Molecular mobility in hydrogels based on poly(acrylic acid) and macrodiisocyanates

Partially water-swellable polymer networks were synthesized on the basis of poly(acrylic acid) and various macrodiisocyanates. Hydrophilic and hydrophobic local regions were revealed in swollen networks (hydrogels) by means of the spin probe technique. The local mobility in hydrophobic regions depends on the macrodiisocyanate structure; however, it is substantially lower than that in hydrophilic regions for all gels. It was assumed that the presence of hydrophobic and hydrophilic regions and the difference in their local dynamics must have a substantial effect on the pharmacokinetics of release of drugs immobilized in these hydrogels.     

Quantum-Chemical Study of Structural and Energy Characteristics of Benzonitrile Dimers

Ab initio MP2 calculations with several basis sets proved the existence of a stable benzonitrile dimer with a planar structure and a short contact between the H atom of one molecule and the N atom of another. The structure is greatly stabilized by attraction between the neighboring oppositely directed dipoles and donor-acceptor interaction between the orbital of the lone electron pair of the N′ atom and the vacant antibonding orbital localized on the C-H bond.Original Russian Text Copyright © 2004 by O. V. Sizova, E. P. Sokolova, V. I. Baranovskii, D. A. Rozmanov, and O. A. Tomashenko__________Translated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 5, pp. 807–815, September–October, 2004.     

Four-Dimensional Lie Group Integration of the Klein–Fock Equation

A method of four-dimensional Lie group integration of the Fock–Klein equation is described in the present paper. The method is based on the formalism of co-adjoint representation orbits and on the non-commutative integration method. Right-invariant metrics being solutions of the Einstein equation are also classified for manifolds of four-dimensional Lie groups.     

Role of carbon clusters in pyrolysis of iodomethanes

Molecular parameters and thermodynamic functions of the carbon cluster cyclo-C₁₂ were calculated by the B3LYP method in the aug-cc-pVDZ basis. The composition of products of iodomethane pyrolysis in the range 500–1000 K was calculated from the data obtained in combination with published data on thermodynamic function of other molecules. High experimental yield of methane and carbon (carbyne) in the iodomethane pyrolysis and the absence of even traces of ethane, 1-iodoethane, and 1,2-diiodoethane were accounted for.     

Synthesis and properties of fluorinated 2-benzoylcyclohexane-1,3-diones

Fluorinated 2-benzoylcyclohexane-1,3-diones were obtained by the O-C isomerization of the corresponding 3-benzoyloxycyclohex-2-en-1-ones under the action of acetone cyanohydrin in the presence of triethylamine in the medium of absolute acetonitrile. The structure of the target compounds was investigated by the means of IR and NMR spectroscopy, and X-ray diffraction analysis.     

Use of the CNDO method for the study of the electronic structure and properties of complexes of the transition metals

Conclusions In our view, the material examined in the present review indicates that, in spite of the appearance of more accurate methods of calculating the electronic structure and the increasing possibilities provided for their realization for fairly complex systems, the applied value of simple semiempirical methods, in particular the CNDO method, is far from exhausted. In the near future, semiempirical calculations will probably provide the chief means of studying the electronic structures of complex molecules, by becoming accessible to an increasing circle of chemists.Leningrad State University. Translated from Zhurnal Strukturnoi Khimii, Vol. 17, No. 3, pp. 549–577, May–June, 1976.     

Indo calculation of electronic spectra for transition metal complexes in the extended approximation of singly excited configurations

Semiempirical INDO-E/S calculations of [RuX₆]^q (X=NH₃, q=+2, +3; X=CN⁻, q=−4, −3) complexes are performed to demonstrate that the MO relaxation in the electronically excited state can be taken into account by introducing certain double excitations into the configuration interaction matrix; the principles of selection of the excitations are discussed. The calculation results are compared with the experimental electronic absorption spectra. St. Petersburg State University. Translated fromZhurnal Struktumoi Khimii, Vol. 37, No. 2, pp. 195–205, March–April, 1996. Translated by I. Izvekova     

Highly effective dehydrogenation of steroid isoxazolines

Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 852–853, June, 1990.