Notes

Optical detection of a single rare-earth ion in a crystal
Center of Photonic Engineering (SCoPE), Pfaffenwaldring 57, D-70569 Stuttgart, Rare-earth-doped laser materials show strong prospects for quantum information storage and processing, as well as for biological imaging, due to their high-Q 4f↔4f optical transitions. However, the inability to optically detect single rare-earth dopants has prevented these materials from reaching their full potential. Here we detect a single photostable Pr(3+) ion in yttrium aluminium garnet nanocrystals with high contrast photon antibunching by using optical upconversion of the excited state population of the 4f↔4f optical transition into ultraviolet fluorescence. We also demonstrate on-demand creation of Pr(3+) ions in a bulk yttrium aluminium garnet crystal by patterned ion implantation. Finally, we show generation of local nanophotonic structures and cell death due to photochemical effects caused by upconverted ultraviolet fluorescence of praseodymium-doped yttrium aluminium garnet in the surrounding environment. Our study demonstrates versatile use of rare-earth atomic-size ultraviolet emitters for nanoengineering and biotechnological applications.

Rapid preparation of multifunctional surfaces for orthogonal ligation by Westfälische Wilhelms-Universität Münster, Corrensstrasse 40, 48149 Münster, Microcontact chemistry has been applied to patterned glass and silicon substrates by successive reaction of unprotected and monoprotected heterobifunctional linkers with alkene-terminated self-assembled monolayers (SAMs) to produce bi-, tri-, and tetrafunctional surfaces. Photochemical microcontact printing of an azide thiol linker followed by immobilization of an acid thiol linker on an undecenyl-terminated SAM results in a well-defined, micropatterned surface with terminal azide, acid, and alkene groups. Biologically relevant molecules (biotin, carbohydrates) have been selectively attached to the surface by means of orthogonal ligation chemistry, and the resulting microarrays display selective binding to fluorescently labeled proteins. Seebio Photoinitiator , tetrafunctional surface (azide, acid, alkene, and amine) can be prepared by an additional printing step of a tert-butyloxycarbonyl (Boc)-protected alkyne amine linker on the azide structures by using the copper(I)-catalyzed azide-alkyne Huisgen cycloaddition and subsequent removal of the protective group.Exchange Coupling Effects on the Magnetotransport Properties of Francisco de Quito, Quito 170901, Ecuador.We characterize the effect of ferromagnetic nickel nanoparticles (size ∼6 nm) on the magnetotransport properties of chemical-vapor-deposited (CVD) graphene. The nanoparticles were formed by thermal annealing of a thin Ni film evaporated on top of a graphene ribbon.

The magnetoresistance was measured while sweeping the magnetic field at different temperatures, and compared against measurements performed on pristine graphene. Our results show that, in the presence of Ni nanoparticles, the usually observed zero-field peak of resistivity produced by weak localization is widely suppressed (by a factor of ∼3), most likely due to the reduction of the dephasing time as a consequence of the increase in magnetic scattering. On the other hand, the high-field magnetoresistance is amplified by the contribution of a large effective interaction field. The results are discussed in terms of a local exchange coupling, J∼6 meV, between the graphene π electrons and the 3d magnetic moment of nickel. Interestingly, Applications of 6-butyl-n-hydroxynaphthimide trifluoromethanesulfonic acid in Cross-Coupling Reactions does not affect the intrinsic transport parameters of graphene, such as the mobility and transport scattering rate, which remain the same with and without Ni nanoparticles, indicating that the changes in the magnetotransport properties have a purely magnetic origin.Tailoring Diindenochrysene through Intramolecular Multi-Assemblies by C-F Bond Friedrich-Alexander University Erlangen-Nürnberg, Nikolaus-Fiebiger Str. 10, The unique nature of the alumina-mediated cyclodehydrofluorination gives the opportunity to execute the preprogrammed algorithm of the C-C couplings rationally built into a precursor.

Such multi-assemblies facilitate the construction of the carbon-skeleton, superseding the conventional step-by-step by the one-pot intramolecular assembly. In this work, the feasibility of the alumina-mediated C-F bond activation approach for multi-assembly is demonstrated on the example of a fundamental bowl-shaped polycyclic aromatic hydrocarbon (diindenochrysene) through the formation of all "missing" C-C bonds at the last step. Beside valuable insights into the reaction mechanism and the design of the precursors, a facile pathway enabling the two-step synthesis of diindenochrysene was elaborated, in which five C-C bonds form in a single synthetic step. It is shown that the relative positions of fluorine atoms play a crucial role in the outcome of the assembly and that governing the substituent positions enables the design of effective precursor molecules "programmed" for the consecutive C-C bond formations. In general, these findings push the state of the field towards the facile synthesis of sophisticated bowl-shaped carbon-based nanostructures through multi-assembly of fluoroarenes.© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
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