N-4-（bromobutanoyl）-N＇-（o-, m- and p-tolyl）thioureas 3a, 3b and 3c respectively, were synthesized by the reaction of 4-bromobutanoylisothiocyanate with p-, m- and o-toludine. The products were characterized by IR...N-4-（bromobutanoyl）-N＇-（o-, m- and p-tolyl）thioureas 3a, 3b and 3c respectively, were synthesized by the reaction of 4-bromobutanoylisothiocyanate with p-, m- and o-toludine. The products were characterized by IR, and NMR spectroscopic techniques. The two carbonoylthiourea isomers N-（4-bromobutanoyl）-N＇-（3-methylphenyl）thiourea （3b） and N-（4-bromobutanoyl）-N＇-（4- methylphenyl）thiourea （3c） were obtained in crystalline form by recrystallization from DMSO. X- ray crystallographic studies showed that both compounds 3b and 3c crystallize in triclinic system with space group ofPi. The molecules adopt trans-cis configuration with respect to the positions of 4-bromobutanoyl and tolyl groups respectively, against the thiono C=S bond across their C-N bonds The configuration is attributed by the intrahydrogen bond between the carbonyl oxygen and amide hydrogen atoms. Both crystal structures are stabilized by N-H…S intermolecular hydrogen bonds to form dimers and arranged along the b axis.展开更多
A new neutral ternary samarium complex Sm（Phen）HL3 in which Phen is 1,10-phenanthroline and HL is （1,3-bis（1,3-dimethyl-1H-pyrazol-4-yl）-1,3-propanedione） was synthesized. Molecular structure of this complex was...A new neutral ternary samarium complex Sm（Phen）HL3 in which Phen is 1,10-phenanthroline and HL is （1,3-bis（1,3-dimethyl-1H-pyrazol-4-yl）-1,3-propanedione） was synthesized. Molecular structure of this complex was determined by X-ray diffraction. Under UV-light this complex is demonstrated bright red luminescence （λmax=647 nm）, which was corresponding to the electric dipole 4G5/2→6H9/2 transition in Sm3＋ ion. UV-absorption, excitation and emission spectra of the title compound were investigated.展开更多
The polymorphism of nitrofurantoin (NF), 1), the cocrystals of NF:2,2’-bipyridyl = 2:1, 2) and NF: 1,10-phenanthroline = 1:1, 3) have been prepared and characterized. The crystal structure analyses show that there ar...The polymorphism of nitrofurantoin (NF), 1), the cocrystals of NF:2,2’-bipyridyl = 2:1, 2) and NF: 1,10-phenanthroline = 1:1, 3) have been prepared and characterized. The crystal structure analyses show that there are various weak forces among the molecules, such as C/N-H···O, N-H···N hydrogen bond interactions and π···π/lone pair stacking interactions, which play a key role in the assembly of supramolecular networks. A thorough analysis of Hirshfeld surfaces and fingerprint plots facilitates a comparison of intermolecular interactions in 1 - 3, which are crucial in building supramolecular architectures.展开更多
The rapid synthesis of 3-bromocarbarole-N-acetic acid was performed using microwave irradiation. Under the optimal conditions the yield was 85.6% . The crystal structure showed that the carboxylic groups form bifurcat...The rapid synthesis of 3-bromocarbarole-N-acetic acid was performed using microwave irradiation. Under the optimal conditions the yield was 85.6% . The crystal structure showed that the carboxylic groups form bifurcated hydrogen bonds and the hydroxyl oxygen atoms serve as proton donors and also acceptor. Each carboxylic group was involved in four hydrogen bonds. The package of crystal was dominated by links of these hydrogen bonds.展开更多
A novel mixed barium(II)/silver(I)/chromium(III) oxalate salt, Ba<sub>0.5</sub>Ag<sub>2</sub>[Cr(C<sub>2</sub>O<sub>4</sub>)<sub>3</sub>]·5H<sub>2...A novel mixed barium(II)/silver(I)/chromium(III) oxalate salt, Ba<sub>0.5</sub>Ag<sub>2</sub>[Cr(C<sub>2</sub>O<sub>4</sub>)<sub>3</sub>]·5H<sub>2</sub>O (1), with open architecture has been synthesized in water and characterized by elemental analysis, vibrational and electronic spectra, and single crystal X-ray structure determination. Compound 1 crystallizes in a monoclinic space group C2/c, with unit cell parameters a = 18.179(3), b = 14.743(2), c = 12.278(2)Å, β = 113.821(3), V = 3010.34(90) Å<sup>3</sup>, Z = 8. The structure is characterized by a network of anionic [Cr(C<sub>2</sub>O<sub>4</sub>)<sub>3</sub>]<sup>3-</sup> units connected through the O atoms of the oxalates to Ba<sup>2+</sup> and Ag<sup>+</sup> sites, forming a three-dimensional coordination polymer with one-dimensional isolated nanochannels parallel to the c axis, and encapsulating hydrogen-bonded vip water molecules. The bulk structure is consolidated by O–H···O bridgings within the nanochannels and by coulombic interactions.展开更多
