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201.
The new ferrole Fe2(CO)6[μ-η2,η4-(Fc)CC{C(H)C(R)S}CC(SiMe3)] [R = SiMe3 (1) and R = Fc (2)] and ruthenoles Ru2(CO)6[μ-η2,η4-(Me3Si)CC{SC(Fc)C(H)}CC(Fc)] 3 and Ru2(CO)6[μ-η2,η4-(Me3Si)CC(SCCFc)C(H)C(Fc)] 4, have been obtained from the reactions of M3(CO)12 (M = Fe, Ru) and FcCCSCCSiMe3 through S-C bond activations and C-C coupling reactions. Thermolysis of Ru2(CO)6[μ3-η2,η4,η3-(Me3Si)CC{SC(Fc)C(SCCSiMe3}Ru(CO)3}CC(Fc)] alone and in the presence of HCCFc, yielded the compounds Ru2(CO)6[μ-η2,η4-(Me3Si)CC{SC(Fc)C(SCCSiMe3)}CC(Fc)] 5 and Ru2(CO)6[μ-η2,η4-(Me3Si)CC{SC(Fc)C(SCCSiMe3)C(H)C(Fc)}CC(Fc)] 6, respectively. The crystal structures of the compounds 1, 3, 4 and 6 are reported. 相似文献
202.
Dr. Marisa Rico‐Santacruz Dr. Elena Serrano Dr. Giuseppe Marcì Dr. Elisa I. García‐López Dr. Javier García‐Martínez 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(50):18338-18344
Mesoporous titania–organosilica nanoparticles comprised of anatase nanocrystals crosslinked with organosilica moieties have been prepared by direct co‐condensation of a titania precursor, tetrabuthylortotitanate (TBOT), with two organosilica precursors, 1,4‐bis(triethoxysilyl) benzene (BTEB) and 1,2‐bis(triethoxysilyl) ethane (BTEE), in mild conditions and in the absence of surfactant. These hybrid materials show both high surface areas (200–360 m2 g?1) and pore volumes (0.3 cm3 g?1) even after calcination, and excellent photoactivity in the degradation of rhodamine 6G and in the partial oxidation of propene under UV irradiation, especially after the calcination of the samples. During calcination, there is a change in the TiIV coordination and an increase in the content of Si?O?Ti moieties in comparison with the uncalcined materials, which seems to be responsible for the enhanced photocatalytic activity of hybrid titania–silica materials as compared to both uncalcined samples and the control TiO2. 相似文献
203.
Highly Stereoselective [4+2] and [3+2] Spiroannulations of 2‐(2‐Oxoindolin‐3‐ylidene)acetic Esters Catalyzed by Bifunctional Thioureas 下载免费PDF全文
Prof. Magda Monari Dr. Elisa Montroni Andrea Nitti Prof. Marco Lombardo Prof. Claudio Trombini Dr. Arianna Quintavalla 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(31):11038-11049
A new Michael–Michael cascade reaction between 2‐(2‐oxoindolin‐3‐ylidene)acetic esters 1 and nitroenoates 2 , catalyzed by bifunctional thioureas, is investigated. The combination of the two Michael reactions results in a novel and facile [4+2] or [3+2] spiroannulation process, which is characterized by the following features: 1) two carbon–carbon bonds and four stereocenters, including a quaternary spiro carbon, are formed under mild conditions; 2) an unprecedented and stereochemically defined substitution pattern on the spirocarbocyclic unit is obtained; 3) the double‐bond configuration of the donor–acceptor nitroenoate 2 determines the absolute configuration of the spiro center, whereas the remaining stereocenters are formed under control of the catalyst. The effect on the final stereochemical outcome of structural variations of each starting material, catalyst, and experimental conditions is analyzed in detail. In particular, the use of specifically designed chiral nitroenoates enables diverse polyfunctional spirocyclohexane derivatives containing six consecutive stereogenic centers to be constructed. To our knowledge, this is the first asymmetric organocatalytic strategy enabling both five‐ and six‐membered β‐nitro spirocarbocyclic oxindoles. 相似文献
204.
