Pentafluorophenylcopper Tetramer, A Reagent for Synthesis of Fluorinated Aromatic Compounds

Cairncross, Allan; Sheppard, William A.; Wonchoba, E. R.

doi:10.1002/0471264180.os059.18

Cited by 29 publications

(40 citation statements)

References 15 publications

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“…However,t he synthesis of BTolF via ad onor-free copper(I)-based transfer was successful. This method is related to avariant of the BCF synthesis via C 6 F 5 Cu [17] by Jäkle et al [18] Thep recursor p-bromoheptafluorotoluene (2)w as obtained in 64 %y ield after distillation by bromination of neat perfluorotoluene (1)w ith aluminum tribromide at 130 8 8C along am odified procedure [19] (Scheme 1). [19] Thec orresponding Grignard reagent was prepared and treated with copper(I) bromide.A ddition of 1,4-dioxane precipitated the magnesium salts allowing them to be separated by filtration.…”

Section: Tris(pentafluorophenyl)borane(bcf)isawidelyusedlewismentioning

confidence: 99%

Tris(perfluorotolyl)borane—A Boron Lewis Superacid

et al. 2017

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Tris[tetrafluoro-4-(trifluoromethyl)phenyl]borane (BTolF) was prepared by treating boron tribromide with tetrameric F 3 CC 6 F 4 -Cu I .The F 3 CC 6 F 4 -Cu I was generated from F 3 CC 6 F 4 MgBr and copper(I) bromide.L ewis acidities of BTolF evaluated by the Gutmann-Beckett method and calculated fluoride-ion affinities are 9and 10 %, respectively,higher than that of tris(pentafluorophenyl)borane (BCF) and even higher than that of SbF 5 .T he molecular structures of BTolF and BCF were determined by gas-phase electron diffraction, that of BTolF also by single-crystal X-ray diffraction.

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Section: Tris(pentafluorophenyl)borane(bcf)isawidelyusedlewismentioning

confidence: 99%

Tris(perfluorotolyl)borane—A Boron Lewis Superacid

et al. 2017

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“…Bromodipentafluorophenylphosphane was iso-lated by using a modified procedure [44][45][46] and then reacted with hexamethyldisilazane and hydrogen peroxide to afford the pure HF 20 tpip. HF 20 tpip has been fully characterised by spectroscopic techniques and single-crystal X-ray diffraction.…”

Section: Tpip and [Ln-mentioning

confidence: 99%

Fully Fluorinated Imidodiphosphinate Shells for Visible‐ and NIR‐Emitting Lanthanides: Hitherto Unexpected Effects of Sensitizer Fluorination on Lanthanide Emission Properties

Glover

Bassett

Nockemann

et al. 2007

Chemistry A European J

168

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In this paper we demonstrate that the effect of aromatic C--F substitution in ligands does not always abide by conventional wisdom for ligand design to enhance sensitisation for visible lanthanide emission, in contrast with NIR emission for which the same effect coupled with shell formation leads to unprecedented long luminescence lifetimes. We have chosen an imidodiphosphinate ligand, N-{P,P-di(pentafluorophinoyl)}-P,P-dipentafluorophenylphosphinimidic acid (HF20tpip), to form ideal fluorinated shells about all visible- and NIR-emitting lanthanides. The shell, formed by three ligands, comprises twelve fully fluorinated aryl sensitiser groups, yet no-high energy X--H vibrations that quench lanthanide emission. The synthesis, full characterisation including X-ray and NMR analysis as well as the photophysical properties of the emissive complexes [Ln(F20tpip)3], in which Ln=Nd, Sm, Eu, Gd, Tb, Dy, Er, Yb, Y, Gd, are reported. The photophysical results contrast previous studies, in which fluorination of alkyl chains tends to lead to more emissive lanthanide complexes for both visible and NIR emission. Analysis of the fluorescence properties of the HF20tpip and [Gd(F20tpip)3] reveals that there is a low-lying state at around 715 nm that is responsible for partially quenching of the signal of the visible emitting lanthanides and we attribute it to a pi-sigma* state. However, all visible emitting lanthanides have long lifetimes and unexpectedly the [Dy(F20tpip)3] complex shows a lifetime of 0.3 ms, indicating that the elimination of high-energy vibrations from the ligand framework is particularly favourable for Dy. The NIR emitting lanthanides show strong emission signals in powder and solution with unprecedented lifetimes. The luminescence lifetimes of [Nd(F20tpip)3], [Er(F20tpip)3] and [Yb(F20tpip)3] in deuteurated acetonitrile are 44, 741 and 1111 micros. The highest value observed for the [Yb(F20tpip)3] complex is more than half the value of the Yb ion radiative lifetime.

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“…In case of pentafluorophenyl magnesium bromide and CoCl 2 , the reaction results in unsatisfactory [26][27] output, while using CuBr leads to production of tetramer [37][38] (70% output), which forms perfluorobiphenyl (68% output) when being boiled with copper (II) bromide in hexane.…”

Section: Resultsmentioning

confidence: 99%