A twofold interpenetrating three‐dimensional CdII coordination framework: poly[[μ2‐1,3‐bis(2‐methyl‐1H‐imidazol‐1‐yl)benzene](μ3‐5‐nitrobenzene‐1,3‐dicarboxylato)cadmium(II)]

A twofold interpenetrating three‐dimensional Cd^II coordination framework, [Cd(C₈H₃NO₆)(C₁₄H₁₄N₄)]_n, has been prepared and characterized by IR spectroscopy, elemental analysis, thermal analysis and single‐crystal X‐ray diffraction. The asymmetric unit consists of a divalent Cd^II atom, one 1,3‐bis(2‐methyl‐1H‐imidazol‐1‐yl)benzene (1,3‐BMIB) ligand and one fully deprotonated 5‐nitrobenzene‐1,3‐dicarboxylate (NO₂‐BDC²⁻) ligand. The coordination sphere of the Cd^II atom consists of five O‐donor atoms from three different NO₂‐BDC²⁻ ligands and two imidazole N‐donor atoms from two different 1,3‐BMIB ligands, forming a distorted {CdN₂O₅} pentagonal bipyramid. The NO₂‐BDC ligand links three Cd^II atoms via a μ₁‐η¹:η¹ chelating mode and a μ₂‐η²:η¹ bridging mode. The title compound is a twofold interpenetrating 3,5‐connected network with the {4².6⁵.8³}{4².6} topology. In addition, the compound exhibits fluorescence emissions in the solid state at room temperature.     

Poly[(μ4‐biphenyl‐3,3′,4,4′‐tetracarboxylato)bis[μ2‐1,4‐bis(imidazol‐1‐ylmethyl)benzene]dicobalt(II)]

The asymmetric unit of the title two‐dimensional coordination polymer, [Co₂(C₁₆H₆O₈)(C₁₄H₁₄N₄)₂]_n, contains one Co²⁺ ion, half of a biphenyl‐3,3′,4,4′‐tetracarboxylate (bptc) anion lying about an inversion centre and one 1,4‐bis(imidazol‐1‐ylmethyl)benzene (bix) ligand. The Co^II atom is coordinated by three carboxylate O atoms from two different bptc ligands and two N atoms from two bix ligands constructing a distorted square pyramid. Each Co²⁺ ion is interlinked by two bptc anions, while each bptc anion coordinates to four Co atoms as a hexadentate ligand so that four Co^II atoms and four bptc anions afford a larger 38‐membered ring. These inorganic rings are further extended into a two‐dimensional undulated network in the (10) plane. Two Co^II atoms in adjacent 38‐membered rings are joined together by pairs of bix ligands forming a 26‐membered [Co₂(bix)₂] ring that is penetrated by a bptc anion; these components share a common inversion centre.     

Poly[[(μ2‐biphenyl‐2,4′‐dicarboxylato)[μ2‐1,4‐bis(imidazol‐1‐ylmethyl)benzene]cadmium(II)] 0.15‐hydrate]

The asymmetric unit of the title two‐dimensional coordination polymer, {[Cd(C₁₄H₈O₄)(C₁₄H₁₄N₄)]·0.15H₂O}_n, is composed of one Cd^II cation, one biphenyl‐2,4′‐dicarboxylate (bpdc) anion, one 1,4‐bis(imidazol‐1‐ylmethyl)benzene (bix) ligand and 0.15 solvent water molecules. The coordination environment of the Cd^II cation is defined by four carboxylate O atoms from two different bpdc anions in a chelating mode and two N atoms from two distinct bix ligands, constructing a distorted trigonal prism polyhedron. Two inversion‐related Cd^II cations are bridged together by two positionally disordered bpdc anions, forming a 22‐membered ring with a Cd...Cd distance of 9.1966 (9) Å. These rings are then further linked by two bix ligands, extending into a two‐dimensional layer along (102) with 6³ topology.     

