Currently,simultaneous regulation of external morphology and internal electronic structure for Na_(3)V_(2)(PO_(4))_(3)(NVP)is rarely realized.Herein,complexes of β-cyclodextrin(βCD)and ethylenediaminetetraacetic aci...Currently,simultaneous regulation of external morphology and internal electronic structure for Na_(3)V_(2)(PO_(4))_(3)(NVP)is rarely realized.Herein,complexes of β-cyclodextrin(βCD)and ethylenediaminetetraacetic acid ferric sodium salt(EDTAFeNa)are utilized for the one-step preparation of NVP with spherical morphology as well as Fe substitution.βCD is initially hydrolyzed into glucose,and then carbon microspheres with numerous pores are formed through continuous dehydration and carbonization.The intermediate hydroxymethylfurfural is rich in active functional groups,which are attractive for the V/P-contained raw materials.Accordingly,the nucleation sites for NVP are successfully limited in the spherical framework,possessing a superior surface area of 97.15 g m^(-2).Furthermore,the beneficial Fe in EDTAFeNa enters into the NVP bulk to construct a novel Fe-doped Na_(3)V_(1.95)Fe_(0.05)(PO_(4))_(3)(NVP/β-ISC)material.Fe-substitution induces significant optimizations of electronic structure for NVP,which has been verified by the newly generated abundant oxygen vacancies and extended V-O bond length.Moreover,a multielectron reaction is activated,resulting from the V^(4+)/V^(5+)redox couple.The charge compensation mechanism of NVP/β-ISC is also deeply investigated.Density functional theory(DFT)calculations theoretically elaborate the mechanism of Fe-doping.Consequently,NVP/β-ISC reveals superior sodium storage performance in both half and full cells and even at different extreme conditions(needling,soaking,bending,and freezing).展开更多
The field-ionization Coulomb explosion model is extended to investigate the multielectron dissociative ionization process of N2 molecule irradiated by an intense femtosecond laser field with an arbitrary polarization....The field-ionization Coulomb explosion model is extended to investigate the multielectron dissociative ionization process of N2 molecule irradiated by an intense femtosecond laser field with an arbitrary polarization. The ionization process of N2 molecule is found to be optimal at the critical internuclear distance Rc=7a.u., which is independent of the laser polarization state, the molecular explosion channel and the angle between the molecular axis and the direction of laser electric field. The kinetic energies of the ion fragments are identical in the cases of linear and circular polarizations at the same incident laser intensity. However, the probability of electron ionization is very sensitive to the above three parameters. At the critical distance Rc=7a.u. the angular dependence of the threshold intensity for the over-the-barrier ionization leads to the geometric alignment of molecules in the case of linear polarization. The threshold intensity in the case of circular polarization is apparently higher than that in the case of linear polarization, which can well explain the significant decrease of ionization in the case of circular polarization. The numerical calculations are compared with the experimental measurements.展开更多
Gold and atomically precise polyoxometalates(POMs)are widely used materials with electron reservoir redox properties.The combination of optically excited gold nanoparticles,gold surface/tip electrodes,or molecular gol...Gold and atomically precise polyoxometalates(POMs)are widely used materials with electron reservoir redox properties.The combination of optically excited gold nanoparticles,gold surface/tip electrodes,or molecular gold(I)complexes with{V_(6)^(V)}Lindqvist-,{MnMo_(6)^(VI)}Anderson-Evans-,and{PW_(12)^(VI)}Keggin-type POM structures leads to interfacial multielectron transformations with far-reaching implications for electronics,photonics,biomedical diagnostics,and catalysis.展开更多
The introduction of redox-active ligands into transition metal complexes can lead to novel redox behavior due to the ability of these ligands to serve as electron reservoirs.This feature is especially attractive in ea...The introduction of redox-active ligands into transition metal complexes can lead to novel redox behavior due to the ability of these ligands to serve as electron reservoirs.This feature is especially attractive in earth-abundant transition metal systems that typically favor one-electron redox processes and radical reactivity,as opposed to the two-electron redox cycles common with the noble metals.The redox flexibility afforded by redox-active ligands can enable substrate activation and/or bond forming and breaking processes that would otherwise be inaccessible with traditional redox-innocent ligands.This review discusses key examples of stoichiometric substrate activation and organic transformations facilitated by redox-active ligand-promoted multielectron reactivity at earth-abundant metal complexes.We highlight the electrochemical properties of these systems in relation to their substrate reactivity,where,in many cases,the complexes exhibit sequential one-electron redox events.Only a few examples have achieved electrocatalytic reactivity based on two-electron redox features,which underscores the untapped potential for further development of redox-active ligand systems to expand the capabilities of earth-abundant metal complexes in electrocatalysis.展开更多
