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1.
The reactivity of [Pt(SbPh3)3], a compound of zerovalent platinum, exceptionally stable in air, is described. The compounds [{Pt(SbPh3)3}2N2], containing bridging dinitrogen, [{Pt(SbPh3)3}2C2], with an ethynediyl group also bridging, and [Pt(CO)2(SbPh3)2], were all obtained under ordinary pressure of nitrogen, acetylene or carbon monoxide, respectively, and are also described. Among the products of the reactions, the dimer [PtBr3(SbPh3)2]2 and the mixed complexes [PtL2(SbPh3)2] (L = PPh3, AsPh3) were also obtained. Some of these complexes are luminescent when excited by u.v. radiation.  相似文献   

2.
S. Ramgopal 《Tetrahedron letters》2007,48(23):4043-4045
Hunsdiecker reactions with α,β-unsaturated carboxylic acids were conducted under solvent-free conditions in the presence of a few drops of HNO3 together with a variety of metal nitrates [Mg(NO3)2, Sr(NO3)2], Al(NO3)3, Ca(NO3)2, Ni(NO3)2, Cd(NO3)2, Zn(NO3)2, Hg(NO3)2, AgNO3, ZrO(NO3)2, UO2(NO3)2, Th(NO3)2] or ammonium nitrate. α,β-Unsaturated aromatic carboxylic acids underwent nitro decarboxylation to afford β-nitro styrenes in moderate to good yields, while α,β-unsaturated aliphatic carboxylic acids underwent decarboxylation to yield the corresponding nitro derivatives.  相似文献   

3.
The reaction between cis-[Pt(NH3)2Cl2], N1-(2"-tetrahydrofuranyl)-5-fluorouracil (HL), and NaOH (taken in a molar ratio of 1 : 1 : 1) or between cis-[Pt(NH3)2Cl2], HL, and Ag2O (taken in the molar ratio of 1 : 1 : 0.5) was used to synthesize complexes Ia (in the case of NaOH) or Ib (in the case of Ag2O) with composition Pt(NH3)2LCl. The model complex [Pt(NH3)3L]NO3 (II) was synthesized by the reaction between [Pt(NH3)3Cl]Cl, HL, AgNO3, and Ag2O (1 : 1 : 1 : 0.5). The obtained compounds were characterized by chemical analysis, chromatography, thermogravimetry, conductometry, potentiometry, IR, electronic, and NMR spectroscopies. Complexes Ia and Ib were found to have both similar and different properties. The structures of the compounds and the type of L coordination to platinum(II) were suggested. Cytotoxic properties of Iaand Ib were studied.  相似文献   

4.
The kinetics of redox -initiated polymerization of acrylic acid (AA) by the systerm Mn3+-isobutyric acid (IBA) in sulfuric acid was studied in the temperature range of 35–50°C. The overall rates of polymerization (Rp), disappearance of manganic ion (?Rm), and degree of polymerization (X n), were measured with variation in [monomer], [Mn3+], [IBA], H+, μ, [Mn2+], and temperature. The polymerization is initiated by the organic free radical that develops from the Mn3+-isobutyric acid oxidation reaction. Two types of termination reactions, one by the metal ion (Mn3+) and the other by the MN3+-isobutyric acid complex are proposed to explain the kinetic results. The various rate parameters were evaluated an discussed.  相似文献   

5.
Systematic studies of several palladium complexes (Pd(OAc)2, [PdCl2(cod)], [Pd2(dba)3], [Pd(PPh3)4], [PdCl(SnCl3)(P{p-Tol}3)2], [Pd2Cl2(SnCl3)2(P{p-Tol}3)2]) as potential catalytic systems for arylation of vinylsiloxanes via Heck coupling reactions are described. Catalytic activity and selectivity were studied for a model reaction of trimethylvinylsilane with PhBr and m-ClC6H6Br and then the most effective systems were applied for functionalisation of tetramethyltetravinylcyclotetrasiloxane and poly(dimethylsiloxane-co-methylvinylsiloxane), leading to the silicone fluids having high refractive index (1.5–1.6).  相似文献   

