1 Introduction Recently,the increasing demand for advanced telecommunication systems has spurred extensive research into bandpass filters(BPFs),with particular emphasis on miniaturization,reduction of insertion loss(I...1 Introduction Recently,the increasing demand for advanced telecommunication systems has spurred extensive research into bandpass filters(BPFs),with particular emphasis on miniaturization,reduction of insertion loss(IL),and enhancement of upper stopband rejection(Huang et al.,2021;Snyder et al.,2021;Lin et al.,2023;Zeng et al.,2023).展开更多
Mixed symmetry states are studied in the framework of the neutron-proton interacting boson model. It is found that some of the mixed symmetry states with moderate high spins change very fast with respect to the Majora...Mixed symmetry states are studied in the framework of the neutron-proton interacting boson model. It is found that some of the mixed symmetry states with moderate high spins change very fast with respect to the Majorana interaction. Under certain conditions, they become the yrast state or yrare state. These states are difficult to decay and become very stable. This study suggests that a possible new mode of isomers may exist due to the special nature in their proton and neutron degrees of freedom.展开更多
We present here a series of perylene diimide(PDI)based isomeric conjugated polymers for the application as efficient electron acceptors in all-polymer solar cells(all-PSCs).By copolymerizing PDI monomers with 1,4-diet...We present here a series of perylene diimide(PDI)based isomeric conjugated polymers for the application as efficient electron acceptors in all-polymer solar cells(all-PSCs).By copolymerizing PDI monomers with 1,4-diethynylbenzene(para-linkage)and 1,3-diethynylbenzene(meta-linkage),isomeric PDI based conjugated polymers with parallel and non-parallel PDI units inside backbones were obtained.It was found that para-linked conjugated polymer(PA)showed better solubility,strongerπ-πstacking,more favorable blend morphology,and better photovoltaic performance than those of meta-linked conjugated polymers(PM)did.Device based on PTB7-Th:PA(PTB7-Th:poly{4,8-bis[5-(2-ethylhexyl)-thiophen-2-yl]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl-alt-3-fluoro-2-[(2-ethylhexyl)-carbonyl]thieno[3,4-b]thiophene-4,6-diyl})showed significantly enhanced photovoltaic performance than that of PTB7-Th:MA(3.29%versus 0.92%).Moreover,the photovoltaic performance of these polymeric acceptors could be further improved via a terpolymeric strategy.By copolymerizing a small amount of meta-linkages into PA,the optimized terpolymeric acceptors enabled to enhance photovoltaic performance with improved the short-circuit current density(Jsc)and fill factor(FF),resulting in an improved power conversion efficiency(PCE)of 4.03%.展开更多
Two isomeric metal-organic frameworks(MOFs) with 2-dimensional(2D) and 3-dimensional(3D) topologies both comprised of Cu(Ⅱ) and OTf(OTf = trifluoromethanesulfonate) ions were synthesized and characterized.The CO_2,CH...Two isomeric metal-organic frameworks(MOFs) with 2-dimensional(2D) and 3-dimensional(3D) topologies both comprised of Cu(Ⅱ) and OTf(OTf = trifluoromethanesulfonate) ions were synthesized and characterized.The CO_2,CH_4 and N_2 adsorption properties of the two isomeric MOFs were investigated from 263 K to 298 K at0.1 MPa.The results showed that the 2D MOF exhibited a higher selectivity for CO_2 from CO_2/CH_4 and CH_4from CH_4/N_2 compared to the 3D MOF,even though it possessed a lower surface area and pore volume.The higher adsorption heats of gases on the 2D MOF inferred the strong adsorption potential energy in the layered MOFs.Dynamic separation experiments using CO_2/CH_4 and CH_4/N_2 mixtures on the two MOFs proved that the2 D MOF had a longer elution time than the 3D MOF as well as better separation abilities.展开更多
Two new isomeric Au complexes, Au（PPh3）（bmt）, have been synthesized via the reaction of Au（PPh3）CI with 2-benzimidazolethiol （Hbmt） in dichloromethane （CH2Cl2） solution. Their crystal structures were determi...Two new isomeric Au complexes, Au（PPh3）（bmt）, have been synthesized via the reaction of Au（PPh3）CI with 2-benzimidazolethiol （Hbmt） in dichloromethane （CH2Cl2） solution. Their crystal structures were determined by elemental analysis and single-crystal X-ray diffraction studies. Complex 1 crystallizes in the monoclinic system, space group C2/c with a = 19.589（2）, b = 21.1368（15）, c = 23.424（2） A, β = 108.346（4）°, V= 9206.1（14） A3, Mr = 1216.85, Dc = 1.756 g/cm3, μ = 6.566 mm^-1, F（000） = 4704, Z = 8, the final R = 0.0563 and wR = 0.1028 for 8125 reflections with I 〉 2σ（I）. Complex 2 crystallizes in the monoclinic system, space group P21/n with a = 9.627（3）, b = 21.384（8）, c = 22.308（8） A, β = 92.068（6）°, V= 4590（3） A3, Mr = 1216.85, Dc = 1.761 g/cms, μ = 6.585 mm^-1, F（000） = 2352, Z = 4, the final R = 0.0500 and wR = 0.0883 for 10477 reflections with I 〉 2σ（i）. X-ray diffraction studies reveal that complexes 1 and 2 both feature a 1D chain along the a axis.展开更多
In an attempt to synthesize an indole derivative,methyl 5-nitro-1H-indole-2-carb-oxylate,an isomeric change of methyl 2-[2-（4-nitrophenyl） hydrazono] propanoate from E to Z geometry was observed.The two isomers were...In an attempt to synthesize an indole derivative,methyl 5-nitro-1H-indole-2-carb-oxylate,an isomeric change of methyl 2-[2-（4-nitrophenyl） hydrazono] propanoate from E to Z geometry was observed.The two isomers were determined by single-crystal X-ray diffraction analysis.The Z isomer is stabilized in a six-membered ring conformation constructed by an intramolecular hydrogen bond.This isomeric change added a branched pathway in the mechanism of Fischer indole synthesis.展开更多
