Hexagonal ultrathin WO3 nano-ribbons （HUWNRs） of subnanometer thicknesses, 2-5 nm widths, and lengths of up to several micrometers were prepared by a solvothermal method. The as-prepared HUWNRs grow along the [001] ...Hexagonal ultrathin WO3 nano-ribbons （HUWNRs） of subnanometer thicknesses, 2-5 nm widths, and lengths of up to several micrometers were prepared by a solvothermal method. The as-prepared HUWNRs grow along the [001] direction, and the main exposed facet is the （720） crystal plane. The HUWNRs exhibit good electrochemical performance as an anode material in lithium ion batteries because of their unique structure. It is believed that these unique materials may be applied in many fields.展开更多
Organic heterostructures with precisely defined compositions,architectures,and interfaces are considered promising building blocks for integrated optoelectronic devices.However,it remains a great challenge to rational...Organic heterostructures with precisely defined compositions,architectures,and interfaces are considered promising building blocks for integrated optoelectronic devices.However,it remains a great challenge to rationally design and synthesize a heterostructure with tunable performance for promising applications such as optoelectronic devices.Herein,we report a universal strategy for the synthesis of organic lateral heterostructures(OLHs)with tunable function and optical properties.We fabricated cocrystals based on the tunable intermolecular distance(dπ–πfrom 3.33 to 3.48Å)ofBenzo[ghi]perylene(BGP)-based driven by arene-perfluoroarene interaction or charge transfer interaction;these different components were selectively constructed into organic solid solution microwires or OLHs.Importantly,the solid solution microwires obtained could be epitaxially grown on the BGP-tetrabromophthalicanhydride trunk microwire to construct a series of OLHs microwires,which led to the successful demonstration of both photonic signal conversion and optical logic gate in all-color wavelength.This work gives a new insight into the fine synthesis of heterostructures with tunable structures/performances,providing predictable synthetic pathways to multifunctional organic heterostructures for the future realization of integrated optoelectronics.展开更多
The proper orthogonal decomposition(POD) method was applied to analyzing the database obtained from the direct numerical simulation(DNS) of supersonic plane mixing layers.The effect of different forms of the inner pro...The proper orthogonal decomposition(POD) method was applied to analyzing the database obtained from the direct numerical simulation(DNS) of supersonic plane mixing layers.The effect of different forms of the inner products in the POD method was investigated.It was observed that the mean flow contributes to a predominant part of the total flow energy,and the energy spectrum of the turbulence fluctuations covers a wide range of POD modes.The patterns of leading(high energy) POD modes reveal that the flow structures exhibit spanwise counter rotating rolls,as well as oblique vortices.These flow patterns are insensitive to the velocity of the observer.As the convective Mach number increases,the energy spectrum be-comes wider,the leading POD modes contain more complicated structures,and the flow becomes more chaotic.展开更多
For solution prepared perovskite solar cells,metal halide perovskite materials with low-dimensional(LD)are flexibly employed in 3D perovskite solar cells to promote efficiency and long-term stability.In this review,th...For solution prepared perovskite solar cells,metal halide perovskite materials with low-dimensional(LD)are flexibly employed in 3D perovskite solar cells to promote efficiency and long-term stability.In this review,the various structures,properties,and applications of LD perovskites are firstly summarized and discussed.To take advantage of LD materials,LD perovskites are introduced in the 3D bulk and/or the interface between the perovskite thin film and the carrier transporting layer to passivate the gain boundary defects while providing the stability advantage of LD materials.Therefore,the preparation methods and crystallization control of the LD perovskite layers are discussed in depth.Then,the combined devices using both LD and 3D components are reviewed on the basis of device design,cell structure,interface charge transfer,energy lever alignment,and synergistic improvement of both efficiency and stability.Finally,the challenges and expectations are speculated for further development of perovskite solar cells.展开更多
