Solute Molecules Research Articles

What is behind a gas stream scrubbing liquid? Monoethanolamine/water mixtures as seen by dielectric relaxation spectroscopy.

High-quality dielectric data for monoethanolamine (MEA)/water mixtures covering the entire miscibility range are presented. For MEA concentrations c1 ≥ 1 M the obtained complex permittivity spectra, covering the frequency range from 0.05 to 89 GHz, are best described by a sum of four Debye relaxations. Modes at ∼3 GHz and ∼10 GHz are solute-specific. Whilst the first can be assigned to MEA aggregates, the second is a composite arising from "free" MEA dipoles with dynamically retarded water hydrating them. The relaxations at ∼18 GHz and ∼200 GHz essentially reflect the cooperative H-bond fluctuations of more-or-less unperturbed "bulk" water, albeit with minor solute contributions. Evaluation of the bulk-water amplitude reveals that in water-rich mixtures (c1 ≤ 3.5 M) Zt = 3.5 ± 0.2 H2O molecules hydrate a MEA molecule. Then Zt drops linearly, reaching zero for neat MEA. Supported by the literature, this concentration dependence suggests that only H2O molecules H-bonded to the NH2 and OH groups of MEA contribute to Zt. At concentrations beyond hydration shell overlap (c1 ≥ 3.5 M) these H-bonds are gradually eliminated, while new interactions with neighboring MEA molecules are formed. From the evaluation of the MEA-specific amplitudes we conclude that for c1 ≥ 2 M, including neat MEA, ∼35% of the solute molecules are in aggregates, where breaking the intermolecular NH⋯O hydrogen bond determines the dynamics.

Solute translocation probability, lifetime, and "rectification" in membrane channels with localized constriction.

We study the translocation probability and lifetime of a solute molecule in a cylindrical membrane channel that contains a localized constriction at an arbitrary location. Using a one-dimensional continuous diffusion description of solute dynamics in the channel, we explore two models. The first one describes a molecule's interaction with the constriction in terms of a narrow rectangular barrier in the potential of mean force. The second novel model proposed here represents this interaction by introducing an infinitely thin permeable partition. It is shown that when the parameters of the two models are chosen to warrant the same translocation probability, both models predict the same mean lifetime of the molecule in the channel. While the translocation probability is independent of the constriction location, the mean lifetime is a function of the location. The benefit of the thin partition model is that it allows one to lump together the height and length of the potential barrier into a single parameter, which is the partition's permeability. It is shown that in the case of an asymmetric location of the localized constriction and strong repulsion between the solutes, the solute flux through the channel is a function of the direction in which it goes, analogous to the phenomenon known in ion channel electrophysiology as rectification.

Solution-based Supramolecular Hierarchical Assembly of Frenkel Excitonic Nanotubes Driven by Gold Nanoparticle Formation and Temperature.

Translating nature's successful design principle of solution-based supramolecular self-assembling to broad applications─ranging from renewable energy and information technology to nanomedicine─requires a fundamental understanding of supramolecular hierarchical assembly. Though the forces behind self-assembly (e.g., hydrophobicity) are known, the specific mechanism by which monomers form the hierarchical assembly still remains an open question. A crucial step toward formulating a complete mechanism is understanding not only how the monomer's specific molecular structure but also how manifold environmental conditions impact the self-assembling process. Here, we elucidate the complex correlation between the environmental self-assembling conditions and the resulting structural properties by utilizing a well-characterized model system: well-defined supramolecular Frenkel excitonic nanotubes (NTs), self-assembled from cyanine dye molecules in aqueous solution, which further self-assemble into bundled nanotubes (b-NTs). The NTs and b-NTs inhabit distinct spectroscopic signatures, which allows the use of steady-state absorption spectroscopy to monitor the transition from NTs to b-NTs directly. Specifically, we investigate the impact of temperature (ranging from 23 °C, 55 °C, 70 °C, 85 °C, up to 100 °C) during in situ formation of gold nanoparticles to determine their role in the formation of b-NTs. The considered time regime for the self-assembling process ranges from 1 min to 8 days. With our work, we contribute to a basic understanding of how environmental conditions impact solution-based hierarchical supramolecular self-assembly in both the thermodynamic and the kinetic regime.

