Conductometric Studies Research Articles

The correlation properties of chitosan in dimethyl sulfoxide + acid by conductometric study

ABSTRACT The present work is concerned with experimental results of conductometric properties of Biopolymer of chitosan solutions in HCl acid and dimethyl sulphoxide DMSO. The electrical conductivity of solutions of Chitosan CH + DMSO/HCl over a wide range of concentrations and at different temperatures was measured. The reduced electrical conductivity and the activation energy of reduced electrical conductivity are calculated. Biopolymers solutions exhibit a critical concentration c*, separating dilute solutions into dilute solutions and semi dilute solutions. The most important results refer to the activation energy of reduced electrical conductivity found from Arrhenius plots. The dependence of the activation energy on solution concentration and temperature is discussed. The biopolymer CH behaviour can be extrapolated from the Flory-Huggins theory by decomposing such as . The dilute solution behaviour of Arrhenius is described by the CH-DMSO/HCL interaction and represented by the function . For the semi – dilute solution behaviour of non-Arrhenius which is described by the interaction between the CH-CH and DMSO/HCL-DMSO/HCL and represented by the function .

Spectrophotometric and conductometric studies on the interaction of surfactant with polyelectrolyte in the presence of dye in aqueous medium

The concentration of methyl red (MR) dye has a significant influence on how the CTAB + NaPSS complex (CTAPSS) aggregates and sticks together. However, the effect of MR dye on CTAPSS has not yet been thoroughly investigated. The major goal of this work is to use conductometry and UV–Vis. techniques to investigate the influence of MR on the interactions between a cationic surfactant, cetyltrimethylammonium bromide (CTAB) and an anionic polyelectrolyte, sodium polystyrene sulfonate (NaPSS) in aqueous environments. By observing changes in the dye's spectra and the breaking points of conductometric curves, it is obvious that MR causes the development of surfactant aggregates. Critical aggregation concentration (CAC), apparent critical micelle concentration (CMC*), ionization degree (α), binding constant, and various other important thermodynamic parameters were determined by conductivity techniques at 298.15 ± 0.2 K. The CAC and CMC* values dropped on raising the concentration of CTAB with MR in the CTAB + NaPSS + MR system, which is caused by the substantial electrostatic interactions between CTAB/NaPSS and MR. With anionic MR, aggregation and micellization become easier, as seen by hypsochromic shift and reduction in the absorption band's intensity. With increasing CTAB concentrations, the absorption spectra of MR were observed between 430 and 440 nm for the basic form steadily dropped to 414–421 nm. The Benesi-Hildebrand equation was used to calculate the binding constants from the absorption spectra of MR. The CMC of CTAB in water was determined to be 0.00091 molL-1 but the CMC* of CTAB for the CTAB + NaPSS system was determined to be 0.001438 molL-1 and CMC* for the CTAB + NaPSS + MR system was observed to be 0.001328 molL-1 by conductivity and 0.001310 molL-1 by UV–Vis. spectroscopy at 298.15 ± 0.2 K. Also, it is observed that CMC* obtained by spectroscopy is slightly lower (0.001310 mol L-1) than those obtained from conductometry (0.001328 mol L-1) since the spectrum is extremely sensitive for molecular interactions and their properties.

A UV–visible and conductometric studies on the analyses of valine and ninhydrin reaction in aqueous-surfactant solutions of dicationic geminis (n-s-n type)

The influence of surfactants (represent the respective length of alkyl and tail chain referred to as gemini) was investigated on rate constant (kψ) of valine (Val) and ninhydrin. Also, the effect of other experimental parameters that includes reactant’s concentration (Val and ninhydrin), pH and temperature was performed and examined. Via UV–visible method, the absorbance of different solutions was recorded at fixed time intermissions and kψ was estimated by employing a computer-based procedure. The values ofkψ obtained at varied concentrations of gemini n-s-n (n = 16; s = 4–6) surfactants show an infrequent behavior (plotted askψvs. [gemini]). In the plot, kψ data rises gently at surfactant concentration far smaller related to cmc-value (Segment I) and formerly attains virtually unaffected behavior (Segment II, up to 400 × 10-5 mol dm−3). To end, we perceive a quick variation in kψ beyond 400 × 10-5 mol dm−3 (Segment III). Dicationic geminis improve the study, excellently, at [n-s-n] slighter than cmc over monomeric CTAB. However, quantitative treatment of such results achieved in dicationic gemini surfactant solutions was made by an appropriate model of micellar activity recognized as pseudo phase. Critical micelle concentration (cmc) of dicationic geminis (n-s-n type) with reactants has been determined at two different temperatures 303 K and 353 K using conductometric analysis. A reasonable reaction mechanism concerning the present study is provided. Additionally, some other reaction factors (binding and rate constants) were evaluated and discussed.

