A novel organotin complex [Ph3Sn（C2H5OH）（OCOC5H3NBr）SnPh3（OCOC5H3NBr）] has been synthesized by the reaction of 5-bromonicotinic acid with triphenyltin hydroxide in ethanol and characterized by elemental analysis...A novel organotin complex [Ph3Sn（C2H5OH）（OCOC5H3NBr）SnPh3（OCOC5H3NBr）] has been synthesized by the reaction of 5-bromonicotinic acid with triphenyltin hydroxide in ethanol and characterized by elemental analysis, IR and ^1H NMR. The crystal structure was determined by X-ray single-crystal diffraction. The crystal belongs to the monoclinic system, space group P21/c with a = 15.564（2）, b = 24.975（4）, c = 12.2973（19）°A, β = 92.224（2）°, Z = 4, V = 4776.5（13）°A^3, Dc = 1.596 g/cm^3, μ（MoKα） = 2.765 mm^-1, F（000） = 2264, R = 0.0385 and wR = 0.0667. In the molecular structure of the title complex, the tin atoms are five-coordinated in a trigonal bipyramidal geometry.展开更多
The reaction of 4-（p-fluobenzoyl）-2,5-dihydro-3-methyl-1-phenyl pyrazol-5-one with thiosemicarbazide in MeOH followed by recrystallization in EtOH gave rise to yellowish lamellar crystals of 4（p-fluo-a-aminothiocar...The reaction of 4-（p-fluobenzoyl）-2,5-dihydro-3-methyl-1-phenyl pyrazol-5-one with thiosemicarbazide in MeOH followed by recrystallization in EtOH gave rise to yellowish lamellar crystals of 4（p-fluo-a-aminothiocarbonyl hydrazonobenzal）-2,5-dihydro-3-methyl- 1-phenyl pyrazol-5-one 1. It crystallizes in orthorhombic, space group Pbca with a = 18.445（4）, b = 11.987（2）, c = 19.249（4） °A,, V= 4256.1（18）°A^3, Z = 8, Mr = 415.49, Dc= 1.297 g/cm^3, T = 296（2） K, F（000） = 1744,μ（MoKα） = 0.186 cm^-1, R = 0.0521 and wR = 0.1211 for 1661 observed reflections with I 〉 2σ（I）. The compound was structurally characterized by elemental analyses, IR and ^1H NMR. The intermolecular hydrogen bonds are present and a two-dimensional framework is formed by two intermolecular hydrogen bonds in the （001） plane.展开更多
The compound NdAlSi was studied using X-ray powder diffraction technique and refined by the Rietveld method. The compound NdAlSi has tetragonal α-ThSiE-type structure, space group I41/amd （No. 141）, Z = 4, and the ...The compound NdAlSi was studied using X-ray powder diffraction technique and refined by the Rietveld method. The compound NdAlSi has tetragonal α-ThSiE-type structure, space group I41/amd （No. 141）, Z = 4, and the lattice parameters a = 0.41991（1） nm, c = 1.44916（3） nm. The Smith and Snyder figure of merit FN is F30= 103.1（36）. The R-factors of Rietveld refinement are Rp= 0.113 and Rwp= 0.148, respectively. The X-ray powder diffraction data is presented in this article.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
Two new isostructure nickel（Ⅱ） coordination polymers, [Ni2（5-Me-ip）（1,2- Bie）（H2O）2]n （1） and [Ni2（5-Br-ip）（1,2-Bie）（H2O）2]n （2） （5-Me-H2ip = 5-methylisophthalic acid, 5-Br-H2ip = 5-mromoisophthali...Two new isostructure nickel（Ⅱ） coordination polymers, [Ni2（5-Me-ip）（1,2- Bie）（H2O）2]n （1） and [Ni2（5-Br-ip）（1,2-Bie）（H2O）2]n （2） （5-Me-H2ip = 5-methylisophthalic acid, 5-Br-H2ip = 5-mromoisophthalic acid, 1,2-Bie = 1,2-bis（imidazole）ethane）, have been synthesized and structurally characterized by single-crystal X-ray diffraction. The result shows that complexes 1 and 2 crystallize in orthorhombic system, space group Pna21 with a = 16.3602（13）, b = 10.1465（8）, c = 21.8803（17）A^°, V = 3632.1（5） A^°3, Z = 4, Dc = 1.525 g/cm3, F（000） = 1728, R = 0.0292 and wR = 0.0668 for 6646 observed reflections （I 〉 2σ（I）） for complex 1 and a = 16.409（3）, b = 10.1625（17）, c = 21.918（4）A^°, V = 3654.9（11） A^°3, Z = 4, Dc = 1.752 g/cm^3, F（000） = 1936, R = 0.0309 and wR = 0.0600 for 6809 observed reflections （I 〉 2σ（I）） for complex 2. They both feature zigzag 2D layer structures, which are further staked along the a-axis through π…π and hydrogen interactions to form 3D supramolecular structures.展开更多
