Transition-metal nanoparticles in imidazolium ionic liquids: recyclable catalysts for biphasic hydrogenation reactions

1-n-Butyl-3-methylimidazolium hexafluorophosphate room-temperature ionic liquid is not only suitable as a medium for the preparation and stabilization of iridium nanoparticles but also ideal for the generation of recyclable biphasic catalytic systems for hydrogenation reactions. Thus, Ir(0) nanoparticles with a mean diameter of 2 nm have been prepared by reduction of Ir(I) dissolved in the ionic liquid with H2. This catalytic solution can be reused several times for the biphasic hydrogenation of olefins under mild reaction conditions.     

Distribution of film orientations in free and strained foams

We show that the distribution of film orientations in a free (i.e., unstrained) foam cluster, though in general not uniform, has the same second moments as a uniform distribution. This is, however, in general not true of its other moments, which reflects the internal order of film orientations imposed by Plateau's laws. For a strained cluster, we relate the deviations of the second moments of the orientation distribution from their values for an unstrained cluster, to the stresses acting on the cluster. Our predictions are corroborated by experimental results for free and strained two-dimensional clusters, allowing us to find the force on a cluster bounded by two parallel walls.     

Dynamics of soft and semisoft nematic elastomers

We analyze analytically and numerically the dynamics of how a nematic elastomer-an anisotropic rubber-responds elastically and orientationally to an imposed strain. Because positional and orientational degrees of freedom are coupled, the response is not the simple exponential one might expect for a viscous system. Indeed, as a result of this nonlinear coupling, the different modes decay in two qualitatively different ways: with either two distinct or with the same exponential laws, depending, respectively, on whether there is or there is not complete reorientation of the molecular long axes. In addition, at the special values of the strain that form the boundaries between different equilibrium behaviors, relaxation is much slower, i.e., it follows a power law.     

Anisotropic scalar field with cosmical time

A static, plane-symmetric scalar field of long range is considered in general relativity, and a one-parameter class of exact solutions with cosmical time is studied in harmonic coordinates. The geodetic equations are solved. A velocity-dependent acceleration field is found, acting attractively on the component of the velocity normal to the plane of symmetry, and repulsively on the component parallel to that plane. The manifold is complete. Test particles at rest are insensitive to it.     

Sur les courbes à développée intermédiaire circulaire

Sans résumé     

Sur les courbes représentées par ľľquation polaire

Rendiconti del Circolo Matematico di Palermo Series 1 -     

On the role of leptonic CPV phases in cLFV observables

The European Physical Journal C - We argue that high-quality data on the reaction $$e^+e^-\rightarrow \pi ^+\pi ^-\eta $$ will allow one to determine the doubly-virtual form factor $$\eta...     

Novel Bisphosphonates Derived from 1H‐Indazole, 1H‐Pyrazolo[3,4‐b]Pyridine,and 1H‐Pyrazolo[3,4‐b]Quinoline

Novel tetraethyl ethylene‐1,1‐bisphosphonate esters derived from 1H‐indazole, 1H‐pyrazolo[3,4‐b]pyridine, and 1H‐pyrazolo[3,4‐b]quinoline were synthesized by a Michael addition reaction of tetraethyl ethylidene‐1,1‐bisphosphonate with the corresponding heterocycle, using conventional heating and microwave‐assisted methods. The microwave‐assisted method provides shorter reaction times and better yields. The hydrolysis of bisphosphonates afforded the corresponding bisphosphonic acids or salt, using concentrated hydrochloric acid or TMSBr/collidine, respectively. All new compounds were fully characterized, and their structures were assigned using ¹H, ³¹P, and ¹³C NMR and IR spectroscopies and mass spectrometry. The molecular structure of compound 6 was confirmed by X‐ray diffraction studies.