Donor−Acceptor-Promoted Gelation of Polyaromatic Compounds
| Autor: | Ovadia Lev, Artem Melman, Dan Rizkov, Jenny Gun, Ron Sicsic |
|---|---|
| Rok vydání: | 2005 |
| Předmět: |
chemistry.chemical_classification
Molar mass medicine.diagnostic_test Spectrum Analysis Surfaces and Interfaces Electron acceptor Condensed Matter Physics Photochemistry Solvent chemistry.chemical_compound Hydrocarbon Monomer chemistry Cyclization Covalent bond Spectrophotometry Microscopy Electron Scanning Electrochemistry medicine Proton NMR Organic chemistry Polycyclic Compounds General Materials Science Gels Spectroscopy |
| Zdroj: | Langmuir. 21:12130-12138 |
| ISSN: | 1520-5827 0743-7463 |
| DOI: | 10.1021/la052155w |
| Popis: | Low molecular mass organogels are nonconventional polymeric structures in which a minute amount of low molecular weight compound can reversibly gelify the whole solution without forming covalent bonds between the monomers. In this article, we demonstrate that certain electron acceptors (taking dinitrobenzoates as model compounds) that are incapable of gelifying the solvent on their own can assemble as much as a 15-16-fold larger amount of polyaromatic hydrocarbons (PAHs) and form two-component donor-acceptor organogels in different solvents. At the core of the long-range order stand donor-acceptor pairs. We assess our claims by detailed 1H NMR, spectrophotometry, fluorescence, and time-resolved fluorescence methods. The thermodynamics of the gelation process is described on the basis of temperature dependent 1H NMR studies. We believe that, in this case, 1H NMR provides direct quantification of the dissolved concentrations of the different species and therefore provides a direct way to measure the enthalpy, entropy, and free energy associated with gel formation. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|