Terpyridine-based ligands form octahedral complexes with Co(2+) at low cation concentrations to form helical assemblies which provide a supramolecular gel framework. Increasing the Co(2+) 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 Co(2+), we find this unique form of helical inversion to be fully reversible and controllable.

A unique system has been developed for quantifying G-quadruplex forming DNA down to picomolar levels for future applications in telomeric assessment. Pyrene-imidazolium captured in high amounts on the surface of reduced graphene oxide shells allows specific DNA sequence detection by complex formation resulting in release and fluorescence enhancement of pyrene-imidazolium.