Ag Coordination Polymers Research Articles

Two one-dimensional silver(I) coordination polymer modified electrodes for hydrogen evolution reaction and H2O2 recognition

Two new Ag(I) coordination polymers (CPs), namely: [Ag4(m-MOPhHIDC)2(BBM)2]n (1) {[Ag(BBM)](NO3)}n (2) (m-MOPhHIDC = m-methoxyanisaldehyde imidazole dicarboxylate, BBM = 2,2-(1,4-butanediyl)bis-1,3-benzimidazole), have been synthesized by solvothermal method and characterized. Structural analyses show that both complexes are one-dimensional chain coordination polymers, but the one-dimensional chains have different shapes, in which CP-1 is "V" shaped, and CP-2 is "wave-shaped". The electrochemical properties of composite electrodes CE-1 and CE-2 formed by mixing two coordination polymers with carbon paste electrodes were investigated respectively. Electrocatalytic hydrogen evolution characteristics of two composite electrodes were investigated by linear scanning voltammetry (LSV) in 0.5 M H2SO4 electrolyte, at 298 K the results show that when the current density reaches 10 mA cm−2, their overpotential positively shifted by 284 and 289 mV compared to CE (905 mV). And the Tafel slope of the CE-1 and CE-2 was 162 and 164 mV dec−1, respectively. The CE-1 exhibited superior electrocatalytic ability than CE-2, which may be attributed to the different coordination modes of central silver ions in the two CPs. In addition, the composite electrodes CE-1 and CE-2 also have a good identification effect on H2O2, and the detection limits of 36.7 and 6.2 μM in the linear range of 0.5-4000 μM were determined by chronoamperometry. Results show that the Ag(I) CPs can be used as effective dualfunctional electrocatalysts.

Luminescent and sustainable d10 coinage metal thiolate coordination polymers for high-temperature optical sensing

The d10 coinage metal coordination polymers (CPs) are known to display photophysical properties which can be tuned depending on the functionality of the ligand. Three new CPs made of d10 coinage metals and methyl thiosalicylate, [M(o-SPhCO2Me)]n (M= Cu, Ag, Au), are reported. They are all constructed from one-dimensional metal-sulfur networks, in which Cu and Ag are three-coordinated to sulfur atoms, whereas Au is only two-coordinated. It results that both Cu(I) and Ag(I) CPs show orange photoemission at room temperature, and the Au(I) one exhibits near-infrared emission at low temperatures. The intense orange-emissive Ag(I) CP and the blue-emissive coumarin 120 have been mixed in an organic matrix, the polyvinylidene fluoride (PVDF), to form a dual luminescent flexible composite film. This film, evaluated for thermometry, shows great sensitivity for temperatures up to 100°C, a temperature never reached with non-lanthanide-based CPs.

Aggregated coordination polymers of Ag+ with a cysteine derivative ligand containing an AIEgen.

We investigated coordination polymers of Ag+ with a cysteine-based thiol ligand designed to contain a tetraphenylethylene AIEgen (L- and D-1). The coordination polymers, forming in a variety of protic and aprotic organic solvents, such as THF, CH3CN and CH3OH, were shown to undergo aggregation in H2O/THF binary solvents at water volume fractions above 50%, where emission was substantially enhanced while the CD profile was reversed, yet the dependence of the CD signal on ee remained S-shaped for the polymers in the aprotic organic solvents THF and CH3CN, in contrast to that in protic solvents CH3OH and C2H5OH.

