The structure and binding energy of copper clusters of the size range 70 to 150 were studied by using the embeddedatom method. The stability of the structure of the clusters was studied by calculating the average bind...The structure and binding energy of copper clusters of the size range 70 to 150 were studied by using the embeddedatom method. The stability of the structure of the clusters was studied by calculating the average binding energy per atom, first difference energy and second difference energy of copper cluster. Most of the copper clusters of the size n=70-150 adopt an icosahedral structure. The results show that the trends are in agreement with theoretic prediction for copper clusters. The most stable structures for copper clusters are found at n=77, 90, 95, 131, 139.展开更多
The soft deposition of Cu clusters on a Si （001） surface was studied by molecular dynamics simulations. The embedded atom method, the Stillinger-Weber and the Lennar-Jones potentials were used to describe the intera...The soft deposition of Cu clusters on a Si （001） surface was studied by molecular dynamics simulations. The embedded atom method, the Stillinger-Weber and the Lennar-Jones potentials were used to describe the interactions between the cluster atoms, between the substrate atoms, and between the cluster and the substrate atoms, respectively. The Cu13, Cu55, and Cu147 clusters were investigated at different substrate temperatures. We found that the substrate temperature had a significant effect on the Cn147 cluster. For smaller Cu13 and Cu55 clusters, the substrate temperature in the range of study appeared to have little effect on the mean center-of-mass height. The clusters showed better degrees of epitaxy at 800 K. With the same substrate temperature, the Cu55 cluster demonstrated the highest degree of epitaxy, followed by Cu147 and then Cu13 clusters. In addition, the Cu55 cluster showed the lowest mean center-of-mass height. These results suggested that the Cu55 cluster is a better choice for the thin-film formation among the clusters considered. Our studies may provide insight into the formation of desired Cu thin films on a Si substrate.展开更多
The melting and freezing processes of CUN （N =180, 256, 360, 408, 500, 628 and 736） nanoclnsters are simulated by using micro-canonical molecular dynamics simulation technique, The potential energies and the heat ca...The melting and freezing processes of CUN （N =180, 256, 360, 408, 500, 628 and 736） nanoclnsters are simulated by using micro-canonical molecular dynamics simulation technique, The potential energies and the heat capacities as a function of temperature are obtained. The results reveal that the melting and freezing points increase almost linearly with the atom number in the cluster increasing. All copper nanoclusters have negative heat capacity around the melting and freezing points, and hysteresis effect in the melting/freezing transition is derived in CUN nanoclusters for the first time.展开更多
We have studied the reaction mechanism of CO oxidation on the Cu13 cluster via density functional theory. There are two main reaction pathways to be considered： Eley-Rideal（ER） and Langmuir-Hinshelwood（LH） mechan...We have studied the reaction mechanism of CO oxidation on the Cu13 cluster via density functional theory. There are two main reaction pathways to be considered： Eley-Rideal（ER） and Langmuir-Hinshelwood（LH） mechanisms, respectively. According to these two main reaction mechanisms, we have obtained five reaction pathways for the first CO oxidation（denoted as RER1,RER2, RLH1, RLH2 and RLH3, respectively）： RER1 is COgas ＋ O2（ads） → O（ads） ＋ CO2（gas）; RER2 is COgas ＋ O2（ads） → CO3（ads） → O（ads） ＋ CO2（gas）; RLH1 refers to CO（ads） ＋ O2（ads） → O（ads） ＋ CO2（gas）; RLH2 refers to CO（ads） ＋ O2（ads） → OOCO（ads） → O（ads） ＋ CO2（gas） and RLH3 refers to O2（ads） ＋ CO（ads）→ O（ads） ＋ O（ads） ＋ CO（ads） → O（ads） ＋ CO2（gas）. These pathways have low energy barriers and are strongly exothermic, suggesting the Cu13 cluster is very favorable catalyst for the first CO oxidation. However, there are higher energy barriers of 99. 8 and 45.4 kJ/mol in the process of producing and decomposing intermediates along the RLH2 and RER2, indicating that RER1, RLH1 and RLH3 are superior pathways with lower energy barriers, especially the RER1 channel. Thereafter, the second CO is more prone to react with the remaining oxygen atom on Cu13 along the ER channel in comparison with the LH pathway, in which the moderate barrier is 70.0 kJ/mol and it is exothermic by 59.6 kJ/mol. Furthermore, the interaction between the absorbate and cluster is analyzed by electronic analysis to gain insights into high activity of the copper cluster.展开更多
