首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
A more convenient synthesis of the perfluoro alkyl hypofluorite (F3C)3COF as well as the hitherto unknown (C2F5)(F3C)2COF compound is reported. Both hypofluorites can be prepared by use of the corresponding tertiary alcohols RFOH and elemental fluorine in the presence of CsF. An appropriate access to these highly reactive hypofluorites is crucial. The hypofluorites are then transferred into their corresponding perfluoro bisalkyl peroxides RFOORF [RF=(F3C)3C, (C2F5)(F3C)2C] by treatment with partially fluorinated silver wool. NMR, gas-phase infrared, and solid-state Raman spectra of the perfluoro bisalkyl peroxides are presented and their chemical properties are discussed.  相似文献   

2.
High‐temperature gas‐phase, solvent‐ and catalyst‐free reaction of naphthalene with an excess of RFI reagent (RF?CF3, C2F5, n‐C3F7, and n‐C4F9) was used for the first time to produce a series of highly perfluoroalkylated naphthalene products NAPH(RF)n with n=2–5. Four 95+ % pure 1,3,5,7‐NAPH(RF)4 with RF?CF3, C2F5, n‐C3F7, and n‐C4F9 were isolated using a simple chromatography‐free procedure. These new compounds were fully characterized by 19F and 1H NMR spectroscopy, X‐ray crystallography (for RF?CF3 and C2F5), atmospheric‐pressure chemical ionization mass spectrometry, and cyclic and square‐wave voltammetry. DFT calculations confirm that the proposed synthesis yields the most stable isomers that have not been accessed by alternative preparation techniques.  相似文献   

3.
Fluoroalkyl end‐capped acrylic acid oligomer [RF‐(ACA)n‐RF] reacted with tetraethoxysilane and silica nanoparticles in the presence of low molecular weight aromatic compounds [ Ar‐H ] such as cetylpyridinium chloride (CPC) and bisphenol AF under alkaline conditions to afford RF‐(ACA)n‐RF/SiO2 nanocomposites‐encapsulated Ar‐H in 47–94% isolated yields. These fluorinated silica nanocomposites‐encapsulated Ar‐H can exhibit no weight loss behavior corresponding to the contents of Ar‐H after calcination at 800 °C under atmospheric conditions, although fluoroalkyl end‐capped acrylic acid oligomer in the nanocomposites decomposed completely under similar conditions. UV‐vis spectra of well‐dispersed methanol solutions of RF‐(ACA)n‐RF/SiO2/CPC nanocomposites before calcination show that CPC can be encapsulated into fluorinated silica nanocomposites with encapsulated ratios: 23–43%. The fluorinated nanocomposites after calcination was found to exhibit a higher antibacterial activity related to the presence of CPC in the composites. Encapsulated bisphenol AF into RF‐(ACA)n‐RF/SiO2 nanocomposites before and after calcination at 800 °C can exhibit a good releasing ability toward methanol with released ratios: 48 and 26%, respectively. 1H MAS NMR, HPLC analysis, and LC‐MS spectra of RF‐(ACA)n‐RF/silica nanocomposites‐encapsulated bisphenol AF also showed the presence of bisphenol AF in the nanocomposites even after calcination at 800 °C under atmospheric conditions. These findings suggest that CPC and bisphenol AF can exhibit a nonflammable characteristic in the fluorinated silica nanocomposites. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011  相似文献   

4.
The study of perfluoroalkyl metal complexes is key to understand and improve metal-promoted perfluoroalkylation reactions. Herein, we report the synthesis of the first gold complexes with primary or secondary perfluoroalkyl ligands by photoinitiated reactions between AuI organometallic complexes and iodoperfluoroalkanes. Complexes of the types LAuRF (L=PPh3 or N,N-bis(2,6-diisopropylphenyl)imidazol-2-ylidene; RF=n-C4F9, n-C6F13, i-C3F7, c-C6F11) and [Au(RF)(Ar)I(PPh3)] (Ar=2,4,6-trimethylphenyl) have been isolated and characterized. Alkynes RFC≡CR were formed by reaction of Ph3PAuC≡CR (R=Ph, nHex) with IRF (RF=n-C4F9, i-C3F7). According to the evidences obtained, this transformation undergoes through a photoinitiated radical mechanism. AuIII complexes [Au(n-C4F9)(X)(Y)L] (X=Y=Cl, Br, I, Me; X=Me, Y=I) have been prepared or in situ generated, and their thermal or photochemical decomposition reactions have been studied.  相似文献   

