Poly[aqua[μ2‐1,4‐bis(imidazol‐1‐ylmethyl)benzene‐κ2N3:N3′](μ2‐5‐hydroxybenzene‐1,3‐dicarboxylato‐κ4O1,O1′:O3,O3′)cadmium(II)], a twofold interpenetrated CdSO4‐like metal–organic polymer

In the title cadmium(II) complex, [Cd(C₈H₄O₅)(C₁₄H₁₄N₄)(H₂O)]_n, the 5‐hydroxybenzene‐1,3‐dicarboxylate (5‐OH‐1,3‐bdc) and 1,4‐bis(imidazol‐1‐ylmethyl)benzene (1,4,‐bix) ligands bridge water‐coordinated Cd^II atoms to generate a three‐dimensional network. Two carboxylate groups from different ligands function as O,O′‐chelates, while two imidazole N atoms from different ligands coordinate in a monodentate fashion, and one water molecule completes the seven‐coordinate pentagonal bipyramid around the Cd^II atom, in which the N atoms occupy the axial sites and the O atoms occupy the equatorial sites. The overall architecture is a twofold interpenetrated CdSO₄‐type framework. The two crystallographically equivalent frameworks are linked by O—H...O hydrogen bonds between the water, hydroxy and carboxylate groups.     

Poly[aqua(μ2‐benzene‐1,4‐dicarboxylato)(μ2‐4,4′‐bipyridine N,N′‐dioxide)cadmium(II)], a threefold interpenetrating diamond net

In the title compound, [Cd(C₈H₄O₄)(C₁₀H₈N₂O₂)(H₂O)]_n, (I), each Cd^II atom is seven‐coordinated in a distorted monocapped trigonal prismatic coordination geometry, surrounded by four carboxylate O atoms from two different benzene‐1,4‐dicarboxylate (1,4‐bdc) anions, two O atoms from two distinct 4,4′‐bipyridine N,N′‐dioxide (bpdo) ligands and one water O atom. The Cd^II atom and the water O atom are on a twofold rotation axis. The bpdo and 1,4‐bdc ligands are on centers of inversion. Each crystallographically unique Cd^II center is bridged by the 1,4‐bdc dianions and bpdo ligands to give a three‐dimensional diamond framework containing large adamantanoid cages. Three identical such nets are interlocked with each other, thus directly leading to the formation of a threefold interpenetrated three‐dimensional diamond architecture. To the best of our knowledge, (I) is the first example of a threefold interpenetrating diamond net based on both bpdo and carboxylate ligands. There are strong linear O—H...O hydrogen bonds between the water molecules and carboxylate O atoms within different diamond nets. Each diamond net is hydrogen bonded to its two neighbors through these hydrogen bonds, which further consolidates the threefold interpenetrating diamond framework.     

Poly[di‐μ‐aqua‐μ‐1,2‐bis(pyridin‐4‐yl)ethene‐κ2N:N′‐tetrakis(4‐iodobenzoato‐κ2O,O′)dicadmium]

Colourless crystals of the title compound, [Cd₂(C₇H₄IO₂)₄(C₁₂H₁₀N₂)(H₂O)₂]_n, were obtained by the self‐assembly of Cd(NO₃)₂·4H₂O, 1,2‐bis(pyridin‐4‐yl)ethene (bpe) and 4‐iodobenzoic acid (4‐IBA). Each Cd^II atom is seven‐coordinated in a pentagonal–bipyramidal coordination environment by four carboxylate O atoms from two different 4‐IBA ligands, two O atoms from two water molecules and one N atom from a bpe ligand. The Cd^II centres are bridged by the aqua molecules and bpe ligands, which lie across centres of inversion, to give a two‐dimensional net. Topologically, taking the Cd^II atoms as nodes and the μ‐aqua and μ‐bpe ligands as linkers, the two‐dimensional structure can be simplified as a (6,3) network.     

