1D Coordination Polymer Research Articles

A 2D antiferromagnetic coordination polymer constructed by benzotriazole-5-carboxylic acid

A 2D coordination polymer (CP) has been synthesized by the hydrothermal reactions of H2btca and Cu2+ ions in the presence of pyridine, {[Cu(btca)(py)2]·H2O}n (1) (py = pyridine, H2btca = benzotriazole-5-carboxylic acid), which is further characterized by the combination of various methods including single-crystal X-ray diffraction, powder X-ray diffraction (PXRD), elemental analysis, infrared (IR) spectrum, and thermogravimetric (TG) analysis. Structural analyses demonstrate that the asymmetric skeleton of CP 1 consists of one five-coordinated Cu2+ ion with square pyramid geometry, one btca2- ligand, two py molecules, and one lattice water molecule. Adjacent Cu2+ ions are bridged by 1,3-site N atoms of btca2− ligands to present a 1D chain, and neighboring 1D chains interconnected each other to generate a 3-connected ‘fes’-type network, which could be further stacked to present a 3D supramolecular structure through hydrogen bonds and π···π stacking interactions. The magnetic interaction among Cu2+ ions has been employed a 1D chain model, and the results indicate that the presence of antiferromagnetic interactions among Cu2+ ions.

2D Cu(I)-I Coordination Polymer with Smart Optoelectronic Properties and Photocatalytic Activity as a Versatile Multifunctional Material.

This work presents two isostructural Cu(I)-I 2-fluoropyrazine (Fpyz) luminescent and semiconducting 2D coordination polymers (CPs). Hydrothermal synthesis allows the growth of P-1 space group single crystals, whereas solvent-free synthesis produces polycrystals. Via recrystallization in acetonitrile, P21 space group single crystals are obtained. Both show a reversible luminescent response to temperature and pressure. Structure determination by single-crystal X-ray diffraction at 200 and 100 K allows us to understand their response as a function of temperature. Applying hydrostatic/uniaxial pressure or grinding also generates significant variations in their emission. The high structural flexibility of the Cu(I)-I chain is significantly linked to the corresponding alterations in structure. Remarkably, pressure can increase the conductivity by up to 3 orders of magnitude. Variations in resistivity are consistent with changes in the band gap energy. The experimental results are in agreement with the DFT calculations. These properties may allow the use of these CPs as optical pressure or temperature sensors. In addition, their behavior as a heterogeneous photocatalyst of persistent organic dyes has also been investigated.

Double advantages of 2D coordination polymer of coumarinyl‐pyridyl Schiff base decorated Zn(II): The fabrication of Schottky device and Anti‐carcinogenic activity

A 2D coordination polymer, [Zn2(BDC)4(QPR)2(H2O)]n (Zn(II)‐CP) (BDC2− = 1,4‐benzenedicarboxylato; QPR = 7‐[(pyridin‐4‐ylmethylene)‐amino]‐chromen‐2‐one), is presumably the first reported on coumarinyl‐pyridyl framework with terephthalato linker. The optical band gap, 2.91 eV, is obtained from the Tauc's plot that insists to fabricate an optically stimulated semiconducting device, and the electrical conductivity exhibited (Λ) is 8.07 × 10−3 S m−1 (dark) and 9.26 × 10−3 S m−1 (light). The cytotoxicity in the selected human cancer cell lines like HeLa, MDA‐MB 231, and HepG2 cells in relative to the normal kidney epithelial (NKE) cell line has been examined, and its efficacy is observed highest in inhibiting proliferation of HeLa cells (IC50, 21.02) compared with other cancer cells (IC50: 42.22 [HepG2] and 46.37 [MDA‐MB 231]). Further, the Zn(II)‐CP possess intracellular reactive oxygen species (ROS) generation and caspase‐3/7 activation leading to G2/M cell cycle arrest and apoptotic cell death in HeLa cell line. This novel coumarinyl‐pyridyl ligand appended Zn(II)‐CP has been employed for the fabrication of semiconducting device, which is quite impressive in view of existing energy crisis civilization; in addition, the compound has excellent bio‐activity.

Advance Progress on Luminescent Sensing of Nitroaromatics by Crystalline Lanthanide-Organic Complexes.

