Analyse sehr kleiner Partikel mit der Mikrosonde

Zusammenfassung Sehr kleine Festkörperpartikel werden in einer Mikroschmelze aus Lithiumtetraborat unter Zugabe eines inneren Standards gelöst und mit der Mikrosonde quantitativ analysiert. Die Bestimmung der Menge an innerem Standard erfolgt durch mikroskopisches Ausmessen von Kriställchen des kubischen Systems.

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Analysis of very small particles by means of the microprobe

Summary Very small particles of solid substances are determined by the microprobe in melts of Li₂B₄O₇ using micro crucibles with addition of inner standards. The determination of the amount of inner standard is performed microscopically by measuring the size of small crystals of the cubic system.

Die Mittel zur Beschaffung der Mikrosonde wurden dankenswerterweise vom Bundesministerium für Wissenschaftliche Forschung zur Verfügung gestellt. Wir danken weiterhin der Fa. W. C. Heraeus, Hanau, für die Anfertigung der Mikrotiegel und der Hoechst AG (Herrn Dr. Kehler) für die Aufnahmen mit dem Rasterelektronenmikroskop.     

Exposing the Delocalized Cu−S π Bonds on the Au24Cu6(SPhtBu)22 Nanocluster and Its Application in Ring‐Opening Reactions

Bimetallic nanomaterials are of major importance in catalysis. A Au‐Cu bimetallic nanocluster was synthesized that is effective in catalyzing the epoxide ring‐opening reaction. The catalyst was analyzed by SCXRD and ESI‐MS and found to be Au₂₄Cu₆(SPhtBu)₂₂ (Au₂₄Cu₆ for short). Six copper atoms exclusively occupy the surface positions in two groups with three atoms for each, and each group was bonded with three thiolate ligands to give a planar motif reminiscent of a benzene ring. In the epoxide‐ring opening reaction, Au₂₄Cu₆ exhibited superior catalytic activity compared to other homometallic and Au‐Cu alloy NCs, such as Au₂₅ and Au_38?xCu_x. Control experiments and DFT calculations revealed that the π conjugation among the Cu?S bonds played a pivotal role. This study demonstrates a unique π conjugation established among the Cu?S bonds as a critical structural motif in the nanocluster, which facilitates the catalysis of a ring‐opening reaction.     

Bioactive Patchy Nanoparticles with Compartmentalized Cargoes for Simultaneous and Trackable Delivery

Recent years have seen an increased interest in the use of ABC triblock terpolymers to bottom‐up assemble multicompartment patchy nanoparticles. Despite these experimental and theoretical efforts, the applications of polymer‐based patchy nanoparticles remain rather limited. One of the major challenges that eclipses their potential is the lack of knowledge to selectively encapsulate cargoes within different compartments that are separated in the nanometer length scale. Here, strategies are reported to segregate two chemically distinct molecules in either the patches or core compartment of patchy nanoparticles that bear a (bioactive) sugar corona. The potential use of these bioactive patchy nanoparticles containing compartmentalized cargoes for simultaneous drug delivery with real‐time release monitoring capabilities is further demonstrated.