Abstract
Urea derivatives 1 and 2, synthesized from adenosine, were designed as low-molecular-weight gelators. Hydrophobic groups have been introduced into all or part of the hydroxy groups of the hydrophilic ribose moiety of 1 and 2 to control the solvophilicity of the molecules and their aggregates. Compound 2 selectively formed supramolecular gels in halogenated solvents such as chloroform and 1,2-dichloroethane. The supramolecular gel of 2 and chloroform was thermally stable and its gel-to-sol phase transition temperature was higher than the boiling point of chloroform. The physical properties of the supramolecular gel were investigated by determining its viscoelastic properties using a rheometer. The supramolecular gel realized multiple stimuli-responsive reversible gel-sol phase transitions. The supramolecular gel showed reversible phase transition by repeated warming-cooling cycles accompanying with the gel-sol transitions. The supramolecular gel could undergo five repeated mechano-responsive gel-sol transitions. Gel-to-sol phase transition could also be achieved by adding various anions to the supramolecular gel, such as tetrabutylammonium fluoride. Regelation was realized by adding boron trifluoride etherate to the fluoride ion containing sol. Addition of methanol to the supramolecular gel also induced gel-to-sol phase transition. Regelation was realized by adding molecular sieves 4 Å to the suspension.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.