Copolymerization of propylene oxide (PO) and ethylene oxide (EO) using double metal cyanide (DMC) complex as the catalyst was carried out. The structure of random copolymers was confirmed by C-13-NMR and IR spectra. H...Copolymerization of propylene oxide (PO) and ethylene oxide (EO) using double metal cyanide (DMC) complex as the catalyst was carried out. The structure of random copolymers was confirmed by C-13-NMR and IR spectra. H-1-NMR analysis shows that the EO content in the copolymer is the same as that in the initial monomer feed. Moderate molecular weight copolymers with various EO content were obtained and their values of molecular weight distribution (MWD) fell in the range of 1.21-1.55. It was found that the molecular weight of copolymers is controlled by the mass ratio of EO+PO to initiator moles used, The reaction rate as well as polymer yield decrease with increasing EO content in the feed composition.展开更多
In this manuscript, we have demonstrated the delicate design and synthesis of bimetallic oxides nanoparticles derived from metal–oleate complex embedded in 3D graphene networks(MnO/CoMn_2O_4 GN), as an anode mater...In this manuscript, we have demonstrated the delicate design and synthesis of bimetallic oxides nanoparticles derived from metal–oleate complex embedded in 3D graphene networks(MnO/CoMn_2O_4 GN), as an anode material for lithium ion batteries. The novel synthesis of the MnO/CoMn_2O_4 GN consists of thermal decomposition of metal–oleate complex containing cobalt and manganese metals and oleate ligand, forming bimetallic oxides nanoparticles, followed by a selfassembly route with reduced graphene oxides. The MnO/CoMn_2O_4 GN composite, with a unique architecture of bimetallic oxides nanoparticles encapsulated in 3D graphene networks, rationally integrates several benefits including shortening the di usion path of Li^+ ions, improving electrical conductivity and mitigating volume variation during cycling. Studies show that the electrochemical reaction processes of MnO/Co Mn_2O_4 GN electrodes are dominated by the pseudocapacitive behavior, leading to fast Li^+ charge/discharge reactions. As a result, the MnO/CoMn_2O_4 GN manifests high initial specific capacity, stable cycling performance, and excellent rate capability.展开更多
This is a mini-review-like article including our recent results and methods for （new） metal oxides and （previously reported） composite materials composed of metal complexes and metal oxides for comparison to enhan...This is a mini-review-like article including our recent results and methods for （new） metal oxides and （previously reported） composite materials composed of metal complexes and metal oxides for comparison to enhance anisotropic structural changes intentionally. Some complex inorganic oxides are known that they may be promising color materials （absorbing visible light of certain wavelengths region） having potential application for environmentally benign catalysts, for example, photocatalysts. Chiral copper（Ⅱ） complexes having bidentate amine ligands （[CuL2]2＋） can be acted as cationic building blocks of bimetallic metal complexes. We have prepared some chiral bimetallic complexes with various anionic metal complexes such as [PtCl4]2-, [M02O7]2 and Mn12 clusters （typical single-molecule magnets） which characterized by means of solid-state electronic and CD （circular dichroism） spectra, IR （infrared） spectra, synchrotron XRD （X-ray diffraction） and XAS （soft X-ray absorption spectroscopy）. By sintering these precursor chiral bimetallic complexes, we have prepared complex inorganic oxides from them. The IR spectra indicated substituting metal-ligand bonds and losing organic moieties. The XRD pattern indicated complete changes of crystal structures. The XAS revealed replacing coordination atoms as well as oxidation of valences of metal ions. Furthermore, we will also investigate possibility of patterning by homogeneous precipitation method as bimetallic complexes to prepare desirable complex inorganic oxides.展开更多
Dibenzoyl peroxide undergoes oxidative addition on metallic copper powder with 2,2′-bipyridine(or imidazole)in a mixed solvent(methanol and tetrahydrofuran),and affords the Cu(Ⅱ)complexes-[Cu(Ce(C_6H_5COO)_2(2,2'...Dibenzoyl peroxide undergoes oxidative addition on metallic copper powder with 2,2′-bipyridine(or imidazole)in a mixed solvent(methanol and tetrahydrofuran),and affords the Cu(Ⅱ)complexes-[Cu(Ce(C_6H_5COO)_2(2,2'-bipy)]H_2O(1) and[Cu(C_6H_5COO)_2(C_3H_4N_2)_2](2).The structure was solved by direct methods and Fourier synthesis.C_(24)H_(20)N_2O_5Cu (1),Mr=479.78,space group P2(1)/c,a=6.986(7), b=18.833(I),c=17.021(3),α=γ=90°,Z=4,V=2218.1~3,Dc=1.443g/cm\+3,R=0.055 Rw=0.062.Complex(2),C_(20)H_(18)N_4O_4Cu(2),Mr=441.74,space group P2(1)/n,a=8.699(4), b=9.840(6),c=12.399(5),α=γ=90°,β=100.8°,Z=4,V=1010.9~3,Dc=1.654g/cm\+3,R=0.055, Rw=0.062.展开更多
Heavy metal complexes with high mobility are widely distributed in wastewater from modern industries,which are mo re stable and refracto ry than free heavy metal ions.Their re movals from wastewater draw increasing at...Heavy metal complexes with high mobility are widely distributed in wastewater from modern industries,which are mo re stable and refracto ry than free heavy metal ions.Their re movals from wastewater draw increasing attentions and various technologies have been developed,among which advanced oxidation processes(AOPs)are more effectively and promising.Progresses on five representative types of AOPs,including Fenton(like)oxidation,electrochemical oxidation,photocatalytic oxidation,ozonation and discharge plasma oxidation for heavy metal complexe s degradation are summarized in this review.Their rationales,advantages,applications,challenges and prospects are introduced independently.Combinations among these AOPs,such as electrochemical Fenton oxidation and photoelectrocatalytic oxidation,are also comprehensively highlighted.Future efforts should be made to reduce acid requirement and scale up for practical applications of AOPs for heavy metal complex degradation efficiently and cost-effectively.展开更多
