Coordination Chemistry of the Hexavacant Tungstophosphate [H2P2W12O48]12− with FeIII Ions: Towards Original Structures of Increasing Size and Complexity

Godin, Béatrice; Chen, Ya-Guang; Vaissermann, Jacqueline; Ruhlmann, Laurent; Verdaguer, Michel; Gouzerh, Pierre

doi:10.1002/anie.200463033

Cited by 187 publications

(92 citation statements)

References 44 publications

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“…(1) consists of two {(B-b-Si-W 9 O 33 (OH))(b-SiW 8 O 29 7 ]·36 H 2 O (2), a {g-SiW 10 (q av(Co-L-Co) = 99.18) than in 1 (q av(Co-LCo) = 92.88). Weaker ferromagnetic interactions were found in 2 than in 1, in agreement with larger Co-L-Co angles in 2.…”

Section: A C H T U N G T R E N N U N G (Oh))(b-siw 8 O 29 -A C H T U mentioning

confidence: 98%

“…[6] On the other hand, the in-situ reaction of multilacunary monomeric polyanions with paramagnetic cations can lead to oligomeric high-nuclearity species. This is generally achieved by acid-base condensation, [7] but supramolecular assemblies around small anions such as halides can also be effective. [8] Recently, insertion into paramagnetic polyoxometalate matrices of exogenous ligands and especially that of the azido anion [9] has shown that such polydentate ligands can also allow the assembly of magnetic polyoxometalate subunits, [10] but in addition could impose ferromagnetic interactions within the cluster.…”

Section: A C H T U N G T R E N N U N G [(A-a-siw 9 O 34 )A C H T U N mentioning

confidence: 99%

“…Few polyoxometalates containing bridging carboxylato ligands have been reported. [7,32] Moreover, 3 and 4 represent rare cases of tetranuclear complexes capping a Keggin-type polyanion, [33] but the {Co 4 O 9 L 3 -A C H T U N G T R E N N U N G (CH 3 COO) 3 } tetrahedral cluster can be compared with the {Ni 4 …”

mentioning

confidence: 99%

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Effect of Cyanato, Azido, Carboxylato, and Carbonato Ligands on the Formation of Cobalt(II) Polyoxometalates: Characterization, Magnetic, and Electrochemical Studies of Multinuclear Cobalt Clusters

Lisnard

Mialane

Dolbecq

et al. 2007

Chemistry A European J

183

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Five Co(II) silicotungstate complexes are reported. The centrosymmetric heptanuclear compound K(20)[{(B-beta-SiW(9)O(33)(OH))(beta-SiW(8)O(29)(OH)(2))Co(3)(H(2)O)}(2)Co(H(2)O)(2)]47 H(2)O (1) consists of two {(B-beta-SiW(9)O(33)(OH))(beta-SiW(8)O(29)(OH)(2))Co(3)(H(2)O)} units connected by a {CoO(4)(H(2)O)(2)} group. In the chiral species K(7)[Co(1.5)(H(2)O)(7))][(gamma-SiW(10)O(36))(beta-SiW(8)O(30)(OH))Co(4)(OH)(H(2)O)(7)]36 H(2)O (2), a {gamma-SiW(10)O(36)} and a {beta-SiW(8)O(30)(OH)} unit enclose a mononuclear {CoO(4)(H(2)O)(2)} group and a {Co(3)O(7)(OH)(H(2)O)(5)} fragment. The two trinuclear Co(II) clusters present in 1 enclose a mu(4)-O atom, while in 2 a mu(3)-OH bridging group connects the three paramagnetic centers of the trinuclear unit, inducing significantly larger Co-L-Co (L=mu(4)-O (1), mu(3)-OH (2)) bridging angles in 2 (theta(av(Co-L-Co))=99.1 degrees ) than in 1 (theta(av(Co-L-Co))=92.8 degrees ). Weaker ferromagnetic interactions were found in 2 than in 1, in agreement with larger Co-L-Co angles in 2. The electrochemistry of 1 was studied in detail. The two chemically reversible redox couples observed in the positive potential domain were attributed to the redox processes of Co(II) centers, and indicated that two types of Co(II) centers in the structure were oxidized in separate waves. Redox activity of the seventh Co(II) center was not detected. Preliminary experiments indicated that 1 catalyzes the reduction of nitrite and NO. Remarkably, a reversible interaction exists with NO or related species. The hybrid tetranuclear complexes K(5)Na(3)[(A-alpha-SiW(9)O(34))Co(4)(OH)(3)(CH(3)COO)(3)]18 H(2)O (3) and K(5)Na(3)[(A-alpha-SiW(9)O(34))Co(4)(OH)(N(3))(2)(CH(3)COO)(3)]18 H(2)O (4) were characterized: in both, a tetrahedral {Co(4)(L(1))(L(2))(2)(CH(3)COO)(3)} (3: L(1)=L(2)=OH; 4: L(1)=OH, L(2)=N(3)) unit capped the [A-alpha-SiW(9)O(34)](10-) trivacant polyanion. The octanuclear complex K(8)Na(8)[(A-alpha-SiW(9)O(34))(2)Co(8)(OH)(6)(H(2)O)(2)(CO(3))(3)]52 H(2)O (5), containing two {Co(4)O(9)(OH)(3)(H(2)O)} units, was also obtained. Compounds 2, 3, 4, and 5 were less stable than 1, but their partial electrochemical characterization was possible; the electronic effect expected for 3 and 4 was observed.

