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991.
Back Cover: Synthesis and Reactivity of New Functionalized Perfluoroalkylfluorophosphates (Chem. Eur. J. 25/2014) 下载免费PDF全文
992.
Organic–Inorganic Azafullerene‐Gold C59N‐Au Nanohybrid: Synthesis,Characterization, and Properties 下载免费PDF全文
Dr. Georgios Rotas Dr. Marja Niemi Prof. Nikolai V. Tkachenko Sihan Zhao Prof. Hisanori Shinohara Prof. Nikos Tagmatarchis 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(45):14729-14735
Azafullerene (C59N) was functionalized using a Mannich‐type reaction and then subsequently condensed with lipoic acid to yield dithiolane‐modified C59N. In the following step, the extended dithiolane moiety from the C59N core was utilized to decorate the azafullerene sphere with gold nanoparticles (Au NPs). The latter were initially stabilized with dodecanothiol (DT ? Au) and then integrated on azafullerene through a ligand exchange reaction with the dithiolane‐functionalized C59N to produce the C59N/DT ? Au nanohybrid. The nanohybrid was fully characterized by spectroscopy and microscopy, revealing the formation of spherical nanoparticles with a diameter in the range of 2–5 nm, as imaged by HR‐TEM. In the electronic absorption spectrum of C59N/DT ? Au nanohybrid, the characteristic surface plasmon band (SPB) of Au NPs was observed, however, it was redshifted compared with that of DT ? Au. The redshift of the SPB is indicative of closer interparticle proximity of Au NPs, in accordance with the formation of aggregated NPs as observed by TEM, in C59N/DT ? Au nanohybrid. Excited‐state interactions in C59N/DT ? Au were probed by photoluminescence assays. It was found that the weak emission of C59N at 819 nm was blueshifted by 14 nm in C59N/DT ? Au, but was stronger in intensity, thus suggesting energy transfer to C59N, within the organic–inorganic C59N/DT ? Au nanohybrid. Finally, with the aid of pump–probe measurements and transient absorption spectroscopy, the formation of the singlet excited state of C59N was identified. 相似文献
993.
A Direct,Modular, and Efficient Construction of the PCP Structural Motif through Coupling of Manganese Carbyne Complexes with Phosphines 下载免费PDF全文
Dr. Dmitry A. Valyaev Stéphanie Bastin Kamil I. Utegenov Noël Lugan Guy Lavigne Prof. Dr. Nikolai A. Ustynyuk 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(8):2175-2178
Easily available carbyne complexes of manganese were used as a source of carbyne fragments in an unconventional synthesis of backbone‐substituted diphosphinomethanes and cyclic P‐ylides upon coupling with secondary or tertiary phosphines, respectively, followed by demetalation under mild conditions. 相似文献
994.
Johannes Landmann Jan A. P. Sprenger Michael Hailmann Vera Bernhardt‐Pitchougina Helge Willner Nikolai Ignat'ev Eduard Bernhardt Maik Finze 《Angewandte Chemie (International ed. in English)》2015,54(38):11259-11264
Diborane(6) dianions with substituents that are bonded to boron via carbon are very reactive and therefore only a few examples are known. Diborane(6) derivatives are the simplest catenated boron compounds with an electron‐precise B–B σ‐bond that are of fundamental interest and of relevance for material applications. The homoleptic hexacyanodiborane(6) dianion [B2(CN)6]2− that is chemically very robust is reported. The dianion is air‐stable and resistant against boiling water and anhydrous hydrogen fluoride. Its salts are thermally highly stable, for example, decomposition of (H3O)2[B2(CN)6] starts at 200 °C. The [B2(CN)6]2− dianion is readily accessible starting from 1) B(CN)32− and an oxidant, 2) [BF(CN)3]− and a reductant, or 3) by the reaction of B(CN)32− with [BHal(CN)3]− (Hal=F, Br). The latter reaction was found to proceed via a triply negatively charged transition state according to an SN2 mechanism. 相似文献
995.
