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

Antiviral and Cytotoxic Activities of Ilex aquifolium Silver Queen in the Context of Chemical Profiling of Two Ilex Species

The leaves of Ilex paraguariensis (known as Yerba mate), used as a popular beverage, are a very well-recognized plant material with various biological activities, including analeptic (because of caffeine), anti-obesity (phenolics, saponins), antimicrobial, and antiviral (phenolics, saponins). Here, the chemical compositions of the leaves of two European Ilex species (× meserveae and aquifolium) with three varieties each were investigated. The terpenoid, saponin, and polyphenolic fractions were submitted for LC-MS or GC-MS analysis against a standard Mate leaf. In addition, the aroma profiles of all the species were analysed using HS-SPME-Arrow prior to GC-MS analysis. All fractions were subjected to antiviral and cytotoxic assays. We found 86 compounds in all accessions, with limonene, linalool, and p-cymene being predominant. There were minor similarities between the volatile compositions of the European and South American species. We found ursolic and oleanolic acid to be the main compounds in the terpenoid fraction. Mono-caffeoylquinic acids and di-caffeoylquinic acids were the main constituents of the polar fractions. About 180 compounds from the saponin group were tentatively identified, of which 9 and 3 were selected as distinctive markers for I. meserveae and I. aquifolium, respectively. Based on chemical screening, I. aquifolium Silver Queen was chosen as the source of terpenoid and saponin fractions and polyphenol extracts. The most substantial inhibition of cancer cell growth was observed with saponin in the case of the MCF7 (human breast cancer) cell line, while for LoVo and L929 cell lines (human colorectal cancer and reference mouse fibroblasts), it was slightly weaker. These results should be analysed further as a promising chemoprevention of colorectal and gastrointestinal cancers. Saponin and polyphenolic extracts exhibited similar activities against HSV-1 and HAdV-5, with 4-log reduction in virus titres. This study focuses our attention on a field of potential antiviral formulations derived from European holly.

Silver Coordination Polymers Driven by Adamantoid Blocks for Advanced Antiviral and Antibacterial Biomaterials

The development of sustainable biomaterials and surfaces to prevent the accumulation and proliferation of viruses and bacteria is highly demanded in healthcare areas. This study describes the assembly and full characterization of two new bioactive silver(I) coordination polymers (CPs) formulated as [Ag(aca)(μ-PTA)]n·5nH2O (1) and [Ag2(μ-ada)(μ3-PTA)2]n·4nH2O (2). These products were generated by exploiting a heteroleptic approach based on the use of two different adamantoid building blocks, namely 1,3,5-triaza-7-phosphaadamantane (PTA) and 1-adamantanecarboxylic (Haca) or 1,3-adamantanedicarboxylic (H2ada) acids, resulting in the assembly of 1D (1) and 3D (2). Antiviral, antibacterial, and antifungal properties of the obtained compounds were investigated in detail, followed by their incorporation as bioactive dopants (1 wt %) into hybrid biopolymers based on acid-hydrolyzed starch polymer (AHSP). The resulting materials, formulated as 1@AHSP and 2@AHSP, also featured (i) an exceptional antiviral activity against herpes simplex virus type 1 and human adenovirus (HAd-5) and (ii) a remarkable antibacterial activity against Gram-negative bacteria. Docking experiments, interaction with human serum albumin, mass spectrometry, and antioxidation studies provided insights into the mechanism of antimicrobial action. By reporting these new silver CPs driven by adamantoid building blocks and the derived starch-based materials, this study endows a facile approach to access biopolymers and interfaces capable of preventing and reducing the proliferation of a broad spectrum of different microorganisms, including bacteria, fungi, and viruses.

