Silver Coordination Polymers Research Articles

Synthesis of a tetratopic bisphosphine ligand derived from pyrimidine and its incorporation into gold and silver coordination polymers

Herein we present the synthesis of a tetratopic bisphosphine ligand derived from 4,6-disubstituted pyrimidine scaffold. This new ligand (2) was doubly alkylated using iodomethane to give bisphosphonium dication (3) as an iodide salt, and was also coordinated to both gold(I) chloride to give the metal complex (4) and to silver(I) triflate to give a coordination polymer (5), respectively. All compounds have been fully characterized using multinuclear NMR spectroscopy as well as single crystal X-ray diffraction. Gold complex 4 was also found to exhibit weak emission at λmax = 530 nm due to Au(I)–Au(I) aurophilic interactions. Additionally we demonstrated that bisphosphine ligand 2 can be used as a tetratopic ligand, as evidenced by the formation of the coordination polymer 5 in which both phosphine → silver and nitrogen → silver interactions were observed.

Ultrasonic assisted structures and biological characteristics of nanoscale silver coordination polymers with cyanide, azide and 4,4\\-bipyridine ligands

Ultrasonic self-assembly method was utilized to prepare new nano supramolecular coordination polymers (SCPs), 3∞[AgN3(bpy)], NSCP1 and 3∞[(AgCN)2 (bpy)], NSCP2 [bpy= 4,4\\-bipyridine] while the single crystals were prepared at ambient conditions. The silver atom in 1 acquires square planer geometry via coordination to four nitrogen atoms while NSCP2 contains two crystallographically different silver atoms adopting distorted trigonal planar geometry. The structures extend via corrugated catenated (AgN3) or (AgCN) chains which are linked by bpy forming 2D-layer structure. The 2D-layers are interconnected by π–π stacking, H- bonds and argentophilic interactions creating 3D-network structure. TEM images support nanoscale particles of NSCPs1 and 2. NSCPs 1 and 2 had been utilized as potent anticancer and anti-pathogenic micro-organisms. In vitro cytotoxicity and cell viable activity of the NSCPs1 and 2 had been studied against a set of different human cancer cell lines. The higher level of the NSCPs cytotoxicity was recorded against MCF-7 and HePG2 cells. Also, they own a good ability to inhibit the growth of the tested neoplastic cells and a poor effect on the normal cells in comparison with the results of cisplatin. Also, antioxidant activities, erythrocyte hemolysis, DNA binding and antimicrobial activities had been investigated.

Hybrid Silver(I)-Doped Soybean Oil and Potato Starch Biopolymer Films to Combat Bacterial Biofilms.

This study describes the preparation, characterization, and antimicrobial properties of novel hybrid biopolymer materials doped with bioactive silver(I) coordination polymers (bioCPs). Two new bioCPs, [Ag2(μ6-hfa)]n (1) and [Ag2(μ4-nda)(H2O)2]n (2), were assembled from Ag2O and homophthalic (H2hfa) or 2,6-naphthalenedicarboxylic (H2nda) acids as unexplored building blocks. Their structures feature 2D metal-organic and supramolecular networks with 3,6L64 or sql topology. Both compounds act as active antimicrobial agents for producing bioCP-doped biopolymer films based on epoxidized soybean oil acrylate (SBO) or potato starch (PS) as model biopolymer materials with a different rate of degradability and silver release. BioCPs and their hybrid biopolymer films (1@[SBO]n, 2@[SBO]n, 1@[PS]n, and 2@[PS]n) with a very low loading of coordination polymer (0.05-0.5 wt %) show remarkable antimicrobial activity against Staphylococcus aureus and Staphylococcus epidermidis (Gram-positive) and Escherichia coli and Pseudomonas aeruginosa (Gram-negative) bacteria. Biopolymer films also effectively impair the formation of bacterial biofilms, allowing total biofilm inhibition in several cases. By reporting on new bioCPs and biopolymer films obtained from renewable biofeedstocks (soybean oil and PS), this study blends highly important research directions and widens a limited antimicrobial application of bioCPs and derived functional materials. This research thus opens up the perspectives for designing hybrid biopolymer films with outstanding bioactivity against bacterial biofilms.

