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Here we report on the fabrication of a new low-cost transparent cathode based on platinum nanoparticles prepared by a bottom-up synthetic approach. Scanning Electron Microscope (SEM) images showed the platinum nanoparticles homogeneously distributed on a fluorine doped tin oxide conductive glass surface. We demonstrated that, with such a type of cathode, the solar energy conversion efficiency is the same as that obtained with a platinum sputtered counter-electrode, and is more than 50% greater than that obtained with a standard electrode, i.e. one prepared by chlorine platinum acid thermal decomposition, in similar working conditions. Using a special back-reflecting layer of silver, we improved upon the performance of a counter-electrode based on platinum sputtering, achieving an overall solar conversion efficiency of 4.75% at 100 mW cm À2 (AM 1.5) of simulated sunlight.

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Seven flavylium salt dyes were employed for the first time as sensitizers for dye-sensitized solar cells (DSSCs). The theoretical and experimental wavelengths of the maximum absorbances, the HOMO and LUMO energy levels, the coefficients, the oscillator strengths and the dipole moments are calculated for these synthetic dyes. The introduction of a donor group in the flavylium molecular structure was investigated. Photophysical and photoelectrochemical measurements showed that some of these synthetic analogues of anthocyanins are very promising for DSSC applications. The best performance was obtained by a DSSC based on the novel compound 7-(N,N-diethylamino)-3',4'-dihydroxyflavylium which produced a 2.15% solar energy-to-electricity conversion efficiency, under AM 1.5 irradiation (100 mW cm(-2)) with a short-circuit current density (J(sc)) of 12.0 mA cm(-2), a fill factor of 0.5 and an open-circuit voltage (V(oc)) of 0.355 V; its incident photocurrent efficiency of 51% at the peak of the visible absorption band of the dye is remarkable. Our results demonstrated that the substitution of a hydroxylic group with a diethylamine unit in position 7 of ring A of the flavylium backbone expanded the π-conjugation in the dye and thus resulted in a higher absorption in the visible region and is advantageous for effective electron injection from the dye into the conduction band of TiO2.

Amylin is the 37-residue peptide hormone produced by the islet β-cells in the pancreas and the formation of amylin aggregates is strongly associated with β-cells degeneration in type 2 diabetes, as demonstrated by more than 95% of patients exhibiting amylin amyloid upon autopsy.It is widely recognized that metal ions such as copper(II) have been implicated in the aggregation process of amyloidogenic peptides such as Aβ and α-synuclein and there is evidence that also amylin self-assembly is largely affected by copper(II). For this reason, in this work, the role of copper(II) in the aggregation of amylin has been investigated by several different experimental approaches. Mass spectrometric investigations show that copper(II) induces significant changes in the amylin structure which decrease the protein fibrillogenesis as observed by ThT measurements. Accordingly, solid-state NMR experiments together with computational analysis carried out on a model amylin fragment confirmed the non fibrillogenic nature of the copper(II) induced aggregated structure. Finally, the presence of copper(II) is also shown to have a major influence on amylin proneness to be degraded by proteases and cytotoxicity studies on different cell cultures are reported.4

The copper-catalysed cycloaddition of alkynes and azides to form 1,2,3-triazoles has emerged as a powerful tool in ligand design and the synthesis of novel transition metal complexes. In this review we focus on the photophysical properties of metal complexes bearing 1,2,3-triazole-based ligands with a particular emphasis on those of d 6 metals including rhenium(I), iron(II), ruthenium(II), osmium(II) and iridium(III). We also highlight key examples of triazole complexes of platinum(II) and palladium(II) as well as the lanthanides and coinage metals. 1. Introduction 2. Photophysical properties of d 6 metal triazole-based complexes 2.1 Rhenium(I) complexes 2.2 Iridium(III) complexes 2.3 Ruthenium(II) complexes 2.4 Iron(II) complexes 2.5 Osmium(II) complexes 2.6 Photochemistry of 1,2,3-triazole-based d 6 metal complexes 3. Platinum(II) and palladium(II) complexes 4. Coinage metal complexes 5. Lanthanide complexes 6. Triazole-based sensors for metal ions 7. Conclusions & outlook.

We report the unprecedented observation and unequivocal crystallographic characterization of the meta-stable ligand loss intermediate solvento complex trans-[Ru(bpy)(κ2-btz)(κ1-btz)(NCMe)]2+ (1 a) that contains a monodentate chelate ligand. This and analogous complexes can be observed during the photolysis reactions of a family of complexes of the form [Ru()(btz)2]2+ (1 a–d: btz=1,1′-dibenzyl-4,4′-bi-1,2,3-triazolyl; =a) 2,2′-bipyridyl (bpy), b) 4,4′-dimethyl-2,2′-bipyridyl (dmbpy), c) 4,4′-dimethoxy-2,2′-bipyridyl (dmeobpy), d) 1,10-phenanthroline (phen)). In acetonitrile solutions, 1 a–d eventually convert to the bis-solvento complexes trans-[Ru()(btz)(NCMe)2]2+ (3 a–d) along with one equivalent of free btz, in a process in which the remaining coordinated bidentate ligands undergo a new rearrangement such that they become coplanar. X-ray crystal structure of 3 a and 3 d confirmed the co-planar arrangement of the and btz ligands and the trans coordination of two solvent molecules. These conversions proceed via the observed intermediate complexes 2 a–d, which are formed quantitatively from 1 a–d in a matter of minutes and to which they slowly revert back on being left to stand in the dark over several days. The remarkably long lifetime of the intermediate complexes (>12 h at 40 °C) allowed the isolation of 2 a in the solid state, and the complex to be crystallographically characterized. Similarly to the structures adopted by complexes 3 a and d, the bpy and κ2-btz ligands in 2 a coordinate in a square-planar fashion with the second monodentate btz ligand coordinated trans to an acetonitrile ligand.

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