Four distinct coordination polymers(CPs)were successfully synthesized by altering solvent types and adjusting ligand concentrations,and their crystal structures were investigated.[Co(L)(FDCA)(H_(2)O)_(2)]·0.5H_(2...Four distinct coordination polymers(CPs)were successfully synthesized by altering solvent types and adjusting ligand concentrations,and their crystal structures were investigated.[Co(L)(FDCA)(H_(2)O)_(2)]·0.5H_(2)O(1)was synthesized as a 2D structure using Coas the metal source,methanol‑water(4∶6,V/V)as the solvent,and specific concentrations of 2,5‑furandicarboxylic acid(H_(2)FDCA)and 1,3,5‑triimidazole benzene(L).Adjusting to pure water and lowering the concentration of L yielded the 1D chain structure of[Co(HL)2(H_(2)O)_(2)](FDCA)_(2)·6H_(2)O(2).Using Cu(Ⅱ)as the metal source,methanol/water(9∶1,V/V)as the solvent,and specific concentrations of L and H2FDCA,the 1D chain structure of[Cu(L)(FDCA)(H_(2)O)]·2H_(2)O(3)was synthesized.Upon increasing the concentrations of L and H2FDCA,and switching the solvent to pure water,the 1D chain structure of[Cu(HL)_(2)(H_(2)O)_(2)](FDCA)_(2)·6H_(2)O(4)was obtained.This shows that changing the solvent and ligand concentrations can affect the structural changes of CPs.In addition,the solid‑state photoluminescence of CPs 1‑4 at room temperature was studied,and their morphological changes were observed via scanning electron microscopy.Density functional theory calculations revealed that the negative charge concentrates on the O and N atoms of the ligand,facilitating ligand‑metal ion coordination.CCDC:2403934,1;2403935,2;2403936,3;2403938,4.展开更多
Six new lanthanide complexes:[Ln(3,4-DEOBA)3(4,4'-DM-2,2'-bipy)]2·2C_(2)H_(5)OH,[Ln=Dy(1),Eu(2),Tb(3),Sm(4),Ho(5),Gd(6);3,4-DEOBA-=3,4-diethoxybenzoate,4,4'-DM-2,2'-bipy=4,4'-dimethyl-2,2'...Six new lanthanide complexes:[Ln(3,4-DEOBA)3(4,4'-DM-2,2'-bipy)]2·2C_(2)H_(5)OH,[Ln=Dy(1),Eu(2),Tb(3),Sm(4),Ho(5),Gd(6);3,4-DEOBA-=3,4-diethoxybenzoate,4,4'-DM-2,2'-bipy=4,4'-dimethyl-2,2'-bipyridine]were successfully synthesized by the volatilization of the solution at room temperature.The crystal structures of six complexes were determined by single-crystal X-ray diffraction technology.The results showed that the complexes all have a binuclear structure,and the structures contain free ethanol molecules.Moreover,the coordination number of the central metal of each structural unit is eight.Adjacent structural units interact with each other through hydrogen bonds and further expand to form 1D chain-like and 2D planar structures.After conducting a systematic study on the luminescence properties of complexes 1-4,their emission and excitation spectra were obtained.Experimental results indicated that the fluorescence lifetimes of complexes 2 and 3 were 0.807 and 0.845 ms,respectively.The emission spectral data of complexes 1-4 were imported into the CIE chromaticity coordinate system,and their corre sponding luminescent regions cover the yellow light,red light,green light,and orange-red light bands,respectively.Within the temperature range of 299.15-1300 K,the thermal decomposition processes of the six complexes were comprehensively analyzed by using TG-DSC/FTIR/MS technology.The hypothesis of the gradual loss of ligand groups during the decomposition process was verified by detecting the escaped gas,3D infrared spectroscopy,and ion fragment information detected by mass spectrometry.The specific decomposition path is as follows:firstly,free ethanol molecules and neutral ligands are removed,and finally,acidic ligands are released;the final product is the corresponding metal oxide.CCDC:2430420,1;2430422,2;2430419,3;2430424,4;2430421,5;2430423,6.展开更多
Lithium manganese silicate(Li-Mn-Si-O)cathodes are key components of lithium-ion batteries,and their physical and mechanical properties are strongly influenced by their underlying crystal structures.In this study,a ra...Lithium manganese silicate(Li-Mn-Si-O)cathodes are key components of lithium-ion batteries,and their physical and mechanical properties are strongly influenced by their underlying crystal structures.In this study,a range of machine learning(ML)algorithms were developed and compared to predict the crystal systems of Li-Mn-Si-O cathode materials using density functional theory(DFT)data obtained from the Materials Project database.The dataset comprised 211 compositions characterized by key descriptors,including formation energy,energy above the hull,bandgap,atomic site number,density,and unit cell volume.These features were utilized to classify the materials into monoclinic(0)and triclinic(1)crystal systems.A comprehensive comparison of various classification algorithms including Decision Tree,Random Forest,XGBoost,Support VectorMachine,k-Nearest Neighbor,Stochastic Gradient Descent,Gaussian Naive Bayes,Gaussian Process,and Artificial Neural Network(ANN)was conducted.Among these,the optimized ANN architecture(6–14-14-14-1)exhibited the highest predictive performance,achieving an accuracy of 95.3%,aMatthews correlation coefficient(MCC)of 0.894,and an F-score of 0.963,demonstrating excellent consistency with DFT-predicted crystal structures.Meanwhile,RandomForest and Gaussian Processmodels also exhibited reliable and consistent predictive capability,indicating their potential as complementary approaches,particularly when data are limited or computational efficiency is required.This comparative framework provides valuable insights into model selection for crystal system classification in complex cathode materials.展开更多
Vacancy defects,as fundamental disruptions in metallic lattices,play an important role in shaping the mechanical and electronic properties of aluminum crystals.However,the influence of vacancy position under coupled t...Vacancy defects,as fundamental disruptions in metallic lattices,play an important role in shaping the mechanical and electronic properties of aluminum crystals.However,the influence of vacancy position under coupled thermomechanical fields remains insufficiently understood.In this study,transmission and scanning electron microscopy were employed to observe dislocation structures and grain boundary heterogeneities in processed aluminum alloys,suggesting stress concentrations and microstructural inhomogeneities associated with vacancy accumulation.To complement these observations,first-principles calculations and molecular dynamics simulations were conducted for seven single-vacancy configurations in face-centered cubic aluminum.The stress response,total energy,density of states(DOS),and differential charge density were examined under varying compressive strain(ε=0–0.1)and temperature(0–600 K).The results indicate that face-centered vacancies tend to reduce mechanical strength and perturb electronic states near the Fermi level,whereas corner and edge vacancies appear to have weaker effects.Elevated temperatures may partially restore electronic uniformity through thermal excitation.Overall,these findings suggest that vacancy position exerts a critical but position-dependent influence on coupled structure-property relationships,offering theoretical insights and preliminary experimental support for defect-engineered aluminum alloy design.展开更多
