Sintesi e studio fotofisico di sistemi Eu@POSS: controllo dell’emissione attraverso isomeria cis-trans.

Pre- and post-modification of mixed cyclodextrin-calixarene co-polymers: A route towards tunability

Various pre-modified and post-modified cyclodextrin-calixarene hyper-reticulated co-polymers were synthesized, fully characterized by different techniques (FT-IR, 13C{1H} CP-MAS and LGFS solid-state NMR, thermogravimetry, porosimetry), and tested to assess their absorption abilities as nanosponges. The construction of the polymer network was accomplished exploiting the well-known CuAAC reaction between two different heptakis-6-azido-β-cyclodextrins and two different propargyloxy-calix[4]arenes. Post-modification was aimed to achieve the presence of ionizable (acidic or basic) groups on the polymer framework. Sequestration tests towards two model pollutant molecules surprisingly showed that …

Cover Feature: Tuneable Emission of Polyhedral Oligomeric Silsesquioxane Based Nanostructures that Self‐Assemble in the Presence of Europium(III) Ions: Reversible trans ‐to‐ cis Isomerization (ChemPlusChem 3/2020)

White light emitting silsesquioxane based materials: the importance of a ligand with rigid and directional arms

The synthesis of a novel polyhedral oligomeric silsesquioxane functionalized with eight rigid and directional terpyridine-based arms (Ter-POSS) was successfully achieved via a Sonogashira reaction. The POSS based ligand was extensively characterized using different techniques including 1H, 13C and 29Si NMR as well as UV-Vis and fluorescence spectroscopies. The assembly of these nano-caged units in the presence of different transition metal ions (Fe2+, Zn2+ and Cu2+) as well as of a cation from the lanthanides (Eu3+) was investigated using absorption and emission spectroscopies. The final materials display an evident emission in different regions of the visible spectrum as a function of the …

Chemical and pharmaceutical evaluation of the relationship between triazole linkers and pore size on cyclodextrin–calixarene nanosponges used as carriers for natural drugs

Mixed cyclodextrin–calixarene nanosponges were used to prepare some composites with the well known polyphenolic bioactive compounds quercetin and silibinin. The composites were characterized by means of different techniques (UV-vis, FT-IR, microcalorimetry, thermogravimetry), in order to assess their loading and thermal stability. The kinetics of release of the bioactive molecules into aqueous solution were studied at two different pH values (1.0, 6.4), which mimic typical physiological conditions. Finally the possible antiproliferative effects in vitro were assayed towards three triple negative breast cancer cell lines (SUM 149, SUM 159 and MDA-MB-23). Our results point out the role assume…

Tuneable Emission of Polyhedral Oligomeric Silsesquioxane Based Nanostructures that Self-Assemble in the Presence of Europium(III) Ions: Reversible trans-to-cis Isomerization

[EN] Hybrid nanostructures with switchable and reversible "blue-red-green" emission were efficiently synthesized. These nanostructures comprise polyhedral oligomeric silsesquioxanes (POSS) that behave as a nanocage that can be functionalized with terpyridine-based organic ligands, which can be easily complexed with europium (III) ions. The complexes were characterized by UV-Vis and fluorescence spectroscopy and their stoichiometry was also confirmed by H-1 NMR spectroscopy. In the presence of the Eu(III) ions, the octafunctionalized nanocages self-assemble to form 3D architectures that display an intense red-emission, especially in the solid state. The presence of an alkenyl group bridging …

Modified Carbon Nanoforms Systems for Asymmetric Catalysis