The Organic Chemistry of Metal-coordinated Cyclopentadienyl and Arene Ligands

Watts, William E.

doi:10.1016/b978-008046518-0.00123-9

Cited by 25 publications

(7 citation statements)

References 427 publications

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“…13 In solution, coordinated cyclopentadienyl ligands are usually stable but also known to undergo a number of reactions, including attacks by electrophilic or nucleophilic agents, metallacyclopentadienylations, ring C−H insertions, cycloadditions, couplings, activations of ring C−C bonds, and insertions into the Cp− M bond. 14,15 Occurrence of any of those reactions on surfaces could complicate the chemistry of ALD processes. 12,16 Here we discuss results from a mechanistic study of the chemistry of methylcyclopentadienyl manganese tricarbonyl (MeCpMn(CO) 3 ) on silica surfaces.…”

Section: Introductionmentioning

confidence: 99%

Reaction of Methylcyclopentadienyl Manganese Tricarbonyl on Silicon Oxide Surfaces: Implications for Thin Film Atomic Layer Depositions

et al. 2014

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The thermal chemistry of methylcyclopentadienyl manganese tricarbonyl (MeCpMn(CO) 3 ) on silicon oxide surfaces was characterized by a combination of analytical techniques, including gas chromatography/mass spectrometry (GC−MS), temperature-programmed desorption (TPD), infrared absorption spectroscopy, and Xray photoelectron spectroscopy (XPS). The compound was found to be fairly stable, but to be able to dissociatively chemisorb on the surface via the loss of one or more carbonyl ligands followed by the oxidative addition of a surface silanol group. Further activation leads to the loss of the aromatic ligand, at temperatures above approximately 575 K. This takes place primarily via the addition of a hydrogen atom to the MeCp ligand to form methylcyclopentadiene, which is released to the gas phase, but a small competing channel starts at slightly lower temperatures that yields fulvene, and/or possibly benzene, after molecular rearrangement. The clean nature of the chemistry seen here for the methylcyclopentadienyl Mn complex makes it a good candidate as a precursor in the chemical deposition of metal thin films. However, the high stability and the high temperatures required for its decomposition do introduce some limitations.

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Section: Introductionmentioning

confidence: 99%

Reaction of Methylcyclopentadienyl Manganese Tricarbonyl on Silicon Oxide Surfaces: Implications for Thin Film Atomic Layer Depositions

et al. 2014

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“…We have recently shown that this limitation may be overcome by using electron excitation of the precursor in the gas phase, but this idea needs to be explored further before its implementation. In any case, the conclusions listed here in terms of the surface chemistry of mixed cyclopentadienyl-carbonyl complexes are likely to be general, since they match what is known of their chemistry in liquid phase − and also apply to similar compounds with other metals. ,, …”

Section: Discussionmentioning

confidence: 71%

Kinetics of Adsorption of Methylcyclopentadienyl Manganese Tricarbonyl on Copper Surfaces and Implications for the Atomic Layer Deposition of Thin Solid Films

Bouman

Zaera

2016

J. Phys. Chem. C

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The kinetics of the thermal chemistry of methylcyclopentadienyl manganese tricarbonyl on copper surfaces was followed by infrared absorption spectroscopy analysis of the gas surrounding the substrate. Dissociative adsorption of the MeCpMn(CO)3 precursor was seen at low temperatures, below 400 K, and was determined to occur via the initial loss of a single carbon monoxide ligand. Full decarbonylation was observed starting at a surface temperature of approximately 510 K, and full decomposition of the Mn precursor was seen to be complete by 540 K. All these transitions were determined to occur at temperatures at least 100 K lower than those reported on silicon oxide surfaces. Comparison with reference spectra afforded the identification of the main hydrocarbon product as a mixture of methylcyclopentadiene isomers. Isothermal measurements of MeCpMn(CO)3 partial pressure versus reaction time highlighted a deviation from first-order kinetics, an effect associated with changes in surface reactivity. A self-limiting regime typical of atomic layer deposition processes was identified between 475 and 525 K by the incomplete conversion of the precursor, which displayed similar reaction rate and reached the same asymptotic partial pressure at all temperatures within that temperature bracket. Higher surface temperatures promoted total precursor consumption, at a rate that increased with increasing surface temperature; an apparent activation energy of approximately 40 kJ/mol was estimated in that high-temperature regime. The resulting chemical-vapor deposited multilayers were identified by X-ray photoelectron spectroscopy to consist of MnO.

