Crystal structure and characterization of a new one-dimensional copper(II) coordination polymer containing a 4-amino-benzoic acid ligand

A CuII coordination polymer, catena-poly[[[aqua-copper(II)]-bis-(μ-4-amino-benz-o-ato)-κ2 N:O;κ2 O:N] monohydrate], {[Cu(pABA)2(H2O)]·H2O}n (pABA = p-amino-benzoate, C7H4NO2 -), was synthesized and characterized. It exhibits a one-dimensional chain structure extended into a three-dimensional supra-molecular assembly through hydrogen bonds and π-π inter-actions. While the twinned crystal shows a metrically ortho-rhom-bic lattice and an apparent space group Pbcm, the true symmetry is monoclinic (space group P2/c), with disordered Cu atoms and mixed roles of water mol-ecules (aqua ligand/crystallization water). The luminescence spectrum of the complex shows an emission at 345 nm, cf. 349 nm for pABAH.

Interplay of Anisotropic Exchange Interactions and Single-Ion Anisotropy in Single-Chain Magnets Built from Ru/Os Cyanidometallates(III) and Mn(III) Complex

Two novel 1D heterobimetallic compounds {[Mn^III(SB²⁺)M^III(CN)₆]·4H₂O}_n (SB²⁺ = N,N'-ethylenebis(5-trimethylammoniomethylsalicylideneiminate) based on orbitally degenerate cyanidometallates [Os^III(CN)₆]^3- (1) and [Ru^III(CN)₆]^3- (2) and Mn^III Schiff base complex were synthesized and characterized structurally and magnetically. Their crystal structures consist of electrically neutral, well-isolated chains composed of alternating [M^III(CN)₆]^3- anions and square planar [Mn^III(SB²⁺)]³⁺ cations bridged by cyanide groups. These -ion magnetic anisotropy of Mn^III centers. These results indicate that the presence of compounds exhibit single-chain magnet (SCM) behavior with the energy barriers of Δτ₁/k_B = 73 K, Δτ₂/k_B = 41.5 K (1) and Δτ₁/k_B = 51 K, Δτ₂ = 27 K (2). Blocking temperatures of T_B = 2.8, 2.1 K and magnetic hysteresis with coercive fields (at 1.8 K) of 8000, 1600 Oe were found for 1 and 2, respectively. Theoretical analysis of the magnetic data reveals that their single-chain magnet behavior is a product of a complicated interplay of extremely anisotropic triaxial exchange interactions in M^III(4d/5d)-CN-Mn^III fragments: -J_xS_M^xS_Mn^x-J_yS_M^yS_Mn^y-J_zS_M^zS_Mn^z, with opposite sign of exchange parameters J_x = -22, J_y = +28, J_z = -26 cm^-1 and J_x = -18, J_y = +20, J_z = -18 cm^-1 in 1 and 2, respectively) and single orbitally degenerate [Os^III(CN)₆]^3- and [Ru^III(CN)₆]^3- spin units with unquenched orbital angular momentum in the chain compounds 1 and 2 leads to a peculiar regime of slow magnetic relaxation, which is beyond the scope of the conventional Glaubers's 1D Ising model and anisotropic Heisenberg model.

One- and two-dimensional PbII compounds resulting from reaction of PbBr2 and Pb(SCN)2 with pyrimidine-2-thione

Pyrimidine-2-thione (HSpym) reacts with lead(II) thiocyanate and lead(II) bromide in N,N-dimethylformamide (DMF) to form poly[(μ-isothiocyanato-κ²N:S)(μ₄-pyrimidine-2-thiolato-κ⁶N¹,S:S:S:S,N³)lead(II)], [Pb(C₄H₃N₂S)(NCS)]_n or [Pb(Spym)(NCS)]_n, (I), and the polymeric one-dimensional (1D) compound catena-poly[[μ₄-bromido-di-μ-bromido-(μ-pyrimidine-2-thiolato-κ³N¹,S:S)(μ-pyrimidine-2-thione-κ³N¹,S:S)dilead(II)] N,N-dimethylformamide monosolvate], {[Pb₂Br₃(C₄H₃N₂S)(C₄H₄N₂S)]·C₃H₇NO}_n or {[Pb₂Br₃(Spym)(HSpym)]·DMF}_n, (IIa), respectively. Poly[μ₄-bromido-di-μ₃-bromido-(μ-pyrimidine-2-thiolato-κ³N¹,S:S)(μ-pyrimidine-2-thione-κ³N¹,S:S)dilead(II)], [Pb₂Br₃(C₄H₃N₂S)(C₄H₄N₂S)]_n or [Pb₂Br₃(Spym)(HSpym)]_n, (IIb), could be obtained as a mixture with (IIa) when using a lesser amount of solvent. In the crystal structures of the pseudohalide/halide Pb^II stable compounds, coordination of anionic and neutral HSpym has been observed. Both Spym^- (in the thiolate tautomeric form) and NCS^- ligands were responsible for the two-dimensional (2D) arrangement in (I). The Br^- ligands establish the 1D polymeric arrangement in (IIa). Eight-coordinated metal centres have been observed in both compounds, when considering the Pb...S and Pb...Br interactions. Both compounds were characterized by FT-IR and diffuse reflectance spectroscopies, as well as by powder X-ray diffraction. Compound (IIa) and its desolvated version (IIb) represent the first structurally characterized Pb^II compounds containing neutral HSpym and anionic Spym^- ligands. After a prolonged time in solution, (IIa) is converted to another compound due to complete deprotonation of HSpym. The structural characterization of (I) and (II) suggests HSpym as a good candidate for the removal of Pb^II ions from solutions containing thiocyanate or bromide ions.

A one-dimensional manganese(III)-porphyrin coordination polymer: crystal structure and photophysical properties

A novel manganese(III)-porphyrin complex, namely, catena-poly[[chloridomanganese(III)]-μ₂-5,10,15,20-tetrakis(pyridin-3-yl)-21H,23H-porphinato(2-)-κ⁵N²¹,N²²,N²³,N²⁴:N⁵], [MnCl(C₄₀H₂₄N₈)]_n, 1, was prepared by the hydrothermal reaction of manganese chloride with 5,10,15,20-tetrakis(pyridin-3-yl)-21H,23H-porphine. The crystal structure was determined by single-crystal X-ray diffraction. The porphyrin macrocycle exhibits a saddle-like distortion geometry. The Mn^III atom has a six-coordination geometry. Each porphyrin unit links to two neighbouring units to yield a one-dimensional coordination polymer. These chains are further interlinked by hydrogen bonds to form a two-dimensional network. The complex shows red photoluminescence emission bands in ethanol solution, which can be attributed to ligand-to-ligand charge transfer (LLCT) accompanied by partial metal-to-ligand charge transfer (MLCT), as revealed by TDDFT calculations.

A new photoluminescent coordination polymer constructed with an N-donor ligand having extended coordination capabilities derived from quinoline and pyridine

Employment of the organic 2-(pyridin-4-yl)quinoline-4-carboxylic acid ligand with extended coordination capabilities leads to the formation of the one-dimensional copper(II) coordination polymer catena-poly[[diaquacopper(II)]-bis[μ-2-(pyridin-4-yl)quinoline-4-carboxylato]-κ²N²:O;κ²O:N], {[Cu(C₁₅H₉N₂O₂)₂(H₂O)₂]·2H₂O}_n, under hydrothermal conditions. The ligand, isolated as its hydrochloride salt, namely, 4-(4-carboxyquinolin-2-yl)pyridinium chloride monohydrate, C₁₅H₁₁N₂O₂⁺·Cl^-·H₂O, reveals a pseudosymmetry element (translation a/2) in its crystal structure. The additional pyridyl N atom, in comparison with the previously reported analogues with an arene ring instead of the pyridyl ring in the present ligand molecule, promotes the formation of a one-dimensional coordination polymer, rather than discrete molecules. This polymer shows photoluminescent properties with bathochromic/hypsochromic shifts of the ligand absorption bands, leading to a single band at 479 nm. The Cu^II ions are involved in weak antiferromagnetic interactions within dimeric units, as evidenced by SQUID magnetometry.

One-pot concomitant preparation of two copper(II) coordination polymers with different configurations of bridging bithiophene ligands

By employing the conjugated bithiophene ligand 5,5'-bis(1H-imidazol-1-yl)-2,2'-bithiophene (bibp), which can exhibit trans and cis conformations, two different Cu^II coordination polymers, namely, poly[[μ-5,5'-bis(1H-imidazol-1-yl)-2,2'-bithiophene-κ²N:N'](μ₂-4,4'-oxydibenzoato-κ²O:O')copper(II)], [Cu(C₁₄H₈O₅)(C₁₄H₁₀N₄S₂)]_n or [Cu(bibp)(oba)]_n, (I), and catena-poly[μ-aqua-bis[μ-5,5'-bis(1H-imidazol-1-yl)-2,2'-bithiophene-κ²N:N']bis(μ₃-4,4'-oxydibenzoato)-κ³O:O':O'';κ⁴O:O',O'':O'-dicopper(II)], [Cu₂(C₁₄H₈O₅)₂(C₁₄H₁₀N₄S₂)(H₂O)]_n or [Cu₂(bibp)(oba)₂(H₂O)]_n, (II), have been prepared through one-pot concomitant crystallization and characterized by single-crystal X-ray diffraction, IR spectroscopy, elemental analysis, powder X-ray diffraction (PXRD) and thermogravimetric (TG) analysis. Single-crystal X-ray diffraction indicates that the most interesting aspect of the structure is the existence of sole trans and cis conformations of the bibp ligand in a single net of (I) and (II), respectively. Compound (I) displays a threefold interpenetrating three-dimensional framework with a 4-connected {6⁵.8} cds topology, whereas (II) features a one-dimensional chain structure. In the crystal of (II), the polymeric chains are further extended through C-H...O hydrogen bonds and C-H...π interactions into a three-dimensional supramolecular architecture. In addition, strong intramolecular O-H...O hydrogen bonds formed between the bridging water molecules and the carboxylate O atoms improve the stability of the framework of (II). Furthermore, solid-state UV-Vis spectroscopy experiments show that compounds (I) and (II) exhibit optical band gaps which are characteristic for optical semiconductors, with values of 2.70 and 2.26 eV, respectively.

Crystal structure and photoluminescence properties of catena-poly[[bis-(1-benzyl-1H-imidazole-κN 3)cadmium(II)]-di-μ-azido-κ4 N 1:N 3]

The crystal structure and photoluminescence properties of a new one-dimensional Cd^II coordination polymer constructued by azide and 1-benzyl­imidazole (bzi) are reported.

