Carbon-13 nuclear magnetic resonance spectra of potassium (ethylenediaminetetraacetato)cobaltate(III) in organic solvents
The carbon-13 NMR spectra of the (Co(edta))/sup /minus// (edta = ethylenediaminetetraacetate) anion were observed in water and a variety of organic solvents: ethylene glycol, methanol, formamide, ethanol, 2-propanol, chloroform, dichloromethane, dimethyl sulfoxide, acetonitrile, dimethylformamide, benzonitrile, and dimethylacetamide. The spectra in organic solvents were obtained after 1-2-h accumulations for the concentrated solutions (0.5 M) of the complex anion that were prepared by the addition of a macrobicyclic polyether, cryptand 222, to the solvents. The /sup 13/C NMR signals of the coordinated carboxylates are markedly shifted downfield in protic solvents in comparison with aprotic solvent (the greatest difference in chemical shift is 3.9 ppm), while the NMR chemical shifts of methylene carbons of ligands are not significantly influenced by solvent molecules. The magnitudes (/sigma/ values) of this downfield shift of the coordinated carboxylate /sup 13/C signals are found to be correlated linearly with the electrophilic ability of the solvent molecules. This finding leads to the conclusion that the (Co(edta))/sup /minus// anion interacts with solvent molecules through the hydrogen-bonding between solvent hydrogens and carboxyl oxygens of the complex anion. 10 references, 4 figures, 1 table.
- Research Organization:
- Univ. of Aichi Prefecture, Nagoya (Japan)
- OSTI ID:
- 5775999
- Journal Information:
- Inorg. Chem.; (United States), Journal Name: Inorg. Chem.; (United States) Vol. 27:16; ISSN INOCA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400201* -- Chemical & Physicochemical Properties
400202 -- Isotope Effects
Isotope Exchange
& Isotope Separation
ALKALI METAL COMPOUNDS
AMINO ACIDS
CARBON 13
CARBON ISOTOPES
CARBOXYLIC ACIDS
CHELATING AGENTS
COBALT COMPOUNDS
DATA
EDTA
EVEN-ODD NUCLEI
EXPERIMENTAL DATA
INFORMATION
ISOTOPES
LIGHT NUCLEI
MOLECULAR STRUCTURE
NMR SPECTRA
NUCLEI
NUMERICAL DATA
ORGANIC ACIDS
ORGANIC COMPOUNDS
POTASSIUM COMPOUNDS
SPECTRA
STABLE ISOTOPES
TRANSITION ELEMENT COMPOUNDS