Reactive Intermediates, Reaction Mechanisms, and Catalytic Cycles in the Gas Phase

Virginia Commonwealth University, Richmond VA

Investigators

Abstract

The Chemical Structure, Dynamics and Mechanism Program of the NSF Chemistry Division supports the research of Professor Scott Gronert in the Department of Chemistry at Virginia Commonwealth University. Professor Gronert and his students are developing and using novel gas-phase techniques to study catalytic reactions that are important in the synthesis and production of pharmaceuticals and other fine chemicals. Their methodologies involve converting mass spectrometers into gas-phase reactors, and allow them to probe individual steps in complex reaction processes, with the goal of finding ways to improve the efficiency and selectivity of current catalysts. Professor Gronert and his group are also using this technology to seek out new catalytic systems that have superior properties to those currently in use. Professor Gronert's research program is deeply engaged in training students at all levels and encourages undergraduates to participate in independent research projects early in their college careers. In addition, Professor Gronert recruits one student each summer from a local HBCU (historically black college or university) to participate in a research project. The exceptional versatility of modern mass spectrometry offers unique opportunities for studying reactive intermediates under highly-controlled conditions and probing their intrinsic reactivity. The Gronert group has converted ion-trap mass spectrometers into ion reactors and uses them to study gas-phase reaction kinetics and equilibria. A central focus of the research involves isolating and characterizing key reactive intermediates in important catalytic cycles. In this project, three systems involving ligated metal complexes are being investigated: (1) The scope of new phenanthroline-based iridium(III) C-H activation catalysts; (2) New, 2-electron reduction methodologies to generate potential intermediates in cobalt- and nickel-catalyzed C-C coupling reactions; and (3) New 1-electron reduction methodologies to generate transition metals in unusual oxidation states and characterize their roles in reaction processes. In addition, a variable temperature ion reactor are being used to examine enthalpy/entropy effects in templated, gas-phase reaction systems. The outreach plan is tightly integrated into the research and a key component involves recruiting students each year from a local historically black university, Virginia Union University.