In this paper, we report the ground state properties i.e. electron momentum density and X-ray structure factors of fcc-copper are presented. The Am241 Compton spectrometer, which uses 59.54 keV gamma-rays, has been us...In this paper, we report the ground state properties i.e. electron momentum density and X-ray structure factors of fcc-copper are presented. The Am241 Compton spectrometer, which uses 59.54 keV gamma-rays, has been used for the Compton profile measurement. To compare the experimental data, the Compton profiles within the framework of linear combination of atomic orbitals (LCAO) method using Hartree–Fock (HF), density functional (DF) and hybrid B3PW schemes embodied in the CRYSTAL06 code have been computed. Among the various theoretical calculations, it is found that the present experimental data is in very good agreement with the hybrid B3PW scheme. A real-space analysis of the experimental Compton profile shows the metal-like behavior of copper The structure factors for copper are computed using hybrid B3PW scheme and compared with available experimental and theoretical data.展开更多
The title compound N-4-methyl-1,2,3-thiadiazole-5-carbonyl-N＇-3,5-dichloro-4- （1,1,2,2- tetrafluoroethoxyl）phenyl urea （C13H8Cl2F4N4O3S, Mr = 447.19） has been synthesized from 4-methyl- 1,2,3-thiadiazole-5-carbon...The title compound N-4-methyl-1,2,3-thiadiazole-5-carbonyl-N＇-3,5-dichloro-4- （1,1,2,2- tetrafluoroethoxyl）phenyl urea （C13H8Cl2F4N4O3S, Mr = 447.19） has been synthesized from 4-methyl- 1,2,3-thiadiazole-5-carbonyl chloride as the starting material, and its structure was characterized by proton Nuclear Magnetic Resonance （1H NMR）, Infra Red Spectroscopy （IR）, high-resolution mass spectroscopy （HRMS）, and single-crystal X-ray diffraction. The crystal of the title compound belongs to triclinic, space group Pi with a = 6.0780（8）, b = 11.3760（14）, c = 12.1440（18） A, α = 96.887（7）, β = 91.027（12）, γ= 104.252（13）°, Z = 2, V= 806.98（19）A3, Dc = 1.840 g/cm3, μ= 0.601 mm-1, F（000） = 448, R = 0.0450 and wR = 0.0869. X-ray analysis indicates that the 1,2,3-thiadiazole ring is not coplanar with the phenyl ring, and the dihedral angle is 33.57°. Two intermolecular hydrogen bonds N（2）-H…O（1 ）, S（1 ）…H-C（11）, and three weak intermolecular interactions, C（11）…O（1）, N（1）…O（2） and S…O（1）, are observed. The bioassay results indicate that the title compound has good insecticidal activity against Culex pipiens pallens and good induction activity for tobacco against tobacco mosaic virus which is equal to that of TDL.展开更多
7-（Diethylamino）-3-（4-aminophenyl）coumarin has been synthesized in a new one-pot synthesis by a three-step process starting from 4-（diethylamino）salicylaldehyde and 4-nitrophenylacetonitrile. The product was obt...7-（Diethylamino）-3-（4-aminophenyl）coumarin has been synthesized in a new one-pot synthesis by a three-step process starting from 4-（diethylamino）salicylaldehyde and 4-nitrophenylacetonitrile. The product was obtained in a good yield with a high degree of purity and characterized by NMR, IR and HR-MS. The orange crystals of the title compound were grown from ethyl acetate solution. The solid state structure was established by X-ray crystallography analysis. The crystal belongs to the orthorombic system, space group Pccn with a = 11.1095（5）, b = 33.0187（15）, c = 17.2865（7） A, V= 6341.1（5） A3, C19H20N2O2, Mr = 308.37, ρcalc = 1.292 g·cm^-3, = 0.085 mm^-1, F（000） = 2624, the final R = 0.0480 and wR = 0.1265 （I〉 2σ（I））.展开更多
An “experimental” valence state of metal complexes is sometime different from the “formal” oxidation state, especially in the species having redox active ligands. This difference can be seen in biological system, ...An “experimental” valence state of metal complexes is sometime different from the “formal” oxidation state, especially in the species having redox active ligands. This difference can be seen in biological system, such as iron(IV)-porphyrin π-cation radical in some heme proteins and copper(II)-phenoxyl radical in galactose oxidase (GO). Although structural characterizations of these species by X-ray diffraction methods have been rare due to their stability, some artificial metal-phenoxyl radical complexes have been synthesized and successfully characterized by X-ray crystal structure. In this review, syntheses and X-ray crystal structures of the one-electron oxidized metal-phenolate complexes, metal- phenoxyl radical, and high-valent metal phenolate species are discussed.展开更多
Trifluoroacetic acid(TFA)catalyzed condensation reaction between tetraaminooxacalix[4]arene and N-alkylcarbazole-3,6-dicarbaldehyde in CH_(2)Cl2afforded a single product in 87%–89%yield.Well-defined yet undissolvable...Trifluoroacetic acid(TFA)catalyzed condensation reaction between tetraaminooxacalix[4]arene and N-alkylcarbazole-3,6-dicarbaldehyde in CH_(2)Cl2afforded a single product in 87%–89%yield.Well-defined yet undissolvable1H NMR spectra suggested formation of robust and discrete structures in solution.X-ray single crystal analysis further revealed a giant twisted double-layer chiral macrocycle in the solid state,which was formed from[4+8]condensation of the two reactants via 16 imine bonds.DFT calculations discovered that only the[4+8]twisted product is thermodynamically favorable,which accounts for its highly selective and efficient formation out of a library of many other combinations.展开更多
