One-Sun Lee, Sungu Hwang, Doo Soo Chung
Department of Chemistry
Seoul National University, Seoul, Korea
Discrimination of chiral amines by dimethyldiketopyridino-18-crown-6 (1) is studied by FEP and MD method. The optically active amines in this study include a-(1-naphthyl)ethylamine (2), methylbenzylamine (3), cyclohexylethyl amine (4), and sec-butylamine (5). The starting geometries of the host-guest complexes in the simulations were either taken from the X-ray crystallographic structures if available or otherwise obtained from modifying a related X-ray structure followed by performing MD and MM simulations. The trends of the calculated binding free energy differences between (R)-guest:(S,S)-host and (S)-guest:(S,S)-host complexes were in good agreement with the experimental results reported earlier. The structural features were in good agreement with the experiments. The suggested chiral discrimination mechanism from the experiments (p-p interaction and steric repulsion) was validated by our MD simulation results.