2D Grid Structure Research Articles

Two 2D Polyoxometalate‐Based Metal‐Organic Complexes Constructed from a New Flexible N‐Donor Ligand with High Capacitance Performances and Low Detection Limits of Cr(VI)

AbstractBy designing and using a new flexible bis(pyrimidine)‐bis(amide) ligand H2L [H2L=N,N′‐bis(4‐pyrimidinecarboxamido)‐1,3‐propane], two new polyoxometalate (POM)‐based metal‐organic complexes (MOCs), H3[Cu2(L)2(PMo12O40)] (1) and [Cu2(H2L)2(β‐Mo8O26)] (2), were synthesized under solvothermal and hydrothermal conditions, respectively. In complexes 1 and 2, metal‐organic units and POM anions are linked together to form two distinct 2D structures. The [PMo12O40]3− (PMo12) anions were used as μ4‐bridging ligands in complex 1 and linked the 1D [Cu(L)]n metal‐organic chains to form a 2D layered structure. The [β‐Mo8O26]4− (Mo8) anions adopted two diverse coordination modes in complex 2 and connected the 1D [Cu(H2L)]n2n+ metal‐organic chains to generate a 2D grid structure. Complexes 1–2 can serve as electrode materials of supercapacitor and show large specific capacitances, up to 1065 and 956 F g−1 at current density of 2 A g−1, respectively, which surpass the parent POM and most of the previous reported POM‐based electrode materials, thus demonstrating the important role of introducing metal‐organic units in improving capacitive performances. Besides, the electrocatalytic redox activities of complexes 1–2 were also studied, both of them can be used as electrochemical sensors to detect Cr(VI) ions. They possess high sensitivity of 0.537 and 0.455 μA μM−1 and low detection limits of 0.16 and 0.33 μM, which are below the maximum content of Cr(VI) in groundwater required by the WHO.

Study on the 3D BioPrinting Technology of Hydrogel Tissue Engineering scaffolds

The precision molding capability of bio-3D printing is the basis for its application in tissue engineering, and SA-Gel two-component hydrogel has been widely used in bio-3D printing manufacturing of tissue engineering scaffolds. The extrusionability of hydrogel is the key point for the printing precision. In this paper, starting from the concentration, ratio, rheology and cross-linking mode of hydrogel, the research ideas of “single factor independent analysis” and multi-factor comprehensive application are adopted to solve the printing accuracy. Through the research and screening of printing parameters and printing compensation technology, the accurate printing of the 1D line segment and 2D grid structure at 45°C for SA-Gel hydrogel with 2% and 8% mass respectively have been achieved.

Induction of 2D grid structure from amphiphilic pyrene assembly by charge transfer interaction

In this work, we report the spontaneous formation of 2-dimensional (2D) grid structures through charge transfer interactions of pyrene amphiphiles. Pure pyrene amphiphiles self-assemble into long nanofibers in aqueous solution. Remarkably, these aqueous nanofibers transform into a 2D grid structure upon charge transfer complexation. The charge transfer interaction induces crystallization of the aromatic core part, leading to discrete micelles with up and down hydrophilic chains, and hydrophobic side faces. Eventually, the anisotropic micelles grow in a 2-dimensional way through side-by-side interactions to form unusual 2D grid structures.

Nearest Neighbor Transformation of Quantum Circuits in 2D Architecture

In recent years, quantum computing has received extensive attention for its superior efficiency and application potential. For some physical architecture, one qubit can only interact with its adjacent qubits, SWAP gates are inserted to make a quantum circuit nearest neighbor compliant. The initial qubit placement algorithm in a 2D grid structure is proposed based on the constructed interaction cost metric model, and the method of dynamic grid decision is given. In order to obtain a better way of inserting SWAP gates, the gate level and circuit level interaction routing policies are put forward, and a heuristic pruning of interaction routing records is employed so as to reduce the runtime and additional quantum cost. Experimental results show that our proposed methods can achieve better performance than existing methods, and the average optimization rate of quantum cost is 21.76% and 17.23% respectively.

RUBIC: An Untethered Soft Robot With Discrete Path Following.

