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1.
Reactions of the oxorhenium(V) complexes [ReOX3(PPh3)2] (X = Cl, Br) with the N‐heterocyclic carbene (NHC) 1,3,4‐triphenyl‐1,2,4‐triazol‐5‐ylidene (LPh) under mild conditions and in the presence of MeOH or water give [ReOX2(Y)(PPh3)(LPh)] complexes (X = Cl, Br; Y = OMe, OH). Attempted reactions of the carbene precursor 5‐methoxy‐1,3,4‐triphenyl‐4,5‐dihydro‐1H‐1,2,4‐triazole ( 1 ) with [ReOCl3(PPh3)2] or [NBu4][ReOCl4] in boiling xylene resulted in protonation of the intermediately formed carbene and decomposition products such as [HLPh][ReOCl4(OPPh3)], [HLPh][ReOCl4(OH2)] or [HLPh][ReO4] were isolated. The neutral [ReOX2(Y)(PPh3)(HLPh)] complexes are purple, airstable solids. The bulky NHC ligands coordinate monodentate and in cis‐position to PPh3. The relatively long Re–C bond lengths of approximate 2.1Å indicate metal‐carbon single bonds.  相似文献   

2.
Structures of New Bis(pentafluorophenyl)halogeno Mercurates [{Hg(C6F5)2}3(μ‐X)] (X = Cl, Br, I) From the reactions of [PNP]Cl or [PPh4]Y (Y = Br, I) with Hg(C6F5)2 crystals of the composition [Cat][{Hg(C6F5)2}3X] (Cat = PNP, X = Cl ( 1 ); Cat = PPh4, X = Br ( 2 ), I ( 3 )) are formed. 1 crystallizes in the triclinic space group P1¯, 2 and 3 crystallize isotypically in the monoclinic space group C2/c. In the crystals the halide anions are surrounded by three Hg(C6F5)2 molecules. The reaction of [PPh4]Br with Hg(C6F5)2 under slightly changed conditions gives the compound [PPh4]2[{Hg(C6F5)2}3(μ‐Br)][{Hg(C6F5)2}2(μ‐Br)] ( 4 ).  相似文献   

3.
Three dinuclear copper(I) complexes, [Cu2(µ‐Cl)2(1,2‐(PPh2)2‐1,2‐C2B10H10)2]·2CH2Cl2 ( 1 ), [Cu2(µ‐Br)2(1,2‐(PPh2)2‐1,2‐C2B10H10)2]·2THF ( 2 ) and {Cu2(µ‐I)2[1,2‐(PPh2)2‐1,2‐C2B10H10]2} ( 3 ) have been synthesized by the reactions of CuX (X = Cl, Br and I) with the closo ligand 1,2‐(PPh2)2‐1,2‐C2B10H10. All these complexes were characterized by elemental analysis, FT‐IR, 1H and 13C NMR spectroscopy and X‐ray structure determination. Single crystal X‐ray structure determinations show that every complex contained di‐µ‐X‐bridged structure involving a crossed parallelogram plane formed by two Cu atoms and two X atoms (X = Cl, Br, I). The geometry at the Cu atom was a distorted tetrahedron, in which two positions were occupied by two P atoms of the PPh2 groups connected to the two C atoms of carborane (Cc), and the other two resulted from two X atoms which bridged the other Cu atom at the same time. To the best of our knowledge, this is the first example of copper(I) complexes with 1,2‐diphenylphosphino‐1,2‐dicarba‐closo‐dodecaborane as ligand characterized by X‐ray diffraction. The catalytic property of the complex 3 for the amination of iodobenzene with aniline was also investigated. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

4.
The tungsten complexes W(CO)4(NO)X, W(CO)3(NO)(PPh3)X and W(CO)2(NO)(PPh3)2X (X = Cl, Br and I) have been shown to be effective catalysts for the metathesis of 1,7-octadiene.  相似文献   

5.
The complexes [Ir(cod)Ln]PF6(I, L = PPh3, PMePh2; n = 2. L = PMe2Ph; n = 3) react with HX to give [IrHX(cod)L2]PF6 (II, L = PMePh2 or PMe2Ph) or [IrHX2(cod)(PPh3)] (III). The intermediates [IrX(cod)L2] have, in two cases (L = PMePh2, X = I, Br), been directly isolated from the reaction mixtures at 0°C, and are also formed from I with KX (L = PPh3, X = Cl; L = PMePh2, X = Cl, Br, I); these intermediates protonate to give II (L = PMePh2), or an equimolar mixture of III and I (L = PPh3, X = Cl). Surprisingly, I2 reacts with I in MeOH to give III (L = PPh3). The stereochemistries of II and III were determined by < 1H NMR and especially by new methods using 13C NMR spectroscopy. The complexes I exhibit a Lewis acid reactivity pattern.  相似文献   

