Chiral metal-complexes XLII. Reversed-phase high-performance liquid-chromatographic separation of racemic dipeptides as their ternary Co(III) complexes with a chiral triamine

The enantiomeric and diastereoisomeric dipeptides Gly-R,S-Val, Gly-R,S-Leu, GIy-R,S-Phe, R,S-Leu-GIy, R,S-Leu-R,S-AIa and R,S-Leu-R,S-Phe have been separated by RP-HPLC methods when coordinated in ternary Co(Ill) complexes [Co(R,R-benzet)(peptidato)] 2+ [benzet = N-benzyl-N'-(2-picolyl-l,2-diaminocyclohexane)], on Amex Prepsil columns under a variety of conditions. A method is illustrated for the recovery of the pure peptides from the separated diastereoisomers. The method appears to be applicable for dipeptides, in general.