Singlet Oxygen with Metal Thiolates and Arylphosphines

将探索单线态氧与金属有机化合物和芳基膦的化学。这一领域的研究成果很少。其基本目标有两个：(I)解决氧化化学中的一些基本机理问题；(Ii)从最无害的氧化剂，即氧气中寻找新的氧化剂。氧化学中的活性中间体通常很难检测到，因为它们本身就是强大的氧化剂。我们正在努力寻找新的方法(使用单线态氧)来观察和可能分离这些物种，并在适用的情况下，研究它们作为氧化剂的潜力。 具体地说，将研究单线态氧与金属硫酸盐的化学，特别是S结合的半胱氨酸。我们将探索不同的反应途径，如亚硫酸盐的形成，亚硫酸盐，C-S键断裂或金属中心的氧化加成。我们将确定决定这些硫酸盐对氧化损伤的敏感性的因素(金属的氧化状态、质子态与非质子态环境、立体结构)。硫代配体经常作为多核络合物的桥梁，也将探索此类物种与单线态氧的化学作用。在这类体系中，配体氧化和金属中心的氧反应都是可能的反应途径。我们将讨论第一个金属的氧化如何影响第二个金属中心的反应性这一根本问题。我们还将研究单重态氧与芳基膦的化学。尽管三价磷与氧的亲和力是众所周知的，但以前还没有关于芳基膦与单线态氧的化学作用的研究，也没有直接观察到单线态氧氧化磷化氢的中间产物。我们正计划研究这些中间体，并将它们用作一类新型的氧原子转移剂。

The chemistry of singlet oxygen with organometallic compounds and arylphosphines will be explored. Very little research has been accomplished in this area. The basic aims are twofold: (i) To solve a number of fundamental mechanistic questions in oxidation chemistry, and (ii) to find new oxidants derived from the most benign oxidant, i.e. dioxygen. Reactive intermediates in oxygen chemistry are often difficult to detect because they themselves are powerful oxidants. We are trying to find new methods (using singlet dioxygen) to observe and possibly isolate such species and, where applicable, to investigate their potential as oxidants. Specifically, the chemistry of singlet oxygen with metal thiolates, especially S-bound cysteine will be investigated. We will explore the diverse reaction pathways such as formation of sulfenate, sulfinate, C-S bond cleavage or oxidative addition at the metal center. We will determine factors (oxidation state of metal, protic vs. aprotic environment, sterics) that determine the susceptibility of such thiolates toward oxidative damage. Thiolate ligands often serve as bridges in multinuclear complexes, and the chemistry of such species with singlet oxygen will be explored as well. Both ligand oxidation and reaction of dioxygen at the metal center are possible reactive pathways in such systems. We will address the fundamental question of how oxidation at the first metal affects reactivity at the second metal center. We will also investigate the chemistry of singlet oxygen with arylphosphines. Despite the well-known affinity of trivalent phosphorous for oxygen, there have been no previous studies of the chemistry of arylphosphines with singlet oxygen, and intermediates in the oxidation of phosphines by singlet oxygen have never been directly observed. We are planning to study these intermediates and use them as a novel "oxene"-like class of oxygen atom transfer agents.