Reaction Of Hexafluorobenzene Research Articles

Perfluorophenylcalix[4]arenes: prospective hosts for nucleophilic guests. Synthesis, structure and quantum chemical calculations

Abstract Calixarenes substituted at the upper rim by electron-deficient pentafluorophenyl groups have been synthesized by reaction of hexafluorobenzene with organolithium derivatives of calixarenes. The single crystal structures indicate stacking interactions between the two perfluorinated aromatic rings. The thermodynamic characteristics of the flattened cone-flattened cone inversion process have been studied using dynamic NMR and quantum chemical methods. The calculated activation free energy for tetra(pentafluorophenyl)-substituted species is higher than that derived for tetraphenyl calixarene. The calixarenes substituted at the upper rim by electron-deficient pentafluorophenyl groups are potential hosts for anion recognition.

Decisive Steps of the Hydrodefluorination of Fluoroaromatics using [Ni(NHC)2

The hydrodefluorination reaction of perfluorinated arenes using [Ni2(iPr2Im)4(COD)] (1; iPr2Im = 1,3-bis(isopropyl)imidazolin-2-ylidene) as a catalyst as well as stoichiometric transformations to elucidate the decisive steps for this reaction are reported. The reaction of hexafluorobenzene with 5 equiv of triphenylsilane in the presence of 5 mol % of 1 affords 1,2,4,5-tetrafluorobenzene after 48 h at 60 °C and 1,4-difluorobenzene after 96 h at 80 °C; the reaction of perfluorotoluene and 5 equiv of Et3SiH for 4 days at 80 °C results in the selective formation of 1-(CF3)-2,3,5,6-C6F4H. Stoichiometric transformations of the complexes cis-[Ni(iPr2Im)2(H)(SiPh3)] and cis-[Ni(iPr2Im)2(H)(SiMePh2)] with hexafluorobenzene at room temperature lead to the formation of trans-[Ni(iPr2Im)2(F)(C6F5)] (2) and trans-[Ni(iPr2Im)2(H)(C6F5)] (4) with elimination of the corresponding silane or fluorosilane. The reactions of the C–F activation products trans-[Ni(iPr2Im)2(F)(C6F5)] (2) and trans-[Ni(iPr2Im)2(F)(4-(CF3)C6F4)] (...

Consecutive C–F Bond Activation of Hexafluorobenzene and Decafluorobiphenyl

AbstractThe reaction of [Ni2(iPr2Im)4(COD)] (1) {iPr2Im = 1,3‐bis(isopropyl)imidazolin‐2‐ylidene} with hexafluorobenzene and decafluorobiphenyl results at room temperature in the formation of the products of a C–F bond activation reaction, i.e. [Ni(iPr2Im)2(F)(C6F5)] (2) and [Ni(iPr2Im)2(F)(C12F9)] (4). The reactions of 2 and 4 with 1 or the reactions of hexafluorobenzene and decafluorobiphenyl with 1 equiv. or excess of dinuclear 1 (stoichiometric ratio nickel/substrate > 2:1) at higher temperatures afford the complexes of a consecutive C–F bond‐activation reaction, [1,4‐{Ni(iPr2Im)2(F)}2(C6F4)] (3) and [4,4′‐{Ni(iPr2Im)2(F)}2(C12F8)] (5). Complexes 3 and 5 cleanly react in THF at room temperature with chlorotrimethylsilane and (isopropyl)(trimethylsilyl)selenane under elimination of fluorotrimethylsilane to yield the corresponding chloro and selenolato complexes [1,4‐{Ni(iPr2Im)2(X)}2(C6F4)] [X = Cl (6), iPrSe (7)] and [4,4′‐{Ni(iPr2Im)2(X)}2(C12F8)] [X = Cl (8), iPrSe (9)].

Reinvestigation on the synthesis of hexakis(phenylseleno)benzene

Reactions of hexafluorobenzene with PhSeNa in dimethylformamide (DMF) afforded 1,4-bis(phenylseleno)benzene 3 and 1,2,4,5-tetrakis(phenylseleno)benzene 4, instead of the reported product, hexakis(phenylseleno) benzene 1. Reactions of hexabromobenzene with PhSeNa in hexamethylphosphoric triamide (HMPA) afforded 1,4-bis-6, 1,2,4,5-tetrakis-7 and hexakis(phenylseleno)benzene 1. The structures of the products were established by X-ray crystallographic analysis.

