Supramolecular Systems Based on Ca2+, [Mo3O2S2Cl6(H2O)3]2s-, [Mo3S4Cl6.75Br0.25(H2O)2]3s- and Cucurbit[6]uril

Adducts of cucurbit[6]uril with Ca²⁺ and trinuclear cluster chloroaquacomplexes (H₉O₄)₂(H₇O₃)₂[(Ca(H₂O)₅)2(C₃₆H₃₆N₂₄O₁₂)]Cl₈·0.67H₂O (1) and [(Ca(H₂O)₅)₂(C₃₆H₃₆N₂₄O₁₂)]× [Mo₃O₂S₂Cl₆(H₂O)₃]₂·13H₂O (2) are obtained and structurally characterized. The structures of both compounds contain polymeric [Ca(H₂O) _n ]₂² CB[6]∞ cations that form infinite columns; the space between them is filled with Cl^s- (1) and [Mo₃O₂S₂Cl₆(H₂O)₃]^2s- (2). A new (H₇O₃)₂(H₅O₂)× [Mo₃S₄Cl_6.25Br_0.25(H₂O)₂](C₃₆H₃₆N₂₄O₁₂)·CH₂Cl₂·6H₂O complex (3) is also obtained and structurally characterized.     

Cyclocondensation of methyl 2-(5-methylisoxazol-3-yl)imino-3,3,3-trifluoropropionate with 1,3-binucleophiles

Cyclocondensation of methyl 2-(5-methylisoxazol-3-yl)imino-3,3,3-trifluoropropionate with 1,3-binucleophiles such as benzamidines, aminothiazoline, and 2-aminocrotonic acid nitrile results in trifluoromethyl-containing 3,5-dihydro-4-ones, 2,3-dihydro-6H-imidazo[2,1-b]thiazol-5-one, and 4,5-dihydro-1H-pyrrole-3-carbonitrile.     

Isotope exchange study of the e lectrophilic replacement reaction in a saturated carbon atom

Summary A study of the isotope exchange of the ethyl esters of -brommercuryarylacetic acids with²⁰³Hg Br₂ and 70% aqueous dioxane at 60°, made it possible to arrange the substituents in the following series in order of decreasing reaction rate: p-I, Br, Cl > p-F >H > o-CH₃ > p-CH₃> p-typet. C₄H₉.     

Electronegativity scheme for reactions involving radical addition to vinyl monomers

The concept of the apparent electronegativity of a reaction site has been introduced. This has been used to develop a new scheme for calculating the relative rate constants of addition of radicals with different structures to vinyl monomers. The parameters of the scheme are given for 40 reagents. The results of a comparison of calculated and literature rate constants of addition are presented.Institute of Nonaqueous Solution Chemistry, Russian Academy of Sciences, 150003 Ivanovo. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 10, pp. 2238–2245, October, 1992.     

Standard Enthalpies of Formation for Some Semi-products At the Synthesis of Poly(ethylene) Terephthalate

The enthalpies of combustion for 4-formylbenzoic acid (I), 4-methylbenzyl alcohol (II), and trimethyl 1,2,4-benzenetricarboxylate (III) were determined by the bomb calorimetry method. Enthalpies of sublimation for I and II were measured with a calorimeter. The contributions of different substituents to the standard enthalpies of formation for benzene derivatives in the gas state were derived. This revised version was published online in July 2006 with corrections to the Cover Date.     

A novel polybromide complex of bismuth – (Et4N)3{[Bi2Br9](Br2)}: synthesis and structural features

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Monodisperse spherical meso–macroporous silica particles: Synthesis and adsorption of biological macromolecules

Monodispersed spherical silica particles, including large mesopores (over 10 nm) and macropores (up to 100 nm) were obtained by chemical etching in an autoclave. A method for introducing globular protein myoglobin molecules into the pores is developed. The method of filling is based on a high adsorption capacity of the developed internal pore structure of the particles. The structure and adsorption properties of the materials are studied.