5.
Aliphatic perfluorinated carboxylic esters have been prepared by two methods; (i) the reaction of the potassium salt of perfluoro 3-ethyl pent-3-ol, KOC(C2F5)3, with perfluoro acid chlorides RfCOCl, to yield perfluorinated esters of composition RfCOOC(C2F5)3, and (ii) the reaction of carbonyl chloride or thionyl chloride with a mixture of the potassium salt KOC(C2F5)3 and perfluoro acid salts of the general formula KOCORf in a polar solvent. The product ester has the composition RfCOOC(C2F5)3, and in this instance carbon dioxide or sulphur dioxide is liberated during the reaction. A qualitative study of the thermal decomposition of a perfluoro ester has been made.A tertiary perfluoro carbonate of composition [(C2F5)2CF3CO]2CO has been prepared by the reaction of phosgene with the potassium salt KOC(C2F5)2CF3 in a polar solvent. The intermediate acid chloride (C2F5)2CF3COCOCl can be isolated.  相似文献   

6.
The suitability of n-hexane and n-octane as reactant gases in chemical ionization mass spectrometry has been investigated. The mass spectra of these substances have been investigated as a function of pressure up to 2·4 Torr for n-hexane and 1·7 Torr for n-octane. The major ion present in n-hexane at 0·8 Torr is [C6H13]+ (m/e 85) with a relative intensity of 0·65. In n-octane at 0·8 Torr the major ions are [C8H17]+ (m/e 113), [C6H13]+ (m/e 85) and [C5H11]+ (m/e 71). The relative intensities of these ions are 0·38, 0·12 and 0·19, respectively. These alkyl ions in both n-hexane and n-octane are thought to have tertiary structures. Rate constants for the rates of reaction of the primary ions in the two compounds have been determined. The n-hexane chemical ionization spectra of 26 compounds were determined. The spectra of polar compounds are dominated by proton transfer, whereas those of nonpolar compounds exhibit proton transfer and in addition often surprisingly large amounts of electron transfer. The n-octane chemical ionization spectra of 15 compounds were determined and the spectra in general are quite similar to those obtained with n-hexane. n-Hexane and n-octane can be used as reagents in analytical chemical ionization mass spectrometry, but except in certain specialized uses they would probably have no advantage over i-butane.  相似文献   

7.
The electrochemical fluorination of 2-methyloxane, oxepane, 2-chloromethyloxane and 2-chloromethyloxolane has been carried out. The corresponding perfluoro(2-methyloxane) and perrfluorooxepane were obtained in fair yields from the first two compounds, but from the later two, the corresponding chlorine-containing perfluorocyclic ethers, i.e. perfluoro(2-chloromethyloxane) and perfluoro(2-chloromethyloxolane), were obtained only in small yields, respectively. These new compounds have been characterized by elemental analysis, and infrared, mass and 19F nmr spectra.  相似文献   

8.
Perfluoroalkylation of a higher fullerene mixture with CF3I or C2F5I, followed by HPLC separation of CF3 and C2F5 derivatives, resulted in the isolation of several C84(RF)n (n=12, 16) compounds. Single‐crystal X‐ray crystallography with the use of synchrotron radiation allowed structure elucidation of eight C84(RF)n compounds containing six different C84 cages (the number of the C84 isomer is given in parentheses): C84 (23)(C2F5)12 ( I ), C84 (22)(CF3)16 ( II ), C84 (22)(C2F5)12 ( III ), C84 (11)(C2F5)12 ( IV ), C84 (16)(C2F5)12 ( V ), C84 (4)(CF3)12 ( VI with toluene and VII with hexane as solvate molecules), and C84 (18)(C2F5)12 ( VIII ). Whereas some connectivity patterns of C84 isomers (22, 23, 11) had previously been unambiguously confirmed by different methods, derivatives of C84 isomers numbers 4, 16, and 18 have been investigated crystallographically for the first time, thus providing direct proof of the connectivity patterns of rare C84 isomers. General aspects of the addition of RF groups to C84 cages are discussed in terms of the preferred positions in the pentagons under the formation of chains, pairs, and isolated RF groups.  相似文献   

