Developing homogeneous catalytic systems for aerobic oxidative methylation with methane

在化学系化学催化项目的资助下，马里兰大学帕克分校的Andrei Vedernikov博士正在开发新型铂催化剂，将天然气中的甲烷转化为高附加值的化学品。空气中的氧气被用作反应物，因此这些反应避免了昂贵和潜在有毒的试剂。水是主要的反应副产物，因此产生的废物很少。甲烷以其化学惰性而闻名，开发更环保的工艺，使其在经济上可行地转化为高附加值产品，是一项根本性的化学挑战。为了解决这个问题，Vedernikov博士正在研究新型铂催化剂并设计新的催化剂。他利用理论和计算化学来探索合理的反应途径，并指导他的催化剂设计和实验工作。Vedernikov博士正在帮助来自低收入家庭的高中生。这些学生对化学感兴趣，并已被美国化学会华盛顿当地分会（ACS项目SEED）选中。学生们在他的实验室实习，为这个项目的实验工作做出了贡献。Vedernikov博士正在研究希洛夫型体系，其中使用O2作为氧化剂生成亲电性Pt(IV)Me中间体。在这项工作中使用了两种互补的实验方法。一种依赖于氧化还原介质的使用，例如Cu(II)，而另一种利用Pt(II)R中间体的配体激活O2。亲电的Pt(IV)R中间体随后被各种亲核试剂（羧酸、胺等）拦截，形成碳氢化合物衍生物，如季铵盐或酯，防止进一步氧化。Vedernikov博士正在对Pt（II）中心的配体环境如何激活和调节其对碳氢化合物C-H键和O2的反应性以产生Pt(IV)R中间体进行基本的机制理解。这两种方法的可行性最近在维德尔尼科夫博士的小组中得到了证明。密度泛函理论被用来指导这些新系统的设计并进行机理分析。开发更高效、更环保的甲烷功能化方案具有变革性。作为更广泛影响的一部分，维捷尔尼科夫博士正在与当地的高中生、本科生和研究生合作并培训他们参与这个项目。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

With funding from the Chemical Catalysis Program of the Division of Chemistry, Dr. Andrei Vedernikov of the University of Maryland College Park is developing novel platinum catalysts that convert methane from natural gas to high value-added chemicals. Oxygen from the air is used as a reactant and so these reactions avoid expensive and potentially toxic reagents Water is the major reaction by-product, so there is little waste produced. Methane is known for its chemical inertness and the development of greener processes for its economically-viable conversion to high-value added products is a fundamental chemical challenge. To tackle this problem, Dr. Vedernikov is studying novel platinum catalysts and designing new catalysts. He is taking advantage of theoretical and computational chemistry to explore plausible reaction pathways and guide his catalyst designs and experimental work. Dr. Vedernikov is working with high school students from low-income families. These students are interested in chemistry and have been selected by the local Washington D.C. section of the American Chemical Society (ACS Project SEED). The students intern in his lab, contributing to the experimental work in this project. Dr. Vedernikov is studying Shilov-type systems wherein electrophilic Pt(IV)Me intermediates are generated using O2 as the oxidant. Two complementary experimental approaches are used in this work. One relies on the use of redox mediators, e.g., Cu(II), while another utilizes a ligand-enabled O2 activation by Pt(II)R intermediates. The electrophilic Pt(IV)R intermediates are then intercepted by various nucleophiles (carboxylic acids, amines, etc.) to form hydrocarbon derivatives, such as quaternary ammonium salts or esters, that are protected from further oxidation. Dr Vedernikov is developing a fundamental mechanistic understanding of how the ligand environment at the Pt(II) center enables and tunes its reactivity toward both the hydrocarbon C-H bonds, and O2 to generate the Pt(IV)R intermediates. The viability of both approaches has been recently demonstrated in Dr. Vedernikov's group. Density functional theory is being used to guide the design of these novel systems and to carry out mechanistic analyses. The development of more efficient and environmentally benign protocols for methane functionalization is transformative. As a part of the broader impacts, Dr. Vedernikov is working with and training local high school, undergraduate and graduate students in this project.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.