排序方式: 共有23条查询结果,搜索用时 15 毫秒
1.
2.
3.
The relative fluoride donor ability: C6F5BrF2 > C6F5IF2 > C6F5IF4 was outlined from reactions with Lewis acids of graduated strength in different solvents. Fluoride abstraction from C6F5HalF2 with BF3·NCCH3 in acetonitrile (donor solvent) led to [C6F5HalF·(NCCH3)n][BF4]. The attempted generation of [C6F5BrF]+ from C6F5BrF2 and anhydrous HF or BF3 in weakly coordinating SO2ClF gave C6F5Br besides bromoperfluorocycloalkenes C6BrF7 and 1-BrC6F9. In reactions of C6F5IF2 with SbF5 in SO2ClF the primary observed intermediate (19F NMR, below 0 °C) was the 4-iodo-1,1,2,3,5,6-hexafluorobenzenium cation, which converted into C6F5I and 1-IC6F9 at 20 °C. The reaction of C6F5IF4 with SbF5 in SO2ClF below −20 °C gave the cation [C6F5IF3]+ which decomposed at 20 °C to C6F5I, 1-iodoperfluorocyclohexene, and iodoperfluorocyclohexane. Principally, the related perfluoroalkyl compound C6F13IF4 showed a different type of products in the fast reaction with AsF5 in CCl3F (−60 °C) which resulted in C6F14. Intermediate and final products of C6F5HalFn−1 (n = 3, 5) with Lewis acids were characterized by NMR in solution. Stable solid products were isolated and analytically characterized. 相似文献
4.
The dependence of the 129Xe NMR chemical shift value of XeF2 on temperature and concentration was determined in a variety of prototypic media: in acidic (anhydrous HF, aHF), nonprotic but polar (dichloromethane), and basic (CD3CN-EtCN, 1:3 v/v) solvents. The 129Xe NMR spectra of a representative series of organoxenon(II) salts [RXe][Y] (R = C6F5, heptafluoro-1,4-cyclohexadien-1-yl (cyclo-1,4-C6F7), pentafluoro-1,4-cyclohexadien-3-on-1-yl (cyclo-3-O-1,4-C6F5), CF2=C(CF3), (CF3)2CFC[triple bond]C, C4H9C[triple bond]C; Y = BF4, AsF6) in aHF showed, compared with XeF2-aHF, a quantitatively less distinct but qualitatively related dependence of delta(129Xe) vs temperature. The dependence of their delta(129Xe) values on concentration in aHF is negligible. An explanation for the different behavior of [RXe][Y] and XeF2 is offered. 相似文献
5.
A series of previously unknown asymmetrical fluorinated bis(aryl)bromonium, alkenyl(aryl)bromonium, and alkynyl(aryl)bromonium salts was prepared by reactions of C6F5BrF2 or 4-CF3C6H4BrF2 with aryl group transfer reagents Ar′SiF3 (Ar′ = C6F5, 4-FC6H4, C6H5) or perfluoroorganyl group transfer reagents RF′BF2 (RF = C6F5, trans-CF3CFCF, C3F7C≡C) preferentially in weakly coordinating solvents (CCl3F, CCl2FCClF2, CH2Cl2, CF3CH2CHF2 (PFP), CF3CH2CF2CH3 (PFB)). The presence of the base MeCN and the influence of the adducts RF′BF2·NCMe (RF = C6F5, CF3C≡C) on reactions aside to bromonium salt formation are discussed. Reactions of C6F5BrF2 with AlkF′BF2 in PFP gave mainly C6F5Br and AlkF′F (AlkF′ = C6F13, C6F13CH2CH2), presumably, deriving from the unstable salts [C6F5(AlkF′)Br]Y (Y = [AlkF′BF3]−). Prototypical reactivities of selected bromonium salts were investigated with the nucleophile I-and the electrophile H+. [4-CF3C6H4(C6F5)Br][BF4] showed the conversion into 4-CF3C6H4Br and C6F5I when reacted with [Bu4N]I in MeCN. Perfluoroalkynylbromonium salts [CnF2n+1C≡C(RF)Br][BF4] slowly added HF when dissolved in aHF and formed [Z-CnF2n+1CFCH(RF)Br][BF4]. 相似文献
6.