9.
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   

10.
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   

11.
The 70 e V-electron impact mass spectra of the C7–C10 n-alkynes have been determined as well as the metastable ion spectra of the molecular ions and the [CS2]+ and [N2O]+ charge exchange mass spectra of the C7-C9 n-alkynes. The metastable ion mass spectra provide only a limited opportunity to distinguish between isomers; however, the 70-eV EI mass spectra of isomeric compounds permit a ready distinction between isomers. The [CS2]+ charge exchange mass spectra of isomeric compounds also show substantial differences. The [N2O]+ charge exchange mass spectra do not show the enhancement of β-fission fragments observed in field ionization experiments, despite representing ions of similar internal energy, and it is concluded that field dissociation is responsible for the β-fission fragments in the field ionization experiments.  相似文献   

12.
Two kinds of fluoroalkyl end-capped vinyltrimethoxysilane oligomer [RF-(VM) n -RF] silica nanocomposites containing biphenylene units were prepared by the sol-gel reactions of the corresponding oligomer with biphenylene-bridged ethoxysilanes or 4,4′-biphenol under alkaline conditions, respectively. One is the fluorinated oligomer/silica nanocomposites containing biphenylene units [RF-(VM-SiO2) n –RF/Ar-SiO 2 ], of whose biphenylene units were incorporated into nanocomposite cores through the siloxane bondings, and the other is the fluorinated oligomer/silica nanocomposites containing biphenylene units [RF-(VM-SiO2) n –RF/Biphenol], of whose biphenylene units were directly encapsulated into nanocomposite cores through the sol–gel process. Interestingly, the shape of RF-(VM-SiO2) n –RF/Ar-SiO 2 nanocomposites is morphologically controlled cubic particles; although the shape of RF-(VM-SiO2) n –RF/Biphenol nanocomposites is spherically fine particles. Thermogravimetric analyses 2H magic-angle spinning nuclear magnetic resonance, Ultraviolet visible, and fluorescent spectra showed that biphenylene units in RF-(VM-SiO2) n –RF/Ar-SiO 2 nanocomposites have a flammable characteristic after calcinations at 800 °C; in contrast, biphenylene units in RF-(VM-SiO2) n –RF/Biphenol nanocomposites have a nonflammable characteristic even after calcination at 800 °C. X-ray photoelectron spectroscopy analyses of these two kinds of fluorinated nanocomposites showed that nonflammable characteristic toward biphenylene units in the silica gel matrices is due to the formation of ammonium hexafluorosilicate during the sol–gel process.  相似文献   

13.
Di‐ and triorganotin(IV) carboxylates, RnSn(OCOC(R2)=CHR1)4–n (n = 2 and 3; R = Me, Et, n‐Bu, Ph; R1 = 3‐CH3O‐4‐OHC6H3, R2 = C6H5) were prepared by reacting the corresponding organotin(IV) chloride with the silver salt of the (E)‐3‐(4‐hydroxy‐3‐methoxyphenyl)‐2‐phenylpropenoic acid. The title compounds were investigated and characterized by elemental analysis, infrared (FT‐IR), multinuclear (1H, 13C, 119Sn) NMR, and mass spectrometry, and possible structures were proposed. The complexes and ligand acid ( HL ) have been evaluated in vitro against various bacteria and fungi. The results noticed during the biocidal activity screenings proved their in vitro biological potential. They were also tested for cytotoxicity.  相似文献   

