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1.
Proton NMR data for the Group III methyl derivatives, MMe3 and LiMMe4 are compared with NMR data for the novel tin—Group III-metal bonded species, Li[Me3SnMMe3] (M Al, Ga, In and Tl) and for Li[(Me3Sn)n-TlMe4?n] (n = 0 to 4), reported here for the first time.The presence of tinmetal bonding in these derivatives is established by the observed tin-across-metal coupling constants and for the thallium derivatives by the additional observation of thallium-across-tin coupling.The variation in the magnitudes of 2J(SnCH), 2J(TlCH), 3J(SnMCH) and 3J(TlSnCH) are reported as a function of M and as a function of the number of Me3Sn groups bond to thallium in the [(Me3Sn)nTIME4?n]?anions. Proposals concerning the factors governing the changes in these coupling constants and the chemical shifts are presented. 相似文献
2.
The reactions of ditungsten hexa-t-butoxide, W2(OCMe3)6, with dicyclohexylcarbodiimide, C6H11NCNC6H11, and diisopropylcarbodiimide, Me2CHNCNCHMe2, afford the 1:1 adducts, [W(OCMe3)3]2(μ-C6H11NCNC6H11), 1, and [W(OCMe3)3]2(μ-C3H7NCNC3H7), 2, respectively. These products were each shown by X-ray crystallography to be structurally homologous to the previously reported [W(OCMe3)3]2(μ-CH3C6H4NCNC6H4CH3) and similar to [W(OCMe3)3(μ-C6H5NCO). It has been shown that the [W(OCMe3)3]2(μ-RNCNR) compounds fail to react with further RNCNR, with PhNCO, PMe3, LiOCMe3 or LiOCHMe2, CO or CO2, and also that [W(OCMe3)3]2(μ-PhNCO) does not afford any defined product when treated with C6H11NCNC6H11. Compounds 1 and 2 were fully characterized by IR and NMR spectroscopy and by X-ray crystallography. Compound 1 crystallizes in space group C2/c with unit cell dimensions a = 13.481(3) Å, b = 18.129(4) Å, c = 18.244(2) Å, β = 97.54(1)°, V = 4420(2) Å3, Z = 4. It was refined to R = 0.0375, Rw = 0.0475. Compound 2 crystallizes in space group P21/c with unit cell dimensions a = 14.752(2) Å, b = 12.157(3) Å, c = 22.189(3) Å, β = 97.03(2)°, V = 3949(2) Å3, Z = 4. The structure was refined to R = 0.053, Rw = 0.059. Each molecule has C2-symmetry, with two W(OCMe3) units united by RNCNR bridges across WW distances of 2.490(1) and 2.485(1) Å for 1 and 2, respectively. 相似文献
3.
From the reactions between 1,4-dilithiobutane and 1,2-M2Cl2(NMe2)4 compounds in hydrocarbon solvents, the 1,2-dimetallacyclo-1,2-hexyne compounds M2(CH2)4(NMe2)4(MM), where M = Mo and W, have been obtained as yellow—orange, volatile microcrystalline compounds. Spectroscopic data are consistent with expectations based on previous studies of gauche 1,2-M2R2(NMe2)4 compounds in solution and a structural model based on the observed molecular structure of 1,2-Mo2Et2(NMe2)4 is presented and compared with the observed molecular structure of Mo2(CH2)4(NMe2)4 found in the solid state. Pertinent bond distances (Å) and angles (°) are: Mo—Mo = 2.200(1), Mo—N = 1.96(1) (averaged), Mo—C = 2.165(8) (averaged), Mo—Mo—N = 105(1), Mo—Mo—C = 97(1). 相似文献
4.