In current research,Li_(2)O-Al_(2)O_(3)-SiO_(2)glass-ceramics were prepared by conventional meltquenching and subsequent heat treatment method.The effect of Al_(2)O_(3)content on microstructures,thermal properties,cry...In current research,Li_(2)O-Al_(2)O_(3)-SiO_(2)glass-ceramics were prepared by conventional meltquenching and subsequent heat treatment method.The effect of Al_(2)O_(3)content on microstructures,thermal properties,crystallization behaviours and mechanical properties were investigated.FTIR,Raman spectroscopy and nuclear magnetic resonance spectroscopy microstructure analysis showed that the silico-oxygen network was damaged,while the increase of[AlO_(4)]content repaired the glass network,and finally made the glass network have better connectivity,with the decrease of SiO_(2).The thermal analysis confirmed the increasing glass transition and crystallization temperatures from growing Al_(2)O_(3)content.In addition,different crystal phases can be precipitated in the glass matrix,such as LiAlSi_(4)O_(10),Li_(2)Si_(2)O_(5) in glass with low Al_(2)O_(3)content,the combination of Li_xAl_xSi_(1-x)O_(2),LiAlSi_(3)O_(8),Li_(2)SiO_(3)in glass with intermediate Al_(2)O_(3)content,and the combination of LiAlSi_(2)O_(6),SiO_(2)in glass with high Al_(2)O_(3)content.The hardness of as-prepared glass gradually increases with the increase of the Al_(2)O_(3)content.The Vickers hardness of the glass-ceramics is highly dependent on the Al_(2)O_(3)content in the glass and the heat treatment temperatures,reaching a maximum of 10.11 GPa.Scanning electron microscope images show that the crystals change from spherical to massive and finally to sheet.The change of glass structure,crystal phase and morphology is the main reason for the different mechanical properties.展开更多
The removal of trace plutonium(Pu)from uranium products and organic wastes during spent nuclear fuel reprocessing remains a critical challenge,resulting in excessive plutonium content in uranium products and waste org...The removal of trace plutonium(Pu)from uranium products and organic wastes during spent nuclear fuel reprocessing remains a critical challenge,resulting in excessive plutonium content in uranium products and waste organic liquid.Currently,most organic ligands with selective separation functions are lipophilic,while research on water-soluble,highly selective ligands is relatively scarce,and there are also few reports on the single crystal of these ligands coordinating with plutonium.Herein,a hydrophilic multiamide ligand,N,N,N′,N″,N″-hexaethyl-nitrilotriacetamide(NTAamideC2),was synthesized and evaluated for its Pu(Ⅳ)back-extraction efficiency under harsh conditions.Systematic experiments revealed that NTAamideC2 achieved>99%Pu(Ⅳ)back-extraction rate within 15 min across a wide nitric acid concentration range(0-5 M),even with elevated dibutyl phosphate(DBP≤20000 ppm).Remarkably,the separation factor(SFPu/U)reached 767 at 1.5 M HNO_(3),demonstrating exceptional selectivity over uranium(Ⅵ).Spectrophotometric titration and DFT calculations confirmed the formation of 1:1 and 1:2 Pu(Ⅳ)-NTAamideC2 complexes,with log β values of 7.42±0.01 and 13.23±0.02,respectively.Single-crystal X-ray diffraction analysis of{[Pu_(2)(H_(2)O)_(2)(NTAamideC2)_(4)](H_(2)O)_(2)(NO_(3))(ClO_(4))_(7)}revealed a nine-coordinated PuO_(7)N_(2)geometry,where two NTAamideC2 molecules bind via six O and two N atoms.Compared to conventional agents(AHA/HSC),NTAamideC2 exhibited superior acid tolerance and selectivity,aligning with the CHON principle for sustainable nuclear waste management.This work provides a robust strategy for Pu(Ⅳ)removal in uranium purification cycles and advances fundamental insights into Pu coordination chemistry,offering significant potential for industrial nuclear fuel reprocessing.展开更多
The large volume expansion and rapid capacity attenuation of tin-based electrodes are the main factors limiting their commercial application.The reasonable design of electrode material structure is particularly import...The large volume expansion and rapid capacity attenuation of tin-based electrodes are the main factors limiting their commercial application.The reasonable design of electrode material structure is particularly important for improving its electrochemical performance.Herein,phosphorus-modified graphene encapsulated Sn_(6)O_(4)(OH)_(4)nanoparticles composite(P-Sn_(6)O_(4)(OH)_(4)@RGO)with crystalline-amorphous heterostructure has been successfully designed and prepared.The design of crystalline-amorphous structure has largely enhanced the active sites,and the construction of a graphene encapsulation structure has greatly alleviated volume expansion.Notably,P-Sn_(6)O_(4)(OH)_(4)@RGO obtained an excellent high-rate longterm cycling performance for lithium-ion batteries anode,reaching a high specific capacity of 970 m Ah/g at 1.0 A/g after 1450 cycles.This work demonstrates that restructuring the electrode material's structure and phase through phosphorus modification can effectively improve the electrochemical performance of tin-based electrode materials.展开更多
To expand the study on the structures and biological activities of the anthracyclines anticancer drugs and reduce their toxic side effects,the new anthraquinone derivatives,9‑pyridylanthrahydrazone(9‑PAH)and 9,10‑bisp...To expand the study on the structures and biological activities of the anthracyclines anticancer drugs and reduce their toxic side effects,the new anthraquinone derivatives,9‑pyridylanthrahydrazone(9‑PAH)and 9,10‑bispyridylanthrahydrazone(9,10‑PAH)were designed and synthesized.Utilizing 9‑PAH and 9,10‑PAH as promising anticancer ligands,their respective copper complexes,namely[Cu(L1)Cl_(2)]Cl(1)and{[Cu_(4)(μ_(2)‑Cl)_(3)Cl_(4)(9,10‑PAH)_(2)(DMSO)_(2)]Cl_(2)}_(n)(2),were subsequently synthesized,where the new ligand L1 is formed by coupling two 9‑PAH ligands in the coordination reaction.The chemical and crystal structures of 1 and 2 were elucidated by IR,MS,elemental analysis,and single‑crystal X‑ray diffraction.Complex 1 forms a mononuclear structure.L1 coordinates with Cu through its three N atoms,together with two Cl atoms,to form a five‑coordinated square pyramidal geometry.Complex 2 constitutes a polymeric structure,wherein each structural unit centrosymmetrically encompasses two five‑coordinated binuclear copper complexes(Cu1,Cu2)of 9,10‑PAH,with similar square pyramidal geometry.A chlorine atom(Cl_(2)),located at the symmetry center,bridges Cu1 and Cu1A to connect the two binuclear copper structures.Meanwhile,the two five‑coordinated Cu2 atoms symmetrically bridge the adjacent structural units via one coordinated Cl atom,respectively,thus forming a 1D chain‑like polymeric structure.In vitro anticancer activity assessments revealed that 1 and 2 showed significant cytotoxicity even higher than cisplatin.Specifically,the IC_(50)values of 2 against HeLa‑229 and SK‑OV‑3 cancer cell lines were determined to be(5.92±0.32)μmol·L^(-1)and(6.48±0.39)μmol·L^(-1),respectively.2 could also block the proliferation of HeLa‑229 cells in S phase and significantly induce cell apoptosis.In addition,fluorescence quenching competition experiments suggested that 2 might interact with DNA by an intercalative binding mode,offering insights into its underlying anticancer mechanism.CCDC:2388918,1;2388919,2.展开更多
Ferroelastic rare earth tantalates(RETaO_(4))are widely researched as the next-generation thermal barrier coatings(TBCs),and RETaO_(4)powders are hugely significant for synthesizing their coatings.The current research...Ferroelastic rare earth tantalates(RETaO_(4))are widely researched as the next-generation thermal barrier coatings(TBCs),and RETaO_(4)powders are hugely significant for synthesizing their coatings.The current research used chemical co-precipitation within an automated experimental device to synthesize RETaO_(4)(RE=Nd,Sm,Gd,Ho,Er)powders.The device automatically monitored and controlled the solutions'pH,improving the chemical co-precipitation efficiency.The crystal structure and microstructure of the RETaO_(4)powders can be controlled by changing the annealing temperature,and the materials undergo an m'-m phase transition.The m'-RETaO_(4)powders exhibit nano-size grains,while m-RETaO_(4)powders evince micron-size grains,altered by the annealing temperatures.A simultaneous thermal analysis es-timates the reversive ferroelastic tetragonal-monoclinic phase transition temperatures.Overall,this research focuses on the synthesis,crystal structures,microstructures,and phase transition of the fabricated RETaO_(4)powders.展开更多
