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1.
Summary -Cp2Cr reacts with PX3 (X = Cl, Br or I) to give monocyclopentadienylchromium(III) derivatives -CpCrX2 (X = Cl, Br or I), while oxidative additions of IBr and ICl to -Cp2Cr give the corresponding mixed halogenated derivatives, -Cp2CrIX (X = Cl or Br). All products have been characterized by elemental analyses, magnetic moment measurements and by i.r. and e.p.r. spectra.  相似文献   

2.
Stacking reactions of the dicationic fragments [LM]2+ (LM = (-C6H6)Ru, (-C6H3Me3)Ru, or (-C5Me5)Rh) with the complex (-C5H5)Co(-C4H4BCy) (Cy = cyclo-C6H11) afforded new dicationic 30-electron triple-decker complexes [(-C5H5)Co(-:-C4H4BCy)ML](BF4)2 containing a cyclohexyl-substituted borole ligand in the central position.  相似文献   

3.
New cationic complexes [(6-C13H10)Fe(5-Cp*)]PF6 and [(6-9-CH3-C13H9)Fe(5-Cp*)]PF6 were obtained by the reaction of Cp*Fe(CO)2Br with fluorene and 9-methylfluorene, respectively. Deprotonation of these complexes byt-BuOK in THF affords zwitter-ionic compounds (6-C13H9)Fe(5-Cp*) and (6-9-CH3-C13H8)Fe(5-Cp*) (A). WhenA is heated in nonane at 150 °C it undergoes 65 inter-ring rearrangement with the formation of hexamethyldibenzoferrocene (B). The electrochemical behavior ofA andB was studied by cyclic voltammetry. One-electron reduction ofA andB to the corresponding radical anions induces inter-ring haptotropic rearrangementA .–B .–. The equilibrium in the 19 state is shifted to the 6-isomeric radical anionA .–, while in the 18 precursors, it shifts to the 5-isomerB.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 319–324, February, 1994.The authors are grateful to D. V. Zagorevskii (A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences) for recording and interpreting the mass spectra, and to A. A. Borisenko (Moscow State University) for recording the NMR spectra.This work was financially supported by the Russian Foundation for Basic Research (Grant 93-03-5209).  相似文献   

4.
Summary Eight complexes of the chelated bis(-cyclopenta-dienyl)titanium(IV) cation. [-Cp2TiL][MX4] (L = acetyl-acetone, M = GaIII, InIII or TiIII: X = Cl, Br or I) have been isolated from aqueous solution and characterised by elemental analyses and i.r. data. Their ionic nature has been confirmed by conductance measurements.  相似文献   

5.
The viscosities of most alkali and tetraalkylammonium halides have been measured in water at 25°C. The relative viscosities can be fitted, up to 1M, with the relation r =1+A c1/2+B c+D 2. TheA term depends on long-range coulombic forces, andB is a function of the size and hydration of the solute. When combined with partial-molal-volume data, the difference B –0.0025V° is mostly a measure of the solute-solvent interactions. IonicB are obtained if the tetraethylammonium ion is assumed to obey Einstein's law. TheD parameter depends on higher terms of the long-range coulombic forces, on higher terms of the hydrodynamic effect, and on structural solute-solute interactions. As such, it cannot be interpreted unambiguously.  相似文献   

6.
The problem of existence of 3—-complexes of C60 fullerene with transition metal atoms is discussed. The complexes C60R3Co(CO)3 (R = H, F, Cl, Br), C60H3NiCp, and C60H3Fe(CO)Cp, where C60R3 is an allyl derivative of C60 fullerene, were shown to be sufficiently stable. In these complexes the metal atoms are 3—-bound to the fullerene cage. In contrast to this, the metal atoms in the C60H3Li and C60H3FeCp complexes are 5—-coordinated to the carbon cage. Density functional calculations were carried out with the Perdew—Burke—Ernzerhof exchange-correlation potential (PBE). It was concluded that the type of bonding in the complexes of allyl derivatives of C60 fullerene depends on the nature of the species attached. Among the systems studied, the maximum energy of the 3—-bond was obtained for the C60H3NiCp complex. The results obtained can be useful in the design of synthesis of new fullerene derivatives with the 3—-coordination of the transition metal atoms to the carbon cage.  相似文献   

