Theoretical investigation of 5-(2-acetoxyethyl)-6-methylpyrimidin-2,4-dione: conformational study, NBO and NLO analysis, molecular structure and NMR spectra.

Abstract Structural and conformational, natural bond orbital (NBO) and nonlinear optical (NLO) analysis was performed, and 1 H and 13 C NMR chemical shifts values of 5-(2-Acetoxyethyl)-6-methylpyrimidin-2,4-dione [C 9 H 12 N 2 O 4 ] in the ground state were calculated by using Density Functional Theory (DFT-B3LYP/6-311++G(d,p)) and Hartree–Fock (HF/6-311++G(d,p)) methods. The NMR data were calculated by means of the GIAO, CSGT, and IGAIM methods. In addition, the molecular frontier orbital energies, thermodynamic parameters (in the range of 200–700 K), molecular surfaces, Mulliken charges and atomic polar tensor-based charges were investigated. Besides, the analysis of all possible conformational of the title compound, a detailed potential energy curve for τ 1 (C 8 O 3 C 10 O 4 ), τ 2 (C 8 O 3 C 10 C 11 ) and τ 3 (C 5 C 7 C 8 O 3 ) dihedral angles were performed in steps of 10° from 0° to 360°, and depicted to find the most stable form. Finally, the calculated HOMO and LUMO energies show that charge transfer occurs within the title compound.