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1.  A one-dimensional zigzag coordination polymer: catena-poly[[[triaqua­cadmium(II)]-[μ-2,2′-(5-methyl-1,3-phenyl­enedi­oxy)diacetato-κ4 O,O′:O′′,O′′′]] monohydrate] 
In the title one-dimensional coordination polymer, {[Cd(C11H10O6)(H2O)3]·H2O}n, the 2,2′-(5-methyl-1,3-phenyl­enedi­oxy)diacetate dianions connect CdII ions in a head-to-tail fashion to generate zigzag chains. The coordination geometry of the Cd atom is distorted penta­gonal bipyramidal. There are O—H⋯O hydrogen bonds between the carboxyl O atoms, the aqua ligands and the uncoordinated water mol­ecules.
PMCID: PMC2960183  PMID: 21201262
2.  Poly[diaqua­(μ-4,4′-bipyridine-κ2 N:N′)[μ-2,2′-(p-phenyl­enedi­oxy)diacetato-κ2 O:O′]cadmium] 
In the title compound, [Cd(C10H8O6)(C10H8N2)(H2O)2]n, the CdII ion has inversion symmetry and is coordinated by O atoms from two water mol­ecules and two bridging 2,2′-(μ-p-phenyl­enedi­oxy)diacetate ligands and two N atoms from two 4,4′-bipyridine ligands, giving a slightly distorted octa­hedral geometry. The diacetate and 4,4′-bipyridine ligands also lie across inversion centers. The bridging ligands form layers parallel to (11), with adjacent layers inter­connected via O—H⋯O hydrogen bonds between the coordinated water mol­ecules and the carboxyl­ate O atoms, giving a three-dimensional supra­molecular architecture.
PMCID: PMC3200682  PMID: 22058862
3.  catena-Poly[[aqua­bis­(pyridine-κN)copper(II)]-μ-2,2′-(p-phenyl­enedi­oxy)diacetato-κ2 O:O′] 
In the title compound, [Cu(C10H8O6)(C5H5N)2(H2O)]n, the Cu atom is five-coordinated by two O atoms from two carboxyl­ate groups of two different 2,2′-(p-phenyl­enedi­oxy)diacetate ligands, two N atoms from two pyridine mol­ecules and one water O atom. The geometry is square-pyramidal with the water O atom occupying the apical position. The carboxyl­ate group bridges adjacent Cu atoms, forming an infinite zigzag chain extending parallel to [001]. The chains are linked into layers by O—H⋯O hydrogen bonds. The Cu and water O atoms lie on special positions of site symmetry 2.
PMCID: PMC2983391  PMID: 21587426
4.  {2-[2-(Carb­oxy­meth­oxy)­phen­oxy]acetato}[2,2′-(o-phenyl­enedi­oxy)diacetic acid]sodium 4,4′-bipyridine hemisolvate monohydrate 
In the title compound, [Na(C10H9O6)(C10H10O6)]·0.5C10H8N2·H2O, the Na atom is eight-coordinated in an distorted dicapped-octa­hedral geometry by eight O atoms from a 2-(2-carb­oxy­meth­oxy­phen­oxy)acetate (o-BDOAH) anion and a 2,2′-(o-phenyl­enedi­oxy)diacetic acid (o-BDOAH2) mol­ecule. The uncoordinated 4,4′-bipyridine mol­ecule is arranged around an inversion center and exhibits rotational disorder. A three-dimensional supra­molecular network is built up in the crystal through O—H⋯O and O—H⋯N hydrogen bonds between the uncoordinated water mol­ecule, the uncoordinated 4,4′-bipyridine mol­ecule and the sodium complex mol­ecule.
