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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 1H 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 the inorganic core to the organic moiety was employed to tune the emission properties by trans‐cis isomerization of the double bond. In the case of the octafunctionalized nanocages (O‐POSS), this isomerization was monitored in the presence of Eu(III) cations and was accompanied by an evident colour change from blue (trans‐O‐POSS) to red (Eu@trans‐O‐POSS) and finally to green (cis‐O‐POSS) as consequence of the release of the metal cations. This behaviour, together with the easy dispersion of the dry powder and the possibility of coating as a film in presence of small amounts of solvent, makes the emissive solid promising for applications in materials science.

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 assumed by the triazole linkers, present in the nanosponge network, in affecting both the adsorption abilities of the materials towards the bioactive molecules, and the antiproliferative activity of the composites. This work puts forward an efficient strategy to prepare nanosponge based nanocarriers with three different cavities that could encapsulate two or more drug molecules with different physico-chemical properties.

A POSS functionalized with eight rigid and directional terpyridine arms was synthesized. After complexation with europium, a white light emission ascribed to the presence of combined contributions from the blue, green and red regions was detected.