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）：拟议的研究描述了将水氧化为分子氧的单核铁催化剂的发展。催化剂设计元素的灵感是从分子氧为天然底物的酶中汲取的。特别是，假设通过激活的水分子在高度氧化和亲电的氧图单位上的亲核发作来形成初始O-O键的形成。两个因素对于意识到这一反应至关重要：1）产生足够反应性电子缺陷的Oxometal单位，以及2）在关键的O-O键形成事件中对质子进行管理。提出的催化剂通过建议适当的连接Fe（V） - Oxo单位能够在能量上消除以与水进行O-O键形成，以解决这些问题。 Fe（V） - 氧化物物种的反应性将使用新的孔罗尔衍生的“ hang鼠”配体调整，这些配体将氢键功能定位在四吡咯赤道环境的平面上方。合成的结构将在两个阶段进行初始Fe（V）-Oxo生成，然后在随后的O-O键形成和O2释放中进行评估。在这方面，提出的机制类似于细胞色素P450功能的微观反向，其中O2被切割成提供水和高价值的铁氧中间体。因此，预计拟议的研究将提供有关细胞色素P450单加速酶的机制和能量要求的观点。此外，提出的研究的长期成功代表了将水转换为分子氧和氢以用作燃料的可能性。这样的计划将有助于减少全球对化石燃料燃烧的依赖，这将通过减少环境污染来大大改善公共卫生，尤其是在城市地区。与化石燃料燃烧污染的长期暴露有关的风险是一个重大的公共卫生问题。因此，采用新的非碳能源有望直接改善人类健康，尤其是在城市地区。该提案描述了可以用作生产氢（一种非冲洗燃料）的水氧化催化剂的设计和评估。