Synthesis and characterization of two novel high-dimensional extended structures based on Keggin-type polyoxometalates and potassium–glycine complex subunits

Two novel compounds based on Keggin-type polyoxometalates and potassium–glycine coordination complexes, {K2(HGly)2[SiW12O40]}·9H2O 1 and {K3HGly[SiW12O40]}·6H2O 2 (Gly = glycine), have been synthesized and characterized by elemental analyses, IR, TG analyses, cyclic voltammetry and single-crystal X-ray diffraction. Compound 1 is composed of the [α-SiW12O40]4− building blocks, which are linked through potassium–glycine acid fragments to form a novel two-dimensional (2D) network. Compound 2 contains an infinite 2D layer constructed from [SiW12O40]4− building blocks and potassium cations, and adjacent layers are further joined by potassium–glycine complex subunits and potassium cations to yield an unusual three-dimensional (3D) framework. The crystal data for two compounds are the following: 1, monoclinic, space group P21/c, a = 9.829(4) Å, b = 2.477(3) Å, c = 9.777(4) Å, β = 104.80(3)o, V = 4730.7(17) Å3, Z = 4; 2, monoclinic, P2/c, a = 2.777(3) Å, b = 7.529(4) Å, c = 9.219(4) Å, β = 99.60(3)°, V = 4244.2(15) Å3, Z = 4.