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71.
72.
Arndt W. Schmidt 《Tetrahedron》2009,65(28):5484-1882
We describe a seven-step total synthesis of the triquinane sesquiterpene (±)-cameroonanol using a Lewis acid-promoted [3+2] cycloaddition of an allylsilane and a modified Fleming-Tamao oxidation as key reactions. 相似文献
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Kuit Arndt 《Colloid and polymer science》1909,4(1):1-5
Ohne Zusammenfassung 相似文献
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Volodymyr Babizhetskyy Dr. Kurt Hiebl Hansjürgen Mattausch Arndt Simon 《无机化学与普通化学杂志》2010,636(7):1229-1235
New ternary rare earth metal boride carbides with compositions close to RE10B9C10 (RE = Gd, Tb) were prepared from the elements by melting around 1800 K followed by annealing in silica tubes at 1270 K for one month. The crystal structure of the terbium compound was solved by single‐crystal X‐ray diffraction. It crystallizes in a new structure type in the monoclinic space group P21/c, a = 7.937(1), b = 23.786(2), c = 11.172(1) Å, β = 133.74(1)°, Z = 4, R1 = 0.045 (wR2 = 0.11) for 5713 reflections with Io > 2σ(Io). In the structure BC2 units and single carbon atoms are attached to a zigzag boron chain forming the unprecedented B18C18 branching unit with a B–B distance of 2.42(2) Å between these units. In addition isolated carbon atoms occupy the centres of elongated octahedra formed by rare earth metal atoms. Disorder in the terbium position together with anomalous displacement ellipsoids for carbon atoms except of those in the BC2 fragments can be rationalized in terms of a slight deviation in stoichiometry, Tb10B9+xC10–x (x ≈? 0.2). The terbium compound is ferromagnetic below TC ≈? 45 K. Due to the presence of moderately narrow domain walls the magneto‐crystalline energy is small. 相似文献
79.
Stepan Oryshchyn Volodymyr Babizhetskyy Olga Zhak Jean-Yves Pivan Arndt Simon 《Journal of solid state chemistry》2010,183(11):2534-2543
The new ternary pnictides Er12Ni30P21 and Er13Ni25As19 have been synthesized from the elements. They crystallize with hexagonal structures determined from single-crystal X-ray data for Er12Ni30P21 (space group P63/m, a=1.63900(3) nm, c=0.37573(1) nm, Z=1, RF=0.062 for 1574 F-values and 74 variable parameters), and for Er13Ni25As19 (Tm13Ni25As19-type structure, space group P6?, a=1.6208(1) nm, c=0.38847(2) nm, Z=1, RF=0.026 for 1549 F-values and 116 variable parameters). These compounds belong to a large family of hexagonal structures with a metal-metalloid ratio of 2:1. HRTEM investigations were conducted to probe for local ordering of the disordered structure at the nanoscale. The magnetic properties of the phosphide Er12Ni30P21 have been studied in the temperature of range 2<T<300 K and with applied fields up to 5 T. The magnetic susceptibility follows the Curie-Weiss law from 4 to 300 K. The measured value of μeff=9.59 μB corresponds to the theoretical value of Er3+. 相似文献
80.
Semisynthetic techniques have greatly contributed to the rapid development of Chemical Biology in recent years. In this regard the semisynthesis of complex modified proteins as well as the selective derivatization of natural products has evolved into more than mere proof‐of‐principle concepts but powerful tools to probe protein functions. This technology provides a solid basis for further investigations on proteomics and qualitative and quantitative cell biology. The interdisciplinary charter bridging chemistry and biology is the hallmark of semisynthesis. It can be expected that its scientific impact will further increase in the future. 相似文献