6.
Abstract

Seven-coordinate complexes of molybdenum(II) and tungsten(II) have become increasingly important as homogeneous catalysts. For example, the complexes [MX2(CO)3L2] (M = Mo and W; X = Cl and Br; L = PPh3 and AsPh3) have been shown to be catalysts for the ring-opening polymerisation of norbornene.1 Although a wide variety of complexes of the type [MX2(CO)3L2] (M = Mo and W; X = Cl, Br and I; L = nitrogen, phosphorus, arsenic and antimony donor ligands)2 have been reported, until now no examples of the mixed complexes [MX2(CO)3(py)L] have been prepared. In this communication we wish to describe the synthesis of the new mixed pyridine/L compounds [MI2(CO)3(py)L] (M = Mo and W; L = PPh3, AsPh3 and SbPh3).  相似文献   

7.
The reaction of (C5Me5)2Th(CH3)2 with the phosphonium salts [CH3PPh3]X (X=Cl, Br, I) was investigated. When X=Br and I, two equivalents of methane are liberated to afford (C5Me5)2Th[CHPPh3]X, rare terminal phosphorano‐stabilized carbenes with thorium. These complexes feature the shortest thorium–carbon bonds (≈2.30 Å) reported to date, and electronic structure calculations show some degree of multiple bonding. However, when X=Cl, only one equivalent of methane is lost with concomitant formation of benzene from an unstable phosphorus(V) intermediate, yielding (C5Me5)2Th[κ2‐(C,C′)‐(CH2)(CH2)PPh2]Cl. Density functional theory (DFT) investigations of the reaction energy profiles for [CH3PPh3]X, X=Cl and I showed that in the case of iodide, thermodynamics prevents the production of benzene and favors formation of the carbene.  相似文献   

8.
The reaction of (C5Me5)2Th(CH3)2 with the phosphonium salts [CH3PPh3]X (X=Cl, Br, I) was investigated. When X=Br and I, two equivalents of methane are liberated to afford (C5Me5)2Th[CHPPh3]X, rare terminal phosphorano‐stabilized carbenes with thorium. These complexes feature the shortest thorium–carbon bonds (≈2.30 Å) reported to date, and electronic structure calculations show some degree of multiple bonding. However, when X=Cl, only one equivalent of methane is lost with concomitant formation of benzene from an unstable phosphorus(V) intermediate, yielding (C5Me5)2Th[κ2‐(C,C′)‐(CH2)(CH2)PPh2]Cl. Density functional theory (DFT) investigations of the reaction energy profiles for [CH3PPh3]X, X=Cl and I showed that in the case of iodide, thermodynamics prevents the production of benzene and favors formation of the carbene.  相似文献   

9.
The phenylimidorhenium(V) complexes [Re(NPh)X3(PPh3)2] (X = Cl, Br) react with the N‐heterocyclic carbene (NHC) 1,3‐diethyl‐4,5‐dimethylimidazole‐2‐ylidene (LEt) under formation of the stable rhenium(V) complex cations [Re(NPh)X(LEt)4]2+ (X = Cl, Br), which can be isolated as their chloride or [PF6]? salts. The compounds are remarkably stable against air, moisture and ligand exchange. The hydroxo species [Re(NPh)(OH)(LEt)4]2+ is formed when moist solvents are used during the synthesis. The rhenium atoms in all three complexes are coordinated in a distorted octahedral fashion with the four NHC ligands in equatorial planes of the molecules. The Re–C(carbene) bond lengths between 2.171(8) and 2.221(3) Å indicate mainly σ‐bonding between the NHC ligand and the electron deficient d2 metal atoms. Attempts to prepare analogous phenylimido complexes from [Re(NPh)Cl3(PPh3)2] and 1,3‐diisopropyl‐4,5‐dimethylimidazole‐2‐ylidene (Li?Pr) led to a cleavage of the rhenium‐nitrogen multiple bond and the formation of the dioxo complex [ReO2(Li?Pr)4]+.  相似文献   