Two Gd_(2)complexes,namely[Gd_(2)(dbm)_(2)(HL_(1))_(2)(CH_(3)OH)_(2)]·4CH_(3)OH(1)and[Gd_(2)(dbm)_(2)(L_(2))_(2)(CH_(3)OH)_(2)]·2CH_(3)OH(2),where H_(3)L_(1)=(Z)-N'-[4-(diethylamino)-2-hydroxybenzylidene...Two Gd_(2)complexes,namely[Gd_(2)(dbm)_(2)(HL_(1))_(2)(CH_(3)OH)_(2)]·4CH_(3)OH(1)and[Gd_(2)(dbm)_(2)(L_(2))_(2)(CH_(3)OH)_(2)]·2CH_(3)OH(2),where H_(3)L_(1)=(Z)-N'-[4-(diethylamino)-2-hydroxybenzylidene]-2-hydroxyacetohydrazide,H_(2)L_(2)=(E)-N'-(5-bromo-2-hydroxy-3-methoxybenzylidene)nicotinohydrazide,Hdbm=dibenzoylmethane,have been constructed by adopting the solvothermal method.Structural characterization unveils that both complexes 1 and 2 are constituted by two Gd^(3+)ions,two dbm-ions,two CH_(3)OH molecules,and two polydentate Schiff-base ligands(HL_(1)^(2-)or L_(2)^(2-)).In addition,complex 1 contains four free methanol molecules,whereas complex 2 harbors two free methanol molecules.By investigating the interactions between complexes 1 and 2 and four types of bacteria(Bacillus subtilis,Escherichia coli,Staphylococcus aureus,Candida albicans),it was found that both complexes 1 and 2 exhibited potent antibacte-rial activities.The interaction mechanisms between the ligands H_(3)L_(1),H_(2)L_(2),complexes 1 and 2,and calf thymus DNA(CT-DNA)were studied using ultraviolet-visible spectroscopy,fluorescence titration,and cyclic voltammetry.The results demonstrated that both complexes 1 and 2 can intercalate into CT-DNA molecules,thereby inhibiting bacterial proliferation to achieve the antibacterial effects.CCDC:2401116,1;2401117,2.展开更多
A trinuclear copper complex [Cu_(3)(L2)_(2)(SO_(4))_(2)(H_(2)O)_(7)]·8H_(2)O(1)(HL2=1-hydroxy-3-(pyrazin-2-yl)-N-(pyrazin-2-ylmethyl)imidazo[1,5-a]pyrazine-8-carboxamide) with a multi-substituted imidazo[1,5-a]py...A trinuclear copper complex [Cu_(3)(L2)_(2)(SO_(4))_(2)(H_(2)O)_(7)]·8H_(2)O(1)(HL2=1-hydroxy-3-(pyrazin-2-yl)-N-(pyrazin-2-ylmethyl)imidazo[1,5-a]pyrazine-8-carboxamide) with a multi-substituted imidazo[1,5-a]pyrazine scaffold was serendipitously prepared from the reaction of the pro-ligand of H_(2)L1(N,N'-bis(pyrazin-2-ylmethyl)pyrazine-2,3-dicarboxamide) with CuSO_(4)·5H_(2O) in aqueous solution at room temperature.Complex 1 was characterized by IR,single-crystal X-ray analysis,and magnetic susceptibility measurements.Single-crystal X-ray analysis reveals that the complex consists of three Cu(Ⅱ) ions,two in situ transformed L2~-ligands,two coordinated sulfates,seven coordinated water molecules,and eight uncoordinated water molecules.Magnetic susceptibility measurement indicates that there are obvious ferromagnetic coupling interactions between the adjacent Cu(Ⅱ) ions in 1.CCDC:1852713.展开更多
The reaction of Mg^(2+)and 5-{1,3-dioxo-1H-benzo[de]isoquinolin-2(3H)-yl}terephthalic acid(H_(2)L)leads to two metal-organic frameworks,[Mg(L)(DMF)_(2)(H_(2)O)_(2)]_(2)·5DMF·2H_(2)O(1)with a 1D structure and...The reaction of Mg^(2+)and 5-{1,3-dioxo-1H-benzo[de]isoquinolin-2(3H)-yl}terephthalic acid(H_(2)L)leads to two metal-organic frameworks,[Mg(L)(DMF)_(2)(H_(2)O)_(2)]_(2)·5DMF·2H_(2)O(1)with a 1D structure and[Mg_(2)(L)_(2)(DMSO)_(3)(H_(2)O)](2)with a 2D(4,4)-net structure.Interestingly,the two compounds exhibit distinct luminescent responses to external mechanical stimuli.1 exhibited exceptional resistance mechanical chromic luminescence(RMCL),which can be attributed to the predominant hydrogen bonds and the presence of high-boiling-point solvent molecules within its structure.2 had a reversible MCL property,which can be attributed to the dominantπ-πweak interactions,coupled with the reversible destruction/restoration of its crystallinity under grinding/fumigation.CCDC:2410963,1;2410964,2.展开更多
Two novel lanthanide complexes,[Sm_(2)(BA)_(6)(4-OH-terpy)_(2)]·2H_(2)O·2EtOH(1)and[Pr_(2)(BA)_(6)(4-OH-terpy)_(2)(H_(2)O)_(2)]·HBA·H_(2)O(2),where HBA=benzoic acid,4-OH-terpy=4-hydroxy-2,2'∶6...Two novel lanthanide complexes,[Sm_(2)(BA)_(6)(4-OH-terpy)_(2)]·2H_(2)O·2EtOH(1)and[Pr_(2)(BA)_(6)(4-OH-terpy)_(2)(H_(2)O)_(2)]·HBA·H_(2)O(2),where HBA=benzoic acid,4-OH-terpy=4-hydroxy-2,2'∶6',2″-terpyridine,were successfully synthesized using ultrasonic dissolution and the conventional solution method with two mixed ligands HBA and 4-OH-terpy.During the synthesis,4-OH-terpy was involved in the reaction as a neutral ligand,while HBA,in its deprotonated form(BA-),coordinated with the lanthanide ions as an acidic ligand.The crystal structures of these two complexes were precisely determined by single-crystal X-ray diffraction.Elemental analysis,infrared and Raman spectroscopy,and powder X-ray diffraction techniques were also employed to further explore the physicochemical properties of the two complexes.The single-crystal X-ray diffraction data indicate that,despite their structural differences,both complexes belong to the triclinic crystal system P1 space group.The central lanthanide ions have the same coordination number but exhibit different coordination environments.To comprehensively evaluate the thermal stability of these two complexes,comprehensive tests including thermogravimetric analysis,differential thermogravimetric analysis,differential scanning calorimetry,Fourier transform infrared spectroscopy,and mass spectrometry were conducted.Meanwhile,an in-depth investigation was conducted into the 3D infrared stacked images and mass spectra of the gases emitted from the complexes.In addition,studies of the fluorescence properties of complex1 showed that it exhibited fluorescence emission matching the Sm^(3+)characteristic transition.展开更多
Two new transition-metal coordination polymers,{[Cd(oba)(L)_(2)]·H_(2)O}_n(1)and[Cd(4-nph)(L)_(2)]_n(2)(H_(2)oba=4,4'-oxydibenzoic acid,4-H_(2)nph=4-nitrophthalic acid,L=2,2'-biimidazole),were successfull...Two new transition-metal coordination polymers,{[Cd(oba)(L)_(2)]·H_(2)O}_n(1)and[Cd(4-nph)(L)_(2)]_n(2)(H_(2)oba=4,4'-oxydibenzoic acid,4-H_(2)nph=4-nitrophthalic acid,L=2,2'-biimidazole),were successfully synthesized under hydrothermal conditions and characterized structurally by IR spectroscopy,elemental analyses,single-crystal X-ray diffraction,powder X-ray diffraction,and thermogravimetric analysis.The results of single-crystal X-ray diffraction show that complex 1 presents a 1D zigzag chain structure and further extends to a 2D network through N—H…O hydrogen bonds andπ-πstacking interactions.Meanwhile,complex 2 has a zero-dimensional structure and also extends to form a 2D network through N—H…O hydrogen bonds andπ-πstacking interactions.In addition,both 1and 2 exhibited luminescent properties in the solid state.Furthermore,quantum chemical calculations were carried out on the"molecular fragments"extracted from the crystal structures of 1 and 2 using the PBE0/LANL2DZ method constructed by the Gaussian 16 program.The calculated values signify a significant covalent interaction between the coordination atoms and the Cd(Ⅱ)ions.CCDC:2332173,1;2332176,2.展开更多
Crystal structure prediction aims to predict stable and easily experimentally synthesized materials,which accelerates the discovery of new materials.It is worth noting that the stability of materials is the basis for ...Crystal structure prediction aims to predict stable and easily experimentally synthesized materials,which accelerates the discovery of new materials.It is worth noting that the stability of materials is the basis for ensuring high performance and reliable application of materials.Among which,the thermodynamic and molecular dynamics stability is especially important.Therefore,this paper proposes a method to predict stable crystal structures using formation energy and Lennard-Jones potential as evaluation indicators.Specifically,we use graph neural network models to predict the formation energy of crystals,and employ empirical formulas to calculate the Lennard-Jones potential.Then,we apply Bayesian optimization algorithms to search for crystal structures with low formation energy and Lennard-Jones potential approaching zero,in order to ensure the thermodynamic stability and dynamics stability of materials.In addition,considering the impact of the bonding situation between atoms in the crystal on the structural stability,this article uses contact map to analyze the atomic bonding situation of each crystal to screen out more stable materials.Finally,the experimental results show that the method we proposed can not only reduce the time for crystal structure prediction,but also ensure the stability of crystal materials.展开更多