Anti-perovskites A3SnO(A=Ca,Sr,and Ba)are an important class of materials due to the emergence of Dirac cones and tiny mass gaps in their band structures originating from an intricate interplay of crystal symmetry,spi...Anti-perovskites A3SnO(A=Ca,Sr,and Ba)are an important class of materials due to the emergence of Dirac cones and tiny mass gaps in their band structures originating from an intricate interplay of crystal symmetry,spin–orbit coupling,and band overlap.This provides an exciting playground for modulating their electronic properties in the two-dimensional(2D)limit.Herein,we employ first-principles density functional theory(DFT)calculations by combining dispersion-corrected SCAN+rVV10 and mBJ functionals for a comprehensive side-by-side comparison of the structural,thermodynamic,dynamical,mechanical,electronic,and thermoelectric properties of bulk and monolayer(one unit cell thick)A3SnO anti-perovskites.Our results show that 2D monolayers derived from bulk A3SnO anti-perovskites are structurally and energetically stable.Moreover,Rashba-type splitting in the electronic structure of Ca3SnO and Sr3SnO monolayers is observed owing to strong spin–orbit coupling and inversion asymmetry.On the other hand,monolayer Ba3SnO exhibits Dirac cone at the high-symmetryΓpoint due to the domination of band overlap.Based on the predicted electronic transport properties,it is shown that inversion asymmetry plays an essential character such that the monolayers Ca3SnO and Sr3SnO outperform thermoelectric performance of their bulk counterparts.展开更多
Sn-based perovskites are promising thin-film photovoltaic materials for their ideal bandgap and the eco-friendliness of Sn,but the performance of Sn-based perovskite solar cells is hindered by the short carrier diffus...Sn-based perovskites are promising thin-film photovoltaic materials for their ideal bandgap and the eco-friendliness of Sn,but the performance of Sn-based perovskite solar cells is hindered by the short carrier diffusion length and large defect density in nominally-synthesized Sn-based perovskite films.Herein we demonstrate that a long carrier diffusion length is achievable in quasi-2D Sn-based perovskite films consisting of high-member low-dimensional Ruddlesden-Popper(RP)phases with a preferred crystal orientation distribution.The key to the film synthesis is the use of a molecular additive formed by phenylethylammonium cations and optimally mixed halide-pseudohalide anions,which favorably tailors the quasi-2D Sn-based perovskite crystallization kinetics.The high-member RP film structure effectively enhances device short-circuit current density,giving rise to an increased power conversion efficiency(PCE)of 14.6%.The resulting device demonstrates a near-unity shelf stability upon1,000 h in nitrogen.A high reproductivity is also achieved with a count of 50 devices showing PCEs within a narrow range from minimum 13.0%to maximum 14.6%.展开更多
In this paper,the problem of high-dimensional multivariate analysis of variance is investigated under a low-dimensional factor structure which violates some vital assumptions on covariance matrix in some existing lite...In this paper,the problem of high-dimensional multivariate analysis of variance is investigated under a low-dimensional factor structure which violates some vital assumptions on covariance matrix in some existing literature.We propose a new test and derive that the asymptotic distribution of the test statistic is a weighted distribution of chi-squares of 1 degree of freedom under the null hypothesis and mild conditions.We provide numerical studies on both sizes and powers to illustrate performance of the proposed test.展开更多
In this paper, a novel Magnetic Resonance (MR) reconstruction framework which combines image-wise and patch-wise sparse prior is proposed. For addressing, a truncated beta-Bernoulli process is firstly employed to enfo...In this paper, a novel Magnetic Resonance (MR) reconstruction framework which combines image-wise and patch-wise sparse prior is proposed. For addressing, a truncated beta-Bernoulli process is firstly employed to enforce sparsity on overlapping image patches emphasizing local structures. Due to its properties, beta-Bernoulli process can adaptive infer the sparsity (number of non-zero coefficients) of each patch, an appropriate dictionary, and the noise variance simultaneously, which are prerequisite for iterative image reconstruction. Secondly, a General Gaussian Distribution (GGD) prior is introduced to engage image-wise sparsity for wavelet coefficients, which can be then estimated by a threshold denoising algorithm. Finally, MR image is reconstructed by patch-wise estimation, image-wise estimation and under-sampled k-space data with least square data fitting. Experimental results have demonstrated that proposed approach exhibits excellent reconstruction performance. Moreover, if the image is full of similar low-dimensional-structures, proposed algorithm has dramatically improved Peak Signal to Noise Ratio (PSNR) 7～9 dB, with comparisons to other state-of-art compressive sampling methods.展开更多