The new title one-dimensional Cd^II coordination polymer, [Cd(C₁₀H₁₀N₂)₂(μ_1,3-N₃)₂]_n, has been synthesized and structurally characterized by single-crystal X-ray diffraction. The asymmetric unit consists of a Cd^II ion, one azide and one 1-benzyl­imidazole (bzi) ligand. The Cd^II ion is located on an inversion centre and is surrounded in a distorted octa­hedral coordination sphere by six N atoms from four symmetry-related azide ligands and two symmetry-related bzi ligands. The Cd^II ions are linked by double azide bridging ligands within a μ_1,3-N₃ end-to-end (EE) coordination mode, leading to a one-dimensional linear structure extending parallel to [100]. The supra­molecular framework is stabilized by the presence of weak C—H⋯N inter­actions, π–π stacking [centroid-to-centroid distance of 3.832 (2) Å] and C—H⋯π inter­actions between neighbouring chains.

A cyanide-bridged FeIII-MnII heterobimetallic one-dimensional coordination polymer: synthesis, crystal structure, experimental and theoretical magnetism investigation

A new cyanide-bridged Fe^III-Mn^II heterobimetallic coordination polymer (CP), namely catena-poly[[[N,N'-(1,2-phenylene)bis(pyridine-2-carboxamidato)-κ⁴N,N',N'',N''']iron(III)]-μ-cyanido-κ²C:N-[bis(4,4'-bipyridine-κN)bis(methanol-κO)manganese(II)]-μ-cyanido-κ²N:C], {[FeMn(C₁₈H₁₂N₄O₂)(CN)₂(C₁₀H₈N₂)₂(CH₃OH)₂]ClO₄}_n, (1), was prepared by the self-assembly of the trans-dicyanidoiron(III)-containing building block [Fe(bpb)(CN)₂]^- [bpb^2- = N,N'-(1,2-phenylene)bis(pyridine-2-carboxamidate)], [Mn(ClO₄)₂]·6H₂O and 4,4'-bipyridine, and was structurally characterized by elemental analysis, IR spectroscopy, single-crystal X-ray crystallography and powder X-ray diffraction (PXRD). Single-crystal X-ray diffraction analysis shows that CP 1 possesses a cationic linear chain structure consisting of alternating cyanide-bridged Fe-Mn units, with free perchlorate as the charge-balancing anion, which can be further extended into a two-dimensional supramolecular sheet structure via inter-chain π-π interactions between the 4,4'-bipyridine ligands. Within the chain, each Mn^II ion is six-coordinated by an N₆ unit and is involved in a slightly distorted octahedral coordination geometry. Investigation of the magnetic properties of 1 reveals an antiferromagnetic coupling between the cyanide-bridged Fe^III and Mn^II ions. A best fit of the magnetic susceptibility based on the one-dimensional alternating chain model leads to the magnetic coupling constants J₁ = -1.35 and J₂ = -1.05 cm^-1, and the antiferromagnetic coupling was further confirmed by spin Hamiltonian-based density functional theoretical (DFT) calculations.

ACr(C2O4)2(H2O)4 (A = Li or Na): two new coordination polymers of low dimensionality with different hydrogen-bond networks

Single crystals of two new bimetallic oxalate compounds with the formula [ACr(C₂O₄)₂(H₂O)₄]_n (A = Li or Na), namely catena-poly[[diaqualithium(I)]-μ-oxalato-κ⁴O¹,O²:O^1',O^2'-[diaquachromium(III)]-μ-oxalato-κ⁴O¹,O²:O^1',O^2'], (I), and catena-poly[[diaquasodium(I)]-μ-oxalato-κ⁴O¹,O²:O^1',O^2'-[di-aquachromium(III)]-μ-oxalato-κ⁴O¹,O²:O^1',O^2'], (II), have been synthesized, characterized and their crystal structures elucidated by X-ray diffraction analysis and compared. The compounds crystallize in the monoclinic space group C2/m for (I) and in the triclinic space group P-1 for (II); however, they have somewhat similar features. In the asymmetric unit of (I), the Li and Cr atoms both have space-group-imposed 2/m site symmetry, while only half of the oxalate ligand is present and two independent water molecules lie on the mirror plane. The water O atoms around the Li atom are disordered over two equivalent positions separated by 0.54 (4) Å. In the asymmetric unit of (II), the atoms of one C₂O₄^2- ligand and two independent water molecules are in general positions, and the Na and Cr atoms lie on an inversion centre. Taking into account the symmetry sites of both metallic elements, the unit cells may be described as pseudo-face-centred monoclinic for (I) and as pseudo-centred triclinic for (II). Both crystal structures are comprised of one-dimensional chains of alternating trans-Cr(CO)₄(H₂O)₂ and trans-A(CO)₄(H₂O)₂ units μ₂-bridged by bis-chelating oxalate ligands. The resulting linear chains are parallel to the [101] direction for (I) and to the [11-1] direction for (II). Within the two coordination polymers, strong hydrogen bonds result in tetrameric R₄⁴(12) synthons which link the metal chains, thus leading to two-dimensaional supramolecular architectures. The two structures differ from each other with respect to the symmetry relations inside the ligand, the role of electrostatic forces in the crystal structure and the molecular interactions of the hydrogen-bonded networks. Moreover, they exhibit the same UV-Vis pattern typical of a Cr^III centrosymmetric geometry, while the IR absorption shows some differences due to the oxalate-ligand conformation. Polymers (I) and (II) are also distinguished by a different behaviours during the decomposition process, the precursor (I) leading to the oxide LiCrO₂, while the residues of (II) consist of a mixture of sodium carbonate and Cr^III oxide.

Structural characterization of a hybrid terpyridine-pyrazine ligand and its one-dimensional ZnII coordination polymer: a computational approach to conventional and nonconventional intermolecular interactions

The structures of a new hybrid terpyridine-pyrazine ligand, namely 4'-[4-(pyrazin-2-yl)phenyl]-4,2':6',4''-terpyridine (L2), C₂₅H₁₇N₅, and its one-dimensional coordination polymer catena-poly[[bis(acetylacetonato-κ²O,O')zinc]-μ-4'-[4-(pyrazin-2-yl-κN⁴)phenyl]-4,2':6',4''-terpyridine-κN¹], [Zn(C₅H₇O₂)₂(C₂₅H₁₇N₅)]_n or [Zn(acac)₂(L2)]_n (Hacac is acetylacetone), are reported. Packing interactions in both crystal structures are analyzed using Hirshfeld surface and enrichment ratio techniques. For the simpler structure of the monomeric ligand, further studies on the interaction hierarchy using the energy framework approach were made. The result was a complete picture of the intermolecular interaction landscape, which revealed some subtle details, for example, that some weak (at first sight negligible) C-H...N interactions in the structure of free L2 play a relevant role in the crystal stabilization.

Effect of pH on the construction of CdII coordination polymers involving the 1,1'-[1,4-phenylenebis(methylene)]bis(3,5-dicarboxylatopyridinium) ligand

Changing the pH value of a reaction system can result in polymers with very different compositions and architectures. Two new coordination polymers based on 1,1'-[1,4-phenylenebis(methylene)]bis(3,5-dicarboxylatopyridinium) (L^2-), namely catena-poly[[[tetraaquacadmium(II)]-μ₂-1,1'-[1,4-phenylenebis(methylene)]bis(3,5-dicarboxylatopyridinium)] 1.66-hydrate], {[Cd(C₂₂H₁₄N₂O₈)(H₂O)₄]·1.66H₂O}_n, (I), and poly[{μ₆-1,1'-[1,4-phenylenebis(methylene)]bis(3,5-dicarboxylatopyridinium)}cadmium(II)], [Cd(C₂₂H₁₄N₂O₈)]_n, (II), have been prepared in the presence of NaOH or HNO₃ and structurally characterized by single-crystal X-ray diffraction. In polymer (I), each Cd^II ion is coordinated by two halves of independent L^2- ligands, forming a one-dimensional chain structure. In the crystal, these chains are further connected through O-H...O hydrogen bonds, leading to a three-dimensional hydrogen-bonded network. In polymer (II), each hexadentate L^2- ligand coordinates to six Cd^II ions, resulting in a three-dimensional network structure, in which all of the Cd^II ions and L^2- ligands are equivalent, respectively. The IR spectra, thermogravimetric analyses and fluorescence properties of both reported compounds were investigated.

Coordination polymers of CdII and PbII with croconate show remarkable differences in coordination patterns: a structural and spectroscopic study

The croconate dianion is a highly versatile ligand with two tautomeric forms making it useful for building large superstructures in the solid state. The single-crystal X-ray structures of Pb^II- and Cd^II-croconate coordination polymers, namely catena-poly[[[diaqualead(II)]-μ-croconato-κ⁴O¹,O²:O³,O⁴] monohydrate], {[Pb(C₅O₅)(H₂O)₂]·H₂O}_n, 1, and catena-poly[[triaquacadmium(II)]-μ-croconato-κ⁴O¹,O²:O³,O⁴], [Cd(C₅O₅)(H₂O)₃]_n, 2, have been determined. Both polymers form one-dimensional (1D) structures; 1 is a nonplanar 1D zigzag coordination polymer extended along the crystallographic b axis, whereas 2 is a planar 1D ribbon parallel to the [101] direction. In 2, three H₂O molecules are coordinated directly to the metal atom, while in 1, only two H₂O molecules are directly coordinated to the metal atom. A third interstitial H₂O molecule is involved in hydrogen bonding with O atoms of the croconate ligands of an adjacent layer and other H₂O molecules, resulting in stacked double layers parallel to the [105] plane. Solid-state FT-IR and solution UV-Vis spectra also substantiate the croconate coordination.

Effects of two benzenedicarboxylic acids on the construction of CdII coordination polymers incorporating a flexible N-donor ligand

Compared with the monomorphic type of ligand, combining mixed ligands in one coordination polymer offers greater tunability of the structural framework. Employment of N-heterocyclic ligands and aromatic polycarboxylates is an effective approach for the construction of metal-organic frameworks (MOFs). Two new coordination polymers incorporating both 2-[(1H-imidazol-1-yl)methyl]-1H-benzimidazole (imb) and benzenedicarboxylic acid isomers, namely, catena-poly[[[di-μ-chlorido-bis[(2-carboxybenzoato-κ²O¹,O^1')cadmium(II)]]-bis{μ-2-[(1H-imidazol-1-yl)methyl]-1H-benzimidazole-κ²N:N'}] dihydrate], {[Cd(C₈H₅O₄)Cl(C₁₁H₁₀N₄)]·H₂O}_n, (I), and poly[[aqua(μ₂-benzene-1,3-dicarboxylato-κ³O¹,O^1':O³){μ₂-2-[(1H-imidazol-1-yl)methyl]-1H-benzimidazole-κ²N:N'}cadmium(II)] dihydrate], {[Cd(C₈H₄O₄)(C₁₁H₁₀N₄)(H₂O)]·2H₂O}_n, (II), have been prepared and structurally characterized by single-crystal X-ray diffraction. In polymer (I), imb ligands bridge Cd^II ions, forming a one-dimensional chain, and 2-carboxybenzoate anions coordinate to the Cd^II ions in a terminal fashion. Polymer (II) exhibits a two-dimensional network structure in which imb ligands and the benzene-1,3-dicarboxylate anions join Cd^II ions co-operatively. This indicates that changing of the aromatic dicarboxylic acids can result in polymers with different compositions and architectures. Moreover, their IR spectra, PXRD (powder X-ray diffraction) patterns, thermogravimetric analyses and fluorescence properties were also investigated.