Two new Cd（Ⅱ） coordination polymers, [Cd（PT）（1,4-BDC）0.5]n （1） and [Cd（PT） （1,3-BDC）0.5]n （2） （HPT = 3-（pyridin-2-yl）-1,2,4-triazole, 1,4-H2BDC = 1,4-benzenedicarboxylic acid, 1,3-H2BDC = 1,3-benzene...Two new Cd（Ⅱ） coordination polymers, [Cd（PT）（1,4-BDC）0.5]n （1） and [Cd（PT） （1,3-BDC）0.5]n （2） （HPT = 3-（pyridin-2-yl）-1,2,4-triazole, 1,4-H2BDC = 1,4-benzenedicarboxylic acid, 1,3-H2BDC = 1,3-benzenedicarboxylic acid）, have been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction as well as elemental analysis and IR. Complexes 1 and 2 are both three-dimensional coordination polymers with two-dimensional sheet structures bridged by the deprotonated carboxylate ligands. In 1, 1,4-BDC2- bridges the layered network to generate a quadrangular framework, and 2 owns a sexangular framework, which was caused by the different steric hindrance between 1,4-BDC^2- and 1,3-BDC^2-. Their thermal stabilities and photoluminescent properties have been also investigated.展开更多
KTb（WO4）2（KTW） single crystal with dimensions up to 30 mm×30 mm 10 mm was grown by the top-seeded solution growth （TSSG） method for the first time. The crystal structure was refined at room temperature by u...KTb（WO4）2（KTW） single crystal with dimensions up to 30 mm×30 mm 10 mm was grown by the top-seeded solution growth （TSSG） method for the first time. The crystal structure was refined at room temperature by using single crystal X-ray diffiaction data. Ab- sorption and fluorescence spectra were measured at room temperature. The fluorescence lifetime of KTb（WO4）2 was 114 μs. The specific heat of the KTh（WO4）2 crystal was also measured at room temperature.展开更多
A Yb_（0.11）Gd_（0.89）Ca_4O（BO_3）_3 crystal with new composition was grown by the Czochralski method. The crystal structure was measured and analyzed. The unit-cell parameters of the Yb_（0.11）Gd_（0.89）COB were...A Yb_（0.11）Gd_（0.89）Ca_4O（BO_3）_3 crystal with new composition was grown by the Czochralski method. The crystal structure was measured and analyzed. The unit-cell parameters of the Yb_（0.11）Gd_（0.89）COB were calculated to be a=0.8089（7） nm, b=1.5987（6） nm, c=0.3545（8） nm, β=101.22o. The absorption and fluorescence spectra were measured. The maximum absorption cross-section of Yb_（0.11）Gd_（0.89） COB crystal was 0.79×10^（–20）cm^2, which occurred at 976 nm with Y polarization. The emission cross-section at 1027 nm was calculated to be 0.33×10^（–20） cm^2. The radiative lifetime trad was calculated to be 2.74 ms. The Stark energy-level diagram of Yb^（3＋）in the Yb_（0.11）Gd_（0.89）COB crystal field at room temperature was determined. The ground-state energy level ~2F_（7/2） splitting was calculated to be as large as 1004 cm^（–1） and the zero-line energy was 10246 cm^（–1）. A maximum output power of 9.35 W was achieved in continuous-wave（CW） mode, with the slope efficiency being 42.1%. Chemical etching experiment revealed that the dominating imperfections in the studied Yb_（0.11）Gd_（0.89） COB crystal were dislocations and sub-grain boundaries. The existence of crystal defects could cause light scattering, and degrade laser output efficiency. The influence of crystal defects on laser properties was discussed.展开更多
The crystal structural parameters of Nd ^3＋-doped rare earth orthotantalate Gd x Lu 1 x TaO 4（x = 0.85） are determined by applying the Rietveld refinement to its X-ray diffraction,and its emission and excitation sp...The crystal structural parameters of Nd ^3＋-doped rare earth orthotantalate Gd x Lu 1 x TaO 4（x = 0.85） are determined by applying the Rietveld refinement to its X-ray diffraction,and its emission and excitation spectra at 77 K are analysed.The relativistic model of ab initio self-consistent DV-Xα method,which is applied to the cluster NdO 8 in Gd x Lu 1 x TaO 4,and the effective Hamiltonian model are used to investigate its spin-orbit and crystal-field parameters.The free-ions and crystal-field parameters are fitted to the experimental energy levels at 77 K with a root-mean-square deviation of 14.92 cm 1.According to the crystal-field calculations,96 levels of Nd ^3＋ are assigned.Finally,the fitting results of free-ions and crystal-field parameters are compared with those already reported for Nd ^3＋：YAlO 3.The results indicate that the free-ion parameters are similar to those of the Nd3＋ in Gdx Lu1-x TaO4 and YAlO 3 hosts,and the crystal-field interaction of Nd^3＋ in Gdx Lu1-x TaO4 is stronger than that in YAlO 3.展开更多