The major impediment to the additional industrialization of water splitting is the high cost of the co-catalyst made of noble metals and the sacrificial reagent. A binary photocatalytic system, consisting of B-doped g...The major impediment to the additional industrialization of water splitting is the high cost of the co-catalyst made of noble metals and the sacrificial reagent. A binary photocatalytic system, consisting of B-doped g-C_(3)N_(4) nanosheets(Cu_(20)@BCN-X) and atomically accurate copper clusters, is designed in this study. The copper clusters serve as co-catalysts for H_(2) evolution and exhibit Pt-like activity, whereas the nanosheets serve as carriers and semiconductor components for O_(2) evolution. Such binary system, created using simple techniques, demonstrates hydrogen bonding interactions that promote synergistic effects and efficient binding and charge transfer across the interface between the two components. Band position manipulation of carbon nitride nanosheets demonstrates a Z-scheme charge transfer mechanism between the nanosheets and copper clusters. This photocatalytic system can accomplish the photocatalytic overall water splitting process(259.9 μmol g^(-1)h^(-1)of H_(2) and 129.4 μmol g^(-1)h^(-1)of O_(2)) without using sacrificial agents or noble metal co-catalysts. This work lays the foundation for the design of overall water splitting catalysts by precisely manipulating the energy levels, and it also paves the way for commercialized photocatalytic catalysts that do not require noble metals or sacrificial chemicals.展开更多
The catalytic epoxidation of olefin was investigated on two copper complex-modified molybdenum oxides with a 3D supramolecular structure, [Cu（bipy）]4[Mo15O47].2H2O （1） and [Cu1（bix）][（Cu1bix） （δ-MoVl8O26）0....The catalytic epoxidation of olefin was investigated on two copper complex-modified molybdenum oxides with a 3D supramolecular structure, [Cu（bipy）]4[Mo15O47].2H2O （1） and [Cu1（bix）][（Cu1bix） （δ-MoVl8O26）0.5] （2） （bipy = 4,4＇-bipyridine, bix = 1,4-bis（imidazole-1-ylmethyl）benzene）. Both compounds were catalytically active and stable for the epoxidation of cyclooctene, 1-octene, and styrene with tert-butyl hydroperoxide （t-BuOOH） as oxidant. The excellent catalytic performance was attributed to the presence of stable coordination bonds between the molybdenum oxide and copper complex, which resulted in the formation of easily accessible Mo species with high electropositivity. In addition, the copper complex also acted as an active site for the activation of t-BuOOH, thus im- proving these copper complex-modified polyoxometalates.展开更多
The activation of molecular oxygen is an important step in metal-catalyzed oxidation reactions and a hot subject for the research of gas-phase metal clusters.It is known that the Ag and Au clusters readily re-act with...The activation of molecular oxygen is an important step in metal-catalyzed oxidation reactions and a hot subject for the research of gas-phase metal clusters.It is known that the Ag and Au clusters readily re-act with O_(2)when they have open shell electronic structures.Distinct from this,here we observed Cu_(n)^(-)(n=7−20)clusters of both open and closed shells possess high reactivity with O_(2)with few exceptions.In a combination with ab initio calculations,we demonstrate that the activation of O_(2)on the even-and odd-sized Cu_(n)^(-)clusters follows the single and double electron transfer models,respectively.Such phe-nomenon of metal clusters with different basicity to activate oxygen is enabled by the leveling effect of spin accommodation.The activity of Cu_(n)^(-)clusters is correlated to the HOMO level,and for the close-shell clusters is also governed by the vertical spin excitation energy(VSE).In encountering the attack of dioxygen,the activity of the copper cluster anions not only depends on their basicity to donate electrons,but also closely associated with the cluster sizes.Small copper clusters Cu_(n)^(-)(n=7−13)can dissociate O_(2)spontaneously,while large clusters require extra energies and display close relationship between the reaction rates and electronic vertical detachment energies(VDE).Our work illuminates a novel reaction mechanism between Cu_(n)^(-)clusters and O_(2),which sheds light in manipulating the activity and stability of coinage clusters by controlling the spin and charge states.展开更多
The title compound [Cu(dtp) PPh3]2 (dtp=S2,P(OEt)2) was prepared by heating the mononuclear compound Cu(dtp)(PPh3)2 in CH3CN solution.It crystallizes in the triclinic space group P1 with parameters a=9.71 6(5),b=11.02...The title compound [Cu(dtp) PPh3]2 (dtp=S2,P(OEt)2) was prepared by heating the mononuclear compound Cu(dtp)(PPh3)2 in CH3CN solution.It crystallizes in the triclinic space group P1 with parameters a=9.71 6(5),b=11.026(5),c=12.475(4) A.α=78.16(3)°,β=102. 64(4), γ=114.34(4)°,V=1178(1)A 3,Z=1,Dc=1.44 g/cm3,MoKα(λ=0.71069 A) μ=12. 48cm-1,F(000)=528.Final R=0.041.Rω= 0. 052 for 3653 unique intensity data(I≥3σ(I)).The molecule of the title compound can be viewed as a centrosymmetric dimer with two[Cu(dtp)(PPh3)] units,which are bridged by two S atoms belonging to the dtp ligands.The exact planar[Cu2S2] core and two[CuS2P] four-membered rings form a chair conformation.The Cu…Cu distance is 2.991(5) A.展开更多
