Electron‐Sponge Behavior, Reactivity and Electronic Structures of Cobalt‐Centered Cubic Co9Te6(CO)8 Clusters

Bencharif, Mustapha; Cador, Olivier; Cattey, Hélène; Ebner, Alexander; Halet, Jean‐François; Kahlal, Samia; Meier, W.; Mugnier, Yves; Saillard, Jean‐Yves; Schwarz, Patrick; Trodi, Fatima Zohra; Wächter, Joachim; Zabel, Manfred

doi:10.1002/ejic.200701350

Cited by 20 publications

(10 citation statements)

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“…This is probably caused by the close contacts between the reduced sites and the counter cations (Li + ) and by a stabilization of the super-reduced species in a dielectric field of the solid . [PMo 12 O 40 ] 3– can be regarded as a molecular “electron sponge,” although this term has been used for the cobalt telluride clusters which exhibited only a two- or three-electron reduction . Note that the formation of the super-reduced state is probably characteristic of the solid-state electrochemistry of molecular clusters, as an eight-electron reduction occurred for the Mn 12 clusters in the Mn 12 -MCBs .…”

Section: Resultsmentioning

confidence: 99%

In Operando X-ray Absorption Fine Structure Studies of Polyoxometalate Molecular Cluster Batteries: Polyoxometalates as Electron Sponges

et al. 2012

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We carried out in operando Mo K-edge X-ray absorption fine structure measurements on the rechargeable molecular cluster batteries (MCBs) of polyoxometalates (POMs), in which a Keggin-type POM, [PMo(12)O(40)](3-), is utilized as a cathode active material with a lithium metal anode. The POM-MCBs exhibit a large capacity of ca. 270 (A h)/kg in a voltage range between V = 4.0 V and V = 1.5 V. X-ray absorption near-edge structure analyses demonstrate that all 12 Mo(6+) ions in [PMo(12)O(40)](3-) are reduced to Mo(4+) in the discharging process. This means the formation of a super-reduced state of the POM, namely, [PMo(12)O(40)](27-), which stores 24 electrons, and this electron number can explain the large capacity of the POM-MCBs. Furthermore, extended X-ray absorption fine structure analyses reveal the molecular structure of [PMo(12)O(40)](27-), which is slightly reduced in size compared to the original [PMo(12)O(40)](3-) and involves Mo(4+) metal-metal-bonded triangles. Density functional theory calculations suggest that these triangles are formed because of the large number of additional electrons in the super-reduced state.

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Section: Resultsmentioning

confidence: 99%

In Operando X-ray Absorption Fine Structure Studies of Polyoxometalate Molecular Cluster Batteries: Polyoxometalates as Electron Sponges

et al. 2012

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“…Examples can be identified from several well-elucidated structures such as Zr 6 AX 12 (A ) H, Be, B, C, Mn, etc.) and [Co 9 (Te) 6 (CO) 8 ] in O h symmetry, [22][23][24] [Cu 8 (X){E 2 PR 2 } 6 ] n+ [X ) Cl, Br (n ) 1) and S, Se (n ) 0); E ) S, Se] [15][16][17][18][19][20][21] in T h symmetry, and M@Pb 12…”

Section: Introductionmentioning

confidence: 99%

Octanuclear Copper(I) Clusters Inscribed in a Se₁₂Icosahedron: Anion-Induced Modulation of the Core Size and Symmetry

et al. 2009

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Synthesis and structural characterization of an octanuclear Cu(I) cluster [Cu(8){Se(2)P(O(i)Pr)(2)}(6)](PF(6))(2) (1) with an empty Cu(8) cubic core involving diisopropyl diselenophosphate (dsep) ligand has been demonstrated despite its high tendency to abstract anions even from the traces of impurities in the solvent. Reaction of 1 with anion sources (Bu(4)NF for F(-); NaBH(4) for H(-), and NaSH for S(2-)) in a 1:1 ratio produced anion-centered Cu(8) clusters with a formula [Cu(8)(X){Se(2)P(O(i)Pr)(2)}(6)](PF(6)) (X = F, 2a; H, 3a; D, 3a') and [Cu(8)(S){Se(2)P(O(i)Pr)(2)}(6)] (4) in high yields. In addition, fluoride- and hydride-centered Cu(8)(I) clusters [Cu(8)(X){Se(2)P(OEt)(2)}(6)](PF(6)) (X = F, 2b; H, 3b) could be generated in approximately 80% yield by direct reaction of [Cu(CH(3)CN)(4)](PF(6)), NH(4)Se(2)P(OEt)(2), and the anion sources (Bu(4)NF for F(-); NaBH(4) for H(-)) in 8:6:1 ratio. Whereas the structural elucidation of complexes 2 and 4 revealed an anion-centered cubic Cu(8) core surrounded by six dsep ligands, it was a tetracapped tetrahedral copper framework with a hydride in the center in compounds 3. All Cu...Cu distances along either the edge of the cube in 2 and 4 or the tetracapped tetrahedron in 3 are shorter than those identified in 1. Although the cubic (or spherical) contraction of the copper framework that was identified in a series of closed-shell anion-centered (except a hydride) Cu(8) cube having T(h) symmetry could be explained by the existence of strong anion-cation attractions, it was definitely a surprise that the hydride, which is the smallest closed-shell anion and spherical too, induced a tetrahedral contraction of four out of the eight Cu atoms in the empty cube 1, resulting in a tetracapped-tetrahedral geometry and reducing the symmetry to T from T(h). Furthermore the fact that the encapsulated anion induced modulation of the copper core size and symmetry was fully reproduced by DFT calculations on model compounds. To the best of our knowledge, this demonstrated the first example of the reduction of molecular symmetry (from T(h) to T) simply by changing the encapsulated species without altering the general bonding pattern of the surrounding ligands. We also demonstrated that the hydride can easily replace other anions (Cl(-), Br(-), F(-), S(2-), Se(2-)) in a very facile manner to produce hydride-centered species. Eventually, compounds 3 were stable in the presence of other anions, and hydride/deuteride exchange could not be achieved.

