Monitoring the redox-driven assembly/disassembly of a dicopper(I) helicate with an auxiliary fluorescent probe.

The assembly/disassembly of a dicopper(I) helicate with a bis-bidentate imine-quinoline ligand is driven by the Cu(II)/Cu(I) redox change and is signaled by a fluorescent probe bearing a -COO(-) group (coumarine 343). The probe coordinates the Cu(II) center of the monomeric complex, which quenches its emission (fluorescence off), and is released upon reduction and formation of the Cu(I) helicate (fluorescence on).