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1.
The systematic study of the reaction of M[PF6] salts and Me3SiCN led to a synthetic method for the synthesis and isolation of a series of salts containing the unprecedented [PF2(CN)4]? ion in good yields. The reaction temperature, pressure, and stoichiometry were optimized. The crystal structures of M[PF2(CN)4] (M=[nBu4N]+, Ag+, K+, Li+, H5O2+) were determined. X‐ray crystallography showed the exclusive formation of the cis isomer in accord with 31P and 19F solution NMR spectroscopy data. Starting with the K[PF2(CN)4] the room temperature ionic liquid EMIm[PF2(CN)4] was prepared exhibiting a rather low viscosity.  相似文献   

2.
The [Ag]+‐catalyzed exchange of coordinated cyanide in [Fe(CN)6]4? by phenylhydrazine (PhNHNH2) has been studied spectrophotometrically at 488 nm by monitoring increase in the absorbance for the formation of cherry red colored complex [Fe(CN)5PhNHNH2]3?. The other reaction conditions were pH 2.80±,0.02, temperature = 30.0 ± 0.1°C, and ionic strength (I) = 0.02 M (KNO3). The reaction was followed as a function of pH, ionic strength, temperature, [Fe(CN)4?6], [PhNHNH2], [Ag+] by varying one variable at a time. The initial rates were evaluated for each variation using the plane mirror method. The initial rates evaluated as a function of [Fe(CN)4?6] clearly indicate that the initial rate increases with the increase in [Fe(CN)4?6] and finally reaches to a limiting value when [Fe(CN)4?6]/[AgNO3] ? 1000. It indicates the formation of a strong adduct between [Fe(CN)6]4? and AgNO3 prior to the abstraction of CN?. The variation in initial rates with [PhNHNH2] also showed limiting values at [Fe(CN)4?6]/[PhNHNH2] ? 8.30. The complex behavior due to pH and [Ag+] variations on the rate has been explained in detail. The composition of the final reaction product [Fe(CN)5PhNHNH2] formed during the course of reaction has been found to be 1:1 using the mole ratio method. The evaluated values of activation parameters for the catalyzed reaction are Ea = 53.85 kJ mol?1, Δ H, = 51.33 kJ mol?1, and Δ S = ?134.63 J K?1 mol?1, which suggest an interchange dissociative mechanism. A most plausible mechanistic scheme has been proposed based on the experimental observations. © 2007 Wiley Periodicals, Inc. Int J Chem Kinet 39: 447–456, 2007  相似文献   

3.
A series of novel α‐fluoroalkyl ammonium salts was obtained from the corresponding cyano compounds or nitriles by reaction with anhydrous HF. Room‐temperature stable trifluoromethyl ammonium salts were obtained in quantitative yield in a one‐step reaction at ambient temperature from the commercially available starting materials BrCN or ClCN. The novel cations [CF3CF2NH3]+, [HCF2CF2NH3]+, and [(NH3CF2)2]2+ were obtained from CF3CN, HCF2CN, and (CN)2, respectively, and anhydrous HF. The aforementioned fluorinated ammonium cations were isolated as room temperature stable [AsF6]? and/or [SbF6]? salts, and characterized by multi‐nuclear NMR and vibrational spectroscopy. The salts [HCF2NH3][AsF6] and [CF3NH3][Sb2F11] were characterized by their X‐ray crystal structure.  相似文献   

4.
The reaction of MnII and [NEt4]CN leads to the isolation of solvated [NEt4]Mn3(CN)7 ( 1 ) and [NEt4]2Mn3(CN)8 ( 2 ), which have hexagonal unit cells [ 1 : R$\bar 3$ m, a=8.0738(1), c=29.086(1) Å; 2 : P$\bar 3$ m1, a=7.9992(3), c=14.014(1) Å] rather than the face centered cubic lattice that is typical of Prussian blue structured materials. The formula units of both 1 and 2 are composed of one low‐ and two high‐spin MnII ions. Each low‐spin, octahedral [MnII(CN)6]4? bonds to six high‐spin tetrahedral MnII ions through the N atoms, and each of the tetrahedral MnII ions are bound to three low‐spin octahedral [MnII(CN)6]4? moieties. For 2 , the fourth cyanide on the tetrahedral MnII site is C bound and is terminal. In contrast, it is orientationally disordered and bridges two tetrahedral MnII centers for 1 forming an extended 3D network structure. The layers of octahedra are separated by 14.01 Å (c axis) for 2 , and 9.70 Å (c/3) for 1 . The [NEt4]+ cations and solvent are disordered and reside between the layers. Both 1 and 2 possess antiferromagnetic superexchange coupling between each low‐spin (S=1/2) octahedral MnII site and two high‐spin (S=5/2) tetrahedral MnII sites within a layer. Analogue 2 orders as a ferrimagnet at 27(±1) K with a coercive field and remanent magnetization of 1140 Oe and 22 800 emuOe mol?1, respectively, and the magnetization approaches saturation of 49 800 emuOe mol?1 at 90 000 Oe. In contrast, the bonding via bridging cyanides between the ferrimagnetic layers leads to antiferromagnetic coupling, and 3D structured 1 has a different magnetic behavior to 2 . Thus, 1 is a Prussian blue analogue with an antiferromagnetic ground state [Tc=27 K from d(χT)/dT].  相似文献   

