A 2D coordination polymer built by sodium ion and water-soluble p-sulfonatothiacalix[4]arene of trivalent yttrium complex [Na(H2O)2Y(H2O)6(DMF) (p-sulfonatothiaca lix[4]arene)]-9H2O is reported. The complex be...A 2D coordination polymer built by sodium ion and water-soluble p-sulfonatothiacalix[4]arene of trivalent yttrium complex [Na(H2O)2Y(H2O)6(DMF) (p-sulfonatothiaca lix[4]arene)]-9H2O is reported. The complex belongs to the monoclinic system, space group P2 1/c, with a = 16.703(3), b = 17.819(4), c = 17.357(4)A, β = 106.23(3)°, Z = 4, V = 4960.0(17)A^3, Mr = 1304.08, Dc = 1.746 g/cm^3,μ= 1.624 mm^-1, F(000) = 2688, the final R = 0.0398 and wR = 0.1132 for 7534 observed reflections with I 〉 2σ(I). One yttrium(Ⅲ) ion is coordinated by the thiacalixarene ligand via the sulfonato group, and also ligated by an oxygen atom of a DMF molecule occupying the cavity of thiacalixarene and six aqua ligands.展开更多
A new 2D chiral cadmium coordination network [Cd(TCBA)2]?2EtOH (1) was prepared by the reaction of achiral angular asymmetric bridging ligand 2-((3,5-dimethyl- 4H-1,2,4-triazol-4-yl)-carbamoyl)-benzoic acid ...A new 2D chiral cadmium coordination network [Cd(TCBA)2]?2EtOH (1) was prepared by the reaction of achiral angular asymmetric bridging ligand 2-((3,5-dimethyl- 4H-1,2,4-triazol-4-yl)-carbamoyl)-benzoic acid (TCBA) with cadmium acetate, which was structurally characterized by IR, elemental analysis, thermogravimetric analysis and single-crystal X-ray diffraction. Complex 1 crystallizes in the chiral space group P21 and features a 2D chiral network consisting of two types of homo-chiral helices, which are further extended into a 3D chiral framework along the a-axis via hydrogen bonds. Moreover, powder second-order nonlinear optical (NLO) measurements reveal complex 1 has a modest second-harmonic-generation (SHG) efficiency at room temperature.展开更多
Very recently, the local coordination environment of active sites has been found to strongly influence their performance in electrocatalytic CO_(2) reduction by tuning the intrinsic kinetics of CO_(2) activation and i...Very recently, the local coordination environment of active sites has been found to strongly influence their performance in electrocatalytic CO_(2) reduction by tuning the intrinsic kinetics of CO_(2) activation and intermediate stabilization. It is imperative to elucidate the mechanism for such an influence towards the rational design of efficient catalysts;however, the complex interactions between the multiple factors involved in the system make it challenging to establish a clear structure–performance relationship. In this work, we chose ion-intercalated silver(I)-based coordination networks(AgCNs) with a well-defined structure as a model platform, which enables us to understand the regulation mechanism of counterions as the counterions are the only tuning factor involved in such a system. We prepared two isostructural Ag CNs with different intercalation ions or counterions of BF_(4)^(-) and ClO_(4)^(-)(named as AgCNs-BF_(4) and AgCNs-ClO_(4)) and found that the former has a more competitive CO_(2) electroreduction performance than the latter. AgCNs-BF_(4) achieves the highest Faradaic efficiency for CO_(2) to CO of 87.1% at-1.0 V(vs. RHE) with a higher partial current density, while AgCNs-ClO_(4) exhibits only 77.2% at the same applied potential.Spectroscopic characterizations and theoretical calculation reveal that the presence of BF_(4)^(-)is more favorable for stabilizing the COOH^(*) intermediate by weakening hydrogen bonds, which accounts for the superior activity of Ag CNs-BF_(4).展开更多
A major challenge of network virtualization is the virtual network resource allocation problem that deals with efficient mapping of virtual nodes and virtual links onto the substrate network resources. However, the ex...A major challenge of network virtualization is the virtual network resource allocation problem that deals with efficient mapping of virtual nodes and virtual links onto the substrate network resources. However, the existing algorithms are almost concentrated on the randomly small-scale network topology, which is not suitable for practical large-scale network environments, because more time is spent on traversing SN and VN, resulting in VN requests congestion. To address this problem, virtual network mapping algorithm is proposed for large-scale network based on small-world characteristic of complex network and network coordinate system. Compared our algorithm with algorithm D-ViNE, experimental results show that our algorithm improves the overall performance.展开更多