Ionic Association of Potassium and Tetrabutylammonium Thiocyanate Salts in Binary Mixtures of γ-Butyrolactone and N,N-Dimethylacetamide at 298.15 K and 308.15 K

Solvation consequences of potassium thiocyanate (KSCN) and tetrabutylammonium thiocyanate (Bu4NSCN) in γ-butyrolactone (GBL), N,N-dimethylacetamide (DMA) and their binary mixtures in concentration range (0.01-0.001) mol Kg–1 of 0, 25, 50, 60, 80 and 100 mol% DMA at T = 298.15 K and 308.15 K have been studied using conductometric study and some samples of KSCN in GBL + DMA binary mixtures of different electrolytic concentrations at ambient conditions studied by FTIR spectroscopic methods. The Shedlovsky equation has been used to elucidate the data in terms of the limiting molar conductances (Λo), ion-pair association constants (KA). The Walden products (Λoηo), solvated radii (ri) and standard free energies of association (ΔGºA) were further evaluated in terms of solvation of ions. The reference electrolyte tetrabutylammonium tetraphenylborate (Bu4NBPh4) was used to determine the limiting molar ionic conductances. In pure solvents and their binary mixtures, electrolytes showed a strong association. The K+ ions have greater solvation in GBL than in DMA observed on basis of solvated radii in GBL + DMA binary solvent mixtures at both experimental temperatures. The study demonstrates that the ion-solvent interactions decrease on enhancing the temperature. The FTIR analysis was applied to obtain information about molecular as well as ionic association of KSCN in GBL + DMA binary mixtures at the ambient conditions, which has provided the information on structuring infrared modes of vibrational stretching frequencies according to the nature of the solvents or the cations. Shifting of vibrational frequencies of several functional groups of DMA and GBL in binary mixed solvents has been observed in terms of ion-ion, ion-solvent and solvent-solvent interactions.

Radiation-Induced Oxidation Reactions of 2-Selenouracil in Aqueous Solutions: Comparison with Sulfur Analog of Uracil.

One-electron oxidation of 2-selenouracil (2-SeU) by hydroxyl (●OH) and azide (●N3) radicals leads to various primary reactive intermediates. Their optical absorption spectra and kinetic characteristics were studied by pulse radiolysis with UV-vis spectrophotometric and conductivity detection and by the density functional theory (DFT) method. The transient absorption spectra recorded in the reactions of ●OH with 2-SeU are dominated by an absorption band with an λmax = 440 nm, the intensity of which depends on the concentration of 2-SeU and pH. Based on the combination of conductometric and DFT studies, the transient absorption band observed both at low and high concentrations of 2-SeU was assigned to the dimeric 2c-3e Se-Se-bonded radical in neutral form (2●). The dimeric radical (2●) is formed in the reaction of a selenyl-type radical (6●) with 2-SeU, and both radicals are in equilibrium with Keq = 1.3 × 104 M−1 at pH 4 (below the pKa of 2-SeU). Similar equilibrium with Keq = 4.4 × 103 M−1 was determined for pH 10 (above the pKa of 2-SeU), which admittedly involves the same radical (6●) but with a dimeric 2c-3e Se-Se bonded radical in anionic form (2●−). In turn, at the lowest concentration of 2-SeU (0.05 mM) and pH 10, the transient absorption spectrum is dominated by an absorption band with an λmax = 390 nm, which was assigned to the ●OH adduct to the double bond at C5 carbon atom (3●) based on DFT calculations. Similar spectral and kinetic features were also observed during the ●N3-induced oxidation of 2-SeU. In principle, our results mostly revealed similarities in one-electron oxidation pathways of 2-SeU and 2-thiouracil (2-TU). The major difference concerns the stability of dimeric radicals with a 2c-3e chalcogen-chalcogen bond in favor of 2-SeU.