Nanostructure-Based Solution Sensor Fabricated with p-CuOx/n-TiO2 Nanojunctions To Identify Species and Concentrations of Alcohol Molecules.

Chemiresistive sensors fabricated based on metal-oxide-semiconductors, the most widely used high-sensitivity sensor materials, are required for detecting target solutions and gases and identifying them with a high degree of accuracy. In this study, we used p-n nanojunctions and nanowire shapes for identifying alcohol solutions. The solution sensors fabricated based on CuOx nanowires with p-CuOx/n-TiO2 nanojunctions detected ethanol, ethylene glycol, and diethylene glycol solutions via DC voltage and electrochemical impedance measurements. The p-n nanojunctions affected the sensors' sensitivity in the diethylene glycol solution, and the nanowire surface areas affected the relaxation time in ethanol and ethylene glycol solutions. To identify alcohol solutions, principal component analysis was performed based on the relationship between the sensor information, such as the presence of p-n nanojunctions and nanowire surface areas, and the sensing performance. This analysis identified alcohol molecular species and predicted alcohol-solution concentrations in the 0.1-20 vol % range with a high degree of accuracy. The concept of using sensors with different surface conditions with respect to p-n nanojunctions and nanowire surface areas offers designs for metal-oxide-semiconductor sensors to identify various molecules in solution.

Liquid-Vapor Interface of Aqueous Ethylene Glycol Solutions: A Molecular Dynamics Study.

While the organic constituent in an aqueous binary solution enriches its liquid-vapor (l-v) interface, the extent of enrichment can depend nonlinearly on its mole fraction. A microscopic quantification and rationalization of this behavior are crucial to understand the dependence of properties such as surface tension and evaporation rate of the solution on its composition. Extensive all-atom molecular dynamics simulations of aqueous ethylene glycol (EG) solutions show that the composition of the solution at the l-v interface deviates the most from that in the bulk solution at an EG mole fraction of 0.3. The population of EG molecules with their central C-C dihedral in the gauche conformation was found to be higher at the l-v interface than that in the bulk solution to facilitate the orientation of its hydrophobic methyl groups toward the vapor phase. Free energy calculations reveal that in dilute EG solutions, an EG molecule is most stable at the l-v interface. The behavior of vapor pressure in aqueous EG solutions is ideal and follows Raoult's law, while in contrast, the aqueous solution of dimethyl sulfoxide does not. A rationale for the same is provided through the orientational distribution of interfacial water molecules in the respective solutions.

Antisolvent crystallization kinetics of different substances in solvent–antisolvent systems

Published experimental data of metastable zone width (MSZW) for the crystallization of four different solutes from their saturated solutions, determined as the maximum antisolvent content Δxmax, by addition of selected antisolvents as a function of feeding rate RA using theoretical equations based on power law (PL) and classical nucleation theory (CNT) are analyzed and trends of variations of the parameters of the equations and relationship between the parameters of the two approaches are discussed. With Δxmax taken in mole fraction of the antisolvent, from the analysis of the Δxmax(RA) data for the different investigated systems the following conclusions may be drawn:(1)The values of the parameters of the linear dependence of ln(Δxmax) on lnRA of the PL-based approach and those of the parameters of the linear dependence of (Δxmax)−2 on lnRA of the CNT-based approach are mutually related.(2)The preexponential factor A of the CNT, associated with the frequency of attachment of solute molecules with, and their detachment from, the growing three-dimensional nuclei, and their solute–solution interfacial energy γeff mainly depend on the product fa2, where f is the number of molecules or ions of solute per m3 in its saturated solution and a2 is the dimensionless solvent–antisolvent interaction parameter. The sequence of variation of γeff is opposite to that of the preexponential factor A.(3)The observed trend of variation of the nucleation constant K calculated from the analysis of antisolvent content Δxmax taken in mole fraction is similar to that of the A for different systems. However, A ≫ K and the ratio A/K ≈ 106.(4)The values of γeff obtained from the MSZW data of the investigated compounds are low and suggest the occurrence of their crystallization by heterogeneous nucleation.

