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1.
Although fluorine containing ketones (RfC(O)Rf and RfC(O)R, Rf = perfluoroalkyl) have been prepared from the reaction between organolithium reagents and perfluoroalkyl esters, the reaction has not found general applicability. Variable yields of ketones and co-production of secondary and tertiary alcohol by-products have in most instances been experienced. We have examined in more detail the factors e.g., temperature, mode of addition and perfluoroalkyl ester structure which influence ketone product and by-products formation. By controlling experimental conditions excellent yields of C6H5C(O)Rf compounds can be attained. A lithium salt of a hemiketal (II) has been isolated and shown to be the active intermediate in the production of the ketone. The stability of the salt and its potential reaction with the solvent dictates the type of reaction products. Low temperature favors stability of the lithium salt of the hemiketal whereby high yields of ketones are produced on hydrolysis. 相似文献
2.
Joanne E. Stanley Anthony C. Swain Kieran C. Molloy David W. H. Rankin Heather E. Robertson Blair F. Johnston 《应用有机金属化学》2005,19(5):644-657
Perfluoroalkytin compounds R(4−n)Sn(Rf)n (R = Me, Et, Bu, Rf = C4F9, n = 1; R = Bu, Rf = C4F9, n = 2, 3; R = Bu, Rf = C6F13, n = 1) have been synthesized, characterized by 1H, 13C, 19F and 119Sn NMR, and evaluated as precursors for the atmospheric pressure chemical vapour deposition of fluorine‐doped SnO2 thin films. All precursors were sufficiently volatile in the range 84–136 °C and glass substrate temperatures of ca 550 °C to yield high‐quality films with ca 0.79–2.02% fluorine incorporation, save for Bu3SnC6F13, which incorporated <0.05% fluorine. Films were characterized by X‐ray diffraction, scanning electron microscopy, thickness, haze, emissivity, and sheet resistance. The fastest growth rates and highest quality films were obtained from Et3SnC4F9. An electron diffraction study of Me3SnC4F9 revealed four conformations, of which only the two of lowest abundance showed close F Sn contacts that could plausibly be associated with halogen transfer to tin, and in each case it was fluorine attached to either the γ‐ or δ‐carbon atoms of the Rf chain. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
3.
Xiangli Liu Yougang Mao Errol V. Mathias Collin Ma Osmundo Franco Yong Ba Julia A. Kornfield Tieli Wang Lijun Xue Bing-Sen Zhou Yun Yen 《Journal of Sol-Gel Science and Technology》2008,45(3):269-278
Hydrogel formed by fluoroalkyl double-ended polyethylene glycol (Rf-PEG) micelles was studied to assess its properties to encapsulate a hydrophobic electron spin labeled drug, Chlorambucil–Tempol
adduct (CT), and to control and sustain the drug release. The drug loaded hydrogel samples were characterized with variable-temperature
dependent EPR experiment, and EPR theoretical lineshape analysis. It was found that CT molecules reside in the hydrophobic
Rf-cores/IPDU shells of the Rf-PEG micelles and the maximum molecular-level loading capacity was estimated to be 18.8 mg per gram of the Rf-PEG. It has been known that Rf-PEG hydrogel with certain molecular masses for the fluoroalkyl group and the PEG chain shows properties of sol/gel phase
coexistence and surface erosion, which represent the favorable condition for a pharmaceutical depot to control the kinetics
of drug release. To evaluate the Rf-PEG’s biocompatibility and kinetics of the drug release, a cell proliferation assay was carried out on human oropharyngeal
carcinoma (KB) cells. The results show that Rf-PEG is biocompatible and able to release CT to the cell media with a constant equilibrium concentration independent of the
amount of CT loaded hydrogel. 相似文献
4.
Prof. Dr. Yang Li Dr. Helfried Neumann Prof. Dr. Matthias Beller 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(30):6784-6788
Introducing (per)fluoroalkyl groups into arenes continues to be an interesting, but challenging area in organofluorine chemistry. We herein report an ortho-selective C−H perfluoroalkylation including trifluoromethylations of anilines and indoles without the need of protecting groups using RfI and RfBr as commercially available reagents. The availability and price of the starting materials and the inherent selectivity make this novel methodology attractive for the synthesis of diverse (per)fluoroalkylated building blocks, for example, for bioactive compounds and materials. 相似文献
5.
