35Cl nuclear quadrupole resonance studies of pentachlorophenol–amine hydrogen-bonded complexes
Abstract
A series of hydrogen bonded complexes of pentachlorophenol with various N bases, covering a wide range of ΔpKa values, was investigated using 35Cl n.q.r. The average frequencies of 35Cl n.q.r. of these complexes were compared with those of pentachlorophenol, tetrabutylammonium pentachlorophenolate and tetrabutylammonium bis-pentachlorophenolate. The changes of average frequencies as a function of ΔpKa are very similar to the dipole moment changes with hydrogen bond formation as a function of ΔpKa, but in solids the range of inversion is shifted to lower ΔpKa values. The region in which the dielectric and spectroscopic anomalies are observed may be formally attributed to the existence of the proton transfer equilibrium.