Filters

2016 - 201922020 - 20211

More filters

20223
Reset filters

Settings

Publisher: London : RSC Publishing × Subject: Functionalizations ×

Search Results

Now showing 1 - 3 of 3
  • Thumbnail Image
    Item
    Catalyst-free site-specific surface modifications of nanocrystalline diamond films via microchannel cantilever spotting
    (London : RSC Publishing, 2016) Davydova, Marina; de los Santos Pereira, Andres; Bruns, Michael; Kromka, Alexander; Ukraintsev, Egor; Hirtz, Michael; Rodriguez-Emmenegger, Cesar
    The properties of nanocrystalline diamond (NCD) films offer great potential for the creation of various sensing and photonic devices. A great challenge in order to materialize such applications lies in achieving the micrometrically resolved functionalization of NCD surfaces. In the present work, we introduce a facile approach to meet this challenge employing the novel strain-promoted alkyne–azide cycloaddition “click” chemistry reaction, a catalyst-free ligation protocol compatible with biomolecules. The ability to achieve well-resolved multicomponent patterns with high reproducibility is demonstrated, paving the way for the fabrication of novel devices based on micropatterned NCD films.
  • Thumbnail Image
    Item
    Sulfonated covalent triazine-based frameworks as catalysts for the hydrolysis of cellobiose to glucose
    (London : RSC Publishing, 2018) Artz, Jens; Delidovich, Irina; Pilaski, Moritz; Niemeier, Johannes; Kübber, Britta Maria; Rahimi, Khosrow; Palkovits, Regina
    Covalent triazine-based frameworks (CTFs) were synthesized in large scale from various monomers. The materials were post-synthetically modified with acid functionalities via gas-phase sulfonation. Acid capacities of up to 0.83 mmol g−1 at sulfonation degrees of up to 10.7 mol% were achieved. Sulfonated CTFs exhibit high specific surface area and porosity as well as excellent thermal stability under aerobic conditions (>300 °C). Successful functionalization was verified investigating catalytic activity in the acid-catalyzed hydrolysis of cellobiose to glucose at 150 °C in H2O. Catalytic activity is mostly affected by porosity, indicating that mesoporosity is beneficial for hydrolysis of cellobiose. Like other sulfonated materials, S-CTFs show low stability under hydrothermal reaction conditions. Recycling of the catalyst is challenging and significant amounts of sulfur leached out of the materials. Nevertheless, gas-phase sulfonation opens a path to tailored solid acids for application in various reactions. S-CTFs form the basis for multi-functional catalysts, containing basic coordination sites for metal catalysts, tunable structural parameters and surface acidity within one sole system.
  • Thumbnail Image
    Item
    Mixed-halide triphenyl methyl radicals for site-selective functionalization and polymerization
    (London : RSC Publishing, 2021) Chen, Lisa; Arnold, Mona; Blinder, Rémi; Jelezko, Fedor; Kuehne, Alexander J. C.
    Derivatives of the stable, luminescent tris-2,4,6-trichlorophenylmethyl (TTM) radical exhibit unique doublet spin properties that are of interest for applications in optoelectronics, spintronics, and energy storage. However, poor reactivity of the chloride-moieties limits the yield of functionalization and thus the accessible variety of high performance luminescent radicals. Here, we present a pathway to obtain mixed-bromide and chloride derivatives of TTM by simple Friedel–Crafts alkylation. The resulting radical compounds show higher stability and site-specific reactivity in cross-coupling reactions, due to the better leaving group character of the para-bromide. The mixed halide radicals give access to complex, and so far inaccessible luminescent open-shell small molecules, as well as polymers carrying the radical centers in their backbone. The new mixed-halide triphenyl methyl radicals represent a powerful building block for customized design and synthesis of stable luminescent radicals.