Quantum Chemical Approaches on the structures of CH3OCH3/H2O and CH3OCF3/H2O

Abstract

Intermolecular interactions play a significant role in the field of physics, chemistry and biology. The study of intermolecular interactions is a useful step toward gaining a basic understanding of the dynamic behaviour of molecules in various environments. In the present study, high-level ab initio calculations [MP2] using correlation consistent basis sets of Dunning [aug-cc-pVDZ, aug-cc-pVTZ] were carried out to study the potential energy surfaces of CH3OCH3/H2O and CH3OCF3/H2O Van der Waals dimers and to clarify the stable structures of these clusters. For the calculation of interaction energies, the basis set superposition errors (BSSE) were estimated by counterpoise method. One stable structure for CH3OCH3/H2O dimer has been found. For the optimized structure, the H2O molecule is outside the C-O-C plane of the CH3OCH3, and the bond angle O(CH3OCH3)---H-O(H2O) is approximately 180°. On the other hand, for the stable structure of CH3OCF3/H2O, the H2O molecule exists in the C-O-C plane of the CH3OCH3/H2O molecule. The O-H(H2O)--F(CH3OCH3) interaction is considered to be significant. The details of the potential energy surfaces are discussed.