The launch of International Thermonuclear Experimental Reactor project paves the way to wide adoption of DT fusion energy as future energy source.Efficient fuel cycle to minimize strategic tritium inventory proves cru...The launch of International Thermonuclear Experimental Reactor project paves the way to wide adoption of DT fusion energy as future energy source.Efficient fuel cycle to minimize strategic tritium inventory proves crucial for commercially viable fusion technologies.ZrCo alloy is considered as a promising candidate for fast isotope handling.However,cycling degradation caused by hydrogen-induced disproportionation results in severe tritium trapping,thus impeding its practical application.Herein,an isostructural transition is successfully constructed with low hysterisis,ameliorated plateau flatness of pressure-composition isotherms and improved high-temperature durability for hydrogen trapping minimization.Specifically,the optimal Zr_(0.7)Hf_(0.15)Nb_(0.15)Co_(0.6)Cu_(0.15)Ni_(0.25) alloy adopts Hf-Nb and Cu-Ni as Zr and Co side doping elements,exhibiting substantial thermodynamic destabilization with nearly 90℃ reduction of delivery temperature,and significant kinetic promotion with a threefold lower energy barrier.More importantly,both hydrogen utilization and cycling retention of optimal alloy are increased by about twenty times compared with pristine alloy after 100 cycles at 500℃.Minimized disproportionation driving force from both isostructural transition and suppressed 8e hydrogen occupation realizes full potential of optimal alloy.This work demonstrates the effectiveness of combining isostructural transformation and high-temperature durability improvement to enhance the hydrogen utilization of ZrCo-based alloys and other hydrogen storage materials.展开更多
The high-pressure structural,vibrational and electrical properties for realgar were investigated by in-situ Raman scattering and electrical conductivity experiments combined with first-principle calculations up to~30....The high-pressure structural,vibrational and electrical properties for realgar were investigated by in-situ Raman scattering and electrical conductivity experiments combined with first-principle calculations up to~30.8 GPa.It was verified that realgar underwent an isostructural phase transition at~6.3 GPa and a metallization at a higher pressure of~23.5 GPa.The isostructural phase transition was well evidenced by the obvious variations of Raman peaks,electrical conductivity,crystal parameters and the As–S bond length.The phase transition of metallization was in closely associated with the closure of bandgap rather than caused by the structural phase transition.And furthermore,the metallic realgar exhibited a relatively low compressibility with the unit cell volume V_(0)=718.1.4Å^(3)and bulk modulus B_(0)=36.1 GPa.展开更多
High pressure structural phase transition of monoclinic paraotwayite type α-Ni(OH)2 nanowires with a diameter of15 nm–20 nm and a length of several micrometers were studied by synchrotron x-ray diffraction(XRD) and ...High pressure structural phase transition of monoclinic paraotwayite type α-Ni(OH)2 nanowires with a diameter of15 nm–20 nm and a length of several micrometers were studied by synchrotron x-ray diffraction(XRD) and Raman spectra.It is found that the α-Ni(OH)2 nanowires experience an isostructural phase transition associated with the amorphization of the H-sublattice of hydroxide in the interlayer spaces of the two-dimensional crystal structure at 6.3 GPa–9.3 GPa. We suggest that the isostructural phase transition can be attributed to the amorphization of the H-sublattice. The bulk moduli for the low pressure phase and the high pressure phase are 41.2(4.2) GPa and 94.4(5.6) GPa, respectively. Both the pressure-induced isostructural phase transition and the amorphization of the H-sublattice in the α-Ni(OH)2 nanowires are reversible upon decompression. Our results show that the foreign anions intercalated between the α-Ni(OH)2 layers play important roles in their structural phase transition.展开更多
Isostructural multicomponent crystals provide a promising way for fine-tuning physicochemical properties, whereas their design remains quite challenging. The purpose of this work was to provide a new strategy for obta...Isostructural multicomponent crystals provide a promising way for fine-tuning physicochemical properties, whereas their design remains quite challenging. The purpose of this work was to provide a new strategy for obtaining isostructural multicomponent crystals by introducing coformers with functional group positional isomerism. Five isostructural salts of an antitumor drug dimethylaminomicheliolide(DMAMCL) were reported and designed with a series of dihydroxybenzoic acid regioisomers for the first time, which were identified by power and single-crystal X-ray diffractions. Similar lattice parameters suggested these obtained salts may have the same crystal packing mode. The quantitative similarity parameters via XPac, Crystal CMP and Mercury program further proved these crystal structures are3D isostructural. Hirshfeld surface maps and 2D fingerprint plots show that the isostructural salts have similar intermolecular interactions. Compared with DMAMCL, obvious improvement was observed in the thermal stability, hygroscopicity, and solubility of these isostructural salts. Meanwhile, isostructural crystals may have different physicochemical properties, even though the shape and molecular size are similar and the packing of crystal structures is equally matched.展开更多
The electrochemical enantiorecognition of amino acids has wide applications,but the creation of the required uniform and homochiral microenvironments at electrodes remains a huge challenge.With highly ordered and adju...The electrochemical enantiorecognition of amino acids has wide applications,but the creation of the required uniform and homochiral microenvironments at electrodes remains a huge challenge.With highly ordered and adjustable structures,homochiral MOFs may provide nice platforms for fine regulation of the microenvironments.Herein,we report for the first time the distinct enantiodiscriminative abilities controlled by metal centers in isostructural homochiral MOFs.Cu-TBLeuBpa,which has a L-leucine-derived linker with Cu_((II))in a severely elongated octahedron,displays highly efficient enantiomeric discrimination of Tyr and Trp,with high current ratios(I_(L)/I_(D),up to 9.83),large potential differences(EL-ED,up to 160 mV),and ultralow detection limits for the L-isomers(2-4 nM).The overall performance is remarkably superior to previous sensors for these amino acids.The Cu-TBLeuBpa sensor has been successfully utilized for the quantitative assay of L-Tyr and L-Trp in racemic mixtures and human urine.We demonstrated that not only the chiral aliphatic amino acid moiety but also the achiral aromatic moiety(phenol or indole)plays a decisive role in the biased adsorption and electrochemical recognition of the L isomers.In contrast,the isostructural Co-TBLeuBpa,in which Co(II)shows a quasi-regular octahedron,is unable to distinguish Tyr enantiomers and shows weakened but still conspicuous performance for Trp enantiomers.This work highlights that a small alteration of the metal geometry in MOFs can have a significant or even decisive impact on enantiorecognition,opening up new perspectives for the design of chiral sensing materials.展开更多
