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1.
The reactions of the substituted Group VI metal carbonyls of the type M(CO)4(2-Mepy)2 (M = Mo, w) and M(CO)3(L)3 (L = py, M = Mo, W; L = NH3, M = Mo) with mercuric derivatives HgX2 (X = Cl, CN, SCN) have given rise to three series of tricarbonyl complexes: M(CO)3(py)HgCl2 · 1/2HgCl2 (M = Mo, W); 2[M(CO)3(L)]Hg(CN)·nHg(CN)x (L = py, M = Mo, W, n = 12, × = 2; L = 2- Mepy, × = 1; M = Mo, n = 3; M = W, n = 1); and [M(CO)3(L)Hg(SCN)2 · nHg(SCN)2] (L = py, M = Mo,W, n = 0; L = 2-Mepy, M = Mo, W, n = 12; L = NH3, M = Mo, n = 0) depending on which mercuric compound is employed. All the reactions with Hg(SCN)2 give isolable products whereas those with Hg(CN)2 and HgCl2 did so far only the reactions with [M(CO)4(2-Mepy)2] and M(CO)3(py)3. The greater reactivity of Hg(SCN)2 than of Hg(CN)2 and HgCl2 is consistent with the various acceptor capacities of the groups bonded to the mercury atom.The reactions studied always involve displacement of the N-donor ligand of the original complex and partial or total displacement of the halide or pseudohalide groups of the mercury compound to give in all cases compounds containing MHg bonds. In addition, elimination of a CO group in the tetracarbonyl complexes M(CO)4(2-Mepy)2occurs.  相似文献   

2.
Direct measurement of the enthalpy of decomposition of HCr(CO)3C5H5 to [Cr(CO)3C5H5]2 and H2 was made by differential scanning calorimetry. The heat of hydrogenation of 1,3-cyclohexadiene by HM(CO)3C5H5 for M = Cr, Mo, and W was measured by solution calorimetry. The enthalpies of iodination of [M(CO)3C5H5]2 and HM(CO)3C5H5 were measured for M = Mo and W. These data have been used to calculate the heats of hydrogenation for each of the metal—metal bonded dimers, [M(CO)3C5H5]2 (M = Cr, Mo, and W).C5H5(CO)3M-M(CO)3C5H5(s) + H2(g) → 2HM(CO)3C5H5(s)Addition of hydrogen has been found to be exothermic for M = Cr, W (?3.3 kcal/mol and ?1.5 kcal/mole, respectively) but endothermic for M = Mo (+6.3 kcal/mol). These results are consistent with the trend of increasing MH bond strengths upon descending Group VI. Addition of H2 to [Cr(CO)3C5H5]2 is favored by the unusually weak chromium—chromium bond.  相似文献   

3.
The infrared spectra of M(CO)5(MCH) (MCH = methylcyclohexane; M = Cr, Mo, W), formed by 366 nm irradiation of M(CO)6 at ?78°C in rigorously purified methylcyclohexane, are reported. The previously reported spectrum of “W(CO)5” at low temperature in methylcyclohexane/isopentane solution is attributed to W(CO)5(impurity), where the impurity is probably an aromatic or olefinic hydrocarbon. Spectra in methylene chloride solution are also discussed. The photochemical reactions of W(CO)6 with aromatic hydrocarbon ligands in methylcyclohexane solution were also studied at ?78°C in a low temperature infrared cell. Irradiation (366 nm) of W(CO)6 at ?78°C in rigorously purified methylcyclohexane solution containing approximately 5% (v/v) toluene, benzene, mesitylene, biphenyl, or p-xylene initially produces the complex W(CO)5? (MCH). In the presence of the aromatic hydrocarbon, this complex is unstable and it decomposes in a dark reaction to give a complex which has an infrared spectrum typical for a C4v M(CO)5X molecule. It is proposed that the product of the dark reaction is W(CO)5(aromatic), formed by reaction of W(CO)5(MCH) with the aromatic ligand in solution. The infrared spectra of the W(CO)5? (aromatic) complexes are different from the spectra previously reported for these complexes. It is shown that the spectra previously reported for W(CO)5? (aromatic) are actually attributable to W(CO)5(hexane) (hexane was the solvent used in the previous study); these spectra were probably obtained before W(CO)5(hexane) had time to react with the aromatic hydrocarbon.  相似文献   