5.
Starting from fluoridosilicate precursors in neat cyanotrimethylsilane, Me3Si?CN, a series of different ammonium salts [R3NMe]+ (R=Et, nPr, nBu) with the novel [SiF(CN)5]2? and [Si(CN)6]2? dianions was synthesized in facile, temperature controlled F?/CN? exchange reactions. Utilizing decomposable, non‐innocent cations, such as [R3NH]+, it was possible to generate metal salts of the type M2[Si(CN)6] (M+=Li+, K+) via neutralization reactions with the corresponding metal hydroxides. The ionic liquid [BMIm]2[Si(CN)6] (m.p.=72 °C, BMIm=1‐butyl‐3‐methylimidazolium) was obtained by a salt metathesis reaction. All the synthesized salts could be isolated in good yields and were fully characterized.  相似文献   

6.
Mn(TCNE)[C4(CN)8]1/2 (TCNE=tetracyanoethylene) and [NEt4]MnII3(CN)7 have extended layers with nearest neighbor intralayer S=5/2 and S=1/2 spin sites that couple antiferromagnetically forming ferrimagnetic layers. These layers are uniformly connected via diamagnetic (nonmagnetic) bridging μ4‐[(C4(CN)8]2? (8.77 Å) or μ‐CN (5.48 Å) ligands, respectively, that antiferromagnetic couple the ferrimagnetic layers resulting in an antiferromagnet. The Jinter/kB is ?1.0 and ?1.8 K (H=?JSi?Sj) for Mn(TCNE)[C4(CN)8]1/2 and [NEt4]MnII3(CN)7, respectively. Albeit intrinsically multilayered, these antiferromagnets have the same motif as that for artificial/synthetic antiferromagnets that exhibit giant magnetoresistance (GMR) and are commercially used in many magnetic memory applications.  相似文献   

7.
The novel thiodiphosphate, [Na(12‐crown‐4)2]2[P2S6] · CH3CN, bis[di(12‐crown‐4)sodium] hexathiodiphosphate(V) acetonitrile solvate ( 1 ) has been synthesized by the reaction of Na2[P2S6] with 12‐crown‐4 in dry acetonitrile. The title compound crystallizes in the tetragonal space group P42/mbc (no. 135), with a = 15.184(1) Å, c = 21.406(2) Å and Z = 4 and final R1 = 0.0671 and wR2 = 0.0809. The crystal structure is characterized by discrete sodium‐bound crown‐ether sandwich cations, [Na(12‐crown‐4)2]+ and [P2S6]2? ions with D2h symmetry. Sodium ion is coordinated by the eight oxygen atoms of two crown‐ether molecules to form a square antiprisma. Solvent molecules of CH3CN are statistically disordered. Distances and angles of the [P2S6]2? unit are similar to those in [K(18‐crown‐6)]2 [P2S6] · 2 CH3CN, and in K2[P2S6] and Cs2[P2S6]. The FT‐Raman and FT‐IR spectrum of the title compound has been recorded and interpreted, especially with respect to the P2S6 group and in comparison to the few known metal hexathiodiphosphates(V).  相似文献   

8.
Although pure hydrogen cyanide can spontaneously polymerize or even explode, when initiated by small amounts of bases (e.g. CN?), the reaction of liquid HCN with [WCC]CN (WCC=weakly coordinating cation=Ph4P, Ph3PNPPh3=PNP) was investigated. Depending on the cation, it was possible to extract salts containing the formal dihydrogen tricyanide [CN(HCN)2]? and trihydrogen tetracyanide ions [CN(HCN)3]? from liquid HCN when a fast crystallization was carried out at low temperatures. X‐ray structure elucidation revealed hydrogen‐bridged linear [CN(HCN)2]? and Y‐shaped [CN(HCN)3]? molecular ions in the crystal. Both anions can be considered members of highly labile cyanide‐HCN solvates of the type [CN(HCN)n]? (n=1, 2, 3 …) as well as formal polypseudohalide ions.  相似文献   

