Synthesis and structure of fullerene halides in the C60-(TiCl4 + Br2) system: Molecular structures of (C60Cl5)2, C60 X 6, C60 X 8, and C60 X 24( X = Cl, Br)

The reactions in the C₆₀-(TiCl₄ + Br₂) system have been performed in ampoules at elevated temperatures. The molecular structure of the fullerene halides (C₆₀Cl₅)₂, C₆₀ X ₆, C₆₀ X ₈, and C₆₀ X ₂₄ (X = Cl, Br) has been determined and refined using single-crystal X-ray diffraction. It has been established that an increase in the bromine concentration results in an increase in the number of halogen atoms attached to the fullerene cage and in an increase in the relative fraction of bromine atoms in mixed halogen derivatives from almost pure chlorides (C₆₀Cl₅)₂ and C₆₀Cl₆ to halides C₆₀ X ₈ and C₆₀ X ₂₄ with a high relative bromine content. Original Russian Text ? S.I. Troyanov, A.V. Burtsev, E. Kemnitz, 2009, published in Kristallografiya, 2009, Vol. 54, No. 2, pp. 268–275.     

Crystal and molecular structures of trifluoromethyl derivatives of C82 fullerene: C82(CF3)12 and C82(CF3)18

Trifluoromethyl derivatives of C₈₂ have been obtained by the reaction between a higher fullerene mixture and trifluoromethyliodide, with subsequent isolation by high-performance liquid chromatography. The crystal and molecular structures of C₈₂(CF₃)₁₂ and C₈₂(CF₃)₁₈ have been determined by single crystal X-ray diffraction using synchrotron radiation. Both molecules are derivatives of C ₂-C₈₂ fullerene (isomer 3).     

Crystal and molecular structures of trifluoromethyl derivatives of fullerene C86, C86(CF3)16 and C86(CF3)18

Trifluoromethyl derivatives of C₈₆ were obtained by the reaction of a mixture of higher fullerenes with trifluoromethyl iodide, followed by the HPLC separation of the products. The crystal and molecular structures of C₈₆(CF₃)₁₆ (two isomers) and C₈₆(CF₃)₁₈ were determined by single-crystal X-ray diffraction using synchrotron radiation. All compounds studied are derivatives of the cage isomer of C₈₆ no. 17 (C ₂). Original Russian Text ? S.I. Troyanov, N.B. Tamm, 2009, published in Kristallografiya, 2009, Vol. 54, No. 4, pp. 637–641.     

Precise XPS depth profile of soda-lime-silica glass using C60 ion beam

Ar ion sputtering is one of the most accepted techniques for depth profiling in practical X-ray photoelectron spectroscopy (XPS) analysis, while this technique is known to be inadequate for quantitative analysis of glass including mobile ions such as soda-lime-silica glass. For the precise depth profiling on XPS depth analysis, three methods, (i) coating of conductive thin film on glass surface, (ii) sample cooling at the temperature of −130 °C and (iii) buckminsterfullerene (C₆₀) ion sputtering, were investigated to suppress the migration of mobile ions in glass. In our best knowledge, it is the first time to succeed the precise XPS depth analysis of soda-lime-silica glass (70.4SiO₂, 0.9Al₂O₃, 7.3MgO, 7.8CaO, 13.6Na₂O in mol%) without compositional change by using C₆₀ ion sputtering. The precise analysis revealed that the ion implantation during Ar ion sputtering principally resulted in the compositional change due to the migration of mobile ions.     

Low-temperature synthesis of C60 thin films by ionized cluster beam deposition technique

C₆₀ films on Si(1 1 1) have been grown at low substrate temperature of 100°C by ionized cluster beam deposition technique. Fourier transform infrared (FTIR) transmission spectroscopy, Raman measurements and X-ray diffraction are employed to investigate the structure of deposited films. The results show that the acceleration voltage plays an important role in the growth of the films. As the acceleration voltage is moderate (100 V), a pristine C₆₀ film with face-centered-cubic (fcc) crystal structure can be grown. Further increase of the acceleration voltage leads to the formation of amorphous carbon (a-C) in the grown films. When the acceleration voltage is increased to 600 V, the deposited film has a complete amorphous carbon (a-C) structure.     

The effect of solvent ratio and water on the growth of C60 nanowhiskers

The growth of C₆₀ nanowhiskers (C₆₀NWs) prepared by a modified liquid–liquid interfacial precipitation method is investigated, focusing on the effect of solvent ratio and water content in the C₆₀–toluene–isopropyl alcohol (IPA) solution system. The precipitation of C₆₀NWs was markedly influenced by the solvent ratio of toluene to IPA, and the C₆₀NWs were found to grow longer above a critical diameter (D_c), which depends on the solvent ratio. The addition of a small amount of H₂O to the C₆₀–toluene–IPA solution promoted the growth of C₆₀NWs. This catalytic effect of water on the growth of C₆₀NWs was confirmed also by the experiment using heavy water (D₂O) and by the decrease of growth activation energy of C₆₀NWs with increase of H₂O content in the C₆₀–toluene–IPA solution.     

