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91.
Dr. Antonio Zucca Dr. Luca Maidich Laura Canu Dr. Giacomo L. Petretto Prof. Sergio Stoccoro Prof. Maria Agostina Cinellu Dr. Guy J. Clarkson Dr. Jonathan P. Rourke 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(18):5501-5510
Rollover cyclometalation involves bidentate heterocyclic donors, unusually acting as cyclometalated ligands. The resulting products, possessing a free donor atom, react differently from the classical cyclometalated complexes. Taking advantage of a “rollover”/“retro‐rollover” reaction sequence, a succession of oxidative addition and reductive elimination in a series of platinum(II) complexes [Pt(N,C)(Me)(PR3)] resulted in a rare C(sp2)?C(sp3) bond formation to give the bidentate nitrogen ligands 3‐methyl‐2,2′‐bipyridine, 3,6‐dimethyl‐2,2′‐bipyridine, and 3‐methyl‐2‐(2′‐pyridyl)‐quinoline, which were isolated and characterized. The nature of the phosphane PR3 is essential to the outcome of the reaction. This route constitutes a new method for the activation and functionalization of C?H bond in the C(3) position of bidentate heterocyclic compounds, a position usually difficult to functionalize. 相似文献
92.
Combining Complementary Ligands into one Framework for the Construction of a Ferromagnetically Coupled [MnIII12] Wheel 下载免费PDF全文
Dr. Sergio Sanz Jamie M. Frost Thayalan Rajeshkumar Dr. Scott J. Dalgarno Dr. Gopalan Rajaraman Dr. Wolfgang Wernsdorfer Prof. Jürgen Schnack Dr. Paul. J. Lusby Prof. Euan K. Brechin 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(11):3010-3013
Phenolic oxime and diethanolamine moieties have been combined into one organic framework, resulting in the formation of a novel ligand type that can be employed to construct a rare and unusual dodecametallic Mn wheel, within which nearest neighbours are coupled ferromagnetically. 相似文献
93.
Highly Enantioselective Construction of Tricyclic Derivatives by the Desymmetrization of Cyclohexadienones 下载免费PDF全文
Sandra del Pozo Dr. Alejandro Parra Dr. Sergio Díaz‐Tendero Dr. Rubén Mas‐Ballesté Dr. Silvia Cabrera Dr. José Alemán 《Angewandte Chemie (International ed. in English)》2014,53(31):8184-8189
The asymmetric synthesis of tricyclic compounds by the desymmetrization of cyclohexadienones is presented. The reaction tolerated a large variety of substituents at different positions of the cyclohexadienone, and heterocyclic rings of different sizes were accessible. Density functional theory calculations showed that the reaction proceeds through an asynchronous [4+2] cycloaddition. 相似文献
94.
Barbara Perez Gonçalves Silva Rodrigo Oliveira Marcon Sergio Brochsztain 《Journal of inclusion phenomena and macrocyclic chemistry》2010,68(3-4):313-322
Fluorescence spectroscopy was used to characterize inclusion compounds between 4-amino-1,8-naphthalimides (ANI) derivatives and different cyclodextrins (CDs). The ANI derivatives employed were N-(12-aminododecyl)-4-amino-1,8-naphthalimide (mono-C12ANI) and N,N′-(1,12-dodecanediyl)bis-4-amino-1,8-naphthalimide (bis-C12ANI). The CDs used here were α-CD, β-CD, γ-CD, HP-α-CD, HP-β-CD and HP-γ-CD. The presence of CDs resulted in pronounced blue-shifts in the emission spectra of the ANI derivatives, with increases in emission intensity. This behavior was parallel to that observed for the dyes in apolar solvents, indicating that inclusion complexes were formed between the ANI and the CDs. Mono-C12ANI formed inclusion complexes of 1:1 stoichiometry with all the CDs studied. Complexes with the larger CDs (HP-β-CD, HP-γ-CD and γ-CD) were formed by inclusion of the chromophoric ANI ring system, whereas the smaller CDs (α-CD, HP-α-CD and β-CD) formed complexes with mono-C12ANI by inclusion of the dodecyl chain. Bis-C12ANI formed inclusion complexes of 1:2 stoichiometry with HP-β-CD, HP-γ-CD and γ-CD, but did not form inclusion complexes with α-CD, HP-α-CD and β-CD. The data were treated in the case of the large CDs using a Benesi-Hildebrand like equation, giving the following equilibrium constants: mono-C12ANI:HP-β-CD (K 11 = 50 M?1), mono-C12ANI:HP-γ-CD (K 11 = 180 M?1), bis-C12ANI:HP-β-CD (K 12 = 146 M?2), bis-C12ANI:HP-γ-CD (K 12 = 280 M?2). 相似文献
95.
