Small Molecule Activation and Homogeneous Catalysis with Organometallic Molecules Based on Sustainable Transition Metals

化学转化的催化作用是化学工业对现代社会作出重大贡献的基石。绝大多数化学产品的生产都需要能够提高转化速度和选择性而又不会在转化过程中耗尽的催化模式实体。因此，催化领域的创新一直是加拿大人享受高生活水平的关键因素。催化技术的发展对人类社会的未来也是至关重要的。人类面临的重大能源和环境挑战将主要通过催化技术的进步来克服。具体地说，对能量不利的反应的选择性和快速催化仍然是该领域的一个挑战。在这类反应中，最重要的是小分子的活化和转化，这些小分子是燃烧(H2O、CO2)或氮气循环(N2)的最终产物。这些工艺产生的副产品和污染物(CH4、N2O)的转化也是最重要的。发现基于过渡金属的分子催化剂，能够将这些和其他小分子转化为有用的产品，如燃料或增值化学品，是该研究计划的首要目标。由于大规模地进行这些反应对解决环境和能源问题产生影响，第二个目标是开发利用地球上丰富的金属，如铁、镍和钴的催化剂。作为合成化学家，我们小组的方法是设计和合成过渡金属(TM)络合物的新配体，这些配体将成为此类转化的活性催化剂。“配体”是一种有机分子，它与TM结合，既塑造了金属周围的空间，又调节了它结合和激活小分子的能力。理想的配体设计特征包括：多密度(与中心金属的3-5个接触点)，鼓励形成高氧化态中间体的电子丰度，允许在多电子反应中管理电子的圆周率共轭，以及允许管理质子的中心TM附近的酸和碱位。我们结合这些特征创建配体，然后探索它们在TMS上的配位化学，并评估这些化合物作为上述反应催化剂的性能。该提案描述了我们团队的具体科学方法，重点是具有上述特征的两个最近开发的配体家族，以及针对新型TM配位环境和催化剂的令人兴奋的新配体设计。由Warren Piers博士领导的8-10名研究人员团队将探索这些重要问题，获得技术专业知识、沟通技能和解决问题的能力，使他们成为未来的创新者。

The catalysis of chemical transformations is the cornerstone of the chemical industry's major contribution to modern society. Catalystschemical entities that increase the rate and selectivity of a transformation without being used up in the processare needed for the manufacture of the vast majority of chemical products. Innovation in catalysis has thus been a key contributor to the high standard of living enjoyed by Canadians. Developments in catalysis are also essential for the future of human society. The significant energy and environmental challenges humanity faces will be surmounted primarily through technological advances in catalysis. Specifically, the selective and rapid catalysis of reactions that are energetically unfavorable remains a challenge for the field. Most important among such reactions involve the activation and conversion of the small molecules that are the end products of combustion (H2O, CO2) or the nitrogen cycle (N2). Conversion of by-products and pollutants derived from these processes (CH4, N2O) is also of prime interest. The discovery of molecular catalysts based on transition metals that are capable of converting these and other small molecules into useful products such as fuels or value added chemicals is an overarching objective of this research program. Since carrying out these reactions at the large scale necessary to have an impact in solving environmental and energy problems, a second objective is to develop catalysts that utilize the earth abundant metals like iron, nickel and cobalt.As synthetic chemists, our group's approach is to design and synthesize new ligands for transition metal (TM) complexes that will be active catalysts for such transformations. A “ligand” is an organic molecule that binds to the TM and both shapes the space around the metal and tunes its ability to bind and activate small molecules. Desirable ligand design features include the following: multidenticity (3-5 points of contact with the central metal), electron richness to encourage formation of high oxidation state intermediates, pi conjugation to allow for the management of electrons in multielectron reactions, and acid and base sites proximal to the central TM to allow for the management of protons. We create ligands with a combination of these features and then explore their coordination chemistry on TMs and evaluate the performance of these compounds as catalysts for the above mentioned reactions.The proposal describes our group's specific scientific approach, which focuses on 2 recently developed families of ligands with the above features, as well as exciting new ligand designs for novel TM coordination environments and catalysis.A team of 8-10 researchers, led by Dr. Warren Piers, will explore these important questions, gaining technical expertise, communication skills and problem solving abilities that equip them to be innovators of tomorrow.