Solvation Energy Research Articles

Bioinformatics and computational studies of chabamide F and chabamide G for breast cancer and their probable mechanisms of action

Globally, the prevalence of breast cancer (BC) is increasing at an alarming level, despite early detection and technological improvements. Alkaloids are diverse chemical groups, and many within this class have been reported as potential anticancer compounds. Chabamide F (F) and chabamide G (G) are two dimeric amide alkaloids found in a traditional medicinal plant, Piper chaba, and possess significant cytotoxic effects. However, their scientific rationalization in BC remains unknown. Here, we aimed to investigate their potential and molecular mechanisms for BC through in silico approaches. From network pharmacology, we identified 64 BC-related genes as targets. GO and KEGG studies showed that they were involved in various biological processes and mostly expressed in BC-related pathways such as RAS, PI3K-AKT, estrogen, MAPK, and FoxO pathways. However, PPI analysis revealed SRC and AKT1 as hub genes, which play key roles in BC tumorigenesis and metastasis. Molecular docking revealed the strong binding affinity of F (− 10.7 kcal/mol) and G (− 9.4 and − 11.7 kcal/mol) for SRC and AKT1, respectively, as well as the acquisition of vital residues to inhibit them. Their long-term stability was evaluated using 200 ns molecular dynamics simulation. The RMSD, RMSF, Rg, and SASA analyses showed that the G-SRC and G-AKT1 complexes were excellently stable compared to the control, dasatinib, and capivasertib, respectively. Additionally, the PCA and DCCM analyses revealed a significant reduction in the residual correlation and motions. By contrast, the stability of the F-SRC complex was greater than that of the control, whereas it was moderately stable in complex with AKT1. The MMPBSA analysis demonstrated higher binding energies for both compounds than the controls. In particular, the binding energy of G for SRC and AKT1 was − 120.671 ± 16.997 and − 130.437 ± 19.111 kJ/mol, respectively, which was approximately twice as high as the control molecules. Van der Waal and polar solvation energies significantly contributed to this energy. Furthermore, both of them exhibited significant interactions with the binding site residues of both proteins. In summary, this study indicates that these two molecules could be a potential ATP-competitive inhibitor of SRC and an allosteric inhibitor of AKT1.

Computer-aided design, synthesis, and biological evaluation of 4-chloro-N-(2-oxo-3-(2-pyridin-4-yl)hydrazineylidene)indolin-5yl)benzamide and 1-(4-bromobenzyl)-5-indoline-2,3-dione against SARS-CoV-2 spike/ACE2

The emergence of the severe acute respiratory syndrome 2 (SARS-CoV-2) as a global threat has driven the urgent need for the identification of bioactive molecules capable of controlling or completely eradicating this virus. Our group has been investigating isatin hybrids that block the binding of the human angiotensin-converting enzyme 2 (ACE2) and the viral spike protein. This work describes the synthesis and biological evaluation of two derivatives of isatin (indol-2,3-dione) based on a computational approach. Isatin, a secondary metabolite of tryptophan, has been used as the core structure and is a versatile and favorable precursor and as a privileged scaffold against this enzyme complex. The new compound scaffolds AVS-01 and AVS-02 were designed by modifications at the C-3 and N-1 positions, respectively, according to the various reagents available in our lab. Molecular docking of the designed compounds was used to explore their interactions with the target protein complex. The two designed compound scaffolds shown in this article showed quite distinct docking glide scores (GScore = −3.657 and −4.534 for AVS-01 and AVS-02, respectively). Several analogs were synthesized and tested in the quest to find a plausible scaffold for further synthesis. While compound AVS-02 showed inhibition of spike/ACE2 binding with an IC50 value of 8.8 µM, the reference compound hopeaphenol inhibited the interaction with an IC50 of 0.3 µM. Compound AVS-01 rather showed no inhibition of the SARS-CoV-2 spike/host ACE2 interaction with an IC50 > 32 µM. An estimation of their binding free energy (ΔGbind), and free energy of solvation (ΔGsolv) MM-GBSA calculations was carried out to re-evaluate the affinity to the target protein to gain further insights into the observed activity and non-activity. MM-GBSA calculation showed that ΔGbind = −35.91 kcal/mol and-25.32 kcal/mol for AVS-01 and AVS-02, respectively, and ΔGsolv = 25.56 kcal/mol and 16.92 kcal/mol for AVS-01 and AVS-02, respectively. This leads to the conclusion that the N-1 position of the indole-2,3-dione moiety favors the blockage of SARS-CoV-2 spike/ACE2 interactions compared to the C-3 position. Analysis of GScores, per-residue interaction energies, and free energies of binding and solvation showed that van der Waals interactions should favor the binding towards the spike/ACE2 complex.

