59527-14-9Relevant articles and documents
Polar Effects in Addition Reactions of Benzenethiyl Radicals to Substituted Styrenes and α-Methylstyrenes Determined by Flash Photolysis
Ito, Osamu,Matsuda, Minoru
, p. 1701 - 1703 (1982)
The absolute rate constants for the addition reactions of the benzenethiyl radical and its para-chloro derivative to para- and meta-substituted styrenes and α-methylstyrenes have been determined by the flash photolysis technique.The rate constants in the range of ca. 107-108 M-1 s-1 have been obtained.From the linear relationships in the Hammett plots vs. ?+, the reaction constants (ρ+) of C6H5S. toward substituted styrenes and α-methylstyrenes were estimated to be -0.26 and -0.30, respectively.The latter ρ+ value is compatible with the value estimated from the relative reactivities (-0.38).The polar effects of p-ClC6H4S. toward styrenes (ρ+ = -0.56) and α-methylstyrenes (ρ+ = -0.63) are larger that those of C6H4S..The sign and magnitudes of these ρ+ values are rationally interpreted in terms of the contribution of such polar resonance structure as -, CH2=C(R)C6H4Y+.> to the transition state.