Soft robots have the potential to diminish the need for humans to venture into unsuitable environments or work in extreme conditions. While their soft nature gives them the advantage of being adaptable to changing environments, their control can be challenging because of the compliance that makes them effective. In this paper we present RUBIC: the Rolling, Untethered, Ballooning, Intelligent Cube, that overcomes some of the difficulties of 2D control by constraining motion to a discretised Cartesian space. RUBIC's method of locomotion is by rolling from one face of the cube to another, in any one of four directions. This motion causes it to move within a 2D grid structure, the dimensions of which are defined by the cube's characteristic length. When in its resting position RUBIC is inherently stable and forms a safe platform for tasks including taking measurements and soil samples, for localization and ad hoc network infrastructure, and as the foundation for larger robots and structures. We present the design of RUBIC's body, the four pneumatic ballooning actuators per face that generate its unique gait, and the control systems for locomotion and obstacle climbing. We consider constraints imposed by the design and fabrication methods including physical dimension and weight, material properties and control fidelity. An alternative locomotion scheme is proposed to improve the speed and linearity which also increases the distance traveled per roll. RUBIC travels with a mean locomotion accuracy of 4.58° deviation and successfully traverses steps up to 35% of its own height. The discretisation of a soft robotics workspace, as demonstrated by RUBIC, has advantages for safe and predictable locomotion and has applications in both structured and hazardous environments.

Three Cd(II) complexes based on pyridine containing mercapto-triazole and aromatic multi-carboxylates: Syntheses, structures and luminescent properties

Three new Cd(II) complexes, [Cd2(2-aptt)2(L1)(H2O)]n (1), {[Cd3(2-aptt)2(L2)2]·4H2O}n (2) and {[Cd3(2-aptt)2(L3)]·2H2O}n (3) [2-apttH = 4-amino-3-(2-pyridyl)-1H-1,2,4-triazoleq-5-thione, H2L1 = terephthalic acid, H2L2 = isophthalic acid, H4L3 = pyromellitic acid], have been synthesized under the same reaction condition but tuned by different aromatic multi-carboxylates. The X-ray single crystal diffraction analysis reveals that complexes 1–3 all display 2D architectures with different features depending on the spatial arrangements of coordinated ligands as well as their unlike coordination modes. The 2D architecture of 1 constructs from Cd(II)–aptt– layer structure and "wave-like" Cd(II)–L12– chains. Cd(II)–aptt– chains and Cd(II)–L22– chains connect each other to generate the 2D grid structure of 2. “Butterfly-like” Cd(II)–2-aptt– chains are distributed under or on the surface formed by Cd(II) and L34− anions, giving rise to the 2D framework of 3. Moreover, the thermal stabilities of complexes 1–3 were investigated. The luminescent properties of complexes 1–3 and the free ligand were also studied.

Enhanced electrochromic performance of 2D grid-structured WO3 thin films

Controlling the microstructure of Tungsten trioxide (WO3) film is believed to be an efficient strategy to enhance its electrochromic (EC) performance in recent years. Here, WO3 thin films with two-dimensional (2D) grid structure are fabricated through electrodeposition using polystyrene (PS) nanofibers as sacrificial templates. The surface of WO3 thin films has grooves formed by the removal of PS nanofibers and thus the films are divided into grid structure. Due to the larger specific surface area and lower diffusion impedance induced by the grid structure, these WO3 films demonstrate an obvious enhancement of EC performance compared with the plane WO3 thin films obtained using the same electrodeposition parameters in the absent of PS nanofibers templates. The transmittance modulation rate (ΔT) of the grid-structured WO3 thin films is over 50% larger than that of the plane WO3 films at the wavelength of 550 nm. Consequently, the grid-structured WO3 films have a higher coloration efficiency (71.8 cm2/C) compared with the plane WO3 films (58.8 cm2/C). Furthermore, the coloration/bleaching time of grid-structured WO3 films are 1.27/0.93 s, which is much shorter than the plane WO3 films (2.34/2.18 s). The grid-structured WO3 films in this work show potential applications in the construction of highly performance and rapidly responsive EC devices.