Poly[[sesqui[μ2‐1,4‐bis(imidazol‐1‐ylmethyl)benzene‐κ2N:N′](carbonato‐κ2O,O′)copper(II)] 1,4‐bis(imidazol‐1‐ylmethyl)benzene hemisolvate pentahydrate]

The asymmetric unit of the title compound, {[Cu(CO₃)(C₁₄H₁₄N₄)_1.5]·0.5C₁₄H₁₄N₄·5H₂O}_n, contains one Cu^II cation in a slightly distorted square‐pyramidal coordination environment, one CO₃²⁻ anion, one full and two half 1,4‐bis(imidazol‐1‐ylmethyl)benzene (bix) ligands, one half‐molecule of which is uncoordinated, and five uncoordinated water molecules. One of the coordinated bix ligands and the uncoordinated bix molecule are situated about centers of symmetry, located at the centers of the benzene rings. The coordinated bix ligands link the copper(II) ions into a [Cu(bix)_1.5]_n molecular ladder. These molecular ladders do not form interpenetrated ladders but are arranged in an ABAB parallel terrace, i.e. with the ladders arranged one above another, with sequence A translated with respect to B by 8 Å. To best of our knowledge, this arrangement has not been observed in any of the molecular ladder frameworks synthesized to date. The coordination environment of the Cu^II atom is completed by two O atoms of the CO₃²⁻ anion. The framework is further strengthened by extensive O—H...O and O—H...N hydrogen bonds involving the water molecules, the O atoms of the CO₃²⁻ anion and the N atoms of the bix ligands. This study describes the first example of a molecular ladder coordination polymer based on bix and therefore demonstrates further the usefulness of bix as a versatile multidentate ligand for constructing coordination polymers with interesting architectures.     

A three‐dimensional coordination polymer based on the Zn4(μ3‐OH)2 unit: poly[[(μ4‐benzene‐1,4‐dicarboxylato)bis(μ3‐benzene‐1,4‐dicarboxylato)bis(μ3‐hydroxido)bis(1,10‐phenanthroline‐5,6‐dione)tetrazinc] dihydrate]

The title compound, {[Zn₄(C₈H₄O₄)₃(OH)₂(C₁₂H₆N₂O₂)₂]·2H₂O}_n, has been prepared hydrothermally by the reaction of Zn(NO₃)₂·6H₂O with benzene‐1,4‐dicarboxylic acid (H₂bdc) and 1,10‐phenanthroline‐5,6‐dione (pdon) in H₂O. In the crystal structure, a tetranuclear Zn₄(OH)₂ fragment is located on a crystallographic inversion centre which relates two subunits, each containing a [ZnN₂O₄] octahedron and a [ZnO₄] tetrahedron bridged by a μ₃‐OH group. The pdon ligand chelates to zinc through its two N atoms to form part of the [ZnN₂O₄] octahedron. The two crystallographically independent bdc²⁻ ligands are fully deprotonated and adopt μ₃‐κO:κO′:κO′′ and μ₄‐κO:κO′:κO′′:κO′′′ coordination modes, bridging three or four Zn^II cations, respectively, from two Zn₄(OH)₂ units. The Zn₄(OH)₂ fragment connects six neighbouring tetranuclear units through four μ₃‐bdc²⁻ and two μ₄‐bdc²⁻ ligands, forming a three‐dimensional framework with uninodal 6‐connected α‐Po topology, in which the tetranuclear Zn₄(OH)₂ units are considered as 6‐connected nodes and the bdc²⁻ ligands act as linkers. The uncoordinated water molecules are located on opposite sides of the Zn₄(OH)₂ unit and are connected to it through hydrogen‐bonding interactions involving hydroxide and carboxylate groups. The structure is further stabilized by extensive π–π interactions between the pdon and μ₄‐bdc²⁻ ligands.     

