Coordination Architectures Research Articles

Assembly of Three Cadmium(II) Complexes Based on Flexible α,ѡ-Bis(benzimidazolyl)alkane Ligands

Three flexible α,ѡ-bis(5,6-dimethylbenzimidazolyl)alkane ligands with different spacers were reacted with CdX2 (X = Cl, Br, I) hydrothermally, resulting in three coordination architectures, namely [CdI2(L1)]n (1), [CdBr2(L2)]n (2), and Cd2Cl4(L3)2 (3) [L1 = 1,3-bis(5,6- dimethylbenzimidazole)propane, L2 = 1,5-bis(5,6-dimethylbenzimidazole)pentane, L3 = 1,6- bis(5,6-dimethylbenzimidazole)hexane]. They have been characterized by elemental analyses, IR spectra, thermogravimetric (TG) analysis, and single-crystal X-ray diffraction. Complex 1displays a helical chain linked by the ligands L1, and a 2D supramolecular network is constructed through π-π stacking interactions; complex 2shows a helical chain structure with connections through two kinds of strong π-π stacking interactions into an intricate 3D supramolecular network; complex 3 contains dinuclear metallomacrocycles. The fluorescence properties of 1-3have been investigated in the solid state

Solvent-Dependent Formation of Cd(II) Coordination Polymers Based on a C2-Symmetric Tricarboxylate Linker

Three novel solvent-dependent Cd(II) coordination architectures [Cd3(BPT)2(DMF)2]·2H2O [1], [Cd3(BPT)2(DMA)2] [2], and [(CH3CH2)2NH2]·[Cd(BPT)]·2H2O [3] were obtained by the hydrothermal reaction of a C2-symmetric tricarboxylate linker, biphenyl-3,4′,5-tricarboxylic acid (H3BPT), with cadmium nitrate in the mixed solvents of water with N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMA), diethylformamide (DEF), respectively. Single-crystal X-ray diffraction analyses reveal that complex 1 is a three-dimensional (3D) network containing infinite Cd–O–Cd chains with the solvent DMF molecule bridging the neighboring Cd1 and Cd2 centers. Though complex 2 also has a 3D network containing infinite metal-carboxylate chains, the solvent DMA molecule only coordinates to one of the Cd(II) centers as a terminated solvent molecule. Complex 3 possesses a two-dimensional (2D) (6, 3) honeycomb type net formed by the mononuclear metal ion and the BPT ligand, which are further stacked in ABAB fashion through π–π intera...

Energetic transition metal (Co/Cu/Zn) imidazole perchlorate complexes: Synthesis, structural characterization, thermal behavior and non-isothermal kinetic analyses

On the reaction of imidazole (IMI) with transition metal perchlorates, three novel energetic coordination compounds, [Co(IMI)6](ClO4)2, [Cu(IMI)4](ClO4)2 and [Zn(IMI)4](ClO4)2, were obtained. They were characterized by elemental analysis, FT-IR spectroscopy and X-ray single crystal diffraction. Various fascinating coordination architectures of the central metals were found in these complexes. Co is coordinated by six IMI molecules and forms an octahedral structure. The Cu and Zn atoms are coordinated by four IMI molecules and construct rectangular and tetrahedral configurations, respectively. The thermal decomposition processes of these compounds were investigated through differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and FT-IR analyses. The kinetic parameters of the exothermic peaks of the compounds were calculated by applying five integral methods and one differential method, and the most probable kinetic mechanism functions for the compounds are the same and can be described as G(α)=1−(1−α)4, f(α)=1/4(1−α)−3.

