Ab initio study of the effect of solvent on energies and rotational barriers in 2,3-butadienal and 2,3-butadienoyl fluoride and chloride

The effect of the inclusion of solvation effects and electron correlation on the calculation of energies and rotational barriers in 2,3-butadienal and 2,3-butadienoyl fluoride and chloride was investigated by ab initio calculations with 6-31G* (6-311G* for the aldehyde) basis set. The calculations were carried out at restricted Hartree-Fock (HF) and second-order Møller-Plesset (MP2) levels. From SCRF calculation, the presence of solvent was predicted to have a noticeable effect only on 2,3-butadienal and 2,3-butadienoyl fluoride. This was a result of a greater charge density variation on going from the s-cis to s-trans conformer particularly in the case of 2,3-butadienal. This variation leads to a greater solute-solvent dipolar interaction and hence to a higher energy difference and rotational barrier,