Ancillary Ligand Effects on Heteroleptic Ir Dye in Dye-Sensitized Photocatalytic CO Reduction: Photoaccumulation of Charges on Arylated Bipyridine Ligand and Its Control on Catalytic Performance.

Herein, we report the synthesis, and photochemical and -physical properties, as well as the catalytic performance, of a series of heteroleptic Ir photosensitizers (IrPSs), [Ir(C^N) (N^N )] , possessing ancillary ligands that are varied with aryl-substituents on bipyridyl unit [C^N=(2-pyridyl)benzo[b]thiophen-3-yl (btp); N^N =4,4'-Y -bpy (Y=-Ph or -PhSi(Ph) ]. We found that the π-extension of bipyridyl ligand by aryl-substitution put bipyridyl ligand in use as an electron relay unit that performed charge accumulation before delivering to the catalytic center, greatly improving the overall CO -to-CO conversion activities. In a typical run, the aryl-substituted IrPS ( IrP-Ph )-sensitized homogeneous systems (IrPS+Re catalyst) gave a turnover number of 1340 (Φ =24.

Utility of Squaraine Dyes for Dye-Sensitized Photocatalysis on Water or Carbon Dioxide Reduction.

Red light-sensitized squaraine () dyes were developed and incorporated into dye-sensitized catalysts (DSCs) with the formula of /TiO/Cat, and their efficacies were evaluated in terms of performance on either water or carbon dioxide reduction. Pt nanoparticles or -[Re(4,4'-bis-(diethoxyphosphorylmethyl)-2,2'-bipyridine)(CO)Cl] were used as each catalytic center within the DSC frame of /TiO/Pt (Type I) or /TiO/Re(I) (Type II). In order to convey the potential utility of in low energy sensitization, the following catalytic reductions were carried out under selective lower energy irradiation (>500 nm).

Organometallic Iridium(III) Complex Sensitized Ternary Hybrid Photocatalyst for CO to CO Conversion.

A series of heteroleptic iridium(III) complexes functionalized with two phosphonic acid (-PO H ) groups ( IrP, IrP, IrP, and IrP) were prepared and anchored onto rhenium(I) catalyst (ReP)-loaded TiO particles (TiO /ReP) to build up a new IrP-sensitized TiO photocatalyst system (IrP/TiO /ReP). The photosensitizing behavior of the IrP series was examined within the IrP/TiO /ReP platform for the photocatalytic conversion of CO into CO. The four IrP-based ternary hybrids showed increased conversion activity and durability than that of the corresponding homo- (IrP+ReP) and heterogeneous (IrP+TiO /ReP) mixed systems.