Solvent Phase Research Articles

FACS‐Sortable Triple Emulsion Picoreactors for Screening Reactions in Biphasic Environments

AbstractBiphasic environments can enable successful chemical reactions where any single solvent results in poor substrate solubility or poor catalyst reactivity. For screening biphasic reactions at high throughput, a platform based on microfluidic double emulsions can use widely available FACS (Fluorescence Activated Cell Sorting) machines to screen millions of picoliter reactors in a few hours. However, encapsulating biphasic reactions within double emulsions to form FACS‐sortable droplet picoreactors requires optimized solvent phases and surfactants to produce triple emulsion droplets that are stable over multi‐hour assays and compatible with desired reaction conditions. This work demonstrates such FACS‐sortable triple emulsion picoreactors with a fluorocarbon shell and biphasic octanol‐in‐water core. First, surfactants are screened to stabilize octanol‐in‐water emulsions for the picoreactor core. With these optimized conditions, stable triple emulsion picoreactors (>70% of droplets survived to 24 hr), produced protein in the biphasic core via cell‐free protein synthesis are generated, and sorted these triple emulsions based on fluorescence using a commercial FACS sorter at >100 Hz with 75–80% of droplets recovered. Finally, an in‐droplet lipase assay with a fluorogenic resorufin substrate that partitions into octanol is demonstrated. These triple emulsion picoreactors have the potential for future screening bead‐encoded catalyst libraries, including enzymes such as lipases for biofuel production.

Computational Investigation of Pristine, Al-, and Ga-Doped Zn12O12 nanoclusters as Detection Platforms for Methadone in gas and solvent phases

Electrochemical sensors are emerging as promising tools for point-of-care diagnostic medical devices, benefiting from advancements in nanomaterials. These nanomaterials enable the development of smaller, more sensitive, and selective sensors while reducing fabrication and maintenance costs. This work presents a comprehensive theoretical investigation of the potential application of pristine, Ga- and Al-doped Zn12O12 nanoclusters for detecting methadone, a critical analyte in various medical and law enforcement applications. Employing density functional theory (DFT) calculations at the B3LYP-D level with the 6-311G (d, p) basis set, we have elucidated the interactions between these nanoclusters and methadone. The results reveal that methadone exhibits intense adsorption energies of -41.02, -39.79, and -59.77 kcal/mol on the pristine Zn12O12, GaZn11O12, and AlZn11O12 nanoclusters, respectively, in their most stable configurations. The doped nanoclusters, GaZn11O12 and AlZn11O12, displayed significant gap energies (Eg) changes upon methadone adsorption, indicating enhanced sensitivity towards this analyte. The UV-Vis spectroscopic analysis showed that methadone adsorption on the GaZn11O12 and AlZn11O12 nanoclusters led to distinct spectral shifts and oscillator strength variations compared to the Zn12O12 nanocluster. The transition theory calculations highlighted the GaZn11O12 nanocluster's short recovery time of 0.44 seconds, a crucial attribute for practical applications. Solvent effect studies demonstrated the stability of the methadone/GaZn11O12 complex in water and revealed its heightened polarization, as evidenced by the increased dipole moment. These findings suggest that the GaZn11O12 nanocluster is a promising candidate for detecting methadone in gas and liquid phases, with favorable attributes such as high sensitivity, rapid reversibility, and stability in gas and aqueous environments. Thus, this nanocluster can be used in sensor devices.

Exploration of the potential energy surfaces of the [formula omitted] clusters: Solvent phase vs gas phase

In the present work, we investigated the potential energy surfaces (PESs) of the structures of the Cu2+ ion in methanol clusters in two different media: gas and solvent phases. The effects of medium polarization by the integral equation formalism polarized continuum model (IEF-PCM) on structural and energetic parameters were examined on the conformers of the Cu2+(MeOH)n=9,10 clusters using the M06-2X/6-31++G(d,p) level of theory. Thus, in the solvent phase, the cluster structures are hexa-coordinated in the global minimum isomer. The study of the temperature dependency shows that the hexa-, and penta-coordinated structures compete with a large predominance of the hexa-coordinate structures with two solvation shells in the solvent phase. The Wiberg bond indices (WBI) analysis of the ionic bond confirms the structural study. In the IEF-PCM solvent compared to the gas medium, Wiberg bond indices of the tetra-, and penta-coordinate conformers are weaker, and the hexa-coordinate conformers in both media are nearly identical. This proves that compared to the solvent phase, the dative bond is stronger in the gas phase. This is supported by the significant difference in the electronic binding energies at saturation found with a single fitting function which are -88.6 and -146.6 kJmol−1 in the solvent and gas phases, respectively.

