Rare earth elements(REEs) are associated with phosphorite,which is an important strategic reserve resource.During sorting process of phosphorite,REEs may move with specific host minerals,however,occurrence state and m...Rare earth elements(REEs) are associated with phosphorite,which is an important strategic reserve resource.During sorting process of phosphorite,REEs may move with specific host minerals,however,occurrence state and moving pattern of REEs from rock to products are still unclear,which limits separation and enrichment of REEs from phosphorite.Mappings of scanning electron microscope(SEM) and electron probe X-ray micro-analyzer(EPMA) of REEs are highly consistent with those of calcium and phosphorus,and complementary with that of magnesium,which indicates that fluorapatite(Fap) is the main host mineral of REEs.The results of flotation and leaching experiments further indicate that REEs are enriched along with Fap from phosphorite to products.Occupied sites and occupation number of REEs were obtained by X-ray diffraction(XRD) refinement based on the Rietveld method.La,Ce,Nd,and Y can occupy both Ca1 and Ca2 sites.The ratios of La,Ce,Nd,and Y at Ca2 and Cal sites are 4.20,3.70,3.00,and 1.33,showing a decreasing trend,indicating that La,Ce,and Nd tend to occupy Ca2 sites,while Y tends to occupy Ca1 sites.X-ray absorption fine structure(XAFS) shows that REEs mainly form coordinate structures with oxygen and fluorine,which is a direct evidence that REEs replace calcium(Ⅱ) in phosphorite in an isomorphism form.Coordination structure and polyhedral configuration analysis indicate that substitution degree of La,Ce,Nd,and Y is Y> La> Ce≈Nd from easy to difficult at Cal and Ca2 sites.The research enriches the mineralization theory of REEs-bearing phosphorite and provides certain theoretical guidance for selective enrichment of REEs from phosphorite.展开更多
Single-atom catalysts(SACs)have garnered interest in designing their ligand environments,facilitating the modification of single catalytic sites toward high activity and selectivity.Despite various synthetic approache...Single-atom catalysts(SACs)have garnered interest in designing their ligand environments,facilitating the modification of single catalytic sites toward high activity and selectivity.Despite various synthetic approaches,it remains challenging to achieve a catalytically favorable coordination structure simultaneously with the feasible formation of SACs at low temperatures.Here,a new type of coordination structure for Pt SACs is introduced to offer a highly efficient hydrogen evolution reaction(HER)catalyst,where Pt SACs are readily fabricated by atomically confining PtCl_(2)on chemically driven NO_(2)sites in two-dimensional nitrogen-doped carbon nanosheets at room temperature.The resultant Pt SACs form the NO_(2)-Pt-Cl_(2)coordination structure with an atomic dispersion,as revealed by X-ray spectroscopy and transmission electron microscopy investigations.Moreover,our first-principles density functional theory(DFT)calculations show strong interactions in the coordination by computing the binding energy and charge density difference between PtCl_(2)and NO_(2).Pt SACs,established on the NO_(2)-functionalized carbon support,demonstrate the onset potential of 25 mV,Tafel slope of 40 mV dec^(-1),and high specific activity of 1.35 A mgPt^(-1).Importantly,the Pt SACs also exhibit long-term stability up to 110 h,which is a significant advance in the field of single-atom Pt catalysts.The newly developed coordination structure of Pt SACs features a single Pt active center,providing hydrogen binding ability comparable to that of Pt(111),enhanced long-term durability due to strong metal-support interactions,and the advantage of room-temperature fabrication.展开更多
Proton exchange membrane fuel cells have been identified as a potentially valuable technology for the efficient conversion of hydrogen energy into electrical energy.Nevertheless,one significant constraint on the perfo...Proton exchange membrane fuel cells have been identified as a potentially valuable technology for the efficient conversion of hydrogen energy into electrical energy.Nevertheless,one significant constraint on the performance of fuel cells is the oxygen reduction reaction(ORR).It is meaningful to progress the development of representative ORR electrocatalysts.In recent times,there has been an intensified focus on single-atom catalysts(SACs)due to the advantages of homogeneous distribution and high atom utilization efficiency.In particular,the coordination structure of metal sites plays an important role in the electrochemical performance of SACs.However,the relationship between coordination structures and catalytic performance remains unclear.In this review,we summarized the research progress on SACs in electrocatalytic ORR in recent years.Then the structure-activity relationship in the symmetric and asymmetric coordination structures of SACs was clarified.We further proposed rational design principles for regulating the coordination structure of SACs.Finally,the opportunities and challenges were discussed.展开更多
Photocatalytic decomposition of sugars is a promising way of providing H_(2),CO,and HCOOH as sus-tainable energy vectors.However,the production of C_(1) chemicals requires the cleavage of robust C−C bonds in sugars wi...Photocatalytic decomposition of sugars is a promising way of providing H_(2),CO,and HCOOH as sus-tainable energy vectors.However,the production of C_(1) chemicals requires the cleavage of robust C−C bonds in sugars with concurrent production of H_(2),which remains challenging.Here,the photo-catalytic activity for glucose decomposition to HCOOH,CO(C_(1) chemicals),and H_(2) on Cu/TiO_(2)was enhanced by nitrogen doping.Owing to nitrogen doping,atomically dispersed and stable Cu sites resistant to light irradiation are formed on Cu/TiO_(2).The electronic interaction between Cu and nitrogen ions originates valence band structure and defect levels composed of N 2p orbit,distinct from undoped Cu/TiO_(2).Therefore,the lifetime of charge carriers is prolonged,resulting in the pro-duction of C_(1) chemicals and H_(2) with productivities 1.7 and 2.1 folds that of Cu/TiO_(2).This work pro-vides a strategy to design coordinatively stable Cu ions for photocatalytic biomass conversion.展开更多