Design, Synthesis, and Anti-Cancer Evaluation of Novel Water-Soluble Copper(I) Complexes Bearing Terpyridine and PTA Ligands

This study presents a simple and energy-efficient self-assembly LAG synthetic method for novel water-soluble copper(I) complexes [Cu(terpy)(PTA)][PF6] (1) and [Cu(terpy)(PTA)2][PF6] (2). They were characterized by FT-IR, 1H, and 31P{1H} NMR spectroscopy, elemental analysis, and single-crystal/powder X-ray diffraction (for 2). The X-ray analysis of compound 2 indicates a bidentate coordination mode of terpyridine to the metal center. Variable-temperature NMR tests indicate dynamic properties for terpyridine in the case of both compounds, as well as for the PTA ligands in the case of 2. Additionally, compounds 1 and 2 exhibit interesting cytotoxic activity, which was tested on normal human dermal fibroblasts (NHDFs), human lung carcinoma (A549), human breast adenocarcinoma (MCF-7), and human cervix carcinoma (HeLa) established cell lines. In comparison to the other tested compounds, complexes 1 and 2 seem to have significantly lower IC50 values against cancer cells (A549, HeLa, MCF-7), indicating their potential as prospective anticancer agents. Moreover, both compounds show no significant toxicity towards normal skin cells (NHDFs), suggesting a certain selectivity in their action on cancer cells. Cisplatin as a reference compound also exhibited considerable cytotoxicity against cancer cells but with a low level of selectivity, which could lead to unwanted effects on normal cells. Remarkably, compounds 1 and 2 exhibit up to 30 times the cytotoxic activity of cisplatin, with a six-fold lower toxicity to normal cells. They also interact strongly with human serum albumin, suggesting potential therapeutic applications. Overall, these compounds hold significant promise as potential chemotherapeutic agents.

Coordination Polymers Constructed from an Adaptable Pyridine-Dicarboxylic Acid Linker: Assembly, Diversity of Structures, and Catalysis

4,4'-(Pyridine-3,5-diyl)dibenzoic acid (H₂pdba) was explored as an adaptable linker for assembling a diversity of new manganese(II), cobalt(II/III), nickel(II), and copper(II) coordination polymers (CPs): [Mn(μ₄-pdba)(H₂O)]_n (1), {[M(μ₃-pdba)(phen)]·2H₂O}_n (M = Co (2), Ni (3)), {[Cu₂(μ₃-pdba)₂(bipy)]·2H₂O}_n (4), {[Co(μ₃-pdba)(bipy)]·2H₂O}_n (5), [Co₂(μ₃-pdba)(μ-Hbiim)₂(Hbiim)]_n (6), and [M(μ₄-pdba)(py)]_n (M = Co (7), Ni (8)). The CPs were hydrothermally synthesized using metal(II) chloride precursors, H₂pdba, and different coligands functioning as crystallization mediators (phen: 1,10-phenanthroline; bipy: 2,2'-bipyridine, H₂biim: 2,2'-biimidazole; py: pyridine). Structural networks of 1-8 range from two-dimensional (2D) metal-organic layers (1-3, 5-8) to three-dimensional (3D) metal-organic framework (MOF) (4) and disclose several types of topologies: sql (in 1), hcb (in 2, 3, 5), tfk (in 4), 3,5L66 (in 6), and SP 2-periodic net (6,3)Ia (in 7, 8). Apart from the characterization by standard methods, catalytic potential of the obtained CPs was also screened in the Knoevenagel condensation of benzaldehyde with propanedinitrile to give 2-benzylidenemalononitrile (model reaction). Several reaction parameters were optimized, and the substrate scope was explored, revealing the best catalytic performance for a 3D MOF 4. This catalyst is recyclable and can lead to substituted dinitrile products in up to 99% product yields. The present study widens the use of H₂pdba as a still poorly studied linker toward designing novel functional coordination polymers.

