Spectroscopic properties of neodymium(III)-containing polyoxometalates in aqueous solution

The spectroscopic properties of the neodymium(III)-containing polyoxometalates (POMs) [Nd(PW11O39)2]11−, [Nd(PMo2W9O39)2]11−, [Nd(PMo4W7O39)2]11−, [Nd(PMo6W5O39)2]11−, [Nd(SiMo2W9O39)2]13−, [Nd(P2W17O61)2]17−, [NdW10O36]9−, [NdP5W30O110]12− and [NdAs4W40O140]25− are described. Absorption spectra of aqueous solutions of the complexes have been recorded and the transition intensities are parameterised in terms of the Judd-Ofelt intensity parameters Ωλ (λ = 2, 4, 6). Marked differences were found between the luminescence lifetimes of the complexes of the type Nd(POM) and those of the type Nd(POM)2, due to a better shielding of the neodymium(III) ions from the bulk water molecules in the latter type of complexes.