Novel dumbbell-form low-molecular-weight gelators based on l-lysine: their hydrogelation and organogelation properties

Abstract

New L-lysine-based, dumbbell-form, low-molecular-weight gelators, in which two L-lysine derivatives are linked by alkylene spacers, were synthesized and their gelation abilities for aqueous solutions and organic solvents were examined. These gelators are amphiphilic gelators that function as not only hydrogelators but also as organogelators. In hydrogels, these gelators created a three-dimensional network by entanglement of self-assembled nanofibers via hydrogen bonding and van der Waals interactions. The hydrogel-broken temperatures (T_gel) depended on the carbon numbers of the alkylene spacers and showed an odd–even effect. The FT-IR and ¹H-NMR spectra demonstrated a difference in the intermolecular hydrogen bonding modes between the gelators of the even-numbered chains and odd-numbered chains.