Multielectron transfer at heme-functionalized nanocrystalline TiO2: reductive dechlorination of DDT and CCl4 forms stable carbene compounds.
Hemin (chloro(protoporhyrinato)iron(III)) was found to bind to mesoporous nanocrystalline (anatase) TiO2 thin films from dimethyl sulfoxide solution, Keq=10(5) M-1 at 298 K. Band gap illumination in methanol reduced hemin to heme and led to the appearance of TiO2 electrons, heme/TiO2(e-). Reactions of heme/TiO2(e-) with CCl4 or 1,1-bis(p-chlorophenyl)-2,2,2-trichloroethane (DDT) led to the formation of stable carbene products in greater than 60% yield. The spectroscopic data are fully consistent with a dissociative two-electron organohalide reduction mechanism of CCl4 and DDT to yield (protoporhyrinato)FeIICCl2 and (protoporhyrinato)FeIIC=C(p-Cl-phenyl)2 respectively.
Stromberg
Jonathan R
JR
Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, USA.
Wnuk
Joshua D
JD
Pinlac
Rachelle Ann F
RA
Meyer
Gerald J
GJ
D002251:Carbon Tetrachloride / Q000737:chemistry*; D002713:Chlorine / Q000737:chemistry* / Q000302:isolation & purification; D003460:Crystallization / Q000379:methods*; D003634:DDT / Q000737:chemistry* / Q000302:isolation & purification; D004579:Electron Transport; D006418:Heme / Q000737:chemistry*; D008422:Materials Testing; D049329:Nanostructures / Q000737:chemistry*; D010084:Oxidation-Reduction; D017785:Photons; D014025:Titanium / Q000737:chemistry*
C009495:titanium dioxide; D006418:Heme; D002713:Chlorine; D003634:DDT; D002251:Carbon Tetrachloride; D014025:Titanium