Synthesis and characterization of nanoparticles with an iron oxide magnetic core and a biologically active trialkylsilylated aliphatic alkanolamine shell

Water-soluble double-coated magnetic nanoparticles (NPs) containing cytotoxic decyldimethyl(β$\beta$-dimethylaminoethoxy)silane methiodide (AA) molecule sorbed at biocompatible magnetic particles, which consist of magnetite pre-coated with oleic acid (OA), have been prepared. X-ray line profile broadening analysis was used for crystallite size determination. The method of magnetogranulometry has been used for determination of diameter of iron oxide magnetic core and magnetic properties of NPs prepared. In vitro cytotoxicity on monolayer tumor cell lines HT-1080 (human fibrosarcoma), MG-22A (mouse hepatoma) and normal mouse fibroblasts (NIH 3T3) has been studied. It was revealed that all the water-based colloidal solutions obtained are non-toxic and possess high NO-induction ability.     

Frustrated Lewis Pairs Comprising Nitrogen Lewis Acids for Si–H Bond Activation

N-heterocyclic nitrogen Lewis acids are a recent addition to the field of organic chemistry. Based on nitrenium cations, these acids where previously shown to generate Lewis adducts when combined with the appropriate Lewis bases. Herein, a triazinium-based Lewis acid was combined with tBu₃P to generate a frustrated Lewis pair (FLP) capable of cleaving, for the first time, Si−H bonds in silanes. Whereas low yields were initially encountered owing to insufficient Lewis acidity, a new nitrenium-based Lewis acid was synthesized, and its superior Lewis acidity was experimentally and computationally confirmed. A FLP based on this acid cleaved the Si−H bond in PhSiH₃, generating the triazane product in a quantitative yield. This unprecedented N−H triazane was fully characterized by multinuclear NMR techniques and single-crystal X-ray crystallography. A new class of compounds, N-H triazanes display the potential capacity to participate in hydride transfer reactions.     

Synthesis of new-type 1,3,6-triazocine via intramolecular reactions of iodocyclization and [3+2] azido cycloaddition

Selective iodocyclization of 6-(alkenylamino)-1-allylpyrazolo[3,4-d]pyrimidines provided hydrogenated derivatives of 1-allyl-8(9)-iodomethylimidazo(pyrimido)[1,2-a]pyrazolo[4,3-e]pyrimidines which were further reacted with NaN₃ at 75°С to 80°С to give a series of new-type 1,3,6-triazocines annulated with the pyrazole, pyrimidine, imidazole (or pyrimidine), and 1,2,3-triazole rings. The compounds synthesized were structurally characterized by analytical, spectral (IR, ¹H and ¹³C NMR, HPLC-mass), and X-ray diffraction data.     

Assembly of Tetrazolylfuroxan Organic Salts: Multipurpose Green Energetic Materials with High Enthalpies of Formation and Excellent Detonation Performance

A series of highly energetic organic salts comprising a tetrazolylfuroxan anion, explosophoric azido or azo functionalities, and nitrogen-rich cations were synthesized by simple, efficient, and scalable chemical routes. These energetic materials were fully characterized by IR and multinuclear NMR (¹H, ¹³C, ¹⁴N, ¹⁵N) spectroscopy, elemental analysis, and differential scanning calorimetry (DSC). Additionally, the structure of an energetic salt consisting of an azidotetrazolylfuroxan anion and a 3,6,7-triamino-7H-[1,2,4]triazolo[4,3-b][1,2,4]triazolium cation was confirmed by single-crystal X-ray diffraction. The synthesized compounds exhibit good experimental densities (1.57–1.71 g cm⁻³), very high enthalpies of formation (818–1363 kJ mol⁻¹), and, as a result, excellent detonation performance (detonation velocities 7.54–8.26 kms⁻¹ and detonation pressures 23.4–29.3 GPa). Most of the synthesized energetic salts have moderate sensitivity toward impact and friction, which makes them promising candidates for a variety of energetic applications. At the same time, three compounds have impact sensitivity on the primary explosives level (1.5–2.7 J). These results along with high detonation parameters and high nitrogen contents (66.0–70.2 %) indicate that these three compounds may serve as potential environmentally friendly alternatives to lead-based primary explosives.     

Quasi-SMILES: quantitative structure–activity relationships to predict anticancer activity

Molecular Diversity - Reliable prediction of anticancer potential of different substances for different cells using unambiguous algorithms is attractive alternative of experimental investigation of...     

Snapshot location for POD in control of a linear heat equation

In the present work, we study the approximation of a distributed optimal control problem for a linear heat equation with model order reduction based on Proper Orthogonal Decomposition (POD-MOR). We show that snapshot location for control problems is crucial in model reduction. For the determination of the time instances (snapshot locations) we utilize an a-posteriori error control concept which is based on a reformulation of the optimality system of the underlying optimal control problem as a second order in time and fourth order in space elliptic system. Finally, we present a numerical test to illustrate our approach. (© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Lost heat capacity and entropy in the helical magnet MnSi

The heat capacity of MnSi at B = 0 and B = 4 T was measured in the temperature range 2.5-100 K. To analyze the data, calculations of the phonon spectrum and phonon density of states in MnSi were performed. The calculated phonon frequencies were confirmed by means of inelastic neutron scattering. The analysis of the data suggests the existence of negative contributions to the heat capacity and entropy of MnSi at T > T(c) that may imply a specific ordering in the spin subsystem in the paramagnetic phase of MnSi.     

Secondary Metabolites,including a New 5,6-Dihydropyran-2-One,Produced by the Fungus Diplodia corticola. Aphicidal Activity of the Main Metabolite,Sphaeropsidin A

An undescribed 5,6-dihydropyran-2-one, namely diplopyrone C, was isolated and characterized from the cultures of an isolate of the fungus Diplodia corticola recovered from Quercus suber in Algeria. The structure and relative stereostructure of (5S,6S,7Z,9S,10S)-5-hydroxy-6-(2-(3-methyloxiran-2-yl)vinyl)-5,6-dihydro-2H-pyran-2-one were assigned essentially based on NMR and MS data. Furthermore, ten known compounds were isolated and identified in the same cultures. The most abundant product, the tetracyclic pimarane diterpene sphaeropsidin A, was tested for insecticidal effects against the model sucking aphid, Acyrthosiphon pisum. Results showed a toxic dose-dependent oral activity of sphaeropsidin A, with an LC₅₀ of 9.64 mM.