Carbonates, thiocarbonates, and the corresponding monoalkyl derivatives: III. The 13C chemical shift tensors in potassium carbonate, bicarbonate and related monomethyl derivatives.
Solid State Nucl Magn Reson
; 22(1): 29-49, 2002 Aug.
Article
em En
| MEDLINE
| ID: mdl-12421088
ABSTRACT
The principal values of the 13C chemical shift tensors in potassium carbonate (K2CO3), trithiocarbonate (K2CS3), bicarbonate (KHCO3), methylcarbonate (KO2COCH3), S-methyl-monothiocarbonate (KO2CSCH3), O-methyl-monothiocarbonate (KOSCOCH3), S-methyl-dithiocarbonate (KOSCSCH3), and O-methyl-dithiocarbonate (KS2COCH3), were measured in solid-state nuclear magnetic resonance experiments. Chemical shift tensor calculations on the corresponding isolated anions were used to assign the chemical shift tensor orientations in the molecular frames of all anions. The correlation between experimental and calculated principal values improves significantly when the calculations are performed on isolated anions with proton-optimized X-ray geometries rather than on isolated anions with fully optimized geometries. Further considerable improvement in the correlation is achieved by utilizing the embedded ion method, which was recently developed to include electrostatic crystal potentials in chemical shift tensor calculations on ionic compounds. Similarities and differences in the chemical shift tensor orientations and principal values of the trigonal sp2 carbon atoms in the carbonate and thiocarbonate anions are compared with those known for condensed polyaromatic hydrocarbons.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Potássio
/
Bicarbonatos
/
Isótopos de Carbono
/
Carbonatos
/
Espectroscopia de Ressonância Magnética
/
Compostos de Potássio
/
Ânions
/
Modelos Químicos
Idioma:
En
Revista:
Solid State Nucl Magn Reson
Assunto da revista:
DIAGNOSTICO POR IMAGEM
/
MEDICINA NUCLEAR
Ano de publicação:
2002
Tipo de documento:
Article
País de afiliação:
Estados Unidos