Infrared spectroscopic studies of hydrogen bonding in triethylammonium salts. Part 4.—Rearrangement of hydrogen-bonded ion pairs of triethylammonium salts caused by interaction with tetrabutylammonium salts in solution

Abstract

Rearrangement of triethyl-and tetrabutyl-ammonium salts in chloroform solution has been revealed from the characteristic features of the ν(N⁺H) bands caused by Fermi resonance interaction. Temperature changes of the i.r. spectra show this process to be reversible. Rearrangement constants K₁ and K_–1 and enthalpies –ΔH(for some cases only) of this process have been determined by measuring the total integrated intensities of the ν(N⁺H) bands of complexes which are in equilibrium. K₁ values of the tetrabutylammonium salts increase with decreasing hydrogen bonding strength in triethylammonium salts. The measured enthalpies of rearrangement and those calculated from the ν(N⁺H) bands of hydrogen-bonded complexes studied are in agreement. It has also been shown that tetrabutylammonium salt anions can participate in the rearrangement of hydrogen-bonded ion pairs like the organic bases studied previously.