Macrocyclic ligands gIving access to robust photosensitizers based on copper complexes – MagicCopper

The MagicCopper project focuses on the preparation and study of robust copper(I) complexes with enhanced photophysical properties and displaying redox reversibility between the copper(I) and copper(II) states. Macrocyclic diphosphine and terpyridine ligands will be used to ensure the stabilization of the targeted heteroleptic [Cu(terpy)(PP)]+ complexes both in water and organic solvents. Steric bulk within a cyclodextrin cavity equipped with a diphosphine unit or topological constraints present in pseudorotaxanes based on macrocyclic terpyridine ligands are expected to prevent the formation of unwanted homoleptic complexes and stabilize photoactive [Cu(terpy)(PP)]+ ones. A further development will be the combination of the two types of macrocyclic ligands within mechanically interlocked systems. This feature should fully prevent ligand exchange reactions whatever the oxidation state of the metal center providing even higher stability to the targeted heteroleptic complexes. The design of robust photosensitizers based on these principles should ultimately bring new opportunities in photocatalysis by avoiding second and third row transition metal complexes that are in short supply and harmful to the environment.