Crystalline ErCl_(3) nanowires have been fabricated in single-walled carbon nanotubes(SWCNTs)with high yield(~90%),and the structural and magnetic properties of the resulting ErCl_(3) nanowires encapsulated in SWCNTs(...Crystalline ErCl_(3) nanowires have been fabricated in single-walled carbon nanotubes(SWCNTs)with high yield(~90%),and the structural and magnetic properties of the resulting ErCl_(3) nanowires encapsulated in SWCNTs(ErCl_(3)@SWCNTs)characterized.Encapsulation under high temperature and vacuum using high quality SWCNTs results in a high fi lling-ratio of ErCl_(3) nanowires in the SWCNTs.The high fi lling-ratio of ErCl_(3) nanowires and the use of highly pure SWCNTs with only a small amount of residual Fe catalyst nanoparticles enabled us to observe the magnetic properties of ErCl_(3)@SWCNTs.Structure determination based on simulated annealing calculations and high-resolution transmission electron microscope(HRTEM)image simulations revealed that the structure of the ErCl_(3) nanowires is unusual with respect to the coordination environment of the Eu3+ions.This work opens up new possibilities to fabricate various metal complex nanowires with high yield and may also be of more general importance in understanding and exploring magnetic properties in low-dimensional magnetic systems.展开更多
Metal halide perovskites possess appealing optoelectronic properties and have been widely applied for solar energy harvesting and light emitting.Although perovskite solar cells(PeSCs)and perovskite light-emitting diod...Metal halide perovskites possess appealing optoelectronic properties and have been widely applied for solar energy harvesting and light emitting.Although perovskite solar cells(PeSCs)and perovskite light-emitting diodes(PeLEDs)have been developed rapidly in recent years,there are still no universal rules for the selection of perovskites to achieve high-performance optoelectronic devices.In this review,the working mechanisms of PeSCs and PeLEDs are first demonstrated with the discussion on the factors which determine the device performance.We then examine the optoelectronic properties of perovskites with structures modulated from 3D,2D,1D to 0D,and analyze the corresponding structure-property relationships in terms of photo-electric and electric-photo conversion processes.Based on the unique optoelectronic properties of structurally modulated perovskites,we put forward the concept of structural assembling engineering that integrate the merits of different types of perovskites within one matrix and elaborate their excellent properties for applications of both PeSCs and PeLEDs.Finally,we discuss the potential challenges and provide our perspectives on the structural assembling engineering of perovskites for future optoelectronic applications.展开更多
Two new low-dimensional Mn(Ⅱ)coordination compounds of Mn(H2pimdc)2(phen)(compound 1)and[Mn(Hpimdc)(phen)]n·nH2O(compound 2)were synthesized,where H3pimdc is a 2-propyl-imidazole-4,5-dicarboxylic acid and phen i...Two new low-dimensional Mn(Ⅱ)coordination compounds of Mn(H2pimdc)2(phen)(compound 1)and[Mn(Hpimdc)(phen)]n·nH2O(compound 2)were synthesized,where H3pimdc is a 2-propyl-imidazole-4,5-dicarboxylic acid and phen is 1,10-phenanthroline.Both compounds were thoroughly analyzed by X-ray single-crystal diffraction,element analysis,IR spectra,PXRD and thermal analysis.X-ray single-crystal diffraction analyses indicate that the phen ligands terminate metal ions on two sides to prevent the linkage between the neighboring metal ions into a higher dimensional structure in compounds 1 and 2.Compound 1 is constructed from mononuclear molecules which form the 1D helical supramolecular chain by N-H···O hydrogen bonds.In compound 2,Hpimdc is a tetradentate bridging ligand,which binds Mn(Ⅱ)ions to generate a single-stranded right helical chain parallel to the b axis.These 1D chains are additionally coupled by H-bonds as well asπ···πstacking interactions,which formed a 3D supramolecular structure.Additionally,compound 2 demonstrated temperature-dependent magnetic susceptibility and negative value ofθ(equal to-9.09 K),which is indicative of weak antiferromagnetic interactions between Mn(Ⅱ)ions.展开更多
基金This work was supported by the State Key Project of Fundamental Research for Nanoscience and Nanotechnology （Nos. 2011CB932401, 2011CBA00500, and 2012CB224802）, and the National Natural Science Foundation of China （Nos. 21221062, 21131004, and 21390393）. The authors thank Electron Microscopy Laboratory of Peking University for the help with HRTEM analysis.
文摘Hexagonal ultrathin WO3 nano-ribbons （HUWNRs） of subnanometer thicknesses, 2-5 nm widths, and lengths of up to several micrometers were prepared by a solvothermal method. The as-prepared HUWNRs grow along the [001] direction, and the main exposed facet is the （720） crystal plane. The HUWNRs exhibit good electrochemical performance as an anode material in lithium ion batteries because of their unique structure. It is believed that these unique materials may be applied in many fields.