Solubilities and the solvolytic behaviour of various inorganic compounds, Lewis acids and bases in fused monobromoacetic acid at 60 ± 0.5°C are discussed. Ionic compounds are fairly soluble, iodides and thiocyanates being comparatively more soluble than chlorides and bromides. Tetraalkyl ammonium halides are highly soluble in this solvent. Conductometric and spectroscopic studies of various Lewis acids and bases in fused monobromoacetic acid indicate their solvolytic behaviour and their subsequent ionization. The solvolyses products BBr3·CH2BrCOOH and SbCl5·CH2BrCOOH have been observed to be the strongest Bronsted acids. Auto-ionization of this solvent has been supported by acid/base titrations. 相似文献
5.
An attempt was made to estimate the net charges of a number of cyclopentadienyl metal compounds on the basis of 19F NMR data for p-fluorophenylcyclopentadienyl metal compounds. The investigated compounds can be clearly divided into four groups according to the polarity of metal-cyclopentadienyl bond: covalent compounds (derivatives of Fe, Ru, Os, Rh and Pd) with a net charge on the η-C5H5 ring in the range from ?0.19 to ?0.29, the so-called ionic compounds (derivatives of Li, Na and K) with a net charge on the ring ?0.64 ÷ ?0.72, and compounds with an intermediate character of the bond (derivatives of Cu, Mg and T1) with a net charge of ?0.44 ÷ ?0.46; the net charge on the rings of cyclopentadienyl manganese tricarbonyl and -rhenium tricarbonyl is near to zero. When the effective charge on the ring is near ?0.44 the cyclopentadienyl metal compounds are able to dissociate into ions in solution. 相似文献
6.
The action of 1,10-phenanthroline (phen) on the THF solutions of RHgCl (R = 2,5-C6H3Cl2; 2,3,4? and 2,4,6-C6H2Cl3; 2,3,4,5?, 2,3,4,6?, and 2,3,5,6-C4HCl4 and C6Cl5) gives RHgCl (phen) when R contains two chlorine substituents in ortho (R = 2,4,6-C6H2Cl3; 2,3,4,6?, and 2,3,5,6-C6HCl4 and C6Cl5), but the symmetrisation reaction occurs when R = 2,5-C6H3Cl2; 2,3,4-C6H2Cl3 and 2,3,4,5-C6HCl4. The action of phen on HgR2 only gives HgR2 (phen) when R = 2,3,4,5-C6HCl4. Compounds of the type RHgMe do not react with phen. These results indicate that steric citects are as important as the electronegativity of R in the formation of tetracoordinated mercury compounds. 相似文献
7.
The syntheses of two new monothiocarbamate ligands and selected transition element complexes of each are reported. The complexes of indoline-N-carbothioate (intc) prepared are: NiL2·1.5H2O, ZnL2, NiL2·2py, ZnL2·2py. The complexes of indole N-carbothioate (iltc) are: NiL′2, ZnL′2, Cul′. IR spectral results support a bidentate ligand behavior for both new monothiocarbamates except in ZnL2·2py. Comparison of the IR spectral features of bis(indolylcarbamoyl)-disulfide with that of coordinated indole-N-carbothioate allowed an assignment of the C-S and C-O vibrational frequencies. Evidence for differences in major resonance contributions to the electronic structures of each new ligand are presented. The crystal structure of the bis(indolylcarbamoyl)disulphide is also presented and a comparison is made to pyrrole-N-carbothioate, another aromatic amine monothiocarbamate. The disulphide crystallizes in the centrosymmetric monoclinic space group P21/c with a = 15.64(4)Å, b = 5.228(1)Å, c = 19.271(7)Å, β = 97.20(2)°, V = 1564(1)Å3, d(obsd)(calcd) = (1.50)(1.52) for a molecular weight = 356.1 and Z = 4. Diffraction data were collected with a Syntex P diffractiometer with CuKα radiation. Least squares refinement resulted in Rf = 7.0% for all 1213 non zero reflections have (I)> 3σ(I). 相似文献
8.
There appears to be a correlation between the 31P chemical shift differences between A+ and AX (Δ1), and between A+ and AX2? (Δ2), where A+ is a phosphonium ion and X is an anionic ligand. This relationship holds for a wide range of substituents on phosphorus, despite the expected changes in hybridisation along the series, and is very useful for predicting the shifts of new or unknown species. 相似文献
9.