One-dimensional copper(II) coordination polymers based on 1,3-bis(pyridin-4-yl)propane and diimine ligands

Two one-dimensional (1D) coordination polymers (CPs), namely catena-poly[[[aqua(2,2'-bipyridine-κ²N,N')(nitrato-κO)copper(II)]-μ-1,3-bis(pyridin-4-yl)propane-κ²N:N'] nitrate], {[Cu(NO₃)(C₁₀H₈N₂)(C₁₃H₁₄N₂)(H₂O)]·NO₃}_n (1), and catena-poly[[[aqua(nitrato-κO)(1,10-phenanthroline-κ²N,N')copper(II)]-μ-1,3-bis(pyridin-4-yl)propane-κ²N:N'] nitrate], {[Cu(NO₃)(C₁₂H₈N₂)(C₁₃H₁₄N₂)(H₂O)]·NO₃}_n (2), have been synthesized using [Cu(NO₃)(NN)(H₂O)₂]NO₃, where NN = 2,2'-bipyridine (bpy) or 1,10-phenanthroline (phen), as a linker in a 1:1 molar ratio. The CPs were characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis and single-crystal X-ray structure determination. The 1,3-bis(pyridin-4-yl)propane (dpp) ligand acts as a bridging ligand, leading to the formation of a 1D polymer. The octahedral coordination sphere around copper consists of two N atoms from bpy for 1 or phen for 2, two N atoms from dpp, one O atom from water and one O atom from a coordinated nitrate anion. Each structure contains two crystallographically independent chains in the asymmetric unit and the chains are linked via hydrogen bonds into a three-dimensional network.

More crystal field theory in action: the metal-4-picoline (pic)-sulfate [M(pic)x]SO4 complexes (M = Fe, Co, Ni, Cu, Zn, and Cd)

Seven crystal structures of five first-row (Fe, Co, Ni, Cu, and Zn) and one second-row (Cd) transition metal-4-picoline (pic)-sulfate complexes of the form [M(pic)_x]SO₄ are reported. These complexes are catena-poly[[tetrakis(4-methylpyridine-κN)metal(II)]-μ-sulfato-κ²O:O'], [M(SO₄)(C₆H₇N)₄]_n, where the metal/M is iron, cobalt, nickel, and cadmium, di-μ-sulfato-κ⁴O:O-bis[tris(4-methylpyridine-κN)copper(II)], [Cu₂(SO₄)₂(C₆H₇N)₆], catena-poly[[bis(4-methylpyridine-κN)zinc(II)]-μ-sulfato-κ²O:O'], [Zn(SO₄)(C₆H₇N)₂]_n, and catena-poly[[tris(4-methylpyridine-κN)zinc(II)]-μ-sulfato-κ²O:O'], [Zn(SO₄)(C₆H₇N)₃]_n. The Fe, Co, Ni, and Cd compounds are isomorphous, displaying polymeric crystal structures with infinite chains of M^II ions adopting an octahedral N₄O₂ coordination environment that involves four picoline ligands and two bridging sulfate anions. The Cu compound features a dimeric crystal structure, with the Cu^II ions possessing square-pyramidal N₃O₂ coordination environments that contain three picoline ligands and two bridging sulfate anions. Zinc crystallizes in two forms, one exhibiting a polymeric crystal structure with infinite chains of Zn^II ions adopting a tetrahedral N₂O₂ coordination containing two picoline ligands and two bridging sulfate anions, and the other exhibiting a polymeric crystal structure with infinite chains of Zn^II ions adopting a trigonal bipyramidal N₃O₂ coordination containing three picoline ligands and two bridging sulfate anions. The structures are compared with the analogous pyridine complexes, and the observed coordination environments are examined in relation to crystal field theory.

One-dimensional networks formed via the self-assembly of anthracenedibenzoic acid with zinc(II)

Self-assembly of metal-organic coordination polymers occurs because of enthalpically favorable interactions. In the case of the bulky 4,4'-(anthracene-9,10-diyl)dibenzoic acid ligand (abdH₂), we demonstrate that the presence of numerous π-π and C-H...π interactions outweigh the formation of saturated coordination complexes with zinc, leading to the formation of a dimethylformamide (DMF) solvate, namely 4,4'-(anthracene-9,10-diyl)dibenzoic acid dimethylformamide disolvate, C₂₈H₁₈O₄·2C₃H₇NO or [(abdH₂)(DMF)₂], at low concentrations of zinc. Meanwhile, at higher zinc concentrations, the abdH₂ ligand gives rise to the nonporous one-dimensional coordination polymer catena-poly[[bis(dimethylformamide-κO)zinc(II)]-μ-4,4'-(anthracene-9,10-diyl)dibenzoato-κ²O:O'], [Zn(C₂₈H₁₆O₄)(C₃H₇NO)₂]_n or [Zn(abd)(DMF)₂]_n, when assembled in dimethylformamide, while a related compound is observed when N,N-dimethylacetamide (DMA) is used as the solvent, namely catena-poly[[[bis(N,N-dimethylacetamide-κO)zinc(II)]-μ-4,4'-(anthracene-9,10-diyl)dibenzoato-κ²O:O'] N,N-dimethylacetamide monosolvate], {[Zn(C₂₈H₁₆O₄)(C₄H₉NO)₂]·C₄H₉NO}_n or {[Zn(abd)(DMA)₂]·DMA}_n. Attempts to use other amide-based solvents did not give rise to any other assembled structures.

A new one-dimensional CdII coordination polymer incorporating 2,2'-(1,2-phenylene)bis(1H-imidazole-4,5-dicarboxylate)

Imidazole-4,5-dicarboxylic acid (H₃IDC) and its derivatives are widely used in the preparation of new coordination polymers owing to their versatile bridging coordination modes and potential hydrogen-bonding donors and acceptors. A new one-dimensional coordination polymer, namely catena-poly[[diaquacadmium(II)]-μ₃-2,2'-(1,2-phenylene)bis(1H-imidazole-4,5-dicarboxylato)], [Cd(C₁₆H₆N₄O₈)_0.5(H₂O)₂]_n or [Cd(H₂Phbidc)_1/2(H₂O)₂]_n, has been synthesized by the reaction of Cd(OAc)₂·2H₂O (OAc is acetate) with 2,2'-(1,2-phenylene)bis(1H-imidazole-4,5-dicarboxylic acid) (H₆Phbidc) under solvothermal conditions. In the polymer, one type of Cd ion (Cd1) is six-coordinated by two N atoms and two O atoms from one H₂Phbidc^4- ligand and by two O atoms from two water molecules, forming a significantly distorted octahedral CdN₂O₄ coordination geometry. In contrast, the other type of Cd ion (Cd2) is six-coordinated by two N atoms and two O atoms from two symmetry-related H₂Phbidc^4- ligands and by two O atoms from two symmetry-related water molecules, leading to a more regular octahedral coordination geometry. The Cd1 and Cd2 ions are linked by H₂Phbidc^4- ligands into a one-dimensional chain which runs parallel to the b axis. In the crystal, the one-dimensional chains are connected through hydrogen bonds, generating a two-dimensional layered structure parallel to the ab plane. Adjacent layers are further linked by hydrogen bonds, forming a three-dimensional structure in the solid state.

Two new CoII coordination polymers with multifunctional 5-amino-2,4,6-tribromoisophthalic acid and flexible isomeric bis(imidazole) ligands: preparation, crystal structure and characterization

Two new Co^II coordination polymers (CPs), namely, catena-poly[[[(5-amino-2,4,6-tribromobenzene-1,3-dicarboxylato-κO)aquacobalt(II)]-bis[μ-1,3-bis(imidazol-1-ylmethyl)benzene-κ²N:N']] 4.75-hydrate], {[Co(C₈H₂Br₃NO₄)(C₁₄H₁₄N₄)₂(H₂O)]·4.75H₂O}_n, (1), and poly[(μ-5-amino-2,4,6-tribromobenzene-1,3-dicarboxylato-κ²O¹:O³)[μ-1,2-bis(imidazol-1-ylmethyl)benzene-κ²N:N']cobalt(II)], [Co(C₈H₂Br₃NO₄)(C₁₄H₁₄N₄)]_n, (2), have been synthesized successfully by the assembly of multifunctional 5-amino-2,4,6-tribromoisophthalic acid (H₂ATBIP) and Co^II ions in the presence of the flexible isomeric bis(imidazole) ligands 1,3-bis(imidazol-1-ylmethyl)benzene (mbix) and 1,2-bis(imidazol-1-ylmethyl)benzene (obix). The isomeric mbix and obix ligands have a big influence on the structures of CPs (1) and (2). CP (1) is composed of chains of nanometre-sized elliptical rings, in which the Co^II atom exhibits a distorted octahedral coordination geometry and ATBIP^2- acts as a monodentate ligand. Two adjacent chains are interlinked by π-π stacking interactions and hydrogen bonds, resulting in a supramolecular double chain. Hydrogen-bonded R₈⁶(16) rings extend adjacent supramolecular double chains into a two-dimensional supramolecular layer. Halogen bonding and a hydrogen-bonded R₄²(8) ring further link the two-dimensional supramolecular layers, leading to the formation of a three-dimensional supramolecular network. The Co^II ion in CP (2) is tetracoordinated, exhibiting a distorted tetrahedral configuration. The ATBIP^2- ligand exhibits a bis(monodentate) coordination bridging mode, linking adjacent Co^II ions into zigzag chains, which are further bridged by the auxiliary bridging obix ligand, resulting in a two-dimensional (4,4) topological network. Interlayer hydrogen and halogen-halogen bonding further extend the two-dimensional layers into a three-dimensional supramolecular network. A detailed analysis of the solid-state UV-Vis-NIR diffuse-reflectance spectra of (1) and (2) indicates that a wide optical band gap exists in both (1) and (2). CP (1) exhibits an irreversible dehydration-rehydration behaviour.

