Metal‐Free Triplet Phosphors with High Emission Efficiency and High Tunability

Design of highly efficient phosphorescent emitters based on metal‐ and heavy atom‐free boron compounds has been demonstrated by taking advantage of the singlet fission process. The combination of a suitable molecular scaffold and appropriate electronic nature of the substituents has been utilized to tailor the phosphorescence emission properties in solution, neat solid, and in doped PMMA thin films.     

Estimation of band alignment at CdS/Cu2ZnSnS4 hetero-interface by direct XPS measurements

This paper aims to estimate the band alignment to CdS/CZTS hetero-interface by direct X-ray photoelectron spectroscopy (XPS) measurements. XPS was used to determinate the valence-band offset (VBO) directly by determining the valence band positions at the hetero-interface. The conduction band offset (CBO) value was estimated based on the band gap measurements by UV/Visible spectroscopy and VBO measurements. The position of valence band (VB) changes close to the CdS-CZTS interface and the CBO is cliff-like. The band alignment diagram indicates that the CdS-CZTS interface heterojunction is type II.     

Chiral N‐Heterocyclic Carbene Ligands Enable Asymmetric C−H Bond Functionalization

The asymmetric functionalization of C?H bond is a particularly valuable approach for the production of enantioenriched chiral organic compounds. Chiral N‐heterocyclic carbene (NHC) ligands have become ubiquitous in enantioselective transition‐metal catalysis. Conversely, the use of chiral NHC ligands in metal‐catalyzed asymmetric C?H bond functionalization is still at an early stage. This minireview highlights all the developments and the new advances in this rapidly evolving research area.     

A Molecular Strategy to Lock‐in the Conformation of a Perylene Bisimide‐Derived Supramolecular Polymer

Locking‐in the conformation of supramolecular assemblies provides a new avenue to regulate the (opto)electronic properties of robust nanoscale objects. In the present contribution, we show that the covalent tethering of a perylene bisimide (PBI)‐derived supramolecular polymer with a molecular locker enables the formation of a locked superstructure equipped with emergent structure–function relationships. Experiments that exploit variable‐temperature ground‐state electronic absorption spectroscopy unambiguously demonstrate that the excitonic coupling between nearest neighboring units in the tethered superstructure is preserved at a temperature (371 K) where the pristine, non‐covalent assembly exists exclusively in a molecularly dissolved state. A close examination of the solid‐state morphologies reveals that the locked superstructure engenders the formation of hierarchical 1D materials which are not achievable by unlocked assemblies. To complement these structural attributes, we further demonstrate that covalently tethering a supramolecular polymer built from PBI subunits enables the emergence of electronic properties not evidenced in non‐covalent assemblies. Using cyclic voltammetry experiments, the elucidation of the potentiometric properties of the locked superstructure reveals a 100‐mV stabilization of the conduction band energy when compared to that recorded for the non‐covalent assembly.     

Capturing the Monomeric (L)CuH in NHC‐Capped Cyclodextrin: Cavity‐Controlled Chemoselective Hydrosilylation of α,β‐Unsaturated Ketones

The encapsulation of copper inside a cyclodextrin capped with an N‐heterocyclic carbene (ICyD) allowed both to catch the elusive monomeric (L)CuH and a cavity‐controlled chemoselective copper‐catalyzed hydrosilylation of α,β‐unsaturated ketones. Remarkably, (α‐ICyD)CuCl promoted the 1,2‐addition exclusively, while (β‐ICyD)CuCl produced the fully reduced product. The chemoselectivity is controlled by the size of the cavity and weak interactions between the substrate and internal C?H bonds of the cyclodextrin.     

Numerical study of two-airfoil arrangements by a discrete vortex method

Theoretical and Computational Fluid Dynamics - The aerodynamic characteristics of two neighboring airfoils are greatly different from those of a single airfoil, for both attached and detached flow...     

Sample Entropy as a Tool to Assess Lumbo-Pelvic Movements in a Clinical Test for Low-Back-Pain Patients

Low back pain (LBP) obviously reduces the quality of life but is also the world’s leading cause of years lived with disability. Alterations in motor response and changes in movement patterns are expected in LBP patients when compared to healthy people. Such changes in dynamics may be assessed by the nonlinear analysis of kinematical time series recorded from one patient’s motion. Since sample entropy (SampEn) has emerged as a relevant index measuring the complexity of a given time series, we propose the development of a clinical test based on SampEn of a time series recorded by a wearable inertial measurement unit for repeated bending and returns (b and r) of the trunk. Twenty-three healthy participants were asked to perform, in random order, 50 repetitions of this movement by touching a stool and another 50 repetitions by touching a box on the floor. The angular amplitude of the b and r movement and the sample entropy of the three components of the angular velocity and acceleration were computed. We showed that the repetitive b and r “touch the stool” test could indeed be the basis of a clinical test for the evaluation of low-back-pain patients, with an optimal duration of 70 s, acceptable in daily clinical practice.     

An Efficient RuII–RhIII–RuII Polypyridyl Photocatalyst for Visible‐Light‐Driven Hydrogen Production in Aqueous Solution

The development of multicomponent molecular systems for the photocatalytic reduction of water to hydrogen has experienced considerable growth since the end of the 1970s. Recently, with the aim of improving the efficiency of the catalysis, single‐component photocatalysts have been developed in which the photosensitizer is chemically coupled to the hydrogen‐evolving catalyst in the same molecule through a bridging ligand. Until now, none of these photocatalysts has operated efficiently in pure aqueous solution: a highly desirable medium for energy‐conversion applications. Herein, we introduce a new ruthenium–rhodium polypyridyl complex as the first efficient homogeneous photocatalyst for H₂ production in water with turnover numbers of several hundred. This study also demonstrates unambiguously that the catalytic performance of such systems linked through a nonconjugated bridge is significantly improved as compared to that of a mixture of the separate components.     

Monitoring and Quantifying the Passive Transport of Molecules Through Patch–Clamp Suspended Real and Model Cell Membranes

Transport of active molecules across biological membranes is a central issue for the success of many pharmaceutical strategies. Herein, we combine the patch–clamp principle with amperometric detection for monitoring fluxes of redox‐tagged molecular species across a suspended membrane patched from a macrophage. Solvent‐ and protein‐free lipid bilayers (DPhPC, DOPC, DOPG) patched from single‐wall GUV have been thoroughly investigated and the corresponding fluxes measurements quantified. The quality of the patches and their proper sealing were successfully characterized by electrochemical impedance spectroscopy. This procedure appears versatile and perfectly adequate to allow the investigation of transport and quantification of the transport properties through direct measurement of the coefficients of partition and diffusion of the compound in the membrane, thus offering insight on such important biological and pharmacological issues.     

Supramolecular Luminescent Lanthanide Dimers for Fluoride Sequestering and Sensing

Lanthanide complexes (Ln=Eu, Tb, and Yb) that are based on a C₂‐symmetric cyclen scaffold were prepared and characterized. The addition of fluoride anions to aqueous solutions of the complexes resulted in the formation of dinuclear supramolecular compounds in which the anion is confined into the cavity that is formed by the two complexes. The supramolecular assembly process was monitored by UV/Vis absorption, luminescence, and NMR spectroscopy and high‐resolution mass spectrometry. The X‐ray crystal structure of the europium dimer revealed that the architecture of the scaffold is stabilized by synergistic effects of the Eu? F? Eu bridging motive, π stacking interactions, and a four‐component hydrogen‐bonding network, which control the assembly of the two [EuL] entities around the fluoride ion. The strong association in water allowed for the luminescence sensing of fluoride down to a detection limit of 24 nM .