Chiral separation of dansyl amino acids by ligand exchange capillary electrochromatography in a low molecular weight organogel.
Chiral electroseparation is demonstrated, for the first time, by a low molecular weight organogel filled capillary. Five pairs of dansylated amino acids were separated by copper ligand exchange on a trans-(1S,2S)-1,2-bis-(dodecylamido) cyclohexane (1) gel in methanol. Low molecular weight organogels are emerging materials that form stable, fibrillar, thermoreversible and thixotropic gels without covalent bonding of their monomeric building blocks. The dependence of chiral resolution and complex formation stability on the pH*, the ratio between copper and the D-valine selector, as well as other parameters were investigated revealing trends that were unparalleled in previously reports on copper ligand exchange of dansylated amino acids. These observations were explained in view of a simple stacking model of (1) and the difference in axial ligation of the amide carbonyl backbone of the gel to the dansyl D- or L-amino acid:D-valine:copper ternary complexes.
Mizrahi
Shaul
S
The Chemistry Institute, The Casali Institute of Applied Chemistry, The Hebrew University of Jerusalem, Jerusalem, Israel.
Rizkov
Dan
D
Shames
Alexander I
AI
Lev
Ovadia
O
D000577:Amides / Q000737:chemistry; D000596:Amino Acids / Q000737:chemistry*; D053801:Capillary Electrochromatography / Q000295:instrumentation / Q000379:methods*; D003300:Copper / Q000737:chemistry; D003509:Cyclohexanecarboxylic Acids / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008024:Ligands; D008970:Molecular Weight; D010713:Phosphatidylcholines / Q000737:chemistry*; D013237:Stereoisomerism; D014633:Valine / Q000737:chemistry
C533797:1,2-bis(dodecylamido)cyclohexane; C496906:1-myristoyl-2-(12-((5-dimethylamino-1-naphthalenesulfonyl)amino)dodecanoyl)-sn-glycero-3-phosphocholine; D000577:Amides; D000596:Amino Acids; D003509:Cyclohexanecarboxylic Acids; D008024:Ligands; D010713:Phosphatidylcholines; D003300:Copper; D014633:Valine