Benzene formation during aquasonolysis of selected cyclic C6Hx hydrocarbons

Yield and selectivity of benzene produced from aquasonolysis of the selected cyclic C6Hx hydrocarbons, i.e., 1,4-cyclohexadiene, 1,3-cyclohexadiene, cyclohexene, cyclohexane, and methylcyclopentane, have been investigated in this work. Benzene cannot be detected during the aquasonolysis of cyclohexane and methylcyclopentane. The order of yield and selectivity of benzene was as follows: 1,4-cyclohexadiene>1,3-cyclohexadiene>cyclohexene. The initial concentrations of substrates can affect the yield of benzene. During the aquasonolysis of 1,3-cyclohexadiene and cyclohexene, other C6 species except benzene were also found. It was suggested that benzene could directly be generated by formal dehydrogenation of cyclic C6Hx hydrocarbons.     

Sonochemical reaction of selected cyclic C6Hx hydrocarbons in organic solvents

The rates and products of the sonochemical reactions of benzene, 1,4-cyclohexadiene, 1,3-cyclohexadiene, cyclohexene, and cyclohexane in selected organic solvents have been investigated. The sonochemical reactions of these educts in the investigated organic solvents follow first-order kinetics. Generally, they are sonicated more rapidly in polar than in non-polar solvent; higher volatility of the solute results in faster sonolysis in the organic solvents. However, the sonication of cyclohexane in n-decane and the sonication of benzene in n-propanol are exceptional cases. Since cyclohexane exhibits a much higher lipophilicity and benzene a much higher hydrophilicity than other educts, it might be more difficult to transfer either educt from the bulk liquid into the cavitation bubbles. In tetrachloroethylene, the reactivity of the tested educts with in situ generated chlorine as well as chlorine-containing radical intermediates can accelerate the rate of sonochemical reactions under the employed conditions. In n-propanol and n-decane, the pyrolysis during the collapse of the cavitation bubbles is the only reaction pathway of sonolysis. In tetrachloroethylene, the pyrolysis during the collapse of the cavitation bubbles and the free radical reaction in the bulk liquid may occur simultaneously. Except for the products generated from sonolysis, products formed from chlorine transformations (substitution or addition reactions) are detected. Benzene is hardly decomposed in tetrachloroethylene. However, when FeCl3 is added into the reaction system, benzene is sonoconverted rapidly, and the product chlorobenzene was detected. In organic solvents, the sonoreaction rates and the sonoproducts are dependent on the physicochemical properties of the solvents used, as well as the volatility, the polarity and the reactivity of educts.     

配合物La（C5O3H3）3·C12H8N2·H2O的合成和表征

本以α－呋喃甲酸（Ｃ５Ｏ３Ｈ４）和邻菲罗啉（Ｃ１２Ｈ８Ｎ２）为配体,在乙醇８溶剂中与硝酸镧反应,合成了与稀土离子Ｌａ（Ⅲ）的三元混配配合物。经元素分析确定其配合物的组成为Ｌａ（Ｃ５Ｏ３Ｈ３）·Ｃ１２Ｈ８Ｎ２·Ｈ２Ｏ,同时还通过了ＩＲ、＾１ＨＮＭＲ、ＵＶ、ＴＧ－ＤＴＡ等谱光的测试与分析,表征了配合物的组成结构和性质。ＩＲ、＾１ＨＮＭＲ和ＵＶ谱的分析结果表明配体羧酸是以脱质子的酸根形式与中心稀土离子     

Adatom-vacancy mechanisms for the C6)/Al111-(6 x 6) reconstruction

The irreversible (6x6) reconstruction of the C(60)/Al(111) system from the (2sqrt[3]x2sqrt[3])R30 degrees phase is studied by first-principles techniques. We find that C60 binds optimally to the surface if an Al vacancy is created directly underneath. The removed Al atoms form a (6x6) array of ad-dimers in the interstices below the C60 overlayer, to which they strongly bind. This spontaneous local process, rather than the compression state of the unreconstructed C60 overlayer, explains why one molecule out of three protrudes from the surface upon reconstruction.     

