Stereocontrolled Synthesis of Chiral [2]Catenanes by Coordination-Driven Self-Assembly

Chiral catenanes hold substantial research significance due to their potential applications in stereoselective catalysis, sensing, and chiroptical switching. However, achieving stereocontrolled synthesis of enantiopure supramolecular catenanes with crystallographically characterized structures remains challenging. Herein, we reported the successful construction of two pairs of chiral [2]catenanes with opposite handedness, achieved by coordination-driven self-assembly using pairs of ditopic monodentate ligands bearing L-/d-valine residues coordinated to two binuclear half-sandwich rhodium(III) units, respectively. The resultant metalla-[2]catenanes exhibit complex coconformational mechanical helical chirality and planar chirality arising from the point chirality of the ligands. The results are supported by single-crystal X-ray diffraction, NMR spectroscopy, mass spectrometry, and circular dichroism spectroscopy.