One-atom-thick crystals are impermeable to atoms and molecules, but hydrogen ions (thermal protons) penetrate through them. We show that monolayers of graphene and boron nitride can be used to separate hydrogen ion isotopes. Using electrical measurements and mass spectrometry, we found that deuterons permeate through these crystals much slower than protons, resulting in a separation factor of ≈10 at room temperature. The isotope effect is attributed to a difference of ≈60 milli-electron volts between zero-point energies of incident protons and deuterons, which translates into the equivalent difference in the activation barriers posed by two-dimensional crystals. In addition to providing insight into the proton transport mechanism, the demonstrated approach offers a competitive and scalable way for hydrogen isotope enrichment.
The formation and use of iminyl radicals in novel and divergent hydroimination and iminohydroxylation cyclization reactions has been accomplished through the design of a new class of reactive O-aryl oximes. Owing to their low reduction potentials, the inexpensive organic dye eosin Y could be used as the photocatalyst of the organocatalytic hydroimination reaction. Furthermore, reaction conditions for a unique iminohydroxylation were identified; visible-light-mediated electron transfer from novel electron donor–acceptor complexes of the oximes and Et3N was proposed as a key step of this process.
The liquid-liquid interface provides a molecularly sharp, defect free focal plane for the assembly of solid materials. In this article we discuss the various materials which have been successfully assembled at the liquid/liquid interface such as metallic nanoparticles, Janus particles and carbon nanomaterials. Strategies to induce particle assembly include manipulation of surface chemistry, surface charge and potential control. Liquid/liquid assembly can be exploited to synthesise materials in situ and template preformed structures. We go on to discuss the difficulties encountered when attempting to fully understand the structure of assemblies present at the liquid/liquid interface and the development of experimental techniques to elucidate information about the structure, stability, chemical composition, and reactivity of interfacial assemblies.
Zum Ende des Sommers nimmt die Zahl der Insekten in Wald und Flur deutlich ab. Nur noch wenige Schmetterlinge gaukeln über blütenarme Wiesen. Doch einige häufige Nachtfalter‐Raupen sind gerade im September und Oktober kaum zu übersehen und ermöglichen somit interessante Beobachtungen im Herbst.
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