A new three‐dimensional cobalt(II) coordination polymer with a 4‐connected CdSO4‐like topology

The title cobalt(II) coordination polymer, poly[[diaquacobalt(II)]‐μ₄‐3,3′‐(p‐phenylene)diacrylato], [Co(C₁₂H₈O₄)(H₂O)₂]_n, was obtained by reaction of Co(NO₃)₂·6H₂O and 3,3′‐(p‐phenylene)diacrylic acid (H₂L) under hydrothermal conditions. Each Co^II cation sits on a centre of inversion and is hexacoordinated by six O‐atom donors in an octahedral geometry. The Co^II centres are connected by four centrosymmetric L²⁻ anions, resulting in a three‐dimensional framework structure. The coordinated water molecules and carboxylate O atoms form hydrogen‐bond interactions, stabilizing the structure of the three‐dimensional framework. Topologically, the framework represents a rare example of the three‐dimensional 4‐connected CdSO₄ network type. The metal cations and the organic ligand both show in‐plane coordination with respect to the extended structure.     

The one‐dimensional chain polymer of aqua(tyrosinato)zinc(II)

In the title compound, catena‐poly[[aquazinc(II)]‐μ₃‐tyrosinato], [Zn(C₉H₇NO₃)(H₂O)]_n, each Zn atom has a distorted square‐pyramidal geometry comprised of three O atoms and one N atom from three tyrosinate (tyr) ligands, and one aqua ligand. Two inversion‐related Zn²⁺ ions are bridged by two O atoms from the phenolate groups of two tyr ligands to form a centrosymmetric dimeric unit, which can be described as a planar Zn₂O₂ four‐membered ring. These repeating dimeric units are arranged along the c axis to give a one‐dimensional chain coordination polymer, in which the tyr ligand adopts an unusual chelating/bridging coordination mode.     

Two threefold interpenetrated two‐dimensional frameworks based on a flexible imidazole‐containing ligand and benzene‐1,4‐dicarboxylate

The open‐chain polyether‐bridged flexible ligand 1,2‐bis[2‐(1H‐1,3‐imidazol‐1‐ylmethyl)phenoxy]ethane (L) has been used to create two two‐dimensional coordination polymers under hydrothermal reaction of L with Cd^II or Co^II, in the presence of benzene‐1,4‐dicarboxylic acid (H₂bdc). In poly[[(μ₂‐benzene‐1,4‐dicarboxylato){μ‐1,2‐bis[2‐(1H‐1,3‐imidazol‐1‐ylmethyl)phenoxy]ethane}cadmium(II)] dihydrate], {[Cd(C₈H₄O₄)(C₂₂H₂₂N₄O₂)]·2H₂O}_n, (I), and the cobalt(II) analogue {[Co(C₈H₄O₄)(C₂₂H₂₂N₄O₂)]·2H₂O}_n, (II), the Cd^II and Co^II cations are six‐coordinated by four carboxylate O atoms from two different bdc²⁻ dianions in a chelating mode and two N atoms from two distinct L ligands. The metal ions, bdc²⁻ dianions and L ligands each sit across crystallographic twofold axes. The bdc²⁻ coordination mode and the coordinating orientation of the L ligand play an important role in constructing the novel two‐dimensional framework. Complexes (I) and (II) are threefold interpenetrated two‐dimensional frameworks; their structures are almost isomorphous, while the bond lengths, angles and hydrogen bonds are different in (I) and (II).     

Tetraaquabis(3,5‐dicarboxybenzoato‐O)cobalt(II)

The hydro­thermal reaction of cobalt(II) chloride with trimesate (3,5‐di­carboxy­benzoate) ions in aqueous solution gives the novel title complex, [Co(C₉H₅O₆)₂(H₂O)₄]. The Co^II ion lies on an inversion centre and is octahedrally coordinated to two trimesate anions and four water mol­ecules. Hydro­gen bonds ensure the three‐dimensional architecture of the structure.     