Carbon-based materials with single-atom(SA)transition metals coordinated with nitrogen(M-N_(x))have attracted extensive attention due to their superior electrochemical CO_(2)reduction reaction(CO_(2)RR)performance.How...Carbon-based materials with single-atom(SA)transition metals coordinated with nitrogen(M-N_(x))have attracted extensive attention due to their superior electrochemical CO_(2)reduction reaction(CO_(2)RR)performance.However,the uncontrolled recombination of metal atoms during the typical high-temperature synthesis process in M-N_(x)causes deterioration of CO_(2)RR activity.Herein,by using electrospinning,we propose a novel strategy for constructing a highly active and selective SA Fe-modified N-doped porous carbon fiber membrane catalyst(Fe-N-CF).This carbon membrane has an interconnected threedimensional structure and a hierarchical porous structure,which can not only confine Fe to be single atom as active centers,but also provide a diffusion channel for CO_(2)molecules.Relying on its special structure and stable mechanical properties,Fe-N-CF is directly used for CO_(2)RR,which presents an excellent selectivity(CO Faradaic efficiency of 97%)and stability.DFT calculations reveals that the synthesized Fe-N_(4)-C can significantly reduce the energy barrier for intermediate COOH^(*)formation and CO desorption.This work highlights the specific advantages of using electrospinning method to prepare the optimal SA catalysts.展开更多
The Fe-N-C material represents an attractive oxygen reduction reaction electrocatalyst,and the FeN_(4)moiety has been identified as a very competitive catalytic active site.Fine tuning of the coordination structure of...The Fe-N-C material represents an attractive oxygen reduction reaction electrocatalyst,and the FeN_(4)moiety has been identified as a very competitive catalytic active site.Fine tuning of the coordination structure of FeN_(4)has an essential impact on the catalytic performance.Herein,we construct a sulfur-modified Fe-N-C catalyst with controllable local coordination environment,where the Fe is coordinated with four in-plane N and an axial external S.The external S atom affects not only the electron distribution but also the spin state of Fe in the FeN_(4)active site.The appearance of higher valence states and spin states for Fe demonstrates the increase in unpaired electrons.With the above characteristics,the adsorption and desorption of the reactants at FeN_(4)active sites are optimized,thus promoting the oxygen reduction reaction activity.This work explores the key point in electronic configuration and coordination environment tuning of FeN_(4)through S doping and provides new insight into the construction of M-N-C-based oxygen reduction reaction catalysts.展开更多
The development of efficient low-load platinum catalysts for CO oxidation is critical for large-scale industrial applications and environmental protection.In this study,a strategy of N_(2)treatment triggered the self-...The development of efficient low-load platinum catalysts for CO oxidation is critical for large-scale industrial applications and environmental protection.In this study,a strategy of N_(2)treatment triggered the self-reforming into fully exposed Pt cluster catalysts was proposed.By adjusting the coordination environment of Pt species on the defect support through N_(2)treatment,the CO catalytic activity was significantly enhanced,achieving complete CO oxidation at 130℃with a Pt loading of only 0.1 wt.%.The turnover frequency of N_(2)-treated Pt_(FEC)/Ti-D at 160℃was 18.3 times that of untreated Pt_(SA)/Ti-D.Comprehensive characterization results indicated that the N_(2)treatment of the Pt single-atom defect catalyst facilitated the reconfiguration and evolution of the defect structure,leading to the aggregation of Pt single atoms into fully exposed Pt clusters.Notably,these fully exposed Pt clusters exhibited a reduced coordination of Pt–O in the first coordination shell compared to single atoms,which resulted in the formation of Pt–Pt metal coordination.This unique coordination structure enhanced the adsorption and activation of CO and O_(2)on the catalyst,thereby resulting in exceptionally low-temperature CO oxidation activity.This work demonstrates a promising strategy for the design,synthesis,and industrial application of efficient low-platinum load catalysts.展开更多
Multiple coordination modes are present copper coordination environment varies in the CuII-histidine complex in solution and the with pH. In this work, we have investigated the coordination geometry of Cu（His）2 comp...Multiple coordination modes are present copper coordination environment varies in the CuII-histidine complex in solution and the with pH. In this work, we have investigated the coordination geometry of Cu（His）2 complex using X-ray absorption fine structure （XAFS） analysis. Copper K-edge XAFS spectra were acquired on aqueous Cu2＋ samples with his- tidine at different pH values. The coordination environments were further confirmed by chemically modified histidine. Results show that the caboxylate groups coordinate at acidic condition, while amino and imidazole nitrogens get coordinated at higher pH. For the co- ordination geometry of Cu（His）2 in solution at physiological pH, the sixfold coordination is preferentially formed, while the fivefold coordination can co-exist in equilibrium.展开更多
The copper（Ⅱ） complexes of pyridine-3-carboxylic acid （nicotinic acid） and pyridine-2-carboxylic acid （isonicotinic acid） were synthesized, and their structures were characterized by elemental analysis, infrare...The copper（Ⅱ） complexes of pyridine-3-carboxylic acid （nicotinic acid） and pyridine-2-carboxylic acid （isonicotinic acid） were synthesized, and their structures were characterized by elemental analysis, infrared spectrum, powder X-ray diffraction and so on. The results show that under experimental conditions, the ligands of synthesized copper nicotinate and copper isonicotinate are coordinated simultaneity with copper（Ⅱ） via the nitrogen of pyridine group and an oxygen of carboxylic acid group to form bidentate chelates. The crystal of copper nicotinate with two six-membered chelate rings belongs to monoclinic system, while that of copper isonicotinate having two five-membered chelate rings is of triclinic system. The tests show that the biological activities, such as the improvement of feed utilization, growth, anti-oxidation ability of organism and disease-resistant power, are different when copper nicotinate, copper inicotinate, copper-lysine chelate, copper-methionine chelate and copper sulphate are added in pig＇s feed, respectively. Due to its higher biological activity, less pollution and lower toxicity, copper nicotinate has wide potential applications as a feed additive.展开更多
