ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 26, Number 1
JKCSEZ 26(1)
February 20, 1982 

The addition of thiophenol to α-methylstyrene has been studied MO theoretically using CNDO/2 method. Although overall reaction proceeds in two steps i.e., (1) decomposition of thiophenol to give phenylthiyl radical and (2) addition of the radical to α-methylstyrene to give a new monomer radical, theoretical results suggested that the phenylthiyl radical formation step, (1), was the dominant process in determining the rate of addition; this was the rationale behind the negative ρ value obtained experimentally from the Hammett plots for substituents on the thiyl radicals. The departure from a linear Hammett plot for addition of p-chlorophenylthiyl and m-trifluoromethyl phenylthiyl to p-methoxy-α-methylstyrene could be explained as a result of an increased contribution of the addition step, (2) to the overall reaction rate.