Zn Coordination Polymers Research Articles

Hydrogen-bonded 3D like structures of Cu(II)/Zn(II) coordination polymers: photoluminescence, TDDFT study and semiconductive properties

Two Cu/Zn complexes [Cu(4,4'-bipy)(H2O)2(ClO4)2] nn(4,4'-bipy) (1) and [Zn(4,4'-bipy)(H2O)4]3 n 6n(4,4'-bipy)6n(ClO4)·2nH2O (2) (4,4'-bipy = 4,4'-bipyridine) have been prepared via hydrothermal reactions and characterized by single-crystal X-ray diffraction. Both complexes feature an infinite 1-D chain-like structural motif with the metal ions surrounded by two nitrogen atoms and four oxygen atoms to yield a octahedral configuration. Both complexes have a 3-D coordination polymer network formed by the rich hydrogen-bonding interactions. Powder photoluminescence studies reveal that they have an emission in the blue (1) or red (2) region of the light spectrum. Time-dependent density functional theory investigation discover that the nature of the emission is resulted from the ligand-to-metal charge transfer for 1, as well as ligand-to-ligand charge transfer for 2. Narrow optical band gaps of 1.43 eV (1) and 2.24 eV (2) are found by the solid-state UV/vis diffuse reflectance spectra.

Two Zn(II) coordination polymers constructed from sulfate and isomeric viologen-carboxylate ligands: Crystal structures, photochromism and ammonia vapochromism

Nowadays, the exploration of chromic materials has been highly desirable owing to their appealing applications. In this work, two Zn(II) coordination polymers constructed from sulfate and isomeric viologen-carboxylate ligands, formulated as {[Zn(L1) (SO4)](H2O)2}n (1), {[Zn(L2) (SO4) (H2O)2](H2O)3}n (2) (L1 = N-(3-carboxy(pyridin-2-yl))-4,4′-bipyridinium, L2 = N-(4-carboxypyridin-3-yl)-4,4′-bipyridinium) have been synthesized and characterized. Single crystal X-ray analyses reveal that 1 features a 2D layer structure and 2 discloses a 1D chain structure. As expected, 1 and 2 exhibit sensitive photochromic properties under xenon light irradiation due to the formation of photoinduced radicals. Moreover, 1 displays a color change detectable by the eye when exposed to ammonia vapor. These results provide some useful guidance to explore new chromic crystalline materials.

A zinc-based coordination polymer as adsorbent for removal of trichlorophenol from aqueous solution: Synthesis, sorption and DFT studies

[Zn(hba)2(tmdp)]n (1), a Zn-coordination polymer (CP), prepared by the reaction of Zn(NO3)2•6H2O, 4-hydroxybenzoic acid (Hhba) and 4,4′- trimethylenedipyridine (tmdp) was reported. The compound was characterised, using CHN, single crystal and powder X-ray diffraction analysis, FT-IR, and TGA techniques. It exhibits a square pyramidal geometry, with the zinc (II) atom coordinated to two nitrogen atoms from two tmdp ligand molecules and to three oxygen atoms from two hba molecules. The zinc (II) carboxylate units are bridged through the N-donor spacer ligand, thereby giving rise to a one-dimensional CP. PXRD analysis confirmed the purity of the bulk of (1). Compound (1) presented an adsorption capacity of 207.8 mg/g for the removal of 2,4,6-trichlorophenol (TCP) from aqueous solution. The adsorption mechanism is governed by π-π stacking and electrostatic interactions, as obtained from DFT studies. The feasibility and exothermic nature of the adsorption process is indicated by the negative binding energy obtained.

A new 2D Zn(II) coordination polymer as luminescent probe for highly selective detection of nitrofurazone

Coordination polymers (CPs) are peculiar category of materials having multidimensional framework and could be used as selective and sensitive sensors for ions and molecules. In this regard, a new Zn(II)-based coordination polymer (CP) [Zn(H2L)(H2O)2]n (1) has been derived from 1,3-bis(3,5-dicarboxylphenoxy)benzene (H4L) ligand and spectroscopically characterized alongwith single crystal X-ray diffraction. The crystallographic experiments reveal the existence of 2D layer in 1. The CP retains its framework integrity in water and exhibits luminescent property. This newly designed CP has been used as luminescent sensor to detect antibiotics by the decline in its luminescence intensity. The sensing experiments indicated that the CP displays sensitive and selective sensing against nitrofurazone (NZF) with limit of detection (LOD) of 1.12 ppm and Ksv value of 2.41 × 103 M−1. The experimentally observed decline in the luminescence intensity of 1 in presence of antibiotics has been explained with the help of theoretical calculations.

