Dichloromethane Solution Research Articles

Influence of 2,1,3-pyrazinochalcogenadiazoles structure on their dimerization via chalcogen bonding (chalcogen = S, Se, Te)

Chalcogen bonding (ChB) is an σ-hole-driven secondary bonding interaction (SBI). The crystalline 2,1,3-benzochalcogenadiazoles involved in organic optoelectronics is exemplified by [E···N]2 supramolecular synthon. For 5,6- R2 −2,1,3-pyrazinochalcogenadiazoles E-M and [E···N]2-bonded (E-M)2 (E = S, Se, Te; R / M = H / 1, Me / 2, CN / 3), gas-phase and dichloromethane solution calculations are performed. The molecular electrostatic potential suggests that changes in E, R influence σ- and π-holes of E-M / (E-M)2. Distant R acts via long-range electrostatic field effect. ChB strength increases in the order S < Se < Te, and (E-2)2 < (E-1)2 < (E-3)2. The main driving forces are electrostatic and dispersion interactions. Crystalline S-1 and Se-2 have head-to-head dimers. Se-3 shows head-to-tail chains via Se···NcyanoChB. A competition between different ChB, and, between ChB and other SBIs, should be considered in the design and synthesis of new E-M/(E-M)2 for fundamentals and applications.

Synthesis, structure, photo- and electroluminescent properties of methyl- and alkoxy-substituted 4-methyl-N-[2-(phenyliminomethyl)phenyl]benzenesulfamides and their zinc(II) complexes

A series of novel Zn(II) bischelate complexes based on azomethines of 2-(N-tosylamino)benzaldehyde and aromatic amines (aniline, 4-methylaniline, 4-methoxyaniline, 2-methoxylaniline, and 4-ethoxylanine) were designed and synthesized with the aim of studying their photo- and electro-luminescent properties. The structures of the synthesized azomethines and their complexes were studied by elemental analysis, infrared (IR) and proton nuclear magnetic resonance (1H NMR) spectroscopy. The structure of the Zn(II)-complexes was determined using X-ray diffraction analysis. In the solid state, azomethines exhibit bright luminescence in the yellow part of the spectrum with high emission efficiency and quantum yields of approximately 50%. Zinc complexes based on them exhibit noticeable luminescence in the solid state and in solutions of methylene chloride. Compared to azomethines, the luminescence maxima of Zn(II) complexes are hypsochromically shifted, and they exhibit pronounced blue-green luminescence. The OLED devices based on zinc(II) complexes emit strong bluish-green light with a peak maximum at 478-490 nm. The device with the best parameters has a maximum luminance of 2103 cd/m2, a current efficiency of 14.0 cd/A, and an overall efficiency of 4.8%, with a turn-on voltage of 3.6 V.

Immobilization of Levocetirizine on Mesoporous Silica for Antiallergenic Gel Formulation

Levocetirizine dihydrochloride is an effective antiallergenic drug applied mostly orally; however, developing a topical formulation for localized treatment could be beneficial. To achieve this, a modified formulation technique is necessary to enhance bioavailability efficiency and minimize possible side effects. Therefore, levocetirizine particles were prepared by immobilization on mesoporous silica material. Both the dihydrochloride form and its free base of levocetirizine were fixed on a silica-type Syloid support. Immobilization of the active ingredient levocetirizine in a free base form on a Syloid support by mixing in a dichloromethane solution provides better surface coverage (65.5%) than immobilization in the dihydrochloride form in water or methanol (24.5% for both). The successful binding of levocetirizine was confirmed by X-ray photoelectron spectroscopy and infrared measurements. The active ingredient in the form of hydrochloride is more likely to be in the pores, while the free base is bound to the surface in larger quantities. The time-dependent levocetirizine release showed that the liberation of the active ingredient from the Syloid is slower than the dissolution of the starting active ingredient itself, so it may be suitable for exerting a more reliable and prolonged local effect. A gel containing a Syloid-fixed levocetirizine free base was tested in vivo in a croton oil-induced ear edema mouse model. When compared to a reference gel, the half-dose formulation containing levocetirizine free base demonstrated a similar efficacy to Fenistil gel, indicating that the new formulation may offer superior effectiveness at lower doses.