PMCID: PMC3007220  PMID: 21588116
5.  Poly[[tetra­aqua­bis[μ4-2,2′-(p-phenyl­ene­di­oxy)diacetato][μ2-2,2′-(p-phenyl­ene­di­oxy)diacetato]dierbium(III)] hexa­hydrate] 
The asymmetric unit of the title compound, [Er2(C10H8O6)3(H2O)4]·6H2O, comprises one Er3+ ion, one and a half 2,2′-(p-phenyl­enedi­oxy)diacetate (hqda) ligands, two coordinated water mol­ecules and three uncoordinated water mol­ecules. The Er3+ ion is nine-coordinated by seven O atoms from hqda ligands and two O atoms from water mol­ecules. In the title compound, there are two types of crystallographically independent ligands: one with an inversion center in the middle of the ligand is chelating on both ends of the ligand towards each one Er center; the other hqda ligands are bridging-chelating on one side, and bridging on the other end of the ligand. Two adjacent Er3+ ions are thus chelated and bridged by –COO groups from hqda ligands in three coordination modes (briding–chelating, bridging and chelating). These building blocks are linked by OOC—CH2O—C6H4—OCH2—COO spacers, forming two-dimensional neutral layers. Adjacent layers are linked by O—H⋯O hydrogen-bonding inter­actions, forming a three-dimensional supermolecular network.
PMCID: PMC2971814  PMID: 21578590
6.  catena-Poly[(diaqua­cadmium)-μ-4,4′-[sulfonyl­bis­(1,4-phenyl­ene­oxy)]­di­acet­ato-κ4 O,O′:O′′,O′′′] 
In the title coordination polymer, [Cd(C16H12O8S)(H2O)2]n, the CdII ion is situated on a crystallographic twofold rotation axis, being coordinated by four O atoms from two bidentate 4,4′-[sulfonyl­bis­(1,4-phenyl­ene­oxy)]diacetate (L) ligands and two water mol­ecules in a highly distorted CdO6 octa­hedral geometry. Each complete ligand L, which is also generated by twofold symmetry with the S atom lying on the rotation axis, bridges two CdII atoms to form a polymeric zigzag chain propagating in the [10-1] direction. O—H⋯O hydrogen bonds between the coordinated water mol­ecules and carboxyl­ate O atoms are involved in the packing.
PMCID: PMC3297229  PMID: 22412419
7.  Poly[[diaqua­tris[μ4-(p-phenyl­enedi­oxy)diacetato]didysprosium(III)] dihydrate] 
The title dysprosium coordination polymer, {[Dy2(C10H8O6)3(H2O)2]·2H2O}n, was synthesized by reacting dysprosium(III) nitrate and the flexible ligand (p-phenyl­enedi­oxy)diacetic acid under hydro­thermal conditions. Each DyIII ion is coordinated by nine O atoms in a tricapped trigonal prismatic geometry. The DyO9 polyhedra form layers parallel to the bc plane. The rigid benzene rings of the anions link the layers along the a axis, forming a three-dimensional framework.
PMCID: PMC2961875  PMID: 21202796
8.  2,2′-(4,6-Dinitro-1,3-phenyl­enedi­oxy)diacetic acid dihydrate 
In the title compound, C10H8N2O10·2H2O, the skeleton of the dicarboxylic acid mol­ecule is approximately planar, the largest deviation being 0.477 (1) Å for an O atom of a nitro group; this nitro group is twisted out of the plane of the ring by 24.6 (1)°. Adjacent mol­ecules are linked by O—H⋯O hydrogen bonds, which connect the dicarboxylic acid and water mol­ecules into a three-dimensional supra­molecular network.
PMCID: PMC2971118  PMID: 21578350
9.  Diethyl 2,2′-(1,4-phenyl­enedi­oxy)­diacetate 
In the title compound, C14H18O6, a crystallographic center at the centroid of the aromatic ring generates the complete mol­ecule which is planar within 0.085 (1) Å for the non-H atoms. In the crystal, weak C—H⋯O and C—H⋯π inter­actions link the molecules.
PMCID: PMC3414340  PMID: 22904873
10.  catena-Poly[[di­aqua­[μ2-4-(4-carb­oxy­phen­oxy)benzoato](μ2-4,4′-oxydibenzo­ato)praseodymium(III)] monohydrate] 
In the title compound, {[Pr(C14H8O5)(C14H9O5)(H2O)2]·H2O}n, the PrIII cation is eight-coordinated by six carboxyl O atoms from both a monoanionic 4-(4-carb­oxy­phen­oxy)benzoate and a dianionic 4,4′-oxydibenzoate ligand (four bridging with two from a bidentate chelate inter­action), and two O-atom donors from water mol­ecules. A single water mol­ecule of solvation is also present. The complex units are linked through carboxyl O:O′ bridges giving a two-dimensional sheet polymer lying parallel to (001). An overall three-dimensional network structure is generated through inter­molecular carb­oxy­lic acid and water O—H⋯O hydrogen bonds and weak C—H⋯O inter­actions.