Syntheses, characterization and crystal structure of d10 coordination architectures: From 1D to 3D complexes based on mixed ligands

Three coordination polymers, namely, [Zn2(ndd)2(2,2′-bpy)2·2H2O]n (1) [Cd(ndd)(2,2′-bpy)]n (2), and [Cd(ndd)(1,4-pyb)]n (3), where H2ndd=2,2′-(naphthalene-1,5-diylbis(oxy))diacetic acid, 1,4-pyb=1,4-bis(pyridin-4-ylmethoxy)benzene and 2,2′-bpy=2,2′-bipyridine, have been synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction analyses, powder X-ray diffraction and thermogravimetric analysis. Compound 1 can be considered as a 1D chain, which is further linked through the strongly multiple π–π interactions into a 3D supramolecular structure. By changing the metal ions, compound 2 is the 2D square structure (10.96×15.20Å) with the 44·62 topology. By changing the auxiliary ligand, compound 3 presents a new (4,5)-connected 3D network with the point symbol of (42·65·83)2·(66). Furthermore, compounds 1–3 show good fluorescence properties in the solid state at room temperature.

Metal–organic coordination architectures of condensed heterocyclic based 1,2,4-triazole: Syntheses, structures and emission properties

In efforts to explore the effects of metal ions, ligand structures, counteranions on the structures and properties of metal–organic complexes, seven d10 metals (Zn and Cd) and transition metals (Cu and Co) coordination compounds with condensed heterocyclic based 1,2,4-triazole 4,7-diphenyl-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazole (L1), 4-phenyl-7-(pyridine-3-yl)-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazole (L2), 4-phenyl-7-(pyridine-4-yl)-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazole (L3), and 4-(pyridine-3-yl)-7-(pyridine-4-yl)-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazole (L4), Zn(L1)2Cl2 (1), Co(L1)2Cl2 (2), {[Cd(L2)2(H2O)2]·(ClO4)2}∞ (3), Cd(L2)2(NO3)2(H2O)2 (4), {[Cu(L3)2(NO3)2]·(CH2Cl2)}∞ (5), {[Cu(L3)2(OH)(MeOH)]·(MeOH)2·BF4}∞ (6) and [Cd(L4)2(NO3)2]∞ (7) were synthesized and structurally characterized by elemental analyses, IR spectroscopy and single-crystal X-ray diffraction. Complexes 1, 2 and 4 have a mononuclear structure, 1 and 2 have similar structure, 3 and 6 have a neutral rhombohedral grid with a (4,4) topology, the coordination network of 3 further assembled into a three-dimensional framework by O–H⋯O hydrogen-bonding interactions, 5 reveals a coordination chain structures consisting of a neutral chain {[Cu(L3)2(NO3)2]·(CH2Cl2)}∞ with the CuII centers, and 7 has a coordination chain. Obviously, the structural differences among them are attributable to the difference of metal ions, counter-anions, the locality and amount of coordination atoms in ligands framework. All the complexes are air stable at room temperature. Furthermore, the fluorescent properties of complexes 1, 3, 4, 7 and corresponding ligands have been investigated and discussed.

Entangled Metal–Organic Frameworks of m-Phenylenediacrylate Modulated by Bis(pyridyl) Ligands

Solvothermal reactions of m-phenylenediacrylic acid (H2mpda) and zinc(II) salts in the presence of different bis(pyridyl) ancillary ligands afforded a series of supramolecular interpenetrated coordination architectures with formula [Zn(mpda)(bpee)]n (1), [Zn(mpda)(bpea)]n (2), and [Zn(mpda)(bpp)]n·2.5H2O (3) (bpee = 1,2-bis(4-pyridyl)ethylene, bpea = 1,2-bis(4-pyridyl)ethane, bpp = 1,3-bis(4-pyridyl)propane). X-ray analyses revealed that all of the compounds feature tetrahedral-based coordination geometry around Zn(II), two-dimensional (2D) 44 coordination networks with different linkers, and parallel 2D→2D interpenetration, which is stabilized by interlayer hydrogen-bonding interactions. The arc-shaped mpda ligand collaborates with quasi-linear bpee or bpea to generate 2D achiral networks with chair-shape windows in 1 and 2, but with two different arc-shaped ligands (mpda and bpp); the single network in 3 is homochiral and has boat-shaped windows. The different shapes of the networks result in different interpenetration modes. Both networks of 1 and 2 exhibit 3-fold parallel interpenetration and give trilayers. Differently, two layers of the same handedness in 3 interpenetrate to give a homochiral bilayer featuring double helical motifs, and the alternating stacking of oppositely handed bilayers renders the compound racemic. The interpenetration mode and the formation of the double helices in 3 benefit not only from the arc shape of the two bridging ligands but also from the match of the two ligands in length.

