Homoconjugation formation constant

During the conductometric measurements it was also observed that for various acids the equivalent conductivity became constant at higher concentrations, which can be explained67 by the formation of their homoconjugate ions HX2 = X" H+ X" for a number of acids we estimated by means of the method of French and Roe68 the formation constants concerned ... 

Consolidation of (4-93) and (4-94) to solve for [SH2 ] yields a complex expression. Therefore the numerical values of analytical concentrations of salt Cbha initial base Cb along with the formation constant for the homoconjugate complex are inserted in (4-94), and [B] is obtained at a specified point in a titration. This value of [B] is substituted in (4-93) to obtain [SH2 ]. Fortunately, the activity coefficients drop out in this method oFcalculating hydrogen ion concentration. 

We now discuss the related series wherein there are three double bonds or cyclopropanes. How does homoconjugation involving cyclopropanes compare to conjugation involving olefins Paralleling the nearly constant 57 kJmol" difference between the enthalpies of formation of ethylene (1, X = H) and butadiene (5), and butadiene (5) and ( )-hexatriene (6b), the first related difference of cyclopropane (2, X = H) and bicyclopropyl (8) is (75.8 3.6) kJmol We lack the enthalpy of formation data of either cis- or ra 5 -l,L 2, l"-tercycIopropyl (9a or 9b) and so the second related difference cannot be found directly from experimental measurements. However, the enthalpies of formation of their I -methyl derivatives have been reported" 34a = cw(l), (134.1 1.2), cw(g), 181.0 trans( ), (131.9 1.2), 34b = trans, 179.2 kJ mol. The first approximation of the enthalpy of formation assumes the change of enthalpies of formation upon demethylation... 

---