Synthesis, characterization and catalytic activity of a new sandwich-type tungstophosphate functionalized by carboxyethyltin

Reaction of the trivacant Keggin-type tungstophosphate (A-α-Na9PW9O34⋅ 7H2O, abbreviated as {PW9}) with estertin (Cl3Sn(CH2)2COOCH3) in an acetate buffer solution leads to the formation of a new sandwich-type tungstophosphate functionalized by carboxyethyltin, Na3K8[K3{Sn(CH2)2COO}2(A-α-PW9O34)2]·18H2O (1). The title compound was characterized by single crystal X-ray diffraction, elemental analysis, IR, TG, PXRD, 13C, 31P and 119Sn NMR. Structural analysis reveals that the basic skeletal structure of 1 is made up of two [Sn(CH2)2COO]2 + groups and three K+ ions sandwiched by two A-α-[PW9O34]9 − building blocks, which shows the original estertin precursors hydrolyzed into carboxyethyltin. The catalytic activity of 1 has been investigated.