Palladium catalyzed cross‐methylation of bromoheterocycles with intramolecularly stabilized dimethyl indium reagents

Although the intramolecularly stabilized [(3‐dimethylamino)propyl]dimethylaluminum ( 1a ) fails to undergo palladium‐catalyzed cross‐coupling with bromopyridines and with bromofuran derivatives, the analogous gallium and indium reagent 1b and 1c smoothly cross‐methylate these and other bromoheterocycles. The cross‐coupling can be performed also with the dimeric indium and gallium compounds bis(μ‐[2‐(dimethylamino)ethanolato‐N,O:O]tetramethyldigallium and ‐diindium ( 2b and 2c , respectively). The indium reagent is fairly air‐stable and the reactions can be carried out under ambient conditions. The yields are generally very high but are influenced by steric and electronic effects.     

Strongly non-local modelling of dislocation transport and pile-up

The purpose of this work is the continuum modelling of transport and pile-up of infinite discrete dislocation walls driven by non-local interaction and external loading. To this end, the underlying model for dislocation wall interaction is based on the non-singular Peierls–Nabarro (PN) model for the dislocation stress field. For simplicity, attention is restricted to walls consisting of single-sign dislocations and to continuous wall distributions on a single glide plane. In this context, the influence of strongly non-local (SNL; long-range) interaction, and its approximation as weakly non-local (WNL; short-range) are studied in the context of interaction- and external-load-driven wall pile-up at a boundary. The pile-up boundary is modelled via a spatially dependent dislocation mobility which decreases to zero at the boundary. The pile-up behaviour predicted by the current SNL-based continuous wall distribution modelling is consistent with that predicted by discrete wall distribution modelling. Both deviate substantially from the pile-up behaviour predicted by WNL-based continuous wall distribution modelling. As such, it is clearly essential to account in continuum models for the intrinsic SNL character of the interaction between same-sign dislocations ‘close’ to the boundary. Gradient-based WNL ‘approximation’ of this interaction is not justified.     

Solvent-free,sonochemical, one-pot,four-component synthesis of 2H-indazolo[2,1-b]phthalazine-triones and 1H-pyrazolo[1,2-b]phthalazine-diones catalyzed by Fe3O4@SiO2-imid-PMAn magnetic nanoparticles

Research on Chemical Intermediates - A practical and green method for the synthesis of 2H-indazolo[2,1-b]phthalazine-triones and 1H-pyrazolo[1,2-b]phthalazine-diones using Fe3O4@SiO2-imid-PMAn...     

Asymptotic representations of solutions of one class of second-order ordinary differential equations

We establish asymptotic representations for some classes of solutions of nonautonomous second-order differential equations close, in a certain sense, to linear equations.     

Surface plasmon spectroscopy of gold-poly-N-isopropylacrylamide core-shell particles

Highly uniform, core-shell microgels consisting of single gold nanoparticle cores and cross-linked poly-N-isopropylacrylamide (PNIPAM) shells were prepared by a novel, versatile protocol. The synthetic pathway allows control over the polymer shell thickness and its swelling behavior. The core-shell structure was investigated by electron microscopy and atomic force microscopy, whereas the swelling behavior of the shell was studied by means of dynamic light scattering and UV-vis spectroscopy. Furthermore, the latter method was used to investigate the optical properties of the hybrid particles. By modeling the scattering contribution from the PNIPAM shells, the absorption spectra of the gold nanoparticle cores could be recovered. This allows the particle concentration to be determined, and this in turn permits the calculation of the molar mass of the hybrid particles as well as the refractive index of the shells.     

Facile synthesis of metal-organic framework films via in situ seeding of nanoparticles

A facile in situ nanoparticle seeding method is reported to prepare MIL-101(Cr) films on alumina supports. The in situ seeding of MIL-101(Cr) nanoparticles was promoted by use of dimethylacetamide (DMA). The generality of this approach is further demonstrated for Cu(3)(btc)(2) films by using a (poly)acrylate promoter.     

Sonochemical synthesis of Dy2(CO3)3 nanoparticles,Dy(OH)3 nanotubes and their conversion to Dy2O3 nanoparticles

Dysprosium carbonates nanoparticles were synthesized by the reaction of dysprosium acetate and NaHCO₃ by a sonochemical method. Dysprosium oxide nanoparticles with average size about 17 nm were prepared from calcination of Dy₂(CO₃)₃·1.7H₂O nanoparticles. Dy(OH)₃ nanotubes were synthesized by sonication of Dy(OAC)₃·6H₂O and N₂H₄. The as-synthesized nanostructures were characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRD), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FT-IR). Photoluminescence measurement shows that the nanoparticles have two emission peaks around 17,540 cm^?1 and 20,700 cm^?1, which should come from the electron transition from ⁴F_9/2 → ⁶H_15/2 levels and ⁴F_9/2 → ⁶H_13/2 levels, respectively. The effect of calcination temperature and sonication time was investigated on the morphology and particle size of the products. The sizes could be controlled by the feeding rate of the precipitating agent (NaHCO₃ and N₂H₄) and slower feeding rate lead to smaller nanoparticles.     

Guiding Drugs to Target‐Harboring Organelles: Stretching Drug‐Delivery to a Higher Level of Resolution

The ratio between the dose of drug required for optimal efficacy and the dose that causes toxicity is referred to as the therapeutic window. This ratio can be increased by directing the drug to the diseased tissue or pathogenic cell. For drugs targeting fungi and malignant cells, the therapeutic window can be further improved by increasing the resolution of drug delivery to the specific organelle that harbors the drug's target. Organelle targeting is challenging and is, therefore, an under‐exploited strategy. Here we provide an overview of recent advances in control of the subcellular distribution of small molecules with the focus on chemical modifications. Highlighted are recent examples of active and passive organelle‐specific targeting by incorporation of organelle‐directing molecular determinants or by chemical modifications of the pharmacophore. The outstanding potential that lies in the development of organelle‐specific drugs is becoming increasingly apparent.