The high-pressure phase diagram of the Nb-Ti binary system at 0 K is explored by systematic crystal structure prediction.The results highlight a novel niobium-rich bcc phase,Nb_(7)Ti,which is the only dynamically stab...The high-pressure phase diagram of the Nb-Ti binary system at 0 K is explored by systematic crystal structure prediction.The results highlight a novel niobium-rich bcc phase,Nb_(7)Ti,which is the only dynamically stable ordered Nb-Ti compound under ambient pressure.Extensive first-principles calculations have provided insights into the electronic structure,bonding and superconducting properties of Nb_(7)Ti.The superconducting transition temperature(T_(c))for Nb_(7)Ti at ambient pressure is estimated within the framework of BCS theory to be about 17.5 K,which is significantly higher—nearly double—that of the widely utilized NbTi alloy.Furthermore,the results unveil that the high T_(c) is mainly attributed to the unique ordered lattice along with the strong electron-phonon coupling driven by interatomic interactions at mid-frequency and phonon softening induced by low-frequency Fermi surface nesting.Valuable insights are provided for the subsequent synthesis of application-oriented superconductors at low pressure.展开更多
To improve the ability of diglycolamide extractants for the extraction of Sr(Ⅱ)from high-level waste liquid,N,N,N′,N′-tetracyclohexyldiglycolamide(TCHDGA)was proposed and studied to extract Sr(Ⅱ)from nitrate media...To improve the ability of diglycolamide extractants for the extraction of Sr(Ⅱ)from high-level waste liquid,N,N,N′,N′-tetracyclohexyldiglycolamide(TCHDGA)was proposed and studied to extract Sr(Ⅱ)from nitrate media.TCHDGA was prepared and characterized by 1H nuclear magnetic resonance spectroscopy(NMR),^(13)C NMR,and fourier transform infrared spectroscopy(FT-IR).Various factors affecting extraction were studied systematically.In just 20 s,the extraction rate can reach approximately 98.2%.The extraction capacity of cyclohexyl-substituted extractant TCHDGA is tens of times higher than that with linear or branched chain alkyl.The chemical structure of the complex has been demonstrated to be[Sr3TCHDGA]·(NO_(3))_(2),based on FT-IR,X-ray photoelectron spectroscopy(XPS),and crystal structure analysis.The crystal belongs to the monoclinic system,space group P21,and a strontium ion coordinates with nine oxygen atoms,all of which contribute from TCHDGA.The stripping rate can reach over 99%when using distilled water or 0.50 mol·L^(-1)oxalic acid as stripping agents.展开更多
All-inorganic perovskites based on cesium-lead-bromine(Cs-Pb-Br)have been a prominent research focus in optoelectronics in recent years.The optimisation and tunability of their macroscopic properties exploit the confo...All-inorganic perovskites based on cesium-lead-bromine(Cs-Pb-Br)have been a prominent research focus in optoelectronics in recent years.The optimisation and tunability of their macroscopic properties exploit the conformational flexibility,resulting in various crystal structures.Varying synthesis parameters can yield distinct crystal structures from Cs,Pb,and Br precursors,and manually exploring the relationship between these synthesis parameters and the resulting crystal structure is both labour-intensive and time-consuming.Machine learning(ML)can rapidly uncover insights and drive discoveries in chemical synthesis with the support of data,significantly reducing both the cost and development cycle of materials.Here,we gathered synthesis parameters from published literature(220 synthesis runs)and implemented eight distinct ML models,including eXtreme Gradient Boosting(XGB),Decision Tree(DT),Support Vector Machine(SVM),Random Forest(RF),Naïve Bayes(NB),Logistic Regression(LR),Gradient Boosting(GB),and K-Nearest(KN)to classify and predict Cs-Pb-Br crystal structures from given synthesis parameters.Validation accuracy,precision,F1 score,recall,and average area under the curve(AUC)are employed to evaluate these ML models.The XGB model exhibited the best performance,achieving a validation accuracy of 0.841.The trained XGB model was subsequently utilised to predict the structure from 10 experimental runs using a randomised set of parameters,achieving a testing accuracy of 0.8.The results indicate that the Cs/Pb molar ratio,reaction time,and the concentration of organic compounds(ligands)play crucial roles in synthesising various crystal structures of Cs-Pb-Br.This study demonstrates a significant decrease in effort required for experimental procedures and builds a foundational basis for predicting crystal structures from synthesis parameters.展开更多
As an extreme physical condition,high pressure serves as a potent means to substantially modify the interatomic distances and bonding patterns within condensed matter,thereby enabling the macroscopic manipulation of m...As an extreme physical condition,high pressure serves as a potent means to substantially modify the interatomic distances and bonding patterns within condensed matter,thereby enabling the macroscopic manipulation of material properties.We employed the CALYPSO method to predict the stable structures of RbB_(2)C_(4)across the pressure range from 0 GPa to 100 GPa and investigated its physical properties through first-principles calculations.Specially,we found four novel structures,namely,P6_(3)/mcm-,Amm2-,P1-,and I4/mmm-RbB_(2)C_(4).Under pressure conditions,electronic structure calculations reveal that all of them exhibit metallic characteristics.The calculation results of formation enthalpy show that the P6_(3)/mcm structure can be synthesized within the pressure range of 0–40 GPa.Specially,the Amm2,P1,and I4/mmm structures can be synthesized above 4 GPa,6 GPa,10 GPa,respectively.Moreover,the estimated Vickers hardness value of I4/mmm-RbB_(2)C_(4)compound is 47 GPa,suggesting that it is a superhard material.Interestingly,this study uncovers the continuous transformation of the crystal structure of RbB_(2)C_(4)from a layered configuration to folded and tubular forms,ultimately attaining a stabilized cage-like structure under the pressure span of 0–100 GPa.The application of pressure offers a formidable impetus for the advancement and innovation in condensed matter physics,facilitating the exploration of novel states and functions of matter.展开更多
The magnetic refrigeration(MR)based on the principle of magnetocaloric effect(MCE)in magnetic materials was recognized as an alternative cooling way to our present commercialized vapor compression cycle technology.Evi...The magnetic refrigeration(MR)based on the principle of magnetocaloric effect(MCE)in magnetic materials was recognized as an alternative cooling way to our present commercialized vapor compression cycle technology.Evidently,a vital prerequisite for practical applications is the exploration of candidate materials with prominent magnetocaloric performances.In this paper,the polycrystalline garnet RE_(3)Al_(5)O_(12)(RE=Tb,Dy and Ho)compounds with the cubic structure(space group:Ia3d)were prepared using the Pechini sol-gel method,and their crystal structure,magnetic properties and comprehensive magnetocaloric performances were studied.The analysis of magnetic susceptibility curves in a static magnetic field H=0.1 T reveal that the Dy_(3)Al_(5)O_(12)undergoes antiferromagnetic transition with Néel temperature TN≈2.6 K,whereas the Tb_(3)Al_(5)O_(12)and Ho_(3)Al_(5)O_(12)exhibit no features indicative of the magnetic ordering processes down to 1.8 K.The comprehensive magnetocaloric performances,namely the maximum magnetic entropy change and relative cooling power,are derived indirectly from the isothermal field-dependent magnetization data,which yield 11.72,10.42,7.53 J/(kg·K)and 84.56,69.52,70.35 J/kg for the Tb_(3)Al_(5)O_(12),Dy_(3)Al_(5)O_(12)and Ho_(3)Al_(5)O_(12)under a low field change(ΔH)of 0-2 T,respectively.The superior comprehensive magnetocaloric performances and wide operating temperature range of these compounds under lowΔH make them attractive for cryogenic MR technology.展开更多
