Silanol groups, triple bond SiOH, on the surface of silica were esterified with unsaturated alcohols and long-chain alcohols bearing thiol groups. The modified silicas obtained were used as substrates for a vulcanization-analogous reaction with sulfur catalyzed by zinc dimethyldithiocarbamate. Surface-esterified thiols could be smoothly converted to bridged polysulfides bonded to the silica surface, whereas the use of surface-esterified unsaturated alcohols led to removal of the surface-esterified alcohol from the silica surface. The materials were characterized by solid-state NMR and thermal and microanalytical analysis. The linking of surface-esterified alkenols and thiols by sulfide bridges was investigated by a numerical model for a flat surface. This showed that for a typical density of 3-4 micromol/m(2) surface groups, a statistical maximum of 70-75% of groups could be linked by S(n) bridges (n=2-4).
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1006/jcis.2002.8294 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
The role of cationic bridges in enhancing sulfamethoxazole adsorption onto montmorillonite.
Environ Geochem Health
January 2025
Yunnan Provincial Key Laboratory of Soil Carbon Sequestration and Pollution Control, Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, 650500, Yunnan, China.
The coexistence and interaction of free metal cations in the environment can significantly affect the migration of organic pollutants, leading to varied effects depending on environmental conditions. However, the mechanisms affecting the adsorption of organic pollutants in the presence of metal ions remain poorly understood due to limited molecular-level studies. This study investigated the adsorption behavior of sulfamethoxazole (SMX) on montmorillonite (MT) at different pH values (1.
View Article and Find Full Text PDFMesoporous Silica Nanoparticle Rigid Anchor Attached Pt Complex for Catalytic H/D Exchange of Aromatic Substrates.
Inorg Chem
January 2025
Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, United States.
A Pt(II) aqua complex supported by mesoporous silica nanoparticle (MSN)-immobilized sulfonated CNN pincer ligand featuring a rigid SiO tether was prepared. This hybrid material was tested as a catalyst in H/D exchange reactions of C(sp)-H bonds of selected aromatic substrates and DO-2,2,2-trifluoroethanol- (TFE-) mixtures or CDCOD acting as a source of exchangeable deuterium. The catalyst immobilization served as a means to not only enable the catalyst's recyclability but also minimize the coordination of sulfonate groups and the metal centers originating from different catalyst's moieties that would preserve reactive Pt(OH) fragments needed for catalytic C-H bond activation.
View Article and Find Full Text PDFMicrofluidics-enabled core/shell nanostructure assembly: Understanding encapsulation processes via particle characterization and molecular dynamics.
Adv Colloid Interface Sci
January 2025
Pharmaceutical Sciences Laboratory, Faculty of Science and Engineering, Åbo Akademi University, Biocity (3rd fl.), Tykistökatu 6A, 20520 Turku, Finland; Turku Bioscience Centre, University of Turku and Åbo Akademi University, Biocity (5th fl.), Tykistökatu 6A, 20520 Turku, Finland. Electronic address:
In the realm of hybrid nanomaterials, the construction of core/shell nanoparticles offer an effective strategy for encompassing a particle by a polymeric or other suitable material, leading to a nanocomposite with distinct features within its structure. The polymer shell can be formed via nanoprecipitation, optimized by manipulating fluid flow, fluid mixing, modulating device features in microfluidics. In addition to the process optimization, success of polymer assembly in encapsulation strongly lies upon the favorable molecular interactions originating from the diverse chemical environment shared between core and shell materials facilitating formation of core/shell nanostructure.
View Article and Find Full Text PDFIsolation and Identification of Mercury-Dissolved Organic Matter Complexes in Mercury-Humic Acid Suspensions.
Rapid Commun Mass Spectrom
April 2025
Department of Civil and Environmental Engineering, Syracuse University, Syracuse, New York, USA.
Rationale: The complexation with dissolved organic matter (DOM) is a pivotal factor influencing transformations, transport, and bioavailability of mercury (Hg) in aquatic environments. However, identifying these complexes poses a significant challenge because of their low concentrations and the presence of coexisting ions.
Methods: In this study, mercury-dissolved organic matter (Hg-DOM) complexes were isolated through solid-phase extraction (SPE) from Hg-humic acid suspensions, and complexes were putatively identified using ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS).
Elucidating Photochemical Conversion Mechanism of PDMS to Silica under Deep UV Light and Ozone.
J Phys Chem Lett
January 2025
School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States.
Photochemistry-based silica formation offers a pathway toward energy-efficient and controlled fabrication processes. While the transformation of poly(dimethylsiloxane) (PDMS) to silica (often referred to as SiO due to incomplete conversion) under deep ultraviolet (DUV) irradiation in the presence of oxygen/ozone has experimentally been validated, the detailed mechanism remains elusive. This study demonstrates the underlying molecular-level mechanism of PDMS-to-silica conversion using density functional theory (DFT) calculations.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!