Zn Coordination Polymers Research Articles

A luminescent Zn(ii) coordination polymer based on a new tetrazolyl–benzimidazolyl tripodal heterotopic ligand for detecting acetone and triethylamine in water

A Zn(ii) CP based on a new heterotopic tripodal ligand was synthesized and its applications in luminescent sensing of acetone and TEA were studied.

Coordination polymer derived Fe-N-C electrocatalysts with high performance for the oxygen reduction reaction in Zn-air batteries.

Developing high performance noble-metal-free electrocatalysts as an alternative to Pt-based catalysts for the oxygen reduction reaction (ORR) in energy conversion devices is highly desirable. We report herein the preparation of a coordination-polymer (CP)-derived Fe/CP/C composite as an electrocatalyst for the ORR with excellent activity and stability both in solution and in Zn-air batteries. The Fe/CP/C catalyst was obtained from the pyrolysis of an iron porphyrin Fe(TPP)Cl (5,10,15,20-tetraphenyl-21H,23H-porphyrin iron(III) chloride) grafted Zn-coordination polymer with dangling functional groups 4,4'-oxybisbenzoic acid and 4,4'-bipyridine ligands. The Fe/CP/C catalyst showed much higher ORR activity with a half-wave potential (E1/2) of 0.90 V (vs. RHE) than the Fe/C catalyst (E1/2 = 0.85 V) derived from the carbon-black-supported Fe porphyrins in 0.1 M KOH solution. When Fe/CP/C was used as the cathode electrocatalyst in Zn-air batteries (ZABs), the ZABs achieved a significantly higher open circuit voltage (OCV = 1.43 V) and maximum power density (Pmax = 142.8 mW cm-2) compared with Fe/C (OCV = 1.38 V, Pmax = 104.5 mW cm-2) and commercial 20 wt% Pt/C (OCV = 1.41 V, Pmax = 117.6 mW cm-2). Using dangling functional groups in CP to increase the loading efficiency of iron porphyrins offered a facile method to prepare high-performance noble-metal-free electrocatalysts for the ORR, which may provide promising applications to energy conversion devices.

Zn-coordination polymers for fluorescence sensing various contaminants in water

Luminescent coordination polymers (LCPs) have garnered significant attention from researchers as promising materials for detecting contaminants. In this paper, three new LCPs ([Zn(tib)(opda)]n⋅H2O (1), [Zn3(tib)2(mpda)3]n⋅5H2O (2), [Zn (tib)(ppda)]n⋅H2O (3)) with different structures (LCP 1–3: 1D, 2D, 1D) using phenylenediacetic acid isomers and 1,3,5-tris (1-imidazolyl) benzene (tib) are synthesized. The specific surface areas (BET) of LCP 1–3 are 4 m2/g, 19 m2/g, and 13 m2/g respectively. LCP 1–3 exhibit excellent fluorescence properties and can serve as fluorescent probe for the detection of inorganic contaminants and organic contaminants. Due to the large BET of LCP 2, the detection limits for trace analytes surpass those of LCP 1 and 3. The detection limits of LCP 2 for Fe3+, nitrobenzene (NB), chloramphenicol (CAP), and pyrimethanil (PTH) are 8.3 nM, 0.016 μM, 0.19 μM, and 0.032 μM, respectively, and the fluorescence quenching rates are 98.6 %, 98.8 %, 92.3 %, and 98.8 %, respectively. These values outperform most reported in the literature. The quantum yields of LCP 1–3 are 11.84 %, 25.22 %, 22.00 % respectively. Real sample testing of LCP 1–3 reveals favorable performance, where spiked recoveries of LCP 2 for the detection of pyrimethanil in grape skins ranged from 99.62 % to 119.3 % with a relative standard deviation (RSD) of 0.627 % to 4.56 % (n = 3). The fluorescence quenching mechanism was attributed to a combination of photoelectron transfer (PET), resonance energy transfer (RET), and competitive absorption (CA). This study advances the application of LCPs in luminescence sensing and contributes to the expansion of novel materials for detecting environmental pollutants.

Zn(II) Coordination Polymer: Luminescence Sensing for Fe3+ Ion and Used as Metal Gel Particles Against Lung Cancer.