2D network structure of zinc(II) complex: A new easily accessible and efficient catalyst for the synthesis of pyrazoles

AbstractA Zn(II) coordination polymer {[Zn3(paz)(btc)2(H2O)8]·4H2O}n (noted as ZnPB), where paz = pyrazine, H3btc = trimesic acid, was synthesized and characterized by single‐crystal X‐ray diffraction, elemental analysis, infrared spectroscopy and powder X‐ray diffraction analyses. ZnPB shows a (3,3)‐connected 2D network with a point symbol of (63)2. Hydrogen bonds and π···π interactions connect adjacent 2D network to form a 3D packing structure. This compound exhibits excellent catalytic activity in the reaction of condensation and cyclization of sulfonyl hydrazides with 1,3‐diketones for the synthesis of pyrazoles. This solvent‐free and halogen‐free catalytic system represents an effective economic and environmentally friendly method for the construction of pyrazoles.

Luminescent, Helical and Highly Stable Zn(II) and Cd(II) Coordination Polymers: Structural Diversity and Selective Sensing of 4‐Nitroaniline in Water

AbstractUtilizing a bent bis(naphthalene) and hydroxy‐based dicarboxylate linker (mbhna) and two different tridentate polypyridyl ligands (bpma and bpta), four new coordination polymers (CPs) of Zn(II) and Cd(II) namely, [Zn(mbhna)(bpma)]n (1) {[Cd(mbhna)(bpma)].DMF}n (2) [Zn(mbhna)(bpta)]n (3) {[Cd(mbhna)(bpta)(CH3OH)]}n (4), are reported. Based on their solid‐state molecular structures determined by single‐crystal X‐ray diffractometry, all are found to be helical 1D CP; interestingly, 4 crystallizes in a chiral space group, showcasing the formation of a chiral CP from achiral components. For the presence of naphthalene moieties in mbhna, their excellent emissive nature is studied in different solvents and further utilized to selectively detect aromatic amines, particularly 4‐nitroaniline in water with detection limits at the ppm level. Utilizing the Stern‐Volmer plots, spectral overlap, and competitive test, their mechanism of action has been established. Furthermore, these are recyclable with good stability after sensing experiments.

Novel Zn(II) coordination polymer based on a semi-rigid tricarboxylate acid ligand: synthsis, structure, and fluorescence recognition of acetylacetone and chromium(VI) anions

A novel Zn(II)-coordination polymer [Zn(HL)(bpe)0.5]·H2O] (CP 1) (H3L ​= ​4-(2′,3′-dicarboxylphenoxy) benzoic acid, bpe ​= ​1,2-bis(4-pyridyl) ethylene) has been successfully prepared. In CP 1, a dinuclear Zn2(C2OO)4 secondary building unit (SBU) is found, which is further connected by HL2− ligand to induce a two-dimensional (2-D) layer cage structure with (4•52) (4•53•72) topology. CP 1 exhibits excellent fluorescence property. Interestingly, it can also act as a highly efficient fluorescence based sensor for simultaneously detecting acetylacetone (Hacac) and oxoanion Cr(VI) ions with high sensitivity and selectivity in aqueous solution through fluorescence quenching. The detection limits of CP 1 toward Hacac and Cr2O72−, CrO42− are as low as 1.92 ​ppm, 2.23 ​μM and 2.57 ​μM, respectively. Furthermore, the possible sensing mechanism in both proposed sensing systems has also been discussed in more detail.

Co(II) and Zn(II) coordination polymers: selective detection of Fe(III) ion and treatment activity on renal calculus

Co(II) and Zn(II) coordination polymers: selective detection of Fe(III) ion and treatment activity on renal calculus

A hydrolytically stable Zn(II) coordination polymer based on a new imidazolyl-pyrazolyl heterotopic ligand as a scavenger of MnO4− and a luminescent sensor for MnO4− and Cr2O72−

Reactions of Zn(NO3)2 with a new rigid tripodal imidazolyl-pyrazolyl heterotopic ligand, 4-(3,5-di-imidazol-1-yl-phenyl)-1H-pyrazole (HDIPP), result in a new compound with the formula {[Zn(HDIPP)2]·2NO3}n (Zn-HDIPP). Zn-HDIPP exhibits a 3D framework with a three-fold interpenetrating dia network topology. It shows high hydrolytic stability in the pH range 3 to 11. In addition, Zn-HDIPP displays useful properties including (i) the removal of MnO4− from water with a capacity of 550 mg/g and with high selectivity when other anions are also present and (ii) the luminescence quenching detection of MnO4− and Cr2O72− in water via energy-transfer and competitive absorption mechanisms. These results show that Zn-HDIPP has the potential to be used in detection and removal of pollutants in water.