A novel cobalt(II) coordination polymer containing the fumarate anion and o‐phenanthroline

The self‐assembly of three crystallographically distinct fumar­ate ions, two unique cobalt(II) ions and two unique o‐phen­;anthroline mol­ecules results in a two‐dimensional polymeric structure with the formula [Co₂(C₄H₂O₄)₂(C₁₂H₈N₂)₂]_n, namely di‐μ‐fumatato‐bis(o‐phenanthroline)­dicobalt(II). The Co atoms are at the nodes of a two‐dimensional array linked by coordinated fumarate ligands. Each Co atom is coordinated in a distorted octahedral manner to four fumarate O atoms and two N atoms from the chelating phenanthroline ligands.     

Tetra­aqua(2,2′‐bi­pyridine)­nickel(II) terephthalate

The reaction of nickel(II) nitrate with terephthalic acid and 2,2′‐bi­pyridine in di­methyl­form­amide solution gives the title complex, [Ni(C₁₀H₈N₂)(H₂O)₄](C₈H₄O₄). The Ni^II ion is octahedrally coordinated to one 2,2′‐bi­pyridine and four water mol­ecules and does not coordinate to the terephthalate anion. Hydro­gen bonds between the terephthalate anions and the [Ni(2,2′‐bipy)(H₂O)₄]²⁺ cations produce a two‐dimensional hydrogen‐bonding architecture with double sheets.     

Silver(I) sulfate coordination polymers with 4,4′‐bipyridazine and pyridazino[4,5‐d]pyridazine

Poly[[μ₄‐4,4′‐bipyridazine‐μ₅‐sulfato‐disilver(I)] monohydrate], {[Ag₂(SO₄)(C₈H₆N₄)]·H₂O}_n, (I), and poly[[aqua‐μ₄‐pyridazino[4,5‐d]pyridazine‐μ₃‐sulfato‐disilver(I)] monohydrate], {[Ag₂(SO₄)(C₆H₄N₄)(H₂O)]·H₂O}_n, (II), possess three‐ and two‐dimensional polymeric structures, respectively, supported by N‐tetradentate coordination of the organic ligands [Ag—N = 2.208 (3)–2.384 (3) Å] and O‐pentadentate coordination of the sulfate anions [Ag—O = 2.284 (3)–2.700 (2) Å]. Compound (I) is the first structurally examined complex of the new ligand 4,4′‐bipyridazine; it is based upon unprecedented centrosymmetric silver–pyridazine tetramers with tetrahedral AgN₂O₂ and trigonal–bipyramidal AgN₂O₃ coordination of two independent Ag^I ions. Compound (II) adopts a typical dimeric silver–pyridazine motif incorporating two kinds of square‐pyramidal AgN₂O₃ Ag^I ions. The structure exhibits short anion–π interactions involving noncoordinated sulfate O atoms [O...π = 3.041 (3) Å].     

A helical zinc(II) coordination polymer assembled from 1,3‐bis[(pyridin‐3‐yl)methoxy]benzene and benzene‐1,4‐dicarboxylic acid

In catena‐poly[[aqua[1,3‐bis(pyridine‐3‐ylmethoxy)benzene‐κN]zinc(II)]‐μ₂‐benzene‐1,4‐dicarboxylato‐κ²O¹:O⁴], [Zn(C₈H₄O₄)(C₁₈H₁₆N₂O₂)(H₂O)]_n, each Zn^II centre is tetrahedrally coordinated by two O atoms of bridging carboxylate groups from two benzene‐1,4‐dicarboxylate anions (denoted L²⁻), one O atom from a water molecule and one N atom from a 1,3‐bis[(pyridin‐3‐yl)methoxy]benzene ligand (denoted bpmb). (Aqua)O—H...N hydrogen‐bonding interactions induce the formation of one‐dimensional helical [Zn(L)(bpmb)(H₂O)]_n chains which are interlinked through (aqua)O—H...O hydrogen‐bonding interactions, producing two‐dimensional corrugated sheets.     