In this work, we synthesized a new two-dimensional Cd（Ⅱ） coordination polymer, [Cd（1,4-NDC）（L）]（1）, by using mixed 1,4-naphthalenedicarboxylic acid（1,4-H2NDC） and typical chelating N-donor ligands 2-（2-chl...In this work, we synthesized a new two-dimensional Cd（Ⅱ） coordination polymer, [Cd（1,4-NDC）（L）]（1）, by using mixed 1,4-naphthalenedicarboxylic acid（1,4-H2NDC） and typical chelating N-donor ligands 2-（2-chloro-6-fluorophenyl）-1H-imidazo[4,5-f][1,10]phenanthroline ligand（L）. Compound 1 crystallizes in monoclinic, space group P21/n with a = 12.936（5）, b = 15.245（5）, c = 13.499（5） ？, β = 105.456（5）o, V = 2565.9（16） A^3, Z = 4, C（31）H（16）CdClFN4O4, Mr = 675.33, Dc = 1.748 g/cm^3, F（000） = 1344, μ（MoKa） = 1.011 mm^-1, R = 0.0350 and wR = 0.0926. In 1, each 1,4-NDC anion bridges three adjacent Cd（Ⅱ） atoms to give a two-dimensional layer structure. The L ligands are attached on both sides of the layer in chelating coordination modes. In addition, the N–H···O hydrogen bond between L and 1,4-NDC further stabilizes the layer structure of 1. Moreover, the solid state luminescent property of 1 was also investigated at room temperature.展开更多
A new coordination polymer, [Zn2（m-bix）（p-bdc）2] （1）, was synthesized under hydrothermal conditions by a reaction of 1,3-bis（imidazol-l-ylmethyl）benzene （m-bix）, 1,3-benzene- dicarboxylic acid （H2p-bdc） an...A new coordination polymer, [Zn2（m-bix）（p-bdc）2] （1）, was synthesized under hydrothermal conditions by a reaction of 1,3-bis（imidazol-l-ylmethyl）benzene （m-bix）, 1,3-benzene- dicarboxylic acid （H2p-bdc） and Zn（NO3）2. The colorless block crystals of complex 1 （C30H22N408Zn2） belong to the triclinic system, space group P1 with a = 10.213（2）, b = 12.052（2）, c = 12.392（3） A, a = 82.97（3）, β = 76.04（3）, y = 78.02（3）°, V= 1443.8（5） A3, Z = 2, Dc = 1.604 g/cm3, Mr = 697.26, F（000） = 708, R = 0.0403 and wR = 0.0907 for 4886 observed reflections （1 〉 2σ（I））. In 1, the tetrahedral Zn11 cations are linked by [p-bdc]2- anions into 2D sql networks, which are further connected by bix ligands forming an interesting 2-fold 4,4-connected mog-type 3D network with a point symbol of {4·6^4·8}^2{4^2·6^2·8^2}. Complex 1 was characterized by elemental, IR spectroscopy, powder X-ray diffractions and thermalgravimetric analysis. In addition, complex 1 exhibits coordination induced photoluminescent property.展开更多
Si coordination structures have been proven to greatly influence the ammonia-selective catalytic reduc-tion(NH_(3)-SCR)catalytic properties and the hydrothermal stability of Cu-based silicoaluminophosphate-form cataly...Si coordination structures have been proven to greatly influence the ammonia-selective catalytic reduc-tion(NH_(3)-SCR)catalytic properties and the hydrothermal stability of Cu-based silicoaluminophosphate-form catalysts.However,the role of various Si coordination structures in the NH_(3)-SCR reaction over Cu-SAPO-34 catalyst remains unknown.Herein,a batch of Cu-SAPO-34 samples with various Si contents was synthesized via a one-pot method to study the role of Si coordination structures in the NH_(3)-SCR catalytic properties and hydrothermal stability.Cu/34-2 with the highest proportion of Si(xOAl)(x=1~3)struc-tures exhibits remarkable durability with 90%NO reduction efficiency within 200~450℃ even after a hydrothermal aging treatment at 850℃.In contrast,Cu/34-1 and Cu/34-4 with the highest proportions of Si(4OAl)and Si(0OAl)structures,respectively,are significantly deactivated by the same hydrothermal treatment.To better understand this phenomenon,the relationship between the Si coordination struc-tures and SCR performance is established using characterization techniques and kinetics measurements.Results reveal that a high content of Si(4OAl)and Si(0OAl)is detrimental to the hydrothermal stability of Cu-SAPO-34 catalyst.However,Si(x OAl)(x=1~3)structures are conducive to the stabilization of isolated Cu^(2+),thus enhancing the stability to severe hydrothermal treatment.展开更多
Two 1D coordination polymers [Ln2（dpdc）3（tpy）2·H2O]n [Ln=Nd 1, Yb 2, H2dpdc=2,2＇-biphenyldicarboxylic acid and tpy= 2,2＇：6＇,2＇＇-terpyridine] and one dinuclear complex Er2（dpdc）2（Hdpdc）2（tpy）2 3 we...Two 1D coordination polymers [Ln2（dpdc）3（tpy）2·H2O]n [Ln=Nd 1, Yb 2, H2dpdc=2,2＇-biphenyldicarboxylic acid and tpy= 2,2＇：6＇,2＇＇-terpyridine] and one dinuclear complex Er2（dpdc）2（Hdpdc）2（tpy）2 3 were obtained via hydrothermal reactions and determined by X-ray diffraction analysis. The crystal structure data of 1 and 2 revealed that two coordination polymers were isostructural and possessed a 1D chain framework consisting of eight-coordinated Ln（III） centers. In the asymmetric unit, the two Er（III） ions in 3 were both nine-coordinated and had similar coordination environments. The Er（III） ions were bridged by dpdc2-ligands into dinuclear structures. The complexes were also characterized by IR spectra and thermogravimetric analysis. The solid fluorescence of 1 and 3 was also investigated at room temperature.展开更多
A new Pb（Ⅱ） coordination polymer, [Pb（1,4-chdc）（L）]_n·nH_2O（1）, was synthesized under hydrothermal condition（1,4-H2 chdc = 1,4-cyclohexanedicarboxylic acid and L = 2-（3-fluorophenyl）-1H-imidazo[4,5-f]...A new Pb（Ⅱ） coordination polymer, [Pb（1,4-chdc）（L）]_n·nH_2O（1）, was synthesized under hydrothermal condition（1,4-H2 chdc = 1,4-cyclohexanedicarboxylic acid and L = 2-（3-fluorophenyl）-1H-imidazo[4,5-f][1,10]phenanthroline）. Its crystal structure was determined by singlecrystal X-ray diffraction. Compound 1 crystallizes in triclinic, space group P1 with a = 9.1182（8）, b = 11.3249（10）, c = 12.7326（12） A, α = 77.897（2）, β = 81.644（2）, γ = 84.491（2）°, V = 1269.0（2） A^3, Z = 2, C_（27）H_（24）FN_4O_5Pb, M_r = 710.69, D_c = 1.860 g/cm^3, F（000） = 690, μ（MoKa） = 6.701 mm^（-1）, R = 0.0349 and wR = 0.0746. In 1, each 1,4-chdc anion bridges two neighboring Pb（Ⅱ） atoms in a bidentate chelating coordination mode to give a chain structure. The L ligands are attached on one side of the chain through chelating the Pb（Ⅱ） atoms, and are stacked with those of an adjacent chain through π-π interactions, yielding a layer structure. The O-H···O and N-H···O hydrogen bonding interactions further stabilize the supramolecular layer structure of 1. Moreover, solid state luminescent property of 1 was also studied.展开更多