Existence of original drug molecules in ultra high dilutions

Abstract:
 
 Background: Some workers postulated that homeopathic medicines have got some alterations of hydrogen bonded network in water molecules for their activity, but according to others the original drug molecule remains present as nanoparticles. Objective: To prove experimentally whether traces of medicine molecules are present in ultra high dilution and determine its apparent cause. Materials and Methods: To detect existence of Copper ion in 5 ultra high dilutions (6c, 30c, 200c, 1000c and 10000c) in Cuprum metallicum were subjected to Atomic Absorption Spectrophotometry. An experiment was also set up to determine how one can obtain trails of original molecules in highly diluted solutions beyond Avogadro’s limit where a solution of copper sulfate was successively diluted decimally in three different ways: NSW (Non-”Succussed” Water), SW(“Succussed” Water), SWE (“Succussed” Water with 50% ethanol) and was studied by UV-Vis Spectrophotometer. Result: Existence of a Copper ion was found asymptotically decreasing through all the five dilutions. In the second experiment it was observed that in case of NSW solution the Optical Density (OD) reaches to non-detectable (ND) range earlier, but for SW and SWE later. Conclusion: Some sorts of non-homogeneity established in “succussed” alcoholic dilutions due to fall of dielectric constant. With the increase of dilution more proportion of solute molecules in the form of nanoparticles covered by solvent layers become transferred to the next serial dilution. Drugs, tightly packed by ethanol (‘nanoparticles’) easily enter inside cell, bring symptoms to the “provers” and cure patients as well when applied in minute dose.

Soft-sphere continuum solvation models for nonaqueous solvents.

Solvation effects profoundly influence the characteristics and behavior of chemical systems in liquid solutions. The interaction between solute and solvent molecules intricately impacts solubility, reactivity, stability, and various chemical processes. Continuum solvation models gained prominence in quantum chemistry by implicitly capturing these interactions and enabling efficient investigations of diverse chemical systems in solution. In comparison, continuum solvation models in condensed matter simulation are very recent. Among these, the self-consistent continuum solvation (SCCS) and the soft-sphere continuum solvation models (SSCS) have been among the first to be successfully parameterized and extended to model periodic systems in aqueous solutions and electrolytes. As most continuum approaches, these models depend on a number of parameters that are linked to experimental or theoretical properties of the solvent, or that can be tuned based on reference data. Here, we present a systematic parameterization of the SSCS model for over 100 nonaqueous solvents. We validate the model's efficacy across diverse solvent environments by leveraging experimental solvation-free energies and partition coefficients from comprehensive databases. The average root means square error over all the solvents was calculated as 0.85 kcal/mol which is below the chemical accuracy (1 kcal/mol). Similarly to what has been reported by Hille et al. (J. Chem. Phys. 2019, 150, 041710.) for the SCCS model, a single-parameter model accurately reproduces experimental solvation energies, showcasing the transferability and predictive power of these continuum approaches. Our findings underscore the potential for a unified approach to predict solvation properties, paving the way for enhanced computational studies across various chemical environments.

Physicochemical studies of some bioactive molecules in aqueous solution of tetrabutylammonium methanesulphonate (TBAMS) to investigate assorted molecular interaction at different temperatures simultaneously optimized by computational approach

Aqueous tetrabutylammonium methanesulphonate (TBAMS) solvent was used to solubilize the simplest stable amino acid (AA) Glycine and protein maker amino acid (AA) L-Alanine, and their solution behaviour has been meticulously examined to explore how they interact under various temperature conditions, using parameters like density (ρ), viscosity (η), surface tension (σ), and electrolytic conductivity. 1H NMR was also performed to verify further the mode of interactions prevailing in the solution, which is further supported by the DFT study. This research primarily aims to understand the interactions between biologically significant TBAMS and important amino acids in aqueous solutions, with potential implications for the pharmaceutical field. These results are anticipated to contribute crucial foundational knowledge for grasping the influence of sugar alcohols on the stability of protein structures.

