Water Oxidation in Synthetic heme Oxidase Models

合成血红素氧化酶模型中的水氧化

• 批准号: 7633226
• 负责人: ALEXANDER T RADOSEVICH
• 金额: $ 4.72万
• 依托单位: MASSACHUSETTS INSTITUTE OF TECHNOLOGY
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-11-16 至 2010-11-15
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7633226
• 关键词: Address; Adoption; Architecture; Biochemistry; Breathing; Carbon; Chemicals; Chronic; Cleaved cell; Complex; Confidential Information; Coupled; Cytochrome P450; Dependence; Development; Electrons; Elements; Energy-Generating Resources; Environment; Environmental Pollution; Enzymes; Evaluation; Event; Exposure to; Fossil Fuels; Funding; Generations; Goals; Health; Heme; Human; Hydrogen; Hydrogen Bonding; Investigation; Iron; Language; Life; Ligands; Metabolic; Metalloporphyrins; Metals; Methods; Microscopic; Mission; Mixed Function Oxygenases; Modeling; Modification; Molecular; Mononuclear; Nature; Organism; Oxidants; Oxidases; Oxidation-Reduction; Oxygen; Photosynthesis; Plants; Pollution; Positioning Attribute; Process; Protons; Public Health; Reaction; Research; Research Design; Risk; Role; Scheme; Solar Energy; Staging; Structure; Techniques; Touch sensation; Water; base; biological systems; catalyst; chemical bond; corrole; design; improved; metal complex; metalloenzyme; oxidation; photosystem II; planetary Atmosphere; success; urban area

DESCRIPTION (provided by applicant): The proposed research describes the development of a mononuclear iron catalyst for the oxidation of water to molecular oxygen. Inspiration for elements of catalyst design are drawn from enzymes for which molecular oxygen is a natural substrate. In particular, it is hypothesized that initial O-O bond formation should be possible by nucleophilic attack of an activated water molecule on a highly oxidizing and electrophilic oxometal unit. Two factors are critical for realizing this reaction: 1) generation of a sufficiently reactive electron-deficient oxometal unit, and 2) management of protons during the key O-O bond forming event. The proposed catalyst addresses these concerns by suggesting that an appropriately ligated Fe(V)- oxo unit will be energetically disposed to undergo O-O bond formation with water. The reactivity of the Fe (V)-oxo species will be tuned using a new class of corrole-derived 'hangman' ligands, which position hydrogen bonding functionality above the plane of a tetrapyrrolic equatorial environment. The synthesized structures will be evaluated in two stages for initial Fe(V)-oxo generation and then subsequent O-O bond formation and O2 liberation. In this regard, the proposed mechanism resembles the microscopic reverse of cytochrome P450 function, where O2 is cleaved to furnish water and a high-valent iron-oxo intermediate. As such, it is expected that the proposed research will offer perspectives on the mechanism and energetic requirements of the cytochrome P450 monooxygenases. Additionally, long-term success of the proposed research represents an introduction to the possibility of converting water to molecular oxygen and hydrogen for use as fuels. Such a scheme would help reduce global dependence on fossil fuel combustion which would dramatically improve public health, especially in urban areas, by reducing environmental pollution. The risks associated with chronic exposure to pollution from fossil fuel combustion are a major and increasing public health concern. Consequently, the adoption of new non-carbon based energy sources is expected to directly improve human health, especially in urban areas. This proposal describes the design and evaluation of a water oxidation catalyst that could be used as part of a scheme to produce hydrogen, a non-polluting fuel.

描述（由申请人提供）：拟定的研究描述了用于将水氧化为分子氧的单核铁催化剂的开发。催化剂设计元素的灵感来自于以分子氧为天然底物的酶。特别是，假设初始O-O键的形成应该是可能的，通过活化水分子对高氧化性和亲电金属氧单元的亲核攻击。两个因素对于实现该反应是关键的：1）产生足够反应性的缺电子氧代金属单元，以及2）在关键的O-O键形成事件期间对质子的管理。所提出的催化剂通过建议适当连接的Fe（V）-氧代单元将被能量地布置以与水进行O-O键形成来解决这些问题。的Fe（V）-氧物种的反应性将使用一类新的腐蚀衍生的“刽子手”配体，其位置氢键功能的平面上方的tetraphyrrolic赤道环境进行调整。合成的结构将在两个阶段进行评估，最初的Fe（V）-氧代生成，然后随后的O-O键形成和O2释放。在这方面，所提出的机制类似于细胞色素P450功能的微观逆转，其中O2被裂解以提供水和高价铁-氧代中间体。因此，预计拟议的研究将提供细胞色素P450单加氧酶的机制和能量需求的观点。此外，拟议研究的长期成功代表了将水转化为分子氧和氢用作燃料的可能性。这种计划将有助于减少全球对化石燃料燃烧的依赖，从而通过减少环境污染，大大改善公共卫生，特别是城市地区的公共卫生。与长期接触化石燃料燃烧产生的污染有关的风险是一个重大的和日益严重的公共健康问题。因此，采用新的非碳基能源预计将直接改善人类健康，特别是在城市地区。该提案描述了水氧化催化剂的设计和评估，该催化剂可用作生产氢（一种无污染燃料）的方案的一部分。