No abstract

Iron (II) tris(2,2′-bipyridine) complexes, [Fe(bpy)3]2+, have been synthesized and immobilized in organosulfonate-functionalized nanostructured silica thin films taking advantage of the stabilization of [Fe(H2O)6]2+ species by hydrogen bonds to the anionic sulfonate moieties grafted to the silica nanopores. In a first step, thiol-based silica films have been electrochemically generated on indium tin oxide (ITO) substrates by co-condensation of 3-mercaptopropyltrimethoxysilane (MPTMS) and tetraethoxysilane (TEOS). Secondly, the thiol function has been modified to sulfonate by chemical oxidation using hydrogen peroxide in acidic medium as an oxidizing agent. The immobilization of [Fe(bpy)3]2+ complexes has been performed in situ in two consecutive steps: (i) impregnation of the sulfonate functionalized silica films in an aqueous solution of iron (II) sulfate heptahydrate; (ii) dipping of the iron-containing mesostructures in a solution of bipyridine ligands in acetonitrile. The in situ formation of the [Fe(bpy)3]2+ complex is evidenced by its characteristic optical absorption spectrum, and elemental composition analysis using X-ray photoelectron spectroscopy. The measured optical and electrochemical properties of immobilized [Fe(bpy)3]2+ complexes are not altered by confinement in the nanostructured silica thin film.

The Cover Feature illustrates the use of CO2 as a C1‐organic building block to electrochemically synthetize spiropyran switches. More information can be found in the Research Article by S. Santiago et al.

This manuscript deals with carbon capture and utilization to synthetize high-added chemicals using CO 2 as a C1-organic building block for CÀ C bond formation. The study focuses on the electrocarboxylation of 1,3,3-trimethylindolino-6'-bromobenzopyrylospiran switch (Br-BIPS). Prior to the electrocarboxylation process, the electrochemical reduction mechanism of Br-BIPS and CO 2 is disclosed in polar aprotic solvents using two different cathodes (glassy carbon and silver) under nitrogen atmosphere. Once the role of the cathode in the reduction carbon-bromide bond cleavage is understood, carboxylated spiropyran derivatives can be synthesized in moderate yields and conversion rates through an electrocarboxylation process using CO 2 silver cathode and polar aprotic solvents. The "green" efficient route described in the current work would open a new sustainable strategy for designing and building "smart" surfaces with switchable physical properties.