9.
CuCl or pre‐generated CuCF3 reacts with CF3SiMe3/KF in DMF in air to give [Cu(CF3)4]? quantitatively. [PPN]+, [Me4N]+, [Bu4N]+, [PhCH2NEt3]+, and [Ph4P]+ salts of [Cu(CF3)4]? were prepared and isolated spectroscopically and analytically pure in 82–99 % yield. X‐ray structures of the [PPN]+, [Me4N]+, [Bu4N]+, and [Ph4P]+ salts were determined. A new synthetic strategy with [Cu(CF3)4]? was demonstrated, involving the removal of one CF3? from the Cu atom in the presence of an incoming ligand. A novel CuIII complex [(bpy)Cu(CF3)3] was thus prepared and fully characterized, including by single‐crystal X‐ray diffraction. The bpy complex is highly fluxional in solution, the barrier to degenerate isomerization being only 2.3 kcal mol?1. An NPA study reveals a huge difference in the charge on the Cu atom in [Cu(CR3)4]? for R=F (+0.19) and R=H (+0.46), suggesting a higher electron density on Cu in the fluorinated complex.  相似文献   

10.
Solutions of butylzinc iodide in tetrahydrofuran, acetonitrile, and N,N‐dimethylformamide were analyzed by electrospray ionization mass spectrometry. In all cases, microsolvated butylzinc cations [ZnBu(solvent)n]+, n=1–3, were detected. The parallel observation of the butylzincate anion [ZnBuI2]? suggests that these ions result from disproportionation of neutral butylzinc iodide in solution. In the presence of simple bidentate ligands (1,2‐dimethoxyethane, N,N‐dimethyl‐2‐methoxyethylamine, and N,N,N′,N′‐tetramethylethylenediamine), chelate complexes of the type [ZnBu(ligand)]+ form quite readily. The relative stabilities of these complexes were probed by competition experiments and analysis of their unimolecular gas‐phase reactivity. Fragmentation of mass‐selected [ZnBu(ligand)]+ leads to the elimination of butene and formation of [ZnH(ligand)]+. In marked contrast, the microsolvated cations [ZnBu(solvent)n]+ lose the attached solvent molecules upon gas‐phase fragmentation to produce bare [ZnBu]+, which subsequently dissociates into [C4H9]+ and Zn. This difference in reactivity resembles the situation in organozinc solution chemistry, in which chelating ligands are needed to activate dialkylzinc compounds for the nucleophilic addition to aldehydes.  相似文献   

11.
A series of gold acetonitrile complexes [Au(NCMe)2]+[WCA]? with weakly coordinating counterions (WCAs) was synthesized by the reaction of elemental gold and nitrosyl salts [NO]+[WCA]? in acetonitrile ([WCA]? = [GaCl4]?, [B(CF3)4]?, [Al(ORF)4]?; RF = C(CF3)3). In the crystal structures, the [Au(NCMe)2]+ units appeared as monomers, dimers, or chains. A clear correlation between the aurophilicity and the coordinating ability of counterions was observed, with more strongly coordinating WCAs leading to stronger aurophilic contacts (distances, C?N stretching frequencies of [Au(NCMe)2]+ units). An attempt to prepare [Au(L)2]+ units, even with less weakly basic solvents like CH2Cl2, led to decomposition of the [Al(ORF)4]? anion and formation of [NO(CH2Cl2)2]+[F(Al(ORF)3)2]?. All nitrosyl reagents [NO]+[WCA]? were generated according to an optimized procedure and were thoroughly characterized by Raman and NMR spectroscopy. Moreover, the to date unknown species [NO]+[B(CF3)3CN]? was prepared. Its reaction with gold unexpectedly produced [Au(NCMe)2]+[Au(NCB(CF3)3)2]?, in which the cyanoborate counterion acts as an anionic ligand itself. Interestingly, the auroborate anion [Au(NCB(CF3)3)2]? behaves as a weakly coordinating counterion, which becomes evident from the crystallographic data and the vibrational spectral characteristics of the [Au(NCMe)2]+ cation in this complex. Ligand exchange in the only room temperature stable salt of this series, [Au(NCMe)2]+[Al(ORF)4]?, is facile and, for example, [Au(PPh3)(NCMe)]+[Al(ORF)4]? can be selectively generated. This reactivity opens the possibility to generate various [AuL1L2]+[Al(ORF)4]? salts through consecutive ligand‐exchange reactions that offer access to a huge variety of AuI complexes for gold catalysis.  相似文献   

