Steady-state absorption and fluorescence spectra, and time-resolved fluorescence spectra of coumarin 343 （C343） were measured in different solvents. The effect of the solvent on the spectral properties and dipole mo...Steady-state absorption and fluorescence spectra, and time-resolved fluorescence spectra of coumarin 343 （C343） were measured in different solvents. The effect of the solvent on the spectral properties and dipole moment of the lowest excited state of C343 were investigated. It was found that the absorption and fluorescence spectra red-shifted slightly and strongly with increasing solvent polarity, respectively, because the charge distribution of the excited state leaded to the increasing difference between the absorption and fluorescence spectra with increasing solvent polarity. The dipole moment of the lowest excited state of C343 was determined from solvatochromic measurements and the quantum chemical calculation, and the results obtained from these two methods were fully consistent. Investigations of the time-resolved fluorescence of C343 in different solvents indicated that the fluorescence lifetimes increased nearly linearly with 4.45 ns in water. This can be ascribed between C343 and hydrogen donating increasing solvent polarity from 3.09 ns in toluene to to the intermolecular hydrogen bonding interactions solvents展开更多
As global climate change intensifies,the concentration of carbon dioxide(CO_(2))in the atmosphere keeps rising,and reducing CO_(2) emissions while realizing its resource utilization has become key to achieving the“ca...As global climate change intensifies,the concentration of carbon dioxide(CO_(2))in the atmosphere keeps rising,and reducing CO_(2) emissions while realizing its resource utilization has become key to achieving the“carbon peaking”and“carbon neutrality”goals.Catalytic conversion of CO_(2) into high-value C1 compounds(such as formic acid,methanol,and methane)is a very promising approach.However,the traditional stepwise“capture-desorption-conversion”process,while technically relatively mature,has poor economic feasibility because it requires energy-intensive desorption and compression steps.To address this issue,researchers have developed the strategy of“CO_(2) capture and in situ hydrogenation conversion”which first uses solvents(inorganic alkalis,organic alkaline solvents,and ionic liquids)to capture gaseous CO_(2) and then directly hydrogenates the captured CO_(2) in the solvent,eliminating the energy-intensive desorption process and thus reducing the energy consumption and costs of the entire process.This review systematically summarizes the latest research progress in the CO_(2) capture-coupled in situ hydrogenation technology,focuses on discussing the performance of CO_(2) hydrogenation in C1 chemical synthesis,and explains their reaction mechanisms;additionally,it takes an in-depth look at the multiple roles of solvents including the capture and activation of CO_(2),regulation of reaction equilibrium,stabilization of key intermediates,solvation effects,and dispersion and stabilization of catalysts.Finally,this review outlines the future challenges and development directions of this technology such as the development of new catalytic and solvent systems and process integration,aiming to provide valuable references for promoting the practical application of this green and low-carbon technology.展开更多
文摘Steady-state absorption and fluorescence spectra, and time-resolved fluorescence spectra of coumarin 343 （C343） were measured in different solvents. The effect of the solvent on the spectral properties and dipole moment of the lowest excited state of C343 were investigated. It was found that the absorption and fluorescence spectra red-shifted slightly and strongly with increasing solvent polarity, respectively, because the charge distribution of the excited state leaded to the increasing difference between the absorption and fluorescence spectra with increasing solvent polarity. The dipole moment of the lowest excited state of C343 was determined from solvatochromic measurements and the quantum chemical calculation, and the results obtained from these two methods were fully consistent. Investigations of the time-resolved fluorescence of C343 in different solvents indicated that the fluorescence lifetimes increased nearly linearly with 4.45 ns in water. This can be ascribed between C343 and hydrogen donating increasing solvent polarity from 3.09 ns in toluene to to the intermolecular hydrogen bonding interactions solvents
基金supported by the National Natural Science Foundation of China(Grants 21176020 and 21306007).
文摘As global climate change intensifies,the concentration of carbon dioxide(CO_(2))in the atmosphere keeps rising,and reducing CO_(2) emissions while realizing its resource utilization has become key to achieving the“carbon peaking”and“carbon neutrality”goals.Catalytic conversion of CO_(2) into high-value C1 compounds(such as formic acid,methanol,and methane)is a very promising approach.However,the traditional stepwise“capture-desorption-conversion”process,while technically relatively mature,has poor economic feasibility because it requires energy-intensive desorption and compression steps.To address this issue,researchers have developed the strategy of“CO_(2) capture and in situ hydrogenation conversion”which first uses solvents(inorganic alkalis,organic alkaline solvents,and ionic liquids)to capture gaseous CO_(2) and then directly hydrogenates the captured CO_(2) in the solvent,eliminating the energy-intensive desorption process and thus reducing the energy consumption and costs of the entire process.This review systematically summarizes the latest research progress in the CO_(2) capture-coupled in situ hydrogenation technology,focuses on discussing the performance of CO_(2) hydrogenation in C1 chemical synthesis,and explains their reaction mechanisms;additionally,it takes an in-depth look at the multiple roles of solvents including the capture and activation of CO_(2),regulation of reaction equilibrium,stabilization of key intermediates,solvation effects,and dispersion and stabilization of catalysts.Finally,this review outlines the future challenges and development directions of this technology such as the development of new catalytic and solvent systems and process integration,aiming to provide valuable references for promoting the practical application of this green and low-carbon technology.
