Molecular structure, conformation, and large amplitude motion of barbituric acid as studied by gas-phase electron diffraction and quantum chemical calculations

作者：Dorofeeva Olga V^*; Marochkin Ilya I; Karasev Nikolai M; Shishkov Igor F; Oberhammer Heinz

来源：Structural Chemistry, 2011, 22(2): 419-425.

DOI：10.1007/s11224-011-9743-x

• Barbituric acid
• Structure
• Electron diffraction
• B3LYP
• MP2

B3LYP and MP2(Full) calculations with large basis sets predict the planar equilibrium structure of barbituric acid and reveal large amplitude ring puckering motion which is associated with envelope conformation. The potential function for this motion has only one minimum. This function was used in the analysis of the gas-phase electron diffraction (GED) data in terms of a dynamic model. The least-squares refinements applying dynamic model agree well with the GED data, whereas the agreement is not satisfactory for a planar static model. There is a good agreement between the experimental structural parameters and those from B3LYP/cc-pVTZ calculation. The MP2(Full)/cc-pVTZ values of C-C and C-N bond lengths are 0.02-0.03 less than the experimental ones. The structure of the molecule is compared with the structures of several related molecules.

• 出版日期2011-4