RUI: CAS: Production of Highly Reactive Metal-Oxo Species with Molecular Oxygen and Visible Light for the Selective Oxidative Catalysis

Western Kentucky University, Bowling Green KY

Investigators

Abstract

With the support of the Chemical Catalysis Program in the Division of Chemistry, Professor Rui Zhang of Western Kentucky University (WKU) will study the reaction of organic compounds with oxygen from the atmosphere using catalysts, in a process called catalytic aerobic oxidation. This process is widely used daily on a large scale for the production of valuable chemicals, the environmental remediation of pollutants, and in the production of energy. Dr. Rui Zhang and his students at WKU are working to develop bio-inspired photocatalysts that can utilize sunlight to activate and incorporate atmospheric oxygen into inexpensive materials for producing high-value commodity chemicals. The use of abundant solar energy and atmospheric oxygen rather than a chemical reagent in the oxidation of bulk chemicals generates less chemical waste, is more chemically sustainable, and potentially reduces the economic costs associated with the process. The research will impact the fundamental science and technology of green chemistry. In addition, this project will provide cutting-edge research experiences for the participating undergraduate students, including underserved students and women in science, technology, engineering, and mathematics (STEM) disciplines, thereby training future STEM professionals. High school students from the nationally renowned Gatton Academy, the residential Math and Science Academy located on WKU’s campus, will also perform research in the laboratory and learn about catalysis research. In this research, Professor Rui Zhang and his team will study metal phthalocyanine complexes (MPc’s) as sustainable and “green” oxidation catalysts in view of their easy accessibility and outstanding redox and optical properties. This research will focus on mechanistic studies and the generation of metal-oxo oxidizing species involved in MPc-based catalysis, and will use the new knowledge obtained to develop viable and practical catalytic methods for clean oxidations. Although MPc’s are very attractive and are widely applicable catalysts in many oxidation processes, mechanistic aspects of MPc-catalyzed oxidations and identification of the MPc-based metal-oxo reactive intermediates are still underdeveloped. High-valent transition metal-oxo oxidants in different macrocyclic systems can be generated photochemically and used for oxidations through disproportionation reactions. In this project, Dr. Zhang and his students at WKU aim to explore new ways to probe the nature of active oxidizing species and elucidate mechanisms extant in MPc-mediated catalysis. Importantly, a variety of new MPc-based catalysts that contain photoabsorbed units will be synthesized and investigated for photocatalytic aerobic oxidations. This research is expected to advance knowledge in metal-oxo chemistry and photocatalysis and to have long term implications for the conversion of solar energy in catalysis. 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.