Binuclear Silver Complexes Research Articles

In vitro and in silico anticancer potential of binuclear silver (I) N-heterocyclic carbene (NHCs) complexes: Investigation of interaction with surfactants

N-heterocyclic carbene (NHCs) silver complexes are getting tremendous attention for appealing biological potentials. The present study is planned to synthesize silver-NHC complexes to investigate their anticancer potential against breast, colon and ovarian cancer cell lines. The synthesized benzimidazolium salts (C1-C2) and their binuclear silver complexes (C3-C4) were assured through spectroscopy (UV–visible, FTIR, NMR and FLR), HPLC-DAD (high performance liquid chromatography), elemental analysis as well as mass spectrometry. Molecular docking studies indicated that compound C4 has lower binding energy values of −4.49, −1.95 and −2.95 kcal/mol for Bruton’s tyrosine kinase, Human topoisomerase II alpha and Aromatase cytochrome P450 protein targets respectively. The In Vitro cytotoxicity assay confirmed the C4 is better cytotoxic agent from other studied compounds of present study having lower IC50 values of 0.996 ± 0.04, 0.97 5 ± 0.04, 0.872 ± 0.05 and 0.987 ± 0.05 µg/mL against MCF-7, A-549, A-2780 and HCT-116 cell lines. Stability of compounds in solution form studied through spectroscopy and all compounds were found stable for studied course of time. Interactions of C3-C4 with surfactants (SDS, tween-20, tween-80) have confirmed the substantial interaction to improve aqueous solubility. Interaction of C3-C4 with surfactants indicates that there is potential affinity among test compounds and surfactants for complex formation spontaneously, having strongest binding affinity for SDS (sodium dodecyl sulfate) as compared to Tween-20 and Tween-80.

Coordination chemistry of silver(I), gold(I) and nickel(II) with bis N-heterocyclic carbenes: applications in electrocatalytic hydrogen evolution reaction

The design and systematic investigation of an electrocatalyst is crucial in ensuring proper benchmarking of the catalyst developed. This perspective has led to molecular catalysts developed from N-heterocyclic carbene (NHC) metal complexes for electrocatalytic applications. Among the array of electrocatalytic applications available, hydrogen evolution reaction (HER) is at the forefront due to the ever-increasing demand for cleaner and sustainable energy. This work is focussed on the development of binuclear metal-NHC complexes from bis-{4-(2,6-diethylphenyl)-1,2,4-triazole} with a propyl spacer and hexafluorophosphate counterion. The NHC precursor and binuclear silver complexes prepared have been elucidated by single-crystal X-ray diffraction. An assessment of the binuclear complex bearing the same ligand with nickel(II) resulted in the formation of a counter held nickel derivative. The electrocatalytic performance of these metal organic derivatives in HER is evaluated along with their electrochemical impedance spectral discussion.

Poly[dipotassium [(μ6-2,2',2'',2'''-{[pyrazine-2,3,5,6-tetra-yltetra-kis-(methyl-ene)]tetra-kis-(sulfanedi-yl)}tetra-acetato)-disilver(I)] 5.2-hydrate

The reaction of AgNO3 with the ligand 2,2',2'',2'''-{[pyrazine-2,3,5,6-tetra-yltetra-kis-(methyl-ene)]tetra-kis-(sulfanedi-yl)}tetra-acetic acid in the presence of a potassium acetate buffer lead to the formation of a silver(I)-potassium-organic framework, poly[dipotassium [(μ6-2,2',2'',2'''-{[pyrazine-2,3,5,6-tetra-yltetra-kis(methyl-ene)]tetra-kis-(sulfanedi-yl)}tetra-acetato)-disilver(I)] 5.2-hydrate], {K2[Ag2(C16H16N2O8S4)]·5.2H2O} n , (I). The asymmetric unit is composed of half a binuclear silver complex located about a center of symmetry, a potassium cation and 2.6 disordered water mol-ecules. The whole binuclear silver complex is generated by inversion symmetry with the pyrazine ring being located about an inversion centre. The ligand coordinates in a bis-tetra-dentate manner. The binuclear silver complex anions are linked via bridging Ag⋯S⋯Ag zigzag bonds, forming a network lying parallel to the bc plane. The networks are linked by Ocarboxyl-ate⋯K +⋯Ocarboxyl-ate bridging bonds to form a framework. The disordered water mol-ecules are present near to the K+ cations.

Ligand influence on the formation of exo-coordinated silver(I) complexes with N2O2 Schiff base macrocycles and the role of anion in supramolecular aggregation

