Improved Efficiency of Molecular-Gel Formation by Adjusting Preorganization of Amino-Acid-Derived Flexible Molecules: A NMR and Thermodynamic study.
Chemphyschem
; 17(13): 2008-12, 2016 07 04.
Article
en En
| MEDLINE
| ID: mdl-26990038
ABSTRACT
The efficiency of the formation of molecular gels of simple derivatives of l-valine and l-isoleucine is greatly improved in different organic solvents when a hexyl fragment is replaced by a bulkier cyclohexyl one. A study using NMR and IR spectroscopy provides information on the preferred conformations of the molecules, indicating that the cyclohexyl moiety precludes intramolecular H bonding and preorganises the system for intermolecular interactions, which are responsible for fiber formation. NMR data of the gels provides thermodynamic data on fibrillization, revealing that the origin of this effect is mainly entropic. Electron microscopy (SEM and TEM) images show fibrillar and tape-like objects, which are observed commonly in molecular gels. Rheological measurements reveal significant differences between cyclohexyl and hexyl appended gelators. These findings could contribute to the rational design of small, flexible, building blocks for self-assembly.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Termodinámica
/
Valina
/
Isoleucina
Idioma:
En
Revista:
Chemphyschem
Asunto de la revista:
BIOFISICA
/
QUIMICA
Año:
2016
Tipo del documento:
Article
País de afiliación:
España