A new parameter coordination and robust optimization approach for multidisciplinary design is presented. Firstly, the constraints network model is established to support engineering change, coordination and optimizati...A new parameter coordination and robust optimization approach for multidisciplinary design is presented. Firstly, the constraints network model is established to support engineering change, coordination and optimization. In this model, interval boxes are adopted to describe the uncertainty of design parameters quantitatively to enhance the design robustness. Secondly, the parameter coordination method is presented to solve the constraints network model, monitor the potential conflicts due to engineering changes, and obtain the consistency solution space corresponding to the given product specifications. Finally, the robust parameter optimization model is established, and genetic arithmetic is used to obtain the robust optimization parameter. An example of bogie design is analyzed to show the scheme to be effective.展开更多
Training neural network to recognize targets needs a lot of samples.People usually get these samples in a non-systematic way,which can miss or overemphasize some target information.To improve this situation,a new meth...Training neural network to recognize targets needs a lot of samples.People usually get these samples in a non-systematic way,which can miss or overemphasize some target information.To improve this situation,a new method based on virtual model and invariant moments was proposed to generate training samples.The method was composed of the following steps:use computer and simulation software to build target object's virtual model and then simulate the environment,light condition,camera parameter,etc.;rotate the model by spin and nutation of inclination to get the image sequence by virtual camera;preprocess each image and transfer them into binary image;calculate the invariant moments for each image and get a vectors' sequence.The vectors' sequence which was proved to be complete became the training samples together with the target outputs.The simulated results showed that the proposed method could be used to recognize the real targets and improve the accuracy of target recognition effectively when the sampling interval was short enough and the circumstance simulation was close enough.展开更多
As two existing networks, the telecom network and the Internet differ greatly in terms of business patterns, service quality, security and regulations, whilst technical development makes services provided by the two n...As two existing networks, the telecom network and the Internet differ greatly in terms of business patterns, service quality, security and regulations, whilst technical development makes services provided by the two networks penetrate each other. This article describes the status quo of the telecom network and the Internet as well as the problems faced by each of them, analyzes the causes of those problems, and makes suggestions on coordinated and balanced development of the telecom network and the Internet.展开更多
In heterogeneous networks(Het Nets), it is desirable to offload users from macro cells to small cells to achieve load balancing. However, the offloaded users suffer a strong inter-tier interference. To guarantee the...In heterogeneous networks(Het Nets), it is desirable to offload users from macro cells to small cells to achieve load balancing. However, the offloaded users suffer a strong inter-tier interference. To guarantee the performance of the offloaded users, the interference from macro cells should be carefully managed. In this paper, we jointly optimize load balancing and interference coordination in multi-antenna Het Nets. Different