CAS: CAREER: Synthetic Designs Toward Wavelength-Tunable Production of Reactive Intermediates for Selective Photooxidation

在化学系化学结构、动力学和机理B项目的支持下，北卡罗来纳大学格林斯伯勒分校化学和生物化学系的沙布南·赫马蒂安致力于开发一种新型光催化剂，将廉价和无活性的原材料转化为增值化学品。这些潜在的催化剂利用了空气中氧气的氧化能力，作为一种绿色的终端氧化剂，以及光能作为一种可持续的试剂，形成新的和难以获得的化学键。本研究的目的是通过调节光源的能量来控制光化学产物和反应的选择性。该项目的结果有可能实现更快和可调的反应，这在药物和其他精细化学品的合成中是相关的。这项工作为各级科学家在光化学、合成、光谱学、氧化还原和动力学领域提供了一个坚实的跨学科培训平台。这一群体也处于有利地位，能够提供最高水平的教育和培训，使学生在职业生涯早期(即当地高中和社区大学学生以及一年级本科生和研究生)参与科学工作，促进化学领域的招聘和留住。寻找高效的均相光催化剂，在温和的条件下，以氧气为末端氧化剂选择性氧化底物，一直是合成化学的重要目标。这项工作旨在设计和开发一类新型的光催化剂，其中金属-氧化学导致氧的协同活化和氧桥联异双核体系的形成。在所开发的体系中，通过电荷转移激发态驱动的两个独特的金属氧键的光活化，可以获得两个不同的反应性高价金属氧中间体。在这个项目中，我们将研究已开发的氧桥结构的结构-功能关系，以了解基态中通过氧桥配体的各个催化位置之间的电子交换耦合如何以及在多大程度上影响电荷转移转变，以及这种耦合如何在整体光活性中表现出来。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。

With support from the Chemical Structure, Dynamics & Mechanisms B Program of the Chemistry Division, Shabnam Hematian of the Department of Chemistry and Biochemistry at the University of North Carolina at Greensboro aims to develop a new class of photocatalysts to transform cheap and unreactive raw materials into value-added chemicals. These potential catalysts exploit the oxidizing power of oxygen in the air, as a green terminal oxidant, and the energy of light as a sustainable reagent for forming new and difficult-to-access chemical bonds. The goal of this research is to control the photochemical outcome and reaction selectivity through modulating the energy of the light source. Results from this project have the potential to enable faster and tunable reactions which are relevant in the synthesis of pharmaceuticals and other fine chemicals. This work provides a solid interdisciplinary training platform in the fields of photochemistry, synthesis, spectroscopy, redox, and kinetics for scientists at all levels. This group is also well-positioned to provide the highest level of education and training to engage students in science early in their careers (i.e., local high school and community college students as well as first-year undergraduate and graduate students), promoting recruitment and retention in the chemistry field. The discovery of effective homogeneous photocatalysts for the selective oxidation of substrates under mild conditions using dioxygen as the terminal oxidant remains an important objective in synthetic chemistry. The proposed work seeks to design and develop a new class of photocatalysts in which metal-dioxygen chemistry leads to the cooperative activation of dioxygen and formation of oxo-bridged heterobinuclear systems. In the developed systems, two different reactive high-valent metal-oxo intermediates are accessible through the photoactivation of two unique metal-oxo bonds which are driven from charge transfer excited states. In this project, the structure-function relationships of the developed oxo-bridged constructs will be investigated to understand how and to what extent electronic exchange coupling between the individual catalytic sites through an oxo bridging ligand in the ground state impacts the charge transfer transitions and how this coupling manifests itself in overall photoactivity.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.