Encapsulation of ethyl violet by anionic-cationic mixed micellar solution: Spectroscopic and conductometric studies

Organic dyes are extensively used in various industries i.e. textile. Their hydrophobicity is the main bottleneck in their applications, where the dispersion medium is water. The poor solubility of such colorants is addressed by the addition of different surfactants, but none of the single surfactants proved fully satisfactory so far. Herein, different formulations of anionic and cationic surfactants (SDS, SDBS, CTAB, and TTAB) have been employed to enhance the solubility and stability of a cationic dye, ethyl violet (EV). Spectrophotometric data helped to calculate the values of the partition coefficient (K x ), binding constant (K b ), and Gibbs energies of respective processes. The said parameters are indicators of the degree of solubilization which were calculated at 298.15 K. The data of specific conductance was utilized to estimate critical micelle concentration (CMC) and to calculate thermodynamic parameters; Gibbs energy (ΔG m ), entropy (ΔS m ), and enthalpy (ΔH m ) of micellization for surfactants in the presence of dye at different temperatures (303.15–318.15 K). The obtained results from both techniques revealed the spontaneous nature of micellization and solubilization. Furthermore, the binding and partitioning ability of mixed micellar media came out to be significantly different than that of the solo surfactant system due to the synergistic effect of cationics on micellar media of anionics. It shows how dye is lying inside the SDS and SDBS micelle. • Locus of incorporated dye is near water-micelle interface. • Charge density of a micelle governs its solubilizing efficacy. • Mixing of different surfactants has a synergistic effect on solubilizing power.

Conductometric studies of 1, 3, 5 –triazinothiocarbamide at different concentration and temperature

Conductometric studies of 1, 3, 5 –triazinothiocarbamide at different concentration and temperature

Conductometric studies of 1, 3, 5 –triazinothiocarbamide at different concentration and temperature

Conductivity plays vital role in drug diffusion. Thermodynamic parameters affected by substituents of drug. Thermodynamic parameters of 1, 3, 5 –triazinothiocarbamide (1a) have been investigated by using conductometrically carried out at different molar concentrations. This work highlights investigation of G, K and µ values. The thermodynamic parameters viz. ΔH, ΔS and ∆G for ion pair formation determine from the value of ion association constant. This technique is suitable and accurate to study of pharmokinetics and pharmodynamics parameters.

Spectrophotometric and conductometric studies of new synthesized azo derived from pyrazole as analytical reagents

Spectrophotometric and conductometric studies of new synthesized azo derived from pyrazole as analytical reagents

Conductometric Study of Proline-Mn (II) Complex in Some Solvents at Various Temperatures, with Computational Factors Calculation

The equivalent conductivities of proline in water, methanol were studied in the temperature range of 288.15 to 313.15 K at 5 K intervals, in mixtures of methanol and water at percentages of 10 %, 20%, 30%, 40% and, 50% of methanol at 37°C. The experimental data were treated by the Lee-Wheaton conductivity equation of unsymmetrical electrolytes (1:2) (1 molecule of metal with 2 molecules of ligand) derived to calculate the conductivity parameters, equivalent conductance at infinite dilution Λₒ, ionic conductivity, association constant Ka and the main distance between ions in solution( R) at best fit values of (6Λ). Thermodynamic quantities for the ion-association reaction ΔG°, Δङ° and ΔS°) have been also measured. The results of the analysis showed that the ions of the complex can be separated by solvent molecules (SSIP). The values of Ka, Λ° and R were found to be different from one solvent to another depending on the interactions in the solution. Furthermore, the chemical structure of the Proline-Mn complex was optimized by using of Gaussian interface version 16.0 program of chem3D to optimiz the features of complex molecule. The suggested statistical model possesses only two parameters with excellent values of the square regression coefficient (r2) and cross-validation (q2) are equal to 0.999 and 0.994, respectively, which refers to the perfect relationship between Ka value and the physical properties of the solvent.