In most cases,the redox activity of a U^(Ⅵ)O_(2)^(2+) complex is regarded as metal-centered phenomena,because uranium has small energy gaps amongst the 5f/6d/7s subshells,thereby exhibiting a wide range of oxidation ...In most cases,the redox activity of a U^(Ⅵ)O_(2)^(2+) complex is regarded as metal-centered phenomena,because uranium has small energy gaps amongst the 5f/6d/7s subshells,thereby exhibiting a wide range of oxidation states,commonly from+Ⅲ to+Ⅵ or in some cases even+I or+Ⅱ.While a wide variety of redox-active ligands are known for use as transition metal complexes including multi-electron reduction that could facilitate inert bond or small molecule activation,only a few such examples are known for U^(Ⅵ)O_(2)^(2+).In this study,three U^(Ⅵ)O_(2)^(2+)complexes bearing α-diimine-,o-quinonediimine-and 2,6-diiminopyridine-based ligands were synthesized,which exhibited two redox couples in the range of−0.79 V to−2.02 V vs.Fc+/0 to give singly-and doubly-reduced complexes by stepwise reduction.Unique electronic transitions of U^(Ⅵ)O_(2)^(2+) complexes with a variety of low-lying excited states helped us to combine spectroelectrochemistry and time-dependent density functional theory(TD-DFT)calculations which complemented each other to assign the redox-active site in these U^(Ⅵ)O_(2)^(2+) complexes,i.e.,whether or not a ligand of interest becomes redox-active.During all the redox processes observed here,the ligands employed are found to be exclusively redox-active,i.e.,non-innocent,whereas the centered U^(Ⅵ)O_(2)^(2+) is just“spectating”and remains unchanged,i.e.,innocent.Whereas the double reduction of the U^(Ⅵ)O_(2)^(2+) complexes usually involves breaking of strong UuO bonds,in the present examples this is not required and therefore a basis for the synthesis of new types of uranium molecular catalysts and magnetic materials may be found.展开更多
Designing and implementing multielectron transfer and single-molecule magnet properties in spin crossover compounds constitute a promising way to obtain a new class of multiresponsive and multifunctional materials.Thi...Designing and implementing multielectron transfer and single-molecule magnet properties in spin crossover compounds constitute a promising way to obtain a new class of multiresponsive and multifunctional materials.This contribution uses N-phenyl-substituted pyridine-2,6-diimine(PDI)ligands to explore a novel family of spin-crossover cobalt(Ⅱ)complexes,with general formula[CoL_(2)](ClO_(4))_(2)·xH_(2)O[L=4-MePhPDI(1,x=1),4-MeOPhPDI(2,x=0),4-MeSPhPDI(3,x=0),4-Me_(2)NPhPDI(4,x=0.5),and 2,4-Me_(2)PhPDI(5,x=0)].These mononuclear six-coordinate octahedral cobalt(Ⅱ)bis(chelating)complexes incorporate tridentate PDI derivatives with various electron-donating substituents at para(X_(4)=Me,OMe,SMe,and Me_(2)N)or ortho and para positions(X_(2),X_(4)=Me)of terminal phenyl rings.Our investigations reveal that these complexes exhibit both thermally-induced low-spin(LS)/high-spin(HS)transition and field-induced slow magnetic relaxation in the LS(S=1/2)and HS(S=3/2)states.Moreover,they display a dual multiredox behaviour featuring one-electron oxidation of the paramagnetic Co^(Ⅱ)ion to the diamagnetic Co^(Ⅲ)ion and stepwise two-electron reduction of each PDI ligand to the corresponding imine-type PDI·−π-radical anion and diimine-type PDI^(2−)dianion,which positions them as candidates for prototypes of spin quantum transistors and capacitors,offering potential applications in quantum information processing.展开更多
Novel benzo-bridged hexaphyrin(2.1.2.1.2.1)and its copper complex were synthesized.Single-crystal structures showed typical figure-of-eight Huckel topologies.NMR,NICS,HOMA,ACID,and EDDB analysis supported their non-ar...Novel benzo-bridged hexaphyrin(2.1.2.1.2.1)and its copper complex were synthesized.Single-crystal structures showed typical figure-of-eight Huckel topologies.NMR,NICS,HOMA,ACID,and EDDB analysis supported their non-aromatic properties owning to the strong local aromatic benzo rings cutting the global aromatic ring of the benzo-bridged figure-of-eight hexaphyrin(2.1.2.1.2.1).The redox properties and degenerate HOMOs and LUMOs levels indicate multielectron donating and accepting abilities.展开更多
Molecular high-order harmonic spectroscopy is a significant advancement in ultrafast science, enabling the measurement of multielectron dynamics with attosecond temporal resolution. The fine structures observed in the...Molecular high-order harmonic spectroscopy is a significant advancement in ultrafast science, enabling the measurement of multielectron dynamics with attosecond temporal resolution. The fine structures observed in the molecular harmonic spectrum provide crucial insights into the structural or multielectron dynamical effects induced by intense laser fields. In this study, we measure the high-order harmonic spectrum of aligned CO_(2) molecules contributed from short trajectories. Two distinct groups of minima are identified in the plateau region. Our findings indicate that the deeper-lying molecular orbitals and two-center interference play significant roles in molecular harmonic generation. The results pave the way for advancing the understanding of multielectron dynamics in polyatomic molecules under intense laser fields.展开更多
The capacity to predict X-ray transition and K-edge energies in dense finite-temperatur plasmas with high precision is of primary importance for atomic physics of matter under extreme conditions.The dual characteristi...The capacity to predict X-ray transition and K-edge energies in dense finite-temperatur plasmas with high precision is of primary importance for atomic physics of matter under extreme conditions.The dual characteristics of bound and continuum states in dense matter are modeled by a valence-band-like structure in a generalized ion-sphere approach with states that are either bound,free,or mixed.The self-consistent combination of this model with the Dirac wave equations of multielectron bound states allows one to fully respect the Pauli principle and to take into account the exact nonlocal exchange terms.The generalized method allows very high precision without implication of calibration shifts and scaling parameters and therefore has predictive power.This leads to new insights in the analysis of various data.The simple ionization model representing the K-edge is generalized to excitation–ionization phenomena resulting in an advanced interpretation of ionization depression data in near-solid-density plasmas.The model predicts scaling relations along the isoelectronic sequences and the existence of bound M-states that are in excellent agreement with experimental data,whereas other methods have failed.The application to unexplained data from compound materials also gives good agreement without the need to invoke any additional assumptions in the generalized model,whereas other methods have lacked consistency.展开更多