7.
Summary -(5:5-Fulvalene)-di--hydrido-bis(5-cyclopentadienyltitanium) (1) can be prepared by the reduction of Cp2TiCl2 with LiAlH4 in methylbenzenes and in tetralin at their boiling temperatures in yields greater than 90%. The reduction proceedsvia the bis(5-cyclopentadienyl)titanium(III) chloride dimer which is further transformed into the unstable [Cp2TiH] species. Thermal decomposition of the latter accompanied by hydrogen evolution gives rise to (1). -(5:5-Fulvalene)--hydrido--chloro-bis(5-cyclopentadienyltitanium), the first fulvalene containing compound observed in the system is formed by hydrido-chloro exchange of (1) with (Cp2TiCl)2 and aluminium chlorohydrides.  相似文献   

8.
Summary The -allylmolybdenum(II) complexes [MoX(CO)2-(NCMe)2(3-C3H4R)] (X=Cl, Br and I; R=H and 2-Me) react either in dichloromethane or acetonitrile with thiosemicarbazones to give the new complexes [MoX-(CO)2(RRCNNHCSNH2)(3-C3H4R)] (R=H or Me; R'=Me, Et, Pr or Ph)via displacement of acetonitrile ligands.  相似文献   

9.
It was found that the 16-C6H5Cr(CO)3 ligand migrates into the cyclopentadienyl ring when the 5-C5H5(CO)2Fe 16-C6H5Cr(CO)3 binuclear complex is metallated with BunLi. Under the same conditions, no migration of the phenyl ligand in the 5-C5H5(CO)2Fe 1-C6H5 complex was observed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 325–326, February, 1994.  相似文献   

10.
The diffusion deposition of submicron aerosol particles of a finite size on a model filter composed of parallel ultrafine fibers with a radius comparable with the mean free path of air molecules was considered. The diffusion capture coefficient with allowance made for particle interception DR is found by the numerical solution of the elliptic equation of steady-state convective diffusion in the wide ranges of interception parameter R, Peclet (Pe) and Knudsen (Kn) numbers at small Reynolds numbers. It was shown that, at small Kn numbers, the DR value exceeds the sum of capture coefficients due to specific deposition mechanisms, interception and diffusion, = R + D , whereas, at Kn > 1, DR . Within the range of intermediate Pe, Kn, and R numbers, the radius of the most penetrating particles is higher than the fiber radius.  相似文献   

11.
Binuclear and trinuclear transition-metal -allenyl complexes—especially mixedmetal complexes—are reviewed. In recent years, a number of such compounds have been prepared by use of several synthetic methods. The most general of these methods, viz. reactions of metal propargyls and of the lower nuclearity metal allenyls with low-valent metal complexes such as metal carbonyls and platinum(0) compounds, are considered in some detail. The structures of the binuclear metal -1,2- and -3,2-allenyl complexes and of the trinuclear metal 3-1,2,2-allenyl complexes—both triangular and open—are presented and compared. Trends in the1H and13C NMR spectroscopic properties of these compounds are examined. Some aspects of reaction chemistry of the heteronuclear platinum-ruthenium -1,2-allenyl complexes are presented.  相似文献   

12.
Xu  Feng  Sun  Wen-Hua  Yang  Shi-Yan  Yin  Yan-Qi  Wu  Qin-Jin  Yu  Kai-Bei 《Transition Metal Chemistry》1997,22(2):176-179
HFe2Co(CO)9(3-S) reacts with (5-Cp)Mo(CO)3Cl in refluxing THF to give heterometallic trinuclear clusters (5-Cp)MoFeCo(CO)8(3-S) and [(5-Cp)Mo]2Fe(CO)7-(3-S), which have been characterized by elemental analyses, i.r., 1H- and 13C-n.m.r. and X-ray crystal structure determination. An electrophilic addition–elimination sequence is proposed for their formation.  相似文献   