On the basis of Hauser-Feshbach theory and some approximations,parametrized formulae of isomeric cross section ratio including two adjustableparameters for(n,t)reaction at 14.6MeV are derived.By fitting these formulae...On the basis of Hauser-Feshbach theory and some approximations,parametrized formulae of isomeric cross section ratio including two adjustableparameters for(n,t)reaction at 14.6MeV are derived.By fitting these formulae to theavailable measured data,parameters are obtained and the systematic behaviour of theisomeric cross section ratio are studied.The isomeric cross section ratio predicted by thepresent work is in good agreement with the limited measured data.展开更多
Efficient,green,and economical removal of radioactive iodine (I_(2)) has drawn worldwide attention for the safe development of nuclear energy. Metal–organic frameworks (MOFs) have been demonstrated to be potential ca...Efficient,green,and economical removal of radioactive iodine (I_(2)) has drawn worldwide attention for the safe development of nuclear energy. Metal–organic frameworks (MOFs) have been demonstrated to be potential candidates for I_(2) capture. Herein we report the synthesis of two novel isomeric MOFs bearing stilbene moieties for exceptionally high I_(2) adsorption. [Cd(hsb-2)(tsbdc)]·0.5DMF (HSB-W8) and Cd(hsb-2)(tsbdc) (HSB-W9),which exhibit two-dimensional and twofold interpenetrated three-dimensional structures,respectively,have been assembled from hydrogenated Schiff base ligands,hsb-2 (1,2-bis(4’-pyridylmethylamino)-ethane) and trans-stilbene-4,4-dicarboxylate (tsbdc),and Cd(NO_(3))_(2) by the diffusion method. Such isomers arise from the different conformations of hsb-2 ligands controlled by diffusion temperatures. The π-electron-rich stilbene moieties render these Cd-MOFs ideal platforms for I_(2) capture. The adsorption capacities of HSB-W8 and HSB-W9 in I_(2) vapor at room temperature can reach up to 2.32 and 1.92 g g^(-1),respectively,which are comparable to the best-performing MOF materials reported so far. Furthermore,pseudo-second-order (PSO) kinetic model analysis,Fourier transform infrared (FT-IR) spectroscopy,Raman spectral analysis,density functional theory (DFT) calculations,and control experiments were performed to shed light on host–vip interactions and the iodine adsorption mechanism. This work develops a rational strategy to design and synthesise functional MOF materials for iodine adsorption.展开更多
In the present study,2,6-bis(diphenylphosphino)pyridine((Ph_(2)P)_(2)py)-supported cis-and trans-Pt_(2)Ag_(2)alkynyl complexes were prepared and characterized by X-ray crystallography.Although the cis-Pt_(2)Ag_(2)comp...In the present study,2,6-bis(diphenylphosphino)pyridine((Ph_(2)P)_(2)py)-supported cis-and trans-Pt_(2)Ag_(2)alkynyl complexes were prepared and characterized by X-ray crystallography.Although the cis-Pt_(2)Ag_(2)complexes are slightly emissive at ambient conditions,the trans-Pt_(2)Ag_(2)complexes exhibit moderate photoluminescence in dichloromethane and have strong emission in the solid state,originating from aromatic acetylide to(Ph_(2)P)_(2)py ligand-to-ligand charge transfer(^(3)LLCT)and Pt_(2)Ag_(2)cluster metal-centered(^(3)MC)triplet states.Remarkably,the trans-Pt_(2)Ag_(2)complex[Pt_(2)Ag_(2){(Ph_(2)P)_(2)py}_(2)(CuCC_(6)H_(5))_(4)](SO_(3)CF_(3))_(2)exhibit remarkable luminescent vapochromism with emission red-shifts of 100 nm in response to MeCN vapor,arising from intramolecular structural conversion from staggered to parallel arrangements of two face-to-face Pt(CuCC_(6)H_(5))_(2)moieties,which results in the alteration of the excited-state energy in the solid state as supported by TD-DFT studies.展开更多
In order to resolve the conflict between mechanical sensitivity and explosive performance,we utilized a retro-synthesis approach to design and synthesize the ligand 1H-imidazole-4-carbohydrazide(4-IMCA)and the complex...In order to resolve the conflict between mechanical sensitivity and explosive performance,we utilized a retro-synthesis approach to design and synthesize the ligand 1H-imidazole-4-carbohydrazide(4-IMCA)and the complex Cu(4-IMCA)_(2)(ClO_(4))_(2)(ECC-1).The structure of the product was confirmed by singlecrystal X-ray diffraction,IR and elemental analysis.The results showed that the physicochemical stability of ECC-1 was improved,including thermal stability(Td=200°C),mechanical sensitivity(IS=3 J,FS=7 N),and explosive performance.Moreover,laser ignition(P=22 W,τ=3 ms,E=66 mJ)and lead plate damage tests showed that the detonation ability of ECC-1 was not compromised.展开更多
The detection of antibiotics in environmental water or food is of great importance for protecting human health.New facile methods and high-performance sensory materials for the detection of antibiotics are highly desi...The detection of antibiotics in environmental water or food is of great importance for protecting human health.New facile methods and high-performance sensory materials for the detection of antibiotics are highly desirable.Herein,we present two isomeric In(Ⅲ)-MOFs,BUT-172 and BUT-173,which have slightly different three-dimensional(3D)open framework structures consisting of 1D infinite secondary building units(SBUs)and bridging tritopic carboxylate ligands.Both of the MOFs show a high porosity,and their micropore volumes and BET surface areas were estimated to be 0.66 and 0.67 cm^(3)g^(-1),and 1357 and 1366 m^(2)g^(-1),respectively.Stability tests revealed a high stability of the two MOFs in liquid water at room temperature.展开更多
