Redox and Excited State Properties of Oligothiophene-Bearing Ru(II) Photodrugs

在化学结构、动力学和机理-B（CSDM-B）项目的支持下，德克萨斯大学阿灵顿分校的Sherri麦克法兰教授将研究分子构象、电离能力和分子间相互作用如何影响光敏剂的行为，特别是含寡聚噻吩的钌化合物。光敏剂是利用光能促进期望的物理过程或化学转化的化合物。这些分子在太阳能转换到化学催化以及光医学等领域都有应用。该项目的重点是光敏剂类，显示出癌症治疗的希望，并可能遵循一种独特的多模式行动，结合单重态氧敏化的光化学反应和分子间的光化学反应。该项目将使用配位化学加上电子物理和电化学技术的工具来探索异构，团聚和限制以及环境对这些途径的作用。拟议的工作将培养研究生和本科生在化学，生物学，物理学和工程学的关系高度多学科的研究。这种在合成、无机化学物理学和光谱学以及电化学方面的多方面培训将有助于培养未来的科学和技术人才。更广泛的影响目标旨在提高科学素养和解决研究中的教育公平问题。麦克法兰团队特别关注解决本科研究中的教育公平问题，并通过为本科STEM学生提供基于实验室的研究经验（CURES），利用具有社会影响力的临床项目提高科学素养。该项目旨在为未来的领导者提供科学交流技能，并让他们接触到企业家精神，因为这与将科学发现从实验室推向社会有关。在该奖项下，Sherri麦克法兰教授和她的团队将研究含低聚噻吩的Ru（II）络合物的氧化还原和激发态性质，在从太阳能转换到光医学的领域中作为光敏剂具有重要应用的化合物。咪唑并[4，5-f][1，10]菲咯啉（IP）配体与链长为n的寡聚噻吩（nT）形成平面化的最低能量三重态，具有显著的配体内电荷转移（ILCT）特征。低聚噻吩是氧化还原活性的，并且相邻的IP基团可以使质子耦合电子转移（PCET）能够促进来自3 ILCT状态的催化光氧化还原反应。这些电荷分离的激发态也可以进行化学二聚化并产生单线态氧。该项目旨在为这些系统在简单溶剂和复杂的生物环境中建立一个生物物理模型。每个系统将从分子结构，氧化还原化学和生物物理学的角度进行研究，并对光疗机制产生长期影响。UTA团队将合成和表征低聚噻吩附加的Ru（II）络合物[Ru（LL）2（IP-nT）]2+，以探测各种因素对所提出的PCET促进途径的影响：电离态，激发态构象，三重态能量和特征，以及双分子过程。合成，光谱和电化学技术将被用来测试的重要性与CT字符和可电离基团的nT为基础的三重峰多模式的行动和探测如何激发态动力学的影响，在生物界面的基础上，如电离，构象和异构的因素。 该项目旨在推动配位化学、光化学和光物理学领域的发展，并最终推动光医学领域的发展。该奖项反映了NSF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。

WIth support from the Chemical Structure, Dynamics, and Mechanism-B (CSDM-B) program, Professor Sherri McFarland at the University of Texas, Arlington will interrogate how molecular conformation, ionizability, and intermolecular interactions influence the behavior of photosensitizers, particularly oligothiophene-containing ruthenium compounds. Photosensitizers are compounds that harness the light energy to facilitate a desirable physical process or chemical transformation. Such molecules have utility in fields spanning solar energy conversion to chemical catalysis, and also photomedicine. This project focuses on a photosensitizer class that shows promise for cancer therapy and may follow a unique type of multimodal action that combines photocatalysis and intermolecular photochemical reactions with singlet oxygen sensitization. The project will use the tools of coordination chemistry plus photophysical and electrochemical techniques to explore the roles of isomerism, agglomeration and confinement, and environment on these pathways. The proposed work will train graduate students and undergraduates in highly multidisciplinary research at the nexus of chemistry, biology, physics, and engineering. This multifaceted training in synthesis, inorganic photophysics and spectroscopy, and electrochemistry will help to prepare the future workforce in science and technology. The broader impact objectives are aimed at improving scientific literacy and addressing educational equity in research. The McFarland team is particularly focused on addressing educational equity issues in undergraduate research and improving scientific literacy using bench-to-bedside projects with societal impact through curriculum-based research experiences (CUREs) for undergraduate STEM students. The project aims to equip tomorrow’s leaders with skills in science communication and expose them to entrepreneurship as it relates to bringing scientific discoveries from the laboratory to society.Under this award, Professor Sherri McFarland and her team will examine the redox and excited state properties of oligothiophene-containing Ru(II) complexes, compounds that have important applications as photosensitizers in fields ranging from solar energy conversion to photomedicine. Imidazo[4,5-f][1,10]phenanthroline (IP) ligands appended to oligothiophenes (nT) of sufficient chain length n adopt planarized lowest-energy triplet states that are of significant intraligand charge transfer (ILCT) character. Oligothiophenes are redox active, and the neighboring IP group may enable proton coupled electron transfer (PCET) to facilitate catalytic photoredox reactions from the 3ILCT states. These charge-separated excited states may also undergo chemical dimerization and generate singlet oxygen. The project aims to develop a photophysical model for these systems in simple solvents and in complex biological environments. Each system will be studied from the point of view of molecular structure, redox chemistry and photophysics, with longer term implications for phototherapy mechanisms. The UTA team will synthesize and characterize oligothiophene-appended Ru(II) complexes, [Ru(LL)2(IP-nT)]2+, to probe the effects of various factors on the proposed PCET-facilitated pathways: ionization state, excited state conformation, triplet energy and character, and bimolecular processes. Synthetic, spectroscopic, and electrochemical techniques will be used to test the importance of nT-based triplets with CT character and ionizable groups for multimodal action and probe how the excited state dynamics are influenced at biological interfaces based on factors such as ionization, conformation, and isomerism. This project aims to advance the fields of coordination chemistry, photochemistry and photophysics, and ultimately photomedicine, in the longer term.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.