The Crystal Structure of Pyridinium μ-salicylato-tetrachloro-μ- oxo-μ-ethoxo-dioxodimolibdate(V)

The crystal structure of the title complex has been determined from diffractometer X-ray intensity data by means of Patterson · and Fourier methods and refined by the full matrix least-squares technique to an R index of 0.060 (Rw = 0.064). The crystals are built up of pyH+ cations and [Mo20sCl4 (C2HsO) (HOC6H4C02)J2- anions. Each molybdenum atom of the binuclear anion is octahedrally coordinated, being bonded to two oxo-oxygen atoms, one terminal (1.669 and 1.670 A) and one bridging (1.908 and 1.916 A), one bridging ethoxo-oxygen atom (1.963 and 1.964 A), one salicylato- oxygen atom (2.295 and 2.317 A) and two chlorine atoms (from 2.399 to 2.432 A). The terminal oxo-oxygens occupy a cis- position with respect to the Mo20 2 bridge. The dihedral angle between the two Mo02 planes within the bridge amounts to 164.9°. The Mo-Mo bond lengths is 2.646A

The Crystal Structure of Pyridinium μ-salicylato-tetrachloro-μ- oxo-μ-ethoxo-dioxodimolibdate(V)

The crystal structure of the title complex has been determined from diffractometer X-ray intensity data by means of Patterson · and Fourier methods and refined by the full matrix least-squares technique to an R index of 0.060 (Rw = 0.064). The crystals are built up of pyH+ cations and [Mo20sCl4 (C2HsO) (HOC6H4C02)J2- anions. Each molybdenum atom of the binuclear anion is octahedrally coordinated, being bonded to two oxo-oxygen atoms, one terminal (1.669 and 1.670 A) and one bridging (1.908 and 1.916 A), one bridging ethoxo-oxygen atom (1.963 and 1.964 A), one salicylato- oxygen atom (2.295 and 2.317 A) and two chlorine atoms (from 2.399 to 2.432 A). The terminal oxo-oxygens occupy a cis- position with respect to the Mo20 2 bridge. The dihedral angle between the two Mo02 planes within the bridge amounts to 164.9°. The Mo-Mo bond lengths is 2.646A

Mechanochemical synthesis of calcium oxalate

Ova studija prikazuje mehanokemijsku sintezu kalcijeva oksalata u planetarnom kugličnom mlinu, bez i uz prisutnost otapala. Dosadašnja istraživanja su uglavnom bila usmjerena na otopinsku sintezu kalcijeva oksalata. U ovom radu opisujemo drugačiji pristup, koji će donijeti nova saznanja o sintezi kristala kalcijeva oksalata, a koje su uzrokovane utjecajem mehaničke energije. Cilj istraživanja je sinteza, identifikacija i karakterizacija pojedine oksalatne hidratne faze sintetizirane iz kalcijevih soli (klorida, nitrata i sulfata). Ispitivan je utjecaj brzine mljevenja i praćena je reakcija u ovisnosti o vremenu sinteze. Strukturalna i termička svojstva uzoraka ispitana su FTIR spektroskopijom i termogravimetrijskom analizom (TGA). Morfološke karakteristike kalcijeva oksalata te raspodjela veličine čestica određene su optičkom mikroskopijom i dinamičkim raspršenjem svjetlosti (DLS)

Synthesis and Anti-inflammatory Activity of Novel Furochromenes

A series of variously substituted furochromenes, hemiacetals 2, acetals 3, and rearranged compounds 4, were synthesized from variously substituted 4-hydroxycoumarins and evaluated in several in vitro assays, inhibition of mast cell degranulation induced by the activation of Fcε receptor type I or calci-um ionophore and leukotriene B4 (LTB4) inhibition. The most active derivatives, 3p and 4p (8-iso-propyl substitution in coumarin ring) and 3r (5-methyl-8-chloro substitution), showed significant inhibition of mast cell degranulation (Fctriggered) and LTB4, and exhibited significant local anti-inflammatory activity in PMA induced ear edema in CD1 mice, with potency equal (compounds 3p and 4p) or better (compound 3r) in comparison with zileuton, a reference drug used. It might be a promising direction for developing novel drugs as potential agents for the treatment of allergies and other inflammatory diseases.(doi: 10.5562/cca2240

Sol-Gel Synthesis of Ceria-Zirconia-Based High-Entropy Oxides as High-Promotion Catalysts for the Synthesis of 1,2-Diketones from Aldehyde

Efficient Lewis-acid-catalyzed direct conversion of aldehydes to 1,2-diketones in the liquid phase was enabled by using newly designed and developed ceria–zirconia-based high-entropy oxides (HEOs) as the actual catalysts. The synergistic effect of various cations incorporated in the same oxide structure (framework) was partially responsible for the efficiency of multicationic materials compared to the corresponding single-cation oxide forms. Furthermore, a clear, linear relationship between the Lewis acidity and the catalytic activity of the HEOs was observed. Due to the developed strategy, exclusively diketone-selective, recyclable, versatile heterogeneous catalytic transformation of aldehydes can be realized under mild reaction conditions

