Theoretical evaluation of symmetrical α,α′,δ,δ′-tetramethyl cucurbit[6]uril for haloalkane 1-(3-chlorophenyl)-4-(3-chloropropyl)-piperazinium and chloroform encapsulation

Abstract

In the present study, structures and electronic properties of inclusion complexes of TMeQ[6] with PZ+ and CHCl3 were investigated, using the density functional theory calculations and molecular dynamic (MD) simulations. Theoretical results at the M05-2X-D3/6-31G(d) level clearly confirm that the inclusion complex formation is energetically feasible, and PZ+@TMeQ[6] formation is more favorable than CHCl3@TMeQ[6]. Natural bond orbital and quantum theory of atoms in molecules analyses were applied to investigate the electron transfer and topological properties of the interactions of TMeQ[6] and guest compounds. Non-covalence nature, van der Waals, of the host–guest interactions was confirmed by non-covalent interactions–reduced density gradient method. Finally, the effect of solvent was taken into account by using the MD simulations. According to H-bond analysis in the MD simulations, the importance of hydrogen bonding interactions was confirmed only in PZ+@TMeQ[6] complex, the studied inclusion complexes are more stable in chloroform, because of a high value of van der Waals interactions. This study show that TMeQ[6] as a good candidate for sensing. A joint MD/QM study confirms the side chain effect of PZ+ on the response ability improvement of TMeQ[6].