4.
Coordination of various neutral N and O ligands causes drastic changes in 1J(31P-199Hg) (increase up to the threefold) and δ(31P) (shifts up to 30 ppm to low frequencies), which are due to the presence of the M(CO)5 groups. The complexes with DMSO, phen and bipy were isolated in the solid state. No coordination of [Hg{PCy2[Cr(CO)5]}2] with the above ligands is observed.  相似文献   

5.
Blocking of the lone pair of electrons on the nitrogen in azaferrocene by co-ordination to the W(CO)5 moiety enables Friedel-Crafts acylation of this heteroferrocene. W(CO)5-complexes of azaferrocene and 2,5-dimethylazaferrocene react with acetyl- and propionyl chloride or acetic anhydride in the presence of aluminium chloride in dichloromethane at r.t. to give W(CO)5-complexes of 1′-acylazaferrocenes in 10-50% isolated yields. The low yields presumably result from instability of the products in the reaction medium. The X-ray structure of the complex of 1′-acetylazaferrocene has been determined.  相似文献   

6.
The reaction between Cr(CO)5[C6H6] and ethyl diazoacetate (EDA) has been studied using the technique of laser flash photolysis. Results indicate that the Cr(CO)5 fragment reacts very rapidly with the EDA ligand. Low temperature spectroscopic studies suggest that in the case of W(CO)5, and by analogy also in the case of Cr(CO)5, the initial adduct between the pentacarbonyl fragment and EDA is one where the oxygen atom of the diazocarbonyl ligand is bound to the metal center. This kinetic product is then converted to a thermodynamically favored complex which is tentatively assigned as the nitrogen bound W(CO)5-EDA complex that appears to be stable at r.t.  相似文献   

7.
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   

8.
Three new uranyl tungstates, A8[(UO2)4(WO4)4(WO5)2] (A=Rb (1), Cs (2)), and Rb6[(UO2)2O(WO4)4] (3), were prepared by high-temperature solid-state reactions and their structures were solved by direct methods on twinned crystals, refined to R1=0.050, 0.042, and 0.052 for 1, 2, and 3, respectively. Compounds 1 and 2 are isostructural, monoclinic P21/n, (1): a=11.100(7), b=13.161(9), , β=90.033(13)°, , Z=8 and (2): , , , β=89.988(2)°, , Z=8. There are four symmetrically independent U6+ sites that form linear uranyl [O=U=O]2+ cations with rather distorted coordination in their equatorial planes. There are six W positions: W(1) and W(2) have square-pyramidal coordination (WO5), whereas W(3), W(4), W(5), and W(6) are tetrahedrally coordinated. The structures are based upon a novel type of one-dimensional (1D) [(UO2)4(WO4)4(WO5)2]4− chains, consisting of WU4O25 pentamers linked by WO4 tetrahedra and WO5 square pyramids. The chains run parallel to the a-axis and are arranged in modulated pseudo-2D-layers parallel to (0 1 0). The A+ cations are in the interlayer space between adjacent pseudo-layers and provide a 3D integrity of the structures. Compounds 1 and 2 are the first uranyl tungstates with 2/3 of W atoms in tetrahedral coordination. Such a high concentration of low-coordinated W6+ cations is probably responsible for the 1D character of the uranyl tungstate units. The compound 3 is triclinic, Pa=10.188(2), b=13.110(2), , α=97.853(3), β=96.573(3), γ=103.894(3)°, , Z=4. There are four U positions in the structure with a typical coordination of a pentagonal bipyramid that contain uranyl ions, UO22+, as apical axes. Among eight W sites, the W(1), W(2), W(3), W(4), W(5), and W(6) atoms are tetrahedrally coordinated, whereas the W(7) and W(8) cations have distorted fivefold coordination. The structure contains chains of composition [(UO2)2O(WO4)4]6− composed of UO7 pentagonal bipyramids and W polyhedra. The chains involve dimers of UO7 pentagonal bipyramids that share common O atoms. The dimers are linked into chains by sharing corners with WO4 tetrahedra. The chains are parallel to [−101] and are arranged in layers that are parallel to (1 1 1). The Rb+ cations provide linkage of the chains into a 3D structure. The compound 1 has many structural and chemical similarities to its molybdate analog, Rb6[(UO2)2O(MoO4)4]. However, the compounds are not isostructural. Due to the tendency of the W6+ cations to have higher-than-fourfold coordination, part of the W sites adopt distorted fivefold coordination, whereas all Mo atoms in the Mo compound are tetrahedrally coordinated. Distribution of the WO5 configurations along the chain extension does not conform to its ‘typical’ periodicity. As a result, both the chain identity period and the unit-cell volume are doubled in comparison to the Mo analog, which leads to a new structure type.  相似文献   