Application of quality by design in the development of HPTLC Method for the estimation of ceritinib in bulk and synthetic mixture

The aim of the present work is to develop and validate the High-Performance Thin Layar Chromatography method for the estimation of Ceritinib in bulk and synthetic mixture using the Analytical Quality by Design (AQbD) approach as per ICH Q8 (R2). The AQbD is used to develop a precise HPTLC method. The AQbD parameter elements like QTMP (Quality Target Method Profile- Ceritinib, method type, instrument requirement, sample characteristics, synthetic mixture preparation) CMA—Critical method attributes (chloroform ± 1 ml, methanol ± 1 ml, triethylamine ± 0.05), and Risk assessment (the Ishikawa (fishbone) diagram) were carried out for the development of the HPTLC method for Cerinitib. The Box-Behnken design was utilized for the optimization of chromatographic conditions in HPTLC. The method utilized an aluminum HPTLC plate pre-coated with silica gel G60 F254 as a stationary phase along with chloroform: methanol: triethylamine (8.9: 1.6: 0.07 v/v/v) as a mobile phase. ANOVA results and perturbation plot indicates that methanol and triethylamine had more impact than chloroform on the retardation factor. The retardation factor was found to be 0.37. The absorbance mode at 277 nm was used for the densitometric study. It was found that the linearity ranged from 20 to 100 ng/band, with a correlation coefficient of 0.998. No interference was observed from excipients and mobile phase solvents. The results indicate that the AQbD approach is effectively applied to optimize the retardation factor and the method is appropriate for routine laboratory analysis.

Pristine B40 fullerene as a potential gemcitabine drug carrier for anti-lung cancer properties: a DFT and QTAIM study

Novel biomedical applications of various nanomaterials are being extensively researched as drug delivery systems. These nanomaterials deliver various anticancer treatments into the specific tumor cell sites, which reduces their terrible side effects. In this study, we have used DFT/B3LYP/6-311++G(d,p) level of theory to examine the efficacy of the pristine B40 fullerene (Boron) as a drug delivery vehicle for gemcitabine an anti-lung cancer medication at various position. From our investigation the most stable adsorption orientation was observed between double bonded oxygen atom of the drug and six membered ring boron atoms of B40 fullerene both in gas and solvent phases. The frontier molecular orbitals and QTAIM studies further support the interaction of gemcitabine medication with the B40 fullerene. NBO and MEP methods show substantial charge transfer from gemcitabine drug molecules to the fullerene. Overall, the results suggest that the B40 fullerene effectively adsorbs the drug and hence can be used as a tool for drug delivery system.

Modulating phase segregation during spin-casting of fullerene-based polymer solar-cell thin films upon minor addition of a high-boiling co-solvent

The impact of additives on the nanoscale structures of spin-cast polymer composite films, particularly in polymer solar cells, is a topic of significant interest. This study focuses on the blend film comprising poly(thieno[3,4-b]thiophene-alt-benzodithiophene) (PTB7) and [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM), exploring how additives like 1,8-diiodooctane (DIO) influence the film structures spin-cast from chlorobenzene solution. Combined results of specular X-ray and neutron reflectivity, grazing-incidence small- and wide-angle X-ray scattering (GISAXS and GIWAXS), and X-ray photoelectron spectroscopy indicate that DIO could significantly enhance the dispersion of PC71BM and reduce composition inhomogeneity in the film. Time-resolved GISAXS–GIWAXS with 100 ms resolution further captures a rapid spinodal decomposition of the mixture within 1 s in the constant-evaporation stage of spin-casting. Further combined with parallel analysis of time-resolved UV–Vis reflectance, these findings reveal that DIO mitigates the spinodal decomposition process by accelerating solvent evaporation, which, in turn, decelerates phase segregation, leading to a nucleation-driven process. These observations provide mechanistic insights into the role of additives in controlling the nanostructural evolution of spin-cast films by altering the kinetics of solvent evaporation and phase separation during the spin-coating process.

