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1.
Pentacarbonyl(diethylaminocarbyne)chromium tetrafluoroborate, [(CO)5− CrCNEt2]BF4 (I), reacts with PPh3 with substitution of CO and formation of trans-tetracarbonyl(diethylaminocarbyne)triphenylphosphanechromium tetra-fluoroborate, trans-[PPh3(CO)4CrCNEt2]BF4 (III). Substitution of CO by PPh3 in neutral trans-tetracarbonyl(halo)(diethylaminocarbyne)chromium complexes, trans-X(CO)4CrCNEt2 (IVa: X = Br, IVb: X = I), leads in a reversible reaction to the corresponding tricarbonyl complexes, mer-X(PPh3)(CO)3− CrNEt2 (V), PPh3 occupying the cis-position to the carbyne ligand. With PPh3 in large excess both reactions follow a first-order rate law. This as well as the activation parameters (ΔH≠ = 104–113 kJ mol−1, ΔS≠ = 64–71 J mol−1 K−1) indicate a dissociative mechanism.  相似文献   

2.
In the reaction of cis-(CO)4(SnPh3)Re[C(OEt)NR2] (R = ipr (isopropyl), chex (cyclohexyl)) with BI3 the Lewis acid attacks the triphenylstannyl ligand. Substitution of a phenyl for a iodine group leads to equilibrium mixtures of rhenium carbene complexes of general formula cis-(CO)4(SnPh3−χIχ)Re[C(OEt)NR2] (χ = 1−3; R = ipr, chex). By changing the solvent and ratio of can be shifted such that only one major product is formed. Thus this reaction pathway can be used for the preparation of cis-(CO)4(SnPhI2)Re[C(OEt)NR2] (R = ipr, chex). Even when a large excess of BI3 is present electrophilic attack by the Lewis acid on the carbene ligand is not observed.

Synthesis of cis-(CO)4(SnPh3−χIχ)Re[C(OEt)NR2] (χ = 1−3; R --- ipr, chex) can be achieved in high yield by reaction of cis-(CO)4(SnPh3)Re[C(OEt)NR2] (R = ipr, chex) with one, two or three equivalents of HI. This reaction, with successive rupture of the tin-carbon bonds in the triphenylstannyl ligand and the simultaneous formation of benzene, affords the desired substitution product irreversibly. Reaction of cis-(CO)4(SnPh3)Re[C(OEt)NR2] (R = ipr, chex) with I2 gives the compounds, cis-(CO)4(SnI3)Re[C(OEt)NR2] (R = ipr, chex), in relatively low yields.  相似文献   


3.
The aryldiazenido ligands provide the fourth member of the isoelectronic series CO, NO+, RNC, RN2+ of ligands for transition metal complexes. The first aryldiazenido metal complex was reported in 1964 when p-CH3OC6H4N2Mo(CO)2C5H5 was prepared by the reaction of NaMo(CO)3C5H5 with p-CH3OC6H4N2+BF4. This review surveys the development of organometallic aryldiazenido chemistry since that time. Such organometallic aryldiazenido derivatives, including RN2M(CO)2C5H5, RN2M(CO)2(Pz3BH) (M = Cr, Mo, W), [(η6-Me6C6)Cr(CO)2N2Ar]+, [(MeC15H4)M′(CO)2N2Ar]+ M′ = Mn, Re), [trans-PhN2Fe(CO)2(PPh3)2]+, and PhN2M′(CO)2(PPh3)2(PPh3)2 can be obtained by reactions of arenediazonium salts with suitably chosen transition metal nucleophiles. Analogous methods cannot be used to prepare alkyldiazenido transition metal complexes because of the instability of alkyldiazonium salts. However, the alkyldiazenido derivatives RCH2N2M(CO)2C5H5 (R = H or Me3Si) can be obtained from HM(CO)3C5H5 and the corresponding diazoalkanes. Important aspects of the chemical reactivity of RN2M(CO)2Q derivatives (Q = C5H5, Pz3BH) include CO substitution reactions, coordination of the second nitrogen in the RN2 ligand to give heterobimetallic complexes such as C5H5Mo(CO)2(μ-NNC6H4Me)(CO)2C5H5, oxidative addition rections with X2 X = Cl, Br, I), SnX4, RSSR, and CINO, and reactions with further RN2+ to give bis(aryldiazenido) derivatives (RN2)2MQL+ (L = CO, X, etc.). Dearylation of an aryldiazenido ligand to a dinitrogen ligand can be effected by reaction of [(MeC5H4)M′(CO)2N2Ar]+ with certain nucleophiles to give (MeC5H4)M′(CO)2N2.  相似文献   