Cross sections of electron-loss in H（1s）＋ H（1s） collisions and total collisional destruction of H（2s） in H（1s） 4- H（2s） collisions are calculatted by four-body classical-trajectory Monte Caylo （CTMC） meth...Cross sections of electron-loss in H（1s）＋ H（1s） collisions and total collisional destruction of H（2s） in H（1s） 4- H（2s） collisions are calculatted by four-body classical-trajectory Monte Caylo （CTMC） method and compared with previous theoretical and experimental data over the energy range of 4-100 keV. For the former a good agreement is obtained within different four-body CTMC calculations, and for the incident energy Ep 〉 10 keV, comparison with the experimental data shows a better agreement than the results calculated by the impact parameter approx- imation. For the latter, our theory predicts the correct experimental behaviour, and the discrepancies between our results and experimental ones are less than 30%. Based on the successive comparison with experiments, the cross sections for excitation to H（2p）, single- and double-ionization and H- formation in H（2s）＋H（2s） collisions are calculated in the energy range of 4-100 keV for the first time, and compared with those in H（1s）＋H（1s） and H（1s）＋U（2s） collisions.展开更多
Developing suitable anode materials for potassium-ion batteries(PIBs)remains a great challenge owing to the limited theoretical capacity of active materials and large radius of K+ion(1.38?).To solve these obstacles,by...Developing suitable anode materials for potassium-ion batteries(PIBs)remains a great challenge owing to the limited theoretical capacity of active materials and large radius of K+ion(1.38?).To solve these obstacles,by integrating the principles of multielectron transfer and rational porous crystal framework,we creatively propose the monoclinic Cu_(3)(OH)_(2)V_(2)O_(7)·2H_(2)O(CVO)as a novel anode for PIBs.Furthermore,inspired by the metastable nature of CVO under high temperature/pressure,we skillfully design a facile hydrothermal recrystallization strategy without the phase change and surfactants addition.Thus,for the first time,the porous composite of Cu_(3)(OH)_(2)V_(2)O_(7)·2H_(2)O nanobelts covered in situ by reduced graphene oxide(CVO NBs/r GO)was assembled,greatly improving the deficiencies of CVO.When used as a novel anode for PIBs,CVO NBs/r GO delivers large specific capacity(up to 551.4 m Ah g^(-1)at 50 m A g^(-1)),high-rate capability(215.3 m Ah g^(-1)at 2.5 A g^(-1))and super durability(203.6 m Ah g^(-1)at 500 m A g^(-1)even after 1000 cycles).The outstanding performance can be ascribed to the synergistic merits of desirable structural features of monoclinic CVO nanobelts and the highly conductive graphene 3D network,thus promoting the composite material stability and electrical/ionic conductivity.This work reveals a novel metal vanadate-based anode material for PIBs,would further motivate the subsequent batteries research on M_(3)(OH)_(2)V_(2)O_(7)-n H_(2)O(M;Co,Ni,Cu,Zn),and ultimately expands valuable fundamental understanding on designing other high-performance electrode materials,including the combined strategies of multielectron transfer with rational porous crystal framework,and the composite fabrication of 1D electrode nanostructure with conductive carbon matrix.展开更多
Polyoxometalate-based metal–organic frameworks(POM-based MOFs)are extended structures that simultaneously possess the virtues of POMs and MOFs.They have been attracting immense attention because of their diverse arch...Polyoxometalate-based metal–organic frameworks(POM-based MOFs)are extended structures that simultaneously possess the virtues of POMs and MOFs.They have been attracting immense attention because of their diverse architectures and charming topologies,and also due to their probable application prospects in the areas of catalysis,sorption and separation,magnetism,proton conduction,lithium-ion batteries,supercapacitors,electrochemistry,medicine,and so on.In particular,the strong acidity,multielectron redox and photoactivity of POMs combined with the high surface area and adjustable pore size of MOFs make them excellent heterogeneous catalysts in various kinds of organic reactions.This short review firstly presents a concise introduction related to POMs,MOFs and POM-based MOFs,followed by the synthetic strategies of POM-based MOFs.The structural features and catalysis properties of representative POM-based MOFs have been classified and summarized according to different catalytic reactions,including acidity,oxidation,photocatalysis,electrocatalysis and other types of catalysis.The challenges present research situations,and prospects for the preparation and catalytic properties of POM-based MOFs are discussed.展开更多
Here we have explored the ability of Schiff bases to act as electron reservoirs and to enable the multielectron reduction of small molecules by lanthanide complexes.We report the reductive chemistry of the Ln_((III))c...Here we have explored the ability of Schiff bases to act as electron reservoirs and to enable the multielectron reduction of small molecules by lanthanide complexes.We report the reductive chemistry of the Ln_((III))complexes of the tripodal heptadentate Schiff base H_(3)trensal(2,2’,2’’-tris(salicylideneimino)triethylamine),[Ln_(III)(trensal)],1-Ln(Ln=Sm,Nd,Eu).We show that the reduction of the[Eu^(III)(trensal)]complex leads to the first example of a Eu^((II))Schiff base complex[{K(μ-THF)(THF)_(2)}_(2){EuII(trensal)}_(2)],3-Eu.In contrast the one-and two-electron reduction of the[NdIII(trensal)]and[SmIII(trensal)]leads to the intermolecular reductive coupling of the imino groups of the trensal ligand and to the formation of one and two C-C bonds leaving the metal center in the+3 oxidation state.The resulting one-and two electron reduced complexes[{K(THF)_(3)}_(2)Ln_(2)(bis-trensal)],2-Ln,and[{K(THF)_(3)}_(2){K(THF)}_(2)Ln_(2)(cyclo-trensal)],4-Ln(Ln=Sm,Nd)are able to effect the reductive disproportionation of carbon dioxide by transferring the electrons stored in the C-C bonds to CO_(2)to selectively afford carbonate and CO.The selectivity of the reaction contrasts with the formation of multiple CO_(2)reduction products previously reported for a U_((IV))-trensal system.展开更多
