Polyoxometalate templated silver-bisphosphine sandwich: structurally tunable hybrid materials

Abstract

Organic macrocyclic complexes composed of polyoxometalates (POMs) and cyclodextrins based on host–guest interactions have garnered significant attention. Herein, we report the assemblies by blending inorganic POMs and a complex macrocycle. Utilizing silver-coordinated bridge connections, four distinct POM-based silver-bisphosphine (Ag₂dppp₂) (dppp = 1,3-bis(diphenylphosphino)propane) macrocyclic hybrids: [Ag₄(dppp)₄(Mo₈O₂₆)] (1), {[Ag₄(dppp)₄(PW₁₂O₄₀)]NO₃} (2), [Ag₃(dppp)₃(PMo₁₂O₄₀)] (3), and [Ag₂(dppp)₂(CH₃CN)₂(Mo₆O₁₉)] (4) have successfully been synthesized. The self-assemblies of hybrids involve sandwich and tubular structures that depend on the size, charge of POMs, anions and coordination solvent. Interactions of the silver-bisphosphine macrocycle and POMs in solution were further examined by ³¹P nuclear magnetic resonance (NMR) and cyclic voltammetry (CV). Dye adsorption behavior has been investigated for the structure–activity relationship of surface structures of the hybrids.