4.
The strong π-acid ligand Ph2PN(iBu)PPh2 reacts with Co2(CO)S (1:1) to give Co2[μ-Ph2PN(iBu)PPh2] (μ-CO)2(CO)4 (1); however, when the ratio is 2:1 a novel species [Co{Ph2PN(iBu)PPh2-P,P′}2(CO)][Co(CO)4] (2) has been obtained. Crystal data for 2: Mr = 1140.83; triclinic, space group P , a = 12.330(2), b = 13.340(2), c = 18.122(3) Å, = 86.63(1), β = 80.75(1), γ = 84.24(1)°, V = 2924 Å3, Z = 2; R = 0.060 for 3711 reflections having I 3σ(I). The results of X-ray diffraction, ESR, variable-temperature magnetic susceptibility, conductivity, and XPS analysis support that the species 2 is a d9-d9 cage molecule-pair. The mechanism for the formation of the species 2 has been investigated initially by 31P NMR.  相似文献   

5.
The preparation and characterisation of three new gold(I) phosphine derivatives of the ferraborane, HFe4(CO)12BH2 are reported. In HFe4(CO)12(AuPPh3)BH (2), the AuPPh3 fragment formally replaces an Fe---H---B bridging hydrogen atom in the parent compound HFe4(CO)12BH2. A comparison between 2 and the structurally characterised di-gold derivative, Fe4(CO)12(AuPPh3)2BH (1) is made to gain insight into the relative site preference for the heavy metal fragments in 1. Preparation of the bis(triethylphosphine)gold(I) derivative of HFe4(CO)12BH2 from the PPN+ salt of its conjugate base illustrates a novel exchange reaction between the PPh3 groups in the PPN+ cation and the initially, gold-associated PEt3 groups. This leads to a distribution of products Fe4(CO)12(AuPR3(AuPR′3BH where R = R′ = Ph (1) or R = R′ = Et (3) or R = Ph and R′ = et (4).  相似文献   

6.
The compounds (π-C5H5)(CO)2LM-X (L = CO, PR3; M = Mo, W; X = BF4, PF6, AsF6, SbF6) react with H2S, p-MeC6H4SH, Ph2S and Ph2SO(L′) to give ionic complexes [(π-C5H5)(CO)2LML′]+ X. Also sulfur-bridged complexes, [(π-C5H5)(CO)3W---SH---W(CO)3(π-C5H5)]+ AsF6 and [(π-C5H5)(CO)3M-μ-S2C=NCH2Ph-M(CO)3(π-C5H5)], have been obtained. Reactions with SO2 and CS2 have been examined.  相似文献   

7.
The reaction of K[ReH6(PPh3)2] with [RhCl(CO)L2] [L= PPh3, 1,2,5-triphenylphosphole (TPP), or P(OMe)3] leads to the new electronically unsaturated heterobimetallic polyhydride complexes [(CO)(PPh3)2HRe(μ-H)3RhL2] in moderate-to-good yields. The structures of these complexes have been established on the basis of spectroscopic data, especially 1H and 31P NMR. The bridging hydride ligands are fluxional but there is either a slow or nonexistent exchange between terminal and bridging hydrides. For L = PPh3 or TPP, protonation with tetrafluoroboric acid affords quantitatively the cationic complexes [(CO)(PPh3)2HRe(μ-H)3RhHL2]+, isolated as the BF4 or the BPh4 salts.  相似文献   

8.
The reaction of K[H6ReL2] with [RuHCl(CO)(PPh3)3−x {P(OPri}3)x](L2 = (PMePh2)2, dppe, (AsPh3)2, or (PPh3)2; x = 0, 1 or 2) leads to [L2(CO)HRe(μ-H)3RuH(PPh3)2−y{P(OPri)3}y] (x = 0 or 1, Y = 0; X = 2, Y = 1(L2 = PPh3)) in a first step. Under the reaction conditions most of these complexes react rapidly with the liberated phosphine giving [L2(CO)Re(μ-H)3Ru(PPh3)3−y- {P(OPri)3}y] (L2 = (PMePh2)2 or dppe, Y = 0; L2 = (PPh3)2, Y = 1) as the only iso complexes. The structure of [(PMePh2)2(CO)Re(μ-H)3Ru(PPh3)3] has been establishedby X-ray structure analysis. The complex [(PPh3)2(CO)Re(μ-H)3Ru(PPh3)2(P(OPri)3)] reacts with molecular hydrogen under pressure to generate [L2(CO)HRe(μ-H)3RuH(PPh3)(P(OPri)3) as the sole product.  相似文献   

