The Reactivity of Vinyl Nitrene Intermediates

乙烯基氮烯中间体的反应活性

• 批准号: 0703920
• 负责人: Anna Gudmundsdottir
• 金额: --
• 依托单位: University of Cincinnati Main Campus
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-08-01 至 2011-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0703920&HistoricalAwards=false
• 关键词: Reactivity; Vinyl; Nitrene; Intermediates

With this award, the Organic and Macromolecular Chemistry Program supports Professor Gudmundsdottir of the University of Cincinnati whose research will focus on selectively forming, detecting and investigating the reactivities of vinyl nitrene intermediates in solution and in the solid state. Direct irradiation of vinyl azides yields azirine products that can be attributed to formation of singlet vinyl nitrenes or can come from concerted rearrangement of the singlet excited state of the vinyl azides. Similarly, direct photolysis of 2H-azirine derivatives forms singlet biradicals. In order to bypass the singlet reactivity of the vinyl azide and 2H azirine precursors, vinyl azide and 2H-azirine derivatives with build-in triplet sensitizers have been prepared. The triplet vinyl nitrene intermediates that are expected to form by photolysis of these vinyl azides and 2H-azirines will be characterized using laser flash photolysis and matrix isolation. A detailed picture of the reactivities and kinetics of triplet vinyl nitrenes in solution will be obtained. Preliminary results imply that laser flash photolysis of 2H-azirine derivatives that have a built-in triplet sensitizer permit direct detection of triplet vinyl nitrene intermediates. These results have opened up a new field in nitrene chemistry and intermediates that have not previously been characterized can now be investigated. The solid state reactivity of these vinyl nitrene precursors will be studied in order to understand how their reactivity is affected by surrounding crystal lattices. The long term goal is to render these intermediates stable to explore their physical properties. The investigations that are proposed will lead to full characterization of triplet vinyl nitrenes in argon matrices and in solutions. Since the chemical reaction pathways for these intermediates in solution and in the solid state are largely unknown, they will be studied and identified. Molecular modeling will be performed to aid in the characterization of these compounds and to explain the reactivity of these intermediates. Better insight into the reactivity of triplet vinyl nitrenes will allow for the design of stable triplet nitrenes.With this award, the Organic and Macromolecular Chemistry Program supports Professor Gudmundsdottir of the University of Cincinnati whose research will study triplet nitrene intermediates that have high spin properties and are therefore potential candidates for organic magnets. The quest for new organic materials with magnetic properties arises from their potential to provide new technological advantages for applications such as magnetic shielding, magneto-optical switching, and 'smart' materials. The proposed research will train graduate students to do fundamental research in physical organic chemistry. These graduate students will in turn train undergraduate students to do research and expose high school students to scientific research. Emphasis will be placed on attracting minority high school students to work on the proposed research.

该奖项为辛辛那提大学的Gudmundsdottir教授提供了有机和高分子化学项目的支持，他的研究将集中于选择性地形成、检测和研究乙烯基硝化中间体在溶液和固态中的反应性。乙烯基叠氮化物的直接辐射产生的氮杂环产物可归因于单重态乙烯基硝烯的形成，或可来自叠氮乙烯基单重态激发态的协同重排。类似地，2H-氮杂环丙烷衍生物的直接光解形成单重态双自由基。为了绕过乙烯基叠氮化物和2H-氮杂环前驱体的单重态反应，合成了带有内嵌三重态增敏剂的叠氮乙烯基和2H-氮杂环丙烷衍生物。预计这些乙烯基叠氮化物和2H-氮杂环丙烷光解形成的三重态乙烯基硝烯中间体将用激光闪光光解和基质分离进行表征。将获得三重态乙烯基硝烯在溶液中的反应性和动力学的详细图像。初步结果表明，具有内置三重光敏剂的2H-氮杂环丙烷衍生物的激光闪光光解允许直接检测三重乙烯基尼龙中间体。这些结果开辟了硝烯化学的一个新领域，以前没有被表征的中间体现在可以被研究。为了了解它们的反应性如何受到周围晶格的影响，我们将研究这些乙烯基硝烯前驱体的固态反应性。长期目标是使这些中间体变得稳定，以探索它们的物理性质。所提出的研究将导致三重态乙烯基硝烯在Ar基质和溶液中的完全表征。由于这些中间体在溶液和固态中的化学反应路径在很大程度上是未知的，因此将对它们进行研究和鉴定。将进行分子模拟，以帮助表征这些化合物并解释这些中间体的反应性。通过这个奖项，有机和高分子化学项目支持辛辛那提大学的Gudmundsdottir教授的研究，他的研究将研究具有高自旋性质的三重态氮中间体，因此可能成为有机磁体的候选者。对具有磁性的新型有机材料的探索源于它们为磁屏蔽、磁光开关和智能材料等应用提供新的技术优势的潜力。这项拟议的研究将培养研究生从事物理有机化学的基础研究。这些研究生将反过来培养本科生进行研究，并让高中生接触科学研究。重点将放在吸引少数民族高中生参与拟议的研究上。