Poly[bis(μ‐benzene‐1,4‐dicarboxylato)bis[μ‐6‐(4‐pyridyl)‐5H‐imidazolo[4,5‐f][1,10]phenanthroline]dilead(II)]: an interpenetrating α‐Po net

The asymmetric unit of the title compound, [Pb₂(C₈H₄O₄)₂(C₁₈H₁₁N₅)₂]_n, contains two Pb^II atoms, two benzene‐1,4‐dicarboxylate (1,4‐bdc) dianions and two 6‐(4‐pyridyl)‐5H‐imidazolo[4,5‐f][1,10]phenanthroline (L) ligands. Each Pb^II atom is eight‐coordinated by three N atoms from two different L ligands and five carboxylate O atoms from three different 1,4‐bdc dianions. The two 1,4‐bdc dianions (1,4‐bdc₁ and 1,4‐bdc₂) show different coordination modes. Each 1,4‐bdc₁ coordinates to two Pb^II atoms in a chelating bis‐bidentate mode. Each carboxylate group of the 1,4‐bdc₂ anion connects two Pb^II atoms in a chelating–bridging tridentate mode to form a dinuclear unit. Neighbouring dinuclear units are connected together by the aromatic backbone of the 1,4‐bdc dianions and the L ligands into a three‐dimensional six‐connected α‐polonium framework. The most striking feature is that two identical three‐dimensional single α‐polonium nets are interlocked with each other, thus leading directly to the formation of a twofold interpenetrated three‐dimensional α‐polonium architecture. The framework is held together in part by strong N—H...O hydrogen bonds between the imidazole NH groups of the L ligands and the carboxylate O atoms of 1,4‐bdc dianions within different α‐polonium nets.     

Bis(μ‐benzene‐1,2‐dicarboxylato)bis{aqua[2‐(2‐chloro‐6‐fluorophenyl)‐1H‐imidazo[4,5‐f][1,10]phenanthroline]cadmium(II)} and its zinc(II) analogue

In the isomorphous title compounds, [Cd₂(C₈H₄O₄)₂(C₁₉H₁₀ClFN₄)₂(H₂O)₂] and [Zn₂(C₈H₄O₄)₂(C₁₉H₁₀ClFN₄)₂(H₂O)₂], the Cd^II centre is seven‐coordinated by two N atoms from one [2‐(2‐chloro‐6‐fluorophenyl)‐1H‐imidazo[4,5‐f][1,10]phenanthroline (L) ligand, one water O atom and four carboxylate O atoms from two different benzene‐1,2‐dicarboxylate (1,2‐bdc) ligands in a distorted pentagonal–bipyramidal coordination, while the Zn^II centre is six‐coordinated by two N atoms from one L ligand, one water O atom and three carboxylate O atoms from two different 1,2‐bdc ligands in a distorted octahedral coordination. Each pair of adjacent metal centres is bridged by two 1,2‐bdc ligands to form a dimeric structure. In the dimer, each L ligand coordinates one metal centre. The dimer is centrosymmetric, with a crystallographic inversion centre midway between the two metal centres. The aromatic interactions lead the dimers to form a two‐dimensional supramolecular architecture. Finally, O—H...O and N—H...O hydrogen bonds reinforce the two‐dimensional structures of the two compounds.     

Poly[[tetraaquabis(μ2‐2‐nitroterephthalato‐κ3O1:O4,O4′)(μ2‐piperazine‐κ3N:N′)dicadmium(II)] dihydrate]

In the title complex, {[Cd₂(C₈H₃NO₆)₂(C₄H₁₀N₂)(H₂O)₄]·2H₂O}_n, the Cd^II atoms show distorted octahedral coordination. The two carboxylate groups of the dianionic 2‐nitroterephthalate ligand adopt monodentate and 1,2‐bridging modes. The piperazine molecule is in a chair conformation and lies on a crystallographic inversion centre. The Cd^II atoms are connected via three O atoms from two carboxylate groups and two N atoms from piperazine molecules to form a two‐dimensional macro‐ring layer structure. These layers are further aggregated to form a three‐dimensional structure via rich intra‐ and interlayer hydrogen‐bonding networks. This study illustrates that, by using the labile Cd^II salt and a combination of 2‐nitroterephthalate and piperazine as ligands, it is possible to generate interesting metal–organic frameworks with rich intra‐ and interlayer O—H...O hydrogen‐bonding networks.     

Poly[diaqua(μ4‐benzene‐1,2‐dicarboxylato)(isonicotinato‐κ2O,O′)gadolinium(III)]

The title neutral polymer, [Gd(C₆H₄NO₂)(C₈H₄O₄)(H₂O)₂]_n, contains an extended two‐dimensional wave‐like lanthanide carboxylate layer decorated by isonicotinate (IN) ligands. The Gd^II atom is eight‐coordinated by four carboxylate O atoms from four benzene‐1,2‐dicarboxylate (1,2‐bdc) ligands, two 1,2‐bdc carboxylate O atoms from one chelating IN ligand and two terminal water molecules, forming a bicapped trigonal–prismatic coordination geometry. The wave‐like layers are stacked in an …ABAB… packing mode along the c‐axis direction. Strong hydrogen‐bonding interactions further stabilize the structure of the title compound.     