Crystal structure of catena-poly[[di-iodidomer-cury(II)]-μ-2,2'-di-thio-bis-(pyridine N-oxide)-κ2O:O']

The title compound, [HgI2(C10H8N2O2S2)] n , a one-dimensional coordination polymer with HgI2 units and 2,2'-di-thio-bis-(pyridine N-oxide) spacer ligands in an alternating fashion, forms helical chains running along the b axis in the crystal. Within a single coordination polymer strand, the axially chiral 2,2'-di-thio-bis-(pyridine N-oxide) ligands are homochiral, but the enanti-omeric conformation is present in adjacent strands. Within a coordination polymer strand, the iodido ligands point towards the centroids of the aromatic rings of the pyridine N-oxide moieties in the coordination sphere of HgII. Moreover, intra-strand C-H⋯O and C-H⋯I inter-actions, and inter-strand short S⋯I and S⋯O contacts are observed.

Effect of pH on the charge-assisted hydrogen-bonded assembly of the anionic [Cu(oxalate)2]2- building unit and N,N'-ditopic cations

By the solvothermal reaction under acidic conditions of Cu(NO₃)₂·3H₂O, Na₂C₂O₄ and the N,N'-ditopic organic coligands 1-(pyridin-4-yl)piperazine (ppz) and 1,2-bis(pyridin-4-yl)ethane (bpa), two novel anionic copper(II) coordination compounds were obtained, namely the one-dimensional coordination polymer catena-poly[4-(pyridin-1-ium-4-yl)piperazin-1-ium [[(oxalato-κ²O¹,O²)copper(II)]-μ-oxalato-κ³O¹,O²:O^1']], {(C₉H₁₅N₃)[Cu(C₂O₄)₂)]}_n or {(H₂ppz)[Cu(C₂O₄)₂]}_n, (I), and the discrete ionic complex 4,4'-(ethane-1,2-diyl)dipyridinium bis(oxalato-κ²O¹,O²)copper(II), (C₁₂H₁₄N₂)[Cu(C₂O₄)₂] or (H₂bpa)[Cu(C₂O₄)₂], (II). The products were characterized by single-crystal X-ray diffraction, elemental analysis, powder X-ray diffraction, thermogravimetric analyses and UV and IR spectroscopic techniques. The [Cu(C₂O₄)₂]^2- units for (I) and (II) are stabilized by H₂ppz²⁺ and H₂bpa²⁺ cations, respectively, via charge-assisted hydrogen bonds. Also, a study of the pH-controlled synthesis of this system shows that (I) was obtained at pH values of 2-4. When using bpa, a two-dimensional square-grid network of [Cu(C₂O₄)(bpa)]_n was obtained at a pH of 4. This indicates that the pH of the reaction also plays a key role in the structural assembly and coordination abilities of oxalate and N,N'-ditopic coligands.

Structure and electrical properties of a one-dimensional polymeric silver thiosaccharinate complex with argentophilic interactions

Among the potential applications of coordination polymers, electrical conductivity ranks high in technological interest. We report the synthesis, crystal structure and spectroscopic analysis of an Ag^I-thiosaccharinate one-dimensional coordination polymer {systematic name: catena-poly[[[aquatetrakis(μ₃-1,1-dioxo-1,2-benzisothiazole-3-thiolato-κ³N:S³:S³)tetrasilver(I)]-μ₂-4,4'-(propane-1,3-diyl)dipyridine-κ²N:N'] dimethyl sulfoxide hemisolvate]}, {[Ag₄(C₇H₄NO₂S₂)₄(C₁₃H₁₄N₂)(H₂O)]·0.5C₂H₆OS}_n, with the 4,4'-(propane-1,3-diyl)dipyridine ligand acting as a spacer. A relevant feature of the structure is the presence of an unusually short Ag...Ag distance of 2.8306 (9) Å, well within the range of argentophilic interactions, confirmed experimentally as such by a Raman study on the low-frequency spectrum, and corroborated theoretically by an Atoms in Molecules (AIM) analysis of the calculated electron density. Electrical conductivity measurements show that this complex can act as a semiconductor with moderate conductivity.

A new copper(II) coordination polymer containing chains of interconnected paddle-wheel antiferromagnetic clusters

The construction of supramolecular architectures based on inorganic-organic coordination frameworks with weak noncovalent interactions has implications for the rational design of functional materials. A new crystalline binuclear copper(II) one-dimensional polymeric chain, namely catena-poly[[[tetrakis(μ-4-azaniumylbutanoato-κ²O:O')dicopper(II)(Cu-Cu)]-μ-chlorido-[diaquadichloridocopper(II)]-μ-chlorido] bis(perchlorate)], {[Cu₃Cl₄(C₄H₉NO₂)₄(H₂O)₂](ClO₄)₂}_n, was obtained by the reaction of 4-aminobutyric acid (GABA) with CuCl₂·2H₂O in aqueous solution. The structure was established by single-crystal X-ray diffraction and was also characterized by IR spectroscopy and magnetic measurements. The crystal structure consists of [{Cu₂(GABA)₄}{CuCl₄(H₂O)₂}]⁺ cations and isolated perchlorate anions. Two symmetry-related Cu^II centres are bridged via carboxylate O atoms into a classical paddle-wheel configuration, with a Cu...Cu distance of 2.643 (1) Å, while bridging Cl atoms complete the square-pyramidal geometry of the metal atoms. The Cl atoms connect the paddlewheel moieties to a second Cu^II atom lying on an octahedral site, resulting in infinite helical chains along the c axis. The packing motif exhibits channels containing free perchlorate anions. The crystal structure is stabilized by hydrogen bonds between the perchlorate anions, the coordinated water molecules and the ammonium groups of the polymeric chains. The magnetic analysis of the title compound indicates a nontrivial antiferromagnetic behaviour arising from alternating weak-strong antiferromagnetic coupling between neighbouring Cu^II centres.

Complexes of nickel(II) and copper(II) with 1,2,4-triazole-3-carboxylic acid and of cobalt(III) with 3-amino-1,2,4-triazole-5-carboxylic acid

Because of their versatile coordination modes and strong coordination ability for metals, triazole ligands can provide a wide range of possibilities for the construction of metal-organic frameworks. Three transition-metal complexes, namely bis(μ-1,2,4-triazol-4-ide-3-carboxylato)-κ³N²,O:N¹;κ³N¹:N²,O-bis[triamminenickel(II)] tetrahydrate, [Ni₂(C₃HN₃O₂)₂(NH₃)₆]·4H₂O, (I), catena-poly[[[diamminediaquacopper(II)]-μ-1,2,4-triazol-4-ide-3-carboxylato-κ³N¹:N⁴,O-[diamminecopper(II)]-μ-1,2,4-triazol-4-ide-3-carboxylato-κ³N⁴,O:N¹] dihydrate], {[Cu₂(C₃HN₃O₂)₂(NH₃)₄(H₂O)₂]·2H₂O}_n, (II), (μ-5-amino-1,2,4-triazol-1-ide-3-carboxylato-κ²N¹:N²)di-μ-hydroxido-κ⁴O:O-bis[triamminecobalt(III)] nitrate hydroxide trihydrate, [Co₂(C₃H₂N₄O₂)(OH)₂(NH₃)₆](NO₃)(OH)·3H₂O, (III), with different structural forms have been prepared by the reaction of transition metal salts, i.e. NiCl₂, CuCl₂ and Co(NO₃)₂, with 1,2,4-triazole-3-carboxylic acid or 3-amino-1,2,4-triazole-5-carboxylic acid hemihydrate in aqueous ammonia at room temperature. Compound (I) is a dinuclear complex. Extensive O-H...O, O-H...N and N-H...O hydrogen bonds and π-π stacking interactions between the centroids of the triazole rings contribute to the formation of the three-dimensional supramolecular structure. Compound (II) exhibits a one-dimensional chain structure, with O-H...O hydrogen bonds and weak O-H...N, N-H...O and C-H...O hydrogen bonds linking anions and lattice water molecules into the three-dimensional supramolecular structure. Compared with compound (I), compound (III) is a structurally different dinuclear complex. Extensive N-H...O, N-H...N, O-H...N and O-H...O hydrogen bonding occurs in the structure, leading to the formation of the three-dimensional supramolecular structure.

Construction and photocatalytic properties of two metal-mediated coordination polymers based on benzene-1,3,5-tricarboxylic acid and trans-1-(pyridin-3-yl)-2-(pyridin-4-yl)ethene

With the rapid development of modern industry, water pollution has become an intractable environmental issue facing humans worldwide. In particular, the organic dyes discharged into natural water from dyestuffs, dyeing and the textile industry are the main sources of pollution in wastewater. To eliminate these types of pollutants, degradation of organic contaminants through a photocatalytic technique is an effective methodology. To exploit more crystalline photocatalysts for the degradation of organic dyes, two coordination polymers, namely catena-poly[[(3,5-dicarboxybenzene-1-carboxylato-κO¹)silver(I)]-μ-trans-1-(pyridin-3-yl)-2-(pyridin-4-yl)ethene-κ²N:N'], [Ag(C₉H₅O₆)(C₁₂H₁₀N₂)]_n or [Ag(H₂BTC)(3,4'-bpe)]_n, (I), and poly[[(μ₃-5-carboxybenzene-1,3-dicarboxylato-κ⁴O¹,O^1':O³:O³)[μ-trans-1-(pyridin-3-yl)-2-(pyridin-4-yl)ethene-κ²N:N']cadmium(II)] monohydrate], {[Cd(C₉H₄O₆)(C₁₂H₁₀N₂)]·H₂O}_n or {[Cd(HBTC)(3,4'-bpe)]·H₂O}_n, (II), have been prepared by the hydrothermal reactions of benzene-1,3,5-tricarboxylic acid (H₃BTC) and trans-1-(pyridin-3-yl)-2-(pyridin-4-yl)ethene (3,4'-bpe) in the presence of AgNO₃ or Cd(NO₃)₂·4H₂O, respectively. These two title compounds have been structurally characterized by IR spectroscopy, elemental analysis, single-crystal X-ray diffraction and powder X-ray diffraction. In (I), the Ag^I ions and organic ligands form a one-dimensional coordination chain, and adjacent coordination chains are connected by Ag...O interactions to give rise to a two-dimensional supramolecular network. Each two-dimensional network is entangled with other equivalent networks to generate an infrequent interlocked 2D→3D (2D and 3D are two- and three-dimensional, respectively) supramolecular framework. In (II), the Cd^II ions are bridged by the HBTC^2- and 3,4'-bpe ligands, which lie across centres of inversion, to give a two-dimensional coordination network. The thermal stabilities and photocatalytic properties of the title compounds have also been studied.