Electronic structure and spectra of [Cr(C6H6)2]+ and [Fe(C5H5)2]+

The high-resolution N.M.R. spectra of a series of bicyclo [2.2.1] heptanols are discussed. Three unusual features are observed: (a) relatively large ⁴ J's; (b) unequal J _endo-endo's and J _exo-exo's; and (c) unusual magnetic shieldings.

These are presented as empirical phenomena and only little attempt is made to discuss their implications.     

星状C60(CH3)x(PAN)x共聚物的光致发光研究

利用物理喷束淀积（ＰＪＤ）技术制备Ｃ６０（ＣＨ３）ｘ（ＰＡＮ）ｘ共聚物的薄膜。这种共聚物中,Ｃ６０分子位于星状结构的中心,聚丙烯腈（ＰＡＮ）主链修饰在Ｃ６０分子的周围。吸收及荧光光谱表明：Ｃ６０分子与聚丙烯腈（ＰＡＮ）有明显的相互作用,而且这种相互作用与ＰＡＮ的链长有关。Ｃ６０分子与ＰＡＮ间存在一定的激发传递过程,从而导致ＰＡＮ荧光的部分猝灭。     

Computational reconstitution of crystal structures and (p,T) phase diagrams of benzene C6H6 and hexachlorobenzene C6Cl6

Abstract

With a simplified dynamical model for molecular packing analysis, crystal and molecular structures of benzene C₆H₆ and hexachlorobenzene C₆H₆ were investigated. This model includes thermal motion and molecular deformation effects. Several crystalline structures have been found by the calculation. They are compared to experimental structures determined at various temperatures and pressures, by X-ray diffraction or neutron scattering. A schematic (p, T) phase diagram is suggested for each compound.     

Study of C60/Au(110)-p(6x5) reconstruction from In-plane X-Ray diffraction data

Fullerene molecules absorbed on the highly anisotropic Au(110)-p(1x2) surface induce an ordered p(6x5) superstructure that has been solved by applying the 2D "direct methods" difference sum function to the surface x-ray diffraction data set. We found that the C (60)-gold interface is structurally much more complex than the one previously suggested by scanning tunneling microscopy data [J. K. Gimzewski, S. Modesti, and R. R. Schlittler, Phys. Rev. Lett. 72, 1036 (1994)]. Indeed a large fraction of Au surface atoms are displaced from their original positions producing microscopic pits that may accommodate the fullerene molecules.     

2H NMR of Deuterofullerites C60D x

Deuterofullerites C₆₀D _x have been studied by means of ²H NMR spectroscopy. It has been established that there are two types of carbon–deuterium bindings in the samples under study: tip C–D with quadrupole constant coupling (QCC) 171 kHz and bridge –C...D...C– with QCC 56 kHz. It is possible that the latter bond is a result of the rigidity of the lattice, which is unusual for fullerene compounds.     

AC conductivity analysis and dielectric relaxation behavior of (C6H20N3)BiBr6.H2O

The N‐(3‐ammoniumpropyl)‐1,3 diammoniumpropane hexabromobismuthate (III) monohydrate exhibits a structural phase transition at T = 330 °K, which has been characterized by differential scanning calorimetric. The alternating current electrical conductivity and the dielectric relaxation properties of the (C₆H₂₀N₃)BiBr₆.H₂O compound have been investigated by means of impedance spectroscopy measurements over a wide range of frequencies and temperatures, 100 Hz–1 MHz and 290–355 °K, respectively. The Z′ and Z″ versus frequency plots are well fitted to an equivalent circuit consisting of series of combination of grains and grain boundary elements. The frequency dependent alternating current conductivity is well described by Jonscher's universal power law: σ(ω,T) = σ_DC(T) + A(T)ω^s(T). The nature of direct current conductivity variation suggests the Arrhenius type of electrical conductivity. Furthermore, the modulus plots can be characterized by full width at half height or in terms of a non‐experiential decay function φ(t) = exp(?t/τ)^β. The variation of the value of these elements with temperatures confirmed the result detected by differential scanning calorimetry measurements. Thus, the near values of activation energies obtained from the impedance and modulus spectra confirm that the transport is through an ion hopping mechanism. Copyright © 2015 John Wiley & Sons, Ltd.     

