Synthesis and characterization of a novel polyester derived from substituted terfluorene

Poly(1,6‐hexane‐9,9,9′,9′,9″,9″‐hexahexyl‐7,2′;7′,2″‐terfluorene‐2,7″‐dicarboxylate) (PTFHHC6) has been synthesized and characterized. This polymer exhibits strong emission in the blue range, both in solution (quantum yield of 76%) and in the solid state. Moreover, PTFHHC6 presents some advantages over other polyfluorene derivatives since its solid‐state fluorescence spectrum does not show any excimer formation and does not vary upon thermal treatment. Electrochemical measurements have revealed a reversible p‐n dopable polymer. This aromatic polyester shows promising optical and electrical properties for the development of blue light‐emitting diodes.     

Exploring Superacid-Promoted Skeletal Reorganization of Aliphatic Nitrogen-Containing Compounds

Here we report a method to reorganize the core structure of aliphatic unsaturated nitrogen-containing substrates exploiting polyprotonation in superacid solutions. The superelectrophilic activation of N-isopropyl systems allows for the selective formal C_sp3−H activation/cyclization or homologation / functionalization of nitrogen-containing substrates. This study also reveals that this skeletal reorganization can be controlled through protonation interplay. The mechanism of this process involves an original sequence of C−N bond cleavage, isopropyl cation generation and subsequent C−N bond and C−C bond formation. This was demonstrated through in situ NMR analysis and labelling experiments, also confirmed by DFT calculations.     

Sydnone-Cyanines as Clickable Probes for Fluorescent Labelling

The synthesis of four clickable sydnone-heptamethine cyanine derivatives is described in this article. The synthetic route is based on a palladium-cross coupling reactions of sydnone boronates affording the desired sydnone-cyanine conjugates in only five steps. These compounds were shown to react smoothly with cyclooctynes to form the corresponding pyrazoles clicked products quantitatively at room temperature and with rate constants up to 18 m ⁻¹ ⋅ s⁻¹, affording interesting new tools for biorthogonal fluorescent labelling of (bio)molecules. Fluorescence properties of both sydnone- and pyrazole-cyanines are described, as well.     

Modern Strategies for Carbon Isotope Exchange

In contrast to stable and natural abundant carbon-12, the synthesis of organic molecules with carbon (radio)isotopes must be conceived and optimized in order to navigate through the hurdles of radiochemical requirements, such as high costs of the starting materials, harsh conditions and radioactive waste generation. In addition, it must initiate from the small cohort of available C-labeled building blocks. For long time, multi-step approaches have represented the sole available patterns. On the other side, the development of chemical reactions based on the reversible cleavage of C−C bonds might offer new opportunities and reshape retrosynthetic analysis in radiosynthesis. This review aims to provide a short survey on the recently emerged carbon isotope exchange technologies that provide effective opportunity for late-stage labeling. At present, such strategies have relied on the use of primary and easily accessible radiolabeled C1-building blocks, such as carbon dioxide, carbon monoxide and cyanides, while the activation principles have been based on thermal, photocatalytic, metal-catalyzed and biocatalytic processes.