Mixed Valency in Ligand‐Bridged Diruthenium Complexes

Dey, Sanchaita; Bera, Sudip Kumar; Kaim, Wolfgang; Lahiri, Goutam Kumar

doi:10.1002/9783527835287.ch4

Cited by 2 publications

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References 96 publications

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“…The interactions occur between two or more redox-active metal centers linked by a bridging ligand in chemically identical environments, a phenomenon well-studied in various metal coordination compounds . A notable example is the pyrazine (pz)-bridged dinuclear metal compound, exemplified by the Creutz–Taube ion, where the magnitude of the electronic interactions between two metal redox centers is studied through the stability of the mixed valence state by changes in the bridging ligand. − , The extent of the electronic interaction is usually influenced by the distance between the metal centers, the structure and conformation of the bridging ligand, and the coordination environment of the metal ion . When one metal center is oxidized, the change in the electron density of the compound is transferred to the other metal ion via the bridging ligand, resulting in a higher oxidation potential for the second metal ion .…”

Section: Introductionmentioning

confidence: 99%

Octahedral Hexanuclear Rhenium Cluster Dimers Bridged by Pyrazine or 4,4′-Bipyridine with 23- and 24-Electron Configurations

Yoshimura,

Nagata,

Nakano

2024

Inorg. Chem.

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New pyrazine (pz)-and 4,4′-bipyridine (4,4′-bpy)bridged octahedral hexanuclear rhenium(III) cluster dimers, [{Re 6 (μ 3 -S) 8 Cl 5 } 2 (μ-L)] 6− (L = pz, [1] 6− ; L = 4,4′-bpy, [2] 6− ), with 2 × 24 d-electrons {Re 6 (24e)} 2 were obtained in a single-step reaction via photoirradiation of [Re 6 (μ 3 -S) 8 Cl 6 ] 4− with L in a 2:1 ratio at room temperature. The {Re 6 (23e)} 2 dimers, [{Re 6 (μ 3 -S) 8 Cl 5 } 2 (μ-L)] 4− (L = pz, [1′] 4− ; L = 4,4′-bpy, [2′] 4− ), were synthesized through two-electron oxidation of [1] 6− and [2] 6− , respectively. The single-crystal X-ray structures of [1] 6− and [1′] 4− were determined, revealing structural distortion of the Re 6 core of [1′] 4− due to the Jahn−Teller effect. The cyclic voltammograms of [1] 6− and [2] 6− showed two steps of one-electron redox processes attributable to Re 6 (23e)Re 6 (24e)/{Re 6 (24e)} 2 and {Re 6 (23e)} 2 / Re 6 (23e)Re 6 (24e), respectively. The separation between the two redox potentials is small (0.056 V for [1] 6− and 0.039 V for [2] 6− ). The magnetic susceptibilities of [1′] 4− and [2′] 4− were almost temperature-independent, with values of 2.98 and 2.85 μ B , respectively, indicating paramagnetism. These results suggest weak electronic interaction between two cluster units bridged by pz or 4,4′-bpy in the intercluster mixed valence state. The compounds [1] 6− and [2] 6− show photoluminescence in the near-infrared region at 296 K in the solid state.

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Section: Introductionmentioning

confidence: 99%

Octahedral Hexanuclear Rhenium Cluster Dimers Bridged by Pyrazine or 4,4′-Bipyridine with 23- and 24-Electron Configurations

Yoshimura,

Nagata,

Nakano

2024

Inorg. Chem.

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Diverse Coordination Modes and Bidirectional Noninnocence of Pyridyl-β-diketonate on Ruthenium Platforms as a Function of Coligands

Biswas,

Mobin,

Dey

et al. 2024

Inorg. Chem.

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The article demonstrated diverse binding modes of deprotonated 1,3-di(2-pyridinyl)-1,3-propanedione (HL) (κ2-[O,O]−, κ2-[N,O]−, and μ-bis-κ2-[N,O]−) on selective ruthenium platforms: Ru(acac)2 (dimeric [1]ClO4), Ru(bpy)2 (monomeric [2]ClO4), Ru(pap)2 (isomeric monomeric [3]ClO4/[4]ClO4, dimeric [5](ClO4)3), and Ru(PPh3)2(CO) (monomeric 6, isomeric dimeric [7]ClO4/[8]ClO4) (acac = acetylacetonate, bpy = 2,2′-bipyridine, pap = 2-phenylazopyridine). Structural authentication of the complexes revealed (i) diverse binding mode of L– including its unprecedented bridging mode in [8]ClO4, (ii) varying degrees of nonplanarity of L–, and (iii) development of 1D polymeric chains or dimeric/tetrameric forms via intermolecular π–π interactions. The preferential binding feature of L– in the complexes could also be corroborated by their calculated relative energies. The analysis of the multiredox steps of the complexes suggested severe mixing of metal–ligand frontier orbitals, which in effect pinpointed the involvement of L– in both the oxidative and reductive processes along the redox chain, suggesting its bidirectional noninnocence under the present coordination situations. Though α-diketone or β-diketiminate was reported to activate O2 on the selective Ru(acac)2 platform, the inability of analogous β-diketonate-derived [1]ClO4 could be attributed to its calculated greater HOMO–LUMO energy gap, which disfavored electron exchange at the metal(RuIII)–ligand(L – ) interface to introduce the required unpaired spin at the ligand backbone toward the 3O2 activation event.

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Mixed Valency in Ligand‐Bridged Diruthenium Complexes

Cited by 2 publications

References 96 publications

Octahedral Hexanuclear Rhenium Cluster Dimers Bridged by Pyrazine or 4,4′-Bipyridine with 23- and 24-Electron Configurations

Octahedral Hexanuclear Rhenium Cluster Dimers Bridged by Pyrazine or 4,4′-Bipyridine with 23- and 24-Electron Configurations

Diverse Coordination Modes and Bidirectional Noninnocence of Pyridyl-β-diketonate on Ruthenium Platforms as a Function of Coligands

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