Self-Assembly of Ln(III)-Containing Tungstotellurates(VI): Correlation of Structure and Photoluminescence.

The generation of five types of Ln(III)-containing tungstotellurates(VI), dimeric (DMAH)12Na2[H10(WO2){Ln(H2O)5(TeW18O65)}2]· nH2O (abbreviated as {Ln2Te2W37}; Ln = Eu, Gd, or Tb; DMAH = dimethylammonium), tetrameric (DMAH)21Na7[H16{Ln(H2O)5(TeW18O64)}4]· nH2O (abbreviated as {Ln4Te4W72}, Ln = Eu or Gd), 2:2 dimeric (DMAH)12[H6{Tb(H2O)3(TeW17O61)}2]·25H2O (abbreviated as {Tb2Te2W34}), 1:1 monosubstituted (DMAH)7Na2[H2Tb(H2O)4(TeW17O61)]·21H2O (abbreviated as {TbTeW17}), and three-dimensional polymer (DMAH)2[HTb(H2O)4{TeW6O24}]·14H2O (abbreviated as {TbTeW6} n), provides insight into the rich condensation chemistry of lacunary and other Dawson-type polyoxometalates. The pH and the type of Ln3+ source both dictate which of these new complexes form. To our knowledge, {Ln4Te4W72} is the highest-nuclearity tungstotellurate to date, and {Tb2Te2W34} and {TbTeW17} contain the first lacunary {TeW17O61}. Electrospray ionization mass spectra analyses indicate that the Dawson-like building blocks, {TeW18O65} and {TeW17O61}, found in solid structures are also present in solution. The intense photoluminescence (characteristic green emission) of {TbTeW6} n, 100× greater than those of {Tb2Te2W37}, {Tb2Te2W34}, and {TbTeW17}, is explained by analysis of all 4 X-ray structures and multiple structure-intensity correlations.