Reactions of a Triruthenium Pentahydrido Complex with Imines Leading to the Formation of a Perpendicularly Coordinated Iminoacyl Ligand and the Scission of a C═N Bond on a Triruthenium Plane

Kanda, Hideyuki; Kawashima, Takayuki; Takao, Toshiro; Suzuki, Hiroharu

doi:10.1021/om201230u

Cited by 12 publications

(15 citation statements)

References 84 publications

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“…To our knowledge all binuclear iminoacyl-bridged complexes reported so far invariably display a 3-electron donor μ-C:N coordination mode. However, a related μ 3 -C,N:C,N:C coordination mode has been proposed to be present in a few trinuclear clusters, 18 although not substantiated crystallographically. The unstable compound 2 gives rise to a 31 P NMR resonance at 168.4 ppm, a position comparable to that of its most stable isomer 4 (δ P 161.3 ppm), thus suggesting their close structural relationship.…”

Section: Structural Characterization Of Compounds 2 Andmentioning

confidence: 99%

Insertion, coupling and elimination processes in the reactions of the unsaturated alkyl-bridged complexes [Mo2(η5-C5H5)2(μ-CH2R)(μ-PCy2)(CO)2] (R = H, Ph) with isocyanides and secondary phosphines

et al. 2014

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The methyl-bridged complex [Mo2Cp2(μ-Me)(μ-PCy2)(CO)2] (Cp = η(5)-C5H5) reacted with stoichiometric amounts of CN(t)Bu at 243 K to give the C,O:C,O-bridged acyl complex [Mo2Cp2{μ-C,O:C,O-C(O)Me}(μ-PCy2)(CN(t)Bu)(CO)], which at room temperature slowly rearranges into its iminoacyl-bridged isomer [Mo2Cp2(μ-C,N:C,N-MeCN(t)Bu)(μ-PCy2)(CO)2]. In contrast, the C:O-bridged acyl complex [Mo2Cp2{μ-C:O-C(O)Me}(μ-PCy2)(CN(t)Bu)(CO)] was the major product obtained when the above reaction was carried out at room temperature. Density Functional Theory (DFT) was used to find the most likely structures of all these isomers, of which the iminoacyl complex was the absolute minimum. In contrast to the above reactions, up to three molecules of the ligand added rapidly to the methyl complex when using the aryl isocyanides CNR (R = o-C6H4Me, p-C6H4OMe), triggering the coupling between the methyl ligand and one of the cyclopentadienyl groups to give the corresponding methylcyclopentadiene derivatives [Mo2Cp(η(4)-C5H5Me)(μ-PCy2)(CNR)3(CO)]. Carbonylation of the latter complex (R = o-C6H4Me) induced the displacement of the η(4)-bound ligand, but also gave small yields of the hydride derivative [Mo2Cp(η(5)-C5H4Me)(μ-H)(μ-PCy2){CN(o-C6H4Me)}(CO)3] (Mo-Mo = 3.2467(5) Å), the latter resulting from a C-H cleavage in the methylcyclopentadiene ligand. The reaction of the title complexes with phosphines HPR (R' = Et, Ph) gave two major products: the corresponding aldehyde complexes [Mo2Cp2(μ-PCy2)(μ-PR){η(2)-C(O)HR}(CO)] (Mo-Mo = 2.8288(5) Å when R = CH2Ph and R' = Et) and the dicarbonyl complexes [Mo2Cp2(μ-PCy2)(μ-PR)(CO)2], these following from alternative reductive elimination processes, from hydrogen and either acyl or alkyl ligands, respectively.