PMCID: PMC3884249  PMID: 24454025
11.  catena-Poly[[[bis­[μ-3-(4-carb­oxy­phen­oxy)propionato]-κ3 O 1,O 1′:O 1;κ3 O 1:O 1,O 1′-bis­[aqua­(N,N-dimethyl­formamide-κO)cadmium]]-μ-4,4′-bipyridine-κ2 N:N′] dinitrate] 
In the title coordination polymer, {[Cd2(C10H9O5)2(C10H8N2)2(C3H7NO)2(H2O)2](NO3)2}n, the 3-(4-carb­oxy­phen­oxy)propionate monoanion O,O′-chelates to a CdII cation through the aliphatic carboxyl­ate end. One of these O atoms is also connected to the metal cation from an inversion-related metal atom. The five O atoms bonded to the metal centre form a penta­gon, above and below which are located the N atoms of the 4,4′-bipyridine mol­ecules. The polycationic ribbon propagates along the b axis of the unit cell. The (aromatic) carboxyl end of the monoanion connects adjacent ribbons into a layer motif in the (102) plane. The nitrate ions are hydrogen bonded to the layer. The geometry of the CdII atom is a trans-N2O5Cd penta­gonal bipyramid.
PMCID: PMC3274930  PMID: 22346877
12.  catena-Poly[[diaqua­cadmium(II)]bis­(μ-2,2-dimethyl­butane­dioato-κ4 O,O′:O′′,O′′′)[diaqua­cadmium(II)]-μ-1,4-bis­(3-pyridylmeth­yl)piperazine-κ2 N 3:N 3′] 
In the title compound, [Cd2(C6H8O4)2(C16H20N4)(H2O)4]n, penta­gonal-bipyramidally coordinated CdII ions are connected into {Cd2(2,2-dimethyl­succinate)2(H2O)4} centrosymmetric dimeric clusters. In turn, these clusters are linked by tethering 1,4-bis­(3-pyridylmeth­yl)piperazine (3-bpmp) ligands into [Cd2(2,2-dimethyl­succinate)2(3-bpmp)(H2O)4]n coordination polymer chains. The chain motifs are oriented parallel to [10]. Individual chains are connected into supra­molecular layers via O—H⋯N and O—H⋯O hydrogen-bonding mechanisms.
PMCID: PMC2979442  PMID: 21579341
13.  Diacetato-κO;κ2 O,O′-aqua­(2,4,6-tri-2-pyridyl-1,3,5-triazine-κ3 N 2,N 1,N 6)manganese(II) monohydrate 
The MnII ion in the title compound, [Mn(CH3CO2)2(C18H12N6)(H2O)]·H2O, is seven-coordinated in an approximately penta­gonal–bipyramidal geometry by three N atoms of the tridentate 2,4,6-tri-2-pyridyl-1,3,5-triazine ligand and four O atoms from two distinct anionic acetato ligands and a water mol­ecule. One acetate anion chelates the Mn atom via two O atoms occupying equatorial positions, and the other anion coordinates the Mn atom as a monodentate ligand via one O atom. The complex and solvent water mol­ecules are linked by inter- and intra­molecular O—H⋯O, O—H⋯N and C—H⋯O hydrogen bonds into a three-dimensional network.