PW-SMD: A Plane-Wave Implicit Solvation Model Based on Electron Density for Surface Chemistry and Crystalline Systems in Aqueous Solution.

Electron density-based implicit solvation models are a class of techniques for quantifying solvation effects and calculating free energies of solvation without an explicit representation of solvent molecules. Integral to the accuracy of solvation modeling is the proper definition of the solvation shell separating the solute molecule from the solvent environment, allowing for a physical partitioning of the free energies of solvation. Unlike state-of-the-art implicit solvation models for molecular quantum chemistry calculations, e.g., the solvation model based on solute electron density (SMD), solvation models for systems under periodic boundary conditions with plane-wave (PW) basis sets have been limited in their accuracy. Furthermore, a unified implicit solvation model with both homogeneous solution-phase and heterogeneous interfacial structures treated on equal footing is needed. In order to address this challenge, we developed a high-accuracy solvation model for periodic PW calculations that is applicable to molecular, ionic, interfacial, and bulk-phase chemistry. Our model, PW-SMD, is an extension of the SMD molecular solvation model to periodic systems in water. The free energy of solvation is partitioned into the electrostatic and cavity-dispersion-solvent structure (CDS) contributions. The electrostatic contributions of the solvation shell surrounding solute structures are parametrized based on their geometric and physical properties. In addition, the nonelectrostatic contribution to the solvation energy is accounted for by extending the CDS formalism of SMD to incorporate periodic boundary conditions. We validate the accuracy and robustness of our solvation model by comparing predicted solvation free energies against experimental data for molecular and ionic systems, carved-cluster composite energetic models of solvated reaction energies and barriers on surface systems, and deep-learning-accelerated ab initio molecular dynamics (AIMD). Our developed periodic implicit solvation model shows significantly improved accuracy compared to previous work (namely, solvation models in aqueous solution) and can be applied to simulate solvent effects in a wide range of surface and crystalline materials.

Theoretical Investigations on Free Energy of Binding Cilostazol with Different Cyclodextrins as Complex for Selective PDE3 Inhibition.

Cilostazol is a phosphodiesterase III inhibitor characterized by poor solubility. This limitation can be overcome by using a drug carrier capable of delivering the drug to the target site. Cyclodextrins are essential as drug carriers because of their outstanding complexation abilities and their capacity to improve drug bioavailability. This study comprises two stages: The first involves verifying different cyclodextrins and their complexation abilities towards cilostazol. This was accomplished using molecular docking simulations (MDS) and density functional theory (DFT). Both techniques indicate that the largest Sulfobutyl Ether-β-Cyclodextrin forms the most stable complex with cilostazol. Additionally, other important parameters of the complex are described, including binding sites, dominant interactions, and thermodynamic parameters such as complexation enthalpy, Gibbs free energy, and Gibbs free energy of solvation. The second stage involves a binding study between cilostazol and Phosphodiesterse3 (PDE3). This study was conducted using molecular docking simulations, and the most important energetic parameters are detailed. This is the first such report, and we believe that the results of our predictions will pave the way for future drug development efforts using cyclodextrin-cilostazol complexes as potential therapeutics.

