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1.
The products of Cl atom and OH radical initiated oxidation of CF3CFCH2 were studied in 700 Torr of N2/O2 diluent at 296 ± 1 K. The reactions of Cl atoms and OH radicals with CF3CFCH2 proceed via electrophilic addition to the double bond. The reaction with chlorine atoms proceeds 56 ± 5% via addition to the central carbon. The chlorine atom initiated oxidation of CF3CFCH2 gives CF3C(O)F in a molar yield which is indistinguishable from 100% and independent of [O2], and HC(O)Cl in a molar yield which increased from 30% to 59% as [O2] was increased from 3 to 700 Torr. The OH radical initiated oxidation of CF3CFCH2 gives CF3C(O)F as major product in a yield of 91 ± 6%. The results are discussed with respect to the atmospheric chemistry and environmental impact of CF3CFCH2.  相似文献   

2.
The interaction of tris(trimethylsilyl) phosphite (TMSO)3P and E-trifluoromethyl-β-alkoxyenones CF3C(O)CHCHOEt and CF3C(O)CHC(OMe)Me yielded mixtures of E-1,2- and Z-1,4-adducts, CF3C(OTMS)[P(O)(OTMS)2]CCH(OAlk)R 2 and CF3(OTMS)CCHCR(OAlk)[P(O)(OTMS)2] 3 where R and Alk = H and Me, or both Me. Conversion of these 1,2-adducts to 1,4-isomers was effected by increased temperature or by exposure to more tris(trimethylsilyl) phosphite. Acid hydrolysis of 2b (R and Alk = Me) gave ketophosphonic acid CF3C(OH)[P(O)(OH)2]CH2COMe in 88% yield, whereas hydrolysis of 2a (R = H and Alk = Et) with KOH in methanol gave CF3C(OH)[P(O)(OK)2]CHCHOEt in 37% yield. Acid hydrolysis of 3a (R = H and Alk = Et) and 3b (R and Alk = Me) gave phosphonic acid CF3C(OH)2CHCHP(O)(OH)2 in 82% yield and trifluoromethylated 1,2λ5σ4-oxaphosphol-3-en.  相似文献   

3.
Trimethylamine‐bis(trifluoromethyl)boranes R(CF3)2B · NMe3 (R = cis/trans‐CF3CF=CF ( 1/2 ), HC≡C ( 3 ), H2C=CH ( 4 ), C2H5 ( 5 ), C6H5CH2 ( 6 ), C6F5 ( 7 ), C6H5 ( 8 )) react with NEt3 × 3 HF depending on the nature of R at 155–200 °C under replacement of the trimethylamine ligand to form the corresponding fluoro‐bis(trifluoromethyl)borates [R(CF3)2BF] ( 1 a/2 a – 8 a ). The structures of 7 , K[C6H5CH2(CF3)2BF] ( K‐6 a ), and K[C6H5(CF3)2BF] ( K‐8 a ) have been investigated by single‐crystal X‐ray diffraction. In 7 the CF3 groups make short repulsive contacts with NMe3 and C6F5 entities – the B–CF3 bonds being unusually long. The B–F bond lengths of K‐6 a and K‐8 a (1.446(3) and 1.452(2) Å, respectively) are long for a fluoroborate.  相似文献   

