Advancing the Synthesis and Applications of Pyrrole-Modified Porphyrins

康涅狄格大学化学系的Christian Brueckner教授领导的研究小组，在化学系化学结构、动态和机制B项目的资助下，将从天然存在的卟啉分子类中开发出许多染料。这种化合物类使血液（血红蛋白）呈深红色。通过在特定位置插入、替换或删除原子来略微改变卟啉的分子结构，可以改变其光学性质。因此，例如，染料可以吸收大部分阳光，使其成为光收集应用的有吸引力的选择。其他染料拥有的特性可能使它们成为医学光学成像的造影剂，这可能会产生更广泛的科学影响。这项工作始于合成策略的发展，以产生新的染料。一旦制备好，它们的物理性质就会被评估。这项工作具有很强的跨学科性质，为研究生和本科生提供了良好的培训，使他们成为一支现代化和包容性的劳动力队伍。该基金的主要目标是开发将卟啉转化为吡啶修饰卟啉（pmp）的策略，通过用不同的杂环正式取代至少一个吡啶构建块，从卟啉衍生出大环。从中芳基卟啉或八乙基卟啉开始，将采用一种很少探索但通用的策略：激活卟啉的β位置，然后进行环切割和随后的环融合。这产生含有一个或两个五、六和七元非吡咯杂环的pmp，并且还可以通过β -到中苯基键结合扩展的pi系统。这项工作的指导假设是，与它们的母体卟啉或氯相比，这些修饰导致电子性质发生了巨大的变化。特别是它们的最长吸光度和荧光波长，它们的超色光谱，在某些情况下，它们的全色光谱，以及它们有效的非辐射弛豫过程，许多pmp具有显著的潜在用途的光物理性质。与专业小组合作，将测试它们在选定领域的应用。结构-物理性质的关系也将发展。

Funded by the Chemical Structure, Dynamic & Mechanism B Program of the Chemistry Division, the research group led by Professor Christian Brueckner of the Department of Chemistry at the University of Connecticut will develop a number of dyes derived from the naturally occurring molecule class called porphyrins. This compound class gives blood (hemoglobin) its deep red color. Altering the molecular structure of the porphyrin slightly by insertion, replacement, or deletion of atoms at defined positions varies their optical properties. Thus, for example, dyes are derived that absorb a large portion of sunlight, making them attractive options for light-harvesting applications. Other dyes possess properties that may make them useful as contrast agents for optical imaging in medicine, a potentially notable broader scientific impact. The work begins with the development of the synthetic strategies to generate the novel dyes. Once prepared, their physical properties are evaluated. The strong interdisciplinary nature of the work provides excellent training for graduate and undergraduate students for a modern and inclusive workforce.The main objective of this grant is the development of strategies to convert porphyrins into pyrrole-modified porphyrins (PMPs), macrocycles derived from porphyrins by formally replacing at least one pyrrolic building block with a different heterocycle. Starting from meso-arylporphyrins or octaethylporphyrin, a little explored but versatile strategy will be pursued: activation of the beta position of porphyrins, followed by ring cleavage and subsequent ring-fusion. This generates PMPs containing one or two five, six, and seven-membered non-pyrrolic heterocycles and that may also incorporate extended pi-systems through beta-to-meso-phenyl linkages. The guiding hypothesis of the work is that these modifications result in drastically altered electronic properties when compared to their parent porphyrins or chlorins. Particularly with respect to their longest wavelength of absorbance and fluorescence, their hyperchromic and, in some cases, panchromic spectra, and in their efficient non-radiative relaxation processes, many PMPs possess remarkable photophysical properties of potential utility. In collaboration with specialty groups, their application in select fields will be tested. Structure-physical properties relationships will also be developed.