(Invited) Computational Framework and Insights Towards Electrolyte Design for Redox Flow Batteries

Achieving a fully renewable energy future requires the development of grid-scale energy storage technologies, and non-aqueous redox flow batteries (NRFBs) hold considerable potential.1 However, the redox-active materials (RAMs) currently in consideration as lead candidates for NRFBs exhibit shortcomings, including low solubility, impaired transport properties, and low reduction potentials. Utilizing theory and computation is invaluable in predicting the structure-property relationship of RAM as NRFB active materials. The numerous components within NRFB electrolytes, spanning solvents, active materials, and supporting salts, suggest that material discovery could experience a substantial acceleration through computational and machine-learning approaches.This presentation will provide a progress update on our efforts towards a computational framework involving quantum mechanical (QM), molecular dynamics (MD), and machine learning methods to predict fundamental chemical and physicochemical properties of redox-active materials for energy storage systems. We used an extremely stable, bio-inspired vanadium(4+) bis-hydroxyiminodiacetic acid (VBH) as the scaffold to explore the large parameter space of NRFB systems.2–4 First, we show our framework based on density functional theory (DFT) for calculating solubilities, incorporating both lattice and solvation energies, that can be calibrated and used with synthetic verifications. We found that lattice free energy, which has previously been neglected, has a significant role in tuning electrolyte solubility. Second, we describe our MD simulations on the concentration and composition dependence of transport properties, such as viscosity, using DFT-derived force field bonded parameters for the novel [VBH]2- anion to understand the interactions between the ions and the solvent. Third, we demonstrate that QM molecular design could finely adjust the reduction potential. These fundamental investigations would offer insights into electrolyte design and how molecular properties dictate the macroscopic properties that contribute to specific performance aspects of advanced battery electrolytes.1 Y. Huang, S. Gu, Y. Yan and S. F. Y. Li, Current Opinion in Chemical Engineering, 2015, 8, 105–113.2 H. Huang, R. Howland, E. Agar, M. Nourani, J. A. Golen and P. J. Cappillino, J. Mater. Chem. A, 2017, 5, 11586–11591.3 S. K. Pahari, T. C. Gokoglan, B. R. B. Visayas, J. Woehl, J. A. Golen, R. Howland, M. L. Mayes, E. Agar and P. J. Cappillino, RSC Adv., 2021, 11, 5432–5443.4 B. R. B. Visayas, S. K. Pahari, T. C. Gokoglan, J. A. Golen, E. Agar, P. J. Cappillino and M. L. Mayes, Chem. Sci., 2021, 12, 15892–15907.

Rate-Dependent Formation Processes in Li-O2 Batteries: Phase-Field Modeling with the Marcus Kinetics

Lithium-oxygen batteries (Li-O2) present a compelling prospect for the next generation of batteries owing to their exceptionally high theoretical energy density.[1] Yet, the performance of Li-O2 batteries is significantly limited by the current-dependent morphology of insulating oxides.[2-3] Existing mathematical models using Butler-Volmer kinetics exhibit uncertainties and inaccuracies.[4-5] In this study, we propose the integration of Marcus kinetics with the existing phase-field model to resolve a few outstanding inconsistencies between theoretical predictions and experimental discoveries. Notably, utilizing the Marcus kinetics enables a quantitative assessment of the role of solvation energy in current-dependet particle growth as opposed to film growth. Experimental results further verify the new theoretical predictions. This research offers valuable insights for the future design of Li-O2 batteries.[1] Bruce, P. G., Freunberger, S. A., Hardwick, L. J., & Tarascon, J.-M. (2012). Nucleation and growth of lithium peroxide in the Li-O2 battery. Nature Materials, 11, 19–29.[2] Read, J. (2002). Characterization of the Lithium/Oxygen Organic Electrolyte Battery. Journal of The Electrochemical Society, 149, A1190-A1195.[3] Kraytsberg, A., & Ein-Eli, Y. (2011). Review on Li–air batteries—Opportunities, limitations and perspective. Journal of Power Sources, 196, 886-893.[4] Lau, S., & Archer, L. A. (2015). Nucleation and growth of lithium peroxide in the Li-O2 battery. Nano Letters, 15(9), 6108–6114.[5] Horstmann, B., Gallant, B., Mitchell, R., Bessler, W. G., Shao-Horn, Y., & Bazant, M. Z. (2013). Rate-dependent morphology of Li2O2 growth in Li-O2 batteries. Journal of Physical Chemistry Letters, 4(24), 4227–4232.