基金support from the National Natural Science Foundation of China(grant nos.52173177 and 21971185)funded by the Collaborative Innovation Center of Suzhou Nano Science and Technology(CIC-Nano)the“111”Project of the State Administration of Foreign Experts Affairs of China.
文摘Organic heterostructures with precisely defined compositions,architectures,and interfaces are considered promising building blocks for integrated optoelectronic devices.However,it remains a great challenge to rationally design and synthesize a heterostructure with tunable performance for promising applications such as optoelectronic devices.Herein,we report a universal strategy for the synthesis of organic lateral heterostructures(OLHs)with tunable function and optical properties.We fabricated cocrystals based on the tunable intermolecular distance(dπ–πfrom 3.33 to 3.48Å)ofBenzo[ghi]perylene(BGP)-based driven by arene-perfluoroarene interaction or charge transfer interaction;these different components were selectively constructed into organic solid solution microwires or OLHs.Importantly,the solid solution microwires obtained could be epitaxially grown on the BGP-tetrabromophthalicanhydride trunk microwire to construct a series of OLHs microwires,which led to the successful demonstration of both photonic signal conversion and optical logic gate in all-color wavelength.This work gives a new insight into the fine synthesis of heterostructures with tunable structures/performances,providing predictable synthetic pathways to multifunctional organic heterostructures for the future realization of integrated optoelectronics.
基金the National Natural Science Foundation of China(Grant No.10232020,90505005)
文摘The proper orthogonal decomposition(POD) method was applied to analyzing the database obtained from the direct numerical simulation(DNS) of supersonic plane mixing layers.The effect of different forms of the inner products in the POD method was investigated.It was observed that the mean flow contributes to a predominant part of the total flow energy,and the energy spectrum of the turbulence fluctuations covers a wide range of POD modes.The patterns of leading(high energy) POD modes reveal that the flow structures exhibit spanwise counter rotating rolls,as well as oblique vortices.These flow patterns are insensitive to the velocity of the observer.As the convective Mach number increases,the energy spectrum be-comes wider,the leading POD modes contain more complicated structures,and the flow becomes more chaotic.
基金supported by funds from the National Natural Science Foundation of China (grant nos.62004121 and 62174103)the supports of the Scientific and Technological Innovation Team Project of Shaanxi Innovation Capability Support Plan (2022TD-30)+1 种基金Youth Innovation Team of Shaanxi Universities (2019–2022)Top Young Talents Project of“Special Support Program for High Level Talents”in Shaanxi Province,China (2018–2023)。
文摘For solution prepared perovskite solar cells,metal halide perovskite materials with low-dimensional(LD)are flexibly employed in 3D perovskite solar cells to promote efficiency and long-term stability.In this review,the various structures,properties,and applications of LD perovskites are firstly summarized and discussed.To take advantage of LD materials,LD perovskites are introduced in the 3D bulk and/or the interface between the perovskite thin film and the carrier transporting layer to passivate the gain boundary defects while providing the stability advantage of LD materials.Therefore,the preparation methods and crystallization control of the LD perovskite layers are discussed in depth.Then,the combined devices using both LD and 3D components are reviewed on the basis of device design,cell structure,interface charge transfer,energy lever alignment,and synergistic improvement of both efficiency and stability.Finally,the challenges and expectations are speculated for further development of perovskite solar cells.
基金The computations were enabled by resources provided by the Swedish National Infrastructure for Computing(SNIC)at HPC2N and NSC partially funded by the Swedish Research Council through grant agreement no.2018-05973.
文摘Anti-perovskites A3SnO(A=Ca,Sr,and Ba)are an important class of materials due to the emergence of Dirac cones and tiny mass gaps in their band structures originating from an intricate interplay of crystal symmetry,spin–orbit coupling,and band overlap.This provides an exciting playground for modulating their electronic properties in the two-dimensional(2D)limit.Herein,we employ first-principles density functional theory(DFT)calculations by combining dispersion-corrected SCAN+rVV10 and mBJ functionals for a comprehensive side-by-side comparison of the structural,thermodynamic,dynamical,mechanical,electronic,and thermoelectric properties of bulk and monolayer(one unit cell thick)A3SnO anti-perovskites.Our results show that 2D monolayers derived from bulk A3SnO anti-perovskites are structurally and energetically stable.Moreover,Rashba-type splitting in the electronic structure of Ca3SnO and Sr3SnO monolayers is observed owing to strong spin–orbit coupling and inversion asymmetry.On the other hand,monolayer Ba3SnO exhibits Dirac cone at the high-symmetryΓpoint due to the domination of band overlap.Based on the predicted electronic transport properties,it is shown that inversion asymmetry plays an essential character such that the monolayers Ca3SnO and Sr3SnO outperform thermoelectric performance of their bulk counterparts.