The two‐dimensional coordination polymer poly[[bis(3‐methyl­pyridine)­cadmium(II)]‐tetra‐μ‐cyano‐nickel(II)]

The title complex, [CdNi(CN)₄(C₆H₇N)₂]_n, adopts a slightly distorted octahedral geometry around the Cd centre. Four cyanide N atoms occupy the equatorial coordination sites around the Cd centre. The structure consists of corrugated and cyanide‐bridged polymeric networks made up of tetracyano­nickelate ions coordinated to cadmium, with the Ni ion coordinated by four cyanide ligands in a square‐planar arrangement. The Cd and Ni atoms occupy special positions of 2/m site symmetry. The 3‐methyl­pyridine group, except for two methyl H atoms, lies on a crystallographic mirror plane. The 3‐methyl­pyridine molecules, bound to cadmium in trans positions, are located on both sides of the network. The bonding in the networks occurs because of a departure of the Ni—C—N—Cd sequence of atoms from linearity at the C and N atoms.     

Poly[[μ2‐1,3‐bis(pyridin‐4‐yl)propane](μ3‐1,4‐phenylenediacetato)cadmium]

Solvothermal reaction between Cd(NO₃)₂, 1,4‐phenylenediacetate (1,4‐PDA) and 1,3‐bis(pyridin‐4‐yl)propane (bpp) afforded the title complex, [Cd(C₁₀H₈O₄)(C₁₃H₁₄N₂)]_n. Adjacent carboxylate‐bridged Cd^II ions are related by an inversion centre. The 1,4‐PDA ligands adopt a cis conformation and connect the Cd^II ions to form a one‐dimensional chain extending along the c axis. These chains are in turn linked into a two‐dimensional network through bpp bridges. The bpp ligands adopt an anti–gauche conformation. From a topological point of view, each bpp ligand and each pair of 1,4‐PDA ligands can be considered as linkers, while the dinuclear Cd^II unit can be regarded as a 6‐connecting node. Thus, the structure can be simplified to a two‐dimensional 6‐connected network.     

A two‐dimensional coordination polymer containing a two‐dimensional zinc–carboxylate layer constructed from helical chains: poly[(μ4‐benzene‐1,2‐dicarboxylato)zinc(II)]

The title compound, [Zn(C₈H₄O₄)]_n, consists of one Zn^II cation and one benzene‐1,2‐dicarboxylate dianion (BDC²⁻) as the building unit. The Zn^II cation is four‐coordinated by four carboxylate O atoms from four dianionic BDC²⁻ ligands in a distorted tetrahedral geometry. The Zn^II cations are linked by the BDC²⁻ ligands to generate a structure featuring two‐dimensional zinc–carboxylate layers containing left‐ and right‐handed helical chains. The two‐dimensional layers are stacked along the a direction. The thermal stability of the title compound has been studied.     

A two‐dimensional coordination polymer: poly[diaqua(μ4‐4,4′‐oxydibenzoato)(μ2‐4,4′‐oxydibenzoato)dilead(II)]

In a new two‐dimensional coordination polymer, [Pb(C₁₄H₈O₅)(H₂O)]_n, the asymmetric unit consists of a Pb^II cation, two halves of two crystallographically distinct fully deprotonated 4,4′‐oxydibenzoate ligands and one aqua ligand. Single‐crystal X‐ray diffraction analysis reveals that the compound is a coordination polymer with the point symbol {5³}₂{5⁴.8²}. In addition, it exhibits a strong fluorescence emission in the solid state at room temperature.     

A novel two‐dimensional (4,4) network based on dinuclear cadmium secondary building units: poly[(μ5‐benzene‐1,4‐diacetato)[μ2‐1,4‐bis(1,2,4‐triazol‐1‐yl)butane]cadmium(II)]