The title compound (C28H27NO5S3, Mr= 553. 69) was prepared bythe reaction of a-thiobenzoylthioformmorholine with diethyl acetylene dicarboxylate.The crystal is monoclinic, space group P21/n with a= 9. 160(3), b= 17. 7...The title compound (C28H27NO5S3, Mr= 553. 69) was prepared bythe reaction of a-thiobenzoylthioformmorholine with diethyl acetylene dicarboxylate.The crystal is monoclinic, space group P21/n with a= 9. 160(3), b= 17. 726(3), c=16. 602(3) A ; β= 100. 375(13)°; V=2651. 4(10) A3, Z=4, Dc= 1. 387 g/cm3, μ(MoKa) =0. 319 mm-1, F(000) =1160, R=0. 0428, wR(F2) =0. 0910 for 2438 observed reflections (I>2(I)). X-ray analysis reveals that interatomic distances for C(5)-C(6), C(13)-C(14) and C(21)-C(22) are 1. 331(4), 1. 351(4), 1. 344(4)A respectively, which show that they are normal C=C double bonds. All S-C bondlengths are similar to typical S-C single bonds (1. 75 - 1. 78 A ). The five-membered ring A (C(5) -C(6) -S(2)-C(13) -S(1) ) (Fig. 1) and six-membered ringB (C(14) -C(15) -C(20) -C(21)-C(22)-S(3) ) (Fig. 1) adopt the flat twist conformation. Furthermore, the morpholine ring adopts chair conformtion.展开更多
The title compound (C28H27NO5S3, Mr= 553. 69) was prepared bythe reaction of a-thiobenzoylthioformmorholine with diethyl acetylene dicarboxylate.The crystal is monoclinic, space group P21/n with a= 9. 160(3), b= 17. 7...The title compound (C28H27NO5S3, Mr= 553. 69) was prepared bythe reaction of a-thiobenzoylthioformmorholine with diethyl acetylene dicarboxylate.The crystal is monoclinic, space group P21/n with a= 9. 160(3), b= 17. 726(3), c=16. 602(3) A ; β= 100. 375(13)°; V=2651. 4(10) A3, Z=4, Dc= 1. 387 g/cm3, μ(MoKa) =0. 319 mm-1, F(000) =1160, R=0. 0428, wR(F2) =0. 0910 for 2438 observed reflections (I】2(I)). X-ray analysis reveals that interatomic distances for C(5)-C(6), C(13)-C(14) and C(21)-C(22) are 1. 331(4), 1. 351(4), 1. 344(4)A respectively, which show that they are normal C=C double bonds. All S-C bondlengths are similar to typical S-C single bonds (1. 75 - 1. 78 A ). The five-membered ring A (C(5) -C(6) -S(2)-C(13) -S(1) ) (Fig. 1) and six-membered ringB (C(14) -C(15) -C(20) -C(21)-C(22)-S(3) ) (Fig. 1) adopt the flat twist conformation. Furthermore, the morpholine ring adopts chair conformtion.展开更多
Van der Waals(vdW)heterostructures have attracted much attention due to their distinctive optical,electrical,and thermal properties,demonstrating promising potential in areas such as photocatalysis,ultrafast photonics...Van der Waals(vdW)heterostructures have attracted much attention due to their distinctive optical,electrical,and thermal properties,demonstrating promising potential in areas such as photocatalysis,ultrafast photonics,and free electron radiation devices.Particularly,they are promising platforms for studying thermionic emission.It is illustrated that using vdW heterostructure-based thermionic emission can enhance heat transfer in vacuum devices.As a proof of concept,the approach is demonstrated to offer a promising solution for the long-standing overheating issue in X-ray tubes.Specifically,it is shown that the saturated target temperature of a 2000 W X-ray tube can be reduced from around 1200℃ to 490℃.Additionally,it is also demonstrated that by reducing the height of the Schottky barrier formed in the vdW heterostructures,the thermionic cooling performance can be enhanced.The findings pave the way for the development of high-power X-ray tubes.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
The interaction of sodium aurothiomalate with the apo form of human serum transferrin(hTF)was studied by X-ray crystallography.The protein binds gold ions close to the side chains of His25,Asp63 and His249,His207 and ...The interaction of sodium aurothiomalate with the apo form of human serum transferrin(hTF)was studied by X-ray crystallography.The protein binds gold ions close to the side chains of His25,Asp63 and His249,His207 and Tyr238,and His273,His289,His300,His473,His585,His598,His606,and His642;the thiomalate ligand is released.Notably,the N-and C-lobes of one of the two hTF molecules in the asymmetric unit of the Au-hTF adduct crystals exhibit conformations that are slightly different from those observed in the“fully opened”apo-hTF,with the N-lobe that is intermediate between the“partially opened”form observed in the structure of hTF with Bi^(3+) and the“fully opened”form of apo-hTF.Thus,our data provide relevant information about the binding of gold centers to hTF and on a unique hTF structure along the apo-hTF/holo-hTF transition pathway.展开更多
