Octanuclear heterometallic Fe-III-Ce-IV pivalate clusters: From a close {Fe4Ce4(mu(4)-O)(4)} cage to an open {Fe4Ce4(mu(4)-O)(2)(mu(3)-O)(2)} core

Ultrasonic irradiation of trinuclear [Fe3O(O2CCMe3)(6)(H2O)(3)]Me(3)CCO(2)2(Me3CCO2H) or hexanuclear [Fe6O2 (OH)(2)(O2CCMe3)(12)] pivalate precursors with Ce(NO3)(6)6H(2)O, NaN3 and triethanolamine (H3tea) in MeOH/ MeCN solution results in the synthesis of two new octanuclear Fe-III-Ce-IV clusters formulated as [Fe4Ce4O4 (O2CCMe3)(4)(tea)(4)(N-3)(4)(MeOH)(4)].MeOH (1) and [Fe4Ce4O4(O2CCMe3)(6)(tea)(4)(N-3)(2)(MeOH)(2)]center dot 3(MeOH) (2). The spectroscopic and thermal properties of these compounds corroborate oxidation states and formula. Single crystal X-ray diffraction analysis revealed that the metal atoms in clusters 1 and 2 are organized in unprecedented close {Fe4Ce4(mu(4)-O)(4)} and open {Fe4Ce4(mu(4)-O)(2)(mu(3)-O)(2)} cores, respectively. The topology of these cores has not been observed before in FeIII-CeIV chemistry

Formation and structural chemistry of the unusual cyanide-bridged dinuclear species [Ru-2(NN)(2)(CN)(7)](3-)(NN=2,2 '-bipyridine or 1,10-phenanthroline)

Crystallisation of simple cyanoruthenate complex anions [Ru(NN)(CN)(4)](2) (NN = 2,2'-bipyridine or 1,10-phenanthroline) in the presence of Lewis-acidic cations such as Ln(III) or guanidinium cations results, in addition to the expected [Ru(NN)(CN)(4)](2) salts, in the formation of small amounts of salts of the dinuclear species [Ru-2(NN)(2)(CN)(7)](3). These cyanide-bridged anions have arisen from the combination of two monomer units [Ru(NN)(CN)(4)](2) following the loss of one cyanide, presumably as HCN. The crystal structures of [Nd(H2O)(5.5)][Ru-2(bipy)(2)(CN)(7)] center dot 11H(2)O and [Pr(H2O)(6)][Ru-2(phen)(2)(CN)(7)] center dot 9H(2)O show that the cyanoruthenate anions form Ru-CN-Ln bridges to the Ln(III) cations, resulting in infinite coordination polymers consisting of fused Ru(2)Ln(2)(mu-CN)(4) squares and Ru(4)Ln(2)(mu-CN)(6) hexagons, which alternate to form a one-dimensional chain. In [CH6N3](3)[Ru-2(bipy)(2)(CN)(7)] center dot 2H(2)O in contrast the discrete complex anions are involved in an extensive network of hydrogen-bonding involving terminal cyanide ligands, water molecules, and guanidinium cations. In the [Ru-2(NN)(2)(CN)(7)](3) anions themselves the two NN ligands are approximately eclipsed, lying on the same side of the central Ru-CN-Ru axis, such that their peripheries are in close contact. Consequently, when NN = 4,4'-Bu-t(2)-2,2'-bipyridine the steric bulk of the t-butyl groups prevents the formation of the dinuclear anions, and the only product is the simple salt of the monomer, [CH6N3](2)[Ru((t)Bu(2)bipy)(CN)(4)] center dot 2H(2)O. We demonstrated by electrospray mass spectrometry that the dinuclear by-product [Ru-2(phen)(2)(CN)(7)](3) could be formed in significant amounts during the synthesis of monomeric [Ru(phen)(CN)(4)](2) if the reaction time was too long or the medium too acidic. In the solid state the luminescence properties of [Ru-2(bipy)(2)(CN)(7)](3) (as its guanidinium salt) are comparable to those of monomeric [Ru(bipy)(CN)(4)](2), with a (MLCT)-M-3 emission at 581 nm

Микромеханизмы деформации и разрушении слоистого материала из титанового сплава ВТ6 при ударном нагружении

The paper studies the phase composition, microstructure. and mechanisms of plastic deformation and fracture under shock loading in a layered material obtained by pressure welding of VT6 titanium alloy sheets. Under shock loading at 20 and 196 {5}C, the material is delaminated into sheet piles and this changes their fracture rate. At fracture surfaces, the initial crystal structure experiences structural phase decomposition resulting in dynamic rotations. In crystalline sublayers of the fracture surfaces and delamination, the material is fragmented. The effects are more pronounced at T =-196 °С