In the title mixed‐ligand metal–organic polymeric compound, [Cd(C₁₀H₈O₄)(C₈H₁₂N₆)]_n or [Cd(PBEA)(BTB)]_n [H₂PBEA is benzene‐1,4‐diacetic acid and BTB is 1,4‐bis(1,2,4‐triazol‐1‐yl)butane], the asymmetric unit contains one Cd^II ion, one BTB molecule and one PBEA²⁻ anion. The Cd^II ion is in a slightly distorted pentagonal–bipyramidal geometry, coordinated by five carboxylate O atoms from three distinct PBEA²⁻ anions and by two BTB N atoms. There are two coordination patterns for the carboxylate groups of the PBEA²⁻ ligand, one being a μ₁‐η¹:η¹ chelating mode and the other a μ₂‐η²:η¹ bridging mode, while the BTB molecule shows a trans–trans–trans conformation. The crystal structure is constructed from the secondary building unit (SBU) [Cd₂(CO₂)₄N₂O₂], in which the two metal centres are held together by two PBEA²⁻ linkers. The SBU is connected by BTB and PBEA²⁻ bridges to form a two‐dimensional grid‐like (4,4) layer with meshes of dimensions 14.69 × 11.28 Å.     

A novel two‐dimensional nickel(II) coordination polymer with 1,4‐bis(1,2,4‐triazol‐1‐ylmethyl)benzene and azide ligands

The coordination geometry of the Ni^II atom in the title complex, poly[diazidobis[μ‐1,4‐bis(1,2,4‐triazol‐1‐ylmethyl)benzene‐κ²N⁴:N^4′]nickel(II)], [Ni(N₃)₂(C₁₂H₁₂N₆)₂]_n, is a distorted octahedron, in which the Ni^II atom lies on an inversion centre and is coordinated by four N atoms from the triazole rings of two symmetry‐related pairs of 1,4‐bis(1,2,4‐triazol‐1‐ylmethyl)benzene (bbtz) ligands and two N atoms from two symmetry‐related monodentate azide ligands. The Ni^II atoms are bridged by four bbtz ligands to form a two‐dimensional (4,4)‐network.     

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.     

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.     

A twofold interwoven two‐dimensional→two‐dimensional (2‐D→2‐D) cluster–organic network based on the [Cu2I2] cluster and the 4,4′‐(diazenediyl)dipyridine ligand: poly[[μ2‐4,4′‐(diazenediyl)dipyridine]‐μ2‐iodido‐copper(I)]

In the polymeric title compound, [CuI(C₁₀H₈N₄)]_n, the Cu^I atom is in a four‐coordinated tetrahedral geometry, formed by two I atoms and two pyridine N atoms from two different 4,4′‐(diazenediyl)dipyridine (4,4′‐azpy) ligands. Two μ₂‐I atoms link two Cu^I atoms to form a planar rhomboid [Cu₂I₂] cluster located on an inversion centre, where the distance between two Cu^I atoms is 2.7781 (15) Å and the Cu—I bond lengths are 2.6290 (13) and 2.7495 (15) Å. The bridging 4,4′‐azpy ligands connect the [Cu₂I₂] clusters into a two‐dimensional (2‐D) double‐layered grid‐like network [parallel to the (10) plane], with a (4,4)‐connected topology. Two 2‐D grid‐like networks interweave each other by long 4,4′‐azpy bridging ligands to form a dense 2‐D double‐layered network. To the best of our knowledge, this interwoven 2‐D→2‐D network is observed for the first time in [Cu₂I₂]–organic compounds.     

A novel two‐dimensional cadmium(II) complex: poly[diaquatris(μ4‐cyclohexane‐1,4‐dicarboxylato)bis[2‐(pyridin‐4‐yl)‐1H‐benzimidazole]tricadmium(II)