In this study,an inverse design framework was established to find lightweight honeycomb structures(HCSs)with high impact resistance.The hybrid HCS,composed of re-entrant(RE)and elliptical annular re-entrant(EARE)honey...In this study,an inverse design framework was established to find lightweight honeycomb structures(HCSs)with high impact resistance.The hybrid HCS,composed of re-entrant(RE)and elliptical annular re-entrant(EARE)honeycomb cells,was created by constructing arrangement matrices to achieve structural lightweight.The machine learning(ML)framework consisted of a neural network(NN)forward regression model for predicting impact resistance and a multi-objective optimization algorithm for generating high-performance designs.The surrogate of the local design space was initially realized by establishing the NN in the small sample dataset,and the active learning strategy was used to continuously extended the local optimal design until the model converged in the global space.The results indicated that the active learning strategy significantly improved the inference capability of the NN model in unknown design domains.By guiding the iteration direction of the optimization algorithm,lightweight designs with high impact resistance were identified.The energy absorption capacity of the optimal design reached 94.98%of the EARE honeycomb,while the initial peak stress and mass decreased by 28.85%and 19.91%,respectively.Furthermore,Shapley Additive Explanations(SHAP)for global explanation of the NN indicated a strong correlation between the arrangement mode of HCS and its impact resistance.By reducing the stiffness of the cells at the top boundary of the structure,the initial impact damage sustained by the structure can be significantly improved.Overall,this study proposed a general lightweight design method for array structures under impact loads,which is beneficial for the widespread application of honeycomb-based protective structures.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
In this study,a novel polysaccharide GPA-G 2-H was derived from ginseng.Furthermore,the coherent study of its structural characteristics,fermented characteristics in vitro,as well as antioxidant mechanism of fermented...In this study,a novel polysaccharide GPA-G 2-H was derived from ginseng.Furthermore,the coherent study of its structural characteristics,fermented characteristics in vitro,as well as antioxidant mechanism of fermented product FGPA-G 2-H on Aβ25-35-induced PC 12 cells were explored.The structure of GPA-G 2-H was determined by means of zeta potential analysis,FTIR,HPLC,XRD,GC-MS and NMR.The backbone of GPA-G 2-H was mainly composed of→4)-α-D-Glcp-(1→with branches substituted at O-3.Notably,GPA-G 2-H was degraded by intestinal microbiota in vitro with total sugar content and pH value decreasing,and short-chain fatty acids(SCFAs)increasing.Moreover,GPA-G 2-H significantly promoted the proliferation of Lactobacillus,Muribaculaceae and Weissella,thereby making positive alterations in intestinal microbiota composition.Additionally,FGPA-G 2-H activated the Nrf 2/HO-1 signaling pathway,enhanced HO-1,NQO 1,SOD and GSH-Px,while inhabited Keap 1,MDA and LDH,which alleviated Aβ-induced oxidative stress in PC 12 cells.These provide a solid theoretical basis for the further development of ginseng polysaccharides as functional food and antioxidant drugs.展开更多
Two Co(Ⅱ)and Ni(Ⅱ)complexes were synthesized by synergistic coordination of 3,3-diphenylpropionic acid(HDPA)and 2,2′-bipyridylamine(PAm).The structures of complexes[Co(DPA)_(2)(PAm)]·2H_(2)O(1)and[Ni(DPA)_(2)(...Two Co(Ⅱ)and Ni(Ⅱ)complexes were synthesized by synergistic coordination of 3,3-diphenylpropionic acid(HDPA)and 2,2′-bipyridylamine(PAm).The structures of complexes[Co(DPA)_(2)(PAm)]·2H_(2)O(1)and[Ni(DPA)_(2)(PAm)]·2H_(2)O(2)were determined by single-crystal X-ray diffraction,IR spectroscopy,and powder X-ray diffraction.Hirshfeld surface analysis provided quantitative insights into the intermolecular interactions within the complexes,while molecular docking studies elucidated their binding modes and affinities toward urease.Furthermore,the biological activities of both complexes were systematically evaluated through a range of assays,including DNA binding,urease inhibition,antibacterial activity,and in vitro cytotoxicity against cancer cells.Both complexes exhibited binding affinity for DNA and displayed notable urease inhibitory activity.Under in vitro conditions,both complexes showed appreciable cytotoxicity toward HepG2 cells with efficacy comparable to clinically used platinumbased anticancer agents.CCDC:2479943,1;2479944,2.展开更多
