Preparation and characterization of iron(III)- and rhodium(III)-containing heteropolytungstates. Identification of novel oxo-bridged iron(III) dimers

Zonnevijlle, F.; Tourné, Claude M.; Tourné, Gilbert F.

doi:10.1021/ic00137a042

Cited by 148 publications

(85 citation statements)

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“…[22] The splitting in complex 4 is thus close to the largest splittings observed in the family of monosubstituted lacunary derivatives. The splitting in complex 2 is more along the order of the values reported for [PW 11 O 39 Fe [23] and the splitting in complex 1 is close to the zero splitting value of the saturated [PW 12 O 40 ] 3À anion. The increasing value of Dn from complexes 1 to 4 can be tentatively explained by weaker interactions between the metal and the POM as shown by the significant elongation of the FeÀOA C H T U N G T R E N N U N G (PO 3 ) bond from complex 1 to complex 4 ( Table 1, see also the structural description below).…”

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confidence: 59%

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Fe₂ and Fe₄ Clusters Encapsulated in Vacant Polyoxotungstates: Hydrothermal Synthesis, Magnetic and Electrochemical Properties, and DFT Calculations

Dolbecq

Marrot

Rivière

et al. 2008

Chemistry A European J

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While the reaction of [PW(11)O(39)](7-) with first row transition-metal ions M(n+) under usual bench conditions only leads to monosubstituted {PW(11)O(39)M(H(2)O)} anions, we have shown that the use of this precursor under hydrothermal conditions allows the isolation of a family of novel polynuclear discrete magnetic polyoxometalates (POMs). The hybrid asymmetric [Fe(II)(bpy)(3)][PW(11)O(39)Fe(2) (III)(OH)(bpy)(2)]12 H(2)O (bpy=bipyridine) complex (1) contains the dinuclear {Fe(micro-O(W))(micro-OH)Fe} core in which one iron atom is coordinated to a monovacant POM, while the other is coordinated to two bipyridine ligands. Magnetic measurements indicate that the Fe(III) centers in complex 1 are weakly antiferromagnetically coupled (J=-11.2 cm(-1), H=-JS(1)S(2)) compared to other {Fe(micro-O)(micro-OH)Fe} systems. This is due to the long distances between the iron center embedded in the POM and the oxygen atom of the POM bridging the two magnetic centers, but also, as shown by DFT calculations, to the important mixing of bridging oxygen orbitals with orbitals of the POM tungsten atoms. The complexes [Hdmbpy](2)[Fe(II)(dmbpy)(3)](2)[(PW(11)O(39))(2)Fe(4) (III)O(2)(dmbpy)(4)]14 H(2)O (2) (dmbpy=5,5'-dimethyl-2,2'-bipyridine) and H(2)[Fe(II)(dmbpy)(3)](2)[(PW(11)O(39))(2)Fe(4) (III)O(2)(dmbpy)(4)]10 H(2)O (3) represent the first butterfly-like POM complexes. In these species, a tetranuclear Fe(III) complex is sandwiched between two lacunary polyoxotungstates that are pentacoordinated to two Fe(III) cations, the remaining paramagnetic centers each being coordinated to two dmbpy ligands. The best fit of the chi(M)T=f(T) curve leads to J(wb)=-59.6 cm(-1) and J(bb)=-10.2 cm(-1) (H=-J(wb)(S(1)S(2)+S(1)S(2*)+S(1*)S(2)+S(1*)S(2*))-J(bb)(S(2)S(2*))). While the J(bb) value is within the range of related exchange parameters previously reported for non-POM butterfly systems, the J(wb) constant is significantly lower. As for complex 1, this can be justified considering Fe(w)--O distances. Finally, in the absence of a coordinating ligand, the dimeric complex [N(CH(3))(4)](10)[(PW(11)O(39)Fe(III))(2)O]12 H(2)O (4) has been isolated. In this complex, the two single oxo-bridged Fe(III) centers are very strongly antiferromagnetically coupled (J=-211.7 cm(-1), H=-JS(1)S(2)). The electrochemical behavior of compound 1 both in dimethyl sulfoxide (DMSO) and in the solid state is also presented, while the electrochemical properties of complex 2, which is insoluble in common solvents, have been studied in the solid state.