Therapeutic Potential of a Water-Soluble Silver-Diclofenac Coordination Polymer on 3D Pancreatic Cancer Spheroids

This work describes the traditional wet and green synthetic approaches, structural features, and extensive bioactivity study for a new coordination polymer [Ag(μ-PTA)(Df)(H₂O)]_n·3nH₂O (1) that bears a silver(I) center, a 1,3,5-triaza-phosphaadamantane (PTA) linker, and a nonsteroidal anti-inflammatory drug, diclofenac (Df^-). Compared to cisplatin, compound 1 exhibits both anti-inflammatory properties and very remarkable cytotoxicity toward various cancer cell lines with a high value of selectivity index. Additionally, the 3D model representing human pancreas/duct carcinoma (PANC-1) and human lung adenocarcinoma (A549) was designed and applied as a clear proof of the remarkable therapeutic potential of 1. The obtained experimental data indicate that 1 induces an apoptotic pathway via reactive oxygen species generation, targeting mitochondria due to their membrane depolarization. This study broadens a group of bioactive metal-organic networks and highlights the significant potential of such compounds in developing advanced therapeutic solutions.

Versatile Superatom Complex Nanocluster for the Construction of Framework Materials

Accurately controlling the assembly of nanometer-sized building blocks presents an important but significant challenge for the construction of functional framework materials, which requires the development of highly stable versatile nanosized assembly modules with multiple coordination sites. In this study, [Ag₂₃(SAdm)₁₂]³⁺ (Ag₂₃, in which SAdm = 1-adamantanethiol, i.e., C₁₀H₁₅S), a chiral superatom complex nanocluster, was synthesized and assembled into various topologies. We constructed two kinds of framework materials, i.e., superatom complex inorganic framework (SCIF) and superatom complex organic framework (SCOF) materials, including [Ag₂₃(SAdm)₁₂](SbF₆)₂X (Ag₂₃-1; X = Cl^-/SbF₆^-, a SCIF), [Ag₂₃(SAdm)₁₂](SbF₆)₃ (Ag₂₃-2, a SCIF), [Ag₂₃(SAdm)₁₂](SbF₆)₃(bpy)₃ (Ag₂₃-bpy, a SCOF, in which bpy = 4,4'-bipyridine, i.e., C₁₀H₈N₂), and [Ag₂₃(SAdm)₁₂](SbF₆)₃(dpbz)₃ (Ag₂₃-dpbz, a SCOF, in which dpbz = 1,4-bis(4-pyridyl)benzene, i.e., C₁₆H₁₂N₂), owing to strong interactions between the versatile Ag₂₃ and the inorganic and organic linkers. Ag₂₃-1, Ag₂₃-2, and Ag₂₃-bpy exhibit two superstructures with interpenetrating frameworks and adamantane-like, hexagonal, and cubic topologies, while Ag₂₃-dpbz displays three superstructures with interpenetrating frameworks and cubic topologies. Ag₂₃-dpbz exhibits the largest specific surface area as well as the strongest photoluminescence and electrochemiluminescence signals owing to its dense network arrangement. This work contributes to the construction of nanocluster-based framework materials and helps to elucidate the effect of the assembly mode on the material properties and functionalities.

A New Mn(II) Complex: Magnetic Property and Application Values in Foot and Ankle Arthritis

The solvothermal reactions of C3-symmerical 4,4 ${}^{\prime }$ ,4 ${}^{\prime }$ -nitrilotribenzoic acid and MnCl2 afforded a novel Mn(II) compound, and its formula is [Mn3(TCA)2(e-urea)2(DMA)2]n·n(urea)·n(DMA) (1, H3TCA=4,4 ${}^{\prime }$ ,4 ${}^{\prime }$ -nitrilotribenzoic acid, e-urea=2-imidazaolidone, DMA=N,N ${}^{\prime }$ -dimethylacetamide). Magnetic property investigation of 1 indicates weak antiferromagnetic mutual effects exist between neighboring Mn(II) ions. Serial biological tests were adopted to discover new compound activity. Firstly, the enzyme-linked immunosorbent assay (ELISA) was conducted to measure the content of inflammatory cytokines released into the synovial fluid. In addition, we also studied adenosine 5 ${}^{\prime }$ -monophosphate- (AMP-) activated protein kinase (AMPK) inflammatory signaling pathway activation through real-time reverse transcription-polymerase chain reaction (RT-PCR).

