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1.
Novel oxazaborolidines B-C6F5 were synthesized by modified protocol from C6F5B(OMe)2 (in place of usual C6F5B(OH)2) and the corresponding amino alcohols, aiming to know the π-π stacking and electron-withdrawing effects of C6F5 group in asymmetric reduction of ketones. Although the results were not simply explained by the expected effects, significant difference was observed in the enantioselectivity between the catalysts with B-C6H5 and B-C6F5.  相似文献   

2.
A reaction of iodide [(η5-indenyl)IrI2]n (1) with thallium dicarbollide Tl[Tl(η-7,8-C2B9H11)] leads to (indenyl)iridacarborane (η5-indenyl)Ir(η-7,8-C2B9H11) (2) in 32% yield. The X-ray diffraction study showed that in the structure of 2, the five-membered rings C5 and C2B3 have a cisoid conformation, in which the bridgehead carbon atoms of the indenyl ligand are arranged opposite to the carborane cage carbon atoms. The DFT calculations showed that the Ir—indenyl bond in compound 2 is weaker than the Ir—Cp bond in the complex (η-7,8-C2B9H11)IrCp.  相似文献   

3.
The primary phosphines MesPH2 and tBuPH2 react with 9-iodo-m-carborane yielding B9-connected secondary carboranylphosphines 1,7-H2C2B10H9-9-PHR (R=2,4,6-Me3C6H2 (Mes; 1 a ), tBu ( 1 b )). Addition of tris(pentafluorophenyl)borane (BCF) to 1 a , b resulted in the zwitterionic compounds 1,7-H2C2B10H9-9-PHR(p-C6F4)BF(C6F5)2 ( 2 a , b ) through nucleophilic para substitution of a C6F5 ring followed by fluoride transfer to boron. Further reaction with Me2SiHCl prompted a H−F exchange yielding the zwitterionic compounds 1,7-H2C2B10H9-9-PHR(p-C6F4)BH(C6F5)2 ( 3 a , b ). The reaction of 2 a , b with one equivalent of R'MgBr (R’=Me, Ph) gave the extremely water-sensitive frustrated Lewis pairs 1,7-H2C2B10H9-9-PR(p-C6F4)B(C6F5)2 ( 4 a , b ). Hydrolysis of the B−C6F4 bond in 4 a , b gave the first tertiary B-carboranyl phosphines with three distinct substituents, 1,7-H2C2B10H9-9-PR(p-C6F4H) ( 5 a , b ). Deprotonation of the zwitterionic compounds 2 a , b and 3 a , b formed anionic phosphines [1,7-H2C2B10H9-9-PR(p-C6F4)BX(C6F5)2][DMSOH]+ (R=Mes, X=F ( 6 a ), R=tBu, X=F ( 6 b ); R=Mes, X=H ( 7 a ), R=tBu, X=H ( 7 b )). Reaction of 2 a , b with an excess of Grignard reagents resulted in the addition of R’ at the boron atom yielding the anions [1,7-H2C2B10H9-9-PR(p-C6F4)BR’(C6F5)2] (R=Mes, R’=Me ( 8 a ), R=tBu, R’=Me ( 8 b ); R=Mes, R’=Ph ( 9 a ), R=tBu, R’=Ph ( 9 b )) with [MgBr(Et2O)n]+ as counterion. The ability of the zwitterionic compounds 3 a , b to hydrogenate imines as well as the Brønsted acidity of 3 a were investigated.  相似文献   

4.
The reactions of the fluorobenzenes, C6F5H, o-C6H2F4, m-C6H2F4, p-C6H2F4, 1,3,5-C6F3H3, 1,2,4-C6F3H3, o-C6F2H4, m-C6F2H4, p-C6F2H4 and C6F5H with thiolate anion nucleophiles RS? (primarily MeS?), have been studied in ethylene glycol/pyridine mixtures as a solvent. Multiple replacement of fluorine atoms was observed in the more highly fluorinated compounds, but in all cases two aromatic fluorine atoms were not replaced. Difluorobenzene and fluorobenzene did not react. The product orientations have been deduced from their NMR spectra. The mass spectra of the isomeric products C6F2H3(SMe), C6F3H2(SMe) and C6F2H2(SMe)2 have been examined.  相似文献   

5.
Li[C2B10H10Me][MeN(CH2CH2NMe2)2], prepared by successive reaction of equimolar amounts of n-butyl-lithium and pentamethyldiethylenetriamine with 1-methyl-1,2-dicarba-closo-dodecarborane, C2B10H11Me, crystallises in the monoclinic space group P21/m, with a = 8.242(1), b = 13.522(1), c = 10.799(1) Å, β = 108.75(1)°, Z = 2. The crystal structure has been refined to R = 0.088 from 1128 unique diffractometer data with F > 6σ(F). The compound is unusual in that it contains a lithium atom terminally attached by a formally single LiC bond to the six-coordinate carbon atom of a carborane. Features of the structure are compared with related features of other organolithium compounds, and used to calculate the cone angles and steric requirements of icosahedral carboranyl and methylcarboranyl ligands attached to metal atoms of various sizes.  相似文献   