A promising approach to the unknown type of [Ar′(Ar)IF2]X salts is offered. x-FC6H4IF4 (x=2, 3, 4) reacts with C6F5BF2 in CH2Cl2 and forms [x-FC6H4(C6F5)IF2][BF4] salts in good yields. For [4-FC6H4(C6F5)IF2][BF4] the fluoro-oxidizer property is shown in reactions with weakly reducing agents like E(C6F5)3 (E=P, As, Sb, Bi) and ArI (Ar=4-FC6H4, C6F5). The fluorine/aryl substitution method is also applied to the synthesis of [(4-FC6H4)2IF2][BF4], an example with two identical aryl groups in the difluoroiodonium(V) moiety. 相似文献
7.
The salt [CF3C[triple bond]CXe] [BF4] was prepared as neat compound by the reaction of the hitherto unknown alkynyldifluoroborane CF3C[triple bond]CBF2 with XeF2 in 1,1,1,3,3-pentafluoropropane (PFP) at -45 degrees C in 59% yield. [CF3C[triple bond]CXe] [BF4] was unambiguously characterised by multinuclear NMR spectroscopy in anhydrous HF (aHF) solution. 相似文献
8.
The electrophilic oxygenation of pentafluorophenyl iodo compounds C6F5IFn with iodine in different valencies (n = 0, 2, 4) using XeF2-H2O in HF allowed access to new organoiodine(V) compounds, namely isomeric oxopentafluorocyclohexadien-1-yliodine tetrafluorides, C6(O)F5IF4. 相似文献
9.
The nucleophilic hydrodefluorination of C3F7OCFCF2 with the complex hydrides Li[AlH4], Li[BH4] or Na[BH4] proceeded non-stereoselectively and was accompanied by the formation of either cis- and trans-C3F7OCHCFH and/or C3F7OCHFCF2H. The reaction of C3F7OCFCF2 with PBu3 followed by treatment with BF3·OMe2 or BF3·OEt2 yielded [C3F7OCFCFPBu3] [BF4] (cis and trans) and, probably, [trans-Bu3PCFCFPBu3] [BF4]2. The hydrolysis of the latter with pure water proceeded quickly while the former isomeric mixture formed the isomeric olefins C3F7OCFCFH slowly. The usage of aqueous NaOH instead of water produced mainly trans-CHFCHF. The metallation of C3F7OCFCFH (cis:trans=45:55) to C3F7OCFCFLi and its subsequent reaction with B(OMe)3 and K[HF2] gave the salt K[C3F7OCFCFBF3] in a different cis to trans ratio (25:75) with satisfactory yield. 相似文献
10.
Hermann-Josef Frohn Nicolay Yu. AdoninVadim V. Bardin Vladimir F. Starichenko 《Journal of fluorine chemistry》2002,117(2):115-120
For the first time (polyfluoroorgano)trifluoroborate salts, namely K[C6F5BF3], K[C6HF4BF3] (all three isomers), K[3,4,5-C6H2F3BF3], and K[CF2CFBF3] were principally applied as reagents to Pd-catalysed cross-coupling reactions. A series of polyfluorinated biphenyls C6H5−nFn-C6H4X-4′ were obtained from K[C6H5−nFnBF3] and the substrates [4-XC6H4N2][BF4] in the presence of Pd catalysts. The influence of the number and the position of the fluorine atoms in the (polyfluorophenyl)trifluoroborate salts on the reactivity in the coupling reaction was elucidated. In addition to (polyfluorophenyl)trifluoroborate salts, the cross-coupling was expanded to a first example of a perfluoroalkenyl reagent. K[CF2CFBF3] reacted with [4-FC6H4N2][BF4] and formed CF2CF-C6H4F-4. 相似文献