Conformal truss-like lattice structures face significant manufacturability challenges in additive manufac-turing due to overhang angle limitations.To address this problem,we propose a novel angle-constrained optimizat...Conformal truss-like lattice structures face significant manufacturability challenges in additive manufac-turing due to overhang angle limitations.To address this problem,we propose a novel angle-constrained optimization method grounded in the global adjustment of nodal coordinates.First,a build direction is selected to minimize the number of violating struts.Then,an angular-constraint matrix is assembled from strut direction vectors,and analytical sensitivities with respect to nodal coordinates are derived to enable efficient constrained optimization under nonlinear angular inequality constraints.Numerical studies on two complex curved-surface lattices demonstrate that all overhang violations are eliminated while only minor changes are induced in global stiffness and strength.In particular,the maximum displacement of an ergonomic insole varies by only 2.87%after optimization.The results confirm the method’s versatility and engineering robustness,providing a practical approach for additive manufacturing-oriented lattice structure design.展开更多
基金the Ministry of Higher Education of Malaysia and Universiti Kebangsaan Malaysia for the research grant DIP-2014-016 and FRGS/1/2013/ST01/UKM/03/4the Ministry of Higher Education of Libya for the scholarship
文摘N-4-（bromobutanoyl）-N＇-（o-, m- and p-tolyl）thioureas 3a, 3b and 3c respectively, were synthesized by the reaction of 4-bromobutanoylisothiocyanate with p-, m- and o-toludine. The products were characterized by IR, and NMR spectroscopic techniques. The two carbonoylthiourea isomers N-（4-bromobutanoyl）-N＇-（3-methylphenyl）thiourea （3b） and N-（4-bromobutanoyl）-N＇-（4- methylphenyl）thiourea （3c） were obtained in crystalline form by recrystallization from DMSO. X- ray crystallographic studies showed that both compounds 3b and 3c crystallize in triclinic system with space group ofPi. The molecules adopt trans-cis configuration with respect to the positions of 4-bromobutanoyl and tolyl groups respectively, against the thiono C=S bond across their C-N bonds The configuration is attributed by the intrahydrogen bond between the carbonyl oxygen and amide hydrogen atoms. Both crystal structures are stabilized by N-H…S intermolecular hydrogen bonds to form dimers and arranged along the b axis.
文摘A new neutral ternary samarium complex Sm（Phen）HL3 in which Phen is 1,10-phenanthroline and HL is （1,3-bis（1,3-dimethyl-1H-pyrazol-4-yl）-1,3-propanedione） was synthesized. Molecular structure of this complex was determined by X-ray diffraction. Under UV-light this complex is demonstrated bright red luminescence （λmax=647 nm）, which was corresponding to the electric dipole 4G5/2→6H9/2 transition in Sm3＋ ion. UV-absorption, excitation and emission spectra of the title compound were investigated.
文摘The polymorphism of nitrofurantoin (NF), 1), the cocrystals of NF:2,2’-bipyridyl = 2:1, 2) and NF: 1,10-phenanthroline = 1:1, 3) have been prepared and characterized. The crystal structure analyses show that there are various weak forces among the molecules, such as C/N-H···O, N-H···N hydrogen bond interactions and π···π/lone pair stacking interactions, which play a key role in the assembly of supramolecular networks. A thorough analysis of Hirshfeld surfaces and fingerprint plots facilitates a comparison of intermolecular interactions in 1 - 3, which are crucial in building supramolecular architectures.
文摘The rapid synthesis of 3-bromocarbarole-N-acetic acid was performed using microwave irradiation. Under the optimal conditions the yield was 85.6% . The crystal structure showed that the carboxylic groups form bifurcated hydrogen bonds and the hydroxyl oxygen atoms serve as proton donors and also acceptor. Each carboxylic group was involved in four hydrogen bonds. The package of crystal was dominated by links of these hydrogen bonds.
文摘A novel mixed barium(II)/silver(I)/chromium(III) oxalate salt, Ba<sub>0.5</sub>Ag<sub>2</sub>[Cr(C<sub>2</sub>O<sub>4</sub>)<sub>3</sub>]·5H<sub>2</sub>O (1), with open architecture has been synthesized in water and characterized by elemental analysis, vibrational and electronic spectra, and single crystal X-ray structure determination. Compound 1 crystallizes in a monoclinic space group C2/c, with unit cell parameters a = 18.179(3), b = 14.743(2), c = 12.278(2)Å, β = 113.821(3), V = 3010.34(90) Å<sup>3</sup>, Z = 8. The structure is characterized by a network of anionic [Cr(C<sub>2</sub>O<sub>4</sub>)<sub>3</sub>]<sup>3-</sup> units connected through the O atoms of the oxalates to Ba<sup>2+</sup> and Ag<sup>+</sup> sites, forming a three-dimensional coordination polymer with one-dimensional isolated nanochannels parallel to the c axis, and encapsulating hydrogen-bonded vip water molecules. The bulk structure is consolidated by O–H···O bridgings within the nanochannels and by coulombic interactions.
