Computer simulation of mechanical properties of carbon nanostructures

The aim of the present paper is the theoretical investigation of the mechanical properties of carbon nanostructures of graphene and single-wall carbon nanotubes by using nanoscopic and macroscopic approaches. The nanoobject structures in free and deformed states were considered and the corresponding energies were computed in the framework of quantum mechanics methods by using the original software package of semi-empirical programsNDDO/sp-spd (developed in the Institute of Applied Mechanics, Russian Academy of Sciences) in parallel computations. The nanostructural deformations were prescribed in the approximation of the mechano-chemical deformation coordinate. The deformation forces were described by the energy gradients in selected coordinates of microscopic deformations. The mechanical characteristics of nanoobjects such as Young’s modulus, rigidity coefficients, works done in deformation, critical stresses, and relative elongations in fracture were calculated in the framework of the macroscopic linear theory of elasticity; the deformation forces determined by quantum mechanical calculations were used in the corresponding relations. It was found that the mechanical characteristics of single-wall carbon nanotubes (CNT) depend on their diameter and chirality, and the deformation properties of a graphene sheet are asymmetric with respect to two normal extension modes directed along the “zigzag” and “armchair” on the sheet edges. The calculated mechanical characteristics are in good agreement with the experimental data known fromthe literature, in both the values and the deformation asymmetrywith respect to different deformation modes.     

New approach to the synthesis of fenestrane derivatives

Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, p. 2876, December, 1988.     

Crystal and molecular structure of 6-phenyl-6-thioxo-6-phosphatetracyclo[8.6.1.0.1.509.13]heptadecane-14,17-dione

Institute of Chemical Sciences of the Kazakh SSR and Institute of Heteroorganic Compounds, Academy of Sciences of the USSR. Translated from Zhurnal Strukturnoi Khimii, Vol. 30, No. 6, pp. 159–162, November–December, 1989.     

Synthesis,structures, and redox properties of some new dithiocarbamates that include a heteroaromatic ring

New Cu, Ni, Pb, Zn, Co. Fe, Mn, Sb, and Bi dithiocarbamates that include 2-thenyl and 2-furfuryl radicals were synthesized. The potentials of polarographic oxidation on a rotating platinum electrode were determined for them and for the previously synthesized N-substituted unsymmetrical dithiocarbamates of the same metals. The results of x-ray diffraction analysis of bis-(di-2-thenyldithiocarbamato)nickel(2⁺) are presented and discussed.Deceased.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 902–909, July, 1987.     

X-Ray diffraction structural analysis of bis(N-oxide-N′-methoxydiazenyl)-methylmethane and bis(N-oxide-N′-methoxydiazenyl)(N″-methyl-N″-nitraminomethyl)-methane

Conclusions An x-ray diffraction structural investigation of bis(N-oxide-N-methoxydiazenyl)methane and bis-(N-oxide-N-methoxydiazenyl)(N-methyl-N-nitroaminomethyl)methane showed that each of the alkoxydiazene oxide fragments in both molecules has Z configuration.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1200–1202, May, 1989.     

Fluorosubstituted rhodacarboranes 3,4-(R3P)2-3-H-3,1,2-RhC2B9H11−n F n (n=1, 2, 4): Synthesis, molecular structure, and catalytic properties in hydrosilylation of styrene and phenylacetylene

Hydridorhodacarboranes 3,3-(Ph₂RP)₂-3-H-3,1,2-RhC₂B₉H_11−n F _n (R=Ph, Me;n=1, 2, 4) containing F atoms at the B atoms of the π-carborane ligand were synthesized from (Ph₃P)₃RhCl or (Ph₂MeP)₃RhCl andnido-7,8-C₂B₉H_12−n F _n ⁻ (n=1, 2, 4) salts. Hydridorhodacarboranes 3,3-(Ph₂MeP)₂-3-H-3,1,2-RhC₂B₉H_11−n F _n readily exchange the H atom at the Rh atom for the Cl atom under the action of CH₂Cl₂ to give 3,3-(Ph₂MeP)₂-3-Cl-3,1,2-RhC₂B₉H_11−n F _n . The structures of the 3,3-(Ph₃P)₂-3-H-3,1,2-RhC₂B₉H₇F₄ and 3,3-(Ph₂MeP)₂-3-Cl-3,1,2-RhC₂B₉H₉F₂ complexes were determined by X-ray diffraction analysis. Catalytic properties of the rhodacarbonanes obtained in hydrosilylation of styrene and phenylacetylene by PhMe₂SiH were studied. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 570–578, March, 1997.