New Trick for an Old Ligand! The Sensing of Zn(II) Using a Lanthanide Based Ternary Yb(III)-cyclen-8-hydroxyquinoline System As a Dual Emissive Probe for Displacement Assay

A novel near-infrared (NIR) emissive lanthanide-based zinc sensor was designed, based on the self-assembly in aqueous solution between the nonemissive coordinatively unsaturated Yb­(III) cyclen complex <b>2·Yb</b> and the sulfonated 8-hydroxyquinoline (<b>8-HQS</b>) chromophore, which was employed as a sensitizing antenna. The resulting ternary complex, <b>2·Yb·8-HQS</b>, displayed metal-centered emission in the NIR range upon excitation of the antenna with high quantum yield of <i>Q</i> = 0.23 ± 0.03% in pH 7.4 buffered aqueous solution; demonstrating efficient sensitization from <b>8-HQS</b>. The addition of zinc led to quenching of the NIR emission as a result of the dissociation of the luminescent ternary <b>2·Yb·8-HQS</b> complex, where the <b>8-HQS</b> antenna was displaced from the Yb­(III) center in favor of the formation of more stable chelates with Zn­(II). These newly formed Zn­(II) complexes were shown to exhibit strong green fluorescence; allowing for the simultaneous sensing of Zn­(II) both within the visible and the NIR regions at physiological pH in competitive media. Furthermore, <b>2·Yb·8-HQS</b> was shown to be able to detect Zn­(II) with good selectivity and in a reversible manner, even in the presence of competitive group (I) and (II) metal ions as well as in the presence of several biologically important d-metal ions

Lanthanide-Functionalized Nanoparticles as MRI and Luminescent Probes for Sensing and/or Imaging Applications

The combination of lanthanides and nanoparticles to develop new hybrid nanomaterials has become a highly topical area of research in the field of sensing, biomedical imaging, drug delivery, etc. However, these novel nanomaterials have to be carefully designed to ensure that the unique properties conveyed by each component, i.e., lanthanide ions and nanoparticles, are maximized and not negatively affected by one another. In this Forum Article, the main advances in the design of lanthanide-based nanoparticles will be discussed, with the first part focusing on the design of gadolinium­(III)-based nanoparticles and their use as magnetic resonance imaging agents. The second part will then describe the main and most recent designs of luminescent lanthanide-based nanoparticles and their applications as sensors or imaging agents, with a special emphasis on our contribution to this area

Efficient Quenching of TGA-Capped CdTe Quantum Dot Emission by a Surface-Coordinated Europium(III) Cyclen Complex

Extremely efficient quenching of the excited state of aqueous CdTe quantum dots (QDs) by photoinduced electron transfer to a europium cyclen complex is facilitated by surface coordination to the thioglycolic acid capping ligand. The quenching dynamics are elucidated using steady-state emission and picosecond transient absorption