Asymmetric Catalysis by Chiral-Polymer-Induced and Stabilized, Chiral-Surface Nanoclusters

0756633陈金宇。总体目标。该提案解决了催化领域的一个重大挑战：开发多金属、纳米簇“非均相”催化剂，以实现高ee催化不对称合成。新的螺旋手性聚合物将被合成，并利用其诱导和稳定手性表面纳米团簇的能力进行不对称催化。反过来，这些进步将推动对科学界及其所服务的行业具有重要意义的新型不对称催化剂的合理开发。此外，本文的研究将发现多金属不对称催化剂的关键原理和概念。本提案的具体目标是研究三个主要假设：(i)在专门设计的新型手性聚合物存在的情况下，Pt和Ir纳米团簇的成核和生长将使手性表面纳米团簇的诱导和稳定性优于迄今为止可能的，因为手性聚合物的纳米长度尺度与纳米团簇的纳米长度尺度的手性结位表面相匹配；（ii）已知的多金属偏好反应，如苯加氢催化，也在Pt和Ir纳米团簇中已知，可以扩展到纳米团簇前手性间烷基酚的不对称还原，作为多金属不对称催化的原型测试反应，这是有机群落及其服务的工业感兴趣的反应；（iii）手性催化剂的性质将是具有螺旋手性、扭结表面的惠滕型纳米团簇，目前，这是一种未被识别、未被研究、因此完全未开发的新型多金属不对称催化剂。NSF团队及其相关专业知识和实验方法。美国国家科学基金会（NSF）已经组建了一个团队，为这项大挑战提供所需的科学专业知识和物理方法：来自科罗拉多州立大学（CSU）的3名合作项目负责人，教授。E. Chen， R. Finke和T. Rovis，以及来自太平洋西北国家实验室（PNNL）的合作者J. Linehan博士和他的三位同事J. Fulton， W. Shaw博士和S. Kathmann博士。这个NSF团队的综合协同专业知识涵盖：纳米科学；材料、无机、有机和高分子化学；催化;不对称、纳米团簇和手性聚合物合成；动力学与机理；先进的operando表征方法；计算化学。所提议的研究的智力价值至少包括三个组成部分：首先，概述的研究将检查和利用在手性配体存在下生长纳米团簇的高概率，从而产生一类新的多金属、不对称的、固有的手性催化剂；其次，目前NSF的提案中前所未有的方面包括开发新的、功能化的手性螺旋聚合物，以更好地诱导和稳定手性表面纳米团簇，可用于催化重要的不对称反应；第三，概述的研究也将有望推进多金属纳米团簇催化剂表面位置的基础知识。该研究的广泛影响至少有4倍，包括其影响：(i)通过阐明多金属不对称催化的指导原则和概念来发现和理解这一非常及时的领域；（ii）通过将研究与教育相结合的方式进行教学、培训和学习，这些领域涵盖了现代化学科学家在解决当今广泛问题时所需要的大部分内容。此外，代表性不足的、多样化的和本科生将接受高级科学方法的训练，这种方法最好地发展了思考和分析的深度，这也是当今问题所需要的，即反驳多个可选假设；（iii）将发展网络和合作伙伴关系，以加强研究和教育的基础设施，特别是与国家实验室PNNL以及与科罗拉多州立大学合作的3个少数民族服务机构，科罗拉多州立大学普韦布洛分校，刘易斯堡学院和新墨西哥高地大学的合作伙伴关系；（iv）由于这项研究是在化学催化领域，对我们的现代生活方式至关重要，估计每年在全球范围内产生10万亿美元的经济影响，因此拟议的工作也将对社会产生广泛的影响。

0756633 Chen, Eugene Y. Overall Objectives. This proposal addresses a Grand Challenge of catalysis: the goal of developing polymetallic, nanocluster "heterogeneous" catalysts that can achieve high %ee catalytic asymmetric synthesis. Novel helical chiral polymers will be synthesized and exploited for their ability to induce, as well as stabilize, chiral-surface nanoclusters for asymmetric catalysis. Those advances will, in turn, fuel the rational development of new asymmetric catalysts of significance to the scientific community and the industries they service. In addition, the studies herein will discover key principles and concepts underlying polymetallic asymmetric catalysts.The Specific Objectives of this proposal are to investigate three dominant hypotheses: (i) that the nucleation and growth of Pt and Ir nanoclusters, in the presence of specifically designed novel chiral polymers, will allow both superior induction as well as better stabilization of chiral-surface nanoclusters than heretofore possible, due to the match of the nm length scale of the chiral polymer with the nm length scale of the nanocluster's chiral kink-site surface; (ii) that known polymetallic preferring reactions, such as benzene hydrogenation catalysis, that are also known in Pt and Ir nanoclusters, can be extended to nanocluster asymmetric reduction of prochiral meta-alkylphenols as a prototype test reaction of polymetallic asymmetric catalysis, a reaction of interest to the organic community and the industries that they service; and (iii) that the nature of the chiral catalyst will be nanoclusters with helically chiral, kink-site surfaces of the Whetten type that are, at present, an unrecognized, unstudied and thus completely undeveloped new class of polymetallic asymmetric catalysts.NSF Team and Its Associated Expertise and Experimental Methods. An NSF Team has been assembled with the required breadth of scientific expertise and physical methods for this Grand Challenge: 3 co-PIs from Colorado State University (CSU), Profs. E. Chen, R. Finke, and T. Rovis, and a collaborator from Pacific Northwest National Laboratories (PNNL), Dr. J. Linehan plus 3 of his colleagues J. Fulton, Dr. W. Shaw, and Dr. S. Kathmann. This NSF Team's combined synergistic expertise spans: nanoscience; materials, inorganic, organic and polymer chemistries; catalysis; asymmetric, nanocluster and chiral-polymer synthesis; kinetics and mechanism; advanced operando characterization methods; and computational chemistry.The Intellectual Merit of the proposed research consists of at least 3 components: first, the studies outlined will examine and exploit the high probability that growing nanoclusters in the presence of chiral ligands will yield a new class of polymetallic, asymmetric catalysts that are inherently chiral; second, unprecedented aspects of the present NSF proposal include the exploitation of novel, functionalized chiral helical polymers for both superior induction and better stabilization of chiral-surface nanoclusters that can be used to catalyze important asymmetric reactions; and third, the studies outlined will also promise to advance fundamental knowledge of the surface sites of polymetallic, nanocluster catalysts.The Broader Impacts of the research are at least 4 fold and include its impacts on: (i) discovery and understanding by elucidating the guiding principles and concepts underlying the very timely area of polymetallic asymmetric catalysis; (ii) teaching, training, and learning via an integration of research with education in areas which span much of what is required of a modern chemical scientist when addressing today's broad problems. Moreover, underrepresented, diversity, and undergraduate students will be trained in the superior scientific method which best develops the depth of thought and analysis also required by today's problems, namely the disproof of multiple alternative hypotheses; (iii) networks and partnerships will be developed which will enhance the infrastructure for research and education, notably the partnerships with a National Lab, PNNL, and with the 3 minority serving institutions that CSU partners with, CSU Pueblo, Fort Lewis College, and New Mexico Highlands University; and (iv) the proposed work will also achieve a broad impact on society since the research is in chemical catalysis, an area central to our modern way of life, one with an estimated economic impact of 10 trillion dollars per year worldwide.