文摘Four distinct coordination polymers(CPs)were successfully synthesized by altering solvent types and adjusting ligand concentrations,and their crystal structures were investigated.[Co(L)(FDCA)(H_(2)O)_(2)]·0.5H_(2)O(1)was synthesized as a 2D structure using Coas the metal source,methanol‑water(4∶6,V/V)as the solvent,and specific concentrations of 2,5‑furandicarboxylic acid(H_(2)FDCA)and 1,3,5‑triimidazole benzene(L).Adjusting to pure water and lowering the concentration of L yielded the 1D chain structure of[Co(HL)2(H_(2)O)_(2)](FDCA)_(2)·6H_(2)O(2).Using Cu(Ⅱ)as the metal source,methanol/water(9∶1,V/V)as the solvent,and specific concentrations of L and H2FDCA,the 1D chain structure of[Cu(L)(FDCA)(H_(2)O)]·2H_(2)O(3)was synthesized.Upon increasing the concentrations of L and H2FDCA,and switching the solvent to pure water,the 1D chain structure of[Cu(HL)_(2)(H_(2)O)_(2)](FDCA)_(2)·6H_(2)O(4)was obtained.This shows that changing the solvent and ligand concentrations can affect the structural changes of CPs.In addition,the solid‑state photoluminescence of CPs 1‑4 at room temperature was studied,and their morphological changes were observed via scanning electron microscopy.Density functional theory calculations revealed that the negative charge concentrates on the O and N atoms of the ligand,facilitating ligand‑metal ion coordination.CCDC:2403934,1;2403935,2;2403936,3;2403938,4.
文摘Six new lanthanide complexes:[Ln(3,4-DEOBA)3(4,4'-DM-2,2'-bipy)]2·2C_(2)H_(5)OH,[Ln=Dy(1),Eu(2),Tb(3),Sm(4),Ho(5),Gd(6);3,4-DEOBA-=3,4-diethoxybenzoate,4,4'-DM-2,2'-bipy=4,4'-dimethyl-2,2'-bipyridine]were successfully synthesized by the volatilization of the solution at room temperature.The crystal structures of six complexes were determined by single-crystal X-ray diffraction technology.The results showed that the complexes all have a binuclear structure,and the structures contain free ethanol molecules.Moreover,the coordination number of the central metal of each structural unit is eight.Adjacent structural units interact with each other through hydrogen bonds and further expand to form 1D chain-like and 2D planar structures.After conducting a systematic study on the luminescence properties of complexes 1-4,their emission and excitation spectra were obtained.Experimental results indicated that the fluorescence lifetimes of complexes 2 and 3 were 0.807 and 0.845 ms,respectively.The emission spectral data of complexes 1-4 were imported into the CIE chromaticity coordinate system,and their corre sponding luminescent regions cover the yellow light,red light,green light,and orange-red light bands,respectively.Within the temperature range of 299.15-1300 K,the thermal decomposition processes of the six complexes were comprehensively analyzed by using TG-DSC/FTIR/MS technology.The hypothesis of the gradual loss of ligand groups during the decomposition process was verified by detecting the escaped gas,3D infrared spectroscopy,and ion fragment information detected by mass spectrometry.The specific decomposition path is as follows:firstly,free ethanol molecules and neutral ligands are removed,and finally,acidic ligands are released;the final product is the corresponding metal oxide.CCDC:2430420,1;2430422,2;2430419,3;2430424,4;2430421,5;2430423,6.
基金supported by the Learning&Academic Research Institution for Master’s,PhD students,and Postdocs LAMP Program of the National Research Foundation of Korea(NRF)grant funded by the Ministry of Education(No.RS-2023-00301974)This work was also supported by the Glocal University 30 Project fund of Gyeongsang National University in 2025.
文摘Lithium manganese silicate(Li-Mn-Si-O)cathodes are key components of lithium-ion batteries,and their physical and mechanical properties are strongly influenced by their underlying crystal structures.In this study,a range of machine learning(ML)algorithms were developed and compared to predict the crystal systems of Li-Mn-Si-O cathode materials using density functional theory(DFT)data obtained from the Materials Project database.The dataset comprised 211 compositions characterized by key descriptors,including formation energy,energy above the hull,bandgap,atomic site number,density,and unit cell volume.These features were utilized to classify the materials into monoclinic(0)and triclinic(1)crystal systems.A comprehensive comparison of various classification algorithms including Decision Tree,Random Forest,XGBoost,Support VectorMachine,k-Nearest Neighbor,Stochastic Gradient Descent,Gaussian Naive Bayes,Gaussian Process,and Artificial Neural Network(ANN)was conducted.Among these,the optimized ANN architecture(6–14-14-14-1)exhibited the highest predictive performance,achieving an accuracy of 95.3%,aMatthews correlation coefficient(MCC)of 0.894,and an F-score of 0.963,demonstrating excellent consistency with DFT-predicted crystal structures.Meanwhile,RandomForest and Gaussian Processmodels also exhibited reliable and consistent predictive capability,indicating their potential as complementary approaches,particularly when data are limited or computational efficiency is required.This comparative framework provides valuable insights into model selection for crystal system classification in complex cathode materials.
基金supported by the Research Project on Strengthening the Construction of an Important Ecological Security Barrier in Northern China by Higher Education Institutions in the Inner Mongolia Autonomous Region(STAQZX202313)the Inner Mongolia Autonomous Region Education Science‘14th Five-Year Plan’2024 Annual Research Project(NGJGH2024635).
文摘Vacancy defects,as fundamental disruptions in metallic lattices,play an important role in shaping the mechanical and electronic properties of aluminum crystals.However,the influence of vacancy position under coupled thermomechanical fields remains insufficiently understood.In this study,transmission and scanning electron microscopy were employed to observe dislocation structures and grain boundary heterogeneities in processed aluminum alloys,suggesting stress concentrations and microstructural inhomogeneities associated with vacancy accumulation.To complement these observations,first-principles calculations and molecular dynamics simulations were conducted for seven single-vacancy configurations in face-centered cubic aluminum.The stress response,total energy,density of states(DOS),and differential charge density were examined under varying compressive strain(ε=0–0.1)and temperature(0–600 K).The results indicate that face-centered vacancies tend to reduce mechanical strength and perturb electronic states near the Fermi level,whereas corner and edge vacancies appear to have weaker effects.Elevated temperatures may partially restore electronic uniformity through thermal excitation.Overall,these findings suggest that vacancy position exerts a critical but position-dependent influence on coupled structure-property relationships,offering theoretical insights and preliminary experimental support for defect-engineered aluminum alloy design.