Presented here is a new Zn(II) coordination polymer, namely [Zn2(L)2(bpe)]n (1, H2L = 4-({2-[(4-carboxyphenoxy)methyl]phenyl}methoxy)benzoic acid, bpe = 1,2-bis(4-pyridinyl)ethane), which has been hydrothermally synthesized via the mixed-ligand strategy. Moreover, compound 1 emits intense luminescence at room temperature, and can be used as a luminescent sensor for the detection of Fe3+ in water solution with high selectivity and sensitivity. As representatives of natural polysaccharides, hyaluronic acid (HA) and carboxymethyl chitosan (CMCS) have good biocompatibility. A new type of HA/CMCS gel particles loaded with Paclitaxel drug metal-organic framework was prepared by chemical synthesis method and its micromorphology was studied. Finally, biological experiments were conducted to evaluate the new system's effect on the activity of human lung cancer cells.

A fluorescent sensor based on Zn(II)-coodination polymers bearing mixed ligands for the sensitive detection of riboflavine, imidacloprid and nitenpyram

Two new 2D Zn(II) coordination polymers (BAO28 and BAO29), formulated as [Zn(DIN)(HPT)]DMF·2H2O (BAO28) and [Zn(DIN)(HPT)]·2H2O (BAO29) (H2HPT = 5‑hydroxy-isophthalic acid, DIN = 1,4-di(imidazol-1-yl)naphthalene and DMF = N,N-dimethylformamide), were successfully synthesized under solvothermal conditions. Fluorescence analysis showed that BAO28 proceeded with a DIN ligand-based emissive fluorescence. More importantly, the recoverable multi-responsive fluorescent sensor BAO28 was used for fluorescent detection of imidacloprid (IMI), nitenpyram (NTP), and riboflavine (VB2) in a neutral buffer solution with high sensitivity and a low detection limit. Moreover, the sensing of the pesticides by BAO28 was mainly due to the competitive absorption of excitation and emission light by the sensor with that of the pesticides. Furthermore, for the sensing of riboflavine, in addition to the internal filtration effect (IFE) and fluorescence resonance energy transfer (FRET) mechanisms, the sensing mechanism was simultaneously attributed to photoinduced electron transfer.

Fabrication, Crystal Structures, Catalytic, and Anti-Wear Performance of 3D Zinc(II) and Cadmium(II) Coordination Polymers Based on an Ether-Bridged Tetracarboxylate Ligand

Two 3D Zn(II) and Cd(II) coordination polymers, [Zn2(µ4-dppa)(µ-dpe)(µ-H2O)]n·nH2O (1) and [Cd2(µ8-dppa)(µ-dpe)(H2O)]n (2), have been constructed hydrothermally using 4-(3,5-dicarboxyphenoxy)phthalic acid (H4dppa), 1,2-di(4-pyridyl)ethylene (dpe), and zinc or cadmium chlorides. Both compounds feature 3D network structures. Their structure and topology, thermal stability, catalytic, and anti-wear properties were investigated. Particularly, excellent catalytic performance was displayed by zinc(II)-polymer 1 in the Knoevenagel condensation reaction at room temperature.

Supramolecular promotion of chemosensing effect in a new amino-acid-derivative macrocyclic ligand toward Fe(III) and Pb(II) by Zn(II) polymerization

A fluorescent synthetic amino acid appended with an N2O2-donor macrocyclic ligand L was prepared and characterized by single-crystal X-ray diffraction (SCXRD), elemental analysis, IR, 1H and 13C NMR, fluorescence (FL), and UV–vis spectroscopy. L exhibited an FL emission quenching in the presence of Fe(III) ion and showed a limit of detection (LOD) of 5.98 × 10−6 M while the periodic addition of EDTA to the Fe(III)/L solution in DMF reversibly enhanced the FL emission. Based on the bridging role of a water tetramer cluster (WTC) in the crystal structure of L for supporting the formation of the self-assembly of L, an aggregation-caused mechanism was proposed for the observed concentration-based quenching phenomena, confirmed by FL, and 1H NMR spectroscopy. Moreover, we synthesized a new one-dimensional Zn(II) coordination polymer (CP) [Zn(LH)(H2O)(NO3)(DMSO)]n (1) consisting of paddle-wheel Zn2(COO)4 subunits and four bridged L linkers, characterized by SCXRD method. 1 was assumed to be formed by replacing the WTC in the crystal structure of L. A parallel FL behavior for L and 1 was determined, attributable to a ligand-based electronic transition. 1 was found as a more sensitive chemosensor for Fe(III) than L, based on an improved LOD of 9.74 × 10−8 M for Fe(III). Meanwhile, the promotional effect of Zn(II) in CP of 1 has overcome the chemosensing incapability of L towards Pb(II), maybe due to the ease of trans-metalation of Pb(II) with Zn(II) in 1 instead of the direct coordination with L.