The simultaneous electro-oxidation of Ni(Ⅱ)-citrate and electrodeposition recovery of nickel metal were attempted in a combined electro-oxidation-electrodeposition reactor with a boron-doped diamond(BDD)anode and a p...The simultaneous electro-oxidation of Ni(Ⅱ)-citrate and electrodeposition recovery of nickel metal were attempted in a combined electro-oxidation-electrodeposition reactor with a boron-doped diamond(BDD)anode and a polished titanium cathode.Effects of initial nickel citrate concentration,current density,initial p H,electrode spacing,electrolyte type,and initial electrolyte dosage on electrochemical performance were examined.The efficiencies of Ni(Ⅱ)-citrate removal and nickel metal recovery were determined to be 100%and over 72%,respectively,under the optimized conditions(10 m A/cm^(2),pH 4.09,80 mmol/L Na_(2)SO_(4),initial Ni(Ⅱ)-citrate concentration of 75 mg/L,electrode spacing of 1 cm,and 180 min of electrolysis).Energy consumption increased with increased current density,and the energy consumption was 0.032 kWh/L at a current density of 10 m A/cm^(2)(pH 6.58).The deposits at the cathode were characterized by scanning electron microscopy(SEM),energy-dispersive spectrometry(EDS),X-ray diffraction(XRD),and X-ray photoelectron spectroscopy(XPS).These characterization results indicated that the purity of metallic nickel in cathodic deposition was over 95%.The electrochemical system exhibited a prospective approach to oxidize metal complexes and recover metallic nickel.展开更多
Seven kinds of Schiff base metal complexes(C1-C7)were synthesized by the reaction of substituted salicylaldehyde Schiff base with cobalt nitrate,nickel nitrate,and copper nitrate,respectively.The oxygen carrying perfo...Seven kinds of Schiff base metal complexes(C1-C7)were synthesized by the reaction of substituted salicylaldehyde Schiff base with cobalt nitrate,nickel nitrate,and copper nitrate,respectively.The oxygen carrying performance,and the catalytic property of complexes for the oxidation of model sulfides 1-hexanethiol,dibutyl sulfide,and 2-methylthiophene along with their influencing factors were explored,while the oxidized products of the model sulfides were also analyzed and characterized.The results show that the catalytic oxidation property of the complexes is determined by their oxygen carrying performance and solubility in n-octane.The oxygen carrying performance of the complexes is mainly affected by the central ion species,the electronic effects,and the spatial effects of the substituents as well as the degree of conjugation.More specifically,the oxygen carrying performance can be improved by enhancing the oxygenation capacity of the central metal ions,increasing the electron donating ability of the ligand substituent,and diminishing the steric hindrance as well as extending the conjugated chain.Complexes C7 were found to be with high oxygen carrying capacity and high solubility in n-octane,which shows the best catalytic oxidation property,and the oxidation conversion rates for 1-hexylthiol,dibutyl sulfide,and 2-methylthiophene are 74.2%,65.1%,and 22.7%,respectively.Upon using the oxidation catalyst of Schiff base metal complexes,three sulfides can be oxidized by oxygen to form sulfones and sulfoxides.1-Hexanethiol and dibutyl sulfide will continue to be oxidized to form sulfates and sulfites.展开更多
In some industrial wastewater,heavy metals combine with organic complexing agents to form heavy metal complexes(HMCs).These HMCs can be difficult to decompose and remove through conventional techniques due to their hi...In some industrial wastewater,heavy metals combine with organic complexing agents to form heavy metal complexes(HMCs).These HMCs can be difficult to decompose and remove through conventional techniques due to their higher stability than free heavy metal ions.In recent years,persulfate based advanced oxidation processes(PS-based AOPs)have been recognized as a viable technique for HMCs degradation.Nevertheless,a comprehensive and in-depth understanding of the relevant HMCs decomplexation mechanisms in PS-based AOPs is still lacking.This review delineates the current progress of HMCs decomplexation in PS-based AOPs.We discuss the distinctions between the two widely used oxidant types in PS-based AOPs techniques.Moreover,we summarize and highlight the decomplexation mechanisms based on electron and energy transfer,and degradation pathways of HMCs.We also emphasize the effects of environmental water constituents,namely p H,inorganic ions,and natural organic matter(NOM),on HMCs decomplexation.Ultimately,we identify the existing challenges and perspectives that will steer the direction of advancing PS-based AOPs to remove HMCs.展开更多
Hydrotalcites known as anionic clays are found in nature. Hydrotalcites, hydrotalcite-like compounds, and calcined hydrotalcites (as mixed or complex oxides) as highly active, selective catalysts play an important rol...Hydrotalcites known as anionic clays are found in nature. Hydrotalcites, hydrotalcite-like compounds, and calcined hydrotalcites (as mixed or complex oxides) as highly active, selective catalysts play an important role in many base/catalyzed reactions. Mg/Al hydrotalcite (MAH) as precursor was used to prepare Mg/Al metal complex oxides (MAO), used as epoxidation catalysts in the current research. In this paper, some primary physical and catalytic properties of MAH and MAO were investigated. The results indicated that the qualified MAH (Mg/Al mol ratio of 3) can be achieved when the suspension was crystallized under 80°C for 16h, and after being filtered, dried at 100 °C for 5h in a oven. MAO was prepared by calcining MAH for 4h in a muffle furnace, and calcination temperature was determined to be 500 °C by a differential scanning calorimeter (DSC). Crystal structure and parameters of MAH and MAO were characterized by X/ray diffraction (XRD), good crystal structure was observed and typical peaks of MAH were detected when 2θ was at 11.5 (003), 23.0 (006), 35.0 (009), and 61.0 (110), respectively. The morphology of calcined precursor, i.e. MAO, was investigated with scanning electron microscopy (SEM);the finer lamellar structure and smaller average size of 3μm was observed. Molding research was performed and confirmed by SEM, the results indicated that the surface bulge and cavity with size of several micrometers were increased, which simultaneously suggested the increasing of specific surface area. The catalytic activity of molding MAO was finally examined by using octanol as starting reagent and ethylene oxide as reactant, and narrower molecular distribution was observed comparing with the traditional catalyst-KOH.展开更多
We report in situ doping of brushite on zinc manganese oxide（ZMO）, fabricated by calcining a Mn（II） oxalate‐impregnated metal‐organic framework. The doping process was conducted in com‐bination with the photoca...We report in situ doping of brushite on zinc manganese oxide（ZMO）, fabricated by calcining a Mn（II） oxalate‐impregnated metal‐organic framework. The doping process was conducted in com‐bination with the photocatalytic water oxidation reaction which was catalyzed by ZMO in neutral phosphate‐buffered aqueous solution containing [Ru（bpy）3]^2＋‐Na2S2O8 and calcium（II） triflate salt, exhibiting greatly enhanced water oxidation performance with optimized turnover frequency of 0.18 mmol（O2） mol（Mn）^（–1） s^（–1）. Different analytical techniques indicated that photodeposited calci‐um‐phosphate（CaP） acted as a co‐catalyst to promote the O2 evolution activity of ZMO. This system involved the use of manganese oxide and calcium ion, and the operation was conducted under am‐bient temperature and neutral conditions, thus, it efficiently mimicked the oxygen‐evolving complex in photosystem II.展开更多
