Complexation Of Silver Ions Research Articles

Adsorption of silver ions onto chitosan hydrogel: Structural studies

Chitosan indicate a significant potential in the field of water treatment due to polymer high porosity, large specific surface area and its ability to bind strongly heavy metal ions form aqueous solutions. Therefore, chitosan based hydrogels have been fabricated by physical crosslinking of the polymer chains via sol–gel method using sodium β-glycerophosphate (β-GP) for silver ions (Ag) removal from water solutions. The aim of this study was to provide experimental studies under batch conditions to perform adsorption isotherm and evaluate the effect of silver adsorption onto chitosan hydrogel morphological and structural changes using SEM, XRD, FTIR and EDX analyses. Obtained results provides the data on the structural changes in the chitosan hydrogels under Ag adsorption process. The FTIR spectra confirmed that the C-NH2 and OH groups contribute to the formation of chitosan - silver ion complexes. The presence of adsorbed Ag in the samples < 0.8 gAgL−1 were evidenced by the characteristic peak at 2θ = 46.35°. Regarding to EDX analysis the adsorption efficiency toward Ag ions, rises with an increase in Ag initial concentration, resulting in L-type isotherm. The percentage removal of silver ions efficiency obtained 34 % for the highest Ag initial concentration (10 gAg L−1). SEM micrographs after Ag adsorption performed morphology as homogeneous porous network and reveals Ag present in the structure resulting from effective Ag adsorption. This study verified structural changes resulted from silver ions adsorption and confirmed the potential for thermosensitive chitosan hydrogels to applied as an adsorbent for water treatment applications.

Red Room-Temperature Phosphorescence Supramolecular Assemblies Based on Cucurbit[7]uril: Reversible Temperature Stimulation Response and Cell-Specific Silver Ion Imaging.

Solid-state materials with efficient room-temperature phosphorescence (RTP) emission have been widely used in materials science, and organic RTP-emitting systems with heavy-metal doping in aqueous solutions have attracted much attention in recent years. A novel supramolecular interaction was induced by host-guest assembly using cucurbit[7]uril (Q[7]) as the host and brominated naphthalimide phosphor as the guest. This interaction was further enhanced through synergistic chelation stimulated by analytical silver ion complexation. This approach facilitated the system's structural rigidity, intersystem crossing, and oxygen shielding. We achieved deep red phosphorescence emission in aqueous solution and ambient conditions along with quantitative determination of silver ions. The new complex exhibited good reversible thermoresponsive behavior and was successfully applied for the first time to target phosphorescence imaging of silver ions in the mitochondria of A549 cancer cells. These results are beneficial for constructing novel RTP systems with stimulus-responsive luminescence in aqueous solution, contributing to future research in bioimaging, detection, optical sensors, and thermometry materials.

Comparing π-complexation capabilities of ionic liquids containing silver(I) and copper(I) ions by headspace single drop microextraction in combination with high-performance liquid chromatography.

Selective π-complexation capabilities of silver(I) and copper(I) ions can be effectively facilitated in ionic liquids. To understand the effects of environmental factors that influence the π-complexation of these metal ions with analytes, techniques that employ small volumes of ionic liquid that can be readily analyzed are desired. In this study, headspace single drop microextraction coupled with HPLCis used to investigate a diverse set of environmental factors on the metal ion-mediated complexation with aromatic compounds in ionic liquid media. Silver(I) and copper(I) bis[(trifluoromethyl)sulfonyl]imide salts were both studied by dissolving them in the 1-decyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide ionic liquid and employing the mixture as extraction media for aromatic compounds. Water and acetonitrile within the sample solution were observed to interfere with the complexation of silver(I) ions and aromatic compounds, while ethylene glycol and triethylene glycol did not. The temperature and extraction times were optimized to fully facilitate the π-complexation capabilities of metal ions in ionic liquid media. Partition coefficients between the sample headspace and metal ion were determined using a three-phase equilibria model. Although no discernable difference in analyte partitioning between the headspace and ionic liquid solvent was observed, analyte partition coefficients to silver(I) ion tended to be greater compared to copper(I) ion.

Computational Study on the Nature of Bonding between Silver Ions and Nitrogen Ligands.

