Oligopyrrole Macrocycles: Synthesis, Electronic Structure, Switching, and Communication

得克萨斯大学奥斯汀分校的乔纳森·L·塞斯勒教授和他的团队在该奖项的支持下，正在探索使血液变红、维生素B12变紫和草变绿的色素的新类似物。生物用来在短距离和长距离传输信号的化学交流原理也是研究的目标，例如，神经调节剂和臭鼬喷雾就是例证。通过使用小分子来触发下游的化学事件，可以在化学实验室内探索生物学的复杂性。考虑到这样的长期目标，已经设计了新的分子，预计将促进我们对分子结构如何影响关键性质的理解，如颜色、稳定性和与其他化学实体相互作用的能力。从长远来看，这有望导致新的分子系统的开发，这些系统可用于创建信息存储阵列，或用于新的医学模式，如光动力疗法，其中光用于治疗疾病。这个项目涉及跨越化学子领域的所有工作。因此，预计它将加强同事培训，并提供一支精通技术的劳动力队伍。它还应该为年轻的研究人员提供一个机会来发展从事与学术或非学术研究相关的职业所需的技能。就具体而言，该项目侧重于两类受益于先前NSF支持的寡吡咯大环，即扩展的卟啉和杯吡咯。这些分子单独和协同用于实现以下特定目标，分别涉及：1)制备新的二维和三维扩展的卟啉。这些体系允许探索氧化、还原和给体-受体相互作用对基态和激发态(反)芳香性的影响。它们还可以确定哪些设计特征控制着定域与离域的芳香性以及自由基与闭合壳层的共轭途径，从而在与血液色素类似物相关的基本结构-功能理解方面取得进展；2)能够访问多种离散状态的功能化杯吡咯体系的合成，如螺旋、胶囊和离散单体。在这一目标的背景下，正在使用手性的、非外消旋的吡啶功能化的杯[4]吡咯及其与金属化的扩展的卟啉的相互作用来探索非平衡效应；3)进一步探索先前报道的苯并四硫富瓦烯杯[5]吡咯-TCNQ系综，特别是在它能够释放离子和分子信使并调节各种下游化学反应的背景下。正在探索单体和胶囊型杯状吡咯与扩展的卟啉的组合，以期创建更复杂的信息传输系统。通过这种方式，可以评估结构对完全合成结构中级联样信号转导的影响。最终，这可能导致系统能够高度密集地存储信息或能够执行基本的计算功能。这个项目预计将在四年内完成。这一奖项反映了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。

Professor Jonathan L. Sessler and his team at The University of Texas at Austin supported by this award are exploring new analogues of the pigments that make blood red, vitamin B12 purple, and grass green. Also targeted for study are the principles of chemical communication that biology uses to transmit signals over short distances and long as exemplified, for instance, by neuroregulators and skunk sprays, respectively. By using small molecules to trigger downstream chemical events it could become possible to probe the complexity of biology within the chemical laboratory. With such long-term goals in mind, new molecules have been designed that are expected to advance our understanding of how molecular structure affects key properties, such as color, stability, and an ability to interact with other chemical entities. This is expected, in term, to lead to the development of new molecular systems that can be used to create information storage arrays or being used in the context of new medical modalities, such as photodynamic therapy, where light is used to treat diseases. This project involves work that spans the gamut of chemistry sub-areas. It is thus expected to enhance coworker training and provide a technically savvy workforce. It also should also provide an opportunity for young researchers to develop the skills needed to pursue academic or non-academic research-related careers.In terms of specifics, this project focuses on two classes of oligopyrrole macrocycles that have benefited from prior NSF support, namely expanded porphyrins and calixpyrroles. These molecules, alone and in concert, are being used to pursue the following specific aims, which involve respectively: 1) The preparation of new two- and three-dimensional expanded porphyrins. These systems allow explorations of the effects of oxidation, reduction, and donor-acceptor interactions on both ground and excited state (anti)aromaticity. They also allow determinations of which design features control localized vs. delocalized aromaticity and radical vs. closed shell conjugation pathways and thus advances in basic structure-function understanding as it relates to blood pigment analogues; 2) the synthesis of functionalized calixpyrrole systems that can access multiple discrete states, such as helices, capsules, and discrete monomers. In the context of this aim, off-equilibrium effects are being explored using chiral, non-racemic pyridine-functionalized calixpyrroles and their interactions with metalated expanded porphyrins; 3) further explorations of a previously reported benzotetrathiafulvalene calixpyrrole-TCNQ ensemble, particularly in the context of its ability to release ionic and molecular messengers and mediate various downstream chemical reactions. Combinations of monomeric and capsule-type calixpyrroles with expanded porphyrins, are being explored with a view to creating more complex information transfer systems. In this way, the effect of structure on cascade-like signal transduction in completely synthetic constructs can be assessed. Ultimately, this could lead to systems capable of highly dense information storage or able to perform rudimentary computing functions. This project is expected to be accomplished in four years.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.