The reaction of flexible bis（imidazole） ligand and 1,2-bis（imidazol-l＇-yl）methane （bimm） with Co（Ⅱ） salt under ionothermal method resulted in the formation of a new coordination polymer {[Co（bimm）3]·...The reaction of flexible bis（imidazole） ligand and 1,2-bis（imidazol-l＇-yl）methane （bimm） with Co（Ⅱ） salt under ionothermal method resulted in the formation of a new coordination polymer {[Co（bimm）3]·（PF6）2}n （1）. X-ray single-crystal diffraction determination reveals that 1 crystallizes in the triclinic Pi space group, with α = 8.647（6）, b = 12.092（9）, c = 14.967（1 l） A, α = 88.912（8）, β = 81.199（8）, ）, = 89.395（8）°, V= 1546 （2） A3, Z = 2, Mr = 793.39, Dc= 1.704 Mg/m3,μ = 0.768 mm-1 F（000） = 798, the final R = 0.0626 and wR = 0.1634 for 4319 observed reflections with I〉 2σ（I）. In compound 1, the Co（lI） ion is connected to another Co（ll） by two bimm ligands to form 1D double chains which are further linked by bimm ligands to form a 2D wavelike layer. Topologically, the structure of 1 represents a uninodal 2D 4-connected sq1/Shubnikov tetragonal plane net. Moreover, thermogravimetric analyses and photocatalytic property for 1 have also been investigated.展开更多
5-（Hydroxymethyl） isophthalic acid （H2HIA） as a novel organic ligand was prepared from 3,5-bis（methoxycarbonyl）benzoic acid by a two-step method. And then, a 3D helical coor- dination polymer with a 3-fold inter...5-（Hydroxymethyl） isophthalic acid （H2HIA） as a novel organic ligand was prepared from 3,5-bis（methoxycarbonyl）benzoic acid by a two-step method. And then, a 3D helical coor- dination polymer with a 3-fold interpenetration structure, namely [Zn1/2（HIA）1/2（DPEE）1/2]n （1）, was hydrothermally synthesized at 160 ℃, using H2HIA ligands to assemble with DPEE ligands and Zn2＋ ions. Complex 1 crystalizes in orthorhombic system, space group Pnna, with a = 8.2118（5）, b = 17.1698（7）, c =14.9922（7） ？, V = 2113.82（18） ？3, μ = 1.194 mm-1, Z = 4 and S = 0.967. Moreover, some physical characteristics of complex 1, such as powder X-ray diffraction （PXRD）, thermogravimetry analyses （TGA） and photoluminescent properties, were also investigated.展开更多
A one-dimensional chain-like coordination polymer [Mn（phen）（2,4,6-TMBA）2（H2O）]n has been synthesized from 2,4,6-trimethylbenzoic acid, 1,10-phenanthroline and anhydrous manganese（Ⅱ ） sulfate and then characte...A one-dimensional chain-like coordination polymer [Mn（phen）（2,4,6-TMBA）2（H2O）]n has been synthesized from 2,4,6-trimethylbenzoic acid, 1,10-phenanthroline and anhydrous manganese（Ⅱ ） sulfate and then characterized. Crystal data for this complex： tetragonal, space group I41, a = 2.05643（16）, b = 2.05643（16）, c = 1.3939（2） nm, V = 5.8946（11） nm^3, Mr = 579.54, Z = 8, Dc = 1.306 g/cm^3, μ（MoKα） = 0.490 mm^-1, F（000） = 2424, S = 0.985, the final R = 0.0411 and wR = 0.0950. The Flack factor is -0.01（2）. The crystal structure shows that two neighboring man- ganese（Ⅱ ） ions are linked together by one bridge-chelating 2,4,6-trimethylbenzoic group, forming a one-dimensional chain structure. The manganese（Ⅱ ） ion is coordinated with two nitrogen atoms of one 1,10-phenanthroline, three oxygen atoms from three 2,4,6-trimethylbenzoic acids and one water oxygen atom, giving a distorted octahedral coordination geometry. The cyclic voltametric behavior of the complex was also investigated.展开更多
A novel Cd（Ⅱ） coordination polymer with diacylhydrazide ligand N,N？-bis（3-methoxysalicyl）-2,6-pyridinedicarbohydrazide（H_6msphz）,[Cd_2（H_2msphz）（Py）_4]_n（1,Py = pyridine） has been synthesized through sol...A novel Cd（Ⅱ） coordination polymer with diacylhydrazide ligand N,N？-bis（3-methoxysalicyl）-2,6-pyridinedicarbohydrazide（H_6msphz）,[Cd_2（H_2msphz）（Py）_4]_n（1,Py = pyridine） has been synthesized through solvothermal reaction and structurally characterized by single-crystal X-ray diffraction,IR,TGA and PXRD investigations. It crystallizes in triclinic system,space group P1,with a = 11.0230（11）,b = 11.7264（15）,c = 17.3395（14） ？,α = 70.520（9）,β = 84.806（7）,γ = 81.965（9）°,V = 2089.9（4） ？~3,Dc = 1.638 gcm^（–3）,μ = 1.083 mm^（-1）,F（000） = 1032,Z = 2 and S = 1.040. In complex 1,the H_2msphz4-ligand uses not only its coordinated pocket to catch one Cd（Ⅱ） ion,but also its two terminal groups to chelate other two Cd（Ⅱ） ions,leading to the formation of a chain structure. The adjacent chains are further assembled together by two kinds of π-π interactions between the Py rings,resulting in the finial double layered supramolecular structure. In addition,complex 1 is found to show photoluminescence in the solid state at room temperature,which can be ascribed to the intraligand π→π＊ transitions.展开更多
In order to perform a study on the structural modulation in the Cd（Ⅱ）-L architecture（HL =（E）-2-[2-（3-pyridyl）ethenyl]-8-hydroxyquinoline）, two different dicarboxylic acids, namely, 2-aminoterephthalic acid（H...In order to perform a study on the structural modulation in the Cd（Ⅱ）-L architecture（HL =（E）-2-[2-（3-pyridyl）ethenyl]-8-hydroxyquinoline）, two different dicarboxylic acids, namely, 2-aminoterephthalic acid（H_2ATA） and 4,4￠-biphenyldicarboxylic acid（H_2BPDC）, are employed as the secondary auxiliary ligands. Two new complexes [Cd_2L_2（ATA）]（1） and [Cd_2L_2（BPDC）·2MeO H· 4H_2O]（2） with distinct 3D frameworks were obtained. In complex 1, ligands ATA bridge the 1D Cd（Ⅱ）-L infinite chains into a 3D polymeric coordination network. Complex 2 is a 3D porous framework, in which adjacent 2D Cd（Ⅱ）-L coordination layers were linked together by the coor- dinated BPDC ligands. The variant structures of two complexes indicate that the skeleton of dicarboxylate anions plays a great role in the assembly of such different frameworks. In addition, the photoluminescent properties（fluorescent emission, lifetime, and quantum yield） of polymers 1 and 2 were also investigated in the solid state.展开更多
Two cobalt coordination polymers with the same 2D structure have been hydrothermally synthesized based on two bifunctional ligands with tetrazole and phosphonate（phosphonic acid） groups,namely,diethyl 4-（2H-1,2,3,4...Two cobalt coordination polymers with the same 2D structure have been hydrothermally synthesized based on two bifunctional ligands with tetrazole and phosphonate（phosphonic acid） groups,namely,diethyl 4-（2H-1,2,3,4-tetrazol-5-yl） benzylphosphonate（C_2H_5-L1） and 4-（2H-1,2,3,4-tetrazol-5-yl）benzylphosphonic acid（H_2L2）. The structures of the two complexes are characterized by elemental analysis,IR,TGA and X-ray single-crystal/powder diffraction. The pink block crystals of complex [Co（L1）（H_2O）]·H_2O（1） belong to the monoclinic system,space group C2/m with a = 20.8390（11）,b = 7.2695（3）,c = 10.0156（6） A,β = 109.773（7）°,V = 1427.80（13） A^3,Z = 4,D_c = 1.680 mg/cm^-3,M_r = 361.16,F（000） = 740,R = 0.0316 and wR = 0.0826 for 1702 observed reflections（I 〉 2σ（I））. The purple block crystals of complex [Co（L2）（H_2O）]·2H_2O（2） also belong to the monoclinic system,space group C2/c with a = 25.5382（16）,b = 7.3844（3）,c = 15.1925（11） A,β = 124.238（9）°,V = 2368.6（2） A^3,Z = 8,D_c = 1.969 mg/cm^-3,M_r = 351.12,F（000） = 1432,R = 0.0475,wR = 0.1617 for 2088 observed reflections（I 〉 2σ（I））. Both the nitrogen atoms of tetrazole group and oxygen atoms of phosphonate（phosphonic acid） groups in the ligands coordinated with the metal cobalt. The magnetic property of complex 1 is also investigated.展开更多