Syntheses, structures and characterization of isomorphous CoII and NiII coordination polymers based on 2-[(1H-imidazol-1-yl)methyl]-6-methyl-1H-benzimidazole and benzene-1,4-dicarboxylate

Careful choice of the organic ligands is one of the most important parameters in the rational design and synthesis of coordination polymers. Aromatic polycarboxylates have been widely used in the preparation of metal-organic polymers since they can utilize various coordination modes to form diverse structures and can act as hydrogen-bond acceptors and donors in the assembly of supramolecular structures. Nitrogen-heterocyclic organic compounds have also been used extensively as ligands for the construction of polymers with interesting structures. In the polymers catena-poly[[[diaquabis{2-[(1H-imidazol-1-yl)methyl]-6-methyl-1H-benzimidazole-κN³}cobalt(II)]-μ₂-benzene-1,4-dicarboxylato-κ²O¹:O⁴] dihydrate], {[Co(C₈H₄O₄)(C₁₂H₁₁N₄)₂(H₂O)₂]·2H₂O}_n, (I), and catena-poly[[[diaquabis{2-[(1H-imidazol-1-yl)methyl]-6-methyl-1H-benzimidazole-κN³}nickel(II)]-μ₂-benzene-1,4-dicarboxylato-κ²O¹:O⁴] dihydrate], {[Ni(C₈H₄O₄)(C₁₂H₁₁N₄)₂(H₂O)₂]·2H₂O}_n, (II), the Co^II or Ni^II ion lies on an inversion centre and exhibits a slightly distorted octahedral coordination geometry, coordinated by two N atoms from two imidazole rings and four O atoms from two monodentate carboxylate groups and two water molecules. The dicarboxylate ligands bridge metal ions forming a polymeric chain. The 2-[(1H-imidazol-1-yl)methyl]-6-methyl-1H-benzimidazole ligands coordinate to the Co^II or Ni^II centres in monodentate modes through an imidazole N atom and are pendant on opposite sides of the main chain. The two structures are isomorphous. In the crystal, the one-dimensional chains are further connected through O-H...O, O-H...N and N-H...O hydrogen bonds, leading to a three-dimensional supramolecular architecture. In addition, the IR spectroscopic properties, PXRD patterns, thermogravimetric behaviours and fluorescence properties of both polymers have been investigated.

A one-dimensional copper(II) coordination polymer incorporating succinate and N,N-diethylethylenediamine ligands: crystallographic analysis, vibrational and surface features, and DFT analysis

Transition metal atoms can be bridged by aliphatic dicarboxylate ligands to produce chains, layers and frameworks. The reaction of copper sulfate with succinic acid (H₂succ) and N,N-diethylethylenediamine (deed) in basic solution produces the complex catena-poly[[[(N,N-diethylethylenediamine-κ²N,N')copper(II)]-μ-succinato-κ²O¹:O⁴] tetrahydrate], {[Cu(C₄H₄O₄)(C₆H₁₆N₂)]·4H₂O}_n or {[Cu(succ)(deed)]·4H₂O}_n. Each carboxylate group of the succinate ligand coordinates to a Cu^II atom in a monodentate fashion, giving rise to a square-planar coordination environment. The succinate ligands bridge the Cu^II centres to form one-dimensional polymeric chains. Hydrogen bonds between the ligands and water molecules link these chains into sheets that lie in the ab plane. Density functional theory (DFT) calculations were used to support the experimental data. From these calculations, a good linear correlation was observed between the experimental and theoretically predicted structural and spectroscopic parameters (R² ∼ 0.97).

Synthesis, structural characterization and computational studies of catena-poly[chlorido[μ3-(pyridin-1-ium-3-yl)phosphonato-κ3O:O':O'']zinc(II)]

Coordination polymers are constructed from two basic components, namely metal ions, or metal-ion clusters, and bridging organic ligands. Their structures may also contain other auxiliary components, such as blocking ligands, counter-ions and nonbonding guest or template molecules. The choice or design of a suitable linker is essential. The new title zinc(II) coordination polymer, [Zn(C₅H₅NO₃P)Cl]_n, has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction and vibrational spectroscopy (FT-IR and FT-Raman). Additionally, computational methods have been applied to derive quantitative information about interactions present in the solid state. The compound crystallizes in the monoclinic space group C2/c. The four-coordinated Zn^II cation is in a distorted tetrahedral environment, formed by three phosphonate O atoms from three different (pyridin-1-ium-3-yl)phosphonate ligands and one chloride anion. The Zn^II ions are extended by phosphonate ligands to generate a ladder chain along the [001] direction. Adjacent ladders are held together via N-H...O hydrogen bonds and offset face-to-face π-π stacking interactions, forming a three-dimensional supramolecular network with channels. As calculated, the interaction energy between the neighbouring ladders is -115.2 kJ mol^-1. In turn, the cohesive energy evaluated per asymmetric unit-equivalent fragment of a polymeric chain in the crystal structure is -205.4 kJ mol^-1. This latter value reflects the numerous hydrogen bonds stabilizing the three-dimensional packing of the coordination chains.

Two cadmium(II) fluorous coordination compounds tuned by different bipyridines

Fluorine is the most electronegative element and can be used as an excellent hydrogen-bond acceptor. Fluorous coordination compounds exhibit several advantageous properties, such as enhanced high thermal and oxidative stability, low polarity, weak intermolecular interactions and a small surface tension compared to hydrocarbons. C-H...F-C interactions, although weak, play a significant role in regulating the arrangement of the organic molecules in the crystalline state and stabilizing the secondary structure. Two cadmium(II) fluorous coordination compounds formed from 2,2'-bipyridine, 4,4'-bipyridine and pentafluorobenzoate ligands, namely catena-poly[[aqua(2,2'-bipyridine-κ²N,N')(2,3,4,5,6-pentafluorobenzoato-κO)cadmium(II)]-μ-2,3,4,5,6-pentafluorobenzoato-κ²O:O'], [Cd(C₇F₅O₂)₂(C₁₀H₈N₂)(H₂O)]_n, (1), and catena-poly[[diaquabis(2,3,4,5,6-pentafluorobenzoato-κO)cadmium(II)]-μ-4,4'-bipyridine-κ²N:N'], [Cd(C₇F₅O₂)₂(C₁₀H₈N₂)(H₂O)₂]_n, (2), have been synthesized solvothermally and structurally characterized. Compound (1) shows a one-dimensional chain structure composed of Cd-O coordination bonds and is stabilized by π-π stacking and O-H...O hydrogen-bond interactions. Compound (2) displays a one-dimensional linear chain structure formed by Cd-N coordination interactions involving the 4,4'-bipyridine ligand. Adjacent one-dimensional chains are extended into two-dimensional sheets by O-H...O hydrogen bonds between the coordinated water molecules and adjacent carboxylate groups. Moreover, the chains are further linked by C-H...F-C interactions to afford a three-dimensional network. In both structures, hydrogen bonding involving the coordinated water molecules is a primary driving force in the formation of the supramolecular structures.

Structure of salts of lithium chloride and lithium hexafluorophosphate as solvates with pyridine and vinylpyridine and structural comparisons: (C5H5N)LiPF6, [p-(CH2=CH)C5H4N]LiPF6, [(C5H5N)LiCl]n, and [p-(CH2=CH)C5H4N]2Li(μ-Cl)2Li[p-(CH2=CH)C5H4N]2

Due to the flammability of liquid electrolytes used in lithium ion batteries, solid lithium ion conductors are of interest to reduce danger and increase safety. The two dominating general classes of electrolytes under exploration as alternatives are ceramic and polymer electrolytes. Our group has been exploring the preparation of molecular solvates of lithium salts as alternatives. Dissolution of LiCl or LiPF₆ in pyridine (py) or vinylpyridine (VnPy) and slow vapor diffusion with diethyl ether gives solvates of the lithium salts coordinated by pyridine ligands. For LiPF₆, the solvates formed in pyridine and vinylpyridine, namely tetrakis(pyridine-κN)lithium(I) hexafluorophosphate, [Li(C₅H₅N)₄]PF₆, and tetrakis(4-ethenylpyridine-κN)lithium(I) hexafluorophosphate, [Li(C₇H₇N)₄]PF₆, exhibit analogous structures involving tetracoordinated lithium ions with neighboring PF₆^- anions in the I-4 and Aea2 space groups, respectively. For LiCl solvates, two very different structures form. catena-Poly[[(pyridine-κN)lithium]-μ₃-chlorido], [LiCl(C₅H₅N)]_n, crystalizes in the P2₁2₁2₁ space group and contains channels of edge-fused LiCl rhombs templated by rows of π-stacked pyridine ligands, while the structure of the LiCl-VnPy solvate, namely di-μ-chlorido-bis[bis(4-ethenylpyridine-κN)lithium], [Li₂Cl₂(C₇H₇N)₄], is described in the P2₁/n space group as dinuclear (VnPy)₂Li(μ-Cl)₂Li(VnPy)₂ units packed with neighbors via a dense array of π-π interactions.

A new one-dimensional NiII coordination polymer with a two-dimensional supra-molecular architecture

The Ni^II cation is coordinated by three N atoms of three different 1,3,5-tris­(imidazol-1-ylmeth­yl)benzene ligands, one O atom of an ethane-1,2-diol mol­ecule, by a sulfate anion and a water mol­ecule, forming a distorted octa­hedral NiN₃O₃ coordination geometry. The tripodal 1,3,5-tris­(imidazol-1-ylmeth­yl)benzene ligands link the Ni^II cations to generate a metal–organic chain running along [100].

A new one-dimensional Ni^II coordination polymer of 1,3,5-tris­(imidazol-1-ylmeth­yl)benzene, namely catena-poly[[aqua­(sulfato-κO)hemi(μ-ethane-1,2-diol-κ²O:O′)[μ₃-1,3,5-tris­(1H-imidazol-1-ylmeth­yl)benzene-κ³N³,N^3′,N^3′′]nickel(II)] ethane-1,2-diol monosolvate monohydrate], {[Ni(SO₄)(C₁₈H₁₈N₆)(C₂H₆O₂)_0.5(H₂O)]·C₂H₆O₂·H₂O}_n, was synthesized and characterized by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction. The Ni^II cation is coordinated by three N atoms of three different 1,3,5-tris­(imidazol-1-ylmeth­yl)benzene ligands, one O atom of an ethane-1,2-diol mol­ecule, by a sulfate anion and a water mol­ecule, forming a distorted octa­hedral NiN₃O₃ coordination geometry. The tripodal 1,3,5-tris­(imidazol-1-ylmeth­yl)benzene ligands link the Ni^II cations, generating metal–organic chains running along the [100] direction. Adjacent chains are further connected by O—H⋯O hydrogen bonds, resulting in a two-dimensional supermolecular architecture running parallel to the (001) plane. Another water mol­ecule and a second ethane-1,2-diol mol­ecule are non-coordinating and are linked to the coordinating sulfate ions via O—H⋯O hydrogen bonds.

