Singlet Oxygen with Metal Thiolates and Arylphosphines

单线态氧与有机金属化合物和芳基膦的化学将被探索。这方面的研究很少。基本目标有两个方面：（i）解决氧化化学中的一些基本机理问题，（ii）从最温和的氧化剂，即分子氧中找到新的氧化剂。氧化学中的活性中间体通常很难检测，因为它们本身就是强氧化剂。我们正试图找到新的方法（使用单线态分子氧）来观察和分离这些物种，并在适用的情况下，研究它们作为氧化剂的潜力。 具体而言，单线态氧与金属硫醇盐，特别是S-结合半胱氨酸的化学将被研究。我们将探讨不同的反应途径，如形成亚磺酸盐，亚磺酸盐，C-S键断裂或在金属中心的氧化加成。我们将确定的因素（金属的氧化态，质子与非质子环境，立体），确定这种硫醇盐对氧化损伤的敏感性。硫醇配体通常作为多核配合物中的桥梁，这些物种与单线态氧的化学也将被探索。配体氧化和分子氧在金属中心的反应是这类体系中可能的反应途径。我们将解决的基本问题，如何在第一金属氧化影响反应性的第二金属中心。我们也将研究单线态氧与芳基膦的化学反应。尽管三价磷对氧的亲和力是众所周知的，但以前没有研究过芳基膦与单线态氧的化学反应，也从未直接观察到单线态氧氧化膦的中间体。我们正计划研究这些中间体，并将其用作新型的“oxene”类氧原子转移剂。

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.