Self-assembly of disk-shaped molecules to coiled-coil aggregates with tunable helicity

A disk-shaped molecule with chiral tails is shown to form Long fibers of mo lecular diameter and micrometer length by self-assembly in chloroform. The molecules are derived from crown ethers and contain a phthalocyanine ring. In the fibers, they have a clockwise, staggered orientation that Leads to a n overall right-handed helical structure. These structures, in turn, self-a ssemble to form coiled-coil aggregates with left-handed helicity. Addition of potassium ions to the fibers leaves their structure intact but blocks th e transfer of the chirality from the tails to the cores, leading to loss of the helicity of the fibers. These tunable chiral materials have potential in optoelectronic applications and as components in sensor devices.