Artículo
A simple analysis of the influence of the solvent-induced electronic polarization on the 15N magnetic shielding of pyridine in water
Gester, Rodrigo M.; Georg, Herbert C.; Fonseca, Tertius L.; Provasi, Patricio Federico
; Canuto, Sylvio
Fecha de publicación:
05/2012
Editorial:
Springer
Revista:
Theoretical Chemistry Accounts
ISSN:
1432-881X
e-ISSN:
1432-2234
Idioma:
Inglés
Tipo de recurso:
Artículo publicado
Clasificación temática:
Resumen
Electronic polarization induced by the interaction of a reference molecule with a liquid environment is expected to affect the magnetic shielding constants.Understanding this effect using realistic theoretical models is important for proper use of nuclear magnetic resonance in molecular characterization. In this work, we consider the pyridine molecule in water as a model system to briefly investigate this aspect. Thus, Monte Carlo simulations and quantum mechanics calculations based on the B3LYP/6-311++G(d,p) are used to analyze different aspects of the solvent effects on the 15N magnetic shielding constant of pyridine in water. This includes in special the geometry relaxation and the electronic polarization of the solute by the solvent. The polarization effect is found to be very important, but, as expected for pyridine, the geometry relaxation contribution is essentially negligible. Using an average electrostatic model of the solvent, the magnetic shielding constant is calculated as -58.7 ppm, in good agreement with the experimental value of -56.3 ppm. The explicit inclusion of hydrogen-bonded water molecules embedded in the electrostatic field of the remaining solvent molecules gives the value of -61.8 ppm.
Palabras clave:
Nmr
,
Chemical Shielding
,
Solvent Effects
,
Qm/Mm
,
Electronic Polarization Effects
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Articulos(IMIT)
Articulos de INST.DE MODELADO E INNOVACION TECNOLOGICA
Articulos de INST.DE MODELADO E INNOVACION TECNOLOGICA
Citación
Gester, Rodrigo M.; Georg, Herbert C.; Fonseca, Tertius L.; Provasi, Patricio Federico; Canuto, Sylvio; A simple analysis of the influence of the solvent-induced electronic polarization on the 15N magnetic shielding of pyridine in water; Springer; Theoretical Chemistry Accounts; 131; 5-2012; 1220-1228
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