A theoretical study on 2-chloro-5-(2-hydroxyethyl)-4-methoxy-6-methylpyrimidine by DFT/ab initio calculations

Quantum chemical calculations have been performed to study the molecular geometry, ¹H and ¹³C NMR chemical shifts, conformational, natural bond orbital (NBO) and nonlinear optical (NLO) properties of the 2-chloro-5-(2-hydroxyethyl)-4- methoxy-6-methylpyrimidine molecule in the ground state using DFT and HF methods with 6-311++G(d,p) basis set. The optimized geometric parameters and ¹H and ¹³C NMR chemical shifts have been compared with the experimental values of the title molecule. The results of the calculations show excellent agreement between the experimental and calculated frequencies at B3LYP/6-311++G(d,p) level. In order to provide a full understanding of the properties of the title molecule in the context of molecular orbital picture, the highest occupied molecular energy level (E_HOMO), the lowest unoccupied molecular energy level (E_LUMO), the energy difference (DE) between E_HOMO and E_LUMO, electronegativity (χ), hardness (η) and softness (S) have been calculated using B3LYP/6-311++G(d,p) and HF/6-311++G(d,p) levels. The calculated HOMO and LUMO energies show that the charge transfer occurs within the title molecule.