CAREER: Synthetic Strategies to Optimize Luminescence and Photoredox Properties of Organometallic Complexes

在这个由化学系化学结构、动力学和机理B项目资助的职业项目中，休斯顿大学化学系的Thomas S.Teets教授正在设计新的合成策略来制备发光和光活性的Ir络合物。这项研究的第一个目标是开发能够发出蓝光的化合物，这种化合物可能会在长寿命、高效率的有机发光二极管(LED)彩色显示器中发挥作用。第二个目标是开发在光谱的近红外(NIR)区域发射的化合物。这类化合物可能对生物传感和成像有用。第三个目标是针对有机合成中光催化剂的化合物，这对新药物的开发具有重要意义。与这些研究方向相辅相成的是旨在改进普通化学教学、向K-12学生介绍光化学概念并使普通公众参与科学学习的教育和推广部分。蒂茨教授正在制作一本在线免费提供的多媒体普通化学教科书，以造福于低收入学生。他还开发了一个名为“点亮分子”的K-12实验模块，向年轻学生介绍光与化合物的相互作用。最后，他制作了一个名为《色彩的化学》的公开系列讲座，向艺术爱好者介绍视觉艺术中创造色彩背后的化学原理。在这个项目中，Teets教授研究了一类由无环二氨基卡宾和其他非传统卡宾配体支撑的新型蓝色磷光环状金属Ir络合物。这些卡宾基团破坏了干扰配体-场态的稳定性，从而提高了这些蓝色发光化合物的量子产率和稳定性。在光谱的另一个极端，制备了由富电子、pi给体的辅助配体支撑的近红外发射的双环金属Ir配合物。富含电子的辅助配体破坏了以Ir为中心的最高占据分子轨道(HOMO)的稳定性，从而增加了激发态金属到配体的电荷转移(MLCT)特性，增加了辐射速率，提高了光致发光量子产率。利用类似的设计元素，可以开发出有效的可见光还原剂。这些环金属Ir化合物具有非常还原的激发态，并作为有机转化的光催化剂，涉及到强底物键的光激活。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。

In this CAREER project, funded by the Chemical Structure, Dynamics & Mechanisms B Program of the Chemistry Division, Professor Thomas S. Teets of the Department of Chemistry at the University of Houston is designing new synthetic strategies to prepare luminescent and photoactive iridium complexes. The first aim of the research develops compounds that emit blue light and may function in long-lived, high-efficiency organic light-emitting diode (LED) color displays. The second aim develops compounds that emit in the near infrared (NIR) region of the spectrum. Such compounds may be useful for biological sensing and imaging. The third aim targets compounds for photocatalysts in organic synthesis, which is important for the development of new pharmaceuticals. These research directions are complemented by an education and outreach component that aims to improve general chemistry instruction, introduce K-12 students to concepts of photochemistry, and to engage the general public in scientific learning. Professor Teets is creating an online, freely available multimedia general chemistry textbook to benefit low-income students. He also develops a K-12 lab module titled "Lighting Up Molecules" that introduces young students to the interactions of light with chemical compounds. Finally, he produces a public lecture series called "The Chemistry of Color" to introduce art enthusiasts to the chemical principles behind the creation of colors in visual art.In this project, Professor Teets studies a new class of blue phosphorescent cyclometalated iridium complexes supported by acyclic diaminocarbene and other unconventional carbene ligands. These carbene moieties destabilize interfering ligand-field states and thereby improve the quantum yield and stability of these blue-emitting compounds. In the opposite extreme of the spectrum, NIR-emitting bis-cyclometalated iridium complexes supported by electron-rich, pi-donating ancillary ligands are prepared. The electron-rich ancillary ligand destabilizes the iridium-centered Highest Occupied Molecular Orbital (HOMO), which increases the excited-state metal-to-ligand charge-transfer (MLCT) character, augments radiative rates, and improves photoluminescence quantum yield. Using similar design elements, potent visible-light photoreductants are developed. These cyclometalated iridium compounds have very reducing excited states and function as photocatalysts for organic transformations that involve photoactivation of strong substrate bonds.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.