10.
The catalytic activity of a series of indenylnickel(Ⅱ) halides: (1-R-Ind)Ni(PPh3)X (R=ethyl, cyclopentyl and benzyl, while X=Cl, Br and I), towards styrene polymerization was studied in the presence of NaBPh4 and PPh3. The catalytic property of these halides was related to the substituent group on the indenyl ligand and the halogen atom bonded to the metal atom. Among them, the (1-Et-Ind)Ni(PPh3)Cl/NaBPha/PPh3 system showed the highest activity for the polymerization of styrene, and the polystyrene obtained was a syndio-rich (rr triad) atactic polymer with Mn values in the range of 103--104. The mechanism of the styrene polymerization initiated by the (1-Et-Ind)Ni(PPh3)Cl/NaBPha/PPh3 system was studied.  相似文献   

11.
The reaction of Pt(PPh3)4 with CH2Cl1 in benzene yields the cationic ylide complex cis-[Pt(PPh3)2(CH2PPh3)Cl]I in high yield. This complex has been converted to cis-[(PPh3)2(CH2PPh3)X]X (X  Br or I) by reaction with LiBr or NaI. Reaction of cis-[Pt(PPH3)I]I with iodine yields cis-[Pt(PPh3)2(CH2PPh3)I]I3. Nmr data are given in support of the suggested structures.  相似文献   

12.
Summary The reduction of nickel(II) halides with NaBH4 in the presence of different ligands, L=PPh3, AsPh3, SbPh3, has been studied. With a molar ratio L/Ni=3, new complexes NiX(SbPh3)3, X=Cl, Br, I, were obtained. With a molar ratio L/Ni=2, dimeric species [NiXL2]2, X=Cl, Br, I; L=PPh3, AsPh3, SbPh3, were isolated. They are unstable and decompose easily in the solid and rapidly in solution, so that pure samples were only identified for X=Cl, L=PPh3, AsPh3, SbPh3; X=Br, L=PPh3 and X=I, L=PPh3. With a molar ratio L/Ni=1, complexes [NiXL]n (probably polymeric) were obtained. They are very unstable and pure samples could only be isolated when X=Cl, L=PPh3. Impure substances containing variable amounts of decomposition products were obtained in all the remaining cases. The chemical and structural behaviour of these complexes is discussed.  相似文献   

13.
Organometallic Compounds of Copper. XVIII. On the Reaction of the Alkyne Copper(I) Complexes [CuX(S‐Alkyne)] (X = Cl, Br, I; S‐Alkyne = 3,3,6,6‐Tetramethyl‐1‐thiacyclohept‐4‐yne) with the Phosphanes PMe3 and Ph2PCH2CH2PPh2 (dppe) The alkyne copper(I) halide complexes [CuX(S‐Alkyne)]n ( 2 ) ( 2 a : X = Cl, 2 b : X = Br, 2 c : X = I; S‐Alkyne = 3,3,6,6‐tetramethyl‐1‐thiacyclohept‐4‐yne; n = 2, ∞) add the phosphanes PMe3 and Ph2PCH2CH2PPh2 (dppe) to form the mono‐ and dinuclear copper compounds [(S‐Alkyne)CuX(PMe3)] ( 6 ) ( 6 a : X = Cl, 6 b : X = Br) and [(S‐Alkyne)CuX(μ‐dppe)CuX(S‐Alkyne)] ( 7 a : X = Cl, 7 b : X = Br, 7 c : X = I), respectively. By‐product in the reaction of 2 a with dppe is the tetranuclear complex [(S‐Alkyne)Cu(μ‐X)2Cu(μ‐dppe)2Cu(μ‐X)2Cu(S‐Alkyne)] ( 8 ). In case of the compounds 7 prolonged reaction times yield the alkyne‐free dinuclear copper complexes [Cu2X2(dppe)3] ( 9 ) ( 9 a : X = Cl, 9 b : X = Br, 9 c : X = I)). X‐ray diffraction studies were carried out with the new compounds 6 a , 6 b , 7 b , 8 , and 9 c .  相似文献   

