Molecular dynamics simulations of the inclusion process of 1-bromoadamantane with beta-cyclodextrin

Results are reported from molecular dynamics simulations with the AMBER* force field of the inclusion process of 1-bromoadamantane and beta-cyclodextrin in water as a solvent. A parallel molecular mechanics minimization study was also carried out, using different force fields (AMBER*, MM2* and MM3*) and water as a solvent. Valuable information was obtained regarding the dependence of the results from the force field used, and for the dependence of the molecular dynamics simulations on the constraints imposed on the host-guest supermolecule. The molecular mechanics potential energy of complexation in water (ca. 10.5 kcal mol(-1) calculated with AMBER*) is mainly due to the van der Waals interactions. The electrostatic polarization component of the solvation energy term disfavours the process by about 5.0 kcal mol(-1). The computed results point also to a tendency of balancing between two energy components (electrostatic and solvation) upon variation of the distance between the guest molecule and the beta-cyclodextrin.