O2 AS TOOL TO STUDY METAL CATALYZED OXYGENATION REACTIONS

许多金属络合物能够与单线态氧清洁地反应生成新的金属-过氧络合物。这一方法学为制备金属-氧配合物提供了一种新的方法，导致了模拟重要酶的新的模型系统，并对氧原子转移到各种底物的机制有了新的见解。过渡金属络合物与单线态氧的反应可以在很低的温度下进行。因此，可以合成热力学上非常不稳定的金属-二氧化氧络合物，这些络合物的存在以前被限制在推测的领域，可以直接观察到，并且可以研究它们的反应性。同时，对单线态氧在金属中氧化加成的范围进行了研究。到目前为止，还没有关于早期过渡金属发生这样的反应的报道。我们将尝试从早期过渡金属与单线态氧制备几种生物相关的过氧络合物。其他子项目将探索金属配位硫酸盐氧化的机理特征。将研究金属氧化，然后氧原子转移到硫原子是否是一种可行的反应途径。另一个子项目涉及合成铜络合物的内过氧化配位物，作为铜酶quercetinase的模型。还将考察单线态氧与双核络合物的不同反应。总而言之，各种不同的次级项目反映了单线态氧作为机械工具的利用可能导致重要的机械洞察的不同领域。

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.