Spectra and relaxation dynamics of the pseudohalide (PS) vibrational bands for Ru(bpy)2(PS)2 complexes, PS=CN, NCS and N3

Boosting nucleophilic attack to realize high current density biomass valorization on a tunable Prussian blue analogue

Electrochemical biomass valorization provides a promising approach to generating value-added chemicals. Herein, we have creatively utilized a Prussian blue analogue as a structure template of the anodic catalyst and improved its catalyst capacity by adjusting its electronic structure. The nickel-based Prussian blue analogue/Ni foam (NiFe-PBA/NF) exhibits excellent performance for methanol (MeOH) oxidation and achieves almost 94.1% FE of formic acid at a high current density of 500 mA cm-2. Apart from formic acid, NiFe-PBA/NF also has good catalytic ability for ethanol, glycerol, glucose, and 5-hydroxymethylfurfural (HMF). In short, this work has developed a promising class of catalysts for biomass valorization.

Non-innocent ligand flavone and curcumin inspired ruthenium photosensitizers for solar energy conversion

A series of ruthenium photosensitizers incorporating a β-diketonate non-innocent ligand were synthesized, characterized, and implemented in dye-sensitized solar cells. Electrochemical studies exhibited well behaved reversible oxidations and reductions for all β-diketonate complexes. The acac- and Ph2acac- based photosensitizers possess limited delocalization across the ligand π*-manifold, which is significant for exhibition of respectable power conversion efficiencies in a dye-sensitized solar cell (DSC) device. As the π-orbital network was extended on the flavone and curcumin inspired NILs, increased molar absorptivity was observed, however this ultimately proved detrimental to DSC performance consistent with exhibition of negligible photocurrent.

Short-lived intermediates in photochemistry of an OsCl62− complex in aqueous solutions

Photoaquation of an Os^IVCl₆²⁻ complex occurs via a pentacoordinated Os^IVCl₅⁻ intermediate.

Primary photophysical and photochemical processes for hexachloroosmate(iv) in aqueous solution

The photoaquation of the Os^IVCl₆^2- complex was studied by means of stationary photolysis, nanosecond laser flash photolysis and ultrafast kinetic spectroscopy. The Os^IVCl₅(OH)^2- complex was found to be the only reaction product. The quantum yield of photoaquation is rather low and wavelength-dependent. No impact of redox processes on photoaquation was revealed. The total characteristic lifetime of the process is about 80 ps. Three intermediates were recorded in the femto- and picosecond time domains and assigned to different Os(iv) species. The nature of intermediates and possible mechanisms of photoaquation are discussed.

Spectroscopic signatures of ligand field states in {Ru(II)(imine)} complexes

Ligand field (LF) states have been present in discussions on the photophysics and photochemistry of ruthenium-iminic chromophores for decades, although there is very little documented direct evidence of them. We studied the picosecond transient absorption (TA) spectroscopy of four {Ru(II)(imine)} complexes that respond to the formula trans-[Ru(L)4(X)2], where L is either pyridine (py) or 4-methoxypyridine (MeOpy) and X is either cyanide or thiocyanate. Dicyano compounds behave as most ruthenium polypyridines and their LF states remain silent. In contrast, in the dithiocyanate complexes we found clear spectroscopic evidence of the participation of LF states in the MLCT decay pathway. These states are of donor and acceptor character simultaneously and this is manifested in the presence of MLCT and LMCT transient absorption bands of similar energy. Spectroelectrochemical techniques supported the interpretation of the absorption features of MLCT states, and DFT methods helped to assign their spectroscopic signatures and provided strong evidence on the nature of LF states.