Assembly multi-dimensional CdII coordination architectures based on flexible bis(benzimidazole) ligands: Diversity of their coordination geometries and fluorescent properties

Based on three structurally related flexible bis(5,6-dimethylbenzimidazole) ligand, five novel metal–organic CdII coordination architectures: from 0D to 3D structures CdII complexes have been hydrothermally synthesized and structurally characterized, namely, Cd2I4(L1)2 (1), [CdCl2(L1)]n (2), [CdCl2(L2)]n (3), {[Cd(chdc)(L2)0.5]·H2O}n (4), {[Cd(pydca)(L3)0.5(H2O)2]·H2O}n (5) (where L1=1,2-bis(5,6-dimethylbenzimidazole)ethane, L2=1,3-bis(5,6-dimethylbenzimidazole)propane, L3=1,4-bis(5,6-dimethylbenzimidazole)butane, H2chdc=1,4-cyclohexanedicarboxylic acid, H2pydca=pyridine-2,6-dicarboxylic acid). A discrete binuclear [2+2] metallomacrocycles cadmium(II) complex of 1 is 0D, 3 and 5 exhibit one-dimensional helical and zigzag chain structures, respectively. 4 Forms a 2D layer with sql net topology bridged by carboxylate anion and L2, while 2 is an overall 3D array with the diamond topology (dia). In these complexes, the influences of anions coordination on the framework formation were observed and discussed. These results indicate the spacer length of the ligands and anions play important roles in controlling the diversity structural topologies of such metal–organic coordination architectures. The thermogravimetric analyses, X-ray powder diffraction and solid-state luminescent properties of the complexes have also been investigated.

Syntheses, Structures, and Photoluminescences of Four Cd(II) Coordination Architectures Based on 1-(4-Pyridylmethyl)-2-methylimidazole and Aromatic Carboxylates: From One-Dimensional Chain to Three-Dimensional Coordination Architecture

The use of 1-(4-pyridylmethyl)-2-methylimidazole (pmmid) combined with four kinds of benzenecarboxylic acid ligands has allowed the rational design of four novel Cd(II) coordination polymers (CPs), {[Cd(pmmid)(pa)(H2O)]·H2O}n (1), [Cd2(pmmid)2(cba)4] (2), [Cd1.5(pmmid)(tbba)3]n (3), and {[Cd(pmmid)(pma)0.5(H2O)]·5H2O}n (4), [H2pa = phthalic acid, Hcba = 4-chlorobenzoic acid, Htbba = 4-tert-butylbenzoic acid, and H4pma = pyromellitic acid], which were synthesized by reactions of Cd(OAc)2·2H2O and pmmid with aromatic acid under the ammoniacal condition and characterized by elemental analysis, infrared (IR) spectroscopy, powder X-ray diffraction (PXRD), and single crystal X-ray diffraction. Complex 1 possesses a one-dimensional (1D) chain architecture, complex 2 is an interesting 1D structure containing two kinds of 1D chains, complex 3 features a two-dimensional 63 topological network structure, and complex 4 is a novel three-dimensional coordination architecture framework containing a T4(2)10(2) water tape...

Construction of 1D and 2D Zinc Coordination Polymers Based on Organic Carboxylate Anions and Flexible Imidazole‐Containing Ligand

AbstractTwo novel zinc coordination polymers {[Zn(PhCOO)2(bmix)]}n 1 and {[Zn(ada)(bmix)]·(H2O)2}n 2 (bmix = 1,4‐bis(2‐methylimidazole‐1‐ylmethyl)benzene, H2ada = adipic acid), were obtained by the hydrothermal reactions of bmix and zinc acetate with two carboxylate anions, respectively. Structural analyses show that complex 1 possess a one‐dimensional helix chain structure, 2 takes two‐dimensional corrugated (4,4) layer motif. The structural differences of two complexes indicate that organic carboxylate anions play important roles in the formation of such zinc(II) coordination architectures.