A family of isostructural heterometallic MOFs based on Fe_(2)M clusters(MOF-Fe_(2)M;M=Fe,Co and Ni,respectively)have been synthesized and serve as potential proton conductors and photocatalysts for CO_(2)photoreductio...A family of isostructural heterometallic MOFs based on Fe_(2)M clusters(MOF-Fe_(2)M;M=Fe,Co and Ni,respectively)have been synthesized and serve as potential proton conductors and photocatalysts for CO_(2)photoreduction,exhibiting varied proton conductivities and photocatalytic performances.展开更多
Two isostructural dense lanthanide metal-organic frameworks derived from an extended ligand 1,3,5-tris(4-carboxyphenyl)benzene(H3BTB),[Ln(BTB)H_(2)O]n(Ln=Eu,1;Ln=Dy,2),which are constructed via a cross-like folding as...Two isostructural dense lanthanide metal-organic frameworks derived from an extended ligand 1,3,5-tris(4-carboxyphenyl)benzene(H3BTB),[Ln(BTB)H_(2)O]n(Ln=Eu,1;Ln=Dy,2),which are constructed via a cross-like folding assembly strategy,were yielded by‘two-step warming solvothermal synthesis’.Complex 1 shows luminescence while complex 2 exhibits field-induced two-step magnetic relaxation.展开更多
The design and development of advanced hypergolic metal–organic frameworks(HMOFs)for space exploration have attracted widespread attention in recent years.However,enhancing the energy densities and elucidating the re...The design and development of advanced hypergolic metal–organic frameworks(HMOFs)for space exploration have attracted widespread attention in recent years.However,enhancing the energy densities and elucidating the relationship between the structure and hypergolic properties of HMOFs are still in their infancy.展开更多
The performance of asymmetric supercapacitors(ASCs)is strongly restricted by the capacity gap between the positive and negative electrodes.To address this issue,two new electrode materials deriving from Co‐and Fe‐ba...The performance of asymmetric supercapacitors(ASCs)is strongly restricted by the capacity gap between the positive and negative electrodes.To address this issue,two new electrode materials deriving from Co‐and Fe‐based metal–organic frameworks(MOFs,Co‐TAMBA‐d,and Fe‐TAMBA‐d)through a single‐step sintering method have been developed by considering the superiorities of the derivatives of MOFs including large surface areas,sufficient metal‐atom‐doping content,and extreme surface wettability to the bath solution.The as‐prepared Co‐TAMBA‐d as a positive electrode delivers typical pseudocapacitive behavior with the improvement of capacity,which is better than those of pristine MOF materials,while Fe‐TAMBA‐d as negative electrodes displays better electrochemical behavior than those of activated carbon.ASCs based on these two electrodes exhibits excellent energy density and power density of 47Wh/kg and 1658 W/kg,respectively,where this device can maintain prominent cycling stability with capacity retention after 5000 cycles being about 75%.Furthermore,the capacity can feed a series of red light‐emitting diodes,which gives solid evidence of the potential utilization.These results can afford the feasibility of isostructural MOF derivatives as promising electrodes in novel ASCs.展开更多
The relation between cell-edges or unit-cell volumes of isostructural compounds and theionic radii has wide applications in crystal chemistry. The authors have proved: (1) For a series of multiple isostructural compou...The relation between cell-edges or unit-cell volumes of isostructural compounds and theionic radii has wide applications in crystal chemistry. The authors have proved: (1) For a series of multiple isostructural compounds such as A_mB_n…X_p, when the anionand other cations are fixed, there exists the following relation between the unit-cell volume Vand the radius r_A of a certain cation such as A: V = (a + br_A)(r_X + r_A)~3 (a and b are constants). (2) For binary isostructural compounds A_mX_p, the above relation is reduced to V = k(r_X + r_A)~3 (k is a constant). (3) For binary isostructural compounds the relation between V and r_A^3 is approximatelylinear, and for multiple compounds, it is often curvilinear but still approximately linear whenthe variation of r_A is slight. As another approximation, a linear relation also exists betweenV and r_A for isostructural compounds. (4) The relation of ce1l-edge a vs. r_A is linear for binary isostructural compounds. Butno such a good linear relation exists for multiple isostructural compounds.展开更多
Three new isostructural coordination polymers,namely,[Mg(cpna)(H2O)2]n(1),[Mn(cpna)(H_(2)O)_(2)]n(2)and[Co(cpna)(H_(2)O)_(2)]n(3)(H_(2) cpna=5-(3-carboxylphenyl)nicotic acid)are reported.They were synthesized by hydro...Three new isostructural coordination polymers,namely,[Mg(cpna)(H2O)2]n(1),[Mn(cpna)(H_(2)O)_(2)]n(2)and[Co(cpna)(H_(2)O)_(2)]n(3)(H_(2) cpna=5-(3-carboxylphenyl)nicotic acid)are reported.They were synthesized by hydrothermal reactions of transition metal or alkaline earth metal chloride with 5-(3-carboxylphenyl)nicotic acid,respectively.Complexes 1~3 exhibit 2D layers with a 3,3-connected topology with Schl?fli symbol{4.82}.Such layers including hexagonal rings and a quadrangular ring are further extended into an ordered 3D framework by hydrogen bonds between the cpna2-ligands and water molecules.The rare complex 1 has excellent luminescence and can be used as luminescent materials,while 2 and 3 possess prominent magnetism with potential applications in magnetic materials.展开更多
