Reaction controlled assemblies of polyoxotungstates (-molybdates) and coordination polymers

To investigate the influence of reaction conditions on the compound structures, five polyoxometalate (POM)-supported inorganic-organic hybrid compounds, [Cu(I)(3)(L(1))(4)][PW(12)O(40)] (1), [Cu(I)(3)(L(1))(4)][PMo(12)O(40)] (2), [Cu(I)(3)(L(1))(4)][PW(12)O(40)] (3), [Cu(I)(3)(L(1))(3)][PW(12)O(40)] (4), and [Cu(I)(3)(L(2))(3)][PMo(12)O(40)] (5) [L(1) = 1,4-bis(pyrazol-1-ylmethyl)benzene, L(2) = 4,4'-bis(pyrazol-1-ylmethyl)biphenyl], were hydrothermally synthesized by tuning the reactant species and molar ratio and reaction temperature and were characterized by elemental analysis, IR spectroscopy, PXRD, XPS, electrochemistry, SPS, and X-ray crystallography. Compounds 1 and 2 were synthesized in the isostructural state at 150 degrees C, in which L(1) ligands link Cu(I) ions, generating a cationic 2D 6(3) (hcb) skeleton {[Cu(3)(L(1))(4)](3+)}(n)-like sheet that further connects with POM anions, forming a neutral 2D (3,4)-connected network with a Schlafli symbol of (5(3))(2)(5(4);8(2)). In contrast, compound 3 was synthesized at a relatively lower reaction temperature (130 degrees C) than that for the synthesis of 1 and 2, which exhibits a similar 2D sheet-like cationic skeleton with 1 and 2. Interestingly, the POM anions do not coordinate with the cationic moieties in 3. Compounds 4 and 5 were synthesized with a relatively lower reactant molar ratio in comparison with that for the synthesis of 1-3, in which the cationic coordination moieties all present 1D chain-like structures. Compound 4 exhibits a 3D (3,4)-connected sqc74 framework with a Schlafli symbol of (6;8(2))(6(4);8;10) formed by the POM anions linking {[Cu(3)(L(1))(3)](3+)}(n) cationic chains. In comparison to 4, compound 5 shows a 3D supramolecular framework, which is formed by POM anions and {[Cu(3)(L(2))(3)](3+)}(n) cationic chains via hydrogen bonds. The structural difference of compounds 1-5 indicates that the reaction conditions perform a crucial influence on the structures of this series. The electrochemical properties of 2 and 5 and the SPS responses of 3-5 suggest that these compounds can be used as potential electrocatalytic or photocatalytic framework materials. In addition, EFISPS curves indicate that 3-5 possess the n-type semiconductor characteristic.