A new one-dimensional CuII complex with a three-dimensional supramolecular architecture incorporating benzene-1,3-dicarboxylate and 1-[(1H-benzotriazol-1-yl)methyl]-1H-imidazole

Subtle modifications of N-donor ligands can result in complexes with very different compositions and architectures. In the complex catena-poly[[bis{1-[(1H-benzotriazol-1-yl)methyl]-1H-imidazole-κN³}copper(II)]-μ-benzene-1,3-dicarboxylato-κ³O¹,O^1':O³], {[Cu(C₈H₄O₄)(C₁₀H₉N₅)₂(H₂O)]·2H₂O}_n, each Cu^II ion is six-coordinated by two N atoms from two crystallographically independent 1-[(1H-benzotriazol-1-yl)methyl]-1H-imidazole (bmi) ligands, by three O atoms from two symmetry-related benzene-1,3-dicarboxylate (bdic^2-) ligands and by one water molecule, leading to a distorted CuN₂O₄ octahedral coordination environment. The Cu^II ions are connected by bridging bdic^2- anions to generate a one-dimensional chain. The bmi ligands coordinate to the Cu^II ions in monodentate modes and are pendant on opposite sides of the main chain. In the crystal, the chains are linked by O-H...O and O-H...N hydrogen bonds, as well as by π-π interactions, into a three-dimensional network. A thermogravimetric analysis was carried out and the fluorescence behaviour of the complex was also investigated.

The coordination complex structures and hydrogen bonding in the three-dimensional alkaline earth metal salts (Mg, Ca, Sr and Ba) of (4-aminophenyl)arsonic acid

(4-Aminophenyl)arsonic acid (p-arsanilic acid) is used as an antihelminth in veterinary applications and was earlier used in the monosodium salt dihydrate form as the antisyphilitic drug atoxyl. Examples of complexes with this acid are rare. The structures of the alkaline earth metal (Mg, Ca, Sr and Ba) complexes with (4-aminophenyl)arsonic acid (p-arsanilic acid) have been determined, viz. hexaaquamagnesium bis[hydrogen (4-aminophenyl)arsonate] tetrahydrate, [Mg(H₂O)₆](C₆H₇AsNO₃)·4H₂O, (I), catena-poly[[[diaquacalcium]-bis[μ₂-hydrogen (4-aminophenyl)arsonato-κ²O:O']-[diaquacalcium]-bis[μ₂-hydrogen (4-aminophenyl)arsonato-κ²O:O]] dihydrate], {[Ca(C₆H₇AsNO₃)₂(H₂O)₂]·2H₂O}_n, (II), catena-poly[[triaquastrontium]-bis[μ₂-hydrogen (4-aminophenyl)arsonato-κ²O:O']], [Sr(C₆H₇AsNO₃)₂(H₂O)₃]_n, (III), and catena-poly[[triaquabarium]-bis[μ₂-hydrogen (4-aminophenyl)arsonato-κ²O:O']], [Ba(C₆H₇AsNO₃)₂(H₂O)₃]_n, (IV). In the structure of magnesium salt (I), the centrosymmetric octahedral [Mg(H₂O)₆]²⁺ cation, the two hydrogen p-arsanilate anions and the four water molecules of solvation form a three-dimensional network structure through inter-species O-H and N-H hydrogen-bonding interactions with water and arsonate O-atom and amine N-atom acceptors. In one-dimensional coordination polymer (II), the distorted octahedral CaO₆ coordination polyhedron comprises two trans-related water molecules and four arsonate O-atom donors from bridging hydrogen arsanilate ligands. One bridging extension is four-membered via a single O atom and the other is eight-membered via O:O'-bridging, both across inversion centres, giving a chain coordination polymer extending along the [100] direction. Extensive hydrogen-bonding involving O-H...O, O-H...N and N-H...O interactions gives an overall three-dimensional structure. The structures of the polymeric Sr and Ba complexes (III) and (IV), respectively, are isotypic and are based on irregular MO₇ coordination polyhedra about the M²⁺ centres, which lie on twofold rotation axes along with one of the coordinated water molecules. The coordination centres are linked through inversion-related arsonate O:O'-bridges, giving eight-membered ring motifs and forming coordination polymeric chains extending along the [100] direction. Inter-chain N-H...O and O-H...O hydrogen-bonding interactions extend the structures into three dimensions and the crystal packing includes π-π ring interactions [minimum ring centroid separations = 3.4666 (17) Å for (III) and 3.4855 (8) Å for (IV)].

Polymeric structure of a coproporphyrin I ruthenium(II) complex: a powder diffraction study

Porphyrin complexes of ruthenium are widely used as models for the heme protein system, for modelling naturally occurring iron-porphyrin systems and as catalysts in epoxidation reactions. The structural diversity of ruthenium complexes offers an opportunity to use them in the design of multifunctional supramolecular assemblies. Coproporphyrins and metallocoproporphyrins are used as sensors in bioassay and the potential use of derivatives as multiparametric sensors for oxygen and H⁺ is one of the main factors driving a growing interest in the synthesis of new porphyrin derivatives. In the coproporphyrin I Ru^II complex catena-poly[[carbonylruthenium(II)]-μ-2,7,12,17-tetrakis[2-(ethoxycarbonyl)ethyl]-3,8,13,18-tetramethylporphyrinato-κ⁵N,N',N'',N''':O], [Ru(C₄₄H₅₂N₄O₈)(CO)]_n, the Ru^II centre is coordinated by four N atoms in the basal plane, and by axial C (carbonyl ligand) and O (ethoxycarbonylethyl arm from a neighbouring complex) atoms. The complex adopts a distorted octahedral geometry. Self-assembly of the molecules during crystallization from a methylene chloride-ethanol (1:10 v/v) solution at room temperature gives one-dimensional polymeric chains.

A one-dimensional zinc(II) coordination polymer with a three-dimensional supramolecular architecture incorporating 1-[(1H-benzimidazol-2-yl)methyl]-1H-tetrazole and adipate

The synthesis of coordination polymers or metal-organic frameworks (MOFs) has attracted considerable interest owing to the interesting structures and potential applications of these compounds. It is still a challenge to predict the exact structures and compositions of the final products. A new one-dimensional coordination polymer, catena-poly[[[bis{1-[(1H-benzimidazol-2-yl)methyl]-1H-tetrazole-κN³}zinc(II)]-μ-hexane-1,6-dicarboxylato-κ⁴O¹,O^1':O⁶,O^6'] monohydrate], {[Zn(C₆H₈O₄)(C₉H₈N₆)₂]·H₂O}_n, has been synthesized by the reaction of Zn(Ac)₂ (Ac is acetate) with 1-[(1H-benzimidazol-2-yl)methyl]-1H-tetrazole (bimt) and adipic acid (H₂adi) at room temperature. In the polymer, each Zn^II ion exhibits an irregular octahedral ZnN₂O₄ coordination geometry and is coordinated by two N atoms from two symmetry-related bimt ligands and four O atoms from two symmetry-related dianionic adipate ligands. Zn^II ions are connected by adipate ligands into a one-dimensional chain which runs parallel to the c axis. The bimt ligands coordinate to the Zn^II ions in a monodentate mode on both sides of the main chain. In the crystal, the one-dimensional chains are further connected through N-H...O hydrogen bonds, leading to a three-dimensional supramolecular architecture. In addition, the title polymer exhibits fluorescence, with emissions at 334 and 350 nm in the solid state at room temperature.

A cadmium(II) coordination polymer formed from a third generation tetratopic tris(pyrazolyl)methane ligand

The reaction of a third generation tetratopic tris(pyrazolyl)methane ligand, namely 1,2,4,5-{[2,2,2-tris(1H-pyrazol-1-yl)ethoxy]methyl}benzene {1,2,4,5-C₆H₂[CH₂OCH₂C(pz)₃]₄, L4}, and [Cd₂(thf)₅](BF₄)₄ (thf is tetrahydrofuran) produces the coordination polymer catena-poly[[[bis[acetonitrilecadmium(II)]-μ₄-1,2,4,5-{[2,2,2-tris(1H-pyrazol-1-yl)ethoxy]methyl}benzene] tetrakis(tetrafluoroborate)]-diethyl ether-acetonitrile (1/2/2)], {[Cd₂(CH₃CN)₂(C₅₄H₅₄N₂₄O₄)](BF₄)₄·2C₄H₁₀O·2CH₃CN}_n. The Cd^II center is coordinated in a κ³-fashion by one tris(pyrazolyl)methane group and in a κ²-κ⁰ fashion by another, while the sixth coordination site on the Cd^II cation is occupied by an acetonitrile molecule. This bonding mode of the ligand generates an infinite one-dimensional structure built upon 32-atom metallomacrocycles connected by the C₆H₂ spacer. This compound is isostructural with the silver(I) analogue of this ligand, i.e. {[Ag₂(L4)](BF₄)₂·4CH₃CN}_n, thus showing the tendency of this system to form metal-based macrocyclic architectures.

A new one-dimensional cadmium(II) coordination polymer incorporating 4-[4-(1H-imidazol-1-yl)phenyl]pyridine and 5-hydroxybenzene-1,3-dicarboxylate ligands

The design and synthesis of new organic lgands is important to the rapid development of coordination polymers (CPs). However, CPs based on asymmetric ligands are still rare, mainly because such ligands are usually expensive and more difficult to synthesize. The new asymmetric ligand 4-[4-(1H-imidazol-1-yl)phenyl]pyridine (IPP) has been used to construct the title one-dimensional coordination polymer, catena-poly[[[aqua{4-[4-(1H-imidazol-1-yl-κN(3))phenyl]pyridine}cadmium(II)]-μ-5-hydroxybenzene-1,3-dicarboxylato-κ(3)O(1),O(1'):O(3)] monohydrate], {[Cd(C8H4O5)(C14H11N3)2(H2O)]·H2O}n, under hydrothermal reaction of IPP with Cd(II) in the presence of 5-hydroxyisophthalic acid (5-OH-H2bdc). The Cd(II) cation is coordinated by two N atoms from two distinct IPP ligands, three carboxylate O atoms from two different 5-OH-bdc(2-) dianionic ligands and one water O atom in a distorted octahedral geometry. The cationic [Cd(IPP)2](2+) nodes are linked by 5-OH-bdc(2-) ligands to generate a one-dimensional chain. These chains are extended into a two-dimensional layer structure via O-H...O and O-H...N hydrogen bonds and π-π interactions.

