Earth Abundant Oxidation Catalysts for Removal of Contaminants of Emerging Concern from Wastewater: Homogeneous Catalytic Screening of Monomeric Complexes
Leslie Garcia,
Makynna R. Koper,
Somrita Mondal,
Joshua T. Priddle,
William A. Truong,
Elisabeth M. A. Allbritton,
Ashtyn G. McAdoo,
Desiray J. Cannon-Smith,
Neil L. Funwie,
Tuyet Hoang,
Inseo Kim,
David J. Hubin,
Jeanette A. Krause,
Allen G. Oliver,
Timothy J. Prior,
Timothy J. Hubin
Affiliations
Leslie Garcia
Department of Chemistry and Physics, Southwestern Oklahoma State University, Weatherford, OK 73096, USA
Makynna R. Koper
Department of Chemistry and Physics, Southwestern Oklahoma State University, Weatherford, OK 73096, USA
Somrita Mondal
Department of Chemistry and Physics, Southwestern Oklahoma State University, Weatherford, OK 73096, USA
Joshua T. Priddle
Department of Chemistry and Physics, Southwestern Oklahoma State University, Weatherford, OK 73096, USA
William A. Truong
Department of Chemistry and Physics, Southwestern Oklahoma State University, Weatherford, OK 73096, USA
Elisabeth M. A. Allbritton
Department of Chemistry and Physics, Southwestern Oklahoma State University, Weatherford, OK 73096, USA
Ashtyn G. McAdoo
Department of Chemistry and Physics, Southwestern Oklahoma State University, Weatherford, OK 73096, USA
Desiray J. Cannon-Smith
Department of Chemistry and Physics, Southwestern Oklahoma State University, Weatherford, OK 73096, USA
Neil L. Funwie
Department of Chemistry and Physics, Southwestern Oklahoma State University, Weatherford, OK 73096, USA
Tuyet Hoang
Department of Chemistry and Physics, Southwestern Oklahoma State University, Weatherford, OK 73096, USA
Inseo Kim
Department of Chemistry and Physics, Southwestern Oklahoma State University, Weatherford, OK 73096, USA
David J. Hubin
Department of Chemistry and Physics, Southwestern Oklahoma State University, Weatherford, OK 73096, USA
Jeanette A. Krause
Department of Chemistry, University of Cincinnati, Cincinnati, OH 45220, USA
Allen G. Oliver
Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA
Timothy J. Prior
Department of Chemistry, School of Natural Sciences, University of Hull, Kingston Upon Hull HU6 7RX, UK
Timothy J. Hubin
Department of Chemistry and Physics, Southwestern Oklahoma State University, Weatherford, OK 73096, USA
Twenty novel Mn, Fe, and Cu complexes of ethylene cross-bridged tetraazamacrocycles with potentially copolymerizable allyl and benzyl pendant arms were synthesized and characterized. Multiple X-ray crystal structures demonstrate the cis-folded pseudo-octahedral geometry forced by the rigidifying ethylene cross-bridge and show that two cis coordination cites are available for interaction with substrate and oxidant. The Cu complexes were used to determine kinetic stability under harsh acidic and high-temperature conditions, which revealed that the cyclam-based ligands provide superior stabilization with half-lives of many minutes or even hours in 5 M HCl at 50–90 °C. Cyclic voltammetry studies of the Fe and Mn complexes reveal reversible redox processes indicating stabilization of Fe2+/Fe3+ and Mn2+/Mn3+/Mn4+ oxidation states, indicating the likelihood of catalytic oxidation for these complexes. Finally, dye-bleaching experiments with methylene blue, methyl orange, and rhodamine B demonstrate efficient catalytic decolorization and allow selection of the most successful monomeric catalysts for copolymerization to produce future heterogeneous water purification materials.
