Nina V. Kozhemyakina

Max Planck Institute for Solid State Research, Stuttgart, Baden-Württemberg, Germany

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Publications (8)26.31 Total impact

  • Source
    Fullerenes Nanotubes and Carbon Nanostructures 01/2013; · 0.76 Impact Factor
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    ABSTRACT: A new fulleride, (K[DB18C6])(4)(C(60))(5)·12THF, was prepared in solution using the "break-and-seal" approach by reacting potassium, fullerene, and dibenzo[18]crown-6 in tetrahydrofuran. Single crystals were grown from solution by the modified "temperature difference method". X-ray analysis was performed revealing a reversible phase transition occurring on cooling. Three different crystal structures of the title compound at different temperatures of data acquisition are addressed in detail: the "high-temperature phase" at 225 K (C2, Z=2, a=49.055(1), b=15.075(3), c=18.312(4) Å, β=97.89(3)°), the "transitional phase" at 175 K (C2 m, Z=2, a=48.436(5), b=15.128(1), c=18.280(2) Å, β=97.90(1)°), and the "low-temperature phase" at 125 K (Cc, Z=4, a=56.239(1), b=15.112(3), c=36.425(7) Å, β=121.99(1)°). On cooling, partial radical recombination of C(60)(·-) into the (C(60))(2)(2-) dimeric dianion occurs; this is first time that the fully ordered dimer has been observed. Further cooling leads to formation of a superstructure with doubled cell volume in a different space group. Below 125 K, C(60) exists in the structure in three different bonding states: in the form of C(60)(·-) radical ions, (C(60))(2)(2-) dianions, and neutral C(60), this being without precedent in the fullerene chemistry, as well. Experimental observations of one conformation exclusively of the fullerene dimer in the crystal structure are further explained on the basis of DFT calculations considering charge distribution patterns. Temperature-dependent measurements of magnetic susceptibility at different magnetic fields confirm the phase transition occurring at about 220 K as observed crystallographically, and enable for unambiguous charge assignment to the different C(60) species in the title fulleride.
    Chemistry 02/2011; 17(6):1798-805. · 5.93 Impact Factor
  • Advanced Materials 10/2010; 22(48):5483-7. · 14.83 Impact Factor
  • Nina V. Kozhemyakina, Jürgen Nuss, Martin Jansen
    Berichte der deutschen chemischen Gesellschaft 08/2009; 2009(26):3900 - 3903. · 2.94 Impact Factor
  • Nina V. Kozhemyakina, Jürgen Nuss, Martin Jansen Prof. Dr
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    ABSTRACT: The “break-and-seal” method known to be used for synthesis of sensitive compounds (alkalides, electrides and for living anionic polymerization) was applied for the first time for fulleride synthesis providing highest purity of the reaction conditions. A new fulleride KC60(THF)5·2THF was prepared in solution by reacting fullerene C60 with potassium and dibenzo-24-crown-8 in tetrahydrofurane. Single crystals were grown from solution by the modified “temperature difference method”, single- crystal X-ray analysis was performed revealing the structure [P21212, Z = 4, a = 17.802(5), b = 30.085(9), c = 9.863(3) Å, R1 = 0.069, wR(all) = 0.191, 5563 independent reflections]. In this compound, the charge of fulleride is –1, the C60– radical-anion being fully ordered. A constitutive structural feature is octahedrally coordinated potassium atoms with five THF and one fullerideas ligands. C60– is functioning as a η3-ligand: [K(η3-C60)(η1-THF)5]·2THF.
    Zeitschrift für anorganische und allgemeine Chemie 07/2009; 635(9‐10):1355 - 1361. · 1.16 Impact Factor
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    ABSTRACT: Solutions of fullerenes in nitrogen-containing solvents constitute a specific class characterized by the formation of fullerene clusters. In the given work, we report the effect of cluster rearrangement in the system C60/N-methylpyrrolidone (NMP) after addition of water (miscible with NMP) as observed by small-angle neutron scattering (SANS). The effect has a critical character and takes place if the water relative content is higher than 40%. Despite a small scattering signal, estimates of the mean scattering length density of the clusters by SANS contrast variation can be done.
    Physica B: Condensed Matter. 11/2006; 385-386:795-797.
  • I. V. Pentin, A. A. Grosheva, N. V. Kozhemyakina
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    ABSTRACT: Miscibility gap locations in the CdTe–ZnTe and HgTe–ZnTe systems are calculated yielding the critical parameters (Tc/K, xc (second compound)) (407, 0.38) and (558, 0.33), respectively. The obtained functions allow us to predict the location of the miscibility gap in the CdTe–HgTe–ZnTe system based on the Kohler and Redlich–Kister–Muggianu procedures. Ternary phase diagrams for the Hg–Cd–Te, Cd–Zn–Te and Hg–Zn–Te systems in the subsolidus region are also estimated based on known thermodynamic properties of the binary systems and our results for the quasi-binary alloys in the paper.
    Calphad-computer Coupling of Phase Diagrams and Thermochemistry - CALPHAD-COMPUT COUP PHASE DIA. 01/2006; 30(2):191-195.
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    ABSTRACT: A study is made on a strain of higher basydiomycete Flammulia velutipes (Fr.) P. Karst. The conditions of maximum biomass production by Flammulia velutipes were studied. Soluble and insoluble fractions were isolated from mycelium. The composition of cultured mycelium and aqueous extracts from mycelium were investigated. These objects mainly contained carbohydrates (65.3 and 84.0% in insoluble and soluble fractions, respectively, and 56% mycelium), proteins (7.5–10.0% in fractions and 17.5% in mycelium), as well as an insignificant amount of mineral substances. The main carbohydrate component of fractions was glucose (53.6–78.8%); galactose and mannose were also present, as well as fucose and xylose in insignificant amounts. The aqueous extracts from mycelium demonstrated immunomodulating activity. They rendered a stimulating effect on the functional activity of macrophages—central cells of the reticluoendothelial system. The soluble fraction had a more pronounced effect than the insoluble fraction.
    Applied Biochemistry and Microbiology 46(5):536-539. · 0.69 Impact Factor