Dynamics of a Lüders Band and Destruction of an Aluminum-Magnesium Alloy,Initiated by a Stress Concentrator

Spatio-temporal localization of deformation and the rupture of the aluminum-magnesium AlMg6 alloy, initiated by a geometrical stress concentrator, are studied in situ by video recording at a speed of 500 to 20000 frames/s. It is established that a stress concentrator in the form of a small notch with a depth about 1% of the width of a flat specimen is an attractor of bands of macrolocalized plastic deformation, starting from a Lüders band and ending with the start of the main crack. The key role of intersecting deformation macrobands in the development of the main crack is revealed. Possible micromechanisms of viscous destruction associated with the dynamics of the intersection of deformation bands are discussed.     

Synthesis of hexachlorobicyclo[2.2.1]hept-5-enylmethyl haloacetates

Russian Journal of Applied Chemistry - The possibility of preparing hexachlorobicyclo[2.2.1]hept-5-enylmethyl haloacetates by reactions of hexachlorocyclopentadiene with allyl haloacetates was...     

Serrated creep and spatio-temporal structures of macrolocalized plastic deformation

The dynamics and morphology of macrolocalized deformation bands have been investigated using a complex of high-speed in situ methods under the conditions of serrated creep of flat samples of the aluminum-magnesium alloy 5456 with different aspect ratios. It has been found that, at the front of a macroscopic plastic deformation jump, a complex structure of propagating deformation bands, which are considered as macrolocalized deformation “quanta,” is spontaneously formed in the material. It has been shown that, with an increase in the sample length, the deformation behavior of the alloy tends to the state of self-organized criticality.     

Synthesis of methyleneoxyamino derivatives of 1-butylthioheptane

The possibility of synthesizing new methyleneoxyamino derivatives of 1-butylthioheptane was investigated. The structure of the synthesized compounds was proved by elemental analysis and IR and ¹H NMR spectroscopy. Some representatives of the synthesized compounds were tested as antimicrobial lubricant additives, and also as antiseptic materials against bacteria and funguses.     

Synthesis of 2-aminomethoxy-1-benzylsulfanylpentanes

Mannich condensation of 1-benzylsulfanylpentane with equimolar amounts of formaldehyde and secondary amine gave in 3–4 h at 45–50°C the corresponding 2-aminomethoxy-1-benzylsulfanylpentanes in 72–76% yield.     

Influence of the nature of ligands in iridium complexes with C60 fullerene and ·P(O)(OPri)2, ·CMe3, and ·CCl3 radicals on regioselectivity of addition and stability of spin-adducts formed: an EPR study

The addition of ^·P(O)(OPrⁱ)₂ (R¹), ^·CMe₃ (R²), and ^·CCl₃ (R³) radicals to metallofullerenes (η²-C₆₀)IrH(CO)(CNBu^t)₂(o-HCB₁₀H₉CCH₂PPh₂-B,P) (1), (η²-C₆₀)IrH(CO)(DIOP) (DIOP is (4R,5R)-(+)-4,5-bis(diphenylphosphinomethyl)-2,2-dimethyl-1,3-dioxolane, 2), and (η²-C₆₀)IrH(CO)(PPh₃)₂ (3) was studied by EPR spectroscopy. A stability study of spin adducts (SAs) of R¹ radicals with complexes 1 and 2 showed that when the reactions are initiated by illumination with 366-nm light, the EPR spectra exhibit only signals of those isomers that are formed upon attack of the R¹ radicals on the carbon atoms of the cis-1 and cis-2 bonds (i.e., carbon atoms of the fullerene hemisphere to which the metallofragment is attached). Investigations of the reactions of R² and R³ radicals with complexes 1–3 initiated with 366-nm light made it possible to detect (i) regioisomers formed by adding these radicals to carbon atoms of the cis-n bonds and (ii) SAs formed by adding the radicals to carbon atoms of other bonds in complexes 1–3. The hyperfine structure of the EPR spectrum essentially depends on the spatial structure of substituents at the metal atom and allows individual regioisomers of not only phosphoryl radicals, but also carbon-centered radicals R² and R³ with metallofullerenes 1–3 to be identified. The rate constants for addition of R² and R³ radicals to complexes 2 and 3 were determined. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1302–1309, July, 2007.     

Solvent-free oxidation of aliphatic alcohols with ceric ammonium nitrate—lithium bromide system

Esters are formed during the solvent-free oxidation of primary aliphatic C₅–C₉ alcohols with Ce(NH₄)₂(NO₃)₆–LiBr, whereas secondary octan-2-ol gives a mixture of isomeric 1-and 3-bromooctan-2-ones. Dedicated to Academician V. A. Tartakovsky in honor of his 75th anniversary. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1445—1450, August, 2007.     

Homolytic reactive mass spectrometry of fullerenes: interaction of C60 and C70 with ketones in the electron impact ion source of a mass spectrometer and the comparison of results with those of photochemical reactions of C60 with several ketones in solution

Our previous investigations showed that homolytic reactions of C₆₀ with a number of perfluoroorganic and organomercury(II) compounds occurring under electron impact (EI) in the ionization chamber (IC) of a mass spectrometer could predict the reactivity of C₆₀ towards these compounds in solution or solid state. To expand the scope of this statement, C₆₀ and C₇₀ have been reacted with ketones RCOR₁, where R and R₁ are alkyl, aryl, benzyl, and CF₃, in an IC under EI to yield products of the addition of R^· and R₁^· radicals to the fullerenes, paramagnetic ones being stabilized by hydrogen addition and loss. Experimental evidence in support of a mechanism involving homolytic dissociation of ketone molecules via superexcited states to afford these radicals that react with the fullerenes at the IC surface has been obtained. As anticipated, the reactions between C₆₀ and several ketones conducted in solution under UV irradiation have afforded Me-, Ph-, and CF₃-derivatives of C₆₀. However, some other products have been identified by mass spectrometry and their formation is reasonably explained. When decalin has been employed as a solvent, decalinyl derivatives of the fullerene have been found among the products and the (9-decalinyl)fullerenyl radical has been registered by EPR. Thus, incomplete but reasonable conformity of the results of the reactions of fullerenes with ketones in an IC under EI with those of the reactions of the same reagents in solution under UV irradiation has been demonstrated, and the former results can predict the latter ones to a reasonable extent.