COMPUTATIONAL INVESTIGATION OF HYDROGEN-BONDED COMPLEXES USING AB INITIO METHODS

Аннотация

In this study, the vibrational characteristics of the C=O and N–H groups in the formamide molecule were investigated using density functional theory (DFT) at the B3LYP/6-311++G(2d,p) level of theory. In addition, the geometrical and optical properties of the molecular systems were analyzed. The theoretical results revealed that the C=O and N–H stretching vibrations of formamide undergo red shifts upon the formation of molecular aggregates. An increase in the water content of the system was found to enhance the stability and formation energy of these aggregates. The aggregates are stabilized by various types of hydrogen bonds. The calculations further demonstrated that, with increasing numbers of water molecules, hydrogen bonding occurs not only through conventional O–H···O interactions but also through O–H···N-type interactions. Furthermore, the electron density distributions and three-dimensional molecular electrostatic potential maps of the formamide–water systems were examined. These results provide deeper insight into the nature and energetics of intermolecular interactions in the aqueous environment of formamide.