363-72-4Relevant articles and documents
Heterolytic bond activation at gold: Evidence for gold(iii) H-B, H-Si complexes, H-H and H-C cleavage
Rocchigiani, Luca,Budzelaar, Peter H. M.,Bochmann, Manfred
, p. 2633 - 2642 (2019)
The coordinatively unsaturated gold(iii) chelate complex [(C^N-CH)Au(C6F5)]+ (1+) reacts with main group hydrides H-BPin and H-SiEt3 in dichloromethane solution at -70 °C to form the corresponding σ-complexes, which were spectroscopically characterized (C^N-CH = 2-(C6H3But)-6-(C6H4But)pyridine anion; Pin = OCMe2CMe2O). In the presence of an external base such as diethyl ether, heterolytic cleavage of the silane H-Si bond leads to the gold hydrides [{(C^N-CH)AuC6F5}2(μ-H)]+ (2+) and (C^N-CH)AuH(C6F5) (5), together with spectroscopically detected [Et3Si-OEt2]+. The activation of dihydrogen also involves heterolytic H-H bond cleavage but requires a higher temperature (-20 °C). H2 activation proceeds in two mechanistically distinct steps: the first leading to 2 plus [H(OEt2)2]+, the second to protonation of one of the C^N pyridine ligands and reductive elimination of C6F5H. By comparison, formation of gold hydrides by cleavage of suitably activated C-H bonds is very much more facile; e.g. the reaction of 1·OEt2 with Hantzsch ester is essentially instantaneous and quantitative at -30 °C. This is the first experimental observation of species involved in the initial steps of gold catalyzed hydroboration, hydrosilylation and hydrogenation and the first demonstration of the ability of organic C-H bonds to act as hydride donors towards gold.
The fluorine-pentafluorophenyl substitution reaction in anhydrous hydrogen fluoride (aHF): A new interesting methodical approach to synthesize pentafluorophenylxenonium salts
Frohn, Hermann-Josef,Schroer, Thorsten
, p. 259 - 264 (2001)
In anhydrous hydrogen fluoride (aHF) (heterogeneous reaction) B(C6F5)3 transfers all the three aryl groups to XeF2 forming [C6F5Xe]+ salts. Upon addition of KF, the [C6F5Xe] [HF2] salt was isolated in 78.7% yield. [C6F5Xe] [HF2] dissolved in MeCN exhibits significant cation-anion interactions and decomposes within 14 days at 20°C. The acidity of the aHF solvent determines the nature of the products in the reaction of XeF2 with B(C6F5)3. The reaction path of this new methodical approach of fluorine-aryl substitution in aHF is discussed.
Synthesis and Reactivity of a Low-Coordinate Iron(II) Hydride Complex: Applications in Catalytic Hydrodefluorination
Hein, Nicholas M.,Pick, Fraser S.,Fryzuk, Michael D.
, p. 14513 - 14523 (2017)
A low-coordinate iron hydride complex bearing an unsymmetrical NpN (enamido-phosphinimine) ligand scaffold was synthesized and fully characterized. Insertion reactivity with azobenzene, 3-hexyne, and 1-azidoadamantane was explored, and the isolated products were analogous to previously reported β-diketiminate iron hydride insertion products. Surprisingly, the NpN iron hydride displays unprecedented reactivity toward hexafluorobenzene, affording an NpN iron fluoride complex and pentafluorobenzene as products. The NpN iron hydride is a precatalyst for catalytic hydro-defluorination of perfluorinated aromatics in the presence of silane. Kinetic studies indicated that the rate-determining step during catalysis involved silane.
Promotion of reductive elimination reaction of diorgano(2,2′-bipyridyl)nickel(II) complexes by electron-accepting aromatic compounds, Lewis acids, and Bronsted acids
Yamamoto, Takakazu,Abla, Mahmut,Murakami, Yasuharu
, p. 1997 - 2009 (2002)
Reductive elimination of R-R from dialkyl(2,2′-bipyridyl)nickel(II), [NiR2(bpy)] 1 (R = CH3 (1a), C2H5 (1b), n- C3H7 (1c)), caused by π-coordination of electron-accepting aromatic compounds and reductive elimination of Ar-Ar from [NiAr2(bpy)] 2 (Ar = C6F5 (2a) and pyrazolyls (2b and 2c)) promoted by electron-accepting aromatic compounds, Lewis acids, and Bronsted acids have been investigated. 1H-NMR and kinetic data indicate that π-coordination of the electron-accepting aromatic compound to [NiR2(bpy)] leads to the reductive elimination of R-R. The rate of the reductive elimination obeys the second-order rate law, -d[1]/dt = k[1][electron-accepting aromatic compound]. Plots of log k vs Σσp of the electron-accepting aromatic compound give a line with a slope of 1.8. Bronsted acids cause reductive elimination of Ar-Ar from 2 selectively under several reaction conditions (e.g., 2a with CF3COOH in air and 2b with HBr). The reductive elimination reaction of 2a caused by CF3COOH obeys the second-order rate law, -d[2a]/dt = k′[2a][CF3COOH], in air. The reaction of 2b with H2SO4 requires O2, giving the rate equation, -d[2b]/dt = k″[2b]2[O2]; k″ increases with [H2SO4], reaching a maximum value at a high [H2SO4]. UV-vis spectroscopy reveals the presence of the following equilibrium: 2b + H2SO4 ? 2b·H2SO4, and the equilibrium constant Ka is evaluated as Ka = [2b·H2SO4]/ ([2b][H2SO4]) = 47 M-1 at 300.5 K. UV-vis data give information about the electronic states of 2 and the 2b-Bronsted acid adduct. Poly(6-hexylpyridine-2,5-diyl) with a higher molecular weight has been prepared according to the basic information.