Fourier spectroscopy, one of the most precise spectrometry methods in light optics, has been realized in the past years with electron waves by including a crossed-field analyzer (Wien filter) as a wave packet shifting device into a biprism interferometer. To fully exploit the high precision of this method of determining the energy spectrum, higher order corrections stemming from the Wien filter's focusing action are necessary in the evaluation of the measurement. We show that these can be taken into account by using a transformation variable being proportional to the quotient of electric field strength of the Wien capacitor over fringe spacing. Finally, we make some remarks about the possibility of interference of inelastically scattered electrons. 相似文献
996.
Mehdi Mardanian Alena A. Nevar Nikolai V. Tarasenko 《Applied Physics A: Materials Science & Processing》2013,112(2):437-442
In this paper, we report a simple and low-cost technique for fabrication of silicon nanoparticles via electrical spark discharge between two plane silicon electrodes immersed in deionized water (DI). The pulsed spark discharge with the peak current of 60 A and a duration of a single discharge pulse of 60 μs was used in our experiment. The structure, morphology, and average size of the resulting nanoparticles were characterized by means of X-Ray Diffraction (XRD), Raman spectroscopy and transmission electron microscopy (TEM). TEM images illustrated nearly spherical and isolated Si nanoparticles with diameters in the 3–8 nm range. The Raman peaks of the samples were shifted to the lower wave numbers in comparison to this of bulk crystalline silicon indicating the existence of tiny particles. The optical absorption spectrum of the nanoparticles was measured in the violet–visible (UV–Vis) spectral region. By measuring of the band gap we could estimate the average size of the prepared particles. The silicon nanoparticles synthesized exhibited a photoluminescence (PL) band in the violet-blue region with a double peak at around 417 and 439 nm. It can be attributed to oxide-related defects on the surface of silicon nanoparticles, which can act as the radiative centers for the electron-hole pair recombination. 相似文献
997.
998.
Anatoly N Trukhin Tatyana I Dyuzheva Nikolai A Bendeliani 《Solid State Communications》2004,131(1):1-5
The optical absorption spectra of the small mono-crystals samples of stishovite and coesite were studied at first. The intrinsic absorption threshold of stishovite is determined at 8.75 eV, being probably, highest in the family of different crystalline polymorph modifications of silicon dioxide. The absorption spectrum of stishovite is independent of temperature (studied in the range 290-450 K). The intrinsic absorption threshold of coesite mono-crystal situated near 8.6 eV at 293 K, coincides within experimental errors with that of α-quartz crystal, and depends on temperature, as used to be for the tetrahedron structured silicon dioxide crystalline modifications. A broad absorption band with a first spread maximum near 7.6 eV sides with intrinsic absorption threshold was found in the stishovite mono-crystal sample. Its low intensity (about 10 cm−1) in an as-received sample shows on a defective nature of this band. No analogous band was detected in the sample of coesite. 相似文献
999.
Nikolai Tyutyulkov Nedko Drebov Fritz Dietz 《Monatshefte für Chemie / Chemical Monthly》2005,21(1):1573-1578
It is shown that the extended Coulson-Rushbrooke-Longuet-Higgins theorem is the structural principle of a class of 1-D polymethine systems with nonbonding MOs and a small HOMO-LUMO gap. From this point of view the structural and spectroscopic properties of a class of pyridocyanine dyes earlier investigated can be interpreted. 相似文献
1000.
Roman S. Borisov Nikolai Yu. Polovkov Vladimir G. Zaikin 《Rapid communications in mass spectrometry : RCM》2009,23(20):3309-3312
A method for end‐group characterization by matrix‐assisted laser desorption/ionization (MALDI) mass spectrometry following preliminary derivatization with N,O‐bis(trimethylsilyl)trifluoroacetamide (BSTFA) and capryloyl chloride is described and applied to poly(alkylene glycol)s. The MALDI mass spectra of the products revealed peaks of sodiated derivative cations, whose shift by the respective increments allowed the determination of the number of end functional groups with active hydrogens. This approach is particularly efficient for the distinction of cyclic and linear dehydration products among minor components. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献