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Section: A C H T U N G T R E N N U N G (Oh))(b-siw 8 O 29 -A C H T U mentioning

confidence: 98%

Section: A C H T U N G T R E N N U N G [(A-a-siw 9 O 34 )A C H T U N mentioning

confidence: 99%

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Effect of Cyanato, Azido, Carboxylato, and Carbonato Ligands on the Formation of Cobalt(II) Polyoxometalates: Characterization, Magnetic, and Electrochemical Studies of Multinuclear Cobalt Clusters

Lisnard

Mialane

Dolbecq

et al. 2007

Chemistry A European J

183

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“…However, to our knowledge, only one example of an iron-containing POM system synthesized under hydrothermal conditions, a [PW 12 O 40 ] 3À ion with a {Fe II A C H T U N G T R E N N U N G (phen) 2 A C H T U N G T R E N N U N G (H 2 O)} group, has been reported, [14] while the synthesis of iron-based POM materials has been extensively explored under normal bench conditions. These multi-iron complexes exhibit spectacular structures [3] and appealing magnetic [15] or electrochemical properties; [16] they are also interesting because of their catalytic properties, [17] including biomimetic catalysis. Indeed, POMs can be seen as rigid polydentate ligands with electron-acceptor properties similar to the active sites of natural enzymes.…”

Section: Introductionmentioning

confidence: 99%

“…[W 6 6À ), [1] although POMs with new topological arrangements are still being discovered. [2] Lacunary polyoxotungstates act as ligands that can bind to 3d transition-metal ions giving rise to species containing transition-metal clusters with nuclearities from 1 to 28 [3] and exhibiting appealing properties particularly in the fields of molecular magnetism [4] and catalysis. [5] Furthermore, the incorporation of exogeneous ligands bridging the paramagnetic centers allows the magnetic coupling between the transition-metal ions encapsulated within the POM to be modulated.…”

Section: Introductionmentioning

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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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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PolyoxometalatesUpdate based on the original article by Michael T. Pope,Encyclopedia of Inorganic Chemistry© 2005, John Wiley & Sons, Ltd.

