Rational approach of the stoichiometries of lanthanide complexes with α2-[P2W17O61]10− heteropolytungstate in aqueous solution

Influence of Steric and Electronic Properties of the Defect Site, Lanthanide Ionic Radii, and Solution Conditions on the Composition of Lanthanide(III) α1-P2W17O6110- Polyoxometalates

“…A few studies report stability constants (conditional and thermodynamic) for Ln complexes of α 2 -P 2 W 17 O 61 10- . These studies suggest that K 1 and K 2 remain constant over the series ,, or increase slightly from La to Eu and remain constant from the mid to late lanthanides . Generally, the thermodynamic log K 1 and log K 2 are on the order of 10.35−12.7 and 6−8.1, respectively, and log K 1 /log K 2 are ca.…”

Production and Reactions of Organic-Soluble Lanthanide Complexes of the Monolacunary Dawson [α1-P2W17O61]10-Polyoxotungstate

“…The most important equilibria are summarized in Scheme . Similar solution equilibria have been investigated for complexes with the isomeric [α 2 -P 2 W 17 O 61 ] 10- . ,−

1

…”

“…Another approach to the synthesis of lanthanide polyoxometalate materials is the reaction of plenary or polylacunary POMs with lanthanides. Plenary POMs can weakly coordinate other metal ions; indeed, solid-state materials can be obtained from these building blocks and lanthanide ion linkers. − The lacunary polyoxometalates form strong complexes with transition metals and lanthanides. − Large assemblies have been obtained with polylacunary POMs and lanthanides because of the large number of basic oxygens in these POMs and the high coordination number requirement of lanthanide ions. − The strategy to use lanthanides as “linkers” to form nanomaterials has not yet proven positive for production of luminescent or catalytic materials probably because the lanthanide center is often (1) highly hydrated, leading to quenching in the case of luminescence, or (2) highly coordinated to other POM ligands that will neither produce effective sensitization nor allow substrates to enter the Ln coordination sphere, in the case of catalytic applications.…”

“…Similar solution equilibria have been investigated for complexes with the isomeric [R 2 -P 2 W 17 O 61 ] 10-. 24,[36][37][38][39] In all of these complexes, the Ln(III) ion occupies the lacuna of [R 1 -P 2 W 17 O 61 ] 10-. As this lacuna provides only four basic oxygen donor atoms, and lanthanides are commonly 8 or 9 coordinated, further coordination sites are available on the lanthanide.…”

Europium(III) Reduction and Speciation within a Wells−Dawson Heteropolytungstate

“…Lanthanide (Ln) interactions with polyoxometalate (POM) anions are of contemporary interest, both fundamentally and practically, as a consequence of the formation of high-nuclearity clusters with complex architectures assembled from oxo linkage connectivities of f and d elements, −Ln(III)−O−M(VI)− for M = Mo and W. – The resulting Ln-POM clusters offer unique functionalities and properties as luminescent materials, particularly the Eu-POMs, , and as selective and recoverable Lewis acid catalysts. , Moreover, prospective and realized applications in areas of separations science, photophysics, and electroanalytical chemistry are founded upon the renown reduction−oxidation (redox) properties of POMs. , As such, the fusion of redox-active Ln ions, specifically the reducible Eu(III) ion and the oxidizable Ce(III) ion, with POMs provides molecular systems with hybrid electrochemical properties, such as seen in other hybrid systems that combine, for example, metallocenes, fullerenes, , and multinuclear exohedral metallofullerenes . For Ln-POMs, the combination of the key electrofunctional properties of both the metal and the ligand in one molecule produces two-center, multielectron redox systems in which basic information about the interactions between the atomic-like Ln f orbitals and the band-like M d orbitals of POM ligands is largely unknown.…”