End Group Effects on Anion Binding in Tetraglycine Peptide: A Computational Study.

The importance of anions in various processes has led to a search for molecules that can effectively recognize and interact with these anions. This study explores how the tetraglycine [(Gly)4] peptide in its zwitterionic, neutral, and terminally capped forms acts as a receptor for H2PO4 - and HSO4 - anions within the framework of supramolecular host-guest chemistry. Using molecular dynamics (MD) simulations, we obtained the conformations of the receptor-anion complexes. Density functional theory (DFT), quantifies the complexes' interaction energies in both gas and solvent phases. Proton transfer within the zwitterionic complex with H2PO4 - anion alters peptide charge distribution, affecting its conformation and binding site arrangement, as analysed by quantum mechanics/molecular mechanics (QM/MM) methods. Symmetry-adapted perturbation theory (SAPT) and noncovalent interactions analysis highlight the role of electrostatic interactions in these receptor-anion complexes. It emphasizes the key interactions such as N-H⋅⋅⋅⋅O and O-H⋅⋅⋅O=C between the peptide backbone and anions and elucidates the molecular recognition mechanism driven by crucial noncovalent interactions. The termination of the peptide's end groups modulates anion binding sites from the backbone to the charged N-terminal, resulting in distinct binding sites. Our findings provide insights for designing peptides tailored to function as anion receptors in diverse supramolecular chemistry applications.

Structural characterization of degradation products of phenol red used as zero permeability marker in in-situ rat intestinal permeability studies by LCMS-IT-TOF

In this study, the quantitative determination of phenol red with using HPLC, the permeability marker widely used in gastrointestinal studies, and its stability in various apolar phase solvents were investigated. In addition, the mechanisms of degradation products obtained were tried to be elucidated by using the LCMS-IT-TOF device. The proposed HPLC method utilizes a Perkin Elmer C18, 5 μm, 250 mm × 4.6 mm i.d. column, a mobile phase consisting of phosphate buffer and methanol in the proportion of 50:50 (v/v) with apparent pH adjusted to 3.2 and detected at 430 nm using a photodiode array detector. The method exhibits linearity within the concentration range of 5–200 µg/mL, with a calculated R2 of 0.9981. In situ conditions, the recovery is in the range of 89.8–103.6 %. Furthermore, high-resolution mass studies were identified three degradation products that occur when phenol red was dissolved either ethanol or methanol medium. The method has a low cost of consumables and is very easy to apply to the procedure and analyze degradation products while easily applied to phenol red analysis in various mediums. High-resolution mass screening analysis confirmed the proposed structure of the degradation product. The validation and robustness studies were fulfilled to display the performance of the method in various analytical environments. The greenness and blueness evaluations of the developed method were also made in detail. The AGREE score of the method was calculated as 0.64, AGREEprep 0.68, MoGAPI 0.78, and BAGI scale score as 65.0. In short, the method is perfectly green, applicable, and practical. Finally, phenol red concentrations analyzed in samples obtained in in-situ animal studies were conducted to demonstrate the applicability of the developed method.

Cation-lone pair interaction in Alkali/alkaline earth metal ion-heavier borazine analogue complexes.

The present study is the first report on the formation of alkali/alkaline earth metal ion-heavier borazine analogue complexes via cation-lone pair interaction. Density functional calculations are performed in scrutinizing the complex formation between alkali (Li+, Na+, K+)/alkaline earth (Be2+, Mg2+, Ca2+) metal ions and heavier borazine analogues (HBA) viz. B3P3H6, Al3N3H6, Al3P3H6, Al3As3H6, and Ga3P3-H6. The complexes are found to be stable in gas phase with stabilization energies within the range 26.40 to 324.74 kcalmol-1. The stability can be attributed to the polarizing power of the involved metal ions. Presence of solvent phase exerted notable impact on the stability of the complexes; stability is reduced significantly with the increase in solvent polarity. The process of complexation is exothermic and spontaneous. QTAIM analysis indicated the presence of both ionic and covalent interaction between HBAs and metal ions. HOMO energy, Wiberg bond index, NCI-isosurface and RDG plot analysis revealed the major role of cation-lone pair interaction in the complexation process.

