Synthesis, structure and chirality of some neutral cobalt (III) complexes

<p>Structures are assigned to the six stereoisomers of the complex 2 , 4-pentanedionatobis(S-alaninato)cobalt(III) and to the diastereomers of bis(2, 4-pentanedionato)S-aminoacidatocobalt(III), where the S-amino acid is S-alanine, S-valine, N-methyl-S-alanine and N-methyl-S-valine. Adsorption column chromatography on alumina was used to separate these neutral complexes which are soluble in water and non-aqueous solvents. Electronic absorption spectra are interpreted in assigning geometric isomers and C-O bond anisotropic deshielding arguments are applied to proton nmr chemical shifts in making chiral assignments of the helical diastereomers. A comparison is made between C-O bond deshielding and N-D steric compression. The proton nmr assignments are shown to be independent of the solvent used in measuring chemical shifts and agree with assignments made from circular dichroism spectra in every case. No stereospecificity was observed in these systems or for the complexes bis(2 , 4-pentanedionato)aminoacidato- cobalt(III) where the amino acid is sarcosine, S-proline and S-serine. A convenient, high yield synthesis of tris(2 ,4-pentanedionato)-rhodium(III) is reported.</p>

Name thesis:degree_name

Doctor of Philosophy (PhD)

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Chemistry

Year

1974

Author dc:creator

• Seematter, David J.

Repository record dc:identifier

https://commons.und.edu/theses/640

OAI identifier oai:identifier

oai:commons.und.edu:theses-1640