Influence of Steric and Electronic Effects on the Binding of Arenediazonium Cations to 18-Crown-6 in Methanol at 25 deg C

Article abstract of DOI:10.1021/ja00529a027

Log K, ΔH, and TΔS values for the interaction of several arenediazonium salts with 18-crown-6 were determined in methanol at 25 deg C by the calorimetric titration technique.The complex of benzenediazonium cation with 18-crown-6 is enthalpy stabilized with log K = 2.50.Substitution of a methyl group onto the ortho position(s) of benzenediazonium cation results in a total loss of complex stability.Substitution of various groups onto the para position results in changes in complex stability according to the electronic effect exerted in the diazonium moiety.A linear Hammett relationship (ρ = 0.65) was found between log K and ?⁺_p values associated with the para substituent.