Rhodium(II)-Catalyzed CH Insertions with {[(4-Nitrophenyl)sulfonyl]imino}phenyl-λ3-iodane

The [Rh₂(OAc)₄]-catalyzed decomposition of {[(4-nitrophenyl)sulfonyl]imino}phenyl-λ³-iodane (NsN?IPh) resulted in formal insertions into CH bonds, activated by phenyl or vinyl groups, or by O-substituents. Scope and limitations of the reaction were investigated. Yields of up to 84% were achieved in the most favorable cases. Yields were enhanced by electron-releasing substituents and decreased by steric hindrance. Aziridination competed with allylic insertion with olefinic substrates. The insertion reaction proceeded with retention of configuration. With chiral Rh^II catalysts, a modest asymmetric induction was observed. A mechanism involving direct insertion by a Rh-complexed nitrene into the CH bond is proposed.     

Analysis of car door closing sound quality

The perception of the noise coming from a car’s door closure has been analyzed, the focus being put on the image of the quality of the car that the listener can have in mind while hearing the sound. Different experiments have been realized: a free sorting experiment for reducing the number of stimuli without any loss of generality, paired comparisons with similarity and preference ratings and, finally, free verbalizations analysis. The results have agreed on the importance of two timbre parameters, the frequency balance of the sound and its cleanness (only one temporal event should be audible). In particular, even if loudness had appeared as the most important sound feature in previously published studies, it did not in this one; the reason is probably that previous studies had focused on annoyance creating by sounds.In a more general way, this study has proved the stability of the perceptual space derived from two different methods: a multi-dimensional analysis of similarity ratings and the analysis of free verbalizations.     

De Novo Left‐Handed Synthetic Peptidomimetic Foldamers

The development of peptidomimetic helical foldamers with a wide repertoire of functions is of significant interest. Herein, we report the X‐ray crystal structures of a series of homogeneous l ‐sulfono‐γ‐AA foldamers and elucidate their folding conformation at the atomic level. Single‐crystal X‐ray crystallography revealed that this class of oligomers fold into unprecedented dragon‐boat‐shaped and unexpected left‐handed helices, which are stabilized by the 14‐hydrogen‐bonding pattern present in all sequences. These l ‐sulfono‐γ‐AApeptides have a helical pitch of 5.1 Å and exactly four side chains per turn, and the side chains lie perfectly on top of each other along the helical axis. 2D NMR spectroscopy, computational simulations, and CD studies support the folding conformation in solution. Our results provide a structural basis at the atomic level for the design of novel biomimetics with a precise arrangement of functional groups in three dimensions.     

A hybrid Finite Integration–Finite Volume Scheme

A hybridized scheme for the numerical solution of transient electromagnetic field problems is presented. The scheme combines the Finite Integration Technique (FIT) and the Finite Volume Method (FVM) in order to profit from the computational efficiency of the FIT while taking advantage of the superior dispersive properties of the FVM. The scheme is based on the longitudinal–transverse (LT) splitting of the discrete curl operator. The FIT is employed for discretizing the two-dimensional subproblem while the one-dimensional problem is discretized according to the FVM. The scheme offers benefits for the simulation of multiscale setups, where the size of the computational domain along one preferred direction is electrically much larger than along the others. In such situations, the accumulation of dispersion errors within hundreds of thousands of time steps usually deteriorates the solution accuracy. The hybrid scheme is applied in combination with adaptive mesh refinement, yielding an efficient scheme for multiscale applications.     

Control of light transmission through opaque scattering media in space and time

We report the first experimental demonstration of combined spatial and temporal control of light transmission through opaque media. This control is achieved by solely manipulating spatial degrees of freedom of the incident wave front. As an application, we demonstrate that the present approach is capable of forming bandwidth-limited ultrashort pulses from the otherwise randomly transmitted light with a controllable interaction time of the pulses with the medium. Our approach provides a new tool for fundamental studies of light propagation in complex media and has the potential for applications for coherent control, sensing and imaging in nano- and biophotonics.