Solvent media as the driving force in the formation of one-dimensional silver(I) coordination polymers with 2-methylidene-1,3-bis(nicotinoyloxy)propane.

Two kinds of silver(I) coordination polymers consisting of the same chemical composition, [Ag(CF3SO3)(L)] [L is 2-methylidene-1,3-bis(nicotinoyloxy)propane], were synthesized and characterized by infrared (IR) and photoluminescence (PL) spectroscopy, elemental and thermal analyses, and single-crystal X-ray diffractometry; these are catena-poly[[(trifluoromethanesulfonato-κO)silver(I)]-μ-2-methylenepropane-1,3-diyl dinicotinate-κ2N:N'], [Ag(CF3SO3)(C16H14N2O4)]n, and its chloroform monosolvate, {[Ag(CF3SO3)(C16H14N2O4)]·CHCl3}n. The X-ray crystallographic measurements revealed that the silver(I) compounds exhibit one-dimensional sinusoidal or helical molecular structures depending on the solvent used for crystallization. Self-assembly in a methanol/chloroform mixture produces the sinusoidal molecular strand, whereas recrystallization from acetonitrile medium affords a racemic mixture of the helical strands. These compounds display a fluorescence emission arising from both the ligand-centred transition and the ligand-to-metal charge transfer (LMCT) in the solid state under ambient conditions.

Ultrasound-assisted synthesis and biological activity of nanosized supramolecular coordination polymers of silver(I) with chloride, thiocyanate, and 4,4′-bipyridine ligands

Nanosized crystals of coordination polymers (SCPs) [AgCl(bpy)2] (1) (bpy = 4,4′-bipyridine) and [AgSCN(bpy)0,5] (2) were prepared by precipitation method with ultrasonication. The silver atom acquires trigonal bipyramidal topology via coordination to 3 chloride atoms and 2 nitrogen atoms of 2 bpy ligands forming two fused 4-cycles [Ag2Cl2] for SCP1. Compound 1 is a 2D coordination polymer consisting of 1D ribbons [Ag2Cl2] interconnected by bpy linkers on both sides of the layer. The structure of SCP1 extends to 3D via the formation of successive 2D-layers connected by van der Waals interactions. The coordination polymer 2 has the 3D structure consisting of parallel 2D layers [Ag(SCN)2] interconnected by bpy linkers into the framework. The structure of 2 is further stabilized by argentophilic interactions. TEM shows nano sizes of the particles of 1 and 2. Cytotoxicity and cell viable activity of the nanosized 1 and 2 were investigated in vitro against a set of different human cancer cell lines. DNA binding ability of 1 and 2 was done by Methyl green displacement. ABTS inhibition and hemolysis activity experiments were used for checking Antioxidant activity of 1 and 2. Antimicrobial activity of the nanosized 1 and 2 was carried out against some bacterial strains.

Chiral Self-Assembly, Electrochemical and Gas Adsorption Properties of Two 1d Silver(I) Coordination Polymers Constructed from Racemic Helical Ligands

Chiral Self-Assembly, Electrochemical and Gas Adsorption Properties of Two 1d Silver(I) Coordination Polymers Constructed from Racemic Helical Ligands

Synthesis of bis(2-pyrazinyl)selenide and its coordination polymer with silver(I) via both solution and solventless mechanochemical grinding route

Synthesis and characterization of an organo-selenium compound, bis(pyrazinyl)selenide is presented which was further employed as a linker for silver(I) coordination polymer. Accordingly, it was reacted with AgBF4 to obtain its coordination polymer of composition, [Ag(pyz2Se)](BF4)·H2O. Crystallographic structure elucidation reveals that the resulting compound is a two-dimensional coordination polymer. Each silver(I) centre possesses coordination number of 5, defined by two selenium and three nitrogen donors, and it constitutes in a distorted trigonal pyramidal coordination sphere. One pyrazinyl ring bridges two Ag(I) by both of its N-atoms, while for other pyrazinyl ring, only N-atom participate in coordination. The BF4− anion present in the lattice balances the charge. In addition, there is a water molecule present in the crystal lattice. The idle N-atom, which does not take part in coordination, forms hydrogen bonding interaction with the water molecule. More interestingly, this coordination polymer can be obtained just by grinding the ingredients on a mortar, which offer a solventless green synthesis.