Overcoming the Strong Sample Solvent Effect for Sustainability Measurement Challenges in Liquid Chromatography. Example for Bisphenol-A.

This paper describes an approach to achieve low parts per billion (ppb) concentration level detection using a reversed-phase ultrahigh-performance liquid chromatographic ultraviolet absorbance detection method with large-volume feed injection (FI) for analytes in dichloromethane (DCM). FI is a novel technology that allows sample injection at a defined speed into the LC mobile phase. We demonstrate this approach for a mixture of bisphenol A and its diglycidyl ether derivatives in DCM. DCM is a very strong injection solvent at reversed-phase LC conditions and is typically immiscible with a starting reversed-phase gradient mobile phase containing a high percentage of water. As a result, reduced separation performance and even peak splitting are seen with classic flow-through injection. The method setup comprised an octyl-bonded core-shell stationary phase (150 × 4.6 mm i.d., 2.7 μm particle size) with a water/acetonitrile mobile phase gradient and an exceptionally high injection volume of 45 μL of DCM solution using FI. Optimization of feed speed (1%) and isocratic hold duration (4 min) was crucial for final separation conditions. FI delivered more than a 20-fold improvement in the limit of detection (LOD) compared to standard flow-through injection while maintaining peak resolution. The LOD of the final method ranged between 1 and 10 ppb in the polymer resin. This methodology has high potential for trace analysis in a large variety of applications that suffer from the "strong solvent effect".

Flexible Single-Crystal Perovskite Photodetectors via Polymer-Controlled Transfer.

The large-sized perovskite single-crystal sheet (SCS) serves as the ideal research platform for perovskite photodetectors due to its outstanding carrier photophysics, pronounced geometric aspect ratio, and ultrahigh material utilization rate. However, its performance in flexible device applications is relatively lackluster due to the rigid and brittle nature of the three-dimensional cubic lattices. In this work, the indium tin oxide (ITO)-based multimillimeter-sized MAPbBr3 SCS is transformed into MAPbI3 SCS via ion exchange strategy. Significantly, we proposed and implemented a polymer-controlled transfer strategy─utilizing the dichloromethane (DCM) solution of poly(methyl methacrylate) (PMMA)─to nondestructively transfer the whole perovskite SCS off the ITO substrates and subsequently adhere it onto a flexible polyethylene terephthalate (PET) substrate of interdigital electrode, thereby fabricating a lateral-structured photodetector with a PMMA-SCS-Au-PET multilayer configuration. The tight self-encapsulation between the top PMMA membrane and the bottom PET substrate imparts excellent waterproof stability and concurrently excellent mechanical flexibility to these devices; additionally, the MAPbI3 device exhibits comprehensively superior performance to the MAPbBr3 one. This work represents a proactive attempt and exploration of the high-performance advancement of large-sized SCS photodetectors, undoubtedly introducing novel momentum and solutions to this domain.

Mono and binuclear Pt(II) complexes incorporated with NHC ligands: syntheses, photophysical properties, and acid vapor responses

Three mononuclear complexes (PtL1H, PtL2H, and PtL3H) and one binuclear complex (Pt2L1) have here been prepared using the bis-carbene ligand of 1,3-propylene-bis(1,3-dihydro-3-butyl-2H-imidazol-2-ylidene) and one of three rigid planar ligands of dibenzo[f,h]quinoxaline (L1H2), dibenzo[a,c]phenazine (L2H2), and tribenzo[a,c,i]phenazine (L3H2). These four complexes were fully characterized by nuclear magnetic resonance (NMR), high-resolution mass spectrometry (HRMS), and elemental analyses. Moreover, the two binuclear complexes Pt2L2 and Pt2L3 could not be isolated, but Pt2L3 was isolated and characterized by single-crystal X-ray diffraction (XRD). Complexes PtL1H, PtL2H, and Pt2L1 exhibited phosphorescence in N2-degassed dichloromethane (DCM) solution at 563 nm, 656 nm, and 624 nm, respectively. Also, Pt2L1 exhibited triplet emission at 553 nm in a 2 wt% PMMA film, with the highest Ф of 63 % and τ of 23.8 μs. Moreover, complexes PtL1H and Pt2L1 were deposited on quartz plates to monitor formic acid vapor and acetic acid vapor. The plates that were covered with PtL1H exhibited phosphorescent quenching in both formic acid and acetic acid. However, the plates that were covered with Pt2L1 did only show a prompt response to formic acid, but were not sensitive to acetic acid.

