Reversing the stereoselectivity of intramolecular [2+2] photocycloaddition utilizing cucurbit[8]uril as a molecular flask.

Macrocyclic hosts, such as cucurbit[8]uril (CB8), can significantly influence the outcomes of chemical reactions involving encapsulated reactive guests. In this study, we demonstrate that CB8 completely reverses the stereoselectivity of intramolecular [2+2] photo-cycloaddition reactions. Notably, it was also found that CB8 can trigger the unreactive diene to be reactive.

Skeletal Editing-Nitrogen Deletion of Secondary Amines by Anomeric Amide Reagents.

Late-stage modification is highly desirable for the diversification and modification of biologically active compounds. Peripheral editing (e.g., C-H activation) has been the predominant methodology, whereas skeletal editing is in its infancy. The single-atom N-deletion using anomeric amide reagents constitutes a powerful tool to modify the underlying molecular skeletons of secondary amines. N-pivaloyloxy-N-alkoxyamide is easily prepared on a large scale and promotes C-C bond formation in good yields under the extrusion of N2 for a variety of (cyclic) aliphatic amines. The exploitation of widely available amines allows the use of existing amine synthesis protocols to translate into the construction of new C-C bonds, enabling ring contraction and the potential for structure optimization of biologically active compounds.

A Brief History of OLEDs-Emitter Development and Industry Milestones.

Organic light-emitting diodes (OLEDs) have come a long way ever since their first introduction in 1987 at Eastman Kodak. Today, OLEDs are especially valued in the display and lighting industry for their promising features. As one of the research fields that equally inspires and drives development in academia and industry, OLED device technology has continuously evolved over more than 30 years. OLED devices have come forward based on three generations of emitter materials relying on fluorescence (first generation), phosphorescence (second generation), and thermally activated delayed fluorescence (third generation). Furthermore, research in academia and industry toward the fourth generation of OLEDs is in progress. Excerpts from the history of green, orange-red, and blue OLED emitter development on the side of academia and milestones achieved by key players in the industry are included in this report.

Samarium Polyarsenides Derived from Nanoscale Arsenic.

Zintl phases of arsenic and molecular compounds containing Zintl-type polyarsenide ions are of fundamental interest in basic and applied sciences. Unfortunately, the most obvious and reactive arsenic source for the preparation of defined molecular polyarsenide compounds, yellow arsenic As4 , is very inconvenient to prepare and neither storable in pure form nor easy to handle. Herein, we present the synthesis and reactivity of elemental As0 nanoparticles (As0 Nano , d=7.2±1.8 nm), which were successfully utilized as a reactive arsenic source in reductive f-element chemistry. Starting from [Cp*2 Sm] (Cp*=η5 -C5 Me5 ), the samarium polyarsenide complexes [(Cp*2 Sm)2 (µ-η2 :η2 -As2 )] and [(Cp*2 Sm)4 As8 ] were obtained from As0 nano , thereby generating the largest molecular polyarsenide of the f-elements and circumventing the use of As4 in preparative chemistry.