from previous works, instead of almost blank subframes(ABS) on which the macro cells waste time resource, the macro cells suppress the interference to the offloaded users by zero-forcing beamforming(ZFBF) on interference nulling subframes(INS). Considering user association cannot be conduct frequently, we derive the long-term throughput of users over Rayleigh fading channels while previous works focused on instantaneous rate. From the perspective of the spectrum efficiency and user fairness, we formulate a long-term network-wide utility maximization problem. By decomposing the problem into two subproblems, we propose an efficient joint load balancing and interference coordination strategy. Simulation results show that our proposal can achieve good system performance gains over counterparts in term of the network utility, cell edge throughput and average throughput.展开更多
C_(2)H_(2)/CO_(2)separation is an industrially important process that remains challenging because of the similar physicochemical properties of C_(2)H_(2)and CO_(2).We herein report that the new square lattice(sql)coor...C_(2)H_(2)/CO_(2)separation is an industrially important process that remains challenging because of the similar physicochemical properties of C_(2)H_(2)and CO_(2).We herein report that the new square lattice(sql)coordination network[Cu(bipy‐xylene)2(NO3)2]n,sql‐16‐Cu‐NO3,16=bipy‐xylene=4,4′‐(2,5‐dimethyl‐1,4‐phenylene)dipyridine,exists in at least three forms,as‐synthesised(α),activated(α′)and hydrated(β).The activated phase,sql‐16‐Cu‐NO3‐α′,is an ultramicroporous material that exhibits high selectivity towards C_(2)H_(2)over CO_(2)as revealed by dynamic gas breakthrough experiments(1:1,C_(2)H_(2)/CO_(2))that afforded 99.87%pure CO_(2)in the effluent stream.The separation selectivity at 298 K and 1 bar,78,is the third best value yet reported for C_(2)H_(2)selective physisorbents whereas the mid‐loading performance sets a new benchmark.The performance of sql‐16‐Cu‐NO3‐α′is attributed to a new type of C_(2)H_(2)binding site in which CH···ONO2 interactions enable moderately strong sorbent‐sorbate binding(Qst(C_(2)H_(2))=38.6 kJ/mol)at low loading.Conversely,weak CO_(2)binding(Qst(CO_(2))=25.6 kJ/mol)at low loading means that(ΔQst)AC[Qst(C_(2)H_(2))–Qst(CO_(2))]is 13 kJ/mol at low coverage and 11.4 kJ/mol at mid‐loading.Analysis of in situ powder X‐ray diffraction and modelling experiments provide insight into the sorption properties and high C_(2)H_(2)/CO_(2)separation performance of sql‐16‐Cu‐NO3‐α′.展开更多
A new coordination compound [Mg(L)(H2 O)5·H2 O](NKU-109, H2 L=5-(4 H-1,2,4-triazol-4-yl)benzene-1,3-dicarboxylic acid) was solvothermally synthesized, featuring a supramolecular hydrogen-bonding network. ...A new coordination compound [Mg(L)(H2 O)5·H2 O](NKU-109, H2 L=5-(4 H-1,2,4-triazol-4-yl)benzene-1,3-dicarboxylic acid) was solvothermally synthesized, featuring a supramolecular hydrogen-bonding network. A good proton conductivity of 5.87×10^-4S/cm was recorded at 70℃ and a relative humidity of75% in alternating current(AC) impedance experiment, which sheds a new light on the design of proton conduction materials based on coordination compounds.展开更多
A new metal-organic framework based on ethyl 1H-tetrazole-5-acetate (Hetza), [Ag4(etza)4] (1), has been synthesized and characterized by elemental analysis, IR, thermal gravimetric and X-ray structural analysis....A new metal-organic framework based on ethyl 1H-tetrazole-5-acetate (Hetza), [Ag4(etza)4] (1), has been synthesized and characterized by elemental analysis, IR, thermal gravimetric and X-ray structural analysis. Crystal data for the title complex are as follows: triclinic system, space group P1 with a = 11.0771(6), b = 11.6636(6), c = 13.2925(8), a = 102.3710(10), β =103.3810(10), γ = 90.0890(10)°, V = 1629.60(16) A3, Mr = 1052.06, Z = 2, F(000) = 1024, Dc = 2.144 g/cm3, μ(MoKa) = 2.438 mm^-1, the final R = 0.0538 and wR = 0.1475 (I 〉 2σ(I)). Complex 1 adopts the (4.82) topological network and the alternately hydrophilic-hydrophilic and hydropho- bic-hydrophobic arrangements. The luminescent properties of complex 1 and the free Hetza ligand have been studied in the solid states.展开更多