Determination of Arsenic Content in Water Using a Silver Coordination Polymer.

In this report, we describe a practical method for the colorimetric determination of dissolved inorganic arsenic content in water samples, using a silver coordination polymer as the sensing material. We demonstrate that a crystalline polymer framework can be used to stabilize silver(I) ions, greatly reducing both photosensitivity and water solubility, while still affording sufficient reactivity to detect arsenic in water samples at low parts-per-billion (ppb) levels. Test strips fabricated with the silver-based polymer are shown to be effective for field tests of groundwater under real-world operating conditions and display performance that is competitive with commercially available mercury-based test strips. Spectroscopic methods are also used to probe the reaction products formed, in order to better understand the sensing mechanism. Thus, our work provides the foundation for an improved field test that could be deployed to help manage groundwater usage in regions where arsenic contamination is problematic but sophisticated lab testing is not readily available.

Self-Assembly and Multifaceted Bioactivity of a Silver(I) Quinolinate Coordination Polymer.

Coordination polymers have emerged as a new class of potent biologically active agents due to a variety of important characteristics such as the presence of bioactive metal centers and linkers, low toxicity, stability, tailorable structures, and bioavailability. The research on intermediate metabolites has also been explored with implications toward the development of selective anticancer, antimicrobial, and antiviral therapeutic strategies. In particular, quinolinic acid (H2quin) is a recognized metabolite in kynurenine pathway and potent neurotoxic molecule, which has been selected in this study as a bioactive building block for assembling a new silver(I) coordination polymer, [Ag(Hquin)(μ-PTA)]n·H2O (1). This product has been prepared from silver oxide, H2quin, and 1,3,5-triaza-7-phosphaadamantane (PTA), and fully characterized by standard methods including single-crystal X-ray diffraction. Compound 1 has revealed distinctive bioactive features, namely (i) a remarkable antiviral activity against herpes simplex virus type 1 (HSV-1) and adenovirus 36 (Ad-36), (ii) a significant antibacterial activity against clinically important bacteria (Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa), and (iii) a selective cytotoxicity against HeLa (human cervix carcinoma) cell line. The present work widens a growing family of bioactive coordination polymers with potent antiviral, antibacterial, and antiproliferative activity.

Two 1D Silver(I) Coordination Polymers with 1,3‐Bis(4‐pyridyl) propane and Aromatic Carboxylate Anions: Synthesis, Structure and Photocatalytic Behavior

AbstractTwo coordination polymers, {[Ag(bpp)]6(tma)2.28(H2O)}n (1) and {[Ag4(bpp)4(bda)2].12(H2O)}n (2) (where bpp=1,3‐bis(4‐pyridyl) propane, H3tma=trimesic acid, H2bda=1,3‐benzenediacetic acid), have been synthesized and structurally characterized. In both the compounds the metal ions are connected by bridging dipyridine ligands to form cationic undulated 1D coordination polymers [Ag(bpp)]n counterbalanced by the organic anions. However, in 2 the bda anions participate in metal coordination connecting the polymers in pair. It is worth of note that six and four crystallographic independent Ag(bpp) units are present in the unit cell of 1 and 2, respectively, a feature likely affected by the conformational freedom of bpp ligands, although experimental conditions, solvent and packing effect cannot be ruled out. In both the compounds the crystal packing shows an extensive network of H‐bonds realized by the numerous water molecules and the anionic organic species. The band gap energies of 1 and 2 were calculated in order to explain their activity towards the degradation of toxic methylene blue dye, and compound 1 was found to be more efficient for this purpose.