Construction of diverse dimensionality in eight coordination polymers of bivalent metal ions using 5-nitroisophthalate and different linear N,N′-donor linkers

Assembly of 5-nitroisophthalate (nip2−) with first row transition metal salts [Mn(II), Fe(II), Co(II), Zn(II)] in combination with the various neutral auxiliary N,N′-donor linkers, e.g., 2,5-bis-(4-pyridyl)-3,4-diaza-2,4-hexadiene (4-bpdh), 1,3-bis(4-pyridyl)propane (bpp) and 1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene (4-bpdb), yielded eight new coordination polymers (CPs), namely {[Mn(4-bpdh)(nip)(H2O)2]·H2O}n (1), {[Fe(4-bpdh)(nip)(H2O)2]·H2O}n (2), {[Co(4-bpdh)(nip)(H2O)2]·H2O}n (3), {[Mn2(bpp)2(nip)2(H2O)2]·H2O}n (4), {[Fe(bpp)(nip)(H2O)]·H2O}n (5), [Zn(bpp)(nip)(H2O)]n (6), {[Fe(4-bpdh)1.5(nip)]·(4-bpdh)0.5}n (7) and {[Fe(4-bpdb)(nip)]·(4-bpdb)0.5(H2O)}n (8) using the slow diffusion technique at room temperature. The complexes 1–8 were characterized by single crystal X-ray diffraction analysis and were further characterized by elemental analysis, infrared spectroscopy (IR) and powder X-ray diffraction (PXRD). Complexes 1–3 are isostructural and exhibit a one-dimensional (1D) metal-carboxylate chain with pendant 4-bpdh ligands, which is further extended into a three-dimensional supramolecular structure by means of H-bonding and π–π interactions. Complexes 4–6 are also isomorphous, but distinctly different from the first three complexes. They exhibit a similar 2-fold interpenetrated three-dimensional (3D) net with 66 dia net topology. Compound 7 displays a two-dimensional (2D) grid-like structure, having 4-bpdh ligands in the crystal void, and this is further extended by means of intermolecular π–π interactions into a 3D supramolecular structure, whereas compound 8 possesses a different 2D grid structure containing free 4-bpdb ligands in the void spaces. The thermal stabilities and UV–Vis spectra of all the complexes and the luminescent properties of complex 6 were also studied.

Sulfadiazine/dimethylsulfadiazine transition metal complexes: Synthesis, crystal structures and magnetic properties

Sulfadiazine (Hsulf) and dimethylsulfadiazine (Hdmsulf) were used to assemble divalent transition metal complexes (Cu, Ni or Co). Solvated complexes 1–4, dinuclear 1 (Cu2), tetranuclear 2 (Ni4) and 3 (Co4), and two-dimensional polymeric 4, were synthesized by controlling the metal ions, ligands and solvents. For complex 1, two Cu(II) ions are bridged by four NCN groups of four sulf− ligands, while for complex 2, four Ni(II) ions are alternatively bridged by the pyrimidine rings of four sulfadiazine ligands, forming a neutral square Ni4 molecule. In complex 3, four Co(II) ions are bridged by four μ3-OMe− groups, yielding a Co4O4 cubane. Complex 4 possesses a 2D grid structure with the Co(II) ions bridged by the remote amino groups of the ligand dmsulf−. Magnetic susceptibility measurements show that the desolvated complex (1d) exhibits antiferromagnetic coupling between adjacent Cu(II) ions with the 2J value of −90.0cm−1, and the pyrimidine rings transmit weak antiferromagnetic coupling in complex 2. Complex 3·8H2O shows ferromagnetic coupling via the methoxido bridges with the bridging CoOCo bond angles of 96–99°. Complex 4 displays a magnetic property for mononuclear cobalt(II) complexes due to the remote separation of Co(II) ions.

Syntheses, structures and properties of cobalt and manganese complexes based on pyridine-2,3,5,6-tetracarboxylic acid

Two new complexes based on pyridine-2,3,5,6-tetracarboxylic acid(H4pdtc) as ligand, {[Co2(pdtc)(H2O)4]·H2O}n (1) and {Mn2(pdtc)(H2O)4}n (2), have been obtained by hydrothermal syntheses and characterized by IR, elemental analysis, X-ray diffraction single crystal structure analysis, PXRD, thermal gravimetric analysis, and magnetic measurements. Complex 1 is 3D coordination polymer and complex 2 belongs to 2D grid structure by covalent bonds. In 1 and 2, the metal ions show antiferromagnetic interactions.