The feasibility of microwave-accelerated derivatization for capillary electrophoresis (CE) with laser-induced fluorescence (LIF) detection was evaluated. The derivatization reaction was performed in a domestic microwave oven. Histidine (His), 1-methylhistidine (1-MH) and 3-methylhistidine (3-MH) were selected as test analytes and fluorescein isothiocyanate (FITC) was chosen as a fluorescent derivatizing reagent. Parameters that may affect the derivatization reaction and/or subsequent CE separation were systematically investigated. Under optimized conditions, the microwave-accelerated derivatization reaction was successfully completed within 150 s, compared to 4-24 h in a conventional water-bath derivatization process. This will remarkably reduce the overall analysis time and increase sample throughput of CE-LIF. The detection limits of this method were found to be 0.023 ng/mL for His, 0.023 ng/mL for 1-MH, and 0.034 ng/mL for 3-MH, respectively, comparable to those obtained using traditional derivatization protocols. The proposed method was characterized in terms of precision, linearity, accuracy and successfully applied for rapid and sensitive determination of these analytes in human urine. 相似文献
96.
Fernando C. Moraes Lucia H. Mascaro Sergio A. S. Machado Christopher M. A. Brett 《Electroanalysis》2010,22(14):1586-1591
A copper phthalocyanine/multiwalled carbon nanotube film‐modified glassy carbon electrode has been used for the determination of the herbicide glyphosate (Gly) at ?50 mV vs. SCE by electrochemical oxidation using differential pulse voltammetry (DPV). Cyclic voltammetry and electrochemical impedance spectroscopy showed that Gly is adsorbed on the metallic centre of the copper phthalocyanine molecule, with formation of Gly‐copper ion complexes. An analytical method was developed using DPV in pH 7.4 phosphate buffer solution, without any pretreatment steps: Gly was determined in the concentration range of 0.83–9.90 μmol L?1, with detection limit 12.2 nmol L?1 (2.02 μg L?1). 相似文献
97.
Changlong Wang Dr. Roberto Ciganda Dr. Lionel Salmon Dr. Danijela Gregurec Dr. Joseba Irigoyen Dr. Sergio Moya Dr. Jaime Ruiz Prof. Didier Astruc 《Angewandte Chemie (International ed. in English)》2016,55(9):3091-3095
A ligand design is proposed for transition metal nanoparticle (TMNP) catalysts in aqueous solution. Thus, a tris(triazolyl)‐polyethylene glycol (tris‐trz‐PEG) amphiphilic ligand, 2 , is used for the synthesis of very small TMNPs with Fe, Co, Ni, Cu, Ru, Pd, Ag, Pt, and Au. These TMNP‐ 2 catalysts were evaluated and compared for the model 4‐nitrophenol reduction, and proved to be extremely efficient. High catalytic efficiencies involving the use of only a few ppm metal of PdNPs, RuNPs, and CuNPs were also exemplified in Suzuki–Miyaura, transfer hydrogenation, and click reactions, respectively. 相似文献
98.
Cusmin P Salud J López DO de la Fuente MR Diez S Pérez-Jubindo MA Barrio M Tamarit JL 《The journal of physical chemistry. B》2006,110(51):26194-26203
The metastable phase diagram of the two-component system heptyloxycyanobiphenyl (7OCB)+nonyloxycyanobiphenyl (9OCB) was determined by means of modulated differential scanning calorimetry (MDSC) and optical microscopy measurements. It was experimentally established that the 7OCB+9OCB two-component system exhibits a monotropic re-entrant nematic behavior. A complete quantitative thermodynamic analysis, through Oonk's equal G analysis, was performed, allowing for the calculation of the monotropic re-entrant behavior and the prediction of two tricritical points, one of them experimentally accessible for the SmAd-to-N transition and the other non-experimentally accessible for the RN-to-SmAd transition. From specific-heat measurements, latent heats were obtained for those mixtures displaying a first-order SmAd-to-N transition. Additionally, for some mixtures, the specific-heat critical exponents (alpha), through the second-order SmAd-to-N transition, were obtained. Both batches of data enable us to access to the experimental tricritical temperature for the SmAd-to-N transition. 相似文献
99.
Electrochemical oxidation of organic pollutants for the wastewater treatment: direct and indirect processes 总被引:5,自引:0,他引:5
In recent years, there has been increasing interest in finding innovative solutions for the efficient removal of contaminants from water, soil and air. The present tutorial review summarizes the results of an extensive selection of papers dealing with electrochemical oxidation, which is proposed as an alternative for treating polluted wastes. Both the direct and indirect approaches are considered, and the role of electrode materials is discussed together with that of other experimental parameters. Apart from discussing the possibility of removing selected contaminants from water using different anodes, efficiency rates for pollutant removal have been collected, the dependence of these rates on operational conditions advantages and disadvantages determining the further full-scale commercial application. 相似文献
100.