C_2H_x(x=4～6)在Ni(111)表面吸附的DFT研究

采用密度泛函理论与周期平板模型相结合的方法,对物种C_2H_x(x=4～6)在Ni(111)表面的top,fcc,hcp和bridge位的吸附模型进行了结构优化、能量计算,得到了各物种较有利的吸附位;并对最佳吸附位进行密立根电荷和总态密度分析.结果表明:C_2H_6和C_2H_4在Ni(111)表面的最稳定吸附位都是top位,吸附能分别是-36.41和-48.62 kJ·mol~(-1),物种与金属表面吸附较弱;而C_2H_5在Ni(111)表面的最稳定吸附位hcp的吸附能是-100.21 kJ·mol~(-1),物种与金属表面较强;三物种与金属表面之间都有电荷转移,属于化学吸附.     

The adsorption of cyclic hydrocarbons on Ru(001): II. Cyclohexane

The adsorption of cyclohexane on Ru(001) at 90 K has been investigated by thermal desorption mass spectrometry, EELS, UV photoemission and LEED. Thermal desorption indicates the adsorption of the undissociated molecule first in a chemisorbed monolayer (T_d = 200 K) with subsequent formation of multilayers (T_d = 165 K) at higher exposures. The vibrational spectrum obtained by EELS is characterized by a frequency shift of the C-H stretching mode from 2920 cm^?1 (multilayer) to 2560 cm^?1 for the chemisorbed monolayer. Off-specular EELS data indicate two different electron scattering mechanisms for the C-H stretching mode. Whereas for the C-H stretching mode of the multilayer, large angle electron impact scattering is observed, the C-H soft-mode of the monolayer is largely due to small angle dipolar scattering. The He I photoelectron spectra of cyclohexane multilayers are characteristic of the undissociated molecule. A new assignment of C(2s) and the lowest C(2p) level, based on a comparison with benzene, shows that the chemisorbed monolayer is characterized by the absence of emission or broadening of the 2a_1u level. This is attributed to C_3v symmetry of the chemisorbed layer and to a possible interaction of the 2a_Iu orbital with the metal surface.     

One- and two-dimensional S=12 Heisenberg antiferromagnetism in Cu(C5H5NO)6 (ClO4)2 and Cu(C5H5NO)6 (BF4)2, respectively

Specific-heat data on CuL₆(ClO₄)₂ and CuL₆(BF₄)₂ in the temperature range 0.05 < T < 20 K are presented (L ≡ C₅H₅NO). The magnetic contributions are found to have the form of broad maxima, occurring near 1 K. Small χ-type anomalies are observed at T_c = 0.62 ± 0.01 K and 0.142 ± 0.002 K for CuL₆(BF₄)₂ and CuL₆(ClO₄)₂, respectively. The analyses show the magnetic structure to be an assembly of weakly coupled antiferromagnetic chains or layers for CuL₆(ClO₄)₂ and CuL₆(BF₄)₂, respectively. For CuL₆(ClO₄)₂ the intrachain exchange constant is J/K = -1.02 ± 0.02 K, for CuL₆(BF₄)₂ the intralayer exchange constant is J/K = -1.10 ± 0.02 K. Additional evidence for the lower-dimensional magnetic structures is obtained from the temperature dependences of the antiferromagnetic susceptibilities. The data on CuL₆(BF₄)₂ clearly indicate the absence of a divergence in the specific heat for the quadratic-layer Heisenberg antiferromagnet, and provide an estimate for the specific heat for this model. A comparison is made with the corresponding result for the ferromagnetic Heisenberg layer.