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Stereoselective Formation of Ternary Copper(II) Complexes of (S)-amino-acid amides and (R)- or (S)-amino acids in aqueous solution

✍ Scribed by Francesco Dallavalle; Giuseppina Folesani; Rosangela Marchelli; Gianni Galaverna

Publisher
John Wiley and Sons
Year
1994
Tongue
German
Weight
431 KB
Volume
77
Category
Article
ISSN
0018-019X

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✦ Synopsis

Abstract

Formation constants of ternary complexes of Cu^II^ with (S)‐amino‐acid amides (phenylalaninamide, prolinamide, and tryptophanamide) and (R)‐ or (S)‐amino acids (valine, phenylalanine, proline, and tryptophan) were determined potentiometrically at 25° and I = 0.1M (KC1). Significant stereoselectivity was found for the systems (S)‐tryptophanamide/proline, (S)‐prolinamide/tryptophan, and (S)‐phenylalaninamide/proline, the diastereoisomeric complexes with ‘homochiral’ (SS) being more stable than with ‘heterochiral’ (SR) ligands. The stereoselectivity observed may be explained on the basis of repulsive interactions between the ligand side‐chain residues. The present data on the stability of mixed complexes in solution allow to draw some conclusions on the mechanism of chiral discrimination of amino acids in HPLC (reversed‐phase) using Cu^II^ complexes of (S)‐amino‐acid amides as selectors for ligand‐exchange chromatography (LEC).

📜 SIMILAR VOLUMES

Stereoselectivity in reactions of metal
Stereoselectivity in reactions of metal complexes. V. Synthesis of mixed-ligand cobalt(III) complexes with (S)-aspartic-N-monoacetic acid and different amino-acids
✍ Gérard Colomb; Klaus Bernauer 📂 Article 📅 1977 🏛 John Wiley and Sons 🌐 German ⚖ 370 KB

## Abstract The synthesis of mixed‐ligand cobalt(III) complexes with (__S__)‐aspartic‐N‐monoacetic acid ((__S__)‐AMA) and different amino‐acids Na[Co((__S__)‐AMA)(AA)] (AA = gly, (__R__)‐ and (__S__)‐ala, val, phe, ser and leu) leads to a mixture of __cis__‐N‐ and __trans__‐N‐isomers. These isomers