Theoretical Researches On Binding Modes and Stability of Hydrogen Bonds Between Uracil and Formic Acid

Abstract

The hydrogen bond formation with formic acid would affect the complementary pair of bases between uracil and adenine, but the binding modes and spectral properties of hydrogen bonds are still obscure. Density functional theory and time-dependent density functional theory were applied to investigate the intermolecular hydrogen bonds between uracil and formic acid. The reduced density gradient (RDG), bond lengths and vibration absorption frequencies revealed that the most probable uracil-formic acid (U-FA) interaction mode formed in the position c of FA and the site 1 of U, that is, the mode 1c. The theoretical parameters in excited state complexes manifested that the variety of hydrogen bond configurations led to different degrees of strengthening or weakening of molecular interaction. In the implicit solvent (water), the formations of O-H∙∙∙O in the uracil-formic acid complexes were promoted obviously. These theoretical studies would positively affect the researches of life science and medicinal chemistry.

Comparison of the Molecular Properties of Euglobals Differing by the Mutual Positions of the Two R–C=O Groups (R = H and CH2CH(CH3)2): A Computational Study

“…Blueshifts are frequent for C-H bonds in which C has sp 2 hybridisation [67]. An increase in the frequency of the C-H stretching mode is mostly reported for the C-H bond of aldehyde groups [61,[67][68][69], and also for the C-H of formic acid, where the C to which the H is bonded is also part of a C=O group [70]. The presence of a blueshift in the C-H stretching frequency is viewed as an indicator of the presence of C-H•••O H-bonds because it would not occur without them [71]; for instance, it is a potential diagnostic of the presence of C-H•••O H-bonds within a protein [72].…”