Elucidation for coordination features of hydrazide ligand under influence of variable anions in bivalent transition metal salts; green synthesis, biological activity confirmed by in-silico approaches

Synthesis of new N′- cyclohexylidene-3‑hydroxy-2-naphthohydrazide (H2L) complexes was carried out by ball milling technique in the lack of solvent (green approach) and then characterized by analytical and spectroscopic techniques. The metal salts used for preparations, were varied in their conjugated anions (Cl−, SO4−2 & OAc−) to investigate the changes in properties of obtained complexes, by changing anions, even with the same ligand. The ligand was coordinated mainly as monobasic with the metal acetate salts, while a neutral with metal chloride or sulfate salts. Such coordination modes were appeared through bidentate or tridentate towards central metals within different molar ratios (1: 1 or 1:2, M:L). Conductometric study was performed for Co(II) complex to estimate the complex stoichiometry and either formation or association constants, in solution state. DMOL3 program was used via DFT/B3LYP method to optimize the studied compounds and to obtain essential quantum parameters. Consequently, we confirmed the coordination of O(11), O(13) and N(16) atoms according to their features appeared in molecular modeling study. In-silico assessment was performed to examine the interaction features of new compounds with pathogenic-DNA, before in-vitro screening. Such assessment was carried out firstly by pharmacophore query within MolPort drug-library to discover the analogues drugs in activity towards DNA proteins. MolPort-007–588–377 and MolPort -000–734–772 were the code numbers of two analogues drugs. Secondly MOE-docking process was executed to explain all interaction features and rank the inhibition activity of complexes. Furthermore, antimicrobial, antioxidant and antitumor activity were investigated for all compounds and Ni(II)-Bis(HL) complex showed excellent antioxidant activity. Whereas, Co(II)-Bis(HL) complex showed excellent cytotoxicity towards liver cancer cells. Finally, the whole characteristics of complexes were changed by changing conjugated anions, even with the same ligand.

Interaction of sulphone based reactive dyes with cationic surfactant: a spectroscopic and conductometric study

Abstract Interaction of sulphone based reactive dyes, designated as dye-1 and dye-2, with cationic micellar system of cetyltrimethylammonium bromide (CTAB), has been investigated by spectroscopic and conductometeric measurements. Efficiency of the selected micellar systems is assessed by the values of binding constant (K b ), partition coefficient (K x ) and respective Gibbs energies. Critical micelle concentration (CMC) of surfactant, electrostatic and hydrophobic interactions as well as polarity of the medium plays significant role in this phenomenon. The negative values of Gibbs energies of binding (∆G b ) and partition (∆G p ) predicts the feasibility and spontaneity of respective processes. Similarly negative values of ∆G m and ∆H m and positive values of ∆S m , calculated from conductometeric data, further, revealed the exothermicity, spontaneity and, thus, stability of system. The results, herein, have disclosed the strong interaction between dye and surfactant molecules. The dye-2 has been observed to be solubilized to greater extent, as compared to dye 1, due to strong interaction ith hydrophiles of CTAB and accommodation of its molecules in palisade layer of micelle closer to the micelle/water interface.

Role of mixed micellar media to enhance solubilization of Allura Red: differential spectroscopic and conductometric study

The reported work is an attempt to explore the most appropriate micellar media for the solubilization of organic dye, Allura Red (AR). The micellar solution of anionic surfactant i.e. sodium dodecyl sulphate, SDS and mixed micellar solutions of SDS and cetyltrimethylammonium bromide, CTAB (cationic surfactant) have been employed for said purpose. The values of partition coefficient, K x and Gibbs free energy change of partition, ΔG p decide the suitable composition of surfactant solution with the highest solubilizing power. The said parameters have been determined from data of UV/Visible spectroscopy while thermodynamic parameters (ΔG m, ΔH m and ΔS m) have been calculated from specific conductivity data. The effect of the presence of various concentrations of CTAB i.e. 0.1, 0.2 and 0.4 mM has been observed to find the most suitable concentration of CTAB that produces a maximum increase in the solubilizing capacity of SDS solution.

ELECTROCHEMICAL PROPERTIES OF AQUEOUS SOLUTIONS OF SODIUM AMINOMETHANESULFONATES

The pH and conductometric study of the electrochemical properties of aqueous solutions (1∙10-4 ÷ 9∙10-3 М) YNHCH2SO3Na (Y = H, CH3, HOCH2CH2, (CH3)3C and C6H5CH2) was carried out. The values of the limiting electrical conductivity were calculated by extrapolation according to Shidlovsky. The activation parameters of the electrical conductivity of the systems “sodium aminomethanesulfonate – H2O” at 293-313 K were obtained.