4.
A representative series of diphosphine monophosphonium salts [1‐Ph2P(C10H6)‐8‐PRPh2]+X ( 2 b : R = H, X = CF3SO3; 4 : R = Me, X = CF3SO3; 5 : R = C6H5CH2 = Bn, X = Br) has been prepared by treatment of 1,8‐bis(diphenylphosphino)naphthalene (dppn, 1 ) with stoichiometric amounts of HSO3CF3 or CH3SO3CF3 in CH2Cl2 at +20 °C and with C6H5CH2Br in toluene at +80 °C. Their X‐ray crystal structures show that there is no evidence for dative P → P+ interactions. Instead, steric repulsion deflects the substituent groups to opposite faces of the naphthalene plane [splay angles: +11.4° ( 2 b ), +13.6° ( 4 ); +16.7° ( 5 )]. In solution 2 b , 4 , and 5 were dynamic according to 31P, 13C, and 1H NMR spectroscopy. The fluxionality of 2 b involves rapid intramolecular proton exchange between the two phosphorus atoms, which slows down at low temperature, whereas the dynamic behaviour of 4 and 5 is interpreted in terms of hindered rotation of the bulky RPh2P+ groups (R = Me or Bn) about the P–C(naphthyl) bond. Treatment of 1,8‐bis(diphenylphosphoryl)naphthalene (dppnO2, 6 ) with HSO3CF3 gave the protonated bis(phosphine oxide), as the triflate salt, dppnO2H+ CF3SO3 ( 7 ). The X‐ray structure analysis of 7 revealed a highly strained molecule (P1…P2 365.5 pm) in which the P=O bonds point to the same face of the naphthalene plane to accommodate the proton. All isolated compounds were characterised by a combination of 31P, 1H, and 13C NMR spectroscopy, IR spectroscopy ( 7 ), mass spectrometry and elemental analysis.  相似文献   

5.
A palladium‐catalyzed selective C? H bond trifluoroethylation of aryl iodides has been explored. The reaction allows for the efficient synthesis of a variety of ortho‐trifluoroethyl‐substituted styrenes. Preliminary mechanistic studies indicate that the reaction might involve a key PdIV intermediate, which is generated through the rate‐determining oxidative addition of CF3CH2I to a palladacycle; the bulky nature of CF3CH2I influences the reactivity. Reductive elimination from the PdIV complex then leads to the formation of the aryl–CH2CF3 bond.  相似文献   

6.
A palladium‐catalyzed selective C H bond trifluoroethylation of aryl iodides has been explored. The reaction allows for the efficient synthesis of a variety of ortho‐trifluoroethyl‐substituted styrenes. Preliminary mechanistic studies indicate that the reaction might involve a key PdIV intermediate, which is generated through the rate‐determining oxidative addition of CF3CH2I to a palladacycle; the bulky nature of CF3CH2I influences the reactivity. Reductive elimination from the PdIV complex then leads to the formation of the aryl–CH2CF3 bond.  相似文献   

7.
The first photoelectron band of difluorocarbene CF2, has been studied by threshold photoelectron (TPE) spectroscopy. CF2 was prepared by microwave discharge of a flowing mixture of hexafluoropropene, C3F6, and argon. A vibrationally resolved band was observed in which at least twenty‐two components were observed. In the first PE band of CF2, the adiabatic ionization energy differs significantly from the vertical ionization energy because, for the ionization CF2+ (X?2A1)+e? ← CF2 (X?1A1), there is an increase in the FCF bond angle (by ≈20°) and a decrease in the C? F bond length (by ≈0.7 Å). The adiabatic component was not observed in the experimental TPE spectrum. However, on comparing this spectrum with an ab initio/Franck–Condon simulation of this band, using results from high‐level ab initio calculations, the structure associated with the vibrational components could be assigned. This led to alignment of the experimental TPE spectrum and the computed Franck–Condon envelope, and a determination of the first adiabatic ionization energy of CF2 as (11.362±0.005) eV. From the assignment of the vibrational structure, values were obtained for the harmonic and fundamental frequencies of the symmetric stretching mode (ν1′) and symmetric bending mode (ν2′) in CF2+ (X?2A1).  相似文献   

