Three new organic–inorganic hybrids based on Keggin ions and aminopyridine: Crystal structure and catalytic property

Abstract Three new organic–inorganic supramolecular hybrids, namely, (2-C 5 H 7 N 2 ) 4 (PMo 12 O 40 ) 2 ·(2-C 5 H 6 N 2 ) 6 ·(C 4 H 8 N 4 )·H 2 O (compound 1 ), (3-C 5 H 7 N 2 ) 6 ·(PMo 12 O 40 ) 2 ·(3-C 5 H 6 N 2 ) 4 ·H 8 O 4 ·(H 2 O) 8 (compound 2 ), (4-C 5 H 7 N 2 ) 6 (PMo 12 O 40 ) 2 ·(4-C 5 H 6 N 2 ) 4 ·(C 4 H 6 N 3 ) (compound 3 ), have been synthesized by hydrothermal method and characterized by elemental analyses, IR, UV–vis, TGA and single-crystal X-ray diffraction. Compound 1 – 3 constructed from Keggin polyoxoanions and 2-/3-/4-aminopyridine organic ligands, exhibit an extended three-dimensional supramolecular network via hydrogen bonding and π – π stacking interactions, while compound 2 contains a tetramolecular water clusters. compounds 1 and 3 have a higher catalytic activity for the oxidation of acetone tested in a continuous-flow fixed-bed micro-reactor. When the initial concentration of the acetone is 6.1 g m −3 in air and the flow velocity is 4.5 mL min −1 , the acetone is completely eliminated at 160 °C. But compound 2 has lower catalytic activity for the oxidation of acetone.