In this paper, single crystal EPR study of a new binuclear copper (Ⅱ) cluster compound-[Cu2(α-C(10) H7CH2CO2)4 (DMF)2]·[DMF]2·H2O](DMF= (CH3)2NCOH) at room temperature is reported. The lines of △Ms=±...In this paper, single crystal EPR study of a new binuclear copper (Ⅱ) cluster compound-[Cu2(α-C(10) H7CH2CO2)4 (DMF)2]·[DMF]2·H2O](DMF= (CH3)2NCOH) at room temperature is reported. The lines of △Ms=±1 allowing transition and △M=2 forbiding transition are shown in EPR spectra. The experimental data are consistent with the calculated results by the leastsquares fitting prograrn in three principal planes of g and D tensors. The spin Hamiltonian parameters are as follows: gx=2. 1482, gy=2. 0529 ,gz=2. 3905, D= 0. 348 cm￣(-1) and E =0. 01 cm-1. The diagrams of the energy levels have been obtained when the magnetic field is oriented to three principal axes. The polycrystal EPR spectra have been measured at room temperature and 77K, respectively.and the parameters of these spectra are given (g∥= 2. 094, g⊥= 2. 425, D= 0. 37 cm-1,E=0). The parameter of the isotropic magnetic exchange interaction J=-254cm-1 is determined, and that of the anisotropic magnetic exchange J1=-153 cm-1 is calculated. The average magnetic susceptibility of the polycrystal sample χ= 1. 39 ×10-6 (c. g. s) has been measured by Faraday powder method. Thus the average magnetic mornent μ=1. 43 B. M. can be calculated. It is shown that the exchange interactions between the metal ions of the binuclear copper(Ⅱ) cluster compound are confirmed antiferromagnetic In nature.展开更多
A novel tetranuclear copper cluster[Cu4(μ-L)6Cl2]was constructed by 2-(1H-pyrazol-3-yl)pyridine(HL)under hydrothermal conditions,and structurally concluded by single-crystal X-ray diffractions,elemental analyses and ...A novel tetranuclear copper cluster[Cu4(μ-L)6Cl2]was constructed by 2-(1H-pyrazol-3-yl)pyridine(HL)under hydrothermal conditions,and structurally concluded by single-crystal X-ray diffractions,elemental analyses and IR spectra.The title complex 1 was of triclinic system,space group■,C24H18ClCu2 N9,Mr=595.01,a=9.6497(13),b=11.4133(7),c=13.0919(15)?,α=99.166(7),β=108.707(11),γ=111.974(9)°,V=1200.7(2)?3,Z=2,Dc=1.997 g/cm^3,F(000)=706,μ(MoKα)=3.203 nm-1,Rint=0.0404,R=0.0536 and wR=0.1490 for4890 observed reflections with I>2σ(I).In this structure,complex 1 was the unimolecule with unprecedented tetranuclear cluster,which was expanded into a 2D network by wide-ranging C-H…Cl intermolecular hydrogen bonds and further exhibited a 3D supramolecular architecture based onπ-πstacking interactions.In addition,the complex was thermally stable up to 300℃and the solid state fluorescent property of 1 was examined and compared with the ligand.展开更多
In this paper, single crystal EPR study of a new binuclear copper (Ⅱ) cluster compound-[Cu2(α-C(10) H7CH2CO2)4 (DMF)2]·[DMF]2·H2O](DMF= (CH3)2NCOH) at room temperature is reported. The lines of △Ms=±...In this paper, single crystal EPR study of a new binuclear copper (Ⅱ) cluster compound-[Cu2(α-C(10) H7CH2CO2)4 (DMF)2]·[DMF]2·H2O](DMF= (CH3)2NCOH) at room temperature is reported. The lines of △Ms=±1 allowing transition and △M=2 forbiding transition are shown in EPR spectra. The experimental data are consistent with the calculated results by the leastsquares fitting prograrn in three principal planes of g and D tensors. The spin Hamiltonian parameters are as follows: gx=2. 1482, gy=2. 0529 ,gz=2. 3905, D= 0. 348 cm￣(-1) and E =0. 01 cm-1. The diagrams of the energy levels have been obtained when the magnetic field is oriented to three principal axes. The polycrystal EPR spectra have been measured at room temperature and 77K, respectively.and the parameters of these spectra are given (g∥= 2. 094, g⊥= 2. 425, D= 0. 37 cm-1,E=0). The parameter of the isotropic magnetic exchange interaction J=-254cm-1 is determined, and that of the anisotropic magnetic exchange J1=-153 cm-1 is calculated. The average magnetic susceptibility of the polycrystal sample χ= 1. 39 ×10-6 (c. g. s) has been measured by Faraday powder method. Thus the average magnetic mornent μ=1. 43 B. M. can be calculated. It is shown that the exchange interactions between the metal ions of the binuclear copper(Ⅱ) cluster compound are confirmed antiferromagnetic In nature.展开更多
This paper obtains the lowest-energy geometric structures and the electronic and magnetic properties of small CuNiN clusters by using all-electron density functional theory. The calculated results reveal that the Cu a...This paper obtains the lowest-energy geometric structures and the electronic and magnetic properties of small CuNiN clusters by using all-electron density functional theory. The calculated results reveal that the Cu atom prefers to occupy the apical site when N ≤ 9 and for the clusters with N = 10, the Cu atom starts to encapsulate in the cage. The CuNi7 and CuNi9 are magic clusters. The magnetism correlates closely with the symmetry of the clusters. For these clusters, the charge tends to transfer from the nickel atoms to the copper atoms. It finds that the doping of Cu atom decreases the stability of pure NiN clusters.展开更多
The process of graphene cleaning of a copper film by bombarding it with Ar_（13） clusters is investigated by the molecular dynamics method.The kinetic energies of the clusters are 5,10,20,and 30 eV and the incident a...The process of graphene cleaning of a copper film by bombarding it with Ar_（13） clusters is investigated by the molecular dynamics method.The kinetic energies of the clusters are 5,10,20,and 30 eV and the incident angles are θ= 90°,75°,60°,45°,and 0°.It is obtained that the cluster energy should be in the interval 20 eV-30 eV for effective graphene cleaning.There is no cleaning effect at vertical incidence（θ =0°） of Ar_（13） clusters.The bombardments at 45° and 90° incident angles are the most effective on a moderate and large amount of deposited copper,respectively.展开更多
