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Dr. Oleksandr S. Kanishchev Prof. William R. Dolbier Jr. 《Angewandte Chemie (International ed. in English)》2015,54(1):280-284
Current approaches to prepare SF5‐substituted heterocycles during the synthesis of targeted heterocyclic compounds require the use of SF5‐functionalized aryl or alkyne reagents or SF5Cl as a source of the SF5 functional group. Herein we report that excess oxidative fluorination of 2,2′‐dipyridyl disulfide with a KF/Cl2/MeCN system leads to the formation of thirteen new 2‐pyridylsulfur chlorotetrafluorides (2‐SF4Cl‐pyridines). These molecules are found to undergo further chlorine–fluorine exchange reactions by treatment with silver(I) fluoride enabling ready access to a series of ten new substituted 2‐pyridylsulfur pentafluorides (2‐SF5‐pyridines). This is the first preparatively simple and readily scalable example of the transformation of an existing heterocyclic sulfur functionality to prepare SF5‐substituted heterocycles. 相似文献
24.
Kovalenko OO Brusylovets OA Kinzhybalo V Lis T Brusilovets AI 《Dalton transactions (Cambridge, England : 2003)》2011,40(18):4814-4817
The low-coordinate phosphorus compounds (Me(3)Si)(2)N-P=NSiMe(3), (Me(3)Si)(2)N-P(=S)=N(t)Bu and (Me(3)Si)(2)N-P(=NSiMe(3))(2) react with ((i)PrO)(3)M≡M(O(i)Pr)(3) (M = Mo, W) to form four- and five-membered metallacycles with intact endocyclic or exocyclic M≡M triple bonds. The first four-membered planar metallacycles, containing an M≡M triple bond were obtained in reaction with (Me(3)Si)(2)N-P=NSiMe(3). 相似文献
25.
Solozhenko VL Kurakevych OO Sokolov PS Baranov AN 《The journal of physical chemistry. A》2011,115(17):4354-4358
Kinetics of the wurtzite-to-rock-salt transformation in ZnO has been studied in the 5-7 GPa pressure range at temperatures below the activation of diffusion processes. The detailed analysis of non-isothermal experimental data using the general evolution equation describing the kinetics of direct phase transformations in solids allowed us to study the kinetic particularities of both nucleation and growth of the rock-salt phase in parent wurtzite ZnO. The main rate-limiting processes are thermally activated nucleation (E(N) = 383 kJ mol(-1) at 6.9 GPa) and thermally nonactivated (most probably quasi-martensitic) growth (k(G) = 0.833 min(-1) at 6.9 GPa). The high impact of thermal deactivation of nucleation places has been evidenced in the case of slow heating, which indirectly indicates that the rs-ZnO nucleation places are mainly produced by pressure-induced stresses in the parent phase. 相似文献
26.
Oleksandr O. Kurakevych 《高压研究》2013,33(1):48-52
Novel superhard phases are expected to be found among various high-pressure polymorphs of light element compounds. Besides diamond-like phases, the icosahedral boron-rich solids are of particular interest because they could combine high hardness with advanced electronic and phonon transport properties, lightness, high thermal and chemical stability. Here we review some recent results on high-pressure synthesis of novel boron-rich solids. 相似文献
27.
Prof. Dr. Oleksandr O. Grygorenko Prof. Dr. Rostyslav D. Lampeka Prof. Dr. Valentyn A. Chebanov Prof. Dr. Maksym V. Kovalenko Prof. Dr. Stefan Wuttke 《Chemical record (New York, N.Y.)》2024,24(2):e202400008
In this special issue, we highlight recent advances in chemical research by scientists in Ukraine, as well as by their compatriots and collaborators outside the country. Besides spotlighting their contributions, we see our task in fostering global partnerships and multi-, inter-, and trans-disciplinary collaborations, including much-needed co-funded projects and initiatives. The three decades of the renewed Ukraine independence have seen rather limited integration of Ukrainian (chemical) science into global research communities.[1] At the same time, the recent surge of collaborative science initiatives between European Union (EU) and Ukraine echoes the unfolding steps towards Ukraine's full research participation to the Horizon Europe Program. This recently implemented step opens enormous possibilities for Ukrainian researchers to apply for diverse EU research grants. Moreover, a number of journal special issues and collections were launched to highlight Ukrainian chemistry (i. e., by Chemistry of Heterocyclic Compounds[2] and ChemistrySelect[3]). Other scientific initiatives include ‘European Chemistry School for Ukrainians’[4] and ‘Kharkiv Chemical Seminar’[5] as voluntary projects aimed at engaging Ukrainian scientists into European and international chemical research. 相似文献
28.
Irina O. Zhuravel Oleg V. Zaremba Oleksandr S. Detistov Svitlana S. Kovalenko Valentin P. Chernykh 《合成通讯》2013,43(21):3778-3784
New 5-hydroxymethyl-8-methyl-3-(3-aryl-[1,2,4]oxadiazol-5-yl)-2H-pyrano-[2,3-c]pyridin-2-ones and their esters were synthesized. The structure of obtained compounds was determined through a complete 1H NMR analysis. 相似文献
29.
Li F Buchnev O Cheon CI Glushchenko A Reshetnyak V Reznikov Y Sluckin TJ West JL 《Physical review letters》2006,97(14):147801
We investigated the physical properties of low concentration ferroelectric nematic colloids, using calorimetry, optical methods, infrared spectroscopy, and capacitance studies. The resulting homogeneous colloids possess a significantly amplified nematic orientational coupling. We find that the nematic orientation coupling increases by approximately 10% for particle concentrations of 0.2%. A manifestation of the increased orientational order is that the clearing temperature of a nematic colloid increases by up to 40 degrees C compared to the pure liquid crystal host. A theoretical model is proposed in which the ferroelectric particles induce local dipoles whose effective interaction is proportional to the square of the orientational order parameter. 相似文献
30.
We discuss the sensitivity of a population of coupled oscillators to differences in their natural frequencies, i.e., to detuning. We argue that for three or more oscillators, one can get great sensitivity even if the coupling is strong. For N globally coupled phase oscillators we find there can be bifurcation to extreme sensitivity, where frequency locking can be destroyed by arbitrarily small detuning. This extreme sensitivity is absent for N = 2, appears at isolated parameter values for N = 3 and N = 4, and can appear robustly for open sets of parameter values for N > or = 5 oscillators. 相似文献