Reactivity of Ruthenium(II) and Copper(I) Complexes that Possess Anionic Heteroatomic Ligands: Synthetic Exploitation of Nucleophilicity and Basicity of Amido, Hydroxo, Alkoxo, and Aryloxo Ligands for the Activation of Substrates that Possess Polar Bonds as well as Nonpolar C–H and H–H Bonds

Gunnoe, T. Brent

doi:10.1002/ejic.200601072

Cited by 65 publications

(8 citation statements)

References 163 publications

(140 reference statements)

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“…Following the formation of a benzene adduct, the lowest energy C–H activation pathway for both complexes was found to involve concerted metalation–deprotonation (CMD) of benzene using an acetate ligand, − with activation barriers of 21.7 kcal/mol for the Rh-OAc complex and 22.9 kcal/mol for the Rh-TFA complex relative to 2-OAc and 2-TFA , respectively. After benzene C–H activation, the coordinated HX is displaced by ethylene to generate ( Fl DAB)Rh(Ph)(η 2 -C 2 H 4 ) ( 4 ).…”

Section: Resultsmentioning

confidence: 99%

Mechanistic Studies of Single-Step Styrene Production Using a Rhodium(I) Catalyst

et al. 2017

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The direct and single-step conversion of benzene, ethylene, and a Cu(II) oxidant to styrene using the Rh(I) catalyst (DAB)Rh(TFA)(η-CH) [DAB = N,N'-bis(pentafluorophenyl)-2,3-dimethyl-1,4-diaza-1,3-butadiene; TFA = trifluoroacetate] has been reported to give quantitative yields (with Cu(II) as the limiting reagent) and selectivity combined with turnover numbers >800. This report details mechanistic studies of this catalytic process using a combined experimental and computational approach. Examining catalysis with the complex (DAB)Rh(OAc)(η-CH) shows that the reaction rate has a dependence on catalyst concentration between first- and half-order that varies with both temperature and ethylene concentration, a first-order dependence on ethylene concentration with saturation at higher concentrations of ethylene, and a zero-order dependence on the concentration of Cu(II) oxidant. The kinetic isotope effect was found to vary linearly with the order in (DAB)Rh(OAc)(η-CH), exhibiting no KIE when [Rh] was in the half-order regime, and a k/k value of 6.7(6) when [Rh] was in the first-order regime. From these combined experimental and computational studies, competing pathways, which involve all monomeric Rh intermediates and a binuclear Rh intermediate in the other case, are proposed.

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Section: Resultsmentioning

confidence: 99%

Mechanistic Studies of Single-Step Styrene Production Using a Rhodium(I) Catalyst

et al. 2017

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“…We have been interested in the chemistry of substituted 1,1′-ferrocene diamides as ancillary ligands for group 3 metals, lanthanides, and uranium. , In some instances, we observed short iron–metal distances and proposed that the ferrocene diamide supporting ligand was instrumental in stabilizing certain bonding motifs. , To differentiate between the influence of the nitrogen substituent and that of the ferrocene diamide core, we chose the parent 1,1′-ferrocene diamine, (fc(NH 2 ) 2 ), as a platform to study metal–metal bonding. Inspired by Seyferth’s and Sato’s pioneering work with late transition metals, and because of numerous reports of stable amine − and amide − ruthenium compounds, we chose to investigate ruthenium complexes. Additionally, the syntheses of the dichloride [fc(NH 2 ) 2 ]RuCl 2 (PPh 3 ) 2 ( 1 ) and of the diamide [fc(NH) 2 ]Ru(PPh 3 ) 2 ( 2 ) species were recently reported by us …”

Section: Resultsmentioning

confidence: 99%

Characterization of an Iron–Ruthenium Interaction in a Ferrocene Diamide Complex

et al. 2013

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Reaction of [fc(NH2)2]RuCl2(PPh3)2 (fc = 1,1'-ferrocenylene) with 2 equiv of KO(t)Bu led to the formation of a diamido ruthenium complex, [fc(NH)2]Ru(PPh3)2, whose solid-state molecular structure revealed a short Fe-Ru distance. A metal-to-metal charge transfer band was observed in the electronic absorption spectrum of [fc(NH)2]Ru(PPh3)2. The Fe-Ru interaction was characterized by resonance Raman spectroscopy for the first time and also by (1)H NMR, UV-vis, NIR, Mössbauer spectroscopy, and X-ray crystallography. Density functional theory (DFT) calculations including natural bond order analysis, Bader's atom in molecules method, and time-dependent DFT (TDDFT) provided further support that the iron-ruthenium bond is a weak donor-acceptor interaction with iron acting as the Lewis base.

