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11.
de Oliveira MC Scarpellini M Neves A Terenzi H Bortoluzzi AJ Szpoganics B Greatti A Mangrich AS de Souza EM Fernandez PM Soares MR 《Inorganic chemistry》2005,44(4):921-929
The crystal structures and redox and UV-vis/EPR spectroscopic properties of two new mononuclear copper(II) complexes, [Cu(HL1)Cl2] (1) and [Cu(L1)Cl] (2), prepared through the reaction between copper(II) chloride and the ligand 2-[(bis(pyridylmethyl)amino)methyl]-4-methyl-6-formylphenol (HL1) under distinct base conditions, are reported along with solution studies. Also, we demonstrate that these CuII complexes are able to cleave unactivated peptide bonds from bovine serum albumin (BSA) and the thermostable enzyme Taq DNA polymerase at micromolar concentration, under mild pH and temperature conditions. The cleavage activity seems to be specific with defined proteolytic fragments appearing after protein treatment. The location of the specific cleavage sites was tentatively assigned to solvent-accessible portions of the protein. These are two of the most active Cu(II) complexes described to date, since their cleavage activity is detected in minutes and evidence is here presented for a hydrolytic mechanism mediating protein cleavage by these complexes. 相似文献
12.
Azulene as a ligand in cationic rhodium and iridium complexes. Crystal structure of [Rh(TFB)(az)]PF6
L.A. Oro M. Valderrama P. Cifuentes C. Foces-Foces F.H. Cano 《Journal of organometallic chemistry》1984,276(1):67-77
Rhodium or iridium complexes of formula [M(diolefin)(az)]+ have been prepared by treating [MCl(diolefin)]2 complexes with silver salts and azulene, and also by treating [Rh(diolefin)2]+ with azulene. The reactions of some representative complexes have been studied. Reaction of [M(C5Me5)(Me2CO)3]2+ with azulene appears to give dinuclear diazulene cationic complexes. The crystal structure of compound [Rh(TFB)(az)]PF6 has been solved by X-ray methods. It crystallizes in the space group P21/c with cell constants 8.4241(4), 16.6911(8), 15.0026(7) Å, 95.897(6)°. Refinement gave R = 0.027 and Rw = 0.032 for 2991 observed reflexions. The Rh atom is coordinated to the five-membered ring, with RhC distances shortest for the atoms which are trans to the diolefinic double bonds. The bonding scheme within the azulene ligand differs from that in the parent hydrocarbon. 相似文献
13.
Mauricio Alcolea Palafox Nerea Iza Manuel Gil Jos Luís Núez 《International journal of quantum chemistry》2002,89(1):25-47
A quantum chemical study of several complex monocyclic 4‐benzoyl‐4‐phenyl‐β‐lactam derivatives was carried out using cyclobutane, azetidine, 2‐azetidinone, 1‐methyl‐2‐azetidinone, and 3‐methyl‐2‐azetidinone as model compounds. The optimum geometry was obtained for the different conformations. The planarity of the ring was discussed in terms of the influence of the substituents on the amide resonance. To better analyze the amide resonance and the activity of the β‐lactam ring, a vibrational study was also carried out. To examine the influence of solvent polarity on the carbonyl bands, the Fourier transform–infrared (FT‐IR) spectra of the β‐lactam monocyclic derivatives were recorded in CCl4, C6H6, and CHCl3 solutions. The normal vibrations of the β‐lactam ring in the model compounds were characterized and used in the analysis of the β‐ring of more complex derivatives. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002 相似文献
14.
The modeling of liquid–vapor equilibrium in ternary mixtures that include substances found in alcoholic distillation processes of wine and musts is analyzed. In particular, vapor–liquid equilibrium in ternary mixtures containing water + ethanol + cogener has been modeled using parameters obtained from binary mixture data only. The congeners are substances that although present in very low concentrations, of the order of part per million, 10−6 to 10−4 mg/L, are important enological parameters [1] and [2]. In this work two predictive models, the PSRK equation of state and the UNIFAC liquid phase model and two semipredictive activity coefficient models: NRTL and UNIQUAC have been used. The results given by these different models have been compared with literature data and conclusions about the accuracy of the models studied are drawn, recommending the best models for correlating and predicting the phase equilibrium in this type of mixtures. 相似文献
15.
