Intramolecular hydrogen bonds in 2-iminoacetic acid and its derivatives - DFT calculations and 'Atoms in Molecules' analysis

DFT calculations were performed for 2-iminoacetic acid and its derivatives. B3LYP/6-311++G(d,p) results show that conformers of these species containing the five-membered ring closured by intramolecular O-H⋯N hydrogen bonding are stable and they correspond to energetic minima. The 'Atoms in Molecules' theory was also applied to characterize these interactions. Numerous correlations were detected between geometrical, energetic and topological parameters. The substituent effect was also analyzed and it was found that the strongest hydrogen bonds exist for Li and Na substituents while the weakest ones for F and Cl substituents.