Spectroscopic, quantum computational, molecular dynamic simulations, and molecular docking investigation of the biologically important compound-2,6-diaminopyridine

To establish the role in future drug development, 2,6-diamino pyridine (2,6-DAP) was investigated experimentally using computational tools. NMR (1H,13C), FTIR, and UV–Vis spectra were analyzed for the titled compound. The molecular structure was optimized via DFT with the “B3LYP method with 6-311++G(d,p)” The optimized parameters of the structure were assessed with the observed bond characteristics. The vibrational frequencies were studied, PED was carried out, and the calculated vibrational frequency obtained was compared with the experimentally obtained FTIR. NMR (1H,13C) was calculated and compared with the experimentally obtained spectra. UV–vis spectra are calculated in the gaseous phase and different mediums of solvents (methanol, DMSO) by employing the PCM solvent model and TD-DFT method, and the estimated value was compared with experimentally measured data. NBO analysis was done to study the donor-acceptor interaction. The extent of electron charge transfer inside the molecular structure was examined using HOMO–LUMO energy values. The study of excitation analysis led to the creation of E.D.D and H.D.D maps in methanol and DMSO. The AIM and ELF analysis was employed to compute the iso-surface projections, ellipticity, and binding energies. The MEP and Fukui functions evaluate the molecule’s reactive zones. Hirshfeld research was done to analyze interactions among the molecules in the structure of the crystal, and 3D Hirshfeld tops and 2D fingerprint layouts were developed. The molecular docking procedure was used, followed by a 100 ns MD simulation and computation of binding free energy found to delineate the binding affinity of the molecule toward human carbonic anhydrase II (HCA II). Molecular docking studies with several receptor proteins were also conducted to determine the most effective protein-ligand interactions. Biological assessments like drug-likeness also act upon the compound to verify the molecule’s drug-like nature.

Green liquid supra molecular solvent (SUPRA) phase for fast and selective liquid-liquid micro-extraction of Co2+ ions from aqueous samples

The limitation of Liquid-liquid micro-extraction (LLME) procedures can be the need for the use of a dispersive solvent which should be soluble in both of aqueous and organic phases. In this research, a new method named SUPRA-based LLME, is introduced which uses supra molecular solvent (SUPRA), as an environmentally friendly solvent, for quantitative and selective extraction of Co2+ ions from its aqueous solution via liquid-liquid micro-extraction process. The aqueous immiscible SUPRA phase, composed of vesicles of decanoic acid was synthesized via ex-situ procedure and used as a single liquid phase. In order to make the SUPRA phase selective, N, Nʹ-disalicylidene-3, 4-diaminotoluene (H2dst) was synthesized and completely dissolved in the SUPRA phase. Then the lipophilic and selective prepared liquid sorbent, as liquid SUPRA phase, was used for the facile and selective LLME of Cobalt (II) ions from aqueous samples. Experimental studies showed that there was not any need of dispersing solvent and so liquid SUPRA phase could easily dispersed in the aqueous phase and then separated by centrifugation as the supernatant phase. Then the effects of some important variables on the extraction efficiency were also investigated and optimized. The results showed that under optimal conditions, efficient extraction of Cobalt (II) ions was achieved, about 99 % ± 2.7 (n = 10), in a short time of extraction (10 min), and the linear range of calibration curve was from 500 to 2500 μg L−1 of Cobalt(II) with correlation coefficient of 0.999. Also detection limit and pre-concentration factor were 150 μg L−1 and 35.2, respectively. Although the experimental conditions were optimized for extraction of only Co2+ ions, the selectivity study showed a high tendency of selective liquid SUPRA phase toward extraction of both of Co2+ and Ni2+ ions. The matrix effects on the SUPRA-based LLME of Co2+ ions from matrix samples, factory wastewater and sea-water, were studied and least matrix effects were observed.

