dl-Alanine Covalently Bonded Giant Arsenotungstate with Rapid Photochromic and Decent Proton Conduction Properties

Abstract

A dl-alanine covalently bonded giant arsenotungstate, namely, Na₃Ba₁₁H₁₆[(AsW₉O₃₃)₆{W₂O₅(H₂O)(dl-Ala)}₂{W₃O₆(H₂O)(dl-Ala)}₂{W₂O₅(dl-Ala)}] (1; dl-Ala = dl-alanine), has been synthesized and is composed of six [AsW₉O₃₃]^9- fragments fused together via two [W₂O₅(H₂O)(dl-Ala)]⁺ segments, two [W₃O₆(H₂O)(dl-Ala)]⁵⁺ segments, and a [W₂O₅(dl-Ala)]⁺ segment. This complex represents the first carboxylate-based hybrid polyoxotungstate without the introduction of lanthanide ions. Besides, compound 1 demonstrates not only fast photochromic properties but also interesting proton conductivity properties, with an achieved conductivity of 2.830 × 10^-4 S·cm^-1 (65 °C, 75% relative humidity).