LEAPS-MPS: Heterogeneous Asymmetric Catalysis with Chiral Metal Clusters

在这个由NSF化学部管理的项目中，南卫理公会大学的Anindita Das教授和她的学生将进行研究，旨在通过在金属簇表面安装新的手性配体，将配体导向的不对称催化从均相体系转移到非均相体系。不对称催化反应是合成光学活性化合物的一种有效途径，在医药领域具有重要意义。例如，在过去5年中，FDA批准的小分子药物中有75%以上是手性化合物。近年来，化学家们通过合理设计手性配体来模拟酶的活性位点，在开发均相不对称有机催化剂以及过渡金属配合物催化剂方面取得了巨大的成功。然而，由于通过常规途径合成的纳米颗粒的固有多分散性，将这种策略用于工业相关的基于多相金属纳米颗粒的催化剂以实现“预测性多相不对称催化”是一个长期的挑战。为了解决这一限制，Das教授和她的学生将开发原子精确的模型金属簇，其表面将具有新的手性配体来调节其催化活性，类似于均相不对称催化剂。他们的研究可以帮助确定与基于金属簇的模型催化剂的不对称催化活性相关的关键参数，从而在未来实现更好的非均相催化剂设计。 这项研究与众多外展活动相结合，以吸引和鼓励代表性不足的第一代或低收入学生攻读STEM学位和职业。这些措施包括在附近的高中和MSI组织研讨会和演示实验，以促进公众对科学和研究的认识。此外，Das教授和她的学生们还将进行关于隐藏的内隐偏见和培养文化智能的培训，以创造一个包容和支持的实验室环境。Das教授和她的学生将合成和表征一系列由新手性配体保护的原子精确金属簇。这些簇的合成机制将通过各种技术，如单晶X射线晶体学，NMR，UV-可见光和荧光光谱，圆二色谱（CD）光谱，电化学分析和质谱进行研究。这些合成准则将被应用到手性金属簇合物中，以研究模型不对称变换中的协同作用的影响。最终，从这项研究中产生的设计规则可以广泛应用于其他类别的异质纳米材料，以了解和调整其原子精度的非对称催化性能。该奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

In this project managed by the Chemistry Division at NSF, Professor Anindita Das and her students at Southern Methodist University will perform studies that aim to transpose ligand-directed asymmetric catalysis from homogeneous to heterogeneous systems by installing new chiral ligands on the surfaces of metal clusters. Asymmetric catalytic reactions represent a powerful way to synthesize optically active compounds which have tremendous implications in medicine. For instance, more than 75% of the small-molecule drugs approved by the FDA in the last 5 years are chiral compounds. Over the years, chemists have achieved tremendous success in developing homogeneous asymmetric organocatalysts as well as transition-metal complex catalysts by rationally designing chiral ligands which mimic the active sites of enzymes. However, using this strategy for industrially relevant heterogeneous metal nanoparticle-based catalysts to achieve “predictive heterogeneous asymmetric catalysis” is a longstanding challenge owing to the inherent polydispersity of nanoparticles synthesized by conventional routes. To address this limitation, Professor Das and her students will develop atomically precise model metal clusters the surfaces of which will feature new chiral ligands to tune their catalytic activity, analogous to homogeneous asymmetric catalysts. Their studies could help identify the critical parameters related to asymmetric catalytic activity of metal cluster-based model catalysts leading to better heterogeneous catalyst design in future. This research is integrated with numerous outreach activities to engage and encourage underrepresented, first-generation, or low-income students to pursue STEM degrees and careers. These include organizing workshops and demo-experiments at nearby high schools and MSIs to promote public literacy about science and research. Additionally, trainings on hidden implicit biases and cultivating cultural intelligence will be undertaken to create an inclusive and supportive lab environment.Professor Das and her students will synthesize and characterize a series of atomically precise metal clusters protected by new chiral ligands. The synthetic mechanisms of these clusters will be investigated by various techniques such as single crystal X-ray crystallography, NMR, UV-visible and fluorescence spectroscopy, circular dichroism (CD) spectroscopy, electrochemical analysis, and mass spectrometry. These synthetic guidelines will then be applied to bimetallic chiral metal clusters to study the effects of cooperative interactions in model asymmetric transformations. Ultimately, the design rules generated from this research may be broadly applied to other classes of heterogeneous nanomaterials to understand and tailor their asymmetric catalytic properties with atomic precision.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.