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排序方式： 共有732条查询结果，搜索用时 15 毫秒
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Dr. Annalisa Mancini Dr. M. Carla Aragoni Dr. Neil Bricklebank Dr. Carlo Castellano Prof. Francesco Demartin Prof. Francesco Isaia Prof. Vito Lippolis Dr. Anna Pintus Dr. Massimiliano Arca 《化学:亚洲杂志》2013,8(3):639-647
The reactions of 4,5,6,7‐tetrathiocino‐[1,2‐b:3,4‐b′]‐1,3,8,10‐tetrasubstituted‐diimidazolyl‐2,9‐dithiones (R2,R′2‐todit; 1 : R=R′=Et; 2 : R=R′=Ph; 3 : R=Et, R′=Ph) with Br2 exclusively afforded 1:1 and 1:2 “T‐shaped” adducts, as established by FT‐Raman spectroscopy and single‐crystal X‐ray diffraction in the case of complex 1? 2 Br2. On the other hand, the reactions of compounds 1 – 3 with molecular I2 provided charge‐transfer (CT) “spoke” adducts, among which the solvated species 3? 2 I2 ? (1?x)I2 ? x CH2Cl2 (x=0.94) and ( 3 )2 ? 7 I2 ? x CH2Cl2, (x=0.66) were structurally characterized. The nature of all of the reaction products was elucidated based on elemental analysis and FT‐Raman spectroscopy and supported by theoretical calculations at the DFT level. 相似文献
94.
Massimiliano Aschi Mark Brnstrup Martin Diefenbach Jeremy N. Harvey Detlef Schrder Helmut Schwarz 《Angewandte Chemie (International ed. in English)》1998,37(6):829-832
What exactly are the elementary steps in the Pt-catalyzed coupling of methane and ammonia (Degussa process) shown on the right? Mass spectrometry and ab initio theory have been used to probe the mechanistic details of this technically important synthesis of hydrogen cyanide. 相似文献
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96.
Wind M Gebhardt K Grunwald H Spickermann J Donzelli M Kellenberger L Muller M Fullhardt P Schmitt-Hoffmann A Schleimer M 《Rapid communications in mass spectrometry : RCM》2007,21(7):1093-1099
The in vitro metabolic pattern of BAL19403, a novel macrolide antibiotic, was investigated by capillary liquid chromatography/quadrupole time-of-flight mass spectrometry (LC/QTOF-MS) in incubations with human microsomes. For the elucidation of the metabolic pathway, BAL19403 labeled with four deuterium atoms (D4) was used, and detection of metabolites performed using mixtures of the unlabeled (H4) BAL19403 and its D4 analogue (1:1) as substrate. All metabolites appeared with similar chromatographic behavior. MS/MS spectra of BAL19403 and its metabolites are dominated by non-informative fragment ions. Therefore, the structure of the metabolites was elucidated mainly by accurate mass measurements with subsequent proposals of elemental compositions. Main biotransformations were N-demethylation, lactone ring hydrolysis, and oxidation. Additionally, N-dealkylation of the aromatic moiety was identified. This dealkylation results not only in formation of an aldehyde, according to the classical pathway, but also in formation of the corresponding alcohol and carboxylic acid. Final elucidation of their structures was possible, since this dealkylation takes place vicinal to the deuterium-labeled part of BAL19403 and interferes with D/H exchange. The degree of D/H exchange, determined by analysis of the metabolite isotopic pattern, was used to elucidate the adjacent functional group. 相似文献
97.
Crotti S Stella L Munari I Massaccesi F Cotarca L Forcato M Traldi P 《Journal of mass spectrometry : JMS》2007,42(12):1562-1568
The Claisen rearrangement is a well-known process occurring in condensed phase. In the gas-phase protonated allyl phenyl ethers, propargyl phenyl ethers, and N-allyl aniline produced by positive ion chemical ionization undergo Claisen rearrangement. This reaction has been observed even in the case of odd-electron molecular ions. Phenyl allenyl ether molecular ions actually undergo Claisen rearrangement, producing intense [M - CO](+*) ions. In this investigation, the behavior of protonated benzyloxy indole and some of its derivatives, obtained in electrospray conditions, is described. Low-energy MS/MS experiments carried out on [M + H](+) species show CO loss and an unexpected water loss: both can be justified only by the occurrence of Claisen rearrangement. Deuterium labeling experiments confirm this mechanism. The influence of different substituents in the indole moiety is discussed. 相似文献
98.
Massimiliano Boccia Vincenzo Liuzzo Andrea Pucci Piero Narducci Giacomo Ruggeri 《Macromolecular Symposia》2006,235(1):143-151
Summary: Several salicylaldiminate M(II) complexes of Nickel, Copper and Cobalt have been prepared and mixed with ethylene based polymers in order to prepare new composite materials with interesting morphological and optical properties by profiting of the presence of alkyl chains and push-pull substituents connected to the ligand structure. The phase dispersion behaviour of the binary films has been studied by scanning electron microscopy (SEM) and x-ray microanalysis, whereas the optical properties of the composite samples have been evaluated by UV-vis and fluorescence spectroscopy. The results in absorption have been analysed in terms of the anisotropy induced by the mechanical orientation of the polymer matrix and by the role of the metal centre according to the different strength of the complexes transition dipole moment. The luminescence behaviour have been discussed in terms of potential developments aimed at preparing polymeric supported Schiff base ligands for metal ions sensor applications. 相似文献
99.
Bystrenova E Facchini M Cavallini M Cacace MG Biscarini F 《Angewandte Chemie (International ed. in English)》2006,45(29):4779-4782
100.
Summary Cobalt(II) can be determined in 0.1 mol/l Na3citrate + 0.1 mol/l NH4Cl + 0.08% dimethylglyoxime as supporting electrolyte in the presence of a 50 000-fold excess of zinc by differential pulse polarography. The limit of determination is 4.2×10–5 mol/l Co (2.5 mg/l). Linear calibration curves are obtained within the range of 1×10–7 to 5×10–6 mol/l cobalt without zinc and in the presence of 5×10–3 mol/l Zn. The analytical method developed is suitable for the determination of cobalt in zinc plant solutions.
Cobaltbestimmung in Gegenwart hoher Zinkkonzentrationen mit Hilfe der Differential-Puls-Polarographie相似文献