Silver-based Coordination Polymers Research Articles

Five Novel Silver-Based Coordination Polymers as Photoluminescent Sensing Platforms for the Detection of Nitrobenzene.

Nitrobenzene (NB) is a highly toxic chemical and a cause for concern to human health and the environment. Hence, it is worthwhile to design new efficient and robust sensing platform for NB. In this study, we present three newly synthesized luminescent silver cluster-based coordination polymers, {[Ag10(StBu)6(CF3COO)4(hpbt)] (DMAc)2(CH3CN)2}n (hpbt = N,N,N',N'N",N"-hexa(pyridine-4-yl)benzene-1,3,5-triamine), [Ag12(StBu)6(CF3COO)6(bpva)3]n (bpva = 9,10-Bis(2-(pyridin-4-yl)vinyl)anthracene), and {[Ag12(StBu)6(CF3COO)6(bpb)(DMAc)2(H2O)2] (DMAc)2}n (bpb = 1,4-Bis(4-pyridyl)benzene) composed of Ag10, Ag12 and Ag12 cluster cores, respectively, connected by multidentate pyridine linkers. Besides, two new luminescent polymorphic silver(I)-based coordination polymers, [Ag(CF3COO)(dpa)]n (dpa = 9,10-di(4-pyridyl)anthracene) referred to as Agdpa (H) and Agdpa (R), where H and R denote the hexagon-like and rod-like crystal shapes, respectively, have been prepared. The coordination polymers exhibit highly sensitive luminescence quenching effect to NB, attributed to the π-π stacking interactions between the polymers and NB as well as the electron-withdrawing character of NB.

Silver-based coordination polymers assembled by dithioether ligands: potential antibacterial materials despite received ideas.

We report on the first examples on the antibacterial activity towards Gram-negative and Gram-positive bacteria of 2D silver-based coordination polymers obtained by self-assembly with acetylenic dithioether ligands. Their structure imparts a good stability that allows a sustainable release of Ag+ in the media.

Recent Advances of Silver-Based Coordination Polymers on Antibacterial Applications.

With the continuous evolution of bacteria and the constant use of traditional antibiotics, the emergence of drug-resistant bacteria and super viruses has attracted worldwide attention. Antimicrobial therapy has become the most popular and important research field at present. Coordination Polymer (CP) and/or metal-organic framework (MOF) platforms have the advantages of a high biocompatibility, biodegradability, and non-toxicity, have a great antibacterial potential and have been widely used in antibacterial treatment. This paper reviewed the mechanism and antibacterial effect of three typical MOFs (pure Ag-MOFs, hybrid Ag-MOFs, and Ag-containing-polymer @MOFs) in silver-based coordination polymers. At the same time, the existing shortcomings and future views are briefly discussed. The study on the antibacterial efficacy and mechanism of Ag-MOFs can provide a better basis for its clinical application and, meanwhile, open up a novel strategy for the preparation of more advanced Ag-contained materials with antibacterial characteristics.

Photocatalytic Oxidation of Sulfides on Silver-Based Coordination Polymers

Key words silver catalysis - photocatalysis - coordination polymers - oxidation - sulfides - sulfoxides

2D and 3D silver-based coordination polymers with thiomorpholine-4-carbonitrile and piperazine-1,4-dicarbonitrile: structure, intermolecular interactions, photocatalysis, and thermal behavior

The reaction of the thiomorpholine-4-carbonitrile and piperazine-1,4-dicarbonitrile ligands afforded four Ag(i) coordination polymers with excellent photocatalytic activity in the degradation of the mordant blue 9 dye.

Mechanochemical P-derivatization of 1,3,5-Triaza-7-Phosphaadamantane (PTA) and Silver-Based Coordination Polymers Obtained from the Resulting Phosphabetaines.