In this paper, the nature of silver ion-nitrogen atom bonding in the complexation with ammonia, azomethine, pyridine, and hydrogen cyanide from one to four coordinations is studied at the B97-1 level of density functional theory. The results indicate that the two-coordinated complex of the silver ion with different nitrogen ligands representing sp, sp2, and sp3 orbital hybridizations is the most stable form having the shortest Ag+-N bond distance, highest vibrational frequencies, largest bond order, and favorable Gibbs free energy of formation. Natural bond orbital analyses further show that σ-donation from the nitrogen lone pair to the silver empty 5s orbital is dominant in the dative metal-ligand bonding character with N-sp3 having the largest contribution among the different N atomic orbital hybridizations. Natural energy decomposition analyses further show that the two-coordinated complexes have enhanced electrostatic interaction and charge transfer energies over other coordination types leading them to be more stable. For this reason, the two-coordinated complexes would be a better representation for studying bonding and interaction in silver ion complexes.

Structure, bonding, and interaction with molecular hydrogen of the β‐D‐glucopyranose―silver+ (1:1) complex

AbstractIn silico studies have been carried out at PBE0‐D3/def2‐TZVP level of theory to disclose the nature of bonding in β‐D‐glucopyranose – silver ion (1:1) complex ([Ag(C6H12O6)]+). Moreover, the interaction of molecular hydrogen with the [Ag(C6H12O6)]+ complex is studied. In doing so, it is found that the metal site can interact with up to three hydrogen molecules with a binding energy of 5.3 kcal/mol per H2. Calculated ∆G298 K values disclose that the interaction of the first H2 with the [Ag(C6H12O6)]+ complex is exergonic, whereas a slightly endergonic nature of interaction is noted for the two and three H2 cases. Electron density and electron density‐based reactivity descriptors help in resolving the nature of interaction between metal ions and C6H12O6 as well as between the metal center and molecular hydrogens. An energy decomposition analysis reveals the orbital interaction as the major contributing factor to the total interaction energy for the one H2 case. Ab initio molecular dynamics study at different temperatures reveals kinetic stability of the hydrogen‐bound silver complex up to 1 ps. Conceptual density functional theory (CDFT) based reactivity descriptors, hardness and electrophilicity, help in assessing the stability trend of the hydrogen‐bound complexes during the simulation.

Synthesis of silver nanoparticles (AgNPs) of leaves extract of Rhynchoglossum notonianum wall. for enhancing its bioavailability and antibacterial activity

Objective: Silver nanoparticles (AgNPs) derived from Rhynchoglossum notonianum Wall. leaf were the subject of this investigation to examine their synthesis, characterisation, and biological activity. Materials and Methods: Aqueous extracts of Rhynchoglossum notonianum Wall leaves and 0.1 M silver nitrate were used to make AgNPs. Particle size, Zeta potential, UV-Vis spectroscopy, and SEM were used to determine the AgNPs properties. Results: Rapid and homogeneous size and shape silver nanoparticles were synthesised utilising Rhynchoglossum notonianum Wall. extract. When methanolic leaf extracts of Rhynchoglossum notonianum Wall. were combined with an aqueous silver ion complex solution, the surface Plasmon vibrations were excited, resulting in the production of MERNAgNPs. UV-Visible spectroscopy was used to characterise the nanoparticles. The widening of the peak in the UV-visible spectrum suggested polydispersion. The silver nanoparticles in solution have a surface Plasmon band of 420nm. Aqueous silver nitrate solution is diffused throughout the reaction time, with no signs of agglomeration. The average particle size (z-average) was “132.6nm”, the polydispersity index was “0.248”, and the zeta values were -25.1mV with a 100% peak area. This implies a stable silver nanoparticle.

Cover Image

The cover image is based on the Research Article Competition between the stabilizing effects of saturated alkyl substituents and pi bonds on complexes of silver ion (Ag+) with alkenes by Gary W. Breton, https://doi.org/10.1002/poc.4301.

Switchable silver-ion complexation by triazolated calix[4]semitubes.