Kim K Webster S Levi N Carroll DL Pinto MR Schanze KS 《Langmuir : the ACS journal of surfaces and colloids》2005,21(11):5207-5211
We describe the preparation and characterization of a photonic crystal filled with a luminescent conjugated polyelectrolyte, sulfonated poly(phenylene ethynylene). The conjugated polymer was coated onto the nanospheres by the layer-by-layer method and assembled directly into a fluorescent opal structure avoiding the defects associated with post-filling schemes. These structures exhibit strong angle-dependent luminescent properties. By using multiple layers, we further demonstrate control over the emissive bands of the opal. 相似文献
16.
Yolanda Prieto Marcelo Muoz Vernica Arancibia Mauricio Valderrama Fernando J. Lahoz M. Luisa Martín 《Polyhedron》2007,26(18):5527-5532
The reaction of the dimer complex [{Ru(CO)3Cl2}2] with the ligands 4,6-dichloroquinoline-5,8-dione and 6-methoxybenzo[g]quinoline-5,10-dione in ethanol solution led to the neutral mononuclear complexes of general formula [Ru(CO)2Cl2(κ2-quinolinedione-N,O)]. The complexes were characterized by elemental analysis, IR and RMN spectroscopy, and the molecular structure of [Ru(CO)2Cl2(6-methoxybenzo[g]quinoline-5,10-dione)] was determined by single-crystal X-ray diffraction. The redox chemistry of ligands and complexes was investigated by cyclic voltammetry, and their potential antitumor activity was also evaluated. 相似文献
17.
Mauricio Gomes Constantino Kleber Thiago de OliveiraAdilson Beatriz Gil Valdo José da Silva 《Tetrahedron letters》2003,44(13):2641-2643
A synthesis of a functionalized bicyclo[6.2.1]undecane, N-(7-hydroxymethyl-bicyclo[6.2.1]undeca-3,5,9-trien-2-yl)-4-methyl-benzenesulfonamide, is described. Starting with a [6+4] cycloaddition between cyclopentadiene and cycloheptatrienone, the final product was prepared in five steps with an overall 37% yield. The remarkable resistance to hydrolysis of an intermediate lactam was overcome by tosylating the amide and reducing with LiAlH4. 相似文献
18.
Giovanni C. Petrucelli Mauricio A. Meirinho Thais R. Macedo Claudio Airoldi 《Thermochimica Acta》2006,450(1-2):16-21
Synthesized hydrated lamellar acidic crystalline magadiite (H2Si14O29·2H2O) nanocompound was used as host for intercalation of polar n-alkylmonoamine molecules of the general formula H3C(CH2)nNH2 (n = 1–6) in aqueous solution. The original interlayer distance (d) of 1500 pm, determined by X-ray powder diffraction patterns, increases after intercalation. The values correlated with the number of aliphatic amine carbon (nc) atoms: d = [(1312 ± 11) + (21 ± 2)]nc. The amount of intercalated amines (Ns), decreased as nc increased: Ns = [(5.82 ± 0.04) − (0.45 ± 0.01)]nc. The acidic layered nanocompound was calorimetrically titrated with the amines and the thermodynamic data gave exothermic values for all guest molecules, as shown by the correlation: ΔintH = −[(24.45 ± 0.49) − (1.91 ± 0.10)]nc and d = [(1576 ± 16) − (10.8 ± 1.0)]ΔintH. The negative values of the Gibbs energies and the positive entropies also presented the correlations: ΔintG = −[(22.8 ± 0.2) − (0.2 ± 0.1)]nc and ΔintS = [(6 ± 1) + (5 ± 1)]nc, respectively. 相似文献
19.
20.
The PF6 salts of the new cationic hexamethylborazinerhodium(I) complexes of general formula [Rh(Me3B3N3Me3)(LL′)]+ (LL′= 1,5-cyclooctadiene, norbornadiene, tetrafluorobenzobarrelene, trimethyltetrafluorobenzobarrelene, L = L′ = ethylene, CO) have been prepared from the reaction between [RhCl(LL′)]2, Me3B3NMe3, and AgPF6 in dichloromethane. These complexes are very labile, undergoing rapid ring ligand exchange in solution with σ and π-donor ligands. The synthesis of [Rh(η6-naphthalene)(COD)]PF6 is also described. The properties and NMR and IR spectroscopic characteristics of the new compounds are briefly discussed. 相似文献