Water environment pollution is becoming an increasingly serious issue due to industrial pollutants with the rapid development of modern industry. Among many pollutants, the toxic and explosive nitroaromatics are used extensively in the chemical industry, resulting in environmental pollution of soil and groundwater. Therefore, the detection of nitroaromatics is of great significance to environmental monitoring, citizen life and homeland security. Lanthanide-organic complexes with controllable structural features and excellent optical performance have been rationally designed and successfully prepared and used as lanthanide-based sensors for the detection of nitroaromatics. This review will focus on crystalline luminescent lanthanide-organic sensing materials with different dimensional structures, including the 0D discrete structure, 1D and 2D coordination polymers and the 3D framework. Large numbers of studies have shown that several nitroaromatics could be detected by crystalline lanthanide-organic-complex-based sensors, for instance, nitrobenzene (NB), nitrophenol (4-NP or 2-NP), trinitrophenol (TNP) and so on. The various fluorescence detection mechanisms were summarized and sorted out in the review, which might help researchers or readers to comprehensively understand the mechanism of the fluorescence detection of nitroaromatics and provide a theoretical basis for the rational design of new crystalline lanthanide-organic complex-based sensors.

Catalytic activation of persulfate by 3D Cd(II) coordination polymers based on a flexible cyclotriphosphazene-functionalized ligand

Dye removal in wastewater can be done by catalytic reaction with coordination polymers. Herein, Two 3D Cd(II) coordination polymers, namely, {[Cd3(L)(H2O)4].(H2O)(DMF)}n (GTU-1) and {[Cd3(L)(4,4-bpy))(H2O)2].(H2O)}n (GTU-2), were prepared with a novel hexapod-shaped molecular building block, hexakis(methyl-2-(4-phenoxyphenyl)acetatebenzene) cyclotriphosphazene (H6L), by solvothermal reactions in dimethylformamide with nitric acid as the modulator. Cd(II) coordination polymers were characterized by Fourier transform infrared spectroscopy, thermal analysis, scanning electron microscopy, powder X-ray diffraction analysis and single crystal X-ray diffraction technique. GTU-1 represents a 3D pillared-layered coordination polymer structure containing 2D Cd-carboxylate (Cd(COO)n)-based inorganic building unit (IBU) whereas GTU-2 is a 3D coordination polymer derived from 1D IBU bridged together by deprotonated L6- and judiciously chosen ancillary linker 4,4-bipyridine (4,4-bpy). In both complexes, the flexible multisite cyclotriphosphazene bridging ligand (H6L) is completely deprotonated. GTU-2 exhibited relatively good catalytic activity towards rhodamine B (RhB), Methylen Blue (MB) and Acid Red 17 (AR-17) removal in aqueous solution.

Structural characterization and photoelectrochemistry of coordination polymer of Pb(II)‐naphthyl‐isonicotinohydrazide Schiff base

An organic–inorganic hybrid Pb(II)‐based 1D coordination polymer, {[Pb(NSB)NO3.DMF]}n (CP) (H‐NSB = isonicotinic acid (2‐hydroxy‐naphthalen‐1‐ylmethylene)‐hydrazide; DMF = N,N‐dimethylformamide), is structurally characterized by single crystal X‐ray diffraction measurement and other spectroscopic data. The structure shows that the ligand, H‐NSB serves as a monoanionic tetradentate N2O2 chelating linker of μ3‐κN,κO;κO,N,O type, where κO (phenolato‐O) brings two Pb(II) centres together and the tridentate NO2 unit chelates (κO,N,O) with one Pb(II) unit followed by its pyridyl‐N links (κN) with nearest Pb(II) centre for propagating as a seven coordinated distorted pentagonal bi‐pyramidal PbO5N2 core (one O donor comes from DMF and another O from NO3−). Thus, 1D chain is constructed that is thermally stable. The noncovalent interactions (π…π, H‐bonding and C‐H…π) amongst the 1D chains make supramolecular 3D architecture. The Hirshfeld surface analysis approves the existence of several noncovalent interactions for the formation of 3D network. The reasonable band gap of 3.04 eV for the CP lies in the semiconducting region, which simulates fabrication of photoelectrochemical device with high magnitude of photocurrent (current density: ~2.5 μA cm−2). Mott–Schottky analysis indicates the n‐type semiconducting behaviour, and chronoamperometry plot also shows the stability of the material against photo corrosion. Present elucidation would decipher an encouraging pathway for harvesting next‐generation energy resources based on a novel Pb(II)‐naphthyl‐isonicotinohydrazide Schiff base‐based CP.

