Cp*Ru Alkoxides with σ-Bridging Phenoxo Groups. X-ray Structure of [Cp*Ru(μ-OMe)(μ-OC6H3-2,4-(t-Bu)2)]

Bücken, Karin; Koelle, U.; Pasch, Roland; Ganter, Beate

doi:10.1021/om9601211

Cited by 18 publications

(9 citation statements)

References 10 publications

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“…2.00 Å. This Ru–O bond length is consistent with known crystallographic data for Ru–O bonds in the range 1.94–2.14 Å. − This supports the hypothesis that complex 3 reacts with the SiO 2 and Al 2 O 3 surfaces, making new Ru–O and Si–H and Al–H bonds, respectively. One of the only differences between the EXAFS data for 3 -SiO 2 and 3 -Al 2 O 3 is that the Ru–O coordination number of 3 -Al 2 O 3 is higher than that of 3 -SiO 2 , suggesting that surface grafting occurs to a greater extent on Al 2 O 3 than on SiO 2 .…”

Section: Resultssupporting

confidence: 86%

Probing the Interactions of Immobilized Ruthenium Dihydride Complexes with Metal Oxide Surfaces by MAS NMR: Effects on CO₂ Hydrogenation

Nguyen

Enenkel

et al. 2021

J. Phys. Chem. C

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Homogeneous catalysts immobilized on metal oxides often have different catalytic properties than in homogeneous solution. This can be either activating or deactivating and is often attributed to interactions of catalyst species with the metal oxide surface. However, few studies have ever demonstrated the effect that close associations of active sites with surfaces have on the catalytic activity. In this paper, we immobilize H2Ru(PPh3)2(Ph2P)2N–C3H6–Si(OEt)3 (3) on SiO2, Al2O3, and ZnO and interrogate the relationship to the surface using IR, MAS NMR, 1H–31P HETCOR, and XAS spectroscopies. We found that while there are close contacts between the P atoms of the complex and all three metal oxide surfaces, the Ru–H bond only reacts with oxygen bridges on SiO2 and Al2O3, forming new Ru–O bonds. In contrast, complex 3 stays intact on ZnO. Comparison of the catalytic activities of our immobilized species for CO2 hydrogenation to ethyl formate showed that Lewis acidic metal oxides activate, rather than deactivate, complex 3 in the order Al2O3 > ZnO > SiO2. The Lewis acidic sites on the metal oxide surfaces most likely increase the productivity by increasing the rate of esterification of formate intermediates.

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Section: Resultssupporting

confidence: 86%

Probing the Interactions of Immobilized Ruthenium Dihydride Complexes with Metal Oxide Surfaces by MAS NMR: Effects on CO₂ Hydrogenation

Nguyen

Enenkel

et al. 2021

J. Phys. Chem. C

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“…Closely related rearrangement of the aryloxo ligand was reported previously for the coordinatively unsaturated Cp*Ru II complexes [(Cp*Ru) 2 (l-OAr) 2 ] (Ar = Ph, C 6 H 3 Pr i Me-2,5, C 6 H 3 Bu t 2 -3,4), which are gradually converted into mononuclear complexes [Cp*Ru(g 5 -OAr)] at room temperature. 5 By contrast, the thiolato analogue [(Cp*Ru) 2 (l-SC 6 H 3 Me2-2,6) 2 ] is stable and does not undergo the core rearrangement of this type under similar conditions. 6…”

Section: Reactions Of 2 With a Cp*ru II Complex Forming Heterobimetal...mentioning

confidence: 99%

Preparation of chalcogenolato-bridged dinuclear TpRh–CpRu complexes (Tp= hydrotris(3,5-dimethylpyrazol-1-yl)borate, Cp=η5-pentamethylcyclopentadienyl) and binding of dioxygen to their Ru sites

et al. 2005

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Reactions of [Tp*Rh(coe)(MeCN)](1; Tp*= hydrotris(3,5-dimethylpyrazol-1-yl); coe = cyclooctene) with one equiv of diphenyl dichalcogenides PhEEPh (E = Se, Te) afforded the mononuclear Rh(III) complexes [Tp*Rh(EPh)(2)(MeCN)](2b: E = Se; 2c: E = Te), as reported previously for the formation of [Tp*Rh(SPh)(2)(MeCN)](2a) from the reaction of 1 and PhSSPh. Complexes 2a-2c were treated with the Ru(II) complex [(Cp*Ru)(4)(mu(3)-Cl)(4)](Cp*=eta(5)-C(5)Me(5)) in THF at room temperature, yielding the chalcogenolato-bridged dinuclear complexes [Tp*RhCl(mu-EPh)(2)RuCp*(MeCN)](3). Complex 3a (E = S) in solution was converted slowly into a mixture of 3a and the sterically less encumbered dinuclear complex [Tp*RhCl(SPh)(mu-eta(1)-S-eta(6)-Ph)RuCp*](4a) at room temperature. In 4a, one SPh group binds only to the Rh center as a terminal ligand, while the other SPh group bridges the Rh and Ru atoms by coordinating to the former at the S atom and to the latter with the Ph group in a pi fashion. The Se analogue 3b also underwent a similar transformation under more forcing conditions, e.g. in benzene at reflux, whereas formation of the mu-eta(1)-Te-eta(6)-Ph complex was not observed for the Te analogue 3c even under these forcing conditions. When complexes 3 was dissolved in THF exposed to air, the MeCN ligand bound to Ru was substituted by dioxygen to give the peroxo complexes [Tp*RhCl(mu-EPh)(2)RuCp*(eta(2)-O(2))](5a: E = S; 5b: E = Se; 5c: E = Te). X-Ray analyses have been undertaken to determine the detailed structures for 2c, 3a, 3b, 4a, 5a, 5b, and 5c.