8.
3-Aminopropanol reacts with aryl(or aralkyl or alkyl)isothiocyanates R? N?C?S to yield the corresponding thio-ureas R? NH? CS? NH? (CH2)3OH which, refluxed with hydrochloric acid, are cyclized by elimination of water. The cyclization products are identical with the hydrothiazines resulting by elimination of sulfate or phosphate from the sulfuric or phosphoric monoesters of these thio-ureas. The resulting hydrothiazines are either 2-(R-imino)-tetrahydro-m-thiazines (I) or 2-(R-amino)-dihydro-Δ2-m-thiazines (II). Their structure has been established by comparison of their spectra with those of model compounds in one of which the C?N double bond is certainly endocyclic (2-methyl-dihydro-Δ2-m-thiazine), the other presenting an exocyclic C?N double bond (3-methyl-2-phenylimino-tetrahydro-m-thiazine). When R is an aryl group, the C?N double bond is exocyclic (structure I with >C?N? Ar), and one may presume that this structure is stabilized by resonance. When R is an aralkyl or an alkyl group, the C?N double bond is endocyclic (structure II). The nmr spectra were taken with three types of solvent: CDCl3 or CCl4; (CD3)2SO; CF3COOH. In CF3COOH solution the benzylic protons of the hydrothiazine with R = pF? C6H4CH2? couple with NH (J=5,5cps) which confirms the endocyclic position of the C?N double bond in this case.  相似文献   

9.
The kinetic properties of the hydrogen abstraction reactions of CF3CH2F + F → CF3CHF + HF (R1) and CF3CH2Cl + F → CF3CHCl + HF (R2) have been studied by dual-level direct dynamics method. Optimized geometries and frequencies of all the stationary points and extra points along the minimum-energy path (MEP) were obtained at the B3LYP/6-311 + G(2d,2p) level. Two complexes with energies less than that of the reactants were located in the reactant side of each reaction. The energy profiles were further refined with the interpolated single-point energies (ISPE) method at the G3(MP2) level of theory. Using canonical variational transition state theory (CVT) with the small-curvature tunneling correction (SCT) method, the rate constants were evaluated over a wide temperature range of 200–2,000 K. Our calculations have shown that C–H bond activity decreases when one hydrogen atom of CF3CH3 is substituted by a fluorine atom, than when substituted with a chlorine atom. This is in good agreement with the experimental results.  相似文献   

10.
Bis‐trimethylamine‐ethynyl‐di‐bis(trifluoromethyl)borane [Me3N(CF3)2BCCB(CF3)2NMe3] ( 1 ) has been prepared from trimethylamine‐ethynyl‐bis(trifluoromethyl)borane, [HCCB(CF3)2NMe3], and dimethylamino‐bis(trifluoromethyl)borane, (CF3)2BNMe2. The structure of 1 has been determined by x‐ray crystallography. In the solid state the molecule possesses crystallographic Ci symmetry. The acetylenic attachment to the boron atom is characterized by a short B–C bond length of 1.565(4) Å and an essentially linear B–C–C′ bond angle of 178.1(4)°.  相似文献   

11.
12.
In contrast to RFSO3CH2R(1)(R=hydrogen, alkyl and perfluoroalkyl) and RFSO3CF2RF′ (2), the reactions of difluoromethyl perfluoroalkanesulfonates RFSO3CF2H (3) With nucleophiles are more complicated. Halide inos, X? (X = F, Cl, I) and ethanol only attack the alkoxyl carbon atom, cleaving the C? O bond to give HCF2X (4) and HCF2OEt (5) respectively. Other reagents such as RCO2? (R=CH3, CF3), C6H5S? etc. can either attack the carbon or sulfur atom of 3 to give the corresponding products of C? O and S? O bond cleavages. More basic nucleophiles RO? (R = C6H5, Et) mainly abstract the proton of the HCF2 moiety to produce difluorocarbene. Ether and benzene, which can be alkylated by methyl perfluoroalkanesulfonate, do not react with 3 under similar conditions. The reaction rate of 3 with KF is much slower than that of 1 (R = H). All these data seem to indicate that the shielding effect caused by the two fluorine atoms on the methyl carbon in 3 prevents to some extent the nucleophilic attack on this carbon, but not so completely as in 2 due to the presence of a hydrogen atom.  相似文献   