12.
Compound {[Cu(II)/Cu(I)]2(ophen)4(Htpt)}?2H2O ( 1 ) was obtained by hydrothermal reaction. Compound 1 is a mixed‐valence copper coordination complex with a different coordination environment. The X‐ray structural analysis of 1 revealed two crystallographically independent dimeric [Cu2(ophen)2]+ units bridged by two µ1‐carboxylate groups of the tpt ligand into a butterfly‐shaped molecule in the crystal structure. Compound [Cu(I)3(CN)3(phen)3] ( 2 ) was synthesized using ethanol instead of water, and consisted of an infinite helix chain formed from [Cu(I)(phen)]+ units bridged by cyano groups. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

13.
Exploiting thiacalix 4 arene and sulfur‐bridged bisphenolates as ligands for bioinorganic studies involving iron(III) requires the prior development of synthetic routes (varying substituents and reaction conditions) to construct complexes with low nuclearities and accessible coordination sites, which was in the focus of this investigation. Treating ptert‐butylthiacalix 4 arene (H4TC) and 1, 4‐dimethyl‐ptert‐butylthiacalix 4 arene (Me2H2TC) with Fe[N(SiMe3)2]3 yielded in the formation of the iron(III) complexes [(Me3SiTC)2Fe2] ( 1 ) and [(Me2TC)3Fe2] ( 3 ), respectively. While 1 is a sandwich compound, in 3 one [Me2TC]2– unit is bridging two [Me2TCFe]+ moieties. Employing thiobisphenolates as ligands it turned out, that in dependence on the residues R and the preparation method it is possible to selectively access sandwich, anionic or neutral complexes, which were shown to contain central high‐spin iron(III) atoms. The syntheses, structures, and electronic properties of three iron(III) bisphenolate complexes, [ClL2Fe]NEt3H ( 4 ), [MeLFeCl2]NEt3H ( 5 ), and [tBuLFeCl(thf)] ( 7 ) are discussed.  相似文献   

14.
Understanding the effects of intermolecular interactions on metal‐to‐metal charge transfer (MMCT) is crucial to develop molecular devices by grafting MMCT‐based molecular arrays. Herein, we report a series of solvent‐free {Fe2Co2} compounds sharing the same cationic tetranuclear {[Fe(PzTp)(CN)3]2[Co(dpq)2]2}2+ (PzTp?=tetrakis(pyrazolyl)borate, dpq=dipyrido[3,2‐d:2′,3′‐f]quinoxaline) square units but having anions with different size, including BF4?, PF6?, OTf?, and [Fe(PzTp)(CN)3]?. Intermolecular π???π interactions between dpq ligands, which coordinate to cobalt ions in the {[Fe(PzTp)(CN)3]2[Co(dpq)2]2}2+ units, can be modulated by introducing different counterions, regulating the distortion of the CoN6 octahedron and ligand field around the cobalt ions. This change results in different MMCT behavior. Computational analyzes reveal the substantial role of the intermolecular interactions tuned by the presence of different counteranions on the MMCT behavior.  相似文献   

15.
The kinetics of stripping of Ni2+ from a Ni‐BTMPPA complex, dissolved in a kerosene solution of BTMPPA (H2A2, Cyanex 272), by acidic sulfate‐acetato solution, was studied using the single (falling) drop technique and flux (F) method of data treatment. The empirical flux equation at 303 K is Fb (kmol/m2s) = 10?4.35 [Ni2+] (1+10?3.42 [H+]?1)?1 ([H2A2](o)0.5+2.50 [H2A2](o))?1 (1+6[SO42?]) (1+3.20 [Ac?]). Activation energy (Ea), entropy change in activation (ΔS±), and enthalpy change in activation (ΔH±) were measured under different experimental conditions. Based on the empirical flux equation, Ea and ΔS±, the mechanism of Ni2+ stripping is provided. In a low [H+] region, the stripping reaction steps appear as [NiA+] → Ni2+ + A? and [Ni(HA2)2](int) → [NiHA2]+(int) + HA2(int)? in lower and higher concentration regions of free BTMPPA, respectively, provided [SO42?] and [Ac?] are kept low. However, at higher [H+] concentrations, the stripping is under diffusion control. With increasing [SO42?] and [Ac?], the enhancement of the rate is attributed to the attack of the Ni(II) complex by SO42? or HSO4? and Ac? to form NiSO4 or NiHSO4+ and NiAc+ complexes. Negative ΔS± values indicate that the rate‐determining stripping reaction steps occur via an substitution nucleophilic, bimolecular (SN2) mechanism.  相似文献   