基金Project supported by Guizhou Provincial Basic Research Program (Natural Science)(Qian Ke He Basic-ZK 2024 General 626)National Natural Science Foundation of China (52164018)Scientific Research Foundation for High-level Talents of Anhui University of Science and Technology (13210025)。
文摘Rare earth elements(REEs) are associated with phosphorite,which is an important strategic reserve resource.During sorting process of phosphorite,REEs may move with specific host minerals,however,occurrence state and moving pattern of REEs from rock to products are still unclear,which limits separation and enrichment of REEs from phosphorite.Mappings of scanning electron microscope(SEM) and electron probe X-ray micro-analyzer(EPMA) of REEs are highly consistent with those of calcium and phosphorus,and complementary with that of magnesium,which indicates that fluorapatite(Fap) is the main host mineral of REEs.The results of flotation and leaching experiments further indicate that REEs are enriched along with Fap from phosphorite to products.Occupied sites and occupation number of REEs were obtained by X-ray diffraction(XRD) refinement based on the Rietveld method.La,Ce,Nd,and Y can occupy both Ca1 and Ca2 sites.The ratios of La,Ce,Nd,and Y at Ca2 and Cal sites are 4.20,3.70,3.00,and 1.33,showing a decreasing trend,indicating that La,Ce,and Nd tend to occupy Ca2 sites,while Y tends to occupy Ca1 sites.X-ray absorption fine structure(XAFS) shows that REEs mainly form coordinate structures with oxygen and fluorine,which is a direct evidence that REEs replace calcium(Ⅱ) in phosphorite in an isomorphism form.Coordination structure and polyhedral configuration analysis indicate that substitution degree of La,Ce,Nd,and Y is Y> La> Ce≈Nd from easy to difficult at Cal and Ca2 sites.The research enriches the mineralization theory of REEs-bearing phosphorite and provides certain theoretical guidance for selective enrichment of REEs from phosphorite.
基金supported by the National Research Foundation of Korea(NRF)(NRF-2020M3H4A3106354,NRF-2021M3I3A1083946,and NRF-2021R1A6A3A01087461)the Korea Institute of Science and Technology,and the KISTI Supercomputing Center(KSC-2023-CRE-0492).
文摘Single-atom catalysts(SACs)have garnered interest in designing their ligand environments,facilitating the modification of single catalytic sites toward high activity and selectivity.Despite various synthetic approaches,it remains challenging to achieve a catalytically favorable coordination structure simultaneously with the feasible formation of SACs at low temperatures.Here,a new type of coordination structure for Pt SACs is introduced to offer a highly efficient hydrogen evolution reaction(HER)catalyst,where Pt SACs are readily fabricated by atomically confining PtCl_(2)on chemically driven NO_(2)sites in two-dimensional nitrogen-doped carbon nanosheets at room temperature.The resultant Pt SACs form the NO_(2)-Pt-Cl_(2)coordination structure with an atomic dispersion,as revealed by X-ray spectroscopy and transmission electron microscopy investigations.Moreover,our first-principles density functional theory(DFT)calculations show strong interactions in the coordination by computing the binding energy and charge density difference between PtCl_(2)and NO_(2).Pt SACs,established on the NO_(2)-functionalized carbon support,demonstrate the onset potential of 25 mV,Tafel slope of 40 mV dec^(-1),and high specific activity of 1.35 A mgPt^(-1).Importantly,the Pt SACs also exhibit long-term stability up to 110 h,which is a significant advance in the field of single-atom Pt catalysts.The newly developed coordination structure of Pt SACs features a single Pt active center,providing hydrogen binding ability comparable to that of Pt(111),enhanced long-term durability due to strong metal-support interactions,and the advantage of room-temperature fabrication.
基金supported the National Natural Science Foundation of China(Nos.22108306 and 22478432)Taishan Scholars Program of Shandong Province(No.tsqn201909065)the Natural Science Foundation of Shandong Province(Nos.ZR2024JQ004 and ZR2021YQ15).
文摘Proton exchange membrane fuel cells have been identified as a potentially valuable technology for the efficient conversion of hydrogen energy into electrical energy.Nevertheless,one significant constraint on the performance of fuel cells is the oxygen reduction reaction(ORR).It is meaningful to progress the development of representative ORR electrocatalysts.In recent times,there has been an intensified focus on single-atom catalysts(SACs)due to the advantages of homogeneous distribution and high atom utilization efficiency.In particular,the coordination structure of metal sites plays an important role in the electrochemical performance of SACs.However,the relationship between coordination structures and catalytic performance remains unclear.In this review,we summarized the research progress on SACs in electrocatalytic ORR in recent years.Then the structure-activity relationship in the symmetric and asymmetric coordination structures of SACs was clarified.We further proposed rational design principles for regulating the coordination structure of SACs.Finally,the opportunities and challenges were discussed.
文摘Photocatalytic decomposition of sugars is a promising way of providing H_(2),CO,and HCOOH as sus-tainable energy vectors.However,the production of C_(1) chemicals requires the cleavage of robust C−C bonds in sugars with concurrent production of H_(2),which remains challenging.Here,the photo-catalytic activity for glucose decomposition to HCOOH,CO(C_(1) chemicals),and H_(2) on Cu/TiO_(2)was enhanced by nitrogen doping.Owing to nitrogen doping,atomically dispersed and stable Cu sites resistant to light irradiation are formed on Cu/TiO_(2).The electronic interaction between Cu and nitrogen ions originates valence band structure and defect levels composed of N 2p orbit,distinct from undoped Cu/TiO_(2).Therefore,the lifetime of charge carriers is prolonged,resulting in the pro-duction of C_(1) chemicals and H_(2) with productivities 1.7 and 2.1 folds that of Cu/TiO_(2).This work pro-vides a strategy to design coordinatively stable Cu ions for photocatalytic biomass conversion.