Poly[(N,N‐dimethylformamide‐κO)(μ3‐4,4′‐ethylenedibenzoato‐κ5O,O′:O′:O′′,O′′′)(pyrazino[2,3‐f][1,10]phenanthroline‐κ2N8,N9)lead(II)]

In the title Pb^II coordination polymer, [Pb(C₁₆H₁₀O₄)(C₁₄H₈N₄)(C₃H₇NO)]_n, each Pb^II atom is eight‐coordinated by two chelating N atoms from one pyrazino[2,3‐f][1,10]phenanthroline (L) ligand, one dimethylformamide (DMF) O atom and five carboxylate O atoms from three different 4,4′‐ethylenedibenzoate (eedb) ligands. The eedb dianions bridge neighbouring Pb^II centres through four typical Pb—O bonds and one longer Pb—O interaction to form a two‐dimensional structure. The C atoms from the L and eedb ligands form C—H...O hydrogen bonds with the O atoms of eedb and DMF ligands, which further stabilize the structure. The title compound is the first Pb^II coordination polymer incorporating the L ligand.     

Poly[(μ2‐aqua‐κ2O:O)(μ3‐azido‐κ3N1:N1:N3)(μ2‐isonicotinato‐κ2O:O′)lead(II)]

In the title compound, [Pb(C₆H₄NO₂)(N₃)(H₂O)]_n, the Pb ion is seven‐coordinated by three N atoms from three azide ligands, two O atoms from two isonicotinate (inic) ligands and two O atoms from two coordinated water molecules, forming a distorted monocapped triangular prismatic coordination geometry. Each azide ligand bridges three Pb^II ions in a μ_1,1,3 coordination mode to form a two‐dimensional three‐connected 6³ topology network extending in the bc plane. The carboxylate group of the inic unit and the aqua ligand act as coligands to bridge Pb^II ions. Adjacent two‐dimensional layers are connected by hydrogen‐bonding interactions between the isonicotinate N atom and the water molecule, resulting in an extended three‐dimensional network. The title complex is the first reported coordination polymer involving a p‐block metal, an azide and a carboxylate.     

catena‐Poly­[[di­aqua­cadmium(II)]‐μ‐5‐carboxyimidazole‐4‐carboxylato‐κ4N1,O5:O4,N3]

A new cadmium coordination polymer, [Cd(C₅H₂N₂O₄)(H₂O)₂]_n, possesses a one‐dimensional zigzag chain structure built from Cd^II centers bridged sequentially by pairs of O and N atoms of the 5‐carboxyimidazole‐4‐carboxylate ligand. The Cd^II center is in a distorted octahedral geometry, being coordinated by two O atoms from two coordinated water mol­ecules [Cd—O = 2.322 (7) and 2.364 (7) Å], and by two N atoms [Cd—N = 2.222 (6) and 2.232 (6) Å] and two carboxyl O atoms [Cd—O = 2.383 (6) and 2.414 (6) Å] from two 5‐carboxyimidazole‐4‐carboxylate ligands.     

Poly[[aqua(4,4′‐diazenediyldibenzoato‐κ4O,O′:O′′,O′′′)cadmium(II)]: a twofold interpenetrated three‐dimensional coordination polymer of PtS topology

In the title coordination compound, [Cd(C₁₄H₈N₂O₄)(H₂O)]_n, the Cd^II cation and the coordinated water molecule lie on a twofold axis, whereas the ligand lies on an inversion center. The Cd^II center is five‐coordinated in a distorted square‐pyramidal geometry by four carboxylate O atoms from four different 4,4′‐diazenediyldibenzoate (ddb) anions and one water O atom. The three‐dimensional frameworks thus formed by the bridging ddb anions interpenetrate to generate a three‐dimensional PtS‐type network. Additionally, the coordination water molecule and the carboxylate O atom form a hydrogen‐bonding interaction, stabilizing the three‐dimensional framework structure.     

A three‐dimensional cadmium(II) coordination polymer: poly[[[μ‐4,4′‐(propane‐1,3‐diyl)dipyridine‐κ2N:N](μ‐3,3′‐thiodipropionato‐κ3O,O′:O)cadmium(II)] monohydrate]

In the title coordination polymer, {[Cd(C₆H₈O₄S)(C₁₃H₁₄N₂)]·H₂O}_n, the Cd^II atom displays a distorted octahedral coordination, formed by three carboxylate O atoms and one S atom from three different 3,3′‐thiodipropionate ligands, and two N atoms from two different 4,4′‐(propane‐1,3‐diyl)dipyridine ligands. The Cd^II centres are bridged through carboxylate O atoms of 3,3′‐thiodipropionate ligands and through N atoms of 4,4′‐(propane‐1,3‐diyl)dipyridine ligands to form two different one‐dimensional chains, which intersect to form a two‐dimensional layer. These two‐dimensional layers are linked by S atoms of 3,3′‐thiodipropionate ligands from adjacent layers to form a three‐dimensional network.     