A new hetero-six-nuclear cluster was synthesized and determined by X-ray diffraction technique. The four-carboxylate groups are bound to the Cu(II) atoms to form Cu(OR)4Cu paddle-wheel-type cage between two DMF as the...A new hetero-six-nuclear cluster was synthesized and determined by X-ray diffraction technique. The four-carboxylate groups are bound to the Cu(II) atoms to form Cu(OR)4Cu paddle-wheel-type cage between two DMF as the basis for the cluster. The distance of two copper(II) atoms is 2.642 ?, and they are bridged by the carboxylate groups. A huge system plane was auto-assembled by four host molecules and two Cu (II) ions, which was observed in the crystal structure.展开更多
A systematic study on the structures and electronic properties of copper clusters has been performed using the density functional theory. In the calculation, there are many isomers near the ground state for small copp...A systematic study on the structures and electronic properties of copper clusters has been performed using the density functional theory. In the calculation, there are many isomers near the ground state for small copper clusters. Our results show that the three-dimensional isomers of copper clusters start from Cu7 cluster and then show a tendency to form more compact structures. The results of the formation energy and the second derivative of binding energy with duster size show that besides N = 8, N =11 is also a magic number. Furthermore, it is the first time to find that the ground state of 11-atom clusters is a biplanar structure as same as the 13-atom cluster. The clear odd-even alternation as cluster size for the formation energy indicates the stability of electronic close shell existed in the range studied.展开更多
The weakness of visible and near-infrared light penetration depth limits the application of photodynamic therapy(PDT)in deep-seated tumors.Based on the high penetrability of X-rays,X-ray-induced PDT(X-PDT)is a promisi...The weakness of visible and near-infrared light penetration depth limits the application of photodynamic therapy(PDT)in deep-seated tumors.Based on the high penetrability of X-rays,X-ray-induced PDT(X-PDT)is a promising new method for treating deep-seated tumors.However,it requires the development of suitable X-ray-induced sensitizers that could employ X-ray energy to produce reactive oxygen species(ROS)efficiently.In this study,a novel X-rayinduced sensitizer(NanoSRF)was developed through a microemulsion method,in which copper iodine cluster compound Cu_(2)I_(2)(tpp)2(2,5-dm-pz)(CIP)and rose bengal(RB)worked as scintillator and photosensitizer,respectively.CIP was synthesized by a simple mechanical grinding method,and subsequently folic acid(FA)-modified albumin was introduced to enable its alliance with RB.NanoSRF exhibited excellent dispersion stability and generated a large amount of ROS under X-ray irradiation.The results of in vitro studies demonstrated its high selectivity for FA receptor-positive cancer cells.Following systemic administration,NanoSRF accumulated in H22 tumors of xenograft-bearing mice,and Xray irradiation(5.46 Gy)induced a significant inhibition rate of 96.7%in tumor growth.This study pioneers the use of copper iodide cluster as a scintillator in X-PDT,presenting new possibilities for designing scintillators with exceptional X-ray absorption and efficient X-PDT capabilities.展开更多
Stimuli-responsive luminescent materials have attracted significant attention in the development of smart photoactive materials for both fundamental research and technological applications.In this work,a new copper io...Stimuli-responsive luminescent materials have attracted significant attention in the development of smart photoactive materials for both fundamental research and technological applications.In this work,a new copper iodide cluster(1)with aggregationinduced emission(AIE)characteristic,was obtained combining Cu_(4)I_(4) core with rhodamine B derivative ligand.1 has reversible and distinct multi-stimuli-responsive luminescence for external temperature,volatile organic compound,and mechanical force.Significantly,1 exhibited unusual large blue shift(84 nm)after being ground,which originated from the change of intermolecular interactions.Moreover,1 exhibits high oxygen quenching efficiency for 82.2% at 1 bar.Mechanistic studies showed that the multi-stimuli-responsive luminescence properties of 1 can be attributed to the regulation of cluster-centered luminescence process,metal-to-ligand charge transfer process,halide-to-metal charge transfer luminescence process and aggregationinduced barrier to oxygen process.This work not only reports an AIE copper iodide cluster,but also provides a new strategy to develop multi-stimuli-responsive luminescence materials.展开更多