14.
《Polyhedron》1999,18(8-9):1141-1145
Exchange reactions of trans-[PdXPh(SbPh3)2] (1) (X=Cl or Br) with ligands L in refluxing dichloromethane give the palladium phenyl complexes [PdXPhL2] (X=Cl, L=PPh3, AsPh3, L2=2,2′-bipyridine (bipy), 4,4′-dimethyl-2,2′-bipyridine (dmbipy), 1,10-phenanthroline (phen); X=Br, L=PPh3, L2=bipy). Treatment of the complexes with bis(diphenylphosphino)methane (dppm) in refluxing dichloromethane gives [PdXPh(dppm]2. These complexes have been characterised by microanalysis, IR and 1H NMR spectroscopic data together with single crystal X-ray determinations of the phenyl palladium complexes, trans-[PdClPh(PPh3)2], [PdClPh(bipy)], [PdClPh(dppm)]2, and [PdBrPh(dppm)]2.  相似文献   

15.
New hexa‐coordinated ruthenium (III) complexes of the type [RuX(EPh3)2(L)] (X = Cl or Br; L = dibasic tridentate Schiff base ligand; E = P or As) have been synthesized by the reactions of [RuCl3(PPh3)3], [RuCl3(AsPh3)3] or [RuBr3(AsPh3)3] with the appropriate Schiff base ligands derived by the condensation of salicylaldehyde and 2‐hydroxy‐1‐naphthaldehyde with N(4) substituted thiosemicarbazones. All the new complexes were characterized using various physico‐chemical methods such as elemental analyses, infrared, electron paramagnetic resonance (EPR) spectroscopy, magnetic moment and cyclic voltammetry. Based on the extended X‐ray absorption fine structure (EXAFS) analysis, an octahedral structure has been confirmed for the complexes. The new complexes have been subjected to the catalytic activity and antibacterial studies. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

16.
Several palladium(II) and platinum(II) complexes of tripropylarsanes (AsR3; R = Pr, iPr) with the formulae, [MCl2(AsR3)2], [M2Cl2(μ‐Cl)2(AsR3)2], [Pd2Me2(μ‐Cl)2(AsR3)2], [Pd2X2(μ‐Pz)2(AsR3)2] (X = Cl or Me, Pz = pyrazolate), [Pd2Cl2(μ‐Y)2(AsR3)2] (Y = OAc or SPh), [MCl(S2CNEt2)(AsR3)] and [PdCp(Cl)(AsiPr3)] (M = Pd or Pt) have been prepared. All the complexes have been characterised by elemental analyses, IR and 1H NMR spectroscopy. The stereochemistry of the complexes has been deduced from the spectroscopic data. The structures of [Pd2Me2(μ‐X)2(AsiPr3)2] (X = Cl or Pz) have been established by single crystal X‐ray diffraction analyses. Both of the complexes have sym‐trans configuration. Strong trans influence of the methyl group is reflected on the Pd—X bond distances.  相似文献   

17.
Pincer‐type palladium complexes are among the most active Heck catalysts. Due to their exceptionally high thermal stability and the fact that they contain PdII centers, controversial PdII/PdIV cycles have been often proposed as potential catalytic mechanisms. However, pincer‐type PdIV intermediates have never been experimentally observed, and computational studies to support the proposed PdII/PdIV mechanisms with pincer‐type catalysts have never been carried out. In this computational study the feasibility of potential catalytic cycles involving PdIV intermediates was explored. Density functional calculations were performed on experimentally applied aminophosphine‐, phosphine‐, and phosphite‐based pincer‐type Heck catalysts with styrene and phenyl bromide as substrates and (E)‐stilbene as coupling product. The potential‐energy surfaces were calculated in dimethylformamide (DMF) as solvent and demonstrate that PdII/PdIV mechanisms are thermally accessible and thus a true alternative to formation of palladium nanoparticles. Initial reaction steps of the lowest energy path of the catalytic cycle of the Heck reaction include dissociation of the chloride ligands from the neutral pincer complexes [{2,6‐C6H3(XPR2)2}Pd(Cl)] [X=NH, R=piperidinyl ( 1 a ); X=O, R=piperidinyl ( 1 b ); X=O, R=iPr ( 1 c ); X=CH2, R=iPr ( 1 d )] to yield cationic, three‐coordinate, T‐shaped 14e? palladium intermediates of type [{2,6‐C6H3(XPR2)2}Pd]+ ( 2 ). An alternative reaction path to generate complexes of type 2 (relevant for electron‐poor pincer complexes) includes initial coordination of styrene to 1 to yield styrene adducts [{2,6‐C6H3(XPR2)2}Pd(Cl)(CH2?CHPh)] ( 4 ) and consecutive dissociation of the chloride ligand to yield cationic square‐planar styrene complexes [{2,6‐C6H3(XPR2)2}Pd(CH2?CHPh)]+ ( 6 ) and styrene. Cationic styrene adducts of type 6 were additionally found to be the resting states of the catalytic reaction. However, oxidative addition of phenyl bromide to 2 result in pentacoordinate PdIV complexes of type [{2,6‐C6H3(XPR2)2}Pd(Br)(C6H5)]+ ( 11 ), which subsequently coordinate styrene (in trans position relative to the phenyl unit of the pincer cores) to yield hexacoordinate phenyl styrene complexes [{2,6‐C6H3(XPR2)2}Pd(Br)(C6H5)(CH2?CHPh)]+ ( 12 ). Migration of the phenyl ligand to the olefinic bond gives cationic, pentacoordinate phenylethenyl complexes [{2,6‐C6H3(XPR2)2}Pd(Br)(CHPhCH2Ph)]+ ( 13 ). Subsequent β‐hydride elimination induces direct HBr liberation to yield cationic, square‐planar (E)‐stilbene complexes with general formula [{2,6‐C6H3(XPR2)2}Pd(CHPh?CHPh)]+ ( 14 ). Subsequent liberation of (E)‐stilbene closes the catalytic cycle.  相似文献   