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Section: Structural Characterization Of Compounds 2 Andmentioning

confidence: 99%

Insertion, coupling and elimination processes in the reactions of the unsaturated alkyl-bridged complexes [Mo2(η5-C5H5)2(μ-CH2R)(μ-PCy2)(CO)2] (R = H, Ph) with isocyanides and secondary phosphines

et al. 2014

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“…Formation of the μ 3 -η 2 (∥)-imidoyl complex (Cp*Ru) 3 (H) 4 {μ 3 -η 2 (∥)-PhCNMe} was indicated upon reaction of the perpendicularly coordinated μ 3 -η 2 :η 2 (⊥)-imidoyl complex (Cp*Ru)(μ-H) 2 -{μ 3 -η 2 :η 2 (⊥)-PhCNMe} with H 2 , although the μ 3 -η 2 (∥)imidoyl complex was not isolated due to facile dehydrogenation that regenerated the perpendicular form. 30 Herein, we report on the consecutive transformations of a nitrile ligand on a Ru 3 plane into a primary amine and the catalytic properties of the triruthenium complexes {Cp*Ru(μ-H)} 3 (μ 3 -H) 2 (1) and (Cp*Ru) 3 (μ 3 -H)(μ-H) 2 (μ-CO) (12) toward benzonitrile hydrogenation. The reactions are suitable models for the "M−C" and "M−N" routes, respectively, of nitrile hydrogenation on a metal surface.…”

Section: ■ Introductionmentioning

confidence: 99%

Catalytic Hydrogenation of Benzonitrile by Triruthenium Clusters: Consecutive Transformations of Benzonitrile on the Face of a Ru₃ Plane

et al. 2018

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Reactions of the triruthenium clusters {Cp*Ru(μ-H)}3(μ3-H)2 (1) and (Cp*Ru)3(μ3-H)(μ-H)2(μ-CO) (12) (Cp* = η5-C5Me5) with benzonitrile were investigated in relation to the selective hydrogenation of benzonitrile to benzylamine. Benzonitrile undergoes consecutive transformations into μ3-η2:η2(⊥)-nitrile, μ3-η2:η2(⊥)-imidoyl, μ3-η2(∥)-imidoyl, μ3-η2-alkylideneamido, μ3-imido, and μ-amido ligands on the Ru3 plane accompanied by the uptake of dihydrogen. The reactions are analogues of nitrile hydrogenation on a metal surface. The complexes are structural models of chemisorbed species and catalyze the hydrogenation of benzonitrile. Complex 1 catalyzes benzonitrile hydrogenation without additives but exhibits only moderate selectivity toward benzylamine. Although the μ3-benzylimido complex {Cp*Ru(μ-H)}3(μ3-NCH2Ph) (4) was obtained by reaction of 1 with benzonitrile, it was readily transformed into to the μ3-imidoyl complexes (Cp*Ru)3(μ-H)2{μ3-η2:η2(⊥)-PhCNH} (3) and (Cp*Ru)3(H)4{μ3-η2(∥∥)-PhCNH} (4), which are key intermediates in secondary imine formation. Two benzonitrile molecules were incorporated on the Ru3 plane under the reaction conditions, which decreases the selectivity of primary amine formation. In contrast, μ-carbonyl complex 12 suppresses the incorporation of additional benzonitrile ligands and the formation of μ3-imidoyl species due to the presence of CO. These features of 12 bring about significant improvement in the selectivity of benzonitrile hydrogenation and produce benzylamine in 92% yield.

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“…Nevertheless, a vacant site is readily generated at the Ru 3 site via intramolecular reductive C–H bond formation, which affords a μ-methylene isomer. This motion is known for the isostructural [(Cp*Ru) 3 (μ 3 -CH)(μ-H) 2 (μ 3 -NPh)] and other μ 3 -methylidyne complexes . The 1 H NMR spectrum of 3 recorded at −80 °C displayed a C S structure, where the Cp* signals appeared at δ 2.00 and 1.81 ppm with an intensity ratio of 2:1.…”

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confidence: 99%

Formation of a μ₃-Acetylide on a Ru₃ Cluster via Coupling of μ-Methylene with Isocyanide Accompanied by Elimination of Amine: A Model of Hydrogen-Assisted C–C Bond Formation on a Metal Surface