基金Funded by the National Key Research Program(No.2024-1129-954-112)National Natural Science Foundation of China(No.52372033)Guangxi Science and Technology Major Program(No.AA24263054)。
文摘In current research,Li_(2)O-Al_(2)O_(3)-SiO_(2)glass-ceramics were prepared by conventional meltquenching and subsequent heat treatment method.The effect of Al_(2)O_(3)content on microstructures,thermal properties,crystallization behaviours and mechanical properties were investigated.FTIR,Raman spectroscopy and nuclear magnetic resonance spectroscopy microstructure analysis showed that the silico-oxygen network was damaged,while the increase of[AlO_(4)]content repaired the glass network,and finally made the glass network have better connectivity,with the decrease of SiO_(2).The thermal analysis confirmed the increasing glass transition and crystallization temperatures from growing Al_(2)O_(3)content.In addition,different crystal phases can be precipitated in the glass matrix,such as LiAlSi_(4)O_(10),Li_(2)Si_(2)O_(5) in glass with low Al_(2)O_(3)content,the combination of Li_xAl_xSi_(1-x)O_(2),LiAlSi_(3)O_(8),Li_(2)SiO_(3)in glass with intermediate Al_(2)O_(3)content,and the combination of LiAlSi_(2)O_(6),SiO_(2)in glass with high Al_(2)O_(3)content.The hardness of as-prepared glass gradually increases with the increase of the Al_(2)O_(3)content.The Vickers hardness of the glass-ceramics is highly dependent on the Al_(2)O_(3)content in the glass and the heat treatment temperatures,reaching a maximum of 10.11 GPa.Scanning electron microscope images show that the crystals change from spherical to massive and finally to sheet.The change of glass structure,crystal phase and morphology is the main reason for the different mechanical properties.
基金supported by the China Institute of Atomic Energy。
文摘The removal of trace plutonium(Pu)from uranium products and organic wastes during spent nuclear fuel reprocessing remains a critical challenge,resulting in excessive plutonium content in uranium products and waste organic liquid.Currently,most organic ligands with selective separation functions are lipophilic,while research on water-soluble,highly selective ligands is relatively scarce,and there are also few reports on the single crystal of these ligands coordinating with plutonium.Herein,a hydrophilic multiamide ligand,N,N,N′,N″,N″-hexaethyl-nitrilotriacetamide(NTAamideC2),was synthesized and evaluated for its Pu(Ⅳ)back-extraction efficiency under harsh conditions.Systematic experiments revealed that NTAamideC2 achieved>99%Pu(Ⅳ)back-extraction rate within 15 min across a wide nitric acid concentration range(0-5 M),even with elevated dibutyl phosphate(DBP≤20000 ppm).Remarkably,the separation factor(SFPu/U)reached 767 at 1.5 M HNO_(3),demonstrating exceptional selectivity over uranium(Ⅵ).Spectrophotometric titration and DFT calculations confirmed the formation of 1:1 and 1:2 Pu(Ⅳ)-NTAamideC2 complexes,with log β values of 7.42±0.01 and 13.23±0.02,respectively.Single-crystal X-ray diffraction analysis of{[Pu_(2)(H_(2)O)_(2)(NTAamideC2)_(4)](H_(2)O)_(2)(NO_(3))(ClO_(4))_(7)}revealed a nine-coordinated PuO_(7)N_(2)geometry,where two NTAamideC2 molecules bind via six O and two N atoms.Compared to conventional agents(AHA/HSC),NTAamideC2 exhibited superior acid tolerance and selectivity,aligning with the CHON principle for sustainable nuclear waste management.This work provides a robust strategy for Pu(Ⅳ)removal in uranium purification cycles and advances fundamental insights into Pu coordination chemistry,offering significant potential for industrial nuclear fuel reprocessing.
基金supported by the Natural Science Foundation of Shandong Province(Nos.ZR2024QE450,ZR2024QB302 and ZR2024QB004)the Taishan Scholars and Young Experts Program of Shandong Province(No.tsqn202211249)Research Program of Qilu Institute of Technology(Nos.QIT 23TP019,QIT23TP010 and QIT24NN007)。
文摘The large volume expansion and rapid capacity attenuation of tin-based electrodes are the main factors limiting their commercial application.The reasonable design of electrode material structure is particularly important for improving its electrochemical performance.Herein,phosphorus-modified graphene encapsulated Sn_(6)O_(4)(OH)_(4)nanoparticles composite(P-Sn_(6)O_(4)(OH)_(4)@RGO)with crystalline-amorphous heterostructure has been successfully designed and prepared.The design of crystalline-amorphous structure has largely enhanced the active sites,and the construction of a graphene encapsulation structure has greatly alleviated volume expansion.Notably,P-Sn_(6)O_(4)(OH)_(4)@RGO obtained an excellent high-rate longterm cycling performance for lithium-ion batteries anode,reaching a high specific capacity of 970 m Ah/g at 1.0 A/g after 1450 cycles.This work demonstrates that restructuring the electrode material's structure and phase through phosphorus modification can effectively improve the electrochemical performance of tin-based electrode materials.
文摘To expand the study on the structures and biological activities of the anthracyclines anticancer drugs and reduce their toxic side effects,the new anthraquinone derivatives,9‑pyridylanthrahydrazone(9‑PAH)and 9,10‑bispyridylanthrahydrazone(9,10‑PAH)were designed and synthesized.Utilizing 9‑PAH and 9,10‑PAH as promising anticancer ligands,their respective copper complexes,namely[Cu(L1)Cl_(2)]Cl(1)and{[Cu_(4)(μ_(2)‑Cl)_(3)Cl_(4)(9,10‑PAH)_(2)(DMSO)_(2)]Cl_(2)}_(n)(2),were subsequently synthesized,where the new ligand L1 is formed by coupling two 9‑PAH ligands in the coordination reaction.The chemical and crystal structures of 1 and 2 were elucidated by IR,MS,elemental analysis,and single‑crystal X‑ray diffraction.Complex 1 forms a mononuclear structure.L1 coordinates with Cu through its three N atoms,together with two Cl atoms,to form a five‑coordinated square pyramidal geometry.Complex 2 constitutes a polymeric structure,wherein each structural unit centrosymmetrically encompasses two five‑coordinated binuclear copper complexes(Cu1,Cu2)of 9,10‑PAH,with similar square pyramidal geometry.A chlorine atom(Cl_(2)),located at the symmetry center,bridges Cu1 and Cu1A to connect the two binuclear copper structures.Meanwhile,the two five‑coordinated Cu2 atoms symmetrically bridge the adjacent structural units via one coordinated Cl atom,respectively,thus forming a 1D chain‑like polymeric structure.In vitro anticancer activity assessments revealed that 1 and 2 showed significant cytotoxicity even higher than cisplatin.Specifically,the IC_(50)values of 2 against HeLa‑229 and SK‑OV‑3 cancer cell lines were determined to be(5.92±0.32)μmol·L^(-1)and(6.48±0.39)μmol·L^(-1),respectively.2 could also block the proliferation of HeLa‑229 cells in S phase and significantly induce cell apoptosis.In addition,fluorescence quenching competition experiments suggested that 2 might interact with DNA by an intercalative binding mode,offering insights into its underlying anticancer mechanism.CCDC:2388918,1;2388919,2.
基金the Rare and Precious Metals Material Genetic Engineering Project of Yunnan Province(202102AB080019-1)National Key Research and Development Program of China(2022YFB3708600)the National Natural Science Foundation of China(91960103).
