Synthesis and Configuration of New Isomers of the Bis(aminocarboxylato )carbonatocobaltate(III) Ion

In the reaction between potassium tricarbonatocobaltate(III) and the corresponding amino acid (glycine or ~-alanine) two new geometrical isomers of the bis(aminocarboxylato)carbonatocobaltate( III) ion have been obtained. In case of glycine, in addition to the previously described1- 3 cis(N), cis(O)-isomer, the corresponding cis(N), trans(O)-isomer was also obtained, whereas in the reaction with ~-alanine the trans(N), cis(O)-isomer was prepared. The configuration of the trans(N)-isomer was established using its electronic spectrum, whereas the configuration of the other two isomers was determined by means of PMR spectroscopy. In addition, the cis, cis-isomer was resolved into enantiomers by means of A - ( + )ss9-cis(N02), trans(N)-isomer of the bis(S-arginine)dinitrocobalt( III) ion. The absolute configuration of the tJ. - (-)589- -cis(N), cis(O)-isomer was assumed by comparing its CD spectrum with that of the A - ( + )58rcis(N), cis(O)-isomer of the carbonatobis-( S-valinato)cobaltate(III) ion

Study of the reactions of hexanitrocobaltates(III) with amino acids. II. Determination of the configuration of dinitrobis(glycinato)cobaltate(III) ions

In a previously published paper1 we have undertaken a study of the reactions of hexanitrocobaltate(III) with amino acids. The first reaction we studied was that of glycine with potassium and sodium hexanitrocobaltate( III). In such a way the synthesis of a new class of complex compounds, dinitrobis (glycinato)- cobaltates(III) (MI[Co(H2NCH2COO)2(N02)2]), was given

Study of the reaction of hexanitrocobaltates(III) with amino acids. IV. The reations with DL-alanine, D-alanine, L-alanine, and β-alanine

The reactions of alkali hexanitrocobaltates(III) with DL-alanine, D-alanine, L-alanine, and β-alanine have been investigated. Thereby new classes of alkali dinitro-bis (aminoacido)cobaltates(III), M[CoAm2(NO2)2] were obtained. It was established that the products obtained contain two nitro groups in the cis position

Study of the reactions of hexanitrocobaltates(III) with amino acids. VII. Geometrical isomerism and absolute configuration of dinitrobis(aminoacidato)cobaltate(III) ions

Dinitrobis(aminoacidato)cobaltate(III) salts with L-α-aminobutyric acid, aminoisobutyric acid, L-valine, L-norvaline, L-leucine, L-norleucine, and L-isoleucine were prepared and resolved into optical isomers. We report their electronic absorption, circular dichroism and infra-red spectra, and some PMR spectra. The date confirm our earlier assumption of the geometrical isomerism and absolute configuration of analogous ions with glycine, alanine, and β-alanine. The only geometrical isomer found in our preparations is the cis dinitro complex with amino groups trans. The (+)589-optical isomers are assigned the P(C2) absolute configuration

Mixed cobalt(III) complexes with aromatic amino acids and diamine. Part IV. Influence of noncovalent intraand interligand interactions on rotamer population of the S-phenylalaninato and S-tyrosinato side groups in (1,2-diaminoethane)bis(S-aminocarboxylato)cobalt(III) complexes

Rotamer population of S -tyrosinato and S -phenylalaninato ligands side groups in diastereomers of (1,2-diaminoethane) bis ( S -aminocarboxylato)cobalt(III) complexes is calculated by vicinal and proton coupling constant analysis. The effect of noncovalent intra- and interligand interactions on the population of rotamers in D 2 O solution is discussed. It has been established that in all the complexes investigated the most abundant is rotamer t , in which aromatic voluminous moiety and carboxylic group are in an anti position. In almost all complexes the lowest content is of rotamer g , in which these two groups are in the nearest position. Relatively high population of rotamer h in complex 5 tyr , in spite of high steric hindrances, is due to intra- and interligand NH interactions