2.2]Paracyclophane Derivatives as Building Blocks for Coordination Polymers.

Several new di- and tetracarboxylic [2.2]paracyclophane derivatives were obtained via Suzuki coupling between the appropriately brominated [2.2]paracyclophanes and 4-(methoxycarbonyl)phenylboronic acid. The reaction of one of these products, namely pp-bis(4-carboxyphenyl)[2.2]paracylophane (12), with zinc nitrate afforded a 2D coordination polymer comprising zinc-carboxylate paddlewheel clusters linked together by cyclophane cores. The zinc center is five-coordinated in a square-pyramidal geometry, with a DMF oxygen atom at the apex and four carboxylate oxygen atoms in the base.

Organometallic-Organic Hybrid Assemblies Featuring the Diantimony Complex [Cp2Mo2(CO)4(μ,η2-Sb2)], Ag(I) Ions and Ndonor Molecules as Building Blocks.

The reactions of the of the organometallic ligand complex [Cp2Mo2(CO)4(μ,η2-Sb2)] (C) with Ag[TEF] ([TEF]‾ = [Al{OC(CF3)3}4]‾) in the presence of a number of di- or polytopic N-donor molecules (1,6,7,12-tetraazaperylene (L1), 2,2'-bipyrimidine (L2), 4,4'-bipyridine (L3), trans-1,2-di(4-pyridyl)ethylene (L4)) and 1,3-di(4-pyridyl)propane (L5), were studied. These reactions lead, depending on the reaction stoichiometry and choice of linker, to the selective formation of dimeric or tetrameric supramolecular coordination complexes as well as 1D and 2D coordination polymers (CPs). The presented compounds are unique examples of supramolecular complexes incorporating both organometallic Sb-donor and organic N-donor molecules as ligands to stabilize metal ions. Moreover, one of the formed compounds, the CP [Ag4(η2:1-C)4(L4)4]n[TEF]4n, represents an exceptional 1D polymer incorporating both N- and Sb-donor ligands as connectors for metal ions.

Study of the Degradation of Dyes by a Mononuclear Copper Complex Forming a Zigzag Chain

The titled mononuclear complex [Cu (L)] with the formally tetradentate schiff base ligand, [N,N’-bis (2-hydroxy-3-methoxybenzylidene)-1,3-diaminopropan-2-ol] has been synthesized and characterized using IR spectroscopy and elemental analysis. Crystal structure has been determined by XRD which reveals the pseudo octahedral complex geometry and the use of hydroxo bridges between two neighbor units to form a 1D coordination polymer. The use of this complex as a catalyst for the degradation of two textile dyes, in the presence of the appropriate amount of H2O2 and a UV light source has given very good results with yields exceeding 98% after 50 minutes.

Synthesis and microstructure of BaMnO3 oxide obtained from coordination precursor

We report here on a new coordination heterometallic [MnII–BaII] polymer with 2,3-pyridinedicarboxylic bridging ligand and its application as single-source for access to perovskite oxide BaMnO3. The structure and magnetic properties of both coordination compound and the obtained oxide have been investigated. The tridentate and pentadentate 2,3-pyridinedicarboxylic ligands bridge MnII and BaII heteroatoms forming a 3D coordination polymer. The XRD and EDX results confirm the formation of the hexagonal phase of pure BaMnO3 perovskite.The magnetic and EPR spectroscopy measurements of 2 show characteristic structural and magnetic transitions reported for 2H–BaMnO3.