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“…Well-defined late transition-metal complexes containing nondative σ metal–heteroatom bonded ligands, such as hydroxo, alkoxo, amido, or fluoro, compose a fascinating class of compounds . While these are commonly found as inert or spectator ligands in complexes with metals from groups 4–6, they become less common and more reactive in those of the second half of the transition series.…”

Section: Introductionmentioning

confidence: 99%

Nickel Pincer Complexes with Frequent Aliphatic Alkoxo Ligands [(^iPrPCP)Ni-OR] (R = Et, nBu, iPr, 2-hydroxyethyl). An Assessment of the Hydrolytic Stability of Nickel and Palladium Alkoxides

et al. 2017

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A series of nickel pincer complexes with terminal alkoxo ligands [(PCP)Ni-OR] (R = Et, nBu, iPr, CHCHOH; PCP is the 2,6-bis(diisopropylphosphinomethyl)phenyl pincer ligand) was synthesized and fully characterized. Together with the previously reported methoxo analogues of Ni and Pd, these complexes constitute a unique series of isostructural late transition-metal alkoxides. Spectroscopic and X-ray diffraction data provide direct indications of the strong polarization of their covalent Ni-OR bonds. One of the most salient features of this class of compounds is their facile hydrolysis with traces of moisture, leading to equilibrium mixtures with the corresponding hydroxides [(PCP)M-OH] (M = Ni or Pd) and alcohols, ROH. To compare the hydrolytic stability of nickel and palladium alkoxides, we performed NMR titrations of both hydroxides with several alcohols and determined the corresponding equilibrium constants. In general, these constants are ca. 1 order of magnitude smaller for M = Ni than Pd, indicating that Ni alkoxide complexes are more readily hydrolyzed than their Pd counterparts. For alkoxide complexes containing heteroatom-free R groups, the tendency to hydrolyze decreases as the parent alcohol ROH becomes more acidic, that is, R = Me > Et > iPr. This intuitive trend is broken for 2-methoxyethanol, the most acidic alcohol investigated. The hydroxo/2-methoxyethanol exchange equilibrium constants are comparable to those of ethanol (M = Ni) or methanol (M = Pd), showing that the corresponding 2-methoxyethoxide complexes are more prone to hydrolysis than anticipated. These experimental observations were rationalized in the light of density functional theory calculations.

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Reactivity of Ruthenium(II) and Copper(I) Complexes that Possess Anionic Heteroatomic Ligands: Synthetic Exploitation of Nucleophilicity and Basicity of Amido, Hydroxo, Alkoxo, and Aryloxo Ligands for the Activation of Substrates that Possess Polar Bonds as well as Nonpolar C–H and H–H Bonds

Cited by 65 publications

References 163 publications

Mechanistic Studies of Single-Step Styrene Production Using a Rhodium(I) Catalyst

Mechanistic Studies of Single-Step Styrene Production Using a Rhodium(I) Catalyst

Characterization of an Iron–Ruthenium Interaction in a Ferrocene Diamide Complex

Nickel Pincer Complexes with Frequent Aliphatic Alkoxo Ligands [(^iPrPCP)Ni-OR] (R = Et, nBu, iPr, 2-hydroxyethyl). An Assessment of the Hydrolytic Stability of Nickel and Palladium Alkoxides

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Reactivity of Ruthenium(II) and Copper(I) Complexes that Possess Anionic Heteroatomic Ligands: Synthetic Exploitation of Nucleophilicity and Basicity of Amido, Hydroxo, Alkoxo, and Aryloxo Ligands for the Activation of Substrates that Possess Polar Bonds as well as Nonpolar C–H and H–H Bonds

Cited by 65 publications

References 163 publications

Mechanistic Studies of Single-Step Styrene Production Using a Rhodium(I) Catalyst

Mechanistic Studies of Single-Step Styrene Production Using a Rhodium(I) Catalyst

Characterization of an Iron–Ruthenium Interaction in a Ferrocene Diamide Complex

Nickel Pincer Complexes with Frequent Aliphatic Alkoxo Ligands [(iPrPCP)Ni-OR] (R = Et, nBu, iPr, 2-hydroxyethyl). An Assessment of the Hydrolytic Stability of Nickel and Palladium Alkoxides

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Nickel Pincer Complexes with Frequent Aliphatic Alkoxo Ligands [(^iPrPCP)Ni-OR] (R = Et, nBu, iPr, 2-hydroxyethyl). An Assessment of the Hydrolytic Stability of Nickel and Palladium Alkoxides