Spectrum Correction in Study of Solvation Dynamics by Fluorescence Non-collinear Optical Parametric Amplification Spectroscopy

Femtosecond time-resolved fluorescence non-collinear optical parametric amplification spec- troscopy can extract the curve of spectral gain from its parametric superfluorescence. This unique spectrum correction method enables fluorescence non-collinear optical parametric amplification spectroscopy acquiring the genuine transient fluorescence spectrum of the studied system. In this work we employ fluorescence non-collinear optical parametric amplification spectroscopy technique to study the solvation dynamics of DCM dye in ethanol solution, and confirm that genuine solvation correlation function and shift of peak frequency can be derived from transient fluorescence spectra after the spectral gain correction. It demonstrates that fluorescence non-collinear optical parametric amplification spectroscopy can benefit the research fields, which focuses on both fluorescence intensity dynamics and fluorescence spectral shape evolution.

Visible light-driven oxygen evolution using a binuclear Ru-bda catalyst

Binuclear ruthenium complexes bearing the2,2'‐bipyridine‐6,6'‐dicarboxylate(bda)ligand have been demonstrated to be highly active catalysts towards water oxidation with CeIV as an oxidant.However,the catalytic properties of ruthenium dimers have not yet been explored for visible light‐driven water oxidation.Herein,the photocatalytic performance of a dipyridyl propane‐bridged ruthenium dimer2was investigated in comparison with its monomeric precursor,[Ru(bda)(pic)2](1),in CH3CN/phosphate buffer mixed solvent in a three‐component system including a photosensitizer and a sacrificial electron acceptor.Experimental results showed that the activity of each catalyst was strongly dependent on the content of CH3CN in the phosphate buffer,which not only affected the driving force for water oxidation,but also altered the kinetics of the reaction,probably through different mechanisms associated with the O–O bond formation.As a result,dimer2showedsignificantly higher activity than monomer1in the solvent containing a low content of CH3CN,and comparable activities were attained with a high content of CH3CN in the solvent.Under the optimal conditions,complex2achieved a turnover number of638for photocatalytic O2evolution.

Kinetics of Glucose Ethanolysis Catalyzed by Extremely Low Sulfuric Acid in Ethanol Medium

The kinetics for production of ethyl levulinate from glucose in ethanol medium was investigated. The experiments were performed in various temperatures （433-473 K） and initial glucose concentrations （0.056-0.168 mol·L-1） with extremely low sulfuric acid as the catalyst. The results show that higher temperature can improve the conversion of glucose to ethyl levulinate, with higher yield of ethyl levulinate （44.79%, by mole） obtained at 473 K for 210 min. The kinetics follows a simplified first-order kinetic model. For the main and side reactions, the values of activation energy are 122.64 and 70.97 kJ·mo1-1, and the reaction orders are 0.985 and 0.998, respectively.

Solvation structure and dynamics of Li and LiO_(2)and their transformation in non-aqueous organic electrolyte solvents from first-principles simulations

Density functional theory calculations together with ab initio molecular dynamics(AIMD)simulations have been used to study the solvation,diffusion and transformation of Li^(+)and LiO_(2)upon O_(2)reduction in three organic electrolytes.These processes are critical for the performance of Li-air batteries.Apart from studying the structure of the solvation shells in detail,AIMD simulations have been used to derive the diffusivity and together with the Blue Moon ensemble approach to explore LiO_(2)formation from Li^(+)and O_(2)−and the subsequent disproportionation of 2LiO_(2)into Li_(2)O_(2)+O_(2).By comparing the results of the simulations to gas phase calculations,the impact of electrolytes on these reactions is assessed which turns out to be more pronounced for the ionic species involved in these reactions.