Triazolated calix[4]semitubes comprising several binding sites were studied for complexation of Ag+ to get insight into the ability of the multitopic semi-tubular environment to host cation(s) in a structure-specific/switchable manner. For this purpose, a series of triazolated calix[4]semitubes having two or three 1,3-alternate calix[4]arene cores and crown-5-ether loops in the structures were prepared using the recently developed stepwise synthesis approach. Crown-5-ether loops were used as model receptor units which could be filled with K+ to charge positively either a specific 'end' or both 'ends' of the semi-tubular assemblies and to affect the complexation abilities of the internal binding sites of triazolated calix[4]semitubes. Comparative analysis of complexation-induced broadening in the 1H NMR spectra of three isomeric tris(calixarenes) having different mutual arrangements of the internal binding sites upon addition of Ag+ suggested intramolecular rather than intermolecular migrations of the bound cation between two bistriazole units. The study on Ag+/K+ complexation by the crowned biscalixarene semitubes revealed strong dependence of the ditopic complexation mode on the mutual arrangement of the triazole and crownether sites within the molecule, which managed either the heterodinuclear Ag+/K+ binding, or switching between two single-nuclear complexes. In crowned triscalixarene semitubular systems, the same structure/complexation mode correlation was observed, but in this case, binding of K+ by an appropriately arranged crownether loop did not destroy the initial silver complex, but stopped the above migrations of Ag+ between the internal sites of heteromultitopic ligands, thus indicating the applicability of the triscalixarene semitubular core for the design of multipositioned molecular switches.

Competition between the stabilizing effects of saturated alkyl substituents and pi bonds on complexes of silver ion (Ag+) with alkenes

AbstractThe coordination of Ag+ ions to alkenes is of both theoretical and practical interest. While much attention has been paid to how the nature of the C=C π bond affects the coordinative process, little attention has been directed toward the effect of saturated side chains on complex stabilization despite experimental evidence suggesting its importance. Calculations employing the M06‐2X DFT functional have revealed that saturated chains can exhibit as powerful a stabilizing effect on Ag+/alkene complex formation as increased alkyl substitution about the C=C bond. Natural bond orbital (NBO) analysis confirms the mechanism of stabilization to be that of agostic interactions of properly‐oriented CH σ‐bonds in the saturated chain with the Ag+ ion. Analysis by the extended transition state energy decomposition approach with the natural orbital for chemical valence method (ETS‐NOCV) and the reduced density gradient (RDG) model were used to better characterize the nature of the interaction as a near equivalent combination of electrostatic and orbital interactions.

Silver Ion-Complexation High-Speed Countercurrent Chromatography Coupled with Prep-HPLC for Separation of Sesquiterpenoids from Germacrene A Fermentation Broth

A silver ion high-speed counter-current chromatography ([Ag+]-HSCCC) was developed to separate and purify five sesquiterpenoids from germacrene A fermentation broth. The solvent system was consisted of n-hexane-methanol-silver nitrate (3 mol/L) solution (10:9.5:0.5, v/v). By employing this chromatographic protocol, five sesquiterpenoids named β-elemene (1; 54.1 mg), germacrene A (2; 28.5 mg), γ-selinene (3; 4.6 mg), β-selinene (4; 3.4 mg), and α-selinene (5; 1.3 mg) were obtained successfully from 500 mg extracted crude sample with purities of 97.1%, 95.2%, 98.2%, 96.3% and 98.5%, respectively, combined with preparative HPLC. The results reveal that the addition of metal ion in biphasic solvent system significantly improved the HSCCC separation factor of sesquiterpenoids. Meanwhile, our study also provided an alternate approach to separate the compounds with less polarity, also geometrical isomers and various natural product classes.

Potentiometer study of the process of complexation of silver (I) ions with thiourea

