Electronic Structure and Multicatalytic Features of Redox-Active Bis(arylimino)acenaphthene (BIAN)-Derived Ruthenium Complexes

Hazari, Arijit Singha; Ray, Ritwika; Hoque, Asmaul; Lahiri, Goutam Kumar

doi:10.1021/acs.inorgchem.6b01280

Cited by 39 publications

(16 citation statements)

References 122 publications

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“…Interestingly, the influence of the redox‐active ligand scaffold resulted in unusual bond lengths for the carbon–nitrogen and the amino–ruthenium bonds, a result consistent with our initial hypothesis. The Ru–N1 and Ru–N2 distances are within the range of values reported for anionic nitrogen‐based ligands (2.03 Å complex II vs. 1.97 Å literature) [32] . Accordingly, we observe elongation of the C−N bonds (1.28 Å literature vs. 1.36 Å complex II ) when compared to imine bond lengths, as well as the shortening of the C−C bond (1.51 Å literature vs. 1.40 Å complex II ) towards a range more typical for an alkene bond.…”

Section: Resultssupporting

confidence: 78%

“…Them ononuclear nature and the vacant coordination site resulted in ah igh air-a nd moisture-sensitive behavior, with the compound decomposing within seconds when exposed to air.I nterestingly,t he influence of the redox-active ligand scaffold resulted in unusual bond lengths for the carbonnitrogen and the amino-ruthenium bonds,aresult consistent with our initial hypothesis.T he Ru-N1 and Ru-N2 distances are within the range of values reported for anionic nitrogenbased ligands (2.03 complex II vs.1 .97 literature). [32] Accordingly,w eo bserve elongation of the CÀNb onds (1.28 literature vs.1 .36 complex II)w hen compared to imine bond lengths,aswell as the shortening of the C À Cbond (1.51 literature vs.1.40 complex II)towards arange more typical for an alkene bond. Thes olid-state structure of complex I and II clearly supports an ambiguous oxidation state at the Ru-center (Supporting Information, Figures S2, S3).…”

Section: Forschungsartikelmentioning

confidence: 95%

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Ruthenium‐Catalyzed Dehydrogenation Through an Intermolecular Hydrogen Atom Transfer Mechanism

et al. 2021

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The direct dehydrogenation of alkanes is among the most efficient ways to access valuable alkene products. Although several catalysts have been designed to promote this transformation, they have unfortunately found limited applications in fine chemical synthesis. Here, we report a conceptually novel strategy for the catalytic, intermolecular dehydrogenation of alkanes using a ruthenium catalyst. The combination of a redox‐active ligand and a sterically hindered aryl radical intermediate has unleashed this novel strategy. Importantly, mechanistic investigations have been performed to provide a conceptual framework for the further development of this new catalytic dehydrogenation system.

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Section: Resultssupporting

confidence: 78%

Section: Forschungsartikelmentioning

confidence: 95%

Ruthenium‐Catalyzed Dehydrogenation Through an Intermolecular Hydrogen Atom Transfer Mechanism

et al. 2021

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“…Single crystals of both the Ru II and Ru III species were obtained and their structures are shown in Figure B and C, respectively. Complex 2 II displays the typical slightly distorted octahedral geometry around the ruthenium, as expected for a low‐spin d 6 Ru II ion . The bpy ligands occupy both the axial and equatorial positions assuming the κ‐N 1 O 1 ‐pdc 2− ligands bound in the equatorial plane, with a dangling carboxylate not bonded to Ru.…”

Section: Resultsmentioning

confidence: 99%

“…The large g anisotropy and the deviation of the average g factor from the free electron value of 2.0023 indicate a significant contribution from the heavy metal with its high spin‐orbit coupling constant to the spin distribution . The Ru III chlorido complex 1 III also shows a characteristic signal of the corresponding unpaired electron, but with a broader signature (Figure S5e) . Both the Ru II and Ru IV derivatives, 2 II and 2 IV , are EPR‐silent as expected for complexes with no unpaired electrons.…”