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“…Late transition metal compounds with anionic nitrogen and oxygen ligands are important intermediates in industrial , and biological processes. While many new complexes of this type have been synthesized recently by our group − and others, − the factors controlling the nature of M−N and M−O bonds are still not well understood.…”

Section: Introductionmentioning

confidence: 99%

Monomeric Cyclopentadienylnickel Methoxo and Amido Complexes: Synthesis, Characterization, Reactivity, and Use for Exploring the Relationship between H−X and M−X Bond Energies

et al. 1997

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Reactive monomeric amido and methoxo complexes, Cp*Ni(PEt3)NHTol and Cp*Ni(PEt3)OMe, have been synthesized and fully characterized. The former is the first monomeric 18-electron nickel amide to be synthesized and the latter is the first structurally characterized monomeric nickel methoxide complex. The amido complex Cp*Ni(PEt3)NHTol reacts with various Brønsted acids (HX) to produce complexes of the type Cp*Ni(PEt3)X (X = NHAr, OR, Osilica, SR), and compounds with hydridic hydrogens to give the hydridonickel complex Cp*Ni(PEt3)H. The polarity of Ni−N and Ni−O bonds is also demonstrated by reactions with alkali metal salts and trimethylsilyl chloride, and by the crystallographic and NMR characterization of phenol adducts of Cp*Ni(PEt3)OTol. The phosphine ligands in Cp*Ni(PEt3)X (X = OTol, SAr) compounds exchange with PMe3 through an associative mechanism; the rate increases with the electronegativity of X. The thermodynamics of reactions interconverting Cp*Ni(PEt3)X + HX‘ and Cp*Ni(PEt3)X‘ + HX have been analyzed using solution equilibrium studies and calorimetry. Instead of being 1:1, the correlation between H−X and M−X bond energies shows a marked preference for nickel binding to more electronegative ligands. This preference is not specific to nickel: examples of similar thermodynamic preferences occur throughout transition metal chemistry. These results may be attributable to a large electrostatic component in the bonding between Ni and X. This qualitative E − C model explains the reactivity, thermodynamics, and phosphine exchange rates of this series of nickel complexes, and may be general to many metal−ligand bonds.

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CpRu Alkoxides with σ-Bridging Phenoxo Groups. X-ray Structure of [CpRu(μ-OMe)(μ-OC₆H₃-2,4-(t-Bu)₂)]

Cited by 18 publications

References 10 publications

Probing the Interactions of Immobilized Ruthenium Dihydride Complexes with Metal Oxide Surfaces by MAS NMR: Effects on CO₂ Hydrogenation

Probing the Interactions of Immobilized Ruthenium Dihydride Complexes with Metal Oxide Surfaces by MAS NMR: Effects on CO₂ Hydrogenation

Preparation of chalcogenolato-bridged dinuclear TpRh–CpRu complexes (Tp= hydrotris(3,5-dimethylpyrazol-1-yl)borate, Cp=η5-pentamethylcyclopentadienyl) and binding of dioxygen to their Ru sites

Monomeric Cyclopentadienylnickel Methoxo and Amido Complexes: Synthesis, Characterization, Reactivity, and Use for Exploring the Relationship between H−X and M−X Bond Energies

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Cp*Ru Alkoxides with σ-Bridging Phenoxo Groups. X-ray Structure of [Cp*Ru(μ-OMe)(μ-OC6H3-2,4-(t-Bu)2)]

Cited by 18 publications

References 10 publications

Probing the Interactions of Immobilized Ruthenium Dihydride Complexes with Metal Oxide Surfaces by MAS NMR: Effects on CO2 Hydrogenation

Probing the Interactions of Immobilized Ruthenium Dihydride Complexes with Metal Oxide Surfaces by MAS NMR: Effects on CO2 Hydrogenation

Preparation of chalcogenolato-bridged dinuclear Tp*Rh–Cp*Ru complexes (Tp*= hydrotris(3,5-dimethylpyrazol-1-yl)borate, Cp*=η5-pentamethylcyclopentadienyl) and binding of dioxygen to their Ru sites

Monomeric Cyclopentadienylnickel Methoxo and Amido Complexes: Synthesis, Characterization, Reactivity, and Use for Exploring the Relationship between H−X and M−X Bond Energies

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CpRu Alkoxides with σ-Bridging Phenoxo Groups. X-ray Structure of [CpRu(μ-OMe)(μ-OC₆H₃-2,4-(t-Bu)₂)]

Probing the Interactions of Immobilized Ruthenium Dihydride Complexes with Metal Oxide Surfaces by MAS NMR: Effects on CO₂ Hydrogenation

Probing the Interactions of Immobilized Ruthenium Dihydride Complexes with Metal Oxide Surfaces by MAS NMR: Effects on CO₂ Hydrogenation

Preparation of chalcogenolato-bridged dinuclear TpRh–CpRu complexes (Tp= hydrotris(3,5-dimethylpyrazol-1-yl)borate, Cp=η5-pentamethylcyclopentadienyl) and binding of dioxygen to their Ru sites