The two‐dimensional coordination polymer poly[diaqua(μ2‐1H‐imidazo[4,5‐f][1,10]phenanthroline)‐μ4‐sulfato‐μ3‐sulfato‐dicadmium(II)]

In the title coordination polymer, [Cd₂(SO₄)₂(C₁₃H₈N₄)(H₂O)₂]_n, there are two crystallographically independent Cd^II centres with different coordination geometries. The first Cd^II centre is hexacoordinated by four O atoms of four sulfate ligands, one water O atom and one N atom of a 1H‐imidazo[4,5‐f][1,10]phenanthroline (IP) ligand, giving a distorted octahedral coordination environment. The second Cd^II centre is heptacoordinated by four O atoms of three sulfate ligands, one water O atom and two N atoms of one chelating IP ligand, resulting in a distorted monocapped anti‐trigonal prismatic geometry. The symmetry‐independent Cd^II ions are bridged in an alternating fashion by sulfate ligands, forming one‐dimensional ladder‐like chains which are connected through the IP ligands to form two‐dimensional layers. These two‐dimensional layers are linked by interlayer hydrogen bonds, leading to the formation of a three‐dimensional supramolecular network.     

catena‐Poly[[aquacopper(II)]‐μ‐hydroxido‐μ‐naphthalene‐1‐carboxylato‐κ2O:O′]: effect of a bulky aromatic skeleton in self‐assembly

In the title coordination polymer, [Cu(C₁₁H₇O₂)(OH)(H₂O)]_n, the Cu^II center is five‐coordinated by two O atoms from two different naphthalene‐1‐carboxylate (L) ligands, one O atom from one coordinated water molecule and two O atoms from two hydroxide anions. L ligands and hydroxide anions jointly bridge adjacent Cu^II centers to generate a one‐dimensional chain along the b‐axis direction. The results reveal that the steric bulk of the naphthalene ring system in L may play an important role in the formation of the title complex.     

A two‐dimensional cadmium(II) coordination polymer based on 5‐(pyridin‐4‐yl)isophthalic acid: poly[[tetraaquabis[μ3‐5‐(pyridin‐4‐yl)isophthalato]dicadmium(II)] pentahydrate]

The title Cd^II compound, {[Cd₂(C₁₃H₇NO₄)₂(H₂O)₄]·5H₂O}_n, was synthesized by the hydrothermal reaction of Cd(NO₃)₂·4H₂O and 5‐(pyridin‐4‐yl)isophthalic acid (H₂L). The asymmetric unit contains two crystallographically independent Cd^II cations, two deprotonated L²⁻ ligands, four coordinated water molecules and five isolated water molecules. One of the Cd^II cations adopts a six‐coordinate octahedral coordination geometry involving three O atoms from one bidentate chelating and one monodentate carboxylate group of two different L²⁻ ligands, one N atom of another L²⁻ ligand and two coordinated water molecules. The second Cd^II cation adopts a seven‐coordinate pentagonal–bipyramidal coordination geometry involving four O atoms from two bidentate chelating carboxylate groups of two different L²⁻ ligands, one N atom of another L²⁻ ligand and two coordinated water molecules. Each L²⁻ ligand bridges three Cd^II cations and, likewise, each Cd^II cation connects to three L²⁻ ligands, giving rise to a two‐dimensional graphite‐like 6³ layer structure. These two‐dimensional layers are further linked by O—H...O hydrogen‐bonding interactions to form a three‐dimensional supramolecular architecture. The photoluminescence properties of the title compound were also investigated.     

catena‐Poly[[[cis‐aqua­bis(4‐carboxy­cyclo­hexane‐1‐carboxyl­ato‐κ2O,O′)cadmium(II)]‐μ‐4,4′‐bipyridine‐κ2N:N] monohydrate]

The title complex, {[Cd(C₈H₁₁O₄)₂(C₁₀H₈N₂)(H₂O)]·H₂O}_n, consists of linear chains formed through 4,4′‐bipyridine ligands linking seven‐coordinated Cd^II ions. Each Cd^II ion is in a distorted penta­gonal–bipyramidal environment, coordinated by one water ligand, two 4‐carboxy­cyclo­hexane‐1‐carboxyl­ate ligands and one bridging 4,4′‐bipyridine ligand to generate linear chains. The water mol­ecules and the Cd atom on one side, and the 4,4′‐bipyridine unit on the other, are bisected by two sets of twofold axes. The carboxylate group of the 4‐carboxy­cyclo­hexane‐1‐carboxyl ligand chelates a Cd^II ion, while the (protonated) carboxyl group forms hydrogen bonds with adjacent chains, resulting in a layered structure. This is the first reported occurrence of a dicarboxycyclo­hexane ligand exhibiting a non‐bridging coordination mode.     

