Pyrrole-modified Porphyrins - Chromophores of Basic and Applied Interests

化学部的化学合成计划支持康涅狄格大学化学系教员布鲁克纳教授的项目。血液是红色的，草是绿色的，因为有一类特殊的化合物--所谓的卟啉，它们在整个生物世界中发挥着不同的作用。除了这些自然作用外，这些高度有色的化合物还可能被用于各种“非天然”应用，从用作造影剂以改进生物组织的成像以更好地检测疾病，到用于电催化减少二氧化碳和化学传感努力。考虑到这一点，布鲁克纳教授正在开发策略，将自然产生的卟啉转化为具有原始化合物所不具备的特性的衍生品。这使得它们可以针对新的应用程序进行优化。此外，正在合成的衍生物非常适合回答有关卟啉的性质以及这些性质如何通过结构变化而系统地改变的基本问题。该项目教授研究生和本科生在制药和其他行业中使用的技术和方法。通过这种方式，学生们为进入职场做好了准备。布鲁克纳教授传统上一直活跃在化学教育中，并吸引在科学界代表性较低的学生参与这项最丰富多彩的研究工作。这项研究的跨学科和非常直观的性质使其成为外展活动的理想选择。这项提议的主要目标是开发将卟啉转化为吡咯修饰的卟啉(PMPs)的策略。PMP是通过用不同的杂环形式取代至少一个吡咯构筑块而从卟啉衍生的大环。从合成的卟啉开始，将采用一种相对较少探索的策略：激活卟啉的β-位，然后是环断裂和随后的环融合。本研究的重点是含有多个改性吡咯、中等大小的环或多个环状体系的PMP的生成。指导性的假设是，与其母化合物相比，这些修饰会导致电子性质的改变。将评估PMPs在几种生物(即光声组织成像中的造影剂)和技术(即电催化还原二氧化碳、化学传感)应用中的适用性。拟议的工作有赖于与一些生物、物理科学和工程学科的校内和校外(国际)专业小组的合作。该项目为不同领域的研究生提供了一个多学科和协作的培训场所，范围从有机和无机合成、物理有机化学、光物理学，到许多生物医学和工程应用。这为他们未来在工业界或学术界的职业生涯做好了准备。该提案还包括全年本科生研究项目，它将是系级REU计划的一部分。与卟啉相关的多学科研究活动非常适合在非技术期刊上传播，并使推广活动的主题丰富多彩。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。

The Chemical Synthesis Program of the Chemistry Division supports the project by Professor Brueckner, a faculty member in the Department of Chemistry at the University of Connecticut. Blood is red and grass is green because of a particular class of compounds - so called porphyrins, that fulfill diverse roles throughout the living world. In addition to these natural roles, these highly colored compounds can potentially be used for a variety of "non-natural" applications that range from their use as contrast agents to improve the imaging of biological tissue for better disease detection to their use for the electrocatalytic reduction of carbon dioxide and in chemosensing efforts. With this in mind, Professor Brueckner is developing strategies to convert naturally occurring porphyrins to derivatives that possess properties the original compounds do not have. This allows them to be optimized for new applications. In addition, the derivatives being synthesized are well-suited for answering fundamental questions about the properties of the porphyrins and how those properties can be systematically altered by changes in structure. The project teaches graduate and undergraduate students in the techniques and methodologies that are used in the pharmaceutical and other industries. In this way, students are prepared to enter the workplace. Professor Brueckner's has traditionally been active in chemical education and in attracting students underrepresented in science to this most colorful research work. The multidisciplinary and very visual nature of the research make it ideal for outreach activities.The main objective of this proposal is the development of strategies to convert porphyrins into pyrrole-modified porphyrins (PMPs). PMPs are macrocycles derived from porphyrins by formally replacing at least one pyrrolic building block with a different heterocycle. Starting from synthetic porphyrins, a relatively little explored strategy will be pursued: activation of the beta-position of porphyrins, followed by ring cleavage and subsequent ring-fusion. Focus in this study is the generation of PMPs containing multiple modified pyrroles, medium-size rings, or multiple annulated ring systems. The guiding hypothesis is that these modifications result in altered electronic properties when compared to their parent compounds. The suitability of the PMPs in several biological (i.e., contrast agents in photoacoustic tissue imaging) and technical (i.e. electrocatalytic reduction of CO2, chemosensing) applications will be evaluated. The proposed work relies on collaborations with intramural and extramural (international) specialty groups in a number of biological, physical sciences and engineering disciplines. The program offers a multidisciplinary and collaborative training ground for graduate students in diverse areas ranging from organic and inorganic synthesis, physical organic chemistry, photophysics, to a number of biomedical and engineering applications. This prepares them for future careers in industry or academia. The proposal also includes year-round undergraduate research projects, and it will be part of the departmental REU program. The multidisciplinary porphyrin-related research activities are ideal for dissemination in non-technical journals and make colorful subjects of outreach activities.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.