Hexametaphosphate‐Capped Silica Mesoporous Nanoparticles Containing Cu^II Complexes for the Selective and Sensitive Optical Detection of Hydrogen Sulfide in Water

Abstract

CuII‐macrocycle functionalized hexametaphosphate‐capped silica mesoporous nanoparticles have been prepared and used for the selective and sensitive detection of hydrogen sulfide in aqueous environments. The possibility of using different metal complexes combined with different capping anions and choice of different dyes or other sensing molecules as indicators makes this new protocol highly appealing for the preparation of new sensing systems for sulfide detection in different environments.

Capped Mesoporous Silica Nanoparticles for the Selective and Sensitive Detection of Cyanide

“…As it can be seen, none of the tested chemicals were able to induce cargo delivery, pointing toward a highly selective response of NP3 solid toward cyanide anion. We recently reported hexametaphosphate‐capped nanoparticles functionalized with a Cu II macrocyclic complex, which were selectively uncapped only upon hydrogen sulfide addition . The previous and current results indicate that the selectivity of the hexametaphosphate‐capped nanoparticles can be properly addressed by changing the metal‐macrocyclic subunits grafted on their surface.…”

“…The final solid NP3 was obtained by stirring of NP2 with sodium hexametaphosphate in water (see Scheme and the Supporting Information for details). This specific reaction sequence (loading–functionalization–capping) provides the best results in terms of functionalization efficiency and preservation of dye content along the different steps, as also tested in previous analogous works . Reactions carried out on loaded silica nanoparticles were performed in the presence of excess free [Ru(bipy) 3 ] 2+ (see the Supporting Information) in order to reduce uncontrolled dye release, although it cannot be completely prevented.…”

“…The signalling paradigm relies on a demetallation of the Ni II complex induced by cyanide anion, which would uncap the pores with subsequent dye release. This paradigm has been recently used by us to prepare gated materials for the selective detection of hydrogen sulfide . Furthermore, and as far as we know, NP3 is the first capped material used for the selective and sensitive detection of cyanide anion.…”

Anions as Triggers in Controlled Release Protocols from Mesoporous Silica Nanoparticles Functionalized with Macrocyclic Copper(II) Complexes

“…Based on this observation, it was easy to prepare capped solids SC1‐mPh and SC3‐mPh by the simple addition of sodium hexametaphosphate to suspensions of nanoparticle SC1 or SC3 , respectively. The synthesis of SC3‐mPh has been recently published by our group as a communication …”

Overview of the Evolution of Silica-Based Chromo-Fluorogenic Nanosensors

“…Hydrogen sulfide (HS − ) was detected using MSNs capped with a coordination complex using a demetallation process. The probe, based on MSNs, was loaded with [Ru(bipy) 3 ]Cl 2 , functionalized with a Cu 2+ -triazapyridinophane complex, and capped with the bulky anion hexametaphosphate through electrostatic interactions with the positively charged Cu 2+ complex [54]. In the presence of HS − , the demetallation of Cu 2+ resulted in dye release.…”