A 1D silver(I) coordination polymer of a new hydrozone-hydrazide ligand: Spectral, structural, emission, and anti-bacterial properties and its application as a solid source precursor for silver oxide nanoparticles

A new one-dimensional (1D) coordination polymer of composition [Ag(L)(NO3)]n was synthesized by a reaction of silver(I) nitrate with a new hydrazone-hydrazide ligand (L) derived from 2-acetyl furan and ethyl hydrazine carboxylate. Both the ligand, L, and the silver(I) complex were characterized using elemental analysis, electron impact mass spectrometry (EI-Mass), infrared (IR), proton nuclear magnetic resonance (1H NMR), ultraviolet–visible (UV–Vis) spectroscopy, and emission spectroscopy analyses. Single-crystal X-ray diffraction study shows that the structure of the silver(I) complex consists of 1D polymeric chains in which silver(I) ion is in four coordination complexes arising from one N, O-chelating L and two O, O′-bridging nitrate anions. The complex emitted energy around 360 nm and was used as a single precursor for synthesis of silver oxide nanoparticles (Ag2O NPs). From transmission electron microscopy (TEM) and higher-resolution TEM (HR-TEM) images, the as-prepared Ag2O NPs were nearly spherical in shape with average particle sizes of approximately 22–24 nm. Anti-bacterial properties of both the ligand and the metal complex were studied.

Synthesis, Crystal Structure, and Luminescence of Cadmium(II) and Silver(I) Coordination Polymers Based on 1,3-Bis(1,2,4-triazol-1-yl)adamantane.

Coordination polymers with a new rigid ligand 1,3-bis(1,2,4-triazol-1-yl)adamantane (L) were prepared by its reaction with cadmium(II) or silver(I) nitrates. Crystal structure of the coordination polymers was determined using single-crystal X-ray diffraction analysis. Silver formed two-dimensional coordination polymer [Ag(L)NO3]n, in which metal ions are linked by 1,3-bis(1,2,4-triazol-1-yl)adamantane ligands, coordinated by nitrogen atoms at positions 2 and 4 of 1,2,4-triazole rings. Layers of the coordination polymer consist of rare 18- and 30-membered {Ag2L2} and {Ag4L4} metallocycles. Cadmium(II) nitrate formed two kinds of one-dimensional coordination polymers depending on the metal-to-ligand ratio used in the synthesis. Coordination polymer [Cd(L)2(NO3)2]n was obtained in case of a 1:2 M:L ratio, while for M:L = 2:1 product {[Cd(L)(NO3)2(CH3OH)]·0.5CH3OH}n was isolated. All coordination polymers demonstrated ligand-centered emission near 450 nm upon excitation at 370 nm.

Polymorphism and structural characterization of a silver(I) coordination polymer: an inorganic polymer co-former in the preparation of curcumin-containing co-crystals

Polymorphism and structural characterization of a silver(I) coordination polymer: an inorganic polymer co-former in the preparation of curcumin-containing co-crystals

A new silver coordination polymer based on 4,6-diamino-2-pyrimidinethiol: synthesis, characterization and catalytic application in asymmetric Hantzsch synthesis of polyhydroquinolines

A highly efficient and stable heterogeneous coordination polymer (CP) was successfully prepared by hydrothermal combination of silver and 4,6-diamino-2-pyrimidinethiol. The prepared coordination polymer was characterized by FT-IR, XRD, TGA, SEM, EDX, X-ray mapping and Nitrogen adsorption–desorption analysis. The prepared Ag–CP exhibit excellent catalytic activity in multicomponent Hantzsch synthesis of polyhydroquinolines under mild reaction conditions in relatively short reaction times. The heterogeneity of the catalyst was confirmed by the hot filtration test; also, the catalyst was reused for at least four times under the optimized reaction conditions without any significant loss of its catalytic activity.