Elucidating the Mechanism of Efficient Eu(III) and Yb(III) Sensitisation from a Re(I) Tetrazolato Triangular Assembly.

The reaction of Re(CO)5Br with deprotonated 1H-(5-(2,2':6',2''-terpyridine)pyrid-2-yl)tetrazole yields a triangular assembly formed by tricarbonyl Re(I) vertices. Photophysical measurements reveal blue-green emission with a maximum at 520 nm, 32 % quantum yield, and 2430 ns long-lived excited state decay lifetime in deaerated dichloromethane solution. Coordination of lanthanoid ions to the terpyridine units red-shifts the emission to 570 nm and also reveals efficient (90 %) and fast sensitisation of both Eu(III) and Yb(III) at room temperature, with a similar rate constant kET on the order of 107 s-1. Efficient sensitisation of Eu(III) from Re(I) is unprecedented, especially when considering the close proximity in energy between the donor and acceptor excited states. On the other hand, comparative measurements at 77 K reveal that energy transfer to Yb(III) is two orders of magnitude slower than that to Eu(III). A two-step mechanism of sensitisation is therefore proposed, whereby the rate-determining step is a thermally activated energy transfer step between the Re(I) centre and the terpyridine functionality, followed by rapid energy transfer to the respective Ln(III) excited states. At 77 K, the direct Re(I) to Eu(III) energy transfer seems to proceed via a ligand-mediated superexchange Dexter-type mechanism.

Effect of Pyrrolidinedithiocarbamate Ligand on the Luminescence Properties of Heteroligand Samarium and Europium Complexes: Experimental and Theoretical Study.

The photophysical properties of two isostructural heteroligand lanthanide complexes of general formula Ln(pdtc)3(phen) (pdtc = pyrrolidinedithiocarbamate anion, phen = 1,10-phenanthroline), Ln = Sm3+ (1), Eu3+ (2)) were studied in solid state and dichloromethane (DCM) solution. The two lanthanide complexes were investigated by experimental techniques for structural (single-crystal X-ray diffraction analysis of 1, powder XRD, TG-DTA) and spectroscopic [electron paramagnetic resonance (EPR), infrared (IR), ultraviolet-visible (UV-vis), photoluminescence (PL)] characterization. DFT/TDDFT/ωB97xD and multireference SA-CASSCF/NEVPT2 calculations with perturbative spin-orbit coupling corrections were applied to construct the Jablonski energy diagrams and to discuss the excited state energy transfer mechanism with competing excited state processes and possible sensitized mechanism of metal-centered emission. The first excited state (S1) involved in the excited state energy transfer L(antenna)-to-Ln was predicted to have interligand (pdtc-to-phen) charge transfer character in contrast to the previously predicted ligand-to-metal charge transfer character. The theoretical consideration showed similar relaxation paths and luminescence quenching channels and appropriate Donor*(phen)-Acceptor*(Ln3+) energy gap for 1 and 2. The experimental measurements in the solid state, however, showed efficient luminescence and good ability to convert UV to visible light only for the Sm(pdtc)3(phen) complex. The minor emission of 2 was explained by partial reduction of Eu3+, confirmed by EPR and calculated electron density distribution data.