Role of explicit hydrogen bonding in solvation calculation on the photophysics of 2-(2′-Hydroxyphenyl)oxazolo[4,5-b]pyridine

The photophysics of 2-(2′-hydroxyphenyl)oxazolo[4,5-b]pyridine (HPOP) was theoretically examined by employing the integral equation formalism variant of polarizable continuum model (PCM) at the level of density functional theory with M06 functional. Polar protic methanol and water and aprotic acetonitrile and tetrahydrofuran, which have varied dielectric constants, were considered to study the role of polarity on the photophysics of HPOP and was compared with the results obtained in vacuum. Six different structural forms of HPOP were observed: cis and trans-closed enol, cis and trans-open enol, and cis and trans-keto. cis-closed enol is the most stable and trans-keto the least in the ground state. In the S1 state, cis-keto is the most stable and cis-open enol the most unstable. The relative stabilities of the different structures increase with the polarity of the solvent. The calculations were extended to vacuum and methanol environments by adding two methanol molecules, and similarly done with two water molecules in vacuum and water environments which are explicitly hydrogen bonded to HPOP at different hydrogen bonding centres of HPOP to study the role of solute–solvent hydrogen bond on its photophysics and the changes in results obtained under the PCM formalism. The hydrogen bond between the solute and solvent molecules further increases the relative stabilities of the different hydrogen bonded clusters. The calculations show that the intramolecular proton transfer (IPT) between cis-closed enol and cis-keto is a barrierless process with the transition state displaying a submerged barrier both in S0 and S1 states where the IPT occurs within a single OH stretching vibration. The IPT trajectory is shorter in the S1 state.

Investigation of intermolecular interactions of l-Valine and l-Phenylalanine with muscle relaxant drug mephenesin molecule prevalent in aqueous solution by various physico-chemical methods at T=298.15K–313.15K

A complete chemical analysis of significant intermolecular interactions of l-Valine (L-Val) and l-Phenylalanine (L-Phe) with Mephenesin (MEPN) molecules in aqueous solution has been studied by different physicochemical methodologies at various temperatures (T = 298.15 K–313.15 K at an interval of 5 K) and concentrations (0.001 mol kg−1, 0.003 mol kg−1, 0.005 mol kg−1) of aqueous MEPN solution. The limiting apparent molar volume (φV0) and experimental slope (SV*) values are found from the equation of Masson, viscosity A and B-coefficient determined using the equation of Jones-Doles, molar refraction (RM) and limiting molar refraction (RM0) derived by the Lorentz-Lorenz equation, express that in our experimental solution of amino acids (AAs) in aqueous MEPN, the solute-solvent interaction predominates over the solute-solute and solvent-solvent interactions for these ternary solutions. These are also justified by the measurement of various thermodynamic parameters, free energy of activation of viscous flow per mole of solvent(Δμ1°#) and solute (Δμ2°#), activation of viscous flow of enthalpies (ΔH°#) and entropies (ΔS°#). The characteristics of structure-breaking of solutes in the aqueous drug solution have been identified by Hepler's method and dB/dT value. The spectroscopic methods like UV–visible and proton-NMR studies help to explicate the strong AA-MEPN interactions in the solution phase and obtain a good correlation with theoretical studies. Theoretical investigations are checked to authenticate the experimental observations and according to both studies, L-Phe-MEPN interaction is greater than L-Val-MEPN interaction. The experimental and correlated research data are useful for the development of model combinations of AAs with drug molecules in pharmaceutical and medicinal chemistry.

Effect of Benzothiadiazole-Based π-Spacers on Fine-Tuning of Optoelectronic Properties of Oligothiophene-Core Donor Materials for Efficient Organic Solar Cells: A DFT Study.