14.
Some new quaternary compounds of the type BaLnMQ3 (Ln = rare earth or Sc; M = Cu, Ag; Q = S, Se) have been synthesized by the reaction of the constituent binary chalcogenides and elements at 1000°C. The crystal structures of two of these compounds have been determined by single-crystal X-ray diffraction techniques and are isostructural. Crystal data: BaErCuS3—space group D172hCmcm, M= 464.32, Z = 4 , a = 3.987(1), b = 13.377(3), c = 10.101(2) Å (T = 115 K), V = 538.7(4) Å3, Rw (F2) = 0.095 for 848 observations and 24 variables, R(F) = 0.037 for 840 observations having F20 > 2σ (F20); BaYAgSe—space group D172hCmcm, M = 571.0, Z = 4, a = 4.239(1), b = 14.030(2), c = 10.636(2) Å (T = 115 K), V = 632.6(2) Å3, Rw (F2) = 0.057 for 645 observations and 24 variables, R(F) = 0.023 for 595 observations having F20 > 2σ(F20). These two compounds adopt the layered KZrCuS3 structure type. The layers, which are separated by Ba2+ ions, consist of edge-sharing octahedral chains and corner-sharing tetrahedral chains. The other compounds synthesized crystallize either with this same structure or with that of β-BaLaCuSe3, a slightly distorted variation, which is isostructural with Eu2CuS3. The diffuse reflective UV-visible spectra of several of these compounds have been measured. From magnetic susceptibility measurements, both BaNdCuS3 and BaGdCuS3 show Curie-Weiss behavior, whereas BaCeCuS3 and BaCeCuSe3 show in addition temperature-independent paramagnetism.  相似文献   

15.
The perfluorinated dihydrophenazine derivative (perfluoro‐5,10‐bis(perfluorophenyl)‐5,10‐dihydrophenazine) (“phenazineF”) can be easily transformed to a stable and weighable radical cation salt by deelectronation (i.e. oxidation) with Ag[Al(ORF)4]/ Br2 mixtures (RF=C(CF3)3). As an innocent deelectronator it has a strong and fully reversible half‐wave potential versus Fc+/Fc in the coordinating solvent MeCN (E°′=1.21 V), but also in almost non‐coordinating oDFB (=1,2‐F2C6H4; E°′=1.29 V). It allows for the deelectronation of [FeIIICp*2]+ to [FeIV(CO)Cp*2]2+ and [FeIV(CN‐tBu)Cp*2]2+ in common laboratory solvents and is compatible with good σ‐donor ligands, such as L=trispyrazolylmethane, to generate novel [M(L)x]n+ complex salts from the respective elemental metals.  相似文献   

16.
A new fluorinated polystyrene bearing a p-sulbstiuted perfluoro[1-(2-fluorosulfonylethoxy)]ethyl group was synthesized via one-electron oxidation of polystyrene by perfluoro[2-(2-fluorosulfonylethoxy)]propionyl peroxide at different peroxide to polystyrene molar ratios.The yield of perfluoroalkylation decreases with the increase of the reactant molar ratio.The modified polymer has been characterized by various techniques:the ring pefluoro[1-(2-fluorosulfonylethoxy)]ethylation has been proved by FT-IR and ^19FNMR;the X-ray photoelectron spectra(XPS) show the maximum binding energy of F18,O18,C18(two kinds of carbon atoms,namely C-H and C-F)and S2p,respectively; desulfonylation of the fluorinated polystyrene appearing at 217℃ has been found by its thermogravimetric analysis (TGA).The determinations of contact angle,refractive index and glass transition temperature of the modified polymer have disclosed that when the contact angle increases with the increase of the molar ratio,the refractive index and glass transition temperature decrease.The polydispersity values indicate that the degradation of the polymer chains did not occur during the reaction.  相似文献   