Separation of ternary C_(4) olefins(n-butene,iso-butene and 1,3-butadiene)is very challenging but crucial in the petrol-chemical industry due to their similar molecular sizes and properties.Herein,to optimize the sepa...Separation of ternary C_(4) olefins(n-butene,iso-butene and 1,3-butadiene)is very challenging but crucial in the petrol-chemical industry due to their similar molecular sizes and properties.Herein,to optimize the separation efficiency for separation of C_(4) olefins,a new Hofmann-type MOF,[Ni(piz)Ni(CN)_(4)](piz=piperazine)-isostructural to the typical one[Ni(pyz)Ni(CN)_(4)](pyz=pyrazine),has been synthesized by a facile method from aqueous solution.The pore size reduction of[Ni(piz)Ni(CN)_(4)](3.62A,in contrast to 3.85A in[Ni(pyz)Ni(CN)_(4)])results in negligible iso-butene(i-C_(4)H_(8))uptake(from 2.92 to 0.04 mmol g^(-1))whereas retaining significant uptake for 1,3-butadiene(1,3-C_(4)H_(6),1.96 mmol g^(-1))and n-butene(n-C_(4)H_(8),1.47 mmol g^(-1)),showing much higher uptake ratios of 1,3-C_(4)H_(6)/i-C_(4)H_(8)(47)and n-C_(4)H_(8)/i-C_(4)H_(8)(35)that outperform most of the benchmark porous materials for separating C_(4) olefins.Breakthrough experiments demonstrate successful separation of high-purity(99.9999%)i-C_(4)H_(8) and 1,3-C_(4)H_(6) from equimolar 1,3-C_(4)H_(6)/i-C_(4)H_(8),n-C_(4)H_(8)/i-C_(4)H_(8) and 1,3-C_(4)H_(6)/n-C_(4)H_(8)/i-C_(4)H_(8) mixtures.展开更多
All-inorganic and earth-abundant bi-/trimetallic hydr(oxy)oxides are widely used as oxygen evolution electrocatalysts owing to their remarkable performance.However,their atomically precise structures remain undefined,...All-inorganic and earth-abundant bi-/trimetallic hydr(oxy)oxides are widely used as oxygen evolution electrocatalysts owing to their remarkable performance.However,their atomically precise structures remain undefined,complicating their optimization and limiting the understanding of their enhanced performance.Here,the underlying structure-property correlation is explored by using a well-defined cobalt-phosphate polyoxometalate cluster [{(Co4)(OH)3(PO4)}4(SiW9 O34)4]^32-(1),which may serve as a molecular model of multimetal hydr(oxy)oxides.The catalytic activity is enhanced upon replacing Co by Fe in 1,resulting in a reduced overpotential(385 mV) for oxygen evolution(by 66 mV) compared to that of the parent 1 at 10 mA cm^-2 in an acidic medium;this overpotential is comparable to that for the IrO2 catalyst These abundant-metal-based polyoxometalates exhibit high stability,with no evidence of degradation even after 24 h of operation.展开更多
Two novel 3-D coordination compounds, Nd2[C6（COO）6]（H2O）6 （1）and Ho2[C6（COO）6]（H2O）6 （2）, were hydrothermaily synthesized from mellitic acid and neodymium perchlorate （or holmium perchlorate） in the alka...Two novel 3-D coordination compounds, Nd2[C6（COO）6]（H2O）6 （1）and Ho2[C6（COO）6]（H2O）6 （2）, were hydrothermaily synthesized from mellitic acid and neodymium perchlorate （or holmium perchlorate） in the alkaline aqueous solution and characterized with elemental analysis, TG, IR spectrum, and single crystal X-ray diffraction. The two compounds were isostructural and crystallized in the orthorhombic system, space group Pnnm, with a=1.3531 （4） nm, b=0.6687 （2） nm, c=1.0224（3） nm, V=0.92523（5） nm^3, Z=4, D=2.630 g/cm^3, F（000）=696.0, Goof=1.052. Final R indices [1 〉2∑（Ⅰ）]： R1=0.0195, wR2=0.0382 for 1; a=1.3411 （2） nm, b=0.6586（1） nm, c=1.0116（2） nm, V=0.8935（3） nm^3, Z=4, D=2.877 g/cm^3, F（000）=724.0, Goof=1.061. Final R indices [1 〉2∑（Ⅰ）]： R1=0.0200, wR2=0.0479 for 2. In the two compounds 1 and 2, the mellitic acid ligand, in which all the carboxylate groups were deprotonated, had only one kind of coordination mode to bridge metal ions to form four-connected three-dimensional diamondiod networks.展开更多
SiO_(2)is the major mineral substance in the upper mantle of the earth.Therefore,studies of the silica-coated materials under high-pressure are essential to explore the physical and chemical properties of the upper ma...SiO_(2)is the major mineral substance in the upper mantle of the earth.Therefore,studies of the silica-coated materials under high-pressure are essential to explore the physical and chemical properties of the upper mantle.The silica-confined CsPbBr_(3)nanocrystals(NCs)have recently attracted much attention because of the improved photoluminescence(PL)quantum yield,owing to the protection of silica shell.However,it remains considerable interest to further explore the relationship between optical properties and the structure of CsPbBr_(3)@SiO_(2)NCs.We systemically studied the structural and optical properties of the CsPbBr_(3)@SiO_(2)NCs under high pressure by using diamond anvil cell(DAC).The discontinuous changes of PL and absorption spectra occurred at~1.40 GPa.Synchrotron X-ray diffraction(XRD)studies of CsPbBr_(3)@SiO_(2)NCs under high pressure indicated an isostructural phase transformation at about 1.36 GPa,owing to the pressure-induced tilting of the Pb-Br octahedra.The isothermal bulk moduli for two phases are estimated about 60.0 GPa and 19.2 GPa by fitting the equation of state.Besides,the transition pressure point of CsPbBr_(3)@SiO_(2)NCs is slightly higher than that of pristine CsPbBr_(3)NCs,which attributed to the buffer effect of coating silica shell.The results indicate that silica shell is able to enhance the stabilization without changing the relationship between optical properties and structure of CsPbBr_(3)NCs.Our results were fascinated to model the rock metasomatism in the upper mantle and provided a new‘lithoprobe’for detecting the upper mantle.展开更多
An isostructural family of three dodecanuclear chiral M_(4)Cu_(8)(M=Dy,Y)complexes has been synthesized by adopting a mixed-ligand strategy,wherein one of the constituent linkers,pyroglutamic acid,a recognized biomole...An isostructural family of three dodecanuclear chiral M_(4)Cu_(8)(M=Dy,Y)complexes has been synthesized by adopting a mixed-ligand strategy,wherein one of the constituent linkers,pyroglutamic acid,a recognized biomolecule,has been credibly functioning as the chiral precursor imparting the chirality to the aforementioned complex.The highly symmetric new-fangled M_(4)Cu_(8)coordination-core,comprising of four square-symmetrically coordinated Dy/Y-vertex sharing M_(2)Cu_(2)cubane units,has been synthesized as an unprecedented discrete coordination complex,which has been analysed by magnetic measurements.展开更多