Novel carbon materials obtained by reactions of C60 fullerene with phosphorus at high temperature

C₆₀ fullerene reacted with phosphorus at high temperatures to graphitic materials with strongly differing properties. Several spectroscopic investigations as Raman, ESR, XPS and ³¹P-NMR as well as TEM and ESEM have shown that the structural order of the mostly micro-crystalline materials increased with increasing reaction temperatures and decreasing phosphorus content. At suitable preparation conditions carbon nanotubes are formed, which are disordered in most cases, but partly exhibit high structural order (single-wall nanotubes), too. The prepared materials are very hard, e.g. harder than silica, intensely coloured and electrically conductive. Their hardness decreased with rising phosphorus content, and their conductivity increased with decreasing phosphorus content.     

Synthesis, Crystal Structure and Properties of the Binuclear Complex [Sm2(C10H9N2O4)2(C10H8N2O4)2(H2O)4]

Abstract  A novel binuclear Smarium (III) complex with N-(2-propionic acid)-salicyloyl hydrazone (C₁₀H₁₀N₂O₄, H₃L) was prepared and characterized. The crystal structure of [Sm₂(H₂L)₂(HL)₂(H₂O)₄] (1) was determined by X-ray single crystal diffractometry. 1 crystallizes in the monoclinic systerm, space group P2(1)/c, with a = 0.10229(2), c = 31.549(7), b = 0.70599(15) nm, and Z = 4. In the structure, Sm(III) is nine-coordinated by carboxyl O and acyl O atoms and imido N atoms of two ligands (H₂L and HL forms) and O atoms from two water molecules. H₂L and HL act as tridentate ligands which form two stable five-numbered chelating rings sharing one edge in the keto form for each ligand, and the carboxyl groups of two ligands were coordinated via bidentated bridging form. The coordination polyhedron around Sm (III) was described as a monocapped square antiprism. The inter- and intramolecular hydrogen bonds resulted in a three-dimensional network and provided extra stability for the structure. The complex was researched the interaction with calf thymus DNA by electronic absorption titration and emission titration. The results show that the complex is bound to calf thymus DNA mainly by intercalation .The complex also shows good fluorescence property. Index Abstract  The title compound, [Sm₂(H₂L)₂(HL)₂(H₂O)₄] was synthesized by the treatment of N-(2-propionic acid)-salicyloyl hydrazone (C₁₀H₁₀N₂O₄, H₃L) and Sm(NO₃) · 4H₂O and its crystal structure determined. Single crystal X-ray diffraction analysis reveals that Sm (III) is nine-coordinated by carboxyl O and acyl O atoms and imido N atoms of two ligands (H₂L and HL forms) and O atoms from two water molecules. The carboxyl groups of two ligands were coordinated via bidentated bridging form. The coordination polyhedron around Sm (III) was described as a monocapped square antiprism. The inter- and intramolecular hydrogen bonds resulted in a three-dimensional network and provided extra stability for the structure.      

Crystal and Molecular Structures of C6H5CH2SOCH2CONHCH2C6H5 and C6H5SOCH2CON(iC3H7)2

Abstract  The crystal structures for two of the ligands C₆H₅CH₂SOCH₂CONHCH₂C₆H₅ (1) and C₆H₅SOCH₂CON(ⁱC₃H₇)₂ (2) have been determined by X-ray diffraction. These compounds crystallize in orthorhombic system with space groups and cell parameters, Pca21(no. 29), a = 8.4600(5) ?, b = 5.3534(5) ?, c = 32.136(2) ?, V = 1455.42(15) ?³ and Pna21(no. 33) a = 17.5563(11) ?, b = 5.7902(4) ?, c = 14.2866(9) ?, V = 1452.30(16) ?³, respectively. These molecules are stabilized in solid state by various intra and intermolecular hydrogen bonding interactions to give polymeric structures. The reported IR spectra of these compounds in solid state could be explained on the basis of the observed intermolecular hydrogen bonding interactions. Index Abstract  The title compounds C₆H₅CH₂SOCH₂CONHCH₂C₆H₅ (1) and C₆H₅SOCH₂CON(ⁱC₃H₇)₂ (2) were prepared by the oxidation of corresponding sulfides with H₂O₂/SeO₂ in methanol and their structures were determined. The structures show that the SO and CO groups are having “anti” configuration in 1 and “syn” configuration in 2. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Synthesis and X-ray structural investigation of K2(H5O2)[UO2(C2O4)2(HSeO3)]

