Metal Organic Coordination Architectures Research Articles

Important Counteranion Effect on Adsorption Efficacity of Hydrogen Sulfide by Silver(I)-Dithione Coordination Polymers.

Four new coordination polymers (CPs) have been prepared and evaluated for their efficacy in adsorbing hydrogen sulfide. The reactions of the structurally flexible assembling dithione ligand, L, with different silver(I) salts lead to four new metal-organic coordination architectures (CPs I, III, V, and VIII) exhibiting either one- or two-dimensional networks. CP I, 2D-[(Ag2Cl2)L]n, exhibits a linear series of rhomboid (S)2Ag(μ2-Cl)2Ag(S)2 secondary building units (SBUs) where S is one of the thione functions of L, altogether forming a 2D-network. CP III, 2D-[(AgI)L]n, is built upon parallel staircase-shaped 1D-[Ag2(μ3-I)2]n SBUs bridged by S atoms of L that form a 2D-grid. CP V, 2D-[(AgL)(NO3)]n, presents parallel 1D-folded S-shaped [AgL]n+ chains linked by strong argentophilic Ag···Ag interactions, forming a 2D-scaffolding. CP VIII, 1D-[(Ag2L3)(Cr2O7)]n, shows 1D-zigzag [{Ag(η2-μ2,η-μ,μ-L)}2]n2n+ chains accompanied by Cr2O72- counteranions. The adsorption isotherms of H2S gas by these new CPs were examined and compared to those of related CPs [(Ag2Br2)L]n (II), [(AgCN)4L]n (IV), [(Ag2L)(CF3SO3)2]n (VI), and [(Ag2L)(NO3)(ClO4)]n (VII). Among the tested polymers, the 3D-CP IV featuring cyanide anions exhibits the highest adsorption capacity of the CPs studied in this work. In order to determine the reason for this marked difference, density functional theory (DFT) computations were used. All in all, it turns out that the electrostatic interactions (CN-···H-SH) are significantly stronger than the O-···H-SH ones. This investigation provides a valuable conceptual tool for other designs of CPs and MOFs having the purpose of capturing toxic gases.

Metal–organic coordination architectures of tetrazole heterocycle ligands bearing acetate groups: Synthesis, characterization and magnetic properties

Two new coordination complexes with tetrazole heterocycle ligands bearing acetate groups, [Co(L)2]n (1) and [Co3(L)4(N3)2·2MeOH]n (2) (L=tetrazole-1-acetate) have been synthesized and structurally characterized. Single crystal structure analysis shows that the cobalt-complex 1 has the 3D 3,6-connected (42.6)2(44.62.88.10)-ant topology. By introducing azide in this system, complex 2 forms the 2D network containing the [Co3] units. And the magnetic properties of 1 and 2 have been studied.

Self-assembly of three new metal organic coordination networks based on 1,2-bis(imidazol-1yl-methyl)benzene

Three new metal organic coordination architectures from one-dimensional structures to three-dimensional frameworks, formulated as [Zn(μ-HCO2)(HCO2)(μ-o-bix)]n (1), {[Cu(μ-o-bix)2(H2O)2]·2HCO2}n (2) and {[Cd2(μ3-sip)2(μ-o-bix)2Cd(μ-o-bix)2(H2O)2]·5H2O} (3) (sip=5-sulfoisophthalate), were synthesized using the flexible 1,2-bis(imidazole-1-ylmethyl)-benzene (o-bix) ligand in mixed-solvent media (solvothermal conditions) and characterized by single-crystal diffraction, FT-IR and photoluminescence spectroscopy and thermogravimetric/differential thermal analysis. The X-ray crystallographic studies of 1 and 2 reveal 2D layer structures involving formate ions, which are generated in situ from the hydrolysis of DMF. Topological analysis results of the complexes show that 1 displays a honeycomb-like 63 layer and 2 has a hydrogen-bonded 2D structure with a 4-connected {44·62} square lattice topology. Compound 3 exhibits a 3D 4,6-connected tcj/hc {42·52·62}{42·56·64·73} net. In addition, the photoluminescence spectra of 1 and 3 show blue fluorescent emission bands; these emissions can probably be assigned to intraligand fluorescent emissions.