Influence of nitrogen‐containing chelating ligands on the structures of zinc(II) 4,4′‐ethylenedibenzoates

The Zn^II compounds, μ‐4,4′‐ethylenedibenzoato‐bis[acetatoaqua(dipyrido[3,2‐a:2′,3′‐c]phenazine)zinc(II)] dihydrate, [Zn₂(C₂H₃O₂)₂(C₁₆H₁₀O₄)(C₁₈H₁₀N₄)₂(H₂O)₂]·2H₂O, (I), and catena‐poly[[[aqua(pyrazino[2,3‐f][1,10]phenanthroline)zinc(II)]‐μ‐4,4′‐ethylenedibenzoato] N,N‐dimethylformamide hemisolvate], {[Zn(C₁₆H₁₀O₄)(C₁₄H₈N₄)(H₂O)]·0.5C₃H₇NO}_n, (II), display very different structures because of the influence of the N‐donor chelating ligands. In (I), the coordination geometry of each Zn^II centre is distorted octahedral, involving two N atoms from one dipyrido[3,2‐a:2′,3′‐c]phenazine (L1) ligand, and four O atoms from one bis‐chelating acetate anion, one bridging 4,4′‐ethylenedibenzoate (bpea) ligand and one water molecule. Adjacent Zn^II atoms are bridged by one bpea ligand to form a dinuclear complex, and the dinuclear species is centrosymmetric. Two types of π–π interactions between neighbouring dinuclear species have been found: one is between the L1 ligands, and the second is between the L1 and bpea ligands. In this way, an interesting two‐dimensional supramolecular layer is formed. The layers are further linked by O—H...O and O—H...N hydrogen bonds, generating a three‐dimensional supramolecular network. In (II), each Zn^II atom is square‐pyramidally coordinated by two N atoms from one pyrazino[2,3‐f][1,10]phenanthroline ligand, three O atoms from two different bpea ligands and one water molecule. The two bpea dianions are situated across inversion centres. The bpea dianions bridge neighbouring Zn^II centres, giving a one‐dimensional chain structure in the ab plane. As in (I), two types of π–π interactions between neighbouring chains complete a three‐dimensional supramolecular structure. The results indicate that the structures of the N‐donor chelating ligands are the dominant factors determining the final supramolecular structures of the two compounds.     

Calcium(II) meso‐2,3‐di­phenyl­succinate heptahydrate

The title compound, [Ca(C₁₆H₁₂O₄)(H₂O)₆]·H₂O, adopts a conformation about the central C—C bond that places the two carboxylate groups in an anti orientation. The crystal consists of layers of two‐dimensional arrays of 2,3‐di­phenyl­succinate dianions which are linked by bridging Ca²⁺ cations. The unit cell contains two Ca²⁺ cations in an unusual four‐membered Ca—O—Ca—O ring in which the bridging O atoms belong to water mol­ecules rather than carboxyl­ates, i.e. poly­[[[di‐μ‐aqua‐bis­[penta­aqua­calcium(II)]]‐μ‐(meso‐2,3‐di­phenyl­succinato‐O:O′)] succinate dihydrate].     

Two different anionic manganese(II) coordination polymers constructed through dicyanamide coordination bridges

