems and (2) investigation of the structure of the unstable active species and of the mechanism of electron transfer by electrochemical analysis. The former was mainly done in Japan, and the latter in abroad. The major effort was devoted on development of new electrochemical reactions using metal complex redox systems, containing Pd, Ni, Co, Os, and Mn, and organic redox molecules, such as Ar_3N and N-oxyls.The results are summarized as follows :(1) Electro-reductive generation and reaction of coordinately unsaturated Pd complex : The electro-generated active species are found to have unique properties and reactivities, which could not have been seen in ordinal homogeneous metal-catalyzed reaction. From this study, new electro-reduction systems promoting cross-coupling of aryl halides, umpolung of acylpalladium species, so on, have been developed.(2) Electrochemical asymmetric induction in oxidation of olefins using chiral transition metal complexes : Asymmetric dihydroxylation and epoxidation by recycling co-oxidant in electrolysis media have been successfully achieved. The chemical and optical yields of the products, diols and epoxides, are higher than those from chemical oxidation.(3) Construction of novel electron-transfer system using Ar_3N/Ar_3N^+ and N-oxyl redox : Successful applications of Wacker oxidation and alcohol oxidation were attained by use of cobination of the organic redox and metal redox. Design and synthesis of polyradicals connected by conjugated pi-electron systems were also carried out. It was revealed that spin-spin interaction in biradicals occurred through the conjugated pi-electron system. It is expected to regulate the spin arrangement to have the ferromagnetic properties.Since the stuffs in Japan and abroad have done their research in their specialities under a close connection, the project proceeded smoothly and outstanding results were obtained.