文摘Ferroelastic rare earth tantalates(RETaO_(4))are widely researched as the next-generation thermal barrier coatings(TBCs),and RETaO_(4)powders are hugely significant for synthesizing their coatings.The current research used chemical co-precipitation within an automated experimental device to synthesize RETaO_(4)(RE=Nd,Sm,Gd,Ho,Er)powders.The device automatically monitored and controlled the solutions'pH,improving the chemical co-precipitation efficiency.The crystal structure and microstructure of the RETaO_(4)powders can be controlled by changing the annealing temperature,and the materials undergo an m'-m phase transition.The m'-RETaO_(4)powders exhibit nano-size grains,while m-RETaO_(4)powders evince micron-size grains,altered by the annealing temperatures.A simultaneous thermal analysis es-timates the reversive ferroelastic tetragonal-monoclinic phase transition temperatures.Overall,this research focuses on the synthesis,crystal structures,microstructures,and phase transition of the fabricated RETaO_(4)powders.
文摘Two Gd_(2)complexes,namely[Gd_(2)(dbm)_(2)(HL_(1))_(2)(CH_(3)OH)_(2)]·4CH_(3)OH(1)and[Gd_(2)(dbm)_(2)(L_(2))_(2)(CH_(3)OH)_(2)]·2CH_(3)OH(2),where H_(3)L_(1)=(Z)-N'-[4-(diethylamino)-2-hydroxybenzylidene]-2-hydroxyacetohydrazide,H_(2)L_(2)=(E)-N'-(5-bromo-2-hydroxy-3-methoxybenzylidene)nicotinohydrazide,Hdbm=dibenzoylmethane,have been constructed by adopting the solvothermal method.Structural characterization unveils that both complexes 1 and 2 are constituted by two Gd^(3+)ions,two dbm-ions,two CH_(3)OH molecules,and two polydentate Schiff-base ligands(HL_(1)^(2-)or L_(2)^(2-)).In addition,complex 1 contains four free methanol molecules,whereas complex 2 harbors two free methanol molecules.By investigating the interactions between complexes 1 and 2 and four types of bacteria(Bacillus subtilis,Escherichia coli,Staphylococcus aureus,Candida albicans),it was found that both complexes 1 and 2 exhibited potent antibacte-rial activities.The interaction mechanisms between the ligands H_(3)L_(1),H_(2)L_(2),complexes 1 and 2,and calf thymus DNA(CT-DNA)were studied using ultraviolet-visible spectroscopy,fluorescence titration,and cyclic voltammetry.The results demonstrated that both complexes 1 and 2 can intercalate into CT-DNA molecules,thereby inhibiting bacterial proliferation to achieve the antibacterial effects.CCDC:2401116,1;2401117,2.
文摘A trinuclear copper complex [Cu_(3)(L2)_(2)(SO_(4))_(2)(H_(2)O)_(7)]·8H_(2)O(1)(HL2=1-hydroxy-3-(pyrazin-2-yl)-N-(pyrazin-2-ylmethyl)imidazo[1,5-a]pyrazine-8-carboxamide) with a multi-substituted imidazo[1,5-a]pyrazine scaffold was serendipitously prepared from the reaction of the pro-ligand of H_(2)L1(N,N'-bis(pyrazin-2-ylmethyl)pyrazine-2,3-dicarboxamide) with CuSO_(4)·5H_(2O) in aqueous solution at room temperature.Complex 1 was characterized by IR,single-crystal X-ray analysis,and magnetic susceptibility measurements.Single-crystal X-ray analysis reveals that the complex consists of three Cu(Ⅱ) ions,two in situ transformed L2~-ligands,two coordinated sulfates,seven coordinated water molecules,and eight uncoordinated water molecules.Magnetic susceptibility measurement indicates that there are obvious ferromagnetic coupling interactions between the adjacent Cu(Ⅱ) ions in 1.CCDC:1852713.
文摘The reaction of Mg^(2+)and 5-{1,3-dioxo-1H-benzo[de]isoquinolin-2(3H)-yl}terephthalic acid(H_(2)L)leads to two metal-organic frameworks,[Mg(L)(DMF)_(2)(H_(2)O)_(2)]_(2)·5DMF·2H_(2)O(1)with a 1D structure and[Mg_(2)(L)_(2)(DMSO)_(3)(H_(2)O)](2)with a 2D(4,4)-net structure.Interestingly,the two compounds exhibit distinct luminescent responses to external mechanical stimuli.1 exhibited exceptional resistance mechanical chromic luminescence(RMCL),which can be attributed to the predominant hydrogen bonds and the presence of high-boiling-point solvent molecules within its structure.2 had a reversible MCL property,which can be attributed to the dominantπ-πweak interactions,coupled with the reversible destruction/restoration of its crystallinity under grinding/fumigation.CCDC:2410963,1;2410964,2.
文摘Two novel lanthanide complexes,[Sm_(2)(BA)_(6)(4-OH-terpy)_(2)]·2H_(2)O·2EtOH(1)and[Pr_(2)(BA)_(6)(4-OH-terpy)_(2)(H_(2)O)_(2)]·HBA·H_(2)O(2),where HBA=benzoic acid,4-OH-terpy=4-hydroxy-2,2'∶6',2″-terpyridine,were successfully synthesized using ultrasonic dissolution and the conventional solution method with two mixed ligands HBA and 4-OH-terpy.During the synthesis,4-OH-terpy was involved in the reaction as a neutral ligand,while HBA,in its deprotonated form(BA-),coordinated with the lanthanide ions as an acidic ligand.The crystal structures of these two complexes were precisely determined by single-crystal X-ray diffraction.Elemental analysis,infrared and Raman spectroscopy,and powder X-ray diffraction techniques were also employed to further explore the physicochemical properties of the two complexes.The single-crystal X-ray diffraction data indicate that,despite their structural differences,both complexes belong to the triclinic crystal system P1 space group.The central lanthanide ions have the same coordination number but exhibit different coordination environments.To comprehensively evaluate the thermal stability of these two complexes,comprehensive tests including thermogravimetric analysis,differential thermogravimetric analysis,differential scanning calorimetry,Fourier transform infrared spectroscopy,and mass spectrometry were conducted.Meanwhile,an in-depth investigation was conducted into the 3D infrared stacked images and mass spectra of the gases emitted from the complexes.In addition,studies of the fluorescence properties of complex1 showed that it exhibited fluorescence emission matching the Sm^(3+)characteristic transition.
文摘Two new transition-metal coordination polymers,{[Cd(oba)(L)_(2)]·H_(2)O}_n(1)and[Cd(4-nph)(L)_(2)]_n(2)(H_(2)oba=4,4'-oxydibenzoic acid,4-H_(2)nph=4-nitrophthalic acid,L=2,2'-biimidazole),were successfully synthesized under hydrothermal conditions and characterized structurally by IR spectroscopy,elemental analyses,single-crystal X-ray diffraction,powder X-ray diffraction,and thermogravimetric analysis.The results of single-crystal X-ray diffraction show that complex 1 presents a 1D zigzag chain structure and further extends to a 2D network through N—H…O hydrogen bonds andπ-πstacking interactions.Meanwhile,complex 2 has a zero-dimensional structure and also extends to form a 2D network through N—H…O hydrogen bonds andπ-πstacking interactions.In addition,both 1and 2 exhibited luminescent properties in the solid state.Furthermore,quantum chemical calculations were carried out on the"molecular fragments"extracted from the crystal structures of 1 and 2 using the PBE0/LANL2DZ method constructed by the Gaussian 16 program.The calculated values signify a significant covalent interaction between the coordination atoms and the Cd(Ⅱ)ions.CCDC:2332173,1;2332176,2.
基金supported by the Nature Science Foundation of China(Nos.61671362 and 62071366)。
文摘Crystal structure prediction aims to predict stable and easily experimentally synthesized materials,which accelerates the discovery of new materials.It is worth noting that the stability of materials is the basis for ensuring high performance and reliable application of materials.Among which,the thermodynamic and molecular dynamics stability is especially important.Therefore,this paper proposes a method to predict stable crystal structures using formation energy and Lennard-Jones potential as evaluation indicators.Specifically,we use graph neural network models to predict the formation energy of crystals,and employ empirical formulas to calculate the Lennard-Jones potential.Then,we apply Bayesian optimization algorithms to search for crystal structures with low formation energy and Lennard-Jones potential approaching zero,in order to ensure the thermodynamic stability and dynamics stability of materials.In addition,considering the impact of the bonding situation between atoms in the crystal on the structural stability,this article uses contact map to analyze the atomic bonding situation of each crystal to screen out more stable materials.Finally,the experimental results show that the method we proposed can not only reduce the time for crystal structure prediction,but also ensure the stability of crystal materials.