PMCID: PMC3200744  PMID: 22058860
14.  catena-Poly[[diaqua­(2,2′-bipyridine-κ2 N,N′)zinc]-μ-2,2′-[1,4-phenylene­bis(sulfanedi­yl)]diacetato-κ2 O:O′] 
In the polymeric title complex, [Zn(C10H8O4S2)(C10H8N2)(H2O)2]n, the Zn2+ ion lies on a twofold rotation axis and exhibits an octa­hedral environment, in which it is coordinated by two trans O atoms from two symmetry-related 2,2′-[1,4-phenyl­enebis(sulfanedi­yl)]diacetate anions, two N atoms from one 2,2′-bipyridine ligand, and two cis O atoms from water mol­ecules. The dihedral angle between the two pyridine rings is 11.5 (1)°. Adjacent Zn2+ ions are bridged in a monodentate manner by the diacetate anions, forming a chain structure extending parallel to [101], and are further linked into the final three-dimensional structure by O—H⋯O hydrogen bonds between the coordinating water mol­ecules as donor and the non-coordinating carboxyl­ate O atoms as acceptor atoms.
PMCID: PMC3274851  PMID: 22346798
15.  catena-Poly[[diaqua­cadmium(II)]-μ-4,4′-sulfonyl­dibenzoato-κ2 O 1:O 1′] 
The title compound, [Cd(C14H8O6S)(H2O)2]n, comprises zigzag chains parallel to [111] of alternating [Cd(H2O)2]2+ and sulfonyl­dibenzoate units, with the Cd and S atoms lying on crystallographic twofold axes. The central CdII ion is in a slightly distorted octa­hedral geometry, coordinated by six O atoms from two carboxyl­ate groups and two water O atoms. An intra­molecular C—H⋯O hydrogen bond occurs. In the crystal, inter­molecular hydrogen bonds between carboxyl­ate O atoms and coordinated water mol­ecules in adjacent chains lead to the formation of a three-dimensional network structure. The compound is isotypic with the Zn analog.
PMCID: PMC3009193  PMID: 21588837
16.  N,N′-Bis(4-methoxy­benzyl­idene)-4,4′-(m-phenyl­enedi­oxy)dianiline 
Mol­ecules of the title compound, C34H28N2O4, a Schiff base precursor for macrocycles, are located on a mirror plane. The C=N double bond is trans configured. Inter­molecular C—H⋯O inter­actions stabilize the crystal packing.
PMCID: PMC2968813  PMID: 21582603
17.  catena-Poly[(trans-diaqua­cadmium)-bis­{μ-5-[4-(1H-imidazol-1-yl)phen­yl]tetra­zol-1-ido}] 
In the title compound, [Cd(C10H7N6)2(H2O)2], the CdII atom lies on an inversion centre and is coordinated by four N atoms from 5-[4-(1H-imidazol-1-yl)phen­yl]tetra­zol-1-ide ligands and two O atoms from the coordinated water mol­ecules in an octa­hedral arrangement. The complex polymeric chains are inter­connected via inter­molecular water O—H⋯N hydrogen bonds into a three-dimensional network.
PMCID: PMC3344330  PMID: 22590096
18.  catena-Poly[[aqua­[1,4-bis­(1H-imidazol-4-yl)benzene]cadmium]-μ3-5-methyl­isophthalato] 
In the title coordination polymer, [Cd(C9H6O4)(C12H10N4)(H2O)]n, the CdII atom has a NO6 donor set and is coord­inated by five carboxyl­ate O atoms from three different 5-methyl-1,3-phenyl­enediacetate (pda2−) anions, one O atom from a water mol­ecule and one N atom from a 1,4-bis­(1H-imidazol-4-yl)benzene (L) ligand, displaying a highly distorted penta­gonal–bipyramidal geometry. Each pda2− anion acts as a μ3-bridge, linking CdII atoms to form one-dimensional slabs extending parallel to [010]. In the crystal, adjacent mol­ecules are linked through N—H⋯N and N—H⋯O hydrogen bonds into a three-dimensional network.
