A wheel-shaped Zr-substituted phosphotungstate [{Zr(C 2 O 4 ) 2 } 3 (PO 4 )(P 6 W 39 O 150 )] 39- with tunable proton conduction properties.

A wheel-shaped Zr-substituted phosphotungstate, [N(CH 3 ) 4 ] 2 K 16 Na 10.5 H 10.5 [{Zr(C 2 O 4 ) 2 } 3 (PO 4 )(P 6 W 39 O 150 )]·45H 2 O (1), was synthesised from a hexavacant Dawson-type precursor [H 2 P 2 W 12 O 48 ] 12- via a conventional solution method. Compound 1 features a wheel-shaped polyanion comprising an annular [P 6 W 39 O 150 ] 36- cluster supported by a turbine-shaped [{Zr(C 2 O 4 ) 2 } 3 (PO 4 )] 3- fragment, with three oxalate groups covalently anchored to W atoms. Compound 1 was systematically characterized by IR, UV, PXRD, TGA and 31 P NMR spectra. The 31 P NMR spectra over time were monitored to verify the stability of 1 in aqueous solution. This compound possesses remarkable proton conductive behavior with a high conductivity of 1.18 × 10 -2 S cm -1 at 368 K.