13.
The calculated parameters of the steric and electronic structure and shielding constants of 2- (3-penten-2-one)Fe(CO)4, 2-(3-penten-2-one)M(CO)5, 4-(3-penten-2-one)Fe(CO)3, and 4-(3-penten-2-one) ·M (CO)4 (M = Cr, Mo, W) nicely agree with the experiment. Coordination of the -enone with transition metals significantly distorts the conjugation between the C = C and C = O bonds.  相似文献   

14.
Summary The [2.2]paracyclophane cluster, Ru6C(CO)14( 3- 2 2 2-C16H16) (1), undergoes reaction with Me3NO and triphenylphosphine to yield Ru6C(CO)13( 3- 2 2 2-C16H16)(PPh3) (2), which may also be produced from (1) by thermolysis with PPh3 in THF. Compound (2) has been fully characterized in solution by spectroscopy and in the solid state by a single crystal X-ray diffraction analysis at 277 K, and its structure is compared with that of the parent cluster, (1). Using the same synthetic procedures, the tricyclohexylphosphine analogue, Ru6C(CO)13( 3- 2 2 2-C16H16)(PCy3) (3), has also been prepared and characterized spectroscopically. A comparison of the chemical shifts of the 577-01 protons in the 1H-n.m.r. spectra of compounds (1)–(3) together with a variety of other [2.2]paracyclophane and benzene clusters has been made.  相似文献   

15.
Binuclear RhIII and RuII complexes of the [M1-CN-M2]+BF 4 (M1 and/or M2 are (5-Cp)(3-C3H5)Rh and (6-C6H6)(3-C3H5)Ru) type, heteronuclear organometallic compound (5-Cp)(3-C3H5)RhCNPd(3-C3H5)Cl, and mononuclear RhIII and RuII complexes [(3-C3H5)LM(MeCN)]+ BF4 (M = Rh, L = 5-Cp; M = Ru, L = 6-C6H6) were synthesized. An electrochemical study of these compounds in solutions demonstrates that the bond between the bridged CN ligand and the metal atoms is rather strong, and there is no dissociation into mononuclear fragments in solutions. The kinetics of the reaction of [(5-Cp)(3-C3H5)Rh(MeCN)]+ BF4 with halide ions was studied by electrochemical methods. The ligand exchange proceeds by a bimolecular dissociative-exchange mechanism.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 968–973, May, 1995.  相似文献   

16.
Synthetic procedures for preparing 2- and 4-complexes of chalcone and benzalacetone with hexacarbonyl mononuclear complexes of Group VIB metals were developed and conditions for selective 2- and 4-coordination of the heterodiene ligand were established. Hydrophosphorylation of the obtained complexes proceeds in the coordination sphere of the metal by the Abramov reaction scheme and yields the corresponding 2-coordinated -hydroxyphosphonates. As follows from quantum-chemical calculations, -coordination with metals makes the heterodienes no longer planar, which explains their regioselective phosphorylation by the more electrophilic carbonyl group.  相似文献   