9.
Crystals of NaMg3Al(MoO4)5 doped with 0.5% Cr3+ ions have been synthesized and characterized by a single-crystal X-ray structure analysis and IR, Raman, electron absorption and luminescence spectroscopic studies. It has been shown that NaMg3Al(MoO4)5 crystallizes in the structure, with a=6.8744(8) Å, b=6.9342(7) Å, c=17.605(2) Å, α=87.788(8)°, β=87.727(9)°, γ=78.501(9)°, Z=2. The characteristic feature of the structure is its enormously large thermal displacement parameter for sodium, even at 105 K. The IR and Raman spectra indicate significant interactions between the MoO42− ions in the structure. The electron absorption, excitation and luminescence studies have shown that there are at least two different sites of incorporated Cr3+ ions in the NaMg3Al(MoO4)5 crystal structure. They differ themselves by strength of crystalline field. One of them is characterized by Cr3+ in low ligand field and 4T24A2 emission whereas the second is characterized by higher strength of the crystal field and dominant 2E4A2 emission. Temperature-dependent studies show that the compound does not exhibit any phase transition.  相似文献   

10.
Hg(AuF6)2 crystallizes at 200 K in the orthorhombic space group Pbcn (No. 60) with a = 917.67(7) pm, b = 971.59(8) pm, c = 962.04(8) pm, and Z = 4. Mercury atoms are coordinated by eight fluorine atoms with six short and two long Hg-F contacts. HgF8 polyhedra share their four vertices and two edges with six AuF6 units forming a tridimensional framework.The results of X-ray diffraction analysis on single crystals of AgFAuF6 are in agreement with previously known powder X-ray diffraction data (Casteel et al, J. Solid State Chem. 96 (1992) 84-96). AgFAuF6 crystallizes orthorhombic in the space group Pnma (No. 62), a = 717.06(7) pm, b = 761.67(7) pm, c = 1013.61(10) pm at 200 K, Z = 4.  相似文献   

11.
Bis(4-dimethylaminopyridine) group 12 trifluoroacetates—M(OCOCF3)2·2DMAP (M=Zn, Cd, Hg) were prepared in quantitative yields from the anhydrous metal trifluoroacetates and DMAP. All compounds crystallize in the triclinic space group (no. 2) with two molecules per unit cell. While Zn(OCOCF3)2·2DMAP is built up by well-separated tetrahedral units exhibiting strongly covalent ZnO bonds to monodentate trifluoroactate groups, Cd(OCOCF3)2·2DMAP and Hg(OCOCF3)2·2DMAP form dimeric units. The metal centers are distorted octahedrally surrounded by two axial DMAP ligands, two ionic bridging and one chelating trifluoroacetate group.  相似文献   

12.
The synthesis and properties of heterobimetallic Ti-M complexes of type {[[Ti](μ-η12-CCSiMe3)][M(μ-η12-CCSiMe3)(CO)4]} (M = Mo: 5, [Ti] = (η5-C5H5)2Ti; 6, [Ti] = (η5-C5H4SiMe3)2Ti; M = W: 7, [Ti] = (η5-C5H5)2Ti; 8, [Ti] = (η5-C5H4SiMe3)2Ti) and {[Ti](μ-η12-CCSiMe3)2}MO2 (M = Mo: 13, [Ti] = (η5-C5H5)2Ti; 14, [Ti] = (η5-C5H4SiMe3)2Ti). M = W: 15, [Ti] = (η5-C5H5)2Ti; 16, [Ti] = (η5-C5H4SiMe3)2Ti) are reported. Compounds 5-8 were accessible by treatment of [Ti](CCSiMe3)2 (1, [Ti] = (η5-C5H5)2Ti; 2, [Ti] = (η5-C5H4SiMe3)2Ti) with [M(CO)5(thf)] (3, M = Mo; 4, M = W) or [M(CO)4(nbd)] (9, M = Mo; 10, M = W; nbd = bicyclo[2.2.1]hepta-2,5-diene), while 13-16 could be obtained either by the subsequent reaction of 1 and 2 with [M(CO)3(MeCN)3] (11, M = Mo; 12, M = W) and oxygen, or directly by oxidation of 5-8 with air. A mechanism for the formation of 5-8 is postulated based on the in-situ generation of [Ti](CCSiMe3)((η2-CCSiMe3)M(CO)5), {[Ti](μ-η12-CCSiMe3)2}-M(CO)4, and [Ti](μ-η12-CCSiMe3)((μ-CCSiMe3)M(CO)4) as a result of the chelating effect exerted by the bis(alkynyl) titanocene fragment and the steric constraints imposed by the M(CO)4 entity.The molecular structure of 5 in the solid state were determined by single crystal X-ray diffraction analysis. In doubly alkynyl-bridged 5 the alkynides are bridging the metals Ti and Mo as a σ-donor to one metal and as a π-donor to the other with the [Ti](CCSiMe3)2Mo core being planar.  相似文献   

