The mechanism behind the stability of organic nanoparticles prepared by liquid antisolvent (LAS) precipitation without a specific stabilizing agent is poorly understood. In this work, we propose that the organic solvent used in the LAS process rapidly forms a molecular stabilizing layer at the interface of the nanoparticles with the aqueous dispersion medium. To confirm this hypothesis, -octadecyltrichlorosilane (OTS)-functionalized silicon wafers in contact with water-solvent mixtures were used as a flat model system mimicking the solid-liquid interface of the organic nanoparticles. We studied the equilibrium structure of the interface by X-ray reflectometry (XRR) for water-solvent mixtures (methanol, ethanol, 1-propanol, 2-propanol, acetone, and tetrahydrofuran). The formation of an organic solvent-rich layer at the solid-liquid interface was observed. The layer thickness increases with the organic solvent concentration and correlates with the polar and hydrogen bond fraction of Hansen solubility parameters. We developed a self-consistent adsorption model via complementing adsorption isotherms obtained from XRR data with molecular dynamics simulations.
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http://dx.doi.org/10.1021/acs.langmuir.0c02745 | DOI Listing |
Molecules
November 2024
Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102A, HR-10000 Zagreb, Croatia.
In this study, we report the syntheses, crystal structures and magnetic properties of ternary copper(II) coordination compounds with l-homoserine (l-Hhser) and 1,10-phenanthroline (phen). Six new coordination compounds were obtained: [Cu(l-hser)(HO)(phen)]SO·5HO (), [Cu(μ-l-hser)(HO)(phen)][Cu(l-hser)(HO)(phen)](SO)∙12HO (), {[Cu(μ-l-hser)(HO)(phen)][Cu(μ-l-hser)(phen)]SO·6HO} (), {[Cu(μ-l-hser)(HO)(phen)]SO·3HO} (), [Cu(l-hser)(HO)(phen)][Cu(l-hser)(CHOH)(phen)]SO·4HO () and {[Cu(l-hser)(CHOH)(phen)][Cu(μ-l-hser)(phen)]SO·5CHOH} () It was shown that slight differences in water content in the synthetic mixtures highly influence the final product, so in some cases, two or three different products were obtained. The compounds were characterized by single-crystal X-ray diffraction and ESR spectroscopy.
View Article and Find Full Text PDFAnalyst
November 2024
School of Chemistry, Highfield Campus, Southampton, SO17 1BJ, UK.
Signal Amplification By Reversible Exchange (SABRE) can provide strong signal enhancement (SE) to an array of molecules through reversible exchange of parahydrogen (pH) derived hydrides and a suitable substrate coordinated to a transition metal. Among the substrates that can be used as a probe for hyperpolarised NMR and MRI, pyruvate has gained much attention. SABRE can hyperpolarise pyruvate in a low cost, fast, and reversible fashion that does not involve technologically demanding equipment.
View Article and Find Full Text PDFPDA J Pharm Sci Technol
October 2024
Jordi Labs, 200 Gilbert St., Mansfield, MA, 02048.
The analysis of extractables and leachables and subsequent risk assessment is an important aspect of the determination of biocompatibility for many medical devices. Leachable chemicals have the potential to pose a toxicological risk to patients, and therefore it is required that they be adequately characterized and assessed for potential safety concerns. One important consideration in the assessment of leachables is the choice of a suitable simulating solvent intended to replicate the use condition for the device and its biological environment.
View Article and Find Full Text PDFACS Omega
August 2024
Department of Mathematics and Natural Sciences, Gulf University for Science and Technology, Mubarak Al-Abdullah, Hawally 32093, Kuwait.
Synthesis of various polycyclic aromatic hydrocarbons (PAHs) from a palladium-catalyzed [3 + 2] cyclocondensation reaction is reported herein. The design strategy consisted of reacting the sterically hindered 1,2-bis(3,5-di-butylphenyl)acetylene with myriad brominated anthracene and pyrene surrogates, resulting in the formation of target molecules and , which exhibited excellent solubility in commonly used organic solvents and unveiled prominent aggregation-induced emission (AIE) characteristics in tetrahydrofuran and water solvent mixtures. Calculations using density functional theory (DFT) were utilized to validate both the contorted structures of the target molecules and their electronic conjugation featuring HOMO-LUMO band gaps (Δ) in the range of ∼2.
View Article and Find Full Text PDFMolecules
August 2024
Department of Chemistry and Biochemistry, Kent State University, Kent, OH 44242, USA.
Photoactive -hydroxysulfonamides photocaged with the (6-bromo-7-hydroxycoumarin-4-yl)methyl chromophore have been successfully synthesized, and the mechanisms of photodecomposition investigated for two of the compounds. Upon irradiation up to 97% of a diagnostic marker for (H)NO release, sulfinate was observed for the trifluoromethanesulfonamide system. In the absence of a species that reacts rapidly with (H)NO, (H)NO instead reacts with the carbocation intermediate to ultimately generate ()-BHC-oxime and ()-BHC-oxime.
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