In this work,we report three isostructural Fe_(4)Ln_(4)wheel type complexes with molecular formula[{Fe_(4)(dea)_(4)Dy_(4)(deaH)8(μ2-OMe)_(4)}(NO_(3))_(4)]·4(H_(2)O)(1),[{Fe_(4)(dea)_(4)Gd_(4)(deaH)8(μ2-OMe)_(4)...In this work,we report three isostructural Fe_(4)Ln_(4)wheel type complexes with molecular formula[{Fe_(4)(dea)_(4)Dy_(4)(deaH)8(μ2-OMe)_(4)}(NO_(3))_(4)]·4(H_(2)O)(1),[{Fe_(4)(dea)_(4)Gd_(4)(deaH)8(μ2-OMe)_(4)}·(NO_(3))_(4)]·_(4)(H_(2)O)·_(4)(MeOH)(2)and[{Fe_(4)(dea)_(4)Y_(4)(deaH)_(8)(μ2-OMe)_(4)}(NO_(3))_(4)]·_(4)(H_(2)O)·6(MeOH)(3),(where dea=diethanolamine).Detailed structural analysis discloses that the_(4)Ln^(Ⅲ)and_(4)Fe^(Ⅲ)ions are connected alternatively in a cyclic arrangement through the oxo-bridging of methanol and diethanolamine molecules.The detailed magnetic measurements reveal the presence of ferromagnetic exchange interactions between the Ln^(Ⅲ)and Fe^(Ⅲ)centers in complexes 1 and 2,whereas a weak antiferromagnetic interaction is observed between Fe^(Ⅲ)centers in complex 3.In addition,complex 1 shows slow magnetic relaxation behavior(U_(eff)=9.8 K)under zero field and a remarkable entropy change was observed for complex 2 at 7 T magnetic field(magnetocaloric effect=31.15 J kg^(−1)K^(−1)).The ab initio calculations disclose the presence of strong axial anisotropy and a minimum transverse component(gx=0.002_(4),gy=0.0062,and gz=19.82)in the ground state of each Dy^(Ⅲ)ion for complex 1.It was also found that the local anisotropy axis on each Dy^(Ⅲ)ion is arranged in a vortex-like structure as observed in single molecule toroics(SMTs).From BS-DFT calculations,it was found that the exchange interactions between Fe-Ln metal centers mainly follow the charge transfer process between 3d and_(4)f orbitals.展开更多
The formation of heterometallic clusters usually involves a much more complex self-assembly process than that of homometallic clusters.Thus the tracking of their assembly mechanism is challenging.To achieve this task,...The formation of heterometallic clusters usually involves a much more complex self-assembly process than that of homometallic clusters.Thus the tracking of their assembly mechanism is challenging.To achieve this task,we designed one OH-containing Schiff base ligand of 1-[[(2-hydroxyethyl)imino]methyl]-2-naphthalenol(H_(2)L)with coordination pockets facile for selective coordination with CoII/NiII and 4f metal ions.Its reactions with the corresponding metal ions gave two new isostructural dodecanuclear complexes[Dy_(4)Co_(8)(μ_(3)-OH)_(8)(L)_(8)(OAc)_(4)(H_(2)O)_(4)]·3EtOH·3CH_(3)CN·H_(2)O(1)and[Dy_(4)Ni_(8)(μ_(3)-OH)_(8)(L)_(8)(OAc)_(4)(H_(2)O)_(4)]·3.5EtOH·0.5CH_(3)CN·5H_(2)O(2),which feature a vertex-sharing tetracubane cyclic skeleton with the four DyIII ions wrapped by the eight 3d metal ions.High-resolution electrospray mass spectrometry(HRESI-MS)tests showed that the skeletons of clusters 1 and 2 have high stability even under gradually increasing energy of the ion source.Most notably,the intermediates formed in the reaction courses for clusters 1 and 2 were tracked using time-dependent HRESI-MS,which gave different proposed assembly mechanisms for 1(H_(2)L→DyL→DyCoL→Dy_(2)CoL→Dy_(3)CoL→Dy_(4)CoL_(2)→Dy_(4)Co_(2)L_(3)→Dy_(4)Co_(4)L_(4)→Dy_(4)Co_(8)L_(8))and 2(H_(2)L→NiL→Dy_(2)NiL_(2)→Dy_(3)NiL_(2)→Dy_(4)NiL_(2)→Dy_(4)Ni_(2)L_(3)→Dy_(4)Ni_(4)L_(3)→Dy_(4)Ni_(6)L_(4)→Dy_(4)Ni_(8)L_(8)),respectively.This is the first time that different assembly mechanisms for isostructural heterometallic complexes are shown.Detailed magnetic studies revealed the absence of slow magnetic relaxation for 1 and the presence of slow magnetic relaxation for 2 with an energy barrier of 7.66 K and a pre-exponential factor of 1.45×10^(-6) s.The different magnetic performances of the two title complexes might be caused by the different metal ions of Co_((II))and Ni_((II)).展开更多
Two isostructural coordination polymers based on Co(Ⅱ)and Ni(Ⅱ),{[M(azpy)_(3)(p-bdc)_(2)(H_(2)O)_(4)]·(CH_(3)OH)_(2)(-H_(2)O)_(3)}n[where M=Co(1)and Ni(2);azpy=N,N’-bis-pyridin-4-ylmethylene-hydrazine and p-bd...Two isostructural coordination polymers based on Co(Ⅱ)and Ni(Ⅱ),{[M(azpy)_(3)(p-bdc)_(2)(H_(2)O)_(4)]·(CH_(3)OH)_(2)(-H_(2)O)_(3)}n[where M=Co(1)and Ni(2);azpy=N,N’-bis-pyridin-4-ylmethylene-hydrazine and p-bdc=1,4-benzenedicarboxylate],have been synthesized using mixed ligand systems at room temperature and characterized by single-crystal X-ray diffraction and other physicochemical methods.Structure determination reveals that both the complexes crystallize in the monoclinic space group C2/c and exhibit one-dimensional(1D)ladder like structures constructed by p-bdc and azpy ligands in which Schiff base(azpy)linkers serve as a bridging as well as pendent ligands.These pendent ligands are involved in H-bonding and π-π interactions with lattice water,methanol molecules and bridging azpy ligands,to form the 3D supramolecular structure.Notably,both the frameworks efficiently catalyze the Knoevenagel condensation reactions of a wide range of substituted benzaldehydes with active methylene compounds in heterogeneous medium under environmentally friendly conditions and the products were obtained in excellent yields.These catalysts were also found to exhibit excellent recyclability and re-usability without any significant loss of activity.A variable temperature magnetic study of both compounds was carried out and their magnetic properties justified on the basis of their crystal structure.展开更多
Molecular materials are playing a pivotal role in the advancement of prospective THz technologies.Herein,we have prepared nine isostructural coordination complexes of general formula[Ln^(Ⅲ)(H_(2)O)_(3)][AgI(CN)_(2)]_...Molecular materials are playing a pivotal role in the advancement of prospective THz technologies.Herein,we have prepared nine isostructural coordination complexes of general formula[Ln^(Ⅲ)(H_(2)O)_(3)][AgI(CN)_(2)]_(3)(LnAg,Ln=La,Ce,Pr,Nd,Sm,Eu,Gd,Tb,and Dy).Vibrational spectroscopy has unveiled gradual changes in theν(CuN)stretching frequencies within both infrared(IR)and Raman spectra from LaAg to DyAg,stemming from incremental alterations in crystallographic unit cell parameters and volumes.Similarly,the THz spectra manifest pronounced absorption signals between 1.0 to 1.2 THz,which can be judiciously tuned by varying lanthanide(^(Ⅲ))ion and measurement temperature.Ab initio density-functional theory(DFT)calculations of THz spectra elucidate the primary contribution from opposite translational vibrations of Ag atoms and O atoms from H_(2)O around Ln(^(Ⅲ))atoms.Furthermore,thin films of LnAg can achieve a large return loss in a broad bandwidth in impedance-matching simulations.展开更多
基金supports from the National Key Research and Development Program of China(2022YFE03170002)the National Natural Science Foundation of China(52071286 and U2030208).
