Pyrrole-Modified Porphyrins: Platforms to Probe the Malleability of Porphyrinoid Conformation and Aromaticity

在化学系化学结构、动力学和机制-B项目的支持下，康涅狄格大学的布鲁克纳教授正在研究卟啉和绿素，这是参与许多新陈代谢过程和采光的“生命色素”的成员。这些调查的目的是了解它们的基本属性，这些属性使它们变得对生命如此重要。制备的新化合物还具有表明它们在非自然应用中的用途的性质。例如，一些改性材料比自然材料更具弹性，在变形时会改变其颜色。因此，它们适合产生可使物理应力可见的材料；这对许多工程学科很重要。二氧化碳转化为有价值的产品是我们这个时代迫切需要解决的问题之一。在这些转化反应中，对一些修饰的卟啉金属络合物的研究扩大了我们对如何最好地做到这一点的理解。这些研究将为学生提供从有机和无机合成到物理有机化学等领域的多学科和协作培训基础，并接触光物理和一些生物医学和工程应用。这将为学生在未来的工业、学术或公共服务领域的职业生涯做好准备。这项拟议的研究重点是通过逐步合成操作卟啉来正式取代卟啉中的吡咯类积木。这产生了一系列所谓的吡咯修饰的卟啉(PMP)，其中包含一个或多个非吡咯构建块。人们正在研究通常具有戏剧性的构象和电子效应--特别是当构建块比它们所取代的五元吡咯更大的时候。这些研究的一个重点是替换对PMP的芳香性的影响。对卟啉大环内发生的化学转化的评价有助于合理设计新的实用的卟啉类化合物。对机械变色聚合物中选择构象柔性的PMPs的评价描述了PMPs在实现智能材料方面的应用范围和限制。一些PMP表明它们具有充当电子接收器的能力。这将通过使用它们的Co(II)络合物在二氧化碳的电催化多电子还原中进行探索。这些努力的成功有可能在卟啉调节方面提供重要的长期经验教训，以构建有用的功能。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

With the support of the Chemical Structure, Dynamics, and Mechanisms-B program in the Division of Chemistry, Professor Brueckner of the University of Connecticut is studying porphyrins and chlorins, members of the ‘pigments of life’ involved in many metabolic processes and light harvesting. These investigations aim at the understanding of their fundamental properties that allowed them to become so important for life. The new compounds prepared also possess properties that suggest their utilization in non-natural applications. For instance, some modified materials are more flexible than their natural counterparts and change their color when deformed. They are therefore suitable to generate materials that can make physical stress visible; this is important for many engineering disciplines. The conversion of carbon dioxide to valuable products is one of the pressing problems of our time. The study of some metal complexes of the modified porphyrins in these conversions expands our understanding how best to do this. These studies will offer a multidisciplinary and collaborative training ground for students in areas ranging from organic and inorganic synthesis to physical organic chemistry, with exposure to photophysics and a number of biomedical and engineering applications. This will prepare students well for future careers in industry, academia, or public service.The proposed study focuses on the formal replacement of a pyrrolic building block in porphyrins by stepwise synthetic manipulation of porphyrins. This generates a family of so-called pyrrole-modified porphyrins (PMPs) incorporating one or more non-pyrrolic building blocks. The often dramatic conformational and electronic effects – especially when the building blocks are larger than the five-membered pyrrole they replace – are being studied. One focus in these studies is the impact the replacement has on the aromaticity of the PMPs. An appreciation for the chemical transformations taking place within the constraints of a porphyrinic macrocycle assists in the rational design of novel porphyrinoids of utility. The evaluation of select conformationally flexible PMPs in mechanochromic polymers delineates the scopes and limits of utilizing PMPs in the realization of smart materials. Some PMPs suggest their capacity to act as electron sinks. This will be probed by the use of their Co(II) complexes in electro-catalytic multi-electron reductions of carbon dioxide. Success in these endeavors has the potential to provide important long term lessons in porphyrin tuning to build in useful function.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.