Haloacylation of the Quintuple‐Bonded Group VI Metal Amidinate Dimers and Disproportionation of Acyl Groups to Form Carbynes

Chen, Han-Gung; Hsueh, Hsiang‐Wen; Kuo, Ting‐Shen; Tsai, Yi‐Chou

doi:10.1002/anie.201304750

Cited by 33 publications

(15 citation statements)

References 34 publications

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“…[31] Recently, a series of quintuply bonded dinuclear complexes, M 2 (N^N) 2 {M = Cr, Mo, W, N^N = μ-κ 2 -CH[N(2,6-iPr 2 C 6 H 3 )] 2 }, were synthesized by Tsai et al [32,33] and their aromaticities were determined. [34] Moreover, they have also been shown to exhibit novel reactions with small molecules, such as H 2, [35] RCO-X [36] (X = Cl or Br) and alkynes. [37] On the basis of these results, we were interested in the applicability of Mo 2 (N^N) 2 as a catalyst for radical addition of CCl 4 to 1-hexene.…”

Section: Introductionmentioning

confidence: 99%

Reaction Mechanism and Kinetics study on Addition of CCl₄ to 1‐hexene Catalyzed by Mo‐Mo Quintuply‐bond

Kang

Huo

Meng

et al. 2020

Applied Organom Chemis

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Transition metal-catalyzed atom transfer radical addition (ATRA) reactions are an effective and versatile strategy for constructing carbon-carbon bonds in organic synthesis. Typically, the metal center in this metal-assisted radical transformation undergoes a reversible redox process. In this work, a quintuply-bonded dinuclear complex, Mo 2 (N^N) 2 {N^N = μ-κ 2-CH[N(2,6-iPr 2 C 6 H 3)] 2 }, has been investigated as potential catalyst for radical addition of CCl 4 to 1-hexene by performing density functional theory (DFT) calculations. The study shows that the Mo 2 (N^N) 2-mediated radical addition reaction is computationally predicted to occur with acceptable activation energies, indicating that the Mo-Mo quintuple bond can be applied as an effective catalyst for this transformation under mild conditions. The whole reaction involves 3 steps, two of which are metal-mediated. Firstly, the C-Cl bond activiation catalyzed by Mo 2 (N^N) 2 to obtain Mo 2 (N^N) 2 Cl and •CCl 3 radical; Then the •CCl 3 radical interacts with 1-hexene to get an addition, the addition product reacts with the Mo 2 (N^N) 2 Cl to get the last product and regenerate the catalyst Mo 2 (N^N) 2. Both the thermodynamic and kinetic study show that the second step is the rate-determine step. When coordinating solvent pyridine is added to the catalytic reaction, the reaction is suppressed due to their high energies barriers, which is consistent with experimental results.

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Section: Introductionmentioning

confidence: 99%

Reaction Mechanism and Kinetics study on Addition of CCl₄ to 1‐hexene Catalyzed by Mo‐Mo Quintuply‐bond

Kang

Huo

Meng

et al. 2020

Applied Organom Chemis

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“…7 The reactivities of these quintuply bonded species are currently being explored, and initial studies show promise as inorganic counterparts to the wider reactivity of unsaturated carbon–carbon bonds. 7,8 …”

Section: Introductionmentioning

confidence: 99%

Pushing the Limits of Delta Bonding in Metal–Chromium Complexes with Redox Changes and Metal Swapping

Eisenhart¹,

Rudd²,

Planas³

et al. 2015

Inorg. Chem.

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Into the metalloligand Cr[N(o-(NCH2P(iPr)2)-C6H4)3] (1, CrL) was inserted a second chromium atom to generate the dichromium complex Cr2L (2), which is a homobimetallic analogue of the known MCrL complexes, where M is manganese (3) or iron (4). The cationic and anionic counterparts, [MCrL]+ and [MCrL]−, respectively, were targeted, and each MCr pair was isolated in at least one other redox state. The solid-state structures of the [MCrL]+,0,− redox members are essentially the same, with ultrashort metal–metal bonds between 1.96 and 1.74 Å. The formal shortness ratios (r) of these interactions are between 0.84 and 0.74 and are interpreted as triple to quintuple metal–metal bonds with the aid of theory. The trio of (d–d)10 species [Cr2L]− (2red), MnCrL (3), and [FeCrL]+ (4ox) are S = 0 diamagnets. On the basis of M—Cr bond distances and theoretical calculations, the strength of the metal–metal bond across the (d–d)10 series increases in the order Fe < Mn < Cr. The methylene protons in the ligand are shifted downfield in the 1H NMR spectra, and the diamagnetic anisotropy of the metal–metal bond was calculated as −3500 × 10−36, −3900 × 10−36, and −5800 × 10−36 m3 molecule−1 for 2red, 3, and 4ox respectively. The magnitude of diamagnetic anisotropy is, thus, affected more by bond polarity than by bond order. A comparative vis–NIR study of quintuply bonded 2red and 3 revealed a large red shift in the δ4 → δ3δ* transition energy upon swapping from the (Cr2)2+ to the (MnCr)3+ core. Complex 2red was further investigated by resonance Raman spectroscopy, and a band at 434 cm−1 was assigned as the Cr—Cr bond vibration. Finally, 4ox exhibited a Mössbauer doublet with an isomer shift of 0.18 mm/s that suggests a primarily Fe-based oxidation to Fe(I).