Preparation of Laser Energetic Coordination Polymers Based on Urazine by Self-Crystallization

A practical and brilliant way of preparing laser energetic coordination polymers based on crystallization chemistry and coordination theory is proposed in this paper. Design and successful synthesis of urazine (C₂H₄N₄O₂, H₂ur, 1) by the theory of "cyclization of semicarbazides" are reported. Using the "acid-controlled self-crystallization" synthesis method, with H₂ur as the ligand, we successfully synthesized [Ag(H₂ur)₂ClO₄·H₂O]_n (3) and confirmed its composition and 1D structure. In addition, 3 was subjected to a simple drying operation to obtain a solvent-free [Ag(H₂ur)₂ClO₄]_n (4). Also, 4 has the best abilities in physics and chemistry, such as excellent thermal stability, insensitivity to light, mechanical insensitivity, and good corrosion resistance. In particular, thermogravimetric analysis-differential scanning calorimetry-Fourier transform infrared spectroscopy and powder X-ray diffraction were employed to analyze the thermal decomposition products of 4 and demonstrated that the main decomposed products are AgCl, N₂, and H₂O. Moreover, the calculated predictions show that 4 has an acceptable detonation performance (P = 22.5 GPa; D = 6.9 km s^-1). Furthermore, the hot needle examination and detonation experiment show that 4 can be used as a primary explosive. More importantly, as a laser-detonated light-sensitive material, 4 has a significant application value in safety detonators (E = 100 mJ, P = 10 W, and τ = 10 ms).

Therapeutic effect of two transition metal coordination polymers on ovarian cancer by regulating the expression of estrogen receptor

In the present study, via using a ligand featuring oxalamide groups N,N′-bis(4-phthalic acid) (H₄L), two new Cu(II) and Co(II)-containing coordination polymers with the chemical formulae of [Cu₂L(H₂O)₄]_n (1) and [Co(H₂L)(H₂O)₂]_n (2) have been successfully prepared via reaction of the corresponding metal salts with the H₄L ligand. The as-prepared two coordination polymers have been studied via the single crystal X-ray diffraction, elemental analysis, powder X-ray diffraction and thermogravimetric analysis. Their therapeutic effect and mechanism for ovarian cancer was evaluated and explored. Firstly, the inhibitory activity of the new compounds on the proliferation of the ovarian cancer was measured with CCK-8 assay after compound treatment. Besides, the relative expression of the estrogen receptor on the ovarian cancer cells after compound treatment was also determined with real-time RT-PCR assay.

Multifunctional Silver(I) Complexes with Metronidazole Drug Reveal Antimicrobial Properties and Antitumor Activity against Human Hepatoma and Colorectal Adenocarcinoma Cells

Simple Summary

Our previous studies demonstrated that a silver(I) nitrate complex with metronidazole presented greater photo-stability, antimicrobial, cytotoxic and genotoxic properties than silver(I) nitrate. These advantages make the complex a better candidate for clinical therapy than pure salt. Therefore, in this study, we decided to synthetize and determine the chemical, cytotoxic and antimicrobial properties of [Ag(MTZ)₂]₂SO₄, a novel metronidazole silver(I) complex, in comparison with pure salt Ag₂SO₄ and [Ag(MTZ)₂NO₃]. The photo-stability, cytotoxicity toward cancer cells and antimicrobial activity of [Ag(MTZ)₂]₂SO₄ is higher than Ag₂SO₄. What is more, we found that the novel synthetized complex shows better cytotoxicity against cancer cells than [Ag(MTZ)₂NO₃]. Both complexes have similar biological activity against the majority of tested bacterial strains.