Studies were carried out to determine the activity of complexes of the essential amino acids DL-Lysine and L-Methionine with heavy metals in the oxidation of cyclohexene with tert-butylhydroperoxide in toluene at 80&#...Studies were carried out to determine the activity of complexes of the essential amino acids DL-Lysine and L-Methionine with heavy metals in the oxidation of cyclohexene with tert-butylhydroperoxide in toluene at 80°C. All complexes were prepared through interaction of metal ions and DL-Lysine and L-Methionine at room temperature in aqueous solutions. Only the complexes of Mo and W were obtained from acidic aqueous solution. These complexes were characterized by FT-IR, Moessbauer spectroscopy and EPR analysis. The products of the oxidation reactions were identified by GC/MS analysis. The complexes of Mo and V showed the best activity in the epoxidation reaction of cyclohexene in comparison with other complexes, such as Ni, Mn, Zn, Co, Cu, Cr, Fe and W. Using semi-empirical quantum-chemistry methods, the full energy of the Mo complexes was calculated and their probable structure is presented.展开更多
Ferrate（VI） was employed for the oxidation of cyanide （CN） and simultaneous removal of copper or nickel in the mixed/complexed systems of CN-Cu, CN-Ni, or CN-Cu-Ni. The degradation of CN （1.00 mmol/L） and remova...Ferrate（VI） was employed for the oxidation of cyanide （CN） and simultaneous removal of copper or nickel in the mixed/complexed systems of CN-Cu, CN-Ni, or CN-Cu-Ni. The degradation of CN （1.00 mmol/L） and removal of Cu （0.095 mmol/L） were investigated as a function of Fe（Ⅵ） doses from 0.3-2.00 mmol/L at pH 10.0. It was found that Fe（Ⅵ） could readily oxidize CN and the reduction of Fe（Ⅵ） into Fe（Ⅲ） might serve efficiently for the removal of free copper ions. The increase in Fe（Ⅵ） dose apparently favoured the CN oxidation as well as Cu removal. Moreover, the pH dependence study （pH 10.0-13.0） revealed that the oxidation of CN was almost unaffected in the studied pH range （10.0-13.0）, however, the maximum removal efficiency of Cu was obtained at pH 13.0. Similarly, treatment was carded out for CN-Ni system having the initial Ni concentration of 0.170 mmol/L and CN concentration of 1.00 mmol with Fe（Ⅵ） dose 2.00 mmol at various pH values （10.0-12.0）. Results showed a partial oxidation of CN and partial removal of Ni. It can be observed that Fe（Ⅵ） can partially degrade the CN-Ni complex in this pH range. Further, Fe（Ⅵ） was applied for the treatment of simulated industrial waste/effluent waters treatment containing CN, Cu, and Ni.展开更多
Photocatalytic water oxidation based on semiconductors usually suffers from poor charge transfer from the bulk to the interface,which is necessary for oxygen generation.Here,we construct a hybrid artificial photosynth...Photocatalytic water oxidation based on semiconductors usually suffers from poor charge transfer from the bulk to the interface,which is necessary for oxygen generation.Here,we construct a hybrid artificial photosynthesis system for photocatalytic water oxidation.The system consists of BiVO4as the light harvester,a transitional metal complex(M(dca)2,M=Co,Ni,dca:dicyanamide)as the water oxidation catalyst,and S2O82?as a sacrificial electron acceptor.The system exhibits enhanced oxygen evolution activity when M(dca)2is introduced.The BiVO4/Co(dca)2and Bi‐VO4/Ni(dca)2systems exhibit excellent oxygen evolution rates of508.1and297.7μmol/(h·g)compared to the pure BiVO4which shows a photocatalytic oxygen evolution rate of252.2μmol/(h·g)during6h of photocatalytic reaction.Co(dca)2is found to be more effective than Ni(dca)2as a water oxidation catalyst.The enhanced photocatalytic performance is ascribed to the M(dca)2‐engineered BiVO4/electrolyte interface energetics,and to the M(dca)2‐catalyzed surface water oxidation.These two factors lead to a decrease in the energy barrier for hole transfer from the bulk to the surface of BiVO4,which promotes the water oxidation kinetics.展开更多
The cheap raw rice husks and the products of their thermal degradation WRHA （white rice husk ash） and BRHA （black rice husk ash）, after vigorously grounding and mixing, can successfully be used as a catalyst suppo...The cheap raw rice husks and the products of their thermal degradation WRHA （white rice husk ash） and BRHA （black rice husk ash）, after vigorously grounding and mixing, can successfully be used as a catalyst support to replace the existing expensive ones. The aim of the present research is to prepare new metal-immobilized complexes based on rice husks and to study their catalytic activity in the oxidation of cyclohexene with tert-butylhydroperoxide. The corresponding metal complexes were obtained by interaction of RRH （raw rice husks） or thermally treated WRHA in air atmosphere. The complexes were obtained from aqueous solutions of various salts such as FeCl2.4H2O, COCl2.6H2O, VOSO4.5H2O and Na2MoO4.2H2O at room temperature. The rice husks-supported metal complexes were identified by infrared spectroscopy. The structure of the iron-containing polymeric materials was evaluated by Mossbauer spectroscopy. The catalytic activity of the molybdenum-containing complex catalyst in the principal epoxidation reaction was higher than that of the vanadium-containing one, whereas, the opposite order of activities was found for the side reaction of allylic hydroxylation of cyclohexene. Under selected reaction conditions, the yields of the principal reaction products cyclohexene oxide （1,2-epoxycyclohexane） and 2-cyclohexene-1-ol were 36.4% and 22.7%, respectively.展开更多
Chloromethylated styrene-divinylbenzene copolymer beads with 8% crosslink were chemically modified by reaction with Ethylenediaminetetraaceticacid leading to the incorporation of nitrogen as ligating site on the surfa...Chloromethylated styrene-divinylbenzene copolymer beads with 8% crosslink were chemically modified by reaction with Ethylenediaminetetraaceticacid leading to the incorporation of nitrogen as ligating site on the surface of the polymer. The polymeric ligand on treatment with a solution of Copper chloride gave the corresponding metal complex. The polymer supported Cu(II) complex was characterized by elemental analyses, IR,GC-MS, scanning electron micrographs (SEM). The oxidation of various alcohols such as benzyl alcohol, 2-butanol, and 2-propanol was investigated using the supported metal complexes in presence of molecular oxygen as the oxidant. The swelling studies were done by using different solvents. Kinetic data indicate that the catalysts could be recycled without significant degradation of polymer matrix.展开更多
