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91.
A series of fluorinated fullerene-fused 1,3-dioxolanes have been facilely and efficiently synthesized in the presence of easily available LiClO4·3H2O. The influences of the number of fluoro-substituents and their positions linked to the phenyl ring on the isolated yield of fullerene-fused 1,3-dioxolanes have been studied in detail. Based on reaction facts, a possible reaction mechanism for the formation of fluorinated fullerene-fused 1,3-dioxolanes has been proposed. Furthermore, detailed ultraviolet absorption spectra, fluorescence emission spectra, and cyclic voltammogram further explain the optical properties and electronic transmission capabilities of the products. 相似文献
92.
93.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(4):992-995
Under high pressure, some materials form electrides, with valence electrons separated from all atoms and occupying interstitial regions. This is often accompanied by semiconducting or insulating behavior. The interstitial quasiatoms (ISQ) that characterize some high pressure electrides have been postulated to show some of the chemical features of atoms, including the potential of forming covalent bonds. It is argued that in the observed high‐pressure semiconducting Li phase (oC40, Aba2), an example of such quasimolecules is realized. The theoretical evaluation of electron density, electron localization function, Wannier orbitals, and bond indices forms the evidence for covalently bonded ISQ pairs in this material. The quasimolecule concept thus provides a simple chemical perspective on the unusual insulating behavior of such materials, complementing the physical picture previously presented where the global crystal symmetry of the system plays the major role. 相似文献
94.
95.
96.
The structure and the depth of the center of a continuous map of a dendrite with a closed countable set of branch points of a finite order are studied. It is proved that the center of that map coincides with the closure of the set of periodic points. It is shown also that for an arbitrary natural number n S 2 there are the dendrite X n with a closed countable set of branch points of a finite order and the continuous map f n : X n M X n with n as the depth of the center. 相似文献
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98.
Ray L. Frost Yunfei Xi Ricardo Scholz Andrés López Fernanda M. Belotti Mário L. S. C. Chaves 《Phosphorus, sulfur, and silicon and the related elements》2013,188(11):1526-1534
Abstract The metal lithium is very important in industry, including lithium batteries. An important source of lithium besides continental brines is granitic pegmatites as in Australia. Lithiophilite is a lithium and manganese phosphate with chemical formula LiMnPO4 and forms a solid solution with triphylite, its Fe analog, and belongs to the triphylite group that includes karenwebberite, natrophilite, and sicklerite. The mineral lithiophilite was characterized by chemical analysis and spectroscopic techniques. The chemical is: Li1.01(Mn0.60, Fe0.41, Mg0.01, Ca0.01)(PO4)0.99 and corresponds to an intermediate member of the triphylite-lithiophilite series, with predominance of the lithiophilite member. The mineral lithiophilite is readily characterized by Raman and infrared spectroscopy. 相似文献
99.
Azim Ziyaei Halimjani 《合成通讯》2013,43(17):2271-2276
An efficient and simple method for the reduction of aldehydes, ketones and acid chlorides has been accomplished by using NaBH4–solid LiClO4 in mild conditions at ambient temperature with complete chemoselectivity in reduction of α,β‐unsaturated aldehydes and ketones. The reaction is fast with high yield and simple workup. 相似文献
100.
Lithium carbonate (Li2CO3) and ammonium dihydrogen phosphate (NH4H2PO4) were used for synthesizing lithium diphosphate (Li4P2O7). The purity of the latter compound was checked up by X-ray diffraction. The heat of dissolution of (Li4P2O7) in phosphoric acid solution was measured in a C-80 SETARAM calorimeter. Many dilution and mixing processes in acid solutions of several concentrations (w/w) H3PO4, were also realized in the calorimeter in order to get the standard enthalpy of formation of this product. Two thermochemical cycles were investigated and the obtained values for the enthalpy of formation are: (−3383.4 and −3147) kJ · mol−1. The former one is in better agreement with literature data. 相似文献