Collaborative Research: CAS-SC: Development of Heavy Atom - Free Photocatalysts for Chemical Reactions

在化学系化学催化(CAT)和化学合成(SYN)计划、可持续发展的关键方面元计划(CAS)和多学科活动办公室(OMA)的支持下，芝加哥Loyola大学的Tatiana Esipova和康涅狄格大学的Tomyasu Mani正在开发一种新的无金属和无卤素催化剂家族，这些催化剂可通过可见光活化。一旦被激活，这些催化剂就能够促进许多化学反应。与这项工作相反，大多数可见光活化反应需要含有贵金属或卤素原子的催化剂，因此被认为在环境上是不可持续的。为了克服这一限制，Mani/Esipova合作团队正在使用计算建模来设计和优化他们的催化剂，并将随后在光驱动的转换中对其进行测试。除此之外，这个研究项目还为学生提供了宝贵的机会。参与这项工作的本科生和研究生，包括那些在科学界历来代表性不足的学生，正在发展智力，同时培养合成有机化学和物理化学的交叉点上的技能。这种培训对他们未来的职业生涯是有价值的，无论是在学术界还是在工业上。本研究旨在开发一类新的有机重原子无原子光氧化还原催化剂，该催化剂包含一个由正交电子供体-受体芳香族发色团组成的通用基序。一般来说，光催化剂吸收光线并产生电子激发态，以温和和受控的方式促进电子转移反应；因此，它们可以产生高活性的中间体，从而导致附加值的键形成事件。目前使用的大多数光氧化还原催化剂使用卤素或贵金属来增强这些激发态的产生。本研究开发的光氧化还原催化剂不仅利用了未被探索的光物理现象在pi-共轭有机分子中产生激发态，而且避免了包括金属和卤素在内的重金属原子的使用。这项研究展示了这种新型有机光还原催化剂的独特性质和多功能性。这项研究有望根据激发态的产生效率和相关的催化活性来建立给体-受体分子的结构-功能相关性。这项工作和对可持续催化剂的持续开发为继续探索和开发有机光氧化还原催化剂提供了坚实的基础。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。

With the support of the Chemical Catalysis (CAT) and Chemical Synthesis (SYN) programs in the Division of Chemistry, the Critical Aspects of Sustainability metaprogram (CAS) and the Office of Multidisciplinary Activities (OMA), Tatiana Esipova of Loyola University-Chicago and Tomoyasu Mani of the University of Connecticut are developing a new family of metal- and halogen-free catalysts that are activated by visible light. Upon activation these catalysts are capable of promoting a number of chemical reactions. In contrast to this work, most visible light-activated reactions require catalysts that contain precious metals or halogen atoms and therefore are not considered to be environmentally sustainable. With a focus on overcoming this limitation, the collaborative Mani/Esipova team is employing computational modeling to design and optimize their catalysts and will subsequently test them in light-driven transformations. In addition to all of this, this research program is providing valuable opportunities for students. Undergraduate and graduate students that are involved in this work, including students who have been historically underrepresented in the sciences, are developing intellectually while building skill sets that lie at the intersection of synthetic organic chemistry and physical chemistry. Such training is valuable for their future careers, be it in academia or industry.This research aims to develop a new family of organic heavy atom–free photoredox catalysts that contain a general motif that consists of orthogonal electron donor-acceptor aromatic chromophores. Generally speaking, photocatalysts absorb light and create electronically excited states that facilitate electron transfer reactions in a mild and controlled manner; as a result, they can produce highly reactive intermediates that lead to value-added bond-forming events. Most currently utilized photoredox catalysts employ halogens or precious metals to enhance the production of these excited states. The photoredox catalysts that are developed in this study not only take advantage of an underexplored photophysical phenomenon to produce excited states in pi-conjugated organic molecules, but they avoid the use of heavy atoms including metals and halogens. The research is demonstrating the unique properties and versatility of this new class of organic photoredox catalysts. This research is expected to establish structure-function correlations of donor-acceptor molecules in terms of the efficiency of the generation of the excited state and the associated catalytic activity. This work and the continued development of sustainable catalysts is providing a firm foundation for the continued exploration and the development of organic photoredox catalysis.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.