Analytical approach for monitoring endocrine-disrupting compounds in urban waste water treatment plants 总被引:1,自引:0,他引:1
Roda A Mirasoli M Michelini E Magliulo M Simoni P Guardigli M Curini R Sergi M Marino A 《Analytical and bioanalytical chemistry》2006,385(4):742-752
The presence of endocrine-disrupting compounds in influent and effluent water samples from four waste water treatment plants located in Italy was studied. The estrogen-like activity of the water samples was measured using a chemiluminescent recombinant yeast assay which is based on genetically engineered yeast cells that express the human estrogen receptor. This receptor, once activated, elicits the expression of the reporter gene lac-Z and, consequently, the production of β-galactosidase, which is then measured by chemiluminescence. To control and minimize sample matrix effects, an external control based on a modified yeast strain stably expressing β-galactosidase was developed and also used in the assay. Rapid and sensitive chemiluminescent enzyme immunoassays were also developed and validated for the quantification of 17β-estradiol, estrone, and estriol in waste water samples. Results from both methods were compared with a reference high-performance liquid chromatography and electrospray ionization tandem mass spectrometry (HPLC ESI-MS-MS) method developed for the quantification of natural estrogens. The recombinant yeast assay revealed a significant estrogenic activity in the influent samples, ranging from 80 to 400 pmol/L 17β-estradiol equivalents (EEQ), which was reduced by 70–95 % in the effluent samples. The yeast assay also showed a systematic 20–30 % overestimation of estrogenic activity relative to the HPLC ESI-MS-MS method, suggesting the presence of other compounds in the samples with estrogenic activity. The chemiluminescent enzyme immunoassays showed the presence of estrogens in the influent samples (mean concentrations: 350–450 pmol/L for estrone, 5–100 pmol/L for 17β-estradiol, 25–300 pmol/L for estriol), with significantly lower concentrations detected in the respective effluent samples. The waste water treatment was able to reduce natural estrogen concentrations by 40–95 %, although a high variability was observed. The enzyme immunoassay data correlated well with data obtained by the HPLC ESI-MS-MS method. Although the recombinant yeast assay represents a useful tool for a first-level screening of estrogenic activity due to its simplicity and high analytical throughput, sample matrix effects observed in waste water of industrial origin were found to strongly affect the yeast cells response, even when properly corrected for using the external control, thereby limiting its use to urban waste water. Its integration with chemiluminescent enzyme immunoassays would improve its performance by reducing false negative results, thereby enabling its use in extensive studies monitoring for the presence of endocrine-disrupting compounds in urban treatment plant effluents. 相似文献
205.
Elena Belluso Donata Bellis Elisa Fornero Silvana Capella Giovanni Ferraris Sergio Coverlizza 《Mikrochimica acta》2006,154(1-2):95-100
A method based on cloud point extraction (CPE) separation/preconcentration of trace cadmium as a prior step to its determination
by graphite furnace atomic absorption spectrometry (GFAAS) has been developed. If the system temperature is higher than the
cloud point temperature (CPT) of the nonionic surfactant of p-octyl polyethyleneglycolphenyether (Triton X-100), the complex
of Cd2+ with 1-(2-pyridylazo)-2-naphthol (PAN) could be extracted into surfactant-rich phase. The chemical variables affecting CPE
were evaluated and optimized. Under the optimum conditions, preconcentrating 10.0 mL of water samples permitted a limit of
detection of 5.9 ng · L−1 (3σ) for cadmium with an enhancement factor of 50 and a relative standard deviation of 2.1% (n = 11, c = 2.0 ng · mL−1). The method was applied to the determination of cadmium in reference material and water samples with satisfactory results. 相似文献
206.
Cavitand‐Grafted Silicon Microcantilevers as a Universal Probe for Illicit and Designer Drugs in Water 下载免费PDF全文
Dr. Elisa Biavardi Dr. Stefania Federici Dr. Cristina Tudisco Dr. Daniela Menozzi Dr. Chiara Massera Andrea Sottini Prof. Guglielmo G. Condorelli Dr. Paolo Bergese Prof. Enrico Dalcanale 《Angewandte Chemie (International ed. in English)》2014,53(35):9183-9188
The direct, clean, and unbiased transduction of molecular recognition into a readable and reproducible response is the biggest challenge associated to the use of synthetic receptors in sensing. All possible solutions demand the mastering of molecular recognition at the solid–liquid interface as prerequisite. The socially relevant issue of screening amine‐based illicit and designer drugs is addressed by nanomechanical recognition at the silicon–water interface. The methylamino moieties of different drugs are all first recognized by a single cavitand receptor through a synergistic set of weak interactions. The peculiar recognition ability of the cavitand is then transferred with high fidelity and robustness on silicon microcantilevers and harnessed to realize a nanomechanical device for label‐free detection of these drugs in water. 相似文献
207.
