Acceleration of diffusion in ethylammonium nitrate ionic liquid confined between parallel glass plates

The bulk self diffusion of the ethylammonium cation and the nitrate anion can both be described by respective single diffusion coefficients. Diffusion of the anion is 1.7 times higher than that of the cation. This indicates no tight association of the ions in the ionic liquid. For the ethylammonium cation confined between glass plates the effective diffusion coefficient along, as well as normal to the confining glass plates is higher by a factor of 1.86 as compared to that in the bulk. The same time, NMR T2 relaxation of protons of NH3 group of the EA cation is faster by a factor of 22 than that in bulk. 2H NMR spectra of selectively labeled CH2 and CH3 groups of EA do not demonstrate any ordering of the EA between the glass plates. We suggested that these data favor a model where a bulk isotropic sponge like structure of EAN is saved in the confinement, but sizes of connecting channels increases. Those leads to faster translational diffusion and faster exchange processes of protons of NH3 group, in comparison with the bulk.Comment: 11 pages, 5 figures, 1 tabl

Structural and Ion Dynamics in Fluorine-Free Oligoether Carboxylate Ionic Liquid-Based Electrolytes

Here, we investigate the physicochemical and electrochemical properties of fluorine-free ionic liquid (IL)-based electrolytes with two different cations, tetrabutylphosphonium, (P-4,4,4,(4))(+), and tetrabutylammonium, (N-4,N-4,N-4,N-4)(+), coupled to a new anion, 2-[2-(2-methoxyethoxy)ethoxylacetate anion (MEEA), for both neat and (P-4,P-4,P-4,P-4) (MEEA)(-), also doped with 10-40 mol % of Li(MEEA). We find relatively weaker cation-anion interactions in (P-4,P-4,P-4,P-4)(MEEA) than in (N-4,N-4,N-4,N-4)(MEEA), and for both ILs, the structural flexibility of the oligoether functionality in the anion results in low glass transition temperatures, also for the electrolytes made. The pulsed field gradient nuclear magnetic resonance (PFG NMR) data suggest faster diffusion of the (MEEA)(-) anion than (P-4,P-4,P-4,P-4)(+) cation in the neat IL, but the addition of a Li salt results in slightly lower mobility of the former than the latter and lower ionic conductivity. This agrees with the combined Li-7 NMR and attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy data, which unambiguously reveal preferential interactions between the lithium cations and the carboxylate groups of the IL anions, which also increased as a function of the lithium salt concentration. In total, these systems provide a stepping stone for further design of fluorine-free and low glass transition temperature IL-based electrolytes and also stress how crucial it is to control the strength of ion-ion interactions

Nontoxic antimicrobial micellar systems based on mono- and di-cationic Dabco-surfactants and furazolidone: Structure-solubilization properties relationships

Supplementary data to this article can be found online at https://doi.org/10.1016/j.molliq.2019.112062.Self-assembly and solubilization properties of amphiphilic mono- and bisquaternized derivatives of 1,4-diazabicyclo[2.2.2]octane (mono-CS-n and di-CS-n, where CS cationic surfactant, n=12, 14, 16, 18) was investigated by nuclear magnetic resonance with magnetic field pulse gradient. The influence of Dabco-surfactant structure (head group and length of alkyl chains) on critical micelle concentration and aggregation number of micelles was studied. The CMC of mono-CS-n are lower than CMC of di-CS-n. The aggregation numbers of mono-CS-n micelles are higher than for di-CS-n micelles. The solubilization capacity of mono-CS-n is higher than di-CS-n. The solubilization capacity of mono-CS-16 is 2.5 times higher than CTAB in the case of Orange OT as a solute, and it is close to CTAB in the case of Sudan I. The solubility of a poorly water-soluble antibacterial drug furazolidone was improved by micellar solubilization based on mono- and di-Dabco-surfactants. Mono-CS-n is the best solubilizing agents toward furazolidone. The use of mixed composition mono-Dabco-16-furazolidone provides a significant increase in antimicrobial activity (2 times against bacteria and 8 times against fungi) and reduces 2 times the dose of each of the components in combination formulation and causes <2% haemolysis of human red blood cells at the active dose.The report study was funded by Russian Foundation for Basic Research according to the research project № 18-43-160015. The authors gratefully acknowledge the CSF-SAC FRC KSC RAS.info:eu-repo/semantics/publishedVersio

