“…Although various techniques for functionalization of polyoxometalates have been reported, the synthetic technology of introducing metal ions into vacant sites using lacunary polyoxometalates as inorganic ligands is an effective technique for constructing stable and well-defined active metal centers. In terms of polyoxometalates containing aluminum ions as heteroatoms, various aluminum compounds have been synthesized and structurally characterized [10,11,12,13,14,15,16,17]. Although some aluminum-containing polyoxometalates, e.g., [γ-SiW 10 O 36 {Al(OH 2 )} 2 (μ-OH) 2 ] 4− [10], [(A-PW 9 O 34 ) 2 {W(OH)(OH 2 )}{Al(OH)(OH 2 )}{Al(μ-OH)(OH 2 ) 2 } 2 ] 7− [11], [α-PW 11 {Al(OH 2 )}O 39 ] 4− [11], and [α 2 -P 2 W 17 {Al(OH 2 )}O 61 ] 7− [11], and [Al 4 (H 2 O) 10 (β-AsW 9 O 33 H) 2 ] 4− [12], have been used as Lewis acids and oxidation catalysts, examples of structurally characterized aluminum complexes with polyoxometalate ligands remain rare, and their properties and activities are unknown.…”