Dual Role for 1,2,4,5-Tetrazines in Polymer Networks: Combining Diels-Alder Reactions and Metal Coordination To Generate Functional Supramolecular Gels.

The inverse-electron demand Diels-Alder cycloaddition of tetrazines and olefins has emerged as a powerful coupling reaction for the formation of polymer gels with diverse applications. Tetrazines are also excellent ligands for metal atoms. For example, 3,6-bis(2-pyridyl)-1,2,4,5-tetrazines (bptz) have been used to generate discrete supramolecular Mxbptzy metal clusters and extended 2D grid structures. We reasoned that both the Diels-Alder and the metal-coordination modes of reactivity of bptz derivatives could be leveraged in the context of hydrogel design to yield novel hybrid materials. Here we report on the formation of supramolecular hydrogels via substoichiometric Diels-Alder functionalization of bptz ligands bound to the ends of poly(ethylene glycol) (PEG) chains followed by metal-coordination-induced gelation in the presence of Ni2+ and Fe2+ salts. Our results show that simple bptz-based polymers are versatile precursors to a diverse range of novel functional materials.

A non-regular layer arrangement of a pillared-layer coordination polymer: avoiding interpenetration via symmetry breaking at nodes.

A coordination terpolymerization strategy is introduced to alter the connectivity within layers of a pillared-layer coordination polymer. Assembling two different dicarboxylate linkers around a metal cluster in the layer suppresses interpenetration while enabling formation of a rectangular 2D grid structure.

Syntheses, structures and properties of silver(I) complexes constructed from nitrogenous aromatic heterocyclic carboxylic acids and N-donor ligands

Four new coordination complexes with silver(I) ions and nitrogenous aromatic heterocyclic carboxylic ligands, namely [Ag4(pztc)(phen)4]·8H2O (1), {[Ag4(pztc)(bpe)3]·5H2O}n (2), [Ag4(Hmptc)2(4,4′-bpy)3]·4.5H2O (3), and [Ag2(H2mptc)2(2,2′-bpy)2] (4) (H4pztc=pyrazine-2,3,5,6-tetracarboxylic acid, H3mptc=6-methyl-2,3,5-pyridine-tricarboxylic acid, phen=1,10-phenanthroline, bpe=trans-1,2-bis(4-pyridyl)ethylene, 4,4′-bpy=4,4′-bipyridine, 2,2′-bpy=2,2′-bipyridine), have been synthesized by the self-assembly reactions and characterized by X-ray diffraction single crystal structure analysis, elemental analysis, IR, PXRD, fluorescence and thermal analysis. In 1, four crystallographically independent silver(I) atoms are found to coordinate with only one pztc4− ligand. Complex 2 is a 2D grid structure. Complexes 3 and 4 are extended from 0D to 2D or 1D by the Ag⋯O interactions.

Flexible dicarboxylate based pillar-layer metal organic frameworks: differences in structure and porosity by tuning the pyridyl based N,N′ linkers

Dicarboxylate supported metal organic hybrids of Co(II), Zn(II) and Cd(II) have been synthesized using two different pyridyl based N,N′ linkers having Schiff base functionalized site. The use of flexible dicarboxylate glutarate in designing such frameworks has created a marked diversity in topology. The different N,N′ donor linkers also played an active part in the channel modification in the synthesized MOFs. The structural and topological diversity has been analyzed from the single crystal X-ray structure. Five compounds, {[Co(azpy)(glut)]·(CH3OH)}n (1), {[Co(meazpy)(glut)(H2O)2]·(H2O)3}n (2), {[Zn(azpy)0.5(glut)(H2O)]·(azpy)0.5}n (3), {[Zn(meazpy)0.5(glut)(H2O)]·(H2O)2}n (4) and {[Cd(azpy)(glut)]·(CH3OH)}n (5), show porous structures with solvent accessible voids. The nature of the pores as well as the existence of lattice solvent molecules in 1 and 2 are different due to the use of a different pillar ligand in their fabrication. In case of 3 and 4 there are some nice effects of non-covalent interaction in the construction of their solid state structure, which has also originated by the change of pillar N,N′ donor linkers. Complex 5 is topologically as well as structurally similar to 1 forming a 2D-grid like structure. In {[Cd2(meazpy)2(glut)(NO3)]2}n (6) there is a formation of 2D sheets with the coordinated counter anion. Interestingly, here the sheets are disposed in a perpendicular fashion to each other and do not contain any solvent accessible void. Upon removal of the solvent molecules, the frameworks 1–5 show moderate CO2 and H2 uptake at 273 K and 77 K, respectively. The desolvated frameworks show different quantities of CO2 and H2 uptake which has been corroborated to their structures.

