HYDROGEN-BONDING INTERACTIONS IN THE 2,2'-BIPYRIDINE-PYROMELLITIC ACID COMPLEX - IR, NUCLEAR-MAGNETIC-RESONANCE AND THEORETICAL-STUDIES

The stability of the complex formed between 2,2'-bipyridine and pyrome llitic acid (1,2,4,5-benzenetetracarboxylic acid) in gaseous, liquid a nd solid state has been studied by using experimental and theoretical methods. The complex has been shown to be stable in gaseous and solid states, while in solution interactions via new hydrogen bonds occurred between 2,2'-bipyridine or pyromellitic acid and solvent molecules. S tructural parameters and interaction energies of such new hydrogen bon ded complexes determined by quantum chemical calculations have substan tiated the experimental observations. Correlations have been found bet ween the hydroxy proton chemical shifts and calculated association ene rgies and between carbon chemical shifts and the change in p character of the carboxyl carbon.