Kinetic parameters of the cyclization and decyclization reactions of nitrogen- and oxygen-containing radicals

The intersecting parabolas model is used to analyze experimental data for the following radical cyclization and decyclization reactions: RCH=CH(CH2)nN·R1 → cyclo-[NR1CH(CH2)n]C·HR, R(CH2)2OOCH2C·HR → cyclo-[RCHOCH2] + RCH2CH2O·, cyclo-[(CH2)nOOCHC· HR] → cyclo-[RCHOCH](CH2)nO·, cyclo-[(CH2)nOC·RO] → RC(O)O(CH2)n − 1C·H2, and cyclo-[(CH2)nCHO·] → CH(O)(CH2)n − 1C·H2. The activation energy of the thermally neutral reaction (Ee,0) is calculated for each class of reactions. Ee,0 depends on the electronegativity of the heteroatom Y of the reaction center C\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document} $$\underline \cdots$$ \end{document}C...Y, the force constants of the reacting bonds, and the strain energy of the ring formed. For the cyclization and decyclization of six-membered rings, the empirical relationship between the elongation of the reacting bonds in the transition state (re) and the difference in electronegativity (ΔEA) between the C and Y atoms (Y = C, N, O) has the form re × 1011, m = 3.83 − 0.0198(ΔEA, kJ/mol).