ELECTRONIC AND VIBRATIONAL SPECTROSCOPY OF PHOTOTAUTOMERIZING HETEROAZAAROMATICS WITH INTRAMOLECULAR HYDROGEN-BONDS

Four phototautomerizing derivatives of bipyridyl with intramolecular s ingle and double hydrogen bonds are studied by IR and electronic spect roscopy. A broad TR band corresponding to the stretching vibration of the OH group engaged in the N ... HO hydrogen bond is observed in all compounds in solutions, KBr tablets and low-temperature Ar matrices. V ariations of excited state behaviour observed among the four molecules are well correlated with the ground state hydrogen bonding characteri stics.