Control of cultured human cells with femtosecond laser ablated patterns on steel and plastic surfaces

The purpose of the present study is to explore topographical patterns produced with femtosecond laser pulses as a means of controlling the behaviour of living human cells (U2OS) on stainless steel surfaces and on negative plastic imprints (polycarbonate). The results show that the patterns on both types of material strongly affect cell behaviour and are particularly powerful in controlling cell spreading/elongation, localization and orientation. Analysis by fluorescence and scanning electron microscopy shows that on periodic 1D grating structures, cells and cell nuclei are highly elongated and aligned, whereas on periodic 2D grid structures, cell spreading and shape is affected. The results also show that the density and morphology of the cells can be affected. This was observed particularly on pseudo-periodic, coral-like structures which clearly inhibited cell growth. The results suggest that these patterns could be used in a variety of applications among the fields of clinical research and implant design, as well as in diagnosis and in cell and drug research. Furthermore, this article highlights the noteworthy aspects and the unique strengths of the technique and proposes directions for further research.Electronic supplementary materialThe online version of this article (doi:10.1007/s10544-012-9726-8) contains supplementary material, which is available to authorized users.

유한요소법에서 희소행렬의 효율적인 저장을 위한 2차원 가변길이 벡터 저장구조

본 논문에서는 유한요소법에서 희소행렬의 효율적인 저장을 위한 2차원 가변길이 벡터 저장구조를 제안한다. 제안한 저장구조는 유한요소 전체 방정식의 거대희소행렬 <TEX>$N{\times}N$</TEX> 대신, 전체 행의 개수 N의 상삼각행렬에서 0이 아닌 실제 필요한 값들만 2차원 가변길이 벡터를 이용하여 저장하는 방법이다. 이 방법을 이용하면, 해석대상의 2차원 격자구조에서는 각 절점당 최소 1개에서 최대 5개까지의 저장 공간이 필요하게 되고, 3차원 격자구조에서는 각 절점당 최소 1개에서 최대 14개까지의 저장 공간이 필요하게 된다. 인덱스를 포함해도 2배 이상을 넘지 않는다. 본 논문의 실험 결과에 의해, 제안한 저장구조는 총 절점 개수가 많아질수록 기존의 최대칼럼 높이를 저장하는 스카이 라인 저장구조보다 메모리 공간을 효과적으로 줄일 수 있는 구조임을 알 수 있었다. In this paper, we propose the two dimensional variable-length vector storage format which can be used for efficient storage of sparse matrix in the FEM (finite element method). The proposed storage format is the method storing only actual needed non-zero values of each row on upper triangular matrix with the total rows N, by using two dimensional variable-length vector instead of <TEX>$N{\times}N$</TEX> large sparse matrix of entire equation of finite elements. This method only needs storage spaces of the number of minimum 1 to maximum 5 in 2D grid structure and the number of minimum 1 to maximum 14 in 3D grid structure of analysis target. The number doesn't excess two times although involving index number. From the experimental result, we can find out that the proposed storage format can reduce the memory space more effectively, as the total number of nodes increases, than the existing skyline storage format storing maximum column height.

