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991.
The Crystal Structure of KPdMIVF7 (MIV = Zr, Hf) Blue single crystals of KPdZrF7 are obtained by heating the binary fluorides in sealed Pt-tubes under dry argon (solid state reaction, T ≈? 720°C, t ≈? 14 d). The compound crystallizes orthorhombically in the space group Pnna-D (Nr. 52); lattice parameters are a = 1 132.3(5) pm, b = 797.5(2) pm, c = 639.8(1) pm; Z = 4 (Four cycle diffractometer data, AED2). According to [F4PdF2/1ZrF5] distortet [PdF6]-octaedra are connected with pentagonal-bipyramidal [ZrF7]-polyhedra via two bridging F?, resulting in [PdZrF11]-groups. These [PdZrF11]-groups built up a threedimensional-network with K+ in its spacings. KPdHfF7 crystallizes isotypically (a = 1 136.1(3) pm, b = 796.4(2) pm und c = 638.8(1) pm; four cycle diffractometer data, AED2). 相似文献
992.
芫花 (DaphnegenkwaSieb.etZucc.)属于瑞香科植物[1] ,芫花的浸取液对棉蛉虫、稻螟虫、菜青虫、班蝥等害虫具有较好的杀虫效果 ,且对人畜无害 ,是一种理想的无公害农药[2 ] 。为了提高药效 ,更好地开发这种无公害农药 ,本文对芫花中杀虫有效成分的提取工艺与杀虫效果进行了初步研究。1 实验部分1 1 试剂和仪器苯 ,氯仿和 95 %的乙醇均为分析纯 ;岛津UV -2 40型紫外可见分光光度仪 ;FT -80ANMR仪。1 2 实验方法芫花枝条干粉 1 5 0 0g,加水 1 0 .0 0L煮沸 1 2小时 ,煮沸过程中陆续补加少量水分。将煮沸… 相似文献
993.
Bis(benzoylpyridin-toluensulfonylhydrazido)nickel Ni(BPSH)2 · H2O — Relations between Structure, Redox, and Extraction Properties of Heterocyclic Sulfonamido Chelates The crystal structure of Ni(BPSH)2 · H2O was determined by x-ray diffraction: monoclinic, space group P21/c (Nr. 14); a = 15.077(4) Å, b = 14.901(3) Å, c = 16.335(3) Å, β = 95.74(1)°. R = 0.047 for a total of 5564 observed reflexions. Ni(BPSH)2 · H2O has a distorted tetrahedral structure with two six-membered chelate rings, one of them with a boat from. The electron system of the building blocks CNN? within the chelate rings approaches that of a diazallyl group. The result is a high electron density on the sp2-hybridized donor atom N? and, as a consequence, a short Ni? N?-distance (1.908 or 1.924 Å). The electronic properties of N? also explain the high NH-acidity of the acid H(BPSH) (pks = 9,51 in 75 per cent dioxane) and the ligand field strength of BPSH? which is low compared to that of other bidentate sulfonamido ligands and which is reflected in the paramagnetism of Ni(BPSH)2 · H2O. The redox behavior of metal chelates of the type, which is represented by Ni(BPSH)2 · H2O, is caused by a building block of the ligand which is also present in bipyridyl or in the 1,4-diaza-1,3-dienes. The central atoms M11 have only the function of interference factors. 相似文献
994.
The ion clusters H+X· (H2)n (X = N2, CO, O2 and H2 andn = 0, 1, 2) are investigated by means of SCF and CI computations in a double-zeta plus polarization gaussian basis It is found that hydrogen molecules attack the proton of H+X perpendicularly. The calculated stabilization energies are in agreement with experimental values of δH0. 相似文献
995.
N. Blidi Boukamel A. Krallafa D. Bormann L. Caron M. Canipelle S. Tilloy E. Monflier 《Journal of inclusion phenomena and macrocyclic chemistry》2002,42(3-4):269-274
Quantum mechanical calculations on the (4-tert-butylphenyl)(3-sulfonatophenyl) (phenyl) phosphine/-cyclodextrin inclusion complex werecarried out using semi-empirical calculations. Inclusion process pathways are describedand the most probable structures of the 1:1 complex are sought through a global potentialenergy scan. The calculations suggest that the most stable structure is obtained whenthe aromatic ring bearing the tert-butyl group is includedinto the hydrophobic cavity of the -cyclodextrin from theside of the primary hydroxyl groups. 相似文献
996.
M. SenŌ H. Noritomi Y. Kuroyanagi K. Iwamoto G. Ebert 《Colloid and polymer science》1984,262(11):896-901
The molecular conformations of poly(N5-dihydroxyethylaminopropyl-L-glutamine) and poly(N5-dihydroxyethyl-L-glutamine) were investigated in reversed micelles of AOT as well as in aqueous solutions. Both poly(-amino acid)s assume disordered structures in pure water. The conformation of poly(N5-dihydroxyethylaminopropyl-L-glutamine) transits into-helix in the reversed micelles as the molar ratio of water to AOT (w0=[H2O]/[AOT]) becomes smaller. A similar conformational transition was also observed in aqueous solutions when a certain amount of AOT was added. Under these conditions, however, poly(N5-dihydroxyethyl-L-glutamine) did not undergo a conformational transition into-helix. 相似文献
997.
Results of calorimetric (DSC) experiments on a series of poly (n-alkylmethcrylates), from methyl to pentyl, after different aging timest
e at different aging temperaturesT
e are presented. The aging behavior is quite different from that in other polymers, for example PS. For all poly(n-alkylmethacrylates) investigated the aging peak temperatureT
max is shifted parallel to the aging temperatureT
e in a large temperature interval below the glass temperature. The results are discussed with respect to shear and entropy response in the splitting region. 相似文献
998.
Roli Saxena L. D. Kandpal G. N. Mathur 《Journal of polymer science. Part A, Polymer chemistry》2002,40(22):3959-3966
Poly(benzobisthiazole)s containing tetrafluorophenyl and bromophenyl moieties were synthesized via the polycondensation of 2,5‐diamino‐1,4‐benzenedithiol dihydrochloride with tetrafluorophthalic acid and 4‐bromoisophthalic acid under a nitrogen atmosphere. The polymers were characterized by X‐ray diffraction, spectroscopy (infrared and solid‐state 13C NMR), and thermal analysis, including differential scanning calorimetry and thermogravimetric analysis. The thermogravimetric analysis showed that the thermal stability of the polymers was 490–515 °C under a nitrogen atmosphere. The synthesized polymers showed good solubility in organic solvents. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3959–3966, 2002 相似文献
999.
N. Nassif A. Coiffier T. Coradin C. Roux J. Livage O. Bouvet 《Journal of Sol-Gel Science and Technology》2003,26(1-3):1141-1144
Whole E. coli bacteria have been trapped within silica gels obtained via the acidification of sodium silicate and silica nanoparticles solutions. Their -galactosidase enzymatic activity increases with time, suggesting that their membrane is partially lysed during the encapsulation process. Such a lysis can be greatly reduced when encapsulation is performed in the presence of gelatin. The biocatalytic activity of trapped bacteria remains almost constant for more than a week. Moreover bacteria trapped in such gels remain able to incorporate glucose, showing that their viability has been preserved. 相似文献
1000.