16.
Complexes [NiI3(mpta)2]I ( 1 ) and [NiI3(ppta)2]I ( 2 ) have been synthesized by reaction of nickel(II) halide salts with ‐1‐methyl‐1‐azonia‐3,5‐diaza‐7‐phosphatricyclo[3.3.1.13,7]decane iodide (mpta+I?) and 1‐(n‐propyl)‐1‐azonia‐3,5‐diaza‐7‐phosphatricyclo[3.3.1.13,7]decane bromide (ppta+Br?) respectively. The crystal structures of compounds 1 and 2 are described and are similar, with both compounds crystallizing in monoclinic space groups. The geometry about both nickel atoms is that of a trigonal bipyramid with the cationic phosphine ligands found in the axial positions and the iodide ligands arranged in the equatorial plane.  相似文献   

17.
The Tetracyanoborates M[B(CN)4], M = [Bu4N]+, Ag+, K+ The tetracyanoborate anion is prepared for the first time as the tetrabutylammonium salt by the reaction of [NBu4]BX and BX3 (X = Br, Cl) in toluene with KCN. After purification and recrystallization of the product from CHCl3 colorless and needle size single crystals of [Bu4N][B(CN)4] are formed. After metathesis with AgNO3 the silver salt and subsequently with KBr the potassium salt is prepared. The three salts are characterized by single crystal X‐ray diffraction (Ag[B(CN)4] P 43m, a = 5.732(1) Å, V = 188.3 Å3, Z = 1, R1 = 0.75%; K[B(CN)4] I41/a, a = 6.976(1), c = 14.210(3) Å, V = 691.5 Å3, Z = 4, R1 = 1.90%; [Bu4N][B(CN)4] Pnna, a = 17.765(3), b = 11.650(2), c = 11.454(2) Å, V = 2370.5 Å3, Z = 4, R1 = 6.09%) and by NMR‐, IR‐, Raman‐ as well by UV‐spectroscopy.  相似文献   

18.
Reaction of the donor‐stabilized silylene 1 (which is three‐coordinate in the solid state and four‐coordinate in solution) with [HMCp(CO)3] (M=Mo, W; Cp=cyclopentadienyl) leads to the cationic five‐coordinate silicon(IV) complexes 2 and 3 , respectively, and reaction of 1 with CH3COOH yields the neutral six‐coordinate silicon(IV) complex 4 . Compounds 2 – 4 were structurally characterized by crystal structure analyses and multinuclear NMR spectroscopic studies in the solid state and in solution. The formation of 2 – 4 can be formally described in terms of a Brønsted acid/base reaction, coupled with a redox process (SiII→SiIV, H+→H?).  相似文献   

19.
Carbon‐atom extrusion from the ipso‐position of a halobenzene ring (C6H5X; X=F, Cl, Br, I) and its coupling with a methylene ligand to produce acetylene is not confined to [LaCH2]+; also, the third‐row transition‐metal complexes [MCH2]+, M=Hf, Ta, W, Re, and Os, bring about this unusual transformation. However, substrates with substituents X=CN, NO2, OCH3, and CF3 are either not reactive at all or give rise to different products when reacted with [LaCH2]+. In the thermal gas‐phase processes of atomic Ln+ with C7H7Cl substrates, only those lanthanides with a promotion energy small enough to attain a 4fn5d16s1 configuration are reactive and form both [LnCl]+ and [LnC5H5Cl]+. Branching ratios and the reaction efficiencies of the various processes seem to correlate with molecular properties, like the bond‐dissociation energies of the C?X or M+?X bonds or the promotion energies of lanthanides.  相似文献   

20.
A Pd‐catalyzed Suzuki cross‐coupling of arylboronic acids with Yagupolskii–Umemoto reagents was explored. In contrary to trifluoromethylations, the Pd‐catalyzed reaction of R?B(OH)2 and [Ar2SCF3]+[OTf]? provided the arylation products (R?Ar) in good to high yields. The reaction confirms that the S?Ar bonds of [Ar2SCF3]+[OTf]? can be readily cleaved in the presence of Pd complexes. The relatively electron‐poor aryl groups of asymmetric [Ar1Ar2SCF3]+[OTf]? salts are more favorably transferred compared to the electron‐rich ones. This reaction represents the first report of utilization of [Ar2SCF3]+[OTf]? as arylation reagents in organic synthesis.  相似文献   

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