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“…3 He proposed that such clusters should then be characterized by 12 n s + i valence electrons with i the characteristic electron count of the interstitial group of n i atoms (18 for one metal, 34 for a dimer, 48 for a triangle, 86 for an octahedron for instance). Given the complexity of such clusters, the agreement between the observed and calculated electron counts was remarkably good even for the highest nuclearity cluster, which was the 44-metal-atom [Ni 38 Pt 6 (CO) 48 H n ] n− (see the Ni 38 Pt 6 core in 34) at that time. 51 The observation that such large clusters conform to this simple electron counting suggested for a while that such species were attaining stable closedshell electronic configurations and therefore were molecules (with substantial HOMO -LUMO gaps) rather than metals in miniature (no HOMO -LUMO gap).…”

Section: Computational Methods: Transition Metal Clusters 13mentioning

confidence: 79%

“…Most can be considered as close-packed (either body centered cubic, bcc, hexagonal, [Ni 38 Pt 6 (CO) 48 H n ] n- (34) hcp, cubic, ccp, or icosahedral, icp) metal cores with ligands bound to surface metal atoms. In the mid-1980s, Mingos tentatively showed that the bonding in such clusters was dependent primarily on peculiar interactions between the surface n s and interstitial n i atoms.…”

Section: Computational Methods: Transition Metal Clusters 13mentioning

confidence: 99%

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Computational Methods: Transition Metal Clusters

Gautier¹,

Halet²,

Saillard³

2005

Encyclopedia of Inorganic Chemistry

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Cluster chemistry is dominated by structural aspects. Indeed, structure and bonding are strongly related to stability and properties, and cluster structures are particularly diverse and often complex. Thus, electron‐counting rules, which relate structure to electron count, have been the key to the development of cluster chemistry as a distinct area of chemistry. These rules have been set up progressively along time with the help of quantum chemistry. This article deals with the recent progress on transition metal and mixed main group/transition metal cluster chemistry arising from the contribution of modern computational theory to the rationalization of structures. This article focuses on “viable” species, i.e., molecules that are isolable under reasonable conditions and deals with the exploration of the limitations of the classical electron‐counting rules as well as the establishment of new rules for new structural types with the help of quantum chemical calculations.

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Electron‐Sponge Behavior, Reactivity and Electronic Structures of Cobalt‐Centered Cubic Co₉Te₆(CO)₈ Clusters

Cited by 20 publications

References 40 publications

In Operando X-ray Absorption Fine Structure Studies of Polyoxometalate Molecular Cluster Batteries: Polyoxometalates as Electron Sponges

In Operando X-ray Absorption Fine Structure Studies of Polyoxometalate Molecular Cluster Batteries: Polyoxometalates as Electron Sponges

Octanuclear Copper(I) Clusters Inscribed in a Se₁₂Icosahedron: Anion-Induced Modulation of the Core Size and Symmetry

Computational Methods: Transition Metal Clusters

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Electron‐Sponge Behavior, Reactivity and Electronic Structures of Cobalt‐Centered Cubic Co9Te6(CO)8 Clusters

Cited by 20 publications

References 40 publications

In Operando X-ray Absorption Fine Structure Studies of Polyoxometalate Molecular Cluster Batteries: Polyoxometalates as Electron Sponges

In Operando X-ray Absorption Fine Structure Studies of Polyoxometalate Molecular Cluster Batteries: Polyoxometalates as Electron Sponges

Octanuclear Copper(I) Clusters Inscribed in a Se12Icosahedron: Anion-Induced Modulation of the Core Size and Symmetry

Computational Methods: Transition Metal Clusters

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Electron‐Sponge Behavior, Reactivity and Electronic Structures of Cobalt‐Centered Cubic Co₉Te₆(CO)₈ Clusters

Octanuclear Copper(I) Clusters Inscribed in a Se₁₂Icosahedron: Anion-Induced Modulation of the Core Size and Symmetry