基金financially supported by Construction Fund for the Collaborative Innovation Center of Biological Diagnosis and Treatment Technology and Equipment in Universities in ShandongProvinceCity-School Integration Development Strategic Project of Jinan(No.JNSX2021015)Shandong Province Key Research and Development Program(No.2021ZDSYS18)。
文摘Carbon-based materials with single-atom(SA)transition metals coordinated with nitrogen(M-N_(x))have attracted extensive attention due to their superior electrochemical CO_(2)reduction reaction(CO_(2)RR)performance.However,the uncontrolled recombination of metal atoms during the typical high-temperature synthesis process in M-N_(x)causes deterioration of CO_(2)RR activity.Herein,by using electrospinning,we propose a novel strategy for constructing a highly active and selective SA Fe-modified N-doped porous carbon fiber membrane catalyst(Fe-N-CF).This carbon membrane has an interconnected threedimensional structure and a hierarchical porous structure,which can not only confine Fe to be single atom as active centers,but also provide a diffusion channel for CO_(2)molecules.Relying on its special structure and stable mechanical properties,Fe-N-CF is directly used for CO_(2)RR,which presents an excellent selectivity(CO Faradaic efficiency of 97%)and stability.DFT calculations reveals that the synthesized Fe-N_(4)-C can significantly reduce the energy barrier for intermediate COOH^(*)formation and CO desorption.This work highlights the specific advantages of using electrospinning method to prepare the optimal SA catalysts.
基金supported by the National Key Research and Development Program of China(Grant No.2020YFA0715000)the National Natural Science Foundation of China(Grant No.52127816)+2 种基金supported by the U.S.Department of Energy(DOE),Office of Energy Efficiency and Renewable Energy,Vehicle Technologies Officethe DOE Office of Science by UChicago Argonne LLC under contract no.DE-AC02-06CH11357the Advanced Photon Source(APS),a U.S.Department of Energy(DOE)Office of Science User Facility,operated for the DOE Office of Science by Argonne National Laboratory under Contract No.DE-AC02-06CH11357
文摘The Fe-N-C material represents an attractive oxygen reduction reaction electrocatalyst,and the FeN_(4)moiety has been identified as a very competitive catalytic active site.Fine tuning of the coordination structure of FeN_(4)has an essential impact on the catalytic performance.Herein,we construct a sulfur-modified Fe-N-C catalyst with controllable local coordination environment,where the Fe is coordinated with four in-plane N and an axial external S.The external S atom affects not only the electron distribution but also the spin state of Fe in the FeN_(4)active site.The appearance of higher valence states and spin states for Fe demonstrates the increase in unpaired electrons.With the above characteristics,the adsorption and desorption of the reactants at FeN_(4)active sites are optimized,thus promoting the oxygen reduction reaction activity.This work explores the key point in electronic configuration and coordination environment tuning of FeN_(4)through S doping and provides new insight into the construction of M-N-C-based oxygen reduction reaction catalysts.
基金supported by the National Natural Science Foundation of China(52170118,52322004,52230002)the China Postdoctoral Science Foundation(2024M763296).
文摘The development of efficient low-load platinum catalysts for CO oxidation is critical for large-scale industrial applications and environmental protection.In this study,a strategy of N_(2)treatment triggered the self-reforming into fully exposed Pt cluster catalysts was proposed.By adjusting the coordination environment of Pt species on the defect support through N_(2)treatment,the CO catalytic activity was significantly enhanced,achieving complete CO oxidation at 130℃with a Pt loading of only 0.1 wt.%.The turnover frequency of N_(2)-treated Pt_(FEC)/Ti-D at 160℃was 18.3 times that of untreated Pt_(SA)/Ti-D.Comprehensive characterization results indicated that the N_(2)treatment of the Pt single-atom defect catalyst facilitated the reconfiguration and evolution of the defect structure,leading to the aggregation of Pt single atoms into fully exposed Pt clusters.Notably,these fully exposed Pt clusters exhibited a reduced coordination of Pt–O in the first coordination shell compared to single atoms,which resulted in the formation of Pt–Pt metal coordination.This unique coordination structure enhanced the adsorption and activation of CO and O_(2)on the catalyst,thereby resulting in exceptionally low-temperature CO oxidation activity.This work demonstrates a promising strategy for the design,synthesis,and industrial application of efficient low-platinum load catalysts.
文摘Multiple coordination modes are present copper coordination environment varies in the CuII-histidine complex in solution and the with pH. In this work, we have investigated the coordination geometry of Cu（His）2 complex using X-ray absorption fine structure （XAFS） analysis. Copper K-edge XAFS spectra were acquired on aqueous Cu2＋ samples with his- tidine at different pH values. The coordination environments were further confirmed by chemically modified histidine. Results show that the caboxylate groups coordinate at acidic condition, while amino and imidazole nitrogens get coordinated at higher pH. For the co- ordination geometry of Cu（His）2 in solution at physiological pH, the sixfold coordination is preferentially formed, while the fivefold coordination can co-exist in equilibrium.
基金Supported by the Natural Science Foundation of Fujian Province (B0510012) and the Science and Technology of Science Foundation of Fujian Education Department (JA04189)
文摘The copper（Ⅱ） complexes of pyridine-3-carboxylic acid （nicotinic acid） and pyridine-2-carboxylic acid （isonicotinic acid） were synthesized, and their structures were characterized by elemental analysis, infrared spectrum, powder X-ray diffraction and so on. The results show that under experimental conditions, the ligands of synthesized copper nicotinate and copper isonicotinate are coordinated simultaneity with copper（Ⅱ） via the nitrogen of pyridine group and an oxygen of carboxylic acid group to form bidentate chelates. The crystal of copper nicotinate with two six-membered chelate rings belongs to monoclinic system, while that of copper isonicotinate having two five-membered chelate rings is of triclinic system. The tests show that the biological activities, such as the improvement of feed utilization, growth, anti-oxidation ability of organism and disease-resistant power, are different when copper nicotinate, copper inicotinate, copper-lysine chelate, copper-methionine chelate and copper sulphate are added in pig＇s feed, respectively. Due to its higher biological activity, less pollution and lower toxicity, copper nicotinate has wide potential applications as a feed additive.
基金Supported by Science and Technology Development Projects of Jilin Province(No.20150101007JC)
文摘In this work, we synthesized a new two-dimensional Cd（Ⅱ） coordination polymer, [Cd（1,4-NDC）（L）]（1）, by using mixed 1,4-naphthalenedicarboxylic acid（1,4-H2NDC） and typical chelating N-donor ligands 2-（2-chloro-6-fluorophenyl）-1H-imidazo[4,5-f][1,10]phenanthroline ligand（L）. Compound 1 crystallizes in monoclinic, space group P21/n with a = 12.936（5）, b = 15.245（5）, c = 13.499（5） ？, β = 105.456（5）o, V = 2565.9（16） A^3, Z = 4, C（31）H（16）CdClFN4O4, Mr = 675.33, Dc = 1.748 g/cm^3, F（000） = 1344, μ（MoKa） = 1.011 mm^-1, R = 0.0350 and wR = 0.0926. In 1, each 1,4-NDC anion bridges three adjacent Cd（Ⅱ） atoms to give a two-dimensional layer structure. The L ligands are attached on both sides of the layer in chelating coordination modes. In addition, the N–H···O hydrogen bond between L and 1,4-NDC further stabilizes the layer structure of 1. Moreover, the solid state luminescent property of 1 was also investigated at room temperature.
