Spectroscopic studies of Eu(III) Keggin's and Dawson's polyoxotungstates substituted by acetato and oxalato ligands

Eu(III) Keggin's and Dawson's type of polyoxometalates (POM) complexes were synthesized and spectroscopically characterized. This work presents results obtained for chosen hybrids of acetato K-12[{Eu(SiMoxW11-xO39)(H2O)}(2)(CH3COO)(2)]center dot nH(2)O, K-16[{Eu(CH3COO)(H2O)(2)(P2W17O61)}(2)]center dot nH(2)O and oxalato (NH4)(29)K-5[{Eu(P2W17O61)}(4)(C2O4)(3)(H2O)(4)]center dot nH(2)O, where x=0, 1. The solid state compositions of the hybrids were characterized by using elemental and ICP-AES analysis, derivatography and FTIR spectroscopy. Luminescence characteristics (intensity, quantum yields, luminescence lifetimes and excitation spectra in the range of the D-5(0) <-- F-7(0) transition) of the synthesized Eu(III) acetato and oxalato complexes were determined in the solid phase and in solution, and they were compared to their parent Eu(III):POM complexes of 1: 1 stoichiometry (ML). (C) 2007 Elsevier B.V. All rights reserved.