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“…Under this scenario, the following characteristics are explained: Where the concentration of incoming ligand F is constant (∼10 M), the reaction obeys first-order kinetics, and the half-life of the reaction is dependent on the concentration of O . The rate of the reaction is largely independent of the reduction potential E ° for O over a range of ∼1.3 V. If O was acting as a redox catalyst, with step 5 in Scheme being rate-determining, then the reaction rate should be dependent exponentially on the O / R reduction potential. Presumably, the reason this catalysis works, even with [Co(Cp) 2 ] + , is that its conjugate [R] = Co(Cp) 2 reacts with either acetone or water impurities and is thus removed from the system As the carbonyl changes from aldehyde to ketone to amide, K 3 is expected to decrease as the equilibrium shifts toward the κ 1 isomer.…”

Section: Resultsmentioning

confidence: 99%

“…The rate of the reaction is largely independent of the reduction potential E ° for O over a range of ∼1.3 V. If O was acting as a redox catalyst, with step 5 in Scheme being rate-determining, then the reaction rate should be dependent exponentially on the O / R reduction potential. Presumably, the reason this catalysis works, even with [Co(Cp) 2 ] + , is that its conjugate [R] = Co(Cp) 2 reacts with either acetone or water impurities and is thus removed from the system …”

Section: Resultsmentioning

confidence: 99%

Electron-Transfer Chain Catalysis of η²-Arene, η²-Alkene, and η²-Ketone Exchange on Molybdenum

et al. 2019

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An oxidant-initiated, substitution process for dihapto-coordinated ligands is described for the {MoTp(NO)(DMAP)} system. Complexes of the form MoTp(NO)(DMAP)(η2-alkene), MoTp(NO)(DMAP)(η2-ketone), and MoTp(NO)(DMAP)(η2-arene) (where Tp = hydridotris(pyrazolyl)borate and DMAP = 4-(dimethylamino)pyridine) undergo an alkene-to-ketone exchange that is catalyzed by the addition of <0.1 equiv of a metallocene oxidant (ferrocenium, permethylferrocenium, or cobaltocenium). A similar acceleration was observed in the presence of the H-bond donor hexafluoroisopropanol (HFIP). From experimental observations, a radical chain propagation mechanism is proposed that is dependent on the equilibrium between dihapto-coordinated (C, O-η2) and monocoordinated (κ-O) isomers and the differing redox characteristics of these two isomeric forms. This concept was then applied to the search of sodium-free reduction conditions for the conversion of MoTp(NO)(DMAP)(I) to various molybdenum(0) complexes of unsaturated ligands, including MoTp(NO)(DMAP)(η2-naphthalene) and MoTp(NO)(DMAP)(α-pinene).

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The Organic Chemistry of Metal-coordinated Cyclopentadienyl and Arene Ligands

Cited by 25 publications

References 427 publications

Reaction of Methylcyclopentadienyl Manganese Tricarbonyl on Silicon Oxide Surfaces: Implications for Thin Film Atomic Layer Depositions

Reaction of Methylcyclopentadienyl Manganese Tricarbonyl on Silicon Oxide Surfaces: Implications for Thin Film Atomic Layer Depositions

Kinetics of Adsorption of Methylcyclopentadienyl Manganese Tricarbonyl on Copper Surfaces and Implications for the Atomic Layer Deposition of Thin Solid Films

Electron-Transfer Chain Catalysis of η²-Arene, η²-Alkene, and η²-Ketone Exchange on Molybdenum

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The Organic Chemistry of Metal-coordinated Cyclopentadienyl and Arene Ligands

Cited by 25 publications

References 427 publications

Reaction of Methylcyclopentadienyl Manganese Tricarbonyl on Silicon Oxide Surfaces: Implications for Thin Film Atomic Layer Depositions

Reaction of Methylcyclopentadienyl Manganese Tricarbonyl on Silicon Oxide Surfaces: Implications for Thin Film Atomic Layer Depositions

Kinetics of Adsorption of Methylcyclopentadienyl Manganese Tricarbonyl on Copper Surfaces and Implications for the Atomic Layer Deposition of Thin Solid Films

Electron-Transfer Chain Catalysis of η2-Arene, η2-Alkene, and η2-Ketone Exchange on Molybdenum

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Electron-Transfer Chain Catalysis of η²-Arene, η²-Alkene, and η²-Ketone Exchange on Molybdenum