Supramolecular architectures in Co(II) and Cu(II) complexes with thiophene-2-carboxylate and 2-amino-4,6-dimethoxypyrimidine ligands

The coordination chemistry of mixed-ligand complexes continues to be an active area of research since these compounds have a wide range of applications. Many coordination polymers and metal-organic framworks are emerging as novel functional materials. Aminopyrimidine and its derivatives are flexible ligands with versatile binding and coordination modes which have been proven to be useful in the construction of organic-inorganic hybrid materials and coordination polymers. Thiophenecarboxylic acid, its derivatives and their complexes exhibit pharmacological properties. Cobalt(II) and copper(II) complexes of thiophenecarboxylate have many biological applications, for example, as antifungal and antitumor agents. Two new cobalt(II) and copper(II) complexes incorporating thiophene-2-carboxylate (2-TPC) and 2-amino-4,6-dimethoxypyrimidine (OMP) ligands have been synthesized and characterized by X-ray diffraction studies, namely (2-amino-4,6-dimethoxypyrimidine-κN)aquachlorido(thiophene-2-carboxylato-κO)cobalt(II) monohydrate, [Co(C5H3O2S)Cl(C6H9N3O2)(H2O)]·H2O, (I), and catena-poly[copper(II)-tetrakis(μ-thiophene-2-carboxylato-κ(2)O:O')-copper(II)-(μ-2-amino-4,6-dimethoxypyrimidine-κ(2)N(1):N(3))], [Cu2(C5H3O2S)4(C6H9N3O2)]n, (II). In (I), the Co(II) ion has a distorted tetrahedral coordination environment involving one O atom from a monodentate 2-TPC ligand, one N atom from an OMP ligand, one chloride ligand and one O atom of a water molecule. An additional water molecule is present in the asymmetric unit. The amino group of the coordinated OMP molecule and the coordinated carboxylate O atom of the 2-TPC ligand form an interligand N-H...O hydrogen bond, generating an S(6) ring motif. The pyrimidine molecules also form a base pair [R2(2)(8) motif] via a pair of N-H...N hydrogen bonds. These interactions, together with O-H...O and O-H...Cl hydrogen bonds and π-π stacking interactions, generate a three-dimensional supramolecular architecture. The one-dimensional coordination polymer (II) contains the classical paddle-wheel [Cu2(CH3COO)4(H2O)2] unit, where each carboxylate group of four 2-TPC ligands bridges two square-pyramidally coordinated Cu(II) ions and the apically coordinated OMP ligands bridge the dinuclear copper units. Each dinuclear copper unit has a crystallographic inversion centre, whereas the bridging OMP ligand has crystallographic twofold symmetry. The one-dimensional polymeric chains self-assemble via N-H...O, π-π and C-H...π interactions, generating a three-dimensional supramolecular architecture.

Orientational disorder in the one-dimensional coordination polymer catena-poly[[bis-(acetyl-acetonato-κ(2) O,O')cobalt(II)]-μ-1,4-di-aza-bicyclo-[2.2.2]octane-κ(2) N (1):N (4)]

The one-dimensional coordination polymer, self-assembled from bis­(acetyl­acetonato)cobalt(II) units as metal–complex connectors and 1,4-di­aza­bicyclo­[2.2.2]octane (DABCO) as linkers, can serve for a comparative investigation of the magnetic behaviour of analogous compounds. Space filling more symmetric than atom positions leads to pronounced orientational disorder for the DABCO ligand.

The title compound, [Co(C₅H₇O₂)₂(C₆H₁₂N₂)]_n, was obtained as a one-dimensional coordination polymer from bis­(acetyl­acetonato)di­aqua­cobalt(II), [Co(acac)₂(OH₂)₂], and 1,4-di­aza­bicyclo­[2.2.2]octane (DABCO), a di­amine with good bridging ability and rod-like spacer function. In the chain complex that extends along the c axis, the Co^II atom is six-coordinated, the O-donor atoms of the chelating acac ligands occupying the equatorial positions and the bridging DABCO ligands being in trans-axial positions. In the crystal structure, the DABCO ligand is conformationally disordered in a 50:50 manner as a result of its location across a crystallographic mirror plane. The metal–metal distance is very close to that in a related compound exhibiting weak anti­ferromagnetic exchange between the Co^II ions, and the title compound can thus be useful for obtaining more information about the contribution of different bridges to the magnetic coupling between paramagnetic ions.

The new one-dimensional coordination polymer catena-poly[[diaquasodium(I)]-μ-oxalato-[diaquairon(III)]-μ-oxalato]

The oxalate dianion is one of the most studied ligands and is capable of bridging two or more metal centres and creating inorganic polymers based on the assembly of metal polyhedra with a wide variety of one-, two- or three-dimensional extended structures. Yellow single crystals of a new mixed-metal oxalate, namely catena-poly[[diaquasodium(I)]-μ-oxalato-κ(4)O(1),O(2):O(1'),O(2')-[diaquairon(III)]-μ-oxalato-κ(4)O(1),O(2):O(1'),O(2')], [NaFe(C2O4)2(H2O)4]n, have been synthesized and the crystal structure elucidated by X-ray diffraction analysis. The compound crystallizes in the noncentrosymmetric space group I41 (Z = 4). The asymmetric unit contains one Na(I) and one Fe(III) atom lying on a fourfold symmetry axis, one μ2-bridging oxalate ligand and two aqua ligands. Each metal atom is surrounded by two chelating oxalate ligands and two equivalent water molecules. The structure consists of infinite one-dimensional chains of alternating FeO4(H2OW1)2 and NaO4(H2OW2)2 octahedra, bridged by oxalate ligands, parallel to the [100] and [010] directions, respectively. Because of the cis configuration and the μ2-coordination mode of the oxalate ligands, the chains run in a zigzag manner. This arrangement facilitates the formation of hydrogen bonds between neighbouring chains involving the H2O and oxalate ligands, leading to a two-dimensional framework. The structure of this new one-dimensional coordination polymer is shown to be unique among the A(I)M(III)(C2O4)2(H2O)n series. In addition, the absorption bands in the IR and UV-Visible regions and their assignments are in good agreement with the local symmetry of the oxalate ligand and the irregular environment of iron(III). The final product of the thermal decomposition of this precursor is the well-known ternary oxide NaFeO2.

Two-dimensional Zn(II) and one-dimensional Co(II) 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-κ(4)O:O':O'':O''')(pyridine-κN)zinc(II)], [Zn(C8H4O2)(C5H5N)]n, (I), and catena-poly[aqua(μ3-benzene-1,4-dicarboxylato-κ(3)O: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 BDC(2-) 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 BDC(2-) 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 BDC(2-) ligands and are octahedrally coordinated by three carboxylate O atoms from three BDC(2-) 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.

Synthesis, structural characterization and thermal properties of a new copper(II) one-dimensional coordination polymer based on bridging N,N'-bis(2-hydroxybenzylidene)-2,2-dimethylpropane-1,3-diamine and dicyanamide ligands

The design and synthesis of polymeric coordination compounds of 3d transition metals are of great interest in the search for functional materials. The coordination chemistry of the copper(II) ion is of interest currently due to potential applications in the areas of molecular biology and magnetochemistry. A novel coordination polymer of Cu(II) with bridging N,N'-bis(2-hydroxyphenyl)-2,2-dimethylpropane-1,3-diamine (H2L-DM) and dicyanamide (dca) ligands, catena-poly[[[μ2-2,2-dimethyl-N,N'-bis(2-oxidobenzylidene)propane-1,3-diamine-1:2κ(6)O,N,N',O':O,O']dicopper(II)]-di-μ-dicyanamido-1:2'κ(2)N(1):N(5);2:1'κ(2)N(1):N(5)], [Cu2(C19H20N2O2)(C2N3)2]n, has been synthesized and characterized by CHN elemental analysis, IR spectroscopy, thermal analysis and X-ray single-crystal diffraction analysis. Structural studies show that the Cu(II) centres in the dimeric asymmetric unit adopt distorted square-pyramidal geometries, as confirmed by the Addison parameter (τ) values. The chelating characteristics of the L-DM(2-) ligand results in the formation of a Cu(II) dimer with a double phenolate bridge in the asymmetric unit. In the crystal, the dimeric units are further linked to adjacent dimeric units through μ1,5-dca bridges to produce one-dimensional polymeric chains.

A threefold interpenetrated two-dimensional zinc(II) supramolecular architecture based on 3-nitrobenzoic acid and 4,4'-bipyridine

With regard to crystal engineering, building block or modular assembly methodologies have shown great success in the design and construction of metal-organic coordination polymers. The critical factor for the construction of coordination polymers is the rational choice of the organic building blocks and the metal centre. The reaction of Zn(OAc)2·2H2O (OAc is acetate) with 3-nitrobenzoic acid (HNBA) and 4,4'-bipyridine (4,4'-bipy) under hydrothermal conditions produced a two-dimensional zinc(II) supramolecular architecture, catena-poly[[bis(3-nitrobenzoato-κ(2)O,O')zinc(II)]-μ-4,4'-bipyridine-κ(2)N:N'], [Zn(C7H4NO4)2(C10H8N2)]n or [Zn(NBA)2(4,4'-bipy)]n, which was characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis and single-crystal X-ray diffraction analysis. The Zn(II) ions are connected by the 4,4'-bipy ligands to form a one-dimensional zigzag chain and the chains are decorated with anionic NBA ligands which interact further through aromatic π-π stacking interactions, expanding the structure into a threefold interpenetrated two-dimensional supramolecular architecture. The solid-state fluorescence analysis indicates a slight blue shift compared with pure 4,4'-bipyridine and HNBA.

Novel one- and two-dimensional Zn(II) coordination polymers based on a versatile 3,6-bis(pyridin-4-yl)phenanthrene-9,10-dione ligand

Two new Zn(II) coordination polymers, namely, catena-poly[[dibromidozinc(II)]-μ-[3,6-bis(pyridin-4-yl)phenanthrene-9,10-dione-κ(2)N:N']], [ZnBr2(C24H14N2O2)]n, (1), and poly[[bromido[μ3-10-hydroxy-3,6-bis(pyridin-4-yl)phenanthren-9-olato-κ(3)N:N':O(9)]zinc(II)] hemihydrate], {[ZnBr(C24H15N2O2)]·0.5H2O}n, (2), have been synthesized through hydrothermal reaction of ZnBr2 and a 60° angular phenanthrenedione-based linker, i.e. 3,6-bis(pyridin-4-yl)phenanthrene-9,10-dione, in different solvent systems. Single-crystal analysis reveals that polymer (1) features one-dimensional zigzag chains connected by weak C-H...π and π-π interactions to form a two-dimensional network. The two-dimensional networks are further stacked in an ABAB fashion along the a axis through C-H...O hydrogen bonds. Layers A and B comprise left- and right-handed helical chains, respectively. Coordination polymer (2) displays a wave-like two-dimensional layered structure with helical chains. In this compound, there are two opposite helical -Zn-HL- chains [HL is 10-hydroxy-3,6-bis(pyridin-4-yl)phenanthren-9-olate] in adjacent layers. The layers are packed in an ABAB sequence and are further connected through O-H...Br and O-H...O hydrogen-bond interactions to form a three-dimensional framework. In (1) and (2), the mutidentate L and HL ligands exhibits different coordination modes.