Получение и свойства керамических материалов на основе системы Al[2]O[3]-MgO

It is known that aluminum oxide is the most generally used ceramic material applied as structural, functional and biomaterial. Meanwhile, it is used not only in a high state and but also in a highporous state. To obtain the required functional properties it is alloyed by various oxides such as FeO, SiO[2], Y[2]O[3], MgO and others. What most interested us is the magnasium oxide (MgO), as it is well known that the MgO presence in the ceramics materials causes biological processes activation at the boundary "implant - bone". However, the introduction of MgO into sintered mixture may change technological regimes of ceramics production and as a result to the structure and properties of the material can be changed as well. The aim of this work is to study the influence of the concentration of the injected mixture into the sintered MgO in the amount up to 10 wt. %. onto porosity, shrinkage characteristics of the microstructure and mechanical properties of the sintered material

Heterometallic {Fe18M6} (M = Y, Gd, Dy) Pivalate Wheels Display Solvent-Induced Polymorphism

A new series of heterometallic wheels, isolated as [Fe18M6(piv)12(Htea)18(tea)6(N3)6]\ub7n(solvent) (MIII = Y (1a, 1b), Gd (2a, 2b), and Dy (3a, 3b); Hpiv = pivalic acid, H3tea = triethanolamine), forms by the reaction of trinuclear μ3-oxo-linked or hexanuclear μ-OH-linked Fe(III) pivalate clusters with rare earth nitrates, H3tea, and azide ligands in MeOH/MeCN or EtOH/MeCN media under ultrasonic irradiation. Single-crystal X-ray diffraction showed that wheels 1a-3a prepared from MeOH/MeCN solutions crystallize in the triclinic space group P1\uaf and have Ci symmetry, whereas wheels 1b-3b received from EtOH/MeCN solution crystallize in the trigonal space group R3\uaf and have C3i symmetry. Magnetic studies reveal medium antiferromagnetic exchange interactions within the Fe3 trimeric unit (with the exchange coupling parameters of JFe3 = -13.1 cm-1 for 1a, JFe3 = -11.6 cm-1 for 1b) and weak intermolecular antiferromagnetic exchange interactions (λmf = -0.366 mol cm-3 and -0.368 mol cm-3 (zJmf = -0.19 cm-1), respectively). This leads to spin ground states of S = 5/2 for each {Fe3} unit. Substitution of diamagnetic Y(III) centers by paramagnetic Ln(III) centers (in 2a/2b by Gd(III) and in 3a/3b by Dy(III) centers) results in ferromagnetic exchange interactions between the Fe(III) and Ln(III) centers in addition to the predominant antiferromagnetic Fe\ub7\ub7\ub7Fe interactions in 1a/1b

Revisited the modelling of underground gasifier system

У даній статті висвітлені основні аспекти впровадження якісно нових підходів щодо технологій термохімічного перетворення вуглецевмісної сировини, зокрема підземної газифікації вугілля. При трансформації зв’язку «гірничодобувне підприємство → комунальне господарство» з однією направленістю виробних процесів комунальне господарство також стає постачальником енергетичної сировини. При моделюванні системи підземного газогенератора раціональні принципи та допуски при їх побудові дають можливість встановити основні закономірності процесів, а також знехтувати другорядними факторами, що впливають на її формування. Закладення термодинамічних характеристик в нульмерну постановку задачі при моделюванні системи підземного газогенератора дозволяє кількісно спрогнозувати склад та властивості складних гетерогенних, багатоелементних, мультифазних систем в широкому діапазоні температур та тисків з урахуванням хімічних і фазових перетворень. Визначення функції зміни температури (T) від співвідношення дуттьової суміші та вихідної сировини (k m ) на основі проведення термодинамічного розрахунку в нульмерній постановці дозволяє обґрунтувати параметри розповсюдження теплового поля навколо підземного газогенератора як за довжиною вогневого вибою, так і за довжиною виймального стовпа.This article highlights the main aspects of the implementation of qualitatively new approaches to technologies of thermochemical conversion of carbon-containing raw materials during underground coal gasification. With the transformation of the connection “mining company → public utility company” with one direction of production processes, utilities also become a supplier of energy raw materials. When modeling an underground gasifier system, rational principles and tolerances in their construction make it possible to establish the basic patterns of processes, as well as to neglect the secondary factors influencing its formation. Establishing thermodynamic composition and properties of complex heterogeneous, multi-element, multiphase systems in a wide range of temperatures and pressures, considering chemical and phase transformations, can be predicted in several ways. Determining the function of temperature change (T) from the ratio of blast mixture and raw material (k m ) based on thermodynamic calculation in zero-dimensional formulation allows to substantiate the parameters of thermal field propagation around the underground gasifier by the length of the combustion face and the length of the extraction column