Equilibrium photoproduct of 7r-cyclopentadienyliron dicarbonyl dimer [CpFe（CO）2]2 in non- polar solvent carbon tetrachloride （CC14） is investigated using time-resolved 2D IR spec- troscopy. One of the several poss...Equilibrium photoproduct of 7r-cyclopentadienyliron dicarbonyl dimer [CpFe（CO）2]2 in non- polar solvent carbon tetrachloride （CC14） is investigated using time-resolved 2D IR spec- troscopy. One of the several possible visible-light-driven photoreaction pathways is confirmed and the product is found to contain a di-carbonyl group that exhibits quantum beating be- tween two equivalent transitions in time-resolved 2D IR spectra, which turns out to be the anti-symmetric and symmetric stretching of the terminal carbonyl stretching modes of CpFe（CO）2C1. This is the main product and its reaction pathway involves radical formation, followed by chloride addition. Quantum-chemistry computations support these experimental results. Our results indicate that 2D IR method can be used to identify in situ structures and dynamics of chemical species involved in condensed-phase chemical reactions.展开更多
Despite the intense research efforts directed to electrocatalytic nitrogen reduction reaction(eNRR),the NH_(3) yield and selectivity are still not up to the standard of practical application.Here,high-entropy perovski...Despite the intense research efforts directed to electrocatalytic nitrogen reduction reaction(eNRR),the NH_(3) yield and selectivity are still not up to the standard of practical application.Here,high-entropy perovskite oxides with composition Bax(FeCoNiZrY)_(0.2)O_(3−δ)(Bx(FCNZY)_(0.2)(x=0.9,1)are reported as eNRR catalysts.The eNRR activity of high-entropy perovskite oxide is enhanced by changing the nonstoichiometric metal elements at the A-site,thus generating additional oxygen vacancies.The NH_(3) yield and Faraday efficiency for B_(0.9)(FCNZY)_(0.2) are 1.51 and 1.95 times higher than those for B(FCNZY)_(0.2),respectively.The d-band center theory is used to theoretically predict the catalytically active center at the B-site,and as a result,nickel was identified as the catalytic site.The free energy values of the intermediate states in the optimal distal pathway show that the third protonation step(*NNH_(2)→*NNH_(3))is the rate-determining step and that the increase in oxygen vacancies in the high-entropy perovskite contributes to nitrogen adsorption and reduction.This work provides a framework for applying high-entropy structures with active site diversity for electrocatalytic nitrogen fixation.展开更多
Electrochemistry contributes a strong tool for the manufacture of molecules,addressing intractable challenges in synthetic chemistry by enabling innovative reaction pathways.Herein,a bifunctional reagent,aqueous hydro...Electrochemistry contributes a strong tool for the manufacture of molecules,addressing intractable challenges in synthetic chemistry by enabling innovative reaction pathways.Herein,a bifunctional reagent,aqueous hydrochloric acid,is used to establish an electrochemical selective dual-oxidation approach that gives access toα-chlorosulfoxides from sulfides.This strategy presents broad substrate scope,high diastereoselectivity,and regioselectivity.The late-stage modification of amino acids and pharmaceutical derivatives further highlights the utility.Furthermore,detailed mechanistic studies reveal that the key success for this selective chemical transformation is the dual-oxidation process at the anode.This electrochemical dual-oxidation strategy may have wide universality;we anticipate diverse applications of this protocol across the many fields of chemistry.展开更多
文摘Equilibrium photoproduct of 7r-cyclopentadienyliron dicarbonyl dimer [CpFe（CO）2]2 in non- polar solvent carbon tetrachloride （CC14） is investigated using time-resolved 2D IR spec- troscopy. One of the several possible visible-light-driven photoreaction pathways is confirmed and the product is found to contain a di-carbonyl group that exhibits quantum beating be- tween two equivalent transitions in time-resolved 2D IR spectra, which turns out to be the anti-symmetric and symmetric stretching of the terminal carbonyl stretching modes of CpFe（CO）2C1. This is the main product and its reaction pathway involves radical formation, followed by chloride addition. Quantum-chemistry computations support these experimental results. Our results indicate that 2D IR method can be used to identify in situ structures and dynamics of chemical species involved in condensed-phase chemical reactions.
基金supported by the National Natural Science Foundation of China (52161135302, 21674019, and 51801075)the Research Foundation Flanders (G0F2322N)+8 种基金Shanghai Scientific and Technological Innovation Project (18JC1410600)the Program of the Shanghai Academic Research Leader (17XD1400100)the financial support from the Flemish Government through the Moonshot cSBO project P2C (HBC.2019.0108)the Long-term Structural Funding (Methusalem CASAS2, Meth/15/04)Interne Fondsen KU Leuven through project C3/20/067the support from the Research Foundation-Flanders (FWO) in the form of a doctoral fellowship (1SA3321N)the financial support from China Scholarship Council in the form of a visiting Ph.D. Student (File No. 202106790090)the LvLiang Cloud Computing Center of China, and the calculations were performed on a TianHe-2 systemthe characterizations supported by the Central Laboratory, School of Chemical and Material Engineering, Jiangnan University。
文摘Despite the intense research efforts directed to electrocatalytic nitrogen reduction reaction(eNRR),the NH_(3) yield and selectivity are still not up to the standard of practical application.Here,high-entropy perovskite oxides with composition Bax(FeCoNiZrY)_(0.2)O_(3−δ)(Bx(FCNZY)_(0.2)(x=0.9,1)are reported as eNRR catalysts.The eNRR activity of high-entropy perovskite oxide is enhanced by changing the nonstoichiometric metal elements at the A-site,thus generating additional oxygen vacancies.The NH_(3) yield and Faraday efficiency for B_(0.9)(FCNZY)_(0.2) are 1.51 and 1.95 times higher than those for B(FCNZY)_(0.2),respectively.The d-band center theory is used to theoretically predict the catalytically active center at the B-site,and as a result,nickel was identified as the catalytic site.The free energy values of the intermediate states in the optimal distal pathway show that the third protonation step(*NNH_(2)→*NNH_(3))is the rate-determining step and that the increase in oxygen vacancies in the high-entropy perovskite contributes to nitrogen adsorption and reduction.This work provides a framework for applying high-entropy structures with active site diversity for electrocatalytic nitrogen fixation.
基金supported by the National Natural Science Foundation of China(22031008)Science Foundation of Wuhan(2020010601012192)The Program of Introducing Talents of Discipline to Universities of China(111 Program)is also appreciated。
文摘Electrochemistry contributes a strong tool for the manufacture of molecules,addressing intractable challenges in synthetic chemistry by enabling innovative reaction pathways.Herein,a bifunctional reagent,aqueous hydrochloric acid,is used to establish an electrochemical selective dual-oxidation approach that gives access toα-chlorosulfoxides from sulfides.This strategy presents broad substrate scope,high diastereoselectivity,and regioselectivity.The late-stage modification of amino acids and pharmaceutical derivatives further highlights the utility.Furthermore,detailed mechanistic studies reveal that the key success for this selective chemical transformation is the dual-oxidation process at the anode.This electrochemical dual-oxidation strategy may have wide universality;we anticipate diverse applications of this protocol across the many fields of chemistry.