A new one-dimensional coordination polymer of 5-(1,3-dioxo-4,5,6,7-tetraphenylisoindolin-2-yl)isophthalic acid with manganese

The coordination polymer catena-poly[[(dimethylformamide-κO)[μ3-5-(1,3-dioxo-4,5,6,7-tetraphenylisoindolin-2-yl)isophthalato-κ(4)O(1),O(1'):O(3):O(3')](methanol-κO)manganese(III)] dimethylformamide monosolvate], {[Mn(C40H23NO6)(CH3OH)(C3H7NO)]·C3H7NO}n, has been synthesized from the reaction of 5-(1,3-dioxo-4,5,6,7-tetraphenylisoindolin-2-yl)isophthalic acid and manganese(II) acetate tetrahydrate in a glass tube at room temperature by solvent diffusion. The Mn(II) centre is hexacoordinated by two O atoms from one chelating carboxylate group, by two O atoms from two monodentate carboxylate groups and by one O atom each from a methanol and a dimethylformamide (DMF) ligand. The single-crystal structure crystallizes in the triclinic space group P\overline{1}. Moreover, the coordination polymer shows one-dimensional 2-connected {0} uninodal chain networks, and free DMF molecules are connected to the chains by O-H···O hydrogen bonds. The thermogravimetric and photoluminescent properties of the compound have also been investigated.

A new linear bismuth coordination polymer based on 1,10-phenanthroline-2,9-dicarboxylic acid: ionothermal synthesis, crystal structure and fluorescence properties

A new linear bismuth(III) coordination polymer, catena-poly[[chloridobismuth(III)]-μ3-1,10-phenanthroline-2,9-dicarboxylato-κ(6)O(2):O(2),N(1),N(10),O(9):O(9)], [Bi(C14H6N2O4)Cl]n, has been obtained by an ionothermal method and characterized by elemental analysis, energy-dispersive X-ray spectroscopy, IR spectroscopy, thermal stability studies and single-crystal X-ray diffraction. The structure is constructed by Bi(C14H6N2O4)Cl fragments in which each Bi(III) centre is seven-coordinated by one Cl atom, four O atoms and two N atoms. The coordination geometry of the Bi(III) cation is distorted pentagonal-bipyramidal (BiO4N2Cl), with one bridging carboxylate O atom and one Cl atom located in the axial positions. The Bi(C14H6N2O4)Cl fragments are further extended into a one-dimensional linear polymeric structure via subsequent but different centres of symmetry (bridging carboxylate O atoms). Neighbouring linear chains are assembled via weak C-H···O and C-H···Cl hydrogen bonds, forming a three-dimensional supramolecular architecture. Intermolecular π-π stacking interactions are observed, with centroid-to-centroid distances of 3.678 (4) Å, which further stabilize the structure. In addition, the solid-state fluorescence properties of the title coordination polymer were investigated.

Synthesis, structure and characterization of two copper(II) supramolecular coordination polymers based on a multifunctional ligand 2-amino-4-sulfobenzoic acid

Copper(II) coordination polymers have attracted considerable interest due to their catalytic, adsorption, luminescence and magnetic properties. The reactions of copper(II) with 2-amino-4-sulfobenzoic acid (H(2)asba) in the presence/absence of the auxiliary chelating ligand 1,10-phenanthroline (phen) under ambient conditions yielded two supramolecular coordination polymers, namely (3-amino-4-carboxybenzene-1-sulfonato-κO(1))bis(1,10-phenanthroline-κ(2)N,N')copper(II) 3-amino-4-carboxybenzene-1-sulfonate monohydrate, [Cu(C7H6N2O5S)(C12H8N2)2](C7H6N2O5S)·H2O, (1), and catena-poly[[diaquacopper(II)]-μ-3-amino-4-carboxylatobenzene-1-sulfonato-κ(2)O(4):O(4')], [Cu(C7H6N2O5S)(H2O)2]n, (2). The products were characterized by FT-IR spectroscopy, thermogravimetric analysis (TGA), solid-state UV-Vis spectroscopy and single-crystal X-ray diffraction analysis, as well as by variable-temperature powder X-ray diffraction analysis (VT-PXRD). Intermolecular π-π stacking interactions in (1) link the mononuclear copper(II) cation units into a supramolecular polymeric chain, which is further extended into a supramolecular double chain through interchain hydrogen bonds. Supramolecular double chains are then extended into a two-dimensional supramolecular double layer through hydrogen bonds between the lattice Hasba(-) anions, H2O molecules and double chains. Left- and right-handed 21 helices formed by the Hasba(-) anions are arranged alternately within the two-dimensional supramolecular double layers. Complex (2) exhibits a polymeric chain which is further extended into a three-dimensional supramolecular network through interchain hydrogen bonds. Complex (1) shows a reversible dehydration-rehydration behaviour, while complex (2) shows an irreversible dehydration-rehydration behaviour.

A one-dimensional CdII coordination polymer constructed from 4-(dimethylamino)pyridinium-1-acetate ligands and thiocyanate coordination bridges

A new cadmium-thiocyanate complex, namely catena-poly[1-carboxymethyl-4-(dimethylamino)pyridinium [cadmium(II)-tri-μ-thiocyanato-κ(4)N:S;κ(2)S:N] [[[4-(dimethylamino)pyridinium-1-acetate-κ(2)O,O']cadmium(II)]-di-μ-thiocyanato-κ(2)N:S;κ(2)S:N]], {(C9H13N2O2)[Cd(NCS)3][Cd(NCS)2(C9H12N2O2)]}n, was synthesized by the reaction of 4-(dimethylamino)pyridinium-1-acetate, cadmium nitrate tetrahydrate and potassium thiocyanide in aqueous solution. In the crystal structure, two types of Cd(II) atoms are observed in distorted octahedral coordination environments. One type of Cd(II) atom is coordinated by two O atoms from the carboxylate group of the 4-(dimethylamino)pyridinium-1-acetate ligand and by two N atoms and two S atoms from four different thiocyanate ligands, while the second type of Cd(II) atom is coordinated by three N atoms and three S atoms from six different thiocyanate ligands. Neighbouring Cd(II) atoms are linked by thiocyanate bridges to form a one-dimensional zigzag chain and a one-dimensional coordination polymer. Hydrogen-bond interactions are involved in the formation of the supramolecular network.

Crystal structure of catena-poly[[di-aqua-cobalt(II)]-bis-[μ-5-(4-carb-oxy-ylato-phenyl)picolinato]-κ(3) N,O (2):O (5);κ(3) O (5):N,O (2)-[di-aqua-cobalt(II)]-μ-1-[4-(1H-imidazol-1-yl)phen-yl]-1H-imidazole-κ(2) N (3):N (3')]

The asymmetric unit of the title polymeric Co^II complex, [Co₂(C₁₃H₇NO₄)₂(C₁₂H₁₀N₄)(H₂O)₄]_n, contains a Co^II cation, a 5-(4-carboxyl­atophen­yl)picolinate dianion, two coordination water mol­ecules and half of 1-[4-(1H-imidazol-1-yl)phen­yl]-1H-imidazole ligand. The Co^II cation is coordinated by two picolinate dianions, two water mol­ecules and one 1-[4-(1H-imidazol-1-yl)phen­yl]-1H-imidazole mol­ecule in a distorted N₂O₄ octa­hedral coordination geometry. The two picolinate dianions are related by an inversion centre and link two Co^II cations, forming a binuclear unit, which is further bridged by the imidazole mol­ecules, located about an inversion centre, into the polymeric chain propagating along the [-1-11] direction. In the crystal, the three-dimensional supra­molecular architecture is constructed by O—H⋯O hydrogen bonds between the coordinating water mol­ecules and the non-coordinating carboxyl­ate O atoms of adjacent polymeric chains.

Crystal structure of catena-poly[[[tetra-aqua-zinc(II)]-μ-1,4-bis-[4-(1H-imidazol-1-yl)benzo-yl]piperazine] dinitrate monohydrate]

In the title polymeric complex, {[Zn(C₂₄H₂₂N₆O₂)(H₂O)₄](NO₃)₂·2H₂O}_n, the Zn^II cation, located about a twofold rotation axis, is coordinated by two imidazole groups and four water mol­ecules in a distorted N₂O₄ octa­hedral geometry; among the four coordinate water mol­ecules, two are located on the same twofold rotation axis. The 1,4-bis­[4-(1H-imidazol-1-yl)benzo­yl]piperazine] ligand is centro-symmetric, with the centroid of the piperazine ring located on an inversion center, and bridges the Zn^II cations, forming polymeric chains propagating along [201]. In the crystal, O—H⋯O and weak C—H⋯O hydrogen bonds link the polymeric chains, nitrate anions and solvent water mol­ecules into a three-dimensional supra­molecular architecture. A short O⋯O contact of 2.823 (13) Å is observed between neighboring nitrate anions.

A one-dimensional zinc(II) coordination polymer based on mixed multidentate N- and O-donor ligands

In the title coordination polymer, catena-poly[[bis[{1-[(1H-benzimidazol-2-yl-κN(3))methyl]-1H-tetrazole}zinc(II)]-bis(μ4-pentane-1,5-dioato-1:2:1':2'κ(4)O(1):O(1'):O(5):O(5'))] methanol disolvate], {[Zn(C5H6O4)(C9H8N6)]·CH3OH}n, each Zn(II) ion is five-coordinated by four O atoms from four glutarate ligands and by one N atom from a 1-[(1H-benzimidazol-2-yl)methyl]-1H-tetrazole (bimt) ligand, leading to a slightly distorted square-pyramidal coordination environment. Two Zn(II) ions are linked by four bridging glutarate carboxylate groups to generate a dinuclear [Zn2(CO2)4] paddle-wheel unit. The dinuclear units are further connected into a one-dimensional chain via the glutarate ligands. The bimt ligands coordinate to the Zn(II) ions in a monodentate mode and are pendant on both sides of the main chain. In the crystal, the chains are linked by O-H···O and N-H···O hydrogen bonds into a two-dimensional layered structure. Adjacent layers are further packed into a three-dimensional network through van der Waals forces. A thermogravimetric analysis was carried out and the photoluminescent behaviour of the polymer was investigated.