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Chemistry of Coordinatively Unsaturated Transition Metal-Dioxygen Complex

配位不饱和过渡金属-双氧配合物的化学

基本信息

批准号：
04650787
负责人：
NISHINAGA Akira
金额：
$ 1.28万
依托单位：
Osaka Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1992
资助国家：
日本
起止时间：
1992 至 1993
项目状态：
已结题

项目摘要

Electronically and sterically designed four coordinate cobalt (II) Schiff base complexes and their dioxygen adducts formed at low temperature were prepared. Chemical behavior of these coordinatively unsaturated superoxocobalt (III) complexes [CoIII(SB)(O2)] were investigated to find the following results.(1) CoIII (SB) (O2) as an oxidizing agent was found to be very low : normally oxidizable phenolic compounds as wsell as triphenylphosphin were not oxidized with any coordinatively unsaturated CoII (SB) (O2). However, in the presence of an acid or acyl chloride, triphenylphosophin was oxidized to triphenylphosphin oxide, where hydrogen peroxide or diacylperoxide formed in situ was the oxidizing agent.(2) CoIII (SB) (O2) was found ito reduce o-quinons to igve semiquinonatocobalt (III) complex quantitatively. On the other hand, no reaction took place with p-quinons. These results suggest that the electron density of the coordinated superoxo species in coordinatively unsaturated complex is poor compaired to that in coordinatively sturated one.(3) Radical reactivity of CoIII (SB) (O2) : no reaction with phenoxy radicals were found contrary to the case with coordinatively saturated superoxocobalt (III) complex, which can couple with phenoxy radicals at lower temperature. The less radical reactivity of CoIII (SB) (O2) may be attributed to its electronic stae having metal characteristics.(4) Anionic nature of CoIII (SB) (O2) was found in the reaction wiht benzoyl chloride to give dibenzoyl peroxide, of which formation is considered to recombination of two molecules of benzoylperoxy radical.

合成了四配位钴（II）席夫碱配合物及其低温双氧加合物。研究了这些配位不饱和超氧代钴（III）配合物[CoIII（SB）（O2）]的化学行为，发现以下结果。(1)发现作为氧化剂的Co III（SB）（O2）非常低：通常可氧化的酚类化合物如三苯基膦不被任何配位不饱和Co II（SB）（O2）氧化。然而，在酸或酰氯的存在下，三苯基膦被氧化成三苯基膦氧化物，其中原位形成的过氧化氢或过氧化二酰是氧化剂。(2)Co Ⅲ（SB）（O_2）能定量还原邻醌生成半醌钴（Ⅲ）配合物。另一方面，与对醌没有发生反应。这些结果表明，配位不饱和配合物中的配位超氧物种的电子密度比配位饱和配合物中的低。(3)自由基反应性的钴III（SB）（O2）：没有发现与苯氧基自由基的反应相反，与配位饱和的超氧代钴（III）配合物的情况下，它可以在较低的温度下与苯氧基自由基耦合。CoIII（SB）（O2）的自由基反应性较低可能是由于其电子态具有金属特性。(4)在与苯甲酰氯反应生成过氧化二苯甲酰的过程中，发现了CoIII（SB）（O2）的阴离子性质，认为其形成是两个过氧苯甲酰自由基分子的复合。