Pope¹,

Kortz²

2012

Encyclopedia of Inorganic and Bioinorganic Chemistry

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The class of complexes known as polyoxometalates (POMs) is predominantly populated by polyoxoanions of high‐valent (d 0 , d 1 ) transition metals of groups 5 and 6 that typically incorporate some 5‐50 metal centers in structures of high symmetry. In most cases, the metal atoms occupy {MO 6 } octahedra that share vertices and edges. However, recent reports of POMs that incorporate square‐planar {Pd II O 4 } and hexagonal‐bipyramidal {U VI O 2 (η 2 − O 2 ) 2 (OH) 2 } building blocks indicate that further expansion of the field is in progress. The descriptive chemistry of many polyoxomolybdates and polyoxotungstates dates from the last third of the nineteenth century but it was not until the mid‐twentieth century that structural principles and the aqueous equilibria controlling the formation of POMs from monomeric oxoanions began to be recognized and quantified. That additional heteroatoms (metallic or nonmetallic) can be incorporated into the structures of, especially, polymolybdates and tungstates accounts for the enormous and rapidly developing variety of structures and possible applications of POMs. Four general types of POM structure, based on the mode of incorporation of the heteroatom(s), are described and it is shown how these can lead to hybrid organo‐POM complexes and to functionalization of POMs. Certain POM structures are reducible to mixed‐valence “heteropoly blue” versions, and those incorporating domains of paramagnetic heteroatoms can exhibit single‐molecule magnetic properties. The possibility that Mo VI and W VI can occupy a seven‐coordinate {O = M(O 6 )} polyhedron in POMs was first observed in [Mo 36 O 112 (H 2 O) 8 ] 8− {Mo 36 }; subsequent work has led to the development of other macrosized POMs including rings {Mo 154 }, hollow icosahedral “Keplerates” {Mo 60 W 72 }, and the “blue hedgehog” {Mo 368 }. Aqueous and aqueous‐organic solutions of such macro‐POMs spontaneously form hollow spherical vesicular structures (“blackberries”) with diameters typically 90 nm, with inter‐POM separations of 1 nm, depending upon the dielectric constant of the solvent. The various properties of POMs (such as large size, high molecular weight, solubility in polar and nonpolar solvents, electron and proton transfer and storage capacity, high thermal stability) have sparked applications in several fields, most notably in catalysis, both heterogeneous and homogeneous. Other applications include their use as electron‐dense staining and imaging agents, and their antiviral and antitumoral activity. Unconventional POMs are mainly represented by polyoxopalladates(II) and polyperoxodioxouranates(VI), which are also isolated from aqueous media. Unlike the early transition‐metal‐based POMs, the palladate structures are terminated by heteroatom groups and may also contain an internal heteroatom. The class of polyperoxodioxouranates(VI) isolated from more alkaline media frequently have fullerene‐like structures based on hexagonal bipyramidal bipyramids linked by η 2 ‐peroxo groups and hydroxo, oxalato, diphosphato, or diphosphonato bridges.

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Coordination Chemistry of the Hexavacant Tungstophosphate [H₂P₂W₁₂O₄₈]¹²⁻ with Fe^III Ions: Towards Original Structures of Increasing Size and Complexity

Cited by 187 publications

References 44 publications

Effect of Cyanato, Azido, Carboxylato, and Carbonato Ligands on the Formation of Cobalt(II) Polyoxometalates: Characterization, Magnetic, and Electrochemical Studies of Multinuclear Cobalt Clusters

Effect of Cyanato, Azido, Carboxylato, and Carbonato Ligands on the Formation of Cobalt(II) Polyoxometalates: Characterization, Magnetic, and Electrochemical Studies of Multinuclear Cobalt Clusters

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

PolyoxometalatesUpdate based on the original article by Michael T. Pope,Encyclopedia of Inorganic Chemistry© 2005, John Wiley & Sons, Ltd.

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Coordination Chemistry of the Hexavacant Tungstophosphate [H2P2W12O48]12− with FeIII Ions: Towards Original Structures of Increasing Size and Complexity

Cited by 187 publications

References 44 publications

Effect of Cyanato, Azido, Carboxylato, and Carbonato Ligands on the Formation of Cobalt(II) Polyoxometalates: Characterization, Magnetic, and Electrochemical Studies of Multinuclear Cobalt Clusters

Effect of Cyanato, Azido, Carboxylato, and Carbonato Ligands on the Formation of Cobalt(II) Polyoxometalates: Characterization, Magnetic, and Electrochemical Studies of Multinuclear Cobalt Clusters

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

PolyoxometalatesUpdate based on the original article by Michael T. Pope,Encyclopedia of Inorganic Chemistry© 2005, John Wiley & Sons, Ltd.

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Coordination Chemistry of the Hexavacant Tungstophosphate [H₂P₂W₁₂O₄₈]¹²⁻ with Fe^III Ions: Towards Original Structures of Increasing Size and Complexity

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