17.
The effect of solely intermolecular interactions due to hydrophobic alkyl substituents on the flow behaviour of hmHEC solutions was determined via comparison of the structure–property relationships of hmHECs and HECs based on the overlap parameter c[]. For this purpose the 0–[]–c relationship for HEC was determined to be 0=8.91·10–4+8.91·10–4·c[]+1.07·10–3(c[])2+1.83·10–7(c[])5.56. In addition the structure–property relationship for the longest relaxation time via the –[]–c relationship ·c1+1/a=2.65·10–8(c[])2+4.25·10–8(c[])3+5.44·10–12(c[])5.27 has been determined. Although the hmHECs had a higher zero shear viscosity than HECs of comparable overlap parameters at a range of 1<c[]<13, the flow curves could be described via the same –[]–c relationship in that range, indicating a timescale of the intermolecular interactions below the longest relaxation time.The behaviour of the supramolecular structures in solution with an applied shear field was characterized by rheo-optical analysis of the shear thickening behaviour which occurs with addition of surfactant. Contrary to expectations, a slope >1 of the flow birefringence n as a function of shear rate could be observed in double logarithmic plotting. The degree of orientation of the flow birefringence primarily decreases with increasing shear rate, but increases later on at a characteristic shear rate. These two exceptional phenomena can be explained by a pronounced anisotropy of the polymer coils caused by the dilatant flow.This assumption is backed up by the occurrence of a maximum in the dichroism curves which is caused by a finite stability of the aggregated structures in solution. On a molecular basis, these observations agree with the theoretically predicted (Witten and Cohen) transition from intra- to intermolecular polymer micelles. The detected aggregates correspond with the polymer chains that are aligned in one micelle.Abbreviations a Exponent of the Mark–Houwink relationship - c[]* Critical concentration (determined by intrinsic viscosity) - cLS* Critical concentration (determined by light scattering) - HASE Hydrophobically modified alkali-swellable emulsions - HEUR Hydrophobically modified ethoxylated urethanes - hmHEC Hydrophobically modified hydroxyethylcellulose - HEC Hydroxyethylcellulose - HPMC Hydroxypropylmethylcellulose - M Molecular mass - MS Molar degree of substitution - n Slope of the flow curve - SEC Size exclusion chromatography - RG Radius of gyration - Viscosity - 0 Zero-shear viscosity - sp Specific viscosity - Longest relaxation time - n Birefringence - ni Intrinsic birefringence - nf Form birefringence - n Dichroism - Orientation of the birefringence - ̇ Shear rate  相似文献   

18.
Summary The reduction of Cp2TiCl2 with LiAlH4 in olefinic solvents at temperatures above 100° leads to the formation of µ-( 5 : 5-fulvalene)-di-µ-chloro-bis( 5-cyclopentadienyl-titanium) (1) and finally to µ-( 5 : 15-fulvalene)-di-µ-hydrido-bis ( 5-cyclopentadienyltitanium). The first step of the reduction includes mainly the formation of the dimer of bis( 5-cyclopentadienyl)titanium(III) chloride, (Cp2TiCl)2. The mechanism of its conversion into (1) involves the formation of an intermediate bis( 5-cyclopentadienyl)titanium(III) hydride species which reacts immediately with the olefinic solvent to give bis( 5-cyclopentadienyl)alkyltitanium(III) compounds. The formation of the fulvalene ligand in (1) is explained by the interaction of the alkyltitanium compound with the cyclopentadienyl ligands of (Cp2TiCl)2 resulting in hydrogen transfer to the olefinic solvent.  相似文献   

19.
Reaction of Ru4(CO)13(3-PPh) (1) with the 1,3,5-hexatriyne Me3SiCCCCC CSiMe3 under mild thermal conditions affords initially Ru4(CO)10(-CO)2{4-1,1,2-P(Ph)C(CCSiMe3)C(CCSiMe3) (2), via the facile formation of a P–C bond in a manner similar to that demonstrated previously with alkynes and diynes. The 62-CVE cluster 2 readily decarbonylates to give crystallographically characterised Ru4(CO)10(-CO)(4-PPh){4-1,1,2,2-Me3SiCCC2CCSiMe3} (3). Attempts to further incorporate the pendant alkyne moieties in 3 into the Ru4 coordination environment were partially successful with Ru4(CO)10(4-PPh)(4-1,1,3,3-RC4R') (4, R/R'=SiMe3/CCSiMe3) being formed as a minor product together with the unusual toluene coordinated species Ru4(CO)7(6-C6H5Me)(4-PPh)(4-1,1,3,3-Me3SiC4CCSiMe4) (5). Cluster 3 reacts with an excess of Me3SiCCCCCCSiMe3 to give the open chain cluster Ru4(CO)9(3-PPh){4-2,2,4,4,-C4(CCSiMe3)(SiMe3)C4(CCSiMe3)3} (6).  相似文献   

20.
Summary We report values of the correlated dynamic dipole polarizability for the halides HX and CH3X (X = F, Cl and Br). The polarizabilities are calculated within the second-order polarization propagator approximation (SOPPA). The correlated results are in much better agreement with the available experimental results, compared to RPA. We also report the second-order dipole moments using both the relaxed and unrelaxed MP2 density matrices. The relaxed results are in better agreement with experiment.  相似文献   

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