Flexible C−C Bonds: Reversible Expansion, Contraction, Formation, and Scission of Extremely Elongated Single Bonds

Shimajiri, Takuya; Suzuki, Takanori; Ishigaki, Yusuke

doi:10.1002/ange.202010615

Cited by 9 publications

(2 citation statements)

References 48 publications

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“…Notably, the first synthesis of hexaphenylcarbodiphosphorane I was reported as being realized through the reduction of its conjugate acid (methylidebis-(triphenylphosphonium)bromide), using potassium metal in diglyme. [1 a)] Finally, to address the oxidation [60] of 11a/11b, they were studied by cyclic voltammetry in THF/0.1 M [Bu 4 N][PF ] (Figures S106-S112). The voltammograms show oxidation waves at E pa = À 1.17 and À 0.91 V vs. Fc/Fc + , respectively.…”

Section: Chemistry-a European Journalmentioning

confidence: 99%

Carbodicarbenes and Striking Redox Transitions of their Conjugate Acids: Influence of NHC versus CAAC as Donor Substituents

Dolai

Kumar

Elvers

et al. 2022

Chemistry A European J

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Herein, a new type of carbodicarbene (CDC) comprising two different classes of carbenes is reported; NHC and CAAC as donor substituents and compare the molecular structure and coordination to Au(I)Cl to those of NHC‐only and CAAC‐only analogues. The conjugate acids of these three CDCs exhibit notable redox properties. Their reactions with [NO][SbF6] were investigated. The reduction of the conjugate acid of CAAC‐only based CDC with KC8 results in the formation of hydrogen abstracted/eliminated products, which proceed through a neutral radical intermediate, detected by EPR spectroscopy. In contrast, the reduction of conjugate acids of NHC‐only and NHC/CAAC based CDCs led to intermolecular reductive (reversible) carbon–carbon sigma bond formation. The resulting relatively elongated carbon–carbon sigma bonds were found to be readily oxidized. They were, thus, demonstrated to be potent reducing agents, underlining their potential utility as organic electron donors and n‐dopants in organic semiconductor molecules.

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Section: Chemistry-a European Journalmentioning

confidence: 99%

Carbodicarbenes and Striking Redox Transitions of their Conjugate Acids: Influence of NHC versus CAAC as Donor Substituents

Dolai

Kumar

Elvers

et al. 2022

Chemistry A European J

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“…While a typical C-C bond length is 1.54 Å, reports of experimentally synthesized compounds with a bond distance longer than 1.8 Å or even 2.0 Å are available in the literature. [1][2][3][4][5][6] These spectacular accomplishments sparked a cohort of investigators looking into the mechanism of their underlying interactions. 1,[7][8][9] It is commonly believed that weak, van der Waals interactions, especially dispersion forces, are responsible for the formation and stability of these exceedingly long carbon-carbon single bonds.…”

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confidence: 99%

The Synergetic and Multifaceted Nature of Carbon-Carbon Rotation Reveals the Origin of Stability for Bulky Alkane Dimers

Liu

Wan

et al. 2022

Preprint

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Designing compounds with as long carbon-carbon bond distances as possible to challenge conventional chemical wisdom is of current interest in the literature. These compounds with exceedingly long bond lengths are commonly believed to be stabilized by dispersion interactions. In this work, we build nine dimeric models with varying sizes of alkyl groups, let the carbon-carbon bond flexibly rotate, and then analyze rotation barriers with energy decomposition and information-theoretic approaches in density functional theory. Our results show that these rotations lead to extraordinarily elongated carbon-carbon bond distances and rotation barriers are synergetic and multifaceted in nature. The dominant factor contributing to the stability of the dimers with bulky alkane groups is not the dispersion force but the electrostatic interaction with steric and exchange-correlation effects playing minor yet indispensable roles.

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Synthesis of Anthracene‐Based Cyclic π‐Clusters and Elucidation of their Properties Originating from Congested Aromatic Planes

2021

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Synthesis and properties of anthracene-based cyclic p-clusters which possess two and four anthracene units are discussed. The optimal cyclization conditions were determined based on an ickel(0)-mediated reaction that afforded ac yclic anthracene dimer as the major product. Bringing two anthracene planes in close proximity in aface-to-face manner resulted in red-shifted absorption owing to the narrowing of the HOMO-LUMO gap.T he cyclic anthracene dimer exhibits multi-stimuli responsiveness due to high p-congestion. For example,photoirradiation on the anthracene dimer affords its photoisomer having CÀCb onds that are longer than 1.65 , which can undergo thermal reversion under gentle heating. This enabled mechanochromism of the photoisomer (colorless) to the original anthracene dimer (red). Photoisomerization was also observed in the crystalline state,accompanied by crystal jumping or collapsing,t hat is,t he photosalient effect. Figure 1. Anthracene-based cyclic p-clusters 1 and 2.

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Flexible C−C Bonds: Reversible Expansion, Contraction, Formation, and Scission of Extremely Elongated Single Bonds

Cited by 9 publications

References 48 publications

Carbodicarbenes and Striking Redox Transitions of their Conjugate Acids: Influence of NHC versus CAAC as Donor Substituents

Carbodicarbenes and Striking Redox Transitions of their Conjugate Acids: Influence of NHC versus CAAC as Donor Substituents

The Synergetic and Multifaceted Nature of Carbon-Carbon Rotation Reveals the Origin of Stability for Bulky Alkane Dimers

Synthesis of Anthracene‐Based Cyclic π‐Clusters and Elucidation of their Properties Originating from Congested Aromatic Planes

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