Three crystal architectures, including one organic compound of benzoyl peroxide（Ⅰ） and two clusters of tri-iron（Ⅲ） and bi-cupper（Ⅱ） with benzoic ligands（2 and 3）, were self-assembled by an in situ redox way...Three crystal architectures, including one organic compound of benzoyl peroxide（Ⅰ） and two clusters of tri-iron（Ⅲ） and bi-cupper（Ⅱ） with benzoic ligands（2 and 3）, were self-assembled by an in situ redox way of benzoyl peroxide oxidants reacting with Mo, Fe and Cu powders, respectively. X-ray crystallographic results show that both the asymmetry tri-iron（Ⅲ） cluster and the benzoylperoxide crystal architecture（2 and 1） with complicated 3D networks were constructed by intermolecular hydrogen-bonding interactions. Contrarily, the symmetrical bi-copper（Ⅱ） cluster crystal architecture（3）, only with π-π stacking between paralleled phenyl groups and without any intermolecular hydrogen-bonding interactions, only presented an 1D zigzag chain along the a-axis.展开更多
基金supported by the National Natural Science Foundation of China (Grant No 10375028)
文摘The structure and binding energy of copper clusters of the size range 70 to 150 were studied by using the embeddedatom method. The stability of the structure of the clusters was studied by calculating the average binding energy per atom, first difference energy and second difference energy of copper cluster. Most of the copper clusters of the size n=70-150 adopt an icosahedral structure. The results show that the trends are in agreement with theoretic prediction for copper clusters. The most stable structures for copper clusters are found at n=77, 90, 95, 131, 139.
基金Project supported by the National Natural Science Foundation of China (Grant No. 10375028)the US National Science Foundation Award (Grant No. CMMI-0700048)
文摘The soft deposition of Cu clusters on a Si （001） surface was studied by molecular dynamics simulations. The embedded atom method, the Stillinger-Weber and the Lennar-Jones potentials were used to describe the interactions between the cluster atoms, between the substrate atoms, and between the cluster and the substrate atoms, respectively. The Cu13, Cu55, and Cu147 clusters were investigated at different substrate temperatures. We found that the substrate temperature had a significant effect on the Cn147 cluster. For smaller Cu13 and Cu55 clusters, the substrate temperature in the range of study appeared to have little effect on the mean center-of-mass height. The clusters showed better degrees of epitaxy at 800 K. With the same substrate temperature, the Cu55 cluster demonstrated the highest degree of epitaxy, followed by Cu147 and then Cu13 clusters. In addition, the Cu55 cluster showed the lowest mean center-of-mass height. These results suggested that the Cu55 cluster is a better choice for the thin-film formation among the clusters considered. Our studies may provide insight into the formation of desired Cu thin films on a Si substrate.
文摘The melting and freezing processes of CUN （N =180, 256, 360, 408, 500, 628 and 736） nanoclnsters are simulated by using micro-canonical molecular dynamics simulation technique, The potential energies and the heat capacities as a function of temperature are obtained. The results reveal that the melting and freezing points increase almost linearly with the atom number in the cluster increasing. All copper nanoclusters have negative heat capacity around the melting and freezing points, and hysteresis effect in the melting/freezing transition is derived in CUN nanoclusters for the first time.
基金supported by the National Natural Science Foundation of China(Nos.51574090 and 21773030)Natural Science Foundation of Fujian Province(2017J01409)
文摘We have studied the reaction mechanism of CO oxidation on the Cu13 cluster via density functional theory. There are two main reaction pathways to be considered： Eley-Rideal（ER） and Langmuir-Hinshelwood（LH） mechanisms, respectively. According to these two main reaction mechanisms, we have obtained five reaction pathways for the first CO oxidation（denoted as RER1,RER2, RLH1, RLH2 and RLH3, respectively）： RER1 is COgas ＋ O2（ads） → O（ads） ＋ CO2（gas）; RER2 is COgas ＋ O2（ads） → CO3（ads） → O（ads） ＋ CO2（gas）; RLH1 refers to CO（ads） ＋ O2（ads） → O（ads） ＋ CO2（gas）; RLH2 refers to CO（ads） ＋ O2（ads） → OOCO（ads） → O（ads） ＋ CO2（gas） and RLH3 refers to O2（ads） ＋ CO（ads）→ O（ads） ＋ O（ads） ＋ CO（ads） → O（ads） ＋ CO2（gas）. These pathways have low energy barriers and are strongly exothermic, suggesting the Cu13 cluster is very favorable catalyst for the first CO oxidation. However, there are higher energy barriers of 99. 8 and 45.4 kJ/mol in the process of producing and decomposing intermediates along the RLH2 and RER2, indicating that RER1, RLH1 and RLH3 are superior pathways with lower energy barriers, especially the RER1 channel. Thereafter, the second CO is more prone to react with the remaining oxygen atom on Cu13 along the ER channel in comparison with the LH pathway, in which the moderate barrier is 70.0 kJ/mol and it is exothermic by 59.6 kJ/mol. Furthermore, the interaction between the absorbate and cluster is analyzed by electronic analysis to gain insights into high activity of the copper cluster.