Colon cancer is the third most common malignancy and the fourth most prevalent cause of death worldwide.Unfortunately,current cancer treatment approaches suffer from low specificity toward colon cancers and lack of fa...Colon cancer is the third most common malignancy and the fourth most prevalent cause of death worldwide.Unfortunately,current cancer treatment approaches suffer from low specificity toward colon cancers and lack of facile imagingmethod to monitor a real-time therapeutic process,usually resulting in severe toxicity to normal tissues.展开更多
We herein report the synthesis and metal-directed coordination self-assembly behaviors of three new macrocyc- lic azacalix[4]aromatics that comprise various numbers of pyridine and pyrazine rings bridged by N-CH3 grou...We herein report the synthesis and metal-directed coordination self-assembly behaviors of three new macrocyc- lic azacalix[4]aromatics that comprise various numbers of pyridine and pyrazine rings bridged by N-CH3 groups. Structural characterization of 1--3 explored that their conformations are fluxional in solution and each adopts a 1,3-alternate configuration in crystalline solids. The macrocyclic skeletons in azacalixaromatic 1--3 afford a good platform to designedly arrange coordination sites in a unique way relative to conventional multidentate ligands. Solid-state structures of three coordination self-assembled silver complexes (13--15) of 1 --3 determined by X-ray crystallography suggest that the nitrogen atoms on procumbent aromatics have better coordination ability than those on perpendicular aromatics and dictate the whole coordination self-assemblies. Unique discrete and 1D chain-like structures were thus obtained. This system may afford a deeper insight into the coordination self-assembly studies of heteroatom-bridged calixaromatics, possibly extending potential application of this novel macrocyclic polyden- tate organic compounds in the synthesis of functional metal organic framework formation.展开更多
A new metal-organic framework(MOF) based on metal clusters as secondary building units(SBU),has been synthesized and structurally characterized.The reported MOF presents an interesting 8-connected self-penetrating...A new metal-organic framework(MOF) based on metal clusters as secondary building units(SBU),has been synthesized and structurally characterized.The reported MOF presents an interesting 8-connected self-penetrating coordination network based on dinuclear cadmium cluster with a 4^(24)·5·6~3 topology. Moreover,the thermal stability and luminescence property of this compound have been investigated.展开更多
文摘A 2D coordination polymer built by sodium ion and water-soluble p-sulfonatothiacalix[4]arene of trivalent yttrium complex [Na(H2O)2Y(H2O)6(DMF) (p-sulfonatothiaca lix[4]arene)]-9H2O is reported. The complex belongs to the monoclinic system, space group P2 1/c, with a = 16.703(3), b = 17.819(4), c = 17.357(4)A, β = 106.23(3)°, Z = 4, V = 4960.0(17)A^3, Mr = 1304.08, Dc = 1.746 g/cm^3,μ= 1.624 mm^-1, F(000) = 2688, the final R = 0.0398 and wR = 0.1132 for 7534 observed reflections with I 〉 2σ(I). One yttrium(Ⅲ) ion is coordinated by the thiacalixarene ligand via the sulfonato group, and also ligated by an oxygen atom of a DMF molecule occupying the cavity of thiacalixarene and six aqua ligands.
基金supported by the National Natural Science Foundation of China(No.21201111,21401099 and 51204104)
文摘A new 2D chiral cadmium coordination network [Cd(TCBA)2]?2EtOH (1) was prepared by the reaction of achiral angular asymmetric bridging ligand 2-((3,5-dimethyl- 4H-1,2,4-triazol-4-yl)-carbamoyl)-benzoic acid (TCBA) with cadmium acetate, which was structurally characterized by IR, elemental analysis, thermogravimetric analysis and single-crystal X-ray diffraction. Complex 1 crystallizes in the chiral space group P21 and features a 2D chiral network consisting of two types of homo-chiral helices, which are further extended into a 3D chiral framework along the a-axis via hydrogen bonds. Moreover, powder second-order nonlinear optical (NLO) measurements reveal complex 1 has a modest second-harmonic-generation (SHG) efficiency at room temperature.
