Molecular-mechanical study of cyclodextrin and its inclusion complexes

Abstract

Molecular-mechanical calculations have been performed on beta-cyclo-dextrin (β-CD) and its inclusion complexes using the MM2 force field. The guest molecules involved were nitrophenol (4-NP, 3-NP, 2-NP), nitroaniline (4-NA, 3-NA, 2-NA) and dihydroxybenzene (1,4-DH, 1,3-DH, 1,2-DH). A symmetric structure of β-CD was optimized as the first step of calculation. The preferred way of a guest molecule approach to the cavity in β-CD is discussed, based on the energy variation in this process. A good correlation was found between the order of variation of van der Waals energy and that of K_d of these inclusion complexes, as obtained by electrochemistry.