基金financially supported from the National Key Research and Development Program of China(2021YFA0715502)the National Natural Science Foundation of China(61935016,92056119,22175118)+9 种基金the Science and Technology Commission of Shanghai Municipality(20XD1402500,20JC1415800)Shanghai Tech start-up fundingthe Early Career Scheme(22300221)from the Hong Kong Research Grant Councilthe Excellent Young Scientists Funds(52222318)from National Natural Science Foundation of Chinathe start-up grants,the Initiation Grant-Faculty Niche Research Areas(IG-FNRA)2020/21the Interdisciplinary Research Matching Scheme(IRMS)2020/21 of Hong Kong Baptist Universitysupport from the Hong Kong Research Grant Council(16302520)Seed Funding from the University Research Committee(URC)of the University of Hong Kongpartially supported by the Centre for High-Resolution Electron Microscopy(ChEM),SPST,Shanghai Tech University under contract No.EM02161943the Analytical Instrumentation Center,SPST,Shanghai Tech University under contract No.SPST-AIC10112914。
文摘Sn-based perovskites are promising thin-film photovoltaic materials for their ideal bandgap and the eco-friendliness of Sn,but the performance of Sn-based perovskite solar cells is hindered by the short carrier diffusion length and large defect density in nominally-synthesized Sn-based perovskite films.Herein we demonstrate that a long carrier diffusion length is achievable in quasi-2D Sn-based perovskite films consisting of high-member low-dimensional Ruddlesden-Popper(RP)phases with a preferred crystal orientation distribution.The key to the film synthesis is the use of a molecular additive formed by phenylethylammonium cations and optimally mixed halide-pseudohalide anions,which favorably tailors the quasi-2D Sn-based perovskite crystallization kinetics.The high-member RP film structure effectively enhances device short-circuit current density,giving rise to an increased power conversion efficiency(PCE)of 14.6%.The resulting device demonstrates a near-unity shelf stability upon1,000 h in nitrogen.A high reproductivity is also achieved with a count of 50 devices showing PCEs within a narrow range from minimum 13.0%to maximum 14.6%.
基金supported by the National Statistical Science Research Program(No.2020LY002)the National Natural Science Foundation of China(Nos.11601008,11526070)+2 种基金Doctor Startup Foundation of Anhui Normal University(No.2016XJJ101)supported by Anhui Provincial Natural Science Foundation(No.2008085MA08)supported by Anhui Provincial Natural Science Foundation(No.1908085MA20).
文摘In this paper,the problem of high-dimensional multivariate analysis of variance is investigated under a low-dimensional factor structure which violates some vital assumptions on covariance matrix in some existing literature.We propose a new test and derive that the asymptotic distribution of the test statistic is a weighted distribution of chi-squares of 1 degree of freedom under the null hypothesis and mild conditions.We provide numerical studies on both sizes and powers to illustrate performance of the proposed test.
基金Supported by the National Natural Science Foundation of China (No. 30900328, 61172179)the Fundamental Research Funds for the Central Universities (No.2011121051)the Natural Science Foundation of Fujian Province of China (No. 2012J05160)
文摘In this paper, a novel Magnetic Resonance (MR) reconstruction framework which combines image-wise and patch-wise sparse prior is proposed. For addressing, a truncated beta-Bernoulli process is firstly employed to enforce sparsity on overlapping image patches emphasizing local structures. Due to its properties, beta-Bernoulli process can adaptive infer the sparsity (number of non-zero coefficients) of each patch, an appropriate dictionary, and the noise variance simultaneously, which are prerequisite for iterative image reconstruction. Secondly, a General Gaussian Distribution (GGD) prior is introduced to engage image-wise sparsity for wavelet coefficients, which can be then estimated by a threshold denoising algorithm. Finally, MR image is reconstructed by patch-wise estimation, image-wise estimation and under-sampled k-space data with least square data fitting. Experimental results have demonstrated that proposed approach exhibits excellent reconstruction performance. Moreover, if the image is full of similar low-dimensional-structures, proposed algorithm has dramatically improved Peak Signal to Noise Ratio (PSNR) 7～9 dB, with comparisons to other state-of-art compressive sampling methods.