基金Support by the National Natural Science Foundation of China(21371052)
文摘A new coordination polymer, [Zn2（m-bix）（p-bdc）2] （1）, was synthesized under hydrothermal conditions by a reaction of 1,3-bis（imidazol-l-ylmethyl）benzene （m-bix）, 1,3-benzene- dicarboxylic acid （H2p-bdc） and Zn（NO3）2. The colorless block crystals of complex 1 （C30H22N408Zn2） belong to the triclinic system, space group P1 with a = 10.213（2）, b = 12.052（2）, c = 12.392（3） A, a = 82.97（3）, β = 76.04（3）, y = 78.02（3）°, V= 1443.8（5） A3, Z = 2, Dc = 1.604 g/cm3, Mr = 697.26, F（000） = 708, R = 0.0403 and wR = 0.0907 for 4886 observed reflections （1 〉 2σ（I））. In 1, the tetrahedral Zn11 cations are linked by [p-bdc]2- anions into 2D sql networks, which are further connected by bix ligands forming an interesting 2-fold 4,4-connected mog-type 3D network with a point symbol of {4·6^4·8}^2{4^2·6^2·8^2}. Complex 1 was characterized by elemental, IR spectroscopy, powder X-ray diffractions and thermalgravimetric analysis. In addition, complex 1 exhibits coordination induced photoluminescent property.
基金financial support from the National Natural Science Foundation of China (No.52000084)the China Postdoctoral Science Foundation (No.2019M662630)。
文摘Si coordination structures have been proven to greatly influence the ammonia-selective catalytic reduc-tion(NH_(3)-SCR)catalytic properties and the hydrothermal stability of Cu-based silicoaluminophosphate-form catalysts.However,the role of various Si coordination structures in the NH_(3)-SCR reaction over Cu-SAPO-34 catalyst remains unknown.Herein,a batch of Cu-SAPO-34 samples with various Si contents was synthesized via a one-pot method to study the role of Si coordination structures in the NH_(3)-SCR catalytic properties and hydrothermal stability.Cu/34-2 with the highest proportion of Si(xOAl)(x=1~3)struc-tures exhibits remarkable durability with 90%NO reduction efficiency within 200~450℃ even after a hydrothermal aging treatment at 850℃.In contrast,Cu/34-1 and Cu/34-4 with the highest proportions of Si(4OAl)and Si(0OAl)structures,respectively,are significantly deactivated by the same hydrothermal treatment.To better understand this phenomenon,the relationship between the Si coordination struc-tures and SCR performance is established using characterization techniques and kinetics measurements.Results reveal that a high content of Si(4OAl)and Si(0OAl)is detrimental to the hydrothermal stability of Cu-SAPO-34 catalyst.However,Si(x OAl)(x=1~3)structures are conducive to the stabilization of isolated Cu^(2+),thus enhancing the stability to severe hydrothermal treatment.
基金Project supported by the Nonprofit Technology & Research in Zhejiang (2011C37010)sponsored by the K.C.Wong Magna Fund in Ningbo University, the Ningbo Municipal Natural Science Foundation (2010A610160),the Subject Object (xk1070) and Foundation (20111045) of Ningbo University
文摘Two 1D coordination polymers [Ln2（dpdc）3（tpy）2·H2O]n [Ln=Nd 1, Yb 2, H2dpdc=2,2＇-biphenyldicarboxylic acid and tpy= 2,2＇：6＇,2＇＇-terpyridine] and one dinuclear complex Er2（dpdc）2（Hdpdc）2（tpy）2 3 were obtained via hydrothermal reactions and determined by X-ray diffraction analysis. The crystal structure data of 1 and 2 revealed that two coordination polymers were isostructural and possessed a 1D chain framework consisting of eight-coordinated Ln（III） centers. In the asymmetric unit, the two Er（III） ions in 3 were both nine-coordinated and had similar coordination environments. The Er（III） ions were bridged by dpdc2-ligands into dinuclear structures. The complexes were also characterized by IR spectra and thermogravimetric analysis. The solid fluorescence of 1 and 3 was also investigated at room temperature.
文摘A new Pb（Ⅱ） coordination polymer, [Pb（1,4-chdc）（L）]_n·nH_2O（1）, was synthesized under hydrothermal condition（1,4-H2 chdc = 1,4-cyclohexanedicarboxylic acid and L = 2-（3-fluorophenyl）-1H-imidazo[4,5-f][1,10]phenanthroline）. Its crystal structure was determined by singlecrystal X-ray diffraction. Compound 1 crystallizes in triclinic, space group P1 with a = 9.1182（8）, b = 11.3249（10）, c = 12.7326（12） A, α = 77.897（2）, β = 81.644（2）, γ = 84.491（2）°, V = 1269.0（2） A^3, Z = 2, C_（27）H_（24）FN_4O_5Pb, M_r = 710.69, D_c = 1.860 g/cm^3, F（000） = 690, μ（MoKa） = 6.701 mm^（-1）, R = 0.0349 and wR = 0.0746. In 1, each 1,4-chdc anion bridges two neighboring Pb（Ⅱ） atoms in a bidentate chelating coordination mode to give a chain structure. The L ligands are attached on one side of the chain through chelating the Pb（Ⅱ） atoms, and are stacked with those of an adjacent chain through π-π interactions, yielding a layer structure. The O-H···O and N-H···O hydrogen bonding interactions further stabilize the supramolecular layer structure of 1. Moreover, solid state luminescent property of 1 was also studied.
基金supported by the Natural Science Foundation of Henan Province(132300410326)the Foundation of the Education Department of Henan Province(13A150801 and 14A150040)
文摘The reaction of flexible bis（imidazole） ligand and 1,2-bis（imidazol-l＇-yl）methane （bimm） with Co（Ⅱ） salt under ionothermal method resulted in the formation of a new coordination polymer {[Co（bimm）3]·（PF6）2}n （1）. X-ray single-crystal diffraction determination reveals that 1 crystallizes in the triclinic Pi space group, with α = 8.647（6）, b = 12.092（9）, c = 14.967（1 l） A, α = 88.912（8）, β = 81.199（8）, ）, = 89.395（8）°, V= 1546 （2） A3, Z = 2, Mr = 793.39, Dc= 1.704 Mg/m3,μ = 0.768 mm-1 F（000） = 798, the final R = 0.0626 and wR = 0.1634 for 4319 observed reflections with I〉 2σ（I）. In compound 1, the Co（lI） ion is connected to another Co（ll） by two bimm ligands to form 1D double chains which are further linked by bimm ligands to form a 2D wavelike layer. Topologically, the structure of 1 represents a uninodal 2D 4-connected sq1/Shubnikov tetragonal plane net. Moreover, thermogravimetric analyses and photocatalytic property for 1 have also been investigated.
