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Alkali‐Metal Trichloroacetates for Dichloromethylenation of Fullerenes: Nucleophilic Addition‐Substitution Route 下载免费PDF全文
Marina G. Apenova Vladimir A. Akhmetov Nikita M. Belov Dr. Alexey A. Goryunkov Dr. Ilya N. Ioffe Dr. Natalia S. Lukonina Dr. Vitaliy Yu. Markov Prof. Dr. Lev N. Sidorov 《化学:亚洲杂志》2014,9(3):915-923
The first experimental evidence that fullerenes react with alkali‐metal trichloroacetates through a nucleophilic addition‐substitution route, yielding dichloromethylenefullerenes as the final products, is reported. The intermediates, C60(CCl3)? and C70(CCl3)? anions, have been isolated in their protonated forms as ortho‐C60(CCl3)H, as well as three ortho and one para isomer of C70(CCl3)H. The structures were unambiguously determined by means of 1H, 13C, and 1H–13C HMBC NMR spectroscopy along with UV/Vis spectroscopy. The observed regiochemistry was analyzed with the aid of quantum chemical calculations. Conversion of the protonated compounds into the [6,6]‐closed C60/70(CCl2) cycloadducts under basic conditions can be effected only for the ortho isomers, whereas para‐C70(CCl3)H decomposes back into pristine C70. 相似文献
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Plekan O Feyer V Richter R Moise A Coreno M Prince KC Zaytseva IL Moskovskaya TE Soshnikov DY Trofimov AB 《The journal of physical chemistry. A》2012,116(23):5653-5664
The electronic structures of the purine derivatives xanthine, hypoxanthine and caffeine have been investigated in the gas phase using C, N, and O 1s X-ray photoemission (XPS) and near edge X-ray absorption fine structure (NEXAFS) spectroscopy. The results have been interpreted by means of ab initio calculations using the third-order algebraic-diagrammatic construction (ADC(3)) method for the one-particle Green's function and the second-order ADC method (ADC(2)) for the polarization propagator. The carbon, nitrogen and oxygen K-edge NEXAFS spectra of xanthine and caffeine are very similar, since the molecules differ only by substitution of three hydrogen atoms by methyl groups. For hypoxanthine, the electronic structure and spectra differ considerably from xanthine as the purine ring is more highly conjugated, and there is one less oxo group. Effects due to oxo-hydroxy tautomerism were not observed. However, the two oxo tautomeric forms of hypoxanthine oxo-N(9)-H and oxo-N(7)-H are populated in the gas phase, and the C 1s spectra can be simulated only by taking account of these two tautomers, with appropriate Boltzmann population ratios which we have also calculated. For xanthine and caffeine, single tautomeric forms were observed. 相似文献
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Aleksey.I.Aleksandrov Ivan A.Aleksandrov Vitaliy G.Shevchenko Aleksandr N.Ozerin 《高分子科学》2021,39(5):601-609
Rheological explosion in polymers under uniaxial compression in an open volume occurs at the end of continuous rapid plastic deformation after several stages of creep. Two types of polymers were chosen for this study: brittle glassy amorphous polystyrene and thermoplastic semi-crystalline polypropylene. Electric pulses were detected during explosion, and their spectra were analyzed with two models.X-ray diffraction methods were used to investigate changes in the structure and morphology of polymers during deformation and rheological explosion. The pores appear in polymer in this process, and their shape and size distribution were derived from X-ray experiments. The main reason for the formation of pores in polymer samples in rheological explosion experiments is the intense microshifts in the polymer volume under the action of high applied pressure. 相似文献
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Iulia Cojocariu Dr. Silvia Carlotto Henning Maximilian Sturmeit Dr. Giovanni Zamborlini Prof. Mirko Cinchetti Dr. Albano Cossaro Dr. Alberto Verdini Dr. Luca Floreano Dr. Matteo Jugovac Prof. Peter Puschnig Dr. Cinthia Piamonteze Prof. Maurizio Casarin Dr. Vitaliy Feyer Prof. Claus Michael Schneider 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(10):3526-3535
Due to its unique magnetic properties offered by the open-shell electronic structure of the central metal ion, and for being an effective catalyst in a wide variety of reactions, iron phthalocyanine has drawn significant interest from the scientific community. Nevertheless, upon surface deposition, the magnetic properties of the molecular layer can be significantly affected by the coupling occurring at the interface, and the more reactive the surface, the stronger is the impact on the spin state. Here, we show that on Cu(100), indeed, the strong hybridization between the Fe d-states of FePc and the sp-band of the copper substrate modifies the charge distribution in the molecule, significantly influencing the magnetic properties of the iron ion. The FeII ion is stabilized in the low singlet spin state (S=0), leading to the complete quenching of the molecule magnetic moment. By exploiting the FePc/Cu(100) interface, we demonstrate that NO2 dissociation can be used to gradually change the magnetic properties of the iron ion, by trimming the gas dosage. For lower doses, the FePc film is decoupled from the copper substrate, restoring the gas phase triplet spin state (S=1). A higher dose induces the transition from ferrous to ferric phthalocyanine, in its intermediate spin state, with enhanced magnetic moment due to the interaction with the atomic ligands. Remarkably, in this way, three different spin configurations have been observed within the same metalorganic/metal interface by exposing it to different doses of NO2 at room temperature. 相似文献