Photothermal Catalysis: Using light to thermally generate reactive intermediates with temporal and spatial control

项目摘要 光子驱动的过程已经成为实现具有挑战性的键断裂和 键的形成。光催化提供了低能量光的时间和空间控制的好处，这具有 在从简单的起始材料高效构建分子复杂性方面具有广泛的优势。这个 明智地选择光催化剂可以实现其他形式的光催化剂很少能达到的反应精度 催化和加热。光催化的一个未得到充分利用的领域是光热转化。特异度照射 具有可见光的纳米颗粒或染料在光热转换过程中会产生强烈的温度梯度。 与整体加热相反，在整体加热中，反应介质上的温度保持一致，基质将 只有在时间加热下，才能体验到激发几纳米范围内的热能。因此， 这一过程将使用辐射来驱动高温下的化学过程，具有时间和空间 控制力。空间控制能够在不竞争双分子的情况下选择性地形成高活性物种 副作用。 拟议的研究包括探索光热催化使用的三个基本项目。 能够利用可见光辐射合成复杂分子。第一，高温高温 在温和的情况下，将使用碳基纳米颗粒和可见光照射实现重排 条件。这一策略将使复杂产品的合成一般不需要热分解。 与整体热解有关。此外，各种光热剂的鉴定和合成 精心设计将产生更有效的催化剂。在第二个项目中，光热供暖将产生 碳中心自由基通过C-C键均解。截获这些高活性中间体将锻造 在扩环反应和分子内环化反应中形成新的C-C键。特定光热剂的设计 将使分子间环扩张建立分子复杂性。在第三个项目中，C-C键 项目二中确定的均解反应将用于原子经济性的动态动力学拆分。 富含对映体药物化合物的合成。乳剂会将温度梯度限制在 胶束使热异构化反应与高选择性的酶反应偶联。 这三个项目结合在一起，将加深对光热催化和光的影响的理解。 以及产生温度梯度时的强度。彻底了解这些温度梯度如何 利用可见光的空间和时间控制进行高温反应将使新的 此前未实现的合成债券脱节。

Project Summary Photon-driven processes have emerged as a powerful tool for achieving challenging bond cleavage and bond formation. Photocatalysis offers the benefit of temporal and spatial control with low energy light, which has been widely advantageous for efficiently building molecular complexity from simple starting materials. The judicious choice of photocatalysts enables the precision of reactivity that is rarely achieved with other forms of catalysis and heating. An underused area of photocatalysis is photothermal conversion. Irradiation of specific nanoparticles or dyes with visible light creates intense thermal gradients in a photothermal conversion process. In contrast to bulk heating, where the temperature remains uniform across a reaction medium, substrates would only experience thermal energy within a few nanometers of excitation under temporal heating. Consequently, this process would use irradiation to drive chemical processes at high temperatures with temporal and spatial control. Spatial control enables the selective formation of highly reactive species without competing bimolecular side reactions. The proposed research comprises three fundamental projects exploring the use of photothermal catalysis to enable the synthesis of complex molecules using visible light irradiation. First, high-temperature thermal rearrangements will be achieved using carbon-based nanoparticles and visible light irradiation under mild conditions. This strategy will enable the synthesis of complex products without thermal decomposition generally associated with bulk thermolysis. Additionally, the identification of various photothermal agents and synthetic elaborations will generate more efficient catalysts. In the second project, photothermal heating will generate carbon-centered radicals through C–C bond homolysis. Intercepting these highly reactive intermediates will forge new C–C bonds in ring expansion reactions, in intramolecular cyclizations. Specific photothermal agent design will enable intermolecular ring expansions to build molecular complexity. In a third project, the C–C bond homolysis reactions identified in project two will be used in dynamic kinetic resolutions for atom economical synthesis of enantioenriched pharmaceutical compounds. Emulsions will confine thermal gradients to within micelles enabling the coupling of thermal epimerization reactions with highly selective enzymatic reactions. Combined, these three projects will develop an understanding of photothermal catalysis and the effect of light and intensity on generation of thermal gradients. A thorough understanding of how these thermal gradients can be leveraged for high temperature reactions with the spatial and temporal control of visible light will enable new synthetic bond disconnections previously unrealized.