A two-fold interpenetrated 2D Zn (II) coordination polymer for sensitive and stable sensing of Fe3+/nitrofurantoin

Rapid, sensitive and stable detection of antibiotics and heavy metal ions in water system is essential for human health. A two-fold interpenetrated 2D Zn (II) coordination polymer (CP) [Zn(BIPY)(bibp)]n (H2BIPY = 6-(5-carboxypyridin-2-yl) pyridine-3- carboxylic acid], bibp = 4,4′-bis (imidazolyl) biphenyl) has been designed by a rigid ligand and zinc nitrate. The excellent thermodynamic stability of Zn-CP can be confirmed by thermogravimetric (TG) and powder X-ray diffraction (PXRD) analyses. Meanwhile, fluorescence sensing experiments displayed Zn-CP can sensitively sensing of Fe3+/nitrofurantoin (NFT) with limit of detection of 1.33 μM/0.84 μM. The sensing mechanisms of Zn-CP for Fe3+/NFT are attributed to competitive absorption and static quenching between Zn-CP and Fe3+/NFT, and electron transfer from Zn-CP to NFT, which can be confirmed by patterns of PXRD, ultraviolet visible (UV–vis) spectra, fluorescence lifetime decay experiments, X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) calculations. In addition, anti-interference experiments and cyclic experiments showed that Zn-CP have excellent fluorescence sensing selectivity and stability for Fe3+/NFT.

A New Zn(II) Compound: Luminescent Property and Promoting Knee Cartilage Repair by Modulating Iron Death.

The hydrothermal reactions of bis{6-{5-methyl-1H,7H-[1,2,4]triazolo[1,5-a]pyrimidin-7-one}}methane (L) and Zn(NO3)2·6H2O at 180 ℃ afforded a novel Zn(II) coordination polymer (CP), that is, {[Zn2(L)(µ2-O)2]·3H2O}n (1), which further characterized via Single crystal X-ray diffraction (SCXRD), elemental analysis (EA), powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA). Besides, this CP reveals strong luminescence that may be caused by the charge transfer within the ligand. In biological study, the new compound was evaluated for its protective effect on chondrocytes. This compound significantly up-regulated GPX4 and down-regulated HO-1 mRNA levels, thereby inhibiting iron death in chondrocytes.

Two different 2D Zn (II) coordination polymers for highly selective detection of 2, 4, 6-trinitrophenol, tetracycline and fluazinam

Two new Zn(II) coordination polymers, namely, {[Zn2(L)(4,4′-bip)2] ·4H2O} n (1) {[Zn (H2L) (1,2-die)] · H2O} n (2) [H4L = 5, 5′-(ethane-1, 2-diyl) diisophthalic acid, 4, 4′-bip = 4, 4′ - bis (1-imidazolyl) biphenyl, 1, 2-die = 1,2-di(pyridin-4-yl)ethene] have been synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction, thermogravimetric analysis, IR spectra and fluorescent analysis. Coordination polymers 1 and 2 are 2D network structures. They both have 3D supramolecular structures based on the interspersion of 2D networks. They can detect 2, 4, 6-trinitrophenol (TNP), tetracycline (TET) and fluazinam (FLU) by fluorescence quenching. And the possible reasons for the quenching of TNP, TET, and FLU were discussed in detail, which may be energy resonance transfer. These new zinc coordination polymers could be used multifunctional sensors on NACs, antibiotics and pesticides in the future. In addition, the results of fluorescence sensing experiments show that Zn(II) coordination polymers composed of different auxiliary N donors have significant influence on the detection limits.