A Conductometric Study of Complexation Reactions between Kryptofix5 with Al3+, Fe3+, Cu2+, and Ca2+ Metal Cations in Acetonitrile–Ethanol Binary Solvent Solutions

In the current study, the results of the conductometric work of the complexation reaction of Kryptofix5 (Scheme 1) with Al3+, Cu2+, Ca2+, and Fe3+ cations are studied in acetonitrile–ethanol (AN–EtOH) binary non-aqueous solvents. In all cases, the achieved results reveal that the stoichiometry of the complexes formed between the ligand and Al3+, Cu2+, Ca2+, and Fe3+ metal cations is 1 : 1 [ML] complex. GENPLOT (the computer program) calculates the stability constants of complexes of (Kryptofix5 · M)n+. The selectivity order of Kryptofix5 ligand for the studied metal cations in pure AN and AN–EtOH (AN = 50 mol % ) binary mixed solvent at 15°C is found to be Ca2+ > Fe3+ > Cu2+ > Al3+ and Cu2+ > Fe3+ > Ca2+ > Al3+, respectively. As a result, the selectivity order of the ligand for the metal cations shows independence from the nature and composition of the mixed binary solvent. By using the Van’t Hoff plots, the thermodynamic parameters ( $$\Delta H_{{\text{c}}}^{^\circ }$$ , $$\Delta S_{{\text{c}}}^{^\circ }$$ ) value for 1 : 1 complexes are calculated from the temperature due to the stability constants of the complexes. The achieved findings reveal that the thermodynamics of the complexation reaction is affected by the nature and composition of the mixed solvents, and the complexation processes entropy and enthalpy are stabilized in most cases.

Conductometric Study of Complexation of Macrocyclic Compounds with Zinc(II) and Copper(II) Ions in Aqueous-Organic Solvent Mixtures

The conductance behavior of Zn2+ and Cu2+ and their complexes with two ligands (crown ethers) have been inspected in 10, 20, 30, and 40% DMF–water mixed solvent at 298.15, 308.15, 318.15, and 328.15 K. The conductance study indicates a 1 : 1 complexation mode amongst the metal ions and ligands hereby studied. The order of stability constants with crown ethers was found to be Cu(II) > Zn(II). The stability constant for Zn2+ ion with crown ether complexes in 10 and 40 wt % solvent composition varies in the order of benzo-18-crown-6 > benzo-15-crown-5. The stability constant for Cu2+ ion with crown ether complexes in 10% solvent composition varies in the order of benzo-18-crown-6 > benzo-15-crown-5, and for 40% solvent composition, it is benzo-18-crown-6 > benzo-15-crown-5. The enthalpy and the entropy of complexation were estimated from the variation of stability constants with respect to the variation of temperature. The observed results elicit that the complexation is enthalpy stabilized, but entropy destabilized.

A Conductometric study of complexation reaction between dibenzyl-14-crown-4, with ZrO2+ in some binary mixed nonaqueous solvents

In Some binary methanol mixtures, (MeOH), 1,2 dichloroethane (DCE), acetonitrile (AN), and tetrahydrofuran (THF), with dimethylformamide (DMF) at different temperatures using the conductometric process, the reaction of macrocyclic ligand to complexation, dibenzyl-14-crown-4 (DB14C4) with ZrO2+ cation was examined. The conductance data show that in all solvent systems, the stoichiometry of the complex formed between (DB14C4) and ZrO2+ cation is 1:1 (M:L). The stability order of (DB 14C4.ZrO)2+complex in pure non-aqueous solvents was found to be: [AN], [DCE], [MeOH], [THF], [DMF]. A non-linear behaviour was observed improvements in log Kf of (DB14C4.ZrO)2+ complex or Binary mixed solvent composition, It Was clarified as to the Interactions with solvents and even solvents in terms of the hetero-selective solving of the ecosystem affected by complexation response. The obtained results show that the stability of (DB14C4.ZrO)2+ complex is sensitive to the composition of the mixed solvent. The values of thermodynamic parameters ΔH°cand ΔS°c) for the formation of (DB14C4.ZrO)2+complex using van’t Hoff maps, the stability constant was obtained from temperature dependence. The results show that in most cases, the (DB 14C4.ZrO)2+complex is enthalpy destabilized but entropy balanced and the values and signs of thermodynamic parameters are often These are decided by nature and composition of the mixed solvents.

