Linear oxygen‐donor ligands derived from gallic acid methyl ester: ligand synthesis and preliminary coordination studies

The new ligands 3a ‐ c‐H ₄ with two catechol‐type oxygen‐donor binding sites and ether‐linked spacers are synthesized in three step procedures starting from gallic acid methyl ester 4 . After protection of two OH‐functions as benzophenone ketal, a Williamson ether synthesis introduces the spacer, and finally the ketal is removed again. Preliminary coordination studies with 3a (or 3b , 3c ) and titanium(IV) ions show that dinuclear triple‐stranded complexes M₄[( 3a )₃Ti₂] (and K₄[( 3b / c )₃Ti₂]) are formed in the presence of alkali metal (M = Li, Na, K, Cs) as well as ammonium cations (M = NH₄, PhCH₂NH₃, i‐Pr₂NH₂).     

Gas Generators for Deep Drawing Applications

Experiments are described, which use gas generator materials as a driving force in a deep drawing process. Two different tools for low and high pressure ranges were constructed. During the work a new gas generator material was developed, which shows a low slag formation and reduced combustion temperature. Decomposition kinetics and interior ballistic behavior were characterized. Materials tested were steel, stainless steel and aluminum with different thicknesses. The results show that gas generators are a suitable tool for deep drawing applications. The performance of the gas generator process is directly comparable to the hydroforming process, but the time for the drawing cycle is much faster with the new method.     

Sterically Enhanced Control of Enzyme-Assisted DNA Assembly**

Traditional methods for the assembly of functionalised DNA structures, involving enzyme restriction and modification, present difficulties when working with small DNA fragments (<100 bp), in part due to a lack of control over enzymatic action during the DNA modification process. This limits the design flexibility and range of accessible DNA structures. Here, we show that these limitations can be overcome by introducing chemical modifications into the DNA that spatially restrict enzymatic activity. This approach, sterically controlled nuclease enhanced (SCoNE) DNA assembly, thereby circumvents the size limitations of conventional Gibson assembly (GA) and allows the preparation of well-defined, functionalised DNA structures with multiple probes for specific analytes, such as IL-6, procalcitonin (PCT), and a biotin reporter group. Notably, when using the same starting materials, conventional GA under typical conditions fails. We demonstrate successful analyte capture based on standard and modified sandwich ELISA and also show how the inclusion of biotin probes provides additional functionality for product isolation.     

Wear Behavior of Roller-Burnished High Interstitial Austenitic Stainless Steel Parts in Glass-Reinforced Plastic Melt

Herein this investigation, profiled high interstitial austenitic stainless steel parts are burnished on a profile-rolling machine, and afterward, the wear behavior is analyzed in a melt of glass-reinforced polypropylene. Wear and corrosion resistance are significant properties of steel parts in the plastics and food industries. The high work-hardening ability of high interstitial austenitic stainless steel enables burnishing parts with a significant local hardness to increase up to maximum values of ≈600 HV 1. Wear tests on a recently developed test stand reveal that the burnished austenitic stainless steel surface performs similarly to a nitrided surface of the standard nitriding steel 31CrMoV9 + QT with a hardness of ≈830 HV 0.5. Regarding the given advantage of corrosion resistance, it is concluded that roller burnishing supports the applicability of high interstitial austenitic stainless steel in plastics and food industries.     

Dendri-LEC Family: Establishing the Bright Future for Dendrimer Emitters in Traditional and Graphene-Based Light-Emitting Electrochemical Cells

A rational implementation and optimization of thermally activated delayed fluorescent (TADF) dendrimer emitters in light-emitting electrochemical cells (LECs) sets in the Dendri-LEC family. They feature outstanding stabilities (90/1050 h for green/yellow devices) that are comparable to the best green/yellow Ir(III)-complexes (450/500 h) and conjugated polymers (33/5500 h), while offering benefits of low-cost synthesis and easy upscaling. In particular, a fundamental molecular design that capitalizes on exchanging peripheral substituents (tert-butyl vs methoxy) to tune photophysical, electrochemical, morphological, and ion conductivity features in thin films is rationalized by temperature-dependent steady-state and time-resolved emission spectroscopy, cyclic voltammetry, atomic force microscopy, and electrochemical impedance spectroscopy techniques. Herein, a TADF mechanism associated to a reduced photoluminescence quantum yield, but an enhanced electrochemical stability and ion conductivity enables to clarify the reduced device efficiency and brightness (4.0 lm W⁻¹@110 cd m⁻² vs 3.2 lm W⁻¹@55 cd m⁻²) and increased stability (90 vs 1050 h) upon using methoxy groups. What is more, this substitution enables an excellent compatibility with biogenic electrolytes keeping device performances (1.9 lm W⁻¹@35 cd m⁻² and 1300 h), while graphene-devices achieve on par figures to traditional indium–tin oxide-devices. Overall, this work establishes the bright future of dendrimer emitters toward highly stable and truly sustainable lighting sources.     

Chiral Seeded Growth of Gold Nanorods Into Fourfold Twisted Nanoparticles with Plasmonic Optical Activity

A robust and reproducible methodology to prepare stable inorganic nanoparticles with chiral morphology may hold the key to the practical utilization of these materials. An optimized chiral growth method to prepare fourfold twisted gold nanorods is described herein, where the amino acid cysteine is used as a dissymmetry inducer. Four tilted ridges are found to develop on the surface of single-crystal nanorods upon repeated reduction of HAuCl₄, in the presence of cysteine as the chiral inducer and ascorbic acid as a reducing agent. From detailed electron microscopy analysis of the crystallographic structures, it is proposed that the dissymmetry results from the development of chiral facets in the form of protrusions (tilted ridges) on the initial nanorods, eventually leading to a twisted shape. The role of cysteine is attributed to assisting enantioselective facet evolution, which is supported by density functional theory simulations of the surface energies, modified upon adsorption of the chiral molecule. The development of R-type and S-type chiral structures (small facets, terraces, or kinks) would thus be non-equal, removing the mirror symmetry of the Au NR and in turn resulting in a markedly chiral morphology with high plasmonic optical activity.