The correlation of alkyl chain modulation and the efficiency of Y-series non-fullerene acceptor: A DFT approach

Y6, a highly efficient non-fullerene acceptor, could present distinctly different power conversion efficiency in organic solar cells when its alkyl side chains are replaced by others. However, the underlying mechanism is still unclear. To dissect this point, ten kinds of Y-series acceptors with variant side chains are studied. The density functional theory is used to calculate their ground geometry, frontier molecular orbital, ultraviolet–visible absorption spectra, the free energy of solvation, intramolecular electron transfer, and electronic structures on the excited state in chloroform. Results reveal that the presence of the branched R1 could reduce the dihedral angle and balance the planarity of molecular skeletons. The free energy of solvation is less than −1.5 eV and R2 has a greater impact on it than R1. Acceptors with longer R2 have better light absorption between 400 nm and 600 nm. Molecular dynamics simulation is also applied to the blending films with these acceptors and PM6. Molecules that possess branched R1 and longer R2 have a better morphology and are found to be promising candidates for highly efficient acceptors.

Pushing redox potentials to highly positive values using inert fluorobenzenes and weakly coordinating anions

While the development of weakly coordinating anions (WCAs) received much attention, the progress on weakly coordinating and inert solvents almost stagnated. Here we study the effect of strategic F-substitution on the solvent properties of fluorobenzenes C6FxH6−x (xFB, x = 1–5). Asymmetric fluorination leads to dielectric constants as high as 22.1 for 3FB that exceeds acetone (20.7). Combined with the WCAs [Al(ORF)4]− or [(FRO)3Al-F-Al(ORF)3]− (RF = C(CF3)3), the xFB solvents push the potentials of Ag+ and NO+ ions to +1.50/+1.52 V vs. Fc+/Fc. The xFB/WCA-system has electrochemical xFB stability windows that exceed 5 V for all xFBs with positive upper limits between +1.82 V (1FB) and +2.67 V (5FB) vs. Fc+/Fc. High-level ab initio calculations with inclusion of solvation energies show that these high potentials result from weak interactions of the ions with solvent and counterion. To access the available positive xFB potential range with stable reagents, the innocent deelectronator salts [anthraceneF]+∙[WCA]− and [phenanthreneF]+∙[WCA]− with potentials of +1.47 and +1.89 V vs. Fc+/Fc are introduced.

Solvent and media effects on the photophysics of cranad-2 and cranad-58

Alzheimer’s disease (AD) represents the most widespread form of age-related cognitive degeneration, characterized by long-term degenerative damage, cognitive dysfunction, and profound deficits in logical thinking, knowledge acquisition, and interpersonal communication. A principal biomarker of AD involves the emergence and aggregation of β-amyloid (Aβ). Cranad derivatives are fluorescent probes capable of detecting, quantifying, and imaging Aβ aggregates. In this work, the effect of solvent and microheterogeneous environments on the photophysical behavior of CRANAD-2 and CRANAD-58 was investigated employing a large solvent set and several microorganized systems. Both the absorption and fluorescence spectra exhibit a substantial solvatochromic effect, resulting in significant Stokes shifts. Application of linear solvation energy relationships to correlate the fluorescence spectra maxima and the Stokes shift with microscopic solvent parameters suggests significant intramolecular charge transfer during the excitation, as corroborated by the increased dipole moment in the excited state. Generally, fluorescence quantum yields determined for CRANAD-2 exceed those of CRANAD-58 in most solvents, with low values in polar solvents and bigger values in non-polar solvents. Introduction of CRANAD-2 and CRANAD-58 into micellar and vesicular solutions notably augments the fluorescence emission intensity, accompanied by a blue shift in the fluorescence maxima. The fluorescence maxima values observed within microheterogeneous systems closely parallel those reported for interactions between CRANAD derivatives and soluble or aggregated Aβ amyloids which potentially constrains the efficacy of “in vivo” Aβ detection trials, because localization of CRANAD derivatives in non-polar microenvironments present in biological media could interfere with the detection of amyloid fibers.

