Syntheses And Structures Of Three Organic-Inorganic Hybrids With Different 2d Structural Types Constructed From Rare Earth Polymers And Keggin-Type Silicotungstates

Three organic-inorganic hybrid materials, namely [RE(H2O)(3)K(H2O)(2) (pddc)(2)](2)H-4[SiW12O40]center dot 2H(2)O (RE = Pr (1), Nd (2); H(2)pddc = 3,4-pyridine dicarboxylic acid) and [Y(pzdc)(H2O)(3)](2)H-2[SiW12O40]center dot 4H(2)O (3) (H(2)pzdc = 2,3-pyrazine dicarboxylic acid) have been synthesized and characterized by elemental analyses, IR spectra, UV spectra, TG analyses and X-ray crystallography. Single crystal X-ray analyses reveal that 1-3 all exhibit 2D layer structures. Interestingly, 1 and 2 are isostructural differenting from 3. In 3, the polyoxoanions [SiW12O40](4-) connect the rare earth cations [Y(pzdc)(H2O)(3)](2+) via Y-O bonds forming a (4, 4)-connected 2D topology net with Schlafli symbol of 3(2).6(2).7(2).