The development of polymerized small-molecule acceptors(PSMAs)offers a promising route toward high-performance and stable organic solar cells(OSCs).Herein,we designed two isomeric PSMAs,PAS1 and PAS2,based on an asymm...The development of polymerized small-molecule acceptors(PSMAs)offers a promising route toward high-performance and stable organic solar cells(OSCs).Herein,we designed two isomeric PSMAs,PAS1 and PAS2,based on an asymmetric A1-DAD-A2 Y-shaped molecularbackbone,incorporating indandione(A1)and 3-dicyanomethylene-1-indanone(A2)as distinct terminal groups.Structural isomerism has been shown to significantly influence the physical,chemical,and optoelectronic properties of the two PSMAs.Moreover,isomerism markedly influences their dielectric constants,with the PAS2-based active layer exhibiting a higher value(3.10 vs.2.59).This enhancement reduces the charge-transfer state binding energy by approximately 16%,thereby promoting more efficient exciton dissociation.When blended with the donor JD40-BDD20 and processed using the non-halogenated solvent o-xylene,the PAS2-based film forms a more ordered nanoscale morphology,which promotes efficient charge transport and suppresses recombination losses.As a result,the PAS2-based device achieves a power conversion efficiency(PCE)of 15.5%,with an open circuit voltage(V_(OC))of 0.95 V,short circuit current(J_(SC))of 21.9 mA cm^(-2),and fill factor(FF)of 74.1%,outperforming the PAS1-based device,which exhibits a PCE of 13.5%.The asymmetric structure endows a blue-shifted absorption and an elevated lowest unoccupied molecular orbital(LUMO)energy level,making it suitable as a secondary acceptor for Y-type narrow-bandgap acceptors,and as a third component in the D18:L8-BO system.Notably,the ternary devices processed with o-xylene can be significantly improved and achieve a power conversion efficiency of 19.6%.These results underscore the potential of asymmetric isomeric PSMAs as versatile and efficient acceptors for realizing high-performance,halogen-free organic solar cells.展开更多
The^(nat)Mo(γ,xnp)^(95m,g)Nb photonuclear reaction was studied using the electron beam from the NSC KIPT linear accelerator LUE-40.The experiment was performed using the activation and off-lineγ-ray spectrometric te...The^(nat)Mo(γ,xnp)^(95m,g)Nb photonuclear reaction was studied using the electron beam from the NSC KIPT linear accelerator LUE-40.The experiment was performed using the activation and off-lineγ-ray spectrometric technique.The experimental isomeric yield ratio(IR)was determined for the reaction products^(95m,g)Nb at the bremsstrahlung end-point energy E_(γmax)range of 38-93 MeV.The obtained values of IR are in satisfactory agreement with the results of other studies and extend the range of previously known data.The theoretical values of the yields Y_(m,g)(E_(γmax))and the IR for the isomeric pair^(95m,g)Nb from the^(nat)Mo(γ,xnp)reaction were calculated using the partial cross-sectionsσ(E)from the TALYS1.95 code for six different level density models.For the investigated range of E_(γmax),the theoretical dependence of IR on energy was confirmed-the IR smoothly increases with increasing energy.The comparison showed a noticeable difference(more than 3.85 times)in the experimental IR relative to all theoretical estimates.展开更多
Three-quasiparticle K-isomeric states in odd-mass N=106 isotones within the A~180 mass region were systematically investigated using configuration-constrained potential energy surface calculations.The calculations suc...Three-quasiparticle K-isomeric states in odd-mass N=106 isotones within the A~180 mass region were systematically investigated using configuration-constrained potential energy surface calculations.The calculations succes sfully reproduced the excitation energies and deformations of the known high-K isomers in nuclei from 175Tm to 181Re.For the nuclei closer to the Z=82 shell closure(^(183)Ir,^(185)Au,and^(187)Tl),predictions of the configurations of the observed and yet-to-be-observed isomers are provided.The results reveal strong shape polarization,where the three-quasiparticle states are driven to larger deformations compared to the often shape-soft or spherical ground states.A particularly rich spectrum of shape coexistence is predicted in^(187)Tl,where several high-K three-quasiparticle configurations with distinct prolate,oblate,and triaxial shapes are found to coexist at similar excitation energies.Notably,the oblate-deformed K^(π)=29/2^(+)configuration at E_(x)=1839 keV was proposed to be responsible for a long-lived isomer.This study provides a comprehensive picture of shape evolution and coexistence in high-K multi-quasiparticle states,offering valuable insights for future experimental studies.展开更多
The photoneutron reaction^(18)Ta(y,3m)(178m,g)Ta was investigated with the beam from the NSC KIPT electron linear accelerator LUE-40.The measurements were performed using the residual y-activity method.The bremsstrahl...The photoneutron reaction^(18)Ta(y,3m)(178m,g)Ta was investigated with the beam from the NSC KIPT electron linear accelerator LUE-40.The measurements were performed using the residual y-activity method.The bremsstrahlung flux-averaged cross sections((E_(γmax))>.(r(E_(γmax))>m.<r(E_(γmax))g and the isomerie ratio of the re-action products d(E_(γmax))were measured.The theoretical values of the averaged cross-sections and isomeric ratio were calculated using the partial cross-sections from the TALYS1.95 code for different level density models LD 1-6..The obtained experimental d(E_(γmax))agree with the data in the lterature,but differ from the theoretical values in ab-solute magnitude and the behavior of the energy dependence.A comparison of the determined averaged cross-sec-tions with the calculated cross sections showed the best agreement for the case of the LD 5 model.展开更多
The isomeric structures, isomerization and decomposition of silylenoids H(2)SiMX (MX=KF, KCl, LiBr, NaBr and KBr) have been investigated by ab initio molecular orbital theory. These silylenoids have four kinds of very...The isomeric structures, isomerization and decomposition of silylenoids H(2)SiMX (MX=KF, KCl, LiBr, NaBr and KBr) have been investigated by ab initio molecular orbital theory. These silylenoids have four kinds of very similar equilibrium structures. The three-membered ring and p-complex structures should be stable and experimentally detectable. The lifetime of sigma-complex and tetrahedral structures would be very short and experimentally undetectable.展开更多