Promoting Difficult Carbon–Carbon Couplings: Which Ligand Does Best?
Gioria, Estefanía,del Pozo, Juan,Martínez-Ilarduya, Jesús M.,Espinet, Pablo
, p. 13276 - 13280 (2016)
A Pd complex, cis-[Pd(C6F5)2(THF)2] (1), is proposed as a useful touchstone for direct and simple experimental measurement of the relative ability of ancillary ligands to induce C?C coupling. Interestingly, 1 is also a good alternative to other precatalysts used to produce Pd0L. Complex 1 ranks the coupling ability of some popular ligands in the order PtBu3>o-TolPEWO-F≈tBuXPhos>P(C6F5)3≈PhPEWO-F>P(o-Tol)3≈THF≈tBuBrettPhos?Xantphos≈PhPEWO-H?PPh3according to their initial coupling rates, whereas their efficiency, depending on competitive hydrolysis, is ranked tBuXPhos≈PtBu3≈o-TolPEWO-F>PhPEWO-F>P(C6F5)3?tBuBrettPhos>THF≈P(o-Tol)3>Xantphos>PhPEWO-H?PPh3. This “meter” also detects some other possible virtues or complications of ligands such as tBuXPhos or tBuBrettPhos.
The Pentafluorophenylxenon(II) Cation: +; The First Stable System with a Xenon-Carbon Bond
Frohn, Hermann J.,Jakobs, Stephanus
, p. 625 - 627 (1989)
Pentafluorophenylxenon(II) pentafluorophenyltrifluoroborate, +-, can be prepared analogously to pentafluorophenylhalogen(III) and (V) fluorides, C6F5HalF2 and C6F5HalF4 (with Hal=Br or I), by nucleophilic displacement of fluorine in XeF2 using B(C6F5)3 as an aryl-transfer reagent; the resulting colourless solid with a stable xenon-carbon bond is characterised in solution by (129)Xe and (19)F n.m.r. and chemically as an electrophilic transfer reagent for pentafluorophenyl groups.
Reaction of difluoromethyl pentafluorophenyl sulfoxide with nucleophiles
Koshcheev,Maksimov,Platonov,Shelkovnikov
, (2017)
Reactions of 1-(difluoromethanesulfinyl)pentafluorobenzene with sodium methoxide, sodium phenoxide, potassium hydrosulfide, and methylamine resulted in substitution of fluorine atom in the 4-position (in the reaction with methylamine, also in the 2-positi
Grignard exchange reaction using a microflow system: From bench to pilot plant
Wakami, Hideo,Yoshida, Jun-Ichi
, p. 787 - 791 (2005)
The Grignard exchange reaction of ethylmagnesium bromide (EtMgBr) and bromopentafluorobenzene (BPFB) to give pentafluorophenylmagnesium bromide (PFPMgBr) was carried out using small- and medium-scale microflow systems consisting of a micromixer and a microheat exchanger. The results indicate that the microflow systems are quite effective. On the basis of the data obtained, a pilot that involves the Toray Hi-mixer connected to a shell and tube microheat exchanger was constructed. Continuous operation for 24 h was accomplished without any problem to obtain pentafluorobenzene (PFB) after protonation (92% yield).
Reductive elimination of C6F5-C6F 5 in the reaction of bis(pentafluorophenyl)palladium(ii) complexes with protic acids
Koizumi, Take-Aki,Yamazaki, Atsuko,Yamamoto, Takakazu
, p. 3949 - 3952 (2008)
Reductive elimination of C6F5-C6F 5 from cis-[Pd(C6F5)2L] (L = cod, bpy, and dppb) was promoted by Bronsted acids. HNO3 is a convenient acid for the formation of C6F5-C 6F5 from [Pd(C6F5) 2(cod)]. The products are controlled by the auxiliary ligand.
Synthesis, reactivity and X-ray crystal structure of tris(pentafluorophenyl)silanol (C6F5)3SiOH
Cariati, Elena,Carlucci, Lucia,D'Alfonso, Giuseppe,Giovenzana, Tommaso,Lucenti, Elena,Maggioni, Daniela,Sironi, Angelo
, (2022/01/26)
Tris(pentafluorophenyl)silanol (C6F5)3SiOH was prepared from the corresponding chlorosilane (C6F5)3SiCl by an unconventional controlled hydrolysis. The X-ray structure and the reactivity of