13.
The reaction of sodium cyanopentacarbonylmetalates Na[M(CO)5(CN)] (M=Cr; Mo; W) with cationic Fe(II) complexes [Cp(CO)(L)Fe(thf)][O3SCF3], [L=PPh3 (1a), CN-Benzyl (1b), CN-2,6-Me2C6H3 (1c); CN-But (1d), P(OMe)3 (1e), P(Me)2Ph (1f)] in acetonitrile solution, yielded the metathesis products [Cp(CO)(L)Fe(NCCH3)][NCM(CO)5] [M=W, L=PPh3 (2a), CN-Benzyl (2b), CN-2,6-Me2C6H3 (2c); CN-But (2d), P(OMe)3 (2e), P(Me)2Ph (2f); M=Cr, L=(PPh3) (3a), CN-2,6-Me2C6H3 (3c); M=Mo, L=(PPh3) (4a), CN-2,6-Me2C6H3 (4c)]. The ionic nature of such complexes was suggested by conductivity measurements and their main structural features were determined by X-ray diffraction studies. Well-resolved signals relative to the [M(CO)5(CN)] moieties could be distinguished only when 13C NMR experiments were performed at low temperature (from −30 to −50 °C), as in the case of [Cp(CO)(PPh3)Fe(NCCH3)][NCW(CO)5] (2a) and [Cp(CO)(Benzyl-NC)Fe(NCCH3)][NCW(CO)5] (2b). When the same reaction was carried out in dichloromethane solution, neutral cyanide-bridged dinuclear complexes [Cp(CO)(L)FeNCM(CO)5] [M=W, L=PPh3 (5a), CN-Benzyl (5b); M=Cr, L=(PPh3) (6a), CN-2,6-Me2C6H3 (6c), CO (6g); M=Mo, L=CN-2,6-Me2C6H3 (7c), CO (7g)] were obtained and characterized by infrared and NMR spectroscopy. In all cases, the room temperature 13C NMR measurements showed no broadening of cyano pentacarbonyl signals and, relative to tungsten complexes [Cp(CO)(PPh3)FeNCW(CO)5] (5a) and [Cp(CO)(CN-Benzyl)FeNCW(CO)5] (5b), the presence of 183W satellites of the 13CN resonances (JCW ∼ 95 Hz) at room temperature confirmed the formation of stable neutral species. The main 13C NMR spectroscopic properties of the latter compounds were compared to those of the linkage isomers [Cp(CO)(PPh3)FeCNW(CO)5] (8a) and [Cp(CO)(CN-Benzyl)FeCNW(CO)5] (8b). The characterization of the isomeric couples 5a-8a and 5b-8b was completed by the analyses of their main IR spectroscopic properties. The crystal structures determined for 2a, 5a, 8a and 8b allowed to investigate the geometrical and electronic differences between such complexes. Finally, the study was completed by extended Hückel calculations of the charge distribution among the relevant atoms for complexes 2a, 5a and 8a.  相似文献   

14.
许多化学工作者对单齿膦配体(PPh3,PBun3,PEt2Ph,P(OEt)3,P(OC6H5)3)与母体簇合物FeCo2(CO)9(μ3-S)的取代反应进行过详细研究[1-3],但对双齿膦配体与母体簇合物的取代反应研究报导较少.Aime[4]合成了含双齿膦配体的簇合物FeCo2(CO)7(μ3-S)(Ph2PCH2PPh2),并用13CNMR和IR光谱方法对其结构进行了表征.到目前为止,含双齿膦配体的该类簇合物的晶体与分子结构还未见报导.RosannaRossetti[2]通过研究母体簇合物与…  相似文献   