Molecular self-diffusion and micellar structure in the aqueous solutions of AF9-10 ethoxylated isononylphenol near a cloud point

Sizes of micelles and compositions of aggregates in the aqueous solutions of the nonionic surfactant oxyethylated monoalkyl phenol (neonol AF9-10) were determined by NMR spectroscopy, NMR diffusometry and dynamic light scattering in a wide range of tem- peratures near the cloud point. The cloud point extraction of phenol from aqueous solutions by the surfactant AF9-10 was performed

Composite Polyvinylpyrrolidone–Sodium Alginate—Hydroxyapatite Hydrogel Films for Bone Repair and Wound Dressings Applications

Today, the synthesis of biocompatible and bioresorbable composite materials such as “polymer matrix-mineral constituent,” which stimulate the natural growth of living tissues and the restoration of damaged parts of the body, is one of the challenging problems in regenerative medicine. In this study, composite films of bioresorbable polymers of polyvinylpyrrolidone (PVP) and sodium alginate (SA) with hydroxyapatite (HA) were obtained. HA was introduced by two different methods. In one of them, it was synthesized in situ in a solution of polymer mixture, and in another one, it was added ex situ. Phase composition, microstructure, swelling properties and biocompatibility of films were investigated. The crosslinked composite PVP-SA-HA films exhibit hydrogel swelling characteristics, increasing three times in mass after immersion in a saline solution. It was found that composite PVP-SA-HA hydrogel films containing HA synthesized in situ exhibited acute cytotoxicity, associated with the presence of HA synthesis reaction byproducts—ammonia and ammonium nitrate. On the other hand, the films with HA added ex situ promoted the viability of dental pulp stem cells compared to the films containing only a polymer PVP-SA blend. The developed composite hydrogel films are recommended for such applications, such as membranes in osteoplastic surgery and wound dressing

<i>N</i>,<i>N</i>‑Dimethyldodecylamine Oxide Self-Organization in the Presence of Lanthanide Ions in Aqueous and Aqueous-Decanol Solutions

The article represents the results of research in self-organization of new lanthanide systems in water–decanol medium. The systems are based on <i>N</i>,<i>N</i>-dimethyldodecylamine oxide, a zwitterionic surfactant. The study covers the complex formation of lanthanide ions with C₁₂DMAO molecules and the influence of Ln­(III) ions and medium composition on surfactant association in diluted solutions. The analysis of adsorption isotherms was carried out on the basis of the combination of Gibbs and Langmuir adsorption equations. The results were used to determine physicochemical properties and parameters of a monomolecular adsorption layer. The research objects were various lanthanide ions with identical coordination centers. A number of spectroscopic methods (UV, NMR self-diffusion, EPR, dynamic light scattering (DLS), and fluorescent analysis) were involved in the research for comparative estimations of molecular dynamics, critical micellization concentration, geometry, sizes, and aggregation numbers of micellar aggregates. Micelle structure simulation revealed good agreement between experimental data and quantum chemical calculations

Anticancer Potential of Pyridoxine-Based Doxorubicin Derivatives: An In Vitro Study

Doxorubicin (DOX) is a prevalent anticancer agent; however, it is unfortunately characterized by high cardiotoxicity, myelosuppression, and multiple other side effects. To overcome DOX limitations, two novel pyridoxine-derived doxorubicin derivatives were synthesized (DOX-1 and DOX-2). In the present study, their antitumor activity and mechanism of action were investigated. Of these two compounds, DOX-2, in which the pyridoxine fragment is attached to the doxorubicin molecule via a C3 linker, revealed higher selectivity against specific cancer cell types compared to doxorubicin and a promising safety profile for conditionally normal cells. However, the compound with a C1 linker (DOX-1) was not characterized by selectivity of antitumor action. It was revealed that DOX-2 obstructs cell cycle progression, induces apoptosis via the mitochondrial pathway without the development of necrosis, and showcases antioxidant capabilities, underlining its cell-regulatory roles. In contrast to doxorubicin’s DNA-centric mechanism, DOX-2 does not interact with nuclear DNA. Given these findings, DOX-2 presents a new promising direction in cancer therapeutics, which is deserving of further in vivo exploration