Polyoxometalates act as an electron sponge,processing multielectron redox reactions and acting as a fast ionic conductor.They show great potential as promising electrode materials for next-generation lithium ion batte...Polyoxometalates act as an electron sponge,processing multielectron redox reactions and acting as a fast ionic conductor.They show great potential as promising electrode materials for next-generation lithium ion batteries(LIBs).However,there are still some fundamental issues which should be solved before their application can be realized,such as determining the stable structural feature with reversible Li+ion insertion/desertion.In this work,polyoxovanadates(POVs)based materials of K_(4)Na_(2)V_(10)O_(28)·nH_(2)O(KNaV_(10))and Mg_(2)(NH_(4))2V_(10)O_(28)·nH_(2)O(MgV_(10))have been prepared and used as the electrode material for a Li+ion reservoir.The 10-core polyoxovanadate is demonstrated as a anionic building block and the 3D extended structure has been smartly tuned by counter cations.For MgV_(10),a 1D tunnel with an approximate size of 3Å×10Å was formed along the a axis by Mg^(2+)ions and[V_(10)O_(28)]^(6-)polyanions.The MgV_(10) shows a higher capacity,cycling stability,and rate performance than that of KNaV_(10) without tunnels.The capacity of MgV_(10) is about 160 mA h g^(-1) at a high discharge rate of 250 mA g^(-1),while it is only 118 mA h g^(-1) for KNaV_(10).Even after 60 discharge/charge cycles at 50 mA g^(-1),it displayed a capacity of 180 mA h g^(-1).The 1D tunnel in MgV_(10) facilitates the Li+ion transport and provides spatial Li storage sites,which promotes the electrochemical performance in LIBs.Moreover,the Mg^(2+)ions remained stable during battery cycling and promoted the 3D structure stability.This work demonstrates promising guidelines for the structural design of POVs based materials for Li storage.展开更多
CONSPECTUS:Electrochemical and photoelectrochemical conversion of renewable energy sources into useful chemicals and fuels is of paramount importance for future sustainable technologies.Renewable energy conversion req...CONSPECTUS:Electrochemical and photoelectrochemical conversion of renewable energy sources into useful chemicals and fuels is of paramount importance for future sustainable technologies.Renewable energy conversion requires catalysts for multielectron redox reactions such as water oxidation and reduction(toward water splitting systems).Developing efficient catalysts for multielectron redox reactions is a great challenge in current science and technology.Metal oxides have been extensively researched to be applied to a large variety of photonic and electronic devices due to the wide range of electronic properties of conducting,semiconducting,and insulating and diverse catalytic properties at their surface depending on the exposing facet,as well as physical and chemical robustness under ambient conditions.We aspire to the development of an easy technique available for large-scale production of metal oxide films based on simple casting and calcination to adopt a strategy for controlling the formation and growth of metal oxide films by ligands to metal centers in precursors.We have developed an easy preparation technique of mono-and multimetallic oxide films,termed the“mixed metal-imidazole casting(MiMIC)method”,by which metal oxide films are generated tightly on various electrode substrates by casting precursor solutions or suspensions containing component metal salts in a mixed solvent of methanol/imidazole derivative as a ligand,followed by calcination.The general versatility of the MiMIC method encourages us to hunt new metal oxide films as efficient catalysts for the multielectron redox reactions,because the rigid adherability of films formed on a current collector electrode is necessary for essential evaluation of the catalytic performance of the metal oxide films.In this Account,we expound synthesis and characterization of a variety of mono-and multimetallic oxide films using the MiMIC method and its application to electro-and photoelectrocatalysis for water splitting and oxygen reduction,which are important key reactions in future sustainable technology.The adherability of these films onto the electrode surface is prominent although their morphology,crystallinity,and nanostructures depend on the metal oxide materials,which is one of the important factors to induce high performance of the metal oxide films for electro-and photoelectrocatalysis.Imidazole derivatives were found to act as a source of nitrogen for the N-doping to a metal oxide lattice,and a structure-directing agent for the anisotropic crystallization,as well as a binder among constituting nanoparticles to lead to the rigid adherability of films on the substrate.These findings surely expand material development to a great extent,by not only changing the metal compositions but also being based on band engineering due to doping of representative elements and crystal facet control of metal oxide films.展开更多
基金financially supported by the Key Research and Development(R&D)Projects of Shanxi Province(202202040201005)the Graduate Innovation Project of Shanxi Province(No.2024SJ261)。
文摘Currently,simultaneous regulation of external morphology and internal electronic structure for Na_(3)V_(2)(PO_(4))_(3)(NVP)is rarely realized.Herein,complexes of β-cyclodextrin(βCD)and ethylenediaminetetraacetic acid ferric sodium salt(EDTAFeNa)are utilized for the one-step preparation of NVP with spherical morphology as well as Fe substitution.βCD is initially hydrolyzed into glucose,and then carbon microspheres with numerous pores are formed through continuous dehydration and carbonization.The intermediate hydroxymethylfurfural is rich in active functional groups,which are attractive for the V/P-contained raw materials.Accordingly,the nucleation sites for NVP are successfully limited in the spherical framework,possessing a superior surface area of 97.15 g m^(-2).Furthermore,the beneficial Fe in EDTAFeNa enters into the NVP bulk to construct a novel Fe-doped Na_(3)V_(1.95)Fe_(0.05)(PO_(4))_(3)(NVP/β-ISC)material.Fe-substitution induces significant optimizations of electronic structure for NVP,which has been verified by the newly generated abundant oxygen vacancies and extended V-O bond length.Moreover,a multielectron reaction is activated,resulting from the V^(4+)/V^(5+)redox couple.The charge compensation mechanism of NVP/β-ISC is also deeply investigated.Density functional theory(DFT)calculations theoretically elaborate the mechanism of Fe-doping.Consequently,NVP/β-ISC reveals superior sodium storage performance in both half and full cells and even at different extreme conditions(needling,soaking,bending,and freezing).