The title compound, [Cd₃(C₈H₁₀O₄)₃(C₁₂H₉N₃)₂(H₂O)₂]_n or [Cd₃(chdc)₃(4‐PyBIm)₂(H₂O)₂]_n, was synthesized hydrothermally from the reaction of Cd(CH₃COO)₂·2H₂O with 2‐(pyridin‐4‐yl)‐1H‐benzimidazole (4‐PyBIm) and cyclohexane‐1,4‐dicarboxylic acid (1,4‐chdcH₂). The asymmetric unit consists of one and a half Cd^II cations, one 4‐PyBIm ligand, one and a half 1,4‐chdc²⁻ ligands and one coordinated water molecule. The central Cd^II cation, located on an inversion centre, is coordinated by six carboxylate O atoms from six 1,4‐chdc²⁻ ligands to complete an elongated octahedral coordination geometry. The two terminal rotationally symmetric Cd^II cations each exhibits a distorted pentagonal–bipyramidal geometry, coordinated by one N atom from 4‐PyBIm, five O atoms from three 1,4‐chdc²⁻ ligands and one O atom from an aqua ligand. The 1,4‐chdc²⁻ ligands possess two conformations, i.e.e,e‐trans‐chdc²⁻ and e,a‐cis‐chdc²⁻. The cis‐1,4‐chdc²⁻ ligands bridge the Cd^II cations to form a trinuclear {Cd₃}‐based chain along the b axis, while the trans‐1,4‐chdc²⁻ ligands further link adjacent one‐dimensional chains to construct an interesting two‐dimensional network.     

Poly[[diaqua‐μ‐4,4′‐bipyridine‐dinitratodi‐μ‐l‐tyrosinato‐dicopper(II)]: a chiral two‐dimensional coordination polymer

The title compound, [Cu₂(C₉H₁₀NO₃)₂(NO₃)₂(C₁₀H₈N₂)(H₂O)₂]_n, contains Cu^II atoms and l ‐tyrosinate (l ‐tyr) and 4,4′‐bipyridine (4,4′‐bipy) ligands in a 2:2:1 ratio. Each Cu atom is coordinated by one amino N atom and two carboxylate O atoms from two l ‐tyr ligands, one N atom from a 4,4′‐bipy ligand, a monodentate nitrate ion and a water molecule in an elongated octahedral geometry. Adjacent Cu atoms are bridged by the bidentate carboxylate groups into a chain. These chains are further linked by the bridging 4,4′‐bipy ligands, forming an undulated chiral two‐dimensional sheet. O—H...O and N—H...O hydrogen bonds connect the sheets in the [100] direction. This study offers useful information for the engineering of chiral coordination polymers with amino acids and 4,4′‐bipy ligands by considering the ratios of the metal ion and organic components.     

The first three‐dimensional FeIII–SrII heterometallic coordination polymer: poly[[diaquatetrakis(μ3‐pyridine‐2,3‐dicarboxylato)diiron(III)strontium(II)] dihydrate]

The title compound, poly[[diaqua‐1κ²O‐tetrakis(μ₃‐pyridine‐2,3‐dicarboxylato)‐2:1:2′κ¹⁰N,O²:O^2′,O³:O^3′;2:1:2′κ⁸O³:O^3′:N,O²‐diiron(III)strontium(II)] dihydrate], {[Fe₂Sr(C₇H₃O₄)₄(H₂O)₂]·2H₂O}_n, which has triclinic (P) symmetry, was prepared by the reaction of pyridine‐2,3‐dicarboxylic acid, SrCl₂·6H₂O and Fe(OAc)₂(OH) (OAc is acetate) in the presence of imidazole in water at 363 K. In the crystal structure, the pyridine‐2,3‐dicarboxylate (pydc²⁻) ligand exhibits μ₃‐η¹,η¹:η¹:η¹ and μ₃‐η¹,η¹:η¹,η¹:η¹ coordination modes, bridging two Fe^III cations and one Sr^II cation. The Sr^II cation, which is located on an inversion centre, is eight‐coordinated by six O atoms of four pydc²⁻ ligands and two water molecules. The coordination geometry of the Sr^II cation can be best described as distorted dodecahedral. The Fe^III cation is six‐coordinated by O and N atoms of four pydc²⁻ ligands in a slightly distorted octahedral geometry. Each Fe^III cation bridges two neighbouring Fe^III cations to form a one‐dimensional [Fe₂(pydc)₄]_n chain. The chains are connected by Sr^II cations to form a three‐dimensional framework. The topology type of this framework is tfj . The structure displays O—H...O and C—H...O hydrogen bonding.     

