CAREER: SusChEM: Development of Manganese Hydrosilylation Catalysts for Silicone Curing

在这个由化学部化学催化计划资助的项目中，亚利桑那州立大学的Ryan Trovitch教授正在研究从丰富的金属（如锰）中制备催化剂的方法，该催化剂可用于制备有机硅聚合物。 聚合物是长链分子，它们的许多性质来自于链之间的缠结和相互作用。 聚合物已成为我们日常生活中无处不在的材料，影响着大多数行业，包括农业和食品、健康和安全以及交通运输。 半个多世纪以来，有机硅聚合物已用于各种消费品，包括隐形眼镜、软管和医疗植入物。广泛用于有机硅制备和固化的大多数催化剂基于贵金属，例如铂或铱，这些相对有毒的元素由于其在地壳中的丰度低而获得成本高。 用于有机硅制备的锰基催化剂的开发将有可能取代贵金属催化剂的使用，这将代表可持续化学的重大进步。 Trovitch教授还致力于提高学生和公众对绿色化学的熟悉程度。 他正在为当地高中生开发一个可持续发展讲习班，并将提供基于该计划的视频，以实现广泛传播。 作为绿色化学承诺的顾问委员会成员，他正在参与正在进行的举措，通过更新的课程和实验室经验，向本科生和研究生介绍可持续化学的高级主题。 特罗维奇教授还与凤凰城公共图书馆合作组织科学咖啡馆讨论。 在该项目中，亚利桑那州立大学的Ryan J. Trovitch教授正在开发可持续的锰硅氢加成催化剂，该催化剂将表现出与广泛使用的贵金属催化剂相当的活性和选择性。 相对于第二和第三行过渡金属，锰由于其参与单电子反应途径的倾向而在催化应用中仍然未得到充分利用。 最近的研究结果表明，多齿，氧化还原非无辜的螯合配体，使锰催化的羰基氢化硅烷化可逆地转移电子和部分解离整个催化。在这一发现的基础上，Trovitch教授正在研究锰催化氢化硅烷化反应的几个方面，包括锰烯烃氢化硅烷化催化剂，可以作为基于铂的催化剂的替代品，新型羰基氢化硅烷化途径，使聚酮与聚氢硅烷或聚氢硅氧烷交联，以及合成硅氧烷网络的分解硅烷化途径。 通过电子结构测定和机理研究，用于烯烃硅氢加成、羰基硅氢加成和氢化硅烷基化的高活性锰催化剂正在通过明智地修饰其配体框架而开发。 该项目的成功完成将改变现有的锰催化知识，同时揭示高密度氧化还原非无害螯合物利用的潜在优势。

In this project funded by the Chemical Catalysis Program of the Chemistry Division, Professor Ryan Trovitch of Arizona State University is studying ways to make catalysts from abundant metals, such as manganese, that can be used to prepare silicone polymers. Polymers are long chain molecules that derive many of their properties from the entanglements and interactions between the chains. Polymers have become ubiquitous materials in our daily lives, impacting most industries, including agriculture and food, health and safety, as well as transportation. For more than half a century, silicone polymers have been used in a variety of consumer products including contact lenses, flexible tubing, and medical implants. Most catalysts that are widely employed in silicone preparation and curing are based on precious metals such as platinum or iridium, relatively toxic elements that are costly to obtain due to their low abundance in the Earth's crust. The development of manganese-based catalysts for silicone preparation would have the potential to supplant precious metal catalyst use, which would represent a significant advance in sustainable chemistry. Professor Trovitch is also working to enhance student and public familiarity with green chemistry. He is developing a sustainability workshop for local high school students, and videos based upon this program will be made available to achieve broad dissemination. As an Advisory Board Member of the Green Chemistry Commitment, he is participating in ongoing initiatives to introduce undergraduate and graduate students to advanced topics in sustainable chemistry through updated coursework and laboratory experiences. Professor Trovitch is also organizing Science Cafe discussions in collaboration with the Phoenix Public Library. In this project, Prof. Ryan J. Trovitch of Arizona State University is developing sustainable manganese hydrosilylation catalysts that will exhibit comparable activity and selectivity to widely used precious metal catalysts. Relative to second and third row transition metals, manganese remains underutilized in catalytic applications due to its propensity to participate in one-electron reaction pathways. Recent results have shown that polydentate, redox non-innocent chelate ligands enable manganese-catalyzed carbonyl hydrosilylation by reversibly transferring electrons and partially dissociating throughout catalysis. Building on this discovery, Professor Trovitch is studying several aspects of manganese-catalyzed hydrosilylation reactions including manganese olefin hydrosilylation catalysts that can serve as replacements for ones based upon platinum, novel carbonyl hydrosilylation pathways to crosslink polyones with polyhydrosilanes or polyhydrosiloxanes, and dehydrogenative silylation pathways to the synthesis of siloxane networks. Via electronic structure determinations and mechanistic studies, highly active manganese catalysts for olefin hydrosilylation, carbonyl hydrosilylation, and dehydrogenative silylation are being developed by judiciously modifying their ligand frameworks. Successful completion of this project will transform current knowledge of manganese catalysis while revealing potential advantages of high-denticity redox non-innocent chelate utilization.