It remains elusive to realize the distinct catalysis of isomeric catalysts because it becomes challenging to identify structural isomers in the polydisperse nanoparticles.Herein we investigate catalysis of two geometr...It remains elusive to realize the distinct catalysis of isomeric catalysts because it becomes challenging to identify structural isomers in the polydisperse nanoparticles.Herein we investigate catalysis of two geometric isomers for 36-gold-atom nanoclusters with different Au cores arrangements but the same thiolate ligands,thereby providing access to isomer catalysts readily participate in a desired reaction.Compared to the Au_(36)(SR)_(24)with a one-dimensional(1D)layout of Au4 tetrahedral units,the Au_(36)(SR)_(24)with a two-dimensional(2D)layout of Au4 tetrahedral units is more effective for the intramolecular hydroamination of alkyne.Our study suggests that the exposed Au sties of the two Au_(36)(SR)_(24)catalysts favor different reaction intermediates and pathways.The intramolecular H transfer leads to intermediates with the C-N and with C=N for the 1D and 2D Au_(36)(SR)_(24)respectively,and hence the different on-site and off-site pathways for the successive reaction steps account for the different performances of the two Au_(36)(SR)_(24)catalysts.展开更多
In this work two isomeric semi-rigid multi-carboxylate ligands 3,5-bi(3-carboxyphenoxy)benzoic acid(3-H_3BCP), 3,5-bi(4-carboxyphenoxy)benzoic acid(4-H_(3)BCP) and two rigid ligands(bis-triazole 4-(4-(4H-1,2,4-triazol...In this work two isomeric semi-rigid multi-carboxylate ligands 3,5-bi(3-carboxyphenoxy)benzoic acid(3-H_3BCP), 3,5-bi(4-carboxyphenoxy)benzoic acid(4-H_(3)BCP) and two rigid ligands(bis-triazole 4-(4-(4H-1,2,4-triazol-4-yl)phenyl)-4 H-1,2,4-triazole(L^(1)), 2-(1H-pyrazol-3-yl)pyrazine(L^(2))) have been employed to react with Cd(Ⅱ) salts under similar solvothermal reactions. Two novel Cd(Ⅱ) mixed-ligand coordination polymers, namely, {[Cd_3(3-BCP)_(2)(L^(1))]·3H_(2)O}n(1) and [Cd(4-HBCP)(L^(2))]_n(2), have been isolated. 1 displays a rare 2D cluster-based network while 2 displays a 3D supramolecular network through weak interactions. Solid-state luminescent properties and thermal analyses of 1 and 2 also have been determined, indicating strong fluorescent emissions and good thermal stabilities. Different coordination modes of two semi-rigid multi-carboxylate ligands and L^(1) and L^(2) also have been briefly discussed, which also reveal the great potential in the construction of these novel mixed-ligand luminescent frameworks with diverse structural motifs and unique functional properties.展开更多
Electrolytes hold the key to realizing reliable zinc(Zn)anodes.Divergent organic molecules have been proven effective in stabilizing Zn anodes;however,irrational comparisons exist due to the uncontrolled molecular wei...Electrolytes hold the key to realizing reliable zinc(Zn)anodes.Divergent organic molecules have been proven effective in stabilizing Zn anodes;however,irrational comparisons exist due to the uncontrolled molecular weights and functional group amounts.In this work,two“isomeric molecules”:1,2-dimethoxyethane(DME)and 1-methoxy-2-propanol(PM),with identical molecular weights but different functional groups,have been studied as co-solvents in electrolytes,which have delivered distinct electrochemical performance.Experimental and simulative study indicates the dipole moment induced by the hydroxyl groups in PM(higher molecular polarity than ether groups in DME)reconstructs the space charge region,enhances the concentration of Zn^(2+)in the vicinity of Zn anodes,and in-situ derives different solid electrolyte interphase(SEI)models and electrode-electrolyte interfaces,resulting in exceptional cycling stability.Remarkably,the Zn||Cu cell with PM worked over 2000 cycles with high Coulombic efficiency(CE)of 99.7%.The Zn||Zn symmetric cell cycled over 2000 h at 1 mA·cm^(−2),and showed excellent stability at an ultrahigh current density of 10 mA·cm^(−2)and capacity of 20 mAh·cm^(−2)over 200 h(depth of discharge,DOD of 70%).The Zn||sodium vanadate pouch cell with a high mass loading of 6.3 mg·cm^(−2)and a high capacity of 24 mAh demonstrates superior cyclability after 570 h.This work can be a good starting point to provide reliable guidance on electrolyte design for practical aqueous Zn batteries.展开更多
The isomeric ratio of^(184m,g)Re and the half-life of^(184g)Re were measured in the ^(185)Re(n,2n)^(184)Re reaction at 14.8 MeV,and the uncertainty was discussed in detail.The measurements were performed using the act...The isomeric ratio of^(184m,g)Re and the half-life of^(184g)Re were measured in the ^(185)Re(n,2n)^(184)Re reaction at 14.8 MeV,and the uncertainty was discussed in detail.The measurements were performed using the activation method implemented for a rhenium sample using the K-400 neutron generator at the Chinese Academy of Engineering Physics(CAEP).Isomeric state and ground state nuclei of ^(184)Re were identified by their γ-ray spectra.To eliminate the effect of the γ-ray emitted from the isomer on the counting of the ground state characteristic peaks,the isomeric ratio of^(184m,g)Re was calculated to be 0.29±0.11 according to the neutron activation cross-section formula.This result is consistent with previous data within the uncertainty and can be used to determine parameters that characterize the dependence of the level density on the excitation energy and angular momentum.Through exponential function fitting and a detailed discussion of the uncertainty evaluation,the half-life of^(184g)Re was determined as 35.43±0.16 d,which is consistent with the currently recommended value;however,the uncertainty assessment of the latter was barely documented.In addition,this study indicates that the half-life of the ground state can be obtained by eliminating the contamination of γ-rays emitted from the isomer,which provides the possibility of determining the half-lives of nuclides containing isomers.展开更多
基金supported by the National Natural Science Foundation of China(No.62371263)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.SJCK25_1995).