15.
Rh2(μ-SC6H5)2(CO)4的合成和晶体结构   总被引:2,自引:0,他引:2  
一种路易斯碱,例如膦(PR3)或异氰化物(CNR)加到双核或多核络合物中,会导致低核物种的形成,这就伴随有金属一金属键的断裂[1].这样的例子很多,如我们曾用F33(CO)12与P(SC6H5)3反应,分离出三个不同的两核铁数合物[2].现在我们报导另一个例子:用Rh4(CO)12与P(SC6H小反应,同样也得到一个两核物种WhZ(P-SC6H巾(C)4.该化合物首先由B0ltoll*等人用WhZ(CO)ZC12与苯硫酚C6H。SH反应得到,但有关它的X-rar晶体结构的测定还未见报导·与之相似的化合物Rh。(p-SC。H。F)。门O)。的结构已由ClaverN…  相似文献   

16.
Complete geometry optimizations were carried out by HF and DFT methods to study the molecular structure of binuclear transition-metal compounds (Cp(CO)3W(μ-PPh2)W(CO)5) (I) and (Cp(CO)2W(μ-PPh2)W(CO)5) (II). A comparison of the experimental data and calculated structural parameters demonstrates that the most accurate geometry parameters are predicted by the MPW1PW91/LANL2DZ among the three DFT methods. Topological properties of molecular charge distributions were analyzed with the theory of atoms in molecules. (3, −1) critical points, namely bond critical point, were found between the two tungsten atoms, and between W1 and C10 in complex II, which confirms the existence of the metal–metal bond and a semi-bridging CO between the two tungsten atoms. The result provided a theoretical guidance of detailed study on the binuclear phosphido-bridged complex containing transition metal–metal bond, which could be useful in the further study of the heterobimetallic phosphido-bridged complexes.  相似文献   

17.
Convenient synthetic route to prepare the germylene complexes of tungsten pentacarbonyls, W(CO)5GeCl2 and W(CO)5GeW(CO)5, electrochemically is developed. Combined quantum-chemical/IR spectroscopic approach is used for identification of the synthesized compounds. Good agreement between theoretical and experimental spectra can be regarded as one of the proofs of their supposed structures.  相似文献   

18.
A novel complex containing a (μ-bicarbonato)-bis(μ-hydroxo)dicobalt(II) cation and a (μ-cyano)dichromium(III) anion has been obtained and characterized by single crystal X-ray diffraction. The cations have a confacial bioctahedral structure and the anion contains an octahedral Cr(CN)63− unit bridging to the second Cr which has trigomal planar geometry.  相似文献   

19.
The (NH4)0.80Li0.20[Fe(AsO4)F] compound has been synthesized under mild hydrothermal conditions. The compound crystallize in the orthorhombic Pna21 space group, with cell parameters a=13.352(9), b=6.7049(9), c=10.943(2) Å and Z=8. The compound belongs to the KTiO(PO4) structure type, with chains alternating FeO4F2 octahedra and AsO4 tetrahedra, respectively, running along the “a” and “b” crystallographic axes. The diffuse reflectance spectrum in the visible region shows the forbidden electronic transitions characteristic of the Fe(III) d5-high spin cation in slightly distorted octahedral geometry. The Mössbauer spectrum at room temperature is characteristic of iron (III) cations. The ESR spectra, carried out from room temperature to 200 K, remain isotropic with variation in temperature; the g-value being 1.99(1). Magnetic measurements indicate the predominance of strong antiferromagnetic interactions.  相似文献   

20.
Photolysis of a hexane solution containing ironpentacarbonyl, 1-ferrocenyl-4-phenyl-1,3-butadiyne at low temperature yields six new products: [Fe(CO)222-PhCCCC(Fc)C(CCPh)C(Fc)Fe(CO)3}-μ-CO] (1), [Fe2(CO)6{μ-η1122-PhCCCC(Fc)-C(O)-C(Fc)CCCPh}] (2), [Fe2(CO)6{μ-η1122-FcCC(CC Ph)-C(O)-C(Fc)CCCPh}] (3), [Fe2(CO)6{μ-η1122-FcCCCC(Fc)-C(O)-C(Fc)CCCPh}] (4), [Fe(CO)3{μ-η2: η2-[FcCC(CCPh)C(CCPh)C(Fc)}CO] (5) and [Fe(CO)3{μ-η2: η2-[FcCC(CCPh)C(CCPh)C(Fc)}CO] (6) formed by coupling of acetylenic moieties with CO insertion on metal carbonyl support. In presence of CO, formation of another new product 2,5-bis(ferrocenyl)-3,6-bis(tetracarbonylphenylmaleoyliron)quinone (7) was observed which on further reaction with ferrocenylacetyene gave the quinone, 2,5-bis(ferrocenyl)-3,6-bis(ethynylphenyl)quinone (8). Structures of 1-5 and 8 were established crystallographically.  相似文献   

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