17.
Non fluorinated organo silver compounds are thermally unstable. In contrast fluorinated organo silver compounds are thermally more stable, the stability increasing with perfluoro aromatic counterparts rather than perfluoro aliphatic systems.The synthesis of pentafluorophenyl silver can be done by several methods:
Similar results are obtained using complexes of silver pentafluorobenzoate with α, α′-Dipyridyl or o-phenanthroline as starting compounds.The C6F-Ag-compounds react as C6F5-transferring systems. Their structur seems to consist of clusters, the highest mass number found corresponding to [Ag4(C6F5)3]+. On thermal degradation [Ag2C6F5]n seems to be formed.Increased thermal stability is shown by Paratetrafluorophenylene disilver, which is formed by decarboxylation of silver tetrafluoro terephthalate. Although insoluble in organic solvents it can be reacted in suspension yielding 1,4 derivatives of tetrafluorobenzene. All complexes of silver tetrafluoro phthalate are degraded during decarboxylation with the formation of Para-tetrafluorophenylene disilver.  相似文献   

18.
N-Acetylcysteine and nine N-acetylcysteine conjugates of synthetic origin were characterized by positive- and negative-ion plasma desorption mass Spectrometry. For sample preparation the electrospray technique and the nitrocellulose spin deposition technique were applied. The fragmentation of these compounds, which are best seen as S-substituted desaminoglycylcysteine dipeptides, shows a similar behaviour to that of linear peptides. In the positive-ion mass spectra intense protonated molecular ion peaks are observed. In addition, several sequence-specific fragment ions (A+, B+, [Y + 2H]+, Z+), immonium ions (I+) and a diagnostic fragment ion for mercap-turic acids (RM+) are detected. The negative-ion mass spectra exhibit deprotonated molecular ions and in contrast only one fragment ion corresponding to side-chain specific cleavage ([RXS]?) representing the xenobiotic moiety. In the case of a low alkali metal concentration on the target, cluster molecular ions of the [nM + H]+ or [nM - H]? ion type (n = 1-3) are observed. The analysis of an equimolar mixture of eight N-acetylcysteine conjugates shows different quasi-molecular ion yields for the positive- and negative-ion spectra.  相似文献   

19.
The high-resolution207Pb magnetic resonance spectra ofR 4–n PbX n (R=Methyl, Ethyl;X=h1-Cyclopentadienyl, Chloride;n=1, 2) have been studied at 16.72Mc. The207Pb- ·· -1H spin-spin coupling constants for the molecules described have been obtained by analysis of the first order NMR-patterns as AxByM and AxByCzM respectively. The experimental spectra have been verified by a computer simulation. The chemical shifts and coupling constants of the lead organyls investigated show similar dependences on moleculare structure as well as number and species of the substituents like analogous organotin compounds.
  相似文献   

20.
Thermal decarbonylation of the acyl compounds [Mn(CO)5(CORF)] (RF=CF3, CHF2, CH2CF3, CF2CH3) yielded the corresponding alkyl derivatives [Mn(CO)5(RF)], some of which have not been previously reported. The compounds were fully characterized by analytical and spectroscopic methods and by several single-crystal X-ray diffraction studies. The solution-phase IR characterization in the CO stretching region, with the assistance of DFT calculations, has allowed the assignment of several weak bands to vibrations of the [Mn(12CO)4(eq-13CO)(RF)] and [Mn(12CO)4(ax-13CO)(RF)] isotopomers and a ranking of the RF donor power in the order CF3<CHF2<CH2CF3≈CF2CH3. The homolytic Mn−RF bond cleavage in [Mn(CO)5(RF)] at various temperatures under saturation conditions with trapping of the generated RF radicals by excess tris(trimethylsilyl)silane yielded activation parameters ΔH and ΔS that are believed to represent close estimates of the homolytic bond dissociation thermodynamic parameters. These values are in close agreement with those calculated in a recent DFT study (J. Organomet. Chem. 2018 , 864, 12–18). The ability of these complexes to undergo homolytic Mn−RF bond cleavage was further demonstrated by the observation that [Mn(CO)5(CF3)] (the compound with the strongest Mn−RF bond) initiated the radical polymerization of vinylidene fluoride (CH2=CF2) to produce poly(vinylidene fluoride) in good yields by either thermal (100 °C) or photochemical (UV or visible light) activation.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号