An open chain carboxyethyltin functionalized sandwich-type tungstophosphate based on a trivacant Dawson subunit: synthesis, characterization and properties

Abstract

A Dawson sandwich-type polyoxometalate {C(NH₂)₃}₁₂H₄[αββα-{(Sn(C₃H₄O₂))₂Mn₂(P₂W₁₅O₅₆)₂}]·22H₂O (abbreviated as SnR-Mn-P₂W₁₅), functionalized by open chain carboxyethyltin groups, was first prepared in aqueous solution under conventional reaction conditions, and then structurally characterized by physicochemical and spectroscopic methods. Single crystal X-ray diffraction analysis revealed that two Mn²⁺ cations and two [Sn(CH₂CH₂COO)]²⁺ groups are located in the internal and external positions in the so-called equatorial region of SnR-Mn-P₂W₁₅, respectively. Intriguingly, two exposed carboxyl groups act as stretching-arm brackets, which provide a favorable structure for potential further functionalization. The electrocatalytic activity of SnR-Mn-P₂W₁₅ towards the reduction of hydrogen peroxide and nitrite was studied. Additionally, its acid catalysis and oxidation catalysis activities in organic synthesis were investigated.