Poly[deca‐μ2‐cyanido‐dicyanidobis(μ2‐ethylenediamine)bis(ethylenediamine)tricadmium(II)dicobalt(III)]: a two‐dimensional coordination polymer

The title coordination polymer, [Cd₃Co₂(CN)₁₂(C₂H₈N₂)₄]_n, has an infinite two‐dimensional network structure. The asymmetric unit is composed of two crystallographically independent Cd^II atoms, one of which is located on a twofold rotation axis. There are two independent ethylenediamine (en) ligands, one of which bis‐chelates to the Cd atom that sits in a general position, while the other bridges this Cd atom to that sitting on the twofold axis. The Cd atom located on the twofold rotation axis is linked to four equivalent Co^III atoms via cyanide bridges, while the Cd atom that sits in a general position is connected to three equivalent Co^III atoms via cyanide bridges. In this way, a series of trinuclear, tetranuclear and pentanuclear macrocycles are linked to form a two‐dimensional network structure lying parallel to the bc plane. In the crystal structure, these two‐dimensional networks are linked via N—H...N hydrogen bonds involving an en NH₂ H atom and a cyanide N atom, leading to the formation of a three‐dimensional structure. This coordination polymer is only the second example involving a cyanometallate where the en ligand is present in both chelating and bridging coordination modes.     

A novel three‐dimensional CdII coordination polymer: poly[[aquabis(2,2′‐bipyridine)(μ5‐pyrazol‐1‐ide‐3,5‐dicarboxylato)(μ4‐pyrazol‐1‐ide‐3,5‐dicarboxylato)(μ3‐pyrazole‐3,5‐dicarboxylato)tetracadmium(II)] dihydrate]

The title compound, {[Cd₄(C₅H₂N₂O₄)(C₅HN₂O₄)₂(C₁₀H₈N₂)₂(H₂O)]·2H₂O}_n, crystallized in the monoclinic space group P2₁/n and displays a three‐dimensional architecture. The asymmetric unit is composed of four crystallographically independent Cd^II centres, two triply deprotonated pyrazole‐3,5‐dicarboxylic acid molecules, one doubly deprotonated pyrazole‐3,5‐dicarboxylic acid molecule, two 2,2′‐bipyridine ligands, one coordinated water molecule and two interstitial water molecules. Interestingly, the Cd^II centers exhibit two different coordination numbers. Two Cd^II centres adopt a distorted octahedral arrangement and a third a trigonal–prismatic geometry, though they are all hexacoordinated. However, the fourth Cd^II center is heptacoordinated and displays a pentagonal–bipyramidal geometry. The three anionic ligands adopt μ₃‐, μ₄‐ and μ₅‐bridging modes, first linking Cd^II centers into a one‐dimensional wave‐like band, then into a wave‐like layer and finally into a three‐dimensional coordination framework, which is stabilized by hydrogen bonds.     

Poly[bis(μ4‐benzene‐1,2‐dicarboxylato)di‐μ3‐isonicotinato‐dilanthanum(III)]

In the title compound, [La₂(C₈H₄O₄)₂(C₆H₄NO₂)₂]_n, there are two crystallographically independent La centres, both nine‐coordinated in tricapped trigonal prismatic coordination geometries by eight carboxylate O atoms and one pyridyl N atom. The La centres are linked by the carboxylate groups of isonicotinate (IN⁻) and benzene‐1,2‐dicarboxylate (BDC²⁻) ligands to form La–carboxylate chains, which are further expanded into a three‐dimensional framework with nanometre‐sized channels by La—N bonds. In the construction of the resultant architecture, in tricapped trigonal prismatic coordination geometries by eight carboxylate O atoms and one pyridyl N atom, while the BDC ligands link to four different cations each, displaying penta‐ and heptadentate chelating–bridging modes, respectively.