基金supported by financial support in part by NSFC (91961106, 51902253, 21725102)Anhui Provincial Natural Science Foundation (Grant 2108085MB46)+1 种基金Key Project of Youth Elite Support Plan in Universities of Anhui Province (Grant gxyqZD2021121)Shaanxi Provincial Natural Science Foundation (2020JQ-778)。
文摘Very recently, the local coordination environment of active sites has been found to strongly influence their performance in electrocatalytic CO_(2) reduction by tuning the intrinsic kinetics of CO_(2) activation and intermediate stabilization. It is imperative to elucidate the mechanism for such an influence towards the rational design of efficient catalysts;however, the complex interactions between the multiple factors involved in the system make it challenging to establish a clear structure–performance relationship. In this work, we chose ion-intercalated silver(I)-based coordination networks(AgCNs) with a well-defined structure as a model platform, which enables us to understand the regulation mechanism of counterions as the counterions are the only tuning factor involved in such a system. We prepared two isostructural Ag CNs with different intercalation ions or counterions of BF_(4)^(-) and ClO_(4)^(-)(named as AgCNs-BF_(4) and AgCNs-ClO_(4)) and found that the former has a more competitive CO_(2) electroreduction performance than the latter. AgCNs-BF_(4) achieves the highest Faradaic efficiency for CO_(2) to CO of 87.1% at-1.0 V(vs. RHE) with a higher partial current density, while AgCNs-ClO_(4) exhibits only 77.2% at the same applied potential.Spectroscopic characterizations and theoretical calculation reveal that the presence of BF_(4)^(-)is more favorable for stabilizing the COOH^(*) intermediate by weakening hydrogen bonds, which accounts for the superior activity of Ag CNs-BF_(4).
基金Sponsored by the Funds for Creative Research Groups of China(Grant No. 60821001)National Natural Science Foundation of China(Grant No.60973108 and 60902050)973 Project of China (Grant No.2007CB310703)
文摘A major challenge of network virtualization is the virtual network resource allocation problem that deals with efficient mapping of virtual nodes and virtual links onto the substrate network resources. However, the existing algorithms are almost concentrated on the randomly small-scale network topology, which is not suitable for practical large-scale network environments, because more time is spent on traversing SN and VN, resulting in VN requests congestion. To address this problem, virtual network mapping algorithm is proposed for large-scale network based on small-world characteristic of complex network and network coordinate system. Compared our algorithm with algorithm D-ViNE, experimental results show that our algorithm improves the overall performance.
基金This project is supported by National Natural Science Foundation of China (No.60304015, No.50575142).
文摘A new parameter coordination and robust optimization approach for multidisciplinary design is presented. Firstly, the constraints network model is established to support engineering change, coordination and optimization. In this model, interval boxes are adopted to describe the uncertainty of design parameters quantitatively to enhance the design robustness. Secondly, the parameter coordination method is presented to solve the constraints network model, monitor the potential conflicts due to engineering changes, and obtain the consistency solution space corresponding to the given product specifications. Finally, the robust parameter optimization model is established, and genetic arithmetic is used to obtain the robust optimization parameter. An example of bogie design is analyzed to show the scheme to be effective.
基金Supported by the Ministerial Level Research Foundation(404040401)
文摘Training neural network to recognize targets needs a lot of samples.People usually get these samples in a non-systematic way,which can miss or overemphasize some target information.To improve this situation,a new method based on virtual model and invariant moments was proposed to generate training samples.The method was composed of the following steps:use computer and simulation software to build target object's virtual model and then simulate the environment,light condition,camera parameter,etc.;rotate the model by spin and nutation of inclination to get the image sequence by virtual camera;preprocess each image and transfer them into binary image;calculate the invariant moments for each image and get a vectors' sequence.The vectors' sequence which was proved to be complete became the training samples together with the target outputs.The simulated results showed that the proposed method could be used to recognize the real targets and improve the accuracy of target recognition effectively when the sampling interval was short enough and the circumstance simulation was close enough.