Facile synthesis of two novel micro Ag-Cyanamide derivatives and different approach of 4-CyBA preparation, characterization and in vitro evaluations (anti-bacterial and toxicity properties)

4-CyBA (4-Cyanamide Benzoic Acid) and two novel Ag-coordination polymers of 4-CyBA; Ag-A-4-CyBA and Ag-4-CyBA have been synthesized. In the current work, 4-CyBA was prepared throughout a different methodology in comparison with the other ways which previously had been applied to synthesize this organic material. The nature and structural effects of 4-CyBA, Ag-A-4-CyBA and Ag-4-CyBA were studied with regard to the physical and biological features of them. Ag-4-CyBA has baculiform, and Ag-A-4-CyBA has prickle-on-spike form and the surface areas of them were found 4.779 m2/g and 30.851 m2/g, respectively. The antibacterial and toxicity activities of these materials were moreover assessed. The results exhibited that Ag-A-4-CyBA displayed the best antibacterial activity special against Gram-positive type (S. aureus) even more than reference drug tetracycline. Furthermore, the toxic potencies of these materials were in the order of Ag-A-4-CyBA > 4-CyBA > Ag-4-CyBA against HT29 and A549 cancerous cell-lines, but for AGS, the sequences of toxicity were 4-CyBA > Ag-4-CyBA > Ag-A-4-CyBA as the results of MTT-tests. Again, Ag-A-4-CyBA has the most toxic activity against HT-29 and A549 carcinomatous cell lines among these three compound.

Chiral Recognition by Flexible Coordination Polymers of Ag+ with a Cysteine-Based Chiral Thiol Ligand That Bears a Binding Site.

We report a new scheme for chiral recognition using coordination polymers of Ag+ with a chiral thiol ligand that contains a binding group. N-Benzoyl-l-cysteine ethyl ester equipped with a boronic acid group at the para position of the phenyl ring forms coordination polymers with Ag+ in alkaline aqueous solutions that exhibit excellent selectivity toward a d-glucose enantiomer over l-glucose, while the coordination polymers from the d-cysteine-based thiol ligand are specific for l-glucose. It is assumed that a conformation change occurs upon interaction of a saccharide molecule with the polymeric chain receptor, for which the next binding is promoted, leading to the highly effective chiral recognition, despite the flexible nature of the polymeric receptor.

Nanospheres from coordination polymers of Ag+ with a highly hydrophilic thiol ligand formed in situ from dynamic covalent binding and a hydrophobic thiol

A supramolecular nanosphere with a diameter of 8.7 nm is obtained in an aqueous alkaline solution via glucose binding to a boronic acid-based thiol (4-MPBA) as a hydrophilic ligand, together with a hydrophobic thiol ligand n-C8H17SH.

Nanosphere [Ag(SR)]n: coordination polymers of Ag+ with a combination of hydrophilic and hydrophobic thiols.

We propose to create nanospheres in aqueous solutions from coordination polymers of Ag+ with a combination of a hydrophilic and a hydrophobic thiol, of diameter ca. 2.7 nm in the case of using cysteine and n-butanethiol. A spectral probe for the formation of the nanospheres is a reversal of the CD signal at 253 nm from negative in the case of cysteine alone to positive when cysteine and n-BuSH are both employed, together with an amplification.

Coordination polymers of Ag(i) and Hg(i) ions with 2,2′-azobispyridine: synthesis, characterization and enhancement of conductivity in the presence of Cu(ii) ions

The cationic coordination polymers (CPs) of the types [Hg2(abpy)2]n[PF6]2n (1) and [Ag(abpy)]n[PF6]n (2) (abpy = 2,2'-azobispyridine) were synthesized and characterized. Experimentation using the crystals confirmed that 1 and 2 are conductors of electricity. The relative conductivity of 1 is 62 times greater than that of 2. The conductivity of 1 increases 70 fold when it reacts with Cu2+ ions.

Helical nanofibers of N-(perfluorooctanoyl)cysteine ethyl ester in coordination polymers of Ag.

We propose using the formation of coordination polymers of Ag+ to probe differences between the perfluorinated alkyl chain and the alkyl chain by deriving a thiol ligand, N-(perfluoroalkanoyl)cysteine. Rapid formation in EtOH of P-/M-helical nanofibrils of high thermostability was found for N-(perfluorooctanoyl)-l-/d-cysteine ethyl esters at the μM level upon mixing with Ag+, but not for the octanoyl counterpart. This difference was also observed in terms of circular dichroism-enantiomeric excess dependence.

