Sensitivity of the Valence Structure in Diruthenium Complexes As a Function of Terminal and Bridging Ligands
| Autor: | Reyes Jiménez-Aparicio, Shaikh M. Mobin, Abhishek Mandal, Wolfgang Kaim, José L. Priego, Sebastian Plebst, Goutam Kumar Lahiri, Hemlata Agarwala, Ritwika Ray |
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| Rok vydání: | 2014 |
| Předmět: |
Models
Molecular Transition-Metal-Complexes Hydrogen Nuclear-Magnetic-Resonance Mixed-Valency Stereochemistry Hydroxybutyrates chemistry.chemical_element Anthraquinones Active Quinonoid Ligands Uv-Vis-Nir Crystallography X-Ray Ligands Electronic-Structure Redox Ruthenium law.invention Inorganic Chemistry Metal Magnetics 2 2'-Dipyridyl Atomic orbital Oxidation state law Pentanones Electrochemistry Organometallic Compounds Chelation Benzoquinone Diimine Physical and Theoretical Chemistry Electron paramagnetic resonance Valence (chemistry) Dinuclear Ruthenium Complexes Chemistry Electron Spin Resonance Spectroscopy Redox Series Oxidation-State Crystallography visual_art visual_art.visual_art_medium Spectrophotometry Ultraviolet |
| Zdroj: | Inorganic Chemistry. 53:6082-6093 |
| ISSN: | 1520-510X 0020-1669 |
| DOI: | 10.1021/ic500452h |
| Popis: | The compounds [(acac)(2)Ru-III(mu-H2L2-)Ru-III(acac)(2)] (rac, 1, and meso, 1') and [(bpy)(2)Ru-III(mu-H2L center dot-)Ru-III(bpy)(2)](C1O(4))(3) (meso, [2](ClO4)(3)) have been structurally, magnetically, spectroelectrochemically, and computationally characterized (acac(-) = acetylacetonate, bpy = 2,2'-bipyridine, and H4L = 1,4-diamino-9,10-anthraquinone). The N,O;N',O'-coordinated mu-H2Ln- forms two beta-ketiminato-type chelate rings, and 1 or 1' are connected via NH center dot center dot center dot O hydrogen bridges'in the crystals. 1 exhibits a complex magnetic behavior, while [2](ClO4)(3) is a radical species with mixed ligand/metal-based spin. The combination of redox noninnocent bridge (H2L0 -> -> -> -> H2L4-) and {(acac)(2)Ru-II} -> ->{(acac)(2)Ru-IV} or {(bpy)(2)Ru-II} -> {(bpy)(2)Ru-III} in 1/1' or 2 generates alternatives regarding the oxidation state formulations for the accessible redox states (1(n) and 2(n)), which have been assessed by UV-vis-NIR, EPR, and DFT/TD-DFT calculations. The experimental and theoretical studies suggest variable mixing of the frontier orbitals of the metals and the bridge, leading to the following most appropriate oxidation state combinations: [(acac)(2)Ru-III(mu-H2L center dot-)Ru-III(acac)(2)](+) (1(+)) -> [(acac)(2)Ru-III(mu-H2L2-)Ru-III(acac)(2)] (1) -> [(acac)(2)Ru-III mu-H2L center dot 3-)Ru-III(acac)(2)](-)/[(acac)(2)](-) Ru-III(mu-H2L2-)Ru-III(acac)(2)](-) (1(-)) -> [(acac)(2)Ru-III(mu-H2L4-)Ru-III(acac)(2)](2-)/[(acac)(2)Ru-III(mu-H2L2-)Ru-III(acac)(2)](2-) (1(2-)) and {(bpy)(2)Ru-III(mu-H2L2-)Ru-III(bpy)(2)](4+) (2(4+)) -> [(bpy)(2)Ru-III(mu-H2L center dot-)Ru-II(bpy)(2)](3+)/[(bpy)(2)Ru-III(mu-H2L2-)Ru-III(bpy)(2))(3+) (2(3+)) -> [(bpy)(2)Ru-II(mu-H2L2-)Ru-II(bpy)(2)](2+) (2(2+)). The favoring of Ru-III by sigma-donating acac(-) and of Ru-II by the pi-accepting bpy coligands shifts the conceivable valence alternatives accordingly. Similarly, the introduction of the NH donor function in H2Ln as compared to 0 causes a cathodic shift of redox potentials with corresponding consequences for the valence structure. |
| Databáze: | OpenAIRE |
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