We observed the linear-to-zigzag structural phase transition of a ^40Ca^＋ crystal in a homemade linear Paul trap. The values of the total temperature of the ion crystals during the phase transition are derived using ...We observed the linear-to-zigzag structural phase transition of a ^40Ca^＋ crystal in a homemade linear Paul trap. The values of the total temperature of the ion crystals during the phase transition are derived using the molecular-dynamics（MD） simulation method. A series of simulations revealed that the ratio of the radial to axial secular frequencies has a dependence on the total temperature that obeys different functional forms for linear and zigzag structures, and the transition point occurs where these functions intersect; thus, the critical value of the ratio of secular frequencies that drives the structure phase transition can be derived.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
The effect of different initial microstructures deftned by γ' precipitate morphology has been investigated at the creep/fatigue conditions of 900℃ and 500 MPa. The wave form of stress as a function of time for c...The effect of different initial microstructures deftned by γ' precipitate morphology has been investigated at the creep/fatigue conditions of 900℃ and 500 MPa. The wave form of stress as a function of time for cyclic load was of trapezoidal shape with a hold time of 10s at the upper stress level. The TEM was employed to examine the deformation process in strengthened γ' matrix in dependence of γ' precipitate morphology. The fracture lifetime and cycle number up to fracture were the criteria to evaluate the additional cyclic component efFect on the course of deformation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
A stable one-dimensional system in an orthorhombic α-V<sub>2</sub>O<sub>5</sub> nanowires monocrystalline structure was obtained by a solvothermal method from a polymorphic V<sub>2</s...A stable one-dimensional system in an orthorhombic α-V<sub>2</sub>O<sub>5</sub> nanowires monocrystalline structure was obtained by a solvothermal method from a polymorphic V<sub>2</sub>O<sub>5</sub> structure. The starting material was firstly submitted to acid hydrolysis in H<sub>2</sub>O<sub>2</sub> followed by a solvothermal treatment. The outcome of this procedure, a metastable phase of the one-dimensional system V<sub>10</sub>O<sub>24</sub>·12H<sub>2</sub>O/V<sub>3</sub>O<sub>7</sub>·H<sub>2</sub>O, was subsequently reoxidized by controlled heating in an open air system. The final product was an orange crystalline solid mainly formed by monocrystalline nanowires of α-V<sub>2</sub>O<sub>5</sub> having lengths of tens of micrometers and widths of about 75 nm with a preferential [200] growth direction. It was found that the pH value of the initial solution plays an important role in the formation of the crystalline phase in the final products. Characterization was performed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). This study offers an alternate route for the synthesis of vanadium oxides and related compounds.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
Isoflavones which mainly distributed in leguminous plants have plenty of health benefits.Isoflavone synthase(IFS)is a membrane-associated cytochrome P450 enzyme(CYP450)which carries out the unique aryl-ring migration ...Isoflavones which mainly distributed in leguminous plants have plenty of health benefits.Isoflavone synthase(IFS)is a membrane-associated cytochrome P450 enzyme(CYP450)which carries out the unique aryl-ring migration and hydroxylation.So far,few crystal structures of plant P450s have been obtained.We determined the crystal structure of IFS from Medicago truncatula at 1.9 by MAD method using a selenomethionine substituted crystal and conducted molecular docking and mutagenesis study.The structure of IFS complexed with imidazole exhibits the helix Iα-loop-helix Iβmotif which corresponds to helix I of other P 450s.Compared with structures of common P450s,IFS/imidazole structure contains an extra domain,i.e.,theγ-domain.The