In-situ synthesis of quaternary alkylammonium ligand capped organic-inorganic hybrid halide perovskite for high pure green luminescence in display application

This study delves into the intricate dynamics of ligand engineering for the synthesis of Methyl Ammonium Lead Bromide (MAPbBr3) nanocrystals (NCs), which exhibit immense potential in optoelectronic and photovoltaic applications. Our focus centres on the role of the quaternary ammonium molecule CTAB as a ligand in stabilizing MAPbBr3 NCs. This also addresses the challenges related to the stability and surface defects of NCs that hinder their commercial viability. Employing a modified ligand-assisted reprecipitation technique (LARP) with a dual solvent system, we optimized the CTAB concentration to 0.05 mmol, resulting in MAPbBr3 NCs with an impressive 88% quantum yield. XPS and FTIR analyses confirm the presence and binding of CTAB on the NC surface. The MAPbBr3-CTAB NCs exhibit higher exciton–phonon binding energy, enhancing their optical properties. Despite an unfavourable geometric fit, CTAB is effective in surface defect passivation due to its binding, solvation, and desorption energy during the dynamic binding process. 2D-DOSY NMR reveals approximately 66% CTAB bound to the NC surface. A comparative study involving MAPbBr3-OA, OLA, and MAPbBr3-CTAB deposited on LEDs demonstrates the superior performance of the latter, achieving a luminous efficiency of 42.18 lm W−1 at 1.2 ml deposition. These findings highlight the efficacy of CTAB in achieving high-purity green luminescence, aligning with BT.2020 display colour standards and paving the way for advanced optoelectronic applications. The successful synthesis and improved performance of MAPbBr3-CTAB NCs underscore their potential as a promising material for future optoelectronic and photovoltaic technologies.

A 5 V Ultrahigh Energy Density Lithium Metal Capacitor Enabled by the Fluorinated Electrolyte

Lithium metal capacitor (LMC), incorporating a redox-type lithium metal anode and a capacitive-type carbon cathode, delivers a combination of high energy and power characteristics, which is regarded as a promising electrochemical energy storage system. However, the unstable interface stability of lithium anode and the unclear capacitive mechanism of carbon cathode seriously restrict the advancement of LMC. Herein, an all-fluorinated electrolyte with high voltage stability has been designed for engineering 5 V LMC. It is noticed that a high-quality LiF-rich solid electrolyte interphase derived from all-fluorinated electrolyte effectively improves the interfacial stability of lithium metal anode, boosting the reversible Li plating/stripping behavior and suppressing dendrite growth. Moreover, analyzed by the thermodynamic perspective, the stable PF6−(FEC)2(FEMC)4 configuration with the lowest solvation energy mainly exists in the all-fluorinated electrolyte, which reveals that the suitable pore size distribution (1.3–4.6 nm) can ensure the strong adsorption/desorption process. Endowed by the all-fluorinated electrolyte, the established 5 V LMC paired with an optimized porous carbon sheet cathode manifests excellent electrochemical performances with an ultrahigh energy density of 537.6 Wh kgcathode−1 and a large power density of 17500 W kgcathode−1. This elaborate work affords in-depth insights based on fluorinated electrolyte strategy into the fabrication guidance of LMC.

Identification, screening and molecular mechanisms of natural stable angiotensin-converting enzyme (ACE) inhibitory peptides from foxtail millet protein hydrolysates: a combined in silico and in vitro study.

