Variable-temperature kinetics allow the determination of ΔH‡ vs ΔS‡ in a single experiment. Multiple variable-temperature data sets for the thermal isomerization of cis-azobenzene show an apparent isokinetic relationship, but this is due only to the mathematical correlation between ΔH‡ vs ΔS‡; the magnitude of the effect is almost identical to that observed for the thermal isomerization of a series of ortho-alkylated azobenzenes.
References
1.
ExnerO., Progr. Phys. Org. Chem., 1973, 10, 411.
2.
LefflerJ.E., J. Org. Chem., 1955, 20, 1202; J.E. Leffler and E. Grunwald, “Rates and equilibria of organic reactions“, Wiley, New York, 1963, Chap 9.
