Towards the accurate calculation of 183W NMR chemical shifts in polyoxometalates: the relevance of the structure

Vilà-Nadal, L. , Sarasa, J. P., Rodríguez-Fortea, A., Igual, J., Kazansky, L. P. and Poblet, J. M. (2010) Towards the accurate calculation of 183W NMR chemical shifts in polyoxometalates: the relevance of the structure. Chemistry: An Asian Journal, 5(1), pp. 97-104. (doi: 10.1002/asia.200900263)

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Abstract

DFT calculations were carried out to study 183W NMR chemical shifts in the family of the Keggin anions with formula α-[XW12O40]q− (X=B, Al, Si, P, Ga, Ge, As, Zn), in the β- and γ-[SiW12O40]4− geometric isomers, in the derivative Dawson anion [P2W18O62]6−, and in the most symmetrical Lindqvist [W6O19]2− anion and its derivative [W10O32]4−. In this article, we show that the geometry employed in the calculation of NMR chemical shifts in polyoxotungstates is extremely important if we want to be quantitative. Using very large basis sets of QZ4P quality and taking into account the conductor-like screening model (COSMO) to account for solvent effects (aqueous and organic solutions), good geometries were found for the polyoxoanions. From these optimal geometries the 183W NMR chemical shifts were computed with the more standard basis sets of TZP quality and including spin–orbit corrections inside the zero-order regular approximation (ZORA) to describe the relativistic effects of the internal electrons. With this strategy the mean absolute error between experimental and theoretical values was found to be less than 10 ppm, which is similar to the experimental error. We also discuss how the geometry of the polyoxoanion influences on the shielding.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Vila-Nadal, Dr Laia
Authors: Vilà-Nadal, L., Sarasa, J. P., Rodríguez-Fortea, A., Igual, J., Kazansky, L. P., and Poblet, J. M.
College/School:College of Science and Engineering > School of Chemistry
Journal Name:Chemistry: An Asian Journal
Publisher:Wiley
ISSN:1861-4728
ISSN (Online):1861-471X

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