The stability of bioactive peptides under various food processing conditions is the basis for their use in industrial manufacturing. This study aimed to identify natural ACE inhibitors with excellent stability and investigate their physicochemical properties and putative molecular mechanisms. Five novel ACE inhibitory peptides (QDPLFPL, FPGVSPF, SPAQLLPF, LVPYRP, and WYWPQ) were isolated and identified using RP-HPLC and Nano LC-MS/MS with foxtail millet protein hydrolysates as the raw material. These peptides are non-toxic and exhibit strong ACE inhibitory activity in vitro (IC50 values between 0.13 mg mL-1 and 0.56 mg mL-1). In addition to QDPLFPL, FPGVSPF, SPAQLLPF, LVPYRP, and WYWPQ have excellent human intestinal absorption. Compared to FPGVSPF and SPAQLLPF, the stable helical structure of LVPYRP and WYWPQ allows them to maintain high stability under conditions that mimic gastrointestinal digestion and various food processing (temperatures, pH, sucrose, NaCl, citric acid, sodium benzoate, Cu2+, Zn2+, K+, Mg2+, Ca2+). The results of molecular docking and molecular dynamics simulation suggest that LVPYRP has greater stability and binding capacity to ACE than WYWPQ. LVPYRP might attach to the active pockets (S1, S2, and S1') of ACE via hydrogen bonds and hydrophobic interactions, then compete with Zn2+ in ACE to demonstrate its ACE inhibitory activity. The binding of LVPYRP to ACE enhances the rearrangement of ACE's active structural domains, with electrostatic and polar solvation energy contributing the most energy to the binding. Our findings suggested that LVPYRP derived from foxtail millet protein hydrolysates has the potential to be incorporated into functional foods to provide antihypertensive benefits.

A comparative study of two α-L-rhamnosidases with high sequence identity

The GH78 α-L-rhamnosidase from Aspergillus tubingensis (AT-Rha) was proved to be a new clade of Aspergillus α-L-rhamnosidases in the previous study. A putative α-L-rhamnosidase from A. kawachii IFO 4308 (AK-Rha) has 92 % identity in amino acid sequence with AT-Rha. In this study, AK-Rha was expressed in P. pastoris and characterized. Similar to AT-rRha, the recombinant AK-Rha (AK-rRha) showed a narrow substrate specificity to naringin. Interestingly, the enzyme activity of AK-rRha was 0.816 U/mg toward naringin, significantly lower than 125.142 U/mg of AT-rRha. Their large differences in catalytic efficiency was mainly due to their differences in kcat values between AK-rRha (0.67 s−1) and AT-rRha (4.89 × 104 s−1). The molecular dynamics simulation exhibited that the overall conformation of AK-Rha was rigid and that of AT-Rha was flexible; the Loop Y-L located above the catalytic domain formed different steric hindrances to naringin, and interacted with the flavonoid matrices at different strengths. The polar solvation energy analysis implied that the glycosidic bond was more easily hydrolysed in AT-Rha. The comparative study verified that the main feature of AK-Rha and AT-Rha represented Aspergillus α-L-rhamnosidase was the narrow substrate specificity toward naringin, and provided an insight of the relationships between their catalytic abilities and structures.

Preparation of dicationic ionic liquid modified silica stationary phase for mixed-mode liquid chromatography and its application for food additive detection

BackgroundFood safety has become an essential aspect of public concern and there are lots of detection means. Liquid chromatography plays a dominating role in food safety inspection because of its high separation efficiency and reproducibility. However, with the increasing complexity of real samples and monitoring requirements, conventional single-mode chromatography would require frequent column replacement and cannot separate different kinds of analytes on a single column simultaneously, which is costly and time-consuming. There is a great need for fabricating mixed-mode stationary phases and validating the feasibility of employing mixed-mode stationary phases for food safety inspection. ResultsThis work fabricated multifunctional stationary phases for liquid chromatography to determine diverse food additives under the mixed mode of RPLC/HILIC/IEC. Two dicationic ionic liquid silanes were synthesized and bonded onto the silica gel surface. The functionalized silica was characterized by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and elemental analysis. Both columns provide satisfactory separation performance towards 6 hydrophilic nucleosides, 4 hydrophobic polycyclic aromatic hydrocarbons, and 5 anions. Great repeatability of retention (RSD <0.1 %) and column efficiency (100330 plate/m) were obtained. Thermomechanical analysis and linear solvation energy relationship investigated the retention mechanism. Finally, the better in two prepared columns was employed to separate and determine the contents of NO2− and NO3− in vegetables(highest 4906 mg kg−1 NO3− in spinach), preservatives in bottled beverages (180.8 mg kg−1 sodium benzoate in soft drink), and melamine in milk with satisfactory performance and recovery rates ranging from 96.4 % to 105.6 %. SignificanceThis work developed a novel scheme for preparing mixed-mode stationary phases by dicationic ionic liquid which provides great separation selectivity. Most importantly, this work proved the superiority of employing mixed-mode stationary phases for food safety inspection, which might avoid high-cost and frequent changes of columns and chromatography systems in the near future.

