A Dawson-type {P 4 W 24 } modified using phenylphosphonic acid with excellent proton conductivity.

A case of organic-inorganic hybridized phosphotungstate modified using aromatic organophosphonic acid, K 4 Na 4 H 11 [KCo 2 (H 2 O) 10 P 4 W 24 O 92 {(PhPO) 2 }]·48H 2 O (1), was successfully synthesized in conventional aqueous solution. The prominent structural feature is that the total structure of [KP 4 W 24 O 92 {(PhPO) 2 }] 23- resembles a V-shaped structure, which was stabilized by two [Co(H 2 O) 5 ] 2+ ions. Furthermore, it can be connected into a three-dimensional mesh structure using K + ions. Surprisingly, 1 possesses a remarkably high proton conductivity of 1.59 × 10 -2 S cm -1 at 95% RH and 318 K probably due to the fact that its structure contains large amounts of lattice water molecules, coordination water molecules and counter cations.