Investigation of the Photochromism of WO, TiO, and Composite WO-TiO Nanoparticles.

We report the synthesis of WO, TiO, and TiO-WO nanoparticles by a polyol route, with the objective of studying the influence of the preparation method on their photochromic properties. By combining transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and diffuse reflectance experiments, we show that low W concentrations and high ripening temperatures allow the preparation of WO nanoparticles with high photochromic efficiency. WO-TiO nanocomposites (NCs) prepared by the introduction of a TiO solution in a WO nanoparticle suspension exhibit a strong coloring photochromism, which is attributed to the TiO coating of the WO nanoparticles as it involves the formation of W-O-Ti oxo-bonds in place of W-ν defects.

Expanding the Toolbox of Chemoselective Modifications of Protein-Like Polymers at Methionine Residues.

Selective modifications at methionyl residues in proteins have attracted particular attention in recent years. Previously described methods to chemoselectively modify the methionine side chain in elastin-like polypeptides (ELPs) involved nucleophilic addition using alkyl halides or epoxides yielding a sulfonium group with a positive charge strongly affecting ELPs' physicochemical properties, in particular their thermal responsiveness. We herein explored the recently reported ReACT method (Redox-Activated Chemical Tagging) based on the use of oxaziridine derivatives, yielding an uncharged sulfimide as an alternative route for chemoselective modifications of methionine-containing ELPs in aqueous medium.