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41.
Raffaello Papadakis Ioanna Deligkiozi Athanase Tsolomitis 《Analytical and bioanalytical chemistry》2010,397(6):2253-2259
This work deals with the design, synthesis, and characterization of a new solvatochromic dye. The intense solvatochromic behavior
of this new synthesized non symmetric viologen was investigated using UV–Vis spectrophotometry. A further purpose was the
study of the interactions between the solvent and solute molecules responsible for the solvatochromism. Several protic and
aprotic solvents were used, and the resulting absorption maxima wavenumbers obtained via UV–Vis spectrophotometry, were correlated
with the solvent polarity parameters, E
T
(30) (Dimroth–Reichardt solvent polarity parameter) and the Gutmann’s donor number (DN) using the biparametric model introduced
by Krygowski and Fawcett. The analysis of the relative contribution of each parameter has clearly shown that the dominating
interaction responsible for the solvatochromic behavior observed is the proton donation by the solute molecules to the solvent
molecules, the latter acting as a Lewis bases. This is an interaction which can be described by DN. Additionally, the good
correlation with the Kamlet–Taft parameter β is in good agreement. 相似文献
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In this work, a new [2]rotaxane consisted of a diazobenzene containing π-conjugated linear compartment, including the 4,4′-bipyridyl moiety and α-cyclodextrin (α-CD) as the macrocyclic compartment, was synthesised with yields of nearly 57% and fully characterised. α-CD easily assembled with the linear compartment and suitable bulky ends (stoppers) in water to give a new [2]rotaxane. The characterisation of this supramolecular compound was accomplished using several spectroscopic techniques such as 1H NMR, 13C NMR and 2D NMR spectroscopy, powder X-ray diffraction, fourier transform infrared spectroscopy, induced circular dichroism and UV–vis spectrophotometry, as well as scanning electron microscopy and Energy Dispersive X-ray. Furthermore, the reversible E–Z photoisomerisation of both [2]rotaxane and its molecular dumbbell was investigated by irradiation with UV light. 相似文献
45.
Raffaello Ferone Viktor Zólyomi Edward McCann Vladimir I. Fal’ko 《Solid State Communications》2011,151(16):1071-1074
We analyze the spectral density of Raman scattering in graphene accompanied by the emission of a pair of LO or LA phonons from the corner of the Brillouin zone. Using a minimal tight-binding model approach, we find that the lineshape of the corresponding Raman signal consists of two peaks with a strongly non-Lorentzian (almost triangular) form with their width and the splitting between the peaks being strongly dependent on the energy of the incoming photon. The asymmetric lineshape is determined by the kinematics of the fully-resonant two-phonon process, and it reflects a strong anisotropy of LO-LA phonons’ dispersion around the Brillouin zone corners. 相似文献
46.
Raffaello Mazzaro Alessandro Boni Dr. Giovanni Valenti Prof. Massimo Marcaccio Prof. Francesco Paolucci Dr. Luca Ortolani Dr. Vittorio Morandi Prof. Paola Ceroni Dr. Giacomo Bergamini 《ChemistryOpen》2015,4(3):268-273
Graphene–metal composites have potential as novel catalysts due to their unique electrical properties. Here, we report the synthesis of a composite material comprised of monodispersed platinum nanoparticles on high-quality graphene obtained by using two different exfoliation techniques. The material, prepared via an easy, low-cost and reproducible procedure, was evaluated as an electrocatalyst for the hydrogen evolution reaction. The turnover frequency at zero overpotential (TOF0 in 0.1 m phosphate buffer, pH 6.8) was determined to be approximately 4600 h−1. This remarkably high value is likely due to the optimal dispersion of the platinum nanoparticles on the graphene substrate, which enables the material to be loaded with only very small amounts of the noble metal (i.e., Pt) despite the very highly active surface. This study provides a new outlook on the design of novel materials for the development of robust and scalable water-splitting devices. 相似文献
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The reaction of phosphorus pentachloride with some 3:5-disubstituted-4-nitrosopyrazoles (dimethyl, diphenyl, methyl phenyl and phenyl carbomethoxy) has been investigated. Formation of a new class of compounds, 1-chloro-4-cyano-2:3-diazabuta-1:3-dienes, is described. By treatment with ammonia and subsequent alkali-induced cyclisation these substances are converted into 5-amino-as-triazines and reactions of the latter have been investigated. 相似文献
49.
Raffaello Lazzaroni Sergio Pucci Sergio Bertozzi Dario Pini 《Journal of organometallic chemistry》1983,247(3):c56-c58
The degree of diastereoselectivity in the rhodium-catalyzed hydroformylation of (+)(R)-1-phenylethyl vinyl ether is much higher than that in the hydroformylation of the related olefin, 4-phenyl-1-pentene. 相似文献
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