Ferro/antiferromagnetic interactions transmitted by double bridged carboxylate groups in 2D mixed-ligand transition metal coordination polymers

Three 2D coordination polymers with mixed ligands [M(bpe)(bba)]n (M=Mn for 1, Co for 2 and Ni for 3, bpe=1,2-bis(4-pyridyl)ethane, H2bba=isophthalic acid) have been synthesized and characterized by single crystal X-ray diffraction, PXRD, TGA and magnetic susceptibility measurements. The central metal ions of each have a distorted octahedral geometry and are bridged by μ2-η1:η1 carboxylate groups to form binuclear units with metal–metal separations of 4.318Å (1), 4.463Å (2) and 4.551Å (3), respectively. The binuclear units are linked by bba2− to form 1D ribbons, which are further assembled through bpe ligands into a 2D grid structure. TGA analysis reveals that 1, 2, and 3 exhibit high thermal stability. The magnetic properties of 1, 2 and 3 were studied in the temperature range of 2–300K. Analysis of the magnetic data reveals antiferromagnetic interactions in 1 as well as interesting ferromagnetic interactions in 2 and 3 between the anti–syn double carboxylate groups bridging metal ions.

Sulfate binding in zinc(II) complexes of a monopyridylurea ligand N-(1-naphthyl)-N′-(3-pyridyl)urea

Abstract Two zinc(II) complexes of a urea-functionalized pyridyl ligand, [Zn(SO4)L3]·CH3OH ( 1 ) and {[Zn(μ2-SO4)L2]·0.5CH3OH}n ( 2 ) (L = N-(1-naphthyl)-N′-(3-pyridyl)urea), have been synthesized by the reaction of L with ZnSO4·7H2O under different conditions. Complex 1 is a hydrogen-bonded 2D grid structure in which the sulfate anion not only coordinates to the ZnII ion as a monodentate ligand but also forms multiple hydrogen bonds with the urea groups of adjacent molecules. In complex 2 the sulfate ion serves as a μ2-bridging ligand, connecting the ZnII ions to form an infinite 1D organic–inorganic hybrid framework. Meanwhile, the sulfate anion is also bound by neighboring ligands through hydrogen bonds between urea groups and the non-coordinated oxygen atoms. The solid-state emission spectra of 1 and 2 show a red shift of the fluorescence emission of ligand L.

2D Metallosupramolecular Arrays of Zinc‐5,10,15,20‐tetra(4‐pyridyl)porphyrin via Self‐complementary Coordination and Peripheral Linkage

AbstractA structural study on two isotypic infinite 2D metallosupramolecular arrays of Zinc‐5,10,15,20‐tetra(4‐pyridyl)porphyrin (ZnTPyP) has been undertaken. [ZnX2(μ3‐ZnTPyP)·3TCE]n (X = Cl, Br; TCE = 1,1,2,2‐tetrachloroethane) form extended 2D grid structures driven by self‐complementary axial coordination of the metalloporphyrin entities. They both crystallize in the monoclinic system, P21/c, Z = 4, a = 19.1176(15), b = 12.931(1), c = 21.8124(18) Å, β = 103.306(8)°, V = 5247.6(7) Å3 for X = Cl and a = 19.1644(7), b = 12.9984(5), c = 21.9013(9) Å, β = 103.141(4)°, V = 5312.9(4) Å3 for X = Br.

Three complexes based on ligands 1-hydroxybenzotriazole and 1,4-benzenedicarboxylic acid: Synthesis, structures and luminescence properties

Three new complexes, [Mn(OBt) 2(H 2O) 4]·3H 2O ( 1) (OBt = 1-hydroxybenzotriazole ion), [Zn 2(OBt) 2(BDC)(H 2O)·H 2O] n ( 2) (H 2BDC = 1,4-benzenedicarboxylic acid), and [Cu 3(OBt) 2(BDC)(μ 3-OH) 2(H 2O) 2·2H 2O] n ( 3) were synthesized by hydrothermal method and were characterized by elemental analysis, IR spectroscopy, TGA, XRPD, and single-crystal X-ray diffraction. The results from single-crystal X-ray diffraction indicate that 1, 2 and 3 are zero-dimensional (0D), two-dimensional (2D) and two-dimensional (2D) frameworks, respectively. In particular, there are all two crystallographically unique metal ions in the structures of complexes 2 and 3. Complex 2 possesses two helical chains in its structure. In the structure of 3, the chains that are built from tri-copper clusters and μ 3-O atoms are connected with BDC 2− to construct 2D grid structure. The luminescence properties of the three complexes were investigated.