• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文学位 >Applications of photoinduced electron transfer chemistry: Photoremovable protecting groups and carbon dioxide conversion.
【24h】

Applications of photoinduced electron transfer chemistry: Photoremovable protecting groups and carbon dioxide conversion.

机译：光致电子转移化学的应用：可光除去的保护基和二氧化碳转化。

获取原文
获取原文并翻译 | 示例
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Traditional organic chemistry has long been dominated by ground state thermal reactions. The alternative to this is excited state chemistry, which uses light to drive chemical transformations. There is considerable interest in using this clean renewable energy source due to concerns surrounding the combustion byproducts associated with the consumption of fossil fuels. The work presented in this text will focus on the use of light (both ultraviolet and visible) for the following quantitative chemical transformations: (1) the release of compounds containing carboxylic acid and alcohol functional groups and (2) the conversion of carbon dioxide into other useable chemicals.;Chapters 1-3 will introduce and explore the use of photoremovable protecting groups (PPGs) for the spatiotemporal control of molecular concentrations. Two new PPGs are discussed, the 2,2,2-tribromoethoxy group for the protection of carboxylic acids and the 9-phenyl-9-tritylone group for the protection of alcohols. Fundamental interest in the factors that affect C--X bond breaking has driven the work presented in this text for the release of carboxylic acid substrates. Product analysis from the UV photolysis of 2,2,2-tribromoethyl-(2'-phenylacetate) in various solvents results in the formation of H--atom abstraction products as well as the release of phenylacetic acid. The deprotection of alcohols is realized through the use of UV or visible light photolysis of 9-phenyl-9-tritylone ethers. Central to this study is the use of photoinduced electron transfer chemistry for the generation of ion diradicals capable of undergoing bond-breaking chemistry leading to the release of the alcohol substrates.;Chapters 4 and 5 will explore the use of N-heterocyclic carbenes (NHCs) as a catalyst for the photochemical reduction of carbon dioxide. Previous experiments have demonstrated that NHCs can add to CO2 to form stable zwitterionic species known as N-heterocylic-2-carboxylates (NHC--CO 2). Work presented in this text illustrate that the stability of these species is highly dependent on solvent polarity, consistent with a lengthening of the imidazolium to carbon dioxide bond (CNHC--CCO2). Furthermore, these adducts interact with excited state electron donors resulting in the generation of ion diradicals capable of converting carbon dioxide into formic acid.
机译：长期以来，传统的有机化学一直以基态热反应为主。替代方法是激发态化学，它使用光来驱动化学转化。由于担心与化石燃料消耗相关的燃烧副产物，使用这种清洁的可再生能源引起了极大的兴趣。本文中的工作将集中于光（紫外线和可见光）的使用，以进行以下定量化学转化：（1）释放含有羧酸和醇官能团的化合物，以及（2）将二氧化碳转化为其他可使用的化学物质。第1-3章将介绍和探讨光可去除保护基（PPG）在时空上控制分子浓度的用途。讨论了两种新的PPG，用于保护羧酸的2,2,2-三溴乙氧基和用于保护醇的9-苯基-9-三苯甲基。人们对影响C-X键断裂的因素的基本兴趣推动了本文中有关羧酸底物释放的工作。在各种溶剂中对2,2,2-三溴乙基-（2'-苯乙酸）进行紫外线光解的产物分析结果导致H-原子提取产物的形成以及苯乙酸的释放。通过使用9-苯基-9-三苯甲基醚的紫外线或可见光光解可实现醇的脱保护。这项研究的核心是使用光诱导电子转移化学来生成能够进行键断裂化学反应从而释放出醇底物的离子双自由基;第4章和第5章将探讨N-杂环卡宾（NHCs）的使用）作为光化学还原二氧化碳的催化剂。先前的实验表明，NHC可以添加到CO2中形成稳定的两性离子物质，称为N-杂环-2-羧酸盐（NHC--CO 2）。本文中的工作表明，这些物质的稳定性高度依赖于溶剂的极性，这与咪唑鎓与二氧化碳键（CNHC--CCO2）的延长相一致。此外，这些加合物与激发态电子供体相互作用，导致生成能够将二氧化碳转化为甲酸的离子双自由基。

著录项

  • 作者

    Denning, Derek Michael.;

  • 作者单位

    University of Maryland, College Park.;

  • 授予单位 University of Maryland, College Park.;
  • 学科 Organic chemistry.;Chemistry.;Physical chemistry.
  • 学位 Ph.D.
  • 年度 2016
  • 页码 290 p.
  • 总页数 290
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号