Anti-Coulomb ion-ion interactions: A theoretical and computational study

The free energy of ion solvation can be decomposed into enthalpic and entropic contributions. This helps one to understand the connection between the dielectric properties and the underlying forces. We present a simple linear-response model of screened charge interactions that provides an alternative understanding of solvation barriers. Moreover, it explains the “anti-Coulomb” interactions (attraction between like-charged ions and repulsion between opposite-charged ions) observed in both simulations and experiments. We show that this is a universal behavior associated to the nonlocal response function of any dielectric or metallic systems. Published by the American Physical Society 2024

Investigation on itraconazole solubility in aqueous solutions based on models, solvent effect, thermodynamic analysis and quantum chemical calculations

The mole-fraction solubility of itraconazole in four aqueous blends of ethanol/isopropanol/DMSO/methanol within the temperature range of 283.15 to 323.15 K was experimentally obtained using the isothermal shake-flask method. Under the identical temperature and ethanol/isopropanol/DMSO/methanol composition, itraconazole solubility in DMSO+water is much higher than that in ethanol/isopropanol/methanol + water. At the same temperature, the solubility increases monotonically with organic solvent concentration. X-ray power diffraction analysis demonstrated that over the course of the investigations, there was no crystal transition or solvate formation. The modified van’t Hoff-Jouyban-Acree and Jouyban-Acree models adequately related the solubility to solvent composition and temperature, with relative average deviations (RADs) not exceeding 7.65 %. Furthermore, the extended Hildebrand solubility approach was utilized to quantitatively characterize the solubility behavior at 298.15 K for the mixtures of ethanol/isopropanol/DMSO/methanol plus water. In both instances, the RADs were maintained below 4.12 %. The solubility parameter and dipolarity-polarizability of solutions have a major impact on the solubility fluctuation, as indicated by the analysis of the linear solvation energy relationship. The preferential solvation of itraconazole at 298.15 K was examined using the efficient approach of inverse Kirkwood-Buff integrals. The preferred solvation parameters showed positive values in blends within rich and moderate ethanol/isopropanol/DMSO/methanol composition regions. This suggests that the organic solvents preferentially solvated itraconazole. When itraconazole dissolved in the blends, thermodynamic analysis of the entropy-enthalpy compensation and dissolution parameters revealed both an endothermic and an enthalpy-driven mechanism. Furthermore, the microscopic electrostatic characteristics of basicity and acidity were effectively demonstrated by means of the electrostatic potential of molecular surface. The −C=O and −N=groups of the itraconazole molecule, which link the five-membered ring, are the primary targets of the electrophilic attack. An independent gradient model based on Hirshfeld partition analysis was used to demonstrate the weak interactions between itraconazole and solvents.

Unlocking guanine’s potential: Unveiling electronic transitions and nanoelectronic applications through electric field modulation

Guanines, key players in DNA and RNA, exist as dynamic keto and enol forms, influencing reactivity and potential applications. This study explores the impact of external electric fields on these forms using computational methods in gas and solvent (water) phases. Analyzing the energy gap, dipole moment, enthalpy, and Gibbs free energy revealed distinct responses. The keto form showed a significant decrease in the energy gap in the presence of an electric field, particularly in water, indicating enhanced reactivity. Conversely, the enol form exhibited a stabilizing effect with increasing electric field strength. Thermodynamic properties highlighted solvent-dependent interactions and electric field-induced changes in electron density distribution. The study further investigated guanine’s potential for nanoelectronics by calculating I-V curves, revealing promising characteristics, especially for the keto form in the aqueous phase. Additionally, the analysis of solvation and cohesive energies provided insights into solute–solvent interactions and intrinsic molecular stability. Overall, this research contributes to understanding how guanine responds to electric fields, paving the way for novel guanine-based materials with potential applications in nanoelectronics.

