Unexpected self-assembly of a homochiral metallosupramolecular M4L4 catenane

Abstract

Two enantiomerically pure 9,9'-spirobifluorene-based bis(pyridine) ligands 1 and 2 were prepared to study their self-assembly behavior upon coordination to cis-protected palladium(II) ions. Whereas the sterically more demanding ligand, 2, gave rise to the expected dinuclear metallosupramolecular M2L2 rhombi, the sterically less demanding ligand, 1, acts as a template to give rise to a homochiral metallosupramolecular M4L4 catenane.

Keywords: 9,9′-spirobifluorenes; catenanes; metallosupramolecular chemistry; palladium complexes; self-assembly.