In order to explore new metal coordination polymers and to search for new types of ferroelectrics among hybrid coordination polymers, two manganese dicyanamide complexes, poly[tetramethylammonium [di‐μ₃‐dicyanamido‐κ⁶N¹:N³:N⁵‐tri‐μ₂‐dicyanamido‐κ⁶N¹:N⁵‐dimanganese(II)]], {[(CH₃)₄N][Mn₂(NCNCN)₅]}_n, (I), and catena‐poly[bis(butyltriphenylphosphonium) [[(dicyanamido‐κN¹)manganese(II)]‐di‐μ₂‐dicyanamido‐κ⁴N¹:N⁵]], {[(C₄H₉)(C₆H₅)₃P]₂[Mn(NCNCN)₄]}_n, (II), were synthesized in aqueous solution. In (I), one Mn^II cation is octahedrally coordinated by six nitrile N atoms from six anionic dicyanamide (dca) ligands, while the second Mn^II cation is coordinated by four nitrile N atoms and two amide N atoms from six anionic dca ligands. Neighbouring Mn^II cations are linked together by μ‐1,5‐ and μ‐1,3,5‐bridging dca anions to form a three‐dimensional polymeric structure. The anionic framework exhibits a solvent‐accessible void of 289.8 ų, amounting to 28.0% of the total unit‐cell volume. Each of the cavities in the network is occupied by only one tetramethylammonium cation. In (II), each Mn^II cation is octahedrally coordinated by six nitrile N atoms from six dca ligands. Neighbouring Mn^II cations are linked together by double dca bridges to form a one‐dimensional polymeric chain, and C—H...N hydrogen‐bonding interactions are involved in the formation of the one‐dimensional layer structure.     

Cationic,neutral and anionic metal(II) complexes derived from 4‐oxo‐4H‐pyran‐2,6‐dicarboxylic acid (chelidonic acid)

The structures of five metal complexes containing the 4‐oxo‐4H‐pyran‐2,6‐dicarboxylate dianion illustrate the remarkable coordinating versatility of this ligand and the great structural diversity of its complexes. In tetraaquaberyllium 4‐oxo‐4H‐pyran‐2,6‐dicarboxylate, [Be(H₂O)₄](C₇H₂O₆), (I), the ions are linked by eight independent O—H...O hydrogen bonds to form a three‐dimensional hydrogen‐bonded framework structure. Each of the ions in hydrazinium(2+) diaqua(4‐oxo‐4H‐pyran‐2,6‐dicarboxylato)calcate, (N₂H₆)[Ca(C₇H₂O₆)₂(H₂O)₂], (II), lies on a twofold rotation axis in the space group P2/c; the anions form hydrogen‐bonded sheets which are linked into a three‐dimensional framework by the cations. In bis(μ‐4‐oxo‐4H‐pyran‐2,6‐dicarboxylato)bis[tetraaquamanganese(II)] tetrahydrate, [Mn₂(C₇H₂O₆)₂(H₂O)₈]·4H₂O, (III), the metal ions and the organic ligands form a cyclic centrosymmetric Mn₂(C₇H₂O₆)₂ unit, and these units are linked into a complex three‐dimensional framework structure containing 12 independent O—H...O hydrogen bonds. There are two independent Cu^II ions in tetraaqua(4‐oxo‐4H‐pyran‐2,6‐dicarboxylato)copper(II), [Cu(C₇H₂O₆)(H₂O)₄], (IV), and both lie on centres of inversion in the space group P; the metal ions and the organic ligands form a one‐dimensional coordination polymer, and the polymer chains are linked into a three‐dimensional framework containing eight independent O—H...O hydrogen bonds. Diaqua(4‐oxo‐4H‐pyran‐2,6‐dicarboxylato)cadmium monohydrate, [Cd(C₇H₂O₆)(H₂O)₂]·H₂O, (V), forms a three‐dimensional coordination polymer in which the organic ligand is coordinated to four different Cd sites, and this polymer is interwoven with a complex three‐dimensional framework built from O—H...O hydrogen bonds.     

Two‐dimensional ZnII and one‐dimensional CoII coordination polymers based on benzene‐1,4‐dicarboxylate and pyridine ligands