6.
Sodium thiosulfate has been utilized as a rescuing agent for relief of the toxic effects of cisplatin and carboplatin. In this work, we characterized the kinetics of reactions of the trans-dichloro-platinum(IV) complexes cis-[Pt(NH3)2Cl4], ormaplatin [Pt(dach)Cl4] and trans-[PtCl2(CN)4]2? (anticancer prodrugs and a model compound) with thiosulfate at biologically important pH. An overall second-order rate law was established for the reduction of trans-[PtCl2(CN)4]2? by thiosulfate, and varying the pH from 4.45 to 7.90 had virtually no influence on the reaction rate. In the reactions of thiosulfate with cis-[Pt(NH3)2Cl4] and with [Pt(dach)Cl4], the kinetic traces displayed a fast reduction step followed by a slow substitution involving the intermediate Pt(II) complexes. The reduction step also followed second-order kinetics. Reductions of cis-[Pt(NH3)2Cl4] and [Pt(dach)Cl4] by thiosulfate proceeded with similar rates, presumably due to their similar configurations, whereas the reduction of trans-[PtCl2(CN)4]2? was about 1,000 times faster. A common reduction mechanism is suggested, and the transition state for the rate-determining step has been delineated. The activation parameters are consistent with transfer of Cl+ from the platinum(IV) center to the attacking thiosulfate in the rate-determining step.  相似文献   

7.
The silver(I) nitrate complexes with 2,3-, 2,4-, 2,6-, and 3,5-lutidine (Lut, dimethylpyridine C7H9N), [AgNO3(Lut)2], are synthesized and studied by multinuclear NMR (1H, 13C, and 15N) in various solvents (chloroform, dimethyl sulfoxide, and acetonitrile). The influence of steric and electronic factors of the organic ligand on the parameters of the NMR spectra is revealed. It is shown that the 15N NMR spectra are the most informative. The structure of complex [AgNO3(3,5-Lut)2] is determined. The crystals are monoclinic, space group C2/c, a = 14.599(1) Å, b = 8.422(1) Å, c = 12.954(1) Å, β = 99.60(1)°, V = 1570(2) Å3, ρcalcd = 1.625 g/cm3, Z = 4. The structure is built of discrete neutral complexes [AgNO3(3,5-Lut)2]. The coordination mode of the Ag+ ion includes two nitrogen atoms of two crystallographically equivalent lutidine ligands (Ag-N 2.194(5) Å, angle NAgN 147.6(3)°). The nitrate ion behaves as a weak chelating ligand with respect to the Ag+ ion (Ag…O 2.674(6) Å).  相似文献   

8.
Three ruthenium(II) complexes, [Ru(CO)Cl(PPh3)L], [Ru(CO)Cl(AsPh3)L] and [Ru(CO)Cl(Py)L], were synthesized from the reactions of 2-(benzothiazol-2-yliminomethyl)-phenol (HL) with [RuHCl(CO)B(EPh3)2], where B = PPh3, AsPh3 or pyridine, and E = P or As. All the complexes have been characterized by physicochemical and spectroscopic methods. The structure of the free ligand HL was determined by single crystal X-ray diffraction. The binding of the free ligand and its complexes with CT-DNA was studied using electronic absorption spectroscopy. In addition, the free ligand and its complexes were subjected to antioxidant activity tests, which showed that they all possess significant scavenging effects against DPPH and OH radicals. The in vitro cytotoxicities of the compounds were assessed using tumor (HeLa and MCF-7) cell lines.  相似文献   

9.
The kinetics of precipitation reactions with110AgNO3 of some di (β-chlorethyl) amine derivates and hydrochlorides with esters of N-(p-aminobenzoyl)-L-aspartic acid as carriers in dimethylformamide-water mixture, were studied. The rate constants of these reactions were of the order of 10?4 1 · mol?1 · min?1. The concentrations of the corresponding hydrochloride solutions were measured by radiometric titration with110AgNO3 solution of given concentration.  相似文献   