A sky-blue luminescent silver(I) complex with a one-dimensional zipper-like structure constructed with 2-diphenylphosphinopyridine and thiocyanate

In this work, the synthesis, characterization, and phosphorescent properties of the coordination polymer, {Ag3(dppy)2[μ-SCN]3}n (1), are described. X-ray crystallography showed that the complex forms a one-dimensional infinite zipper-like chained structure linked by thiocyanate as the bridging ligand. The silver(I) complex exhibits a strong sky-blue phosphorescence with a high quantum yield of 70.2% in the solid state at ambient temperature. Additionally, following a temperature change from 418 to 77 K, the complex displays a remarkable luminescent thermochromic property. A novel 1D zipper-like silver(I) coordination polymer is constructed by 2-diphenylphosphinopyridine and thiocyanate. It exhibits strong sky-blue phosphorescence with high quantum yield of 70.2% in solid state at ambient temperature. Furthermore, its reversible thermochromism is demonstrated.

Three Silver(I) Coordination Polymers Based on Pyridyl Ligands and Auxiliary Carboxylic Ligands: Luminescence and Efficient Sensing Properties.

Easily producible sensors for harmful industrial waste compounds are of significant interest for both human health and the environment. Three novel coordination polymers, [Ag(μ-aca)(μ4-bztpy)1/2] (1), [Ag(μ-bza)(μ-bpa)] (2), and [Ag2(μ-aca)2(μ-bpa)2]·EtOH·2H2O (3), were assembled in this study by reactions using Ag+ as a node with the pyridyl ligand 1,2,4,5-tetrakis(4-pyridyl)benzene (bztpy) or 9,10-bis(4-pyridyl)anthracene (bpa) and an auxiliary chelating carboxylic ligand. Single-crystal X-ray structural analyses revealed that compound 1 has a 3D framework consisting of 1D [Ag(aca)]∞ chains and bztpy linkers, while 2 and 3 have 2D layered structures consisting of binuclear Ag-carboxylate units and bpa linkers, respectively. Topological studies revealed that 1 has a bbf topology, while 2 and 3 are 2D [4,4] rhombic grids. The compounds were further characterized by powder X-ray diffraction, IR, elemental analysis, thermogravimetric analysis, and a luminescence study. The solids of 1-3 exhibited intense photoluminescent emission with λemmax at ca. 493, 472, and 500 nm, respectively. Remarkably, due to their excellent framework stability, 1 and 2 can act as multiresponsive luminescent sensors for nitrobenzene, Fe3+, and Cr2O72- with a high selectivity and sensitivity ascribed to their quenching effect.

Multi-dimensional copper(I) and silver (I) coordination polymers assembled with a pyridyl bis-urea macrocyclic ligand

We report the synthesis of a new flexible multimodal macrocyclic ligand, protected pyridyl bis-urea macrocycle 1, and two of its coordination polymers Cu2I2(1)2·(CH3CN)1.63 (2) and [Ag(1)](NO3).(H2O)2.49 (3). The ligand possesses conformational flexibility and adopts different conformations and binding modes depending on the metal ions. The crystal structure of 2 shows a 2D coordination network constructed from rhomboidal Cu2I2 dimer units and 1 as a bridging ligand binding through the pyridyl N atoms. 3 forms a sophisticated 3D structure with 1D chains formed by N-Ag-N links between pyridyl N atoms of two adjacent macrocyclic ligands and Ag(I) ions. These chains form 2D layers through longer Ag-O interactions and the chains are linked together into a 3D network by hydrogen bonding involving interstitial water molecules. These results indicate the potential of ligand 1 in the self-assembly of coordination polymers with diverse topology and functional applications.