文摘1 Introduction Recently,the increasing demand for advanced telecommunication systems has spurred extensive research into bandpass filters(BPFs),with particular emphasis on miniaturization,reduction of insertion loss(IL),and enhancement of upper stopband rejection(Huang et al.,2021;Snyder et al.,2021;Lin et al.,2023;Zeng et al.,2023).
文摘Mixed symmetry states are studied in the framework of the neutron-proton interacting boson model. It is found that some of the mixed symmetry states with moderate high spins change very fast with respect to the Majorana interaction. Under certain conditions, they become the yrast state or yrare state. These states are difficult to decay and become very stable. This study suggests that a possible new mode of isomers may exist due to the special nature in their proton and neutron degrees of freedom.
基金financially supported by the Ministry of Science and Technology of China (No. 2014CB643501)the National Natural Science Foundation of China (Nos. 21634004 and 51403070)+1 种基金the Foundation of Guangzhou Science and Technology Project (No. 201707020019)Zhi-Cheng Hu thanks the financial support from China Postdoctoral Science Foundation (No. 2017M622684)
文摘We present here a series of perylene diimide(PDI)based isomeric conjugated polymers for the application as efficient electron acceptors in all-polymer solar cells(all-PSCs).By copolymerizing PDI monomers with 1,4-diethynylbenzene(para-linkage)and 1,3-diethynylbenzene(meta-linkage),isomeric PDI based conjugated polymers with parallel and non-parallel PDI units inside backbones were obtained.It was found that para-linked conjugated polymer(PA)showed better solubility,strongerπ-πstacking,more favorable blend morphology,and better photovoltaic performance than those of meta-linked conjugated polymers(PM)did.Device based on PTB7-Th:PA(PTB7-Th:poly{4,8-bis[5-(2-ethylhexyl)-thiophen-2-yl]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl-alt-3-fluoro-2-[(2-ethylhexyl)-carbonyl]thieno[3,4-b]thiophene-4,6-diyl})showed significantly enhanced photovoltaic performance than that of PTB7-Th:MA(3.29%versus 0.92%).Moreover,the photovoltaic performance of these polymeric acceptors could be further improved via a terpolymeric strategy.By copolymerizing a small amount of meta-linkages into PA,the optimized terpolymeric acceptors enabled to enhance photovoltaic performance with improved the short-circuit current density(Jsc)and fill factor(FF),resulting in an improved power conversion efficiency(PCE)of 4.03%.
基金Supported by National Natural Science Foundation of China(No.21136007,No.51302184)the National Research Fund for Fundamental Key Projects(No.2014CB260402)
文摘Two isomeric metal-organic frameworks(MOFs) with 2-dimensional(2D) and 3-dimensional(3D) topologies both comprised of Cu(Ⅱ) and OTf(OTf = trifluoromethanesulfonate) ions were synthesized and characterized.The CO_2,CH_4 and N_2 adsorption properties of the two isomeric MOFs were investigated from 263 K to 298 K at0.1 MPa.The results showed that the 2D MOF exhibited a higher selectivity for CO_2 from CO_2/CH_4 and CH_4from CH_4/N_2 compared to the 3D MOF,even though it possessed a lower surface area and pore volume.The higher adsorption heats of gases on the 2D MOF inferred the strong adsorption potential energy in the layered MOFs.Dynamic separation experiments using CO_2/CH_4 and CH_4/N_2 mixtures on the two MOFs proved that the2 D MOF had a longer elution time than the 3D MOF as well as better separation abilities.
基金supported by the Youth Science Foundation of Jining University(2009QNKJ07)
文摘Two new isomeric Au complexes, Au（PPh3）（bmt）, have been synthesized via the reaction of Au（PPh3）CI with 2-benzimidazolethiol （Hbmt） in dichloromethane （CH2Cl2） solution. Their crystal structures were determined by elemental analysis and single-crystal X-ray diffraction studies. Complex 1 crystallizes in the monoclinic system, space group C2/c with a = 19.589（2）, b = 21.1368（15）, c = 23.424（2） A, β = 108.346（4）°, V= 9206.1（14） A3, Mr = 1216.85, Dc = 1.756 g/cm3, μ = 6.566 mm^-1, F（000） = 4704, Z = 8, the final R = 0.0563 and wR = 0.1028 for 8125 reflections with I 〉 2σ（I）. Complex 2 crystallizes in the monoclinic system, space group P21/n with a = 9.627（3）, b = 21.384（8）, c = 22.308（8） A, β = 92.068（6）°, V= 4590（3） A3, Mr = 1216.85, Dc = 1.761 g/cms, μ = 6.585 mm^-1, F（000） = 2352, Z = 4, the final R = 0.0500 and wR = 0.0883 for 10477 reflections with I 〉 2σ（i）. X-ray diffraction studies reveal that complexes 1 and 2 both feature a 1D chain along the a axis.