文摘The launch of International Thermonuclear Experimental Reactor project paves the way to wide adoption of DT fusion energy as future energy source.Efficient fuel cycle to minimize strategic tritium inventory proves crucial for commercially viable fusion technologies.ZrCo alloy is considered as a promising candidate for fast isotope handling.However,cycling degradation caused by hydrogen-induced disproportionation results in severe tritium trapping,thus impeding its practical application.Herein,an isostructural transition is successfully constructed with low hysterisis,ameliorated plateau flatness of pressure-composition isotherms and improved high-temperature durability for hydrogen trapping minimization.Specifically,the optimal Zr_(0.7)Hf_(0.15)Nb_(0.15)Co_(0.6)Cu_(0.15)Ni_(0.25) alloy adopts Hf-Nb and Cu-Ni as Zr and Co side doping elements,exhibiting substantial thermodynamic destabilization with nearly 90℃ reduction of delivery temperature,and significant kinetic promotion with a threefold lower energy barrier.More importantly,both hydrogen utilization and cycling retention of optimal alloy are increased by about twenty times compared with pristine alloy after 100 cycles at 500℃.Minimized disproportionation driving force from both isostructural transition and suppressed 8e hydrogen occupation realizes full potential of optimal alloy.This work demonstrates the effectiveness of combining isostructural transformation and high-temperature durability improvement to enhance the hydrogen utilization of ZrCo-based alloys and other hydrogen storage materials.
基金the strategic priority Research Program(B)of the Chinese Academy of Sciences(Grant No.18010401)Key Research Program of Frontier Sciences of CAS(Grant No.QYZDB-SSW-DQC009)+3 种基金Hundred Talents Program of CAS,NSF of China(Grant Nos.41774099 and 41772042)Youth Innovation Promotion Association of CAS(Grant No.2019390)Special Fund of the West Light Foundation of CASthe Supercomputer Center of Fujian Institute of Research on the Structure of Matter(FJIRSM)is acknowledged.
文摘The high-pressure structural,vibrational and electrical properties for realgar were investigated by in-situ Raman scattering and electrical conductivity experiments combined with first-principle calculations up to~30.8 GPa.It was verified that realgar underwent an isostructural phase transition at~6.3 GPa and a metallization at a higher pressure of~23.5 GPa.The isostructural phase transition was well evidenced by the obvious variations of Raman peaks,electrical conductivity,crystal parameters and the As–S bond length.The phase transition of metallization was in closely associated with the closure of bandgap rather than caused by the structural phase transition.And furthermore,the metallic realgar exhibited a relatively low compressibility with the unit cell volume V_(0)=718.1.4Å^(3)and bulk modulus B_(0)=36.1 GPa.
基金Project supported by the National Key Research and Development Program of China(Grant No.2018YFA0305900)the National Natural Science Foundation of China(Grant Nos.11874172,11374120,11634004,and 51320105007)the Fund from Jilin University for Science and Technology Innovative Research Team(Grant No.2017TD-01)
文摘High pressure structural phase transition of monoclinic paraotwayite type α-Ni(OH)2 nanowires with a diameter of15 nm–20 nm and a length of several micrometers were studied by synchrotron x-ray diffraction(XRD) and Raman spectra.It is found that the α-Ni(OH)2 nanowires experience an isostructural phase transition associated with the amorphization of the H-sublattice of hydroxide in the interlayer spaces of the two-dimensional crystal structure at 6.3 GPa–9.3 GPa. We suggest that the isostructural phase transition can be attributed to the amorphization of the H-sublattice. The bulk moduli for the low pressure phase and the high pressure phase are 41.2(4.2) GPa and 94.4(5.6) GPa, respectively. Both the pressure-induced isostructural phase transition and the amorphization of the H-sublattice in the α-Ni(OH)2 nanowires are reversible upon decompression. Our results show that the foreign anions intercalated between the α-Ni(OH)2 layers play important roles in their structural phase transition.
基金financially supported by the Key R&D Project of Hebei Province (No. 21282602Z)Shandong Province (No. 2020CXGC010506)the Innovative Group Project (No. 21621004)。
文摘Isostructural multicomponent crystals provide a promising way for fine-tuning physicochemical properties, whereas their design remains quite challenging. The purpose of this work was to provide a new strategy for obtaining isostructural multicomponent crystals by introducing coformers with functional group positional isomerism. Five isostructural salts of an antitumor drug dimethylaminomicheliolide(DMAMCL) were reported and designed with a series of dihydroxybenzoic acid regioisomers for the first time, which were identified by power and single-crystal X-ray diffractions. Similar lattice parameters suggested these obtained salts may have the same crystal packing mode. The quantitative similarity parameters via XPac, Crystal CMP and Mercury program further proved these crystal structures are3D isostructural. Hirshfeld surface maps and 2D fingerprint plots show that the isostructural salts have similar intermolecular interactions. Compared with DMAMCL, obvious improvement was observed in the thermal stability, hygroscopicity, and solubility of these isostructural salts. Meanwhile, isostructural crystals may have different physicochemical properties, even though the shape and molecular size are similar and the packing of crystal structures is equally matched.
基金supported by the National Natural Science Foundation of China(NSFC no.21101064 and 21971069).
文摘The electrochemical enantiorecognition of amino acids has wide applications,but the creation of the required uniform and homochiral microenvironments at electrodes remains a huge challenge.With highly ordered and adjustable structures,homochiral MOFs may provide nice platforms for fine regulation of the microenvironments.Herein,we report for the first time the distinct enantiodiscriminative abilities controlled by metal centers in isostructural homochiral MOFs.Cu-TBLeuBpa,which has a L-leucine-derived linker with Cu_((II))in a severely elongated octahedron,displays highly efficient enantiomeric discrimination of Tyr and Trp,with high current ratios(I_(L)/I_(D),up to 9.83),large potential differences(EL-ED,up to 160 mV),and ultralow detection limits for the L-isomers(2-4 nM).The overall performance is remarkably superior to previous sensors for these amino acids.The Cu-TBLeuBpa sensor has been successfully utilized for the quantitative assay of L-Tyr and L-Trp in racemic mixtures and human urine.We demonstrated that not only the chiral aliphatic amino acid moiety but also the achiral aromatic moiety(phenol or indole)plays a decisive role in the biased adsorption and electrochemical recognition of the L isomers.In contrast,the isostructural Co-TBLeuBpa,in which Co(II)shows a quasi-regular octahedron,is unable to distinguish Tyr enantiomers and shows weakened but still conspicuous performance for Trp enantiomers.This work highlights that a small alteration of the metal geometry in MOFs can have a significant or even decisive impact on enantiorecognition,opening up new perspectives for the design of chiral sensing materials.
基金financial support from the National Natural Science Foundation of China(No.21601109).
文摘A family of isostructural heterometallic MOFs based on Fe_(2)M clusters(MOF-Fe_(2)M;M=Fe,Co and Ni,respectively)have been synthesized and serve as potential proton conductors and photocatalysts for CO_(2)photoreduction,exhibiting varied proton conductivities and photocatalytic performances.