Influence of the counter anion and steric hindrance of pyrazolyl and imidazolyl flexible ligands on the structure of zinc-based coordination polymers

Treatments of flexible 1,4-bis(3,5-dimethylpyrazolyl)butane (bbd), 1,4-bis(imidazolyl)butane (bib) and 1,4-bis(2-methylimidazolyl)butane (bmib) ligands with zinc salts at room temperature, resulted in the formation of four novel metal–organic coordination architectures: [ZnI2(μ-bbd)]n (1), [Zn(NCS)2(μ-bbd)]n (2), {[Zn(μ-bib)2](ClO4)2·(Et2O)0.5·(H2O)0.25}n (3) and {[Zn(μ-bmib)2](ClO4)2·(H2O)4}n (4). X-ray crystallographic analyses show different 1D and 3D polymeric structures for compounds 1–4 due to the variation of the counter anions, solvent, steric hindrance and position of donating atoms in the structure of flexible ligands. In 1 and 2, one-dimensional (1D) zig-zag polymeric chains are formed via metal centers and μ-bbd ligands. Complex 3 shows a 3-fold interpenetrated 3D architecture with 103-ths network topology. In contrast to 3, in the structure of 4 neighboring Zn(II) ions are interconnected by a double-bridging μ-bmib ligands to form an infinite 1D polymeric double chain. The conformations of the flexible ligands were analyzed in detail.

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.

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 and characterization of nickel(ii) and cobalt(ii) coordination polymers based on 5-bromoisophthalate anion and bis(imidazole) ligands

Four new NiII and CoII complexes, [Ni(5-Br-ip)(bip)(H2O)]n (1), [Ni(5-Br-ip)(bib)]n (2), [Co(5-Br-ip)(bip)]n (3) and [Co(5-Br-ip)(bip)]n (4) (5-Br-H2ip = 5-bromoisophthalic acid, bip = 1,3-bis(imidazol)propane, bib = 1,4-bis(imidazol)butane), have been synthesized and structurally characterized by elemental analysis, IR and single-crystal X-ray diffraction. Complex 1 features a 2D double layer extended by the intermolecular hydrogen bonds between 2D layers. Complex 2 shows a 2-fold interpenetrating 3D → 3D network based on the dinuclear Ni(II) units. Complexes 3 and 4 can be regarded as supramolecular structural isomers. Isomer 3 possesses a 1D chain structure with binuclear Co units as subunits. Isomer 4 shows a 3D network and can be reduced to a 4-connected net with the (65.8) topology. The structural differences indicate that the backbone of the organic N-donor ligands and the nature of the metal ions play important roles in governing the structures of such metal–organic coordination architectures. Moreover, the magnetic properties of complexes 2 and 3 were also studied in 2–300 K.

Metal–organic coordination architectures of bis(1,2,4-triazole) ligands bearing different spacers: syntheses, structures and luminescent properties

In our continuous efforts to explore the effects of metal ions, ligands and counter anions on the structures and properties of metal–organic complexes, six transitional metal complexes with two structurally related ligands, 1,4-bis(1,2,4-triazol-1-ylmethyl)naphthalene (L1) and 4,4′-bis(1,2,4-triazol-1-ylmethyl)biphenyl (L2), [Cd(L1)2(NO3)2(H2O)]∞ (1), [Hg(L1)0.5(Br)2] (2), {[Mn(L1)2Cl2](H2O)8}∞ (3), {[Cu(L1)2Cl2](H2O)8}∞ (4), {[Cd(L2)2(CH3OH)2(NO3)2](H2O)}∞ (5) and [Cd(L2)3(CH3OH)2(ClO4)2(CHCl3)]∞ (6), were synthesized and structurally characterized. 1 has an infinite two-dimensional (2D) network structure and the 2D network further assembled into a 3D interpenetrating structure, 2 is a dinuclear structural molecule, 3 and 4 are neutral molecules with 1D chain structures and the same packing modes, and 5 and 6 have a similar structure, consisting of a 1D neutral coordination chain, but the coordination geometry around the CdII ion in 6 is different from that in 5. The results indicated that the structural differences among them are attributable to the difference of metal ions, counter-anions and ligands frameworks. All the complexes are air stable at room temperature. L1 and L2 adopt trans–gauche as well as gauche–gauche conformation with the shortest N⋯N distance between the two donors in all complexes. Furthermore, the fluorescent properties of complexes 1, 5, 6 and all ligands have been investigated and discussed.

