Nineteen-electron complexes and their role in organometallic mechanisms

Astruc, Didier

doi:10.1021/cr00089a010

Cited by 201 publications

(93 citation statements)

References 107 publications

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“…5b and monoexponential fits to these kinetic traces yield rise times of 43 ± 7 µs and 45 ± 5 µs for H and I, respectively. We propose that these peaks arise from the ionic products CpW(CO) 2 …”

Section: Insert Fig 4 Approximately Herementioning

confidence: 97%

“…The ultrafast disproportionation mechanism is displayed in Scheme 1. Irradiation of [CpW(CO) 3 ] 2 (A) at visible wavelengths results in metal-metal bond homolysis to form two 17e radicals, CpW(CO) 3 (B). The nascent radicals are surrounded by a cage of solvent molecules, represented by brackets in Scheme 1.…”

Section: Insert Scheme 1 Approximately Herementioning

confidence: 99%

“…The reactivity of organometallic radicals is an important and ongoing question; oddelectron transition-metal species are used as synthetic precursors for more complex organometallic compounds and have also been shown to participate in important catalytic and electron-transfer reactions [1,2]. 17-electron (17e) metal-centered radicals are the most common transition-metal radicals and can be photochemically generated from organometallic dimers containing a single metal-metal bond; irradiation of [CpW(CO) 3 5 ] 2 produces the 17e radicals CpW(CO) 3 , CpFe(CO) 2 , and Mn(CO) 5 , respectively [1].…”

Section: Introductionmentioning

confidence: 99%

“…17-electron (17e) metal-centered radicals are the most common transition-metal radicals and can be photochemically generated from organometallic dimers containing a single metal-metal bond; irradiation of [CpW(CO) 3 5 ] 2 produces the 17e radicals CpW(CO) 3 , CpFe(CO) 2 , and Mn(CO) 5 , respectively [1].…”

Section: Introductionmentioning

confidence: 99%

“…The mechanism of this unique reaction was analyzed and evidence was found for the existence of a highly reactive 19-electron (19e) radical, CpM(CO) 3 PR 3 [6][7][8]. These same dimers were also observed to participate in ligand substitution reactions to produce the products [CpM(CO) 2 [9].…”

Section: Introductionmentioning

confidence: 99%

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DFT and time-resolved IR investigation of electron transfer between photogenerated 17- and 19-electron organometallic radicals

Cahoon¹,

Kling²,

Sawyer³

et al. 2008

Journal of Molecular Structure

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Section: Insert Fig 4 Approximately Herementioning

confidence: 97%

Section: Insert Scheme 1 Approximately Herementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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DFT and time-resolved IR investigation of electron transfer between photogenerated 17- and 19-electron organometallic radicals

Cahoon¹,

Kling²,

Sawyer³

et al. 2008

Journal of Molecular Structure

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Carbonyl Complexes of the Transition Metals

Calderazzo¹

2005

Encyclopedia of Inorganic Chemistry

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Carbon monoxide is a versatile ligand as it forms compounds with both transition metals and main group elements. Transition d metals of electronic configuration d n (0 < n < 10) form the most numerous class of these compounds, although recent progress has been made in expanding the area of existence toward main group, lanthanide (4f) and actinide (5f) metals. The most extensively studied series of carbonyl derivatives have the general formula [M(CO) n ] m , with n representing the coordination number of the central metal atom M, and m being the nuclearity of the system. In these compounds, the central metal atom is in the zero oxidation state. Starting from readily available inorganic derivatives in a positive oxidation state, the synthesis of these compounds normally requires a reducing agent capable of acting in the presence of carbon monoxide: in fact, only nickel metal, as a finely divided activated powder, is reactive toward CO leading to the corresponding derivative Ni(CO) 4 . The selection of the reducing agent varies as a function of the position of the metal M within the periodic table. There is a general trend of an increase in the nuclearity m toward the end of the transition d series, the nuclearity being related to the bonding arrangements of the CO ligand, which may act as terminal, doubly bridging or triply bridging. Metal carbonyls are characterized by IR‐active vibrations around 2000 cm −1 associated with the carbonyl groups. Vibrational spectra in solution give important information about: (a) the electronic distribution within the M–CO bond in terminally bonded carbonyl groups; (b) the molecular structure associated with the number of bands observed; (c) the type of bonding in dinuclear or polynuclear compounds. X‐ray diffraction data have been extensively used in order to define the molecular structure in the solid state. The metal–CO combinations span a wide range of oxidation states, derivatives being known for oxidation states from +III to −IV. Metal carbonyls undergo three types of reaction: (a) substitution of the carbonyl groups, whereby the oxidation state of the central metal atom remains unchanged, (b) oxidation, and (c) reduction. Carbonyl derivatives of early‐ and late transition metals present specific bonding and spectroscopic properties. Concerning the transition elements of groups 6–9, the M–CO bond dissociation enthalpy increases down the group, and is normally greater than the metal–metal bond enthalpy, the latter being estimated from the heat of atomization. From a mechanistic viewpoint, substitution and redox reactions have been studied extensively. A special case of substitution is the migratory carbonyl insertion, by which an M–R bond to a carbyl group R is converted by CO into the M–(CO)R sequence.

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Iron: Organometallic ChemistryBased in part on the article Iron: Organometallic Chemistry by James R. Green which appeared in theEncyclopedia of Inorganic Chemistry, First Edition.

Paley¹

2005

Encyclopedia of Inorganic Chemistry

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Studies involving the preparation, reactivity, and properties of the organometallic complexes of iron (compounds possessing a FeC bond) have played a central role in the growth of organometallics as a major subdiscipline with chemistry. From the discovery of ferrocene in the 1950s to the present day, interest and research activity remain high. This entry provides a survey of this large and diverse area of organometallic chemistry, and is arranged by increasing hapticity of the organic ligand of interest that is bound to iron. Included are discussions of the chemistry of iron σ‐alkyl, acyl, alkynyl, and vinyl complexes, iron carbenes, η1‐ and η3‐allyl iron complexes, η2‐alkene and η4‐diene iron complexes, trimethylenemethane and cyclobutadiene complexes of iron, cationic iron pentadienyl, cyclohexadienyl, and arene complexes, and ferrocenes and heteroferrocenes.

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Nineteen-electron complexes and their role in organometallic mechanisms

Cited by 201 publications

References 107 publications

DFT and time-resolved IR investigation of electron transfer between photogenerated 17- and 19-electron organometallic radicals

DFT and time-resolved IR investigation of electron transfer between photogenerated 17- and 19-electron organometallic radicals

Carbonyl Complexes of the Transition Metals

Iron: Organometallic ChemistryBased in part on the article Iron: Organometallic Chemistry by James R. Green which appeared in theEncyclopedia of Inorganic Chemistry, First Edition.

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