Hierarchical self-assembly of organic prolate nanospheroids from hydrophobic rosette nanotubes

Supramolecular synthesis emerged recently as a new formalism to devise complex architectures held through noncovalent forces. Much of the research endeavor has been devoted to the use of H-bonds as the alphabet for chemical information encoding, and the structures expressed have spanned the range of dimensions and shapes, from discrete to infinite networks. Here we describe the synthesis and characterization of a GwedgeC base bearing two C12 alkyl chains, which undergoes a solvent-controlled multistep hierarchical self-assembly process into lamellar prolate nanospheroids. These assemblies were characterized by AFM, SEM, TEM, XRD, and SAXS, and a mechanism for their formation is proposed.     

On the quest for new mixed-metal mu-oxo-bridged complexes: synthesis of compounds containing transition metal-oxygen-main group metal motifs M-O-M1 (M = Ti, Zr; M1 = Al, Ga) without cyclopentadienyl ligands

The reaction of TiBz4 (Bz = benzyl) with LAlMe(OH), L = (2,6-iPr2C6H3NC(Me))2CH, afforded LAlMe(mu-O)TiBz3 (1) and [LAlMe(mu-O)]2TiBz2 (2), whereas the corresponding reaction with ZrBz4 resulted only in the formation of the trinuclear species [LAlMe(mu-O)]2ZrBz2 (3). The reaction of (Mes 2Ga(OH))2 x THF (Mes = 2,4,6-Me3C6H2) with Ti(NEt2)4 yielded the cluster compound TiGa6O7(NEt2)2(Mes)6 (4). All compounds have been characterized by elemental analysis, NMR spectroscopy, and mass spectrometry. Additionally, single crystal X-ray structure data of 1, 3, and 4 are reported. Compounds 1-4 show low catalytic activities in the polymerization of ethylene. Revisiting known mu-oxo-bridged complexes containing the M-O-M(1) (M = Ti, Zr, Hf; M(1) = Al, Ga) skeleton revealed that the application of polynuclear group 13 hydroxides and oxo bridged complexes possesses a potential for the preparation of new polyoxometal clusters.     

Error estimate in a finite volume approximation of the partial asymptotic domain decomposition

The method of asymptotic partial domain decomposition has been proposed for partial differential equations set in rod structures, depending on a small parameter. It reduces the dimension of the problem (or simplifies it in another way) in the main part of the domain keeping the initial formulation in the remaining part and prescribing the asymptotically precise conditions on the interface. This paper is devoted to the finite volume implementation of the method of asymptotic partial domain decomposition. We consider a model problem in a thin domain (its thickness is a small parameter). We obtain an error estimate, expressed in terms of the small parameter and the step of the mesh. Copyright © 2013 John Wiley & Sons, Ltd.     

Eigenvalues and eigenvectors assignment for neutral type systems

For a class of linear neutral type systems, the problem of eigenvalues and eigenvectors assignment is investigated, i.e. the system that has the given spectrum and almost all, in some sense, eigenvectors is investigated. The result is used for the analysis of the critical number of solvability of a vector moment problem.     

Triangulated Categories and the Ziegler Spectrum

The relationship between the Ziegler spectrum of (the category of modules over) a ring and the Ziegler spectrum of its derived category is investigated. Over von Neumann regular rings and hereditary rings the spectrum of the derived category is a disjoint union of copies of the spectrum of the ring but in general there are further indecomposable pure-injective objects of the derived category. Presented by A. Verschoren Mathematics Subject Classifications (2000) Primary: 18E30; secondary: 03C60.     

Highly functionalized pyranopyrazoles: synthesis,antimicrobial activity,simulation studies and their structure activity relationships (SARs)

Research on Chemical Intermediates - Development of potent antibacterial and antifungal agents is a permanently new and unremitting investigation in the therapeutic field. Still, medicinal research...     

Synthesis of diverse β-(nitrooxy)-substituted amines by regioselective ring-opening of aziridines under neat conditions

An efficient and regioselective method was developed for the synthesis of β-(nitrooxy)-substituted amine derivatives by ring-opening of different aziridines with Zn(NO₃)₂·6H₂O without using additives or catalyst. A library of β-(nitrooxy)-substituted amine derivatives having a variety of substituents has been synthesized. Excellent regioselectivity, high yields, clean reaction, ease of product isolation, easily accessible reactants, and solvent-free as well as environment friendly reaction conditions are the notable advantages of the present methodology. The nitrooxy derivative was successfully transformed into hydroxy derivative by simple reduction. Gram-scale synthesis demonstrates the potential applications of the present method.     

Disproportionation reaction of NO2/N2O4 with a Ru(II) porphyrin

A Ru(II) porphyrin rapidly reacts with NO2/N2O4 with the formation of a stable Ru(II) nitrosyl nitrato complex.     

Encapsulated reagents for nitrosation

[reaction: see text] A novel class of stable, mild, and size-shape-selective nitrosating agents for secondary amides is introduced. These are based on reversible entrapment and release of reactive nitrosonium species by calix[4]arenes. The NO(+) encapsulation controls the reaction selectivity.