INFRARED STUDY OF THE HYDROGEN-BOND COMPLEXES INVOLVING 2,3-BIS-(2-PYRIDYL)-PYZAZINE AND PROTON DONORS - COMPARISON WITH MONOFUNCTIONAL HETEROCYCLIC N-BASES

The hydrogen bond complexes between phenols and 2,3-bis(2-pyridyl)-pyr azine BPP) are investigated by infrared spectroscopy in carbon tetrach loride solution. The formation constants for the complexes of 1-1 stoi chiometry are higher than those predicted from the pK(a) of BPP. This is also the case for other N-heteroaromatic bases (Pyridazine, 2,2'-bi pyrimidine) characterized by two vicinal equivalent nitrogen atoms. Th e thermodynamic and infrared data of the complexes show that BPP canno t be considered as a proton sponge.