Following the Reaction of Heteroanions inside a {W18O56} Polyoxometalate Nanocage by NMR Spectroscopy and Mass Spectrometry

Qi Zheng; Laia Vilà-Nadal; Christoph Busche; Jennifer S Mathieson; De-Liang Long; Leroy Cronin

doi:10.1002/anie.201502295

Following the Reaction of Heteroanions inside a {W18O56} Polyoxometalate Nanocage by NMR Spectroscopy and Mass Spectrometry

Angew Chem Int Ed Engl. 2015 Jun 26;54(27):7895-9. doi: 10.1002/anie.201502295. Epub 2015 May 27.

Authors

Qi Zheng¹, Laia Vilà-Nadal¹, Christoph Busche¹, Jennifer S Mathieson¹, De-Liang Long¹, Leroy Cronin²

Affiliations

¹ WestCHEM, School of Chemistry, The University of Glasgow, Glasgow G12 8QQ (UK) http://www.croninlab.com.
² WestCHEM, School of Chemistry, The University of Glasgow, Glasgow G12 8QQ (UK) http://www.croninlab.com. Lee.Cronin@glasgow.ac.uk.

Abstract

By incorporating phosphorus(III)-based anions into a polyoxometalate cage, a new type of tungsten-based unconventional Dawson-like cluster, [W18O56(HP(III)O3)2(H2O)2](8-), was isolated, in which the reaction of the two phosphite anions [HPO3](2-) within the {W18O56} cage could be followed spectroscopically. As well as full X-ray crystallographic analysis, we studied the reactivity of the cluster using both solution-state NMR spectroscopy and mass spectrometry. These techniques show that the cluster undergoes a structural rearrangement in solution whereby the {HPO3} moieties dimerize to form a weakly interacting (O3PH⋅⋅⋅HPO3) moiety. In the crystalline state the cluster exhibits a thermally triggered oxidation of the two P(III) template moieties to form P(V) centers (phosphite to phosphate), commensurate with the transformation of the cage into a Wells-Dawson {W18O54} cluster.

Keywords: NMR spectroscopy; cluster compounds; electronic structure; phosphorus; polyoxometalates.