PMCID: PMC3200974  PMID: 22065019
19.  Poly[[di­aqua­[μ-1,4-bis(pyridin-4-ylmeth­yl)piperazine-κ2 N:N′]{μ-2,2′-[(1,4-phenyl­ene)bis(­oxy)]di­acetato-κ2 O:O′}cobalt(II)] penta­hydrate] 
In the title compound, {[Co(C10H8O6)(C16H20N4)(H2O)2]·5H2O}n, octa­hedrally coordinated CoII ions on crystallographic inversion centres are bound by trans O atoms belonging to two hydro­quinone-O,O′-di­acetate (hqda) anions {systematic name: 2,2′-[(1,4-phenyl­ene)bis­(­oxy)]di­acetate}, two trans-pyridine N-donor atoms from two bis­(pyridin-4-ylmeth­yl)piperazine (4-bpmp) ligands, and two trans aqua ligands. The exobidentate hqda and 4-bpmp ligands form [Co(hqda)(4-bpmp)(H2O)2]n coordination polymer layers parallel to (110) that are anchored into the full crystal structure by O—H⋯O hydrogen bonding between aqua ligands and ligated hqda O atoms. Disordered water mol­ecules of crystallization occupy incipient channels along [100]. However, these could not modeled reliably and so they were treated with SQUEEZE in PLATON [Spek (2009 ▶). Acta Cryst. D65, 148–155]; the crystal data take the presence of these mol­ecules into account. The crystal under investigation was twinned by non-merohedry, the twin fraction of the components being 53.3% and 46.7%. Only data from the major twin component were used in the refinement.
PMCID: PMC4051029  PMID: 24940193
20.  catena-Poly[[aqua­bis­(3-chloro­benzoato-κ2 O,O′)cadmium]-μ-N,N-di­ethyl­nico­tin­amide-κ2 N 1:O] 
In the crystal of the title CdII polymeric complex, [Cd(C7H4ClO2)2(C10H14N2O)(H2O)]n, the CdII cation is chelated by two chloro­benzoate anions and coordinated by two N,N-di­­ethyl­nicotinamide (DENA) ligands and one water mol­ecule in a distorted NO6 penta­gonal–bipyramidal geometry. The CdII cations are bridged by the pyridine N atom and carbonyl O atom of the DENA ligand to form a polymeric chain running along the b axis. Inter­molecular O—H⋯O hydrogen bonds between coordinating water mol­ecules and carboxyl­ate groups link adjacent chains into layers parallel to the bc plane. π–π contacts between benzene rings [shortest centroid–centroid distance = 3.912 (2) Å] further stabilizes the crystal structure. In the mol­ecule, weak C—H⋯O hydrogen bonds occur between the pyridine ring and carboxyl­ate groups; the dihedral angles between the carboxyl­ate groups and adjacent benzene rings are 4.6 (3) and 12.8 (3)°, while the benzene rings are oriented at a dihedral angle of 1.89 (13)°.
PMCID: PMC3793697  PMID: 24109284
21.  catena-Poly[diaqua­(cis-cyclo­hexane-1,2-dicarboxyl­ato)cadmium] 
In the title polymer, [Cd(C8H10O4)(H2O)2]n, the CdII cation is coordinated by five carboxyl­ate O atoms from three different cyclo­hexane-1,2-dicarboxyl­ate anions and two O atoms from two water mol­ecules, displaying a distorted CdO7 pentagonal–bipyramidal geometry. Each anion acts as a μ3-bridge, linking symmetry-related CdII ions into a layer parallel to (010). In the crystal, numerous O—H⋯O and C—H⋯O hydrogen bonds occur. The coordinated water mol­ecules and carboxyl­ate O atoms act as donors or acceptors in the formation of these hydrogen-bonding inter­actions.
PMCID: PMC3247538  PMID: 22219843
22.  Triaqua­bis{μ-N-[N-(4-meth­oxy-2-oxidobenzyl­idene)glyc­yl]glycinato(3−)}cadmium(II)dicopper(II) dihydrate 
In the title compound, [CdCu2(C12H11N2O5)2(H2O)3]·2H2O, the CuII atoms are in a square plane of N2O2 atoms contributed by the tetra­dentate Schiff base trianion. The CuII atoms are coordinated by one phenolate O atom, one imine N atom, one amido N atom and one carboxyl­ate O atom. The CdII atom is connected via the carboxyl­ate groups, forming a heterotrinuclear CuII–CdII–CuII system. The CdII atom is seven-coordinate in a penta­gonal-bipyramidal geometry with four O atoms from two carboxyl­ate groups and three aqua ligands. The heterotrinuclear mol­ecules are linked to the uncoordinated water mol­ecules by O—H⋯O hydrogen bonds into a three-dimensional framework.