Rhodium-Catalyzed Substitution Reaction of Aryl Fluorides with Disulfides: p-Orientation in the Polyarylthiolation of Polyfluorobenzenes

In the presence of a catalytic amount of RhH(PPh3)4 and 1,2-bis(diphenylphosphino)benzene, an aromatic fluoride, an organic disulfide (0.5 equiv), and triphenylphosphine (0.5 equiv) reacted in refluxing chlorobenzene to give an aryl sulfide in high yield. Since triphenylphosphine trapped fluoride atoms forming phosphine difluoride, both organothio groups of the disulfide reacted effectively, and the fluoride substituent reacted more readily than the chloride and bromide. The reaction of hexafluorobenzene and a diaryl disulfide gave 1,4-diarylthio-2,3,5,6-tetrafluorobenzene, 1,2,4,5-tetraarylthio-3,6-difluorobenzene, and hexaarylthiobenzene in a stepwise manner; pentafluorobenzene gave 1-arylthio-2,3,5,6-tetrafluorobenzene; 1,2,3,4-tetrafluorobenzene gave 1,2-diarylthio-3,6-difluorobenzene; and 1,2,4,5-tetrafluorobenzene gave 1,4-diarylthio-2-5-difluorobenzene. The polyarylthiolation reaction of polyfluorobenzenes exhibited a strong tendency to form 1,4-difluorobenzenes.

Reactivity of M(en)Cl 2 (M = Pd II/Pt II, en = 1,2-diaminoethane) with N, N′-bis(salicylidene)- p-phenylenediamine: Binding with hexafluorobenzene

Schiff base N, N′-bis(salicylidene)- p-phenylenediamine (LH 2) complexed with Pt(en)Cl 2 and Pd(en)Cl 2 provided [Pt(en)L] 2 · 4PF 6 ( 1) and Pd(Salen) ( 2) (Salen = N, N′-bis(salicylidene)-ethylenediamine), respectively, which were characterized by their elemental analysis, spectroscopic data and X-ray data. A solid complex obtained by the reaction of hexafluorobenzene (hfb) with the representative complex 1 has been isolated and characterized as 3 ( 1 · hfb) using UV–Vis, NMR ( 1H, 13C and 19F) data. A solid complex of hfb with a reported Zn-cyclophane 4 has also been prepared and characterized 5 ( 4 · hfb) for comparison with complex 3. The association of hfb with 1 and 4 has also been monitored using UV–Vis and luminescence data.

An efficient synthesis and structural aspects of hexakis(arylseleno)benzenes and hexakis(arylselenomethyl)benzenes

An efficient synthesis and structural aspects of a novel class of selenium bearing hexa-hosts by the reaction of hexafluorobenzene or hexakis(bromomethyl) benzene with RSe − ions is demonstrated. However, under identical reaction conditions, our attempts to prepare tellurium analogues by the reaction of RTe − (R = Ph or p-CH 3C 6H 4-) with hexafluorobenzene or hexakis(bromomethyl)benzene to obtain (RTe) 6C 6 and (RTeCH 2) 6C 6 proved to be difficult.

Nucleophilic Reactivity. Kinetics of Reactions between Diarylamines N-Anions and Hexafluorobenzene or Pentafluoropyridine in Dimethyl Sulfoxide2*

Rate constants of reactions between sodium salts of diarylamines N-anions and hexafluorobenzene and pentafluoropyridine in DMSO at 25°C were determined. The Bronsted factors for substrates under consideration are 0.14 and 0.34 respectively. These data evidence a considerable effect of substrate electrophilicity on the reactivity of diarylamines N-anions in the SNAr reactions. Deviations of the Bronsted plot from linearity for the reactions of hexafluorobenzene with aryl-and diarylamines N-anions may be due to the difference in internal barriers of these reactions.

Hydrogenolysis of C [sbnd]F bonds in fluorinated aromatic hydrocarbons catalysed by nickel complexes

Reactions of hexafluorobenzene, pentafluorobenzene, octafluoronaphthalene and pentafluoropyridine with the NiCl2–2,2'-bipyridine (or 1,10-phenanthroline)–Zn reductive catalytic system in DMF (or DMA) in the presence of water or ammonium chloride resulted in the products of C–F bond hydrogenolysis.