An “experimental” valence state of metal complexes is sometime different from the “formal” oxidation state, especially in the species having redox active ligands. This difference can be seen in biological system, ...An “experimental” valence state of metal complexes is sometime different from the “formal” oxidation state, especially in the species having redox active ligands. This difference can be seen in biological system, such as iron(IV)-porphyrin π-cation radical in some heme proteins and copper(II)-phenoxyl radical in galactose oxidase (GO). Although structural characterizations of these species by X-ray diffraction methods have been rare due to their stability, some artificial metal-phenoxyl radical complexes have been synthesized and successfully characterized by X-ray crystal structure. In this review, syntheses and X-ray crystal structures of the one-electron oxidized metal-phenolate complexes, metal- phenoxyl radical, and high-valent metal phenolate species are discussed.展开更多
The optimum reaction conditions of the oxidative polycondensation of 2-(thien-2-yl-methylene)aminophenol (2-TMAP) has been accomplished by using air O_2,H_2O_2 and NaOCl oxidants in an aqueous alkaline medium between...The optimum reaction conditions of the oxidative polycondensation of 2-(thien-2-yl-methylene)aminophenol (2-TMAP) has been accomplished by using air O_2,H_2O_2 and NaOCl oxidants in an aqueous alkaline medium between 20℃and 90℃.The structures of the monomer and oligomer were confirmed by FT-IR,UV-Vis,~1H-NMR and ^(13)C-NMR and elemental analysis.TGA-DTA,size exclusion chromatography(SEC) techniques and solubility tests were applied for characterization.The ~1H-NMR and ^(13)C-NMR data show that the polymeriz...展开更多
Integrating polyoxometalate and catalytically active metal centers with multiple chemical states provides a promising approach for the design of efficient catalysts for benzyl C-H bond oxidation.Herein,two synergistic...Integrating polyoxometalate and catalytically active metal centers with multiple chemical states provides a promising approach for the design of efficient catalysts for benzyl C-H bond oxidation.Herein,two synergistic crystalline catalysts assembled with the Wells-Dawson-type[P_(2)W_(18)O_(62)]^(6−)cluster and heterovalent Cu complexes were synthesized for benzylic C-H oxidation,with the formulae[Cu_(3)^(Ⅰ)Cu_(3)^(Ⅱ)(μ_(2)-OH)6(H_(2)O)_(1.5)(DTAB)_(3)][H_(3)P_(2)W_(18)O_(62)]·18H_(2)O(1)and[Cu_(2)^(Ⅰ)(DTAB)2]{[Cu_(2)^(Ⅰ)(μ_(3)-Cl)][Cu_(4)^(Ⅰ)(μ_(3)-Cl)](DTAB)_(4)}[P_(2)W18O62]·9H_(2)O(2)(DTAB=1,4-di[4H-1,2,4-triazol-4-yl]-benzene).Compound 1 possesses 2-D copper-ligand cationic layers composed of heterovalent[Cu_(3)^(Ⅰ)Cu_(3)^(Ⅱ)(μ_(2)-OH)_(6)]^(3+)chains,in which the protonated[H_(3)P_(2)W_(18)O_(62)]^(3−)polyanions intercalate between them.Compound 2 has a sandwich-like 2-D lamellar structure consisting of three copper-organic units(binuclear{Cu_(2)^(Ⅰ)},trinuclear{Cu_(3)^(Ⅰ)Cl},and tetranuclear{Cu_(4)^(Ⅰ)Cl}units),in which the[P_(2)W_(18)O_(62)]^(6−)clusters are encapsulated.The heterovalent copper species and[P_(2)W_(18)O_(62)]^(6−)clusters within the two compounds make them dual-site synergistic catalysts and the roles of each component in the selective oxidation of benzyl C-H bonds were explored.Using the oxidation of diphenylmethane(DPM)as a model reaction,the two synergistic catalysts displayed ca.95%and 92%DPM conversion with>98%benzophenone(BP)selectivity within 8 h.Mechanism investigations revealed that both copper sites and polyanionic clusters as active centers corporately promoted the adsorption and activation of the t-BuOOH oxidant in the radical-mediated DPM oxidation reaction via coordination and hydrogen bonding interactions to generate active t-BuO·and·OH radicals,accelerating the oxidation of DPM and the formation of BP.Additionally,this kind of synergistic catalyst showcased excellent substrate compatibility and recoverability,as well as robust structural stability.This work affords a promising approach for designing efficient POM-based crystalline catalysts for benzyl C-H bond oxidation.展开更多
Photodynamic therapy(PDT)holds significant promise as a medical treatment approach in human diseases.Recently,PDT has received attention to harness light-induced reactive oxygen species and,subsequently,modify amyloid...Photodynamic therapy(PDT)holds significant promise as a medical treatment approach in human diseases.Recently,PDT has received attention to harness light-induced reactive oxygen species and,subsequently,modify amyloidogenic peptides implicated in human degenerative diseases.Here we report a series of strategically designed photosensitizers comprised of boron-dipyrromethene(BODIPY)scaffolds conjugated with transition metal ions.Our comprehensive biophysical and biochemical investigations demonstrate the efficacy of the photosensitizers in generating reactive oxygen species(ROS),such as singlet oxygen(^(1)O_(2)),superoxide anion radicals(O_(2)^(·-)),and hydroxyl radicals(·OH),upon photoactivation at a relatively longer wavelength,resulting in the oxidation of amyloid-β(Aβ).Consequently,the induced oxidation brings about significant alterations in the aggregation pathways and morphologies of the peptides.Moreover,Aβspecies produced by treating the metal complex,Ir-BDP,exhibiting the highest ROS generation efficiency and photoactivation,are less toxic than the complex-free Aβspecies.Overall,our findings underscore the therapeutic potential of these newly designed photosensitizers in addressing amyloid-related diseases.展开更多
文摘Copolymerization of propylene oxide (PO) and ethylene oxide (EO) using double metal cyanide (DMC) complex as the catalyst was carried out. The structure of random copolymers was confirmed by C-13-NMR and IR spectra. H-1-NMR analysis shows that the EO content in the copolymer is the same as that in the initial monomer feed. Moderate molecular weight copolymers with various EO content were obtained and their values of molecular weight distribution (MWD) fell in the range of 1.21-1.55. It was found that the molecular weight of copolymers is controlled by the mass ratio of EO+PO to initiator moles used, The reaction rate as well as polymer yield decrease with increasing EO content in the feed composition.