In this work, five novel A-π-D-π-A type molecules D1-D5 were designed by adding unusual benzothiadiazole derivatives as π-spacer blocks to the efficient reference molecule DRCN5T for application as donor materials in organic solar cells (OSCs). Based on a density functional theory approach, a comprehensive theoretical study was performed with different functionals (B3LYP, B3LYP-GD3, B3LYP-GD3BJ, CAM-B3LYP, M06, M062X, and wB97XD) and with different solvent types (PCM and SMD) at the extended basis set 6-311+g(d,p) to evaluate the structural, optoelectronic, and intramolecular charge transfer properties of these molecules. The B3LYP-GD3BJ hybrid functional was used to optimize the studied molecules in CHCl3 solution with the SMD model solvent as it provided the best results compared to experimental data. Transition density matrix maps were simulated to examine the hole-electron localization and the electronic excitation processes in the excited state, and photovoltaic parameters including open-circuit photovoltage and fill factor were investigated to predict the efficiency of these materials. All the designed materials showed promising optoelectronic and photovoltaic characteristics, and for most of them, a red shift. Out of the proposed molecules, [1,2,5]thiadiazolo[3,4-d]pyridazine was selected as a promising π-spacer block to evaluate its interaction with PC61BM in a composite to understand the charge transfer between the donor and acceptor subparts. Overall, this study showed that adding π-spacer building blocks to the molecular structure is undoubtedly a potential strategy to further enhance the performance of donor materials for OSC applications.

Equilibrium solubilities, model analysis, solvent effect, molecular dynamic simulation, and thermodynamic properties of itopride hydrochloride in eleven organic pure solvents at different temperatures

Itopride hydrochloride is a novel prokinetic drug used to relieve gastrointestinal diseases. In this paper, the equilibrium solubility of itopride hydrochloride in selected eleven pure solvents (methanol, ethanol, 1-propanol, 2-methoxyethanol, 2-ethoxyethanol, 2-propoxyethanol, acetonitrile, N-methyl-2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide) was determined by the laser monitoring technique at temperatures ranging from 278.15 K to 323.15 K and pressures of 101.3 kPa. The experimental results showed that the equilibrium solubility of itopride hydrochloride in the selected pure solvents were all positively correlated with temperature and the order of equilibrium solubility at 298.15 K was: dimethyl sulfoxide (28.06)＞methanol (16.63)＞2-methoxyethanol (12.04)＞N-methyl-2-pyrrolidone (8.020)＞N,N-dimethylformamide (5.117)＞N,N-dimethylacetamide(3.576)＞2-ethoxyethanol (1.463)＞ethanol (0.9341)＞2-propoxyethanol (0.4850)＞1-propanol (0.2504)＞acetonitrile (0.1887). In addition, we used the λh model, modified Apelblat model, NRTL model and van't Hoff model to correlate the experimental data of the equilibrium solubility of itopride hydrochloride. Comparing the ARD and RMSD fitted by the four models, it was found that the NRTL model fitted the best, with the 100ARD value less than 5, and the mean values of 100ARD and 104RMSD were 2.15 and 1.61, respectively. Therefore, the NRTL model is more suitable for the correlation of equilibrium solubility data in this experiment. Furthermore, we analyzed the impact of different solvent properties on the equilibrium solubility of itopride hydrochloride, the molecular dynamics simulation was carried out and the interaction between solute and solvent molecules was analyzed by means of radial distribution functions (RDF). Finally, the apparent thermodynamic properties (ΔdisG°, ΔdisH°, ΔdisS°) of the phase equilibrium process of itopride hydrochloride in eleven organic pure solvents were analyzed by using the van't Hoff equation. The results of the analysis showed that it is entropically increasing and heat absorbing during the dissolution process of itopride hydrochloride.

Low Molecular Weight Shuttle Molecules Enhance Polychloramide Antimicrobial Activity.

