Davankov ligand exchange chiral

V. A. Davankov, Ligand-exchange phases in Chiral Separations by HPLC, A. M. Krstulovic, Ellis Horwood Ltd., Chichester (1989) Chapter 15. 

V. A. Davankov, Ligand exchange chromatography of chiral compounds, in D. Cagniant (ed.), Complexation Chromatography, Marcel Dekker, New York, 1992, p. 197. 

Based on preliminary results from Helfferich130, further developments by Davankov and co-workers5 131 133 turned the principle of chelation into a powerful chiral chromatographic method by the introduction of chiral-complex-forming synlhetie resins. The technique is based on the reversible chelate complex formation of the chiral selector and the selectand (analyte) molecules with transient metal cations. The technical term is chiral ligand exchange chromatography (CLEC) reliable and complete LC separation of enantiomers of free a-amino acids and other classes of chiral compounds was made as early as 1968 131. 

Ligand exchange has proved to be very successful in the separation of several enantiomers. Davankov and Rogozhin (41) used chiral copper complexes bonded to silica. The enantiomeric separation is based essentially on the formation of diastereomeric mixed complexes with different thermodynamic stabilities. It is generally accepted that chiral discrimination proceeds via the substitution of one ligand in the coordination sphere of the metal ion. Ligand exchange technique is especially effective for the enantiomeric resolution of aminoacids, aminoacids derivatives, and hydroxy acids (42). 

Davankov VA, Ligand exchange phases, in Chiral Separations by HPLC, Krstulovic A (Ed.), Ellis Horwood, Chichester, p. 447 (1989). 

V. A. Davankov and A. A. Kurganov, The role of achiral sorbent matrix in chiral recognition of amino acid enantiomers in ligand-exchange chromatography, Chromatographia, 77 696 (1983). 

Another molecular rect nition force is the metal-complex formation realized in chiral ligand-exchange chromatography (CLEC). The technique was first proposed by Helf-ferich ]400] and was turned into a powerful chromatographic technique by Davankov and co-workers [8,401 j. This technique is based on a reversible chelate-complex forma-... 

Davankov, V. A. 30 years of chiral ligand exchange. Enantiomer, 2000, 5, 209-223. 

Davankov VA. Ligand-exchange phases. In Krstulovic AM, editor. Chiral separations by HPLC. New York Ellis Horwood Limited 1989. p. 175—93. 

The three-point attachment rule is largely qualitative and only valid with bimolecular processes (e.g., small Pirkle or ligand-exchange selectors). Another drawback of this model approach is that it cannot be applied to enantiomers with multiple chiral centers. Sundaresan and Abrol [15] proposed a novel chiral recognition model to explain stereoselectivity of substrates with two or three stereo centers requiring a minimum of four or five interaction points. In the same way, Davankov [16] pointed out that much more contact points are realized with chiral cavities of solids. 

The solute is involved in a ligand-exchange complex (Davankov chiral... 

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