CRAEMS: Environmental Redox-Mediated Dehalogenation Chemistry

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This Collaborative Research Activities in Environmental Molecular Science (CRAEMS) Award to Johns Hopkins University is supported by the Special Projects Office of the Chemistry Division. The award supports studies by Gerald Meyer, Howard Fairbrother, David Goldberg, Kenneth Karlin and A. Lynn Roberts of dehalogenation chemistry by combining their expertise in synthesis, homogeneous and heterogeneous catalysis, biomimetic and bioinorganic chemistry, electrochemistry, surface science, and environmental chemistry. Specific goals of this multidisciplinary program are: 1) the development of new reductive and oxidative dehalogenation chemistries and the elucidation of their fundamental mechanisms; 2) application of these new findings to the sensing, remediation, and determination of the environmental fate of organohalide pollutants; and 3) provide a pedagogical platform that informs and educates the next generation of environmental chemists. The fundamental studies will emphasize oxidative and reductive cleavage of organohalides by copper (I) and metalloporphyrin complexes. Both stoichiometric and electrocatalytic processes will be studied. Photo-triggered and electrochemical dehalogenation will also be examined. Dehalogenation by bimetallic reductants and metal sulfide minerals will be explored. Finally, electron-beam-induced chlorocarbon reductive cleavage will be examined in water and ice media. Collaborations include those with two National Laboratories (Oak Ridge National Laboratory and Pacific Northwest National Laboratory) and with two industries (KDF Fluid Treatment Inc., and Environmental Technologies Group Inc.). To develop an understanding of environmental principles and processes at the molecular level, a new graduate course will be developed and taught. An outreach program involving underrepresented undergraduate researchers from nearby universities (Howard University and Morgan State University) will be implemented.Seventeen of the top twenty-five organic pollutants in the U.S. are organohalides. Volatile organohalides also deplete ozone and change global climate. This interdisciplinary work aims at a molecular-level understanding of redox-mediated dehalogenation, from which "greener" chemical processes can be developed and pollution problems due to organic halides can be obviated. The educational aspects of this multidisciplinary program, in collaboration with government laboratories and industries, is designed to increase the awareness of students concerning real-world environmental problems and to provide hands-on experience.