基金Supported by the Natural Science Foundation of Fujian Province (No. 2006 F5058)Fuzhou University (No. XRC-0527)
文摘In an attempt to synthesize an indole derivative,methyl 5-nitro-1H-indole-2-carb-oxylate,an isomeric change of methyl 2-[2-（4-nitrophenyl） hydrazono] propanoate from E to Z geometry was observed.The two isomers were determined by single-crystal X-ray diffraction analysis.The Z isomer is stabilized in a six-membered ring conformation constructed by an intramolecular hydrogen bond.This isomeric change added a branched pathway in the mechanism of Fischer indole synthesis.
文摘On the basis of Hauser-Feshbach theory and some approximations,parametrized formulae of isomeric cross section ratio including two adjustableparameters for(n,t)reaction at 14.6MeV are derived.By fitting these formulae to theavailable measured data,parameters are obtained and the systematic behaviour of theisomeric cross section ratio are studied.The isomeric cross section ratio predicted by thepresent work is in good agreement with the limited measured data.
基金supported by the National Natural Science Foundation of China(NSFC)(21901246)the Strategic Priority Research Program of CAS(XDB20010200)the Natural Science Foundation of Fujian Province(2019J01126).
文摘Efficient,green,and economical removal of radioactive iodine (I_(2)) has drawn worldwide attention for the safe development of nuclear energy. Metal–organic frameworks (MOFs) have been demonstrated to be potential candidates for I_(2) capture. Herein we report the synthesis of two novel isomeric MOFs bearing stilbene moieties for exceptionally high I_(2) adsorption. [Cd(hsb-2)(tsbdc)]·0.5DMF (HSB-W8) and Cd(hsb-2)(tsbdc) (HSB-W9),which exhibit two-dimensional and twofold interpenetrated three-dimensional structures,respectively,have been assembled from hydrogenated Schiff base ligands,hsb-2 (1,2-bis(4’-pyridylmethylamino)-ethane) and trans-stilbene-4,4-dicarboxylate (tsbdc),and Cd(NO_(3))_(2) by the diffusion method. Such isomers arise from the different conformations of hsb-2 ligands controlled by diffusion temperatures. The π-electron-rich stilbene moieties render these Cd-MOFs ideal platforms for I_(2) capture. The adsorption capacities of HSB-W8 and HSB-W9 in I_(2) vapor at room temperature can reach up to 2.32 and 1.92 g g^(-1),respectively,which are comparable to the best-performing MOF materials reported so far. Furthermore,pseudo-second-order (PSO) kinetic model analysis,Fourier transform infrared (FT-IR) spectroscopy,Raman spectral analysis,density functional theory (DFT) calculations,and control experiments were performed to shed light on host–vip interactions and the iodine adsorption mechanism. This work develops a rational strategy to design and synthesise functional MOF materials for iodine adsorption.
基金National Natural Science Foundation of China(Grants 92061202,21531008 and 21801242)Fujian Science and Technology Project(Grant 2020L3022)Strategic Priority Research Program of Chinese Academy of Sciences(Grant XDB20000000)。
文摘In the present study,2,6-bis(diphenylphosphino)pyridine((Ph_(2)P)_(2)py)-supported cis-and trans-Pt_(2)Ag_(2)alkynyl complexes were prepared and characterized by X-ray crystallography.Although the cis-Pt_(2)Ag_(2)complexes are slightly emissive at ambient conditions,the trans-Pt_(2)Ag_(2)complexes exhibit moderate photoluminescence in dichloromethane and have strong emission in the solid state,originating from aromatic acetylide to(Ph_(2)P)_(2)py ligand-to-ligand charge transfer(^(3)LLCT)and Pt_(2)Ag_(2)cluster metal-centered(^(3)MC)triplet states.Remarkably,the trans-Pt_(2)Ag_(2)complex[Pt_(2)Ag_(2){(Ph_(2)P)_(2)py}_(2)(CuCC_(6)H_(5))_(4)](SO_(3)CF_(3))_(2)exhibit remarkable luminescent vapochromism with emission red-shifts of 100 nm in response to MeCN vapor,arising from intramolecular structural conversion from staggered to parallel arrangements of two face-to-face Pt(CuCC_(6)H_(5))_(2)moieties,which results in the alteration of the excited-state energy in the solid state as supported by TD-DFT studies.
基金the generous financial support from the projects of NSFC(22175025).
文摘In order to resolve the conflict between mechanical sensitivity and explosive performance,we utilized a retro-synthesis approach to design and synthesize the ligand 1H-imidazole-4-carbohydrazide(4-IMCA)and the complex Cu(4-IMCA)_(2)(ClO_(4))_(2)(ECC-1).The structure of the product was confirmed by singlecrystal X-ray diffraction,IR and elemental analysis.The results showed that the physicochemical stability of ECC-1 was improved,including thermal stability(Td=200°C),mechanical sensitivity(IS=3 J,FS=7 N),and explosive performance.Moreover,laser ignition(P=22 W,τ=3 ms,E=66 mJ)and lead plate damage tests showed that the detonation ability of ECC-1 was not compromised.
基金support from the National Key R&D Program of China(Grant No.2018YFC1903105)the National Natural Science Foundation of China(Grant No.21601008)+1 种基金the Science Fund for Creative Research Groups of the National Natural Science Foundation of China(Grant No.51621003)the Beijing Natural Science Foundation(Grant No.2182005).
文摘The detection of antibiotics in environmental water or food is of great importance for protecting human health.New facile methods and high-performance sensory materials for the detection of antibiotics are highly desirable.Herein,we present two isomeric In(Ⅲ)-MOFs,BUT-172 and BUT-173,which have slightly different three-dimensional(3D)open framework structures consisting of 1D infinite secondary building units(SBUs)and bridging tritopic carboxylate ligands.Both of the MOFs show a high porosity,and their micropore volumes and BET surface areas were estimated to be 0.66 and 0.67 cm^(3)g^(-1),and 1357 and 1366 m^(2)g^(-1),respectively.Stability tests revealed a high stability of the two MOFs in liquid water at room temperature.
