AB-INITIO SCF INVESTIGATION OF THE INTRAMOLECULAR HYDROGEN-BONDING INEPSILON-AMINOHEXANOIC ACID

Ab initio RHF results (geometry data and potential barriers) are repor ted for the 14 symmetry unique local minima in the potential energy su rface of epsilon-aminohexanoic acid, which contain an intramolecular N ...H-O hydrogen bond. Comparison of characteristic data with those of the homologs with fewer carbon atoms shows that delta-aminopentanoic a cid forms the most stable hydrogen bonds. In contrast to these homolog s, the -COOH group is not limited to anti-periplanar orientation in th e H-bonded conformers of epsilon-aminohexanoic acid: In four such conf ormers, it occurs in ayn-clinal orientation. (C) 1994 John Wiley & Son s, Inc.