Two 1D double-chain silver coordination polymers constructed by Ag-Ag bonds: Synthesis, structure and properties

Two new one-dimensional (1D) double-chain Ag(I) coordination polymers, namely: {[Ag(Hcn)(bpy)]·2CH3OH}n (1), [Ag2(Hidc)(H2O)2]n (2) (Hcn = 2-hydroxycinnamate, bpy = 4,4′-bipyridine, Hidc = 4,5-imidazoledicarboxylate), were synthesized by volatilization method and characterized by single-crystal X-ray diffraction, elemental analysis, IR and UV–vis spectra. Single-crystal analyses show that although two Ag(I) CPs are both 1D double-chain structure constructed by Ag-Ag bonds, CP 1 is linear, while CP 2 is zigzagged. This difference in the structure may be due to the symmetry of the repeat unit of the Ag(I) CPs and the linkage pattern of the Ag-Ag bonds, in which the repeat unit of CP 1 is symmetric, whereas that of CP 2 is asymmetric. The fluorescence properties of the ligands and CPs 1-2 in the solid-state were studied. The fluorescence peaks of the two Ag(I) CPs were weakened compared to the ligands, which is attributed to ligand-centered fluorescence. The partial quenching of the aggregates may be due to the Ag-Ag interactions. In addition, cyclic voltammograms of CPs 1-2 indicated an irreversible Ag+/Ag couple with the order of reversibility being 1 > 2.

Silver(I) Coordination Polymers Immobilized into Biopolymer Films for Antimicrobial Applications

This study describes a template-mediated self-assembly synthesis, full characterization, and structural features of two new silver-based bioactive coordination polymers (CPs) and their immobilization into acrylated epoxidized soybean oil (ESOA) biopolymer films for antimicrobial applications. The 3D silver(I) CPs [Ag4(μ8-H2pma)2]n·4nH2O (1) and [Ag5(μ6-H0.5tma)2(H2O)4]n·2nH2O (2) were generated from AgNO3 and pyromellitic (H4pma) or trimesic (H3tma) acid, also using N,N'-dimethylethanolamine (Hdmea) as a template. Both 1 and 2 feature the intricate 3D layer-pillared structures driven by distinct polycarboxylate blocks. Topological analysis revealed binodal nets with the flu and tcj/hc topology in 1 and 2, respectively. These CPs were used for fabricating new hybrid materials, namely, by doping the [ESOA]n biopolymer films with very low amounts of 1 and 2 (0.05, 0.1, and 0.5%). Their antimicrobial activity and ability to impair bacterial biofilm formation were investigated in detail against both Gram-positive (Staphylococcus epidermidis and Staphylococcus aureus) and Gram-negative (Pseudomonas aeruginosa and Escherichia coli) bacteria. Both silver(I) CPs and derived biopolymer films showed activity against all the tested bacteria in a concentration-dependent manner. Compound 1 exhibited a more pronounced activity, especially in preventing biofilm growth, with mean bacterial load reductions ranging from 3.7 to 4.3 log against the four bacteria (99.99% bacterial eradication). The present work thus opens up antibiofilm applications of CP-doped biopolymers, providing new perspectives and very promising results for the design of functional biomaterials.

Anticancer Properties and Mechanisms of Singly-Protonated Dehydronorcantharidin Silver Coordination Polymer in a Bladder Cancer Model.

Bladder cancer is the most common malignant urinary system tumor. Chemotherapy is frequently used as a treatment regimen for patients with bladder cancer, however, new and effective drugs for bladder cancer need to be developed. The present study examined the effects and mechanisms of Ag-SP-DNC, a silver and singly-protonated dehydronorcantharidin complex, on bladder cancer in vitro and in vivo. It was identified that Ag-SP-DNC suppressed cell proliferation and induced apoptosis in bladder cancer cells in vitro, a suppression associated with G0/G1 phase arrest and elevated intracellular reactive oxygen species (ROS) levels. Furthermore, Ag-SP-DNC enhanced the cleaved caspase-3 levels, disrupted the mitochondrial transmembrane potential balance, and induced intracellular calcium overload. The Ag-SP-DNC-induced bladder cancer cell apoptosis was significantly decreased following treatment with a broad caspase inhibitor, zVAD-fmk. In addition, treatment of MB49 tumor-bearing mice with Ag-SP-DNC significantly inhibited tumor growth and decreased the anti-apoptosis and cell cycle promotion protein levels in the tumor. The results of the present study suggested that Ag-SP-DNC elicits a strong anticancer effect against bladder cancer, and can therefore be used as a promising treatment for bladder cancer.