基金Project supported by the National Key Basic Research Special Foundation （NKBRSF） （Grant No TG1999075207） and the National Natural Science Foundation of China （Grant Nos 10104003, 90206003 and 60378012） and the China Postdoctoral Science Foundation （Grant No 2003034093）.
文摘The field-ionization Coulomb explosion model is extended to investigate the multielectron dissociative ionization process of N2 molecule irradiated by an intense femtosecond laser field with an arbitrary polarization. The ionization process of N2 molecule is found to be optimal at the critical internuclear distance Rc=7a.u., which is independent of the laser polarization state, the molecular explosion channel and the angle between the molecular axis and the direction of laser electric field. The kinetic energies of the ion fragments are identical in the cases of linear and circular polarizations at the same incident laser intensity. However, the probability of electron ionization is very sensitive to the above three parameters. At the critical distance Rc=7a.u. the angular dependence of the threshold intensity for the over-the-barrier ionization leads to the geometric alignment of molecules in the case of linear polarization. The threshold intensity in the case of circular polarization is apparently higher than that in the case of linear polarization, which can well explain the significant decrease of ionization in the case of circular polarization. The numerical calculations are compared with the experimental measurements.
基金supported by the Deutsche Forschungsgemeinschaft(DFG)through the SPP 2262 program MemrisTec(Memristive Devices Toward Smart Technical Systems).Project number 536022773(2DPOMristor).
文摘Gold and atomically precise polyoxometalates(POMs)are widely used materials with electron reservoir redox properties.The combination of optically excited gold nanoparticles,gold surface/tip electrodes,or molecular gold(I)complexes with{V_(6)^(V)}Lindqvist-,{MnMo_(6)^(VI)}Anderson-Evans-,and{PW_(12)^(VI)}Keggin-type POM structures leads to interfacial multielectron transformations with far-reaching implications for electronics,photonics,biomedical diagnostics,and catalysis.
基金supported the ACS Petroleum Research Fund(65171-DNI3)Rutgers,The State University of New Jersey.
文摘The introduction of redox-active ligands into transition metal complexes can lead to novel redox behavior due to the ability of these ligands to serve as electron reservoirs.This feature is especially attractive in earth-abundant transition metal systems that typically favor one-electron redox processes and radical reactivity,as opposed to the two-electron redox cycles common with the noble metals.The redox flexibility afforded by redox-active ligands can enable substrate activation and/or bond forming and breaking processes that would otherwise be inaccessible with traditional redox-innocent ligands.This review discusses key examples of stoichiometric substrate activation and organic transformations facilitated by redox-active ligand-promoted multielectron reactivity at earth-abundant metal complexes.We highlight the electrochemical properties of these systems in relation to their substrate reactivity,where,in many cases,the complexes exhibit sequential one-electron redox events.Only a few examples have achieved electrocatalytic reactivity based on two-electron redox features,which underscores the untapped potential for further development of redox-active ligand systems to expand the capabilities of earth-abundant metal complexes in electrocatalysis.
基金supported in part by the Grants-in-Aid for Scientific Research(Grant No.20H02663 to KT,and 21J11942 to TT)of the Japan Society for the Promotion for Science(JSPS)the JAEA Nuclear Energy S&T and the Human Resource Development Project through concentrating wisdom(Grant No.JPJA19P19209861)the International Research Frontiers Initiative(IRFI)of Institute of Innovative Research,Tokyo Institute of Technology.