Ultrafast turn-on/turn-off fluorescent detection of hazardous metals and highly efficient iodine capture using Zn(II) coordination polymers

In this work, Zn-based coordination polymers (CPs) [Zn(dpe)Cl2]n (HT-5) and [Zn(tmdp)Cl2]n (HT-6) have been synthesized solvothermally using 1,2-di(4-pyridyl)ethylene (dpe), and 4,4′- trimethylenedipyridyl (tmdp) as linkers. HT-5 and HT-6 were characterized using elemental analysis, FTIR, PXRD, SEM, EDS, and crystallographic studies. The HT-5 and HT-6 adsorbents have been employed for removing toxic iodine from a hexane solution with a capacity of 182 mg g−1, while 129 mg g−1 in the vapor phase for HT-5 within 48 h. The presence of π-electron-rich moieties in the HT-5 and HT-6 frameworks was responsible for effective iodine adsorption. Furthermore, HT-5 and HT-6 are not only utilized to capture iodine, they may be used as sensitive sensors that emit fluorescence. The fluorescence “turn-off” response for Mn7+ and Cr6+ ions and a fluorescence “turn-on” response in the case of Hg2+ ions are observed for the CPs. Under optimal conditions, the limit of detection (LOD) of HT-5 is 1.4 µM, 1.1 µM, and 1.3 nM for Mn7+, Cr6+, and Hg2+, respectively. As a result, the developed Zn based CPs can serve as an efficient material for iodine capture as well as fluorescent sensor for detection of hazardous metal ions.

Structures and luminescence properties of one co‐edge bi‐rhomboid [Zn6] based 1D stair‐stepping polymer and one quasi‐linear tetra‐nuclear [Cd4] cluster with orotic acid

AbstractWith orotic acid (H3OA) as building ligand, one one‐dimensional (1D) Zn(II) coordination polymer, [Zn2(HOA)(μ2‐OH)(μ3‐OH)(H2O)]n (1), and one tetra‐nuclear Cd(II) cluster, [Cd4(HOA)4(μ2‐OH2)2(H2O)10] (2), have been synthesized at 90 °C and room temperature, respectively. Single‐crystal X‐ray diffraction analyses reveal that complex 1 has an 1D stair‐stepping structure consisting of co‐edge bi‐rhomboid [Zn6] structural motif and μ3‐HOA2− linker, and 2 owns a quasi‐linear tetra‐nuclear [Cd4] cluster structure fastened by μ2‐OH2 and HOA2− fixators. The solid‐state photophysical properties were investigated and 1 and 2 display a distinct emission centered at 374 and 393 nm, respectively.

Two new Zn(II) and Cd(II) coordination polymers derived from 1,3,5-tris(3-carbonylphenyloxy)benzene and 4,4′-bis(imidazolyl)biphenyl ligands: Syntheses, structure and luminescent sensing of antibiotics

Two new coordination polymers with formulae [Zn(HL)(bb)]n (1) and [Cd(HL)(bb)]n (2) (H3L = 1,3,5-tris(3-carbonylphenyloxy)benzene and bb = 4,4′-bis(imidazolyl)biphenyl) have been synthesized solvothermally and structurally characterized by elemental analysis, IR, single crystal X-ray diffraction and thermal analyses. Single crystal X-ray diffraction studies reveal that compounds 1 and 2 show similar three-fold interpenetrating 4-connected 2D framework structure with the sql topological net and the Schläfli symbol of {44·62} and are further extended into 3D supramolecular network by inter-molecular hydrogen bonding. Compound 1 have been used as turn-off luminescent sensor and displayed sensitive and selective luminescence sensing for nitrofurazone antibiotic (NFZ) with Ksv of 0.87 × 103 M−1 and 1.98 ppm limit of detection (LOD). The plausible mechanistic pathway for the detrioration in the luminescent intensity of 1 in presence of antibiotics have been explained with the help of theoretical calculations. The calculations indicated that the decline in fluorescence intensity of 1 was accredited to the electron/energy transfer as well as weak interactions operating between 1 and antibiotic.

