Self-Assembly of a Series of Extended Architectures Based on Polyoxometalate Clusters and Silver Coordination Complexes

Three unusual compounds based on polyoxometalate building blocks, [(H₂O)₅Na₂(C₆NO₂H₄)(C₆NO₂H₅)₃Ag₂][Ag₂IMo₆O₂₄(H₂O)₄]·6.25H₂O (1), [(H₂O)₄Na₂(C₆NO₂H₅)₆Ag₃][IMo₆O₂₄]·6H₂O (2), and (C₆NO₂H₆)₂[(C₆NO₂H₅)₂Ag][Cr(OH)₆Mo₆O₁₈]·4H₂O (3), have been synthesized and characterized by elemental analysis; IR, XPS, and ESR spectroscopy; TG analysis; and single-crystal X-ray diffraction. Compound 1 is constructed from the cationic two-dimensional (2D) coordination polymer sheets which are constituted of [(H₂O)₅Na₂(C₆NO₂H₄)(C₆NO₂H₅)₃Ag₂]³⁺ and anionic [Ag₂IMo₆O₂₄(H₂O)₄]^3- chains as pillars, forming a three-dimensional (3D) supramolecular framework via weak Ag−O interactions. Compound 2 is composed of the well-defined [IMo₆O₂₄]^5- building blocks, which are linked through trinuclear Ag-pyridine-3-carboxylic acid, [(C₆NO₂H₅)₆Ag₃]³⁺, fragments into a one-dimensional (1D) hybrid chain; adjacent chains are further connected by sodium cations to yield a novel 2D network. Compound 3 has a 1D chainlike structure constructed from [Cr(OH)₆Mo₆O₁₈]^3- building blocks and Ag-pyridine-4-carboxylic acid coordination units. The crystal data for these compounds are the following:  1, triclinic, P1̄, a = 13.280(3) Å, b = 13.641(3) Å, c = 16.356(3) Å, α = 89.68(3)°, β = 88.31(3)°, γ = 75.87(3)°, Z = 2; 2, triclinic, P1̄, a = 11.978(2) Å, b = 12.008(2) Å, c = 13.607(3) Å, α = 116.14(3)°, β = 108.85(3)°, γ = 93.86(3)°, Z = 1; 3, triclinic, P1̄, a = 10.458(2) Å, b = 10.644(2) Å, c = 12.295(3) Å, α = 97.40(3)°, β = 112.38(3)°, γ = 113.59(3)°, Z = 1.