Computer Simulation of the Absorption of CO<Subscript>2</Subscript> Molecules by Water Cluster: 2. The Microstructure

The simulation of the absorption of CO₂ molecules by the (H₂O)₁₀ cluster is performed by the molecular dynamics method using the modified TIP4P model of water. The detailed structure of (CO₂)_i(H₂O)₁₀ clusters (0≤i≤11) is analyzed by the statistic geometry method based on the construction of the Voronoi polyhedra. The obtained distributions of the geometric elements of polyhedra indicate the significant changes in the structure of a cluster after the absorption of one CO₂ molecule. Only polyhedra characterizing the structure of unstable water clusters that absorbed six or seven CO₂ molecules demonstrate a nonsphericity close to the ideal tetrahedron. Linear CO₂ molecule tends to be oriented in a cluster so that the average angle formed by this molecule and permanent dipole moments of water molecules would be equal to about 30°.__________Translated from Kolloidnyi Zhurnal, Vol. 67, No. 3, 2005, pp. 315–321.Original Russian Text Copyright © 2005 by Galashev, Rakhmanova, Chukanov.     

ESR study of the radiolysis of polycrystalline benzene-2,1-diazoquinone-4-sulphonic acid

Electron spin resonance spectra of free radicals formed in the radiolysis of benzen-2,1-diazoquinone-4-sulphonic acid in polycrystalline form have been recorded. Two different radical species were found; the first one was stable at 77 K, whereas the second one was formed at higher temperatures. The thermal stability of the latter was investigated in the 20–100 °C temperature range, and the kinetic parameters for the decomposition process were determined. An appropriate mechanism of radiolysis was proposed.     

Investigation of trifluoroacetolysis of some 2-bromoethanol arylsulfonates

Conclusions By PMR spectroscopy the kinetics of trifluoroacetolysis of 2-bromoethyl-2,2-d₂-toluene and 2-bromoethyl-2,2-d₂-anisole sulfonates, the dependence of rate constant on the presence of lithium perchlorate and on salts with a common ion were investigated. The trifluoroacetolysis of 2-bromoethyl-2,2-d₂-toluene-d₇-sulfonate in the presence of the lithium salt of nondeuterated toluenesulfonic acid was investigated. It was shown that reaction is accompanied by isomerization of the initial sulfonate (1,2-migration of bromine) and occurs by an ion pair mechanism.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 371–375, February, 1987.     

Gas-chromatographic determination of 1-(2-chloroethyl)-3-(trans-4-methylcyclohexyl)-1-nitrosourea in plasma after reaction with trifluoroacetic anhydride

The reaction of 1-(2-chloroethyl)-3-(trans-4-methylcyclohexyl)-1-nitrosourea (methyl-CCNU) with trifluoroacetic anhydride is reported. Gas-liquid chromatography of the resulting trifluoroacetyl derivative is applied to determine methyl-CCNU in plasma with a limit of detection of 1.5 μg ml^?1.     

Zur Behandlung induktiv wirksamer Gruppen in der LCAO-MO-Methode (Hückelmethode), 1. Mitt.: Allgemeine Theorie

Zusammenfassung Der induktive Effekt einer an ein aromatisches oder konjugiertes System gebundenen GruppeG wird durch die Änderung desCoulombintegrals desjenigen C-Atoms, an das die GruppeG direkt gebunden ist, berücksichtigt, indem für dieses _s = + angesetzt wird. Der den induktiven Effekt quantitativ beschreibende Parameter kann aus UV-Spektren abgeleitet werden. Die Prozedur dieser halbempirischen Bestimmung von wird allgemein beschrieben und begründet.Mit 1 AbbildungDie wesentlichen Teile dieser Arbeit wurden während meiner Zugehörigkeit zur Quantum Chemistry Group des Mathematical Institute, University of Oxford, im Studienjahr 1957/58 ausgeführt. Vgl. Progress Report, Session 1957–1958, S. 26.     

Addition dipolaire-1,3 aux olefines portant une substitution captodative: reactivite comparee des α et des β amino acrylnitriles vis a vis des arylazides.

Arylazides reacted with α amino-acrylonitriles $\text{1}$ to produce 1-aryl-5-amino-triazoles, and with β amino-acrylonitriles $\text{2}$ to give 1-aryl-4-cyanotriazoles. Kinetics showed the Hammett ρ to be > o and therefore, these reactions are controlled by LUMOazide-HOMOolefin interaction. Despite the captodative substitution in $\text{1}$ and $\text{2}$ (ΔΔ E^≠～ 500 cal.M^?1) does'nt agree with a diradical intermediate.     

Acylation of norcarane and its derivatives by pivaloyl tetrafluoroborate

Conclusions The decomposition of the complex obtained in the reaction of pivaloyl tetrafluoroborate with norcarane and its 1-methyl and 1-phenyl derivatives by water gives 1-hydroxy-3-pivaloyl derivatives of cyclohexanes and the corresponding unsaturated ketones. The hydride decomposition of the same complex leads to derivatives of 6-oxabicyclo[3.2.1]octane.For preliminary report see [1].Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2512–2518, November, 1976.     

New heterocyclic sym-triazolopyrimidinium systems — Quinoline,pyridazine, and phthalazine derivatives

Pyrimido[1′,2′:1,5]-sym-triazolo[4,3-b]pyridazinium, pyrimido[1′,2′:1,5]-sym-triazolo-[4,3-b]phthalazinium, and pyrimido[1′,2′:1,5]-sym-triazolo[4,3-a]quinoliniumsalt derivatives were obtained by condensation of 3-amino-sym-triazolo[4,3-b]pyridazinium, 3-amino-sym-triazolo[3,4-a]phthalazinium, and 1-amino-sym-triazolo[4,3-a]quinolinium salts with β-diketories and 1,1,3,3-tetraethoxypropane. The structures of the reaction products were confirmed by the P MR spectra.