基金financial support from National Natural Science Foundation of China (No. 21373006 and No. 51801030)the Science and Technology Program of Suzhou (SYG201732)+4 种基金the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)the project of Scientific and Technologic Infrastructure of Suzhou (SZS201708)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China (17KJB430029)One-hundred Young Talents (Class A) of Guangdong University of Technology (No. 220413198)Natural Science Foundation of Guangdong Providence (No. 2018A030310571)
文摘In this manuscript, we have demonstrated the delicate design and synthesis of bimetallic oxides nanoparticles derived from metal–oleate complex embedded in 3D graphene networks(MnO/CoMn_2O_4 GN), as an anode material for lithium ion batteries. The novel synthesis of the MnO/CoMn_2O_4 GN consists of thermal decomposition of metal–oleate complex containing cobalt and manganese metals and oleate ligand, forming bimetallic oxides nanoparticles, followed by a selfassembly route with reduced graphene oxides. The MnO/CoMn_2O_4 GN composite, with a unique architecture of bimetallic oxides nanoparticles encapsulated in 3D graphene networks, rationally integrates several benefits including shortening the di usion path of Li^+ ions, improving electrical conductivity and mitigating volume variation during cycling. Studies show that the electrochemical reaction processes of MnO/Co Mn_2O_4 GN electrodes are dominated by the pseudocapacitive behavior, leading to fast Li^+ charge/discharge reactions. As a result, the MnO/CoMn_2O_4 GN manifests high initial specific capacity, stable cycling performance, and excellent rate capability.
文摘This is a mini-review-like article including our recent results and methods for （new） metal oxides and （previously reported） composite materials composed of metal complexes and metal oxides for comparison to enhance anisotropic structural changes intentionally. Some complex inorganic oxides are known that they may be promising color materials （absorbing visible light of certain wavelengths region） having potential application for environmentally benign catalysts, for example, photocatalysts. Chiral copper（Ⅱ） complexes having bidentate amine ligands （[CuL2]2＋） can be acted as cationic building blocks of bimetallic metal complexes. We have prepared some chiral bimetallic complexes with various anionic metal complexes such as [PtCl4]2-, [M02O7]2 and Mn12 clusters （typical single-molecule magnets） which characterized by means of solid-state electronic and CD （circular dichroism） spectra, IR （infrared） spectra, synchrotron XRD （X-ray diffraction） and XAS （soft X-ray absorption spectroscopy）. By sintering these precursor chiral bimetallic complexes, we have prepared complex inorganic oxides from them. The IR spectra indicated substituting metal-ligand bonds and losing organic moieties. The XRD pattern indicated complete changes of crystal structures. The XAS revealed replacing coordination atoms as well as oxidation of valences of metal ions. Furthermore, we will also investigate possibility of patterning by homogeneous precipitation method as bimetallic complexes to prepare desirable complex inorganic oxides.
文摘Dibenzoyl peroxide undergoes oxidative addition on metallic copper powder with 2,2′-bipyridine(or imidazole)in a mixed solvent(methanol and tetrahydrofuran),and affords the Cu(Ⅱ)complexes-[Cu(Ce(C_6H_5COO)_2(2,2'-bipy)]H_2O(1) and[Cu(C_6H_5COO)_2(C_3H_4N_2)_2](2).The structure was solved by direct methods and Fourier synthesis.C_(24)H_(20)N_2O_5Cu (1),Mr=479.78,space group P2(1)/c,a=6.986(7), b=18.833(I),c=17.021(3),α=γ=90°,Z=4,V=2218.1~3,Dc=1.443g/cm\+3,R=0.055 Rw=0.062.Complex(2),C_(20)H_(18)N_4O_4Cu(2),Mr=441.74,space group P2(1)/n,a=8.699(4), b=9.840(6),c=12.399(5),α=γ=90°,β=100.8°,Z=4,V=1010.9~3,Dc=1.654g/cm\+3,R=0.055, Rw=0.062.
基金the National Natural Science Foundation of China(NSFC)(No.41672237)the Beijing Natural Science Foundation(No.8192040)。
文摘Heavy metal complexes with high mobility are widely distributed in wastewater from modern industries,which are mo re stable and refracto ry than free heavy metal ions.Their re movals from wastewater draw increasing attentions and various technologies have been developed,among which advanced oxidation processes(AOPs)are more effectively and promising.Progresses on five representative types of AOPs,including Fenton(like)oxidation,electrochemical oxidation,photocatalytic oxidation,ozonation and discharge plasma oxidation for heavy metal complexe s degradation are summarized in this review.Their rationales,advantages,applications,challenges and prospects are introduced independently.Combinations among these AOPs,such as electrochemical Fenton oxidation and photoelectrocatalytic oxidation,are also comprehensively highlighted.Future efforts should be made to reduce acid requirement and scale up for practical applications of AOPs for heavy metal complex degradation efficiently and cost-effectively.
