Dinuclear helicate or mononuclear pincer lanthanide complexes from one ligand: stereo-controlled assembly and catalysis

By varying the metal/ligand ratio, either dinuclear triple helicates (Lambda Lambda/Delta Delta-La2L3R/S) or mononuclear pincer complexes (Lambda/Delta-LaLR/S) can be stereo-selectively obtained from the same chiral bis-tridentate ligand (L-R/S). Due to the open metal sites available in both complexes, their catalytic properties have been demonstrated with the asymmetric Friedel-Crafts alkylation reactions.