One‐Step Directed Self‐Assembly of Molecular Closed Four‐Link Chains and Borromean Links

Despite substantial advancements in the synthesis of mechanically interlocked molecules (MIMs), the efficient construction of higher order links remains a formidable challenge. Herein, we report the highly efficient one-step directed construction of a series of unprecedented molecular closed four-link chains (84 1 metalla-links), achieved through the synergistic assembly of coordination-driven and aromatic stacking interactions involving binuclear rhodium/iridium precursors and bis-dentate benzothiadiazole derivative ligands. Meanwhile, modulating the substituent positions of the pyridine groups in the ligand resulted in a change in topological structure, leading to the formation of two molecular Borromean links ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:semantics><mml:msubsup><mml:mn>6</mml:mn> <mml:mn>2</mml:mn> <mml:mn>3</mml:mn></mml:msubsup> <mml:annotation>${6_2^3 }$</mml:annotation> </mml:semantics> </mml:math> metalla-links). The molecular configurations of the abovementioned metalla-links were clearly identified through mass spectrometry, NMR, and single-crystal X-ray diffraction. Furthermore, structural transformation between the molecular Borromean links and corresponding monocycles was achieved through concentration effects, as validated by solution-state NMR spectroscopy investigations.