Section: Resultsmentioning

confidence: 99%

Catalytic Oxidation of Water to Dioxygen by Mononuclear Ru Complexes Bearing a 2,6‐Pyridinedicarboxylato Ligand

et al. 2019

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The synthesis, purification, and isolation of mononuclear Ru complexes containing the tridentate dianionic meridional ligand pyridyl‐2,6‐dicarboxylato (pdc2−) of general formula [RuIII(pdc‐κ3‐N1O2)(bpy)Cl] (1III) and [RuII(pdc‐κ2‐N1O1)(bpy)2] (2II) (bpy is 2,2′‐bipyridine) is reported. These two complexes and their derivatives were thoroughly characterized through spectroscopic (UV/Vis, NMR) and electrochemical (cyclic voltammetry, differential pulse voltammetry, and coulometry) analyses, and three of the complexes were analyzed by single‐crystal X‐ray diffraction techniques. Under a high anodic applied potential, both complexes evolve towards the formation of Ru‐aquo/oxo derivative species, namely, [RuIII(pdc‐κ3‐N1O2)(bpy)(OH2)]+ (1‐O) and [RuIV(O)(pdc‐κ2‐N1O1)(bpy)2] (2‐O). These two complexes are active catalysts for the oxidation of water to dioxygen and their catalytic activity was analyzed through electrochemical techniques. A maximum turnover frequency (TOFmax)=2.4–3.4×103 s−1 was calculated for 2‐O.

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“…They can be classified as photoCORMs, which are sensitive to visible light even when in a solid state. A comparative study of ruthenium complexes, with R-mian and R-bian in the catalytic reactions of the epoxidation of alkenes [38,39] and oxidation of alcohols [38] was carried out in the works of Lahiri.…”

Section: Introductionmentioning

confidence: 99%

Novel Oxidovanadium Complexes with Redox-Active R-Mian and R-Bian Ligands: Synthesis, Structure, Redox and Catalytic Properties

et al. 2021

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A new monoiminoacenaphthenone 3,5-(CF3)2C6H3-mian (complex 2) was synthesized and further exploited, along with the already known monoiminoacenaphthenone dpp-mian, to obtain oxidovanadium(IV) complexes [VOCl2(dpp-mian)(CH3CN)] (3) and [VOCl(3,5-(CF3)2C6H3-bian)(H2O)][VOCl3(3,5-(CF3)2C6H3-bian)]·2.85DME (4) from [VOCl2(CH3CN)2(H2O)] (1) or [VCl3(THF)3]. The structure of all compounds was determined using X-ray structural analysis. The vanadium atom in these structures has an octahedral coordination environment. Complex 4 has an unexpected structure. Firstly, it contains 3,5-(CF3)2C6H3-bian instead of 3,5-(CF3)2C6H3-mian. Secondly, it has a binuclear structure, in contrast to 3, in which two oxovanadium parts are linked to each other through V=O···V interaction. This interaction is non-covalent in origin, according to DFT calculations. In structures 2 and 3, non-covalent π-π staking interactions between acenaphthene moieties of the neighboring molecules (distances are 3.36–3.40 Å) with an estimated energy of 3 kcal/mol were also found. The redox properties of the obtained compounds were studied using cyclic voltammetry in solution. In all cases, the reduction processes initiated by the redox-active nature of the mian or bian ligand were identified. The paramagnetic nature of complexes 3 and 4 has been proven by EPR spectroscopy. Complexes 3 and 4 exhibited high catalytic activity in the oxidation of alkanes and alcohols with peroxides. The yields of products of cyclohexane oxidation were 43% (complex 3) and 27% (complex 4). Based on the data regarding the study of regio- and bond-selectivity, it was concluded that hydroxyl radicals play the most crucial role in the reaction. The initial products in the reactions with alkanes are alkyl hydroperoxides, which are easily reduced to their corresponding alcohols by the action of triphenylphosphine (PPh3). According to the DFT calculations, the difference in the catalytic activity of 3 and 4 is most likely associated with a different mechanism for the generation of ·OH radicals. For complex 4 with electron-withdrawing CF3 substituents at the diimine ligand, an alternative mechanism, different from Fenton’s and involving a redox-active ligand, is assumed.

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Electronic Structure and Multicatalytic Features of Redox-Active Bis(arylimino)acenaphthene (BIAN)-Derived Ruthenium Complexes

Cited by 39 publications

References 122 publications

Ruthenium‐Catalyzed Dehydrogenation Through an Intermolecular Hydrogen Atom Transfer Mechanism

Ruthenium‐Catalyzed Dehydrogenation Through an Intermolecular Hydrogen Atom Transfer Mechanism

Catalytic Oxidation of Water to Dioxygen by Mononuclear Ru Complexes Bearing a 2,6‐Pyridinedicarboxylato Ligand

Novel Oxidovanadium Complexes with Redox-Active R-Mian and R-Bian Ligands: Synthesis, Structure, Redox and Catalytic Properties

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