Rare-earth-transition-metal organic-inorganic hybrids based on Keggin-type polyoxometalates and pyrazine-2,3-dicarboxylate.
Five rare-earth-transition-metal (RE-TM) heterometal organic-inorganic hybrids based on Keggin-type silicotungstates and mixed ligands H2pzda (pzda=pyrazine-2,3-dicarboxylate) and en (en=ethylenediamine) (enH2)[Cu(en)2(H2O)]2{[Cu(en)2][Cu(en)2(H2O)][(α-SiW11 O39)RE(H2O)(pzda)]}2·n H2O (n≈4; RE=YIII (1), DyIII (2), YbIII (3), and LuIII (4)) and [Cu(en)2(H2O)]2{[Cu(en)2]2[Cu(pzda)2][(α-H2SiW11O39)Ce(H2O)]2}·n H2O (5; n≈8) have been hydrothermally synthesized and structurally characterized. Compounds 1-5 all contain the dimeric mono-RE substituted Keggin [RE(α-SiW11O39)]210- subunits linked by H2pzda ligands. Interestingly, 1-4 exhibit discrete structures, in which the H2pzda ligand acts as a tetradentate ligand to bind the RE and Cu cations, whereas 5 displays a 1D double-chain architecture, in which the H2pzda ligand adopts a new pentadentate mode to connect the Ce and Cu cations. To our knowledge, 1-5 represent the first monovacant Keggin-type silicotungstates containing both RE-TM heterometals and mixed ligands. The luminescence of 2 is derived from the combination of the DyIII cations and H2pzda ligands, whereas the luminescence properties of 1 and 3-5 are attributable to the H2pzda ligands.
Institute of Molecular and Crystal Engineering, School of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan 475004, P. R. China.
Shaowei
S
Zhang
Junwei
J
Zhao
Pengtao
P
Ma
Jingyang
J
Niu
Jingping
J
Wang