A computational study on the detection properties of pristine, Al-, and Ga- doped Zn12O12 nanoclusters toward Deferiprone in gas and solvent phases

Electrochemical sensors have great potential in point-of-care diagnostic devices, benefiting from advancements in nanomaterials that enhance sensitivity and selectivity and reduce costs. This study theoretically investigates Deferiprone (DEF) sensing using pristine and aluminum – and gallium-doped Zn12O12 nanoclusters (AlZn11O12 and GaZn11O12) through a density functional theory (DFT) approach at the B3LYP-D level with a 6-311G (d, p) basis set. The results indicate DEF adsorption energies of −29.53 kcal mol−1 for Zn12O12, −42.19 kcal mol−1 for AlZn11O12, and −27.12 kcal mol−1 for GaZn11O12 in their most stable orientations. The adsorption of DEF significantly alters the energy gap (Eg) in the doped nanoclusters, highlighting the superior sensitivity of AlZn11O12 and GaZn11O12 for DEF detection. Transition theory calculations reveal a practical recovery time of 72.64 s for GaZn11O12, indicating favourable adsorption characteristics. Solvent effect studies show that the DEF/GaZn11O12 complex is stable in water, with a higher dipole moment reflecting increased water polarisation. UV-Vis analysis demonstrates that DEF adsorption on GaZn11O12 shifts the spectrum to higher wavelengths, indicating enhanced adsorption. Thus, GaZn11O12 is proposed as a promising candidate for DEF detection in both gas and solvent phases.

Single-Pass Demonstration of Integrated Capture and Catalytic Conversion of CO2 from Simulated Flue Gas to Methanol in a Water-Lean Carbon Capture Solvent.

Here, we demonstrate an integrated semibatch simultaneous CO2 capture and conversion to methanol process using a water-lean solvent, N-(2-ethoxyethyl)-3-morpholinopropan-1-amine (2-EEMPA), that serves as both the capture solvent and subsequent condensed-phase medium for the catalytic hydrogenation of CO2. CO2 is captured from simulated coal-derived flue gas at a target >90 mol % capture efficiency, with a continuous slipstream of CO2-rich solvent delivered to a fixed bed catalytic reactor for catalytic hydrogenation. A single-pass conversion rate >60 C-mol % and selectivity >80 C-mol % are observed for methanol at relatively low temperatures (<200 °C) in the condensed phase of the carbon capture solvent. Hydrogenation products also include higher alcohols (e.g., ethanol and propanol) and hydrocarbons (e.g., methane and ethane), suggesting that multiple products could be made offering adaptability with varied CO2-derived products. Catalyst activity and selectivity are directly impacted by the water content in the capture solvent. Anhydrous operation provides high catalyst activity and productivity, suggesting that water management will be a critical parameter in real-world operation. Ultimately, we conclude that the integrated capture and catalytic hydrogenation of CO2 are chemically viable and potentially more energetically efficient and cost-effective than conventional separate capture and conversion approaches.

Interfacial adsorption of ionic liquids (ILs) on graphitic carbon nitride (g-C3N4) nanosheets: A DFT study

The adsorption of nine common ionic liquids (ILs) on two well-known structures of graphitic carbon nitride (g-C3N4) nanosheets, including Triazine-g-C3N4 and Heptazine-g-C3N4 has been investigated using density functional theory (DFT) method in gas phase and water solvent. The interactions between the ILs and the nanosheets are characterized by several techniques, such as quantum theory of atoms in molecules (QTAIM) analysis, noncovalent interaction (NCI) plots, and energy decomposition analysis (EDA) method. Interestingly, the obtained results showed that electrostatic interactions have the highest contributions to the interaction energies between the ILs and the surfaces, followed by dispersion interactions and orbital interactions (ΔEelec > ΔEdisp > ΔEorb) The most important Van der Waals (vdW) interactions between the ILs and the surfaces include π–π, CH…N, CH…π (CN), and CN…X (X = F, N, O) interactions. On the other hand, the adsorption of ILs is accompanied by charge transfer from the surfaces to the ILs. The calculated adsorption energy (Eads) showed that the [Bmim][PF6] IL has the highest adsorption affinity on the Triazine-g-C3N4 (−28.28 kcal/mol) and Heptazine-g-C3N4 (−26.68 kcal/mol) surfaces. Thermochemistry calculations showed that the Eads, ΔHads, and ΔGads values of IL@surface complexes decrease on moving from gas phase to water media. However, our results showed that the adsorption of ILs on the surfaces is still exothermic and proceeds spontaneously. Upon adsorption of ILs, a decrease in the HOMO–LUMO energy gap (Eg) is observed and is accompanied by an increase in the reactivity and electrophilic character of the surfaces. TD-DFT calculations showed that the weak adsorption of ILs leads to small red or blue shifts in the absorption bands of the Triazine-g-C3N4 and Heptazine-g-C3N4 surfaces. However, no significant changes are observed in the shape of the absorption spectra of the surfaces. Furthermore, the transition density matrix (TDM) heat maps of the IL@surface complexes showed that the electrons and holes are generally concentrated on the Triazine-g-C3N4 and Heptazine-g-C3N4 surfaces in the IL@surface complexes, signifying that the electronic transitions occur mainly on the surfaces.

