Homolytic, Heterolytic, Mesolytic ‐ As You Like It: Steering the Cleavage of a HC(sp3)−C(sp3)H Bond in Bis(1H‐2,1‐benzazaborole) Derivatives

Hejda, Martin; Lyčka, Antonı́n; Mikýsek, Tomáš; Jambor, Roman; Růžička, Aleš; Vinklárek, Jaromı́r; Wilfer, Claudia; Hoffmann, Alexander; Herres‐Pawlis, Sonja; Dostál, Libor

doi:10.1002/chem.201602698

Cited by 7 publications

(6 citation statements)

References 73 publications

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“…The isoelectronic neutral Group 15 analogues have been fully characterized quite recently by the reduction of trivalent precursors (Scheme c) . All of these heterocyclic systems obey the rules for aromatic rings that were unambiguously confirmed by theoretical investigations. − By contrast, related structurally characterized potentially aromatic tellurenyl cations are unknown (Scheme d) …”

Section: Introductionmentioning

confidence: 98%

“…They allowed the isolation of various low-valent species or showed an interesting reactivity at the pendant (−CHNR) arm(s), thereby often producing unique heterocycles, which might possess aromatic character (Scheme ). Thus, the first examples of alkali metal salts of 1 H -2,1-benzazaborolyl anions could be prepared by a C–C bond cleavage in parent 3,3′-bis(1 H -2,1-benzazaborole) by alkali metals (Scheme a) . The germylidenide, stannylidenide, and plumbylidenide anions were isolated by reduction of starting halotetrylenes or corresponding ditetrylenes (Scheme b) .…”

Section: Introductionmentioning

confidence: 99%

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The Aromatic 2-Iminomethylphenyltellurenyl Cation. A Lewis Superacid Despite the Intramolecularly Coordinating N-Donor Ligand

et al. 2020

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The reaction of 2-(tBuNCH)C 6 H 4 TeCl with silver salts of weakly coordinating anions, AgX {X = O 3 SCF 3 , SbF 6 , or Al[OC(CF 3 ) 3 ] 4 }, provided the aryltellurenyl salts [2-(tBuNCH)-C 6 H 4 Te](O 3 SCF 3 ) (1), [2-(tBuNCH)C 6 H 4 Te](SbF 6 ) (2), and [2-(tBuNCH)C 6 H 4 Te]{Al[OC(CF 3 ) 3 ] 4 } (3), which comprise loosely associated ion pairs in the solid state. In solution, 1−3 undergo electrolytic dissociation into the tellurenyl cation [2-(tBuNCH)-C 6 H 4 Te] + ([4] + ) and the respective anions X − to various degrees, which was investigated by multinuclear NMR spectroscopy and conductivity measurements. The electronic structure of 1−3 and [4] + at both multiplicities (M = 1 and 3) was studied by DFT calculations using a set of real-space bond indicators. NICS calculations confirm the aromatic character of the central C 3 NTe ring in [4] + (M = 1). FIA calculations suggest that [4] + is a Lewis superacid.

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Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

The Aromatic 2-Iminomethylphenyltellurenyl Cation. A Lewis Superacid Despite the Intramolecularly Coordinating N-Donor Ligand

et al. 2020

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“…This lengthy route is probably the reason why 2‐iminomethylphenyltellurium species ( VI ) are less frequently described in the literature than other intramolecularly coordinated tellurium compounds ( I – V ) that are more readily available. Recently, 2‐iminomethylphenyl‐supported compounds of group 13, group 14, group 15, and the lighter group 16 elements, were prepared by the ortho ‐directed lithiation route, which prompted us to develop similar synthetic protocols also for tellurium species containing 2‐( tert ‐butyliminomethyl)phenyl‐ and 2‐(2′,6′‐diisopropylphenyliminomethyl)phenyltellurium species ( VI , Scheme ). Five archetypal tellurium compounds were prepared and fully characterized by heteronuclear NMR spectroscopy and X‐ray crystallography.…”

