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51.
Harry Adams Neil A. Bailey David E. Fenton Choki Fukuhara Masatoshi Kanesato 《Supramolecular chemistry》2013,25(4):325-330
Abstract The synthesis and crystal structure of the diprotonated cryptand derived from the reaction of tren and 2,6-diacetyl pyridine is reported. The imino nitrogens of the Schiff base linkages are directed so that the dicarbimine functions are in trans, trans geometry relative to the pyridine C-N bond. This configuration has not previously been reported in related pyridine-derived Schiff base macrocycles. 相似文献
52.
Nobutaka Shibata Daisuke Nagao Haruyuki Ishii Mikio Konno 《Colloid and polymer science》2013,291(1):137-142
Janus composite particles with a combination of organic and inorganic substances were synthesized by soap-free emulsion polymerization in which an amphoteric initiator of 2,2′-azobis[N-(2-carboxyethyl)-2-2-methylpropionamidine] (VA-057) was employed to introduce a polystyrene (PSt) lobe onto silica cores surface-modified with 3-methacryloxypropyltrimethoxy silane (MPTMS). Thermogravimetric analysis and X-ray photoelectron spectroscopy were used to characterize the surface-modified silica particles and showed that a small amount of MPTMS introduced onto the surface of silica particles could successfully prepare SiO2–PSt Janus particles. The oxide part of SiO2–PSt Janus particles obtained with the polymerization was further surface-modified with 3-aminopropyltriethoxysilane (APS) to introduce positively charged amino groups on the silica surface. The silica surface modified with APS was covered with gold by electroless deposition in which a gold precursor of auric chloride was reduced with ascorbic acid in the presence of polyvinylpyrrolidone. The electroless deposition of gold successfully produced Janus particles with a combination of gold and PSt surfaces. Furthermore, dissolution of the polymer component of the Au–PSt Janus particles in tetrahydrofuran led to another Janus type of particles with an inorganic combination of Au and SiO2. 相似文献
53.
Kei Fujise Eiji Tsurumaki Gaku Fukuhara Nobuyuki Hara Yoshitane Imai Shinji Toyota 《化学:亚洲杂志》2020,15(16):2456-2461
Polycyclic aromatic hydrocarbons consisting of three fused anthracene units were designed as new π‐conjugated compounds having helical structures. These expanded helicenes were synthesized by Pt‐catalyzed cycloisomerization of the corresponding ethynyl‐substituted precursors. The nonplanar and helical structure was confirmed by X‐ray analysis and DFT calculations, and the barrier to helical inversion was estimated to be 34 kJ mol?1. The enantiomers of the diphenyl derivative were successfully resolved by chiral HPLC. Enantiopure samples showed good chiroptical performance in the CD (|Δ?| 1380 L mol?1 cm?1) and CPL (|glum| 0.013) spectra, and these values were considerably large for simple organic molecules. The unique chiroptical properties are discussed on the basis of the molecular structure and the electronic state with the aid of time‐dependent DFT calculations. 相似文献
54.
The discovery that supporting electrolytes can be effectively confined in typical organic solvents in a c-Hex-based multiphase electrolyte solution has led to the development of a novel heterogeneous continuous flow synthetic system. PTFE fiber functions as a separation filter that can efficiently isolate the c-Hex phase from multiphase electrolyte solutions. This system has demonstrated both electrochemical solvating and carbon-carbon bond forming reactions. Hydrophobic substrates can be introduced into the reactor as c-Hex solutions, which are then electrochemically transformed into the target hydrophobic products that pass through the PTFE fiber as c-Hex solutions. 相似文献
55.
Shimizu Y Shiokawa N Yamamoto N Kozuma M Kuga T Deng L Hagley EW 《Physical review letters》2002,89(23):233001
Propagation of a light pulse through a high-Q optical microcavity containing a few cold atoms (N<10) in its cavity mode is investigated experimentally. With less than ten cold rubidium atoms launched into an optical microcavity, up to 170 ns propagation lead time ("superluminal"), and 440 ns propagation delay time (subluminal) are observed. Comparison of the experimental data with numerical simulations as well as future experiments are discussed. 相似文献
56.
The proton magnetic resonance spectra of the three title carbanions have been observed in THF with potassium as a counter ion. The ortho-protons in the α-methylbenzyl carbanion are nonequivalent at room temperature. This shows that the α-carbon in this carbanion is in the near-sp2 configuration. The aromatic proton chemical shifts of the benzylpotassium obtained here are at higher shielding than those of benzyllithium reported previously by Sandel and Freedman. This seems to arise from the different ionic nature of the bonds between carbon and metal in the carbanions. 相似文献
57.
Mikio Kano 《Journal of Graph Theory》1985,9(1):129-146
Let a and b be integers such that 0 ? a ? b. Then a graph G is called an [a, b]-graph if a ? dG(x) ? b for every x ? V(G), and an [a, b]-factor of a graph is defined to be its spanning subgraph F such that a ? dF(x) ? b for every vertex x, where dG(x) and dF(x) denote the degrees of x in G and F, respectively. If the edges of a graph can be decomposed into [a.b]-factors then we say that the graph is [2a, 2a]-factorable. We prove the following two theorems: (i) a graph G is [2a, 2b)-factorable if and only if G is a [2am,2bm]-graph for some integer m, and (ii) every [8m + 2k, 10m + 2k]-graph is [1,2]-factorable. 相似文献
58.
In this paper we study the singular Fano compactifications of with small Gorenstein singularities and determine the structure of such a compactification in the case of the Fano index r 2.Mathematics Subject Classification (2000): 14J45 , 32J05 相似文献
59.
The squeezed vacuum resonant on the (87)Rb D1 line (probe light) was injected into an optically dense rubidium gas cell with a coherent light (control light). The output probe light maintained its quadrature squeezing within the transparency window caused by the electromagnetically induced transparency (EIT). The results reported here are the first realization of EIT in the full quantum regime. 相似文献
60.
Tsuboyama A Takiguchi T Okada S Osawa M Hoshino M Ueno K 《Dalton transactions (Cambridge, England : 2003)》2004,(8):1115-1116
The synthesis, structure, and photophysical properties of a new cyclometalated dinuclear iridium complex, (ppy)2Ir(mu-BPB)Ir(ppy)2 [ppy = 2-phenylpyridine, BPB = 1,4-bis(pyridin-2-yl)benzene], have been investigated. 相似文献