O2 AS TOOL TO STUDY METAL CATALYZED OXYGENATION REACTIONS

许多金属配合物能够与单线态氧干净地反应，生成新的金属-过氧配合物。该方法为制备金属-双氧配合物提供了一种新方法，从而产生了模拟重要酶的新模型系统，并对氧原子转移到各种底物的机制有了新的认识。过渡金属配合物与单线态氧的反应可以在很低的温度下进行。因此，热力学上非常不稳定的金属-二氧配合物，其存在以前仅限于推测的领域，可以合成，直接观察，并可以研究它们的反应性。同时，对金属中单线态氧的氧化加成范围进行了研究。到目前为止，还没有关于早期过渡金属的此类反应的报道。我们将尝试从早期过渡金属与单线态氧衍生出几种具有生物学意义的过氧配合物。其他子项目将探索金属配位硫代酸盐氧化的机理特征。本文将探讨由氧原子转移到硫原子的金属氧化是否是一个可行的反应途径。另一个子项目涉及铜配合物的内过氧化物配位的合成，作为铜酶槲皮素酶的模型。单线态氧与双核配合物的不同反应也将被考察。总之，各种不同的子项目反映了不同的领域，在这些领域中，利用单线态氧作为一种机械工具可能会导致重要的机械见解。

Many metal complexes are able to react cleanly with singlet oxygen to make new metal-peroxo complexes. This methodology suggests a new approach toward the preparation of metal-dioxygen complexes, leading to new model systems that mimic important enzymes and to new insights into the mechanism of oxygen atom transfer to a variety of substrates. Reactions of transition metal complexes with singlet oxygen can be carried out at very low temperatures. Thus, thermodynamically very unstable metal-dioxygen complexes whose existence has previously been limited to the realm of speculation can be synthesized, directly observed, and their reactivities can be studied. At the same time, the scope of oxidative addition of singlet oxygen to metals will be studied. Thus far, no such reactions have been reported for early transition metals. We will attempt to prepare several biologically relevant peroxo complexes derived from early transition metals with singlet oxygen. Other subprojects will probe the mechanistic features of the oxidation of metal-coordinated thiolates. It will be examined whether or not oxidation of the metal followed by oxygen atom transfer to the sulfur atom is a viable reaction pathway. Another subproject involves the synthesis of an endoperoxide coordinate to a copper complex as a model for the copper enzyme quercetinase. Different reactions of singlet oxygen with dinuclear complexes will also be examined. In summary, the various rather diverse subprojects reflect the diverse areas in which the utilization of singlet oxygen as a mechanistic tool may lead to important mechanistic insights.