Single crystal structure feature of a new 1D-coordination polymer of Mn (II); antioxidant activity and protective effects on BLC (both in enzyme activity and in structure)

A new polymer of Mn (II) formulated as [(NIH) (Cl) Mn1 (µ-NIH)2 Mn2(Cl)) (H2O)2] [(NIH) (H2O) Mn3 (µ-NIH)2Mn4(H2O)3]n.6Cl·4H2ONIH, where NIH = 4-Pyridinecarboxylic acid hydrazide = Isoniazid = Isonicotinic acid hydrazide has been synthesized and characterized by elemental analysis, Fourier-transform infrared spectroscopy) FT-IR (, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), Powder X-ray Diffraction(PXRD), and single crystal X-ray structure (SC-XRD). SC-XRD results revealed two 1D anionic coordination polymers which are accompanied by four water molecules, one isoniazid molecule, and six chlorine ions. Parallelepiped light orange crystals of Mn complex crystallize in a triclinic system with space group P1. Centers of Mn1, Mn2, Mn3, and Mn4 adopted slightly distorted octahedral. The antioxidant behavior of the Mn complex was tested through a DPPH assay and found that the Mn complex has a good performance in decolorizing the DPPH solution, so it reduces DPPH activity at a concentration of 50 mg L−1 to about 82%. Reactive oxygen species can cause oxidative stress in organisms. Catalase as a valuable antioxidant enzyme can play a protective role. Spectral techniques were used to investigate the effect of the Mn complex on the structure and function of bovine liver catalase (BLC). The catalytic activity of the BLC was significantly improved with the Mn complex. Fluorescence and CD results showed that this complex can induce the environmental changes of amino acid residues (especially Trp) and increase the stability of the secondary structure of the BLC by increasing the α-helix. The interaction process was spontaneous and exothermic, and the most important forces involved in it were van der Waals forces and hydrogen bonds.

Crystal Structures of 3,3′,5,5′-Tetrabromo-4,4′-bipyridine and Co(II) Coordination Polymer Based Thereon

The crystal structure of 3,3′,5,5′-tetrabromo-4,4′-bipyridine (BrBipy, 1) was determined, and the features of non-covalent interactions in solid state were investigated by theoretical methods. Using BrBipy as a linker ligand, 1D coordination polymer {[Co(BrBipy)(NO3)2(CH3OH)2]} (2) was obtained and characterized.

Tuning the Thermometric Features in 1D Luminescent EuIII and TbIII Coordination Polymers through Different Bridge Phosphine Oxide Ligands.

TbIII and EuIII systems have been investigated as ratiometric luminescent temperature probes in luminescent coordination polymers due to TbIII → EuIII energy transfer (ET). To help understand how ion-ion separation, chain conformation as well as excitation channel impact their thermometric properties, herein, [Eu(tfaa)3(μ-L)Tb(tfaa)3]n one-dimensional (1D) coordination polymers (tfaa- = trifluoroacetylacetonate, and L = [(diphenylphosphoryl)R](diphenyl)phosphine oxide, R = ethyl - dppeo - or butyl - dppbo) were synthesized. The short μ-dppeo bridge ligand leads to a more linear 1D polymeric chain, while the longer μ-dppbo bridge leads to tighter packed chains. As the temperature rises from 80 K, upon direct TbIII excitation at 488 nm, the TbIII emission intensity decreases, while the EuIII emission intensity increases after 160 and 200 K when L = dppeo or dppbo, respectively. The temperature-dependent emission intensities, due to TbIII → EuIII ET, enable the development of ratiometric luminescent temperature probes featuring maximum relative thermal sensitivity up to 3.8% K-1 (250 K, L = dppbo, excitation at 488 nm). On the other hand, the same system displays maximum thermal sensitivity up to 3.5% K-1 (323 K) upon ligand excitation at 300 nm. Thus, by changing the excitation channel and bridge ligand that leads to modification of the polymer conformations, the maximum relative thermal sensitivity can be tuned.

