Multiple metal-carbon bonds. 7. Preparation and characterization of Ta(.eta.5-C5H5)2(CH2)(CH3), a study of its decomposition, and some simple reactions

Schrock, Richard R.; Sharp, Paul R.

doi:10.1021/ja00476a022

Cited by 202 publications

(140 citation statements)

References 9 publications

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“…Historically, the first isolable transition metal methylene complex, Cp2Ta(=CH2)Me, was prepared by Schrock by electrophilic abstraction of Me -from Cp2TaMe3 by action of Ph3C + , followed by deprotonation by Me3P(CH2) or other bases. 11,211 Formation of a methylidene terminus by abstraction of either a proton or a hydride is a prevailing transformation. This can occur by four different routes (Scheme 37): (i) intermolecular deprotonation; (ii) intermolecular hydride abstraction; (iii) intramolecular hydrogen abstraction; and (iii) α-hydrogen elimination.…”

Section: Protonolysis and Hydrogenolysismentioning

confidence: 99%

Methyl Complexes of the Transition Metals

Campos

López‐Serrano

Peloso

et al. 2016

Chemistry A European J

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Organometallic chemistry can be considered as a wide area of knowledge that combines concepts of classic organic chemistry, i.e. based essentially on carbon, with molecular inorganic chemistry, especially with coordination compounds. Transition metal methyl complexes probably represent the simplest and most fundamental way to view how these two major areas of chemistry combine and merge into novel species with intriguing features in terms of reactivity, structure, and bonding. Citing more than 500 bibliographic references, this review aims to offer a concise view of recent advances in the field of transition metal complexes containing M-CH3 fragments. Taking into account the impressive amount of data that are continuously provided by organometallic chemists in this area, this review is mainly focused on results of the last 5 years. After a panoramic overview on M-CH3 compounds of groups 3 to 11 which includes the most recent landmark findings in this area, two further sections are dedicated to methyl-bridged complexes and reactivity.

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Section: Protonolysis and Hydrogenolysismentioning

confidence: 99%

Methyl Complexes of the Transition Metals

Campos

López‐Serrano

Peloso

et al. 2016

Chemistry A European J

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“…[194] Compound 54 does not react with ethylene, acetone, or CO 2 , but reacts smoothly with CO to form the enediolate complex. Benzamidinato complexes of tantalum are accessible by analogous routes.…”

Section: Compounds With Metals In the High Oxidation State And The Anmentioning

confidence: 99%

Highlights in the Renaissance of Amidometal Chemistry

Kempe¹

2000

Angewandte Chemie International Edition

271

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Turning a disadvantage to an advantage: The rather disappointing reactivity of the metal - nitrogen bond in comparison to the metal - carbon bond resulted in the neglect of amidometal chemistry after its heyday at the end of the 1960s and beginning of the 1970s. Today it is precisely this disadvantage which is being applied through the use of amido ligands to produce inert complex fragments with well-defined reaction centers. In this way the chemistry of the early transition metals has been markedly enriched, and interesting alternatives to the classically regarded cyclopentadienyl ligands are now available.

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“…In its reduced form, [ONO red ] 3À is a planar, tridentate ligand that coordinates to transition metals in a meridional geometry. The organometallic synthon TaMe 3 Cl 2 [7] has been used to prepare [ONO red ]TaMe 2 (1), which was then converted into the; 2 b, L = pyridine (py); Scheme 1). Oxidation of 2 b resulted in the quantitative elimination of (p-tolyl)N = N(ptolyl).…”

mentioning

confidence: 99%

Four‐Electron Oxidative Formation of Aryl Diazenes Using a Tantalum Redox‐Active Ligand Complex

Zarkesh¹,

Ziller²,

Heyduk³

2008

Angew Chem Int Ed

150

121

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Transition-metal complexes capable of mediating multielectron transformations are critical components for a variety of small-molecule transformations. For example, the oxidation of CÀH bonds [1] and the reduction of protons to H 2 [2] are both two-electron transformations. The oxidation of water to O 2 is a four-electron process [3] and the reduction of nitrogen to ammonia is an overall six-electron process.[4] The design of metal complexes to promote or catalyze these multielectron reactions usually relies on one or more transition-metal ions capable of two-electron changes in a formal oxidation state. An alternative strategy is to incorporate redox-active ligands into the metal coordination sphere to supply reducing or oxidizing equivalents during a multielectron transformation.[5]Herein, we report the use of a tridentate redox-active ligand,, [6] coordinated to tantalum, to effect the fourelectron oxidative formation of aryl diazenes. In its reduced form, [ONO red ] 3À is a planar, tridentate ligand that coordinates to transition metals in a meridional geometry. The organometallic synthon TaMe 3 Cl 2 [7] has been used to prepare [ONO red ]TaMe 2 (1), which was then converted into the; 2 b, L = pyridine (py); Scheme 1). Oxidation of 2 b resulted in the quantitative elimination of (p-tolyl)N = N(ptolyl). To the best of our knowledge, this is the first example of N = N double bond formation and organic diazene elimination from a tantalum(V) bridging imido dimer. Oxidation studies of the related complex [ONO red ]TaCl 2 (4) with PhICl 2 suggest that the redox-active ligand plays the pivotal role of collecting oxidizing equivalents within the tantalum coordination sphere. The work presented herein highlights a new strategy for the design of metal complexes capable of multielectron oxidation reactions.The bridging imido complexes 2 a and 2 b were prepared via dimethyl complex 1 (Scheme 1). The methyl ligands of 1 are susceptible to protonolysis by anilines, which results in the formation of bimetallic complexes with two bridging imido ligands. As shown in Scheme 1, benzene solutions of 1 heated to reflux with two equivalents of NH 2 (p-tolyl) resulted in the formation of

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Multiple metal-carbon bonds. 7. Preparation and characterization of Ta(.eta.5-C5H5)2(CH2)(CH3), a study of its decomposition, and some simple reactions

Cited by 202 publications

References 9 publications

Methyl Complexes of the Transition Metals

Methyl Complexes of the Transition Metals

Highlights in the Renaissance of Amidometal Chemistry

Four‐Electron Oxidative Formation of Aryl Diazenes Using a Tantalum Redox‐Active Ligand Complex

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