Preparation, characterization and antibacterial activity of a novel Zn(II) coordination polymer derived from carboxylic acid

Zn coordination polymer, [Zn2(DABA)3(CH3OH)] (DABA= 4-Dimethylaminobenzoic acid) (ZCP), was successfully synthesized with DABA and Zn(NO3)2•6H2O in a manner of solvothermal synthesis. The exact structure of ZCP was confirmed by thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR) and single crystal X-ray diffraction. In addition, experiments showed that ZCP possessed antibacterial activity against Escherichia coli in vitro. The antibacterial mechanism of ZCP was discussed in this study, which was associated with the generation of reactive oxygen species (ROS) in bacteria. Our findings could be helpful for a better understanding of the potential of ZCP as antibacterial agents, which had prospective applications for microbial infection in patients.

Dual luminescent coordination polymers based on flexible aliphatic carboxylate ligands supplemented by rigid bipyridyl ligands for 2,4-dinitrophenol (DNP) and iron(III) ion detection

Based on flexible aliphatic carboxylate ligands supplemented by rigid bipyridyl ligands with isomerized structures, three novel Zn(II) coordination polymers, namely Zn2(dpe)(glutarate)2(H2O)2 (1), Zn2(glutarate)2(tdpe)2(H2O)2 (2) and Zn(H2O)(succinate)(tdpe)2 (3) [dpe = 1,2-di(4-pyridyl)ethylene, tdpe = trans-1-(2-pyridyl)-2-(4-pyridyl)ethylene)], were synthesized by appropriate methods. The crystallographic data of all the complexes present diverse geometries of the Zn(II) centers. There are two independent Zn(II) ions where one is intermediate between square pyramidal and trigonal pyramidal and the other is distorted tetrahedral [in 1] or distorted octahedral [in 2 and 3]. Both carboxylate ligands act as bridging ligands with various coordination modes to build up the main structures, whereas the bipyridyl ligands show only coordination of the 4-pyridyl site with the metal centers, indicating that only dpe acts as a bridging ligand, building up the principal framework in 1. The tdpe ligand presents a monodentate coordination mode in the other two complexes. The structures of all complexes indicate that the coexistence of two ligand types could support higher dimensionalities in the complexes. Complex 1 was further used as a nitroaromatic compound (NAC) and a heavy metal ion sensor. The complex showed highly sensitive and selective sensing of 2,4-dinitrophenol (DNP) and Fe(III) ions, based on its fluorescence quenching effect.

Synthesis and crystal structures of Zn(II) and Cd(II) coordination polymers derived from the flexible N-(4-carboxyphenyl)iminodiacetic acid and auxiliary ligands

Abstract Two coordination polymers [Cd3(CPIDA)2(bib)(H2O)2] n 1 and {[Zn6(CPIDA)4(bix)3]·8H2O} n 2 (H3CPIDA = N-(4-carboxyphenyl) iminodiacetic acid, bib = 1,4-bis(N-imidazolyl)butane, bix = 1,4-bis(imidazol-1-ylmethyl)benzene), have been hydrothermally synthesized and characterized by analytical and IR spectroscopic data. Compound 1 displays an interesting 3D framework with trinodal (4,5)-connected topology, consisting of (4,4) rectangular grid double layers linked by trans-bib ligands. In 2, the corrugated nets with couples of central symmetrical chains constructed by CPIDA3− and bridging trans-bix ligands are pillared by infinite tubes made from CPIDA3− and cis-bix ligands to build a new 3D porous framework with parallelogram-shaped channels, exhibiting a pentanodal (3,4)-connected topology. Moreover, compounds 1 and 2 show intense solid state fluorescence at room temperature.

Sensing and photocatalytic properties of two zinc(II) coordination polymers containing bis(benzimidazole) ligands

Two new ternary Zn(II) coordination polymers, namely {[Zn(L1)(PA)].H2O}n (1) and [Zn(L2)(PA)]n (2) (L1 = 1,3-bis(benzimidazol-1-ylmethyl)benzene, L2 = 1,4-bis(benzimidazol-1-ylmethyl)benzene, H2PA = pimelic acid), were hydrothermally synthesized and characterized. 1 shows a 1D ladder-like chain and can further form 2D supramolecular framework by π − π stacking interactions, while 2 exhibits a 2D (6,3) layer. 1 and 2 show excellent photocatalytic performance for the degradation of methyl violet under UV irradiation, the degradation efficiencies of 1 and 2 can reach 98.5% and 94.8% after 150 min, respectively. Furthermore, 1 and 2 can selectively detect acetylacetone (acac)/Fe3+ and acac/MnO4− ions, separately, via the luminescence quenching process.

