Mechanism of 3,3′-Disulfopropyl-5,5′-Dichlorothiacyanine Anion Interaction With Citrate-Capped Silver Nanoparticles: Adsorption and J-Aggregation

Abstract

The paper presents the results of the experimental and theoretical study of 3,3′-disulfopropyl-5,5′dichlorothiacyanine sodium salt (TC) adsorption and Jaggregation on the surface of citrate-capped silver nanoparticles (AgNPs) with an average particle size 10 nm. Various nanospectroscopy techniques such as UV−vis, TEM, AFM, DLS, ζ potential, and fluorescence measurements were carried out in order to characterize the hybrid system. Besides this, a set of simple density functional theory calculations (DFT) was performed and this suggested that TC dye, from the thermodynamical point of view, most likely interacted with AgNPs via oxygen atom from SO 3 − groups. The methods, which considered AgNPs as the macromolecule with several binding sites and TC dye as the ligand, were applied for the analysis of saturation curves constructed from the fluorescence data to obtain the binding constant (K a = 1.5 × 10 6 M −1 ) and the average number of TC dye molecules bonded per AgNP (∼330). Moreover, TC fluorescence was quenched in the presence of AgNPs on the concentration dependent manner, yielding the linear Stern−Volmer relation accounting for both static and dynamic quenching with the quenching constant K sv = 2.5 × 10 8 M −1 . Kinetic measurements of J-aggregation as the dependence of AgNPs/TC concentration ratio confirmed that the J-aggregation occurred via a two-step process, the first of them being the initial adsorption of dye on AgNPs surface, followed by dye molecules rearrangement and the consecutive growth of TC aggregate layers.

Solid‐State Synthesis of Silver Nanoparticles and Their Catalytic Application in Methylene Blue Reduction

“…It is well known that Ag NPs possess an intense surface plasmon resonance band, therefore the indication for Ag NPs formation was monitored by UV‐Vis spectrophotometry. Absorption spectra show band characteristic for spherical Ag NPs with a maximum centered at 417 nm (Figure ). The position of this absorption band depends on the size and shape of the Ag NPs, which arise from the collective oscillations of the free conduction band electrons induced by the incident electromagnetic radiation.…”

Preparation of silver and copper nanoparticles in presence of ascorbic acid and investigation of their antibacterial activity

“…1, silver colloidal dispersion has intense absorption band, due to the surface plasmon resonance, with a maximum at 387 nm. The shape of the absorption band suggests that Ag NPs are spherical (Laban et al, 2013;Laban et al, 2014;Laban et al, 2015;Laban et al, 2016). The presence of gelatin ( Fig.…”

An Insight into the Efficient Dimethoate Adsorption on Graphene-Based Materials—A Combined Experimental and DFT Study

“…Several experiments were performed to elucidate the reaction mechanism of DMT interaction with IG and GO surfaces. Here, we used the approximation of the bimolecular interaction between biological macromolecules and the ligand, considering DMT as the ligand and adsorbents as macromolecules (receptors) with several binding sites [36,37]. The DMT molecule was regarded as the box with the dimensions 10 × 3 × 3 nm.…”

“…The results were analyzed in parallel by applying the Scatchard model to study the binding mode and estimate the binding parameters according to Equation (4) and Equation ( 5): In the case of random binding, Equation ( 4) should be the straight line, since cooperative binding results in a humped curve, which rises to a maximum and then declines to 0 with the intercept at x-axis equal to , i.e., the total concentration of occupied BS per mol of the macromolecule surface. Equation ( 5) represents the modified Hill plot [36,37].…”

“…In the case of random binding, Equation ( 4) should be the straight line, since cooperative binding results in a humped curve, which rises to a maximum and then declines to 0 with the intercept at x-axis equal to N, i.e., the total concentration of occupied BS per mol of the macromolecule surface. Equation ( 5) represents the modified Hill plot [36,37]. Here, K ads is the ligand-macromolecule association constant.…”