The process of complexation of silver(I) ions with thiourea (Tu) in the temperature range 287.16&ndash;318.16 K at an ionic strength of 0.11 M (I = 0.1 NaNO3 + 0.01 HNO3) was studied by the potentiometric method using a silver electrode in aqueous solution. The study was performed at a concentration of silver(I) ions CAg+ = 1 &middot; 10&ndash;5 and CAg+ = 1 &middot; 10&ndash;3 M. The values of the stability constants of AgTui + complexes (i = 1&ndash;2) were estimated at CAg+ = 1 &middot; 10&ndash;5 M. The AgTu3+ complex constant was determined at CAg+ = 1 &middot; 10&ndash;3 M and CTu &ge; 0.01 M. The stability constants of complexes were calculated using the Leden method. The values of the complex constants at 298.16 K are equal to: lg&beta;1 = 5.59 &plusmn; 0.10 (AgTu+), lg&beta;2 = 10.62 &plusmn; 0.03 (AgTu2+) and lg&beta;3 = 13.05&plusmn;0.11 (AgTu3+). It is established that the temperature effect does not affect the number of formed particles in the solution; an increase in temperature leads to a decrease in the stability of complexes. The analysis of the values of the stability constants by degrees shows that the step constants AgTu3+ (AgTu2+ + Tu = AgTu3+ + lg&beta;3 = 2.4) are much smaller than the constants for mono- and bis-coordinated complexes. The complexes thermodynamic parameters (&Delta;H0, &Delta;G0, &Delta;S0) were calculated by the temperature coefficient method. In the system under study, all complexation reactions are exothermic. The largest increase in the value of enthalpy (&Delta;H0) is observed in the formation of a complex containing two molecules of thiourea. The change in entropy (&Delta;S0) at the stage of formation of bis- and tris-coordinated complexes is negative, which is most likely due to a decrease in the number of particles in the system under study. It is determined that enthalpy-entropy dependences show a monotonic character. The spontaneous course of complexation reactions is determined by the value of the free Gibbs energy (&Delta;G0). In degrees G0 decreases (&Delta;G0)1 &lt; (&Delta;G0)2 &lt; (&Delta;G0)3) and has a negative value, which indicates a decrease in the affinity of the complexing agent to the ligand.

One-Step Synthesis of Green Fluorescent Carbon Dots for Chloride Detecting and for Bioimaging.

The chloride ion is an essential ion in organisms, which plays an important role in maintaining normal cell functions. It is involved in many cell activities, such as cell proliferation, cell excitability regulation, immune response, and volume regulation. Accurate detection of the chloride ion can balance its concentration in vivo, which is of great significance. In this study, we developed a green fluorescent carbon quantum dot to detect chloride concentration through the “off–on” mechanism. First, the fluorescence of carbon dots is quenched by the complex of sulfhydryl and silver ions on the surface of carbon dots. Then, the addition of chloride ions pulls away the silver ions and restores the fluorescence. The fluorescence recovery is linearly related to the concentration of chloride ions, and the limit of detection is 2.817 μM, which is much lower than those of other reported chloride probes. Besides, cell and zebrafish experiments confirmed the biosafety and biocompatibility of the carbon dots, which provided a possibility for further applications in bioimaging in vivo.

Reagent free electrochemical-based detection of silver ions at interdigitated microelectrodes using in-situ pH control

• Applying 1.65 V to a protonator electrode lowered the pH at the sensor electrode to pH 3, optimal for silver ion detection. • In-situ pH control eliminated the need for the addition of mineral acids to a solution before analysis. • Chlorine present in tap water helped in detection, causing a sharpening of the silver stripping peak due to formation of silver chloride. • Detection of 250 nM of silver ions in tap water in less than 3 min was possible without the need for additional electrolytes. Herein we report on the development of an electrochemical sensor for silver ions detection in tap water using anodic sweep voltammetry with in-situ pH control; enabled by closely spaced interdigitated electrode arrays. The in-situ pH control approach allowed the pH of a test solution to be tailored to pH 3 (experimentally determined as the optimal pH) by applying 1.65 V to a protonator electrode with the subsequent production of protons, arising from water electrolysis, dropping the local pH value. Using this approach, an initial proof-of-concept study for silver detection in sodium acetate was undertaken where 1.25 V was applied during deposition (to compensate for oxygen production) and 1.65 V during stripping. Using these conditions, calibration between 0.2 and 10 μM was established with the silver stripping peak ∼0.3 V. The calculated limit of detection was 13 nM. For the final application in tap water, 1.65 V was applied to a protonator electrode for both deposition and stripping of silver. The chloride ions, present in tap water (as a consequence of adding chlorine during the disinfection process) facilitated silver detection and caused the striping peak to shift catholically to ∼0.2 V. The combination of the complexation of silver ions with chloride and in-situ pH control resulted in a linear calibration range between 0.25 and 2 μM in tap water and a calculated limit of detection of 106 nM without the need to add acid or supporting electrolytes.

Ultrafast excited state dynamics of silver ion-mediated cytosine-cytosine base pairs in metallo-DNA.