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“…X‐ray crystallographic analysis on 12a and 12b revealed the temperature‐dependent molecular motion. In light of the remarkable reactivity of the type II quintuple‐bonded compounds, the characterization of 5 – 11 bodes well for a systematic reactivity study of these medium‐coordinate univalent dichromium complexes.…”

Section: Discussionmentioning

confidence: 92%

Chromium to chromium quintuple bonds in a trigonal lantern configuration

Yen

Lin

Hsueh

et al. 2019

J Chinese Chemical Soc

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A new family of the quintuply bonded dichromium complexes [Cr2{μ‐κ2‐HC(N‐2,6‐R2C6H3)2}2(μ‐κ2‐HC[NAr]2)] (R = iPr, Ar = 4‐MeC6H4 (5), Ar = 3,5‐Me2C6H3 (6), and Ar = 2,6‐Me2C6H3 (7); R = Et, Ar = 4‐MeC6H4 (8), Ar = 3,5‐Me2C6H3 [9], and Ar = 2,6‐Et2C6H3 (10)) with a heteroleptic lantern configuration was obtained upon the addition of one equivalent of amidinate to the quintuply bonded dichromium amidinates [Cr{μ‐κ2‐HC(N‐2,6‐R2C6H3)2}]2 (R = iPr, Et). Additionally, the same approach was applied to the preparation of the acetate derivative [Cr2{μ‐κ2‐HC(N‐2,6‐ iPr2C6H3)2}2(μ‐κ2‐CH3CO2)] (11), which represents the first example that the quintuply bonded dinuclear complex contains an oxygen‐containing ligand. Of particular interest is that the Cr‐Cr bond lengths in these new trigonal paddlewheel quintuple Cr‐Cr bond species are comparable with those in their precursor compounds. They show ultrashort Cr‐Cr bond lengths in a narrow range of 1.740–1.755 å on the basis of single‐crystal X‐ray crystallography. The small Mayer bond orders of the long Cr‐N bonds as well as divergent, C2v and D3h, structural conformations in 5–11 suggest that the metal–ligand interactions possess minor covalent character and the electrostatic interactions play a dominant role. As a result, these extremely short Cr‐Cr quintuple bonds are caused by the overlap between five pairs of d orbitals that do not involve much in metal–ligand bonding. Additionally, anionic lantern dichromium trisamidinates 5–10 can be chemically oxidized by one electron, supported by electrochemistry, and their ease to undergo oxidation is presumably associated with their neutral lantern dichromium trisamindinate products, whose structures inherently display a Jahn‐Teller distortion, exemplified by the structure of the homoleptic dichromium complex [Cr2{μ‐κ2‐HC(N‐2,6‐Et2C6H3)2}3] [12] determined by X‐ray crystallography. These results unambiguously support the Cr‐Cr quintuple bonding in these novel anionic lantern dichromium complexes.

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Haloacylation of the Quintuple‐Bonded Group VI Metal Amidinate Dimers and Disproportionation of Acyl Groups to Form Carbynes

Cited by 33 publications

References 34 publications

Reaction Mechanism and Kinetics study on Addition of CCl₄ to 1‐hexene Catalyzed by Mo‐Mo Quintuply‐bond

Reaction Mechanism and Kinetics study on Addition of CCl₄ to 1‐hexene Catalyzed by Mo‐Mo Quintuply‐bond

Pushing the Limits of Delta Bonding in Metal–Chromium Complexes with Redox Changes and Metal Swapping

Chromium to chromium quintuple bonds in a trigonal lantern configuration

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Haloacylation of the Quintuple‐Bonded Group VI Metal Amidinate Dimers and Disproportionation of Acyl Groups to Form Carbynes

Cited by 33 publications

References 34 publications

Reaction Mechanism and Kinetics study on Addition of CCl4 to 1‐hexene Catalyzed by Mo‐Mo Quintuply‐bond

Reaction Mechanism and Kinetics study on Addition of CCl4 to 1‐hexene Catalyzed by Mo‐Mo Quintuply‐bond

Pushing the Limits of Delta Bonding in Metal–Chromium Complexes with Redox Changes and Metal Swapping

Chromium to chromium quintuple bonds in a trigonal lantern configuration

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Reaction Mechanism and Kinetics study on Addition of CCl₄ to 1‐hexene Catalyzed by Mo‐Mo Quintuply‐bond

Reaction Mechanism and Kinetics study on Addition of CCl₄ to 1‐hexene Catalyzed by Mo‐Mo Quintuply‐bond