Copper ion mediated selective cleavage of C-S bond in ferrocenylthiosemicarbazone forming mixed geometrical [(PPh3)Cu(μ-S)2Cu(PPh3)2] having Cu2S2 core: toward a new avenue in copper-sulfur chemistry

Unprecedented selective cleavage of the carbon-sulfur bond of the ferrocenylthiosemicarbazone moiety has been observed for the first time, resulting in the formation of mixed geometrical binuclear copper complex [(PPh(3))Cu(μ-S)(2)Cu(PPh(3))(2)]. Upon trying direct synthesis of the title complex, an unusual tetranuclear [Cu(4)(μ(3)-Cl)(4)(PPh(3))(4)] cubane resulted.     

Diversifying the structural architecture of synthetic oligomers: the hetero foldamer approach

Conformationally ordered synthetic oligomers, also called "foldamers", have attracted considerable attention in recent years owing to their ability to mimic the structural architecture of biopolymers and also because of their potential applications in biomedical and material science fields. Until recently, the major focus in this area has been the development of oligomers featuring a single type of monomer building blocks. However, due to the enormous possibility of augmenting the conformational space available for oligomer design, the hetero foldamer approach has been introduced very recently. This feature article aims to describe foldamers with unique structural architectures, exclusively featuring heterogeneous backbones (hetero foldamers).     

Preparation, spectroscopy, EXAFS, electrochemistry and pharmacology of new ruthenium(II) carbonyl complexes containing ferrocenylthiosemicarbazone and triphenylphosphine/arsine

A new series of new hetero-bimetallic complexes containing iron and ruthenium of the general formula [RuCl(CO)(B)(EPh3)(L)] (where E=P or As; B=PPh3, AsPh3, py or pip; L=ferrocene derived monobasic bidentate thiosemicarbazone ligand) have been synthesized by the reaction between ferrocene-derived thiosemicarbazones and ruthenium(II) complexes of the type [RuHCl(CO)(B)(EPh3)2] (where E=P or As; B=PPh3, AsPh3, py or pip). The new complexes have been characterized by elemental analyses, IR, electronic, NMR (1H, 13C and 31P), EXAFS (extended X-ray absorption fine structure spectroscopy) and cyclic voltammetric techniques. Antibacterial activity of the new complexes has been screened against Escherichia coli, Vibrio cholerae, and Pseudomonas aeruginosa species.     

Enantiopure Polyradical Tetrahedral Pd12L6 Cages

The synthesis of cages with a polyradical framework remains a challenging task. Herein is reported an enantiomeric pair of quinoid-bridged polyradical tetrahedral palladium(II) cages that are stabilized by an unusual dianionic diradical form (dhbq^..2−). These cages have been characterized by electron paramagnetic resonance and UV-visible spectroscopy, squid magnetometry and mass spectrometry. Single-crystal-derived X-ray investigations of the iso-structural cages built on fluoranilate linkers confirm the tetrahedral structure of the obtained radical cages. Theoretical calculations showed that the diradical state of the dhbq anions is more stable than the usual monoradical state. A weak ferromagnetic exchange between adjacent radical centers was observed in DFT studies.     

Fluid flow and thermal analysis of a circular journal bearing

In this paper, three dimensional momentum and continuity equations and three dimensional energy equations are solved simultaneously to obtain pressure, velocity and temperature field in the fluid of a hydrodynamic circular journal bearing. Solutions of these equations are obtained by using the powerful numerical technique, finite element method. For a range of values of eccentricity ratios, the static performance characteristics in terms of the load capacity, attitude angle, end leakage and the power loss are computed and the results are presented.

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Untersuchung des Strömungs- und Temperaturverhaltens eines Wellenlagers

Zusammenfassung In der Arbeit werden die dreidimensionalen Impuls-, Kontinuitäts- und Energiegleichungen gleichzeitig gelöst, um die Druck-, Geschwindigkeits- und Temperaturverteilung im Fluid eines hydrodynamischen Wellenlagers zu erhalten. Die Lösung wird mit Hilfe des wirksamen Werkzeugs der Finiten Elemente gewonnen. Für einen gewissen Bereich des Exzentrizitätsverhältnisses sind die statischen Betriebscharakteristiken als Funktion der Belastung, des Anstiegswinkels, der Leckage und des Reibungsdruckverlustes berechnet und dargestellt worden.

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Ru/Al2O3-catalyzed transfer dehydrogenation of alcohols

Summary Primary and secondary alcohols were oxidized to their corresponding aldehydes or ketones in good yields using Ru/Al₂O₃ as catalyst in the presence of acetone. The catalyst can be recovered by simple filtration and reused after washing with acetone.     

Dynamic response of composite plates with cut-outs,part II: Clamped-clamped plates

The forced and free dynamic response of plates with cut-outs formulated in Part I [1] is used to investigate the effect of cut-outs on the natural frequencies of clamped-clamped plates. The size, shape and location of the cut-out is expressed as a displacement dependent external loading. The plates considered are homogeneous and anisotropic. Lagrange's equations of motion lead to an infinite system of differential equations in time-dependent generalized co-ordinates with generalized forces which include the effects of the cut-outs. There is an infinite system of frequency equations for free vibrations. The infinite system is truncated to a finite system of equations depending upon the accuracy desired in frequency values. Results are given for square, clamped-clamped plates with centrally located square cut-outs for different modulus ratios. Good agreement is obtained when results for isotropic plates with cut-outs are compared with available theoretical and experimental results.