6.
Five novel phosphate-type hybrid surfactants, CmF2m+1C6H4CH[OPO2(OC6H5)Na]CnH2n+1 (FmPHnPPhNa: m = 4, 6, 8; n = 3, 5), have been synthesized. When compared with sulfate-type hybrid surfactants, CmF2m+1C6H4CH(OSO3Na)CnH2n+1 (C6H4 = p-phenylene), the new hybrid surfactants were found to have comparable abilities to lower the surface tension of water. The critical micelle concentrations of FmPHnPPhNa followed Klevens’ rule and their occupied areas per molecule increased with increasing m and n. Calcium hydroxyapatite (CaHAp) pellets modified with FmPH3PPhNa gave high hydro and lipophobic surfaces. The hybrid surfactants are expected to be useful as new dental reagents for oral hygiene.  相似文献   

7.
The reaction of TlCl3 with RLi leads to complexes of the general formula TlR2Cl (R = C6F5, p-C6F4H, m-C6F4H, 2,4,6-C6F3H2, p-C6FH4 or m-CF3C6H4). Some of these undergo oxidative addition reactions with gold(I) complexes to give polyfluorophenyl derivatives of the types AuR2ClL and Au(C6F5)R2(tht) (tht = tetrahydrothiophen), and with SnCl2 to give oily materials from which stable solids of the general formula Q[SnR2Cl3] can be isolated by addition of QCl (Q = Et4N or Ph3BzP).  相似文献   

8.
The highly electrophilic borane B(C6F5)3 reacts with e.g., n-octadecanol (n-C18H37OH) and n-octadecanethiol (n-C18H37SH) to form equilibrium mixtures of the reactants and their 1:1 adducts (n-C18H37EH)B(C6F5)3 (E = O, S). The latter are acidic, and react with Cp∗MMe3 (M = Ti, Hf) in polar and non-polar solvents to give methane and the unstable complexes [Cp∗MMe2][(n-C18H37E)B(C6F5)3]. The latter are very good initiators for the copolymerization of isobutene with isoprene at relatively high temperatures, giving high conversions to high molecular weight isobutene-isoprene copolymers. The weight average molecular weights are unusually high for the temperatures used, consistent with current theories of the role of weakly coordinating anions. The effects of changing the substituents on the alcohols are also investigated.  相似文献   

9.
Five novel phosphate-type hybrid surfactants, CmF2m+1C6H4CH[OPO2(OC6H5)Na]CnH2n+1 (FmPHnPPhNa: m = 4, 6, 8; n = 3, 5; C6H4 = p-phenylene, C6H5 = phenyl), have been synthesized. When compared with sulfate-type hybrid surfactants, CmF2m+1C6H4CH(OSO3Na)CnH2n+1 (C6H4 = p-phenylene), the new hybrid surfactants are found to have comparable abilities to lower surface tension of water. The critical micelle concentrations of FmPHnPPhNa follow Klevens rule and their occupied areas per molecule increase with increasing m and n. Calcium hydroxyapatite (CaHAp) pellets modified with FmPH3PPhNa gives high hydrophobic and lipophobic surfaces. The hybrid surfactants are expected as new dental reagents for oral hygiene.  相似文献   

10.
Irradiation of solutions of n5-C5H5W(CO)3R (R  CH3n1-CH2C6H5) in cyclohexane at ca. 310490 nm leads to the formation of [n5-C5H5W(CO)3]2 and methane and of n5-C5H5W5(CO)2(n3-CH2C6H5) and some [n5-C5H5W(CO)3]2, respectively. When the irradiation is carried out in the presence of excess P(C6H5)3, the photoproducts are n5-C5H5W(CO)2[P(C6H5)3]CH3 (R  CH3) and n5-C5H5W(CO)2(n3-CH2C6H5) and trace [n5-C5H5W(CO)3]2 (R  n1-CH2C6H5). Photolysis of the n5-C5H5W(CO)3R in the presence of benzyl chloride affords n5-C5H5W(CO)3Cl (R  CH3) and both n5-C5H5W(CO)2(n3-CH2C2H5) and n5-C5H5W(CO)3Cl (R  n1-CH2C6H5), the relative amounts of the latter products depending on the quantity of added C6H5CH2Cl. Irradiation of n5-C5H5W(CO)3-CH3 in the presence of both P(C6h5)3 and C6H5CH2Cl affords n5-C5H5W(CO)2-[P(C6H5)3]CH3, but no n5-C5H5W(CO)3Cl. It is proposed that the primary photo-reaction in these transformations is dissociation of a CO group from n5-C5H5W-(CO)3R to generate n5-C5H5W(CO)2R, which can either combine with L to form a stable 18 electron complex, n5-C5H5W(CO)2(L)R (L  CO, P(C5H5)3; LR  n3-CH2C6H5), or lose the group R in a competing, apparently slower step. This proposal receives support from the observation that, light intensifies being equal, n5-C5H5W(CO)3CH3 undergoes a considerably faster photoconversion to [n5-C5H5W(CO)3]2 under argon than under carbon monoxide.  相似文献   

