The molecular structure of uracil: an electron diffraction study

Molecular structure of caffeine as determined by gas electron diffraction aided by theoretical calculations

“…In Table 3, the structural parameters of caffeine monohydrate in the crystal [8] and the gas-phase structures of the related molecules, uracil [26] and imidazole [27,28] (see Fig. 1), are also listed.…”

“…The one-to-one comparison between the N-C bond lengths of caffeine and uracil [26] shows disagreement. However, the averaged value of the r g (N-C) for the 6-membered ring of caffeine (1.394 ± 0.003 Å) is in a good agreement with that of uracil (1.399 ± 0.006 Å).…”

“…[26]. Some bond lengths were calculated from the listed r a distances and 20 the mean amplitudes, l.…”

Theoretical studies of uracil–(H2O)n (n=1–7) clusters by ab initio and ABEEMσπ/MM fluctuating charge model

“…Because of the simple chemical structure of uracil, the studies of its hydration have received a great deal of attention. So far, the important information of uracil and complexes with water molecules has been determined by some available experimental techniques [2][3][4][5][6][7], such as electron diffraction [3], X-ray diffraction [2,4], and so on. To the best of our knowledge, the two major types of intermolecular hydrogen bonds (H-bonds) that occur in uracil-water complexes are C@OÁ Á ÁHw and N-HÁ Á ÁOw, respectively.…”

Quantum-chemical study, IR spectra, and intramolecular hydrogen bonds in dimeric 5- and 6-methyluracils

“…The experimental gas-phase geometries of the monomeric molecules are scarcely available. The structure of uracil is only known [8]. Gas-phase electron diffraction showed that the uracil molecule is planar at the experimental temperature (210oC) and exists in the keto form.…”