Supramolecular chirality of coordination polymers of Ag+ with a chiral thiol ligand that bears a β-turn structure.

We report coordination polymers forming from Ag+ and a chiral thiol ligand that bears a β-turn structure, exhibiting supramolecular chirality showing both the majority rules effect (MRE) and the racemate rules effect (RRE).

A Rare Heterobimetallic Ca–Ag Coordination Polymer as Sensitive Luminescence Sensor for TNP

The present work reports the synthesis, characterization, and crystal structure of a rare 2-D heterobimetallic Ca–Ag coordination polymer (CP) [Ca(DMF)4Ag2(SCN)4]n (1) (DMF = N,N-dimethylformamide). 1 is constructed by Ca metallic atoms, Ag2 dinuclear cluster, and SCN− bridges. This Ca–Ag CP exhibits strong luminescence property in its DMF suspension, and has been exploited as a highly sensitive sensor for the detection of TNP. Moreover, the energy-transfer mechanism of 1 for sensing TNP had been preliminarily elucidated.

Heterobimetallic Mg–Ag coordination polymer with luminescence and 2,4,6-Trinitrophenol sensing properties

The first SCN-bridged Mg–Ag coordination polymer, namely [Mg(DMF)4Ag2(SCN)4]n (1) (DMF = N,N-dimethylformamide) has been synthesized and structurally characterized by FT-IR spectroscopy, elemental analysis and single crystal X-ray diffractions. X-ray structural analysis reveals that 1 displays a two-dimensional (2-D) framework, which contains Mg metallic atoms, Ag2 dimeric units, and SCN− bridges with two kinds of connected manners. This Mg–Ag coordination polymer exhibits strong luminescence property and can act as highly sensitive sensor for 2,4,6-Trinitrophenol in both DMF and aqueous media. Moreover, the mechanism of 1 for highly sensitive detection of TNP had been preliminarily studied.

Ultrasonic green synthesis of an Ag/CP nanocomposite for enhanced photodegradation effectiveness

A nanoparticle of cobalt(II) coordination polymer (CP), [Co(L)(npht)]n (1) (H2npht=4-nitrophthalic acid, L=1,3-bis(5,6-dimethylbenzimidazol-1-ylmethyl)benzene) and its nanocomposite (Ag/CP 1) were obtained by the sonochemical approach and characterized by IR, elemental analysis, thermogravimetric analyses (TGA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and X-ray powder diffraction (XRPD). CP 1 shows a 1D double chain containing two different helical chains, which is further extended into a two-dimensional supramolecular framework by C–H⋯O hydrogen bonding interactions. The photoluminescence properties and photocatalytic properties of the nanoparticles of CP 1 and Ag/CP 1 on the degradation of methylene blue (MB) were investigated, Ag/CP 1 exhibited excellent photocatalytic activity under UV and visible light, which can be attributed to the strong interactions between Ag nanorods and CP 1, which lead to electron–hole pair separation between Ag nanorods and CP 1. In addition, the photocatalytic mechanism is also carried out by introducing t-butyl alcohol (TBA) as a widely used ·OH scavenger. The influence of ultrasound irradiation time and power on the morphology and size of the nanostructure CP 1 were studied. The results indicated that a decrease in time and an increase in power led to a decrease of particle size.