Rapid Intermolecular Carbon−Fluorine Bond Activation of Pentafluoropyridine at Nickel(0): Comparative Reactivity of Fluorinated Arene and Fluorinated Pyridine Derivatives

Reaction of hexafluorobenzene with Ni(COD)2 (COD = 1,5,-cyclooctadiene) in the presence of triethylphosphine or with Ni(PEt3)4 at room temperature results in very slow formation of trans-Ni(PEt3)2(C6F5)F (1). The X-ray crystal structure reveals a molecular complex with approximately square-planar coordination at nickel, a Ni−F distance of 1.836(5) Å and a Ni−C distance of 1.878(7) Å. Analogous reactions with pentafluoropyridine and 2,3,5,6-tetrafluoropyridine proceed much faster. Both reactions yield C−F activation products analogous to 1 in which a single regioisomer is dominant. The crystal structure of trans-Ni(PEt3)2(C5HF3N)F (3) shows that the trifluoropyridyl ligand is metalated at the 2-position. The Ni−F and Ni−C distances are 1.856(2) and 1.869(4) Å, respectively. In the structures of both 1 and 3, the plane of the aryl ring is perpendicular to the nickel coordination plane. These structures provide the first values of nickel-fluorine distances at square-planar Ni(II). The reaction of Ni(COD)2 with PEt3 and 3,5-dichloro-2,4,6-trifluoropyridine yields exclusively trans-Ni(PEt3)2(C5ClF3N)Cl (4), the product of C−Cl activation with the metal at the 3-position of the ring. The corresponding reaction with 2,3,4,5,6,-pentafluorostyrene results in rapid formation of the alkene coordination product, Ni(PEt3)2(η2-CH2CHC6F5) (6). The crystal structure of 6 shows the typical trigonal Ni(0) geometry with the coordinated atoms almost perfectly coplanar with the nickel. The Ni−C distances average 1.960(6) Å; the P−Ni−P angle is 115.0(1)°. Reaction with pentafluorobenzene and methoxypentafluorobenzene yield C−F activation products very slowly with little regioselectivity. The studies reported in this paper demonstrate that intermolecular C−F activation of a fluoroaromatic can take place rapidly and in good yield at a first row transition metal through the suitable choice of substrate.

Reaction of hexafluorobenzene with trimethylsilyl ethers

Hexafluorobenzene reacts readily with a variety of trimethylsilyl ethers ROSiMe 3 (R=CF 3CH 2, FCH 2CH 2, H(CF 2) n ,CH 2 ( n=2, 4), CF 3(CF 2) 6CH 2, CF 3(CF 2) 5CH 2CH 2, Me 3SiOCH 2CH 2, C 6F 5OCH 2CH 2, C 6H 5, 4-FC 6H 4) to give from mono- to hexapolyfluoroalkoxy- and polyfluoroaryloxy-benzenes. The structure of C 6(OCH 2CF 3) 6 has been confirmed by single-crystal X-ray analysis. The perfluorinated ether C 6F 5OCF 2CF 3 may be synthesized from C 6F 5OCH 2CF 3 by chlorination and subsequent fluorination with SbF 3/SbCI 5. The chlorination of 5,6,7,8-tetrafluoro-1,4-benzodioxane is also discussed.

Reactions of Hexafluorobenzene and Pentafluorophenol Catalyzed by Irradiated TiO2 in Aqueous Suspensions

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTReactions of Hexafluorobenzene and Pentafluorophenol Catalyzed by Irradiated TiO2 in Aqueous SuspensionsC. Minero, E. Pelizzetti, R. Terzian, and N. SerponeCite this: Langmuir 1994, 10, 3, 692–698Publication Date (Print):March 1, 1994Publication History Published online1 May 2002Published inissue 1 March 1994https://doi.org/10.1021/la00015a017RIGHTS & PERMISSIONSArticle Views223Altmetric-Citations19LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (6 MB) Get e-Alerts Get e-Alerts

C–F bond activation by iridium(I). A unique process involving P–C bond cleavage, P–F bond formation and net retention of oxidation state

Reaction of hexafluorobenzene with MeIr(PEt3)3 results in a unique process involving C–F bond cleavage, P–C bond cleavage and P–F bond formation, yielding the crystallographically characterized iridium (I) complex 2.

Reactions of perfluoroaromatic compounds with ethereal solutions of methylmagnesium iodide in the presence of silver(I) and copper(I) salts

The reactions of hexafluorobenzene, octafluorotoluene, decafluorodiphenyl, and octafluoronaphthalene with ethereal solutions of methylmagnesium iodide in the presence of AgCl or CuI gave the products of the methylation and 1-ethoxy-ethylation of the perfluorinated substrates, whose formation has been suggested to occur with participation of free radicals. Substitution of fluorine atoms by the 1-ethoxyethyl radicals in C 6F 5CF 3 and C 6F 5C 6F 5 proceeds with predominant para-orientation; in C 10F 8, 1- and 2-orientations take place to an equal extent, whereas the methyl radicals attack mainly the 1-position of octafluoronaphthalene and show a low selectivity in the reaction with octafluorotoluene.

