Vinyl nosylates as partner in copper and silver co-catalyzed Sonogashira cross-coupling reactions

Vinyl nosylates, readily obtained from β-dicarbonyl derivatives, could be efficiently engaged in Sonogashira cross-coupling reactions, either cocatalyzed by copper or silver salts. The para-nitrobenzenesulfonate (nosylate) group allows this coupling to be performed under very mild conditions (room temperature). These new leaving group and mild conditions could be applied to the synthesis of acetylenic coumarinyl derivatives and to the total synthesis of an acetylenic monoterpene natural product, named cleviolide.     

Exit Times, Moment Problems and Comparison Theorems

We establish comparison theorems involving exit time moments for Brownian motion and eigenvalues for the Dirichlet problem for domains in a complete Riemannian manifold. These theorems are closely related to isoperimetric properties of the ambient manifold.     

The Prospect of Dimensionality in Porous Semiconductors

With the advent of silicon-based semiconductors, a plethora of previously unknown technologies became possible. The development of lightweight low-dimensional organic semiconductors followed soon after. However, the efficient charge/electron transfers enabled by the non-porous 3D structure of silicon is rather challenging to be realized by their (metal-)organic counterparts. Nevertheless, the demand for lighter, more efficient semiconductors is steadily increasing resulting in a growing interest in (metal-)organic semiconductors. These novel materials are faced with a variety of challenges originating from their chemical design, their packing and crystallinity. Although the effect of molecular design is quite well understood, the influence of dimensionality and the associated change in properties (porosity, packing, conjugation) is still an uncharted area in (metal-)organic semiconductors, yet highly important for their practical utilization. In this Minireview, an overview on the design and synthesis of porous semiconductors, with a particular emphasis on organic semiconductors, is presented and the influence of dimensionality is discussed.     

Synchronization of simplest two-component Hartley’s chaotic circuits: influence of channel

Firstly, the synchronization problem of the simplest two-component Hartley chaotic systems is considered. A simple and effective controller is used to achieve synchronization between the drive and response systems. The proposed controller is built around a linear and a nonlinear parts with each contributing to the achievement of the synchronization process. The stability of the drive–response systems framework is proved through the Lyapunov stability theory. Secondly, the impact of channel on the signal coming from the drive system to synchronize the response system is taken into consideration. In this second part, the conditions to obtain synchronization between both master and slave systems are investigated. For the purpose of illustration, PSpice simulations are given as complement of the numerical analysis.