Section: Introductionmentioning

confidence: 99%

Intramolecularly Coordinated 2‐Iminomethylphenyltellurium Compounds

et al. 2017

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Procedures for the synthesis of 2-(tBuNCH)-C 6 H 4 Te(S 2 CNEt 2 ) (1a), 2-(2′,6′-iPr 2 C 6 H 3 NCH)C 6 H 4 Te(S 2 CNEt 2 ) (1b), [2-(tBuNCH)C 6 H 4 ] 2 Te (2a), 2-(tBuNCH)C 6 H 4 TeCl (3a), and 2-(tBuNCH)C 6 H 4 TeCl 3 (4a) have been developed. Compounds 1a-4a possess 2-iminomethylphenyl groups that provide intramolecular N donation to the Te atoms, which was investigated by multinuclear NMR spectroscopy and X-ray crystallography. The Te-N bond lengths increase in the order 3a [2.203 (2) Å] < 4a [2.286(1) Å] < 1b [2.337(2) Å] < 1a [2.407(2) Å] < 2a [a] 3435 Scheme 1. Tellurium compounds stabilized by intramolecular N(sp 3 ) donation (top row) and N(sp 2 ) donation (bottom row). Full PaperScheme 2. General route for the synthesis of 2-iminomethylphenyltellurium compounds reported in the literature. analyzed through DFT calculations and real-space bonding indicators (RSBI), which are derived from the computed electron and pair densities. Topological dissection of the electron density (ED) according to the atoms-in-molecules (AIM) space-partitioning scheme [88] provides a bond-path motif that resembles the molecular structure as well as details of atomic properties such as charges and volumes. Analysis of the reduced density gradient, s(r) = [1/2(3π 2 ) 1/3 ]|∇ρ|/ρ 4/3 , according to the recently introduced noncovalent interactions (NCI) index [89] affords noncovalent bonding aspects. Notably, the assignment of different contact types, including steric/repulsive (λ 2 > 0), van der Waals like (λ 2 ≈ 0), and attractive (λ 2 < 0) interactions is facilitated by mapping the product of the ED and the sign of the second eigenvalue of the Hessian [sign(λ 2 )ρ] on the isosurfaces of s(r). Finally, topological dissection of the pair density according to the electron localizability indicator (ELI-D) [90] provides core, bonding, and lone-pair basins, which are especially valuable for the analysis of covalent (including dative) bonds. ELI-D isosurfaces (localization domain representations of the basins) and NCI isosurfaces show a complementary spatial distribution, [91] which suggests spatial separation of covalent and noncovalent bonding aspects, which has been a matter of recent debate. [92] The combination of AIM, NCI, and ELI-D thus allows the monitoring of minute electronic changes in the Te-N interaction, which is dominated by covalent bonding aspects for short Te-N distances and ionic bonding aspects for longer Te-N distances. These calculations extend previous computational studies on intramolecularly coordinated N-donor tellurium compounds by us [93] and others. [94,95] Scheme 3. Synthesis of 1a-4a and 1b.

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“…Like 2b , radical 2a tends to form a Gomberg-type dimer [2a] 2 , which has been characterized by multinuclear NMR (Scheme ). In line with the dissymmetric nature of the dimer, two distinct signals are observed both in 31 P (δ 21.4 and 15.9 ppm) and 11 B (δ 24.1 and −18.6 ppm) NMR. The dimer [2a] 2 has also been characterized by X-ray diffraction .…”

Section: Resultsmentioning

confidence: 50%

B-Centered Reactivity of Persistent P-Stabilized Boryl Radicals

et al. 2017

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A new P-stabilized boryl radical [iPr2P(naph)BMes]• 2a was obtained by reduction of the corresponding phosphino-bromoborane 1a with Na(Hg). The persistent radical 2a has been characterized by EPR, and its structure has been thoroughly studied by DFT. The corresponding Gomberg-type dimer has been analyzed by NMR and XRD, and the Gibbs free energy associated with the dimerization process has been evaluated by VT EPR. The replacement of the Ph substituents at phosphorus for iPr groups has a slight but noticeable impact: it increases the spin density at boron and favors the radical over its Gomberg-type dimer. An original cross-coupling product between 2a and the trityl radical Ph3C• has also been authenticated crystallographically. The P-stabilized boryl radicals 2a,b are readily trapped by TEMPO to give the corresponding B–O adducts 3a,b (naphthyl-bridged phosphine-boranes without P → B interaction). The reaction of 2a,b with Ph3CCl substantiates their ability to participate in halogen transfer reactions.

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Homolytic, Heterolytic, Mesolytic ‐ As You Like It: Steering the Cleavage of a HC(sp³)−C(sp³)H Bond in Bis(1H‐2,1‐benzazaborole) Derivatives

Cited by 7 publications

References 73 publications

The Aromatic 2-Iminomethylphenyltellurenyl Cation. A Lewis Superacid Despite the Intramolecularly Coordinating N-Donor Ligand

The Aromatic 2-Iminomethylphenyltellurenyl Cation. A Lewis Superacid Despite the Intramolecularly Coordinating N-Donor Ligand

Intramolecularly Coordinated 2‐Iminomethylphenyltellurium Compounds

B-Centered Reactivity of Persistent P-Stabilized Boryl Radicals

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