A coordination architecture for UUV fleets

This paper presents a modular and expandable architecture, which includes diversified functions and can be applied to heterogeneous fleets of unmanned underwater vehicles (UUVs), to solve the problem of decentralized formation coordination. The architecture is modular and each module is built such that it can solve a precise task using one or more functions. Three functions among them play a key role for the whole architecture: localization, faultless formation control and fault tolerance. The localization function is performed by the use of an adaptive extended Kalman filter (A-EKF) algorithm; the fault-free formation control function is based on a nonlinear decentralized model predictive control (ND-MPC) algorithm; the fault tolerance function is based on a hierarchy graph theory. The novelty of the paper lies in the use of the above mentioned functions as the core of an architecture which is expandable, decentralized and can be applied to a wide range of vehicles.

A comparative study of coordination architectures constructed by di[4-(pyridin-3-yl)pyrimidinyl]disulfide and different metal salts: crystal structures and luminescence properties

Assembly of di[4-(pyridin-3-yl)pyrimidinyl]disulfide (3-ppds) with different metal salts resulted in a variety of coordination polymers that were structurally elucidated. For MnCl2, a 1-D repeated rhomboidal chain structure [MnCl2(3-ppds)2]n (1) was obtained, whereas a 1-D helical chain structure [Zn(NO3)2(3-ppds)]n (2) was built from Zn(NO3)2. A 1-D zigzag chain structure [Cu2(OAc)4(3-ppds)]n (3) was produced from Cu(OAc)2. In all three complexes, the 3-ppds ligand plays the same role as a bis(monodentate) bridging linker but with variations in both C–S–S–C torsion angles and dihedral angles defined by its conjugated heteroaromatic rings (pyrimidine and pyridine). The luminescence properties of the complexes have been evaluated in the solid state.

Metal coordination architectures of triazole-based ligands: Effect of the backbone of bridging ligands on the construction of polymers

In our efforts to investigate the influence of the backbone of different triazole-based bridging ligands on the structure of their metal complexes, four new coordination polymers, {[Cu(L1)2(H2O)2]Cl2}n (1), [Cu(L2)2Cl2]n (2), [Co(L2)2(SCN)2]n (3), and [Cu(L3)2(NO3)2]n (4), (L1 = 1,2-bis(triazol-1-ylmethyl)benzene, L2 = 1,3-bis(triazol-1-ylmethyl)benzene, L3 = 1,4-bis(triazol-1-ylmethyl)benzene), have been synthesized. All the complexes have been structurally characterized by IR, elemental analysis and single-crystal X-ray diffraction. Structural analyses show that 1 and 4 possess 2D coordination networks with (4,4) topology, and 1 shows a diagonal–diagonal inclined interpenetration. 2 and 3 are isostructural and feature 1D double chain, which further connected by C–H···Cl or π···π weak interactions to form 2D supramolecular frameworks. The results show that the structures of ligands (with different non-coordination backbone spacers) play important roles in the formation of such coordination architectures. Furthermore, EPR (Electron Paramagnetic Resonance) spectra of CuII complexes (1, 2, and 4) have been investigated in the solid state at room temperature.

Ionic radius-dependent self-assembly of closed/opened molecular capsules based on pentacyclopentanocucurbit[5]uril

Three coordination architectures, namely, {Ca2(H2O)4[(NO3)⊂Q*[5]]}2(NO3)6·26H2O (1), {Sr2(H2O)3(NO3)[(NO3)⊂Q*[5]]}(NO3)2·7H2O (2), {Ba(H2O)[(H2O)2 ⊂ Q*[5]]}–(NO3)2·11H2O (3), have been synthesized by reactions of the corresponding alkaline-earth metal salts with pentacyclopentanocucurbit[5]uril (Q*[5]). These compounds were characterized by single-crystal X-ray diffraction studies, showing that the ionic radius of the alkaline-earth metal plays a crucial role in determining which type of molecular capsule forms. Compound 1 is an incompletely closed molecular capsule, compound 2 corresponds to a closed molecular capsule, and compound 3 resembles an opened molecular capsule. The thermogravimetric analysis (TGA) of compound 2 was also characterized.

