Zinc(ii) driven intra-molecular electronic energy transfer in a supramolecular assembly held by coordinative interactions

In a MeOH solution the complex [Zn-II(L)](2+) gives an adduct with the coumarin-343 anion and an electronic energy transfer process takes place from the fluorophore placed on the ligand L to the fluorescent anion, according to a mechanism which can be reversively switched off-on following an acid-base input.