Photophysical, cyclic voltammetry, electron paramagnetic resonance, X-ray molecular structure, DFT calculations and molecular docking study of a new Mn(III) metalloporphyrin

Herein, we have presented a new manganese(III) metalloporphyrin, named, based on the X-ray molecular structure, the bis(4-dimethylaminopyridine)[meso‑tetra(para-chlorophenyl)porphyrinato]manganese(III) triflate 1.56 chloroform solvate 0.22 n-hexane solvate 0.22 hydrate with the following formula:[MnIII(TClPP)(DMAP)2](SO3CF3)·0.22(C6H14)·1.56(CHCl3)·0.22(H2O) (complex I).This coordination compound was characterized by FT-IR and cyclic voltammetry. The dichloromethane solution UV/Vis spectrum of I is typical of a Mn(III) high-spin (S = 2) porphyrin complex with a redshifted Soret band with λmax value of 487 nm. The single crystal X-diffraction technique was used to determine the molecular structure of our new Mn(III) bis(DMAP) porphyrin complex. Electron paramagnetic resonance (EPR) spectroscopy confirms that this new 3d4 Mn(III) metalloporphyrin (a non-Kramers system) in solid state is high-spin (S = 2). DFT/TD-DFT calculations on complex I were investigated, including (i) the molecular structure optimization using the DFT/B3LYP-D3/LanL2DZ level of theory, (ii) the frontier molecular orbital calculations and the deduction of the global indices of activities, (iii) the molecular electronic potential analysis (MEP), and (iv) the QTAIM and NCI-RDG analyses. Furthermore, complex I was tested against diverse amino acids of the selected Bcl-2 proteins using docking calculations.

Experimental and theoretical study of the photochemical properties and acidochromism of nonconventional 2,4,6-triarylpyridine-based materials

2,4,6-Triarylpyridines (TAPs) represent a versatile class of N-heterocycles with broad applications in many fields. This study presents an investigation on photochemical properties and acidochromism behavior of novel 2,6-bis(4-(dodecyloxy)phenyl)-4-(4-substituted-phenyl)pyridine-based derivatives (1a-1g). Photochemical study in dichloromethane (DCM) and acetone (ACT) solutions showed a small solvent effect for the TAP derivatives, except for the carbazole derivative 1a, which was characterized as the most emissive material in all conditions, but especially in DCM solution for blue emission (λEM = 406 nm, ϕf = 0.36). The presence of electron-donating groups at the 4-phenyl moiety contributes to more intense and redshifted emissions in both DCM and ACT solutions, as well as in the solid state. In aqueous ACT, while TAPs bearing EDGs such as 1a presented more intense emissions depending on the water fraction, an opposite effect was verified for fluorinated derivative 1f. The acidochromism of selected TAPs 1a and 1f (fluorinated derivative) in aqueous acetone was characterized by the decreasing of the emission intensity at 436 nm and 388 nm, respectively, in the presence of aqueous HCl for both TAPs, however, the protonated 1f showed strong emission in higher wavelength (λEM = 476 nm) in acidic medium. A 1H NMR study allowed a better understanding of the structural features associated to the acidochromism. The photochemical and acidochromism results obtained for the TAP derivatives are strongly supported by computational results, and particularly noteworthy is the favoring of the resonance effect as consequence of the decreasing in the torsion angle between the 4-alkoxyaryl substituents and the pyridine core after protonation of 1f. The emissive properties and acidochromism capacity of 1a and 1f allowed the potential application of TAP-adsorbed paper strips as disposable sensors for qualitative detection of gaseous HCl.