PMCID: PMC2971383  PMID: 21578052
23.  Poly[[diaqua­[μ4-4,4′-carbonyl­bis(benzene-1,2-dicarboxyl­ato)]bis­(dipyrido[3,2-a:2′,3′-c]phenazine)dicadmium(II)] monohydrate] 
In the title compound, {[Cd2(C17H6O9)(C18H10N4)2(H2O)2]·H2O}n, the CdII atom is seven-coordinated by five O atoms from two different 4,4′-carbonyl­bis(benzene-1,2-dicarboxyl­ate) (BPTC) anions and one water mol­ecule, and by two N atoms from one chelating dipyrido[3,2-a:2′,3′-c]phenazine (L) ligand in a distorted penta­gonal-bipyramidal geometry. The BPTC anions link the CdII atoms, forming a one-dimensional chain structure. The L ligands are attached on both sides of the chain. A twofold rotation axis passes through the complex molecule. The crystal structure involves O—H⋯O hydrogen bonds.
PMCID: PMC2961587  PMID: 21202495
24.  Poly[[diaqua­nickel(II)]-μ2-4,4′-bipyridine-κ2 N:N′-μ-p-phenyl­enedioxy­diacetato-κ2 O:O′] 
The title coordination polymer, [Ni(C10H8O6)(C10H8N2)(H2O)2]n, was obtained by the hydro­thermal reaction of nickel(II) sulfate, benzene-1,4-dioxy­diacetic acid (p-phenyl­enedioxy­diacetic acid) and 4,4′-bipyridine (4,4′-bpy) in alkaline aqueous solution. Each NiII atom is coordinated by two O atoms from two benzene-1,4-dioxy­diacetate ligands, two N atoms from two 4,4′-bpy ligands and two water mol­ecules, and displays a distorted octa­hedral geometry. The NiII atom and benzene-1,4-dioxy­diacetate and 4,4′-bpy moieties lie on inversion centres. The benzene-1,4-dioxy­diacetate ligands bridge the NiII atoms to form infinite zigzag chains, which are further inter­connected by 4,4′-bpy ligands to form a grid-like layer parallel to the (01) plane. Moreover, there are O—H⋯O hydrogen-bonding inter­actions within the grid-like layer between the coordinated water mol­ecules and the carboxyl­ate O atoms.
PMCID: PMC2914940  PMID: 21200628
25.  Poly[di­ammonium [di­aqua­(μ7-benzene-1,2,3,4,5,6-hexa­carboxyl­ato)tetra­oxido­diuranium(VI)]] 
Uranyl-carboxyl­ate hybrid materials dominate the catalog of uranyl compounds owing in part to the affinity between COO− functional groups and UO2 2+. Polycarboxyl­ate organic ligands may present a degree of steric hindrance and could thus influence the resulting uranyl topology. Single crystals of the title compound, {(NH4)2[(UO2)2(C12O12)(H2O)2]}n, were synthesized hydro­thermally as a result of reacting uranyl nitrate with benzene-1,2,3,4,5,6-hexa­carb­oxy­lic acid (mellitic acid). The structure is comprised of a single unique monomeric uranyl cation adopting a penta­gonal bipyramidal geometry. The uranyl coordination sphere is composed of four O atoms originating from one half of a fully deprotonated mellitic acid ligand and a single water mol­ecule. The observed axial U—O bonds display an average distance of 1.765 (8) Å, whereas equatorial O atoms are found at an average distance of 2.40 (5) Å. All uranium–oxygen bond lengths are in good agreement with literature values. Furthermore, the coordin­ation between the uranyl penta­gonal bipyramids and the mellitic acid anion constructs a three-dimensional anionic framework which is charge-balanced with ammonium cations. Additional stabilization of the structure is provided by O—H⋯O and N—H⋯O hydrogen bonding inter­actions between the components.
PMCID: PMC3998547  PMID: 24826103

Results 1-25 (223031)