Correlating photochemical H production and excited state lifetimes of heterostructured and doped ZnCdS nanoparticles.

A variety of ZnCdS-based semiconductor nanoparticle heterostructures with extended exciton lifetimes were synthesized to enhance the efficacy of photocatalytic hydrogen production in water. Specifically, doped nanoparticles (NPs), as well as core/shell NPs with and without palladium and platinum co-catalysts, were solubilized into water using various methods to assess their efficacy for solar H fuel synthesis. The best results were obtained with low bandgap ZnCdS cores and ZnCdS/ZnS core/shell NPs with palladium co-catalysts.

Heavy atom effects on synthetic pyranoanthocyanin analogues.

Pyranoflavylium cations are synthetic analogues of pyranoanthocyanins, the much more color-stable compounds that are formed spontaneously from grape anthocyanins during the maturation of red wines. In the present work, our studies of the photophysical properties of pyranoanthocyanin analogues are extended to include nine pyranoflavylium cations substituted with one or two bromo and/or iodo heavy atoms. The room temperature fluorescence, 77 K fluorescence and phosphorescence, triplet formation in solution, and sensitized singlet oxygen formation, with excited state acidity suppressed by the addition of trifluoroacetic acid, are compared to those of similar pyranoflavylium cations that do not contain a heavy atom.

Targeted Modulation of Photocatalytic Hydrogen Evolution Activity by Nickel-Substituted Rubredoxin through Functionalized Ruthenium Phototriggers.

Light-driven hydrogen evolution is a promising means of sustainable energy production to meet global energy demand. This study investigates the photocatalytic hydrogen evolution activity of nickel-substituted rubredoxin (NiRd), an artificial hydrogenase mimic, covalently attached to a ruthenium phototrigger (RuNiRd). By systematically modifying the para-substituents on Ru(II) polypyridyl complexes, we sought to optimize the intramolecular electron transfer processes within the RuNiRd system.

Photo- and Electrocatalytic Hydrogen Evolution by Heteroleptic Dirhodium(II,II) Complexes: Role of the Bridging and Diimine Ligands.

A series of heteroleptic Rh(II,II) complexes, [Rh(μ-DPhF)(μ-bncn)] (; bncn = benzo[]cinnoline), [Rh(μ-DPhF)(μ-OAc)(μ-bncn)] (), and [Rh(μ-OAc)(μ-bncn)] (), is presented, and the excited state and redox properties of each complex was characterized for the photo- and electrocatalytic production of H. The oxidation potentials shift anodically from to , consistent with a highest occupied molecular orbital (HOMO) with significant metal-ligand mixing, Rh(δ*)/DPhF(π/nb). In contrast, modest differences in the first two bncn-localized reversible reduction potentials were observed in - .

Mixed Ru(II)-Ir(III) Complexes as Photoactive Inhibitors of the Major Human Drug Metabolizing Enzyme CYP3A4.

Cytochrome P450 3A4 (CYP3A4) is a crucial enzyme in human drug metabolism. To garner photochemical control over the inhibition of CYP3A4, a potent Ir(III)-based inhibitor of CYP3A4 was complexed with two Ru(II)-based photocaging groups. Chemical, photochemical, and biological properties of the photocaged inhibitors were characterized.