Cu-porphyrin-based polymers in electroreduction reactions of gases

In this work, the electrochemical properties of Cu-complexes of di- and tri-amino-substituted tetraphenylporphyrins in dichloromethane were investigated by the cyclic voltammetry method. Electrooxidation of porphyrins in a dichloromethane solution produced polyporphyrin films on the electrode. The formation of polymers occurs through the amino groups of phenyl substituents with the generation of phenazine and dihydrophenazine fragments. The surface morphology and thickness of polyporphyrin films were studied using a scanning electron microscope. The surface of the poly-Cu5,15-di(4′-aminophenyl)-10,20-diphenylporphyrin film is a network of fibers of about 5 µm long and 0.2–0.3 µm thick. The film thickness is 14 µm. The surface of poly-Cu5,10,15-tri(4′-aminophenyl)-20-phenylporphyrin has large branched agglomerates of indefinite shape; the film thickness is 22 µm. The catalytic activity of the obtained polyporphyrin films in oxygen and carbon dioxide electroreduction reactions were evaluated. Poly-Cu5,10,15-tri(4′-aminophenyl)-20-phenylporphyrin was found to be more catalytically active in both reactions, which is evidently associated with a more developed surface of the polymer.

Synthesis and Properties of Cyclic π-Conjugated Molecules and Their Dication and Monoradical Cation.

We synthesized cyclic π-conjugated molecules by double Friedel-Crafts reaction of amino group-substituted 1,2-bis(2-phenylethynyl)benzene with Meldrum's acid derivative. The structures of the cyclic π-conjugated molecules were determined by single-crystal X-ray structure analysis. The oxidation of the dimethylamino group-substituted π-conjugated molecule with NOBF4 gave a closed-shell dication that is stable at >210 °C. The monoradical cation of the di(4-methoxyphenyl)amino group-substituted π-conjugated molecule is stable in dichloromethane solution (half-life of nearly 15 days) and shows near-infrared absorption.

DPPM-Bridged Binuclear Pt(II) Pincer Complexes: Chemistry, Structure, and Photophysics in Solution Revisited.

A series of luminescent binuclear ([dppm{Pt(NNC)}2]2+) and mononuclear ([PPh3Pt(NNC)]+) complexes containing pincer ligands were synthesized and characterized. Photophysical characteristics of both types of complexes were studied in dichloromethane solution. In the solid phase, the binuclear compounds adopt a syn configuration where the {Pt(NNC)} fragments are held together due to intramolecular Pt-Pt bonding and π-stacking of the pincer ligand aromatic systems. Analysis of the complexes' molecular structure in solution by multinuclear NMR spectroscopy showed that the stacked intramolecular configuration is retained in fluid media, which is in complete agreement with a considerable red shift of the emission wavelength due to formation of the intramolecular Pt-Pt bond, leading to the transformation of an emissive excited state to 3MMLCT. It was also found that triethylamine quenches the emission of both types of complexes; the mechanism of quenching is a combination of dynamic and static channels of excited-state deactivation. In the case of binuclear complexes, deprotonation of the dppm methylene bridge by triethylamine also contributes to the chromophore quenching. To explain the observed chemistry of binuclear complex interactions with Et3N, a chemical equilibrium scheme was suggested, which was confirmed by quantitative monitoring of the 31P signal variations as a function of triethylamine concentration.

Photocurrent, electrochemical characteristic and photodegradation of two Ag20 cage isomers co-constructed by thiol and carboxylate/sulfonate and induced by CO32– template

Assembly of AgStBu and PhCOOH ligands with the assistance of soluble silver salt CH3COOAg/CF3SO3Ag in methanol, N, N-dimethylformamide (DMF) and dichloromethane solution, yielded two Ag20 cage isomers co-constructed by thiol and carboxylate/sulfonate ligands encapsulating a CO32– anion template, [(CO32–)@Ag20(StBu)10(PhCOO)4(CH3COO)4(DMF)4] (1) and [(CO32–)@Ag20(StBu)10(PhCOO)6(CF3SO3)2(DMF)4]·2DMF (2). The CO32– anion template was generated in situ by fixing atmospheric CO2. The precise structures of 1 and 2 were confirmed by single-crystal X-ray diffractometry (SCXRD). The thermal stability of compounds 1 and 2 was proved by thermogravimetric (TG) analysis, and their solution stability was characterized by nuclear magnetic resonance hydrogen spectroscopy (1H NMR). The absorption spectra, photocurrent responses, and luminescence of compounds 1 and 2 were investigated. In addition, the photodegradation of methylene blue (MB) and cyclic voltammetry characteristic curves of 1 and 2 were also studied.