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confidence: 59%

“…[31] The dimerization of transition-metal mono-substituted POMs has also been studied for the titanium (in organic medium), [32] zirconium [33] and ruthenium [34] derivatives, but the structural characterization of a m-oxo bridged dimer has only very recently been performed in the case of [{SiW 11 O 39 Ru IV } 2 O] 10À .…”

mentioning

confidence: 99%

Fe₂ and Fe₄ Clusters Encapsulated in Vacant Polyoxotungstates: Hydrothermal Synthesis, Magnetic and Electrochemical Properties, and DFT Calculations

Dolbecq

Marrot

Rivière

et al. 2008

Chemistry A European J

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“…[54] Unfortunately this work did not exploit the development and use of techniques such as 183 W NMR spectroscopy and relied predominantly upon elemental analyses, electronic spectroscopy, and titrimetry. It was concluded that the aqua ligand on rhodium could be deprotonated to produce the hydroxo and oxo derivatives which were isolated and analyzed.…”

Section: Rhodiummentioning

confidence: 99%

Noble Metals in Polyoxometalates

2012

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Polyoxometalates containing noble metal ions, such as ruthenium, osmium, rhodium, palladium, platinum, silver and gold, are a structurally diverse class of compounds. They include both classical heteropolyanions (vanadates, molybdates, tungstates) in which noble metals are present as heteroatoms, as well as the recently discovered class of polyoxometalates with noble metal "addenda" atoms. The focus of this Review is on complexes that should, in principle, exist as discrete molecular species in solution, and which are therefore of interest for their reactivity, their future synthetic utility and potential applications, for example, in catalysis or nanoscience.

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“…The shoulder band due to the O to Fe 3+ charge transfer [39] was observed around 450 nm (ε = 98 M −1 ·cm −1 ). This spectrum was similar to that of α,α-Fe4-open ( Figure S3).…”

Section: Absorption Spectrummentioning

confidence: 99%

β,β-Isomer of Open-Wells–Dawson Polyoxometalate Containing a Tetra-Iron(III) Hydroxide Cluster: [{Fe4(H2O)(OH)5}(β,β-Si2W18O66)]9−

et al. 2016

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Preparation and characterization of iron(III)- and rhodium(III)-containing heteropolytungstates. Identification of novel oxo-bridged iron(III) dimers

Cited by 148 publications

References 1 publication

Fe₂ and Fe₄ Clusters Encapsulated in Vacant Polyoxotungstates: Hydrothermal Synthesis, Magnetic and Electrochemical Properties, and DFT Calculations

Fe₂ and Fe₄ Clusters Encapsulated in Vacant Polyoxotungstates: Hydrothermal Synthesis, Magnetic and Electrochemical Properties, and DFT Calculations

Noble Metals in Polyoxometalates

β,β-Isomer of Open-Wells–Dawson Polyoxometalate Containing a Tetra-Iron(III) Hydroxide Cluster: [{Fe4(H2O)(OH)5}(β,β-Si2W18O66)]9−

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Preparation and characterization of iron(III)- and rhodium(III)-containing heteropolytungstates. Identification of novel oxo-bridged iron(III) dimers

Cited by 148 publications

References 1 publication

Fe2 and Fe4 Clusters Encapsulated in Vacant Polyoxotungstates: Hydrothermal Synthesis, Magnetic and Electrochemical Properties, and DFT Calculations

Fe2 and Fe4 Clusters Encapsulated in Vacant Polyoxotungstates: Hydrothermal Synthesis, Magnetic and Electrochemical Properties, and DFT Calculations

Noble Metals in Polyoxometalates

β,β-Isomer of Open-Wells–Dawson Polyoxometalate Containing a Tetra-Iron(III) Hydroxide Cluster: [{Fe4(H2O)(OH)5}(β,β-Si2W18O66)]9−

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Fe₂ and Fe₄ Clusters Encapsulated in Vacant Polyoxotungstates: Hydrothermal Synthesis, Magnetic and Electrochemical Properties, and DFT Calculations

Fe₂ and Fe₄ Clusters Encapsulated in Vacant Polyoxotungstates: Hydrothermal Synthesis, Magnetic and Electrochemical Properties, and DFT Calculations