9.
The molecular and crystal structure of the nido-6-tungstadecaborane [6,6,6,6-(CO)2(PPh3)2-nido-6-WB9H13] (1) has been determined showing that the tungsten atom is incorporated into the 6-position of a nido 10-vertex (WB9) cage. The tungsten atom has a seven-coordinate capped trigonal prismatic environment and is bonded to two hydrogen and three boron atoms of the {B9H13} cage, in addition to two CO groups and two PPh3 ligands. Variable-temperature (−90°C to +50°C) 31P{1H} NMR spectroscopy of 1 reveals that the exo-polyhedral ligands about the tungsten atom are fluxional with respect to PPh3 site exchange with an activation energy (ΔG‡), at the coalescence temperature (−73°C), of <38 kJ mol−1.  相似文献   

10.
The reaction of [(CO)PPh3)2Re(μ-H)2(μ-NCHPh)Ru(PPh3)2(PhCN)] (2) with HBF4-Me2O generates [(CO)PPh3)2Re(μ- H)2(μ,η12HNCHPh)Ru(PPh3)2(PhCN)][BF4] (3). Monitoring the reaction by NMR spectroscopy shows the intermediate formation of [(CO)(PPh3)2 HRe(μ-H)2(μ-NCHPh)Ru(PPh3)2(PhCN)][BF4] (4). Attempted reduction of the imine ligand by a nucleophile (H or CN) failed, regenerating 2. Under dihydrogen at 50 atm, 3 is slowly transformed into [(CO)(PPh3)2HRe(μ-H)3Ru(PPh3)2(PhCN)][BF4] (5) with liberation of benzyl amine.  相似文献   

11.
Geometrical isomerization of fac-Mo(CO)3L3 (L = P(OPh)3, P(OMe)3, P(OEt)3) to the mer form and that of cis-Mo(CO)4L2 (L = P(OPh)3, P(OMe)3, PPh2(OMe)) to the trans form were observed in CH2Cl2 at room temperature in the presence of a catalytic amount of Me3SiOSO2CF3 (TMSOTf). Crossover experiments suggest that a ligand dissociation is not involved in the isomerization. A catalytic cycle involving an interaction of the silicon atom in Me3Si+ with one oxygen in P(OR)3 ligands has been proposed. The first isolation and the X-ray structure analysis were attained for mer-Mo(CO)3{P(OPh)3}3 through the TSMOTf-assisted isomerization of fac-Mo(CO)3{P(OPh)3}3.  相似文献   

12.
Both [Rh4(CO)12] and [Rh6(CO)16] disproportionate in pyridine to cis-[Rh(CO)2(py)2]+ and [Rh5(CO)13(py)2]. In the same solvent, cis-[Rh(CO)2(py)2]+ is reduced by CO/H2O to [(py)2H][Rh5(CO)13-(py)2], which has been structurally characterized.  相似文献   

13.
The complexes [(η6-arene)Ru=C(OMe)CH2R′)Cl(PR3)]PF6 (R′ = Ph; ARENE = Me4C6H2, iPr3C6H3, Et3C6H3; PR3 = PMe3, PPh3, P(OMe)3) have been made from RuCl2(PR3)(arene) precursors by activation at room temperature of phenylacetylene in methanol containing NaPF6. The complex with R′ = nBu, ARENE = Me4C6H2, and PR3 = PMe3 is similarly formed from hex-1-yne but much more slowly, and a complex of the type [(p-cymene)Ru=C(OMe)CH2R′)Cl(PR3)]+PF6 could be obtained only when the phosphine was the bulky PPh3 (10b). It has been shown that the steric hindrance by both arene and phosphine ligands contributes to the stabilization of the carbeneruthenium complexes.  相似文献   

