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221.
GM Friederichs I Schellenberg R Pöttgen V Duppel L Kienle JS Auf der Günne D Johrendt 《Inorganic chemistry》2012,51(15):8161-8167
The topochemical deintercalation of Na(+) ions from solid NaFeAs at room temperature in THF with iodine yields the superconducting phase Na(1-y)Fe(2-x)As(2) (T(c) ≈ 11 K). This metastable iron arsenide decomposes at 120 °C and is not accessible by high-temperature solid-state synthesis. X-ray powder diffraction confirms the ThCr(2)Si(2)-type structure, but reveals very small coherently scattering domains with a mean composition Na(0.9(2))Fe(1.7(1))As(2). HRTEM investigations show crystalline as well as strongly distorted areas with planar defects. The latter are probably due to sodium loss and disorder which is also detected by (23)Na solid state NMR. The (57)Fe-M?ssbauer spectrum of Na(1-y)Fe(2-x)As(2) shows one type of iron atoms in tetrahedral coordination. All results point to one crystallographic phase with very small domains due to fluctuations of the chemical composition. From electronic reasons we suggest the superconducting phase is presumably NaFe(2)As(2) in the ordered fractions of the sample. 相似文献
222.
Wojczykowski K Meissner D Jutzi P Ennen I Hütten A Fricke M Volkmer D 《Chemical communications (Cambridge, England)》2006,(35):3693-3695
Novel amphiphilic trithiolates possess excellent properties for gold nanoparticle (AuNP) stabilization and functionalization and cannot be replaced by exchange reactions. 相似文献
223.
Inga Cikotiene Rita Buksnaitiene Simonas Rudys Marius Morkunas Dainius Motiejaitis 《Tetrahedron》2010,66(1):251-345
An efficient and versatile tandem processes of acetalisation and cycloisomerization reactions have been developed for the reactions of 6-phenylethynylpyrimidine-5-carbaldehydes. The influence of the catalyst and role of the substituent in the position 4 of the pyrimidine ring have been studied. Regioselective synthesis of 5,7-dihydrofuro[3,4-d]pyrimidine and pyrano[4,3-d]pyrimidine cores is described. 相似文献
224.
Joaquim Li Inga Huth Lise‐Marie Chamoreau Dr. Bernold Hasenknopf Dr. Emmanuel Lacôte Dr. Serge Thorimbert Dr. Max Malacria Prof. 《Angewandte Chemie (International ed. in English)》2009,48(11):2035-2038
POM alert : The incorporation of an amide oxygen atom into the framework of the Dawson‐type polyoxometalate (POM) cluster [P2V3W15O62]9? (see picture) allows the communication of electronic effects between the organic and the inorganic parts of the molecule, including fine‐tuning of the redox properties of the entire hybrid POM by the organic components, and transmission of the POM's electron‐attracting properties to the organic moiety.
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Inga M. Aladzheva Dmitrii I. Lobanov Ol'ga V. Bykhovskaya Pavel V. Petrovskii Konstantin A. Lyssenko Tatyana A. Mastryukova 《Heteroatom Chemistry》2003,14(7):596-602
A novel facile one‐pot synthesis of the 1,2‐azaphospholanes by intramolecular alkylation of 3‐halopropyl amides of tricoordinate phosphorus has been suggested. Using this method, a series of the differently N‐substituted 1,2‐azaphospholanium salts were synthesized. 3‐Aminopropylphosphine oxides were obtained by hydrolysis of the salts. A probable mechanism of the 1,2‐azaphospholanium salts formation is discussed. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:596–602, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10209 相似文献
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Stanislav I. Klenin Inga A. Baranovskaya Vladimir O. Aseyev 《Macromolecular Symposia》1996,106(1):205-217
High molecular weight polyelectrolyte: poly(dimethylaminoethyl methacrylate) [PDMAEMA] with molecular weights MW = 28.0×106, 20.0×106, 15.0×106 was investigated in dilute solution by light scattering, flow birefringence and viscometry (at different rate gradients) in a water-acetone system by varying the weight fraction of acetone r in the mixture. At r=0.76 the polymer undergoes a reversible coil-globule transition accompanied by a drastic decrease in intrinsic viscosity [n], mean-square radius of gyration R2z1/2 and second virial coefficient A2, with no change in molecular weight. The coil asymmetry parameter p (p=2.5 at r=0.50) decreases with increasing r and attains unity (completely symmetrical particle) at the transition point (r=0.76). The anomalous behavior of the viscosity of PDMAEMA-water-acetone solutions, detected near the transition point (r=0.6+0.7), is interpreted by formation of local knots of compactization on the molecular chain under the influence of a hydrodynamic field. 相似文献