CAS: Synthetic Entries to ETM with M-Ligand Multiple Bonds and Their Role in Stoichiometric and Catalytic Carbon-Hydrogen Activation and Functionalization of Volatile Alkanes

在化学系化学合成（SYN）项目的支持下，宾夕法尼亚大学的Daniel J. Mindiola教授将研究最丰富和最易挥发的碳氢化合物（如甲烷、乙烷和丙烷）在温和条件下零二氧化碳排放的基本反应性。该项目将制定新的战略，利用钛、钒、铌等地球上丰富的贱金属，将甲烷和乙烷等自然资源（天然气和页岩气的主要成分）转化为附加值更高的材料。一个主要目标是将这些烷烃转化为烯烃；分子是工业的基石，因为它们用于设计聚合物、粘合剂、洗涤剂和许多其他增值化学品，这些化学品通常在商业和家庭中使用。由于其易挥发性和有限的可用存储容量，这些自然资源经常以惊人的速度燃烧，因此它们的燃烧以及它们直接释放到我们的大气中，在我们脆弱的环境中起着巨大的作用。我们的主要目标是使用含有高极性金属-碳或金属-氮多键的化合物选择性地和可控地激活这些烷烃，特别是在温和的条件下（室温），这与在能源密集型条件下倾向于裂解这些烷烃的工业过程形成对比。该研究还将探索构建明确的金属氧化物、硫化物或较重的硫族化物（Se和Te）类似物的方法，并将这些类似物用作其他金属离子的支撑物，以模拟金属氧化物支撑物如何与金属催化剂一起使用。Mindiola博士活跃于ACS（美国化学学会）和ACS学者计划近20年，以促进物理科学的多样性。他积极参与在大学和全国中小学推广甲烷和其他“神秘”碳氢化合物的科学。他的研究小组还将开发播客，解释他们的研究项目，但目标受众更广泛。这些由学生和博士后同事组织的短片将通过YouTube群组频道“mindisence”向公众提供，目的是向社区宣传燃烧、催化、天然和页岩气及其丰富的化学成分。Mindiola研究小组将研究由Ti、V和Nb组成的早期过渡金属离子的化学性质，以及这些离子如何在温和的条件下选择性地促进挥发性碳氢化合物脱氢，形成末端含有这些不饱和的烯烃。PI的研究小组将通过开发金属-碳、氮、磷和硫的多重键，以及它们与烷烃的反应性来研究这些反应。结合合成、反应性和机理研究，宾大团队将探索使用这些贱金属配合物实现更高催化转化率的优化条件。一个特定的反应是利用一种定义明确的金属配合物将甲烷在室温下转化为烯烃，这种配合物可以将母体碳氢化合物脱氢成类似施洛克的母体碳氢化合物。Mindeola及其同事还计划合成第4族过渡金属双硫族化合物和杂金属化合物的原型。如果成功，这种化学反应预计将在生产有价值的烯烃构建块方面产生实际影响，并为可持续化学做出重要贡献。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 the support of the Chemical Synthesis (SYN) program in the Division of Chemistry, Professor Daniel J. Mindiola of the University of Pennsylvania will study the fundamental reactivity of the most abundant and volatile hydrocarbons such as methane, ethane, and propane under mild conditions and with zero emission of carbon dioxide. The project will establish new strategies to convert natural resources such as methane and ethane, the main components of natural and shale gases, into more value-added materials using earth-abundant base metals such as titanium, vanadium, and niobium, among others. One main target is to convert these alkanes into olefins; molecules that are industrial building blocks due to their use in the design of polymers, adhesives, detergents, and many other value-added chemicals that are routinely used commercially and in the household. Because of their volatility and limited storage capacity available, these natural resources are routinely being flared at staggering rates, so their combustion as well as their direct release into our atmosphere play a tremendous role in our fragile environment. Our main objective will be to selectively and controllably activate these alkanes using compounds that contain highly polar metal-carbon or metal-nitrogen multiple bonds, especially under mild conditions (room temperature), which is in contrast to industrial processes that tend to crack these alkanes under energy-intensive conditions. The research will also explore methods to construct well-defined metal-oxide, -sulfide or heavier chalcogenide (Se and Te) analogues, and to use these as supports for other metals ions to mimic how metal-oxide supports are used in conjunction with metal catalysts. Dr. Mindiola has been active with the ACS (American Chemical Society) and the ACS Scholars Program for nearly 20 years in order to promote diversity in the physical sciences. He is actively involved in promoting the science of methane and other “mysterious” hydrocarbons at the university level as well as in elementary and middle schools nationwide. His research group will also develop podcasts explaining their research projects but aimed to a broader audience. These short clips organized by students and postdoctoral associates will be available to the public through the YouTube group channel “MindiScience” with the aim to educate the community about flaring, catalysis, natural and shale gases, and their rich chemistry. The Mindiola research team will study the chemistry of early-transition metals ions composed of Ti, V, and Nb, and how these can promote the dehydrogenation of volatile hydrocarbons, selectively and under mild conditions, into olefins containing these unsaturation at the terminal positions. The PI’s research team will investigate these reactions via the development of metal-carbon, nitrogen, phosphorus, and chalcogen multiple bonds, and their reactivity with the alkanes. Using a combination of synthesis, reactivity, and mechanistic studies, the Penn team will explore optimized conditions for higher catalytic turnover using these base metal complexes. One specific reaction being targeted is the room temperature conversion of methane into an olefin using a well-defined metal complexes that can dehydrogenate the parent hydrocarbon into a parent Schrock-like carbene. Mindeola and co-workers also plan to synthesize archetypes of group 4 transition metal bischalcogenides and heterobimetallics. If successful, such chemistry is expected to have both real practical impact in making available valuable olefin building blocks and in providing an important contribution to sustainable chemistry.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.