13.
The diiron vinyliminium complexes [Fe2{μ-η13-C(R′)C(H)CN(Me)(R)}(μ-CO)(CO)(Cp)2][SO3CF3] (R=Me, R′ = SiMe3 (1a); R = Me, R′ = CH2OH (1b); R = CH2Ph, R′ = Tol (1c), Tol = 4-MeC6H4; R = CH2Ph, R′ = COOMe (1d); R = CH2Ph, R′ = SiMe3 (1e)) undergo regio- and stereo-selective addition by cyanide ion (from ), affording the corresponding bridging cyano-functionalized allylidene compounds [Fe2{μ-η13-C(R′)C(H)C(CN)N(Me)(R)}(μ-CO)(CO)(Cp)2] (3a-e), in good yields. Similarly, the diiron vinyliminium complexes [Fe2{μ-η13-C(R′)C(R′)CN(Me)(R)}(μ-CO)(CO)(Cp)2][SO3CF3] (R = R′ = Me (2a); R = Me, R′ = Ph (2b); R = CH2Ph, R′ = Me (2c); R = CH2Ph, R′ = COOMe (2d)) react with cyanide and yield [Fe2{μ-η13-C(R′)C(R′)C(CN)N(Me)(R)}(μ-CO)(CO)(Cp)2] (9a-d). The reactions of the vinyliminium complex [Fe2{μ-η13-C(Tol)CHCN(Me)(4-C6H4CF3)}(μ-CO)(CO)(Cp)2][SO3CF3] (4) with NaBH4 and afford the allylidene [Fe2{μ-C(Tol)C(H)C(H)N(Me)(C6H4CF3)}(μ-CO)(CO)(Cp)2] (5) and the cyanoallylidene [Fe2{μ-C(Tol)C(H)C(CN)N(Me)(C6H4CF3)}(μ-CO)(CO)(Cp)2] (6), respectively. Analogously, the diruthenium vinyliminium complex [Ru2{μ-η13-C(SiMe3)CHCN(Me)(CH2Ph)}(μ-CO)(CO)(Cp)2][SO3CF3] (7) reacts with to give [Ru2{μ-η13-C(SiMe3)CHC(CN)N(Me)(CH2Ph)}(μ-CO)(CO)(Cp)2] (8).Finally, cyanide addition to [Fe2{μ-η13-C(COOMe)C(COOMe)CN(Me)(Xyl)}(μ-CO)(CO)(Cp)2][SO3CF3] (2e) (Xyl = 2,6-Me2C6H3), yields the cyano-functionalized bis-alkylidene complex [Fe2{μ-η12-C(COOMe)C(COOMe)(CN)CN(Me)(Xyl)}(μ-CO)(CO)(Cp)2] (10). The molecular structures of 3a and 9a have been elucidated by X-ray diffraction.  相似文献   

14.
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   

15.
Pentacarbonyl(arylphenylcarbene)tungsten complexes, (CO)5W[C(p-C6H4R)C6H5] (Ia, R = OCH3; Ib, R = CH3; Ic, R = H; Id, R = Br; Ie, R = CF3) react with dimethylcyanamide (II) via insertion of the CN group into the metalcarbene bond. The formation of pentacarbonyl[dimethylamino(imino)carbene]tungsten(0) (IIIa–IIIe) follows a second-order rate law: d[III]/dt = k[I][II]. Replacement of R = H by electron-withdrawing substituents (Br, CF3) results in an increase, by electron-donating groups (CH3, OCH3) in a decrease of the reaction rate. The rate constants correlate well with Hammett's σ-constants. The activation enthalpies ΔH are low (37.3–41.6 kJ mol?1), the activation entropies ΔS strongly negative (?119 to ?133 J mol?1 K?1). The results are discussed on the basis of an associative stepwise mechanism with a nucleophilic attack of the CN group of II at the carbene carbon in the first reaction step.  相似文献   