We have described earlier that in aqueous solutions, the reaction of 1,3,5-triaza-7-phosphaadamantane (PTA) with maleic acid yielded a phosphonium-alkanoate zwitterion. The same reaction with 2-methylmaleic acid (citraconic acid) proceeded much slower. It is reported here, that in the case of glutaconic and itaconic acids (constitutional isomers of citraconic acid), formation of the corresponding phosphabetaines requires significantly shorter reaction times. The new phosphabetaines were isolated and characterized by elemental analysis, multinuclear NMR spectroscopy and ESI-MS spectrometry. Furthermore, their molecular structures in the solid state were determined by single crystal X-ray diffraction (SC-XRD). Synthesis of the phosphabetaines from PTA and unsaturated dicarboxylic acids was also carried out mechanochemically with the use of a planetary ball mill, and the characteristics of the syntheses in solvent and under solvent-free conditions were compared. In aqueous solutions, the reaction of the new phosphabetaines with Ag(CF3SO3) yielded Ag(I)-based coordination polymers. According to the SC-XRD results, in these polymers the Ag(I)-ion coordinates to the N and O donor atoms of the ligands; however, Ag(I)-Ag(I) interactions were also identified. The Ag(I)-based coordination polymer (CP1.2) formed with the glutaconyl derivative of PTA (1) showed considerable antimicrobial activity against both Gram-negative and Gram-positive bacteria and yeast strains

Can Solventless Reactions Sometimes Succeed When Solvent-Mediated Reactions Fail? A Second Case Study for Cu(I) and Ag(I) Complexes of Divergently Bridging Diimines without or with Fluorinated Azolates

ABSTRACT This paper provides the fifth manifestation of a new tradition by which the editors of Comments on Inorganic Chemistry wish to lead by example, whereby we start publishing original research content that, nonetheless, preserves the Journal’s identity as a niche for critical discussion of contemporary literature in inorganic chemistry (For the previous manifestations, see: Comments Inorg. Chem. 2018, 38, 1–35; 2019, 39, 1–26; 2019, 39, 188–215; 2020, 40, 1–24.) Herein, synthetic details, solid-state structures, and photophysical properties of a group of silver(I) and copper(I) complexes are described. Two silver-based coordination polymers have been obtained: {[3,5-(CF3)2Pz]2(bpp)Ag2}∞ (1) and {[3,5-(CF3)2Pz][5-(C6F5)Ttz](bpp)Ag}∞ (2) – constructed from bent 1,3-bis(4-pyridyl)propane (bpp), 3,5-bis(trifluoromethyl)pyrazole ([3,5-(CF3)2Pz]H) and 5-pentafluorophenyl-tetrazole ([5-(C6F5)Ttz]H) in order to inspect the influence of mixed ligands on the resulting silver-based coordination complexes. The structure of 1 shows a distorted trigonal planar geometry with both the bpp and [3,5-(CF3)2Pz] ligands binding to the silver atom. The silver in 2 shows an uncommon interaction with the three different ligands. Also, two different geometries including distorted tetrahedral and distorted trigonal were presented for two different silver atoms. An interesting result was obtained for the Cu(I) coordination polymer {[Cu(bpp)2][BF4]}∞ (3) which was successfully synthesized in a solventless reaction but not a solvent-mediated reaction, hence manifesting a “green” chemistry route. The structure of 3 shows an ideal tetrahedral geometry similar to that for the silver analogue, {[Ag(bpp)2][BF4]}∞ (3a), published previously, whereas herein we obtained the same product with the same crystal structure via a more facile conventional synthetic route. All four complexes show bpp ligand-centered green emissions at ambient and cryogenic temperatures. Finally, a commentary is added to contrast the solventless vs solvent-mediated reactions in both this investigation and a precedent thereof by the same corresponding author’s group (Inorg. Chem. 2018, 57, 9962–9976), whereby reactions proceeded successfully only via the solventless route through mechanical grinding herein and spontaneous sublimation by vapor diffusion from the solid-state of one reactant to another yet nonvolatile reactant in the literature precedent, respectively.