To better understand the nexus between structure and photophysics in metallo-DNA assemblies, the parallel-stranded duplex formed by the all-cytosine oligonucleotide, dC20, and silver nitrate was studied by circular dichroism (CD), femtosecond transient absorption spectroscopy, and time-dependent-density functional theory calculations. Silver(I) ions mediate Cytosine-Cytosine (CC) base pairs by coordinating to the N3 atoms of two cytosines. Although these silver(I) mediated CC base pairs resemble the proton-mediated CC base pairs found in i-motif DNA at first glance, a comparison of experimental and calculated CD spectra reveals that silver ion-mediated i-motif structures do not form. Instead, the parallel-stranded duplex formed between dC20 and silver ions is proposed to contain consecutive silver-mediated base pairs with high propeller twist-like ones seen in a recent crystal structure of an emissive, DNA-templated silver cluster. Femtosecond transient absorption measurements with broadband probing from the near UV to the near IR reveal an unusually long-lived (>10 ns) excited state in the dC20 silver ion complex that is not seen in dC20 in single-stranded or i-motif forms. This state is also absent in a concentrated solution of cytosine-silver ion complexes that are thought to assemble into planar ribbons or sheets that lack stacked silver(I) mediated CC base pairs. The large propeller twist angle present in metal-mediated base pairs may promote the formation of long-lived charged separated or triplet states in this metallo-DNA.

Physico-chemical study of complexation of silver ion (Ag+) by macrocyclic molecules (hexa-Helicenes) based on statistical physics theory: new description of a cancer drug

In recent papers, it is found that the silver-[6]Helicene complex can be used as a cancer drug but the interaction silver-hexaHelicene has not yet proven. The idea of this paper is to investigate the complexation process of the [6]Helicene by the silver metal (Ag+) using three types of adsorbates. Indeed, the adsorption of silver chloride, silver nitrate and silver sulfide into the sensor films deposited on the QCM electrode are measured at three temperatures (293–333 K). Films of the [6]Helicene were deposited on the QCM resonators using spin coating method in order to obtain uniform and homogenous sensor surface. Experimental results indicated that the [6]Helicene can form a stable complex with the silver ion and that the AgCl is the appropriate adsorbate for the complexation achievement. Actually, an advanced modeling analysis by means of statistical physics adsorption models is applied to explore the new vision of the complextion system. The values of the models parameters are deduced from fitting the experimental data with the developed models. They result in confirming the experimental findings by comparing the complexation energies of the three examined systems. In particular, for the silver nitrate, the Van-der-Waals parameters explained the isotherms drop at high concentration through the lateral interactions between the adsorbates. The adsorption energies analysis showed the highest interaction AgCl-[6]Helicene. Density functional theory (DFT) simulations showed that chemical bonds take place during the adsorption of silver chloride on hexaHelicene which confirms that the [6]Helicene can function as a chiral molecular tweezer of the univalent cationic silver.

The Complexation of Silver (I) ion with 18-Crown-6 Ether in Water and Some Polar Aprotic Solvents

The process of complexation of silver (I) ions with 18-crown-6 ether in some polar water-aproton solvents at a constant temperature of 308К was studied by direct potentiometric titration. The stability constants of the resulting complex are determined depending on the molar fraction from 0.2 to 0.8 dimethylsulfoxide and dimethylformamide in the composition of the mixed solvent. It is shown that, despite the same nature of the co-solvents, they have the opposite effect on the stability constant of the complex due to the instability of DMF in an acidic medium and when heated. It is noted that the studied reaction is exothermic and the temperature increase reduces the stability of the studied complexes

An unknown component of a selective and mild oxidant: structure and oxidative ability of a double salt-type complex having κ1O-coordinated permanganate anions and three- and four-fold coordinated silver cations.

Compounds containing redox active permanganate anions and complexed silver cations with reducing pyridine ligands are used not only as selective and mild oxidants in organic chemistry but as precursors for nanocatalyst synthesis in low-temperature solid-phase quasi-intramolecular redox reactions. Here we show a novel compound (4Agpy2MnO4·Agpy4MnO4) that has unique structural features including (1) four coordinated and one non-coordinated permanganate anion, (2) κ1O-permanganate coordinated Ag, (3) chain-like [Ag(py)2]+ units, (4) non-coordinated ionic permanganate ions and an [Ag(py)4]+ tetrahedra as well as (5) unsymmetrical hydrogen bonds between pyridine α-CHs and a permanganate oxygen. As a result of the oxidizing permanganate anion and reducing pyridine ligand, a highly exothermic reaction occurs at 85 °C. If the decomposition heat is absorbed by alumina or oxidation-resistant organic solvents (the solvent absorbs the heat to evaporate), the decomposition reaction proceeds smoothly and safely. During heating of the solid material, pyridine is partly oxidized into carbon dioxide and water; the solid phase decomposition end product contains mainly metallic Ag, Mn3O4 and some encapsulated carbon dioxide. Surprisingly, the enigmatic carbon-dioxide is an intercalated gas instead of the expected chemisorbed carbonate form. The title compound is proved to be a mild and efficient oxidant toward benzyl alcohols with an almost quantitative yield of benzaldehydes.

