A pyrazine-2,3-dicarboxylic acid hybrid arsenotungstate with decent proton conduction property.

• A pzdc2- ligand covalently functionalized arsenotungstate was synthesized. • Four pzdc2– ligands are coordinated with w atoms of POMs skeleton. • This hybrid arsenotungstate displays decent proton conduction property. A pyrazine-2,3-dicarboxylic acid hybrid arsenotungstate K 5 Ba 5 H{Ba[AsW 11 O 37 (pzdc) 2 ] 2 }·22H 2 O (1 , H 2 pzdc = pyrazine-2,3-dicarboxylic acid) has been synthesized. This compound displayed a dimeric polyanion which consisted of two ancient official cap-shaped [AsW 11 O 37 (pzdc) 2 ]9– subunits linked together via a Ba2+ cation. The [AsW 11 O 37 (pzdc) 2 ]9– subunit is fused together by a trivacant [AsW 9 O 33 ]9– fragment and two {WO 2 (pzdc)} groups. And the [Ba(AsW 9 O 33) 2 ]16– subunit can be simplified into the ferrocene-like structure. What is particularly interesting is that one N and one O atom of the pzdc2– ligand can directly chelate with the W atom to construct the infrequent W–O–C–C–N five-membered ring. Compound 1 exhibits good proton conduction property with the conductivity of 1 can reach up to 2.37× 10–3 S cm-1 at 70 °C under 95% relative humidity. Synopsis A pzdc2− ligand covalently functionalized arsenotungstate, K 5 Ba 5 H{Ba[AsW 11 O 37 (pzdc) 2 ] 2 }·22H 2 O, consisted of two ancient official cap-shaped polyanion [AsW 11 O 37 (pzdc) 2 ]9− linked via a Ba2+ cation, which exhibits decent proton conduction property with conductivity of 2.37× 10−3 S cm−1 at 70 °C under 95% relative humidity. [Display omitted] [ABSTRACT FROM AUTHOR]