Two-Dimensional Coordination Polymers with “X”-Shaped Cavities as Adsorbents of Oxoanion Pollutants and Toxic Dyes

The role of cationic and neutral two-dimensional (2D) coordination polymers (CPs) in the efficient capture of inorganic pollutants (chromate and dichromate) and toxic dyes has been explored. Two cationic CPs with Ag(I) salts of BF4– and ClO4– anions and one neutral CP with Cd(NO3)2 of bis(pyridylcarboxamide) ligands have been structurally characterized, and it was found that all of them have isostructural 2D CPs. The sorption of chromate/dichromate by CPs via anion exchange mechanism was shown to depend not only on the nature of the network but also on the nature of the anion present in the as-synthesized host. Among three CPs, the BF4– containing Ag(I) CP exhibited a better ability of sorbing chromate and dichromate from very dilute solution of sorbates (10–4 M). On the other hand, neutral Cd(II) CP containing NO3– ion were found to have a better ability to sorb chromate/dichromate from somewhat concentrated (10–1 M) solutions. Further, BF4– and NO3– containing CPs exhibit selective sorption of chromate ...

Sonochemical synthesis of two nanostructured silver(I) coordination polymers based on semi-rigid bis(benzimidazole) ligands

Nanoparticles of two silver(I) coordination polymers (CPs), [Ag2(L1)2(DCTP)]n (1) and [Ag2(L2)(DCTP)]n (2) (L1=1,3-bis(5,6-dimethylbenzimidazol-1-ylmethyl)benzene, L2=1,4-bis(benzimidazol-1-yl)-2-butene, H2DCTP=2,5-dichloroterephthalic acid), were synthesized by the sonochemical approach and hydrothermal method. Both CPs were characterized by elemental analysis, IR spectra, single-crystal X-ray diffraction, scanning electron microscopy (SEM), and thermogravimetric analyses (TGA). CP 1 exhibits a 2D 4-connected sql net with the point symbol {44.62}. While CP 2 displays a 2D 3,4-connected 3,4L13 net with the point symbol {4.62}2{42.62.82}. The structural diversity indicates that semi-rigid bis(benzimidazole) co-ligands play important roles in tuning the structures of the mixed Ag(I) CPs. The ultrasound irradiation time, temperature, and power showed significant effects on the morphology and growth process of the nanoparticles of two silver(I) CPs. The luminescence and photocatalytic properties of the nanoparticles of CPs 1–2 on the degradation of methyl blue (MB) were also investigated in detail.

Influence of anions and solvent molecules on the packing and emission spectra of coordination polymers based on silver ions and an anthracene derivative

The structure-property relationships in Ag-coordination polymers with an anthracene-derived ligand are studied.

Synthesis and structures of ligand-dominated one-dimensional silver(I)–bis(pyridylmethyl)amine coordination chains

Reactants slow diffusion of Ag(I) salts with 3,4′-bis(pyridylmethyl)amine (3,4′-bpma), an unsymmetric bis-pyridyl ligand equipped with a non-innocent amine backbone, afforded polymeric coordination adducts 1–5 having a general formula {[Ag(3,4′-bpma)(solv)]X}n (solv = H2O, CH3OH, and none; X= CF3CO2–, BF4–, ClO4–, CF3SO3–, and SbF6–). Single-crystal X-ray diffraction (SCXRD) analyses reveal that colorless crystals of Ag(I) coordination polymers (CPs) 1–5 have very similar one-dimensional (1D) non-flat chain structures, which are preferentially depicted as a “zipper-like” rather than a ladder-like or a double-stranded chain topologies. The 3,4′-bpma ligand in these Ag(I) CPs displays a μ3-bridging mode with a gauche–trans (1,4, and 5) and a trans–trans (2 and 3) conformations. Noteworthy, anions do not show strong influence on structural modulation of Ag(I) CPs in the solid state, but really affect CP conformations and packing fashions, indicative of a ligand-dominated assembly process for such a Ag(I)–3,4′-bpma system. Thermal stabilities and solid-state photoluminescence properties of crystalline materials 1–5 were investigated.