The synthesis and X-ray diffraction analysis of K₂(H₅O₂)[UO₂(C₂O₄)₂(HSeO₃)] single crystals have been performed. This compound crystallizes in the triclinic system with the unit-cell parameters a = 6.7665(4) ?, b = 8.8850(4) ?, c = 12.3147(7) ?, α = 94.73°, β = 90.16°, γ = 92.11°, sp. gr. P[`1]P\bar 1, Z = 2, and R = 0.019. The basic structural units are island [UO₂(C₂O₄)₂(HSeO₃)]³⁻ groups, which belong to the AB ₂⁰¹ M ¹ crystallochemical group of uranyl complexes (A = UO₂²⁺, B ⁰¹ = C₂O₄²⁻, and M ₁ = HSeO₃⁻). Uraniumcontaining complexes are linked through K⁺ and H₅O₂⁺ ions and via a system of hydrogen bonds with the participation of oxonium hydrogen atoms in this structure.     

Synthesis and crystal structures of two copper(I) π-complexes with 1-allyloxybenzotriazole of CuBr?C6H4N3(OC3H5) and 2CuCl?C6H4N3(OC3H5) compositions

Both compounds of CuBr⋅C₆H₄N₃(OC₃H₅) (sp. gr. P1, a = 7.633(1) Å, b = 9.987(1) Å, c = 14.898(2) Å, α = 104.75(1)^∘, β = 94.76(1)^∘, γ = 106.90(1)^∘) (I) and 2CuCl⋅C₆H₄N₃(OC₃H₅) (sp. gr. Cc, a = 11.2483(4) Å, b = 16.7076(6) Å, c = 7.2948(3) Å, β = 118.612(2)^∘) (II) composition were prepared by alternating-current electrochemical synthesis. In I due to a bridging function of organic moieties 16-membered cycles appear which are combined into ribbons {Cu₂Br₂[(C₆H₄N₃(OC₃H₅)]₂}_n. Each of two crystallographically independent copper atom possesses a trigonal-pyramidal arrangement with different degree of tetrahedral distortion. Distinctive numbers of hydrogen bonds around Br1 and Br2 atoms cause rather appreciable distinctions in copper–olefinic bond interaction effectiveness for each metal atom. In II Cu₂Cl₂ rhombs are joined to infinite chains oriented along [010] direction. Each ligand molecule is also coordinated through the C=C—bond of the allylic group to copper atom of one inorganic chain and through the nitrogen atom to a metal atom belonging to another copper-halide chain. Cu1 atoms is tetrahedrally surrounded by three chlorine atoms and nitrogen one, whereas a trigonal-planar arrangement of Cu2 atom is formed by two halogen atoms and slightly disordered olefinic group.     

Crystallization kinetics of amorphous Se60S20Te20

The temperature and the time dependence of the electrical conductivity (6) of a-Se₆₀S₂₀Te₂₀ are investigated. Conductivity anomalies are observed during the crystallization growth from both the amorphous solid and supercooled liquid phases. The changes of 6 during different isothermal annealing of a-Se₆₀S₂₀Te₂₀ samples with time are used to determine the ratio transformed from amorphous to crystalline. A value of 0.97±0.16 eV has been obtained for the activation energy of the crystal growth in the temperature range of 120–170°C.     

Partial correlations in Ni60Nb40 metallic glass

Combined X-ray and neutron diffraction experiments were performed on the Ni₆₀Nb₄₀ metallic glass samples prepared by rapid quenching from the melt with natural Ni^nat and isotope ⁵⁸Ni, respectively. The partial structure factors were separated for the three kinds of atomic pairs: NiNi, NiNb and NbNb. The partial distribution functions were calculated by means of Fourier transformation and the following atomic distances were obtained: $\text{r}{}_{\mathrm{<mtext>NiNi</mtext>}}\text{=2.52}\text{A}\text{?}\text{, r}{}_{\mathrm{<mtext>NiNb</mtext>}}\text{=2.72}\text{A}\text{?}$ and $\text{r}{}_{\mathrm{<mtext>NbNb</mtext>}}\text{=2.70}\text{A}\text{?}$. The values n_NiNi=7.3, n_NiNb=4.5, n_NbNi=6.8 and n_NbNb=5.4 were obtained for the number of nearest neighbours.     

Magnesium-doped InGaAs using (C2H5C5H4)2Mg: application to InP-based HBTs

Heavily magnesium-doped p-type-InGaAs layers on InP(100) substrates were successfully grown, for the first time, by low-pressure metalorganic chemical vapor deposition (MOCVD) using bis-ethylcyclopentadienyl-magnesium, (C₂H₅C₅H₄)₂Mg (EtCp₂Mg), as organometallic precursor for the Mg. It was experimentally verified that the room-temperature hole concentration of Mg into InGaAs increased with increase of the V/III ratio and decrease of the growth temperature. A maximum hole concentration of over 4 × 10¹⁹ cm⁻³ was obtained. The diffusion coefficient of Mg in InGaAs was experimentally derived to be 10⁻¹² cm²/s at 800°C, which was comparable to that of Be. Finally, InP/InGaAs heterojunction bipolar transistors (HBTs) with Mg-doped bases were fabricated successfully. Measured maximum current gain was about 320 with a 90 nm thick base and a sheet resistance of the base layer of 1.28 kΩ/sq.     