Investigated were the influences of succinimide (SI), 5,5-dimethylhydantoin (DMH), and 3-(hydroxymethyl)-5,5-dimethylhydantoin (HDMH) on the biocidal activity of chlorinated, water-soluble polyamide prepared by the reaction of isopropylamine with poly(styrene-alt-maleic anhydride). The resulting polymer was a negatively charged, water-soluble polymer bearing a carboxylic acid and an isopropylamide moiety on nearly every repeat unit. Subsequent treatment with NaOCl chlorinated the polymers to up to 4.4% Cl while inflicting some polymer chain scission. SI, DMH, or HDMH increased the biocidal activity of polychloramides toward planktonic Escherichia coli and Staphylococcus aureus. Independent solution studies confirmed that oxidative chlorine spontaneously transferred from aqueous polychloramides to small molecules. We concluded that SI, DMH, and HDMH acted as shuttles that extracted oxidative Cl from the polymer chloramides and transported oxidative Cl more efficiently to microbial surfaces. Succinimide was the most effective shuttle. These results warn that some low molecular weight soluble molecules in antimicrobial testing solutions may exaggerate the effectiveness of the polymer or immobilized antimicrobial agents.

Water Fraction Dependence of the Aggregation Behavior of Hydrophobic Fluorescent Solutes in Water-Tetrahydrofuran.

This work investigates the water fraction dependence of the aggregation behavior of hydrophobic solutes in water-tetrahydrofuran (THF) and the elucidation of the role of THF using fluorescence microscopy, dynamic light scattering, neutron and X-ray scattering, and photoluminescence measurements. On the basis of the obtained results, the following model is proposed: hydrophobic molecules are molecularly dispersed in the low-water-content region (10-20 vol %), while they form mesoscopic particles upon increasing the water fraction to ∼30 vol %. This abrupt change is due to the composition fluctuation of the water-THF binary system to form hydrophobic areas in THF, followed by THF-rich droplets where hydrophobic solutes are incorporated and form loose aggregates. Further increasing the water content prompts the desolvation of THF, which decreases the particle size and generates tight aggregates of solute molecules. This model is consistent with the luminescence behavior of the solutes and will be helpful to control the aggregation state of hydrophobic solutes in various applications.

Solvent Media on Nonlinear Optical Properties of Triarylmethane Dye via Facile Z-Scan Method.

Solvent environment on third-order nonlinear optical (TNLO) features of triarylmethane dye namely, basic blue 7 in different solvents is reported herein using 650nm diode laser with continuous wave mode. The basic blue 7 dye is dissolved in different solvent media including ethanol, methanol, dimethyl formamide (DMF) and dimethyl sulfoxide (DMSO). The influence of solvent characteristics such as solvent polarizability and dipole moment on solute molecule is discussed. TNLO characteristics such as nonlinear optical index of refraction, nonlinear optical coefficient of absorption, real and imaginary components of the TNLO susceptibility are measured to be the order of 10‒7 cm2/W, 10‒3cm/W, 10‒6 esu and 10‒7 esu, respectively. The dye exhibits large TNLO susceptibility by dissolving in DMSO. The TNLO susceptibility of basic blue 7 dye is measured to be the order of 10‒6 esu. The overall results revealed that the basic blue 7 dye is suitable material for optoelectronics applications.

Resting time effect on the rheological behaviour of glass beads and cement suspension: The role of PCE size and ionic strength

AbstractStudies have shown that in an aqueous suspension of inert glass beads, the yield stress is increased as a function of resting time. This study investigates this unexpected phenomenon, focusing on solid surface potentials, PCE size in ionic solutions, and their possible relations to rheological behaviour with resting time. Results indicated that PCE in artificial pore solution will result in a higher yield stress with time. PCE with lower anionic charges and molecular weight can significantly increase the yield stress after 2 h of resting. The absolute value of the zeta potential grows to a certain degree after resting phase. Dynamic light scattering (DLS) results showed that the size of PCE molecules in ionic solutions increases over time, suggesting an enhanced depletion force or bridging force among glass bead particles, which could be the reasons for the increase in yield stress over time. Furthermore, the possible impacts of the depletion force or bridging force resulting from the PCE size change on the rheological properties of cement suspension are discussed.

