Self-Assembly of Tripodal Squaraines: Cation-Assisted Expression of Molecular Chirality and Change from Spherical to Helical Morphology

摘要

Inspired by the elegance and complexity of natural helical assemblies, from the nanoscopic DNA double helix and collagen triple helix to microscopic viruses and macroscopic sea shells, chemists have been trying to mimic the structure and functions of biological macromolecules in self-assembled synthetic molecules.[1–7] The most challenging task in these studies is the control of the overall morphology and the supramolecular chirality of the selfassembled architectures within the nanometer-to-micrometer length scale.[8] Although a few reports on reversible morphology transitions caused by external stimuli have appeared,[9] a spherical-to-helical change induced by a cation was previously unknown. However, in an interesting report Nolte and co-workers described the loss of helicity in a phthalocyanine-derived self-assembly in the presence of potassium ions.