The additivity of selected chromatographic data with a group of ortho derivatives of phenol, aniline, benzaldehyde, and nitrobenzene has been proved with the help of the theoretical approach developed by Snyder (1–5), and this concept is assumed to be useful in the attempt to predict the Rf, values of substances with known structures or in elucidating such structures with compounds having known Rf, values. 相似文献
6.
《化学:亚洲杂志》2017,12(18):2369-2373
Octaalkenyl calix[4]pyrrole ((CH2=CH(CH2)2)8C4P) is highly useful for the postfunctionalization of different calix[4]pyrroles with desired functionalities. Functionalization with perfluoroalkyl chains [CF3(CF2)n ; Rfn ] gave perfluoroalkyl calix[4]pyrroles (Rfn (CH2)4)8C4P; n =6, 8), having >60 % fluorine content, which created a hydrophobic environment inside the calix[4]pyrrole cavity and recognized fluoride and chloride ions in solution as well as in the solid state. The fluoride ion is extracted efficiently from aqueous CsF and TBAF solutions by using (Rf6(CH2)4)8C4P, as droplets. The fluorinated chain generated a hydrophobic environment which broke the hydration shell associated with the anion and separated out fluoride ions as droplets from aqueous medium. Furthermore, the fluoride ions competitively replaced chloride ions from the (Rf6(CH2)4)8C4P cavity. 相似文献
7.
Harinarayanan Puliyalil Nina Recek Gregor Filipič Miha Čekada Ivan Jerman Miran Mozetič Sabu Thomas Uroš Cvelbar 《Surface and interface analysis : SIA》2017,49(4):334-339
Achieving optimal hydrophobicity of polymer materials especially polymer–matrix composites is important for many material applications. Herein the interplay of factors determining hydrophobic surface is presented during CF4 plasma treatments which lead to functionalization as well as selective polymer–matrix etching. The continuous exposure to plasma reactive species induces functionalization and etching on the surface, which decides the surface morphology and surface chemistry. Consequently, exothermic processes during the plasma–surface interactions are another important factor which influences the surface chemistry and etching rate of the material. The results demonstrate that despite etching and increasing surface roughness, the major contribution to hydrophobic character is dependent on the number of carbon atoms populated with fluorine, whereas the temperature is a deciding factor for type of created bonds. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
8.
Maria Carmelita Z. Kasuya 《Journal of fluorine chemistry》2011,132(3):202-206
Incubation of animal cells in the presence of amphiphilic glycosides having a lactoside residue (hydrophilic moiety) and various kinds of perfluoroalkyl chain (hydrophobic moiety) resulted to glycosylation of the saccharide chain by cellular enzymes and afforded glycolipid-like compounds. The amounts of amphiphilic glycoside and glycolipid-like compounds found in the cell and culture medium fractions, respectively, varied depending on the fluorine content of the perfluoroalkyl chain. To investigate further, the hydrophobicity of the perfluoroalkyl chain was estimated from the critical micelle concentration values and was found to be 1.5 times larger in hydrophobicity than the hydrocarbon chain [CF2 = 1.5CH2]. Liposomes resembling cells in size were also prepared and the amphiphilic glycosides were introduced. Results showed a positive correlation between hydrophobicity and localization of amphiphilic glycoside into liposomes. The amount of amphiphilic glycosides localized in liposomes increased with increasing hydrophobicity that is attributed mainly to the fluorine content of the aglycon. In spite of the low affinity of fluorous chain for hydrocarbon chain, the amphiphilic fluorous compounds showed high affinity for cell membrane that is composed of amphiphilic phospholipids. 相似文献
9.
Structural relaxation for simple and more complex thermal histories is described by a phenomenological model based on a non-exponential
relaxation function, the reduced-time concept and the nonlinear structural contribution to the relaxation time. The history,
development of experimental techniques and data analysis is described. It is shown that the volume and enthalpy relaxation
response can conveniently be compared on the basis of a fictive relaxation rate, R
f. A simple equation relating R
f and the parameters of the phenomenological model is given. The calculated data for moderate departures from equilibrium are
in good agreement with our experiments and data previously reported in the literature.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
10.
