A template-free strategy for the synthesis of highly stable trefoil knots

Abstract Molecular knots and other topological architectures have attracted increasing attention over the past few decades. However, in solution, these architectures usually exist as mixtures due to their instability, which limits their potential applications. Herein, two molecular building blocks with large conjugated-π areas and two nonrigid ligands with suitable flexibility were selectively employed to obtain complicated architectures with high stabilities. Remarkably, three very stable trefoil knots were obtained, as expected in advance, whose high stabilities can be attributed to π-π stacking, C–H···π interactions and hydrogen bonds. This research provides a strategy to obtain complicated molecular architectures with high stabilities.