Palladium(ii)-directed formation of pseudo-rotaxanes : the 3 + 1 approach to threaded species using square-planar geometries

Palladium(II) has been used as a gathering and threading metal centre, using a terpy-incorporating ring and a string-like compound containing a monodentate ligand (pyridine derivative). Preliminary experiments show that the fourth ligand of the square planar complex can be exchanged (pyridine-based ligand/aliphatic amine) by modifying the H+ concentration of the medium, allowing us to envision new molecular machines set in motion by protonation/deprotonation.