structure reveals a homodimer in which theγ-domain of one molecule interacts with theβ-domain of another.The plane of heme group makes an angle of approximately 40°with the helix Iα-loop-helix Iβmotif.Molecular docking combined with mutagenesis study suggested that Trp-128 and Asp-300 might play important roles in substrate binding and recognition.Phe-301,Ser-303 and Gly-305 from the helix Iα-loop-helix Iβmotif may play important roles in the aryl-ring migration.These novel structural features reveal insights into the unique reaction mechanism of IFS and provide a basis for engineering IFS in leguminous crops for health purpose.展开更多
基金Project supported by the National Natural Science Foundation of China (No. 20271025) and Natural Science Foundation of Shandong Province (No. 2005ZX09)
文摘A novel organotin complex [Ph3Sn（C2H5OH）（OCOC5H3NBr）SnPh3（OCOC5H3NBr）] has been synthesized by the reaction of 5-bromonicotinic acid with triphenyltin hydroxide in ethanol and characterized by elemental analysis, IR and ^1H NMR. The crystal structure was determined by X-ray single-crystal diffraction. The crystal belongs to the monoclinic system, space group P21/c with a = 15.564（2）, b = 24.975（4）, c = 12.2973（19）°A, β = 92.224（2）°, Z = 4, V = 4776.5（13）°A^3, Dc = 1.596 g/cm^3, μ（MoKα） = 2.765 mm^-1, F（000） = 2264, R = 0.0385 and wR = 0.0667. In the molecular structure of the title complex, the tin atoms are five-coordinated in a trigonal bipyramidal geometry.
基金This project was supported by the National Natural Science Foundation of China (No. 20462007) and Xinjiang Bureau of Education (No. XJEDU2004S06)
文摘The reaction of 4-（p-fluobenzoyl）-2,5-dihydro-3-methyl-1-phenyl pyrazol-5-one with thiosemicarbazide in MeOH followed by recrystallization in EtOH gave rise to yellowish lamellar crystals of 4（p-fluo-a-aminothiocarbonyl hydrazonobenzal）-2,5-dihydro-3-methyl- 1-phenyl pyrazol-5-one 1. It crystallizes in orthorhombic, space group Pbca with a = 18.445（4）, b = 11.987（2）, c = 19.249（4） °A,, V= 4256.1（18）°A^3, Z = 8, Mr = 415.49, Dc= 1.297 g/cm^3, T = 296（2） K, F（000） = 1744,μ（MoKα） = 0.186 cm^-1, R = 0.0521 and wR = 0.1211 for 1661 observed reflections with I 〉 2σ（I）. The compound was structurally characterized by elemental analyses, IR and ^1H NMR. The intermolecular hydrogen bonds are present and a two-dimensional framework is formed by two intermolecular hydrogen bonds in the （001） plane.
基金This project was financially supported by the Doctoral Start-up Foundation of Guangxi University.
文摘The compound NdAlSi was studied using X-ray powder diffraction technique and refined by the Rietveld method. The compound NdAlSi has tetragonal α-ThSiE-type structure, space group I41/amd （No. 141）, Z = 4, and the lattice parameters a = 0.41991（1） nm, c = 1.44916（3） nm. The Smith and Snyder figure of merit FN is F30= 103.1（36）. The R-factors of Rietveld refinement are Rp= 0.113 and Rwp= 0.148, respectively. The X-ray powder diffraction data is presented in this article.
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 Natural Science Foundation of Henan Province(122300410418,132200410404)
文摘Two new isostructure nickel（Ⅱ） coordination polymers, [Ni2（5-Me-ip）（1,2- Bie）（H2O）2]n （1） and [Ni2（5-Br-ip）（1,2-Bie）（H2O）2]n （2） （5-Me-H2ip = 5-methylisophthalic acid, 5-Br-H2ip = 5-mromoisophthalic acid, 1,2-Bie = 1,2-bis（imidazole）ethane）, have been synthesized and structurally characterized by single-crystal X-ray diffraction. The result shows that complexes 1 and 2 crystallize in orthorhombic system, space group Pna21 with a = 16.3602（13）, b = 10.1465（8）, c = 21.8803（17）A^°, V = 3632.1（5） A^°3, Z = 4, Dc = 1.525 g/cm3, F（000） = 1728, R = 0.0292 and wR = 0.0668 for 6646 observed reflections （I 〉 2σ（I）） for complex 1 and a = 16.409（3）, b = 10.1625（17）, c = 21.918（4）A^°, V = 3654.9（11） A^°3, Z = 4, Dc = 1.752 g/cm^3, F（000） = 1936, R = 0.0309 and wR = 0.0600 for 6809 observed reflections （I 〉 2σ（I）） for complex 2. They both feature zigzag 2D layer structures, which are further staked along the a-axis through π…π and hydrogen interactions to form 3D supramolecular structures.
