A new Wells-Dawson organic-inorganic hybrid polytungstate containing dimeric silver coordination complexes: (Hpy)2[Ag2(phen)4]2(P2W18O62)

An effective route led to incorporating Ag+ and reductive pyridine simultaneously into a polytungstate, which contains an uncommon dimeric Ag-coordination complex and mixed organic-ingredients. An attempt to incorporate Ag+ ions and some organic-reducing ingredients (e. g. pyridine) simultaneously into a polyoxometalate is a challenging task due to the high-standard reduction potential of Ag+ ions. By using a second organic ligand to coordinate Ag+ first, we prepared a new polytungstate, (Hpy)(2)[Ag-2(phen)(4)](2)(P2W18O62) (1) (py = pyridine (C5NH5), phen = 1,10-phenanthroline (C12N2H8)), which contains discrete inorganic polyanions ([P2W18O62](6-)), protonated pyridine molecules, and [Ag-2(phen)(4)](2+) dimers. The isolated inorganic polyanions cluster close to the planes of (1 0 0) and are bound together by pyridine molecules via hydrogen bonds to form layers parallel to (1 0 0) at (0, y, z) and (0.5, y, z). The [Ag-2(phen)(4)](2+) dimers are located between successive layers of (1 0 0) and represent an uncommon feature that the hexagonal benzene rings of phen molecules are directly overlapped face to face. Our work opens a new way for synthesis of other Wells-Dawson organic-inorganic hybrid polytungstates by controlling reactant addition order.