Structure of diaqua(itaconato) cadmium(II), [Cd(C5H4O4)(OH2)2]

[Cd(C₅H₄O₄)(OH₂)₂] (1), crystallizes in the monoclinic system, space groupP2₁/n, with lattice parametersa=7.323(2),b=16.028(6),c=7.202(2) Å, β=113.11(1)°, andZ=4. The Cd atom coordinates to seven oxygens in a monocapped trigonal antiprism fashion. The antiprisms share one vertex to form chains which run approximately parallel to thec axis. The itaconate ligands link the chains to form layers which stack along theb axis.     

Disorder in LixFePO4: From glasses to nanocrystallites

Li_xFePO₄ glasses have been prepared by fast-quenching method in the whole range of composition 0 ? x ? 1. The amorphous state of glassy materials is confirmed by X-ray diffraction. Information concerning the local environment of Li and Fe cations and the configuration of (PO₄)³⁻ oxo-anions is obtained by Fourier transform infrared (FTIR) spectroscopy. While the LiFePO₄ crystalline materials undergo a transition from the paramagnetic to the antiferromagnetic ordering at 52 K, no magnetic ordering is observed in the vitreous samples that realize random field systems, so that a spin glass-like freezing is observed at low temperature. The paramagnetic Curie temperature of Li_xFePO₄ is independent of x and shifted to θ = −60 K in the glassy state, due to a significant distortion of the FeO₆ octahedra that alters the superexchange path inside the atomic FeO₄ layers of the crystallized structure. On another hand, the PO₄ tetrahedra are not significantly distorted in the glassy phase. The results are compared with highly disordered, but nanocrystallized LiFePO₄ recently obtained at the early stage of synthesis by solid state reaction at 300 °C. In this latter case, the lack of long-range antiferromagnetic ordering is due to substitutional disorder among the cationic sublattice.     

Isochronal crystallization kinetics of Cu60Zr20Ti20 bulk metallic glass

Isochronal crystallization kinetics of Cu₆₀Zr₂₀Ti₂₀ bulk metallic glass has been investigated by differential scanning calorimetry. By means of the Kissinger, Ozawa, Kempen, Matusita and Gao methods, average effective activation energies for the first and second crystallization reactions in Cu₆₀Zr₂₀Ti₂₀ are calculated to be about 375 ± 9 and 312 ± 11 kJ mol⁻¹, respectively, which are smaller than the values deduced from isothermal experiments. Meanwhile, average Avrami exponents, 3.0 ± 0.1 and 3.4 ± 0.2, for two crystallization reactions in isochronal anneals, differ from the value about 2.0 in isothermal anneals. The nonidentity of the Avrami exponents and effective activation energies may be contributed to different crystallization mechanisms and the nature of non-isokinetic between isochronal and isothermal experiments. The values of frequency factor k₀ for the first and second crystallization reactions of Cu₆₀Zr₂₀Ti₂₀ are (1.7 ± 0.3) × 10²⁴ and (7.0 ± 0.8) × 10¹⁸ s⁻¹, respectively, and the large value of k₀ has been discussed in terms of the atomic configuration and interaction.     

Structural, microstructural and electronic characteristics of quasicrystalline and carbon containing fullerene (C60) and graphitic tubule, solids

The quasicrystalline and recently discovered carbon bearing exotic solids- the fullerenes (e.g. C₆₀) and their tubule relatives Nano-tubules have a common linkage in the sense that they have built in icosahedral symmetry either at the level of lattice — as in QC materials, or motif e.g. in fullerene or tubule (caps). It is, therefore, of interest to explore the structural features and properties (e.g. electronic behaviour) of the solids on a comparative basis. The basic theme of this paper centres around this aspect. We have discussed and described the structural/microstructural characteristics and properties (with emphasis on electronic behaviour) of the QC, C₆₀ and Nano-tubule. Attempts have then been made to bring out their comparisons for these type of icosahedron bearing solids.

The case of comparison of structural behaviours and grass root electronic characteristic e.g. Brillouin zones and density of states of the QC and C₆₀ solid — the special carbon bearing material — have been taken first. Thereafter, the case of tubule-solids which are related to C₆₀ have been taken up. Then inter-relationship between tubule and C₆₀ and the exotic electronic characteristics of the tubules have been discussed and described. Finally the similarities and dissimilarities of the three types of solids in regard to their structural and electronic behaviours have been outlined.