Properties and reactivity of chlorovinylcobalamin and vinylcobalamin and their implications for vitamin B12-catalyzed reductive dechlorination of chlorinated alkenes.
Vitamin B12-catalyzed reductive dechlorination of perchloroethylene (PCE) and trichloroethylene (TCE) is a potential strategy for cleanup of polluted environments. Presented are crystal structures of vinylcobalamin 2 and cis-chlorovinylcobalamin 1. They show a strong resistance toward photolysis. Reduction of 2 is difficult, but reduction of 1 occurs readily and produces 2. The mechanism of this latter reaction involves acetylene as an intermediate. These and other findings are discussed in the context of environmental studies on B12-catalyzed dechlorination of PCE and TCE and investigations of the haloalkene reductive dehalogenases that catalyze similar reactions.
McCauley
Kevin M
KM
Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois, USA.
Pratt
Derek A
DA
Wilson
Scott R
SR
Shey
Justin
J
Burkey
Theodore J
TJ
van der Donk
Wilfred A
WA
D000475:Alkenes / Q000737:chemistry*; D002384:Catalysis; D003035:Cobalt / Q000737:chemistry; D004563:Electrochemistry; D006843:Hydrocarbons, Chlorinated / Q000737:chemistry*; D008958:Models, Molecular; D010782:Photolysis; D013053:Spectrophotometry; D013750:Tetrachloroethylene / Q000737:chemistry; D014241:Trichloroethylene / Q000737:chemistry; D014753:Vinyl Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D014805:Vitamin B 12 / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry*
D000475:Alkenes; D006843:Hydrocarbons, Chlorinated; D014753:Vinyl Compounds; C474538:chlorovinylcobalamin; D014241:Trichloroethylene; D003035:Cobalt; D014805:Vitamin B 12; D013750:Tetrachloroethylene