Synthesis and gelation properties of a new class of α-amino acid-based sector block dendrons

A new series of alpha-amino acid-based sector block dendrons containing alanine, phenylalanine, and valine dendritic sectors was prepared by a solution phase peptide coupling methodology. The structures of the dendrons were fully characterized by nuclear magnetic resonance and mass spectroscopy and by optical polarimetry, and their purities were determined by size exclusion chromatography. Some of the dendrons, especially those containing phenylalanine residues, were found to form strong physical gels with aromatic solvents. The gelation mechanism was further investigated by infra-red and circular dichroism spectroscopy. It was found that both inter-molecular hydrogen bonding and aromatic pi-pi stacking interactions were the main driving forces for gelation. (c) 2005 Elsevier Ltd. All rights reserved.