Two novel interpenetrating silver(i) coordination architectures modeled by semi-rigid tetra-pyridinate ligands

Two novel Ag(I) coordination polymers (CPs), namely, [Ag3(tpom)2(NO3)3(H2O)4]n (1) and [Ag2(tpom2)(NO3)2(H2O)4]n (2), (tpom = tetrakis(4-pyridyloxymethylene)methane, tpom2 = tetrakis(3-pyridyloxymethylene)methane) have been synthesized through the reaction of silver(I) nitrate and highly-connected tetra-pyridinate ligands and structurally characterized. Complex 1 exhibits the typical uninodal 3-connected four-fold interpenetrating layered hcb network with the point (Schläfli) symbol {63} considering the tetra-pyridinate tpom ligands as tri-connected nodes, but a 2-nodal 3,4-connected self-interpenetrating 3D network with stoichiometry (3-c)2(4-c)2 and the point (Schläfli) symbol {6 × 102}{62·104} considering the tetra-pyridinate tpom ligands as tetra-connected nodes. The difference between the two distinct topological structures mainly originates from the long Ag–N bond length of 2.513(3) Å in 1. In contrast, complex 2 exhibits the typical uninodal 4-connected four-fold interpenetrating 3D dia network with the point (Schläfli) symbol {66}. The flexible conformation and long connection arms of the different tetra-pyridiante ligands must be responsible for the variable interpenetrating Ag(I) coordination architectures. Additionally, results about TGA and photoluminescence spectra were also discussed.

Valence-induced assembly of CuI–CuII ions into different discrete coordination architectures by a disk-shaped polypyridyl ligand

The valences of metal ions were found to play key roles in controlling the formation and structures of discrete coordination architectures in a copper and disk-shaped hexa-monodentate ligand system. When Cu(I) and Cu(II) ions react with a polydentate ligand HPDQ, a hexanuclear "double-decker" like discrete "LM(3)M(3)L" coordination architecture (CuI)(6)(HPDQ)(2)(CHCl(3))(8) (complex 1), and a "LM(3)L + LM(3)" composite structure complex (Cu(NO(3))(2))(6)(HPDQ)(3) (complex 2) are formed, respectively.

Synthesis, characterization and structural transformation of a discrete tetragonal metalloprism

A novel M(2)L(4) tetragonal metalloprism, [(NO(3)(-))⊂{Cu(2)(μ-Hdpma)(4)}(NO(3))(2)](NO(3))(5) (1), was prepared from the self-assembly reaction of Cu(NO(3))(2)·3H(2)O and flexible clip-like organic ligand di(3-pyridylmethyl)amine (dpma) under acidic conditions. The cationic prismatic hollow structure of 1 hosts one nitrate anion via both metal-ligand dative bonds and electrostatic interactions. Metalloprism 1 can dissolve in water and its prismatic structure remains intact as supported by ESI-MS data. When metalloprism 1 was treated with sodium thiocyanate and sodium azide in aqueous solutions, two polymeric coordination architectures, [Cu(μ-Hdpma)(2)(NCS)(2)](NO(3))(2) (2) and [Cu(μ-dpma)(2)(μ-1,1-N(3))(μ-1,3-N(3))] (3), formed at room temperature, respectively. Polymer 2 has a two-dimensional sheet structure showing a simple rhombic 4(4)-sql topology in network connectivity, whereas polymer 3 gives a three-dimensional uninodal pcu net. The conformation of the flexible ditopic ligand is varied from a trans-trans-syn conformer in 1 to a trans-trans-anti conformer in 2 and to a trans-gauche-anti conformer in 3. The observations imply the occurrence of structural transformation from a discrete metalloprism into polymeric coordination architectures via a decoordination/rearrangement process. Magnetic studies of metalloprism 1 suggest that the two Cu(II) centers are weakly antiferromagnetically coupled. The spins communicate via the nitrate template while the Cu···O(nitrate) interactions are weak. For polymer 3, a ferromagnetically coupled system (J(2) = +17.6 cm(-1)) is operative between two Cu(II) centers bridged by end-on azidos and an antiferromagnetic coupling (J(1) = -7.7 cm(-1)) between two Cu(II) centers with end-to-end azidos. In contrast to relatively large coupling values of the reported examples, the weak ferromagnetic interaction results from insufficient spin delocalization between two Cu(II) centers.