基金supported by the National Natural Science Foundation of China (21971085)the Natural Science Foundation of Shandong Province (ZR2021MB008)the Jinan City “New University 20” Project (202228113)。
文摘The major impediment to the additional industrialization of water splitting is the high cost of the co-catalyst made of noble metals and the sacrificial reagent. A binary photocatalytic system, consisting of B-doped g-C_(3)N_(4) nanosheets(Cu_(20)@BCN-X) and atomically accurate copper clusters, is designed in this study. The copper clusters serve as co-catalysts for H_(2) evolution and exhibit Pt-like activity, whereas the nanosheets serve as carriers and semiconductor components for O_(2) evolution. Such binary system, created using simple techniques, demonstrates hydrogen bonding interactions that promote synergistic effects and efficient binding and charge transfer across the interface between the two components. Band position manipulation of carbon nitride nanosheets demonstrates a Z-scheme charge transfer mechanism between the nanosheets and copper clusters. This photocatalytic system can accomplish the photocatalytic overall water splitting process(259.9 μmol g^(-1)h^(-1)of H_(2) and 129.4 μmol g^(-1)h^(-1)of O_(2)) without using sacrificial agents or noble metal co-catalysts. This work lays the foundation for the design of overall water splitting catalysts by precisely manipulating the energy levels, and it also paves the way for commercialized photocatalytic catalysts that do not require noble metals or sacrificial chemicals.
基金supported by the National Natural Science Foundation of China(21173100 and 21320102001)~~
文摘The catalytic epoxidation of olefin was investigated on two copper complex-modified molybdenum oxides with a 3D supramolecular structure, [Cu（bipy）]4[Mo15O47].2H2O （1） and [Cu1（bix）][（Cu1bix） （δ-MoVl8O26）0.5] （2） （bipy = 4,4＇-bipyridine, bix = 1,4-bis（imidazole-1-ylmethyl）benzene）. Both compounds were catalytically active and stable for the epoxidation of cyclooctene, 1-octene, and styrene with tert-butyl hydroperoxide （t-BuOOH） as oxidant. The excellent catalytic performance was attributed to the presence of stable coordination bonds between the molybdenum oxide and copper complex, which resulted in the formation of easily accessible Mo species with high electropositivity. In addition, the copper complex also acted as an active site for the activation of t-BuOOH, thus im- proving these copper complex-modified polyoxometalates.
基金supported by the National Natural Science Foundation of China (Nos.91961204,11974068,21802146,21722308)the Fundamental Research Funds for the Central Universities of China (No.DUT20LAB110)。
文摘The activation of molecular oxygen is an important step in metal-catalyzed oxidation reactions and a hot subject for the research of gas-phase metal clusters.It is known that the Ag and Au clusters readily re-act with O_(2)when they have open shell electronic structures.Distinct from this,here we observed Cu_(n)^(-)(n=7−20)clusters of both open and closed shells possess high reactivity with O_(2)with few exceptions.In a combination with ab initio calculations,we demonstrate that the activation of O_(2)on the even-and odd-sized Cu_(n)^(-)clusters follows the single and double electron transfer models,respectively.Such phe-nomenon of metal clusters with different basicity to activate oxygen is enabled by the leveling effect of spin accommodation.The activity of Cu_(n)^(-)clusters is correlated to the HOMO level,and for the close-shell clusters is also governed by the vertical spin excitation energy(VSE).In encountering the attack of dioxygen,the activity of the copper cluster anions not only depends on their basicity to donate electrons,but also closely associated with the cluster sizes.Small copper clusters Cu_(n)^(-)(n=7−13)can dissociate O_(2)spontaneously,while large clusters require extra energies and display close relationship between the reaction rates and electronic vertical detachment energies(VDE).Our work illuminates a novel reaction mechanism between Cu_(n)^(-)clusters and O_(2),which sheds light in manipulating the activity and stability of coinage clusters by controlling the spin and charge states.
文摘The title compound [Cu(dtp) PPh3]2 (dtp=S2,P(OEt)2) was prepared by heating the mononuclear compound Cu(dtp)(PPh3)2 in CH3CN solution.It crystallizes in the triclinic space group P1 with parameters a=9.71 6(5),b=11.026(5),c=12.475(4) A.α=78.16(3)°,β=102. 64(4), γ=114.34(4)°,V=1178(1)A 3,Z=1,Dc=1.44 g/cm3,MoKα(λ=0.71069 A) μ=12. 48cm-1,F(000)=528.Final R=0.041.Rω= 0. 052 for 3653 unique intensity data(I≥3σ(I)).The molecule of the title compound can be viewed as a centrosymmetric dimer with two[Cu(dtp)(PPh3)] units,which are bridged by two S atoms belonging to the dtp ligands.The exact planar[Cu2S2] core and two[CuS2P] four-membered rings form a chair conformation.The Cu…Cu distance is 2.991(5) A.
