Two Keggin sandwich-type tungstophosphates modified by open-chain carboxyethyltin groups and transition metals

Abstract

Two new polyoxometalates containing [PW₉O₃₄]⁹⁻ (abbreviated as PW₉) subunits, carboxyltin groups and transition metal ions, namely K₁₀[Mn₂{Sn(CH₂)₂COO}₂[(B-α-PW₉O₃₄)₂]·14H₂O (1) and Na₈K₂ [Zn₂{Sn(CH₂)₂COO}₂[(B-α-PW₉O₃₄)₂]·13H₂O (2), were successfully assembled in aqueous solutions by a routine synthetic method, and fully characterized. They represent the first single crystal examples of open-chain carboxyethyltin group-modified Keggin sandwich-type tungstophosphates. Their important structural features are two open-chain carboxyethyltin moieties attached on the PW₉ dimer, forming arm-type polyoxometalates. Furthermore, the fluorescence properties, electrocatalytic and oxidation catalytic activities were evaluated. More interestingly, the fluorescence quenching of 1/2-doped TiO₂ was clearly observed, which means that the two compounds may be excellent components of photocatalytic materials.