Theoretical study of the syn and anti thiophene-2-aldehyde conformers using density functional theory and normal coordinate analysis

An extensive computational study of thiophene-2-aldehyde conformers syn and anti has been carried out using density functional (DFT). From these calculations, B3LYP/6-31G(d) has been chosen as it produces results remarkably close in comparison with experimental ones, with less demanding computational time. Data obtained from DFT computation were used to perform a normal coordinate analysis to complement and give insight in the experimental vibrational assignment. Calculated dipole moments and relative stabilities of isomers coherently support experimental statements given in the literature.