文摘In this paper, we report the ground state properties i.e. electron momentum density and X-ray structure factors of fcc-copper are presented. The Am241 Compton spectrometer, which uses 59.54 keV gamma-rays, has been used for the Compton profile measurement. To compare the experimental data, the Compton profiles within the framework of linear combination of atomic orbitals (LCAO) method using Hartree–Fock (HF), density functional (DF) and hybrid B3PW schemes embodied in the CRYSTAL06 code have been computed. Among the various theoretical calculations, it is found that the present experimental data is in very good agreement with the hybrid B3PW scheme. A real-space analysis of the experimental Compton profile shows the metal-like behavior of copper The structure factors for copper are computed using hybrid B3PW scheme and compared with available experimental and theoretical data.
基金funded in part by grants from the National Natural Science Foundation of China (20872071)the Natural Science Foundation of Tianjin (10JCZDJC17500)+3 种基金the National Key Project for Basic Research (2010CB126105)the National Key Technology Research and Development Program (2011BAE06B02)the Foundation of Achievements Transformation and Spreading of Tianjin Agricultural Science and Technology(201002250)Tianjin Key Technology Research and Development Program (11ZCGYNC00100)
文摘The title compound N-4-methyl-1,2,3-thiadiazole-5-carbonyl-N＇-3,5-dichloro-4- （1,1,2,2- tetrafluoroethoxyl）phenyl urea （C13H8Cl2F4N4O3S, Mr = 447.19） has been synthesized from 4-methyl- 1,2,3-thiadiazole-5-carbonyl chloride as the starting material, and its structure was characterized by proton Nuclear Magnetic Resonance （1H NMR）, Infra Red Spectroscopy （IR）, high-resolution mass spectroscopy （HRMS）, and single-crystal X-ray diffraction. The crystal of the title compound belongs to triclinic, space group Pi with a = 6.0780（8）, b = 11.3760（14）, c = 12.1440（18） A, α = 96.887（7）, β = 91.027（12）, γ= 104.252（13）°, Z = 2, V= 806.98（19）A3, Dc = 1.840 g/cm3, μ= 0.601 mm-1, F（000） = 448, R = 0.0450 and wR = 0.0869. X-ray analysis indicates that the 1,2,3-thiadiazole ring is not coplanar with the phenyl ring, and the dihedral angle is 33.57°. Two intermolecular hydrogen bonds N（2）-H…O（1 ）, S（1 ）…H-C（11）, and three weak intermolecular interactions, C（11）…O（1）, N（1）…O（2） and S…O（1）, are observed. The bioassay results indicate that the title compound has good insecticidal activity against Culex pipiens pallens and good induction activity for tobacco against tobacco mosaic virus which is equal to that of TDL.
基金The"Groupement Franco-Ukrainien en Chimie Moléculaire"(GDRI)and the Embassy of France in Kyiv are gratefully acknowledged for financial support
文摘7-（Diethylamino）-3-（4-aminophenyl）coumarin has been synthesized in a new one-pot synthesis by a three-step process starting from 4-（diethylamino）salicylaldehyde and 4-nitrophenylacetonitrile. The product was obtained in a good yield with a high degree of purity and characterized by NMR, IR and HR-MS. The orange crystals of the title compound were grown from ethyl acetate solution. The solid state structure was established by X-ray crystallography analysis. The crystal belongs to the orthorombic system, space group Pccn with a = 11.1095（5）, b = 33.0187（15）, c = 17.2865（7） A, V= 6341.1（5） A3, C19H20N2O2, Mr = 308.37, ρcalc = 1.292 g·cm^-3, = 0.085 mm^-1, F（000） = 2624, the final R = 0.0480 and wR = 0.1265 （I〉 2σ（I））.
文摘An “experimental” valence state of metal complexes is sometime different from the “formal” oxidation state, especially in the species having redox active ligands. This difference can be seen in biological system, such as iron(IV)-porphyrin π-cation radical in some heme proteins and copper(II)-phenoxyl radical in galactose oxidase (GO). Although structural characterizations of these species by X-ray diffraction methods have been rare due to their stability, some artificial metal-phenoxyl radical complexes have been synthesized and successfully characterized by X-ray crystal structure. In this review, syntheses and X-ray crystal structures of the one-electron oxidized metal-phenolate complexes, metal- phenoxyl radical, and high-valent metal phenolate species are discussed.
基金supported by the National Natural Science Foundation of China(Nos.21971223 and 21772178)。
文摘Trifluoroacetic acid(TFA)catalyzed condensation reaction between tetraaminooxacalix[4]arene and N-alkylcarbazole-3,6-dicarbaldehyde in CH_(2)Cl2afforded a single product in 87%–89%yield.Well-defined yet undissolvable1H NMR spectra suggested formation of robust and discrete structures in solution.X-ray single crystal analysis further revealed a giant twisted double-layer chiral macrocycle in the solid state,which was formed from[4+8]condensation of the two reactants via 16 imine bonds.DFT calculations discovered that only the[4+8]twisted product is thermodynamically favorable,which accounts for its highly selective and efficient formation out of a library of many other combinations.