Coordination polymers constructed from metal ions and organic ligands have attracted considerable attention owing to their diverse structural topologies and potential applications. Ligands containing carboxylate groups are among the most extensively studied because of their versatile coordination modes. Reactions of benzene‐1,4‐dicarboxylic acid (H₂BDC) and pyridine (py) with Zn^II or Co^II yielded two new coordination polymers, namely, poly[(μ₄‐benzene‐1,4‐dicarboxylato‐κ⁴O:O′:O′′:O′′′)(pyridine‐κN)zinc(II)], [Zn(C₈H₄O₂)(C₅H₅N)]_n, (I), and catena‐poly[aqua(μ₃‐benzene‐1,4‐dicarboxylato‐κ³O:O′:O′′)bis(pyridine‐κN)cobalt(II)], [Co(C₈H₄O₂)(C₅H₅N)₂(H₂O)]_n, (II). In compound (I), the Zn^II cation is five‐coordinated by four carboxylate O atoms from four BDC²⁻ ligands and one pyridine N atom in a distorted square‐pyramidal coordination geometry. Four carboxylate groups bridge two Zn^II ions to form centrosymmetric paddle‐wheel‐like Zn₂(μ₂‐COO)₄ units, which are linked by the benzene rings of the BDC²⁻ ligands to generate a two‐dimensional layered structure. The two‐dimensional layer is extended into a three‐dimensional supramolecular structure with the help of π–π stacking interactions between the aromatic rings. Compound (II) has a one‐dimensional double‐chain structure based on Co₂(μ₂‐COO)₂ units. The Co^II cations are bridged by BDC²⁻ ligands and are octahedrally coordinated by three carboxylate O atoms from three BDC²⁻ ligands, one water O atom and two pyridine N atoms. Interchain O—H…O hydrogen‐bonding interactions link these chains to form a three‐dimensional supramolecular architecture.     

Bis(5‐aminotetrazole‐1‐acetato‐κO)tetraaquacobalt(II) and catena‐poly[[cadmium(II)]‐bis(μ‐5‐aminotetrazole‐1‐acetato‐κ3N4:O,O′)]

The Co^II atom in bis(5‐aminotetrazole‐1‐acetato)tetraaquacobalt(II), [Co(C₃H₄N₅O₂)₂(H₂O)₄], (I), is octahedrally coordinated by six O atoms from two 5‐aminotetrazole‐1‐acetate (atza) ligands and four water molecules. The molecule has a crystallographic centre of symmetry located at the Co^II atom. The molecules of (I) are interlinked by hydrogen‐bond interactions, forming a two‐dimensional supramolecular network structure in the ac plane. The Cd^II atom in catena‐poly[[cadmium(II)]‐bis(μ‐5‐aminotetrazole‐1‐acetato], [Cd(C₃H₄N₅O₂)₂]_n, (II), lies on a twofold axis and is coordinated by two N atoms and four O atoms from four atza ligands to form a distorted octahedral coordination environment. The Cd^II centres are connected through tridentate atza bridging ligands to form a two‐dimensional layered structure extending along the ab plane, which is further linked into a three‐dimensional structure through hydrogen‐bond interactions.     

mer‐Diaquabis(1H‐imidazole‐κN3)[orotato(2–)]cobalt(II)

In the title complex, mer‐diaqua[2,6‐dioxo‐1,2,3,6‐tetrahydropyrimidine‐4‐carboxylato(2−)]bis(1H‐imidazole‐κN³)cobalt(II), [Co(C₅H₂N₂O₄)(C₃H₄N₂)₂(H₂O)₂], the Co^II ion is coordinated by a deprotonated N atom and the carboxylate O atom of the orotate ligand, two imidazole N atoms and two aqua ligands in a distorted octahedral geometry. The title complex exists as discrete doubly hydrogen‐bonded dimers, and a three‐dimensional network of O—H...O and N—H...O hydrogen bonds and weak π–π interactions is responsible for crystal stabilization.     