Influence of the size and type of pores on brick resistance to freeze-thaw cycles

This paper estimates the frost resistance of bricks using the ratio of compressive strength before freezing to compressive strength after freezing to describe the damage degree of bricks being exposed to freeze-thaw cycles. In an effort to find the ratio that clearly distinguishes resistant bricks from non-resistant bricks, the authors attempted to establish the correlation between the ratio and Maage factor as a recognized model for assessing brick resistance. To clarify the degree of damage of individual bricks, the pore size distribution has been investigated by means of mercury porosimetry. Additionally, micro computed X-ray tomography (micro-CT) has been employed to define the influence of the type of pores (open or closed) and their connectivity on the frost resistance of bricks. According to the results, it can be concluded that there is a good correlation between the Maage factor and the ratio of pre- to post-freeze-thaw cycle compressive strengths, and that the latter ratio strongly correlates with the percentage of large pores (≥3 mm) in the brick. If such a correlation could be confirmed in a larger sample, then the ratio of pre- to post-freeze-thaw cycle compressive strengths could be used as a new method for assessing brick resistance to freeze-thaw cycles and it would be possible to determine the minimum percentage of large pores required to ensure the overall resistance of brick to freeze-thaw conditions. The complexity of the problem is, however, evidenced by the fact that no clear connection between the type (open versus closed) or connectivity of pores and the frost resistance of bricks could be revealed by micro-CT

Electrocatalysis of fuel cells reaction on Pt and Pt-bimetallic anode catalysts: A selective review

In this review we selectively summarize recent progress, primarily from our laboratory, in the development of interrelationships between the kinetics of the fuel cells reactions and the structure/composition of anode catalysts. The focus is placed on two types of metallic surfaces: platinum single crystals and bimetallic surfaces based on Pt. In the first part it was illustrated that the hydcogen reaction is structure sensitive process, with Pt(110) being an order of magnitude more active than either of the atomically "flatter" (100) and (111) surfaces. The hydrogen reaction on Pt(hkl) modified by pseudomorphic Pd (sub)monolayers shows the "volcano-like" behavior, having the maximum rate on Pt(111) modified by 1 ML of Pd. The Pt(111)-Pd system is used to demonstrate how the energetics of intermediates formed in the hydrogen reaction is affected by interfacial bonding and energetic constraints produced between pseudomorphic Pd films and the Pt(111) substrate. In the second part it was shown that the oxidation of Ha in the presence of CO occurs concurrently with CO oxidation on Pt and Pt bimetallic surfaces. The Pt-Ru system is used to demonstrate that both the bifunctional effect and the ligand effect contribute to the influence of Ru on the CO oxidation rate and for Hz oxidation process in the presence of CO. The knowledge is then used to create the real-life catalyst with the catalytic activities which are, to the greatest extend possible similar to the tailor-made surface

Feasibility of Agricultural Biomass Fly Ash Usage for Soil Stabilisation of Road Works

Agricultural biomass ash is a waste material produced by incineration of residue from fields after harvesting crops. The use of agricultural biomass in industry produces large quantities of ash that represent an ecological problem. Another ecological problem is the dependency of road building on natural materials, which has been traditionally used for all pavement layers. Today, roads are built on less accessible and suitable terrains, increasing the need for improving the mechanical characteristics of locally available materials by various means of stabilisation. Within this research, three agricultural biomass fly ashes are used as lime substitutes for hydraulically stabilised soil. The purpose of this research is evaluation of potential use of agricultural biomass fly ash for the soil stabilisation of road works, i.e., for embankment and subgrade purposes. The results indicate that there is a potential of using barley, sunflower seed shells and wheat fly ash as lime substitutes in the soil stabilisation of road works. The strength characteristics of stabilised soil incorporating biomass fly ash are highly dependent on its chemical composition. Using a three-dimensional digital image correlation technique, it is concluded that the elastic properties of stabilised soil correlate to a fracture mechanism that can be efficiently defined by this modern research tool

Special-Purpose River-Port Sediment Valorization as Road Construction Material Emphasising Environmental Aspects

Special-purpose river port sediment was investigated for its potential use as a road construction material. Sediment samples were extracted from three locations in three small river ports, and detailed laboratory research was conducted to determine its basic mechanical properties and characteristics that can potentially have an adverse influence in a roadside environment. The results of the research conducted indicate that there is a need for systematic monitoring of the quality and quantity of sediment in special-purpose river ports of the Danube River Basin to maintain its mobility and prevent flooding. The basic engineering characteristics (Proctor elements, Atterberg limits, California bearing ratio, and unconfined compressive strength) determined represent the good potential of the sediment samples tested herein for use in road construction. In addition, the chemical characteristics tested indicate the need for detailed analyses of the potential environmental risk before application in civil engineering structure