Molar excess volumes and molar excess enthalpies of methylenebromide + aromatic hydrocarbon mixtures
Molar excess volumes Ve and molar excess enthalpies He of binary methylenebromide (i) +benzene. +toluene, and + o?, + m? and + p-xylene (j) mixtures have been determined at 298.15 and 308.15 K. The data have been analysed in terms of recent approaches for solutions of nonelectrolytes, and the results suggest that these mixtures are characterised by specific interactions between the components. Self-volume interaction coefficients ViiVjj have also been evaluated. 相似文献
10.
S. M. Van Der Kerk J. C. Roos-Venekamp A. J. M. Van Beijnen G. J. M. Van Der Kerk 《Polyhedron》1983,2(12):1337-1343
Some potential methylborylene-generating systems were investigated, using cyclohexene as the trapping agent. Methylborylene, generated by the system 2C8K/MeBBr2, reacts with cyclohexene to yield 2-methyl-2-boratricyclo-[7.4.0.03.8]-tridecane (MBTT) Ia. In the course of the work an isomer of MBTT was synthesized along a completely different route and compared with Ia. With the system 2C8K/MeBBr2, only cyclic olefins were converted to analogues of MBTT. An acyclic olefin and a conjugated diene yielded only haloboration products. Possible mechanisms leading to the formation of MBTT Ia are discussed. 相似文献
11.
(C6F5)3Sb has been found to react with interhalogens and halo-pseudohalogens, IX(X = Cl, Br, N3 and NCO), pseudohalogen (SCN), and elemental sulphur to give oxidative addition products (I–VI). (C6F5)3SbS(VI) may also be prepared by the reaction of (C6F5)3SbCl2 with H2S. Metathetical reactions of (C6F5)3SbCl2 with appropriate metallic salts yield covalent pentacoordinate disubstituted products (V, VII–XII) of the general formula, (C6F5)3SbY2 (Y = NCS, NCO, ?ONCMe2, ?ONCMePh O and p-NO2C6H4OCO). Treatment of (C6F5)3SbCl2 with aqueous NaN3 gives the binuclear oxo-bridge compound, [(C6F5)3SbOSb(C6F5)3](N3)2·(III) and (IV) are also accessible by displacement reaction of (I) or (II) with the corresponding metallic salt. Molecular weight, conductance measurements, and IR spectra on the new organoantimony(V) derivatives have been obtained.Reductive cleavage reactions of (C6F5)3SbS with hexaaryldileads, Ar6Pb2(Ar = Phenyl, p-tolyl) produce (C6F5)3Sb and the corresponding bis(triaryllead) sulphide but treatment of (C6F5)3SbX2(X = NCO, Cl) with Ar6Pb2 gave Ar4Pb and Ar2PbX2 together with (C6F5)3Sb.(C6F5)3SbCl2 and bis(triorganotin)sulphides undergo exchange of anionic groups. 相似文献
12.
John D. Donaldson Susan M. Grimes Arthur F. Lec. Holding Michelle Hornby 《Polyhedron》1985,4(7):1293-1295
The thermal decomposition of triphenyltin hydroxide in the temperature range 25–400°C has been studied. The decomposition products formed at each stage have been isolated and characterised. A decomposition scheme involving a reductive-elimination reaction is proposed. The proportions of this reaction and the accompanying reaction are dependent on the mode of heating. 相似文献
13.
Absorption spectra of dysprosium compounds were measured in amides and D2O within the 5500–35000 cm?1 region and in alcohols within the 7000–34300 cm?1 region. The oscillator strengths of f-f absorptions bands below 35000 cm?1 were determined. The intensities of the Dy3+ ground state absorption were analyzed according to the Judd-Ofelt theory of forced electric dipole transitions.A good fit to the measurements was obtained with the intensity parameter given in Tables 4–6. The polarizability effect on the intensity of the f-f transition with high value matrix elements U(4) and U(6) were considered. 相似文献
14.