基金supported by the National Natural Science Foundation of China(21501012 and 51203012)
文摘Two new Cd（Ⅱ） coordination polymers, [Cd（PT）（1,4-BDC）0.5]n （1） and [Cd（PT） （1,3-BDC）0.5]n （2） （HPT = 3-（pyridin-2-yl）-1,2,4-triazole, 1,4-H2BDC = 1,4-benzenedicarboxylic acid, 1,3-H2BDC = 1,3-benzenedicarboxylic acid）, have been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction as well as elemental analysis and IR. Complexes 1 and 2 are both three-dimensional coordination polymers with two-dimensional sheet structures bridged by the deprotonated carboxylate ligands. In 1, 1,4-BDC2- bridges the layered network to generate a quadrangular framework, and 2 owns a sexangular framework, which was caused by the different steric hindrance between 1,4-BDC^2- and 1,3-BDC^2-. Their thermal stabilities and photoluminescent properties have been also investigated.
基金Project supported by Natural Science Foundation of Shandong Province (ZR2011EMM010)the Innovation Foundation of Shandong University
文摘KTb（WO4）2（KTW） single crystal with dimensions up to 30 mm×30 mm 10 mm was grown by the top-seeded solution growth （TSSG） method for the first time. The crystal structure was refined at room temperature by using single crystal X-ray diffiaction data. Ab- sorption and fluorescence spectra were measured at room temperature. The fluorescence lifetime of KTb（WO4）2 was 114 μs. The specific heat of the KTh（WO4）2 crystal was also measured at room temperature.
基金Project supported by National Natural Science Foundation of China(11204148,11374170)Taishan Scholar Program of Shandong Province+2 种基金Open Project of State Key Laboratory of Rare Earth Resource Utilization(RERU2016015)the Applied Basic Research Programs for Youths of Qingdao(15-9-1-52-JCH)Qingdao Postdoctoral Application Research Project(2015127)
文摘A Yb_（0.11）Gd_（0.89）Ca_4O（BO_3）_3 crystal with new composition was grown by the Czochralski method. The crystal structure was measured and analyzed. The unit-cell parameters of the Yb_（0.11）Gd_（0.89）COB were calculated to be a=0.8089（7） nm, b=1.5987（6） nm, c=0.3545（8） nm, β=101.22o. The absorption and fluorescence spectra were measured. The maximum absorption cross-section of Yb_（0.11）Gd_（0.89） COB crystal was 0.79×10^（–20）cm^2, which occurred at 976 nm with Y polarization. The emission cross-section at 1027 nm was calculated to be 0.33×10^（–20） cm^2. The radiative lifetime trad was calculated to be 2.74 ms. The Stark energy-level diagram of Yb^（3＋）in the Yb_（0.11）Gd_（0.89）COB crystal field at room temperature was determined. The ground-state energy level ~2F_（7/2） splitting was calculated to be as large as 1004 cm^（–1） and the zero-line energy was 10246 cm^（–1）. A maximum output power of 9.35 W was achieved in continuous-wave（CW） mode, with the slope efficiency being 42.1%. Chemical etching experiment revealed that the dominating imperfections in the studied Yb_（0.11）Gd_（0.89） COB crystal were dislocations and sub-grain boundaries. The existence of crystal defects could cause light scattering, and degrade laser output efficiency. The influence of crystal defects on laser properties was discussed.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 90922003,51172236,and 50872135)the Knowledge Innovation Program of the Chinese Academy of Sciences (Grant No. YYYJ-1002)
文摘The crystal structural parameters of Nd ^3＋-doped rare earth orthotantalate Gd x Lu 1 x TaO 4（x = 0.85） are determined by applying the Rietveld refinement to its X-ray diffraction,and its emission and excitation spectra at 77 K are analysed.The relativistic model of ab initio self-consistent DV-Xα method,which is applied to the cluster NdO 8 in Gd x Lu 1 x TaO 4,and the effective Hamiltonian model are used to investigate its spin-orbit and crystal-field parameters.The free-ions and crystal-field parameters are fitted to the experimental energy levels at 77 K with a root-mean-square deviation of 14.92 cm 1.According to the crystal-field calculations,96 levels of Nd ^3＋ are assigned.Finally,the fitting results of free-ions and crystal-field parameters are compared with those already reported for Nd ^3＋：YAlO 3.The results indicate that the free-ion parameters are similar to those of the Nd3＋ in Gdx Lu1-x TaO4 and YAlO 3 hosts,and the crystal-field interaction of Nd^3＋ in Gdx Lu1-x TaO4 is stronger than that in YAlO 3.