基金supported by Major Science and Technology Program for Water Pollution Control and Treatment in China(No.2017ZX07202-001-007)the National Science Fund for Distinguished Young Scholars(No.51625801)+4 种基金the Guangdong Innovation Team Project for Colleges and Universities(No.2016KCXTD023)Guangdong Provincial Science and Technology Project(No.2017A020216014)the National Science Fund,China(No.21777106)Pearl River S&T Noval Program of Guangzhou,China(No.201710010065)the key projects of Dongguan social science and technology development plan(No.2019507140204)。
文摘The simultaneous electro-oxidation of Ni(Ⅱ)-citrate and electrodeposition recovery of nickel metal were attempted in a combined electro-oxidation-electrodeposition reactor with a boron-doped diamond(BDD)anode and a polished titanium cathode.Effects of initial nickel citrate concentration,current density,initial p H,electrode spacing,electrolyte type,and initial electrolyte dosage on electrochemical performance were examined.The efficiencies of Ni(Ⅱ)-citrate removal and nickel metal recovery were determined to be 100%and over 72%,respectively,under the optimized conditions(10 m A/cm^(2),pH 4.09,80 mmol/L Na_(2)SO_(4),initial Ni(Ⅱ)-citrate concentration of 75 mg/L,electrode spacing of 1 cm,and 180 min of electrolysis).Energy consumption increased with increased current density,and the energy consumption was 0.032 kWh/L at a current density of 10 m A/cm^(2)(pH 6.58).The deposits at the cathode were characterized by scanning electron microscopy(SEM),energy-dispersive spectrometry(EDS),X-ray diffraction(XRD),and X-ray photoelectron spectroscopy(XPS).These characterization results indicated that the purity of metallic nickel in cathodic deposition was over 95%.The electrochemical system exhibited a prospective approach to oxidize metal complexes and recover metallic nickel.
基金This work was supported by the National Natural Science Foundation of China(No.21576292).
文摘Seven kinds of Schiff base metal complexes(C1-C7)were synthesized by the reaction of substituted salicylaldehyde Schiff base with cobalt nitrate,nickel nitrate,and copper nitrate,respectively.The oxygen carrying performance,and the catalytic property of complexes for the oxidation of model sulfides 1-hexanethiol,dibutyl sulfide,and 2-methylthiophene along with their influencing factors were explored,while the oxidized products of the model sulfides were also analyzed and characterized.The results show that the catalytic oxidation property of the complexes is determined by their oxygen carrying performance and solubility in n-octane.The oxygen carrying performance of the complexes is mainly affected by the central ion species,the electronic effects,and the spatial effects of the substituents as well as the degree of conjugation.More specifically,the oxygen carrying performance can be improved by enhancing the oxygenation capacity of the central metal ions,increasing the electron donating ability of the ligand substituent,and diminishing the steric hindrance as well as extending the conjugated chain.Complexes C7 were found to be with high oxygen carrying capacity and high solubility in n-octane,which shows the best catalytic oxidation property,and the oxidation conversion rates for 1-hexylthiol,dibutyl sulfide,and 2-methylthiophene are 74.2%,65.1%,and 22.7%,respectively.Upon using the oxidation catalyst of Schiff base metal complexes,three sulfides can be oxidized by oxygen to form sulfones and sulfoxides.1-Hexanethiol and dibutyl sulfide will continue to be oxidized to form sulfates and sulfites.
基金financially supported by National Natural Science Foundation of China(Nos.U22A20403,22006047)Natural Science Foundation of Hebei Province(Nos.E2021203140,B2021203016)Hebei Industrial Innovation and Entrepreneurship team(No.215A7608D)。
文摘In some industrial wastewater,heavy metals combine with organic complexing agents to form heavy metal complexes(HMCs).These HMCs can be difficult to decompose and remove through conventional techniques due to their higher stability than free heavy metal ions.In recent years,persulfate based advanced oxidation processes(PS-based AOPs)have been recognized as a viable technique for HMCs degradation.Nevertheless,a comprehensive and in-depth understanding of the relevant HMCs decomplexation mechanisms in PS-based AOPs is still lacking.This review delineates the current progress of HMCs decomplexation in PS-based AOPs.We discuss the distinctions between the two widely used oxidant types in PS-based AOPs techniques.Moreover,we summarize and highlight the decomplexation mechanisms based on electron and energy transfer,and degradation pathways of HMCs.We also emphasize the effects of environmental water constituents,namely p H,inorganic ions,and natural organic matter(NOM),on HMCs decomplexation.Ultimately,we identify the existing challenges and perspectives that will steer the direction of advancing PS-based AOPs to remove HMCs.
文摘Hydrotalcites known as anionic clays are found in nature. Hydrotalcites, hydrotalcite-like compounds, and calcined hydrotalcites (as mixed or complex oxides) as highly active, selective catalysts play an important role in many base/catalyzed reactions. Mg/Al hydrotalcite (MAH) as precursor was used to prepare Mg/Al metal complex oxides (MAO), used as epoxidation catalysts in the current research. In this paper, some primary physical and catalytic properties of MAH and MAO were investigated. The results indicated that the qualified MAH (Mg/Al mol ratio of 3) can be achieved when the suspension was crystallized under 80°C for 16h, and after being filtered, dried at 100 °C for 5h in a oven. MAO was prepared by calcining MAH for 4h in a muffle furnace, and calcination temperature was determined to be 500 °C by a differential scanning calorimeter (DSC). Crystal structure and parameters of MAH and MAO were characterized by X/ray diffraction (XRD), good crystal structure was observed and typical peaks of MAH were detected when 2θ was at 11.5 (003), 23.0 (006), 35.0 (009), and 61.0 (110), respectively. The morphology of calcined precursor, i.e. MAO, was investigated with scanning electron microscopy (SEM);the finer lamellar structure and smaller average size of 3μm was observed. Molding research was performed and confirmed by SEM, the results indicated that the surface bulge and cavity with size of several micrometers were increased, which simultaneously suggested the increasing of specific surface area. The catalytic activity of molding MAO was finally examined by using octanol as starting reagent and ethylene oxide as reactant, and narrower molecular distribution was observed comparing with the traditional catalyst-KOH.