Hydrogel granular systems for controlled release based on (co)polymers of 2-hydroxyethyl methacrylate with polyvinylpyrrolidone (a review)

The development of polymer carriers for systems of prolonged and controlled release of substances, particularly drugs, into the action environment is a relevant task in polymer chemistry and technology. This aims to solve the problem of reducing the effective dose of a medical drug administered into the body of a person or animal. The latest achievements in the field of creating such carriers in the form of spherical particles based on 2-hydroxyethyl methacrylate and polyvinylpyrrolidone (co)polymers are analyzed and summarized. The working principles and advantages of such systems are described. The research of the synthesis regularities, structure, properties and perspectives of application of granular hydrogels based on 2-hydroxyethyl methacrylate and its copolymers with polyvinylpyrrolidone was analyzed. The mixture of decanol and cyclohexanol as a solvent for the monomer phase is substantiated. Based on the analysis of kinetic studies, the optimal technological parameters for the suspension polymerization of 2-hydroxyethyl methacrylate with polyvinylpyrrolidone were selected, and the possibility of regulating the dispersion characteristics of copolymers via changes in the technological synthesis modes was confirmed. The results of studies on the sorption-desorption properties of copolymers concerning model substances and drugs are described. The possibility of directed regulation of sorption capacity and drug release rate through changes in copolymer composition was confirmed. Methods for increasing the sorption capacity of hydrogels for drugs are proposed.

Two Barriers Against the Cracking of Phase Change Materials Based on Gel Skeleton

AbstractA novel room‐temperature flexible, self‐healing PCM (denoted as PEG/PHMAC) based on gel skeleton was prepared in one‐pot free‐radical polymerization by using acrylic acid (AC) and hydroxyethyl methacrylate (HM) as monomers and polyethylene glycol (PEG) as phase change component and solvent. The as‐prepared samples exhibit excellent flexibility with a bending angle of up to 120° without fracture at room temperature, playing the role of the first barrier to effectively alleviate material fracture and failure caused by stress accumulation; in addition, because of the abundant hydrogen bonds in the material, it demonstrates outstanding self‐healing ability that deep rift can be quickly repaired within 30 min after the phase change, acting as the second barrier to self‐heal the cracks of PCM generated during long‐term heat storage/release cycles. Apart from that, these materials also show extraordinary antileakage and shape‐stable property without observation of any leakage or deformation at temperature much higher than the phase change temperature. It is also proved that this gel is suitable to act as adsorption skeleton of other PEG with different molecular weight and melting point feasible for different application scenarios. With so many merits, it is expected to provide some innovative ideas for the progress of PEG‐based PCM.

A QSPR Model for Henry's Law Constants of Organic Compounds in Water and Ethanol for Distilled Spirits.

Henry's law describes the vapor-liquid equilibrium for dilute gases dissolved in a liquid solvent phase. Descriptions of vapor-liquid equilibrium allow the design of improved separations in the food and beverage industry. The consumer experience of taste and odor are greatly affected by the liquid and vapor phase behavior of organic compounds. This study presents a machine learning (ML) based model that allows quick, accurate predictions of Henry's law constants (kH) for many common organic compounds. Users input only a Simplified Molecular-Input Line-Entry System (SMILES) string or a common English name, and the model returns Henry's law estimates for compounds in water and ethanol. Training was performed on 5,690 compounds. Training data were gathered from an existing database and were supplemented with quantum mechanical (QM) calculations. An extra trees regression model was generated that predicts kH with a mean absolute error of 1.3 in log space and an R2 of 0.98. The model is applied to common flavor and odor compounds in bourbon whiskey as a test case for food and beverage applications.

