Enaminones (enamines of β-dicarbonyl compounds) belongs to a group of organic molecules with interesting biological and farmaceutical properties, and might exist in three tautomeric forms, with the possibility of forming intra- and intermolecular hydrogen bonds. Detailed structural characterization of this group of organic molecules is needed to establish structure acitivity ralationships with special emphasis on hydrogen bonding. In this doctoral thesis structures of pentane-2,4-dione and 1-phenyl-but-2-en-1-one derivatives has been determined in solution, by using different spectroscopic (one and two dimensional NMR spectroscopy, UV, IR and Raman spectroscopy) and computational methods. Special attention has been devoted to the influence of the substituents (2-amino-3- nitrophenol i derivatives of 2-amino-2-methylphenols), nature of the solvent (different polarity and different proton-donor and proton-acceptor abbilites) and temperature on hydrogen bonding (intra- and intermolecular) structure of pentane-2,4-dione and 1-phenylbut-2-en-1-one derivatives. The experimental results were complemented with those obtained by computational methods, performed at the semiempirical PM6 level and by using density functional theory (DFT). Hydrogen bonding were characterized in vacuum, chloroforme and dimethyl sulfoxide (DMSO). All investigated pentane-2,4-dione and 1-phenyl-but-2-en-1-one derivatives have been found to exist in the ketoamine form in solution, irrespective of the solvent and the temperature. Results showed presence of strong intramolecular hydrogen bonds of the N– H ...O type as well as weaker intermolecular interactions between two molecules or between the molecule and the solvent.