基金support from the National Key Basic Research Program of China(2013CB933403)the National Natural Science Foundation of China(21471154 and 91022014)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB12010103).
文摘Two isostructural dense lanthanide metal-organic frameworks derived from an extended ligand 1,3,5-tris(4-carboxyphenyl)benzene(H3BTB),[Ln(BTB)H_(2)O]n(Ln=Eu,1;Ln=Dy,2),which are constructed via a cross-like folding assembly strategy,were yielded by‘two-step warming solvothermal synthesis’.Complex 1 shows luminescence while complex 2 exhibits field-induced two-step magnetic relaxation.
基金financially supported by the National Natural Science Foundation of China(21971240 and 22201037)the Natural Science Foundation of Fujian Province(2021J01106).
文摘The design and development of advanced hypergolic metal–organic frameworks(HMOFs)for space exploration have attracted widespread attention in recent years.However,enhancing the energy densities and elucidating the relationship between the structure and hypergolic properties of HMOFs are still in their infancy.
基金National Natural Science Foundation of China,Grant/Award Numbers:22279061,21901120,21371098The Fundamental Research Funds for the Central Universities,the Natural Science Foundation of Jiangsu Province,Grant/Award Numbers:BK20180514,BK20190503,BK20131314+1 种基金The Qing Lan Project of Jiangsu Province.Q.Z.thanks the funding support from City University of Hong Kong,Grant/Award Numbers:9380117,7005620 and 7020040Hong Kong Institute for Advanced Study,City University of Hong Kong,China。
文摘The performance of asymmetric supercapacitors(ASCs)is strongly restricted by the capacity gap between the positive and negative electrodes.To address this issue,two new electrode materials deriving from Co‐and Fe‐based metal–organic frameworks(MOFs,Co‐TAMBA‐d,and Fe‐TAMBA‐d)through a single‐step sintering method have been developed by considering the superiorities of the derivatives of MOFs including large surface areas,sufficient metal‐atom‐doping content,and extreme surface wettability to the bath solution.The as‐prepared Co‐TAMBA‐d as a positive electrode delivers typical pseudocapacitive behavior with the improvement of capacity,which is better than those of pristine MOF materials,while Fe‐TAMBA‐d as negative electrodes displays better electrochemical behavior than those of activated carbon.ASCs based on these two electrodes exhibits excellent energy density and power density of 47Wh/kg and 1658 W/kg,respectively,where this device can maintain prominent cycling stability with capacity retention after 5000 cycles being about 75%.Furthermore,the capacity can feed a series of red light‐emitting diodes,which gives solid evidence of the potential utilization.These results can afford the feasibility of isostructural MOF derivatives as promising electrodes in novel ASCs.
文摘The relation between cell-edges or unit-cell volumes of isostructural compounds and theionic radii has wide applications in crystal chemistry. The authors have proved: (1) For a series of multiple isostructural compounds such as A_mB_n…X_p, when the anionand other cations are fixed, there exists the following relation between the unit-cell volume Vand the radius r_A of a certain cation such as A: V = (a + br_A)(r_X + r_A)~3 (a and b are constants). (2) For binary isostructural compounds A_mX_p, the above relation is reduced to V = k(r_X + r_A)~3 (k is a constant). (3) For binary isostructural compounds the relation between V and r_A^3 is approximatelylinear, and for multiple compounds, it is often curvilinear but still approximately linear whenthe variation of r_A is slight. As another approximation, a linear relation also exists betweenV and r_A for isostructural compounds. (4) The relation of ce1l-edge a vs. r_A is linear for binary isostructural compounds. Butno such a good linear relation exists for multiple isostructural compounds.
基金supported by the National Natural Science Foundation of China(21703247)the Science Foundation of Fujian Province(2018J05029,2019J05156,2019H0053)。
文摘Three new isostructural coordination polymers,namely,[Mg(cpna)(H2O)2]n(1),[Mn(cpna)(H_(2)O)_(2)]n(2)and[Co(cpna)(H_(2)O)_(2)]n(3)(H_(2) cpna=5-(3-carboxylphenyl)nicotic acid)are reported.They were synthesized by hydrothermal reactions of transition metal or alkaline earth metal chloride with 5-(3-carboxylphenyl)nicotic acid,respectively.Complexes 1~3 exhibit 2D layers with a 3,3-connected topology with Schl?fli symbol{4.82}.Such layers including hexagonal rings and a quadrangular ring are further extended into an ordered 3D framework by hydrogen bonds between the cpna2-ligands and water molecules.The rare complex 1 has excellent luminescence and can be used as luminescent materials,while 2 and 3 possess prominent magnetism with potential applications in magnetic materials.
基金supported by National Natural Science Foundation of China(22090061,22375221)Fundamental Research Program of Shanxi Province(No.202203021223004)+1 种基金Program for Guangdong Introducing Innovative and Entrepreneurial Teams(2017ZT07C069)Hundred Talents Program of Sun Yat-Sen University.
文摘Separation of ternary C_(4) olefins(n-butene,iso-butene and 1,3-butadiene)is very challenging but crucial in the petrol-chemical industry due to their similar molecular sizes and properties.Herein,to optimize the separation efficiency for separation of C_(4) olefins,a new Hofmann-type MOF,[Ni(piz)Ni(CN)_(4)](piz=piperazine)-isostructural to the typical one[Ni(pyz)Ni(CN)_(4)](pyz=pyrazine),has been synthesized by a facile method from aqueous solution.The pore size reduction of[Ni(piz)Ni(CN)_(4)](3.62A,in contrast to 3.85A in[Ni(pyz)Ni(CN)_(4)])results in negligible iso-butene(i-C_(4)H_(8))uptake(from 2.92 to 0.04 mmol g^(-1))whereas retaining significant uptake for 1,3-butadiene(1,3-C_(4)H_(6),1.96 mmol g^(-1))and n-butene(n-C_(4)H_(8),1.47 mmol g^(-1)),showing much higher uptake ratios of 1,3-C_(4)H_(6)/i-C_(4)H_(8)(47)and n-C_(4)H_(8)/i-C_(4)H_(8)(35)that outperform most of the benchmark porous materials for separating C_(4) olefins.Breakthrough experiments demonstrate successful separation of high-purity(99.9999%)i-C_(4)H_(8) and 1,3-C_(4)H_(6) from equimolar 1,3-C_(4)H_(6)/i-C_(4)H_(8),n-C_(4)H_(8)/i-C_(4)H_(8) and 1,3-C_(4)H_(6)/n-C_(4)H_(8)/i-C_(4)H_(8) mixtures.