基金financial support from the National Natural Science Foundation of China(21805099)the financial support from the Jiangxi Provincial Natural Science Foundation(20224BAB204033)+3 种基金the Poly U Distinguished Postdoctoral Fellowship(1-YW4C)for the supportthe Guangdong Foundation of Basic and Applied Foundation(2024A1515012826)the Guangdong Polytechnic Normal University Teaching Reform Project(GSZLGC2023005,202211)the Province Key Construction Discipline Research Ability Improvement Project(2024ZDJS027)for the support。
文摘The development of polymerized small-molecule acceptors(PSMAs)offers a promising route toward high-performance and stable organic solar cells(OSCs).Herein,we designed two isomeric PSMAs,PAS1 and PAS2,based on an asymmetric A1-DAD-A2 Y-shaped molecularbackbone,incorporating indandione(A1)and 3-dicyanomethylene-1-indanone(A2)as distinct terminal groups.Structural isomerism has been shown to significantly influence the physical,chemical,and optoelectronic properties of the two PSMAs.Moreover,isomerism markedly influences their dielectric constants,with the PAS2-based active layer exhibiting a higher value(3.10 vs.2.59).This enhancement reduces the charge-transfer state binding energy by approximately 16%,thereby promoting more efficient exciton dissociation.When blended with the donor JD40-BDD20 and processed using the non-halogenated solvent o-xylene,the PAS2-based film forms a more ordered nanoscale morphology,which promotes efficient charge transport and suppresses recombination losses.As a result,the PAS2-based device achieves a power conversion efficiency(PCE)of 15.5%,with an open circuit voltage(V_(OC))of 0.95 V,short circuit current(J_(SC))of 21.9 mA cm^(-2),and fill factor(FF)of 74.1%,outperforming the PAS1-based device,which exhibits a PCE of 13.5%.The asymmetric structure endows a blue-shifted absorption and an elevated lowest unoccupied molecular orbital(LUMO)energy level,making it suitable as a secondary acceptor for Y-type narrow-bandgap acceptors,and as a third component in the D18:L8-BO system.Notably,the ternary devices processed with o-xylene can be significantly improved and achieve a power conversion efficiency of 19.6%.These results underscore the potential of asymmetric isomeric PSMAs as versatile and efficient acceptors for realizing high-performance,halogen-free organic solar cells.
文摘The^(nat)Mo(γ,xnp)^(95m,g)Nb photonuclear reaction was studied using the electron beam from the NSC KIPT linear accelerator LUE-40.The experiment was performed using the activation and off-lineγ-ray spectrometric technique.The experimental isomeric yield ratio(IR)was determined for the reaction products^(95m,g)Nb at the bremsstrahlung end-point energy E_(γmax)range of 38-93 MeV.The obtained values of IR are in satisfactory agreement with the results of other studies and extend the range of previously known data.The theoretical values of the yields Y_(m,g)(E_(γmax))and the IR for the isomeric pair^(95m,g)Nb from the^(nat)Mo(γ,xnp)reaction were calculated using the partial cross-sectionsσ(E)from the TALYS1.95 code for six different level density models.For the investigated range of E_(γmax),the theoretical dependence of IR on energy was confirmed-the IR smoothly increases with increasing energy.The comparison showed a noticeable difference(more than 3.85 times)in the experimental IR relative to all theoretical estimates.
基金supported by the National Natural Science Foundation of China(No.12275369)。
文摘Three-quasiparticle K-isomeric states in odd-mass N=106 isotones within the A~180 mass region were systematically investigated using configuration-constrained potential energy surface calculations.The calculations succes sfully reproduced the excitation energies and deformations of the known high-K isomers in nuclei from 175Tm to 181Re.For the nuclei closer to the Z=82 shell closure(^(183)Ir,^(185)Au,and^(187)Tl),predictions of the configurations of the observed and yet-to-be-observed isomers are provided.The results reveal strong shape polarization,where the three-quasiparticle states are driven to larger deformations compared to the often shape-soft or spherical ground states.A particularly rich spectrum of shape coexistence is predicted in^(187)Tl,where several high-K three-quasiparticle configurations with distinct prolate,oblate,and triaxial shapes are found to coexist at similar excitation energies.Notably,the oblate-deformed K^(π)=29/2^(+)configuration at E_(x)=1839 keV was proposed to be responsible for a long-lived isomer.This study provides a comprehensive picture of shape evolution and coexistence in high-K multi-quasiparticle states,offering valuable insights for future experimental studies.
文摘The photoneutron reaction^(18)Ta(y,3m)(178m,g)Ta was investigated with the beam from the NSC KIPT electron linear accelerator LUE-40.The measurements were performed using the residual y-activity method.The bremsstrahlung flux-averaged cross sections((E_(γmax))>.(r(E_(γmax))>m.<r(E_(γmax))g and the isomerie ratio of the re-action products d(E_(γmax))were measured.The theoretical values of the averaged cross-sections and isomeric ratio were calculated using the partial cross-sections from the TALYS1.95 code for different level density models LD 1-6..The obtained experimental d(E_(γmax))agree with the data in the lterature,but differ from the theoretical values in ab-solute magnitude and the behavior of the energy dependence.A comparison of the determined averaged cross-sec-tions with the calculated cross sections showed the best agreement for the case of the LD 5 model.
基金Project supported by the National Natural Science Fundaion of China.
文摘The isomeric structures, isomerization and decomposition of silylenoids H(2)SiMX (MX=KF, KCl, LiBr, NaBr and KBr) have been investigated by ab initio molecular orbital theory. These silylenoids have four kinds of very similar equilibrium structures. The three-membered ring and p-complex structures should be stable and experimentally detectable. The lifetime of sigma-complex and tetrahedral structures would be very short and experimentally undetectable.
