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Studies of Biologically Relevant Oxidation Processes with Singlet Oxygen

单线态氧的生物学相关氧化过程的研究

基本信息

批准号：
8109942
负责人：
MATTHIAS SELKE
金额：
$ 17.88万
依托单位：
CALIFORNIA STATE UNIVERSITY LOS ANGELES
依托单位国家：
美国
项目类别：
财政年份：
2008
资助国家：
美国
起止时间：
2008-08-01 至 2013-07-31
项目状态：
已结题

项目摘要

DESCRIPTION (provided by applicant): The chemistry of singlet oxygen with metal-bound thiolates, arylphosphines and some phenolic antioxidants 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, especially concerning the reactivity of peroxidic intermediates formed during oxidations initiated by so-called "reactive oxygen species" and (ii) to explore chemistry of singlet oxygen - a highly reactive oxygen species - with seleced biomolecules. Reactive intermediates in oxygen chemistry are often difficult to detect because they themselves are powerful oxidants. We are 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 other unusual peroxides. We are planning to study the chemistry of phosphadioxiranes, as an example of a highly reactive heteroatom peroxide. This species acts as an "oxene"-like oxygen atom transfer agent, and undergoes several other reactions discovered by us. We will study the factors that govern the reactivity of this highly unstable reactive intermediate. Finally, we will study the chemistry of the powerful phenolic antioxidant trans-resveratrol with singlet oxygen. The chemistry of resveratrol with free radicals is well known. However, its chemistry with singlet oxygen has not been explored, yet knowing whether or not resveratrol forms highly reactive peroxidic species with singlet oxygen is essential to evaluate its health benefits. We will determine the products and any reactive intermediates formed during the interaction between resveratrol and singlet oxygen.

描述（由申请人提供）：将探索单线态氧与金属结合的硫醇盐、芳基膦和一些酚类抗氧化剂的化学反应。这方面的研究还很少。其基本目标有两个：（i）解决氧化化学中的一些基本机制问题，特别是关于由所谓的“活性氧”引发的氧化过程中形成的过氧化中间体的反应性；（ii）探索单线态氧（一种高活性氧）与选定生物分子的化学反应。氧化学中的反应中间体通常难以检测，因为它们本身就是强氧化剂。我们正在使用单线态双氧来观察并可能分离这些物种，并在适用的情况下研究它们作为氧化剂的潜力。具体来说，将研究单线态氧与金属硫醇盐，特别是S-结合半胱氨酸的化学反应。我们将探索多种反应途径，例如次磺酸盐的形成、亚磺酸盐、C-S键断裂或金属中心的氧化加成。我们将确定决定此类硫醇盐对氧化损伤的敏感性的因素（金属的氧化态、质子与非质子环境、空间）。硫醇盐配体通常充当多核配合物中的桥梁，并且还将探索此类物质与单线态氧的化学反应。配体氧化和金属中心分子氧的反应都是此类系统中可能的反应途径。我们将解决第一个金属的氧化如何影响第二个金属中心的反应性的基本问题。我们还将研究其他不寻常的过氧化物的化学性质。我们计划研究磷二环氧乙烷的化学性质，作为高反应性杂原子过氧化物的一个例子。该物质充当类似“oxene”的氧原子转移剂，并经历我们发现的其他几种反应。我们将研究控制这种高度不稳定的反应中间体的反应性的因素。最后，我们将研究强大的酚类抗氧化剂反式白藜芦醇与单线态氧的化学反应。白藜芦醇与自由基的化学反应是众所周知的。然而，其与单线态氧的化学反应尚未被探索，但了解白藜芦醇是否与单线态氧形成高反应性过氧化物物种对于评估其健康益处至关重要。我们将确定白藜芦醇和单线态氧相互作用期间形成的产物和任何反应中间体。