Rationalizing some experimental facts on the complexation of 2-methyl naphthalenecarboxylate and hydroxypropyled cyclodextrins by molecular mechanics and molecular dynamics

Molecular mechanics (MM) and Molecular dynamics (MD) calculations were applied to study the complexation of 2-Methyl naphthalenecarboxylate (2MN) and 2-hydroxypropyl -α-, -β-, and γ-cyclodextrins (HPCDs) in the presence of water. Results showed that 1:1 complexes of 2MN with modified cyclodextrins are stable and that the non-bonded van der Waals interactions are mainly responsible for the complexation. Theoretical results are in good agreement with fluoresence results and they permit us to explain the signs and quantitative differences of ΔH0 and ΔS0 on the basis of the different cavity sizes and the movement of the guest inside the HPCD cavity. Results also reveal a more favorable complexation when 2MN approaches on its polar side.