Crystal structure of 4,4′-(disulfanediyl)dipyridinium chloride triiodide

4,4′-(Disulfanediyl)dipyridinium chloride triiodide, C10H10N2S2 2+·Cl−·I3 −, (1) was synthesized by reaction of 4,4′-dipyridyldisulfide with ICl in a 1:1 molar ratio in dichloromethane solution. The structural characterization of 1 by SC-XRD analysis was supported by elemental analysis, FT–IR, and FT–Raman spectroscopic measurements.

Experimental investigation of PCL‐based composite material fabricated using solvent‐cast 3D printing process

AbstractBone tissue engineering relies on scaffolds with enhanced mechanical properties, achievable through 3D printing techniques. Our study focuses on enhancing mechanical properties using a solvent‐cast 3D printing method. For this, poly‐ε‐caprolactone (PCL) reinforced with polyhydroxybutyrate (PHB), and synthetic fluorapatite (FHAp) nanopowders were utilized, immersed in a solution of dichloromethane (DCM) and dimethylformamide (DMF). Sol–gel method was used to synthesized FHAp, and the XRD pattern confirmed crystalline FHAp presence, with notable peaks at 2θ values of 31.937°, 33.128°, 32.268°, and 25.864°. Moreover, composites exhibited nonchemical PCL‐PHB/FHAp interactions, with PHB and FHAp crystallographic planes evident. Surface roughness, assessed via RMS values, showed progressive increases with higher PHB and FHAp content. Tensile strength peaked at 19% wt/v of PHB, with varied effects of FHAp. Compressive strength reached its apex at 30% wt/v of FHAp, with higher PHB content consistently enhancing strength. Flexural strength notably increased with PHB, peaking at 19% wt/v, and further with FHAp. Young's modulus rose with both PHB and FHAp content. Hardness increased with PHB and FHAp, notably peaking at 30% wt/v of FHAp. Cell viability improved with PHB, showing varied responses to FHAp. Hemocompatibility evaluations indicated low hemolysis percentages, especially in balanced PHB/FHAp compositions. These findings highlight the crucial role of composite compositions in tailoring mechanical and biological properties for optimal bone scaffold design, promising advancements in tissue regeneration technologies.

Degradation of nanofiber layers made of biobased polyamide 4

Based on renewable raw materials, polyamide 4 has excellent mechanical properties, high hydrophilicity, and cotton-like water sorption. The problem is its low thermal stability near its melting point, which does not allow melt processing. With the development of the technology of electrostatic spinning of polymers from solutions, the attention of researchers has returned to polyamide 4. In this work, nanofiber layers of polyamide 4 with molar masses of 18,000 and 280,000 g/mol and diameters of 350 ± 60 and 270 ± 10 nm, respectively, were prepared by electrostatic spinning from a mixed solution of formic acid and dichloromethane. Subsequently, the layers were subjected to degradation in phosphate buffer at 37 and 60 °C. The electrostatic spinning process was shown to result in a decrease in the molar mass of the samples. During degradation in buffer at pH 7.4, the molar mass does not change significantly, but there is a change in the structure of the nanofibrous layers by bonding of the fibers, especially for low molecular weight PA4. In contrast to other studies, polyamide 4 is hydrolytically stable even in the form of nanofiber layers.