Synthesis, structure, and luminescence property of a series of Ag–Ln coordination polymers with the N-heterocyclic carboxylato ligand

Six Ln–Ag coordination polymers {[LnAg2(IN)4(H2O)5]·NO3·2H2O}n (Ln=Ho (1) and Tb (2), HIN=isonicotinic acid), {[PrAg2(IN)4(H2O)2]·NO3·H2O}n (3), [LnAg(pdc)2]n (Ln=Eu(4) and Pr (5), H2pdc=3,4-pyridine-dicarboxylic acid) and [NdAg(bidc)2(H2O)4]n (6) (H2bidc=benzimidazole-5,6-dicarboxylic acid) have been hydrothermally synthesized and characterized by single crystal X-ray diffraction, elemental analysis, IR, UV–vis-NIR absorption spectra, fluorescence spectra and thermogravimetric analysis. Structural analyses reveal that the six polymers exhibit 0D (polymer (1)), 1D (polymer (2)), 2D (polymers (3) and (5)) and 3D (polymers (4) and (6)) infinite structures, respectively. Polymers (1)–(6) exhibit the Ln(III) characteristic emission in the near-infrared (NIR) region or in the visible region. Especially, the NIR emission bands of polymers 1, 5 and 6 evidently present shift or splitting due to formation of the Ln–Ag coordination polymers. This can be attributed to the tune of inner levels in Ln–Ag system caused by the interact and influence between the 4d orbital of the Ag(I) ion and the 4f orbital of the Ln(III) ion, which can be confirmed by the UV–vis-NIR absorption spectra of the polymers. In addition, the distortion of coordination geometry as well as difference of the coordination number around the Ag(I) ion affect the structure framework.

Coordination polymers of Ag(I) based on iminocarbene ligands involving metal-carbon and metal-heteroatom interactions

The reaction of Ag2O with three novel imino-NHC ligands derived from 2-chloroacetophenone with pendant N-donor functional group incorporated by reaction with methoxyamine and 1-methyl/ethyl/n-butyl-substituted imidazoles afforded one-dimensional coordination polymers with [(-NHCarbene)Ag(NHCarbene-)PF6]n formulation involving both carbon-metal and heteroatom-metal interactions, the carbon and heteroatom involved in coordination to silver being from different molecule of the ligand. The complexes as well as the ligands were characterized by spectroscopic methods as well as the solid state structures determined in case of 2a, 3a and complex 5. The iminocarbene ligands serve as non-chelating building block for supramolecular silver assemblies.

Heteronuclear, mixed-metal Ag(I)-Mn(II) coordination polymers with bridging N-pyridinylisonicotinohydrazide ligands: synthesis, crystal structures, magnetic and photoluminescence properties.

Mixed-metal dicyanoargentate-bridged coordination polymers of Ag(i)-Mn(ii) have been prepared and their structure and magnetic properties were determined. Reaction of manganese(ii) chloride and potassium dicyanoargentate(i) with (X)(pyridin-2-ylmethylene)isonicotinohydrazide ligands (HL(1) X = Ph, HL(2) X = Me, HL(3) X = H) produced the coordination polymer 2D-[Mn(μ-L(1))(Cl)(μ-NCAgCN)Mn0.5(CH3OH)]n (), 1D-{[Mn(L(2))(Cl)(μ-NCAgCN)Mn0.5(CH3OH)]CH3OH}n () and [Mn(L(3))(Cl)(μ-NCAgCN)Mn0.5(CH3OH)]n () in good yields. Trinuclear {Mn(μ-L(1))Mn(μ-L(1))Mn} and [Ag(CN)2](-) building units form a two-dimensional slab in and 1D strands in . Variable temperature magnetic susceptibility measurements showed that despite the long distance among the high spin Mn(ii) ions [10.4676(12) Å and 10.522(1) Å, for and , respectively], weak antiferromagnetic coupling takes place through the long NC-Ag-CN bridge. The best fit parameters to the model led to the magnetic coupling constant of J = -0.1 and J = -0.47 cm(-1) for and , respectively. The photoluminescence behaviour of compounds and was studied. The spectrum of compound shows a broad emission centered at about 450 nm and two excitation maxima at 270 and 310 nm.