10.
Summary Nine complexes of FeIIRuII with bis(tertiary phosphines), namely, 1,2-bis(diphenylphosphino)ethane (dppe), 1,2-bis (diphenylphosphino)ethylene (dppen) and o-phenylenebis (diphenylphosphine) (o-diphos) were studied using cyclic voltammetry. The half-wave potentials for the complexes studied are: (1) [FeCl2(dppe)], 0.050V; (2) [Fe(NCS)2(dppe)2], 0.265V; (3) [RuCl2(dppe)2], 0.548V; (4) [FeCl2(dppen)2], 0.225V; (5) [Fe(NCS)2-(dppen)2], 0.290V; (6) [RuCl2(dppen)2], 0.690V; (7) [FeCl2(o-diphos)2] 0.160V; (8) [Fe(NCS)2(o-diphos)2] 0.582V; and (9) [RuCl2(o-diphos)2], 0.265V. The redox potentials are related to the nature of the ligand, the nature of the metal, the stereochemistry of the complex and the ligand field strength.  相似文献   

11.
The structure of one isomer of [Rh3Fe{P(C6H5)2}3(CO)8], synthesised by treatment of [ {Rh(CO)2Cl} 2] with [Fe(CO)4 {P(C6H5)2H} ] in the presence of a base, has been determined by single crystal X-ray diffration. This species rearranges in solution to a second isomer whose structure has been elucidated by 31P NMR spectral measurements. The reactions of these compounds with carbon monoxide are described.  相似文献   

12.
Using a new mathematical treatment, the nature and stability constants of the simple and mixed complex-species of copper(II) with hydroxyde and ammonia as ligands have been determined. The solubility curves of CuO in heterogeneous equilibrium have been identified in function of pH only and in function of pH and pNH3tot at 25° and unit ionic strength (NaClO4). The predominent species in the relatively dilute system limited by the ionic strength are [Cu2+], [Cu(OH)2], [Cu(OH)], [Cu(OH)], [Cu(NH3)], [Cu(NH3)], [Cu(NH3)], [Cu(NH3) (OH)+], [Cu(NH3)3(OH)+] and [Cu(NH3)2(OH)2].  相似文献   

13.
Abstract

We show that the superoxide ion (O2 ??) generated electrochemically from oxygen dissolved in room-temperature ionic liquids (RTILs) reacts with primary and secondary alcohols to form the corresponding ketones and carboxylic acids, respectively. Specifically, we study the conversion of benzhydrol to benzophenone and benzyl alcohol to benzaldehyde/benzoic acid. The kinetics (e.g., rate, selectivity, and yield) for these reactions are also determined as functions of the variations in the structure of the ionic liquids. The RTILs used here are imidazolium-based cations where the functional groups on the imidazolium ring are modified. Specifically, 1-butyl-3-methylimidazolium hexafluorophosphate [bmim][PF6], 1-butyl-2,3-dimethylimidazolium hexafluorophosphate [bdmim][PF6], and 1-hexyl-3-methylimidazolium hexafluorophosphate [hmim][PF6] are used as the reaction medium. These results are compared to an ammonium-based RTIL (N-butyl-N-trimethylammonium bis(trifluoromethylsulfonyl)imide). The results show that the nucleophilic attack by the O2 ?? of both the RTIL and the alcohol, especially that of the H atom at the R2 position of the [bmim][PF6] and [hmim][PF6], greatly affects the yields. No RTIL degradation products were detected for the reactions in [bdmim][PF6] and N-butyl-N-trimethylammonium bis(trifluoromethylsulfonyl)imide ionic liquids. For the benzyl alcohol oxidation reaction in the RTIL, N-butyl-N-trimethylammonium bis(trifluoromethylsulfonyl)imide, benzaldehyde formed did not undergo further oxidation to form benzoic acid, which may be due to the greater hydrophobicity of this RTIL. The competitive reaction kinetics between the alcohol and RTIL component must be considered in the selection of the RTIL solvent system.  相似文献   

14.
The complexes [IrH(CO)(PPh3)3], trans-[IrCI(CO)- (PPh3)2], [RhH(PPh3)4], [Pd(PPh3)4], [Pt(trans-stilbene)(PPh3)2] and [Pt(η3-CH2-COCH2)-(PPh3)2] catalyse the rearrangement of Me3SiCH2C(O)CH2Cl to CH2?C(OSiMe3)-CH2Cl.  相似文献   

