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21.
Fernando Godoy Alejandra Gómez A. Hugo Klahn 《Journal of organometallic chemistry》2010,695(3):346-4353
The fulvene complexes [(η6-C5Me4CH2)Re(CO)2(R)] (1a, RI; 1b, RC6F5) react at the exocyclic methylene carbon with a vinylmagnesium bromide solution to produce the anionic species [(η5-C5Me4CH2CHCH2)Re(CO)2(R)]−. Protonation with HCl at 0 °C produces the hydride complexes [trans-(η5-C5Me4CH2CHCH2)Re(CO)2(R)(H)] (2a, RI; 2b, RC6F5). Thermolysis of an hexane solution of the iodo-hydride (2a) under a CO atmosphere yields the complex [(η5-C5Me4CH2CHCH2)Re(CO)3] (3) and [Re(CO)5I] as by-product. Thermolysis of 2b produced three new products, mainly the chelated complex [(η5:η2-C5Me4CH2CHCH2)Re(CO)2] (4) and complex 3, with a non-coordinated olefin group, in moderated yield, and traces of [Re(CO)5(C6F5)]. Thermolysis of an hexane solution of 2 in presence of an excess of PMe3, afforded the phosphine derivative [(η5-C5Me4CH2CHCH2)Re(CO)2(PMe3)] (5). All the complexes were characterized by IR, 1H, 13C and 31P NMR spectroscopies and mass spectrometry. The molecular structure of 4 has also been determined. The molecule exhibits a formal three-legged piano-stool structure, with two CO groups, and the third position corresponding to the η2-coordination of the propenyl side arm of the η5-C5Me4 ring. 相似文献
22.
Elhabiri M Siri O Sornosa-Tent A Albrecht-Gary AM Braunstein P 《Chemistry (Weinheim an der Bergstrasse, Germany)》2004,10(1):134-141
We present a detailed study on the acid-base behaviour of a family of "potentially antiaromatic" p-benzoquinonediimine ligands. These 12pi electron molecules can be considered as constituted of two chemically connected but electronically not conjugated 6pi-electron subunits. Upon successive protonation, "mono" and "double" cyanine-type chromophores are generated in solution and allow a precise and sensitive spectrophotometric detection. These molecules represent a new class of tunable quinones whose electronic and structural properties can be triggered by proton input, as established by a complete physico-chemical study involving a combination of potentiometric and spectrophotometric methods (absorption and emission). 相似文献
23.
Synthesis, characterization and radiolytic properties of bis(oxalato)borate containing ionic liquids
Sharon I. Lall-Ramnarine Alejandra Castano Gopal Subramaniam Marie F. Thomas James F. Wishart 《Radiation Physics and Chemistry》2009,78(12):1120-1125
Previously unreported bis(oxalato)borate (BOB) ionic liquids (ILs) containing imidazolium, pyridinium, and pyrrolidinium cations were prepared from the corresponding halide salts by reaction with sodium bis(oxalato)borate (NaBOB), and their properties are reported. Pulse radiolysis experiments revealed that the BOB anion scavenges solvated electrons with rate constants of 3×108 M−1 s−1 in the ionic liquid C4mpyrr NTf2 and 2.8×107 M−1 s−1 in water. This reactivity indicates that BOB ILs may be too sensitive to be used as neat solvents for nuclear separations processes in high radiation fields but may still be useful for preventing criticality while processing relatively “cold” fissile actinides. 相似文献
24.
Reverdito Ana María García Mariano Hernán Salerno Alejandra Locani Oscar Alberto Perillo Isabel Amalia 《平面色谱法杂志一现代薄层色谱法》2007,20(3):227-230
JPC – Journal of Planar Chromatography – Modern TLC - When the components of a reaction mixture cannot be quantified by UV-visible spectrophotometry, because the λmax values of... 相似文献
25.
Palacios D Wladimirsky A D'Antonio MC González-Baró AC Baran EJ 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,79(5):1145-1148
The infrared and Raman spectra of Na2Cu(C2O4)(2)·2H2O, K2Cu(C2O4)(2)·2H2O and (NH4)2Cu(C2O4)(2)·2H2O were recorded and briefly discussed on the basis of their structural peculiarities and by comparison with the vibrational spectra of other metallic oxalates. 相似文献
26.
Ramírez-López P de la Torre MC Asenjo M Ramírez-Castellanos J González-Calbet JM Rodríguez-Gimeno A de Arellano CR Sierra MA 《Chemical communications (Cambridge, England)》2011,47(37):10281-10283
Reported herein is the discovery of a novel family of "clicked" estradiol-based LMWGs whose gelation ability highly depends on the gelator symmetry. These LMWGs that gel different organic solvents in the presence of H(2)O even at concentrations as low as 0.04 wt% are readily accessible using "click" chemistry. 相似文献
27.
Marcos Ghislandi Luis Antonio Sanchez de A. Prado Alejandra de la Vega Oyerviedes Hans Wittich Karl Schulte Ana Barros‐Timmons 《Journal of polymer science. Part A, Polymer chemistry》2008,46(10):3326-3335
Vapor‐grown carbon nanofibers (CNFs) were oxidized and functionalized for atom transfer radical polymerization (ATRP) of tert‐butyl acrylate (t‐BA) from the surface of the CNFs. The materials were characterized by solubility tests, Fourier‐transform infrared (FTIR) spectroscopy, Raman spectroscopy, thermogravimetric analysis (TGA), X‐ray diffraction (XRD), and scanning electron microscopy. The FTIR and electron microscopy results suggest that ATRP process was successfully used to graft poly(tert‐butyl acrylate) (poly(t‐BA)) chains from the surface of the fibers. Raman results strongly indicate the partial degradation of the graphitic layer of CNFs because of the chemical treatments. TGA results suggest that the presence of poly(t‐BA) leads to a decrease of the initial degradation temperature of the fibers. XRD and electron microscopy results indicate that the microstructure of fibers was not destroyed because of the oxidation and functionalization processes. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3326–3335, 2008 相似文献
28.
The cycloaddition reactions of 9-substituted anthracenes and levoglucosenone were investigated under microwave irradiation and conventional heating conditions. Considering time, yields, and regioselectivity, microwave technology has proven to be an ideal tool to achieve this chemical transformation. [reaction: see text]. 相似文献
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