文摘As two existing networks, the telecom network and the Internet differ greatly in terms of business patterns, service quality, security and regulations, whilst technical development makes services provided by the two networks penetrate each other. This article describes the status quo of the telecom network and the Internet as well as the problems faced by each of them, analyzes the causes of those problems, and makes suggestions on coordinated and balanced development of the telecom network and the Internet.
基金supported by the National Natural Science Foundation of China (61672484)the National Hi-Tech Research and Development Program of China (2014AA01A702)
文摘In heterogeneous networks(Het Nets), it is desirable to offload users from macro cells to small cells to achieve load balancing. However, the offloaded users suffer a strong inter-tier interference. To guarantee the performance of the offloaded users, the interference from macro cells should be carefully managed. In this paper, we jointly optimize load balancing and interference coordination in multi-antenna Het Nets. Different from previous works, instead of almost blank subframes(ABS) on which the macro cells waste time resource, the macro cells suppress the interference to the offloaded users by zero-forcing beamforming(ZFBF) on interference nulling subframes(INS). Considering user association cannot be conduct frequently, we derive the long-term throughput of users over Rayleigh fading channels while previous works focused on instantaneous rate. From the perspective of the spectrum efficiency and user fairness, we formulate a long-term network-wide utility maximization problem. By decomposing the problem into two subproblems, we propose an efficient joint load balancing and interference coordination strategy. Simulation results show that our proposal can achieve good system performance gains over counterparts in term of the network utility, cell edge throughput and average throughput.
基金Science Foundation Ireland,Grant/Award Numbers:13/RP/B2549,16/IA/4624Japan Society for the Promotion of Science,Grant/Award Numbers:JP18H05262,JP19K15584Irish Research Council,Grant/Award Number:IRCLA/2019/167。
文摘C_(2)H_(2)/CO_(2)separation is an industrially important process that remains challenging because of the similar physicochemical properties of C_(2)H_(2)and CO_(2).We herein report that the new square lattice(sql)coordination network[Cu(bipy‐xylene)2(NO3)2]n,sql‐16‐Cu‐NO3,16=bipy‐xylene=4,4′‐(2,5‐dimethyl‐1,4‐phenylene)dipyridine,exists in at least three forms,as‐synthesised(α),activated(α′)and hydrated(β).The activated phase,sql‐16‐Cu‐NO3‐α′,is an ultramicroporous material that exhibits high selectivity towards C_(2)H_(2)over CO_(2)as revealed by dynamic gas breakthrough experiments(1:1,C_(2)H_(2)/CO_(2))that afforded 99.87%pure CO_(2)in the effluent stream.The separation selectivity at 298 K and 1 bar,78,is the third best value yet reported for C_(2)H_(2)selective physisorbents whereas the mid‐loading performance sets a new benchmark.The performance of sql‐16‐Cu‐NO3‐α′is attributed to a new type of C_(2)H_(2)binding site in which CH···ONO2 interactions enable moderately strong sorbent‐sorbate binding(Qst(C_(2)H_(2))=38.6 kJ/mol)at low loading.Conversely,weak CO_(2)binding(Qst(CO_(2))=25.6 kJ/mol)at low loading means that(ΔQst)AC[Qst(C_(2)H_(2))–Qst(CO_(2))]is 13 kJ/mol at low coverage and 11.4 kJ/mol at mid‐loading.Analysis of in situ powder X‐ray diffraction and modelling experiments provide insight into the sorption properties and high C_(2)H_(2)/CO_(2)separation performance of sql‐16‐Cu‐NO3‐α′.
基金supported by the 973 Program of China (No. 2014CB845600)the National Natural Science Foundation of China (Nos. 21421001 and 21531005)the Natural Science Foundation of Tianjin(No. 15JCZDJC38800)
文摘A new coordination compound [Mg(L)(H2 O)5·H2 O](NKU-109, H2 L=5-(4 H-1,2,4-triazol-4-yl)benzene-1,3-dicarboxylic acid) was solvothermally synthesized, featuring a supramolecular hydrogen-bonding network. A good proton conductivity of 5.87×10^-4S/cm was recorded at 70℃ and a relative humidity of75% in alternating current(AC) impedance experiment, which sheds a new light on the design of proton conduction materials based on coordination compounds.