15.
The mechanism of Stille reactions (cross‐coupling of ArX with Ar′SnnBu3) performed in the presence of fluoride ions is established. A triple role for fluoride ions is identified from kinetic data on the rate of the reactions of trans‐[ArPdBr(PPh3)2] (Ar=Ph, p‐(CN)C6H4) with Ar′SnBu3 (Ar′=2‐thiophenyl) in the presence of fluoride ions. Fluoride ions promote the rate‐determining transmetallation by formation of trans‐[ArPdF(PPh3)2], which reacts with Ar′SnBu3 (Ar′=Ph, 2‐thiophenyl) at room temperature, in contrast to trans‐[ArPdBr(PPh3)2], which is unreactive. However, the concentration ratio [F?]/[Ar′SnBu3] must not be too high, because of the formation of unreactive anionic stannate [Ar′Sn(F)Bu3]?. This rationalises the two kinetically antagonistic roles exerted by the fluoride ions that are observed experimentally, and is found to be in agreement with the kinetic law. In addition, fluoride ions promote reductive elimination from trans‐[ArPdAr′(PPh3)2] generated in the transmetallation step.  相似文献   

16.
The first dichromium complex with axially bonded anions, [NEt4]2[Cr2(O2CCH3)4(NCS)2], was obtained by reactions of [NEt4]NCS with [Cr2(O2CCH3)4(OH2)2] in ethanol.  相似文献   

17.
Silver crystal nucleation is studied in AgNO3 melts containing Pb(NO3)2 and HNO3 at 250°C by the galvanostatic method. The maximum nucleation overpotential is higher as compared with pure AgNO3 and the exchange current of silver deposition-dissolution is lower. It is found that the added substances and the products of their reactions with the melt are strong oxidants, take part in the electrochemical processes, and induce passivation of the cathodic substrate and the surface of growing silver crystals. Substantial changes in the morphology of the cathodic deposit and certain changes in the silver lattice parameter were observed depending on the oxidant content.  相似文献   

18.
Complexes of syn-thiophene-2-aldoxime (TDH) have been synthesised and characterized on the basis of elemental analysis, molecular weight, conductance, magnetic susceptibility and i. r. spectra. These are [Co(TDH)4Cl2], [Co(TD)2], [Ni(TDH)4Cl2], [Ni(TD)2(TDH)], [Cu(CH3COO)2(TDH)]2, [Cu(TD)(OH)]2 and AgNO3 · 2TDH. In these complexes the ligand (TDH) functions as monodentate (coordinating through nitrogen atom) or bidentate (coordinating through the nitrogen and sulphur atoms). The C? S stretching frequency (of the thiophene ring) at 718 cm?1 may be taken as the criteria for the denticity of this ligand. A shift to lower frequency is observed in the complex if the ligand acts as a bidentate. However, this band is not affected if the ligand acts as monodentate.  相似文献   

19.
Silica‐supported AgNO3 (AgNO3–SiO2) catalyzes the dearomatizing spirocyclization of alkyne‐tethered aromatics far more effectively than the analogous unsupported reagent; in many cases, reactions which fail using unsupported AgNO3 proceed effectively with AgNO3–SiO2. Mechanistic studies indicate that this is a consequence of silver nanoparticle formation on the silica surface combined with a synergistic effect caused by the silica support itself. The remarkable ease with which the reagent can be prepared and used is likely to be of much synthetic importance, in particular, by making nanoparticle catalysis more accessible to non‐specialists.  相似文献   

20.
The kinetics of polymerization of acrylamide (AM) initiated by manganese(III) acetate–ethoxyacetic acid (EAA) redox system in aqueous sulphuric acid was investigated in the temperature range 35–45°C. The effects of variations in [monomer], [Mn3+], [EAA], [H+], and ionic strength on the rates of monomer disappearance (Rp) and Mn3+ disappearance (?Rm) were studied. The polymerization process is initiated by the free radical arising from the oxidation of ethoxyacetic acid by Mn3+ and terminated by the mutual combination of growing polymer radicals. Based on the kinetic results, a suitable reaction scheme is proposed and the rate expressions are derived. The study on degree of polymerization supports the proposed scheme for polymerization. The various rate and thermodynamic parameters are evaluated.  相似文献   

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