Three novel silver(I) complexes with N2O2-donor macrocyclic Schiff bases L1 and L2 (L1 = 1,5-diaza-2,4:7,8:17,18-tribenzo-9,16-dioxa-cyclononadeca-1,5-dien; L2 = 1,5-diaza-2,4:7,8:18,19- tribenzo-9,17-dioxa-cycloeicosa-1,5-dien) were prepared by the reaction of the corresponding macrocycles with silver nitrate and silver perchlorate in 1:1 stoichiometric ratio. The reactions of macrocyclic ligands (L1 and L2) with silver perchlorate led to the formation of unusual (regarding donor set atoms) silver coordination polymers, AgL1ClO4, and (AgL2ClO4)2·CH2Cl2. The reaction of L2 with silver nitrate resulted in a formation of discrete binuclear silver complex (AgL2NO3)2. In all three compounds, silver ions are exo-coordinated due to the presence of rigid CN bond in the molecular structure of ligands in which nitrogen atom non-bonding electron pairs are exo- oriented. All synthesized compounds were characterized by vibrational spectroscopy (IR) and thermal methods (TG/DSC). The crystal and molecular structures of silver complexes were determined by the single crystal X-ray diffraction method. In the complex AgL1ClO4, each silver atom is coordinated by two ligand molecules and one perchlorate anion (T-shaped geometry). The coordination geometry around the silver atom can be described as T-shaped, resulting in a formation of the 1D zig-zag polymeric chain. In (AgL2ClO4)2·CH2Cl2 two distinct coordination surroundings of silver ions that can be divided into cationic (linear geometry) and anionic (square planar geometry) part. The topology of the polymeric chain can be described as a 1D zig-zag. The silver atoms in (AgL2NO3)2 are tetrahedrally coordinated with two N-bound ligand molecules and one nitrate anion (bidentate). This form of coordination produces a discrete bimetallic silver complex with an additional metallacyclic ring. The anion and ligand influence on the chain structure is attributed to the presence of rigid imine double bond and partly to the coordination ability of counter ions.

Synthesis and properties of 1,3-bis[(2-bromo)benzene]triazene and its binuclear silver complex

The reaction of 2-bromoaniline with sodium nitrite affords a triazenido compound, 1,3-bis[(2-bromo)benzene]triazene (HL). Spectroscopic investigations show that HL bears a high selectivity for silver(I) ion in the presence of other metal ions. In the presence of Et3N, the reaction of HL and AgNO3 gives a binuclear triazenido-silver complex, [Ag2(L)2], which has been determined by X-ray diffraction analysis. Electrochemical studies show this silver complex can act as an electrocatalyst for hydrogen generation from neutral water with a turnover frequency (TOF) of 874.14 moles of hydrogen per mole of catalyst per hour (mol H2/mol catalyst/h) at an over potential (OP) of 837.6 mV.

Synthesis of a new binuclear silver(I) complex with the ability to interact with DNA molecule

A new binuclear silver complex, [Ag2(FcCOO)2(dppm)2].2CH3CN, Fc-COOH = ferrocenecarboxylic acid, dppm = bis(diphenylphosphino)methane, with the ability to form binding with DNA molecule, was synthesized and its structure determined by elemental analysis, FT-IR, 13C NMR, 31P NMR and X-ray crystallography. Considering the potential of the complex A1 in the cancer treatment, the interaction of this complex with calf thymus DNA (CT-DNA) was investigated by using electronic absorption spectra, fluorescence and redox behavior techniques. The experimental results showed that there is an electrostatic interaction between complex and CT-DNA.

A binuclear silver complex with l-buthionine sulfoximine: synthesis, spectroscopic characterization, DFT studies and antibacterial assays

A binuclear silver(I) complex with the amino acid L-buthionine sulfoximine (BSO) of composition Ag2C8H16N2O3S was synthesized and characterized by chemical and spectroscopic measurements, and DFT (density functional theory) studies. Solid-state 13C nuclear magnetic resonance (SSNMR) and infrared vibrational spectroscopy (IR) analyses indicate the coordination of the nitrogen and carboxylate groups of the amino acid moiety to one of the silver atoms, while coordination to the second silver atom occurs through the nitrogen of the sulfoximine group. ESI-QTOF-MS measurements show the maintenance of the binuclear structure in solution. DFT studies confirm the proposed structure as a minimum of the potential energy surface (PES) with calculations of the hessians showing no imaginary frequencies. Raman spectroscopic measurements of the [Ag2(BSO)] complex led to the assignments of the Ag–N bonds. Biological assays of BSO and [Ag2(BSO)] were performed by the well-diffusion method over Staphyloccocus aureus (Gram-positive), Escherichia coli and Pseudomonas aeruginosa (Gram-negative) bacterial strains. The ligand was inactive under the tested concentration (100 μg mL−1). The [Ag2(BSO)] complex was active against the Gram-negative and Gram-positive bacteria tested, with MIC values of 3.125 μg mL−1.

Structure of a binuclear silver(I) complex [Ph3PAg(O2CCH2Ph)

The reaction of [Ph3PAgI]4 with sodium phenylacetate in MeOH and CH2Cl2 at room temperature gave rise to a binuclear silver complex with triphenylphosphine and phenylacetate mixed ligands, [Ph3PAg(O2CCH2Ph)]2. The crystal and molecular structure of the complex has been determined by single crystal X-ray diffraction analysis. The space group is $$P\bar 1$$ witha=9.198(2),b=9.516(2),c=13.842(3) A, α=102.00(3), β=108.34(3), γ=93.58(3)°,Z=1, andDc=1.506 g cm−3. The silver atoms are each coordinated by one phosphorus atom from triphenylphosphine and two oxygen atoms from the carboxylate groups in a T-shape. The complex is further characterized by its IR,1H, and31P NMR spectra.

Paramagnetic silver complexes with ammonia in zeolites

The intermediate paramagnetic species formed in gamma-irradiated Ag NaA zeolites with adsorbed ammonia have been studied by ESR spectroscopy. For zeolites with silver loadings of about one Ag + ion per unit cell, the reaction of silver atoms with ammonia molecules above 180 K leads to the formation of paramagnetic silver—ammonia adducts Ag·NH 3 with the unpaired electron residing on both the silver and the nitrogen nuclei. For silver loadings of about six Ag + ions per unit cell, the formation of binuclear silver complexes with two magnetically non-equivalent Ag nuclei coordinated by NH 3 ligands is proposed based on line shape simulations of broad-line ESR septets.