Abstract

Silver salts and azole derivatives are well known for their antimicrobial properties. Recent evidence has demonstrated also their cytotoxic and genotoxic potential toward both normal and cancer cells. Still, little is known about the action of complexes of azoles with silver(I) salts. Thus, the goal of the study was to compare the chemical, cytotoxic and antimicrobial properties of metronidazole complexes with silver(I) nitrate and silver(I) sulfate to metronidazole and pure silver(I) salts. We synthetized a novel complex, [Ag(MTZ)₂]₂SO₄, and confirmed its chemical structure and properties using ¹H and ¹³C NMR spectroscopy and X-Ray, IR and elemental analysis. To establish the stability of complexes [Ag(MTZ)₂NO₃] and [Ag(MTZ)₂]₂SO₄, they were exposed to daylight and UV-A rays and were visually assessed. Their cytotoxicity toward human cancer cells (HepG2, Caco-2) and mice normal fibroblasts (Balb/c 3T3 clone A31) was determined by MTT, NRU, TPC and LDH assays. The micro-dilution broth method was used to evaluate their antimicrobial properties against Gram-positive and Gram-negative bacteria. A biofilm eradication study was also performed using the crystal violet method and confocal laser scanning microscopy. The photo-stability of the complexes was higher than silver(I) salts. In human cancer cells, [Ag(MTZ)₂]₂SO₄ was more cytotoxic than Ag₂SO₄ and, in turn, AgNO₃ was more cytotoxic than [Ag(MTZ)₂NO₃]. For Balb/c 3T3 cells, Ag₂SO₄ was more cytotoxic than [Ag(MTZ)₂]₂SO₄, while the cytotoxicity of AgNO₃ and [Ag(MTZ)₂NO₃] was similar. Metronidazole in the tested concentration range was non-cytotoxic for both normal and cancer cells. The complexes showed increased bioactivity against aerobic and facultative anaerobic bacteria when compared to metronidazole. For the majority of the tested bacterial strains, the silver(I) salts and complexes showed a higher antibacterial activity than MTZ; however, some bacterial strains presented the reverse effect. Our results showed that silver(I) complexes present higher photo-stability, cytotoxicity and antimicrobial activity in comparison to MTZ and, to a certain extent, to silver(I) salts.

Structural Diversity of Silver Fluorinated β-Diketonates: Effect of the Terminal Substituent and Solvent

In order to demonstrate the role of the fluorination and some solvents in the structural organization of the Ag(I) coordination polymers with β-diketonate ligands (R1C(O)CαHC(O)R2)- we synthesized a series of the compounds containing tfac- (R1 = CH3, R2 = CF3) and pfpac- (R1 = CH3, R2 = C2F5) anions. Solvent-free [Ag(L)]∞ (L = tfac 1, pfpac 2) compounds and the corresponding acetonitrile and toluene adducts have been characterized by elemental analysis and/or NMR, IR and single-crystal XRD. This series includes five new coordination polymers. Compound 1 is a 3D coordination framework based on Ag-Ochelate/bridge, Ag-Cα bonds, and argentophilic interactions. An increase in the fluorinated group leads to a chain coordination polymer 2 of an unusual structural organization. These chains can be represented as a "DNA-type", where two intertwined helices based on Ag-Ochelate and Ag-Cα bonds are connected through Ag-Obridge ones. Two structural types of chain coordination polymers, [Ag(tfac)(CH3CN)] and [Ag2(L)2(solvent)], have been revealed for the adducts. The latter structural type differs significantly from the previously studied toluene and acetonitrile adducts of fluorinated Ag(I) β-diketonates of the same stoichiometry. Thermal analysis in helium showed that both 1 and 2 decompose to metallic silver with the compound of pfpac-ligand being slightly more stable.

Cholate Conjugated Cationic Polymers for Regulation of Actin Dynamics

Cytoskeletal movement is a compulsory necessity for proper cell functioning and is largely controlled by actin filament dynamics. The actin dynamics can be finetuned by various natural and artificial materials...

Phosphorus or Nitrogen - The first Phosphatriptycene in Coordination Polymer Chemistry

Phosphasilatriptycene, a phenylene spacer and a pyridyl moiety represent the building blocks of TRIP-Py, the first heteroditopic ligand featuring a phoshatriptycene scaffold. The P and N donor sites located at...