文摘In this paper, single crystal EPR study of a new binuclear copper (Ⅱ) cluster compound-[Cu2(α-C(10) H7CH2CO2)4 (DMF)2]·[DMF]2·H2O](DMF= (CH3)2NCOH) at room temperature is reported. The lines of △Ms=±1 allowing transition and △M=2 forbiding transition are shown in EPR spectra. The experimental data are consistent with the calculated results by the leastsquares fitting prograrn in three principal planes of g and D tensors. The spin Hamiltonian parameters are as follows: gx=2. 1482, gy=2. 0529 ,gz=2. 3905, D= 0. 348 cm￣(-1) and E =0. 01 cm-1. The diagrams of the energy levels have been obtained when the magnetic field is oriented to three principal axes. The polycrystal EPR spectra have been measured at room temperature and 77K, respectively.and the parameters of these spectra are given (g∥= 2. 094, g⊥= 2. 425, D= 0. 37 cm-1,E=0). The parameter of the isotropic magnetic exchange interaction J=-254cm-1 is determined, and that of the anisotropic magnetic exchange J1=-153 cm-1 is calculated. The average magnetic susceptibility of the polycrystal sample χ= 1. 39 ×10-6 (c. g. s) has been measured by Faraday powder method. Thus the average magnetic mornent μ=1. 43 B. M. can be calculated. It is shown that the exchange interactions between the metal ions of the binuclear copper(Ⅱ) cluster compound are confirmed antiferromagnetic In nature.
基金financially supported by the Jiangsu Ainaji Neoenergy Science&Technology Co.,Ltd.(8507040091)the Fundamental Research Funds for the Central Universities(3207045420)the National Natural Science Foundation of China(81703366)。
文摘A novel tetranuclear copper cluster[Cu4(μ-L)6Cl2]was constructed by 2-(1H-pyrazol-3-yl)pyridine(HL)under hydrothermal conditions,and structurally concluded by single-crystal X-ray diffractions,elemental analyses and IR spectra.The title complex 1 was of triclinic system,space group■,C24H18ClCu2 N9,Mr=595.01,a=9.6497(13),b=11.4133(7),c=13.0919(15)?,α=99.166(7),β=108.707(11),γ=111.974(9)°,V=1200.7(2)?3,Z=2,Dc=1.997 g/cm^3,F(000)=706,μ(MoKα)=3.203 nm-1,Rint=0.0404,R=0.0536 and wR=0.1490 for4890 observed reflections with I>2σ(I).In this structure,complex 1 was the unimolecule with unprecedented tetranuclear cluster,which was expanded into a 2D network by wide-ranging C-H…Cl intermolecular hydrogen bonds and further exhibited a 3D supramolecular architecture based onπ-πstacking interactions.In addition,the complex was thermally stable up to 300℃and the solid state fluorescent property of 1 was examined and compared with the ligand.
文摘In this paper, single crystal EPR study of a new binuclear copper (Ⅱ) cluster compound-[Cu2(α-C(10) H7CH2CO2)4 (DMF)2]·[DMF]2·H2O](DMF= (CH3)2NCOH) at room temperature is reported. The lines of △Ms=±1 allowing transition and △M=2 forbiding transition are shown in EPR spectra. The experimental data are consistent with the calculated results by the leastsquares fitting prograrn in three principal planes of g and D tensors. The spin Hamiltonian parameters are as follows: gx=2. 1482, gy=2. 0529 ,gz=2. 3905, D= 0. 348 cm￣(-1) and E =0. 01 cm-1. The diagrams of the energy levels have been obtained when the magnetic field is oriented to three principal axes. The polycrystal EPR spectra have been measured at room temperature and 77K, respectively.and the parameters of these spectra are given (g∥= 2. 094, g⊥= 2. 425, D= 0. 37 cm-1,E=0). The parameter of the isotropic magnetic exchange interaction J=-254cm-1 is determined, and that of the anisotropic magnetic exchange J1=-153 cm-1 is calculated. The average magnetic susceptibility of the polycrystal sample χ= 1. 39 ×10-6 (c. g. s) has been measured by Faraday powder method. Thus the average magnetic mornent μ=1. 43 B. M. can be calculated. It is shown that the exchange interactions between the metal ions of the binuclear copper(Ⅱ) cluster compound are confirmed antiferromagnetic In nature.
文摘This paper obtains the lowest-energy geometric structures and the electronic and magnetic properties of small CuNiN clusters by using all-electron density functional theory. The calculated results reveal that the Cu atom prefers to occupy the apical site when N ≤ 9 and for the clusters with N = 10, the Cu atom starts to encapsulate in the cage. The CuNi7 and CuNi9 are magic clusters. The magnetism correlates closely with the symmetry of the clusters. For these clusters, the charge tends to transfer from the nickel atoms to the copper atoms. It finds that the doping of Cu atom decreases the stability of pure NiN clusters.
基金supported by the Russian Foundation for Basic Research(Grant No.13-08-00273)
文摘The process of graphene cleaning of a copper film by bombarding it with Ar_（13） clusters is investigated by the molecular dynamics method.The kinetic energies of the clusters are 5,10,20,and 30 eV and the incident angles are θ= 90°,75°,60°,45°,and 0°.It is obtained that the cluster energy should be in the interval 20 eV-30 eV for effective graphene cleaning.There is no cleaning effect at vertical incidence（θ =0°） of Ar_（13） clusters.The bombardments at 45° and 90° incident angles are the most effective on a moderate and large amount of deposited copper,respectively.