文摘In most cases,the redox activity of a U^(Ⅵ)O_(2)^(2+) complex is regarded as metal-centered phenomena,because uranium has small energy gaps amongst the 5f/6d/7s subshells,thereby exhibiting a wide range of oxidation states,commonly from+Ⅲ to+Ⅵ or in some cases even+I or+Ⅱ.While a wide variety of redox-active ligands are known for use as transition metal complexes including multi-electron reduction that could facilitate inert bond or small molecule activation,only a few such examples are known for U^(Ⅵ)O_(2)^(2+).In this study,three U^(Ⅵ)O_(2)^(2+)complexes bearing α-diimine-,o-quinonediimine-and 2,6-diiminopyridine-based ligands were synthesized,which exhibited two redox couples in the range of−0.79 V to−2.02 V vs.Fc+/0 to give singly-and doubly-reduced complexes by stepwise reduction.Unique electronic transitions of U^(Ⅵ)O_(2)^(2+) complexes with a variety of low-lying excited states helped us to combine spectroelectrochemistry and time-dependent density functional theory(TD-DFT)calculations which complemented each other to assign the redox-active site in these U^(Ⅵ)O_(2)^(2+) complexes,i.e.,whether or not a ligand of interest becomes redox-active.During all the redox processes observed here,the ligands employed are found to be exclusively redox-active,i.e.,non-innocent,whereas the centered U^(Ⅵ)O_(2)^(2+) is just“spectating”and remains unchanged,i.e.,innocent.Whereas the double reduction of the U^(Ⅵ)O_(2)^(2+) complexes usually involves breaking of strong UuO bonds,in the present examples this is not required and therefore a basis for the synthesis of new types of uranium molecular catalysts and magnetic materials may be found.
基金supported by the Spanish MINECO(Projects PID2019-109735GB-I00Unidad de Excelencia María de Maeztu CEX2019-000919-M)+2 种基金the Generalitat Valenciana(AICO/2020/183 and AICO/2021/295)funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement no 748921-SIMOF.R.R.thanks the Generalitat Valenciana and CAPES/BRASIL for the doctoral(GRISOLIAP/2017/057)postdoctoral(88887.798611/2022-00)grants。
文摘Designing and implementing multielectron transfer and single-molecule magnet properties in spin crossover compounds constitute a promising way to obtain a new class of multiresponsive and multifunctional materials.This contribution uses N-phenyl-substituted pyridine-2,6-diimine(PDI)ligands to explore a novel family of spin-crossover cobalt(Ⅱ)complexes,with general formula[CoL_(2)](ClO_(4))_(2)·xH_(2)O[L=4-MePhPDI(1,x=1),4-MeOPhPDI(2,x=0),4-MeSPhPDI(3,x=0),4-Me_(2)NPhPDI(4,x=0.5),and 2,4-Me_(2)PhPDI(5,x=0)].These mononuclear six-coordinate octahedral cobalt(Ⅱ)bis(chelating)complexes incorporate tridentate PDI derivatives with various electron-donating substituents at para(X_(4)=Me,OMe,SMe,and Me_(2)N)or ortho and para positions(X_(2),X_(4)=Me)of terminal phenyl rings.Our investigations reveal that these complexes exhibit both thermally-induced low-spin(LS)/high-spin(HS)transition and field-induced slow magnetic relaxation in the LS(S=1/2)and HS(S=3/2)states.Moreover,they display a dual multiredox behaviour featuring one-electron oxidation of the paramagnetic Co^(Ⅱ)ion to the diamagnetic Co^(Ⅲ)ion and stepwise two-electron reduction of each PDI ligand to the corresponding imine-type PDI·−π-radical anion and diimine-type PDI^(2−)dianion,which positions them as candidates for prototypes of spin quantum transistors and capacitors,offering potential applications in quantum information processing.
基金partly supported by the National Natural Science Foundation of China(No.22301108)the Project Startup Foundation for Distinguished Scholars of Jiangsu University(Nos.4111310026 and 5501310014).
文摘Novel benzo-bridged hexaphyrin(2.1.2.1.2.1)and its copper complex were synthesized.Single-crystal structures showed typical figure-of-eight Huckel topologies.NMR,NICS,HOMA,ACID,and EDDB analysis supported their non-aromatic properties owning to the strong local aromatic benzo rings cutting the global aromatic ring of the benzo-bridged figure-of-eight hexaphyrin(2.1.2.1.2.1).The redox properties and degenerate HOMOs and LUMOs levels indicate multielectron donating and accepting abilities.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 92250306 and 12304302)the Natural Science Foundation of Jilin Province, China (Grant Nos. YDZJ202101ZYTS157 and YDZJ202201ZYTS314)the Scientific Research Foundation of Jilin Province Education Department, China (Grant No. JJKH20230283KJ)。
文摘Molecular high-order harmonic spectroscopy is a significant advancement in ultrafast science, enabling the measurement of multielectron dynamics with attosecond temporal resolution. The fine structures observed in the molecular harmonic spectrum provide crucial insights into the structural or multielectron dynamical effects induced by intense laser fields. In this study, we measure the high-order harmonic spectrum of aligned CO_(2) molecules contributed from short trajectories. Two distinct groups of minima are identified in the plateau region. Our findings indicate that the deeper-lying molecular orbitals and two-center interference play significant roles in molecular harmonic generation. The results pave the way for advancing the understanding of multielectron dynamics in polyatomic molecules under intense laser fields.
基金supported by the NSFC under Grant Nos.11374315 and 12074395the Invited Scientist Program of CNRS at Ecole Polytechnique,Palaiseau,France。
文摘The capacity to predict X-ray transition and K-edge energies in dense finite-temperatur plasmas with high precision is of primary importance for atomic physics of matter under extreme conditions.The dual characteristics of bound and continuum states in dense matter are modeled by a valence-band-like structure in a generalized ion-sphere approach with states that are either bound,free,or mixed.The self-consistent combination of this model with the Dirac wave equations of multielectron bound states allows one to fully respect the Pauli principle and to take into account the exact nonlocal exchange terms.The generalized method allows very high precision without implication of calibration shifts and scaling parameters and therefore has predictive power.This leads to new insights in the analysis of various data.The simple ionization model representing the K-edge is generalized to excitation–ionization phenomena resulting in an advanced interpretation of ionization depression data in near-solid-density plasmas.The model predicts scaling relations along the isoelectronic sequences and the existence of bound M-states that are in excellent agreement with experimental data,whereas other methods have failed.The application to unexplained data from compound materials also gives good agreement without the need to invoke any additional assumptions in the generalized model,whereas other methods have lacked consistency.