基金Project supported by the National Basic Research Program of China(Grant Nos.2010CB832803 and 2012CB821301)the National Natural Science Foundation of China(Grant Nos.11004222 and 91121016)the Chinese Academy of Sciences
文摘We observed the linear-to-zigzag structural phase transition of a ^40Ca^＋ crystal in a homemade linear Paul trap. The values of the total temperature of the ion crystals during the phase transition are derived using the molecular-dynamics（MD） simulation method. A series of simulations revealed that the ratio of the radial to axial secular frequencies has a dependence on the total temperature that obeys different functional forms for linear and zigzag structures, and the transition point occurs where these functions intersect; thus, the critical value of the ratio of secular frequencies that drives the structure phase transition can be derived.
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.
文摘The effect of different initial microstructures deftned by γ' precipitate morphology has been investigated at the creep/fatigue conditions of 900℃ and 500 MPa. The wave form of stress as a function of time for cyclic load was of trapezoidal shape with a hold time of 10s at the upper stress level. The TEM was employed to examine the deformation process in strengthened γ' matrix in dependence of γ' precipitate morphology. The fracture lifetime and cycle number up to fracture were the criteria to evaluate the additional cyclic component efFect on the course of deformation
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A stable one-dimensional system in an orthorhombic α-V<sub>2</sub>O<sub>5</sub> nanowires monocrystalline structure was obtained by a solvothermal method from a polymorphic V<sub>2</sub>O<sub>5</sub> structure. The starting material was firstly submitted to acid hydrolysis in H<sub>2</sub>O<sub>2</sub> followed by a solvothermal treatment. The outcome of this procedure, a metastable phase of the one-dimensional system V<sub>10</sub>O<sub>24</sub>·12H<sub>2</sub>O/V<sub>3</sub>O<sub>7</sub>·H<sub>2</sub>O, was subsequently reoxidized by controlled heating in an open air system. The final product was an orange crystalline solid mainly formed by monocrystalline nanowires of α-V<sub>2</sub>O<sub>5</sub> having lengths of tens of micrometers and widths of about 75 nm with a preferential [200] growth direction. It was found that the pH value of the initial solution plays an important role in the formation of the crystalline phase in the final products. Characterization was performed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). This study offers an alternate route for the synthesis of vanadium oxides and related compounds.
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.
文摘Isoflavones which mainly distributed in leguminous plants have plenty of health benefits.Isoflavone synthase(IFS)is a membrane-associated cytochrome P450 enzyme(CYP450)which carries out the unique aryl-ring migration and hydroxylation.So far,few crystal structures of plant P450s have been obtained.We determined the crystal structure of IFS from Medicago truncatula at 1.9 by MAD method using a selenomethionine substituted crystal and conducted molecular docking and mutagenesis study.The structure of IFS complexed with imidazole exhibits the helix Iα-loop-helix Iβmotif which corresponds to helix I of other P 450s.Compared with structures of common P450s,IFS/imidazole structure contains an extra domain,i.e.,theγ-domain.The structure reveals a homodimer in which theγ-domain of one molecule interacts with theβ-domain of another.The plane of heme group makes an angle of approximately 40°with the helix Iα-loop-helix Iβmotif.Molecular docking combined with mutagenesis study suggested that Trp-128 and Asp-300 might play important roles in substrate binding and recognition.Phe-301,Ser-303 and Gly-305 from the helix Iα-loop-helix Iβmotif may play important roles in the aryl-ring migration.These novel structural features reveal insights into the unique reaction mechanism of IFS and provide a basis for engineering IFS in leguminous crops for health purpose.