基金supported by the Natural Science Foundation of Guizhou Province(20122344)125 program of Guizhou Education Department(2012015)the Doctoral Scientific Fund of Zunyi Normal College(2012BSJJ12)
文摘5-（Hydroxymethyl） isophthalic acid （H2HIA） as a novel organic ligand was prepared from 3,5-bis（methoxycarbonyl）benzoic acid by a two-step method. And then, a 3D helical coor- dination polymer with a 3-fold interpenetration structure, namely [Zn1/2（HIA）1/2（DPEE）1/2]n （1）, was hydrothermally synthesized at 160 ℃, using H2HIA ligands to assemble with DPEE ligands and Zn2＋ ions. Complex 1 crystalizes in orthorhombic system, space group Pnna, with a = 8.2118（5）, b = 17.1698（7）, c =14.9922（7） ？, V = 2113.82（18） ？3, μ = 1.194 mm-1, Z = 4 and S = 0.967. Moreover, some physical characteristics of complex 1, such as powder X-ray diffraction （PXRD）, thermogravimetry analyses （TGA） and photoluminescent properties, were also investigated.
基金Supported by the Construct Program of the Key Discipline in Hunan Province and the Foundation of Education Committee of Hunan Province (06C195)
文摘A one-dimensional chain-like coordination polymer [Mn（phen）（2,4,6-TMBA）2（H2O）]n has been synthesized from 2,4,6-trimethylbenzoic acid, 1,10-phenanthroline and anhydrous manganese（Ⅱ ） sulfate and then characterized. Crystal data for this complex： tetragonal, space group I41, a = 2.05643（16）, b = 2.05643（16）, c = 1.3939（2） nm, V = 5.8946（11） nm^3, Mr = 579.54, Z = 8, Dc = 1.306 g/cm^3, μ（MoKα） = 0.490 mm^-1, F（000） = 2424, S = 0.985, the final R = 0.0411 and wR = 0.0950. The Flack factor is -0.01（2）. The crystal structure shows that two neighboring man- ganese（Ⅱ ） ions are linked together by one bridge-chelating 2,4,6-trimethylbenzoic group, forming a one-dimensional chain structure. The manganese（Ⅱ ） ion is coordinated with two nitrogen atoms of one 1,10-phenanthroline, three oxygen atoms from three 2,4,6-trimethylbenzoic acids and one water oxygen atom, giving a distorted octahedral coordination geometry. The cyclic voltametric behavior of the complex was also investigated.
基金Supported by the National Natural Science Foundation of China(Nos.51572050,21271050 and 21261004)the Guangxi Natural Science Foundation(Nos.2015GXNSFDA139007,2014GXNSFBA118055 and 2013GXNSFGA019008)
文摘A novel Cd（Ⅱ） coordination polymer with diacylhydrazide ligand N,N？-bis（3-methoxysalicyl）-2,6-pyridinedicarbohydrazide（H_6msphz）,[Cd_2（H_2msphz）（Py）_4]_n（1,Py = pyridine） has been synthesized through solvothermal reaction and structurally characterized by single-crystal X-ray diffraction,IR,TGA and PXRD investigations. It crystallizes in triclinic system,space group P1,with a = 11.0230（11）,b = 11.7264（15）,c = 17.3395（14） ？,α = 70.520（9）,β = 84.806（7）,γ = 81.965（9）°,V = 2089.9（4） ？~3,Dc = 1.638 gcm^（–3）,μ = 1.083 mm^（-1）,F（000） = 1032,Z = 2 and S = 1.040. In complex 1,the H_2msphz4-ligand uses not only its coordinated pocket to catch one Cd（Ⅱ） ion,but also its two terminal groups to chelate other two Cd（Ⅱ） ions,leading to the formation of a chain structure. The adjacent chains are further assembled together by two kinds of π-π interactions between the Py rings,resulting in the finial double layered supramolecular structure. In addition,complex 1 is found to show photoluminescence in the solid state at room temperature,which can be ascribed to the intraligand π→π＊ transitions.
基金supported by the National Natural Science Foundation of China(No.21201002)the Foundation of State Key Laboratory of Structural Chemistry(20130016)+1 种基金Anhui Provincial Natural Science Foundation(1308085QB22)Training Programs of Innovation and Entrepreneurship for Undergraduates(201410360023 and 201410360157)
文摘In order to perform a study on the structural modulation in the Cd（Ⅱ）-L architecture（HL =（E）-2-[2-（3-pyridyl）ethenyl]-8-hydroxyquinoline）, two different dicarboxylic acids, namely, 2-aminoterephthalic acid（H_2ATA） and 4,4￠-biphenyldicarboxylic acid（H_2BPDC）, are employed as the secondary auxiliary ligands. Two new complexes [Cd_2L_2（ATA）]（1） and [Cd_2L_2（BPDC）·2MeO H· 4H_2O]（2） with distinct 3D frameworks were obtained. In complex 1, ligands ATA bridge the 1D Cd（Ⅱ）-L infinite chains into a 3D polymeric coordination network. Complex 2 is a 3D porous framework, in which adjacent 2D Cd（Ⅱ）-L coordination layers were linked together by the coor- dinated BPDC ligands. The variant structures of two complexes indicate that the skeleton of dicarboxylate anions plays a great role in the assembly of such different frameworks. In addition, the photoluminescent properties（fluorescent emission, lifetime, and quantum yield） of polymers 1 and 2 were also investigated in the solid state.
基金Supported by the National Natural Science Foundation of China(21371052)the Scientific Research Fund of Heilongjiang Provincial Education Department(12531512)
文摘Two cobalt coordination polymers with the same 2D structure have been hydrothermally synthesized based on two bifunctional ligands with tetrazole and phosphonate（phosphonic acid） groups,namely,diethyl 4-（2H-1,2,3,4-tetrazol-5-yl） benzylphosphonate（C_2H_5-L1） and 4-（2H-1,2,3,4-tetrazol-5-yl）benzylphosphonic acid（H_2L2）. The structures of the two complexes are characterized by elemental analysis,IR,TGA and X-ray single-crystal/powder diffraction. The pink block crystals of complex [Co（L1）（H_2O）]·H_2O（1） belong to the monoclinic system,space group C2/m with a = 20.8390（11）,b = 7.2695（3）,c = 10.0156（6） A,β = 109.773（7）°,V = 1427.80（13） A^3,Z = 4,D_c = 1.680 mg/cm^-3,M_r = 361.16,F（000） = 740,R = 0.0316 and wR = 0.0826 for 1702 observed reflections（I 〉 2σ（I））. The purple block crystals of complex [Co（L2）（H_2O）]·2H_2O（2） also belong to the monoclinic system,space group C2/c with a = 25.5382（16）,b = 7.3844（3）,c = 15.1925（11） A,β = 124.238（9）°,V = 2368.6（2） A^3,Z = 8,D_c = 1.969 mg/cm^-3,M_r = 351.12,F（000） = 1432,R = 0.0475,wR = 0.1617 for 2088 observed reflections（I 〉 2σ（I））. Both the nitrogen atoms of tetrazole group and oxygen atoms of phosphonate（phosphonic acid） groups in the ligands coordinated with the metal cobalt. The magnetic property of complex 1 is also investigated.