A one‐dimensional coordination polymer based on Cd2O2 clusters: poly[aqua(μ3‐4,4′‐sulfonyldibenzoato)(3,4,7,8‐tetramethyl‐1,10‐phenanthroline‐κ2N,N′)cadmium(II)]

In the title mixed‐ligand metal–organic polymeric complex [Cd(C₁₄H₈O₆S)(C₁₆H₁₆N₂)(H₂O)]_n, the asymmetric unit contains a crystallographically unique Cd^II atom, one doubly deprotonated 4,4′‐sulfonyldibenzoic acid ligand (H₂SDBA), one 3,4,7,8‐tetramethyl‐1,10‐phenanthroline (TMPHEN) molecule and one water molecule. Each Cd^II centre is coordinated by two N atoms from the chelating TMPHEN ligand, three O atoms from monodentate carboxylate groups of three different SDBA²⁻ ligands and one O atom from a coordinated water molecule, giving a distorted CdN₂O₄ octahedral geometry. Single‐crystal X‐ray diffraction analysis reveals that the compound is a one‐dimensional double‐chain polymer containing 28‐membered rings based on Cd₂O₂ clusters, with a Cd...Cd separation of 3.6889 (4) Å. These chains are linked by O—H...O and C—H...O hydrogen bonds to form a three‐dimensional supramolecular framework. The framework is reinforced by π–π and C—O...π interactions.     

Poly[[triaquazinc(II)]‐μ3‐4‐nitrophthalato‐κ3O1:O2:O2′]

In the title complex, [Zn(C₈H₃NO₆)(H₂O)₃]_n, the two carboxylate groups of the 4‐nitrophthalate dianion ligands have monodentate and 1,3‐bridging modes, and Zn atoms are interconnected by three O atoms from the two carboxylate groups into a zigzag one‐dimensional chain along the b‐axis direction. The Zn atom shows distorted octahedral coordination as it is bonded to three O atoms from carboxylate groups of three 4‐nitrophthalate ligands and to three O atoms of three non‐equivalent coordinated water molecules. The one‐dimensional chains are aggregated into two‐dimensional layers through inter‐chain hydrogen bonding. The whole three‐dimensional structure is further maintained and stabilized by inter‐layer hydrogen bonds.     

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.     

A new one‐dimensional nickel metal–organic framework: catena‐poly[[[diaquabis(4‐{[(1‐phenyl‐1H‐tetrazol‐5‐yl)sulfanyl]methyl}benzoato‐κO)nickel(II)]‐μ‐4,4′‐bipyridine‐κ2N:N′] monohydrate]

The title complex, {[Ni(C₁₅H₁₁N₄O₂S)₂(C₁₀H₈N₂)(H₂O)₂]·H₂O}_n, was synthesized by the reaction of nickel chloride, 4‐{[(1‐phenyl‐1H‐tetrazol‐5‐yl)sulfanyl]methyl}benzoic acid (HL) and 4,4′‐bipyridine (bpy) under hydrothermal conditions. The asymmetric unit contains two half Ni^II ions, each located on an inversion centre, two L⁻ ligands, one bpy ligand, two coordinated water molecules and one unligated water molecule. Each Ni^II centre is six‐coordinated by two monodentate carboxylate O atoms from two different L⁻ ligands, two pyridine N atoms from two different bpy ligands and two terminal water molecules, displaying a nearly ideal octahedral geometry. The Ni^II ions are bridged by 4,4′‐bipyridine ligands to afford a linear array, with an Ni...Ni separation of 11.361 (1) Å, which is further decorated by two monodentate L⁻ ligands trans to each other, resulting in a one‐dimensional fishbone‐like chain structure. These one‐dimensional fishbone‐like chains are further linked by O—H...O, O—H...N and C—H...O hydrogen bonds and π–π stacking interactions to form a three‐dimensional supramolecular architecture. The thermal stability of the title complex was investigated via thermogravimetric analysis.