1002 Chemistry Letters 2000

Free Energy Perturbation Studies on Enantiomeric Discrimination of Pyridino-18-Crown-6 Ethers

Sungu Hwang, One-Sun Lee, and Doo Soo Chung*
School of Chemistry, Seoul National University, Seoul 151-747, Korea

We performed FEP and MD simulations on enantiomeric complexes of seven 18-crown-6 ether compounds and a chiral protonated amine to obtain the free energy differences, and to elucidate the mechanism responsible for enantioselectivity. The FEP calculation reproduced the experimental enantioselectivity quite well. We partitioned the binding free energy in solution into the binding free energy in the gas phase and the solvation energy, and discussed the results. In the MD simulations, the detailed motion of host-guest complexes was monitored.