Stereochemical differentiation of five diastereomeric pairs of β-amino acids, di-endo- and di-exo-2,3-disubstituted norbornane and norbornene amino acids, cis- and trans-2-aminocyclohexane-, 2-amino-4-cyclohexene-, and 2-aminocyclopentanecarboxylic acids, was investigated via the kinetic method with metal-bound trimeric complexes. This is the first time that diastereomers (di-endo/di-exo and cis/trans) have been differentiated with metal-bound trimeric complexes and the kinetic method. Moreover, determination of diastereochemical excess by the kinetic method was applied to norbornane β-amino acids and cyclopentane β-amino acids. Experiments showed that a remarkable differentiation of the studied diastereomers was achieved. It was observed that better selectivity values correlated to more rigid structures. The reference compounds for the studied β-amino acids varied from α-amino acids to some β-amino acids. In addition, variation of the metal ion (Cu2+ and Ni2+) had some role in the selectivity values obtained. Ab initio and hybrid density functional theory calculations were performed to clarify the results obtained by mass spectrometry.
|Number of pages||8|
|Journal||Journal of the American Society for Mass Spectrometry|
|Publication status||Published - Jan 1 2009|
ASJC Scopus subject areas
- Structural Biology