NMR study of hetero-association accompanying self-association of 2-hydroxyl-4-methyl-pyridine and 2-pyrrolidone in acetonitrile

This work investigated not only the equilibrium of self-association of 2-py rrolidone (A) and that of 2-hydroxyl-4-methyl-pyridine (B), but also the he tero-association between A and B in [H-2(3)]acetonitrile through hydrogen b onding using high-resolution nuclear magnetic resonance spectroscopy. Dilut ion shift data for the protons of the NW group of A and OH group of B were measured over a wide range of temperatures and concentrations. In addition, the monomer shifts, dimer shifts and dimerization constants of self-associ ation and hetero-association were evaluated using a graphic method operatin g on the dilution chemical shift data. The enthalpy and entropy of dimeriza tion of self-association and hetero-association were also obtained from the van't Hoff plot.