Vibrational assignments of monohydrate dimer of violuric acid by using FT-IR, FT-Raman and UV spectra and DFT calculations in different media

Experimental FT-IR, FT-Raman and UV spectra have been combined with hybrid B3LYP/6–311++G** calculations and the scaled quantum mechanical force field (SQMFF) methodology to study structural and vibrational properties of monohydrated dimer (MD) of violuric acid in gas and aqueous media. Complete vibrational assignments and its scaled force constants are reported together with the corresponding to anhydrous and monohydrate monomer. From four anhydrous C1, C2, C3, C4 monomers, C4 is the most stable in both media. In solution, the initial structure of C2 change to the tautomeric species most stable C4. The MD reveals a higher solvation energy while natural bond orbital (NBO) and atoms in molecules (AIM) calculations support the higher stability of this species due to the six H bonds interactions and to its higher expansion of volume in solution. The MD is the most reactive species, as revealed by the lowest gap value and by high global electrophilicity and most negative global nucleophilicity indexes. Very good concordances are observed among the predicted IR, Raman, 13C NMR and UV spectra and the corresponding experimental ones. Comparisons of predicted 13C NMR and electronic spectra with the experimental one show that those three species of violuric acid could be present in aqueous solution. Similar f(νC=O) and f(νC-O) force constants for the three species are justified by the important delocalization of electrons evidenced in anhydrous and monohydrate species by NBO calculations.

Standard partial molar volumes of single aqueous ions composing ionic liquids. Measurement and evaluation of temperature dependent values. Parsing and LSER correlation with molecular descriptors based on DFT/COSMO approach

The densities of highly dilute aqueous solutions (m < 0.2 mol·kg−1) of 50 common ionic liquids (ILs) or related salts were accurately measured at seven equidistant temperatures in the range of (288.15 to 318.15) K and ambient pressure. The examined set of ILs/salts composed of 31 ions was judiciously selected to cover wide ranges of ion sizes and chemical structures and allow reliable evaluation of ionic contributions. The data were duly analyzed to infer related thermodynamic properties and information on the behavior of these systems on a molecular level. Appropriate means of mathematical statistics were used to estimate data uncertainties, assign weights to data correlations, and judge the significance of the results obtained. The standard partial molar volumes V¯∞ of the ILs/salts at infinite dilution were evaluated through fitting the concentration dependence of respective apparent molar volumes to Redlich-Meyer equation and their temperature dependence was correlated to quadratic polynomial. The data presented were compared whenever possible with those available in the literature; good agreement was often found, although some data from the literature were also considerably dispersed or in error. Standard partial molar volumes of ILs/salts obeying ionic additivity were split by least-squares optimization into temperature-dependent single-ion values based on the Conway-Millero extrathermodynamic assumption. The ionic additivity of BV parameter was also identified. Its magnitude for anions is typically greater than that for cations, supporting the fact that an anion dominates the volumetric behavior of aqueous ILs. As the BV,anion and the second temperature derivative ∂2V¯anion∞/∂T2 were found to correlate, the two solute’s water structure making/breaking ability indicators appear to speak consistently. Enhanced values of standard partial molar expansion were observed for both strongly kosmotropic and chaotropic anions and a plausible explanation of this phenomenon was suggested. To correlate and analyze the effect of ionic structure on V¯ion,298∞, Linear Solvation Energy Relationship (LSER) methodology with the recently proposed four quantum chemistry computed descriptors based on DFT/COSMO approach was employed providing excellent fit (SD = 2.48 cm3·mol−1, R2 = 0.9996).

Fast Li-ion battery chemistry enabled by small-sized solvent

Carbonate-based electrolytes, known for their high solvation energy and high ionic conductivity at room temperature, present significant challenges in ultra-low temperature and fast charging applications. In the February issue of Nature, Fan and colleagues demonstrated that utilizing solvents like fluoroacetonitrile with small molecular size and low solvation energy, facilitates the creation of rapid ion-conduction ligand channels and enables the formation of an inorganic-rich interphase for high-performance ionic batteries, effectively addressing the aforementioned challenges.