Chitin nanocrystals-stabilized emulsion as template for fabricating injectable suspension containing polylactide hollow microspheres

One of the promising applications of rod-like chitin nanocrystals (ChNCs) is the use as particle emulsifier to develop Pickering emulsions. We reported a ChNC-stabilized oil-in-water emulsion system, and developed a Pickering emulsion-templated method to prepare polylactide (PLA) hollow microspheres here. The results showed that both non-modified ChNCs and acetylated ChNCs could well emulsify the dichloromethane (DCM) solution of PLA-in-aqueous mannitol solution systems, forming very stable emulsions. At the same oil-to-water ratios and ChNC loadings, the emulsion stability was improved with increasing acetylation levels of ChNCs, accompanied by reduced size of droplets. Through the solvent evaporation, the PLA hollow microspheres were templated successfully, and the surface structure was also strongly dependent on the acetylation level of ChNCs. At a low level of acetylation, the single-hole or multi-hole surface structure formed, which was attributed to the out-diffusion of DCM caused by the solvent extraction and evaporation. These surface defects decreased with increased acetylation levels of ChNCs. Moreover, the aqueous suspension with as-obtained PLA microspheres revealed shear-thinning property and good biocompatibility, thereby had promising application as injectable fillers. This work can provide useful information around tuning surface structures of the Pickering emulsion-templated polymer hollow microspheres by regulating acetylation level of ChNCs.

Characterization of the Coordination and Solvation Dynamics of Solvated Systems─Implications for the Analysis of Molecular Interactions in Solutions and Pure H2O.

The characterization of solvation shells of atoms, ions, and molecules in solution is essential to relate solvation properties to chemical phenomena such as complex formation and reactivity. Different definitions of the first-shell coordination sphere from simulation data can lead to potentially conflicting data on the structural properties and associated ligand exchange dynamics. The definition of a solvation shell is typically based on a given threshold distance determined from the respective solute-solvent pair distribution function g(r) (i.e., GC). Alternatively, a nearest neighbor (NN) assignment based on geometric properties of the coordination complex without the need for a predetermined cutoff criterion, such as the relative angular distance (RAD) or the modified Voronoi (MV) tessellation, can be applied. In this study, the effect of different NN algorithms on the coordination number and ligand exchange dynamics evaluated for a series of monatomic ions in aqueous solution, carbon dioxide in aqueous and dichloromethane solutions, and pure liquid water has been investigated. In the case of the monatomic ions, the RAD approach is superior in achieving a well separated definition of the first solvation layer. In contrast, the MV algorithm provides a better separation of the NNs from a molecular point of view, leading to better results in the case of solvated CO2. When analyzing the coordination environment in pure water, the cutoff-based GC framework was found to be the most reliable approach. By comparison of the number of ligand exchange reactions and the associated mean ligand residence times (MRTs) with the properties of the coordination number autocorrelation functions, it is shown that although the average coordination numbers are sensitive to the different definitions of the first solvation shell, highly consistent estimates for the associated MRT of the solvated system are obtained in the majority of cases.

Exploring Cellulose Triacetate Nanofibers as Sustainable Structuring Agent for Castor Oil: Formulation Design and Rheological Insights.

Developing gelled environmentally friendly dispersions in oil media is a hot topic for many applications. This study aimed to investigate the production of electrospun cellulose triacetate (CTA) nanofibers and to explore their potential application as a thickening agent for castor oil. The key factors in the electrospinning process, including the intrinsic properties of CTA solutions in methylene chloride (DCM)/ethanol (EtOH), such us the shear viscosity, surface tension, and electrical conductivity, were systematically studied. The impact of the CTA fiber concentration and the ratio of DCM/EtOH on the rheological properties of the gel-like dispersions in castor oil was then investigated. It was found that dispersions with a non-Newtonian response and above a critical concentration (5 wt.%), corresponding to approximately 2-2.5 times the entanglement concentration, are required to produce defect-free nanofibers. The average fiber diameter increased with CTA concentration. Further, the morphology and texture of the electrospun nanofibers are influenced by the ratio of solvents used. The rheological properties of dispersions are strongly influenced by the concentration and surface properties of nanofibers, such as their smooth or porous textures, which allow their modulation. Compared to other commonly used thickeners, such as synthetic polymers and metal soaps, CTA electrospun nanofibers have a much higher oil structuring capacity. This work illustrated the potential of using CTA nanofibers as the foundation for fabricating gel-like dispersions in oil media, and thus exerting hierarchical control of rheological properties through the use of a nanoscale fabrication technique.