One-dimensional mixed-valence Ce(III)/Ce(IV)-containing arsenotungstate for photocatalytic synthesis of quinazolines

A novel mixed-valence cerium-containing polyoxometalate, Na₁₈[Ce(III)₂(H₂O)₁₂Ce(IV)₆(μ₃-O)₄(μ₃-OH)₄(AsW₉O₃₃)₄]·33H₂O (Ce₈As₄W₃₆), was synthesized and characterized. Ce₈As₄W₃₆ is composed of a hexanuclear {Ce(IV)₆O₈} cluster surrounded by four trivacant Keggin-type [AsW₉O₃₃]^9- units. These tetramers are further linked by additional Ce(III) ions to form a one-dimensional chain-like structure, exhibiting hierarchical assembly from discrete clusters to an extended structure. Moreover, Ce₈As₄W₃₆ exhibits remarkable photocatalytic activity for the synthesis of quinazoline derivatives via the cyclization-oxidative aromatization of 2-aminobenzylamines with aldehydes.