Two silver-based coordination polymers constructed from organic carboxylate acids and 4, 4′-bipyridine-like bidentate ligands: Synthesis, structure, and antimicrobial performances

Two silver-based coordination polymers, [Ag2(O-IPA)(H2O)]·(H3O) (CP1) and [Ag2(bpe)2(Cl)2] (CP2), were facilely synthesized from AgNO3 and 5-hydroxyisophthalic acid (HO-H2IPA)/1,1′-(1,4-phenylene-bis(methylene))-bis(pyridine-3-carboxylic acid) (1pbb3ca) and 1,2-di(4-pyridyl)ethylene (bpe) by the slow evaporation method at room temperature. These two coordination polymers exhibited excellent and long-term antibacterial properties toward Gram-negative bacteria named Escherichia coli (E. coli), in which CP1 achieved the lowest minimum inhibitory concentration (MIC) of 5 ppm and largest inhibition zone of 11.12 mm due to its fastest Ag+ release rate and highest equilibrium concentration. These coordination polymers could destroy the membrane of the bacteria, leading to the death of cells. The stable and slow release of Ag+ ions in aqueous solutions for 5 d ensure the potentially further application in the purification of polluted water or medical purpose.

1D and 2D Silver-Based Coordination Polymers with Thiomorpholine-4-carbonitrile and Aromatic Polyoxoacids as Coligands: Structure, Photocatalysis, Photoluminescence, and TD-DFT Study

Four silver-based coordination polymers, {[Ag(L)2](BF4)}∞ (1), {[Ag(H2BTC)(L)]·(H3BTC)}∞ (2), {[Ag2(H2BTEC)(L)2]·3.33H2O}∞ (3), and [Ag(H25SSA)(L)]∞ (4), were synthesized using thiomorpholine-4-carbonitrile (L) as the primary ligand and three aromatic polyoxoacids as coligands: trimesic (H3BTC), pyromellitic (H4BTEC), and 5-sulfosalicylic acid (H35SSA). Compounds 1 and 3 are two-dimensional, while 2 and 4 are one-dimensional. L acts as a bis-monodentate ligand, while the Ag(I) ion is three-coordinated in 2 and four-coordinated in all of the other compounds. The tetrahedral coordination of Ag(I) in 3 leads to an almost complete absence of intermolecular interactions with the metal center. All compounds show reasonable photocatalytic activity for photocatalytic degradation of mordant blue 9 dye, with reaction rates in the 0.036-0.056 min-1 range. Changes in the reaction rates can be correlated with the type and coordination of the coligand. Complex 3 exhibits photoluminescence at 77 K, while 4 exhibits photoluminescence at both room temperature and 77 K. Luminescence lifetimes indicate electronic transitions of singlet parentage, where transitions are allowed. A TD-DFT study determined the contributions of individual singlet-singlet electronic excitations to the fluorescence, indicating that metal-intraligand transitions are responsible for luminescence in both complexes.

Synthesis, structural characterization, antibacterial activity and selective dye adsorption of silver (I)-based coordination polymers by tuning spacer length and binding mode of chromate anion

Two silver-based coordination polymers, {[AgL4]2[CrO4]}n (1) and {[Ag2(L3)(CrO4)]·CH3OH}n (2) (L4 ​= ​1,1′-(butane-1,4-diyl) bis(3-methylimidazoline-2-thione) and L3 ​= ​1,1′-(propane-1,3-diyl)bis(3-methylimidazoline-2-thione)) have been successfully prepared and fully characterized via single crystal X-ray diffraction, powder X-ray diffraction (PXRD), FT-IR spectra, elemental analysis (CHN) and thermo gravimetric analysis (TGA). Polymers 1 and 2 present different structures due to the flexiblity of the thione ligands L4 and L3 in directing the coordination mode of chramate and hence dimension of the considered polymers. The flexiblity of the ligands have no effect on the coordination geometry around the silver atoms. In contrast to the 3D CP-1, in polymer 2 hydrogen bonding interactions between the oxygen atoms of CrO42− anions and hydrogen atoms of the methylene groups of the spacer of the ligand forming a 3D supramolecular network. These compounds be able to absorbed Aniline blue (AB) as anionic dye from aqueous solution with a maximum adsorption capacity of 227.73 and 219.95 ​mg ​g−1 for 1 and 2, respectively. Therefore,polymer 1 has a slightly more efficiently than polymer 2. Three adsorption kinetic and isotherm models were investigated. The synthesized polymers possess antibacterial activity against the selected strain of Gram-negative and Gram-positive bacteria.

