Synthesis, crystal structure and characterization of a series of complexes constructed from coordinated Lanthanides(III) and the heteropolyanion [SiMo12O40]4−

Abstract

The reaction of α-[SiMo12O40]4− with trivalent cations Ln3+ and N-methyl-2-pyrrolidone leads to a series of complexes of formula [Ln(NMP)4(H2O) n ]H[SiMo12O40] · 2NMP · mH2O [where Ln = La (1), Pr (2), Nd (3), Sm (4), Gd (5), n = 4, Ln = Dy (6), Er (7), n = 3. NMP = N-methyl-2-pyrrolidone]. The syntheses, X-ray crystal structures, IR, and ESR spectra and thermal properties of the complexes 1, 2, 4, 6, 7 have been reported previously. Here, we report X-ray crystal structures, IR, UV, ESR spectra and thermal properties of the complexes [Nd(NMP)4(H2O)4]H[SiMo12O40] · 2NMP · 1.5H2O (3), and [Gd(NMP)4(H2O)4]H[SiMo12O40] · 2NMP · H2O (5). In addition, the electrochemical behaviour of this series of complexes in aqueous solution and aqueous-organic solution has been investigated and systematic comparisons have been made. All these complexes exhibit successive reduction process of the Mo atoms.