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Theoretical studies in molecular recognition: Enantioselectivity in chiral chromatography
Author(s) -
Lipkowitz Kenny B.,
Baker Brian,
Zegarra Richard
Publication year - 1989
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/jcc.540100513
Subject(s) - diastereomer , stereocenter , van der waals force , chemistry , intermolecular force , binding energy , molecular recognition , phase (matter) , enantioselective synthesis , computational chemistry , stereochemistry , molecule , organic chemistry , atomic physics , physics , catalysis
The enantioselective binding of optical analytes on chiral stationary phases used in column chromatography is investigated with molecular modeling techniques. By rolling the analytes over the van der Waals surface of the phase, configurations are sampled and free energies of transient diastereomeric complexes are computed. These free energies allow us to compute chromatographic separability factors and a linear relationship between computed and observed values is found. The intermolecular potential energy surfaces of these diastereomeric complexes are flat with gentle rolling hills and multiple minima. The binding sites are ill‐defined and the analytes are found to freely slide over the chiral stationary phases. An energy partitioning algorithm is used to determine how much of the total binding energy is attributable to a given molecular fragment on the phase. It is found that the fragments of the phase bearing the stereogenic carbons are the least cognizant of differences between optical antipodes.