Regioselective hydrogen-deuterium exchange in the [B10H10]2– anion. Syntheses of [1,10-B10H8D2]2– and [2,3,4,5,6,7,8,9-B10H2D8]2–

Decahydro-closo-decaborate anion, [B₁₀H₁₀]^2–, undergoes regioselective deuterio-exchange in methanol-d₄. Selectively deuterated derivatives [1,10-B₁₀H₈D₂]^2– and [2,3,4,5,6,7,8,9-B₁₀H₂D₈]^2– were synthesized.     

Ynaziridines. Methods of synthesis of a new type of ynamines

Ways of synthesizing ynaziridines by successive halogenation and dehydrohalogenation of enaziridino esters, the reaction of potassium aziridinide with bromophenylacetylene, the reaction of 1H-aziridines with the methyl ester of bromopropionic acid was studied. The different direction of the reaction of aziridines with bromomethylpropiolate as a function of the nature of the solvent was demonstrated. In methanol the addition of aziridine to the triple bond proceeds stereospecifically with the formation of the E-isomer. When this reaction was conducted in ether, ynaziridines were obtained for the first time. An effective method of synthesis of ynaminoesters was developed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1492–1496, November, 1984.     

Synthesis of the cationic complexes [(C5H4CPh2)2Ru]2+ and [Ph2(HO)CC5H4RuC5H4CPh2]+. Molecular and crystal structures of [Ph2(HO)CC5H4RuC5H4CPh2]+[CF3SO3]− · CHCl3 and [C5H5RuC5H4CPh2]+PF6 −

The formation of the previously unknown [(C₅H₄CPh₂)₂Ru]²⁺ dication was established by¹H and¹³C NMR spectroscopy. This cation readiiy hydrolizes to form the monocation, [Ph₂(HO)CC₅H₄RuC₅H₄CPh₂]⁺. The latter was characterized by NMR spectroscopy and X-ray structural analysis. For comparison, [C₅H₅RuC₅H₄CPh₂]⁺PF₆ ^? was also studied by X-ray structural analysis. The increase in the M-C_α distance and the decrease in the angle of inclination of the CPh₂ group to the metal atom in disubstituted ruthenocene compared to those in monosubstituted ruthenocene is related to the presence of a bulky substituent in the second Cp ligand and is likely due to the crystal packing effect. IR spectra and X-ray structural analysis attest to the existence of the OH ? OSO₂CF₃ hydrogen bond in crystals of the trifluoromethanesulfonate monocation.     

Solid-phase reaction of organometallic derivatives of nitrophenols,P-nitrothiophenol,andP-nitroaniline with bromides,according to the molecular spectroscopy data

The effect of the visualization of the reaction of bromide anion with PhHg- and PPh₃Auderivatives of phthalein has been extended to the organometallic derivatives (M=Hg, Au, Sn, Pb, Sb) of other classes of indicators: nitrophenols, nitrothiophenol, and 4-nitrobenzenesulfonylanilide. On the basis of the analysis of the electronic reflection spectra and the IR spectra it has been found that the changes occurring upon the reaction of these compounds with bromides are determined by the formation of complexes and/or anions and are more pronounced in the latter case. The character of the interaction depends on the dissociation ability of the M-X bonds (which was determined earlier while studying the reaction with DMSO), the ability to form complexes, and on the steric hindrance which has proved to be considerable in the solid-phase reaction (with Br^–).Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 1974–1977, November, 1993.     

Hydrogen bonds and protonation of carbonyl-containing polynuclear rhodium complexes

According to IR spectroscopy data, the interaction of bi-, tri-, and tetranuclear cyclopentadienylcarbonyl rhodium complexes with rather weak protic acids (phenols, fluoroalcohols) in low-polarity media results in the formation of hydrogen bonds of the OH...O=C type with bridged carbonyl groups. According to¹H NMR data, protonation of these complexes with strong acids (CF₃COOH and HBF₄) occurs at the the Rh-Rh bond to give the symmetrical bridge.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 386–388, February, 1995.This work was carried out with the financial support of the Russian Foundation for Basic Research (Project No. 93-03-0461).     

Optimizing Instrumental Neutron Activation Analysis of Extraterrestrial Materials: Fragments of Lunar Rocks, Meteorites, Chondrules, and Ultrarefractory Inclusions

A previously developed approach to the optimization of instrumental neutron activation analysis based on the simulation of gamma spectra of samples of the specified composition was extended to the analysis of samples of cosmic origin differing in chemical composition, including samples of small mass (0.01 mg) and dimensions (100 m). The approach was justified by comparing the results obtained with the published data.     

Mechanisms of C—H Activation in Alkanes by Chromium-Oxo Reagents

The mechanisms of activation of a C—H bond by chromium-oxo reagents in the reactions of methane, isobutane, adamantane, and protoadamantane with CrO₂(OH)₂ were investigated by the BH&HLYP quantum-chemical method in the 6-31G^* and 6-311G^** (for Cr) basis sets. It was shown that the transition states have clearly defined biradical character and significant transfer of charge from the hydrocarbon to the electrophile.     

Excitonic Emission in van der Waals Nanotubes of Transition Metal Dichalcogenides

Nanotubes (NTs) of transition metal dichalcogenides (TMDs), were first synthesized more than a quarter of a century ago; nevertheless, many of their optical properties have so far remained basically unknown. Herein, the state of the art in the knowledge of the optical properties of TMD NTs is presented. First, general properties of multilayered crystals are evaluated, and available data on related NTs are analyzed. Then, the technology for the formation and the structural characteristics of NTs are represented, focusing on the structures synthesized by chemical transport reaction. The core of this work is the presentation of the ability of synthesized TMD NTs to emit bright photoluminescence (PL), which has been discovered recently. By means of micro‐PL spectroscopy of individual tubes, we show that excitonic transitions relevant to both direct and indirect band gaps contribute to the emission spectra of the NTs despite having the dozens of monolayers in their walls. The performance of the tubes as efficient optical resonators is highlighted, where confined optical modes strongly affect the emission. Finally, a brief conclusion is presented, along with an outlook of the future studies of this novel radiative member of the NTs family, which have unique potential for different nanophotonics applications.