Metal–organic coordination architectures of azole heterocycle ligands bearing acetic acid groups: Synthesis, structure and magnetic properties

Four new coordination complexes with azole heterocycle ligands bearing acetic acid groups, [Co( L 1 ) 2] n ( 1) , [Cu L 1 N 3] n ( 2), [Cu( L 2 ) 2·0.5C 2H 5OH·H 2O] n ( 3) and [Co( L 2 ) 2] n ( 4) (here, H L 1 =1H-imidazole-1-yl-acetic acid, H L 2 =1H-benzimidazole-1-yl-acetic acid) have been synthesized and structurally characterized. Single-crystal structure analysis shows that 3 and 4 are 2D complexes with 4 4-sql topologies, while another 2D complex 1 has a (4 3) 2(4 6)-kgd topology. And 2 is a 3D complex composed dinuclear μ 1,1-bridging azido Cu II entities with distorted rutile topology. The magnetic properties of 1 and 2 have been studied.

A series of 1-D to 3-D metal–organic coordination architectures assembled with V-shaped bis(pyridyl)thiadiazole under co-ligand intervention

Six new coordination polymers based on V-shaped linkage 2,5-bis(4-pyridyl)-1,3,4-thiadiazole (bpt) and transition metal ions, [Co(bpt)(pm) 0.5(H 2O)] n · 3 nH 2O ( 1), [Cu 2(bpt)(pm)(H 2O) 4] n ( 2), [Co(bpt)(pydc)] n · 2 nCHCl 3 · nH 2O ( 3), [Cu 2(bpt)(pydc) 2(H 2O) 2] n ( 4), [Cu 2(bpt)(pydco) 2(H 2O) 2] n · nH 2O ( 5) and [Cd(bpt)(pydco)] n ( 6) (H 4pm = pyromellitic acid, H 2pydc = pyridine-2,6-dicarboxylic acid, H 2pydco = pyridine-2,6-dicarboxylic acid N-oxide), have been synthesized under the intervention of various polycarboxylate ligands. Complex 1 exhibits a 3-D 4-connected structure with 1-D nanosized open channels encapsulated lots of water molecules. Complex 2 represents a 2-D grid containing two types of rectangular windows. When pydc and pydco instead of pm, complexes 3 and 6 were obtained with highly undulated 2-D layers. The interlayers of 3 are filled with two kinds of solvent molecules, whereas 6 is a double-layered framework without free molecules. Complexes 4 and 5 consist of two distinct 1-D infinite chains held together to form different 2-D supramolecular networks. Importantly, bpt spacer shows changeful conformational geometries and generates complicated crystalline architectures with the introduction of polycarboxylate ligands. Additionally, thermal stability of complexes 1, 3 and 5, fluorescent properties of 6 and X-ray powder diffraction of 1 have also been investigated.

D10 Metal complexes assembled from isomeric benzenedicarboxylates and 3-(2-pyridyl)pyrazole showing 1D chain structures: syntheses, structures and luminescent properties