CdII and CoII coordination polymers constructed from benzene‐1,4‐dicarboxylic acid and 2‐(pyridin‐3‐yl)‐1H‐benzimidazole ligands

In poly[aqua(μ₃‐benzene‐1,4‐dicarboxylato‐κ⁵O¹,O^1′:O¹:O⁴,O^4′)[2‐(pyridin‐3‐yl‐κN)‐1H‐benzimidazole]cadmium(II)], [Cd(C₈H₄O₄)(C₁₂H₉N₃)(H₂O)]_n, (I), each Cd^II ion is seven‐coordinated by the pyridine N atom from a 2‐(pyridin‐3‐yl)benzimidazole (3‐PyBIm) ligand, five O atoms from three benzene‐1,4‐dicarboxylate (1,4‐bdc) ligands and one O atom from a coordinated water molecule. The complex forms an extended two‐dimensional carboxylate layer structure, which is further extended into a three‐dimensional network by hydrogen‐bonding interactions. In catena‐poly[[diaquabis[2‐(pyridin‐3‐yl‐κN)‐1H‐benzimidazole]cobalt(II)]‐μ₂‐benzene‐1,4‐dicarboxylato‐κ²O¹:O⁴], [Co(C₈H₄O₄)(C₁₂H₉N₃)₂(H₂O)₂]_n, (II), each Co^II ion is six‐coordinated by two pyridine N atoms from two 3‐PyBIm ligands, two O atoms from two 1,4‐bdc ligands and two O atoms from two coordinated water molecules. The complex forms a one‐dimensional chain‐like coordination polymer and is further assembled by hydrogen‐bonding interactions to form a three‐dimensional network.     

Co(C2(COO)2)(H2O)4 · 2 H2O und Co(C2(COO)2)(H2O)2: zwei Koordinationspolymere mit dem Acetylendicarboxylat‐Dianion

Co(C₂(COO)₂)(H₂O)₄ · 2 H₂O and Co(C₂(COO)₂)(H₂O)₂: Two Co‐ordination Polymers of the Acetylenedicarboxylate Dianion By reaction of CoCO₃ with an aqueous solution of acetylenedicarboxylic acid and subsequent crystallisation single‐crystals of Co(C₂(COO)₂)(H₂O)₄ · 2 H₂O were obtained (P2₁/a, Z = 2). In the solid state structure cobalt is octahedrally surrounded by four water molecules and two oxygen atoms of the carboxylate anions. These octahedra are connected to chains by the dicarboxylates. Already at ambient conditions Co(C₂(COO)₂)(H₂O)₄ · 2 H₂O looses four water molecules to give Co(C₂(COO)₂)(H₂O)₂ (isotypic to Mn[C₂(COO)₂] · 2 H₂O, C2/c, Z = 4). The cobalt cation is now octahedrally co‐ordinated by two water molecules and four oxygen atoms of the dicarboxylate ligands, which connect the Co octahedra to a three dimensional network. Thermoanalytical investigations show another mass loss at about 200 °C, which leads to non‐crystalline products. Measurements of the magnetic susceptibilities result in the expected behaviour for Co²⁺ in an octahedral co‐ordination (high spin, ⁴T₁ ground state). The effective magnetic moment at room temperature is n_eff = 5.51 μ_B.     

In situ single‐crystal to single‐crystal (SCSC) transformation of the one‐dimensional polymer catena‐poly[[diaqua(sulfato)copper(II)]‐μ2‐glycine] into the two‐dimensional polymer poly[μ2‐glycine‐μ4‐sulfato‐copper(II)]

The one‐dimensional coordination polymer catena‐poly[diaqua(sulfato‐κO)copper(II)]‐μ₂‐glycine‐κ²O:O′], [Cu(SO₄)(C₂H₅NO₂)(H₂O)₂]_n, (I), was synthesized by slow evaporation under vacuum of a saturated aqueous equimolar mixture of copper(II) sulfate and glycine. On heating the same blue crystal of this complex to 435 K in an oven, its aspect changed to a very pale blue and crystal structure analysis indicated that it had transformed into the two‐dimensional coordination polymer poly[(μ₂‐glycine‐κ²O:O′)(μ₄‐sulfato‐κ⁴O:O′:O′′:O′′)copper(II)], [Cu(SO₄)(C₂H₅NO₂)]_n, (II). In (I), the Cu^II cation has a pentacoordinate square‐pyramidal coordination environment. It is coordinated by two water molecules and two O atoms of bridging glycine carboxylate groups in the basal plane, and by a sulfate O atom in the apical position. In complex (II), the Cu^II cation has an octahedral coordination environment. It is coordinated by four sulfate O atoms, one of which bridges two Cu^II cations, and two O atoms of bridging glycine carboxylate groups. In the crystal structure of (I), the one‐dimensional polymers, extending along [001], are linked via N—H...O, O—H...O and bifurcated N—H...O,O hydrogen bonds, forming a three‐dimensional framework. In the crystal structure of (II), the two‐dimensional networks are linked via bifurcated N—H...O,O hydrogen bonds involving the sulfate O atoms, forming a three‐dimensional framework. In the crystal structures of both compounds, there are C—H...O hydrogen bonds present, which reinforce the three‐dimensional frameworks.     