Synthesis,characterization and assessment of the cytotoxic activity of Cu(II), Fe(III) and Mn(III) complexes of camphoric acid‐derived salen ligands 下载免费PDF全文
Dina Murtinho Zênis N. da Rocha Ana Salomé Pires Roberto P. Jiménez Ana Margarida Abrantes Mafalda Laranjo Ana Catarina Mamede João Eduardo Casalta‐Lopes Maria Filomena Botelho Alberto A. C. C. Pais Sandra C. C. Nunes Hugh D. Burrows Telma Costa M. Elisa Silva Serra 《应用有机金属化学》2015,29(7):425-432
Novel Cu(II), Fe(III) and Mn(III) salen‐type metal complexes from (1R,3S)‐N,N′‐bis[salicylidene]‐1,3‐diamino‐1,2,2‐trimethylcyclopentane were synthesized and screened for their in vitro cytotoxic activity against three human cancer cell lines: melanoma, colorectal and breast. In vitro experiments carried out with the three metal complexes show that the copper complex exhibits the highest cytotoxic activity towards all cell lines studied, presenting IC50 values of 3.32–6.71 μM. A significant improvement in the anti‐proliferative effect, by 20‐fold, is observed with this complex when compared with conventional chemotherapy. The relationship between structure, redox characteristics and biological activity in human cancer cell lines was evaluated for the most efficient Cu(II) complex and associated with theoretical calculations. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
208.
Different calibration methods have been applied for the determination of the Hydroxyl Number in polyester resins, namely Partial Least Squares (PLS), Principal Component Regression (PCR), Ordinary Least Squares with selection of the variables by genetic algorithm (OLS-GEN) and back-propagation Artificial Neural Networks (BP-ANN). The predictive ability of the regression models was estimated by splitting the dataset in training and test sets by application of the Kohonen self-organising maps. The linear methods (OLS-GEN, PLS and PCR) showed comparable results while artificial neural networks provided the best results both in fitting and prediction. 相似文献
209.
Meritxell Cortés Elvira Gómez Elisa Vallés 《Journal of Solid State Electrochemistry》2010,14(12):2225-2233
Platinum-rich CoPt films have been electrodeposited with the aim of preparing hard magnetic films on silicon-based substrates
without the need for subsequent annealing. Electrodeposition conditions have permitted the crystalline structure of the films
to be controlled. Pt percentages of up to 60–65 wt.% have been attained while maintaining the hexagonal Co phase, leading
to CoPt films with moderate coercivity and good corrosion resistance. However, when low deposition potentials were used, CoPt
films with higher Pt percentages were obtained, but in this case, the films exhibited an fcc structure, having lower coercivity
and less corrosion resistance. The presence of hypophosphite in the solution limited the platinum percentage in the deposited
CoPtP films, but an hexagonal close-packed (hcp) structure was always observed in this case. The incorporation of P into the
deposits led to increases in both the coercivity of the films and the corrosion resistance of the coatings, with respect to
pure CoPt. The highest coercivity was obtained for hcp CoPtP deposits with 40 wt.% of Pt. 相似文献
210.
Analysis of wine phenolics by high-performance liquid chromatography using a monolithic type column 总被引:1,自引:0,他引:1
Castellari M Sartini E Fabiani A Arfelli G Amati A 《Journal of chromatography. A》2002,960(1-2):221-227
A polyacrylamide gel crosslinked with allyl-β-cyclodextrin can be used repeatedly for several weeks for the separation of DNA fragments, since bubbles are not generated during a run. Allyl-β-cyclodextrin can easily be synthesized in one step from allylglycidylether and β-cyclodextrin. The plate numbers for DNA fragments, up to about 1500 bp, are high: for the separation of pBR322/HaeIII fragments they were in the range 450 000–1 600 000 m−1. The resolution was almost independent of the concentration of the crosslinker (allyl-β-cyclodextrin) — in sharp contrast to gels crosslinked with N,N′-methylenebisacrylamide. 相似文献