Successive Sulfur Oxidation Directs Topological Transformation From 4 ₁ Knot to 632$6_3^2$ Link

Achieving transformation between different types of topologies remains a challenge in supramolecular chemistry. Herein, sulfur oxidation was utilized as the stimuli to trigger topological transformations from knots to links. The process began with a thioether-type precursor, M (4₁ metallic knot), which was synthesized by self-assembling the sulfur-bridged ligand L with building block B in high yield. Following oxidation reactions, we successfully transformed the octanuclear 4₁ metallic knot (M) with four crossing points into a sulfoxide-type dodecanuclear <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:semantics><mml:msubsup><mml:mn>6</mml:mn> <mml:mn>3</mml:mn> <mml:mn>2</mml:mn></mml:msubsup> <mml:annotation>$6_3^2$</mml:annotation></mml:semantics> </mml:math> metallic link (M-O) with six crossing points as an intermediate product, and then to a sulfone-type dodecanuclear <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:semantics><mml:msubsup><mml:mn>6</mml:mn> <mml:mn>3</mml:mn> <mml:mn>2</mml:mn></mml:msubsup> <mml:annotation>$6_3^2$</mml:annotation></mml:semantics> </mml:math> metallic link (M-2O) with six crossing points, which achieves a dual leap in both metal nuclearity and crossing complexity. Remarkably, the key to the transformation lies in using the embedded S-centres of M as molecular triggers and stepwise oxidation (-S-→-S(O)-→-S(O)₂-) enabled precise modulation of the geometric configuration of the sp³ S-centres, drastically altering the range of accessible coordination vectors and inducing conformational self-adaptation among components. This strategy establishes a novel oxidation-mediated interconversion paradigm among complex topologies, offering new insights for designing dynamic molecular triggers in intelligent material systems.