The complexation and proton transfer equilibria and polarizability of phenol–tributylamine systems

Abstract

IR spectroscopic and dielectric studies on the complexation of tributylamine with 2,4,6-trichlorophenol, 2,4,6-tribromophenol and 2,4,6-triiodophenol in various solvents were performed with special emphasis on the stability and dipole moments of 1:1 and 2:1 (phenol:amine) adducts. The choice of such systems was conditioned by a sufficiently high proton donor ability of phenols and considerable diminution of self-association so that the complexation equilibria are practically limited to 1:1 and 2:1 species. Both the experimental results and ab initio calculations showed high stability of the proton transfer 2:1 species owing to the formation of homoconjugated (OHO)⁻ anions. The solvent effects, both macroscopic and specific, on the stability of and charge distribution in the adducts and thermodynamic parameters of the proton transfer processes in 1:1 adducts are discussed.