基金We are grateful to the National Natural Science Foundation of China(project 20072034)the Natural Science Foundation of Henan province and the Foundation for Young Teacher in Zhenzhou University for the financial support.
文摘A new hetero-six-nuclear cluster was synthesized and determined by X-ray diffraction technique. The four-carboxylate groups are bound to the Cu(II) atoms to form Cu(OR)4Cu paddle-wheel-type cage between two DMF as the basis for the cluster. The distance of two copper(II) atoms is 2.642 ?, and they are bridged by the carboxylate groups. A huge system plane was auto-assembled by four host molecules and two Cu (II) ions, which was observed in the crystal structure.
文摘A systematic study on the structures and electronic properties of copper clusters has been performed using the density functional theory. In the calculation, there are many isomers near the ground state for small copper clusters. Our results show that the three-dimensional isomers of copper clusters start from Cu7 cluster and then show a tendency to form more compact structures. The results of the formation energy and the second derivative of binding energy with duster size show that besides N = 8, N =11 is also a magic number. Furthermore, it is the first time to find that the ground state of 11-atom clusters is a biplanar structure as same as the 13-atom cluster. The clear odd-even alternation as cluster size for the formation energy indicates the stability of electronic close shell existed in the range studied.
基金supported by the National Natural Science Foundation of China(22178065,22078066 and U1705282).
文摘The weakness of visible and near-infrared light penetration depth limits the application of photodynamic therapy(PDT)in deep-seated tumors.Based on the high penetrability of X-rays,X-ray-induced PDT(X-PDT)is a promising new method for treating deep-seated tumors.However,it requires the development of suitable X-ray-induced sensitizers that could employ X-ray energy to produce reactive oxygen species(ROS)efficiently.In this study,a novel X-rayinduced sensitizer(NanoSRF)was developed through a microemulsion method,in which copper iodine cluster compound Cu_(2)I_(2)(tpp)2(2,5-dm-pz)(CIP)and rose bengal(RB)worked as scintillator and photosensitizer,respectively.CIP was synthesized by a simple mechanical grinding method,and subsequently folic acid(FA)-modified albumin was introduced to enable its alliance with RB.NanoSRF exhibited excellent dispersion stability and generated a large amount of ROS under X-ray irradiation.The results of in vitro studies demonstrated its high selectivity for FA receptor-positive cancer cells.Following systemic administration,NanoSRF accumulated in H22 tumors of xenograft-bearing mice,and Xray irradiation(5.46 Gy)induced a significant inhibition rate of 96.7%in tumor growth.This study pioneers the use of copper iodide cluster as a scintillator in X-PDT,presenting new possibilities for designing scintillators with exceptional X-ray absorption and efficient X-PDT capabilities.
基金supported by the National Natural Science Foundation of China(92061201,21825106,22371264,22301283)the Excellent Young Scientist Fundation of Henan Province(202300410374)+1 种基金the Program for Science&Technology Innovation Talents in Universities of Henan Province(22HASTIT002)Zhongyuan Thousand Talents(Zhongyuan Scholars)Program of Henan Province(234000510007)。
文摘Stimuli-responsive luminescent materials have attracted significant attention in the development of smart photoactive materials for both fundamental research and technological applications.In this work,a new copper iodide cluster(1)with aggregationinduced emission(AIE)characteristic,was obtained combining Cu_(4)I_(4) core with rhodamine B derivative ligand.1 has reversible and distinct multi-stimuli-responsive luminescence for external temperature,volatile organic compound,and mechanical force.Significantly,1 exhibited unusual large blue shift(84 nm)after being ground,which originated from the change of intermolecular interactions.Moreover,1 exhibits high oxygen quenching efficiency for 82.2% at 1 bar.Mechanistic studies showed that the multi-stimuli-responsive luminescence properties of 1 can be attributed to the regulation of cluster-centered luminescence process,metal-to-ligand charge transfer process,halide-to-metal charge transfer luminescence process and aggregationinduced barrier to oxygen process.This work not only reports an AIE copper iodide cluster,but also provides a new strategy to develop multi-stimuli-responsive luminescence materials.
基金Supported by the National Natural Science Foundation of China(No.20771073)
文摘Three crystal architectures, including one organic compound of benzoyl peroxide（Ⅰ） and two clusters of tri-iron（Ⅲ） and bi-cupper（Ⅱ） with benzoic ligands（2 and 3）, were self-assembled by an in situ redox way of benzoyl peroxide oxidants reacting with Mo, Fe and Cu powders, respectively. X-ray crystallographic results show that both the asymmetry tri-iron（Ⅲ） cluster and the benzoylperoxide crystal architecture（2 and 1） with complicated 3D networks were constructed by intermolecular hydrogen-bonding interactions. Contrarily, the symmetrical bi-copper（Ⅱ） cluster crystal architecture（3）, only with π-π stacking between paralleled phenyl groups and without any intermolecular hydrogen-bonding interactions, only presented an 1D zigzag chain along the a-axis.