Complexes of NiII, CoII, ZnII, and CuII with Promising Anti-Tuberculosis Drug: Solid-State Structures and DFT Calculations

Four new NiII, CoII, ZnII, and CuII complexes with the promising anti-tuberculosis drug (E/Z)-N′-((5-Hydroxy-3,4-bis(hydroxymethyl)-6-methylpyridin-2-yl)methylene)-isonicotino-hydrazide (LH) were synthesized and characterized by structural methods: single-crystal X-ray diffraction, vibrational spectroscopy, and mass spectrometry. The NiII, CoII, and ZnII metal ions form only amorphous phases with various morphologies according to mass spectrometry and IR spectroscopy. The CuII forms a crystalline 1D coordination polymer with the relative formula {[CuLCl]·0.5H2O}∞1. Even though the LH ligand in the crystalline state includes a mixture of E-/Z-isomers, only the tautomeric iminol E-/Z-form is coordinated by CuII in the crystal. The copper(II) complex crystallizes in the monoclinic P21/n space group with the corresponding cell parameters a = 16.3539(11) Å, b = 12.2647(6) Å, and c = 17.4916(10) Å; α = 90°, β = 108.431(7)°, and γ = 90°. DFT calculations showed that the Z-isomer of the LH ligand in solution has the lowest formation energy due to intramolecular hydrogen bonds. According to the quantum chemical calculations, the coordination environment of the CuII atom during the transfer of the molecule into the solution remains the same as in the crystal, except for the polymeric bond, namely, distorted trigonal bipyramidal. Some of the complexes investigated can be used as effective sensors in biosystems.

3D ZnII-Based coordination polymer: Synthesis, structure and fluorescent sensing property for nitroaromatic compounds

A water-stable ZnII-based coordination polymer (CP) with excellent photophysical behavior, namely [Zn2L(atez)(H2O)2] (compound 1; H3L = 4-(2′,3′-dicarboxylphenoxy); atez = 5-aminotetrazole), was successfully prepared by the solvothermal reaction of Zn ions with a π-conjugated and semi-rigid multicarboxylate ligand H3L in the presence of N-containing linker atez. Compound 1 displays a hierarchically pillared three-dimensional (3D) (3,4,5)-connected (4·62) (42·64) (43·64·83) net which is based on two-dimensional (2D) multicarboxylate- ZnII layers strutted by the atez ligands. Sensing investigations of compound 1 reveal that this material can selectively and sensitively detect nitroaromatic compounds in water suspension through fluorescence quenching effect. In particular, it is worth noting that it shows highly specific detection of nitrobenzene (NB) and 2,4,6-trinitrophenol (TNP) with remarkable quenching constants (KSV = 7.5 × 104 M−1 for NB and KSV = 1.9 × 105 M−1 for TNP) and low limit of detection (LOD = 0.93 μM for NB and LOD = 0.36 μM for TNP). Investigations reveal that the probable mechanisms for such sensing processes are the concurrent presence of fluorescence resonance energy transfer (FRET) as well as photoinduced electron transfer (PET) between the CP and nitroaromatic molecules. This work not only offers an effective route to improve the application of fluorescent CPs but also provide one novel probable fluorescence probe for nitroaromatic compounds.

SCSC Transformation and Post-Synthesis Modification of MOFs with Proton Conduction and Ratiometric Fluorescence-Sensing Properties.

The modification of metal-organic framework (MOF) materials to facilitate their practical applications is an extremely challenging and meaningful topic. In this work, two stepwise modification strategies for MOFs were conducted. First, we have demonstrated a single-crystal-to-single-crystal (SCSC) transformation from a microporous three-dimensional (3D) MOF to a two-dimensional (2D) coordination polymer (CP). The centrosymmetric [Cd(3-bpdb)(MeO-ip)]n (1) transforms into a chiral [Cd2(3-bpdb)(MeO-ip)2(CH3OH)2]n (2), which is triggered by the reaction time with methanol that acts as a structure-directing agent. The conversion relationship of 1 to 2 at different reaction times was studied in detail. Density functional theory (DFT) calculations clearly state that the irreversible formation of 2 is thermodynamically favorable. Intriguingly, 2 exhibits good proton conduction of 1.34 × 10-3 S cm-1 under 363 K and 98% relative humidity (RH) due to unique H-bond network characteristics. To the best of our knowledge, there are very few cases of 3D to 2D SCSC transformation stimulated by reaction time. The results have important implications for understanding the SCSC transformation mechanism and synthetic chemistry. On the other hand, the lanthanide3+-functionalized hybrids (Ln3+-MOF), Ln3+@1, were continuously prepared by incorporating luminescent Ln3+ ions into the structure of 1 through encapsulating post-synthesis modification (PSM). Tb3+@1 exhibits double emission in water and shows visual ratiometric fluorescence behavior for sensing glutamic acid (Glu), tryptophan (Trp), and Al3+, which is more reliable and accurate than single emission. Our work may not only provide new insights into the multiple modification of MOF materials but also promote the practical application of such materials.

