Reversibly tunable helix inversion in supramolecular gels trigged by Co2+

Terpyridine-based ligands form octahedral complexes with Co2+ at Low cation concentrations to form helical assemblies which provide a supramolecular gel framework. Increasing the Co2+ concentration above 0.6 equiv. reveals a second, co-existing square pyramidal complex derived assembly, having a distinct helicity. While this geometry dominates at 1 equiv. of Co2+, we find this unique form of helical inversion to be fully reversible and controllable.