基金supported by the National Natural Science Foundation of China(Grant Nos.12122405,12274169,and 11574109)the Fundamental Research Funds for the Central Universities。
文摘The high-pressure phase diagram of the Nb-Ti binary system at 0 K is explored by systematic crystal structure prediction.The results highlight a novel niobium-rich bcc phase,Nb_(7)Ti,which is the only dynamically stable ordered Nb-Ti compound under ambient pressure.Extensive first-principles calculations have provided insights into the electronic structure,bonding and superconducting properties of Nb_(7)Ti.The superconducting transition temperature(T_(c))for Nb_(7)Ti at ambient pressure is estimated within the framework of BCS theory to be about 17.5 K,which is significantly higher—nearly double—that of the widely utilized NbTi alloy.Furthermore,the results unveil that the high T_(c) is mainly attributed to the unique ordered lattice along with the strong electron-phonon coupling driven by interatomic interactions at mid-frequency and phonon softening induced by low-frequency Fermi surface nesting.Valuable insights are provided for the subsequent synthesis of application-oriented superconductors at low pressure.
基金supported by the Natural Science Foundation of Shandong Province(ZR2022QB067).
文摘To improve the ability of diglycolamide extractants for the extraction of Sr(Ⅱ)from high-level waste liquid,N,N,N′,N′-tetracyclohexyldiglycolamide(TCHDGA)was proposed and studied to extract Sr(Ⅱ)from nitrate media.TCHDGA was prepared and characterized by 1H nuclear magnetic resonance spectroscopy(NMR),^(13)C NMR,and fourier transform infrared spectroscopy(FT-IR).Various factors affecting extraction were studied systematically.In just 20 s,the extraction rate can reach approximately 98.2%.The extraction capacity of cyclohexyl-substituted extractant TCHDGA is tens of times higher than that with linear or branched chain alkyl.The chemical structure of the complex has been demonstrated to be[Sr3TCHDGA]·(NO_(3))_(2),based on FT-IR,X-ray photoelectron spectroscopy(XPS),and crystal structure analysis.The crystal belongs to the monoclinic system,space group P21,and a strontium ion coordinates with nine oxygen atoms,all of which contribute from TCHDGA.The stripping rate can reach over 99%when using distilled water or 0.50 mol·L^(-1)oxalic acid as stripping agents.
基金the Italian Space Agency(Agenzia Spaziale Italiana,ASI)in the framework of the Research Day“Giornate della Ricerca Spaziale”initiative through the contract ASI N.2023-4-U.0.
文摘All-inorganic perovskites based on cesium-lead-bromine(Cs-Pb-Br)have been a prominent research focus in optoelectronics in recent years.The optimisation and tunability of their macroscopic properties exploit the conformational flexibility,resulting in various crystal structures.Varying synthesis parameters can yield distinct crystal structures from Cs,Pb,and Br precursors,and manually exploring the relationship between these synthesis parameters and the resulting crystal structure is both labour-intensive and time-consuming.Machine learning(ML)can rapidly uncover insights and drive discoveries in chemical synthesis with the support of data,significantly reducing both the cost and development cycle of materials.Here,we gathered synthesis parameters from published literature(220 synthesis runs)and implemented eight distinct ML models,including eXtreme Gradient Boosting(XGB),Decision Tree(DT),Support Vector Machine(SVM),Random Forest(RF),Naïve Bayes(NB),Logistic Regression(LR),Gradient Boosting(GB),and K-Nearest(KN)to classify and predict Cs-Pb-Br crystal structures from given synthesis parameters.Validation accuracy,precision,F1 score,recall,and average area under the curve(AUC)are employed to evaluate these ML models.The XGB model exhibited the best performance,achieving a validation accuracy of 0.841.The trained XGB model was subsequently utilised to predict the structure from 10 experimental runs using a randomised set of parameters,achieving a testing accuracy of 0.8.The results indicate that the Cs/Pb molar ratio,reaction time,and the concentration of organic compounds(ligands)play crucial roles in synthesising various crystal structures of Cs-Pb-Br.This study demonstrates a significant decrease in effort required for experimental procedures and builds a foundational basis for predicting crystal structures from synthesis parameters.
基金Project supported by the Jilin Provincial Science and Technology Development Joint Fund Project(Grant No.YDZJ202201ZYTS581)supported by the Scientific and Technological Research Project of Jilin Provincial Education Department(Grant No.JJKH20240077KJ).
文摘As an extreme physical condition,high pressure serves as a potent means to substantially modify the interatomic distances and bonding patterns within condensed matter,thereby enabling the macroscopic manipulation of material properties.We employed the CALYPSO method to predict the stable structures of RbB_(2)C_(4)across the pressure range from 0 GPa to 100 GPa and investigated its physical properties through first-principles calculations.Specially,we found four novel structures,namely,P6_(3)/mcm-,Amm2-,P1-,and I4/mmm-RbB_(2)C_(4).Under pressure conditions,electronic structure calculations reveal that all of them exhibit metallic characteristics.The calculation results of formation enthalpy show that the P6_(3)/mcm structure can be synthesized within the pressure range of 0–40 GPa.Specially,the Amm2,P1,and I4/mmm structures can be synthesized above 4 GPa,6 GPa,10 GPa,respectively.Moreover,the estimated Vickers hardness value of I4/mmm-RbB_(2)C_(4)compound is 47 GPa,suggesting that it is a superhard material.Interestingly,this study uncovers the continuous transformation of the crystal structure of RbB_(2)C_(4)from a layered configuration to folded and tubular forms,ultimately attaining a stabilized cage-like structure under the pressure span of 0–100 GPa.The application of pressure offers a formidable impetus for the advancement and innovation in condensed matter physics,facilitating the exploration of novel states and functions of matter.
基金supported by the National Natural Science Foundation of China(52301240,52472274)the Fundamental Research Funds for the Provincial Universities of Zhejiang(GK259909299001-022)。
文摘The magnetic refrigeration(MR)based on the principle of magnetocaloric effect(MCE)in magnetic materials was recognized as an alternative cooling way to our present commercialized vapor compression cycle technology.Evidently,a vital prerequisite for practical applications is the exploration of candidate materials with prominent magnetocaloric performances.In this paper,the polycrystalline garnet RE_(3)Al_(5)O_(12)(RE=Tb,Dy and Ho)compounds with the cubic structure(space group:Ia3d)were prepared using the Pechini sol-gel method,and their crystal structure,magnetic properties and comprehensive magnetocaloric performances were studied.The analysis of magnetic susceptibility curves in a static magnetic field H=0.1 T reveal that the Dy_(3)Al_(5)O_(12)undergoes antiferromagnetic transition with Néel temperature TN≈2.6 K,whereas the Tb_(3)Al_(5)O_(12)and Ho_(3)Al_(5)O_(12)exhibit no features indicative of the magnetic ordering processes down to 1.8 K.The comprehensive magnetocaloric performances,namely the maximum magnetic entropy change and relative cooling power,are derived indirectly from the isothermal field-dependent magnetization data,which yield 11.72,10.42,7.53 J/(kg·K)and 84.56,69.52,70.35 J/kg for the Tb_(3)Al_(5)O_(12),Dy_(3)Al_(5)O_(12)and Ho_(3)Al_(5)O_(12)under a low field change(ΔH)of 0-2 T,respectively.The superior comprehensive magnetocaloric performances and wide operating temperature range of these compounds under lowΔH make them attractive for cryogenic MR technology.