文摘The title compound (C28H27NO5S3, Mr= 553. 69) was prepared bythe reaction of a-thiobenzoylthioformmorholine with diethyl acetylene dicarboxylate.The crystal is monoclinic, space group P21/n with a= 9. 160(3), b= 17. 726(3), c=16. 602(3) A ; β= 100. 375(13)°; V=2651. 4(10) A3, Z=4, Dc= 1. 387 g/cm3, μ(MoKa) =0. 319 mm-1, F(000) =1160, R=0. 0428, wR(F2) =0. 0910 for 2438 observed reflections (I>2(I)). X-ray analysis reveals that interatomic distances for C(5)-C(6), C(13)-C(14) and C(21)-C(22) are 1. 331(4), 1. 351(4), 1. 344(4)A respectively, which show that they are normal C=C double bonds. All S-C bondlengths are similar to typical S-C single bonds (1. 75 - 1. 78 A ). The five-membered ring A (C(5) -C(6) -S(2)-C(13) -S(1) ) (Fig. 1) and six-membered ringB (C(14) -C(15) -C(20) -C(21)-C(22)-S(3) ) (Fig. 1) adopt the flat twist conformation. Furthermore, the morpholine ring adopts chair conformtion.
文摘The title compound (C28H27NO5S3, Mr= 553. 69) was prepared bythe reaction of a-thiobenzoylthioformmorholine with diethyl acetylene dicarboxylate.The crystal is monoclinic, space group P21/n with a= 9. 160(3), b= 17. 726(3), c=16. 602(3) A ; β= 100. 375(13)°; V=2651. 4(10) A3, Z=4, Dc= 1. 387 g/cm3, μ(MoKa) =0. 319 mm-1, F(000) =1160, R=0. 0428, wR(F2) =0. 0910 for 2438 observed reflections (I】2(I)). X-ray analysis reveals that interatomic distances for C(5)-C(6), C(13)-C(14) and C(21)-C(22) are 1. 331(4), 1. 351(4), 1. 344(4)A respectively, which show that they are normal C=C double bonds. All S-C bondlengths are similar to typical S-C single bonds (1. 75 - 1. 78 A ). The five-membered ring A (C(5) -C(6) -S(2)-C(13) -S(1) ) (Fig. 1) and six-membered ringB (C(14) -C(15) -C(20) -C(21)-C(22)-S(3) ) (Fig. 1) adopt the flat twist conformation. Furthermore, the morpholine ring adopts chair conformtion.
基金supported by National Natural Science Foundation of China(61921002 and 92163204)。
文摘Van der Waals(vdW)heterostructures have attracted much attention due to their distinctive optical,electrical,and thermal properties,demonstrating promising potential in areas such as photocatalysis,ultrafast photonics,and free electron radiation devices.Particularly,they are promising platforms for studying thermionic emission.It is illustrated that using vdW heterostructure-based thermionic emission can enhance heat transfer in vacuum devices.As a proof of concept,the approach is demonstrated to offer a promising solution for the long-standing overheating issue in X-ray tubes.Specifically,it is shown that the saturated target temperature of a 2000 W X-ray tube can be reduced from around 1200℃ to 490℃.Additionally,it is also demonstrated that by reducing the height of the Schottky barrier formed in the vdW heterostructures,the thermionic cooling performance can be enhanced.The findings pave the way for the development of high-power X-ray tubes.
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supported with a research fellowship by#NEXTGENERATIONEU(NGEU)the Ministry of University and Research(MUR),the National Recovery and Resilience Plan(NRRP),project MNESYS(PE0000006)-A Multiscale integrated approach to the study of the nervous system in health and disease(DN.155311.10.2022)MIUR PRIN 2022-Cod.2022JMFC3X,“Protein Metalation by Anticancer Metal-based Drugs”for financial support.
文摘The interaction of sodium aurothiomalate with the apo form of human serum transferrin(hTF)was studied by X-ray crystallography.The protein binds gold ions close to the side chains of His25,Asp63 and His249,His207 and Tyr238,and His273,His289,His300,His473,His585,His598,His606,and His642;the thiomalate ligand is released.Notably,the N-and C-lobes of one of the two hTF molecules in the asymmetric unit of the Au-hTF adduct crystals exhibit conformations that are slightly different from those observed in the“fully opened”apo-hTF,with the N-lobe that is intermediate between the“partially opened”form observed in the structure of hTF with Bi^(3+) and the“fully opened”form of apo-hTF.Thus,our data provide relevant information about the binding of gold centers to hTF and on a unique hTF structure along the apo-hTF/holo-hTF transition pathway.