文摘All-inorganic and earth-abundant bi-/trimetallic hydr(oxy)oxides are widely used as oxygen evolution electrocatalysts owing to their remarkable performance.However,their atomically precise structures remain undefined,complicating their optimization and limiting the understanding of their enhanced performance.Here,the underlying structure-property correlation is explored by using a well-defined cobalt-phosphate polyoxometalate cluster [{(Co4)(OH)3(PO4)}4(SiW9 O34)4]^32-(1),which may serve as a molecular model of multimetal hydr(oxy)oxides.The catalytic activity is enhanced upon replacing Co by Fe in 1,resulting in a reduced overpotential(385 mV) for oxygen evolution(by 66 mV) compared to that of the parent 1 at 10 mA cm^-2 in an acidic medium;this overpotential is comparable to that for the IrO2 catalyst These abundant-metal-based polyoxometalates exhibit high stability,with no evidence of degradation even after 24 h of operation.
基金supported by the Nature Science Foundation of Guangdong Province (7005808)Guangdong Provincial Science and Technology Bureau (2008B010600009)the National Natural Science Foundation of China (U0734005)
文摘Two novel 3-D coordination compounds, Nd2[C6（COO）6]（H2O）6 （1）and Ho2[C6（COO）6]（H2O）6 （2）, were hydrothermaily synthesized from mellitic acid and neodymium perchlorate （or holmium perchlorate） in the alkaline aqueous solution and characterized with elemental analysis, TG, IR spectrum, and single crystal X-ray diffraction. The two compounds were isostructural and crystallized in the orthorhombic system, space group Pnnm, with a=1.3531 （4） nm, b=0.6687 （2） nm, c=1.0224（3） nm, V=0.92523（5） nm^3, Z=4, D=2.630 g/cm^3, F（000）=696.0, Goof=1.052. Final R indices [1 〉2∑（Ⅰ）]： R1=0.0195, wR2=0.0382 for 1; a=1.3411 （2） nm, b=0.6586（1） nm, c=1.0116（2） nm, V=0.8935（3） nm^3, Z=4, D=2.877 g/cm^3, F（000）=724.0, Goof=1.061. Final R indices [1 〉2∑（Ⅰ）]： R1=0.0200, wR2=0.0479 for 2. In the two compounds 1 and 2, the mellitic acid ligand, in which all the carboxylate groups were deprotonated, had only one kind of coordination mode to bridge metal ions to form four-connected three-dimensional diamondiod networks.
基金the National Science Foundation of China(Grant Nos.21725304,11774125,and 21673100)the Chang Jiang Scholars Program of China(Grant No.T2016051)+3 种基金Changbai Mountain Scholars Program(Grant No.2013007)National Defense Science and Technology Key Laboratory Fund(Grant No.6142A0306010917)Jilin Provincial Science&Technology Development Program(Grant No.20190103044JH)Scientific Research Planning Project of the Education Department of Jilin Province(Grant No.JJKH20180118KJ)。
文摘SiO_(2)is the major mineral substance in the upper mantle of the earth.Therefore,studies of the silica-coated materials under high-pressure are essential to explore the physical and chemical properties of the upper mantle.The silica-confined CsPbBr_(3)nanocrystals(NCs)have recently attracted much attention because of the improved photoluminescence(PL)quantum yield,owing to the protection of silica shell.However,it remains considerable interest to further explore the relationship between optical properties and the structure of CsPbBr_(3)@SiO_(2)NCs.We systemically studied the structural and optical properties of the CsPbBr_(3)@SiO_(2)NCs under high pressure by using diamond anvil cell(DAC).The discontinuous changes of PL and absorption spectra occurred at~1.40 GPa.Synchrotron X-ray diffraction(XRD)studies of CsPbBr_(3)@SiO_(2)NCs under high pressure indicated an isostructural phase transformation at about 1.36 GPa,owing to the pressure-induced tilting of the Pb-Br octahedra.The isothermal bulk moduli for two phases are estimated about 60.0 GPa and 19.2 GPa by fitting the equation of state.Besides,the transition pressure point of CsPbBr_(3)@SiO_(2)NCs is slightly higher than that of pristine CsPbBr_(3)NCs,which attributed to the buffer effect of coating silica shell.The results indicate that silica shell is able to enhance the stabilization without changing the relationship between optical properties and structure of CsPbBr_(3)NCs.Our results were fascinated to model the rock metasomatism in the upper mantle and provided a new‘lithoprobe’for detecting the upper mantle.
基金DST(project no.GAP/DST/CHE-12-0083)is acknowledged for the financial supportDST-FIST(SR/FST/CSII-023/2012)is acknowledged for micro-focus SC-XRD facility.
文摘An isostructural family of three dodecanuclear chiral M_(4)Cu_(8)(M=Dy,Y)complexes has been synthesized by adopting a mixed-ligand strategy,wherein one of the constituent linkers,pyroglutamic acid,a recognized biomolecule,has been credibly functioning as the chiral precursor imparting the chirality to the aforementioned complex.The highly symmetric new-fangled M_(4)Cu_(8)coordination-core,comprising of four square-symmetrically coordinated Dy/Y-vertex sharing M_(2)Cu_(2)cubane units,has been synthesized as an unprecedented discrete coordination complex,which has been analysed by magnetic measurements.
基金the SRF fellowship and S.K.thanks CSIR(project no.01(2974)/19/EMR-II)SERB(project no.CRG/2018/000072)Government of India and IISER Bhopal for generous financial support.
文摘In this work,we report three isostructural Fe_(4)Ln_(4)wheel type complexes with molecular formula[{Fe_(4)(dea)_(4)Dy_(4)(deaH)8(μ2-OMe)_(4)}(NO_(3))_(4)]·4(H_(2)O)(1),[{Fe_(4)(dea)_(4)Gd_(4)(deaH)8(μ2-OMe)_(4)}·(NO_(3))_(4)]·_(4)(H_(2)O)·_(4)(MeOH)(2)and[{Fe_(4)(dea)_(4)Y_(4)(deaH)_(8)(μ2-OMe)_(4)}(NO_(3))_(4)]·_(4)(H_(2)O)·6(MeOH)(3),(where dea=diethanolamine).Detailed structural analysis discloses that the_(4)Ln^(Ⅲ)and_(4)Fe^(Ⅲ)ions are connected alternatively in a cyclic arrangement through the oxo-bridging of methanol and diethanolamine molecules.The detailed magnetic measurements reveal the presence of ferromagnetic exchange interactions between the Ln^(Ⅲ)and Fe^(Ⅲ)centers in complexes 1 and 2,whereas a weak antiferromagnetic interaction is observed between Fe^(Ⅲ)centers in complex 3.In addition,complex 1 shows slow magnetic relaxation behavior(U_(eff)=9.8 K)under zero field and a remarkable entropy change was observed for complex 2 at 7 T magnetic field(magnetocaloric effect=31.15 J kg^(−1)K^(−1)).The ab initio calculations disclose the presence of strong axial anisotropy and a minimum transverse component(gx=0.002_(4),gy=0.0062,and gz=19.82)in the ground state of each Dy^(Ⅲ)ion for complex 1.It was also found that the local anisotropy axis on each Dy^(Ⅲ)ion is arranged in a vortex-like structure as observed in single molecule toroics(SMTs).From BS-DFT calculations,it was found that the exchange interactions between Fe-Ln metal centers mainly follow the charge transfer process between 3d and_(4)f orbitals.
