pH- and photo-switched release of guest molecules from mesoporous silica supports.

This paper proposes a new nanoscopic molecular movable gate-like functional hybrid system consisting of nanoscopic MCM-41-based material functionalized onto pore outlets with a saccharide derivative capable of interacting with boronic acid functionalized gold nanoparticles (AuNPs) acting as nanoscopic caps. The gating mechanism involves the reversible reaction between polyalcohols and boronic acids to form boronate esters. Functionalized AuNPs thus act as a suitable nanoscopic cap via the reversible formation of the corresponding boroester bonds with the saccharide derivative anchored on the external surface of the mesoporous silica-based solid.

Chromo-fluorogenic sensing of pyrophosphate in aqueous media using silica functionalised with binding and reactive units.

A chromogenic chemosensor for selective pyrophosphate sensing in aqueous environments has been developed using silica functionalised surfaces.

Controlled release of vitamin B2 using mesoporous materials functionalized with amine-bearing gate-like scaffoldings.

A study on the controlled release of vitamin B(2) in pure water from mesoporous silica-based materials containing a pH- and anion-controlled nano-supramolecular gate-like ensembles built up by anchoring suitable polyamines on the external surface is reported (solid S1). This solid contains the vitamin (the delivered molecule) onto the pores, whereas the amine-based gate-like ensemble is anchored on the pore outlets. To obtain solid S1 the mesoporous MCM-41 support was first synthesized using tetraethyl orthosilicate (TEOS) as hydrolytic inorganic precursor and the surfactant hexadecyltrimethylammonium bromide (CTAB) as porogen species.

Dual aperture control on pH- and anion-driven supramolecular nanoscopic hybrid gate-like ensembles.

The development of gate-like systems able to perform certain programmed functions is an interesting way of taking chemistry to the frontiers of nanoscience. In relation to this field, we report a complete study of the behavior of a pH-driven and anion-controlled nano-supramolecular gate-like ensemble obtained by anchoring suitable polyamines on the pore outlets of mesoporous materials of the type MCM-41 (solid N3-S). The release of an entrapped dye (Ru(bipy)3(2+)) from the pore voids into the bulk solution allows us to study the gating effect.