Seven new d10 metal coordination polymers with isomeric benzenedicarboxylates and 3-(2-pyridyl)pyrazole ligands, [Zn2 L2(1,2-BDC)(H2O)]n ( 1), {[Cd2(H L)2(1,2-BDC)2] x H2O}n ( 2), [Cd(H L)(1,2-BDC)(H2O)]n (3), [Zn(H L)(1,3-BDC)(H2O) x 3H2O]n ( 4), [Cd2 L2(1,3-BDC)(H2O)]n (5), [Zn(H L)2(1,4-BDC)]n ( 6) and [Cd(H L)2(1,4-BDC)]n (7) (BDC = benzenedicarboxylate, H L = 3-(2-pyridyl)pyrazole), have been synthesized and structurally characterized by elemental analysis, IR and X-ray diffraction. Single-crystal X-ray analyses reveal that each complex takes a different one-dimensional (1D) chain structure. In 1-7, the BDCs act as bridging ligands, exhibiting rich coordination modes to link metal ions. The three BDC isomers exhibit different coordination modes: micro(1)-eta(1):eta(1)/micro(3)-eta(2):eta(1), micro(3)-eta(1):eta(2)/micro(3)-eta(2):eta(1), micro(2)-eta(1):eta(1)/micro(1)-eta(1):eta(0) and micro(1)-eta(1):eta(1)/micro(1)-eta(1):eta(0) for 1,2-BDC, micro(1)-eta(1):eta(1)/micro(1)-eta(1):eta(0) and micro(1)-eta(1):eta(0)/micro(2)-eta(2):eta(1) for 1,3-BDC, and micro(1)-eta(1):eta(0)/micro(1)-eta(0):eta(1), micro(1)-eta(1):eta(0)/micro(1)-eta(1):eta(0) and micro(1)-eta(1):eta(1)/micro(1)-eta(1):eta(1) for 1,4-BDC, respectively. In these complexes, H acts as a simple bidentate chelate ligand (in 2, 3, 4, 6 and 7), similar to 2,2'-bipyridine, or as a tridentate chelate-bridging ligand (in 1 and 5) via deprotonation of the pyrazolyl NH group and coordination of the pyrazolyl N atom to a second metal ion. The structural differences indicate that the backbone of such dicarboxylate ligands plays an important role in governing the structures of such metal-organic coordination architectures, and the chelating bipyridyl-like ligand H leads to the formation of these coordination polymers with one-dimensional structures by occupying the coordination sites of metal ions. Moreover, the photoluminescent properties of complexes were also studied in the solid-state at room temperature.

Metal–organic coordination architectures with 3-pyridin-3-yl-benzoate: crystal structures, fluorescent emission and magnetic properties

Reactions of 3-pyridin-3-yl-benzoic acid (HL) with metal nitrates under hydrothermal conditions yield seven new coordination polymers: Ni(L)2(H2O)2 (1), [Ni(L)2](H2O) (2), Co(L)2(H2O)2 (3), [Zn(L)2](H2O) (4), Cu(L)2 (5), Cd(L)2 (6) and Gd2(L)6(H2O)4 (7). A systematic investigation on coordination chemistry of the ligand and the significant function of supramolecular interactions in managing the resultant crystalline networks has been carried out. On the basis of the X-ray diffraction analysis of these complexes, the results show that complexes 1–5 and 7 form similar one-dimensional (1D) double-chain coordination arrays, among which 1 and 3, as well as 2 and 4, are isostructural. Remarkably, distinct network architectures are further constructed with the aid of weak secondary interactions. Amongst them, complexes 1, 3 and 5 exhibit the classical α-polonium networks, while complexes 2 and 4 present the (3,4)-connected two-dimensional layers. In 7, the intermolecular π–π stacking interactions lead to the formation of a double-strand structure. The CdII complex 6 assembles into a three-dimensional metal–organic framework exhibiting a unique 6-connected roa topology. The trans-configuration of L ligand is only found in the case of 6, whereas the cis-ligands are generally observed in these complexes. The fluorescent emission properties of 4 and 6 as well as the magnetic property of 7 have also been investigated.

Structural Diversity and Modulation of Coordination Architectures with Flexible Dithioether or Disulfoxide Ligands

