Chlorinated ethylenes like tetrachloroethylene (PCE) and trichloroethylene (TCE) are used in the dry-cleaning and degreasing industries, and they have been found to be carcinogens. The cobalt-containing cobalamin cofactor found in reductive dehalogenases and the nickel-containing cofactor F430 found in methyl-coenzyme M reductase are both capable of dechlorinating PCE and TCE through a poorly-understood reaction mechanism. A thorough understanding of this reaction could lead to improvements in remediation strategies to treat these harmful pollutants. We are investigating this reaction using model compounds inspired by cobalamin and cofactor F430. In this work, we demonstrate that both [Ni(cyclam)]+ and [Ni(TMC)]+ (TMC = tetramethylcyclam) are capable of dehalogenating chlorinated ethylenes and can convert PCE to TCE. Compounds were characterized by elemental analysis and UV-visible spectroscopy. Reaction products were identified using solid-phase microextraction (SPME) in conjunction with gas chromatography-mass spectrometry. We report our efforts to optimize reaction conditions and to move toward catalytic activity. This work will benefit our understanding both of dechlorination reactions and of nickel bioinorganic compounds like cofactor F430.

Investigating dechlorination using bio-inspired nickel compounds

253rd National Meeting (2017)

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