基金Supported by the National Natural Science Foundation of China under Grant Nos 10434100, 10574018 and 10574020.
文摘Cross sections of electron-loss in H（1s）＋ H（1s） collisions and total collisional destruction of H（2s） in H（1s） 4- H（2s） collisions are calculatted by four-body classical-trajectory Monte Caylo （CTMC） method and compared with previous theoretical and experimental data over the energy range of 4-100 keV. For the former a good agreement is obtained within different four-body CTMC calculations, and for the incident energy Ep 〉 10 keV, comparison with the experimental data shows a better agreement than the results calculated by the impact parameter approx- imation. For the latter, our theory predicts the correct experimental behaviour, and the discrepancies between our results and experimental ones are less than 30%. Based on the successive comparison with experiments, the cross sections for excitation to H（2p）, single- and double-ionization and H- formation in H（2s）＋H（2s） collisions are calculated in the energy range of 4-100 keV for the first time, and compared with those in H（1s）＋H（1s） and H（1s）＋U（2s） collisions.
基金supported by the National Natural Science Foundation of China(52072118,51772089)the Youth 1000 Talent Program of China+3 种基金the Research and Development Plan of Key Areas in Hunan Province(2019GK2235)the Key Research and Development Program of Ningxia(2020BDE03007)the China Postdoctoral Science Foundation(2019M653649)the Guangdong Basic and Applied Basic Research Fund(2019A1515110518,2019A1515111188,2020B0909030004)。
文摘Developing suitable anode materials for potassium-ion batteries(PIBs)remains a great challenge owing to the limited theoretical capacity of active materials and large radius of K+ion(1.38?).To solve these obstacles,by integrating the principles of multielectron transfer and rational porous crystal framework,we creatively propose the monoclinic Cu_(3)(OH)_(2)V_(2)O_(7)·2H_(2)O(CVO)as a novel anode for PIBs.Furthermore,inspired by the metastable nature of CVO under high temperature/pressure,we skillfully design a facile hydrothermal recrystallization strategy without the phase change and surfactants addition.Thus,for the first time,the porous composite of Cu_(3)(OH)_(2)V_(2)O_(7)·2H_(2)O nanobelts covered in situ by reduced graphene oxide(CVO NBs/r GO)was assembled,greatly improving the deficiencies of CVO.When used as a novel anode for PIBs,CVO NBs/r GO delivers large specific capacity(up to 551.4 m Ah g^(-1)at 50 m A g^(-1)),high-rate capability(215.3 m Ah g^(-1)at 2.5 A g^(-1))and super durability(203.6 m Ah g^(-1)at 500 m A g^(-1)even after 1000 cycles).The outstanding performance can be ascribed to the synergistic merits of desirable structural features of monoclinic CVO nanobelts and the highly conductive graphene 3D network,thus promoting the composite material stability and electrical/ionic conductivity.This work reveals a novel metal vanadate-based anode material for PIBs,would further motivate the subsequent batteries research on M_(3)(OH)_(2)V_(2)O_(7)-n H_(2)O(M;Co,Ni,Cu,Zn),and ultimately expands valuable fundamental understanding on designing other high-performance electrode materials,including the combined strategies of multielectron transfer with rational porous crystal framework,and the composite fabrication of 1D electrode nanostructure with conductive carbon matrix.
基金supported by the National Natural Science Foundation of China(21601058 and 21771112)111 project(B12015)the Hunan Provincial Natural Science Foundation of China(2018JJ3146).
文摘Polyoxometalate-based metal–organic frameworks(POM-based MOFs)are extended structures that simultaneously possess the virtues of POMs and MOFs.They have been attracting immense attention because of their diverse architectures and charming topologies,and also due to their probable application prospects in the areas of catalysis,sorption and separation,magnetism,proton conduction,lithium-ion batteries,supercapacitors,electrochemistry,medicine,and so on.In particular,the strong acidity,multielectron redox and photoactivity of POMs combined with the high surface area and adjustable pore size of MOFs make them excellent heterogeneous catalysts in various kinds of organic reactions.This short review firstly presents a concise introduction related to POMs,MOFs and POM-based MOFs,followed by the synthetic strategies of POM-based MOFs.The structural features and catalysis properties of representative POM-based MOFs have been classified and summarized according to different catalytic reactions,including acidity,oxidation,photocatalysis,electrocatalysis and other types of catalysis.The challenges present research situations,and prospects for the preparation and catalytic properties of POM-based MOFs are discussed.
基金support from the Swiss National Science Foundation grant number 178793the Ecole Polytechnique Fédérale de Lausanne(EPFL).
