The remarkable chemistry of trannulenes: green fluorinated fullerenes with unconventional aromaticity

We report the first reaction of trannulenes involving their thermal isomerization to a new class of compounds termed "triumphenes". The thermodynamically controlled conversion of trannulenes into triumphenes is accompanied by an unprecedented migration of three organic addends from one hemisphere of the fullerene cage to another. The reaction products, bearing aliphatic substituents, might find applications in materials science as strong electron acceptors due to the presence of fifteen electron-withdrawing fluorine atoms in their molecular framework. It was revealed that the isomerization of trannulenes can be affected by the presence of unsaturated compounds in the reaction mixture. Heating of trannulenes C(60)F(15)R(3) with C(60), C(70), anthracene, or pentacene at reflux in 1,2-dichlorobenzene yields fluorinated derivatives C(60)F(14)R(2)A, which possess a fused cyclic addend A. The products of this reaction have "triumphene-type" addition patterns and seem to be formed through an unprecedented sequence of elimination, addition, and isomerization steps. The molecular structure of a representative triumphene was proven unambiguously by X-ray single-crystal diffraction analysis and by NMR spectroscopy. The reactions revealed here open up numerous opportunities for chemical derivatization of fluorinated fullerenes. This method promises to provide a new path towards valuable photoactive materials and a new generation of fullerene-based compounds that are suitable for biomedical applications.     

Copper(I) coordination compounds with closo-dodecaborate anion

Copper(I) complexes with a closo-dodecaborate anion were synthesized: Cat[CuB₁₂H₁₂], where Cat = Cs⁺, Ph₄P⁺, Ph₄As⁺, or R _x NH _4?x ⁺ (R = Me, Et, Pr, or Bu; x = 3 or 4). The complexes were synthesized from the copper(II)-closo-dodecaborate-sulfur dioxide (sodium sulfite) system. The structure of [Cu₂(NCCH₃)₄B₁₂H₁₂] was determined using X-ray crystallography.     

Refined Orthotropic Plate Motion Equations for Acoustoelasticity Problem Statement

The formulation of the acoustoelasticity problem is given on the basis of refined motion equations of orthotropic plates. These equations are constructed in the first approximation by reducing the three-dimensional equations of the theory of elasticity to the two-dimensional equations of the theory of plates, where the approximation of the transverse tangential stresses and the transverse reduction stress is made with the help of trigonometric basis functions in the thickness direction. Wherein at the points of the boundary (front) surfaces, the static boundary conditions of the problem for tangential stresses are satisfied exactly and for transverse normal stress — approximately. Accounting for internal energy dissipation in the plate material is based on the Thompson—Kelvin—Voigt hysteresis model. In case of formulating problems on dynamic processes of plate deformation in vacuum, the equations are divided into two separate systems of equations. The first of these systems describes non-classical shear-free, longitudinal-transverse forms of movement, accompanied by a distortion of the flat form of cross sections, and the second system describes transverse bending-shear forms of movement. The latter are practically equivalent in quality and content to the analogous equations of the well-known variants of refined theories, but, unlike them, with a decrease in the relative thickness parameter, they lead to solutions according to the classical theory of plates. The motion of the surrounding the plate acoustic media is described by the generalized Helmholtz wave equations, constructed with account of energy dissipation by introducing into consideration the complex sound velocity according to Skudrzyk.     

The low-temperature heat capacity and saturation vapor pressure of ethyl ester of butanoic acid

The heat capacity, thermodynamic properties of fusion, and purity of the ethyl ester of butanoic acid were determined by adiabatic calorimetry in the temperature range from 8 to 372 K. The pT-parameters of the ester for the equilibrium liquid-vapor were measured by comparative ebulliometry in the “atmospheric” range of pressure from 10.8 to 101.7 kPa. The obtained data were used to derive the normal boiling temperature (T _n.b), the enthalpies of vaporization at T = 298.15 K and T _n.b, and the main thermodynamic functions (changes of S, H, G) in the crystal and liquid states of the temperature interval studied and in the ideal gas state at T = 298.15 K. The experimental vapor pressures of the narrow temperature interval, ΔT = 62 K were extended to the entire range of the liquid, T _cr − T _tp⁰ = 394.3 K, from the triple, T _tp⁰, to the critical, T _cr, temperatures.     

Mass transfer effects in preparative chromatography of eremomycin on polymeric sorbents

This work is devoted to the study of the regularities of the sorption of the new antibacterial antibiotic eremomycin on carboxylic sorbents. The main sorption kinetic equilibrium and dynamic parameters for realization of one-act preparative chromatographic process were determined and the difference between gel-like and structurally segregated carboxylic cation exchangers was analyzed. The optimal conditions for sorption and complete desorption of eremomycin were found.     

Replacement of Fe atoms by Ru in a carbidocarbonyl cluster [Fe<Subscript>6</Subscript>C(CO)<Subscript>16</Subscript>]<Superscript>2−</Superscript>. Structures of reaction products

The reaction of the carbidocarbonyl cluster [Fe₆C(CO)₁₆]²⁻ with ruthenium(IV) hydroxochloride Ru(OH)Cl₃ was studied. At 90–100 °C, the reaction gave products of replacement of Fe atoms by Ru in the [Fe₆C(CO)₁₆]²⁻ cluster along with degradation products. Treatment of the replacement products with FeCl₃ afforded the [Fe_2.96Ru_3.04C(CO)₁₇] compound (1), which was characterized by X-ray diffraction analysis. The crystals of cluster 1 are composed of two types of octahedral molecules (1a and 1b) in a ratio of 2 : 1. Molecules 1a are in general positions, and molecules 1b are located on twofold axes. In both molecules, the Fe and Ru atoms are disordered over four of six positions. __________ Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1761–1766, August, 2005.     

Crystal and molecular structure of barium cyclohexane-1,2-diamine-<Emphasis Type="Italic">N,N,N′,N′</Emphasis>-tetraacetatonickeloate decahydrate Ba[Ni(<Emphasis Type="Italic">Cdta</Emphasis>)] · 10H<Subscript>2</Subscript>O

The X-ray diffraction study of Ba[Ni(Cdta)] · 10H₂O is performed (R1 = 0.0441 for 5136 observed reflections). The crystals are triclinic, a = 8.833(2) Å, b = 9.025(2) Å, c = 16.922(3) Å, α = 80.56(3)°, β = 82.77(3)°, γ = 76.98(3)°, Z = 2, and space group \(P\bar 1\). The crystal is built of the [Ni(Cdta)]^2? anionic complexes, the [Ba(H₂O)₆]²⁺ hydrated cations, and crystallization water molecules. The distorted octahedral coordination of the Ni atom includes two N and four O atoms of the Cdta^4? ligand (mean Ni-N, Ni-O_G, and Ni-O_R re 2.080, 2.082, and 2.036 Å, respectively). The irregular nine-fold coordination of the Ba atom consists of six O atoms of water molecules and three O(Cdta) atoms from three anionic complexes (Ba—O, 2.715–3.090 Å). With consideration for the bonds with three Ba atoms, the Cdta^4? ligand is octadentate (2N + 6O) and fulfills the pentadentate μ₄-bridging function. The structural units are linked through an extended network of hydrogen bonds.