文摘We report in situ doping of brushite on zinc manganese oxide（ZMO）, fabricated by calcining a Mn（II） oxalate‐impregnated metal‐organic framework. The doping process was conducted in com‐bination with the photocatalytic water oxidation reaction which was catalyzed by ZMO in neutral phosphate‐buffered aqueous solution containing [Ru（bpy）3]^2＋‐Na2S2O8 and calcium（II） triflate salt, exhibiting greatly enhanced water oxidation performance with optimized turnover frequency of 0.18 mmol（O2） mol（Mn）^（–1） s^（–1）. Different analytical techniques indicated that photodeposited calci‐um‐phosphate（CaP） acted as a co‐catalyst to promote the O2 evolution activity of ZMO. This system involved the use of manganese oxide and calcium ion, and the operation was conducted under am‐bient temperature and neutral conditions, thus, it efficiently mimicked the oxygen‐evolving complex in photosystem II.
文摘Studies were carried out to determine the activity of complexes of the essential amino acids DL-Lysine and L-Methionine with heavy metals in the oxidation of cyclohexene with tert-butylhydroperoxide in toluene at 80°C. All complexes were prepared through interaction of metal ions and DL-Lysine and L-Methionine at room temperature in aqueous solutions. Only the complexes of Mo and W were obtained from acidic aqueous solution. These complexes were characterized by FT-IR, Moessbauer spectroscopy and EPR analysis. The products of the oxidation reactions were identified by GC/MS analysis. The complexes of Mo and V showed the best activity in the epoxidation reaction of cyclohexene in comparison with other complexes, such as Ni, Mn, Zn, Co, Cu, Cr, Fe and W. Using semi-empirical quantum-chemistry methods, the full energy of the Mo complexes was calculated and their probable structure is presented.
基金supported by the grant of the Basic Research Program of the Korea Science & Engineering Foundation (No R01-2006-000-10284-0)
文摘Ferrate（VI） was employed for the oxidation of cyanide （CN） and simultaneous removal of copper or nickel in the mixed/complexed systems of CN-Cu, CN-Ni, or CN-Cu-Ni. The degradation of CN （1.00 mmol/L） and removal of Cu （0.095 mmol/L） were investigated as a function of Fe（Ⅵ） doses from 0.3-2.00 mmol/L at pH 10.0. It was found that Fe（Ⅵ） could readily oxidize CN and the reduction of Fe（Ⅵ） into Fe（Ⅲ） might serve efficiently for the removal of free copper ions. The increase in Fe（Ⅵ） dose apparently favoured the CN oxidation as well as Cu removal. Moreover, the pH dependence study （pH 10.0-13.0） revealed that the oxidation of CN was almost unaffected in the studied pH range （10.0-13.0）, however, the maximum removal efficiency of Cu was obtained at pH 13.0. Similarly, treatment was carded out for CN-Ni system having the initial Ni concentration of 0.170 mmol/L and CN concentration of 1.00 mmol with Fe（Ⅵ） dose 2.00 mmol at various pH values （10.0-12.0）. Results showed a partial oxidation of CN and partial removal of Ni. It can be observed that Fe（Ⅵ） can partially degrade the CN-Ni complex in this pH range. Further, Fe（Ⅵ） was applied for the treatment of simulated industrial waste/effluent waters treatment containing CN, Cu, and Ni.
基金supported by the National Natural Science Foundation of China (51672210, 51323011, 51236007)~~
文摘Photocatalytic water oxidation based on semiconductors usually suffers from poor charge transfer from the bulk to the interface,which is necessary for oxygen generation.Here,we construct a hybrid artificial photosynthesis system for photocatalytic water oxidation.The system consists of BiVO4as the light harvester,a transitional metal complex(M(dca)2,M=Co,Ni,dca:dicyanamide)as the water oxidation catalyst,and S2O82?as a sacrificial electron acceptor.The system exhibits enhanced oxygen evolution activity when M(dca)2is introduced.The BiVO4/Co(dca)2and Bi‐VO4/Ni(dca)2systems exhibit excellent oxygen evolution rates of508.1and297.7μmol/(h·g)compared to the pure BiVO4which shows a photocatalytic oxygen evolution rate of252.2μmol/(h·g)during6h of photocatalytic reaction.Co(dca)2is found to be more effective than Ni(dca)2as a water oxidation catalyst.The enhanced photocatalytic performance is ascribed to the M(dca)2‐engineered BiVO4/electrolyte interface energetics,and to the M(dca)2‐catalyzed surface water oxidation.These two factors lead to a decrease in the energy barrier for hole transfer from the bulk to the surface of BiVO4,which promotes the water oxidation kinetics.
文摘The cheap raw rice husks and the products of their thermal degradation WRHA （white rice husk ash） and BRHA （black rice husk ash）, after vigorously grounding and mixing, can successfully be used as a catalyst support to replace the existing expensive ones. The aim of the present research is to prepare new metal-immobilized complexes based on rice husks and to study their catalytic activity in the oxidation of cyclohexene with tert-butylhydroperoxide. The corresponding metal complexes were obtained by interaction of RRH （raw rice husks） or thermally treated WRHA in air atmosphere. The complexes were obtained from aqueous solutions of various salts such as FeCl2.4H2O, COCl2.6H2O, VOSO4.5H2O and Na2MoO4.2H2O at room temperature. The rice husks-supported metal complexes were identified by infrared spectroscopy. The structure of the iron-containing polymeric materials was evaluated by Mossbauer spectroscopy. The catalytic activity of the molybdenum-containing complex catalyst in the principal epoxidation reaction was higher than that of the vanadium-containing one, whereas, the opposite order of activities was found for the side reaction of allylic hydroxylation of cyclohexene. Under selected reaction conditions, the yields of the principal reaction products cyclohexene oxide （1,2-epoxycyclohexane） and 2-cyclohexene-1-ol were 36.4% and 22.7%, respectively.
文摘Chloromethylated styrene-divinylbenzene copolymer beads with 8% crosslink were chemically modified by reaction with Ethylenediaminetetraaceticacid leading to the incorporation of nitrogen as ligating site on the surface of the polymer. The polymeric ligand on treatment with a solution of Copper chloride gave the corresponding metal complex. The polymer supported Cu(II) complex was characterized by elemental analyses, IR,GC-MS, scanning electron micrographs (SEM). The oxidation of various alcohols such as benzyl alcohol, 2-butanol, and 2-propanol was investigated using the supported metal complexes in presence of molecular oxygen as the oxidant. The swelling studies were done by using different solvents. Kinetic data indicate that the catalysts could be recycled without significant degradation of polymer matrix.
