Formation of silver nanoparticles on shells of polyelectrolyte capsules using silver-mirror reaction

Polymer capsules prepared by the successive adsorption of oppositely charged polyelectrolytes are modified by silver nanoparticles using the silver-mirror reaction. Substantial differences in the structure of nanocomposite polyelectrolyte shells of capsules formed on cores composed of polystyrene and CaCO₃ are revealed by atomic force microscopy and transmission electron microscopy. The effect of the conditions of silver-mirror reaction (time and temperature) on the amount, size, and the distribution of silver nanoparticles over the capsule surface is studied. It is shown by small-angle X-ray scattering that, upon the formation of nanocomposite capsule shell on calcium carbonate microspherulites, the size of silver nanoparticles is limited primarily by the pore sizes of CaCO₃ cores.     

Synthesis of pyrazolo[1,3,2]diazaphosphinin‐4‐ones

It was found that phosphinimidic isocyanates based on 3‐, 4‐, and 5‐aminopyrazoles could undergo intramolecular heterocyclization to yield previously unknown pyrazolo[1,3,2]diazaphosphorin‐4‐ones containing an endocyclic PN double bond. It was shown that phosphinimidic isocyanate based on 4‐aminopyrazole, in which there are two positions (3 and 5) available for the cyclization, reacts exclusively at the 5‐carbon atom. © 2012 Wiley Periodicals, Inc. Heteroatom Chem 23:210–215, 2012; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.21005     

Elastic domains in antiferromagnets on substrates

We consider periodic domain structures which appear due to the magnetoelastic interaction if the antiferromagnetic crystal is attached to an elastic substrate. The peculiar behavior of such structures in an external magnetic field is discussed. In particular, we find the magnetic field dependence of the equilibrium period and the concentrations of different domains.     

Intramolecular cyclization of N‐hetarylphosphinimidic isocyanates in the synthesis of 1,7‐dihydro‐4H‐imidazo[4,5‐d][1,3,2]diazaphosphinin‐4‐one (2‐phosphapurine)

It has been found that N‐(4‐imidazolyl)phosphinimidic isocyanates obtained by the reaction of the corresponding chlorophosphine N‐hetarylimide with alkali metal cyanates can undergo intramolecular heterocyclization to yield previously unknown phosphapurine derivatives containing an endocyclic PN double bond. This radically novel approach to building the 2‐phosphapurine system shows promise for the synthesis of related phosphorus‐containing fused heterocycles. © 2010 Wiley Periodicals, Inc. Heteroatom Chem 21:453–455, 2010; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.20617     

4‐Phosphorylated 1,2‐disubstituted imidazoles

4‐Selenophosphoryl‐1,2‐disubstituted imidazoles have been obtained by thermal decomposition of methyl 5‐(diamidoselenophosphoryl)imidazolium chlorides. The position of selenophosphoryl group in the imidazole ring was proved by ¹H, ¹³C NMR spectroscopy, and X‐ray analysis. Previously unknown diamido‐ and dichloro(imidazol‐4‐yl)‐ phosphonites were synthesized, and differences in their reactivity compared to analogous 5‐phosphorylated imidazoles are shown. © 2010 Wiley Periodicals, Inc. Heteroatom Chem 21:103–118, 2010; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20584     

Hybrid discrete-continuous systems: I. stability and stabilizability

For hybrid discrete-continuous linear stationary systems, we consider the basic problems of qualitative control theory, namely, stability and stabilization. For such systems, we obtain parametric criteria for asymptotic and exponential stability ensuring a prescribed stability exponent and a rank criterion for stabilizability. We consider the problem of finding the minimum number of inputs for which the considered system is stabilizable. We suggest an effective algorithm for constructing the matrix describing the structure of the input device of a minimum-input stabilizable system. An example illustrating the results is given.     

Ir(111) surface state with giant Rashba splitting persists under graphene in air

We reveal a giant Rashba effect (α(R)≈1.3 eV??) on a surface state of Ir(111) by angle-resolved photoemission and by density functional theory. It is demonstrated that the existence of the surface state, its spin polarization, and the size of its Rashba-type spin-orbit splitting remain unaffected when Ir is covered with graphene. The graphene protection is, in turn, sufficient for the spin-split surface state to survive in ambient atmosphere. We discuss this result along with indications for a topological protection of the surface state.     

On wetting transition in superconductivity

The existence of two solutions for proximity-induced superconductivity described by the Ginzburg-Landau theory is established in the general case. A first-order phase transition can occur between these states, resulting in superconductive wetting.