Synthesis of hexakis(aryloxy)benzenes: x-ray analysis of hexakis (phenyloxy) benzene and of the acetonitrile clathrate of hexakis (3,5-dimethylphenyloxy) benzene

Hexakis (aryloxy) benzenes (I)-(IV), representatives of a new class of molecule, have been prepared by reaction of hexafluorobenzene with the sodium salt of the appropriate phenol in 1,3-dimethyl-2-imidazolidinone (DMEU) as solvent. X-ray analyses of parent (I) and of the acetonitrile clathrate of (II) are described, a novel edge-on interaction between host and guest being found in the latter.

Fluoro-substituted benzo-crown polyethers

3′,4′,5′,6′-Tetrafluorobenzo-15-crown-5 1 and 3′,4′,5′,6′-tetrafluorobenzo-18-crown-6 2 are readily prepared by reaction of hexafluorobenzene with tetra- and pentaethylene glycol, respectively, and show markedly reduced salt-extraction capability compared to hydrocarbon analogues.

Reactions of hexafluorobenzene and pentafluorophenylamino compounds with amides and anilides (steric effects)

Contrary to N-lithium-N-methylanilide and N-lithium-diphenylamide, trimethyl-N-lithium-N-phenyl-silylamide gave with hexafluorobenzene in molar ratio 2:1, only the monosubstituted compound. Competitive reactions gave the following order of reactivity toward N-lithiumanilide: 2,3,4,5,6-pentafluorotriphenylamine > 2,3,4,5,6-pentafluoro-N-methyl-diphenylamine > hexafluorobenzene ⪢ trimethyl-2,3,4,5,6-pentafluoro-N,N-diphenyl-silylamine. A reason for the low reactivity of trimethyl-2,3,4,5,6-pentafluoro-N,N-diphenyl-silylamine against aromatic amides has been proposed. Some new aromatic amines have been synthesized, among them hexamethyl-N-pentafluorophenyl-disilylamine.

Homolytic reactions of polyfluoroaromatic compound. Part XI. Confirmation of the proposed mechanism of phenylation of polyfluoroaromatic substrates

The derivatives of dihydrobiphenyl, which were predicted [1,2] to be formed in the thermolysis of benzoyl peroxide in polyfluoroaromatic compounds and which arose from transesterification, have been identified in the reactions of hexafluorobenzene and of octafluorotoluene with this peroxide. The presence of 1,4-dihydro-1,2,3,4,4,5,6-heptafluorobiphenyl (or its positional isomer, 1,2-dihydro-1,2,2,3,4,5,6-heptafluorobiphenyl) in such reaction mixtures also explains the formation of 3,4′- bis (phenyl)-octafluorobiphenyl in the dehalogenation products of the polynuclear residue from the reaction in hexafluorobenzene. Fluorine migration [3] does not need to be postulated. The yield of 2,3,4,5,6-pentafluorobiphenyl from the thermal decomposition of phenylazotriphenylmethane (PAT) in hexafluorobenzene at 80° is generally increased by the presence of a variety of hydrogen donors. Larger amounts of additive increase the yield of biaryl with respect to PAT, but not usually with respect to the additive. These results are consistent with the mechanism of arylation of polyfluoroaromatic compound previously suggested [1,2].

The reaction of hexafluorobenzene with peroxydisulfuryl difluoride and chlorine fluorosulfate

The reaction of hexafluorobenzene with peroxydisulfuryl difluoride and chlorine fluorosulfate

Reactions of hexafluorobenzene with some organometallic reagents

Abstract The inverse addition of trichloro-2-thienyl-lithium to hexafluorobenzene in THF or ether has given 1,4-bis(trichloro-2-thienyl) tetrafluorobenzene in addition to the tetrakis(trichloro-2-thienyl)difluorobenzene. n-Butyl-lithium with hexafluorobenzene gave mono, bis tris and tetrakis compounds whereas t-BuLi afforded only 1,4-bis(t-butyl)tetrafluorobenzene in excellent yield. Other organolithium and organomagnesium reagents gave the expected products. IR, 19 F NMR and UV spectral data are presented for the several new compounds.