Colorimetric enantiodiscrimination of alpha-amino acids in protic media.
A new method is described for the determination of optical purity of alpha-amino acid samples in protic media. No derivatization of the analyte or multistep synthesis is required, and high accuracy is obtained from the colorimetric output. Chiral discrimination is achieved through the use of an optically pure trans-1,2-diaminocyclohexane-derived Cu(II)-containing host that differentiates amino acid enantiomers by a factor of about 2. Enantioselective signaling arises from the implementation of an indicator displacement assay based on competitive Cu(II) coordination involving the chiral Cu(II)-containing host, the amino acid guest, and a metal ion indicator. The molecular structure of the host/guest complex was determined by X-ray analysis and exhibits chelation of the Cu(II) center by the amino acid to provide substrate organization.
Folmer-Andersen
J Frantz
JF
Department of Chemistry and Biochemistry, The University of Texas at Austin, Austin, Texas 78712, USA.
Lynch
Vincent M
VM
Anslyn
Eric V
EV
D000596:Amino Acids / Q000032:analysis / Q000737:chemistry*; D003124:Colorimetry / Q000379:methods*; D003300:Copper / Q000737:chemistry; D018360:Crystallography, X-Ray; D003514:Cyclohexylamines / Q000737:chemistry; D057927:Hydrophobic and Hydrophilic Interactions; D007700:Kinetics; D009942:Organometallic Compounds / Q000737:chemistry; D012997:Solvents; D013056:Spectrophotometry, Ultraviolet; D013237:Stereoisomerism
D000596:Amino Acids; D003514:Cyclohexylamines; D009942:Organometallic Compounds; D012997:Solvents; D003300:Copper; C030435:1,2-cyclohexanediamine