Thermodynamic study of pyridoxine in different solvents and temperatures: DFT study

The equivalent conductivities (Λ) of B6 vitamin (pyridoxine) in HշՕ and MeOH were measured at different temperatures between 293 to 313 K, as well as in mixtures of H₂O and MeOH at percentages of 10, 20, 30, 40, and, 50% MeOH at 310 K. All the practical results were mathematically processed using the Lee Wheaton equation, which is applied to the derived conductivity of electrolytes with a similar composition (1:1). This equation calculates various conductivity components, including the equivalent conductance at infinite dilution (Λₒ), the ionic conductivity, the distance between ions (R), and also the constant of ionic aggregation (Ka) at best-fit values of (ϬΛ). The values of these parameters differed from one solvent to another depending on the molecular interactions in the solution and the physical properties of the solvents, such as viscosity and dielectric constant. Finally, thermodynamic quantities for the ion association reaction (ΔG°, ΔH°, and ΔS°) were also studied. Density functional theory (DFT) calculations (B3LYP/6-31G (d,p)) were employed to analyze vitamin B6 in the gas phase and diverse solvents. Three different continuum methods, namely AM1, PM3, and HF, were utilized, followed by DFT. The final method was utilized to explore the effects on its characteristics. KEY WORDS: Electrical conductivity, Lee-Wheaton equation, Theoretical chemistry, DFT. Bull. Chem. Soc. Ethiop. 2025, 39(1), 165-176. DOI: https://dx.doi.org/10.4314/bcse.v39i1.14

Convenient Aqueous‐Phase Synthesis of Covalent Organic Frameworks for Anhydrous Proton Conduction

Covalent organic frameworks (COFs) as a kind of emerging materials has been widely concerned. Developing and recovering new COF materials is of great importance for anhydrous proton conduction, most of the synthesis methods are not organic solvent phase or convenient enough, which would inevitably lead to solvent waste and increase environmental burden. Herein, a method of COF synthesis in aqueous phase is developed, which is used for nonpolluting and sustainable fabrication. Benefits from the suitable channels and stability of HCOF‐1, the composite material H3PO4@HCOF‐1 exhibit high proton conductivity (1.29 × 10−4 S cm−1) at 413 K and the crystallinity of HCOF‐1 is maintained well after measurements. This work broadens the scope of COF synthesis and promotes the development of anhydrous proton conduction.

A first-principles adsorption study of functionalized carbon, boron nitride, silicon carbon nanotubes with ifosfamide as vehicles for drug delivery: Thermal analysis

We investigated the adsorption of ifosfamide (IFS) on the outer surface of zigzag (10, 0) carbon nanotubes (CNT), boron nitride nanotubes (BNNT), and silicon carbon nanotubes (SiCNT), using density functional theory (DFT) calculations at the PBE-D3 level in a water solvent phase. Based on zero-point corrected binding energies (Ebin), IFS exhibits chemisorption through its O-head and Cl-head on CNT (−1.05 eV) compared to BNNT (−0.93 eV), characterized by covalent interaction. In contrast, IFS undergoes physisorption via its O-head on SiCNT with binding energy of −0.68 eV as the most stable model this interaction is driven by electrostatic forces. The formation of complexes between the drug and nanotubes is influenced by charge transfer dynamics. Our thermodynamic analysis demonstrates the Gibbs free energy (ΔG) and enthalpy energy (ΔH) for all models are exothermic and spontaneous. The observed decrease in binding energy for BNNT and CNT correlates with changes in their energy gap, dipole moment, and charge transfer upon IFS adsorption. Notably, SiCNT exhibits a different response with a significant energy gap change leading to an increase in dipole moment and charge transfer. These findings suggest that these nanotubes demonstrate promising sensitivity to the presence of IFS and could be explored as potential drug delivery systems for this drug.