Pyrrole-modified Porphyrins - Chromophores of Basic and Applied Interests

化学部门的化学合成项目支持康涅狄格大学化学系教员Brueckner教授的项目。血是红色的，草是绿色的，这是因为一类特殊的化合物——卟啉，它们在生物世界中扮演着不同的角色。除了这些天然作用之外，这些高度着色的化合物还可以潜在地用于各种“非天然”应用，从用作造影剂以改善生物组织的成像以更好地检测疾病到用于二氧化碳的电催化还原和化学传感工作。考虑到这一点，布鲁克纳教授正在研究将天然存在的卟啉转化为具有原始化合物所不具有的特性的衍生物的策略。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性质以及这些性质如何通过结构变化而系统改变的基本问题。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。这样，学生们就为进入职场做好了准备。布鲁克纳教授传统上一直积极从事化学教育，并吸引在科学领域代表性不足的学生参与这项最丰富多彩的研究工作。该研究的多学科和非常直观的性质使其成为推广活动的理想选择。本提案的主要目标是发展将卟啉转化为吡咯修饰的卟啉（pmp）的策略。pmp是由卟啉通过用不同的杂环取代至少一个吡啶构建块而衍生的大环。从合成卟啉开始，一个相对较少探索的策略将被追求：激活卟啉的β位置，然后是环切割和随后的环融合。本研究的重点是生成含有多个修饰吡咯、中等大小环或多个环状环体系的pmp。指导性的假设是，与母体化合物相比，这些修饰导致了电子性质的改变。将评估pmp在几种生物（即光声组织成像中的造影剂）和技术（即二氧化碳的电催化还原，化学传感）应用中的适用性。拟议的工作依赖于与一些生物、物理科学和工程学科的校内和校外（国际）专业小组的合作。该项目为研究生提供了一个多学科和协作的培训基地，涵盖有机和无机合成、物理有机化学、光物理学以及一些生物医学和工程应用等各个领域。这为他们未来在工业界或学术界的职业生涯做好了准备。该提案还包括全年的本科生研究项目，它将成为部门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进行传播，并使推广活动成为丰富多彩的主题。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值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.