文摘Here we have explored the ability of Schiff bases to act as electron reservoirs and to enable the multielectron reduction of small molecules by lanthanide complexes.We report the reductive chemistry of the Ln_((III))complexes of the tripodal heptadentate Schiff base H_(3)trensal(2,2’,2’’-tris(salicylideneimino)triethylamine),[Ln_(III)(trensal)],1-Ln(Ln=Sm,Nd,Eu).We show that the reduction of the[Eu^(III)(trensal)]complex leads to the first example of a Eu^((II))Schiff base complex[{K(μ-THF)(THF)_(2)}_(2){EuII(trensal)}_(2)],3-Eu.In contrast the one-and two-electron reduction of the[NdIII(trensal)]and[SmIII(trensal)]leads to the intermolecular reductive coupling of the imino groups of the trensal ligand and to the formation of one and two C-C bonds leaving the metal center in the+3 oxidation state.The resulting one-and two electron reduced complexes[{K(THF)_(3)}_(2)Ln_(2)(bis-trensal)],2-Ln,and[{K(THF)_(3)}_(2){K(THF)}_(2)Ln_(2)(cyclo-trensal)],4-Ln(Ln=Sm,Nd)are able to effect the reductive disproportionation of carbon dioxide by transferring the electrons stored in the C-C bonds to CO_(2)to selectively afford carbonate and CO.The selectivity of the reaction contrasts with the formation of multiple CO_(2)reduction products previously reported for a U_((IV))-trensal system.
基金financially supported by the National Natural Science Foundation of China(No.21603162 and 51671145)Tianjin Sci.&Tech.Program(17JCYBJC21500)+1 种基金major projects of new materials of Tianjin city(16ZXCLGX00120)the Fundamental Research Funds of Tianjin University of Technology.
文摘Polyoxometalates act as an electron sponge,processing multielectron redox reactions and acting as a fast ionic conductor.They show great potential as promising electrode materials for next-generation lithium ion batteries(LIBs).However,there are still some fundamental issues which should be solved before their application can be realized,such as determining the stable structural feature with reversible Li+ion insertion/desertion.In this work,polyoxovanadates(POVs)based materials of K_(4)Na_(2)V_(10)O_(28)·nH_(2)O(KNaV_(10))and Mg_(2)(NH_(4))2V_(10)O_(28)·nH_(2)O(MgV_(10))have been prepared and used as the electrode material for a Li+ion reservoir.The 10-core polyoxovanadate is demonstrated as a anionic building block and the 3D extended structure has been smartly tuned by counter cations.For MgV_(10),a 1D tunnel with an approximate size of 3Å×10Å was formed along the a axis by Mg^(2+)ions and[V_(10)O_(28)]^(6-)polyanions.The MgV_(10) shows a higher capacity,cycling stability,and rate performance than that of KNaV_(10) without tunnels.The capacity of MgV_(10) is about 160 mA h g^(-1) at a high discharge rate of 250 mA g^(-1),while it is only 118 mA h g^(-1) for KNaV_(10).Even after 60 discharge/charge cycles at 50 mA g^(-1),it displayed a capacity of 180 mA h g^(-1).The 1D tunnel in MgV_(10) facilitates the Li+ion transport and provides spatial Li storage sites,which promotes the electrochemical performance in LIBs.Moreover,the Mg^(2+)ions remained stable during battery cycling and promoted the 3D structure stability.This work demonstrates promising guidelines for the structural design of POVs based materials for Li storage.
基金supported by JSPS KAKENHI Grant Numbers JP21H02042,JP22K18309,and JP22K14762.
文摘CONSPECTUS:Electrochemical and photoelectrochemical conversion of renewable energy sources into useful chemicals and fuels is of paramount importance for future sustainable technologies.Renewable energy conversion requires catalysts for multielectron redox reactions such as water oxidation and reduction(toward water splitting systems).Developing efficient catalysts for multielectron redox reactions is a great challenge in current science and technology.Metal oxides have been extensively researched to be applied to a large variety of photonic and electronic devices due to the wide range of electronic properties of conducting,semiconducting,and insulating and diverse catalytic properties at their surface depending on the exposing facet,as well as physical and chemical robustness under ambient conditions.We aspire to the development of an easy technique available for large-scale production of metal oxide films based on simple casting and calcination to adopt a strategy for controlling the formation and growth of metal oxide films by ligands to metal centers in precursors.We have developed an easy preparation technique of mono-and multimetallic oxide films,termed the“mixed metal-imidazole casting(MiMIC)method”,by which metal oxide films are generated tightly on various electrode substrates by casting precursor solutions or suspensions containing component metal salts in a mixed solvent of methanol/imidazole derivative as a ligand,followed by calcination.The general versatility of the MiMIC method encourages us to hunt new metal oxide films as efficient catalysts for the multielectron redox reactions,because the rigid adherability of films formed on a current collector electrode is necessary for essential evaluation of the catalytic performance of the metal oxide films.In this Account,we expound synthesis and characterization of a variety of mono-and multimetallic oxide films using the MiMIC method and its application to electro-and photoelectrocatalysis for water splitting and oxygen reduction,which are important key reactions in future sustainable technology.The adherability of these films onto the electrode surface is prominent although their morphology,crystallinity,and nanostructures depend on the metal oxide materials,which is one of the important factors to induce high performance of the metal oxide films for electro-and photoelectrocatalysis.Imidazole derivatives were found to act as a source of nitrogen for the N-doping to a metal oxide lattice,and a structure-directing agent for the anisotropic crystallization,as well as a binder among constituting nanoparticles to lead to the rigid adherability of films on the substrate.These findings surely expand material development to a great extent,by not only changing the metal compositions but also being based on band engineering due to doping of representative elements and crystal facet control of metal oxide films.