基金supported by National Natural Science Foundation of China(21401147)Basic Research Program of Natural Science from Shaanxi Provincial Government(2015JQ2032)+2 种基金Scientific Research Program from Education Department of Shaanxi Provincial Government(2013JK0654)Opening Foundation from State Key Laboratory of Coordination Chemistry in Nanjing University(201219)and the Program for Distinguished Young Scholars of Xi’an Polythenic University(201403)
文摘A new metal-organic framework based on ethyl 1H-tetrazole-5-acetate (Hetza), [Ag4(etza)4] (1), has been synthesized and characterized by elemental analysis, IR, thermal gravimetric and X-ray structural analysis. Crystal data for the title complex are as follows: triclinic system, space group P1 with a = 11.0771(6), b = 11.6636(6), c = 13.2925(8), a = 102.3710(10), β =103.3810(10), γ = 90.0890(10)°, V = 1629.60(16) A3, Mr = 1052.06, Z = 2, F(000) = 1024, Dc = 2.144 g/cm3, μ(MoKa) = 2.438 mm^-1, the final R = 0.0538 and wR = 0.1475 (I 〉 2σ(I)). Complex 1 adopts the (4.82) topological network and the alternately hydrophilic-hydrophilic and hydropho- bic-hydrophobic arrangements. The luminescent properties of complex 1 and the free Hetza ligand have been studied in the solid states.
基金supported by the National Key R&D Program of China(no.2019YFA0210103)the National Natural Science Foundation of China(grant nos.51872088,21804039,21977027,21890744,and 21890744)the Fundamental Research Funds for the Central Universities.
文摘Colon cancer is the third most common malignancy and the fourth most prevalent cause of death worldwide.Unfortunately,current cancer treatment approaches suffer from low specificity toward colon cancers and lack of facile imagingmethod to monitor a real-time therapeutic process,usually resulting in severe toxicity to normal tissues.
基金Financial support by the National Natural Science Foundation of China,the National Basic Research Program of China (973 program,2011CB932501 and 2013CB834501) is gratefully acknowledged.This work is also supported by Tsinghua University Initiative Scientific Research Program
文摘We herein report the synthesis and metal-directed coordination self-assembly behaviors of three new macrocyc- lic azacalix[4]aromatics that comprise various numbers of pyridine and pyrazine rings bridged by N-CH3 groups. Structural characterization of 1--3 explored that their conformations are fluxional in solution and each adopts a 1,3-alternate configuration in crystalline solids. The macrocyclic skeletons in azacalixaromatic 1--3 afford a good platform to designedly arrange coordination sites in a unique way relative to conventional multidentate ligands. Solid-state structures of three coordination self-assembled silver complexes (13--15) of 1 --3 determined by X-ray crystallography suggest that the nitrogen atoms on procumbent aromatics have better coordination ability than those on perpendicular aromatics and dictate the whole coordination self-assemblies. Unique discrete and 1D chain-like structures were thus obtained. This system may afford a deeper insight into the coordination self-assembly studies of heteroatom-bridged calixaromatics, possibly extending potential application of this novel macrocyclic polyden- tate organic compounds in the synthesis of functional metal organic framework formation.
基金supported by the National Science Foundation of China(No.51073079)the Natural Science Fund of Tianjin,China (No.10JCZDJC22100)the Fundamental Research Funds for the Central Universities
文摘A new metal-organic framework(MOF) based on metal clusters as secondary building units(SBU),has been synthesized and structurally characterized.The reported MOF presents an interesting 8-connected self-penetrating coordination network based on dinuclear cadmium cluster with a 4^(24)·5·6~3 topology. Moreover,the thermal stability and luminescence property of this compound have been investigated.