Selective adsorption activities toward organic dyes and antibacterial performance of silver-based coordination polymers

Two silver-based coordination polymers, [Ag2(bpy)2(cbda)] (BUC-51) and [Ag3(bpy)3(cpda)]·(NO3)·9H2O (BUC-52), have been successfully prepared by slow evaporation at room temperature. These coordination polymers exhibited good adsorptive performances toward series organic dyes with sulfonic groups, which could be ascribed to the AgcdotsO interaction between the silver(I) atoms in CPs and the oxygen atoms from sulfonic groups attached to organic dyes. Both BUC-51 and BUC-52 favoured slow release of Ag+ ions resulting into outstanding long-term antibacterial abilities toward Gram-negative bacteria, Escherichia coli (E. coli), which was tested by a minimal inhibition concentration (MIC) benchmark and an inhibition zone testing method. Both scanning electron microscope (SEM) and transmission electron microscope (TEM) images demonstrated that these two Ag-based coordination polymers could destroy the bacterial membrane and further cause death. Additionally, the excellent stability in common solvents and good optical stability under UV–visible light facilitated their adsorptive and antibacterial applications.

Structural Diversity and Argentophilic Interactions in One-Dimensional Silver-Based Coordination Polymers

A series of new one-dimensional coordination polymer materials, based on Ag(I)–N bond formation, has been synthesized and structurally characterized by single crystal X-ray diffraction. Reactions between the poly-monodentate ligands based on (1E,1′E′)-N,N′-(-bis(1-pyridin-3-yl)methanimine and Ag(I) salts give products that feature simple coordination chains or metallacyclic- and tape-based structures. For the simple chains these are as either isolated units, or assembled in dimeric and tetrameric arrangements through intermetallic, argentophilic interactions. However, crystal packing effects and solvent inclusion are found to readily disrupt this type of bonding. Density functional theory calculations provide an assessment of the bond order and the influence of anion binding on these interactions.

Investigating the effect of anion substitutions on the structure of silver-based coordination polymers

Five silver(I) compounds namely, [Ag(tdmpp)(NO3)]n (1), [Ag2(SeCN)2(tdmpp)]n (2), [Ag(tdmpp)]PF6 (3), [WS4Ag3Cl (tdmpp)1.5]·2CH3CN (4) and [WS4Ag4I2(tdmpp)]1.5CH3CN (5) were prepared by the reactions of 1,1,3,3-tetrakis(3,5-dimethyl-1-pyrazolyl)propane (tdmpp) with various silver(I) salts in order to investigate the impact of the variation of the inorganic anions on the structure of these complexes. In the chain structures of 1 and 2, each tdmpp ligand acts as a bridge between a pair of adjacent silver(I) centers. In the structure of 1, the nitrate ion act as a terminal, monodentate ligand, while in compound 2 the SeCN anion functions as bidentate-bridging ligand between two neighboring Ag(I) centers. The parallel adjacent chains in 1 and 2 are linked together by means of non-covalent interactions to generate two-dimensional structures. In contrast to the distorted AgN4O square–pyramidal structure of 1, in the structure of 2 each of the silver ions possesses a distorted tetrahedral with an AgN3Se coordination geometry. Crystals of compounds 3–5 were not suitable for X-ray diffraction studies.

Ligand effects on the structural dimensionality and antibacterial activities of silver-based coordination polymers.

Four Ag-based coordination polymers [Ag(Bim)] (1), [Ag2(NIPH)(HBim)] (2), [Ag6(4-NPTA)(Bim)4] (3) and [Ag2(3-NPTA)(bipy)0.5(H2O)] (4) (HBim = 1H-benzimidazole, bipy = 4,4'-bipyridyl, H2NIPH = 5-nitroisophthalic acid, H2NPTA = 3-/4-nitrophthalic acid) have been synthesized by hydrothermal reaction of Ag(i) salts with N-/O-donor ligands. Single-crystal X-ray diffraction indicated that these coordination polymers constructed from mononuclear or polynuclear silver building blocks exhibit three typical structure features from 1-D to 3-D frameworks. These compounds favour a slow release of Ag(+) ions leading to excellent and long-term antimicrobial activities, which is distinguished by their different topological structures, towards both Gram-negative bacteria, Escherichia coli (E. coli) and Gram-positive bacteria, Staphylococcus aureus (S. aureus). In addition, these compounds show good thermal stability and light stability under UV-vis and visible light, which are important characteristics for their further application in antibacterial agents.