Tris-Complexes with an Amino Acid

Several years later, the preparative work on the geometrical isomers was renewed by other workers, who applied the three methods to the preparation of geometrical-optical isomers, or diastereoisomers, of tris-complexes from optically active amino acids. In general, four diastereoisomers are possible for a tris(L- or o-amino-acidato) complex fac - r), fac —), wer(-t-) and mer —). 

The geometrical isomers of the tris-complex with P-alanine were synthesized by Celap et al., since the method of Ley-Winkler failed. With the hexaamminecobalt-(III) complex the product was c-isomer with a small amount of mer-isomer. The reaction between sodium tricarbonatocobaltate(III) trihydrate and p-alanine in aqueous solution under heating yielded wer-isomer effectively. 

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