A series of new μ-peroxodicobalt(III) complexes have been prepared and characterized. Studies of the chemical and physical properties of these complexes were carried out using IR, electronic and NMR spectroscopy along with conductivity, magnetic susceptibility and thermogravimetric measurements. The complexes [Co2(dpk·dien)2 (dpk·H2O)O2] (ClO4)4·H2O, [Co2(dpk)4(py)2O2](ClO4)4·4H2O, [Co2(dpk·H2O4(py)2O2] (ClO4)4, and [Co2(dpk)2(terpy)2O2](ClO4)4 were prepared by bubbling oxygen through a solution containing Co(NO3)2, NaClO4, and the appropriate ligand mixture. Electronic spectral studies are consistent with the formulation as binuclear peroxo complexes. Thermogravimetric studies reveal the stoichiometric loss of O2 and H2O below 100°C. The auxiliary ligands, pyridine (py), diethylenetriamine (dien) and terpyridine (terpy) are lost at higher temperatures. Molar conductance of these complexes is indicative of a 4:1 electrolyte while magnetic susceptibility measurements indicate the diamagnetic character of the above four complexes. Three additional complexes of Co(II) containing di-2-pyridyl ketone (dpk) and terpy were prepared to compare spectral changes upon oxygenation. 相似文献
15.
A sample clamp assembly has been devised for the dynamic mechanical analysis of thin cellulose and paper sheets. The assembly, used with the DuPont 981 DMA, provides an arched sample cross-section to prevent buckling deformation of the sample. The applicability of this technique is demonstrated by measurements on original and thermally-aged newsprints. 相似文献
16.
X-substituted anilines (X = H, 2-Me, 4-Me or 2-Cl) and cyclohexylamine are shown to add to the tropylium ring of cation [(η)-C7H7)W(CO)3]+ to give the corresponding ring adducts of tricarbonyl(cyclohepta-1,3,5-triene)tungsten. Kinetic studies have demonstrated that the anilines form the triene ring adducts via the rapid pre-equilibrium formation of a π-complex, which rearranges in a rate-determining fashion to form a cationic triene intermediate [(1–6-η-C6H7.NH2R)-W(CO)3]+ (R = C6H5, 2-MeC6H4, 4-MeC6H4 or 2-ClC6H4); from this the final product is rapidly formed via amine- or solvent-assisted proton loss. With the aliphatic cyclohexylamine, the cationic triene intermediate is formed directly, followed by competing rate-determining solvent- and amine-assisted proton removal. 相似文献
17.
Cyclopalladation occurs for 2-pyridylhydrazones(HL) of p-methyl-, p-methoxy-, p-chloro-, and p-nitro-acetophenone, and 3-acetyl- and 2-acetyl-thiophene with lithium tetrahalopalladate to give the complexes [PdXL] (X = Cl and Br) and some iodo complexes are prepared by metathesis of the chloro complexes with lithium iodide. These complexes are characterized spectroscopically. The hydrazones are coordinated to palladium through benzene or thiophene ortho-carbon, hydrazone-nitrogen, and pyridine ring-nitrogen atoms forming fused five-membered chelate rings. 相似文献
18.
19.
The solvent combination of N-methylpyrrolidone (NMP) and monoethyleneglycol (MEG) is used in industry for the separation of aromatics and nonaromatics (Arosolvan process).In this paper experimental results obtained for the system n-heptane—toluene—N-methylpyrrolidone/monoethyleneglycol are presented. Liquid—liquid equilibrium compositions were obtained at three different temperatures (50°C, 60°C, 70°C). For each temperature, three different solvent compositions corresponding to weight ratios of NMP/MEG equal to , and were considered. The different sets of experimental results obtained are correlated using the NRTL equations.Equilibrium compositions obtained using an industrial solvent mixture (NMP/MEG-) are compared with data based on the use of purified solvents. 相似文献
20.
The ESCA characterization of three similar new amorphous addition complexes of tin dichloride with tetradentate aromatic Schiff bases has been carried out. The results support the previously proposed ionic structure. 相似文献