11.
Li[C6F5B(OMe)3], Li[C6HF4B(OMe)3] (all three isomers) and Li[3,4,5-C6H2F3B(OMe)3] are the first examples of polyfluorophenyltrimethoxyborate salts which have been applied as reagents to Pd-catalysed cross-coupling reactions. A series of polyfluorinated biphenyls C6H5−nFn-C6H4F-4′ were obtained from Li[C6H5−nFnB(OMe)3] and the model substrate 4-FC6H4I in the presence of Pd catalysts. The influence of the number and the position of fluorine atoms in the polyfluorophenyltrimethoxyborate salts on the reactivity in the coupling reaction was elucidated.  相似文献   

12.
Reaction of closo-1,5-C2B3H5 with Cl2 under reduced temperatures in an inert solvent gives 2-Cl-1,5-C2B3H4. Using a hot/cold reactor a mixture of BMe3 and 1,5-C2B3H5 is converted to a combination of B-mono-, di-, and tri-methyl derivatives of this smallest closo carborane. In addition, B-mono-, di-, tri-, and tetramethyl derivatives of 2,2-?C2B3H4C2B3H4, as well as the parent dimer, are produced.  相似文献   

13.
Phosphonic acids [(HO)2P(O)C2H4CnF2n+1] (n = 4, 6) and [(HO)2P(O)C6H4-4-CnF2n+1] (n = 0, 1, 6) have been prepared in good yields. Deprotonation and reaction with cis-[PtCl2(PPh3)2] affords fluorinated platinum complexes which have been characterised by elemental analysis, mass spectrometry, IR and NMR spectroscopies. The structures of [Pt{O2P(O)C6H4-4-F}(PPh3)2], [Pt{O2P(O)C6H4-4-CF3}(PPh3)2] and [Pt{O2P(O)C2H4C6F13}(PPh3)2] have been determined by single crystal X-ray diffraction.  相似文献   

14.
Fluorinated organodifluoroboranes RfBF2 are in general suitable reagents to transform XeF2 and RIF2 into the corresponding onium tetrafluoroborate salts [RfXe][BF4] and [R(Rf)I][BF4], respectively. (4-C5F4N)BF2 and trans-CF3CFCFBF2 which represent boranes of high acidity form no Xe-C onium salts in reactions with XeF2 but give the desired iodonium salts with RIF2 (R = C6F5, o-, m-, p-C6FH4). The reaction of (4-C5F4N)BF2 with XeF2 ends with a XeF2-borane adduct. C6F5Xe(4-C5F4N), the first Xe-(4-C5F4N) compound, was obtained when C6F5XeF was reacted with Cd(4-C5F4N)2. We describe the synthesis of (4-C5F4N)IF2 and reactions of (4-C5F4N)IF2 and C6F5IF2 with (4-C5F4N)BF2. Analogous to [(4-C5F4N)2I][BF4] and [C6F5(4-C5F4N)I][BF4] aryl(perfluoroalkenyl)iodonium salts [R(R′)I][BF4] were obtained from RIF2 (R = C6F5, o-, m-, p-C6FH4) and R′BF2 (R′ = trans-CF3CFCF, CF2CF). The gas phase fluoride affinities pF of selected fluoroorganodifluoroboranes RfBF2 and their hydrocarbon analogs are calculated (B3LYP/6-31+G*) and discussed with respect to their potential to introduce Rf-groups into hypervalent EF2 bonds. Four aspects which influence the transformation of hypervalent EF2 bonds (E = Xe, R′I) under the action of Lewis acidic reagents RAFn−1 (A = B, P; n = 3, 5) into the corresponding [RE][AFn+1] salts are presented and the important role of the acidity is emphasized. Fluoride affinities may help to plan the introduction of organo groups into EF2 moieties and to expand the types of acidic reagents. Thus C6H5PF4 with a pF value comparable to that of RfBF2 compounds is able to introduce the C6H5 group into RIF2 (R = C6F5, p-C6FH4).  相似文献   