基金the financial supports from National Key R&D Program for Young Scientists of China(Grant No.2022YFC3080900)National Natural Science Foundation of China(Grant No.52374181)+1 种基金BIT Research and Innovation Promoting Project(Grant No.2024YCXZ017)supported by Science and Technology Innovation Program of Beijing institute of technology under Grant No.2022CX01025。
文摘In this study,an inverse design framework was established to find lightweight honeycomb structures(HCSs)with high impact resistance.The hybrid HCS,composed of re-entrant(RE)and elliptical annular re-entrant(EARE)honeycomb cells,was created by constructing arrangement matrices to achieve structural lightweight.The machine learning(ML)framework consisted of a neural network(NN)forward regression model for predicting impact resistance and a multi-objective optimization algorithm for generating high-performance designs.The surrogate of the local design space was initially realized by establishing the NN in the small sample dataset,and the active learning strategy was used to continuously extended the local optimal design until the model converged in the global space.The results indicated that the active learning strategy significantly improved the inference capability of the NN model in unknown design domains.By guiding the iteration direction of the optimization algorithm,lightweight designs with high impact resistance were identified.The energy absorption capacity of the optimal design reached 94.98%of the EARE honeycomb,while the initial peak stress and mass decreased by 28.85%and 19.91%,respectively.Furthermore,Shapley Additive Explanations(SHAP)for global explanation of the NN indicated a strong correlation between the arrangement mode of HCS and its impact resistance.By reducing the stiffness of the cells at the top boundary of the structure,the initial impact damage sustained by the structure can be significantly improved.Overall,this study proposed a general lightweight design method for array structures under impact loads,which is beneficial for the widespread application of honeycomb-based protective structures.
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 National Key Research and Development Program of Traditional Chinese Medicine Modernization Project,China(No.2023YFC3504000)the Science and Technology Development Project of Jilin Province,China(No.20240404043ZP)the Science and Technology Innovation Cooperation Project of Changchun Science and Technology Bureau and Chinese Academy of Sciences,China(No.23SH14)。
文摘In this study,a novel polysaccharide GPA-G 2-H was derived from ginseng.Furthermore,the coherent study of its structural characteristics,fermented characteristics in vitro,as well as antioxidant mechanism of fermented product FGPA-G 2-H on Aβ25-35-induced PC 12 cells were explored.The structure of GPA-G 2-H was determined by means of zeta potential analysis,FTIR,HPLC,XRD,GC-MS and NMR.The backbone of GPA-G 2-H was mainly composed of→4)-α-D-Glcp-(1→with branches substituted at O-3.Notably,GPA-G 2-H was degraded by intestinal microbiota in vitro with total sugar content and pH value decreasing,and short-chain fatty acids(SCFAs)increasing.Moreover,GPA-G 2-H significantly promoted the proliferation of Lactobacillus,Muribaculaceae and Weissella,thereby making positive alterations in intestinal microbiota composition.Additionally,FGPA-G 2-H activated the Nrf 2/HO-1 signaling pathway,enhanced HO-1,NQO 1,SOD and GSH-Px,while inhabited Keap 1,MDA and LDH,which alleviated Aβ-induced oxidative stress in PC 12 cells.These provide a solid theoretical basis for the further development of ginseng polysaccharides as functional food and antioxidant drugs.
文摘Two Co(Ⅱ)and Ni(Ⅱ)complexes were synthesized by synergistic coordination of 3,3-diphenylpropionic acid(HDPA)and 2,2′-bipyridylamine(PAm).The structures of complexes[Co(DPA)_(2)(PAm)]·2H_(2)O(1)and[Ni(DPA)_(2)(PAm)]·2H_(2)O(2)were determined by single-crystal X-ray diffraction,IR spectroscopy,and powder X-ray diffraction.Hirshfeld surface analysis provided quantitative insights into the intermolecular interactions within the complexes,while molecular docking studies elucidated their binding modes and affinities toward urease.Furthermore,the biological activities of both complexes were systematically evaluated through a range of assays,including DNA binding,urease inhibition,antibacterial activity,and in vitro cytotoxicity against cancer cells.Both complexes exhibited binding affinity for DNA and displayed notable urease inhibitory activity.Under in vitro conditions,both complexes showed appreciable cytotoxicity toward HepG2 cells with efficacy comparable to clinically used platinumbased anticancer agents.CCDC:2479943,1;2479944,2.
基金supported by the National Natural Science Foundation of China(Grant Nos.12432005 and 12472116)the Fundamental Research Funds for the Central Universities(DUTZD25240).
文摘Conformal truss-like lattice structures face significant manufacturability challenges in additive manufac-turing due to overhang angle limitations.To address this problem,we propose a novel angle-constrained optimization method grounded in the global adjustment of nodal coordinates.First,a build direction is selected to minimize the number of violating struts.Then,an angular-constraint matrix is assembled from strut direction vectors,and analytical sensitivities with respect to nodal coordinates are derived to enable efficient constrained optimization under nonlinear angular inequality constraints.Numerical studies on two complex curved-surface lattices demonstrate that all overhang violations are eliminated while only minor changes are induced in global stiffness and strength.In particular,the maximum displacement of an ergonomic insole varies by only 2.87%after optimization.The results confirm the method’s versatility and engineering robustness,providing a practical approach for additive manufacturing-oriented lattice structure design.
