E and Z stereoisomers of compounds of the phthalide series

The stereospecific position of the H⁴ proton in the PMR spectra of 3-benzyl-idenephthalides identifies unambiguously the E and Z isomers in a mixture. The IR spectra of off-planar deformation vibrations of the C=C bond in the 990–970 cm^–1 region have strong absorption bands, assigned to the E and Z isomers. The strong short-wave band (260 nm) for 3-benzylidenephthalides, having only one benzene ring in the indan moiety, suggests the presence of the E form (=28,000). The long-wave absorption band at 390–430 nm belongs to the Z isomers (=21,000–31,000). 3-Benzylidenephthalides which have no carbonyl groups in their molecules, show fluorescence (_f1=540–560 nm in EtOH).N. N. Semenov Institute of Chemical Physics, Russian Academy of Sciences, 117977 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 2, pp. 309–314, February, 1992.     

Synthesis of potential antineoplastics by condensation of phthalic anhydride with 4-bis(2-chloroethyl)aminophenylacetic acid

Indandione, its enol acetate, and the products of a parallel reaction — a mixture of isomeric acidsE, Z-5, and phthalide — are formed in the reaction of substituted phenylacetic acid with phthalic anhydride in acetic anhydride and triethylamine. 2-Substituted indandione derivatives were obtained.N. N. Semenov Institute of Chemical Physics, Russian Academy of Sciences, 117977 Moscow. Institute of Chemical Physics in Chernogolovka, Russian Academy of Sciences, 142432 Chernogolovka. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 11, pp. 2609–2617, November, 1992.     

Use of thin collodion films to prevent recoil-ion contamination of alpha-spectrometry detectors

Recoil ions from alpha-particle emission can contaminate surface-barrier detection systems. This contamination results in increased measurement uncertainty, and may require the replacement of expensive detectors. Disposable thin Collodion films are easily prepared and effectively retard the recoil ions when either directly applied to the surface of alpha-sources or as catcher foils between the source and the detector. The thin films are particularly effective for relatively low-level sources, but can sustain structural damage when exposed to high levels of recoil ions (tens of thousands per second) over extended periods of time.     

An oxidative alkylamination of 1,3,7‐triazapyrenes in the aqueous medium

1,3,7‐Triazapyrene and 2‐methyl‐1,3,7‐triazapyrene have shown to react with a wide range of alkylamines in the presence of an oxidant (K₃Fe(CN)₆) in the water solution at room temperature to give rise to the corresponding 6‐mono‐alkyl(dialkyl)amino‐ and 6,8‐bis‐dialkylamino derivatives. J. Heterocyclic Chem., (2011).     

A kinetic model for limonene oxidation

The kinetic regularities of the autooxidation of R(+)−limonene (LH) were experimentally studied at various temperatures. A kinetic model including the main elementary reactions and the corresponding rate constants was developed. The degenerate chain branching during limonene oxidation proceeds via bimolecular reactions and involves hydroperoxide LOOH + LH → L· + LO· + H₂O and LOOH + LOOH → LO· + LO₂ · + H₂O. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 80–86, January, 2008.     

Autooxidation of tetrachlorohydroquinone in aqueous media

The oxidation of tetrachlorohydroquinone in an aqueous solution at pH 7.40 is an autocatalytic reaction (signoid kinetic curves). The interaction of the tetrachloro-1,4-semiquinone radical anion with dioxygen occurs with the rate constantk ₂ equal to 9±3 L mol⁻¹ s⁻¹ (22–37°C). Superoxide dismutase does not affect the maximum rate of tetrachlorohydroquinone oxidation. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 890–895, May, 1999.     

Building capacity for undergraduate education and training in computational molecular science: A collaboration between the MERCURY consortium and the Molecular Sciences Software Institute

The Molecular Sciences Software Institute (MolSSI) is an National Science Foundation (NSF) funded institute that focuses on improving software, education, and training in the computational molecular sciences. Through a collaboration with the Molecular Education and Research Consortium in Undergraduate computational chemistRY (MERCURY), the MolSSI has developed resources for undergraduate and other early career students to lay an educational foundation for the next generation of computational molecular scientists. The resources focus on introducing best practices in software engineering to students from the very start to make their software more useable, maintainable, and reproducible.     

Growth of Fe<Subscript>3</Subscript>O<Subscript>4</Subscript> films on the Si(111) surface covered by a thin SiO<Subscript>2</Subscript> layer

Magnetite polycrystalline films are grown by variously oxidizing a Fe film on the Si(111) surface covered by a thin (1.5 nm) SiO₂ layer. It is found that defects in the SiO₂ layer influence silicidation under heating of the Fe film. The high-temperature oxidation of the Fe film results in the formation of both Fe₃O₄ and iron monosilicide. However, the high-temperature deposition of Fe in an oxygen atmosphere leads to the growth of a compositionally uniform Fe₃O₄ film on the SiO₂ surface. It is found that such a synthesis method causes [311] texture to arise in the magnetite film, with the texture axis normal to the surface. The influence of the synthesis method on the magnetic properties of grown Fe₃O₄ films is studied. A high coercive force of Fe₃O₃ films grown by Fe film oxidation is related to their specific morphology and compositional nonuniformity.     

Two new methods of synthesis for the perbromate ion: chemistry and determination by LC-MS/MS

Historically, the synthesis of perbromate ion through conventional oxidation routes has proven elusive. Herein, we report perbromate ion formation through the reaction of hypobromite and bromate ions in an alkaline sodium hypobromite solution. Formation was established via LC-MS/MS analysis of the bromate and perbromate ions in the reaction solutions over a 13-day period. Furthermore, it was discovered that the perbromate ion was also formed as a result of the electrospray ionization process. Selective reduction of the bromate ion prior to analysis was used to confirm the two formation pathways.