15.
New experimental results on perfluoroalkylation of C60 and C70 with the use of RfI (Rf = CF3, C2F5, n-C3F7, n-C4F9, and n-C6F13), along with a critical overview of the existing synthetic methods, are presented. For the selected new fullerene (Rf)n compounds we report spectroscopic, electrochemical and structural data, including improved crystallographic data for the isomers of C70(C2F5)10 and C60(C2F5)10, and the first X-ray structural data for the dodecasubstituted perfluoethylated C70 fullerene, C70(C2F5)12, which possesses unprecedented addition pattern.  相似文献   

16.
A new chemical oxidant [N(4-C6H4Br)3][B(C6F5)4], was prepared and used to synthesize [Fe(C5H5)2][B(C6F5)4]. The crystal structure of [Fe(C5H5)2][B(C6F5)4] was determined.  相似文献   

17.
The 1∶2 molar reactions of tin(IV) chloride with the Schiff bases, CH3C(OH):CHC(CH3):NR and 2 HOC10H6CH:NR′ (where R=C2H5,n-C3H7 orn-C4H9 and R′=C6H5, C2H5,n-C4H9 ort-C4H9) have resulted in the synthesis of SnCl4·(SBH)2 type derivatives (whereSBH represents the Schiff base molecule). These have been characterized by elemental analysis, conductivity measurements and IR spectral studies.  相似文献   

18.
Tris(pentafluorophenyl)borane, B(C6F5)3 reacts with triethylaluminum, AlEt3 to a mixture of Al(C6F5)3−nEtn and Al2(C6F5)6−nEtn compounds depending on the B/Al ratio. From excess borane to excess AlEt3 the species Al(C6F5)3 → Al(C6F5)2Et Al2(C6F5)4Et2 → Al2(C6F5)3Et3 → Al2(C6F5)2Et4 → Al2(C6F5)Et5 are formed and differentiated by their para-F signal in 19F NMR. The reaction between B(C6F5)3 and the higher aluminum alkyls, tri(iso-butyl)aluminum and tri(n-hexyl)aluminum AlR3 (R = i-Bu, n-C6H13) is slower and requires AlR3 excess to shift the C6F5 R exchange equilibria to almost complete formation of Al(C6F5)R2 and BR3. At equimolar ratio the equilibrium lies on the side of the unchanged borane together with its boranate [B(C6F5)3R] anion. For tri(n-octyl)aluminum even at large Al(n-C8H17)3 excess no C6F5 alkyl exchange can be observed, but boranate anions form.  相似文献   

19.
The reaction of the neutral carborane C2B9H13 with Cp*M(CH3)3 (M = Zr (a), Hf (b); Cp* = η5-C5Me5) yields [Cp(C2B9H11)M(CH3)]n (3a, b). Complexes 3a, b form THF adducts Cp*(C2B9H11)M(CH3)(THF) 4, insert 2-butyne to yield Cp*(C2B9H11)M{C(Me=CMe2} 5, and undergo methane elimination upon thermolysis to yield methylene-bridged complexes [Cp*(C2B9H11)M]2(μ-CH2) (6). These chemical studies, and companion structural and theoretical studies establish that 3a, b are neutral analogues of the cationic Cp2M(R)+ species (1; Cp = η5-C5H5) and Cp2M(R)(L)+ (2) which are believed to be active in Cp2MX2-based Ziegler catalysts. Despite the lower metal charge, 3–6 exhibit characteristic “electrophilic metal alkyl” properties including agostic M-H-C and M-H-B interactions, high insertion and intramolecular C-H activation reactivity, and high ethylene polymerization and propene oligomerization activity. These observations suggest that the key requirement for high insertion/polymerization activity in metallocene systems is high metal unsaturation (i.e. two empty metal-centered orbitals) rather than charge.  相似文献   

20.
The new ruthenium(II) complex [(C8H10)RuCl2]n (1) (C8H10 = 1,3,5-cyclooctatriene; n ⩾ 2) has been obtained from the reaction of RuCl3·xH2O with 1,3,5,7-cyclooctatetraene in refluxing ethanol. Reduction of [(C8H10)RuCl2]n and [(C7H8)RuCl2]2 (2) (C7H8 = 1,3,5-cyclooctatriene) by Na/Hg amalgam in the presence of isoprene (C5H8) gives the novel ruthenium(O) complexes [(η6-C8H10)Ru(η4-C5H8)] (3) and [(η6-C7H8)Ru(η4-C5H8)] (4). [(η6-C7H8Ru(η4-C5H8)] reacts with CO and HBF4 to give [(η6-C7H8)Ru(η3-C5H9)(CO)][BF4] (C5H9 = trans-1,2-dimethylallyl (5a); 1,1-dimethylallyl (5b)).  相似文献   

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