AbstractMetal complexes of flexible dithioether and disulfoxide ligands are briefly reviewed, focusing on the structural investigations based on X‐ray crystallographic analyses. Recent investigations from our laboratory have produced compelling experimental evidence that flexible dithioether and disulfoxide ligands exhibit rich coordination chemistry towards metal ions and have great potential in constructing metal complexes with diverse structures. The design and synthesis of the ligands and their complexes are described. A wide variety of crystal structures of mononuclear, discrete multinuclear complexes and coordination polymers are classified by their assembling fashions, and the coordination modes of the two types of ligands are summarized. Series of structurally related ligands with varied spacer lengths or terminal groups were systematically used to coordinate the same metal ion in similar reaction conditions to afford complexes with different structures, indicating that the spacer lengths and terminal groups of ligands have important effects on the structures of the complexes. Using the same ligand to coordinate with different metal ions gave distinct complexes, showing the influences of the affinity and geometry of metal ions on the structures of the complexes. In addition, varying the anions, the solvent used, and the ratio of reactants in synthesis also led to the formation of complexes with different structures. These results present a feasible way to control the structures of complexes with these or other ditopic flexible ligands by modifying the ligands, selecting metal ions, as well as adjusting reaction conditions, which has been regarded as a long‐time challenge in engineering metal–organic coordination architectures. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

Synthesis, spectral and crystallographic characterization of manganese(II) coordination polymers based on aliphatic dicarboxylate and flexible bis(imidazolyl) derivatives

Two structurally related flexible imidazolyl ligands, bis( N-imidazolyl)methane (L 1) and 1,4-bis( N-imidazolyl)butane (L 2) reacted with Mn(II) salts of aliphatic dicarboxylic acids resulted in the formation of a number of novel metal-organic coordination architectures. All complexes have been structurally characterized by X-ray diffraction analysis. The different coordination modes of dicarboxylate anions due to their chain length, rigidity and diimidazolyl functionality lead to a range of different coordination structures. The coordination polymers exhibit 1D single chain, 2D sheet and 3D network structures. The aliphatic dicarboxylates can adopt chelating μ 2, bridging μ 2, and chelating–bridging μ 3 coordination modes, or act as uncoordinated counter anions. The central metal ions are coordinated in N 2O 4 and N 4O 2 fashions depending on the ancillary ligands. The topology of [Mn(male)(L 1)(H 2O) 2] ( 1, male = maleate) gives rise to singly bridged 1D chains, whereas compound [Mn(mal)(L 1)(H 2O)] · H 2O ( 2, mal = malonate) exhibits 2D sheets in which the metal centers are bridged by both imidazolyl ligands and dicarboxylates. Compounds [Mn(L 1) 2(H 2O) 2](suc) · 6H 2O ( 3, suc = succinate) and [Mn(L 1) 2(H 2O) 2](fum) · 6H 2O ( 4, fum = fumarate) show doubly bridged 1D chains, and the dicarboxylate groups are not coordinated but form 2D corrugated sheets with water molecules intercalated between the cationic layers. Compound [Mn(suc)(L 2)(H 2O) 2] ( 5, suc = succinate) was built from very flexible succinate and 1,4-bis( N-imidazolyl)butane which yielded three-dimensional interpenetrate networks, both succinate anion and the imidazolyl ligand act as bidentate bridging.

Metal–organic coordination architectures of 9,10-bis(N-benzimidazolyl)anthracene: syntheses, structures and emission properties

In our continuing efforts to investigate functional metal-organic coordination architectures, a benzimidazole-based rigid ligand, 9,10-bis(N-benzimidazolyl)anthracene (L), has been designed and used to react with CuI, AgI, CdII, MnII salts, giving rise to five new metal-organic coordination architectures, [CuLI]2·2CHCl3·H2O (1), [CdL2(NO3)2]·4C2H5OH (2), [AgL(BF4)]·3CHCl3 (3), [AgL(NO3)]·2CHCl3 (4) and [MnL2Cl2]·2CHCl3 (5), which were characterized by elemental analyses, IR spectroscopy, and X-ray crystallography. In 1, the CuI ion takes tetrahedral coordination geometry, and the rigid ligands bridge two dinuclear [Cu2I2] units to form a two-dimensional (2-D) layer. 2 and 5 show 2-D network structure with (4,4) topology in which the metal ions have octahedral coordination geometry. 3 and 4 display one-dimensional (1-D) chain structures, but show different crystal packing modes due to the effect of anions. These results indicate that the nature of ligand, metal coordination geometry and counter-anions have important effects on the structural topologies of such complexes. Furthermore, complexes 1–4 display strong blue emissions in solid state at room temperature.