The short shelf-life of water-soluble quantum dots (QDs) due to colloidal instability represents a major drawback to their exploitation. This work examines the colloidal stability of PbS nanoparticles capped with dihydrolipoic acid–polyethylene glycol (DHLA–PEG) ligands terminated with functional groups such as –NH2, –COOH, OMe and –N3.\ud and their application for in vivo imaging. We prove a mechanism of colloidal instability and develop a strategy to produce for the first time stable PEG-capped PbS quantum dots with high quantum yield and optical emission in the first and the second near-infrared (NIR) windows of low absorption of biological tissues. The NIR imaging of in vivo\ud biodistribution is demonstrated at wavelengths 41000 nm, with benefits of reduced tissue absorption and light scattering. The stability, biocompatibility and potential for further QD functionalization open up realistic prospects for non-invasive bioimaging applications

This microreview highlights the utility of 1,4‐dithiane‐2,5‐diol (1) as a source for the in situ generation of 2‐mercaptoacetaldehyde (2), a versatile two‐carbon synthon featuring both electrophilic and nucleophilic reaction centres and widely utilized as an attractive platform for the preparation of sulfur‐containing molecules. We discuss the chemistry involved, mainly focusing on its applications to the construction of sulfur‐containing heterocyclic compounds including the thiophene and 1,3‐thiazole families and other different sulfur–nitrogen and sulfur–oxygen heterocycles that continue to be a pillar of organic synthesis as a result of their broad application in organic and medicinal chemistry.

No abstract