Macroscopic shaping of coordination polymer via crystal–glass phase transformation as monolithic catalyst for efficient catalyst recovery

To circumvent the difficult processability and recovery of catalytic materials in powder form, we herein report macroscopic shaping of 1D coordination polymer consisting of zinc ions, orthophosphate, and benzimidazole, namely ZnPBIm, motivated by the crystal–glass phase transformation. Glassy ZnPBIm monoliths with different shapes and sizes were prepared via a melt-quench process without using the secondary component. As a heterogeneous acid catalyst, the glassy ZnPBIm monoliths contribute to the esterification of levulinic acid with ethanol at 100 °C with recyclability for at least three consecutive cycles, and over 90% of catalyst mass was recovered. The macroscopic shape of the monoliths was retained after 24 h of reaction. Surface crystallization of glassy ZnPBIm was induced by the presence of water during esterification, and the glass domain serves as a macroscopic support for the crystallized domain.

Complex formation of 1D-coordination poly-mers based on arendiyl-bisphosphinic acid

Within the framework of the density functional theory and the ab initio pseudopotential, we have obtained the spatial distributions of the valence electrons density, the electron energy spectra and the atom charge states of 1D-coordination polymers based on arendiyl-bisphosphinic acids and metal ions. Formation of one-dimensional polymer chains takes place under participation of strong intermolecular bonds.

Synthesis, crystal structures and electrocatalytic properties of 2D and 3D Co(Ⅱ) Coordination polymers based on semi-rigid tricarboxylic acid ligand

The tricarboxylic ligand, 4′,4′,4′-[(trimethylamino)]-tris[(1,1′-biphenyl)-2-carboxylic acid] (H3TMCA), is designed and synthesized to self-assembly two novel cobalt coordination polymers, formulated as {[Co2(TMCA)(OH)(DMF)(H2O)]}n (1), {[Co3(TMCA)2]}n (2). Interesting, due to the flexibility of the H3TMCA, the final frameworks of 1-2 can change depending on the reaction of temperature and solvents. Complex 1 is a (3, 6)-connected of type kgd two-dimensional (2D) network with a point (Schlafli) symbol of {43}2{46. 66. 83}. Complex 2 is a (4, 6)-connected 2-nodal three-dimensional (3D) net with point (Schlafli) symbol of {415}2{42. 84}3. In addition, the electrocatalytic activity of these Co-CPs were studied in detail.

Cyclic [Cu-biRadical]2 Secondary Building Unit in 2p-3d and 2p-3d-4f Complexes: Crystal Structure and Magnetic Properties.

Employing the new nitronyl nitroxide biradical ligand biNIT-3Py-5-Ph (2-(5-phenyl-3-pyridyl)-bis(4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide)), a 16-spin Cu-radical complex, [Cu8(biNIT-3Py-5-Ph)4(hfac)16] 1, and three 2p-3d-4f chain complexes, {[Ln(hfac)3][Cu(hfac)2]2(biNIT-3Py-5-Ph)2}n (LnⅢ= Gd 2, Tb 3, Dy 4; hfac = hexafluoroacetylacetonate), have been prepared and characterized. X-ray crystallographic analysis revealed in all derivatives a common cyclic [Cu-biNIT]2 secondary building unit in which two bi-NIT-3Py-5-Ph biradical ligands and two CuII ions are associated via the pyridine N atoms and NO units. For complex 1, two such units assemble with four additional CuII ions to form a discrete complex involving 16 S = 1/2 spin centers. For complexes 2-4, the [Cu-biNIT]2 units are linked by LnIII ions via NO groups in a 1D coordination polymer. Magnetic studies show that the coordination of the aminoxyl groups with Cu or Ln ions results in behaviors combining ferromagnetic and antiferromagnetic interactions. No slow magnetic relaxation behavior was observed for Tb and Dy derivatives.