Treatment of perfluoro-n-octanonitrile with phenylphosphine gave tetraphenyltetraphosphine and a spectrum of reduction and interaction products. Fifteen compounds were identified. The imine, (RfC7F15) RfCHNH, and the amine, RfCH2NH2, were the primary reduction products. Secondary phosphorus-free products, some formed following ammonia evolution, were the following: RfCHNCH2Rf, RfCH2CH(NH2)Rf, RfC(NH)NCRf(NH2), RfCH2NHCRf(NH), (RfCN)3, RfCHNCRfNCRf(NH), RfCH2NCRfNHCH2Rf, and RfCH2NCRfNHCRf(NH). Only three phosphorus-containing materials were definitely identified: RfCH(NH2)P(C6H5)H, RfCH[P(C6H5)H]NCHRf, and RfC(NH)P(C6H5)CRf(NH). Depending on reaction conditions, specific phosphorus-containing compounds could be preferentially produced. All the structure assignments are based solely on mass spectral breakdown patterns, since pure compounds were not isolated. 相似文献
11.
H. Meinert 《Macromolecular Symposia》1994,82(1):201-214
Electrochemical fluorination (ECF) of various heterocyclic compounds has been investigated. α,ω-Dimorpholinoalkanes of different chain length (n = 1-6) and of morpholinocyclohexene gave the perfluoro derivatives in yields up to 45%. The crystal and molecular structures of the perfluorinated compounds are presented. The mechanism of ECF for these compounds is discussed on the basis of a steric model. Perfluorocarbon emulsions of second generation were prepared by means of F-dimorpholines and F-cyclohexylmorpholine, acting both as oxygen carriers and as interfacial active compounds (IFACs). The stabilizing effect of these IFACs is interpreted. Semifluorinated alkanes, RfRh, are chemically inert and non-toxic. They are useful for blood substitutes in two ways: as co-surfactants to stabilize emulsions with perfluorocarbons and as oxygen carriers instead of perfluorocarbons. The high density of perfluorocarbons cause problems in some field of application in medicine. Therefore symmetrical diethers of the type RF(CH2)mO(CH2)nO(CH2)mRF were synthesized. These are inert and biocompatible compounds. Diethers with long RF-tail and long hydrocarbon spacer are ideal solubilizers for perfluorocarbons with hydrocarbons and vice versa. The diethers with short hydrocarbon spacer and long RF-tail can be applied in biological systems, because they are not soluble in lipid tissues. Perfluorocarbons (e. g. F-decalin, F-octane) are used as medical tools in ophthalmology, their purity is essential. Not totally fluorinated compounds (1 H-perfluoroalkanes, α,ω-dihydrogenoperfluoroalkanes) are characterized and discussed. 1H-perfluoroalkane is also formed by nucleophilic attack on perfluoroalkyl halide. 相似文献
12.
Kazuyuki Sato 《Journal of fluorine chemistry》2010,131(1):86-90
Treatment of silyl enol ethers of various carbonyl compounds with Et2Zn and fluoroalkyl halides (Rf-X) in the presence of RhCl(PPh3)3 in DME gave the corresponding α-Rf carbonyl compounds. A highly reactive alkyl-rhodium complex which was derived from RhCl(PPh3)3 and Et2Zn must be crucial in this reaction by accelerating the reaction rate and improving the yields dramatically. This reaction overcomes difficulties on the synthesis of α-Rf carbonyl compounds due to inverse polarization of Rf-X. 相似文献
13.
The introduction of low-intermolecular-force, aliphatic fluorocarbon groups into siloxane polymers has produced a variety of useful, low surface tension materials including Rf(CH2)2SiO3/2 self-assembled polymer monolayers and silsesquioxane polymers, and [Rf(CH2)2MeSiO]n siloxanes. The surface tensions of such materials measured by the contact angle approaches of Owens-Wendt and Girifalco-Good-Fowkes-Young are reviewed and compared with the direct determination from work of adhesion studies based on the Johnson, Kendall and Roberts theory. The lowest surface tension fluorosilicones available are as oleophobic and hydrophobic as any known fluoropolymer. The most efficient, effective incorporation of fluorine in these fluorosilicones is generally achieved with the CF3(CF2)3(CH2)2 group, making these nonafluorohexyl-containing species the most commercially attractive. 相似文献
14.