A 2-D Zn(II) coordination polymer based on 4,5-imidazoledicarboxylate and bis(benzimidazole) ligands: synthesis, crystal structure and fluorescence properties

Abstract In this work, a new type of zinc(II) coordination polymer {[Zn(HIDC)(BBM)0.5]·H2O} n (Zn-CP) was synthesized using 4,5-imidazoledicarboxylic acid (H3IDC) and 2,2-(1,4-butanediyl)bis-1,3-benzimidazole (BBM) under hydrothermal conditions. Its structure has been characterized by infrared spectroscopy, elemental analysis and single crystal X-ray diffraction analysis. The Zn(II) ion is linked by the HIDC2− ligand to form a zigzag chain by chelating and bridging, and then linked by BBM to form a layered network structure. Adjacent layers are further connected by hydrogen bond interaction to form a 3-D supramolecular framework. The solid-state fluorescence performance of Zn-CP shows that compared with free H3IDC ligand, its fluorescence intensity is significantly enhanced.

Two Zn(II) Coordination Polymers: Luminescent Sensing Property and Treatment Activity on Uterine Leiomyomas by Reducing TGF-β Releasing and mmp-3 and mmp-7 Expression

Under solvothermal conditions, two new Zn(II)-based coordination polymers, namely {[Zn(tptc)0.5(2,2′-bpy)]·dioxane}n (1, H4tptc = p-terphenyl-2,2″,5″,5‴-tetracarboxylate acid, 2,2′-bpy = 2,2′-bipyridine) and [Zn(tptc)0.5(bib)]n (2, bib = 1,3-bis((imidazol-1-yl) benzene), have been synthesized using the mixed-ligand approach. Furthermore, the luminescence studies show that complex 2 can test acetylacetone selectively and sensitively, and the detection limit is 1.72 ppm. In addition, we evaluated the compounds therapeutic effect against uterine leiomyomas. The uterine leiomyomas rats model was established, the compound 1 and compound 2 was used for treatment. The detection of the transforming growth factor-β (TGF-β) releasing from endometrial stromal cells into plasma was detected with an enzyme linked immunosorbent assay (ELISA) detection kit. Then, the mmp-3 and mmp-7 relative expression levels in the uterine smooth muscle cells after compound treatment were measured by the reverse transcription-polymerase chain reaction (RT-PCR).

Structure and reversible crystal-to-crystal transformations of a zinc(II) coordination polymer constructed from an imide-based dicarboxylic acid

An imide-based O-donor ligand, 4-carboxyphenyl-1,3-dioxoisoindoline-5-carboxylic acid (H2In-4-ba), and one Zn(II) coordination polymer, [Zn(In-4-ba)(py)2]n (1, py ​= ​pyridine), have been synthesized. Single-crystal X-ray diffraction indicates that 1 has a quasi-31 helical chain structure, which shows one-dimensional to two-dimensional (1D → 2D) extension to be a homochiral layer of consecutively interweaving poly-helices with the same helicity. Coexistence of such homochiral layers in opposite chirality makes individual crystal of 1 to be in a racemic manner. Thermogravimetric (TG) analysis indicated that 1 shows high thermal stability approaching 440 ​°C. Thermal activation of 1 gives a desolvated phase, [Zn(In-4-ba)]n (1′), as supported by TG trace. Of particular note, reversible crystal-to-crystal transformations between solvated 1 and desolvated 1′ have been achieved upon decoordination and recoordination of the py ligands, as evidenced by XRPD patterns, IR spectra, and TG diagrams. The photoluminescence properties of as-synthesized 1, desolvated 1′, and resolvated 1′/py have also been studied. All of them exhibit an emission band centered at 486, 492, and 486 ​nm, respectively, which is originated from the ligand-centered charge transfer. Further, the emission intensity of 1′ is weaker than that of 1 and 1′/py, implying the influence of coordinated py ligands and/or structure regulation on photoluminescence.

