Terminal is important for the helicity of the self-assemblies of dipeptides derived from alanine.

The organization of peptides and proteins attracts much attention, due to the biofunctionalities of the self-assemblies. Herein, four dipeptides derived from alanine were synthesized. It was found that the handedness of their self-assemblies was controlled by the chirality of the alanines at the terminals. The organic self-assemblies were studied using circular dichroism, (1)H NMR, Fourier transform infrared, field-emission electron microscopy, transmission electron microscopy, and X-ray diffraction. The results indicated that the electrostatic interactions among the carboxylate groups and H-bondings among the amide groups at the terminals play important roles in the formation of the organic self-assemblies.