14.
The generality of a two-electron reduction process involving an mechanism has been established for M3(CO)12 and M3(CO)12n(PPh3)n (M = Ru, Os) clusters in all solvents. Detailed coulometric and spectral studies in CH2Cl2 provide strong evidence for the formation of an ‘opened’ M3(CO)122− species the triangulo radical anions M3(CO)12−· having a half-life of < 10−6 s in CH2Cl2. However, the electrochemical response is sensitive to the presence of water and is concentration dependent. An electrochemical response for “opened” M3(CO)122− is only detected at low concentrations < 5 × 10−4 mol dm−3 and under drybox conditions. The electroactive species ground at higher concentrations and in the presence of water M3(CO)112− and M6(CO)182− were confirmed by a study of the electrochemistry of these anions in CH2Cl2; HM3(CO)11 is not a product. The couple [M6(CO)18]−/2− is chemically reversible under certain conditions but oxidation of HM3(CO)11 is chemically irreversible. Different electrochemical behaviour for Ru3(CO)12 is found when [PPN][X] (X = OAc, Cl) salts are supporting electrolytes. In these solutions formation of the ultimate electroactive species [μ-C(O)XRu3(CO)10] at the electrode is stopped under CO or at low temperatures but Ru3(CO)12−· is still trapped by reversible attack by X presumably as [η1-C(O)XRu3(CO)11]. It is shown that electrode-initiated electron catalysed substitution of M3(CO)12 only takes place on the electrochemical timescale when M = Ru, but it is slow, inefficient and non-selective, whereas BPK-initiated nucleophilic substitution of Ru3(CO)12 is only specific and fast in ether solvents particulary THF. Metal---metal bond cleavage is the most important influence on the rate and specificity of catalytic substitution by electron or [PPN]-initiation. The redox chemistry of M3(CO)12 clusters (M = Fe, Ru, Os) is a consequence of the relative rates of metal---metal bond dissociation, metal-metal bond strength and ligand dissociation and in many aspects resembles their photochemistry.  相似文献   

15.
Reaction of Hg(S7N)2 with cis- PtCl2(PR3)2 (PR3 = PPh3, PPh2Me, PPHMe2, PEt3) in the presence of Na[PF6] gives [Pt(S3N)(PR3)2][PF6] in 32–46% yield. The complexes have been characterized by IR, NMR and microanalyses. The X-ray crystal structures of two examples (PR3 = PPh2Me and PEt3) show that the S3N ligand coordinates in a bidentate fashion via two sulphur atoms.  相似文献   

16.
The preparations and spectroscopic characteristics are reported of a series of (trimethylgermyl)methyl- and (trimethylstannyl)methylplatinum(II) complexes with diene and P-donor ancillary ligands, cis-Pt(CH2GeMe3)2L2 (L = PPh3 or PPh2Me; L2 = dppe or cod) and cis-Pt(CH2SnMe3)2L2 (L = PPh3; L2 =cod). Thermolysis of toluene solutions of cis-Pt(CH2GeMe3)2(PPh3)2 leads to cis-Pt(Me)(CH2GeMe2CH2GeMe3)(PPh3)2 via β-alkyl migration, after (non-rate-limiting) phosphine dissociation. Estimated activation parameters (ΔH298 K = 126 ± 3 kJ mol−1, ΔS = + 17 ± 7 J mol−1 K−1 and hence Δ298 K = 121 ± 5 kJ mol−1) suggest that this system is more migration labile than its silicon analogue, primarily as a result of a lower activation enthalpy. While cis-Pt(CH2GeMe3)2(PPh2Me)2 reacts similarly but less readily, Pt(CH2GeMe3)2(dppe)2 is inert at operable temperatures. Thermolysis of Pt(CH2GeMe3)2(cod) generates 1,1,3,3,-tetramethyldi-1,3-germacyclobutane as the major organogermanium product, while from cis-Pt(CH2SnMe3)2(PPh3)2, 1,1,3,3-tetramethyldi-1,3-stannacyclobutane predominates. Mechanistic implications are discussed.  相似文献   