Retracted: A new Zn(II) coordination polymer: Selective detection of Fe3+ and treatment activity of the exercise induced traumatic osteoarthritis by reducing reactive oxygen species production

AbstractThrough utilizing the fluorescent ligand of tris(4‐(triazol‐1‐yl)phenyl)amine, an innovative Zn(II)‐based coordination polymer formulated as {[Zn2(μ‐OH2)(TTPA)(DTDN)2·DMF]·H2O}n (1, DTDN = 6,6′‐dithiodinicotinate and TTPA = tris(4‐(1H‐1,2,4‐triazol‐1‐yl)phenyl)amine) has been successfully prepared by using the H2DTDN as the auxiliary ligand under the solvothermal reaction conditions and structurally characterized. According to the results of fluorescence spectrum analysis, complex 1 has high sensitivity and selectivity for Fe3+ ion. It can effectively detect Fe3+, the linear range is from 0 to 1,000 μM, and the detection limit of Fe3+ is 8.65 nM. Its treatment activity against exercise induced traumatic osteoarthritis was estimated and its detail mechanism was also investigated in meantime. First, the detection assay of reactive oxygen species (ROS) was implemented for the assessment of the ROS levels produced in the articular soft tissue after compound treatment. Besides, the reverse transcription‐polymerase chain reaction (RT‐PCR) was also conducted and the genes relative expression related with ROS production was measured after compound exposure.

Photocatalytic organic dye by two new coordination polymers with flexible dicarboxylate and different N-donor linkage

Two new Zn(II) coordination polymers (CPs) with [Zn(L)(2,2′-bipy)] (1) and [Zn(L)(bbi)0.5] (2) (H2L = 3,3′-(1,2-phenylenebis(methyleneoxy)) dibenzoic acid, bbi = 1,1′-(1,4-butanediyl)bis(imidazole), 2,2,’-bipy = 2,2,’-bipyridine), have been solvothermally prepared. They exhibited 2D layer and 1D helical networks through the connectivity of Zn atoms and phenolic-oxygen containing branches of the flexible linkages. The N-donor ligand play a distinct effect in the formation of these mortifies. Both of them showed efficient photocatalytic performances to degrade methyl violet (MV) under UV irradiation. The percentage degradation of MV are 64.55% in presence of CP 1 while it is 78.54% with 2 as photocatalyst after 100 min of UV irradiation. The final degradation products were detected using LC–MS and the possible disassemble pathways for the degradation of dyes were discussed. The plausible photocatalytic mechanism through which both CPs displayed photocatalysis of MV have been explained using theoretical calculations.

Dual Luminescent Coordination Polymers Based on Flexible Aliphatic Carboxylate Ligands Supplementing by Rigid Bipyridyl Ligands for 2,4-Dinitrophenol (DNP) and Iron (III) Ion Detections

Based on flexible aliphatic carboxylate ligands supplementing by isomerized structure of rigid bipyridyl ligands, three novel Zn(II) coordination polymers, namely Zn 2 (dpe)(glutarate) 2 (H 2 O) 2 (1), Zn 2 (glutarate) 2 (tdpe) 2 (H 2 O) 2 (2), and Zn(H 2 O)(succinate)(tdpe) 2 (3) (dpe = 1,2-di(4-pyridyl)ethylene, tdpe = trans-1-(2-pyridyl)-2-(4-pyridyl)ethylene)), have been synthesized by appropriate methods. The crystallographic data of all complexes presented the diverse geometries of Zn(II) center such as two independent of square pyramidal and tetrahedral (in (1)), trigonal bipyramidal (in (2)), and octahedral (in (3)). Both the carboxylate ligands act as bridging ligands with the various coordination mode to build up the main structures. While bipyridyl ligand showed only 4-pyridyl site in coordination bond with metal center providing only dpe acted as bridging ligand to build up the principal framework in (1). Whereas tdpe ligand presented monodentate coordination mode in the other. All structures of complexes indicated that the coexistence of two ligand types could support the higher dimensionality in the complexes. Complex 1 was further used as nitro-aromatic compounds (NACs) and heavy metal ion sensors. It shows highly sensitive and selective sensing to 2,4-dinitrophenol (DNP), and Fe(III) ion, respectively based on fluorescence quenching effect.

Stable 2D Zn(II) coordination polymer: selective detection of Fe3+ ion and treatment activity on psoriasis metabolic syndrome

ABSTRACT With the reaction between 1,3,5-tris(2-methylimidazol-1-yl)benzene (timb), a designed tripodal connector and Zn(NO3)2 · 6H2O in the presence of a hydroxyl functionalised carboxylate ligand isophthalic acid (OH-H2IPA), a novel luminescent coordination polymer (CP) containing Zn(II) ions as nodes was created through applying the reaction of solvothermal method, and its chemical formula is {[Zn5(timb)4(OH–IPA)4]·2NO3 · 2DMA·2H2O}n (1). Because of complex 1 excellent photoluminescence performances and water stability, it reveals the phenomenon of luminescence turn-off for the Fe3+ cation, and the value of Ksv is 9.59 × 103 M−1 (R2 = 0.9913). The application values of the new compound and its ligands on the psoriasis metabolic syndrome were finally evaluated.