Chikamori

Takao

2019

Organometallics

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A μ3-methylidyne complex of ruthenium, [(Cp*Ru)3(μ3-CH)(μ-H)2(μ3-S)] (3; Cp* = (C5Me5)Ru), was synthesized by the reaction of [{Cp*Ru(μ-H)}3(μ3-H)2] (1) with thioanisole. Complex 3 isomerized to a μ-methylene intermediate via reductive C–H bond formation, which could uptake a two-electron donor, E, to yield [(Cp*Ru)3(μ-CH2)(μ-H)(μ3-S)(μ-E)] (4, E = CO; 5, E = t-BuNC). Although the μ-carbonyl complex 4 did not undergo C–C bond formation, thermolysis of 5 resulted in formation of the μ3-ethynyl complex [(Cp*Ru)3(μ3-CCH)(μ3-S)] (6), along with elimination of t-BuNH2. In the presence of CF3CH2OH, C–C bond formation proceeded at 25 °C and afforded μ3-aminovinylidene complex [(Cp*Ru){μ3-η2-C = C(N t BuH)H}(μ-H)(μ3-S)] (7), which was also transformed to 6 upon heating at 80 °C. Although C–C bond formation does not occur in the CO analogue, formation of 6 via the reaction with t-BuNC can be viewed as a model of H-assisted C–C bond formation for Fischer–Tropsch synthesis.

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Reactions of a Triruthenium Pentahydrido Complex with Imines Leading to the Formation of a Perpendicularly Coordinated Iminoacyl Ligand and the Scission of a C═N Bond on a Triruthenium Plane

Cited by 12 publications

References 84 publications

Insertion, coupling and elimination processes in the reactions of the unsaturated alkyl-bridged complexes [Mo2(η5-C5H5)2(μ-CH2R)(μ-PCy2)(CO)2] (R = H, Ph) with isocyanides and secondary phosphines

Insertion, coupling and elimination processes in the reactions of the unsaturated alkyl-bridged complexes [Mo2(η5-C5H5)2(μ-CH2R)(μ-PCy2)(CO)2] (R = H, Ph) with isocyanides and secondary phosphines

Catalytic Hydrogenation of Benzonitrile by Triruthenium Clusters: Consecutive Transformations of Benzonitrile on the Face of a Ru₃ Plane

Formation of a μ₃-Acetylide on a Ru₃ Cluster via Coupling of μ-Methylene with Isocyanide Accompanied by Elimination of Amine: A Model of Hydrogen-Assisted C–C Bond Formation on a Metal Surface

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Reactions of a Triruthenium Pentahydrido Complex with Imines Leading to the Formation of a Perpendicularly Coordinated Iminoacyl Ligand and the Scission of a C═N Bond on a Triruthenium Plane

Cited by 12 publications

References 84 publications

Insertion, coupling and elimination processes in the reactions of the unsaturated alkyl-bridged complexes [Mo2(η5-C5H5)2(μ-CH2R)(μ-PCy2)(CO)2] (R = H, Ph) with isocyanides and secondary phosphines

Insertion, coupling and elimination processes in the reactions of the unsaturated alkyl-bridged complexes [Mo2(η5-C5H5)2(μ-CH2R)(μ-PCy2)(CO)2] (R = H, Ph) with isocyanides and secondary phosphines

Catalytic Hydrogenation of Benzonitrile by Triruthenium Clusters: Consecutive Transformations of Benzonitrile on the Face of a Ru3 Plane

Formation of a μ3-Acetylide on a Ru3 Cluster via Coupling of μ-Methylene with Isocyanide Accompanied by Elimination of Amine: A Model of Hydrogen-Assisted C–C Bond Formation on a Metal Surface

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Catalytic Hydrogenation of Benzonitrile by Triruthenium Clusters: Consecutive Transformations of Benzonitrile on the Face of a Ru₃ Plane

Formation of a μ₃-Acetylide on a Ru₃ Cluster via Coupling of μ-Methylene with Isocyanide Accompanied by Elimination of Amine: A Model of Hydrogen-Assisted C–C Bond Formation on a Metal Surface