文摘An “experimental” valence state of metal complexes is sometime different from the “formal” oxidation state, especially in the species having redox active ligands. This difference can be seen in biological system, such as iron(IV)-porphyrin π-cation radical in some heme proteins and copper(II)-phenoxyl radical in galactose oxidase (GO). Although structural characterizations of these species by X-ray diffraction methods have been rare due to their stability, some artificial metal-phenoxyl radical complexes have been synthesized and successfully characterized by X-ray crystal structure. In this review, syntheses and X-ray crystal structures of the one-electron oxidized metal-phenolate complexes, metal- phenoxyl radical, and high-valent metal phenolate species are discussed.
基金supported by the Government Planning Organization(GPO2002K120170-7)TUBITAK GrantsCommission for a research grant(No.TBAG-105T428).
文摘The optimum reaction conditions of the oxidative polycondensation of 2-(thien-2-yl-methylene)aminophenol (2-TMAP) has been accomplished by using air O_2,H_2O_2 and NaOCl oxidants in an aqueous alkaline medium between 20℃and 90℃.The structures of the monomer and oligomer were confirmed by FT-IR,UV-Vis,~1H-NMR and ^(13)C-NMR and elemental analysis.TGA-DTA,size exclusion chromatography(SEC) techniques and solubility tests were applied for characterization.The ~1H-NMR and ^(13)C-NMR data show that the polymeriz...
基金supported by the National Natural Science Foundation of China(Grants 22471056,22301058,and 22371065)the Natural Science Foundation of Hebei Province(Grants B2024205007,B2024205033,and B2022205005)+3 种基金the Science and Technology Project of Hebei Education Department(Grant QN2023049)the China Postdoctoral Science Foundation funded project(No.2021TQ0095)the Science Foundation of Hebei Normal University(L2023B51)the Innovation Capability Improvement Plan Project of Hebei Province(22567604H).
文摘Integrating polyoxometalate and catalytically active metal centers with multiple chemical states provides a promising approach for the design of efficient catalysts for benzyl C-H bond oxidation.Herein,two synergistic crystalline catalysts assembled with the Wells-Dawson-type[P_(2)W_(18)O_(62)]^(6−)cluster and heterovalent Cu complexes were synthesized for benzylic C-H oxidation,with the formulae[Cu_(3)^(Ⅰ)Cu_(3)^(Ⅱ)(μ_(2)-OH)6(H_(2)O)_(1.5)(DTAB)_(3)][H_(3)P_(2)W_(18)O_(62)]·18H_(2)O(1)and[Cu_(2)^(Ⅰ)(DTAB)2]{[Cu_(2)^(Ⅰ)(μ_(3)-Cl)][Cu_(4)^(Ⅰ)(μ_(3)-Cl)](DTAB)_(4)}[P_(2)W18O62]·9H_(2)O(2)(DTAB=1,4-di[4H-1,2,4-triazol-4-yl]-benzene).Compound 1 possesses 2-D copper-ligand cationic layers composed of heterovalent[Cu_(3)^(Ⅰ)Cu_(3)^(Ⅱ)(μ_(2)-OH)_(6)]^(3+)chains,in which the protonated[H_(3)P_(2)W_(18)O_(62)]^(3−)polyanions intercalate between them.Compound 2 has a sandwich-like 2-D lamellar structure consisting of three copper-organic units(binuclear{Cu_(2)^(Ⅰ)},trinuclear{Cu_(3)^(Ⅰ)Cl},and tetranuclear{Cu_(4)^(Ⅰ)Cl}units),in which the[P_(2)W_(18)O_(62)]^(6−)clusters are encapsulated.The heterovalent copper species and[P_(2)W_(18)O_(62)]^(6−)clusters within the two compounds make them dual-site synergistic catalysts and the roles of each component in the selective oxidation of benzyl C-H bonds were explored.Using the oxidation of diphenylmethane(DPM)as a model reaction,the two synergistic catalysts displayed ca.95%and 92%DPM conversion with>98%benzophenone(BP)selectivity within 8 h.Mechanism investigations revealed that both copper sites and polyanionic clusters as active centers corporately promoted the adsorption and activation of the t-BuOOH oxidant in the radical-mediated DPM oxidation reaction via coordination and hydrogen bonding interactions to generate active t-BuO·and·OH radicals,accelerating the oxidation of DPM and the formation of BP.Additionally,this kind of synergistic catalyst showcased excellent substrate compatibility and recoverability,as well as robust structural stability.This work affords a promising approach for designing efficient POM-based crystalline catalysts for benzyl C-H bond oxidation.
基金work was supported by the National Research Foundation of Korea(NRF)grant funded by the Korean government[NRF-2022R1I1A1A01064065(G.G.)NRF-2022R1A3B1077319(M.H.L.)+2 种基金NRF-2021R1A2C1011731(C.Y.L.)NRF-2022R1A2C1011793(Y.-H.L.)]the Sejong Science Fellowship Grants(RS-2023-00214034).
文摘Photodynamic therapy(PDT)holds significant promise as a medical treatment approach in human diseases.Recently,PDT has received attention to harness light-induced reactive oxygen species and,subsequently,modify amyloidogenic peptides implicated in human degenerative diseases.Here we report a series of strategically designed photosensitizers comprised of boron-dipyrromethene(BODIPY)scaffolds conjugated with transition metal ions.Our comprehensive biophysical and biochemical investigations demonstrate the efficacy of the photosensitizers in generating reactive oxygen species(ROS),such as singlet oxygen(^(1)O_(2)),superoxide anion radicals(O_(2)^(·-)),and hydroxyl radicals(·OH),upon photoactivation at a relatively longer wavelength,resulting in the oxidation of amyloid-β(Aβ).Consequently,the induced oxidation brings about significant alterations in the aggregation pathways and morphologies of the peptides.Moreover,Aβspecies produced by treating the metal complex,Ir-BDP,exhibiting the highest ROS generation efficiency and photoactivation,are less toxic than the complex-free Aβspecies.Overall,our findings underscore the therapeutic potential of these newly designed photosensitizers in addressing amyloid-related diseases.