A novel Zn(II) coordination polymer with mixed N- and O-donor linker: Room temperature synthesis, comprehensive characterization and Hirshfeld surface analysis

The present study describes the room temperature synthesis of a new two-dimensional (2D) coordination polymer (CP) having the formula [Zn(H-PCA)2]n (CP1), where H-PCA stands for 4-pyrazolecarboxylate. The mixture of Zn(OAc)2·2H2O and multitopic mixed N- and O-donor 4-pyrazolecarboxylic acid (H2-PCA) were self-assembled in a one-pot in methanol. The synthesis produced good yield and purity, and this method makes it simple to obtain multigram quantities of CP1 within a short period. Notably, this synthetic method selectively deprotonates the carboxylic acid group while maintaining pyrazole moiety in its protonated form. CP1 has been characterized by single-crystal X-ray diffraction, FTIR spectroscopy, elemental analysis, scanning electron microscopy, thermogravimetric analysis and powder X-ray diffraction. CP1 exhibits a 4-connected, 2-fold interpenetrated 2D network with the point symbol {44.62} – sql net topology. Due to the presence of the protonated pyrazole, these 2D layers further extended into a three-dimensional (3D) non-porous supramolecular network through strong 'intermolecular' NH···O hydrogen bonds between adjacent layers. Additionally, a 3D Hirshfeld Surface analysis accompanied by quantitative 2D-fingerprint plots was also investigated to explore the 'intermolecular' interactions.

Concentration mediated structural modulation in a family of mixed-ligand coordination polymers: Structure, sorption and luminescence study

A series of mixed-ligands Zn(II) coordination polymers (CPs) have contracted by varying the relative ratio of two ligands. A linear N,N′-donor ligand, trans 4,4′-azobispyridine (azbpy) and a sodium salt of tri carboxylic acid, 1,3,5-benzenetricarboxylate (Na3btc) have been used in different ratio, along with Zn(II) salt to synthesize three different mixed ligands multifunctional hydroxy bridged CPs, namely {[Zn2(μ2-OH)(azbpy)(btc)(H2O)]. (H2O)(MeOH)}n (1), {[Zn2(μ3-OH)(azbpy)1.5(btc)(H2O)].(azbpy)0.5(H2O)4}n (2), and {[Zn2.5(azbpy)(Hbtc)2(μ2-OH)(H2O)3].(H2O)3.5(MeOH)}n (3). All these CPs 1, 2 and 3 have been characterized by single crystal X-ray diffraction (SCXRD), elemental analysis, infrared (IR) spectroscopy, thermogravimetric (TG) analysis, UV–visible spectroscopy and powder X-ray diffraction (PXRD). The desolvated frameworks of 1 and 2 adsorb CO2 better, over N2, whereas, complex 3 shows reverse phenomenon. Solid state luminescence studies of these CPs display attentive fluorescence emission at room temperature. Change in those properties has been observed, which has been discussed here with structural correlation.

A two-fold interpenetrated mixed-ligands acentric 3D coordination polymer Zn(OBA)(DIB)·0.5H2O: Topological analysis, fluorescent and second-order NLO properties

Second-order nonlinear optical (NLO) materials have important applications in the realms of photoelectronics and photonics whose microstructures need to be organized into a noncentrosymmetric (NCS) structure. In this work, a mixed-ligands three-dimensional (3D) noncentrosymmetric coordination polymer Zn(OBA)(DIB)·0.5H2O (1) was hydrothermally prepared from 4, 4′-oxydibenzoic acid (H2OBA), 1, 3-di(1H-imidazol-1-yl)benzene (DIB) and Zn(NO3)2·6H2O via spontaneous resolution approach, which crystallizes in a noncentrosymmetric space group Fdd2. Compound 1 was characterized by powder X-ray diffraction (XRD), thermogravimetric (TGA) and IR analyses. The structural analysis shows that 1 is a two-fold self-interpenetrated three-dimensional (3D) network material. Single crystal X-ray diffraction and the topological analysis manifests that the topological structure of 1 belongs to a cds topological net. The measurement of the fluorescent properties of 1 and the free DIB ligand show that the emission peak at 460 nm of 1 can be attributed to the charge transition from the п bond electron to the п anti-bond orbital of the DIB ligand. The second-harmonic generation (SHG) measurement shows that the second-order NLO effect of compound 1 is approximately equivalent to that of potassium dihydrogen phosphate (KDP). Compound 1 is high thermal stable and insoluble in water and common organic solvents, making it to be a potential candidate as a second-order NLO material.