Effects of polymeric surfactants with low HLB values on drug and excipient release from self-emulsifying drug delivery systems

In this study, we evaluated the effects of polymeric surfactants with low hydrophile–lipophile balance values (PSLH) lauryl PEG-8 dimethicone (LP8D) and Pluronic L121 (P121) on drug and excipient release from self-emulsifying drug delivery systems (SEDDS). Valsartan (logKOW 1.5) was used as a model drug, whereas oleic acid (logKOW 7.64) was loaded in SEDDS as a model excipient. Diffusion of valsartan from oil phase to aqueous phase was significantly reduced when adding 5 % LP8D or P121 into the oil phase consisting of isopropyl myristate:Capmul MCM 4:1 m/m. Drug diffusion reached plateau phases after 72 h compared to 3 h in case of the non-PSLH oil phase. Adding 10 % either LP8D or P121 further decreased drug diffusion to aqueous phase. P121 showed a more controlled drug diffusion profile than LP8D at the same loading level. PSLH were loaded in SEDDS preconcentrates at different concentrations in the ranges of 0–15 % LP8D and 0–10 % P121 m/m to yield emulsion with size ∼200 nm and polydispersity index <0.3 upon dilution. The burst release phases from PSLH loaded SEDDS were suppressed and better controlled with higher PSLH loading ratios. The presence of PSLH in the oil phase could increase intermolecular interactions such as hydrogen bonding and London dispersion forces between PSLH and drug or excipient molecules as shown by FTIR difference spectra. Furthermore, PSLH can accumulate at the oil-water interfacial barrier and increase the activation energy level for solute molecules diffusion, i.e. adding 10 % LP8D led to a 3-fold increase in activation energy for oleic acid. Therefore, incorporation of PSLH in SEDDS formulation could be a potential approach to reduce drug diffusion coefficients, enhance drug affinity to oil phase and control drug release rate.

Ultrafast vibrational control of organohalide perovskite optoelectronic devices using vibrationally promoted electronic resonance

Vibrational control (VC) of photochemistry through the optical stimulation of structural dynamics is a nascent concept only recently demonstrated for model molecules in solution. Extending VC to state-of-the-art materials may lead to new applications and improved performance for optoelectronic devices. Metal halide perovskites are promising targets for VC due to their mechanical softness and the rich array of vibrational motions of both their inorganic and organic sublattices. Here, we demonstrate the ultrafast VC of FAPbBr3 perovskite solar cells via intramolecular vibrations of the formamidinium cation using spectroscopic techniques based on vibrationally promoted electronic resonance. The observed short (~300 fs) time window of VC highlights the fast dynamics of coupling between the cation and inorganic sublattice. First-principles modelling reveals that this coupling is mediated by hydrogen bonds that modulate both lead halide lattice and electronic states. Cation dynamics modulating this coupling may suppress non-radiative recombination in perovskites, leading to photovoltaics with reduced voltage losses.

Morphology study of light– and pH–responsive amphiphiles with DSA for detection of nitrobenzene derivatives

Supramolecular molecular self–assemblies with 9, 10-distyrylanthracene (DSA) frameworks have good application prospects in fluorescent probes and optical materials owing to the unique AIE effect of the DSA unit. In this study, amphiphilic rod–coil molecules with rigid DSA parts and flexible oligoether chains were designed and synthesised, and their assembly capacities were investigated. The amphiphilic molecule with a lateral methyl unit in the coil branch formed worm–like supramolecular assemblies, while the molecule without lateral group self–assembled into an interwoven ribbon like structure in aqueous solution. This is due to noncovalent molecular interactions, such as the π–π stacking interaction of the rigid segments for the former or the hydrophilic–hydrophobic effect of molecules in the aqueous solution for the latter. Interestingly, under irradiation with 365 nm UV light, the original UV absorption of the molecule decreased and fluorescence quenching occurred, accompanied by a decrease in the size of the original aggregates, which became more apparent with as irradiation time increased, indicating the presence of photo-degradation. These molecular morphologies were also significantly influenced by the pH of the aqueous solution and produced nanoparticles of various sizes. Furthermore, we investigated the adsorption capacity of nitro compounds and found that molecular aggregates could be used for the detection of nitroaromatic compounds with strong electron-withdrawing groups.