Role of carbonate electrolytes on interaction of quinolone drug with anionic surfactant at various temperatures: A conductometric study

AbstractThe role of different carbonate salts on the interaction of anionic surfactant sodium dodecyl sulfate (SDS) with employed quinolone antibiotic drug (ciprofloxacin hydrochloride [CFH]) was explosively inspected through measuring specific conductivity (κ) of the investigated system. The drug, CFH, is an excellent antibiotic for the treatment of different bacterial infections like skin, urinary tract, and respiratory infections. The estimated critical micelle concentrations (cmc) of SDS were observed to be dwindled in the attendance of electrolytes and cmc reduction continues with the escalation of the electrolyte's concentration. The magnitudes of cmc for the SDS + CFH mixture were reduced with the elevation of temperature in K2CO3 and CaCO3 medium while increased with the rise of the temperature in the Na2CO3 medium. The magnitudes of counterion binding to micelles (β) were increased with the increase of the concentration of Na2CO3 and K2CO3 up to definite value and then reduced with the increase of successive rise of concentration of both salts at all temperatures while decreased monotonically with the rise of electrolyte concentration in CaCO3 medium. The values of standard free energy ( ) were achieved to be negative in each case suggesting spontaneous self‐assembly formation. The standard entropy change ( ) along with enthalpy change ( ) was also assessed and discussed elaborately.

CONDUCTOMETRIC STUDY OF LIGAND STRUCTURE INFLUENCE ON THE Pb(II) COMPLEXATION WITH CROWN ETHERS

The conductometric study of ligand structure influence on the Pb(II) complexation with crown ethers in different solvents has been investigated. In this paper, the complexation reaction of macrocyclic ligand, 18-crown-6 (18C6), dibenzo-18-crown-6 (DB18C6), and Pb(II) cation was studied in different solvents: dichloromethane (DCM) and 1,2- dichloroethane (1,2-DCE). The effects of surfactant structure (Triton X-100 and Triton X-45) on the conductivity of the Pb(II) complex with 18-crown-6 and dibenzo-18-crown-6 ether have been investigated. The conductance data showed that the stoichiometry of the complexes in most cases is 1:1(ML). It is also demonstrated that the influence of crown ethers is deeply affected by the organic solvent used. In the solvents studied, the stability of the resulting complexes showed higher stability in dichloromethane comparing with 1,2- dichloroethane. Macrocyclic ligand 18-crown-6 showed more suitable for complexation of Pb(II) ions compared to dibenzo-18-crown-6. Adding a surfactant affected the higher absolute values of the conductivity of systems, but not the change in the stoichiometric ratio between a metal ion and macrocyclic ligand.

Study of Quinizarin Interaction with SDS Micelles as a Model System for Biological Membranes

Investigation of the interaction of quinizarin (Q), an analogue of the core unit of different anticancer drugs, with anionic SDS micelles has been performed by absorption and conductance measurements in 0.1 M phosphate buffer, pH 7.4 and over the temperature range of 298.15-323.15 K. The values of binding constant (Kb), partition coefficient (Kx) and the corresponding thermodynamic parameters (Gibbs free energy, enthalpy, entropy) for the binding and distribution of quinizarin between the bulk aqueous solution and surfactant micelles have been determined and discussed in terms of possible intermolecular interactions. Values of critical micelle concentration (CMC) and degree of ionization (?) for SDS in the absence and the presence of quinizarin have been evaluated from conductometric study. Comparing the absorption spectra of quinizarin in SDS micelles with the spectra in different solvents revealed that quinizarin molecules are located in the hydrophilic region of SDS micelles. The trend of changes in Gibbs free energy, enthalpy and entropy with temperature shows that both binding and partition processes are spontaneous and entropy driven. In addition, the hydrophobic interactions are the main forces involved in binding and partition processes.