Ribbed-monofunctionalized iron(II) clathrochelate with tert-butyl sulfide substituents: Synthesis,structure, and thermochemical transformations

A ribbed-monofunctionalized macrobicyclic iron(II) complex with tert-butyl sulfide substituents has been prepared via nucleophilic substitution of its dichloroclathrochelate precursor with tert-butylthiolate ion. This new complex has been characterized using elemental analysis, IR and multinuclear NMR spectroscopy, and the single crystal X-ray diffraction. Its thermal destruction occurs with release of isobutylene and polyunsaturated hydrocarbons giving iron borate, iron fluoropolyborate, and iron nitride as follows from combined thermal analysis and X-ray powder diffraction data.     

Photochromism of 6′-cyanosubstituted spirooxazines in frozen alcohol matrices

For three 6′-cyanosubstituted spironaphthooxazines, spectral characteristics of an open form and quantum yields of photoisomerization were determined both at room temperature and in frozen alcohol matrices. Spironaphthooxazines have demonstrated fairly high (0.01–0.02) quantum yields of open form appearance at 77 K. The observed peculiarities of the open form UV spectra were explained by the temperature dependence of the open form isomers distribution. Partial stabilization of the nonequilibrium isomers of an open form in the low-temperature matrices was revealed.     

Free-radical reactions of the tris-dioximate clathrochelates: synthesis and X-ray structure of the first cyclohexyl-substituted monoribbed-functionalized macrobicyclic iron(ii) complex

Quantum chemical calculations were performed at the DFT level for the boron-capped dichloro-substituted tris-dioximate iron(II) clathrochelate and cyclohexane and 1,4-dioxane radicals. The 1,4-dioxane and cyclohexane radicals are nucleophiles towards the macrobicyclic precursor studied. The reaction of this clathrochelate with cyclohexane in the presence of a free-radical initiator resulted in substitution of a chlorine atom by a cyclohexyl fragment. The compound obtained was characterized by elemental analysis, IR spectroscopy, ¹H and ¹³C{¹H} NMR, and single-crystal X-ray diffraction data.     

High pressure solid state amorphization of Si,Ge and solid solutions Si:GaAs,Ge:GaSb

Abstract

The bulk amorphous tetrahedral semiconductors (Si, Ge. Si_0.89(GaAs)_0.11, Ge_1?x(GaSb)_x (0.12<X<I)) were obtained using solid state amorphization. The disordering process occurs at the decompression of high pressure phases Si II, Gell at low temperatures and of solid solutions Sill: GaAs, GeII: GaSb at room temperature. The structure and stability of the obtained phases were investigated     

Nonmetal-metal transitions in liquid substances under high pressure

Abstract

In the melts of Te, Se, S, I₂ and Mg₃Bi₂ the nonmetal-metal transitions were found under pressure. The transitions are accompanied by a decrease of the volume. The transitions seem to terminate at high temperature by “critical regions”. For S and Se the kinetics of the transitions and the pressure influence on the solidification of the melts were investigated.

The existence of the transitions of this kind gives an explanation of anomalies of melting curves of some substances.     

First hybrid oximehydrazonate phthalocyaninoclathrochelates: The synthesis and properties of lutetium phthalocyanine-capped cage iron(II) complexes

Ditopic oximehydrazonate iron(II) phthalocyaninoclathrochelates were synthesized by a transmetallation (a capping group exchange) reaction of the initial labile triethylantimony-capped clathrochelate iron(II) oximehydrazonates with lutetium(III) phthalocyanine as a Lewis acid. The complexes obtained were characterized using elemental analysis, PD and MALDI-TOF mass spectrometries, IR, UV–Vis, ⁵⁷Fe Mössbauer, and ¹H, ¹³C{¹H} NMR spectroscopies. An encapsulated iron(II) ion was found to be in a low-spin state. The cyclic voltammograms show oxidation and reduction waves assignable to Fe^2+/3+ couples of macrobicyclic framework and to phthalocyanine macrocycles.