17.
The study of the reactivity of [Pt2M4(CCR)8] (M=Ag or cu; R=Ph or tBu) towards different neutral and anionic ligands is reported. This study reveals that reactions of the phenylacetylide derivatives [Pt2M4(CCPh)8] with anionic, X (X=Cl or Br) or neutral donors (CNtBu or py) in a molar ratio 1:4 (m/donor ratio 1:1) yield the trinuclear anionic (NBu4)2[{Pt(CCPh)4 (MX)2] (M=Ag or Cu, X =Cl or Br) or neutral [{Pt(CCPh04=sAGL)2] (L=CNtBu or py) complexes, respectively. The crystal structure of (NBu4)2[{Pt(CCPh)4}(CuBr)2](4) shows that the anion is formed by a dianionic Pt(CCPh)4 fragment and two neutral CuBr units joined through bridging alkynyl ligands. All the alkynyl groups are σ bonded to Pt and η2-coordinated to a Cu atom which have an approximately trigonal-planar geometry. By contrast, similar reactions with [Pt2M4(CCtBu)8] (molar ratio M/donor 1:1) afford hexanuclear dianionic (NBu4)2[Pt2M4(CCtBu)8X2] or neutral [Pt2Ag4(CCtBu08Py2]. Only by treatment with a large exces of Br (molar ratio M/Br 1:2) are the trinuclear complexes (NBu4)2[{Pt(CCtBu4 (MBr)2] (M=Ag, Cu) obtained. Attempted preparations of analogous complexes with phosphines (L′=PPh3 or PEt3) by reactions of [Pt2M4(CCR8] with L′ leads to displacement of alkynyl ligands from platinum and formation of neutral mononuclear complexes [trans-Pt(CCR)2L′2].  相似文献   

18.
The compound [RU332- -ampy)(μ3η12-PhC=CHPh)(CO)6(PPh3)2] (1) (ampy = 2-amino-6-methylpyridinate) has been prepared by reaction of [RU3(η-H)(μ32- ampy) (μ,η12-PhC=CHPh)(CO)7(PPh3)] with triphenylphosphine at room temperature. However, the reaction of [RU3(μ-H)(μ3, η2 -ampy)(CO)7(PPh3)2] with diphenylacetylene requires a higher temperature (110°C) and does not give complex 1 but the phenyl derivative [RU332-ampy)(μ,η 12 -PhC=CHPh)(μ,-PPh2)(Ph)(CO)5(PPh3)] (2). The thermolysis of complex 1 (110°C) also gives complex 2 quantitatively. Both 1 and 2 have been characterized by0 X-ray diffraction methods. Complex 1 is a catalyst precursor for the homogeneous hydrogenation of diphenylacetylene to a mixture of cis- and trans -stilbene under mild conditions (80°C, 1 atm. of H2), although progressive deactivation of the catalytic species is observed. The dihydride [RU3(μ-H)232-ampy)(μ,η12- PhC=CHPh)(CO)5(PPh3)2] (3), which has been characterized spectroscopically, is an intermediate in the catalytic hydrogenation reaction.  相似文献   

19.
Addition of 1,4-dithiols to dichloromethane solutions of [PtCl2(P-P)] (P-P = (PPh3)2, Ph2P(CH2)3PPh2, Phd2P(CH2)4PPh2; 1,4-dithiols = HS(CH2)4SH, (−)DIOSH2 (2,3-O-isopropylidene-1,4-dithiol-l-threitol), BINASH2 (1,1′-dinaphthalene-2,2′-dithiol)) in the presence of NEt3 yielded the mononuclear complexes [Pt(1,4-dithiolato)(P-P)]. Related palladium(II) complexes [Pd(dithiolato)(P-P)] (P-P=Ph2P(CH2)3PPh2, Ph2P(CH2)4PPh2; dithiolato = S(CH2)4S, (−)-DIOS) were prepared by the same method. The structure of [Pt((−)DIOS)(PPh3)2] and [Pd(S(CH2)4S)(Ph2P(CH2)3PPh2)] complexes was determined by X-ray diffraction methods. Pt—dithiolato—SnC12 systems are active in the hydroformylation of styrene. At 100 atm and 125°C [Pt(dithiolate)(P-P)]/SnCl2 (Pt:Sn = 20) systems provided aldehyde conversion up to 80%.  相似文献   

20.
Reactions of [C6F5Xe]+ [AsF6] in acetonitrile with halide anions X show different results depending on X. If X = I, Br or Cl, then C6F5X is obtained. If X = F, then C6F5H and C6F5---C6F5 are produced, and if X = HF2, then C6F6, C6F5H and C6F5---C6F5 are formed.  相似文献   

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