18.
New ruthenium(III) complexes of the [RuY(LL)(E)2] type (Y = Cl or Br; LL = tridentate Schiff bases; E = PPh3 or AsPh3) have been synthesised by reacting [RuX3(EPh3)3] (X = Cl, E = P; X = Cl or Br, E = As) or [RuBr3(EPh3)2(MeOH)] with Schiff bases having the donor groups (O, N, X) viz., salicylaldehydethiosemicarbazone (X = S), salicylaldehydesemicarbazone (X = O), o-hydroxyacetophenonethiosemicarbazone (X = S) and o-hydroxyacetophenonesemicarbazone (X = O). The new complexes were characterised by elemental analysis, spectral (i.r., electronic spectra, e.p.r.), magnetic moment and cyclic voltammetry data. Biocidal activity studies were also carried out for the new complexes.  相似文献   

19.
β-Substituted σ-vinylpalladium complexes [Pd(σ-CHCHCOOR)(PPh3)2(X)] (I) (X = Cl, I; R = Me, Et) have been obtained by interaction of the E- and Z-β-halogen acrylates with tetrakis(triphenylphosphine)palladium. On heating complexes I rearrange into isomeric η2-olefin-ylidepalladium complexes [PdCH(COOR)-CHPPh3(PPh3)(X)] (II). The structure of these com X-ray study of the compound with X = I, R = Me.  相似文献   

20.
The nickel(II) N‐benzyl‐N‐methyldithiocarbamato (BzMedtc) complexes [Ni(BzMedtc)(PPh3)Cl] ( 1 ), [Ni(BzMedtc)(PPh3)Br] ( 2 ), [Ni(BzMedtc)(PPh3)I] ( 3 ), and [Ni(BzMedtc)(PPh3)(NCS)] ( 4 ) were synthesized using the reaction of [Ni(BzMedtc)2] and [NiX2(PPh3)2] (X = Cl, Br, I and NCS). Subsequently, complex 1 was used for the preparation of [Ni(BzMedtc)(PPh3)2]ClO4 ( 5 ), [Ni(BzMedtc)(PPh3)2]BPh4 ( 6 ), and [Ni(BzMedtc)(PPh3)2]PF6 ( 7 ). The obtained complexes 1 – 7 were characterized by elemental analysis, thermal analysis and spectroscopic methods (IR, UV/Vis, 31P{1H} NMR). The results of the magnetochemical and molar conductivity measurements proved the complexes as diamagnetic non‐electrolytes ( 1 – 4 ) or 1:1 electrolytes ( 5 – 7 ). The molecular structures of 4 and 5· H2O were determined by a single‐crystal X‐ray analysis. In all cases, the NiII atom is tetracoordinated in a distorted square‐planar arrangement with the S2PX, and S2P2 donor set, respectively. The catalytic influence of selected complexes 1 , 3 , 5 , and 6 on graphite oxidation was studied. The results clearly indicated that the presence of the products of thermal degradation processes of the mentioned complexes has impact on the course of graphite oxidation. A decrease in the oxidation start temperatures by about 60–100 °C was observed in the cases of all the tested complexes in comparison with pure graphite.  相似文献   

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