Cadmium(II) and lanthanum(III) coordination architectures with anthracene-9,10-dicarboxylate: Crystal structures and photoluminescent properties

Two new coordination polymers, namely, [Cd(HL)2]∞ (1) and [La2(L)3(DMAC)6]∞ (2) (L=anthracene-9,10-dicarboxylate and DMAC=N,N-dimethylacetamide), were synthesized. Their structures were characterized by elemental analyses, infrared spectra, and single crystal X-ray diffraction analysis. Complex 1 is found to assume a three-dimensional (3D) twofold interpenetrating diamond network, showing one-dimensional channels running along the [111] direction. On the other hand, 2 has a two-dimensional 63 honeycomb network, which is further linked into 3D supramolecular networks by C–H···π interactions. The results indicate that the different synthesis methods play important roles in controlling the formation of the final frameworks of 1 and 2. The luminescent properties of the corresponding complexes were also briefly investigated.

A Multi-Agent System Architecture for Coordination of the Real-Time Control Functions in Complex Industrial Systems

Multi-agent system architecture for coordination of the real-time control functions in complex industrial systems is presented. The problem which must be solved out is how efficiently to organize the interactions between tasks in order to satisfy the functionality and the time restriction of the system. In order to solve this problem, the treatment of the task interactions is separated from the tasks and is implemented by the proposed multi-agent system. A general three level multi-agent system is introduced to manage the interactions and schedule of tasks. A framework of building of the schedule of the tasks is also presented. Finally, the benefits of the proposed architecture are discussed.

Policy‐driven customization of cross‐organizational features in distributed service systems

SUMMARYIn a cross‐organizational context, software services are provided and consumed by different organizations. Ensuring that the non‐functional requirements of all the involved organizations are satisfied is hard to achieve in such a distributed and heterogeneous environment: the implementation of features, for example, security, is scattered across the services of multiple organizations. In this paper, we present a coordination architecture for flexible and policy‐driven composition of cross‐organizational features in distributed service systems. The underlying approach of this architecture is to specify the features and their composition at a higher level that abstracts the internal implementation mechanisms of the organizations involved. By means of feature composition policies, the organizations specify at a fine‐grained level which features are required and when they have to apply. Driven by these policies, our coordination middleware dynamically integrates the appropriate features throughout the cross‐organizational service composition in a consistent and efficient way. We have validated our architecture in a proof of concept showing limited performance overhead. Copyright © 2011 John Wiley & Sons, Ltd.

A learning particle swarm optimization algorithm for odor source localization

This paper is concerned with the problem of odor source localization using multi-robot system. A learning particle swarm optimization algorithm, which can coordinate a multi-robot system to locate the odor source, is proposed. First, in order to develop the proposed algorithm, a source probability map for a robot is built and updated by using concentration magnitude information, wind information, and swarm information. Based on the source probability map, the new position of the robot can be generated. Second, a distributed coordination architecture, by which the proposed algorithm can run on the multi-robot system, is designed. Specifically, the proposed algorithm is used on the group level to generate a new position for the robot. A consensus algorithm is then adopted on the robot level in order to control the robot to move from the current position to the new position. Finally, the effectiveness of the proposed algorithm is illustrated for the odor source localization problem.