16.
13C, 17O and 73Ge NMR spectra of seven tetraalkoxygermanes have been investigated. 73Ge resonance signals in these compounds are more sensitive to structure variations than those of 29Si in isostructural alkoxysilanes. 17O and 13C NMR spectra of alkoxygermanes Me4-n Ge(OR)n (R = Et, Pr, Bu, i-Bu, s-Bu, CH2CHCH2, CH2CH2OMe, CH2CF3; n = 1–3) have been studied.It has been shown that the magnitude of (p—d)τ-bonding in the GeO bond is smaller than in the SiO bond, but variation in the extent of (p—d)τ-overlapping in alkozygermanes with different substituents is similar to that in the isostructural alkoxysilanes.  相似文献   

17.
For the first time, fluorinated oxathialones, polyfluoroalkylchlorothioformates, chlorocarbonylpolyfluoroalkylsulfenate esters, a chlorocarbonylhexafluoroisopropylidenimino sulfenate, and a 5-tri-fluoromethyl-2-oxo-1,3,4-oxathiazole were synthesized by reacting chlorocarbonylsulfenyl chloride with RfC(O)CH2C(O)R′ (Rf = CF3; R'= CF3, OC2H5), RfO-Li+ (Rf = CF3CH2, (CF3)2C=N-Li+ and CF3C(O)NH2. Perfluorosuccinic acid and mercury(II) trifluoroacetate with ClC(O)SCI gave their respective anhydrides.  相似文献   

18.
Trifluoromethylation of alkyl radicals is emerging as a powerful tool for C(sp3)–CF3 bond formations. Based on the hypothesis of CF3 group transfer from Cu(II)–CF3 to alkyl radicals, a number of trifluoromethylation reactions have been developed, including trifluoromethylation of alkyl halides, decarboxylative trifluoromethylation of aliphatic carboxylic acids, C(sp3)–H trifluoromethylation, amino‐ and carbo‐trifluoromethylation of alkenes, etc. Challenges in this intriguing field are also discussed.  相似文献   

19.
Abstract

The reactions of either PhPCl2 or PCl3 with (Me3Si)2NLi followed by H2C[dbnd]CHMgBr were used to prepare the new P-vinyl substituted [bis(trimethylsilyl)amino]phosphines, (Me3Si)2NP(R)CH[dbnd]CH2 [1: R=Ph, 2: CH[dbnd]CH2, 3: R=Me, and 4: R=N(SiMe3)2]. Oxidative bromination of phosphines 3–1 afforded the P-bromo-P-vinyl-N-(trimethylsilyl)phosphoranimines, Me3SiN[dbnd]P(CH[dbnd]CH2)(R)Br [5: R=Ph, 6: R=CH[dbnd]CH2, 7: R=Me], which, upon treatment with CF3CH2OH/Et3N, were subsequently converted to the P-trifluoroethoxy derivatives, Me3SiN[dbnd]P(CH[dbnd]CH2)(R)OCH2CF3 [8: R=Ph, 9: R=CH[dbnd]CH2, 10: R=Me]. Compounds 1–10, which are of interest as potential precursors to P-vinyl substituted poly(phosphazenes), were fully characterized by elemental analyses (except for the thermally unstable P-Br derivatives 5–7) and NMR spectroscopy (1H, 13C, and 31P) including complete analysis of the vinylic proton splitting patterns via HOM2DJ experiments.  相似文献   

20.
The R-C≡N…pyrrole (R=H, CH3, CH2F, CHF2, CF3, NH2, BH2, OH, F, CH2Cl, CHCl2, CCl3, Li, Na) complexes were considered as the simple sample for measure of hydrogen bonding strength. Density functional theory B3LYP/6-311 G^** level was applied to the optimization of geometries of complexes and monomers. Measure of hydrogen bonding strength based on geometrical and topological parameters, which were derived from the AIM theory, was analyzed. Additionally, natural bond orbital (NBO) analysis and frequency calculations were performed.From the computation results it was found that the electronic density at N-H bond critical points was also strictly correlated with the hydrogen bonding strength.  相似文献   

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