Joon T. Park John R. Shapley Kwangyeol Lee Hyunjoon Song 《Journal of Cluster Science》2000,11(2):343-358
A comprehensive review of the hydrocarbon derivative chemistry of WOs3 mixed-metal cluster compounds including synthesis, reactivity, ligand transformation, and solution dynamics is presented. 相似文献
15.
Mary F. Mahon Kieran C. Molloy Joanne E. Stanley David W. H. Rankin Heather E. Robertson Blair F. Johnston 《应用有机金属化学》2005,19(5):658-671
Nine organotin fluorocarboxylates RnSnO2CRf (n = 3, R = Bu, Rf = CF3, C2F5, C3F7, C7F15; R = Et, Rf = CF3, C2F5; R = Me, Rf = C2F5; n = 2, R = Me, Rf = CF3) have been synthesized; key examples have been used to deposit fluorine‐doped SnO2 thin films by atmospheric pressure chemical vapour deposition. Et3SnO2CC2F5, in particular, gives high‐quality films with fast deposition rates despite adopting a polymeric, carboxylate‐bridged structure in the solid state, as determined by X‐ray crystallography. Gas‐phase electron diffraction on the model compound Me3SnO2CC2F5 shows that accessible conformations do not allow contact between tin and fluorine, and that direct transfer is therefore unlikely to be part of the mechanism for fluorine incorporation in SnO2 films. The structure of Me2Sn(O2CCF3)2(H2O) has also been determined and adopts a trans‐Me2SnO3 coordination sphere about tin in which each carboxylate group is monodentate. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
16.
G.A. Razuvaev M.N. Bochkarev L.V. Pankratov 《Journal of organometallic chemistry》1983,250(1):135-143
Metallic lithium and dibenzenechromium displace thallium from (Rf3Ge)3HgTl·1.5DME (Rf = C6F5, DME = 1,2-dimethoxyethane) to give (Rf3Ge)3HgLi·3DME and [(Rf3Ge)4Hg][Cr(C6H6)2]2, respectively. Reactions of thallium germylmercurate with halides of metals and organometallics in DME/EtOH solution produce ionic compounds of [(Rf3Ge)3Hg]? M+ type, which (depending on “M”) (a) may be isolated as pure compounds, (b) disproportionate, (c) form covalent derivatives Rf3Ge-m or (d) undergo alcoholysis. A general scheme for the reactions has been proposed. 相似文献
17.
Kulbinder K. Banger Alan K. Brisdon Christopher J. Herbert Hana Ali Ghaba Ian S. Tidmarsh 《Journal of fluorine chemistry》2009,130(12):1117-1129
A review of the methods available for the preparation of monodentate P(III) compounds containing fluoroalkenyl, fluoroalkynyl and fluoroalkyl groups is given. The synthesis, properties and coordination chemistry of some fluoroalkenyl- and fluoroalkynyl-containing phosphines derived from HFC-134a (CF3CH2F) and HFC-245fa (CF3CH2CH2F) is summarised. The development of the reaction between trimethylsilyl-containing phosphines and RfI which provides a general method by which bulky fluoroalkyl groups, such as i-C3F7, t-C4F9, c-C6F11, can be readily introduced into phosphorus(III) centres is reported. Together these methods provide a way of generating P(III) systems of the type R3−nP(Rf)n capable of possessing a wide range of steric and electronic properties. 相似文献
18.
D. Nurok R. M. Becker M. J. Richard P. D. Cunningham W. B. Gorman C. L. Bush 《Journal of separation science》1982,5(7):373-376
ΔRf, the separation between a pair of compounds on a thin layer chromatographic plate, can be predicted as a function of solvent composition for certain binary systems. This allows the prediction of optimum solvent composition for separating a mixture of compounds by thin layer chromatography. A new solvent polarity ranking, based on calculation of ΔRf is described. 相似文献
19.
Summary The retention behaviour of some substituted benzoic acids was tested on reversed-phase pre-coated plates in the presence of ammonium bromide and various tetraalkylammonium compounds with different alkyl chain lengths.It could be shown that the Rf values of the test compounds decrease in the absence and in the presence of ion-pair reagents with increasing water content of the eluent. The Rf values of the strongly acidic substituted benzoic acids decrease with both increasing concentration of the ion-pair reagent and with increasing chain length of the tetraalkylammonium compounds.Changing the inorganic counter-ions had no real influence on the separation and the size of Rf values when using tetramethylammonium compounds as ion-pair reagents. 相似文献