Perturbation of 1JC,F Coupling in Carbon–Fluorine Bonds on Coordination to Lewis Acids: A Structural, Spectroscopic, and Computational Study

Skeel, Brighton A.; Boreen, Michael A.; Lohrey, Trevor D.; Arnold, John

doi:10.1021/acs.inorgchem.0c02516

Cited by 3 publications

(3 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The coupling constant of 2 F was comparable to its precursor 6 ( 1 J C–F = 173 Hz) but quite small for the C(sp 2 )–F moiety, which usually exhibits over 200 Hz of 1 J C–F coupling. These observations suggest that the C–F bond in 2 F is significantly activated by the interaction with the potassium cation . Although carbenoid is a generally labile species, compounds 2 F and 2 Cl showed a high thermal stability in the presence of THF molecules coordinating to the potassium cation.…”

Section: Resultsmentioning

confidence: 90%

“…These observations suggest that the C−F bond in 2 F is significantly activated by the interaction with the potassium cation. 59 Although carbenoid is a generally labile species, compounds 2 F and 2 Cl showed a high thermal stability in the presence of THF molecules coordinating to the potassium cation. No conversion was observed on 1 H NMR when the obtained crystals of THF-coordinated 2 X were heated in benzene-d 6 or THF-d 8 even at 80 °C for 18 h. In contrast, replacement of the coordinating solvent on the potassium cation of 2 Cl from THF to toluene resulted in lowering the stability; toluene-coordinated 2 Cl completely decomposed in C 6 D 6 solution at 40 °C, presumably via the reactive carbene intermediate to give a complex mixture, which could not be identified.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Synthesis, Characterization, and Trapping of a Cyclic Diborylcarbene, an Electrophilic Carbene

2023

View full text Add to dashboard Cite

A carbene bearing two geminal boryl substituents, called diborylcarbene (DBC), has been predicted to be highly Lewis acidic in sharp contrast to the well-studied persistent carbenes stabilized by π-donating substituents. Studies on DBC have been limited to either the base-trapping or theoretical calculations. Herein, we developed chemical equivalents for DBC, namely, K/X-diborylcarbenoids 2 X (X = F or Cl). Treatment of 2 F with Al(C 6 F 5 ) 3 yielded [AlF(C 6 F 5 ) 3 ] − -stabilized DBC 1-FAl, which showed a significant low-field shift of the carbenoid carbon from 169 ppm (doublet, coupling with 19 F) to 242 ppm (singlet). The loss of halogen was also detected through electrospray ionization time-of-flight mass spectrometry analysis of 2 X only in the presence of Al(C 6 F 5 ) 3 . Generated DBC 1 from 1-FAl or 2 Cl was successfully trapped with excess amounts of trialkylphosphines (PR 3 , R = Me or Et), which afforded the corresponding DBC-PR 3 adducts. In addition, the Lewis acidity of DBC 1 was evaluated both experimentally and theoretically to reveal that 1 is one of the most Lewis acidic species among neutral molecules.

show abstract

Section: Resultsmentioning

confidence: 90%

Section: ■ Results and Discussionmentioning

confidence: 99%

Synthesis, Characterization, and Trapping of a Cyclic Diborylcarbene, an Electrophilic Carbene

2023

View full text Add to dashboard Cite

show abstract

“…Paramagnetism precluded us from using variable-temperature NMR to determine bond rotation barriers for the CF 3 groups or from obtaining relevant coupling constants, as has been done previously. ,, We therefore turned to density functional theory (DFT) calculations to characterize the close Cu···F contacts in 1 and to determine the origin of the unusual seesaw coordination geometry. Geometry optimizations were performed in the gas phase with the B3LYP functional , and 6-31+G(d,p) basis set − as implemented in Gaussian 16, Revision C.01, and showed excellent agreement with the experimental bond distances and angles (Table S2).…”

Section: Analysis Of Cu···f Interactionsmentioning

confidence: 99%

Distorted Copper(II) Complex with Unusually Short CF···Cu Distances

et al. 2021

View full text Add to dashboard Cite

We find a Cu(II)-(L-CF 3 ) 2 complex (L-CF 3 = 2,2,2-trifluoro-N-[2-(pyridin-2-yl)propan-2-yl]acetamide) with a distorted "seesaw" geometry. It has the shortest crystallographic CF•••Cu distances yet reported, to the best of our knowledge (<2.6 Å), for which computational and experimental data indicate a secondary bonding interaction. A comparison with a CCl 3 version and one without ligand backbone gem-dimethyl groups suggests a steric origin for the distorted geometry, resulting from the specific ligand interactions.

show abstract

Lithium fluoroarylsilylamides and their structural features

Mohan,

Al Ayi,

Anandaraj

et al. 2023

Main Group Metal Chemistry

View full text Add to dashboard Cite

In order to probe the role of Li⋯F interactions toward the stabilisation of low-coordinate lithium complexes, the four fluoroarylsilylamides [LiN(SiMe3)(2-C6H4F)] (1-Li), [LiN(SiMe3)(2,6-C6H3F2)] (2-Li), [LiN(SiMe3)(C6F5)] (3-Li), and [LiN(SiMe2H)(2-C6H4F)] (4-Li) have been synthesised in high yields by deprotonation of the parent amines with nBuLi. They have been comprehensively characterised by multinuclear NMR spectroscopy, and complete assignments were achieved with the help of 2D NMR data. The molecular solid-state structures of [(2-Li)2]∞, [3-Li·Et 2 O]2, and [4-Li]8 were determined by single-crystal X-ray diffraction. They feature unusual coordination patterns, notably for the formation of the polymeric [(2-Li)2]∞ and a unique octagonal, crown-like [4-Li]8. In both structures, the role of Li⋯F non-covalent interactions was the key toward the building of the final architecture. It is shown that Li–F and C–F interatomic distances, along with |1 J C,F| coupling constants, can be used as qualitative tools for the evaluation of the presence and relative strength of Li⋯F contacts.

show abstract

Perturbation of ¹J_C,F Coupling in Carbon–Fluorine Bonds on Coordination to Lewis Acids: A Structural, Spectroscopic, and Computational Study

Cited by 3 publications

References 39 publications

Synthesis, Characterization, and Trapping of a Cyclic Diborylcarbene, an Electrophilic Carbene

Synthesis, Characterization, and Trapping of a Cyclic Diborylcarbene, an Electrophilic Carbene

Distorted Copper(II) Complex with Unusually Short CF···Cu Distances

Lithium fluoroarylsilylamides and their structural features

Contact Info

Product

Resources

About