Absolute rate constants for iminyl radical reactions

摘要

The kinetics of cyclization of the 2-methyl-6,6-diphenyl-5-hexeniminyl radical (3) were measured by laser flash photolysis methods from 0 to 50 deg C, and the kinetics of trapping of radical 3 by thiophenol and p-chorothiophenol were determined between 4 and 83 deg C by indirect methods using the unimolecular rate constants as the basis values. Radical 3 cyclizes with a rate constant of 2.2 x10~6 s~1 at 25 deg C and reacts with thiophenol and p-chlorothiophenol at this temperature with rate constants of 0.6 and 1.4x10~7 M~1 s~1, respectively.