基金supported by the National Natural Science Foundation of China(grant no.12064002,22061004 and 21901050)the Guangxi Natural Science Foundation of China(grant no.2018GXNSFBA050031 and 2020GXNSFAA159132)+1 种基金the Guangxi Technology Base and Talent Subject(grant no.GUIKE AD19245002)the Key Project of Guangxi Normal University(grant no.2018ZD003).
文摘The formation of heterometallic clusters usually involves a much more complex self-assembly process than that of homometallic clusters.Thus the tracking of their assembly mechanism is challenging.To achieve this task,we designed one OH-containing Schiff base ligand of 1-[[(2-hydroxyethyl)imino]methyl]-2-naphthalenol(H_(2)L)with coordination pockets facile for selective coordination with CoII/NiII and 4f metal ions.Its reactions with the corresponding metal ions gave two new isostructural dodecanuclear complexes[Dy_(4)Co_(8)(μ_(3)-OH)_(8)(L)_(8)(OAc)_(4)(H_(2)O)_(4)]·3EtOH·3CH_(3)CN·H_(2)O(1)and[Dy_(4)Ni_(8)(μ_(3)-OH)_(8)(L)_(8)(OAc)_(4)(H_(2)O)_(4)]·3.5EtOH·0.5CH_(3)CN·5H_(2)O(2),which feature a vertex-sharing tetracubane cyclic skeleton with the four DyIII ions wrapped by the eight 3d metal ions.High-resolution electrospray mass spectrometry(HRESI-MS)tests showed that the skeletons of clusters 1 and 2 have high stability even under gradually increasing energy of the ion source.Most notably,the intermediates formed in the reaction courses for clusters 1 and 2 were tracked using time-dependent HRESI-MS,which gave different proposed assembly mechanisms for 1(H_(2)L→DyL→DyCoL→Dy_(2)CoL→Dy_(3)CoL→Dy_(4)CoL_(2)→Dy_(4)Co_(2)L_(3)→Dy_(4)Co_(4)L_(4)→Dy_(4)Co_(8)L_(8))and 2(H_(2)L→NiL→Dy_(2)NiL_(2)→Dy_(3)NiL_(2)→Dy_(4)NiL_(2)→Dy_(4)Ni_(2)L_(3)→Dy_(4)Ni_(4)L_(3)→Dy_(4)Ni_(6)L_(4)→Dy_(4)Ni_(8)L_(8)),respectively.This is the first time that different assembly mechanisms for isostructural heterometallic complexes are shown.Detailed magnetic studies revealed the absence of slow magnetic relaxation for 1 and the presence of slow magnetic relaxation for 2 with an energy barrier of 7.66 K and a pre-exponential factor of 1.45×10^(-6) s.The different magnetic performances of the two title complexes might be caused by the different metal ions of Co_((II))and Ni_((II)).
基金the financial assistance given by CSIR,Govt.of India(grant to DG)UGC for the research fellowship.
文摘Two isostructural coordination polymers based on Co(Ⅱ)and Ni(Ⅱ),{[M(azpy)_(3)(p-bdc)_(2)(H_(2)O)_(4)]·(CH_(3)OH)_(2)(-H_(2)O)_(3)}n[where M=Co(1)and Ni(2);azpy=N,N’-bis-pyridin-4-ylmethylene-hydrazine and p-bdc=1,4-benzenedicarboxylate],have been synthesized using mixed ligand systems at room temperature and characterized by single-crystal X-ray diffraction and other physicochemical methods.Structure determination reveals that both the complexes crystallize in the monoclinic space group C2/c and exhibit one-dimensional(1D)ladder like structures constructed by p-bdc and azpy ligands in which Schiff base(azpy)linkers serve as a bridging as well as pendent ligands.These pendent ligands are involved in H-bonding and π-π interactions with lattice water,methanol molecules and bridging azpy ligands,to form the 3D supramolecular structure.Notably,both the frameworks efficiently catalyze the Knoevenagel condensation reactions of a wide range of substituted benzaldehydes with active methylene compounds in heterogeneous medium under environmentally friendly conditions and the products were obtained in excellent yields.These catalysts were also found to exhibit excellent recyclability and re-usability without any significant loss of activity.A variable temperature magnetic study of both compounds was carried out and their magnetic properties justified on the basis of their crystal structure.
基金financed in part by a JSPS Grant-in-Aid for Scientific Research(A)(Grant Number 20H00369),IRL DYNACOM(CNRS),the CNRS-University of Tokyo“Excellence Science”Joint Research Program,and the Second CNRS-University of Tokyo PhD Joint ProgramThe authors acknowledge the Cryogenic Research Center,The University of Tokyo,the Center for Nano Lithography&Analysis,The University of Tokyo supported by MEXT,and the MEXT Quantum Leap Flagship Program(Grant Number JPMXS0118068681)for the support.G.L.is grateful to JSPS KAKENHI(Grant Number 23KJ0736)+4 种基金O.S.is thankful to JSPS KAKENHI(Grant Number 21K14582)K.K.acknowledges a Grant-in-Aid for JSPS fellows(Grant Number 23K19238)Y.M.and L.W.thank the JST SPRING(Grant Number JPMJSP2108)K.N.recognizes the Iketani Science and Technology Foundation(Grant Number 0351111-A)M.Y.is grateful to JSPS Grant-in-Aid for Young Scientists(Grant Number JP24K17606)。
文摘Molecular materials are playing a pivotal role in the advancement of prospective THz technologies.Herein,we have prepared nine isostructural coordination complexes of general formula[Ln^(Ⅲ)(H_(2)O)_(3)][AgI(CN)_(2)]_(3)(LnAg,Ln=La,Ce,Pr,Nd,Sm,Eu,Gd,Tb,and Dy).Vibrational spectroscopy has unveiled gradual changes in theν(CuN)stretching frequencies within both infrared(IR)and Raman spectra from LaAg to DyAg,stemming from incremental alterations in crystallographic unit cell parameters and volumes.Similarly,the THz spectra manifest pronounced absorption signals between 1.0 to 1.2 THz,which can be judiciously tuned by varying lanthanide(^(Ⅲ))ion and measurement temperature.Ab initio density-functional theory(DFT)calculations of THz spectra elucidate the primary contribution from opposite translational vibrations of Ag atoms and O atoms from H_(2)O around Ln(^(Ⅲ))atoms.Furthermore,thin films of LnAg can achieve a large return loss in a broad bandwidth in impedance-matching simulations.