Effect of reactant solvation on the stability of complexes of silver(I) with 18-crown-6 in ethanol-dimethyl sulfoxide mixtures

The effect of solvation on the stability of the complexes of silver(I) ion with 18-crown-6 ([Ag18C6]+) upon the change of the solvent composition (EtOH → (EtOH-DMSO)) was investigated. Gibbs energy of transfer of both silver(I) ion and the macrocyclic ligand employed (18-crown-6) from pure ethanol to ethanol-dimethyl sulfoxide mixtures (DMSO) were obtained by potentiometry and by determining the distribution between two immiscible phases at 25 °C, respectively. An increase of DMSO content in the binary mixture results in an increase of the differences in the solvation of the central ion and the complex. This shifts the equilibrium of complex formation towards the formation of products. We show that the relationship between changes in the stability of the coordination compound and changes in the solvate state of the reactants is sufficiently regular to allow for the prediction of changes in the stability of [Ag18C6]+ when a non-aqueous solvent is increasingly replaced by another non-aqueous solvent.

One-pot inorganic route to highly stable water-dispersible Ag2S quantum dots

Direct aqueous synthesis of Ag2S QDs is a challenge because hydrophobic Ag2S QDs tend to aggregate to form large polycrystals. In this article, the low temperature one-pot route for obtaining highly stable aqueous colloid solutions of Ag2S QDs, using NH3 molecules as monodentate ligands, is reported. Ionic forms of all the species in solution including free ligand, free and complex silver ions, and free sulfide ions at any given experimental pH were calculated. The obtained speciation diagrams were necessary to determine synthetic parameters such as concentration ratios [Ag+]/[HS−] and [NH3]/[Ag+], and pH. The comprehensive investigation of Ag2S QDs' colloid solutions was carried out by high-resolution transmission electron microscopy (HR-TEM) and scanning transmission electron microscopy (STEM), UV–vis–NIR spectroscopy, dynamic light scattering. The Ag2S QDs possessed monoclinic (acanthite) crystalline structure with an average size about 33 nm. Estimations of hydrodynamic diameter and degree of double layer charge in colloid solutions, i.e. the ς-potential measurements, proved high stability of colloidal system of Ag2S QDs on the order of several months under ambient conditions. Combination of both electrostatic and steric stabilization mechanisms kept Ag2S QDs uniformly dispersed in aqueous medium, with NH3 molecules playing a crucial role in avoiding aggregation of as-prepared Ag2S QDs. Colloid Ag2S QDs exhibited NIR emission at 1280 nm under 808 nm excitation.

Synthesis, Characterization and Antimicrobial properties of Methylbenzyl and Nitrobenzyl containing Imidazolium-based Silver N-Heterocyclic Carbenes

A series of imidazolium-based novel ionic liquids (ILs) containing methylbenzyl and nitrobenzyl substituents were prepared and further converted to neutral as well as ionic silver complexes. The ILs and their Ag-NHCs (N-Heterocyclic Carbenes) were successfully characterized by NMR, FT-IR, and EI-MS studies. The ILs and Ag-NHCs were screened for antimicrobial activity based on the zone of inhibition, Minimum Inhibitory Concentration (MIC) determination, and stability studies against Salmonella enterica and Staphylococcus aureus. The neutral complex NS-32 ((1-((2′-cyano-[1,1′-biphenyl]-4-yl)methyl)-3-(4-nitrobenzyl)-2,3-dihydroimidazol-2-yl)silver bromide) was the most active with MIC of 25μM and showed efficient growth inhibition of bacterial pathogens even up to 21d. The complex NS-32 was further monitored for cell wall disruption by scanning electron microscopy (SEM). The photomicrographs of bacterial cells obtained by SEM after treatment of NS-32 with S. enterica and S. aureus showed rupture of a cell wall, thus proving it to be the site of action and ultimately having inhibitory effects on the microbial cell growth.