基金supports from Fundamental Research Funds for the Central Universities,Programs for high-level entrepreneurial and innovative talents introduction of Jiangsu Province,and Scientific and Technological Innovation Foundation of Shunde Graduate School of USTB(No.BK19BE024).
文摘It remains elusive to realize the distinct catalysis of isomeric catalysts because it becomes challenging to identify structural isomers in the polydisperse nanoparticles.Herein we investigate catalysis of two geometric isomers for 36-gold-atom nanoclusters with different Au cores arrangements but the same thiolate ligands,thereby providing access to isomer catalysts readily participate in a desired reaction.Compared to the Au_(36)(SR)_(24)with a one-dimensional(1D)layout of Au4 tetrahedral units,the Au_(36)(SR)_(24)with a two-dimensional(2D)layout of Au4 tetrahedral units is more effective for the intramolecular hydroamination of alkyne.Our study suggests that the exposed Au sties of the two Au_(36)(SR)_(24)catalysts favor different reaction intermediates and pathways.The intramolecular H transfer leads to intermediates with the C-N and with C=N for the 1D and 2D Au_(36)(SR)_(24)respectively,and hence the different on-site and off-site pathways for the successive reaction steps account for the different performances of the two Au_(36)(SR)_(24)catalysts.
基金Scientific Research Project of Tianjin Education Commission(2018KJ250)National Natural Science Foundation of China(21501196)。
文摘In this work two isomeric semi-rigid multi-carboxylate ligands 3,5-bi(3-carboxyphenoxy)benzoic acid(3-H_3BCP), 3,5-bi(4-carboxyphenoxy)benzoic acid(4-H_(3)BCP) and two rigid ligands(bis-triazole 4-(4-(4H-1,2,4-triazol-4-yl)phenyl)-4 H-1,2,4-triazole(L^(1)), 2-(1H-pyrazol-3-yl)pyrazine(L^(2))) have been employed to react with Cd(Ⅱ) salts under similar solvothermal reactions. Two novel Cd(Ⅱ) mixed-ligand coordination polymers, namely, {[Cd_3(3-BCP)_(2)(L^(1))]·3H_(2)O}n(1) and [Cd(4-HBCP)(L^(2))]_n(2), have been isolated. 1 displays a rare 2D cluster-based network while 2 displays a 3D supramolecular network through weak interactions. Solid-state luminescent properties and thermal analyses of 1 and 2 also have been determined, indicating strong fluorescent emissions and good thermal stabilities. Different coordination modes of two semi-rigid multi-carboxylate ligands and L^(1) and L^(2) also have been briefly discussed, which also reveal the great potential in the construction of these novel mixed-ligand luminescent frameworks with diverse structural motifs and unique functional properties.
基金We acknowledge the financial support from the Open Research Fund of Songshan Lake Materials Laboratory(No.2021SLABFN04)the National Natural Science Foundation of China(Nos.22005207 and U20A20249)the Regional Innovation and Development Joint Fund,and the Science and Technology Program of Guangdong Province of China(No.2022A0505030028).
文摘Electrolytes hold the key to realizing reliable zinc(Zn)anodes.Divergent organic molecules have been proven effective in stabilizing Zn anodes;however,irrational comparisons exist due to the uncontrolled molecular weights and functional group amounts.In this work,two“isomeric molecules”:1,2-dimethoxyethane(DME)and 1-methoxy-2-propanol(PM),with identical molecular weights but different functional groups,have been studied as co-solvents in electrolytes,which have delivered distinct electrochemical performance.Experimental and simulative study indicates the dipole moment induced by the hydroxyl groups in PM(higher molecular polarity than ether groups in DME)reconstructs the space charge region,enhances the concentration of Zn^(2+)in the vicinity of Zn anodes,and in-situ derives different solid electrolyte interphase(SEI)models and electrode-electrolyte interfaces,resulting in exceptional cycling stability.Remarkably,the Zn||Cu cell with PM worked over 2000 cycles with high Coulombic efficiency(CE)of 99.7%.The Zn||Zn symmetric cell cycled over 2000 h at 1 mA·cm^(−2),and showed excellent stability at an ultrahigh current density of 10 mA·cm^(−2)and capacity of 20 mAh·cm^(−2)over 200 h(depth of discharge,DOD of 70%).The Zn||sodium vanadate pouch cell with a high mass loading of 6.3 mg·cm^(−2)and a high capacity of 24 mAh demonstrates superior cyclability after 570 h.This work can be a good starting point to provide reliable guidance on electrolyte design for practical aqueous Zn batteries.
基金Supported by the National Natural Science Foundation of China(11975113)。
文摘The isomeric ratio of^(184m,g)Re and the half-life of^(184g)Re were measured in the ^(185)Re(n,2n)^(184)Re reaction at 14.8 MeV,and the uncertainty was discussed in detail.The measurements were performed using the activation method implemented for a rhenium sample using the K-400 neutron generator at the Chinese Academy of Engineering Physics(CAEP).Isomeric state and ground state nuclei of ^(184)Re were identified by their γ-ray spectra.To eliminate the effect of the γ-ray emitted from the isomer on the counting of the ground state characteristic peaks,the isomeric ratio of^(184m,g)Re was calculated to be 0.29±0.11 according to the neutron activation cross-section formula.This result is consistent with previous data within the uncertainty and can be used to determine parameters that characterize the dependence of the level density on the excitation energy and angular momentum.Through exponential function fitting and a detailed discussion of the uncertainty evaluation,the half-life of^(184g)Re was determined as 35.43±0.16 d,which is consistent with the currently recommended value;however,the uncertainty assessment of the latter was barely documented.In addition,this study indicates that the half-life of the ground state can be obtained by eliminating the contamination of γ-rays emitted from the isomer,which provides the possibility of determining the half-lives of nuclides containing isomers.