Two two‐dimensional MnII and NaI coordination polymers constructed by the flexible benzene‐1,4‐dioxy­acetate ligand

Two new two‐dimensional coordination polymers, poly­[[[aqua(2,2′‐bi­pyridine‐κ²N,N′)manganese(II)]‐μ₃‐p‐phenyl­enebis­(oxy­acet­ato)‐κ³O:O′:O′′] dihydrate], {[Mn(C₁₀H₈O₆)(C₁₀H₈N₂)(H₂O)]·2H₂O}_n, (I), and poly­[[di‐μ‐aqua‐bis­[aqua­sodium(I)]]‐μ₄‐p‐phenyl­enebis­(oxy­acetato)‐κO:O′,O′′:O′′′,O′′′′:O′′′′′], [Na₂(C₁₀H₈O₆)(H₂O)₄]_n, (II), have been synthesized and characterized by X‐ray single‐crystal diffraction. In (I), there are two 1,4‐BDOA²⁻ [p‐phenyl­enebis­(oxy­acetate) or, more commonly, benzene‐1,4‐dioxy­acetate] ligands, each lying about inversion centres, while in (II), there is one such ligand and it also has crystallographically imposed inversion symmetry. In (I), each Mn^II atom displays an octahedral MnN₂O₄ configuration, defined by three carboxyl O atoms of different 1,4‐BDOA²⁻ groups, two N atoms of one 2,2′‐bi­pyridine ligand and one water mol­ecule. In (II), each Na^I atom is octahedrally coordinated by one ether O atom, two carboxyl O atoms of different 1,4‐BDOA²⁻ ligands and three water mol­ecules. The metal ions in complexes (I) and (II) are bridged by 1,4‐BDOA²⁻ groups into two‐dimensional layer structures. Furthermore, three‐dimensional supramolecular networks are constructed via hydrogen bonds in (I) and (II), and by additional π–π stacking interactions in (I).     

Poly[[trans‐diaquabis(μ2‐biphenyl‐2,2′‐dicarboxylato)bis(μ2‐4,4′‐bipyridine)dicobalt(II)] biphenyl‐2,2′‐dicarboxylic acid disolvate]

In the title compound, {[Co₂(C₁₄H₈O₄)₂(C₁₀H₈N₂)₂(H₂O)₂]·2C₁₄H₁₀O₄}_n, each Co^II ion is six‐coordinate in a slightly distorted octahedral geometry. Both Co^II ions are located on twofold axes. One is surrounded by two O atoms from two biphenyl‐2,2′‐dicarboxylate (dpa) dianions, two N atoms from two 4,4′‐bipyridine (bpy) ligands and two water molecules, while the second is surrounded by four O atoms from two dpa dianions and two N atoms from two bpy ligands. The coordinated dpa dianion functions as a κ³‐bridge between the two Co^II ions. One carboxylate group of a dpa dianion bridges two adjacent Co^II ions, and one O atom of the other carboxylate group also chelates to a Co^II ion. The Co^II ions are bridged by dpa dianions and bpy ligands to form a chiral sheet. There are several strong intermolecular hydrogen bonds between the H₂dpa solvent molecule and the chiral sheet, which result in a sandwich structure.