Synthesis and characterization of new 2D coordination polymers based on mixed 1,1-cyclopentanediacetate and 1,2-bis((1H-imidazol-1-yl)methyl)benzene linkers

New three Co(II), Zn(II) and Cd(II) coordination polymers (CPs), [Co(µ-cpda)(µ-obimb)]n (1), [Zn(µ-cpda)(µ-obimb)]n (2) and [Cd(µ-cpda)(µ-obimb)]n (3) [H2cpda: 1,1-cyclopentanediacetic acid, obimb: 1,2-bis((1H-imidazol-1-yl)methyl)benzene] were obtained and fully characterized by elemental analysis, fourier transform infrared spectroscopy, single crystal and powder X-ray diffractions. In addition, thermal, luminescence, topological and optical properties of the complexes were investigated. According to single crystal X-ray diffraction analysis results, complexes 1, 2 and 3 isomorphous and complex 1 and 2 demonstrated two-dimensional (2D) composed of Co(II) and Zn(II)-containing polymeric chains with distorted tetrahedral geometry. Complex 3 is a 2D coordination polymer containing a Cd(II) ion with a distorted octahedral geometry. According to the results of the topological analysis performed to determine the simplified architectures of the complexes obtained, all structures display sql/Shubnikov topology with the point symbol of (44.62).

Statement of Retraction: Synthesis and crystal structure of two new Zn(II) and Ni(II) coordination polymers with anti-ovarian cancer activity

Statement of Retraction: Synthesis and crystal structure of two new Zn(II) and Ni(II) coordination polymers with anti-ovarian cancer activity

PH-Stable Zn(II) Coordination Polymer as a Multiresponsive Turn-On and Turn-Off Fluorescent Sensor for Aqueous Medium Detection of Al(III) and Cr(VI) Oxo-Anions.

Nowadays, coordination polymers (CPs) are promising candidates as sensory materials for their high sensitivity, improved selectivity, fast responsive nature, as well as good recyclability. However, poor chemical stability often makes their practical usage limited. Herein, employing a mixed ligand approach, we constructed a chemically robust CP, {[Zn2L2(DPA)2]·3H2O}n (IITKGP-70, IITKGP stands for the Indian Institute of Technology Kharagpur), which exhibited excellent framework robustness not only in water but also over a broad range of pH solutions (pH = 3-11). The developed framework displayed high selectivity and sensitivity for the detection of trivalent Al3+ ions and toxic hexavalent Cr(VI)-oxo anions in an aqueous medium. The developed framework exhibited an aqueous medium Al3+ turn-on phenomenon with a limit of detection (LOD) value of 1.29 μM, whereas a turn-off effect was observed for toxic oxo-anions (Cr2O72- and CrO42-) having LOD values of 0.27 and 0.71 μM, respectively. Both turn-on and turn-off mechanisms are speculated via spectroscopic methods coupled with several ex situ studies. Such a multiresponsive nature (both turn-on and turn-off) for aqueous medium detection of targeted cations and anions simultaneously in a single platform coupled with high robustness, ease of scalability, recyclability, and fast-responsive nature makes IITKGP-70 highly fascinating as a sensory material for real-world applications.

Synthesis, crystal structures, photophysical and antibacterial properties of Ag(I) and Zn(II) coordination polymers based on a flexible bisacylhydrazone ligand

A flexible bisacylhydrazone ligand (H4L) was designed and synthesized from the condensation reaction of dialdehyde 3,3′-thiobis(methyiene)-bis-(5-methyl-salicylaldehyde) (b) with isonicotinic hydrazide. In the DMSO/methanol solution, two coordination polymers (CPs), formulated as {[Ag(H4L)NO3]·DMSO·2H2O}n (CP 1) and {[Zn2(H2L2-)2]·3DMSO·3H2O}n (CP 2), were synthesized from H4L with Ag(I) or Zn(II) ions, respectively. These two CPs were characterized via elemental analysis, FT-IR spectra, and single crystal X-ray determination. The results show that CP 1 exists as a 1D looped-chain polymer, while CP 2 exists as a 2D sheet polymer. The coordination configurations of the two CPs were analyzed and compared in detail, which disclose the terminal pyridyl nitrogen atoms exhibit obviously stronger coordination ability compared to other sites. In addition, photophysical, electrochemical and antibacterial properties of H4L and the two CPs were investigated.