基金by the JST CREST Program for novel carbon nanotube materialsThe XAS experiments were performed at BL25SU in SPring-8 with the approval of JASRT(Proposal No.2007B1732).
文摘Crystalline ErCl_(3) nanowires have been fabricated in single-walled carbon nanotubes(SWCNTs)with high yield(~90%),and the structural and magnetic properties of the resulting ErCl_(3) nanowires encapsulated in SWCNTs(ErCl_(3)@SWCNTs)characterized.Encapsulation under high temperature and vacuum using high quality SWCNTs results in a high fi lling-ratio of ErCl_(3) nanowires in the SWCNTs.The high fi lling-ratio of ErCl_(3) nanowires and the use of highly pure SWCNTs with only a small amount of residual Fe catalyst nanoparticles enabled us to observe the magnetic properties of ErCl_(3)@SWCNTs.Structure determination based on simulated annealing calculations and high-resolution transmission electron microscope(HRTEM)image simulations revealed that the structure of the ErCl_(3) nanowires is unusual with respect to the coordination environment of the Eu3+ions.This work opens up new possibilities to fabricate various metal complex nanowires with high yield and may also be of more general importance in understanding and exploring magnetic properties in low-dimensional magnetic systems.
基金Singapore Economic Development BoardEnergy Market Authority of Singapore+3 种基金National Research Foundation SingaporeNational University of SingaporeInternational Postdoctoral Exchange Fellowship Program(Talent-Introduction Program)of ChinaBoya Postdoctoral program of Peking University。
文摘Metal halide perovskites possess appealing optoelectronic properties and have been widely applied for solar energy harvesting and light emitting.Although perovskite solar cells(PeSCs)and perovskite light-emitting diodes(PeLEDs)have been developed rapidly in recent years,there are still no universal rules for the selection of perovskites to achieve high-performance optoelectronic devices.In this review,the working mechanisms of PeSCs and PeLEDs are first demonstrated with the discussion on the factors which determine the device performance.We then examine the optoelectronic properties of perovskites with structures modulated from 3D,2D,1D to 0D,and analyze the corresponding structure-property relationships in terms of photo-electric and electric-photo conversion processes.Based on the unique optoelectronic properties of structurally modulated perovskites,we put forward the concept of structural assembling engineering that integrate the merits of different types of perovskites within one matrix and elaborate their excellent properties for applications of both PeSCs and PeLEDs.Finally,we discuss the potential challenges and provide our perspectives on the structural assembling engineering of perovskites for future optoelectronic applications.
基金Supported by the Scientific Research Foundation of the Higher Education Institutions of Ningxia (No. NGY2017042)the National Natural Science Foundation of China (No. 21961027,21461020)+1 种基金the Natural Science Foundation of Ningxia (No. 2019AAC03071)the National First-rate Discipline Construction Project of Ningxia (Chemical Engineering and Technology)(NXYLXK2017A04)。
文摘Two new low-dimensional Mn(Ⅱ)coordination compounds of Mn(H2pimdc)2(phen)(compound 1)and[Mn(Hpimdc)(phen)]n·nH2O(compound 2)were synthesized,where H3pimdc is a 2-propyl-imidazole-4,5-dicarboxylic acid and phen is 1,10-phenanthroline.Both compounds were thoroughly analyzed by X-ray single-crystal diffraction,element analysis,IR spectra,PXRD and thermal analysis.X-ray single-crystal diffraction analyses indicate that the phen ligands terminate metal ions on two sides to prevent the linkage between the neighboring metal ions into a higher dimensional structure in compounds 1 and 2.Compound 1 is constructed from mononuclear molecules which form the 1D helical supramolecular chain by N-H···O hydrogen bonds.In compound 2,Hpimdc is a tetradentate bridging ligand,which binds Mn(Ⅱ)ions to generate a single-stranded right helical chain parallel to the b axis.These 1D chains are additionally coupled by H-bonds as well asπ···πstacking interactions,which formed a 3D supramolecular structure.Additionally,compound 2 demonstrated temperature-dependent magnetic susceptibility and negative value ofθ(equal to-9.09 K),which is indicative of weak antiferromagnetic interactions between Mn(Ⅱ)ions.
