The construction of a new POMs-based inorganic–organic hybrid framework involving in-situ ligand conversion from 1,3-bis(4-pyridyl)propane to isonicotinic acid

A new inorganic–organic hybrid complex, Na2[{Ag10(NC5H4COO)8(H2O)6}(SiW12O40)] (1), has been successfully synthesized from [SiW12O40]4− anions, Ag+ ions and 1,3-bis(4-pyridyl)propane under hydrothermal conditions and characterized by elemental analyses, IR spectroscopy, TG analyses, and single-crystal X-ray diffraction. In complex 1, each [SiW12O40]4− anion connects with six Ag atoms and in turn each Ag atom links to three [SiW12O40]4− anions, leading to a (6, 3) layer. Such (6, 3) layers are arranged in parallel and further linked by [Ag(H2O)(NC5H4COOH)2]− fragments to generate a 3D framework. The most striking feature in this work is that 1,3-bis(4-pyridyl)propane converses to isonicotinic acid in the synthetic reaction of 1, which may be induced by the combined function of Ag+ ion and polyoxometalate.