Activation of the B−F Bond by Diphenylcarbene: A Reversible 1,2‐Fluorine Migration between Boron and Carbon

Costa, Paolo; Mieres‐Perez, Joel; Özkan, Nesli; Sander, Wolfram

doi:10.1002/ange.201610179

Cited by 4 publications

(2 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A similar B-F-B bridge with a vibration at 537 cm -1 was recently reported for the complex between tetrachlorocyclopentadienylidene 11 and two molecules of BF3. 38 EPR experiments. The EPR spectrum of T-1b was recorded in argon doped with 1% of BF3 at 5 K, under similar conditions as in the IR experiments.…”

Section: Resultsmentioning

confidence: 99%

Switching the Spin State of Pentafluorophenylnitrene: Isolation of a Singlet Arylnitrene Complex

et al. 2018

Self Cite

View full text Add to dashboard Cite

The chemistry of arylnitrenes is dominated by their triplet ground states and excited open-shell singlet states. This results in radical-type reactions and unwanted rearrangements which diminish the use of arylnitrenes as intermediates in organic synthesis. While the closed-shell singlet states of arylnitrenes are expected to undergo useful chemical transformations (comparable to the closed shell singlet states of carbenes), these states are too high in energy to be chemically accessible. When triplet pentafluorophenylnitrene is interacting with the Lewis acid BF3 under the conditions of matrix isolation, a Lewis acid-base complex consisting of the closed-shell singlet state of the nitrene and two molecules of BF3 is formed. Although the closed shell singlet state of pentafluorophenylnitrene is calculated (CCSD(T)) to lie more than 25 kcal/mol above its triplet ground state, the reaction with BF3 results in switching the spin state from triplet to singlet. The formation of the singlet complex was monitored by IR, UV-vis, and EPR spectroscopy. DFT, CCSD(T), and CASPT2 calculations confirm the experimental findings.

show abstract

Section: Resultsmentioning

confidence: 99%

Switching the Spin State of Pentafluorophenylnitrene: Isolation of a Singlet Arylnitrene Complex

et al. 2018

Self Cite

View full text Add to dashboard Cite

show abstract

“…The characterization of NCI has certainly enriched the concept of chemical bonding initially associated, in a seminal work by Linus Pauling [ 6 ], to electron sharing, which is an idea that will be expanded by including, in addition to conventional covalent or ionic bonds, new weak interactions such as the hydrogen bonds [ 7 , 8 ]. Nowadays, there is a long list of NCIs according to the acceptor nature [ 9 ]: the aforementioned hydrogen bonds (H) [ 10 ], dihydrogen bonds (H) [ 11 , 12 ], alkaline-earth bonds (atoms of column 2 of the periodic table) [ 13 , 14 ], triel bonds (column 13) [ 15 , 16 ], tetrel bonds (column 14) [ 17 ], pnictogen bonds (N, P, As) [ 18 , 19 ], chalcogen bonds (O, S, Se, Te) [ 20 ] or halogen bonds (F, Cl, Br, I) [ 21 , 22 ].…”

Section: Introductionmentioning

confidence: 99%

Large Stabilization Effects by Intramolecular Beryllium Bonds in Ortho-Benzene Derivatives

et al. 2021

View full text Add to dashboard Cite

Intramolecular interactions are shown to be key for favoring a given structure in systems with a variety of conformers. In ortho-substituted benzene derivatives including a beryllium moiety, beryllium bonds provide very large stabilizations with respect to non-bound conformers and enthalpy differences above one hundred kJ·mol−1 are found in the most favorable cases, especially if the newly formed rings are five or six-membered heterocycles. These values are in general significantly larger than hydrogen bonds in 1,2-dihidroxybenzene. Conformers stabilized by a beryllium bond exhibit the typical features of this non-covalent interaction, such as the presence of a bond critical point according to the topology of the electron density, positive Laplacian values, significant geometrical distortions and strong interaction energies between the donor and acceptor quantified by using the Natural Bond Orbital approach. An isodesmic reaction scheme is used as a tool to measure the strength of the beryllium bond in these systems in terms of isodesmic energies (analogous to binding energies), interaction energies and deformation energies. This approach shows that a huge amount of energy is spent on deforming the donor–acceptor pairs to form the new rings.

show abstract

Reactions of Arylcarbenes with Lewis Acids

Raut

Costa

Sander

2018

Chemistry A European J

Self Cite

View full text Add to dashboard Cite

The reactions of the three triplet ground state arylcarbenes diphenylcarbene 1, fluorenylidene 2, and dibenzocycloheptadienylidene 3 with the Lewis acids H O, ICF , and BF were studied under the conditions of matrix isolation. H O was selected as typical hydrogen bond donor, ICF as halogen bond donor, and BF as strong Lewis acid. H O forms hydrogen-bonded complexes of the singlet carbenes with 1 and 2, but not with 3. This is rationalized by the larger singlet-triplet gap of 3, which does not allow to stabilize the singlet state below the triplet state by hydrogen bonding. With ICF , both 1 and 3 form halogen-bonded complexes of the singlet states of the carbenes. This indicates that halogen bonding stabilizes singlet carbenes more than hydrogen bonding. Carbene 2 reacts differently from 1 and 3 by forming an iodonium ylide, thus avoiding antiaromatic destabilization of the fluorenyl unit. With BF , all three carbenes form zwitterionic Lewis acid/base complexes.

show abstract

Activation of the B−F Bond by Diphenylcarbene: A Reversible 1,2‐Fluorine Migration between Boron and Carbon

Cited by 4 publications

References 27 publications

Switching the Spin State of Pentafluorophenylnitrene: Isolation of a Singlet Arylnitrene Complex

Switching the Spin State of Pentafluorophenylnitrene: Isolation of a Singlet Arylnitrene Complex

Large Stabilization Effects by Intramolecular Beryllium Bonds in Ortho-Benzene Derivatives

Reactions of Arylcarbenes with Lewis Acids

Contact Info

Product

Resources

About