Isomeric effects of Al ₁₃ Keggin clusters as catalyst support on oxidation reactions

Ionic crystals were synthesized by combining a catalytically active polyoxometalate [Al(OH)₆Mo₆O₁₈]^3- with Keggin-type [Al₁₃O₄(OH)₂₄(H₂O)₁₂]⁷⁺ isomers (ε-Al₁₃ or δ-Al₁₃) serving as catalyst supports. The influence of the Al₁₃ isomers on catalytic activity in sulfide oxidation was systematically investigated. The ionic crystal containing δ-Al₁₃ exhibited superior catalytic performance, which was attributed to stronger interactions with sulfide substrates, as evidenced by solid-state NMR measurements. These findings highlight that exploiting Al₁₃ structural isomers provides a novel strategy to the design and synthesis of supported catalysts.