3248-58-6Relevant articles and documents
Effect of fluorination on thiol reactivities. Reaction of 2,2,2-trifluoroethanethiol on Mo(110)
Napier,Friend
, p. 8750 - 8757 (1995)
The reactions of 2,2,2-trifluoroethanethiol on Mo(110) were studied using temperature-programmed reaction, Auger electron, and infrared spectroscopies. Most significant is the evolution at 265 K of tritluoroethyl radical from a saturation coverage of CF3CH2S-. The strong coverage dependence for trifluoroethyl radical evolution and models depicting trifluoroethyl thiolate orientation at saturation coverage strongly suggest that surface crowding plays a significant role in radical formation. The stability of the radical and the steric inhibition to finding an adsorption site explain the evolution of the radical into the gas phase. C-S bond hydrogenolysis, yielding trifluoroethane, and defluorination, yielding difluoroethylene, are of nearly equal importance in the reaction of trifluoroethyl thiolate, whereas C-S bond hydrogenolysis of ethyl thiolate to form ethane predominates. The C-S bond hydrogenolysis pathway is similar for the two thiols, occurring at approximately 300 K in both cases. Dehydrogenation and alkene elimination from CH3CH2S- occur at approximately 340 K, as the supply of surface hydrogen is depleted through hydrogen recombination. In contrast, defluorination and fluoroalkene elimination from CF3CH2S- occur over a wide temperature range, 200-520 K. The formation of difluoroethylene on Mo(110) is nearly thermoneutral, due to the comparable strengths of the C-F and Mo-F bonds and the stability of difluoroethylene.
Reaction of phenylchlorocarbene and diphenylcarbene with the carbon-chlorine bond: Kinetics and mechanisms
Jones, Michelle B.,Maloney, Vincent M.,Platz, Matthew S.
, p. 2163 - 2169 (2007/10/02)
The reactions of phenylchlorocarbene (PCC) and diphenylcarbene (DPC) with carbon-chlorine bonds were investigated by laser flash photolysis techniques, product studies, and electrochemical methods. The data with both carbenes are consistent with a polar chlorine atom transfer to form radical pairs. The PCC reaction can be thought of as an inner sphere electron transfer from the carbene to the carbon-halogen bond in which there is partial carbon-halogen bond formation in the transition state. The transition state is thought to involve a crossing between closed- and open-shell singlet surfaces. The data obtained in the reaction of DPC with chlorine donors resembles the data obtained with PCC but is more difficult to interpret because the multiplicity of the state reacting with the C-Cl bond is unclear.
